WorldWideScience

Sample records for supercritical steam temperatures

  1. Improvement of steam temperature control in supercritical once thru boilers

    OpenAIRE

    黒石, 卓司; 藤川, 卓爾

    2009-01-01

     New steam temperature control logic for supercritical once thru boilers was developed from the view point of simplicity similar to that of the conventional sub-critical drum type boilers. Water wall outlet steam temperature can be controlled more easily due to larger specific heat capacity of steam than super heater outlet steam temperature. By dividing temperature control into two parts, one at water wall outlet by fuel flow and the other at SH(super heater) outlet by SH spray flow, boiler ...

  2. Supercritical Once-through Boiler Main Steam Temperature Control%超临界直流锅炉主汽温的控制

    Institute of Scientific and Technical Information of China (English)

    丁超

    2014-01-01

    在超临界直流锅炉的运行过程中,主蒸汽温度是一个重要的参数,其控制方法与汽包锅炉不同。通过分析超临界直流锅炉主汽温控制的基本方法,以期对现场主汽温的控制起到理论指导的作用。%In the process of running a supercritical once-through boiler, the main steam temperature is an important parameter, which controls the different methods and drum boiler. This paper analyzes the basic method of supercritical once-through boiler main steam temperature control;with a view of the main steam temperature control of the scene plays the role of theoretical guidance.

  3. Incorporating supercritical steam turbines into molten-salt power tower plants :

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, James Edward; Wolf, Thorsten; Muley, Nishant

    2013-03-01

    Sandia National Laboratories and Siemens Energy, Inc., examined 14 different subcritical and supercritical steam cycles to determine if it is feasible to configure a molten-salt supercritical steam plant that has a capacity in the range of 150 to 200 MWe. The effects of main steam pressure and temperature, final feedwater temperature, and hot salt and cold salt return temperatures were determined on gross and half-net efficiencies. The main steam pressures ranged from 120 bar-a (subcritical) to 260 bar-a (supercritical). Hot salt temperatures of 566 and 600ÀC were evaluated, which resulted in main steam temperatures of 553 and 580ÀC, respectively. Also, the effects of final feedwater temperature (between 260 and 320ÀC) were evaluated, which impacted the cold salt return temperature. The annual energy production and levelized cost of energy (LCOE) were calculated using the System Advisory Model on 165 MWe subcritical plants (baseline and advanced) and the most promising supercritical plants. It was concluded that the supercritical steam plants produced more annual energy than the baseline subcritical steam plant for the same-size heliostat field, receiver, and thermal storage system. Two supercritical steam plants had the highest annual performance and had nearly the same LCOE. Both operated at 230 bar-a main steam pressure. One was designed for a hot salt temperature of 600ÀC and the other 565ÀC. The LCOEs for these plants were about 10% lower than the baseline subcritical plant operating at 120 bar-a main steam pressure and a hot salt temperature of 565ÀC. Based on the results of this study, it appears economically and technically feasible to incorporate supercritical steam turbines in molten-salt power tower plants.

  4. Thermodynamic properties of superheated and supercritical steam

    Energy Technology Data Exchange (ETDEWEB)

    Malhotra, A. [Indian Inst. of Technology, New Delhi (India). Dept. of Mechanical Engineering; Panda, D.M.R. [Dadri Gas Power Station, NTPC, Gautam Buddha Nagar (India)

    2001-07-01

    An existing formulation for steam properties is due to Irvine and Liley. Their equations are convenient to program and do not require excessive computational time to produce results. The properties computed from these equations compare favourably with standard data. An additional advantage of these equations is that they follow prescribed theoretical trends by reducing to perfect-gas behaviour away from the saturation dome. However, a difficulty with these equations is that, at pressures above 10 MPa and close to the saturation dome, unacceptably large errors (above 10%) are produced. These equations are examined in the present work with a view towards enhancing their range of application through the use of additional functions. It is shown that the errors may be reduced to within 1% over the entire range of pressures (both sub-critical and super-critical pressures) required in steam-plant calculations. (author)

  5. Thermal calculation and experimental studies on flue gas and steam temperature deviation of supercritical boiler%超临界锅炉烟温与汽温偏差热力计算与试验研究

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    针对大型电站超临界锅炉烟温与汽温偏差问题,结合国内首台600 MW超临界W型锅炉,重点研究不同负荷下汽水分离器出口汽温偏差,以及尾部受热面汽温偏差变化规律,并从优化汽温偏差出发,首次提出汽水分离器出口管道交叉布置结构,从而改变汽水流动方向,并结合锅炉热力计算,验证交叉布置结构减少汽温偏差的效果:当采用汽水分离器出口交叉布置结构后,屏式过热器入口左、右侧汽温偏差减小到原汽温偏差的1/2左右。%To solve the problems of flue gas and steam temperature deviation of supercritical boiler, the temperature deviation of the steam separator and the following heating surface are investigated in the domestic first 600 MW supercritical W-shaped flame boiler. Moreover, a special outlet cross layout structure of steam separator is designed and the role of the special outlet cross structure is investigated by thermal calculation. The results indicate that the steam temperature deviation of supercritical boiler is increased with the the flue gas temperature deviation and the growth of the following heating surface during actual operation. Meanwhile, the special outlet cross layout structure of steam separator has a remarkable effect on decreasing the steam temperature deviation, which has been reduced to half of the original level. Therefore, the special outlet cross layout structure of supercritical boiler steam separator is worthwhile to distinctly decrease the steam temperature deviation and increase the safe in operation of supercritical boil.

  6. Analysis of the temperature distribution of a water wall in the furnace of a supercritical steam power plant

    Energy Technology Data Exchange (ETDEWEB)

    Matsumura, Norihide; Yagi, Nobuyoshi; Shibayama, Motoaki; Hayasaka, Hiroshi

    1988-07-25

    It is one of the important subjects for maintenance and management of modern boilers to establish the technology for estimating the residual life of a water wall tube composing a boiler furnace for a thermal power plant. Various studies on the residual life of material itself for a boiler water-wall tube have so far been in progress, but concerning a temperature of a water wall tube at a particular place inside a boiler furnace, the development of a practical method of analysis estimating the amount of the radiant heat transfer has not so far been progressed. Accordingly, in this report, a practical method for obtaining the temperature distribution of a water wall tube was examined and an idea that the radiant heat ray method was used for the analysis of radiant heat transfer and at the same time, the actual result of the operation was used for steam flow rate, etc. was elaborated and brought into operation. As a result, the following was revealed inter alia: (1) The heat flux became the maximum around the uppermost stages of the burners of the front and rear walls. (2) The temperature of a tube wall became the maximum around the uppermost stages of the burners in the center of the wall. (3) Deviation of the flow distribution affected the wall tube temperature considerably. The above is considered to suggest the adequacy of this analytical method. (12 figs, 9 refs)

  7. I000MW超超临界机组过热汽温控制策略%Controlling strategy to the superheated steam temperature for 1000MW supercritical unit

    Institute of Scientific and Technical Information of China (English)

    宋强; 石磐

    2011-01-01

    Guangzhou Taishan 1000MW supercritical unit , as an example,the paper analyzes dynamic characteristic of the superheated steam temperature control for supercritical Unit of dynamic characteristic and discusses control strategy to superheated steam temperature fuel - water ratio and desuperheating water control. Finally, according to the practical examples, the paper carries out deliberate analysis and research.%以广州台山1000MW超超临界机组为例,分析了超超临界机组过热汽温控制的动态特性,论述了过热汽温控制中的燃水比和减温水控制策略,并根据实例进行了详细的分析和研究。

  8. 1000 MW ultra-supercritical turbine steam parameter optimization

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The 2 ×1000 MW ultra-supercritical steam turbine of Shanghai Waigaoqiao Phase Ⅲ project,which uses grid frequency regulation and overload control through an overload valve,is manufactured by Shanghai Turbine Company using Siemens technology.Through optimization,the steam pressure is regarded as the criterion between constant pressure and sliding pressure operation.At high circulating water temperature,the turbine overload valve is kept closed when the unit load is lower than 1000 MW while at other circulating water temperatures the turbine can run in sliding pressure operation when the unit load is higher than 1000 MW and the pressure is lower than 27 MPa This increases the unit operation efficiency.The 3D bending technology in the critical piping helps to reduce the project investment and minimize the reheat system pressure drop which improves the unit operation efficiency and safety.By choosing lower circulating water design temperature and by setting the individual Boiler Feedwater Turbine condenser to reduce the exhaust steam flow and the heat load to the main condenser,the unit average back pressure and the terminal temperature difference are minimized.Therefore,the unit heat efficiency is increased.

  9. Steam Oxidation and Chromia Evaporation in Ultra-Supercritical Steam Boilers and Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Gordon H. Holcomb

    2009-01-01

    U.S. Department of Energy’s goals include power generation from coal at 60% efficiency, which requires steam conditions of up to 760 °C and 340 atm, so-called ultra-supercritical (USC) conditions. Evaporation of protective chromia scales is expected to be a primary corrosion mechanism. A methodology to calculate Cr evaporation rates from chromia scales was developed and combined with Cr diffusion calculations within the alloy (with a constant flux of Cr leaving the alloy from evaporation) to predict Cr concentration profiles and to predict the time until breakaway oxidation. At the highest temperatures and pressures, the time until breakaway oxidation was predicted to be quite short for the turbine blade, and of concern within the steam pipe and the higher temperature portions of the superheater tube. Alloy additions such as Ti may allow for a reduction in evaporation rate with time, mitigating the deleterious effects of chromia evaporation.

  10. Topping PCFB combustion plant with supercritical steam pressure

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, A. [Foster Wheeler Development Corp., Livingston, NJ (United States); White, J. [Parsons Power Group Inc., Reading, PA (United States)

    1997-11-01

    Research is being conducted to develop a new type of coal fired plant for electric power generation. This new type of plant, called a second generation or topping pressurized circulating fluidized bed combustion (topping PCFB) plant, offers the promise of efficiencies greater than 46 percent (HHV), with both emissions and a cost of electricity that are significantly lower than conventional pulverized coal fired plants with scrubbers. The topping PCFB plant incorporates the partial gasification of coal in a carbonizer, the combustion of carbonizer char in a pressurized circulating fluidized bed combustor (PCFB), and the combustion of carbonizer fuel gas in a topping combustor to achieve gas turbine inlet temperatures of 2,300 F and higher. After completing pilot plant tests of a carbonizer, a PCFB, and a gas turbine topping combustor, all being developed for this new plant, the authors calculated a higher heating value efficiency of 46.2 percent for the plant. In that analysis, the plant operated with a conventional 2,400 psig steam cycle with 1,000 F superheat and reheat steam and a 2.5 inch mercury condenser back pressure. This paper identifies the efficiency gains that this plant will achieve by using supercritical pressure steam conditions.

  11. Exploration of Adopting 623 ℃ Reheat Steam Temperature in 660-MW Ultra-Supercritical Type Ⅱ Boilers%660 MW超超临界Ⅱ型锅炉再热汽温623 ℃探索

    Institute of Scientific and Technical Information of China (English)

    翟德双

    2013-01-01

    The 623℃ reheat steam temperature will be adopted for two 660-MW ultra-supercritical units in phase Ⅱ of a power plant project. This is the first case for type Ⅱ boilers in the world. The operation of the 660-MW ultra-supercritical units with 603 ℃ reheat steam temperature is introduced, and then the design of elevating the reheat steam temperature up to 623℃ is presented. Further, related economic analysis is conducted and security measures are proposed. Finally, some suggestions on the installation, debugging and operation of the two boilers are also included.%某电厂二期工程2台660 MW超超临界机组再热汽温选择623C高参数,在全球的Ⅱ型锅炉中将是首次采用.介绍了目前660 MW超超临界机组冉热汽温603℃的使用运行情况,分析提出了再热汽温提高到623℃的相关设计方案及相应的安全措施,并进行了经济性分析,指出锅炉在安装、调试和运行中应注意的问题.

  12. 超临界直流炉主蒸汽温度控制积分饱和问题解决方法%Solution of Integral Saturationon Steam Temperature Control in Supercritical Monotubeboiler

    Institute of Scientific and Technical Information of China (English)

    蒋明达

    2015-01-01

    The paper introduces the cause and its effect and puts forward a solution to the problem of integral saturation in main steam temperature control system in Luohe Power Plant of Datang Power's #6 supercritical monotube boiler.%本文分析了超临界直流炉主蒸汽温度控制积分饱和问题产生原因及影响,对大唐洛河发电厂#6超临界直流锅炉主蒸汽温控制系统出现的积分饱和问题提出了解决方案.

  13. Steam-Reheat Option for Supercritical-Water-Cooled Reactors

    Science.gov (United States)

    Saltanov, Eugene

    SuperCritical-Water-cooled Reactors (SCWRs) are being developed as one of the Generation-IV nuclear-reactor concepts. Main objectives of the development are to increase thermal efficiency of a Nuclear Power Plant (NPP) and to decrease capital and operational costs. The first objective can be achieved by introducing nuclear steam reheat inside a reactor and utilizing regenerative feedwater heaters. The second objective can be achieved by designing a steam cycle that closely matches that of the mature supercritical fossil-fuelled power plants. The feasibility of these objectives is discussed. As a part of this discussion, heat-transfer calculations have been performed and analyzed for SuperCritical-Water (SCW) and SuperHeated-Steam (SHS) channels of the proposed reactor concept. In the calculations a uniform and three non-uniform Axial Heat Flux Profiles (AHFPs) were considered for six different fuels (UO2, ThO 2, MOX, UC2, UC, and UN) and at average and maximum channel power. Bulk-fluid, sheath, and fuel centerline temperatures as well as the Heat Transfer Coefficient (HTC) profiles were obtained along the fuel-channel length. The HTC values are within a range of 4.7--20 kW/m2·K and 9.7--10 kW/m2·K for the SCW and SHS channels respectively. The main conclusion is that while all the mentioned fuels may be used for the SHS channel, only UC2, UC, or UN are suitable for a SCW channel, because their fuel centerline temperatures are at least 1000°C below melting point, while that of UO2, ThO2 , and MOX may reach melting point.

  14. Improved Sterilization of Sensitive Biomaterials with Supercritical Carbon Dioxide at Low Temperature: e0129205

    National Research Council Canada - National Science Library

    Anne Bernhardt; Markus Wehrl; Birgit Paul; Thomas Hochmuth; Matthias Schumacher; Kathleen Schütz; Michael Gelinsky

    2015-01-01

    ... sterilization procedures like steam, ethylene oxide treatment or gamma irradiation. Supercritical CO2 (scCO2) treatment is a promising strategy for the terminal sterilization of sensitive biomaterials at low temperature...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-02-26

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

  16. Neural Network Internal Model Control for Superheated Steam Temperature of Supercritical Boiler Unit%超临界锅炉过热汽温神经网络内模控制

    Institute of Scientific and Technical Information of China (English)

    马良玉; 冯谦; 易祖耀

    2013-01-01

    锅炉过热汽温是燃煤机组运行中的重要参数,过高、过低都会对机组的安全经济运行构成威胁.由于锅炉结构复杂,系统庞大,汽温对象具有变时滞、变参数等特性,喷水减温系统采用的串级PID控制,在大范围变工况下效果往往很不理想,且PID参数整定耗时耗力.为此,该文针对600 MW超临界锅炉过热器的喷水减温系统,研究了过热汽温神经网络(ANN)内模控制方案.基于Matlab建立了汽温系统的ANN正模型和逆模型,并设计出ANN内模实时控制器.仿真表明,与原串级PID控制相比,该方案显著改善了过热汽温的控制品质.%Boiler SST was an important parameter closely related to the safe and economic operation of a coal-fired power plant. Superheated steam temperature either too high or too low will pose a threat on the operation safety and economy. Because the boiler superheater system was relatively complex with large delay,large inertia and higher non-linearity, satisfactory control effects can often not be obtained with conventional cascade PID control scheme at wide operating range. Retuning of the PID parameters was often a time-consuming and labor-intensive work. For this reason, a neural network IMC scheme was studied for the two-stage desuperheating system of a 600 MW supercritical boiler unit, studying the system with the method based on superheated steam temperature control scheme. The neural network direct models and inverse models of the superheater system are built and trained with MATLAB software. Then neural network model based IMC controllers for the superheated steam temperature were designed,programmed and tested with a full-scope power plant simulator. It was shown that the neural network IMC scheme can significantly improve the superheated steam temperature control quality compared to the original cascade PID control.

  17. Review of the coal-fired, over-supercritical and ultra-supercritical steam power plants

    Science.gov (United States)

    Tumanovskii, A. G.; Shvarts, A. L.; Somova, E. V.; Verbovetskii, E. Kh.; Avrutskii, G. D.; Ermakova, S. V.; Kalugin, R. N.; Lazarev, M. V.

    2017-02-01

    The article presents a review of developments of modern high-capacity coal-fired over-supercritical (OSC) and ultra-supercritical (USC) steam power plants and their implementation. The basic engineering solutions are reported that ensure the reliability, economic performance, and low atmospheric pollution levels. The net efficiency of the power plants is increased by optimizing the heat balance, improving the primary and auxiliary equipment, and, which is the main thing, by increasing the throttle conditions. As a result of the enhanced efficiency, emissions of hazardous substances into the atmosphere, including carbon dioxide, the "greenhouse" gas, are reduced. To date, the exhaust steam conditions in the world power industry are p 0 ≈ 30 MPa and t 0 = 610/620°C. The efficiency of such power plants reaches 47%. The OSC plants are being operated in Germany, Denmark, Japan, China, and Korea; pilot plants are being developed in Russia. Currently, a project of a power plant for the ultra-supercritical steam conditions p 0 ≈ 35 MPa and t 0 = 700/720°C with efficiency of approximately 50% is being studied in the EU within the framework of the Thermie AD700 program, project AD 700PF. Investigations in this field have also been launched in the United States, Japan, and China. Engineering solutions are also being sought in Russia by the All-Russia Thermal Engineering Research Institute (VTI) and the Moscow Power Engineering Institute. The stated steam parameter level necessitates application of new materials, namely, nickel-base alloys. Taking into consideration high costs of nickel-base alloys and the absence in Russia of technologies for their production and manufacture of products from these materials for steam-turbine power plants, the development of power plants for steam parameters of 32 MPa and 650/650°C should be considered to be the first stage in creating the USC plants as, to achieve the above parameters, no expensive alloys are require. To develop and

  18. Influence of steam leakage through vane, gland, and shaft seals on rotordynamics of high-pressure rotor of a 1,000 MW ultra-supercritical steam turbine

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, P.N. [Shanghai Jiao Tong University, Key Laboratory of Power Machinery and Engineering, Ministry of Education, School of Mechanical Engineering, Shanghai (China); Shanghai Turbine Company, Department of R and D, Shanghai (China); Wang, W.Z.; Liu, Y.Z. [Shanghai Jiao Tong University, Key Laboratory of Power Machinery and Engineering, Ministry of Education, School of Mechanical Engineering, Shanghai (China); Meng, G. [Shanghai Jiao Tong University, State Key Laboratory of Mechanical System and Vibration, School of Mechanical Engineering, Shanghai (China)

    2012-02-15

    A comparative analysis of the influence of steam leakage through vane, gland, and shaft seals on the rotordynamics of the high-pressure rotor of a 1,000 MW ultra-supercritical steam turbine was performed using numerical calculations. The rotordynamic coefficients associated with steam leakage through the three labyrinth seals were calculated using the control-volume method and perturbation analysis. A stability analysis of the rotor system subject to the steam forcing induced by the leakage flow was performed using the finite element method. An analysis of the influence of the labyrinth seal forcing on the rotordynamics was carried out by varying the geometrical parameters pertaining to the tooth number, seal clearance, and inner diameter of the labyrinth seals, along with the thermal parameters with respect to pressures and temperatures. The results demonstrated that the steam forcing with an increase in the length of the blade for the vane seal significantly influences the rotordynamic coefficients. Furthermore, the contribution of steam forcing to the instability of the rotor is decreased and increased with increases in the seal clearance and tooth number, respectively. The comparison of the rotordynamic coefficients associated with steam leakage through the vane seal, gland seal, and shaft seal convincingly disclosed that, although the steam forcing attenuates the stability of the rotor system, the steam turbine is still operating under safe conditions. (orig.)

  19. Cooling performance of grid-sheets for highly loaded ultra-supercritical steam turbines

    Institute of Scientific and Technical Information of China (English)

    Dieter BOHN; Robert KREWINKEL; Shuqing TIAN

    2009-01-01

    In order to increase efficiency and achieve a further CO2-reduction, the next generation of power plant turbines will have steam turbine inlet temperatures that are considerably higher than the current ones. The high pressure steam turbine inlet temperature is expected to be increased up to approximately 700℃ with a live steam pressure of 30 MPa. The elevated steam parameters in the high and intermediate pressure turbines can be encountered with Ni-base alloys, but this is a costly alternative associated with many manufacturing difficulties. Colla-borative research centre 561 "Thermally Highly Loaded,Porous and Cooled Multi-Layer Systems for Combined Cycle Power Plants" at RWTH Aachen University proposes cooling the highly loaded turbines instead, as this would necessitate the application of far less Ni-base alloys.To protect the thermally highly loaded components, a sandwich material consisting of two thin face sheets and a core made from a woven wire mesh is used to cover the walls of the steam turbine casing. The cooling steam is led through the woven wire mesh between the two face sheets to achieve a cooling effect. The wire mesh provides the grid-sheet with structural rigidity under varying operating conditions.In the present work, the cooling performance of the grid-sheets will be investigated applying the conjugate heat transfer method to ultra-supercritical live and cooling steam conditions for a section of the cooling structure. The behaviour of the flow and the heat transfer in the grid-sheet will be analyzed in detail using a parameter variation. The numerical results should give a first prediction of the cooling performance under future operating conditions.

  20. Development of Steam Turbine Inlet Control Valve for Supercritical Pressure at Siemens Industrial Turbomachinery AB

    OpenAIRE

    Sors, Felix; Holm, Patrik

    2010-01-01

    The development in the steam turbine business is heading for applications with much higher steam parameters since this enables a raised efficiency. Steam parameters refer to the pressure and the temperature of the steam. The aim of this study was to generate concepts for steam turbine inlet control valves designed for higher pressure and temperature in comparison with the present design. Future steam power plants using solar energy, based on tower technology, request this kind of performance ...

  1. Next Generation Engineered Materials for Ultra Supercritical Steam Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Douglas Arrell

    2006-05-31

    To reduce the effect of global warming on our climate, the levels of CO{sub 2} emissions should be reduced. One way to do this is to increase the efficiency of electricity production from fossil fuels. This will in turn reduce the amount of CO{sub 2} emissions for a given power output. Using US practice for efficiency calculations, then a move from a typical US plant running at 37% efficiency to a 760 C /38.5 MPa (1400 F/5580 psi) plant running at 48% efficiency would reduce CO2 emissions by 170kg/MW.hr or 25%. This report presents a literature review and roadmap for the materials development required to produce a 760 C (1400 F) / 38.5MPa (5580 psi) steam turbine without use of cooling steam to reduce the material temperature. The report reviews the materials solutions available for operation in components exposed to temperatures in the range of 600 to 760 C, i.e. above the current range of operating conditions for today's turbines. A roadmap of the timescale and approximate cost for carrying out the required development is also included. The nano-structured austenitic alloy CF8C+ was investigated during the program, and the mechanical behavior of this alloy is presented and discussed as an illustration of the potential benefits available from nano-control of the material structure.

  2. Temperature Control via Affine Nonlinear Systems for Intermediate Point of Supercritical Once-Through Boiler Units

    OpenAIRE

    Hong Zhou; Changkun Liu; Zhi-Wei Liu; Wenshan Hu

    2014-01-01

    For the operation of the supercritical once-through boiler generation units, the control of the temperature at intermediate point (IPT) is highly significant. IPT is the steam temperature at the outlet of the separator. Currently, PID control algorithms are widely adopted for the IPT control. However, PID cannot achieve the optimal performances as the units’ dynamic characteristic changes at different working points due to the severe nonlinearity. To address the problem, a new control algorit...

  3. Features of steam turbine cooling by the example of an SKR-100 turbine for supercritical steam parameters

    Science.gov (United States)

    Arkadyev, B. A.

    2015-10-01

    Basic principles of cooling of high-temperature steam turbines and constructive solutions used for development of the world's first cooled steam turbine SKR-100 (R-100-300) are described. Principal differences between the thermodynamic properties of cooling medium in the steam and gas turbines and the preference of making flow passes of cooled cylinders of steam turbines as reactive are shown. Some of its operation results and their conclusions are given. This turbine with a power of 100 MW, initial steam parameters approximately 30 MPa and 650°C, and back pressure 3 MPa was made by a Kharkov turbine plant in 1961 and ran successfully at a Kashira GRES (state district power plant) up to 1979, when it was taken out of use in a still fully operating condition. For comparison, some data on construction features and operation results of the super-high pressure cylinder of steam turbines of American Philo 6 (made by General Electric Co.) and Eddystone 1 (made by Westinghouse Co.) power generating units, which are close to the SKR-100 turbine by design initial steam parameters and the implementation time, are given. The high operational reliability and effectiveness of the cooling system that was used in the super-high pressure cylinder of the SKR-100 turbine of the power-generating unit, which were demonstrated in operation, confirms rightfulness and expediency of principles and constructive solutions laid at its development. As process steam temperatures are increased, the realization of the proposed approach to cooling of multistage turbines makes it possible to limit for large turbine parts the application of new, more expensive high-temperature materials, which are required for making steam boilers, and, in some cases, to do completely away with their utilization.

  4. An experimental study on flowrate and stability for 600MW supercritical steam-turbine control valve

    Institute of Scientific and Technical Information of China (English)

    相晓伟; 毛靖儒; 孙弼

    2007-01-01

    An experimental study on flowrate and stability of a type of control valve of 600MW supercritical steam-turbine was presented by measuring instruments of static, dynamic pressure and vibration in self-designed test rig. The investigation shows that flow coefficient is 30% up more than that of the control valve of GX-1 type used widely in domestic power plants now, as small-medium lifts. If the relative lift (h/D) is less than 20%, the valve can always work steadily in all the pressure ratios. When the h/D i...

  5. Coupling of Modular High-Temperature Gas-Cooled Reactor with Supercritical Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Shutang Zhu

    2008-01-01

    Full Text Available This paper presents investigations on the possible combination of modular high-temperature gas-cooled reactor (MHTGR technology with the supercritical (SC steam turbine technology and the prospective deployments of the MHTGR SC power plant. Energy conversion efficiency of steam turbine cycle can be improved by increasing the main steam pressure and temperature. Investigations on SC water reactor (SCWR reveal that the development of SCWR power plants still needs further research and development. The MHTGR SC plant coupling the existing technologies of current MHTGR module design with operation experiences of SC FPP will achieve high cycle efficiency in addition to its inherent safety. The standard once-reheat SC steam turbine cycle and the once-reheat steam cycle with life-steam have been studied and corresponding parameters were computed. Efficiencies of thermodynamic processes of MHTGR SC plants were analyzed, while comparisons were made between an MHTGR SC plant and a designed advanced passive PWR - AP1000. It was shown that the net plant efficiency of an MHTGR SC plant can reach 45% or above, 30% higher than that of AP1000 (35% net efficiency. Furthermore, an MHTGR SC plant has higher environmental competitiveness without emission of greenhouse gases and other pollutants.

  6. Modeling Creep-Fatigue-Environment Interactions in Steam Turbine Rotor Materials for Advanced Ultra-supercritical Coal Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Chen [General Electric Global Research, Niskayuna, NY (United States)

    2014-04-01

    The goal of this project is to model creep-fatigue-environment interactions in steam turbine rotor materials for advanced ultra-supercritical (A-USC) coal power Alloy 282 plants, to develop and demonstrate computational algorithms for alloy property predictions, and to determine and model key mechanisms that contribute to the damages caused by creep-fatigue-environment interactions.

  7. Corrosion of several metals in supercritical steam at 538/sup 0/C. [85 alloys

    Energy Technology Data Exchange (ETDEWEB)

    McCoy, H. E.; McNabb, B.

    1977-05-01

    The corrosion of several iron- and nickel-base alloys in supercritical steam at 24.1 MPa (3500 psi) and 538/sup 0/C was measured to 7.92 x 10/sup 7/ s (22,000 h). The experiments were carried out in TVA's Bull Run Steam Plant. Corrosion was measured almost entirely by weight change and visual appearance; a few samples were evaluated by more descriptive analytical techniques. The corrosion rates of low-alloy ferritic steels containing from 1.1 to 8.7 percent Cr and 0.5 to 1.0 percent Mo differed by less than a factor of 2 in steam. Several modified compositions of Hastelloy N were evaluated and found to corrode at about equivalent rates. Of the alloys studied, the lowest weight gain in 3.6 x 10/sup 7/ sec (10,000 hr) was 0.01 mg/cm/sup 2/ for Inconel 718 and the highest 10 mg/cm/sup 2/ for the low-alloy ferritic steels. 25 figures, 3 tables.

  8. Corrosion and Creep of Candidate Alloys in High Temperature Helium and Steam Environments for the NGNP

    Energy Technology Data Exchange (ETDEWEB)

    Was, Gary; Jones, J. W.

    2013-06-21

    This project aims to understand the processes by which candidate materials degrade in He and supercritical water/steam environments characteristic of the current NGNP design. We will focus on understanding the roles of temperature, and carbon and oxygen potential in the 750-850 degree C range on both uniform oxidation and selective internal oxidation along grain boundaries in alloys 617 and 800H in supercritical water in the temperature range 500-600 degree C; and examining the application of static and cyclic stresses in combination with impure He environments in the temperature rang 750-850 degree C; and examining the application of static and cyclic stresses in combination with impure He environments in the temperature range 750-850 degree C over a range of oxygen and carbon potentials in helium. Combined, these studies wil elucidate the potential high damage rate processes in environments and alloys relevant to the NGNP.

  9. An experimental study on flowrate and stability for 600MW supercritical steam-turbine control valve

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An experimental study on flowrate and stability of a type of control valve of 600MW supercritical steam-turbine was presented by measuring instruments of static, dynamic pressure and vibration in self-designed test rig. The investigation shows that flow coefficient is 30% up more than that of the control valve of GX-1 type used widely in domestic power plants now, as small-medium lifts. If the relative lift (h/D) is less than 20%, the valve can always work steadily in all the pressure ratios. When the h/D is between 20% to 24%, big vibration of valve stem occurs if the pressure ratio is between 0.7 to 0.8. When h/D is more than 25%, relatively great vibration happens in a wide range of pressure ratios of 0.4 to 0.85.

  10. Linear parameter-varying modeling and control of the steam temperature in a Canadian SCWR

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Peiwei, E-mail: sunpeiwei@mail.xjtu.edu.cn; Zhang, Jianmin; Su, Guanghui

    2017-03-15

    Highlights: • Nonlinearity of Canadian SCWR is analyzed based on step responses and Nyquist plots. • LPV model is derived through Jacobian linearization and curve fitting. • An output feedback H{sub ∞} controller is synthesized for the steam temperature. • The control performance is evaluated by step disturbances and wide range operation. • The controller can stabilize the system and reject the reactor power disturbance. - Abstract: The Canadian direct-cycle Supercritical Water-cooled Reactor (SCWR) is a pressure-tube type SCWR under development in Canada. The dynamics of the steam temperature have a high degree of nonlinearity and are highly sensitive to reactor power disturbances. Traditional gain scheduling control cannot theoretically guarantee stability for all operating regions. The control performance can also be deteriorated when the controllers are switched. In this paper, a linear parameter-varying (LPV) strategy is proposed to solve such problems. Jacobian linearization and curve fitting are applied to derive the LPV model, which is verified using a nonlinear dynamic model and determined to be sufficiently accurate for control studies. An output feedback H{sub ∞} controller is synthesized to stabilize the steam temperature system and reject reactor power disturbances. The LPV steam temperature controller is implemented using a nonlinear dynamic model, and step changes in the setpoints and typical load patterns are carried out in the testing process. It is demonstrated through numerical simulation that the LPV controller not only stabilizes the steam temperature under different disturbances but also efficiently rejects reactor power disturbances and suppresses the steam temperature variation at different power levels. The LPV approach is effective in solving control problems of the steam temperature in the Canadian SCWR.

  11. Materials for Advanced Ultra-supercritical (A-USC) Steam Turbines – A-USC Component Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Purgert, Robert [Energy Industries Of Ohio Inc., Independence, OH (United States); Phillips, Jeffrey [Energy Industries Of Ohio Inc., Independence, OH (United States); Hendrix, Howard [Energy Industries Of Ohio Inc., Independence, OH (United States); Shingledecker, John [Energy Industries Of Ohio Inc., Independence, OH (United States); Tanzosh, James [Energy Industries Of Ohio Inc., Independence, OH (United States)

    2016-10-01

    The work by the United States Department of Energy (U.S. DOE)/Ohio Coal Development Office (OCDO) advanced ultra-supercritical (A-USC) Steam Boiler and Turbine Materials Consortia from 2001 through September 2015 was primarily focused on lab scale and pilot scale materials testing. This testing included air- or steam-cooled “loops” that were inserted into existing utility boilers to gain exposure of these materials to realistic conditions of high temperature and corrosion due to the constituents in the coal. Successful research and development resulted in metallic alloy materials and fabrication processes suited for power generation applications with metal temperatures up to approximately 1472°F (800°C). These materials or alloys have shown, in extensive laboratory tests and shop fabrication studies, to have excellent applicability for high-efficiency low CO2 transformational power generation technologies previously mentioned. However, as valuable as these material loops have been for obtaining information, their scale is significantly below that required to minimize the risk associated with a power company building a multi-billion dollar A-USC power plant. To decrease the identified risk barriers to full-scale implementation of these advanced materials, the U.S. DOE/OCDO A-USC Steam Boiler and Turbine Materials Consortia identified the key areas of the technology that need to be tested at a larger scale. Based upon the recommendations and outcome of a Consortia-sponsored workshop with the U.S.’s leading utilities, a Component Test (ComTest) Program for A-USC was proposed. The A-USC ComTest program would define materials performance requirements, plan for overall advanced system integration, design critical component tests, fabricate components for testing from advanced materials, and carry out the tests. The AUSC Component Test was premised on the program occurring at multiple facilities, with the operating temperatures, pressure and/or size of

  12. Thermodynamic evaluation of supercritical oxy-type power plant with high-temperature three-end membrane for air separation

    Directory of Open Access Journals (Sweden)

    Kotowicz Janusz

    2014-09-01

    Full Text Available Among the technologies which allow to reduce greenhouse gas emissions, mainly of carbon dioxide, special attention deserves the idea of ‘zero-emission’ technology based on boilers working in oxy-combustion technology. In the paper a thermodynamic analysis of supercritical power plant fed by lignite was made. Power plant consists of: 600 MW steam power unit with live steam parameters of 650 °C/30 MPa and reheated steam parameters of 670 °C/6 MPa; circulating fluidized bed boiler working in oxy-combustion technology; air separation unit and installation of the carbon dioxide compression. Air separation unit is based on high temperature membrane working in three-end technology. Models of steam cycle, circulation fluidized bed boiler, air separation unit and carbon capture installation were made using commercial software. After integration of these models the net electricity generation efficiency as a function of the degree of oxygen recovery in high temperature membrane was analyzed.

  13. Thermodynamic evaluation of supercritical oxy-type power plant with high-temperature three-end membrane for air separation

    Science.gov (United States)

    Kotowicz, Janusz; Balicki, Adrian; Michalski, Sebastian

    2014-09-01

    Among the technologies which allow to reduce greenhouse gas emissions, mainly of carbon dioxide, special attention deserves the idea of `zero-emission' technology based on boilers working in oxy-combustion technology. In the paper a thermodynamic analysis of supercritical power plant fed by lignite was made. Power plant consists of: 600 MW steam power unit with live steam parameters of 650 °C/30 MPa and reheated steam parameters of 670 °C/6 MPa; circulating fluidized bed boiler working in oxy-combustion technology; air separation unit and installation of the carbon dioxide compression. Air separation unit is based on high temperature membrane working in three-end technology. Models of steam cycle, circulation fluidized bed boiler, air separation unit and carbon capture installation were made using commercial software. After integration of these models the net electricity generation efficiency as a function of the degree of oxygen recovery in high temperature membrane was analyzed.

  14. Steam Temperature Control of Plasma Ignition Start of Ultra-Supercritical Unit%超超临界机组等离子点火启动汽温控制

    Institute of Scientific and Technical Information of China (English)

    孙磊

    2013-01-01

    本文介绍了超超临界机组在整套启动期间,采用等离子点火燃煤启动时,易发生的超温等不良现象,分析其原因和危害,并提出了针对性的解决措施。%This paper introduces that the overheating and other undesirable phenomena of ultra supercritical units easily occurred when using plasma ignition to start coal during the entire startup, and analyzes causes and hazards, proposes specific measures.

  15. Temperature Fluctuation Characteristics Analysis for Steam Generator of Fast Reactor

    Institute of Scientific and Technical Information of China (English)

    ZHU; Li-na; WU; Zhi-guang

    2015-01-01

    In the case of boiling heat transfer deterioration,temperature fluctuating may accelerate the corrosion of heat transfer tubes and can also lead to thermal stress on the tubes.In this paper,dryout-induced temperature fluctuation for the fast reactor steam generator is investigated.The impacts of water flow rate,sodium inlet temperature and the outlet steam

  16. [Comparison of supercritical fluid extraction and steam distillation methods for the extraction of essential oils from Schizonepeta tenuifolia Briq].

    Science.gov (United States)

    Qiu, Qin; Ling, Jianya; Ding, Yuping; Chang, Hongwen; Wang, Jiang; Liu, Tingli

    2005-11-01

    Essential oil was extracted from Schizonepeta tenuifolia Briq. by supercritical fluid extraction (SFE) and steam distillation (SD). The components extracted were determined by gas chromatography with area normalization method and identified by gas chromatography-mass spectrometry (GC-MS). The optimal chromatographic conditions were: capillary column, SE-54 (30 m x 0.25 mm i.d., 0.25 microm); column temperature, 50 degrees C (3 min) --> (5 degrees c/min) 180 degrees C (2 min --> (10 degrees C/ min) 260 degrees C 50 min); split injection, split ratio 1: 50; injector temperature, 280 degrees C. Fifty-four components were identified for the essential oils extracted by SFE, and its main components were found to be pulegone, menthone, linoleic acid chloride etc. Thirty-nine components were identified for the essential oil obtained by SD, and its main components were found to be pulegone, menthone, limonene etc. The SFE method is better than the SD method in reliability stability and reproducibility, and is thus well suitable for similar applications involving for extraction of other traditional Chinese herbal medicines.

  17. Oxidation performance of high temperature steels and coatings for future supercritical power plants

    Energy Technology Data Exchange (ETDEWEB)

    Auerkari, Pertti; Salonen, Jorma; Toivonen, Aki; Penttilae, Sami [VTT, Espoo (Finland); Haekkilae, Juha [Foster Wheeler Energia, Varkaus (Finland); Aguero, Alina; Gutierrez, Marcos; Muelas, Raul [INTA, Madrid (Spain); Fry, Tony [NPL (United Kingdom)

    2010-07-01

    The operating efficiency of current and future thermal power plants is largely dependent on the applied temperature and pressure, which are in part limited by the internal oxidation resistance of the structural materials in the steam systems. Alternative and reference materials for such systems have been tested within the COST 536 (ACCEPT) project, including bulk reference materials (ferritic P92 and austenitic 316 LN steels) and several types of coatings under supercritical combined (oxygen) water chemistry (150 ppb DO) at 650 C/300 bar. The testing results from a circulating USC autoclave showed that under such conditions the reference bulk steels performed poorly, with extensive oxidation already after relatively short term exposure to the supercritical medium. Better protection was attained by suitable coatings, although there were clear differences in the protective capabilities between different coating types, and some challenges remain in applying (and repairing) coatings for the internal surfaces of welded structures. The materials performance seems to be worse in supercritical than in subcritical conditions, and this appears not to be only due to the effect of temperature. The implications are considered from the point of view of the operating conditions and materials selection for future power plants. (orig.)

