WorldWideScience

Sample records for dioxide transcritical power

  1. Low temperature heat source for power generation: Exhaustive analysis of a carbon dioxide transcritical power cycle

    International Nuclear Information System (INIS)

    Velez, Fredy; Segovia, Jose; Chejne, Farid; Antolin, Gregorio; Quijano, Ana; Carmen Martin, M.

    2011-01-01

    The main results of a theoretical work on the use of a low temperature heat source for power generation through a carbon dioxide transcritical power cycle are reported in this paper. The procedure for analyzing the behaviour of the proposed cycle consisted in modifying the input pressure to the turbine from 66 bar, maintained constant each evaluated temperature (60 o C, 90 o C, 120 o C and 150 o C) until the net work was approximately zero. As a result, the maximum exergy efficiency was 50%, while the energy efficiencies obtained were 9.8%, 7.3%, 4.9% and 2.4% and the net specific work was 18.2 kJ/kg, 12.8 kJ/kg, 7.8 kJ/kg and 3.5 kJ/kg, respectively. Furthermore, the effect of the addition of an internal heat exchanger, which obviously supposed an increase in the efficiency, was analyzed. The analysis of the proposed system shows the viability of implementing this type of process as an energy alternative and/or strengthener of non-conventional energy sources in non-provided zones, or for increasing the energy efficiency in the industry. -- Highlights: → Energy and exergy analysis of a carbon dioxide transcritical power cycle is reported. → The effect of the inlet temperature to the turbine is evaluated. → Conditions of maximum efficiency and maximum net work are compared. → The inclusion of an IHX is also analysed.

  2. Analysis of a carbon dioxide transcritical power cycle using a low temperature source

    International Nuclear Information System (INIS)

    Cayer, Emmanuel; Galanis, Nicolas; Desilets, Martin; Nesreddine, Hakim; Roy, Philippe

    2009-01-01

    A detailed analysis of a carbon dioxide transcritical power cycle using an industrial low-grade stream of process gases as its heat source is presented. The methodology is divided in four steps: energy analysis, exergy analysis, finite size thermodynamics and calculation of the heat exchangers' surface. The results have been calculated for fixed temperature and mass flow rate of the heat source, fixed maximum and minimum temperatures in the cycle and a fixed sink temperature by varying the high pressure of the cycle and its net power output. The main results show the existence of an optimum high pressure for each of the four steps; in the first two steps, the optimum pressure maximises the thermal or exergetic efficiency while in the last two steps it minimises the product UA or the heat exchangers' surface. These high pressures are very similar for the energy and exergy analyses. The last two steps also have nearly identical optimizing high pressures that are significantly lower that the ones for the first two steps. In addition, the results show that the augmentation of the net power output produced from the limited energy source has no influence on the results of the energy analysis, decreases the exergetic efficiency and increases the heat exchangers' surface. Changing the net power output has no significant impact on the high pressures optimizing each of the four steps

  3. Multi-objective optimization of the carbon dioxide transcritical power cycle with various configurations for engine waste heat recovery

    International Nuclear Information System (INIS)

    Tian, Hua; Chang, Liwen; Shu, Gequn; Shi, Lingfeng

    2017-01-01

    Highlights: • A systematic optimization methodology is presented for carbon dioxide power cycle. • Adding the regenerator is a significant means to improve the system performance. • A decision making based on the optimization results is conducted in depth. • Specific optimal solutions are selected from Pareto fronts for different demands. - Abstract: In this paper, a systematic multi-objective optimization methodology is presented for the carbon dioxide transcritical power cycle with various configurations used in engine waste heat recovery to generate more power efficiently and economically. The parametric optimization is performed for the maximum net power output and exergy efficiency, as well as the minimum electricity production cost by using the genetic algorithm. The comparison of the optimization results shows the thermodynamic performance can be most enhanced by simultaneously adding the preheater and regenerator based on the basic configuration, and the highest net power output and exergy efficiency are 25.89 kW and 40.95%, respectively. Meanwhile, the best economic performance corresponding to the lowest electricity production cost of 0.560$/kW·h is achieved with simply applying an additional regenerator. Moreover, a thorough decision making is conducted for a further screening of the obtained optimal solutions. A most preferred Pareto optimal solution or a representative subset of the Pareto optimal solutions is obtained according to additional subjective preferences while a referential optimal solution is also provided on the condition of no additional preference.

  4. Optimal heat rejection pressure in transcritical carbon dioxide air conditioning and heat pump systems

    DEFF Research Database (Denmark)

    Liao, Shengming; Jakobsen, Arne

    1998-01-01

    Due to the urgent need for environmentally benign refrigerants, the use of the natural substance carbon dioxide in refrigeration systems has gained more and more attention. In systems such as automobile air-conditioners and heat pumps, owing to the relatively high heat rejection temperatures, the...... dioxide air conditioning or heat pump systems and for intelligent controlling such systems.......Due to the urgent need for environmentally benign refrigerants, the use of the natural substance carbon dioxide in refrigeration systems has gained more and more attention. In systems such as automobile air-conditioners and heat pumps, owing to the relatively high heat rejection temperatures......, the cycles using carbon dioxide as refrigerant will have to operate in the transcritical area. In a transcritical carbon dioxide system, there is an optimal heat rejection pressure that gives a maximum COP. In this paper, it is shown that the value of this optimal heat rejection pressure mainly depends...

  5. Binary blend of carbon dioxide and fluoro ethane as working fluid in transcritical heat pump systems

    Directory of Open Access Journals (Sweden)

    Zhang Xian-Ping

    2015-01-01

    Full Text Available As an eco-friendly working fluid, carbon dioxide or R744 is expected to substitute for the existing working fluids used in heat pump systems. It is, however, challenged by the much higher heat rejection pressure in transcritical cycle compared with the traditional subcritical cycle using freons. There exists a worldwide tendency to utilize blend refrigerants as alternatives. Therefore, a new binary blend R744/R161 in this research is proposed in order to decrease the heat rejection pressure. Meanwhile, on mixing R744 with R161, the flammability and explosivity of R161 can be suppressed because of the extinguishing effect of R744. A transcritical thermodynamic model is developed, and then the system performances of heat pump using R744/R161 blend are investigated and compared with those of pure R744 system under the same operation conditions. The variations of heat rejection pressure, heating coefficient of performance, unit volumetric heating capacity, discharge temperature of compressor and the mass fraction of R744/R161 are researched. The results show that R744/R161 mixture can reduce the heat rejection pressure of transcritical heat pump system.

  6. Numerical simulation of trans-critical carbon dioxide (R744) flow through short tube orifices

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Valladares, O. [Centro de Investigacion en Energia de la Universidad Nacional Autonoma de Mexico, Privada Xochicalco S/N, Apdo. Postal 34, 62580 Temixco, Morelos (Mexico)

    2006-02-01

    A detailed one-dimensional numerical simulation of the fluid-dynamic behaviour of short tube orifices expansion devices working with trans-critical carbon dioxide (CO{sub 2} or R744) has been developed. The discretized governing equations are coupled using an implicit step by step method. A special treatment has been implemented in order to consider transitions (subcooled liquid region and equilibrium two-phase region). The numerical model allows analysis of aspects such as geometry, different working conditions, critical or non-critical flow conditions, etc. Comparison of the numerical simulation with experimental data presented in the technical literature will be shown in the present article. (author)

  7. Design and experimental analysis of a carbon dioxide transcritical chiller for commercial refrigeration

    International Nuclear Information System (INIS)

    Cecchinato, Luca; Chiarello, Manuel; Corradi, Marco

    2010-01-01

    Carbon dioxide is an interesting solution for commercial refrigeration and in perspective for air-conditioning systems. In this paper a newly developed carbon dioxide transcritical air cooled chiller for refrigerating propylene glycol down to -8 o C supply temperature is described. The aim of the project was at optimising the cycle energy efficiency while assuring reliable operation and simple management of the unit. The carbon dioxide optimal pressure issue is addressed with an innovate system architecture and control logic. Using a flash tanks and two electronic valves, the optimal cycle upper pressure was maintained in transcritical operation mode. The managing of the valves allows the refrigeration machine efficiency improvement when the gas cooler inlet air allows subcritical working conditions. A simulation model of the chiller was developed and its results validated with experimental data. A measurement campaign was carried out, testing the chiller at external temperatures ranging from 18 to 35 o C, the unit energy efficiency ranging from 3.1 to 2.0.

  8. Exergy analysis of transcritical carbon dioxide refrigeration cycle with an expander

    International Nuclear Information System (INIS)

    Yang Junlan; Ma Yitai; Li Minxia; Guan Haiqing

    2005-01-01

    In this paper, a comparative study is performed for the transcritical carbon dioxide refrigeration cycles with a throttling valve and with an expander, based on the first and second laws of thermodynamics. The effects of evaporating temperature and outlet temperature of gas cooler on the optimal heat rejection pressure, the coefficients of performance (COP), the exergy losses, and the exergy efficiencies are investigated. In order to identify the amounts and locations of irreversibility within the two cycles, exergy analysis is employed to study the thermodynamics process in each component. It is found that in the throttling valve cycle, the largest exergy loss occurs in the throttling valve, about 38% of the total cycle irreversibility. In the expander cycle, the irreversibility mainly comes from the gas cooler and the compressor, approximately 38% and 35%, respectively. The COP and exergy efficiency of the expander cycle are on average 33% and 30% higher than those of the throttling valve cycle, respectively. It is also concluded that an optimal heat rejection pressure can be obtained for all the operating conditions to maximize the COP. The analysis results are of significance to provide theoretical basis for optimization design and operation control of the transcritical carbon dioxide cycle with an expander

  9. Theoretical analysis of a transcritical power cycle for power generation from waste energy at low temperature heat source

    International Nuclear Information System (INIS)

    Vélez, Fredy; Chejne, Farid; Antolin, Gregorio; Quijano, Ana

    2012-01-01

    The present paper reports the results obtained on a carbon dioxide transcritical power cycle using an energy and exergy analysis. The procedure consisted of modifying the inlet pressure to the turbine from 66 bar, by means of the software HYSYS®, maintaining constant each evaluated turbine inlet temperature (60, 90, 120 and 150 °C) until the net work was approximately zero. As a result, an increase up to 25% for the exergy efficiency, and up to 300% for the energy efficiency are obtained when the inlet temperature to the turbine is risen from 60 to 150 °C. Consequently, the analysis shows the viability of implementing this process as alternative energy, because of the possibility to recovery energy from waste heat from industrial processes.

  10. Thermodynamic performance evaluation of transcritical carbon dioxide refrigeration cycle integrated with thermoelectric subcooler and expander

    International Nuclear Information System (INIS)

    Dai, Baomin; Liu, Shengchun; Zhu, Kai; Sun, Zhili; Ma, Yitai

    2017-01-01

    New configurations of transcritical CO_2 refrigeration cycle combined with a thermoelectric (TE) subcooler and an expander (TES+EXP_H_M and TES+EXP_M_L) are proposed. The expander can operate between the high-pressure to the vessel pressure, or from vessel pressure to evaporation pressure. A power system is utilized to balance and supply power to thermoelectric subcooler and compressor. Thermodynamic performance optimizations and analyses are presented. Comparisons are carried out with the BASE, EXP_H_M, EXP_M_L, and TES cycles. The results show that the coefficient of performance (COP) improvement is more notable when the expander is installed between the liquid receiver and the evaporator. Maximum COP is obtained for the new cycles with a simultaneous optimization of discharge pressure and subcooling temperature. The new proposed TES+EXP_M_L cycle shows an excellent and steady performance than other cycles. It operates not only with the highest COP, but also the lowest discharge pressure. Under the working conditions of high gas cooler outlet temperature or low evaporation temperature, the merits of COP improvement and discharge pressure reduction are more prominent. The new cycle is more suitable for the hot regions where the CO_2 can not be sufficiently subcooled or the refrigerated space operates at low evaporation temperature. - Highlights: • New configurations of transcritical CO_2 refrigeration cycle are proposed. • New cycles are optimized and compared with other cycles. • The position of expander has an evident influence on the performance of CO_2 cycle. • TES+EXP_M_L cycle shows the highest COP and lowest discharge pressure. • The range of application for the TES+EXP_M_L cycle is recommended.

  11. 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%.

  12. Experimental performance evaluation for a carbon dioxide light commercial cooling application under transcritical and subcritical conditions

    International Nuclear Information System (INIS)

    Boccardi, G.; Calabrese, N.; Celata, G.P.; Mastrullo, R.; Mauro, A.W.; Perrone, A.; Trinchieri, R.

    2013-01-01

    CO 2 is one of the most interesting non toxic, nor flammable, low GWP natural fluid to be used in applications with a large direct contribution to global warming, such as vending machines. In this paper the results of an experimental investigation on a small capacity, air-forced refrigerating plant working with CO 2 are presented. The air inlet temperatures at gas cooler and evaporator were varied between 16 °C and 31 °C and between −25 °C and 25 °C, respectively, to cover the range of temperatures under conditions typical of commercial refrigeration, during quasi-steady operation. The thermodynamic analysis of the system performance was carried on varying independently the pressure at the gas cooler, by overfeeding the liquid receiver to point out the effect of refrigerant charge. The results allow to describe the performance of the system in a map varying the boundary conditions; at the same time the corresponding variations of the thermodynamic cycle, the COP and the mass flow rate are reported. -- Highlights: ► A light commercial refrigerating plant working with CO 2 was tested in order to evaluate its performance. ► 71 experimental points were collected varying the flow rates, the temperatures of air sources and the refrigerant charge. ► Mass flow rate, cooling capacity, electrical power and COP were evaluated as a function of pressures and superheating. ► The segregate influence of each operating parameter on each performance indicator was calculated. ► A map of plant performance as a function of air source temperatures is reported

  13. 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

  14. 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

  15. System design and analysis of the trans-critical carbon-dioxide automotive air-conditioning system.

    Science.gov (United States)

    Mu, Jing-Yang; Chen, Jiang-Ping; Chen, Zhi-Jiu

    2003-01-01

    As an environmentally harmless and feasible alternate refrigerant, CO2 has attracted worldwide attention, especially in the area of automobile air-conditioning (AAC). The thermal property of CO2 and its trans-critical refrigeration cycle is very different from that of the traditional CFC or HCFC system. The detailed process of CO2 system thermal cycle design and optimization is described in this paper. System prototype and performance test bench were developed to analyze the performance of the CO2 AAC system.

  16. 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

  17. Modeling and analysis of a transcritical rankine power cycle with a low grade heat source

    DEFF Research Database (Denmark)

    Nguyen, Chan; Veje, Christian

    efficiency, exergetic efficiency and specific net power output. A generic cycle configuration has been used for analysis of a geothermal energy heat source. This model has been validated against similar calculations using industrial waste heat as the energy source. Calculations are done with fixed...

  18. Optimization of Biomass-Fuelled Combined Cooling, Heating and Power (CCHP Systems Integrated with Subcritical or Transcritical Organic Rankine Cycles (ORCs

    Directory of Open Access Journals (Sweden)

    Daniel Maraver

    2014-04-01

    Full Text Available This work is focused on the thermodynamic optimization of Organic Rankine Cycles (ORCs, coupled with absorption or adsorption cooling units, for combined cooling heating and power (CCHP generation from biomass combustion. Results were obtained by modelling with the main aim of providing optimization guidelines for the operating conditions of these types of systems, specifically the subcritical or transcritical ORC, when integrated in a CCHP system to supply typical heating and cooling demands in the tertiary sector. The thermodynamic approach was complemented, to avoid its possible limitations, by the technological constraints of the expander, the heat exchangers and the pump of the ORC. The working fluids considered are: n-pentane, n-heptane, octamethyltrisiloxane, toluene and dodecamethylcyclohexasiloxane. In addition, the energy and environmental performance of the different optimal CCHP plants was investigated. The optimal plant from the energy and environmental point of view is the one integrated by a toluene recuperative ORC, although it is limited to a development with a turbine type expander. Also, the trigeneration plant could be developed in an energy and environmental efficient way with an n-pentane recuperative ORC and a volumetric type expander.

  19. A quasi-transient model of a transcritical carbon dioxide direct-expansion ground source heat pump for space and water heating

    International Nuclear Information System (INIS)

    Eslami-Nejad, Parham; Ouzzane, Mohamed; Aidoun, Zine

    2015-01-01

    In this study, a theoretical quasi-transient model is developed for detailed simulations of a carbon dioxide (CO_2) direct-expansion ground source heat pump (DX-GSHP). This model combines a transient analytical model for the ground, steady-state numerical models for the borehole and the gas cooler, as well as several thermodynamic models for the remaining components of a conventional heat pump, organized in interacting subroutines to form a powerful simulation tool. Extensive validation combining experimental data and CFD-generated results was performed for the borehole before the tool was used to simulate a practical application case. Performance is investigated for a system satisfying both space heating and domestic hot water requirements of a typical single family detached home in a cold climate region. The variation of different system parameters is also evaluated in this study. It is shown that CO_2 DX-GSHPs can offer relatively efficient and stable performance for integrated water and space heating applications. Furthermore, the importance of an accurate geothermal borehole sizing is highlighted for the DX-CO_2 heat pump systems. It is shown that, due to changes in the system working conditions, the total borehole length is not linearly correlated with the heat pump energy consumption and other parameters such as heat pump coefficient of performance and pressure drop in ground heat exchangers. Results showed that increasing the total borehole length of an optimum design (reference case study) by 25% decreases the total annual energy consumption by only 6%. However, reducing total borehole length of the reference case by 25% increases the total annual energy consumption by 10%. - Highlights: • A quasi-transient model for CO_2 direct-exchange ground-source heat pump is developed. • Validation combining experimental data and CFD-generated results was performed. • The effect of the borehole size on the design parameters is evaluated. • Results show that

  20. Super- and Transcritical Fluid Expansions for Next-Generation Energy Conversion Systems

    NARCIS (Netherlands)

    Harinck, J.

    2010-01-01

    The next generation of thermodynamic power cycles offers great potential as the conceptual basis for sustainable energy converters. Examples are the supercritical and superheated Organic Rankine cycle, the transcritical condensation cycle, the supercritical Brayton cycle, the Organic Stirling cycle

  1. 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.

  2. Experimental sizing and assessment of two-phase pressure drop correlations for a capillary tube with transcritical and subcritical carbon dioxide flow

    International Nuclear Information System (INIS)

    Trinchieri, R; Boccardi, G; Calabrese, N; Zummo, G; Celata, G P

    2014-01-01

    In the last years, CO 2 was proposed as an alternative refrigerant for different refrigeration applications (automotive air conditioning, heat pumps, refrigerant plants, etc.) In the case of low power refrigeration applications, as a household refrigerator, the use of too expensive components is not economically sustainable; therefore, even if the use of CO 2 as the refrigerant is desired, it is preferable to use conventional components as much as possible. For these reasons, the capillary tube is frequently proposed as expansion system. Then, it is necessary to characterize the capillary in terms of knowledge of the evolving mass flow rate and the associate pressure drop under all possible operative conditions. For this aim, an experimental campaign has been carried out on the ENEA test loop 'CADORE' to measure the performance of three capillary tubes having same inner diameter (0.55 mm) but different lengths (4, 6 and 8 meters). The test range of inlet pressure is between about 60 and 110 bar, whereas external temperatures are between about 20 to 42 °C. The two-phase pressure drop through the capillary tube is detected and experimental values are compared with the predictions obtained with the more widely used correlations available in the literature. Correlations have been tested over a wide range of variation of inlet flow conditions, as a function of different inlet parameters.

  3. 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

  4. Studies on carbon dioxide power plant, (3)

    International Nuclear Information System (INIS)

    Akagawa, Koji; Fujii, Terushige; Sakaguchi, Tadashi; Kawabata, Yasusuke; Kuroda, Toshihiro.

    1980-01-01

    A power generating plant using carbon dioxide instead of water has been studied by the authors, as high efficiency can be obtained in high temperature range (higher than 650 deg C) and turbines become compact as compared with the Rankine steam cycle. In this paper, the theoretical analysis of the dynamic characteristics of this small power generating plant of supercritical pressure and the comparison with the experimental results are reported. In the theoretical analysis, the linear approximation method using small variation method was adopted for solution. Every component was modeled as the concentrated constant system, and the transfer function for each component was determined, then simulation was carried out for the total system synthesizing these components. The approximation of physical values, and the analysis of a plunger pump, a regenerator, a heater, a vapor valve, a turbine and a blower, piping, and pressure drop are described. The response to the stepwise changes of heating, flow rate, opening of a vapor valve and a load control valve for a blower was investigated. The theoretical anaysis and the experimental results were in good agreement, and this analysis is applicable to the carbon dioxide plant of practical scale. (Kako, I.)

  5. Nuclear power and carbon dioxide free automobiles

    International Nuclear Information System (INIS)

    Pendergast, D.R.

    1999-01-01

    Nuclear energy has been developed as a major source of electric power in Canada. Electricity from nuclear energy already avoids the emission of about 100 million tonnes of carbon dioxide to the atmosphere in Canada. This is a significant fraction of the 619 million tonnes of Canadian greenhouse gas emissions in 1995. However, the current scope of application of electricity to end use energy needs in Canada limits the contribution nuclear energy can make to carbon dioxide emission reduction. Nuclear energy can also contribute to carbon dioxide emissions reduction through expansion of the use of electricity to less traditional applications. Transportation, in particular contributed 165 million tonnes of carbon dioxide to the Canadian atmosphere in 1995. Canada's fleet of personal vehicles consisted of 16.9 million cars and light trucks. These vehicles were driven on average 21,000 km/year and generated 91 million tonnes of greenhouse gases expressed as a C02 equivalent. Technology to improve the efficiency of cars is under development which is expected to increase the energy efficiency from the 1995 level of about 10 litres/100 km of gasoline to under 3 litres/100km expressed as an equivalent referenced to the energy content of gasoline. The development of this technology, which may ultimately lead to the practical implementation of hydrogen as a portable source of energy for transportation is reviewed. Fuel supply life cycle greenhouse gas releases for several personal vehicle energy supply systems are then estimated. Very substantial reductions of greenhouse gas emissions are possible due to efficiency improvements and changing to less carbon intensive fuels such as natural gas. C02 emissions from on board natural gas fueled versions of hybrid electric cars would be decreased to approximately 25 million t/year from the current 91 million tonnes/year. The ultimate reduction identified is through the use of hydrogen fuel produced via electricity from CANDU power

  6. 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

  7. Exergoeconomic analysis and multi objective optimization of performance of a Carbon dioxide power cycle driven by geothermal energy with liquefied natural gas as its heat sink

    International Nuclear Information System (INIS)

    Ahmadi, Mohammad H.; Mehrpooya, Mehdi; Pourfayaz, Fathollah

    2016-01-01

    Highlights: • A small scale transcritical Carbon dioxide cycle is investigated. • Exergoeconomic analysis of a CO_2 power cycle driven by geothermal energy with LNG as its heat sink. • Three decision-making methods are employed to select final answers. - Abstract: In this study a transcritical Carbon dioxide power cycle has been coupled to a liquefied natural gas to work either as the cold source and to further enhance to generate electricity. The detailed thermodynamic analysis is performed in order to investigate the effect of key parameters on the cycle performance. Also, heat exchangers are measured to find the heat transfer surface area for economic evaluation. To investigate the aforementioned cycle and for optimization purposes, an exergoeconomic analysis is done to know the important components with respect to exergoeconomic criterion. The exergoeconomic analysis reveals that Carbon dioxide turbine and condenser have the highest rate of sum cost rate associated with capital investment and the cost of exergy destruction and special attention should be paid to these components. The parametric analysis shows that there is an optimum turbine inlet pressure which brings about the highest exergy efficiency and lowest product cost rate. Moreover, the condensate pressure has the highest effect on system exergy efficiency compared to others. With the help of multi-objective optimization, the cumulative effects of these variables are investigated on the system to maximize the exergetic efficiency and to minimize the product cost rate of the system. Results show that the system is capable of producing power with exergy efficiency and product cost rate equal to 20.5% and 263592.15 $/year, respectively, according to technique for order of preference by similarity to ideal solution decision making technique. Also, the system exergy efficiency of 22.1% and 295001.26 $/year product cost rate is achieved through linear programming techniques for multidimensional

  8. Numerical model for thermoeconomic diagnosis in commercial transcritical/subcritical booster refrigeration systems

    International Nuclear Information System (INIS)

    Ommen, Torben; Elmegaard, Brian

    2012-01-01

    Highlights: ► A transcritical booster refrigeration plant is modelled. ► We examine changes in cost flow at different operation parameters. ► The use of characteristic curves for diagnosis is studied. - Abstract: Transcritical/subcritical booster refrigeration systems are increasingly installed and used in Danish supermarkets. The systems operate in both transcritical and subcritical conditions dependent on the heat rejection performance and the ambient conditions. The plant consists of one refrigerant cycle supplying refrigerant for evaporators in both chilled and frozen display cases. In the paper, thermoeconomic theory is used to establish the cost of cooling at each individual temperature level based on operating costs. With a high amount of operating systems, faulty operation becomes an economic, and environmental, interest. A general solution for evaluation of these systems is considered, with the objective to reduce cost and power consumption of malfunctioning equipment in operation. An analysis of the use of thermoeconomic diagnosis methods is required, as these methods may prove applicable. To accommodate the analysis, a numerical model of a transcritical booster refrigeration plant is considered in this paper. Additionally the characteristic curves method is applied to the high pressure compressor unit of the refrigeration plant. The approach successfully determine whether an anomaly is intrinsic or induced in the component when no uncertainties are introduced in the steady state model.

  9. Thermodynamic analysis of a novel ejector expansion transcritical CO_2/N_2O cascade refrigeration (NEETCR) system for cooling applications at low temperatures

    International Nuclear Information System (INIS)

    Megdouli, K.; Ejemni, N.; Nahdi, E.; Mhimid, A.; Kairouani, L.

    2017-01-01

    Natural substances are becoming very promising for long term alternative for refrigeration purposes. In this paper, two natural refrigerants have been proposed and analyzed for a novel ejector expansion transcritical cascade refrigeration (NEETCR) system. Nitrous oxide (N_2O) is used in the low temperature circuit (LTC) whereas carbon dioxide (CO_2) is used in the high temperature circuit (HTC) of the NEETCR system. The reject of refrigerant vapor heat in the HTC is carried out through the use of transcritical carbon dioxide Rankine cycle. This produces work, which will be used to reduce the consumption work of compressors and feed pump thereby resulting in the improvement of the energy efficiency of the whole system. The simulation results were obtained by a computer FORTRAN program, where REFPROP 9 database was used to get the refrigerant thermodynamic properties. The simulation results showed that the (NEETCR) system had higher coefficient of performance and higher system second law efficiency compared to the EETCR system. An enhancement more than 9% in the COP and exergy efficiency of NEETCR system was found in comparison with EETCR system, when the cooling capacity and operating conditions of the two systems were the same. The increase of COP of NEETCR system and its efficiency along with the reduction of power consumption make it more practical for the use in cooling applications. - Highlights: • Exergy-energy analysis of two cascade refrigeration systems is conducted. • The input power of the NEETCR system is lower than that of the EETCR system. • The COP of the NEETCR system is higher than that of the EETCR system. • The NEETCR system is promise in cascade refrigeration system.

  10. Power generation from low-temperature heat source

    Energy Technology Data Exchange (ETDEWEB)

    Lakew, Amlaku Abie

    2012-07-01

    The potential of low-temperature heat sources for power production has been discussed for decades. The diversity and availability of low-temperature heat sources makes it interesting for power production. The thermodynamic power cycle is one of the promising technologies to produce electricity from low-temperature heat sources. There are different working fluids to be used in a thermodynamic power cycle. Working fluid selection is essential for the performance of the power cycle. Over the last years, different working fluid screening criteria have been used. In broad speaking the screening criteria can be grouped as thermodynamic performance, component size requirement, economic performance, safety and environmental impact. Screening of working fluids at different heat source temperatures (80-200 Celsius degrees) using thermodynamic performance (power output and exergy efficiency) and component size (heat exchanger and turbine) is investigated. It is found that the 'best' working fluid depends on the criteria used and heat source temperature level. Transcritical power cycles using carbon dioxide as a working fluid is studied to produce power at 100 Celsius degrees. Carbon dioxide is an environmentally friendly refrigerant. The global warming potential of carbon dioxide is 1. Furthermore, because of its low critical temperature (31 Celsius degrees), carbon dioxide can operate in a transcritical power cycle for lower heat source temperatures. A transcritical configuration avoids the problem of pinching which otherwise would happened in subcritical power cycle. In the process, better temperature matching is achieved and more heat is extracted. Thermodynamic analysis of transcritical cycle is performed; it is found that there is an optimal operating pressure for highest net power output. The pump work is a sizable fraction of the work produced by the turbine. The effect of efficiency deterioration of the pump and the turbine is compared. When the

  11. Integrated biofuel facility, with carbon dioxide consumption and power generation

    Energy Technology Data Exchange (ETDEWEB)

    Powell, E.E.; Hill, G.A. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Chemical Engineering

    2009-07-01

    This presentation provided details of an economical design for a large-scale integrated biofuel facility for coupled production of bioethanol and biodiesel, with carbon dioxide capture and power generation. Several designs were suggested for both batch and continuous culture operations, taking into account all costs and revenues associated with the complete plant integration. The microalgae species Chlorella vulgaris was cultivated in a novel photobioreactor (PBR) in order to consume industrial carbon dioxide (CO{sub 2}). This photosynthetic culture can also act as a biocathode in a microbial fuel cell (MFC), which when coupled to a typical yeast anodic half cell, results in a complete biological MFC. The photosynthetic MFC produces electricity as well as valuable biomass and by-products. The use of this novel photosynthetic microalgae cathodic half cell in an integrated biofuel facility was discussed. A series of novel PBRs for continuous operation can be integrated into a large-scale bioethanol facility, where the PBRs serve as cathodic half cells and are coupled to the existing yeast fermentation tanks which act as anodic half cells. These coupled MFCs generate electricity for use within the biofuel facility. The microalgae growth provides oil for biodiesel production, in addition to the bioethanol from the yeast fermentation. The photosynthetic cultivation in the cathodic PBR also requires carbon dioxide, resulting in consumption of carbon dioxide from bioethanol production. The paper also discussed the effect of plant design on net present worth and internal rate of return. tabs., figs.

  12. Discretizing the transcritical and pitchfork bifurcations – conjugacy results

    KAUST Repository

    Ló czi, Lajos

    2015-01-01

    © 2015 Taylor & Francis. We present two case studies in one-dimensional dynamics concerning the discretization of transcritical (TC) and pitchfork (PF) bifurcations. In the vicinity of a TC or PF bifurcation point and under some natural assumptions

  13. Numerical optimization of a transcritical CO2/propylene cascaded ...

    Indian Academy of Sciences (India)

    transcritical CO2/propylene cascade system with parallel compression ... specific volumes, low solidification temperature, low operating pressure of the ...... Kim M, Pettersen J and Bullard C W 2004 Fundamental process and system design ...

  14. Thermoeconomic model of a commercial transcritical booster refrigeration system

    DEFF Research Database (Denmark)

    Ommen, Torben Schmidt; Elmegaard, Brian

    2011-01-01

    For cooling applications in supermarkets, booster refrigeration systems operating in both transcritical and subcritical conditions are increasingly used. A thermodynamic model of a transcritical booster refrigeration plant is tailored to match the new generation of commercial refrigeration plants...... of exergy for cooling. Second law analysis is needed to illustrate the characteristics of the plant at different load rates, according to the alternating load profile and corresponding to outdoor conditions. With the detailed model, different uses of the analysis are possible, including thermoeconomic...

  15. Structure of wall-bounded flows at transcritical conditions

    Science.gov (United States)

    Ma, Peter C.; Yang, Xiang I. A.; Ihme, Matthias

    2018-03-01

    At transcritical conditions, the transition of a fluid from a liquidlike state to a gaslike state occurs continuously, which is associated with significant changes in fluid properties. Therefore, boiling in its conventional sense does not exist and the phase transition at transcritical conditions is known as "pseudoboiling." In this work, direct numerical simulations (DNS) of a channel flow at transcritical conditions are conducted in which the bottom and top walls are kept at temperatures below and above the pseudoboiling temperature, respectively. Over this temperature range, the density changes by a factor of 18 between both walls. Using the DNS data, the usefulness of the semilocal scaling and the Townsend attached-eddy hypothesis are examined in the context of flows at transcritical conditions—both models have received much empirical support from previous studies. It is found that while the semilocal scaling works reasonably well near the bottom cooled wall, where the fluid density changes only moderately, the same scaling has only limited success near the top wall. In addition, it is shown that the streamwise velocity structure function follows a logarithmic scaling and the streamwise energy spectrum exhibits an inverse wave-number scaling, thus providing support to the attached-eddy model at transcritical conditions.

  16. Energy Optimization for Transcritical CO2 Heat Pump for Combined Heating and Cooling and Thermal Storage Applications

    DEFF Research Database (Denmark)

    Do Carmo, Carolina Madeira Ramos; Blarke, Morten; Yazawa, Kazuaki

    2012-01-01

    A transcritical heat pump (THP) cycle using carbon dioxide (CO2) as the refrigerant is known to feature an excellent coefficient of performance (COP) as a thermodynamic system. Using this feature, we are designing and building a system that combines a water-to-water CO2 heat pump with both hot....... The usability and the cost effectiveness are critical for smart grid policies on large-scale integration of intermittent renewables. In this paper, we present an analytic thermodynamic model that predicts the effect of temperature and flow rate of hot and cold water circulation on system COP. The analytical...

  17. Low-Mach number simulations of transcritical flows

    KAUST Repository

    Lapenna, Pasquale E.

    2018-01-08

    A numerical framework for the direct simulation, in the low-Mach number limit, of reacting and non-reacting transcritical flows is presented. The key feature are an efficient and detailed representation of the real fluid properties and an high-order spatial discretization. The latter is of fundamental importance to correctly resolve the largely non-linear behavior of the fluid in the proximity of the pseudo-boiling. The validity of the low-Mach number assumptions is assessed for a previously developed non-reacting DNS database of transcritical and supercritical mixing. Fully resolved DNS data employing high-fidelity thermodynamical models are also used to investigate the spectral characteristic as well as the differences between transcritical and supercritical jets.

  18. 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.

  19. Optimal operating conditions of a transcritical endoreversible cycle using a low enthalpy heat source

    International Nuclear Information System (INIS)

    Rachedi, Malika; Feidt, Michel; Amirat, Madjid; Merzouk, Mustapha

    2016-01-01

    Highlights: • Thermodynamics analysis of a finite size heat engine driven by a finite heat source. • Mathematical modelling of a transcritical endoreversible organic Rankine cycle. • Parametric study of the optimum operating conditions of transcritical cycle. • Choice of appropriate parameters could lead to very promising efficiencies. - Abstract: In the context of thermodynamic analysis of finite dimensions systems, we studied the optimum operating conditions of an endoreversible thermal machine. In this study, we considered a transcritical cycle, considering external irreversibilities. The hot reservoir is a low enthalpy geothermal heat source; therefore, it is assumed to be finite, whereas the cold reservoir is assumed to be infinite. The power optimisation is investigated by searching the optimum effectiveness of the heat-exchanger at the hot side of the engine. The sum of the total effectiveness and the second law of thermodynamics are used as constraints for optimisation. The optimal temperatures of the working fluid and optimum performances are evaluated based on the most significant parameters of the system: (1) the ratio of heat capacity rate of the working fluid to the heat capacity rate of the coolant and (2) the ratio of the sink temperature to the temperature of the hot source. The parametric study of the cycle and its approximation by a trilateral cycle enabled us to determine the optimum value of the effectiveness of the heat exchangers and the optimal operating temperatures of the cycle considered. The efficiencies obtained are in the range of 15–25% and was found to exceed the efficiency expected by the Curzon and Ahlborn prevision; meanwhile, the Carnot efficiency remains at a high limit.

  20. Abatement and mitigation of carbon dioxide emissions from power generation

    International Nuclear Information System (INIS)

    Freund, P.; Audus, H.

    1998-01-01

    Current understanding of the world's climate indicates that human-induced changes are occurring and may be sufficient in magnitude to require preventative action, such as limiting atmospheric concentrations of greenhouse gases. The main anthropogenic greenhouse gas is carbon dioxide and its largest source is combustion of fossil fuels for power generation. Many different technologies can be used for reducing emissions, as well as increasing the removal of CO 2 from the atmosphere through enhancement of natural sinks, such as by forestry. Some of these options are available today and could be implemented at relatively little overall cost. For example, improving energy efficiency and switching from high carbon fuels to low carbon fuels, if suitable supplies are available. These can achieve significant reductions in CO 2 emissions. Introduction of renewable sources of energy or nuclear power to displace fossil fuels would achieve deep reductions in emissions if applied widely. However, to avoid disruptive changes, it will also be necessary to find ways of continuing to use fossil fuels but with much less emissions. Capture and storage of CO 2 is a technology which could deliver deep reductions in emissions from fossil fuels. In this paper, methods of removing CO 2 from the flue gas streams of coal and gas-fired power plants are examined, considering both plant as built today as well as possible future variants. Methods of CO 2 storage are also discussed. The results on capture and storage of CO 2 are put into perspective by comparison with studies of the large-scale application of forestry for sequestering atmospheric CO 2 , and also large-scale use of renewable energy sources, in this case growth and harvesting of woody biomass for power generation. Each of these options has different characteristics, providing a range of choices of ways of tackling climate change

  1. Experimental investigation on the influence of EEV opening on the performance of transcritical CO2 refrigeration system

    International Nuclear Information System (INIS)

    Hou, Yu; Ma, Juanli; Liu, Changhai; Cao, Jing; Liu, Xiufang

    2014-01-01

    In order to investigate the influence of electronic expansion valve (EEV) opening on the performance of the transcritical CO 2 refrigeration system, an experimental test rig of the transcritical CO 2 system was built up. The system operation parameters such as temperature, pressure were measured with different EEV opening, when the inlet temperatures of the gas-cooler water and the evaporator water were set to 30 °C and 15 °C, respectively. The effects of EEV opening on the pressure, temperature and the performance of the system were studied in detail. The results demonstrate that the EEV opening has great effects on the discharge pressure of the compressor, gas-cooler outlet pressure, and the discharge temperature of the compressor. The compressor input power decreases with the increasing of EEV opening. The cooling capacity and the coefficient of performance (COP) of the system peaks at the EEV opening of 40% and 60%, respectively. - Highlights: •Influence of EEV opening on transcritical CO 2 system is investigated experimentally. •EEV opening has little effect on evaporating pressure. •EEV opening has great effects on discharge pressure and temperature of compressor. •Cooling capacity peaks at the EEV opening of 40%. •COP peaks at the EEV opening of 60%

  2. Systematic optimization of subcritical and transcritical organic Rankine cycles (ORCs) constrained by technical parameters in multiple applications

    International Nuclear Information System (INIS)

    Maraver, Daniel; Royo, Javier; Lemort, Vincent; Quoilin, Sylvain

    2014-01-01

    Highlights: • ORC optimization for different target applications. • Model developed to allow computation in subcritical and transcritical operation. • Regenerative and non-regenerative cycles evaluated through second law efficiency. • Common working fluids: R134a, R245fa, Solkatherm, n-Pentane, MDM, Toluene. • Thermodynamic and technological approaches lead to optimal design guidelines. - Abstract: The present work is focused on the thermodynamic optimization of organic Rankine cycles (ORCs) for power generation and CHP from different average heat source profiles (waste heat recovery, thermal oil for cogeneration and geothermal). The general goal is to provide optimization guidelines for a wide range of operating conditions, for subcritical and transcritical, regenerative and non-regenerative cycles. A parameter assessment of the main equipment in the cycle (expander, heat exchangers and feed pump) was also carried out. An optimization model of the ORC (available as an electronic annex) is proposed to predict the best cycle performance (subcritical or transcritical), in terms of its exergy efficiency, with different working fluids. The working fluids considered are those most commonly used in commercial ORC units (R134a, R245fa, Solkatherm, n-Pentane, Octamethyltrisiloxane and Toluene). The optimal working fluid and operating conditions from a purely thermodynamic approach are limited by the technological constraints of the expander, the heat exchangers and the feed pump. Hence, a complementary assessment of both approaches is more adequate to obtain some preliminary design guidelines for ORC units

  3. Experimental investigation on predictive models for motive flow calculation through ejectors for transcritical CO2 heat pumps

    Science.gov (United States)

    Boccardi, G.; Lillo, G.; Mastrullo, R.; Mauro, A. W.; Saraceno, L.; Pieve, M.; Trinchieri, R.

    2017-11-01

    Nowadays, air conditioning systems, especially those used in residential and office buildings, contribute largely to the energy consumptions and to the direct and indirect emissions of greenhouse gases. Carbon dioxide (CO2) is an interesting option to replace traditional HFCs in vapor compression systems, due to its environmentally friendly characteristics: zero ODP and extremely low GWP. In the case of heat pumps, the use of ejection systems for the expansion phase can contribute to recovery a fraction of the mechanical energy otherwise dissipated as friction, bringing to significant benefits in terms of performance. Currently, at the laboratory DTE-PCU-SPCT of the research center ENEA (Casaccia) in cooperation with the Industrial Engineering Department of Federico II University of Naples, a project is in progress, in order to evaluate experimentally the effect of several ejectors geometries on the global performance of a CO2 heat pump working with a transcritical cycle. As a part of this project, measurements of the motive flow mass flow rate have been carried out, in transcritical CO2 conditions. The ejector sizing is a crucial point for the balancing of components and the correct operation of the CO2 heat pump and therefore the availability of reliable calculation methods for the motive flowrate would be useful. This paper presents the results obtained by a comparison between the new experimental data and the predictions of some predictive semi-empirical correlations available in the open literature for transcritical CO2 conditions. Their predictions are analyzed as a function of the main physical parameters of the process to assess their reliability compared to the experimental data. Based on these indications and of the available experimental data, a new semi-empirical correlations and a calculation method based on the hypothesis of isentropic and choked two-phase flow are presented.

  4. Electrochemical Membrane for Carbon Dioxide Capture and Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Ghezel-Ayagh, Hossein [FuelCell Energy, Inc., Danbury, CT (United States)

    2017-12-21

    FuelCell Energy, Inc. (FCE), in collaboration with AECOM Corporation (formerly URS Corporation) and Pacific Northwest National Laboratory, has been developing a novel Combined Electric Power and Carbon-dioxide Separation (CEPACS) system. The CEPACS system is based on electrochemical membrane (ECM) technology derived from FCE’s carbonate fuel cell products featuring internal (methane steam) reforming and carrying the trade name of Direct FuelCell®. The unique chemistry of carbonate fuel cells offers an innovative approach for separation of CO2 from existing fossil-fuel power plant exhaust streams (flue gases). The ECM-based CEPACS system has the potential to become a transformational CO2-separation technology by working as two devices in one: it separates the CO2 from the exhaust of other plants such as an existing coal-fired plant and simultaneously produces clean electric power at high efficiency using a supplementary fuel. The development effort was carried out under the U.S. Department of Energy (DOE) cooperative agreement DE-FE0007634. The overall objective of this project was to successfully demonstrate the ability of FCE’s ECM-based CEPACS system technology to separate ≥90% of the CO2 from a simulated Pulverized Coal (PC) power plant flue gas stream and to compress the captured CO2 to a state that can be easily transported for sequestration or beneficial use. In addition, a key objective was to show, through the technical and economic feasibility study and bench scale testing, that the ECM-based CEPACS system is an economical alternative for CO2 capture in PC power plants, and that it meets DOE’s objective related to the incremental cost of electricity (COE) for post-combustion CO2 capture (no more than 35% increase in COE). The project was performed in three budget periods (BP). The specific objective for BP1 was to complete the Preliminary Technical and Economic Feasibility Study

  5. Current status of waste power generation in Japan and its impact on carbon dioxide reduction

    International Nuclear Information System (INIS)

    Takaoka, Masaki; Takeda, Nobuo; Yamagata, Naruo; Masuda, Takahiro

    2010-01-01

    In this research, we discuss current status of waste power generation (WPG) in Japan and various scenarios about the indirect reduction of carbon dioxide by WPG. The numbers of WPG facilities are 291 domestically as of 2006. Power generation capacity achieves 1584 MW and power generation amount is 7179 G Wh/ year. When we consider to reduce the used electricity for operation and office by WPG and emission coefficient of electricity for operation and office is to be 0.555 kg-CO 2 / kWh in default value, then carbon dioxide reduction amount is calculated to 3.9 million tons, which is equivalent to 26.7 % of 14.6 million tons of carbon dioxide emitted by municipal solid waste incinerator (MSWI) in 2005. Using various existing technological options, it finds that the efficiency of power generation will achieve more than 20 % in MSWI with the power generation efficiency of 20% as a feasible assumption, the total power generation amount and the carbon dioxide reduction amount will become 16540 G Wh/ year and 9.18 million tons, respectively. So, it is equivalent to 62.7% of carbon dioxide emitted by MSWI. Also, the ratio of additional reduction amount of carbon dioxide by WPG to total additional reduction amount in Japan during the first commitment period is 26.3%, which suggests that the promotion of WPG in MSWI is one of effective options for prevention of global warming. (author)

  6. High Fidelity Simulation of Transcritical Liquid Jet in Crossflow

    Science.gov (United States)

    Li, Xiaoyi; Soteriou, Marios

    2017-11-01

    Transcritical injection of liquid fuel occurs in many practical applications such as diesel, rocket and gas turbine engines. In these applications, the liquid fuel, with a supercritical pressure and a subcritical temperature, is introduced into an environment where both the pressure and temperature exceeds the critical point of the fuel. The convoluted physics of the transition from subcritical to supercritical conditions poses great challenges for both experimental and numerical investigations. In this work, numerical simulation of a binary system of a subcritical liquid injecting into a supercritical gaseous crossflow is performed. The spatially varying fluid thermodynamic and transport properties are evaluated using established cubic equation of state and extended corresponding state principles with established mixing rules. To efficiently account for the large spatial gradients in property variations, an adaptive mesh refinement technique is employed. The transcritical simulation results are compared with the predictions from the traditional subcritical jet atomization simulations.

  7. Health Risk Assessment of Nitrogen Dioxide and Sulfur Dioxide Exposure from a New Developing Coal Power Plant in Thailand

    Directory of Open Access Journals (Sweden)

    Tin Thongthammachart

    2017-07-01

    Full Text Available Krabi coal-fired power plant is the new power plant development project of the Electricity Generating Authority of Thailand (EGAT. This 800 megawatts power plant is in developing process. The pollutants from coal-fired burning emissions were estimated and included in an environmental impact assessment report. This study aims to apply air quality modeling to predict nitrogen dioxide (NO2 and sulfur dioxide (SO2 concentration which could have health impact to local people. The health risk assessment was studied following U.S. EPA regulatory method. The hazard maps were created by ArcGIS program. The results indicated the influence of the northeast and southwest monsoons and season variation to the pollutants dispersion. The daily average and annual average concentrations of NO2 and SO2 were lower than the NAAQS standard. The hazard quotient (HQ of SO2 and NO2 both short-term and long-term exposure were less than 1. However, there were some possibly potential risk areas indicating in GIS based map. The distribution of pollutions and high HI values were near this power plant site. Although the power plant does not construct yet but the environment health risk assessment was evaluated to compare with future fully developed coal fire plant.

  8. Diffuse interfacelets in transcritical flows of propellants into high-pressure combustors

    Science.gov (United States)

    Urzay, Javier; Jofre, Lluis

    2017-11-01

    Rocket engines and new generations of high-power jet engines and diesel engines oftentimes involve the injection of one or more reactants at subcritical temperatures into combustor environments at high pressures, and more particularly, at pressures higher than those corresponding to the critical points of the individual components of the mixture, which typically range from 13 to 50 bars for most propellants. This class of trajectories in the thermodynamic space has been traditionally referred to as transcritical. Under particular conditions often found in hydrocarbon-fueled chemical propulsion systems, and despite the prevailing high pressures, the flow in the combustor may contain regions close to the injector where a diffuse interface is formed in between the fuel and oxidizer streams that is sustained by surface-tension forces as a result of the elevation of the critical pressure of the mixture. This talk describes progress towards modeling these effects in the conservation equations. Funded by the US Department of Energy.

  9. 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)

  10. Discretizing the transcritical and pitchfork bifurcations – conjugacy results

    KAUST Repository

    Lóczi, Lajos

    2015-01-07

    © 2015 Taylor & Francis. We present two case studies in one-dimensional dynamics concerning the discretization of transcritical (TC) and pitchfork (PF) bifurcations. In the vicinity of a TC or PF bifurcation point and under some natural assumptions on the one-step discretization method of order (Formula presented.) , we show that the time- (Formula presented.) exact and the step-size- (Formula presented.) discretized dynamics are topologically equivalent by constructing a two-parameter family of conjugacies in each case. As a main result, we prove that the constructed conjugacy maps are (Formula presented.) -close to the identity and these estimates are optimal.

  11. Combustion systems and power plants incorporating parallel carbon dioxide capture and sweep-based membrane separation units to remove carbon dioxide from combustion gases

    Science.gov (United States)

    Wijmans, Johannes G [Menlo Park, CA; Merkel, Timothy C [Menlo Park, CA; Baker, Richard W [Palo Alto, CA

    2011-10-11

    Disclosed herein are combustion systems and power plants that incorporate sweep-based membrane separation units to remove carbon dioxide from combustion gases. In its most basic embodiment, the invention is a combustion system that includes three discrete units: a combustion unit, a carbon dioxide capture unit, and a sweep-based membrane separation unit. In a preferred embodiment, the invention is a power plant including a combustion unit, a power generation system, a carbon dioxide capture unit, and a sweep-based membrane separation unit. In both of these embodiments, the carbon dioxide capture unit and the sweep-based membrane separation unit are configured to be operated in parallel, by which we mean that each unit is adapted to receive exhaust gases from the combustion unit without such gases first passing through the other unit.

  12. Value of forestation in absorbing carbon dioxide surrounding a coal fired power plant

    Energy Technology Data Exchange (ETDEWEB)

    Dang, V.D.; Steinberg, M.

    1980-08-01

    The dispersion of carbon dioxide emitted from 1000 MW(e) coal fired power plant is investigated. Calculated ground level carbon dioxide concentrations as a function of distance from the power plant stack is validated by the results derived from sulfur dioxide dispersion measurements. Forestation is examined as a means for removal and control of atmospheric carbon dioxide at a distance of 5 to 10 km away from the power plant stack. An equilibrium and a dynamic approach are considered. For an average temperate zone forest growth rate (7.42 mg/dm/sup 2/ h), the overall reduction in forested land area required to remove the equivalent of all of the CO/sub 2/ from a 1000 MW(e) power plant would be less than 3.3% compared to removing the equivalent amount of CO/sub 2/ by planting forests remotely from the plant. If faster growing tropical plants or trees having up to 4 times the temperate plant growth rate were used, there would be a maximum savings of 15% in forested land area compared to a remote planting. This magnitude of reduction in cultivated forest area is insufficient to recommend planting forested areas adjacent to central power stations as a means of controlling CO/sub 2/ emission. Rather it is suggested to provide sufficient increased regional forested areas on a global scale for the purposes of absorbing the equivalent increase in CO/sub 2/ emission due to increased fossil fuel use.

  13. Simulation of Transcritical CO2 Refrigeration System with Booster Hot Gas Bypass in Tropical Climate

    Science.gov (United States)

    Santosa, I. D. M. C.; Sudirman; Waisnawa, IGNS; Sunu, PW; Temaja, IW

    2018-01-01

    A Simulation computer becomes significant important for performance analysis since there is high cost and time allocation to build an experimental rig, especially for CO2 refrigeration system. Besides, to modify the rig also need additional cos and time. One of computer program simulation that is very eligible to refrigeration system is Engineering Equation System (EES). In term of CO2 refrigeration system, environmental issues becomes priority on the refrigeration system development since the Carbon dioxide (CO2) is natural and clean refrigerant. This study aims is to analysis the EES simulation effectiveness to perform CO2 transcritical refrigeration system with booster hot gas bypass in high outdoor temperature. The research was carried out by theoretical study and numerical analysis of the refrigeration system using the EES program. Data input and simulation validation were obtained from experimental and secondary data. The result showed that the coefficient of performance (COP) decreased gradually with the outdoor temperature variation increasing. The results show the program can calculate the performance of the refrigeration system with quick running time and accurate. So, it will be significant important for the preliminary reference to improve the CO2 refrigeration system design for the hot climate temperature.

  14. 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.

  15. Data for comparison of chlorine dioxide and chlorine disinfection power in a real dairy wastewater effluent

    Directory of Open Access Journals (Sweden)

    Maliheh Akhlaghi

    2018-06-01

    Full Text Available Disinfection of water refers to a special operation that is doing to kill or disable causative organisms (i.e. Pathogens and in particular, intestinal bacteria. The aim of this pilot study is comparison of disinfection power of Chlorine dioxide and chlorine in a real dairy wastewater effluent. In this regard, firstly prepared two 220-l tanks made of polyethylene as reaction tanks and filled by effluent of a dairy wastewater treatment plant. Both tanks were equipped with mechanical stirrer. Then a Diaphragm dosing pumps with the maximum capacity of 3.9 l per hour were used for the chlorine dioxide and chlorine (Calcium hypochlorite 0.5 up to 3 ppm injection. Residual level of Chlorine dioxide and Chlorine were measured by portable photometric method DT4B kit, Germany. Finally, the Multiple-Tube Fermentation, Brilliant Green Bile Broth (BGB and Eosin methylene blue Agar (EMB technique was used for microbial analysis and the results were reported as the most probable number index (MPN respectively. The data showed that the residual of chlorine dioxide could stood more active than residual of chlorine in the aqueous environment significantly. Therefore, Use of chlorine dioxide is more effective than chlorine for removal fecal and total coliform from dairy wastewater effluent. Keywords: Disinfection, Chlorine dioxide, Chlorine, Total coliform, Fecal coliform

  16. COHO - Utilizing Waste Heat and Carbon Dioxide at Power Plants for Water Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Sumanjeet [Porifera Inc., Hayward, CA (United States); Wilson, Aaron [Porifera Inc., Hayward, CA (United States); Wendt, Daniel [Porifera Inc., Hayward, CA (United States); Mendelssohn, Jeffrey [Porifera Inc., Hayward, CA (United States); Bakajin, Olgica [Porifera Inc., Hayward, CA (United States); Desormeaux, Erik [Porifera Inc., Hayward, CA (United States); Klare, Jennifer [Porifera Inc., Hayward, CA (United States)

    2017-07-25

    The COHO is a breakthrough water purification system that can concentrate challenging feed waters using carbon dioxide and low-grade heat. For this project, we studied feeds in a lab-scale system to simulate COHO’s potential to operate at coal- powered power plants. COHO proved successful at concentrating the highly scaling and challenging wastewaters derived from a power plant’s cooling towers and flue gas desulfurization units. We also found that COHO was successful at scrubbing carbon dioxide from flue gas mixtures. Thermal regeneration of the switchable polarity solvent forward osmosis draw solution ended up requiring higher temperatures than initially anticipated, but we also found that the draw solution could be polished via reverse osmosis. A techno-economic analysis indicates that installation of a COHO at a power plant for wastewater treatment would result in significant savings.

  17. Carbon dioxide recovery from gas-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Ricardo Salgado; Barbosa, Joao Roberto [Centro Tecnico Aeroespacial, Sao Jose dos Campos, SP (Brazil). Inst. Tecnologico de Aeronautica. Dept. de Energia]. E-mails: martinsr@epenergy.com; barbosa@mec.ita.br; Prado, Eduardo Lanari [Rice Univ., Houston, TX (United States). Jones Graduate School of Business]. E-mail: pradoe@epenergy.com; Vieira, Adriana de Moura [Instituto Brasileiro de Mercado de Capitais (IBMEC), Rio de Janeiro, RJ (Brazil). Dept. de Financas]. E-mail: vieiraa@epenergy.com

    2000-07-01

    Since 1996 the Brazilian electric sector has undergone a major restructuring. The aim of such change is to reduce the State's participation in the sector, and to induce the growth of private investments. In particular, this event created several opportunities for thermal power plant projects, leading to competition at the generation level. In this scenario of increased competition, the power plant efficiency becomes a key element for determining the feasibility and profitability of the project. Moreover, the utilization of the plant's own effluents as feedstock or as a source of additional revenue will impact positively in its economics. As an example, long term additional revenues could be created by the sale of CO{sub 2} extracted from the combustion products of thermal power plants. The production of CO{sub 2} also contributes to mitigate the environmental impacts of the power plant project by significantly reducing its airborne emissions. This paper shows how a gas-fired power plant can extract and utilize CO{sub 2} to generate additional revenue, contributing to a more competitive power plant. (author)

  18. Integration between direct steam generation in linear solar collectors and supercritical carbon dioxide Brayton power cycles

    OpenAIRE

    Coco Enríquez, Luis; Muñoz Antón, Javier; Martínez-Val Peñalosa, José María

    2015-01-01

    Direct Steam Generation in Parabolic Troughs or Linear Fresnel solar collectors is a technology under development since beginning of nineties (1990's) for replacing thermal oils and molten salts as heat transfer fluids in concentrated solar power plants, avoiding environmental impacts. In parallel to the direct steam generation technology development, supercritical Carbon Dioxide Brayton power cycles are maturing as an alternative to traditional Rankine cycles for increasing net plant efficie...

  19. Climate Adaptivity and Field Test of the Space Heating Used Air-Source Transcritical CO2 Heat Pump

    Science.gov (United States)

    Song, Yulong; Ye, Zuliang; Cao, Feng

    2017-08-01

    In this study, an innovation of air-sourced transcritical CO2 heat pump which was employed in the space heating application was presented and discussed in order to solve the problem that the heating performances of the transcritical CO2 heat pump water heater deteriorated sharply with the augment in water feed temperature. An R134a cycle was adopted as a subcooling device in the proposed system. The prototype of the presented system was installed and supplied hot water for three places in northern China in winter. The field test results showed that the acceptable return water temperature can be increased up to 55°C, while the supply water temperature was raised rapidly by the presented prototype to up to 70°C directly, which was obviously appropriate to the various conditions of heating radiator in space heating application. Additionally, though the heating capacity and power dissipation decreased with the decline in ambient temperature or the augment in water temperature, the presented heat pump system performed efficiently whatever the climate and water feed temperature were. The real time COP of the presented system was generally more than 1.8 in the whole heating season, while the seasonal performance coefficient (SPC) was also appreciable, which signified that the economic efficiency of the presented system was more excellent than other space heating approaches such as fuel, gas, coal or electric boiler. As a result, the novel system will be a promising project to solve the energy issues in future space heating application.

  20. Coal and carbon dioxide reduction: What does it mean for our power production future?

    International Nuclear Information System (INIS)

    Weinstein, R.E.

