WorldWideScience

Sample records for co2 power cycle

  1. sCO2 Power Cycles Summit Summary November 2017.

    Energy Technology Data Exchange (ETDEWEB)

    Mendez Cruz, Carmen Margarita; Rochau, Gary E.; Lance, Blake

    2018-04-01

    Over the past ten years, the Department of Energy (DOE) has helped to develop components and technologies for the Supercritical Carbon Dioxide (sCO2) power cycle capable of efficient operation at high temperatures and high efficiency. The DOE Offices of Fossil Energy, Nuclear Energy, and Energy Efficiency and Renewable Energy collaborated in the planning and execution of the sCO2 Power Cycle Summit conducted in Albuquerque, NM in November 2017. The summit brought together participants from government, national laboratories, research, and industry to engage in discussions regarding the future of sCO 2 Power Cycles Technology. This report summarizes the work involved in summit planning and execution, before, during, and after the event, including the coordination between three DOE offices and technical content presented at the event.

  2. COMPARISON OF S-CO2 POWER CYCLES FOR NUCLEAR ENERGY

    Directory of Open Access Journals (Sweden)

    Ladislav Vesely

    2016-12-01

    Full Text Available The supercritical carbon dioxide (S-CO2 is a possible cooling system for the new generations of nuclear reactors and fusion reactors. The S-CO2 power cycles have several advantages over other possible coolants such as water and helium. The advantages are the compression work, which is lower than in the case of helium, near the critical point and the S-CO2 is more compact than water and helium. The disadvantage is so called Pinch point which occurs in the regenerative heat exchanger. The pinch point can be eliminated by an arrangement of the cycle or using a mixture of CO2. This paper describes the S-CO2 power cycles for nuclear fission and fusion reactors.

  3. Study on the supercritical CO2 power cycles for landfill gas firing gas turbine bottoming cycle

    International Nuclear Information System (INIS)

    Kim, Min Seok; Ahn, Yoonhan; Kim, Beomjoo; Lee, Jeong Ik

    2016-01-01

    In this paper, a comparison of nine supercritical carbon dioxide (S-CO 2 ) bottoming power cycles in conjunction with a topping cycle of landfill gas (LFG) fired 5MWe gas turbine is presented. For the comparison purpose, a sensitivity study of the cycle design parameters for nine different cycles was conducted and each cycle thermodynamic performance is evaluated. In addition, the cycle performance evaluation dependency on the compressor inlet temperature variation is performed to investigate how S-CO 2 cycles sensitive to the heat sink temperature variation. Furthermore, the development of new S-CO 2 cycle layouts is reported and the suggested cycles' performances are compared to the existing cycle layouts. It was found that a recompression cycle is not suitable for the bottoming cycle application, but a partial heating cycle has relatively higher net produced work with a simple layout and small number of components. Although a dual heated and flow split cycle has the highest net produced work, it has disadvantages of having numerous components and complex process which requires more sophisticated operational strategies. This study identified that the recuperation process is much more important than the intercooling process to the S-CO 2 cycle design for increasing the thermal efficiency and the net produced work point of view. - Highlights: • Study of nine S-CO 2 power cycle layouts for a small scale landfill gas power generation application. • Development of new S-CO 2 cycle layouts. • Sensitivity analysis of S-CO 2 cycles to evaluate and compare nine cycles' performances.

  4. The Application of Supercritical CO{sub 2} Power Cycle to Various Nuclear Systems

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2015-10-15

    The main reason why the S-CO{sub 2} Brayton cycle has these advantages is that the compressor operates near the critical point of CO{sub 2} (30.98 .deg. C, 7.38MPa) to reduce the compression work significantly compared to the other Brayton cycles. In this paper, various applications of supercritical CO{sub 2} power cycle to nuclear systems will be presented and summarized. The S-CO{sub 2} cycle can achieve relatively high efficiency within the mild turbine inlet temperature range (450 - 850 .deg. C) compared with other power conversion systems. The main benefit of the S-CO{sub 2} cycle is the small size of the overall system and its application includes not only the next generation nuclear reactors but also conventional water-cooled reactors too. Various layouts were compared and the recompression cycle shows the best efficiency. The layout is suitable for application to advanced nuclear reactor systems. To evaluate the S-CO{sub 2} cycle performance, various countries constructed and demonstrated S-CO{sub 2} integral system test loops and similar research works are ongoing in Korea as well. However, to evaluate the commercial S-CO{sub 2} power systems, development of a large scale (> 10 MW) prototype S-CO{sub 2} system is necessary.

  5. Study on expansion power recovery in CO2 trans-critical cycle

    International Nuclear Information System (INIS)

    Tian Hua; Ma Yitai; Li Minxia; Wang Wei

    2010-01-01

    Due to the ozone depletion potential and global warming potential of CFCs and HCFCs, CO 2 is considered as most potential alternative refrigerant. However, there are serious throttle losses and low system efficiency to CO 2 trans-critical cycle because of its low critical temperature and high operating pressure. The aim of this paper is to design an expander to recover expansion power in CO 2 trans-critical cycle. The theoretical analysis and calculation show that 14-23% of input power of compressor can be recovered. A prototype of rolling piston expander is designed and manufactured and its test facility is established. The test facility consists of CO 2 trans-critical cycle, the expander, the chilling water system and the cooling water system. The experimental results show that the recovery ratio and expander efficiency are affected by rotational speed, inlet temperature and mass flow of expander. The highest recovery ratio can reach to 0.145, which means 14.5% of input power of compressor can be recovered. The expander efficiency can reach to 45%.

  6. Thermodynamic analysis and comparison between CO_2 transcritical power cycles and R245fa organic Rankine cycles for low grade heat to power energy conversion

    International Nuclear Information System (INIS)

    Li, L.; Ge, Y.T.; Luo, X.; Tassou, S.A.

    2016-01-01

    Highlights: • CO_2 is a promising working fluid to be applied in low-grade power generation systems. • Thermodynamic models of CO_2 transcritical power cycles (T-CO_2) and R245fa ORC were developed. • Energy and exergy analyses were carried out for T-CO_2 and R245fa ORC systems. • Optimal system designs are existed for both T-CO_2 and R245fa ORC systems. - Abstract: In this paper, a theoretical study is conducted to investigate and compare the performance of CO_2 transcritical power cycles (T-CO_2) and R245fa organic Rankine cycles (ORCs) using low-grade thermal energy to produce useful shaft or electrical power. Each power cycle consists of typical Rankine cycle components, such as a working fluid pump, gas generator or evaporator, turbine with electricity generator, air cooled condenser and recuperator (internal heat exchanger). The thermodynamic models of both cycles have been developed and are applied to calculate and compare the cycle thermal and exergy efficiencies at different operating conditions and control strategies. The simulation results show that the system performances for both cycles vary with different operating conditions. When the heat source (waste heat) temperature increases from 120 °C to 260 °C and heat sink (cooling air) temperature is reduced from 20 °C to 0 °C, both thermal efficiencies of R245fa ORC and T-CO_2 with recuperator can significantly increase. On the other hand, R245fa ORC and T-CO_2 exergy efficiencies increase with lower heat sink temperatures and generally decrease with higher heat source temperatures. In addition, with the same operating conditions and heat transfer assumptions, the thermal and exergy efficiencies of R245fa ORCs are both slightly higher than those of T-CO_2. However, the efficiencies of both cycles can be enhanced by installing a recuperator in each system at specified operating conditions. Ultimately, optimal operating states can be predicted, with particular focus on the working fluid expander

  7. Experimental and CFD Analysis of Printed Circuit Heat Exchanger for Supercritical CO{sub 2} Power Cycle Application

    Energy Technology Data Exchange (ETDEWEB)

    Baik, Seungjoon; Kim, Hyeon Tae; Kim, Seong Gu; Lee, Jekyoung; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2015-10-15

    The supercritical carbon dioxide (S-CO{sub 2}) power cycle has been suggested as an alternative for the SFR power generation system. First of all, relatively mild sodium-CO{sub 2} interaction can reduce the accident probability. Also the S-CO{sub 2} power conversion cycle can achieve high efficiency with SFR core thermal condition. Moreover, the S-CO{sub 2} power cycle can reduce cycle footprint due to high density of the working fluid. Recently, various compact heat exchangers have been studied for developing an optimal heat exchanger. In this paper, the printed circuit heat exchanger was selected for S-CO{sub 2} power cycle applications and was closely investigated experimentally and analytically. Recently, design and performance prediction of PCHE received attention due to its importance in high pressure power systems such as S-CO{sub 2} cycle. To evaluate a PCHE performance with CO{sub 2} to water, KAIST research team designed and tested a lab-scale PCHE. From the experimental data and CFD analysis, pressure drop and heat transfer correlations are obtained. For the CFD analysis, Ansys-CFX commercial code was utilized with RGP table implementation. In near future, the turbulence model sensitivity study will be followed.

  8. Thermodynamic modelling of a recompression CO_2 power cycle for low temperature waste heat recovery

    International Nuclear Information System (INIS)

    Banik, Shubham; Ray, Satyaki; De, Sudipta

    2016-01-01

    Highlights: • Thermodynamic model for recompression T-CO_2 is developed. • Energetic and exergetic analysis compared with S-CO_2 and Reg. Brayton cycle. • Maximum efficiency of 13.6% is obtained for T-CO_2 cycle. • Optimum recompression ratio of 0.48 is obtained for minimum irreversibility. • Reg. Brayton has better efficiency, T-CO_2 offers minimum irreversibility. - Abstract: Due to the rising prices of conventional fossil fuels, increasing the overall thermal efficiency of a power plant is essential. One way of doing this is waste heat recovery. This recovery is most difficult for low temperature waste heat, below 240 °C, which also covers majority of the waste heat source. Carbon dioxide, with its low critical temperature and pressure, offers an advantage over ozone-depleting refrigerants used in Organic Rankine Cycles (ORCs) and hence is most suitable for the purpose. This paper introduces parametric optimization of a transcritical carbon dioxide (T-CO_2) power cycle which recompresses part of the total mass flow of working fluid before entering the precooler, thereby showing potential for higher cycle efficiency. Thermodynamic model for a recompression T-CO_2 power cycle has been developed with waste heat source of 2000 kW and at a temperature of 200 °C. Results obtained from this model are analysed to estimate effects on energetic and exergetic performances of the power cycle with varying pressure and mass recompression ratio. Higher pressure ratio always improves thermodynamic performance of the cycle – both energetic and exergetic. Higher recompression ratio also increases exergetic efficiency of the cycle. However, it increases energy efficiency, only if precooler inlet temperature remains constant. Maximum thermal efficiency of the T-CO_2 cycle with a recompression ratio of 0.26 has been found to be 13.6%. To minimize total irreversibility of the cycle, an optimum ratio of 0.48 was found to be suitable.

  9. Parametric optimization design for supercritical CO2 power cycle using genetic algorithm and artificial neural network

    International Nuclear Information System (INIS)

    Wang Jiangfeng; Sun Zhixin; Dai Yiping; Ma Shaolin

    2010-01-01

    Supercritical CO 2 power cycle shows a high potential to recover low-grade waste heat due to its better temperature glide matching between heat source and working fluid in the heat recovery vapor generator (HRVG). Parametric analysis and exergy analysis are conducted to examine the effects of thermodynamic parameters on the cycle performance and exergy destruction in each component. The thermodynamic parameters of the supercritical CO 2 power cycle is optimized with exergy efficiency as an objective function by means of genetic algorithm (GA) under the given waste heat condition. An artificial neural network (ANN) with the multi-layer feed-forward network type and back-propagation training is used to achieve parametric optimization design rapidly. It is shown that the key thermodynamic parameters, such as turbine inlet pressure, turbine inlet temperature and environment temperature have significant effects on the performance of the supercritical CO 2 power cycle and exergy destruction in each component. It is also shown that the optimum thermodynamic parameters of supercritical CO 2 power cycle can be predicted with good accuracy using artificial neural network under variable waste heat conditions.

  10. Low CO2-emissions hybrid solar combined-cycle power system with methane membrane reforming

    International Nuclear Information System (INIS)

    Li, Yuanyuan; Zhang, Na; Cai, Ruixian

    2013-01-01

    Based on the principle of cascade utilization of multiple energy resources, a gas-steam combined cycle power system integrated with solar thermo-chemical fuel conversion and CO 2 capture has been proposed and analyzed. The collected solar heat at 550 °C drives the endothermic methane reforming and is converted to the produced syngas chemical exergy, and then released as high-temperature thermal energy via combustion for power generation, achieving its high-efficiency heat-power conversion. The reforming reaction is integrated with a hydrogen separation membrane, which continuously withdraws hydrogen from the reaction zone and enables nearly full methane conversion. The CO 2 enriched gas being concentrated in the retentate zone is collected and processed with pre-combustion decarbonization. The system is thermodynamically simulated using the ASPEN PLUS code. The results show that with 91% CO 2 captured, the specific CO 2 emission is 25 g/kWh. An exergy efficiency of 58% and thermal efficiency of 51.6% can be obtained. A fossil fuel saving ratio of 31.2% is achievable with a solar thermal share of 28.2%, and the net solar-to-electricity efficiency based on the gross solar heat incident on the collector is about 36.4% compared with the same gas-steam combined cycle system with an equal CO 2 removal ratio obtained by post-combustion decarbonization. - Highlights: ► A solar-assisted hybrid combined cycle power system has been proposed and analyzed. ► The system integrates power generation with solar-driven reforming and CO 2 capture. ► solar heat upgrading and high-efficiency heat-to-power conversion are achieved. ► membrane reforming enables high CH 4 conversion and pre-combustion CO 2 capture. ► The system thermodynamic performances have been investigated and compared

  11. Preliminary design of S-CO{sub 2} Brayton cycle for APR-1400 with power generation and desalination process

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Seong Jun; Lee, Won Woong; Jeong, Yong Hoon; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of); Yoon, Ho Joon [KUSTAR, Abu Dhabi (United Arab Emirates)

    2015-10-15

    This study was conducted to explore the capabilities of the S-CO{sub 2} Brayton cycle for a cogeneration system for APR-1400 application. Three concepts of the S-CO{sub 2} simple recuperated co-generation cycle were designed. A supercritical CO{sub 2} (S-CO{sub 2}) Brayton cycle is recently receiving significant attention as a promising power conversion system in wide range of energy applications due to its high efficiency and compact footprint. The main reason why the S-CO{sub 2} Brayton cycle has these advantages is that the compressor operates near the critical point of CO{sub 2} (30.98 .deg. C, 7.38MPa) to reduce the compression work significantly compared to the other Brayton cycles. In this study, the concept of replacing the entire steam cycle of APR-1400 with the S-CO{sub 2} Brayton cycle is evaluated. The power generation purpose S-CO{sub 2} Brayton cycles are redesigned to generate power and provide heat to the desalination system at the same time. The performance of these newly suggested cycles are evaluated in this paper. The target was to deliver 147MW heat to the desalination process. The thermal efficiencies of the three concepts are not significantly different, but the 3{sup rd} concept is relatively simpler than other cycles because only an additional heat exchanger is required. Although the 2{sup nd} concept is relatively complicated in comparison to other concepts, the temperatures at the inlet and outlet of the DHX are higher than that of the others. As shown in the results, the S-CO{sub 2} Brayton cycles are not easy to outperform the steam cycle with very simple layout and general design points under APR-1400 operating condition. However, this study shows that the S-CO{sub 2} Brayton cycles can be designed as a co-generation cycle while producing the target desalination heat with a simple configuration. In addition, it was also found that the S-CO{sub 2} Brayton cycle can achieve higher cycle thermal efficiency than the steam power cycle under

  12. Power by waste heat recovery from low temperature industrial flue gas by Organic Flash Cycle (OFC) and transcritical-CO_2 power cycle: A comparative study through combined thermodynamic and economic analysis

    International Nuclear Information System (INIS)

    Mondal, Subha; De, Sudipta

    2017-01-01

    Both Organic flash cycle and transcritical CO_2 power cycle (T-CO_2 power cycle) allow cooling of hot flue gas stream to an appreciably lower temperature due to the absence of pinch limitation. In the present study, a combined thermodynamic and economic comparison is conducted between a T-CO_2 power cycle and Organic flash cycles using R-245fa and R600 as the working fluids. It is observed that work output per kg of flue gas flow rate is slightly higher for the T-CO_2 power cycle if the flue gas is allowed to cool to the corresponding lowest possible temperature in the Heat Recovery Unit (HRU). It is also observed that with maximum possible cooling of flue gas, minimum bare module costs (BMCs) for each kW power output of OFCs are somewhat higher compared to that of T-CO_2 power cycle. Minimum BMCs for each kW output of OFCs can be reduced substantially by increasing terminal temperature difference at the low temperature end of the HRU. However, the increasing terminal temperature difference at the low temperature end of the HRU is having negligible effect on BMC ($/kW) of T-CO_2 power cycle. - Highlights: • Combined thermodynamic and economic analysis done for T-CO_2 power cycle and OFC. • With highest heat recovery, T-CO_2 cycle produces slightly higher work output/kg of flue gas. • With highest heat recovery, minimum bare module costs in $/kW is slightly higher for OFCs. • Work outputs/kg of flue gas of all cycles are almost equal for these minimum BMCs. • BMCs in $/kW for OFCs sharply decrease with larger flue gas exit temperature.

  13. Computational analysis of supercritical CO2 Brayton cycle power conversion system for fusion reactor

    International Nuclear Information System (INIS)

    Halimi, Burhanuddin; Suh, Kune Y.

    2012-01-01

    Highlights: ► Computational analysis of S-CO 2 Brayton cycle power conversion system. ► Validation of numerical model with literature data. ► Recompression S-CO 2 Brayton cycle thermal efficiency of 42.44%. ► Reheating concept to enhance the cycle thermal efficiency. ► Higher efficiency achieved by the proposed concept. - Abstract: The Optimized Supercritical Cycle Analysis (OSCA) code is being developed to analyze the design of a supercritical carbon dioxide (S-CO 2 ) driven Brayton cycle for a fusion reactor as part of the Modular Optimal Balance Integral System (MOBIS). This system is based on a recompression Brayton cycle. S-CO 2 is adopted as the working fluid for MOBIS because of its easy availability, high density and low chemical reactivity. The reheating concept is introduced to enhance the cycle thermal efficiency. The helium-cooled lithium lead model AB of DEMO fusion reactor is used as reference in this paper.

  14. Investigation of CO{sub 2} Recovery System Design in Supercritical Carbon Dioxide Power Cycle for Sodium-cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Seok; Jung, Hwa-Young; Ahn, Yoonhan; Cho, Seong Kuk; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2015-10-15

    These are mainly possible because the S-CO{sub 2} Brayton cycle has lower compressing work than other Brayton cycles due to its high density and low compressibility near the critical point. These attributes make easier to achieve higher turbine inlet temperature. Furthermore, the coolant chemistry control and component cooling systems are relatively simple for the S-CO{sub 2} cycle unlike the steam Rankine cycle, and therefore the total plant footprint can be greatly reduced further. However, certain amount of leakage flow is inevitable in the rotating turbo-machinery since the S-CO{sub 2} power cycle is a highly pressurized system. A computational model of critical flow in turbo-machinery seal is essential to predict the leakage flow and calculate the required total mass of working fluid in S-CO{sub 2} power system. Before designing a computational model of critical flow in turbo-machinery seal, this paper will identify what the issues are in predicting leakage flow and how these issues can be successfully addressed. Also, suitability of this solution in a large scale S-CO{sub 2} power cycle will be discussed, because this solution is for the small scale. S-CO{sub 2} power cycle has gained interest especially for the SFR application as an alternative to the conventional steam Rankine cycle, since S-CO{sub 2} power cycle can provide better performance and enhance safety. This paper discussed what the problem in leakage flow is and how to deal with this problem at present. High cavity pressure causing instability of gas foil bearing and large windage losses can be reduced by booster pump used to scavenge the gas in the rotor cavity. Also, labyrinth seals can be another good solution to decrease the rotor cavity pressure. Additionally, difference between large and small scale S-CO{sub 2} power cycle in turbo-machinery leakage is addressed. It is shown that optimization of CO{sub 2} recovery system design is more important to large scale S-CO{sub 2} power cycle. For

  15. Oxyfuel carbonation/calcination cycle for low cost CO2 capture in existing power plants

    International Nuclear Information System (INIS)

    Romeo, Luis M.; Abanades, J. Carlos; Escosa, Jesus M.; Pano, Jara; Gimenez, Antonio; Sanchez-Biezma, Andres; Ballesteros, Juan C.

    2008-01-01

    Postcombustion CO 2 capture is the best suitable capture technology for existing coal power plants. This paper focuses on an emerging technology that involves the separation of CO 2 using the reversible carbonation reaction of CaO to capture CO 2 from the flue gas, and the calcination of CaCO 3 to regenerate the sorbent and produce concentrated CO 2 for storage. We describe the application to this concept to an existing (with today's technology) power plant. The added capture system incorporates a new supercritical steam cycle to take advantage of the large amount of heat coming out from the high temperature capture process (oxyfired combustion of coal is needed in the CaCO 3 calciner). In these conditions, the capture system is able to generate additional power (26.7% efficiency respect to LHV coal input to the calciner after accounting for all the penalties in the overall system), without disturbing the steam cycle of the reference plant (that retains its 44.9 efficiency). A preliminary cost study of the overall system, using well established analogues in the open literature for the main components, yields capture cost around 16 Euro /ton CO 2 avoided and incremental cost of electricity of just over 1 Euro /MW h e

  16. Thermodynamic simulation of CO{sub 2} capture for an IGCC power plant using the calcium looping cycle

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y. [National Engineering Laboratory for Coal-Burning Pollutant Emission Reduction, Shandong University, Jinan (China); Zhao, C.; Ren, Q. [School of Energy and Environment, Southeast University, Nanjing (China)

    2011-06-15

    A CO{sub 2} capture process for an integrated gasification combined cycle (IGCC) power plant using the calcium looping cycle was proposed. The CO{sub 2} capture process using natural and modified limestone was simulated and investigated with the software package Aspen Plus. It incorporated a fresh feed of sorbent to compensate for the decay in CO{sub 2} capture activity during long-term cycles. The sorbent flow ratios have significant effect on the CO{sub 2} capture efficiency and net efficiency of the CO{sub 2} capture system. The IGCC power plant, using the modified limestone, exhibits higher CO{sub 2} capture efficiency than that using the natural limestone at the same sorbent flow ratios. The system net efficiency using the natural and modified limestones achieves 41.7% and 43.1%, respectively, at the CO{sub 2} capture efficiency of 90% without the effect of sulfation. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Performance comparison of two low-CO2 emission solar/methanol hybrid combined cycle power systems

    International Nuclear Information System (INIS)

    Li, Yuanyuan; Zhang, Na; Lior, Noam

    2015-01-01

    Highlights: • Two novel solar hybrid combined cycle systems have been proposed and analyzed. • The power systems integrate solar-driven thermo-chemical conversion and CO 2 capture. • Exergy efficiency of about 55% and specific CO 2 emissions of 34 g/kW h are predicted. • Systems CO 2 emissions are 36.8% lower compared to a combined cycle with CO 2 capture. • The fossil fuel demand is ∼30% lower with a solar share of ∼20%. - Abstract: Two novel hybrid combined cycle power systems that use solar heat and methanol, and integrate CO 2 capture, are proposed and analyzed, one based on solar-driven methanol decomposition and the other on solar-driven methanol reforming. The high methanol conversion rates at relatively low temperatures offer the advantage of using the solar heat at only 200–300 °C to drive the syngas production by endothermic methanol conversions and its conversion to chemical energy. Pre-combustion decarbonization is employed to produce CO 2 -free fuel from the fully converted syngas, which is then burned to produce heat at the high temperature for power generation in the proposed advanced combined cycle systems. To improve efficiency, the systems’ configurations were based on the principle of cascade use of multiple heat sources of different temperatures. The thermodynamic performance of the hybrid power systems at its design point is simulated and evaluated. The results show that the hybrid systems can attain an exergy efficiency of about 55%, and specific CO 2 emissions as low as 34 g/kW h. Compared to a gas/steam combined cycle with flue gas CO 2 capture, the proposed solar-assisted system CO 2 emissions are 36.8% lower, and a fossil fuel saving ratio of ∼30% is achievable with a solar thermal share of ∼20%. The system integration predicts high efficiency conversion of solar heat and low-energy-penalty CO 2 capture, with the additional advantage that solar heat is at relatively low temperature where its collection is cheaper and

  18. Parametrized overview of CO_2 power cycles for different operation conditions and configurations – An absolute and relative performance analysis

    International Nuclear Information System (INIS)

    Cardemil, José M.; Silva, Alexandre K. da

    2016-01-01

    Highlights: • Thermodynamic modeling of CO_2-based power cycles. • A multi-parameter analysis for different cycle configurations. • Performance comparison between CO_2 and four other fluids. • Detailed discussion considering optimized operational parameters (i.e., pressure, HX size). • Overview of the technical applicability of the CO_2. - Abstract: This thermodynamically based study focuses on the thermal performance of power cycles using CO_2 as the working fluid. The work considers numerous aspects that can influence the cycle's performance, such as the type of cycle (i.e., Rankine or Brayton), its configuration (i.e., with and without a recuperator), and different operational conditions (i.e., heat source temperature and the upper and lower operating pressures of the CO_2). To account for all possible scenarios, a thermodynamic routine was especially implemented and linked to a library that contained all the thermodynamics properties of CO_2. The results are mostly presented in terms of the absolute and relative 1st and 2nd Law efficiencies of CO_2 as well as the cycle's scale, here represented by the global conductance (UA) of the heat exchangers used within the cycle. For the relative performance assessment, four other working fluids, commonly used in energy conversion cycles, were considered (i.e., ethane, toluene, D4 siloxane and water). As expected, the absolute performance results indicate a strong dependence of the cycle's efficiencies on the operational conditions. As for the relative performance, the results suggest that while the CO_2's 1st Law efficiency might be lower than other fluids, its exergetic efficiency can be significantly higher. Furthermore, the calculations also indicate that the CO_2's needed global conductance is potentially lower than competing fluids (e.g., toluene) for certain operational conditions, which suggests that CO_2-based power plants can be more compact, since they might require smaller heat exchangers to produce

  19. Predicting the ultimate potential of natural gas SOFC power cycles with CO2 capture - Part B: Applications

    Science.gov (United States)

    Campanari, Stefano; Mastropasqua, Luca; Gazzani, Matteo; Chiesa, Paolo; Romano, Matteo C.

    2016-09-01

    An important advantage of solid oxide fuel cells (SOFC) as future systems for large scale power generation is the possibility of being efficiently integrated with processes for CO2 capture. Focusing on natural gas power generation, Part A of this work assessed the performances of advanced pressurised and atmospheric plant configurations (SOFC + GT and SOFC + ST, with fuel cell integration within a gas turbine or a steam turbine cycle) without CO2 separation. This Part B paper investigates such kind of power cycles when applied to CO2 capture, proposing two ultra-high efficiency plant configurations based on advanced intermediate-temperature SOFCs with internal reforming and low temperature CO2 separation process. The power plants are simulated at the 100 MW scale with a set of realistic assumptions about FC performances, main components and auxiliaries, and show the capability of exceeding 70% LHV efficiency with high CO2 capture (above 80%) and a low specific primary energy consumption for the CO2 avoided (1.1-2.4 MJ kg-1). Detailed results are presented in terms of energy and material balances, and a sensitivity analysis of plant performance is developed vs. FC voltage and fuel utilisation to investigate possible long-term improvements. Options for further improvement of the CO2 capture efficiency are also addressed.

  20. Life cycle assessment of coal-fired power plants and sensitivity analysis of CO2 emissions from power generation side

    Science.gov (United States)

    Yin, Libao; Liao, Yanfen; Zhou, Lianjie; Wang, Zhao; Ma, Xiaoqian

    2017-05-01

    The life cycle assessment and environmental impacts of a 1000MW coal-fired power plant were carried out in this paper. The results showed that the operation energy consumption and pollutant emission of the power plant are the highest in all sub-process, which accounts for 93.93% of the total energy consumption and 92.20% of the total emission. Compared to other pollutant emissions from the coal-fired power plant, CO2 reached up to 99.28%. Therefore, the control of CO2 emission from the coal-fired power plants was very important. Based on the BP neural network, the amount of CO2 emission from the generation side of coal-fired power plants was calculated via carbon balance method. The results showed that unit capacity, coal quality and unit operation load had great influence on the CO2 emission from coal-fired power plants in Guangdong Province. The use of high volatile and high heat value of coal also can reduce the CO2 emissions. What’s more, under higher operation load condition, the CO2 emissions of 1 kWh electric energy was less.

  1. Economical assessment of competitive enhanced limestones for CO2 capture cycles in power plants

    International Nuclear Information System (INIS)

    Romeo, Luis M.; Lara, Yolanda; Lisbona, Pilar; Martinez, Ana

    2009-01-01

    CO 2 capture systems based on the carbonation/calcination loop have gained rapid interest due to promising carbonator CO 2 capture efficiency, low sorbent cost and no flue gases treatment is required before entering the system. These features together result in a competitively low cost CO 2 capture system. Among the key variables that influence the performance of these systems and their integration with power plants, the carbonation conversion of the sorbent and the heat requirement at calciner are the most relevant. Both variables are mainly influenced by CaO/CO 2 ratio and make-up flow of solids. New sorbents are under development to reduce the decay of their carbonation conversion with cycles. The aim of this study is to assess the competitiveness of new limestones with enhanced sorption behaviour applied to carbonation/calcination cycle integrated with a power plant, compared to raw limestone. The existence of an upper limit for the maximum average capture capacity of CaO has been considered. Above this limit, improving sorbent capture capacity does not lead to the corresponding increase in capture efficiency and, thus, reduction of CO 2 avoided cost is not observed. Simulations calculate the maximum price for enhanced sorbents to achieve a reduction in CO 2 removal cost under different process conditions (solid circulation and make-up flow). The present study may be used as an assessment tool of new sorbents to understand what prices would be competitive compare with raw limestone in the CO 2 looping capture systems. (author)

  2. S-CO2 for efficient power generation with energy storage

    OpenAIRE

    Cerio Vera, Marta

    2016-01-01

    Supercritical CO2 (s-CO2) power cycle has gained interest for concentrating solar power (CSP) application in the last decade to overcome the current low efficiency and high costs of the plants. This cycle is a potential option to replace the steam Rankine cycle due to its higher efficiency, more compact turbomachinery and possibility of including heat storage and direct heating. The purpose of this project is to determine the suitability of integrating s-CO2 power cycle into CSP plants with e...

  3. MCFC power plant with CO{sub 2} separation

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, Noboru [Ishikawajima-Harima Heavy Industries Co., Ltd., Tokyo (Japan)

    1996-12-31

    Fuel cell power plant has been developed for many years with expectation of high system efficiency. In the meantime the gas turbine combined cycle has shown its considerable progress in improving system efficiency. Fuel cell power plant will no longer be attractive unless it exceeds the gas turbine combined cycle at least in the system efficiency. It is said CO{sub 2} separation could improve the efficiency of fuel cell power plant. IHI has developed the CO{sub 2} separator for fuel cell power plant. This study describes that the CO{sub 2} separator can increase the efficiency of the molten carbonate fuel cell (MCFC) power plant by 5% and the expected efficiency reaches 63 % in HHV basis.

  4. Supercritical CO2 Brayton power cycles for DEMO fusion reactor based on Helium Cooled Lithium Lead blanket

    International Nuclear Information System (INIS)

    Linares, José Ignacio; Herranz, Luis Enrique; Fernández, Iván; Cantizano, Alexis; Moratilla, Beatriz Yolanda

    2015-01-01

    Fusion energy is one of the most promising solutions to the world energy supply. This paper presents an exploratory analysis of the suitability of supercritical CO 2 Brayton power cycles (S-CO 2 ) for low-temperature divertor fusion reactors cooled by helium (as defined by EFDA). Integration of three thermal sources (i.e., blanket, divertor and vacuum vessel) has been studied through proposing and analyzing a number of alternative layouts, achieving an improvement on power production higher than 5% over the baseline case, which entails to a gross efficiency (before self-consumptions) higher than 42%. In spite of this achievement, the assessment of power consumption for the circulating heat transfer fluids results in a penalty of 20% in the electricity production. Once the most suitable layout has been selected an optimization process has been conducted to adjust the key parameters to balance performance and size, achieving an electrical efficiency (electricity without taking into account auxiliary consumptions due to operation of the fusion reactor) higher than 33% and a reduction in overall size of heat exchangers of 1/3. Some relevant conclusions can be drawn from the present work: the potential of S-CO 2 cycles as suitable converters of thermal energy to power in fusion reactors; the significance of a suitable integration of thermal sources to maximize power output; the high penalty of pumping power; and the convenience of identifying the key components of the layout as a way to optimize the whole cycle performance. - Highlights: • Supercritical CO 2 Brayton cycles have been proposed for BoP of HCLL fusion reactor. • Low temperature sources have been successfully integrated with high temperature ones. • Optimization of thermal sources integration improves 5% the electricity production. • Assessment of pumping power with sources and sink loops results on 20% of gross power. • Matching of key parameters has conducted to 1/3 of reduction in heat

  5. Thermodynamic Optimization of Supercritical CO{sub 2} Brayton Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Rhim, Dong-Ryul; Park, Sung-Ho; Kim, Su-Hyun; Yeom, Choong-Sub [Institute for Advanced Engineering, Yongin (Korea, Republic of)

    2015-05-15

    The supercritical CO{sub 2} Brayton cycle has been studied for nuclear applications, mainly for one of the alternative power conversion systems of the sodium cooled fast reactor, since 1960's. Although the supercritical CO{sub 2} Brayton cycle has not been expected to show higher efficiency at lower turbine inlet temperature over the conventional steam Rankine cycle, the higher density of supercritical CO{sub 2} like a liquid in the supercritical region could reduce turbo-machinery sizes, and the potential problem of sodium-water reaction with the sodium cooled fast reactor might be solved with the use of CO{sub 2} instead of water. The supercritical CO{sub 2} recompression Brayton cycle was proposed for the better thermodynamic efficiency than for the simple supercritical CO{sub 2} Brayton cycle. Thus this paper presents the efficiencies of the supercritical CO{sub 2} recompression Brayton cycle along with several decision variables for the thermodynamic optimization of the supercritical CO{sub 2} recompression Brayton cycle. The analytic results in this study show that the system efficiency reaches its maximum value at a compressor outlet pressure of 200 bars and a recycle fraction of 30 %, and the lower minimum temperature approach at the two heat exchangers shows higher system efficiency as expected.

  6. Cycle layout studies of S-CO2 cycle for the next generation nuclear system application

    International Nuclear Information System (INIS)

    Ahn, Yoonhan; Bae, Seong Jun; Kim, Minseok; Cho, Seong Kuk; Baik, Seungjoon; Lee, Jeong Ik; Cha, Jae Eun

    2014-01-01

    According to the second law of thermodynamics, the next generation nuclear reactor system efficiency can potentially be increased with higher operating temperature. Fig.1 shows several power conversion system efficiencies and heat sources with respect to the system top operating temperature. As shown in Fig.1, the steam Rankine and gas Brayton cycles have been considered as the major power conversion systems more than several decades. In the next generation reactor operating temperature region (450 - 900 .deg. C), the steam Rankine and gas Brayton cycles have limits due to material problems and low efficiency, respectively. Among the future power conversion systems, S-CO 2 cycle is receiving interests due to several benefits including high efficiency under the mild turbine inlet temperature range (450-650 .deg. C), compact turbomachinery and simple layout compared to the steam Rankine cycle. S-CO 2 cycle can show relatively high efficiency under the mild turbine inlet temperature range (450-600 .deg. C) compared to other power conversion systems. The recompression cycle shows the best efficiency among other layouts and it is suitable for the application to advanced nuclear reactor systems. As S-CO 2 cycle performance can vary depending on the layout configuration, further studies on the layouts are required to design a better performing cycle

  7. Optimizing an advanced hybrid of solar-assisted supercritical CO2 Brayton cycle: A vital transition for low-carbon power generation industry

    International Nuclear Information System (INIS)

    Milani, Dia; Luu, Minh Tri; McNaughton, Robbie; Abbas, Ali

    2017-01-01

    Highlights: • The layout of 14 demonstrative supercritical CO 2 closed Brayton cycles are analysed. • The key parameters of the “combined” cycle are sensitized and optimized. • The effect of thermal efficiency vs HX area on techno-economic nexus is highlighted. • The design of a matching solar heliostat field in direct configuration is revealed. • The water demand for hybrid vs water-only cooling scenarios are assessed. - Abstract: Current worldwide infrastructure of electrical power generation would mostly continue to rely on fossil-fuel but require a modest transition for the ultimate goal of decarbonizing power generation industry. By relying on those already established and carefully managed centrepiece power plants (PPs), we aim at filling the deficits of the current electrical networks with smaller, cleaner, and also more efficient PPs. In this context, we present a unique model for a small-scale decentralized solar-assisted supercritical CO 2 closed Brayton cycle (sCO 2 -CBC). Our model is based on the optimized values of three key performance indicators (KPIs); thermal efficiency, concentrated solar power (CSP) compatibility, and water demand for cooling. For a case-study of 10 MW e CSP-assisted sCO 2 -CBC power plant, our dynamic model shows a 52.7% thermal efficiency and 25.9% solar penetration and up to 80% of water saving in heat-rejection units. These KPIs show significant promise of the solar-assisted supercritical CO 2 power cycle for an imperative transformation in the power industry towards future sustainable electricity generation.

  8. Study on CO{sub 2} Recovery System Design in Supercritical CO{sub 2} Cycle for SFR Application

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Seok; Jung, Hwa-Young; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2016-10-15

    As a part of Sodium-cooled Fast Reactor (SFR) development in Korea, the supercritical CO{sub 2} (S-CO{sub 2}) Brayton cycle is considered as an alternative power conversion system to eliminate sodium-water reaction (SWR) when the current conventional steam Rankine cycle is utilized with SFR. The parasitic loss caused by the leakage flow should be minimized since this greatly influences the cycle efficiency. Thus, a simple model for estimating the critical flow in a turbo-machinery seal was developed to predict the leakage flow rate and calculate the required total mass of working fluid in a S-CO{sub 2} power system to minimize the parasitic loss. In this work, study on CO{sub 2} recovery system design was conducted by finding the suitable recovery point with the developed simple CO{sub 2} critical flow model and sensitivity analysis was performed on the power system performance with respect to multiple CO{sub 2} recovery process options. The study of a CO{sub 2} recovery system design was conducted to minimize the thermal efficiency losses caused by CO{sub 2} inventory recovery system. For the first step, the configuration of a seal was selected. A labyrinth seal has suitable features for the S-CO{sub 2} power cycle application. Then, thermal efficiency losses with different CO{sub 2} leak rate and recovery point were evaluated. To calculate the leak rate in turbo-machinery by using the developed CO{sub 2} critical flow model, the conditions of storage tank is set to be closer to the recovery point. After modifying the critical flow model appropriately, total mass flow rate of leakage flow was calculated. Finally, the CO{sub 2} recovery system design work was performed to minimize the loss of thermal efficiency. The suggested system is not only simple and intuitive but also has relatively very low additional work loss from the compressor than other considered systems. When each leak rate is set to the conventional leakage rate of 1 kg/s per seal, the minimum and

  9. Preliminary Design of S-CO2 Brayton Cycle for KAIST Micro Modular Reactor

    International Nuclear Information System (INIS)

    Kim, Seong Gu; Kim, Min Gil; Bae, Seong Jun; Lee, Jeong Ik

    2013-01-01

    This paper suggests a complete modular reactor with an innovative concept of reactor cooling by using a supercritical carbon dioxide directly. Authors propose the supercritical CO 2 Brayton cycle (S-CO 2 cycle) as a power conversion system to achieve small volume of power conversion unit (PCU) and to contain the core and PCU in one vessel for the full modularization. This study suggests a conceptual design of small modular reactor including PCU which is named as KAIST Micro Modular Reactor (MMR). As a part of ongoing research of conceptual design of KAIST MMR, preliminary design of power generation cycle was performed in this study. Since the targets of MMR are full modularization of a reactor system with S-CO 2 coolant, authors selected a simple recuperated S-CO 2 Brayton cycle as a power conversion system for KAIST MMR. The size of components of the S-CO 2 cycle is much smaller than existing helium Brayton cycle and steam Rankine cycle, and whole power conversion system can be contained with core and safety system in one containment vessel. From the investigation of the power conversion cycle, recompressing recuperated cycle showed higher efficiency than the simple recuperated cycle. However the volume of heat exchanger for recompressing cycle is too large so more space will be occupied by heat exchanger in the recompressing cycle than the simple recuperated cycle. Thus, authors consider that the simple recuperated cycle is more suitable for MMR. More research for the KAIST MMR will be followed in the future and detailed information of reactor core and safety system will be developed down the road. More refined cycle layout and design of turbomachinery and heat exchanger will be performed in the future study

  10. CONCEPTUAL DESIGN AND ECONOMICS OF THE ADVANCED CO2 HYBRID POWER CYCLE

    Energy Technology Data Exchange (ETDEWEB)

    A. Nehrozoglu

    2004-12-01

    Research has been conducted under United States Department of Energy Contract DEFC26-02NT41621 to analyze the feasibility of a new type of coal-fired plant for electric power generation. This new type of plant, called the Advanced CO{sub 2} Hybrid Power Plant, offers the promise of efficiencies nearing 36 percent, while concentrating CO{sub 2} for 100% sequestration. Other pollutants, such as SO{sub 2} and NOx, are sequestered along with the CO{sub 2} yielding a zero emissions coal plant. The CO{sub 2} Hybrid is a gas turbine-steam turbine combined cycle plant that uses CO{sub 2} as its working fluid to facilitate carbon sequestration. The key components of the plant are a cryogenic air separation unit (ASU), a pressurized circulating fluidized bed gasifier, a CO{sub 2} powered gas turbine, a circulating fluidized bed boiler, and a super-critical pressure steam turbine. The gasifier generates a syngas that fuels the gas turbine and a char residue that, together with coal, fuels a CFB boiler to power the supercritical pressure steam turbine. Both the gasifier and the CFB boiler use a mix of ASU oxygen and recycled boiler flue gas as their oxidant. The resulting CFB boiler flue gas is essentially a mixture of oxygen, carbon dioxide and water. Cooling the CFB flue gas to 80 deg. F condenses most of the moisture and leaves a CO{sub 2} rich stream containing 3%v oxygen. Approximately 30% of this flue gas stream is further cooled, dried, and compressed for pipeline transport to the sequestration site (the small amount of oxygen in this stream is released and recycled to the system when the CO{sub 2} is condensed after final compression and cooling). The remaining 70% of the flue gas stream is mixed with oxygen from the ASU and is ducted to the gas turbine compressor inlet. As a result, the gas turbine compresses a mixture of carbon dioxide (ca. 64%v) and oxygen (ca. 32.5%v) rather than air. This carbon dioxide rich mixture then becomes the gas turbine working fluid and

  11. CO2 emissions of nuclear power supply

    International Nuclear Information System (INIS)

    Wissel, S.; Mayer-Spohn, O.; Fahl, U.; Voss, A.

    2007-01-01

    Increasingly, supported by the recent reports of the IPCC (International Panel on Climate Change), political, social and scientific institutions call for the use of atomic energy for reducing CO2 emissions. In Germany, the discussion is highly controversial. A life-cycle balance of nuclear power shows that its CO2 emissions are much lower than those of other technologies, even if changes in the nuclear fuel cycle are taken into account. (orig.)

  12. CO2 cycle

    Science.gov (United States)

    Titus, Timothy N.; Byrne, Shane; Colaprete, Anthony; Forget, Francois; Michaels, Timothy I.; Prettyman, Thomas H.

    2017-01-01

    This chapter discusses the use of models, observations, and laboratory experiments to understand the cycling of CO2 between the atmosphere and seasonal Martian polar caps. This cycle is primarily controlled by the polar heat budget, and thus the emphasis here is on its components, including solar and infrared radiation, the effect of clouds (water- and CO2-ice), atmospheric transport, and subsurface heat conduction. There is a discussion about cap properties including growth and regression rates, albedos and emissivities, grain sizes and dust and/or water-ice contamination, and curious features like cold gas jets and araneiform (spider-shaped) terrain. The nature of the residual south polar cap is discussed as well as its long-term stability and ability to buffer atmospheric pressures. There is also a discussion of the consequences of the CO2 cycle as revealed by the non-condensable gas enrichment observed by Odyssey and modeled by various groups.

  13. Corrosion Behavior of Steels in Supercritical CO2 for Power Cycle Applications

    Energy Technology Data Exchange (ETDEWEB)

    Repukaiti, Richard [National Energy Technology Lab. (NETL), Albany, OR (United States); Oregon State Univ., Corvallis, OR (United States); Teeter, Lucas [National Energy Technology Lab. (NETL), Albany, OR (United States); Oregon State Univ., Corvallis, OR (United States); Ziomek-Moroz, Margaret [National Energy Technology Lab. (NETL), Albany, OR (United States); Dogan, Omer [National Energy Technology Lab. (NETL), Albany, OR (United States); Tucker, Julie [Oregon State Univ., Corvallis, OR (United States)

    2017-07-07

    In order to understand issues with corrosion of heat exchanger materials in direct supercritical carbon dioxide (sCO2) power cycles, a series of autoclave exposure experiments and electrochemical experiments have been conducted. Corrosion behaviors of 347H stainless steel and P91 martensitic-ferrtic steel in sCO2 environment have been compared. In autoclave exposure tests performed at 50°C- 245°C and 80 bar. Mass change measurements, surface characterization, and corrosion product analysis have been conducted to understand the corrosion behavior of steels in sCO2 containing H2O and O2. Electrochemical tests performed at room temperature and 50°C, a simulation environment of water condensation phase with dissolved CO2 was prepared to evaluate the corrosion resistance of materials. From both types of experiments, generally 347H showed higher corrosion resistance than P91.

  14. Transcritical CO2 power cycle – Effects of regenerative heating using turbine bleed gas at intermediate pressure

    International Nuclear Information System (INIS)

    Mondal, Subha; De, Sudipta

    2015-01-01

    For energy utilization from low temperature waste heat, CO 2 is a potential working fluid due to its lower critical temperature. In this work, assuming finite quantity of flue gas available at low temperature (200 °C), a thermodynamic model is developed for a transcritical CO 2 power cycle utilizing turbine bleed gas for regenerative heating. Analysis show that the cycle performance improves with higher value of bleed ratio. However, for a specified bleed pressure and bleed gas temperature at the regenerator exit, maximum practical value of bleed ratio may be fixed by considering the exponential growth of the regenerator size (specified by NTU (number of transfer unit)). Most significant observation is the existence of optimum bleed pressures corresponding to maximum 1st law efficiency or minimum cycle irreversibility for specified values of remaining cycle parameters. - Highlights: • Thermodynamic model for Transcritical CO 2 cycle with bleed gas are developed. • Effects of bleed ratio, pressure, and regenerator exit gas temperature are studied. • 1st and 2nd law efficiencies are estimated. • An optimum bleed pressure for maximum 1st and 2nd efficiencies is obtained. • Maximum value of 1st law efficiency is limited by regenerator size

  15. Application of optimal design methodologies in retrofitting natural gas combined cycle power plants with CO_2 capture

    International Nuclear Information System (INIS)

    Pan, Ming; Aziz, Farah; Li, Baohong; Perry, Simon; Zhang, Nan; Bulatov, Igor; Smith, Robin

    2016-01-01

    Highlights: • A new approach is proposed for retrofitting NGCC power plants with CO2 capture. • HTI techniques are developed for improving heat recovery in NGCC power plants. • EGR techniques are developed to increase the process overall energy efficiency. • The proposed methods are efficient for practical application. - Abstract: Around 21% of the world’s power production is based on natural gas. Energy production is considered to be the significant sources of carbon dioxide (CO_2) emissions. This has a significant effect on the global warming. Improving power plant efficiency and adding a CO_2 capture unit into power plants, have been suggested to be a promising countermeasure against global warming. This paper presents a new insight to the application of energy efficient technologies in retrofitting natural gas combined cycle (NGCC) power plants with CO_2 capture. High fidelity models of a 420 MW NGCC power plant and a CO_2 capture plant with CO_2 compression train have been built and integrated for 90% capture level. These models have been then validated by comparisons with practical operating data and literature results. The novelty of the paper is to propose optimal retrofitting strategies to minimize the efficiency penalty caused by integrating carbon capture units into the power plant, including (1) implementing heat transfer intensification techniques to increase energy saving in the heat recovery steam generator (HRSG) of the power plant; (2) extracting suitable steam from the HRSG to supply the heat required by the capture process, thus on external heat is purchased; (3) employing exhaust gas recirculation (EGR) to increase the overall energy efficiency of the integrated process, which can benefit both power plant (e.g. increasing power plant efficiency) and capture process (e.g. reducing heat demands). Compared with the base case without using any integrating and retrofitting strategies, the optimal solution based on the proposed approaches

  16. Exfoliation Propensity of Oxide Scale in Heat Exchangers Used for Supercritical CO2 Power Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Sabau, Adrian S [ORNL; Shingledecker, John P. [Electric Power Research Institute (EPRI); Kung, Steve [Electric Power Research Institute (EPRI); Wright, Ian G. [WrightHT, Inc.; Nash, Jim [Brayton Energy, LLC, Hampton, NH

    2016-01-01

    Supercritical CO2 (sCO2) Brayton cycle systems offer the possibility of improved efficiency in future fossil energy power generation plants operating at temperatures of 650 C and above. As there are few data on the oxidation/corrosion behavior of structural alloys in sCO2 at these temperatures, modeling to predict the propensity for oxide exfoliation is not well developed, thus hindering materials selection for these novel cycles. The ultimate goal of this effort is to provide needed data on scale exfoliation behavior in sCO2 for confident alloy selection. To date, a model developed by ORNL and EPRI for the exfoliation of oxide scales formed on boiler tubes in high-temperature, high-pressure steam has proven useful for managing exfoliation in conventional steam plants. A major input provided by the model is the ability to predict the likelihood of scale failure and loss based on understanding of the evolution of the oxide morphologies and the conditions that result in susceptibility to exfoliation. This paper describes initial steps taken to extend the existing model for exfoliation of steam-side oxide scales to sCO2 conditions. The main differences between high-temperature, high-pressure steam and sCO2 that impact the model involve (i) significant geometrical differences in the heat exchangers, ranging from standard pressurized tubes seen typically in steam-producing boilers to designs for sCO2 that employ variously-curved thin walls to create shaped flow paths for extended heat transfer area and small channel cross-sections to promote thermal convection and support pressure loads; (ii) changed operating characteristics with sCO2 due to the differences in physical and thermal properties compared to steam; and (iii) possible modification of the scale morphologies, hence properties that influence exfoliation behavior, due to reaction with carbon species from sCO2. The numerical simulations conducted were based on an assumed sCO2 operating schedule and several

  17. Preliminary Test of Friction disk type turbine for S-CO{sub 2} cycle application

    Energy Technology Data Exchange (ETDEWEB)

    Baik, Seungjoon; Kim, Hyeon Tae; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    Due to the relatively mild sodium-CO{sub 2} interaction, the S-CO{sub 2} Brayton cycle can reduce the accident consequence compared to the steam Rankine cycle. Also the S-CO{sub 2} power conversion cycle can achieve high efficiency for SFR core thermal condition. Moreover, the S-CO{sub 2} power cycle can reduce the total cycle footprint due to high density of the working fluid. However, the high pressure operating condition and low viscosity of the fluid cause difficulties in designing appropriate seals and multi-stage turbo machineries. To solve the problem for designing turbo machineries in a creative way, KAIST research team tested a friction disk type turbine concept for the S-CO{sub 2} cycle application. In this paper, the investigation of the Tesla turbine and preliminary test results with compressed air are covered. The KAIST research team investigated a friction disk type turbine, named as Tesla turbine, for the S-CO{sub 2} power cycle applications. Due to the robust design of the fiction disk type, the Tesla turbine technology can be utilized not only for S-CO{sub 2} turbo machinery but also for the multi-phase or sludge flow turbo machinery. The preliminary test of lab-scale Tesla turbine with compressed air was conducted. The high pressure vessel was manufactured for the S-CO{sub 2} operating condition. The test will be concentrated on the turbine efficiency measurement under various conditions and development of the design methodology.

  18. Modeling and sizing of the heat exchangers of a new supercritical CO2 Brayton power cycle for energy conversion for fusion reactors

    International Nuclear Information System (INIS)

    Serrano, I.P.; Cantizano, A.; Linares, J.I.; Moratilla, B.Y.

    2014-01-01

    Highlights: •We propose a procedure to model the heat exchangers of a S-CO2 Brayton power cycle. •Discretization in sub-heat exchangers is performed due to complex behavior of CO 2 . •Different correlations have been tested, verifying them with CFD when necessary. •Obtained sizes are agree with usual values of printed circuit heat exchangers. -- Abstract: TECNO F US is a research program financed by the Spanish Government to develop technologies related to a dual-coolant (He/Pb–Li) breeding blanket design concept including the auxiliary systems for a future power reactor (DEMO). One of the main issues of this program is the optimization of heat recovery from the reactor and its conversion into electrical power. This paper is focused on the methodology employed for the design and sizing of all the heat exchangers of the supercritical CO 2 Brayton power cycle (S-CO2) proposed by the authors. Due to the large pressure difference between the fluids, and also to their compactness, Printed Circuit Heat Exchangers (PCHE) are suggested in literature for these type of cycles. Because of the complex behavior of CO 2 , their design is performed by a numerical discretization into sub-heat exchangers, thus a higher precision is reached when the thermal properties of the fluids vary along the heat exchanger. Different empirical correlations for the pressure drop and the Nusselt number have been coupled and assessed. The design of the precooler (PC) and the low temperature recuperator (LTR) is also verified by simulations using CFD because of the near-critical behavior of CO 2 . The size of all of the heat exchangers of the cycle have been assessed

  19. Predicting the ultimate potential of natural gas SOFC power cycles with CO2 capture - Part A: Methodology and reference cases

    Science.gov (United States)

    Campanari, Stefano; Mastropasqua, Luca; Gazzani, Matteo; Chiesa, Paolo; Romano, Matteo C.

    2016-08-01

    Driven by the search for the highest theoretical efficiency, in the latest years several studies investigated the integration of high temperature fuel cells in natural gas fired power plants, where fuel cells are integrated with simple or modified Brayton cycles and/or with additional bottoming cycles, and CO2 can be separated via chemical or physical separation, oxy-combustion and cryogenic methods. Focusing on Solid Oxide Fuel Cells (SOFC) and following a comprehensive review and analysis of possible plant configurations, this work investigates their theoretical potential efficiency and proposes two ultra-high efficiency plant configurations based on advanced intermediate-temperature SOFCs integrated with a steam turbine or gas turbine cycle. The SOFC works at atmospheric or pressurized conditions and the resulting power plant exceeds 78% LHV efficiency without CO2 capture (as discussed in part A of the work) and 70% LHV efficiency with substantial CO2 capture (part B). The power plants are simulated at the 100 MW scale with a complete set of realistic assumptions about fuel cell (FC) performance, plant components and auxiliaries, presenting detailed energy and material balances together with a second law analysis.

  20. Preliminary Studies of Two-Phase Reactive Process of Sodium-CO2 in S-CO2 Power Conversion Cycle Coupled to SFR System

    International Nuclear Information System (INIS)

    Jung, Hwa Young; Ahn, Yoon Han; Lee, You Ho; Lee, Jeong Ik

    2013-01-01

    As a competing alternative to the steam Rankine cycle, the supercritical CO 2 (S-CO 2 ) Brayton cycle has been highlighted due to its high thermal efficiency, compact turbomachinery and heat exchangers sizes, and the reduced risk of SWRs. While the reduced risk of an SWR is considered as the one of most pronounced benefits of S-CO 2 Brayton cycle, there is still an interaction problem between liquid sodium and CO 2 . Although the chemical interaction between liquid sodium and CO 2 demonstrates less serious potential risks than those of a SWR, the Na/CO 2 interaction should be understood to evaluate safety and reliability of Intermediate Heat eXchanger (IHX). A noticeable characteristic of the reaction environment is that there is a large pressure difference between the liquid sodium and CO 2 side by about 1 and 200 bar, respectively. This would imply that the presence of a micro-crack in a heat exchanger tube will cause a high-pressure leak of CO 2 into liquid sodium side. Although the Na/CO 2 interaction may play an important role in the safety of the SFR reactor system, there has not yet been any research on understanding Na/CO 2 reaction by leakage through IHX. For this problem, the Korea Advanced Institute of Science and Technology (KAIST) research team is studying the mechanism of CO 2 leakage and Na/CO 2 interaction in more details. The KAIST research team developed the MATLAB code, KAIST H XD, which can be used to design and evaluate performance of a heat exchanger of an S-CO 2 cycle. The size of heat exchanger and the amount of CO 2 in the cycle are calculated from the KAIST H XD code to estimate the amount of reaction products in Na/CO 2 interaction as well as liquid sodium

  1. Application of S-CO_2 Cycle for Small Modular Reactor coupled with Desalination System

    International Nuclear Information System (INIS)

    Lee, Won Woong; Bae, Seong Jun; Lee, Jeong Ik

    2016-01-01

    The Korean small modular reactor, SMART (System-integrated Modular Advanced ReacTor, 100MWe), is designed to achieve enhanced safety and improved economics through reliable passive safety systems, a system simplification and component modularization. SMART can generate electricity and provide water by seawater desalination. However, due to the desalination aspect of SMART, the total amount of net electricity generation is decreased from 100MWe to 90MWe. The authors suggest in this presentation that the reduction of electricity generation can be replenished by applying S-CO_2 power cycle technology. The S-CO_2 Brayton cycle, which is recently receiving significant attention as the next generation power conversion system, has some benefits such as high cycle efficiency, simple configuration, compactness and so on. In this study, the cycle performance analysis of the S-CO_2 cycles for SMART with desalination system is conducted. The simple recuperated S-CO_2 cycle is revised for coupling with desalination system. The three revised layout are proposed for the cycle performance comparison. In this results of the 3rd revised layout, the cycle efficiency reached 37.8%, which is higher than the efficiency of current SMART with the conventional power conversion system 30%

  2. Review of supercritical CO{sub 2} power cycle technology and current status of research and development

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Yoon Han; Bae, Seong Jun; Kim, Min Seok; Cho, Seong Kuk; Baik, Seung Joon; Lee, Jeong Ik [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Cha, Jae Eun [Fast Reactor Technology Development Division, Korean Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The supercritical CO{sub 2} (S-CO{sub 2}) Brayton cycle has recently been gaining a lot of attention for application to next generation nuclear reactors. The advantages of the S-CO-2 cycle are high efficiency in the mild turbine inlet temperature region and a small physical footprint with a simple layout, compact turbomachinery, and heat exchangers. Several heat sources including nuclear, fossil fuel, waste heat, and renewable heat sources such as solar thermal or fuel cells are potential application areas of the S-CO-2 cycle. In this paper, the current development progress of the S-CO-2 cycle is introduced. Moreover, a quick comparison of various S-CO{sub 2} layouts is presented in terms of cycle performance.

  3. Supercritical CO2 Brayton Cycle Energy Conversion System Coupled with SFR

    International Nuclear Information System (INIS)

    Cha, Jae Eun; Kim, S. O.; Seong, S. H.; Eoh, J. H.; Lee, T. H.; Choi, S. K.; Han, J. W.; Bae, S. W.

    2008-12-01

    This report contains the description of the S-CO 2 Brayton cycle coupled to KALIMER-600 as an alternative energy conversion system. For a system development, a computer code was developed to calculate heat balance of normal operation condition. Based on the computer code, the S-CO 2 Brayton cycle energy conversion system was constructed for the KALIMER-600. Computer codes were developed to analysis for the S-CO 2 turbomachinery. Based on the design codes, the design parameters were prepared to configure the KALIMER-600 S-CO 2 turbomachinery models. A one-dimensional analysis computer code was developed to evaluate the performance of the previous PCHE heat exchangers and a design data for the typical type PCHE was produced. In parallel with the PCHE-type heat exchanger design, an airfoil shape fin PCHE heat exchanger was newly designed. The new design concept was evaluated by three-dimensional CFD analyses. Possible control schemes for power control in the KALIMER-600 S-CO 2 Brayton cycle were investigated by using the MARS code. The MMS-LMR code was also developed to analyze the transient phenomena in a SFR with a supercritical CO 2 Brayton cycle to develop the control logic. Simple power reduction and recovery event was selected and analyzed for the transient calculation. For the evaluation of Na-CO 2 boundary failure event, a computer was developed to simulate the complex thermodynamic behaviors coupled with the chemical reaction between liquid sodium and CO 2 gas. The long term behavior of a Na-CO 2 boundary failure event and its consequences which lead to a system pressure transient were evaluated

  4. Studies of S-CO{sub 2} Power Plant Pipe Design

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Minseok; Ahn, Yoonhan; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    Further development of nuclear energy is required to address the global warming issue while overcoming the difficulty of meeting the constantly growing demand of energy. As the nuclear energy does not only reduce the carbon dioxide emission but also attain sufficient and stable electricity supply, this is considered as one of the most clean and sustainable energy sources. The Sodium-cooled Fast Reactor (SFR) is a strong candidate among the next generation nuclear reactors. However, current SFR design may face difficulty in public acceptance due to the potential hazard from sodium-water reaction (SWR) when the current conventional steam Rankine cycle is utilized as a power conversion system for SFR. In order to eliminate SWR, the Supercritical CO{sub 2} (S-CO{sub 2}) cycle has been proposed. Although many S-CO{sub 2} cycle concepts are being suggested by many research organizations, pipe selection criteria for S-CO{sub 2} cycle are one of the areas that are not clearly established. As one of the most important parts of the plant design is economical fluid transfer, this paper will discuss how to select a suitable pipe for the S-CO{sub 2} power plant compared to steam Rankine cycle. The main advantages of S-CO{sub 2} cycle are: prevention of no SWR by changing the working fluid, relatively high efficiency with 450∼750 .deg. C turbine inlet temperature, physically compact size. Additional study for larger system such as 300MW class system in MIT report will be conducted. From the preliminary estimation when the S-CO{sub 2} system becomes large than the pipe diameter may exceed the current ASME standard. This means that more innovative approach will be needed for the S-CO{sub 2} pipe design. To economically design the pipe of S-CO{sub 2} recompressing cycle, optimal flow velocity for S-CO{sub 2} that can be obtained through the process engineering should exist. Although the Ronald W. Capps equation offers an optimal flow velocity while considering safety, capital

  5. Enhanced arrangement for recuperators in supercritical CO2 Brayton power cycle for energy conversion in fusion reactors

    International Nuclear Information System (INIS)

    Serrano, I.P.; Linares, J.I.; Cantizano, A.; Moratilla, B.Y.

    2014-01-01

    Highlights: •We propose an enhanced power conversion system layout for a Model C fusion reactor. •Proposed layout is based on a modified recompression supercritical CO 2 Brayton cycle. •New arrangement in recuperators regards to classical cycle is used. •High efficiency is achieved, comparable with the best obtained in complex solutions. -- Abstract: A domestic research program called TECNO F US was launched in Spain in 2009 to support technological developments related to a dual coolant breeding blanket concept for fusion reactors. This concept of blanket uses Helium (300 °C/400 °C) to cool part of it and a liquid metal (480 °C/700 °C) to cool the rest; it also includes high temperature (700 °C/800 °C) and medium temperature (566 °C/700 °C) Helium cooling circuits for divertor. This paper proposes a new layout of the classical recompression supercritical CO 2 Brayton cycle which replaces one of the recuperators (the one with the highest temperature) by another which by-passes the low temperature blanket source. This arrangement allows reaching high turbine inlet temperatures (around 600 °C) with medium pressures (around 225 bar) and achieving high cycle efficiencies (close to 46.5%). So, the proposed cycle reveals as a promising design because it integrates all the available thermal sources in a compact layout achieving high efficiencies with the usual parameters prescribed in classical recompression supercritical CO 2 Brayton cycles

  6. A Conceptual Study of Using an Isothermal Compressor on a Supercritical CO2 Cycle for Various Nuclear Applications

    International Nuclear Information System (INIS)

    Heo, Jin Young; Lee, Jeong Ik

    2017-01-01

    In order to accelerate the deployment of cleaner and safer energy sources, further development of such advanced nuclear power systems is necessary. By aiming to have higher efficiency, lower costs, and reduced system size, next-generation nuclear reactors can have greater advantages which will justify their adoption. Many research efforts focus on these objectives to also propose new concepts and technologies to improve the present state of the art. To maximize the benefits of advanced reactor designs, the supercritical CO 2 (S-CO 2 ) power cycle can be adopted to enhance the performance of the power conversion systems. The potential of replacing the conventional power block with the S-CO 2 power cycle can increase the cycle efficiency and also reduce its overall system size. The potential of using the S-CO 2 power cycles in advanced nuclear reactors can be further improved by adopting an isothermal compressor to the cycle layout. This paper attempts to improve the cycle layout by replacing the conventional compressor with an isothermal compressor, of which its potential in the S-CO 2 power cycle is conceptually being evaluated. An isothermal compressor minimizes compression work and further reduces the system size by having smaller heat exchanger requirements. The study includes cycle optimization maximizing cycle efficiency with respect to different cycle design parameters. The S-CO 2 iso-Brayton cycle layouts have been effective in improving the cycle efficiencies of the next-generation nuclear reactors. By using the isothermal compressor, the net efficiency can be improved by 8% points for the simple recuperated cycle layout, and 5% points for the recompression cycle layout. It is also noted that the estimated UA values required for the iso-Brayton cycle layouts are almost the same or less compared to those of the reference cycle layouts.

  7. Modeling and sizing of the heat exchangers of a new supercritical CO{sub 2} Brayton power cycle for energy conversion for fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, I.P.; Cantizano, A.; Linares, J.I., E-mail: linares@upcomillas.es; Moratilla, B.Y.

    2014-10-15

    Highlights: •We propose a procedure to model the heat exchangers of a S-CO2 Brayton power cycle. •Discretization in sub-heat exchangers is performed due to complex behavior of CO{sub 2}. •Different correlations have been tested, verifying them with CFD when necessary. •Obtained sizes are agree with usual values of printed circuit heat exchangers. -- Abstract: TECNO{sub F}US is a research program financed by the Spanish Government to develop technologies related to a dual-coolant (He/Pb–Li) breeding blanket design concept including the auxiliary systems for a future power reactor (DEMO). One of the main issues of this program is the optimization of heat recovery from the reactor and its conversion into electrical power. This paper is focused on the methodology employed for the design and sizing of all the heat exchangers of the supercritical CO{sub 2} Brayton power cycle (S-CO2) proposed by the authors. Due to the large pressure difference between the fluids, and also to their compactness, Printed Circuit Heat Exchangers (PCHE) are suggested in literature for these type of cycles. Because of the complex behavior of CO{sub 2}, their design is performed by a numerical discretization into sub-heat exchangers, thus a higher precision is reached when the thermal properties of the fluids vary along the heat exchanger. Different empirical correlations for the pressure drop and the Nusselt number have been coupled and assessed. The design of the precooler (PC) and the low temperature recuperator (LTR) is also verified by simulations using CFD because of the near-critical behavior of CO{sub 2}. The size of all of the heat exchangers of the cycle have been assessed.

  8. Exergoeconomic analysis of utilizing the transcritical CO_2 cycle and the ORC for a recompression supercritical CO_2 cycle waste heat recovery: A comparative study

    International Nuclear Information System (INIS)

    Wang, Xurong; Dai, Yiping

    2016-01-01

    Highlights: • An exergoeconomic analysis is performed for sCO_2/tCO_2 cycle. • Performance of the sCO_2/tCO_2 cycle and sCO_2/ORC cycle are presented and compared. • The sCO_2/tCO_2 cycle performs better than the sCO_2/ORC cycle at lower PRc. • The sCO_2/tCO_2 cycle has comparable total product unit cost with the sCO_2/ORC cycle. - Abstract: Two combined cogeneration cycles are examined in which the waste heat from a recompression supercritical CO_2 Brayton cycle (sCO_2) is recovered by either a transcritical CO_2 cycle (tCO_2) or an Organic Rankine Cycle (ORC) for generating electricity. An exergoeconomic analysis is performed for sCO_2/tCO_2 cycle performance and its comparison to the sCO_2/ORC cycle. The following organic fluids are considered as the working fluids in the ORC: R123, R245fa, toluene, isobutane, isopentane and cyclohexane. Thermodynamic and exergoeconomic models are developed for the cycles on the basis of mass and energy conservations, exergy balance and exergy cost equations. Parametric investigations are conducted to evaluate the influence of decision variables on the performance of sCO_2/tCO_2 and sCO_2/ORC cycles. The performance of these cycles is optimized and then compared. The results show that the sCO_2/tCO_2 cycle is preferable and performs better than the sCO_2/ORC cycle at lower PRc. When the sCO_2 cycle operates at a cycle maximum pressure of around 20 MPa (∼2.8 of PRc), the tCO_2 cycle is preferable to be integrated with the recompression sCO_2 cycle considering the off-design conditions. Moreover, contrary to the sCO_2/ORC system, a higher tCO_2 turbine inlet temperature improves exergoeconomic performance of the sCO_2/tCO_2 cycle. The thermodynamic optimization study reveals that the sCO_2/tCO_2 cycle has comparable second law efficiency with the sCO_2/ORC cycle. When the optimization is conducted based on the exergoeconomics, the total product unit cost of the sCO_2/ORC is slightly lower than that of the sCO_2/tCO_2

  9. A Conceptual Study of Using an Isothermal Compressor on a Supercritical CO_2 Brayton Cycle for SMART Application

    International Nuclear Information System (INIS)

    Heo, Jin Young; Lee, Jeong Ik; Ahn, Yoonhan

    2016-01-01

    To maximize the benefits of modularization, the supercritical CO_2 (S-CO_2) power cycle can replace the conventional steam Rankine cycle to increase the cycle efficiency and reduce its system size. Previous works have been conducted to evaluate potential advantages of applying the S-CO_2 cycle to SMRs, specifically to SMART (System-integrated Modular Advanced Reactor) which is an integral SMR developed by KAERI (Korea Atomic Energy Institute). One of the optimized S-CO_2 cycle layouts is the recompressing Brayton cycle. This paper attempts to improve the cycle layout by replacing the conventional compressor with an isothermal compressor, of which its potential in the S-CO_2 power cycle is conceptually being evaluated. The SMR applications, for which SMART reactor has been represented, can take advantage of the currently developing S-CO_2 cycle greatly by the reduction of size. By introducing the isothermal compressor, the cycle layout considered in has been further improved by increasing the cycle net efficiency by around 0.5%

  10. Preliminary study of Friction disk type turbine for S-CO_2 cycle application (2016 Autumn Meeting of the KNS)

    International Nuclear Information System (INIS)

    Baik, Seungjoon; Heo, Jin Young; Kwon, Jinsu; Lee, Jeong Ik

    2016-01-01

    Among the next generation reactors, a sodium-cooled fast reactor (SFR) with the supercritical carbon dioxide (S-CO_2) Brayton cycle has been suggested as the advanced energy solution. The S-CO_2 power conversion system can achieve high efficiency with the SFR core thermal condition (450-550℃) and also can reduce the total cycle footprint due to high density of the working fluid. Moreover, the S-CO_2 power cycle can reduce the accident consequence compared to the steam Rankine cycle due to the mild sodium-CO_2 interaction. The S-CO_2 power cycle has different characteristic compare to the conventional steam Rankine cycle or gas Brayton cycle. For the turbine section, the expansion ratio is much smaller than the other cycles. Thus, different type of turbine should be evaluated for the advanced S-CO_2 technology and the KAIST research team considered a friction disk type turbine (Tesla turbine) concept for the S-CO_2 cycle applications. In this paper, the test result and analysis of a lab-scale Tesla turbine in the KAIST S-CO_2 experimental facility (S-CO_2PE) are briefly discussed. The KAIST research team investigated a friction disk type turbine, named as Tesla turbine, for the S-CO_2 power cycle applications. The preliminary test of a lab-scale Tesla turbine was conducted with compressed air. The generator, nozzle angle and bearing performances are tested. With the best performing nozzle angle and bearing, the Tesla turbine was tested under various S-CO_2 conditions. As a result, the S-CO_2PE facility generated electricity (0.5-5W). The isentropic efficiency was relatively low (0.8-1.3%). It seemed that, the authors need further study to understand the main mechanism and maximize the efficiency. After developing the design methodology, the design optimization will be conducted to show the applicability of the friction disk type turbine for the S-CO_2 power cycle

  11. Application of S-CO{sub 2} Cycle for Small Modular Reactor coupled with Desalination System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Woong; Bae, Seong Jun; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2016-10-15

    The Korean small modular reactor, SMART (System-integrated Modular Advanced ReacTor, 100MWe), is designed to achieve enhanced safety and improved economics through reliable passive safety systems, a system simplification and component modularization. SMART can generate electricity and provide water by seawater desalination. However, due to the desalination aspect of SMART, the total amount of net electricity generation is decreased from 100MWe to 90MWe. The authors suggest in this presentation that the reduction of electricity generation can be replenished by applying S-CO{sub 2} power cycle technology. The S-CO{sub 2} Brayton cycle, which is recently receiving significant attention as the next generation power conversion system, has some benefits such as high cycle efficiency, simple configuration, compactness and so on. In this study, the cycle performance analysis of the S-CO{sub 2} cycles for SMART with desalination system is conducted. The simple recuperated S-CO{sub 2} cycle is revised for coupling with desalination system. The three revised layout are proposed for the cycle performance comparison. In this results of the 3rd revised layout, the cycle efficiency reached 37.8%, which is higher than the efficiency of current SMART with the conventional power conversion system 30%.

  12. Study of steam, helium and supercritical CO2 turbine power generations in prototype fusion power reactor

    International Nuclear Information System (INIS)

    Ishiyama, Shintaro; Muto, Yasushi; Kato, Yasuyoshi; Nishio, Satoshi; Hayashi, Takumi; Nomoto, Yasunobu

    2008-01-01

    Power generation systems such as steam turbine cycle, helium turbine cycle and supercritical CO 2 (S-CO 2 ) turbine cycle are examined for the prototype nuclear fusion reactor. Their achievable cycle thermal efficiencies are revealed to be 40%, 34% and 42% levels for the heat source outlet coolant temperature of 480degC, respectively, if no other restriction is imposed. In the current technology, however, low temperature divertor heat source is included. In this actual case, the steam turbine system and the S-CO 2 turbine system were compared in the light of cycle efficiency and plant cost. The values of cycle efficiency were 37.7% and 36.4% for the steam cycle and S-CO 2 cycle, respectively. The construction cost was estimated by means of component volume. The volume became 16,590 m 3 and 7240 m 3 for the steam turbine system and S-CO 2 turbine system, respectively. In addition, separation of permeated tritium from the coolant is much easier in S-CO 2 than in H 2 O. Therefore, the S-CO 2 turbine system is recommended to the fusion reactor system than the steam turbine system. (author)

  13. Enhanced arrangement for recuperators in supercritical CO{sub 2} Brayton power cycle for energy conversion in fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, I.P.; Linares, J.I., E-mail: linares@dim.icai.upcomillas.es; Cantizano, A.; Moratilla, B.Y.

    2014-10-15

    Highlights: •We propose an enhanced power conversion system layout for a Model C fusion reactor. •Proposed layout is based on a modified recompression supercritical CO{sub 2} Brayton cycle. •New arrangement in recuperators regards to classical cycle is used. •High efficiency is achieved, comparable with the best obtained in complex solutions. -- Abstract: A domestic research program called TECNO{sub F}US was launched in Spain in 2009 to support technological developments related to a dual coolant breeding blanket concept for fusion reactors. This concept of blanket uses Helium (300 °C/400 °C) to cool part of it and a liquid metal (480 °C/700 °C) to cool the rest; it also includes high temperature (700 °C/800 °C) and medium temperature (566 °C/700 °C) Helium cooling circuits for divertor. This paper proposes a new layout of the classical recompression supercritical CO{sub 2} Brayton cycle which replaces one of the recuperators (the one with the highest temperature) by another which by-passes the low temperature blanket source. This arrangement allows reaching high turbine inlet temperatures (around 600 °C) with medium pressures (around 225 bar) and achieving high cycle efficiencies (close to 46.5%). So, the proposed cycle reveals as a promising design because it integrates all the available thermal sources in a compact layout achieving high efficiencies with the usual parameters prescribed in classical recompression supercritical CO{sub 2} Brayton cycles.

  14. Supercritical CO2 Brayton power cycles for DEMO (demonstration power plant) fusion reactor based on dual coolant lithium lead blanket

    International Nuclear Information System (INIS)

    Linares, José Ignacio; Cantizano, Alexis; Moratilla, Beatriz Yolanda; Martín-Palacios, Víctor; Batet, Lluis

    2016-01-01

    This paper presents an exploratory analysis of the suitability of supercritical CO 2 Brayton power cycles as alternative energy conversion systems for a future fusion reactor based on a DCLL (dual coolant lithium-lead) blanket, as prescribed by EUROfusion. The main issue dealt is the optimization of the integration of the different thermal sources with the power cycle in order to achieve the highest electricity production. The analysis includes the assessment of the pumping consumption in the heating and cooling loops, taking into account additional considerations as control issues and integration of thermal energy storage systems. An exergy analysis has been performed in order to understand the behavior of each layout. Up to ten scenarios have been analyzed assessing different locations for thermal sources heat exchangers. Neglecting the worst four scenarios, it is observed less than 2% of variation among the other six ones. One of the best six scenarios clearly stands out over the others due to the location of the thermal sources in a unique island, being this scenario compatible with the control criteria. In this proposal 34.6% of electric efficiency (before the self-consumptions of the reactor but including pumping consumptions and generator efficiency) is achieved. - Highlights: • Supercritical CO 2 Brayton cycles have been proposed for BoP of DCLL fusion reactor. • Integration of different available thermal sources has been analyzed considering ten scenarios. • Neglecting the four worst scenarios the electricity production varies less than 2%. • Control and energy storage integration issues have been considered in the analysis. • Discarding the vacuum vessel and joining the other sources in an island is proposed.

  15. Hollow Co2P nanoflowers organized by nanorods for ultralong cycle-life supercapacitors

    KAUST Repository

    Cheng, Ming

    2017-08-24

    Hollow Co2P nanoflowers (Co2P HNF) are successfully prepared via a one-step, template-free method. Microstructure analysis reveals that Co2P HNF is assembled by nanorods, possesses abundant mesopores and a amorphous carbon shell. Density functional theory calculation and electrochemical measurements demonstrate the high electrical conductivity of Co2P. Benefiting from the unique nanostructures, when employed as electrode material for supercapacitors, Co2P HNF exhibits a high specific capacitance, an outstanding rate capability, and an ultralong cycle stability. Furthermore,. the constructed Co2P HNF//AC ASC yields a high energy density of 30.5 Wh kg-1 at a power density of 850 W kg-1, along with an superior cycling performance (108.0% specific capacitance retained after 10000 cycles at 5 A g-1). These impressive results make Co2P HNF a promising candidate for supercapacitor applications.

  16. Preliminary study of Friction disk type turbine for S-CO{sub 2} cycle application (2016 Autumn Meeting of the KNS)

    Energy Technology Data Exchange (ETDEWEB)

    Baik, Seungjoon; Heo, Jin Young; Kwon, Jinsu; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2016-10-15

    Among the next generation reactors, a sodium-cooled fast reactor (SFR) with the supercritical carbon dioxide (S-CO{sub 2}) Brayton cycle has been suggested as the advanced energy solution. The S-CO{sub 2} power conversion system can achieve high efficiency with the SFR core thermal condition (450-550℃) and also can reduce the total cycle footprint due to high density of the working fluid. Moreover, the S-CO{sub 2} power cycle can reduce the accident consequence compared to the steam Rankine cycle due to the mild sodium-CO{sub 2} interaction. The S-CO{sub 2} power cycle has different characteristic compare to the conventional steam Rankine cycle or gas Brayton cycle. For the turbine section, the expansion ratio is much smaller than the other cycles. Thus, different type of turbine should be evaluated for the advanced S-CO{sub 2} technology and the KAIST research team considered a friction disk type turbine (Tesla turbine) concept for the S-CO{sub 2} cycle applications. In this paper, the test result and analysis of a lab-scale Tesla turbine in the KAIST S-CO{sub 2} experimental facility (S-CO{sub 2}PE) are briefly discussed. The KAIST research team investigated a friction disk type turbine, named as Tesla turbine, for the S-CO{sub 2} power cycle applications. The preliminary test of a lab-scale Tesla turbine was conducted with compressed air. The generator, nozzle angle and bearing performances are tested. With the best performing nozzle angle and bearing, the Tesla turbine was tested under various S-CO{sub 2} conditions. As a result, the S-CO{sub 2}PE facility generated electricity (0.5-5W). The isentropic efficiency was relatively low (0.8-1.3%). It seemed that, the authors need further study to understand the main mechanism and maximize the efficiency. After developing the design methodology, the design optimization will be conducted to show the applicability of the friction disk type turbine for the S-CO{sub 2} power cycle.

  17. Hollow Co2P nanoflowers assembled from nanorods for ultralong cycle-life supercapacitors.

    Science.gov (United States)

    Cheng, Ming; Fan, Hongsheng; Xu, Yingying; Wang, Rongming; Zhang, Xixiang

    2017-09-28

    Hollow Co 2 P nanoflowers (Co 2 P HNFs) were successfully prepared via a one-step, template-free method. Microstructure analysis reveals that Co 2 P HNFs are assembled from nanorods and possess abundant mesopores and an amorphous carbon shell. Density functional theory calculations and electrochemical measurements demonstrate the high electrical conductivity of Co 2 P. Benefiting from the unique nanostructures, when employed as an electrode material for supercapacitors, Co 2 P HNFs exhibit a high specific capacitance, an outstanding rate capability, and an ultralong cycling stability. Furthermore, the constructed Co 2 P HNF//AC ASC exhibits a high energy density of 30.5 W h kg -1 at a power density of 850 W kg -1 , along with a superior cycling performance (108.0% specific capacitance retained after 10 000 cycles at 5 A g -1 ). These impressive results make Co 2 P HNFs a promising candidate for supercapacitor applications.