  18. AUTOMATIC CONTROL SYSTEM OF THE DRUM BOILER SUPERHEATED STEAM TEMPERATURE.

    Directory of Open Access Journals (Sweden)

    Juravliov A.A.

    2006-04-01

    Full Text Available The control system of the temperature of the superheated steam of the drum boiler is examined. Main features of the system are the PI-controller in the external control loop and introduction of the functional component of the error signal of the external control loop with the negative feedback of the error signal between the prescribed value of steam flowrate and the signal of the steam flowrate in the exit of the boiler in the internal control loop.

  19. Simulation of heat transfer in combustion chamber waterwall tubes of supercritical steam boilers

    Directory of Open Access Journals (Sweden)

    Grądziel Sławomir

    2016-06-01

    Full Text Available The paper presents the results of numerical computations performed for the furnace chamber waterwalls of a supercritical boiler with a steam output of 2400 × 103 kg/h. A model of distributed parameters is proposed for the waterwall operation simulation. It is based on the solution of equations describing the mass, momentum and energy conservation laws. The aim of the calculations was to determine the distribution of enthalpy, mass flow and fluid pressure in tubes. The balance equations can be brought to a form where on the left-hand side space derivatives, and on the right-hand side – time derivatives are obtained. The time derivatives on the right-hand side were replaced with backward difference quotients. This system of ordinary differential equations was solved using the Runge-Kutta method. The calculation also takes account of the variable thermal load of the chamber along its height. This thermal load distribution is known from the calculations of the heat exchange in the combustion chamber. The calculations were carried out with the zone method.

  20. Research on Control Method for Intermediate Point Temperature of Supercritical Boiler Based on Active Disturbance Rejection Cascade Control

    Directory of Open Access Journals (Sweden)

    Junjie Gu

    2013-07-01

    Full Text Available As the important signal of once-through boiler's water-fuel ratio control, intermediate point temperature of supercritical boiler plays a key role in the decision of steam and water’s boundary, the match of fuel and water, the control of main steam temperature. The condition of its control directly impacts the once-through boiler’s safety and economy running. For an uncertainty model, a good control quality can not be gained using the general PID controller when the unit load has great changes, so that the main steam temperature fluctuates greatly. According to this problem, a control system about intermediate point temperature of supercritical boiler based on active-disturbances-rejection multiple model was designed. Corresponding active disturbances rejection controller (ADRC about different model in different operation points was designed. It can choose corresponding controller according to the operation condition so as to achieve an adaptive control of a wide range. The simulation results show that the system has a strong robustness and sufficient capability for control.  

  1. Estimation of Temperature Influence on Creep Rate of High-Temperature Elements in Steam Turbines and Steam Pipelines

    Directory of Open Access Journals (Sweden)

    A. G. Gerasimova

    2011-01-01

    Full Text Available The paper considers a high temperature influence on strength characteristics of steam pipelines and steam turbine parts of high and medium pressure. The charts showing a decisive temperature importance in diffuse creep have been presented in the paper. The paper contains a calculation of steel self-diffusion coefficient. Dependence Dsd = f(t for more accurate assessment of  resource characteristics of the applied steel has been proposed in the paper.

  2. Nonuniformity of Temperatures in Microwave Steam Heating of Lobster Tail.

    Science.gov (United States)

    Fleischman, Gregory J

    2016-11-01

    The biennial Conference for Food Protection provides a formal process for all interested parties to influence food safety guidance. At a recent conference, an issue was raised culminating in a formal request to the U.S. Food and Drug Administration to change its Food Code recommendation for safe cooking of seafood using microwave energy when steaming was also employed. The request was to treat microwave steam cooked seafood as a conventionally cooked raw animal product rather than a microwave cooked product, for which the safe cooking recommendation is more extensive owing to the complex temperature distributions in microwave heating. The request was motivated by a literature study that revealed a more uniform temperature distribution in microwave steam cooked whole lobster. In that study, single-point temperatures were recorded in various sections of the whole lobster, but only one temperature was recorded in the tail, although the large size of the tail could translate to multiple hot and cold points. The present study was conducted to examine lobster tail specifically, measuring temperatures at multiple points during microwave steam cooking. Large temperature differences, greater than 60°C at times, were found throughout the heating period. To compensate for such differences, the Food Code recommends a more extensive level of cooking when microwave energy, rather than conventional heat sources, is used. Therefore, a change in the Food Code regarding microwave steam heating cannot be recommended.

  3. Neuro-fuzzy generalized predictive control of boiler steam temperature

    Institute of Scientific and Technical Information of China (English)

    Xiangjie LIU; Jizhen LIU; Ping GUAN

    2007-01-01

    Power plants are nonlinear and uncertain complex systems.Reliable control of superheated steam temperature is necessary to ensure high efficiency and high load-following capability in the operation of modern power plant.A nonlinear generalized predictive controller based on neuro-fuzzy network(NFGPC)is proposed in this paper.The proposed nonlinear controller is applied to control the superheated steam temperature of a 200MW power plant.From the experiments on the plant and the simulation of the plant,much better performance than the traditional controller is obtained.

  4. Mathematical modelling of steam generator and design of temperature regulator

    Energy Technology Data Exchange (ETDEWEB)

    Bogdanovic, S.S. [EE Institute Nikola Tesla, Belgrade (Yugoslavia)

    1999-07-01

    The paper considers mathematical modelling of once-through power station boiler and numerical algorithm for simulation of the model. Fast and numerically stable algorithm based on the linearisation of model equations and on the simultaneous solving of differential and algebraic equations is proposed. The paper also presents the design of steam temperature regulator by using the method of projective controls. Dynamic behaviour of the system closed with optimal linear quadratic regulator is taken as the reference system. The desired proprieties of the reference system are retained and solutions for superheated steam temperature regulator are determined. (author)

  5. Engineering solutions related to the furnace arrangement of a boiler designed for operating at supercritical steam conditions

    Science.gov (United States)

    Shtegman, A. V.; Ryzhii, I. A.; Sosin, D. V.; Kotler, V. R.

    2014-04-01

    When developing a coal-fired power unit designed for operating at supercritical steam conditions (SSCs), it is necessary not only to achieve high economic performance and the high reliability of a new power unit, but also to tackle many problems related to the efficient combustion of the solid fuel without exceeding the future standards for limitations on emissions of harmful substances into the atmosphere. The technological methods of suppression of nitrogen oxides capable of providing the permissible NO x emissions are discussed. The results of calculations are given that demonstrate the feasibility of achieving the purpose in view by means of installation of new low-NO x burners and staged injection of the fuel even on combustion of the Ekibastuz black coal high in ash content.

  6. Liquid Fuel Production from Biomass via High Temperature Steam Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Grant L. Hawkes; Michael G. McKellar

    2009-11-01

    A process model of syngas production using high temperature electrolysis and biomass gasification is presented. Process heat from the biomass gasifier is used to heat steam for the hydrogen production via the high temperature steam electrolysis process. Hydrogen from electrolysis allows a high utilization of the biomass carbon for syngas production. Oxygen produced form the electrolysis process is used to control the oxidation rate in the oxygen-fed biomass gasifier. Based on the gasifier temperature, 94% to 95% of the carbon in the biomass becomes carbon monoxide in the syngas (carbon monoxide and hydrogen). Assuming the thermal efficiency of the power cycle for electricity generation is 50%, (as expected from GEN IV nuclear reactors), the syngas production efficiency ranges from 70% to 73% as the gasifier temperature decreases from 1900 K to 1500 K. Parametric studies of system pressure, biomass moisture content and low temperature alkaline electrolysis are also presented.

  7. 700℃以上超超临界汽轮机高中压转子用材研究%Research on the Materials of HP and MP Rotor of More than 700℃Ultra-supercritical Steam Turbine

    Institute of Scientific and Technical Information of China (English)

    彭建强

    2013-01-01

    综合国外700℃以上汽轮机高中压转子材料研究情况,结合我国高温合金材料的发展水平,给出我国700℃以上超超临界汽轮机高中压转子用材建议。%Integrated with domestic and international research situation on HP and MP rotor of more than 700℃steam turbine , and combined with the development level of high temperature alloy materials in China , the suggestion are given for the material of HP and MP rotor of more than 700℃ultra-supercritical steam turbine in China .

  8. Research on Key Technology of Supercritical Steam Turbine%超临界汽轮机研制的关键技术及解决策略研究

    Institute of Scientific and Technical Information of China (English)

    杨其国

    2011-01-01

    针对超临界汽轮机蒸汽参数高的运行特点,指出了汽轮机零部件高温安全问题、固体颗粒腐蚀、汽流激振以及对机组效率的更高要求等关键难点.通过开发高温材料,采用转子冷却、防汽流激振和同体颗粒腐蚀等设计技术.设计制造了超临界汽轮机,圆满地解决了以上难题,在实际运行中安全高效.也为我国自主开发更高等级机组打下坚实基础.%According to the high steam parameter of supercritical steam turbine in running, this paper indicates a series of key difficulties, such as safety of parts in high temperature condition, solid particles erosion , steam excited vibration,more higher efficiency, etc. These difficulties above were solved successfully by technologies of high temperature materials,rotor cooling, protection against steam excited vibration and solid particles erosion. This power unit has high safety and efficiency in working, lays a solid foundation for development of high parameters units by self-research in China.

  9. 600 MW超临界机组汽温控制策略研究%Control Strategies of Steam Temperature in 600MW Supercriticai Units

    Institute of Scientific and Technical Information of China (English)

    方廷璋; 刘立伟; 吴延龙

    2009-01-01

    The 600MW supercritical once-through boiler units are introduced and the control strategies for the main steam temperature and reheat steam temperature are designed. Two-stage spray desuperheating control method, including the two-loop and cascade control strategies, is designed for the main steam temperature. The reheat steam temperature is controlled by regulating gas baffle and spray desuperheating auxiliarily. Operation experiences of the units indicate that the system operates well and the temperature control strategies of the main steam and reheat steam is effective.%针对某600Mw超临界直流锅炉机组,设计了机组的主汽温和再热汽温控制策略.主汽温采用二级喷水减温控制,同时设计了双回路和串级控制策略;再热汽温主要采用烟气挡板调节,辅助采用喷水减温控制.运行实践表明,机组运行稳定,主汽温和再热汽温控制策略有效.

  10. Improved phenol adsorption on carbons after mild temperature steam reactivation.

    Science.gov (United States)

    Cabal, B; Tsyntsarski, B; Budinova, T; Petrov, N; Parra, J B; Ania, C O

    2009-07-30

    The purpose of this work is to explore steam reactivation at moderate temperatures of activated carbon exhausted with phenol, a highly toxic compound frequently present in industrial wastewater. The spent carbon was treated with steam at various temperatures (450, 600 and 850 degrees C) and times (from 5 to 60 min). Promising results were obtained by applying moderate temperatures and times. Whereas at low temperatures the complete regeneration of the carbon is not accomplished, an almost quantitative desorption of the pollutant was achieved at 600 degrees C after exposure times below 30 min, with minimal damages in the porous network of the carbon. Further reutilization of the regenerated carbon resulted in a superior performance towards phenol uptake. The regeneration efficiency at 850 degrees C strongly depends on the time of reactivation, with an enhanced phenol uptake when short treatment times are applied. Prolonged duration of the regeneration treatment reduced phenol adsorption capacities, due to overreactivation of the carbon in the steam atmosphere, and to the blockage of the porous carbon network.

  11. Improved Sterilization of Sensitive Biomaterials with Supercritical Carbon Dioxide at Low Temperature.

    Directory of Open Access Journals (Sweden)

    Anne Bernhardt

    Full Text Available The development of bio-resorbable implant materials is rapidly going on. Sterilization of those materials is inevitable to assure the hygienic requirements for critical medical devices according to the medical device directive (MDD, 93/42/EG. Biopolymer-containing biomaterials are often highly sensitive towards classical sterilization procedures like steam, ethylene oxide treatment or gamma irradiation. Supercritical CO₂ (scCO₂ treatment is a promising strategy for the terminal sterilization of sensitive biomaterials at low temperature. In combination with low amounts of additives scCO₂ treatment effectively inactivates microorganisms including bacterial spores. We established a scCO₂ sterilization procedure under addition of 0.25% water, 0.15% hydrogen peroxide and 0.5% acetic anhydride. The procedure was successfully tested for the inactivation of a wide panel of microorganisms including endospores of different bacterial species, vegetative cells of gram positive and negative bacteria including mycobacteria, fungi including yeast, and bacteriophages. For robust testing of the sterilization effect with regard to later application of implant materials sterilization all microorganisms were embedded in alginate/agarose cylinders that were used as Process Challenge Devices (PCD. These PCD served as surrogate models for bioresorbable 3D scaffolds. Furthermore, the impact of scCO₂ sterilization on mechanical properties of polysaccharide-based hydrogels and collagen-based scaffolds was analyzed. The procedure was shown to be less compromising on mechanical and rheological properties compared to established low-temperature sterilization methods like gamma irradiation and ethylene oxide exposure as well as conventional steam sterilization. Cytocompatibility of alginate gels and scaffolds from mineralized collagen was compared after sterilization with ethylene oxide, gamma irradiation, steam sterilization and scCO₂ treatment. Human

  12. Corrosion of Candidate High Temperature Alloys in Supercritical Carbon Dioxide

    Science.gov (United States)

    Parks, Curtis J.

    The corrosion resistance of three candidate alloys is tested in supercritical carbon dioxide (S-CO2) at different levels of temperature and pressure for up to 3000 hours. The purpose of the testing is to evaluate the compatibility of different engineering alloys in S-CO2 for use in a S-CO 2 Brayton cycle. The three alloys used are austenitic stainless steel 316, iron-nickel-base superalloy 718, and nickel-base superalloy 738. Each alloy is exposed to four combinations of temperature and pressure, consisting of either 550°C or 700°C at either 15 or 25 MPa for up to 1500 hours. At each temperature, an additional sample set is tested for 3000 hours and experienced an increase in pressure from 15 MPa to 25 MPa after 1500 hours of testing. All three alloys are successful in producing a protective oxide layer at the lower temperature of 550°C based on the logarithmic weight gain trends. At the higher temperature of 700°C, 316SS exhibits unfavourable linear weight gain trends at both pressures of 15 and 25 MPa. In comparison, IN-718 and IN-738 performs similarly in producing a protective oxide layer illustrated through a power weight gain relation. The effect of pressure is most pronounced at the operating temperature of 700°C, where the higher pressure of 25 MPa results in an increased rate of oxide formation. SEM analysis exposes a thin film oxide for both IN-718 and IN-738 but severe intergranular corrosion is exhibited by IN-738. Based on the testing conducted, both alloys show favourable characteristics for use in S-CO 2 conditions up to 700°C, but further testing is required to characterize the effect of the intergranular corrosion on the stability of oxide in IN-738. 316SS provided favourable results for use in temperatures of 550°C, but the protective oxide deteriorated at an operating temperature of 700°C.

  13. Co-Fe-Si Aerogel Catalytic Honeycombs for Low Temperature Ethanol Steam Reforming

    Directory of Open Access Journals (Sweden)

    Montserrat Domínguez

    2012-09-01

    Full Text Available Cobalt talc doped with iron (Fe/Co~0.1 and dispersed in SiO2 aerogel was prepared from silica alcogel impregnated with metal nitrates by supercritical drying. Catalytic honeycombs were prepared following the same procedure, with the alcogel synthesized directly over cordierite honeycomb pieces. The composite aerogel catalyst was characterized by X-ray diffraction, scanning electron microscopy, focus ion beam, specific surface area and X-ray photoelectron spectroscopy. The catalytic layer is about 8 µm thick and adheres well to the cordierite support. It is constituted of talc layers of about 1.5 µm × 300 nm × 50 nm which are well dispersed and anchored in a SiO2 aerogel matrix with excellent mass-transfer properties. The catalyst was tested in the ethanol steam reforming reaction, aimed at producing hydrogen for on-board, on-demand applications at moderate temperature (573–673 K and pressure (1–7 bar. Compared to non-promoted cobalt talc, the catalyst doped with iron produces less methane as byproduct, which can only be reformed at high temperature, thereby resulting in higher hydrogen yields. At 673 K and 2 bar, 1.04 NLH2·mLEtOH(l−1·min−1 are obtained at S/C = 3 and W/F = 390 g·min·molEtOH−1.

  14. Low Temperature Synthesis of Metal Oxides by a Supercritical Seed Enhanced Crystallization (SSEC) Process

    DEFF Research Database (Denmark)

    Jensen, Henrik; Brummerstedt Iversen, Steen; Joensen, Karsten Dan

    2006-01-01

    A novel method for producing crystalline nanosized metal oxides by a Supercritical Seed Enhanced Crystallization (SSEC) Process has been developed. The process is a modified sol-gel process taking place at temperatures as low as 95 ºC with supercritical CO2 as solvent and polypropylene as seeding....... The crystallinity can be controlled by changing the heating rate of the initial formation of the nanoparticles and the morphology can be altered by changing the process time....

  15. Thermosyphon Method for Cooling the Rotor Blades of High-Temperature Steam Turbines

    Directory of Open Access Journals (Sweden)

    Bogomolov Alexander R.

    2016-01-01

    Full Text Available The design scheme of closed two-phase thermosyphon were suggested that can provide standard thermal operation of blades of high-temperature steam turbine. The method for thermosyphon calculation is developed. The example of thermal calculation was implemented, it showed that to cool the steam turbine blades at their heating by high-temperature steam, the heat can be removed in the rear part of the blades by air with the temperature of about 440°C.

  16. Thermosyphon Method for Cooling the Rotor Blades of High-Temperature Steam Turbines

    Science.gov (United States)

    Bogomolov, Alexander R.; Temnikova, Elena Yu.

    2016-02-01

    The design scheme of closed two-phase thermosyphon were suggested that can provide standard thermal operation of blades of high-temperature steam turbine. The method for thermosyphon calculation is developed. The example of thermal calculation was implemented, it showed that to cool the steam turbine blades at their heating by high-temperature steam, the heat can be removed in the rear part of the blades by air with the temperature of about 440°C.

  17. Thermosyphon Method for Cooling the Rotor Blades of High-Temperature Steam Turbines

    OpenAIRE

    Bogomolov Alexander R.; Temnikova Elena Yu.

    2016-01-01

    The design scheme of closed two-phase thermosyphon were suggested that can provide standard thermal operation of blades of high-temperature steam turbine. The method for thermosyphon calculation is developed. The example of thermal calculation was implemented, it showed that to cool the steam turbine blades at their heating by high-temperature steam, the heat can be removed in the rear part of the blades by air with the temperature of about 440°C.

  18. [Analyze on chemical compositions of Dalbergia odorifera essential oils extracted by CO2-supercritical-fluid-extraction and steam distillation extraction].

    Science.gov (United States)

    Song, Wei-Feng; Liao, Mei-Jin; Luo, Shu-Yuan

    2011-11-01

    To analyze the chemical compositions of Dalbergia odorifera essential oils extacted by CO2-supercritical-fluid-extraction (SFE-CO2) and steam distillation extraction (SD). The essential oils of Dalbergia odorifera were extracted by steam distillation extraction and SFE-CO2. The chemical components were separated and analyzed by gas chromatography-mass spectrometry. 12 compounds were identified in SFE sample. The major components from essential oils were 2-propenoic acid-3(4-methoxyphenyl)-ethyl ester (14.53%), nerolidol (14.95%), ageratochromene (1.33%). 9 compounds were identified in SD sample. The major components from essential oils were nerolidol (26.61%), cedrol (1.65%). The SFE method is better than the SD method in reliability stability and reproducibility, and suitable for essential oils extraction of Dalbergia odorifera.

  19. Bio-Fuel Production Assisted with High Temperature Steam Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Grant Hawkes; James O' Brien; Michael McKellar

    2012-06-01

    Two hybrid energy processes that enable production of synthetic liquid fuels that are compatible with the existing conventional liquid transportation fuels infrastructure are presented. Using biomass as a renewable carbon source, and supplemental hydrogen from high-temperature steam electrolysis (HTSE), these two hybrid energy processes have the potential to provide a significant alternative petroleum source that could reduce dependence on imported oil. The first process discusses a hydropyrolysis unit with hydrogen addition from HTSE. Non-food biomass is pyrolyzed and converted to pyrolysis oil. The pyrolysis oil is upgraded with hydrogen addition from HTSE. This addition of hydrogen deoxygenates the pyrolysis oil and increases the pH to a tolerable level for transportation. The final product is synthetic crude that could then be transported to a refinery and input into the already used transportation fuel infrastructure. The second process discusses a process named Bio-Syntrolysis. The Bio-Syntrolysis process combines hydrogen from HTSE with CO from an oxygen-blown biomass gasifier that yields syngas to be used as a feedstock for synthesis of liquid synthetic crude. Conversion of syngas to liquid synthetic crude, using a biomass-based carbon source, expands the application of renewable energy beyond the grid to include transportation fuels. It can also contribute to grid stability associated with non-dispatchable power generation. The use of supplemental hydrogen from HTSE enables greater than 90% utilization of the biomass carbon content which is about 2.5 times higher than carbon utilization associated with traditional cellulosic ethanol production. If the electrical power source needed for HTSE is based on nuclear or renewable energy, the process is carbon neutral. INL has demonstrated improved biomass processing prior to gasification. Recyclable biomass in the form of crop residue or energy crops would serve as the feedstock for this process. A process model

  20. Bio-Fuel Production Assisted with High Temperature Steam Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Grant Hawkes; James O' Brien; Michael McKellar

    2012-06-01

    Two hybrid energy processes that enable production of synthetic liquid fuels that are compatible with the existing conventional liquid transportation fuels infrastructure are presented. Using biomass as a renewable carbon source, and supplemental hydrogen from high-temperature steam electrolysis (HTSE), these two hybrid energy processes have the potential to provide a significant alternative petroleum source that could reduce dependence on imported oil. The first process discusses a hydropyrolysis unit with hydrogen addition from HTSE. Non-food biomass is pyrolyzed and converted to pyrolysis oil. The pyrolysis oil is upgraded with hydrogen addition from HTSE. This addition of hydrogen deoxygenates the pyrolysis oil and increases the pH to a tolerable level for transportation. The final product is synthetic crude that could then be transported to a refinery and input into the already used transportation fuel infrastructure. The second process discusses a process named Bio-Syntrolysis. The Bio-Syntrolysis process combines hydrogen from HTSE with CO from an oxygen-blown biomass gasifier that yields syngas to be used as a feedstock for synthesis of liquid synthetic crude. Conversion of syngas to liquid synthetic crude, using a biomass-based carbon source, expands the application of renewable energy beyond the grid to include transportation fuels. It can also contribute to grid stability associated with non-dispatchable power generation. The use of supplemental hydrogen from HTSE enables greater than 90% utilization of the biomass carbon content which is about 2.5 times higher than carbon utilization associated with traditional cellulosic ethanol production. If the electrical power source needed for HTSE is based on nuclear or renewable energy, the process is carbon neutral. INL has demonstrated improved biomass processing prior to gasification. Recyclable biomass in the form of crop residue or energy crops would serve as the feedstock for this process. A process model

  1. Molybdenum Disilicide Oxidation Kinetics in High Temperature Steam

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Elizabeth Sooby [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parker, Stephen Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nelson, Andrew Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-07

    The Fuel Cycle Research and Development program’s Advanced Fuels Campaign is currently supporting a range of experimental efforts aimed at the development and qualification of ‘accident tolerant’ nuclear fuel forms. One route to enhance the accident tolerance of nuclear fuel is to replace the zirconium alloy cladding, which is prone to rapid oxidation in steam at elevated temperatures, with a more oxidation resistant cladding. Several cladding replacement solutions have been envisaged. The cladding can be completely replaced with a more oxidation resistant alloy, a layered approach can be used to optimize the strength, creep resistance, and oxidation tolerance of various materials, or the existing zirconium alloy cladding can be coated with a more oxidation resistant material. Molybdenum is one candidate cladding material favored due to its high temperature creep resistance. However, it performs poorly under autoclave testing and suffers degradation under high temperature steam oxidation exposure. Development of composite cladding architectures consisting of a molybdenum core shielded by a molybdenum disilicide (MoSi2) coating is hypothesized to improve the performance of a Mo-based cladding system. MoSi2 was identified based on its high temperature oxidation resistance in O2 atmospheres (e.g. air and “wet air”). However, its behavior in H2O is less known. This report presents thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and x-ray diffraction (XRD) results for MoSi2 exposed to 670-1498 K water vapor. Synthetic air (80-20%, Ar-O2) exposures were also performed and those results are presented here for a comparative analysis. It was determined that MoSi2 displays drastically different oxidation behavior in water vapor than in dry air. In the 670-1498 K temperature range, four distinct behaviors are observed. Parabolic oxidation is exhibited in only 670-773 K

  2. Molybdenum Disilicide Oxidation Kinetics in High Temperature Steam

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Elizabeth Sooby [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parker, Stephen Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nelson, Andrew Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-07

    The Fuel Cycle Research and Development program’s Advanced Fuels Campaign is currently supporting a range of experimental efforts aimed at the development and qualification of ‘accident tolerant’ nuclear fuel forms. One route to enhance the accident tolerance of nuclear fuel is to replace the zirconium alloy cladding, which is prone to rapid oxidation in steam at elevated temperatures, with a more oxidation-resistant cladding. Several cladding replacement solutions have been envisaged. The cladding can be completely replaced with a more oxidation resistant alloy, a layered approach can be used to optimize the strength, creep resistance, and oxidation tolerance of various materials, or the existing zirconium alloy cladding can be coated with a more oxidation-resistant material. Molybdenum is one candidate cladding material favored due to its high temperature creep resistance. However, it performs poorly under autoclave testing and suffers degradation under high temperature steam oxidation exposure. Development of composite cladding architectures consisting of a molybdenum core shielded by a molybdenum disilicide (MoSi2) coating is hypothesized to improve the performance of a Mo-based cladding system. MoSi2 was identified based on its high temperature oxidation resistance in O2 atmospheres (e.g. air and “wet air”). However, its behavior in H2O is less known. This report presents thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and x-ray diffraction (XRD) results for MoSi2 exposed to 670-1498 K water vapor. Synthetic air (80-20%, Ar-O2) exposures were also performed, and those results are presented here for a comparative analysis. It was determined that MoSi2 displays drastically different oxidation behavior in water vapor than in dry air. In the 670-1498 K temperature range, four distinct behaviors are observed. Parabolic oxidation is exhibited in only 670

  3. Chemical compositions and antioxidant properties of essential oils from nine species of Turkish plants obtained by supercritical carbon dioxide extraction and steam distillation.

    Science.gov (United States)

    Topal, Ummihan; Sasaki, Mitsuru; Goto, Motonobu; Otles, Semih

    2008-01-01

    Chemical compositions and antioxidant activities of essential oils from nine different species of Turkish plants, namely Melissa officinalis L., Rosmarinus officinalis L., Cuminum cyminum L., Piper nigrum L., Lavandula stoechas spp., Foeniculum vulgare, Pimpinella anisum L., Thymus serpyllum and Liquidamber orientalis Mill., were studied. Essential oils were obtained by supercritical carbon dioxide (SCCO2) extraction and steam distillation, and were analyzed by gas chromatography-mass spectrometry. The antioxidant activities of SCCO2 extraction and steam distillation extracts were tested by means of the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Essential oils extracted by SCCO2 and steam distillation showed different compositions in different species. In the DPPH assay, R. officinalis, C. cyminum, P. anisum, T. serpyllum and L. orientalis essential oils obtained by SCCO2 extraction showed higher antioxidant activity than steam distillation extracts, with radical scavenging activities ranging from 87.1 +/- 0.23% to 92.0 +/- 0.34% compared with the butylated hydroxytoluene positive control (91.4 +/- 0.21%).

  4. Corrosion behaviour of construction materials for high temperature steam electrolysers

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Petrushina, Irina; Christensen, Erik;

    2011-01-01

    Different types of commercially available stainless steels, Ni-based alloys as well as titanium and tantalum were evaluated as possible metallic bipolar plates and construction materials. The corrosion resistance was measured under simulated conditions corresponding to the conditions in high...... to corrosion under strong anodic polarisation. Among alloys, Ni-based showed the highest corrosion resistance in the simulated PEM electrolyser medium. In particular, Inconel 625 was the most promising among the tested corrosion-resistant alloys for the anodic compartment in high temperature steam electrolysis....... Tantalum showed outstanding resistance to corrosion in selected media. On the contrary, passivation of titanium was weak, and the highest rate of corrosion among all tested materials was observed for titanium at 120 degrees C....

  5. Numerical Simulation Study on IP Rotor Coding Coupled Heat Transfer of 1000MW Ultra-supercritical Steam Turbine%1000MW超超临界汽轮机中压转子冷却耦合换热数值模拟研究

    Institute of Scientific and Technical Information of China (English)

    杨明; 李长宝; 管继伟; 刘云峰

    2013-01-01

    By using CFD and conjugate heat transfer(CHT) methods,IP Rotor Cooling of 1000MW Ultra-supercritical Steam Turbine has been numerical simulated.The temperature distribution whether the fluid and solid coupled heat transfer,cooling steam temperature effects on IP Rotor and the temperature distribution of the two half-rotor have been investigated.The fluid and solid temperature field distribution characteristics has been more realistic simulated.This article can provide a reliable basis for the structural design of ultra-supercritical steam turbine.%通过采用CFD和CHT(共轭换热)的数值方法,对超超临界1000MW汽轮机中压转子冷却进行了数值模拟,研究了有无流体与固体耦合换热的温度场分布差别,冷却蒸汽温度对中压转子冷却效果的影响,中压二级半转子冷却的温度分布,较真实地模拟了流体、固体区域温度场的分布特性.

  6. Primary collector wall local temperature fluctuations in the area of water-steam phase boundary

    Energy Technology Data Exchange (ETDEWEB)

    Matal, O.; Klinga, J.; Simo, T. [Energovyzkum Ltd., Brno (Switzerland)

    1995-12-31

    A limited number of temperature sensors could be installed at the primary collector surface in the area of water - steam phase boundary. The surface temperatures as well WWER 440 steam generator process data were measured and stored for a long time and off-line evaluated. Selected results are presented in the paper. (orig.). 2 refs.

  7. Interpretation of Temperature Profiles during Soak Periods in Steam-stimulated Wells

    Institute of Scientific and Technical Information of China (English)

    Liu Huiqing; Zhang Hongling; Wang Peixi

    2007-01-01

    To address the problems existing in testing steam injection profiles in a steam-stimulated well during steam injection and production periods, this paper proposes that the temperature profile in the completion interval could be tested during the soak period. A mathematical model for calculating the vertical distribution of temperature in a single layer reservoir is established based on the temperature characteristics of steam stimulated reservoirs, and the vertical distribution of temperature in a single layer reservoir could be obtained and heat loss could be calculated.The temperature, which is disturbed by thermal conduction in a multilayer reservoir, and heat loss could be derived based on the superposition principle of temperature potential. This paper establishes a multilayer testing temperature profile interpretation method and interprets the actual test temperature profile of Well Gao 3-7-66. The results indicate that the temperature profile in the soak period can reflect the thermal absorption conditions in various reservoir beds.

  8. Effects of injection temperature on the jet evolution under supercritical conditions

    Institute of Scientific and Technical Information of China (English)

    YIN YanMei; LU XiYun

    2009-01-01

    A nitrogen jet with subcritical and supercritical injection temperatures injected into a supercritical environment,in which both the pressure and temperature exceed those of the thermodynamic critical state,has been investigated numerically using large-eddy simulation technique.The effects of the injection temperature on the flow evolution are studied.We find that the jet surface is more unstable with the instability waves growing up and rolling into a succession of ring vortices for supercritical injection temperature,and the jet surface is nearly straight with the strong density stratification suppressing the development of the instability waves for subcritical injection temperature.With increasing injection temperature,the spatial growth rate of the surface instability wave strengthens and the frequency of the most unstable mode increases.This behavior is of importance in enhancing the fluid mixing effect.The results obtained in this study provide physical insight into the understanding of fundamental mechanisms of the jet evolution under supercritical conditions.

  9. Enrichment of vanillin in barley malt by hydrolysis in high temperature and high pressure steam.

    Science.gov (United States)

    Nakahara, Koichi; Kageyama, Norihiko; Nagami, Kenzo

    2012-12-19

    Malted barley was treated with saturated steam at temperatures ranging from 180 to 220 °C, that is, high temperature and high pressure steam (HHS), and a control sample exposed to saturated liquid water in the same temperature range. The malt treated in steam was extracted with water (70 °C) for 15 min after drying. Vanillin which gave beer preferable flavor was detected in all malt extracts, both after treatment with steam and in effluent from malt exposed to liquid water. Hydrolysis of ingredients in the malt occurred even in steam. The treatment of natural products in HHS could be a new thermal technique to provide a special ingredient for food industry, for example, malt for beer.

  10. 汽轮机喷嘴室温度场分析%Analysis of the Temperature Field of Steam Turbine Nozzle Chamber

    Institute of Scientific and Technical Information of China (English)

    王林; 程荣新; 张宏涛; 李宇峰; 翁振宇

    2015-01-01

    Nozzle chamber is one of the key components in steam turbine , the analysis of the temperature field is important when nozzle chamber of steam turbine is designed .Aim at a 600MW sub-critical steam turbine nozzle chamber , a three-dimensional finite element model of the nozzle chamber is developed , methods for calculating the convective heat transfer coefficients of the nozzle chamber surfaces different regions are described , three-dimensional transient thermal analysis is performed on the nozzle chamber by using finite element method .Detailed temperature distributions are determined during the cold start transient operating conditions .The results show that temperature distributions of the active chambers and those of the inactive chambers are different , inner surface temperature is higher than other surfaces temperature for the active chambers, temperatures of the contact surfaces between the inner casing and the support lugs on the nozzle chamber are lowest.The used analytic methods can be applied for temperature field analysis of sub-critical, supercritical and ultra-supercritical steam turbine nozzle chamber , a basis for the cooling design and the life evaluation of steam turbine nozzle chamber is provided .%喷嘴室是汽轮机中的关键部件,在汽轮机喷嘴室的设计过程中,必须分析其温度场。针对某亚临界600MW汽轮机喷嘴室,建立了三维有限元模型,介绍了喷嘴室表面不同区域的对流换热系数计算方法,用有限元法分析了喷嘴室的三维瞬态温度场,得出了在冷态启动运行工况的详细温度分布。结果表明,喷嘴室开启的室和关闭的室温度分布不同,对于开启的室,内表面的温度明显高于其它表面,内缸和喷嘴室支承键的接触表面处温度最低。所采用的分析方法可以用于分析亚临界、超临界和超超临界汽轮机喷嘴室,为喷嘴室的冷却设计和寿命评估打下了基础。

  11. Analysis of Precooling Injection Transient of Steam Generator for High Temperature Gas Cooled Reactor

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2017-01-01

    Full Text Available After a postulated design basis accident leads high temperature gas cooled reactor to emergency shutdown, steam generator still remains with high temperature level and needs to be cooled down by a precooling before reactor restarts with clearing of fault. For the large difference of coolant temperature between inlet and outlet of steam generator in normal operation, the temperature distribution on the components of steam generator is very complicated. Therefore, the temperature descending rate of the components in steam generator needs to be limited to avoid the potential damage during the precooling stage. In this paper, a pebble-bed high temperature gas cooled reactor is modeled by thermal-hydraulic system analysis code and several postulated precooling injection transients are simulated and compared to evaluate their effects, which will provide support for the precooling design. The analysis results show that enough precooling injection is necessary to satisfy the precooling requirements, and larger mass flow rate of precooling water injection will accelerate the precooling process. The temperature decrease of steam generator is related to the precooling injection scenarios, and the maximal mass flow rate of the precooling injection should be limited to avoid the excessively quick temperature change of the structures in steam generator.

  12. [Comparison of Chemical Components of Essential Oil from Ocimum basilicum var. pilosum Extracted by Supercritical CO2 Fluid and Steam Distillation].

    Science.gov (United States)

    Wang, Zhao-yu; Zheng, Jia-huan; Shi, Sheng-ying; Luo, Zhi-xiong; Ni, Shun-yu; Lin, Jing-ming

    2015-11-01

    To compare the chemical components of essential oil prepared by steam distillation extraction (SD) and supercritical CO2 fluid extraction (SFE-CO2) from Ocimum basilicum var. pilosum whole plant. The essential oil of Ocimum basilicum var. pilosum were extracted by SD and SFE-CO2. The chemical components of essential oil were separated and analyzed by gas chromatography-mass spectrometry( GC-MS). Their relative contents were determined by normalization of peak area. 40 and 42 compounds were detected in the essential oil prepared by SD and SFE-CO2 respectively. 25 compounds were common. Thereare significant differences of the chemical components between the Ocimum basilicum var. pilosum essential oil prepared by SD and thatby SFE-CO2. Different methods showed different extraction efficiency with a special compound. It might be a good idea to unite several methods in the modern traditional Chinese medicine industry.

  13. Hydrogen absorption in solid aluminum during high-temperature steam oxidation

    Science.gov (United States)

    Andreev, L. A.; Gelman, B. G.; Zhukhovitskiy, A. A.

    1979-01-01

    Hydrogen is emitted by aluminum heated in a vacuum after high-temperature steam treatment. Wire samples are tested for this effect, showing dependence on surface area. Two different mechanisms of absorption are inferred, and reactions deduced.

  14. Supercritical boiler material selection using fuzzy analytic network process

    Directory of Open Access Journals (Sweden)

    Saikat Ranjan Maity

    2012-08-01

    Full Text Available The recent development of world is being adversely affected by the scarcity of power and energy. To survive in the next generation, it is thus necessary to explore the non-conventional energy sources and efficiently consume the available sources. For efficient exploitation of the existing energy sources, a great scope lies in the use of Rankin cycle-based thermal power plants. Today, the gross efficiency of Rankin cycle-based thermal power plants is less than 28% which has been increased up to 40% with reheating and regenerative cycles. But, it can be further improved up to 47% by using supercritical power plant technology. Supercritical power plants use supercritical boilers which are able to withstand a very high temperature (650-720˚C and pressure (22.1 MPa while producing superheated steam. The thermal efficiency of a supercritical boiler greatly depends on the material of its different components. The supercritical boiler material should possess high creep rupture strength, high thermal conductivity, low thermal expansion, high specific heat and very high temperature withstandability. This paper considers a list of seven supercritical boiler materials whose performance is evaluated based on seven pivotal criteria. Given the intricacy and difficulty of this supercritical boiler material selection problem having interactions and interdependencies between different criteria, this paper applies fuzzy analytic network process to select the most appropriate material for a supercritical boiler. Rene 41 is the best supercritical boiler material, whereas, Haynes 230 is the worst preferred choice.