    1994-01-01

    Carbon dioxide (CO 2 ) is not a pollutant. It is a limiting nutrient, like water and oxygen, necessary for life to exist on earth. It helps retain heat from the sun keeping the earth comfortably warm. Though scientifically controversial, some segments of the public are nonetheless concerned that increasing amounts of carbon dioxide (and other gases) emitted by mankind's activity may contribute to what they perceive as mankind-induced global warming trend, the so-called open-quotes greenhouse effect.close quotes The 1992 Earth Summit in Rio De Janeiro addressed this, and in response, the U.S. signed agreements to roll back its greenhouse gas emissions to 1990 levels. Carbon dioxide is of concern as a greenhouse gas because of the quantity produced by the combustion of fossil fuels. Because coal is mostly carbon, when burned, it produces more carbon dioxide per Btu of energy released of any of the common fossil fuels. With 54 percent of our electricity generated by coal, capping carbon dioxide emissions without disrupting the economy will be no mean feat for the United States. The U.S. also relies on its huge reserves for its energy independence, so altering policies that affect coal use must be carefully assessed. A growing population and economy demand more energy. One can use other fuels than coal: natural gas releases only 56 percent the carbon dioxide coal does, and nuclear energy produces none. One can also employ higher efficiency coal plants to reduce the amount of carbon dioxide produced for a given power output. The highest efficiency coal units projected are magnetohydrodynamics (MHD) plants the focus of this conference which are projected to produce electricity at 60 percent energy efficiency, extraordinary by today's standards. Does this mean that the Rio de Janeiro agreement then encourages the earlier introduction of MHD and other emerging high efficiency coal technologies?

  1. Nuclear power and carbon dioxide; The fallacy of the nuclear industry's new propaganda

    Energy Technology Data Exchange (ETDEWEB)

    Mortimer, N. (Sheffield City Polytechnic (UK). School of Urban and Regional Studies)

    The increasingly beleaguered nuclear industry is now highlighting the threat of global warming as a justification for its continued expansion. The industry argues that it produces no carbon dioxide and that nuclear power is therefore a key element in any plan to reduce emissions of this greenhouse gas. However an analysis of the entire nuclear fuel cycle shows that nuclear power is responsible for much larger carbon dioxide emissions than several renewable energy options and efficiency measures. Furthermore, a major expansion of nuclear generating capacity would result in huge increases in CO{sub 2} emissions from the nuclear industry due to the need to mine and process progressively lower quality uranium ores. Nuclear power is an expensive, unsustainable, dangerous and ineffective option in any realistic strategy to combat global warming. (Author).

  2. DNS of transcritical turbulent boundary layers at supercritical pressures under abrupt variations in thermodynamic properties

    Science.gov (United States)

    Kawai, Soshi

    2014-11-01

    In this talk, we first propose a numerical strategy that is robust and high-order accurate for enabling to simulate transcritical flows at supercritical pressures under abrupt variations in thermodynamic properties due to the real fluid effects. The method is based on introducing artificial density diffusion in a physically-consistent manner in order to capture the steep variation of thermodynamic properties in transcritical conditions robustly, while solving a pressure evolution equation to achieve pressure equilibrium at the transcritical interfaces. We then discuss the direct numerical simulation (DNS) of transcritical heated turbulent boundary layers on a zero-pressure-gradient flat plate at supercritical pressures. To the best of my knowledge, the present DNS is the first DNS of zero-pressure-gradient flat-plate transcritical turbulent boundary layer. The turbulent kinetic budget indicates that the compressibility effects (especially, pressure-dilatation correlation) are not negligible at the transcritical conditions even if the flow is subsonic. The unique and interesting interactions between the real fluid effects and wall turbulence, and their turbulence statistics, which have never been seen in the ideal-fluid turbulent boundary layers, are also discussed. This work was supported in part by Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Young Scientists (A) KAKENHI 26709066 and the JAXA International Top Young Fellowship Program.

  3. Large scale carbon dioxide production from coal-fired power stations for enhanced oil recovery: a new economic feasibility study

    International Nuclear Information System (INIS)

    Tontiwachwuthikul, P.; Chan, C. W.; Kritpiphat, W.; Demontigny, D.; Skoropad, D.; Gelowitz, D.; Aroonwilas, A.; Mourits, F.; Wilson, M.; Ward, L.

    1998-01-01

    The concept of capturing carbon dioxide from fossil-fuelled electric power generating plants and utilizing it as a flooding agent in enhanced oil recovery (EOR) processes, was explored. In this context, this paper describes how cogeneration concepts, together with process optimization strategies, help to reduce the carbon dioxide production cost by utilizing low-pressure steam and waste heat from various sections of the power generation process. Based on these optimization strategies, the recovery cost of carbon dioxide from coal-fired power stations is estimated to be in the range of $ 0.50 to $ 2.00/mscf. Assuming an average cost of $ 1.25/mscf, the production cost of incremental oil would be about $ 18.00. This means that even with today's modest oil prices, there is room for profit to be made operating a carbon dioxide flood with flue gas extracted carbon dioxide

  4. Sulfur dioxide concentrations near thermoelectric power plant of Rossano Calabro (Italy)

    International Nuclear Information System (INIS)

    Florio, G.

    1991-01-01

    This article presents the results of a one-year atmospheric sulfur dioxide concentration monitoring campaign conducted with the use of five detection stations situated near the 320 MW thermoelectric power plant serving the coastal town of Rossano Calabro (population 50,000). Apart from the analysis of sulfur dioxide concentrations, a meteorological study was carried out based on anemological data. Comparisons were made with reference to the relevant legal standards. It was thus possible to ascertain that air quality near the power station is quite high. Nevertheless, it should be pointed out that, due to the particular local meteorological situation strongly turbulent sea breezes, new detection stations should be opened in this area which may undergo significant industrial development

  5. Sulfur dioxide concentrations near thermoelectric power plant of Rossano Calabro (Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Florio, G. (Calabria Univ., Arcavacata di Rende (Italy). Dipt. di Meccanica)

    This article presents the results of a one-year atmospheric sulfur dioxide concentration monitoring campaign conducted with the use of five detection stations situated near the 320 MW thermoelectric power plant serving the coastal town of Rossano Calabro (population 50,000). Apart from the analysis of sulfur dioxide concentrations, a meteorological study was carried out based on anemological data. Comparisons were made with reference to the relevant legal standards. It was thus possible to ascertain that air quality near the power station is quite high. Nevertheless, it should be pointed out that, due to the particular local meteorological situation strongly turbulent sea breezes, new detection stations should be opened in this area which may undergo significant industrial development.

  6. The role of accelerated power generation technology development to carbon dioxide emissions

    International Nuclear Information System (INIS)

    Russ, P.

    2004-01-01

    The paper focuses on the role of advanced power generation technology in the reduction of carbon dioxide emissions. In order to quantify the importance of these technologies a scenario approach is applied comparing a 'business as usual' scenario with technology cases which assume the accelerated development and earlier availability of certain advanced technologies. The simulations with the POLES world energy model demonstrate that the availability of advanced technology for power generation alone does not lead to emission reductions needed to stabilise carbon dioxide emissions in the atmosphere at a sustainable level. To achieve that additional policy measures are necessary. It is however shown, that the availability of advanced technology has a crucial impact on the cost to meet emission reduction targets. (Author)

  7. Thermodynamic performance analysis of a coupled transcritical and subcritical organic Rankine cycle system for waste heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Xi Wu [Zhejiang Ocean University, Zhejian (China); Wang, Xiao Qiong; Li, You Rong; Wu, Chun Mei [Chongqing University, Chongqing (China)

    2015-07-15

    We present a novel coupled organic Rankine cycle (CORC) system driven by the low-grade waste heat, which couples a transcritical organic Rankine cycle with a subcritical organic Rankine cycle. Based on classical thermodynamic theory, a detailed performance analysis on the novel CORC system was performed. The results show that the pressure ratio of the expander is decreased in the CORC and the selection of the working fluids becomes more flexible and abundant. With the increase of the pinch point temperature difference of the internal heat exchanger, the net power output and thermal efficiency of the CORC all decrease. With the increase of the critical temperature of the working fluid, the system performance of the CORC is improved. The net power output and thermal efficiency of the CORC with isentropic working fluids are higher than those with dry working fluids.

  8. 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

  9. Theoretical research on working fluid selection for a high-temperature regenerative transcritical dual-loop engine organic Rankine cycle

    International Nuclear Information System (INIS)

    Tian, Hua; Liu, Lina; Shu, Gequn; Wei, Haiqiao; Liang, Xingyu

    2014-01-01

    Highlights: • Among all examined working fluids, toluene possesses the maximum W net , highest η e and η ec . • The increase of T 3 worsens system performance, decreasing W net , η e and η ec . • Condenser C LT and turbine T LT possesses the least system irreversibility. • Turbines and exhaust evaporators are optimization components. - Abstract: In this paper, a regenerative transcritical dual-loop organic Rankine cycle is proposed to recover the waste heat of the exhaust, engine coolant and all the residual heat of the HT loop. Double regenerators are adopted in this system. Transcritical cycles are used in both loops. Hexamethyldisiloxane (MM), octamethyl cyclotetrasiloxane (D 4 ), octamethyltrisiloxane (MDM), cyclohexane, toluene and n-decane are chosen as the candidate working fluids of the HT loop and R143a is chosen as the working fluid of the LT loop. Influences of inlet temperature of turbine T HT (T 3 ) on mass flow rates (m f,HT and m f,LT ), net output power (W net ), energy conversion efficiency (η ec ), volumetric expansion ratio (VER), ratio of power consumed to power output (COR) and component irreversibility are analyzed and performance comparison of these working fluids is also evaluated. Results show that toluene possesses the maximum W net (42.46 kW), highest η e (51.92%) and η ec (12.77%). The increase of T 3 worsens system performance, decreasing W net , η e and η ec . Condenser C LT and turbine T LT possess the least system irreversibility. In addition, turbines and exhaust evaporators are optimized components

  10. Possibilities for Carbon Dioxide Emission Reduction Resulting from Nuclear Power Use

    International Nuclear Information System (INIS)

    Bozicevic, M.; Tomsic, Z.; Kovacevic, T.

    1998-01-01

    Each energy resource is connected to certain environmental impacts and risks which must be taken into account. In recent years attention has been focused on the climate change effects of the burning fossil fuels, especially coal, due to the carbon dioxide which this releases into the atmosphere. If the electric energy produced in nuclear power plants were produced in coal-fired plants, global CO 2 emissions would rise for more than 2000 million tons, a significant value in comparison with 4000 million tons which is recommended as a target for emission reduction by the year 2005 at the Toronto Conference on the Changing Atmosphere. Possibilities for carbon dioxide emission reduction which would be the result of the nuclear option acceptance are discussed in this paper. (author)

  11. First results of transcritical magnetized collisionless shock studies on MSX

    Science.gov (United States)

    Weber, T. E.; Smith, R. J.; Hutchinson, T. M.; Taylor, S. F.; Hsu, S. C.

    2014-10-01

    Magnetized collisionless shocks exhibit transitional length and time scales much shorter than can be created through collisional processes. They are common throughout the cosmos, but have historically proven difficult to create in the laboratory. The Magnetized Shock Experiment (MSX) at LANL produces super-Alfvénic shocks through the acceleration and subsequent stagnation of Field Reversed Configuration (FRC) plasmoids against a strong magnetic mirror and flux-conserving vacuum boundary. Plasma flows have been produced with sonic and Alfvén Mach numbers up to ~10 over a wide range of plasma beta with embedded perpendicular, oblique, and parallel magnetic field. Macroscopic ion skin-depth and long ion-gyroperiod enable diagnostic access to relevant shock physics using common methods. Variable plasmoid velocity, density, temperature, and magnetic field provide access to a wide range of shock conditions, and a campaign to study the physics of transcritical and supercritical shocks within the FRC plasmoid is currently underway. An overview of the experimental design, diagnostics suite, physics objectives, and recent results will be presented. Supported by DOE Office of Fusion Energy Sciences under DOE Contract DE-AC52-06NA25369.

  12. Status of thermal power generation in India-Perspectives on capacity, generation and carbon dioxide emissions

    International Nuclear Information System (INIS)

    Ghosh, Subhodip

    2010-01-01

    India's reliance on fossil-fuel based electricity generation has aggravated the problem of high carbon dioxide (CO 2 ) emissions from combustion of fossil fuels, primarily coal, in the country's energy sector. The objective of this paper is to analyze thermal power generation in India for a four-year period and determine the net generation from thermal power stations and the total and specific CO 2 emissions. The installed generating capacity, net generation and CO 2 emissions figures for the plants have been compared and large generators, large emitters, fuel types and also plant vintage have been identified. Specific emissions and dates of commissioning of plants have been taken into account for assessing whether specific plants need to be modernized. The focus is to find out areas and stations which are contributing more to the total emissions from all thermal power generating stations in the country and identify the overall trends that are emerging.

  13. New transcritical CO{sub 2} compressor series; Neue transkritische CO{sub 2}-Verdichterbaureihe

    Energy Technology Data Exchange (ETDEWEB)

    Froeschle, Manuel [GEA Bock GmbH, Frickenhausen (Germany)

    2011-10-15

    The use of natural refrigerants that is recently discussed, is not a new development, but has grown in importance in the last few years. Particularly in the supermarket- and heat pump area, a growing demand in CO{sub 2}-systems for subcritical and transcritical applications could be observed. An extension of the CO{sub 2} components in this area is therefore absolutely necessary. For this reason a completely new transcritical compressor series for maximum pressures of up to 150 bar and extended capacity stages was developed especially. (orig.)

  14. 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

  15. 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)

  16. Isolation and selection of microalgae from coal fired thermoelectric power plant for biofixation of carbon dioxide

    International Nuclear Information System (INIS)

    Morais, Michele Greque de; Costa, Jorge Alberto Vieira

    2007-01-01

    Global warming is thought to be caused mainly by the emission of carbon dioxide (CO 2 ), with thermoelectric power plants being responsible for about 7% of global CO 2 emissions. Microalgae can reduce CO 2 emissions from thermoelectric power plants, but for this use, they must be resistant to the mixture of gases produced by the power plants. We isolated the microalgae Scenedesmus obliquus and Chlorella kessleri from the waste treatment ponds of the Presidente Medici coal fired thermoelectric power plant in the Southernmost Brazilian state of Rio Grande do Sul and investigated their growth characteristics when exposed to different concentrations of CO 2 . When cultivated with 6% and 12% CO 2 , C. kessleri showed a high maximum specific growth rate (μ max ) of 0.267/day, with a maximum biomass productivity (P max ) of 0.087 g/L/day at 6% CO 2 . For S. obliquus, the highest maximum dry weight biomass value was 1.14 g/L with 12% CO 2 . We also found that these two microalgae also grew well when the culture medium contained up to 18% CO 2 , indicating that they have potential for biofixation of CO 2 in thermoelectric power plants

  17. Isolation and selection of microalgae from coal fired thermoelectric power plant for biofixation of carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    de Morais, M.G.; Costa, J.A.V. [Federal University of Rio Grande, Rio Grande (Brazil)

    2007-07-15

    Global warming is thought to be caused mainly by the emission of carbon dioxide (CO{sub 2}), with thermoelectric power plants being responsible for about 7% of global CO{sub 2} emissions. Microalgae can reduce CO{sub 2} emissions from thermoelectric power plants, but for this use, they must be resistant to the mixture of gases produced by the power plants. We isolated the microalgae Scenedesmus obliquus and Chlorella kessleri from the waste treatment ponds of the Presidente Medici coal fired thermoelectric power plant in the Southernmost Brazilian state of Rio Grande do Sul and investigated their growth characteristics when exposed to different concentrations of CO{sub 2}. When cultivated with 6% and 12% CO{sub 2}, C. kessleri showed a high maximum specific growth rate ({lambda}{sub max}) of 0.267/day, with a maximum biomass productivity (P-max) of 0.087 g/L/day at 6% CO{sub 2}. For S. obliquus, the highest maximum dry weight biomass value was 1.14 g/L with 12% CO{sub 2}. We also found that these two microalgae also grew well when the culture medium contained up to 18% CO{sub 2}, indicating that they have potential for biofixation of CO{sub 2} in thermoelectric power plants.

  18. Isolation and selection of microalgae from coal fired thermoelectric power plant for biofixation of carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Michele Greque de [Department of Chemistry, Laboratory of Biochemistry Engineering, Federal University Foundation of Rio Grande, Rio Grande, RS (Brazil); Costa, Jorge Alberto Vieira [Department of Chemistry, Laboratory of Biochemistry Engineering, Federal University Foundation of Rio Grande, Rio Grande, RS (Brazil)]. E-mail: dqmjorge@furg.br

    2007-07-15

    Global warming is thought to be caused mainly by the emission of carbon dioxide (CO{sub 2}), with thermoelectric power plants being responsible for about 7% of global CO{sub 2} emissions. Microalgae can reduce CO{sub 2} emissions from thermoelectric power plants, but for this use, they must be resistant to the mixture of gases produced by the power plants. We isolated the microalgae Scenedesmus obliquus and Chlorella kessleri from the waste treatment ponds of the Presidente Medici coal fired thermoelectric power plant in the Southernmost Brazilian state of Rio Grande do Sul and investigated their growth characteristics when exposed to different concentrations of CO{sub 2}. When cultivated with 6% and 12% CO{sub 2}, C. kessleri showed a high maximum specific growth rate ({mu} {sub max}) of 0.267/day, with a maximum biomass productivity (P {sub max}) of 0.087 g/L/day at 6% CO{sub 2}. For S. obliquus, the highest maximum dry weight biomass value was 1.14 g/L with 12% CO{sub 2}. We also found that these two microalgae also grew well when the culture medium contained up to 18% CO{sub 2}, indicating that they have potential for biofixation of CO{sub 2} in thermoelectric power plants.

  19. Numerical investigation on cryogenic liquid jet under transcritical and supercritical conditions

    Science.gov (United States)

    Li, Liang; Xie, Maozhao; Wei, Wu; Jia, Ming; Liu, Hongsheng

    2018-01-01

    Cryogenic fluid injection and mixing under transcritical and supercritical conditions is numerically investigated with emphasis on the difference of the mechanism and characteristics between the two injections. A new solver is developed which is capable of handling the nonideality of the equation of state and the anomalies in fluid transport properties and is incorporated into the CFD software OpenFOAM. The new solver has been validated against available experimental data and exhibits a good performance. Computational results indicates that the differences between transcritical and supercritical injections are mainly induced by the pseudo-boiling phenomenon, resulting in that the transcritical jet has a longer cold liquid core and an isothermal expansion occurs at the surface of the cold core. The thickness of the supercritical mixing layer and its increase value along the jet direction are greater than its transcritical counterpart. The high-temperature jet whose initial temperature is above the pseudo-boiling temperature has the ability of enhancing the mixing of the jet with the surrounding gas.

  20. Theoretical research on the performance of the transcritical ejector refrigeration cycle with various refrigerants

    International Nuclear Information System (INIS)

    Wang, F.; Li, D.Y.; Zhou, Y.

    2015-01-01

    The transcritical ejector refrigeration cycle (TERC), which has shown an attractive alternative to the ejector refrigeration systems, can better match large variable-temperature heat sources and yields higher COP. In this paper, in order to find a proper working fluid for the TERC, the performance of the TERC with CO_2 and various working fluids with low critical temperatures including R1270, R32, R143a, R125 and R115 are studied and compared. A thermodynamic model for ejector is set up to simulate the ejector by introducing the real properties of refrigerants. The results indicate that R1270 has the highest COP at the same heat source condition and medium working pressures, and is one of environment-friendly working fluids, hence R1270 is the most proper one. The COP of the transcritical cycle is higher than that of the subcritical cycle, and The effective performance coefficient COP_m of the transcritical cycle is also better. When the heater outlet temperature is increased, its system COP_m improves, but its system COP almost does not change. - Highlights: • A thermodynamic model is used to simulate the ejector with real properties. • The performance of the TERC with various refrigerants is compared. • The environment-friendly working fluid of R1270 shows the most proper one. • The COP of the transcritical cycle is higher than that of the subcritical cycle.

  1. Carbon dioxide capture and separation techniques for advanced power generation point sources

    Energy Technology Data Exchange (ETDEWEB)

    Pennline, H.W.; Luebke, D.R.; Morsi, B.I.; Heintz, Y.J.; Jones, K.L.; Ilconich, J.B.

    2006-09-01

    The capture/separation step for carbon dioxide (CO2) from large-point sources is a critical one with respect to the technical feasibility and cost of the overall carbon sequestration scenario. For large-point sources, such as those found in power generation, the carbon dioxide capture techniques being investigated by the in-house research area of the National Energy Technology Laboratory possess the potential for improved efficiency and costs as compared to more conventional technologies. The investigated techniques can have wide applications, but the research has focused on capture/separation of carbon dioxide from flue gas (postcombustion from fossil fuel-fired combustors) and from fuel gas (precombustion, such as integrated gasification combined cycle – IGCC). With respect to fuel gas applications, novel concepts are being developed in wet scrubbing with physical absorption; chemical absorption with solid sorbents; and separation by membranes. In one concept, a wet scrubbing technique is being investigated that uses a physical solvent process to remove CO2 from fuel gas of an IGCC system at elevated temperature and pressure. The need to define an ideal solvent has led to the study of the solubility and mass transfer properties of various solvents. Fabrication techniques and mechanistic studies for hybrid membranes separating CO2 from the fuel gas produced by coal gasification are also being performed. Membranes that consist of CO2-philic silanes incorporated into an alumina support or ionic liquids encapsulated into a polymeric substrate have been investigated for permeability and selectivity. An overview of two novel techniques is presented along with a research progress status of each technology.

  2. Carbon Dioxide Capture and Separation Techniques for Gasification-based Power Generation Point Sources

    Energy Technology Data Exchange (ETDEWEB)

    Pennline, H.W.; Luebke, D.R.; Jones, K.L.; Morsi, B.I. (Univ. of Pittsburgh, PA); Heintz, Y.J. (Univ. of Pittsburgh, PA); Ilconich, J.B. (Parsons)

    2007-06-01

    The capture/separation step for carbon dioxide (CO2) from large-point sources is a critical one with respect to the technical feasibility and cost of the overall carbon sequestration scenario. For large-point sources, such as those found in power generation, the carbon dioxide capture techniques being investigated by the in-house research area of the National Energy Technology Laboratory possess the potential for improved efficiency and reduced costs as compared to more conventional technologies. The investigated techniques can have wide applications, but the research has focused on capture/separation of carbon dioxide from flue gas (post-combustion from fossil fuel-fired combustors) and from fuel gas (precombustion, such as integrated gasification combined cycle or IGCC). With respect to fuel gas applications, novel concepts are being developed in wet scrubbing with physical absorption; chemical absorption with solid sorbents; and separation by membranes. In one concept, a wet scrubbing technique is being investigated that uses a physical solvent process to remove CO2 from fuel gas of an IGCC system at elevated temperature and pressure. The need to define an ideal solvent has led to the study of the solubility and mass transfer properties of various solvents. Pertaining to another separation technology, fabrication techniques and mechanistic studies for membranes separating CO2 from the fuel gas produced by coal gasification are also being performed. Membranes that consist of CO2-philic ionic liquids encapsulated into a polymeric substrate have been investigated for permeability and selectivity. Finally, dry, regenerable processes based on sorbents are additional techniques for CO2 capture from fuel gas. An overview of these novel techniques is presented along with a research progress status of technologies related to membranes and physical solvents.

  3. Combined method for reducing emission of sulfur dioxide and nitrogen oxides from thermal power plants

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, V.R.; Grachev, S.P.

    1991-11-01

    Discusses the method developed by the Fossil Energy Research Corp. in the USA for combined desulfurization and denitrification of flue gases from coal-fired power plants. The method combines two methods tested on a commercial scale: the dry additive method for suppression of sulfur dioxide and the selective noncatalytic reduction of nitrogen oxides using urea (the NOXOUT process). The following aspects of joint flue gas desulfurization and denitrification are analyzed: flowsheets of the system, chemical reactions and reaction products, laboratory tests of the method and its efficiency, temperature effects on desulfurization and denitrification of flue gases, effects of reagent consumption rates, operating cost, efficiency of the combined method compared to other conventional methods of separate flue gas desulfurization and denitrification, economic aspects of flue gas denitrification and desulfurization. 4 refs.

  4. Economic research of the transcritical Rankine cycle systems to recover waste heat from the marine medium-speed diesel engine

    International Nuclear Information System (INIS)

    Yang, Min-Hsiung; Yeh, Rong-Hua

    2017-01-01

    The aim of this study is to investigate the economic performance of a transcritical Rankine cycle (TRC) system for recovering waste heat from the exhaust gas of a marine medium-speed diesel engine. The variation of net power output, total cost of equipments and exergy destruction are investigated for the TRC system. Furthermore, to evaluate the economic performance of energy utilization, a parameter, net power output index, which is the ratio of net power output to the total cost, is introduced of the TRC system using R125, R143a, R218 and R1234yf as working fluids. The results show that R1234yf performs the highest economic performance, followed by R143a, R125 and R218 of the TRC system. It reveals that R1234yf not only has the smallest high and low pressures of the TRC system for reducing the purchased cost of equipments, but also promotes a larger pressure ratio of the expander for generating power output among these working fluids. The comparisons of optimal pressure ratios obtained from thermodynamic and economic optimizations for these working fluids in the TRC system are also reported. In addition, an evaluation method using thermal efficiency and operating pressure ratio as parameters is proposed to assess the suitability of the working fluids of TRC system in economic analysis for waste heat recovery from the exhaust gas of a diesel engine.

  5. Low-Power, Chip-Scale, Carbon Dioxide Gas Sensors for Spacesuit Monitoring

    Science.gov (United States)

    Rani, Asha; Shi, Chen; Thomson, Brian; Debnath, Ratan; Wen, Boamei; Motayed, Abhishek; Chullen, Cinda

    2018-01-01

    N5 Sensors, Inc. through a Small Business Technology Transfer (STTR) contract award has been developing ultra-small, low-power carbon dioxide (CO2) gas sensors, suited for monitoring CO2 levels inside NASA spacesuits. Due to the unique environmental conditions within the spacesuits, such as high humidity, large temperature swings, and operating pressure swings, measurement of key gases relevant to astronaut's safety and health such as(CO2), is quite challenging. Conventional non-dispersive infrared absorption based CO2 sensors present challenges inside the spacesuits due to size, weight, and power constraints, along with the ability to sense CO2 in a high humidity environment. Unique chip-scale, nanoengineered chemiresistive gas-sensing architecture has been developed for this application, which can be operated in a typical space-suite environmental conditions. Unique design combining the selective adsorption properties of the nanophotocatalytic clusters of metal-oxides and metals, provides selective detection of CO2 in high relative humidity conditions. All electronic design provides a compact and low-power solution, which can be implemented for multipoint detection of CO2 inside the spacesuits. This paper will describe the sensor architecture, development of new photocatalytic material for better sensor response, and advanced structure for better sensitivity and shorter response times.

  6. 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

  7. Evaluating the impact of the carbon dioxide capturing process on the indices of economic efficiency in thermal power plants

    International Nuclear Information System (INIS)

    Marukhyan, V.Z.; Elbakyan, S.H.

    2017-01-01

    Taking into account the input of carbon dioxide as a greenhouse gas in the global warming process, the technological solutions of its capturing, and the implementation possibilities in environmentally safe thermal power plants are considered. In power plants equipped with effective systems for cleaning the fuel gas and the coal gasification, the influence of the CO 2 reduction and realization of quotes on the indices of economic efficiency is estimated

  8. Potential flue gas impurities in carbon dioxide streams separated from coal-fired power plants.

    Science.gov (United States)

    Lee, Joo-Youp; Keener, Tim C; Yang, Y Jeffery

    2009-06-01

    For geological sequestration of carbon dioxide (CO2) separated from pulverized coal combustion flue gas, it is necessary to adequately evaluate the potential impacts of flue gas impurities on groundwater aquifers in the case of the CO2 leakage from its storage sites. This study estimated the flue gas impurities to be included in the CO2 stream separated from a CO2 control unit for a different combination of air pollution control devices and different flue gas compositions. Specifically, the levels of acid gases and mercury vapor were estimated for the monoethanolamine (MEA)-based absorption process on the basis of published performance parameters of existing systems. Among the flue gas constituents considered, sulfur dioxide (SO2) is known to have the most adverse impact on MEA absorption. When a flue gas contains 3000 parts per million by volume (ppmv) SO2 and a wet flue gas desulfurization system achieves its 95% removal, approximately 2400 parts per million by weight (ppmw) SO2 could be included in the separated CO2 stream. In addition, the estimated concentration level was reduced to as low as 135 ppmw for the SO2 of less than 10 ppmv in the flue gas entering the MEA unit. Furthermore, heat-stable salt formation could further reduce the SO2 concentration below 40 ppmw in the separated CO2 stream. In this study, it is realized that the formation rates of heat-stable salts in MEA solution are not readily available in the literature and are critical to estimating the levels and compositions of flue gas impurities in sequestered CO2 streams. In addition to SO2, mercury, and other impurities in separated CO2 streams could vary depending on pollutant removal at the power plants and impose potential impacts on groundwater. Such a variation and related process control in the upstream management of carbon separation have implications for groundwater protection at carbon sequestration sites and warrant necessary considerations in overall sequestration planning

  9. Carbon dioxide emissions effects of grid-scale electricity storage in a decarbonizing power system

    Science.gov (United States)

    Craig, Michael T.; Jaramillo, Paulina; Hodge, Bri-Mathias

    2018-01-01

    While grid-scale electricity storage (hereafter ‘storage’) could be crucial for deeply decarbonizing the electric power system, it would increase carbon dioxide (CO2) emissions in current systems across the United States. To better understand how storage transitions from increasing to decreasing system CO2 emissions, we quantify the effect of storage on operational CO2 emissions as a power system decarbonizes under a moderate and strong CO2 emission reduction target through 2045. Under each target, we compare the effect of storage on CO2 emissions when storage participates in only energy, only reserve, and energy and reserve markets. We conduct our study in the Electricity Reliability Council of Texas (ERCOT) system and use a capacity expansion model to forecast generator fleet changes and a unit commitment and economic dispatch model to quantify system CO2 emissions with and without storage. We find that storage would increase CO2 emissions in the current ERCOT system, but would decrease CO2 emissions in 2025 through 2045 under both decarbonization targets. Storage reduces CO2 emissions primarily by enabling gas-fired generation to displace coal-fired generation, but also by reducing wind and solar curtailment. We further find that the market in which storage participates drives large differences in the magnitude, but not the direction, of the effect of storage on CO2 emissions.

  10. Integrated strategy for N-methylformanilide production from carbon dioxide of flue gas in coal-fired power plant

    International Nuclear Information System (INIS)

    Han, Jeehoon

    2017-01-01

    Highlights: • A ‘green’ N-methylformanilide production process based new carbon dioxide conversion technologies is developed. • Monoethanolamine-based system for capturing carbon dioxide from the flue gas of a coal-fired power plant is deployed. • Gamma-valerolactone is used a solvent and catalyst for converting carbon dioxide to N-methylformanilide. • New separations for recovery of N-methylformanilide and gamma-valerolactone are developed. • Economic evaluation of the proposed process is performed. - Abstract: In this work, an integrated strategy is developed for producing N-methylformanilide from the carbon dioxide of flue gas in a coal-fired power plant. Based on lab-scale experimental studies presenting maximum yields (96%) with low reaction concentrations (below 25 wt% reactants) using large volumes of gamma-valerolactone as a solvent and catalyst, the integrated strategy focuses on the development of commercial-scale processes that consist of a monoethanolamine-based carbon dioxide separation subsystem and a catalytic conversion subsystem of N-Methylaniline with carbon dioxide to N-methylformanilide. Moreover, a heat exchanger network is designed to minimize the total energy requirements by transferring the heat between subsystems. In the proposed integrated strategy, the energy efficiency after heat integration (77.5%) is higher than that before heat integration (74.5%). Economic analysis results show that the minimum selling price of N-methylformanilide ($1592.1 Mt"−"1 using the best possible parameters) for use in this integrated strategy is cost-competitive with the current market price ($2984 Mt"−"1).

  11. Review of carbon dioxide capture and storage with relevance to the South African power sector

    Directory of Open Access Journals (Sweden)

    Khalid Osman

    2014-05-01

    Full Text Available Carbon dioxide (CO2 emissions and their association with climate change are currently a major discussion point in government and amongst the public at large in South Africa, especially because of the country's heavy reliance on fossil fuels for electricity production. Here we review the current situation regarding CO2 emissions in the South African power generation sector, and potential process engineering solutions to reduce these emissions. Estimates of CO2 emissions are presented, with the main sources of emissions identified and benchmarked to other countries. A promising mid-term solution for mitigation of high CO2 emissions, known as CO2 capture and storage, is reviewed. The various aspects of CO2 capture and storage technology and techniques for CO2 capture from pulverised coal power plants are discussed; these techniques include processes such as gas absorption, hydrate formation, cryogenic separation, membrane usage, sorbent usage, enzyme-based systems and metal organic frameworks. The latest power plant designs which optimise CO2 capture are also discussed and include integrated gasification combined cycle, oxy-fuel combustion, integrated gasification steam cycle and chemical looping combustion. Each CO2 capture technique and plant modification is presented in terms of the conceptual idea, the advantages and disadvantages, and the extent of development and applicability in a South African context. Lastly, CO2 transportation, storage, and potential uses are also presented. The main conclusions of this review are that gas absorption using solvents is currently most applicable for CO2 capture and that enhanced coal bed methane recovery could provide the best disposal route for CO2 emissions mitigation in South Africa.

  12. 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.

  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. 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.

  15. An efficient combination of transcritical CO_2 refrigeration and multi-effect desalination: Energy and economic analysis

    International Nuclear Information System (INIS)

    Farsi, Aida; Mohammadi, S.M.Hojjat; Ameri, Mehran

    2016-01-01

    Highlights: • A novel combination of CO_2 refrigeration and MED system is analyzed from energy and economic viewpoints. • A new heating medium source in MED (supercritical CO_2) is introduced. • Heat transfer coefficients in components of the system are calculated. • In MED, supercritical CO_2 presents better heat transfer characteristics compared to steam. • In similar operating conditions, the combined cycle is more economical than single generation systems. - Abstract: This paper presents a novel combination of transcritical carbon dioxide refrigeration with Boosted-MED (Multi-Effect-Desalination) system to provide cooling and fresh water simultaneously. In the combined system a part of gas cooler in refrigeration system is replaced by the first effect and Booster module of Boosted-MED; so that a significant amount of waste heat would be recovered. Thermodynamic and economic analyses are carried out in order to investigate the proposed system’s performance. Since institution of CO_2 as a heating medium in MED systems is a novel topic; so, the heat transfer process between CO_2 and seawater is studied. Results show that the supercritical CO_2 presents an effective heat exchange process. Therefore, the specific heat transfer area would be reduced 135% and 25% compared to conventional MEDs and sensible heat source MEDs, respectively. The proposed combined system can save 57% of energy and 37.8% and 29.1% of total annual cost in Iran and Toronto respectively, compared to a stand-alone CO_2 refrigeration system and an MED-Boosted.

  16. Fly ashes from Polish power plants and combined heat and power plants and conditions of their application for carbon dioxide utilization

    Energy Technology Data Exchange (ETDEWEB)

    Uliasz-Bochenczyk, A.; Mokrzycki, E. [Polish Academy of Science, Krakow (Poland). Mineral & Energy Economic Research Institute

    2006-09-15

    Poland has large resources of hard coal and brown coal. Therefore power industry is mostly based on these two original energy carriers. The power plants producing heat and electrical energy create combustion byproducts. These products include: fly ashes, slags, carbon dioxide and other gaseous compounds. In year 2003 fly ashes emission from hard coal combustion in Poland reached 37 000 tons and over 15 000 tons from brown coal combustion. Fly ashes are widely used in the economy. They are used in building materials industry, in road building and geotechnics. CO{sub 2} emission in Poland in 2003 originating from hard coal combustion was almost 91 million tons and from brown coal combustion-almost 58 million tons. High emissions of CO{sub 2} originating from power engineering processes of coal combustion are deleterious to the natural environment, contributing to the greenhouse effect. Presently there are carried out studies aimed at limiting CO{sub 2} emission coming from industrial processes. Fly ash properties are determined by qualitative characteristics of combusted coal, its chemical composition and combustion technology. Chemical composition of Polish fly ashes is very diversified. Fly ashes with high calcium oxide content can be used for carbon dioxide fixation. Fly ash carbonation is a complicated process however safe for natural environment. Polish fly ashes coming from power engineering, conditions of their use for the carbon dioxide utilization as well as their quantitative and qualitative characteristics are the subjects of this paper.

  17. 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)

  18. Selected aspects of operation of supercritical (transcritical organic Rankine cycle

    Directory of Open Access Journals (Sweden)

    Mocarsk Szymon

    2015-06-01

    Full Text Available The paper presents a literature review on the topic of vapour power plants working according to the two-phase thermodynamic cycle with supercritical parameters. The main attention was focused on a review of articles and papers on the vapour power plants working using organic circulation fluids powered with low- and medium-temperature heat sources. Power plants with water-steam cycle supplied with a high-temperature sources have also been shown, however, it has been done mainly to show fundamental differences in the efficiency of the power plant and applications of organic and water-steam cycles. Based on a review of available literature references a comparative analysis of the parameters generated by power plants was conducted, depending on the working fluid used, the type and parameters of the heat source, with particular attention to the needs of power plant internal load.

  19. Thermodynamic analysis of transcritical CO{sub 2} booster refrigeration systems in supermarket

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Y.T., E-mail: yunting.ge@brunel.ac.u [Mechanical Engineering, School of Engineering and Design, Brunel University, Uxbridge, Middlesex UB8 3PH (United Kingdom); Tassou, S.A. [Mechanical Engineering, School of Engineering and Design, Brunel University, Uxbridge, Middlesex UB8 3PH (United Kingdom)

    2011-04-15

    Research highlights: {yields} The CO{sub 2} booster systems are widely applied in supermarket refrigeration. {yields} Control optimisation can improve the performance of the CO{sub 2} refrigeration systems. {yields} The effects of some important parameters on the system performance are examined. {yields} The optimal high-side pressure in the transcritical cycles is established and derived. -- Abstract: Due to less environmental impact, the CO{sub 2} booster refrigeration system has been widely applied in the modern supermarket as a substitute for the conventional R404A multiplex system. However, the performance efficiency of the CO{sub 2} system still requires further improvement in order to save energy; thus, one of the most efficient techniques would be to investigate and employ the optimal controls for refrigerant high side pressures at various operating states. In this paper, the possible parameters affecting system efficiency of the CO{sub 2} system in the transcritical cycle at a higher ambient air temperature are identified through thermodynamic analysis, but cannot be quantified mathematically because of the high non-linearity involved. Instead, sensitive analysis of the system by means of the thermodynamic model is used to examine the effects of parameters including high side refrigerant pressure, ambient air temperature, refrigerant intermediate pressure, and medium and low evaporating temperatures, superheating, effectiveness of suction line heat exchanger, and compressor efficiency on system performance. Consequently, the optimal high side pressure in the transcritical cycle is established and derived as a function of three important parameters consisting of ambient air temperature, the effectiveness of suction line heat exchanger and compressor efficiency. In addition, optimal operating parameters such as the intermediate pressure are also proposed to improve the system performance.

  20. Thermodynamic analysis of transcritical CO2 booster refrigeration systems in supermarket

    International Nuclear Information System (INIS)

    Ge, Y.T.; Tassou, S.A.

    2011-01-01

    Research highlights: → The CO 2 booster systems are widely applied in supermarket refrigeration. → Control optimisation can improve the performance of the CO 2 refrigeration systems. → The effects of some important parameters on the system performance are examined. → The optimal high-side pressure in the transcritical cycles is established and derived. -- Abstract: Due to less environmental impact, the CO 2 booster refrigeration system has been widely applied in the modern supermarket as a substitute for the conventional R404A multiplex system. However, the performance efficiency of the CO 2 system still requires further improvement in order to save energy; thus, one of the most efficient techniques would be to investigate and employ the optimal controls for refrigerant high side pressures at various operating states. In this paper, the possible parameters affecting system efficiency of the CO 2 system in the transcritical cycle at a higher ambient air temperature are identified through thermodynamic analysis, but cannot be quantified mathematically because of the high non-linearity involved. Instead, sensitive analysis of the system by means of the thermodynamic model is used to examine the effects of parameters including high side refrigerant pressure, ambient air temperature, refrigerant intermediate pressure, and medium and low evaporating temperatures, superheating, effectiveness of suction line heat exchanger, and compressor efficiency on system performance. Consequently, the optimal high side pressure in the transcritical cycle is established and derived as a function of three important parameters consisting of ambient air temperature, the effectiveness of suction line heat exchanger and compressor efficiency. In addition, optimal operating parameters such as the intermediate pressure are also proposed to improve the system performance.

  1. Sensitivity and Design of a Transcritical CO2 Cooling and Heating System

    DEFF Research Database (Denmark)

    Nguyen, Chan; Veje, Christian; Willatzen, Morten

    2012-01-01

    This paper presents a theoretical design study of a transcritical CO2 heat pump system for simultaneous cooling and heating. The heat pump model consists of the components: compressor, internal heat exchanger, valve, evaporator and gas cooler. The evaporator and the gas cooler are both water...... exchangers. The results show that COP is particular sensitive to the pinch temperature in the gas cooler and to the compressor isentropic efficiency but not to pressure loss. However it is found that the heat exchanger weights are very sensitive to pressure loss. The thermodynamic and heat exchanger models...

  2. Supercritical carbon dioxide Brayton power conversion cycle for battery optimized reactor integral system

    International Nuclear Information System (INIS)

    Kim, T. W.; Kim, N. H.; Suh, K. Y.

    2007-01-01

    Supercritical carbon dioxide (SCO 2 ) promises a high power conversion efficiency of the recompression Brayton cycle due to its excellent compressibility reducing the compression work at the bottom of the cycle and to a higher density than helium or steam decreasing the component size. The SCO 2 Brayton cycle efficiency as high as 45% furnishes small sized nuclear reactors with economical benefits on the plant construction and maintenance. A 23 MWth lead-cooled Battery Optimized Reactor Integral System (BORIS) is being developed as an ultra-long-life, versatile-purpose, fast-spectrum reactor. BORIS is coupled to the SCO 2 Brayton cycle needing less room relative to the Rankine steam cycle because of its smaller components. The SCO 2 Brayton cycle of BORIS consists of a 16 MW turbine, a 32 MW high temperature recuperator, a 14 MW low temperature recuperator, an 11 MW precooler and 2 and 2.8 MW compressors. Entering six heat exchangers between primary and secondary system at 19.9 MPa and 663 K, the SCO 2 leaves the heat exchangers at 19.9 MPa and 823 K. The promising secondary system efficiency of 45% was calculated by a theoretical method in which the main parameters include pressure, temperature, heater power, the turbine's, recuperators' and compressors' efficiencies, and the flow split ratio of SCO 2 going out from the low temperature recuperator. Development of Modular Optimized Brayton Integral System (MOBIS) is being devised as the SCO 2 Brayton cycle energy conversion cycle for BORIS. MOBIS consists of Loop Operating Brayton Optimization Study (LOBOS) for experimental Brayton cycle loop and Gas Advanced Turbine Operation Study (GATOS) for the SCO 2 turbine. Liquid-metal Energy Exchanger Integral System (LEXIS) serves to couple BORIS and MOBIS. LEXIS comprises Physical Aspect Thermal Operation System (PATOS) for SCO 2 thermal hydraulic characteristics, Shell-and-tube Overall Layout Optimization Study (SOLOS) for shell-and-tube heat exchanger, Printed

  3. A robust and accurate numerical method for transcritical turbulent flows at supercritical pressure with an arbitrary equation of state

    International Nuclear Information System (INIS)

    Kawai, Soshi; Terashima, Hiroshi; Negishi, Hideyo

    2015-01-01

    This paper addresses issues in high-fidelity numerical simulations of transcritical turbulent flows at supercritical pressure. The proposed strategy builds on a tabulated look-up table method based on REFPROP database for an accurate estimation of non-linear behaviors of thermodynamic and fluid transport properties at the transcritical conditions. Based on the look-up table method we propose a numerical method that satisfies high-order spatial accuracy, spurious-oscillation-free property, and capability of capturing the abrupt variation in thermodynamic properties across the transcritical contact surface. The method introduces artificial mass diffusivity to the continuity and momentum equations in a physically-consistent manner in order to capture the steep transcritical thermodynamic variations robustly while maintaining spurious-oscillation-free property in the velocity field. The pressure evolution equation is derived from the full compressible Navier–Stokes equations and solved instead of solving the total energy equation to achieve the spurious pressure oscillation free property with an arbitrary equation of state including the present look-up table method. Flow problems with and without physical diffusion are employed for the numerical tests to validate the robustness, accuracy, and consistency of the proposed approach.

  4. Reducing information asymmetry in the power industry: Mandatory and voluntary information disclosure regulations of sulfur dioxide emission

    International Nuclear Information System (INIS)

    Zhu Xufeng; Zhang Chao

    2012-01-01

    This paper focuses on the institutional framework for sulfur dioxide emission information disclosure (SDEID) in power industries. The authors argue that mandatory and voluntary SDEID are two complementary regulatory instruments for emission reduction in the power industry. An analytical framework of SDEID with six facets is suggested in this paper to demonstrate relevant legal provisions and regulatory policies of mandatory and voluntary SDEID of power industries in the US. Empirical research shows that mandatory and voluntary SDEID of the power industry have been regulated simultaneously in the US. The foundation of power companies' willingness to disclose emission information voluntarily is the combination of mandatory scientific monitoring with market regulation in the current SDEID system in the US. In comparison, the SDEID of power industries has yet to be widely implemented in developing countries. Finally, the paper provides some implications to developing countries that plan to learn institutional arrangements from developed countries. - Highlights: ► Mandatory and voluntary SDEID are two complementary regulatory instruments. ► An analytical framework is suggested to demonstrate SDEID of power industry in the US. ► Voluntary disclosure can be attributed to scientific monitoring and market regulation. ► We provide implications to developing countries learning from developed countries.

  5. 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.

  6. Reduction of carbon dioxide emissions by modernisation or substitution of existing coal power stations in the EC and the resulting cost effect

    International Nuclear Information System (INIS)

    Folke, C.

    2000-01-01

    Trends in carbon dioxide emissions and cost of coal power stations are analyzed EC-wide. The data base derives from several generations of power stations for the period between 2000 and 2050 assuming several different substitution strategies. The reference scenario is one in which decisions on new power station types are made purely on the basis of short-term economic aspects (annual minimisation of the nominal cost). The method and the parameters used for calculating and analyzing carbon dioxide strategies in the context of this study are presented and explained [de

  7. Carbon dioxide emission standards for U.S. power plants. An efficiency analysis perspective

    Energy Technology Data Exchange (ETDEWEB)

    Hampf, Benjamin [Technische Univ. Darmstadt (Germany). Fachbereich Rechts- und Wirtschaftswissenschaften; Roedseth, Kenneth Loevold [Institute of Transport Economics, Oslo (Norway). Dept. of Economics and Logistics

    2013-07-01

    On June 25, 2013, President Obama announced his plan to introduce carbon dioxide emission standards for electricity generation. This paper proposes an efficiency analysis approach that addresses which mission rates (and standards) would be feasible if the existing generating units adopt best practices. A new efficiency measure is introduced and further decomposed to identify different sources' contributions to emission rate improvements. Estimating two Data Envelopment Analysis (DEA) models - the well-known joint production model and the new materials balance model - on a dataset consisting of 160 bituminous-fired generating units, we find that the average generating unit's electricity-to-carbon dioxide ratio is 15.3 percent below the corresponding best-practice ratio. Further examinations reveal that this discrepancy can largely be attributed to non-discretionary factors and not to managerial inefficiency. Moreover, even if the best practice ratios could be implemented, the generating units would not be able to comply with the EPA's recently proposed carbon dioxide standard.

  8. Thermal and economic analyses of a compact waste heat recovering system for the marine diesel engine using transcritical Rankine cycle

    International Nuclear Information System (INIS)

    Yang, Min-Hsiung

    2015-01-01

    Graphical abstract: Schematic diagram of the CWHRS for a marine diesel engine. - Highlights: • The economic optimization of a CWHRS of a marine engine is investigated. • The environmental protection refrigerant, R1234yf is used as the working fluid of the TRC system. • The optimal analysis and comparison of three models for waste heat recovering have been carried out. • The optimization of payback periods, CO_2 emission reducing and diesel oil saving are reported. - Abstract: The aim of this study is to investigate the economic performance of a novel compact waste heat recovering system for the marine diesel engine. The transcritical Rankine cycle is employed to convert the waste heat resources to useful work with R1234yf. To evaluate the utilizing efficiency and economic performance of waste heat resources, which are exhaust gas, cylinder cooling water and scavenge air cooling water, three operating models of the system are investigated and compared. The levelized energy cost, which represents the total cost per kilo-watt power, is employed to evaluate the economic performance of the system. The economic optimization and its corresponding optimal parameters of each operating model in the compact waste heat recovering system are obtained theoretically. The results show that the minimal levelized energy cost of the proposed system operated in Model I is the lowest of the three models, and then are Model II and Model III, which are 2.96% and 9.36% lower for, respectively. Similarly, the CO_2 emission reduction is the highest for Model I of the three models, and 21.6% and 30.1% lower are obtained for Model II and Model III, respectively. The compact waste heat recovering system operated in Model I has superiority on the payback periods and heavy diesel oil saving over the others. Finally, the correlations using specific work of working fluid and condensation temperature as parameters are proposed to assess the optimal conditions in economic performance

  9. A study on the capture of carbon dioxide from a large refinery power station boiler by conversion to oxyfuel operation

    Energy Technology Data Exchange (ETDEWEB)

    Wilkinson, M.B.; Boden, J.C.; Panesar, R.S.; Allam, R.J. [BP Amoco, Sunbury-on-Thames (United Kingdom)

    2001-07-01

    A detailed feasibility study has been carried out on the conversion of an existing refinery power station boiler, fired with refinery off-gas, to oxyfuel operation with carbon dioxide capture. The conversion was shown to be technically feasible using proven technologies. Boiler output could be maintained without significant pressure-part modifications and there would be no loss of boiler efficiency. It would be possible to retain a capability to operate in conventional air firing mode for start-up and emergency situations. The concept has been developed to a stage where a demonstration plant could be designed. The major elements of the capital costs of conversion are associated with the air separation unit and the carbon dioxide treatment and compression train and the additional operating costs are associated principally with the power consumption of these units. Further optimisation of the oxyfuel combustion system is possible and it is anticipated that the ongoing developments in air separation technology will help to make significant reductions in these costs in the future. 5 refs., 6 figs.

  10. Large scale carbon dioxide production from coal-fired power stations for enhanced oil recovery : a new economic feasibility study

    International Nuclear Information System (INIS)

    Tontiwachwuthikul, P.; Chan, C.W.; Kritpiphat, W.; DeMontigny, D.; Skoropad, D.; Gelowitz, D.; Aroonwilas, A.; Mourits, F.; Wilson, M.; Ward, L.

    1998-01-01

    A study was conducted to investigate the economics of capturing carbon dioxide from coal-fired power plants to be subsequently used as a flooding agent for enhanced oil recovery (EOR) technologies. It was shown that the production of CO 2 for EOR projects can be technically and economically feasible, particularly when the concepts of cogeneration and optimization are used to reduce steam and electricity expenditures. This is done by using low-pressure steam and waste heat from various sections of the power generation process. It was shown that recovery costs could range between $0.50 to $2.00 per mscf. This translates to a recovered oil price of in the range of $17.39 to $19.95 per bbl., suggesting that even at today's low oil prices there is room for CO 2 flooding with flue gas extracted CO 2 . Practical implications for Saskatchewan were examined. 15 refs., 4 tabs., 7 figs

  11. CFD Simulations of a Regenerative Process for Carbon Dioxide Capture in Advanced Gasification Based Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Arastoopour, Hamid [Illinois Inst. of Technology, Chicago, IL (United States); Abbasian, Javad [Illinois Inst. of Technology, Chicago, IL (United States)

    2014-07-31

    estimated cost of carbon v capture is in the range of $31-$44/ton, suggesting that a regenerative MgO-Based process can be a viable option for pre-combustion carbon dioxide capture in advanced gasification based power systems.

  12. Updated (BP3) Technical and Economic Feasibility Study - Electrochemical Membrane for Carbon Dioxide Capture and Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Ghezel-Ayagh, Hossein

    2016-10-12

    This topical report summarizes the results of an updated Technical & Economic Feasibility Study (T&EFS) which was conducted in Budget Period 3 of the project to evaluate the performance and cost of the Electrochemical Membrane (ECM)-based CO2 capture system. The ECM technology is derived from commercially available inorganic membranes; the same used in FuelCell Energy’s commercial fuel cell power plants and sold under the trade name Direct FuelCell® (DFC®). The ECM stacks are utilized in the Combined Electric Power (generation) And Carbon dioxide Separation (CEPACS) systems which can be deployed as add-ons to conventional power plants (Pulverized Coal, Combined Cycle, etc.) or industrial facilities to simultaneously produce power while capturing >90% of the CO2 from the flue gas. In this study, an ECM-based CEPACS plant was designed to capture and compress >90% of the CO2 (for sequestration or beneficial use) from the flue gas of a reference 550 MW (nominal, net AC) Pulverized Coal (PC) Rankine Cycle (Subcritical steam) power plant. ECM performance was updated based on bench scale ECM stack test results. The system process simulations were performed to generate the CEPACS plant performance estimates. The performance assessment included estimation of the parasitic power consumption for CO2 capture and compression, and the efficiency impact on the PC plant. While the ECM-based CEPACS system for the 550 MW PC plant captures 90% of CO2 from the flue gas, it generates additional (net AC) power after compensating for the auxiliary power requirements of CO2 capture and compression. An equipment list, ECM stacks packaging design, and CEPACS plant layout were developed to facilitate the economic analysis. Vendor quotes were also solicited. The economic feasibility study included estimation of CEPACS plant capital cost, cost of electricity (COE) analyses and estimation of cost per ton of CO2 captured. The incremental COE for the ECM-based CO2 capture is expected to meet

  13. Updated (BP3) Technical and Economic Feasibility Study - Electrochemical Membrane for Carbon Dioxide Capture and Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Ghezel-Ayagh, Hossein [FuelCell Energy, Inc., Danbury, CT (United States)

    2017-12-21

    This topical report summarizes the results of an updated Technical & Economic Feasibility Study (T&EFS) which was conducted in Budget Period 3 of the project to evaluate the performance and cost of the Electrochemical Membrane (ECM)-based CO2 capture system. The ECM technology is derived from commercially available inorganic membranes; the same used in FuelCell Energy’s commercial fuel cell power plants and sold under the trade name Direct FuelCell® (DFC®). The ECM stacks are utilized in the Combined Electric Power (generation) And Carbon dioxide Separation (CEPACS) systems which can be deployed as add-ons to conventional power plants (Pulverized Coal, Combined Cycle, etc.) or industrial facilities to simultaneously produce power while capturing >90% of the CO2 from the flue gas. In this study, an ECM-based CEPACS plant was designed to capture and compress >90% of the CO2 (for sequestration or beneficial use) from the flue gas of a reference 550 MW (nominal, net AC) Pulverized Coal (PC) Rankine Cycle (Subcritical steam) power plant. ECM performance was updated based on bench scale ECM stack test results. The system process simulations were performed to generate the CEPACS plant performance estimates. The performance assessment included estimation of the parasitic power consumption for CO2 capture and compression, and the efficiency impact on the PC plant. While the ECM-based CEPACS system for the 550 MW PC plant captures 90% of CO2 from the flue gas, it generates additional (net AC) power after compensating for the auxiliary power requirements of CO2 capture and compression. An equipment list, ECM stacks packaging design, and CEPACS plant layout were developed to facilitate the economic analysis. Vendor quotes were also solicited. The economic feasibility study included estimation of CEPACS plant capital cost, cost of electricity (COE) analyses and estimation of cost per ton of CO2

  14. Potential reduction of carbon dioxide emissions from the use of electric energy storage on a power generation unit/organic Rankine system

    International Nuclear Information System (INIS)

    Mago, Pedro J.; Luck, Rogelio

    2017-01-01

    Highlights: • A power generation organic Rankine cycle with electric energy storage is evaluated. • The potential carbon dioxide emissions reduction of the system is evaluated. • The system performance is evaluated for a building in different climate zones. • The system emissions and cost are compared with those of conventional systems. • Use of carbon emissions cap and trade programs on the system is evaluated. - Abstract: This paper evaluates the potential carbon dioxide emissions reduction from the implementation of electric energy storage to a combined power generation unit and an organic Rankine cycle relative to a conventional system that uses utility gas for heating and utility electricity for electricity needs. Results indicate that carbon dioxide emission reductions from the operation of the proposed system are directly correlated to the ratio of the carbon dioxide emission conversion factor for electricity to that of the fuel. The location where the system is installed also has a strong influence on the potential of the proposed system to save carbon dioxide emissions. Finally, it is shown that by using carbon emissions cap and trade programs, it is possible to establish a frame of reference to compare/exchange operational cost gains with carbon dioxide emission reductions/gains.

  15. Uranium dioxide pellets

    International Nuclear Information System (INIS)

    Zawidzki, T.W.

    1979-01-01

    Sintered uranium dioxide pellets composed of particles of size > 50 microns suitable for power reactor use are made by incorporating a small amount of sulphur into the uranium dioxide before sintering. The increase in grain size achieved results in an improvement in overall efficiency when such pellets are used in a power reactor. (author)

  16. Physical and chemical processes of sulphur dioxide in the plume from an oil-fired power station

    International Nuclear Information System (INIS)

    Flyger, H.; Lewin, E.; Lund Thomsen, E.; Fenger, J.; Lyck, E.; Gryning, S.E.

    1977-03-01

    The Danish contribution to the EUROCOP COST 61a project is described. Work concerned the physical and chemical reactions of sulphur dioxide released from a power station. The investigation was based on the application of two tracers. Inactive, inert SF 6 is used to monitor the dispersion of and deposition from the plume; it was intended to use radioactive 35 SO 2 to determine the degree of oxidation of sulphur released from the stack; so far, however, public reaction has prevented the use of a release of activity in field experiments. The report describes the construction and testing of airborne instruments for continuous registration of sulphur dioxide, nitrogen oxides, ozone and the tracer SF 6 , as well as for measurements of temperature and humidity. Sulphur samples were collected on filter paper in a specially constructed low volume air sampler, and the subsequent chemical analysis in the laboratory is described. Finally, the problem of navigation is treated. It is shown that nitrogen oxides may be used as an internal tracer in plume experiments. Preliminary experiments based on inactive analysis only indicated an overall half-life for SO 2 in the plume of about half an hour. (author)

  17. Multispeed Lattice Boltzmann Model with Space-Filling Lattice for Transcritical Shallow Water Flows

    Directory of Open Access Journals (Sweden)

    Y. Peng

    2017-01-01

    Full Text Available Inspired by the recent success of applying multispeed lattice Boltzmann models with a non-space-filling lattice for simulating transcritical shallow water flows, the capabilities of their space-filling counterpart are investigated in this work. Firstly, two lattice models with five integer discrete velocities are derived by using the method of matching hydrodynamics moments and then tested with two typical 1D problems including the dam-break flow over flat bed and the steady flow over bump. In simulations, the derived space-filling multispeed models, together with the stream-collision scheme, demonstrate better capability in simulating flows with finite Froude number. However, the performance is worse than the non-space-filling model solved by finite difference scheme. The stream-collision scheme with second-order accuracy may be the reason since a numerical scheme with second-order accuracy is prone to numerical oscillations at discontinuities, which is worthwhile for further study.

  18. 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.

  19. 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.

  20. Metamorphosis of plasma turbulence-shear-flow dynamics through a transcritical bifurcation

    International Nuclear Information System (INIS)

    Ball, R.; Dewar, R.L.; Sugama, H.