  18. Potential Improvements of Supercritical Recompression CO2 Brayton Cycle Coupled with KALIMER-600 by Modifying Critical Point of CO2

    International Nuclear Information System (INIS)

    Jeong, Woo Seok; Lee, Jeong Ik; Jeong, Yong Hoon; No, Hee Cheon

    2010-01-01

    Most of the existing designs of a Sodium cooled Fast Reactor (SFR) have a Rankine cycle as an electric power generation cycle. This has the risk of a sodium water reaction. To prevent any hazards from a sodium water reaction, an indirect Brayton cycle using Supercritical Carbon dioxide (S-CO 2 ) as the working fluids for a SFR is an alternative approach to improve the current SFR design. The supercritical Brayton cycle is defined as a cycle with operating conditions above the critical point and the main compressor inlet condition located slightly above the critical point of working fluid. This is because the main advantage of the cycle comes from significantly decreased compressor work just above the critical point due to high density near boundary between supercritical state and subcritical state. For this reason, the minimum temperature and pressure of cycle are just above the CO 2 critical point. In other words, the critical point acts as a limitation of the lowest operating condition of the cycle. In general, lowering the minimum temperature of a thermodynamic cycle can increase the efficiency and the minimum temperature can be decreased by shifting the critical point of CO 2 as mixed with other gases. In this paper, potential enhancement of S-CO 2 cycle coupled with KALIMER-600, which has been developed at KAERI, was investigated using a developed cycle code with a gas mixture property program

  19. A Conceptual Study of Using an Isothermal Compressor on a Supercritical CO{sub 2} Brayton Cycle for SMART Application

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Jin Young; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of); Ahn, Yoonhan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    To maximize the benefits of modularization, the supercritical CO{sub 2} (S-CO{sub 2}) power cycle can replace the conventional steam Rankine cycle to increase the cycle efficiency and reduce its system size. Previous works have been conducted to evaluate potential advantages of applying the S-CO{sub 2} cycle to SMRs, specifically to SMART (System-integrated Modular Advanced Reactor) which is an integral SMR developed by KAERI (Korea Atomic Energy Institute). One of the optimized S-CO{sub 2} cycle layouts is the recompressing Brayton cycle. This paper attempts to improve the cycle layout by replacing the conventional compressor with an isothermal compressor, of which its potential in the S-CO{sub 2} power cycle is conceptually being evaluated. The SMR applications, for which SMART reactor has been represented, can take advantage of the currently developing S-CO{sub 2} cycle greatly by the reduction of size. By introducing the isothermal compressor, the cycle layout considered in has been further improved by increasing the cycle net efficiency by around 0.5%.

  20. Thermoeconomic analysis of a novel zero-CO2-emission high-efficiency power cycle using LNG coldness

    International Nuclear Information System (INIS)

    Liu, Meng; Lior, Noam; Zhang, Na; Han, Wei

    2009-01-01

    This paper presents a thermoeconomic analysis aimed at the optimization of a novel zero-CO 2 and other emissions and high-efficiency power and refrigeration cogeneration system, COOLCEP-S (Patent pending), which uses the liquefied natural gas (LNG) coldness during its revaporization. It was predicted that at the turbine inlet temperature (TIT) of 900 C, the energy efficiency of the COOLCEP-S system reaches 59%. The thermoeconomic analysis determines the specific cost, the cost of electricity, the system payback period and the total net revenue. The optimization started by performing a thermodynamic sensitivity analysis, which has shown that for a fixed TIT and pressure ratio, the pinch point temperature difference in the recuperator, (delta)T p1 , and that in the condenser, (delta)T p2 are the most significant unconstrained variables to have a significant effect on the thermal performance of novel cycle. The payback period of this novel cycle (with fixed net power output of 20 MW and plant life of 40 years) was ∝5.9 years at most, and would be reduced to ∝3.1 years at most when there is a market for the refrigeration byproduct. The capital investment cost of the economically optimized plant is estimated to be about 1000 /kWe, and the cost of electricity is estimated to be 0.34-0.37 CNY/kWh (∝0.04 USD/kWh). These values are much lower than those of conventional coal power plants being installed at this time in China, which, in contrast to COOLCEP-S, do produce CO 2 emissions at that. (author)

  1. RANS simulation of a radial compressor for supercritical CO{sub 2} Brayton cycle

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Gu; Cho, Seong Kuk; Lee, Jekyoung; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of); Cha, Jae Eun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Si Woo [Jinsol Turbo, Daejeon (Korea, Republic of)

    2016-10-15

    S-CO{sub 2} cycle has a small footprint due to the compact turbomachine and heat exchanger. It was found that the S-CO{sub 2} compressor consumes small compression work if the operating conditions approach to the critical point (7.38MPa, 31.1℃). Therefore, this reduced compression work contributes to high cycle efficiency. Due to the above mentioned advantages, the S-CO{sub 2} cycle can be applied to various heat sources such as coal power, bottoming cycle of fuel cells, and the next generation nuclear systems. To demonstrate the S-CO{sub 2} cycle performance, an integral test facility is necessary. Therefore, the joint research team of KAERI, KAIST, POSTECH designed a supercritical CO{sub 2} integral experiment loop (SCIEL). The experimental data from this loop are accumulating in various conditions, rotational speed. The design of a S-CO{sub 2} compressor operating near the critical point is one of the major technical challenges in the development of cycle components. A radial compressor geometry designed for supercritical CO{sub 2} loop was utilized for CFD analysis. The preliminary results were compared to the experimental data. In this study, the authors present a CFD approach with accurate CSV type property table. Compared results showed reasonable difference between CFD and experiment except for efficiency curve at 35,000rpm. In future works, the loss models used for the design of S-CO{sub 2} compressor will be validated, and established with CFD results.

  2. Performance Estimation of Supercritical CO2 Cycle for the PG-SFR application with Heat Sink Temperature Variation

    International Nuclear Information System (INIS)

    Ahn, Yoonhan; Cho, Seong Kuk; Lee, Jeong Ik

    2015-01-01

    The heat sink temperature conditions are referred from the annual database of sea water temperature in East sea. When the heat sink temperature increases, the compressor inlet temperature can be influenced and the sudden power decrease can happen due to the large water pumping power. When designing the water pump, the pumping margin should be considered as well. As a part of Prototype Generation IV Sodium-cooled Fast Reactor (PG-SFR) development, the Supercritical CO 2 cycle (S-CO 2 ) is considered as one of the promising candidate that can potentially replace the steam Rankine cycle. S-CO 2 cycle can achieve distinctively high efficiency compared to other Brayton cycles and even competitive performance to the steam Rankine cycle under the mild turbine inlet temperature region. Previous studies explored the optimum size of the S-CO 2 cycle considering component designs including turbomachinery, heat exchangers and pipes. Based on the preliminary design, the thermal efficiency is 31.5% when CO 2 is sufficiently cooled to the design temperature. However, the S-CO 2 compressor performance is highly influenced by the inlet temperature and the compressor inlet temperature can be changed when the heat sink temperature, in this case sea water temperature varies. To estimate the S-CO 2 cycle performance of PG-SFR in the various regions, a Quasi-static system analysis code for S-CO 2 cycle is developed by the KAIST research team. A S-CO 2 cycle for PG-SFR is designed and assessed for off-design performance with the heat sink temperature variation

  3. Developing a zero-CO{sub 2}-emission coal combustion process for power generation; Entwicklung eines CO{sub 2}-emissionsfreien Kohleverbrennungsprozesses zur Stromerzeugung

    Energy Technology Data Exchange (ETDEWEB)

    Kneer, R.; Abel, D.; Niehuis, R.; Meier, H.R.; Modigell, M.; Peters, N. [RWTH Aachen (Germany)

    2005-07-01

    Besides measures for efficiency improvements by means of increased steam parameters, research on oxyfuel cycles in the main strategy for reduction of CO{sub 2}-emissions from fossil coal-fired power plants. The largest publicity founded German oxyfuel project is the so-called OXYCOAL-AC project, where 6 institutes from RWTH Aachen University and 5 industrial partners collaborate in the development of a CO{sub 2}-free coal combustion power plant cycle. This will be achieved by sing pure oxygen and recirculated CO{sub 2} for the combustion process. The oxygen is provided by a high temperature ceramic membrane module, which separates oxygen from an air feed flow. The challenges of this project and the related research topics are presented by discussing the main components of the OXYCOAL-AC cycle. While this description of the cycle is based on a 400 MW reference power plant, its realisation at the existing test facility at RWTH Aachen University will also be explained. Finally, an outlook on future activities is presented. (orig.)

  4. Potential improvements of supercritical recompression CO2 Brayton cycle by mixing other gases for power conversion system of a SFR

    International Nuclear Information System (INIS)

    Jeong, Woo Seok; Lee, Jeong Ik; Jeong, Yong Hoon

    2011-01-01

    Highlights: → S-CO 2 cycle could be enhanced by shifting the critical point of working fluids using gas mixture. → In-house cycle code was developed to analyze supercritical Brayton cycles with gas mixture. → Gas mixture candidates were selected through a screening process: CO 2 mixing with N 2 , O 2 , He, and Ar. → CO 2 -He binary mixture shows the highest cycle efficiency increase. → Lowering the critical temperature and critical pressure of the coolant has a positive effect on the total cycle efficiency. - Abstract: A sodium-cooled fast reactor (SFR) is one of the strongest candidates for the next generation nuclear reactor. However, the conventional design of a SFR concept with an indirect Rankine cycle is subjected to a possible sodium-water reaction. To prevent any hazards from sodium-water reaction, a SFR with the Brayton cycle using Supercritical Carbon dioxide (S-CO 2 ) as the working fluid can be an alternative approach to improve the current SFR design. However, the S-CO 2 Brayton cycle is more sensitive to the critical point of working fluids than other Brayton cycles. This is because compressor work is significantly decreased slightly above the critical point due to high density of CO 2 near the boundary between the supercritical state and the subcritical state. For this reason, the minimum temperature and pressure of cycle are just above the CO 2 critical point. In other words, the critical point acts as a limitation of the lowest operating condition of the cycle. In general, lowering the rejection temperature of a thermodynamic cycle can increase the efficiency. Therefore, changing the critical point of CO 2 can result in an improvement of the total cycle efficiency with the same cycle layout. A small amount of other gases can be added in order to change the critical point of CO 2 . The direction and range of the critical point variation of CO 2 depends on the mixed component and its amount. Several gases that show chemical stability with

  5. Catalysts for long-life closed-cycle CO2 lasers

    Science.gov (United States)

    Schryer, David R.; Sidney, Barry D.; Miller, Irvin M.; Hess, Robert V.; Wood, George M.; Batten, Carmen E.; Burney, Lewis G.; Hoyt, Ronald F.; Paulin, Patricia A.; Brown, Kenneth G.

    1987-01-01

    Long-life, closed-cycle operation of pulsed CO2 lasers requires catalytic CO-O2 recombination both to remove O2, which is formed by discharge-induced CO2 decomposition, and to regenerate CO2. Platinum metal on a tin (IV) oxide substrate (Pt/SnO2) has been found to be an effective catalyst for such recombination in the desired temperature range of 25 to 100 C. This paper presents a description of ongoing research at NASA-LaRC on Pt/SnO2 catalyzed CO-O2 recombination. Included are studies with rare-isotope gases since rare-isotope CO2 is desirable as a laser gas for enhanced atmospheric transmission. Results presented include: (1) achievement of 98% to 100% conversion of a stoichiometric mixture of CO and O2 to CO2 for 318 hours (greater than 1 x 10 to the 6th power seconds), continuous, at a catalyst temperature of 60 C, and (2) development of a technique verified in a 30-hour test, to prevent isotopic scrambling when CO-18 and O-18(2) are reacted in the presence of a common-isotope Pt/Sn O-16(2) catalyst.

  6. Analysis of Combined Cycle Power Plants with Chemical Looping Reforming of Natural Gas and Pre-Combustion CO2 Capture

    Directory of Open Access Journals (Sweden)

    Shareq Mohd Nazir

    2018-01-01

    Full Text Available In this paper, a gas-fired combined cycle power plant subjected to a pre-combustion CO2 capture method has been analysed under different design conditions and different heat integration options. The power plant configuration includes the chemical looping reforming (CLR of natural gas (NG, water gas shift (WGS process, CO2 capture and compression, and a hydrogen fuelled combined cycle to produce power. The process is denoted as a CLR-CC process. One of the main parameters that affects the performance of the process is the pressure for the CLR. The process is analysed at different design pressures for the CLR, i.e., 5, 10, 15, 18, 25 and 30 bar. It is observed that the net electrical efficiency increases with an increase in the design pressure in the CLR. Secondly, the type of steam generated from the cooling of process streams also effects the net electrical efficiency of the process. Out of the five different cases including the base case presented in this study, it is observed that the net electrical efficiency of CLR-CCs can be improved to 46.5% (lower heating value of NG basis by producing high-pressure steam through heat recovery from the pre-combustion process streams and sending it to the Heat Recovery Steam Generator in the power plant.

  7. Integration of the steam cycle and CO2 capture process in a decarbonization power plant

    International Nuclear Information System (INIS)

    Xu, Gang; Hu, Yue; Tang, Baoqiang; Yang, Yongping; Zhang, Kai; Liu, Wenyi

    2014-01-01

    A new integrated system with power generation and CO 2 capture to achieve higher techno-economic performance is proposed in this study. In the new system, three measures are adopted to recover the surplus energy from the CO 2 capture process. The three measures are as follows: (1) using a portion of low-pressure steam instead of high-pressure extracted steam by installing the steam ejector, (2) mixing a portion of flash-off water with the extracted steam to utilize the superheat degree of the extracted steam, and (3) recycling the low-temperature waste heat from the CO 2 capture process to heat the condensed water. As a result, the power output of the new integrated system is 107.61 MW higher than that of a decarbonization power plant without integration. The efficiency penalty of CO 2 capture is expected to decrease by 4.91%-points. The increase in investment produced by the new system is 3.25 M$, which is only 0.88% more than the total investment of a decarbonization power plant without integration. Lastly, the cost of electricity and CO 2 avoided is 15.14% and 33.1% lower than that of a decarbonization power generation without integration, respectively. The promising results obtained in this study provide a new approach for large-scale CO 2 removal with low energy penalty and economic cost. - Highlights: • Energy equilibrium in CO 2 capture process is deeply analyzed in this paper. • System integration is conducted in a coal-fired power plant with CO 2 capture. • The steam ejector is introduced to utilize the waste energy from CO 2 capture process. • Thermodynamic, exergy and techno-economic analyses are quantitatively conducted. • Energy-saving effects are found in the new system with minimal investment

  8. Thermoeconomic analysis of a novel zero-CO{sub 2}-emission high-efficiency power cycle using LNG coldness

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Meng [China National Institute of Standardization, Beijing 100088 (China); Lior, Noam [Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104-6315 (United States); Zhang, Na; Han, Wei [Institute of Engineering Thermophysics, Chinese Academy of Sciences, P.O. Box 2706, Beijing 100190 (China)

    2009-11-15

    This paper presents a thermoeconomic analysis aimed at the optimization of a novel zero-CO{sub 2} and other emissions and high-efficiency power and refrigeration cogeneration system, COOLCEP-S (Patent pending), which uses the liquefied natural gas (LNG) coldness during its revaporization. It was predicted that at the turbine inlet temperature (TIT) of 900 C, the energy efficiency of the COOLCEP-S system reaches 59%. The thermoeconomic analysis determines the specific cost, the cost of electricity, the system payback period and the total net revenue. The optimization started by performing a thermodynamic sensitivity analysis, which has shown that for a fixed TIT and pressure ratio, the pinch point temperature difference in the recuperator, {delta}T{sub p1}, and that in the condenser, {delta}T{sub p2} are the most significant unconstrained variables to have a significant effect on the thermal performance of novel cycle. The payback period of this novel cycle (with fixed net power output of 20 MW and plant life of 40 years) was {proportional_to}5.9 years at most, and would be reduced to {proportional_to}3.1 years at most when there is a market for the refrigeration byproduct. The capital investment cost of the economically optimized plant is estimated to be about 1000 /kWe, and the cost of electricity is estimated to be 0.34-0.37 CNY/kWh ({proportional_to}0.04 USD/kWh). These values are much lower than those of conventional coal power plants being installed at this time in China, which, in contrast to COOLCEP-S, do produce CO{sub 2} emissions at that. (author)

  9. Thermoeconomic analysis of a novel zero-CO{sub 2}-emission high-efficiency power cycle using LNG coldness

    Energy Technology Data Exchange (ETDEWEB)

    Liu Meng [China National Institute of Standardization, Beijing 100088 (China)], E-mail: liumeng@cnis.gov.cn; Lior, Noam [Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104-6315 (United States)], E-mail: lior@seas.upenn.edu; Zhang Na; Han Wei [Institute of Engineering Thermophysics, Chinese Academy of Sciences, P.O. Box 2706, Beijing 100190 (China)

    2009-11-15

    This paper presents a thermoeconomic analysis aimed at the optimization of a novel zero-CO{sub 2} and other emissions and high-efficiency power and refrigeration cogeneration system, COOLCEP-S (Patent pending), which uses the liquefied natural gas (LNG) coldness during its revaporization. It was predicted that at the turbine inlet temperature (TIT) of 900 deg. C, the energy efficiency of the COOLCEP-S system reaches 59%. The thermoeconomic analysis determines the specific cost, the cost of electricity, the system payback period and the total net revenue. The optimization started by performing a thermodynamic sensitivity analysis, which has shown that for a fixed TIT and pressure ratio, the pinch point temperature difference in the recuperator, {delta}T{sub p1}, and that in the condenser, {delta}T{sub p2} are the most significant unconstrained variables to have a significant effect on the thermal performance of novel cycle. The payback period of this novel cycle (with fixed net power output of 20 MW and plant life of 40 years) was {approx}5.9 years at most, and would be reduced to {approx}3.1 years at most when there is a market for the refrigeration byproduct. The capital investment cost of the economically optimized plant is estimated to be about 1000 $/kWe, and the cost of electricity is estimated to be 0.34-0.37 CNY/kWh ({approx}0.04 $/kWh). These values are much lower than those of conventional coal power plants being installed at this time in China, which, in contrast to COOLCEP-S, do produce CO{sub 2} emissions at that.

  10. Assessment of gas cooled fast reactor with indirect supercritical CO2 cycle

    International Nuclear Information System (INIS)

    Hejzlar, P.; Driscoll, M. J.; Dostal, V.; Dumaz, P.; Poullennec, G.; Alpy, N.

    2006-01-01

    Various indirect power cycle options for a helium cooled Gas cooled Fast Reactor (GFR) with particular focus on a supercritical CO 2 (SCO 2 ) indirect cycle are investigated as an alternative to a helium cooled direct cycle GFR. The Balance Of Plant (BOP) options include helium-nitrogen Brayton cycle, supercritical water Rankine cycle, and SCO 2 recompression Brayton power cycle in three versions: (1) basic design with turbine inlet temperature of 550 .deg. C, (2) advanced design with turbine inlet temperature of 650 .deg. C and (3) advanced design with the same turbine inlet temperature and reduced compressor inlet temperature. The indirect SCO 2 recompression cycle is found attractive since in addition to easier BOP maintenance it allows significant reduction of core outlet temperature, making design of the primary system easier while achieving very attractive efficiencies comparable to or slightly lower than, the efficiency of the reference GFR direct cycle design. In addition, the indirect cycle arrangement allows significant reduction of the GFR 'proximate-containment' and the BOP for the SCO 2 cycle is very compact. Both these factors will lead to reduced capital cost

  11. Efficient electrochemical CO2 conversion powered by renewable energy.

    Science.gov (United States)

    Kauffman, Douglas R; Thakkar, Jay; Siva, Rajan; Matranga, Christopher; Ohodnicki, Paul R; Zeng, Chenjie; Jin, Rongchao

    2015-07-22

    The catalytic conversion of CO2 into industrially relevant chemicals is one strategy for mitigating greenhouse gas emissions. Along these lines, electrochemical CO2 conversion technologies are attractive because they can operate with high reaction rates at ambient conditions. However, electrochemical systems require electricity, and CO2 conversion processes must integrate with carbon-free, renewable-energy sources to be viable on larger scales. We utilize Au25 nanoclusters as renewably powered CO2 conversion electrocatalysts with CO2CO reaction rates between 400 and 800 L of CO2 per gram of catalytic metal per hour and product selectivities between 80 and 95%. These performance metrics correspond to conversion rates approaching 0.8-1.6 kg of CO2 per gram of catalytic metal per hour. We also present data showing CO2 conversion rates and product selectivity strongly depend on catalyst loading. Optimized systems demonstrate stable operation and reaction turnover numbers (TONs) approaching 6 × 10(6) molCO2 molcatalyst(-1) during a multiday (36 h total hours) CO2 electrolysis experiment containing multiple start/stop cycles. TONs between 1 × 10(6) and 4 × 10(6) molCO2 molcatalyst(-1) were obtained when our system was powered by consumer-grade renewable-energy sources. Daytime photovoltaic-powered CO2 conversion was demonstrated for 12 h and we mimicked low-light or nighttime operation for 24 h with a solar-rechargeable battery. This proof-of-principle study provides some of the initial performance data necessary for assessing the scalability and technical viability of electrochemical CO2 conversion technologies. Specifically, we show the following: (1) all electrochemical CO2 conversion systems will produce a net increase in CO2 emissions if they do not integrate with renewable-energy sources, (2) catalyst loading vs activity trends can be used to tune process rates and product distributions, and (3) state-of-the-art renewable-energy technologies are sufficient

  12. Thermal analysis of supercritical CO2 power cycles: Assessment of their suitability to the forthcoming sodium fast reactors

    International Nuclear Information System (INIS)

    Pérez-Pichel, G.D.; Linares, J.I.; Herranz, L.E.; Moratilla, B.Y.

    2012-01-01

    Highlights: ► This paper investigates the potential use of S-CO 2 cycles in SFRs. ► A wide range of configurations have been explored. ► It is feasible to reach a thermal efficiency as high as 43.5%. ► A sensitivity analysis together with an exergy study have been done. ► Potential use in SFRs of recompression S-CO 2 cycles for their balance of plant. - Abstract: Sodium fast reactors (SFRs) potential to meet Gen. IV requirements is broadly acknowledged worldwide. The scientific and technological experience accumulated by operating test reactors and, even, by running commercial reactors, makes them be considered as the closest Gen. IV option in the near future. In the past their balance of plant has been always based on Rankine cycles. This paper investigates the potential use of supercritical recompression CO 2 cycles (S-CO 2 ) in SFRs on the basis of the working parameters foreseen within the European Sodium Fast Reactor (ESFR) project. A wide range of configurations have been explored, from the simplest one to combined cycles (with organic Rankine cycles, ORC), and a comparison has been set in terms of thermal efficiency. As a result, it has been found out that the most basic configuration could reach a thermal efficiency as high as 43.31%, which is comparable to that obtained through super-critical Rankine cycles proposed elsewhere. A sensitivity analysis together with an exergy study of this configuration, pointed the pre-cooler and IHX Na–CO 2 as key components in the cycle performance. These results highlight a main conclusion: the potential use in SFRs of recompression S-CO 2 cycles for their balance of plant, whenever a sound and extensive database is built-up on S-CO 2 turbo-machinery and IHX performance.

  13. CO2 reduction potential of future coal gasification based power generation technologies

    International Nuclear Information System (INIS)

    Jansen, D.; Oudhuis, A.B.J.; Van Veen, H.M.

    1992-03-01

    Assessment studies are carried out on coal gasification power plants integrated with gas turbines (IGCC) or molten carbonate fuel cells (MCFC) without and with CO 2 -removal. System elements include coal gasification, high-temperature gas-cleaning, molten carbonate fuel cells or gas turbines, CO shift, membrane separation, CO 2 recovery and a bottoming cycle. Various system configurations are evaluated on the basis of thermodynamic computations. The energy balances of the various system configurations clearly indicate that integrated coal gasification MCFC power plants (IGMCFC) with CO 2 removal have high efficiencies (42-47% LHV) compared to IGCC power plants with CO 2 -removal (33-38% LHV) and that the CO 2 -removal is simplified due to the specific properties of the molten carbonate fuel cells. IGMCFC is therefore an option with future prospective in the light of clean coal technologies for power generation with high energy efficiencies and low emissions. 2 figs., 3 tabs., 10 refs

  14. Energy analysis and design of mixed CO{sub 2}/steam gas turbine cycles

    Energy Technology Data Exchange (ETDEWEB)

    Bram, S; De Ruyck, J [Vrije Universiteit Brussel, Brussels (Belgium). Dept. of Mechanics

    1995-06-01

    The capturing and disposal of CO{sub 2} from power plant exhaust gases is a possible route for reducing CO{sub 2} emissions. The present paper investigates the full recirculation of exhaust gases in a gas turbine cycle, combined with the injection of steam or water. Such recirculation leads to an exhaust gas with very high CO{sub 2} concentration (95% or more). Different regenerative cycle layouts are proposed and analyzed for efficiency, exergy destruction and technical feasibility. Pinch Technology methods are next applied to find the best configuration for heat regeneration and injection of water. From this analysis, dual pressure evaporation with water injection in the intercooler emerges as an interesting option. 3 refs., 2 figs., 1 tab.

  15. CO/sub 2/ carbon cycle and climate interactions

    Energy Technology Data Exchange (ETDEWEB)

    Grassl, H; Maier-Reimer, E; Degens, E T; Kempe, S; Spitzy, A

    1984-03-01

    Past and expected emissions of anthropogenic CO/sub 2/ stimulate carbon cycle and climate research. Prognoses of future CO/sub 2/ levels depend on energy scenarios and on the reaction of the biosphere and hydrosphere to elevated atmospheric CO/sub 2/ concentrations. The reaction of the reservoirs vegetation, freshwater and oceans to disturbances of the carbon cycle is reviewed. For the oceans first results of a simple carbon cycle model implanted in a three-dimensional general circulation model are presented. This model allows experiments not possible with previous box models.

  16. Improvement of supercritical CO2 Brayton cycle using binary gas mixture

    International Nuclear Information System (INIS)

    Jeong, Woo Seok

    2011-02-01

    A Sodium-cooled Fast Reactor (SFR) is one of the strongest candidates for the next generation nuclear reactor. However, the conventional design of a SFR concept with an indirect Rankine cycle is inevitably subjected to a sodium-water reaction. To prevent hazardous situation caused by sodium-water reaction, the SFR with Brayton cycle using Supercritical Carbon dioxide (S-CO 2 cycle) as a working fluid can be an alternative approach. The S-CO 2 Brayton cycle is more sensitive to the critical point of working fluids than other Brayton cycles. This is because compressor work significantly decreases at slightly above the critical point due to high density near the boundary between the supercritical state and the subcritical state. For this reason, the minimum temperature and pressure of cycle are just above the CO 2 critical point. The critical point acts as a limitation of the lowest operating condition of the cycle. In general, lowering the rejection temperature of a thermodynamic cycle increases the efficiency and thus, changing the critical point of CO 2 can result in an improvement of the total cycle efficiency with the same cycle layout. Modifying the critical point of the working fluid can be done by adding other gases to CO 2 . The direction and range of the CO 2 critical point variation depends on the mixed component and its amount. In particular, chemical reactivity of the gas mixture itself and the gas mixture with sodium at high temperatures are of interest. To modify the critical point of the working fluid, several gases were chosen as candidates by which chemical stability with sodium within the interested range of cycle operating condition was assured: CO 2 was mixed with N 2 , O 2 , He, Ar and Xe. To evaluate the effect of shifting the critical point and changes in the properties of the S-CO 2 Brayton cycle, a supercritical Brayton cycle analysis code connected with the REFPROP program from the NIST was developed. The developed code is for evaluating

  17. Advanced modeling and simulation of integrated gasification combined cycle power plants with CO2-capture

    International Nuclear Information System (INIS)

    Rieger, Mathias

    2014-01-01

    The objective of this thesis is to provide an extensive description of the correlations in some of the most crucial sub-processes for hard coal fired IGCC with carbon capture (CC-IGCC). For this purpose, process simulation models are developed for four industrial gasification processes, the CO-shift cycle, the acid gas removal unit, the sulfur recovery process, the gas turbine, the water-/steam cycle and the air separation unit (ASU). Process simulations clarify the influence of certain boundary conditions on plant operation, performance and economics. Based on that, a comparative benchmark of CC-IGCC concepts is conducted. Furthermore, the influence of integration between the gas turbine and the ASU is analyzed in detail. The generated findings are used to develop an advanced plant configuration with improved economics. Nevertheless, IGCC power plants with carbon capture are not found to be an economically efficient power generation technology at present day boundary conditions.

  18. The potential of renewables versus natural gas with CO2 capture and storage for power generation under CO2 constraints

    NARCIS (Netherlands)

    Van Den Broek, Machteld; Berghout, Niels; Rubin, Edward S.

    2015-01-01

    The costs of intermittent renewable energy systems (IRES) and power storage technologies are compared on a level playing field to those of natural gas combined cycle power plants with CO2 capture and storage (NGCC-CCS). To account for technological progress over time, an "experience

  19. COOLCEP (cool clean efficient power): A novel CO2-capturing oxy-fuel power system with LNG (liquefied natural gas) coldness energy utilization

    International Nuclear Information System (INIS)

    Zhang, Na; Lior, Noam; Liu, Meng; Han, Wei

    2010-01-01

    A novel liquefied natural gas (LNG) fueled power plant is proposed, which has virtually zero CO 2 and other emissions and a high efficiency. The plant operates as a subcritical CO 2 Rankine-like cycle. Beside the power generation, the system provides refrigeration in the CO 2 subcritical evaporation process, thus it is a cogeneration system with two valued products. By coupling with the LNG evaporation system as the cycle cold sink, the cycle condensation process can be achieved at a temperature much lower than ambient, and high-pressure liquid CO 2 can be withdrawn from the cycle without consuming additional power. Two system variants are analyzed and compared, COOLCEP-S and COOLCEP-C. In the COOLCEP-S cycle configuration, the working fluid in the main turbine expands only to the CO 2 condensation pressure; in the COOLCEP-C cycle configuration, the turbine working fluid expands to a much lower pressure (near-ambient) to produce more power. The effects of some key parameters, the turbine inlet temperature and the backpressure, on the systems' performance are investigated. It was found that at the turbine inlet temperature of 900 o C, the energy efficiency of the COOLCEP-S system reaches 59%, which is higher than the 52% of the COOLCEP-C one. The capital investment cost of the economically optimized plant is estimated to be about 750 EUR/kWe and the payback period is about 8-9 years including the construction period, and the cost of electricity is estimated to be 0.031-0.034 EUR/kWh.

  20. Volcanic CO2 Emissions and Glacial Cycles: Coupled Oscillations

    Science.gov (United States)

    Burley, J. M.; Huybers, P. J.; Katz, R. F.

    2016-12-01

    Following the mid-Pleistocene transition, the dominant period of glacial cycles changed from 40 ka to 100 ka. It is broadly accepted that the 40 ka glacial cycles were driven by cyclical changes in obliquity. However, this forcing does not explain the 100 ka glacial cycles. Mechanisms proposed for 100 ka cycles include isostatic bed depression and proglacial lakes destabilising the Laurentide ice sheet, non-linear responses to orbital eccentricity, and Antarctic ice sheets influencing deep-ocean stratification. None of these are universally accepted. Here we investigate the hypothesis that variations in volcanic CO2 emissions can cause 100 ka glacial cycles. Any proposed mechanism for 100 ka glacial cycles must give the Earth's climate system a memory of 10^4 - 10^5years. This timescale is difficult to achieve for surface processes, however it is possible for the solid Earth. Recent work suggests volcanic CO2 emissions change in response to glacial cycles [1] and that there could be a 50 ka delay in that response [2]. Such a lagged response could drive glacial cycles from 40 ka cycles to an integer multiple of the forcing period. Under what conditions could the climate system admit such a response? To address this, we use a simplified climate model modified from Huybers and Tziperman [3]. Our version comprises three component models for energy balance, ice sheet growth and atmospheric CO2 concentration. The model is driven by insolation alone with other components varying according to a system of coupled, differential equations. The model is run for 500 ka to produce several glacial cycles and the resulting changes in global ice volume and atmospheric CO2 concentration.We obtain a switch from 40 ka to 100 ka cycles as the volcanic CO2 response to glacial cycles is increased. These 100 ka cycles are phase-locked to obliquity, lasting 80 or 120 ka. Whilst the MOR response required (in this model) is larger than plausible estimates based on [2], it illustrates the

  1. Evaluating the climate benefits of CO2-enhanced oil recovery using life cycle analysis.

    Science.gov (United States)

    Cooney, Gregory; Littlefield, James; Marriott, Joe; Skone, Timothy J

    2015-06-16

    This study uses life cycle analysis (LCA) to evaluate the greenhouse gas (GHG) performance of carbon dioxide (CO2) enhanced oil recovery (EOR) systems. A detailed gate-to-gate LCA model of EOR was developed and incorporated into a cradle-to-grave boundary with a functional unit of 1 MJ of combusted gasoline. The cradle-to-grave model includes two sources of CO2: natural domes and anthropogenic (fossil power equipped with carbon capture). A critical parameter is the crude recovery ratio, which describes how much crude is recovered for a fixed amount of purchased CO2. When CO2 is sourced from a natural dome, increasing the crude recovery ratio decreases emissions, the opposite is true for anthropogenic CO2. When the CO2 is sourced from a power plant, the electricity coproduct is assumed to displace existing power. With anthropogenic CO2, increasing the crude recovery ratio reduces the amount of CO2 required, thereby reducing the amount of power displaced and the corresponding credit. Only the anthropogenic EOR cases result in emissions lower than conventionally produced crude. This is not specific to EOR, rather the fact that carbon-intensive electricity is being displaced with captured electricity, and the fuel produced from that system receives a credit for this displacement.

  2. Thermodynamic analyses and optimization of a recompression N2O Brayton power cycle

    International Nuclear Information System (INIS)

    Sarkar, Jahar

    2010-01-01

    Thermodynamic analyses and simultaneous optimizations of cycle pressure ratio and flow split fraction to get maximum efficiency of N 2 O recompression Brayton cycle have been performed to study the effects of various operating conditions and component performances. The energetic as well as exergetic performance comparison with its counterpart recompression CO 2 cycle is presented as well. Optimization shows that the optimum minimum cycle pressure is close to pseudo-critical pressure for supercritical cycle, whereas saturation pressure corresponding to minimum cycle temperature for condensation cycle. Results show that the maximum thermal efficiency increases with decrease in minimum cycle temperature and increase in both maximum cycle pressure and temperature. Influence of turbine performance on cycle efficiency is more compared to that of compressors, HTR (high temperature recuperator) and LTR (low temperature recuperator). Comparison shows that N 2 O gives better thermal efficiency (maximum deviation of 1.2%) as well as second law efficiency compared to CO 2 for studied operating conditions. Component wise irreversibility distribution shows the similar trends for both working fluids. Present study reveals that N 2 O is a potential option for the recompression power cycle.

  3. Design-theoretical study of cascade CO2 sub-critical mechanical compression/butane ejector cooling cycle

    KAUST Repository

    Petrenko, V.O.

    2011-11-01

    In this paper an innovative micro-trigeneration system composed of a cogeneration system and a cascade refrigeration cycle is proposed. The cogeneration system is a combined heat and power system for electricity generation and heat production. The cascade refrigeration cycle is the combination of a CO2 mechanical compression refrigerating machine (MCRM), powered by generated electricity, and an ejector cooling machine (ECM), driven by waste heat and using refrigerant R600. Effect of the cycle operating conditions on ejector and ejector cycle performances is studied. Optimal geometry of the ejector and performance characteristics of ECM are determined at wide range of the operating conditions. The paper also describes a theoretical analysis of the CO2 sub-critical cycle and shows the effect of the MCRM evaporating temperature on the cascade system performance. The obtained data provide necessary information to design a small-scale cascade system with cooling capacity of 10 kW for application in micro-trigeneration systems. © 2010 Elsevier Ltd and IIR. All rights reserved.

  4. Techno-economic process design of a commercial-scale amine-based CO_2 capture system for natural gas combined cycle power plant with exhaust gas recirculation

    International Nuclear Information System (INIS)

    Ali, Usman; Agbonghae, Elvis O.; Hughes, Kevin J.; Ingham, Derek B.; Ma, Lin; Pourkashanian, Mohamed

    2016-01-01

    Highlights: • EGR is a way to enhance the CO_2 content with reduction in design variables and cost. • Both process and economic analyses are essential to reach the optimum design variables. • Commercial-scale NGCC with and without EGR is presented. • Process design of the amine-based CO_2 capture plant is evaluated for with and without EGR. - Abstract: Post-combustion CO_2 capture systems are gaining more importance as a means of reducing escalating greenhouse gas emissions. Moreover, for natural gas-fired power generation systems, exhaust gas recirculation is a method of enhancing the CO_2 concentration in the lean flue gas. The present study reports the design and scale-up of four different cases of an amine-based CO_2 capture system at 90% capture rate with 30 wt.% aqueous solution of MEA. The design results are reported for a natural gas-fired combined cycle system with a gross power output of 650 MW_e without EGR and with EGR at 20%, 35% and 50% EGR percentage. A combined process and economic analysis is implemented to identify the optimum designs for the different amine-based CO_2 capture plants. For an amine-based CO_2 capture plant with a natural gas-fired combined cycle without EGR, an optimum liquid to gas ratio of 0.96 is estimated. Incorporating EGR at 20%, 35% and 50%, results in optimum liquid to gas ratios of 1.22, 1.46 and 1.90, respectively. These results suggest that a natural gas-fired power plant with exhaust gas recirculation will result in lower penalties in terms of the energy consumption and costs incurred on the amine-based CO_2 capture plant.

  5. Studies of S-CO{sub 2} Power Plant Pipe Design for Small Modular Sodium-cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Seok; Ahn, Yoon Han; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-10-15

    If SFR can be developed into the economical small modular reactor (SMR) for an export from Korea, the expected value can be greater. However, current SFR design may face difficulty in public acceptance due to the potential hazard from sodium-water reaction (SWR) when the current conventional steam Rankine cycle is utilized as a power conversion system for a SFR. In order to eliminate SWR, the Supercritical CO{sub 2} (S-CO{sub 2}) cycle has been proposed. Although there are many researches on S-CO{sub 2} cycle concept and turbomachinery, very few research works considered pipe selection criteria for the S-CO{sub 2} cycle. As one of the most important parts of the plant, this paper will discuss how to select a suitable pipe considering thermal expansion for the S-CO{sub 2} power plant and perform a conceptual design of SFR type SMR. The S-CO{sub 2} cycle can improve the safety of SFR as preventing the SWR by changing the working fluid. Additionally, not only the relatively high efficiency with 450-750 .deg. C turbine inlet temperature, but also the physically compact footprint are advantages of the S-CO{sub 2} cycle. However the pipe design is more complicated than existing power plant because it has high pressure and temperature conditions and needs high mass flow rate. By designing the piping system for a small modular -SFR, the compactness and simplicity of the S-CO{sub 2} cycle are re-confirmed. Moreover, in this paper, realistic and safe pipe design was conducted by considering thermal expansion in the high pressure and temperature conditions. Although total pipe pressure drop is somewhat high, the cycle thermal efficiency is still higher than the existing steam Rankine cycle. Additional study for a larger system such as 300MW class system in MIT report will be conducted in the future study. From the preliminary estimation when the S-CO{sub 2} system becomes large, the pipe diameter may exceed the current ASME standard. This means that more innovative approach

  6. Thermal analysis of supercritical CO{sub 2} power cycles: Assessment of their suitability to the forthcoming sodium fast reactors

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Pichel, G.D., E-mail: gdp@icai.es [Rafael Marino Chair on New Energy Technologies, Comillas Pontifical University, Madrid (Spain); Linares, J.I. [Rafael Marino Chair on New Energy Technologies, Comillas Pontifical University, Madrid (Spain); Herranz, L.E.; Moratilla, B.Y. [Unit of Nuclear Safety Research, CIEMAT, Madrid (Spain)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer This paper investigates the potential use of S-CO{sub 2} cycles in SFRs. Black-Right-Pointing-Pointer A wide range of configurations have been explored. Black-Right-Pointing-Pointer It is feasible to reach a thermal efficiency as high as 43.5%. Black-Right-Pointing-Pointer A sensitivity analysis together with an exergy study have been done. Black-Right-Pointing-Pointer Potential use in SFRs of recompression S-CO{sub 2} cycles for their balance of plant. - Abstract: Sodium fast reactors (SFRs) potential to meet Gen. IV requirements is broadly acknowledged worldwide. The scientific and technological experience accumulated by operating test reactors and, even, by running commercial reactors, makes them be considered as the closest Gen. IV option in the near future. In the past their balance of plant has been always based on Rankine cycles. This paper investigates the potential use of supercritical recompression CO{sub 2} cycles (S-CO{sub 2}) in SFRs on the basis of the working parameters foreseen within the European Sodium Fast Reactor (ESFR) project. A wide range of configurations have been explored, from the simplest one to combined cycles (with organic Rankine cycles, ORC), and a comparison has been set in terms of thermal efficiency. As a result, it has been found out that the most basic configuration could reach a thermal efficiency as high as 43.31%, which is comparable to that obtained through super-critical Rankine cycles proposed elsewhere. A sensitivity analysis together with an exergy study of this configuration, pointed the pre-cooler and IHX{sub Na-CO{sub 2}} as key components in the cycle performance. These results highlight a main conclusion: the potential use in SFRs of recompression S-CO{sub 2} cycles for their balance of plant, whenever a sound and extensive database is built-up on S-CO{sub 2} turbo-machinery and IHX performance.

  7. COOLCEP (cool clean efficient power): A novel CO{sub 2}-capturing oxy-fuel power system with LNG (liquefied natural gas) coldness energy utilization

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Na; Han, Wei [Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190 (China); Lior, Noam [Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104-6315 (United States); Liu, Meng [Division of Research and Environment Standardization, China National Institute of Standardization, Beijing 100080 (China)

    2010-02-15

    A novel liquefied natural gas (LNG) fueled power plant is proposed, which has virtually zero CO{sub 2} and other emissions and a high efficiency. The plant operates as a subcritical CO{sub 2} Rankine-like cycle. Beside the power generation, the system provides refrigeration in the CO{sub 2} subcritical evaporation process, thus it is a cogeneration system with two valued products. By coupling with the LNG evaporation system as the cycle cold sink, the cycle condensation process can be achieved at a temperature much lower than ambient, and high-pressure liquid CO{sub 2} can be withdrawn from the cycle without consuming additional power. Two system variants are analyzed and compared, COOLCEP-S and COOLCEP-C. In the COOLCEP-S cycle configuration, the working fluid in the main turbine expands only to the CO{sub 2} condensation pressure; in the COOLCEP-C cycle configuration, the turbine working fluid expands to a much lower pressure (near-ambient) to produce more power. The effects of some key parameters, the turbine inlet temperature and the backpressure, on the systems' performance are investigated. It was found that at the turbine inlet temperature of 900 C, the energy efficiency of the COOLCEP-S system reaches 59%, which is higher than the 52% of the COOLCEP-C one. The capital investment cost of the economically optimized plant is estimated to be about 750 EUR/kWe and the payback period is about 8-9 years including the construction period, and the cost of electricity is estimated to be 0.031-0.034 EUR/kWh. (author)

  8. Flexible rechargeable Ni//Zn battery based on self-supported NiCo2O4 nanosheets with high power density and good cycling stability

    Directory of Open Access Journals (Sweden)

    Haozhe Zhang

    2018-01-01

    Full Text Available The overall electrochemical performances of Ni–Zn batteries are still far from satisfactory, specifically for rate performance and cycling stability Herein, we demonstrated a high-performance flexible Ni//Zn battery with outstanding durability and high power density based on self-supported NiCo2O4 nanosheets as cathode and Zn nanosheets as anode. This Ni//Zn battery is able to deliver a remarkable capacity of 183.1 mAh g−1 and a good cycling performance (82.7% capacity retention after 3500 cycles. More importantly, this battery achieves an admirable power density of 49.0 kW kg−1 and energy density of 303.8 Wh kg−1, substantially higher than most recently reported batteries. With such excellent electrochemical performance, this battery will have great potential as an ultrafast power source in practical application.

  9. Advanced modeling and simulation of integrated gasification combined cycle power plants with CO{sub 2}-capture

    Energy Technology Data Exchange (ETDEWEB)

    Rieger, Mathias

    2014-04-17

    The objective of this thesis is to provide an extensive description of the correlations in some of the most crucial sub-processes for hard coal fired IGCC with carbon capture (CC-IGCC). For this purpose, process simulation models are developed for four industrial gasification processes, the CO-shift cycle, the acid gas removal unit, the sulfur recovery process, the gas turbine, the water-/steam cycle and the air separation unit (ASU). Process simulations clarify the influence of certain boundary conditions on plant operation, performance and economics. Based on that, a comparative benchmark of CC-IGCC concepts is conducted. Furthermore, the influence of integration between the gas turbine and the ASU is analyzed in detail. The generated findings are used to develop an advanced plant configuration with improved economics. Nevertheless, IGCC power plants with carbon capture are not found to be an economically efficient power generation technology at present day boundary conditions.

  10. Evaluation and Optimization of a Supercritical Carbon Dioxide Power Conversion Cycle for Nuclear Applications

    International Nuclear Information System (INIS)

    Harvego, Edwin A.; McKellar, Michael G.

    2011-01-01

    There have been a number of studies involving the use of gases operating in the supercritical mode for power production and process heat applications. Supercritical carbon dioxide (CO2) is particularly attractive because it is capable of achieving relatively high power conversion cycle efficiencies in the temperature range between 550 C and 750 C. Therefore, it has the potential for use with any type of high-temperature nuclear reactor concept, assuming reactor core outlet temperatures of at least 550 C. The particular power cycle investigated in this paper is a supercritical CO2 Recompression Brayton Cycle. The CO2 Recompression Brayton Cycle can be used as either a direct or indirect power conversion cycle, depending on the reactor type and reactor outlet temperature. The advantage of this cycle when compared to the helium Brayton Cycle is the lower required operating temperature; 550 C versus 850 C. However, the supercritical CO2 Recompression Brayton Cycle requires an operating pressure in the range of 20 MPa, which is considerably higher than the required helium Brayton cycle operating pressure of 8 MPa. This paper presents results of analyses performed using the UniSim process analyses software to evaluate the performance of the supercritical CO2 Brayton Recompression Cycle for different reactor outlet temperatures. The UniSim model assumed a 600 MWt reactor power source, which provides heat to the power cycle at a maximum temperature of between 550 C and 750 C. The UniSim model used realistic component parameters and operating conditions to model the complete power conversion system. CO2 properties were evaluated, and the operating range for the cycle was adjusted to take advantage of the rapidly changing conditions near the critical point. The UniSim model was then optimized to maximize the power cycle thermal efficiency at the different maximum power cycle operating temperatures. The results of the analyses showed that power cycle thermal efficiencies in

  11. Thermodynamic analysis of a novel power plant with LNG (liquefied natural gas) cold exergy exploitation and CO_2 capture

    International Nuclear Information System (INIS)

    Romero Gómez, Manuel; Romero Gómez, Javier; López-González, Luis M.; López-Ochoa, Luis M.

    2016-01-01

    The LNG (liquefied natural gas) regasification process is a source of cold exergy that is suitable to be recovered to improve the efficiency of thermal power plants. In this paper, an innovative power plant with LNG (liquefied natural gas) exergy utilisation and the capture of CO_2 proceeding from the flue gases is presented. It is characterised by the recovery of LNG cold exergy in a closed Brayton cycle and through direct expansion in an expander coupled to an electrical generator. Moreover, this novel power plant configuration allows CO_2 capture, through an oxy-fuel combustion system and a Rankine cycle that operates with the flue gases themselves and in quasi-critical conditions. The greatest advantage of this plant is that all the recoverable LNG exergy is used to increase the efficiency of the CBC (closed Brayton cycle) and in direct expansion whereas, in other power cycles found in literature that associate LNG regasification and CO_2 capture, part of the LNG exergy is used for condensing flue gas CO_2 for its subsequent capture. As a result, a high efficiency power plant is achieved, exceeding 65%, with almost zero greenhouse gas emissions. - Highlights: • LNG cold exergy can be recovered to improve the efficiency of power plants. • High efficiency power plant with almost zero greenhouse gas emissions. • CO_2 capture through an oxy-fuel combustion system and a Rankine cycle. • Sensitivity analysis of key parameters to evaluate the effect on the efficiency. • The exergy available in the LNG represents 34.79% of the fuel exergy.

  12. Conceptual Design of S-CO{sub 2} Brayton Cycle Radial Turbomachinery for KAIST Micro Modular Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seongkuk; Kim, Seong Gu; Lee, Jekyoung; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    KAIST proposed a new SMR design, which utilizes S-CO{sub 2} as the working fluid. It was named as KAIST MMR. Compared with existing SMR concepts, KAIST MMR has advantages of achieving smaller volume of power conversion unit (PCU) and containing the core and PCU in one vessel for the complete modularization. Authors noticed that the compressor and turbine assumed performances of KAIST MMR were conservatively selected previously. Thus, this paper tries to address the best estimate values of each turbomachinery in 10MWe class KAIST MMR. The turbomachinery size of the S-CO{sub 2} cycle is smaller than helium Brayton cycle and steam Rankine cycle. The suggested SMR concept adopts passive cooling system by using air. This method can cool reactor without external electricity supply. Small size and more flexible installation in the inland area will be necessary characteristics for the future nuclear application in the water limited region. KAIST MMR meets all these requirements by utilizing S-CO{sub 2} as a working fluid. This paper presents the work for further increasing the system performance by estimating the component efficiency more realistically. The cycle layout adopted for the application is S-CO{sub 2} recuperated Brayton cycle. The best efficiency of compressor and turbine was evaluated to be 84.94% and 90.94%, respectively. By using KAIST in-house code, thermal efficiency and net output were increased to 35.81% and 12.45MWe, respectively, for the same core thermal power. More refined cycle layout and suitable turbomachinery design will be performed in the near future.

  13. CO{sub 2} direct cycles suitable for AGR type reactors; Cycles directs de gaz carbonique applicables aux reacteurs du genre AGR

    Energy Technology Data Exchange (ETDEWEB)

    Maillet, E [Commissariat a l' Energie Atomique. Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

    1967-10-01

    The perspectives given by the gas turbines under pressure, to build simple nuclear power plants and acieving significantly high yield, are specified. The CO{sub 2} is characterised by by good efficiency under moderate temperature (500 to 750 Celsius degrees), compactness and the simpleness of machines and the safe exploitation (supply, storage, relief cooling, thermosyphon). The revision of thermal properties of the CO{sub 2} and loss elements show that several direct cycles would fit in particular to the AGR type reactors. Cycles that would diverge a little from classical models and able to lead to power and heat generation can lead by simple means to the best results. Several satisfying solutions present for the starting up, the power regulation and the stopping. The nuclear power plant components and the functioning safety are equally considered in the present report. The conclusions stimulate the studies and realizations of carbon dioxide gas turbines in when approprite. [French] Les perspectives offertes par la turbine a gaz sous pression, pour construire des centrales nucleaires simples et de rendement progressivement eleve, se precisent actuellement. le CO{sub 2} se distingue par sa bonne efficacite a temperature moderee (500 a 750 degres celsius), la compacite et la simplicite des machines, et la surete qu'il apporte a l'exploitation ( approvisionnement, stockage, refroidissement de secours, thermosiphon). La revision des proprietes thermophysiques du CO{sub 2} et des elements de pertes montre que divers cycles directs conviendraient en particulier aux reacteurs agr ou derives. Des cycles s'ecartant peu des modeles classiques, et se pretant ulterieurement a la production simultanee d'electricite et de chaleur, peuvent conduire par des moyens simples aux meilleurs resultats d'ensemble. Plusieurs solutions satisfaisantes se presentent pour le demarrage, le reglage de la puissance et l'arret. Les composants de la centrale et la surete de fonctionnement sont

  14. Life cycle analysis of advanced nuclear power generation technologies

    International Nuclear Information System (INIS)

    Uchiyama, Yoji; Yokoyama, Hayaichi

    1996-01-01

    In this research, as for light water reactors and fast breeder reactors, for the object of all the processes from the mining, transport and refining of fuel, electric power generation to the treatment and disposal of waste, the amount of energy input and the quantity of CO 2 emission over the life cycle were analyzed, and regarding the influence that the technical progress of nuclear power generation exerted to environment, the effect of improvement was elucidated. Attention has been paid to nuclear power generation as its CO 2 emission is least, and the effect of global warming is smallest. In order to reduce the quantity of radioactive waste generation in LWRs and the cost of fuel cycle, and to extend the operation cycle, the technical development for heightening fuel burnup is in progress. The process of investigation of the new technologies of nuclear power generation taken up in this research is described. The analysis of the energy balance of various power generation methods is discussed. In the case of pluthermal process, the improvement of energy balance ratio is dependent on uranium enrichment technology. Nuclear power generation requires much materials and energy for the construction, and emits CO 2 indirectly. The CO 2 unit emission based on the analysis of energy balance was determined for the new technologies of nuclear power generation, and the results are shown. (K.I.)

  15. Thermodynamic analysis of CO2 capture processes for power plants

    OpenAIRE

    Biyouki, Zeinab Amrollahi

    2014-01-01

    This thesis work presents an evaluation of various processes for reducing CO2 emissions from natural-gas-fired combined cycle (NGCC) power plants. The scope of the thesis is to focus mainly on post-combustion chemical absorption for NGCC. For the post-combustion capture plant, an important interface is the steam extraction from the steam turbine in order to supply the heat for solvent regeneration. The steam extraction imposes a power production penalty. The thesis includes analysis and compa...

  16. Factors influencing CO2 emissions in China's power industry: Co-integration analysis

    International Nuclear Information System (INIS)

    Zhao, Xiaoli; Ma, Qian; Yang, Rui

    2013-01-01

    More than 40% of China's total CO 2 emissions originate from the power industry. The realization of energy saving and emission reduction within China's power industry is therefore crucial in order to achieve CO 2 emissions reduction in this country. This paper applies the autoregressive-distributed lag (ARDL) co-integration model to study the major factors which have influenced CO 2 emissions within China's power industry from 1980 to 2010. Results have shown that CO 2 emissions from China's power industry have been increasing rapidly. From 1980 to 2010, the average annual growth rate was 8.5%, and the average growth rate since 2002 has amounted to 10.5%. Secondly, the equipment utilization hour (as an indicator of the power demand) has the greatest influence on CO 2 emissions within China's power industry. In addition, the impact of the industrial added value of the power sector on CO 2 emissions is also positive from a short-term perspective. Thirdly, the Granger causality results imply that one of the important motivators behind China's technological progress, within the power industry, originates from the pressures created by a desire for CO 2 emissions reduction. Finally, this paper provides policy recommendations for energy saving and emission reduction for China's power industry. - Highlights: ► We study the major factors influencing China's power industry CO 2 emissions. ► The average annual growth rate of CO 2 emission from power industry is calculated. ► Installed capacity has the greatest influence on power industry CO 2 emission. ► The Granger causality between CO 2 emission and its effecting factors is analyzed

  17. Control system options and strategies for supercritical CO2 cycles.

    Energy Technology Data Exchange (ETDEWEB)

    Moisseytsev, A.; Kulesza, K. P.; Sienicki, J. J.; Nuclear Engineering Division; Oregon State Univ.

    2009-06-18

    The Supercritical Carbon Dioxide (S-CO{sub 2}) Brayton Cycle is a promising alternative to Rankine steam cycle and recuperated gas Brayton cycle energy converters for use with Sodium-Cooled Fast Reactors (SFRs), Lead-Cooled Fast Reactors (LFRs), as well as other advanced reactor concepts. The S-CO{sub 2} Brayton Cycle offers higher plant efficiencies than Rankine or recuperated gas Brayton cycles operating at the same liquid metal reactor core outlet temperatures as well as reduced costs or size of key components especially the turbomachinery. A new Plant Dynamics Computer Code has been developed at Argonne National Laboratory for simulation of a S-CO{sub 2} Brayton Cycle energy converter coupled to an autonomous load following liquid metal-cooled fast reactor. The Plant Dynamics code has been applied to investigate the effectiveness of a control strategy for the S-CO{sub 2} Brayton Cycle for the STAR-LM 181 MWe (400 MWt) Lead-Cooled Fast Reactor. The strategy, which involves a combination of control mechanisms, is found to be effective for controlling the S-CO{sub 2} Brayton Cycle over the complete operating range from 0 to 100 % load for a representative set of transient load changes. While the system dynamic analysis of control strategy performance for STARLM is carried out for a S-CO{sub 2} Brayton Cycle energy converter incorporating an axial flow turbine and compressors, investigations of the S-CO{sub 2} Brayton Cycle have identified benefits from the use of centrifugal compressors which offer a wider operating range, greater stability near the critical point, and potentially further cost reductions due to fewer stages than axial flow compressors. Models have been developed at Argonne for the conceptual design and performance analysis of centrifugal compressors for use in the SCO{sub 2} Brayton Cycle. Steady state calculations demonstrate the wider operating range of centrifugal compressors versus axial compressors installed in a S-CO{sub 2} Brayton Cycle as

  18. Control system options and strategies for supercritical CO2 cycles

    International Nuclear Information System (INIS)

    Moisseytsev, A.; Kulesza, K.P.; Sienicki, J.J.

    2009-01-01

    The Supercritical Carbon Dioxide (S-CO 2 ) Brayton Cycle is a promising alternative to Rankine steam cycle and recuperated gas Brayton cycle energy converters for use with Sodium-Cooled Fast Reactors (SFRs), Lead-Cooled Fast Reactors (LFRs), as well as other advanced reactor concepts. The S-CO 2 Brayton Cycle offers higher plant efficiencies than Rankine or recuperated gas Brayton cycles operating at the same liquid metal reactor core outlet temperatures as well as reduced costs or size of key components especially the turbomachinery. A new Plant Dynamics Computer Code has been developed at Argonne National Laboratory for simulation of a S-CO 2 Brayton Cycle energy converter coupled to an autonomous load following liquid metal-cooled fast reactor. The Plant Dynamics code has been applied to investigate the effectiveness of a control strategy for the S-CO 2 Brayton Cycle for the STAR-LM 181 MWe (400 MWt) Lead-Cooled Fast Reactor. The strategy, which involves a combination of control mechanisms, is found to be effective for controlling the S-CO 2 Brayton Cycle over the complete operating range from 0 to 100 % load for a representative set of transient load changes. While the system dynamic analysis of control strategy performance for STARLM is carried out for a S-CO 2 Brayton Cycle energy converter incorporating an axial flow turbine and compressors, investigations of the S-CO 2 Brayton Cycle have identified benefits from the use of centrifugal compressors which offer a wider operating range, greater stability near the critical point, and potentially further cost reductions due to fewer stages than axial flow compressors. Models have been developed at Argonne for the conceptual design and performance analysis of centrifugal compressors for use in the SCO 2 Brayton Cycle. Steady state calculations demonstrate the wider operating range of centrifugal compressors versus axial compressors installed in a S-CO 2 Brayton Cycle as well as the benefits in expanding the range

  19. Performance analysis of solar parabolic trough collectors driven combined supercritical CO2 and organic Rankine cycle

    Directory of Open Access Journals (Sweden)

    Harwinder Singh

    2018-06-01

    Full Text Available In this paper, attempts have been made on the detailed energy and exergy analysis of solar parabolic trough collectors (SPTCs driven combined power plant. The combination of supercritical CO2 (SCO2 cycle and organic Rankine cycle (ORC integrated with SPTCs has been used to produce power, in which SCO2 cycle and ORC are arranged as a topping and bottoming cycle. Five organic working fluids like R134a, R1234yf, R407c, R1234ze, and R245fa were selected for a low temperature bottoming ORC. Five key exergetic parameters such as exergetic efficiency, exergy destruction rate, fuel depletion ratio, irreversibility ratio, and improvement potential were also examined. It was revealed that exergetic and thermal efficiency of all the combined cycles enhances as the direct normal irradiance increases from 0.5 kW/m2 to 0.95 kW/m2. As can be seen, R407c combined cycle has the maximum exergetic as well as thermal efficiency which is around 78.07% at 0.95 kW/m2 and 43.49% at 0.95 kW/m2, respectively. Alternatively, the R134a and R245fa combined cycle yields less promising results with the marginal difference in their performance. As inferred from the study that SCO2 turbine and evaporator has a certain amount of exergy destruction which is around 9.72% and 8.54% of the inlet exergy, and almost 38.10% of the total exergy destruction in case of R407c combined cycle. Moreover, the maximum amount of exergy destructed by the solar collector field which is more than 25% of the solar inlet exergy and around 54% of the total destructed exergy. Finally, this study concludes that R407c combined cycle has a minimum fuel depletion ratio of 0.2583 for a solar collector and possess the highest power output of 3740 kW. Keywords: Supercritical CO2cycle, Organic Rankine cycle, Exergetic performance, SPTCs, Organic fluids

  20. A Co-Powered Biomass and Concentrated Solar Power Rankine Cycle Concept for Small Size Combined Heat and Power Generation

    Directory of Open Access Journals (Sweden)

    Eileen Tortora

    2013-03-01

    Full Text Available The present work investigates the matching of an advanced small scale Combined Heat and Power (CHP Rankine cycle plant with end-user thermal and electric load. The power plant consists of a concentrated solar power field co-powered by a biomass furnace to produce steam in a Rankine cycle, with a CHP configuration. A hotel was selected as the end user due to its high thermal to electric consumption ratio. The power plant design and its operation were modelled and investigated by adopting transient simulations with an hourly distribution. The study of the load matching of the proposed renewable power technology and the final user has been carried out by comparing two different load tracking scenarios, i.e., the thermal and the electric demands. As a result, the power output follows fairly well the given load curves, supplying, on a selected winter day, about 50 GJ/d of thermal energy and the 6 GJ/d of electric energy, with reduced energy dumps when matching the load.

  1. CO{sub 2} emissions - sequestration, costs; Emisja CO{sub 2} - sekwestracja, koszty

    Energy Technology Data Exchange (ETDEWEB)

    Rakowski, J. [Inst. of Power Industry, Warsaw (Poland). Thermal Process Department

    2004-07-01

    The paper discusses and compares costs of technologies for limiting emissions of carbon dioxide in both before and after combustion in power generation - natural gas combined cycle; coal power unit with pulverised fuel boiler at both supercritical conditions and ultra supercritical conditions; and integrated gasification combined cycle. It then discusses in some detail the concept of an IGCC unit adapted to the removal of CO{sub 2} with the simultaneous production of hydrogen, and the use of an oxygen plant with CO{sub 2} recycling. 17 refs., 2 figs., 10 tabs.

  2. Analysis of a novel solar energy-powered Rankine cycle for combined power and heat generation using supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.R.; Yamaguchi, H.; Uneno, D. [Department of Mechanical Engineering, Doshisha University, Kyoto 630-0321 (Japan); Fujima, K. [Mayekawa MFG Co., Ltd., 2000 Tatsuzawa Moriya-city, Ibaraki-Pref. 302-0118 (Japan); Enomoto, M. [Showa Denko K. K., 1-480, Inuzuka, Oyama-city, Tochigi 323-8679 (Japan); Sawada, N. [Showa Tansan Co., Ltd., 7-1, Ogimachi, Kawasaki-Ku, Kawasaki-city, Kanagawa 210-0867 (Japan)

    2006-10-15

    Theoretical analysis of a solar energy-powered Rankine thermodynamic cycle utilizing an innovative new concept, which uses supercritical carbon dioxide as a working fluid, is presented. In this system, a truly 'natural' working fluid, carbon dioxide, is utilized to generate firstly electricity power and secondly high-grade heat power and low-grade heat power. The uniqueness of the system is in the way in which both solar energy and carbon dioxide, available in abundant quantities in all parts of the world, are simultaneously used to build up a thermodynamic cycle and has the potential to reduce energy shortage and greatly reduce carbon dioxide emissions and global warming, offering environmental and personal safety simultaneously. The system consists of an evacuated solar collector system, a power-generating turbine, a high-grade heat recovery system, a low-grade heat recovery system and a feed pump. The performances of this CO{sub 2}-based Rankine cycle were theoretically investigated and the effects of various design conditions, namely, solar radiation, solar collector area and CO{sub 2} flow rate, were studied. Numerical simulations show that the proposed system may have electricity power efficiency and heat power efficiency as high as 11.4% and 36.2%, respectively. It is also found that the cycle performances strongly depend on climate conditions. Also the electricity power and heat power outputs increase with the collector area and CO{sub 2} flow rate. The estimated COP{sub power} and COP{sub heat} increase with the CO{sub 2} flow rate, but decrease with the collector area. The CO{sub 2}-based cycle can be optimized to provide maximum power, maximum heat recovery or a combination of both. The results suggest the potential of this new concept for applications to electricity power and heat power generation. (author)

  3. Life cycle assessment of sewage sludge co-incineration in a coal-based power station.

    Science.gov (United States)

    Hong, Jingmin; Xu, Changqing; Hong, Jinglan; Tan, Xianfeng; Chen, Wei

    2013-09-01

    A life cycle assessment was conducted to evaluate the environmental and economic effects of sewage sludge co-incineration in a coal-fired power plant. The general approach employed by a coal-fired power plant was also assessed as control. Sewage sludge co-incineration technology causes greater environmental burden than does coal-based energy production technology because of the additional electricity consumption and wastewater treatment required for the pretreatment of sewage sludge, direct emissions from sludge incineration, and incinerated ash disposal processes. However, sewage sludge co-incineration presents higher economic benefits because of electricity subsidies and the income generating potential of sludge. Environmental assessment results indicate that sewage sludge co-incineration is unsuitable for mitigating the increasing pressure brought on by sewage sludge pollution. Reducing the overall environmental effect of sludge co-incineration power stations necessitates increasing net coal consumption efficiency, incinerated ash reuse rate, dedust system efficiency, and sludge water content rate. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Supercritical CO2 Compressor with Active Magnetic Bearing

    International Nuclear Information System (INIS)

    Cha, Jae Eun; Cho, Seong Kuk; Lee, JeKyoung; Lee, Jeong Ik

    2016-01-01

    For the stable operation of the sCO 2 integral test facility SCIEL, KAERI prepared Active Magnetic Bearing sCO 2 compressor for the 70,000RPM operation. Power generation test with AMB compressor will be finished within first half year of 2016 under supercritical state. The principal advantages of the sCO 2 Cycle are high efficiency at moderate temperature range, compact components size, simple cycle configuration, and compatibility with various heat sources. The Supercritical CO 2 Brayton Cycle Integral Experiment Loop (SCIEL) has been installed in Korea Atomic Energy Research Institute (KAERI) to develop the base technologies for the sCO 2 cycle power generation system. The operation of the SCIEL has mainly focused on sCO 2 compressor development and establishing sCO 2 system control logic

  5. Exergy and exergoeconomic analyses of a supercritical CO_2 cycle for a cogeneration application

    International Nuclear Information System (INIS)

    Wang, Xurong; Yang, Yi; Zheng, Ya; Dai, Yiping

    2017-01-01

    Detailed exergy and exergoeconomic analyses are performed for a combined cogeneration cycle in which the waste heat from a recompression supercritical CO_2 Brayton cycle (sCO_2) is recovered by a transcritical CO_2 cycle (tCO_2) for generating electricity. Thermodynamic and exergoeconomic models are developed on the basis of mass and energy conservations, exergy balance and exergy cost equations. Parametric investigations are then conducted to evaluate the influence of key decision variables on the sCO_2/tCO_2 performance. Finally, the combined cycle is optimized from the viewpoint of exergoeconomics. It is found that, combining the sCO_2 with a tCO_2 cycle not only enhances the energy and exergy efficiencies of the sCO_2, but also improves the cycle exergoeconomic performance. The results show that the most exergy destruction rate takes place in the reactor, and the components of the tCO_2 bottoming cycle have less exergy destruction. When the optimization is conducted based on the exergoeconomics, the overall exergoeconomic factor, the total cost rate and the exergy destruction cost rate are 53.52%, 11243.15 $/h and 5225.17 $/h, respectively. The optimization study reveals that an increase in reactor outlet temperature leads to a decrease in total cost rate and total exergy destruction cost rate of the system. - Highlights: • Exergy and exergoeconomic analyses of a combined sCO_2/tCO_2 cycle were performed. • Exergoeconomic optimization of the sCO_2/tCO_2 cycle was presented. • The reactor had the highest exergy loss among sCO_2/tCO_2 cycle components. • The overall exergoeconomic factor was up to 53.5% for the optimum case.

  6. Energy-water nexus of wind power in China: The balancing act between CO2 emissions and water consumption

    International Nuclear Information System (INIS)

    Li Xin; Feng Kuishuang; Siu, Yim Ling; Hubacek, Klaus

    2012-01-01

    At the end of 2010, China's contribution to global CO 2 emissions reached 25.1%. Estimates show that power generation accounts for 37.2% of the Chinese CO 2 emissions. Even though there is an increasing number of studies using life cycle analysis (LCA) to examine energy consumption and CO 2 emissions required by different types of power generation technologies, there are very few studies focusing on China. Furthermore, the nexus between water consumption and energy production has largely been ignored. In this paper, we adopt input–output based hybrid life cycle analysis to evaluate water consumption and CO 2 emissions of wind power in China. Our results show that China's wind energy consumes 0.64 l/kWh of water and produces 69.9 g/kWh of CO 2 emission. Given that the Chinese government aims to increase the wind power generation capacity to 200 GW by 2020, wind power could contribute a 23% reduction in carbon intensity and could save 800 million m 3 of water which could be sufficient enough for use by 11.2 million households. Thus, given the often postulated water crisis, China's energy policy would reap double benefits through progressive energy policies when increasing the share of wind power as part of overall efforts to diversify its electricity generation technologies. - Highlights: ► The nexus of water consumption and CO 2 emission of China's wind power is examined. ► Wind power consumes 0.64 l/kWh of water and produces 69.9 g/kWh of CO 2 . ► Wind power could save 800 million m 3 of water for use by 11.2 million households. ► Wind power could contribute 23% of China's carbon intensity target by 2020. ► Wind power deemed to be a viable means of achieving carbon and water savings.

  7. Economical analysis of an alternative strategy for CO2 mitigation based on nuclear power

    International Nuclear Information System (INIS)

    Alonso, Gustavo; Valle, Edmundo del

    2013-01-01

    Many countries are pursuing greenhouse gas (GHG) mitigation policies resulting in the increase of use of renewable sources in the electricity sector to mitigate CO 2 emissions. Nuclear energy is a non-emitting CO 2 source that could be used as part of that policy. However, its main drawback is the high investment required for its deployment. On the other hand, wind power is the clean source preferred option to mitigate CO 2 emissions. However, due to its intermittence backup power is needed, in most of the cases it must be provided with combined cycle thermal plants using natural gas. This study performs an economical comparison of a hypothetical implementation of a nuclear strategy to meet the same CO 2 emissions reduction goal that has been obtained by the actual Spaniard strategy (2005–2010) based on wind power. The investment required in both strategies is assessed under different investment scenarios and electricity production conditions for nuclear power. Also, the cost of electricity generation is compared for both strategies. - Highlights: ► Wind power electricity cost including its backup in Spain is assessed. ► Nuclear power is proposed as an alternative to produce the same CO 2 reduction. ► Nuclear power requires less installed capacity deployment. ► Investment to produce the same CO 2 reduction is smaller using nuclear power. ► Electricity generating cost is less expensive using the nuclear option

  8. CO{sub 2} control technologies: ALSTOM Power approach

    Energy Technology Data Exchange (ETDEWEB)

    Stamatelopoulos, G.N.; Marion, J.L.; Nsakala, N.; Griffin, T.; Bill, A. [ALSTOM Power Boiler GmbH, Stuttgart (Germany)

    2002-07-01

    ALSTOM Power is one of the largest providers of power generation equipment, turnkey power plants and services in the world. The Company is aware of the present scientific concerns regarding greenhouse gas emissions and the role of fossil fuels used in power generation. ALSTOM Power R&D laboratories run various programs aiming to find options that reduce greenhouse gas emissions through: Increasing the efficiency of power generation equipment by implementing the most modern technologies. Application of technologies to remove and sequester carbon dioxide created in power plants in an environmentally and economically favorable manner. In this paper an overview of ALSTOM's on-going CO{sub 2} mitigation development activities will be presented. First, energy efficiency improvements for both new and existing fossil fuel power plants are reviewed for both coal and natural gas fuels. Second, the development of novel power generation processes, including those involving combustion in O{sub 2}/CO{sub 2} atmospheres using pure or enriched oxygen for the purpose of CO{sub 2} capture is discussed. And finally, novel chemical-looping CO{sub 2} capture process technologies are introduced. The major challenge in CO{sub 2} capture techniques is the efficient separation and capture of CO{sub 2}. Conclusions are drawn herein regarding the technical feasibility, the resultant efficiency penalties, and the CO{sub 2} mitigation costs for the various options under study and development within ALSTOM Power. 7 refs., 8 figs.

  9. Description of Supercritical CO{sub 2} Compressor Experiment Loop

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Je Kyoung; Lee, Jeong Ik; Ahn, Yoonhan; Kim, Seong Gu [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Cha, Je Eun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    The full scope of SCIEL project is to demonstrate high efficiency with simple recuperated cycle layout or recompressing layout, which the final cycle layout will be determined by the obtained compressor performance data. As a part of SCIEL project, S-CO{sub 2} compressor experiment facility has been constructed in KAERI. In this paper, current status of S-CO{sub 2} compressor experiment loop will be reviewed. With the growing interest in developing an advanced nuclear power plant, power conversion cycle innovation has been the part of this effort to secure high economics and enhanced safety. One of the main activities of power conversion cycle innovation is the development of Supercritical CO{sub 2} Brayton cycle technology. S-CO{sub 2} Brayton cycle concept was suggested in 1960s but the development and realization of the technology has been delayed up to now. In Korea, KAIST, KAERI and POSTECH are conducting research and development of Korean S-CO{sub 2} Brayton cycle technology by erecting the Supercritical CO{sub 2} Integral Experiment Loop (SCIEL)

  10. Evaluation and optimization of a supercritical carbon dioxide power conversion cycle for nuclear applications

    International Nuclear Information System (INIS)

    Harvego, Edwin A.; McKellar, Michael G.

    2011-01-01

    There have been a number of studies involving the use of gases operating in the supercritical mode for power production and process heat applications. Supercritical carbon dioxide (CO 2 ) is particularly attractive because it is capable of achieving relatively high power conversion cycle efficiencies in the temperature range between 550degC and 750degC. Therefore, it has the potential for use with any type of high-temperature nuclear reactor concept, assuming reactor core outlet temperatures of at least 550degC. The particular power cycle investigated in this paper is a supercritical CO 2 recompression Brayton Cycle. The CO 2 recompression Brayton Cycle can be used as either a direct or indirect power conversion cycle, depending on the reactor type and reactor outlet temperature. The advantage of this cycle when compared to the helium Brayton Cycle is the lower required operating temperature; 550degC versus 750degC. However, the supercritical CO 2 recompression Brayton Cycle requires a high end operating pressure in the range of 20 MPa, which is considerably higher than the required helium Brayton cycle high end operating pressure of 7 MPa. This paper presents results of analyses performed using the UniSim process analyses software to evaluate the performance of the supercritical CO 2 recompression Brayton cycle for different reactor coolant outlet temperatures and mass flow rates. The UniSim model assumed a 600 MWt reactor power source, which provides heat to the power cycle at a maximum temperature of between 550degC and 850degC. Sensitivity calculations were also performed to determine the affect of reactor coolant mass flow rates for a reference reactor coolant outlet temperature of 750degC. The UniSim model used realistic component parameters and operating conditions to model the complete power conversion system. CO 2 properties were evaluated, and the operating range for the cycle was adjusted to take advantage of the rapidly changing conditions near the

  11. Design Study of Supercritical CO{sub 2} Integral Experiment Loop (SCIEL)

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Yoonhan; Lee, Jaekyoung; Lee, Jeong Ik [Korea Adavanced Institute of Science and Technology, Daejeon (Korea, Republic of); Cha, Jae Eun [Korean Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    As the global warming becomes more substantial, the development of highly efficient power conversion system gains a lot of interests to reduce CO{sub 2} emission. Supercritical CO{sub 2} (S-CO{sub 2}) cycle is considered as one of the promising candidates due to the competitive efficiency in the mild turbine inlet temperature range, and the compact footprint with compact turbomachinery and heat exchangers. With these advantages, S-CO{sub 2} cycle can be utilized as the power conversion system of fossil power, advanced nuclear reactor, renewable energy system and a bottoming cycle for gas turbine or high temperature fuel cell, as well. In addition, the S-CO{sub 2} cycle is considered as the alternative power conversion system of a Sodium-cooled Fast Reactor (SFR) as the violent Sodium-Water Reaction (SWR) can be replaced with the mild Sodium-CO{sub 2} Reaction (SCR). To demonstrate the S-CO{sub 2} cycle performance, the integral test facilities were constructed and the operational results were reported by several countries. The development of S-CO{sub 2} cycle can be utilized as the power conversion system including the fossil power, next generation nuclear reactor, and concentrated solar power systems as the cycle efficiency is high in the mild turbine inlet temperature range (450-650 .deg. C) and the layout is simple with the physically compact system size. To demonstrate the S-CO{sub 2} cycle performance, Supercritical CO{sub 2} Integral Experiment Loop (SCIEL) has been under development by the joint research team of KAERI, KAIST and POSTECH. The final layout of SCIEL is recuperated cycle with a double stage of compression and expansion to achieve 2.57 pressure ratio. Considering the temperature difference limit of PCHE, a series of recuperation process is utilized.

  12. Exergy Analysis of a Syngas-Fueled Combined Cycle with Chemical-Looping Combustion and CO2 Sequestration

    Directory of Open Access Journals (Sweden)

    Álvaro Urdiales Montesino

    2016-08-01

    Full Text Available Fossil fuels are still widely used for power generation. Nevertheless, it is possible to attain a short- and medium-term substantial reduction of greenhouse gas emissions to the atmosphere through a sequestration of the CO2 produced in fuels’ oxidation. The chemical-looping combustion (CLC technique is based on a chemical intermediate agent, which gets oxidized in an air reactor and is then conducted to a separated fuel reactor, where it oxidizes the fuel in turn. Thus, the oxidation products CO2 and H2O are obtained in an output flow in which the only non-condensable gas is CO2, allowing the subsequent sequestration of CO2 without an energy penalty. Furthermore, with shrewd configurations, a lower exergy destruction in the combustion chemical transformation can be achieved. This paper focus on a second law analysis of a CLC combined cycle power plant with CO2 sequestration using syngas from coal and biomass gasification as fuel. The key thermodynamic parameters are optimized via the exergy method. The proposed power plant configuration is compared with a similar gas turbine system with a conventional combustion, finding a notable increase of the power plant efficiency. Furthermore, the influence of syngas composition on the results is investigated by considering different H2-content fuels.

  13. Design analysis of a lead–lithium/supercritical CO2 Printed Circuit Heat Exchanger for primary power recovery

    International Nuclear Information System (INIS)

    Fernández, Iván; Sedano, Luis

    2013-01-01

    Highlights: • A design for a PbLi/CO 2 (SC) Printed Circuit Heat Exchanger which optimizes the pressure drop performance is proposed. • Numerical analyses have been performed to optimize the airfoil fins shape and arrangement. • SiC is proposed as structural material and tritium permeation barrier for the PCHE. • The integrated flux is larger than expected and allows reducing the CO 2 mass flow in this sector of the power cycle. • A transport model has been developed to evaluate the permeation of tritium from the liquid metal to the secondary CO 2 . -- Abstract: One of the key issues for fusion power plant technology is the efficient, reliable and safe recovery of the power extracted by the primary coolants. An interesting design option for power conversion cycles based on Dual Coolant Breeding Blankets (DCBB) is a Printed Circuit Heat Exchanger, which is supported by the advantages of its compactness, thermal effectiveness, high temperature and pressure capability and corrosion resistance. This work presents a design analysis of a silicon carbide Printed Circuit Heat Exchanger for lead–lithium/supercritical CO 2 at DEMO ranges (4× segmentation)

  14. Membranes for H2 generation from nuclear powered thermochemical cycles

    International Nuclear Information System (INIS)

    Nenoff, Tina Maria; Ambrosini, Andrea; Garino, Terry J.; Gelbard, Fred; Leung, Kevin; Navrotsky, Alexandra; Iyer, Ratnasabapathy G.; Axness, Marlene

    2006-01-01

    In an effort to produce hydrogen without the unwanted greenhouse gas byproducts, high-temperature thermochemical cycles driven by heat from solar energy or next-generation nuclear power plants are being explored. The process being developed is the thermochemical production of Hydrogen. The Sulfur-Iodide (SI) cycle was deemed to be one of the most promising cycles to explore. The first step of the SI cycle involves the decomposition of H 2 SO 4 into O 2 , SO 2 , and H 2 O at temperatures around 850 C. In-situ removal of O 2 from this reaction pushes the equilibrium towards dissociation, thus increasing the overall efficiency of the decomposition reaction. A membrane is required for this oxygen separation step that is capable of withstanding the high temperatures and corrosive conditions inherent in this process. Mixed ionic-electronic perovskites and perovskite-related structures are potential materials for oxygen separation membranes owing to their robustness, ability to form dense ceramics, capacity to stabilize oxygen nonstoichiometry, and mixed ionic/electronic conductivity. Two oxide families with promising results were studied: the double-substituted perovskite A x Sr 1-x Co 1-y B y O 3-δ (A=La, Y; B=Cr-Ni), in particular the family La x Sr 1-x Co 1-y Mn y O 3-δ (LSCM), and doped La 2 Ni 1-x M x O 4 (M = Cu, Zn). Materials and membranes were synthesized by solid state methods and characterized by X-ray and neutron diffraction, SEM, thermal analyses, calorimetry and conductivity. Furthermore, we were able to leverage our program with a DOE/NE sponsored H 2 SO 4 decomposition reactor study (at Sandia), in which our membranes were tested in the actual H 2 SO 4 decomposition step

  15. Methodology of CO{sub 2} emission evaluation in the life cycle of office building facades

    Energy Technology Data Exchange (ETDEWEB)

    Taborianski, Vanessa Montoro; Prado, Racine T.A., E-mail: racine.prado@poli.usp.br

    2012-02-15

    The construction industry is one of the greatest sources of pollution because of the high level of energy consumption during its life cycle. In addition to using energy while constructing a building, several systems also use power while the building is operating, especially the air-conditioning system. Energy consumption for this system is related, among other issues, to external air temperature and the required internal temperature of the building. The facades are elements which present the highest level of ambient heat transfer from the outside to the inside of tall buildings. Thus, the type of facade has an influence on energy consumption during the building life cycle and, consequently, contributes to buildings' CO{sub 2} emissions, because these emissions are directly connected to energy consumption. Therefore, the aim is to help develop a methodology for evaluating CO{sub 2} emissions generated during the life cycle of office building facades. The results, based on the parameters used in this study, show that facades using structural glazing and uncolored glass emit the most CO{sub 2} throughout their life cycle, followed by brick facades covered with compound aluminum panels or ACM (Aluminum Composite Material), facades using structural glazing and reflective glass and brick facades with plaster coating. On the other hand, the typology of facade that emits less CO{sub 2} is brickwork and mortar because its thermal barrier is better than structural glazing facade and materials used to produce this facade are better than brickwork and ACM. Finally, an uncertainty analysis was conducted to verify the accuracy of the results attained. - Highlights: Black-Right-Pointing-Pointer We develop a methodology for evaluating CO{sub 2} emissions generated during the life cycle of office building facades. Black-Right-Pointing-Pointer This methodology is based in LCA. Black-Right-Pointing-Pointer We use an uncertainty analysis to verify the accuracy of the results

  16. High-Efficiency Low-Cost Solar Receiver for Use Ina a Supercritical CO2 Recompression Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, Shaun D. [Brayton Energy, LLC, Portsmouth, NH (United States); Kesseli, James [Brayton Energy, LLC, Portsmouth, NH (United States); Nash, James [Brayton Energy, LLC, Portsmouth, NH (United States); Farias, Jason [Brayton Energy, LLC, Portsmouth, NH (United States); Kesseli, Devon [Brayton Energy, LLC, Portsmouth, NH (United States); Caruso, William [Brayton Energy, LLC, Portsmouth, NH (United States)

    2016-04-06

    This project has performed solar receiver designs for two supercritical carbon dioxide (sCO2) power cycles. The first half of the program focused on a nominally 2 MWe power cycle, with a receiver designed for test at the Sandia Solar Thermal Test Facility. This led to an economical cavity-type receiver. The second half of the program focused on a 10 MWe power cycle, incorporating a surround open receiver. Rigorous component life and performance testing was performed in support of both receiver designs. The receiver performance objectives are set to conform to the US DOE goals of 6¢/kWh by 2020 . Key findings for both cavity-type and direct open receiver are highlighted below: A tube-based absorber design is impractical at specified temperatures, pressures and heat fluxes for the application; a plate-fin architecture however has been shown to meet performance and life targets; the $148/kWth cost of the design is significantly less than the SunShot cost target with a margin of 30%; the proposed receiver design is scalable, and may be applied to both modular cavity-type installations as well as large utility-scale open receiver installations; the design may be integrated with thermal storage systems, allowing for continuous high-efficiency electrical production during off-sun hours; costs associated with a direct sCO2 receiver for a sCO2 Brayton power cycle are comparable to those of a typical molten salt receiver; lifetimes in excess of the 90,000 hour goal are achievable with an optimal cell geometry; the thermal performance of the Brayton receiver is significantly higher than the industry standard, and enables at least a 30% efficiency improvement over the performance of the baseline steam-Rankine boiler/cycle system; brayton’s patent-pending quartz tube window provides a greater than five-percent efficiency benefit to the receiver by reducing both convection and radiation losses.