  15. Low-temperature, selective catalytic deoxygenation of vegetable oil in supercritical fluid media.

    Science.gov (United States)

    Kim, Seok Ki; Lee, Hong-Shik; Hong, Moon Hyun; Lim, Jong Sung; Kim, Jaehoon

    2014-02-01

    The effects of supercritical fluids on the production of renewable diesel-range hydrocarbons from natural triglycerides were investigated. Various supercritical fluids, which included CO2 (scCO2 ), propane (scC3 H8 ) and n-hexane (scC6 H14 ), were introduced with H2 and soybean oil into a fixed-bed reactor that contained pre-activated CoMo/γ-Al2 O3 . Among these supercritical fluids, scC3 H8 and scC6 H14 efficiently allowed the reduction of the reaction temperature by as much as 50 °C as a result of facilitated heat and mass transfer and afforded similar yields to reactions in the absence of supercritical fluids. The compositional analyses of the gas and liquid products indicated that the addition of scC3 H8 during the hydrotreatment of soybean oil promoted specific deoxygenation pathways, decarbonylation and decarboxylation, which consumed less H2 than the hydrodeoxygenation pathway. As a result, the quantity of H2 required to obtain a high yield of diesel-range hydrocarbons could be reduced to 57 % if scC3 H8 was used. As decarboxylation and decarbonylation are mildly endothermic reactions, the reduced heat transfer resistance in scC3 H8 may drive the deoxygenation reaction to thermodynamically favourable pathways.

  16. Inactivation of Mold Spores from Moist Carpet Using Steam Vapor: Contact Time and Temperature.

    Science.gov (United States)

    Ong, Kee-Hean; Emo, Brett; Lewis, Roger D; Kennedy, Jason; Thummalakunta, Laxmi N A; Elliott, Michael

    2015-01-01

    Steam vapor has been shown to reduce viable mold spores in carpet, but the minimal effective temperature and contact time has not been established. This study evaluated the effectiveness of steam vapor in reducing the number of viable mold spores in carpet as a function of temperature and contact time. Seventy carpet samples were inoculated with a liquid suspension of Cladosporium sphaerospermum and incubated over a water-saturated foam carpet pad for 24 hr. Steam was applied to the samples as the temperature was measured from the carpet backing. Contact time was closely monitored over seven time intervals: 0, 2, 4, 8, 12, 16, and 20 sec. Following steam vapor treatment, mold spores were extracted from the carpet samples and the extract was plated on DG-18 plates at 1:1, 1:10, 1:100 dilutions followed by one week of incubation. Raw colony forming units were determined using an automated colony counter and adjusted based on dilution factor, extraction volume, and plated volume. Analysis of variance and linear regression were used to test for statistically significant relationships. Steam contact time exhibited a linear relationship to observed temperature of carpet backing (F = 90.176, R(2) = 0.609). Observed temperature of carpet backing had a positive relationship to percent reduction of mold (F = 76.605, R(2) = 0.569). Twelve seconds of steam vapor contact time was needed to achieve over 90% mold reduction on moist carpet.

  17. Analysis of prompt supercritical process with heat transfer and temperature feedback

    Institute of Scientific and Technical Information of China (English)

    ZHU BO; ZHU Qian; CHEN Zhiyun

    2009-01-01

    The prompt supercritical process of a nuclear reactor with temperature feedback and initial power as well as heat transfer with a big step reactivity (ρ0>β) is analyzed in this paper.Considering the effect of heat transfer on temperature of the reactor,a new model is set up.For any initial power,the variations of output power and reactivity with time are obtained by numerical method.The effects of the big inserted step reactivity and initial power on the prompt supercritical process are analyzed and discussed.It was found that the effect of heat transfer on the output power and reactivity can be neglected under any initial power,and the output power obtained by the adiabatic model is basically in accordance with that by the model of this paper,and the analytical solution can be adopted.The results provide a theoretical base for safety analysis and operation management of a power reactor.

  18. Supercritical Water Mixture (SCWM) Experiment in the High Temperature Insert-Reflight (HTI-R)

    Science.gov (United States)

    Hicks, Michael C.; Hegde, Uday G.; Garrabos, Yves; Lecoutre, Carole; Zappoli, Bernard

    2013-01-01

    Current research on supercritical water processes on board the International Space Station (ISS) focuses on salt precipitation and transport in a test cell designed for supercritical water. This study, known as the Supercritical Water Mixture Experiment (SCWM) serves as a precursor experiment for developing a better understanding of inorganic salt precipitation and transport during supercritical water oxidation (SCWO) processes for the eventual application of this technology for waste management and resource reclamation in microgravity conditions. During typical SCWO reactions any inorganic salts present in the reactant stream will precipitate and begin to coat reactor surfaces and control mechanisms (e.g., valves) often severely impacting the systems performance. The SCWM experiment employs a Sample Cell Unit (SCU) filled with an aqueous solution of Na2SO4 0.5-w at the critical density and uses a refurbished High Temperature Insert, which was used in an earlier ISS experiment designed to study pure water at near-critical conditions. The insert, designated as the HTI-Reflight (HTI-R) will be deployed in the DECLIC (Device for the Study of Critical Liquids and Crystallization) Facility on the International Space Station (ISS). Objectives of the study include measurement of the shift in critical temperature due to the presence of the inorganic salt, assessment of the predominant mode of precipitation (i.e., heterogeneously on SCU surfaces or homogeneously in the bulk fluid), determination of the salt morphology including size and shapes of particulate clusters, and the determination of the dominant mode of transport of salt particles in the presence of an imposed temperature gradient. Initial results from the ISS experiments will be presented and compared to findings from laboratory experiments on the ground.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-15

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

  20. Creep performance of oxide ceramic fiber materials at elevated temperature in air and in steam

    Science.gov (United States)

    Armani, Clinton J.

    Structural aerospace components that operate in severe conditions, such as extreme temperatures and detrimental environments, require structural materials that have superior long-term mechanical properties and that are thermochemically stable over a broad range of service temperatures and environments. Ceramic matrix composites (CMCs) capable of excellent mechanical performance in harsh environments are prime candidates for such applications. Oxide ceramic materials have been used as constituents in CMCs. However, recent studies have shown that high-temperature mechanical performance of oxide-oxide CMCs deteriorate in a steam-rich environment. The degradation of strength at elevated temperature in steam has been attributed to the environmentally assisted subcritical crack growth in the oxide fibers. Furthermore, oxide-oxide CMCs have shown significant increases in steady-state creep rates in steam. The present research investigated the effects of steam on the high-temperature creep and monotonic tension performance of several oxide ceramic materials. Experimental facilities were designed and configured, and experimental methods were developed to explore the influence of steam on the mechanical behaviors of ceramic fiber tows and of ceramic bulk materials under temperatures in the 1100--1300°C range. The effects of steam on creep behavior of Nextel(TM)610 and Nextel(TM)720 fiber tows were examined. Creep rates at elevated temperatures in air and in steam were obtained for both types of fibers. Relationships between creep rates and applied stresses were modeled and underlying creep mechanisms were identified. For both types of fiber tows, a creep life prediction analysis was performed using linear elastic fracture mechanics and a power-law crack velocity model. These results have not been previously reported and have critical design implications for CMC components operating in steam or near the recommended design limits. Predictions were assessed and validated via

  1. Recovery of Minerals in Martian Soils Via Supercritical Fluid Extraction

    Science.gov (United States)

    Debelak, Kenneth A.; Roth, John A.

    2001-03-01

    We are investigating the use of supercritical fluids to extract mineral and/or carbonaceous material from Martian surface soils and its igneous crust. Two candidate supercritical fluids are carbon dioxide and water. The Martian atmosphere is composed mostly of carbon dioxide (approx. 95.3%) and could therefore provide an in-situ source of carbon dioxide. Water, although present in the Martian atmosphere at only approx. 0.03%, is also a candidate supercritical solvent. Previous work done with supercritical fluids has focused primarily on their solvating properties with organic compounds. Interestingly, the first work reported by Hannay and Hogarth at a meeting of the Royal Society of London in 1879 observed that increasing or decreasing the pressure caused several inorganic salts e.g., cobalt chloride, potassium iodide, and potassium bromide, to dissolve or precipitate in supercritical ethanol. In high-pressure boilers, silica, present in most boiler feed waters, is dissolved in supercritical steam and transported as dissolved silica to the turbine blades. As the pressure is reduced the silica precipitates onto the turbine blades eventually requiring the shutdown of the generator. In supercritical water oxidation processes for waste treatment, dissolved salts present a similar problem. The solubility of silicon dioxide (SiO2) in supercritical water is shown. The solubility curve has a shape characteristic of supercritical systems. At a high pressure (greater than 1750 atmospheres) increasing the temperature results in an increase in solubility of silica, while at low pressures, less than 400 atm., the solubility decreases as temperature increases. There are only a few studies in the literature where supercritical fluids are used in extractive metallurgy. Bolt modified the Mond process in which supercritical carbon monoxide was used to produce nickel carbonyl (Ni(CO)4). Tolley and Tester studied the solubility of titanium tetrachloride (TiCl4) in supercritical CO2

  2. Carbohydrate reactions during high-temperature steam treatment of aspen wood.

    Science.gov (United States)

    Li, Jiebing; Henriksson, Gunnar; Gellerstedt, Göran

    2005-06-01

    Aspen wood was treated with steam at different time-temperature severity factors. Analysis of the amounts of acids released revealed a relationship between the acidity and the formation of furfural and hydroxymethyl furfural as degradation products from carbohydrates. It is suggested that two concurrent or consecutive mechanisms are responsible for the observed results: a homolytic cleavage and an acid hydrolysis of glucosidic linkages in the polysaccharides. By preimpregnating the wood with alkali, hydrolysis can be eliminated, resulting in a much cleaner depolymerization of the polysaccharides without any further acid-catalyzed degradation. The enzymatic digestibility of the steam-treated wood material for the formation of glucose was compared with that of steam-exploded wood. A more efficient route for glucose production from steam-exploded wood was found as long as the biomass-pretreated material was homogeneous and without shives.

  3. Experimental study on pressure and temperature distributions for low mass flux steam jet in subcooled water

    Institute of Scientific and Technical Information of China (English)

    YAN JunJie; WU XinZhuang; CHONG DaoTong

    2009-01-01

    A low mass flux steam jet in subcooled water was experimentally investigated. The transition of flow pattern from stable jet to condensation oscillation was observed at relatively high water temperature. The axial total pressures, the axial and radial temperature distributions were measured in the jet region. The results indicated that the pressure and temperature distributions were mainly influenced by the water temperature. The correlations corrected with water temperature were given to predict the dimen-sionless axial pressure peak distance and axial temperature distributions in the jet region, the results showed s good agreement between the predictions and experiments. Moreover, the self-similarity property of the radial temperature was obtained, which agreed well with Gauss distribution. In present work, all the dimensionless properties were mainly dependent on the water temperature but weakly on the nozzle size under a certain steam mass flux.

  4. Molecular dynamic simulations of iron (II) hydroxide in high temperature and supercritical water

    Science.gov (United States)

    Meng, Yuanliang

    In this study, the iron (II) hydroxide -- water system has been investigated at high temperatures by using molecular dynamics (MD) simulations. The simulation results reveal that at infinite dilution both Fe2+ cation and OH- anion have 6 water molecules within their first hydration shell and both types of ionic species experience a dramatic increase in their diffusion coefficients at near and supercritical conditions. The process of iron (II) hydroxide cluster formation has been simulated. The nano-clusters of larger sizes formed in supercritical water tend to be in an amorphous state. After having been quenched by an inert gas bath, iron (II) hydroxide nano-clusters with various structures have been produced. The geometries and associated binding energies of these species are given in detail. The vibrational spectra of iron (II) hydroxide clusters are also derived and compared with the spectrum of a bulk solid. The obtained results have a practical value for the analysis of potential corrosion products in supercritical water-cooled reactor (SCWR) which is employed in the new generation nuclear power plant design (GEN IV). This work also illustrates the process of hydrothermal synthesis of oxide nano-particles.

  5. 火电厂600MW超临界机组汽轮机胀差控制分析%Steam Turbine Differential Expansion Controlling Analysis of 600 MW Supercritical Unit in Thermal Power Plant

    Institute of Scientific and Technical Information of China (English)

    杨晨; 朱懿

    2012-01-01

    N600-24.2/566/566 supercritical steam turbine which is made by Shanghai Steam Turbine Plant, for example, importance and variation of differential expansion controlling of steam turbine, mutual relations of the rotor and stator expansion, and the most effective technical measures of controlling differential expansion in the start-up process of Phase I 2 x 600 MW supercritical steam turbine of Huangjinbu Power Generation Co.,Ltd. of State Power Grid in Jiangxi were analyzed, and had some reference values for other turbines.%以上海汽轮机厂生产的N600.24.2/566/566型超临界汽轮机为例,分析了江西国电黄金埠发电有限公司1期2台600MW超临界汽轮机启动过程中,汽轮机胀差控制的重要性、变化规律、转子和静子膨胀的相互关系以及采取的最有效的控制胀差的技术措施,对于其它汽轮机具有一定的参考价值。

  6. Thermal analysis of heat and power plant with high temperature reactor and intermediate steam cycle

    Directory of Open Access Journals (Sweden)

    Fic Adam

    2015-03-01

    Full Text Available Thermal analysis of a heat and power plant with a high temperature gas cooled nuclear reactor is presented. The main aim of the considered system is to supply a technological process with the heat at suitably high temperature level. The considered unit is also used to produce electricity. The high temperature helium cooled nuclear reactor is the primary heat source in the system, which consists of: the reactor cooling cycle, the steam cycle and the gas heat pump cycle. Helium used as a carrier in the first cycle (classic Brayton cycle, which includes the reactor, delivers heat in a steam generator to produce superheated steam with required parameters of the intermediate cycle. The intermediate cycle is provided to transport energy from the reactor installation to the process installation requiring a high temperature heat. The distance between reactor and the process installation is assumed short and negligable, or alternatively equal to 1 km in the analysis. The system is also equipped with a high temperature argon heat pump to obtain the temperature level of a heat carrier required by a high temperature process. Thus, the steam of the intermediate cycle supplies a lower heat exchanger of the heat pump, a process heat exchanger at the medium temperature level and a classical steam turbine system (Rankine cycle. The main purpose of the research was to evaluate the effectiveness of the system considered and to assess whether such a three cycle cogeneration system is reasonable. Multivariant calculations have been carried out employing the developed mathematical model. The results have been presented in a form of the energy efficiency and exergy efficiency of the system as a function of the temperature drop in the high temperature process heat exchanger and the reactor pressure.

  7. PID Controller Parameters Tuning Based-on Satisfaction for Superheated Steam Temperature of Power Station Boiler

    Directory of Open Access Journals (Sweden)

    Benxian Xiao

    2014-06-01

    Full Text Available Proposed the PID controller parameters tuning method based-on New Luus-Jaakola (NLJ algorithm and satisfaction idea. According to the different requirements of each performance index, designed the satisfaction function with fuzzy constraint attributes, and then determined the comprehensive satisfaction function for PID tuning by NLJ algorithm. Provided the steps of PID controller parameters tuning based on the NLJ algorithm and satisfaction, and applied this tuning method to the cascade control system of superheated steam temperature for Power Station Boiler. Finally the simulation and experiment results have shown the proposed method has good dynamic and static control performances for this complicated superheated steam temperature control system.

  8. A high-temperature gas-and-steam turbine plant operating on combined fuel

    Science.gov (United States)

    Klimenko, A. V.; Milman, O. O.; Shifrin, B. A.

    2015-11-01

    A high-temperature gas-steam turbine plant (GSTP) for ultrasupercritical steam conditions is proposed based on an analysis of prospects for the development of power engineering around the world and in Russia up to 2040. The performance indicators of a GSTP using steam from a coal-fired boiler with a temperature of 560-620°C with its superheating to 1000-1500°C by firing natural gas with oxygen in a mixingtype steam superheater are analyzed. The thermal process circuit and design of a GSTP for a capacity of 25 MW with the high- and intermediate-pressure high-temperature parts with the total efficiency equal to 51.7% and the natural gas utilization efficiency equal to 64-68% are developed. The principles of designing and the design arrangement of a 300 MW GSTP are developed. The effect of economic parameters (the level and ratio of prices for solid fuel and gas, and capital investments) on the net cost of electric energy is determined. The net cost of electric energy produced by the GSTP is lower than that produced by modern combined-cycle power plants in a wide variation range of these parameters. The components of a high-temperature GSTP the development of which determines the main features of such installations are pointed out: a chamber for combusting natural gas and oxygen in a mixture with steam, a vacuum device for condensing steam with a high content of nondensables, and a control system. The possibility of using domestically available gas turbine technologies for developing the GSTP's intermediate-pressure high-temperature part is pointed out. In regard of its environmental characteristics, the GSTP is more advantageous as compared with modern condensing power plants: it allows a flow of concentrated carbon dioxide to be obtained at its outlet, which can be reclaimed; in addition, this plant requires half as much consumption of fresh water.

  9. 超超临界二次再热汽轮机发展综述%Development of Ultra-supercritical Double-reheat Steam Turbine

    Institute of Scientific and Technical Information of China (English)

    王建录; 张晓东

    2016-01-01

    文章概述了汽轮机二次再热技术的发展历程,当前我国超超临界二次再热汽轮机技术研发情况,并重点介绍了我国首台超超临界二次再热汽轮机技术特点及运行情况,对未来二次再热汽轮机技术发展方向和典型机型进行了探讨。%This paper introduces the evolution of double-reheat turbine technology, the development of the ultra-supercritical double-reheat turbine technology in China,and mainly introduces the technical charateristic and operation conditions of the first ultra-super⁃critical double-reheat turbine unit made by DTC in China. The new development direction and typical models of the double-reheat steam turbine designed by DTC is discussed in this paper.

  10. Steam chemistry - interaction of chemical species with water, steam, and materials during evaporation, superheating, and condensation. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    Topics of this proceedings are: steam chemistry, supercritical water, effects of chemicals in steam (acetic acid, formic acid, phosphoric acid or other impurities); solubility and deposition, condensation processes and effect of impurities; nucleation; gas-liquid interfaces; steam treatment. (SR)

  11. High Temperature Steam Corrosion of Cladding for Nuclear Applications: Experimental

    Energy Technology Data Exchange (ETDEWEB)

    McHugh, Kevin M; Garnier, John E; Sergey Rashkeev; Michael V. Glazoff; George W. Griffith; Shannong M. Bragg-Sitton

    2013-01-01

    Stability of cladding materials under off-normal conditions is an important issue for the safe operation of light water nuclear reactors. Metals, ceramics, and metal/ceramic composites are being investigated as substitutes for traditional zirconium-based cladding. To support down-selection of these advanced materials and designs, a test apparatus was constructed to study the onset and evolution of cladding oxidation, and deformation behavior of cladding materials, under loss-of-coolant accident scenarios. Preliminary oxidation tests were conducted in dry oxygen and in saturated steam/air environments at 1000OC. Tube samples of Zr-702, Zr-702 reinforced with 1 ply of a ß-SiC CMC overbraid, and sintered a-SiC were tested. Samples were induction heated by coupling to a molybdenum susceptor inside the tubes. The deformation behavior of He-pressurized tubes of Zr-702 and SiC CMC-reinforced Zr-702, heated to rupture, was also examined.

  12. Development of an Accelerated Methodology to Study Degradation of Materials in Supercritical Water for Application in High Temperature Power Plants

    Science.gov (United States)

    Rodriguez, David

    The decreasing supply of fossil fuel sources, coupled with the increasing concentration of green house gases has placed enormous pressure to maximize the efficiency of power generation. Increasing the outlet temperature of these power plants will result in an increase in operating efficiency. By employing supercritical water as the coolant in thermal power plants (nuclear reactors and coal power plants), the plant efficiency can be increased to 50%, compared to traditional reactors which currently operate at 33%. The goal of this dissertation is to establish techniques to characterize the mechanical properties and corrosion behavior of materials exposed to supercritical water. Traditionally, these tests have been long term exposure tests spanning months. The specific goal of this dissertation is to develop a methodology for accelerated estimation of corrosion rates in supercritical water that can be sued as a screening tool to select materials for long term testing. In this study, traditional methods were used to understand the degradation of materials in supercritical water and establish a point of comparison to the first electrochemical studies performed in supercritical water. Materials studied included austenitic steels (stainless steel 304, stainless steel 316 and Nitronic 50) and nickel based alloys (Inconel 625 and 718). Surface chemistry of the oxide layer was characterized using scanning electron microscopy, X-ray diffraction, FT-IR, Raman and X-ray photoelectron spectroscopies. Stainless steel 304 was subjected to constant tensile load creep tests in water at a pressure of 27 MPa and at temperatures of 200 °C, 315 °C and supercritical water at 450 °C for 24 hours. It was determined that the creep rate for stainless steel 304 exposed to supercritical water would be unacceptable for use in service. It was observed that the formation of hematite was favored in subcritical temperatures, while magnetite was formed in the supercritical region. Corrosion of

  13. Practical development of continuous supercritical fluid process using high pressure and high temperature micromixer

    Science.gov (United States)

    Kawasaki, Shin-Ichiro; Sue, Kiwamu; Ookawara, Ryuto; Wakashima, Yuichiro; Suzuki, Akira

    2015-12-01

    In the synthesis of metal oxide fine particles by continuous supercritical hydrothermal method, the particle characteristics are greatly affected by not only the reaction conditions (temperature, pressure, residence time, concentration, etc.), but also the heating rate from ambient to reaction temperature. Therefore, the heating method by direct mixing of starting solution at room temperature with supercritical water is a key technology for the particle production having smaller size and narrow distribution. In this paper, mixing engineering study through comparison between conventional T-shaped mixers and recently developed swirl mixers was carried out in the hydrothermal synthesis of NiO nanoparticles from Ni(NO3)2 aqueous solution at 400 °C and 30 MPa. Inner diameter in the mixers and total flow rates were varied. Furthermore, the heating rate was calculated by computational fluid dynamics (CFD) simulation. Relationship between the heating rate and the average particle size were discussed. It was clarified that the miniaturization of mixer inner diameter and the use of the swirl flow were effective for improving mixing performance and contributed to produce small and narrow distribution particle under same experimental condition of flow rate, temperature, pressure, residence time, and concentration of the starting materials. We have focused the mixer optimization due to a difference in fluid viscosity.

  14. Influence of Superheated Steam Temperature Regulation Quality on Service Life of Boiler Steam Super-Heater Metal

    Directory of Open Access Journals (Sweden)

    G. T. Kulakov

    2009-01-01

    Full Text Available The paper investigates influence of change in quality of superheated steam temperature regulations on service life of super-heater metal. А dependence between metal service life and dispersion value for different steel grades has been determined in the paper. Numerical values pertaining to increase of super-heater metal service life in case of transferring from manual regulation to standard system of automatic regulation (SAR have been determined and in case of transferring from standard SAR to improved SAR. The analysis of tabular data and plotted dependencies makes it possible to conclude that any change in conditions of convection super-heater metal work due to better quality of the regulation leads to essential increase of time period which is left till the completion of the service life of a super-heater heating surface.

  15. Steam turbine of domestic (ultra) critical unit steam turbine temperature low risk analysis and Suggestions%超(超)临界机组汽轮机蒸汽温度低风险分析及建议

    Institute of Scientific and Technical Information of China (English)

    靖长财

    2012-01-01

    Supercritical (ultra) steam turbine of guohua company steam temperature low risk be analyzed, In The principles of the protection configuration, Protection setting characteristics, rotection setting mode, Protection setting value selection and Operating control measures. To protect the turbine safety operation has certain significance.%从保护配置的原则、保护设置特点、保护设置方式、保护定值选取、运行控制措施等方面,分析国华公司超(超)临界机组汽轮机蒸汽温度低存在的风险,对保护汽轮机安全运行具有一定的借鉴意义。

  16. Processing urinary endoscopes in a low-temperature steam and formaldehyde autoclave.

    Science.gov (United States)

    Gibson, G L

    1977-01-01

    Methods of disinfection and sterilisation of urinary endoscopes are considered. A small mobile low-temperature steam and formaldehyde autoclave (Miniclave 80) is evaluated and shown to be satisfactory for this purpose as judged by a variety of relevant microbiological test pieces. Images PMID:557503

  17. Ultra supercritical pressure. Cho rinkaiatsu kara chocho rinkaiatsu e

    Energy Technology Data Exchange (ETDEWEB)

    Matsuo, T. (Mitsubishi Heavy Industries Ltd., Tokyo (Japan))

    1992-10-05

    In Japanese thermoelectric power plants the steam condition was made higher in pressure and temperature with a rise in the requirement to enhance the plant efficiency being spurred by a rapid increasement in the demand of electric power since 1955. It was 1967 when a supercritical power plant of 24.2 MPa steam pressure started its operation. Afterwards, the enhancement of the plant efficiency by upgrading the steam condition was again paid attention against the sharp rise in fuel cost caused by oil shock in two times originating from 1973. In 1989 Japan's first ultra supercritical pressure plant of 31.1 MPa steam pressure, Kawagoe No.1 of Chubu Electric Power Co.,Inc. began its operation and achieved an efficiency of 41.9 %, approximately 5 % higher than hitherto. In Kawagoe No.1 boiler, a 9Cr-1 Mo system material excellent in high temperature strength was put to practical use and applied to main steam tubes and super-heater tube exit headers, also a fine grained 18Cr-11Ni-Nb-Ta steel excellent in high temperature strength as well as steam oxidizing property was developed and adopted to super-heater tubes. Thus, the reduction of thermal stress and the improvement of responsiveness were attained by thinning the thickness of tube with these materials. 3 refs., 2 figs.

  18. Analytical approximations for temperature dependent thermophysical properties of supercritical diesel fuel surrogates used in combustion modeling

    Science.gov (United States)

    Kumar, Abhinav; Saini, Vishnu; Dondapati, Raja Sekhar; Usurumarti, Preeti Rao

    2017-07-01

    Supercritical fluid technology is introduced to combat the critical challenges related with emissions, incomplete and clean diesel fuel combustion. The chemical kinetics of diesel fuel is a strong function of temperature. As surrogate fuels have a potential to represent a real diesel fuel, thermophysical properties of such fuels have been studied in this present work as a function of temperature. Further, two diesel surrogate fuels which have been identified as the components of actual diesel fuel for jet engines are studied and thermophysical properties of these two surrogates are evaluated as a function of temperature at critical pressure. In addition, the accuracy and reliability of the developed correlations is estimated using two statistical parameters such as Absolute Average of Relative Error (AARE) and Sum of Average Residues (SAR). Results show an excellent agreement between the standard data and the correlated property values.

  19. Optimum temperature policy for sorption enhanced steam methane reforming process for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Retnamma, Rajasree [National Laboratory of energy and Geology (LNEG), Lisbon (PT). Energy Systems Modeling and Optimization Unit (UMOSE); Ravi Kumar, V.; Kulkarni, B.D. [National Chemical Laboratory, Pune (India). Chemical Engineering and Process Development

    2010-07-01

    Sorption enhanced steam methane reforming (SE-SMR) process offers high potential for producing H{sub 2} in fuel cell applications compared to conventional catalytic steam methane reforming (SMR) process. The reactor temperature can significantly affect the performance of the SE-SMR reaction and simultaneous adsorption behavior of CO{sub 2}. Determination of an optimal temperature policy in SE-SMR reactor is therefore an important optimization issue. Multi-stage operation is a possible way to implement optimum temperature policies. In the present work, simulation study has been carried out for multi-stage operation using a mathematical model incorporating basic mechanisms operating in a fixed bed reactor with nonlinear reaction kinetic features of an SE-SMR process. Three cases were considered for implementing the multi-stage concept and the results show that increase in temperature based on a policy leads to considerable improvement in the process performance. (orig.)

  20. 1000 MW超超临界汽轮机高压外缸蠕变强度的分析%Creep Strength Analysis on HP Outer Casing of a 1 000 MW Ultra Supercritical Steam Turbine

    Institute of Scientific and Technical Information of China (English)

    蒋浦宁

    2013-01-01

    以1 000 MW超超临界汽轮机高压外缸为研究对象,通过引入Norton-Bailey材料蠕变本构方程和Cocks-Ashby多轴韧度系数,对汽缸轴对称二维模型的温度场、应力场和CA蠕变等效应变分布进行了计算,找出了结构设计中不合理区域并提出相应的结构改进方案.结果表明:经改进的高压外缸结构设计是合理的;CA蠕变等效应变计算结果均小于推荐考核标准,该1 000 MW超超临界汽轮机高压外缸的高温蠕变应变强度能够满足设计要求.%Taking the high-pressure outer casing of a 1 000 MW ultra supercritical steam turbine as an object of study, and by adopting the Norton-Bailey material creep constitutive equation and Cocks-Ashby multiaxial coefficient, the temperature field, stress field and the CA equivalent creep strain dictribution of the 2D axisymmetric model were calculated, during which the unreasonable structure of original design was found out and impoved with corresponding schemes. Results show that the improved structure of the HP outer casing is reasonable; all the calculated results of CA equivalent creep strain are less than those in the recommended criteria for assessment. The high-temperature creep strain of above mentioned outer casing can meet the design requirements.

  1. Steam Turbine Materials and Corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, G.H.; Hsu, D.H.

    2008-07-01

    Ultra-supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760 °C. In prior years this project examined the steamside oxidation of alloys for use in high- and intermediate-pressure USC turbines. This steamside oxidation research is continuing and progress is presented, with emphasis on chromia evaporation.

  2. Universal One-Parametric Dependence of Dielectric Water and Water Steam Permeability on Density-Temperature Ratio

    OpenAIRE

    Yu. V. Mulev; K. M. Arefiev; O. V. Beliayeva; M. Yu. Mulev; T. A/ Zaiats

    2011-01-01

    Available experimental data on dielectric permeability of water and water steam have been analyzed in the paper. The paper presents an universal one-parametric dependence of dielectric water and water steam permeability in single-phase areas and also on boundary curves on density -temperature ratio.

  3. Universal One-Parametric Dependence of Dielectric Water and Water Steam Permeability on Density-Temperature Ratio

    Directory of Open Access Journals (Sweden)

    Yu. V. Mulev

    2011-01-01

    Full Text Available Available experimental data on dielectric permeability of water and water steam have been analyzed in the paper. The paper presents an universal one-parametric dependence of dielectric water and water steam permeability in single-phase areas and also on boundary curves on density -temperature ratio.

  4. Interaction of titanium beryllide with steam at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Munakata, Kenzo, E-mail: kenzo.munakata@gmail.com [Faculty of Engineering and Resource Science, Akita University, 1-1, Tegatagakuen-cho, Akita 010-8502 (Japan); Wada, Kohei; Akimoto, Yusuke; Takeda, Haruki; Nakamura, Ayano [Faculty of Engineering and Resource Science, Akita University, 1-1, Tegatagakuen-cho, Akita 010-8502 (Japan); Kim, Jae-Hwan; Nakamichi, Masaru [Fusion Research and Development Directorate, Japan Atomic Energy Agency, 2-166, Omotedate, Obuchi, Rokkasho, Kamikita, Aomori 039-3212 (Japan)

    2014-10-15

    Highlights: • Some central and peripheral parts of a plasma sintered titanium beryllide disk were exposed to water vapor at 1273 K. • H{sub 2} gas generation rate of the central part was found to be lower than that of the peripheral part. • Central parts of a plasma sintered titanium beryllide disk were exposed to water vapor at 1273 K with different temperature controls. • H{sub 2} gas generation was found to be affected by thermal treatment. - Abstract: Some central and peripheral parts of a plasma sintered titanium beryllide disk were exposed to water vapor at temperatures raised up to 1273 K. Hydrogen generation and oxidation properties of the titanium beryllide were investigated. The amount of H{sub 2} generation of the central part was found to be smaller than that of the peripheral part, and this can be attributed to difference in the larger fractions of the Be phase on their surface. Thus, different temperature programed experiments were performed using samples cut out from the central part. In an experiment, the temperature of the sample was raised stepwise and behavior of hydrogen generation was investigated. It was found that hydrogen generation does not take place at the temperatures below 1273 K and the amount of hydrogen generated is far smaller. Another experiment was carried out after a sample had been annealed under a dry Ar gas at 1273 K. In this case, the amount of hydrogen generated from the surface decreased. These results indicate the thermal treatment of the titanium beryllide samples affects their reactivity with water vapor.

  5. Design and evaluation of a high temperature/pressure supercritical carbon dioxide direct tubular receiver for concentrating solar power applications

    Science.gov (United States)

    Ortega, Jesus Daniel

    This work focuses on the development of a solar power thermal receiver for a supercritical-carbon dioxide (sCO2), Brayton power-cycle to produce ~1 MWe. Closed-loop sCO2 Brayton cycles are being evaluated in combination with concentrating solar power to provide higher thermal-to-electric conversion efficiencies relative to conventional steam Rankine cycles. High temperatures (923--973 K) and pressures (20--25 MPa) are required in the solar receiver to achieve thermal efficiencies of ~50%, making concentrating solar power (CSP) technologies a competitive alternative to current power generation methods. In this study, the CSP receiver is required to achieve an outlet temperature of 923 K at 25 MPa or 973 K at 20 MPa to meet the operating needs. To obtain compatible receiver tube material, an extensive material review was performed based the ASME Boiler and Pressure Vessel Code, ASME B31.1 and ASME B313.3 codes respectively. Subsequently, a thermal-structural model was developed using a commercial computational fluid (CFD) dynamics and structural mechanics software for designing and analyzing the tubular receiver that could provide the heat input for a ~2 MWth plant. These results were used to perform an analytical cumulative damage creep-fatigue analysis to estimate the work-life of the tubes. In sequence, an optical-thermal-fluid model was developed to evaluate the resulting thermal efficiency of the tubular receiver from the NSTTF heliostat field. The ray-tracing tool SolTrace was used to obtain the heat-flux distribution on the surfaces of the receiver. The K-ω SST turbulence model and P-1 radiation model used in Fluent were coupled with SolTrace to provide the heat flux distribution on the receiver surface. The creep-fatigue analysis displays the damage accumulated due to the cycling and the permanent deformation of the tubes. Nonetheless, they are able to support the required lifetime. The receiver surface temperatures were found to be within the safe

  6. Low temperature synthesis of fibres composed of carbon-nickel nanoparticles in super-critical carbon dioxide

    Science.gov (United States)

    Hasumura, Takashi; Fukuda, Takahiro; Whitby, Raymond L. D.; Aschenbrenner, Ortrud; Maekawa, Toru

    2010-06-01

    We show that fibres composed of carbon-nickel nanoparticles are self-assembled by mixing nickelocene and oxygen with super-critical carbon dioxide in a dc electric field. The fibres grow in the direction of the electric field and the growth rate increases with an increase in the strength of the electric field. We also irradiate the fibres with electron beams and find that crystallized nickel particles are captured by carbon particles. The present result suggests that a low temperature method of creating carbon-metal hybrid nanostructures may be developed by mixing metallocene and trigger molecules with super-critical fluids subjected to a dc electric field.

  7. Application of Stable-pressure Steam Purging Technology in 660MW Supercritical Once--through Boiler%660MW超临界机组稳压吹管的实践

    Institute of Scientific and Technical Information of China (English)

    郭刚; 邢燕

    2011-01-01

    Combining with the engineering practice of stable-pressure steam purging in 660 MW supercritical once-through boiler,and calculating the steam purging parameters, the application was analyzed in some aspects including parameter selection ,parameter contro%通过对超临界机组的吹管参数的计算,结合稳压吹管的实践,从吹管参数的选择、吹管过程中参数的控制以及系统的变更等几个方面进行了分析总结,对超临界机组的吹管具有一定的借鉴意义。

  8. Corrosion behavior of construction materials for intermediate temperature steam electrolysers

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Petrushina, Irina; Jensen, Jens Oluf

    2013-01-01

    Different corrosion resistant stainless steels, nickel-based alloys, pure nickel, Ta-coated stainless steel (AISI 316L), niobium, platinum and gold rods were evaluated as possible materials for use in the intermediate temperature (200-400 °C) acidic water electrolysers. The corrosion resistance...... was measured under simulated conditions (molten KH2PO4) corresponding to the proton-conducting solid acids or transition metal phosphates as electrolytes. It was shown that, unlike at temperatures below 200 °C, gold is unstable with respect to corrosion in molten KH2PO4. Platinum demonstrated high corrosion...... resistance and the anodic and cathodic limits were for the first time found for the electrolyte. Nickel, niobium, Inconel®625, Hastelloy®C-276 and Ta-coated stainless steel (AISI 316L) demonstrated high corrosion stability and can be recommended as construction materials for bipolar plates. © (2013) Trans...

  9. The performance of a temperature cascaded cogeneration system producing steam, cooling and dehumidification

    KAUST Repository

    Myat, Aung

    2013-02-01

    This paper discusses the performance of a temperature-cascaded cogeneration plant (TCCP), equipped with an efficient waste heat recovery system. The TCCP, also called a cogeneration system, produces four types of useful energy-namely, (i) electricity, (ii) steam, (iii) cooling and (iv) dehumidification-by utilizing single fuel source. The TCCP comprises a Capstone C-30 micro-turbine that generates nominal capacity of 26 kW of electricity, a compact and efficient waste heat recovery system and a host of waste-heat-activated devices, namely (i) a steam generator, (ii) an absorption chiller, (iii) an adsorption chiller and (iv) a multi-bed desiccant dehumidifier. The performance analysis was conducted under different operation conditions such as different exhaust gas temperatures. It was observed that energy utilization factor could be as high as 70% while fuel energy saving ratio was found to be 28%. © 2013 Desalination Publications.

  10. Steam reforming of tars at low temperature and elevated pressure for model tar component naphthalene

    OpenAIRE

    Speidel, Michael; Fischer, Holger

    2016-01-01

    A process of pressurized gasification and power generation in a hybrid system of Solid Oxide Fuel Cell (SOFC) and gas turbine enables an efficient use of biomass. This process requires tar reforming in order to protect the SOFC from plugging. Tars must be converted at 5 bar absolute pressure (bara) while avoiding secondary steam reforming of methane in order to reduce the required heat input for the tar reformer. This can be realized at low reforming temperatures (

  11. Multifactorial modelling of high-temperature treatment of timber in the saturated water steam medium

    Science.gov (United States)

    Prosvirnikov, D. B.; Safin, R. G.; Ziatdinova, D. F.; Timerbaev, N. F.; Lashkov, V. A.

    2016-04-01

    The paper analyses experimental data obtained in studies of high-temperature treatment of softwood and hardwood in an environment of saturated water steam. Data were processed in the Curve Expert software for the purpose of statistical modelling of processes and phenomena occurring during this process. The multifactorial modelling resulted in the empirical dependences, allowing determining the main parameters of this type of hydrothermal treatment with high accuracy.

  12. High temperature electrolysis of steam and carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Hoejgaard Jensen, Soeren [H.C. Oersted Institute, Copenhagen (Denmark); Hoegh, Jens V.T.; Barfod, Rasmus; Mogensen, Mogens [Risoe National Lab., Materials Research Dept., Roskilde (Denmark)

    2003-09-01

    The vision behind this work is establishment of methods for cheap production of hydrogen, H{sub 2}, and methane, CH{sub 4}, by electrolysis. CH{sub 4} is a particular suitable storage medium for renewable energy. Preliminary electrolysis experiments with a second generation of solid oxide fuel cells developed at Risoe National Laboratory, Denmark, show that these cells also have a high potential as solid oxide electrolyse cells. Furthermore, the experiments indicate that production of CH{sub 4} by high temperature electrolysis of mixtures of H{sub 2} and CO{sub 2} is possible using these cells, but very high gas pressure seems necessary to obtain acceptable yields. The results also indicate that much more research and development work is needed in order to make a sufficient durable electrolyse cell. (au)

  13. Modified Korteweg-de Vries solitons at supercritical densities in two-electron temperature plasmas

    CERN Document Server

    Verheest, Frank; Hereman, Willy A

    2016-01-01

    The supercritical composition of a plasma model with cold positive ions in the presence of a two-temperature electron population is investigated, initially by a reductive perturbation approach, under the combined requirements that there be neither quadratic nor cubic nonlinearities in the evolution equation. This leads to a unique choice for the set of compositional parameters and a modified Korteweg-de Vries equation (mKdV) with a quartic nonlinear term. The conclusions about its one-soliton solution and integrability will also be valid for more complicated plasma compositions. Only three polynomial conservation laws can be obtained. The mKdV equation with quartic nonlinearity is not completely integrable, thus precluding the existence of multi-soliton solutions. Next, the full Sagdeev pseudopotential method has been applied and this allows for a detailed comparison with the reductive perturbation results. This comparison shows that the mKdV solitons have slightly larger amplitudes and widths than those obta...