    2002-01-01

    The structural properties of an economical model for a confined plasma turbulence governor are investigated through bifurcation and stability analyses. A close relationship is demonstrated between the underlying bifurcation framework of the model and typical behavior associated with low- to high-confinement transitions such as shear-flow stabilization of turbulence and oscillatory collective action. In particular, the analysis evinces two types of discontinuous transition that are qualitatively distinct. One involves classical hysteresis, governed by viscous dissipation. The other is intrinsically oscillatory and nonhysteretic, and thus provides a model for the so-called dithering transitions that are frequently observed. This metamorphosis, or transformation, of the system dynamics is an important late side-effect of symmetry breaking, which manifests as an unusual nonsymmetric transcritical bifurcation induced by a significant shear-flow drive

  1. Experimental investigation of the discharge valve dynamics in a reciprocating compressor for trans-critical CO2 refrigeration cycle

    International Nuclear Information System (INIS)

    Ma Yuan; He Zhilong; Peng Xueyuan; Xing Ziwen

    2012-01-01

    The self-acting valve has a significant influence on the efficiency and reliability of the reciprocating compressor. In the trans-critical CO 2 cycle, the large density and high pressure difference across the valve cause serious bending and impact stresses in the valve, offering great challenges for successful valve design. Experimental investigation of the valve dynamics is required in order to design a self-acting valve with a high efficiency and long life span for the trans-critical CO 2 compressor. A semi-hermetic reciprocating compressor was developed for application in CO 2 refrigeration, and a test system was incorporated into the compressor performance test rig, with a focus on investigating the dynamics of the discharge valves. With the experimental results, the movement of the valve was discussed in detail for the trans-critical CO 2 compressor, allowing for the study of the thermodynamic performance of the compressor. While varying design parameters such as pressure ratio, valve lift, spring stiffness and compressor speed, the movement of the discharge valve in the reciprocating CO 2 compressor was measured in order to investigate the major factors that influence the valve dynamics. The average valve speed increased from 0.71 m/s to 0.81 m/s as the discharge pressure changed from 7.8 MPa to 12 MPa. The experimental methods and results discussed in this paper could provide useful information for both valve testing and the optimization of their reliability in trans-critical CO 2 compressors.

  2. Field measurements of supermarket refrigeration systems. Part I: Analysis of CO2 trans-critical refrigeration systems

    International Nuclear Information System (INIS)

    Sawalha, Samer; Karampour, Mazyar; Rogstam, Jörgen

    2015-01-01

    This study investigates the refrigeration performance of three CO 2 trans-critical solutions based on field measurements. The measurements are carried out in five supermarkets in Sweden. Using the field measurements, low and medium temperature level cooling capacities and COP's are calculated for ten-minute intervals, filtered and averaged to monthly values. The results indicate that the systems using trans-critical booster system with gas removal from the intermediate vessel have relatively the highest total COP. The reasons are higher evaporation temperatures, lower internal and external superheat and higher total efficiency of booster compressors. Another important factor is gas removal from the intermediate vessel which leads to higher COP of low temperature level. Comparing the older and newer installed systems, a trend in energy efficiency improvement has been seen. The study shows this improvement originates from both changes in the system design (e.g. two stage expansion) and components efficiency improvement (e.g. higher total efficiency of compressors - lower internal superheat and higher evaporation temperatures of cabinets). - Highlights: • Five Swedish supermarkets using three CO 2 refrigeration solutions are analyzed. • A trend of improvement in energy efficiency has been observed. • Parallel CO 2 system with indirect heat rejection offers the lowest energy efficiency. • CO 2 trans-critical booster with gas removal achieves up to 35% COP improvement

  3. Parametric study of a capillary tube-suction line heat exchanger in a transcritical CO2 heat pump cycle

    International Nuclear Information System (INIS)

    Agrawal, Neeraj; Bhattacharyya, Souvik

    2008-01-01

    The capillary tube in a transcritical CO 2 system behaves differently as temperature and pressure are two independent parameters unlike those in a sub-critical cycle. A capillary tube-suction line heat exchanger (CL-SLHX) in a transcritical vapour compression cycle considering homogeneous two-phase flow is modelled in this study based on mass, energy and momentum equations. Effects of gas cooler temperature, evaporator temperature and internal diameter of capillary tube are investigated. Heat transfer rate is observed to be influenced by refrigerant quality, mass flow rate and the prevailing temperature difference. Heat transfer rate variation with gas cooler temperature is unique, recording an initial increase followed by a decrease. Frictional pressure drop influences the heat transfer; consequently, chances of re-condensation of refrigerant vapour are very marginal. Larger diameter of capillary tube leads to increase in refrigerant mass flow rate and increase in heat transfer rate as well. Shorter inlet adiabatic capillary length with larger heat exchanger length is better for heat transfer. This study is an attempt to dispel the scepticism prevailing in transcritical CO 2 system community overemphasising the need for a throttle valve to control the optimum discharge pressure

  4. Medical Radioisotope Production in a Power-Flattened ADS Fuelled with Uranium and Plutonium Dioxides

    Directory of Open Access Journals (Sweden)

    Gizem Bakır

    2016-01-01

    Full Text Available This study presents the medical radioisotope production performance of a conceptual accelerator driven system (ADS. Lead-bismuth eutectic (LBE is selected as target material. The subcritical fuel core is conceptually divided into ten equidistant subzones. The ceramic (natural U, PuO2 fuel mixture and the materials used for radioisotope production (copper, gold, cobalt, holmium, rhenium, thulium, mercury, palladium, thallium, molybdenum, and yttrium are separately prepared as cylindrical rods cladded with carbon/carbon composite (C/C and these rods are located in the subzones. In order to obtain the flattened power density, percentages of PuO2 in the mixture of UO2 and PuO2 in the subzones are adjusted in radial direction of the fuel zone. Time-dependent calculations are performed at 1000 MW thermal fission power (Pth for one hour using the BURN card. The neutronic results show that the investigated ADS has a high neutronic capability, in terms of medical radioisotope productions, spent fuel transmutation and energy multiplication. Moreover, a good quasiuniform power density is achieved in each material case. The peak-to-average fission power density ratio is in the range of 1.02–1.28.

  5. Large-eddy simulation of flow over a grooved cylinder up to transcritical Reynolds numbers

    KAUST Repository

    Cheng, W.

    2017-11-27

    We report wall-resolved large-eddy simulation (LES) of flow over a grooved cylinder up to the transcritical regime. The stretched-vortex subgrid-scale model is embedded in a general fourth-order finite-difference code discretization on a curvilinear mesh. In the present study grooves are equally distributed around the circumference of the cylinder, each of sinusoidal shape with height , invariant in the spanwise direction. Based on the two parameters, and the Reynolds number where is the free-stream velocity, the diameter of the cylinder and the kinematic viscosity, two main sets of simulations are described. The first set varies from to while fixing . We study the flow deviation from the smooth-cylinder case, with emphasis on several important statistics such as the length of the mean-flow recirculation bubble , the pressure coefficient , the skin-friction coefficient and the non-dimensional pressure gradient parameter . It is found that, with increasing at fixed , some properties of the mean flow behave somewhat similarly to changes in the smooth-cylinder flow when is increased. This includes shrinking and nearly constant minimum pressure coefficient. In contrast, while the non-dimensional pressure gradient parameter remains nearly constant for the front part of the smooth cylinder flow, shows an oscillatory variation for the grooved-cylinder case. The second main set of LES varies from to with fixed . It is found that this range spans the subcritical and supercritical regimes and reaches the beginning of the transcritical flow regime. Mean-flow properties are diagnosed and compared with available experimental data including and the drag coefficient . The timewise variation of the lift and drag coefficients are also studied to elucidate the transition among three regimes. Instantaneous images of the surface, skin-friction vector field and also of the three-dimensional Q-criterion field are utilized to further understand the dynamics of the near-surface flow

  6. Adapting sustainable low-carbon techologies to reduce carbon dioxide emissions from coal-fired power plants in China

    Science.gov (United States)

    Kuo, Peter Shyr-Jye

    1997-09-01

    The scientific community is deeply concerned about the effect of greenhouse-gases (GHGs) on global climate change. A major climate shift can result in tragic destruction to our world. Carbon dioxide (COsb2) emissions from coal-fired power plants are major anthropogenic sources that contribute to potential global warming. The People's Republic of China, with its rapidly growing economy and heavy dependence on coal-fired power plants for electricity, faces increasingly serious environmental challenges. This research project seeks to develop viable methodologies for reducing the potential global warming effects and serious air pollution arising from excessive coal burning. China serves as a case study for this research project. Major resolution strategies are developed through intensive literature reviews to identify sustainable technologies that can minimize adverse environmental impacts while meeting China's economic needs. The research thereby contributes technological knowledge to the field of Applied Sciences. The research also integrates modern power generation technologies with China's current and future energy requirements. With these objectives in mind, this project examines how China's environmental issues are related to China's power generation methods. This study then makes strategic recommendations that emphasize low-carbon technologies as sustainable energy generating options to be implemented in China. These low-carbon technologies consist of three options: (1) using cleaner fuels converted from China's plentiful domestic coal resources; (2) applying high-efficiency gas turbine systems for power generation; and (3) integrating coal gasification processes with energy saving combined cycle gas turbine systems. Each method can perform independently, but a combined strategy can achieve the greatest COsb2 reductions. To minimize economic impacts caused by technological changes, this study also addresses additional alternatives that can be implemented in

  7. Exploring the options for carbon dioxide mitigation in Turkish electric power industry: System dynamics approach

    International Nuclear Information System (INIS)

    Saysel, Ali Kerem; Hekimoğlu, Mustafa

    2013-01-01

    Electric power industry has a huge carbon mitigation potential, fundamentally because there are large carbon-free, renewable resource options. In Turkey, with growing demand in electricity consumption and incentives offered for natural gas fired electricity generation, CO 2 emissions sourced from electric power industry had tripled over the last two decades. Current governmental strategy focuses on energy security and resource diversity in a growing economy and does not articulate sufficient mitigation targets and appropriate regulations. In this research, an original dynamic simulation model is built, validated and analyzed to explore the options for carbon mitigation in Turkish electric power industry. Model structure represents the investment, dispatch and pricing heuristics as well as the natural resource base of electricity generation in Turkey. It operates on annual basis over 30 years to simulate installed capacities and generations of power plants with alternative resources and their resulting CO 2 emissions. The analysis presented in this paper reveals that there are mitigation options below 50% of business as usual growth, with common policy options such as feed-in-tariffs, investment subsidies and carbon taxes. The model can serve as an experimental platform for further analysis of problems related to carbon mitigation in Turkish electricity sector. - Highlights: • An original computer model is created to investigate carbon mitigation. • It is holistic and comprises investment, generation, dispatch, and resources. • The model's structure, information base and foresights are specific to Turkey. • Direct and indirect strategies are explored and integrated. • Dramatic reductions are possible only with supply side strategies

  8. Supercritical Carbon Dioxide Power Generation System Definition: Concept Definition and Capital Cost Estimate

    Energy Technology Data Exchange (ETDEWEB)

    Stoddard, Larry [Black & Veatch, Kansas City, MO (United States); Galluzzo, Geoff [Black & Veatch, Kansas City, MO (United States); Andrew, Daniel [Black & Veatch, Kansas City, MO (United States); Adams, Shannon [Black & Veatch, Kansas City, MO (United States)

    2016-06-30

    The Department of Energy’s (DOE’s) Office of Renewable Power (ORP) has been tasked to provide effective program management and strategic direction for all of the DOE’s Energy Efficiency & Renewable Energy’s (EERE’s) renewable power programs. The ORP’s efforts to accomplish this mission are aligned with national energy policies, DOE strategic planning, EERE’s strategic planning, Congressional appropriation, and stakeholder advice. ORP is supported by three renewable energy offices, of which one is the Solar Energy Technology Office (SETO) whose SunShot Initiative has a mission to accelerate research, development and large scale deployment of solar technologies in the United States. SETO has a goal of reducing the cost of Concentrating Solar Power (CSP) by 75 percent of 2010 costs by 2020 to reach parity with base-load energy rates, and 30 percent further reductions by 2030. The SunShot Initiative is promoting the implementation of high temperature CSP with thermal energy storage allowing generation during high demand hours. The SunShot Initiative has funded significant research and development work on component testing, with attention to high temperature molten salts, heliostats, receiver designs, and high efficiency high temperature supercritical CO2 (sCO2) cycles. DOE retained Black & Veatch to support SETO’s SunShot Initiative for CSP solar power tower technology in the following areas: 1. Concept definition, including costs and schedule, of a flexible test facility to be used to test and prove components in part to support financing. 2. Concept definition, including costs and schedule, of an integrated high temperature molten salt (MS) facility with thermal energy storage and with a supercritical CO2 cycle generating approximately 10MWe. 3. Concept definition, including costs and schedule, of an integrated high temperature falling particle facility with thermal energy storage and with a supercritical CO2 cycle

  9. Carbon dioxide absorber and regeneration assemblies useful for power plant flue gas

    Science.gov (United States)

    Vimalchand, Pannalal; Liu, Guohai; Peng, Wan Wang

    2012-11-06

    Disclosed are apparatus and method to treat large amounts of flue gas from a pulverized coal combustion power plant. The flue gas is contacted with solid sorbents to selectively absorb CO.sub.2, which is then released as a nearly pure CO.sub.2 gas stream upon regeneration at higher temperature. The method is capable of handling the necessary sorbent circulation rates of tens of millions of lbs/hr to separate CO.sub.2 from a power plant's flue gas stream. Because pressurizing large amounts of flue gas is cost prohibitive, the method of this invention minimizes the overall pressure drop in the absorption section to less than 25 inches of water column. The internal circulation of sorbent within the absorber assembly in the proposed method not only minimizes temperature increases in the absorber to less than 25.degree. F., but also increases the CO.sub.2 concentration in the sorbent to near saturation levels. Saturating the sorbent with CO.sub.2 in the absorber section minimizes the heat energy needed for sorbent regeneration. The commercial embodiments of the proposed method can be optimized for sorbents with slower or faster absorption kinetics, low or high heat release rates, low or high saturation capacities and slower or faster regeneration kinetics.

  10. Analysis of thermodynamics of two-fuel power unit integrated with a carbon dioxide separation plant

    Directory of Open Access Journals (Sweden)

    Kotowicz Janusz

    2014-12-01

    Full Text Available The article presents the results of thermodynamic analysis of the supercritical coal-fired power plant with gross electrical output of 900 MW and a pulverized coal boiler. This unit is integrated with the absorption-based CO2 separation installation. The heat required for carrying out the desorption process, is supplied by the system with the gas turbine. Analyses were performed for two variants of the system. In the first case, in addition to the gas turbine there is an evaporator powered by exhaust gases from the gas turbine expander. The second expanded variant assumes the application of gas turbine combined cycle with heat recovery steam generator and backpressure steam turbine. The way of determining the efficiency of electricity generation and other defined indicators to assess the energy performance of the test block was showed. The size of the gas turbine system was chosen because of the need for heat for the desorption unit, taking the value of the heat demand 4 MJ/kg CO2. The analysis results obtained for the both variants of the installation with integrated CO2 separation plant were compared with the results of the analysis of the block where the separation is not conducted.

  11. Modification and application of the ATHLET-SC code to trans-critical simulations

    International Nuclear Information System (INIS)

    Fu, S.-W.; Zhou, C.; Xu, Z.-H.; Liu, X.-J.; Yang, Y.-H.; Cheng, H.

    2011-01-01

    In the simulation of trans-critical transients of Supercritical water cooled reactor (SCWR), calculation will terminate because of the sudden change in void fraction across the critical point. To solve this problem, a pseudo two-phase method is proposed with a virtual region of latent heat at pseudo-critical temperatures. A smooth variation of void fraction can be realized by using liquid-field conservation equations at temperatures lower than the pseudo-critical temperature, and vapor-field conservation equations at temperatures higher than the pseudo-critical temperature. Using this method, the system code ATHLET is modified to ATHLET-SC mod 2 on the basic of the previous modified version ATHLET-SC by Shanghai Jiao Tong University. The results of tests are verified that the calculation error with the pseudo two-phase method for supercritical fluid is acceptable, when the virtual region of latent heat is kept small. Moreover, the ATHLET-SC mod 2 code is used to simulate the pressurization and depressurization process of a single flow channel with the pressure transition as well as blowdown process. The results indicate a good applicability of the modified code. (author)

  12. Advanced exergy analyses of an ejector expansion transcritical CO_2 refrigeration system

    International Nuclear Information System (INIS)

    Bai, Tao; Yu, Jianlin; Yan, Gang

    2016-01-01

    Highlights: • Advanced exergy analyses are performed on CO_2 EERC cycle. • Compressor should be improved first, followed by ejector, evaporator and gas cooler. • Interactions among the system components are assessed with advanced exergy analysis. • Real potential for exergy destruction reduction of the system is 43.44%. - Abstract: This paper presents a thermodynamic investigation on an ejector expansion transcritical CO_2 refrigeration system with advanced exergy analysis. By splitting the exergy destruction into endogenous/exogenous and unavoidable/avoidable parts, more valuable information of the interactions among the system components and the components improvement potential is provided. The results indicate that the compressor with largest avoidable endogenous exergy destruction possesses the highest priority of improvement, followed by the ejector, evaporator and gas cooler. The system exergy destruction is dominantly endogenous, and 43.44% of the total exergy destruction can be avoided by improving the system components. The evaporator has a serious impact on the exogenous exergy destruction within the compressor and ejector, and its own exergy destruction is entirely belongs to endogenous part. The effects of the discharge pressure, compressor efficiency and ejector efficiency on the system exergetic performance are discussed. There is an optimal discharge pressure with respect to the minimum endogenous exergy destruction in the compressor. Avoidable endogenous exergy destruction rates of the compressor and ejector are respectively reduced by 93.6% and 81.7% when the corresponding component efficiency varies from 0.5 to 0.9.

  13. 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.

  14. Breakup, instabilities, and dynamics of high-speed droplet under transcritical conditions

    Directory of Open Access Journals (Sweden)

    Yanfei Gao

    2015-06-01

    Full Text Available A droplet breakup model is developed for a single droplet introduced into transcritical and strong convective environments. The numerical model takes into account variable thermophysical properties, gas solubility in the liquid phase, and vapor–liquid interfacial thermodynamics. The influences of ambient conditions on droplet breakup characteristics are investigated. The results indicate that (1 the drag acceleration decreases slowly at first and then increases drastically with the initial droplet temperature increasing, but always increases at a constant rate with ambient pressure; (2 the pressure and the drop temperature have similar effects on the Kelvin–Helmholtz and Rayleigh–Taylor wave growth at high pressures (reduced pressure higher than 1.2 and high temperatures (reduced temperature higher than 0.7, but the impact of pressure on the wave growth is relatively stronger than that of droplet temperature at relatively low pressures (reduced pressure lower than 0.8 and low temperatures (reduced temperature lower than 0.63; (3 the temperature significantly affects the surface instability growth at high drop temperatures (reduced temperature higher than 0.7, but has no effect on the instability growth at low temperatures (reduced temperature lower than 0.63.

  15. 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

  16. Expert assessments of retrofitting coal-fired power plants with carbon dioxide capture technologies

    International Nuclear Information System (INIS)

    Chung, Timothy S.; Patino-Echeverri, Dalia; Johnson, Timothy L.

    2011-01-01

    A set of 13 US based experts in post-combustion and oxy-fuel combustion CO 2 capture systems responded to an extensive questionnaire asking their views on the present status and future expected performance and costs for amine-based, chilled ammonia, and oxy-combustion retrofits of coal-fired power plants. This paper presents the experts' responses for technology maturity, ideal plant characteristics for early adopters, and the extent to which R and D and deployment incentives will impact costs. It also presents the best estimates and 95% confidence limits of the energy penalties associated with amine-based systems. The results show a general consensus that amine-based systems are closer to commercial application, but potential for improving performance and lowering costs is limited; chilled ammonia and oxy-combustion offer greater potential for cost reductions, but not without greater uncertainty regarding scale and technical feasibility. - Highlights: → Study presents experts' views on CCS retrofit costs and performance. → Experts commented on amine-based systems, chilled ammonia, and oxy-fuel combustion. → Estimates of future energy penalty show uncertainty for the three technologies. → These estimates under an aggressive RD and D policy scenario narrow significantly. → The experts' judgments support the need for enhanced RD and D for post-combustion CCS.

  17. Physico-chemical conversion of sulphur dioxide in a power plant plume

    International Nuclear Information System (INIS)

    Lewin, E.E.

    1978-03-01

    A review is given of the actual knowledge of SO 2 atmospheric processes gained from laboratory and field experiments. Implementation is described of the instrumentation, operational procedures and analytical methods in connection with a field study of the conversion and dispersion of SO 2 in an oil-fired power plant plume. Furthermore, the preliminary results are included of five experiments performed until the end of 1976. Measurements were performed from an aircraft and included continuous registration of NOsub(x), SO 2 , SF 6 , and particle concentrations, as well as temperature and humidity. It was planned to label sulphur from the source in question with sulphur-35. However, this part of the experiment had to be abandoned because of public opinion on the use of radioactive tracers. Sulphur hexafluoride was used as an internal tracer for the plume. A half-life for SO 2 of about 30 min was determined from one of the experiments. In this connection the possibility of using NOsub(x) as a conservative tracer is shown. Possible ways of removal are discussed and the rate of two of the processes is calculated by means of a model describing the chemical conversion in a dispersing plume. (author)

  18. Expert assessments of retrofitting coal-fired power plants with carbon dioxide capture technologies

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Timothy S. [Eastern Research Group, Inc., 110 Hartwell Avenue 1, Lexington, MA 02421-3134l (United States); Patino-Echeverri, Dalia, E-mail: dalia.patino@duke.edu [Nicholas School of the Environment, Box 90328, Duke University, Durham NC 27708 (United States); Johnson, Timothy L. [Nicholas School of the Environment, Box 90328, Duke University, Durham NC 27708 (United States)

    2011-09-15

    A set of 13 US based experts in post-combustion and oxy-fuel combustion CO{sub 2} capture systems responded to an extensive questionnaire asking their views on the present status and future expected performance and costs for amine-based, chilled ammonia, and oxy-combustion retrofits of coal-fired power plants. This paper presents the experts' responses for technology maturity, ideal plant characteristics for early adopters, and the extent to which R and D and deployment incentives will impact costs. It also presents the best estimates and 95% confidence limits of the energy penalties associated with amine-based systems. The results show a general consensus that amine-based systems are closer to commercial application, but potential for improving performance and lowering costs is limited; chilled ammonia and oxy-combustion offer greater potential for cost reductions, but not without greater uncertainty regarding scale and technical feasibility. - Highlights: > Study presents experts' views on CCS retrofit costs and performance. > Experts commented on amine-based systems, chilled ammonia, and oxy-fuel combustion. > Estimates of future energy penalty show uncertainty for the three technologies. > These estimates under an aggressive RD and D policy scenario narrow significantly. > The experts' judgments support the need for enhanced RD and D for post-combustion CCS.

  19. Development and assessment of a sub-channel code applicable for trans-critical transient of SCWR

    International Nuclear Information System (INIS)

    Liu, X.J.; Yang, T.; Cheng, X.

    2013-01-01

    Highlights: • A new sub-channel code COBRA-SC for SCWR is developed. • Pseudo two-phase method is employed to realize trans-critical transient calculation. • Good suitability of COBRA-SC is demonstrated by preliminary assessment. • The calculation results of COBRA-SC agree well with ATHLET code. -- Abstract: In the last few years, extensive R and D activities have been launched covering various aspects of supercritical water-cooled reactor (SCWR), especially the thermal-hydraulic analysis. Sub-channel code plays an indispensable role to predict the detail thermal-hydraulic behavior of the SCWR fuel assembly. This paper develops a new version of sub-channel code COBRA-SC based on the previous COBRA-IV code. The supercritical water property and heat transfer/pressure drop correlations under supercritical pressure are implemented to this code. Moreover, in order to simulate the trans-critical transient (the pressure undergo a decrease from the supercritical pressure to the subcritical pressure), pseudo two-phase method is employed in COBRA-SC code. This work is completed by introduction of a virtual two-phase region near the pseudo-critical line. A smooth transition of void fraction can be realized. In addition, several heat transfer correlations right underneath the critical point are introduced into this code to capture the heat transfer behavior during the trans-critical transient. Some experimental data from simple geometry, e.g. the single tube, small rod bundle, is used to validate and evaluate this new developed COBRA-SC code. The predicted results show a good agreement with the experimental data, demonstrating good feasibility of this code for SCWR condition. A code to code comparison between COBRA-SC and ATHLET for a blowdown transient of a small fuel assembly is also presented and discussed in this paper

  20. A thermodynamic analysis of a transcritical cycle with refrigerant mixture R32/R290 for a small heat pump water heater

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jianlin; Xu, Zong; Tian, Gaolei [Department of Refrigeration and Cryogenic Engineering, School of Energy and Power Engineering, Xi' an Jiaotong University, West Xianning Road, No. 28, Xianning West Road, Xi' an Shaanxi 710049 (China)

    2010-12-15

    In this study, a thermodynamic analysis on the performance of a transcritical cycle using azeotropic refrigerant mixtures of R32/R290 with mass fraction of 70/30 has been performed. The main purpose of this study is to theoretically verify the possibility of applying the chosen refrigerant mixture in small heat pumps for high temperature water heating applications. Performance evaluation has been carried out for a simple azeotropic mixture R32/R290 transcritical cycle by varying evaporator temperature, outlet temperature of gas cooler and compressor discharge pressure. Furthermore, the effects of an internal heat exchanger on the transcritical R32/R290 cycle have been presented at different operating conditions. The results show that high heating coefficient of performance (COP{sub h}) and volumetric heating capacity can be achieved by using this transcritical cycle. It is desirable to apply the chosen refrigerant mixture R32/R290 in small heat pump water heater for high temperature water heating applications, which may produce hot water with temperature up to 90 C. (author)

  1. 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.

  2. 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.

  3. A Microalgae-Based Platform for the Beneficial Re-use of Carbon Dioxide Emissions from Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Crocker, Mark; Groppo, Jack; Kesner, Stephanie; Mohler, Daniel; Pace, Robby; Santillan-Jimenez, Eduardo; Wilson, Michael; Schambach, Jenna; Stewart, Jennifer; Zeller, Ashton

    2018-02-02

    This project sought to address the technical and economic barriers to carbon dioxide capture and utilization using microalgae. Operating data were collected in 2016 and 2017 during cultivation of Scenedesmus acutus at Duke Energy’s East Bend Station – a coal-fired power plant located in northern Kentucky – using flue gas as the CO2 source. Algae were grown in a 1200 L “cyclic flow” photobioreactor (PBR) designed by the University of Kentucky. A key finding was that the harvested algae contained only very low concentrations of heavy metals (As, Cd, Hg, Se), consistent with heavy metals incorporation from the supplied nutrients. This indicates that algal biomass produced from coal-derived flue gas would be suitable for a variety of applications, including the production of bioplastics, use as fertilizer, etc. A lifecycle assessment showed that the UK-designed PBR employed in this work qualifies as a net CO2 capture technology. Indeed, over a 30-year period, net CO2 capture would equate to 43% of the targeted amount, i.e., the amount captured from the supplied flue gas. A techno-economic analysis indicated that the minimum production cost of Scenedesmus acutus biomass in the US is in the order of $875/ton, excluding the cost of capital. While this figure is not too dissimilar to values reported for open raceway ponds in similar scenarios, it emphasizes that for current cultivation technology any pathway to economic viability will require applications for which algal boimass can be sold at prices in excess of $1,000/ton. Currently, such applications represent relatively small markets, such as pigments (e.g., astaxanthin) and nutraceuticals (ω-3 unsaturated fatty acids), as well as nutritional supplements (whole algae) for human consumption and for use in pet food. Consequently, the commercialization of large-scale algae-based CO2 capture and utilization will require the development of new technologies to reduce the cost of

  4. Numerical heat transfer analysis of transcritical hydrocarbon fuel flow in a tube partially filled with porous media

    Directory of Open Access Journals (Sweden)

    Jiang Yuguang

    2016-01-01

    Full Text Available Hydrocarbon fuel has been widely used in air-breathing scramjets and liquid rocket engines as coolant and propellant. However, possible heat transfer deterioration and threats from local high heat flux area in scramjet make heat transfer enhancement essential. In this work, 2-D steady numerical simulation was carried out to study different schemes of heat transfer enhancement based on a partially filled porous media in a tube. Both boundary and central layouts were analyzed and effects of gradient porous media were also compared. The results show that heat transfer in the transcritical area is enhanced at least 3 times with the current configuration compared to the clear tube. Besides, the proper use of gradient porous media also enhances the heat transfer compared to homogenous porous media, which could help to avoid possible over-temperature in the thermal protection.

  5. Study on energy-saving performance of a transcritical CO2 heat pump for food thermal process applications

    Science.gov (United States)

    Liu, Yefeng; Meng, Deren; Chen, Shen

    2018-02-01

    In food processing, there are significant simultaneous demands of cooling, warm water and hot water. Most of the heated water is used only once rather than recycled. Current heating and cooling systems consume much energy and emit lots of greenhouse gases. In order to reduce energy consumption and greenhouse gases emission, a transcritical CO2 heat pump system is proposed that can supply not only cooling, but also warm water and hot water simultaneously to meet the thermal demands of food processing. Because the inlet water temperature from environment varies through a year, the energy-saving performance for different seasons is simulated. The results showed that the potential primary energy saving rate of the proposed CO2 heat pump is 50% to 60% during a year.

  6. Multi-Objective Thermo-Economic Optimization Strategy for ORCs Applied to Subcritical and Transcritical Cycles for Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Steven Lecompte

    2015-04-01

    Full Text Available Organic Rankine cycles (ORCs are an established technology to convert waste heat to electricity. Although several commercial implementations exist, there is still considerable potential for thermo-economic optimization. As such, a novel framework for designing optimized ORC systems is proposed based on a multi-objective optimization scheme in combination with financial appraisal in a post-processing step. The suggested methodology provides the flexibility to quickly assess several economic scenarios and this without the need of knowing the complex design procedure. This novel way of optimizing and interpreting results is applied to a waste heat recovery case. Both the transcritical ORC and subcritical ORC are investigated and compared using the suggested optimization strategy.

  7. 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

  8. Trade-off in emissions of acid gas pollutants and of carbon dioxide in fossil fuel power plants with carbon capture

    International Nuclear Information System (INIS)

    Tzimas, Evangelos; Mercier, Arnaud; Cormos, Calin-Cristian; Peteves, Stathis D.

    2007-01-01

    This paper investigates the impact of capture of carbon dioxide (CO 2 ) from fossil fuel power plants on the emissions of nitrogen oxides (NO X ) and sulphur oxides (SO X ), which are acid gas pollutants. This was done by estimating the emissions of these chemical compounds from natural gas combined cycle and pulverized coal plants, equipped with post-combustion carbon capture technology for the removal of CO 2 from their flue gases, and comparing them with the emissions of similar plants without CO 2 capture. The capture of CO 2 is not likely to increase the emissions of acid gas pollutants from individual power plants; on the contrary, some NO X and SO X will also be removed during the capture of CO 2 . The large-scale implementation of carbon capture is however likely to increase the emission levels of NO X from the power sector due to the reduced efficiency of power plants equipped with capture technologies. Furthermore, SO X emissions from coal plants should be decreased to avoid significant losses of the chemicals that are used to capture CO 2 . The increase in the quantity of NO X emissions will be however low, estimated at 5% for the natural gas power plant park and 24% for the coal plants, while the emissions of SO X from coal fired plants will be reduced by as much as 99% when at least 80% of the CO 2 generated will be captured

  9. Formate dehydrogenases and hydrogenases in syntrophic propionate-oxidizing communities : gene analysis and transcritional profiling

    NARCIS (Netherlands)

    Worm, P.

    2010-01-01

    Many places on earth are without oxygen (anaerobic) such as rice paddy fields, swamps
    and sediments of freshwater lakes and oceans. When oxygen, nitrate or other electron
    acceptors are not present, organic material is degraded to carbon dioxide and methane
    by mixed microbial

  10. An experimental study of trans-critical CO2 water–water heat pump using compact tube-in-tube heat exchangers

    International Nuclear Information System (INIS)

    Jiang, Yuntao; Ma, Yitai; Li, Minxia; Fu, Lin

    2013-01-01

    Highlights: • Thermodynamic analyses of transcritical CO 2 cycle with and without IHX are provided. • A transcritical CO 2 heat pump system adopts compact tube-in-tube heat exchangers. • Experiment results of systems with and without IHX have been analyzed and compared. • IHX can improve the performance of the transcritical CO 2 heat pump system. - Abstract: A transcritical CO 2 water–water heat pump system is introduced in this study, which employs compact tube-in-tube evaporator and gas cooler. Its primary test standards and operating conditions are introduced. Under test conditions, experiments have been carried out with compression cycles with and without internal heat exchanger (IHX). Experiment results have been analyzed and compared, showing that IHX can improve the coefficient of performance of the system. The analyses are done mainly on the variations of outlet CO 2 temperature of the gas cooler, compressor discharge pressure, compressor lubricant temperature, hot water mass flow rate, etc. When the inlet water temperature of the gas cooler is 15 °C, 20 °C, 25 °C respectively, the hot water temperature ranges from 45 °C to 70 °C, the relative COP h (coefficient of performance when heating) change index (RCI COP ) of the heat pump system with IHX is about 3.5–8% higher than that without IHX. The relative capacity change index (RCI Q ) of the heat pump system with IHX is about 5–10% higher than that without IHX. Temperature of CO 2 increases at the outlet of the gas cooler when the outlet water temperature of the gas cooler increases. Lowering the outlet CO 2 temperature of the gas cooler is an important way to improve the performance of the system

  11. Contribution of nitrogen oxide and sulfur dioxide exposure from power plant emissions on respiratory symptom and disease prevalence

    International Nuclear Information System (INIS)

    Amster, Eric D.; Haim, Maayan; Dubnov, Jonathan; Broday, David M.

    2014-01-01

    This study investigates the association between exposure to ambient NO x and SO 2 originating from power plant emissions and prevalence of obstructive pulmonary disease and related symptoms. The Orot Rabin coal-fired power plant is the largest power generating facility in the Eastern Mediterranean. Two novel methods assessing exposure to power plant-specific emissions were estimated for 2244 participants who completed the European Community Respiratory Health Survey. The “source approach” modeled emissions traced back to the power plant while the “event approach” identified peak exposures from power plant plume events. Respiratory symptoms, but not prevalence of asthma and COPD, were associated with estimates of power plant NO x emissions. The “source approach” yielded a better estimate of exposure to power plant emissions and showed a stronger dose–response relationship with outcomes. Calculating the portion of ambient pollution attributed to power plants emissions can be useful for air quality management purposes and targeted abatement programs. -- Highlights: • Two methods assessing NO x and SO 2 exposure attributed to a coal-fired power plant are utilized. • Exposure estimates are compared with respiratory outcomes in 2244 participants. • Power plant nitrogen oxide emissions are associated with respiratory symptoms. • Stack emission models correlated closest with health outcomes. -- Chronic cough, nocturnal dyspnea, chronic phlegm, and shortness of breath were significantly associated with exposure estimates of power plant-specific NO x emissions

  12. Deposition of carbon dioxide

    International Nuclear Information System (INIS)

    2001-01-01

    In Norway, there is currently a debate about whether or not to build gas power stations. To meet the possibility of reduced emission quotas for carbon dioxide in the future, current interest focuses on the incorporation of large-scale separation and deposition of carbon dioxide when such plants are planned. A group of experts concludes that this technology will become self-financing by means of environmental taxes. From the environmental point of view, taxes upon production are to be preferred over taxes on consumption

  13. Dry syngas purification process for coal gas produced in oxy-fuel type integrated gasification combined cycle power generation with carbon dioxide capturing feature.

    Science.gov (United States)

    Kobayashi, Makoto; Akiho, Hiroyuki

    2017-12-01

    Electricity production from coal fuel with minimizing efficiency penalty for the carbon dioxide abatement will bring us sustainable and compatible energy utilization. One of the promising options is oxy-fuel type Integrated Gasification Combined Cycle (oxy-fuel IGCC) power generation that is estimated to achieve thermal efficiency of 44% at lower heating value (LHV) base and provide compressed carbon dioxide (CO 2 ) with concentration of 93 vol%. The proper operation of the plant is established by introducing dry syngas cleaning processes to control halide and sulfur compounds satisfying tolerate contaminants level of gas turbine. To realize the dry process, the bench scale test facility was planned to demonstrate the first-ever halide and sulfur removal with fixed bed reactor using actual syngas from O 2 -CO 2 blown gasifier for the oxy-fuel IGCC power generation. Design parameter for the test facility was required for the candidate sorbents for halide removal and sulfur removal. Breakthrough test was performed on two kinds of halide sorbents at accelerated condition and on honeycomb desulfurization sorbent at varied space velocity condition. The results for the both sorbents for halide and sulfur exhibited sufficient removal within the satisfactory short depth of sorbent bed, as well as superior bed conversion of the impurity removal reaction. These performance evaluation of the candidate sorbents of halide and sulfur removal provided rational and affordable design parameters for the bench scale test facility to demonstrate the dry syngas cleaning process for oxy-fuel IGCC system as the scaled up step of process development. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Process development and exergy cost sensitivity analysis of a hybrid molten carbonate fuel cell power plant and carbon dioxide capturing process

    Science.gov (United States)

    Mehrpooya, Mehdi; Ansarinasab, Hojat; Moftakhari Sharifzadeh, Mohammad Mehdi; Rosen, Marc A.

    2017-10-01

    An integrated power plant with a net electrical power output of 3.71 × 105 kW is developed and investigated. The electrical efficiency of the process is found to be 60.1%. The process includes three main sub-systems: molten carbonate fuel cell system, heat recovery section and cryogenic carbon dioxide capturing process. Conventional and advanced exergoeconomic methods are used for analyzing the process. Advanced exergoeconomic analysis is a comprehensive evaluation tool which combines an exergetic approach with economic analysis procedures. With this method, investment and exergy destruction costs of the process components are divided into endogenous/exogenous and avoidable/unavoidable parts. Results of the conventional exergoeconomic analyses demonstrate that the combustion chamber has the largest exergy destruction rate (182 MW) and cost rate (13,100 /h). Also, the total process cost rate can be decreased by reducing the cost rate of the fuel cell and improving the efficiency of the combustion chamber and heat recovery steam generator. Based on the total avoidable endogenous cost rate, the priority for modification is the heat recovery steam generator, a compressor and a turbine of the power plant, in rank order. A sensitivity analysis is done to investigate the exergoeconomic factor parameters through changing the effective parameter variations.

  15. A multi-period superstructure optimisation model for the optimal planning of China's power sector considering carbon dioxide mitigation

    International Nuclear Information System (INIS)

    Zhang Dongjie; Ma Linwei; Liu Pei; Zhang Lili; Li Zheng

    2012-01-01

    Power sector is the largest CO 2 emitter in China. To mitigate CO 2 emissions for the power sector is a tough task, which requires implementation of targeted carbon mitigation policies. There might be multiple forms for carbon mitigation policies and it is still unclear which one is the best for China. Applying a superstructure optimisation model for optimal planning of China's power sector built by the authors previously, which was based on real-life plants composition data of China's power sector in 2009, and could incorporate all possible actions of the power sector, including plants construction, decommission, and application of carbon capture and sequestration (CCS) on coal-fuelled plants, the implementation effects of three carbon mitigation policies were studied quantitatively, achieving a conclusion that the so-called “Surplus-Punishment and Deficit-Award” carbon tax policy is the best from the viewpoint of increasing CO 2 reduction effect and also reducing the accumulated total cost. Based on this conclusion, the corresponding relationships between CO 2 reduction objectives (including the accumulated total emissions reduction by the objective year and the annual emissions reduction in the objective year) were presented in detail. This work provides both directional and quantitative suggestions for China to make carbon mitigation policies in the future. - Highlights: ► We study the best form of carbon mitigation policy for China's power sector. ► We gain quantitative relationship between CO 2 reduction goal and carbon tax policy. ► The “Surplus-Punishment and Deficit-Award” carbon tax policy is the best. ► Nuclear and renewable power and CCS can help greatly reduce CO 2 emissions of the power sector. ► Longer objective period is preferred from the viewpoint of policy making.

  16. A research needs assessment for the capture, utilization and disposal of carbon dioxide from fossil fuel-fired power plants. Volume 2, Topical reports: Final report

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    This study, identifies and assesses system approaches in order to prioritize research needs for the capture and non-atmospheric sequestering of a significant portion of the carbon dioxide (CO{sub 2}) emitted from fossil fuel-fired electric power plants (US power plants presently produce about 7% of the world`s CO{sub 2} emissions). The study considers capture technologies applicable either to existing plants or to those that optimistically might be demonstrated on a commercial scale over the next twenty years. The research needs that have high priority in establishing the technical, environmental, and economic feasibility of large-scale capture and disposal of CO{sub 2} from electric power plants are:(1) survey and assess the capacity, cost, and location of potential depleted gas and oil wells that are suitable CO{sub 2} repositories (with the cooperation of the oil and gas industry); (2) conduct research on the feasibility of ocean disposal, with objectives of determining the cost, residence time, and environmental effects for different methods of CO{sub 2} injection; (3) perform an in-depth survey of knowledge concerning the feasibility of using deep, confined aquifers for disposal and, if feasible, identify potential disposal locations (with the cooperation of the oil and gas industry); (4) evaluate, on a common basis, system and design alternatives for integration of CO{sub 2} capture systems with emerging and advanced technologies for power generation; and prepare a conceptual design, an analysis of barrier issues, and a preliminary cost estimate for pipeline networks necessary to transport a significant portion of the CO{sub 2} to potentially feasible disposal locations.

  17. Perspectives in the use of carbon dioxide

    Directory of Open Access Journals (Sweden)

    Aresta Michele

    1999-01-01

    Full Text Available The mitigation of carbon dioxide is one of the scientific and technological challenges of the 2000s. Among the technologies that are under assessment, the recovery of carbon dioxide from power plants or industrial flue gases plays a strategic role. Recovered carbon dioxide can be either disposed in natural fields or used. The availability of large amounts of carbon dioxide may open new routes to its utilisation in biological, chemical and innovative technological processes. In this paper, the potential of carbon dioxide utilisation in the short-, medium-term is reviewed.

  18. Carbon sequestration by mangrove forest: One approach for managing carbon dioxide emission from coal-based power plant

    Science.gov (United States)

    Ray, Raghab; Jana, Tapan Kumar

    2017-12-01

    Mangroves are known as natural carbon sinks, taking CO2 out of the atmosphere and store it in their biomass for many years. This study aimed to investigate the capacity of world's largest mangrove, the Sundarbans (Indian part) to sequester anthropogenic CO2 emitted from the proximate coal-based thermal power plant in Kolaghat (∼100 km away from mangrove site). Study also includes Kolkata, one of the largest metropolises of India (∼150 km away from mangrove site) for comparing micrometeorological parameters, biosphere-atmosphere CO2 exchange fluxes and atmospheric pollutants between three distinct environments: mangrove-power plant-metropolis. Hourly sampling of atmospheric CO2 in all three sites (late December 2011 and early January 2012) revealed that CO2 concentrations and emission fluxes were maximum around the power plant (360-621 ppmv, 5.6-56.7 mg m-2s-1 respectively) followed by the metropolis (383-459 ppmv, 3.8-20.4 mg m-2s-1 respectively) and mangroves (277-408 ppmv, -8.9-11.4 mg m-2s-1, respectively). Monthly coal consumption rates (41-57, in 104 ton month-1) were converted to CO2 suggesting that 2.83 Tg C was added to the atmosphere in 2011 for the generation of 7469732 MW energy from the power plant. Indian Sundarbans (4264 km2) sequestered total of 2.79 Tg C which was 0.64% of the annual fossil fuel emission from India in the same time period. Based on these data from 2010 to 2011, it is calculated that about 4328 km2 mangrove forest coverage is needed to sequester all CO2 emitted from the Kolaghat power plant.

  19. Recuperative supercritical carbon dioxide cycle

    Science.gov (United States)

    Sonwane, Chandrashekhar; Sprouse, Kenneth M; Subbaraman, Ganesan; O'Connor, George M; Johnson, Gregory A

    2014-11-18

    A power plant includes a closed loop, supercritical carbon dioxide system (CLS-CO.sub.2 system). The CLS-CO.sub.2 system includes a turbine-generator and a high temperature recuperator (HTR) that is arranged to receive expanded carbon dioxide from the turbine-generator. The HTR includes a plurality of heat exchangers that define respective heat exchange areas. At least two of the heat exchangers have different heat exchange areas.

  20. Higher capacity, lower carbon dioxide emissions. Idle power compensation in HV lines; Mehr Kapazitaet, weniger Kohlendioxid. Blindleistungskompensation bei Hochspannungsleitungen

    Energy Technology Data Exchange (ETDEWEB)

    Auer, Jan-Hendrik von [Alstom Grid GmbH, Berlin (Germany). Team Leistungselektronik und Kompensationsanlagen

    2012-07-01

    Even today, many HP lines have reached their limits. It is therefore highly urgent to find measures for optimum utilization of the available overhead transmssion capacities, e.g. by idle power compensation. Together with a filter for harmonics reduction, this will ensure higher grid stability and enhance transport capacities while reducing transport losses, thus saving money and reducing CO{sub 2} emissions. (orig./AKB)

  1. Highly Reversible Lithium-ions Storage of Molybdenum Dioxide Nanoplates for High Power Lithium-ion Batteries.

    Science.gov (United States)

    Liu, Xiaolin; Yang, Jun; Hou, Wenhua; Wang, Jiulin; Nuli, Yanna

    2015-08-24

    Herein, MoO2 nanoplates have been facilely prepared through a hydrothermal process by using MoO3 microbelts as the intercalation host. The obtained MoO2 nanoplates manifest excellent electrochemical properties when the discharge cutoff voltage is simply set at 1.0 V to preclude the occurrence of conversion reactions. Its initial reversible capacity reaches 251 mAh g(-1), which is larger than that of Li4Ti5O12 , at a current rate of 0.2 C. The average capacity decay is only 0.0465 mAh g(-1) per cycle, with a coulombic efficiency of 99.5% (from the 50th cycle onward) for 2000 cycles at 1 C. Moreover, this MoO2 electrode demonstrates an outstanding high power performance. When the current rate is increased from 0.2 to 50 C, about 54% of the capacity is retained. The superior electrochemical performance can be attributed to the metallic conductivity of MoO2, short Li(+) diffusion distance in the nanoplates, and reversible crystalline phase conversion of the addition-type reaction of MoO2. The prepared MoO2 nanoplates may hopefully replace their currently used analogues, such as Li4Ti5O12 , in high power lithium-ion batteries. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Low Cost, High Capacity Regenerable Sorbent for Carbon Dioxide Capture from Existing Coal-fired Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Alptekin, Gokhan [TDA Research, Inc., Wheat Ridge, CO (United States); Jayaraman, Ambalavanan [TDA Research, Inc., Wheat Ridge, CO (United States); Dietz, Steven [TDA Research, Inc., Wheat Ridge, CO (United States)

    2016-03-03

    In this project TDA Research, Inc (TDA) has developed a new post combustion carbon capture technology based on a vacuum swing adsorption system that uses a steam purge and demonstrated its technical feasibility and economic viability in laboratory-scale tests and tests in actual coal derived flue gas. TDA uses an advanced physical adsorbent to selectively remove CO2 from the flue gas. The sorbent exhibits a much higher affinity for CO2 than N2, H2O or O2, enabling effective CO2 separation from the flue gas. We also carried out a detailed process design and analysis of the new system as part of both sub-critical and super-critical pulverized coal fired power plants. The new technology uses a low cost, high capacity adsorbent that selectively removes CO2 in the presence of moisture at the flue gas temperature without a need for significant cooling of the flue gas or moisture removal. The sorbent is based on a TDA proprietary mesoporous carbon that consists of surface functionalized groups that remove CO2 via physical adsorption. The high surface area and favorable porosity of the sorbent also provides a unique platform to introduce additional functionality, such as active groups to remove trace metals (e.g., Hg, As). In collaboration with the Advanced Power and Energy Program of the University of California, Irvine (UCI), TDA developed system simulation models using Aspen PlusTM simulation software to assess the economic viability of TDA’s VSA-based post-combustion carbon capture technology. The levelized cost of electricity including the TS&M costs for CO2 is calculated as $116.71/MWh and $113.76/MWh for TDA system integrated with sub-critical and super-critical pulverized coal fired power plants; much lower than the $153.03/MWhand $147.44/MWh calculated for the corresponding amine based systems. The cost of CO2 captured for TDA’s VSA based system is $38

  3. A case study of the relative effects of power plant nitrogen oxides and sulfur dioxide emission reductions on atmospheric nitrogen deposition.

    Science.gov (United States)

    Vijayaraghavan, Krish; Seigneur, Christian; Bronson, Rochelle; Chen, Shu-Yun; Karamchandani, Prakash; Walters, Justin T; Jansen, John J; Brandmeyer, Jo Ellen; Knipping, Eladio M

    2010-03-01

    The contrasting effects of point source nitrogen oxides (NOx) and sulfur dioxide (SO2) air emission reductions on regional atmospheric nitrogen deposition are analyzed for the case study of a coal-fired power plant in the southeastern United States. The effect of potential emission reductions at the plant on nitrogen deposition to Escambia Bay and its watershed on the Florida-Alabama border is simulated using the three-dimensional Eulerian Community Multiscale Air Quality (CMAQ) model. A method to quantify the relative and individual effects of NOx versus SO2 controls on nitrogen deposition using air quality modeling results obtained from the simultaneous application of NOx and SO2 emission controls is presented and discussed using the results from CMAQ simulations conducted with NOx-only and SO2-only emission reductions; the method applies only to cases in which ambient inorganic nitrate is present mostly in the gas phase; that is, in the form of gaseous nitric acid (HNO3). In such instances, the individual effects of NOx and SO2 controls on nitrogen deposition can be approximated by the effects of combined NOx + SO2 controls on the deposition of NOy, (the sum of oxidized nitrogen species) and reduced nitrogen species (NHx), respectively. The benefit of controls at the plant in terms of the decrease in nitrogen deposition to Escambia Bay and watershed is less than 6% of the overall benefit due to regional Clean Air Interstate Rule (CAIR) controls.

  4. High power density supercapacitors based on the carbon dioxide activated D-glucose derived carbon electrodes and 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid

    Science.gov (United States)

    Tooming, T.; Thomberg, T.; Kurig, H.; Jänes, A.; Lust, E.

    2015-04-01

    The electrochemical impedance spectroscopy, cyclic voltammetry, constant current charge/discharge and the constant power discharge methods have been applied to establish the electrochemical characteristics of the electrical double-layer capacitor (EDLC) consisting of the 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) ionic liquid and microporous carbon electrodes. Microporous carbon material used for preparation of electrodes (GDAC - glucose derived activated carbon), has been synthesised from D-(+)-glucose by the hydrothermal carbonization method, including subsequent pyrolysis, carbon dioxide activation and surface cleaning step with hydrogen. The Brunauer-Emmett-Teller specific surface area (SBET = 1540 m2 g-1), specific surface area calculated using the non-local density functional theory in conjunction with stable adsorption integral equation using splines (SAIEUS) model SSAIEUS = 1820 m2 g-1, micropore surface area (Smicro = 1535 m2 g-1), total pore volume (Vtot = 0.695 cm3 g-1) and the pore size distribution were obtained from the N2 sorption data. The SBET, Smicro and Vtot values have been correlated with the electrochemical characteristics strongly dependent on the carbon activation conditions applied for EDLCs. Wide region of ideal polarizability (ΔV ≤ 3.2 V), very short charging/discharging time constant (2.7 s), and high specific series capacitance (158 F g-1) have been calculated for the optimized carbon material GDAC-10h (activation of GDAC with CO2 during 10 h) in EMImBF4 demonstrating that this system can be used for completing the EDLC with high energy- and power densities.

  5. Reducing Carbon Dioxide Emissions from the EU Power and Industry Sectors. An assessment of key technologies and measures

    Energy Technology Data Exchange (ETDEWEB)

    Rootzen, Johan

    2012-11-01

    In February 2011, the European Council reconfirmed the goal of reducing EU greenhouse gas emissions by at least 80 % by 2050, as compared to the levels in 1990. The power and industrial sectors currently account for almost half of the total GHG emissions in the EU. The overall objective of the work presented in this thesis is to provide a technology-based perspective on the feasibility of significant reductions in CO{sub 2} emissions in the EU power and industrial sectors, with the emphasis on expected turnover in the capital stock of the existing infrastructure. Three sectors of industry are included: petroleum refining; iron and steel production; and cement manufacturing. The analysis is based on a thorough description and characterization of the current industry infrastructure and of the key mitigation technologies and measures in each sector. The analysis comprises investigations of how specific factors, such as the age structure of the capital stock, technology and fuel mix, and spatial distribution of the plant stock, contribute to facilitating or hindering the shift towards less-emission-intensive production processes. The results presented here are the synthesis of the results described in the following three papers: Paper I investigates the potential for CCS in industrial applications in the EU by considering branch- and plant-specific conditions; Paper II assesses strategies for CO{sub 2} abatement in the European petroleum refining industry; and Paper III explores in a scenario analysis the limits for CO{sub 2} emission abatement within current production processes in the power and industrial sectors. Together, the three papers provide a comprehensive assessment of the roles of technologies and measures that are commercially available today, as well as those of emerging technologies that are still in their early phases of development. The results presented in Paper III show that the EU goal for emissions reductions in the sectors covered by the EU ETS, i

  6. Detailed Theoretical Characterization of a Transcritical CO2 Direct Expansion Ground Source Heat Pump Water Heater

    Directory of Open Access Journals (Sweden)

    Parham Eslami-Nejad

    2018-02-01

    Full Text Available A new avenue in modern heat pump technology is related to the use of natural refrigerants such as carbon dioxide (CO2. The use of CO2 in direct expansion ground source heat pumps (DX-GSHP has also gained significant interest as it offers opportunities for cost reduction of the ground loop, albeit some challenges remain in their development, design and use. To address these challenges and to characterize CO2-DX-GSHP performance for water heating applications, a detailed theoretical model and a fully-instrumented test apparatus was developed and built at CanmetENERGY Research Laboratory. The theoretical model was validated against a set of experimental results and adopted to investigate the performance of the system over a wide operating range. Validation results showed that the model predicts the experimental results within the measurement uncertainty. A detailed system performance analysis was also performed using the theoretical model to understand the system behavior and explore the actions required for performance improvement in future installations. The results of the analysis showed that improper design and control of some components, such as the gas cooler and ground heat exchanger can degrade the system performance by up to 25%, and the heat pump heating capacity by 7.5%.

  7. Analysis of an integrated cryogenic air separation unit, oxy-combustion carbon dioxide power cycle and liquefied natural gas regasification process by exergoeconomic method

    International Nuclear Information System (INIS)

    Mehrpooya, Mehdi; Zonouz, Masood Jalali

    2017-01-01

    Highlights: • Exergoeconomic analyses is done on an integrated cryogenic air separation unit. • Liquefied natural gas cold energy is used in the process. • The main multi stream heat exchanger is the worst device based on the results. - Abstract: Exergoeconomic and sensitivity analyses are performed on the integrated cryogenic air separation unit, oxy-combustion Carbon dioxide power cycle and liquefied natural gas regasification process. Exergy destruction, exergy efficiency, cost rate of exergy destruction, cost rate of capital investment and operating and maintenance, exergoeconomic factor and relative cost difference have been calculated for the major components of the process. The exergy efficiency of the process is around 67.1% and after mixers, tees, tank and expansion valves the multi-stream heat exchanger H-3 have the best exergy efficiency among all process components. Total exergy destruction rate of the process is 1.93 × 10"7 kW. Results of exergoeconomic analysis demonstrates that maximum exergy destruction and capital investment operating and maintenance cost rate are related to the multi-stream heat exchanger H-1 and pump P-1 with the values of 335,144 ($/h) and 12,838 ($/h), respectively. In the sensitivity analysis section the effects of the varying economic parameters, such as interest rate and plant life time are investigated on the trend of the capital investment operating and maintenance cost rate of the major components of the process and in another cases the effect of the gas turbine isentropic efficiency on the exergy and exergoeconomic parameters are studied.

  8. Carbon Dioxide Removal via Passive Thermal Approaches

    Science.gov (United States)

    Lawson, Michael; Hanford, Anthony; Conger, Bruce; Anderson, Molly

    2011-01-01

    A paper describes a regenerable approach to separate carbon dioxide from other cabin gases by means of cooling until the carbon dioxide forms carbon dioxide ice on the walls of the physical device. Currently, NASA space vehicles remove carbon dioxide by reaction with lithium hydroxide (LiOH) or by adsorption to an amine, a zeolite, or other sorbent. Use of lithium hydroxide, though reliable and well-understood, requires significant mass for all but the shortest missions in the form of lithium hydroxide pellets, because the reaction of carbon dioxide with lithium hydroxide is essentially irreversible. This approach is regenerable, uses less power than other historical approaches, and it is almost entirely passive, so it is more economical to operate and potentially maintenance- free for long-duration missions. In carbon dioxide removal mode, this approach passes a bone-dry stream of crew cabin atmospheric gas through a metal channel in thermal contact with a radiator. The radiator is pointed to reject thermal loads only to space. Within the channel, the working stream is cooled to the sublimation temperature of carbon dioxide at the prevailing cabin pressure, leading to formation of carbon dioxide ice on the channel walls. After a prescribed time or accumulation of carbon dioxide ice, for regeneration of the device, the channel is closed off from the crew cabin and the carbon dioxide ice is sublimed and either vented to the environment or accumulated for recovery of oxygen in a fully regenerative life support system.

  9. Absorption of carbon dioxide in waste tanks

    International Nuclear Information System (INIS)

    Hobbs, D.T.

    1987-01-01

    Air flow rates and carbon dioxide concentrations of air entering and exiting eight H-Area waste tanks were monitored for a period of one year. The average instanteous concentration of carbon dioxide in air is within the range reported offsite, and therefore is not affect by operation of the coal-fired power plant adjacent to the tank farm. Waste solutions in each of the tanks were observed to be continuously absorbing carbon dioxide. The rate of absorption of carbon dioxide decreased linearly with the pH of the solution. Personnel exposure associated with the routine sampling and analysis of radioactive wastes stored at SRP to determine the levels of corrosion inhibitors in solution could be reduced by monitoring the absorption of carbon dioxide and using the relationship between pH and carbon dioxide absorption to determine the free hydroxide concentration in solution

  10. Economic performances optimization of the transcritical Rankine cycle systems in geothermal application

    International Nuclear Information System (INIS)

    Yang, Min-Hsiung; Yeh, Rong-Hua

    2015-01-01

    Highlights: • The optimal economic performance of the TRC system are investigated. • In economic evaluations, R125 performs the most satisfactorily, followed by R41 and CO 2 . • The TRC system with CO 2 has the largest averaged temperature difference. • Economic optimized pressures are always lower than thermodynamic optimized operating pressures. - Abstract: The aim of this study is to investigate the economic optimization of a TRC system for the application of geothermal energy. An economic parameter of net power output index, which is the ratio of net power output to the total cost, is applied to optimize the TRC system using CO 2 , R41 and R125 as working fluids. The maximum net power output index and the corresponding optimal operating pressures are obtained and evaluated for the TRC system. Furthermore, the analyses of the corresponding averaged temperature differences in the heat exchangers on the optimal economic performances of the TRC system are carried out. The effects of geothermal temperatures on the thermodynamic and economic optimizations are also revealed. In both optimal economic and thermodynamic evaluations, R125 performs the most satisfactorily, followed by R41 and CO 2 in the TRC system. In addition, the TRC system operated with CO 2 has the largest averaged temperature difference in the heat exchangers and thus has potential in future application for lower-temperature heat resources. The highest working pressures obtained from economic optimization are always lower than those from thermodynamic optimization for CO 2 , R41, and R125 in the TRC system

  11. Numerical model for thermoeconomic diagnosis in commercial transcritical/subcritical booster refrigeration systems

    DEFF Research Database (Denmark)

    Ommen, Torben; Elmegaard, Brian

    2012-01-01

    cycle supplying refrigerant for evaporators in both chilled and frozen display cases. In the paper, thermoeconomic theory is used to establish the cost of cooling at each individual temperature level based on operating costs.With a high amount of operating systems, faulty operation becomes an economic......, and environmental, interest. A general solution for evaluation of these systems is considered, with the objective to reduce cost and power consumption of malfunctioning equipment in operation. An analysis of the use of thermoeconomic diagnosis methods is required, as these methods may prove applicable...