  17. Supercritical CO{sub 2} Compressor with Active Magnetic Bearing

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Jae Eun [KAERI, Daejeon (Korea, Republic of); Cho, Seong Kuk; Lee, JeKyoung; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    For the stable operation of the sCO{sub 2} integral test facility SCIEL, KAERI prepared Active Magnetic Bearing sCO{sub 2} compressor for the 70,000RPM operation. Power generation test with AMB compressor will be finished within first half year of 2016 under supercritical state. The principal advantages of the sCO{sub 2} Cycle are high efficiency at moderate temperature range, compact components size, simple cycle configuration, and compatibility with various heat sources. The Supercritical CO{sub 2} Brayton Cycle Integral Experiment Loop (SCIEL) has been installed in Korea Atomic Energy Research Institute (KAERI) to develop the base technologies for the sCO{sub 2} cycle power generation system. The operation of the SCIEL has mainly focused on sCO{sub 2} compressor development and establishing sCO{sub 2} system control logic.

  18. Power conversion systems based on Brayton cycles for fusion reactors

    International Nuclear Information System (INIS)

    Linares, J.I.; Herranz, L.E.; Moratilla, B.Y.; Serrano, I.P.

    2011-01-01

    This paper investigates Brayton power cycles for fusion reactors. Two working fluids have been explored: helium in classical configurations and CO 2 in recompression layouts (Feher cycle). Typical recuperator arrangements in both cycles have been strongly constrained by low temperature of some of the energy thermal sources from the reactor. This limitation has been overcome in two ways: with a combined architecture and with dual cycles. Combined architecture couples the Brayton cycle with a Rankine one capable of taking advantage of the thermal energy content of the working fluid after exiting the turbine stage (iso-butane and steam fitted best the conditions of the He and CO 2 cycles, respectively). Dual cycles set a specific Rankine cycle to exploit the lowest quality thermal energy source, allowing usual recuperator arrangements in the Brayton cycle. The results of the analyses indicate that dual cycles could reach thermal efficiencies around 42.8% when using helium, whereas thermal performance might be even better (46.7%), if a combined CO 2 -H 2 O cycle was set.

  19. Cycle development and design for CO2 capture from flue gas by vacuum swing adsorption.

    Science.gov (United States)

    Zhang, Jun; Webley, Paul A

    2008-01-15

    CO2 capture and storage is an important component in the development of clean power generation processes. One CO2 capture technology is gas-phase adsorption, specifically pressure (or vacuum) swing adsorption. The complexity of these processes makes evaluation and assessment of new adsorbents difficult and time-consuming. In this study, we have developed a simple model specifically targeted at CO2 capture by pressure swing adsorption and validated our model by comparison with data from a fully instrumented pilot-scale pressure swing adsorption process. The model captures nonisothermal effects as well as nonlinear adsorption and nitrogen coadsorption. Using the model and our apparatus, we have designed and studied a large number of cycles for CO2 capture. We demonstrate that by careful management of adsorption fronts and assembly of cycles based on understanding of the roles of individual steps, we are able to quickly assess the effect of adsorbents and process parameters on capture performance and identify optimal operating regimes and cycles. We recommend this approach in contrast to exhaustive parametric studies which tend to depend on specifics of the chosen cycle and adsorbent. We show that appropriate combinations of process steps can yield excellent process performance and demonstrate how the pressure drop, and heat loss, etc. affect process performance through their effect on adsorption fronts and profiles. Finally, cyclic temperature profiles along the adsorption column can be readily used to infer concentration profiles-this has proved to be a very useful tool in cyclic function definition. Our research reveals excellent promise for the application of pressure/vacuum swing adsorption technology in the arena of CO2 capture from flue gases.

  20. Life cycle GHG assessment of fossil fuel power plants with carbon capture and storage

    International Nuclear Information System (INIS)

    Odeh, Naser A.; Cockerill, Timothy T.

    2008-01-01

    The evaluation of life cycle greenhouse gas emissions from power generation with carbon capture and storage (CCS) is a critical factor in energy and policy analysis. The current paper examines life cycle emissions from three types of fossil-fuel-based power plants, namely supercritical pulverized coal (super-PC), natural gas combined cycle (NGCC) and integrated gasification combined cycle (IGCC), with and without CCS. Results show that, for a 90% CO 2 capture efficiency, life cycle GHG emissions are reduced by 75-84% depending on what technology is used. With GHG emissions less than 170 g/kWh, IGCC technology is found to be favorable to NGCC with CCS. Sensitivity analysis reveals that, for coal power plants, varying the CO 2 capture efficiency and the coal transport distance has a more pronounced effect on life cycle GHG emissions than changing the length of CO 2 transport pipeline. Finally, it is concluded from the current study that while the global warming potential is reduced when MEA-based CO 2 capture is employed, the increase in other air pollutants such as NO x and NH 3 leads to higher eutrophication and acidification potentials

  1. Technical comparison between Integrated Gasification Combined Cycle (IGCC) and Natural Gas Combined Cycle (NGCC) power plants

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, Pablo Andres Silva; Venturini, Osvaldo Jose; Lora, Electo Eduardo Silva [Federal University of Itajuba - UNIFEI, MG (Brazil). Excellence Group in Thermal Power and Distributed Generation - NEST], e-mails: osvaldo@unifei.edu.br, electo@unifei.edu.br

    2010-07-01

    Among the emerging clean coal technologies for power generation, Integrated Gasification Combined Cycle (IGCC) and Natural Gas Combined Cycle (NGCC) systems are receiving considerable attention as a potentially attractive option to reduce the emissions of greenhouse gases (GHG). The main reason is because these systems has high efficiency and low emissions in comparison with traditional power generation plants. Currently in IGCC and NGCC systems at demonstration stage is been considered to implement CCS technology. CO{sub 2} emissions can be avoided in a gasification-based power plant because by transferring almost all carbon compounds to CO{sub 2} through the water gas shift (WGS) reaction, then removing the CO{sub 2} before it is diluted in the combustion stage. The aim of this study is to compare the technical performance of an IGCC system that uses Brazilian coal and petroleum coke as fuel with a NGCC system, with the same fixed output power of 450 MW. The first section of this paper presents the plant configurations of IGCC systems. The following section presents an analysis of NGCC technology. (author)

  2. Potential advantages of coupling supercritical CO2 Brayton cycle to water cooled small and medium size reactor

    International Nuclear Information System (INIS)

    Yoon, Ho Joon; Ahn, Yoonhan; Lee, Jeong Ik; Addad, Yacine

    2012-01-01

    Highlights: ► S-CO 2 cycle as candidate for SMS. ► MATLAB code used for S-CO 2 cycle analysis. ► Pressure ratio and split ratio comparison analyzed. - Abstract: The supercritical carbon dioxide (S-CO 2 ) Brayton cycle is being considered as a favorable candidate for the next generation nuclear reactors power conversion systems. Major benefits of the S-CO 2 Brayton cycle compared to other Brayton cycles are: (1) high thermal efficiency in relatively low turbine inlet temperature, (2) compactness of the turbomachineries and heat exchangers and (3) simpler cycle layout at an equivalent or superior thermal efficiency. However, these benefits can be still utilized even in the water-cooled reactor technologies under special circumstances. A small and medium size water-cooled nuclear reactor (SMR) has been gaining interest due to its wide range of application such as electricity generation, seawater desalination, district heating and propulsion. Another key advantage of a SMR is that it can be transported from one place to another mostly by maritime transport due to its small size, and sometimes even through a railway system. Therefore, the combination of a S-CO 2 Brayton cycle with a SMR can reinforce any advantages coming from its small size if the S-CO 2 Brayton cycle has much smaller size components, and simpler cycle layout compared to the currently considered steam Rankine cycle. In this paper, SMART (System-integrated Modular Advanced ReacTor), a 330 MW th integral reactor developed by KAERI (Korea Atomic Energy Institute) for multipurpose utilization, is considered as a potential candidate for applying the S-CO 2 Brayton cycle and advantages and disadvantages of the proposed system will be discussed in detail. In consideration of SMART condition, the turbine inlet pressure and size of heat exchangers are analyzed by using in-house code developed by KAIST–Khalifa University joint research team. According to the cycle evaluation, the maximum cycle efficiency

  3. Life cycle analysis of geothermal power generation with supercritical carbon dioxide

    International Nuclear Information System (INIS)

    Frank, Edward D; Sullivan, John L; Wang, Michael Q

    2012-01-01

    Life cycle analysis methods were employed to model the greenhouse gas emissions and fossil energy consumption associated with geothermal power production when supercritical carbon dioxide (scCO 2 ) is used instead of saline geofluids to recover heat from below ground. Since a significant amount of scCO 2 is sequestered below ground in the process, a constant supply is required. We therefore combined the scCO 2 geothermal power plant with an upstream coal power plant that captured a portion of its CO 2 emissions, compressed it to scCO 2 , and transported the scCO 2 by pipeline to the geothermal power plant. Emissions and energy consumption from all operations spanning coal mining and plant construction through power production were considered, including increases in coal use to meet steam demand for the carbon capture. The results indicated that the electricity produced by the geothermal plant more than balanced the increase in energy use resulting from carbon capture at the coal power plant. The effective heat rate (BTU coal per total kW h of electricity generated, coal plus geothermal) was comparable to that of traditional coal, but the ratio of life cycle emissions from the combined system to that of traditional coal was 15% when 90% carbon capture efficiency was assumed and when leakage from the surface was neglected. Contributions from surface leakage were estimated with a simple model for several hypothetical surface leakage rates. (letter)

  4. Optimization of a recompression supercritical carbon dioxide cycle for an innovative central receiver solar power plant

    International Nuclear Information System (INIS)

    Reyes-Belmonte, M.A.; Sebastián, A.; Romero, M.; González-Aguilar, J.

    2016-01-01

    Peculiar thermodynamic properties of carbon dioxide (CO 2 ) when it is held at or above its critical condition (stated as supercritical CO 2 or sCO 2 ) have attracted the attention of many researchers. Its excellent thermophysical properties at medium-to-moderate temperature range have made it to be considered as the alternative working fluid for next power plant generation. Among those applications, future nuclear reactors, solar concentrated thermal energy or waste energy recovery have been shown as the most promising ones. In this paper, a recompression sCO 2 cycle for a solar central particles receiver application has been optimized, observing net cycle efficiency close to 50%. However, small changes on cycle parameters such as working temperatures, recuperators efficiencies or mass flow distribution between low and high temperature recuperators were found to drastically modify system overall efficiency. In order to mitigate these uncertainties, an optimization analysis based on recuperators effectiveness definition was performed observing that cycle efficiency could lie among 40%–50% for medium-to-moderate temperature range of the studied application (630 °C–680 °C). Due to the lack of maturity of current sCO 2 technologies and no power production scale demonstrators, cycle boundary conditions based on the solar application and a detailed literature review were chosen. - Highlights: • Mathematical modelling description for recompression sCO 2 cycle. • Split fraction and recuperators effectiveness effect into sCO 2 cycle performance. • Optimization methodology of sCO 2 cycle for an innovative solar central receiver. • Power generation using particles central receiver.

  5. Report on studies on closed cycle MHD power generation; Closed cycle MHD hatsuden kento hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1991-04-01

    Summarized herein are results of the studies on closed cycle MHD (CCMHD) power generation by the study committee. The studied system is based on the MHD gas turbine combined Brayton cycle of about 500,000 kW in output power, firing natural gas as the fuel, and the conceptual design works therefor are completed. The major findings are: the overall plant efficiency: 54.2% at the power transmission side, plot area required per unit power output: 0.04 m{sup 2}/KW, unit construction cost: 251,000 yen/KW, and unit power generation cost: 10.2 yen/KWh. This system will be more operable than the gas turbine combined cycle with steam system, because start-up time, output change rate, optimum load and so on are constrained not on the power generator side but on the gas turbine side. The expected environmental effects include the exhaust gas NOX concentration being equivalent with that associated with the conventional power generator of 2-stage combustion system, quantity of combustion gases to be treated being approximately 40% of that associated with the gas turbine combined cycle, and reduced CO2 gas emissions, resulting from enhanced power generation efficiency. It is expected that the CCMHD system can exhibit higher efficiency than the high-temperature gas turbine combined cycle system. (NEDO)

  6. Membranes for H2 generation from nuclear powered thermochemical cycles.

    Energy Technology Data Exchange (ETDEWEB)

    Nenoff, Tina Maria; Ambrosini, Andrea; Garino, Terry J.; Gelbard, Fred; Leung, Kevin; Navrotsky, Alexandra (University of California, Davis, CA); Iyer, Ratnasabapathy G. (University of California, Davis, CA); Axness, Marlene

    2006-11-01

    In an effort to produce hydrogen without the unwanted greenhouse gas byproducts, high-temperature thermochemical cycles driven by heat from solar energy or next-generation nuclear power plants are being explored. The process being developed is the thermochemical production of Hydrogen. The Sulfur-Iodide (SI) cycle was deemed to be one of the most promising cycles to explore. The first step of the SI cycle involves the decomposition of H{sub 2}SO{sub 4} into O{sub 2}, SO{sub 2}, and H{sub 2}O at temperatures around 850 C. In-situ removal of O{sub 2} from this reaction pushes the equilibrium towards dissociation, thus increasing the overall efficiency of the decomposition reaction. A membrane is required for this oxygen separation step that is capable of withstanding the high temperatures and corrosive conditions inherent in this process. Mixed ionic-electronic perovskites and perovskite-related structures are potential materials for oxygen separation membranes owing to their robustness, ability to form dense ceramics, capacity to stabilize oxygen nonstoichiometry, and mixed ionic/electronic conductivity. Two oxide families with promising results were studied: the double-substituted perovskite A{sub x}Sr{sub 1-x}Co{sub 1-y}B{sub y}O{sub 3-{delta}} (A=La, Y; B=Cr-Ni), in particular the family La{sub x}Sr{sub 1-x}Co{sub 1-y}Mn{sub y}O{sub 3-{delta}} (LSCM), and doped La{sub 2}Ni{sub 1-x}M{sub x}O{sub 4} (M = Cu, Zn). Materials and membranes were synthesized by solid state methods and characterized by X-ray and neutron diffraction, SEM, thermal analyses, calorimetry and conductivity. Furthermore, we were able to leverage our program with a DOE/NE sponsored H{sub 2}SO{sub 4} decomposition reactor study (at Sandia), in which our membranes were tested in the actual H{sub 2}SO{sub 4} decomposition step.

  7. Performance of supercritical Brayton cycle using CO2-based binary mixture at varying critical points for SFR applications

    International Nuclear Information System (INIS)

    Jeong, Woo Seok; Jeong, Yong Hoon

    2013-01-01

    Highlights: • Supercritical CO 2 -based gas mixture Brayton cycles were investigated for a SFR. • The critical point of CO 2 is the lowest cycle operating limit of the S-CO 2 cycles. • Mixing additives with CO 2 changes the CO 2 critical point. • CO 2 –Xe and CO 2 –Kr cycles achieve higher cycle efficiencies than the S-CO 2 cycles. • CO 2 –H 2 S and CO 2 –cyclohexane cycles perform better at higher heat sink temperatures. -- Abstract: The supercritical carbon dioxide Brayton cycle (S-CO 2 cycle) has attracted much attention as an alternative to the Rankine cycle for sodium-cooled fast reactors (SFRs). The higher cycle efficiency of the S-CO 2 cycle results from the considerably decreased compressor work because the compressor behaves as a pump in the proximity of the CO 2 vapor–liquid critical point. In order to fully utilize this feature, the main compressor inlet condition should be controlled to be close to the critical point of CO 2 . This indicates that the critical point of CO 2 is a constraint on the minimum cycle condition for S-CO 2 cycles. Modifying the CO 2 critical point by mixing additive gases could be considered as a method of enhancing the performance and broadening the applicability of the S-CO 2 cycle. Due to the drastic fluctuations of the thermo-physical properties of fluids near the critical point, an in-house cycle analysis code using the NIST REFPROP database was implemented. Several gases were selected as potential additives considering their thermal stability and chemical interaction with sodium in the temperature range of interest and the availability of the mixture property database: xenon, krypton, hydrogen sulfide, and cyclohexane. The performances of the optimized CO 2 -containing binary mixture cycles with simple recuperated and recompression layouts were compared with the reference S-CO 2 , CO 2 –Ar, CO 2 –N 2 , and CO 2 –O 2 cycles. For the decreased critical temperatures, the CO 2 –Xe and CO 2

  8. Experimental study of the mechanisms of CO{sub 2} capture by calcium cycle under circulating fluidized bed conditions; Etude experimentale des mecanismes de capture du CO{sub 2} par cycle calcium en lit fluidise circulant

    Energy Technology Data Exchange (ETDEWEB)

    Hoteit, A

    2006-06-15

    The work undertaken in this Thesis in partnership with department R and D of ALSTOM Power Boilers, CEMEX and the ADEME, relates to the experimental study of various phenomena associated to CO{sub 2} capture under circulating fluidized bed conditions. The size of particles, temperature and the CO{sub 2} concentration have an influence on the limestone calcination reaction. The reaction of carbonation of lime is not total. During successive cycles of calcination/carbonation, the rate of carbonation obtained with hydrated lime is increasingly higher than that obtained with the lime. Under continuously reducing conditions, the decomposition of sulphates present in the bed ashes is not total. This decomposition is total under reduction/oxidation cycles. A modeling of calcination allowed to determine the intrinsic kinetic constants of calcination and carbonation. (author)

  9. Optimized, Competitive Supercritical-CO2 Cycle GFR for Gen IV Service

    International Nuclear Information System (INIS)

    M.J. Driscoll; P. Hejzlar; G. Apostolakis

    2008-01-01

    An overall plant design was developed for a gas-cooled fast reactor employing a direct supercritical Brayton power conversion system. The most important findings were that (1) the concept could be capital-cost competitive, but startup fuel cycle costs are penalized by the low core power density, specified in large part to satisfy the goal of significant post-accident passive natural convection cooling; (2) active decay heat removal is preferable as the first line of defense, with passive performance in a backup role; (3) an innovative tube-in-duct fuel assembly, vented to the primary coolant, appears to be practicable; and (4) use of the S-Co2 GFR to support hydrogen production is a synergistic application, since sufficient energy can be recuperated from the product H2 and 02 to allow the electrolysis cell to run 250 C hotter than the reactor coolant, and the water boilers can be used for reactor decay heat removal. Increasing core power density is identified as the top priority for future work on GFRs of this type

  10. Second law analysis of the transcritical CO2 refrigeration cycle

    International Nuclear Information System (INIS)

    Fartaj, Amir; Ting, David S.-K.; Yang, Wendy W.

    2004-01-01

    Because of the global warming impact of HFCs, the use of natural refrigerants has received worldwide attention. Efficient use of refrigerants is of pressing concern to the present automotive and HVAC industries. The natural refrigerant, carbon dioxide (CO 2 ), exhibits promise for use in automotive air conditioning systems, in particular the transcritical CO 2 refrigeration cycle. The objective of this work is to identify the main factors that affect CO 2 system performance. A second law of thermodynamic analysis on the entire CO 2 refrigeration cycle is conducted so that the effectiveness of the components of the system can be deduced and ranked, allowing future efforts to focus on improving the components that have the highest potential for advancement. The analysis reveals that the compressor and the gas cooler exhibit the largest non-idealities within the system, and hence, efforts should be focused on improving these components

  11. Entropy, exergy, and cost analyses of solar driven cogeneration systems using supercritical CO_2 Brayton cycles and MEE-TVC desalination system

    International Nuclear Information System (INIS)

    Kouta, Amine; Al-Sulaiman, Fahad; Atif, Maimoon; Marshad, Saud Bin

    2016-01-01

    Highlights: • The entropy, exergy, and cost analyses for two solar cogeneration configurations are conducted. • The recompression cogeneration cycle achieves lower LCOE as compared to the regeneration cogeneration cycle. • The solar tower is the largest contributor to entropy generation in both configurations reaching almost 80%. • The specific entropy generation in the MEE-TVC decreases with decreasing the fraction. - Abstract: In this study, performance and cost analyses are conducted for a solar power tower integrated with supercritical CO_2 (sCO_2) Brayton cycles for power production and a multiple effect evaporation with a thermal vapor compression (MEE-TVC) desalination system for water production. The study is performed for two configurations based on two different supercritical cycles: the regeneration and recompression sCO_2 Brayton cycles. A two-tank molten salt storage is utilized to ensure a uniform operation throughout the day. From the entropy analysis, it was shown that the solar tower is the largest contributor to entropy generation in both configurations, reaching almost 80% from the total entropy generation, followed by the MEE-TVC desalination system, and the sCO_2 power cycle. The entropy generation in the two-tank thermal storage is negligible, around 0.3% from the total generation. In the MEE-TVC system the highest contributing component is the steam jet ejector, which is varying between 50% and 60% for different number of effects. The specific entropy generation in the MEE-TVC decreases as the fraction of the input heat to the desalination system decreases; while the specific entropy generation of the sCO_2 cycle remains constant. The cost analysis performed for different regions in Saudi Arabia and the findings reveal that the regions characterized by the highest average solar irradiation throughout the year have the lowest LCOE and LCOW values. The region achieving the lowest cost is Yanbu, followed by Khabt Al-Ghusn in the second

  12. Efficiencies of subcritical and transcritical CO2 inverse cycles with and without an internal heat exchanger

    International Nuclear Information System (INIS)

    Zhang, F.Z.; Jiang, P.X.; Lin, Y.S.; Zhang, Y.W.

    2011-01-01

    An internal heat exchanger (IHX) is often used to improve the coefficient of performance (COP) of CO 2 inverse cycles. This paper presents a detailed analysis of the IHX's effect in CO 2 inverse cycles and finds suitable operating conditions for the IHX from a thermodynamic performance point of view. The results indicate that the COP is slightly reduced by an IHX in a CO 2 subcritical inverse cycle, so an IHX is not justified. However, for transcritical CO 2 inverse cycles, the compressor discharge pressures and CO 2 gas cooler outlet temperatures both have significant impacts on system performance. The analysis results for transcritical CO 2 inverse cycles show that a transition discharge pressure and a transition CO 2 gas cooler outlet temperature are objective existence above which the IHX improves the cycle performance. - Research highlights: → Find suitable operating conditions for the IHX. → Above transition CO2 gas cooler outlet temperature IHX improves cycle performance. → The IHX is not very useful for optimized space heating and refrigerating cycles.

  13. Preliminary Studies of Na{sub 2}CO{sub 3} Cleaning from Na-CO{sub 2} Interaction in S-CO{sub 2} Power Cycle coupled to SFR System

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hwa-Young; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Wi, Myung-Hwan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Ahn, Hong Joo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    Once the flow channel is plugged, to replace the plugged channel, the whole system operation should be stopped or a bypass system is necessary.. Therefore, finding a material which can clean up the solid reaction products from Na-CO{sub 2} interaction and the contaminated system with little or no impact on economics can be a valuable research. Hence, a screening process of selecting candidate materials was adopted to find a potential substance which can act as a cleaning agent in the previous study. It is essential to ensure the system economics as well as safety of SFR coupled with S-CO{sub 2} Brayton power conversion system. For this reason, the experiment was conducted to see the possibility of reaction between each selected potential substance and Na{sub 2}CO{sub 3}, which is the major product of the reaction. Na{sub 2}CO{sub 3} does not melt before 856 .deg. C This study was performed with the collaboration of Korea Atomic Energy Research Institute (KAERI) and Korea Advanced Institute of Science and Technology (KAIST). Liquid sodium and CO{sub 2} gas would react then produce the solid reaction products when the pressure boundary of sodium-CO{sub 2} heat exchanger fails. The solid reaction products are possible to plug the narrow flow channel of PCHE and this concerns the system economics. Thus, it is necessary to search a method for cleaning the solid reaction products which is mainly Na{sub 2}CO{sub 3}. From the preliminary study, some sodium-based compounds were selected and the mixtures of several sodium-based compounds with Na{sub 2}CO{sub 3} were thermally analyzed by the TG/DTA studies. Unfortunately, the selected sodium-based compounds, NaBrO{sub 3}, NaClO{sub 3} and NaBF{sub 4}, decomposed before 600 .deg. C and did not react with Na{sub 2}CO{sub 3}. In the near future, further research will be performed to search other compounds for cleaning the solid reaction products.

  14. Effects of wind intermittency on reduction of CO2 emissions: The case of the Spanish power system

    International Nuclear Information System (INIS)

    Gutiérrez-Martín, F.; Da Silva-Álvarez, R.A.; Montoro-Pintado, P.

    2013-01-01

    Renewable energy sources are believed to reduce drastically greenhouse gas emissions that would otherwise be generated from fossil fuels used to generate electricity. This implies that a unit of renewable energy will replace a unit of fossil-fuel, with its CO 2 emissions, on an equivalent basis – with no other effects on the grid. But, the fuel economy and emissions in the existing power systems are not proportional with the electricity production of intermittent sources due to cycling of the fossil-fuel plants that make up the balance of the grid (i.e. changing the power output makes thermal units to operate less efficiently). This study focuses in the interactions between wind generation and thermal plants cycling, by establishing the levels of extra fuel use caused by decreased efficiencies of fossil back-up for wind electricity in Spain. We analyze the production of all thermal plants in 2011, studying scenarios where wind penetration causes major deviations in programming and we define a procedure for quantifying CO 2 reductions using emission factors and efficiency curves from existing installations; the objective is to discuss the real contribution of renewable energy to the environmental targets: the results show that CO 2 reductions are still relevant at high wind penetration, whilst we also suggest alternatives to improve reliability of the power system. - Highlights: ► Comprehensive analysis of interactions of wind and fuel utilities in the power system. ► Fuel economy is not proportional with wind generation due to cycling of fossil plants. ► The results show that CO 2 reductions are still relevant even at high wind penetration. ► Alternatives to improve reliability of future power systems are also pointed out

  15. Improvement of system code importing evaluation of Life Cycle Analysis of tokamak fusion power reactors

    International Nuclear Information System (INIS)

    Kobori, Hikaru; Kasada, Ryuta; Hiwatari, Ryoji; Konishi, Satoshi

    2016-01-01

    Highlights: • We incorporated the Life Cycle Analysis (LCA) of tokamak type DEMO reactor and following commercial reactors as an extension of a system code. • We calculated CO_2 emissions from reactor construction, operation and decommissioning that is considered as a major environmental cost. • We found that the objective of conceptual design of the tokamak fusion power reactor is moved by changing evaluation index. • The tokamak fusion reactor can reduce CO_2 emissions in the life cycle effectively by reduction of the amount involved in the replacement of internal components. • The tokamak fusion reactor achieves under 0.174$/kWh electricity cost, the tokamak fusion reactor is contestable with 1500 degrees-class LNG-fired combined cycle power plant. - Abstract: This study incorporate the Life Cycle Analysis (LCA) of tokamak type DEMO reactor and following commercial reactors as an extension of a system code to calculate CO_2 emissions from reactor construction, operation and decommissioning that is considered as a major environmental cost. Competitiveness of tokamak fusion power reactors is expected to be evaluated by the cost and environmental impact represented by the CO_2 emissions, compared with present and future power generating systems such as fossil, nuclear and renewables. Result indicated that (1) The objective of conceptual design of the tokamak fusion power reactor is moved by changing evaluation index. (2) The tokamak fusion reactor can reduce CO_2 emissions in the life cycle effectively by reduction of the amount involved in the replacement of internal components. (3) The tokamak fusion reactor achieves under 0.174$/kWh electricity cost, the tokamak fusion reactor is contestable with 1500 degrees-class LNG-fired combined cycle power plant.

  16. Improvement of system code importing evaluation of Life Cycle Analysis of tokamak fusion power reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kobori, Hikaru [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Kasada, Ryuta, E-mail: r-kasada@iae.kyoto-u.ac.jp [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Hiwatari, Ryoji [Central Research Institute of Electric Power Industry, Tokyo (Japan); Konishi, Satoshi [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)

    2016-11-01

    Highlights: • We incorporated the Life Cycle Analysis (LCA) of tokamak type DEMO reactor and following commercial reactors as an extension of a system code. • We calculated CO{sub 2} emissions from reactor construction, operation and decommissioning that is considered as a major environmental cost. • We found that the objective of conceptual design of the tokamak fusion power reactor is moved by changing evaluation index. • The tokamak fusion reactor can reduce CO{sub 2} emissions in the life cycle effectively by reduction of the amount involved in the replacement of internal components. • The tokamak fusion reactor achieves under 0.174$/kWh electricity cost, the tokamak fusion reactor is contestable with 1500 degrees-class LNG-fired combined cycle power plant. - Abstract: This study incorporate the Life Cycle Analysis (LCA) of tokamak type DEMO reactor and following commercial reactors as an extension of a system code to calculate CO{sub 2} emissions from reactor construction, operation and decommissioning that is considered as a major environmental cost. Competitiveness of tokamak fusion power reactors is expected to be evaluated by the cost and environmental impact represented by the CO{sub 2} emissions, compared with present and future power generating systems such as fossil, nuclear and renewables. Result indicated that (1) The objective of conceptual design of the tokamak fusion power reactor is moved by changing evaluation index. (2) The tokamak fusion reactor can reduce CO{sub 2} emissions in the life cycle effectively by reduction of the amount involved in the replacement of internal components. (3) The tokamak fusion reactor achieves under 0.174$/kWh electricity cost, the tokamak fusion reactor is contestable with 1500 degrees-class LNG-fired combined cycle power plant.

  17. Metallic CoS2 nanowire electrodes for high cycling performance supercapacitors

    Science.gov (United States)

    Ren, Ren; Faber, Matthew S.; Dziedzic, Rafal; Wen, Zhenhai; Jin, Song; Mao, Shun; Chen, Junhong

    2015-12-01

    We report metallic cobalt pyrite (CoS2) nanowires (NWs) prepared directly on current collecting electrodes, e.g., carbon cloth or graphite disc, for high-performance supercapacitors. These CoS2 NWs have a variety of advantages for supercapacitor applications. Because the metallic CoS2 NWs are synthesized directly on the current collector, the good electrical connection enables efficient charge transfer between the active CoS2 materials and the current collector. In addition, the open spaces between the sea urchin structure NWs lead to a large accessible surface area and afford rapid mass transport. Moreover, the robust CoS2 NW structure results in high stability of the active materials during long-term operation. Electrochemical characterization reveals that the CoS2 NWs enable large specific capacitance (828.2 F g-1 at a scan rate of 0.01 V s-1) and excellent long term cycling stability (0-2.5% capacity loss after 4250 cycles at 5 A g-1) for pseudocapacitors. This example of metallic CoS2 NWs for supercapacitor applications expands the opportunities for transition metal sulfide-based nanostructures in emerging energy storage applications.

  18. Predicting the ultimate potential of natural gas SOFC power cycles with CO2 capture : Part B: Applications

    NARCIS (Netherlands)

    Campanari, Stefano; Mastropasqua, Luca; Gazzani, Matteo; Chiesa, Paolo; Romano, Matteo C.

    2016-01-01

    An important advantage of solid oxide fuel cells (SOFC) as future systems for large scale power generation is the possibility of being efficiently integrated with processes for CO2 capture. Focusing on natural gas power generation, Part A of this work assessed the performances of advanced

  19. Dependency of climate change and carbon cycle on CO2 emission pathways

    International Nuclear Information System (INIS)

    Nohara, Daisuke; Yoshida, Yoshikatsu; Misumi, Kazuhiro; Ohba, Masamichi

    2013-01-01

    Previous research has indicated that the response of globally average temperature is approximately proportional to cumulative CO 2 emissions, yet evidence of the robustness of this relationship over a range of CO 2 emission pathways is lacking. To address this, we evaluate the dependency of climate and carbon cycle change on CO 2 emission pathways using a fully coupled climate–carbon cycle model. We design five idealized pathways (including an overshoot scenario for cumulative emissions), each of which levels off to final cumulative emissions of 2000 GtC. The cumulative emissions of the overshoot scenario reach 4000 GtC temporarily, subsequently reducing to 2000 GtC as a result of continuous negative emissions. Although we find that responses of climatic variables and the carbon cycle are largely independent of emission pathways, a much weakened Atlantic meridional overturning circulation (AMOC) is projected in the overshoot scenario despite cessation of emissions. This weakened AMOC is enhanced by rapid warming in the Arctic region due to considerable temporary elevation of atmospheric CO 2 concentration and induces the decline of surface air temperature and decrease of precipitation over the northern Atlantic and Europe region. Moreover, the weakened AMOC reduces CO 2 uptake by the Atlantic and Arctic oceans. However, the weakened AMOC contributes little to the global carbon cycle. In conclusion, although climate variations have been found to be dependent on emission pathways, the global carbon cycle is relatively independent of these emission pathways, at least superficially. (letter)

  20. Prediction and attendance of Angra 2 nuclear power plant cycle extension

    International Nuclear Information System (INIS)

    Dias, Amory; Ferreira Junior, Decio Brandes M.; Morgado, Mario Monteiro; Santos, Barbara Oliveira dos; Oliveira, Monica Georgia Nunes

    2007-01-01

    The Report Project Nuclear and Thermohydraulic (RPNT) of the Nuclear Power Plant Angra 2 previews extension of the cycle, using a feedback of core reactor reactivity, through the reduction of the moderator average temperature and power. In this phase, the reactor power remains almost invariable. Furthermore, the extension of cycle can be stretch after the limit of the temperature reduction has been reached, through of reactor power fall until the determined date for the end cycle and the start outage for the next cycle. The proposal of this work is to show the Power Plant results during the phase of moderator temperature reduction and to compare with the predict values obtained from reactivity balance calculation methodology used for the Reactor Physics. In general, the results of this work can collaborate for the extension behavior evaluation of the cycles of the Nuclear Power Plant 2, being used the procedure of cooling reduction average temperature, as well as, it will also collaborate for methodology qualification applied for the Reactor Physics during the reactivity balance calculation. (author)

  1. Thermodynamic analysis of a new dual evaporator CO2 transcritical refrigeration cycle

    Science.gov (United States)

    Abdellaoui, Ezzaalouni Yathreb; Kairouani, Lakdar Kairouani

    2017-03-01

    In this work, a new dual-evaporator CO2 transcritical refrigeration cycle with two ejectors is proposed. In this new system, we proposed to recover the lost energy of condensation coming off the gas cooler and operate the refrigeration cycle ejector free and enhance the system performance and obtain dual-temperature refrigeration simultaneously. The effects of some key parameters on the thermodynamic performance of the modified cycle are theoretically investigated based on energetic and exergetic analysis. The simulation results for the modified cycle indicate more effective system performance improvement than the single ejector in the CO2 vapor compression cycle using ejector as an expander ranging up to 46%. The exergetic analysis for this system is made. The performance characteristics of the proposed cycle show its promise in dual-evaporator refrigeration system.

  2. Thermodynamic analysis of a new dual evaporator CO2 transcritical refrigeration cycle

    Directory of Open Access Journals (Sweden)

    Abdellaoui Ezzaalouni Yathreb

    2017-03-01

    Full Text Available In this work, a new dual-evaporator CO2 transcritical refrigeration cycle with two ejectors is proposed. In this new system, we proposed to recover the lost energy of condensation coming off the gas cooler and operate the refrigeration cycle ejector free and enhance the system performance and obtain dual-temperature refrigeration simultaneously. The effects of some key parameters on the thermodynamic performance of the modified cycle are theoretically investigated based on energetic and exergetic analysis. The simulation results for the modified cycle indicate more effective system performance improvement than the single ejector in the CO2 vapor compression cycle using ejector as an expander ranging up to 46%. The exergetic analysis for this system is made. The performance characteristics of the proposed cycle show its promise in dual-evaporator refrigeration system.

  3. A technical evaluation, performance analysis and risk assessment of multiple novel oxy-turbine power cycles with complete CO2 capture

    OpenAIRE

    Barba, F. C.; Sanchez, Guillermo Martinez-Denegri; Segui, Blanca Soler; Darabkhani, Hamidreza Gohari; Anthony, Edward J.

    2016-01-01

    In recent years there has been growing concern about greenhouse gas emissions (particularly CO2 emissions) and global warming. Oxyfuel combustion is one of the key technologies for tackling CO2 emissions in the power industry and reducing their contribution to global warming. The technology involves burning fuel with high-purity oxygen to generate mainly CO2 and steam, enabling easy CO2 separation from the flue gases by steam condensation. In fact, 100% CO2 capture and near-zero NOx emissions...

  4. Integrated underground gas storage of CO2 and CH4 to decarbonize the "power-to-gas-to-gas-to-power" technology

    Science.gov (United States)

    Kühn, Michael; Streibel, Martin; Nakaten, Natalie; Kempka, Thomas

    2014-05-01

    Massive roll-out of renewable energy production units (wind turbines and solar panels) leads to date to excess energy which cannot be consumed at the time of production. So far, long-term storage is proposed via the so called 'power-to-gas' technology. Energy is transferred to methane gas and subsequently combusted for power production - 'power-to-gas-to-power' (PGP) - when needed. PGP profits from the existing infrastructure of the gas market and could be deployed immediately. However, major shortcoming is the production of carbon dioxide (CO2) from renewables and its emission into the atmosphere. We present an innovative idea which is a decarbonised extension of the PGP technology. The concept is based on a closed carbon cycle: (1) Hydrogen (H2) is generated from renewable energy by electrolysis and (2) transformed into methane (CH4) with CO2 taken from an underground geological storage. (3) CH4 produced is stored in a second storage underground until needed and (4) combusted in a combined-cycled power plant on site. (5) CO2 is separated during energy production and re-injected into the storage formation. We studied a show case for the cities Potsdam and Brandenburg/Havel in the Federal State of Brandenburg in Germany to determine the energy demand of the entire process chain and the costs of electricity (COE) using an integrated techno-economic modelling approach (Nakaten et al. 2014). Taking all of the individual process steps into account, the calculation shows an overall efficiency of 27.7 % (Streibel et al. 2013) with total COE of 20.43 euro-cents/kWh (Kühn et al. 2013). Although the level of efficiency is lower than for pump and compressed air storage, the resulting costs are similar in magnitude, and thus competitive on the energy storage market. The great advantage of the concept proposed here is that, in contrast to previous PGP approaches, this process is climate-neutral due to CO2 utilisation. For that purpose, process CO2 is temporally stored in an

  5. SO{sub 2} Retention by CaO-Based Sorbent Spent in CO{sub 2} Looping Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Manovic, V.; Anthony, E.J.; Loncarevic, D.

    2009-07-15

    CaO-based looping cycles are promising processes for CO{sub 2} Capture from both syngas and flue gas. The technology is based on cyclical carbonation of CaO and regeneration of CaCO{sub 3} in a dual fluidized-bed reactor to produce a pure CO{sub 2} stream suitable for sequestration. Use of spent sorbent from CO{sub 2} looping cycles for SO{sub 2} capture is investigated. Three limestones were investigated: Kelly Rock (Canada), La Blanca (Spain), and Katowice (Poland, Upper Silesia). Carbonation/calcination cycles were performed in a tube furnace with both the original limestones and samples thermally pretreated for different times (i.e., sintered). The spent sorbent samples were sulfated in a thermogravimetric analyzer (TGA). The changes in the resulting sorbent pore structure were then investigated using mercury porosimetry. It has been shown that the sulfation rates of both thermally pretreated and spent sorbent samples are lower in comparison with those of the original samples. However, final conversions of both spent and pretreated sorbents after longer sulfation time were comparable or higher than those observed for the original sorbents under comparable conditions. Maximum sulfation levels strongly depend on sorbent porosity and pore surface area. The results showed that spent sorbent samples from CO{sub 2} looping cycles can be used as sorbents for SO{sub 2} retention in cases where significant porosity loss does not occur during CO{sub 2} reaction cycles. In the case of spent Kelly Rock and Katowice samples, sorbent particles are practically uniformly sulfated, achieving final conversions that are determined by the total pore volume available for the bulky CaSO{sub 4} product.

  6. Committed CO2 Emissions of China's Coal-fired Power Plants

    Science.gov (United States)

    Suqin, J.

    2016-12-01

    The extent of global warming is determined by the cumulative effects of CO2 in the atmosphere. Coal-fired power plants, the largest anthropogenic source of CO2 emissions, produce large amount of CO2 emissions during their lifetimes of operation (committed emissions), which thus influence the future carbon emission space under specific targets on mitigating climate change (e.g., the 2 degree warming limit relative to pre-industrial levels). Comprehensive understanding of committed CO2 emissions for coal-fired power generators is urgently needed in mitigating global climate change, especially in China, the largest global CO2emitter. We calculated China's committed CO2 emissions from coal-fired power generators installed during 1993-2013 and evaluated their impact on future emission spaces at the provincial level, by using local specific data on the newly installed capacities. The committed CO2 emissions are calculated as the product of the annual coal consumption from newly installed capacities, emission factors (CO2emissions per unit crude coal consumption) and expected lifetimes. The sensitivities about generators lifetimes and the drivers on provincial committed emissions are also analyzed. Our results show that these relatively recently installed coal-fired power generators will lead to 106 Gt of CO2 emissions over the course of their lifetimes, which is more than three times the global CO2 emissions from fossil fuels in 2010. More than 80% (85 Gt) of their total committed CO2 will be emitted after 2013, which are referred to as the remaining emissions. Due to the uncertainties of generators lifetime, these remaining emissions would increase by 45 Gt if the lifetimes of China's coal-fired power generators were prolonged by 15 years. Furthermore, the remaining emissions are very different among various provinces owing to local developments and policy disparities. Provinces with large amounts of secondary industry and abundant coal reserves have higher committed

  7. Experimental study of the mechanisms of CO2 capture by calcium cycle under circulating fluidized bed conditions

    International Nuclear Information System (INIS)

    Hoteit, A.

    2006-06-01

    The work undertaken in this Thesis in partnership with department R and D of ALSTOM Power Boilers, CEMEX and the ADEME, relates to the experimental study of various phenomena associated to CO 2 capture under circulating fluidized bed conditions. The size of particles, temperature and the CO 2 concentration have an influence on the limestone calcination reaction. The reaction of carbonation of lime is not total. During successive cycles of calcination/carbonation, the rate of carbonation obtained with hydrated lime is increasingly higher than that obtained with the lime. Under continuously reducing conditions, the decomposition of sulphates present in the bed ashes is not total. This decomposition is total under reduction/oxidation cycles. A modeling of calcination allowed to determine the intrinsic kinetic constants of calcination and carbonation. (author)

  8. Effect of process parameters on power requirements of vacuum swing adsorption technology for CO2 capture from flue gas

    International Nuclear Information System (INIS)

    Zhang, Jun; Webley, Paul A.; Xiao, Penny

    2008-01-01

    This study focuses on the effects of process and operating parameters - feed gas temperature, evacuation pressure and feed concentration - on the performance of carbon dioxide vacuum swing adsorption (CO 2 VSA) processes for CO 2 capture from gas, especially as it affects power consumption. To obtain reliable data on the VSA process, experimental work was conducted on a purposely built three bed CO 2 VSA pilot plant using commercial 13X zeolite. Both 6 step and 9 step cycles were used to determine the influences of temperature, evacuation pressure and feed concentration on process performance (recovery, purity, power and corresponding capture cost). A simple economic model for CO 2 capture was developed and employed herein. Through experiments and analysis, it is found that the feed gas temperature, evacuation pressure and feed concentration have significant effects on power consumption and CO 2 capture cost. Our data demonstrate that the CO 2 VSA process has good recovery (>70%), purity (>90%) and low power cost (4-10 kW/TPDc) when operating with 40 C feed gas provided relatively deep vacuum is used. Enhanced performance is obtained when higher feed gas concentration is fed to the plant, as expected. Our data indicates large potential for application of CO 2 VSA to CO 2 capture from flue gas. (author)

  9. Different sorbents in calcium looping cycle for CO{sub 2} capture

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Cong; Zheng, Ying; Ding, Ning [Huazhong Univ. of Science and Technology, Wuhan (China). State Key Lab. of Coal Combustion

    2013-07-01

    Cyclic CO{sub 2} capture using commercial pure micro CaCO{sub 3} and nano CaCO{sub 3} is investigated in this paper which focuses on the different characteristics two different sorbents during high temperature reactions. The results indicate that the nano CaCO{sub 3} sorbent has higher carbonation conversions and carbonation rates than the micro CaCO{sub 3} sorbent in the cyclic reactions. Furthermore, nano sorbent can retain its fast carbonation rates at the beginning dozens of seconds during each cycle. In contrast, the carbonation rates of micro sorbent diminish with the increase of cycle number. But, unfortunately, CaO derived from nano CaCO3 sorbent sinter much easily. Its grains, which are composed of numerous spherical nanocrystallites, experience dramatic morphological changes during high temperature reactions.

  10. Understanding future emissions from low-carbon power systems by integration of life-cycle assessment and integrated energy modelling

    Science.gov (United States)

    Pehl, Michaja; Arvesen, Anders; Humpenöder, Florian; Popp, Alexander; Hertwich, Edgar G.; Luderer, Gunnar

    2017-12-01

    Both fossil-fuel and non-fossil-fuel power technologies induce life-cycle greenhouse gas emissions, mainly due to their embodied energy requirements for construction and operation, and upstream CH4 emissions. Here, we integrate prospective life-cycle assessment with global integrated energy-economy-land-use-climate modelling to explore life-cycle emissions of future low-carbon power supply systems and implications for technology choice. Future per-unit life-cycle emissions differ substantially across technologies. For a climate protection scenario, we project life-cycle emissions from fossil fuel carbon capture and sequestration plants of 78-110 gCO2eq kWh-1, compared with 3.5-12 gCO2eq kWh-1 for nuclear, wind and solar power for 2050. Life-cycle emissions from hydropower and bioenergy are substantial (˜100 gCO2eq kWh-1), but highly uncertain. We find that cumulative emissions attributable to upscaling low-carbon power other than hydropower are small compared with direct sectoral fossil fuel emissions and the total carbon budget. Fully considering life-cycle greenhouse gas emissions has only modest effects on the scale and structure of power production in cost-optimal mitigation scenarios.

  11. The future of integrated coal gasification combined cycle power plants

    International Nuclear Information System (INIS)

    Mueller, R.; Termuehlen, H.

    1991-01-01

    This paper examines the future of integrated coal gasification combined cycle (IGCC) power plants as affected by various technical, economical and environmental trends in power generation. The topics of the paper include a description of natural gas-fired combined cycle power plants, IGCC plants, coal gasifier concepts, integration of gasifiers into combined cycle power plants, efficiency, environmental impacts, co-products of IGCC power plants, economics of IGCC power plants, and a review of IGCC power plant projects

  12. Experimental Investigation of Gaseous Reaction Products from Na-CO{sub 2} Reaction in Na/CO{sub 2} Heat Exchanger leakage scenario

    Energy Technology Data Exchange (ETDEWEB)

    Go, A-Reum; Jung, Hwa-Young; Kim, Min Seok; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of); Min, Jaehong; Wi, Myung-Hwan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The SFRs have operated with the steam Rankine cycle as a power conversion system. However, the potential sodium-water reaction (SWR) whose chemical reactivity is vigorous and instantaneous has been one of the major issues concerning the safety and integrity of the SFRs. In order to avoid SWR, supercritical CO{sub 2}(S-CO{sub 2}) Brayton cycles have been investigated recently. Compared to conventional steam Rankine cycles, S-CO{sub 2} Brayton cycle features higher thermal efficiency and potential compactness of its required equipment. In spite of the superiority of S-CO{sub 2} Brayton cycle, there is a potential reactive process between sodium and CO{sub 2} if the pressure boundary fails in the sodium-CO{sub 2} heat exchanger. The leakage scenario which could lead to mechanical and thermal problems should be evaluated. Previous studies have reported the following major reaction formulas. Each reaction occurs competitively. In this paper, the experimental setup to observe the pressure variation and CO concentration in Na-CO{sub 2} heat exchanger during the CO{sub 2} leak is explained. Before the experiment is carried out, water-CO{sub 2} mock-up test will be performed. In order to evaluate the leakage scenario in Na-CO{sub 2} heat exchanger more accurately, this study will be important for guaranteeing the system of SFR coupled with S-CO{sub 2} cycle.

  13. Transient Model of a 10 MW Supercritical CO{sub 2} Brayton Cycle for Light Water Reactors by using MARS Code

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joo-Hyun; Park, Hyun Sun; Kim, Moo Hwan [POSTECH, Pohang (Korea, Republic of); Bae, Sung Won; Cha, Jae-Eun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    In this study, recuperation cycle was chosen as a reference loop design and the MARS code was chosen as the transient cycle analysis code. Cycle design condition is focus on operation point of the light-water reactor. Development of a transient model was performed for 10MW-electron SCO{sub 2} coupled with light water reactors. In order to perform transient analysis, cycle transient model was developed and steady-state run was performed and presented in the paper. In this study, the transient model of SCO{sub 2} recuperation Brayton cycle was developed and implemented in MARS to study the steady-state simulation. We performed nodalization of the transient model using MARS code and obtained steady-state results. This study is shown that the supercritical CO{sub 2} Brayton cycle can be used as a power conversion system for light water reactors. Future work will include transient analysis such as partial road operation, power swing, start-up, and shutdown. Cycle control strategy will be considered for various control method.

  14. CO2 emission costs and Gas/Coal competition for power production

    International Nuclear Information System (INIS)

    Santi, Federico

    2005-01-01

    This paper demonstrates how a CO 2 emission reduction programme can change the competition between the two power production technologies which will probably dominate the future of the Italian power industry: the coal fired USC steam power plant and the natural gas fired CCGT power plant. An economic value of the CO 2 emission is calculated, in order to make the short-run-marginal-cost (or the long-run-marginal-cost). equal for both technologies, under a CO 2 emission trading scheme and following a single-plant specific CO 2 emission homogenizing approach [it

  15. Evaluation Analysis of the CO2 Emission and Absorption Life Cycle for Precast Concrete in Korea

    Directory of Open Access Journals (Sweden)

    Taehyoung Kim

    2016-07-01

    Full Text Available To comply with recent international trends and initiatives, and in order to help achieve sustainable development, Korea has established a greenhouse gas (GHG emission reduction target of 37% (851 million tons of the business as usual (BAU rate by 2030. Regarding environmentally-oriented standards such as the IGCC (International Green Construction Code, there are also rising demands for the assessment on CO2 emissions during the life cycle in accordance with ISO (International Standardization Organization’s Standard 14040. At present, precast concrete (PC engineering-related studies primarily cover structural and construction aspects, including improvement of structural performance in the joint, introduction of pre-stressed concrete and development of half PC. In the manufacture of PC, steam curing is mostly used for the early-strength development of concrete. In steam curing, a large amount of CO2 is produced, causing an environmental problem. Therefore, this study proposes a method to assess CO2 emissions (including absorption throughout the PC life cycle by using a life cycle assessment (LCA method. Using the proposed assessment method, CO2 emissions during the life cycle of a precast concrete girder (PCG were assessed. In addition, CO2 absorption was assessed against a PCG using conventional carbonation and CO2 absorption-related models. As a result, the CO2 emissions throughout the life cycle of the PCG were 1365.6 (kg-CO2/1 PCG. The CO2 emissions during the production of raw materials among the CO2 emissions throughout the life cycle of the PCG were 1390 (kg-CO2/1 PCG, accounting for a high portion to total CO2 emissions (nearly 90%. In contrast, the transportation and manufacture stages were 1% and 10%, respectively, having little effect on total CO2 emissions. Among the use of the PCG, CO2 absorption was mostly decided by the CO2 diffusion coefficient and the amount of CO2 absorption by cement paste. The CO2 absorption by carbonation

  16. Study of CO2 capture processes in power plants

    International Nuclear Information System (INIS)

    Amann, J.M.

    2007-12-01

    The aim of the present study is to assess and compare various processes aiming at recover CO 2 from power plants fed with natural gas (NGCC) and pulverized coal (PC). These processes are post-combustion CO 2 capture using chemical solvents, natural gas reforming for pre-combustion capture by methanol and oxy-fuel combustion with cryogenic recovery of CO 2 . These processes were evaluated using the process software Aspen PlusTM to give some clues for choosing the best option for each type of power plant. With regard to post-combustion, an aqueous solution based on a mixture of amines (N-methyldiethanolamine (MDEA) and triethylene tetramine (TETA)) was developed. Measurements of absorption were carried out between 298 and 333 K in a Lewis cell. CO 2 partial pressure at equilibrium, characteristic of the CO 2 solubility in the solvent, was determined up to 393 K. The solvent performances were compared with respect to more conventional solvents such as MDEA and monoethanolamine (MEA). For oxy-fuel combustion, a recovery process, based on a cryogenic separation of the components of the flue gas, was developed and applied to power plants. The study showed that O 2 purity acts on the CO 2 concentration in the flue gas and thus on the performances of the recovery process. The last option is natural gas reforming with CO 2 pre-combustion capture. Several configurations were assessed: air reforming and oxygen reforming, reforming pressure and dilution of the synthesis gas. The comparison of these various concepts suggests that, in the short and medium term, chemical absorption is the most interesting process for NGCC power plants. For CP power plants, oxy-combustion can be a very interesting option, as well as post-combustion capture by chemical solvents. (author)

  17. CO{sub 2} capture efficiency and energy requirement analysis of power plant using modified calcium-based sorbent looping cycle

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.J.; Zhao, C.S.; Chen, H.C.; Ren, Q.Q.; Duan, L.B. [Southeast University, Nanjing (China). School of Energy & Environment

    2011-03-15

    This paper examines the average carbonation conversion, CO{sub 2} capture efficiency and energy requirement for post-combustion CO{sub 2} capture system during the modified calcium-based sorbent looping cycle. The limestone modified with acetic acid solution, i.e. calcium acetate is taken as an example of the modified calcium-based sorbents. The modified limestone exhibits much higher average carbonation conversion than the natural sorbent under the same condition. The CO{sub 2} capture efficiency increases with the sorbent flow ratios. Compared with the natural limestone, much less makeup mass flow of the recycled and the fresh sorbent is needed for the system when using the modified limestone at the same CO{sub 2} capture efficiency. Achieving 0.95 of CO{sub 2} capture efficiency without sulfation, 272 kJ/mol CO{sub 2} is required in the calciner for the natural limestone, whereas only 223 kJ/mol CO{sub 2} for the modified sorbent. The modified limestone possesses greater advantages in CO{sub 2} capture efficiency and energy consumption than the natural sorbent. When the sulfation and carbonation of the sorbents take place simultaneously, more energy is required. It is significantly necessary to remove SO{sub 2} from the flue gas before it enters the carbonator in order to reduce energy consumption in the calciner.

  18. CFD aided approach to design printed circuit heat exchangers for supercritical CO2 Brayton cycle application

    International Nuclear Information System (INIS)

    Kim, Seong Gu; Lee, Youho; Ahn, Yoonhan; Lee, Jeong Ik

    2016-01-01

    Highlights: • CFD analyses were performed to find performance of PCHE for supercritical CO 2 power cycle. • CFD results were obtained beyond the limits of existing correlations. • Designs of different PCHEs with different correlations were compared. • A new CFD-aided correlation covering a wider Reynolds number range was proposed. - Abstract: While most conventional PCHE designs for working fluid of supercritical CO 2 require an extension of valid Reynolds number limits of experimentally obtained correlations, Computational Fluid Dynamics (CFD) code ANSYS CFX was used to explore validity of existing correlations beyond their tested Reynolds number ranges. For heat transfer coefficient correlations, an appropriate piece-wising with Ishizuka’s and Hesselgreaves’s correlation is found to enable an extension of Reynolds numbers. For friction factors, no single existing correlation is found to capture different temperature and angular dependencies for a wide Reynolds number range. Based on the comparison of CFD results with the experimentally obtained correlations, a new CFD-aided correlation covering an extended range of Reynolds number 2000–58,000 for Nusselt number and friction factor is proposed to facilitate PCHE designs for the supercritical CO 2 Brayton cycle application.

  19. Development of a Performance Analysis Code for the Off-design conditions of a S-CO2 Brayton Cycle Energy Conversion System

    International Nuclear Information System (INIS)

    Yoo, Yong-Hwan; Cha, Jae-Eun; Lee, Tae-Ho; Eoh, Jae-Hyuk; Kim, Seong-O

    2008-01-01

    For the development of a supercritical carbon dioxide (S-CO2) Brayton cycle energy conversion system coupled to KALIMER-600, a thermal balance has been established on 100% power operating conditions including all the reactor system models such as a primary heat transport system (PHTS), an intermediate heat transport system (IHTS), and an energy conversion system. The S-CO2 Brayton cycle energy conversion system consists of a sodium-CO2 heat exchanger (Hx), turbine, high temperature recuperate (HTR), low temperature recuperate (LTR), precooler, compressor no.1, and compressor no.2. Two compressors were employed to avoid a sharp change of the physical properties near their critical point with a corresponding pressure. The component locations and their operating conditions are illustrated. Energy balance of the power conversion system in KALIMER-600 was designed with the full power condition of each component. Therefore, to predict the off-design conditions and to evaluate each component, an off-design performance analysis code should be accomplished. An off-design performance analysis could be classified into overall system control logic and local system control logic. The former means that mass flow rate and power are controlled by valves, and the latter implies that a bypass or inventory control is an admitted system balance. The ultimate goal of this study is development of the overall system control logic

  20. CO2: EDF's competitiveness is due to nuclear power

    International Nuclear Information System (INIS)

    Anon.

    2003-01-01

    The CO 2 emissions of EDF group (EDF-France + EDF-energy (UK) + Hidrocantabrico (Spain) + EnBW (Germany)) soared by 53% in 2002 which is due to the purchase of british and spanish electricity sub-companies using fossil energies. Despite this sharp increase EDF remains one of the most competitive electricity companies in Europe concerning greenhouse gas emissions. EDF group is the first electricity company in Europe, it generates 22% of the electricity produced in E.U and contributes to CO 2 emissions with a rate of 101 Kg CO 2 /MWh which 3 times less than the average rate of 20 other European companies (358 Kg CO 2 /MWh). This result is due to the large part of nuclear power in the French energy mix. The best electricity companies as far as CO 2 emissions are concerned are Statkraft (Norway) with 0 Kg CO 2 /MWh (100% hydrology) and British-energy (U.K) with 75 Kg CO 2 /MWh (75% nuclear power). At the other end we have the DEI company (Greece) with 863 Kg CO 2 /MWh (100% lignite). (A.C.)

  1. Future ocean hypercapnia driven by anthropogenic amplification of the natural CO2 cycle

    Science.gov (United States)

    McNeil, Ben I.; Sasse, Tristan P.

    2016-01-01

    High carbon dioxide (CO2) concentrations in sea-water (ocean hypercapnia) can induce neurological, physiological and behavioural deficiencies in marine animals. Prediction of the onset and evolution of hypercapnia in the ocean requires a good understanding of annual variations in oceanic CO2 concentration, but there is a lack of relevant global observational data. Here we identify global ocean patterns of monthly variability in carbon concentration using observations that allow us to examine the evolution of surface-ocean CO2 levels over the entire annual cycle under increasing atmospheric CO2 concentrations. We predict that the present-day amplitude of the natural oscillations in oceanic CO2 concentration will be amplified by up to tenfold in some regions by 2100, if atmospheric CO2 concentrations continue to rise throughout this century (according to the RCP8.5 scenario of the Intergovernmental Panel on Climate Change). The findings from our data are broadly consistent with projections from Earth system climate models. Our predicted amplification of the annual CO2 cycle displays distinct global patterns that may expose major fisheries in the Southern, Pacific and North Atlantic oceans to hypercapnia many decades earlier than is expected from average atmospheric CO2 concentrations. We suggest that these ocean ‘CO2 hotspots’ evolve as a combination of the strong seasonal dynamics of CO2 concentration and the long-term effective storage of anthropogenic CO2 in the oceans that lowers the buffer capacity in these regions, causing a nonlinear amplification of CO2 concentration over the annual cycle. The onset of ocean hypercapnia (when the partial pressure of CO2 in sea-water exceeds 1,000 micro-atmospheres) is forecast for atmospheric CO2 concentrations that exceed 650 parts per million, with hypercapnia expected in up to half the surface ocean by 2100, assuming a high-emissions scenario (RCP8.5). Such extensive ocean hypercapnia has detrimental implications for

  2. A Preliminary Assessment of the Initial Compression Power Requirement in CO2 Pipeline “Carbon Capture and Storage (CCS Technologies”

    Directory of Open Access Journals (Sweden)

    Abdussalam El-Suleiman

    2016-05-01

    Full Text Available CO2 captured from fossil-fueled power generation plants is said to be economically transported via pipelines over long distances. The CO2 must be compressed to pipeline specifications using compressors and pumps that are driven by gas turbine (GT or other prime movers. This paper presents the evaluation of actual work transfer or required prime power by modeling the governing equations of compression using the Peng–Robinson equation of state (PR-EOS. A computer code was developed to carry out the modeling and subsequent simulation of the compression power requirement. The simulation of prime mover power was carried out for different technology (head per stage of the compressor ranging from 10-staged compression to double stage compression. The results show that the current technology of the centrifugal compressor could require as much as 23MW of prime mover power to compress 1.5 million tonnes per year of CO2—a projected equivalent CO2 released from a 530MW combined cycle gas turbine (CCGT power generation plant.

  3. The seasonal cycle of pCO2 and CO2 fluxes in the Southern Ocean: diagnosing anomalies in CMIP5 Earth system models

    Science.gov (United States)

    Precious Mongwe, N.; Vichi, Marcello; Monteiro, Pedro M. S.

    2018-05-01

    The Southern Ocean forms an important component of the Earth system as a major sink of CO2 and heat. Recent studies based on the Coupled Model Intercomparison Project version 5 (CMIP5) Earth system models (ESMs) show that CMIP5 models disagree on the phasing of the seasonal cycle of the CO2 flux (FCO2) and compare poorly with available observation products for the Southern Ocean. Because the seasonal cycle is the dominant mode of CO2 variability in the Southern Ocean, its simulation is a rigorous test for models and their long-term projections. Here we examine the competing roles of temperature and dissolved inorganic carbon (DIC) as drivers of the seasonal cycle of pCO2 in the Southern Ocean to explain the mechanistic basis for the seasonal biases in CMIP5 models. We find that despite significant differences in the spatial characteristics of the mean annual fluxes, the intra-model homogeneity in the seasonal cycle of FCO2 is greater than observational products. FCO2 biases in CMIP5 models can be grouped into two main categories, i.e., group-SST and group-DIC. Group-SST models show an exaggeration of the seasonal rates of change of sea surface temperature (SST) in autumn and spring during the cooling and warming peaks. These higher-than-observed rates of change of SST tip the control of the seasonal cycle of pCO2 and FCO2 towards SST and result in a divergence between the observed and modeled seasonal cycles, particularly in the Sub-Antarctic Zone. While almost all analyzed models (9 out of 10) show these SST-driven biases, 3 out of 10 (namely NorESM1-ME, HadGEM-ES and MPI-ESM, collectively the group-DIC models) compensate for the solubility bias because of their overly exaggerated primary production, such that biologically driven DIC changes mainly regulate the seasonal cycle of FCO2.

  4. Energy and exergy analysis of a closed Brayton cycle-based combined cycle for solar power tower plants

    International Nuclear Information System (INIS)

    Zare, V.; Hasanzadeh, M.

    2016-01-01

    Highlights: • A novel combined cycle is proposed for solar power tower plants. • The effects of solar subsystem and power cycle parameters are examined. • The proposed combined cycle yields exergy efficiencies of higher than 70%. • For the overall power plant exergy efficiencies of higher than 30% is achievable. - Abstract: Concentrating Solar Power (CSP) technology offers an interesting potential for future power generation and research on CSP systems of all types, particularly those with central receiver system (CRS) has been attracting a lot of attention recently. Today, these power plants cannot compete with the conventional power generation systems in terms of Levelized Cost of Electricity (LCOE) and if a competitive LCOE is to be reached, employing an efficient thermodynamic power cycle is deemed essential. In the present work, a novel combined cycle is proposed for power generation from solar power towers. The proposed system consists of a closed Brayton cycle, which uses helium as the working fluid, and two organic Rankine cycles which are employed to recover the waste heat of the Brayton cycle. The system is thermodynamically assessed from both the first and second law viewpoints. A parametric study is conducted to examine the effects of key operating parameters (including solar subsystem and power cycle parameters) on the overall power plant performance. The results indicate that exergy efficiencies of higher than 30% are achieved for the overall power plant. Also, according to the results, the power cycle proposed in this work has a better performance than the other investigated Rankine and supercritical CO_2 systems operating under similar conditions, for these types of solar power plants.

  5. Catalytic recombination of dissociation products with Pt/SnO2 for rare and common isotope long-life, closed-cycle CO2 lasers

    Science.gov (United States)

    Brown, Kenneth G.; Sidney, B. D.; Schryer, D. R.; Upchurch, B. T.; Miller, I. M.

    1986-01-01

    This paper reports results on recombination of pulsed CO2 laser dissociation products with Pt/SnO2 catalysts, and supporting studies in a surrogate laboratory catalyst reactor. The closed-cycle, pulsed CO2 laser has been continuously operated for one million pulses with an overall power degradation of less than 5 percent by flowing the laser gas mixture through a 2-percent Pt/SnO2 catalyst bed. In the surrogate laboratory reactor, experiments have been conducted to determine isotopic exchange with the catalyst when using rare-isotope gases. The effects of catalyst pretreatment, sample weight, composition, and temperature on catalyst efficiency have also been determined.

  6. Geologic CO2 Sequestration Potential of 42 California Power Plant Sites: A Status Report to WESTCARB

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Katherine B.L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wagoner, J. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2011-06-15

    Forty-two California natural gas combined-cycle (NGCC) power plant sites were evaluated for geologic carbon dioxide (CO2) sequestration potential. The following data were collected in order to gauge the sequestration potential of each power plant site: nearest potential CO2 sink, proximity to oil or gas fi elds, subsurface geology, surface expression of nearby faults, and subsurface water. The data for each site were compiled into a one-page, standalone profi le to serve as a quick reference for future decision-makers. A subset of these data was compiled into a summary table for easy comparison of all 42 sites. Decision-makers will consider the geologic CO2 sequestration potential of each power plant in concert with its CO2 capture potential and will select the most suitable sites for a future carbon capture and storage project. Once the most promising sites are selected, Lawrence Livermore National Laboratory (LLNL) will conduct additional geologic research in order to construct a detailed 3D geologic model for those sites.

  7. Life cycle analysis of photovoltaic cell and wind power plants

    International Nuclear Information System (INIS)

    Uchiyama, Yohji

    1997-01-01

    The paper presents life cycle analyses of net energy and CO 2 emissions on photovoltaic cell and wind power generation plants. Energy requirements associated with a plant are estimated for producing materials, manufacturing equipment, constructing facilities, acid operating plants. Energy ratio and net supplied energy are calculated by the process energy analysis that examines the entire energy inventory of input and output during life time of a plant. Life cycle CO 2 emission can also be calculated from the energy requirements obtained by the net energy analysis. The emission also includes greenhouse effect equivalent to CO 2 emission of methane gas leakage at a mining as well as CO 2 emissions from fossil fuel combustion during generating electricity, natural gas treatment at an extracting well and cement production in industry. The commercially available and future-commercial technologies are dealt with in the study. Regarding PV technologies, two different kinds of installation are investigated; roof-top typed installation of residential houses and ground installation of electric utilities. (author)

  8. CO2 emissions of nuclear electricity generation

    International Nuclear Information System (INIS)

    Wissel, Steffen; Mayer-Spohn, Oliver; Fahl, Ulrich; Blesl, Markus; Voss, Alfred

    2008-01-01

    A survey of LCA studies on nuclear electricity generation revealed life cycle CO 2 emissions ranging between 3 g/kWhe to 60 g/kWhe and above. Firstly, this paper points out the discrepancies in studies by estimating the CO 2 emissions of nuclear power generation. Secondly, the paper sets out to provide critical review of future developments of the fuel cycle for light water reactors and illustrates the impact of uncertainties on the specific CO 2 emissions of nuclear electricity generation. Each step in the fuel cycle will be considered and with regard to the CO 2 emissions analysed. Thereby different assumptions and uncertainty levels are determined for the nuclear fuel cycle. With the impacts of low uranium ore grades for mining and milling as well as higher burn-up rates future fuel characteristics are considered. Sensitivity analyses are performed for all fuel processing steps, for different technical specifications of light water reactors as well as for further external frame conditions. (authors)

  9. Power DRAC for rapid LMFBR deployment and consequent CO2 mitigation

    International Nuclear Information System (INIS)

    Schenewerk, W.E.

    2006-01-01

    A metallic-sodium LMFBR (Liquid Metal Fast Breeder Reactor) can control fuel temperature after a full power SCRAM using natural convection. A 3 percent nominal DRAC (Direct Reactor Auxiliary Cooling) does this without moving parts. DRAC is promoted from tertiary to primary decay heat removal, resulting in what is referred to as a Power DRAC. Power DRAC operates continuously before and after SCRAM, rejecting 3 per cent pile power. Power DRAC operability is validated by having it reject 75 MWt from a 2500 MWt pile at all times. IHX (Intermediate Heat Exchanger) is not required to be operable for primary, secondary, or tertiary core over temperature protection. Original DRAC concept (venturi DRAC) was a 1 per cent nominal tertiary decay heat removal system. Tertiary DRAC patent has expired. Power DRAC rejects 75 MWt through its own secondary sodium heat transfer loop to power a 25 MWe air Brayton cycle. Power DRAC eliminates requiring steam plant operability for decay heat removal. Intermediate sodium heat transfer system and steam plant can be optimized for maximum thermal efficiency. 2.5 GWt pile makes 1.0 GWe net power. Power DRAC maintains pile inlet and outlet temperatures while going from power to post-SCRAM conditions. Steam pressure is maintained post-SCRAM to mitigate SCRAM thermal transient. Not requiring steam plant operability for decay heat removal eases licensing and allows early LMFBR deployment. Each GWe atomic power delays Co2 doubling one week. (author)

  10. PCU arrangement of a supercritical CO{sub 2} cooled micro modular reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Gu; Baik, Seungjoon; Cho, Seong Kuk; Oh, Bong Seong; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    As part of the SMR(Small Modular Reactor)s development effort, the authors propose a concept of supercritical CO{sub 2} (S-CO{sub 2}) cooled fast reactor combined with the S-CO{sub 2} Brayton cycle. The reactor concept is named as KAIST Micro Modular Reactor (MMR). The S-CO{sub 2} Brayton cycle has many strong points when it is used for SMR's power conversion unit. It occupies small footprints due to the compact cycle components and simple layout. Thus, a concept of one module containing the S-CO{sub 2} cooled fast reactor and power conversion system is possible. This module can be shipped via ground transportation (by trailer) or marine transportation. In this study, the authors propose a new conceptual layout for the S-CO{sub 2} cooled direct cycle while considering various issues for arranging cycle components. The new design has an improved cycle efficiency (from 31% to 34%) than the earlier version of MMR by reducing pressure drops in the heat exchangers. As a more efficient option, a recompression recuperated cycle was also designed. It improves 5% of thermal efficiency while 18tons of mass can be added in comparison to the simple recuperated cycle. Even if we adopt recompression cycle as a PCU, the weight of module (152tons) is less than the ground transportable limit (260tons)

  11. Operation Test of the Supercritical CO{sub 2} Compressor Supported with Active Magnetic Bearing

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Jae Eun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cho, Seong Kuk; Lee, Jeong IK [KAIST, Daejeon (Korea, Republic of)

    2016-10-15

    In this paper, the operation test status of the SCIEL sCO{sub 2} AMB Compressor is briefly described. The Supercritical CO{sub 2} Brayton Cycle Integral Experiment Loop (SCIEL) has been installed in Korea Atomic Energy Research Institute (KAERI) to develop the element technologies for the sCO{sub 2} cycle power generation system. The operation of the SCIEL has mainly focused on sCO{sub 2} compressor development and establishing sCO{sub 2} system control logic. The installation of the SCIEL low compression loop was finished in December 2014 and research team succeeded in generating electric power on the supercritical state of the CO{sub 2} in May 2015. The SCIEL has been built in KAERI to develop the element technologies and the system control logics for the sCO{sub 2} cycle power conversion unit of the next generation reactor. For the stable operation of the sCO{sub 2} compressor under high rotational speed, the AMB sCO{sub 2} compressor was developed and achieved the maximum 40,000 rpm.

  12. Life Cycle CO2 Assessment by Block Type Changes of Apartment Housing

    Directory of Open Access Journals (Sweden)

    Cheonghoon Baek

    2016-08-01

    Full Text Available The block type and structural systems in buildings affect the amount of building materials required as well as the CO2 emissions that occur throughout the building life cycle (LCCO2. The purpose of this study was to assess the life cycle CO2 emissions when an apartment housing with ‘flat-type’ blocks (the reference case was replaced with more sustainable ‘T-type’ blocks with fewer CO2 emissions (the alternative case maintaining the same total floor area. The quantity of building materials used and building energy simulations were analyzed for each block type using building information modeling techniques, and improvements in LCCO2 emission were calculated by considering high-strength concrete alternatives. By changing the bearing wall system of the ‘flat-type’ block to the ‘column and beam’ system of the ‘T-type’ block, LCCO2 emissions of the alternative case were 4299 kg-CO2/m2, of which 26% was at the construction stage, 73% was as the operational stage and 1% was at the dismantling and disposal stage. These total LCCO2 emissions were 30% less than the reference case.

  13. Life cycle assessment of rice straw-based power generation in Malaysia

    International Nuclear Information System (INIS)

    Shafie, S.M.; Masjuki, H.H.; Mahlia, T.M.I.

    2014-01-01

    This paper presents an application of LCA (Life Cycle Assessment) with a view to analyzing the environment aspects of rice straw-based power generation in Malaysia. It also compares rice straw-based power generation with that of coal and natural gas. GHG (Greenhouse gas) emission savings were calculated. It finds that rice straw power generation can save GHG (greenhouse gas) emissions of about 1.79 kg CO 2 -eq/kWh compared to coal-based and 1.05 kg CO 2 -eq/kWh with natural gas based power generation. While the development of rice straw-based power generation in Malaysia is still in its early stage, these paddy residues offer a large potential to generate electricity because of their availability. Rice straw power plants not only could solve the problem of removing rice straw from fields without open burning, but also could reduce GHG emissions that contribute to climate change, acidification, and eutrophication, among other environmental problems. - Highlights: • Overall rice straw preparations contribute 224.48 g CO 2 -eq/kg rice straw. • The most constraints due to GHG (greenhouse gas) emission is from transportation. • Distance collection centre to plant less than 110 km to obtains minimum emissions. • Rice straw can save GHG emissions 1.79 kg CO 2 -eq/kWh compared to coal power. • GHG saving 1.05 kg CO 2 -eq/kWh compared to natural gas based power generation

  14. An investigation of sodium–CO{sub 2} interaction byproduct cleaning agent for SFR coupled with S-CO{sub 2} Brayton cycle

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hwa-Young, E-mail: jhy0523@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Division of SFR NSSS System Design, Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Lee, Jeong Ik, E-mail: jeongiklee@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Wi, Myung-Hwan, E-mail: mhwi@kaeri.re.kr [Division of SFR NSSS System Design, Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Ahn, Hong Joo, E-mail: ahjoo@kaeri.re.kr [Division of Nuclear Chemistry Research, Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

    2016-02-15

    Highlights: • Study on cleaning agent was conducted to remove Na–CO{sub 2} interaction byproducts. • Screening criteria to select candidate substances as cleaning agents were suggested. • The mixtures of Na{sub 2}CO{sub 3} with NaBrO{sub 3}, NaClO{sub 3}, or NaBF{sub 4} were thermally analyzed with the TG/DTA studies. • Three candidate substances decomposed before 600 °C and did not react with Na{sub 2}CO{sub 3}. - Abstract: One of the promising future nuclear energy systems, the Sodium-cooled Fast Reactor (SFR) has been actively developed internationally. Recently, to improve safety and economics of a SFR further, coupling supercritical CO{sub 2} power cycle was suggested. However, there can be a chemical reaction between sodium and CO{sub 2} at high temperature (more than 400 °C) when the pressure boundary fails in a sodium–CO{sub 2} heat exchanger. To ensure the performance of such a system, it is important to employ a cleaning agent to recover the system back to normal condition after the reaction. When sodium and CO{sub 2} react, solid and gaseous reaction products such as sodium carbonate (Na{sub 2}CO{sub 3}) and carbon monoxide (CO) appear. Since most of solid reaction products are hard and can deteriorate system performance, quick removal of solid reaction products becomes very important for economic performance of the system. Thus, the authors propose the conceptual method to remove the byproducts with a chemical reaction at high temperature. The chemical reaction will take place between the reaction byproducts and a cleaning agent while the cleaning agent is inert with sodium. Thus, various sodium-based compounds were first investigated and three candidate substances satisfying several criteria were selected; sodium bromate (NaBrO{sub 3}), sodium chlorate (NaClO{sub 3}), and sodium tetrafluoroborate (NaBF{sub 4}). The selected substances were thermally analyzed with the TG/DTA studies. Unfortunately, it was revealed that all candidate

  15. Power and cogeneration technology environomic performance typification in the context of CO2 abatement part II: Combined heat and power cogeneration

    International Nuclear Information System (INIS)

    Li, Hongtao; Marechal, Francois; Favrat, Daniel

    2010-01-01

    This is the second of a series of two articles, dealing with a new approach of environomic (thermodynamic, economic and environmental) performance 'Typification' and optimization of power generation technologies. This part treats specifically of combined heat and power (CHP) cogeneration technologies in the context of CO 2 abatement and provides a methodology for a flexible and fast project based CHP system design evaluation. One of the aspect of the approach is the post-optimization integration of the operating and capital costs, in order to effectively deal with the uncertainty of the project specific design and operation conditions (fuel, electricity and heat selling prices, project financial conditions such as investment amortization periods, annual operating hours, etc). In addition the approach also allows to efficiently evaluate the influence of the external cost such as the CO 2 tax level under a tax scheme or the CO 2 permit price in the emission trading market. Application examples, including gas turbine and combined cycles are treated with the proposed methodology, by using superstructure based generic environomic models and a multi-objective optimizer.

  16. Studies of super-critical CO2 gas turbine power generation fast reactor (Contract research, translated document)

    International Nuclear Information System (INIS)

    Kisohara, Naoyuki; Kotake, Shoji; Sakamoto, Toshihiko

    2008-08-01

    The following studies have been executed for a super-critical CO 2 turbine system of an SFR. (1) Preliminary design of a SFR adopting a super-critical CO 2 cycle turbine. Preliminary system design of an SFR that adopts a super-critical CO 2 cycle turbine has been made. This SFR system eliminates secondary sodium circuits because of no sodium/water reaction. The power generation efficiency of the SFR has been estimated to be approximately 42%. Compared to a conventional SFR that adopts a steam Rankine cycle with secondary sodium circuits, the volume of the reactor building of the SC-CO 2 SFR has been reduced by 20%. (2) Thermal-hydraulic experiment of a super-critical CO 2 cycle loop. A test loop that simulates a super-critical CO 2 whole cycle was fabricated. An electrical heater was used for a heat source of the test loop. The high efficiency of the compressor has been experimentally confirmed near the super-critical region. The temperature efficiencies of PCHE recuperators have been approximately 98-99% (hot leg), and the recuperators have exhibited high heat transfer performance. No significant flow instability has been observed in the test loop operation. (3) Liquid sodium/CO 2 reaction test. Reaction tests have been executed by contacting a small amount of liquid sodium and CO 2 gas. Continuous sodium/CO 2 reactions with flame have occurred at the temperature higher than 570-580degC. Main reaction products have been Na 2 CO 3 and CO gas. The reaction heat has been also measured to be 50-75kJ/Na-mol. (4) Computer code safety analysis for tube failure of sodium/CO 2 heat exchanger. Safety calculation has been done for one double ended guillotine tube failure (1 DEG) of a helical coil type sodium/CO 2 heat exchanger. The analysis has showed that the maximum pressure in the primary sodium circuit is 0.28MPa due to a gas leak. It has been, however, below the allowed level of the primary circuit structural integrity. The void reactivity of the reactor core has

  17. Comparative analysis of supercritical CO2 power conversion system control schemes

    International Nuclear Information System (INIS)

    Vilim, R.B.; Moisseytsev, A.