  14. Systems Engineering Provides Successful High Temperature Steam Electrolysis Project

    Energy Technology Data Exchange (ETDEWEB)

    Charles V. Park; Emmanuel Ohene Opare, Jr.

    2011-06-01

    This paper describes two Systems Engineering Studies completed at the Idaho National Laboratory (INL) to support development of the High Temperature Stream Electrolysis (HTSE) process. HTSE produces hydrogen from water using nuclear power and was selected by the Department of Energy (DOE) for integration with the Next Generation Nuclear Plant (NGNP). The first study was a reliability, availability and maintainability (RAM) analysis to identify critical areas for technology development based on available information regarding expected component performance. An HTSE process baseline flowsheet at commercial scale was used as a basis. The NGNP project also established a process and capability to perform future RAM analyses. The analysis identified which components had the greatest impact on HTSE process availability and indicated that the HTSE process could achieve over 90% availability. The second study developed a series of life-cycle cost estimates for the various scale-ups required to demonstrate the HTSE process. Both studies were useful in identifying near- and long-term efforts necessary for successful HTSE process deployment. The size of demonstrations to support scale-up was refined, which is essential to estimate near- and long-term cost and schedule. The life-cycle funding profile, with high-level allocations, was identified as the program transitions from experiment scale R&D to engineering scale demonstration.

  15. Multitechnique characterisation of 304L surface states oxidised at high temperature in steam and air atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Mamede, Anne-Sophie, E-mail: anne-sophie.mamede@ensc-lille.fr [University Lille, CNRS, ENSCL, Centrale Lille, University Artois, UMR 8181 – UCCS – Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Nuns, Nicolas, E-mail: nicolas.nuns@univ-lille1.fr [University Lille, CNRS, ENSCL, Centrale Lille, University Artois, UMR 8181 – UCCS – Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Cristol, Anne-Lise, E-mail: anne-lise.cristol@ec-lille.fr [University Lille, CNRS, Centrale Lille, Arts et Métiers Paris Tech, FRE 3723 – LML – Laboratoire de Mécanique de Lille, F-59000 Lille (France); Cantrel, Laurent, E-mail: laurent.cantrel@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire, PSN-RES, Cadarache, Saint Paul lez Durance, 13115 (France); Laboratoire de Recherche Commun IRSN-CNRS-Lille 1: «Cinétique Chimique, Combustion, Réactivité» (C3R), Cadarache, Saint Paul lez Durance, 13115 (France); Souvi, Sidi, E-mail: sidi.souvi@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire, PSN-RES, Cadarache, Saint Paul lez Durance, 13115 (France); Laboratoire de Recherche Commun IRSN-CNRS-Lille 1: «Cinétique Chimique, Combustion, Réactivité» (C3R), Cadarache, Saint Paul lez Durance, 13115 (France); and others

    2016-04-30

    Graphical abstract: - Highlights: • Mutitechnique characterisation of oxidised 304L. • Oxidation at high temperature under steam and air conditions of 304L stainless steel. • Chromium and manganese oxides formed in the outer layer. • Oxide profiles differ in air or steam atmosphere. - Abstract: In case of a severe accident occurring in a nuclear reactor, surfaces of the reactor coolant system (RCS), made of stainless steel (304L) rich in Cr (>10%) and Ni (8–12%), are oxidised. Fission products (FPs) are released from melt fuel and flow through the RCS. A part of them is deposited onto surfaces either by vapour condensation or by aerosol deposition mechanisms. To be able to understand the nature of interactions between these FPs and the RCS surfaces, a preliminary step is to characterize the RSC surface states in steam and air atmosphere at high temperatures. Pieces of 304L stainless steel have been treated in a flow reactor at two different temperatures (750 °C and 950 °C) for two different exposition times (24 h and 72 h). After surfaces analysing by a unique combination of surface analysis techniques (XPS, ToF-SIMS and LEIS), for 304L, the results show a deep oxide scale with multi layers and the outer layer is composed of chromium and manganese oxides. Oxide profiles differ in air or steam atmosphere. Fe{sub 2}O{sub 3} oxide is observed but in minor proportion and in all cases no nickel is detected near the surface. Results obtained are discussed and compared with the literature data.

  16. Research and Development of Heat-Resistant Materials for Advanced USC Power Plants with Steam Temperatures of 700 °C and Above

    Directory of Open Access Journals (Sweden)

    Fujio Abe

    2015-06-01

    Full Text Available Materials-development projects for advanced ultra-supercritical (A-USC power plants with steam temperatures of 700 °C and above have been performed in order to achieve high efficiency and low CO2 emissions in Europe, the US, Japan, and recently in China and India as well. These projects involve the replacement of martensitic 9%−12% Cr steels with nickel (Ni-base alloys for the highest temperature boiler and turbine components in order to provide sufficient creep strength at 700°C and above. To minimize the requirement for expensive Ni-base alloys, martensitic 9%−12% Cr steels can be applied to the next highest temperature components of an A-USC power plant, up to a maximum of 650°C. This paper comprehensively describes the research and development of Ni-base alloys and martensitic 9%−12% Cr steels for thick section boiler and turbine components of A-USC power plants, mainly focusing on the long-term creep-rupture strength of base metal and welded joints, strength loss in welded joints, creep-fatigue properties, and microstructure evolution during exposure at elevated temperatures.

  17. Hydrogen-rich gas production by steam gasification of char from biomass fast pyrolysis in a fixed-bed reactor: influence of temperature and steam on hydrogen yield and syngas composition.

    Science.gov (United States)

    Yan, Feng; Luo, Si-yi; Hu, Zhi-quan; Xiao, Bo; Cheng, Gong

    2010-07-01

    Steam gasification experiments of biomass char were carried out in a fixed-bed reactor. The experiments were completed at bed temperature of 600-850 degrees C, a steam flow rate of 0-0.357 g/min/g of biomass char, and a reaction time of 15min. The aim of this study is to determine the effects of bed temperature and steam flow rate on syngas yield and its compositions. The results showed that both high gasification temperature and introduction of proper steam led to higher yield of dry gas and higher carbon conversion efficiency. However, excessive steam reduced gas yield and carbon conversion efficiency. The maximum dry gas yield was obtained at the gasification temperature of 850 degrees C and steam flow rate of 0.165 g/min/g biomass char.

  18. Application of Flexible Micro Temperature Sensor in Oxidative Steam Reforming by a Methanol Micro Reformer

    Directory of Open Access Journals (Sweden)

    Yi-Man Lo

    2011-02-01

    Full Text Available Advances in fuel cell applications reflect the ability of reformers to produce hydrogen. This work presents a flexible micro temperature sensor that is fabricated based on micro-electro-mechanical systems (MEMS technology and integrated into a flat micro methanol reformer to observe the conditions inside that reformer. The micro temperature sensor has higher accuracy and sensitivity than a conventionally adopted thermocouple. Despite various micro temperature sensor applications, integrated micro reformers are still relatively new. This work proposes a novel method for integrating micro methanol reformers and micro temperature sensors, subsequently increasing the methanol conversion rate and the hydrogen production rate by varying the fuel supply rate and the water/methanol ratio. Importantly, the proposed micro temperature sensor adequately controls the interior temperature during oxidative steam reforming of methanol (OSRM, with the relevant parameters optimized as well.

  19. Effects of Supercritical Fluids, Pressure, Temperature, and Molecular Structure on the Rheological Properties of Molten Polymers

    Science.gov (United States)

    Park, Hee Eon; Dealy, John M.

    2008-07-01

    Since high pressures are involved in most plastics forming processes, reliable high-pressure rheological data are required for the simulation of the processes. The effect of pressure is in some ways the reverse of that of temperature; for example increasing temperature decreases the viscosity, while pressure increases it. Supercritical fluids (SCFs) such as carbon dioxide and nitrogen can act as physical blowing agents in the manufacture of foams and as plasticizers to reduce melt viscosity during processing. The effects of dissolved SCF, pressure, and temperature on the rheological properties of a melt must be known to achieve optimum processing conditions. We used a rotational rheometer and a high-pressure sliding plate rheometer, in which the shear strain, temperature, pressure, and SCF concentration are all uniform. A shear stress transducer senses the stress in the center of the sample to avoid edge effects. It was possible to use shift factors for temperature, pressure and SCF (CO2 or N2) concentration to obtain a master curve. The effect of temperature could be described by the Arrhenius or WLF models, and the effect of pressure was described by the Barus equation. The effect of SCF concentration could be described by the Fujita-Kishimoto equation. The relative effects of pressure and temperature on the viscosity were quantified. To study the effects of short and long chain branching and a phenyl side group, three polymers were used: polyethylene, polypropylene, and polystyrene. We quantified the effects of short- and long-chain branching, pressure, temperature and dissolved SCF on the rheological properties of these three polymers by use of shift factors.

  20. Thermodynamic optimisation of supercritical CO2 Brayton power cycles coupled to Direct Steam Generation Line-Focusing solar fields

    OpenAIRE

    Coco Enriquez, Luis; Muñoz Antón, Javier; Martínez-Val Peñalosa, Jose Maria

    2016-01-01

    In this paper a new generation line-focusing solar plants coupled to a s-CO2 Brayton power cycles are studied. These innovative CSP will increase the plant energy efficiency, and subsequently optimizing the SF effective aperture area and SF investment cost for a fixed power output. Two SF configurations were assessed: the Configuration 1 with a condenser between the SF and the Balance Of Plant (BOP), for Turbine Inlet Temperatures (TIT) up to 400oC, and the Configuration 2, for higher TIT up ...

  1. Long term steam oxidation of TP 347H FG in power plants

    DEFF Research Database (Denmark)

    Hansson, Anette Nørgaard; Korcakova, Leona; Hald, John

    2005-01-01

    The long term oxidation behaviour of TP 347H FG at ultra supercritical steam conditions was assessed by exposing the steel in test superheater loops in a Danish coal-fired power plant. The steamside oxide layer was investigated with scanning electron microscopy and energy dispersive Xray diffract......The long term oxidation behaviour of TP 347H FG at ultra supercritical steam conditions was assessed by exposing the steel in test superheater loops in a Danish coal-fired power plant. The steamside oxide layer was investigated with scanning electron microscopy and energy dispersive Xray...... diffraction in order to reveal the effect of oxidation time and temperature on the microstructure. A double layered oxide formed during steam oxidation. The morphology of the inner Cr-containing layer was influenced by the oxidation temperature. At temperatures below 585 degrees C, it consisted of regions...

  2. Simulation of Low-Temperature Coal Tar Hydrocracking in Supercritical Gasoline

    Institute of Scientific and Technical Information of China (English)

    Zhang Lei; Liu Zongkuan; Gu Zhaolin

    2013-01-01

    The aim of this paper was preliminary design of the process for low-temperature coal tar hydrocracking in supercritical gasoline based on Aspen Plus with the concept of energy self-sustainability. In order to ensure the correct-ness and accuracy of the simulation, we did the following tasks: selecting reasonable model compounds for low-tem-perature coal tar; describing the nature of products gasoline and diesel accurately; and conifrming the proper property study method for each block by means of experience and trial. The purpose of energy self-sustainability could be pos-sibly achieved, on one hand, by using hot stream to preheat cold stream and achieving temperature control of streams, and on the other hand, by utilizing gas (byproduct of the coal tar hydrocracking) combustion reaction to provide energy. Results showed that the whole process could provide a positive net power of about 609 kW·h for processing the low-temperature coal tar with a lfowrate of 2 268 kg/h. The total heat recovery amounted to 2 229 kW·h, among which 845 kW·h was obtained from the gas combustion reaction, and 1 116 kW·h was provided by the reactor’s outlet stream, with the rest furnished by hot streams of the products gasoline, diesel and residue. In addition, the process lfow sheet could achieve products separation well, and speciifcally the purity of product gasoline and diesel reached 97.2% and 100%, respectively.

  3. Formation of Magnesite at Low Temperature in Mineral:Supercritical CO2 Systems

    Science.gov (United States)

    Qafoku, O.; Hu, J.; Arey, B.; Liu, J.; Ilton, E. S.; Felmy, A.

    2013-12-01

    One of the most promising options for mitigating the impacts of greenhouse gases on global warming is storage and sequestration of the anthropogenic CO2 in deep geologic formations. Consequently, evaluating mineral-fluid interaction in aqueous systems saturated with supercritical CO2 (scCO2) has been the focus for subsurface CO2 storage research. An important factor in assessing mineral-fluid interactions is the potential for the formation of stable divalent metal carbonates, principally Ca and Mg, which can immobilize the disposed CO2 as mineral precipitates. The formation of some of these phases, especially the Mg anhydrous phase magnesite (MgCO3), has been hindered by slow precipitation kinetics owing to the strong affinity of Mg2+ ion for the waters of hydration. Understanding conditions that lead to formation of magnesite at temperatures significant to subsurface disposal of CO2 can be substantial in the development of efficient carbon sequestration techniques. Here we present recently obtained experimental data on the formation of magnesite at low temperature (as low as 350C) and microscopy data that can elucidate factors that might contribute to magnesite formation. The experimental studies were conducted over a range of temperature, pressure, pH, and initial Mg(HCO3)2 concentration to map out the specific solution phase conditions which result in nucleation of magnesite in aqueous solution saturated with scCO2.

  4. Analyses of Temperature Field and Deflection of Steam Turbine IP Inlet Flow Guide%汽轮机中压进汽导流环温度场及变形分析

    Institute of Scientific and Technical Information of China (English)

    王林

    2014-01-01

    IP inlet flow guide is one of the key components in steam turbine,analyses of temperature field and deflection are important when flow guide of steam turbine is designed.Aim at a 600MW sub-critical steam turbine flow guide,a finite element model is developed,methods for calculating the heat transfer coefficients of flow guide surfaces different regions are described,the finite element thermal and structural analyses are performed on the flow guide.Detailed temperature and deflection distributions are determined during the steady operating conditions.The results show that radial temperature gradient is principal,radial deflection of flow guide foot is 1.611 3mm,radial deflection of flow guide with seal is 2.063 6 mm.The used analytic methods can be applied for temperature field and deflection analyses of sub-critical,supercritical and ultra-supercritical steam turbine flow guide,a basis for the bolting analysis and the cooling structural design of steam turbine flow guide is provided.%中压进汽导流环是汽轮机中的关键部件,在设计过程中必须分析其温度场及变形。针对某亚临界600MW汽轮机导流环,建立了有限元模型,介绍了导流环表面不同区域的传热系数计算方法,用有限元法分析了导流环的温度场和变形,得出了在稳态运行工况的详细温度和变形分布。结果表明,导流环温度梯度以径向为主,导流环的最下部径向变形为1.6113mm,导流环安装汽封处径向变形为2.0636mm。所采用的分析方法可以用于分析亚临界、超临界和超超临界汽轮机导流环的温度场和变形,为导流环螺栓分析和冷却结构设计打下基础。

  5. Steam gasification of waste tyre: Influence of process temperature on yield and product composition

    Energy Technology Data Exchange (ETDEWEB)

    Portofino, Sabrina, E-mail: sabrina.portofino@enea.it [UTTP NANO – C.R. ENEA Portici, P.le E. Fermi, 1 Loc. Granatello, 80055 Portici (Italy); Donatelli, Antonio; Iovane, Pierpaolo; Innella, Carolina; Civita, Rocco; Martino, Maria; Matera, Domenico Antonio; Russo, Antonio; Cornacchia, Giacinto [UTTTRI RIF – C.R. ENEA Trisaia, SS Jonica 106, km 419.5, 75026 Rotondella (Italy); Galvagno, Sergio [UTTP NANO – C.R. ENEA Portici, P.le E. Fermi, 1 Loc. Granatello, 80055 Portici (Italy)

    2013-03-15

    Highlights: ► Steam gasification of waste tyre as matter and energy recovery treatment. ► Process temperature affects products yield and gas composition. ► High temperature promotes hydrogen production. ► Char exploitation as activated carbon or carbon source. - Abstract: An experimental survey of waste tyre gasification with steam as oxidizing agent has been conducted in a continuous bench scale reactor, with the aim of studying the influence of the process temperature on the yield and the composition of the products; the tests have been performed at three different temperatures, in the range of 850–1000 °C, holding all the other operational parameters (pressure, carrier gas flow, solid residence time). The experimental results show that the process seems promising in view of obtaining a good quality syngas, indicating that a higher temperature results in a higher syngas production (86 wt%) and a lower char yield, due to an enhancement of the solid–gas phase reactions with the temperature. Higher temperatures clearly result in higher hydrogen concentrations: the hydrogen content rapidly increases, attaining values higher than 65% v/v, while methane and ethylene gradually decrease over the range of the temperatures; carbon monoxide and dioxide instead, after an initial increase, show a nearly constant concentration at 1000 °C. Furthermore, in regards to the elemental composition of the synthesis gas, as the temperature increases, the carbon content continuously decreases, while the oxygen content increases; the hydrogen, being the main component of the gas fraction and having a small atomic weight, is responsible for the progressive reduction of the gas density at higher temperature.

  6. Study on Relative COP Changes with Increasing Heat Input Temperatures of Double Effect Steam Absorption Chillers

    Directory of Open Access Journals (Sweden)

    Abd Majid Mohd Amin

    2016-01-01

    Full Text Available Absorption chillers at cogeneration plants generate chilled water using steam supplied by heat recovery steam generators. The chillers are mainly of double effect type. The COP of double effect varies from 0.7 to 1.2 depending on operation and maintenance practices of the chillers. Heat input to the chillers during operations could have impact on the COP of the chillers. This study is on relative COP changes with increasing the heat input temperatures for a steam absorption chiller at a gas fueled cogeneration plant. Reversible COP analysis and zero order model were used for evaluating COP of the chiller for 118 days operation period. Results indicate increasing COP trends for both the reversible COP and zero model COP. Although the zero model COP are within the range of double effect absorption chiller, it is not so for the actual COP. The actual COP is below the range of normal double effect COP. It is recommended that economic replacement analysis to be undertaken to assess the feasibility either to repair or replace the existing absorption chiller.

  7. Lifetime evaluation of superheater tubes exposed to steam oxidation, high temperature corrosion and creep

    Energy Technology Data Exchange (ETDEWEB)

    Henriksen, N. [Elsamprojekt A/S, Faelleskemikerne, Fredericia (Denmark); Hede Larsen, O.; Blum, R. [I/S Fynsvaerket, Faelleskemikerne, Odense (Denmark)

    1996-12-01

    Advanced fossil fired plants operating at high steam temperatures require careful design of the superheaters. The German TRD design code normally used in Denmark is not precise enough for the design of superheaters with long lifetimes. The authors have developed a computer program to be used in the evaluation of superheater tube lifetime based on input related to tube dimensions, material, pressure, steam temperature, mass flux, heat flux and estimated corrosion rates. The program is described in the paper. As far as practically feasible, the model seems to give a true picture of the reality. For superheaters exposed to high heat fluxes or low internal heat transfer coefficients as is the case for superheaters located in fluidized bed environments or radiant environments, the program has been extremely useful for evaluation of surface temperature, oxide formation and lifetime. The total uncertainty of the method is mainly influenced by the uncertainty of the determination of the corrosion rate. More precise models describing the corrosion rate as a function of tube surface temperature, fuel parameters and boiler parameters need to be developed. (au) 21 refs.

  8. High-temperature steam oxidation kinetics of the E110G cladding alloy

    Science.gov (United States)

    Király, Márton; Kulacsy, Katalin; Hózer, Zoltán; Perez-Feró, Erzsébet; Novotny, Tamás

    2016-07-01

    In the course of recent years, several experiments were performed at MTA EK (Centre for Energy Research, Hungarian Academy of Sciences) on the isothermal high-temperature oxidation of the improved Russian cladding alloy E110G in steam/argon atmosphere. Using these data and designing additional supporting experiments, the oxidation kinetics of the E110G alloy was investigated in a wide temperature range, between 600 °C and 1200 °C. For short durations (below 500 s) or high temperatures (above 1065 °C) the oxidation kinetics was found to follow a square-root-of-time dependence, while for longer durations and in the intermediate temperature range (800-1000 °C) it was found to approach a cube-root-of-time dependence rather than a square-root one. Based on the results a new best-estimate and a conservative oxidation kinetics model were created.

  9. On the gasification of wet biomass in supercritical water : over de vergassing van natte biomassa in superkritiek water

    NARCIS (Netherlands)

    Withag, J.A.M.

    2013-01-01

    Supercritical water gasification (SCWG) is a challenging thermo-chemical conversion route for wet biomass and waste streams into hydrogen and/or methane. At temperatures and pressures above the critical point the physical properties of water differ strongly from liquid water or steam. Because of the

  10. Supercritical impregnation of polymer matrices spatially confined in microcontainers for oral drug delivery: Effect of temperature, pressure and time

    DEFF Research Database (Denmark)

    Marizza, Paolo; Pontoni, L.; Rindzevicius, Tomas

    2016-01-01

    parameters(temperature, pressure, time, drug concentration in the supercritical phase) was elucidated with respectto the loading capacity. The microcontainer filling was observed by means of optical macroimaging, X-ray microtomography and scanning electron microscopy. The physical state of the drug...... described. The drug loading can be controlled with high accuracy and reproducibility andthe impregnated drug is in amorphous state. These results demonstrate that SCI can be used as a highthroughput loading technique for microfabricated devices for oral drug delivery....

  11. Advance in highly efficient hydrogen production by high temperature steam electrolysis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    High Temperature Steam Electrolysis (HTSE) through a solid oxide electrolytic cell (SOEC) has been receiving increasing research and development attention worldwide because of its high conversion efficiency (about 45%-59%) and its potential usage for large-scale production of hydrogen. The mechanism, composition, structure, and developing challenges of SOEC are summarized. Current situation, key materials, and core technologies of SOEC (solid oxide electrolytic cell) in HTSE are re- viewed, and the prospect of HTSE future application in advanced energy fields is proposed. In addition, the recent research achievements and study progress of HTSE in Tsinghua University are also intro- duced and presented.

  12. Advance in highly efficient hydrogen production by high temperature steam electrolysis

    Institute of Scientific and Technical Information of China (English)

    YU Bo; ZHANG WenQiang; CHEN Jing; XU JingMing; WANG ShaoRong

    2008-01-01

    High Temperature Steam Electrolysis (HTSE) through a solid oxide electrolytic cell (SOEC) has been receiving increasing research and development attention worldwide because of its high conversion efficiency (about 45%-59%) and its potential usage for large-scale production of hydrogen. The mechanism, composition, structure, and developing challenges of SOEC are summarized. Current situation, key materials, and core technologies of SOEC (solid oxide electrolytic cell) in HTSE are re-viewed, and the prospect of HTSE future application in advanced energy fields is proposed. In addition, the recent research achievements and study progress of HTSE in Tsinghua University are also intro-duced and presented.

  13. Supercritical fluid extraction: Application in the food industry

    Directory of Open Access Journals (Sweden)

    Skala Dejan U.

    2002-01-01

    Full Text Available Supercritical fluid extraction is an extraction process realized with supercritical fluids, which are at a temperature and pressure above their critical temperature and critical pressure. This process has shown to be very efficient one for the isolation of different substances of medium molecular weights and molecules of relatively low polarity. The solubility of more polar substances in supercritical fluids can be improved by the addition of small amounts of other polar solvents (cosolvent to the supercritical fluids, which is the main solvent in extraction process. The advantage of supercritical extraction compared to other extraction procedures (the application of classical organic solvents hydrodistillation, distillation with steam is that SFE is usually performed at moderate temperature (e.g. with SF CO2 at 40-70°C so it can be applied for the separation of different substances which are thermally unstable and have a larger vapour pressure. All of these facts indicate that SFE is of special interest for the food and pharmaceutical industry.

  14. Solar energy conversion by using solar-pumped laser and high-temperature steam electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Arashi, Haruo; Nigara, Yutaka; Ishigame, Mareo

    1988-08-10

    For the purpose of conversion and storage of solar energy, the development of solar-pumped laser has been carried out from a stand point of the optical behavior, and the fundamental experimental study on high-temperature steam electrolysis has been performed from a view point of the thermal behavior. From these investigations, their effects on the utilization of solar energy were clarified. The solar radiation was successfully converted to a coherent laser radiation with wave length of 1.06 micro m by a water-cooled Nd:YAG laser rod in the solar concentrator with focal distance of 3.2m and diameter of 10m. The output of the laser of 40 W was obtained. The experiment on high-temperature steam electrolysis was conducted at the temperature range of 1070 to 1670 K in an electric furnace which simulates solar heating using ZrO/sub 2/ + 8 mol%Y/sub 2/O/sub 3/ as an electrolyte, and it was confirmed that hydrogen is produced with 92% in efficiency. (13 figs, 12 refs)

  15. Low temperature extraction and upgrading of oil sands and bitumen in supercritical fluid mixtures.

    Science.gov (United States)

    Brough, Sarah A; Riley, Sandra H; McGrady, G Sean; Tanhawiriyakul, Supaporn; Romero-Zerón, Laura; Willson, Christopher D

    2010-07-21

    Preliminary results are reported for the extraction and catalytic hydrocracking of Alberta bitumen and oil sands using supercritical fluid mixtures; high levels of extraction and upgrading were attained using reaction conditions significantly milder than those previously reported.

  16. High Temperature Monitoring the Height of Condensed Water in Steam Pipes

    Science.gov (United States)

    Bar-Cohen, Yoseph; Lih, Shyh-Shiuh; Badescu, Mircea; Bao, Xiaoqi; Sherrit, Stewart; Widholm, Scott; Ostlund, Patrick; Blosiu, Julian

    2011-01-01

    An in-service health monitoring system is needed for steam pipes to track through their wall the condensation of water. The system is required to measure the height of the condensed water inside the pipe while operating at temperatures that are as high as 250 deg. C. The system needs to be able to make real time measurements while accounting for the effects of cavitation and wavy water surface. For this purpose, ultrasonic wave in pulse-echo configuration was used and reflected signals were acquired and auto-correlated to remove noise from the data and determine the water height. Transmitting and receiving the waves is done by piezoelectric transducers having Curie temperature that is significantly higher than 250 deg. C. Measurements were made at temperatures as high as 250 deg. C and have shown the feasibility of the test method. This manuscript reports the results of this feasibility study.

  17. High Temperatures Health Monitoring of the Condensed Water Height in Steam Pipe Systems

    Science.gov (United States)

    Lih, Shyh-Shiuh; Bar-Cohen, Yoseph; Lee, Hyeong Jae; Badescu, Mircea; Bao, Xiaoqi; Sherrit, Stewart; Takano, Nobuyuki; Ostlund, Patrick; Blosiu, Julian

    2013-01-01

    Ultrasonic probes were designed, fabricated and tested for high temperature health monitoring system. The goal of this work was to develop the health monitoring system that can determine the height level of the condensed water through the pipe wall at high temperature up to 250 deg while accounting for the effects of surface perturbation. Among different ultrasonic probe designs, 2.25 MHz probes with air backed configuration provide satisfactory results in terms of sensitivity, receiving reflections from the target through the pipe wall. A series of tests were performed using the air-backed probes under irregular conditions, such as surface perturbation and surface disturbance at elevated temperature, to qualify the developed ultrasonic system. The results demonstrate that the fabricated air-backed probes combined with advanced signal processing techniques offer the capability of health monitoring of steam pipe under various operating conditions.

  18. High Temperature Monitoring the Height of Condensed Water in Steam Pipes

    Science.gov (United States)

    Bar-Cohen, Yoseph; Lih, Shyh-Shiuh; Badescu, Mircea; Bao, Xiaoqi; Sherrit, Stewart; Widholm, Scott; Ostlund, Patrick; Blosiu, Julian

    2011-01-01

    An in-service health monitoring system is needed for steam pipes to track through their wall the condensation of water. The system is required to measure the height of the condensed water inside the pipe while operating at temperatures that are as high as 250 deg. C. The system needs to be able to make real time measurements while accounting for the effects of cavitation and wavy water surface. For this purpose, ultrasonic wave in pulse-echo configuration was used and reflected signals were acquired and auto-correlated to remove noise from the data and determine the water height. Transmitting and receiving the waves is done by piezoelectric transducers having Curie temperature that is significantly higher than 250 deg. C. Measurements were made at temperatures as high as 250 deg. C and have shown the feasibility of the test method. This manuscript reports the results of this feasibility study.

  19. High Temperatures Health Monitoring of the Condensed Water Height in Steam Pipe Systems

    Science.gov (United States)

    Lih, Shyh-Shiuh; Bar-Cohen, Yoseph; Lee, Hyeong Jae; Badescu, Mircea; Bao, Xiaoqi; Sherrit, Stewart; Takano, Nobuyuki; Ostlund, Patrick; Blosiu, Julian

    2013-01-01

    Ultrasonic probes were designed, fabricated and tested for high temperature health monitoring system. The goal of this work was to develop the health monitoring system that can determine the height level of the condensed water through the pipe wall at high temperature up to 250 deg while accounting for the effects of surface perturbation. Among different ultrasonic probe designs, 2.25 MHz probes with air backed configuration provide satisfactory results in terms of sensitivity, receiving reflections from the target through the pipe wall. A series of tests were performed using the air-backed probes under irregular conditions, such as surface perturbation and surface disturbance at elevated temperature, to qualify the developed ultrasonic system. The results demonstrate that the fabricated air-backed probes combined with advanced signal processing techniques offer the capability of health monitoring of steam pipe under various operating conditions.

  20. Coupling of high temperature nuclear reactor with chemical plant by means of steam loop with heat pump

    Directory of Open Access Journals (Sweden)

    Kopeć Mariusz

    2017-01-01

    Full Text Available High temperature nuclear reactors (HTR can be used as an excellent, emission-free source of technological heat for various industrial applications. Their outlet helium temperature (700°-900°C allows not only for heat supply to all processes below 600°C (referred to as “steam class”, but also enables development of clean nuclear-assisted hydrogen production or coal liquefaction technologies with required temperatures up to 900°C (referred to as “chemical class”. This paper presents the results of analyses done for various configurations of the steam transport loop coupled with the high-temperature heat pump designed for “chemical class” applications. The advantages and disadvantages as well as the key issues are discussed in comparison with alternative solutions, trying to answer the question whether the system with the steam loop and the hightemperature heat pump is viable and economically justified.

  1. High Temperature Steam Oxidation Testing of Candidate Accident Tolerant Fuel Cladding Materials

    Energy Technology Data Exchange (ETDEWEB)

    Pint, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nelson, Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parker, Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parkison, Adam [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2013-12-23

    The Fuel Cycle Research and Development (FCRD) program’s Advanced Fuels Campaign has initiated a multifold effort aimed at facilitating development of accident tolerant fuels in order to overcome the inherent shortcomings of light water reactor (LWR) fuels when exposed to beyond design basis accident conditions. The campaign has invested in development of experimental infrastructure within the Department of Energy complex capable of chronicling the performance of a wide range of concepts under prototypic accident conditions. This report summarizes progress made at Oak Ridge National Laboratory (ORNL) and Los Alamos National Laboratory (LANL) in FY13 toward these goals. Alternative fuel cladding materials to Zircaloy for accident tolerance and a significantly extended safety margin requires oxidation resistance to steam or steam-H2 environments at ≥1200°C for short times. At ORNL, prior work focused attention on SiC, FeCr and FeCrAl as the most promising candidates for further development. Also, it was observed that elevated pressure and H2 additions had minor effects on alloy steam oxidation resistance, thus, 1 bar steam was adequate for screening potential candidates. Commercial Fe-20Cr-5Al alloys remain protective up to 1475°C in steam and CVD SiC up to 1700°C in steam. Alloy development has focused on Fe-Cr-Mn-Si-Y and Fe-Cr-Al-Y alloys with the aluminaforming alloys showing more promise. At 1200°C, ferritic binary Fe-Cr alloys required ≥25% Cr to be protective for this application. With minor alloy additions to Fe-Cr, more than 20%Cr was still required, which makes the alloy susceptible to α’ embrittlement. Based on current results, a Fe-15Cr-5Al-Y composition was selected for initial tube fabrication and welding for irradiation experiments in FY14. Evaluations of chemical vapor deposited (CVD) SiC were conducted up to 1700°C in steam. The reaction of H2O with the alumina reaction tube at 1700°C resulted in Al(OH)3

  2. LIQUID BIO-FUEL PRODUCTION FROM NON-FOOD BIOMASS VIA HIGH TEMPERATURE STEAM ELECTROLYSIS

    Energy Technology Data Exchange (ETDEWEB)

    G. L. Hawkes; J. E. O' Brien; M. G. McKellar

    2011-11-01

    Bio-Syntrolysis is a hybrid energy process that enables production of synthetic liquid fuels that are compatible with the existing conventional liquid transportation fuels infrastructure. Using biomass as a renewable carbon source, and supplemental hydrogen from high-temperature steam electrolysis (HTSE), bio-syntrolysis has the potential to provide a significant alternative petroleum source that could reduce US dependence on imported oil. Combining hydrogen from HTSE with CO from an oxygen-blown biomass gasifier yields syngas to be used as a feedstock for synthesis of liquid transportation fuels via a Fischer-Tropsch process. Conversion of syngas to liquid hydrocarbon fuels, using a biomass-based carbon source, expands the application of renewable energy beyond the grid to include transportation fuels. It can also contribute to grid stability associated with non-dispatchable power generation. The use of supplemental hydrogen from HTSE enables greater than 90% utilization of the biomass carbon content which is about 2.5 times higher than carbon utilization associated with traditional cellulosic ethanol production. If the electrical power source needed for HTSE is based on nuclear or renewable energy, the process is carbon neutral. INL has demonstrated improved biomass processing prior to gasification. Recyclable biomass in the form of crop residue or energy crops would serve as the feedstock for this process. A process model of syngas production using high temperature electrolysis and biomass gasification is presented. Process heat from the biomass gasifier is used to heat steam for the hydrogen production via the high temperature steam electrolysis process. Oxygen produced form the electrolysis process is used to control the oxidation rate in the oxygen-blown biomass gasifier. Based on the gasifier temperature, 94% to 95% of the carbon in the biomass becomes carbon monoxide in the syngas (carbon monoxide and hydrogen). Assuming the thermal efficiency of the power

  3. LIQUID BIO-FUEL PRODUCTION FROM NON-FOOD BIOMASS VIA HIGH TEMPERATURE STEAM ELECTROLYSIS

    Energy Technology Data Exchange (ETDEWEB)

    G. L. Hawkes; J. E. O' Brien; M. G. McKellar

    2011-11-01

    Bio-Syntrolysis is a hybrid energy process that enables production of synthetic liquid fuels that are compatible with the existing conventional liquid transportation fuels infrastructure. Using biomass as a renewable carbon source, and supplemental hydrogen from high-temperature steam electrolysis (HTSE), bio-syntrolysis has the potential to provide a significant alternative petroleum source that could reduce US dependence on imported oil. Combining hydrogen from HTSE with CO from an oxygen-blown biomass gasifier yields syngas to be used as a feedstock for synthesis of liquid transportation fuels via a Fischer-Tropsch process. Conversion of syngas to liquid hydrocarbon fuels, using a biomass-based carbon source, expands the application of renewable energy beyond the grid to include transportation fuels. It can also contribute to grid stability associated with non-dispatchable power generation. The use of supplemental hydrogen from HTSE enables greater than 90% utilization of the biomass carbon content which is about 2.5 times higher than carbon utilization associated with traditional cellulosic ethanol production. If the electrical power source needed for HTSE is based on nuclear or renewable energy, the process is carbon neutral. INL has demonstrated improved biomass processing prior to gasification. Recyclable biomass in the form of crop residue or energy crops would serve as the feedstock for this process. A process model of syngas production using high temperature electrolysis and biomass gasification is presented. Process heat from the biomass gasifier is used to heat steam for the hydrogen production via the high temperature steam electrolysis process. Oxygen produced form the electrolysis process is used to control the oxidation rate in the oxygen-blown biomass gasifier. Based on the gasifier temperature, 94% to 95% of the carbon in the biomass becomes carbon monoxide in the syngas (carbon monoxide and hydrogen). Assuming the thermal efficiency of the power

  4. Chemical characteristics and enzymatic saccharification of lignocellulosic biomass treated using high-temperature saturated steam: comparison of softwood and hardwood.

    Science.gov (United States)

    Asada, Chikako; Sasaki, Chizuru; Hirano, Takeshi; Nakamura, Yoshitoshi

    2015-04-01

    This study investigated the effect of high-temperature saturated steam treatments on the chemical characteristics and enzymatic saccharification of softwood and hardwood. The weight loss and chemical modification of cedar and beech wood pieces treated at 25, 35, and 45 atm for 5 min were determined. Fourier transform infrared and X-ray diffraction analyses indicated that solubilization and removal of hemicellulose and lignin occurred by the steam treatment. The milling treatment of steam-treated wood enhanced its enzymatic saccharification. Maximum enzymatic saccharification (i.e., 94% saccharification rate of cellulose) was obtained using steam-treated beech at 35 atm for 5 min followed by milling treatment for 1 min. However, the necessity of the milling treatment for efficient enzymatic saccharification is dependent on the wood species.

  5. Effect of Gas/Steam Turbine Inlet Temperatures on Combined Cycle Having Air Transpiration Cooled Gas Turbine

    Science.gov (United States)

    Kumar, S.; Singh, O.

    2012-10-01

    Worldwide efforts are being made for further improving the gas/steam combined cycle performance by having better blade cooling technology in topping cycle and enhanced heat recovery in bottoming cycle. The scope of improvement is possible through turbines having higher turbine inlet temperatures (TITs) of both gas turbine and steam turbine. Literature review shows that a combined cycle with transpiration cooled gas turbine has not been analyzed with varying gas/steam TITs. In view of above the present study has been undertaken for thermodynamic study of gas/steam combined cycle with respect to variation in TIT in both topping and bottoming cycles, for air transpiration cooled gas turbine. The performance of combined cycle with dual pressure heat recovery steam generator has been evaluated for different cycle pressure ratios (CPRs) varying from 11 to 23 and the selection diagrams presented for TIT varying from 1,600 to 1,900 K. Both the cycle efficiency and specific work increase with TIT for each pressure ratio. For each TIT there exists an optimum pressure ratio for cycle efficiency and specific work. For the CPR of 23 the best cycle performance is seen at a TIT of 1,900 K for maximum steam temperature of 570 °C, which gives the cycle efficiency of 60.9 % with net specific work of 909 kJ/kg.

  6. Recycling of automobile shredder residue with a microwave pyrolysis combined with high temperature steam gasification.