  12. The application of an isotopic ratio technique to a study of the atmospheric oxidation of sulfur dioxide in the plume from a coal fired power plant

    International Nuclear Information System (INIS)

    Newman, L.; Forrest, J.; Manowitz, B.

    1975-01-01

    The extent of oxidation of sulfur dioxide to sulfate in the plume of a coal fired plant has been studied by using sampling with a single engine aircraft. A technique employing isotopic ratio measurements was utilized in conjunction with simultaneous concentration measurements of sulfur dioxide and sulfate. The use of sulfur hexafluroide as a conservative tracer was explored. The heterogeneous mechanism postulated in an oil fired plume study appears to pertain to the coal fired plume. However, the extent of oxidation seldom exceeded 5% and is limited by the relatively low particulate content of the coal fired plume. Evidence is presented for the apparent dropping out of sulfate from the plume. Implications pertaining to the ambient oxidation of sulfur dioxide are presented. (author)

  13. Green methanol from hydrogen and carbon dioxide using geothermal energy and/or hydro power in Iceland or excess renewable electricity in Germany

    NARCIS (Netherlands)

    Kauw, Marco; Benders, Reinerus; Visser, Cindy

    2015-01-01

    The synthesis of green methanol from hydrogen and carbon dioxide can contribute to mitigation of greenhouse gasses. This methanol can be utilized as either a transport fuel or as an energy carrier for electricity storage. It is preferable to use inexpensive, reliable and renewable energy sources to

  14. 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.

  15. Corrigendum to "Sinusoidal potential cycling operation of a direct ethanol fuel cell to improving carbon dioxide yields" [J. Power Sources 268 (5 December 2014) 439-442

    Science.gov (United States)

    Majidi, Pasha; Pickup, Peter G.

    2016-09-01

    The authors regret that Equation (5) is incorrect and has resulted in errors in Fig. 4 and the efficiencies stated on p. 442. The corrected equation, figure and text are presented below. In addition, the title should be 'Sinusoidal potential cycling operation of a direct ethanol fuel cell to improve carbon dioxide yields', and the reversible cell potential quoted on p. 441 should be 1.14 V. The authors would like to apologise for any inconvenience caused.

  16. Thermodynamic analysis of a compressed carbon dioxide energy storage system using two saline aquifers at different depths as storage reservoirs

    International Nuclear Information System (INIS)

    Liu, Hui; He, Qing; Borgia, Andrea; Pan, Lehua; Oldenburg, Curtis M.

    2016-01-01

    Highlights: • A compressed CO_2 energy storage system using two storage reservoirs is presented. • Compressed CO_2 energy storage density is higher than that of CAES. • The effects of storage reservoir pressure on the system performance are studied. - Abstract: Compressed air energy storage (CAES) is one of the leading large-scale energy storage technologies. However, low thermal efficiency and low energy storage density restrict its application. To improve the energy storage density, we propose a two-reservoir compressed CO_2 energy storage system. We present here thermodynamic and parametric analyses of the performance of an idealized two-reservoir CO_2 energy storage system under supercritical and transcritical conditions using a steady-state mathematical model. Results show that the transcritical compressed CO_2 energy storage system has higher round-trip efficiency and exergy efficiency, and larger energy storage density than the supercritical compressed CO_2 energy storage. However, the configuration of supercritical compressed CO_2 energy storage is simpler, and the energy storage densities of the two systems are both higher than that of CAES, which is advantageous in terms of storage volume for a given power rating.

  17. Uranium dioxide electrolysis

    Science.gov (United States)

    Willit, James L [Batavia, IL; Ackerman, John P [Prescott, AZ; Williamson, Mark A [Naperville, IL

    2009-12-29

    This is a single stage process for treating spent nuclear fuel from light water reactors. The spent nuclear fuel, uranium oxide, UO.sub.2, is added to a solution of UCl.sub.4 dissolved in molten LiCl. A carbon anode and a metallic cathode is positioned in the molten salt bath. A power source is connected to the electrodes and a voltage greater than or equal to 1.3 volts is applied to the bath. At the anode, the carbon is oxidized to form carbon dioxide and uranium chloride. At the cathode, uranium is electroplated. The uranium chloride at the cathode reacts with more uranium oxide to continue the reaction. The process may also be used with other transuranic oxides and rare earth metal oxides.

  18. Supercritical carbon dioxide: a solvent like no other

    Directory of Open Access Journals (Sweden)

    Jocelyn Peach

    2014-08-01

    Full Text Available Supercritical carbon dioxide (scCO2 could be one aspect of a significant and necessary movement towards green chemistry, being a potential replacement for volatile organic compounds (VOCs. Unfortunately, carbon dioxide has a notoriously poor solubilising power and is famously difficult to handle. This review examines attempts and breakthroughs in enhancing the physicochemical properties of carbon dioxide, focusing primarily on factors that impact solubility of polar and ionic species and attempts to enhance scCO2 viscosity.

  19. Ideal Point Design and Operation of CO2-Based Transcritical Rankine Cycle (CTRC System Based on High Utilization of Engine’s Waste Heats

    Directory of Open Access Journals (Sweden)

    Lingfeng Shi

    2017-10-01

    Full Text Available This research conducted a study specially to systematically analyze combined recovery of exhaust gas and engine coolant and related influence mechanism, including a detailed theoretical study and an assistant experimental study. In this research, CO2-based transcritical Rankine cycle (CTRC was used for fully combining the wastes heats. The main objective of theoretical research was to search an ‘ideal point’ of the recovery system and related influence mechanism, which was defined as operating condition of complete recovery of two waste heats. The theoretical methodology of this study could also provide a design reference for effective combined recovery of two or multiple waste heats in other fields. Based on a kW-class preheated CTRC prototype that was designed by the ‘ideal point’ method, an experimental study was conducted to verify combined utilization degree of two engine waste heats by the CTRC system. The operating results showed that the prototype can gain 44.4–49.8 kW and 22.7–26.7 kW heat absorption from exhaust gas and engine coolant, respectively. To direct practical operation, an experimental optimization work on the operating process was conducted for complete recovery of engine coolant exactly, which avoided deficient or excessive recovery.

  20. Carbon dioxide as chemical feedstock

    National Research Council Canada - National Science Library

    Aresta, M

    2010-01-01

    ... Dioxide as an Inert Solvent for Chemical Syntheses 15 Alessandro Galia and Giuseppe Filardo Introduction 15 Dense Carbon Dioxide as Solvent Medium for Chemical Processes 15 Enzymatic Catalysis in Dense Carbon Dioxide 18 Other Reactions in Dense Carbon Dioxide 19 Polymer Synthesis in Supercritical Carbon Dioxide 20 Chain Polymerizations: Synt...

  1. Method and aparatus for flue gas cleaning by separation and liquefaction of sulfur dioxide and carbon dioxide

    International Nuclear Information System (INIS)

    Abdelmalek, F.T.

    1992-01-01

    This patent describes a method for recovering sulfur dioxide, carbon dioxide, and cleaning flue gases emitted from power plants. It comprises: electronically treating the flue gases to neutralize its electrostatic charges and to enhance the coagulation of its molecules and particles; exchanging sensible and latent heat of the neutralized flue gases to lower its temperature down to a temperature approaching the ambient temperature while recovering its separating the flue gas in a first stage; cooling the separated enriched carbon dioxide gas fraction, after each separation stage, while removing its vapor condensate, then compressing the enriched carbon dioxide gas fraction and simultaneously cooling the compressed gas to liquefy the sulfur dioxide gas then; allowing the sulfur dioxide gas to condense, and continuously removing the liquefied sulfur dioxide; compressing he desulfurized enriched carbon dioxide fraction to further increase its pressure, and simultaneously cooling he compressed gas to liquefy the carbon dioxide gas, then; allowing the carbon dioxide gas to condense and continuously removing the liquefied carbon dioxide; allowing the light components of the flue gas to be released in a cooling tower discharge plume

  2. Classification of titanium dioxide

    International Nuclear Information System (INIS)

    Macias B, L.R.; Garcia C, R.M.; Maya M, M.E.; Ita T, A. De; Palacios G, J.

    2002-01-01

    In this work the X-ray diffraction (XRD), Scanning Electron Microscopy (Sem) and the X-ray Dispersive Energy Spectroscopy techniques are used with the purpose to achieve a complete identification of phases and mixture of phases of a crystalline material as titanium dioxide. The problem for solving consists of being able to distinguish a sample of titanium dioxide being different than a titanium dioxide pigment. A standard sample of titanium dioxide with NIST certificate is used, which indicates a purity of 99.74% for the TiO 2 . The following way is recommended to proceed: a)To make an analysis by means of X-ray diffraction technique to the sample of titanium dioxide pigment and on the standard of titanium dioxide waiting not find differences. b) To make a chemical analysis by the X-ray Dispersive Energy Spectroscopy via in a microscope, taking advantage of the high vacuum since it is oxygen which is analysed and if it is concluded that the aluminium oxide appears in a greater proportion to 1% it is established that is a titanium dioxide pigment, but if it is lesser then it will be only titanium dioxide. This type of analysis is an application of the nuclear techniques useful for the tariff classification of merchandise which is considered as of difficult recognition. (Author)

  3. A multi-period optimization model for planning of China's power sector with consideration of carbon dioxide mitigation—The importance of continuous and stable carbon mitigation policy

    International Nuclear Information System (INIS)

    Zhang, Dongjie; Liu, Pei; Ma, Linwei; LI, Zheng

    2013-01-01

    A great challenge China's power sector faces is to mitigate its carbon emissions whilst satisfying the ever-increasing power demand. Optimal planning of the power sector with consideration of carbon mitigation for a long-term future remains a complex task, involving many technical alternatives and an infinite number of possible plants installations, retrofitting, and decommissioning over the planning horizon. Previously the authors built a multi-period optimization model for the planning of China's power sector during 2010–2050. Based on that model, this paper executed calculations on the optimal pathways of China's power sector with two typical decision-making modes, which are based on “full-information” and “limited-information” hypothesis, and analyzed the impacts on the optimal planning results by two typical types of carbon tax policies including a “continuous and stable” one and a “loose first and tight later” one. The results showed that making carbon tax policy for long-term future, and improving the continuity and stability in policy execution can effectively help reduce the accumulated total carbon emissions, and also the cost for carbon mitigation of the power sector. The conclusion of this study is of great significance for the policy makers to make carbon mitigation policies in China and other countries as well. - Highlights: • A multi-stage optimization model for planning the power sector is applied as basis. • Difference of ideal and actual decision making processes are proposed and analyzed. • A “continuous and stable” policy and a “loose first and tight later” one are designed. • 4 policy scenarios are studied applying the optimal planning model and compared. • The importance of “continuous and stable” policy for long term is well demonstrated

  4. Characterization, antibacterial, total antioxidant, scavenging, reducing power and ion chelating activities of green synthesized silver, copper and titanium dioxide nanoparticles using Artemisia haussknechtii leaf extract.

    Science.gov (United States)

    Alavi, Mehran; Karimi, Naser

    2017-12-12

    Recently, major problem related to pathogenic bacteria is augmentation of antibiotic resistance which has been changed treatment and recovery of millions of infectious patients. The present study reports an eco-friendly, rapid and easy method for synthesis of silver (Ag), copper (Cu) and titanium dioxide (TiO 2 ) nanoparticles (NPs) using Artemisia haussknechtii leaf aqueous extract with antibacterial activities against multi-drug resistance (MDR) bacteria species. Three different concentrations (0.001, 0.01 and 0.1 M) of AgNO 3 , CuSO 4 and TiO (OH) 2 were investigated for obtaining optimum NPs green synthesis. Total phenolic content, total flavonoid content of leaf extract and total antioxidant activity (DPPH) assay were determined as radical scavenging methods. UV-Visible spectroscopy, Fourier transform infrared spectroscopy analysis, X-ray diffraction, energy dispersive X-ray spectroscopy, field emission scanning electron microscope and atomic force microscopy (AFM) were used due to NPs characterization. The size average of the Ag, Cu and TiO 2 NPs obtained were respectively 10.69 ± 5.55, 35.36 ± 44.4 and 92.58 ± 56.98 nm. In the case of antibacterial assay, disc diffusion assay, minimum inhibitory concentration, minimum bactericidal concentration, bacterial growth and morphology of four MDR species Staphylococcus aureus ATCC 43300, Staphylococcus epidermidis ATCC 12258, Serratia marcescens ATTC13880 and Escherichia coli ATCC 25922 were evaluated. Results of this study demonstrated that A. haussknechtii leaf extract with various groups of phytochemicals such as phenols and flavonoids had suitable ability in green synthesis of Ag, Cu and TiO 2 NPs. Also, Ag and Cu NPs had more antibacterial activities compared to TiO 2 NPs.

  5. Molecular dynamics study of combustion reactions in supercritical environment. Part 1: Carbon dioxide and water force field parameters refitting and critical isotherms of binary mixtures

    International Nuclear Information System (INIS)

    Masunov, Artem E.; Atlanov, Arseniy Alekseyevich; Vasu, Subith S.

    2016-01-01

    Oxy-fuel combustion process is expected to drastically increase the energy efficiency and enable easy carbon sequestration. In this technology the combustion products (carbon dioxide and water) are used to control the temperature and nitrogen is excluded from the combustion chamber, so that nitrogen oxide pollutants do not form. Therefore, in oxycombustion the carbon dioxide and water are present in large concentrations in their transcritical state, and may play an important role in kinetics. The computational chemistry methods may assist in understanding these effects, and Molecular Dynamics with ReaxFF force field seem to be a suitable tool for such a study. Here we investigate applicability of the ReaxFF to describe the critical phenomena in carbon dioxide and water and find that several nonbonding parameters need adjustment. We report the new parameter set, capable to reproduce the critical temperatures and pressures. Furthermore, the critical isotherms of CO 2 /H 2 O binary mixtures are computationally studied here for the first time and their critical parameters are reported.

  6. Huge enhancement of energy storage capacity and power density of supercapacitors based on the carbon dioxide activated microporous SiC-CDC

    International Nuclear Information System (INIS)

    Tee, Ester; Tallo, Indrek; Kurig, Heisi; Thomberg, Thomas; Jänes, Alar; Lust, Enn

    2015-01-01

    Nanostructured carbide-derived carbons (CDC) were synthesized from SiC powders (SiC-CDC) via gas phase chlorination within the temperature range from 1000 °C to 1100 °C. Thereafter the CDCs were additionally activated by CO 2 treatment method, resulting in nearly two-fold increase in specific surface area. The results of X-ray diffraction, high-resolution transmission electron microscopy and Raman spectroscopy showed that the synthesized CDC materials are mainly amorphous, however containing small graphitic crystallites. The low-temperature N 2 sorption experiments were performed and the specific micropore surface areas from 1100 m 2 g −1 up to 2270 m 2 g −1 were obtained, depending on the extent of CO 2 activation. The energy and power density characteristics of the supercapacitors based on 1 M (C 2 H 5 ) 3 CH 3 NBF 4 solution in acetonitrile and SiC-CDC as an electrode material were investigated using the cyclic voltammetry, electrochemical impedance spectroscopy, galvanostatic charge/discharge and constant power discharge methods. The electrochemical data indicated two-times increase in specific capacitance. Most importantly, the activation of SiC-CDC with CO 2 significantly increases the performance (energy density, power density, etc.) of the supercapacitors especially at higher potential scan rates and at higher power loads

  7. A decomposition analysis of the driving factors of CO_2 (Carbon dioxide) emissions from the power sector in the European Union countries

    International Nuclear Information System (INIS)

    Karmellos, M.; Kopidou, D.; Diakoulaki, D.

    2016-01-01

    The scope of this paper is to investigate the driving factors of CO_2 emissions from electricity generation in all European Union countries (EU-28) during the period 2000–2012. Particular emphasis is placed on the assessment of any potential association between the examined driving factors and major climate and energy policies implemented during the examined period. In addition, the analysis distinguishes two subperiods, namely 2000–2007 and 2007–2012 in order to detect the impact of the economic crisis on each distinct driving factor and, consequently, on the total level of CO_2 emissions from the power sector. The model developed to analyse the changes in CO_2 emissions from the power sector across EU-28, is based on LMDI-I method and takes into account five driving factors: level of activity, electricity intensity, electricity trade, efficiency of electricity generation and fuel mix. The obtained results show that in times of economic growth the main factor counterbalancing the activity effect was in most countries the decreasing electricity intensity, while the contribution of all other factors becomes apparent later, despite the economic crisis and in view of the Kyoto targets. - Highlights: • LMDI is used to identify driving forces of CO_2 emissions from EU's power sector. • Declining electricity intensity was the main restrictive factor before 2007. • Fuel shifts contributed to emissions fall mostly after 2007, despite the crisis. • Trade effect is notable and indicates growing carbon leakage in the power sector.

  8. 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

  9. Conductive polymers for carbon dioxide sensing

    NARCIS (Netherlands)

    Doan, T.C.D.

    2012-01-01

    Augmented levels of carbon dioxide (CO2) in greenhouses stimulate plant growth through photosynthesis. Wireless sensor networks monitoring CO2 levels in greenhouses covering large areas require preferably low power sensors to minimize energy consumption. Therefore, the main

  10. Numerical analysis of air-foil shaped fin performance in printed circuit heat exchanger in a supercritical carbon dioxide power cycle

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Ho [Department of Mechanical Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Kwon, Jin Gyu [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Yoon, Sung Ho [Korea Institute of Nuclear Nonproliferation and Control, Daejeon 305-348 (Korea, Republic of); Park, Hyun Sun, E-mail: hejsunny@postech.ac.kr [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Kim, Moo Hwan [Korea Institute of Nuclear Safety, Daejeon 305-338 (Korea, Republic of); Cha, Jae Eun [Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of)

    2015-07-15

    Highlights: • Staggered arrangement affects the pressure drop but does not significantly affect to the heat transfer. • The total pressure drop is reduced, but the amount of acceleration pressure drop increases while that of frictional pressure drop decreases as the horizontal number increases. • For the vertical number, the total pressure drop decreases more largely than the horizontal number. • The objective function shows that the fully staggered arrangement shows best performance. - Abstract: One of the key issues of the PCHE technology in the supercritical CO{sub 2} Brayton cycle is to achieve an efficient and compact designs to be able to enhance heat transfer and reduce pressure drop. The issue is challenging due to the complex configuration of micro-channels in the PCHE. In this study, an innovative micro-channel equipped with an array of airfoil fins is analyzed to evaluate its performance. In so doing, sensitivity analysis with various design parameters is performed to configure the optimal arrangement of airfoil fins by using CFD analysis for Supercritical Carbon dioxide Integral Experimental Loop (SCIEL) in Korean Atomic Energy Research Institute (KAERI). Dominant geometric parameters of the fin arrangement that affects to the thermal and hydraulic performances are the horizontal, vertical and staggered pitches. ANSYS ICEM CFD and ANSYS CFX are used for the grid generation and the computational calculation. CO{sub 2} properties are used by using REFPROF software database. The inlet temperature of the hot side is 618 K and that of the cold side is 585 K. The reference mass flow rate is set as 1.2 g/s for the vertical number of 2.0, which is the Reynolds number of about 30,000. The mass flow rate changes from 0.4 to 4.8 g/s in order to investigate the Reynolds number effect. The k-ε model is selected as the turbulence model. In conclusions, the results show that the optimal arrangement of airfoil fins can be examined in terms of an objective

  11. Power

    DEFF Research Database (Denmark)

    Elmholdt, Claus Westergård; Fogsgaard, Morten

    2016-01-01

    and creativity suggests that when managers give people the opportunity to gain power and explicate that there is reason to be more creative, people will show a boost in creative behaviour. Moreover, this process works best in unstable power hierarchies, which implies that power is treated as a negotiable....... It is thus a central point that power is not necessarily something that breaks down and represses. On the contrary, an explicit focus on the dynamics of power in relation to creativity can be productive for the organisation. Our main focus is to elaborate the implications of this for practice and theory...

  12. Uranium dioxide. Sintering test

    International Nuclear Information System (INIS)

    Anon.

    Description of a sintering method and of the equipment devoted to uranium dioxide powder caracterization and comparison between different samples. Determination of the curve giving specific volume versus pressure and micrographic examination of a pellet at medium pressure [fr

  13. Slipstream pilot-scale demonstration of a novel amine-based post-combustion technology for carbon dioxide capture from coal-fired power plant flue gas

    Energy Technology Data Exchange (ETDEWEB)

    Krishnamurthy, Krish R. [Linde LLC, Murray Hill, NJ (United States)

    2017-02-03

    Post-combustion CO2 capture (PCC) technology offers flexibility to treat the flue gas from both existing and new coal-fired power plants and can be applied to treat all or a portion of the flue gas. Solvent-based technologies are today the leading option for PCC from commercial coal-fired power plants as they have been applied in large-scale in other applications. Linde and BASF have been working together to develop and further improve a PCC process incorporating BASF’s novel aqueous amine-based solvent technology. This technology offers significant benefits compared to other solvent-based processes as it aims to reduce the regeneration energy requirements using novel solvents that are very stable under the coal-fired power plant feed gas conditions. BASF has developed the desired solvent based on the evaluation of a large number of candidates. In addition, long-term small pilot-scale testing of the BASF solvent has been performed on a lignite-fired flue gas. In coordination with BASF, Linde has evaluated a number of options for capital cost reduction in large engineered systems for solvent-based PCC technology. This report provides a summary of the work performed and results from a project supported by the US DOE (DE-FE0007453) for the pilot-scale demonstration of a Linde-BASF PCC technology using coal-fired power plant flue gas at a 1-1.5 MWe scale in Wilsonville, AL at the National Carbon Capture Center (NCCC). Following a project kick-off meeting in November 2011 and the conclusion of pilot plant design and engineering in February 2013, mechanical completion of the pilot plant was achieved in July 2014, and final commissioning activities were completed to enable start-up of operations in January 2015. Parametric tests were performed from January to December 2015 to determine optimal test conditions and evaluate process performance over a variety of operation parameters. A long-duration 1500-hour continuous test campaign was performed from May to

  14. Reduction of sulphur dioxide emissions by pyrolysis reduction of the burning sulfur of coal, applied in the power station 'Maritsa-East 3'

    International Nuclear Information System (INIS)

    Lyutskanov, L.; Dushanov, D.

    1999-01-01

    A study for applying of the new method for reduction of the sulfur content in solid fuel reported at the Energy Forum '98 has been carried out. The calculations for using this method at the power station 'Maritsa-East 3' were made. The advantages compared to the conventional methods for removing of SO 2 from flue gases are reported. The application of this method reduces the emissions of SO 2 with 83-85%. The heat saved is equal to the heat from 13.8% of the coal. The tar obtained after removing of sulfur can be used as fuel. The expenses for transport and treatment of limestone and of obtained gypsum (needed at the conventional methods for removing the sulfur) are eliminated. The capital investments needed are smaller because of the 25-30 times smaller volume of the equipment for sulfur reduction

  15. A Global Outlook to the Carbon Dioxide Emissions in the World and Emission Factors of the Thermal Power Plants in Turkey

    International Nuclear Information System (INIS)

    Atimtay, Aysel T.

    2003-01-01

    World primary energy demand increases with increases in population and economic development. Within the last 25 yr, the total energy consumption has almost doubled. For the purpose of meeting this demand, fossil energy sources are used and various pollutants are generated. CO 2 is also one of these gases, which cannot be removed like other pollutants, and it causes greenhouse effect and climate change. Reducing the CO 2 emission is very important because of the environmental concerns and regulations, especially the Kyoto Protocol. This paper reviews the estimated world carbon emissions, Turkey's situation in electrical energy production, emission amounts estimated until the year 2020 and emission factors for dust, SO 2 , NO x and CO 2 . The estimated results show that CO 2 emissions from thermal power plants in Turkey will make about 0.66 % of the global CO 2 emissions in 2020

  16. A Novel High-Power Battery-Pseudocapacitor Hybrid Based on Fast Lithium Reactions in Silicon Anode and Titanium Dioxide Cathode Coated on Vertically Aligned Carbon Nanofibers

    International Nuclear Information System (INIS)

    Klankowski, Steven A.; Pandey, Gaind P.; Malek, Gary A.; Wu, Judy; Rojeski, Ronald A.; Li, Jun

    2015-01-01

    Highlights: • A unique battery-supercapacitor hybrid has been demonstrated. • Both Si anode and TiO_2 cathode are fabricated in the form of nanocolumnar shells coated on VACNFs. • Hybrid cells achieve stable charge-discharge cycles in the supercapacitor power regime. - Abstract: An electrochemical cell representing a battery-supercapacitor hybrid is demonstrated with a Si anode and a TiO_2 cathode based on Lithium chemistry. Both materials are fabricated as coaxial shells with an oblique nanocolumnar structure anchored on vertical aligned carbon nanofiber arrays. The Li"+ ion transport and electrical connection is greatly enhanced with such nanoporous core-shell architectures, leading to optimal Li storage properties. The full theoretical capacity of the shell materials has been obtained at normal C-rates (C/1 to C/2) for Si (∼3,000 to 3500 mA h g"−"1) and TiO_2 (∼170 mA h g"−"1) half-cells, respectively, with excellent cycling stability. More importantly, much higher rates (up to 4.7C_S_i for Si and 76C_T_i_O_2 for TiO_2) can be applied at relatively small capacity loss, approaching the properties of supercapacitors. The charge-discharge profiles show battery-supercapacitor hybrid features, which are attributed to the short Li"+ diffusion path across the solid materials and the large pseudocapacitive contribution from fast surface reactions. A full cell containing similar volume of Si and TiO_2 shows a high specific energy (103 W h kg"−"1) at low current rates, comparable to a decent battery, and a remarkable specific power (56,000 W kg"−"1) at high current rates, matching the state-of-the-art supercapacitors.

  17. Nitrogen dioxide exposures inside ice skating rinks.

    Science.gov (United States)

    Brauer, M; Spengler, J D

    1994-01-01

    OBJECTIVES. The common operation of fuel-powered resurfacing equipment in enclosed ice skating rinks has the potential for producing high concentrations of carbon monoxide and nitrogen dioxide. Exposures to these gaseous combustion products may adversely affect the health of those inside the rink. Little information is available on pollutant concentrations under normal operating conditions. METHODS. One-week average nitrogen dioxide concentrations in 70 northeastern US rinks were measured with passive samplers during normal winter season conditions. RESULTS. The median nitrogen dioxide level inside rinks was 180 ppb, more than 10 times higher than the median outdoor concentration. One-week average nitrogen dioxide concentrations above 1000 ppb were measured in 10% of the rinks. CONCLUSIONS. Considering that short-term peak concentrations were likely to have reached two to five times the measured 1-week averages, our results suggest that nitrogen dioxide levels were well above short-term air quality guidelines and constitute a public health concern of considerable magnitude. PMID:8129060

  18. Potassium carbonate scrubber for removing carbon dioxide from flue and product gases of power plant and industrial processes as a robust alternative to amine treatment; Alkalicarbonatwaesche zur Entfernung von Kohlendioxid aus Rauch- und Produktgasen von Kraftwerks- und Industrieprozessen als robuste Alternative zu Aminwaeschen

    Energy Technology Data Exchange (ETDEWEB)

    Berry, Andrew; Erich, Egon; Bathen, Dieter [Institut fuer Energie- und Umwelttechnik e.V. (IUTA), Duisburg (Germany); Telge, Stephan; Fahlenkamp, Hans [Dortmund Univ. (Germany). Lehrstuhl Umwelttechnik; Domels, Hans-Peter; Kesseler, Klaus; Igelbuescher, Andreas [ThyssenKrupp Steel Europe AG, Duisburg (Germany); Schluseman, Ernst [Stadtwerke Duisburg AG, Duisburg (Germany)

    2011-07-01

    When new conventional power plants are constructed and built, it is necessary to reduce carbon dioxide (CO{sub 2}) emissions in order to meet the climate protection targets. The development of possible technologies for capturing CO{sub 2} is the subject of intensive current research efforts. Usually the principle of amine scrubbing, which is a well-known process in petrochemistry, serves as a procedural basis for the separation of CO{sub 2}. However, difficulties occur when transferring this method to power plant conditions. The paper describes the process of potash scrubbing as a possible alternative to CO{sub 2} cleaning of flue gases as well as of process gases. The results of a research project are introduced. Laboratory studies and pilot-scale experiments also embraced the separation of carbon dioxide with a mobile absorption system. (orig.)

  19. Impacts of Combined Cooling, Heating and Power Systems, and Rainwater Harvesting on Water Demand, Carbon Dioxide, and NOx Emissions for Atlanta.

    Science.gov (United States)

    James, Jean-Ann; Sung, Sangwoo; Jeong, Hyunju; Broesicke, Osvaldo A; French, Steven P; Li, Duo; Crittenden, John C

    2018-01-02

    The purpose of this study is to explore the potential water, CO 2 and NO x emission, and cost savings that the deployment of decentralized water and energy technologies within two urban growth scenarios can achieve. We assess the effectiveness of urban growth, technological, and political strategies to reduce these burdens in the 13-county Atlanta metropolitan region. The urban growth between 2005 and 2030 was modeled for a business as usual (BAU) scenario and a more compact growth (MCG) scenario. We considered combined cooling, heating and power (CCHP) systems using microturbines for our decentralized energy technology and rooftop rainwater harvesting and low flow fixtures for the decentralized water technologies. Decentralized water and energy technologies had more of an impact in reducing the CO 2 and NO x emissions and water withdrawal and consumption than an MCG growth scenario (which does not consider energy for transit). Decentralized energy can reduce the CO 2 and NO x emissions by 8% and 63%, respectively. Decentralized energy and water technologies can reduce the water withdrawal and consumption in the MCG scenario by 49% and 50% respectively. Installing CCHP systems on both the existing and new building stocks with a net metering policy could reduce the CO 2 , NO x , and water consumption by 50%, 90%, and 75% respectively.

  20. Uranium Dioxides and Debris Fragments Released to the Environment with Cesium-Rich Microparticles from the Fukushima Daiichi Nuclear Power Plant.

    Science.gov (United States)

    Ochiai, Asumi; Imoto, Junpei; Suetake, Mizuki; Komiya, Tatsuki; Furuki, Genki; Ikehara, Ryohei; Yamasaki, Shinya; Law, Gareth T W; Ohnuki, Toshihiko; Grambow, Bernd; Ewing, Rodney C; Utsunomiya, Satoshi

    2018-03-06

    Trace U was released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) during the meltdowns, but the speciation of the released components of the nuclear fuel remains unknown. We report, for the first time, the atomic-scale characteristics of nanofragments of the nuclear fuels that were released from the FDNPP into the environment. Nanofragments of an intrinsic U-phase were discovered to be closely associated with radioactive cesium-rich microparticles (CsMPs) in paddy soils collected ∼4 km from the FDNPP. The nanoscale fuel fragments were either encapsulated by or attached to CsMPs and occurred in two different forms: (i) UO 2+X nanocrystals of ∼70 nm size, which are embedded into magnetite associated with Tc and Mo on the surface and (ii) Isometric (U,Zr)O 2+X nanocrystals of ∼200 nm size, with the U/(U+Zr) molar ratio ranging from 0.14 to 0.91, with intrinsic pores (∼6 nm), indicating the entrapment of vapors or fission-product gases during crystallization. These results document the heterogeneous physical and chemical properties of debris at the nanoscale, which is a mixture of melted fuel and reactor materials, reflecting the complex thermal processes within the FDNPP reactor during meltdown. Still CsMPs are an important medium for the transport of debris fragments into the environment in a respirable form.

  1. 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

  2. Carbon dioxide absorbent and method of using the same

    Science.gov (United States)

    Perry, Robert James [Niskayuna, NY; Lewis, Larry Neil [Scotia, NY; O'Brien, Michael Joseph [Clifton Park, NY; Soloveichik, Grigorii Lev [Latham, NY; Kniajanski, Sergei [Clifton Park, NY; Lam, Tunchiao Hubert [Clifton Park, NY; Lee, Julia Lam [Niskayuna, NY; Rubinsztajn, Malgorzata Iwona [Ballston Spa, NY

    2011-10-04

    In accordance with one aspect, the present invention provides an amino-siloxane composition comprising at least one of structures I, II, III, IV or V said compositions being useful for the capture of carbon dioxide from gas streams such as power plant flue gases. In addition, the present invention provides methods of preparing the amino-siloxane compositions are provided. Also provided are methods for reducing the amount of carbon dioxide in a process stream employing the amino-siloxane compositions of the invention as species which react with carbon dioxide to form an adduct with carbon dioxide. The reaction of the amino-siloxane compositions provided by the present invention with carbon dioxide is reversible and thus, the method provides for multicycle use of said compositions.

  3. Carbon dioxide and climate

    International Nuclear Information System (INIS)

    1991-10-01

    Global climate change is a serious environmental concern, and the US has developed ''An Action Agenda'' to deal with it. At the heart of the US effort is the US Global Change Research Program (USGCRP), which has been developed by the Committee on Earth and Environmental Sciences (CEES) of the Federal Coordinating Council for Sciences, Engineering, and Technology (FCCSET). The USGCRP will provide the scientific basis for sound policy making on the climate-change issue. The DOE contribution to the USGCRP is the Carbon Dioxide Research Program, which now places particular emphasis on the rapid improvement of the capability to predict global and regional climate change. DOE's Carbon Dioxide Research Program has been addressing the carbon dioxide-climate change connection for more than twelve years and has provided a solid scientific foundation for the USGCRP. The expansion of the DOE effort reflects the increased attention that the Department has placed on the issue and is reflected in the National Energy Strategy (NES) that was released in 1991. This Program Summary describes projects funded by the Carbon Dioxide Research Program during FY 1991 and gives a brief overview of objectives, organization, and accomplishments. The Environmental Sciences Division of the Office of Health and Environmental Research, Office of Energy Research supports a Carbon Dioxide Research Program to determine the scientific linkage between the rise of greenhouse gases in the atmosphere, especially carbon dioxide, and climate and vegetation change. One facet is the Core CO 2 Program, a pioneering program that DOE established more than 10 years ago to understand and predict the ways that fossil-fuel burning could affect atmospheric CO 2 concentration, global climate, and the Earth's biosphere. Major research areas are: global carbon cycle; climate detection and models of climate change; vegetation research; resource analysis; and, information and integration

  4. First and Second Law Analyses of Trans-critical N2O Refrigeration Cycle Using an Ejector

    Directory of Open Access Journals (Sweden)

    Damoon Aghazadeh Dokandari

    2018-04-01

    Full Text Available An ejector-expansion refrigeration cycle using nitrous oxide was assessed. Thermodynamic analyses, including energy and exergy analyses, were carried out to investigate the effects on performance of several key factors in the system. The results show that the ejector-expansion refrigeration cycle (EERC has a higher maximum coefficient of performance and exergy efficiency than the internal heat exchanger cycle (IHEC, by 12% and 15%, respectively. The maximum coefficient of performance and exergy efficiency are 14% and 16.5% higher than the corresponding values for the vapor-compression refrigeration cycle (VCRC, respectively. The total exergy destruction for the N2O ejector-expansion cycle is 63% and 53% less than for IHEC and VCRC, respectively. Furthermore, the highest COPs for the vapor-compression refrigeration, the internal heat exchanger and the ejector-expansion refrigeration cycles correspond to a high side pressure of 7.3 MPa, and the highest COPs for the three types of CO2 refrigeration cycles correspond to a high side pressure of 8.5 MPa. Consequently, these lead to a lower electrical power consumption by the compressor.

  5. IMPEDANCE SPECTROSCOPY OF POLYCRYSTALLINE TIN DIOXIDE FILMS

    Directory of Open Access Journals (Sweden)

    D. V. Adamchuck

    2016-01-01

    Full Text Available The aim of this work is the analysis of the influence of annealing in an inert atmosphere on the electrical properties and structure of non-stoichiometric tin dioxide films by means of impedance spectroscopy method. Non-stoichiometric tin dioxide films were fabricated by two-step oxidation of metallic tin deposited on the polycrystalline Al2O3 substrates by DC magnetron sputtering. In order to modify the structure and stoichiometric composition, the films were subjected to the high temperature annealing in argon atmosphere in temperature range 300–800 °С. AC-conductivity measurements of the films in the frequency range 20 Hz – 2 MHz were carried out. Variation in the frequency dependencies of the real and imaginary parts of the impedance of tin dioxide films was found to occur as a result of high-temperature annealing. Equivalent circuits for describing the properties of films with various structure and stoichiometric composition were proposed. Possibility of conductivity variation of the polycrystalline tin dioxide films as a result of аnnealing in an inert atmosphere was demonstrated by utilizing impedance spectroscopy. Annealing induces the recrystallization of the films, changing in their stoichiometry as well as increase of the sizes of SnO2 crystallites. Variation of electrical conductivity and structure of tin dioxide films as a result of annealing in inert atmosphere was confirmed by X-ray diffraction analysis. Analysis of the impedance diagrams of tin dioxide films was found to be a powerful tool to study their electrical properties. 

  6. Does Carbon Dioxide Predict Temperature?

    OpenAIRE

    Mytty, Tuukka

    2013-01-01

    Does carbon dioxide predict temperature? No it does not, in the time period of 1880-2004 with the carbon dioxide and temperature data used in this thesis. According to the Inter Governmental Panel on Climate Change(IPCC) carbon dioxide is the most important factor in raising the global temperature. Therefore, it is reasonable to assume that carbon dioxide truly predicts temperature. Because this paper uses observational data it has to be kept in mind that no causality interpretation can be ma...

  7. 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

  8. Carbon Dioxide Sensor Technology.

    Science.gov (United States)

    1983-04-01

    second gas permeable membrane separates a compartment containing the non-aqueous " solvent dimethylsulfoxide , ( DMSO ), from the aqueous solution...compartment. In DMSO carbon dioxide can be irreversibly reduced electrochemically to * non-interfering products...current due to its reduction in the DMSO solution is proportional to the partial pressure of CO2 in the gas phase. Overall, the linear response and

  9. Carbon dioxide sensor

    Science.gov (United States)

    Dutta, Prabir K [Worthington, OH; Lee, Inhee [Columbus, OH; Akbar, Sheikh A [Hilliard, OH

    2011-11-15

    The present invention generally relates to carbon dioxide (CO.sub.2) sensors. In one embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor that incorporates lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3). In another embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor has a reduced sensitivity to humidity due to a sensing electrode with a layered structure of lithium carbonate and barium carbonate. In still another embodiment, the present invention relates to a method of producing carbon dioxide (CO.sub.2) sensors having lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3).

  10. Balancing atmospheric carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Goreau, T.J. (Discovery Bay Marine Laboratory, Univ. of the West Indies (JM))

    1990-01-01

    Rising carbon dioxide and global temperatures are causing increasing worldwide concern, and pressure towards an international law of the atmosphere is rapidly escalating, yet widespread misconceptions about the greenhouse effect's inevitability, time scale, and causes have inhibited effective consensus and action. Observations from Antarctic ice cores, Amazonian rain forests, and Carribean coral reefs suggest that the biological effects of climate change may be more severe than climate models predict. Efforts to limit emissions from fossil-fuel combustion alone are incapable of stabilizing levels of carbon dioxide in the atmosphere. Stabilizing atmospheric carbon dioxide requires coupled measures to balance sources and sinks of the gas, and will only be viable with large-scale investments in increased sustainable productivity on degraded tropical soils, and in long-term research on renewable energy and biomass product development in the developing countries. A mechanism is outlined which directly links fossil-fuel combustion sources of carbon dioxide to removal via increasing biotic productivity and storage. A preliminary cost-benefit analysis suggests that such measures are very affordable, costing far less than inaction. (With 88 refs.).

  11. Balancing atmospheric carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Goreau, T J [Discovery Bay Marine Laboratory, Univ. of the West Indies (JM)

    1990-01-01

    Rising carbon dioxide and global temperatures are causing increasing worldwide concern, and pressure towards an international law of the atmosphere is rapidly escalating, yet widespread misconceptions about the greenhouse effect's inevitability, time scale, and causes have inhibited effective consensus and action. Observations from Antarctic ice cores, Amazonian rain forests, and Carribean coral reefs suggest that the biological effects of climate change may be more severe than climate models predict. Efforts to limit emissions from fossil-fuel combustion alone are incapable of stabilizing levels of carbon dioxide in the atmosphere. Stabilizing atmospheric carbon dioxide requires coupled measures to balance sources and sinks of the gas, and will only be viable with large-scale investments in increased sustainable productivity on degraded tropical soils, and in long-term research on renewable energy and biomass product development in the developing countries. A mechanism is outlined which directly links fossil-fuel combustion sources of carbon dioxide to removal via increasing biotic productivity and storage. A preliminary cost-benefit analysis suggests that such measures are very affordable, costing far less than inaction. (With 88 refs.).

  12. POSSIBILITIES OF CARBON DIOXIDE FIXATION BY MICROALGAE IN REFINERY

    OpenAIRE

    Šingliar, Michal; Mikulec, Jozef; Kušnir, Patrik; Polakovičova, Gabriela

    2013-01-01

    Capture and sequestration of carbon dioxide is one of the most critical challenges today for businesses and governments worldwide. Thousands of emitting power plants and industries worldwide face this costly challenge – reduce the CO2 emissions or pay penalties. One possibility for carbon dioxide sequestration is its fixation in microalgae. Microalgae can sequester CO2 from flue gases emitted from fossil fuel-fired refinery plants and units, thereby reducing emissions of a major greenhouse ga...

  13. The formation of ethane from carbon dioxide under cold plasma

    International Nuclear Information System (INIS)

    Zhang Xiuling; Zhang Lin; Dai Bin; Gong Weimin; Liu Changhou

    2001-01-01

    Pulsed-corona plasma has been used as a new method for ethane dehydrogenation at low temperature and normal pressure using carbon dioxide as an oxidant. The effect of carbon dioxide content in the feed, power input, and flow rate of the reactants on the ethane dehydrogenation has been investigated. The experimental results show that the conversion of ethane increases with the increasing in the amount of carbon dioxide in the feed. The yield of ethylene and acetylene decreases with the increasing in the yield of carbon monoxide, indicating that the increased carbon dioxide leads to the part of ethylene and acetylene being oxidized to carbon monoxide. Power input is primarily an electrical parameter in pulsed-corona plasma, which plays an important role in reactant conversion and product formation. When the power input reaches 16 W, ethane conversion is 41.0% and carbon dioxide conversion is 26.3%. The total yield of ethylene and acetylene is 15.6%. The reduced flow rate of feed improves the conversion of ethane, carbon dioxide and the yield of acetylene, and induces carbon deposit as well

  14. Carbon dioxide dangers demonstration model

    Science.gov (United States)

    Venezky, Dina; Wessells, Stephen

    2010-01-01

    Carbon dioxide is a dangerous volcanic gas. When carbon dioxide seeps from the ground, it normally mixes with the air and dissipates rapidly. However, because carbon dioxide gas is heavier than air, it can collect in snowbanks, depressions, and poorly ventilated enclosures posing a potential danger to people and other living things. In this experiment we show how carbon dioxide gas displaces oxygen as it collects in low-lying areas. When carbon dioxide, created by mixing vinegar and baking soda, is added to a bowl with candles of different heights, the flames are extinguished as if by magic.

  15. Nuclear power and other thermal power

    International Nuclear Information System (INIS)

    Bakke, J.

    1978-01-01

    Some philosophical aspects of mortality statistics are first briefly mentioued, then the environmental problems of, first, nuclear power plants, then fossil fuelled power plants are summarised. The effects of releases of carbon dioxide, sulphur dioxide and nitrogen oxides are briefly discussed. The possible health effects of radiation from nuclear power plants and those of gaseous and particulate effluents from fossil fuel plants are also discussed. It is pointed out that in choosing between alternative evils the worst course is to make no choice at all, that is, failure to install thermal power plants will lead to isolated domestic burning of fossil fuels which is clearly the worst situation regarding pollution. (JIW)

  16. Methanation of Carbon Dioxide

    OpenAIRE

    Goodman, Daniel Jacob

    2013-01-01

    The emission of greenhouse gases into the atmosphere has been linked to global warming. Carbon dioxide's (CO2) one of the most abundant greenhouse gases. Natural gas, mainly methane, is the cleanest fossil fuel for electricity production helping meet the United States ever growing energy needs. The methanation of CO2 has the potential to address both of these problems if a catalyst can be developed that meets the activity, economic and environmental requirements to industrialize the process. ...

  17. CARBON DIOXIDE FIXATION.

    Energy Technology Data Exchange (ETDEWEB)

    FUJITA,E.

    2000-01-12

    Solar carbon dioxide fixation offers the possibility of a renewable source of chemicals and fuels in the future. Its realization rests on future advances in the efficiency of solar energy collection and development of suitable catalysts for CO{sub 2} conversion. Recent achievements in the efficiency of solar energy conversion and in catalysis suggest that this approach holds a great deal of promise for contributing to future needs for fuels and chemicals.

  18. Production of uranium dioxide

    International Nuclear Information System (INIS)

    Hart, J.E.; Shuck, D.L.; Lyon, W.L.

    1977-01-01

    A continuous, four stage fluidized bed process for converting uranium hexafluoride (UF 6 ) to ceramic-grade uranium dioxide (UO 2 ) powder suitable for use in the manufacture of fuel pellets for nuclear reactors is disclosed. The process comprises the steps of first reacting UF 6 with steam in a first fluidized bed, preferably at about 550 0 C, to form solid intermediate reaction products UO 2 F 2 , U 3 O 8 and an off-gas including hydrogen fluoride (HF). The solid intermediate reaction products are conveyed to a second fluidized bed reactor at which the mol fraction of HF is controlled at low levels in order to prevent the formation of uranium tetrafluoride (UF 4 ). The first intermediate reaction products are reacted in the second fluidized bed with steam and hydrogen at a temperature of about 630 0 C. The second intermediate reaction product including uranium dioxide (UO 2 ) is conveyed to a third fluidized bed reactor and reacted with additional steam and hydrogen at a temperature of about 650 0 C producing a reaction product consisting essentially of uranium dioxide having an oxygen-uranium ratio of about 2 and a low residual fluoride content. This product is then conveyed to a fourth fluidized bed wherein a mixture of air and preheated nitrogen is introduced in order to further reduce the fluoride content of the UO 2 and increase the oxygen-uranium ratio to about 2.25

  19. Mixing Under Transcritical Flow Conditions

    Science.gov (United States)

    2011-03-01

    between them. The signals were then sent to two amplifiers (Krohn-Hite model 7500 and a Trek model PZD2000A), one for each piezo-siren. The amplified...In Annual Research Briefs, pages 73–84. Center for Turbulence Research, NASA Ames/Stanford Univ., 1999. [61] C. Segal and SA Polikhov. Subcritical to

  20. The cohesive energy of uranium dioxide and thorium dioxide

    International Nuclear Information System (INIS)

    Childs, B.G.

    1958-08-01

    Theoretical values have been calculated of the heats of formation of uranium dioxide and thorium dioxide on the assumption that the atomic binding forces in these solids are predominantly ionic in character. The good agreement found between the theoretical and observed values shows that the ionic model may, with care, be used in calculating the energies of defects in the uranium and thorium dioxide crystal structures. (author)

  1. Thermodynamic analysis of a binary power cycle for different EGS geofluid temperatures

    International Nuclear Information System (INIS)

    Zhang Fuzen; Jiang Peixe

    2012-01-01

    Enhanced Geothermal Systems show promise for meeting growing energy demands. The Organic Rankine Cycle (ORC) can be used to convert low and medium-temperature geothermal energy to electricity, but the working fluid must be carefully selected for the ORC system design. This paper compares the system performance using R134a, isobutane, R245fa and isopentane for four typical geofluid temperatures below 200 °C. Three type (subcritical, superheated and transcritical) power generation cycles and two heat transfer control models (total heat control model and vaporization control model) are used for different EGS source temperatures and working fluids. This paper presents a basic analysis method to select the most suitable working fluid and to optimize the operating and design parameters for a given EGS resource based on the thermodynamics. - Highlights: ► We present a method to selecting working fluids for EGS resources. ► Working fluids with critical temperatures near geofluid temperature is priority. ► Operating conditions requiring use of total heat control model give good behave. ► Transcritical cycle is good choice.

  2. Cogeneration and carbon dioxide emissions of a city - Legal aspects and distributed heat and power production; L'impact des couplages chaleur-force sur les emissions de CO{sub 2} d'une ville. Cadre institutionnel et productions decentralisees

    Energy Technology Data Exchange (ETDEWEB)

    Cherix, G. [Centre de Recherches Energetiques et Municipales (CREM), Martigny (Switzerland)

    2010-07-01

    This article reviews the impacts of combined generation of heat and power in urban areas on energy consumption and carbon dioxide emissions and emphasises the necessity of accelerating the implementation of such systems, given the present climate change and its negative consequences. The author describes in particular the relevance of distributed cogeneration units with natural gas or biogas engines. These units efficiently reduce the primary energy consumption. Local, regional and national authorities should create the framework conditions favorable to the rapid development of this technology.

  3. Molybdenum dioxide-molybdenite roasting

    International Nuclear Information System (INIS)

    Sabacky, B.J.; Hepworth, M.T.

    1984-01-01

    A process is disclosed for roasting molybdenite concentrates directly to molybdenum dioxide. The process comprises establishing a roasting zone having a temperature of about 700 0 C. to about 800 0 C., introducing into the roasting zone particulate molybdenum dioxide and molybdenite in a weight ratio of at least about 2:1 along with an oxygen-containing gas in amount sufficient to oxidize the sulfur content of the molybdenite to molybdenum dioxide

  4. Process for sequestering carbon dioxide and sulfur dioxide

    Science.gov (United States)

    Maroto-Valer, M Mercedes [State College, PA; Zhang, Yinzhi [State College, PA; Kuchta, Matthew E [State College, PA; Andresen, John M [State College, PA; Fauth, Dan J [Pittsburgh, PA

    2009-10-20

    A process for sequestering carbon dioxide, which includes reacting a silicate based material with an acid to form a suspension, and combining the suspension with carbon dioxide to create active carbonation of the silicate-based material, and thereafter producing a metal salt, silica and regenerating the acid in the liquid phase of the suspension.

  5. Carbon dioxide and climate

    Energy Technology Data Exchange (ETDEWEB)

    1990-10-01

    Scientific and public interest in greenhouse gases, climate warming, and global change virtually exploded in 1988. The Department's focused research on atmospheric CO{sub 2} contributed sound and timely scientific information to the many questions produced by the groundswell of interest and concern. Research projects summarized in this document provided the data base that made timely responses possible, and the contributions from participating scientists are genuinely appreciated. In the past year, the core CO{sub 2} research has continued to improve the scientific knowledge needed to project future atmospheric CO{sub 2} concentrations, to estimate climate sensitivity, and to assess the responses of vegetation to rising concentrations of CO{sub 2} and to climate change. The Carbon Dioxide Research Program's goal is to develop sound scientific information for policy formulation and governmental action in response to changes of atmospheric CO{sub 2}. The Program Summary describes projects funded by the Carbon Dioxide Research Program during FY 1990 and gives a brief overview of objectives, organization, and accomplishments.

  6. The carbon dioxide problem - a challenge to environmental protection

    International Nuclear Information System (INIS)

    Hlubek, W.; Spalthoff, F.J.

    1989-01-01

    Over the last century, man's activities on earth have sent off trace gases into the planet's atmosphere that have been concentrating to a level posing a threat to the global climate. Since scientists particularly spotted carbon dioxide as the main contributor to what we now call the greenhouse effect, there is urgent need for measures reducing carbon dioxide emission worldwide, may be on the basis of a global convention to be signed by both the industrialised and the developing countries. The industrialised countries, which certainly are the main pollutors, also will have the technological and financial resources to respond to the challenge of global warning more directly and faster than the developing countries. The power industry's management in the FRG is taking the problem seriously and has already come out with strategies for curbing carbon dioxide emissions from fossil-fuel power plant. (orig.) [de

  7. Nuclear power

    International Nuclear Information System (INIS)

    King, P.

    1990-01-01

    Written from the basis of neutrality, neither for nor against nuclear power this book considers whether there are special features of nuclear power which mean that its development should be either promoted or restrained by the State. The author makes it dear that there are no easy answers to the questions raised by the intervention of nuclear power but calls for openness in the nuclear decision making process. First, the need for energy is considered; most people agree that energy is the power to progress. Then the historicalzed background to the current position of nuclear power is given. Further chapters consider the fuel cycle, environmental impacts including carbon dioxide emission and the greenhouse effect, the costs, safety and risks and waste disposal. No conclusion either for or against nuclear power is made. The various shades of opinion are outlined and the arguments presented so that readers can come to their own conclusions. (UK)

  8. Decontamination of radioactive clothing using microemulsion in carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jaeryong; Jang, Jina; Park, Kwangheon; Kim, Hongdoo; Kim, Hakwon [Kyunghee Univ., Seoul (Korea, Republic of); Yim, Sanghak; Yoon, Weonseob [Ulchin Nuclear Power Site, Ulchin (Korea, Republic of)

    2006-07-01

    Nuclear power is intrinsically a clean energy source due to its high energy density and low generation of waste. However, as the nuclear industry grows, a variety of radioactive wastes are increased gradually. Major subjects include contaminated components, tools, equipment, containers and facilities as well as nuclear waste such as uranium scrap and radioactive clothing. The radioactive waste can be classified by its creation. There are Trans-Uranium Nuclides (TRU), Fission Products (FP) and corrosion products. Nuclear decontamination has become an important issue in the nuclear industry. The conventional methods have some problems such as the production of secondary wastes and the use of toxic solvents. We need to develop a new method of decontamination and suggest a use of microemulsion in carbon dioxide to overcome these disadvantages. The microemulsion is the clear solution that contains the water, surfactant and carbon dioxide. The surfactant surrounded the droplet into carbon dioxide and this state is thermodynamically stable. That is, the microemulsion has a structure similar to that of a conventional water-based surfactant system. Generally, the size of droplet is about 5 {approx} 10nm. The microemulsion is able to decontaminate radioactive waste so that the polar substance is removed by water and the non-polar substance is removed by carbon dioxide. After the decontamination process, the microemulsion is separated easily to surfactant and water by decreasing the pressure under the cloud point. This way, only radioactive wastes are left in the system. Cleaned carbon dioxide is then collected and reused. Thus, there are no secondary wastes. Carbon dioxide is considered an alternative process medium. This is because it is non-toxic, non-flammable, inexpensive and easy to handle. Additionally, the tunable properties of carbon dioxide through pressure and temperature control are versatile for use in extracting organic materials. In this paper, we examine the

  9. Decontamination of radioactive clothing using microemulsion in carbon dioxide

    International Nuclear Information System (INIS)

    Yoo, Jaeryong; Jang, Jina; Park, Kwangheon; Kim, Hongdoo; Kim, Hakwon; Yim, Sanghak; Yoon, Weonseob

    2006-01-01

    Nuclear power is intrinsically a clean energy source due to its high energy density and low generation of waste. However, as the nuclear industry grows, a variety of radioactive wastes are increased gradually. Major subjects include contaminated components, tools, equipment, containers and facilities as well as nuclear waste such as uranium scrap and radioactive clothing. The radioactive waste can be classified by its creation. There are Trans-Uranium Nuclides (TRU), Fission Products (FP) and corrosion products. Nuclear decontamination has become an important issue in the nuclear industry. The conventional methods have some problems such as the production of secondary wastes and the use of toxic solvents. We need to develop a new method of decontamination and suggest a use of microemulsion in carbon dioxide to overcome these disadvantages. The microemulsion is the clear solution that contains the water, surfactant and carbon dioxide. The surfactant surrounded the droplet into carbon dioxide and this state is thermodynamically stable. That is, the microemulsion has a structure similar to that of a conventional water-based surfactant system. Generally, the size of droplet is about 5 ∼ 10nm. The microemulsion is able to decontaminate radioactive waste so that the polar substance is removed by water and the non-polar substance is removed by carbon dioxide. After the decontamination process, the microemulsion is separated easily to surfactant and water by decreasing the pressure under the cloud point. This way, only radioactive wastes are left in the system. Cleaned carbon dioxide is then collected and reused. Thus, there are no secondary wastes. Carbon dioxide is considered an alternative process medium. This is because it is non-toxic, non-flammable, inexpensive and easy to handle. Additionally, the tunable properties of carbon dioxide through pressure and temperature control are versatile for use in extracting organic materials. In this paper, we examine the

  10. Uranium dioxide pellets

    International Nuclear Information System (INIS)

    Zawidzki, T.W.

    1982-01-01

    A process for the preparation of a sintered, high density, large crystal grain size uranium dioxide pellet is described which involves: (i) reacting a uranyl nitrate of formula UO 2 (NO 3 ) 2 .6H 2 O with a sulphur source, at a temperature of from about 300 deg. C to provide a sulphur-containing uranium trioxide; (ii) reacting the thus-obtained modified uranium trioxide with ammonium nitrate to form an insoluble sulphur-containing ammonium uranate; (iii) neutralizing the thus-formed slurry with ammonium hydroxide to precipitate out as an insoluble ammonium uranate the remaining dissolved uranium; (iv) recovering the thus-formed precipitates in a dry state; (v) reducing the dry precipitate to UO 2 , and forming it into 'green' pellets; and (vi) sintering the pellets in a hydrogen atmosphere at an elevated temperature

  11. Forecasting carbon dioxide emissions.

    Science.gov (United States)

    Zhao, Xiaobing; Du, Ding

    2015-09-01

    This study extends the literature on forecasting carbon dioxide (CO2) emissions by applying the reduced-form econometrics approach of Schmalensee et al. (1998) to a more recent sample period, the post-1997 period. Using the post-1997 period is motivated by the observation that the strengthening pace of global climate policy may have been accelerated since 1997. Based on our parameter estimates, we project 25% reduction in CO2 emissions by 2050 according to an economic and population growth scenario that is more consistent with recent global trends. Our forecasts are conservative due to that we do not have sufficient data to fully take into account recent developments in the global economy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Uranium dioxide calcining apparatus

    International Nuclear Information System (INIS)

    Cole, E.A.; Peterson, R.S.