    2008-01-01

    A comparative analysis of control system performance was carried out for the S-CO 2 re-compressing cycle. In this study two control strategies were developed for managing process variables for a change in load at the electrical generator. Both relied on inventory control to reduce power but differed in other significant respects. In inventory control turbomachine mass flow rates are reduced through density change with the goal of preserving velocity triangle similarity and, hence, cycle efficiency. An inventory and low temperature control scheme was operated to maintain a trajectory that avoids close approach to the critical point by controlling the main compressor inlet temperature. Shaft power tracks a setpoint by controlling density. This control scheme may be preferred in plant configurations that use a flow-split. There the rapid density change with pressure near the critical point can lead to flow rate instability. An inventory and turbine bypass control scheme was operated to more closely approach the critical point. Inventory in addition to turbine bypass was used to control shaft power. The first control scheme yielded greater efficiency at reduced power as a result of two factors. First, bypassing coolant around the turbine increases the mass flow rate through the compressors while shaft speed is maintained constant. As a result the compressor velocity triangles are altered from their peak efficiency values. Second, the bypass flow rate results in non-isothermal mixing downstream where the turbine and bypass flow combine which also penalizes efficiency. (authors)

  18. Analysis of the Global Warming Potential of Biogenic CO2 Emission in Life Cycle Assessments.

    Science.gov (United States)

    Liu, Weiguo; Zhang, Zhonghui; Xie, Xinfeng; Yu, Zhen; von Gadow, Klaus; Xu, Junming; Zhao, Shanshan; Yang, Yuchun

    2017-01-03

    Biomass is generally believed to be carbon neutral. However, recent studies have challenged the carbon neutrality hypothesis by introducing metric indicators to assess the global warming potential of biogenic CO 2 (GWP bio ). In this study we calculated the GWP bio factors using a forest growth model and radiative forcing effects with a time horizon of 100 years and applied the factors to five life cycle assessment (LCA) case studies of bioproducts. The forest carbon change was also accounted for in the LCA studies. GWP bio factors ranged from 0.13-0.32, indicating that biomass could be an attractive energy resource when compared with fossil fuels. As expected, short rotation and fast-growing biomass plantations produced low GWP bio . Long-lived wood products also allowed more regrowth of biomass to be accounted as absorption of the CO 2 emission from biomass combustion. The LCA case studies showed that the total life cycle GHG emissions were closely related to GWP bio and energy conversion efficiency. By considering the GWP bio factors and the forest carbon change, the production of ethanol and bio-power appeared to have higher GHG emissions than petroleum-derived diesel at the highest GWP bio .

  19. Analysis of the Global Warming Potential of Biogenic CO2 Emission in Life Cycle Assessments

    Science.gov (United States)

    Liu, Weiguo; Zhang, Zhonghui; Xie, Xinfeng; Yu, Zhen; von Gadow, Klaus; Xu, Junming; Zhao, Shanshan; Yang, Yuchun

    2017-01-01

    Biomass is generally believed to be carbon neutral. However, recent studies have challenged the carbon neutrality hypothesis by introducing metric indicators to assess the global warming potential of biogenic CO2 (GWPbio). In this study we calculated the GWPbio factors using a forest growth model and radiative forcing effects with a time horizon of 100 years and applied the factors to five life cycle assessment (LCA) case studies of bioproducts. The forest carbon change was also accounted for in the LCA studies. GWPbio factors ranged from 0.13–0.32, indicating that biomass could be an attractive energy resource when compared with fossil fuels. As expected, short rotation and fast-growing biomass plantations produced low GWPbio. Long-lived wood products also allowed more regrowth of biomass to be accounted as absorption of the CO2 emission from biomass combustion. The LCA case studies showed that the total life cycle GHG emissions were closely related to GWPbio and energy conversion efficiency. By considering the GWPbio factors and the forest carbon change, the production of ethanol and bio-power appeared to have higher GHG emissions than petroleum-derived diesel at the highest GWPbio. PMID:28045111

  20. High Materials Performance in Supercritical CO2 in Comparison with Atmospheric Pressure CO2 and Supercritical Steam

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Gordon [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Tylczak, Joseph [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Carney, Casey [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Dogan, Omer N. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

    2017-02-26

    This presentation covers environments (including advanced ultra-supercritical (A-USC) steam boiler/turbine and sCO2 indirect power cycle), effects of pressure, exposure tests, oxidation results, and mechanical behavior after exposure.

  1. Structural and thermal stabilities of layered Li(Ni 1/3Co 1/3Mn 1/3)O 2 materials in 18650 high power batteries

    Science.gov (United States)

    He, Yan-Bing; Ning, Feng; Yang, Quan-Hong; Song, Quan-Sheng; Li, Baohua; Su, Fangyuan; Du, Hongda; Tang, Zhi-Yuan; Kang, Feiyu

    The structural and thermal stabilities of the layered Li(Ni 1/3Co 1/3Mn 1/3)O 2 cathode materials under high rate cycling and abusive conditions are investigated using the commercial 18650 Li(Ni 1/3Co 1/3Mn 1/3)O 2/graphite high power batteries. The Li(Ni 1/3Co 1/3Mn 1/3)O 2 materials maintain their layered structure even when the power batteries are subjected to 200 cycles with 10 C discharge rate at temperatures of 25 and 50 °C, whereas their microstructure undergoes obvious distortion, which leads to the relatively poor cycling performance of power batteries at high charge/discharge rates and working temperature. Under abusive conditions, the increase in the battery temperature during overcharge is attributed to both the reactions of electrolyte solvents with overcharged graphite anode and Li(Ni 1/3Co 1/3Mn 1/3)O 2 cathode and the Joule heat that results from the great increase in the total resistance (R cell) of batteries. The reactions of fully charged Li(Ni 1/3Co 1/3Mn 1/3)O 2 cathodes and graphite anodes with electrolyte cannot be activated during short current test in the fully charged batteries. However, these reactions occur at around 140 °C in the fully charged batteries during oven test, which is much lower than the temperature of about 240 °C required for the reactions outside batteries.

  2. CO{sub 2} capture behavior of shell during calcination/carbonation cycles

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.J.; Zhao, C.S.; Chen, H.C.; Duan, L.B.; Chen, X.P. [School of Energy and Environment, Southeast University, Nanjing (China)

    2009-08-15

    The cyclic carbonation performances of shells as CO{sub 2} sorbents were investigated during multiple calcination/carbonation cycles. The carbonation kinetics of the shell and limestone are similar since they both exhibit a fast kinetically controlled reaction regime and a diffusion controlled reaction regime, but their carbonation rates differ between these two regions. Shell achieves the maximum carbonation conversion for carbonation at 680-700 C. The mactra veneriformis shell and mussel shell exhibit higher carbonation conversions than limestone after several cycles at the same reaction conditions. The carbonation conversion of scallop shell is slightly higher than that of limestone after a series of cycles. The calcined shell appears more porous than calcined limestone, and possesses more pores >230 nm, which allow large CO{sub 2} diffusion-carbonation reaction rates and higher conversion due to the increased surface area of the shell. The pores of the shell that are greater than 230 nm do not sinter significantly. The shell has more sodium ions than limestone, which probably leads to an improvement in the cyclic carbonation performance during the multiple calcination/carbonation cycles. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  3. A novel approach for treatment of CO{sub 2} from fossil fired power plants, Part A: The integrated systems ITRPP

    Energy Technology Data Exchange (ETDEWEB)

    Minutillo, M.; Perna, A. [Department of Industrial Engineering, University of Cassino, Via G. di Biasio, 43, 03043 Cassino, Frosinone (Italy)

    2009-05-15

    The environmental issues, due to the global warming caused by the rising concentration of greenhouse gases in the atmosphere, require new strategies aimed to increase power plants efficiencies and to reduce CO{sub 2} emissions. This two-paper work focuses on a different approach for capture and reduction of CO{sub 2} from flue gases of fossil fired power plant, with respect to conventional post-combustion technologies. This approach consists of flue gases utilization as co-reactants in a catalytic process, the tri-reforming process, to generate a synthesis gas suitable in chemical and energy industries (methanol, DME, etc.). In fact, the further conversion of syngas to a transportation fuel, such as methanol, is an attractive solution to introduce near zero-emission technologies (i.e. fuel cells) in vehicular applications. In this Part A, integrated systems for co-generation of electrical power and synthesis gas useful for methanol production have been defined and their performance has been investigated considering different flue gases compositions. In Part B, in order to verify the environmental advantages and energy suitability of these systems, their comparison with conventional technology for methanol production is carried out. The integrated systems (ITRPP, Integrated Tri-Reforming Power Plant) consist of a power island, based on a thermal power plant, and a methane tri-reforming island in which the power plants' exhausts react with methane to produce a synthesis gas used for methanol synthesis. As power island, a steam turbine power plant fuelled with coal and a gas turbine combined cycle fuelled with natural gas have been considered. The energy and environmental analysis of ITRPP systems (ITRPP-SC and ITRPP-CC) has been carried out by using thermochemical and thermodynamic models which have allowed to calculate the syngas composition, to define the energy and mass balances and to estimate the CO{sub 2} emissions for each ITRPP configuration. The

  4. Eigendecomposition model of resistance temperature detector with applications to S-CO{sub 2} cycle sensing

    Energy Technology Data Exchange (ETDEWEB)

    Heifetz, Alexander, E-mail: aheifetz@anl.gov; Vilim, Richard

    2017-01-15

    Highlights: • Developed eigendecomposition model of resistance temperature detector (RTD) in a fluid. • Showed that RTD time constant primarily depends on the rate of heat transfer from the fluid to the outer wall of RTD. • Showed that RTD time constant can be calculated as the sum of reciprocal eigenvalues of the heat transfer matrix. • Calculated time constant of thermowell-mounted RTD sensor at the hot side of the precooler in the S-CO{sub 2} cycle. - Abstract: Super-critical carbon dioxide (S-CO{sub 2}) is a promising thermodynamic cycle for advanced nuclear reactors and solar energy conversion applications. Dynamic control of the proposed recompression S-CO{sub 2} cycle is accomplished with input from resistance temperature detector (RTD) measurements of the process fluid. One of the challenges in practical implementation of S-CO{sub 2} cycle is high corrosion rate of component and sensor materials. In this paper, we develop a mathematical model of RTD sensing using eigendecomposition model of radial heat transfer in a layered long cylinder. We show that the value of RTD time constant primarily depends on the rate of heat transfer from the fluid to the outer wall of RTD. We also show that for typical material properties, RTD time constant can be calculated as the sum of reciprocal eigenvalues of the heat transfer matrix. Using the computational model and a set of RTD and CO{sub 2} fluid thermo-physical parameter values, we calculate the value of time constant of thermowell-mounted RTD sensor at the hot side of the precooler in the S-CO{sub 2} cycle. The eigendecomposition model of RTD will be used in future studies to model sensor degradation and its impact on control of S-CO{sub 2}.

  5. Combined Cycle Power Generation Employing Pressure Gain Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Holley, Adam [United Technologies Corporation, East Hartford, CT (United States). Research Center

    2017-05-15

    The Phase I program assessed the potential benefit of applying pressure gain combustion (PGC) technology to a natural gas combined cycle power plant. A conceptual design of the PGC integrated gas turbine was generated which was simulated in a detailed system modeling tool. The PGC integrated system was 1.93% more efficient, produced 3.09% more power, and reduced COE by 0.58%. Since the PGC system used had the same fuel flow rate as the baseline system, it also reduced CO2 emissions by 3.09%. The PGC system did produce more NOx than standard systems, but even with the performanceand cost penalties associated with the cleanup system it is better in every measure. This technology benefits all of DOE’s stated program goals to improve plant efficiency, reduce CO2 production, and reduce COE.

  6. Studying heat integration options for steam-gas power plants retrofitted with CO2 post-combustion capture

    International Nuclear Information System (INIS)

    Carapellucci, Roberto; Giordano, Lorena; Vaccarelli, Maura

    2015-01-01

    Electricity generation from fossil fuels has become a focal point of energy and climate change policies due to its central role in modern economics and its leading contribution to greenhouse gas emissions. Carbon capture and sequestration (CCS) is regarded by the International Energy Agency as an essential part of the technology portfolio for carbon mitigation, as it can significantly reduce CO 2 emissions while ensuring electricity generation from fossil fuel power plants. This paper studies the retrofit of natural gas combined cycles (NGCCs) with an amine-based post-combustion carbon capture system. NGCCs with differently rated capacities were analysed under the assumptions that the heat requirement of the capture system was provided via a steam extraction upstream of the low-pressure steam turbine or by an auxiliary unit that was able to reduce the power plant derating related to the energy needs of the CCS system. Different types of auxiliary units were investigated based on power plant size, including a gas turbine cogeneration plant and a supplementary firing unit or boiler fed by natural gas or biomass. Energy and economic analyses were performed in order to evaluate the impact of type and layout of retrofit option on energy, environmental and economic performance of NGCCs with the CCS system. - Highlights: • Steam-gas power plants with an amine-based CO 2 capture unit are examined. • The study concerns three combined cycles with different capacity and plant layout. • Several options to fulfil the heat requirement of the CCS system are explored. • Steam extraction significantly reduces the capacity of steam-gas power plant. • An auxiliary combined heat and power unit allows to reduce power plant derating

  7. CO2 Price Impacts on Nuclear Power Plant Competitiveness in Croatia

    International Nuclear Information System (INIS)

    Tomsic, Z.; Pasicko, R.

    2010-01-01

    Long term power system planning faces growing number of concerns and uncertainties, which is especially true for nuclear power plants due to their high investment costs and financial risk. In order to analyze competitiveness of nuclear power plants and optimize energy mix, existing models are not sufficient anymore and planners need to think differently in order to face these challenges. Croatia will join EU ETS (European Emission Trading Scheme) with accession to EU (probably in 2012). Thus, for Croatian electrical system it is very important to analyze possible impacts of CO 2 emissions. Analysis presented in this paper is done by electricity market simulation model PLEXOS which was used for modelling Croatian electrical system during development of the Croatian Energy Strategy in 2008. Paper analyzes impacts of CO 2 price on competitiveness of nuclear power plant within Croatian power system between 2020 and 2025. Analyzes are focused on how nuclear power plant influences total emission from the power system regarding coal and gas prices, average electricity price regarding CO 2 , coal and gas prices price. Results of this paper are showing that with emissions from Energy strategy development scenario with two new coal power plants (600 MW each) and two new gas power plants (400 MW each) until 2020, Croatia does not meet Kyoto target due to this emissions from power system. On the other side, introduction of nuclear power plants presented in this paper (1000 MW instead of one coal and one gas power plant) means nearly 6.5 Mt CO 2 emissions less annually and gives possibility to achieve Kyoto target (as this reduced amount represents nearly 22 % of Croatian Kyoto target). Results are also showing how increase in CO 2 price is enhancing competitiveness of a nuclear power plant.(author).

  8. Evaluation of lifecycle CO2 emissions from the Japanese electric power sector in the 21st century under various nuclear scenarios

    International Nuclear Information System (INIS)

    Tokimatsu, Koji; Kosugi, Takanobu; Asami, Takayoshi; Williams, Eric; Kaya, Yoichi

    2006-01-01

    The status and prospects of the development of Japanese nuclear power are controversial and uncertain. Many deem that nuclear power can play key roles in both supplying energy and abating CO 2 emissions; however, due to severe nuclear accidents, public acceptance of nuclear power in Japan has not been fully obtained. Moreover, deregulation and liberalization of the electricity market impose pressure on large Japanese electric power companies with regard to both the operation of nuclear power plants and the development of the nuclear fuel cycle. Long-term Japanese CO 2 reduction strategies up to 2100 are of environmental concern and are socially demanded under the circumstances described above. Taking these factors into account, we set the following two objectives for this study. One is to estimate lifecycle CO 2 (LCCO 2 ) emissions from Japanese nuclear power, and the other is to evaluate CO 2 emissions from the Japanese electric power sector in the 21st century by quantifying the relationship between LCCO 2 emissions and scenarios for the adoption of nuclear power. In the pursuit of the above objectives, we first create four scenarios of Japanese adoption of nuclear power, that range from nuclear power promotion to phase-out. Next, we formulate four scenarios describing the mix of the total electricity supply in Japan till the year 2100 corresponding to each of these nuclear power scenarios. CO 2 emissions from the electric power sector in Japan till the year 2100 are estimated by summing those generated by each respective electric power technology and LCCO 2 emission intensity. The LCCO 2 emission intensity of nuclear power for both light water reactors (LWR) and fast breeder reactors (FBR) includes the uranium fuel production chain, facility construction/operation/decommission, and spent fuel processing/disposal. From our investigations, we conclude that the promotion of nuclear power is clearly a strong option for reducing CO 2 emissions by the electric power

  9. Power cycle heat balance software for personal computer (PC)2TM

    International Nuclear Information System (INIS)

    Bockh, P. von; Rodriguez, H.

    1996-01-01

    This paper describes the PC-based power cycle balance of plant software (PC)trademark (Power Cycle on Personal Computer). It is designed to assist nuclear, fossil, and industrial power plants so that steam cycles can be simulated, analyzed and optimized. First, the cycle model is developed on the screen. The elements of the power cycle are taken from a tool box containing all components of a modern power cycle. The elements are connected by using a mouse. The next step is the input of the design values of the components or data taken from performance tests. This entire input sequence is guided by the program. Based on the input data, the physical behavior of each component is simulated according to established physical rules. Part load operation or other off-design conditions can be calculated. The program is designed for use by power plant engineers and power engineering firms to optimize new power cycles, perform problem-solving analyses, optimize component retrofit, and train power plant engineers and operators. It also can be used by universities to educate engineering students

  10. Co-operation of the CMEA member countries in the developing power reactors of various types, including some aspects of their nuclear fuel cycles

    International Nuclear Information System (INIS)

    Barbur, I.; Barchenkov, A.; Molnar, L; Panasenkov, A.; Tolpygo, V.; Hake, V.; Shcherbinin, B.

    1977-01-01

    The report gives an account of the problems of projected development of atomic power and evaluates its role in the fuel and power complex and long-range development of interconnected power systems of the CMEA member countries. The report emphasizes the importance of scientific and technical co-operation in the creation of power reactors on thermal and fast neutrons with 1000-1500 MW unit electric capacity as well as in the elaboration of nuclear plants for heating services. It notes the positive experience of the International scientific and research group of scientists of the CMEA member countries carrying out reactor-physical studies on the critical assembly and its contribution to the elaboration of power reactors. The report contains basic conclusions from the development forecast for nuclear power of the CMEA member countries up to 1990 including forecasting methodology; role of nuclear power plants in saving natural and enriched uranium for a projected period; impact of nuclear power development rates on its structure (thermal and fast reactor ratio); relation between the beginning of mass commissioning of nuclear power plants with fast reactors and the integral demand for nuclear fuel; scale of required capacities of fuel cycle services; time dependence of fuel cycle on nuclear fuel requirements. It examines the problems and lists the results of scientific and technical co-operation of the CMEA member countries in the field of fuel cycle, including the transport of spent nuclear fuel, its recovery, reprocessing and radioactive waste disposal. Particular questions of co-operation of the CMEA member countries to secure radiation safety of nuclear power plants and environmental protection are analyzed. The report notes the role of international economic associations - ''Interatomenergo'' and ''Interatominstrument'' - in the accelerated development of nuclear power on the basis of cooperation and specialization in the manufacture of equipment for nuclear power

  11. Adoption of nitrogen power conversion system for small scale ultra-long cycle fast reactor eliminating intermediate sodium loop

    International Nuclear Information System (INIS)

    Seo, Seok Bin; Seo, Han; Bang, In Cheol

    2016-01-01

    Highlights: • N 2 power conversion system for both safety and thermal performance aspects. • Sensitivity studies of several controlled parameters on N 2 power conversion system. • The elimination of the intermediate loop increased the cycle thermal efficiency. • The elimination of the intermediate loop expects economic advantages. - Abstract: As one of SFRs, the ultra-long cycle fast reactor with a power rating of 100 MW e (UCFR-100) was introduced for a 60-year operation. As an alternative to the traditional steam Rankine cycle for the power conversion system, gas based Brayton cycle has been considered for UCFR-100. Among Supercritical CO 2 (S-CO 2 ), Helium (He), Nitrogen (N 2 ) as candidates for the power conversion system for UCFR-100, an N 2 power conversion system was chosen considering both safety and thermal performance aspects. The elimination of the intermediate sodium loop could be achieved due to the safety and stable characteristics of nitrogen working fluid. In this paper, sensitivity studies with respect to several controlled parameters on N 2 power conversion system were performed to optimize the system. Furthermore, the elimination of the intermediate loop was evaluated with respect to its impact on the thermodynamic performance and other aspects.

  12. Fluidized-Bed Heat Transfer Modeling for the Development of Particle/Supercritical-CO2 Heat Exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Zhiwen [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Martinek, Janna G [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-06-03

    Concentrating solar power (CSP) technology is moving toward high-temperature and high-performance design. One technology approach is to explore high-temperature heat-transfer fluids and storage, integrated with a high-efficiency power cycle such as the supercritical carbon dioxide (s-CO2) Brayton power cycle. The s-CO2 Brayton power system has great potential to enable the future CSP system to achieve high solar-to-electricity conversion efficiency and to reduce the cost of power generation. Solid particles have been proposed as a possible high-temperature heat-transfer medium that is inexpensive and stable at high temperatures above 1,000 degrees C. The particle/heat exchanger provides a connection between the particles and s-CO2 fluid in the emerging s-CO2 power cycles in order to meet CSP power-cycle performance targets of 50% thermal-to-electric efficiency, and dry cooling at an ambient temperature of 40 degrees C. The development goals for a particle/s-CO2 heat exchanger are to heat s-CO2 to =720 degrees C and to use direct thermal storage with low-cost, stable solid particles. This paper presents heat-transfer modeling to inform the particle/s-CO2 heat-exchanger design and assess design tradeoffs. The heat-transfer process was modeled based on a particle/s-CO2 counterflow configuration. Empirical heat-transfer correlations for the fluidized bed and s-CO2 were used in calculating the heat-transfer area and optimizing the tube layout. A 2-D computational fluid-dynamics simulation was applied for particle distribution and fluidization characterization. The operating conditions were studied from the heat-transfer analysis, and cost was estimated from the sizing of the heat exchanger. The paper shows the path in achieving the cost and performance objectives for a heat-exchanger design.

  13. A numerical investigation of the sCO2 recompression cycle off-design behaviour, coupled to a sodium cooled fast reactor, for seasonal variation in the heat sink temperature

    International Nuclear Information System (INIS)

    Floyd, J.; Alpy, N.; Moisseytsev, A.; Haubensack, D.; Rodriguez, G.; Sienicki, J.; Avakian, G.

    2013-01-01

    Highlights: • Year-round behaviour of the supercritical CO 2 recompression cycle is simulated. • Behaviour of the system was uncertain due to large changes in the fluid properties. • Cycle thermodynamic optimisation and component preliminary designs were performed. • No off design cycle stability issues, compressors operate away from surge region. • Independent speed control of compressors maintains power and cycle efficiency. -- Abstract: Supercritical CO 2 cycles are particularly attractive for Generation IV Sodium-Cooled Fast Reactors (SFRs) as they can be simple and compact, but still offer steam-cycle equivalent efficiency while also removing potential for Na/H 2 O reactions. However, CO 2 thermophysical properties are very sensitive close to the critical point which raises, in particular, questions about the compressor and so cycle off-design behaviour when subject to inevitable temperature increases that result from seasonal variations in the heat sink temperature. This publication reports the numerical investigation of such an issue that has been performed using the Plant Dynamics Code (ANL, USA), the cycle being optimised for the next French SFR, ASTRID (1500 MW th ), as a test-case. On design, the net plant efficiency is 42.2% for a high pressure (25 MPa) turbine with an inlet temperature of 515 °C and considering a cycle low temperature of 35 °C. The off-design cycle behaviour is studied based on preliminary designs for the main components and assuming the use of a fixed heat sink flow rate. First results obtained using a common fixed shaft speed for all turbomachines, without any other active control, show no stability issues and roughly constant density (and volumetric flow rate) at the main compressor inlet for the range of heat sink temperature considered (21–40 °C). This occurs because the new stationary states are found without requiring a significant shift of mass to the higher pressure level, meaning the compressor inlet pressure

  14. Evaluation of the energy efficiency of combined cycle gas turbine. Case study of Tashkent thermal power plant, Uzbekistan

    International Nuclear Information System (INIS)

    Aminov, Zarif; Nakagoshi, Nobukazu; Xuan, Tran Dang; Higashi, Osamu; Alikulov, Khusniddin

    2016-01-01

    Highlights: • The combined cycle power plant (CCPP) has a steam turbine and a gas turbine. • Fossil fuel savings and reduction of the CCGT of was evaluated. • The performance of a three pressure CCGT is modelled under different modes. • Energy efficiency of the combined cycle was 58.28%. • An annual reduction of 1760.18 tNO_x/annum and 981.25 ktCO_2/annum can be achieved. - Abstract: The power generation of Tashkent Thermal Power Plant (TPP) is based on conventional power units. Moreover, the facility suffers from limited efficiency in electricity generation. The plant was constructed during the Soviet era. Furthermore, the power plant is being used for inter-hour power generation regulation. As a result, the efficiency can be reduced by increasing specific fuel consumption. This research focuses on the evaluation of the energy efficiency of the combined cycle gas turbine (CCGT) for the Tashkent TPP. Specifically, the objective is an evaluation of fossil fuel savings and reduction of CO_2 and NO_x emissions with the using CCGT technology at conventional power plant. The proposed combined cycle power plant (CCPP) includes an existing steam turbine (ST) with 160 MW capacity, heat recovery steam generator (HRSG), and gas turbine (GT) technology with 300 MW capacity. The performance of a three pressure CCGT is modelled under different modes. As a result, the efficiency of the combined cycle was evaluated at 58.28%, while the conventional cycle had an efficiency of 34.5%. We can achieve an annual reduction of 1760.18 tNO_x/annum and 981.25 ktCO_2/annum.

  15. Technology options for clean coal power generation with CO2 capture

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Song; Bergins, Christian; Kikkawa, Hirofumi; Kobayashi, Hironobu; Kawasaki, Terufumi

    2010-09-15

    The state-of-the-art coal-fired power plant today is about 20% more efficient than the average operating power plants, and can reduce emissions such as SO2, NOx, and mercury to ultra-low levels. Hitachi is developing a full portfolio of clean coal technologies aimed at further efficiency improvement, 90% CO2 reduction, and near-zero emissions, including 700 deg C ultrasupercritical boilers and turbines, post-combustion CO2 absorption, oxyfuel combustion, and IGCC with CCS. This paper discusses the development status, performance and economic impacts of these technologies with focus on post combustion absorption and oxyfuel combustion - two promising CO2 solutions for new and existing power plants.

  16. High-powered CO2 -lasers and noise control

    Science.gov (United States)

    Honkasalo, Antero; Kuronen, Juhani

    High-power CO2 -lasers are being more and more widely used for welding, drilling and cutting in machine shops. In the near future, different kinds of surface treatments will also become routine practice with laser units. The industries benefitting most from high power lasers will be: the automotive industry, shipbuilding, the offshore industry, the aerospace industry, the nuclear and the chemical processing industries. Metal processing lasers are interesting from the point of view of noise control because the working tool is a laser beam. It is reasonable to suppose that the use of such laser beams will lead to lower noise levels than those connected with traditional metal processing methods and equipment. In the following presentation, the noise levels and possible noise-control problems attached to the use of high-powered CO2 -lasers are studied.

  17. Development of high power pulsed CO2 laser

    International Nuclear Information System (INIS)

    Nakai, Sadao; Matoba, Masafumi; Fujita, Hisanori; Daido, Hiroyuki; Inoue, Mitsuo

    1982-01-01

    The inertial nuclear fusion research using pellet implosion has rapidly progressed accompanying laser technique improvement and output increase. As the high output lasers for this purpose, Nd glass lasers or CO 2 lasers are used. The CO 2 lasers possess the characteristics required as reactor lasers, i.e., high efficiency, high frequency repetition, possibility of scale-up and economy. So, the technical development of high power CO 2 lasers assuming also as reactor drivers has been performed at a quick pace together with the research on the improvement of efficiency of pellet implosion by 10 μm laser beam. The Institute of Laser Engineering, Osaka University, stated to build a laser system LEKKO No. 8 of 8 beams and 10 kJ based on the experiences in laser systems LEKKO No. 1 and LEKKO No. 2, and the system LEKKO No. 8 was completed in March, 1981. The operation tests for one year since then has indicated as the laser characteristics that the system performance was as designed initially. This paper reviews the structure, problems and present status of the large scale CO 2 lasers. In other words, the construction of laser system, CO 2 laser proper, oscillator, booster amplifier, prevention of parasitic oscillation, non-linear pulse propagation and fairing of output pulse form, system control and beam alignment, and high power problems are described. The results obtained are to be reported in subsequent issues. (Wakatsuki, Y.)

  18. A Review of Hazardous Chemical Species Associated with CO2 Capturefrom Coal-Fired Power Plants and Their Potential Fate in CO2 GeologicStorage

    Energy Technology Data Exchange (ETDEWEB)

    Apps, J.A.

    2006-02-23

    Conventional coal-burning power plants are major contributors of excess CO2 to the atmospheric inventory. Because such plants are stationary, they are particularly amenable to CO2 capture and disposal by deep injection into confined geologic formations. However, the energy penalty for CO2 separation and compression is steep, and could lead to a 30-40 percent reduction in useable power output. Integrated gas combined cycle (IGCC) plants are thermodynamically more efficient, i.e.,produce less CO2 for a given power output, and are more suitable for CO2 capture. Therefore, if CO2 capture and deep subsurface disposal were to be considered seriously, the preferred approach would be to build replacement IGCC plants with integrated CO2 capture, rather than retrofit existing conventional plants. Coal contains minor quantities of sulfur and nitrogen compounds, which are of concern, as their release into the atmosphere leads to the formation of urban ozone and acid rain, the destruction of stratospheric ozone, and global warming. Coal also contains many trace elements that are potentially hazardous to human health and the environment. During CO2 separation and capture, these constituents could inadvertently contaminate the separated CO2 and be co-injected. The concentrations and speciation of the co-injected contaminants would differ markedly, depending on whether CO2 is captured during the operation of a conventional or an IGCC plant, and the specific nature of the plant design and CO2 separation technology. However, regardless of plant design or separation procedures, most of the hazardous constituents effectively partition into the solid waste residue. This would lead to an approximately two order of magnitude reduction in contaminant concentration compared with that present in the coal. Potential exceptions are Hg in conventional plants, and Hg and possibly Cd, Mo and Pb in IGCC plants. CO2 capture and injection disposal could afford an opportunity to deliberately capture

  19. Coupled nutrient cycling determines tropical forest trajectory under elevated CO2.

    Science.gov (United States)

    Bouskill, N.; Zhu, Q.; Riley, W. J.

    2017-12-01

    Tropical forests have a disproportionate capacity to affect Earth's climate relative to their areal extent. Despite covering just 12 % of land surface, tropical forests account for 35 % of global net primary productivity and are among the most significant of terrestrial carbon stores. As atmospheric CO2 concentrations increase over the next century, the capacity of tropical forests to assimilate and sequester anthropogenic CO2 depends on limitation by multiple factors, including the availability of soil nutrients. Phosphorus availability has been considered to be the primary factor limiting metabolic processes within tropical forests. However, recent evidence points towards strong spatial and temporal co-limitation of tropical forests by both nitrogen and phosphorus. Here, we use the Accelerated Climate Modeling for Energy (ACME) Land Model (ALMv1-ECA-CNP) to examine how nutrient cycles interact and affect the trajectory of the tropical forest carbon sink under, (i) external nutrient input, (ii) climate (iii) elevated CO2, and (iv) a combination of 1-3. ALMv1 includes recent theoretical advances in representing belowground competition between roots, microbes and minerals for N and P uptake, explicit interactions between the nitrogen and phosphorus cycles (e.g., phosphatase production and nitrogen fixation), the dynamic internal allocation of plant N and P resources, and the integration of global datasets of plant physiological traits. We report nutrient fertilization (N, P, N+P) predictions for four sites in the tropics (El Verde, Puerto Rico, Barro Colorado Island, Panama, Manaus, Brazil and the Osa Peninsula, Coast Rica) to short-term nutrient fertilization (N, P, N+P), and benchmarking of the model against a meta-analysis of forest fertilization experiments. Subsequent simulations focus on the interaction of the carbon, nitrogen, and phosphorus cycles across the tropics with a focus on the implications of coupled nutrient cycling and the fate of the tropical

  20. Cycling-induced degradation of LiCoO2 thin-film cathodes at elevated temperature

    International Nuclear Information System (INIS)

    Van Sluytman, J.S.; West, W.C.; Whitacre, J.F.; Alamgir, F.M.; Greenbaum, S.G.

    2006-01-01

    The cycle life of LiCoO 2 -based all solid-state thin-film cells has been studied at room temperature, and at elevated temperatures of 50, 100, and 150 deg. C. X-ray diffraction, as well as Raman analysis, has been used to complement the electrochemical data in examining structural and chemical changes. XRD and Raman spectroscopy data indicate that elevated temperature soaks of the thin-film batteries in the quiescent state causes no discernable changes in the LiCoO 2 cathode layer. However, when the thin-film batteries are cycled at elevated temperatures, decreases in average grain size of the LiCoO 2 film occur with dramatic concomitant charge and discharge capacity loss

  1. Full synergistic effect of hydrothermal NiCo2O4 nanosheets/CuCo2O4 nanocones supported on Ni foam for high-performance asymmetric supercapacitors

    Science.gov (United States)

    Wen, Shiyang; Liu, Yu; Bai, Hongye; Shao, Rong; Xu, Wei; Shi, Weidong

    2018-06-01

    In this work, a series of NiCo2O4/CuCo2O4 composites were prepared by a two-step hydrothermal method. The optimized NiCo2O4/CuCo2O4 electrode shows more than 5 times area capacitance (4.97 F cm-2) than pure NiCo2O4 at the current density of 1 mA cm-2. The best performance of sample assembled an asymmetric supercapacitor could reach up to 42 F g-1 at the current density of 1 A g-1. In addition, the maximum energy density of 15 W h kg-1 was achieved with the power density of 814 W kg-1. The as-prepared active electrode material also reveals excellent cycling stability with 90.6% capacitance retention after 5000 cycles. These results indicate potential application in developing energy storage devices with high energy density power density.

  2. Research on catalysts for long-life closed-cycle CO2 laser oaperation

    Science.gov (United States)

    Sidney, Barry D.; Schryer, David R.; Upchurch, Billy T.; Hess, Robert V.; Wood, George M.

    1987-01-01

    Long-life, closed-cycle operation of pulsed CO2 lasers requires catalytic CO-O2 recombination both to remove O2, which is formed by discharge-induced CO2 decomposition, and to regenerate CO2. Platinum metal on a tin-oxide substrate (Pt/SnO2) has been found to be an effective catalyst for such recombination in the desired temperature range of 25 to 100 C. This paper presents a description of ongoing research at NASA-Langley on Pt/SnO2 catalyzed CO-O2 recombination. Included are studies with rare-isotope gases since rare-isotope CO2 is desirable as a laser gas for enhanced atmospheric transmission. Results presented include: (1) the effects of various catalyst pretreatment techniques on catalyst efficiency; (2) development of a technique, verified in a 30-hour test, to prevent isotopic scrambling when C(O-18) and (O-18)2 are reacted in the presence of a common-isotope Pt/Sn(O-16)2 catalyst; and (3) development of a mathematical model of a laser discharge prior to catalyst introduction.

  3. Sensitivity study on nitrogen Brayton cycle coupled with a small ultra-long cycle fast reactor

    International Nuclear Information System (INIS)

    Seo, Seok Bin; Seo, Han; Bang, In Cheol

    2014-01-01

    The main characteristics of UCFR are constant neutron flux and power density. They move their positions every moment at constant speed along with axial position of fuel rod for 60 years. Simultaneously with the development of the reactors, a new power conversion system has been considered. To solve existing issues of vigorous sodium-water reaction in SFR with steam power cycle, many researchers suggested a closed Brayton cycle as an alternative technique for SFR power conversion system. Many inactive gases are selected as a working fluid in Brayton power cycle, mainly supercritical CO 2 (S-CO 2 ). However, S-CO 2 still has potential for reaction with sodium. CO 2 -sodium reaction produces solid product, which has possibility to have an auto ignition reaction around 600 .deg. C. Thus, instead of S-CO 2 , CEA in France has developed nitrogen power cycle for ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration). In addition to inactive characteristic of nitrogen with sodium, its thermal and physical similarity with air enables to easily adopt to existing air Brayton cycle technology. In this study, for an optimized power conversion system for UCFR, a nitrogen Brayton cycle was analyzed in thermodynamic aspect. Based on subchannel analysis data of UCFR-100, a parametric study for thermal performance of nitrogen Brayton cycle was achieved. The system maximum pressure significantly affects to the overall efficiency of cycle, while other parameters show little effects. Little differences of the overall efficiencies for all cases between three stages (BOC, MOC, EOC) indicate that the power cycle of UCFR-100 maintains its performance during the operation

  4. 10 MW Supercritical CO2 Turbine Test

    Energy Technology Data Exchange (ETDEWEB)

    Turchi, Craig

    2014-01-29

    The Supercritical CO2 Turbine Test project was to demonstrate the inherent efficiencies of a supercritical carbon dioxide (s-CO2) power turbine and associated turbomachinery under conditions and at a scale relevant to commercial concentrating solar power (CSP) projects, thereby accelerating the commercial deployment of this new power generation technology. The project involved eight partnering organizations: NREL, Sandia National Laboratories, Echogen Power Systems, Abengoa Solar, University of Wisconsin at Madison, Electric Power Research Institute, Barber-Nichols, and the CSP Program of the U.S. Department of Energy. The multi-year project planned to design, fabricate, and validate an s-CO2 power turbine of nominally 10 MWe that is capable of operation at up to 700°C and operates in a dry-cooled test loop. The project plan consisted of three phases: (1) system design and modeling, (2) fabrication, and (3) testing. The major accomplishments of Phase 1 included: Design of a multistage, axial-flow, s-CO2 power turbine; Design modifications to an existing turbocompressor to provide s-CO2 flow for the test system; Updated equipment and installation costs for the turbomachinery and associated support infrastructure; Development of simulation tools for the test loop itself and for more efficient cycle designs that are of greater commercial interest; Simulation of s-CO2 power cycle integration into molten-nitrate-salt CSP systems indicating a cost benefit of up to 8% in levelized cost of energy; Identification of recuperator cost as a key economic parameter; Corrosion data for multiple alloys at temperatures up to 650ºC in high-pressure CO2 and recommendations for materials-of-construction; and Revised test plan and preliminary operating conditions based on the ongoing tests of related equipment. Phase 1 established that the cost of the facility needed to test the power turbine at its full power and temperature would exceed the planned funding for Phases 2 and 3. Late

  5. Cost and performance of fossil fuel power plants with CO2 capture and storage

    International Nuclear Information System (INIS)

    Rubin, Edward S.; Chen, Chao; Rao, Anand B.

    2007-01-01

    CO 2 capture and storage (CCS) is receiving considerable attention as a potential greenhouse gas (GHG) mitigation option for fossil fuel power plants. Cost and performance estimates for CCS are critical factors in energy and policy analysis. CCS cost studies necessarily employ a host of technical and economic assumptions that can dramatically affect results. Thus, particular studies often are of limited value to analysts, researchers, and industry personnel seeking results for alternative cases. In this paper, we use a generalized modeling tool to estimate and compare the emissions, efficiency, resource requirements and current costs of fossil fuel power plants with CCS on a systematic basis. This plant-level analysis explores a broader range of key assumptions than found in recent studies we reviewed for three major plant types: pulverized coal (PC) plants, natural gas combined cycle (NGCC) plants, and integrated gasification combined cycle (IGCC) systems using coal. In particular, we examine the effects of recent increases in capital costs and natural gas prices, as well as effects of differential plant utilization rates, IGCC financing and operating assumptions, variations in plant size, and differences in fuel quality, including bituminous, sub-bituminous and lignite coals. Our results show higher power plant and CCS costs than prior studies as a consequence of recent escalations in capital and operating costs. The broader range of cases also reveals differences not previously reported in the relative costs of PC, NGCC and IGCC plants with and without CCS. While CCS can significantly reduce power plant emissions of CO 2 (typically by 85-90%), the impacts of CCS energy requirements on plant-level resource requirements and multi-media environmental emissions also are found to be significant, with increases of approximately 15-30% for current CCS systems. To characterize such impacts, an alternative definition of the 'energy penalty' is proposed in lieu of the

  6. Solar Cycle Variations of SABER CO2 and MLS H2O in the Mesosphere and Lower Thermosphere Region

    Science.gov (United States)

    Salinas, C. C. J.; Chang, L. C.; Liang, M. C.; Qian, L.; Yue, J.; Russell, J. M., III; Mlynczak, M. G.

    2017-12-01

    This work aims to present the solar cycle variations of SABER CO2 and MLS H2O in the Mesosphere and Lower Thermosphere region. These observations are then compared to SD-WACCM outputs of CO2 and H2O in order to understand their physical mechanisms. After which, we attempt to model their solar cycle variations using the default TIME-GCM and the TIME-GCM with MERRA reanalysis as lower-boundary conditions. Comparing the outputs of the default TIME-GCM and TIME-GCM with MERRA will give us insight into the importance of solar forcing and lower atmospheric forcing on the solar cycle variations of CO2 and H2O. The solar cycle influence in the parameters are calculated by doing a multiple linear regression with the F10.7 index. The solar cycle of SABER CO2 is reliable above 1e-2 mb and below 1e-3 mb. Preliminary results from the observations show that SABER CO2 has a stronger negative anomaly due to the solar cycle over the winter hemisphere. MLS H2O is reliable until 1e-2. Preliminary results from the observations show that MLS H2O also has a stronger negative anomaly due to the solar cycle over the winter hemisphere. Both SD-WACCM and the default TIME-GCM reproduce these stronger anomalies over the winter hemisphere. An analysis of the tendency equations in SD-WACCM and default TIME-GCM then reveal that for CO2, the stronger winter anomaly may be attributed to stronger downward transport over the winter hemisphere. For H2O, an analysis of the tendency equations in SD-WACCM reveal that the stronger winter anomaly may be attributed to both stronger downward transport and stronger photochemical loss. On the other hand, in the default TIME-GCM, the stronger winter anomaly in H2O may only be attributed to stronger downward transport. For both models, the stronger downward transport is attributed to enhanced stratospheric polar winter jet during solar maximum. Future work will determine whether setting the lower boundary conditions of TIME-GCM with MERRA will improve the match

  7. Nuclear power and its role in limiting CO2 emissions

    International Nuclear Information System (INIS)

    Suparman

    2012-01-01

    The objective of this study is to analyze the proper role of nuclear power in the long term energy planning by comparing different type of scenarios in terms of CO2 emission reduction, based on the Business-as-Usual (BAU) scenario. For this purpose, a MESSAGE (Model of Energy Supply Systems and their General Environmental impacts) was used to develop energy planning as well as CO2 emission projection. A sensitivity analysis for CO2 reduction rates of 2.%, 3%, 4% and 5% have been done. From this sensitivity analysis, it can be concluded that nuclear will be a part of optimum solution under CO2 limitation of at least 3% from BAU condition. The more the environmental standards are tightened and enforced the more and the earlier nuclear power becomes part of the optimum generation mix. (author)

  8. Trend of CO2 emissions of the 30 largest power plants in Germany

    International Nuclear Information System (INIS)

    Hermann, Hauke

    2014-01-01

    The brochure on the trend of CO 2 emissions of the 30 largest power plants in Germany includes tables of the emissions of these power plants. The CO 2 emissions of these power plants in 2013 (25% of the total German greenhouse gas emissions) have increased by 5% compared to 2012. The total CO 2 emission sin Germany increased by 1.5%. The differences between brown coal and black coal fired power plants are discussed.

  9. Relative estimates of TCA cycle pool size from 14CO2 production profiles

    International Nuclear Information System (INIS)

    Kelleher, J.K.; Cesta, M.L.; Holleran, A.L.

    1986-01-01

    In metabolic and isotopic steady state, the rate of 14 CO 2 production by TCA cycle intermediates labeled at different positions is linear. However, before the system reaches isotopic steady state, the rate of 14 CO 2 production is non-linear. The x-intercept extrapolated from the linear phase indicates the turnover rate of all metabolic pools the tracer must pass through. By exposing identical systems to 14 C succinate labeled in different positions, the contribution of TCA cycle pools to the non-linear phase may be considered. Specifically, the extrapolated x-intercept for [2,3 14 C] succinate will be greater than the x-intercept for [1,4 14 C] succinate if the TCA cycle pools are a contributing factor to the non-linear phase. The authors have used this method to analyze pyruvate oxidation in AS 30D hepatoma cells. They found that the extrapolated x-intercepts for the two tracers were identical. This indicates that the non-linear phase resulted from equilibration of the tracer with pools prior to entering the TCA cycle, i.e. lactate. Using this technique, it may be possible to estimate the variations in TCA cycle pool sizes in vivo

  10. Supercritical CO2 test loop operation and first test results

    International Nuclear Information System (INIS)

    Wright, Steven A.; Pickard, Paul S.

    2009-01-01

    The DOE Office of Nuclear Energy is investigating advanced Brayton cycles for use with next generation nuclear power plants. The focus of this work is on the supercritical CO 2 Brayton cycle which has the potential for high efficiency, and for reduced capital costs due to very compact turbomachinery. Sandia has fabricated and is operating a supercritical CO 2 (S-CO 2 ) test loop to investigate the key technology issues associated with this cycle. This loop is part of a multi-year phased development program to develop a megawatt (MW) class closed S-CO 2 Brayton cycle to demonstrate the applicability of this cycle for DOE Gen-IV program. The current loop has been configured as both a compression loop and as simple heated but unrecuperated Brayton cycle. A second split-flow or re-compression Brayton cycle is currently under development that will use approximately 1 MW of heat to run the Brayton cycle. Early configurations of this split-flow Brayton cycle will be operational later this fiscal year. The key issues for this cycle include the fundamental issues of compressor fluid performance and system control near the critical point, but also the supporting technology issues of bearings, sealing technologies, and rotor windage losses which are also essential to achieving efficiency and cost objectives. These tests are providing the first measurements and information on these key supercritical CO 2 power conversion systems questions. Important data for all these issues has been obtained. This report presents the major results of the testing by showing and comparing the measured compressor performance map with the predicted performance. The compression loop uses a ∼50 kWe motor driven compressor to spin a 37 mm OD compressor at design speeds up to 75,000 rpm with a pressure ratio of 1.8 and a flow rate of 3.53 kg/s for a compressor inlet condition of 305.3 K and 7690 kPa. The most recent configuration of this loop has added a small turbine and 260 kW of heater power is

  11. Power cycling and ramp test in R-2 and Mihama Unit 2 for MHI PWR fuels

    International Nuclear Information System (INIS)

    Baba, T.; Takahashi, T.; Kubo, H.; Fujiwara, Y.; Kondo, Y.

    1983-01-01

    Up to the present time, Mitsubishi has manufactured approximately 3000 fuel assemblies for Japanese PWRs, of which performance in reactors is satisfactory under base load operation. For the forthcoming load following age in Japan, expected in mid eighties, Mitsubishi is performing various R and D programs, so that load following operation can be smoothly introduced with current good performance maintained. R and D programs consist of two phases. One is the verification and demonstration of power ramping and cycling capability of the current design fuels, and the other is the development of remedy fuels with more operational margin. This paper describes the recent results obtained for the former phase, especially for the following two programs: (1) Power cycling and ramp test in R-2; (2) Power ramp demonstration (PRD) in Mihama Unit 2 (PRD-1). PIE works for power cycling and ramp test rods have been almost completed. The second PRD will be performed early in 1983

  12. Possible applications of powerful pulsed CO2-Lasers in tokamak

    International Nuclear Information System (INIS)

    Nastoyashchii, A.F.; Morozov, I.N.; Hassanein, A.

    1998-01-01

    Applications of powerful pulsed CO 2 -lasers for injection of fuel tablets or creation of a protective screen from the vapor of light elements to protect against the destruction of plasma-facing components are discussed, and the corresponding laser parameters are determined. The possibility of using CO 2 -lasers in modelling the phenomena of powerful and energetic plasma fluxes interaction with a wall, as in the case of a plasma disruption, is considered. (author)

  13. The Martian hydrologic cycle - Effects of CO2 mass flux on global water distribution

    Science.gov (United States)

    James, P. B.

    1985-01-01

    The Martian CO2 cycle, which includes the seasonal condensation and subsequent sublimation of up to 30 percent of the planet's atmosphere, produces meridional winds due to the consequent mass flux of CO2. These winds currently display strong seasonal and hemispheric asymmetries due to the large asymmetries in the distribution of insolation on Mars. It is proposed that asymmetric meridional advection of water vapor on the planet due to these CO2 condensation winds is capable of explaining the observed dessication of Mars' south polar region at the current time. A simple model for water vapor transport is used to verify this hypothesis and to speculate on the effects of changes in orbital parameters on the seasonal water cycle.

  14. Reactivation properties of carbide slag as a CO{sub 2} sorbent during calcination/carbonation cycles

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yingjie; Sun, Rongyue; Liu, Hongling; Lu, Chunmei [Shandong Univ., Jinan (China). School of Energy and Power Engineering

    2013-07-01

    The carbide slag from polyvinyl chloride production as industry hazardous wastes was proposed as CO{sub 2} sorbent at high temperature in calcium looping cycle. The cyclic CO{sub 2} capture behavior and the microstructure characteristics of the carbide slag as one of the typical calcium-based industrial wastes during the multiple calcination/carbonation cycles. Also, the comparisons between the carbide slag and the natural limestone in cyclic CO{sub 2} capture behavior were made. XRD analysis demonstrates that the predominating constituent of the carbide slag is Ca(OH){sub 2}. The carbonation temperature ranging from 650 to 700 C is favourable to cyclic carbonation of the carbide slag. The cyclic carbonation conversions of the carbide slag is lower than that of the limestone before a certain time, but the situation is converse after that time in a thermogravimetric analyzer. The carbide slag has better cyclic CO{sub 2} capture capacity. The carbonation conversion of the carbide slag retains 0.28 after 100 calcination/carbonation cycles, while the two limestones achieve 0.08 and 0.14 respectively at the same reaction conditions in a dual fixed-bed reactor. The microstructure of the carbide slag by SEM reveals the reason why it possesses better CO{sub 2} capture capacity.

  15. High-performance cobalt carbonate hydroxide nano-dot/NiCo(CO3)(OH)2 electrode for asymmetric supercapacitors

    Science.gov (United States)

    Lee, Damin; Xia, Qi Xun; Yun, Je Moon; Kim, Kwang Ho

    2018-03-01

    Binder-free mesoporous NiCo(CO3)(OH)2 nanowire arrays were grown using a facile hydrothermal technique. The Co2(CO3)(OH)2 in NiCo(CO3)(OH)2 nanowire arrays was well-decorated as nano-dot scale (a few nanometer). In addition, increasing cobalt content in nickel compound matrix, NiCo(CO3)(OH)2 nanowire arrays were separately uniformly grown without agglomeration on Ni foam, providing a high specific surface area to help electrolyte access and ion transfer. The enticing composition and morphology of the NiCo(CO3)(OH)2 nanowire exhibit a superior specific capacity of 1288.2 mAh g-1 at a current density of 3 A g-1 and excellent cycling stability with the capacity retention of 80.7% after 10,000 cycles. Furthermore, an asymmetric supercapacitor composed of the NiCo(CO3)(OH)2 composite as a positive electrode and the graphene as a negative electrode presented a high energy density of 35.5 W h kg-1 at a power density of 2555.6 W kg-1 and satisfactory cycling stability with 71.3% capacity retention after 10,000 cycles. The great combination of the active nano-dot Co2(CO3)(OH)2 and the individually grown NiCo(CO3)(OH)2 nanowires made it a promising electrode material for asymmetric supercapacitors. A well-developed nanoarchitecture of the nano-dot Co2(CO3)(OH)2 decorated NiCo(CO3)(OH)2 composite could pave the way for an excellent electrode design for high-performance supercapacitors.

  16. Simulatd Nitrogen Cycling Response to Elevated CO2 in Pinus taeda and Mixed Dediduous Forests

    Science.gov (United States)

    D.W. Johnson

    1999-01-01

    Interactions between elevated CO2 and N cycling were explored with a nutrient cycling model (NuCM, Johnson et al. 1993, 1995) for a Pinus tuedu L. site at Duke University North Carolina, and a mixed deciduous site at Walker Branch, Tennessee. The simulations tested whether N limitation would prevent growth increases in response to elevated CO...

  17. Sodium fast reactors energy conversion systems. Na-CO2 interaction. Comparison with Na-water interaction of conventional water Rankine cycle

    International Nuclear Information System (INIS)

    Latge, Christian; Simon, Nicole

    2006-01-01

    The Sodium Fast Reactor is a very promising candidate for the development of Fast Neutron Reactors. It is well known owing to its wide development since the 1950's, throughout all countries involved in the development of nuclear power plants. The development of Sodium-cooled fast neutron reactors is possible due to its very attractive sodium, nuclear, physical and even some of its chemical properties. Nevertheless, the operational feedback has shown that the concept has several drawbacks: difficulties for In-Service Inspection and Repair operations due to the sodium opacity and possible detrimental effects of its reactivity with air and water when the heat conversion is performed with a conventional Rankine cycle. Moreover, the various design projects have shown some difficulties in enhancing its competitiveness with regards to existing NPPs without any new innovative options, i.e. the possibility of suppressing the intermediate circuits and/or the development of an optimized energy conversion system. The Supercritical CO 2 Brayton Cycle option for the energy conversion has been widely suggested because of its high thermodynamic efficiency (over 40%), its potential compactness of the Balance Of Plant equipment due to the small-sized turbo machinery system, and for its applicability to both Direct or Indirect Cycle (Na, PbBi, He) assuming the hypothesis that the Supercritical CO 2 -Na interaction has less serious potential consequences than sodium-water consequences in the conventional Rankine cycle. Within the framework of the SMFR (Small Modular Fast Reactor) project, developed jointly by Argonne National Laboratory (ANL-USA), the 'Commissariat a l'Energie Atomique' (CEA) and Japan Atomic Energy Agency (JAEA, formerly Japan Nuclear Cycle development), this option has been selected and investigated. This paper deals with the study of the interaction between Na and CO 2 , based on a literature review: the result of this study will allow the definition of R and D

  18. Numerical Comparison of NASA's Dual Brayton Power Generation System Performance Using CO2 or N2 as the Working Fluid

    Science.gov (United States)

    Ownens, Albert K.; Lavelle, Thomas M.; Hervol, David S.

    2010-01-01

    A Dual Brayton Power Conversion System (DBPCS) has been tested at the NASA Glenn Research Center using Nitrogen (N2) as the working fluid. This system uses two closed Brayton cycle systems that share a common heat source and working fluid but are otherwise independent. This system has been modeled using the Numerical Propulsion System Simulation (NPSS) environment. This paper presents the results of a numerical study that investigated system performance changes resulting when the working fluid is changed from gaseous (N2) to gaseous carbon dioxide (CO2).

  19. Performance of a Supercritical CO2 Bottoming Cycle for Aero Applications

    Directory of Open Access Journals (Sweden)

    Florian Jacob

    2017-03-01

    Full Text Available By 2050, the evolutionary approach to aero engine research may no longer provide meaningful returns on investment, whereas more radical approaches to improving thermal efficiency and reducing emissions might still prove cost effective. One such radical concept is the addition of a secondary power cycle that utilizes the otherwise largely wasted residual heat in the core engine’s exhaust gases. This could provide additional shaft power. Supercritical carbon dioxide closed-circuit power cycles are currently being investigated primarily for stationary power applications, but their high power density and efficiency, even for modest peak cycle temperatures, makes them credible bottoming cycle options for aero engine applications. Through individual geometric design and performance studies for each of the bottoming cycle’s major components, it was determined that a simple combined cycle aero engine could offer a 1.9% mission fuel burn benefit over a state-of-the-art geared turbofan for the year 2050. However, the even greater potential of more complex systems demands further investigation. For example, adding inter-turbine reheat (ITR to the combined cycle is predicted to significantly improve the fuel burn benefit.

  20. Coal-based synthetic natural gas (SNG): A solution to China’s energy security and CO2 reduction?

    International Nuclear Information System (INIS)

    Ding, Yanjun; Han, Weijian; Chai, Qinhu; Yang, Shuhong; Shen, Wei

    2013-01-01

    Considering natural gas (NG) to be the most promising low-carbon option for the energy industry, large state owned companies in China have established numerous coal-based synthetic natural gas (SNG) projects. The objective of this paper is to use a system approach to evaluate coal-derived SNG in terms of life-cycle energy efficiency and CO 2 emissions. This project examined main applications of the SNG and developed a model that can be used for evaluating energy efficiency and CO 2 emissions of various fuel pathway systems. The model development started with the GREET model, and added the SNG module and an end-use equipment module. The database was constructed with Chinese data. The analyses show when the SNG are used for cooking, power generation, steam production for heating and industry, life-cycle energies are 20–108% higher than all competitive pathways, with a similar rate of increase in life-cycle CO 2 emissions. When a compressed natural gas (CNG) car uses the SNG, life-cycle CO 2 emission will increase by 150–190% compared to the baseline gasoline car and by 140–210% compared to an electric car powered by electricity from coal-fired power plants. The life-cycle CO 2 emission of SNG-powered city bus will be 220–270% higher than that of traditional diesel city bus. The gap between SNG-powered buses and new hybrid diesel buses will be even larger—life-cycle CO 2 emission of the former being around 4 times of that of the latter. It is concluded that the SNG will not accomplish the tasks of both energy conservation and CO 2 reduction. - Highlights: ► We evaluated life-cycle energy efficiency and CO 2 emissions of coal-derived SNG. ► We used GREET model and added a coal-based SNG and an end-use modules. ► The database was constructed with Chinese domestic data. ► Life-cycle energies and CO 2 emissions of coal-based SNG are 20–100% higher. ► Coal-based SNG is not a solution to both energy conservation and CO 2 reduction

  1. Power stabilized CO2 gas transport laser

    International Nuclear Information System (INIS)

    Foster, J.D.; Kirk, R.F.; Moreno, F.E.; Ahmed, S.A.

    1975-01-01

    The output power of a high power (1 kW or more) CO 2 gas transport laser is stabilized by flowing the gas mixture over copper plated baffles in the gas channel during operation of the laser. Several other metals may be used instead of copper, for example, nickel, manganese, palladium, platinum, silver and gold. The presence of copper in the laser gas circuit stabilizes output power by what is believed to be a compensation of the chemical changes in the gas due to the cracking action of the electrical discharge which has the effect of diminishing the capactiy of the carbon dioxide gas mixture to maintain the rated power output of the laser. (U.S.)

  2. Preliminary study of S-CO{sub 2} cycle control logic for part load operation

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Yoonhan; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2016-05-15

    The benefits of S-CO{sub 2} cycle are relatively high efficiency under the mild turbine inlet temperature region, simple layout configuration and small foot-print. In addition, the safety of the SFR system can be inherently enhanced as the violent sodium-water reaction can be substituted with the mild sodium-CO{sub 2} reaction. 75MWe S-CO{sub 2} recompression cycle with radial type turbomachineries and PCHE was designed. Under various part load conditions (30-100% thermal load), off-design performance of the designed system was assessed, and different control logics were first tested. It was identified that the inventory control strategy is the most efficient logic for the part load operation. In the system operation, the compressor surge condition is seriously considered and controlled to avoid the system damage.

  3. Coal gasification integration with solid oxide fuel cell and chemical looping combustion for high-efficiency power generation with inherent CO2 capture

    International Nuclear Information System (INIS)

    Chen, Shiyi; Lior, Noam; Xiang, Wenguo

    2015-01-01

    Highlights: • A novel power system integrating coal gasification with SOFC and chemical looping combustion. • The plant net power efficiency reaches 49.8% with complete CO 2 separation. • Energy and exergy analysis of the entire plant is conducted. • Sensitivity analysis shows a nearly constant power output when SOFC temperature and pressure vary. • NiO oxygen carrier shows higher plant efficiency than using Fe 2 O 3 and CuO. - Abstract: Since solid oxide fuel cells (SOFC) produce electricity with high energy conversion efficiency, and chemical looping combustion (CLC) is a process for fuel conversion with inherent CO 2 separation, a novel combined cycle integrating coal gasification, solid oxide fuel cell, and chemical looping combustion was configured and analyzed. A thermodynamic analysis based on energy and exergy was performed to investigate the performance of the integrated system and its sensitivity to major operating parameters. The major findings include that (1) the plant net power efficiency reaches 49.8% with ∼100% CO 2 capture for SOFC at 900 °C, 15 bar, fuel utilization factor = 0.85, fuel reactor temperature = 900 °C and air reactor temperature = 950 °C, using NiO as the oxygen carrier in the CLC unit. (2) In this parameter neighborhood the fuel utilization factor, the SOFC temperature and SOFC pressure have small effects on the plant net power efficiency because changes in pressure and temperature that increase the power generation by the SOFC tend to decrease the power generation by the gas turbine and steam cycle, and v.v.; an advantage of this system characteristic is that it maintains a nearly constant power output even when the temperature and pressure vary. (3) The largest exergy loss is in the gasification process, followed by those in the CO 2 compression and the SOFC. (4) Compared with the CLC Fe 2 O 3 and CuO oxygen carriers, NiO results in higher plant net power efficiency. To the authors’ knowledge, this is the first

  4. CO2 cost pass-through and windfall profits in the power sector

    International Nuclear Information System (INIS)

    Sijm, Jos; Neuhoff, Karsten; Yihsu Chen

    2006-01-01

    In order to cover their CO 2 emissions, power companies receive most of the required EU ETS allowances for free. In line with economic theory, these companies pass on the costs of these allowances in the price of electricity. This article analyses the implications of the EU ETS for the power sector, notably the impact of free allocation of CO 2 emission allowances on the price of electricity and the profitability of power generation. As well as some theoretical reflections, the article presents empirical and model estimates of CO 2 cost pass-through for Germany and The Netherlands, indicating that pass-through rates vary between 60 and 100% of CO 2 costs, depending on the carbon intensity of the marginal production unit and various other market- or technology-specific factors. As a result, power companies realize substantial windfall profits, as indicated by the empirical and model estimates presented in the article. (Author)

  5. Flow Distribution Measurement Feasibility in Supercritical CO2

    Energy Technology Data Exchange (ETDEWEB)

    Lance, Blake [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-12-01

    Supercritical CO2 (sCO2) is a fluid of interest for advanced power cycles that can reach thermal to electric energy conversion efficiencies of 50% or higher. Of particular interest for fossil-fired natural gas is the Allam cycle that captures nearly all CO2 emissions and exports it as a fluid stream where it may be of value. The combustion process conditions are unlike any before realized with 90-95% CO2 concentration, temperatures around 1000°C, and pressures near 300 bar. This work outlines the experimental feasibility of flow measurements to acquire the first known data in pure sCO2 at similar but reduced temperature and pressure conditions.

  6. The role of policy instruments for promoting combined heat and power production with low CO2 emissions in district heating systems

    International Nuclear Information System (INIS)

    Marbe, A.; Harvey, S.

    2005-01-01

    Policy instruments clearly influence the choice of production technologies and fuels in large energy systems, including district heating networks. Current Swedish policy instruments aim at promoting the use of biofuel in district heating systems, and at promoting electric power generation from renewable energy sources. However, there is increasing pressure to harmonize energy policy instruments within the EU. In addition, natural gas based combined cycle technology has emerged as the technology of choice in the power generation sector in the EU. This study aims at exploring the role of policy instruments for promoting the use of low CO 2 emissions fuels in high performance combined heat and power systems in the district heating sector. The paper presents the results of a case study for a Swedish district heating network where new large size natural gas combined cycle (NGCC) combined heat and power (CHP) is being built. Given the aim of current Swedish energy policy, it is assumed that it could be of interest in the future to integrate a biofuel gasifier to the CHP plant and co-fire the gasified biofuel in the gas turbine unit, thereby reducing usage of fossil fuel. The goals of the study are to evaluate which policy instruments promote construction of the planned NGCC CHP unit, the technical performance of an integrated biofuelled pressurized gasifier with or without dryer on plant site, and which combination of policy instruments promote integration of a biofuel gasifier to the planned CHP unit. The power plant simulation program GateCycle was used for plant performance evaluation. The results show that current Swedish energy policy instruments favour investing in the NGCC CHP unit. The corresponding cost of electricity (COE) from the NGCC CHP unit is estimated at 253 SEK MWh -1 , which is lower than the reference power price of 284 SEK MWh -1 . Investing in the NGCC CHP unit is also shown to be attractive if a CO 2 trading system is implemented. If the value of

  7. Studies on CO2 removal and reduction. CO2 taisaku kenkyu no genjo

    Energy Technology Data Exchange (ETDEWEB)

    Shindo, Y [National Institute of Materials and Chemical Research, Tsukuba (Japan)

    1993-02-01

    This paper summarizes study trends mainly in CO2 fixing processes. Underground CO2 storage is a most promising method because it can fix a huge amount of CO2 and has low effects on ecological systems. Storing CO2 in ocean includes such methods as storing it in deep oceans; storing it in deep ocean beds; dissolving it into sea water; neutralizing it with calcium carbonates; and precipitating it as dry ice. Japan, disposing CO2 in these ways, may create international problems. Separation of CO2 may use a chemical absorption process as a superior method. Other processes discussed include a physical adsorption method and a membrane separation method. A useful method for CO2 fixation using marine organisms is fixation using coral reefs. This process will require an overall study including circulation of phosphorus and nitrogen. Marine organisms may include planktons and algae. CO2 fixation using land plants may be able to fix one trillion and 8 hundred billion tons of CO2 as converted to carbon. This process would require forest protection, prevention of desertification, and tree planting. Discussions are being given also on improving power generation cycles, recovering CO2 from automotive exhausts, and backfilling carbons into ground by means of photosynthesis. 23 refs., 7 figs., 1 tab.

  8. On q-power cycles in cubic graphs

    DEFF Research Database (Denmark)

    Bensmail, Julien

    2017-01-01

    In the context of a conjecture of Erdos and Gyárfás, we consider, for any q ≥ 2, the existence of q-power cycles (i.e. with length a power of q) in cubic graphs. We exhibit constructions showing that, for every q ≥ 3, there exist arbitrarily large cubic graphs with no q-power cycles. Concerning...... the remaining case q = 2 (which corresponds to the conjecture of Erdos and Gyárfás), we show that there exist arbitrarily large cubic graphs whose only 2-power cycles have length 4 only, or 8 only....

  9. Techno-economic study of CO2 capture from an existing coal-fired power plant: MEA scrubbing vs. O2/CO2 recycle combustion

    International Nuclear Information System (INIS)

    Singh, D.; Croiset, E.; Douglas, P.L.; Douglas, M.A.

    2003-01-01

    The existing fleet of modern pulverised coal fired power plants represents an opportunity to achieve significant reductions in greenhouse gas emissions in the coming years providing that efficient and economical CO 2 capture technologies are available for retrofit. One option is to separate CO 2 from the products of combustion using conventional approaches such as amine scrubbing. An emerging alternative, commonly known as O 2 /CO 2 recycle combustion, involves burning the coal with oxygen in an atmosphere of recycled flue gas. Both approaches can be retrofitted to existing units, however they consume significant amounts of energy to capture, purify and compress the CO 2 for subsequent sequestration. This paper presents a techno-economic comparison of the performance of the two approaches. The comparison was developed using the commercial process simulation packages, Hysys and Aspen Plus. The results show that both processes are expensive options to capture CO 2 from coal power plants, however O 2 /CO 2 appears to be a more attractive retrofit than MEA scrubbing. The CO 2 capture cost for the MEA case is USD 53/ton of CO 2 avoided, which translates into 3.3 cents/kW h. For the O 2 /CO 2 case the CO 2 capture cost is lower at USD 35/ton of CO 2 avoided, which translates into 2.4 cents/kW h. These capture costs represent an approximate increase of 20-30% in current electricity prices

  10. Plasma-assisted CO2 conversion: optimizing performance via microwave power modulation

    Science.gov (United States)

    Britun, Nikolay; Silva, Tiago; Chen, Guoxing; Godfroid, Thomas; van der Mullen, Joost; Snyders, Rony

    2018-04-01

    Significant improvement in the energy efficiency of plasma-assisted CO2 conversion is achieved with applied power modulation in a surfaguide microwave discharge. The obtained values of CO2 conversion and energy efficiency are, respectively, 0.23 and 0.33 for a 0.95 CO2  +  0.05 N2 gas mixture. Analysis of the energy relaxation mechanisms shows that power modulation can potentially affect the vibrational-translational energy exchange in plasma. In our case, however, this mechanism does not play a major role, likely due to the low degree of plasma non-equilibrium in the considered pressure range. Instead, the gas residence time in the discharge active zone together with plasma pulse duration are found to be the main factors affecting the CO2 conversion efficiency at low plasma pulse repetition rates. This effect is confirmed experimentally by the in situ time-resolved two-photon absorption laser-induced fluorescence measurements of CO molecular density produced in the discharge as a result of CO2 decomposition.

  11. Life cycle assessment of hydrogen and power production by supercritical water reforming of glycerol

    International Nuclear Information System (INIS)

    Galera, S.; Gutiérrez Ortiz, F.J.

    2015-01-01

    Highlights: • The environmental performance of the supercritical water reforming (SCWR) of glycerol was assessed. • Biogenic CO 2 emissions allowed quantifying a realistic GHG inventory of 3.8 kg CO 2 -eq/kg H 2 . • The environmental profile of SCWR process was compared to those of other technologies. • A good environmental performance of H 2 and power production by SCWR of glycerol was obtained. - Abstract: The environmental performance of hydrogen and electricity production by supercritical water reforming (SCWR) of glycerol was evaluated following a Life Cycle Assessment (LCA) approach. The heat-integrated process was designed to be energy self-sufficient. Mass and energy balances needed for the study were performed using Aspen Plus 8.4, and the environmental assessment was carried out through SimaPro 8.0. CML 2000 was selected as the life cycle impact assessment method, considering as impact categories the global warming, ozone layer depletion, abiotic depletion, photochemical oxidant formation, eutrophication, acidification, and cumulative energy demand. A distinction between biogenic and fossil CO 2 emissions was done to quantify a more realistic GHG inventory of 3.77 kg CO 2 -eq per kg H 2 produced. Additionally, the environmental profile of SCWR process was compared to other H 2 production technologies such as steam methane reforming, carbon gasification, water electrolysis and dark fermentation among others. This way, it is shown that SCWR of glycerol allows reducing greenhouse gas emissions and obtaining a favorable positive life cycle energy balance, achieving a good environmental performance of H 2 and power production by SCWR of glycerol

  12. System Design of a Supercritical CO_2 cooled Micro Modular Reactor

    International Nuclear Information System (INIS)

    Kim, Seong Gu; Cho, Seongkuk; Yu, Hwanyeal; Kim, Yonghee; Jeong, Yong Hoon; Lee, Jeong Ik

    2014-01-01

    Small modular reactor (SMR) systems that have advantages of little initial capital cost and small restriction on construction site are being developed by many research organizations around the world. Existing SMR concepts have the same objective: to achieve compact size and a long life core. Most of small modular reactors have much smaller size than the large nuclear power plant. However, existing SMR concepts are not fully modularized. This paper suggests a complete modular reactor with an innovative concept for reactor cooling by using a supercritical carbon dioxide. The authors propose the supercritical CO_2 Brayton cycle (S-CO_2 cycle) as a power conversion system to achieve small volume of power conversion unit (PCU) and to contain the reactor core and PCU in one vessel. A conceptual design of the proposed small modular reactor was developed, which is named as KAIST Micro Modular Reactor (MMR). The supercritical CO_2 Brayton cycle for the S-CO_2 cooled reactor core was optimized and the size of turbomachinery and heat exchanger were estimated preliminary. The nuclear fuel composed with UN was proposed and the core lifetime was obtained from a burnup versus reactivity calculation. Furthermore, a system layout with fully passive safety systems for both normal operation and emergency operation was proposed. (author)

  13. Life cycle assessment of a biomass gasification combined-cycle power system

    Energy Technology Data Exchange (ETDEWEB)

    Mann, M.K.; Spath, P.L.

    1997-12-01

    The potential environmental benefits from biomass power are numerous. However, biomass power may also have some negative effects on the environment. Although the environmental benefits and drawbacks of biomass power have been debated for some time, the total significance has not been assessed. This study serves to answer some of the questions most often raised in regard to biomass power: What are the net CO{sub 2} emissions? What is the energy balance of the integrated system? Which substances are emitted at the highest rates? What parts of the system are responsible for these emissions? To provide answers to these questions, a life cycle assessment (LCA) of a hypothetical biomass power plant located in the Midwest United States was performed. LCA is an analytical tool for quantifying the emissions, resource consumption, and energy use, collectively known as environmental stressors, that are associated with converting a raw material to a final product. Performed in conjunction with a technoeconomic feasibility study, the total economic and environmental benefits and drawbacks of a process can be quantified. This study complements a technoeconomic analysis of the same process, reported in Craig and Mann (1996) and updated here. The process studied is based on the concept of power Generation in a biomass integrated gasification combined cycle (BIGCC) plant. Broadly speaking, the overall system consists of biomass production, its transportation to the power plant, electricity generation, and any upstream processes required for system operation. The biomass is assumed to be supplied to the plant as wood chips from a biomass plantation, which would produce energy crops in a manner similar to the way food and fiber crops are produced today. Transportation of the biomass and other materials is by both rail and truck. The IGCC plant is sized at 113 MW, and integrates an indirectly-heated gasifier with an industrial gas turbine and steam cycle. 63 refs., 34 figs., 32 tabs.

  14. Life cycle assessment of a biomass gasification combined-cycle power system

    Energy Technology Data Exchange (ETDEWEB)

    Mann, M.K.; Spath, P.L.

    1997-12-01

    The potential environmental benefits from biomass power are numerous. However, biomass power may also have some negative effects on the environment. Although the environmental benefits and drawbacks of biomass power have been debated for some time, the total significance has not been assessed. This study serves to answer some of the questions most often raised in regard to biomass power: What are the net CO{sub 2} emissions? What is the energy balance of the integrated system? Which substances are emitted at the highest rates? What parts of the system are responsible for these emissions? To provide answers to these questions, a life cycle assessment (LCA) of a hypothetical biomass power plant located in the Midwest United States was performed. LCA is an analytical tool for quantifying the emissions, resource consumption, and energy use, collectively known as environmental stressors, that are associated with converting a raw material to a final product. Performed in conjunction with a t echnoeconomic feasibility study, the total economic and environmental benefits and drawbacks of a process can be quantified. This study complements a technoeconomic analysis of the same process, reported in Craig and Mann (1996) and updated here. The process studied is based on the concept of power Generation in a biomass integrated gasification combined cycle (BIGCC) plant. Broadly speaking, the overall system consists of biomass production, its transportation to the power plant, electricity generation, and any upstream processes required for system operation. The biomass is assumed to be supplied to the plant as wood chips from a biomass plantation, which would produce energy crops in a manner similar to the way food and fiber crops are produced today. Transportation of the biomass and other materials is by both rail and truck. The IGCC plant is sized at 113 MW, and integrates an indirectly-heated gasifier with an industrial gas turbine and steam cycle. 63 refs., 34 figs., 32 tabs.

  15. High power CO2 lasers and their applications in nuclear industry

    International Nuclear Information System (INIS)

    Nath, A.K.

    2002-01-01

    Carbon dioxide laser is one of the most popular lasers in industry for material processing applications. It has very high power capability and high efficiency, can be operated in continuous wave (CW), modulated and pulsed modes, and has relatively low cost. Due to these characteristics high power CO 2 lasers are being used worldwide in different industries for a wide variety of materials processing operations. In nuclear industry, CO 2 laser has made its way in many applications. Some of the tasks performed by multikilowatt CO 2 laser are cutting operations necessary to remove unprocessible hardware from reactor fuel assemblies, sealing/fixing/removing radioactive contaminations onto/from concrete surfaces and surface modification of engineering components for improved surface mechanical and metallurgical characteristics. We have developed various models of CW CO 2 lasers of power up to 12 kW and a high repetitive rate TEA (Transversely Excited Atmospheric pressure) CO 2 laser of 500 W average power operating at 500 Hz repetition rates. We have carried many materials processing applications of direct relevance to DAE. Recent work includes laser welding of end plug PFBR fuel tubes, martensitic stainless steel and titanium alloy, surface cladding of turbine blades made of Ni-super alloy with stellite 694, fabrication on graded material of stainless steel and stellite, and laser scabbling, drilling and cutting of concrete which have potential application in decontamination and decommissioning of nuclear facilities. A brief overview of these indigenous developments will be presented. (author)

  16. Supercritical CO2 Brayton cycle compression and control near the critical point

    International Nuclear Information System (INIS)

    Wright, S. A.; Fuller, R.; Noall, J.; Radel, R.; Vernon, M. E.; Pickard, P. S.

    2008-01-01

    . The current test plan will vary the inlet temperature from 290 K to 318 K, while the inlet pressure will be varied from 5-9.2 MPa. Over this range of temperature and pressure the compressor inlet conditions will vary from vapor conditions with an inlet density of 150 kg/m 3 to liquid conditions (at 800 kg/m 3). At the design point the S-CO 2 has a density of 650 kg/m 3 . These fluid densities are very high, which leads to Brayton cycles with very high power density and hence compact hardware. The report presents the results of analysis of two models that predict the flow characteristics of the supercritical compressor. One model is very simple and consists simply of a mean-line flow analysis for the compressor, while the other model relies on using similarity methods and analysis with existing compressor flow codes. Both methods use the NIST equation of state models for the CO 2 . The later method has the advantage of using existing codes with their existing loss models and can be used to predict compressor efficiency. The mean-line flow analysis method needs further work to fully implement the loss models so that the efficiency can be accurately predicted. These analytical results of the models will be compared with the available first test data. (authors)

  17. Cycling-induced degradation of LiCoO{sub 2} thin-film cathodes at elevated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Van Sluytman, J.S.; Alamgir, F.M.; Greenbaum, S.G. [Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, NY 10021 (United States); West, W.C.; Whitacre, J.F. [Electrochemical Technologies Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2006-04-01

    The cycle life of LiCoO{sub 2}-based all solid-state thin-film cells has been studied at room temperature, and at elevated temperatures of 50, 100, and 150{sup o}C. X-ray diffraction, as well as Raman analysis, has been used to complement the electrochemical data in examining structural and chemical changes. XRD and Raman spectroscopy data indicate that elevated temperature soaks of the thin-film batteries in the quiescent state causes no discernible changes in the LiCoO{sub 2} cathode layer. However, when the thin-film batteries are cycled at elevated temperatures, decreases in average grain size of the LiCoO{sub 2} film occur with dramatic concomitant charge and discharge capacity loss. (author)

  18. Energy Balance of Nuclear Power Generation. Life Cycle Analyses of Nuclear Power

    International Nuclear Information System (INIS)

    Wallner, A.; Wenisch, A.; Baumann, M.; Renner, S.

    2011-01-01

    The accident at the Japanese nuclear power plant Fukushima in March 2011 triggered a debate about phasing out nuclear energy and the safety of nuclear power plants. Several states are preparing to end nuclear power generation. At the same time the operational life time of many nuclear power plants is reaching its end. Governments and utilities now need to take a decision to replace old nuclear power plants or to use other energy sources. In particular the requirement of reducing greenhouse gas emissions (GHG) is used as an argument for a higher share of nuclear energy. To assess the contribution of nuclear power to climate protection, the complete life cycle needs to be taken into account. Some process steps are connected to high CO2 emissions due to the energy used. While the processes before and after conventional fossil-fuel power stations can contribute up to 25% of direct GHG emission, it is up to 90 % for nuclear power (Weisser 2007). This report aims to produce information about the energy balance of nuclear energy production during its life cycle. The following key issues were examined: How will the forecasted decreasing uranium ore grades influence energy intensity and greenhouse emissions and from which ore grade on will no energy be gained anymore? In which range can nuclear energy deliver excess energy and how high are greenhouse gas emissions? Which factors including ore grade have the strongest impact on excess energy? (author)

  19. Research on the Development of the Supercritical CO{sub 2} Dual Brayton Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Baik, Young-Jin; Na, Sun Ik; Cho, Junhyun; Shin, Hyung-Ki; Lee, Gilbong [Korea Institute of Energy Research (KIER), Daejeon (Korea, Republic of)

    2016-10-15

    Because of the growing interest in supercritical carbon dioxide power cycle technology owing to its potential enhancement in compactness and efficiency, supercritical carbon dioxide cycles have been studied in the fields of nuclear power, concentrated solar power (CSP), and fossil fuel power generation. This study introduces the current status of the research project on the supercritical carbon dioxide power cycle by Korea Institute of Energy Research (KIER). During the first phase of the project, the un-recuperated supercritical Brayton cycle test loop was built and tested. In phase two, researchers are designing and building a supercritical carbon dioxide dual Brayton cycle, which utilizes two turbines and two recuperators. Under the simulation condition considered in this study, it was confirmed that the design parameter has an optimal value for maximizing the net power in the supercritical carbon dioxide dual cycle.

  20. Modeling and simulation of syngas purification and power generation in integrated gasification combined cycle (IGCS)

    Energy Technology Data Exchange (ETDEWEB)

    Mehmood, N; Zaman, Z U; Mehran, M T [National Development, Islamabad (Pakistan)

    2011-07-01

    Integrated Gasification Combined Cycle (IGCC) is one of the most promising technologies for power generation; The environmental benefits and the higher energy conversion efficiency distinguish it from traditional coal generation technologies. This work presents a structured and validated conceptual model of purification of coal gas produced during the Underground Coal Gasification (UCG) of coal containing high sulfur contents. Gas cleaning operations for CO/sub 2/, H/sub 2/S and moisture removal have been modeled in steady and dynamic state. The power generation from combined cycle is also modeled. The model has been developed using Aspen HYSYS and Aspen Plus simulation software. Predicted results of clean gas composition and generated power present a good agreement with industrial data and efficiency parameters. This study is aimed at obtaining optimal assessment of an integrated gasification combined cycle (IGCC) power plant configurations. (author)

  1. Modeling and simulation of syngas purification and power generation in integrated gasification combined cycle (IGCS)

    International Nuclear Information System (INIS)

    Mehmood, N.; Zaman, Z.U.; Mehran, M.T.

    2011-01-01

    Integrated Gasification Combined Cycle (IGCC) is one of the most promising technologies for power generation; The environmental benefits and the higher energy conversion efficiency distinguish it from traditional coal generation technologies. This work presents a structured and validated conceptual model of purification of coal gas produced during the Underground Coal Gasification (UCG) of coal containing high sulfur contents. Gas cleaning operations for CO/sub 2/, H/sub 2/S and moisture removal have been modeled in steady and dynamic state. The power generation from combined cycle is also modeled. The model has been developed using Aspen HYSYS and Aspen Plus simulation software. Predicted results of clean gas composition and generated power present a good agreement with industrial data and efficiency parameters. This study is aimed at obtaining optimal assessment of an integrated gasification combined cycle (IGCC) power plant configurations. (author)

  2. Material Processing with High Power CO2-Lasers

    Science.gov (United States)

    Bakowsky, Lothar

    1986-10-01

    After a period of research and development lasertechnique now is regarded as an important instrument for flexible, economic and fully automatic manufacturing. Especially cutting of flat metal sheets with high power C02-lasers and CNC controlled two or three axes handling systems is a wide spread. application. Three dimensional laser cutting, laser-welding and -heat treatment are just at the be ginning of industrial use in production lines. The main. advantages of laser technology. are - high. accuracy - high, processing velocity - law thermal distortion. - no tool abrasion. The market for laser material processing systems had 1985 a volume of 300 Mio S with growth rates between, 20 % and 30 %. The topic of this lecture are hiTrh. power CO2-lasers. Besides this systems two others are used as machining tools, Nd-YAG- and Eximer lasers. All applications of high. power CO2-lasers to industrial material processing show that high processing velocity and quality are only guaranteed in case of a stable intensity. profile on the workpiece. This is only achieved by laser systems without any power and mode fluctuations and by handling systems of high accuracy. Two applications in the automotive industry are described, below as examples for laser cutting and laser welding of special cylindrical motor parts.