    Science.gov (United States)

    Donaj, Pawel; Yang, Weihong; Błasiak, Włodzimierz; Forsgren, Christer

    2010-10-15

    Presently, there is a growing need for handling automobile shredder residues--ASR or "car fluff". One of the most promising methods of treatment ASR is pyrolysis. Apart of obvious benefits of pyrolysis: energy and metals recovery, there is serious concern about the residues generated from that process needing to be recycled. Unfortunately, not much work has been reported providing a solution for treatment the wastes after pyrolysis. This work proposes a new system based on a two-staged process. The ASR was primarily treated by microwave pyrolysis and later the liquid and solid products become the feedstock for the high temperature gasification process. The system development is supported within experimental results conducted in a lab-scale, batch-type reactor at the Royal Institute of Technology (KTH). The heating rate, mass loss, gas composition, LHV and gas yield of producer gas vs. residence time are reported for the steam temperature of 1173 K. The sample input was 10 g and the steam flow rate was 0.65 kg/h. The conversion reached 99% for liquids and 45-55% for solids, dependently from the fraction. The H(2):CO mol/mol ratio varied from 1.72 solids and 1.4 for liquid, respectively. The average LHV of generated gas was 15.8 MJ/Nm(3) for liquids and 15 MJ/Nm(3) for solids fuels.

  7. Multitechnique characterisation of 304L surface states oxidised at high temperature in steam and air atmospheres

    Science.gov (United States)

    Mamede, Anne-Sophie; Nuns, Nicolas; Cristol, Anne-Lise; Cantrel, Laurent; Souvi, Sidi; Cristol, Sylvain; Paul, Jean-François

    2016-04-01

    In case of a severe accident occurring in a nuclear reactor, surfaces of the reactor coolant system (RCS), made of stainless steel (304L) rich in Cr (>10%) and Ni (8-12%), are oxidised. Fission products (FPs) are released from melt fuel and flow through the RCS. A part of them is deposited onto surfaces either by vapour condensation or by aerosol deposition mechanisms. To be able to understand the nature of interactions between these FPs and the RCS surfaces, a preliminary step is to characterize the RSC surface states in steam and air atmosphere at high temperatures. Pieces of 304L stainless steel have been treated in a flow reactor at two different temperatures (750 °C and 950 °C) for two different exposition times (24 h and 72 h). After surfaces analysing by a unique combination of surface analysis techniques (XPS, ToF-SIMS and LEIS), for 304L, the results show a deep oxide scale with multi layers and the outer layer is composed of chromium and manganese oxides. Oxide profiles differ in air or steam atmosphere. Fe2O3 oxide is observed but in minor proportion and in all cases no nickel is detected near the surface. Results obtained are discussed and compared with the literature data.

  8. Temperature effects in supercritical fluid chromatography: a trade-off between viscous heating and decompression cooling.

    Science.gov (United States)

    De Pauw, Ruben; Choikhet, Konstantin; Desmet, Gert; Broeckhoven, Ken

    2014-10-24

    The study of radial and axial temperature profiles always has been an area interest both in liquid chromatography (LC) and supercritical fluid chromatography (SFC). Whereas in LC always an increase in temperature is observed due to the dominance of viscous heating, in SFC, especially for low modifier content, a decrease in temperature is found due to the much larger decompression cooling. However, for higher modifier content and higher operating pressure, the temperature effects become a trade-off between viscous heating and decompression cooling, since in SFC the latter is a strong function of operating pressure and mobile phase composition. At a temperature of 40°C and for neat CO2, the effect of decompression cooling and viscous heating cancel each other out at a pressure 450bar. This pressure decreases almost linearly with volume fraction of methanol to 150bar at 25vol%. As a result, both cooling and heating effects can be observed when operating at high back pressure, large column pressure drops or high modifier content. For example at a back pressure of 150bar and a column pressure drop of 270bar decompression cooling is observed throughout the column. However at 300bar back pressure and the same pressure drop, the mobile phase heats up in the first part of the column due to viscous heating and then cools in the second part due to decompression cooling. When coupling columns (2.1mm×150mm, 1.8μm fully porous particles) at very high operating pressure (e.g. 750bar for 8vol%), the situation is even more complex. E.g. at a back pressure of 150bar and using 8vol% methanol, viscous heating is only observed in the first column whereas only decompression cooling in the second. Further increasing the inlet pressure up to 1050bar resulted in no excessive temperature differences along the column. This implies that the inlet pressure of SFC instrumentation could be expanded above 600bar without additional band broadening caused by excessive radial temperature

  9. Valve Assembly Technology of 660 MW Ultra-supercritical Double-reheat Steam Turbine%660 MW超超临界二次再热汽轮机阀门装配技术

    Institute of Scientific and Technical Information of China (English)

    张桂明; 胡开吉

    2016-01-01

    文章就公司自主开发的660 MW二次再热机组的阀门装配技术进行介绍。针对阀门的结构特点,详细介绍了其装配工艺流程、阀芯及阀盖部件的安装,文章内容将为同类型阀门的安装提供有益的借鉴。%This paper introduced the valve assembly technology of 660 MW ultra-supercritical double-reheat steam turbine indepen⁃dent researched and developed by Dongfang Turbine Co.,Ltd.(abbreviate DTC). For the valve design feature, the valve assembly pro⁃cess,valve core and valve seat installation were detailedly introduced. The paper can provide helpful reference for homotype valve as⁃sembly.

  10. MULTI-OBJECTIVE PID CONTROLLER BASED ON ADAPTIVE WEIGHTED PSO WITH APPLICATION TO STEAM TEMPERATURE CONTROL IN BOILERS

    Directory of Open Access Journals (Sweden)

    C.Agees Kumar

    2010-07-01

    Full Text Available PID controller is widely used for main steam temperature control of boiler unit in thermal power plant. To avoid the drawback of current PID design methods, this paper presents a new design method for multi-objective PID controller to synthetically consider system requirement in reliability and robustness. Adaptive weighted PSO (AWPSO technique is applied to the parameter optimization design. The optimization problem considered is highly nonlinear, complex, with multiple objectives and constraints. The simulation results on an actual main steam temperature control system indicate that, the multi-objective PID controller designed by presented method, can improve the dynamic performance of main steam temperature control system, with good robustness ability.

  11. Sensitivity Analysis of Fuel Centerline Temperatures in SuperCritical Water-cooled Reactors (SCWRs)

    Science.gov (United States)

    Abdalla, Ayman

    SuperCritical Water-cooled Reactors (SCWRs) are one of the six nuclear-reactor concepts currently being developed under the Generation-IV International Forum (GIF). A main advantage of SCW Nuclear Power Plants (NPPs) is that they offer higher thermal efficiencies compared to those of current conventional NPPs. Unlike today's conventional NPPs, which have thermal efficiencies between 30 - 35%, SCW NPPs will have thermal efficiencies within a range of 45 - 50%, owing to high operating temperatures and pressures (i.e., coolant temperatures as high as 625°C at 25 MPa pressure). The use of current fuel bundles with UO2 fuel at the high operating parameters of SCWRs may cause high fuel centerline temperatures, which could lead to fuel failure and fission gas release. Studies have shown that when the Variant-20 (43-element) fuel bundle was examined at SCW conditions, the fuel centerline temperature industry limit of 1850°C for UO2 and the sheath temperature design limit of 850°C might be exceeded. Therefore, new fuel-bundle designs, which comply with the design requirements, are required for future use in SCWRs. The main objective of this study to conduct a sensitivity analysis in order to identify the main factors that leads to fuel centerline temperature reduction. Therefore, a 54-element fuel bundle with smaller diameter of fuel elements compared to that of the 43-element bundle was designed and various nuclear fuels are examined for future use in a generic Pressure Tube (PT) SCWR. The 54-element bundle consists of 53 heated fuel elements with an outer diameter of 9.5 mm and one central unheated element of 20-mm outer diameter which contains burnable poison. The 54-element fuel bundle has an outer diameter of 103.45 mm, which is the same as the outer diameter of the 43-element fuel bundle. After developing the 54-element fuel bundle, one-dimensional heat-transfer analysis was conducted using MATLAB and NIST REFPROP programs. As a result, the Heat Transfer

  12. Non-syngas direct steam reforming of methanol to hydrogen and carbon dioxide at low temperature.

    Science.gov (United States)

    Yu, Kai Man Kerry; Tong, Weiyi; West, Adam; Cheung, Kevin; Li, Tong; Smith, George; Guo, Yanglong; Tsang, Shik Chi Edman

    2012-01-01

    A non-syngas direct steam reforming route is investigated for the conversion of methanol to hydrogen and carbon dioxide over a CuZnGaO(x) catalyst at 150-200 °C. This route is in marked contrast with the conventional complex route involving steam reformation to syngas (CO/H2) at high temperature, followed by water gas shift and CO cleanup stages for hydrogen production. Here we report that high quality hydrogen and carbon dioxide can be produced in a single-step reaction over the catalyst, with no detectable CO (below detection limit of 1 ppm). This can be used to supply proton exchange membrane fuel cells for mobile applications without invoking any CO shift and cleanup stages. The working catalyst contains, on average, 3-4 nm copper particles, alongside extremely small size of copper clusters stabilized on a defective ZnGa2O4 spinel oxide surface, providing hydrogen productivity of 393.6 ml g(-1)-cat h(-1) at 150 °C.

  13. Experimental design, operation, and results of a 4 kW high temperature steam electrolysis experiment

    Science.gov (United States)

    Zhang, Xiaoyu; O'Brien, James E.; Tao, Greg; Zhou, Can; Housley, Gregory K.

    2015-11-01

    High temperature steam electrolysis (HTSE) is a promising technology for large-scale hydrogen production. However, research on HTSE performance above the kW level is limited. This paper presents the results of 4 kW HTSE long-term test completed in a multi-kW test facility recently developed at the Idaho National Laboratory (INL). The 4 kW HTSE unit consisted of two solid oxide electrolysis stacks electrically connected in parallel, each of which included 40 electrode-supported planar cells. A current density of 0.41 A cm-2 was used for the long-term operating at a constant current mode, resulting in a theoretical hydrogen production rate about 23 slpm. A demonstration of 830 h stable operation was achieved with a degradation rate of 3.1% per 1000 h. The paper also includes detailed descriptions of the piping layout, steam generation and delivery system, test fixture, heat recuperation system, hot zone, instrumentation, and operating conditions. This successful demonstration of multi-kW scale HTSE unit will help to advance the technology toward near-term commercialization.

  14. Low-temperature steam-reforming of ethanol over ZnO-supported Ni and Cu catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Homs, Narcis; Llorca, Jordi; De la Piscina, Pilar Ramirez [Departament de Quimica Inorganica, Universitat de Barcelona, C/Marti i Franques 1-11, 08028 Barcelona (Spain)

    2006-08-15

    ZnO-supported Ni and Cu as well as bimetallic Co-Ni and Co-Cu catalysts containing ca. 0.7wt% sodium promoter and prepared by the co-precipitation method were tested in the ethanol steam-reforming reaction at low temperature (523-723K), using a bioethanol-like mixture diluted in Ar. Monometallic ZnO-supported Cu or Ni samples do not exhibit good catalytic performance in the steam-reforming of ethanol for hydrogen production. Copper catalyst mainly dehydrogenates ethanol to acetaldehyde, whereas nickel catalyst favours ethanol decomposition. However, the addition of Ni to ZnO-supported cobalt has a positive effect both on the production of hydrogen at low temperature (<573K), and on catalyst stability. Evidence for alloy formation as well as mixed oxides at the microstructural level was found in the bimetallic systems after running the ethanol steam-reforming reaction by HRTEM-EELS. (author)

  15. HVOF coatings for steam oxidation protection

    Energy Technology Data Exchange (ETDEWEB)

    Agueero, A.; Muelas, R.; Gonzalez, V. [Instituto Nacional de Tecnica Aeroespacial (INTA), Area de Materiales Metalicos, Madrid (Spain)

    2008-05-15

    In the context of the European project 'Coatings for Supercritical Steam Cycles' (SUPERCOAT), the use of steam oxidation resistant coatings on currently available ferritic materials with high creep strength but poor oxidation resistance was investigated in order to allow increase in the operating temperature of steam power plants from 550 to 650 C. Among the explored coating techniques for this application, chosen on the basis of being potentially appropriate for coating steam turbine components, High Velocity Oxy Fuel (HVOF) thermal spray has resulted in one of the most successful techniques. Different alloyed materials such as FeCrAl, NiCrSiFeB, FeAl, NiCr and FeCr have been deposited, optimized and tested under flowing steam at 650 C. Characterization of as deposited and tested samples by metallography, SEM-EDS and XRD was carried out. Some of these coatings form protective pure chromium or aluminium oxides exhibiting excellent behaviour for at least 15 000 h of exposure, whereas others form less stable complex mixed oxides which nevertheless grow at considerably slower rates than the oxides formed on uncoated P92 (9 wt%Cr ferritic steel). (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  16. High Temperature Air/Steam Gasification of Biomass Wastes - Stage 1. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Blasiak, Wlodzimierz; Szewczyk, Dariusz; Lucas, Carlos; Rafidi, Nabil; Abeyweera Ruchira; Jansson, Anna; Bjoerkman, Eva [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Materials Science and Engineering

    2003-05-01

    In Jan 2002 the Division of Energy and Furnace Technology started the project High Temperature Air an Steam Gasification (HTAG) of biomass wastes, following the approval made by Swedish Energy Agency. The research proved successful; with the fixed bed updraft gasifier coupled to the highly regenerative preheater equipment able to produce a fuel gas not only from wood pellets but also from wood chips, bark and charcoal with considerably reduced amount of tar. This report provides information on solid biomass conversion into fuel gas as a result of air and steam gasification process performed in a fixed bed updraft gasifier. The first chapter of the report presents the overall objectives and the specific objectives of the work. Chapter 2 summarizes state-of-the-art on the gasification field stating some technical differences between low and high temperature gasification processes. Description and schemes of the experimental test rig are provided in Chapter 3. The equipment used to perform measurements of different sort and that installed in the course of the work is described in Chapter 4. Chapter 5 describes the methodology of experiments conducted whose results were processed and evaluated with help of the scheme of equations presented in Chapter 6, called raw data evaluation. Results of relevant experiments are presented and discussed in Chapter 7. A summary discussion of the tar analysis is presented in Chapter 8. Chapter 9 summarizes the findings of the research work conducted and identifies future efforts to ensure the development of next stage. Final chapter provides a summary of conclusions and recommendations of the work. References are provided at the end of the report. Aimed to assist the understanding of the work done, tables and graphs of experiments conducted, irrespective to their quality, are presented in appendices.

  17. 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

  18. Temperature Control via Affine Nonlinear Systems for Intermediate Point of Supercritical Once-Through Boiler Units

    Directory of Open Access Journals (Sweden)

    Hong Zhou

    2014-01-01

    the PID control. The feed-water flow disturbances are considered in simulations of both of the two control methods. The comparison shows the new method has a better performance with a quicker response time and a smaller overshoot, which demonstrates the potential improvement for the supercritical once-through boiler generation unit control.

  19. Ultra-Supercritical Pressure CFB Boiler Conceptual Design Study

    Energy Technology Data Exchange (ETDEWEB)

    Zhen Fan; Steve Goidich; Archie Robertson; Song Wu

    2006-06-30

    Electric utility interest in supercritical pressure steam cycles has revived in the United States after waning in the 1980s. Since supercritical cycles yield higher plant efficiencies than subcritical plants along with a proportional reduction in traditional stack gas pollutants and CO{sub 2} release rates, the interest is to pursue even more advanced steam conditions. The advantages of supercritical (SC) and ultra supercritical (USC) pressure steam conditions have been demonstrated in the high gas temperature, high heat flux environment of large pulverized coal-fired (PC) boilers. Interest in circulating fluidized bed (CFB) combustion, as an alternative to PC combustion, has been steadily increasing. Although CFB boilers as large as 300 MWe are now in operation, they are drum type, subcritical pressure units. With their sizes being much smaller than and their combustion temperatures much lower than those of PC boilers (300 MWe versus 1,000 MWe and 1600 F versus 3500 F), a conceptual design study was conducted herein to investigate the technical feasibility and economics of USC CFB boilers. The conceptual study was conducted at 400 MWe and 800 MWe nominal plant sizes with high sulfur Illinois No. 6 coal used as the fuel. The USC CFB plants had higher heating value efficiencies of 40.6 and 41.3 percent respectively and their CFB boilers, which reflect conventional design practices, can be built without the need for an R&D effort. Assuming construction at a generic Ohio River Valley site with union labor, total plant costs in January 2006 dollars were estimated to be $1,551/kW and $1,244/kW with costs of electricity of $52.21/MWhr and $44.08/MWhr, respectively. Based on the above, this study has shown that large USC CFB boilers are feasible and that they can operate with performance and costs that are competitive with comparable USC PC boilers.

  20. Detonation cell size measurements in high-temperature hydrogen-air-steam mixtures at the BNL high-temperature combustion facility

    Energy Technology Data Exchange (ETDEWEB)

    Ciccarelli, G.; Ginsberg, T.; Boccio, J.L. [and others

    1997-11-01

    The High-Temperature Combustion Facility (HTCF) was designed and constructed with the objective of studying detonation phenomena in mixtures of hydrogen-air-steam at initially high temperatures. The central element of the HTCF is a 27-cm inner-diameter, 21.3-m long cylindrical test vessel capable of being heating to 700K {+-} 14K. A unique feature of the HTCF is the {open_quotes}diaphragmless{close_quotes} acetylene-oxygen gas driver which is used to initiate the detonation in the test gas. Cell size measurements have shown that for any hydrogen-air-steam mixture, increasing the initial mixture temperature, in the range of 300K to 650K, while maintaining the initial pressure of 0.1 MPa, decreases the cell size and thus makes the mixture more detonable. The effect of steam dilution on cell size was tested in stoichiometric and off-stoichiometric (e.g., equivalence ratio of 0.5) hydrogen-air mixtures. Increasing the steam dilution in hydrogen-air mixtures at 0.1 MPa initial pressure increases the cell size, irrespective of initial temperature. It is also observed that the desensitizing effect of steam diminished with increased initial temperature. A 1-dimensional, steady-state Zel`dovich, von Neumann, Doring (ZND) model, with full chemical kinetics, has been used to predict cell size for hydrogen-air-steam mixtures at different initial conditions. Qualitatively the model predicts the overall trends observed in the measured cell size versus mixture composition and initial temperature and pressure. It was found that the proportionality constant used to predict detonation cell size from the calculated ZND model reaction zone varies between 10 and 100 depending on the mixture composition and initial temperature. 32 refs., 35 figs.

  1. High Temperature Co-electrolysis of Steam and CO2 in an SOC stack: Performance and Durability

    DEFF Research Database (Denmark)

    Chen, Ming; Høgh, Jens Valdemar Thorvald; Nielsen, Jens Ulrik

    2012-01-01

    High temperature electrolysis based on solid oxide electrolysis cells (SOECs) is a very promising technology for energy storage or production of synthetic fuels. By electrolysis of steam, the SOEC provides an efficient way of producing high purity hydrogen and oxygen [1]. Furthermore, the SOEC...... units can be used for co-electrolysis of steam and CO2 to produce synthesis gas (CO+H2), which can be further processed to a variety of synthetic fuels such as methane, methanol or DME [2]. Previously we have shown at stack level that Ni/YSZ electrode supported SOEC cells can be operated at 850 o...

  2. Analysis of Possible Application of High-Temperature Nuclear Reactors to Contemporary Large-Output Steam Power Plants on Ships

    Directory of Open Access Journals (Sweden)

    Kowalczyk T.

    2016-04-01

    Full Text Available This paper is aimed at analysis of possible application of helium to cooling high-temperature nuclear reactor to be used for generating steam in contemporary ship steam-turbine power plants of a large output with taking into account in particular variable operational parameters. In the first part of the paper types of contemporary ship power plants are presented. Features of today applied PWR reactors and proposed HTR reactors are discussed. Next, issues of load variability of the ship nuclear power plants, features of the proposed thermal cycles and results of their thermodynamic calculations in variable operational conditions, are presented.

  3. Aluminium Alloy AA6060 surface treatment with high temperature steam containing chemical additives

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Tabrizian, Naja; Jellesen, Morten S.

    2015-01-01

    The steam treatment process was employed to produce a conversion coating on aluminium alloy AA6060. The changes in microstructure and its effect on corrosion resistance properties were investigated. Various concentrations of KMnO4 containing Ce(NO3)3 was injected into the steam and its effect...... on the formation of steam-based conversion coating was evaluated. The use of Mn-Ce into the steam resulted in incorporation of these species into the conversion coating, which resulted in improved corrosion resistance of the alloy substrate....

  4. Thermodynamic analysis of the efficiency of high-temperature steam electrolysis system for hydrogen production

    Science.gov (United States)

    Mingyi, Liu; Bo, Yu; Jingming, Xu; Jing, Chen

    High-temperature steam electrolysis (HTSE), a reversible process of solid oxide fuel cell (SOFC) in principle, is a promising method for highly efficient large-scale hydrogen production. In our study, the overall efficiency of the HTSE system was calculated through electrochemical and thermodynamic analysis. A thermodynamic model in regards to the efficiency of the HTSE system was established and the quantitative effects of three key parameters, electrical efficiency (η el), electrolysis efficiency (η es), and thermal efficiency (η th) on the overall efficiency (η overall) of the HTSE system were investigated. Results showed that the contribution of η el, η es, η th to the overall efficiency were about 70%, 22%, and 8%, respectively. As temperatures increased from 500 °C to 1000 °C, the effect of η el on η overall decreased gradually and the η es effect remained almost constant, while the η th effect increased gradually. The overall efficiency of the high-temperature gas-cooled reactor (HTGR) coupled with the HTSE system under different conditions was also calculated. With the increase of electrical, electrolysis, and thermal efficiency, the overall efficiencies were anticipated to increase from 33% to a maximum of 59% at 1000 °C, which is over two times higher than that of the conventional alkaline water electrolysis.

  5. Identification of Iron Oxides Qualitatively/Quantitatively Formed during the High Temperature Oxidation of Superalloys in Air and Steam Environments

    Institute of Scientific and Technical Information of China (English)

    M.Siddique; N.Hussain; M.Shafi

    2009-01-01

    Mossbauer spectroscopy has been used to study the morphology of iron oxides formed during the oxidation of superalloys, such as SS-304L (1.4306S), Incoloy-800H, Incoloy-825, UBHA-25L, Sanicro-28 and Inconel-690, at 1200℃ exposed in air and steam environments for 400 h. The basic aim was to identify and compare the iron oxides qualitatively and quantitatively, formed during the oxidation of these alloys in two environments. The behaviour of alloy UBHA-25L in high temperature oxidation in both environments indicates that it has good oxidation resistance especially in steam, whereas Sanicro-28 has excellent corrosion resistance in steam environment. In air oxidation of lnconel-690 no iron oxide, with established Mossbauer parameters, was detected.

  6. Supercritical water

    CERN Document Server

    Marcus, Yizhak

    2012-01-01

    Discover the many new and emerging applications of supercritical water as a green solvent Drawing from thousands of original research articles, this book reviews and summarizes what is currently known about the properties and uses of supercritical water. In particular, it focuses on new and emerging applications of supercritical water as a green solvent, including the catalytic conversion of biomass into fuels and the oxidation of hazardous materials. Supercritical Water begins with an introduction that defines supercritical fluids in general. It then defines supercritical wa

  7. Niederaussem电站1000MW超临界汽轮机%1000 MW Supercritical Steam Turbine for the Niederaussem Plant

    Institute of Scientific and Technical Information of China (English)

    Wilfried Ulm; Dale Ernette; John Kern; Ralf M. Bell

    2003-01-01

    本文对Niederaussem K电站汽轮机的初始运行情况展开讨论,并对已使用的最新技术进行了详细的论述.%This paper will discuss the details of this latest technology as well as the initial operating experience of the Niederaussem K steam turbine.

  8. Study on Water Hammer Suppression of Pipeline in Opening Process of Ultra-supercritical Steam Trap%超(超)临界疏水阀开启过程管道水锤抑制研究

    Institute of Scientific and Technical Information of China (English)

    李树勋; 娄燕鹏; 徐晓刚; 丁强伟

    2016-01-01

    针对超(超)临界疏水阀开启过程中管道水锤振动问题,采用特征线法对阀控管道水锤瞬变模型进行了数值计算,运用 Matlab 求解得到了疏水阀在不同流量特性、不同节流效应下开启时管道中流量和水锤压头的时域曲线。研究表明:选用等百分比流量特性的疏水阀,可以减缓阀开启时阀后管道的水锤现象,同时节流效应对疏水阀开启时阀后管道水锤的影响显著,节流越明显,管道中水锤压头幅值越小,水锤波动趋势也越缓和。研究结果为抑制管路水锤与冲击设计提供理论参考。%Aiming at severe vibration phenomenon of pipe behind the ultra-supercritical steam trap during the valve-opening process,the transient model on water hammer in the pipe was calculated by method of characteristics (MOC).Based on Matlab software,the time domain curves of flow and water hammer pressure head on fluid was obtained in different flow characteristic and different throttling effect for valve.The analyses show that adopting equal percentage flow characteristic about the valve could alle-viate water hammer in the pipe.Moreover,the influences of throttling effect for steam trap on water hammer are obvious,and the more obvious the throttling effect for steam trap,the more relieving water hammer wave and the smaller water hammer pressure head peak.The results provide theoretical references for design of steam trap in preventing water hammer and anti-shock analysis of the fluid on pipeline.

  9. Instrumental system for the quick relief of surface temperatures in fumaroles fields and steam heated soils

    Science.gov (United States)

    Diliberto, Iole; Cappuzzo, Santo; Inguaggiato, Salvatore; Cosenza, Paolo

    2014-05-01

    We present an instrumental system to measure and to map the space variation of the surface temperature in volcanic fields. The system is called Pirogips, its essential components are a Pyrometer and a Global Position System but also other devices useful to obtain a good performance of the operating system have been included. In the framework of investigation to define and interpret volcanic scenarios, the long-term monitoring of gas geochemistry can improve the resolution of the scientific approaches by other specific disciplines. Indeed the fluid phase is released on a continuous mode from any natural system which produces energy in excess respect to its geological boundaries. This is the case of seismic or magmatic active areas where the long-term geochemical monitoring is able to highlight, and to follow in real time, changes in the rate of energy release and/or in the feeding sources of fluids, thus contributing to define the actual behaviour of the investigated systems (e.g. Paonita el al., 2013; 2002; Taran, 2011; Zettwood and Tazieff, 1973). The demand of pirogips starts from the personal experience in long term monitoring of gas geochemistry (e.g. Diliberto I.S, 2013; 2011; et al., 2002; Inguaggiato et al.,2012a, 2012b). Both space and time variation of surface temperature highlight change of energy and mass release from the deep active system, they reveal the upraise of deep and hot fluid and can be easily detected. Moreover a detailed map of surface temperature can be very useful for establishing a network of sampling points or installing a new site for geochemical monitoring. Water is commonly the main component of magmatic or hydrothermal fluid release and it can reach the ground surface in the form of steam, as in the high and low temperature fumaroles fields, or it can even condense just below the ground surface. In this second case the water disperses in pores or circulates in the permeable layers while the un-condensable gases reach the surface (e

  10. Validation of low-temperature steam with formaldehyde sterilization for endoscopes, using validation device.

    Science.gov (United States)

    Kanemitsu, Keiji; Ogawa, Akihisa; Hatori, Tsuruo; Imasaka, Takayuki; Kunishima, Hiroyuki; Inden, Ken; Hatta, Masumitsu; Nakamura, Ichiro; Hirayama, Yoshihiro; Kaku, Mitsuo

    2005-12-01

    Validation of sterilization is an important step before clinical use of medical equipment. Adequate validation of sterilization of the endoscope has not been reported. One reason for this is the lack of suitable devices for validation. The VDES (validation device for endoscope sterilization; Olympus prototype model, Olympus, Tokyo, Japan) was designed in two types (type A and type B) and resembles gastroscopes and duodenoscopes, respectively. Each type consists of inner and outer tubing and a central capsule containing a biological indicator. The device was designed to examine the effectiveness of low-temperature sterilizers, such as ethylene oxide gas, hydrogen peroxide gas plasma, and low-temperature steam with formaldehyde (LTSF) sterilizer. The aim of this study was to validate the sterilization of GI endoscopes by the LTSF sterilizer. Sterilization was assessed using both types of VDES after a 60-min application of LTSF. Culture of the biological indicator confirmed the complete eradication of the bacteria in a total of 10 experiments with each type of VDES after LTSF sterilization. Our results confirm that the LTSF sterilizer may sterilize endoscopes currently distributed by Olympus. Commercialization of VDES will make it possible to evaluate the reliability of sterilization when it is set in the sterilization device with endoscopes.

  11. Interpretation of biomass gasification yields regarding temperature intervals under nitrogen-steam atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Haykiri-Acma, H.; Yaman, S. [Istanbul Technical University, Chemical and Metallurgical Engineering Faculty, Chemical Engineering Department, 34469 Maslak, Istanbul (Turkey)

    2007-04-15

    Gasification of some agricultural waste biomass samples (sunflower shell, pine cone, cotton refuse, and olive refuse) and colza seed was performed using a thermogravimetric analyzer at temperatures up to 1273 K with a constant heating rate of 20 K/min under a dynamic nitrogen-steam atmosphere. Derivative thermogravimetric analysis profiles of the samples were derived from the non-isothermal thermogravimetric analysis data. Gasification yields of the biomass samples at temperature intervals of 473-553 K, 553-653 K, 653-773 K, 773-973 K, and 973-1173 K were investigated considering the successive stages of ''evolution of carbon oxides'', ''start of hydrocarbon evolution'', ''evolution of hydrocarbons'', ''dissociation'', and ''evolution of hydrogen'', respectively. Although, there were some interactions between these stages, some evident relations were observed between the gasification yields in a given stage and the chemical properties of the parent biomass materials. (author)

  12. Steam Temperature Control Strategy of F Class HRSG%F 级余热锅炉蒸汽温度控制策略

    Institute of Scientific and Technical Information of China (English)

    薛丽华; 章禔; 徐健

    2013-01-01

    Based on heat recovery steam generator which form a complete set for 9FA gas turbine, this paper introduces the characteris-tic and steam attemperator arrangements of F class heat recovery steam generator , the gas turbine and steam turbine combined cycle steam control strategy of main steam , HPⅡsuperheater outlet steam and reheat steam;also introduces implementation method of su-perheat protection and minimum flow protection .Inlet guide vane participate in temperature control of gas turbine exhaust during unit start up, to stabilize main steam temperature , utilizing inlet guide vane angle feedforward .%以9 FA燃气轮机配套的余热锅炉为例,介绍了F级余热锅炉特点及蒸汽减温配置,主蒸汽温度、二级高压过热器出口温度及再热蒸汽温度的控制策略,过热度保护和最小流量保护的实现方法。机组启动阶段, IGV参与燃气轮机排气温度控制,此时采用IGV角度前馈来稳定启动期间的主蒸汽温度。

  13. Development of computational methods for the safety assessment of gas-cooled high-temperature and supercritical light-water reactors. Final report; Rechenmethoden zur Bewertung der Sicherheit von gasgekuehlten Hochtemperaturreaktoren und superkritischen Leichtwasserreaktoren. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, S.; Cron, D. von der; Hristov, H.; Lerchl, G.; Papukchiev, A.; Seubert, A.; Sureda, A.; Weis, J.; Weyermann, F.

    2012-12-15

    This report documents developments and results in the frame of the project RS1191 ''Development of computational methods for the safety assessment of gas-cooled high temperature and supercritical light-water reactors''. The report is structured according to the five work packages: 1. Reactor physics modeling of gas-cooled high temperature reactors; 2. Coupling of reactor physics and 3-D thermal hydraulics for the core barrel; 3. Extension of ATHLET models for application to supercritical reactors (HPLWR); 4. Further development of ATHLET for application to HTR; 5. Further development and validation of ANSYS CFX for application to alternative reactor concepts. Chapter 4 describes the extensions made in TORT-TD related to the simulation of pebble-bed HTR, e.g. spectral zone buckling, Iodine-Xenon dynamics, nuclear decay heat calculation and extension of the cross section interpolation algorithms to higher dimensions. For fast running scoping calculations, a time-dependent 3-D diffusion solver has been implemented in TORT-TD. For the PBMR-268 and PBMR-400 as well as for the HTR-10 reactor, appropriate TORT-TD models have been developed. Few-group nuclear cross sections have been generated using the spectral codes MICROX- 2 and DRAGON4. For verification and validation of nuclear cross sections and deterministic reactor models, MCNP models of reactor core and control rod of the HTR-10 have been developed. Comparisons with experimental data have been performed for the HTR-10 first criticality and control rod worth. The development of the coupled 3-D neutron kinetics and thermal hydraulics code system TORT-TD/ATTICA3D is documented in chapter 5. Similar to the couplings with ATHLET and COBRA-TF, the ''internal'' coupling approach has been implemented. Regarding the review of experiments and benchmarks relevant to HTR for validation of the coupled code system, the PBMR-400 benchmarks and the HTR-10 test reactor have been selected

  14. Highly loaded Ni-based catalysts for low temperature ethanol steam reforming

    Science.gov (United States)

    Wang, Tuo; Ma, Hongyan; Zeng, Liang; Li, Di; Tian, Hao; Xiao, Shengning; Gong, Jinlong

    2016-05-01

    This paper describes the design of high-loading Ni/Al2O3 catalysts (78 wt% Ni) for low temperature ethanol steam reforming. The catalysts were synthesized via both co-precipitation (COP) and impregnation (IMP) methods. All the catalysts were measured by N2 adsorption-desorption, XRD, H2-TPR, and H2 pulse chemisorption. The characterization results demonstrated that the preparation method and the loading significantly affected the nickel particle size, active nickel surface area and catalytic performance. Over COP catalysts, large nickel particles were presented in nickel aluminum mixed oxides. In comparison, IMP catalysts gained more ``free'' NiO particles with weak interaction with the aluminum oxide. Consequently, COP catalysts yielded smaller nickel particles and larger active nickel surface areas than those of IMP catalysts. High loading is beneficial for obtaining sufficient active nickel sites when nickel particles are dispersed via COP, whereas excessive nickel content is not desired for catalysts prepared by IMP. Specifically, the 78 wt% nickel loaded catalyst synthesized by COP possessed small nickel particles (~6.0 nm) and an abundant active nickel area (35.1 m2 gcat-1). Consequently, COP-78 achieved superior stability with 92% ethanol conversion and ~35% H2 selectivity at 673 K for 30 h despite the presence of a considerable amount of coke.

  15. Advanced Signal Processing for High Temperatures Health Monitoring of Condensed Water Height in Steam Pipes

    Science.gov (United States)

    Lih, Shyh-Shiuh; Bar-Cohen, Yoseph; Lee, Hyeong Jae; Takano, Nobuyuki; Bao, Xiaoqi

    2013-01-01

    An advanced signal processing methodology is being developed to monitor the height of condensed water thru the wall of a steel pipe while operating at temperatures as high as 250deg. Using existing techniques, previous study indicated that, when the water height is low or there is disturbance in the environment, the predicted water height may not be accurate. In recent years, the use of the autocorrelation and envelope techniques in the signal processing has been demonstrated to be a very useful tool for practical applications. In this paper, various signal processing techniques including the auto correlation, Hilbert transform, and the Shannon Energy Envelope methods were studied and implemented to determine the water height in the steam pipe. The results have shown that the developed method provides a good capability for monitoring the height in the regular conditions. An alternative solution for shallow water or no water conditions based on a developed hybrid method based on Hilbert transform (HT) with a high pass filter and using the optimized windowing technique is suggested. Further development of the reported methods would provide a powerful tool for the identification of the disturbances of water height inside the pipe.

  16. Hydrogen from biomass gas steam reforming for low temperature fuel cell: energy and exergy analysis

    Directory of Open Access Journals (Sweden)

    A. Sordi

    2009-03-01

    Full Text Available This work presents a method to analyze hydrogen production by biomass gasification, as well as electric power generation in small scale fuel cells. The proposed methodology is the thermodynamic modeling of a reaction system for the conversion of methane and carbon monoxide (steam reforming, as well as the energy balance of gaseous flow purification in PSA (Pressure Swing Adsorption is used with eight types of gasification gases in this study. The electric power is generated by electrochemical hydrogen conversion in fuel cell type PEMFC (Proton Exchange Membrane Fuel Cell. Energy and exergy analyses are applied to evaluate the performance of the system model. The simulation demonstrates that hydrogen production varies with the operation temperature of the reforming reactor and with the composition of the gas mixture. The maximum H2 mole fraction (0.6-0.64 mol.mol-1 and exergetic efficiency of 91- 92.5% for the reforming reactor are achieved when gas mixtures of higher quality such as: GGAS2, GGAS4 and GGAS5 are used. The use of those gas mixtures for electric power generation results in lower irreversibility and higher exergetic efficiency of 30-30.5%.

  17. High Temperature Steam Electrolysis Materials Degradation: Preliminary Results of Corrosion Tests on Ceramatec Electrolysis Cell Components

    Energy Technology Data Exchange (ETDEWEB)

    Paul Demkowicz; Prateek Sachdev; Kevin DeWall; Pavel Medvedev

    2007-06-01

    Corrosion tests were performed on stainless steel and nickel alloy coupons in H2O/H2 mixtures and dry air to simulate conditions experienced in high temperature steam electrolysis systems. The stainless steel coupons were tested bare and with one of three different proprietary coatings applied. Specimens were corroded at 850°C for 500 h with weight gain data recorded at periodic intervals. Post-test characterization of the samples included surface and cross-section scanning electron microscopy, grazing incidence x-ray diffraction, and area-specific resistance measurements. The uncoated nickel alloy outperformed the ferritic stainless steel under all test conditions based on weight gain data. Parabolic rate constants for corrosion of these two uncoated alloys were consistent with values presented in the literature under similar conditions. The steel coatings reduced corrosion rates in H2O/H2 mixtures by as much as 50% compared to the untreated steel, but in most cases showed negligible corrosion improvement in air. The use of a rare-earth-based coating on stainless steel did not result in a significantly different area specific resistance values after corrosion compared to the untreated alloy. Characterization of the samples is still in progress and the findings will be revised when the complete data set is available.

  18. Steam generators secondary side chemical cleaning at Point Lepreau using the Siemens high temperature process

    Energy Technology Data Exchange (ETDEWEB)

    Verma, K.; MacNeil, C. [New Brunswick Power Corp., Lepreau (Canada); Odar, S.; Kuhnke, K. [Siemens AG, Erlangen (Germany)

    1997-02-01

    This paper describes the chemical cleaning of the four steam generators at the Point Lepreau facility, which was accomplished as a part of a normal service outage. The steam generators had been in service for twelve years. Sludge samples showed the main elements were Fe, P and Na, with minor amounts of Ca, Mg, Mn, Cr, Zn, Cl, Cu, Ni, Ti, Si, and Pb, 90% in the form of Magnetite, substantial phosphate, and trace amounts of silicates. The steam generators were experiencing partial blockage of broached holes in the TSPs, and corrosion on tube ODs in the form of pitting and wastage. In addition heat transfer was clearly deteriorating. More than 1000 kg of magnetite and 124 kg of salts were removed from the four steam generators.

  19. 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.