    1978-01-01

    This invention relates to an improved continuous calcining apparatus for consistently and controllably producing from calcinable reactive solid compounds of uranium, such as ammonium diuranate, uranium dioxide (UO 2 ) having an oxygen to uranium ratio of less than 2.2. The apparatus comprises means at the outlet end of a calciner kiln for receiving hot UO 2 , means for cooling the UO 2 to a temperature of below 100 deg C and conveying the cooled UO 2 to storage or to subsequent UO 2 processing apparatus where it finally comes into contact with air, the means for receiving cooling and conveying being sealed to the outlet end of the calciner and being maintained full of UO 2 and so operable as to exclude atmospheric oxygen from coming into contact with any UO 2 which is at elevated temperatures where it would readily oxidize, without the use of extra hydrogen gas in said means. (author)

  13. Carbon dioxide and future climate

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, J M

    1977-03-01

    The addition of carbon dioxide to the atmosphere due to burning fossil fuel is discussed. The release rate of carbon dioxide has been growing since at least 1950 at an average rate of 4.3% per year. If all known fossil fuel reserves in the world are consumed, a total of between 5 and 14 times the present amount of carbon dioxide in the atmosphere will be released. The oceans would then be unlikely to withdraw the proportion of perhaps 40% which they are believed to have withdrawn up to the present. The increase in the atmosphere would be in excess of 3 times or conceivably ten times the present amount. If the reserves are used up within a few hundred years, more than half the excess carbon dioxide would remain in the atmosphere after a thousand years. The ''greenhouse'' effect of carbon dioxide is explained. The simulation with numerical models of the effects of carbon dioxide on atmospheric radiation fluxes is discussed. An estimated increase in the average annual temperature of the earth of 2.4 to 2.9C is given for doubling the carbon dioxide content; also a 7% increase in global average precipitation. The effect of increasing carbon dioxide on global mean temperature is viewed in the perspective of the glacial-interglacial cycles. The warming effect of carbon dioxide may induce a ''super-interglacial'' on the present interglacial which is expected to decline toward a new ice age in the next several thousand years. Finally it is proposed that it may be necessary to phase out the use of fossil fuels before all the knowledge is acquired which would necessitate such an action.

  14. Made-to-order metal-organic frameworks for trace carbon dioxide removal and air capture

    KAUST Repository

    Shekhah, Osama; Belmabkhout, Youssef; Chen, Zhijie; Guillerm, Vincent; Cairns, Amy; Adil, Karim; Eddaoudi, Mohamed

    2014-01-01

    Direct air capture is regarded as a plausible alternate approach that, if economically practical, can mitigate the increasing carbon dioxide emissions associated with two of the main carbon polluting sources, namely stationary power plants

  15. Extraction of Uranium Using Nitrogen Dioxide and Carbon Dioxide for Spent Fuel Reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Kayo Sawada; Daisuke Hirabayashi; Youichi Enokida [EcoTopia Science Institute, Nagoya University, Nagoya, 464-8603 (Japan)

    2008-07-01

    For the reprocessing of spent nuclear fuels, a new method to extract actinides from spent fuel using highly compressed gases, nitrogen dioxide and carbon dioxide was proposed. Uranium extraction from broken pieces, whose average grain size was 5 mm, of uranium dioxide pellet with nitrogen dioxide and carbon dioxide was demonstrated in the present study. (authors)

  16. Reducing carbon dioxide to products

    Science.gov (United States)

    Cole, Emily Barton; Sivasankar, Narayanappa; Parajuli, Rishi; Keets, Kate A

    2014-09-30

    A method reducing carbon dioxide to one or more products may include steps (A) to (C). Step (A) may bubble said carbon dioxide into a solution of an electrolyte and a catalyst in a divided electrochemical cell. The divided electrochemical cell may include an anode in a first cell compartment and a cathode in a second cell compartment. The cathode may reduce said carbon dioxide into said products. Step (B) may adjust one or more of (a) a cathode material, (b) a surface morphology of said cathode, (c) said electrolyte, (d) a manner in which said carbon dioxide is bubbled, (e), a pH level of said solution, and (f) an electrical potential of said divided electrochemical cell, to vary at least one of (i) which of said products is produced and (ii) a faradaic yield of said products. Step (C) may separate said products from said solution.

  17. Method for carbon dioxide sequestration

    Science.gov (United States)

    Wang, Yifeng; Bryan, Charles R.; Dewers, Thomas; Heath, Jason E.

    2017-12-05

    A method for geo-sequestration of a carbon dioxide includes selection of a target water-laden geological formation with low-permeability interbeds, providing an injection well into the formation and injecting supercritical carbon dioxide (SC-CO.sub.2) and water or bine into the injection well under conditions of temperature, pressure and density selected to cause the fluid to enter the formation and splinter and/or form immobilized ganglia within the formation.

  18. Full-scale multi-ejector module for a carbon dioxide supermarket refrigeration system: Numerical study of performance evaluation

    International Nuclear Information System (INIS)

    Bodys, Jakub; Palacz, Michal; Haida, Michal; Smolka, Jacek; Nowak, Andrzej J.; Banasiak, Krzysztof; Hafner, Armin

    2017-01-01

    Highlights: • A numerical study of the full-scale multi-ejector module performance was presented. • The module was characterised by stable operation in each considered configuration. • The module showed a high total efficiency for all the operating conditions. - Abstract: The performance of fixed ejectors installed in a multi-ejector module in a carbon dioxide refrigeration system is discussed in this paper. To analyse the module operation, three-dimensional ejector models including the inlet and outlet collecting ducts were considered. The tests were performed for three of four vapour ejectors of different sizes that compose the multi-ejector pack. The testing modes included the serial and parallel operation of the fixed units in operating conditions that are characteristic for the supermarket refrigeration unit working at high ambient temperatures. All numerical simulations were performed using the validated Homogeneous Equilibrium Model implemented on the ejectorPL computational tool for typical transcritical parameters at the motive nozzle port. The detailed analysis was executed separately for the ejectors and the ducts of the module collectors. The results discussion concerned the crucial parameters for such an installation like the pressure and vapour quality distribution. Negligible influence of the motive nozzle collector and a crucial influence of the outlet collector shape was indicated. The global performance analysis showed that the multi-ejector pack provides high and stable performance of all installed ejectors over the entire range of the considered operating conditions for supermarket application. Areas of the possible pressure loss reduction and the uniformity growth in the vapour quality distribution were presented. Finally, according to the multi-ejector pack ducts analysis, the potential areas for module shape optimisation were indicated as well.

  19. Transcritical CO{sub 2} process with work output expansion - operating experience and experimental results; Transkritischer CO{sub 2}-Prozess mit arbeitsleistender Entspannung - Betriebserfahrungen und Versuchsergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Heyl, P.; Quack, H. [Technische Univ. Dresden (Germany). Lehrstuhl fuer Kaelte- und Kryotechnik

    2000-07-01

    Carbon dioxide is an ecologically acceptable and safe refrigerant, but there are energetic disadvantages in certain processes of refrigeration, air conditioning and heat pumpt technology. The thermodynamic losses of carbon dioxide are caused on the one hand by high end temperatures of the compression stage and on the other hand by relatively high losses of irreversible throttling expansion. The efficiency could be enhanced by work output during expansion, which is utilized for compression in the second stage of a two-stage compressor. In order to keep the machinery simple, both the expansion with work output and the compression take place inside a fully autonomous combined free-piston unit. The practical results achieved so far prove the validity of the theoretical predictions and show that the machine works both independently and also when integrated in a refrigeration system. Further investigations will be required in order to improve and simplify the new expansion-compression machine. [German] Der Einsatz von Kohlendioxid als Kaeltemittel ist oekologisch wuenschenswert und sicherheitstechnisch unproblematisch. Einer breiten Anwendung von Kohlendioxid wirken vor allem energetische Nachteile in bestimmten Prozessen der Kaelte-, Klima- und Waermepumpentechnik entgegen. Im Vergleich zu den heute ueblichen Kaeltemitteln sind die thermodynamischen Verluste des Kohlendioxids zum einen in den hohen Verdichtungsendtemperaturen und zum anderen in den relativ hohen Verlusten der irreversiblen Drosselentspannung begruendet. Eine Moeglichkeit, die Effizienz deutlich zu erhoehen und dadurch mit konkurrierenden Systemen gleichzuziehen, ist der Einsatz einer arbeitsleistenden Entspannung des Kaeltemittels Kohlendioxid einschliesslich der Nutzung fuer die Verdichtung des Kohlendioxids in der zweiten Stufe einer zweistufigen Kompression. Fuer einen moeglichst geringen anlagentechnischen Aufwand wird eine kombinierte Expansions-Kompressions-Maschine verwendet, in der sowohl die

  20. Effect of Novel Quercetin Titanium Dioxide-Decorated Multi-Walled Carbon Nanotubes Nanocomposite on Bacillus subtilis Biofilm Development

    DEFF Research Database (Denmark)

    Raie, Diana S; Mhatre, Eisha; El-Desouki, Doaa S

    2018-01-01

    The present work was targeted to design a surface against cell seeding and adhering of bacteria, Bacillus subtilis. A multi-walled carbon nanotube/titanium dioxide nano-power was produced via simple mixing of carbon nanotube and titanium dioxide nanoparticles during the sol-gel process followed...

  1. Carbon dioxide: emissions and effects

    Energy Technology Data Exchange (ETDEWEB)

    Smith, I M

    1982-01-01

    This review provides a comprehensive guide to work carried out since 1978 in the many disciplines involved in this complex issue. Possible scenarios for carbon dioxide emissions, sources and sinks in the carbon cycle and for climatic changes are examined. The current concensus (by no means unanimous) of specialists on this issue appears to be that a continuation of reduced trends in energy consumption since 1973 is likely to double the atmospheric carbon dioxide concentration to 600 ppmv during the latter part of the next century. However, a higher demand scenario, requiring an upper limit of coal production, would bring forward the doubling to about the middle of the next century. Current climatic models predict that such a concentration of carbon dioxide would cause an average global warming of from 1.0 to 4.5/sup 0/C which might be delayed by the thermal inertia of the oceans. A warming due to estimated increases in carbon dioxide should, if the model results are correct, become apparent at the end of this century. Regional climatic changes are likely to vary considerably and prove disadvantageous to some regions and beneficial to others. Different strategies for dealing with the carbon dioxide issue are considered: no response, alleviation, countermeasures and prevention. It is concluded that uncertainties do not justify either the use of carbon dioxide disposal and other technical fixes at present or a policy of no further growth in fossil fuel consumption. On the other hand, major efforts to conserve energy would give more time to adapt to changes. The alleviation of climatic impacts and other desirable dual-benefit measures are advocated in addition to continuing international, interdisciplinary research on all aspects.

  2. Carbon Dioxide Absorption Heat Pump

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    2002-01-01

    A carbon dioxide absorption heat pump cycle is disclosed using a high pressure stage and a super-critical cooling stage to provide a non-toxic system. Using carbon dioxide gas as the working fluid in the system, the present invention desorbs the CO2 from an absorbent and cools the gas in the super-critical state to deliver heat thereby. The cooled CO2 gas is then expanded thereby providing cooling and is returned to an absorber for further cycling. Strategic use of heat exchangers can increase the efficiency and performance of the system.

  3. Biofixation of Carbon dioxide by Chlamydomonas sp. in a Tubular Photobioreactor

    Directory of Open Access Journals (Sweden)

    H Hadiyanto

    2012-02-01

    Full Text Available The biogas production from anaerobic digestion is a potential fuel for power generators application, if biogas can be upgraded to the same standards as fossil natural gas by CO2, H2S, and other non-combustible component removal. Microalgae Chlamydomonas sp. has potency to biofix the carbon dioxide and can be used as an additional food ingredient. The variations of flow rate and carbon dioxide concentration in the process resulting different value of biomass production and carbon dioxide biofixation. Biomass production at 40% carbon dioxide concentration obtained 5.685 gr/dm3 at 10% carbon dioxide concentration obtained 4.892 gr/dm3. The greatest value of carbon dioxide absorption occurs at a 40% concentration amounting to 12.09%. The rate of growth and productivity of microalgae tend to rise in 10% and 20% (%v carbon dioxide concentration, but began started a constant at 30% and 40% (%v carbon dioxide concentration. Biomass production tends to increase in light conditions while a constant in dark conditions. This study used Chlamydomonas sp. as media culture and performed on bubble column and tubular reactor with 6 litres of culture medium at a temperature of 28oC and atmospheric pressure.

  4. Carbon Dioxide Embolism during Laparoscopic Surgery

    Science.gov (United States)

    Park, Eun Young; Kwon, Ja-Young

    2012-01-01

    Clinically significant carbon dioxide embolism is a rare but potentially fatal complication of anesthesia administered during laparoscopic surgery. Its most common cause is inadvertent injection of carbon dioxide into a large vein, artery or solid organ. This error usually occurs during or shortly after insufflation of carbon dioxide into the body cavity, but may result from direct intravascular insufflation of carbon dioxide during surgery. Clinical presentation of carbon dioxide embolism ranges from asymptomatic to neurologic injury, cardiovascular collapse or even death, which is dependent on the rate and volume of carbon dioxide entrapment and the patient's condition. We reviewed extensive literature regarding carbon dioxide embolism in detail and set out to describe the complication from background to treatment. We hope that the present work will improve our understanding of carbon dioxide embolism during laparoscopic surgery. PMID:22476987

  5. Hodgkin's disease following thorium dioxide angiography

    Energy Technology Data Exchange (ETDEWEB)

    Gotlieb, A I; Kirk, M E [McGill Univ., Montreal, Quebec (Canada). Dept. of Pathology; Hutchison, J L [Montreal General Hospital, Quebec (Canada)

    1976-09-04

    Hodgkin's disease occurred in a 53-year-old man who, 25 years previously, had undergone cerebral angiography, for which thorium dioxide suspension (Thorotrast) was used. Deposits of thorium dioxide were noted in reticuloendothelial cells in various locations. An association between thorium dioxide administration and the subsequent development of malignant tumours and neoplastic hematologic disorders has previously been reported.

  6. 21 CFR 582.1240 - Carbon dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Carbon dioxide. 582.1240 Section 582.1240 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1240 Carbon dioxide. (a) Product. Carbon dioxide. (b) Conditions of use. This substance is generally...

  7. 21 CFR 73.1575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the requirements...

  8. 40 CFR 180.1195 - Titanium dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or on...

  9. 21 CFR 73.2575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the requirements...

  10. 21 CFR 73.575 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.575 Section 73.575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.575 Titanium dioxide. (a) Identity. (1) The color additive titanium dioxide is synthetically prepared TiO2, free from admixture with other substances. (2) Color...

  11. 21 CFR 73.3126 - Titanium dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891, shall...

  12. Radiation induced sulfur dioxide removal

    International Nuclear Information System (INIS)

    Chmielewski, A.G.

    2000-01-01

    The biggest source of air pollution is the combustion of fossil fuels, were pollutants such as particulate, sulfur dioxide (SO 2 ), nitrogen oxides (NO x ), and volatile organic compounds (VOC) are emitted. Among these pollutants, sulfur dioxide plays the main role in acidification of the environment. The mechanism of sulfur dioxide transformation in the environment is partly photochemical. This is not direct photooxidation, however, but oxidation through formed radicals. Heterogenic reactions play an important role in this transformation as well; therefore, observations from environmental chemistry can be used in air pollution control engineering. One of the most promising technologies for desulfurization of the flue gases (and simultaneous denitrification) is radiation technology with an electron accelerator application. Contrary to the nitrogen oxides (NO x ) removal processes, which is based on pure radiation induced reactions, sulfur dioxide removal depends on two pathways: a thermochemical reaction in the presence of ammonia/water vapor and a radiation set of radiochemical reactions. The mechanism of these reactions and the consequent technological parameters of the process are discussed in this paper. The industrial application of this radiation technology is being implemented in an industrial pilot plant operated by INCT at EPS Kaweczyn. A full-scale industrial plant is currently in operation in China, and two others are under development in Japan and Poland. (author)

  13. Modelling Sublimation of Carbon Dioxide

    Science.gov (United States)

    Winkel, Brian

    2012-01-01

    In this article, the author reports results in their efforts to model sublimation of carbon dioxide and the associated kinetics order and parameter estimation issues in their model. They have offered the reader two sets of data and several approaches to determine the rate of sublimation of a piece of solid dry ice. They presented several models…

  14. Thermal conductivity of uranium dioxide

    International Nuclear Information System (INIS)

    Pillai, C.G.S.; George, A.M.

    1993-01-01

    The thermal conductivity of uranium dioxide of composition UO 2.015 was measured from 300 to 1400 K. The phonon component of the conductivity is found to be quantitatively accounted for by the theoretical expression of Slack derived by modifying the Leibfried-Schlomann equation. (orig.)

  15. High-energy, short-pulse, carbon-dioxide lasers

    International Nuclear Information System (INIS)

    Fenstermacher, C.A.

    1979-01-01

    Lasers for fusion application represent a special class of short-pulse generators; not only must they generate extremely short temporal pulses of high quality, but they must do this at ultra-high powers and satisfy other stringent requirements by this application. This paper presents the status of the research and development of carbon-dioxide laser systems at the Los Alamos Scientific Laboratory, vis-a-vis the fusion requirements

  16. Purification of arsenic contaminated ground water using hydrated manganese dioxide

    International Nuclear Information System (INIS)

    Raje, N.; Swain, K.K.

    2002-01-01

    An analytical methodology has been developed for the separation of arsenic from ground water using inorganic material in neutral medium. The separation procedure involves the quantitative retention of arsenic on hydrated manganese dioxide, in neutral medium. The validity of the separation procedure has been checked by a standard addition method and radiotracer studies. Neutron activation analysis (NAA), a powerful measurement technique, has been used for the quantitative determination of arsenic. (author)

  17. Antibotulinal efficacy of sulfur dioxide in meat.

    Science.gov (United States)

    Tompkin, R B; Christiansen, L N; Shaparis, A B

    1980-01-01

    The addition of sodium metabisulfite as a source of sulfur dioxide delayed botulinal outgrowth in perishable canned comminuted pork when it was temperature abused at 27 degree C. The degree of inhibition was directly related to the level of sulfur dioxide. Levels greater than 100 microgram of sulfur dioxide per g were necessary to achieve significant inhibition when a target level of 100 botulinal spores per g was used. Sodium nitrite partially reduced the efficacy of the sulfur dioxide. Sulfur dioxide offers a new option for the control of botulinal outgrowth in cured or noncured meat and poultry products. PMID:6996613

  18. Electronic structure of the actinides and their dioxides. Application to the defect formation energy and krypton solubility in uranium dioxide

    International Nuclear Information System (INIS)

    Petit, T.; CEA Centre d'Etudes de Grenoble, 38

    1996-01-01

    Uranium dioxide is the standard nuclear fuel used in French h power plants. During irradiation, fission products such as krypton and xenon are created inside fuel pellets. So, gas release could become, at very high burnup, a limiting factor in the reactor exploitation. To study this subject, we have realised calculations using the Density Functional Theory (DFT) into the Local Density Approximation (LDA) and the Atomic Sphere Approximation (ASA). First, we have validated our approach by calculating cohesive properties of thorium, protactinium and uranium metals. The good agreement between our results and experimental values implies that 5f electrons are itinerant. Calculated lattice parameter, cohesive energy and bulk modulus for uranium and thorium dioxides are in very good agreement with experiment. We show that binding between uranium and oxygen atoms is not completely ionic but partially covalent. The question of the electrical conductivity still remains an open problem. We have been able to calculate punctual defect formation energies in uranium dioxide. Accordingly to experimental observations, we find that it is easier to create a defect in the oxygen sublattice than in the uranium sublattice. Finally, we have been able to predict a probable site of krypton atoms in nuclear fuel: the Schottky trio. Experiences of Extended X-ray Absorption Fine structure Spectroscopy (EXAFS) and X-ray Photoelectron Spectroscopy (XPS) on uranium dioxide doped by ionic implantation will help us in the comprehension of the studied phenomena and the interpretation of our calculations. (author)

  19. The Lancet Countdown on PM2·5 pollution-related health impacts of China's projected carbon dioxide mitigation in the electric power generation sector under the Paris Agreement: a modelling study

    OpenAIRE

    Wenjia Cai, PhD; Jingxuan Hui, PhD; Can Wang, ProfPhD; Yixuan Zheng, PhD; Xin Zhang, PhD; Qiang Zhang, ProfPhD; Peng Gong, ProfPhD

    2018-01-01

    Summary: Background: Except for comparing the implementation costs of the Paris Agreement with potential health benefits at the national levels, previous studies have not explored the health impacts of the nationally determined contributions (NDCs) by countries and in regional details. In this Lancet Countdown study, we aimed to estimate and monetise the health benefits of China's NDCs in the electric power generation sector, and then compare them with the implementation costs, both at the n...

  20. Carbon dioxide and climate: too much heat clouds debate

    Energy Technology Data Exchange (ETDEWEB)

    Gribben, J

    1978-12-01

    Technical feature:The possibility of a significant global warming as a result of increased atmospheric carbon dioxide from the burning of fossil fuels (the greenhouse effect) has recently received attention from climatologists and energy policy planners. The greenhouse effect has been used by the pro-nuclear lobby as an argument in favor of a massive commitment to nuclear power generation. While the CO2 problem is real, the solution does not lie in an energy strategy based on nuclear power, which involves as yet unsolved problems of radioactive waste disposal. The economic feasibility of processes for removing CO2 from waste gases should be investigated. (4 graphs, 10 references)

  1. High capacity carbon dioxide sorbent

    Science.gov (United States)

    Dietz, Steven Dean; Alptekin, Gokhan; Jayaraman, Ambalavanan

    2015-09-01

    The present invention provides a sorbent for the removal of carbon dioxide from gas streams, comprising: a CO.sub.2 capacity of at least 9 weight percent when measured at 22.degree. C. and 1 atmosphere; an H.sub.2O capacity of at most 15 weight percent when measured at 25.degree. C. and 1 atmosphere; and an isosteric heat of adsorption of from 5 to 8.5 kilocalories per mole of CO.sub.2. The invention also provides a carbon sorbent in a powder, a granular or a pellet form for the removal of carbon dioxide from gas streams, comprising: a carbon content of at least 90 weight percent; a nitrogen content of at least 1 weight percent; an oxygen content of at most 3 weight percent; a BET surface area from 50 to 2600 m.sup.2/g; and a DFT micropore volume from 0.04 to 0.8 cc/g.

  2. Oxygen and carbon dioxide sensing

    Science.gov (United States)

    Ren, Fan (Inventor); Pearton, Stephen John (Inventor)

    2012-01-01

    A high electron mobility transistor (HEMT) capable of performing as a CO.sub.2 or O.sub.2 sensor is disclosed, hi one implementation, a polymer solar cell can be connected to the HEMT for use in an infrared detection system. In a second implementation, a selective recognition layer can be provided on a gate region of the HEMT. For carbon dioxide sensing, the selective recognition layer can be, in one example, PEI/starch. For oxygen sensing, the selective recognition layer can be, in one example, indium zinc oxide (IZO). In one application, the HEMTs can be used for the detection of carbon dioxide and oxygen in exhaled breath or blood.

  3. Carbon dioxide retention in divers

    Energy Technology Data Exchange (ETDEWEB)

    Florio, J.T.; Mackenzie, D.A.R.; McKenzie, R.S. [ARE Physiological Laboratory, Gosport (United Kingdom)

    1998-04-01

    This report summarises the work carried out at the ARE Physiological Laboratory (ARE(PL)) between July 1978 and December 1983. The work was intended to examine the proposition that some divers have a low ventilatory response to carbon dioxide; that this results in a low ventilatory response to exercise with consequent hypercapnia; and that these characteristics put the diver at a greater-than-normal risk by increasing the individual`s susceptibility to oxygen toxicity and to other hazards associated with diving (e.g. nitrogen narcosis, decompression sickness and hypothermia). The specific aims of the project can be summarised as follows: (a) to demonstrate the existence of divers who exhibit the tendency to `retain carbon dioxide` when working in hyperbaric conditions; (b) to define the circumstances under which such individuals are at risk; (c) to assess the magnitude of the risk; and (d) to recommend ways to eliminate or to reduce the risk. (author)

  4. CARBON DIOXIDE AS A FEEDSTOCK.

    Energy Technology Data Exchange (ETDEWEB)

    CREUTZ,C.; FUJITA,E.

    2000-12-09

    This report is an overview on the subject of carbon dioxide as a starting material for organic syntheses of potential commercial interest and the utilization of carbon dioxide as a substrate for fuel production. It draws extensively on literature sources, particularly on the report of a 1999 Workshop on the subject of catalysis in carbon dioxide utilization, but with emphasis on systems of most interest to us. Atmospheric carbon dioxide is an abundant (750 billion tons in atmosphere), but dilute source of carbon (only 0.036 % by volume), so technologies for utilization at the production source are crucial for both sequestration and utilization. Sequestration--such as pumping CO{sub 2} into sea or the earth--is beyond the scope of this report, except where it overlaps utilization, for example in converting CO{sub 2} to polymers. But sequestration dominates current thinking on short term solutions to global warming, as should be clear from reports from this and other workshops. The 3500 million tons estimated to be added to the atmosphere annually at present can be compared to the 110 million tons used to produce chemicals, chiefly urea (75 million tons), salicylic acid, cyclic carbonates and polycarbonates. Increased utilization of CO{sub 2} as a starting material is, however, highly desirable, because it is an inexpensive, non-toxic starting material. There are ongoing efforts to replace phosgene as a starting material. Creation of new materials and markets for them will increase this utilization, producing an increasingly positive, albeit small impact on global CO{sub 2} levels. The other uses of interest are utilization as a solvent and for fuel production and these will be discussed in turn.

  5. Manufacture of uranium dioxide powder

    International Nuclear Information System (INIS)

    Becker, M.

    1976-01-01

    Uranium dioxide powder is prepared by the AUC (ammonium uranyl carbonate) method. Supplementing the known process steps, the AUC, after separation from the mother liquor, is washed with an ammonium hydrogen carbonate or an NH 4 OH solution and is subsequently post-treated with a liquid which reduces the surface tension of the residual water in an AUC. Such a liquid is, for instance, alcohol

  6. Carbon dioxide capture and storage

    International Nuclear Information System (INIS)

    Durand, B.

    2011-01-01

    The author first highlights the reasons why storing carbon dioxide in geological formations could be a solution in the struggle against global warming and climate change. Thus, he comments various evolutions and prospective data about carbon emissions or fossil energy consumption as well as various studies performed by international bodies and agencies which show the interest of carbon dioxide storage. He comments the evolution of CO 2 contributions of different industrial sectors and activities, notably in France. He presents the different storage modes and methods which concern different geological formations (saline aquifers, abandoned oil or gas fields, not exploitable coal seams) and different processes (sorption, carbonation). He discusses the risks associated with these storages, the storable quantities, evokes some existing installations in different countries. He comments different ways to capture carbon dioxide (in post-combustion, through oxy-combustion, by pre-combustion) and briefly evokes some existing installations. He evokes the issue of transport, and discusses efficiency and cost aspects, and finally has few words on legal aspects and social acceptability

  7. Internal friction in uranium dioxide

    International Nuclear Information System (INIS)

    Paulin Filho, Pedro Iris

    1979-01-01

    The uranium dioxide inelastic properties were studied measuring internal friction at low frequencies (of the order of 1 Hz). The work was developed in the 160 to 400 deg C temperature range. The effect of stoichiometry variation was studied oxidizing the sample with consequent change of the defect structure originally present in the non-stoichiometric uranium dioxide. The presence of a wide and irregular peak due to oxidation was observed at low temperatures. Activation energy calculations indicated the occurrence of various relaxation processes and assuming the existence of a peak between - 80 and - 70 deg C , the absolute value obtained for the activation energy (0,54 eV) is consistent with the observed values determined at medium and high frequencies for the stress induced reorientation of defects. The microstructure effect on the inelastic properties was studied for stoichiometric uranium dioxide, by varying grain size and porosity. These parameters have influence on the high temperature measurements of internal friction. The internal friction variation for temperatures higher than 340 deg C is thought to be due to grain boundary relaxation phenomena. (author)

  8. Laboratory investigations into the reactive transport module of carbon dioxide sequestration and geochemical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Heidaryan, E. [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Masjidosolayman Branch; Enayati, M.; Mokhtari, B. [Iranian Offshore Oil Co., Tehran (Iran, Islamic Republic of)

    2008-07-01

    Over long time periods, geological sequestration in some systems shows mineralization effects or mineral sequestration of carbon dioxide, converting the carbon dioxide to a less mobile form. However, a detailed investigation of these geological systems is needed before disposing of carbon dioxide into these formations. Depleted oil and gas reservoirs and underground aquifers are proposed candidates for carbon dioxide injection. This paper presented an experimental investigation into the reactive transport module for handling aquifer sequestration of carbon dioxide and modeling of simultaneous geochemical reactions. Two cases of laboratory carbon dioxide sequestration experiments, conducted for different rock systems were modeled using the fully coupled geochemical compositional simulator. The relevant permeability relationships were compared to determine the best fit with the experimental results. The paper discussed the theory of modeling; geochemical reactions and mineral trapping of carbon dioxide; and application simulator for modeling including the remodeling of flow experiments. It was concluded that simulated changes in porosity and permeability could mimic experimental results to some extent. The study satisfactorily simulated the results of experimental observations and permeability results could be improved if the Kozeny-Carman equation was replaced by the Civan power law. 6 refs., 2 tabs., 21 figs.

  9. Performance analysis of a novel energy storage system based on liquid carbon dioxide

    International Nuclear Information System (INIS)

    Wang, Mingkun; Zhao, Pan; Wu, Yi; Dai, Yiping

    2015-01-01

    Due to the intermittence and fluctuation of wind resource, the increasing penetration level of wind power will bring huge challenges to maintain the stability of power system. Integrating compressed air energy storage (CAES) system with wind farms can weaken this negative effect. However CAES system needs large caverns or mines to store compressed air, which is restricted in application. In this paper, a novel energy storage system based on liquid carbon dioxide is presented. The mathematical models of compressed liquid-carbon dioxide energy storage system are developed. The parametric analysis is conducted to examine the effect of some key thermodynamic parameters on the system performance. Compared with AA-CAES, the liquid carbon dioxide energy storage system has advantages such as a high energy density, high EVR. Moreover, the round trip efficiency of this system can reach about 56.64%, which is acceptable in consideration of the storage volume. Therefore, this proposed system has a good potential for storing wind power in large scale and offers an attractive solution to the challenges of the increasing penetration level of wind power. - Highlights: • A novel energy storage system based on liquid carbon dioxide is presented. • The effects of some key parameters on the system performance are studied. • The operation optimization is conducted by genetic algorithm. • Comparative analysis of AA-CAES and liquid carbon dioxide system is studied.

  10. Electric Utility Generating Units: Repealing the Clean Power Plan

    Science.gov (United States)

    The Clean Power Plan established emission guidelines for states to follow in limiting carbon dioxide (CO2) emissions from existing power plants. EPA is proposing to repeal the CPP and rescind the accompanying legal memorandum.

  11. Carbon dioxide capture processes: Simulation, design and sensitivity analysis

    DEFF Research Database (Denmark)

    Zaman, Muhammad; Lee, Jay Hyung; Gani, Rafiqul

    2012-01-01

    equilibrium and associated property models are used. Simulations are performed to investigate the sensitivity of the process variables to change in the design variables including process inputs and disturbances in the property model parameters. Results of the sensitivity analysis on the steady state...... performance of the process to the L/G ratio to the absorber, CO2 lean solvent loadings, and striper pressure are presented in this paper. Based on the sensitivity analysis process optimization problems have been defined and solved and, a preliminary control structure selection has been made.......Carbon dioxide is the main greenhouse gas and its major source is combustion of fossil fuels for power generation. The objective of this study is to carry out the steady-state sensitivity analysis for chemical absorption of carbon dioxide capture from flue gas using monoethanolamine solvent. First...

  12. Steam generators for nuclear power plants

    International Nuclear Information System (INIS)

    Tillequin, Jean

    1975-01-01

    The role and the general characteristics of steam generators in nuclear power plants are indicated, and particular types are described according to the coolant nature (carbon dioxide, helium, light water, heavy water, sodium) [fr

  13. Flue gas injection into gas hydrate reservoirs for methane recovery and carbon dioxide sequestration

    International Nuclear Information System (INIS)

    Yang, Jinhai; Okwananke, Anthony; Tohidi, Bahman; Chuvilin, Evgeny; Maerle, Kirill; Istomin, Vladimir; Bukhanov, Boris; Cheremisin, Alexey

    2017-01-01

    Highlights: • Flue gas was injected for both methane recovery and carbon dioxide sequestration. • Kinetics of methane recovery and carbon dioxide sequestration was investigated. • Methane-rich gas mixtures can be produced inside methane hydrate stability zones. • Up to 70 mol% of carbon dioxide in the flue gas was sequestered as hydrates. - Abstract: Flue gas injection into methane hydrate-bearing sediments was experimentally investigated to explore the potential both for methane recovery from gas hydrate reservoirs and for direct capture and sequestration of carbon dioxide from flue gas as carbon dioxide hydrate. A simulated flue gas from coal-fired power plants composed of 14.6 mol% carbon dioxide and 85.4 mol% nitrogen was injected into a silica sand pack containing different saturations of methane hydrate. The experiments were conducted at typical gas hydrate reservoir conditions from 273.3 to 284.2 K and from 4.2 to 13.8 MPa. Results of the experiments show that injection of the flue gas leads to significant dissociation of the methane hydrate by shifting the methane hydrate stability zone, resulting in around 50 mol% methane in the vapour phase at the experimental conditions. Further depressurisation of the system to pressures well above the methane hydrate dissociation pressure generated methane-rich gas mixtures with up to 80 mol% methane. Meanwhile, carbon dioxide hydrate and carbon dioxide-mixed hydrates were formed while the methane hydrate was dissociating. Up to 70% of the carbon dioxide in the flue gas was converted into hydrates and retained in the silica sand pack.

  14. 21 CFR 184.1240 - Carbon dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Carbon dioxide. 184.1240 Section 184.1240 Food and... Substances Affirmed as GRAS § 184.1240 Carbon dioxide. (a) Carbon dioxide (empirical formula CO2, CAS Reg. No.... The solid form, dry ice, sublimes under atmospheric pressure at a temperature of −78.5 °C. Carbon...

  15. A METHOD OF PREPARING URANIUM DIOXIDE

    Science.gov (United States)

    Scott, F.A.; Mudge, L.K.

    1963-12-17

    A process of purifying raw, in particular plutonium- and fission- products-containing, uranium dioxide is described. The uranium dioxide is dissolved in a molten chloride mixture containing potassium chloride plus sodium, lithium, magnesium, or lead chloride under anhydrous conditions; an electric current and a chlorinating gas are passed through the mixture whereby pure uranium dioxide is deposited on and at the same time partially redissolved from the cathode. (AEC)

  16. Carbon dioxide sequestration by aqueous mineral carbonation of magnesium silicate minerals

    Energy Technology Data Exchange (ETDEWEB)

    Gerdemann, Stephen J.; Dahlin, David C.; O' Connor, William K.; Penner, Larry R.

    2003-01-01

    The dramatic increase in atmospheric carbon dioxide since the Industrial Revolution has caused concerns about global warming. Fossil-fuel-fired power plants contribute approximately one third of the total human-caused emissions of carbon dioxide. Increased efficiency of these power plants will have a large impact on carbon dioxide emissions, but additional measures will be needed to slow or stop the projected increase in the concentration of atmospheric carbon dioxide. By accelerating the naturally occurring carbonation of magnesium silicate minerals it is possible to sequester carbon dioxide in the geologically stable mineral magnesite (MgCO3). The carbonation of two classes of magnesium silicate minerals, olivine (Mg2SiO4) and serpentine (Mg3Si2O5(OH)4), was investigated in an aqueous process. The slow natural geologic process that converts both of these minerals to magnesite can be accelerated by increasing the surface area, increasing the activity of carbon dioxide in the solution, introducing imperfections into the crystal lattice by high-energy attrition grinding, and in the case of serpentine, by thermally activating the mineral by removing the chemically bound water. The effect of temperature is complex because it affects both the solubility of carbon dioxide and the rate of mineral dissolution in opposing fashions. Thus an optimum temperature for carbonation of olivine is approximately 185 degrees C and 155 degrees C for serpentine. This paper will elucidate the interaction of these variables and use kinetic studies to propose a process for the sequestration of the carbon dioxide.

  17. Combined effect of sulfur dioxide and carbon dioxide gases on mold fungi

    Energy Technology Data Exchange (ETDEWEB)

    Kochurova, A.I.; Karpova, T.N.

    1974-01-01

    Sulfur dioxide at 0.08% killed Penicillium expansum, Stemphylium macrosporium, and Botrytis cinerea within 24 hours. At 0.2%, it killed P. citrinum, Alternaria tenuis, and Fusarium moniliforme. Sulfur dioxide (at 0.04%) and Sulfur dioxide-carbon dioxide mixtures (at 0.02 and 5% respectively) completely suppressed the growth of P. citrinum, P. expansum, P. rubrum, A. tenuis, S. macrosporium, B. cinerea, and F. moniliforme in laboratory experiments. 1 table.

  18. Experimental nitrogen dioxide poisoning in cattle

    Energy Technology Data Exchange (ETDEWEB)

    Cutlip, R C

    1966-01-01

    Experimental nitrogen dioxide inhalation has been reported to produce signs and lesions typical of field cases of bovine pulmonary adenomatosis (BPA) as described by Monlux et al, and Seaton. Similar lesions have been produced in mice and guinea pigs. These studies were conducted because of the similarities between silo-filler's disease of man, caused by nitrogen dioxide, and BPA. Since previous studies involved inadequate numbers of cattle, a more critical evaluation of the effects of nitrogen dioxide was needed. This project was designed to study the clinical and pathologic alterations induced in cattle by repeated exposure to nitrogen dioxide gas.

  19. Titanium dioxide nanomaterials for photocatalysis

    International Nuclear Information System (INIS)

    Liu, Yan; Li, Zhe; Green, Michael; Just, Michael; Chen, Xiaobo; Li, Yang Yang

    2017-01-01

    Titanium dioxide (TiO 2 ) has been long regarded as one of the more promising photocatalysts to remove environmental pollution and to generate hydrogen from water under sunlight irradiation via photocatalysis. TiO 2 is environmentally benign and thus is considered a ‘green’ catalyst. In this review we present a short introduction to the physical and electronic properties of TiO 2 , its photocatalytic mechanisms, and some recent examples of various TiO 2 materials used for photocatalysis; these examples include 0, 1, 2, 3D, faceted, defected, composited, and hydrogenated TiO 2 materials. (topical review)

  20. Muon transfer to sulphur dioxide

    International Nuclear Information System (INIS)

    Mulhauser, F.; Schneuwly, H.

    1993-01-01

    A systematic study of muon capture and muon transfer has been performed in seven different H 2 + SO 2 gas mixtures. From the single-exponential time structure of the muonic sulphur x-rays, one determines the lifetime of the μp atoms under the given experimental conditions. The reduced muon transfer rates to the sulphur dioxide molecule, deduced from these lifetimes, all agree well with each other. The muonic oxygen time spectra show an additional structure as if μp atoms of another kind were present. Comparable time structures are observed in a D 2 + SO 2 mixture. (author)

  1. PRELIMINARY ENVIRONMENTAL, HEALTH AND SAFETY RISK ASSESSMENT ON THE INTEGRATION OF A PROCESS UTILIZING LOW-ENERGY SOLVENTS FOR CARBON DIOXIDE CAPTURE ENABLED BY A COMBINATION OF ENZYMES AND VACUUM REGENERATION WITH A SUBCRITICAL PC POWER PLANT

    Energy Technology Data Exchange (ETDEWEB)

    Fitzgerald, David; Vidal, Rafael; Russell, Tania; Babcock, Doosan; Freeman, Charles; Bearden, Mark; Whyatt, Greg; Liu, Kun; Frimpong, Reynolds; Lu, Kunlei; Salmon, Sonja; House, Alan; Yarborough, Erin

    2014-12-31

    The results of the preliminary environmental, health and safety (EH&S) risk assessment for an enzyme-activated potassium carbonate (K2CO3) solution post-combustion CO2 capture (PCC) plant, integrated with a subcritical pulverized coal (PC) power plant, are presented. The expected emissions during normal steady-state operation have been estimated utilizing models of the PCC plant developed in AspenTech’s AspenPlus® software, bench scale test results from the University of Kentucky, and industrial experience of emission results from a slipstream PCC plant utilizing amine based solvents. A review of all potential emission species and their sources was undertaken that identified two credible emission sources, the absorber off-gas that is vented to atmosphere via a stack and the waste removed from the PCC plant in the centrifuge used to reclaim enzyme and solvent. The conditions and compositions of the emissions were calculated and the potential EH&S effects were considered as well as legislative compliance requirements. Potential mitigation methods for emissions during normal operation have been proposed and solutions to mitigate uncontrolled releases of species have been considered. The potential emissions were found to pose no significant EH&S concerns and were compliant with the Federal legislation reviewed. The limitations in predicting full scale plant performance from bench scale tests have been noted and further work on a larger scale test unit is recommended to reduce the level of uncertainty.

  2. Fuel saving, carbon dioxide emission avoidance, and syngas production by tri-reforming of flue gases from coal- and gas-fired power stations, and by the carbothermic reduction of iron oxide

    International Nuclear Information System (INIS)

    Halmann, M.; Steinfeld, A.

    2006-01-01

    Flue gases from coal, gas, or oil-fired power stations, as well as from several heavy industries, such as the production of iron, lime and cement, are major anthropogenic sources of global CO 2 emissions. The newly proposed process for syngas production based on the tri-reforming of such flue gases with natural gas could be an important route for CO 2 emission avoidance. In addition, by combining the carbothermic reduction of iron oxide with the partial oxidation of the carbon source, an overall thermoneutral process can be designed for the co-production of iron and syngas rich in CO. Water-gas shift (WGS) of CO to H 2 enables the production of useful syngas. The reaction process heat, or the conditions for thermoneutrality, are derived by thermochemical equilibrium calculations. The thermodynamic constraints are determined for the production of syngas suitable for methanol, hydrogen, or ammonia synthesis. The environmental and economic consequences are assessed for large-scale commercial production of these chemical commodities. Preliminary evaluations with natural gas, coke, or coal as carbon source indicate that such combined processes should be economically competitive, as well as promising significant fuel saving and CO 2 emission avoidance. The production of ammonia in the above processes seems particularly attractive, as it consumes the nitrogen in the flue gases

  3. Effect of Novel Quercetin Titanium Dioxide-Decorated Multi-Walled Carbon Nanotubes Nanocomposite on Bacillus subtilis Biofilm Development

    Directory of Open Access Journals (Sweden)

    Diana S. Raie

    2018-01-01

    Full Text Available The present work was targeted to design a surface against cell seeding and adhering of bacteria, Bacillus subtilis. A multi-walled carbon nanotube/titanium dioxide nano-power was produced via simple mixing of carbon nanotube and titanium dioxide nanoparticles during the sol-gel process followed by heat treatment. Successfully, quercetin was immobilized on the nanocomposite via physical adsorption to form a quercetin/multi-walled carbon nanotube/titanium dioxide nanocomposite. The adhesion of bacteria on the coated-slides was verified after 24 h using confocal laser-scanning microscopy. Results indicated that the quercetin/multi-walled carbon nanotube/titanium dioxide nanocomposite had more negativity and higher recovery by glass surfaces than its counterpart. Moreover, coating surfaces with the quercetin-modified nanocomposite lowered both hydrophilicity and surface-attached bacteria compared to surfaces coated with the multi-walled carbon nanotubes/titanium dioxide nanocomposite.

  4. The effects of changes in the UK energy demand and environmental legislation on atmospheric pollution by carbon dioxide

    International Nuclear Information System (INIS)

    Blakemore, F.B.; Davies, C.; Isaac, J.G.

    1998-01-01

    It has been demonstrated that the combustion of fossil fuel accounts for 97% of the carbon dioxide generated in the UK. The demand for primary energy over the 1970-1994 period has only marginally increased, however the demand for natural gas, which has a significantly lower carbon content per unit of energy than other fuels, accounts largely for the lowering of carbon dioxide emissions. The enactment UK/EU Environmental Legislation coupled with World Agreements accounts for a significant lowering of carbon dioxide emissions over this period. Future predictions suggest that a further downturn in carbon dioxide emissions will take place over the 1990-2000 period, followed by a pronounced increase over the 2000-2020 period. The expansion of the use of CCGT and/or the introduction of the IGCC and the SUPC in the power generating sector provides an opportunity for a further reduction in carbon dioxide emissions. (author)

  5. Sulfur Dioxide Analyzer Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Springston, Stephen R. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-05-01

    The Sulfur Dioxide Analyzer measures sulfur dioxide based on absorbance of UV light at one wavelength by SO2 molecules which then decay to a lower energy state by emitting UV light at a longer wavelength. Specifically, SO2 + hυ1 →SO2 *→SO2 + hυ2 The emitted light is proportional to the concentration of SO2 in the optical cell. External communication with the analyzer is available through an Ethernet port configured through the instrument network of the AOS systems. The Model 43i-TLE is part of the i-series of Thermo Scientific instruments. The i-series instruments are designed to interface with external computers through the proprietary Thermo Scientific iPort Software. However, this software is somewhat cumbersome and inflexible. Brookhaven National Laboratory (BNL) has written an interface program in National Instruments LabView that both controls the Model 43i-TLE Analyzer AND queries the unit for all measurement and housekeeping data. The LabView vi (the software program written by BNL) ingests all raw data from the instrument and outputs raw data files in a uniform data format similar to other instruments in the AOS and described more fully in Section 6.0 below.

  6. The Lancet Countdown on PM2·5 pollution-related health impacts of China's projected carbon dioxide mitigation in the electric power generation sector under the Paris Agreement: a modelling study

    Directory of Open Access Journals (Sweden)

    Wenjia Cai, PhD

    2018-04-01

    Full Text Available Summary: Background: Except for comparing the implementation costs of the Paris Agreement with potential health benefits at the national levels, previous studies have not explored the health impacts of the nationally determined contributions (NDCs by countries and in regional details. In this Lancet Countdown study, we aimed to estimate and monetise the health benefits of China's NDCs in the electric power generation sector, and then compare them with the implementation costs, both at the national and regional levels. Methods: In this modelling study, we linked the Multi-regional model for Energy Supply system and their Environmental ImpaCts, the Multi-resolution Emission Inventory for China model, the offline-coupled Weather Research and Forecasting model, the Community Multiscale Air Quality model, and the Integrated Health Impact Assessment model with a time scope from 2010 to 2050. We calculated the PM2·5 concentrations and compared the health impacts and implementation costs between two scenarios that reflect CO2 and air pollutant emissions—the reference (REF scenario (no climate policy and the NDC scenario (100% realisation of NDC targets: CO2 emission intensity needs to be about 40% below 2010 emissions by 2030 [roughly 35% below 2030 emissions in REF], and about 90% below 2010 emissions by 2050 [roughly 96% below 2050 emissions in REF]. Findings: Under a comparatively optimistic health benefits valuation condition, at the national level, 18–62% of implementation costs could be covered by the health benefits in 2030. In 2050, the overall health benefits would substantially increase to 3–9 times of the implementation costs. However, northwest China would require the highest implementation costs and will also have more premature deaths because of a more carbon-intensive energy structure than business as usual. By 2030, people in northwest China (especially in Gansu, Shaanxi, and Xinjiang provinces would need to bear worse air quality

  7. Demonstration of a Variable Phase Turbine Power System for Low Temperature Geothermal Resources

    Energy Technology Data Exchange (ETDEWEB)

    Hays, Lance G

    2014-07-07

    A variable phase turbine assembly will be designed and manufactured having a turbine, operable with transcritical, two-phase or vapor flow, and a generator – on the same shaft supported by process lubricated bearings. The assembly will be hermetically sealed and the generator cooled by the refrigerant. A compact plate-fin heat exchanger or tube and shell heat exchanger will be used to transfer heat from the geothermal fluid to the refrigerant. The demonstration turbine will be operated separately with two-phase flow and with vapor flow to demonstrate performance and applicability to the entire range of low temperature geothermal resources. The vapor leaving the turbine is condensed in a plate-fin refrigerant condenser. The heat exchanger, variable phase turbine assembly and condenser are all mounted on single skids to enable factory assembly and checkout and minimize installation costs. The system will be demonstrated using low temperature (237F) well flow from an existing large geothermal field. The net power generated, 1 megawatt, will be fed into the existing power system at the demonstration site. The system will demonstrate reliable generation of inexpensive power from low temperature resources. The system will be designed for mass manufacturing and factory assembly and should cost less than $1,200/kWe installed, when manufactured in large quantities. The estimated cost of power for 300F resources is predicted to be less than 5 cents/kWh. This should enable a substantial increase in power generated from low temperature geothermal resources.

  8. Carbon Dioxide for pH Control

    Energy Technology Data Exchange (ETDEWEB)

    Wagonner, R.C.

    2001-08-16

    Cardox, the major supplier of carbon dioxide, has developed a diffuser to introduce carbon dioxide into a water volume as small bubbles to minimize reagent loss to the atmosphere. This unit is integral to several configurations suggested for treatment to control alkalinity in water streams.

  9. Carbon dioxide sequestration by mineral carbonation

    NARCIS (Netherlands)

    Huijgen, W.J.J.

    2007-01-01

    The increasing atmospheric carbon dioxide (CO2) concentration, mainly caused by fossil fuel combustion, has lead to concerns about global warming. A possible technology that can contribute to the reduction of carbon dioxide emissions is CO2 sequestration by mineral carbonation. The basic concept

  10. Trading coalbed methane for carbon dioxide

    International Nuclear Information System (INIS)

    Greenberger, L.S.

    1991-01-01

    This article discusses a proposal for reducing methane emissions in coal mining activities and at the same time reducing the burden on utilities to cut carbon dioxide emissions. Emission credits would be issued to mines that recover the methane for use. These credits could then be bought by utilities and exchanged for the right to emit carbon dioxide

  11. Pressure pumping of carbon dioxide from soil

    Science.gov (United States)

    E. S. Takle; J. R. Brandle; R. A. Schmidt; R. Garcia; I. V. Litvina; G. Doyle; X. Zhou; Q. Hou; C. W. Rice; W. J. Massman

    2000-01-01

    Recent interest in atmospheric increases in carbon dioxide have heightened the need for improved accuracy in measurements of fluxes of carbon dioxide from soils. Diffusional movement has long been considered the dominant process by which trace gases move from the subsurface source to the surface, although there has been some indication that atmospheric pressure...

  12. Process for the preparation of uranium dioxide

    International Nuclear Information System (INIS)

    Watt, G.W.; Baugh, D.W. Jr.

    1981-01-01

    A method for the preparation of actinide dioxides using actinide nitrate hexahydrates as starting materials is described. The actinide nitrate hexahydrate is reacted with sodium dithionite, and the product is heated in the absence of oxygen to obtain the dioxide. Preferably, the actinide is uranium, plutonium or neptunium. (LL)

  13. Thermoexpanded graphite modification by titanium dioxide

    International Nuclear Information System (INIS)

    Semko, L.S.; Gorbik, P.P.; Chujko, O.O.; Kruchek, Ya.Yi.; Dzyubenko, L.S.; Orans'ka, O.Yi.

    2006-01-01

    A method of the synthesis of thermoexpanded graphite (TEG) powders coated by titanium dioxide is developed. The conversion of n-buthylorthotitanate into TiO 2 on the TEG surface is investigated. The optimal parameters of the synthesis and the structure of titanium dioxide clusters on the TEG surface are determined

  14. The Lancet Countdown on PM2·5 pollution-related health impacts of China's projected carbon dioxide mitigation in the electric power generation sector under the Paris Agreement: a modelling study.

    Science.gov (United States)

    Cai, Wenjia; Hui, Jingxuan; Wang, Can; Zheng, Yixuan; Zhang, Xin; Zhang, Qiang; Gong, Peng

    2018-04-01

    Except for comparing the implementation costs of the Paris Agreement with potential health benefits at the national levels, previous studies have not explored the health impacts of the nationally determined contributions (NDCs) by countries and in regional details. In this Lancet Countdown study, we aimed to estimate and monetise the health benefits of China's NDCs in the electric power generation sector, and then compare them with the implementation costs, both at the national and regional levels. In this modelling study, we linked the Multi-regional model for Energy Supply system and their Environmental ImpaCts, the Multi-resolution Emission Inventory for China model, the offline-coupled Weather Research and Forecasting model, the Community Multiscale Air Quality model, and the Integrated Health Impact Assessment model with a time scope from 2010 to 2050. We calculated the PM 2·5 concentrations and compared the health impacts and implementation costs between two scenarios that reflect CO 2 and air pollutant emissions-the reference (REF) scenario (no climate policy) and the NDC scenario (100% realisation of NDC targets: CO 2 emission intensity needs to be about 40% below 2010 emissions by 2030 [roughly 35% below 2030 emissions in REF], and about 90% below 2010 emissions by 2050 [roughly 96% below 2050 emissions in REF]). Under a comparatively optimistic health benefits valuation condition, at the national level, 18-62% of implementation costs could be covered by the health benefits in 2030. In 2050, the overall health benefits would substantially increase to 3-9 times of the implementation costs. However, northwest China would require the highest implementation costs and will also have more premature deaths because of a more carbon-intensive energy structure than business as usual. By 2030, people in northwest China (especially in Gansu, Shaanxi, and Xinjiang provinces) would need to bear worse air quality, and 10 083 (95% CI 3419-16 138) more premature

  15. Behavior of ion-implanted cesium in silicon dioxide films

    International Nuclear Information System (INIS)

    Fishbein, B.J.

    1988-01-01

    Charged impurities in silicon dioxide can be used to controllably shift the flatband voltage of metal-oxide-semiconductor devices independently of the substrate doping, the gate oxide thickness and the gate-electrode work function. Cesium is particularly well suited for this purpose because it is immobile in SiO 2 at normal device operating temperatures, and because it can be controllably introduced into oxide films by ion implantation. Cesium is positively charged in silicon dioxide, resulting in a negative flatband voltage shift. Possible applications for cesium technology include solar cells, devices operated at liquid nitrogen temperature, and power devices. The goal of this work has been to characterize as many aspects of cesium behavior in silicon dioxide as are required for practical applications. Accordingly, cesium-ion implantation, cesium diffusion, and cesium electrical activation in SiO 2 were studied over a broad range of processing conditions. The electrical properties of cesium-containing oxides, including current-voltage characteristics, interface trap density, and inversion-layer carrier mobility were examined, and several potential applications for cesium technology have been experimentally demonstrated

  16. Balance of emissions and consumptions of carbon dioxide in Spain

    International Nuclear Information System (INIS)

    Valero, A.; Subiela, V.; Cortes, C.

    1994-01-01

    The amount of carbon dioxide in atmosphere increase due to deforestation and anthropogenic emissions. The consumption of this gas in vegetal ecosystems must also be considered to know the net mass of CO 2 that gets into the atmosphere. This article summarizes the methodology, results and conclusions of the carbon dioxide balance in Spain by autonomous communities. The different fossil fuel consumer sectors (Thermal power plants, industry, transport, domestic and agricultural), forest biomass reduction due to fires and wood extractions for firewood are considered as sources. As sinks, natural and reforested forests, and the equivalent sea are noticed. Basically, the article presents a new methodology to estimate carbon dioxide consumption in forest biomass. The average emissions for 1981 to 1990 are presented. A per capita value of 5 t(CO 2 /year is obtained in contrast to the EC average of 8,6 t(CO 2 ) year. The resulting net balance shows that it is only consumed between 20 and 50% of the emitted CO 2 . (Author) 47 refs

  17. Modeling the dynamics of carbon dioxide removal in the atmosphere

    Directory of Open Access Journals (Sweden)

    Shyam Sundar

    2014-12-01

    Full Text Available The temperature of Earth's surface is increasing over the past few years due to emission of global warming gases such as CO2, CH4 and NOx from industries, power plants, etc., leading to several adverse effects on human and his environment. Therefore, the question of their removal/reduction from the atmosphere is very important. In this paper, a nonlinear mathematical model to study the removal/reduction of carbon dioxide by using suitable absorbent (such as aqueous ammonia solution, amines, sodium hydroxide, etc. near the source of emission and externally introducing liquid species in the atmosphere is presented. Dynamical properties of the model which include local and global stabilities for the equilibrium are analyzed carefully. Model analysis is performed by considering three physical situations i.e. when both absorbent and the liquid species are used, only absorbent is used and only liquid species is used. It is shown that the concentration of carbon dioxide decreases as the rate of introduction of absorbent in the absorber increases. It decreases further as the rate of introduction of liquid species. Thus, the concentration of carbon dioxide would be reduced by a large amount if adequate amount of absorbent is used near the source of emission. The remaining amount can be reduced further by infusing liquid drops in the atmosphere. Numerical simulations are also carried out to support the analytical results.

  18. Heat and power from combustibles

    International Nuclear Information System (INIS)

    Zogg, M.

    2002-01-01

    This article compares four ways of generating heat and power from liquid and gaseous fuels. Various combinations of conventional boilers, heat pumps, combined heat and power units and combined-cycle power plants are considered and the ratio of heat to electrical power produced is discussed. Fuel requirements for the four combinations are looked at and net emissions of carbon dioxide, oxides of nitrogen and carbon monoxide presented in graphical form. The author makes recommendations on the choice of the technology to be used to generate heat and electricity for different heat/power ratios and criticises the all too slack emission limits for small combined heat and power units

  19. Carbon dioxide production in animal houses

    DEFF Research Database (Denmark)

    Pedersen, Søren; Blanes-Vidal, Victoria; Joergensen, H.

    2008-01-01

    cellars are emptied regularly in a four weeks interval. Due to a high and variable carbon dioxide production in deep straw litter houses and houses with indoor storage of manure longer than four weeks, we do not recommend to calculate the ventilation flow based on the carbon dioxide concentration......This article deals with carbon dioxide production from farm animals; more specifically, it addresses the possibilities of using the measured carbon dioxide concentration in animal houses as basis for estimation of ventilation flow (as the ventilation flow is a key parameter of aerial emissions from...... animal houses). The investigations include measurements in respiration chambers and in animal houses, mainly for growing pigs and broilers. Over the last decade a fixed carbon dioxide production of 185 litres per hour per heat production unit, hpu (i.e. 1000 W of the total animal heat production at 20o...

  20. Incentives of carbon dioxide regulation for investment in low-carbon electricity technologies in Texas

    International Nuclear Information System (INIS)

    Castillo, Anya; Linn, Joshua

    2011-01-01

    This paper compares the incentives a carbon dioxide emissions price creates for investment in low carbon dioxide-emitting technologies in the electricity sector. We consider the extent to which operational differences across generation technologies - particularly, nuclear, wind and solar photovoltaic - create differences in the incentives for new investment, which is measured by the operating profits of a potential entrant. First, astylized model of an electricity system demonstrates that the composition of the existing generation system may cause electricity prices to increase by different amounts over time when a carbon dioxide price is imposed. Differences in operation across technologies therefore translate to differences in the operating profits of a potential entrant. Then, a detailed simulation model is used to consider a hypothetical carbon dioxide price of $10-$50 per metric ton for the Electric Reliability Council of Texas (ERCOT) market. The simulations show that, for the range of prices considered, the increase in electricity prices is positively correlated with output from a typical wind unit, but the correlation is much weaker for nuclear and photovoltaic. Consequently, a carbon dioxide price creates much stronger investment incentives for wind than for nuclear or photovoltaic technologies in the Texas market. - Highlights: → Compare incentives for new investment in low-emission electricity technologies created by carbon dioxide price. → Focus on ERCOT power system using stochastic unit commitment model. →Find a greater incentive for wind than solar or nuclear because of correlation between wind generation and increase in electricity prices.

  1. Environmental cables may provide electricity without carbon dioxide

    International Nuclear Information System (INIS)

    Nedrelid, Ola N.