  3. AMERICAN ELECTRIC POWER'S CONESVILLE POWER PLANT UNIT NO.5 CO2 CAPTURE RETROFIT STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Carl R. Bozzuto; Nsakala ya Nsakala; Gregory N. Liljedahl; Mark Palkes; John L. Marion

    2001-06-30

    ALSTOM Power Inc.'s Power Plant Laboratories (ALSTOM) has teamed with American Electric Power (AEP), ABB Lummus Global Inc. (ABB), the US Department of Energy National Energy Technology Laboratory (DOE NETL), and the Ohio Coal Development Office (OCDO) to conduct a comprehensive study evaluating the technical feasibility and economics of alternate CO{sub 2} capture and sequestration technologies applied to an existing US coal-fired electric generation power plant. The motivation for this study was to provide input to potential US electric utility actions concerning GHG emissions reduction. If the US decides to reduce CO{sub 2} emissions, action would need to be taken to address existing power plants. Although fuel switching from coal to natural gas may be one scenario, it will not necessarily be a sufficient measure and some form of CO{sub 2} capture for use or disposal may also be required. The output of this CO{sub 2} capture study will enhance the public's understanding of control options and influence decisions and actions by government, regulators, and power plant owners in considering the costs of reducing greenhouse gas CO{sub 2} emissions. The total work breakdown structure is encompassed within three major reports, namely: (1) Literature Survey, (2) AEP's Conesville Unit No.5 Retrofit Study, and (3) Bench-Scale Testing and CFD Evaluation. The report on the literature survey results was issued earlier by Bozzuto, et al. (2000). Reports entitled ''AEP's Conesville Unit No.5 Retrofit Study'' and ''Bench-Scale Testing and CFD Evaluation'' are provided as companion volumes, denoted Volumes I and II, respectively, of the final report. The work performed, results obtained, and conclusions and recommendations derived therefrom are summarized.

  4. Possible applications of powerful pulsed CO2-lasers in tokamak reactors

    International Nuclear Information System (INIS)

    Nastoyashchii, A.F.; Morozov, I.N.; Hassanein, A.

    1998-01-01

    Applications of powerful pulsed CO 2 -lasers for injection of fuel tablets or creation of a protective screen from the vapor of light elements to protect against the destruction of plasma-facing components are discussed, and the corresponding laser parameters are determined. The possibility of using CO 2 -lasers in modeling the phenomena of powerful and energetic plasma fluxes interaction with a wall, as in the case of a plasma disruption, is considered

  5. State of the Carbon Cycle - Consequences of Rising Atmospheric CO2

    Science.gov (United States)

    Moore, D. J.; Cooley, S. R.; Alin, S. R.; Brown, M. E.; Butman, D. E.; French, N. H. F.; Johnson, Z. I.; Keppel-Aleks, G.; Lohrenz, S. E.; Ocko, I.; Shadwick, E. H.; Sutton, A. J.; Potter, C. S.; Yu, R. M. S.

    2016-12-01

    The rise of atmospheric CO2, largely attributable to human activity through fossil fuel emissions and land-use change, has been dampened by carbon uptake by the ocean and terrestrial biosphere. We outline the consequences of this carbon uptake as direct and indirect effects on terrestrial and oceanic systems and processes for different regions of North America and the globe. We assess the capacity of these systems to continue to act as carbon sinks. Rising CO2 has decreased seawater pH; this process of ocean acidification has impacted some marine species and altered fundamental ecosystem processes with further effects likely. In terrestrial ecosystems, increased atmospheric CO2 causes enhanced photosynthesis, net primary production, and increased water-use efficiency. Rising CO2 may change vegetation composition and carbon storage, and widespread increases in water use efficiency likely influence terrestrial hydrology and biogeochemical cycling. Consequences for human populations include changes to ecosystem services including cultural activities surrounding land use, agricultural or harvesting practices. Commercial fish stocks have been impacted and crop production yields have been changed as a result of rising CO2. Ocean and terrestrial effects are contingent on, and feedback to, global climate change. Warming and modified precipitation regimes impact a variety of ecosystem processes, and the combination of climate change and rising CO2 contributes considerable uncertainty to forecasting carbon sink capacity in the ocean and on land. Disturbance regime (fire and insects) are modified with increased temperatures. Fire frequency and intensity increase, and insect lifecycles are disrupted as temperatures move out of historical norms. Changes in disturbance patterns modulate the effects of rising CO2 depending on ecosystem type, disturbance frequency, and magnitude of events. We discuss management strategies designed to limit the rise of atmospheric CO2 and reduce

  6. State of the Carbon Cycle - Consequences of Rising Atmospheric CO2

    Science.gov (United States)

    Moore, David J.; Cooley, Sarah R.; Alin, Simone R.; Brown, Molly; Butman, David E.; French, Nancy H. F.; Johnson, Zackary I.; Keppel-Aleks; Lohrenz, Steven E.; Ocko, Ilissa; hide

    2016-01-01

    The rise of atmospheric CO2, largely attributable to human activity through fossil fuel emissions and land-use change, has been dampened by carbon uptake by the ocean and terrestrial biosphere. We outline the consequences of this carbon uptake as direct and indirect effects on terrestrial and oceanic systems and processes for different regions of North America and the globe. We assess the capacity of these systems to continue to act as carbon sinks. Rising CO2 has decreased seawater pH; this process of ocean acidification has impacted some marine species and altered fundamental ecosystem processes with further effects likely. In terrestrial ecosystems, increased atmospheric CO2 causes enhanced photosynthesis, net primary production, and increased water-use efficiency. Rising CO2 may change vegetation composition and carbon storage, and widespread increases in water use efficiency likely influence terrestrial hydrology and biogeochemical cycling. Consequences for human populations include changes to ecosystem services including cultural activities surrounding land use, agricultural or harvesting practices. Commercial fish stocks have been impacted and crop production yields have been changed as a result of rising CO2. Ocean and terrestrial effects are contingent on, and feedback to, global climate change. Warming and modified precipitation regimes impact a variety of ecosystem processes, and the combination of climate change and rising CO2 contributes considerable uncertainty to forecasting carbon sink capacity in the ocean and on land. Disturbance regime (fire and insects) are modified with increased temperatures. Fire frequency and intensity increase, and insect lifecycles are disrupted as temperatures move out of historical norms. Changes in disturbance patterns modulate the effects of rising CO2 depending on ecosystem type, disturbance frequency, and magnitude of events. We discuss management strategies designed to limit the rise of atmospheric CO2 and reduce

  7. Improvement of CaO-based sorbent performance for CO{sub 2} looping cycles

    Energy Technology Data Exchange (ETDEWEB)

    Vasilije Manovic; Edward J. Anthony [CANMET Energy Technology Centre-Ottawa, Ottawa, ON (Canada)

    2009-07-01

    This paper presents research on CO{sub 2} capture by lime-based looping cycles. This is a new and promising technology that may help in mitigation of global warming and climate change caused primarily by the use of fossil fuels. The intensity of the anticipated changes urgently requires solutions such as the developing technologies for CO{sub 2} capture, especially those based on CaO looping cycles. This technology is at the pilot plant demonstration stage and there are still significant challenges that require solutions. The technology is based on a dual fluidized bed reactor which contains a carbonator - a unit for CO{sub 2} capture, and a calciner - a unit for CaO regeneration. The major technology components are well known from other technologies and easily applicable. However, even though CaO is a very good candidate as a solid CO{sub 2} carrier, its performance in a practical system still has significant limitations. Thus, research on CaO performance is critical and this paper discusses some of the more important problems and potential solutions that are being examined at CETC-O. To date, the most promising methods were reactivation of spent sorbent by steam, thermal pretreatment of sorbent, and doping, most likely with Al{sub 2}O{sub 3}. The combination of these methods, including pelletization, should provide us with enhanced sorbent performance. 75 refs., 19 figs.

  8. Improvement of performance operation and cycle efficiency of Al Anbar combined power plant

    International Nuclear Information System (INIS)

    Jabbar, Mohammed Q.

    2014-01-01

    The present work will be focusing on available solution which can serve to increase total efficiency of Al Anbar combined cycle power plant - CCPP, and thus to improve the operation performance as much as possible in order to decrease hydrocarbon, CO2, NOx emissions to environment.The simulation and calculations were performed by program software cycle-tempo software. The results were compared with basic design of Alanbar power plant after making modernization with solar tower receiver system-STRS, which represented a heat source in preheat process for a compressor air. Key Words: CCPP, STRS, Solar potential energy, fuel consumption, hydrocarbon emission

  9. Thermodynamics analysis of a modified dual-evaporator CO2 transcritical refrigeration cycle with two-stage ejector

    International Nuclear Information System (INIS)

    Bai, Tao; Yan, Gang; Yu, Jianlin

    2015-01-01

    In this paper, a modified dual-evaporator CO 2 transcritical refrigeration cycle with two-stage ejector (MDRC) is proposed. In MDRC, the two-stage ejector are employed to recover the expansion work from cycle throttling processes and enhance the system performance and obtain dual-temperature refrigeration simultaneously. The effects of some key parameters on the thermodynamic performance of the modified cycle are theoretically investigated based on energetic and exergetic analyses. The simulation results for the modified cycle show that two-stage ejector exhibits more effective system performance improvement than the single ejector in CO 2 dual-temperature refrigeration cycle, and the improvements of the maximum system COP (coefficient of performance) and system exergy efficiency could reach 37.61% and 31.9% over those of the conventional dual-evaporator cycle under the given operating conditions. The exergetic analysis for each component at optimum discharge pressure indicates that the gas cooler, compressor, two-stage ejector and expansion valves contribute main portion to the total system exergy destruction, and the exergy destruction caused by the two-stage ejector could amount to 16.91% of the exergy input. The performance characteristics of the proposed cycle show its promise in dual-evaporator refrigeration system. - Highlights: • Two-stage ejector is used in dual-evaporator CO 2 transcritical refrigeration cycle. • Energetic and exergetic methods are carried out to analyze the system performance. • The modified cycle could obtain dual-temperature refrigeration simultaneously. • Two-stage ejector could effectively improve system COP and exergy efficiency

  10. An exergoeconomic assessment of waste heat recovery from a Gas Turbine-Modular Helium Reactor using two transcritical CO_2 cycles

    International Nuclear Information System (INIS)

    Wang, Xurong; Dai, Yiping

    2016-01-01

    Highlights: • A Gas Turbine-Modular Helium Reactor is coupled with two transcritical CO_2 cycles. • Exergoeconomic analysis and optimization of the combined cycle was performed. • The energy efficiency of the cogeneration system was enhanced by 7.92% at 850 °C. • The overall exergoeconomic factor of the system could up to 55.2%. - Abstract: A comprehensive study is performed on an energy conversion system which combines a gas turbine-modular helium reactor (GT-MHR) and two transcritical CO_2 cycles (tCO_2). The aim of this study is to assess the energy, exergy and economic behavior of the proposed system, considering five indicators: the energy efficiency, the exergy efficiency, the total exergy destruction cost rate, the overall exergoeconomic factor and the total cost rate. A parametric study is also conducted to evaluate the influence of key decision variables on the GT-MHR/tCO_2 performance. Finally, the combined cycle is optimized to minimize the total cost rate. The results show that the energy efficiency of GT-MHR/tCO_2 cycle is 7.92% higher than that of the simple GT-MHR cycle at 850 °C. The largest exergy destruction rate takes place in the reactor, and after that in the helium turbine and the recuperator. The components in tCO_2 cycles have less exergy destruction. When the optimization is conducted based on the exergoeconomics, the overall exergoeconomic factor, the total cost rate and the total exergy destruction cost rate are 55.2%, 20,752 $/h and 9292 $/h, respectively.

  11. Scrubbing system design for CO2 capture in coal-fired power plants

    International Nuclear Information System (INIS)

    Heischkamp, Elizabeth

    2017-01-01

    Within the last decades a continuous tightening of environmental regulations has been observed in several countries around the world. These include restriction of anthropogenic CO 2 emissions, since they are considered responsible for intensifying global warming. Coal-fired power plants represent a good possibility for capturing CO 2 before it is emitted in the atmosphere, thereby contributing to combat global warming. This work focuses on reducing the CO 2 emissions of such a power plant by 90 %. For this purpose a hard coal power plant is retrofitted with a chemical absorption using different solutions of piperazine promoted potassium carbonate. The resulting power plant's efficiency losses have been accounted for. A comparison of different scenarios such as the variation of operating parameters offer an insight in detecting suitable operating conditions that will allow to minimize efficiency penalties. Simulation details are provided along with a technical and an economic analysis.

  12. Performance comparison and parametric optimization of subcritical Organic Rankine Cycle (ORC) and transcritical power cycle system for low-temperature geothermal power generation

    International Nuclear Information System (INIS)

    Shengjun, Zhang; Huaixin, Wang; Tao, Guo

    2011-01-01

    Research highlights: → We conduct the thermodynamic and economic performance comparison of the fluids in both subcritical ORC and transcritical power cycle. → We perform parameter optimization based on five indicators. → The optimum operation parameters and working fluids are not the same for different indicators. → The LEC value is used as the determining factor for fluids screening. → The transcritical power cycle with R125 as the working fluid was a cost-effective approach. - Abstract: Organic Rankine Cycle (ORC) is a promising technology for converting the low-grade energy to electricity. This paper presents an investigation on the parameter optimization and performance comparison of the fluids in subcritical ORC and transcritical power cycle in low-temperature (i.e. 80-100 o C) binary geothermal power system. The optimization procedure was conducted with a simulation program written in Matlab using five indicators: thermal efficiency, exergy efficiency, recovery efficiency, heat exchanger area per unit power output (APR) and the levelized energy cost (LEC). With the given heat source and heat sink conditions, performances of the working fluids were evaluated and compared under their optimized internal operation parameters. The optimum cycle design and the corresponding operation parameters were provided simultaneously. The results indicate that the choice of working fluid varies the objective function and the value of the optimized operation parameters are not all the same for different indicators. R123 in subcritical ORC system yields the highest thermal efficiency and exergy efficiency of 11.1% and 54.1%, respectively. Although the thermal efficiency and exergy efficiency of R125 in transcritical cycle is 46.4% and 20% lower than that of R123 in subcritical ORC, it provides 20.7% larger recovery efficiency. And the LEC value is relatively low. Moreover, 22032L petroleum is saved and 74,019 kg CO 2 is reduced per year when the LEC value is used as

  13. Features of supercritical carbon dioxide Brayton cycle coupled with reactor

    International Nuclear Information System (INIS)

    Duan Chengjie; Wang Jie; Yang Xiaoyong

    2010-01-01

    In order to obtain acceptable cycle efficiency, current helium gas turbine power cycle technology needs high cycle temperature which means that the cycle needs high core-out temperature. The technology has high requirements on reactor structure and fuel elements materials, and also on turbine manufacture. While utilizing CO 2 as cycle working fluid, it can guarantee to lower the cycle temperature and turbo machine Janume but achieve the same cycle efficiency, so as to enhance the safety and economy of reactor. According to the laws of thermodynamics, a calculation model of supercritical CO 2 power cycle was established to analyze the feature, and the decisive parameters of the cycle and also investigate the effect of each parameter on the cycle efficiency in detail were obtained. The results show that supercritical CO 2 power cycle can achieve quite satisfied efficiency at a lower cycle highest temperature than helium cycle, and CO 2 is a promising working fluid. (authors)

  14. Measurement of CO{sub 2}, CO, SO{sub 2}, and NO emissions from coal-based thermal power plants in India

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, N.; Mukheriee, I.; Santra, A.K.; Chowdhury, S.; Chakraborty, S.; Bhattacharya, S.; Mitra, A.P.; Sharma, C. [Jadavpur University, Calcutta (India). Dept. of Power Engineering

    2008-02-15

    Measurements of CO{sub 2} (direct GHG) and CO, SO{sub 2}, NO (indirect GHGs) were conducted on-line at some of the coal-based thermal power plants in India. The objective of the study was three-fold: to quantify the measured emissions in terms of emission coefficient per kg of coal and per kWh of electricity, to calculate the total possible emission from Indian thermal power plants, and subsequently to compare them with some previous studies. Instrument IMR 2800P Flue Gas Analyzer was used on-line to measure the emission rates Of CO{sub 2}, CO, SO{sub 2}, and NO at 11 numbers of generating units of different ratings. Certain quality assurance (QA) and quality control (QC) techniques were also adopted to gather the data so as to avoid any ambiguity in subsequent data interpretation. For the betterment of data interpretation, the requisite statistical parameters (standard deviation and arithmetic mean) for the measured emissions have been also calculated. The emission coefficients determined for CO{sub 2}, CO, SO{sub 2}, and NO have been compared with their corresponding values as obtained in the studies conducted by other groups. The total emissions of CO{sub 2}, CO, SO{sub 2}, and NO calculated on the basis of the emission coefficients for the year 2003-2004 have been found to be 465.667, 1.583, 4.058, and 1.129 Tg, respectively.

  15. Nuclear design report for Yonggwang nuclear power plant unit 4 cycle 2

    International Nuclear Information System (INIS)

    Park, Chan Oh; Park, Sang Yoon; Yoo, Choon Sung; Ryu, Hyo Sang; Park, Jin Ha; Cho, Young Chul; Song, Jae Woong; Lee Chung Chan.

    1996-10-01

    This report presents nuclear design calculations for Cycle 2 of Yonggwang Unit 4. Information is given on fuel loading, power density distributions, reactivity coefficients, control rod worths, and operational limits. In addition, the report contains necessary data for the startup tests and for the assurance of shutdown margin during reactor operation. The reload core consists of 48 fresh KSFAs. Among the 48 fresh KSFAs, 32 fuel assemblies contain burnable poison rods. The fuel assemblies in the core are arranged in a low leakage loading pattern. The cycle length of Cycle 2 amounts to 275 EFPD corresponding to a cycle burnup of 10,100 MWD/MTU. (author). 31 tabs., 92 figs., 7 refs

  16. Development of pre-combustion decarbonization technologies for zero-CO{sub 2} power generation

    Energy Technology Data Exchange (ETDEWEB)

    Werner Renzenbrink; Karl-Josef Wolf; Frank Hannemann; Gerhard Zimmermann; Erik Wolf [RWE Power AG, Essen (Germany)

    2006-07-01

    The drastic rise in power generation that is expected on a global scale will also lead to a strong increase in CO{sub 2} emissions due to the high share of fossil energy sources used, which is quite contrary to the objectives of climate protection. In this dilemma, zero-CO{sub 2} power generation technologies might permit to make a decisive step on the road toward a necessary CO{sub 2} reduction. In the integrated ENCAP project (EU FP 6), a consortium of engineering companies, power plant manufacturers and research institutes lead-managed by RWE Power is drawing up technical IGCC/IRCC concepts including CO{sub 2} capture and spurring the necessary development of new gas turbine burners for the combustion of hydrogen-rich gases. Based on the working structure within ENCAP, this paper is divided into two parts. In the first part, the results of the process development for the different concepts based on hard coal, lignite and natural gas including CO{sub 2} capture is presented giving the technical and economic key figures of the processes. In the second part, the current status of burner development for the combustion of H{sub 2}-rich gases within ENCAP is given. 1 ref., 9 figs., 2 tabs.

  17. The role of pCO2 in astronomically-paced climate and carbon cycle variations in the Middle Miocene

    Science.gov (United States)

    Penman, D. E.; Hull, P. M.; Scher, H.; Kirtland Turner, S.; Ridgwell, A.

    2017-12-01

    The pace of Earth's background climate variability is known to be driven by the Milankovitch cycles, variations in Earth's orbital parameters and axial tilt. While the Milankovitch (orbital) theory of climate change is very nearly universally accepted, the climate system mechanisms and feedbacks responsible for amplifying orbital cycles preserved in the geologic record remain uncertain. For the late Pleistocene, the ice core-derived record of atmospheric carbon dioxide (pCO2) is strongly coupled with global temperature on orbital time scales, indicating that internal feedbacks involving the carbon cycle amplify or even cause the large changes in global temperature during orbitally driven glacial-interglacial cycles. However, for earlier time periods beyond the range of ice cores (the last 800 kyr), it is not possible to directly compare records of pCO2 to orbital climate cycles because there are no high-resolution (orbitally resolved) records of pCO2 before the Pliocene. We address this deficiency with a high-resolution ( 5-10 kyr spacing) record of planktonic foraminiferal d11B-derived surface seawater pH (as well as d13C and trace metal analyses) over a 500 kyr time window in a sedimentary record with known Milankovitch-scale climate and carbon cycle oscillations: the Middle Miocene (14.0 - 14.5 Ma) at ODP Site 926 (subtropical North Atlantic). The resulting pH record can be used to constrain atmospheric pCO2, allowing comparison of the timescale and magnitude of carbon cycle changes during a period of eccentricity-dominated variability in the response of the global climate system (the Late Pleistocene) with a period of obliquity-dominance (the middle Miocene). These new records of planktic d11B and d13C will then be used to guide simulations of astronomical climate forcing in Earth System models, resulting in refined estimates of pCO2 changes over orbital cycles and providing quantitative constraints on the mechanisms and feedbacks responsible for the

  18. Study of CO{sub 2} capture processes in power plants; Etude de procedes de captage du CO{sub 2} dans les centrales thermiques

    Energy Technology Data Exchange (ETDEWEB)

    Amann, J.M

    2007-12-15

    The aim of the present study is to assess and compare various processes aiming at recover CO{sub 2} from power plants fed with natural gas (NGCC) and pulverized coal (PC). These processes are post-combustion CO{sub 2} capture using chemical solvents, natural gas reforming for pre-combustion capture by methanol and oxy-fuel combustion with cryogenic recovery of CO{sub 2}. These processes were evaluated using the process software Aspen PlusTM to give some clues for choosing the best option for each type of power plant. With regard to post-combustion, an aqueous solution based on a mixture of amines (N-methyldiethanolamine (MDEA) and triethylene tetramine (TETA)) was developed. Measurements of absorption were carried out between 298 and 333 K in a Lewis cell. CO{sub 2} partial pressure at equilibrium, characteristic of the CO{sub 2} solubility in the solvent, was determined up to 393 K. The solvent performances were compared with respect to more conventional solvents such as MDEA and monoethanolamine (MEA). For oxy-fuel combustion, a recovery process, based on a cryogenic separation of the components of the flue gas, was developed and applied to power plants. The study showed that O{sub 2} purity acts on the CO{sub 2} concentration in the flue gas and thus on the performances of the recovery process. The last option is natural gas reforming with CO{sub 2} pre-combustion capture. Several configurations were assessed: air reforming and oxygen reforming, reforming pressure and dilution of the synthesis gas. The comparison of these various concepts suggests that, in the short and medium term, chemical absorption is the most interesting process for NGCC power plants. For CP power plants, oxy-combustion can be a very interesting option, as well as post-combustion capture by chemical solvents. (author)

  19. IGSC: using rocket science for increased power, 100% CO{sub 2} capture, and no NOx or SOx

    Energy Technology Data Exchange (ETDEWEB)

    Griffiths, J. [Jacobs Engineering, London (United Kingdom)

    2009-02-15

    The integrated gasification steam cycle (IGSC) is a new way of generating electricity from coal, which, when backfitted to an existing coal fired power plant, not only increases power output substantially but also allows 100% removal of carbon dioxide. The basic concept of IGSC is gasification of coal in a quench gasifier, followed by combustion of the resulting syngas, with oxygen and water, in a modified gas turbine fitted with a novel form of oxy-burner, derived from rocket technology, the CES burner. This turbine, which has no compressor and is called the 'fired expander', drives a generator. The exhaust from the combustion is passed through an HRSG and the resulting steam used to generate further electricity. Downstream of the HRSG, the exhaust gases, which consist of steam mixed with CO{sub 2}, are directly quenched with circulating cold water to condense all the stream, leaving the CO{sub 2} to be collected and compressed. It was decided to concentrate the main development and evaluation of the IGSC process on the retrofit case, focusing on the retrofit of 500 MWe power plants in the UK, with a consequent need for flexibility in operation. 12 figs., 1 tab.

  20. Integrated gasification combined cycle and the capture of CO{sub 2}: a solution for the mitigation of the CO{sub 2} emissions of coal fired power plants at large scale in the short term?; O ciclo combinado com gaseificacao integrada e a captura de CO{sub 2}: uma solucao para mitigar as emissoes de CO{sub 2} em termeletricas a carvao em larga escala no curto prazo?

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Bettina Susanne

    2010-03-15

    The power sector of many big economies still relies heavily on coal fired plants and emits huge amounts of carbon dioxide (CO{sub 2}). The Integrated Gasification Combined Cycle (IGCC) is an innovative technology which holds advantages over current conventional coal technologies, including higher efficiency, pathway to carbon capture and storage (CCS) and higher product and fuel flexibility. The most critical obstacles for commercialization of IGCC technology are higher costs, lower reliability, and little operating experiences. The present work aims to analyze the maturity and the costs of the IGCC technology, with and without CCS, in order to evaluate its potential to be introduced in the generation fleet at big scale in the short term and, hence, its potential to guarantee the possibility to use coal in the power sector without compromising the effort to reduce CO{sub 2} emissions. The focus of the analysis of the technical viability concentrates strongly on the gasification process, since it the most critical process for the operation of the plant. The cost analysis contains three steps: a revision of cost estimates in scientific literature, a revision of reported cost for actually planned projects and a cost simulation that aims to analyze the influences of assumptions regarding the additional technology risk of IGCC plants. (author)

  1. Calcium and chemical looping technology for power generation and carbon dioxide (CO2) capture solid oxygen- and CO2-carriers

    CERN Document Server

    Fennell, Paul

    2015-01-01

    Calcium and Chemical Looping Technology for Power Generation and Carbon Dioxide (CO2) Capture reviews the fundamental principles, systems, oxygen carriers, and carbon dioxide carriers relevant to chemical looping and combustion. Chapters review the market development, economics, and deployment of these systems, also providing detailed information on the variety of materials and processes that will help to shape the future of CO2 capture ready power plants. Reviews the fundamental principles, systems, oxygen carriers, and carbon dioxide carriers relevant to calcium and chemical loopingProvi

  2. Effect of Uncertainties in CO2 Property Databases on the S-CO2 Compressor Performance

    International Nuclear Information System (INIS)

    Lee, Je Kyoung; Lee, Jeong Ik; Ahn, Yoonhan; Kim, Seong Gu; Cha, Je Eun

    2013-01-01

    Various S-CO 2 Brayton cycle experiment facilities are on the state of construction or operation for demonstration of the technology. However, during the data analysis, S-CO 2 property databases are widely used to predict the performance and characteristics of S-CO 2 Brayton cycle. Thus, a reliable property database is very important before any experiment data analyses or calculation. In this paper, deviation of two different property databases which are widely used for the data analysis will be identified by using three selected properties for comparison, C p , density and enthalpy. Furthermore, effect of above mentioned deviation on the analysis of test data will be briefly discussed. From this deviation, results of the test data analysis can have critical error. As the S-CO 2 Brayton cycle researcher knows, CO 2 near the critical point has dramatic change on thermodynamic properties. Thus, it is true that a potential error source of property prediction exists in CO 2 properties near the critical point. During an experiment data analysis with the S-CO 2 Brayton cycle experiment facility, thermodynamic properties are always involved to predict the component performance and characteristics. Thus, construction or defining of precise CO 2 property database should be carried out to develop Korean S-CO 2 Brayton cycle technology

  3. Development of the System Dynamics Code using Homogeneous Equilibrium Model for S-CO{sub 2} Brayton cycle Transient Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Seong Jun; Lee, Won Woong; Oh, Bongseong; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2016-10-15

    The features of the S-CO{sub 2} Brayton cycle come from a small compressing work by designing the compressor inlet close the critical point of CO{sub 2}. This means the system condition can be operating under two-phase or sub-critical phase during transient situations such as changes of cooling system performance, load variations, etc. Since there is no operating MW scale S-CO{sub 2} Brayton cycle system in the world yet, using an analytical code is the only way to predict the system behavior and develop operating strategies of the S-CO{sub 2} Brayton cycles. Therefore, the development of a credible system code is an important part for the practical S-CO{sub 2} system research. The current status of the developed system analysis code for S-CO{sub 2} Brayton cycle transient analyses in KAIST and verification results are presented in this paper. To avoid errors related with convergences of the code during the phase changing flow calculation in GAMMA+ code, the authors have developed a system analysis code using Homogeneous Equilibrium Model (HEM) for the S-CO{sub 2} Brayton cycle transient analysis. The backbone of the in-house code is the GAMMA+1.0 code, but treating the quality of fluid by tracking system enthalpy gradient every time step. Thus, the code adopts pressure and enthalpy as the independent scalar variables to track the system enthalpy for updating the quality of the system every time step. The heat conduction solving method, heat transfer correlation and frictional losses on the pipe are referred from the GAMMA+ code.

  4. CO2-neutral fuels

    Directory of Open Access Journals (Sweden)

    Goede A. P. H.

    2015-01-01

    cycle is established by powering the conversion step by renewable energy and recapturing the CO2 emitted after combustion, ultimately from the surrounding air to cover emissions from distributed source. Carbon Capture and Utilisation (CCU coupled to P2G thus creates a CO2-neutral energy system based on synthetic hydrocarbon fuel. It would enable a circular economy where the carbon cycle is closed by recovering the CO2 emitted after reuse of synthetic hydrocarbon fuel. The critical step, technically as well as economically, is the conversion of feedstock CO2/H2O into syngas rather than the capture of CO2 from ambient air.

  5. Critical impact of vegetation physiology on the continental hydrologic cycle in response to increasing CO2

    Science.gov (United States)

    Lemordant, Léo; Gentine, Pierre; Swann, Abigail S.; Cook, Benjamin I.; Scheff, Jacob

    2018-04-01

    Predicting how increasing atmospheric CO2 will affect the hydrologic cycle is of utmost importance for a range of applications ranging from ecological services to human life and activities. A typical perspective is that hydrologic change is driven by precipitation and radiation changes due to climate change, and that the land surface will adjust. Using Earth system models with decoupled surface (vegetation physiology) and atmospheric (radiative) CO2 responses, we here show that the CO2 physiological response has a dominant role in evapotranspiration and evaporative fraction changes and has a major effect on long-term runoff compared with radiative or precipitation changes due to increased atmospheric CO2. This major effect is true for most hydrological stress variables over the largest fraction of the globe, except for soil moisture, which exhibits a more nonlinear response. This highlights the key role of vegetation in controlling future terrestrial hydrologic response and emphasizes that the carbon and water cycles are intimately coupled over land.

  6. Modern combined cycle power plant utilizing the GT11N2

    International Nuclear Information System (INIS)

    Goodwin, J.C.

    1992-01-01

    The requirement imposed on modern power plants are increasingly demanding. The limits of: efficiency; environmental sensitivity; reliability and availability; are constantly being pushed. Today's state of the art combined cycle power plants are positioned well to meet these challenges. This paper reports that these objectives can be achieved through the selection of the proper gas turbine generator in an optimized cycle concept. A balanced approach to the plant design is required. It must not sacrifice any one of these requirements, in order to achieve the others. They achieve their fullest potential when firing a clean fuel, natural gas. However, fuel oil, both light (No. 2) and heavy (No. 6), can be utilized but some efficiency and environmental impact will have to be sacrificed

  7. Gas power plant with CO2 handling. A study of alternative technologies

    International Nuclear Information System (INIS)

    Bolland, Olav; Hagen, Roger I.; Maurstad, Ola; Tangen, Grethe; Juliussen, Olav; Svendsen, Hallvard

    2002-01-01

    The report documents a study which compares 12 different technologies for gas power plants with CO 2 handling. The additional costs in removing the CO 2 in connection with electricity production is calculated to at least 18-19 oere /kWh compared to conventional gas power production without CO 2 capture. The calculated extra costs are somewhat higher than previously published figures. The difference is mainly due to that the estimated costs for pipelines and injection system for CO 2 are higher than in other studies. The removal of CO 2 in connection with gas power production implies increased use of natural gas. The most developed technologies would lead to a procentual increase in the gas consumption per kWh electricity of 18-25%. Gas power plants based on the present technologies would have efficiencies in the size of 46-49%. The efficiency of power plants without CO 2 handling is supposed to be 58%. There is no foundation for pointing out a ''winner's' among the compared technologies in the study. The present available technologies excepted, there are no technology which stands out as better than the others from an economic viewpoint. Gas turbine with membrane based separation of oxygen from air (AZEP) has a potential for lower costs but implies challenging technological development and thence considerable technological risks. Two technologies, capture of carbon from natural gas previous to combustion and exhaust gas purification based on absorption, may be employed in 3 - 4 years. The other technologies require more development and maturing. Three of the technologies may be particularly interesting because hydrogen may be produced as a byproduct. Demonstration plant and choice of technology: 1) There is a limited need for demonstration plants with respect to technology development. 2) It is important for the technology development to be able to test various technologies in a laboratory or in a flexible pilot plant. 3) Many technologies and components may be

  8. Alteration in reactor installation (addition of Unit 2) in Shimane Nuclear Power Station, Chugoku Electric Power Co., Inc. (inquiry)

    International Nuclear Information System (INIS)

    1983-01-01

    An inquiry was made by the Ministry of International Trade and Industry to Nuclear Safety Commission on the addition of Unit 2 in Shimane Nuclear Power Station of The Chugoku Electric Power Co., Inc., concerning the technical capability of Chugoku Electric Power Co., Inc., and the plant safety. The NSC requested the Committee on Examination of Reactor Safety to make a deliberation on this subject. Both the technical capability and the safety of Unit 1 were already confirmed by MITI. Unit 2 to be newly added in the Shimane Nuclear Power Station is a BWR power plant with electric output of 820 MW. The examination made by MITI is described: the technical capability of Chugoku Electric Power Co., Inc., the safety of Unit 2 about its siting, reactor proper, reactor cooling system, radioactive waste management, etc. (J.P.N.)

  9. Nuclear design report for Yonggwang nuclear power plant unit 3 cycle 2

    Energy Technology Data Exchange (ETDEWEB)

    Zee, Sung Kyun; Song, Jae Woong; Song, Jae Seung; Park, Sang Yoon; Yoo, Choon Sung; Baek, Byung Chan; Ryu, Hyo Sang; Park, Jin Ha; Cho, Young Chul [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-01-01

    This report presents nuclear design calculations for Cycle 2 of Yonggwang Unit 3. Information is given on fuel loading, power density distributions, reactivity coefficients, control rod worths, and operational limits. In addition, the report contains necessary data for the startup tests and for the assurance of shutdown margin during reactor operation. The reload core consists of 48 fresh Korean Standard Fuel Assemblies (KSFAs)and 129 burned KSFAs. Among the 48 fresh KSFAs, 32 fuel assemblies contain burnable poison rods. The fuel assemblies in the core are arranged in a low leakage loading pattern. The cycle length of Cycle 2 amounts to 276 EFPD corresponding to a cycle burnup of 10,160 MWD/MTU. 95 figs., 31 tabs., 7 refs. (Author) .new.

  10. High electrochemical energy storage in self-assembled nest-like CoO nanofibers with long cycle life

    Energy Technology Data Exchange (ETDEWEB)

    Pramanik, Atin; Maiti, Sandipan [CSIR-Central Glass & Ceramic Research Institute, Fuel Cell & Battery Division (India); Sreemany, Monjoy [CSIR-Central Glass & Ceramic Research Institute, Advanced Mechanical and Materials Characterization Division (India); Mahanty, Sourindra, E-mail: mahanty@cgcri.res.in [CSIR-Central Glass & Ceramic Research Institute, Fuel Cell & Battery Division (India)

    2016-04-15

    Developing efficient electrode material is essential to keep pace with the demand for high energy density together with high power density and long cycle life in next generation energy storage devices. Herein, we report the electrochemical properties of hydrothermally synthesized CoO nanofibers of diameter 30–80 nm assembled in a nest-like morphology which showed a very high reversible lithium storage capacity of 2000 mA h g{sup −1} after 600 cycles at 0.1 mA cm{sup −2} as lithium-ion battery anode. Systematic investigation by ex situ transmission electron microscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, and impedance spectroscopy at different cycling stages indicated that the extraordinary performance could be related to an enhancement in the Co{sup 2+}↔Co{sup x+} (2 < x ≤ 3) redox process in addition to the commonly believed structural and morphological evolution during cycling favoring generation of large number of accessible active sites for lithium insertion. Further, when examined as a supercapacitor electrode in 1.0 M KOH, a capacitance of 1167 F g{sup −1} is achieved from these 1D CoO nanofibers after 10,000 charge discharge cycles at a high current density of 5 A g{sup −1} demonstrating good application potential.Graphical AbstractNest-like CoO nanofibers showed a reversible lithium storage capacity of 2000 mA h g{sup −1} after 600 cycles as LIB anode and a capacitance of 1167 F g{sup −1} after 10,000 cycles as electrochemical supercapacitor.

  11. Technical and economic assessment of the integrated solar combined cycle power plants in Iran

    International Nuclear Information System (INIS)

    Soltani Hosseini, M.; Hosseini, R.; Valizadeh, G.H.

    2002-01-01

    Thermal efficiency, capacity factor, environmental considerations, investment cost, fuel and O and M costs are the main parameters for technical and economic assessment of solar power plants. This analysis has shown that the Integrated Solar Combined Cycle System with 67 MW e solar field(ISCCS-67) is the most suitable plan for the first solar power plant in Iran. The Levelized Energy Costs of combined cycle and ISCCS-67 power plants would be equal if 49 million dollars of ISCCS-67 capital cost supplied by the international environmental organizations such as Global Environmental Facilities and World Bank. This study shows that an ISCCS-67 saves 59 million dollars in fuel consumption and reduces about 2.4 million ton in CO 2 emission during 30 years operating period. Increasing of steam turbine capacity by 50%, and 4% improvement in overall efficiency are other advantages of iSCCS-67 power plant. The LEC of ISCCS-67 is 10% and so 33% lower than the combined cycle and gas turbine, respectively, at the same capacity factor with consideration of environmental costs

  12. Development of high-power CO2 lasers and laser material processing

    Science.gov (United States)

    Nath, Ashish K.; Choudhary, Praveen; Kumar, Manoj; Kaul, R.

    2000-02-01

    Scaling laws to determine the physical dimensions of the active medium and optical resonator parameters for designing convective cooled CO2 lasers have been established. High power CW CO2 lasers upto 5 kW output power and a high repetition rate TEA CO2 laser of 500 Hz and 500 W average power incorporated with a novel scheme for uniform UV pre- ionization have been developed for material processing applications. Technical viability of laser processing of several engineering components, for example laser surface hardening of fine teeth of files, laser welding of martensitic steel shroud and titanium alloy under-strap of turbine, laser cladding of Ni super-alloy with stellite for refurbishing turbine blades were established using these lasers. Laser alloying of pre-placed SiC coating on different types of aluminum alloy, commercially pure titanium and Ti-6Al-4V alloy, and laser curing of thermosetting powder coating have been also studied. Development of these lasers and results of some of the processing studies are briefly presented here.

  13. An improved CO_2-based transcritical Rankine cycle (CTRC) used for engine waste heat recovery

    International Nuclear Information System (INIS)

    Shu, Gequn; Shi, Lingfeng; Tian, Hua; Li, Xiaoya; Huang, Guangdai; Chang, Liwen

    2016-01-01

    Highlights: • Propose an improved CTRC system (PR-CTRC) for engine waste heat recovery. • The PR-CTRC achieves a significant increase in thermodynamic performance. • The PR-CTRC possesses a strong coupling capability for high and low grade waste heat. • The PR-CTRC uses smaller turbine design parameters than ORC systems. • Total cooling load analysis of combined engine and recovery system was conducted. - Abstract: CO_2-based transcritical Rankine cycle (CTRC) is a promising technology for the waste heat recovery of an engine considering its safety and environment friendly characteristics, which also matchs the high temperature of the exhaust gas and satisfies the miniaturization demand of recovery systems. But the traditional CTRC system with a basic configuration (B-CTRC) has a poor thermodynamic performance. This paper introduces an improved CTRC system containing both a preheater and regenerator (PR-CTRC), for recovering waste heat in exhaust gas and engine coolant of an engine, and compares its performance with that of the B-CTRC system and also with that of the traditional excellent Organic Rankine Cycle (ORC) systems using R123 as a working fluid. The utilization rate of waste heat, total cooling load, net power output, thermal efficiency, exergy loss, exergy efficiency and component size have been investigated. Results show that, the net power output of the PR-CTRC could reach up to 9.0 kW for a 43.8 kW engine, which increases by 150% compared with that of the B-CTRC (3.6 kW). The PR-CTRC also improves the thermal efficiency and exergy efficiency of the B-CTRC, with increases of 184% and 227%, respectively. Compared with the ORC system, the PR-CTRC shows the significant advantage of highly recycling the exhaust gas and engine coolant simultaneously due to the special property of supercritical CO_2’s specific heat capacity. The supercritical property of CO_2 also generates a better heat transfer and flowing performances. Meanwhile, the PR

  14. Optimum gas turbine cycle for combined cycle power plant

    International Nuclear Information System (INIS)

    Polyzakis, A.L.; Koroneos, C.; Xydis, G.

    2008-01-01

    The gas turbine based power plant is characterized by its relatively low capital cost compared with the steam power plant. It has environmental advantages and short construction lead time. However, conventional industrial engines have lower efficiencies, especially at part load. One of the technologies adopted nowadays for efficiency improvement is the 'combined cycle'. The combined cycle technology is now well established and offers superior efficiency to any of the competing gas turbine based systems that are likely to be available in the medium term for large scale power generation applications. This paper has as objective the optimization of a combined cycle power plant describing and comparing four different gas turbine cycles: simple cycle, intercooled cycle, reheated cycle and intercooled and reheated cycle. The proposed combined cycle plant would produce 300 MW of power (200 MW from the gas turbine and 100 MW from the steam turbine). The results showed that the reheated gas turbine is the most desirable overall, mainly because of its high turbine exhaust gas temperature and resulting high thermal efficiency of the bottoming steam cycle. The optimal gas turbine (GT) cycle will lead to a more efficient combined cycle power plant (CCPP), and this will result in great savings. The initial approach adopted is to investigate independently the four theoretically possible configurations of the gas plant. On the basis of combining these with a single pressure Rankine cycle, the optimum gas scheme is found. Once the gas turbine is selected, the next step is to investigate the impact of the steam cycle design and parameters on the overall performance of the plant, in order to choose the combined cycle offering the best fit with the objectives of the work as depicted above. Each alterative cycle was studied, aiming to find the best option from the standpoint of overall efficiency, installation and operational costs, maintainability and reliability for a combined power

  15. Modelling and exergoeconomic-environmental analysis of combined cycle power generation system using flameless burner for steam generation

    International Nuclear Information System (INIS)

    Hosseini, Seyed Ehsan; Barzegaravval, Hasan; Ganjehkaviri, Abdolsaeid; Wahid, Mazlan Abdul; Mohd Jaafar, M.N.

    2017-01-01

    Highlights: • Using flameless burner as a supplementary firing system after gas turbine is modeled. • Thermodynamic, economic and environmental analyses of this model are performed. • Efficiency of the plant increases about 6% and CO_2 emission decreases up to 5.63% in this design. • Available exergy for work production in both gas cycle and steam cycle increases in this model. - Abstract: To have an optimum condition for the performance of a combined cycle power generation, using supplementary firing system after gas turbine was investigated by various researchers. Since the temperature of turbine exhaust is higher than auto-ignition temperature of the fuel in optimum condition, using flameless burner is modelled in this paper. Flameless burner is installed between gas turbine cycle and Rankine cycle of a combined cycle power plant which one end is connected to the outlet of gas turbine (as primary combustion oxidizer) and the other end opened to the heat recovery steam generator. Then, the exergoeconomic-environmental analysis of the proposed model is evaluated. Results demonstrate that efficiency of the combined cycle power plant increases about 6% and CO_2 emission reduces up to 5.63% in this proposed model. It is found that the variation in the cost is less than 1% due to the fact that a cost constraint is implemented to be equal or lower than the design point cost. Moreover, exergy of flow gases increases in all points except in heat recovery steam generator. Hence, available exergy for work production in both gas cycle and steam cycle will increase in new model.

  16. Compressor Modeling for Transient Analysis of Supercritical CO2 Brayton Cycle by using MARS code

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joo Hyun; Park, Hyun Sun; Kim, Tae Ho; Kwon, Jin Gyu [POSTECH, Pohang (Korea, Republic of); Bae, Sung Won; Cha, Jae Eun [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    In this study, SCIEL (Supercritical CO{sub 2} Integral Experimental Loop) was chosen as a reference loop and the MARS code was as the transient cycle analysis code. As a result, the compressor homologous curve was developed from the SCIEL experimental data and MARS analysis was performed and presented in the paper. The advantages attract SCO{sub 2}BC as a promising next generation power cycles. The high thermal efficiency comes from the operation of compressor near the critical point where the properties of SCO{sub 2}. The approaches to those of liquid phase, leading drastically lower the compression work loss. However, the advantage requires precise and smooth operation of the cycle near the critical point. However, it is one of the key technical challenges. The experimental data was steady state at compressor rotating speed of 25,000 rpm. The time, 3133 second, was starting point of steady state. Numerical solutions were well matched with the experimental data. The mass flow rate from the MARS analysis of approximately 0.7 kg/s was close to the experimental result of 0.9 kg/s. It is expected that the difference come from the measurement error in the experiment. In this study, the compressor model was developed and implemented in MARS to study the transient analysis of SCO{sub 2}BC in SCIEL. We obtained the homologous curves for the SCIEL compressor using experimental data and performed nodalization of the compressor model using MARS code. In conclusions, it was found that numerical solutions from the MARS model were well matched with experimental data.

  17. Gasoline-powered serial hybrid cars cause lower life cycle carbon emissions than battery cars

    Science.gov (United States)

    Meinrenken, Christoph J.; Lackner, Klaus S.

    2011-04-01

    Battery cars powered by grid electricity promise reduced life cycle green house gas (GHG) emissions from the automotive sector. Such scenarios usually point to the much higher emissions from conventional, internal combustion engine cars. However, today's commercially available serial hybrid technology achieves the well known efficiency gains from regenerative breaking, lack of gearbox, and light weighting - even if the electricity is generated onboard, from conventional fuels. Here, we analyze emissions for commercially available, state-of the-art battery cars (e.g. Nissan Leaf) and those of commercially available serial hybrid cars (e.g., GM Volt, at same size and performance). Crucially, we find that serial hybrid cars driven on (fossil) gasoline cause fewer life cycle GHG emissions (126g CO2e per km) than battery cars driven on current US grid electricity (142g CO2e per km). We attribute this novel finding to the significant incremental life cycle emissions from battery cars from losses during grid transmission, battery dis-/charging, and larger batteries. We discuss crucial implications for strategic policy decisions towards a low carbon automotive sector as well as relative land intensity when powering cars by biofuel vs. bioelectricity.

  18. Life cycle analysis on carbon emissions from power generation – The nuclear energy example

    International Nuclear Information System (INIS)

    Nian, Victor; Chou, S.K.; Su, Bin; Bauly, John

    2014-01-01

    Highlights: • This paper discusses about a methodology on the life cycle analysis of power generation using nuclear as an example. • The methodology encompasses generic system, input–output, and boundaries definitions. • The boundaries facilitate the use of Kaya Identity and decomposition technique to identify carbon emission streams. - Abstract: A common value of carbon emission factor, t-CO 2 /GWh, in nuclear power generation reported in the literature varies by more than a factor of 100. Such a variation suggests a margin of uncertainty and reliability. In this study, we employ a bottom-up approach to better define the system, its input and output, and boundaries. This approach offers improved granularity at the process level and consistency in the results. Based on this approach, we have developed a methodology to enable comparison of carbon emissions from nuclear power generation. The proposed methodology employs the principle of energy balance on a defined power generation system. The resulting system boundary facilitates the use of the “Kaya Identity” and the decomposition technique to identify the carbon emission streams. Using nuclear power as a case study, we obtained a carbon emission factor of 22.80 t-CO 2 /GWh, which falls to within 2.5% of the median of globally reported LCA results. We demonstrate that the resulting methodology could be used as a generic tool for life cycle analysis of carbon emissions from other power generation technologies and systems

  19. Research report for fiscal 1998. Basic research for promoting joint implementation, etc. (conversion of old coal-fired thermoelectric power plants in Poland into combined cycle plants); 1998 nendo chosa hokokusho. Poland sekitan karyoku hatsudensho (kyushiki) combined cycle eno tenkan

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    A project is discussed for modernization for energy efficiency enhancement and greenhouse gas reduction. The most effective way to reduce greenhouse gas in Poland is to totally replace the existing coal-fired power plants with natural gas combined cycle plants. Under this project, however, natural gas-fired power generation and integrated coal/brown coal gasification combined cycle power generation are both subjected to study. This is because the power plant modernization project is closely related to the fate of coal/brown coal industries which constitute the important industrial department of Poland. As for the earning rate of the project in case of natural gas-fired combined cycle power generation, the rate will be 13.2% even at the Kaweczyn station which is the highest in earning rate, and this fails to satisfy the project conditions. If integrated coal/brown gasification combined cycle power generation is chosen, the rate will be still lower. When the cost for greenhouse gas reduction is taken up, the Konin station exhibits the lowest of 9 dollars/tCO2, and the others 15-17 dollars/tCO2. When coal gas combined cycle is employed, the cost will be 3-4 times higher. (NEDO)

  20. Economic evaluation of pre-combustion CO2-capture in IGCC power plants by porous ceramic membranes

    International Nuclear Information System (INIS)

    Franz, Johannes; Maas, Pascal; Scherer, Viktor

    2014-01-01

    Highlights: • Process simulations of IGCC with pre-combustion capture via membranes were done. • Most promising technology is the water–gas-shift-membrane-reactor (WGSMR). • Energetic evaluations showed minimum efficiency loss of 5.8%-points for WGSMR. • Economic evaluations identified boundary limits of membrane technology. • Cost of electricity for optimum WGSMR-case is 57 €/MW h under made assumptions. - Abstract: Pre-combustion-carbon-capture is one of the three main routes for the mitigation of CO 2 -emissions by fossil fueled power plants. Based on the data of a detailed technical evaluation of CO 2 -capture by porous ceramic membranes (CM) and ceramic membrane reactors (WGSMR) in an Integrated-Gasification-Combined-Cycle (IGCC) power plant this paper focuses on the economic effects of CO 2 -abatement. First the results of the process simulations are presented briefly. The analysis is based on a comparison with a reference IGCC without CO 2 -capture (dry syngas cooling, bituminous coal, efficiency of 47.4%). In addition, as a second reference, an IGCC process with CO 2 removal based on standard Selexol-scrubbing is taken into account. The most promising technology for CO 2 -capture by membranes in IGCC applications is the combination of a water gas shift reactor and a H 2 -selective membrane into one water gas shift membrane reactor. For the WGSRM-case efficiency losses can be limited to about 6%-points (including losses for CO 2 compression) for a CO 2 separation degree of 90%. This is a severe reduction of the efficiency loss compared to Selexol (10.3% points) or IGCC–CM (8.6% points). The economic evaluation is based on a detailed analysis of investment and operational costs. Parameters like membrane costs and lifetime, costs of CO 2 -certificates and annual operating hours are taken into account. The purpose of these evaluations is to identify the minimum cost of electricity for the different capture cases for the variation of the boundary

  1. Nuclear design report for Yonggwang nuclear power plant unit 2 cycle 7

    International Nuclear Information System (INIS)

    Zee, Sung Kyun; Choi, Gyoo Hwan; Lee, Ki Bog; Park, Sang Yoon

    1993-02-01

    This report presents nuclear design calculations for Cycle 7 of Yonggwang Unit 2. Information is given on fuel loading, power density distributions, reactivity coefficients, control rod worths and operational limits. In addition, the report contains all necessary data for the startup tests including predicted values for the comparison with the measured data. The reload consists of 64 KOFA's enriched by nominally 3.70 w/o U235. Among the KOFA's, 40 fuel assemblies contain gadolinia rods. The fuel assemblies in the core are arranged in a low leakage loading pattern. The cycle length of Cycle 7 amounts to 367 EFPD corresponding to a cycle burnup of 14770 MWD/MTU. (Author)

  2. Numerical evaluation of the Kalina cycle for concentrating solar power plants

    DEFF Research Database (Denmark)

    Modi, Anish

    Concentrating solar power plants use a number of reflecting mirrors to focus and convert the incident solar energy to heat, and a power cycle to convert this heat into electricity. One of the key challenges currently faced by the solar industry is the high cost of electricity production. These co...

  3. Spinel FeCo2S4 nanoflower arrays grown on Ni foam as novel binder-free electrodes for long-cycle-life supercapacitors

    Science.gov (United States)

    Deng, Cuifen; Yang, Lishan; Yang, Chunming; Shen, Ping; Zhao, Liping; Wang, Zhiyu; Wang, Chunhui; Li, Junhua; Qian, Dong

    2018-01-01

    Spinel FeCo2S4 nanoflower arrays grown on Ni foam (FeCo2S4@Ni) have been successfully fabricated via a facile hydrothermal sulfurization of the corresponding FeCo2O4 precursor. The results of X-ray diffraction and X-ray photoelectron spectroscopy characterizations affirm that partial Co2+/Co3+ ions in Co3S4 have been substituted by Fe2+/Fe3+ ions to form FeCo2S4. The obtained FeCo2S4@Ni exhibits an ultrahigh specific capacitance (1644.07 mF cm-2 at 50 mA cm-2) and a supreme cycling stability (∼100% after 10,000 cycles at 50 mA cm-2) as binder-free electrodes for supercapacitors. The cycling stability of the fabricated product is the highest among the documented ternary metallic sulfides so far. The excellent supercapacitive performance of FeCo2S4@Ni emanates from the unique architectures of Fe2Co2S4 nanoflower arrays constituted by ultrathin nanoflakes, three-dimensional porous and conductive Ni foam, and solid skeleton of Ni foam for robust connections to the Fe2Co2S4.

  4. Novel Supercritical Carbon Dioxide Power Cycle Utilizing Pressured Oxy-combustion in Conjunction with Cryogenic Compression

    Energy Technology Data Exchange (ETDEWEB)

    Brun, Klaus; McClung, Aaron; Davis, John

    2014-03-31

    The team of Southwest Research Institute® (SwRI) and Thar Energy LLC (Thar) applied technology engineering and economic analysis to evaluate two advanced oxy-combustion power cycles, the Cryogenic Pressurized Oxy-combustion Cycle (CPOC), and the Supercritical Oxy-combustion Cycle. This assessment evaluated the performance and economic cost of the two proposed cycles with carbon capture, and included a technology gap analysis of the proposed technologies to determine the technology readiness level of the cycle and the cycle components. The results of the engineering and economic analysis and the technology gap analysis were used to identify the next steps along the technology development roadmap for the selected cycle. The project objectives, as outlined in the FOA, were 90% CO{sub 2} removal at no more than a 35% increase in cost of electricity (COE) as compared to a Supercritical Pulverized Coal Plant without CO{sub 2} capture. The supercritical oxy-combustion power cycle with 99% carbon capture achieves a COE of $121/MWe. This revised COE represents a 21% reduction in cost as compared to supercritical steam with 90% carbon capture ($137/MWe). However, this represents a 49% increase in the COE over supercritical steam without carbon capture ($80.95/MWe), exceeding the 35% target. The supercritical oxy-combustion cycle with 99% carbon capture achieved a 37.9% HHV plant efficiency (39.3% LHV plant efficiency), when coupling a supercritical oxy-combustion thermal loop to an indirect supercritical CO{sub 2} (sCO{sub 2}) power block. In this configuration, the power block achieved 48% thermal efficiency for turbine inlet conditions of 650°C and 290 atm. Power block efficiencies near 60% are feasible with higher turbine inlet temperatures, however a design tradeoff to limit firing temperature to 650°C was made in order to use austenitic stainless steels for the high temperature pressure vessels and piping and to minimize the need for advanced turbomachinery features

  5. Environmental Assessment for Potential Impacts of Ocean CO2 Storage on Marine Biogeochemical Cycles

    Science.gov (United States)

    Yamada, N.; Tsurushima, N.; Suzumura, M.; Shibamoto, Y.; Harada, K.

    2008-12-01

    Ocean CO2 storage that actively utilizes the ocean potential to dissolve extremely large amounts of CO2 is a useful option with the intent of diminishing atmospheric CO2 concentration. CO2 storage into sub-seabed geological formations is also considered as the option which has been already put to practical reconnaissance in some projects. Direct release of CO2 in the ocean storage and potential CO2 leakage from geological formations into the bottom water can alter carbonate system as well as pH of seawater. It is essential to examine to what direction and extent chemistry change of seawater induced by CO2 can affect the marine environments. Previous studies have shown direct and acute effects by increasing CO2 concentrations on physiology of marine organisms. It is also a serious concern that chemistry change can affect the rates of chemical, biochemical and microbial processes in seawater resulting in significant influences on marine biogeochemical cycles of the bioelements including carbon, nutrients and trace metals. We, AIST, have conducted a series of basic researches to assess the potential impacts of ocean CO2 storage on marine biogeochemical processes including CaCO3 dissolution, and bacterial and enzymatic decomposition of organic matter. By laboratory experiments using a special high pressure apparatus, the improved empirical equation was obtained for CaCO3 dissolution rate in the high CO2 concentrations. Based on the experimentally obtained kinetics with a numerical simulation for a practical scenario of oceanic CO2 sequestration where 50 Mton CO2 per year is continuously injected to 1,000-2,500 m depth within 100 x 333 km area for 30 years, we could illustrate precise 3-D maps for the predicted distributions of the saturation depth of CaCO3, in situ Ω value and CaCO3 dissolution rate in the western North Pacific. The result showed no significant change in the bathypelagic CaCO3 flux due to chemistry change induced by ocean CO2 sequestration. Both

  6. Incorporating IGCC and CaO sorption-enhanced process for power generation with CO2 capture

    International Nuclear Information System (INIS)

    Chen, Shiyi; Xiang, Wenguo; Wang, Dong; Xue, Zhipeng

    2012-01-01

    Highlights: ► CaO sorption-enhanced process is incorporated with IGCC for CO 2 capture. ► IGCC–CCS is simplified using CaO sorption-enhanced process. ► The electricity efficiency is around 31–33% and CO 2 capture efficiency exceeds 95%. ► Parameters such as sorption pressure influence the system performance. -- Abstract: Integrated gasification combined cycle (IGCC) is a power generation technology to convert solid fuels into electricity. IGCC with CCS is regarded as a promising option to mitigate CO 2 emission. In this paper, the CaO sorption-enhanced process is incorporated downstream with coal gasification to produce a hydrogen-rich stream for electricity production and CO 2 separation. A WGS-absorber substitutes the high- and low-temperature water–gas shift reactors and desulfurization units in conventional IGCC–CCS to produce a hydrogen-rich stream, which is sent onto a gas turbine. CaO is used as the sorbent to enhance hydrogen production and for CO 2 capture. Regeneration of CaO is completed via calcination in a regenerator vessel. The IGCC with CaO sorption-enhanced process is modeled and simulated using Aspen Plus software. Two commercial available gasification technologies, Shell and Texaco, are integrated with the sorption-enhanced process. The results showed IGCC with CaO sorption-enhanced process has a satisfactory system performance. Even though the net electricity efficiency is not as high as expected, just around 30–33%, the system has a high CO 2 capture efficiency ∼97% and low pollutant emissions. Moreover, compared with conventional IGCC–CCS, the schematic diagram of the IGCC–CCS process is simplified. Parameters that affect the plant performance are analyzed in the sensitive analysis, including WGS-absorber temperature, H 2 O/CO ratio, pressure, etc. Some challenges to the system are also discussed.

  7. Impact of the economic recession on the European power sector's CO2 emissions

    International Nuclear Information System (INIS)

    Declercq, Bruno; Delarue, Erik; D'haeseleer, William

    2011-01-01

    This paper investigates the impact of the economic recession on CO 2 emissions in the European power sector, during the years 2008 and 2009. Three main determinants of the power sector's emissions are identified: the demand for electricity, the CO 2 price, and fuel prices. A counterfactual scenario has been set up for each of these, i.e., what these parameters would have been if not affected by the recession. A simulation model of the European power sector is then employed, comparing a historical reference simulation (taking the parameters as actually occurred) with the counterfactual scenarios. The lower electricity demand (due to the recession) is shown to have by far the largest impact, accounting for an emission reduction of about 175 Mton. The lower CO 2 price (due to the recession) resulted in an increase in emissions by about 30 Mton. The impact of fuel prices is more difficult to retrieve; an indicative reduction of about 17 Mton is obtained, mainly as a consequence of the low gas prices in 2009. The simulated combined impact of the parameters results in an emission reduction of about 150 Mton in the European power sector over the years 2008 and 2009 as a consequence of the recession. - Research highlights: → CO 2 emissions are simulated for the European power sector. → Emissions reduced drastically because of the economic recession in 2008 and 2009. → Lower electricity demand had highest impact and accounts for reduction of about 175 Mton. → Impact of different CO 2 and fuel prices on emissions is more limited.

  8. Rational design of temperature swing adsorption cycles for post-combustion CO2 capture

    NARCIS (Netherlands)

    Joss, Lisa; Gazzani, Matteo; Mazzotti, Marco

    2017-01-01

    The design of temperature swing adsorption (TSA) cycles aimed at recovering the heavy product at high purity is investigated by model-based design and applied to the capture of CO2 from flue gases. This model based design strategy and an extensive parametric analysis enables gaining an understanding

  9. Techno-economic study of CO{sub 2} capture from an existing coal-fired power plant: MEA scrubbing vs. O{sub 2}/CO{sub 2} recycle combustion

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D; Croiset, E; Douglas, P L [Waterloo Univ., Dept. of Chemical Engineering, Waterloo, ON (Canada); Douglas, M A [Natural Resources Canada, CANMET Energy Technology Centre, Nepean, ON (Canada)

    2003-11-01

    The existing fleet of modern pulverised coal fired power plants represents an opportunity to achieve significant reductions in greenhouse gas emissions in the coming years providing that efficient and economical CO{sub 2} capture technologies are available for retrofit. One option is to separate CO{sub 2} from the products of combustion using conventional approaches such as amine scrubbing. An emerging alternative, commonly known as O{sub 2}/CO{sub 2} recycle combustion, involves burning the coal with oxygen in an atmosphere of recycled flue gas. Both approaches can be retrofitted to existing units, however they consume significant amounts of energy to capture, purify and compress the CO{sub 2} for subsequent sequestration. This paper presents a techno-economic comparison of the performance of the two approaches. The comparison was developed using the commercial process simulation packages, Hysys and Aspen Plus. The results show that both processes are expensive options to capture CO{sub 2} from coal power plants, however O{sub 2}/CO{sub 2} appears to be a more attractive retrofit than MEA scrubbing. The CO{sub 2} capture cost for the MEA case is USD 53/ton of CO{sub 2} avoided, which translates into 3.3 cent/kW h. For the O{sub 2}/CO{sub 2} case the CO{sub 2} capture cost is lower at USD 35/ton of CO{sub 2} avoided, which translates into 2.4 cent/kW h. These capture costs represent an approximate increase of 20-30% in current electricity prices. (Author)

  10. Self Powered Non-Dispersive Infra-Red CO{sub 2} Gas Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, D R; MacGregor, C, E-mail: des@gassensing.co.uk [Gas Sensing Solutions Ltd, 60 Grayshill Road, Westfield North Courtyard, Glasgow G68 9HQ (United Kingdom)

    2011-08-17

    This paper describes a non-dispersive infra-red CO{sub 2} gas sensor, incorporating a mid-infra-red solid state light source/ detector combination, tuned to match the spectral absorption characteristic of CO{sub 2} gas. Injection moulded optics provide low cost manufacture. Continuous operation power consumption is < 3.5mW and pulsed mode with energy per measurement < 6mJ. Self powered operation using a solar cell is demonstrated together with wireless capability. Performance of two path length variants (20mm and 70mm) is described. The sensor shows invariant temperature output characteristic from -25 to 50 deg. C. Accuracy level is typically {+-}3% of reading.

  11. Nuclear design report for Ulchin nuclear power plant unit 2, cycle 6

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chan Oh; Park, Jin Ha; Kim, Yong Rae; Park, Sang Yoon; Lee, Jong Chul; Baik, Joo Hyun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-08-01

    This report presents nuclear design calculations for cycle 6 of Ulchin unit 2. Information is given on fuel loading, power density distributions, reactivity coefficients, control rod worths and operational limits. In addition, the report contains all necessary data for the startup tests including predicted values for the comparison with the measured data. The reload consists of 64 KOFA`s enriched by nominally 3.80 w/o U{sub 235}. Among the KOFA`s, 36 fuel assemblies contain gadolinia rods. The fuel assemblies in the core are arranged in a low leakage loading pattern. The cycle length of cycle 6 amounts to 388 EFPD corresponding to a cycle burnup of 15610 MWD/MTU. (Author) 8 refs., 55 figs., 17 tabs.

  12. Nuclear design report for Ulchin nuclear power plant unit 2 cycle 5

    International Nuclear Information System (INIS)

    Park, Jin Ha; Park, Yong Soo; Cho, Byeong Ho; Zee, Sung Kyun; Lee, Sang Keun; Ahn, Dawk Hwan

    1993-09-01

    This report presents nuclear design calculations for cycle 5 of Ulchin unit it 2. Information is given on fuel loading, power density distributions, reactivity coefficients, control rod worths and operational limits. In addition, the report contains all necessary data for the startup tests including predicted values for the comparison with the measured data. The reload consists of 48 KOFA's enriched by nominally 3.50 w/o U 235 . Among the KOFA's, 20 fuel assemblies contain gadolinia rods. The fuel assemblies in the core are arranged in a low leakage loading pattern. The cycle length of cycle 5 amounts to 293 EFPD corresponding to a cycle burnup of 11780 MWD/MTU. (Author) 8 refs., 55 figs., 16 tabs

  13. Sulphation and carbonation properties of hydrated sorbents from a fluidized bed CO{sub 2} looping cycle reactor

    Energy Technology Data Exchange (ETDEWEB)

    Vasilije Manovic; Edward J. Anthony; Dennis Y. Lu [CANMET Energy Technology Centre-Ottawa, Ottawa, ON (Canada)

    2008-10-15

    Sulphation and carbonation have been performed on hydrated spent residues from a 75 kW{sub th} dual fluidized bed combustion (FBC) pilot plant operating as a CO{sub 2} looping cycle unit. The sulphation and carbonation tests were done in an atmospheric pressure thermogravimetric analyzer (TGA), with the sulphation performed using synthetic flue gas (0.45% SO{sub 2}, 3% O{sub 2}, 15% CO{sub 2} and N{sub 2} balance). Additional tests were carried out in a tube furnace (TF) with a higher SO{sub 2} concentration (1%) and conversions were determined by quantitative X-ray diffraction (QXRD) analyses. The morphology of the sulphated samples from the TF was examined by scanning electron microscopy (SEM). Sulphation tests were performed at 850{sup o}C for 150 min and carbonation tests at 750{sup o}C, 10 cycles for 15 min (7.5 min calcination + 7.5 min carbonation). Sulphation conversions obtained for the hydrated samples depended on sample type: in the TGA, they were 75-85% (higher values were obtained for samples from the carbonator); and in the TF, values around 90% and 70% for sample from carbonator and calciner, respectively, were achieved, in comparison to the 40% conversion seen with the original sample. The SEM analyses showed significant residual porosity that can increase total conversion with longer sulphation time. The carbonation tests showed a smaller influence of the sample type and typical conversions after 10 cycles were 50% - about 10% higher than that for the original sample. The influence of hydration duration, in the range of 15-60 min, is not apparent, indicating that samples are ready for use for either SO{sub 2} retention, or further CO{sub 2} capture after at most 15 min using saturated steam. The present results show that, upon hydration, spent residues from FBC CO{sub 2} capture cycles are good sorbents for both SO{sub 2} retention and additional CO{sub 2} capture. 33 refs., 10 figs., 2 tabs.

  14. Scrubbing system design for CO{sub 2} capture in coal-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Heischkamp, Elizabeth

    2017-07-01

    Within the last decades a continuous tightening of environmental regulations has been observed in several countries around the world. These include restriction of anthropogenic CO{sub 2} emissions, since they are considered responsible for intensifying global warming. Coal-fired power plants represent a good possibility for capturing CO{sub 2} before it is emitted in the atmosphere, thereby contributing to combat global warming. This work focuses on reducing the CO{sub 2} emissions of such a power plant by 90 %. For this purpose a hard coal power plant is retrofitted with a chemical absorption using different solutions of piperazine promoted potassium carbonate. The resulting power plant's efficiency losses have been accounted for. A comparison of different scenarios such as the variation of operating parameters offer an insight in detecting suitable operating conditions that will allow to minimize efficiency penalties. Simulation details are provided along with a technical and an economic analysis.

  15. Comment on "Scrutinizing the carbon cycle and CO2residence time in the atmosphere" by H. Harde

    Science.gov (United States)

    Köhler, Peter; Hauck, Judith; Völker, Christoph; Wolf-Gladrow, Dieter A.; Butzin, Martin; Halpern, Joshua B.; Rice, Ken; Zeebe, Richard E.

    2018-05-01

    Harde (2017) proposes an alternative accounting scheme for the modern carbon cycle and concludes that only 4.3% of today's atmospheric CO2 is a result of anthropogenic emissions. As we will show, this alternative scheme is too simple, is based on invalid assumptions, and does not address many of the key processes involved in the global carbon cycle that are important on the timescale of interest. Harde (2017) therefore reaches an incorrect conclusion about the role of anthropogenic CO2 emissions. Harde (2017) tries to explain changes in atmospheric CO2 concentration with a single equation, while the most simple model of the carbon cycle must at minimum contain equations of at least two reservoirs (the atmosphere and the surface ocean), which are solved simultaneously. A single equation is fundamentally at odds with basic theory and observations. In the following we will (i) clarify the difference between CO2 atmospheric residence time and adjustment time, (ii) present recently published information about anthropogenic carbon, (iii) present details about the processes that are missing in Harde (2017), (iv) briefly discuss shortcoming in Harde's generalization to paleo timescales, (v) and comment on deficiencies in some of the literature cited in Harde (2017).

  16. International co-operation in the supply of nuclear fuel and fuel cycle services

    International Nuclear Information System (INIS)

    Sievering, N.F. Jr.

    1977-01-01

    Recent changes in the United States' nuclear policy, in recognition of the increased proliferation risk, have raised questions of US intentions in international nuclear fuel and fuel-cycle service co-operation. This paper details those intentions in relation to the key elements of the new policy. In the past, the USA has been a world leader in peaceful nuclear co-operation with other nations and, mindful of the relationships between civilian nuclear technology and nuclear weapon proliferation, remains strongly committed to the Non-Proliferation Treaty, IAEA safeguards and other elements concerned with international nuclear affairs. Now, in implementing President Carter's nuclear initiatives, the USA will continue its leading role in nuclear fuel and fuel-cycle co-operation in two ways, (1) by increasing its enrichment capacity for providing international LWR fuel supplies and (2) by taking the lead in solving the problems of near and long-term spent fuel storage and disposal. Beyond these specific steps, the USA feels that the international community's past efforts in controlling the proliferation risks of nuclear power are necessary but inadequate for the future. Accordingly, the USA urges other similarly concerned nations to pause with present developments and to join in a programme of international co-operation and participation in a re-assessment of future plans which would include: (1) Mutual assessments of fuel cycles alternative to the current uranium/plutonium cycle for LWRs and breeders, seeking to lessen proliferation risks; (2) co-operative mechanisms for ensuring the ''front-end'' fuel supply including uranium resource exploration, adequate enrichment capacity, and institutional arrangements; (3) means of dealing with short-, medium- and long-term spent fuel storage needs by means of technical co-operation and assistance and possibly establishment of international storage or repository facilities; and (4) for reprocessing plants, and related fuel-cycle

  17. Integration of the tricarboxylic acid (TCA) cycle with cAMP signaling and Sfl2 pathways in the regulation of CO2 sensing and hyphal development in Candida albicans.

    Science.gov (United States)

    Tao, Li; Zhang, Yulong; Fan, Shuru; Nobile, Clarissa J; Guan, Guobo; Huang, Guanghua

    2017-08-01

    Morphological transitions and metabolic regulation are critical for the human fungal pathogen Candida albicans to adapt to the changing host environment. In this study, we generated a library of central metabolic pathway mutants in the tricarboxylic acid (TCA) cycle, and investigated the functional consequences of these gene deletions on C. albicans biology. Inactivation of the TCA cycle impairs the ability of C. albicans to utilize non-fermentable carbon sources and dramatically attenuates cell growth rates under several culture conditions. By integrating the Ras1-cAMP signaling pathway and the heat shock factor-type transcription regulator Sfl2, we found that the TCA cycle plays fundamental roles in the regulation of CO2 sensing and hyphal development. The TCA cycle and cAMP signaling pathways coordinately regulate hyphal growth through the molecular linkers ATP and CO2. Inactivation of the TCA cycle leads to lowered intracellular ATP and cAMP levels and thus affects the activation of the Ras1-regulated cAMP signaling pathway. In turn, the Ras1-cAMP signaling pathway controls the TCA cycle through both Efg1- and Sfl2-mediated transcriptional regulation in response to elevated CO2 levels. The protein kinase A (PKA) catalytic subunit Tpk1, but not Tpk2, may play a major role in this regulation. Sfl2 specifically binds to several TCA cycle and hypha-associated genes under high CO2 conditions. Global transcriptional profiling experiments indicate that Sfl2 is indeed required for the gene expression changes occurring in response to these elevated CO2 levels. Our study reveals the regulatory role of the TCA cycle in CO2 sensing and hyphal development and establishes a novel link between the TCA cycle and Ras1-cAMP signaling pathways.

  18. Integration of the tricarboxylic acid (TCA cycle with cAMP signaling and Sfl2 pathways in the regulation of CO2 sensing and hyphal development in Candida albicans.

    Directory of Open Access Journals (Sweden)

    Li Tao

    2017-08-01

    Full Text Available Morphological transitions and metabolic regulation are critical for the human fungal pathogen Candida albicans to adapt to the changing host environment. In this study, we generated a library of central metabolic pathway mutants in the tricarboxylic acid (TCA cycle, and investigated the functional consequences of these gene deletions on C. albicans biology. Inactivation of the TCA cycle impairs the ability of C. albicans to utilize non-fermentable carbon sources and dramatically attenuates cell growth rates under several culture conditions. By integrating the Ras1-cAMP signaling pathway and the heat shock factor-type transcription regulator Sfl2, we found that the TCA cycle plays fundamental roles in the regulation of CO2 sensing and hyphal development. The TCA cycle and cAMP signaling pathways coordinately regulate hyphal growth through the molecular linkers ATP and CO2. Inactivation of the TCA cycle leads to lowered intracellular ATP and cAMP levels and thus affects the activation of the Ras1-regulated cAMP signaling pathway. In turn, the Ras1-cAMP signaling pathway controls the TCA cycle through both Efg1- and Sfl2-mediated transcriptional regulation in response to elevated CO2 levels. The protein kinase A (PKA catalytic subunit Tpk1, but not Tpk2, may play a major role in this regulation. Sfl2 specifically binds to several TCA cycle and hypha-associated genes under high CO2 conditions. Global transcriptional profiling experiments indicate that Sfl2 is indeed required for the gene expression changes occurring in response to these elevated CO2 levels. Our study reveals the regulatory role of the TCA cycle in CO2 sensing and hyphal development and establishes a novel link between the TCA cycle and Ras1-cAMP signaling pathways.

  19. Exergy, exergoeconomic and environmental analyses and evolutionary algorithm based multi-objective optimization of combined cycle power plants

    International Nuclear Information System (INIS)

    Ahmadi, Pouria; Dincer, Ibrahim; Rosen, Marc A.

    2011-01-01

    A comprehensive exergy, exergoeconomic and environmental impact analysis and optimization is reported of several combined cycle power plants (CCPPs). In the first part, thermodynamic analyses based on energy and exergy of the CCPPs are performed, and the effect of supplementary firing on the natural gas-fired CCPP is investigated. The latter step includes the effect of supplementary firing on the performance of bottoming cycle and CO 2 emissions, and utilizes the first and second laws of thermodynamics. In the second part, a multi-objective optimization is performed to determine the 'best' design parameters, accounting for exergetic, economic and environmental factors. The optimization considers three objective functions: CCPP exergy efficiency, total cost rate of the system products and CO 2 emissions of the overall plant. The environmental impact in terms of CO 2 emissions is integrated with the exergoeconomic objective function as a new objective function. The results of both exergy and exergoeconomic analyses show that the largest exergy destructions occur in the CCPP combustion chamber, and that increasing the gas turbine inlet temperature decreases the CCPP cost of exergy destruction. The optimization results demonstrates that CO 2 emissions are reduced by selecting the best components and using a low fuel injection rate into the combustion chamber. -- Highlights: → Comprehensive thermodynamic modeling of a combined cycle power plant. → Exergy, economic and environmental analyses of the system. → Investigation of the role of multiobjective exergoenvironmental optimization as a tool for more environmentally-benign design.

  20. Preliminary life-cycle assessment of biomass-derived refinery feedstocks for reducing CO2 emissions

    International Nuclear Information System (INIS)

    Marano, J.J.; Rogers, S.; Spath, P.L.; Mann, M.K.

    1995-01-01

    The US by ratification of the United Nations Framework Convention on Climate Change has pledged to emit no higher levels of greenhouse gases in the year 2000 than it did in 1990. Biomass-derived products have been touted as a possible solution to the potential problem of global warming. However, past studies related to the production of liquid fuels, chemicals, gaseous products, or electricity from biomass, have only considered the economics of producing these commodities. The environmental benefits have not been fully quantified and factored into these estimates until recently. Evaluating the environmental impact of various biomass systems has begun using life-cycle assessment. A refinery Linear Programming model previously developed has been modified to examine the effects of CO 2 -capping on the US refining industry and the transportation sector as a whole. By incorporating the results of a CO 2 emissions inventory into the model, the economic impact of emissions reduction strategies can be estimated. Thus, the degree to which global warming can be solved by supplementing fossil fuels with biomass-derived products can be measured, allowing research and development to be concentrated on the most environmentally and economically attractive technology mix. Biomass gasification to produce four different refinery feedstocks was considered in this analysis. These biomass-derived products include power, fuel gas, hydrogen for refinery processing, and Fischer-Tropsch liquids for upgrading and blending into finished transportation fuels

  1. Comparative 4-E analysis of a bottoming pure NH3 and NH3-H2O mixture based power cycle for condenser waste heat recovery

    Science.gov (United States)

    Khankari, Goutam; Karmakar, Sujit

    2017-06-01

    This paper proposes a comparative performance analysis based on 4-E (Energy, Exergy, Environment, and Economic) of a bottoming pure Ammonia (NH3) based Organic Rankine Cycle (ORC) and Ammonia-water (NH3-H2O) based Kalina Cycle System 11(KCS 11) for additional power generation through condenser waste heat recovery integrated with a conventional 500MWe Subcritical coal-fired thermal power plant. A typical high-ash Indian coal is used for the analysis. The flow-sheet computer programme `Cycle Tempo' is used to simulate both the cycles for thermodynamic performance analysis at different plant operating conditions. Thermodynamic analysis is done by varying different NH3 mass fraction in KCS11 and at different turbine inlet pressure in both ORC and KCS11. Results show that the optimum operating pressure of ORC and KCS11 with NH3 mass fraction of 0.90 are about 15 bar and 11.70 bar, respectively and more than 14 bar of operating pressure, the plant performance of ORC integrated power plant is higher than the KCS11 integrated power plant and the result is observed reverse below this pressure. The energy and exergy efficiencies of ORC cycle are higher than the KCS11 by about 0.903 % point and 16.605 % points, respectively under similar saturation vapour temperature at turbine inlet for both the cycles. Similarly, plant energy and exergy efficiencies of ORC based combined cycle power plant are increased by 0.460 % point and 0.420 % point, respectively over KCS11 based combined cycle power plant. Moreover, the reduction of CO2 emission in ORC based combined cycle is about 3.23 t/hr which is about 1.5 times higher than the KCS11 based combined cycle power plant. Exergy destruction of the evaporator in ORC decreases with increase in operating pressure due to decrease in temperature difference of heat exchanging fluids. Exergy destruction rate in the evaporator of ORC is higher than KCS11 when the operating pressure of ORC reduces below 14 bar. This happens due to variable

  2. Integrated operation and management system for a 700MW combined cycle power plant

    Energy Technology Data Exchange (ETDEWEB)

    Shiroumaru, I. (Yanai Power Plant Construction Office, Chugoku Electric Power Co., Inc., 1575-5 Yanai-Miyamoto-Shiohama, Yanai-shi, Yamaguchi-ken (JP)); Iwamiya, T. (Omika Works, Hitachi, Ltd., 5-2-1 Omika-cho, Hitachi-shi, Ibaraki-ken (JP)); Fukai, M. (Hitachi Works, Hitachi, Ltd., 3-1-1 Saiwai-cho, Hitachi-shi, Ibaraki-ken (JP))

    1992-03-01

    Yanai Power Plant of the Chugoku Electric Power Co., Inc. (Yamaguchi Pref., Japan) is in the process of constructing a 1400MW state-of-the-art combined cycle power plant. The first phase, a 350MW power plant, started operation on a commercial basis in November, 1990. This power plant has achieved high efficiency and high operability, major features of a combined cycle power plant. The integrated operation and management system of the power plant takes care of operation, maintenance, control of general business, etc., and was built using the latest computer and digital control and communication technologies. This paper reports that it is expected that this system will enhance efficient operation and management for the power plant.