  20. Utilisation of bleed steam heat to increase the upper heat source temperature in low-temperature ORC

    Science.gov (United States)

    Mikielewicz, Dariusz; Mikielewicz, Jarosław

    2011-12-01

    In the paper presented is a novel concept to utilize the heat from the turbine bleed to improve the quality of working fluid vapour in the bottoming organic Rankine cycle (ORC). That is a completely novel solution in the literature, which contributes to the increase of ORC efficiency and the overall efficiency of the combined system of the power plant and ORC plant. Calculations have been accomplished for the case when available is a flow rate of low enthalpy hot water at a temperature of 90 °C, which is used for preliminary heating of the working fluid. That hot water is obtained as a result of conversion of exhaust gases in the power plant to the energy of hot water. Then the working fluid is further heated by the bleed steam to reach 120 °C. Such vapour is subsequently directed to the turbine. In the paper 5 possible working fluids were examined, namely R134a, MM, MDM, toluene and ethanol. Only under conditions of 120 °C/40 °C the silicone oil MM showed the best performance, in all other cases the ethanol proved to be best performing fluid of all. Results are compared with the "stand alone" ORC module showing its superiority.

  1. Protection of zirconium by alumina- and chromia-forming iron alloys under high-temperature steam exposure

    Science.gov (United States)

    Terrani, Kurt A.; Parish, Chad M.; Shin, Dongwon; Pint, Bruce A.

    2013-07-01

    The viability of advanced oxidation-resistant Fe-base alloys to protect zirconium from rapid oxidation in high-temperature steam environments has been examined. Specimens were produced such that outer layers of FeCrAl ferritic alloy and Type 310 austenitic stainless steel were incorporated on the surface of zirconium metal slugs. The specimens were exposed to high-temperature 0.34 MPa steam at 1200 and 1300 °C. The primary degradation mechanism for the protective layer was interdiffusion with the zirconium, as opposed to high-temperature oxidation in steam. The FeCrAl layer experienced less degradation and protected the zirconium at 1300 °C for 8 h. Constituents of the Fe-base alloys rapidly diffused into the zirconium and resulted in the formation of various intermetallic layers at the interface and precipitates inside the bulk zirconium. The nature of this interaction for FeCrAl and 310SS has been characterized by use of microscopic techniques as well as computational thermodynamics. Finally, a reactor physics discussion on the applicability of these protective layers in light-water-reactor nuclear fuel structures is offered.

  2. Ultra high-temperature solids-free insulating packer fluid for oil and gas production, steam injection and geothermal wells

    Energy Technology Data Exchange (ETDEWEB)

    Ezell, R.G.; Harrison, D.J. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[Halliburton Energy Services, Calgary, AB (Canada)

    2008-10-15

    Uncontrolled heat transfer from production/injection tubing during thermal oil recovery via steam injection can be detrimental to the integrity of the casing and to the quality of the steam that is injected into the reservoir. An aqueous-based insulating packer fluid (IPF) was introduced to improve the steam injection process by controlling the total heat loss from the produced fluids to the surrounding wellbore, internal annuli and formation. The IPF was developed for elevated temperature environments through extensive investigation across multidisciplinary technology. The innovative system delivers performance beyond conventional systems of comparable thermal conductivity. Its density range and conductivity measurements were presented in this paper. High-temperature static aging tests showed superior gel integrity without any phase separation after exposure to temperatures higher than 260 degrees C. The new fluids are hydrate inhibitive, non-corrosive and pass oil and grease testing. They are considered to be environmentally sound by Gulf of Mexico standards. It was concluded that the new ultra high-performance insulating packer fluid (HTIPF) reduced the heat loss significantly by both conduction and convection. Heat transfer within the aqueous-based HTIPF was 97 per cent less than that of pure water. It was concluded that the HTIPF can be substituted for conventional packer fluids without compromising any well control issues. 21 refs., 1 tab., 4 figs.

  3. Short-time Oxidation of Alloy 690 in High-temperature and High-pressure Steam and Water

    Institute of Scientific and Technical Information of China (English)

    F. Huang; J.Q. Wang; E.H. Han; W. Ke

    2012-01-01

    The oxidation behavior of alloy 690 exposed to high-temperature and high-pressure steam and water at 280℃ for 1 h was investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). In high-temperature and high-pressure steam, the oxide film is composed of an outermost Ni-rich hydroxides layer, an intermediate layer of hydroxides and oxides enriched in Cr, an inner oxide layer. The film formed in high-temperature water is similar to that in steam, except for missing the Ni-rich hydroxides layer. Samples with different surface finishes (electropolished, mechanically polished, ground, and as-received) were prepared for comparison. A general increase of the oxide thickness with the degree of surface roughness is observed. The equivalent oxide thicknesses lie in the range of 100-200 nm for the as-received samples, 150-250 nm for the samples ground to 400# and 10-20 nm for the samples ground to 1500#, mechanically polished, and electropolished.

  4. 一种太阳能吸热器过热蒸汽温度控制系统%Temperature control system of superheated steam for one type solar water/steam receiver

    Institute of Scientific and Technical Information of China (English)

    郭铁铮; 刘国耀; 刘德有; 郭苏; 许昌

    2012-01-01

    介绍了一种应用于塔式太阳能热发电系统的水/蒸汽吸热器过热蒸汽温度控制系统.受到太阳辐射能间歇性和不确定性的影响,吸热器产生的过热蒸汽温度难于控制.控制系统根据吸热器在蒸汽流量变化、光功率变化和减温水流量变化等3种主要扰动下的过热汽温度动态响应特性,以减温水流量作为控制量,光功率和蒸汽负荷作为前馈信号,设计和研制了两段式过热蒸汽温度控制系统,使吸热器过热区出口汽温维持在允许的范围内.%A superheated steam temperature control system of heat receiver in solar power tower plant was introduced. It is hard to control superheated steam temperature of receiver because solar radiant energy is intermittent and unsteady. A superheated steam temperature control system with two phases was designed and developed based on dynamic response characteristics of superheated steam caused by three main influencing factors such as steam flow, solar radiation and flow of desuperheating water. The flow of desuperheating water was used as control variable, and solar radiation and steam load as feed-forward signal, the steam outlet temperature at superheat zone in receiver changed within allowable arrange.

  5. Enhanced mechanical, thermal, and electric properties of graphene aerogels via supercritical ethanol drying and high-temperature thermal reduction.

    Science.gov (United States)

    Cheng, Yehong; Zhou, Shanbao; Hu, Ping; Zhao, Guangdong; Li, Yongxia; Zhang, Xinghong; Han, Wenbo

    2017-05-03

    Graphene aerogels with high surface areas, ultra-low densities and thermal conductivities have been prepared to exploit their wide applications from pollution adsorption to energy storage, supercapacitor, and thermal insulation. However, the low mechanical properties, poor thermal stability and electric conductivity restrict these aerogels' applications. In this paper, we prepared mechanically strong graphene aerogels with large BET surface areas, low thermal conductivities, high thermal stability and electric conductivities via hydrothermal reduction and supercritical ethanol drying. Annealing at 1500 °C resulted in slightly increased thermal conductivity and further improvement in mechanical properties, oxidation temperature and electric conductivity of the graphene aerogel. The large BET surface areas, together with strong mechanical properties, low thermal conductivities, high thermal stability and electrical conductivities made these graphene aerogels feasible candidates for use in a number of fields covering from batteries to sensors, electrodes, lightweight conductor and insulation materials.

  6. Structural Transition in Supercritical Fluids

    Directory of Open Access Journals (Sweden)

    Boris I. Sedunov

    2011-01-01

    Full Text Available The extension of the saturation curve ( on the PT diagram in the supercritical region for a number of monocomponent supercritical fluids by peak values for different thermophysical properties, such as heat capacities and and compressibility has been studied. These peaks signal about some sort of fluid structural transition in the supercritical region. Different methods give similar but progressively diverging curves st( for this transition. The zone of temperatures and pressures near these curves can be named as the zone of the fluid structural transition. The outstanding properties of supercritical fluids in this zone help to understand the physical sense of the fluid structural transition.

  7. Statistical correlations for thermophysical properties of Supercritical Argon (SCAR) used in cooling of futuristic High Temperature Superconducting (HTS) cables

    Science.gov (United States)

    Kalsia, Mohit; Dondapati, Raja Sekhar; Usurumarti, Preeti Rao

    2017-05-01

    High Temperature Superconducting (HTS) cables are emerging as an alternative to conventional cables in efficient power transmission. However, these HTS cables require cooling below the critical temperature of superconductors used to transmit larger currents. With the invention of high temperature superconductors whose critical temperatures are up to 134 K (Hg based), it is a great challenge to identify a suitable coolant which can carry away the heating load on the superconductors. In order to accomplish such challenge, an attempt has been made in the present work to propose supercritical Argon (SCAR) as the alternative to cool the HTS cables. Further, a statistical correlation has been developed for the thermophysical properties such as density, viscosity, specific heat and thermal conductivity of SCAR. In addition, the accuracy of developed correlations is established with the help of few statistical parameters and validated with standard database available in the literature. These temperature dependent accurate correlations are useful in predicting the pressure drop and heat transfer behaviour in HTS cables using numerical or computational techniques. In recent times, with the sophistication of computer technology, solving of various complex transport equations along with the turbulence models became popular and hence the developed correlations would benefit the technological community. It is observed that, a decrease in pressure, density and viscosity are found to be decreasing whereas the thermal conductivity and specific heat increase significantly. It can be concluded that higher heat transfer rate and lower pumping power can be achieved with SCAR as coolant in the HTS cables.

  8. Ionic Effects on Supercritical CO2-Brine Interfacial Tensions: Molecular Dynamics Simulations and a Universal Correlation with Ionic Strength, Temperature, and Pressure.

    Science.gov (United States)

    Zhao, Lingling; Ji, Jiayuan; Tao, Lu; Lin, Shangchao

    2016-09-13

    For geological CO2 storage in deep saline aquifers, the interfacial tension (IFT) between supercritical CO2 and brine is critical for the storage security and design of the storage capacitance. However, currently, no predictive model exists to determine the IFT of supercritical CO2 against complex electrolyte solutions involving various mixed salt species at different concentrations and compositions. In this paper, we use molecular dynamics (MD) simulations to investigate the effect of salt ions on the incremental IFT at the supercritical CO2-brine interface with respect to that at the reference supercritical CO2-water interface. Supercritical CO2-NaCl solution, CO2-CaCl2 solution and CO2-(NaCl+CaCl2) mixed solution systems are simulated at 343 K and 20 MPa under different salinities and salt compositions. We find that the valence of the cations is the primary contributor to the variation in IFT, while the Lennard-Jones potentials for the cations pose a smaller impact on the IFT. Interestingly, the incremental IFT exhibits a general linear correlation with the ionic strength in the above three electrolyte systems, and the slopes are almost identical and independent of the solution types. Based on this finding, a universal predictive formula for IFTs of CO2-complex electrolyte solution systems is established, as a function of ionic strength, temperature, and pressure. The predicted IFTs using the established formula agree perfectly (with a high statistical confidence level of ∼96%) with a wide range of experimental data for CO2 interfacing with different electrolyte solutions, such as those involving MgCl2 and Na2SO4. This work provides an efficient and accurate route to directly predict IFTs in supercritical CO2-complex electrolyte solution systems for practical engineering applications, such as geological CO2 sequestration in deep saline aquifers and other interfacial systems involving complex electrolyte solutions.

  9. Supercritical Water Reactor Cycle for Medium Power Applications

    Energy Technology Data Exchange (ETDEWEB)

    BD Middleton; J Buongiorno

    2007-04-25

    Scoping studies for a power conversion system based on a direct-cycle supercritical water reactor have been conducted. The electric power range of interest is 5-30 MWe with a design point of 20 MWe. The overall design objective is to develop a system that has minimized physical size and performs satisfactorily over a broad range of operating conditions. The design constraints are as follows: Net cycle thermal efficiency {ge}20%; Steam turbine outlet quality {ge}90%; and Pumping power {le}2500 kW (at nominal conditions). Three basic cycle configurations were analyzed. Listed in order of increased plant complexity, they are: (1) Simple supercritical Rankine cycle; (2) All-supercritical Brayton cycle; and (3) Supercritical Rankine cycle with feedwater preheating. The sensitivity of these three configurations to various parameters, such as reactor exit temperature, reactor pressure, condenser pressure, etc., was assessed. The Thermoflex software package was used for this task. The results are as follows: (a) The simple supercritical Rankine cycle offers the greatest hardware simplification, but its high reactor temperature rise and reactor outlet temperature may pose serious problems from the viewpoint of thermal stresses, stability and materials in the core. (b) The all-supercritical Brayton cycle is not a contender, due to its poor thermal efficiency. (c) The supercritical Rankine cycle with feedwater preheating affords acceptable thermal efficiency with lower reactor temperature rise and outlet temperature. (d) The use of a moisture separator improves the performance of the supercritical Rankine cycle with feedwater preheating and allows for a further reduction of the reactor outlet temperature, thus it was selected for the next step. Preliminary engineering design of the supercritical Rankine cycle with feedwater preheating and moisture separation was performed. All major components including the turbine, feedwater heater, feedwater pump, condenser, condenser pump

  10. Simulation Study on Main Steam Temperature Control Based on Active Disturbance Rejection Controller%基于自抗扰控制器的主蒸汽温度控制仿真研究

    Institute of Scientific and Technical Information of China (English)

    李超

    2013-01-01

    The main steam temperature control object of the supercritical thermal power units with many fea-tures, such as the large lag, strong inertia and strong nonlinear, which is difficult to control as a thermal object. Owing to these characteristics, this paper, by using the guiding before temperature as an auxiliary feedback signal, applies the active disturbance rejection controller (ADRC) in the main circuit, and the PID controller in the secondary circuit, which the two circuits make up the main steam temperature cascade control system based on ADRC-PID. The system is tested on the platform of Simulink in Matlab based on the model of 600WM supercritical thermal power units. The results show that:compared with PID-PID control strategy, ADRC control strategy has a better control of accuracy and quality, especially in the disturbance rejection and the robustness of the system.%超临界火电机组中主汽温度控制系统对象具有大迟延、大惯性以及强非线性等特点,属于较难控制的一类热工对象。针对这些特性,本文以导前汽温作为辅助反馈信号,主回路采用自抗扰控制器(ADRC),副回路采用PID控制器,主副回路构成ADRC-PID主汽温串级控制系统,以600MW超临界机组模型在matlab中Simulink仿真平台下进行试验研究。结果表明,ADRC-PID控制策略与PID-PID控制策略相比具有更高的控制精度和更好的控制品质,尤其体现在系统的抗扰动能力和鲁棒性。

  11. Sustainable valorization of plastic wastes for energy with environmental safety via High-Temperature Pyrolysis (HTP) and High-Temperature Steam Gasification (HTSG).

    Science.gov (United States)

    Kantarelis, E; Donaj, P; Yang, W; Zabaniotou, A

    2009-08-15

    In the present study the energetic valorization of electric cable shredder residues (mixed plastics) has been investigated. Thermochemical conversion by means of High-Temperature Steam Gasification (HTSG) and High-Temperature Pyrolysis (HTP) was studied. The effects of temperature and reaction time--process parameters--were investigated. Comparison of the results showed that HTSG seems a more suitable process in terms of produced syngas quality (64%, v/v and 13MJ/Nm(3)) than HTP because of higher H(2) yield and lower tar content.

  12. Sustainable valorization of plastic wastes for energy with environmental safety via High-Temperature Pyrolysis (HTP) and High-Temperature Steam Gasification (HTSG)

    Energy Technology Data Exchange (ETDEWEB)

    Kantarelis, E. [Department of Chemical Engineering, Aristotle University of Thessaloniki, Un.Box 455, University Campus, GR54124 Thessaloniki (Greece); Donaj, P.; Yang, W. [Royal Institute of Technology (KTH), School of Industrial Engineering and Management, Department of Materials Science and Engineering, Division of Energy and Furnace Technology, SE100 44 Stockholm (Sweden); Zabaniotou, A., E-mail: sonia@cheng.auth.gr [Department of Chemical Engineering, Aristotle University of Thessaloniki, Un.Box 455, University Campus, GR54124 Thessaloniki (Greece)

    2009-08-15

    In the present study the energetic valorization of electric cable shredder residues (mixed plastics) has been investigated. Thermochemical conversion by means of High-Temperature Steam Gasification (HTSG) and High-Temperature Pyrolysis (HTP) was studied. The effects of temperature and reaction time - process parameters - were investigated. Comparison of the results showed that HTSG seems a more suitable process in terms of produced syngas quality (64%, v/v and 13 MJ/Nm{sup 3}) than HTP because of higher H{sub 2} yield and lower tar content.

  13. Statistical correlations for thermophysical properties of Supercritical Argon (SCAR) used in cooling of futuristic High Temperature Superconducting (HTS) cables

    Energy Technology Data Exchange (ETDEWEB)

    Kalsia, Mohit [School of Mechanical Engineering, Lovely Professional University, Phagwara, 144 401 (India); Dondapati, Raja Sekhar, E-mail: drsekhar@ieee.org [School of Mechanical Engineering, Lovely Professional University, Phagwara, 144 401 (India); Usurumarti, Preeti Rao [Department of Mechanical Engineering, PVK Institute of Technology, Anantpur, 515 001 (India)

    2017-05-15

    Highlights: • The developed correlations can be integrated into thermohydraulic analysis of HTS cables. • This work also explains the phenomenon of flow with less pumping power and maximum heat transfer in HTS cables. • Pumping power required to circulate the SCAR for cooling of HTS cables would be significantly lower. • For Hg-based high temperature superconductors (T{sub c} > 134 K), SCAR found to be a suitable coolant. - Abstract: High Temperature Superconducting (HTS) cables are emerging as an alternative to conventional cables in efficient power transmission. However, these HTS cables require cooling below the critical temperature of superconductors used to transmit larger currents. With the invention of high temperature superconductors whose critical temperatures are up to 134 K (Hg based), it is a great challenge to identify a suitable coolant which can carry away the heating load on the superconductors. In order to accomplish such challenge, an attempt has been made in the present work to propose supercritical Argon (SCAR) as the alternative to cool the HTS cables. Further, a statistical correlation has been developed for the thermophysical properties such as density, viscosity, specific heat and thermal conductivity of SCAR. In addition, the accuracy of developed correlations is established with the help of few statistical parameters and validated with standard database available in the literature. These temperature dependent accurate correlations are useful in predicting the pressure drop and heat transfer behaviour in HTS cables using numerical or computational techniques. In recent times, with the sophistication of computer technology, solving of various complex transport equations along with the turbulence models became popular and hence the developed correlations would benefit the technological community. It is observed that, a decrease in pressure, density and viscosity are found to be decreasing whereas the thermal conductivity and specific

  14. Experimental study on temperature distribution of membrane water wall in an ultra-supercritical pressure once-through boiler burning zhundong coal

    Science.gov (United States)

    He, Honghao; Li, Wenjun; Zeng, Jun; Xie, Guohong; Peng, Min; Duan, Xuenong

    2017-05-01

    Taking an ultra-supercritical pressure once-through boiler as an example, the temperature distribution of the lower membrane water wall is investigated experimentally, the conclusion reveals that increasing the proportion of Zhundong coal can effectively reduce the district heat load, which benefits the temperature uniformity in the lower membrane water wall. When the boiler being operated at middle load, the temperature deviation in lower membrane water wall increase simultaneously, one of the reasons is that the restriction orifice could not adjust the flow rate of working fluid as expected. By adjusting boiler performance, the temperature uniformity of lower membrane water wall can be improved to a certain degree.

  15. Supercritical solvent coal extraction

    Science.gov (United States)

    Compton, L. E. (Inventor)

    1984-01-01

    Yields of soluble organic extract are increased up to about 50% by the supercritical extraction of particulate coal at a temperature below the polymerization temperature for coal extract fragments (450 C.) and a pressure from 500 psig to 5,000 psig by the conjoint use of a solvent mixture containing a low volatility, high critical temperature coal dissolution catalyst such as phenanthrene and a high volatility, low critical temperature solvent such as toluene.

  16. Coupling of Wind Energy and Biogas with a High Temperature Steam Electrolyser for Hydrogen and Methane Production

    OpenAIRE

    Monnerie, Nathalie; Roeb, Martin; Houaijia, Anis; Sattler, Christian

    2014-01-01

    The production of environment friendly green fuels is based on energy from renewable sources. Among the renewable sources, wind power is a very growing power technology. An example which has been discussed very widely is hydrogen which is an ideal fuel for a fuel cell. Hydrogen is the energy of the future. It will be used as energy carrier as well as reactant to produce green fuels, like methane which is easier to handle. Direct coupling of a High Temperature Steam Electrolyser (HTSE) with a ...

  17. Hydrogen production from steam reforming of ethanol over Ni/MgO-CeO_2 catalyst at low temperature

    Institute of Scientific and Technical Information of China (English)

    石秋杰; 刘承伟; 谌伟庆

    2009-01-01

    MgO,CeO2 and MgO-CeO2 with different mole ratio of Mg:Ce were prepared by solid-phase burning method.Catalysts Ni/MgO,Ni/CeO2 and Ni/MgO-CeO2 were prepared by impregnation method.The catalytic properties were evaluated in ethanol steam reforming(ESR) reaction.Specific surface areas of the supports were measured by nitrogen adsorption-desorption at 77 K,and the catalysts were characterized with X-ray diffraction(XRD),temperature programmed reduction(TPR) and thermogravimetric(TG).The results showed that well...

  18. High temperature corrosion in straw-fired power plants: Influence of steam/metal temperature on corrosion rates for TP347H

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Biede, O; Larsen, OH

    2002-01-01

    The corrosion in straw-fired boilers has been investigated at various straw-fired power plants in Denmark. Water/air-cooled probes, a test superheater and test sections removed from the actual superheater have been utilised to characterise corrosion and corrosion rates. This paper describes...... the corrosion rates measured for the TP347H type steel. The corrosion morphology at high temperature consists of grain boundary attack and selective attack of chromium. The corrosion rate increases with calculated metal temperature (based on steam temperature), however there is great variation within...... these results. In individual superheaters, there are significant temperature variations i.e. higher temperature in middle banks compared to the outer banks, higher temperature in leading tubes, which have a high impact on corrosion. In a single loop the assumption that heat uptake (and heat flux) is linear...

  19. High temperature corrosion in straw-fired power plants: Influence of steam/metal temperature on corrosion rates for TP347H

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Biede, O; Larsen, OH

    2002-01-01

    The corrosion in straw-fired boilers has been investigated at various straw-fired power plants in Denmark. Water/air-cooled probes, a test superheater and test sections removed from the actual superheater have been utilised to characterise corrosion and corrosion rates. This paper describes...... the corrosion rates measured for the TP347H type steel. The corrosion morphology at high temperature consists of grain boundary attack and selective attack of chromium. The corrosion rate increases with calculated metal temperature (based on steam temperature), however there is great variation within...... these results. In individual superheaters, there are significant temperature variations i.e. higher temperature in middle banks compared to the outer banks, higher temperature in leading tubes, which have a high impact on corrosion. In a single loop the assumption that heat uptake (and heat flux) is linear...

  20. High temperature oxidation of fuel cladding candidate materials in steam-hydrogen environments

    Science.gov (United States)

    Pint, B. A.; Terrani, K. A.; Brady, M. P.; Cheng, T.; Keiser, J. R.

    2013-09-01

    Alternative fuel cladding materials to Zr alloys are being investigated for enhanced accident tolerance, which specifically involves oxidation resistance to steam or steam-H2 environments at ⩾1200 °C for short times. Based on a comparison of a range of commercial and model alloys, conventional austenitic steels do not have sufficient oxidation resistance with only ˜18Cr-10Ni. Higher alloyed type 310 stainless steel is protective but Ni is not a desirable alloy addition for this application. Results at 1350 °C indicated that FeCrAl alloys and CVD SiC remain oxidation resistant in steam. At 1200 °C, high (⩾25% Cr) ferritic alloys appear to be good candidates for this application. Higher pressures (up to 20.7 bar) and H2 additions appeared to have a limited effect on the oxidation behavior of the most oxidation resistant alloys, but higher pressures accelerated the maximum metal loss for less oxidation resistant steels and less metal loss was observed for type 317 L tubing in a H2-50%H2O environment at 10.3 bar compared to 100% H2O.

  1. A Comparison of Supercritical Carbon Dioxide Power Cycle Configurations with an Emphasis on CSP Applications (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Neises, T.; Turchi, C.

    2013-09-01

    Recent research suggests that an emerging power cycle technology using supercritical carbon dioxide (s-CO2) operated in a closed-loop Brayton cycle offers the potential of equivalent or higher cycle efficiency versus supercritical or superheated steam cycles at temperatures relevant for CSP applications. Preliminary design-point modeling suggests that s-CO2 cycle configurations can be devised that have similar overall efficiency but different temperature and/or pressure characteristics. This paper employs a more detailed heat exchanger model than previous work to compare the recompression and partial cooling cycles, two cycles with high design-point efficiencies, and illustrates the potential advantages of the latter. Integration of the cycles into CSP systems is studied, with a focus on sensible heat thermal storage and direct s-CO2 receivers. Results show the partial cooling cycle may offer a larger temperature difference across the primary heat exchanger, thereby potentially reducing heat exchanger cost and improving CSP receiver efficiency.

  2. Parameters optimization of supercritical fluid-CO2 extracts of frankincense using response surface methodology and its pharmacodynamics effects.

    Science.gov (United States)

    Zhou, Jing; Ma, Xing-miao; Qiu, Bi-Han; Chen, Jun-xia; Bian, Lin; Pan, Lin-mei

    2013-01-01

    The volatile oil parts of frankincense (Boswellia carterii Birdw.) were extracted with supercritical carbon dioxide under constant pressure (15, 20, or 25 MPa) and fixed temperature (40, 50, or 60°C), given time (60, 90, or 120 min) aiming at the acquisition of enriched fractions containing octyl acetate, compounds of pharmaceutical interest. A mathematical model was created by Box-Behnken design, a popular template for response surface methodology, for the extraction process. The response value was characterized by synthetical score, which comprised yields accounting for 20% and content of octyl acetate for 80%. The content of octyl acetate was determined by GC. The supercritical fluid extraction showed higher selectivity than conventional steam distillation. Supercritical fluid-CO(2) for extracting frankincense under optimum condition was of great validity, which was also successfully verified by the pharmacological experiments.

  3. Analysis of Low-polar Ginsenosides in Steamed Panax Ginseng at High-temperature by HPLC-ESI-MS/MS

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-chi; PI Zi-feng; LIU Chun-ming; SONG Feng-rui; LIU Zhi-qiang; LIU Shu-ying

    2012-01-01

    A high performance liquid chromatography coupled with electrospray ionization-tandem mass spectrometry(HPLC-ESI-MS/MS) method was developed for the analysis and identification of ginsenosides in the extracts of raw Panax ginseng(RPG) and steamed Panax ginseng at high temperatures(SPGHT).A total of 25 ginsenosides were extracted include of which 10 low-polar ginsenosides,such as ginsenosides F4,Rk3,Rh4,20S-Rg3,20R-Rg3 and so on,were identified according to their HPLC retention time and MS/MS data.The results indicated that the low polar ginsenosides were seldom found in RPG.For the exploration of the transformation pattern of the ginsenosides in steam processing,the standards of ginsenosides Re,Rgl,Rbl,Rc,Rb2,Rb3 and Rd were selected and hydrolyzed at a temperature of 120 ℃.The results show that these polar ginsenosides can be converted to low-polar ginsenosides such as Rg2,Rg6,F4,Rk3 and Rg5 by hydrolyzing the sugar chains.

  4. Sol–gel synthesis of highly TiO2 aerogel photocatalyst via high temperature supercritical drying

    Directory of Open Access Journals (Sweden)

    Rebah Moussaoui

    2017-09-01

    Full Text Available Nanocrystalline powders of TiO2 xerogel and aerogel were prepared by using acid-modified sol–gel approach. For TiO2 aerogel material (TA, the solvent was high temperature supercritically extracted at 300 °C and 100 bars. However, the TiO2 xerogel material (TX was dried at 200 °C and ambient pressure. The effects of the drying processes on the crystalline structure, phase transformation and grain growth were determined by Raman spectroscopy, SAED and X-ray diffraction (XRD analyses using Rietveld refinement method. The TiO2 aerogel was composed of anatase crystalline structure. The TiO2 xerogel material was composed of anatase, brookite and small amount of amorphous phase with anatase as dominant phase. The TX sample still contains a relatively high concentration of carbon than that of TA, indicating the amorphous character of TiO2 xerogel. These materials were applied as catalyst for the degradation of indigo carmine in aqueous medium. Photo-degradation ability of TA and TX was compared to the TiO2 commercial Degussa P25. The photo-catalytic results showed that the degradation efficiency was in the order TA > P25 > TX. The photo-degradation of indigo carmine followed pseudo first order reaction kinetics.

  5. Unlocking the potential of supported liquid phase catalysts with supercritical fluids: low temperature continuous flow catalysis with integrated product separation.

    Science.gov (United States)

    Franciò, Giancarlo; Hintermair, Ulrich; Leitner, Walter

    2015-12-28

    Solution-phase catalysis using molecular transition metal complexes is an extremely powerful tool for chemical synthesis and a key technology for sustainable manufacturing. However, as the reaction complexity and thermal sensitivity of the catalytic system increase, engineering challenges associated with product separation and catalyst recovery can override the value of the product. This persistent downstream issue often renders industrial exploitation of homogeneous catalysis uneconomical despite impressive batch performance of the catalyst. In this regard, continuous-flow systems that allow steady-state homogeneous turnover in a stationary liquid phase while at the same time effecting integrated product separation at mild process temperatures represent a particularly attractive scenario. While continuous-flow processing is a standard procedure for large volume manufacturing, capitalizing on its potential in the realm of the molecular complexity of organic synthesis is still an emerging area that requires innovative solutions. Here we highlight some recent developments which have succeeded in realizing such systems by the combination of near- and supercritical fluids with homogeneous catalysts in supported liquid phases. The cases discussed exemplify how all three levels of continuous-flow homogeneous catalysis (catalyst system, separation strategy, process scheme) must be matched to locate viable process conditions.

  6. Reaction of water-saturated supercritical CO2 with forsterite: Evidence for magnesite formation at low temperatures

    Science.gov (United States)

    Felmy, Andrew R.; Qafoku, Odeta; Arey, Bruce W.; Hu, Jian Zhi; Hu, Mary; Todd Schaef, H.; Ilton, Eugene S.; Hess, Nancy J.; Pearce, Carolyn I.; Feng, Ju; Rosso, Kevin M.

    2012-08-01

    The nature of the reaction products that form on the surfaces of nanometer-sized forsterite particles during reaction with H2O-saturated supercritical CO2 (scCO2) at 35 °C and 50 °C were examined under in situ conditions and ex situ following reaction. The in situ analysis was conducted by X-ray diffraction (XRD). Ex situ analysis consisted of scanning electron microscopy (SEM) examination of the surface phases and chemical characterization of precipitates using a combination of confocal Raman spectroscopy, 13C and 29Si NMR spectroscopy, and energy-dispersive X-ray spectroscopy (EDS). The results show that the forsterite surface is highly reactive with the primary reaction products being a mixture of nesquehonite (MgCO3·3H2O) and magnesite (MgCO3) at short reaction times (˜3-4 days) and then magnesite (MgCO3) and a highly porous amorphous silica phase at longer reaction times (14 days). After 14 days of reaction most of the original forsterite transformed to reaction products. Importantly, the formation of magnesite was observed at temperatures much lower (35 °C) than previously thought needed to overcome its well-known sluggish precipitation kinetics. The conversion of nesquehonite to magnesite liberates H2O which can potentially facilitate further metal carbonation, as postulated by previous investigators, based upon studies at higher temperature (80 °C). The observation that magnesite can form at lower temperatures implies that water recycling may also be important in determining the rate and extent of mineral carbonation in a wide range of potential CO2 storage reservoirs.

  7. Reaction of Water-Saturated Supercritical CO2 with Forsterite: Evidence for Magnesite Formation at Low Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Felmy, Andrew R.; Qafoku, Odeta; Arey, Bruce W.; Hu, Jian Z.; Hu, Mary Y.; Schaef, Herbert T.; Ilton, Eugene S.; Hess, Nancy J.; Pearce, Carolyn I.; Feng, Ju; Rosso, Kevin M.

    2012-08-01

    The nature of the reaction products that form on the surfaces of nanometer-sized forsterite particles during reaction with H2O saturated supercritical CO2 (scCO2) at 35 C and 50 C were examined under in situ conditions and ex situ following reaction. The in situ analysis was conducted by X-ray diffraction (XRD). Ex situ analysis consisted of scanning electron microscopy (SEM) examination of the surface phases and chemical characterization of precipitates using a combination of confocal Raman spectroscopy, 13C and 29Si NMR spectroscopy, and energy-dispersive X-ray Spectroscopy (EDS). The results show that the forsterite surface is highly reactive with the primary reaction products being a mixture of nesquehonite (MgCO3.3H2O) and magnesite (MgCO3) at short reaction times ({approx}3-4 days) and then magnesite (MgCO3) and a highly porous amorphous silica phase at longer reaction times (14 days). After 14 days of reaction most of the original forsterite transformed to reaction products. Importantly, the formation of magnesite was observed at temperatures much lower (35 C) than previously thought needed to overcome its well known sluggish precipitation kinetics. The conversion of nesquehonite to magnesite liberates H2O which can potentially facilitate further metal carbonation, as postulated by previous investigators, based upon studies at higher temperature (80 C). The observation that magnesite can form at lower temperatures implies that water recycling may also be important in determining the rate and extent of mineral carbonation in a wide range of potential CO2 storage reservoirs.

  8. Drug delivery goes supercritical

    Directory of Open Access Journals (Sweden)

    Patrick J. Ginty

    2005-08-01

    Full Text Available In the field of drug delivery, the ability to control the size, morphology, and release of drug particles is fundamental to good targeting, but is often hampered by harsh processing conditions or inadequate methods; likewise for the processing of polymeric controlled-release systems. However, the use of supercritical fluids such as supercritical CO2 (scCO2 has provided a ‘clean’ and effective alternative to traditional methods of drug and polymer processing. In particular, scCO2 has a number of unique properties that make it possible to process both bioactive molecules and amorphous polymers without using toxic organic solvents or elevated temperatures. Here, we review the positive impact that supercritical fluids have had on the micronization, encapsulation, and impregnation of molecules of interest to both the pharmaceutical and biotechnology industries.

  9. High Temperature and Pressure Steam-H2 Interaction with Candidate Advanced LWR Fuel Claddings

    Energy Technology Data Exchange (ETDEWEB)

    Pint, Bruce A [ORNL

    2012-08-01

    This report summarizes the work completed to evaluate cladding materials that could serve as improvements to Zircaloy in terms of accident tolerance. This testing involved oxidation resistance to steam or H{sub 2}-50% steam environments at 800-1350 C at 1-20 bar for short times. A selection of conventional alloys, SiC-based ceramics and model alloys were used to explore a wide range of materials options and provide guidance for future materials development work. Typically, the SiC-based ceramic materials, alumina-forming alloys and Fe-Cr alloys with {ge}25% Cr showed the best potential for oxidation resistance at {ge}1200 C. At 1350 C, FeCrAl alloys and SiC remained oxidation resistant in steam. Conventional austenitic steels do not have sufficient oxidation resistance with only {approx}18Cr-10Ni. Higher alloyed type 310 stainless steel is protective but Ni is not a desirable alloy addition for this application and high Cr contents raise concern about {alpha}{prime} formation. Higher pressures (up to 20.7 bar) and H{sub 2} additions appeared to have a limited effect on the oxidation behavior of the most oxidation resistant alloys but higher pressures accelerated the maximum metal loss for less oxidation resistant steels and less metal loss was observed in a H{sub 2}-50%H{sub 2}O environment at 10.3 bar. As some of the results regarding low-alloyed FeCrAl and Fe-Cr alloys were unexpected, further work is needed to fundamentally understand the minimum Cr and Al alloy contents needed for protective behavior in these environments in order to assist in alloy selection and guide alloy development.

  10. DESIGN OF COMBINED CYCLE GENERATION SYSTEM WITH HIGH TEMPERATURE FUEL CELL AND STEAM TURBINE

    Institute of Scientific and Technical Information of China (English)

    Yu Lijun; Yuan Junqi; Cao Guangyi

    2003-01-01

    For environment protection and high efficiency, development of new concept power plant has been required in China. The fuel cell is expected to be used in a power plant as a centralized power station or distributed power plant. It is a chemical power generation device that converts the energy of a chemical reaction directly into electrical energy and not limited by Carnot cycle efficiency. The molten carbonate fuel cell (MCFC) power plant has several attractive features I.e. High efficiency and lower emission of Nox and Sox. A combined cycle generation system with MCFC and steam turbine is designed. Its net electrical efficiency LHV is about 55%.

  11. A Numerical Study on Mass Transfer and Methanol Conversion Efficiency According to Porosity and Temperature Change of Curved Channel Methanol-Steam Reformer

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Hong Seok; Lee, Chung Ho; Suh, Jeong Se [Gyeongsang Nat’l Univ., Jinju (Korea, Republic of)

    2016-11-15

    Micro methanol-steam reformer for fuel cell can effectively produce hydrogen as reforming response to steam takes place in low temperature (less than 250℃). This study conducted numerical research on this reformer. First, study set wall temperature of the reformer at 100, 140, 180 and 220℃ while methanol conversion efficiency was set in 0, 0.072, 3.83 and 46.51% respectively. Then, porosity of catalyst was set in 0.1, 0.35, 0.6 and 0.85 and although there was no significant difference in methanol conversion efficiency, values of pressure drop were 4645.97, 59.50, 5.12 and 0.45 kPa respectively. This study verified that methanol-steam reformer rarely responds under the temperature of 180℃ and porosity does not have much effect on methanol conversion efficiency if the fluid flowing through reformer lowers activation energy by sufficiently contacting reformer.

  12. Effects of Steaming, Drying Temperature, and Adhesive Type on Static Bending Properties of LVL made of Picea orientalis and Abies nordmanniana veneers

    Directory of Open Access Journals (Sweden)

    Huseyin Peker

    2014-11-01

    Full Text Available The modulus of elasticity (MOE and modulus of rupture (MOR were evaluated for laminated veneer lumber (LVL in static bending. The studied species were spruce (Picea orientalis and fir (Abies nordmanniana originated from the Eastern Black sea region and prepared with phenol-formaldehyde and melamine-urea-formaldehyde. The effect of wood species, steaming, drying temperature, and type of adhesive on static bending MOE and MOR were determined. According to the experimental results, the bending strength of spruce wood (Maçka treated with phenol formadehyde adhesives is the highest for the specimens steamed for 6 h at a drying temperature of 110 ºC. Furthermore, the modulus of elasticity for spruce wood (Maçka treated with phenol formadehyde adhesive is the highest for the specimens steamed for 12 h and subjected to a drying temperature of 150 ºC.

  13. Assessment of MTI Water Temperature Retrievals with Ground Truth from the Comanche Peak Steam Electric Station Cooling Lake

    Energy Technology Data Exchange (ETDEWEB)

    Kurzeja, R.J.