    2005-01-01

    It is asserted in this article that a large-scale development of cables between Norway and the Continent may have such large environmental advantages that it will greatly affect the future energy and environmental policy in Norway. Preliminary figures show that by interaction of Norwegian hydropower and European thermal power the reduction in CO 2 emission may amount to more than 6 million tonnes per year. This corresponds to Norway's Kyoto commitment. It is not always realized that when the thermal power stations must continuously adjust production in step with consumption then the efficiency is strongly reduced. The fuel consumption rises and so does the emission of carbon dioxide per kWh. Hydropower plants can easily take these load variations, and then the thermal power stations will be able to run more evenly which strongly increases efficiency and cuts the CO 2 emissions to the environment

  2. Fusion Power Deployment

    International Nuclear Information System (INIS)

    Schmidt, J.A.; Ogden, J.M.

    2002-01-01

    Fusion power plants could be part of a future portfolio of non-carbon dioxide producing energy supplies such as wind, solar, biomass, advanced fission power, and fossil energy with carbon dioxide sequestration. In this paper, we discuss key issues that could impact fusion energy deployment during the last half of this century. These include geographic issues such as resource availability, scale issues, energy storage requirements, and waste issues. The resource needs and waste production associated with fusion deployment in the U.S. should not pose serious problems. One important feature of fusion power is the fact that a fusion power plant should be locatable within most local or regional electrical distribution systems. For this reason, fusion power plants should not increase the burden of long distance power transmission to our distribution system. In contrast to fusion power, regional factors could play an important role in the deployment of renewable resources such as wind, solar and biomass or fossil energy with CO2 sequestration. We examine the role of these regional factors and their implications for fusion power deployment

  3. Aspect of nuclear power

    International Nuclear Information System (INIS)

    Haghighi Oskoei, R.; Raeis Hosseiny, N.

    2004-01-01

    Over the next 50 years, unless patterns change dramatically, energy production and use will contribute to global warming through large-scale greenhouse gas emissions-hundreds of billions of tonnes of carbon in the form of carbon dioxide. Nuclear power would be one option for reducing carbon emissions. At present, however, this is unlikely: nuclear power faces stagnation and decline. We decided to study the future of nuclear power because we believe this technology , despite the changes it faces, is an important option for the world to meet future energy needs without emitting carbon dioxide and other atmospheric pollutants. Other options include increased efficiency, renewable and sequestration. We believe that all options should be preserved as nations develop strategies at provide energy while meeting important environmental challenges. The nuclear power option will only be exercised, however if the technology demonstrates better economics, improved safety, successful waste management, and low proliferation risk, and if public policies place a significant value on electricity production that does not produce carbon dioxide

  4. Forest response to carbon dioxide

    International Nuclear Information System (INIS)

    Pitelka, L.

    1992-01-01

    It has been suggested that planting trees could help slow the buildup of carbon dioxide in the atmosphere. Since elevated levels of CO 2 are known to enhance photosynthesis and growth in many plants, it is possible that trees could become progressively more effective in storing carbon as atmospheric CO 2 increases. However, early results from experiments with ponderosa and loblolly pines indicate that the relationship between tree growth and rising CO 2 concentrations may be more complex than scientists once thought. In these experiments, the response to elevated CO 2 has been highly dependent both on species and on mineral nutrient levels in the soil. Further work is necessary to clarify the mechanisms involved. This research will ultimately contribute to an integrated model for predicting forest ecosystem response to elevated CO 2

  5. Electrochemical processing of carbon dioxide.

    Science.gov (United States)

    Oloman, Colin; Li, Hui

    2008-01-01

    With respect to the negative role of carbon dioxide on our climate, it is clear that the time is ripe for the development of processes that convert CO(2) into useful products. The electroreduction of CO(2) is a prime candidate here, as the reaction at near-ambient conditions can yield organics such as formic acid, methanol, and methane. Recent laboratory work on the 100 A scale has shown that reduction of CO(2) to formate (HCO(2)(-)) may be carried out in a trickle-bed continuous electrochemical reactor under industrially viable conditions. Presuming the problems of cathode stability and formate crossover can be overcome, this type of reactor is proposed as the basis for a commercial operation. The viability of corresponding processes for electrosynthesis of formate salts and/or formic acid from CO(2) is examined here through conceptual flowsheets for two process options, each converting CO(2) at the rate of 100 tonnes per day.

  6. Nongovernmental valorization of carbon dioxide

    International Nuclear Information System (INIS)

    Petersen, Gene; Viviani, Donn; Magrini-Bair, Kim; Kelley, Stephen; Moens, Luc; Shepherd, Phil; DuBois, Dan

    2005-01-01

    Carbon dioxide (CO 2 ) is considered the largest contributor to the greenhouse gas effect. Most attempts to manage the flow of CO 2 or carbon into our environment involve reducing net emissions or sequestering the gas into long-lived sinks. Using CO 2 as a chemical feedstock has a long history, but using it on scales that might impact the net emissions of CO 2 into the atmosphere has not generally been considered seriously. There is also a growing interest in employing our natural biomes of carbon such as trees, vegetation, and soils as storage media. Some amelioration of the net carbon emissions into the atmosphere could be achieved by concomitant large withdrawals of carbon. This report surveys the potential and limitations in employing carbon as a resource for organic chemicals, fuels, inorganic materials, and in using the biome to manage carbon. The outlook for each of these opportunities is also described

  7. Erbium diffusion in titanium dioxide

    Directory of Open Access Journals (Sweden)

    Louise Basse

    2017-04-01

    Full Text Available The diffusivity of erbium in the anatase phase of titanium dioxide (TiO2 has been studied for various temperatures ranging from 800 °C to 1, 000 °C. Samples of TiO2, with a 10 nm thick buried layer containing 0.5 at% erbium, were fabricated by radio-frequency magnetron sputtering and subsequently heat treated. The erbium concentration profiles were measured by secondary ion mass spectrometry, allowing for determination of the temperature-dependent diffusion coefficients. These were found to follow an Arrhenius law with an activation energy of ( 2.1 ± 0.2 eV. X-ray diffraction revealed that the TiO2 films consisted of polycrystalline grains of size ≈ 100 nm.

  8. Carbon dioxide cleaning pilot project

    International Nuclear Information System (INIS)

    Knight, L.; Blackman, T.E.

    1994-01-01

    In 1989, radioactive-contaminated metal at the Rocky Flats Plant (RFP) was cleaned using a solvent paint stripper (Methylene chloride). One-third of the radioactive material was able to be recycled; two-thirds went to the scrap pile as low-level mixed waste. In addition, waste solvent solutions also required disposal. Not only was this an inefficient process, it was later prohibited by the Resource Conservation and Recovery Act (RCRA), 40 CFR 268. A better way of doing business was needed. In the search for a solution to this situation, it was decided to study the advantages of using a new technology - pelletized carbon dioxide cleaning. A proof of principle demonstration occurred in December 1990 to test whether such a system could clean radioactive-contaminated metal. The proof of principle demonstration was expanded in June 1992 with a pilot project. The purpose of the pilot project was three fold: (1) to clean metal so that it can satisfy free release criteria for residual radioactive contamination at the Rocky Flats Plant (RFP); (2) to compare two different carbon dioxide cleaning systems; and (3) to determine the cost-effectiveness of decontamination process in a production situation and compare the cost of shipping the metal off site for waste disposal. The pilot project was completed in August 1993. The results of the pilot project were: (1) 90% of those items which were decontaminated, successfully met the free release criteria , (2) the Alpheus Model 250 was selected to be used on plantsite and (3) the break even cost of decontaminating the metal vs shipping the contaminated material offsite for disposal was a cleaning rate of 90 pounds per hour, which was easily achieved

  9. Computational Modeling of Supercritical and Transcritical Flows

    Science.gov (United States)

    2017-01-09

    Acentric factor I. Introduction Liquid rocket and gas turbine engines operate at high pressures . For gas turbines, the combustor pressurecan be 60 − 100...equation of state for several reduced pressures . The model captures the high density at very low temperatures and the supercritical behavior at high reduced...physical meaning. The temperature range over which the three roots are present is bounded by TL on the low side and TH on the high side. Figure 2: Roots

  10. Nanoparticulate cerium dioxide and cerium dioxide-titanium dioxide composite thin films on glass by aerosol assisted chemical vapour deposition

    International Nuclear Information System (INIS)

    Qureshi, Uzma; Dunnill, Charles W.; Parkin, Ivan P.

    2009-01-01

    Two series of composite thin films were deposited on glass by aerosol assisted chemical vapour deposition (AACVD)-nanoparticulate cerium dioxide and nanoparticulate cerium dioxide embedded in a titanium dioxide matrix. The films were analysed by a range of techniques including UV-visible absorption spectroscopy, X-ray diffraction, scanning electron microscopy and energy dispersive analysis by X-rays. The AACVD prepared films showed the functional properties of photocatalysis and super-hydrophilicity. The CeO 2 nanoparticle thin films displaying photocatalysis and photo-induced hydrophilicity almost comparable to that of anatase titania.

  11. Influence of carbon dioxide content in the biogas to nitrogen oxides emissions

    Directory of Open Access Journals (Sweden)

    Živković Marija A.

    2010-01-01

    Full Text Available Fuels derived from biomass are an alternative solution for the fossil fuel shortage. Usually this kind of fuels is called low calorific value fuels, due to the large proportion of inert components in their composition. The most common is carbon dioxide, and its proportion in biogas can be different, from 10 up to 40%, or even more. The presence of inert component in the composition of biogas causes the problems that are related with flame blow off limits. One of the possibilities for efficient combustion of biogas is the combustion in swirling flow including a pilot burner, aimed to expand the borders of stable combustion. This paper presents an analysis of the influence of the carbon dioxide content to the nitrogen oxides emissions. Laboratory biogas was used with different content of CO2 (10, 20, 30 and 40%. Investigation was carried out for different nominal powers, coefficients of excess air and carbon dioxide content. With increasing content of carbon dioxide, emission of nitrogen oxides was reduced, and this trend was the same throughout the whole range of excess air, carried out through measurements. Still, the influence of carbon dioxide content is significantly less than the influence of excess air. The coefficient of excess air greatly affects the production of radicals which are essential for the formation of nitrogen oxides, O, OH and CH. Also, the results show that the nominal power has no impact on the emission of nitrogen oxides.

  12. Biological fixation of carbon dioxide. Seibutsu ni yoru nisanka tanso no kotei

    Energy Technology Data Exchange (ETDEWEB)

    Someya, J [Fermentaion Research Institute, Tsukuba (Japan)

    1991-10-20

    Bulks of photosynthetic product to reduce the carbon dioxide by the light energy are forests, represented by the tropical rain forests, on the land, and marine algae and coral reefs in the ocean. For the purpose of effectively utilizing the fixation power of carbon dioxide through the photosynthesis by higher plants and algae, it is necessary to make many further researches, starting with a conditional selection of species, excellent in both absorption and fixation of carbon dioxide. The Japan Technology Transfer Association has recently issued a design to build a large scale closed type farm in the vicinity of factory, exhausting the carbon dioxide, and supply it to structure a system of producing vegetable and other food. What largely contributes to the calcification in the ocean is the coral reefs, where coral is symbiotic with brown algae., called dinoflagellatae. Those algae are judged to accelerate the formation of calcium carbonate by the photosynthesis. To estimate the absorption power of oceanic carbon dioxide, it is important to quantitatively know the calcification by the coral. 4 figs., 1 tab.

  13. Carbon Dioxide Capture from Flue Gas : Development and Evaluation of Existing and Novel Process Concepts

    NARCIS (Netherlands)

    Abu Zahra, M.R.M.

    2009-01-01

    One of the main global challenges in the years to come is to reduce the CO2 emissions in view of the apparent contribution to global warming. Carbon dioxide capture, transport, and storage (CCS) from fossil fuel fired power plants is drawing increased interest as an intermediate solution towards

  14. Reaction of yttrium polonides with carbon dioxide

    International Nuclear Information System (INIS)

    Abakumov, A.S.; Khokhlov, A.D.; Reznikova, N.F.

    1986-01-01

    It has been proved that heating of yttrium and tantalum in carbon dioxide to 500 and 800 0 C alters the gas phase composition, causing formation of carbon monoxide and reduction of oxygen content. A study of the thermal stability of yttrium polonides in carbon dioxide showed that yttrium sesqui- and monopolonides decompose at 400-430 0 C. The temperature dependence of the vapor pressure of polonium obtained upon decomposition of the referred polonides has been determined in a carbon dioxide environment radiotensometrically. The enthalpy of the process calculated from this dependence is close to the enthalpy of vaporization of elemental polonium in vacuo. The mechanism of the reactions has been suggested

  15. Carbon dioxide capture from power or process plant gases

    Science.gov (United States)

    Bearden, Mark D; Humble, Paul H

    2014-06-10

    The present invention are methods for removing preselected substances from a mixed flue gas stream characterized by cooling said mixed flue gas by direct contact with a quench liquid to condense at least one preselected substance and form a cooled flue gas without substantial ice formation on a heat exchanger. After cooling additional process methods utilizing a cryogenic approach and physical concentration and separation or pressurization and sorbent capture may be utilized to selectively remove these materials from the mixed flue gas resulting in a clean flue gas.

  16. 46 CFR 97.37-9 - Carbon dioxide alarm.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Carbon dioxide alarm. 97.37-9 Section 97.37-9 Shipping... Markings for Fire and Emergency Equipment, Etc. § 97.37-9 Carbon dioxide alarm. (a) All carbon dioxide alarms shall be conspicuously identified: “WHEN ALARM SOUNDS—VACATE AT ONCE. CARBON DIOXIDE BEING...

  17. 46 CFR 78.47-9 - Carbon dioxide alarm.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Carbon dioxide alarm. 78.47-9 Section 78.47-9 Shipping... and Emergency Equipment, Etc. § 78.47-9 Carbon dioxide alarm. (a) All carbon dioxide alarms shall be conspicuously identified: “WHEN ALARM SOUNDS—VACATE AT ONCE. CARBON DIOXIDE BEING RELEASED.” (b) [Reserved] ...

  18. 46 CFR 169.732 - Carbon dioxide alarm.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Carbon dioxide alarm. 169.732 Section 169.732 Shipping... Control, Miscellaneous Systems, and Equipment Markings § 169.732 Carbon dioxide alarm. Each carbon dioxide alarm must be conspicuously identified: “WHEN ALARM SOUNDS—VACATE AT ONCE. CARBON DIOXIDE BEING RELEASED.” ...

  19. 46 CFR 196.37-9 - Carbon dioxide alarm.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Carbon dioxide alarm. 196.37-9 Section 196.37-9 Shipping... Markings for Fire and Emergency Equipment, etc. § 196.37-9 Carbon dioxide alarm. (a) All carbon dioxide alarms shall be conspicuously identified: “WHEN ALARM SOUNDS—VACATE AT ONCE. CARBON DIOXIDE BEING...

  20. 46 CFR 108.627 - Carbon dioxide alarm.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Carbon dioxide alarm. 108.627 Section 108.627 Shipping... EQUIPMENT Equipment Markings and Instructions § 108.627 Carbon dioxide alarm. Each carbon dioxide alarm must be identified by marking: “WHEN ALARM SOUNDS VACATE AT ONCE. CARBON DIOXIDE BEING RELEASED” next to...

  1. Oligothiophene-S,S-dioxides as a class of electron-acceptor materials for organic photovoltaics

    International Nuclear Information System (INIS)

    Camaioni, N.; Ridolfi, G.; Fattori, V.; Favaretto, L.; Barbarella, G.

    2004-01-01

    Oligothiophene-S,S-dioxides are proposed as electron acceptors materials in organic blended photovoltaic devices. Photoinduced charge transfer is demonstrated in blends between a regioregular poly(3-hexylthiophene) and the oligomers, via photoluminescence spectroscopy. The enhanced photovoltaic performance exhibited by the blended cells, with respect to that of pristine devices in which the polymer is the active layer, represents further evidence for exciton dissociation. An increase of the power conversion efficiency up to sixty-fold is achieved by blending the polymer with the oligothiophene-S,S-dioxides

  2. Liquid carbon dioxide absorbents, methods of using the same, and related system

    Science.gov (United States)

    Perry, Robert James; Soloveichik, Grigorii Lev; Rubinsztajn, Malgorzata Iwona; O'Brien, Michael Joseph; Lewis, Larry Neil; Lam, Tunchiao Hubert; Kniajanski, Sergei; Hancu, Dan

    2018-05-01

    A carbon dioxide absorbent composition is described, including (i) a liquid, nonaqueous silicon-based material, functionalized with one or more groups that either reversibly react with CO2 or have a high-affinity for CO2, and (ii) a hydroxy-containing solvent that is capable of dissolving both the silicon-based material and a reaction product of the silicon-based material and CO2. The absorbent may be utilized in methods to reduce carbon dioxide in an exhaust gas, and finds particular utility in power plants.

  3. Liquid carbon dioxide absorbents, methods of using the same, and related systems

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Michael Joseph; Perry, Robert James; Lam, Tunchiao Hubert; Soloveichik, Grigorii Lev; Kniajanski, Sergei; Lewis, Larry Neil; Rubinsztajn, Malgorzata Iwona; Hancu, Dan

    2016-09-13

    A carbon dioxide absorbent composition is described, including (i) a liquid, nonaqueous silicon-based material, functionalized with one or more groups that either reversibly react with CO.sub.2 or have a high-affinity for CO.sub.2; and (ii) a hydroxy-containing solvent that is capable of dissolving both the silicon-based material and a reaction product of the silicon-based material and CO.sub.2. The absorbent may be utilized in methods to reduce carbon dioxide in an exhaust gas, and finds particular utility in power plants.

  4. Effect of sulfur dioxide partial pressure on the reaction of iodine, sulfur dioxide and water

    International Nuclear Information System (INIS)

    Nakajima, Hayato; Imai, Yoshiyuki; Kasahara, Seiji; Kubo, Shinji; Onuki, Kaoru

    2007-01-01

    Effect of sulfur dioxide partial pressure on the reaction of iodine, sulfur dioxide and water, which is a unit reaction in the IS process for thermochemical hydrogen production, was studied experimentally at 323 K under iodine saturation. Quasi-equilibrium state was observed in the presence of sulfur dioxide gas at constant pressure. The composition of the poly-hydriodic acid solution formed was discussed assuming an ideal desulfurization by the reverse reaction of the Bunsen reaction. The value of HI/(HI+H 2 O) of the desulfurized solution was large at high sulfur dioxide pressure and reached the maximum of 15.7 ± 0.3 mol%. (author)

  5. Carbon dioxide: making the right connection

    African Journals Online (AJOL)

    This highlights safety issues concerning pipeline provision of carbon dioxide, and that it is of utmost ... capnograph sample line, gas analysis unit, water trap and soda .... The heat generated by the chemical reaction between soda lime.

  6. Electrochemical reduction of sulfur dioxide in sulfolane

    Energy Technology Data Exchange (ETDEWEB)

    Vorob' ev, A.S.; Gavrilova, A.A.; Kolosnitsyn, V.S.; Nikitin, Yu.E.

    1985-09-01

    Solutions of sulfur dioxide in aproptic media are promising electrolyte oxidizing agents for chemical current sources with anodes of active metals. This work describes the electrochemical reduction of sulfur dioxide in sulfolane in a lithium halide supporting electrolyte which was investigated by the methods of voltamperometry and chronopotentiometry. The dependence of the current of the cathodic peak on the concentration of the supporting electrolyte salts, sulfur dioxide and water, was studied. On the basis of the data obtained, a hypothesis was advanced on the nature of the limiting step. The investigation showed that at low polarizing current densities, a substantial influence on the reduction of sulfur dioxide in sulfolane in a lithium halide supporting electrolyte is exerted by blockage of the electrode surface by sparingly soluble reaction products.

  7. integrated vertical photobioreactor system for carbon dioxide

    African Journals Online (AJOL)

    Astri Nugroho

    2013-07-02

    Jul 2, 2013 ... efficient system for converting carbon dioxide (CO2) into biomass. The use of ... often been thought to achieve the most efficient mixing and the best ... such process a photobioreactor is designed. Photobioreactor is a device ...

  8. More bad news about carbon dioxide emissions

    International Nuclear Information System (INIS)

    Stonehouse, D.

    2000-01-01

    The affect that increased carbon dioxide concentrations has on plants and animals was discussed. Most research focuses on the impacts that carbon dioxide concentrations has on climatic change. Recent studies, however, have shown that elevated levels of carbon dioxide in the atmosphere caused by burning fossils fuels changes the chemical structure of plants and could lead to significant disruptions in ecological food chains. High carbon dioxide levels cause plants to speed up photosynthesis, take in the gas, and use the carbon to produce more fibre and starch while giving off oxygen as a byproduct. As plants produce more carbon, their levels of nitrogen diminish making them less nutritious for the insects and animals that feed on them. This has serious implications for farmers, as pests would have to eat more of their crops to survive. In addition, farmers would have to supplement livestock with nutrients

  9. Technology of getting of microspheric thorium dioxide

    International Nuclear Information System (INIS)

    Balakhonov, V.G.; Matyukha, V.A.; Saltan, N.P.; Filippov, E.A.; Zhiganov, A.N.

    1999-01-01

    There has been proposed a technique for getting granulated thorium dioxide from its salts solutions according to the cryogenic technology by the method of a solid phase conversion. It includes the following operations: dispersion of the initial solution into liquid nitrogen and getting of cryogranules of the necessary size by putting oscillations of definite frequency on a die device and by charging formed drops in the constant electric field; solid phase conversion of thorium salts into its hydroxide by treating cryogranules with a cooled ammonia solution, drying and calcination of hydroxide granules having got granulated thorium dioxide. At the pilot facility there have been defined and developed optimum regimes for getting granulated thorium dioxide. The mechanism of thorium hydroxide cryogranules conversion into thorium dioxide was investigated by the thermal analysis methods. (author)

  10. Antipollution system to remove nitrogen dioxide gas

    Science.gov (United States)

    Metzler, A. J.; Slough, J. W.

    1971-01-01

    Gas phase reaction system using anhydrous ammonia removes nitrogen dioxide. System consists of ammonia injection and mixing section, reaction section /reactor/, and scrubber section. All sections are contained in system ducting.

  11. An Optimal Centralized Carbon Dioxide Repository for Florida, USA

    Directory of Open Access Journals (Sweden)

    Brandon Poiencot

    2011-03-01

    Full Text Available For over a decade, the United States Department of Energy, and engineers, geologists, and scientists from all over the world have investigated the potential for reducing atmospheric carbon emissions through carbon sequestration. Numerous reports exist analyzing the potential for sequestering carbon dioxide at various sites around the globe, but none have identified the potential for a statewide system in Florida, USA. In 2005, 83% of Florida’s electrical energy was produced by natural gas, coal, or oil (e.g., fossil fuels, from power plants spread across the state. In addition, only limited research has been completed on evaluating optimal pipeline transportation networks to centralized carbon dioxide repositories. This paper describes the feasibility and preliminary locations for an optimal centralized Florida-wide carbon sequestration repository. Linear programming optimization modeling is used to plan and route an idealized pipeline network to existing Florida power plants. Further analysis of the subsurface geology in these general locations will provide insight into the suitability of the subsurface conditions and the available capacity for carbon sequestration at selected possible repository sites. The identification of the most favorable site(s is also presented.

  12. Thorium dioxide: properties and nuclear applications

    International Nuclear Information System (INIS)

    Belle, J.; Berman, R.M.

    1984-01-01

    This is the sixth book on reactor materials published under sponsorship of the Naval Reactors Office of the United States Department of Energy, formerly the United States Atomic Energy Commission. This book presents a comprehensive compilation of the most significant properties of thorium dioxide, much like the book Uranium Dioxide: Properties and Nuclear Applications presented information on the fuel material used in the Shippingport Pressurized Water Reactor core

  13. Thorium dioxide: properties and nuclear applications

    Energy Technology Data Exchange (ETDEWEB)

    Belle, J.; Berman, R.M. (eds.)

    1984-01-01

    This is the sixth book on reactor materials published under sponsorship of the Naval Reactors Office of the United States Department of Energy, formerly the United States Atomic Energy Commission. This book presents a comprehensive compilation of the most significant properties of thorium dioxide, much like the book Uranium Dioxide: Properties and Nuclear Applications presented information on the fuel material used in the Shippingport Pressurized Water Reactor core.

  14. World warms to nuclear power

    International Nuclear Information System (INIS)

    Mortimer, N.

    1989-01-01

    The greenhouse effect and global warming is a major environmental issue. The nuclear industry has taken this opportunity to promote itself as providing clean energy without implication in either the greenhouse effect or acid rain. However, it is acknowledged that nuclear power does have its own environment concerns. Two questions are posed -does nuclear power contribute to carbon dioxide emissions and can nuclear power provide a realistic long-term solution to global warming? Although nuclear power stations do not emit carbon dioxide, emissions occur during the manufacture of reactor components, the operation of the nuclear fuel cycle and especially, during the mining and processing of the uranium ore. It is estimated that the supply of high grade ores will last only 23 years, beyond that the carbon dioxide emitted during the processing is estimated to be as great as the carbon dioxide emitted from an coal-fired reactor. Fast breeder reactors are dismissed as unable to provide an answer, so it is concluded that nuclear technology has only a very limited role to play in countering global warming.(UK)

  15. Supercritical carbon dioxide hop extraction

    Directory of Open Access Journals (Sweden)

    Pfaf-Šovljanski Ivana I.

    2005-01-01

    Full Text Available The hop of Magnum cultivar was extracted using supercritical carbon dioxide (SFE-as extractant. Extraction was carried out in the two steps: the first one being carried out at 150 bar and 40°C for 2.5 h (Extract A, and the second was the extraction of the same hop sample at 300 bar and 40°C for 2.5 h (Extract B. Extraction kinetics of the system hop-SFE-CO2 was investigated. Two of four most common compounds of hop aroma (α-humulene and β-caryophyllene were detected in Extract A. Isomerised α-acids and β-acids were detected too. a-Acid content in Extract B was high (that means it is a bitter variety of hop. Mathematical modeling using empirical model characteristic time model and simple single sphere model has been performed on Magnum cultivar extraction experimental results. Characteristic time model equations, best fitted experimental results. Empirical model equation, fitted results well, while simple single sphere model equation poorly approximated the results.

  16. Report of the Carbon Dioxide Committee II

    International Nuclear Information System (INIS)

    1994-01-01

    The Carbon Dioxide Committee was given the task of preparing a suggestion of the acts aimed at reducing the greenhouse gas emissions and increasing the sinks of carbon in Finland. Emissions of all greenhouse gases were in 1990 80 million tons. calculated as carbon dioxide. The carbon dioxide emissions were about 58 million tons of the total. The increase of forest resources binds carbon from the atmosphere and reduces thereby net emissions of Finland at present by nearly 30 million tons of carbon dioxide. Carbon dioxide emissions will grow during the next decades, unless strong measures to control them will not be taken. As a result of the Commissions examination, acts will be needed both in the production of energy and in its consumption. Emissions can be reduced by replacing fossil fuels with nuclear energy, bioenergy and other renewable energy sources. Saving of energy and improvement of energy efficiency will limit carbon dioxide emissions. The Commission has made suggestions both to change the structure of energy production and to control the consumption of energy. (orig.)

  17. Sulfur dioxide concentration measurements in the vicinity of the Albert Funk mining and metallurgical plant complex

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, M

    1976-01-01

    This article discusses the ambient air concentration of sulfur dioxide in the area of Freiberg, GDR. The emission of sulfur dioxide results for the most part from brown coal combustion in heat and power plants and in metallurgical plants. Sulfur dioxide emission from neighboring industrial centers such as Dresden and North Bohemian towns affects the Freiburg area to some extent. The use of brown coal in household heating contributes an average of 50 kg of sulfur dioxide emission per coal burning household annually. A total of 1260 measurements at 28 points in the vicinity of Freiberg were made in the year 1972 in evaluating the concentration of sulfur dioxide present in the air. In 75% of the measurements the concentrations were below 0.15 mg/mat3, in 12% between 0.15 and 0.2 mg/mat3, in 7% between 0.2 and 0.3 mg/mat3 and in 6% between 0.3 and 0.5 mg/mat3. The results are described as average industrial pollution. The influence of air temperature, wind velocity, fog, season and time of day are also discussed. (4 refs.) (In German)

  18. Understanding the carbon dioxide gaps.

    Science.gov (United States)

    Scheeren, Thomas W L; Wicke, Jannis N; Teboul, Jean-Louis

    2018-06-01

    The current review attempts to demonstrate the value of several forms of carbon dioxide (CO2) gaps in resuscitation of the critically ill patient as monitor for the adequacy of the circulation, as target for fluid resuscitation and also as predictor for outcome. Fluid resuscitation is one of the key treatments in many intensive care patients. It remains a challenge in daily practice as both a shortage and an overload in intravascular volume are potentially harmful. Many different approaches have been developed for use as target of fluid resuscitation. CO2 gaps can be used as surrogate for the adequacy of cardiac output (CO) and as marker for tissue perfusion and are therefore a potential target for resuscitation. CO2 gaps are easily measured via point-of-care analysers. We shed light on its potential use as nowadays it is not widely used in clinical practice despite its potential. Many studies were conducted on partial CO2 pressure differences or CO2 content (cCO2) differences either alone, or in combination with other markers for outcome or resuscitation adequacy. Furthermore, some studies deal with CO2 gap to O2 gap ratios as target for goal-directed fluid therapy or as marker for outcome. CO2 gap is a sensitive marker of tissue hypoperfusion, with added value over traditional markers of tissue hypoxia in situations in which an oxygen diffusion barrier exists such as in tissue oedema and impaired microcirculation. Venous-to-arterial cCO2 or partial pressure gaps can be used to evaluate whether attempts to increase CO should be made. Considering the potential of the several forms of CO2 measurements and its ease of use via point-of-care analysers, it is recommendable to implement CO2 gaps in standard clinical practice.

  19. Graphite suspension in carbon dioxide

    International Nuclear Information System (INIS)

    Roche, R.

    1965-01-01

    Since 1963 the Atomic Division of SNECMA has been conducting, under a contract with the CEA, an experimental work with a two-component fluid comprised of carbon dioxide and small graphite particles. The primary purpose was the determination of basic engineering information pertaining to the stability and the flowability of the suspension. The final form of the experimental loop consists mainly of the following items: a light-phase compressor, a heavy-phase pump, an electrical-resistance type heater section, a cooling heat exchanger, a hairpin loop, a transparent test section and a separator. During the course of the testing, it was observed that the fluid could be circulated quite easily in a broad range of variation of the suspension density and velocity - density from 30 to 170 kg/m 3 and velocity from 2 to 24 m/s. The system could be restarted and circulation maintained without any difficulty, even with the heavy-phase pump alone. The graphite did not have a tendency to pack or agglomerate during operation. No graphite deposition was observed on the wall of the tubing. A long period run (250 hours) has shown the evolution of the particle dimensions. Starting with graphite of surface area around 20 m 2 /g (graphite particles about 1 μ), the powder surface area reaches an asymptotic value of 300 m 2 /g (all the particles less than 0.3 μ). Moisture effect on flow stability, flow distribution between two parallel channels, pressure drop in straight tubes, recompression ratio in diffusers were also investigated. (author) [fr

  20. Chemoselective alternating copolymerization of limonene dioxide and carbon dioxide : a new highly functional aliphatic epoxy polycarbonate

    NARCIS (Netherlands)

    Li, C.; Sablong, R.J.; Koning, C.E.

    The alternating copolymerization of biorenewable limonene dioxide with carbon dioxide (CO2) catalyzed by a zinc β-diiminate complex is reported. The chemoselective reaction results in linear amorphous polycarbonates that carry pendent methyloxiranes and exhibit glass transition temperatures (Tg) up

  1. Process for the preparation of uranium dioxide

    International Nuclear Information System (INIS)

    Watt, G.W.; Baugh, D.W. Jr.

    1977-01-01

    An actinide dioxide, e.g., uranium dioxide, plutonium dioxide, neptunium dioxide, etc., is prepared by reacting the actinide nitrate hexahydrate with sodium dithionite as a first step; the reaction product from this first step is a novel composition of matter comprising the actinide sulfite tetrahydrate. The reaction product resulting from this first step is then converted to the actinide dioxide by heating it in the absence of an oxygen-containing atmosphere (e.g., nitrogen) to a temperature of about 500 0 to about 950 0 C for about 15 to about 135 minutes. If the reaction product resulting from the first step is, prior to carrying out the second heating step, exposed to an oxygen-containing atmosphere such as air, the resultant product is a novel composition of matter comprising the actinide oxysulfite tetrahydrate which can also be readily converted to the actinide dioxide by heating it in the absence of an oxygen-containing atmosphere (e.g., nitrogen) at a temperature of about 400 0 to about 900 0 C for about 30 to about 150 minutes. Further, the actinide oxysulfite tetrahydrate can be partially dehydrated at reduced pressures (and in the presence of a suitable dehydrating agent such as phosphorus pentoxide). The partially dehydrated product may be readily converted to the dioxide form by heating it in the absence of an oxygen-containing atmosphere (e.g., nitrogen) at a temperature of about 500 0 to about 900 0 C for about 30 to about 150 minutes. 16 claims

  2. France without nuclear power

    International Nuclear Information System (INIS)

    Charmant, A.; Devezeaux, J.G.; Ladoux, N.; Vielle, M.

    1991-01-01

    As coal production declined and France found herself in a condition of energy dependency, the country decided to turn to nuclear power and a major construction program was undertaken in 1970. The consequences of this step are examined in this article, by imagining where France would be without its nuclear power. At the end of the sixties, fuel-oil incontestably offered the cheapest way of producing electricity; but the first petroleum crisis was to upset the order of economic performance, and coal then became the more attractive fuel. The first part of this article therefore presents coal as an alternative to nuclear power, describing the coal scenario first and then comparing the relative costs of nuclear and coal investment strategies and operating costs (the item that differs most is the price of the fuel). The second part of the article analyzes the consequences this would have on the electrical power market, from the supply and demand point of view, and in terms of prices. The third part of the article discusses the macro-economic consequences of such a step: the drop in the level of energy dependency, increased costs and the disappearance of electricity exports. The article ends with an analysis of the environmental consequences, which are of greater and greater concern today. The advantage here falls very much in favor of nuclear power, if we judge by the lesser emissions of sulfur dioxide, nitrogen oxides and especially carbon dioxide. 22 refs.; 13 figs.; 10 tabs

  3. Sol-gel growth of vanadium dioxide

    International Nuclear Information System (INIS)

    Speck, K.R.

    1990-01-01

    This thesis examines the chemical reactivity of vanadium (IV) tetrakis(t-butoxide) as a precursor for the sol-gel synthesis of vanadium dioxide. Hydrolysis and condensation of the alkoxide was studied by FTIR spectroscopy. Chemical modification of the vanadium tetraalkoxide by alcohol interchange was studied using 51 V NMR and FTIR. Vanadium dioxide thin films and powders were made from vanadium tetrakis(t-butoxide) by standard sol-gel techniques. Post-deposition heating under nitrogen was necessary to transform amorphous gels into vanadium dioxide. Crystallization of films and powders was studied by FTIR, DSC, TGA, and XRD. Gel-derived vanadium dioxide films undergo a reversible semiconductor-to-metal phase transition near 68C, exhibiting characteristic resistive and spectral changes. The electrical resistance decreased by two to three orders of magnitude and the infrared transmission sharply dropped as the material was cycled through this thermally induced phase transition. The sol-gel method was also used to make doped vanadium dioxide films. Films were doped with tungsten and molybdenum ions to effectively lower the temperature at which the transition occurs

  4. Effects of sulfur dioxide on vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Whitby, G S

    1939-11-11

    A discussion is presented on the effects of sulfur dioxide on vegetation as observed at Trail, British Columbia. The investigation was carried out over a period of eight years, 1929 to 1937. The concentration of sulfur dioxide at the United States border was carefully determined throughout the crop season at a point 16 miles from the source of sulfur dioxide. Maximum and average concentrations in part per million are given. The sulfur content of vegetation was determined and was found to diminish as the distance from the smelter increased. It was determined that the sulfur content may rise to four times the normal amount without injurious effect. This is particularly so with prolonged low concentration. The effect on the soil was determined by measuring soluble sulfate, pH and exchangeable bases. The soil near the plant was affected, but this fell off rapidly with increase in distance so that eight miles from the smelter the soil was substantially normal. No effect on water supplies was found. An appreciable retardation in growth, as determined by annular rings, was noted for trees exposed to the sulfur dioxide. This effect was lost following installation of sulfur dioxide control at Trail. Conifers were found more susceptible during periods of active growth than when dormant. Also, transplanted conifers were more severly affected than native trees. Seedlings were less resistant that older trees.

  5. Study of Soil Decontamination Method Using Supercritical Carbon Dioxide and TBP

    International Nuclear Information System (INIS)

    Park, Jihye; Park, Kwangheon; Jung, Wonyoung

    2014-01-01

    The result of this study means that we have a possible new method for cheap and less wasteful nuclear waste decontamination. When severe accidents such as the incident at the Fukushima nuclear site occur, the soil near the power plant is contaminated with fission products or the activation metal structure of the power plant. The soil pollution form depends on the environment and soil characteristics of the contaminated areas. Thus, a- single-decontamination method is not effective for site cleanup. In addition, some soil decontamination methods are expensive and large amounts of secondary waste are generated. Therefore, we need new soil decontamination methods. In this study, instead of using a conventional solvent method that generates secondary waste, supercritical carbon dioxide was used to remove metal ions from the soil. Supercritical carbon dioxide is known for good permeation characteristics. We expect that we will reduce the cost of soil pollution management. Supercritical carbon dioxide can decontaminate soil easily, as it has the ability to penetrate even narrow gaps with very good moisture permeability. We used TBP, which is a known for extractant of actinium metal. TBP is usually used for uranium and strontium extraction. Using TBP-HNO 3 complex and supercritical carbon dioxide, we did extraction experiments for several heavy metals in contaminated soil

  6. Study of Soil Decontamination Method Using Supercritical Carbon Dioxide and TBP

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jihye; Park, Kwangheon; Jung, Wonyoung [Kyunghee Univ., Yongin (Korea, Republic of)

    2014-05-15

    The result of this study means that we have a possible new method for cheap and less wasteful nuclear waste decontamination. When severe accidents such as the incident at the Fukushima nuclear site occur, the soil near the power plant is contaminated with fission products or the activation metal structure of the power plant. The soil pollution form depends on the environment and soil characteristics of the contaminated areas. Thus, a- single-decontamination method is not effective for site cleanup. In addition, some soil decontamination methods are expensive and large amounts of secondary waste are generated. Therefore, we need new soil decontamination methods. In this study, instead of using a conventional solvent method that generates secondary waste, supercritical carbon dioxide was used to remove metal ions from the soil. Supercritical carbon dioxide is known for good permeation characteristics. We expect that we will reduce the cost of soil pollution management. Supercritical carbon dioxide can decontaminate soil easily, as it has the ability to penetrate even narrow gaps with very good moisture permeability. We used TBP, which is a known for extractant of actinium metal. TBP is usually used for uranium and strontium extraction. Using TBP-HNO{sub 3} complex and supercritical carbon dioxide, we did extraction experiments for several heavy metals in contaminated soil.

  7. Lagrangian measurements of sulfur dioxide to sulfate conversion rates

    Energy Technology Data Exchange (ETDEWEB)

    Zak, B D

    1981-12-01

    On the basis of Project MISTT data and proposed homogenous gas phase oxidation mechanisms for sulfur dioxide, it has been suggested that the degree of mixing with background air, the chemical composition of the background air, and the intensity of the sunlight available are key factors determining the rate of sulfur dioxide to sulfate conversion. These hypotheses are examined in light of Lagrangian measrements of conversion rates in power plant plumes made during the Tennessee Plume Study and Project Da Vinci. It is found that the Lagrangian conversion rate measurements are consistent with these hypotheses. It has also been suggested that the concentration of ozone may serve as a workable surrogate for the concentrations of the free radicals involved in the homogeneous gas phase mechanism. The night-time Lagrangian data remind one that the gross difference in mean lifetime of ozone and free radicals can lead to situations in which the ozone concentration is not a good surrogate for the free radical concentrations.

  8. Reaction of titanium polonides with carbon dioxide

    International Nuclear Information System (INIS)

    Abakumov, A.S.; Malyshev, M.L.; Reznikova, N.F.

    1987-01-01

    It has been ascertained that heating titanium and tantalum in carbon dioxide to temperatures of 500 or 800 0 C alters the composition of the gas phase, causing the advent of carbon monoxide and lowering the oxygen content. Investigation of the thermal stability of titanium polonides in a carbon dioxide medium has shown that titanium mono- and hemipolonides are decomposed at temperatures below 350 0 C. The temperature dependence of the vapor pressure of polonium produced in the decomposition of these polonides in a carbon dioxide medium have been determined by a radiotensimetric method. The enthalpy of the process, calculated from this relationship, is close to the enthalpy of vaporization of elementary polonium in vacuo

  9. Measurement of nitrogen dioxide in the air

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, J T

    1967-01-01

    The Hersch electrolytic nitrogen dioxide generator has been used to provide accurately known weights of nitrogen dioxide and hence to evaluate a calibration factor for the colorimetric reagent described by Saltaman for the determination of this gas. A method of testing whether the electrolytic generator was giving a quantitative output of NO/sub 2/ is described. The work has confirmed Saltman's value of 0.72 for the calibration factor. An assertion that the calibration factor is dependent on the concentration of nitrogen dioxide sampled, is re-examined and dismissed, the observations being re-interpreted on a simple basis. A tentative suggestion is made as to why, in recent work by Stratmann and Buck, a calibration factor equal to unity has been found. 8 references, 4 figures, 1 table.

  10. Carbon dioxide problem: solution by technical countermeasures

    Energy Technology Data Exchange (ETDEWEB)

    Bach, W

    1978-02-15

    A rough assessment indicates that anthropogenic influences might raise the mean global surface temperature by 0.8 to 1.2 C in 2000 AD and by 2 to 4 C in 2050 AD. The rapidly increasing levels of atmospheric carbon dioxide are largely responsible for this warming trend. A variety of measures for the reduction of carbon dioxide emissions is presented. One promising approach is to work out a world-wide energy mix that can counteract a temperature increase. (In German)

  11. Environmental effects of increased atmospheric carbon dioxide

    International Nuclear Information System (INIS)

    Soon, W.; Baliunas, S.L.; Robinson, A.B.; Robinson, Z.W.

    1999-01-01

    A review of the literature concerning the environmental consequences of increased levels of atmospheric carbon dioxide leads to the conclusion that increases during the 20th century have produced no deleterious effects upon global climate or temperature. Increased carbon dioxide has, however, markedly increased plant growth rates as inferred from numerous laboratory and field experiments. There is no clear evidence, nor unique attribution, of the global effects of anthropogenic CO 2 on climate. Meaningful integrated assessments of the environmental impacts of anthropogenic CO 2 are not yet possible because model estimates of global and regional climate changes on interannual, decadal and centennial timescales remain highly uncertain.(author)

  12. Determination of sulfur dioxide by a radiorelease method

    Energy Technology Data Exchange (ETDEWEB)

    Sriman Narayanan, S.; Rao, V.R.S. (Indian Inst. of Tech., Madras. Dept. of Chemistry)

    1983-04-13

    A radiorelease technique for the determination of sulfur dioxide using radiochlor /sup 36/Cl-amine-T is described. Methods for the elimination of interference from coexisting gases are also reported. 1-40 ppm sulfur dioxide can be determined.

  13. Determination of sulfur dioxide by a radiorelease method

    International Nuclear Information System (INIS)

    Sriman Narayanan, S.; Rao, V.R.S.

    1983-01-01

    A radiorelease technique for the determination of sulfur dioxide using radiochlor 36 Cl-amine-T is described. Methods for the elimination of interference from coexisting gases are also reported. 1-40 ppm sulfur dioxide can be determined. (author)

  14. Catalyst retention in continuous flow with supercritical carbon dioxide

    NARCIS (Netherlands)

    Stouten, S.C.; Noel, T.; Wang, Q.; Hessel, V.

    2014-01-01

    This review discusses the retention of organometallic catalysts in continuous flow processes utilizing supercritical carbon dioxide. Due to its innovative properties, supercritical carbon dioxide offers interesting possibilities for process intensification. As a result of safety and cost

  15. 40 CFR 52.728 - Control strategy: Nitrogen dioxide. [Reserved

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. [Reserved] 52.728 Section 52.728 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR...: Nitrogen dioxide. [Reserved] ...

  16. Effect of sulfur dioxide on proteins of the vegetable organism

    Energy Technology Data Exchange (ETDEWEB)

    Reckendorfer, P; Beran, F

    1931-01-01

    Experiments were performed to determine the effects of sulfur dioxide on red clover in a controlled environment. An increase in the concentration of sulfur dioxide caused a significant decrease in the digestible protein. However, after the sulfur dioxide was discontinued, there was a decrease in the indigestible protein. The leaves showed an increase in spotting with an increase in sulfur dioxide concentration. Chemical analysis of the soil revealed a higher sulfur content in these experiments.

  17. Predictor of regulation of uranium dioxide powder pressing process

    International Nuclear Information System (INIS)

    Motta, Eduardo Souza; Araujo, Victor Hugo Leal de; Bernardelli, Sergio Henrique

    2007-01-01

    One of the most important steps of the uranium dioxide pellets fabrication used in the nuclear fuel elements is the green pellets pressing. The target density of the pellets after the sintering process determines the density of the green pellet. To meet the same sintered target density the green density may vary according to the powder characteristics. These variations implies in changing the regulation of the press for different powder's patches. The regulation done empirically imply in productivity loss and necessity of reprocessing the pellets pressed during the press regulation and also depends on the operator experience. At this work, was developed an artificial neural network feed forward back propagation to predict the press regulation, depending on the powder characteristics and the green pellet's target density. The results obtained at INB - Industrias Nucleares do Brasil S. A. during the fabrication of the fifth recharge of Angra II nuclear power plant are presented. (author)

  18. Modelling of tetrahydrofuran promoted gas hydrate systems for carbon dioxide capture processes

    DEFF Research Database (Denmark)

    Herslund, Peter Jørgensen; Thomsen, Kaj; Abildskov, Jens

    2014-01-01

    A thermodynamic study of a novel gas hydrate based CO2 capture process is presented.•Model predicts this process unsuitable for CO2 capture from power station flue gases. A thermodynamic modelling study of both fluid phase behaviour and hydrate phase behaviour is presented for the quaternary system...... of water, tetrahydrofuran, carbon dioxide and nitrogen. The applied model incorporates the Cubic-Plus-Association (CPA) equation of state for the fluid phase description and the van der Waals-Platteeuw hydrate model for the solid (hydrate) phase. Six binary pairs are studied for their fluid phase behaviour...... accurate descriptions of both fluid- and hydrate phase equilibria in the studied system and its subsystems. The developed model is applied to simulate two simplified, gas hydrate-based processes for post-combustion carbon dioxide capture from power station flue gases. The first process, an unpromoted...

  19. Array of titanium dioxide nanostructures for solar energy utilization

    Science.gov (United States)

    Qiu, Xiaofeng; Parans Paranthaman, Mariappan; Chi, Miaofang; Ivanov, Ilia N; Zhang, Zhenyu

    2014-12-30

    An array of titanium dioxide nanostructures for solar energy utilization includes a plurality of nanotubes, each nanotube including an outer layer coaxial with an inner layer, where the inner layer comprises p-type titanium dioxide and the outer layer comprises n-type titanium dioxide. An interface between the inner layer and the outer layer defines a p-n junction.

  20. Metabolic effects of Carbon Dioxide (CO 2 ) insufflation during ...

    African Journals Online (AJOL)

    Metabolic effects of Carbon Dioxide (CO 2 ) insufflation during laparoscopic surgery: changes in pH, arterial partial Pressure of Carbon Dioxide (PaCo 2 ) and End Tidal Carbon Dioxide (EtCO 2 ) ... Respiratory adjustments were done for EtCO2 levels above 60mmHg or SPO2 below 92% or adverse haemodynamic changes.

  1. 27 CFR 24.319 - Carbon dioxide record.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Carbon dioxide record. 24..., DEPARTMENT OF THE TREASURY LIQUORS WINE Records and Reports § 24.319 Carbon dioxide record. A proprietor who uses carbon dioxide in still wine shall maintain a record of the laboratory tests conducted to...

  2. 40 CFR 180.444 - Sulfur dioxide; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... § 180.444 Sulfur dioxide; tolerances for residues. A tolerance is established as follows for sulfite residues of the fungicide sulfur dioxide (determined as (SO2)) in or on the following raw agricultural... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Sulfur dioxide; tolerances for...

  3. 27 CFR 26.222 - Still wines containing carbon dioxide.

    Science.gov (United States)

    2010-04-01

    ... carbon dioxide. 26.222 Section 26.222 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND... ISLANDS Formulas for Products From the Virgin Islands § 26.222 Still wines containing carbon dioxide. (a) General. Still wines may contain not more than 0.392 gram of carbon dioxide per 100 milliliters of wine...

  4. 27 CFR 26.52 - Still wines containing carbon dioxide.

    Science.gov (United States)

    2010-04-01

    ... carbon dioxide. 26.52 Section 26.52 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND... ISLANDS Formulas for Products From Puerto Rico § 26.52 Still wines containing carbon dioxide. (a) General. Still wines may contain not more than 0.392 gram of carbon dioxide per 100 milliliters of wine; except...

  5. 21 CFR 172.480 - Silicon dioxide.

    Science.gov (United States)

    2010-04-01

    ... alcohol in tableted foods for special dietary use, in an amount not greater than that required to... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Silicon dioxide. 172.480 Section 172.480 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN...

  6. Yellow cake to ceramic uranium dioxide

    International Nuclear Information System (INIS)

    Zawidzki, T.W.; Itzkovitch, I.J.

    1983-01-01

    This overview article first reviews the processes for converting uranium ore concentrates to ceramic uranium dioxide at the Port Hope Refinery of Eldorado Resources Limited. In addition, some of the problems, solutions, thoughts and research direction with respect to the production and properties of ceramic UO 2 are described

  7. Carbon dioxide capture and air quality

    NARCIS (Netherlands)

    Horssen, A. van; Ramirez, C.A.; Harmelen, T. van; Koornneef, J.

    2011-01-01

    Carbon dioxide (CO2) is one of the most important greenhouse gases (GHG). The most dominant source of anthropogenic CO2 contributing to the rise in atmospheric concentration since the industrial revolution is the combustion of fossil fuels. These emissions are expected to result in global climate

  8. Electrocatalytic carbon dioxide reduction - a mechanistic study

    NARCIS (Netherlands)

    Schouten, Klaas Jan Schouten

    2013-01-01

    This thesis presents new insights into the reduction of carbon dioxide to methane and ethylene on copper electrodes. This electrochemical process has great potential for the storage of surplus renewable electrical energy in the form of hydrocarbons. The research described in this thesis focuses on

  9. Carbon dioxide enhances fragility of ice crystals

    International Nuclear Information System (INIS)

    Qin Zhao; Buehler, Markus J

    2012-01-01

    Ice caps and glaciers cover 7% of the Earth, greater than the land area of Europe and North America combined, and play an important role in global climate. The small-scale failure mechanisms of ice fracture, however, remain largely elusive. In particular, little understanding exists about how the presence and concentration of carbon dioxide molecules, a significant component in the atmosphere, affects the propensity of ice to fracture. Here we use atomic simulations with the first-principles based ReaxFF force field capable of describing the details of chemical reactions at the tip of a crack, applied to investigate the effects of the presence of carbon dioxide molecules on ice fracture. Our result shows that increasing concentrations of carbon dioxide molecules significantly decrease the fracture toughness of the ice crystal, making it more fragile. Using enhanced molecular sampling with metadynamics we reconstruct the free energy landscape in varied chemical microenvironments and find that carbon dioxide molecules affect the bonds between water molecules at the crack tip and decrease their strength by altering the dissociation energy of hydrogen bonds. In the context of glacier dynamics our findings may provide a novel viewpoint that could aid in understanding the breakdown and melting of glaciers, suggesting that the chemical composition of the atmosphere can be critical to mediate the large-scale motion of large volumes of ice.

  10. Diiodination of Alkynes in supercritical Carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    李金恒; 谢叶香; 尹笃林; 江焕峰

    2003-01-01

    A general,green and efficient method for the synthesis of transdiiodoalkenes in CO2(sc) has been developed.Trans-diiodoalkenes were obtained stereospecifically in quantitative yields via diiodination of both electron-rich and electron-deficient alkynes in the presence of KI,Ce(SO4)2 and water in supercritical carbon dioxide [CO2(sc)]at 40℃.

  11. Tourism Transport, Technology, and Carbon Dioxide Emissions

    NARCIS (Netherlands)

    Peeters, P.M.

    2010-01-01

    Technological development from horse-drawn carriages to the new Airbus A380 has led to a remarkable increase in both the capacity and speed of tourist travel. This development has an endogenous systemic cause and will continue to increase carbon dioxide emissions/energy consumption if left

  12. Improved ionic model of liquid uranium dioxide

    NARCIS (Netherlands)

    Gryaznov, [No Value; Iosilevski, [No Value; Yakub, E; Fortov, [No Value; Hyland, GJ; Ronchi, C

    The paper presents a model for liquid uranium dioxide, obtained by improving a simplified ionic model, previously adopted to describe the equation of state of this substance [1]. A "chemical picture" is used for liquid UO2 of stoichiometric and non-stoichiometric composition. Several ionic species

  13. Carbon dioxide sensing with sulfonated polyaniline

    NARCIS (Netherlands)

    Doan, D.C.T.; Ramaneti, R.; Baggerman, J.; Bent, van der J.; Marcelis, A.T.M.; Tong, H.D.; Rijn, van C.J.M.

    2012-01-01

    The use of polyaniline and especially sulfonated polyaniline (SPAN) is explored for sensing carbon dioxide (CO2) at room temperature. Frequency-dependent AC measurements were carried out to detect changes in impedance of the polymer, drop casted on interdigitated electrodes, when exposed to CO2 gas.

  14. Transport properties of supercritical carbon dioxide

    NARCIS (Netherlands)

    Lavanchy, F.; Fourcade, E.; de Koeijer, E.A.; Wijers, J.G.; Meyer, T.; Keurentjes, J.T.F.; Kemmere, M.F.; Meyer, T.

    2005-01-01

    Recently, supercritical fluids have emerged as more sustainable alternatives for the organic solvents often used in polymer processes. This is the first book emphasizing the potential of supercritical carbon dioxide for polymer processes from an engineering point of view. It develops a

  15. Can carbon dioxide storage help cut greenhouse emissions? A simplified guide to the IPCC's 'Special Report on Carbon Dioxide Capture and Storage'

    International Nuclear Information System (INIS)

    2006-06-01

    Fossil fuels account for 75 - 80% of today's global energy use and three quarters of humanity's total carbon dioxide emissions. Without specific actions to minimize our impact on the climate, carbon dioxide (CO2) emissions from fossil-fuel energy are projected to swell over the course of the 21st century. The consequences - a global temperature rise of 1.4 - 5.8C and shifting patterns of weather and extreme events - could prove disastrous for future generations. Stabilizing or reducing global emissions of carbon dioxide and other greenhouse gases over the coming decades will challenge human ingenuity. Fortunately, the IPCC's Third Assessment Report, published in 2001, concluded that existing and emerging technologies for limiting emissions could - if supported by the right policies - stabilize atmospheric concentrations of greenhouse gases by the end of the century at levels that would limit further climate change. No single technology will suffice by itself; instead, a combination of technologies will be required. Many of the most promising technologies will contribute by improving the energy efficiency of certain processes and products or by converting solar, wind and other noncarbon power sources into usable energy. But with oil, coal and gas set to remain the primary sources of energy for decades to come, governments and industry are also examining technologies for reducing emissions from these fuels. One such technology is known as carbon dioxide capture and storage. Abbreviated as CCS, this technology could be used by large c1 Introduction stationary 'point sources' such as fossil fuel-fired power plants and industrial facilities to prevent their CO2 emissions from entering the atmosphere and contributing to climate change. To learn more about this technology's potential, the member governments of the United Nations Framework Convention on Climate Change asked the IPCC to assess the current state of knowledge about carbon dioxide storage and capture. The IPCC

  16. Manufacturing sector carbon dioxide emissions in nine OECD countries 1973--87: A Divisia index decomposition to changes in fuel mix, emission coefficients, industry structure, energy intensities, and international structure

    International Nuclear Information System (INIS)

    Torvanger, A.

    1990-11-01

    In this paper the reduction in energy-related manufacturing carbon dioxide emissions for nine OECD countries in the period 1973 to 1987 is analyzed. Carbon dioxide emissions are estimated from energy use data. The emphasis is on carbon dioxide intensities, defined as emissions divided by value added. The overall manufacturing carbon dioxide intensity for the nine OECD countries was reduced by 42% in the period 1973--1987. Five fuels are specified together with six subsectors of manufacturing. Carbon dioxide emissions are estimated from fossil fuel consumption, employing emissions coefficients for gas, oil and solids. In addition, electricity consumption is specified. For electricity use an emission coefficient index is calculated from the shares of fossil fuels, nuclear power and hydro power used to generate electricity, and the efficiency in electricity generation from these energy sources. A Divisia index approach is used to sort out the contribution to reduced carbon dioxide intensity from different components. The major finding is that the main contribution to reduced carbon dioxide intensity is from the general reduction in manufacturing energy intensity, most likely driven by economic growth and increased energy prices, giving incentives to invest in new technology and new industrial processes. There is also a significant contribution from reduced production in the most carbon dioxide intensive subsectors, and a contribution from higher efficiency in electricity generation together with a larger nuclear power share at the expense of oil. 19 refs., 5 figs., 11 tabs

  17. Dependence of carbon dioxide concentration on microalgal carbon dioxide fixation

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Yeoung Sang; Park, Song Moon [Department of Chemical Engineering, School of Environmental Engineering, Pohang University of Science and Technology, Pohang (Korea); Bolesky, Bohumil [Department of Chemical Engineering, McGill University (Canada)

    1999-10-01

    Batch cultivation of chlorella vulgaris was carried out under various CO{sub 2} concentrations in order to understand and describe mathematically the CO{sub 2} inhibition of microalgal CO{sub 2} fixation. The volumetric CO{sub 2} transfer coefficient from mixture gas to culture medium was estimated from the volumetric O{sub 2} transfer coefficient obtained experimentally. Using this transfer coefficient and aquatic equilibrium relationship between dissolved inorganic carbons, the behavior of dissolved CO{sub 2} was calculated during microalgal culture. When air containing 0.035%(v/v) CO{sub 2} was supplied into microalgal culture, the fixation rate was limited by CO{sub 2} transfer rate. However, the limitation was disappeared by supplying mixture gas containing above 2%(v/v) CO{sub 2} and the dissolved CO{sub 2} concentration was maintained at the saturated value. In the range of CO{sub 2} partial pressure in the flue gases from thermal power sations and steel-making plants, the microalgal CO{sub 2} fixation rate was inhibited. The CO{sub 2} fixation rate was successfully formulated by a new empirical equation as a function of dissolved CO{sub 2} concentration, which could be useful for modeling and simulating the performance of photobioreaction with enriched CO{sub 2}. Also, it was found that the CO{sub 2} inhibition of microalgal CO{sub 2} fixation was reversible and that microalgal CO{sub 2} fixation process could be stable against a shock of unusually high CO{sub 2} concentration. 29 refs., 8 figs.