  3. Enhanced cycling stability of NiCo2S4@NiO core-shell nanowire arrays for all-solid-state asymmetric supercapacitors

    Science.gov (United States)

    Huang, Yuanyuan; Shi, Tielin; Jiang, Shulan; Cheng, Siyi; Tao, Xiangxu; Zhong, Yan; Liao, Guanglan; Tang, Zirong

    2016-12-01

    As a new class of pseudocapacitive material, metal sulfides possess high electrochemical performance. However, their cycling performance as conventional electrodes is rather poor for practical applications. In this article, we report an original composite electrode based on NiCo2S4@NiO core-shell nanowire arrays (NWAs) with enhanced cycling stability. This three-dimensional electrode also has a high specific capacitance of 12.2 F cm-2 at the current density of 1 mA cm-2 and excellent cycling stability (about 89% retention after 10,000 cycles). Moreover, an all-solid-state asymmetric supercapacitor (ASC) device has been assembled with NiCo2S4@NiO NWAs as the positive electrode and active carbon (AC) as the negative electrode, delivering a high energy density of 30.38 W h kg-1 at 0.288 KW kg-1 and good cycling stability (about 109% retention after 5000 cycles). The results show that NiCo2S4@NiO NWAs are promising for high-performance supercapacitors with stable cycling based on the unique core-shell structure and well-designed combinations.

  4. Combined cycle versus one thousand diesel power plants: pollutant emissions, ecological efficiency and economic analysis

    International Nuclear Information System (INIS)

    Silveira, Jose Luz; de Carvalho, Joao Andrade; de Castro Villela, Iraides Aparecida

    2007-01-01

    The increase in the use of natural gas in Brazil has stimulated public and private sectors to analyse the possibility of using combined cycle systems for generation of electrical energy. Gas turbine combined cycle power plants are becoming increasingly common due to their high efficiency, short lead times, and ability to meet environmental standards. Power is produced in a generator linked directly to the gas turbine. The gas turbine exhaust gases are sent to a heat recovery steam generator to produce superheated steam that can be used in a steam turbine to produce additional power. In this paper a comparative study between a 1000 MW combined cycle power plant and 1000kW diesel power plant is presented. In first step, the energetic situation in Brazil, the needs of the electric sector modification and the needs of demand management and integrated means planning are clarified. In another step the characteristics of large and small thermoelectric power plants that use natural gas and diesel fuel, respectively, are presented. The ecological efficiency levels of each type of power plant is considered in the discussion, presenting the emissions of particulate material, sulphur dioxide (SO 2 ), carbon dioxide (CO 2 ) and nitrogen oxides (NO x ). (author)

  5. Improvement of the cycling performance of LiCoO2 with assistance of cross-linked PAN for lithium ion batteries

    International Nuclear Information System (INIS)

    Yang, Xinhe; Shen, Lanyao; Wu, Bin; Zuo, Zicheng; Mu, Daobin; Wu, Borong; Zhou, Henghui

    2015-01-01

    Highlights: • Cross-linked PAN coating was prepared without damaging the surface of LiCoO 2 . • The coating layer owns good electronic conductivity and mechanical strength. • The cross-linked PAN coating layer is more sufficient than Al 2 O 3 coating. • It shows much improved cyclability than that of bare and Al 2 O 3 coated LiCoO 2 . - Abstract: LiCoO 2 has been widely used in lithium ion batteries for digital electronic products. However, the limited cycling performance under high cut-off voltage hinders its commercial application. Many metal oxides and/or phosphorus coating have been reported to improve the cycling performance of LiCoO 2 . In this paper, we report on cross-linked PAN coated LiCoO 2 composite as a cathode material for lithium ion batteries. The coating layer was obtained by intermolecular crosslinking of PAN polymer chain by heat treatment at high temperature in air. The air heating process avoids the possible damage arising from the carbon thermal reduction to the surface structure of LiCoO 2 . Electrochemical test indicates that the LiCoO 2 with the cross-linked PAN coating layer shows much improved cycle performance compared with that of bare and Al 2 O 3 coated LiCoO 2 . These findings might also open new avenues to explore polymer coating for other cathode materials of lithium ion batteries

  6. CO{sub 2} emission costs and Gas/Coal competition for power production; Prezzi delle emissioni di CO{sub 2} e competivita' gas/carbone per la produzione termoelettrica

    Energy Technology Data Exchange (ETDEWEB)

    Santi, Federico [La Sapienza Univ., Roma (Italy). Dipartimento di Ingegneria Nucleare e Conversioni dell' Energia

    2005-05-01

    This paper demonstrates how a CO{sub 2} emission reduction programme can change the competition between the two power production technologies which will probably dominate the future of the Italian power industry: the coal fired USC steam power plant and the natural gas fired CCGT power plant. An economic value of the CO{sub 2} emission is calculated, in order to make the short-run-marginal-cost (or the long-run-marginal-cost). equal for both technologies, under a CO{sub 2} emission trading scheme and following a single-plant specific CO{sub 2} emission homogenizing approach. [Italian] Si dimostra come un programma teso alla riduzione delle emissioni di CO{sub 2} possa mutare la competivita' tra le due tecnologie per la produzione termoelettrica che saranno dominanti nel prossimo futuro in Italia: le centrali a carbone USC e le centrali CCGT a gas naturale. Si calcola il prezzo delle emissioni di CO{sub 2} per valutare il costo marginale di breve periodo (o il costo marginale di lungo periodo) per entrambe le tecnologie, avvalendosi di un programma di emission trading e utilizzando un approccio di omogeneizzazione delle emissioni di CO{sub 2} specifiche di ogni impianto.

  7. Determination of a CO sub 2 rating formula for fossil-fired, electricity-generating power plants. Zur Festlegung einer CO sub 2 -Steuerformel fuer fossil-befeuerte, stromerzeugende Kraftwerke

    Energy Technology Data Exchange (ETDEWEB)

    Seifritz, W [Stuttgart Univ. (Germany). Inst. fuer Energiewirtschaft und Rationelle Energieanwendung

    1991-12-01

    Dr. Martin Proske was right in Ref (1) to point to the fact that a CO{sub 2}-tax has to take into account the quality of the secondary energy carrier, too. In the opinion of the author, however, the tax-formula of M. Proske has still to be modified if CO{sub 2}-free fossil power stations were introduced. Failing this, the development of CO{sub 2}-free power stations with the necessary removal and disposal of CO{sub 2} would be not attractive although this future type of a power station could substantially contribute to the climate-neutrality of fossil fuels. A corresponding modification of the tax-formula is proposed. (orig.).

  8. Nuclear design report for Ulchin nuclear power plant unit 2 cycle 5

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Ha; Park, Yong Soo; Cho, Byeong Ho; Zee, Sung Kyun; Lee, Sang Keun; Ahn, Dawk Hwan [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1993-09-01

    This report presents nuclear design calculations for cycle 5 of Ulchin unit it 2. Information is given on fuel loading, power density distributions, reactivity coefficients, control rod worths and operational limits. In addition, the report contains all necessary data for the startup tests including predicted values for the comparison with the measured data. The reload consists of 48 KOFA`s enriched by nominally 3.50 w/o U{sub 235}. Among the KOFA`s, 20 fuel assemblies contain gadolinia rods. The fuel assemblies in the core are arranged in a low leakage loading pattern. The cycle length of cycle 5 amounts to 293 EFPD corresponding to a cycle burnup of 11780 MWD/MTU. (Author) 8 refs., 55 figs., 16 tabs.

  9. Greenhouse effect and CO2 emissions. 3. rev. and enlarged ed.

    International Nuclear Information System (INIS)

    Kuehr, W.

    1990-01-01

    The brochure is to prove that nuclear energy does not present a technology which would avoid the greenhouse effect. It is true that nuclear power plants do not produce CO 2 , but the production cycle includes ore mines, uranium enrichement, etc. where energy reguirements are met by fossil fuels, and this is where nuclear power plants pruduce CO 2 indirectly. Environmental and climate hazards can be influenced by economic and political decisions. It is important to reduce consumption, to promote renewable energy sources, and to replace nuclear as well as fossil fuels. (orig./HSCH) [de

  10. Modelling the power conversion unit of a generic nuclear fusion plant, with a dual coolant blanket and a supercritical CO2 power cycle, by means of RELAP5-3D

    Energy Technology Data Exchange (ETDEWEB)

    Batet, L.

    2015-07-01

    In the framework of the Spanish fusion program TECNO-FUS, a dual coolant blanket design was proposed for DEMO. A generic power conversion system (supercritical recompression CO2 cycle) based on this proposal has been simulated using RELAP5-3D, a multipurpose system thermal-hydraulic code developed by the Idaho National Laboratory (USA). The code allows the dynamic simulation of thermal-hydraulic systems, including the control features. A model has been set up by assembling the available RELAP5-3D components: pipe, branch, pump, compressor, turbine, etc. Thermal fluxes between fluids in heat exchangers are simulated by means of heat structures, which are used as well to simulate the heating from plasma. A number of control features have been designed for the simulated plant, and their parameters have been adjusted. The code is then able to simulate robustly the dynamics of the system with a few boundary conditions. This paper exemplifies the usefulness of the code and model to understand the behavior of the plant and to perform sensitivity analyses of the control parameters or other design features. (Author)

  11. Effectiveness of US state policies in reducing CO2 emissions from power plants

    Science.gov (United States)

    Grant, Don; Bergstrand, Kelly; Running, Katrina

    2014-11-01

    President Obama's landmark initiative to reduce the CO2 emissions of existing power plants, the nation's largest source of greenhouse gas (GHG) pollutants, depends heavily on states and their ability to devise policies that meet the goals set by the Environmental Protection Agency (EPA). Under the EPA's proposed Clean Power Plan, states will be responsible for cutting power plants' carbon pollution 30% from 2005 levels by 2030. States have already adopted several policies to reduce the electricity sector's climate impact. Some of these policies focus on reducing power plants' CO2 emissions, and others address this outcome in a more roundabout fashion by encouraging energy efficiency and renewable energy. However, it remains unclear which, if any, of these direct and indirect strategies actually mitigate plants' emissions because scholars have yet to test their effects using plant-level emission data. Here we use a newly released data source to determine whether states' policies significantly shape individual power plants' CO2 emissions. Findings reveal that certain types of direct strategy (emission caps and GHG targets) and indirect ones (public benefit funds and electric decoupling) lower plants' emissions and thus are viable building blocks of a federal climate regime.

  12. The economics of reducing CO2 emissions by solar thermal power plants

    International Nuclear Information System (INIS)

    Brakmann, G.

    1993-01-01

    The necessity to reduce CO 2 -emissions on a global scale is being recognized by scientists and politicians. If no scientific proof of a climate catastrophe due to CO 2 -emissions can be established, it would nevertheless be prudent to implement a form of global survival insurance policy, the premium of which is the required effort to reduce CO 2 -emissions. The implementation of such a policy without a considerable reduction in the living standard requires the replacement of fossil fuels by capital and/or know-how. It should be performed in the most economical manner. This leads to the replacement of the classical ''least cost power expansion strategy'' by the ''least cost power expansion/pollution limiting strategy''. Thereby projects have to compete no longer exclusively on low cost of energy production but on low cost of pollution reduction as well. (Author)

  13. The carbonate-silicate cycle and CO2/climate feedbacks on tidally locked terrestrial planets.

    Science.gov (United States)

    Edson, Adam R; Kasting, James F; Pollard, David; Lee, Sukyoung; Bannon, Peter R

    2012-06-01

    Atmospheric gaseous constituents play an important role in determining the surface temperatures and habitability of a planet. Using a global climate model and a parameterization of the carbonate-silicate cycle, we explored the effect of the location of the substellar point on the atmospheric CO(2) concentration and temperatures of a tidally locked terrestrial planet, using the present Earth continental distribution as an example. We found that the substellar point's location relative to the continents is an important factor in determining weathering and the equilibrium atmospheric CO(2) level. Placing the substellar point over the Atlantic Ocean results in an atmospheric CO(2) concentration of 7 ppmv and a global mean surface air temperature of 247 K, making ∼30% of the planet's surface habitable, whereas placing it over the Pacific Ocean results in a CO(2) concentration of 60,311 ppmv and a global temperature of 282 K, making ∼55% of the surface habitable.

  14. Reload safety evaluation report for kori nuclear power plant unit 2 cycle 9

    International Nuclear Information System (INIS)

    Cho, Beom Jin; Kim, Si Yong; Kim, Oh Hwan; Nam, Kee Il; Um, Gil Sup; Ban, Chang Hwan; Choi, Dong Uk; Yoon, Kyung Ho

    1992-04-01

    The Kori Nuclear Power Plant Unit 2 (Kori-2) is anticipated to be refuelled with 16x16 Korean Fuel Assemblies (KOFA), which are based on the KAERI design starting from Cycle 8. This report presents a reload safety evaluation for Kori-2, Cycle 9 and demonstrates that the reactor core being composed of various fuel assembly types as described below will not adversely affect the safety of the public and the plant. The evaluation of Kori-2, Cycle 9 was accomplished utilizing the methodology described in 'Reload Transition Safety Report for KORI 2' (Ref. /1-1/). The reload core for Kori-2, Cycle 9 is entirely comprised of 16x16 KOFA. In the Kori-2 licensing documentation to KEPCO the reference safety evaluation was provided for the operation of a reactor core fully loaded with KOFA as well as associated proposed changes to the Kori-2 Technical Specifications. The reload for Kori-2, Cycle 9 also introduces UO 2 /Gd 2 O 3 containing fuel rods. The use of fuel rods with Gd 2 O 3 poisoning of the fuel has been approved as a part of the above mentioned licensing documentation. All of the accidents comprising the licensing bases which could potentially be affected by the fuel reload have been reviewed for the Cycle 9 core design described herein. (Author)

  15. Superior Cycle Stability Performance of Quasi-Cuboidal CoV2O6 Microstructures as Electrode Material for Supercapacitors.

    Science.gov (United States)

    Wang, Yucheng; Chai, Hui; Dong, Hong; Xu, Jiayu; Jia, Dianzeng; Zhou, Wanyong

    2016-10-12

    In this study, a rapid, facile, and environment-friendly microwave-assisted method followed by annealing for synthesizing the quasi-cuboidal CoV 2 O 6 is developed. The as-prepared samples manifest high supercapacitor properties with a specific capacitance of 223 F g -1 , good rate capability, and superior cycle stability, retaining 123.3% capacitance when the number of cycles reaches 15,000 after determined by electrochemical tests. More importantly, the quasi-cuboidal CoV 2 O 6 for the first time is introduced into the supercapacitor as a kind of electrode material. The superior electrochemical performance of the quasi-cuboidal CoV 2 O 6 will render the metal vanadium oxides as new and attractive active material for promising application in supercapacitors.

  16. Incorporation of Co into MoS2/graphene nanocomposites: One effective way to enhance the cycling stability of Li/Na storage

    Science.gov (United States)

    Li, Xiaomin; Feng, Zhenxing; Zai, Jiantao; Ma, Zi-Feng; Qian, Xuefeng

    2018-01-01

    Layered transition metal dichalcogenides are promising as lithium and/or sodium storage materials for lithium and sodium (Li/Na) ion batteries. However they always exhibit limited rate capability and long-term cycling stability, due to the fact that their 2D structures are easily restacking and agglomeration during cycling process and further result poor electrochemical reversibility. Herein, hierarchical Co1/3Mo2/3S2/graphene nanocomposites without CoSx and MoS2 impurities have been synthesized via one-pot solvothermal process. The incorporation of Co into MoS2 at atomic level can not only give rise to thinner and smaller nanosheets in the nanocomposites than MoS2/graphene nanocomposites, but also significantly decrease the size of in-situ formed MoS2/CoSx nanoparticles during electrochemical conversion process, which can greatly promoting the ion diffusion and suppressing the aggregation of active materials. Furthermore, the conductivity of Co1/3Mo2/3S2/graphene nanocomposites can be enhanced from 0.46 S m-1 (MoS2/graphene) to 1.39 S m-1via changing the semiconducting MoS2 to metallic Co1/3Mo2/3S2. The simultaneously optimized electron conductivity and ions diffusion dynamics of Co1/3Mo2/3S2/graphene nanocomposites can effectively improve the reversibility of electrochemical conversion reactions. A capacity of 940 mAh g-1 and 529 mAh g-1 can be maintained at 3200th cycle (2 A g-1) in lithium-ion batteries and 200th cycle (1 A g-1) in sodium-ion batteries, respectively.

  17. Passive Decay Heat Removal System Options for S-CO2 Cooled Micro Modular Reactor

    International Nuclear Information System (INIS)

    Moon, Jangsik; Jeong, Yong Hoon; Lee, Jeong Ik

    2014-01-01

    To achieve modularization of whole reactor system, Micro Modular Reactor (MMR) which has been being developed in KAIST took S-CO 2 Brayton power cycle. The S-CO 2 power cycle is suitable for SMR due to high cycle efficiency, simple layout, small turbine and small heat exchanger. These characteristics of S-CO 2 power cycle enable modular reactor system and make reduced system size. The reduced size and modular system motived MMR to have mobility by large trailer. Due to minimized on-site construction by modular system, MMR can be deployed in any electricity demand, even in isolated area. To achieve the objective, fully passive safety systems of MMR were designed to have high reliability when any offsite power is unavailable. In this research, the basic concept about MMR and Passive Decay Heat Removal (PDHR) system options for MMR are presented. LOCA, LOFA, LOHS and SBO are considered as DBAs of MMR. To cope with the DBAs, passive decay heat removal system is designed. Water cooled PDHR system shows simple layout, but has CCF with reactor systems and cannot cover all DBAs. On the other hand, air cooled PDHR system with two-phase closed thermosyphon shows high reliability due to minimized CCF and is able to cope with all DBAs. Therefore, the PDHR system of MMR will follows the air-cooled PDHR system and the air cooled system will be explored

  18. The global pyrogenic carbon cycle and its impact on the level of atmospheric CO2 over past and future centuries.

    Science.gov (United States)

    Landry, Jean-Sébastien; Matthews, H Damon

    2017-08-01

    The incomplete combustion of vegetation and dead organic matter by landscape fires creates recalcitrant pyrogenic carbon (PyC), which could be consequential for the global carbon budget if changes in fire regime, climate, and atmospheric CO 2 were to substantially affect gains and losses of PyC on land and in oceans. Here, we included global PyC cycling in a coupled climate-carbon model to assess the role of PyC in historical and future simulations, accounting for uncertainties through five sets of parameter estimates. We obtained year-2000 global stocks of (Central estimate, likely uncertainty range in parentheses) 86 (11-154), 47 (2-64), and 1129 (90-5892) Pg C for terrestrial residual PyC (RPyC), marine dissolved PyC, and marine particulate PyC, respectively. PyC cycling decreased atmospheric CO 2 only slightly between 1751 and 2000 (by 0.8 Pg C for the Central estimate) as PyC-related fluxes changed little over the period. For 2000 to 2300, we combined Representative Concentration Pathways (RCPs) 4.5 and 8.5 with stable or continuously increasing future fire frequencies. For the increasing future fire regime, the production of new RPyC generally outpaced the warming-induced accelerated loss of existing RPyC, so that PyC cycling decreased atmospheric CO 2 between 2000 and 2300 for most estimates (by 4-8 Pg C for Central). For the stable fire regime, however, PyC cycling usually increased atmospheric CO 2 (by 1-9 Pg C for Central), and only the most extreme choice of parameters maximizing PyC production and minimizing PyC decomposition led to atmospheric CO 2 decreases under RCPs 4.5 and 8.5 (by 5-8 Pg C). Our results suggest that PyC cycling will likely reduce the future increase in atmospheric CO 2 if landscape fires become much more frequent; however, in the absence of a substantial increase in fire frequency, PyC cycling might contribute to, rather than mitigate, the future increase in atmospheric CO 2 . © 2016 John Wiley & Sons Ltd.

  19. Research on the general analytical method of fossil fuel cycle from a viewpoint of the global environment. 3; Chikyu kankyo kara mita sogoteki kaseki nenryo cycle bunseki hyoka shuho no chosa. 3

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    The general analysis/assessment method of a fossil fuel cycle was studied. Seven kinds of power generation plants such as LNG cycle and coal cycle ones, and four kinds of transport and treatment systems of recovered CO2 such as ocean and underground systems were studied as case studies on life cycle analysis. As data necessary for life cycle analysis, the database was constructed which stores the facilities and operational energy required for a total energy system from mining of fossil fuel to treatment of recovered CO2, and the quantity of environmental waste such as CO2 emission. As a result, the decrease rate of energy balance defined as ratio of input energy to power plant output was estimated to be 14-43% and 20-60% in LNG cycle and coal cycle, respectively. Even if the recovery rate of CO2 in power plants reached 80-90%, reduction of total CO2 emission was limited to only 20-40% because of CO2 emission during mining, liquefaction and transport of fuel. 168 refs., 48 figs., 102 tabs.

  20. Geothermal life cycle assessment - part 3

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, J. L. [Argonne National Lab. (ANL), Argonne, IL (United States); Frank, E. D. [Argonne National Lab. (ANL), Argonne, IL (United States); Han, J. [Argonne National Lab. (ANL), Argonne, IL (United States); Elgowainy, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, M. Q. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2013-11-01

    A set of key issues pertaining to the environmental performance of geothermal electric power have been addressed. They include: 1) greenhouse gas emissions (GHG) from geothermal facilities, 2) the use of supercritical carbon dioxide (scCO2) as a geofluid for enhanced geothermal systems (EGS), 3) quantifying the impact of well field exploration on the life cycle of geothermal power, and finally 4) criteria pollutant emissions for geothermal and other electric power generation. A GHG emission rate (g/kWh) distribution as function of cumulative running capacity for California has been developed based on California and U. S. government data. The distribution is similar to a global distribution for compared geothermal technologies. A model has been developed to estimate life cycle energy of and CO2 emissions from a coupled pair of coal and EGS plants, the latter of which is powered by scCO2 captured from coal plant side. Depending on the CO2 capture rate on the coal side and the CO2 consumption rate on the EGS side, significant reductions in GHG emissions were computed when the combined system is compared to its conventional coal counterpart. In effect, EGS CO2 consumption acts as a sequestration mechanism for the coal plant. The effects CO2 emissions from the coupled system, prompt on the coal side and reservoir leakage on the EGS side, were considered as well as the subsequent decline of these emissions after entering the atmosphere over a time frame of 100 years. A model was also developed to provide better estimates of the impact of well field exploration on the life cycle performance of geothermal power production. The new estimates increase the overall life cycle metrics for the geothermal systems over those previously estimated. Finally, the GREET model has been updated to include the most recent criteria pollutant emissions for a range of renewable (including geothermal) and other power

  1. Hybrid Composite Ni(OH)(2)@NiCo2O4 Grown on Carbon Fiber Paper for High-Performance Supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Huang, L; Chen, DC; Ding, Y; Wang, ZL; Zeng, ZZ; Liu, ML

    2013-11-13

    We have successfully fabricated and tested the electrochemical performance of supercapacitor electrodes consisting of Ni(OH)(2) nanosheets coated on NiCo2O4 nanosheets grown on carbon fiber paper (CFP) current collectors. When the NiCo2O4 nanosheets are replaced by Co3O4 nanosheets, however, the energy and power density as well as the rate capability of the electrodes are significantly reduced, most likely due to the lower conductivity of Co3O4 than that of NiCo2O4. The 3D hybrid composite Ni(OH)(2)/ NiCo2O4/CFP electrodes demonstrate a high areal capacitance of 5.2 F/cm(2) at a cycling current density of 2 rnA/cm(2), with a capacitance retention of 79% as the cycling current density was increased from 2 to 50 mA/cm(2). The remarkable performance of these hybrid composite electrodes implies that supercapacitors based on them have potential for many practical applications.

  2. Hybrid composite Ni(OH)2@NiCo2O4 grown on carbon fiber paper for high-performance supercapacitors.

    Science.gov (United States)

    Huang, Liang; Chen, Dongchang; Ding, Yong; Wang, Zhong Lin; Zeng, Zhengzhi; Liu, Meilin

    2013-11-13

    We have successfully fabricated and tested the electrochemical performance of supercapacitor electrodes consisting of Ni(OH)2 nanosheets coated on NiCo2O4 nanosheets grown on carbon fiber paper (CFP) current collectors. When the NiCo2O4 nanosheets are replaced by Co3O4 nanosheets, however, the energy and power density as well as the rate capability of the electrodes are significantly reduced, most likely due to the lower conductivity of Co3O4 than that of NiCo2O4. The 3D hybrid composite Ni(OH)2/NiCo2O4/CFP electrodes demonstrate a high areal capacitance of 5.2 F/cm(2) at a cycling current density of 2 mA/cm(2), with a capacitance retention of 79% as the cycling current density was increased from 2 to 50 mA/cm(2). The remarkable performance of these hybrid composite electrodes implies that supercapacitors based on them have potential for many practical applications.

  3. Membrane Process to Capture CO{sub 2} from Coal-Fired Power Plant Flue Gas

    Energy Technology Data Exchange (ETDEWEB)

    Merkel, Tim; Wei, Xiaotong; Firat, Bilgen; He, Jenny; Amo, Karl; Pande, Saurabh; Baker, Richard; Wijmans, Hans; Bhown, Abhoyjit

    2012-03-31

    This final report describes work conducted for the U.S. Department of Energy National Energy Technology Laboratory (DOE NETL) on development of an efficient membrane process to capture carbon dioxide (CO{sub 2}) from power plant flue gas (award number DE-NT0005312). The primary goal of this research program was to demonstrate, in a field test, the ability of a membrane process to capture up to 90% of CO{sub 2} in coal-fired flue gas, and to evaluate the potential of a full-scale version of the process to perform this separation with less than a 35% increase in the levelized cost of electricity (LCOE). Membrane Technology and Research (MTR) conducted this project in collaboration with Arizona Public Services (APS), who hosted a membrane field test at their Cholla coal-fired power plant, and the Electric Power Research Institute (EPRI) and WorleyParsons (WP), who performed a comparative cost analysis of the proposed membrane CO{sub 2} capture process. The work conducted for this project included membrane and module development, slipstream testing of commercial-sized modules with natural gas and coal-fired flue gas, process design optimization, and a detailed systems and cost analysis of a membrane retrofit to a commercial power plant. The Polaris? membrane developed over a number of years by MTR represents a step-change improvement in CO{sub 2} permeance compared to previous commercial CO{sub 2}-selective membranes. During this project, membrane optimization work resulted in a further doubling of the CO{sub 2} permeance of Polaris membrane while maintaining the CO{sub 2}/N{sub 2} selectivity. This is an important accomplishment because increased CO{sub 2} permeance directly impacts the membrane skid cost and footprint: a doubling of CO{sub 2} permeance halves the skid cost and footprint. In addition to providing high CO{sub 2} permeance, flue gas CO{sub 2} capture membranes must be stable in the presence of contaminants including SO{sub 2}. Laboratory tests showed no

  4. Supercritical Carbon Dioxide Brayton Cycle Energy Conversion System

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Jae Eun; Kim, S. O.; Seong, S. H.; Eoh, J. H.; Lee, T. H.; Choi, S. K.; Han, J. W.; Bae, S. W

    2007-12-15

    This report contains the description of the S-CO{sub 2} Brayton cycle coupled to KALIMER-600 as an alternative energy conversion system. For system development, a computer code was developed to calculate heat balance of 100% power operation condition. Based on the computer code, the S-CO{sub 2} Brayton cycle energy conversion system was constructed for the KALIMER-600. Using the developed turbomachinery models, the off-design characteristics and the sensitivities of the S-CO{sub 2} turbomachinery were investigated. For the development of PCHE models, a one-dimensional analysis computer code was developed to evaluate the performance of the PCHE. Possible control schemes for power control in the KALIMER-600 S-CO{sub 2} Brayton cycle were investigated by using the MARS code. Simple power reduction and recovery event was selected and analyzed for the transient calculation. For the evaluation of Na/CO{sub 2} boundary failure event, a computer was developed to simulate the complex thermodynamic behaviors coupled with the chemical reaction between liquid sodium and CO{sub 2} gas. The long term behavior of a Na/CO{sub 2} boundary failure event and its consequences which lead to a system pressure transient were evaluated.

  5. Supercritical Carbon Dioxide Brayton Cycle Energy Conversion System

    International Nuclear Information System (INIS)

    Cha, Jae Eun; Kim, S. O.; Seong, S. H.; Eoh, J. H.; Lee, T. H.; Choi, S. K.; Han, J. W.; Bae, S. W.

    2007-12-01

    This report contains the description of the S-CO 2 Brayton cycle coupled to KALIMER-600 as an alternative energy conversion system. For system development, a computer code was developed to calculate heat balance of 100% power operation condition. Based on the computer code, the S-CO 2 Brayton cycle energy conversion system was constructed for the KALIMER-600. Using the developed turbomachinery models, the off-design characteristics and the sensitivities of the S-CO 2 turbomachinery were investigated. For the development of PCHE models, a one-dimensional analysis computer code was developed to evaluate the performance of the PCHE. Possible control schemes for power control in the KALIMER-600 S-CO 2 Brayton cycle were investigated by using the MARS code. Simple power reduction and recovery event was selected and analyzed for the transient calculation. For the evaluation of Na/CO 2 boundary failure event, a computer was developed to simulate the complex thermodynamic behaviors coupled with the chemical reaction between liquid sodium and CO 2 gas. The long term behavior of a Na/CO 2 boundary failure event and its consequences which lead to a system pressure transient were evaluated

  6. Numerical simulation and experimental validation of internal heat exchanger influence on CO{sub 2} trans-critical cycle performance

    Energy Technology Data Exchange (ETDEWEB)

    Rigola, Joaquim; Ablanque, Nicolas; Perez-Segarra, Carlos D.; Oliva, Assensi [Centre Tecnologic de Transferencia de Calor (CTTC), Universitat Politecnica de Catalunya (UPC), ETSEIAT, C. Colom 11, 08222 Terrassa (Barcelona) (Spain)

    2010-06-15

    The present paper is a numerical and experimental comparative study of the whole vapour compression refrigerating cycle in general, and reciprocating compressors in particular, with the aim of showing the possibilities that CO{sub 2} offers for commercial refrigeration, considering a single-stage trans-critical cycle using semi-hermetic reciprocating compressors under small cooling capacity systems. The present work is focussed on the influence of using an internal heat exchanger (IHX) in order to improve the cycle performance under real working conditions. In order to validate the numerical results, an experimental unit specially designed and built to analyze trans-critical refrigerating equipments considering IHX has been built. Both numerical results and experimental data show reasonable good agreement, while the comparative global values conclude the improvement of cooling capacity and COP when IHX is considered in the CO{sub 2} trans-critical cycle. (author)

  7. Changes in CO2 during Ocean Anoxic Event 1d indicate similarities to other carbon cycle perturbations

    Science.gov (United States)

    Richey, Jon D.; Upchurch, Garland R.; Montañez, Isabel P.; Lomax, Barry H.; Suarez, Marina B.; Crout, Neil M. J.; Joeckel, R. M.; Ludvigson, Greg A.; Smith, Jon J.

    2018-06-01

    Past greenhouse intervals of the Mesozoic were repeatedly punctuated by Ocean Anoxic Events (OAEs), major perturbations to the global carbon cycle and abrupt climate changes that may serve as relevant analogs for Earth's greenhouse gas-forced climate future. The key to better understanding these transient climate disruptions and possible CO2-forced tipping-points resides in high-resolution, precise, and accurate estimates of atmospheric CO2 for individual OAEs. Here we present a high-temporal resolution, multi-proxy pCO2 reconstruction for the onset of mid-Cretaceous (Albian-Cenomanian Boundary) OAE1d. Coupling of pCO2 estimates with carbon isotopic compositions (δ13C) of charcoal, vitrain, and cuticle from the Rose Creek Pit (RCP), Nebraska, reveals complex phasing, including a lag between the well-documented negative δ13C excursion defining the onset of OAE1d and the CO2 increase. This lag indicates that increased CO2 or other C-based greenhouse gases may not have been the primary cause of the negative excursion. Our study reveals a pCO2 increase within the interval of the negative δ13C excursion, reaching a maximum of up to ∼840 ppm (95% confidence interval -307 ppm/+167 ppm) toward its end. The reconstructed magnitude of CO2 increase (∼357 ppm) is similar to that of Late Cretaceous OAE2 but of smaller magnitude than that of other major carbon cycle perturbations of the Mesozoic assessed via stomatal methods (e.g., the Toarcian OAE [TOAE], Triassic-Jurassic boundary event, Cretaceous-Paleogene Boundary event). Furthermore, our results indicate a possible shared causal or developmental mechanism with OAE1a and the TOAE.

  8. CO_2-assisted compression-adsorption hybrid for cooling and desalination

    International Nuclear Information System (INIS)

    Ali, Syed Muztuza; Chakraborty, Anutosh; Leong, Kai Choong

    2017-01-01

    Highlights: • Amalgamation of vapour compression and adsorption. • Thermodynamic frameworks of compression-adsorption hybrid. • 60% improvement in COP as compared with conventional CO_2 cooling system. • Energy recovery from CO_2 is used for cooling and desalination. • Energy from gas cooler accelerates the desalination process. - Abstract: This paper presents a novel compression-adsorption hybrid that symbiotically combines adsorption and CO_2 compression cooling devices. The seemingly low efficiency of each cycle individually is overcome by an amalgamation with the other. Hence, both heat and water vapour refrigerant mass are recovered for continuous cooling and desalination. Two different configurations are presented. The first configuration deals with a two-stage heat recovery system. At the first stage, heat is recovered from the compressed carbon dioxide to drive the adsorption device. The second stage heat recovery system internally exchanges heat between the low pressure and high pressure refrigerants of the CO_2 cycle. The second configuration is proposed with an additional third-stage heat recovery from the gas cooler to the high pressure evaporator of the adsorption cycle. The water vapour mass is recovered from bed-to-bed adsorption at relatively higher pressure. A detailed thermodynamic framework is presented to simulate the performances in terms of COP (coefficient of performance), SCP (specific cooling power), SDWP (specific daily water production), PR (performance ratio) and OCR (overall conversion ratio). It is found that the overall COP is improved by more than 60% as compared to the conventional CO_2 cycle, and in addition, the system generates 12.7 m"3 of desalinated water per tonne of silica gel per day as extra benefits. Furthermore, both the heat and mass recoveries improve the overall conversion ratio, which is almost double as compared to the conventional CO_2 cycle.

  9. China's CO2 emissions from power generating stations: A first exploration

    OpenAIRE

    Du, Limin; Hanley, Aoife; Rehdanz, Katrin

    2014-01-01

    Our analysis is the first of its kind to explore patterns of subsidization and CO2 emissions in China's electricity producing sector. Applying data for all power plants across China and controlling for the age, capacity and location of generating stations, we find that plants attracting a higher government subsidy are also worryingly the plants generating a disproportionate share of CO2 emissions. This distortion is incongruent with China's aspiration for a greener economy but may be eliminat...

  10. Multivariable Optimization of the Piperazine CO2 Post-Combustion Process

    DEFF Research Database (Denmark)

    Gaspar, Jozsef; von Solms, Nicolas; Thomsen, Kaj

    2016-01-01

    of the lean solvent. However, optimal solvent composition must be determined taking into account the solvent circulation rate and the heat demand of the solvent regeneration.In this paper, we determine and generalize trends of performance for a broad range of operating conditions: 1.8 to 9mol PZ/ kg water, 0.......2 to 0.6 lean loading, and for two flue gas sources: natural gas combined cycle power plant (NGCC, 3.9 mol% CO2) and a coal based power plant (ASC, 13.25 mol% CO2). Special attention is given to the boundaries where precipitation may occur. The results are created by the hybrid CAPCO2 rate-based model...... which accounts for precipitation when estimating the heat and mass transfer rates. The results show that the 7 molal piperazine gives the lowest specific reboiler duty at 0.40 CO2 lean loading: 3.32 GJ/t CO2 and 4.05 GJ/t CO2 for the ASC case and NGCC cases. The analysis also reveals that the capture...

  11. Comparison of CFD results for a supercritical CO{sub 2} compressor with compressible and incompressible working fluids

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Gu; Baik, Seungjoon; Cho, Seong Kuk; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of); Kwon, Jinsu [Hanyang University, Seoul (Korea, Republic of)

    2015-10-15

    The authors compared flow parameters of S-CO{sub 2} compressor with various fluids to investigate fluid characteristic of S-CO{sub 2}, and performance of pump-derived type (shrouded impeller) compressor. The CFD results showed that the isentropic efficiency of CO{sub 2} case has a comparable performance in comparison to the water since S-CO{sub 2} has a meta-incompressible characteristic near the critical point. Because of the low rotating speed and non-optimized geometry of impeller, the pressure ratio of the compressor is low. However, the authors confirmed that this shrouded type impeller for S-CO{sub 2} compressor showed good performance as much as water case. This results will be reflected in the future S-CO{sub 2} compressor design. As the generation IV reactors are being researched, the supercritical carbon dioxide (S-CO{sub 2}) Brayton cycle is identified as one of the promising power conversion cycles. The S-CO{sub 2} cycle has several advantages: high efficiency it has compact cycle components and simple layout. It can be also used for a power conversion system of sodium-cooled fast reactor (SFR) since it can eliminate potential safety issue of the sodium-water reactions. Moreover, the S-CO{sub 2} cycle can be used for small modular reactors (SMR) application since it occupies small footprint and it can designed as an economical dry-cooling system for SMRs. Design of a compressor is the major technical issue in development of S-CO{sub 2} cycle. Main purposes of this experiment are to accumulate operating experience of the S-CO{sub 2} loop, and to obtain fundamental data for the compressor design optimization near the critical point. However, inside the compressor, it is hard to know flow parameters by measurements. Therefore, the authors performed a CFD analysis to obtain useful flow parameters inside the compressor. The main goal of this paper is studying the flow parameters of pump-derived type compressor with S-CO{sub 2}, water, and air fluids to

  12. Metallic CoS₂ nanowire electrodes for high cycling performance supercapacitors.

    Science.gov (United States)

    Ren, Ren; Faber, Matthew S; Dziedzic, Rafal; Wen, Zhenhai; Jin, Song; Mao, Shun; Chen, Junhong

    2015-12-11

    We report metallic cobalt pyrite (CoS2) nanowires (NWs) prepared directly on current collecting electrodes, e.g., carbon cloth or graphite disc, for high-performance supercapacitors. These CoS2 NWs have a variety of advantages for supercapacitor applications. Because the metallic CoS2 NWs are synthesized directly on the current collector, the good electrical connection enables efficient charge transfer between the active CoS2 materials and the current collector. In addition, the open spaces between the sea urchin structure NWs lead to a large accessible surface area and afford rapid mass transport. Moreover, the robust CoS2 NW structure results in high stability of the active materials during long-term operation. Electrochemical characterization reveals that the CoS2 NWs enable large specific capacitance (828.2 F g(-1) at a scan rate of 0.01 V s(-1)) and excellent long term cycling stability (0-2.5% capacity loss after 4250 cycles at 5 A g(-1)) for pseudocapacitors. This example of metallic CoS2 NWs for supercapacitor applications expands the opportunities for transition metal sulfide-based nanostructures in emerging energy storage applications.

  13. The response of vegetation to rising CO2 concentrations plays an important role in future changes in the hydrological cycle

    Science.gov (United States)

    Hong, Tao; Dong, Wenjie; Ji, Dong; Dai, Tanlong; Yang, Shili; Wei, Ting

    2018-04-01

    The effects of increasing CO2 concentrations on plant and carbon cycle have been extensively investigated; however, the effects of changes in plants on the hydrological cycle are still not fully understood. Increases in CO2 modify the stomatal conductance and water use of plants, which may have a considerable effect on the hydrological cycle. Using the carbon-climate feedback experiments from CMIP5, we estimated the responses of plants and hydrological cycle to rising CO2 concentrations to double of pre-industrial levels without climate change forcing. The mode results show that rising CO2 concentrations had a significant influence on the hydrological cycle by changing the evaporation and transpiration of plants and soils. The increases in the area covered by plant leaves result in the increases in vegetation evaporation. Besides, the physiological effects of stomatal closure were stronger than the opposite effects of changes in plant structure caused by the increases in LAI (leaf area index), which results in the decrease of transpiration. These two processes lead to overall decreases in evaporation, and then contribute to increases in soil moisture and total runoff. In the dry areas, the stronger increase in LAI caused the stronger increases in vegetation evaporation and then lead to the overall decreases in P - E (precipitation minus evaporation) and soil moisture. However, the soil moisture in sub-arid and wet areas would increase, and this may lead to the soil moisture deficit worse in the future in the dry areas. This study highlights the need to consider the different responses of plants and the hydrological cycle to rising CO2 in dry and wet areas in future water resources management, especially in water-limited areas.

  14. Effect of Suction Nozzle Pressure Drop on the Performance of an Ejector-Expansion Transcritical CO2 Refrigeration Cycle

    Directory of Open Access Journals (Sweden)

    Zhenying Zhang

    2014-08-01

    Full Text Available The basic transcritical CO2 systems exhibit low energy efficiency due to their large throttling loss. Replacing the throttle valve with an ejector is an effective measure for recovering some of the energy lost in the expansion process. In this paper, a thermodynamic model of the ejector-expansion transcritical CO2 refrigeration cycle is developed. The effect of the suction nozzle pressure drop (SNPD on the cycle performance is discussed. The results indicate that the SNPD has little impact on entrainment ratio. There exists an optimum SNPD which gives a maximum recovered pressure and COP under a specified condition. The value of the optimum SNPD mainly depends on the efficiencies of the motive nozzle and the suction nozzle, but it is essentially independent of evaporating temperature and gas cooler outlet temperature. Through optimizing the value of SNPD, the maximum COP of the ejector-expansion cycle can be up to 45.1% higher than that of the basic cycle. The exergy loss of the ejector-expansion cycle is reduced about 43.0% compared with the basic cycle.

  15. Net Energy Payback and CO2 Emissions from Three Midwestern Wind Farms: An Update

    International Nuclear Information System (INIS)

    White, Scott W.

    2006-01-01

    This paper updates a life-cycle net energy analysis and carbon dioxide emissions analysis of three Midwestern utility-scale wind systems. Both the Energy Payback Ratio (EPR) and CO 2 analysis results provide useful data for policy discussions regarding an efficient and low-carbon energy mix. The EPR is the amount of electrical energy produced for the lifetime of the power plant divided by the total amount of energy required to procure and transport the materials, build, operate, and decommission the power plants. The CO 2 analysis for each power plant was calculated from the life-cycle energy input data.A previous study also analyzed coal and nuclear fission power plants. At the time of that study, two of the three wind systems had less than a full year of generation data to project the life-cycle energy production. This study updates the analysis of three wind systems with an additional four to eight years of operating data.The EPR for the utility-scale wind systems ranges from a low of 11 for a two-turbine system in Wisconsin to 28 for a 143-turbine system in southwestern Minnesota. The EPR is 11 for coal, 25 for fission with gas centrifuge enriched uranium and 7 for gaseous diffusion enriched uranium. The normalized CO 2 emissions, in tonnes of CO 2 per GW e h, ranges from 14 to 33 for the wind systems, 974 for coal, and 10 and 34 for nuclear fission using gas centrifuge and gaseous diffusion enriched uranium, respectively

  16. Net energy payback and CO2 emissions from three midwestern wind farms: An update

    Science.gov (United States)

    White, S.W.

    2006-01-01

    This paper updates a life-cycle net energy analysis and carbon dioxide emissions analysis of three Midwestern utility-scale wind systems. Both the Energy Payback Ratio (EPR) and CO2 analysis results provide useful data for policy discussions regarding an efficient and low-carbon energy mix. The EPR is the amount of electrical energy produced for the lifetime of the power plant divided by the total amount of energy required to procure and transport the materials, build, operate, and decommission the power plants. The CO2 analysis for each power plant was calculated from the life-cycle energy input data. A previous study also analyzed coal and nuclear fission power plants. At the time of that study, two of the three wind systems had less than a full year of generation data to project the life-cycle energy production. This study updates the analysis of three wind systems with an additional four to eight years of operating data. The EPR for the utility-scale wind systems ranges from a low of 11 for a two-turbine system in Wisconsin to 28 for a 143-turbine system in southwestern Minnesota. The EPR is 11 for coal, 25 for fission with gas centrifuge enriched uranium and 7 for gaseous diffusion enriched uranium. The normalized CO2 emissions, in tonnes of CO2 per GW eh, ranges from 14 to 33 for the wind systems, 974 for coal, and 10 and 34 for nuclear fission using gas centrifuge and gaseous diffusion enriched uranium, respectively. ?? Springer Science+Business Media, LLC 2007.

  17. Concurrent separation of CO2 and H2O from air by a temperature-vacuum swing adsorption/desorption cycle.

    Science.gov (United States)

    Wurzbacher, Jan Andre; Gebald, Christoph; Piatkowski, Nicolas; Steinfeld, Aldo

    2012-08-21

    A temperature-vacuum swing (TVS) cyclic process is applied to an amine-functionalized nanofibrilated cellulose sorbent to concurrently extract CO(2) and water vapor from ambient air. The promoting effect of the relative humidity on the CO(2) capture capacity and on the amount of coadsorbed water is quantified. The measured specific CO(2) capacities range from 0.32 to 0.65 mmol/g, and the corresponding specific H(2)O capacities range from 0.87 to 4.76 mmol/g for adsorption temperatures varying between 10 and 30 °C and relative humidities varying between 20 and 80%. Desorption of CO(2) is achieved at 95 °C and 50 mbar(abs) without dilution by a purge gas, yielding a purity exceeding 94.4%. Sorbent stability and a closed mass balance for both H(2)O and CO(2) are demonstrated for ten consecutive adsorption-desorption cycles. The specific energy requirements of the TVS process based on the measured H(2)O and CO(2) capacities are estimated to be 12.5 kJ/mol(CO2) of mechanical (pumping) work and between 493 and 640 kJ/mol(CO2) of heat at below 100 °C, depending on the air relative humidity. For a targeted CO(2) capacity of 2 mmol/g, the heat requirement would be reduced to between 272 and 530 kJ/mol(CO2), depending strongly on the amount of coadsorbed water.

  18. Energy Conversion Advanced Heat Transport Loop and Power Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Oh, C. H.

    2006-08-01

    The Department of Energy and the Idaho National Laboratory are developing a Next Generation Nuclear Plant (NGNP) to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is two fold 1) efficient low cost energy generation and 2) hydrogen production. Although a next generation plant could be developed as a single-purpose facility, early designs are expected to be dual-purpose. While hydrogen production and advanced energy cycles are still in its early stages of development, research towards coupling a high temperature reactor, electrical generation and hydrogen production is under way. Many aspects of the NGNP must be researched and developed in order to make recommendations on the final design of the plant. Parameters such as working conditions, cycle components, working fluids, and power conversion unit configurations must be understood. Three configurations of the power conversion unit were demonstrated in this study. A three-shaft design with 3 turbines and 4 compressors, a combined cycle with a Brayton top cycle and a Rankine bottoming cycle, and a reheated cycle with 3 stages of reheat were investigated. An intermediate heat transport loop for transporting process heat to a High Temperature Steam Electrolysis (HTSE) hydrogen production plant was used. Helium, CO2, and an 80% nitrogen, 20% helium mixture (by weight) were studied to determine the best working fluid in terms cycle efficiency and development cost. In each of these configurations the relative component size were estimated for the different working fluids. The relative size of the turbomachinery was measured by comparing the power input/output of the component. For heat exchangers the volume was computed and compared. Parametric studies away from the baseline values of the three-shaft and combined cycles were performed to determine the effect of varying conditions in the cycle. This gives some insight into the sensitivity of these cycles to various

  19. An optimal multivariable controller for transcritical CO2 refrigeration cycle with an adjustable ejector

    International Nuclear Information System (INIS)

    He, Yang; Deng, Jianqiang; Yang, Fusheng; Zhang, Zaoxiao

    2017-01-01

    Highlights: • Dynamic model for transcritical CO 2 ejector refrigeration system is developed. • A model-driven optimal multivariable controller is proposed. • Gas cooler pressure and cooling capacity are tracked independently. • Maximal performance for a given load is achieved by the optimal controller. - Abstract: The fixed ejector has to work under a restricted operating condition to keep its positive effectiveness on the transcritical CO 2 refrigeration cycle, and a controllable ejector will be helpful. In this paper, an optimal multivariable controller based on the dynamic model is proposed to improve transcritical CO 2 refrigeration cycle with an adjustable ejector (TCRAE). A nonlinear dynamic model is first developed to model the dynamic characteristic of TCRAE. The corresponding model linearization is carried out and the simulation results reproduce transient behavior of the nonlinear model very well. Based on the developed model, an optimal multivariable controller with a tracker based linear quadratic state feedback algorithm and a predictor using steepest descent method is designed. The controller is finally applied on the experimental apparatus and the performance is verified. Using the tracker only, the gas cooler pressure and chilled water outlet temperature (cooling capacity) are well tracked rejecting the disturbances from each other. Furthermore, by the predictor, the optimal gas cooler pressure for a constant cooling capacity is actually approached on the experimental apparatus with a settling time about 700 s.

  20. Ultra-Low Carbon Emissions from Coal-Fired Power Plants through Bio-Oil Co-Firing and Biochar Sequestration.

    Science.gov (United States)

    Dang, Qi; Mba Wright, Mark; Brown, Robert C

    2015-12-15

    This study investigates a novel strategy of reducing carbon emissions from coal-fired power plants through co-firing bio-oil and sequestering biochar in agricultural lands. The heavy end fraction of bio-oil recovered from corn stover fast pyrolysis is blended and co-fired with bituminous coal to form a bio-oil co-firing fuel (BCF). Life-cycle greenhouse gas (GHG) emissions per kWh electricity produced vary from 1.02 to 0.26 kg CO2-eq among different cases, with BCF heavy end fractions ranging from 10% to 60%, which corresponds to a GHG emissions reduction of 2.9% to 74.9% compared with that from traditional bituminous coal power plants. We found a heavy end fraction between 34.8% and 37.3% is required to meet the Clean Power Plan's emission regulation for new coal-fired power plants. The minimum electricity selling prices are predicted to increase from 8.8 to 14.9 cents/kWh, with heavy end fractions ranging from 30% to 60%. A minimum carbon price of $67.4 ± 13 per metric ton of CO2-eq was estimated to make BCF power commercially viable for the base case. These results suggest that BCF co-firing is an attractive pathway for clean power generation in existing power plants with a potential for significant reductions in carbon emissions.

  1. Performance Analysis of Cold Energy Recovery from CO2 Injection in Ship-Based Carbon Capture and Storage (CCS

    Directory of Open Access Journals (Sweden)

    Hwalong You

    2014-11-01

    Full Text Available Carbon capture and storage (CCS technology is one of the practical solutions for mitigating the effects of global warming. When captured CO2 is injected into storage sites, the CO2 is subjected to a heating process. In a conventional CO2 injection system, CO2 cold energy is wasted during this heating process. This study proposes a new CO2 injection system that takes advantage of the cold energy using the Rankine cycle. The study compared the conventional system with the new CO2 injection system in terms of specific net power consumption, exergy efficiency, and life-cycle cost (LCC to estimate the economic effects. The results showed that the new system reduced specific net power consumption and yielded higher exergy efficiency. The LCC of the new system was more economical. Several cases were examined corresponding to different conditions, specifically, discharge pressure and seawater temperature. This information may affect decision-making when CCS projects are implemented.

  2. Gasoline-powered series hybrid cars cause lower life cycle carbon emissions than battery cars

    Science.gov (United States)

    Meinrenken, Christoph; Lackner, Klaus S.

    2012-02-01

    Battery cars powered by grid electricity promise reduced life cycle green house gas (GHG) emissions from the automotive sector. Such scenarios usually point to the much higher emissions from conventional, internal combustion engine cars. However, today's commercially available series hybrid technology achieves the well known efficiency gains in electric drivetrains (regenerative breaking, lack of gearbox) even if the electricity is generated onboard, from conventional fuels. Here, we analyze life cycle GHG emissions for commercially available, state-of the-art plug-in battery cars (e.g. Nissan Leaf) and those of commercially available series hybrid cars (e.g., GM Volt, at same size and performance). Crucially, we find that series hybrid cars driven on (fossil) gasoline cause fewer emissions (126g CO2eq per km) than battery cars driven on current US grid electricity (142g CO2eq per km). We attribute this novel finding to the significant incremental emissions from plug-in battery cars due to losses during grid transmission and battery dis-/charging, and manufacturing larger batteries. We discuss crucial implications for strategic policy decisions towards a low carbon automotive sector as well as relative land intensity when powering cars by biofuel vs. bioelectricity.

  3. Trend of CO{sub 2} emissions of the 30 largest power plants in Germany; Trendentwicklung der CO{sub 2}-Emissionen der 30 groessten Kraftwerke in Deutschland. Kurzanalyse basierend auf aktuellen Emissionshandelsdaten

    Energy Technology Data Exchange (ETDEWEB)

    Hermann, Hauke

    2014-04-02

    The brochure on the trend of CO{sub 2} emissions of the 30 largest power plants in Germany includes tables of the emissions of these power plants. The CO{sub 2} emissions of these power plants in 2013 (25% of the total German greenhouse gas emissions) have increased by 5% compared to 2012. The total CO{sub 2} emission sin Germany increased by 1.5%. The differences between brown coal and black coal fired power plants are discussed.

  4. Enhanced cycling stability of microsized LiCoO2 cathode by Li4Ti5O12 coating for lithium ion battery

    International Nuclear Information System (INIS)

    Yi, Ting-Feng; Shu, J.; Yue, Cai-Bo; Zhu, Xiao-Dong; Zhou, An-Na; Zhu, Yan-Rong; Zhu, Rong-Sun

    2010-01-01

    The effect of Li 4 Ti 5 O 12 (LTO) coating amount on the electrochemical cycling behavior of the LiCoO 2 cathode was investigated at the high upper voltage limit of 4.5 V. Li 4 Ti 5 O 12 (≤5 wt.%) is not incorporated into the host structure and leads to formation of uniform coating. The cycling performance of LiCoO 2 cathode is related with the amount of Li 4 Ti 5 O 12 coating. The initial capacity of the LTO-coated LiCoO 2 decreased with increasing Li 4 Ti 5 O 12 coating amount but showed enhanced cycling properties, compared to those of pristine material. The 3 wt.% LTO-coated LiCoO 2 has the best electrochemical performance, showing capacity retention of 97.3% between 2.5 V and 4.3 V and 85.1% between 2.5 V and 4.5 V after 40 cycles. The coulomb efficiency shows that the surface coating of Li 4 Ti 5 O 12 is beneficial to the reversible intercalation/de-intercalation of Li + . LTO-coated LiCoO 2 provides good prospects for practical application of lithium secondary batteries free from safety issues.

  5. Theoretical studies of a hybrid ejector CO2 compression cooling system for vehicles and preliminary experimental investigations of an ejector cycle

    International Nuclear Information System (INIS)

    Chen, Xiangjie; Worall, Mark; Omer, Siddig; Su, Yuehong; Riffat, Saffa

    2013-01-01

    Highlights: ► Waste heat from vehicle exhausted gas was used as heat source for ejector. ► Ejector acts as the main interface between ejector and CO 2 VC sub-system. ► The effect of sub-cooling was analyzed. ► COP of ejector cooling system was measured between 0.2 and 0.5 during experiments. ► Enhanced ejector and vapour compression system. -- Abstract: This paper presents theoretical investigations into a hybrid ejector and CO 2 vapour compression (VC) system for road transport cooling. The purpose is to utilise the waste heat from exhaust gas and the VC sub-system to drive the ejector system, whose cooling effect will be employed to subcool the VC sub-system. Exploitation of the energy consumption ratio between ejector sub-system and CO 2 VC sub-system indicated that the more energy obtained from exhausted gas, the better system performance could be achieved for CO 2 VC sub-system, and hence higher cooling capacity of the VC sub-system at the same compression power. Thermodynamic simulations of two sub-systems and the hybrid system were presented. The results indicated that, at boiler temperature of 120 °C, evaporator temperature of 10 °C, a COP of 0.584 was achieved for hybrid system, with 22% improvement over a single ejector cycle. Preliminary experimental studies were carried out on a single ejector cycle, with boiler temperatures between 115 °C and 130 °C, and evaporator temperatures between 5 °C and 10 °C. The effects of various operation conditions on the overall ejector operation were coherently analysed. The COP of the ejector sub-system from experimental results was approximately 85% compared with simulation results, which showed a good agreement between theoretical analysis and experimental results.

  6. Response of Nodularia spumigena to pCO2 – Part 1: Growth, production and nitrogen cycling

    Directory of Open Access Journals (Sweden)

    M. Nausch

    2012-08-01

    Full Text Available Heterocystous cyanobacteria of the genus Nodularia form extensive blooms in the Baltic Sea and contribute substantially to the total annual primary production. Moreover, they dispense a large fraction of new nitrogen to the ecosystem when inorganic nitrogen concentration in summer is low. Thus, it is of ecological importance to know how Nodularia will react to future environmental changes, in particular to increasing carbon dioxide (CO2 concentrations and what consequences there might arise for cycling of organic matter in the Baltic Sea. Here, we determined carbon (C and dinitrogen (N2 fixation rates, growth, elemental stoichiometry of particulate organic matter and nitrogen turnover in batch cultures of the heterocystous cyanobacterium Nodularia spumigena under low (median 315 μatm, mid (median 353 μatm, and high (median 548 μatm CO2 concentrations. Our results demonstrate an overall stimulating effect of rising pCO2 on C and N2 fixation, as well as on cell growth. An increase in pCO2 during incubation days 0 to 9 resulted in an elevation in growth rate by 84 ± 38% (low vs. high pCO2 and 40 ± 25% (mid vs. high pCO2, as well as in N2 fixation by 93 ± 35% and 38 ± 1%, respectively. C uptake rates showed high standard deviations within treatments and in between sampling days. Nevertheless, C fixation in the high pCO2 treatment was elevated compared to the other two treatments by 97% (high vs. low and 44% (high vs. mid at day 0 and day 3, but this effect diminished afterwards. Additionally, elevation in carbon to nitrogen and nitrogen to phosphorus ratios of the particulate biomass formed (POC : POP and PON : POP was observed at high pCO2. Our findings suggest that rising pCO2 stimulates the growth of heterocystous diazotrophic cyanobacteria, in a similar way as reported for the non-heterocystous diazotroph Trichodesmium. Implications for biogeochemical cycling and food web dynamics, as well as ecological and socio-economical aspects in the

  7. Optimum heat power cycles for specified boundary conditions

    International Nuclear Information System (INIS)

    Ibrahim, O.M.; Klein, S.A.; Mitchell, J.W.

    1991-01-01

    In this paper optimization of the power output of Carnot and closed Brayton cycles is considered for both finite and infinite thermal capacitance rates of the external fluid streams. The method of Lagrange multipliers is used to solve for working fluid temperatures that yield maximum power. Analytical expressions for the maximum power and the cycle efficiency at maximum power are obtained. A comparison of the maximum power from the two cycles for the same boundary conditions, i.e., the same heat source/sink inlet temperatures, thermal capacitance rates, and heat exchanger conductances, shows that the Brayton cycle can produce more power than the Carnot cycle. This comparison illustrates that cycles exist that can produce more power than the Carnot cycle. The optimum heat power cycle, which will provide the upper limit of power obtained from any thermodynamic cycle for specified boundary conditions and heat exchanger conductances is considered. The optimum heat power cycle is identified by optimizing the sum of the power output from a sequence of Carnot cycles. The shape of the optimum heat power cycle, the power output, and corresponding efficiency are presented. The efficiency at maximum power of all cycles investigated in this study is found to be equal to (or well approximated by) η = 1 - sq. root T L.in /φT H.in where φ is a factor relating the entropy changes during heat rejection and heat addition

  8. Life cycle energy metrics and CO 2 credit analysis of a hybrid photovoltaic/thermal greenhouse dryer

    OpenAIRE

    P. Barnwal; G. N. Tiwari

    2008-01-01

    In this paper, life cycle energy metrics, such as energy payback time (EPBT), energy production factor (EPF) and life cycle conversion efficiency (LCCE), and mitigation of CO 2 emissions for a hybrid photovoltaic/thermal (PV/T) greenhouse dryer have been analyzed. The hybrid PV/T greenhouse (roof type even span) dryer, designed and constructed at Solar Energy Park, Indian Institute of Technology, New Delhi (28°35′N, 77°12′E, 216 m above MSL), India, has a 2.50 m × 2.60 m floor area, 1.80 m ce...

  9. Life cycle assessment of energy and CO2 emissions for residential buildings in Jakarta, Indonesia

    Science.gov (United States)

    Surahman, U.; Kubota, T.; Wijaya, A.

    2016-04-01

    In order to develop low energy and low carbon residential buildings, it is important to understand their detailed energy profiles. This study provides the results of life cycle assessment of energy and CO2 emissions for residential buildings in Jakarta, Indonesia. A survey was conducted in the city in 2012 to obtain both material inventory and household energy consumption data within the selected residential buildings (n=300), which are classified into three categories, namely simple, medium and luxurious houses. The results showed that the average embodied energy of simple, medium and luxurious houses was 58.5, 201.0, and 559.5 GJ, respectively. It was found that total embodied energy of each house can be explained by its total floor area alone with high accuracy in respective house categories. Meanwhile, it was seen that operational energy usage patterns varied largely among house categories as well as households especially in the simple and medium houses. The energy consumption for cooling was found to be the most significant factor of the increase in operational energy from simple to luxurious houses. Further, in the life cycle energy, the operational energy accounted for much larger proportions of about 86-92% than embodied energy regardless of the house categories. The life cycle CO2 emissions for medium and luxurious houses were larger than that of simple houses by 2 and 6 times on average. In the simple houses, cooking was the largest contributor to the CO2 emissions (25%), while the emissions caused by cooling increased largely with the house category and became the largest contributors in the medium (26%) and luxurious houses (41%).

  10. Interactions between plant growth and soil nutrient cycling under elevated CO2: a meta-analysis

    NARCIS (Netherlands)

    Graaff, de M.A.; Groenigen, van K.J.; Six, J.; Hungate, B.; Kessel, van C.

    2006-01-01

    free air carbon dioxide enrichment (FACE) and open top chamber (OTC) studies are valuable tools for evaluating the impact of elevated atmospheric CO2 on nutrient cycling in terrestrial ecosystems. Using meta-analytic techniques, we summarized the results of 117 studies on plant biomass production,

  11. Fuel cell hybrid taxi life cycle analysis

    Energy Technology Data Exchange (ETDEWEB)

    Baptista, Patricia, E-mail: patricia.baptista@ist.utl.pt [IDMEC-Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa (Portugal); Ribau, Joao; Bravo, Joao; Silva, Carla [IDMEC-Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa (Portugal); Adcock, Paul; Kells, Ashley [Intelligent Energy, Charnwood Building, HolywellPark, Ashby Road, Loughborough, LE11 3GR (United Kingdom)

    2011-09-15

    A small fleet of classic London Taxis (Black cabs) equipped with hydrogen fuel cell power systems is being prepared for demonstration during the 2012 London Olympics. This paper presents a Life Cycle Analysis for these vehicles in terms of energy consumption and CO{sub 2} emissions, focusing on the impacts of alternative vehicle technologies for the Taxi, combining the fuel life cycle (Tank-to-Wheel and Well-to-Tank) and vehicle materials Cradle-to-Grave. An internal combustion engine diesel taxi was used as the reference vehicle for the currently available technology. This is compared to battery and fuel cell vehicle configurations. Accordingly, the following energy pathways are compared: diesel, electricity and hydrogen (derived from natural gas steam reforming). Full Life Cycle Analysis, using the PCO-CENEX drive cycle, (derived from actual London Taxi drive cycles) shows that the fuel cell powered vehicle configurations have lower energy consumption (4.34 MJ/km) and CO{sub 2} emissions (235 g/km) than both the ICE Diesel (9.54 MJ/km and 738 g/km) and the battery electric vehicle (5.81 MJ/km and 269 g/km). - Highlights: > A Life Cycle Analysis of alternative vehicle technologies for the London Taxi was performed. > The hydrogen powered vehicles have the lowest energy consumption and CO{sub 2} emissions results. > A hydrogen powered solution can be a sustainable alternative in a full life cycle framework.

  12. Fuel cell hybrid taxi life cycle analysis

    International Nuclear Information System (INIS)

    Baptista, Patricia; Ribau, Joao; Bravo, Joao; Silva, Carla; Adcock, Paul; Kells, Ashley

    2011-01-01

    A small fleet of classic London Taxis (Black cabs) equipped with hydrogen fuel cell power systems is being prepared for demonstration during the 2012 London Olympics. This paper presents a Life Cycle Analysis for these vehicles in terms of energy consumption and CO 2 emissions, focusing on the impacts of alternative vehicle technologies for the Taxi, combining the fuel life cycle (Tank-to-Wheel and Well-to-Tank) and vehicle materials Cradle-to-Grave. An internal combustion engine diesel taxi was used as the reference vehicle for the currently available technology. This is compared to battery and fuel cell vehicle configurations. Accordingly, the following energy pathways are compared: diesel, electricity and hydrogen (derived from natural gas steam reforming). Full Life Cycle Analysis, using the PCO-CENEX drive cycle, (derived from actual London Taxi drive cycles) shows that the fuel cell powered vehicle configurations have lower energy consumption (4.34 MJ/km) and CO 2 emissions (235 g/km) than both the ICE Diesel (9.54 MJ/km and 738 g/km) and the battery electric vehicle (5.81 MJ/km and 269 g/km). - Highlights: → A Life Cycle Analysis of alternative vehicle technologies for the London Taxi was performed. → The hydrogen powered vehicles have the lowest energy consumption and CO 2 emissions results. → A hydrogen powered solution can be a sustainable alternative in a full life cycle framework.

  13. The Life Cycle CO2 (LCCO2 Evaluation of Retrofits for Water-Saving Fittings

    Directory of Open Access Journals (Sweden)

    Yasutoshi Shimizu

    2013-05-01

    Full Text Available As part of measures being taken against global warming, the reduction of CO2 emissions by retrofitting for water-saving fittings in homes is spreading throughout the world. However, although this retrofitting reduces the environmental impact at the use stage, it generates new impacts at the production and disposal stages. In addition, there has been little research that discusses the reduction in environmental impact obtained by retrofitting from the viewpoint of the overall life cycle of such fittings. In this paper, an evaluation of the environmental impact of retrofitting in terms of the entire life cycle was carried out for toilet bowls and showerheads. The findings show that even for a toilet bowl that generates a large environmental load at the production stage, there is no overall increase in the environmental impact by retrofitting for the average usable life of 20 years.

  14. Elevated CO2, not defoliation, enhances N cycling and increases short-term soil N immobilization regardless of N addition in a semiarid grassland

    Science.gov (United States)

    Elevated CO2 and defoliation effects on nitrogen (N) cycling in rangeland soils remain poorly understood. Here we tested whether effects of elevated CO2 and defoliation (clipping to 2.5 cm height) on N cycling depended on soil N availability (addition of 1 vs. 11 g N/m2) in intact mesocosms extracte...

  15. Manufacturing of cast fittings for power machine building using improved CO2-process

    International Nuclear Information System (INIS)

    Shuvalov, V.G.; Borodin, M.A.

    1984-01-01

    Technique for manufacturing of rods for casting fittings for power machines of heat and nuclear power plants using liquid-glass mixtures solidified by CO 2 is described. Optimal composition of mixtures and their basic technological properties were determined

  16. Life-Cycle Evaluation of Domestic Energy Systems

    Science.gov (United States)

    Bando, Shigeru; Hihara, Eiji

    Among the growing number of environmental issues, the global warming due to the increasing emission of greenhouse gases, such as carbon dioxide CO2, is the most serious one. In order to reduce CO2 emissions in energy use, it is necessary to reduce primary energy consumption, and to replace energy sources with alternatives that emit less CO2.One option of such ideas is to replace fossil gas for water heating with electricity generated by nuclear power, hydraulic power, and other methods with low CO2 emission. It is also important to use energy efficiently and to reduce waste heat. Co-generation system is one of the applications to be able to use waste heat from a generator as much as possible. The CO2 heat pump water heaters, the polymer electrolyte fuel cells, and the micro gas turbines have high potential for domestic energy systems. In the present study, the life-cycle cost, the life-cycle consumption of primary energy and the life-cycle emission of CO2 of these domestic energy systems are compare. The result shows that the CO2 heat pump water heaters have an ability to reduce CO2 emission by 10%, and the co-generation systems also have another ability to reduce primary energy consumption by 20%.

  17. High-energy asymmetric supercapacitors based on free-standing hierarchical Co-Mo-S nanosheets with enhanced cycling stability.

    Science.gov (United States)

    Balamurugan, Jayaraman; Li, Chao; Peera, Shaik Gouse; Kim, Nam Hoon; Lee, Joong Hee

    2017-09-21

    Layered transition metal sulfides (TMS) are emerging as advanced materials for energy storage and conversion applications. In this work, we report a facile and cost-effective anion exchange technique to fabricate a layered, multifaceted, free standing, ultra-thin ternary cobalt molybdenum sulfide nanosheet (Co-Mo-S NS) architecture grown on a 3D porous Ni foam substrate. The unique Co-Mo layered double hydroxides are first synthesized as precursors and consequently transformed into ultra-thin Co-Mo-S NS. When employed as an electrode for supercapacitors, the Co-Mo-S NS delivered an ultra-high specific capacitance of 2343 F g -1 at a current density of 1 mA cm -2 with tremendous rate capability and extraordinary cycling performance (96.6% capacitance retention after 20 000 cycles). Furthermore, assembled Co-Mo-S/nitrogen doped graphene nanosheets (NGNS) in an asymmetric supercapacitor (ASC) device delivered an excellent energy density of 89.6 Wh kg -1 , an amazing power density of 20.07 kW kg -1 , and superior cycling performance (86.8% capacitance retention after 50 000 cycles). Such exceptional electrochemical performance of Co-Mo-S NS is ascribed to the good electrical contact with the 3D Ni foam, ultra-high contact area with the electrolyte, and enhanced architectural softening during the charging/discharging process. It is expected that the fabricated, unique, ultra-thin Co-Mo-S NS have great potential for future energy storage devices.

  18. Performance Estimation of Supercritical Co2 Micro Modular Reactor (MMR) for Varying Cooling Air Temperature

    International Nuclear Information System (INIS)

    Ahn, Yoonhan; Kim, Seong Gu; Cho, Seong Kuk; Lee, Jeong Ik

    2015-01-01

    A Small Modular Reactor (SMR) receives interests for the various application such as electricity co-generation, small-scale power generation, seawater desalination, district heating and propulsion. As a part of SMR development, supercritical CO2 Micro Modular Reactor (MMR) of 36.2MWth in power is under development by the KAIST research team. To enhance the mobility, the entire system including the power conversion system is designed for the full modularization. Based on the preliminary design, the thermal efficiency is 31.5% when CO2 is sufficiently cooled to the design temperature. A supercritical CO2 MMR is designed to supply electricity to the remote regions. The ambient temperature of the area can influence the compressor inlet temperature as the reactor is cooled with the atmospheric air. To estimate the S-CO2 cycle performance for various environmental conditions, A quasi-static analysis code is developed. For the off design performance of S-CO2 turbomachineries, the experimental result of Sandia National Lab (SNL) is utilized

  19. Emission of CO2 Gas and Radioactive Pollutant from Coal Fired Power Plant

    International Nuclear Information System (INIS)

    Ida, N.Finahari; Djati-HS; Heni-Susiati

    2006-01-01

    Energy utilization for power plant in Indonesia is still depending on burning fossil fuel such as coal, oil and gaseous fuel. The direct burning of coal produces CO 2 gas that can cause air pollution, and radioactive pollutant that can increase natural radioactive dosage. Natural radionuclide contained in coal is in the form of kalium, uranium, thorium and their decay products. The amount of CO 2 gas emission produced by coal fired power plant can be reduced by equipping the plant with waste-gas treatment facility. At this facility, CO 2 gas is reacted with calcium hydroxide producing calcium carbonate. Calcium carbonate then can be used as basic material in food, pharmaceutical and construction industries. The alternative method to reduce impact of air pollution is by replacing coal fuel with nuclear fuel or new and renewable fuel. (author)

  20. Materials, Turbomachinery and Heat Exchangers for Supercritical CO2 Systems

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark; Nellis, Greg; Corradini, Michael

    2012-10-19

    The objective of this project is to produce the necessary data to evaluate the performance of the supercritical carbon dioxide cycle. The activities include a study of materials compatibility of various alloys at high temperatures, the heat transfer and pressure drop in compact heat exchanger units, and turbomachinery issues, primarily leakage rates through dynamic seals. This experimental work will serve as a test bed for model development and design calculations, and will help define further tests necessary to develop high-efficiency power conversion cycles for use on a variety of reactor designs, including the sodium fast reactor (SFR) and very high-temperature gas reactor (VHTR). The research will be broken into three separate tasks. The first task deals with the analysis of materials related to the high-temperature S-CO{sub 2} Brayton cycle. The most taxing materials issues with regard to the cycle are associated with the high temperatures in the reactor side heat exchanger and in the high-temperature turbine. The system could experience pressures as high as 20MPa and temperatures as high as 650°C. The second task deals with optimization of the heat exchangers required by the S-CO{sub 2} cycle; the S-CO{sub 2} flow passages in these heat exchangers are required whether the cycle is coupled with a VHTR or an SFR. At least three heat exchangers will be required: the pre-cooler before compression, the recuperator, and the heat exchanger that interfaces with the reactor coolant. Each of these heat exchangers is unique and must be optimized separately. The most challenging heat exchanger is likely the pre-cooler, as there is only about a 40°C temperature change but it operates close to the CO{sub 2} critical point, therefore inducing substantial changes in properties. The proposed research will focus on this most challenging component. The third task examines seal leakage through various dynamic seal designs under the conditions expected in the S-CO{sub 2} cycle

  1. Gas--steam turbine combined cycle power plants

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J.E.

    1978-10-01

    The purpose of this technology evaluation is to provide performance and cost characteristics of the combined gas and steam turbine, cycle system applied to an Integrated Community Energy System (ICES). To date, most of the applications of combined cycles have been for electric power generation only. The basic gas--steam turbine combined cycle consists of: (1) a gas turbine-generator set, (2) a waste-heat recovery boiler in the gas turbine exhaust stream designed to produce steam, and (3) a steam turbine acting as a bottoming cycle. Because modification of the standard steam portion of the combined cycle would be necessary to recover waste heat at a useful temperature (> 212/sup 0/F), some sacrifice in the potential conversion efficiency is necessary at this temperature. The total energy efficiency ((electric power + recovered waste heat) divided by input fuel energy) varies from about 65 to 73% at full load to 34 to 49% at 20% rated electric power output. Two major factors that must be considered when installing a gas--steam turbine combines cycle are: the realiability of the gas turbine portion of the cycle, and the availability of liquid and gas fuels or the feasibility of hooking up with a coal gasification/liquefaction process.

  2. LMTD Design Methodology Assessment of Spiral Tube Heat Exchanger under the S-CO2 cycle operating condition

    International Nuclear Information System (INIS)

    Jung, Hwa Young; Lee, Jeong Ik; Ahn, Yoon Han

    2013-01-01

    The advantages of PCHE are compact high pressure difference endurance high temperature operation. However, PCHE is quite expensive and the resistance to the fast thermal cycling is questionable. In order to overcome this problem, the Korea Advanced Institute of Science and Technology (KAIST) research team is considering an alternative for the PCHE. Currently KAIST research team is using a Spiral Tube Heat Exchanger (STHE) of Sentry Equipment Corp. as a pre cooler in the SCO 2 PE facility. A STHE is relatively cheap but the operating pressure and temperature are acceptable for utilizing it as a pre cooler. A STHE is consisted of spiral shaped tubes (hot side i.e. S-CO 2 ) immersed in a shell (cold side i.e. water). This study is aimed at whether the logarithmic mean temperature difference (LMTD) heat exchanger design methodology is acceptable for designing the S-CO 2 cycle pre cooler. This is because the LMTD method usually assumes a constant specific heat, but the pre cooler in the S-CO 2 cycle operates at the nearest point to the critical point where a dramatic change in properties is expected. Experimentally obtained data are compared to the vendor provided technical specification based on the LMTD method. The detailed specifications provided by the vendor are listed in Table 1

  3. Hydrodynamical model and experimental results of a calcium looping cycle for CO2 capture

    International Nuclear Information System (INIS)

    Lisbona, Pilar; Martínez, Ana; Romeo, Luis M.

    2013-01-01

    Highlights: ► A scaled experimental cold flow model of a dual fluidized bed facility is presented. ► Two MATLAB models are developed for the single CFB and the dual CFB facility. ► Set of experiments are carried out and used to validate the mathematical model. ► Good agreement between model and experimental tests for sCFB. ► Further work required for validating dual CFB operation. -- Abstract: High temperature looping cycles involving solid circulation, such as carbonation–calcination, play an essential role among the CO 2 capture technologies under development. The low cost and high availability of Ca-based sorbents together with the feasibility of integration between these capture systems and existing power plants lead to very competitive potential costs of avoided CO 2 , below 20 €/tonne. Optimal configurations make use of several interconnected fluidized beds. One promising configuration for Ca-based sorbents looping systems relies on the use of two circulating beds (carbonator and calciner) and two bubbling beds acting as non-mechanical valves. Fluidized beds are well characterized when operating independently since they are extensively used in industrial applications, power and chemical plants. However, the operation when two or more fluidized beds exchange solid material through non-mechanical valves is still uncertain because of the more complex pressure balance of the system. Theoretical studies based on thermo-chemical simulations and experimental studies show that minimum CO 2 capture cost is attained with large solid circulation flow between reactors. The challenge is to reach the required particle circulation in a system with a complex configuration and be able to control it. Solid internal recirculation in any of these fluidized beds would provide flexibility in its control but it will also make harder the characterization of the whole system. The aim of this work is to analyse the hydrodynamics of the system and to generate a

  4. Abatement of CO2 emissions by way of enhancing the efficiency of nuclear power plants

    International Nuclear Information System (INIS)

    Kienle, F.

    1995-01-01

    Contributing about one third of the overall electricity supplied by the public utilities in 1994, nuclear power as in the previous years has been one of the major pillars of electricity supply in Germany. The approx. 150 billion kWh generated by the nuclear power plants represent reliable electricity supply around the clock, and free of CO 2 emissions, or SO 2 emissions, or NO x . Comparing nuclear generation with the electricity output contributed by conventional power plants in Germany, nuclear generation can also be expressed in terms of emissions avoided, which in 1994 meant: almost 150 million tons of CO 2 , equivalent to about 16 % of the aggregate annual CO 2 emissions; 110.000 tons of SO 2 , equivalent to about 11 % of aggregate annual SO 2 emissions; 125.000 tons of NO x , equivalent to 5 % of aggregate, annual NO x emissions. (orig.) [de

  5. Life cycle assessment of grid-connected photovoltaic power generation from crystalline silicon solar modules in China

    International Nuclear Information System (INIS)

    Hou, Guofu; Sun, Honghang; Jiang, Ziying; Pan, Ziqiang; Wang, Yibo; Zhang, Xiaodan; Zhao, Ying; Yao, Qiang

    2016-01-01

    Graphical abstract: Comparison of life cycle GHG emissions of various power sources. - Highlights: • The LCA study of grid-connected PV generation with silicon solar modules in China has been performed. • The energy payback times range from 1.6 to 2.3 years. • The GHG emissions are in the range of 60.1–87.3 g-CO_2,eq/kW h. • The PV manufacturing process occupied about 85% or higher of total energy usage and total GHG emission. • The SoG-Si production process accounted for more than 35% of total energy consumption and GHG emissions. - Abstract: The environmental impacts of grid-connected photovoltaic (PV) power generation from crystalline silicon (c-Si) solar modules in China have been investigated using life cycle assessment (LCA). The life cycle inventory was first analyzed. Then the energy consumption and greenhouse gas (GHG) emission during every process were estimated in detail, and finally the life-cycle value was calculated. The results showed that the energy payback time (T_E_P_B_T) of grid-connected PV power with crystalline silicon solar modules ranges from 1.6 to 2.3 years, while the GHG emissions now range from 60.1 to 87.3 g-CO_2,eq/kW h depending on the installation methods. About 84% or even more of the total energy consumption and total GHG emission occupied during the PV manufacturing process. The solar grade silicon (SoG-Si) production is the most energy-consuming and GHG-emitting process, which accounts for more than 35% of the total energy consumption and the total GHG emission. The results presented in this study are expected to provide useful information to enact reasonable policies, development targets, as well as subsidies for PV technology in China.

  6. SAGD CO2 mitigation through energy efficiency improvements

    International Nuclear Information System (INIS)

    Plessis du, D.

    2010-01-01

    An evaluation of the carbon dioxide (CO 2 ) emissions reductions achieved using energy efficiency measures in steam assisted gravity drainage (SAGD) operations was presented. The efficiency of a typical SAGD operation was analyzed using an indexing tool based on the Carnot cycle efficiency to develop an ideal SAGD heat cycle. The benefits of using an organic Rankine cycle (ORC) technology to convert waste heat to electrical power were also investigated. A CO 2 abatement curve was used to identify the economic benefits and costs of various greenhouse gas (GHG) reductions. The level of recovered energy was determined in relation to energy prices, capital costs, and carbon penalties in order to determine the most efficient means of decreasing energy usage. The study demonstrated that energy efficiency can be improved by up to 20 percent, and water loss reductions of up to 50 percent can be achieved using cost-effective energy efficiency measures. Results of the study can be used to guide government policy and provide industry with practical tools to benchmark performance and improve efficiencies. 4 refs., 1 tab., 10 figs.

  7. Flexible asymmetric supercapacitors based upon Co9S8 nanorod//Co3O4@RuO2 nanosheet arrays on carbon cloth.

    Science.gov (United States)

    Xu, Jing; Wang, Qiufan; Wang, Xiaowei; Xiang, Qingyi; Liang, Bo; Chen, Di; Shen, Guozhen

    2013-06-25

    We have successfully fabricated flexible asymmetric supercapacitors (ASCs) based on acicular Co9S8 nanorod arrays as positive materials and Co3O4@RuO2 nanosheet arrays as negative materials on woven carbon fabrics. Co9S8 nanorod arrays were synthesized by a hydrothermal sulfuration treatment of acicular Co3O4 nanorod arrays, while the RuO2 was directly deposited on the Co3O4 nanorod arrays. Carbon cloth was selected as both the substrate and the current collector for its good conductivity, high flexibility, good physical strength, and lightweight architecture. Both aqueous KOH solutions and polyvinyl alcohol (PVA)/KOH were employed as electrolyte for electrochemical measurements. The as-fabricated ASCs can be cycled reversibly in the range of 0-1.6 V and exhibit superior electrochemical performance with an energy density of 1.21 mWh/cm(3) at a power density of 13.29 W/cm(3) in aqueous electrolyte and an energy density of 1.44 mWh/cm(3) at the power density of 0.89 W/cm(3) in solid-state electrolyte, which are almost 10-fold higher than those reported in early ASC work. Moreover, they present excellent cycling performance at multirate currents and large currents after thousands of cycles. The high-performance nanostructured ASCs have significant potential applications in portable electronics and electrical vehicles.