    2002-12-09

    Surface water temperatures calculated from Multispectral Thermal Imager (MTI) brightness temperatures and the robust retrieval algorithm, developed by the Los Alamos National Laboratory (LANL), are compared with ground truth measurements at the Squaw Creek reservoir at the Comanche Peak Steam Electric Station near Granbury Texas. Temperatures calculated for thirty-four images covering the period May 2000 to March 2002 are compared with water temperatures measured at 10 instrumented buoy locations supplied by the Savannah River Technology Center. The data set was used to examine the effect of image quality on temperature retrieval as well as to document any bias between the sensor chip arrays (SCA's). A portion of the data set was used to evaluate the influence of proximity to shoreline on the water temperature retrievals. This study found errors in daytime water temperature retrievals of 1.8 C for SCA 2 and 4.0 C for SCA 1. The errors in nighttime water temperature retrievals were 3.8 C for SCA 1. Water temperature retrievals for nighttime appear to be related to image quality with the largest positive bias for the highest quality images and the largest negative bias for the lowest quality images. The daytime data show no apparent relationship between water temperature retrieval error and image quality. The average temperature retrieval error near open water buoys was less than corresponding values for the near-shore buoys. After subtraction of the estimated error in the ground truth data, the water temperature retrieval error was 1.2 C for the open-water buoys compared to 1.8 C for the near-shore buoys. The open-water error is comparable to that found at Nauru.

  14. Design and Simulation of Predictive Controller for Boiler Main Steam Temperature Control Systems%锅炉主蒸汽温度控制系统预测控制设计与仿真

    Institute of Scientific and Technical Information of China (English)

    杜文嫚; 韩璞

    2013-01-01

    This paper studied the control problems of the boiler main steam temperature control system.For the characteristics of large delay and big time inertia of 600 MW extra supercritical units,IMC and IMC-PID controllers were established.For the same controlled object,Matlab/simulink was used to obtain the results of every controller.And with different filter time,constant accommodation time and system robustness were analysed.The advantages and disadvantages of each controller were obtained according to the comparison between IMC controller,IMC-PID controller and traditional PID controller.%研究锅炉主蒸汽温度系统的控制问题,针对某600MW超临界机组主蒸汽温度控制系统大迟延、大时间惯性的特点,建立了内模控制器和IMC-PID控制器.针对相同的被控对象,用matlab的simulink搭建仿真回路,对不同控制器的控制效果进行了仿真,分析了不同滤波器时间常数下的调节时间和系统鲁棒性.最后将IMC控制、IMC-PID控制和传统PID控制的仿真结果进行了比较,总结了各自的优点和缺点.

  15. Efficient use of low-temperature and low-pressure steam for heating different media by dynamic steam blending; Effiziente Dampfverwertung von niedrig Temperatur und Niederdruck-Dampf zur Aufheizung verschiedenster Medien mittels dynamischer Dampfeinmischung

    Energy Technology Data Exchange (ETDEWEB)

    Michal, L. [Andritz AG, Graz (Austria); Wallner, C.

    2007-07-01

    In this novel steam blending system, steam is added to the medium to be heated at a high relative speed. The dynamic mixing process provides even and fine distribution of the steam through the medium. The contact surfaces of the various phases of the gaseous steam and the liquid medium are enlarged substantially. This results in rapid and careful heat transfer from the steam to the medium, because the steam condenses immediately, minimizing steam bubbles. The key component consists mainly of a mixer casing and a rotating steam manifold. The steam needed to heat the stock is fed to the manifold through the specially shaped casing. The manifold, which is mounted on the extended motor shaft, rotates at the motor speed. The rotating steam nozzles cover the entire cross-section and 'plough' through the linear medium flow in radial direction. The large contact surfaces between the steam and the medium, as well as preventing local overheating of the medium, obviate condensation surges to a large extent. (orig.)

  16. Complete Fiber/Copper Cable Solution for Long-Term Temperature and Pressure Measurement in Supercritical Reservoirs and EGS Wells

    Energy Technology Data Exchange (ETDEWEB)

    Pastouret, Alan [Draka Cableteq USA, Inc., North Dighton, MA (United States); Gooijer, Frans [Draka Cableteq USA, Inc., North Dighton, MA (United States); Overton, Bob [Draka Cableteq USA, Inc., North Dighton, MA (United States); Jonker, Jan [Draka Cableteq USA, Inc., North Dighton, MA (United States); Curley, Jim [Draka Cableteq USA, Inc., North Dighton, MA (United States); Constantine, Walter [Draka Cableteq USA, Inc., North Dighton, MA (United States); Waterman, Kendall Miller [Draka Cableteq USA, Inc., North Dighton, MA (United States)

    2015-11-13

    High Temperature insulated wire and optical fiber cable is a key enabling technology for the Geothermal Technologies Program (GTP). Without insulated electrical wires and optical fiber, downhole temperature and pressure sensors, flow meters and gauges cannot communicate with the surface. Unfortunately, there are currently no insulated electrical wire or fiber cable constructions capable of surviving for extended periods of deployment in a geothermal well (240-325°C) or supercritical (374°C) reservoir. This has severely hindered engineered reservoir creation, management and utilization, as hot zones and cool water intrusions cannot be understood over time. The lack of a insulated electrical wire and fiber cable solution is a fundamental limitation to the viability of this energy source. The High Temperature Downhole Tools target specification is development of tools and sensors for logging and monitoring wellbore conditions at depths of up to 10,000 meters and temperatures up to 374oC. It well recognized in the industry that no current electronic or fiber cable can be successfully deployed in a well and function successfully for more a few days at temperatures over 240oC. The goal of this project was to raise this performance level significantly. Prysmian Group’s objective in this project was to develop a complete, multi-purpose cable solution for long-term deployment in geothermal wells/reservoirs that can be used with the widest variety of sensors. In particular, the overall project objective was to produce a manufacturable cable design that can perform without serious degradation: • At temperatures up to 374°C; • At pressures up to 220 bar; • In a hydrogen-rich environment; and • For the life of the well (> 5 years). This cable incorporates: • Specialty optical fibers, with specific glass chemistry and high temperature and pressure protective coatings for data communication and distributed temperature and pressure sensing, and • High-temperature

  17. Effects of Catalysts and Membranes on the Performance of Membrane Reactors in Steam Reforming of Ethanol at Moderate Temperature

    Directory of Open Access Journals (Sweden)

    Manabu Miyamoto

    2016-06-01

    Full Text Available Steam reforming of ethanol in the membrane reactor using the Pd77Ag23 membrane was evaluated in Ni/CeO2 and Co/CeO2 at atmospheric pressure. At 673 K, the H2 yield in the Pd77Ag23 membrane reactor over Co/CeO2 was found to be higher than that over Ni/CeO2, although the H2 yield over Ni/CeO2 exceeded that over Co/CeO2 at 773 K. This difference was owing to their reaction mechanism. At 773 K, the effect of H2 removal could be understood as the equilibrium shift. In contrast, the H2 removal kinetically inhibited the reverse methane steam reforming at low temperature. Thus, the low methane-forming reaction rate of Co/CeO2 was favorable at 673 K. The addition of a trace amount of Ru increased the H2 yield effectively in the membrane reactor, indicating that a reverse H2 spill over mechanism of Ru would enhance the kinetical effect of H2 separation. Finally, the effect of membrane performance on the reactor performance by using amorphous alloy membranes with different compositions was evaluated. The H2 yield was set in the order of H2 permeation flux regardless of the membrane composition.

  18. Universal scaling behavior of supercritical matter

    CERN Document Server

    Bolmatov, Dima; Trachenko, K

    2013-01-01

    Properties of supercritical fluids have been of enduring interest since the critical phenomena were discovered by Cagniard de la Tour in 1822, stimulating fundamental theoretical work and development of experimental techniques. Here, we study the thermodynamic properties of the supercritical state, and discover that specific heat shows a crossover between two different dynamic regimes of the low-temperature rigid liquid and high-temperature non-rigid supercritical fluid. We formulate a theory of heat capacity above the crossover, and find good agreement between calculated and experimental data for rare-gas supercritical liquids (Ne, Ar, Kr and Xe) with no free fitting parameters. We derive the relationship between scaling exponents of heat capacity and viscosity in the supercritical region, and show that these exponents exhibit universality. The universality is explained by the universal temperature behavior of the maximal length of the longitudinal phonons that can exist in the supercritical system and that ...

  19. Experimental Adsorption Isotherm of Methane onto Activated Carbon at Sub- and Supercritical Temperatures

    KAUST Repository

    Rahman, Kazi Afzalur

    2010-11-11

    This paper presents the experimentally measured adsorption isotherm data for methane onto the pitch-based activated carbon type Maxsorb III for temperatures ranging from (120 to 220) K and pressures up to 1.4 MPa. These data are useful to study adsorbed natural gas (ANG) storage systems when the low temperature natural gas regasified from the liquid phase is considered to charge in the storage chamber. Adsorption parameters were evaluated from the isotherm data using the Tóth and Dubinin-Astakhov models. The isosteric heat of adsorption, which is concentration- and temperature-dependent, is extracted from the data. The Henry\\'s law coefficients for the methane/Maxsorb III pairs are evaluated at various temperatures. © 2010 American Chemical Society.

  20. Apparatus for and Method of Monitoring Condensed Water in Steam Pipes at High Temperature

    Science.gov (United States)

    Lih, Shyh-Shiuh (Inventor); Lee, Hyeong Jae (Inventor); Bar-Cohen, Yoseph (Inventor); Bao, Xiaoqi (Inventor)

    2016-01-01

    A system and method for monitoring the properties of a fluid, such as water, in a steam pipe without mechanically penetrating the wall of the pipe. The system uses a piezoelectric transducer to launch an ultrasonic probe signal into the pipe. Reflected ultrasonic signals are captured in a transducer, which can be the same transducer that launched the probe signal. The reflected signals are subjected to data processing, which can include filtering, amplification, analog-to-digital conversion and autocorrelation analysis. A result is extracted which is indicative of a property of the fluid, such as a height of the condensed fluid, a cavitation of the condensed fluid, and a surface perturbation of the condensed fluid. The result can be recorded, displayed, and/or transmitted to another location. One embodiment of the system has been constructed and tested based on a general purpose programmable computer using instructions recorded in machine-readable non-volatile memory.

  1. In-Service Monitoring of Steam Pipe Systems at High Temperatures

    Science.gov (United States)

    Bar-Cohen, Yoseph (Inventor); Lih, Shyh-Shiuh (Inventor); Badescu, Mircea (Inventor); Bao, Xiaoqi (Inventor); Sherrit, Stewart (Inventor); Scott, James Samson (Inventor); Blosiu, Julian O. (Inventor); Widholm, Scott E. (Inventor)

    2014-01-01

    A system and method for monitoring the properties of a fluid, such as water, in a steam pipe without mechanically penetrating the wall of the pipe. The system uses a piezoelectric transducer to launch an ultrasonic probe signal into the pipe. Reflected ultrasonic signals are captured in a transducer, which can be the same transducer that launched the probe signal. The reflected signals are subjected to data processing, which can include filtering, amplification, analog-to-digital conversion and autocorrelation analysis. A result is extracted which is indicative of a property of the fluid, such as a height of the condensed fluid, a cavitation of the condensed fluid, and a surface perturbation of the condensed fluid. The result can be recorded, displayed, and/or transmitted to another location. One embodiment of the system has been constructed and tested based on a general purpose programmable computer using instructions recorded in machine-readable non-volatile memory.

  2. J-resistance curves for Inconel 690 and Incoloy 800 nuclear steam generators tubes at room temperature and at 300 °C

    Science.gov (United States)

    Bergant, Marcos A.; Yawny, Alejandro A.; Perez Ipiña, Juan E.

    2017-04-01

    The structural integrity of steam generator tubes is a relevant issue concerning nuclear plant safety. In the present work, J-resistance curves of Inconel 690 and Incoloy 800 nuclear steam generator tubes with circumferential and longitudinal through wall cracks were obtained at room temperature and 300 °C using recently developed non-standard specimens' geometries. It was found that Incoloy 800 tubes exhibited higher J-resistance curves than Inconel 690 for both crack orientations. For both materials, circumferential cracks resulted into higher fracture resistance than longitudinal cracks, indicating a certain degree of texture anisotropy introduced by the tube fabrication process. From a practical point of view, temperature effects have found to be negligible in all cases. The results obtained in the present work provide a general framework for further application to structural integrity assessments of cracked tubes in a variety of nuclear steam generator designs.

  3. Research of IGPC Control Strategy Based-on Hybrid Optimization for Power Station Boiler Superheated Steam Temperature

    Directory of Open Access Journals (Sweden)

    Benxian Xiao

    2014-01-01

    Full Text Available Implicit Generalized Predictive Control (IGPC algorithm can directly identify controller parameters without the need of solving Diophantine equation, thus can reduce the on-line algorithm computation time. In order to improve IGPC performance and extend its application, modified Particle Swarm Optimization (PSO algorithm is introduced into IGPC rolling horizon optimization, combined with general IGPC gradient optimization method under unconstrained condition, a new hybrid optimization method is obtained, this modified IGPC can be used to both of the non-constraint industry process control and the constraint industry process control. Aiming at the superheated steam temperature control of sub-critical 600MW boiler, a new cascade compound control strategy that combines an outer loop IGPC master adjuster and an inner loop PID auxiliary adjuster is adopted. Finally the simulation results have shown that the proposed method can constrain the control action, prevent dramatic change of the input signal, thus can achieve good static and dynamic performances.

  4. Modeling Cyclic Fatigue Hysteresis Loops of 2D Woven Ceramic Matrix Composites at Elevated Temperatures in Steam

    Directory of Open Access Journals (Sweden)

    Longbiao Li

    2016-05-01

    Full Text Available In this paper, the cyclic fatigue hysteresis loops of 2D woven SiC/SiC ceramic matrix composites (CMCs at elevated temperatures in steam have been investigated. The interface slip between fibers and the matrix existing in matrix cracking modes 3 and 5, in which matrix cracking and interface debonding occurred in longitudinal yarns, is considered as the major reason for hysteresis loops of 2D woven CMCs. The hysteresis loops of 2D SiC/SiC composites corresponding to different peak stresses, test conditions, and loading frequencies have been predicted using the present analysis. The damage parameter, i.e., the proportion of matrix cracking mode 3 in the entire matrix cracking modes of the composite, and the hysteresis dissipated energy increase with increasing fatigue peak stress. With increasing cycle number, the interface shear stress in the longitudinal yarns decreases, leading to transition of interface slip types of matrix cracking modes 3 and 5.

  5. Analysis of two-phase flow instability in helical tube steam generator in high temperature gas cooled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yu; Lv, Xuefeng; Wang, Shengfei; Niu, Fenglei; Tian, Li [North China Electric Power Univ., Beijing (Switzerland)

    2012-03-15

    The steam generator composed of multi-helical tubes is used in high temperature gas cooled reactors and two-phase flow instability should be avoided in design. And density-wave oscillation which is mainly due to flow, density and the relationship between the pressure drop delays and feedback effects is one of the two-phase flow instability phenomena easily to occur. Here drift-flux model is used to simulate the performance of the fluid in the secondary side and frequency domain and time domain methods are used to evaluate whether the density-wave oscillation will happen or not. Several operating conditions with nominal power from 15% to 30% are calculated in this paper. The results of the two methods are in accordance, flow instability will occur when power is less than 20% nominal power, which is also according with the result of the experiments well.

  6. Discussion on Feasibility and Economy of 1000-MW Ultra-Supercritical Air-Cooling Unit

    Institute of Scientific and Technical Information of China (English)

    Zhu Jun; Wang Yunze; Jin Wen

    2007-01-01

    @@ Based on analysis on types and features of domestically made 1000-MW large ultra supercritical steam turbine and 600-MW air cooling steam turbine,the author puts forward that 1000-MW ultra supercritical air-cooling turbine can be assembled with high and medium pressure cylinder modules of 1000-MW ultra-supercritical steam turbine and low-pressure cylinder module of 600-MW tow-cylinder and tow-exhaust air-cooling turbine.In addition,the economy of the assembled turbine is discussed, and designing considerations and issues need to be furtherstudied are proposed as well.

  7. Investigation on steam oxidation behaviour of TP347H FG Part I Exposure at 256 bar

    DEFF Research Database (Denmark)

    Jianmin, J; Montgomery, Melanie; Larsen, OH

    2005-01-01

    The stainless steel TP347H FG is a candidate material for the final stage tubing of superheater and reheater sections of ultra supercritical boilers operated at steam temperatures up to 620C in the mild corrosion environments of coal-firing. A series of field tests has been conducted with the afo......The stainless steel TP347H FG is a candidate material for the final stage tubing of superheater and reheater sections of ultra supercritical boilers operated at steam temperatures up to 620C in the mild corrosion environments of coal-firing. A series of field tests has been conducted...... with the aforementioned steel in coal-fired boilers and this paper focuses on the steam oxidation behaviour for specimens tested at various metal temperatures for exposure times of 7700, 23000 and 30000 hours as investigated by light optical and scanning electron microscopy. The oxide present on the specimens is a duplex......, where the larger the metal grain size, the thicker the oxidation scale. This gave the appearance of uneven inner oxides with a varying pit thickness. Comparison of the pit thickness measurement and oxide composition reveals that the oxidation rate is fast during the initial oxidation stage...

  8. A process for generating power from the oxidation of coal in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    M.D. Bermejo; M.J. Cocero; F. Fernandez-Polanco [Universidad de Valladolid, Valladolid (Spain). Departamento de Ingenieria Quimica

    2004-01-01

    A theoretical study of power generation from oxidation of coal by supercritical water oxidation (SCWO) is presented. Two versions of SCWO power plant are compared to two of the most efficient conventional power plant processes: pulverised coal power plants and pressurised fluidised bed power plant. The effects of steam pressure and temperature on produced (W{sub p}), consumed (W{sub c}) and net work (W{sub N}) are calculated in order to compare the efficiency of these power plants for the same steam conditions. Enthalpies have been calculated using residual enthalpies by Peng Robinson equation of state. Calculated results show that net work in SCWO power plant is 5% higher than in other power plants, due to the fact that no air surplus is necessary for complete combustion and because steam is produced by direct heating. Energetic efficiency of SCWO increases more quickly with temperature than for the other power plants. The effect of steam pressure is different: until 30 MPa power plant efficiencies increase more quickly in SCWO power plants than in conventional plants, but when steam pressures increases beyond 30 MPa, efficiencies decrease in SCWO power plants. 21 refs., 12 figs., 7 tabs.

  9. Technique of optimization of minimum temperature driving forces in the heaters of regeneration system of a steam turbine unit

    Science.gov (United States)

    Shamarokov, A. S.; Zorin, V. M.; Dai, Fam Kuang

    2016-03-01

    At the current stage of development of nuclear power engineering, high demands on nuclear power plants (NPP), including on their economy, are made. In these conditions, improving the quality of NPP means, in particular, the need to reasonably choose the values of numerous managed parameters of technological (heat) scheme. Furthermore, the chosen values should correspond to the economic conditions of NPP operation, which are postponed usually a considerable time interval from the point of time of parameters' choice. The article presents the technique of optimization of controlled parameters of the heat circuit of a steam turbine plant for the future. Its particularity is to obtain the results depending on a complex parameter combining the external economic and operating parameters that are relatively stable under the changing economic environment. The article presents the results of optimization according to this technique of the minimum temperature driving forces in the surface heaters of the heat regeneration system of the steam turbine plant of a K-1200-6.8/50 type. For optimization, the collector-screen heaters of high and low pressure developed at the OAO All-Russia Research and Design Institute of Nuclear Power Machine Building, which, in the authors' opinion, have the certain advantages over other types of heaters, were chosen. The optimality criterion in the task was the change in annual reduced costs for NPP compared to the version accepted as the baseline one. The influence on the decision of the task of independent variables that are not included in the complex parameter was analyzed. An optimization task was decided using the alternating-variable descent method. The obtained values of minimum temperature driving forces can guide the design of new nuclear plants with a heat circuit, similar to that accepted in the considered task.

  10. Optimization of High Temperature and Pressurized Steam Modified Wood Fibers for High-Density Polyethylene Matrix Composites Using the Orthogonal Design Method

    Directory of Open Access Journals (Sweden)

    Xun Gao

    2016-10-01

    Full Text Available The orthogonal design method was used to determine the optimum conditions for modifying poplar fibers through a high temperature and pressurized steam treatment for the subsequent preparation of wood fiber/high-density polyethylene (HDPE composites. The extreme difference, variance, and significance analyses were performed to reveal the effect of the modification parameters on the mechanical properties of the prepared composites, and they yielded consistent results. The main findings indicated that the modification temperature most strongly affected the mechanical properties of the prepared composites, followed by the steam pressure. A temperature of 170 °C, a steam pressure of 0.8 MPa, and a processing time of 20 min were determined as the optimum parameters for fiber modification. Compared to the composites prepared from untreated fibers, the tensile, flexural, and impact strength of the composites prepared from modified fibers increased by 20.17%, 18.5%, and 19.3%, respectively. The effect on the properties of the composites was also investigated by scanning electron microscopy and dynamic mechanical analysis. When the temperature, steam pressure, and processing time reached the highest values, the composites exhibited the best mechanical properties, which were also well in agreement with the results of the extreme difference, variance, and significance analyses. Moreover, the crystallinity and thermal stability of the fibers and the storage modulus of the prepared composites improved; however, the hollocellulose content and the pH of the wood fibers decreased.

  11. Modification of technological control units for superheated steam temperature at 210-MW power units of the Primor'ye Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    V.V. Slesarenko; A.A. Belousov; V.V. Milush [Far East State Engineering University, Vladivostok (Russian Federation)

    2008-06-15

    The results of analysis of operation of the temperature control system for superheated steam at the BKZ-670-140F boilers of the Primor'ye Power Plant (GRES) are presented. The possibility of updating of the injection system to improve the reliability and economic efficiency of power units of electric power plants is considered.

  12. Modification of technological control units for superheated steam temperature at 210-MW power units of the Primor'ye Power Plant

    Science.gov (United States)

    Slesarenko, V. V.; Belousov, A. A.; Milush, V. V.

    2008-06-01

    The results of analysis of operation of the temperature control system for superheated steam at the BKZ-670-140F boilers of the Primor’ye Power Plant (GRES) are presented. The possibility of updating of the injection system to improve the reliability and economic efficiency of power units of electric power plants is considered.

  13. High-temperature steam oxidation testing of select advanced replacement alloys for potential core internals

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Lizhen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pint, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-05-19

    Coupons from a total of fourteen commercial and custom fabricated alloys were exposed to 1 bar full steam with ~10 ppb oxygen content at 600 and 650°C. The coupons were weighed at 500-h intervals with a total exposure time of 5,000 h. The fourteen alloys are candidate alloys selected under the ARRM program, which include three ferritic steels (Grade 92, 439, and 14YWT), three austenitic stainless steels (316L, 310, and 800), seven Ni-base superalloys (X750, 725, C22, 690, 625, 625 direct-aging, and 625- plus), and one Zr-alloy (Zr–2.5Nb). Among the alloys, 316L and X750 are served as reference alloys for low- and high-strength alloys, respectively. The candidate Ni-base superalloy 718 was procured too late to be included in the tests. The corrosion rates of the candidate alloys can be approximately interpreted by their Cr, Ni and Fe content. The corrosion rate was significantly reduced with increasing Cr content and when Ni content is above ~15 wt%, but not much further reduced when Fe content is less than ~55 wt%. Simplified thermodynamics analyses of the alloy oxidation provided reasonable indications for the constituents of oxide scales formed on the alloys and explanations for the porosity and exfoliation phenomena because of the nature of specific types of oxides.

  14. Investigation of radiation equilibrium in nitrogen tetroxide at supercritical temperatures and pressures

    Energy Technology Data Exchange (ETDEWEB)

    Gol' tsev, A.A.; Doroshkevich, V.N.; Nesterenko, V.B.; Nichipor, G.V.; Ukraintseva, L.V.

    1982-01-01

    The amounts of nitrogen and nitrous oxide as a result of nitrogen tetroxide ..gamma..-radiolysis have been measured at the temperature of 473 K, pressure of 15.7 MPa, dose rate of 5Wt/kg, D = 9.6x10/sup 7/ j/kg, times to 5350 hours to maximum degree of conversion of 15%. The amounts of nitrogen and nitrous oxide from nitrogen tetroxide n, ..gamma..-radiolysis have been measured at 523 K, 11.7 MPa, dose of 2.4x10/sup 8/ j/kg to the degree of conversion of 39%. Kinetic analysis of the experimental data with reference to the known reactions evidence that the calculated and experimental concentrations agree satisfactorily at small degrees of conversion.

  15. Feasibility Study of Supercritical Light Water Cooled Reactors for Electric Power Production, Progress Report for Work Through September 2003, 2nd Annual/8th Quarterly Report

    Energy Technology Data Exchange (ETDEWEB)

    Philip E. MacDonald

    2003-09-01

    The supercritical water-cooled reactor (SCWR) is one of the six reactor technologies selected for research and development under the Generation-IV program. SCWRs are promising advanced nuclear systems because of their high thermal efficiency (i.e., about 45% vs. about 33% efficiency for current Light Water Reactors, LWRs) and considerable plant simplification. SCWRs are basically LWRs operating at higher pressure and temperatures with a direct once-through cycle. Operation above the critical pressure eliminates coolant boiling, so the coolant remains single-phase throughout the system. Thus the need for recirculation and jet pumps, a pressurizer, steam generators, steam separators and dryers is eliminated. The main mission of the SCWR is generation of low-cost electricity. It is built upon two proven technologies, LWRs, which are the most commonly deployed power generating reactors in the world, and supercritical fossil-fired boilers, a large number of which is also in use around the world.

  16. 高温蒸汽松木颗粒富氢气化试验%High-temperature steam gasification of pine particles for hydrogen-rich gas

    Institute of Scientific and Technical Information of China (English)

    牛永红; 韩枫涛; 陈义胜

    2016-01-01

    The objective of the research was to use pine particles as raw material with self-made downdraft gasifier system platform for gasification test. The test was carried out under different conditions of steam flow rate and gasification temperature. Analysis of biomass gasification reaction mechanism was done by using equilibrium theory and chemical reaction kinetics of chemical reaction. Our results showed that method of granulation of biomass wastes can effectively improve stacking density of biomass. By using this method, pine wastes stacking density can be as high as 520 kg/m3. Also, by using pine particles for gasification, the bridging phenomenon of material accumulation in the furnace was decreased, thus making the test in a continuous and stable condition, and improving the biomass gasification effect. With the increase of gasification temperature, the degree of gasification reactions was increased as well as the steam reforming which helped the participation of hydrocarbon and coke As such hydrogen content increased, and the volume fraction of H2 increased from 23.38% at 700℃ to 44.79% at 950℃ which nearly doubled that in 700℃ Moreover, the volume fraction of CnHm decreased with the gasification temperature increase. However, due to the conversion of carbon monoxide and steam after 900℃, the volume fractions for H2, CO, and CO2decreased with the increase of temperature. Besides, high-temperature steam had higher specific enthalpy, which might promote the reforming reaction of steam towards the generation of H2 The high temperature steam is also a gasification agent and heat carrier in the gasification process. It provides partial energy of biomass gasification reactions. Steam flow is another important indicator of high temperature steam gasification technology. In the range of temperature of 850-950℃, the increase of steam flow increased the steam reforming which was in the participation of hydrocarbon and coke. With steam flow increased from 0.3 to

  17. 超临界CO2萃取法与水蒸气蒸馏法提取香茅草挥发油化学成分比较%Comparison of Chemical Components in the Essential Oil Extracted by Supercritical CO2 Fluid and Steam Distillation from Cymbopogon citratus

    Institute of Scientific and Technical Information of China (English)

    谢丽莎; 龚志强; 欧阳炜; 黄振园

    2012-01-01

    [Objective] To compare the chemical components in the essential oil extracled by different methods from Cymbopogon citratus (DC. ) Stapf. [ Method] The essential oils were extracted by supercritical CO3 fluid and steam distillation. And then their chemical components were qualitatively and quantitatively analyzed by GC-MS. [Result] 31 components were identified in the essential oil extracted by supercritical CO, fluid from Cymbopogon citratus, accounting for over 91% of the total volatile components; while 17 components were identified in the essential oil extracted by steam distillation, accounting for about 94% of the total components. The essential oil extracted by the two methods had different types and different contents of chemical components, geranial and neral were the most. [ Conclusion ] The essential oil extracted by supercritical C02 fluid is better than that extracted by steam distillation to truly and comprehensively reflect the chemical components in medicines.%[目的]比较不同方法提取的香茅草挥发油化学成分.[方法]采用超临界CO2流体萃取法(SCDE)及水蒸气蒸馏法(SD)从香茅草中提取挥发油,用气相色谱-质谱联用技术(GC-MS)对其化学成分进行定性定量分析.[结果]在超临界CO2流体萃取法提取的挥发油中共鉴定了31种成分,占挥发油总成分的91%以上;在水蒸气蒸馏法提取的挥发油中共鉴定了17种成分,占挥发油的94%以上.2种提取方法得到的挥发油组分及其含量差异较大,含量最高的都是香叶醛和橙花醛.[结论]超临界CO2流体萃取法提取的挥发油比水蒸气蒸馏法能更真实、全面的反映药材中的化学成分.

  18. High temperature oxidation behavior of austenitic stainless steel AISI 304 in steam of nanofluids contain nanoparticle ZrO2

    Energy Technology Data Exchange (ETDEWEB)

    Prajitno, Djoko Hadi, E-mail: djokohp@batan.go.id; Syarif, Dani Gustaman, E-mail: djokohp@batan.go.id [Research Center for Nuclear Materials and Radiometry, Jl. Tamansari 71, Bandung 40132 (Indonesia)

    2014-03-24

    The objective of this study is to evaluate high temperature oxidation behavior of austenitic stainless steel SS 304 in steam of nanofluids contain nanoparticle ZrO{sub 2}. The oxidation was performed at high temperatures ranging from 600 to 800°C. The oxidation time was 60 minutes. After oxidation the surface of the samples was analyzed by different methods including, optical microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD). X-ray diffraction examination show that the oxide scale formed during oxidation of stainless steel AISI 304 alloys is dominated by iron oxide, Fe{sub 2}O{sub 3}. Minor element such as Cr{sub 2}O{sub 3} is also appeared in the diffraction pattern. Characterization by optical microscope showed that cross section microstructure of stainless steel changed after oxidized with the oxide scale on the surface stainless steels. SEM and x-ray diffraction examination show that the oxide of ZrO{sub 2} appeared on the surface of stainless steel. Kinetic rate of oxidation of austenite stainless steel AISI 304 showed that increasing oxidation temperature and time will increase oxidation rate.

  19. Heat and fuel coupled operation of a high temperature polymer electrolyte fuel cell with a heat exchanger methanol steam reformer

    Science.gov (United States)

    Schuller, G.; Vázquez, F. Vidal; Waiblinger, W.; Auvinen, S.; Ribeirinha, P.

    2017-04-01

    In this work a methanol steam reforming (MSR) reactor has been operated thermally coupled to a high temperature polymer electrolyte fuel cell stack (HT-PEMFC) utilizing its waste heat. The operating temperature of the coupled system was 180 °C which is significantly lower than the conventional operating temperature of the MSR process which is around 250 °C. A newly designed heat exchanger reformer has been developed by VTT (Technical Research Center of Finland LTD) and was equipped with commercially available CuO/ZnO/Al2O3 (BASF RP-60) catalyst. The liquid cooled, 165 cm2, 12-cell stack used for the measurements was supplied by Serenergy A/S. The off-heat from the electrochemical fuel cell reaction was transferred to the reforming reactor using triethylene glycol (TEG) as heat transfer fluid. The system was operated up to 0.4 A cm-2 generating an electrical power output of 427 Wel. A total stack waste heat utilization of 86.4% was achieved. It has been shown that it is possible to transfer sufficient heat from the fuel cell stack to the liquid circuit in order to provide the needed amount for vaporizing and reforming of the methanol-water-mixture. Furthermore a set of recommendations is given for future system design considerations.

  20. Optimization of supercritical fluid extraction of essential oils and fatty acids from flixweed (Descurainia Sophia L.) seed using response surface methodology and central composite design.

    Science.gov (United States)

    Ara, Katayoun Mahdavi; Jowkarderis, Mina; Raofie, Farhad

    2015-07-01

    Essential oils and fatty acids of Descurainia sophia L. seed were obtained by supercritical CO2 extraction and steam distillation methods. The effect of different parameters such as pressure, temperature, modifier volume, dynamic and static extraction timeon the extraction yield were optimized using a central composite design after a 2 (n-1) fractional factorial design. The results showed that under the pressure of 355 bar, temperature of 65 °C, methanol volume of 150 μL, dynamic and static extraction times of 35 and 10 min, respectively, the major components were methyl linoleate (18.2 %), camphor (12.32 %), cis-thujone (11.3 %) and trans-caryophyllene (9.17 %). The results indicated that by using the proper conditions, the supercritical fluid extraction is more selective than the steam distillation method. Extraction yields based on supercritical fluid extraction varied in the range of 0.68 to 17.1 % (w/w), and the extraction yield based on the steam distillation was 0.25 % (v/w).

  1. Components Comparison of Essential Oil Extracted from Schisandrae Sphenantherae Fructus by Supercritical Fluid CO2 Extraction and Steam Distillation%超临界流体CO2提取法与水蒸汽蒸馏法提取南五味子挥发油的成分比较

    Institute of Scientific and Technical Information of China (English)

    毛日文; 张敏; 徐佐旗; 赵婷; 樊懿娜; 周叶; 仰榴青

    2011-01-01

    Objective To compare the different chemical constituents of essential oil from Schisandrae Sphenantherae Fractus extracted by supercritical fluid C02 extraction (SFE-C02) and steam distillation (SD).Methods The orthogonal test was carried out to determine the optimal extraction conditions according to the yield of essential oil extracted by SFE-C02.The SFE-C02 and SD were used to extract essential oil which was identified by GC-MS.Results The optimal SFE-C02 extraction conditions were as follows: The extraction temperature was 40 ℃, with extraction pressure 15 Mpa and extraction time 3 hours.The average extraction rate of the essential oil by SFE-C02 and SD were 8.2 7% and 1.4 %, and 16 and 24 components were identified by GC-MS analysis, respectively.Conclusion The results indicated that the average extraction rate of essential oil by SFE-C02 was higher than that by SD, and both the components and content of the oil were different.%目的:比较超临界流体CO2提取法和水蒸汽蒸馏法提取南五味子挥发油的主要化学成分.方法:通过正交试验确定超临界流体CO2提取的最佳工艺条件,采用超临界流体CO2提取和水蒸汽蒸馏法提取五味子挥发油,并采用GC-MS方法分析成分.结果:超临界流体CO2提取的最佳工艺条件为提取温度40℃、提取压力15MPa、提取时间3h,在此条件下南五味子挥发油得率为8.2%,鉴定出16个成分.水蒸汽蒸馏法提取南五味子挥发油得率为1.4%,鉴定出24个成分.结论:超临界流体CO2提取南五味子挥发油的得率比水蒸汽蒸馏法高,挥发油的组分和含量均有一定的差异.

  2. Deactivation Studies of Rh/Ce0.8Zr0.2O2 Catalysts in Low Temperature Ethanol Steam Reforming

    Energy Technology Data Exchange (ETDEWEB)

    Platon, Alex; Roh, Hyun-Seog; King, David L.; Wang, Yong

    2007-10-30

    Rapid deactivation of Rh/Ce0.8Zr0.2O2 catalysts in low temperature ethanol steam reforming was studied. A significant build-up of carbonaceous intermediate, instead of carbon deposit, was observed at a lower reaction temperature which was attributed to the rapid catalyst deactivation. Co-feed experiments indicated that acetone and ethylene caused more severe catalyst deactivation than other oxygenates such as acidic acid and acetaldehyde.

  3. A simplified Probabilistic Safety Assesment of a Steam-Methane Reforming Hydrogen Production Plant coupled to a High-Temperature Gas Cooled Nuclear Reactor

    OpenAIRE

    Nelson Edelstein, Pamela; Flores Flores, Alain; Francois Lacouture, Juan Luis

    2005-01-01

    A Probabilistic Safety Assessment (PSA) is being developed for a steam-methane reforming hydrogen production plant linked to a High-Temperature Gas Cooled Nuclear Reactor (HTGR). This work is based on the Japan Atomic Energy Research Institute’s (JAERI) High Temperature Test Reactor (HTTR) prototype in Japan. This study has two major objectives: calculate the risk to onsite and offsite individuals, and calculate the frequency of different types of damage to the complex. A simplified HAZOP...

  4. Geometric Characteristics of Methane Steam Reforming with Low Temperature Heat Source

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Gahui; Yun, Jinwon; Yu, Sangseok [Chungnam Nat’l Univ., Daejeon (Korea, Republic of)

    2016-12-15

    In a hybrid fuel cell system, low-temperature reforming technology, which uses waste heat as a heat source, is applied to improve system efficiency. A low temperature reformer is required to optimize geometry in low thermal conditions so that the reformer can achieve the proper methane conversion rate. This study analyzed internal temperature distributions and the reaction patterns of a reformer by considering the change of the shape factor on the limited heat supply condition. Unlike the case of a high temperature reformer, analysis showed that the reaction of a low temperature reformer takes place primarily in the high temperature region of the reactor exit. In addition, it was confirmed that the efficiency can be improved by reducing the GHSV (gas hourly space velocity) or increasing the heat transfer area in the radial direction. Through reacting characteristic analysis, according to change of the aspect ratio, it was confirmed that a low temperature reformer can improve the efficiency by increasing the heat transfer in the radial direction, rather than in the longitudinal direction.

  5. High performance steam development

    Energy Technology Data Exchange (ETDEWEB)

    Duffy, T.; Schneider, P. [Solar Turbines Inc., San Diego, CA (United States)

    1995-10-01

    Over 30 years ago U.S. industry introduced the world`s highest temperature (1200{degrees}F at 5000 psig) and most efficient power plant, the Eddystone coal-burning steam plant. The highest alloy material used in the plant was 316 stainless steel. Problems during the first few years of operation caused a reduction in operating temperature to 1100{degrees}F which has generally become the highest temperature used in plants around the world. Leadership in high temperature steam has moved to Japan and Europe over the last 30 years.