  18. Monitoring carbon dioxide in mechanically ventilated patients during hyperbaric treatment

    DEFF Research Database (Denmark)

    Bjerregård, Asger; Jansen, Erik

    2012-01-01

    Measurement of the arterial carbon dioxide (P(a)CO(2)) is an established part of the monitoring of mechanically ventilated patients. Other ways to get information about carbon dioxide in the patient are measurement of end-tidal carbon dioxide (P(ET)CO(2)) and transcutaneous carbon dioxide (PTCCO2......). Carbon dioxide in the blood and cerebral tissue has great influence on vasoactivity and thereby blood volume of the brain. We have found no studies on the correlation between P(ET)CO(2) or P(TC)CO(2), and P(a)CO(2) during hyperbaric oxygen therapy (HBOT)....

  19. Energy efficient solvent regeneration process for carbon dioxide capture

    Science.gov (United States)

    Zhou, Shaojun; Meyer, Howard S.; Li, Shiguang

    2018-02-27

    A process for removing carbon dioxide from a carbon dioxide-loaded solvent uses two stages of flash apparatus. Carbon dioxide is flashed from the solvent at a higher temperature and pressure in the first stage, and a lower temperature and pressure in the second stage, and is fed to a multi-stage compression train for high pressure liquefaction. Because some of the carbon dioxide fed to the compression train is already under pressure, less energy is required to further compress the carbon dioxide to a liquid state, compared to conventional processes.

  20. Economic Evaluations for the Carbon Dioxide-involved Production of High-value Chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Hyun; Lee, Dong Woog; Jang, Se Gyu; Kwak, No-Sang; Lee, In Young; Jang, Kyung Ryoung; Shim, Jae-Goo [KEPCO Research Institute, Daejon (Korea, Republic of); Choi, Jong Shin [Korea East-West Power Co. LTD, Seoul (Korea, Republic of)

    2014-06-15

    Economic evaluation of the manufacturing technology of high-value chemicals through the carbonation reaction of carbon dioxide contained in the flue gas was performed, and analysis of the IRR (Internal Rate of Return) and whole profit along the production plan of the final product was conducted. Through a carbonation reaction with sodium hydroxide that is generated from electrolysis and by using carbon dioxide in the combustion gas that is generated in the power plant, it is possible to get a high value products such as sodium bicarbonate compound and also to reduce the carbon dioxide emission simultaneously. The IRR (Internal Rate of Return) and NPV (Net Present Value) methods were used for the economic evaluation of the process which could handle carbon dioxide of 100 tons per day in the period of the 20 years of plant operation. The results of economic evaluation showed that the IRR of baseline case of technology was 67.2% and the profit that obtained during the whole operation period (20 years) was 346,922 million won based on NPV value. When considering ETS due to the emissions trading enforcement that will be activated in 2015, the NPV was improved to a 6,000 million won. Based on this results, it could be concluded that this CO2 carbonation technology is an cost-effective technology option for the reduction of greenhouse gas.

  1. Economic Evaluations for the Carbon Dioxide-involved Production of High-value Chemicals

    International Nuclear Information System (INIS)

    Lee, Ji Hyun; Lee, Dong Woog; Jang, Se Gyu; Kwak, No-Sang; Lee, In Young; Jang, Kyung Ryoung; Shim, Jae-Goo; Choi, Jong Shin

    2014-01-01

    Economic evaluation of the manufacturing technology of high-value chemicals through the carbonation reaction of carbon dioxide contained in the flue gas was performed, and analysis of the IRR (Internal Rate of Return) and whole profit along the production plan of the final product was conducted. Through a carbonation reaction with sodium hydroxide that is generated from electrolysis and by using carbon dioxide in the combustion gas that is generated in the power plant, it is possible to get a high value products such as sodium bicarbonate compound and also to reduce the carbon dioxide emission simultaneously. The IRR (Internal Rate of Return) and NPV (Net Present Value) methods were used for the economic evaluation of the process which could handle carbon dioxide of 100 tons per day in the period of the 20 years of plant operation. The results of economic evaluation showed that the IRR of baseline case of technology was 67.2% and the profit that obtained during the whole operation period (20 years) was 346,922 million won based on NPV value. When considering ETS due to the emissions trading enforcement that will be activated in 2015, the NPV was improved to a 6,000 million won. Based on this results, it could be concluded that this CO2 carbonation technology is an cost-effective technology option for the reduction of greenhouse gas

  2. Evaluating measurements of carbon dioxide emissions using a precision source--A natural gas burner.

    Science.gov (United States)

    Bryant, Rodney; Bundy, Matthew; Zong, Ruowen

    2015-07-01

    A natural gas burner has been used as a precise and accurate source for generating large quantities of carbon dioxide (CO2) to evaluate emissions measurements at near-industrial scale. Two methods for determining carbon dioxide emissions from stationary sources are considered here: predicting emissions based on fuel consumption measurements-predicted emissions measurements, and direct measurement of emissions quantities in the flue gas-direct emissions measurements. Uncertainty for the predicted emissions measurement was estimated at less than 1%. Uncertainty estimates for the direct emissions measurement of carbon dioxide were on the order of ±4%. The relative difference between the direct emissions measurements and the predicted emissions measurements was within the range of the measurement uncertainty, therefore demonstrating good agreement. The study demonstrates how independent methods are used to validate source emissions measurements, while also demonstrating how a fire research facility can be used as a precision test-bed to evaluate and improve carbon dioxide emissions measurements from stationary sources. Fossil-fuel-consuming stationary sources such as electric power plants and industrial facilities account for more than half of the CO2 emissions in the United States. Therefore, accurate emissions measurements from these sources are critical for evaluating efforts to reduce greenhouse gas emissions. This study demonstrates how a surrogate for a stationary source, a fire research facility, can be used to evaluate the accuracy of measurements of CO2 emissions.

  3. Characterization of carbon dioxide concentrating chemolithotrophic bacterium Serratia sp. ISTD04 for production of biodiesel.

    Science.gov (United States)

    Kumar, Manish; Morya, Raj; Gnansounou, Edgard; Larroche, Christian; Thakur, Indu Shekhar

    2017-11-01

    Proteomics and metabolomics analysis has become a powerful tool for characterization of microbial ability for fixation of Carbon dioxide. Bacterial community of palaeoproterozoic metasediments was enriched in the shake flask culture in the presence of NaHCO 3 . One of the isolate showed resistance to NaHCO 3 (100mM) and was identified as Serratia sp. ISTD04 by 16S rRNA sequence analysis. Carbon dioxide fixing ability of the bacterium was established by carbonic anhydrase enzyme assay along with proteomic analysis by LC-MS/MS. In proteomic analysis 96 proteins were identified out of these 6 protein involved in carbon dioxide fixation, 11 in fatty acid metabolism, indicating the carbon dioxide fixing potency of bacterium along with production of biofuel. GC-MS analysis revealed that hydrocarbons and FAMEs produced by bacteria within the range of C 13 -C 24 and C 11 -C 19 respectively. Presence of 59% saturated and 41% unsaturated organic compounds, make it a better fuel composition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Thermal radiative near field transport between vanadium dioxide and silicon oxide across the metal insulator transition

    Energy Technology Data Exchange (ETDEWEB)

    Menges, F.; Spieser, M.; Riel, H.; Gotsmann, B., E-mail: bgo@zurich.ibm.com [IBM Research-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon (Switzerland); Dittberner, M. [IBM Research-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon (Switzerland); Photonics Laboratory, ETH Zurich, 8093 Zurich (Switzerland); Novotny, L. [Photonics Laboratory, ETH Zurich, 8093 Zurich (Switzerland); Passarello, D.; Parkin, S. S. P. [IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120 (United States)

    2016-04-25

    The thermal radiative near field transport between vanadium dioxide and silicon oxide at submicron distances is expected to exhibit a strong dependence on the state of vanadium dioxide which undergoes a metal-insulator transition near room temperature. We report the measurement of near field thermal transport between a heated silicon oxide micro-sphere and a vanadium dioxide thin film on a titanium oxide (rutile) substrate. The temperatures of the 15 nm vanadium dioxide thin film varied to be below and above the metal-insulator-transition, and the sphere temperatures were varied in a range between 100 and 200 °C. The measurements were performed using a vacuum-based scanning thermal microscope with a cantilevered resistive thermal sensor. We observe a thermal conductivity per unit area between the sphere and the film with a distance dependence following a power law trend and a conductance contrast larger than 2 for the two different phase states of the film.

  5. Made-to-order metal-organic frameworks for trace carbon dioxide removal and air capture

    KAUST Repository

    Shekhah, Osama

    2014-06-25

    Direct air capture is regarded as a plausible alternate approach that, if economically practical, can mitigate the increasing carbon dioxide emissions associated with two of the main carbon polluting sources, namely stationary power plants and transportation. Here we show that metal-organic framework crystal chemistry permits the construction of an isostructural metal-organic framework (SIFSIX-3-Cu) based on pyrazine/copper(II) two-dimensional periodic 4 4 square grids pillared by silicon hexafluoride anions and thus allows further contraction of the pore system to 3.5 versus 3.84 for the parent zinc(II) derivative. This enhances the adsorption energetics and subsequently displays carbon dioxide uptake and selectivity at very low partial pressures relevant to air capture and trace carbon dioxide removal. The resultant SIFSIX-3-Cu exhibits uniformly distributed adsorption energetics and offers enhanced carbon dioxide physical adsorption properties, uptake and selectivity in highly diluted gas streams, a performance, to the best of our knowledge, unachievable with other classes of porous materials. 2014 Macmillan Publishers Limited.

  6. Research Progress in Carbon Dioxide Storage and Enhanced Oil Recovery

    Science.gov (United States)

    Wang, Keliang; Wang, Gang; Lu, Chunjing

    2018-02-01

    With the rapid development of global economy, human beings have become highly dependent upon fossil fuel such as coal and petroleum. Much fossil fuel is consumed in industrial production and human life. As a result, carbon dioxide emissions have been increasing, and the greenhouse effects thereby generated are posing serious threats to environment of the earth. These years, increasing average global temperature, frequent extreme weather events and climatic changes cause material disasters to the world. After scientists’ long-term research, ample evidences have proven that emissions of greenhouse gas like carbon dioxide have brought about tremendous changes to global climate. To really reduce carbon dioxide emissions, governments of different countries and international organizations have invested much money and human resources in performing research related to carbon dioxide emissions. Manual underground carbon dioxide storage and carbon dioxide-enhanced oil recovery are schemes with great potential and prospect for reducing carbon dioxide emissions. Compared with other schemes for reducing carbon dioxide emissions, aforementioned two schemes exhibit high storage capacity and yield considerable economic benefits, so they have become research focuses for reducing carbon dioxide emissions. This paper introduces the research progress in underground carbon dioxide storage and enhanced oil recovery, pointing out the significance and necessity of carbon dioxide-driven enhanced oil recovery.

  7. Pollution from the electric power sector in Japan and efficient pollution reduction

    International Nuclear Information System (INIS)

    Matsushita, Kyohei; Yamane, Fumihiro

    2012-01-01

    Under the scheme of the Kyoto Protocol, there are plans for the efficient reduction of carbon dioxide emissions. In the electric power sector, nuclear power generation, which emits no carbon dioxide in the process of generating electricity, has come under scrutiny. However, this energy produces a new environmental issue: the disposal of radioactive waste. First, we derive shadow prices of carbon dioxide and low-level waste as marginal abatement costs in the case of the electric power sector in Japan, employing a directional output distance function. It is found that the shadow prices are US$39 per tonne for carbon dioxide and US$1531 per liter for low-level waste. Secondly, we calculate the indirect Morishima elasticity between carbon dioxide and low-level waste in order to identify their substitutability, and it is found that the substitution of low-level waste for carbon dioxide is easier than the reverse. This result suggests that, with the amount of generated electricity fixed, carbon dioxide can be substituted more easily by low-level waste when the relative price of carbon dioxide increases, for example, as a result of implementation of a carbon dioxide tax or an emissions trading system.

  8. Uranium Dioxide Powder Flow ability Improvement Using Sol-Gel

    International Nuclear Information System (INIS)

    Juanda, D.; Sambodo Daru, G.

    1998-01-01

    The improvement of flow ability characteristics of uranium dioxide powder has been done using sol-gel process. To anticipate a pellet mass production with uniform pellet dimension, the uranium dioxide powder must be have a spherical form. Uranium dioxide spherical powder has been diluted in acid transformed into sol colloidal solution. To obtain uranium dioxide spherical form, the uranium sol-colloidal solution has been dropped in a hot paraffin ( at the temperature of 90 0 C) to form gelatinous colloid and then dried at 800 0 C, and sintered at the temperature of 1700 0 C. The flow ability of spherical uranium dioxide powder has been examined by using Flowmeter Hall (ASTM. B. 213-46T). The measurement result reveals that the spherical uranium dioxide powder has a flow ability twice than that of unprocessed uranium dioxide powder

  9. Carbon dioxide conversion over carbon-based nanocatalysts.

    Science.gov (United States)

    Khavarian, Mehrnoush; Chai, Siang-Piao; Mohamed, Abdul Rahman

    2013-07-01

    The utilization of carbon dioxide for the production of valuable chemicals via catalysts is one of the efficient ways to mitigate the greenhouse gases in the atmosphere. It is known that the carbon dioxide conversion and product yields are still low even if the reaction is operated at high pressure and temperature. The carbon dioxide utilization and conversion provides many challenges in exploring new concepts and opportunities for development of unique catalysts for the purpose of activating the carbon dioxide molecules. In this paper, the role of carbon-based nanocatalysts in the hydrogenation of carbon dioxide and direct synthesis of dimethyl carbonate from carbon dioxide and methanol are reviewed. The current catalytic results obtained with different carbon-based nanocatalysts systems are presented and how these materials contribute to the carbon dioxide conversion is explained. In addition, different strategies and preparation methods of nanometallic catalysts on various carbon supports are described to optimize the dispersion of metal nanoparticles and catalytic activity.

  10. Simulation of an integrated gasification combined cycle with chemical-looping combustion and carbon dioxide sequestration

    International Nuclear Information System (INIS)

    Jiménez Álvaro, Ángel; López Paniagua, Ignacio; González Fernández, Celina; Rodríguez Martín, Javier; Nieto Carlier, Rafael

    2015-01-01

    Highlights: • A chemical-looping combustion based integrated gasification combined cycle is simulated. • The energetic performance of the plant is analyzed. • Different hydrogen-content synthesis gases are under study. • Energy savings accounting carbon dioxide sequestration and storage are quantified. • A notable increase on thermal efficiency up to 7% is found. - Abstract: Chemical-looping combustion is an interesting technique that makes it possible to integrate power generation from fuels combustion and sequestration of carbon dioxide without energy penalty. In addition, the combustion chemical reaction occurs with a lower irreversibility compared to a conventional combustion, leading to attain a somewhat higher overall thermal efficiency in gas turbine systems. This paper provides results about the energetic performance of an integrated gasification combined cycle power plant based on chemical-looping combustion of synthesis gas. A real understanding of the behavior of this concept of power plant implies a complete thermodynamic analysis, involving several interrelated aspects as the integration of energy flows between the gasifier and the combined cycle, the restrictions in relation with heat balances and chemical equilibrium in reactors and the performance of the gas turbines and the downstream steam cycle. An accurate thermodynamic modeling is required for the optimization of several design parameters. Simulations to evaluate the energetic efficiency of this chemical-looping-combustion based power plant under diverse working conditions have been carried out, and a comparison with a conventional integrated gasification power plant with precombustion capture of carbon dioxide has been made. Two different synthesis gas compositions have been tried to check its influence on the results. The energy saved in carbon capture and storage is found to be significant and even notable, inducing an improvement of the overall power plant thermal efficiency of

  11. Low grade waste heat recovery using heat pumps and power cycles

    International Nuclear Information System (INIS)

    Bor, D.M. van de; Infante Ferreira, C.A.; Kiss, Anton A.

    2015-01-01

    Thermal energy represents a large part of the global energy usage and about 43% of this energy is used for industrial applications. Large amounts are lost via exhaust gases, liquid streams and cooling water while the share of low temperature waste heat is the largest. Heat pumps upgrading waste heat to process heat and cooling and power cycles converting waste heat to electricity can make a strong impact in the related industries. The potential of several alternative technologies, either for the upgrading of low temperature waste heat such as compression-resorption, vapor compression and trans-critical heat pumps, or for the conversion of this waste heat by using organic Rankine, Kalina and trilateral cycle engines, are investigated with regards to energetic and economic performance by making use of thermodynamic models. This study focuses on temperature levels of 45–60 °C as at this temperature range large amounts of heat are rejected to the environment but also investigates the temperature levels for which power cycles become competitive. The heat pumps deliver 2.5–11 times more energy value than the power cycles in this low temperature range at equal waste heat input. Heat engines become competitive with heat pumps at waste heat temperatures at 100 °C and above. - Highlights: • Application of heat pump technology for heating and cooling. • Compression resorption heat pumps operating with large glides approaching 100 K. • Compression-resorption heat pumps with wet compression. • Potential to convert Industrial waste heat to power or high grade heat. • Comparison between low temperature power cycles and heat pumps

  12. SULPHUR DIOXIDE LEACHING OF URANIUM CONTAINING MATERIAL

    Science.gov (United States)

    Thunaes, A.; Rabbits, F.T.; Hester, K.D.; Smith, H.W.

    1958-12-01

    A process is described for extracting uranlum from uranium containing material, such as a low grade pitchblende ore, or mill taillngs, where at least part of the uraniunn is in the +4 oxidation state. After comminuting and magnetically removing any entrained lron particles the general material is made up as an aqueous slurry containing added ferric and manganese salts and treated with sulfur dioxide and aeration to an extent sufficient to form a proportion of oxysulfur acids to give a pH of about 1 to 2 but insufficient to cause excessive removal of the sulfur dioxide gas. After separating from the solids, the leach solution is adjusted to a pH of about 1.25, then treated with metallic iron in the presence of a precipitant such as a soluble phosphate, arsonate, or fluoride.

  13. Anthropogenic sulfur dioxide emissions: 1850–2005

    Directory of Open Access Journals (Sweden)

    S. J. Smith

    2011-02-01

    Full Text Available Sulfur aerosols impact human health, ecosystems, agriculture, and global and regional climate. A new annual estimate of anthropogenic global and regional sulfur dioxide emissions has been constructed spanning the period 1850–2005 using a bottom-up mass balance method, calibrated to country-level inventory data. Global emissions peaked in the early 1970s and decreased until 2000, with an increase in recent years due to increased emissions in China, international shipping, and developing countries in general. An uncertainty analysis was conducted including both random and systemic uncertainties. The overall global uncertainty in sulfur dioxide emissions is relatively small, but regional uncertainties ranged up to 30%. The largest contributors to uncertainty at present are emissions from China and international shipping. Emissions were distributed on a 0.5° grid by sector for use in coordinated climate model experiments.

  14. Thermal properties of nonstoichiometry uranium dioxide

    Science.gov (United States)

    Kavazauri, R.; Pokrovskiy, S. A.; Baranov, V. G.; Tenishev, A. V.

    2016-04-01

    In this paper, was developed a method of oxidation pure uranium dioxide to a predetermined deviation from the stoichiometry. Oxidation was carried out using the thermogravimetric method on NETZSCH STA 409 CD with a solid electrolyte galvanic cell for controlling the oxygen potential of the environment. 4 samples uranium oxide were obtained with a different ratio of oxygen-to-metal: O / U = 2.002, O / U = 2.005, O / U = 2.015, O / U = 2.033. For the obtained samples were determined basic thermal characteristics of the heat capacity, thermal diffusivity, thermal conductivity. The error of heat capacity determination is equal to 5%. Thermal diffusivity and thermal conductivity of the samples decreased with increasing deviation from stoichiometry. For the sample with O / M = 2.033, difference of both values with those of stoichiometric uranium dioxide is close to 50%.

  15. Measurement of nitrogen dioxide in the air

    Energy Technology Data Exchange (ETDEWEB)

    Monteriolo, S C; Bertolaccini, M A

    1973-01-01

    A comparative study of automatic analytical methods for the monitoring of nitric oxide and nitrogen dioxide in the air indicates the need for a correct chemical conversion of the nonmeasurable species into the measurable species to obtain dependable results. The automatic colorimetric and chemiluminescent methods were compared to the manual colorimeter, and the electrochemical method was compared to chemiluminescence. Average, minimum, and maximum values are given for each comparison. All three methods are equally valid, in response linearity, sensitivity, and concentration limit, for the determination of nitric oxide, the measurable species. The determination of nitrogen dioxide, however, is strictly dependent on the efficiency of the conversion of the non-measurable species into the measurable form.

  16. Recycling technology of emitted carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Arakawa, Hironori [National Inst. of Materials and Chemical Research (NIMC), Ibaraki (Japan)

    1993-12-31

    Ways to halt global warming are being discussed worldwide. Global warming is an energy problem which is mainly attributed to the large volumes of carbon dioxide (CO{sub 2}) released into the atmosphere from the rapid increase in energy consumption since the Industrial Revolution. The basic solution to the problem, therefore, is to cut consumption of fossil fuels. To this end, it is important to promote energy conservation by improving the fuel efficiency of machines, as well as shift to energy sources that do not emit carbon dioxide and develop related technologies. If current trends in economic growth continue in the devloping world as well as the developed countries, there can be no doubt that energy consumption will increase. Therefore, alongside energy conservation and the development of alternative energies, the importance of technologies to recover and fix CO{sub 2} will increase in the fight against global warming.

  17. Carbon dioxide may become a resource

    International Nuclear Information System (INIS)

    Haugneland, Petter; Areklett, Ivar

    2002-01-01

    The greenhouse gas CO 2 may become a product that the oil companies would pay for. In an extensive international resource project methods for CO 2 capture, transport and storage are being investigated. CO 2 capture means that carbon dioxide that is formed in the combustion of fossil fuels is separated out from the process, either from the fuel (decarbonization), or from the flue gas, and then stored. The article briefly describes the international joint project CO 2 Capture Project (CCP), in which eight oil companies are participating. If one can find a method for injecting CO 2 into oil reservoirs that leads to increased oil production, then part of the extra cost of removing the carbon dioxide from flue gas may be repaid

  18. Structure of zirconium dioxide based porous glasses

    Czech Academy of Sciences Publication Activity Database

    Gubanova, N. N.; Kopitsa, G. P.; Ezdakova, K. V.; Baranchikov, A. Y.; Angelov, Borislav; Feoktystov, A.; Pipich, V.; Ryukhtin, Vasyl; Ivanov, V. K.

    2014-01-01

    Roč. 8, č. 5 (2014), s. 967-975 ISSN 1027-4510 R&D Projects: GA ČR GAP208/10/1600; GA MŠk(XE) LM2011019; GA ČR GB14-36566G Institutional support: RVO:61389013 ; RVO:61389005 Keywords : zirconium dioxide * porous glasse * nanoparticles Subject RIV: CF - Physical ; Theoretical Chemistry; BG - Nuclear, Atomic and Molecular Physics, Colliders (UJF-V) Impact factor: 0.359, year: 2012

  19. Direct carbon dioxide emissions from civil aircraft

    OpenAIRE

    Grote, Matt; Williams, Ian; Preston, John

    2014-01-01

    Global airlines consume over 5 million barrels of oil per day, and the resulting carbon dioxide (CO2) emitted by aircraft engines is of concern. This article provides a contemporary review of the literature associated with the measures available to the civil aviation industry for mitigating CO2 emissions from aircraft. The measures are addressed under two categories – policy and legal-related measures, and technological and operational measures. Results of the review are used to develop sever...

  20. Anodic growth of titanium dioxide nanostructures

    DEFF Research Database (Denmark)

    2010-01-01

    Disclosed is a method of producing nanostructures of titanium dioxide (TiO 2 ) by anodisation of titanium (Ti) in an electrochemical cell, comprising the steps of: immersing a non-conducting substrate coated with a layer of titanium, defined as the anode, in an electrolyte solution...... an electrical contact to the layer of titanium on the anode, where the electrical contact is made in the electrolyte solution...

  1. Titanium dioxide modified with various amines used as sorbents of carbon dioxide

    International Nuclear Information System (INIS)

    Kapica-Kozar, Joanna; Pirog, Ewa; Kusiak-Nejman, Ewelina; Wrobel, Rafal J.; Gesikiewicz-Puchalska, Andzelika; Morawski, Antoni W.; Narkiewicz, Urszula; Michalkiewicz, Beata

    2017-01-01

    In this study, titanium dioxide was modified with various amines through hydrothermal treatment for adsorption of CO_2. The carbon dioxide adsorption performance of the prepared samples was measured using an STA 449 C thermo-balance (Netzsch Company, Germany). The morphological structures, functional groups and elemental compositions of the unmodified and amine-modified titanium dioxide sorbents were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR/DR) and scanning electron microscopy (SEM), respectively. The results showed that modification of TiO_2 with amines through hydrothermal treatment is a simple method to prepare CO_2 sorbents with high adsorption capacities. Moreover, the results revealed that TEPA-modified titanium dioxide shoved the highest adsorption capacity, enabling an increase in CO_2 uptake from 0.45 mmol CO_2 g"-"1 in the case of raw TiO_2 to 1.63 mmol CO_2 g"-"1. This result could be indirectly related to the fact that TEPA has the highest amino group content among the three amines used in our research. Additionally, durability tests performed by cyclic adsorption-desorption revealed that TEPA modified titanium dioxide also possesses excellent stability, despite a slight decrease in adsorption capacity over time. (authors)

  2. Biological effects data: Fluoride and sulfur dioxide

    Energy Technology Data Exchange (ETDEWEB)

    McMechan, K.J. (ed.); Holton, R.L.; Ulbricht, R.J.; Morgan , J.B.

    1975-04-01

    The Alumax Pacific Aluminum Corporation has proposed construction of an aluminum reduction facility near Youngs Bay at Warrenton, Oregon. This report comprises one part of the final report to Alumax on a research project entitled, Physical, Chemical and Biological Studies of Youngs Bay.'' It presents data pertaining to the potential biological effects of fluoride and sulfur dioxide, two potentially hazardous plant-stack emissions, on selected aquatic species of the area. Companion volumes provide a description of the physical characteristics the geochemistry, and the aquatic animals present in Youngs Bay and adjacent ecosystems. An introductory volume provides general information and maps of the area, and summarizes the conclusions of all four studies. The data from the two phases of the experimental program are included in this report: lethal studies on the effects of selected levels of fluoride and sulfur dioxide on the survival rate of eleven Youngs Bay faunal species from four phyla, and sublethal studies on the effects of fluoride and sulfur dioxide on the rate of primary production of phytoplankton. 44 refs., 18 figs., 38 tabs.

  3. Carbon isotope ratios of atmospheric carbon dioxide

    International Nuclear Information System (INIS)

    Sakai, Hitoshi; Kishima, Noriaki; Tsutaki, Yasuhiro.

    1982-01-01

    The delta 13 C values relative to PDB were measured for carbon dioxide in air samples collected at various parts of Japan and at Mauna Loa Observatory, Hawaii in the periods of 1977 and 1978. The delta 13 C values of the ''clean air'' are -7.6 % at Hawaii and -8.1 per mille Oki and Hachijo-jima islands. These values are definitely lighter than the carbon isotope ratios (-6.9 per mille) obtained by Keeling for clean airs collected at Southern California in 1955 to 1956. The increase in 12 C in atmospheric carbon dioxide is attributed to the input of the anthropogenic light carbon dioxides (combustion of fossil fuels etc.) Taking -7.6 per mille to be the isotope ratio of CO 2 in the present clean air, a simple three box model predicts that the biosphere has decreased rather than increased since 1955, implying that it is acting as the doner of carbon rather than the sink. (author)

  4. Electrocatalytic process for carbon dioxide conversion

    Science.gov (United States)

    Masel, Richard I.; Salehi-Khojin, Amin; Kutz, Robert

    2017-11-14

    An electrocatalytic process for carbon dioxide conversion includes combining a Catalytically Active Element and a Helper Polymer in the presence of carbon dioxide, allowing a reaction to proceed to produce a reaction product, and applying electrical energy to said reaction to achieve electrochemical conversion of said carbon dioxide reactant to said reaction product. The Catalytically Active Element can be a metal in the form of supported or unsupported particles or flakes with an average size between 0.6 nm and 100 nm. The reaction products comprise at least one of CO, HCO.sup.-, H.sub.2CO, (HCO.sub.2).sup.-, H.sub.2CO.sub.2, CH.sub.3OH, CH.sub.4, C.sub.2H.sub.4, CH.sub.3CH.sub.2OH, CH.sub.3COO.sup.-, CH.sub.3COOH, C.sub.2H.sub.6, (COOH).sub.2, (COO.sup.-).sub.2, and CF.sub.3COOH.

  5. Carbon dioxide in Arctic and subarctic regions

    Energy Technology Data Exchange (ETDEWEB)

    Gosink, T. A.; Kelley, J. J.

    1981-03-01

    A three year research project was presented that would define the role of the Arctic ocean, sea ice, tundra, taiga, high latitude ponds and lakes and polar anthropogenic activity on the carbon dioxide content of the atmosphere. Due to the large physical and geographical differences between the two polar regions, a comparison of CO/sub 2/ source and sink strengths of the two areas was proposed. Research opportunities during the first year, particularly those aboard the Swedish icebreaker, YMER, provided additional confirmatory data about the natural source and sink strengths for carbon dioxide in the Arctic regions. As a result, the hypothesis that these natural sources and sinks are strong enough to significantly affect global atmospheric carbon dioxide levels is considerably strengthened. Based on the available data we calculate that the whole Arctic region is a net annual sink for about 1.1 x 10/sup 15/ g of CO/sub 2/, or the equivalent of about 5% of the annual anthropogenic input into the atmosphere. For the second year of this research effort, research on the seasonal sources and sinks of CO/sub 2/ in the Arctic will be continued. Particular attention will be paid to the seasonal sea ice zones during the freeze and thaw periods, and the tundra-taiga regions, also during the freeze and thaw periods.

  6. Determination of diffusion coefficients of carbon dioxide in water between 268 and 473 K in a high-pressure capillary optical cell with in situ Raman spectroscopic measurements

    Science.gov (United States)

    Lu, Wanjun; Guo, Huirong; Chou, I.-Ming; Burruss, R.C.; Li, Lanlan

    2013-01-01

    Accurate values of diffusion coefficients for carbon dioxide in water and brine at reservoir conditions are essential to our understanding of transport behavior of carbon dioxide in subsurface pore space. However, the experimental data are limited to conditions at low temperatures and pressures. In this study, diffusive transfer of carbon dioxide in water at pressures up to 45 MPa and temperatures from 268 to 473 K was observed within an optical capillary cell via time-dependent Raman spectroscopy. Diffusion coefficients were estimated by the least-squares method for the measured variations in carbon dioxide concentration in the cell at various sample positions and time. At the constant pressure of 20 MPa, the measured diffusion coefficients of carbon dioxide in water increase with increasing temperature from 268 to 473 K. The relationship between diffusion coefficient of carbon dioxide in water [D(CO2) in m2/s] and temperature (T in K) was derived with Speedy–Angell power-law approach as: D(CO2)=D0[T/Ts-1]m where D0 = 13.942 × 10−9 m2/s, Ts = 227.0 K, and m = 1.7094. At constant temperature, diffusion coefficients of carbon dioxide in water decrease with pressure increase. However, this pressure effect is rather small (within a few percent).

  7. Calculation of the characteristics of carbon dioxide TEA photoionization lasers

    Energy Technology Data Exchange (ETDEWEB)

    Aver' yanov, N E; Baloshin, Yu A; Gerke, M N; Dernyatin, A I; Khurgin, Ya B

    1979-01-01

    A mathematical model is proposed for studying the characteristics of a carbon dioxide photoionization laser with pressures of the active mixture of the order of one atmosphere. The kinetics of the CO/sub 2/ molecules is described in terms of population of the group of lower vibrational levels. The part played by N/sub 2/ molecules in the general system of kinetic equations is accounted for by a harmonic oscillator model with Boltzmann population of vibrational levels and the corresponding vibrational temperature. A diagram is given of the fundamental kinetic processes in the proposed model for a TEA laser. The results of calculations are compared with a previously proposed model and with experimental data for a carbon dioxide TEA photoionization laser using preionization by ultraviolet radiation and operating in the semi-selfmaintained discharge mode. The active mixture was CO/sub 2/:N/sub 2/:He=1:1:8. It was found that optimum mixtures for maximum power are those with ratios of CO/sub 2/:N/sub 2/He=5:45:50, 10:40:50 and 5:55:40. The helium molecules supply most of the photoelectrons, and the additives give a uv spectrum that is optimum for photoionization of He. The CO/sub 2/ is the lasing molecule, but absorbs uv radiation, and therefore the optimum CO/sub 2/ concentration is low. The influence that dissociation of CO/sub 2/ molecules has on the laser depends on the electron concentration in the main discharge. Any model that reliably describes laser characteristics must take account of dissociation of the lasing molecules by means of some factor that shows how many molecules are dissociated by uv radiation, although the dissociation by electron impact can be disregarded.

  8. International power projections and capital requirements

    International Nuclear Information System (INIS)

    Ann, H.

    1989-01-01

    This work is related to the international power projections and capital requirements of all kinds of energy and the share of electricity. It is also related to the so-called greenhouse effect carbon dioxide concentration in atmosphere. (A.C.A.S.)

  9. Reducing nitrogen oxides from power stations

    International Nuclear Information System (INIS)

    Scheller, W.

    1986-12-01

    The report contains 17 individual lectures of the seminar included in databanks. The lectures concern combustion and waste gas measures for reducing the sulfur dioxide and nitrogen oxide emission from coal-fired and gas-fired power stations. (PW) [de

  10. Analysis of pipeline transportation systems for carbon dioxide sequestration

    Directory of Open Access Journals (Sweden)

    Witkowski Andrzej

    2014-03-01

    Full Text Available A commercially available ASPEN PLUS simulation using a pipe model was employed to determine the maximum safe pipeline distances to subsequent booster stations as a function of carbon dioxide (CO2 inlet pressure, ambient temperature and ground level heat flux parameters under three conditions: isothermal, adiabatic and with account of heat transfer. In the paper, the CO2 working area was assumed to be either in the liquid or in the supercritical state and results for these two states were compared. The following power station data were used: a 900 MW pulverized coal-fired power plant with 90% of CO2 recovered (156.43 kg/s and the monothanolamine absorption method for separating CO2 from flue gases. The results show that a subcooled liquid transport maximizes energy efficiency and minimizes the cost of CO2 transport over long distances under isothermal, adiabatic and heat transfer conditions. After CO2 is compressed and boosted to above 9 MPa, its temperature is usually higher than ambient temperature. The thermal insulation layer slows down the CO2 temperature decrease process, increasing the pressure drop in the pipeline. Therefore in Poland, considering the atmospheric conditions, the thermal insulation layer should not be laid on the external surface of the pipeline.

  11. Analysis of pipeline transportation systems for carbon dioxide sequestration

    Science.gov (United States)

    Witkowski, Andrzej; Majkut, Mirosław; Rulik, Sebastian

    2014-03-01

    A commercially available ASPEN PLUS simulation using a pipe model was employed to determine the maximum safe pipeline distances to subsequent booster stations as a function of carbon dioxide (CO2) inlet pressure, ambient temperature and ground level heat flux parameters under three conditions: isothermal, adiabatic and with account of heat transfer. In the paper, the CO2 working area was assumed to be either in the liquid or in the supercritical state and results for these two states were compared. The following power station data were used: a 900 MW pulverized coal-fired power plant with 90% of CO2 recovered (156.43 kg/s) and the monothanolamine absorption method for separating CO2 from flue gases. The results show that a subcooled liquid transport maximizes energy efficiency and minimizes the cost of CO2 transport over long distances under isothermal, adiabatic and heat transfer conditions. After CO2 is compressed and boosted to above 9 MPa, its temperature is usually higher than ambient temperature. The thermal insulation layer slows down the CO2 temperature decrease process, increasing the pressure drop in the pipeline. Therefore in Poland, considering the atmospheric conditions, the thermal insulation layer should not be laid on the external surface of the pipeline.

  12. The effects of low level chlorination and chlorine dioxide on biofouling control in a once-through service water system

    International Nuclear Information System (INIS)

    Garrett, W.E. Jr.; Laylor, M.M.

    1995-01-01

    Continuous chlorination has been successfully used for the control of Corbicula at a nuclear power plant located on the Chattahoochee River in southeastern Alabama, since 1986. The purpose of this study was to investigate further minimization of chlorine usage and determine if chlorine dioxide is a feasible alternative. Four continuous biocide treatments were evaluated for macro and microfouling control effectiveness, operational feasibility, and environmental acceptability. One semi-continuous chlorination treatment was also evaluated for macrofouling control effectiveness. Higher treatment residuals were possible with chlorine dioxide than with chlorination due to the river discharge limitations. At the levels tested, continuous chlorine dioxide was significantly more effective in providing both macro and microfouling control. Semi-continuous chlorination was just as effective as continuous chlorination for controlling macrofouling. The Corbicula treatment programs that were tested should all provide sufficient control for zebra mussels. Chlorine dioxide was not as cost effective as chlorination for providing macrofouling control. The semi-continuous treatment save 50% on chemical usage and will allow for the simultaneous treatment of two service water systems. Chlorite levels produced during the chlorine dioxide treatments were found to be environmentally acceptable. Levels of trihalomethanes in the chlorinated service water were less than the maximum levels allowed in drinking water

  13. Effects of changes in the UK energy demand and environmental legislation on atmospheric pollution by sulphur dioxide

    International Nuclear Information System (INIS)

    Blakemore, F.B.; Davies, C.; Isaac, J.G.

    1999-01-01

    Ninety-nine percent of the sulphur dioxide generated over the period 1970 to 1994 arose from the combustion of fossil fuels in the energy sector. The annual mass emission of sulphur dioxide has fallen by 58% over this period, due to the reductions in outputs from coal and petroleum fired plants. The influence of natural-gas power generation has played an important part in this reduction. Four major pieces of environmental legislation have been enacted to control sulphur-dioxide emissions: the Control of Pollution Act 1974, and three EEC Directives are discussed. The UK emissions in 1994 were 49% below the 1980 baseline and 9% ahead of the 1998 EU target level. The protocol on the reduction of sulphur-dioxide emissions, adopted in 1985, required a cut in the total SO 2 emissions of 30% by 1993, based on 1980 levels. The UK achieved a reduction of 37% by the end of 1993. Sulphur-dioxide emissions are predicted to fall according to the six scenarios in Energy paper 65 as a reference case. The predicted decline is in line with the UNECE targets set for 2010. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  14. Experiment Plan of High Temperature Steam and Carbon dioxide Co-electrolysis for Synthetic Gas Production

    International Nuclear Information System (INIS)

    Yoon, Duk-Joo; Ko, Jae-Hwa

    2008-01-01

    Currently, Solid oxide fuel cells (SOFC) come into the spotlight in the middle of the energy technologies of the future for highly effective conversion of fossil fuels into electricity without carbon dioxide emission. The SOFC is a reversible cell. By applying electrical power to the cell, which is solid oxide electrolysis cell (SOEC), it is possible to produce synthetic gas (syngas) from high temperature steam and carbon dioxide. The produced syngas (hydrogen and carbon monoxide) can be used for synthetic fuels. This SOEC technology can use high temperature from VHTRs for high efficiency. This paper describes KEPRI's experiment plan of high temperature steam and carbon co-electrolysis for syngas production using SOEC technology

  15. Ordered mesoporous silica (OMS) as an adsorbent and membrane for separation of carbon dioxide (CO2).

    Science.gov (United States)

    Chew, Thiam-Leng; Ahmad, Abdul L; Bhatia, Subhash

    2010-01-15

    Separation of carbon dioxide (CO(2)) from gaseous mixture is an important issue for the removal of CO(2) in natural gas processing and power plants. The ordered mesoporous silicas (OMS) with uniform pore structure and high density of silanol groups, have attracted the interest of researchers for separation of carbon dioxide (CO(2)) using adsorption process. These mesoporous silicas after functionalization with amino groups have been studied for the removal of CO(2). The potential of functionalized ordered mesoporous silica membrane for separation of CO(2) is also recognized. The present paper reviews the synthesis of mesoporous silicas and important issues related to the development of mesoporous silicas. Recent studies on the CO(2) separation using ordered mesoporous silicas (OMS) as adsorbent and membrane are highlighted. The future prospectives of mesoporous silica membrane for CO(2) adsorption and separation are also presented and discussed. Copyright 2009 Elsevier B.V. All rights reserved.

  16. Simulation scenarios for rapid reduction in carbon dioxide emissions in the western electricity system

    International Nuclear Information System (INIS)

    Ford, Andrew

    2008-01-01

    This paper describes a computer simulation analysis of carbon dioxide emissions in the electric power system in the western United States. Legislation at both the state and federal level would impose a price on emissions via cap-and-trade in allowances for carbon dioxide emissions. The simulation scenarios for the western system indicate that dramatic reductions in emissions are possible with generating technologies that exist today. Wind and biomass generators play a key role even with conservative assumptions about their future costs. In contrast, generation from advanced technologies provide only a minor contribution by the year 2025. These scenarios provide support to those who argue that the US should move expeditiously to put a price on carbon dixoide emissions

  17. Synthesis of dye-sensitized solar cells. Efficiency cells as a thickness of titanium dioxide

    Directory of Open Access Journals (Sweden)

    Szura Dominika

    2017-01-01

    Full Text Available Defying the influence of the thickness of TiO2 efficiency of dye-sensitized solar cell. It was confirmed that the compatibility of printed layers with the parameters closely related with the DSSC. It was found that the increase in thickness of the titanium dioxide layer, increases the distance between the electrodes, determined by the thickness of the Surlyn foil. With the rise of thickness of dyed layer of TiO2 established decrease in the value of its transmittance. Greatest transparency and aesthetic value obtained for photovoltaic modules with a single layer of titanium dioxide. The improved performance efficiency and preferred yields maximum power were noticed and exhibited by the cells covered with three layers of TiO2. It was established that the behaviour of economic efficiency in the production process, provides a range of cells with two layers of oxide, showing a similar performance and greater transparency.

  18. The carbon dioxide thermometer and the cause of global warming

    International Nuclear Information System (INIS)

    Calder, Nigel

    1999-01-01

    Carbon dioxide in the air may be increasing because the world is warming. This possibility, which contradicts the hypothesis of an enhanced greenhouse warming driven by manmade emissions, is here pursued in two ways. First, increments in carbon dioxide are treated as readings of a natural thermometer that tracks global and hemispheric temperature deviations, as gauged by meteorologists' thermometers. Calibration of the carbon dioxide thermometer to conventional temperatures then leads to a history of carbon dioxide since 1856 that diverges from the ice-core record. Secondly, the increments of carbon dioxide can also be accounted for, without reference to temperature, by the combined effects of cosmic rays, El Nino and volcanoes. The most durable effect is due to cosmic rays. A solar wind history, used as a long-term proxy for the cosmic rays, gives a carbon dioxide history similar to that inferred from the global temperature deviations. (author)

  19. Amperometric sensor for carbon dioxide: design, characteristics, and perforance

    International Nuclear Information System (INIS)

    Evans, J.; Pletcher, D.; Warburton, P.R.G.; Gibbs, T.K.

    1989-01-01

    A new sensor for atmospheric carbon dioxide is described. It is an amperometric device based on a porous electrode in a three-electrode cell and the electrolyte is a copper diamine complex in aqueous potassium chloride. The platinum cathode, held at constant potential, is used to detect the formation of Cu 2+ following the change in the pH of the solution when the sensor is exposed to an atmosphere containing carbon dioxide. The sensor described is designed to monitor carbon dioxide concentrations in the range 0-5%, although with some modifications, other ranges would be possible. The response to a change in the carbon dioxide content of the atmosphere is rapid (about 10s) while the monitored current is strongly (but nonlinearly) dependent on carbon dioxide concentration. Unlike other amperometric devices for carbon dioxide, there is no interference from oxygen although other acid gases would lead to an interfering response

  20. Effects of carbon dioxide on Penicillium chrysogenum: an autoradiographic study

    International Nuclear Information System (INIS)

    Edwards, A.G.; Ho, C.S.

    1988-01-01

    Previous research has shown that dissolved carbon dioxide causes significant changes in submerged penicillin fermentations, such as stunted, swollen hyphae, increased branching, lower growth rates, and lower penicillin productivity. Influent carbon dioxide levels of 5 and 10% were shown through the use of autoradiography to cause an increase in chitin synthesis in submerged cultures of Penicillium chrysogenum. At an influent 5% carbon dioxide level, chitin synthesis is ca. 100% greater in the subapical region of P. chrysogenum hyphae than that of the control, in which there was no influent carbon dioxide. Influent carbon dioxide of 10% caused an increase of 200% in chitin synthesis. It is believed that the cell wall must be plasticized before branching can occur and that high amounts of dissolved carbon dioxide cause the cell to lose control of the plasticizing effect, thus the severe morphological changes occur

  1. Nuclear power and the greenhouse effect

    International Nuclear Information System (INIS)

    Donaldson, D; Tolland, H.; Grimston, M.

    1990-01-01

    The greenhouse effect is first explained. The evidence is shown in global warming and changing weather patterns which are generally believed to be due to the emission of greenhouse gases, including carbon dioxide. Serious consequences are predicted if emission of the greenhouse gases is not reduced. Sources of these gases are identified - agriculture, carbon fluorocarbons, coal-fired power stations, vehicle exhausts. The need is to use energy more efficiently but such measures as combined heat and power stations, more fuel efficient cars and better thermal insulation in homes is advocated. The expansion of renewable energy sources such as wind and water power is also suggested. Nuclear power is promoted as it reduces the carbon dioxide emissions and in both the short and long-term will reduce the emission of greenhouse gases. (author)

  2. Environment and nuclear power

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    Aimed at the general public this leaflet, one of a series prepared by AEA Technology, on behalf of the British Nuclear Industry Forum, seeks to put the case for generating electricity to meet United Kingdom and world demand using nuclear power. It examines the environmental problems linked to the use of fossil-fuels in power stations and other uses, such as the Greenhouse Effect. Problems associated with excess carbon dioxide emissions are also discussed, such as acid rain, the effects of deforestation and lead in petrol. The role of renewable energy sources is mentioned briefly. The leaflet also seeks to reassure on issues such as nuclear waste managements and the likelihood and effects of nuclear accidents. (UK)

  3. Adverse effects of the automotive industry on carbon dioxide emissions

    OpenAIRE

    Mpho Bosupeng

    2016-01-01

    This study aims to determine the effects of the automotive industry on carbon dioxide emissions for the period from 1997 to 2010 for diverse economies, as well as the relationships between carbon dioxide discharges and output. The study applies cointegration and causality tests to validate these associations. The results of the Johansen cointegration test depict long-run associations between the quantity of passenger cars and carbon dioxide emissions in France, Sweden, Spain, Hungary and Japa...

  4. On reaction of titanium polonides with carbon dioxide

    International Nuclear Information System (INIS)

    Abakumov, A.S.; Malyshev, M.L.; Reznikova, N.F.

    1986-01-01

    The reaction between titanium polonides and carbon dioxide has been studied by comparing titanium polonide thermal resistance in vacuum and in carbon dioxide. The investigation has shown that titanium mono- and semipolonides fail at temperatures below 350 deg C. Temperature dependence of polonium vapor pressure prepared at failure of the given polonides is determined by the radiotensiometry in carbon dioxide. Enthalpy calculated for this dependence is close to the enthalpy of elementary polonium evaporation in vacuum

  5. The removal of phenols from oily wastewater by chlorine dioxide

    OpenAIRE

    Hsu, Chung-Jung

    1988-01-01

    Treatability studies were performed on oily wastewaters produced by petroleum and canning industries. Chlorine dioxide was used for the removal of phenolic compounds from these oily wastewaters. Most of phenolic compounds can be destroyed by chlorine dioxide within 15 minutes if CI02-to-phenol ratios of higher than 5.0 are provided. Factors such as pH, temperature, and COD have little effect on phenol removal. The effectiveness of chlorine dioxide treatment depends critic...

  6. Design Construction and Operation of a Supercritical Carbon Dioxide (sCO2) Loop for Investigation of Dry Cooling and Natural Circulation Potential for Use in Advanced Small Modular Reactors Utilizing sCO2 Power Conversion Cycles.

    Energy Technology Data Exchange (ETDEWEB)

    Middleton, Bobby D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rodriguez, Salvador B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Carlson, Matthew David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    This report outlines the work completed for a Laboratory Directed Research and Development project at Sandia National Laboratories from October 2012 through September 2015. An experimental supercritical carbon dioxide (sCO 2 ) loop was designed, built, and o perated. The experimental work demonstrated that sCO 2 can be uti lized as the working fluid in an air - cooled, natural circulation configuration to transfer heat from a source to the ultimate heat sink, which is the surrounding ambient environment in most ca ses. The loop was also operated in an induction - heated, water - cooled configuration that allows for measurements of physical parameters that are difficult to isolate in the air - cooled configuration. Analysis included the development of two computational flu id dynamics models. Future work is anticipated to answer questions that were not covered in this project.

  7. Changes in plasma potassium concentration during carbon dioxide pneumoperitoneum

    DEFF Research Database (Denmark)

    Perner, A; Bugge, K; Lyng, K M

    1999-01-01

    Hyperkalaemia with ECG changes had been noted during prolonged carbon dioxide pneumoperitoneum in pigs. We have compared plasma potassium concentrations during surgery in 11 patients allocated randomly to undergo either laparoscopic or open appendectomy and in another 17 patients allocated randomly...... to either carbon dioxide pneumoperitoneum or abdominal wall lifting for laparoscopic colectomy. Despite an increasing metabolic acidosis, prolonged carbon dioxide pneumoperitoneum resulted in only a slight increase in plasma potassium concentrations, which was both statistically and clinically insignificant....... Thus hyperkalaemia is unlikely to develop in patients with normal renal function undergoing carbon dioxide pneumoperitoneum for laparoscopic surgery....

  8. Selective free radical reactions using supercritical carbon dioxide.

    Science.gov (United States)

    Cormier, Philip J; Clarke, Ryan M; McFadden, Ryan M L; Ghandi, Khashayar

    2014-02-12

    We report herein a means to modify the reactivity of alkenes, and particularly to modify their selectivity toward reactions with nonpolar reactants (e.g., nonpolar free radicals) in supercritical carbon dioxide near the critical point. Rate constants for free radical addition of the light hydrogen isotope muonium to ethylene, vinylidene fluoride, and vinylidene chloride in supercritical carbon dioxide are compared over a range of pressures and temperatures. Near carbon dioxide's critical point, the addition to ethylene exhibits critical speeding up, while the halogenated analogues display critical slowing. This suggests that supercritical carbon dioxide as a solvent may be used to tune alkene chemistry in near-critical conditions.

  9. Mechanism of the toxic action of sulfur dioxide on plants

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaevskii, V S; Miroshnikova, A T; Firger, V V; Belokrylova, L M

    1975-01-01

    Experiments were performed to determine the effects of sulfur dioxide on U CO2 metabolism and photosynthesis in fescue and timothy grass and in maple and barberry branches. The free radical inhibitors, ascorbic acid and thiourea, were found to decrease the damaging effects of the sulfur dioxide. These results indicated that the processes involved are of the free-radical chain type. Even at low sulfur dioxide concentrations, photosphosphorylation and carbon dioxide assimilation were inhibited. In addition, starch and protein as well as the formation of polymeric substances were also inhibited.

  10. Carbon dioxide absorbent and method of using the same

    Science.gov (United States)

    Perry, Robert James; O'Brien, Michael Joseph

    2014-06-10

    In accordance with one aspect, the present invention provides a composition which contains the amino-siloxane structures I, or III, as described herein. The composition is useful for the capture of carbon dioxide from process streams. In addition, the present invention provides methods of preparing the amino-siloxane composition. Another aspect of the present invention provides methods for reducing the amount of carbon dioxide in a process stream employing the amino-siloxane compositions of the invention, as species which react with carbon dioxide to form an adduct with carbon dioxide.

  11. Carbon dioxide absorbent and method of using the same

    Energy Technology Data Exchange (ETDEWEB)

    Perry, Robert James; O' Brien, Michael Joseph

    2015-12-29

    In accordance with one aspect, the present invention provides a composition which contains the amino-siloxane structures I, or III, as described herein. The composition is useful for the capture of carbon dioxide from process streams. In addition, the present invention provides methods of preparing the amino-siloxane composition. Another aspect of the present invention provides methods for reducing the amount of carbon dioxide in a process stream employing the amino-siloxane compositions of the invention, as species which react with carbon dioxide to form an adduct with carbon dioxide.

  12. Carbon Dioxide Separation Using Thermally Optimized Membranes

    Science.gov (United States)

    Young, J. S.; Jorgensen, B. S.; Espinoza, B. F.; Weimer, M. W.; Jarvinen, G. D.; Greenberg, A.; Khare, V.; Orme, C. J.; Wertsching, A. K.; Peterson, E. S.; Hopkins, S. D.; Acquaviva, J.

    2002-05-01

    The purpose of this project is to develop polymeric-metallic membranes for carbon dioxide separations that operate under a broad range of industrially relevant conditions not accessible with present membrane units. The last decade has witnessed a dramatic increase in the use of polymer membranes as an effective, economic and flexible tool for many commercial gas separations including air separation, the recovery of hydrogen from nitrogen, carbon monoxide, and methane mixtures, and the removal of carbon dioxide from natural gas. In each of these applications, high fluxes and excellent selectivities have relied on glassy polymer membranes which separate gases based on both size and solubility differences. To date, however, this technology has focused on optimizing materials for near ambient conditions. The development of polymeric materials that achieve the important combination of high selectivity, high permeability, and mechanical stability at temperatures significantly above 25oC and pressures above 10 bar, respectively, has been largely ignored. Consequently, there is a compelling rationale for the exploration of a new realm of polymer membrane separations. Indeed, the development of high temperature polymeric-metallic composite membranes for carbon dioxide separation at temperatures of 100-450 oC and pressures of 10-150 bar would provide a pivotal contribution with both economic and environmental benefits. Progress to date includes the first ever fabrication of a polymeric-metallic membrane that is selective from room temperature to 370oC. This achievement represents the highest demonstrated operating temperature at which a polymeric based membrane has successfully functioned. Additionally, we have generated the first polybenzamidizole silicate molecular composites. Finally, we have developed a technique that has enabled the first-ever simultaneous measurements of gas permeation and membrane compaction at elevated temperatures. This technique provides a unique

  13. Pyrochemical reduction of uranium dioxide and plutonium dioxide by lithium metal

    International Nuclear Information System (INIS)

    Usami, T.; Kurata, M.; Inoue, T.; Sims, H.E.; Beetham, S.A.; Jenkins, J.A.

    2002-01-01

    The lithium reduction process has been developed to apply a pyrochemical recycle process for oxide fuels. This process uses lithium metal as a reductant to convert oxides of actinide elements to metal. Lithium oxide generated in the reduction would be dissolved in a molten lithium chloride bath to enhance reduction. In this work, the solubility of Li 2 O in LiCl was measured to be 8.8 wt% at 650 deg. C. Uranium dioxide was reduced by Li with no intermediate products and formed porous metal. Plutonium dioxide including 3% of americium dioxide was also reduced and formed molten metal. Reduction of PuO 2 to metal also occurred even when the concentration of lithium oxide was just under saturation. This result indicates that the reduction proceeds more easily than the prediction based on the Gibbs free energy of formation. Americium dioxide was also reduced at 1.8 wt% lithium oxide, but was hardly reduced at 8.8 wt%

  14. Polarographic determination of uranium dioxide stoichiometry

    International Nuclear Information System (INIS)

    Viguie, J.; Uny, G.

    1966-10-01

    The method described allows the determination of small deviations from stoichiometry for uranium dioxide. It was applied to the study of surface oxidation of bulk samples. The sample is dissolved in phosphoric acid under an argon atmosphere; U(VI) is determined by polarography in PO 4 H 3 4.5 N - H 2 SO 4 4 N. U(IV) is determined by potentiometry. The detection limit is UO 2,0002 . The accuracy for a single determination at the 95% confidence level is ±20 per cent for samples with composition included between UO 2,001 and UO 2,01 . (authors) [fr

  15. Heat transfer coefficient for boiling carbon dioxide

    DEFF Research Database (Denmark)

    Knudsen, Hans Jørgen Høgaard; Jensen, Per Henrik

    1998-01-01

    Heat transfer coefficient and pressure drop for boiling carbon dioxide (R744) flowing in a horizontal pipe has been measured. The calculated heat transfer coeeficient has been compared with the Chart correlation of Shah. The Chart Correlation predits too low heat transfer coefficient but the ratio...... between the measured and the calculated heat transfer coefficient is nearly constant and equal 1.9. With this factor the correlation predicts the measured data within 14% (RMS). The pressure drop is of the same order as the measuring uncertainty and the pressure drop has not been compared with correlation's....

  16. Carbon Dioxide Mitigation by Microalgal Photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Mijeong Lee; Gillis, James M.; Hwang, Jiann Yang [Michigan Technological University, Houghton (United States)

    2003-12-15

    Algal growth studies of Chlorella strains were conducted in a batch mode with bench type experiments. Carbon dioxide fixation rates of the following green microalgae were determined: Chlorella sp. H84, Chlorella sp. A2, Chlorella sorokiniana UTEX 1230, Chlorella vulgaris, and Chlorella pyrenoidosa. C. vulgaris, among other strains of microalgae, showed the highest growth rate (1.17 optical density/5 days). Cultivating conditions for C. vulgaris that produced the highest growth rate were at concentrations of 243 μg CO{sub 2}/mL, 10 mM ammonia, and 1 mM phosphate, with an initial pH range of 7-8.

  17. Method for Extracting and Sequestering Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Rau, Gregory H.; Caldeira, Kenneth G.

    2005-05-10

    A method and apparatus to extract and sequester carbon dioxide (CO2) from a stream or volume of gas wherein said method and apparatus hydrates CO2, and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO2 from a gaseous environment.

  18. Apparatus for extracting and sequestering carbon dioxide

    Science.gov (United States)

    Rau, Gregory H [Castro Valley, CA; Caldeira, Kenneth G [Livermore, CA

    2010-02-02

    An apparatus and method associated therewith to extract and sequester carbon dioxide (CO.sub.2) from a stream or volume of gas wherein said apparatus hydrates CO.sub.2 and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO.sub.2 from a gaseous environment.

  19. Ultrathin, epitaxial cerium dioxide on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Flege, Jan Ingo, E-mail: flege@ifp.uni-bremen.de; Kaemena, Björn; Höcker, Jan; Schmidt, Thomas; Falta, Jens [Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen (Germany); Bertram, Florian [Photon Science, Deutsches Elektronensynchrotron (DESY), Notkestraße 85, 22607 Hamburg (Germany); Wollschläger, Joachim [Department of Physics, University of Osnabrück, Barbarastraße 7, 49069 Osnabrück (Germany)

    2014-03-31

    It is shown that ultrathin, highly ordered, continuous films of cerium dioxide may be prepared on silicon following substrate prepassivation using an atomic layer of chlorine. The as-deposited, few-nanometer-thin Ce{sub 2}O{sub 3} film may very effectively be converted at room temperature to almost fully oxidized CeO{sub 2} by simple exposure to air, as demonstrated by hard X-ray photoemission spectroscopy and X-ray diffraction. This post-oxidation process essentially results in a negligible loss in film crystallinity and interface abruptness.