  8. CO.sub.2 removal sorbent composition with high chemical stability during multiple cycles

    Science.gov (United States)

    Siriwardane, Ranjani V.; Rosencwaig, Shira

    2015-09-22

    Disclosed herein is a clay-alkali-amine CO.sub.2 sorbent composition prepared by integrating a clay substrate, basic alkali salt, and amine liquid. The basic alkali salt is present relative to the clay substrate in a weight ratio of from about 1 part to about 50 parts per 100 parts of the clay substrate. The amine liquid is present relative to a clay-alkali combination in a weight ratio of from about 1 part to about 10 parts per 10 parts of the clay-alkali combination. The clay-alkali-amine C02 sorbent is particularly advantageous for low temperature CO.sub.2 removal cycles in a gas stream having a C02 concentration less than around 2000 ppm and an oxygen concentration around 21%, such as air.

  9. Τhe observational and empirical thermospheric CO2 and NO power do not exhibit power-law behavior; an indication of their reliability

    Science.gov (United States)

    Varotsos, C. A.; Efstathiou, M. N.

    2018-03-01

    In this paper we investigate the evolution of the energy emitted by CO2 and NO from the Earth's thermosphere on a global scale using both observational and empirically derived data. In the beginning, we analyze the daily power observations of CO2 and NO received from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) equipment on the NASA Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite for the entire period 2002-2016. We then perform the same analysis on the empirical daily power emitted by CO2 and NO that were derived recently from the infrared energy budget of the thermosphere during 1947-2016. The tool used for the analysis of the observational and empirical datasets is the detrended fluctuation analysis, in order to investigate whether the power emitted by CO2 and by NO from the thermosphere exhibits power-law behavior. The results obtained from both observational and empirical data do not support the establishment of the power-law behavior. This conclusion reveals that the empirically derived data are characterized by the same intrinsic properties as those of the observational ones, thus enhancing the validity of their reliability.

  10. Technology of discharge and laser resonators for high power CO2 lasers. Koshutsuryoku CO2 laser ni tsukawareru hoden reiki laser kyoshinki gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Takenaka, Y.; Kuzumoto, M. (Mitsubishi Electric Corp., Tokyo (Japan))

    1994-03-20

    This paper describes discharge excitation technology and resonator technology as basic technologies for high power CO2 lasers. As a result of progress in high-frequency power element techniques, the discharge excitation technology now generally uses laser excitation using AC discharge of capacity coupling type. Its representative example is silent discharge (SD) excitation. This is a system to excite laser by applying high voltages with as high frequency as 100 kHz to 1 MHz across a pair of electrodes covered with a dielectric material. The system maintains stability in discharge even if power supply voltage amplitude is modulated, and easily provides pulse outputs. Discharge excitation for diffusion cooled type CO2 laser generates a discharge in a gap with a gap length of about 2 mm, and can perform gas cooling by means of thermal conduction of gas, whereas a compact resonator can be fabricated. A resonator for the diffusion cooled type CO2 laser eliminates gas circulation and cooling systems, hence the device can be made more compact. A report has been given that several of these compact resonators were combined, from which a laser output of 85W was obtained by using RF discharge of 2kW. 43 refs., 21 figs.

  11. Preliminary Design of Supercritical CO{sub 2} Radial Turbine for Micro Modular Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seong Kuk; Lee, Jekyoung; Kim, Seong Gu; Lee, Jeong Ik [KAIST (Korea, Republic of); Cha, Jae Eun [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The KAIST research team suggested an innovative concept of SMR called KAIST Micro Modular Reactor (MMR). It is aimed for achieving complete modularization of a nuclear power plant including the Power Conversion Unit (PCU) for simple transportation and installation. In consideration of the maintenance, S-CO{sub 2} has superior characteristic to the light water because it is less corrosive. Table I represents summary of the main design results of KAIST MMR. As such efforts the study on S-CO{sub 2} turbomachinery has been actively conducted because the S-CO{sub 2} Brayton cycle operates under extreme conditions such as high rotational speed, high pressure, and dramatic change of thermodynamic properties near the critical point (30.98 .deg. C, 7377kPa). To achieve higher thermal efficiency, the operation near the critical point is prerequisite in the S-CO{sub 2} Brayton cycle. For these reasons, research works on the S-CO{sub 2} turbomachinery naturally have been focused on the compressor which operates near the critical point. Due to the absence of loss models in S-CO{sub 2} field, loss models with air turbine were first utilized to design and predict the off design performance of a S-CO{sub 2} turbine. To check propriety of the code logic the code results compared with experimental data measured in air condition. The predicted values showed good agreement with the experiment data. Lastly, performance maps for S-CO{sub 2} turbine for the MMR were generated with change of mass flow rate and rotational speed.

  12. Nuclear power and the nuclear fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1976-07-01

    The IAEA is organizing a major conference on nuclear power and the nuclear fuel cycle, which is to be held from 2 to 13 May 1977 in Salzburg, Austria. The programme for the conference was published in the preceding issue of the IAEA Bulletin (Vol.18, No. 3/4). Topics to be covered at the conference include: world energy supply and demand, supply of nuclear fuel and fuel cycle services, radioactivity management (including transport), nuclear safety, public acceptance of nuclear power, safeguarding of nuclear materials, and nuclear power prospects in developing countries. The articles in the section that follows are intended to serve as an introduction to the topics to be discussed at the Salzburg Conference. They deal with the demand for uranium and nuclear fuel cycle services, uranium supplies, a computer simulation of regional fuel cycle centres, nuclear safety codes, management of radioactive wastes, and a pioneering research project on factors that determine public attitudes toward nuclear power. It is planned to present additional background articles, including a review of the world nuclear fuel reprocessing situation and developments in the uranium enrichment industry, in future issues of the Bulletin. (author)

  13. A Life Cycle Assessment Case Study of Coal-Fired Electricity Generation with Humidity Swing Direct Air Capture of CO2 versus MEA-Based Postcombustion Capture.

    Science.gov (United States)

    van der Giesen, Coen; Meinrenken, Christoph J; Kleijn, René; Sprecher, Benjamin; Lackner, Klaus S; Kramer, Gert Jan

    2017-01-17

    Most carbon capture and storage (CCS) envisions capturing CO 2 from flue gas. Direct air capture (DAC) of CO 2 has hitherto been deemed unviable because of the higher energy associated with capture at low atmospheric concentrations. We present a Life Cycle Assessment of coal-fired electricity generation that compares monoethanolamine (MEA)-based postcombustion capture (PCC) of CO 2 with distributed, humidity-swing-based direct air capture (HS-DAC). Given suitable temperature, humidity, wind, and water availability, HS-DAC can be largely passive. Comparing energy requirements of HS-DAC and MEA-PCC, we find that the parasitic load of HS-DAC is less than twice that of MEA-PCC (60-72 kJ/mol versus 33-46 kJ/mol, respectively). We also compare other environmental impacts as a function of net greenhouse gas (GHG) mitigation: To achieve the same 73% mitigation as MEA-PCC, HS-DAC would increase nine other environmental impacts by on average 38%, whereas MEA-PCC would increase them by 31%. Powering distributed HS-DAC with photovoltaics (instead of coal) while including recapture of all background GHG, reduces this increase to 18%, hypothetically enabling coal-based electricity with net-zero life-cycle GHG. We conclude that, in suitable geographies, HS-DAC can complement MEA-PCC to enable CO 2 capture independent of time and location of emissions and recapture background GHG from fossil-based electricity beyond flue stack emissions.

  14. Hydrogen production from coal gasification for effective downstream CO{sub 2} capture

    Energy Technology Data Exchange (ETDEWEB)

    Gnanapragasam, Nirmal V.; Reddy, Bale V.; Rosen, Marc A. [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario, L1H 7K4 (Canada)

    2010-05-15

    The coal gasification process is used in commercial production of synthetic gas as a means toward clean use of coal. The conversion of solid coal into a gaseous phase creates opportunities to produce more energy forms than electricity (which is the case in coal combustion systems) and to separate CO{sub 2} in an effective manner for sequestration. The current work compares the energy and exergy efficiencies of an integrated coal-gasification combined-cycle power generation system with that of coal gasification-based hydrogen production system which uses water-gas shift and membrane reactors. Results suggest that the syngas-to-hydrogen (H{sub 2}) system offers 35% higher energy and 17% higher exergy efficiencies than the syngas-to-electricity (IGCC) system. The specific CO{sub 2} emission from the hydrogen system was 5% lower than IGCC system. The Brayton cycle in the IGCC system draws much nitrogen after combustion along with CO{sub 2}. Thus CO{sub 2} capture and compression become difficult due to the large volume of gases involved, unlike the hydrogen system which has 80% less nitrogen in its exhaust stream. The extra electrical power consumption for compressing the exhaust gases to store CO{sub 2} is above 70% for the IGCC system but is only 4.5% for the H{sub 2} system. Overall the syngas-to-hydrogen system appears advantageous to the IGCC system based on the current analysis. (author)

  15. Forecasting global atmospheric CO2

    International Nuclear Information System (INIS)

    Agusti-Panareda, A.; Massart, S.; Boussetta, S.; Balsamo, G.; Beljaars, A.; Engelen, R.; Jones, L.; Peuch, V.H.; Chevallier, F.; Ciais, P.; Paris, J.D.; Sherlock, V.

    2014-01-01

    A new global atmospheric carbon dioxide (CO 2 ) real-time forecast is now available as part of the preoperational Monitoring of Atmospheric Composition and Climate - Interim Implementation (MACC-II) service using the infrastructure of the European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecasting System (IFS). One of the strengths of the CO 2 forecasting system is that the land surface, including vegetation CO 2 fluxes, is modelled online within the IFS. Other CO 2 fluxes are prescribed from inventories and from off-line statistical and physical models. The CO 2 forecast also benefits from the transport modelling from a state-of-the-art numerical weather prediction (NWP) system initialized daily with a wealth of meteorological observations. This paper describes the capability of the forecast in modelling the variability of CO 2 on different temporal and spatial scales compared to observations. The modulation of the amplitude of the CO 2 diurnal cycle by near-surface winds and boundary layer height is generally well represented in the forecast. The CO 2 forecast also has high skill in simulating day-to-day synoptic variability. In the atmospheric boundary layer, this skill is significantly enhanced by modelling the day-to-day variability of the CO 2 fluxes from vegetation compared to using equivalent monthly mean fluxes with a diurnal cycle. However, biases in the modelled CO 2 fluxes also lead to accumulating errors in the CO 2 forecast. These biases vary with season with an underestimation of the amplitude of the seasonal cycle both for the CO 2 fluxes compared to total optimized fluxes and the atmospheric CO 2 compared to observations. The largest biases in the atmospheric CO 2 forecast are found in spring, corresponding to the onset of the growing season in the Northern Hemisphere. In the future, the forecast will be re-initialized regularly with atmospheric CO 2 analyses based on the assimilation of CO 2 products retrieved from satellite

  16. Costs of solar and wind power variability for reducing CO2 emissions.

    Science.gov (United States)

    Lueken, Colleen; Cohen, Gilbert E; Apt, Jay

    2012-09-04

    We compare the power output from a year of electricity generation data from one solar thermal plant, two solar photovoltaic (PV) arrays, and twenty Electric Reliability Council of Texas (ERCOT) wind farms. The analysis shows that solar PV electricity generation is approximately one hundred times more variable at frequencies on the order of 10(-3) Hz than solar thermal electricity generation, and the variability of wind generation lies between that of solar PV and solar thermal. We calculate the cost of variability of the different solar power sources and wind by using the costs of ancillary services and the energy required to compensate for its variability and intermittency, and the cost of variability per unit of displaced CO(2) emissions. We show the costs of variability are highly dependent on both technology type and capacity factor. California emissions data were used to calculate the cost of variability per unit of displaced CO(2) emissions. Variability cost is greatest for solar PV generation at $8-11 per MWh. The cost of variability for solar thermal generation is $5 per MWh, while that of wind generation in ERCOT was found to be on average $4 per MWh. Variability adds ~$15/tonne CO(2) to the cost of abatement for solar thermal power, $25 for wind, and $33-$40 for PV.

  17. CO2 content of electricity losses

    International Nuclear Information System (INIS)

    Daví-Arderius, Daniel; Sanin, María-Eugenia; Trujillo-Baute, Elisa

    2017-01-01

    Countries are implementing policies to develop greener energy markets worldwide. In Europe, the ¨2030 Energy and Climate Package¨ asks for further reductions of green house gases, renewable sources integration, and energy efficiency targets. But the polluting intensity of electricity may be different in average than when considering market inefficiencies, in particular losses, and therefore the implemented policy must take those differences into account. Precisely, herein we study the importance in terms of CO2 emissions the extra amount of energy necessary to cover losses. With this purpose we use Spanish market and system data with hourly frequency from 2011 to 2013. Our results show that indeed electricity losses significantly explain CO2 emissions, with a higher CO2 emissions rate when covering losses than the average rate of the system. Additionally, we find that the market closing technologies used to cover losses have a positive and significant impact on CO2 emissions: when polluting technologies (coal or combined cycle) close the market, the impact of losses on CO2 emissions is high compared to the rest of technologies (combined heat and power, renewables or hydropower). To the light of these results we make some policy recommendations to reduce the impact of losses on CO2 emissions. - Highlights: • Electricity losses significantly explain CO2 emissions. • Policies aimed to reducing losses have a positive impact on CO2 emissions. • The market closing technology used to cover losses have impacts on CO2 emissions. • Pollutant technologies that close the market should be replaced by renewables.

  18. 1D Ni-Co oxide and sulfide nanoarray/carbon aerogel hybrid nanostructures for asymmetric supercapacitors with high energy density and excellent cycling stability.

    Science.gov (United States)

    Hao, Pin; Tian, Jian; Sang, Yuanhua; Tuan, Chia-Chi; Cui, Guanwei; Shi, Xifeng; Wong, C P; Tang, Bo; Liu, Hong

    2016-09-15

    The fabrication of supercapacitor electrodes with high energy density and excellent cycling stability is still a great challenge. A carbon aerogel, possessing a hierarchical porous structure, high specific surface area and electrical conductivity, is an ideal backbone to support transition metal oxides and bring hope to prepare electrodes with high energy density and excellent cycling stability. Therefore, NiCo 2 S 4 nanotube array/carbon aerogel and NiCo 2 O 4 nanoneedle array/carbon aerogel hybrid supercapacitor electrode materials were synthesized by assembling Ni-Co precursor needle arrays on the surface of the channel walls of hierarchical porous carbon aerogels derived from chitosan in this study. The 1D nanostructures grow on the channel surface of the carbon aerogel vertically and tightly, contributing to the enhanced electrochemical performance with ultrahigh energy density. The energy density of NiCo 2 S 4 nanotube array/carbon aerogel and NiCo 2 O 4 nanoneedle array/carbon aerogel hybrid asymmetric supercapacitors can reach up to 55.3 Wh kg -1 and 47.5 Wh kg -1 at a power density of 400 W kg -1 , respectively. These asymmetric devices also displayed excellent cycling stability with a capacitance retention of about 96.6% and 92% over 5000 cycles.

  19. Development of power plant emissions of NO{sub 2} and CO{sub 2}; Entwicklung der Kraftwerksemissionen bei NO{sub 2} und CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Friede, H.; Rosenbauer, G. [Siemens AG Power Generation, Erlangen (Germany)

    2007-07-01

    In the future energy demand will further increase. Therefore it will be necessary to use also minor fuel qualities. More effort for fuel preparation and flue gas cleaning will be necessary. Some disadvantages may be minimised with new technologies, e.g. integrated gasification combined cycle, fuel change and fuel preparation. Hugh improvements are already achieved in regard to the emissions of the classical components CO, VOC, NOx, SO{sub 2}, Particulate Matter and Mercury. More progress can be expected with optimisation of existing technologies, especially DeNOx-catalysis, catalysis for oxidation of CO and VOC, flue gas desulfurisation, bathhouse filters and electrostatic filters for the reduction of PM and Mercury assisted by adsorbers. Important is a kind of emission limit flexibility, a contribution to the security of supply while using renewable energies and lifetime optimisation. More and more emphasis is put on cost/benefit considerations for a better environment. Measures for CO{sub 2}-Reduction need plant screening and for the efficient exhaust emission reduction fair play in trading emission certificates. (orig.)

  20. Enhancing Catalyzed Decomposition of Na2CO3 with Co2MnO x Nanowire-Decorated Carbon Fibers for Advanced Na-CO2 Batteries.

    Science.gov (United States)

    Fang, Cong; Luo, Jianmin; Jin, Chengbin; Yuan, Huadong; Sheng, Ouwei; Huang, Hui; Gan, Yongping; Xia, Yang; Liang, Chu; Zhang, Jun; Zhang, Wenkui; Tao, Xinyong

    2018-05-23

    The metal-CO 2 batteries, especially Na-CO 2 , batteries come into sight owing to their high energy density, ability for CO 2 capture, and the abundance of sodium resource. Besides the sluggish electrochemical reactions at the gas cathodes and the instability of the electrolyte at a high voltage, the final discharge product Na 2 CO 3 is a solid and poor conductor of electricity, which may cause the high overpotential and poor cycle performance for the Na-CO 2 batteries. The promotion of decomposition of Na 2 CO 3 should be an efficient strategy to enhance the electrochemical performance. Here, we design a facile Na 2 CO 3 activation experiment to screen the efficient cathode catalyst for the Na-CO 2 batteries. It is found that the Co 2 MnO x nanowire-decorated carbon fibers (CMO@CF) can promote the Na 2 CO 3 decomposition at the lowest voltage among all these metal oxide-decorated carbon fiber structures. After assembling the Na-CO 2 batteries, the electrodes based on CMO@CF show lower overpotential and better cycling performance compared with the electrodes based on pristine carbon fibers and other metal oxide-modified carbon fibers. We believe this catalyst screening method and the freestanding structure of the CMO@CF electrode may provide an important reference for the development of advanced Na-CO 2 batteries.

  1. Hydrate-based technology for CO2 capture from fossil fuel power plants

    International Nuclear Information System (INIS)

    Yang, Mingjun; Song, Yongchen; Jiang, Lanlan; Zhao, Yuechao; Ruan, Xuke; Zhang, Yi; Wang, Shanrong

    2014-01-01

    Graphical abstract: Application of hydrate based technology on carbon dioxide capture and storage (CCS). - Highlights: • Hydrate-based CO 2 –N 2 separation data was obtained for flow in porous media. • Tetrahydrofuran and sodium dodecyl sulphate are used as additives simultaneously. • Solution movement rarely occurs when residual solution saturations are low. • Bothe of pressure and temperature have remarkable impacts on gas compositions. • A suitable operation parameter choice is proposed for hydrate-based CO 2 capture. - Abstract: Hydrate-based CO 2 capture is a promising technology. To obtain fundamental data for a flowing system, we measured the distribution of pore solution to analyse hydrate formation/dissociation and gas separation properties. An orthogonal experiment was carried out to investigate the effects of glass beads, flow rates, pressures and temperatures on it. Magnetic resonance imaging (MRI) images were obtained using a spin echo multi-slice pulse sequence. Hydrate saturations were calculated quantitatively using an MRI mean intensity. The results show that hydrate blockages were frequently present. During the hydrate formation and dissociation process, the movement of the solution occurred in cycles. However, the solution movement rarely occurred for residual solution saturations obtained with a high backpressure. The solution concentrate phenomenon occurred mostly in BZ-04. The highest hydrate saturation was 30.2%, and the lowest was 0.70%. Unlike that in BZ-01, there was no stability present in BZ-02 and BZ-04. The different CO 2 concentrations for the three processes of each cycle verified hydrate formation during the gas flow process. The highest CO 2 concentration was 38.8%, and the lowest one was 11.4%. To obtain high hydrate saturation and good separation effects, the values of 5.00 MPa, 1.0 ml min −1 and 280.00 K were chosen. For the gas flow process, only the pressure had a significant impact on gas composition, and all

  2. CO/sub 2/, carbon cycle and climate interactions. Pt. 2

    Energy Technology Data Exchange (ETDEWEB)

    Grassl, H; Maier-Reimer, E; Degens, E T; Kempe, S; Spitzy, A

    1984-05-01

    To assess the reaction of the climate system on increased CO/sub 2/ in the air either numerical atmospheric models have been used, or one has tried to filter a CO/sub 2/-induced climate trend (such as increasing temperature) from existing meteorological records. Even though a serious effect of increased CO/sub 2/ on climate has become highly probable, it has neither been empirically proven so far (diagnosis of observations) nor is the effect theoretically undisputed (prognosis by climate models).

  3. The potential role of nuclear power in controlling CO2 emissions

    International Nuclear Information System (INIS)

    Fulkerson, W.; Jones, J.E.; Delene, J.G.; Perry, A.M.; Cantor, R.A.

    1990-01-01

    Nuclear power currently reduces CO 2 emissions from fossil fuel burning worldwide by about 8% (0.4 Gt(C)/yr). It can continue to play an important role only if it can grow substantially in the next 50 years. For such growth to occur public confidence will need to improve throughout the world. That might happen if (a) other non-fossil alternatives are inadequate to meet electricity demand growth, (b) the risks to society from global warming are perceived to be very high, (c) nuclear technology improves substantially, and (d) an international institutional setting is devised to manage the nuclear enterprise so that the technology is available to all nations while catastrophic accidents and proliferation of nuclear weapon capabilities are avoided. It seems feasible that the necessary technological and institutional advances can be devised and tested over the next 20 years. It is also plausible that the direct costs of electricity produced by the system would be in the range of 50-100 mills/kWhr (1990 dollars) delivered to the grid. In other words, the direct costs of nuclear power should not be greater than they are today. Achieving such an outcome will require aggressive technical and institutional RD ampersand D performed in a cooperative international setting. If rapid growth of nuclear power can begin again in 15-20 years it could supply 30-50% of world electricity in 50 years and cut CO 2 emission rates by up to 2.5 Gt(C)/yr. This would be a substantial contribution to controlling greenhouse gases, but it is not sufficient. Improved efficiency and various renewable energy sources must also grow rapidly if CO 2 emission rates from electricity generation are to be reduced from the current value of about 2 Gt(C)/yr. 41 refs., 4 figs., 3 tabs

  4. Implications of the recent reductions in natural gas prices for emissions of CO2 from the US power sector.

    Science.gov (United States)

    Lu, Xi; Salovaara, Jackson; McElroy, Michael B

    2012-03-06

    CO(2) emissions from the US power sector decreased by 8.76% in 2009 relative to 2008 contributing to a decrease over this period of 6.59% in overall US emissions of greenhouse gases. An econometric model, tuned to data reported for regional generation of US electricity, is used to diagnose factors responsible for the 2009 decrease. More than half of the reduction is attributed to a shift from generation of power using coal to gas driven by a recent decrease in gas prices in response to the increase in production from shale. An important result of the model is that, when the cost differential for generation using gas rather than coal falls below 2-3 cents/kWh, less efficient coal fired plants are displaced by more efficient natural gas combined cycle (NGCC) generation alternatives. Costs for generation using NGCC decreased by close to 4 cents/kWh in 2009 relative to 2008 ensuring that generation of electricity using gas was competitive with coal in 2009 in contrast to the situation in 2008 when gas prices were much higher. A modest price on carbon could contribute to additional switching from coal to gas with further savings in CO(2) emissions.

  5. Variability in soil CO2 production and surface CO2 efflux across riparian-hillslope transitions

    Science.gov (United States)

    Vincent Jerald. Pacific

    2007-01-01

    The spatial and temporal controls on soil CO2 production and surface CO2 efflux have been identified as an outstanding gap in our understanding of carbon cycling. I investigated both the spatial and temporal variability of soil CO2 concentrations and surface CO2 efflux across eight topographically distinct riparian-hillslope transitions in the ~300 ha subalpine upper-...

  6. Factors affecting CO2 emission from the power sector of selected countries in Asia and the Pacific

    International Nuclear Information System (INIS)

    Shrestha, Ram M.; Anandarajah, Gabrial; Liyanage, Migara H.

    2009-01-01

    This study analyzes the key factors behind the CO 2 emissions from the power sector in fifteen selected countries in Asia and the Pacific using the Log-Mean Divisia Index method of decomposition. The roles of changes in economic output, electricity intensity of the economy, fuel intensity of power generation and generation structure are examined in the evolution of CO 2 emission from the power sector of the selected countries during 1980-2004. The study shows that the economic growth was the dominant factor behind the increase in CO 2 emission in ten of the selected countries (i.e., Australia, China, India, Japan, Malaysia, Pakistan, South Korea, Singapore, Thailand and Vietnam, while the increasing electricity intensity of the economy was the main factor in three countries (Bangladesh, Indonesia and Philippines). Structural changes in power generation were found to be the main contributor to changes in the CO 2 emission in the case of Sri Lanka and New Zealand.

  7. Effects of tillage practice and atmospheric CO2 level on soil CO2 efflux

    Science.gov (United States)

    Elevated atmospheric carbon dioxide (CO2) affects both the quantity and quality of plant tissues, which impacts the cycling and storage of carbon (C) within plant/soil systems and thus the rate of CO2 release back to the atmosphere. Research to accurately quantify the effects of elevated CO2 and as...

  8. Report of fiscal 1999 basic survey for promoting joint implementation, etc. Combined cycle power generation project for Surgut No.1 power station in the Russian Federation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    This paper explains fiscal 1999 survey on a combined cycle power generation project for Surgut power plant in the Russian Federation for the purpose of making the project tied to the COP3 joint implementation. This power plant consists of 16 units with the total capacity of 3,300 MW. This project is to replace the existing superannuated No.1 through No.6 units with a new high-efficiency gas combined cycle power plant. The project plant is planned to comprise of three units, having the capacity of 417 MW, each consisting of one gas turbine and one steam turbine. The average generation efficiency will be improved tremendously from the present 37.2% to 55.2%. The initial investment will be 615 million in US dollars (at 109.2 yen/dollar). Energy saving will be 634,800 toe/year, with cost to effect 9,452 toe-y/million yen. Greenhouse effect gas reduction will be 1,509,000 t-CO2/year, with cost to effect 22.5 t-CO2-y/million yen. The investment recovery period is estimated to be 24 years. The Russian side strongly wishes to be granted a finance on a favorable terms and conditions to realize this project. It is possible that the Russian government requests Japan for grant of the Yen credit. Accordingly, an early start is necessary in order to deal with such request. (NEDO)

  9. Power-Generation Characteristics After Vibration and Thermal Stresses of Thermoelectric Unicouples with CoSb3/Ti/Mo(Cu) Interfaces

    Science.gov (United States)

    Bae, Kwang Ho; Choi, Soon-Mok; Kim, Kyung-Hun; Choi, Hyoung-Seuk; Seo, Won-Seon; Kim, Il-Ho; Lee, Soonil; Hwang, Hae Jin

    2015-06-01

    Reliability tests for thermoelectric unicouples were carried out to investigate the adhesion properties of CoSb3/Ti/Mo(Cu) interfaces. The n-type In0.25 Co3.95Ni0.05Sb12 and p-type In0.25Co3FeSb12 bulks were prepared for fabricating a thermoelectric unicouple (one p- n couple) by an induction melting and a spark plasma sintering process. Mo-Cu alloy was selected as an electrode for the unicouples due to its high melting temperature and proper work function value. Many thermoelectric unicouples with the CoSb3/Ti/Mo(Cu) interfaces were fabricated with the proper brazing materials by means of a repeated firing process. Reliability of the unicouples with the interfaces was evaluated by a vibration test and a thermal cycling test. After the thermal cycling and vibration tests, the power-generation characteristics of the unicouples were compared with the unicouples before the tests. Even after the vibration test, electrical power with a power density of 0.5 W/cm2 was generated. The Ti-interlayer is considered as a possible candidate for making a reliable unicouple with high adhesion strength. With the thermal cycling test, the resistance of the unicouple increased and the electrical power from the unicouple decreased. A failure mode by the thermal cycling test was ascribed to a complex effect of micro-cracks originated from the thermal stress and oxidation problem of the thermoelectric materials; that is, a thick oxide layer more than 300 μm was detected after a high-temperature durability test of n-type In0.25Co3.95Ni0.05Sb12 material at 773 K in air for 7 days.

  10. Fast power cycle for fusion reactors

    International Nuclear Information System (INIS)

    Powell, J.; Fillo, J.; Makowitz, H.

    1978-01-01

    The unique, deep penetration capability of 14 MeV neutrons produced in DT fusion reactions allows the generation of very high temperature working fluid temperatures in a thermal power cycle. In the FAST (Fusion Augmented Steam Turbine) power cycle steam is directly superheated by the high temperature ceramic refractory interior of the blanket, after being generated by heat extracted from the relatively cool blanket structure. The steam is then passed to a high temperature gas turbine for power generation. Cycle studies have been carried out for a range of turbine inlet temperatures [1600 0 F to 3000 0 F (870 to 1650 0 C)], number of reheats, turbine mechanical efficiency, recuperator effectiveness, and system pressure losses. Gross cycle efficiency is projected to be in the range of 55 to 60%, (fusion energy to electric power), depending on parameters selected. Turbine inlet temperatures above 2000 0 F, while they do increase efficiency somewhat, are not necessarily for high cycle efficiency

  11. Network Theory Integrated Life Cycle Assessment for an Electric Power System

    Directory of Open Access Journals (Sweden)

    Heetae Kim

    2015-08-01

    Full Text Available In this study, we allocate Greenhouse gas (GHG emissions of electricity transmission to the consumers. As an allocation basis, we introduce energy distance. Energy distance takes the transmission load on the electricity energy system into account in addition to the amount of electricity consumption. As a case study, we estimate regional GHG emissions of electricity transmission loss in Chile. Life cycle assessment (LCA is used to estimate the total GHG emissions of the Chilean electric power system. The regional GHG emission of transmission loss is calculated from the total GHG emissions. We construct the network model of Chilean electric power grid as an undirected network with 466 nodes and 543 edges holding the topology of the power grid based on the statistical record. We analyze the total annual GHG emissions of the Chilean electricity energy system as 23.07 Mt CO2-eq. and 1.61 Mt CO2-eq. for the transmission loss, respectively. The total energy distance for the electricity transmission accounts for 12,842.10 TWh km based on network analysis. We argue that when the GHG emission of electricity transmission loss is estimated, the electricity transmission load should be separately considered. We propose network theory as a useful complement to LCA analysis for the complex allocation. Energy distance is especially useful on a very large-scale electric power grid such as an intercontinental transmission network.

  12. Thermodynamic analysis of vapor compression heat pump cycle for tap water heating and development of CO_2 heat pump water heater for residential use

    International Nuclear Information System (INIS)

    Saikawa, Michiyuki; Koyama, Shigeru

    2016-01-01

    Highlights: • The ideal vapor compression cycle for tap water heating and its COP were defined. • It was verified theoretically that CO_2 achieves the highest COP for tap water heating. • The prototype of CO_2 heat pump water heater for residential use was developed. • Further COP improvement of CO_2 heat pump water heater was estimated. - Abstract: The ideal vapor compression cycle for tap water heating and its coefficient of performance (COP) have been studied theoretically at first. The ideal cycle is defined as the cycle whose high temperature heat source varies temperature with constant specific heat and other processes are same as the reverse Carnot cycle. The COP upper limit of single stage compression heat pump cycle for tap water heating with various refrigerants such as fluorocarbons and natural refrigerants was calculated. The refrigerant which achieves the highest COP for supplying hot water is CO_2. Next, the prototype of CO_2 heat pump water heater for residential use has been developed. Its outline and experimental results are described. Finally its further possibility of COP improvement has been studied. The COP considered a limit from a technical point of view was estimated about 6.0 at the Japanese shoulder season (spring and autumn) test condition of heating water from 17 °C to 65 °C at 16 °C heat source air temperature (dry bulb)/12 °C (wet bulb).

  13. Energy implications of future stabilization of atmospheric CO2 content

    International Nuclear Information System (INIS)

    Hoffert, M.I.; Jain, A.K.

    1998-01-01

    The United Nations Framework Convention on Climate Change calls for ''stabilization of greenhouse-gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system...''. A standard baseline scenario that assumes no policy intervention to limit greenhouse-gas emissions has 10 TW (10 x 10 12 watts) of carbon-emission-free power being produced by the year 2050, equivalent to the power provided by all today's energy sources combined. Here we employ a carbon-cycle/energy model to estimate the carbon-emission-free power needed for various atmospheric CO 2 stabilization scenarios. We find that CO 2 stabilization with continued economic growth will require innovative, cost-effective and carbon-emission-free technologies that can provide additional tens of terawatts of primary power in the coming decades, and certainly by the middle of the twenty-first century, even with sustained improvement in the economic productivity of primary energy. (author)

  14. Enhancing power cycle efficiency for a supercritical Brayton cycle power system using tunable supercritical gas mixtures

    Science.gov (United States)

    Wright, Steven A.; Pickard, Paul S.; Vernon, Milton E.; Radel, Ross F.

    2017-08-29

    Various technologies pertaining to tuning composition of a fluid mixture in a supercritical Brayton cycle power generation system are described herein. Compounds, such as Alkanes, are selectively added or removed from an operating fluid of the supercritical Brayton cycle power generation system to cause the critical temperature of the fluid to move up or down, depending upon environmental conditions. As efficiency of the supercritical Brayton cycle power generation system is substantially optimized when heat is rejected near the critical temperature of the fluid, dynamically modifying the critical temperature of the fluid based upon sensed environmental conditions improves efficiency of such a system.

  15. Reduction of CO2 emission by INCAM model in Malaysia biomass power plants during the year 2016.

    Science.gov (United States)

    Amin, Nor Aishah Saidina; Talebian-Kiakalaieh, Amin

    2018-03-01

    As the world's second largest palm oil producer and exporter, Malaysia could capitalize on its oil palm biomass waste for power generation. The emission factors from this renewable energy source are far lower than that of fossil fuels. This study applies an integrated carbon accounting and mitigation (INCAM) model to calculate the amount of CO 2 emissions from two biomass thermal power plants. The CO 2 emissions released from biomass plants utilizing empty fruit bunch (EFB) and palm oil mill effluent (POME), as alternative fuels for powering steam and gas turbines, were determined using the INCAM model. Each section emitting CO 2 in the power plant, known as the carbon accounting center (CAC), was measured for its carbon profile (CP) and carbon index (CI). The carbon performance indicator (CPI) included electricity, fuel and water consumption, solid waste and waste-water generation. The carbon emission index (CEI) and carbon emission profile (CEP), based on the total monthly carbon production, were determined across the CPI. Various innovative strategies resulted in a 20%-90% reduction of CO 2 emissions. The implementation of reduction strategies significantly reduced the CO 2 emission levels. Based on the model, utilization of EFB and POME in the facilities could significantly reduce the CO 2 emissions and increase the potential for waste to energy initiatives. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. LMTD Design Methodology Assessment of Spiral Tube Heat Exchanger under the S-CO{sub 2} cycle operating condition

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hwa Young; Lee, Jeong Ik; Ahn, Yoon Han [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2013-05-15

    The advantages of PCHE are compact high pressure difference endurance high temperature operation. However, PCHE is quite expensive and the resistance to the fast thermal cycling is questionable. In order to overcome this problem, the Korea Advanced Institute of Science and Technology (KAIST) research team is considering an alternative for the PCHE. Currently KAIST research team is using a Spiral Tube Heat Exchanger (STHE) of Sentry Equipment Corp. as a pre cooler in the SCO{sub 2}PE facility. A STHE is relatively cheap but the operating pressure and temperature are acceptable for utilizing it as a pre cooler. A STHE is consisted of spiral shaped tubes (hot side i.e. S-CO{sub 2}) immersed in a shell (cold side i.e. water). This study is aimed at whether the logarithmic mean temperature difference (LMTD) heat exchanger design methodology is acceptable for designing the S-CO{sub 2} cycle pre cooler. This is because the LMTD method usually assumes a constant specific heat, but the pre cooler in the S-CO{sub 2} cycle operates at the nearest point to the critical point where a dramatic change in properties is expected. Experimentally obtained data are compared to the vendor provided technical specification based on the LMTD method. The detailed specifications provided by the vendor are listed in Table 1.

  17. The Arctic Ocean marine carbon cycle: evaluation of air-sea CO2 exchanges, ocean acidification impacts and potential feedbacks

    Directory of Open Access Journals (Sweden)

    N. R. Bates

    2009-11-01

    Full Text Available At present, although seasonal sea-ice cover mitigates atmosphere-ocean gas exchange, the Arctic Ocean takes up carbon dioxide (CO2 on the order of −66 to −199 Tg C year−1 (1012 g C, contributing 5–14% to the global balance of CO2 sinks and sources. Because of this, the Arctic Ocean has an important influence on the global carbon cycle, with the marine carbon cycle and atmosphere-ocean CO2 exchanges sensitive to Arctic Ocean and global climate change feedbacks. In the near-term, further sea-ice loss and increases in phytoplankton growth rates are expected to increase the uptake of CO2 by Arctic Ocean surface waters, although mitigated somewhat by surface warming in the Arctic. Thus, the capacity of the Arctic Ocean to uptake CO2 is expected to alter in response to environmental changes driven largely by climate. These changes are likely to continue to modify the physics, biogeochemistry, and ecology of the Arctic Ocean in ways that are not yet fully understood. In surface waters, sea-ice melt, river runoff, cooling and uptake of CO2 through air-sea gas exchange combine to decrease the calcium carbonate (CaCO3 mineral saturation states (Ω of seawater while seasonal phytoplankton primary production (PP mitigates this effect. Biological amplification of ocean acidification effects in subsurface waters, due to the remineralization of organic matter, is likely to reduce the ability of many species to produce CaCO3 shells or tests with profound implications for Arctic marine ecosystems

  18. Noncircular Chainrings Do Not Influence Maximum Cycling Power.

    Science.gov (United States)

    Leong, Chee-Hoi; Elmer, Steven J; Martin, James C

    2017-12-01

    Noncircular chainrings could increase cycling power by prolonging the powerful leg extension/flexion phases, and curtailing the low-power transition phases. We compared maximal cycling power-pedaling rate relationships, and joint-specific kinematics and powers across 3 chainring eccentricities (CON = 1.0; LOW ecc  = 1.13; HIGH ecc  = 1.24). Part I: Thirteen cyclists performed maximal inertial-load cycling under 3 chainring conditions. Maximum cycling power and optimal pedaling rate were determined. Part II: Ten cyclists performed maximal isokinetic cycling (120 rpm) under the same 3 chainring conditions. Pedal and joint-specific powers were determined using pedal forces and limb kinematics. Neither maximal cycling power nor optimal pedaling rate differed across chainring conditions (all p > .05). Peak ankle angular velocity for HIGH ecc was less than CON (p pedal system allowed cyclists to manipulate ankle angular velocity to maintain their preferred knee and hip actions, suggesting maximizing extension/flexion and minimizing transition phases may be counterproductive for maximal power.

  19. Origin of the Reductive Tricarboxylic Acid (rTCA Cycle-Type CO2 Fixation: A Perspective

    Directory of Open Access Journals (Sweden)

    Norio Kitadai

    2017-10-01

    Full Text Available The reductive tricarboxylic acid (rTCA cycle is among the most plausible candidates for the first autotrophic metabolism in the earliest life. Extant enzymes fixing CO2 in this cycle contain cofactors at the catalytic centers, but it is unlikely that the protein/cofactor system emerged at once in a prebiotic process. Here, we discuss the feasibility of non-enzymatic cofactor-assisted drive of the rTCA reactions in the primitive Earth environments, particularly focusing on the acetyl-CoA conversion to pyruvate. Based on the energetic and mechanistic aspects of this reaction, we propose that the deep-sea hydrothermal vent environments with active electricity generation in the presence of various sulfide catalysts are a promising setting for it to progress. Our view supports the theory of an autotrophic origin of life from primordial carbon assimilation within a sulfide-rich hydrothermal vent.

  20. Valuation of marginal CO2 abatement options for electric power plants in Korea

    International Nuclear Information System (INIS)

    Park, Hojeong; Lim, Jaekyu

    2009-01-01

    The electricity generation sector in Korea is under pressure to mitigate greenhouse gases as directed by the Kyoto Protocol. The principal compliance options for power companies under the cap-and-trade include the application of direct CO 2 emission abatement and the procurement of emission allowances. The objective of this paper is to provide an analytical framework for assessing the cost-effectiveness of these options. We attempt to derive the marginal abatement cost for CO 2 using the output distance function and analyze the relative advantages of emission allowance procurement option as compared to direct abatement option. Real-option approach is adopted to incorporate emission allowance price uncertainty. Empirical result shows the marginal abatement cost with an average of Euro 14.04/ton CO 2 for fossil-fueled power plants and confirms the existence of substantial cost heterogeneity among plants which is sufficient to achieve trading gains in allowance market. The comparison of two options enables us to identify the optimal position of the compliance for each plant. Sensitivity analyses are also presented with regard to several key parameters including the initial allowance prices and interest rate. The result of this paper may help Korean power plants to prepare for upcoming regulations targeted toward the reduction of domestic greenhouse gases.

  1. A comparative analysis of rankine and absorption power cycles from exergoeconomic viewpoint

    International Nuclear Information System (INIS)

    Shokati, Naser; Ranjbar, Faramarz; Yari, Mortaza

    2014-01-01

    Highlights: • The Rankine and absorption power cycles are compared from exergoeconomic viewpoint. • The LiBr–H 2 O cycle has the highest unit cost of electricity produced by turbine. • The LiBr–H 2 O cycle has the lowest exergy destruction cost rate. • In LiBr–H 2 O cycle, the generator has the maximum value regarding (C-dot) D,k +(C-dot) L,k +(Z-dot) k . - Abstract: In this paper LiBr–H 2 O and NH 3 –H 2 O absorption power cycles and Rankine cycle which produce 1 MW electrical power in same conditions of heat sources are compared from exergoeconomic point of view. Exergoeconomic analysis is performed using the specific exergy costing (SPECO) method. The results show that among these cycles, although the LiBr–H 2 O cycle has the highest first law efficiency, but unit cost of electricity produced by turbine for LiBr–H 2 O cycle is more than that for Rankine cycle. This value is lowest for the NH 3 –H 2 O cycle. Moreover, the NH 3 –H 2 O cycle has the highest and the LiBr–H 2 O cycle has the lowest exergy destruction cost rate. The generator, the absorber and the boiler in all considered cycles have the maximum value of sum of cost rate associated with capital investment, operating and maintenance, exergy destruction and exergy losses. Therefore, these components should be taken into consideration from exergoeconomic viewpoint. In parametric study, it is observed that in the constant generator temperature, as the generator pressure increases, unit cost of power produced by turbine for LiBr–H 2 O and Rankine cycles decreases. This value for Rankine cycle is lower than for LiBr–H 2 O cycle whereas Rankine cycle efficiency is less than the efficiency of LiBr–H 2 O cycle. Also, in LiBr–H 2 O cycle, at constant temperature of the generator, the value of exergy destruction cost rate is minimized and exergoeconomic factor is maximized at particular values of generator pressure and the more absorber pressure results the minimum value of

  2. A novel nuclear combined power and cooling system integrating high temperature gas-cooled reactor with ammonia–water cycle

    International Nuclear Information System (INIS)

    Luo, Chending; Zhao, Fuqiang; Zhang, Na

    2014-01-01

    Highlights: • We propose a novel nuclear ammonia–water power and cooling cogeneration system. • The high temperature reactor is inherently safe, with exhaust heat fully recovered. • The thermal performances are improved compared with nuclear combined cycle. • The base case attains an energy efficiency of 69.9% and exergy efficiency of 72.5%. • Energy conservation and emission reduction are achieved in this cogeneration way. - Abstract: A nuclear ammonia–water power and refrigeration cogeneration system (NAPR) has been proposed and analyzed in this paper. It consists of a closed high temperature gas-cooled reactor (HTGR) topping Brayton cycle and a modified ammonia water power/refrigeration combined bottoming cycle (APR). The HTGR is an inherently safe reactor, and thus could be stable, flexible and suitable for various energy supply situation, and its exhaust heat is fully recovered by the mixture of ammonia and water in the bottoming cycle. To reduce exergy losses and enhance outputs, the ammonia concentrations of the bottoming cycle working fluid are optimized in both power and refrigeration processes. With the HTGR of 200 MW thermal capacity and 900 °C/70 bar reactor-core-outlet helium, the system achieves 88.8 MW net electrical output and 9.27 MW refrigeration capacity, and also attains an energy efficiency of 69.9% and exergy efficiency of 72.5%, which are higher by 5.3%-points and 2.6%-points as compared with the nuclear combined cycle (NCC, like a conventional gas/steam power-only combined cycle while the topping cycle is a closed HTGR Brayton cycle) with the same nuclear energy input. Compared with conventional separate power and refrigeration generation systems, the fossil fuel saving (based on CH 4 ) and CO 2 emission reduction of base-case NAPR could reach ∼9.66 × 10 4 t/y and ∼26.6 × 10 4 t/y, respectively. The system integration accomplishes the safe and high-efficiency utilization of nuclear energy by power and refrigeration

  3. Metal corrosion in a supercritical carbon dioxide - liquid sodium power cycle.

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Robert Charles; Conboy, Thomas M.

    2012-02-01

    A liquid sodium cooled fast reactor coupled to a supercritical carbon dioxide Brayton power cycle is a promising combination for the next generation nuclear power production process. For optimum efficiency, a microchannel heat exchanger, constructed by diffusion bonding, can be used for heat transfer from the liquid sodium reactor coolant to the supercritical carbon dioxide. In this work, we have reviewed the literature on corrosion of metals in liquid sodium and carbon dioxide. The main conclusions are (1) pure, dry CO{sub 2} is virtually inert but can be highly corrosive in the presence of even ppm concentrations of water, (2) carburization and decarburization are very significant mechanism for corrosion in liquid sodium especially at high temperature and the mechanism is not well understood, and (3) very little information could be located on corrosion of diffusion bonded metals. Significantly more research is needed in all of these areas.

  4. Extension of the supercritical carbon dioxide brayton cycle to low reactor power operation: investigations using the coupled anl plant dynamics code-SAS4A/SASSYS-1 liquid metal reactor code system

    International Nuclear Information System (INIS)

    Moisseytsev, A.; Sienicki, J.J.

    2012-01-01

    Significant progress has been made on the development of a control strategy for the supercritical carbon dioxide (S-CO 2 ) Brayton cycle enabling removal of power from an autonomous load following Sodium-Cooled Fast Reactor (SFR) down to decay heat levels such that the S-CO 2 cycle can be used to cool the reactor until decay heat can be removed by the normal shutdown heat removal system or a passive decay heat removal system such as Direct Reactor Auxiliary Cooling System (DRACS) loops with DRACS in-vessel heat exchangers. This capability of the new control strategy eliminates the need for use of a separate shutdown heat removal system which might also use supercritical CO 2 . It has been found that this capability can be achieved by introducing a new control mechanism involving shaft speed control for the common shaft joining the turbine and two compressors following reduction of the load demand from the electrical grid to zero. Following disconnection of the generator from the electrical grid, heat is removed from the intermediate sodium circuit through the sodium-to-CO 2 heat exchanger, the turbine solely drives the two compressors, and heat is rejected from the cycle through the CO 2 -to-water cooler. To investigate the effectiveness of shaft speed control, calculations are carried out using the coupled Plant Dynamics Code-SAS4A/SASSYS-1 code for a linear load reduction transient for a 1000 MWt metallic-fueled SFR with autonomous load following. No deliberate motion of control rods or adjustment of sodium pump speeds is assumed to take place. It is assumed that the S-CO 2 turbomachinery shaft speed linearly decreases from 100 to 20% nominal following reduction of grid load to zero. The reactor power is calculated to autonomously decrease down to 3% nominal providing a lengthy window in time for the switchover to the normal shutdown heat removal system or for a passive decay heat removal system to become effective. However, the calculations reveal that the

  5. Power plant cycle chemistry - a currently neglected power plant chemistry discipline

    International Nuclear Information System (INIS)

    Bursik, A.

    2005-01-01

    Power plant cycle chemistry seems to be a stepchild at both utilities and universities and research organizations. It is felt that other power plant chemistry disciplines are more important. The last International Power Cycle Chemistry Conference in Prague may be cited as an example. A critical review of the papers presented at this conference seems to confirm the above-mentioned statements. This situation is very unsatisfactory and has led to an increasing number of component failures and instances of damage to major cycle components. Optimization of cycle chemistry in fossil power plants undoubtedly results in clear benefits and savings with respect to operating costs. It should be kept in mind that many seemingly important chemistry-related issues lose their importance during forced outages of units practicing faulty plant cycle chemistry. (orig.)

  6. An Asymmetric Supercapacitor with Mesoporous NiCo2O4 Nanorod/Graphene Composite and N-Doped Graphene Electrodes

    Science.gov (United States)

    Mao, J. W.; He, C. H.; Qi, J. Q.; Zhang, A. B.; Sui, Y. W.; He, Y. Z.; Meng, Q. K.; Wei, F. X.

    2018-01-01

    In the present work, mesoporous NiCo2O4 nanorod/graphene oxide (NiCo2O4/GO) composite was prepared by a facile and cost-effective hydrothermal method and meanwhile, N-doped graphene (N-G) was fabricated also by a hydrothermal synthesis process. NiCo2O4/GO composite and N-G were used as positive and negative electrodes for the supercapacitor, respectively, which all displayed excellent electrochemical performances. The NiCo2O4/GO composite electrode exhibited a high specific capacitance of 709.7 F g-1 at a current density of 1 A g-1 and excellent rate capability as well as good cycling performance with 84.7% capacitance retention at 6 A g-1 after 3000 cycles. A high-voltage asymmetric supercapacitor (ASC) was successfully fabricated using NiCo2O4/GO composite and N-G as the positive and negative electrodes, respectively, in 1 M KOH aqueous electrolyte. The ASC delivered a high energy density of 34.4 Wh kg-1 at a power density of 800 W kg-1 and still maintained 28 Wh kg-1 at a power density of 8000 W kg-1. Furthermore, this ASC showed excellent cycling stability with 94.3% specific capacitance retained at 5 A g-1 after 5000 cycles. The impressive results can be ascribed to the positive synergistic effects of the two electrodes. Evidently, our work provides useful information for assembling high-performance supercapacitor devices.

  7. Forecasting Responses of a Northern Peatland Carbon Cycle to Elevated CO2 and a Gradient of Experimental Warming

    Science.gov (United States)

    Jiang, Jiang; Huang, Yuanyuan; Ma, Shuang; Stacy, Mark; Shi, Zheng; Ricciuto, Daniel M.; Hanson, Paul J.; Luo, Yiqi

    2018-03-01

    The ability to forecast ecological carbon cycling is imperative to land management in a world where past carbon fluxes are no longer a clear guide in the Anthropocene. However, carbon-flux forecasting has not been practiced routinely like numerical weather prediction. This study explored (1) the relative contributions of model forcing data and parameters to uncertainty in forecasting flux- versus pool-based carbon cycle variables and (2) the time points when temperature and CO2 treatments may cause statistically detectable differences in those variables. We developed an online forecasting workflow (Ecological Platform for Assimilation of Data (EcoPAD)), which facilitates iterative data-model integration. EcoPAD automates data transfer from sensor networks, data assimilation, and ecological forecasting. We used the Spruce and Peatland Responses Under Changing Experiments data collected from 2011 to 2014 to constrain the parameters in the Terrestrial Ecosystem Model, forecast carbon cycle responses to elevated CO2 and a gradient of warming from 2015 to 2024, and specify uncertainties in the model output. Our results showed that data assimilation substantially reduces forecasting uncertainties. Interestingly, we found that the stochasticity of future external forcing contributed more to the uncertainty of forecasting future dynamics of C flux-related variables than model parameters. However, the parameter uncertainty primarily contributes to the uncertainty in forecasting C pool-related response variables. Given the uncertainties in forecasting carbon fluxes and pools, our analysis showed that statistically different responses of fast-turnover pools to various CO2 and warming treatments were observed sooner than slow-turnover pools. Our study has identified the sources of uncertainties in model prediction and thus leads to improve ecological carbon cycling forecasts in the future.

  8. Insight into the Global Carbon Cycle from Assimilation of Satellite CO2 measurements

    Science.gov (United States)

    Baker, D. F.

    2017-12-01

    A key goal of satellite CO2 measurements is to provide sufficient spatio-temporal coverage to constrain portions of the globe poorly observed by the in situ network, especially the tropical land regions. While systematic errors in both measurements and modeling remain a challenge, these satellite data are providing new insight into the functioning of the global carbon cycle, most notably across the recent 2015-16 En Niño. Here we interpret CO2 measurements from the GOSAT and OCO-2 satellites, as well as from the global in situ network (both surface sites and routine aircraft profiles), using a 4DVar-based global CO2 flux inversion across 2009-2017. The GOSAT data indicate that the tropical land regions are responsible for most of the observed global variability in CO2 across the last 8+ years. For the most recent couple of years where they overlap, the OCO-2 data give the same result, an +2 PgC/yr shift towards CO2 release in the ENSO warm phase, while disagreeing somewhat on the absolute value of the flux. The variability given by both these satellites disagrees with that given by an in situ-only inversion across the recent 2015-16 El Niño: the +2 PgC/yr shift from the satellites is double that given by the in situ data alone, suggesting that the more complete coverage is providing a more accurate view. For the current release of OCO-2 data (version 7), however, the flux results given by the OCO-2 land data (from both nadir- and glint-viewing modes) disagree significantly with those given by the ocean glint data; we examine the soon-to-be-released v8 data to assess whether these systematic retrieval errors have been reduced, and whether the corrected OCO-2 ocean data support the result from the land data. We discuss finer-scale features flux results given by the satellite data, and examine the importance of the flux prior, as well.

  9. Is it only CO{sub 2} that matters? A life cycle perspective on shallow geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Saner, Dominik; Juraske, Ronnie; Hellweg, Stefanie [Group for Ecological Systems Design, Institute of Environmental Engineering, ETH Zurich, Schafmattstrasse 6, CH-8093 Zurich (Switzerland); Kuebert, Markus [Systherma GmbH, Am Haag 12, D-72181 Starzach-Felldorf (Germany); Blum, Philipp [Karlsruhe Institute of Technology (KIT), Institute for Applied Geosciences (AGW), Kaiserstrasse 12, D-76131 Karlsruhe (Germany); Bayer, Peter [Engineering Geology, Geological Institute, ETH Zurich, Sonneggstrasse 5, CH-8092 Zurich (Switzerland)

    2010-09-15

    Shallow geothermal systems such as open and closed geothermal heat pump (GHP) systems are considered to be an efficient and renewable energy technology for cooling and heating of buildings and other facilities. The numbers of installed ground source heat pump (GSHP) systems, for example, is continuously increasing worldwide. The objective of the current study is not only to discuss the net energy consumption and greenhouse gas (GHG) emissions or savings by GHP operation, but also to fully examine environmental burdens and benefits related to applications of such shallow geothermal systems by employing a state-of the-art life cycle assessment (LCA). The latter enables us to assess the entire energy flows and resources use for any product or service that is involved in the life cycle of such a technology. The applied life cycle impact assessment methodology (ReCiPe 2008) shows the relative contributions of resources depletion (34%), human health (43%) and ecosystem quality (23%) of such GSHP systems to the overall environmental damage. Climate change, as one impact category among 18 others, contributes 55.4% to the total environmental impacts. The life cycle impact assessment also demonstrates that the supplied electricity for the operation of the heat pump is the primary contributor to the environmental impact of GSHP systems, followed by the heat pump refrigerant, production of the heat pump, transport, heat carrier liquid, borehole and borehole heat exchanger (BHE). GHG emissions related to the use of such GSHP systems are carefully reviewed; an average of 63 t CO{sub 2} equivalent emissions is calculated for a life cycle of 20 years using the Continental European electricity mix with 0.599 kg CO{sub 2} eq/kWh. However, resulting CO{sub 2} eq savings for Europe, which are between -31% and 88% in comparison to conventional heating systems such as oil fired boilers and gas furnaces, largely depend on the primary resource of the supplied electricity for the heat pump

  10. Co(OH)2/RGO/NiO sandwich-structured nanotube arrays with special surface and synergistic effects as high-performance positive electrodes for asymmetric supercapacitors

    Science.gov (United States)

    Xu, Han; Zhang, Chi; Zhou, Wen; Li, Gao-Ren

    2015-10-01

    High power density, high energy density and excellent cycling stability are the main requirements for high-performance supercapacitors (SCs) that will be widely used for portable consumer electronics and hybrid electric vehicles. Here we investigate novel types of hybrid Co(OH)2/reduced graphene oxide (RGO)/NiO sandwich-structured nanotube arrays (SNTAs) as positive electrodes for asymmetric supercapacitors (ASCs). The synthesized Co(OH)2/RGO/NiO SNTAs exhibit a significantly improved specific capacity (~1470 F g-1 at 5 mV s-1) and excellent cycling stability with ~98% Csp retention after 10 000 cycles because of the fast transport and short diffusion paths for electroactive species, the high utilization rate of electrode materials, and special synergistic effects among Co(OH)2, RGO, and NiO. The high-performance ASCs are assembled using Co(OH)2/RGO/NiO SNTAs as positive electrodes and active carbon (AC) as negative electrodes, and they exhibit a high energy density (115 Wh kg-1), a high power density (27.5 kW kg-1) and an excellent cycling stability (less 5% Csp loss after 10 000 cycles). This study shows an important breakthrough in the design and fabrication of multi-walled hybrid nanotube arrays as positive electrodes for ASCs.High power density, high energy density and excellent cycling stability are the main requirements for high-performance supercapacitors (SCs) that will be widely used for portable consumer electronics and hybrid electric vehicles. Here we investigate novel types of hybrid Co(OH)2/reduced graphene oxide (RGO)/NiO sandwich-structured nanotube arrays (SNTAs) as positive electrodes for asymmetric supercapacitors (ASCs). The synthesized Co(OH)2/RGO/NiO SNTAs exhibit a significantly improved specific capacity (~1470 F g-1 at 5 mV s-1) and excellent cycling stability with ~98% Csp retention after 10 000 cycles because of the fast transport and short diffusion paths for electroactive species, the high utilization rate of electrode materials, and

  11. Diffusion-cooled high-power single-mode waveguide CO2 laser for transmyocardial revascularization

    Science.gov (United States)

    Berishvili, I. I.; Bockeria, L. A.; Egorov, E. N.; Golubev, Vladimir S.; Galushkin, Michail G.; Kheliminsky, A. A.; Panchenko, Vladislav Y.; Roshin, A. P.; Sigaev, I. Y.; Vachromeeva, M. N.; Vasiltsov, Victor V.; Yoshina, V. I.; Zabelin, Alexandre M.; Zelenov, Evgenii V.

    1999-01-01

    The paper presents the results on investigations and development of multichannel waveguide CO2 laser with diffusion cooling of active medium excited by discharge of audio-frequency alternating current. The description of high-power single-mode CO2 laser with average beam power up to 1 kW is presented. The result of measurement of the laser basic parameters are offered, as well as the outcomes of performances of the laser head with long active zone, operating in waveguide mode. As an example of application of these laser, various capabilities a description of the developed medical system 'Genom' used in the transmyocardial laser revascularization (TMLR) procedure and clinical results of the possibilities of the TMLR in the surgical treatment are presented.

  12. Biological CO2 mitigation from coal power plant by Chlorella fusca and Spirulina sp.

    Science.gov (United States)

    Duarte, Jessica Hartwig; de Morais, Etiele Greque; Radmann, Elisângela Martha; Costa, Jorge Alberto Vieira

    2017-06-01

    CO 2 biofixation by microalgae and cyanobacteria is an environmentally sustainable way to mitigate coal burn gas emissions. In this work the microalga Chlorella fusca LEB 111 and the cyanobacteria Spirulina sp. LEB 18 were cultivated using CO 2 from coal flue gas as a carbon source. The intermittent flue gas injection in the cultures enable the cells growth and CO 2 biofixation by these microorganisms. The Chlorella fusca isolated from a coal power plant could fix 2.6 times more CO 2 than Spirulina sp. The maximum daily CO 2 from coal flue gas biofixation was obtained with Chlorella fusca (360.12±0.27mgL -1 d -1 ), showing a specific growth rate of 0.17±<0.01d -1 . The results demonstrated the Chlorella fusca LEB 111 and Spirulina sp. LEB 18 potential to fix CO 2 from coal flue gas, and sequential biomass production with different biotechnological destinations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Soil Conditions Rather Than Long-Term Exposure to Elevated CO2 Affect Soil Microbial Communities Associated with N-Cycling

    Directory of Open Access Journals (Sweden)

    Kristof Brenzinger

    2017-10-01

    Full Text Available Continuously rising atmospheric CO2 concentrations may lead to an increased transfer of organic C from plants to the soil through rhizodeposition and may affect the interaction between the C- and N-cycle. For instance, fumigation of soils with elevated CO2 (eCO2 concentrations (20% higher compared to current atmospheric concentrations at the Giessen Free-Air Carbon Dioxide Enrichment (GiFACE sites resulted in a more than 2-fold increase of long-term N2O emissions and an increase in dissimilatory reduction of nitrate compared to ambient CO2 (aCO2. We hypothesized that the observed differences in soil functioning were based on differences in the abundance and composition of microbial communities in general and especially of those which are responsible for N-transformations in soil. We also expected eCO2 effects on soil parameters, such as on nitrate as previously reported. To explore the impact of long-term eCO2 on soil microbial communities, we applied a molecular approach (qPCR, T-RFLP, and 454 pyrosequencing. Microbial groups were analyzed in soil of three sets of two FACE plots (three replicate samples from each plot, which were fumigated with eCO2 and aCO2, respectively. N-fixers, denitrifiers, archaeal and bacterial ammonia oxidizers, and dissimilatory nitrate reducers producing ammonia were targeted by analysis of functional marker genes, and the overall archaeal community by 16S rRNA genes. Remarkably, soil parameters as well as the abundance and composition of microbial communities in the top soil under eCO2 differed only slightly from soil under aCO2. Wherever differences in microbial community abundance and composition were detected, they were not linked to CO2 level but rather determined by differences in soil parameters (e.g., soil moisture content due to the localization of the GiFACE sets in the experimental field. We concluded that +20% eCO2 had little to no effect on the overall microbial community involved in N-cycling in the

  14. Soil Conditions Rather Than Long-Term Exposure to Elevated CO2 Affect Soil Microbial Communities Associated with N-Cycling.

    Science.gov (United States)

    Brenzinger, Kristof; Kujala, Katharina; Horn, Marcus A; Moser, Gerald; Guillet, Cécile; Kammann, Claudia; Müller, Christoph; Braker, Gesche

    2017-01-01

    Continuously rising atmospheric CO 2 concentrations may lead to an increased transfer of organic C from plants to the soil through rhizodeposition and may affect the interaction between the C- and N-cycle. For instance, fumigation of soils with elevated CO 2 ( e CO 2 ) concentrations (20% higher compared to current atmospheric concentrations) at the Giessen Free-Air Carbon Dioxide Enrichment (GiFACE) sites resulted in a more than 2-fold increase of long-term N 2 O emissions and an increase in dissimilatory reduction of nitrate compared to ambient CO 2 ( a CO 2 ). We hypothesized that the observed differences in soil functioning were based on differences in the abundance and composition of microbial communities in general and especially of those which are responsible for N-transformations in soil. We also expected e CO 2 effects on soil parameters, such as on nitrate as previously reported. To explore the impact of long-term e CO 2 on soil microbial communities, we applied a molecular approach (qPCR, T-RFLP, and 454 pyrosequencing). Microbial groups were analyzed in soil of three sets of two FACE plots (three replicate samples from each plot), which were fumigated with e CO 2 and a CO 2 , respectively. N-fixers, denitrifiers, archaeal and bacterial ammonia oxidizers, and dissimilatory nitrate reducers producing ammonia were targeted by analysis of functional marker genes, and the overall archaeal community by 16S rRNA genes. Remarkably, soil parameters as well as the abundance and composition of microbial communities in the top soil under e CO 2 differed only slightly from soil under a CO 2 . Wherever differences in microbial community abundance and composition were detected, they were not linked to CO 2 level but rather determined by differences in soil parameters (e.g., soil moisture content) due to the localization of the GiFACE sets in the experimental field. We concluded that +20% e CO 2 had little to no effect on the overall microbial community involved in N-cycling

  15. SO{sub 2} retention by reactivated CaO-based sorbent from multiple CO{sub 2} capture cycles

    Energy Technology Data Exchange (ETDEWEB)

    Vasilije Manovic; Edward J. Anthony [CANMET Energy Technology Centre-Ottawa, Ottawa, ON (Canada). Natural Resources Canada

    2007-06-15

    This paper examines the reactivation of spent sorbent, produced from multiple CO{sub 2} capture cycles, for use in SO{sub 2} capture. CaO-based sorbent samples were obtained from Kelly Rock limestone using three particle size ranges, each containing different impurities levels. Using a thermogravimetric analyzer (TGA), the sulfation behavior of partially sulfated and unsulfated samples obtained after multiple calcination-carbonation cycles in a tube furnace (TF), following steam reactivation in a pressurized reactor, is examined. In addition, samples calcined/sintered under different conditions after hydration are also examined. The results show that suitably treated spent sorbent has better sulfation characteristics than that of the original sorbent. Thus for example, after 2 h sulfation, {gt} 80% of the CaO was sulfated. In addition, the sorbent showed significant activity even after 4 h when {gt} 95% CaO was sulfated. The results were confirmed by X-ray diffraction (XRD) analysis, which showed that, by the end of the sulfation process, samples contained CaSO{sub 4} with only traces of unreacted CaO. The superior behavior of spent reactivated sorbent appears to be due to swelling of the sorbent particles during steam hydration. The surface area morphology of sorbent after reactivation was examined by scanning electron microscopy (SEM). Ca(OH){sub 2} crystals were seen, which displayed their regular shape, and their elemental composition was confirmed by energy-dispersive X-ray (EDX) analysis. These results allow the proposal of a new process for the use of CaO-based sorbent in fluidized bed combustion (FBC) systems, which incorporates CO{sub 2} capture, sorbent reactivation, and SO{sub 2} retention. 26 refs., 4 figs., 2 tabs.

  16. Three-dimensional hierarchical NiCo2O4 nanowire@Ni3S2 nanosheet core/shell arrays for flexible asymmetric supercapacitors

    Science.gov (United States)

    Liu, Bo; Kong, Dezhi; Huang, Zhi Xiang; Mo, Runwei; Wang, Ye; Han, Zhaojun; Cheng, Chuanwei; Yang, Hui Ying

    2016-05-01

    Three-dimensional (3D) hierarchical NiCo2O4@Ni3S2 core/shell arrays on Ni foam were synthesized by a facile, stepwise synthesis approach. The 3D heterogeneous NiCo2O4 nanostructure forms an interconnected web-like scaffold and serves as the core for the Ni3S2 shell. The as-prepared NiCo2O4@Ni3S2 nanowire array (NWA) electrodes exhibited excellent electrochemical performance, such as high specific areal capacitance and excellent cycling stability. The specific areal capacitance of 3.0 F cm-2 at a current density of 5 mA cm-2 is among the highest values and the only 6.7% capacitance decay after 10 000 cycles demonstrates the excellent cycling stability. A flexible asymmetric supercapacitor (ASC) was fabricated with activated carbon (AC) as the anode and the obtained NiCo2O4@Ni3S2 NWAs as the cathode. The ASC device exhibited a high energy density of 1.89 mW h cm-3 at 5.81 W cm-3 and a high power density of 56.33 W cm-3 at 0.94 mW h cm-3. As a result, the hybrid nanoarchitecture opens a new way to design high performance electrodes for electrochemical energy storage applications.Three-dimensional (3D) hierarchical NiCo2O4@Ni3S2 core/shell arrays on Ni foam were synthesized by a facile, stepwise synthesis approach. The 3D heterogeneous NiCo2O4 nanostructure forms an interconnected web-like scaffold and serves as the core for the Ni3S2 shell. The as-prepared NiCo2O4@Ni3S2 nanowire array (NWA) electrodes exhibited excellent electrochemical performance, such as high specific areal capacitance and excellent cycling stability. The specific areal capacitance of 3.0 F cm-2 at a current density of 5 mA cm-2 is among the highest values and the only 6.7% capacitance decay after 10 000 cycles demonstrates the excellent cycling stability. A flexible asymmetric supercapacitor (ASC) was fabricated with activated carbon (AC) as the anode and the obtained NiCo2O4@Ni3S2 NWAs as the cathode. The ASC device exhibited a high energy density of 1.89 mW h cm-3 at 5.81 W cm-3 and a high power

  17. Effects of atmospheric CO2 enrichment on soil CO2 efflux in a young longleaf pine system

    Science.gov (United States)

    Elevated atmospheric carbon dioxide (CO2) can affect the quantity and quality of plant tissues which will impact carbon (C) cycling and storage in plant/soil systems and the release of CO2 back to the atmosphere. Research is needed to quantify the effects of elevated CO2 on soil CO2 efflux to predi...

  18. Strategies for development and CO2 abatement in China`s power industry

    Energy Technology Data Exchange (ETDEWEB)

    Ying, R.

    1996-12-31

    Chinese Government has set a series sustainable energy development policies and strategies to alleviate atmospheric pollution and to mitigate the CO2 emission. Some major policies and measures that will be emphasized in China`s power industrial development will be addressed in this paper.

  19. Electricity consumption and CO2 capture potential in Spain

    International Nuclear Information System (INIS)

    Romeo, Luis M.; Calvo, Elena; Valero, Antonio; De Vita, Alessia

    2009-01-01

    In this paper, different electricity demand scenarios for Spain are presented. Population, income per capita, energy intensity and the contribution of electricity to the total energy demand have been taken into account in the calculations. Technological role of different generation technologies, i.e. coal, nuclear, renewable, combined cycle (CC), combined heat and power (CHP) and carbon capture and storage (CCS), are examined in the form of scenarios up to 2050. Nine future scenarios corresponding to three electrical demands and three options for new capacity: minimum cost of electricity, minimum CO 2 emissions and a criterion with a compromise between CO 2 and cost (CO 2 -cost criterion) have been proposed. Calculations show reduction in CO 2 emissions from 2020 to 2030, reaching a maximum CO 2 emission reduction of 90% in 2050 in an efficiency scenario with CCS and renewables. The contribution of CCS from 2030 is important with percentage values of electricity production around 22-28% in 2050. The cost of electricity (COE) increases up to 25% in 2030, and then this value remains approximately constant or decreases slightly.

  20. Nuclear power and the carbon dioxide problem

    International Nuclear Information System (INIS)

    Bijlsma, J.J.; Blok, K.; Turkenburg, W.C.

    1989-05-01

    This study deals with the question, which contribution can be delivered by nuclear power to the redution of the emission of carbon dioxide (CO 2 ) from the power supply. The emphasis lays upon the following aspects: the emissions of CO 2 which occur in the nuclear-power cycle (the so-called indirect emission of CO 2 power plants); the amount of uranium stocks; the change of CO 2 emission caused by replacement of fossil fuels, in particular coal, by nuclear power. First an energy-analysis of the nuclear power cycle is presented. On the base of this analysis the CO 2 uranium can be calculated. The role of nuclear power in the reduction of CO 2 emission depends on the development of the final power demand. Therefore in this study two scenarios derived from the 'IIASA-low' scenario; 'low-energy'-scenario in which the world-energy consumption remains at about the same level. In the calculations the indirect emissions of CO 2 , also dependent on the ore richness and the technology used, have always been taken into account. In the calculations two uranium-reserve variants of resp. 5.7 and 30 mln. tons have been assumed. From the results of the calculations it can be concluded that whether or not taking account of the indirect emissions of CO 2 in the nuclear power cycle, has only limited effect on the calculated contribution of nuclear power to the solution of the greenhouse effect. The uranium reserves turn out to be determining for the potential contribution of nuclear power. By putting on the surely available reserve of 5.7 mln. tons, or the speculative reserve of 30 mln. tons, with the actual technology, an emission of resp. 130-140 billion and 880 billion tons CO 2 can be avoided in replacing coal. With maximal employment of improved conversion techniques these contributions may be doubled. (H.W.). 40 refs.; 13 figs.; 10 tabs

  1. Mode change of millennial CO2 variability during the last glacial cycle associated with a bipolar marine carbon seesaw.

    Science.gov (United States)

    Bereiter, Bernhard; Lüthi, Dieter; Siegrist, Michael; Schüpbach, Simon; Stocker, Thomas F; Fischer, Hubertus

    2012-06-19

    Important elements of natural climate variations during the last ice age are abrupt temperature increases over Greenland and related warming and cooling periods over Antarctica. Records from Antarctic ice cores have shown that the global carbon cycle also plays a role in these changes. The available data shows that atmospheric CO(2) follows closely temperatures reconstructed from Antarctic ice cores during these variations. Here, we present new high-resolution CO(2) data from Antarctic ice cores, which cover the period between 115,000 and 38,000 y before present. Our measurements show that also smaller Antarctic warming events have an imprint in CO(2) concentrations. Moreover, they indicate that during Marine Isotope Stage (MIS) 5, the peak of millennial CO(2) variations lags the onset of Dansgaard/Oeschger warmings by 250 ± 190 y. During MIS 3, this lag increases significantly to 870 ± 90 y. Considerations of the ocean circulation suggest that the millennial variability associated with the Atlantic Meridional Overturning Circulation (AMOC) undergoes a mode change from MIS 5 to MIS 4 and 3. Ocean carbon inventory estimates imply that during MIS 3 additional carbon is derived from an extended mass of carbon-enriched Antarctic Bottom Water. The absence of such a carbon-enriched water mass in the North Atlantic during MIS 5 can explain the smaller amount of carbon released to the atmosphere after the Antarctic temperature maximum and, hence, the shorter lag. Our new data provides further constraints for transient coupled carbon cycle-climate simulations during the entire last glacial cycle.

  2. The design and development of CO2 medium-level laser power calibration system for industrial and medical applications in Thailand

    Science.gov (United States)

    Nontapot, Kanokwan

    2018-03-01

    The carbon dioxide laser (CO2 laser) is one of the most useful and is the highest CW laser at the present. The laser produces infrared light at 10.6 um. Due to its high power, CO2 lasers are usually used in industrial applications such as cutting and welding, or for engraving at less power. CO2 lasers are also used widely in medical applications, such as laser surgery, skin resurfacing, and removing mold, due to water (biological tissue) absorb light at this wavelength very well. CO2 lasers are also used as LIDAR laser source for military range finding applications because of the transparency of the atmosphere to infrared light. Due to the increasing use of CO2 lasers laser in industrial and medical applications in Thailand, the National Institute of Metrology (Thailand) has set up a CO2 laser power calibration system and provide calibration service to customers this year. The service support calibration of medium-level laser power at wavelength of 10.6 um and at power range 100 mW-10W. The design and development of the calibration system will be presented.

  3. Industrial test and techno-economic analysis of CO2 capture in Huaneng Beijing coal-fired power station

    International Nuclear Information System (INIS)

    Huang, Bin; Xu, Shisen; Gao, Shiwang; Liu, Lianbo; Tao, Jiye; Niu, Hongwei; Cai, Ming; Cheng, Jian

    2010-01-01

    The first industrial-scale CO 2 capture plant in China has been demonstrated at Huaneng Beijing power plant has shown that this technology is a good option for the capture of CO 2 produced by commercial coal-fired power plants. The commissioning and industrial tests are introduced in this paper. The tests show that in the early stages of the passivation phase, the concentration variations of amine, anti-oxidant and Fe 3+ are in the normal range, and the main parameters achieve the design value. The efficiency of the CO 2 capture was about 80-85%, and by the end of January 2009 about 900 tons of CO 2 (99.7%) have been captured. The equipment investment and consumptive costs, including steam, power, solution and others, have been analyzed. The results show: the cost of the absorber and the stripper account for about 50% of main equipment; the consumptive cost is about 25.3 US$ per metric tons of CO 2 , of which the steam requirement accounts for about 55%; the COE increased by 0.02 US$/kW h and the electricity purchase price increased by 29%. (author)

  4. Parameter Sensitivity Study for Typical Expander-Based Transcritical CO2 Refrigeration Cycles

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2018-05-01

    Full Text Available A sensitivity study was conducted for three typical expander-based transcritical CO2 cycles with the developed simulation model, and the sensitivities of the maximum coefficient of performance (COP to the key operating parameters, including the inlet pressure of gas cooler, the temperatures at evaporator inlet and gas cooler outlet, the inter-stage pressure and the isentropic efficiency of expander, were obtained. The results showed that the sensitivity to the gas cooler inlet pressure differs greatly before and after the optimal gas cooler inlet pressure. The sensitivity to the intercooler outlet temperature in the two-stage cycles increases sharply to near zero and then keeps almost constant at intercooler outlet temperature of higher than 45 °C. However, the sensitivity stabilizes near zero when the evaporator inlet temperature is very low of −26.1 °C. In two-stage compression with an intercooler and an expander assisting in driving the first-stage compressor (TEADFC cycle, an abrupt change in the sensitivity of maximum COP to the inter-stage pressure was observed, but disappeared after intercooler outlet temperature exceeds 50 °C. The sensitivity of maximum COP to the expander isentropic efficiency increases almost linearly with the expander isentropic efficiency.

  5. The potential role of nuclear power in controlling CO sub 2 emissions

    Energy Technology Data Exchange (ETDEWEB)

    Fulkerson, W.; Jones, J.E.; Delene, J.G.; Perry, A.M.; Cantor, R.A.

    1990-01-01

    Nuclear power currently reduces CO{sub 2} emissions from fossil fuel burning worldwide by about 8% (0.4 Gt(C)/yr). It can continue to play an important role only if it can grow substantially in the next 50 years. For such growth to occur public confidence will need to improve throughout the world. That might happen if (a) other non-fossil alternatives are inadequate to meet electricity demand growth, (b) the risks to society from global warming are perceived to be very high, (c) nuclear technology improves substantially, and (d) an international institutional setting is devised to manage the nuclear enterprise so that the technology is available to all nations while catastrophic accidents and proliferation of nuclear weapon capabilities are avoided. It seems feasible that the necessary technological and institutional advances can be devised and tested over the next 20 years. It is also plausible that the direct costs of electricity produced by the system would be in the range of 50-100 mills/kWhr (1990 dollars) delivered to the grid. In other words, the direct costs of nuclear power should not be greater than they are today. Achieving such an outcome will require aggressive technical and institutional RD D performed in a cooperative international setting. If rapid growth of nuclear power can begin again in 15-20 years it could supply 30-50% of world electricity in 50 years and cut CO{sub 2} emission rates by up to 2.5 Gt(C)/yr. This would be a substantial contribution to controlling greenhouse gases, but it is not sufficient. Improved efficiency and various renewable energy sources must also grow rapidly if CO{sub 2} emission rates from electricity generation are to be reduced from the current value of about 2 Gt(C)/yr. 41 refs., 4 figs., 3 tabs.

  6. Three-Dimensional Hierarchical NixCo1-xO/NiyCo2-yP@C Hybrids on Nickel Foam for Excellent Supercapacitors.

    Science.gov (United States)

    Shao, Yubo; Zhao, Yongqing; Li, Hua; Xu, Cailing

    2016-12-28

    Active materials and special structures of the electrode have decisive influence on the electrochemical properties of supercapacitors. Herein, three-dimensional (3D) hierarchical Ni x Co 1-x O/Ni y Co 2-y P@C (denoted as NiCoOP@C) hybrids have been successfully prepared by a phosphorization treatment of hierarchical Ni x Co 1-x O@C grown on nickel foam. The resulting NiCoOP@C hybrids exhibit an outstanding specific capacitance and cycle performance because they couple the merits of the superior cycling stability of Ni x Co 1-x O, the high specific capacitance of Ni y Co 2-y P, the mechanical stability of carbon layer, and the 3D hierarchical structure. The specific capacitance of 2638 F g -1 can be obtained at the current density of 1 A g -1 , and even at the current density of 20 A g -1 , the NiCoOP@C electrode still possesses a specific capacitance of 1144 F g -1 . After 3000 cycles at 10 A g -1 , 84% of the initial specific capacitance is still remained. In addition, an asymmetric ultracapacitor (ASC) is assembled through using NiCoOP@C hybrids as anode and activated carbon as cathode. The as-prepared ASC obtains a maximum energy density of 39.4 Wh kg -1 at a power density of 394 W kg -1 and still holds 21 Wh kg -1 at 7500 W kg -1 .

  7. Perspectives of thermoelectric power generation in Brazil and Co2 emissions; Perspectivas da geracao termeletrica no Brasil e emissoes de Co2

    Energy Technology Data Exchange (ETDEWEB)

    Abdalad, Rogerio

    2000-03-01

    Climate changes taking place on Earth have a strong component due to energy, from the exploitation of primary sources and its conversion to end use forms. The overheating of the atmosphere is consequence of the increasing of greenhouse gases concentration with distinction to carbon dioxide - CO{sub 2}. Brazilian energy sector uses renewable sources with a intensity higher than the world average. The restructuring of the power sector adapting it to a competitive market might contribute to increase the use of fossil in the energy matrix - specially coal and natural gas. The development of thermal power generation technologies from fossil fuels supposes the adaptation to attend environmental patterns of CO{sub 2} emission rates. The improvement of the processes of thermal conversion of these fuels may, in midterm make economically feasible even the use of renewable sources such as biomass. The anticipation in the use of more efficient and advanced technologies has the characteristics of technical intervention and regulatory measures. This work analyses the effects of these actions and measures in a scenery with thermal power expansion in Brazil and estimates the amount of carbon dioxide emissions to a possible result to be achieved with anticipation of new technologies of thermal power using coal and natural gas. (author)

  8. The origin of methane and biomolecules from a CO2 cycle on terrestrial planets

    Czech Academy of Sciences Publication Activity Database

    Civiš, Svatopluk; Knížek, Antonín; Ivanek, Ondřej; Kubelík, Petr; Zukalová, Markéta; Kavan, Ladislav; Ferus, Martin

    2017-01-01

    Roč. 1, č. 10 (2017), s. 721-726 E-ISSN 2397-3366 R&D Projects: GA ČR GA17-05076S; GA ČR GA13-07724S Grant - others:Akademie věd - GA AV ČR(CZ) R200401721; Akademie věd - GA AV ČR(CZ) R200401521 Institutional support: RVO:61388955 Keywords : biomolecules * CO2 cycle on terrestrial planets * Mars Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry

  9. Evaluation of the Life Cycle Greenhouse Gas Emissions from Hydroelectricity Generation Systems

    Directory of Open Access Journals (Sweden)

    Akhil Kadiyala

    2016-06-01

    Full Text Available This study evaluated the life cycle greenhouse gas (GHG emissions from different hydroelectricity generation systems by first performing a comprehensive review of the hydroelectricity generation system life cycle assessment (LCA studies and then subsequent computation of statistical metrics to quantify the life cycle GHG emissions (expressed in grams of carbon dioxide equivalent per kilowatt hour, gCO2e/kWh. A categorization index (with unique category codes, formatted as “facility type-electric power generation capacity” was developed and used in this study to evaluate the life cycle GHG emissions from the reviewed hydroelectricity generation systems. The unique category codes were labeled by integrating the names of the two hydro power sub-classifications, i.e., the facility type (impoundment (I, diversion (D, pumped storage (PS, miscellaneous hydropower works (MHPW and the electric power generation capacity (micro (µ, small (S, large (L. The characterized hydroelectricity generation systems were statistically evaluated to determine the reduction in corresponding life cycle GHG emissions. A total of eight unique categorization codes (I-S, I-L, D-µ, D-S, D-L, PS-L, MHPW-µ, MHPW-S were designated to the 19 hydroelectricity generation LCA studies (representing 178 hydropower cases using the proposed categorization index. The mean life cycle GHG emissions resulting from the use of I-S (N = 24, I-L (N = 8, D-µ (N = 3, D-S (N = 133, D-L (N = 3, PS-L (N = 3, MHPW-µ (N = 3, and MHPW-S (N = 1 hydroelectricity generation systems are 21.05 gCO2e/kWh, 40.63 gCO2e/kWh, 47.82 gCO2e/kWh, 27.18 gCO2e/kWh, 3.45 gCO2e/kWh, 256.63 gCO2e/kWh, 19.73 gCO2e/kWh, and 2.78 gCO2e/kWh, respectively. D-L hydroelectricity generation systems produced the minimum life cycle GHGs (considering the hydroelectricity generation system categories with a representation of at least two cases.

  10. Environmental and thermodynamic evaluation of CO2 capture, transport and storage with and without enhanced resource recovery

    International Nuclear Information System (INIS)

    Iribarren, Diego; Petrakopoulou, Fontina; Dufour, Javier

    2013-01-01

    This study evaluates the environmental and thermodynamic performance of six coal-fired power plants with CO 2 capture and storage. The technologies examined are post-combustion capture using monoethanolamine, membrane separation, cryogenic fractionation and pressure swing adsorption, pre-combustion capture through coal gasification, and capture performing conventional oxy-fuel combustion. The incorporation of CO 2 capture is evaluated both on its own and in combination with CO 2 transport and geological storage, with and without beneficial use. Overall, we find that pre-combustion CO 2 capture and post-combustion through membrane separation present relatively low life-cycle environmental impacts and high exergetic efficiencies. When accounting for transport and storage, the environmental impacts increase and the efficiencies decrease. However, a better environmental performance can be achieved for CO 2 capture, transport and storage when incorporating beneficial use through enhanced oil recovery. The performance with enhanced coal-bed methane recovery, on the other hand, depends on the impact categories evaluated. The incorporation of methane recovery results in a better thermodynamic performance, when compared to the incorporation of oil recovery. The cumulative energy demand shows that the integration of enhanced resource recovery strategies is necessary to attain favourable life-cycle energy balances. - Highlights: ► Evaluation of six different CO 2 capture technologies for coal-fired power plants. ► Calculation of life-cycle environmental impacts and exergetic efficiencies. ► Suitability of post-combustion capture with membrane separation. ► Suitability of pre-combustion capture through coal gasification. ► Improved performance when incorporating enhanced resource recovery

  11. CO2 capture from power plants. Part I : A parametric study of the technical performance based on monoethanolamine

    NARCIS (Netherlands)

    Abu-Zahra, M. R. M.; Schneiders, L. H. J.; Niederer, J. P. M.; Feron, P. H. M.; Versteeg, G. F.

    Capture and storage of CO2 from fossil fuel fired power plants is drawing increasing interest as a potential method for the control of greenhouse gas emissions. An optimization and technical parameter study for a CO2 capture process from flue gas of a 600 MWe bituminous coal fired power plant, based

  12. CO2 capture from power plants: Part I. A parametric study of the technical performance based on monoethanolamine

    NARCIS (Netherlands)

    Abu-Zahra, Mohammad R.M.; Schneiders, Léon H.J.; Niederer, John; Feron, Paul H.M.; Versteeg, Geert

    2007-01-01

    Capture and storage of CO2 from fossil fuel fired power plants is drawing increasing interest as a potential method for the control of greenhouse gas emissions. An optimization and technical parameter study for a CO2 capture process from flue gas of a 600 MWe bituminous coal fired power plant, based

  13. JOINT ECONOMIC AND ENVIRONMENTAL OPTIMIZATION OF HYBRID POWER SUPPLY FOR LARGE SCALE RO-DESALINATION PLANT: WITH AND WITHOUT CO2 SEQUESTRATION

    Directory of Open Access Journals (Sweden)

    EMAN A. TORA

    2016-07-01

    Full Text Available In this paper, a multi- objective optimization approach is introduced to define a hybrid power supply system for a large scale RO- desalination plant. The target is to integrate a number of locally available energy resources to generate the electricity demand of the RO- desalination plant with minimizing both the electricity generation cost and the greenhouse gas emissions whereby carbon dioxide sequestration may be an option. The considered energy resources and technologies are wind turbines, solar PV, combined cycles with natural gas turbines, combined cycles with coal gasification, pulverized coal with flue gas desulfurization, and biomass combined heat and power CHP. These variable energy resources are investigated under different constraints on the renewable energy contribution. Likewise, the effect of carbon dioxide sequestration is included. Accordingly, five scenarios have been analyzed. Trade- offs between the minimum electricity generation cost and the minimum greenhouse gas emissions have been determined and represented in Pareto curves using the constraint method (. The results highlight that among the studied fossil fuel technologies, the integrated combined cycle natural gas turbines can provide considerable fraction of the needed power supply. Likewise, wind turbines are the most effective technology among renewable energy options. When CO2 sequestration applied, the costs increase and significant changes in the optimum combination of renewable energy resources have been monitored. In that case, solar PV starts to appreciably compete. The optimum mix of energy resources extends to include biomass CHP as well.

  14. C.N. Cofrentes power up-rate up to 110 %. A challenge for cycle 14 core design

    International Nuclear Information System (INIS)

    Gomez Bernal, M.I.; Lopez Carbonell, M.T.; Garcia Delgado, L.

    2001-01-01

    C.N.Cofrentes is a GE design BWR reactor with 624 bundles in the core, a rated power of 2894 MWt and it is currently operating Cycle 13 at 104.2 % power. Commercial operation started in 1984 with 12-month cycles at rated power. Both cycle length and thermal power have been increased since then. Power has been up-rated in two steps, first at 102 % in Cycle 4 and later in Cycle 11 at 104.2%. Cycle length has been extended from the original 12-month to the currently 18-month cycles. Next cycle, Cycle 14, will be an 18-month cycle operating at 110 % power. This goal is a challenge for the in-house nuclear design team. Start up for Cycle 14 is planned for the first quarter of 2002. (author)

  15. Rational Construction of Hollow Core-Branch CoSe2 Nanoarrays for High-Performance Asymmetric Supercapacitor and Efficient Oxygen Evolution.

    Science.gov (United States)

    Chen, Tian; Li, Songzhan; Wen, Jian; Gui, Pengbin; Guo, Yaxiong; Guan, Cao; Liu, Jinping; Fang, Guojia

    2018-02-01

    Metal selenides have great potential for electrochemical energy storage, but are relatively scarce investigated. Herein, a novel hollow core-branch CoSe 2 nanoarray on carbon cloth is designed by a facile selenization reaction of predesigned CoO nanocones. And the electrochemical reaction mechanism of CoSe 2 in supercapacitor is studied in detail for the first time. Compared with CoO, the hollow core-branch CoSe 2 has both larger specific surface area and higher electrical conductivity. When tested as a supercapacitor positive electrode, the CoSe 2 delivers a high specific capacitance of 759.5 F g -1 at 1 mA cm -2 , which is much larger than that of CoO nanocones (319.5 F g -1 ). In addition, the CoSe 2 electrode exhibits excellent cycling stability in that a capacitance retention of 94.5% can be maintained after 5000 charge-discharge cycles at 5 mA cm -2 . An asymmetric supercapacitor using the CoSe 2 as cathode and an N-doped carbon nanowall as anode is further assembled, which show a high energy density of 32.2 Wh kg -1 at a power density of 1914.7 W kg -1 , and maintains 24.9 Wh kg -1 when power density increased to 7354.8 W kg -1 . Moreover, the CoSe 2 electrode also exhibits better oxygen evolution reaction activity than that of CoO. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Opportunities for Decarbonizing Existing U.S. Coal-Fired Power Plants via CO2 Capture, Utilization and Storage.

    Science.gov (United States)

    Zhai, Haibo; Ou, Yang; Rubin, Edward S

    2015-07-07

    This study employs a power plant modeling tool to explore the feasibility of reducing unit-level emission rates of CO2 by 30% by retrofitting carbon capture, utilization, and storage (CCUS) to existing U.S. coal-fired electric generating units (EGUs). Our goal is to identify feasible EGUs and their key attributes. The results indicate that for about 60 gigawatts of the existing coal-fired capacity, the implementation of partial CO2 capture appears feasible, though its cost is highly dependent on the unit characteristics and fuel prices. Auxiliary gas-fired boilers can be employed to power a carbon capture process without significant increases in the cost of electricity generation. A complementary CO2 emission trading program can provide additional economic incentives for the deployment of CCS with 90% CO2 capture. Selling and utilizing the captured CO2 product for enhanced oil recovery can further accelerate CCUS deployment and also help reinforce a CO2 emission trading market. These efforts would allow existing coal-fired EGUs to continue to provide a significant share of the U.S. electricity demand.

  17. Enhanced rate capability and cycling stability of core/shell structured CoFe{sub 2}O{sub 4}/onion-like C nanocapsules for lithium-ion battery anodes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xianguo, E-mail: liuxianguohugh@gmail.com [School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243002 (China); Wu, Niandu; Cui, Caiyun; Zhou, Pingping [School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243002 (China); Sun, Yuping [Center for Engineering Practice and Innovation Education, Anhui University of Technology, Maanshan 243032 (China)

    2015-09-25

    Highlights: • Core/shell-structured CoFe{sub 2}O{sub 4}/onion-like carbon nanocapsules have been prepared. • CoFe{sub 2}O{sub 4}/C nanocapsules possess good reversibility even when the current density is up to 4C. • CoFe{sub 2}O{sub 4}/C nanocapsules obtain a discharge capacity of 914.2 mA h g{sup −1} after 500 cycles at 0.1C. - Abstract: In this work, core/shell structured CoFe{sub 2}O{sub 4}/onion-like C nanocapsules have been successfully fabricated by the arc discharge method and air-annealing process and confirmed by X-ray diffraction and high-resolution transmission electron microscopy. The core/shell structure effectively withstands the volume change of CoFe{sub 2}O{sub 4} nanoparticles during the cycling process. Moreover, the onion-like C shells reduce the charge transfer resistance and facilitate electron and ion transport throughout the electrode. As a result, CoFe{sub 2}O{sub 4}/onion-like C nanocapsules exhibit excellent performance as a potential anode material for lithium ion batteries and deliver a reversible capacity of 914.2 mA h g{sup −1} at 0.1C, even after 500 cycles and recover its original capacity when the rate returns from 4C to the initial 0.1C after 120 cycles.

  18. Electrofishing power requirements in relation to duty cycle

    Science.gov (United States)

    Miranda, L.E.; Dolan, C.R.

    2004-01-01

    Under controlled laboratory conditions we measured the electrical peak power required to immobilize (i.e., narcotize or tetanize) fish of various species and sizes with duty cycles (i.e., percentage of time a field is energized) ranging from 1.5% to 100%. Electrofishing effectiveness was closely associated with duty cycle. Duty cycles of 10-50% required the least peak power to immobilize fish; peak power requirements increased gradually above 50% duty cycle and sharply below 10%. Small duty cycles can increase field strength by making possible higher instantaneous peak voltages that allow the threshold power needed to immobilize fish to radiate farther away from the electrodes. Therefore, operating within the 10-50% range of duty cycles would allow a larger radius of immobilization action than operating with higher duty cycles. This 10-50% range of duty cycles also coincided with some of the highest margins of difference between the electrical power required to narcotize and that required to tetanize fish. This observation is worthy of note because proper use of duty cycle could help reduce the mortality associated with tetany documented by some authors. Although electrofishing with intermediate duty cycles can potentially increase effectiveness of electrofishing, our results suggest that immobilization response is not fully accounted for by duty cycle because of a potential interaction between pulse frequency and duration that requires further investigation.

  19. Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part A

    DEFF Research Database (Denmark)

    Meroni, Andrea; La Seta, Angelo; Andreasen, Jesper Graa

    2016-01-01

    Axial-flow turbines represent a well-established technology for a wide variety of power generation systems. Compactness, flexibility, reliability and high efficiency have been key factors for the extensive use of axial turbines in conventional power plants and, in the last decades, in organic...... Rankine cycle power systems. In this two-part paper, an overall cycle model and a model of an axial turbine were combined in order to provide a comprehensive preliminary design of the organic Rankine cycle unit, taking into account both cycle and turbine optimal designs. Part A presents the preliminary...

  20. Feasibility and desirability of employing the thorium fuel cycle for power generation - 254

    International Nuclear Information System (INIS)

    Sehgal, B.R.

    2010-01-01

    Thorium fuel cycle for nuclear power generation has been considered since the very start of the nuclear power era. In spite of a very large amount of research, experimentation, pilot scale and prototypic scale installations, the thorium fuel was not adopted for large scale power generation [1,2]. This paper reviews the developments over the years on the front and the back-end of the thorium fuel cycle and describes the pros and cons of employing the thorium fuel cycle for large generation of nuclear power. It examines the feasibility and desirability of employing the thorium fuel cycle in concert with the uranium fuel cycle for power generation. (authors)

  1. Splitting CO2 with a ceria‐based redox cycle in a solar‐driven thermogravimetric analyzer

    Science.gov (United States)

    Takacs, M.; Ackermann, S.; Bonk, A.; Neises‐von Puttkamer, M.; Haueter, Ph.; Scheffe, J. R.; Vogt, U. F.

    2016-01-01

    Thermochemical splitting of CO2 via a ceria‐based redox cycle was performed in a solar‐driven thermogravimetric analyzer. Overall reaction rates, including heat and mass transport, were determined under concentrated irradiation mimicking realistic operation of solar reactors. Reticulated porous ceramic (RPC) structures and fibers made of undoped and Zr4+‐doped CeO2, were endothermally reduced under radiative fluxes of 1280 suns in the temperature range 1200–1950 K and subsequently re‐oxidized with CO2 at 950–1400 K. Rapid and uniform heating was observed for 8 ppi ceria RPC with mm‐sized porosity due to its low optical thickness and volumetric radiative absorption, while ceria fibers with μm‐sized porosity performed poorly due to its opacity to incident irradiation. The 10 ppi RPC exhibited higher fuel yield because of its higher sample density. Zr4+‐doped ceria showed increasing reduction extents with dopant concentration but decreasing specific CO yield due to unfavorable oxidation thermodynamics and slower kinetics. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1263–1271, 2017 PMID:28405030

  2. Splitting CO2 with a ceria-based redox cycle in a solar-driven thermogravimetric analyzer.

    Science.gov (United States)

    Takacs, M; Ackermann, S; Bonk, A; Neises-von Puttkamer, M; Haueter, Ph; Scheffe, J R; Vogt, U F; Steinfeld, A

    2017-04-01

    Thermochemical splitting of CO 2 via a ceria-based redox cycle was performed in a solar-driven thermogravimetric analyzer. Overall reaction rates, including heat and mass transport, were determined under concentrated irradiation mimicking realistic operation of solar reactors. Reticulated porous ceramic (RPC) structures and fibers made of undoped and Zr 4+ -doped CeO 2 , were endothermally reduced under radiative fluxes of 1280 suns in the temperature range 1200-1950 K and subsequently re-oxidized with CO 2 at 950-1400 K. Rapid and uniform heating was observed for 8 ppi ceria RPC with mm-sized porosity due to its low optical thickness and volumetric radiative absorption, while ceria fibers with μm-sized porosity performed poorly due to its opacity to incident irradiation. The 10 ppi RPC exhibited higher fuel yield because of its higher sample density. Zr 4+ -doped ceria showed increasing reduction extents with dopant concentration but decreasing specific CO yield due to unfavorable oxidation thermodynamics and slower kinetics. © 2016 American Institute of Chemical Engineers , 63: 1263-1271, 2017.

  3. More Energy-Efficient CO2 Capture from IGCC GE Flue Gases

    Directory of Open Access Journals (Sweden)

    Rakpong Peampermpool

    2017-03-01

    Full Text Available Carbon dioxide (CO2 emissions are one of the main reasons for the increase in greenhouse gasses in the earth’s atmosphere and carbon capture and sequestration (CCS is known as an effective method to reduce CO2 emissions on a larger scale, such as for fossil energy utilization systems. In this paper, the feasibility of capturing CO2 using cryogenic liquefaction and improving the capture rate by expansion will be discussed. The main aim was to design an energy-saving scheme for an IGCC (integrated gasification combined cycle power plant with CO2 cryogenic liquefaction capture. The experimental results provided by the authors, using the feed gas specification of a 740 MW IGCC General Electric (GE combustion power plant, demonstrated that using an orifice for further expanding the vent gas after cryogenic capture from 57 bar to 24 bar gave an experimentally observed capture rate up to 65%. The energy-saving scheme can improve the overall CO2 capture rate, and hence save energy. The capture process has also been simulated using Aspen HYSYS simulation software to evaluate its energy penalty. The results show that a 92% overall capture rate can be achieved by using an orifice.

  4. Nuclear power newsletter Vol. 1, no. 2

    International Nuclear Information System (INIS)

    2004-12-01

    The newsletter provides information on: Nuclear Power Plant Operating Performance and Life Cycle Management; Improving Human Performance, Quality and Technical Infrastructure Co-ordination of International Collaboration for the Development of Innovative Nuclear Technology; Technology Developments and Applications for Advanced Reactors

  5. Validity And Reliability Of The Stages Cycling Power Meter.

    Science.gov (United States)

    Granier, Cyril; Hausswirth, Christophe; Dorel, Sylvain; Yann, Le Meur

    2017-09-06

    This study aimed to determine the validity and the reliability of the Stages power meter crank system (Boulder, United States) during several laboratory cycling tasks. Eleven trained participants completed laboratory cycling trials on an indoor cycle fitted with SRM Professional and Stages systems. The trials consisted of an incremental test at 100W, 200W, 300W, 400W and four 7s sprints. The level of pedaling asymmetry was determined for each cycling intensity during a similar protocol completed on a Lode Excalibur Sport ergometer. The reliability of Stages and SRM power meters was compared by repeating the incremental test during a test-retest protocol on a Cyclus 2 ergometer. Over power ranges of 100-1250W the Stages system produced trivial to small differences compared to the SRM (standardized typical error values of 0.06, 0.24 and 0.08 for the incremental, sprint and combined trials, respectively). A large correlation was reported between the difference in power output (PO) between the two systems and the level of pedaling asymmetry (r=0.58, p system according to the level of pedaling asymmetry provided only marginal improvements in PO measures. The reliability of the Stages power meter at the sub-maximal intensities was similar to the SRM Professional model (coefficient of variation: 2.1 and 1.3% for Stages and SRM, respectively). The Stages system is a suitable device for PO measurements, except when a typical error of measurement power ranges of 100-1250W is expected.

  6. Method of preparation of a CO.sub.2 removal sorbent with high chemical stability during multiple cycles

    Science.gov (United States)

    Siriwardane, Ranjani V.; Rosencwaig, Shira

    2015-07-14

    Method for the production of a clay-alkali-amine CO.sub.2 sorbent prepared by integrating a clay substrate, basic alkali salt, and amine liquid. The basic alkali salt is present relative to the clay substrate in a weight ratio of from about 1 part to about 50 parts per 100 parts of the clay substrate. The amine liquid is present relative to a clay-alkali combination in a weight ratio of from about 1 part to about 10 parts per 10 parts of the clay-alkali combination. The clay substrate and basic alkali salt may be combined in a solid-solid heterogeneous mixture and followed by introduction of the amine liquid. Alternatively, an alkaline solution may be blended with the amine solution prior to contacting the clay substrate. The clay-alkali-amine CO.sub.2 sorbent is particularly advantageous for low temperature CO.sub.2 removal cycles in a gas stream having a CO.sub.2 concentration less than around 2000 ppm and an oxygen concentration around 21%, such as air. Results are presented illustrating the performance of the clay-alkali-amine CO.sub.2 sorbent compared to a clay-amine sorbent lacking the alkali inclusion.

  7. Detection Test for Leakage of CO2 into Sodium Loop

    International Nuclear Information System (INIS)

    Park, Sun Hee; Wi, Myung-Hwan; Min, Jae Hong

    2015-01-01

    This report is about the facility for the detection test for leakage of CO 2 into sodium loop. The facility for the detection test for leakage of CO 2 into sodium loop was introduced. The test will be carried out. Our experimental results are going to be expected to be used for approach methods to detect CO 2 leaking into sodium in heat exchangers. A sodium-and-carbon dioxide (Na-CO 2 ) heat exchanger is one of the key components for the supercritical CO 2 Brayton cycle power conversion system of sodium-cooled fast reactors (SFRs). A printed circuit heat exchanger (PCHE) is considered for the Na-CO 2 heat exchanger, which is known to have potential for reducing the volume occupied by the exchangers compared to traditional shell-and-tube heat exchangers. Among various issues about the Na- CO 2 exchanger, detection of CO 2 leaking into sodium in the heat exchanger is most important thing for its safe operation. It is known that reaction products from sodium and CO 2 such as sodium carbonate (Na 2 CO 3 ) and amorphous carbon are hardly soluble in sodium, which cause plug sodium channels. Detection technique for Na 2 CO 3 in sodium loop has not been developed yet. Therefore, detection of CO 2 and CO from reaction of sodium and CO 2 are proper to detect CO 2 leakage into sodium loop

  8. Theoretical And Experimental Investigations On The Plasma Of A CO2 High Power Laser

    Science.gov (United States)

    Abel, W.; Wallter, B.

    1984-03-01

    The CO2 high power laser is increasingly used in material processing. This application of the laser has to meet some requirements: at one hand the laser is a tool free of wastage, but at the other hand is to guarantee that the properties of that tool are constant in time. Therefore power, geometry and mode of the beam have to be stable over long intervalls, even if the laser is used in rough industrial environment. Otherwise laser material processing would not be competitive. The beam quality is affected by all components of the laser - by the CO2 plasma and its IR - amplification, by the resonator which at last generates the beam by optical feedback, and also by the electric power supply whose effects on the plasma may be measured at the laser beam. A transversal flow laser has been developed at the Technical University of Vienna in cooperation with VOest-Alpine AG, Linz (Austria). This laser produces 1 kW of beam power with unfolded resonator. It was subject to investigations presented in this paper.

  9. Cofiring versus biomass-fired power plants: GHG (Greenhouse Gases) emissions savings comparison by means of LCA (Life Cycle Assessment) methodology

    International Nuclear Information System (INIS)

    Sebastian, F.; Royo, J.; Gomez, M.

    2011-01-01

    One way of producing nearly CO 2 free electricity is by using biomass as a combustible. In many cases, removal of CO 2 in biomass grown is almost the same as the emissions for the bioelectricity production at the power plant. For this reason, bioelectricity is generally considered CO 2 neutral. For large-scale biomass electricity generation two alternatives can be considered: biomass-only fired power plants, or cofiring in an existing coal power plant. Among other factors, two important aspects should be analyzed in order to choose between the two options. Firstly, which is the most appealing alternative if their Greenhouse Gases (GHG) Emissions savings are taken into account. Secondly, which biomass resource is the best, if the highest impact reduction is sought. In order to quantify all the GHG emissions related to each system, a Life Cycle Assessment (LCA) methodology has been performed and all the processes involved in each alternative have been assessed in a cradle-to-grave manner. Sensitivity analyses of the most dominant parameters affecting GHG emissions, and comparisons between the obtained results, have also been carried out.

  10. An oxyfuel-power-plant as an example of object oriented modelling and predictive control of the fuel gas cycle; Objektorientierte Modellierung und praediktive Regelung des Rauchgaskreislaufs eines Oxyfuel-Kraftwerksprozesses

    Energy Technology Data Exchange (ETDEWEB)

    Noetges, Thomas

    2008-07-01

    For a reduction of CO2 emissions, research is made on new fossil power plant concepts with integrated CO2 separation. This includes a new oxyfuel power plant process developed in the context of the OXYCOAL-AC project of RWTH Aachen University. The central component of this process is a ceramic membrane which at high temperatures and pressure ratios enriches recirculated flue gas with oxygen from ambient air and uses this mixture for combustion of coal. The process promises economically efficient separation of the CO2 produced. The author describes the modelling, simulation and control of the flue gas cycle of the process. The simulations enable the investigation of a process which is not yet put into practice completely. Further, a control concept for the flue gas cycle is proposed, and first results are presented. (orig.)

  11. Use of real options in nuclear power plant valuation in the presence of uncertainty with CO2 emission credit

    International Nuclear Information System (INIS)

    Kiriyama, Eriko; Suzuki, Atsuyuki

    2004-01-01

    The purpose of this study is to analyze the value of an investment in power generation assets that do not emit CO 2 , by using a real option model. This study evaluates the effects of future uncertainty on investment decision-making, by focusing on the uncertainty of CO 2 emission credits [yen/t-CO 2 ] in the fairly near future in Japan. Electric utilities are required to keep plans to prepare for various future uncertainties such as the price of CO 2 emission credits. The real option approach can evaluate the option value of decision-making under uncertainty. This study examined the option value of a power plant [yen/KW] to evaluate the effects of an externality under uncertainty. The results showed that nuclear power would have the most value under the forthcoming CO 2 emission limitations. In order to secure the effectiveness of measures against global warming, we should reconsider the roles of nuclear power plants in Japan. Finally, the real option model is shown to be an effective candidate for a decision-making support tool to deal with problems in energy environmental policy. (author)

  12. POWER CYCLE AND STRESS ANALYSES FOR HIGH TEMPERATURE GAS-COOLED REACTOR

    International Nuclear Information System (INIS)

    Oh, Chang H; Davis, Cliff; Hawkes, Brian D; Sherman, Steven R

    2007-01-01

    The Department of Energy and the Idaho National Laboratory are developing a Next Generation Nuclear Plant (NGNP) to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is two fold (1) efficient low cost energy generation and (2) hydrogen production. Although a next generation plant could be developed as a single-purpose facility, early designs are expected to be dual-purpose. While hydrogen production and advanced energy cycles are still in its early stages of development, research towards coupling a high temperature reactor, electrical generation and hydrogen production is under way. Many aspects of the NGNP must be researched and developed in order to make recommendations on the final design of the plant. Parameters such as working conditions, cycle components, working fluids, and power conversion unit configurations must be understood. Three configurations of the power conversion unit were demonstrated in this study. A three-shaft design with three turbines and four compressors, a combined cycle with a Brayton top cycle and a Rankine bottoming cycle, and a reheated cycle with three stages of reheat were investigated. An intermediate heat transport loop for transporting process heat to a High Temperature Steam Electrolysis (HTSE) hydrogen production plant was used. Helium, CO2, and a 80% nitrogen, 20% helium mixture (by weight) were studied to determine the best working fluid in terms cycle efficiency and development cost. In each of these configurations the relative component size were estimated for the different working fluids. The relative size of the turbomachinery was measured by comparing the power input/output of the component. For heat exchangers the volume was computed and compared. Parametric studies away from the baseline values of the three-shaft and combined cycles were performed to determine the effect of varying conditions in the cycle. This gives some insight into the sensitivity of these cycles to

  13. Alternative ORC bottoming cycles FOR combined cycle power plants

    International Nuclear Information System (INIS)

    Chacartegui, R.; Sanchez, D.; Munoz, J.M.; Sanchez, T.

    2009-01-01

    In this work, low temperature Organic Rankine Cycles are studied as bottoming cycle in medium and large scale combined cycle power plants. The analysis aims to show the interest of using these alternative cycles with high efficiency heavy duty gas turbines, for example recuperative gas turbines with lower gas turbine exhaust temperatures than in conventional combined cycle gas turbines. The following organic fluids have been considered: R113, R245, isobutene, toluene, cyclohexane and isopentane. Competitive results have been obtained for toluene and cyclohexane ORC combined cycles, with reasonably high global efficiencies. The paper is structured in four main parts. A review of combined cycle and ORC cycle technologies is presented, followed by a thermodynamic analysis of combined cycles with commercial gas turbines and ORC low temperature bottoming cycles. Then, a parametric optimization of an ORC combined cycle plant is performed in order to achieve a better integration between these two technologies. Finally, some economic considerations related to the use of ORC in combined cycles are discussed.

  14. The right place for the right job in the photovoltaic life cycle.

    Science.gov (United States)

    Kawajiri, Kotaro; Genchi, Yutaka

    2012-07-03

    The potential for photovoltaic power generation (PV) to reduce primary energy consumption (PEC) and CO(2) emissions depends on the physical locations of each stage of its life cycle. When stages are optimally located, CO(2) emissions are reduced nearly ten times as much as when each stage is located in the country having the largest current market share. The usage stage contributes the most to reducing CO(2) emissions and PEC, and total CO(2) emissions actually increase when PV is installed in countries having small CO(2) emissions from electricity generation. Global maps of CO(2) reduction potential indicate that Botswana and Gobi in Mongolia are the optimal locations to install PV due to favorable conditions for PV power generation and high CO(2) emissions from current electricity generation. However, the small electricity demand in those countries limits the contribution to global CO(2) reduction. The type of PVs has a small but significant effect on life cycle PEC and CO(2) emissions.

  15. Porous NiCo2S4-halloysite hybrid self-assembled from nanosheets for high-performance asymmetric supercapacitor applications

    Science.gov (United States)

    Chai, Hui; Dong, Hong; Wang, Yucheng; Xu, Jiayu; Jia, Dianzeng

    2017-04-01

    The porous nanostructures have drawn considerable attention because of their abundant pore volume and unique properties that provide outstanding performance in catalysis and energy storage applications. This study proposes the growth mechanism of porous NiCo2S4 composited with halloysite (HL) via a self-assembly method using halloysite as a template and component. Electrochemical tests showed that the NiCo2S4-HL exhibited an ultrahigh specific capacitance (Csp) (589C g-1 at 1A g-1) and good cycle stability (Csp retention of 86% after 1000 cycles). The desirable capacitive performance of the NiCo2S4-HL can be attributed to the large specific surface area and short diffusion path for electrons and ions in the hierarchical porous structure. The superior electrochemical performances with the energy density of 35.48 W h kg-1 at a power density of 199.9 W kg-1 were achieved in an assembled aqueous asymmetric supercapacitor (ASC) device using NiCo2S4-HL as a positive electrode and N-doped graphene (NG) as a negative electrode. Moreover, the NiCo2S4-HL//NG asymmetric supercapacitor achieved outstanding cycle stability (also retained 83.2% after 1700 cycles). The high-performance of the ASC device will undoubtedly make the porous NiCo2S4-HL as potential electrode materials attractive in energy storage systems.

  16. Thermal Integration of CO{sub 2} Compression Processes with Coal-Fired Power Plants Equipped with Carbon Capture

    Energy Technology Data Exchange (ETDEWEB)

    Edward Levy

    2012-06-29

    Coal-fired power plants, equipped either with oxycombustion or post-combustion CO{sub 2} capture, will require a CO{sub 2} compression system to increase the pressure of the CO{sub 2} to the level needed for sequestration. Most analyses show that CO{sub 2} compression will have a significant effect on parasitic load, will be a major capital cost, and will contribute significantly to reduced unit efficiency. This project used first principle engineering analyses and computer simulations to determine the effects of utilizing compressor waste heat to improve power plant efficiency and increase net power output of coal-fired power plants with carbon capture. This was done for units with post combustion solvent-based CO{sub 2} capture systems and for oxyfired power plants, firing bituminous, PRB and lignite coals. The thermal integration opportunities analyzed for oxycombustion capture are use of compressor waste heat to reheat recirculated flue gas, preheat boiler feedwater and predry high-moisture coals prior to pulverizing the coal. Among the thermal integration opportunities analyzed for post combustion capture systems are use of compressor waste heat and heat recovered from the stripper condenser to regenerate post-combustion CO{sub 2} capture solvent, preheat boiler feedwater and predry high-moisture coals. The overall conclusion from the oxyfuel simulations is that thermal integration of compressor heat has the potential to improve net unit heat rate by up to 8.4 percent, but the actual magnitude of the improvement will depend on the type of heat sink used and to a lesser extent, compressor design and coal rank. The simulations of a unit with a MEA post combustion capture system showed that thermal integration of either compressor heat or stripper condenser heat to preheat boiler feedwater would result in heat rate improvements from 1.20 percent to 4.19 percent. The MEA capture simulations further showed that partial drying of low rank coals, done in combination

  17. A systematic approach to assessing measurement uncertainty for CO2 emissions from coal-fired power plants

    DEFF Research Database (Denmark)

    Wagner, Claas; Esbensen, Kim

    2011-01-01

    An augmented measurement uncertainty approach for CO2 emissions from coal-fired power plants with a focus on the often forgotten contributions from sampling errors occurring over the entire fuel-to-emission pathway is presented. Current methods for CO2 emission determination are evaluated in detail......, from which a general matrix scheme is developed that includes all factors and stages needed for total CO2 determination, which is applied to the monitoring plan of a representative medium-sized coal-fired power plant. In particular sampling involved significant potential errors, as identified...... of these three materials were also given full attention. A systematic error (bias) is present in the current sampling approach, which increases the present uncertainty estimate unnecessarily. For both primary sampling and analytical sample extraction steps, random variations, which hitherto only have been...

  18. Proton- and x-ray beams generated by ultra-fast CO2 lasers for medical applications

    Science.gov (United States)

    Pogorelsky, Igor; Polyanskiy, Mikhail; Yakimenko, Vitaly; Ben-Zvi, Ilan; Shkolnikov, Peter; Najmudin, Zulfikar; Palmer, Charlotte A. J.; Dover, Nicholas P.; Oliva, Piernicola; Carpinelli, Massimo

    2011-05-01

    Recent progress in using picosecond CO2 lasers for Thomson scattering and ion-acceleration experiments underlines their potentials for enabling secondary radiation- and particle- sources. These experiments capitalize on certain advantages of long-wavelength CO2 lasers, such as higher number of photons per energy unit, and favorable scaling of the electrons' ponderomotive energy and critical plasma density. The high-flux x-ray bursts produced by Thomson scattering of the CO2 laser off a counter-propagating electron beam enabled high-contrast, time-resolved imaging of biological objects in the picosecond time frame. In different experiments, the laser, focused on a hydrogen jet, generated monoenergetic proton beams via the radiation-pressure mechanism. The strong power-scaling of this regime promises realization of proton beams suitable for laser-driven proton cancer therapy after upgrading the CO2 laser to sub-PW peak power. This planned improvement includes optimizing the 10-μm ultra-short pulse generation, assuring higher amplification in the CO2 gas under combined isotopic- and power-broadening effects, and shortening the postamplification pulse to a few laser cycles (150-200 fs) via chirping and compression. These developments will move us closer to practical applications of ultra-fast CO2 lasers in medicine and other areas.

  19. A ten year perspective on power balances and CO2 emissions in Northern Europe

    International Nuclear Information System (INIS)

    Tennbakk, Berit; Torgersen, Lasse

    2003-10-01

    The electric power balance and electricity trade will change a lot in Northern Europe over the next decade. Independent of the price of emission quotas, the balance will worsen, especially for Sweden and Germany, but the absolute numbers are strongly dependent on the demand growth. New production capacity will be built primarily in the Netherlands and Norway. Finland will also have a growing need of imported power until the new nuclear power plant is running, around 2012. Denmark will remain a net exporter. If the construction of new generating capacity is slowed down by economic or administrative reasons, the raising prices will lead to higher production in the Nordic coal fired plants. The CO 2 emissions will increase and the Nordic countries will become net importers of emission quotas, even at a quota price of 20 Euros per ton CO 2 , since new natural gas plants in Norway and Netherlands will outperform existing coal plants in Poland and Germany at high quota prices

  20. CO2 Capture Rate Sensitivity Versus Purchase of CO2 Quotas. Optimizing Investment Choice for Electricity Sector

    Directory of Open Access Journals (Sweden)

    Coussy Paula

    2014-09-01

    Full Text Available Carbon capture technology (and associated storage, applied to power plants, reduces atmospheric CO2 emissions. This article demonstrates that, in the particular case of the deployment phase of CO2 capture technology during which CO2 quota price may be low, capturing less than 90% of total CO2 emissions from power plants can be economically attractive. Indeed, for an electric power company capture technology is interesting, only if the discounted marginal cost of capture is lower than the discounted marginal cost of purchased quotas. When CO2 price is low, it is interesting to have flexibility and reduce the overall capture rate of the site, by stopping the capture system of one of the combustion trains if the site has multiple ones, or by adopting less than 90% CO2 capture rate.

  1. CO2 laser-driven Stirling engine. [space power applications

    Science.gov (United States)

    Lee, G.; Perry, R. L.; Carney, B.

    1978-01-01

    A 100-W Beale free-piston Stirling engine was powered remotely by a CO2 laser for long periods of time. The engine ran on both continuous-wave and pulse laser input. The working fluid was helium doped with small quantities of sulfur hexafluoride, SF6. The CO2 radiation was absorbed by the vibrational modes of the sulfur hexafluoride, which in turn transferred the energy to the helium to drive the engine. Electrical energy was obtained from a linear alternator attached to the piston of the engine. Engine pressures, volumes, and temperatures were measured to determine engine performance. It was found that the pulse radiation mode was more efficient than the continuous-wave mode. An analysis of the engine heat consumption indicated that heat losses around the cylinder and the window used to transmit the beam into the engine accounted for nearly half the energy input. The overall efficiency, that is, electrical output to laser input, was approximately 0.75%. However, this experiment was not designed for high efficiency but only to demonstrate the concept of a laser-driven engine. Based on this experiment, the engine could be modified to achieve efficiencies of perhaps 25-30%.

  2. On-road assessment of light duty vehicles in Delhi city: Emission factors of CO, CO2 and NOX

    Science.gov (United States)

    Jaiprakash; Habib, Gazala

    2018-02-01

    This study presents the technology based emission factors of gaseous pollutants (CO, CO2, and NOX) measured during on-road operation of nine passenger cars of diesel, gasoline, and compressed natural gas (CNG). The emissions from two 3-wheelers, and three 2-wheelers were measured by putting the vehicles on jacks and operating them according to Modified Indian Driving Cycle (MIDC) at no load condition. The emission factors observed in the present work were significantly higher than values reported from dynamometer study by Automotive Research Association of India (ARAI). Low CO (0.34 ± 0.08 g km-1) and high NOX (1.0 ± 0.4 g km-1) emission factors were observed for diesel passenger cars, oppositely high CO (2.2 ± 2.6 g km-1) and low NOX (1.0 ± 1.6 g km-1) emission factors were seen for gasoline powered cars. The after-treatment technology in diesel vehicles was effective in CO reduction. While the use of turbocharger in diesel vehicles to generate high combustion temperature and pressure produces more NOx, probably which may not be effectively controlled by after-treatment device. The after-treatment devices in gasoline powered Post-2010, Post-2005 vehicles can be acclaimed for reduced CO emissions compared to Post-2000 vehicles. This work presents a limited data set of emission factors from on-road operations of light duty vehicles, this limitation can be improved by further measurements of emissions from similar vehicles.

  3. Analysis of thermal cycles and working fluids for power generation in space

    International Nuclear Information System (INIS)

    Tarlecki, Jason; Lior, Noam; Zhang Na

    2007-01-01

    Production of power in space for terrestrial use is of great interest in view of the rapidly rising power demand and its environmental impacts. Space also offers a very low temperature, making it a perfect heat sink for power plants, thus offering much higher efficiencies. This paper focuses on the evaluation and analysis of thermal Brayton, Ericsson and Rankine power cycles operating at space conditions on several appropriate working fluids. Under the examined conditions, the thermal efficiency of Brayton cycles reaches 63%, Ericsson 74%, and Rankine 85%. These efficiencies are significantly higher than those for the computed or real terrestrial cycles: by up to 45% for the Brayton, and 17% for the Ericsson; remarkably 44% for the Rankine cycle even when compared with the best terrestrial combined cycles. From the considered working fluids, the diatomic gases (N 2 and H 2 ) produce somewhat better efficiencies than the monatomic ones in the Brayton and Rankine cycles. The Rankine cycles require radiator areas that are larger by up to two orders of magnitude than those required for the Brayton and Ericsson cycles. The results of the analysis of the sensitivity of the cycle performance parameters to major parameters such as turbine inlet temperature and pressure ratio are presented, equations or examining the effects of fluid properties on the radiator area and pressure drop were developed, and the effects of the working fluid properties on cycle efficiency and on the power production per unit radiator area were explored to allow decisions on the optimal choice of working fluids

  4. CO2 separation by calcium looping from full and partial fuel oxidation processes

    International Nuclear Information System (INIS)

    Sivalingam, Senthoorselvan

    2013-01-01

    This thesis work deals with the research and development of calcium looping process for CO 2 separation from full and partial fuel oxidation based power generation systems. CO 2 is the main greenhouse gas and undoubtedly a major contributor to the global warming. It is estimated that more than one third of the total anthropogenic CO 2 emissions come from fossil fuel based heat and power generation. Moreover, fossil fuels are unlikely to be phased out rapidly, since developing alternative energy sources not only take time but also require huge investments and infrastructure. An alternative way to reduce emissions in a medium term is to capture the CO 2 from fossil fueled power plants and store it away from the atmosphere. This process system combining a bunch of technologies is called carbon capture and storage (CCS). CO 2 capture is an important and costly part of CCS and an array of technologies is considered for this. Calcium looping (CaL) is one of such and seems to offer effective and efficient CO 2 separation from fuel oxidation processes. CaL process involves separation of CO 2 at high temperatures (600-700 C) by calcium sorbents (CaO). CO 2 reacts with CaO in a carbonation process and produces CaCO 3 . In a subsequent thermal regeneration (>850 C) called calcination, the CO 2 is released from CaCO 3 . By alternating carbonations and calcinations over multiple cycles, CO 2 is separated from a gas stream. Moreover, the CaL is realised in industrial scale with dual fluidised bed reactors for CO 2 capture (the carbonator) and sorbent regeneration (the calciner). As a process in the development, research is still required in many aspects from thermodynamic modeling to experimental studies. Research works have been carried out in process simulations, sorbent reactivity and optimisation studies in a controlled reactor environment and process parametric studies in a semi-pilot scale CaL test facility. ASPEN Plus power plant simulations integrating the CaL based CO 2

  5. Co(OH)2/RGO/NiO sandwich-structured nanotube arrays with special surface and synergistic effects as high-performance positive electrodes for asymmetric supercapacitors.

    Science.gov (United States)

    Xu, Han; Zhang, Chi; Zhou, Wen; Li, Gao-Ren

    2015-10-28

    High power density, high energy density and excellent cycling stability are the main requirements for high-performance supercapacitors (SCs) that will be widely used for portable consumer electronics and hybrid electric vehicles. Here we investigate novel types of hybrid Co(OH)2/reduced graphene oxide (RGO)/NiO sandwich-structured nanotube arrays (SNTAs) as positive electrodes for asymmetric supercapacitors (ASCs). The synthesized Co(OH)2/RGO/NiO SNTAs exhibit a significantly improved specific capacity (∼1470 F g(-1) at 5 mV s(-1)) and excellent cycling stability with ∼98% Csp retention after 10 000 cycles because of the fast transport and short diffusion paths for electroactive species, the high utilization rate of electrode materials, and special synergistic effects among Co(OH)2, RGO, and NiO. The high-performance ASCs are assembled using Co(OH)2/RGO/NiO SNTAs as positive electrodes and active carbon (AC) as negative electrodes, and they exhibit a high energy density (115 Wh kg(-1)), a high power density (27.5 kW kg(-1)) and an excellent cycling stability (less 5% Csp loss after 10 000 cycles). This study shows an important breakthrough in the design and fabrication of multi-walled hybrid nanotube arrays as positive electrodes for ASCs.

  6. Reduction of impurity contamination in a working gas for closed-cycle MHD power generation

    International Nuclear Information System (INIS)

    Endo, N.; Yoshikawa, K.; Shioda, S.

    1989-01-01

    The reduction of impurity contamination in a working inert gas for closed-cycle MHD power generation is examined. A conceptual operation system of regenerative heat exchangers is proposed for minimizing the amount of combustion gas which mixes in the working inert gas. Experiments have shown that this mixing can be reduced significantly by evacuating and flushing the heat exchangers after being heated by combustion gas. Calculations have shown that, among the main molecular contaminants in the working inert gas, CO 2 , H 2 O and O 2 can be removed as compounds with the seed material, while N 2 and H 2 can be reduced by a partial purification of the circulating working inert gas. (author)

  7. Thermodynamic assessment of amine based CO2 capture technologies in power plants based on European Benchmarking Task Force methodology

    NARCIS (Netherlands)

    Sanchez Fernandez, E.; Goetheer, E.L.V.; Manzolini, G.; Macchi, E.; Rezvani, S.; Vlugt, T.J.H.

    2014-01-01

    Post combustion CO2 capture (PCC) with amine solvents is seen as one of the possible technologies which can be implemented in the near term to significantly reduce CO2 emissions from fossil fuel power plants. One of the major concerns for its implementation at large scale in power plants is the high

  8. A performance analysis for MHD power cycles operating at maximum power density

    International Nuclear Information System (INIS)

    Sahin, Bahri; Kodal, Ali; Yavuz, Hasbi

    1996-01-01

    An analysis of the thermal efficiency of a magnetohydrodynamic (MHD) power cycle at maximum power density for a constant velocity type MHD generator has been carried out. The irreversibilities at the compressor and the MHD generator are taken into account. The results obtained from power density analysis were compared with those of maximum power analysis. It is shown that by using the power density criteria the MHD cycle efficiency can be increased effectively. (author)

  9. Superior supercapacitors based on nitrogen and sulfur co-doped hierarchical porous carbon: Excellent rate capability and cycle stability

    Science.gov (United States)

    Zhang, Deyi; Han, Mei; Wang, Bing; Li, Yubing; Lei, Longyan; Wang, Kunjie; Wang, Yi; Zhang, Liang; Feng, Huixia

    2017-08-01

    Vastly improving the charge storage capability of supercapacitors without sacrificing their high power density and cycle performance would bring bright application prospect. Herein, we report a nitrogen and sulfur co-doped hierarchical porous carbon (NSHPC) with very superior capacitance performance fabricated by KOH activation of nitrogen and sulfur co-doped ordered mesoporous carbon (NSOMC). A high electrochemical double-layer (EDL) capacitance of 351 F g-1 was observed for the reported NSHPC electrodes, and the capacitance remains at 288 F g-1 even under a large current density of 20 A g-1. Besides the high specific capacitance and outstanding rate capability, symmetrical supercapacitor cell based on the NSHPC electrodes also exhibits an excellent cycling performance with 95.61% capacitance retention after 5000 times charge/discharge cycles. The large surface area caused by KOH activation (2056 m2 g-1) and high utilized surface area owing to the ideal micro/mesopores ratio (2.88), large micropores diameter (1.38 nm) and short opened micropores structure as well as the enhanced surface wettability induced by N and S heteroatoms doping and improved conductivity induced by KOH activation was found to be responsible for the very superior capacitance performance.

  10. Specification of life cycle assessment in nuclear power plants

    International Nuclear Information System (INIS)

    Abbaspour, M.; Kargari, N.; Mastouri, R.

    2008-01-01

    Life Cycle Assessment is an environmental management tool for assessing the environmental impacts of a product of a process. life cycle assessment involves the evaluation of environmental impacts through all stages of life cycle of a product or process. In other words life cycle assessment has a c radle to grave a pproach. Some results of life cycle assessment consist of pollution prevention, energy efficient system, material conservation, economic system and sustainable development. All power generation technologies affect the environment in one way or another. The main environmental impact does not always occur during operation of power plant. The life cycle assessment of nuclear power has entailed studying the entire fuel cycle from mine to deep repository, as well as the construction, operation and demolition of the power station. Nuclear power plays an important role in electricity production for several countries. even though the use of nuclear power remains controversial. But due to the shortage of fossil fuel energy resources many countries have started to try more alternation to their sources of energy production. A life cycle assessment could detect all environmental impacts of nuclear power from extracting resources, building facilities and transporting material through the final conversion to useful energy services

  11. Non-Destructive Analysis of Degradation Mechanisms in Cycle-Aged Graphite/LiCoO2 Batteries

    Directory of Open Access Journals (Sweden)

    Liqiang Zhang

    2014-09-01

    Full Text Available Non-destructive analysis of degradation mechanisms can be very beneficial for the prognostics and health management (PHM study of lithium-ion batteries. In this paper, a type of graphite/LiCoO2 battery was cycle aged at high ambient temperature, then 25 parameters of the multi-physics model were identified. Nine key parameters degraded with the cycle life, and they were treated as indicators of battery degradation. Accordingly, the degradation mechanism was discussed by using the multi-physics model and key parameters, and the reasons for capacity fade and the internal resistance increase were analyzed in detail. All evidence indicates that the formation reaction of the solid electrolyte interface (SEI film is the main cause of battery degradation at high ambient temperature.

  12. Land-use change effects on fluxes and isotopic composition of CO2 and CH4 in Panama, and possible insights into the atmospheric H2 cycle

    Science.gov (United States)

    Pendall, E.; Schwendenmann, L.; Potvin, C.

    2003-12-01

    Land-use changes in tropical regions are believed to release a quantity of C to the atmosphere which is similar in magnitude to the entire "missing" sink for anthropogenic CO2. Our research attempts to evaluate carbon cycling in three land-cover systems in central Panama: cow pasture, native tree plantation, and undisturbed moist forest. In this ongoing project, we are collecting samples of air from profiles in the stable, nocturnal boundary layer, which is dominated by ecosystem respiration. Samples are analyzed for CO2 and its isotopes, CH4 and its C isotopic composition, N2O, H2, CO, and SF6. We use a flux-gradient method to estimate ecosystem-scale fluxes of trace gases from soil to the atmosphere. Keeling plot intercepts reflect the respiratory contribution of C3 and C4 biomass under contrasting land cover systems, and how this varies with pronounced wet-dry seasonal cycles. C isotopes of methane and gradients of molecular hydrogen provide insight into the source of methane production from pasture and plantation soils. Rainforest soils, in contrast, are sinks for both atmospheric methane and hydrogen. The process oriented nature of this field experiment will contribute to parameterization of carbon cycle models at a variety of spatial scales.

  13. Optimized CO2-flue gas separation model for a coal fired power plant

    Energy Technology Data Exchange (ETDEWEB)

    Arachchige, Udara S.P.R. [Telemark University College, Porsgrunn (Norway); Mohsin, Muhammad [Telemark University College, Porsgrunn (Norway); Melaaen, Morten C. [Telemark University College, Porsgrunn (Norway); Tel-Tek, Porsgrunn (Norway)

    2013-07-01

    The detailed description of the CO2 removal process using mono-ethylamine (MEA) as a solvent for coal-fired power plant is present in this paper. The rate based Electrolyte NRTL activity coefficient model was used in the Aspen Plus. The complete removal process with re-circulating solvent back to the absorber was implemented with the sequential modular method in Aspen Plus. The most significant cost related to CO2 capture is the energy requirement for re-generating solvent, i.e. re-boiler duty. Parameters’ effects on re-boiler duty were studied, resulting decreased re-boiler duty with the packing height and absorber packing diameter, absorber pressure, solvent temperature, stripper packing height and diameter. On the other hand, with the flue gas temperature, re-boiler duty is increased. The temperature profiles and CO2 loading profiles were used to check the model behavior.

  14. Carbon dioxide based power generation in renewable energy systems

    International Nuclear Information System (INIS)

    Kumar, Pramod; Srinivasan, Kandadai

    2016-01-01

    After a substantial impact on refrigeration, carbon dioxide (CO_2) is gaining considerable attention as a working fluid for thermal power generation. This can be attributed mainly to its excellent heat transfer properties and compactness of components arising from its high density. It has the merit of being amenable to operation in sub-, trans- or super-critical Brayton cycle modes. However, inhibiting factors are high pressures needed when operated in trans- or supercritical cycles and the work of compression eroding most of the work of expansion in sub-critical cycle operation. Some of the lacunae of CO_2 such as high work of compression can be alleviated by using non-mechanical means such as thermal compression using the adsorption technique either for partial compression in high pressure Brayton cycles or for total compression in low pressure cycles. CO_2 has also been proposed as an additive to flammable hydrocarbons such that their flammability can be suppressed and yet retaining their other desirable thermodynamic qualities. This review explores the potential and limitations of thermodynamic cycles where either CO_2 is used alone or as a component in mixture of working fluids. Inter alia, it also highlights the issues of regulation of load management using the efficiency-specific power output plane. When used as a blending component, pinch point in the regenerators affects the cycle performance. The objective is to identify research and developmental challenges involving CO_2 as a working fluid specifically for solar power generation.

  15. Hollow fiber membrane contactors for CO2 capture: modeling and up-scaling to CO2 capture for an 800 MWe coal power station

    NARCIS (Netherlands)

    Kimball, E.; Al-Azki, A.; Gomez, A.; Goetheer, E.L.V.; Booth, N.; Adams, D.; Ferre, D.

    2014-01-01

    A techno-economic analysis was completed to compare the use of Hollow Fiber Membrane Modules (HFMM) with the more conventional structured packing columns as the absorber in amine-based CO2capture systems for power plants. In order to simulate the operation of industrial scale HFMMsystems, a

  16. Solar Thermochemical Energy Storage Through Carbonation Cycles of SrCO3/SrO Supported on SrZrO3.

    Science.gov (United States)

    Rhodes, Nathan R; Barde, Amey; Randhir, Kelvin; Li, Like; Hahn, David W; Mei, Renwei; Klausner, James F; AuYeung, Nick

    2015-11-01

    Solar thermochemical energy storage has enormous potential for enabling cost-effective concentrated solar power (CSP). A thermochemical storage system based on a SrO/SrCO3 carbonation cycle offers the ability to store and release high temperature (≈1200 °C) heat. The energy density of SrCO3/SrO systems supported by zirconia-based sintering inhibitors was investigated for 15 cycles of exothermic carbonation at 1150 °C followed by decomposition at 1235 °C. A sample with 40 wt % of SrO supported by yttria-stabilized zirconia (YSZ) shows good energy storage stability at 1450 MJ m(-3) over fifteen cycles at the same cycling temperatures. After further testing over 45 cycles, a decrease in energy storage capacity to 1260 MJ m(-3) is observed during the final cycle. The decrease is due to slowing carbonation kinetics, and the original value of energy density may be obtained by lengthening the carbonation steps. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Finite time thermodynamics of power and refrigeration cycles

    CERN Document Server

    Kaushik, Shubhash C; Kumar, Pramod

    2017-01-01

    This book addresses the concept and applications of Finite Time Thermodynamics to various thermal energy conversion systems including heat engines, heat pumps, and refrigeration and air-conditioning systems. The book is the first of its kind, presenting detailed analytical formulations for the design and optimisation of various power producing and cooling cycles including but not limited to: • Vapour power cycles • Gas power cycles • Vapour compression cycles • Vapour absorption cycles • Rankine cycle coupled refrigeration systems Further, the book addresses the thermoeconomic analysis for the optimisation of thermal cycles, an important field of study in the present age and which is characterised by multi-objective optimization regarding energy, ecology, the environment and economics. Lastly, the book provides the readers with key techniques associated with Finite Time Thermodynamics, allowing them to understand the relevance of irreversibilitie s associated with real processes and the scientific r...

  18. Hydrogenated CoOx nanowire@Ni(OH)2 nanosheet core-shell nanostructures for high-performance asymmetric supercapacitors

    Science.gov (United States)

    Zhu, Jianxiao; Huang, Lei; Xiao, Yuxiu; Shen, Leo; Chen, Qi; Shi, Wangzhou

    2014-05-01

    We report a facile strategy to prepare 3D core-shell nanowire heterostructures with microporous hydrogenated CoOx (H-CoOx) nanowires as the conducting scaffold to support Ni(OH)2 nanosheets. Benefiting from the H-CoOx nanowire core to provide the effective pathway for charge transport and the core-shell heterostructures with synergistic effects, the H-CoOx@Ni(OH)2 core-shell nanowire electrode achieved the specific capacitance of 2196 F g-1 (areal capacitance of 5.73 F cm-2), which is approximately a 1.4-fold enhancement compared with the Co3O4@Ni(OH)2 core-shell nanowires. An aqueous asymmetric supercapacitor (ASC) device was fabricated by using H-CoOx@Ni(OH)2 nanowires as the positive electrode and reduced graphene oxide @Fe3O4 nanocomposites as the negative electrode. The ASCs achieved high energy density (~45.3 W h kg-1 at 1010 W kg-1), high power density (~7080 W kg-1 at 23.4 W h kg-1) and high cycling stability. Furthermore, after charging for ~1 min, one such 22 cm2 ASC device demonstrated to be able to drive a small windmill (0.8 V, 0.1 W) for 20 min. Two such ASCs connected in series can power up a seven-color LED (3.2 V) efficiently.We report a facile strategy to prepare 3D core-shell nanowire heterostructures with microporous hydrogenated CoOx (H-CoOx) nanowires as the conducting scaffold to support Ni(OH)2 nanosheets. Benefiting from the H-CoOx nanowire core to provide the effective pathway for charge transport and the core-shell heterostructures with synergistic effects, the H-CoOx@Ni(OH)2 core-shell nanowire electrode achieved the specific capacitance of 2196 F g-1 (areal capacitance of 5.73 F cm-2), which is approximately a 1.4-fold enhancement compared with the Co3O4@Ni(OH)2 core-shell nanowires. An aqueous asymmetric supercapacitor (ASC) device was fabricated by using H-CoOx@Ni(OH)2 nanowires as the positive electrode and reduced graphene oxide @Fe3O4 nanocomposites as the negative electrode. The ASCs achieved high energy density (~45.3 W h kg-1 at

  19. One-step hydrothermal synthesis of sandwich-type NiCo2S4@reduced graphene oxide composite as active electrode material for supercapacitors

    Science.gov (United States)

    Wang, Fangping; Li, Guifang; Zhou, Qianqian; Zheng, Jinfeng; Yang, Caixia; Wang, Qizhao

    2017-12-01

    A facile one step hydrothermal process is developed for the synthesis of NiCo2S4@reduced graphene oxide (NiCo2S4@RGO) composite as electrode for electrochemical supercapacitors. This NiCo2S4@RGO electrode exhibits an ultrahigh specific capacitance of 2003 F g-1 at 1 A g-1 and 1726 F g-1 at 20 A g-1 (86.0% capacitance retention from 1 A g-1 to 20 A g-1), excellent cycling stabilities (86.0% retention after 3500 cycles). Moreover, an asymmetric supercapacitor is successfully assembled by using NiCo2S4@RGO nanoparticle as the positive electrode and active carbon(AC) as the negative electrode in 2 M KOH electrolyte. The fabricated NiCo2S4@RGO//AC asymmetric supercapacitor exhibits a high energy density of 21.9 Wh kg-1 at a power density of 417.1 W kg-1 and still remains an impressive energy density of 13.5 Wh kg-1 at a large power density of 2700 W kg-1. The results demonstrate that the NiCo2S4@RGO composite is a promising electrode material as supercapacitors in energy storage.

  20. Measurements and modeling of CO2 concentration and isotopes to improve process-level understanding of Arctic and boreal carbon cycling. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Keeling, Ralph F. [Univ. of California, San Diego, CA (United States). Scripps Inst. of Oceanography

    2017-09-29

    The major goal of this project was to improve understanding of processes that control the exchanges of CO2 between the atmosphere and the land biosphere on decadal and longer time scales. The approach involves measuring the changes in atmospheric CO2 concentration and the isotopes of CO2 (13C/12C and 18O/16O) at background stations and uses these and other datasets to challenge and improve numerical models of the earth system. The project particularly emphasized the use of these data to improve understanding of changes occurring in boreal and arctic ecosystems over the past 50 years and to seek from these data improved understanding of large-scale processes impacting carbon cycling, such as the responses to warming, CO2 fertilization, and disturbance. The project also led to advances in the understanding of changes in water-use efficiency of land ecosystems globally based on trends in 13C/12C. The core element of this project was providing partial support for continuing measurements of CO2 concentrations and isotopes from the Scripps CO2 program, initiated by C. D. Keeling in the 1960s. The measurements included analysis of flasks collected at an array of ten stations distributed from the Arctic to the Antarctic. The project also supported modeling studies and interpretive work to help understand the origins of the large ~50% increase in the amplitude of the atmospheric CO2 cycle detected at high northern latitudes between 1960 and present and to understand the long-term trend in carbon 13C/12C of CO2. The seasonal cycle work was advanced through collaborations with colleagues at MPI Jena and Imperial College

  1. Advanced Oxyfuel power plant process with CO{sub 2} separation for power generation from brown coal and competitionable for future; Innovativer Oxyfuel-Kraftwerksprozess mit CO{sub 2}-Abscheidung fuer eine auch in Zukunft wettbewerbsfaehige Stromerzeugung aus Braunkohle

    Energy Technology Data Exchange (ETDEWEB)

    Gilli, P.G.; Hellfritsch, S. [Technische Universitaet Dresden (Germany); Jentsch, N. [Vattenfall Europe Generation, Cottbus (Germany)

    2004-07-01

    The Oxyfuel process for lignite combustion with CO{sub 2} separation is illustrated by the example of a industrial-scale power plant process. Consequent optimisation of the process with integrated waste air utilisation and further efficiency-increasing measures will make the power plant as efficient as modern conventional lignite-fuelled power stations. (orig.)

  2. Reducing life cycle greenhouse gas emissions of corn ethanol by integrating biomass to produce heat and power at ethanol plants

    International Nuclear Information System (INIS)

    Kaliyan, Nalladurai; Morey, R. Vance; Tiffany, Douglas G.

    2011-01-01

    A life-cycle assessment (LCA) of corn ethanol was conducted to determine the reduction in the life-cycle greenhouse gas (GHG) emissions for corn ethanol compared to gasoline by integrating biomass fuels to replace fossil fuels (natural gas and grid electricity) in a U.S. Midwest dry-grind corn ethanol plant producing 0.19 hm 3 y -1 of denatured ethanol. The biomass fuels studied are corn stover and ethanol co-products [dried distillers grains with solubles (DDGS), and syrup (solubles portion of DDGS)]. The biomass conversion technologies/systems considered are process heat (PH) only systems, combined heat and power (CHP) systems, and biomass integrated gasification combined cycle (BIGCC) systems. The life-cycle GHG emission reduction for corn ethanol compared to gasoline is 38.9% for PH with natural gas, 57.7% for PH with corn stover, 79.1% for CHP with corn stover, 78.2% for IGCC with natural gas, 119.0% for BIGCC with corn stover, and 111.4% for BIGCC with syrup and stover. These GHG emission estimates do not include indirect land use change effects. GHG emission reductions for CHP, IGCC, and BIGCC include power sent to the grid which replaces electricity from coal. BIGCC results in greater reductions in GHG emissions than IGCC with natural gas because biomass is substituted for fossil fuels. In addition, underground sequestration of CO 2 gas from the ethanol plant's fermentation tank could further reduce the life-cycle GHG emission for corn ethanol by 32% compared to gasoline.

  3. Preliminary Study of Printed Circuit Heat Exchanger (PCHE) for various power conversion systems for SMART

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Jinsu; Baik, Seungjoon; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2016-10-15

    The steam-Rankine cycle was the most widely used power conversion system for a nuclear power plant. The size of the heat exchanger is important for the modulation. Such a challenge was conducted by Kang et al. They change the steam generator type for the SMART from helical type heat exchanger to Printed Circuit Heat Exchanger (PCHE). Recently, there has been a growing interest in the supercritical carbon dioxide (S-CO{sub 2}) Brayton cycle as the most promising power conversion system. The reason is high efficiency with simple layout and compact power plant due to small turbomachinery and compact heat exchanger technology. That is why the SCO{sub 2} Brayton cycle can enhance the existing advantages of Small Modular Reactor (SMR) like SMART, such as reduction in size, capital cost, and construction period. Thermal hydraulic and geometric parameters of a PCHE for the S-CO{sub 2} power cycle coupled to SMART. The results show that the water - CO{sub 2} printed circuit heat exchanger size is smaller than printed circuit steam generator for the superheated steam Rankine cycle. This results show the potential benefit of using the S-CO-2 Brayton power cycle to a water-cooled small modular reactor.

  4. Construction of Shika Nuclear Power Station Unit No.2 of the Hokuriku Electric Power Co., Inc

    International Nuclear Information System (INIS)

    Yamanari, Shozo; Miyahara, Ryohei; Umezawa, Takeshi; Teshiba, Ichiro

    2006-01-01

    Construction of the Shika Nuclear Power Station Unit No.2 of the Hokuriku Electric Power Co., Inc. (advanced boiling-water reactor; output: 1.358 mega watts) was begun in August 1999 and it will resume commercial operation in March 2006 as scheduled. Hitachi contributed effectually toward realizing the project with supply of a complete set of the advanced nuclear reactor and turbine-generator system with the latest design and construction technology in harmony. Large-scale modular structures for installation and a computer-aided engineering system for work procedure and schedule management were applied with the utmost priority placed on work efficiency, safety and quality assurance. (T.Tanaka)

  5. Pt/SnO2-based CO-oxidation catalysts for long-life closed-cycle CO2 lasers

    Science.gov (United States)

    Schryer, David R.; Upchurch, Billy T.; Hess, Robert V.; Wood, George M.; Sidney, Barry D.; Miller, Irvin M.; Brown, Kenneth G.; Vannorman, John D.; Schryer, Jacqueline; Brown, David R.

    1990-01-01

    Noble-metal/tin-oxide based catalysts such as Pt/SnO2 have been shown to be good catalysts for the efficient oxidation of CO at or near room temperature. These catalysts require a reductive pretreatment and traces of hydrogen or water to exhibit their full activity. Addition of Palladium enhances the activity of these catalysts with about 15 to 20 percent Pt, 4 percent Pd, and the balance SnO2 being an optimum composition. Unfortunately, these catalysts presently exhibit significant decay due in part to CO2 retention, probably as a bicarbonate. Research on minimizing the decay in activity of these catalysts is currently in progress. A proposed mechanism of CO oxidation on Pt/SnO2-based catalysts has been developed and is discussed.

  6. Thermodynamic analysis of a nuclear-hydrogen power system using H2/O2 direct combustion product as a working substance in the bottom cycle

    International Nuclear Information System (INIS)

    Chen, D.Z.; Yu, C.P.

    1990-01-01

    A combined thermodynamic cycle using nuclear and hydrogen energy as heat sources was investigated in this paper. The cycle is composed of top cycle using HTGR as energy source and helium as working medium and a bottom cycle with H 2 /O 2 direct combustion product as working substance. hydrogen and oxygen are thermochemically by splitting of water produced through a part of nuclear heat recovered from the top cycle. They may be delivered to the O 2 /H 2 users or used as fuels for the high temperature bottom Rankine steam cycle. The combined cycle not only uses the new energy sources instead of conventional fossil fuels but it possess the advantages of both helium and steam cycle. It has a high thermal efficiency, large unit capacity, many-sided usage and less pollution. It may represent a new type of combined cycles for future energy conversion and power generation. Using computer diagram, a variety of schemes were calculated and analyzed. The influence of some main parameters upon the cycle performance were also studied

  7. Advanced Accelerated Power Cycling Test for Reliability Investigation of Power Device Modules

    DEFF Research Database (Denmark)

    Choi, Uimin; Jørgensen, Søren; Blaabjerg, Frede

    2016-01-01

    This paper presents an apparatus and methodology for an advanced accelerated power cycling test of insulated-gate bipolar transistor (IGBT) modules. In this test, the accelerated power cycling test can be performed under more realistic electrical operating conditions with online wear-out monitoring...... of tested power IGBT module. The various realistic electrical operating conditions close to real three-phase converter applications can be achieved by the simple control method. Further, by the proposed concept of applying the temperature stress, it is possible to apply various magnitudes of temperature...... swing in a short cycle period and to change the temperature cycle period easily. Thanks to a short temperature cycle period, test results can be obtained in a reasonable test time. A detailed explanation of apparatus such as configuration and control methods for the different functions of accelerated...

  8. Experimental and Numerical Analysis of S-CO2 Critical Flow for SFR Recovery System Design

    International Nuclear Information System (INIS)

    Kim, Min Seok; Jung, Hwa-Young; Ahn, Yoonhan; Lee, Jekyoung; Lee, Jeong Ik

    2016-01-01

    This paper presents both numerical and experimental studies of the critical flow of S-CO 2 while special attention is given to the turbo-machinery seal design. A computational critical flow model is described first. The experiments were conducted to validate the critical flow model. Various conditions have been tested to study the flow characteristic and provide validation data for the model. The comparison of numerical and experimental results of S-CO 2 critical flow will be presented. In order to eliminate SWR, a concept of coupling the Supercritical CO 2 (S-CO 2 ) cycle with SFR has been proposed. It is known that for a closed system controlling the inventory is important for stable operation and achieving high efficiency. Since the S-CO 2 power cycle is a highly pressurized system, certain amount of leakage flow is inevitable in the rotating turbo-machinery via seals. To simulate the CO 2 leak flow in a turbo-machinery with higher accuracy in the future, the real gas effect and friction factor will be considered for the CO 2 critical flow model. Moreover, experimentally obtained temperature data were somewhat different from the numerically obtained temperature due to the insufficient insulation and large thermal inertia of the CO 2 critical flow facility. Insulation in connecting pipes and the low-pressure tank will be added and additional tests will be conducted

  9. 1.5 °C carbon budget dependent on carbon cycle uncertainty and future non-CO2 forcing.

    Science.gov (United States)

    Mengis, Nadine; Partanen, Antti-Ilari; Jalbert, Jonathan; Matthews, H Damon

    2018-04-11

    Estimates of the 1.5 °C carbon budget vary widely among recent studies, emphasizing the need to better understand and quantify key sources of uncertainty. Here we quantify the impact of carbon cycle uncertainty and non-CO 2 forcing on the 1.5 °C carbon budget in the context of a prescribed 1.5 °C temperature stabilization scenario. We use Bayes theorem to weight members of a perturbed parameter ensemble with varying land and ocean carbon uptake, to derive an estimate for the fossil fuel (FF) carbon budget of 469 PgC since 1850, with a 95% likelihood range of (411,528) PgC. CO 2 emissions from land-use change (LUC) add about 230 PgC. Our best estimate of the total (FF + LUC) carbon budget for 1.5 °C is therefore 699 PgC, which corresponds to about 11 years of current emissions. Non-CO 2 greenhouse gas and aerosol emissions represent equivalent cumulative CO 2 emissions of about 510 PgC and -180 PgC for 1.5 °C, respectively. The increased LUC, high non-CO 2 emissions and decreased aerosols in our scenario, cause the long-term FF carbon budget to decrease following temperature stabilization. In this scenario, negative emissions would be required to compensate not only for the increasing non-CO 2 climate forcing, but also for the declining natural carbon sinks.

  10. THE CALVIN CYCLE ENZYME PHOSPHOGLYCERATE KINASE OF XANTHOBACTER-FLAVUS REQUIRED FOR AUTOTROPHIC CO2 FIXATION IS NOT ENCODED BY THE CBB OPERON

    NARCIS (Netherlands)

    MEIJER, WG

    1994-01-01

    During autotrophic growth of Xanthobacter flavus, energy derived from the oxidation of hydrogen methanol or formate is used to drive the assimilation of CO2 via the Calvin cycle. The genes encoding the Calvin cycle enzymes are organized in the cbb operon, which is expressed only during autotrophic

  11. NO reduction by CO over noble-metal catalysts under cycled feedstreams

    International Nuclear Information System (INIS)

    Muraki, H.; Fujitani, Y.

    1986-01-01

    The reduction of NO with CO was studied over α-Al/sub 2/O/sub 3/-supported Pt, Pd, Rh, Ru, and Ir catalysts. The activities were measured by using cycled feeds and steady noncycled feed. The activity sequence of the catalysts tested was Rh > Ru > Ir > Pd > Pt. The activities of Pt and Pd catalysts were increased under the cycled feed. The periodic operation effect on the Pt catalyst was more predominant than that on the Pd catalyst. The order of periodic operation effect corresponded to the order of their susceptibility to CO self-poisoning

  12. Study on CO2 global recycling system

    International Nuclear Information System (INIS)

    Takeuchi, M.; Sakamoto, Y.; Niwa, S.

    2001-01-01

    In order to assist in finding ways to mitigate CO 2 emission and to slow the depletion of fossil fuels we have established and evaluated a representative system, which consists of three technologies developed in our laboratory. These technologies were in CO 2 recovery, hydrogen production and methanol synthesis and in addition we established the necessary supporting systems. Analysis of outline designs of the large scale renewable energy power generation system and this system and energy input for building plant, energy input for running plant has been conducted based on a case using this system for a 1000-MW coal fired power plant, followed by an evaluation of the material balance and energy balance. The results are as follows. Energy efficiency is 34%, the CO 2 reduction rate is 41%, the balance ratio of the energy and CO 2 of the system is 2.2 and 1.8, respectively, on the assumption that the primary renewable energy is solar thermal power generation, the stationary CO 2 emission source is a coal-fired power plant and the generation efficiency of the methanol power plant is 60%. By adopting the system, 3.7 million tons of CO 2 can be recovered, approximately 2.7 million tons of methanol can be produced, and 15.4 billion kWh of electricity can be generated per year. Compared to generating all electrical power using only coal, approximately 2.6 million tons of coal per year can be saved and approximately 2.15 million tons of CO 2 emission can be reduced. Therefore, it is clearly revealed that this system would be effective to reduce CO 2 emissions and to utilize renewable energy

  13. Design of an Optical System for High Power CO2 Laser Cutting

    DEFF Research Database (Denmark)

    de Lange, D.F.; Meijer, J.; Nielsen, Jakob Skov

    2003-01-01

    The results of a design study for the optical system for cutting with high power CO2 lasers (6 kW and up) will be presented. As transparent materials cannot be used for these power levels, mirrors have been applied. A coaxial cutting gas supply has been designed with a laser beam entrance into th...... independent of the entering beam angle or position. manufacturing tolerances have been compensated in a one time adjustment during the assembly of the optical system. Preliminary cutting results in 13 mm thick steel in a shipyard application show a signinficant improvement in the cutting performance....

  14. Modelling of electricity generation of large interconnected power systems: How can a CO2 tax influence the European generation mix

    International Nuclear Information System (INIS)

    Voorspools, Kris R.; D'haeseleer, William D.

    2006-01-01

    This paper discusses a methodology for detailed modelling of electricity generation of large interconnected power systems in a liberalised market. The resulting model, called E-Simulate, respects the technological restrictions and boundary conditions inherent to power generation and simulates the power generation and cross border trade on an hourly basis and on a power plant level. Nevertheless, E-Simulate is sufficiently flexible, transparent and fast. It is a valid, objective and useful tool in the simulation of the impact of power generation topics in the context of liberalised markets and GHG emission reduction. As a comprehensive example of the use and the strength of E-Simulate, we study the effect of a CO 2 tax on power generation and electricity trade in and between eight interconnected European zones: The Netherlands, Belgium/Luxemburg, France, Germany, Spain, Portugal, Switzerland and Italy. A CO 2 tax of 10 Euro /ton CO 2 causes an overall CO 2 emission reduction of about 6%. We notice an overall increase in gas fired generation and a corresponding reduction of coal and lignite fired generation on a trans-national level. In some zones (The Netherlands, Belgium/Luxemburg and Italy), the emissions will rise. In others (France, Germany and Spain), emissions will decrease. This is a result of the CO 2 tax that not only causes a shift towards fuels with lower carbon content but also, and correspondingly, leads to a redistribution of cross border trade

  15. [Effects of drying and wetting cycles induced by tides on net ecosystem exchange of CO2 over a salt marsh in the Yellow River Delta, China.

    Science.gov (United States)

    He, Wen Jun; Han, Guang Xuan; Xu, Yan Ning; Zhang, Xi Tao; Wang, An Dong; Che, Chun Guang; Sun, Bao Yu; Zhang, Xiao Shuai

    2018-01-01

    As a unique hydrological characteristic, the tidal action can strongly affect carbon balance in a salt marsh despite their short duration. Using the eddy covariance technique, we measured the net ecosystem CO 2 exchange (NEE) and its environmental factors and tidal change over a salt marsh in the Yellow River Delta. It aimed to investigate the effect of tidal process and drying and wetting cycles induced by tides on NEE. The results showed that the tidal process promoted the daytime CO 2 uptake, but it didn't clearly affect the nighttime CO 2 release. Tidal inundation was a major factor influencing daytime NEE. The diurnal change of NEE showed a distinct U-shaped curve on both drought and wet stages, but not with substantial variation in its amplitude during the drought stage. The drying and wetting cycles enhanced the absorption of daytime CO 2 . Under drought stage, the mean of the maximum photosynthetic rate (A max ), apparent quantum yield (α) and ecosystem respiration (R eco ) were higher than those in wet stage. In addition, the drying and wetting cycles suppressed the nighttime CO 2 release from the salt marsh but increased its temperature sensitivity.

  16. Thermo-economic performance of HTGR Brayton power cycles

    International Nuclear Information System (INIS)

    Linares, J. L.; Herranz, L. E.; Moratilla, B. Y.; Fernandez-Perez, A.

    2008-01-01

    High temperature reached in High and Very High Temperature Reactors (VHTRs) results in thermal efficiencies substantially higher than those of actual nuclear power plants. A number of studies mainly driven by achieving optimum thermal performance have explored several layout. However, economic assessments of cycle power configurations for innovative systems, although necessarily uncertain at this time, may bring valuable information in relative terms concerning power cycle optimization. This paper investigates the thermal and economic performance direct Brayton cycles. Based on the available parameters and settings of different designs of HTGR power plants (GTHTR-300 and PBMR) and using the first and second laws of thermodynamics, the effects of compressor inter-cooling and of the compressor-turbine arrangement (i.e., single vs. multiple axes) on thermal efficiency have been estimated. The economic analysis has been based on the El-Sayed methodology and on the indirect derivation of the reactor capital investment. The results of the study suggest that a 1-axis inter-cooled power cycle has a similar thermal performance to the 3-axes one (around 50%) and, what's more, it is substantially less taxed. A sensitivity study allowed assessing the potential impact of optimizing several variables on cycle performance. Further than that, the cycle components costs have been estimated and compared. (authors)

  17. Analysis of the CO2 emissions and of the other characteristics of the European market of new passenger cars. 2. Segment analysis

    International Nuclear Information System (INIS)

    Zervas, Efthimios

    2010-01-01

    This article analyzes the engine and vehicle characteristics and the CO 2 emissions of the new passenger cars for all segments of the European market. As in the first article of this work, the target is to find the real market parameters influencing exhaust CO 2 emissions. The present analysis is focused on the segment sales distribution (EU average and within each country) and also in four parameters of each segment influencing CO 2 emissions: average vehicle weight, average engine capacity, average maximum and specific power. The second part of this work concerns the CO 2 emissions of each segment on the New European Driving Cycle and its urban and extra urban parts.

  18. Role of Atmospheric CO2 in the Ice Ages (Invited)

    Science.gov (United States)

    Toggweiler, J. R.

    2010-12-01

    Ice cores from Antarctica provide our most highly resolved records of glacial-interglacial climate change. They feature big transitions every 100,000 years or so in which Antarctica warms by up to 10 deg. C while the level of atmospheric CO2 rises by up to 100 ppm. We have no other records like these from any other location, so the assumption is often made that the Earth's mean temperature varies like the temperatures in Antarctica. The striking co-variation between the two records is taken to mean 1) that there is a causal relationship between the global temperature and atmospheric CO2 and 2) that atmospheric CO2 is a powerful agent of climate change during the ice ages. The problem is that the mechanism most often invoked to explain the CO2 variations operates right next to Antarctica and, as such, provides a fairly direct way to explain the temperature variations in Antarctica as well. If so, Antarctic temperatures go up and down for the same reason that atmospheric CO2 goes up and down, in which case no causation can be inferred. Climate models suggest that the 100-ppm CO2 increases during the big transitions did not increase surface temperatures by more than 2 deg. C. This is not nearly enough to explain the observed variability. A better reason for thinking that atmospheric CO2 is important is that its temporal variations are concentrated in the 100,000-yr band. In my presentation I will argue that atmospheric CO2 is important because it has the longest time scale in the system. We observe empirically that atmospheric CO2 remains low for 50,000 years during the second half of each 100,000-yr cycle. The northern ice sheets become especially large toward the ends of these intervals, and it is large ice sheets that make the Earth especially cold. This leads me to conclude that atmospheric CO2 is important because of its slow and persistent influence on the northern ice sheets over the second half of each 100,000-yr cycle.

  19. Heat exchanger inventory cost optimization for power cycles with one feedwater heater

    International Nuclear Information System (INIS)

    Qureshi, Bilal Ahmed; Antar, Mohamed A.; Zubair, Syed M.

    2014-01-01

    Highlights: • Cost optimization of heat exchanger inventory in power cycles is investigated. • Analysis for an endoreversible power cycle with an open feedwater heater is shown. • Different constraints on the power cycle are investigated. • The constant heat addition scenario resulted in the lowest value of the cost function. - Abstract: Cost optimization of heat exchanger inventory in power cycles with one open feedwater heater is undertaken. In this regard, thermoeconomic analysis for an endoreversible power cycle with an open feedwater heater is shown. The scenarios of constant heat rejection and addition rates, power as well as rate of heat transfer in the open feedwater heater are studied. All cost functions displayed minima with respect to the high-side absolute temperature ratio (θ 1 ). In this case, the effect of the Carnot temperature ratio (Φ 1 ), absolute temperature ratio (ξ) and the phase-change absolute temperature ratio for the feedwater heater (Φ 2 ) are qualitatively the same. Furthermore, the constant heat addition scenario resulted in the lowest value of the cost function. For variation of all cost functions, the smaller the value of the phase-change absolute temperature ratio for the feedwater heater (Φ 2 ), lower the cost at the minima. As feedwater heater to hot end unit cost ratio decreases, the minimum total conductance required increases

  20. A technical, economic, and environmental assessment of amine-based CO2 capture technology for power plant greenhouse gas control.

    Science.gov (United States)

    Rao, Anand B; Rubin, Edward S

    2002-10-15

    Capture and sequestration of CO2 from fossil fuel power plants is gaining widespread interest as a potential method of controlling greenhouse gas emissions. Performance and cost models of an amine (MEA)-based CO2 absorption system for postcombustion flue gas applications have been developed and integrated with an existing power plant modeling framework that includes multipollutant control technologies for other regulated emissions. The integrated model has been applied to study the feasibility and cost of carbon capture and sequestration at both new and existing coal-burning power plants. The cost of carbon avoidance was shown to depend strongly on assumptions about the reference plant design, details of the CO2 capture system design, interactions with other pollution control systems, and method of CO2 storage. The CO2 avoidance cost for retrofit systems was found to be generally higher than for new plants, mainly because of the higher energy penalty resulting from less efficient heat integration as well as site-specific difficulties typically encountered in retrofit applications. For all cases, a small reduction in CO2 capture cost was afforded by the SO2 emission trading credits generated by amine-based capture systems. Efforts are underway to model a broader suite of carbon capture and sequestration technologies for more comprehensive assessments in the context of multipollutant environmental management.