  20. Advanced Rechargeable Lithium Sulfur Dioxide Cell

    Science.gov (United States)

    1991-11-01

    AD-A274 908IIIIlIIIE McDonald , P. Harris, F. Goebel, S. Hossi ierra, M. Guentert, C. Todino 7 ad r nse TECHNICAL PRODUCTS INCY DTIC ELECTE JAN26 1994...Pawcatuck, CT 06379 94-02298 1425 Best Available Copy I ADVANCED RECHARGEABLE LITHIUM SULFUR DIOXIDE CELL I R.C. McDonald , P. Harris, F. Goebel, S. Hossain...20 minutes. The electrochemical measurements were carried out using a I Starbuck 20-station cycler system which is connected to a computer to monitor

  1. Nuclear energy significantly reduces carbon dioxide emissions

    International Nuclear Information System (INIS)

    Koprda, V.

    2006-01-01

    This article is devoted to nuclear energy, to its acceptability, compatibility and sustainability. Nuclear energy is non-dispensable part of energy sources with vast innovation potential. The safety of nuclear energy, radioactive waste deposition, and prevention of risk from misuse of nuclear material have to be very seriously adjudged and solved. Nuclear energy is one of the ways how to decrease the contamination of atmosphere with carbon dioxide and it solves partially also the problem of global increase of temperature and climate changes. Given are the main factors responsible for the renaissance of nuclear energy. (author)

  2. Thermal Oxidation of Structured Silicon Dioxide

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann; Hansen, Ole; Jensen, Jørgen Arendt

    2014-01-01

    The topography of thermally oxidized, structured silicon dioxide is investigated through simulations, atomic force microscopy, and a proposed analytical model. A 357 nm thick oxide is structured by removing regions of the oxide in a masked etch with either reactive ion etching or hydrofluoric acid....... Subsequent thermal oxidation is performed in both dry and wet ambients in the temperature range 950◦C to 1100◦C growing a 205 ± 12 nm thick oxide in the etched mask windows. Lifting of the original oxide near the edge of the mask in the range 6 nm to 37 nm is seen with increased lifting for increasing...

  3. The carbon dioxide capture and geological storage

    International Nuclear Information System (INIS)

    2006-06-01

    This road-map proposes by the Group Total aims to inform the public on the carbon dioxide capture and geological storage. One possible means of climate change mitigation consists of storing the CO 2 generated by the greenhouse gases emission in order to stabilize atmospheric concentrations. This sheet presents the CO 2 capture from lage fossil-fueled combustion installations, the three capture techniques and the CO 2 transport options, the geological storage of the CO 2 and Total commitments in the domain. (A.L.B.)

  4. Increased power supplied to the shelf from land

    International Nuclear Information System (INIS)

    2002-01-01

    The report analyses how increasing the power supply from land to the offshore installations will affect the emissions of carbon dioxide from the power production on land. For the time being the CO 2 emissions from the production in existing power plants outside Norway will increase. Since the power price also rises, this checks the rise in consumption. This means that the total emission of carbon dioxide does not increase as much as it would have done if the power supply to the shelf had been covered entirely by increased production in existing coal power plants. If in the long term new conventional gas power capacity can be developed commercially, then increased power supply to the shelf will cause the CO 2 emission from power production on land in Norway to increase. Should conventional gas power plants not be granted concession, then the effect will be to increase the power production in existing plants in other countries and to check the rise in consumption. The net rise in consumption increases the emission of carbon dioxide from production in coal, oil, or gas power plants in Denmark, Finland, Germany or Poland

  5. The nuclear power alternative

    International Nuclear Information System (INIS)

    Blix, H.

    1989-04-01

    The Director General of the IAEA stressed the need for energy policies and other measures which would help to slow and eventually halt the present build-up of carbon dioxide, methane and other so-called greenhouse gases, which are held to cause global warming. He urged that nuclear power and various other sources of energy, none of which contribute to global warming, should not be seen as alternatives, but should all be used to counteract the greenhouse effect. He pointed out that the commercially used renewable energies, apart from hydropower, currently represent only 0.3% of the world's energy consumption and, by contrast, the 5% of the world's energy consumption coming from nuclear power is not insignificant. Dr. Blix noted that opposition for nuclear power stems from fear of accidents and concern about the nuclear wastes. But no generation of electricity, whether by coal, hydro, gas or nuclear power, is without some risk. He emphasized that safety can never be a static concept, and that many new measures are being taken by governments and by the IAEA to further strengthen the safety of nuclear power

  6. Use of supercritical carbon dioxide extraction

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, Masayuki (Niigata Univ., Faculty of Engineering, Niigata, (Japan))

    1989-09-25

    Supercritical fluid extraction is a novel diffusion and separation technique which exploits simultaneously the increase of vapor pressure and the difference of chemical affinities of fluids near the critical point. A solvent which is used as the supercritical fluid has the following features: the critical point exists in the position of relatively ease of handling, the solvent is applicable to the extraction of a physiological active substance of thermal instability. Carbon dioxide as the solvent is non-flammable, non-corrosive, non-toxic, cheap, and readily available of high purity. The results of studies on the use of supercritical carbon dioxide (SC-CO{sub 2}) as a solvent for natural products in the fermentation and food industries, were collected. SC-CO{sub 2} extraction are used in many fields, examples for the application are as follows: removal of organic solvents from antibiotics; extraction of vegetable oils contained in wheat germ oil, high quality mustard seeds, rice bran and so on; brewing of sake using rice and rice-koji; use as a non-aqueous medium for the synthesis of precursors of the Aspartame; and use in sterilization. 66 refs., 17 figs., 21 tabs.

  7. Integrated Assessment of Carbon Dioxide Removal

    Science.gov (United States)

    Rickels, W.; Reith, F.; Keller, D.; Oschlies, A.; Quaas, M. F.

    2018-03-01

    To maintain the chance of keeping the average global temperature increase below 2°C and to limit long-term climate change, removing carbon dioxide from the atmosphere (carbon dioxide removal, CDR) is becoming increasingly necessary. We analyze optimal and cost-effective climate policies in the dynamic integrated assessment model (IAM) of climate and the economy (DICE2016R) and investigate (1) the utilization of (ocean) CDR under different climate objectives, (2) the sensitivity of policies with respect to carbon cycle feedbacks, and (3) how well carbon cycle feedbacks are captured in the carbon cycle models used in state-of-the-art IAMs. Overall, the carbon cycle model in DICE2016R shows clear improvements compared to its predecessor, DICE2013R, capturing much better long-term dynamics and also oceanic carbon outgassing due to excess oceanic storage of carbon from CDR. However, this comes at the cost of a (too) tight short-term remaining emission budget, limiting the model suitability to analyze low-emission scenarios accurately. With DICE2016R, the compliance with the 2°C goal is no longer feasible without negative emissions via CDR. Overall, the optimal amount of CDR has to take into account (1) the emission substitution effect and (2) compensation for carbon cycle feedbacks.

  8. Methanation of hydrogen and carbon dioxide

    International Nuclear Information System (INIS)

    Burkhardt, Marko; Busch, Günter

    2013-01-01

    Highlights: • The biologic methanation of exclusively gases like hydrogen and carbon dioxide is feasible. • Electrical energy can be stored in the established gas grid by conversion to methane. • The quality of produced biogas is very high (c CH4 = 98 vol%). • The conversion rate is depending on H 2 -flow rate. - Abstract: A new method for the methanation of hydrogen and carbon dioxide is presented. In a novel anaerobic trickle-bed reactor, biochemical catalyzed methanation at mesophilic temperatures and ambient pressure can be realized. The conversion of gaseous substrates by immobilized hydrogenotrophic methanogens is a unique feature of this reactor type. The already patented reactor produces biogas which has a very high quality (c CH4 = 97.9 vol%). Therefore, the storage of biogas in the existing natural gas grid is possible without extensive purification. The specific methane production was measured with P = 1.17 Nm CH4 3 /(m R 3 d). It is conceivable to realize the process at sites that generate solar or wind energy and sites subject to the conditions for hydrogen electrolysis (or other methods of hydrogen production). The combination with conventional biogas plants under hydrogen addition to methane enrichment is possible as well. The process enables the coupling of various renewable energy sources

  9. Low temperature sintering of hyperstoichiometric uranium dioxide

    International Nuclear Information System (INIS)

    Chevrel, H.

    1991-12-01

    In the lattice of uranium dioxide with hyperstoichiometric oxygen content (UO 2+x ), each additional oxygen atoms is introduced by shifting two anions from normal sites to interstitial ones, thereby creating two oxygen vacancies. The point defects then combine to form complex defects comprising several interstitials and vacancies. The group of anions (3x) in the interstitial position participate in equilibria promoting the creation of uranium vacancies thereby considerably increasing uranium self-diffusion. However, uranium grain boundaries diffusion governs densification during the first two stages of sintering of uranium dioxide with hyperstoichiometric oxygen content, i.e., up to 93% of the theoretical density. Surface diffusion and evaporation-condensation, which are considerably accentuated by the hyperstoichiometric deviation, play an active role during sintering by promoting crystalline growth during the second and third stages of sintering. U 8 O 8 can be added to adjust the stoichiometry and to form a finely porous structure and thus increase the pore area subjected to surface phenomena. The composition with an O/U ratio equal to 2.25 is found to densify the best, despite a linear growth in sintering activation energy with hyperstoichiometric oxygen content, increasing from 300 kj.mol -1 for UO 2.10 to 440 kJ.mol -1 for UO 2.25 . Seeds can be introduced to obtain original microstructures, for example the presence of large grains in small-grain matrix

  10. Design of a Uranium Dioxide Spheroidization System

    Science.gov (United States)

    Cavender, Daniel P.; Mireles, Omar R.; Frendi, Abdelkader

    2013-01-01

    The plasma spheroidization system (PSS) is the first process in the development of tungsten-uranium dioxide (W-UO2) fuel cermets. The PSS process improves particle spherocity and surface morphology for coating by chemical vapor deposition (CVD) process. Angular fully dense particles melt in an argon-hydrogen plasma jet at between 32-36 kW, and become spherical due to surface tension. Surrogate CeO2 powder was used in place of UO2 for system and process parameter development. Particles range in size from 100 - 50 microns in diameter. Student s t-test and hypothesis testing of two proportions statistical methods were applied to characterize and compare the spherocity of pre and post process powders. Particle spherocity was determined by irregularity parameter. Processed powders show great than 800% increase in the number of spherical particles over the stock powder with the mean spherocity only mildly improved. It is recommended that powders be processed two-three times in order to reach the desired spherocity, and that process parameters be optimized for a more narrow particles size range. Keywords: spherocity, spheroidization, plasma, uranium-dioxide, cermet, nuclear, propulsion

  11. Nanomaterial Case Studies: Nanoscale Titanium Dioxide in ...

    Science.gov (United States)

    EPA announced the availability of the final report, Nanomaterial Case Studies: Nanoscale Titanium Dioxide in Water Treatment and in Topical Sunscreen. This report is a starting point to determine what is known and what needs to be known about selected nanomaterials as part of a process to identify and prioritize research to inform future assessments of the potential ecological and health implications of these materials. Two specific applications of nanoscale titanium dioxide (nano-TiO2) are considered: (1) as an agent for removing arsenic from drinking water; and (2) as an active ingredient in topical sunscreen. These case studies are organized around a comprehensive environmental assessment (CEA) framework that combines a product life cycle perspective with the risk assessment paradigm. They are intended to help identify what may need to be known in order to conduct a comprehensive environmental assessment of the potential risks related to nano-TiO2. These “case studies” do not represent completed or even preliminary assessments, nor are they intended to serve as a basis for risk management decisions in the near term on these specific uses of nano TiO2. Rather, the intent is to use this document in developing the scientific and technical information needed for future assessment efforts.

  12. Molecular and physiological responses to titanium dioxide ...

    Science.gov (United States)

    - Changes in tissue transcriptomes and productivity of Arabidopsis thaliana were investigated during exposure of plants to two widely-used engineered metal oxide nanoparticles, titanium dioxide (nano-titanium) and cerium dioxide (nano-cerium). Microarray analyses confirmed that exposure to either nanoparticle altered the transcriptomes of rosette leaves and roots, with comparatively larger numbers of differentially expressed genes (DEGs) found under nano-titania exposure. Nano-titania induced more DEGs in rosette leaves, whereas roots had more DEGs under nano-ceria exposure. MapMan analyses indicated that while nano-titania up-regulated overall and secondary metabolism in both tissues, metabolic processes under nano-ceria remained mostly unchanged. Gene enrichment analysis indicated that both nanoparticles mainly enriched ontology groups such as responses to stress (abiotic and biotic), and defense responses (pathogens), and responses to endogenous stimuli (hormones). Nano-titania specifically induced genes associated with photosynthesis, whereas nano-ceria induced expression of genes related to activating transcription factors, most notably those belonging to the ethylene responsive element binding protein family. Interestingly, there were also increased numbers of rosette leaves and plant biomass under nano-ceria exposure, but not under nano-titania. Other transcriptomic responses did not clearly relate to responses observed at the organism level. This may b

  13. Adaptation to carbon dioxide tax in shipping

    International Nuclear Information System (INIS)

    Olsen, Kristian

    2000-01-01

    This note discusses the consequences for the sea transport sector between Norway and continental Europe of levying a carbon dioxide tax on international bunker. The influence of such a tax on the operational costs of various types of ship and various transport routes is calculated. The profit obtainable from the following ways of adapting to an increased tax level is assessed: (1) Reducing the speed, (2) Rebuilding the engine to decrease fuel consumption, (3) Changing the design speed for new ships. It is found that a carbon dioxide tax of NOK 200 per tonne of CO 2 will increase the transport costs by 3 - 15 percent. In the long run much of this may be transferred to the freight rates since so much of the sea transport are in segments in which the demand for the service is not sensitive to the prices. Even if the freight rates are not changed, a tax this size will not make it necessary to reduce the speed of the existing fleet. The income lost by taking fewer trips will exceed the costs saved in reducing the speed. However, the optimum design speed for new ships may be somewhat reduced (0.5 knots). Rebuilding engines to reduce the fuel consumption would pay off were it not for the fact that the remaining life of the present fleet is probably too short for this to be interesting

  14. Development of a Supercritical Carbon Dioxide Brayton Cycle: Improving VHTR Efficiency and Testing Material Compatibility - Final Report

    International Nuclear Information System (INIS)

    Chang H. Oh

    2006-01-01

    Generation IV reactors will need to be intrinsically safe, having a proliferation-resistant fuel cycle and several advantages relative to existing light water reactor (LWR). They, however, must still overcome certain technical issues and the cost barrier before it can be built in the U.S. The establishment of a nuclear power cost goal of 3.3 cents/kWh is desirable in order to compete with fossil combined-cycle, gas turbine power generation. This goal requires approximately a 30 percent reduction in power cost for state-of-the-art nuclear plants. It has been demonstrated that this large cost differential can be overcome only by technology improvements that lead to a combination of better efficiency and more compatible reactor materials. The objectives of this research are (1) to develop a supercritical carbon dioxide Brayton cycle in the secondary power conversion side that can be applied to the Very-High-Temperature Gas-Cooled Reactor (VHTR), (2) to improve the plant net efficiency by using the carbon dioxide Brayton cycle, and (3) to test material compatibility at high temperatures and pressures. The reduced volumetric flow rate of carbon dioxide due to higher density compared to helium will reduce compression work, which eventually increase plant net efficiency

  15. Market conditions for wind power and biofuel-based cogeneration

    International Nuclear Information System (INIS)

    1994-07-01

    The aim of this study is to analyze the prerequisites for biofuel-based cogeneration plants and for wind power, with special emphasis on following factors: 1/ The effect on the Swedish energy market of the opening of the power transmission networks for free competition within the electric power supply sector. 2/ A market model for the connection between the prices on fossil fuels, biomass fuels, electric power, and heating on the Swedish market. The analysis is made for three scenarios concerning carbon dioxide/energy taxation and the oil price development. The three scenarios are: A. Constant prices on heating oil and coal., B. An internationally uniform carbon dioxide tax, which successively is raised to SEK 0.40 per kilo carbon dioxide to the year 2010. In the year 2005 this will correspond to a doubling of the present prices on crude oil., C. An unilateral Swedish energy- and carbon dioxide tax of todays model (without exception for electric power generation), with constant import prices on heating oil and coal. The decisive factors for bio-cogeneration are construction- and operation costs, the costs of biofuels, and the sales price on electric power and heat. For wind power it is the construction- and operation costs that settle the conditions. 18 figs, 6 tabs

  16. [The clinical application of zirconium-dioxide-ceramics. Case report].

    Science.gov (United States)

    Somfai, Dóra; Zsigmond, Ágnes; Károlyházy, Katalin; Kispély, Barbara; Hermann, Péter

    2015-12-01

    Due to its outstanding physical, mechanical and esthetic properties, zirconium-dioxide is one of the most popular non-metal denture, capable of surpassing PFM in most cases. The recent advances of CAD/CAM technology makes it a good alternitve. Here we show the usefulness of zirconium-dioxide in everyday dental practice through three case reports.

  17. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    David A. Green; Brian S. Turk; Raghubir P. Gupta; Alejandro Lopez-Ortiz; Douglas P. Harrison; Ya Liang

    2001-07-01

    Sodium based sorbents including sodium carbonate may be used to capture carbon dioxide from flue gas. A relatively concentrated carbon dioxide stream may be recoverable for sequestration when the sorbent is regenerated. Electrobalance tests indicated that sodium carbonate monohydrate was formed in a mixture of helium and water vapor at temperatures below 65 C. Additional compounds may also form, but this could not be confirmed. In the presence of carbon dioxide and water vapor, both the initial reaction rate of sodium carbonate with carbon dioxide and water and the sorbent capacity decreased with increasing temperature, consistent with the results from the previous quarter. Increasing the carbon dioxide concentration at constant temperature and water vapor concentration produced a measurable increase in rate, as did increasing the water vapor concentration at constant carbon dioxide concentration and temperature. Runs conducted with a flatter TGA pan resulted in a higher initial reaction rate, presumably due to improved gas-solid contact, but after a short time, there was no significant difference in the rates measured with the different pans. Analyses of kinetic data suggest that the surface of the sodium carbonate particles may be much hotter than the bulk gas due to the highly exothermic reaction with carbon dioxide and water, and that the rate of heat removal from the particle may control the reaction rate. A material and energy balance was developed for a cyclic carbonation/calcination process which captures about 26 percent of the carbon dioxide present in flue gas available at 250 C.

  18. Flexible substrates as basis for photocatalytic reduction of carbon dioxide

    DEFF Research Database (Denmark)

    Jensen, Jacob; Mikkelsen, Mette; Krebs, Frederik C

    2011-01-01

    A photocatalytic system for converting carbon dioxide into carbon monoxide was designed and constructed. The system relies on thin films of the photocatalyst prepared at low temperature using spray coating. We formulated inks based on the well-known photocatalyst titanium dioxide and characterized...

  19. Carbon Dioxide and Global Warming: A Failed Experiment

    Science.gov (United States)

    Ribeiro, Carla

    2014-01-01

    Global warming is a current environmental issue that has been linked to an increase in anthropogenic carbon dioxide in the atmosphere. To raise awareness of the problem, various simple experiments have been proposed to demonstrate the effect of carbon dioxide on the planet's temperature. This article describes a similar experiment, which…

  20. Effect of high pressurized carbon dioxide on Escherichia coli ...

    African Journals Online (AJOL)

    Carbon dioxide at high pressure can retard microbial growth and sometimes kill microorganisms depending on values of applied pressure, temperature and exposure time. In this study the effect of high pressurised carbon dioxide (HPCD) on Escherichia coli was investigated. Culture of E. coli was subjected to high ...

  1. Conversion of metal plutonium to plutonium dioxide by pyrochemical method

    Energy Technology Data Exchange (ETDEWEB)

    Panov, A.V.; Subbotin, V.G. [Russian Federal Nuclear Center, ALL-Russian Science and Research Institute of Technical Physics, Snezhinsk (Russian Federation); Mashirev, V.P. [ALL-Russian Science and Research Institute of Chemical Technology, Moscow (Russian Federation)

    2000-07-01

    Report contains experimental results on metal plutonium of weapon origin samples conversion to plutonium dioxide by pyrochemical method. Circuits of processes are described. Their advantages and shortcomings are shown. Parameters of plutonium dioxide powders (phase and fraction compositions, poured density) manufactured by pyrochemical method in RFNC-VNIITF are shown as well. (authors)

  2. Classification of titanium dioxide; Clasificacion del dioxido de titanio

    Energy Technology Data Exchange (ETDEWEB)

    Macias B, L.R. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Garcia C, R.M.; Maya M, M.E. [Secretaria de Hacienda y Credito Publico de Mexico, Mexico (Mexico); Ita T, A. De [Universidad Autonoma Metropolitana Azcapotzalco, Mexico (Mexico); Palacios G, J. [Instituto Politecnico Nacional (Mexico)

    2002-07-01

    In this work the X-ray diffraction (XRD), Scanning Electron Microscopy (Sem) and the X-ray Dispersive Energy Spectroscopy techniques are used with the purpose to achieve a complete identification of phases and mixture of phases of a crystalline material as titanium dioxide. The problem for solving consists of being able to distinguish a sample of titanium dioxide being different than a titanium dioxide pigment. A standard sample of titanium dioxide with NIST certificate is used, which indicates a purity of 99.74% for the TiO{sub 2}. The following way is recommended to proceed: a)To make an analysis by means of X-ray diffraction technique to the sample of titanium dioxide pigment and on the standard of titanium dioxide waiting not find differences. b) To make a chemical analysis by the X-ray Dispersive Energy Spectroscopy via in a microscope, taking advantage of the high vacuum since it is oxygen which is analysed and if it is concluded that the aluminium oxide appears in a greater proportion to 1% it is established that is a titanium dioxide pigment, but if it is lesser then it will be only titanium dioxide. This type of analysis is an application of the nuclear techniques useful for the tariff classification of merchandise which is considered as of difficult recognition. (Author)

  3. Model studies of limitation of carbon dioxide emissions reduction

    International Nuclear Information System (INIS)

    1992-01-01

    The report consists of two papers concerning mitigation of CO 2 emissions in Sweden, ''Limitation of carbon dioxide emissions. Socio-economic effects and the importance of international coordination'', and ''Model calculations for Sweden's energy system with carbon dioxide limitations''. Separate abstracts were prepared for both of the papers

  4. Balance and forecasts of french carbon dioxide emissions

    International Nuclear Information System (INIS)

    1992-11-01

    This paper strikes the balance of carbon dioxide emissions in France between 1986 and 1991 and gives forecasts till 2010. Since 1986, France has reduced its efforts for energy conservation and air pollution by carbon dioxide begins to growth again in connection with consumption growth in transport area, development of computer and simulation needs

  5. 40 CFR 52.1676 - Control strategy: Nitrogen dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. 52.1676 Section 52.1676 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR 16347...

  6. 40 CFR 52.1576 - Control strategy: Nitrogen dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. 52.1576 Section 52.1576 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... strategy: Nitrogen dioxide. (a) The requirements of § 52.14(c)(3) of this chapter as of May 8, 1974 (39 FR...

  7. 40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. 52.1876 Section 52.1876 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan...

  8. Fixation of carbon dioxide into dimethyl carbonate over ...

    Science.gov (United States)

    A titanium-based zeolitic thiophene-benzimidazolate framework has been designed for the direct synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide. The developed catalyst activates carbon dioxide and delivers over 16% yield of DMC without the use of any dehydrating agent or requirement for azeotropic distillation. Prepared for submission to Nature Scientific reports.

  9. Method for synthesis of titanium dioxide nanotubes using ionic liquids

    Science.gov (United States)

    Qu, Jun; Luo, Huimin; Dai, Sheng

    2013-11-19

    The invention is directed to a method for producing titanium dioxide nanotubes, the method comprising anodizing titanium metal in contact with an electrolytic medium containing an ionic liquid. The invention is also directed to the resulting titanium dioxide nanotubes, as well as devices incorporating the nanotubes, such as photovoltaic devices, hydrogen generation devices, and hydrogen detection devices.

  10. The future of nuclear power

    International Nuclear Information System (INIS)

    Corak, Z.

    2004-01-01

    Energy production and use will contribute to global warming through greenhouse gas emissions in the next 50 years. Although nuclear power is faced with a lot of problems to be accepted by the public, it is still a significant option for the world to meet future needs without emitting carbon dioxide (CO 2 ) and other atmospheric pollutants. In 2002, nuclear power provided approximately 17% of world energy consumption. There is belief that worldwide electricity consumption will increase in the next few years, especially in the developing countries followed by economic growth and social progress. Official forecasts shows that there will be a mere increase of 5% in nuclear electricity worldwide by 2020. There are also predictions that electricity use may increase at 75%. These predictions require a necessity for construction of new nuclear power plants. There are only a few realistic options for reducing carbon dioxide emissions from electricity generation: Increase efficiency in electricity generation and use; Expand use of renewable energy sources such as wind, solar, biomass and geothermal; Capture carbon dioxide emissions at fossil-fuelled electric generating plants and permanently sequester the carbon; Increase use of nuclear power. In spite of the advantages that nuclear power has, it is faced with stagnation and decline today. Nuclear power is faced with four critical problems that must be successfully defeat for the large expansion of nuclear power to succeed. Those problems are cost, safety, waste and proliferation. Disapproval of nuclear power is strengthened by accidents that occurred at Three Mile Island in 1979, at Chernobyl in 1986 and by accidents at fuel cycle facilities in Japan, Russia and in the United States of America. There is also great concern about the safety and security of transportation of nuclear materials and the security of nuclear facilities from terrorist attack. The paper will provide summarized review regarding cost, safety, waste and

  11. Combined microcalorimetric and IR spectroscopic study on carbon dioxide adsorption in H-MCM-22

    Energy Technology Data Exchange (ETDEWEB)

    Arean, C.O., E-mail: co.arean@uib.es [Department of Chemistry, University of the Balearic Islands, 07122 Palma de Mallorca (Spain); Delgado, M.R. [Department of Chemistry, University of the Balearic Islands, 07122 Palma de Mallorca (Spain); Bulánek, R.; Frolich, K. [Department of Physical Chemistry, Faculty of Chemical Technology, University of Pardubice, 532 10 Pardubice (Czech Republic)

    2014-10-15

    Highlights: • Adsorption calorimetry and variable temperature IR spectroscopy is used to study adsorption of CO{sub 2} in the protonic zeolite H-MCM-22. • By simultaneously recording IR absorbance over a temperature range, temperature and equilibrium pressure, standard adsorption enthalpy and entropy of CO{sub 2} was determined. • The results are discussed in the broader context of carbon dioxide capture from the flue gas of fossil fuel fired power stations. - Abstract: The thermodynamics of carbon dioxide adsorption in the protonic zeolite H-MCM-22 (Si:Al = 16:1) was investigated by means of adsorption calorimetry and variable-temperature IR spectroscopy, a technique that affords determination of standard adsorption enthalpy (ΔH{sup 0}) and entropy (ΔS{sup 0}) from analysis of a series of IR spectra recorded over a temperature range while simultaneously measuring equilibrium pressure inside a closed IR cell. ΔH{sup 0} resulted to be −24.5 (±2) kJ mol{sup −1}, while for the entropy change the value of ΔS{sup 0} = −115 (±10) J mol{sup −1} K{sup −1} was obtained. The obtained ΔH{sup 0} value is compared with those reported in the literature for the adsorption of CO{sub 2} on other zeolites, and discussed in the context of carbon dioxide capture and sequestration.

  12. High-resolution measurements from the airborne Atmospheric Nitrogen Dioxide Imager (ANDI)

    Science.gov (United States)

    Lawrence, J. P.; Anand, J. S.; Vande Hey, J. D.; White, J.; Leigh, R. R.; Monks, P. S.; Leigh, R. J.

    2015-11-01

    Nitrogen dioxide is both a primary pollutant with direct health effects and a key precursor of the secondary pollutant ozone. This paper reports on the development, characterisation and test flight of the Atmospheric Nitrogen Dioxide Imager (ANDI) remote sensing system. The ANDI system includes an imaging UV/Vis grating spectrometer able to capture scattered sunlight spectra for the determination of tropospheric nitrogen dioxide (NO2) concentrations by way of DOAS slant column density and vertical column density measurements. Results are shown for an ANDI test flight over Leicester City in the UK on a cloud-free winter day in February 2013. Retrieved NO2 columns gridded to a surface resolution of 80 m × 20 m revealed hotspots in a series of locations around Leicester City, including road junctions, the train station, major car parks, areas of heavy industry, a nearby airport (East Midlands) and a power station (Ratcliffe-on-Soar). In the city centre the dominant source of NO2 emissions was identified as road traffic, contributing to a background concentration as well as producing localised hotspots. Quantitative analysis revealed a significant urban increment over the city centre which increased throughout the flight.

  13. Capacitance-Assisted Sustainable Electrochemical Carbon Dioxide Mineralisation.

    Science.gov (United States)

    Lamb, Katie J; Dowsett, Mark R; Chatzipanagis, Konstantinos; Scullion, Zhan Wei; Kröger, Roland; Lee, James D; Aguiar, Pedro M; North, Michael; Parkin, Alison

    2018-01-10

    An electrochemical cell comprising a novel dual-component graphite and Earth-crust abundant metal anode, a hydrogen producing cathode and an aqueous sodium chloride electrolyte was constructed and used for carbon dioxide mineralisation. Under an atmosphere of 5 % carbon dioxide in nitrogen, the cell exhibited both capacitive and oxidative electrochemistry at the anode. The graphite acted as a supercapacitive reagent concentrator, pumping carbon dioxide into aqueous solution as hydrogen carbonate. Simultaneous oxidation of the anodic metal generated cations, which reacted with the hydrogen carbonate to give mineralised carbon dioxide. Whilst conventional electrochemical carbon dioxide reduction requires hydrogen, this cell generates hydrogen at the cathode. Carbon capture can be achieved in a highly sustainable manner using scrap metal within the anode, seawater as the electrolyte, an industrially relevant gas stream and a solar panel as an effective zero-carbon energy source. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  14. Adverse effects of the automotive industry on carbon dioxide emissions

    Directory of Open Access Journals (Sweden)

    Mpho Bosupeng

    2016-05-01

    Full Text Available This study aims to determine the effects of the automotive industry on carbon dioxide emissions for the period from 1997 to 2010 for diverse economies, as well as the relationships between carbon dioxide discharges and output. The study applies cointegration and causality tests to validate these associations. The results of the Johansen cointegration test depict long-run associations between the quantity of passenger cars and carbon dioxide emissions in France, Sweden, Spain, Hungary and Japan. In addition, significant relations were observed between output and carbon dioxide discharges in Spain, Canada, India and Japan. Changes in output had substantial impact on emissions in Germany, Canada and India. The results also show that the number of passenger cars influences the magnitude of emissions in multiple economies. In conclusion, the automotive industry has to be considered in policies that aim to reduce carbon dioxide emissions.

  15. Carbon dioxide for enhanced oil recovery in Canada

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, S.; Manbybura, F.; Sparks, N.

    1985-01-01

    This paper examines the potential for carbon dioxide as a major miscible solvent in Canada and describes Shell Canada's carbon dioxide exploration efforts over the last few years. Enhanced oil recovery, specifically miscible flooding, has been recognized as a technically and economically feasible method for adding reserves and productive capacity to Canada's light and medium oil. The fiscal regime has been altered by both the federal and provincial governments to encourage miscible flooding development. As a result many projects have been initiated with others being evaluated and designed. This paper analyzes the history and the direction of miscible flooding in the United States, where carbon dioxide is becoming the predominant miscible solvent. The potential for future use of carbon dioxide in Canada is specifically addressed: potential oil recovery solvent supply, and economics. Shell's carbon dioxide exploration play currently underway is also discussed.

  16. Carbon dioxide from fossil fuels: adapting to uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Chen, K; Winter, R C; Bergman, M K

    1980-12-01

    If present scientific information is reasonable, the world is likely to experience noticeable global warming by the beginning of the next century if high annual growth rates of fossil-fuel energy use continue. Only with optimistic assumptions and low growth rates will carbon-dioxide-induced temperature increases be held below 2/sup 0/C or so over the next century. Conservation, flexible energy choices, and control options could lessen the potential effects of carbon dioxide. Though perhaps impractical from the standpoint of costs and efficiency losses, large coastal centralized facilities would be the most amenable to carbon dioxide control and disposal. Yet no country can control carbon dioxide levels unilaterally. The USA, however, which currently contributes over a quarter of all fossil-fuel carbon dioxide emissions and possesses a quarter of the world's coal resources, could provide a much needed role in leadership, research and education. 70 references.

  17. Carbon dioxide stripping in aquaculture. part 1: terminology and reporting

    Science.gov (United States)

    Colt, John; Watten, Barnaby; Pfeiffer, Tim

    2012-01-01

    The removal of carbon dioxide gas in aquacultural systems is much more complex than for oxygen or nitrogen gas because of liquid reactions of carbon dioxide and their kinetics. Almost all published carbon dioxide removal information for aquaculture is based on the apparent removal value after the CO2(aq) + HOH ⇔ H2CO3 reaction has reached equilibrium. The true carbon dioxide removal is larger than the apparent value, especially for high alkalinities and seawater. For low alkalinity freshwaters (<2000 μeq/kg), the difference between the true and apparent removal is small and can be ignored for many applications. Analytical and reporting standards are recommended to improve our understanding of carbon dioxide removal.

  18. Carbon Dioxide Detection and Indoor Air Quality Control.

    Science.gov (United States)

    Bonino, Steve

    2016-04-01

    When building ventilation is reduced, energy is saved because it is not necessary to heat or cool as much outside air. Reduced ventilation can result in higher levels of carbon dioxide, which may cause building occupants to experience symptoms. Heating or cooling for ventilation air can be enhanced by a DCV system, which can save energy while providing a comfortable environment. Carbon dioxide concentrations within a building are often used to indicate whether adequate fresh air is being supplied to the building. These DCV systems use carbon dioxide sensors in each space or in the return air and adjust the ventilation based on carbon dioxide concentration; the higher the concentration, the more people occupy the space relative to the ventilation rate. With a carbon dioxide sensor DCV system, the fresh air ventilation rate varies based on the number ofpeople in the space, saving energy while maintaining a safe and comfortable environment.

  19. Difficult colonoscopy: air, carbon dioxide, or water insufflation?

    Science.gov (United States)

    Chaubal, Alisha; Pandey, Vikas; Patel, Ruchir; Poddar, Prateik; Phadke, Aniruddha; Ingle, Meghraj; Sawant, Prabha

    2018-04-01

    This study aimed to compare tolerance to air, carbon dioxide, or water insufflation in patients with anticipated difficult colonoscopy (young, thin, obese individuals, and patients with prior abdominal surgery or irradiation). Patients with body mass index (BMI) less than 18 kg/m 2 or more than 30 kg/m 2 , or who had undergone previous abdominal or pelvic surgeries were randomized to air, carbon dioxide, or water insufflation during colonoscopy. The primary endpoint was cecal intubation with mild pain (less than 5 on visual analogue scale [VAS]), without use of sedation. The primary end point was achieved in 32.7%, 43.8%, and 84.9% of cases with air, carbon dioxide and water insufflation ( P carbon dioxide, and water insufflation ( P carbon dioxide for pain tolerance. This was seen in the subgroups with BMI 30 kg/m 2 .

  20. New technology for carbon dioxide at high pressure

    International Nuclear Information System (INIS)

    Hassina, Bazaze; Raouf, Zehioua; Menial, A. H.

    2006-01-01

    Carbon dioxide has long been the nemesis of environmentalists because of its role in global warming, but under just the right conditions-namely, high pressure and high temperature its one of nature's best and most environmentally benign solvents. Decaf-coffee lovers, for instance, benefit from its ability to remove caffeine from coffee beans.During the last few years, carbon dioxide has also made inroads in the dry-cleaning industry, providing a safe cleaning alternative to the chemical perchloroethylene. But it's on the high-tech front that carbon dioxide may make its biggest impact. T here are huge opportunities. Scientists have known for more than a century that at 75 times atmospheric pressure and 31 degree centigrade, carbon dioxide goes into and odd state that chemists called s upercritical . What's interesting to industry is that supercritical carbon dioxide may be an enabling technology for going to smaller dimensions.(Author)

  1. Carbon dioxide sequestration in oil sands tailings streams

    Energy Technology Data Exchange (ETDEWEB)

    Mikula, R.; Afara, M.; Namsechi, B.; Demko, B.; Wong, P. [Natural Resources Canada, Devon, AB (Canada). CANMET Western Research Centre

    2010-07-01

    This PowerPoint presentation discussed the use of carbon dioxide (CO{sub 2}) as an oil sands tailings process aid and investigated its role in maximizing recycle water availability by rapid consolidation of the transition zone. The potential for CO{sub 2} sequestration was also investigated. CO{sub 2} composite tailings (CT) pilot plants were discussed and the results of cylinder tests and water chemistry analyses were presented. Issues related to physical entrapment, ionic trapping, and mineral trapping were discussed. The study showed that carbonic acid lowers pH, dissolving calcite and dolomite. Aluminum hydroxide groups on the clay surface reacted to produce water and Al{sup 3+} and Na+. Increased bicarbonate and calcium resulted in precipitated calcite. The reduction of a transition zone from 6 to 3 meters increased the available recycle water by 15 mm{sup 3} in a 5 km{sup 2} recycle water pond. Optimum CO{sub 2} additions to whole tailings are now being investigated. tabs., figs.

  2. Computational Fluid Dynamics Analysis of Supercritical Carbon Dioxide Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae W.; Kim, Nam H.; Suh, Kune Y. [Seoul National University, Seoul (Korea, Republic of); Kim, Seung O. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2006-07-01

    The supercritical carbon dioxide (SCO{sub 2}) gas turbine Brayton cycle has been not only adopted in the secondary loop of the Generation IV nuclear energy systems but also planned to be installed in the high efficiency power conversion cycles of the nuclear fusion reactors. The potential beneficiaries include the Korea Advanced Liquid Metal Reactor (KALIMER), Korea Superconducting Tokamak Advanced Research (KSTAR) and International Thermonuclear Experimental Reactor (ITER). The reason for these welcomed applications is that the cycle can achieve the overall energy conversion efficiency as high as 45%. The SCO{sub 2} turbine efficiency is one of the major parameters affecting the overall Brayton cycle efficiency. Thus, optimal turbine design determines the economics of the Generation IV as well as the future nuclear fission and fusion energy industry. Seoul National University has recently been working on the SCO{sub 2} based Modular Optimized Brayton Integral System (MOBIS). MOBIS includes the Gas Advanced Turbine Operation Study (GATOS), the Loop Operating Brayton Optimization Study (LOBOS), the Nonsteady Operation Multidimensional Online Simulator (NOMOS), and the Turbine Advanced Compressor Operation Study (TACOS). This paper presents first results from GATOS.

  3. Computational Fluid Dynamics Analysis of Supercritical Carbon Dioxide Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae W.; Kim, Nam H.; Suh, Kune Y. [Seoul National University, Seoul (Korea, Republic of); Kim, Seung O. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2007-07-01

    The supercritical carbon dioxide (SCO{sub 2}) gas turbine Brayton cycle has been not only adopted in the secondary loop of the Generation IV nuclear energy systems but also planned to be installed in the high efficiency power conversion cycles of the nuclear fusion reactors. The potential beneficiaries include the Korea Advanced Liquid Metal Reactor (KALIMER), the Korea Superconducting Tokamak Advanced Research (KSTAR) as well as the International Thermonuclear Experimental Reactor (ITER). The reason for these welcomed applications is that the cycle can achieve the overall energy conversion efficiency as high as 45%. The SCO{sub 2} turbine efficiency is one of the major parameters affecting the overall Brayton cycle efficiency. Thus, optimal turbine design determines the economics of the Generation IV as well as the future nuclear fission and fusion energy industry. Seoul National University has recently been working on the SCO{sub 2} based Modular Optimized Brayton Integral System (MOBIS). MOBIS includes the Gas Advanced Turbine Operation Study (GATOS), the Loop Operating Brayton Optimization Study (LOBOS), the Nonsteady Operation Multidimensional Online Simulator (NOMOS), and the Turbine Advanced Compressor Operation Study (TACOS). This paper presents results from GATOS.

  4. Digital Printing of Titanium Dioxide for Dye Sensitized Solar Cells.

    Science.gov (United States)

    Cherrington, Ruth; Wood, Benjamin Michael; Salaoru, Iulia; Goodship, Vannessa

    2016-05-04

    Silicon solar cell manufacturing is an expensive and high energy consuming process. In contrast, dye sensitized solar cell production is less environmentally damaging with lower processing temperatures presenting a viable and low cost alternative to conventional production. This paper further enhances these environmental credentials by evaluating the digital printing and therefore additive production route for these cells. This is achieved here by investigating the formation and performance of a metal oxide photoelectrode using nanoparticle sized titanium dioxide. An ink-jettable material was formulated, characterized and printed with a piezoelectric inkjet head to produce a 2.6 µm thick layer. The resultant printed layer was fabricated into a functioning cell with an active area of 0.25 cm(2) and a power conversion efficiency of 3.5%. The binder-free formulation resulted in a reduced processing temperature of 250 °C, compatible with flexible polyamide substrates which are stable up to temperatures of 350 ˚C. The authors are continuing to develop this process route by investigating inkjet printing of other layers within dye sensitized solar cells.

  5. Carbon dioxide dissociation and buffering in chicken blood during development.

    Science.gov (United States)

    Tazawa, H; Piiper, J

    1984-07-01

    Carbon dioxide dissociation curves of oxygenated and deoxygenated bloods, the Haldane effect, the buffer value and other blood and true plasma buffering indices, O2 capacity and hematocrit were determined in bloods withdrawn from chicks before, during and after hatching and 8-month-old hens. Blood CO2 dissociation curves shifted upwards in the developing embryo till pipping, and moved downwards after pipping and hatching. In accordance with the position of the CO2 dissociation curves, the true plasma bicarbonate and red cell CO2 standardized to PCO2 = 40 torr changed. The Haldane factor at standard PCO2 increased from 0.12-0.13 on days 10-14 of incubation to 0.34 in young hens. The buffering power changed in parallel with O2 capacity and hematocrit, increasing steadily during incubation, dropping at hatching and then increasing again to the adult value. The observed changes in the CO2 dissociation curves and buffering variables during the development enable the chick to minimize the changes in the acid-base status and are favorable for coping with the increasing demand for CO2 transport and buffering of the developing bird.

  6. Computational Fluid Dynamics Analysis of Supercritical Carbon Dioxide Turbine

    International Nuclear Information System (INIS)

    Kim, Tae W.; Kim, Nam H.; Suh, Kune Y.; Kim, Seung O.

    2006-01-01

    The supercritical carbon dioxide (SCO 2 ) gas turbine Brayton cycle has been not only adopted in the secondary loop of the Generation IV nuclear energy systems but also planned to be installed in the high efficiency power conversion cycles of the nuclear fusion reactors. The potential beneficiaries include the Korea Advanced Liquid Metal Reactor (KALIMER), Korea Superconducting Tokamak Advanced Research (KSTAR) and International Thermonuclear Experimental Reactor (ITER). The reason for these welcomed applications is that the cycle can achieve the overall energy conversion efficiency as high as 45%. The SCO 2 turbine efficiency is one of the major parameters affecting the overall Brayton cycle efficiency. Thus, optimal turbine design determines the economics of the Generation IV as well as the future nuclear fission and fusion energy industry. Seoul National University has recently been working on the SCO 2 based Modular Optimized Brayton Integral System (MOBIS). MOBIS includes the Gas Advanced Turbine Operation Study (GATOS), the Loop Operating Brayton Optimization Study (LOBOS), the Nonsteady Operation Multidimensional Online Simulator (NOMOS), and the Turbine Advanced Compressor Operation Study (TACOS). This paper presents first results from GATOS

  7. Bioreactors for fixation and effective utilization of carbon dioxide gas. Tansan gas no koteiter dot yuko riyo no tame no bio reactor

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, K. (Osaka University, Osaka (Japan). Faculty of Pharmaceutical Science); Benemann, J. (California University, CA (USA))

    1991-06-01

    As for a preventive countermeasure against the global warming, experiments and studies have been conducted on the bioreactors to fix carbon dioxide gas recovered from the concentric and large scale generating sources such as thermal power plamts in a form of carbohydrate by means of the culture of microbial algae. By using the Vertical Tube Reactors (VTR) culturing apparatus, a variety of microbial algae were cultivated and experiments were performed on the relationship of biomass productivity and absorption rate of carbon dioxide gas indoors and outdoors. Consequently, it was found that when the flow rate of carbon dioxide gas is adjusted to make the biomass productivity of filament type Nostoc maximum,the inlet and outlet concentrations of carbon dioxide gas were 0.7% and 0.05% respectively with the absorption rate of more than 90%. From the standpoint of fixation and effective utilization of carbon dioxide gas, the above rate of removal is one of the important parameters and it will be necessary in future to compare the rates of removal of carbon dioxide gas among various types of bioreactors as a function of operating condition. 9 refs., 6 figs., 2 tabs.

  8. Indoor concentrations of nitrogen dioxide and sulfur dioxide from burning solid fuels for cooking and heating in Yunnan Province, China

    NARCIS (Netherlands)

    Seow, Wei Jie; Downward, George S; Wei, Hu; Rothman, Nathaniel; Reiss, Boris; Xu, Jun; Bassig, Bryan A; Li, Jihua; He, Jun; Hosgood, H Dean; Wu, Guoping; Chapman, Robert S; Tian, Linwei; Wei, Fusheng; Caporaso, Neil E; Vermeulen, Roel; Lan, Qing

    2016-01-01

    The Chinese national pollution census has indicated that the domestic burning of solid fuels is an important contributor to nitrogen dioxide (NO2 ) and sulfur dioxide (SO2 ) emissions in China. To characterize indoor NO2 and SO2 air concentrations in relation to solid fuel use and stove ventilation

  9. Dissolution of uranium dioxide in supercritical carbon dioxide modified with tri-n-butyl phosphate-hydrogen peroxide

    International Nuclear Information System (INIS)

    Kanekar, A.S.; Pathak, P.N.; Mohapatra, P.K.; Manchanda, V.K.

    2009-01-01

    Direct dissolution of uranium dioxide in supercritical carbon dioxide modified with tri-n-butyl phosphate (TBP) has been attempted. The effects of TBP concentration and pressure on the extraction of uranium have been studied. Addition of hydrogen peroxide in the modifier enhances the dissolution/extraction of uranium. (author)

  10. Photobiological hydrogen production and carbon dioxide sequestration

    Science.gov (United States)

    Berberoglu, Halil

    Photobiological hydrogen production is an alternative to thermochemical and electrolytic technologies with the advantage of carbon dioxide sequestration. However, it suffers from low solar to hydrogen energy conversion efficiency due to limited light transfer, mass transfer, and nutrient medium composition. The present study aims at addressing these limitations and can be divided in three parts: (1) experimental measurements of the radiation characteristics of hydrogen producing and carbon dioxide consuming microorganisms, (2) solar radiation transfer modeling and simulation in photobioreactors, and (3) parametric experiments of photobiological hydrogen production and carbon dioxide sequestration. First, solar radiation transfer in photobioreactors containing microorganisms and bubbles was modeled using the radiative transport equation (RTE) and solved using the modified method of characteristics. The study concluded that Beer-Lambert's law gives inaccurate results and anisotropic scattering must be accounted for to predict the local irradiance inside a photobioreactor. The need for accurate measurement of the complete set of radiation characteristics of microorganisms was established. Then, experimental setup and analysis methods for measuring the complete set of radiation characteristics of microorganisms have been developed and successfully validated experimentally. A database of the radiation characteristics of representative microorganisms have been created including the cyanobacteria Anabaena variabilis, the purple non-sulfur bacteria Rhodobacter sphaeroides and the green algae Chlamydomonas reinhardtii along with its three genetically engineered strains. This enabled, for the first time, quantitative assessment of the effect of genetic engineering on the radiation characteristics of microorganisms. In addition, a parametric experimental study has been performed to model the growth, CO2 consumption, and H 2 production of Anabaena variabilis as functions of

  11. Ultrafast measurements of chlorine dioxide photochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Ludowise, P.D.

    1997-08-01

    Time-resolved mass spectrometry and time-resolved photoelectron spectroscopy are used to study the ultrafast photodissociation dynamics of chlorine dioxide, an important constituent in stratospheric ozone depletion. Chapter 1 introduces these pump/probe techniques, in which a femtosecond pump pulse excites a molecule to a dissociative state. At a later time, a second femtosecond probe pulse ionizes the molecule. The resulting mass and photoelectron spectra are acquired as a function of the delay between the pump and probe pulses, which follows the evolution of the molecule on the excited state. A comparison to other techniques used to study reaction dynamics is discussed. Chapter 2 includes a detailed description of the design and construction of the experimental apparatus, which consists of a femtosecond laser system, a molecular beam time-of-flight spectrometer, and a data acquisition system. The time-of-flight spectrometer is specifically designed to have a short flight distance to maximize the photoelectron collection efficiency without degrading the resolution, which is limited by the bandwidth of the femtosecond laser system. Typical performance of the apparatus is demonstrated in a study of the time-resolved photoelectron spectroscopy of nitric oxide. The results of the time-resolved mass spectrometry experiments of chlorine dioxide are presented in Chapter 3. Upon excitation to the A {sup 2}A{sub 2} state near 3.2 eV, the molecule dissociates through an indirect two-step mechanism. The direct dissociation channel has been predicted to be open, but is not observed. A quantum beat is observed in the OClO{sup +} species, which is described as a vibrational coherence of the optically prepared A {sup 2}A{sub 2} state. Chapter 4 presents the results of the time-resolved photoelectron experiments of chlorine dioxide. At short delay time, the quantum beat of the OClO{sup +} species is observed in the X {sup 1}A{sub 1} state of the ion. At infinite delay, the signal

  12. Atomic Power

    African Journals Online (AJOL)

    carbon can also exist as 6Cl J, i.e. a heavier species, because its mass .... mium or boron, which have the property of absorb- ing neutrons ... When a reactor plant is in operation, it is neces- ... are replaced by uranium dioxide, the higher gas.

  13. Design of a supercritical carbon dioxide cooled reactor for marine applications

    International Nuclear Information System (INIS)

    Bollardiere, T. Paris de; Verchere, T.; Wilson, M.; O'Sullivan, P.; Heap, S.; Thompson, A.; Jewer, S.; Beeley, P.A.

    2009-01-01

    The reactor physics and thermal hydraulics aspects of a feasibility study conducted to assess the potential of a supercritical carbon dioxide (sCO2) cooled nuclear reactor for marine propulsion are presented. Supercritical carbon dioxide cycles have been proposed for next generation nuclear plants as such cycles take advantage of sCO2 property changes near the critical point which leads to improved plant efficiency over existing nuclear plant cycles at the same temperatures and pressures. Selecting two 192 MWth cores and a recompression Brayton cycle it was determined that a maximum power conversion efficiency of 47.5 % could be achieved. The core design employs TRISO particles in a graphite matrix forming a fuelled annulus in a prismatic graphite moderating block. The design of this plant has been modeled using WIMS/MONK (neutronics) and Flownex (plant thermal hydraulics and power conversion). Plant modeling found that the core remains within thermal safety limits in the event of a LOCA. The major limitation of the design was found to be the high xenon levels produced as a result of the high neutron flux required of a gas cooled reactor and the effect it has on the versatility of the plant to cope with changes in power demand. (author)

  14. Impact of silica dioxide nanoparticles on the morphology of internal organs in rats by oral supplementation

    Directory of Open Access Journals (Sweden)

    N.V. Zaitseva

    2016-12-01

    Full Text Available The object of the study was amorphous silica dioxide (SiO 2 , which is widely used as a food additive (E551, a subsidiary component in pharmaceutical preparations, perfumery and cosmetic products etc. In the specification of JECFA silica dioxide does not have information about the size of its particles, which allows the use of fine amorphous SiO 2 , obtained by gas phase hydrolysis of tetrachlorosilane as a food additive. This material, known as the "Aerosil", is characterized by the size of the specific surface area of 300–380 m 2 /g and the size of its relatively weakly agglomerated particles of 6–30 nm, i.e., it is a nanomaterial. In the biological model the morphological changes in organs and tissue systems on oral supplementation of nanoscale particles of silica dioxide were studied. Wistar male rats were given nanosized silica dioxide with specific surface area of 300 m 2 /g and primary nanoparticle size on the basis of data of electrical, atomic-powered microscopy, and dynamic light scattering in the range of 20–60 nm during 92 days. Light microscopic morphological examination of organs of rats showed a relatively mild inflammation in the structure of parenchymal organs (liver, kidney, not showing a certain dose-dependent nanoparticles. The most pronounced changes were in ileum morphology, consisting of a massive lymph macrophage and eosinophil infiltration of villi, without any apparent violation of their epithelial layer structure, which indirectly indicates the absence of violations of the barrier function of the intestinal epithelium. At the maximum dose of 100 mg/kg bw, the increased immune response was the most significant in the wall of the ileum. The results indicate the potential risks to human health when using SiO 2 having a specific surface area of 300 m 2 /g or higher in the composition of food products as a food additive.

  15. EVALUATION OF CARBON DIOXIDE CAPTURE FROM EXISTING COAL FIRED PLANTS BY HYBRID SORPTION USING SOLID SORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    Benson, Steven; Browers, Bruce; Srinivasachar, Srivats; Laudal, Daniel

    2014-12-31

    Under contract DE-FE0007603, the University of North Dakota conducted the project Evaluation of Carbon Dioxide Capture from Existing Coal Fired Plants by Hybrid Sorption Using Solid Sorbents. As an important element of this effort, a Technical and Economic Feasibility Study was conducted by Barr Engineering Co. (Barr) in association with the University of North Dakota. The assessment developed a process flow diagram, major equipment list, heat balances for the SCPC power plant, capital cost estimate, operating cost estimate, levelized cost of electricity, cost of CO2 capture ($/ton) and three sensitivity cases for the CACHYS™ process.

  16. Welding uranium with a multikilowatt, continuous-wave, carbon dioxide laser welder

    International Nuclear Information System (INIS)

    Turner, P.W.; Townsend, A.B.

    1977-01-01

    A 15-kilowatt, continuous-wave carbon dioxide laser was contracted to make partial-penetration welds in 6.35-and 12.7-mm-thick wrought depleted uranium plates. Welding power and speed ranged from 2.3 to 12.9 kilowatts and from 21 to 127 millimeters per second, respectively. Results show that depth-to-width ratios of at least unity are feasible. The overall characteristics of the process indicate it can produce welds resembling those made by the electron-beam welding process

  17. Monitoring of sulfur dioxide emission resulting from biogas utilization on commercial pig farms in Taiwan.

    Science.gov (United States)

    Su, Jung-Jeng; Chen, Yen-Jung

    2015-01-01

    The objective of this work tends to promote methane content in biogas and evaluate sulfur dioxide emission from direct biogas combustion without desulfurization. Analytical results of biogas combustion showed that combustion of un-desulfurized biogas exhausted more than 92% of SO₂ (P hydrogen sulfide was removed during the combustion process using un-desulfurized biogas (P hydrogen sulfide may deposit on the surfaces of power generator's engines or burner heads of boilers. Some of them (4.6-9.1% of H₂S) were converted to SO₂ in exhaust gas. Considering the impacts to human health and living environment, it is better to desulfurize biogas before any applications.

  18. Supercritical Fluid Extraction (SFE) of uranium and thorium nitrates using carbon dioxide modified with phosphonates

    International Nuclear Information System (INIS)

    Pitchaiah, K.C.; Sujatha, K.; Brahmananda Rao, C.V.S.; Sivaraman, N.; Vasudeva Rao, P.R.

    2014-01-01

    Supercritical Fluid Extraction (SFE) has emerged as a powerful technique for the extraction of metal ions.The liquid like densities and gas like physical properties of supercritical fluids make them unique to act as special solvents. SFE based procedures were developed and demonstrated in our laboratory for the recovery of actinides from various matrices. In the present study, we have examined for the first time, the use of dialkylalkylphosphonates in supercritical carbon dioxide (Sc-CO 2 ) medium to study the extraction behavior of uranium and thorium nitrates. A series of phosphonates were synthesised by Michaelis-Becker reaction in our laboratory and employed for the SFE

  19. Micromechanical simulation of Uranium dioxide polycrystalline aggregate behaviour under irradiation

    International Nuclear Information System (INIS)

    Pacull, J.

    2011-02-01

    In pressurized water nuclear power reactor (PWR), the fuel rod is made of dioxide of uranium (UO 2 ) pellet stacked in a metallic cladding. A multi scale and multi-physic approaches are needed for the simulation of fuel behavior under irradiation. The main phenomena to take into account are thermomechanical behavior of the fuel rod and chemical-physic behavior of the fission products. These last years one of the scientific issue to improve the simulation is to take into account the multi-physic coupling problem at the microscopic scale. The objective of this ph-D study is to contribute to this multi-scale approach. The present work concerns the micro-mechanical behavior of a polycrystalline aggregate of UO 2 . Mean field and full field approaches are considered. For the former and the later a self consistent homogenization technique and a periodic Finite Element model base on the 3D Voronoi pattern are respectively used. Fuel visco-plasticity is introduced in the model at the scale of a single grain by taking into account specific dislocation slip systems of UO 2 . A cohesive zone model has also been developed and implemented to simulate grain boundary sliding and intergranular crack opening. The effective homogenous behaviour of a Representative Volume Element (RVE) is fitted with experimental data coming from mechanical tests on a single pellet. Local behavior is also analyzed in order to evaluate the model capacity to assess micro-mechanical state. In particular, intra and inter granular stress gradient are discussed. A first validation of the local behavior assessment is proposed through the simulation of intergranular crack opening measured in a compressive creep test of a single fuel pellet. Concerning the impact of the microstructure on the fuel behavior under irradiation, a RVE simulation with a representative transient loading of a fuel rod during a power ramp test is achieved. The impact of local stress and strain heterogeneities on the multi

  20. Integrated biomass energy systems and emissions of carbon dioxide

    International Nuclear Information System (INIS)

    Boman, U.R.; Turnbull, J.H.

    1997-01-01

    Electric Power Research Institute (EPRI) and the US Department of Energy (DOE) have been funding a number of case studies under the initiative entitled ''Economic Development through Biomass Systems Integration'', with the objective of investigating the feasibility of integrated biomass energy systems utilizing a dedicated feedstock supply system (DFSS) for energy production. This paper deals with the full fuel cycle for four of these case studies, which have been examined with regard to the emissions of carbon dioxide., CO 2 . Although the conversion of biomass to electricity in itself does not emit more CO 2 than is captured by the biomass through photosynthesis, there will be some CO 2 emissions from the DFSS. External energy is required for the production and transportation of the biomass feedstock, and this energy is mainly based on fossil fuels. By using this input energy, CO 2 and other greenhouse gases are emitted. However, by utilizing biomass with fossil fuels as external input fuels, we would get about 10-15 times more electric energy per unit fossil fuel, compared with a 100% coal power system. By introducing a DFSS on former farmland the amount of energy spent for production of crops can be reduced, the amount of fertilizers can be decreased, the soil can be improved and a significant amount of energy will be produced compared with an ordinary farm crop. Compared with traditional coal-based electricity production, the CO 2 emissions are in the most cases reduced significantly by as much as 95%. The important conclusion is the great potential for reducing greenhouse gas emissions through the offset of coal by biomass. (author)