  6. Kinetics of Zr-alloy cladding oxidation in the mixture of air and steam at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyung Tae; Park, Kwang Heon; Park, Joo Young [Kyunghee University, Yongin (Korea, Republic of)

    2012-05-15

    In Fukushima Daiichi Nuclear Power Plant accident, No.4 plant was exploded by hydrogen explosion. There was a strong speculation about the possibility of the reaction between the overheated fuels and the steam-air mixture in the storage pool. Later, it turned out to be due to the hydrogen leaked from No.3 plant. However, the reaction of the hot fuels with the steam-air mixture became an important issue. There have been a lot of data accumulated about Zr-alloy interaction with steam. However, Zr-alloy interactions with air and steam-air mixtures have not been studied relatively much. In this study, we measured the oxidation kinetics of Zry-4 and Zirlo claddings in air, and steam-air mixtures, and analyzed the kinetics

  7. 川芎水蒸气蒸馏和超临界CO2提取物化学成分的GC-MS分析鉴别%GC-MS Analysis and Determination of Chemical Components of the Extracts from Ligusticum Chuanxiong Hort.by Steam Distillation and Supercritical CO2 Extraction

    Institute of Scientific and Technical Information of China (English)

    曾志; 谢润乾; 谭丽贤; 张涛

    2011-01-01

    The chemical components of Ligusticum chuanxiong Hort. Were extracted by steam distillation and supercritical C02 extraction, and analyzed by combined capillary gas chromatography-mass spectrometry(GC-MS). Thirty and thirty four compounds were identified, respectively, and their relative contents were determined. This study revealed that the major components of L chuanxiong Hort. By steam distillation and supercritical CO2 extraction were (Z) -ligustilide. The chemical components from L chuanxiong Hort. Extracted by supercritical CO2 extraction possessed more bioactive substances such as butylphthalide, butylidene phthalide, senkyunolide A, (Z)-ligustilide, (E)-ligustilide and senkyunobde I. However, the components from L chuanxiong Hort. Extracted by steam distillation contained more terpenes except for the bioactive substances. Therefore, supercritical CO2 extraction has more productivity than steam distillation for the extraction of the bioactive substances from L chuanxiong Hort. Through the interpretation and summarization of the regular patterns of the lactones with unsaturated and saturated side chains from L. Chuanxiong Hort. , the structures of the lactones with unsaturated side chain such as (Z)-ligustilide, (E)-ligustilide, butylidene phthalide and senkyunolide I as well as the lactones with saturated side chain such as butylphthalide and senkyunolide A have been determined.%用水蒸气蒸馏和超临界CO2提取方法对川芎药材中的化学成分进行提取,用气相色谱-质谱联用技术(GC-MS)对提取物进行分析,分别鉴定出30和34个化合物,测定了其相对含量.结果表明,水蒸气蒸馏和超临界CO2提取物的主要成分均为(Z)-藁本内酯.超临界CO2提取方法能提取出较多的川芎药效物质,如丁基酞内酯、丁烯基酞内酯、川芎内酯A、(Z)-藁本内酯、(E)-藁本内酯和川芎内酯I.而水蒸气蒸馏提取物中除了川芎药效物质外,还含有较多的萜烯类化

  8. Supercritical Extraction of Lycopene from Tomato Industrial Wastes with Ethane

    OpenAIRE

    Mendes, Rui L.; Cristino, Ana F.; Nobre, Beatriz P.; Luisa Gouveia; António F. Palavra; Patricia G. S. Matos

    2012-01-01

    Supercritical fluid extraction of all-E-lycopene from tomato industrial wastes (mixture of skins and seeds) was carried out in a semi-continuous flow apparatus using ethane as supercritical solvent. The effect of pressure, temperature, feed particle size, solvent superficial velocity and matrix initial composition was evaluated. Moreover, the yield of the extraction was compared with that obtained with other supercritical solvents (supercritical CO2...

  9. Supercritical Extraction of Lycopene from Tomato Industrial Waste with Ethane

    OpenAIRE

    Nobre, Beatriz P.; Gouveia, L.; Patricia G. S. Matos; Cristino, Ana F.; António F. Palavra; Mendes, Rui L.

    2012-01-01

    Supercritical fluid extraction of all-E-lycopene from tomato industrial wastes (mixture of skins and seeds) was carried out in a semi-continuous flow apparatus using ethane as supercritical solvent. The effect of pressure, temperature, feed particle size, solvent superficial velocity and matrix initial composition was evaluated. Moreover, the yield of the extraction was compared with that obtained with other supercritical solvents (supercritical CO2 and a near critical mixture of ethane and p...

  10. Investigation of temperature fluctuation phenomena in a stratified steam-water two-phase flow in a simulating pressurizer spray pipe of a pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Miyoshi, Koji, E-mail: miyoshi.koj@inss.co.jp; Takenaka, Nobuyuki; Ishida, Taisuke; Sugimoto, Katsumi

    2017-05-15

    Highlights: • Thermal hydraulics phenomena were discussed in a spray pipe of pressurizer. • Temperature fluctuation was investigated in a stratified steam-water two-phase. • Remarkable liquid temperature fluctuations were observed in the liquid layer. • The observed temperature fluctuations were caused by the internal gravity wave. • The temperature fluctuations decreased with increasing dissolved oxygen. - Abstract: Temperature fluctuation phenomena in a stratified steam-water two-phase flow in a horizontal rectangular duct, which simulate a pressurizer spray pipe of a pressurized water reactor, were studied experimentally. Vertical distributions of the temperature and the liquid velocity were measured with water of various dissolved oxygen concentrations. Large liquid temperature fluctuations were observed when the water was deaerated well and dissolved oxygen concentration was around 10 ppb. The large temperature fluctuations were not observed when the oxygen concentration was higher. It was shown that the observed temperature fluctuations were caused by the internal gravity wave since the Richardson numbers were larger than 0.25 and the temperature fluctuation frequencies were around the Brunt-Väisälä frequencies in the present experimental conditions. The temperature fluctuations decreased by the non-condensable gas since the non-condensable gas suppressed the condensation and the temperature difference in the liquid layer was small.

  11. THE EFFECT OF SYSTEM TEMPERATURE AND PRESSURE ON THE FLUID-DYNAMIC BEHAVIOR OF THE SUPERCRITICAL ANTISOLVENT MICRONIZATION PROCESS: A NUMERICAL APPROACH

    Directory of Open Access Journals (Sweden)

    R. A. Almeida

    Full Text Available Abstract The Supercritical Antisolvent (SAS technique allows for the precipitation of drugs and biopolymers in nanometer size in a wide range of industrial applications, while guaranteeing the physical and chemical integrity of such materials. However, a suitable combination of operating parameters is needed for each type of solute. The knowledge of fluid dynamics behavior plays a key role in the search for such parameter combinations. This work presents a numerical study concerning the impact of operating temperature and pressure upon the physical properties and mixture dynamics within the SAS process, because in supercritical conditions the radius of the droplets formed exhibits great sensitivity to these variables. For the conditions analyzed, to account for the heat of mixture in the energy balance, subtle variations in the temperature fields were observed, with almost negligible pressure drop. From analyses of the intensity of segregation, there is an enhancement of the mixture on the molecular scale when the system is operated at higher pressure. This corroborates experimental observations from the literature, related to smaller diameters of particles under higher pressures. Hence, the model resulted in a versatile tool for selecting conditions that may promote a better control over the performance of the SAS process.

  12. 余热锅炉蒸汽温度串级自动调节%Cascade Automatic Regulation for the Steam Temperature of Heat Recovery Boiler

    Institute of Scientific and Technical Information of China (English)

    陈敏

    2013-01-01

    Through analysis and research on the characteristics of the steam system in heat recovery boiler,it is determined that to select temperature of the inlet flue gas,steam flow,and main steam temperature as the control parameters for the cascade control system of main steam ; and the method has been verified in practical productive system.The practice indicates that this control system achieves better regulation effect for heat recovery boiler of which the load is easily affected by external factors and with frequent fluctuations.%通过对余热锅炉蒸汽系统特性的分析和研究,确定了余热锅炉进口烟气温度、蒸汽流量及主汽温度作为主蒸汽串级调节系统的控制参数,并在实际生产系统中进行检验.实际应用表明,该调节系统在负荷受外界因素影响较大、波动频繁的余热锅炉上能达到较好的调节效果.

  13. Procedure of calculation of the spatial distribution of temperatures and heat fluxes in the steam generator of a nuclear power installation with an RBEC fast-neutron reactor

    Science.gov (United States)

    Frolov, A. A.; Sedov, A. A.

    2016-08-01

    A method for combined 3D/1D-modeling of thermohydraulics of a once-through steam generator (SG) based on the joint analysis of three-dimensional thermo- and hydrodynamics of a single-phase heating coolant in the intertube space and one-dimensional thermohydraulics of steam-generating channels (tubes) with the use of well-known friction and heat-transfer correlations under various boiling conditions is discussed. This method allows one to determine the spatial distribution of temperatures and heat fluxes of heat-exchange surfaces of SGs with a single-phase heating coolant in the intertube space and with steam generation within tubes. The method was applied in the analytical investigation of typical operation of a once-through SG of a nuclear power installation with an RBEC fast-neutron heavy-metal reactor that is being designed by Kurchatov Institute in collaboration with OKB GIDROPRESS and Leipunsky Institute of Physics and Power Engineering. Flow pattern and temperature fields were obtained for the heavy-metal heating coolant in the intertube space. Nonuniformities of heating of the steam-water coolant in different heat-exchange tubes and nonuniformities in the distribution of heat fluxes at SG heat-exchange surfaces were revealed.

  14. Development of tubes and pipe for ultra-supercritical power plant boilers. Chocho rinkaiatsu boira yo kokan no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Naoi, H.; Mimura, H.; Ogami, M.; Sakakibara, M.; Araki, S.; Sogo, Y.; Ogawa, T.; Sakurai, H. (Nippon Steel Corp., Tokyo (Japan)); Fujita, T. (Tokyo Univ. (Japan))

    1992-11-30

    For aiming to improve the power plant efficiency for a purpose of the energy saving, in recent years, the steam condition of the boilers has become to be supercritical in a degree of the high temperature 566[degree]C[times] high pressure 246 atm. For protecting the global environment, the extensive researches for the further improvement of power plant efficiency are under way in many countries, and the immediate targets of the steam condition for boilers are 316 atm [times]593[degree]C while the final targets are ultra-supercritical as 352 atm [times]649[degree]C. In order to realize the plant which can withstand these conditions, the Nippon Steel Corp. has been conducting a development of the materials which can withstand the high temperature and pressure. Those are the ferritic steel 9Cr-0.5Mo-1.8W-Nb-V (NF616) and the austenitic steel 20Cr-25Ni-1.5Mo-Nb-Ti-N (NF709). The creep rupture strength of the former steel at 600[degree]C is equal to or higher than that of existing 18-8 austenitic stainless steel, while the creep rupture strength of the latter steel at 700[degree]C[times] 100,000 hours is 88MPa or above. The development of these 2 kinds of tubes and pipes for the ultra-supercritical boilers is described. 7 refs., 14 figs., 3 tabs.

  15. Independent Research and Design of 600-MW Supercritical CFB Boiler

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In order to further develop and improve the technologies for large-capacity supercritical CFB boiler, the key technologies for large CFB boiler were systematically studied, based on the development of first domestically-made 210-MW and 330-MW CFB boilers. The scheme of 600-MW supercritical CFB boiler was designed, including the furnace structure, key components, steam-water system and auxiliary systems, which laid a technical foundation for the engineering applications.

  16. 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

  17. Solar steam generation: Steam by thermal concentration

    Science.gov (United States)

    Shang, Wen; Deng, Tao

    2016-09-01

    The solar-driven generation of water steam at 100 °C under one sun normally requires the use of optical concentrators to provide the necessary energy flux. Now, thermal concentration is used to raise the vapour temperature to 100 °C without the need for costly optical concentrators.

  18. Status on the Component Models Developed in the Modelica Framework: High-Temperature Steam Electrolysis Plant & Gas Turbine Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Suk Kim, Jong [Idaho National Lab. (INL), Idaho Falls, ID (United States); McKellar, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bragg-Sitton, Shannon M. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Boardman, Richard D. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-10-01

    This report has been prepared as part of an effort to design and build a modeling and simulation (M&S) framework to assess the economic viability of a nuclear-renewable hybrid energy system (N-R HES). In order to facilitate dynamic M&S of such an integrated system, research groups in multiple national laboratories have been developing various subsystems as dynamic physics-based components using the Modelica programming language. In fiscal year (FY) 2015, Idaho National Laboratory (INL) performed a dynamic analysis of two region-specific N-R HES configurations, including the gas-to-liquid (natural gas to Fischer-Tropsch synthetic fuel) and brackish water reverse osmosis desalination plants as industrial processes. In FY 2016, INL has developed two additional subsystems in the Modelica framework: a high-temperature steam electrolysis (HTSE) plant and a gas turbine power plant (GTPP). HTSE has been proposed as a high priority industrial process to be integrated with a light water reactor (LWR) in an N-R HES. This integrated energy system would be capable of dynamically apportioning thermal and electrical energy (1) to provide responsive generation to the power grid and (2) to produce alternative industrial products (i.e., hydrogen and oxygen) without generating any greenhouse gases. A dynamic performance analysis of the LWR/HTSE integration case was carried out to evaluate the technical feasibility (load-following capability) and safety of such a system operating under highly variable conditions requiring flexible output. To support the dynamic analysis, the detailed dynamic model and control design of the HTSE process, which employs solid oxide electrolysis cells, have been developed to predict the process behavior over a large range of operating conditions. As first-generation N-R HES technology will be based on LWRs, which provide thermal energy at a relatively low temperature, complementary temperature-boosting technology was suggested for integration with the

  19. Anti-corrosive Conversion Coating on Aluminium Alloys Using High Temperature Steam

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    chemistries based on pH and oxidizing capabilities. Treatment is carried out in an autoclave at a temperature of 110 – 112 °C and pressure of 5 Psi for varying times. The growth and composition of the oxide layer was investigated in detail as a function of microstructure using GD-OES, FEG-SEM, EDX, FIB...

  20. Obtaining of gas, liquid, and upgraded solid fuel from brown coals in supercritical water

    Science.gov (United States)

    Vostrikov, A. A.; Fedyaeva, O. N.; Dubov, D. Yu.; Shishkin, A. V.; Sokol, M. Ya.

    2013-12-01

    Two new conversion methods of brown coals in water steam and supercritical water (SCW) are proposed and investigated. In the first method, water steam or SCW is supplied periodically into the array of coal particles and then is ejected from the reactor along with dissolved conversion products. The second method includes the continuous supply of water-coal suspension (WCS) into the vertically arranged reactor from above. When using the proposed methods, agglomeration of coal particles is excluded and a high degree of conversion of coal into liquid and gaseous products is provided. Due to the removal of the main mass of oxygen during conversion in the composition of CO2, the high heating value of fuels obtained from liquid substantially exceeds this characteristic of starting coal. More than half of the sulfur atoms transfer into H2S during the SCW conversion already at a temperature lower than 450°C.

  1. Multi-model Predictive Control of Ultra-supercritical Coal-fired Power Unit

    Institute of Scientific and Technical Information of China (English)

    Guoliang Wang; Weiwu Yan; Shihe Chen; Xi Zhang; Huihe Shao

    2014-01-01

    The control of ultra-supercritical (USC) power unit is a difficult issue for its characteristic of the nonlinearity, large dead time and coupling of the unit. In this paper, model predictive control (MPC) based on multi-model and double layered optimization is introduced for coordinated control of USC unit. The linear programming (LP) com-bined with quadratic programming (QP) is used in steady optimization for computation of the ideal value of dynamic optimization. Three inputs (i.e. valve opening, coal flow and feedwater flow) are employed to control three outputs (i.e. load, main steam temperature and main steam pressure). The step response models for the dynamic matrix control (DMC) are constructed using the three inputs and the three outputs. Piecewise models are built at selected operation points. Double-layered multi-model predictive controller is implemented in sim-ulation with satisfactory performance.

  2. Effects of temperature and pressure on the performance of a solid oxide fuel cell running on steam reformate of kerosene

    Energy Technology Data Exchange (ETDEWEB)

    Chick, Lawrence A.; Marina, Olga A.; Coyle, Christopher A.; Thomsen, Edwin C.

    2013-08-15

    A button solid oxide fuel cell with a La0.6Sr0.4Co0.2Fe0.8O3 cathode and a nickel-YSZ anode was tested over a range of temperatures from 650 to 800°C and a range of pressures from 101 to 724 kPa. The fuel was simulated steam-reformed kerosene and the oxidant was air. The observed increases in open circuit voltages (OCV) were accurately predicted by the Nernst equation. Kinetics also increased, although the power boost due to kinetics was about two thirds as large as the boost due to OCV. The total power boost in going from 101 to 724 kPa at 750°C and 0.8 volts was 66%. Impedance spectroscopy demonstrated a significant decrease in electrodic losses at elevated pressures. Complex impedance spectra were dominated by a combination of low frequency processes that decreased markedly with increasing pressure. A composite of high-frequency processes also decreased with pressure, but to a lesser extent. An empirical algorithm that accurately predicts the increased fuel cell performance at elevated pressures was developed for our results and was also suitable for some, but not all, data reported in the literature.

  3. Study of oxide and α-Zr(O) growth kinetics from high temperature steam oxidation of Zircaloy-4 cladding

    Science.gov (United States)

    Sawarn, Tapan K.; Banerjee, Suparna; Samanta, Akanksha; Rath, B. N.; Kumar, Sunil

    2015-12-01

    Oxidation kinetics of Zircaloy-4 cladding of fuel pins of Indian pressurized heavy water reactors (IPHWRs) under a simulated loss of coolant accident (LOCA) condition was investigated. The kinetic rate constants for the oxide and oxygen stabilized α-Zr phase growth were established from the isothermal metal-steam reaction at high temperatures (900-1200 °C) with soaking periods in the range of 60-900 s. Oxide and α-Zr(O) layer thickness were measured to derive the respective growth rates. The observed rates obeyed a parabolic law and Arrhenius expressions of rate constants were established. Percentage equivalent clad reacted (%ECR) was calculated using Baker-Just equation. Hydrogen estimation was carried out on the oxidized samples using inert gas fusion technique. The hydrogen pick up was found to be in the range 10-30 ppm. The measured values of oxide and α-Zr(O) layer thickness were compared with the results obtained using OXYCON, an indigenously developed model. The model predicts the oxide growth reasonably well but under predicts the α-Zr(O) growth significantly at thickness values higher than 80 μm.

  4. 升温升压过程对聚丙烯在超临界水中降解的影响%Effect of Increasing Course of Temperature and Pressure on Polypropylene Degradation in Supercritical Water

    Institute of Scientific and Technical Information of China (English)

    苏磊; 吴学华; 刘秀茹; 陈丽英; 陈克宇; 洪时明

    2007-01-01

    The effect of increasing course of temperature and pressure on polypropylene (PP) degradation in supercritical water was investigated for developing a process of recycling waste plastic. A group of experiments was carried out in a reaction system at a pressure of 26MPa, temperature of 380℃ or 400℃ for 30min, 70min, and 120main by Course One (the increasing course of temperature and pressure is via gaseous regions to supercritical regions), and the other group was carried out at corresponding holding conditions by Course Two (the increasing course of temperature and pressure is via liquid regions to supercritical regions). The time of the increasing courses was about 30min. Products were analyzed by Ostward-type viscometer, gaseous chromatography, and mass spectrometers (GC/MS). Characterization results suggested that different increasing courses of temperature and pressure would give rise to different results, although they were treated under the similar holding conditions. It was also found that Course Two was more effective on PP degradation in supercritical water.

  5. Energetic approach of biomass hydrolysis in supercritical water.

    Science.gov (United States)

    Cantero, Danilo A; Vaquerizo, Luis; Mato, Fidel; Bermejo, M Dolores; Cocero, M José

    2015-03-01

    Cellulose hydrolysis can be performed in supercritical water with a high selectivity of soluble sugars. The process produces high-pressure steam that can be integrated, from an energy point of view, with the whole biomass treating process. This work investigates the integration of biomass hydrolysis reactors with commercial combined heat and power (CHP) schemes, with special attention to reactor outlet streams. The innovation developed in this work allows adequate energy integration possibilities for heating and compression by using high temperature of the flue gases and direct shaft work from the turbine. The integration of biomass hydrolysis with a CHP process allows the selective conversion of biomass into sugars with low heat requirements. Integrating these two processes, the CHP scheme yield is enhanced around 10% by injecting water in the gas turbine. Furthermore, the hydrolysis reactor can be held at 400°C and 23 MPa using only the gas turbine outlet streams.

  6. High-temperature degradation and protection of ferritic and austenitic steels in steam generators

    Science.gov (United States)

    Martínez-Villafañe, A.; Almeraya-Calderón, M. F.; Gaona-Tiburcio, C.; Gonzalez-Rodriguez, J. G.; Porcayo-Calderón, J.

    1998-02-01

    The useful life of superheaters and reheaters of power stations which use heavy fuel oil is shortened and their continuous service is inhibited by corrosion (fireside) and creep-type problems. The increase of corrosion attack on boilers is caused by the presence of fuel ash deposits containing mainly vanadium, sodium, and sulfur which form low-melting-point compounds. The tubes are exposed to the action of high stresses and high temperatures, producing the so-called “creep damage.” In this work, two kinds of results are reported: lab and field studies using a 2.25Cr-1Mo steel. The laboratory work was in turn divided into two parts. In the first, the steel was exposed to the action of natural ash deposits in oxidant atmospheres at 600 ° for 24 h. In the second part, tensile specimens were creep tested in Na2SO4, V2O5, and their mixture over a temperature range of 580 to 620 °. In the field work, components of a power station were coated with different types of nickel-and iron-base coatings containing chromium, Fe-Cr, and Fe-Si using the powder flame spraying technique. After testing, the coated tubes were analyzed using electron microscopy. The results showed that all the coating systems had good corrosion resistance, especially those containing silicon or chromium.

  7. Ultra-high temperature steam corrosion of complex silicates for nuclear applications: A computational study

    Science.gov (United States)

    Rashkeev, Sergey N.; Glazoff, Michael V.; Tokuhiro, Akira

    2014-01-01

    Stability of materials under extreme conditions is an important issue for safety of nuclear reactors. Presently, silicon carbide (SiC) is being studied as a cladding material candidate for fuel rods in boiling-water and pressurized water-cooled reactors (BWRs and PWRs) that would substitute or modify traditional zircaloy materials. The rate of corrosion of the SiC ceramics in hot vapor environment (up to 2200 °C) simulating emergency conditions of light water reactor (LWR) depends on many environmental factors such as pressure, temperature, viscosity, and surface quality. Using the paralinear oxidation theory developed for ceramics in the combustion reactor environment, we estimated the corrosion rate of SiC ceramics under the conditions representing a significant power excursion in a LWR. It was established that a significant time - at least 100 h - is required for a typical SiC braiding to significantly degrade even in the most aggressive vapor environment (with temperatures up to 2200 °C) which is possible in a LWR at emergency condition. This provides evidence in favor of using the SiC coatings/braidings for additional protection of nuclear reactor rods against off-normal material degradation during power excursions or LOCA incidents. Additionally, we discuss possibilities of using other silica based ceramics in order to find materials with even higher corrosion resistance than SiC. In particular, we found that zircon (ZrSiO4) is also a very promising material for nuclear applications. Thermodynamic and first-principles atomic-scale calculations provide evidence of zircon thermodynamic stability in aggressive environments at least up to 1535 °C.

  8. Advanced 12% chromium steel and its application to ultra-supercritical turbine. Chocho rinkaiatsu turbine eno kairyo 12 kuromuko no tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Hadano, Y.; Kubota, T.; Yamada, M. (Toshiba Corp., Tokyo (Japan))

    1993-05-01

    Introduction of high-pressure and high-temperature steam into the turbine directly contributes to the improvement of thermal efficiency of the thermal power plant. The phase 1 of the ultra-supercritical (USC) turbine with steam pressure of 31MPa or more uses the steam of 593[degree]C level which is about 30[degree]C higher than that used for the phase 0. In order to realize high-pressure and high-temperature steam conditions, it is indispensable to improve high-temperature strength such as creep rupture strength of major parts of the turbine. This report describes the development of heat-resistant materials used for this purpose, and, in particular, advanced 12% chromium steel used for high-temperature rotors and blades. About 1.3 times creep rupture strength of the conventional 12Cr has been obtained by CrMoVWNbN steel with optimized alloying element volume and W addition. Moreover, advanced 12Cr cast steel developed for the turbine casing and steam valves, present state of the development of materials for clamping bolts, and improved points in turbine design to realize high-pressure and high-temperature conditions are outlined. 5 refs., 4 figs., 1tab.

  9. Corrosion in Supercritical carbon Dioxide: Materials, Environmental Purity, Surface Treatments, and Flow Issues

    Energy Technology Data Exchange (ETDEWEB)

    Sridharan, Kumar; Anderson, Mark

    2013-12-10

    The supercritical CO{sub 2} Brayton cycle is gaining importance for power conversion in the Generation IV fast reactor system because of its high conversion efficiencies. When used in conjunction with a sodium fast reactor, the supercritical CO{sub 2} cycle offers additional safety advantages by eliminating potential sodium-water interactions that may occur in a steam cycle. In power conversion systems for Generation IV fast reactors, supercritical CO{sub 2} temperatures could be in the range of 30°C to 650°C, depending on the specific component in the system. Materials corrosion primarily at high temperatures will be an important issue. Therefore, the corrosion performance limits for materials at various temperatures must be established. The proposed research will have four objectives centered on addressing corrosion issues in a high-temperature supercritical CO{sub 2} environment: Task 1: Evaluation of corrosion performance of candidate alloys in high-purity supercritical CO{sub 2}: The following alloys will be tested: Ferritic-martensitic Steels NF616 and HCM12A, austenitic alloys Incoloy 800H and 347 stainless steel, and two advanced concept alloys, AFA (alumina forming austenitic) steel and MA754. Supercritical CO{sub 2} testing will be performed at 450°C, 550°C, and 650°C at a pressure of 20 MPa, in a test facility that is already in place at the proposing university. High purity CO{sub 2} (99.9998%) will be used for these tests. Task 2: Investigation of the effects of CO, H{sub 2}O, and O{sub 2} impurities in supercritical CO{sub 2} on corrosion: Impurities that will inevitably present in the CO{sub 2} will play a critical role in dictating the extent of corrosion and corrosion mechanisms. These effects must be understood to identify the level of CO{sub 2} chemistry control needed to maintain sufficient levels of purity to manage corrosion. The individual effects of important impurities CO, H{sub 2}O, and O{sub 2} will be investigated by adding them

  10. Low Temperature and H2 Selective Catalysts for Ethanol Steam Reforming

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Hyun-Seog; Wang, Yong; King, David L.; Platon, Alex; Chin, Ya-Huei

    2006-04-01

    Supported Rh catalysts have been developed for selective H2 production at low temperatures. Ethanol dehydration is favorable over either acidic or basic supports such as γ-Al2O3 and MgAl2O4, while ethanol dehydrogenation is more favorable over neutral supports. A series of CeO2-ZrO2 supports with various CeO2/ZrO2 ratios were prepared by a co-precipitation method and Rh was impregnated on the as-synthesized support to achieve a strong metal to support interaction (SMSI). 2%Rh/Ce0.8Zr0.2O2 catalyst exhibited the highest H2 yield at 450oC among the various supported Rh catalysts evaluated in this study. This is mainly due to a favored reaction pathway via ethanol dehydrogenation to form the acetaldehyde intermediate, and both the strong interaction between Rh and Ce0.8Zr0.2O2 and the high oxygen storage capacity of Ce0.8Zr0.2O2 which favors oxidation of acetaldehyde decomposition products

  11. Feasibility Study of Supercritical Light Water Cooled Fast Reactors for Actinide Burning and Electric Power Production

    Energy Technology Data Exchange (ETDEWEB)

    Mac Donald, Philip Elsworth; Buongiorno, Jacopo; Davis, Cliff Bybee; Weaver, Kevan Dean

    2002-01-01

    The use of supercritical temperature and pressure light water as the coolant in a direct-cycle nuclear reactor offers potential for considerable plant simplification and consequent capital and O&M cost reduction compared with current light water reactor (LWR) designs. Also, given the thermodynamic conditions of the coolant at the core outlet (i.e. temperature and pressure beyond the water critical point), very high thermal efficiencies of the power conversion cycle are possible (i.e. up to 46%). Because no change of phase occurs in the core, the need for steam separators and dryers as well as for BWR-type recirculation pumps is eliminated, which, for a given reactor power, results in a substantially shorter reactor vessel than the current BWRs. Furthermore, in a direct cycle the steam generators are not needed. If a tight fuel rod lattice is adopted, it is possible to significantly reduce the neutron moderation and attain fast neutron energy spectrum conditions. In this project a supercritical water reactor concept with a simple, blanket-free, pancake-shaped core will be developed. This type of core can make use of either fertile or fertile-free fuel and retain the hard spectrum to effectively burn plutonium and minor actinides from LWR spent fuel while efficiently generating electricity.

  12. Processing of Advanced Cast Alloys for A-USC Steam Turbine Applications

    Science.gov (United States)

    Jablonski, Paul D.; Hawk, Jeffery A.; Cowen, Christopher J.; Maziasz, Philip J.

    2012-02-01

    The high-temperature components within conventional supercritical coal-fired power plants are manufactured from ferritic/martensitic steels. To reduce greenhouse-gas emissions, the efficiency of pulverized coal steam power plants must be increased to as high a temperature and pressure as feasible. The proposed steam temperature in the DOE/NETL Advanced Ultra Supercritical power plant is high enough (760°C) that ferritic/martensitic steels will not work for the majority of high-temperature components in the turbine or for pipes and tubes in the boiler due to temperature limitations of this class of materials. Thus, Ni-based superalloys are being considered for many of these components. Off-the-shelf forged nickel alloys have shown good promise at these temperatures, but further improvements can be made through experimentation within the nominal chemistry range as well as through thermomechanical processing and subsequent heat treatment. However, cast nickel-based superalloys, which possess high strength, creep resistance, and weldability, are typically not available, particularly those with good ductility and toughness that are weldable in thick sections. To address those issues related to thick casting for turbine casings, for example, cast analogs of selected wrought nickel-based superalloys such as alloy 263, Haynes 282, and Nimonic 105 have been produced. Alloy design criteria, melt processing experiences, and heat treatment are discussed with respect to the as-processed and heat-treated microstructures and selected mechanical properties. The discussion concludes with the prospects for full-scale development of a thick section casting for a steam turbine valve chest or rotor casing.

  13. Experimental and numerical simulations of bottom hole temperature and pre-ssure distributions of supercritical CO2 jet for well-drilling

    Institute of Scientific and Technical Information of China (English)

    王瑞和; 霍洪俊; 黄志远; 宋慧芳; 倪红坚

    2014-01-01

    The supercritical carbon dioxide (SC-CO2) drilling is a novel drilling technique developed in recent years. A detailed study of temperature and pressure distributions of the SC-CO2 jet on the bottom of a well is essensial to the SC-CO2 drilling. In this paper, the distributions of pressure and temperature on the bottom of the hole during the SC-CO2 jet drilling are simulated experimentally and numerically, and the impacts of the nozzle diameter, the jet length, and the inlet pressure of the SC-CO2 jet are analyzed. It is shown that, the bottom hole temperature and pressure increase with the increase of the nozzle diameter, and the bottom hole temperature reduces and the pressure increases first and then decreases with the increase of the jet length, indicating that the jet length has an optimum value. The increase of the inlet pressure can increase the temperature and pressure on the bottom, which has a positive effect on the drilling rate.

  14. Hydrogen production from high moisture content biomass in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Antal, M.J. Jr.; Xu, X. [Univ. of Hawaii, Honolulu, HI (United States). Hawaii Natural Energy Inst.

    1998-08-01

    By mixing wood sawdust with a corn starch gel, a viscous paste can be produced that is easily delivered to a supercritical flow reactor by means of a cement pump. Mixtures of about 10 wt% wood sawdust with 3.65 wt% starch are employed in this work, which the authors estimate to cost about $0.043 per lb. Significant reductions in feed cost can be achieved by increasing the wood sawdust loading, but such an increase may require a more complex pump. When this feed is rapidly heated in a tubular flow reactor at pressures above the critical pressure of water (22 MPa), the sawdust paste vaporizes without the formation of char. A packed bed of carbon catalyst in the reactor operating at about 650 C causes the tarry vapors to react with water, producing hydrogen, carbon dioxide, and some methane with a trace of carbon monoxide. The temperature and history of the reactor`s wall influence the hydrogen-methane product equilibrium by catalyzing the methane steam reforming reaction. The water effluent from the reactor is clean. Other biomass feedstocks, such as the waste product of biodiesel production, behave similarly. Unfortunately, sewage sludge does not evidence favorable gasification characteristics and is not a promising feedstock for supercritical water gasification.

  15. Catalyst Deactivation and Regeneration in Low Temperature Ethanol Steam Reforming with Rh/CeO2-ZrO2 Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Hyun-Seog; Platon, Alex; Wang, Yong; King, David L.

    2006-08-01

    Rh/CeO2-ZrO2 catalysts with various CeO2/ZrO2 ratios have been applied to H2 production from ethanol steam reforming at low temperatures. The catalysts all deactivated with time on stream (TOS) at 350 C. The addition of 0.5% K has a beneficial effect on catalyst stability, while 5% K has a negative effect on catalytic activity. The catalyst could be regenerated considerably even at ambient temperature and could recover its initial activity after regeneration above 200 C with 1% O2. The results are most consistent with catalyst deactivation due to carbonaceous deposition on the catalyst.

  16. Steam Turbines

    Science.gov (United States)

    1981-01-01

    Turbonetics Energy, Inc.'s steam turbines are used as power generating systems in the oil and gas, chemical, pharmaceuticals, metals and mining, and pulp and paper industries. The Turbonetics line benefited from use of NASA research data on radial inflow steam turbines and from company contact with personnel of Lewis Research Center, also use of Lewis-developed computer programs to determine performance characteristics of turbines.

  17. Materials for higher steam temperatures (up to 600 deg C) in biomass and waste fired plant. A review of present knowledge; Material foer hoegre aangtemperaturer (upp till 600 grader C) i bio- och avfallseldade anlaeggningar

    Energy Technology Data Exchange (ETDEWEB)

    Staalenheim, Annika; Henderson, Pamela

    2011-02-15

    A goal for the Swedish power industry is to build a demonstration biomass-fired plant with 600 deg C steam data in 2015. Vaermeforsk also has a goal to identify materials that can be used in such a plant. This project involves a survey of present knowledge and published articles concerning materials that are suitable for use in biomass and wastefired plants with steam data up to 600 deg C. The information has been gathered from plants presently in operation, and from field tests previously performed with probes. Plants firing only household waste are excluded. The components considered are waterwalls/furnace walls (affected because of higher steam pressures) and superheaters. Fireside corrosion and steam-side oxidation are dealt with. Candidate materials (or coatings) are suggested and areas for further research have been identified. The purpose of this project is to give state-of-the-art information on what materials could be used in biomass and waste-fired plant to reach a maximum steam temperature of 600 deg C. This report is aimed at suppliers of boilers and materials, energy utility companies and others involved in building new plant with higher steam data. In accordance with the goals of this project: - Materials suitable for use at higher steam temperatures (up to 600 deg C steam) in wood-based biomass and waste-fired plant have been identified. Austenitic stainless steels HR3C, TP 347 HFG and AC66 all have adequate strength, steam-side oxidation and fireside corrosion resistance for use as superheaters. AC66 and HR3C have better steam-side oxidation resistance than TP 347 HFG , but TP 347 HFG has better fireside corrosion resistance. It is recommended that TP 347 HFG be shot-peened on the inside to improve the oxidation resistance if in service with steam temperatures above 580 deg C. - Furnace walls coated with Ni-based alloys or a mixture of Ni- alloy and ceramic show good corrosion resistance at lower temperatures and should be evaluated at higher

  18. Data bank on hydrodynamics, thermal tests and tube temperature regimes of PGV-4 and PVG-1000 natural steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Ageev, A.G.; Vasileva, R.V.; Nigmatulin, B.I.; Titov, V.F.; Tarankov, G.N. [EREC Electrogorsk Research and Engineering Centre of Nuclear Plants Safety, Moscow (Russian Federation)

    1995-12-31

    The data bank was prepared by EREC, OKB `Hydropress` using results of static and dynamic tests of PGV-4 and PGV- 1000 natural steam generators cared out at Kolskaya, Novo-Voronezhskaya, Ugno-Ukrainskaya, Balakov-skaya and Hmelnitskaya NPP within period of 1974-1993. It is destined for making calculation codes verification. (authors).

  19. Enhancing power cycle efficiency for a supercritical Brayton cycle power system using tunable supercritical gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Steven A.; Pickard, Paul S.; Vernon, Milton E.; Radel, Ross F.

    2017-08-29

    Various technologies pertaining to tuning composition of a fluid mixture in a supercritical Brayton cycle power generation system are described herein. Compounds, such as Alkanes, are selectively added or removed from an operating fluid of the supercritical Brayton cycle power generation system to cause the critical temperature of the fluid to move up or down, depending upon environmental conditions. As efficiency of the supercritical Brayton cycle power generation system is substantially optimized when heat is rejected near the critical temperature of the fluid, dynamically modifying the critical temperature of the fluid based upon sensed environmental conditions improves efficiency of such a system.

  20. The effect of flow rate at different pressures and temperatures on cocoa butter extracted from cocoa nib using supercritical carbon dioxide.

    Science.gov (United States)

    Asep, E K; Jinap, S; Russly, A R; Jahurul, M H A; Ghafoor, Kashif; Zaidul, I S M

    2016-05-01

    The effects of flow rate, different pressures and temperatures on cocoa butter extracted from cocoa nib using supercritical carbon dioxide (scCO2) were investigated. The yield was analyzed for total fat content, triacylglycerol (TG) profile, and fatty acid (FA) profile. Extractions were carried out at pressures of 20 and 35 MPa, temperatures of 50 and 60 °C, and CO2 flow rates of 0.5, 1, 2, 4 mL min(-1). The result shows that the yield of cocoa butter extract increased with increasing pressure, temperature, and flow rate and the optimum conditions for the maximum cocoa butter extraction were 35 MPa, 60 °C and 2 mL min(-1), repectively. TGs and FAs were found to be similar in composition to those of cocoa butter obtained by conventional methods. The lower molecular weight TGs and FAs showed higher selectivity compared to higher molecular weight TGs and FAs.

  1. Steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Beckmann, G.; Gilli, P.V.; Fritz, K.; Lippitsch, J.

    1975-12-02

    A steam generator is disclosed which is particularly adapted to be used in nuclear power plants. A casing is provided with an inlet and outlet to receive and discharge a primary heating fluid from which heat is to be extracted. A pair of tube plates extend across the interior of the casing at the region of the inlet and outlet thereof, and a plurality of tubes extend along the interior of the casing and are connected in parallel between the tube plates with all of the tubes having open ends communicating with the inlet and outlet of the casing so that the primary heating fluid will flow through the interior of the tubes while a fluid in the casing at the exterior of the tubes will extract heat from the primary fluid. The casing has between the tubes at the region of the inlet a superheating chamber and at the region of the outlet a preheating chamber and between the latter chambers an evaporating chamber, the casing receiving water through an inlet at the preheating chamber and discharging superheated steam through an outlet at the superheating chamber. A separator communicates with the evaporating chamber to receive a mixture of steam and water therefrom for separating the steam from the water and for delivering the separated steam to the superheating chamber.

  2. Low CO content hydrogen production from oxidative steam reforming of ethanol over CuO-CeO2 catalysts at low-temperature

    Institute of Scientific and Technical Information of China (English)

    Xue; Han; Yunbo; Yu; Hong; He; Jiaojiao; Zhao

    2013-01-01

    CuO-CeO2 catalysts were prepared by a urea precipitation method for the oxidative steam reforming of ethanol at low-temperature.The catalytic performance was evaluated and the catalysts were characterized by inductively coupled plasma atomic emission spectroscopy,X-ray diffraction,temperature-programmed reduction,field emission scanning electron microscopy and thermo-gravimetric analysis.Over CuOCeO2 catalysts,H2 with low CO content was produced in the whole tested temperature range of 250–450 C.The non-noble metal catalyst 20CuCe showed higher H2production rate than 1%Rh/CeO2 catalyst at 300–400 C and the advantage was more obvious after 20 h testing at400 C.These results further confirmed that CuO-CeO2 catalysts may be suitable candidates for low temperature hydrogen production from ethanol.

  3. Using supercritical fluids to refine hydrocarbons

    Science.gov (United States)

    Yarbro, Stephen Lee

    2015-06-09

    A system and method for reactively refining hydrocarbons, such as heavy oils with API gravities of less than 20 degrees and bitumen-like hydrocarbons with viscosities greater than 1000 cp at standard temperature and pressure, using a selected fluid at supercritical conditions. A reaction portion of the system and method delivers lightweight, volatile hydrocarbons to an associated contacting unit which operates in mixed subcritical/supercritical or supercritical modes. Using thermal diffusion, multiphase contact, or a momentum generating pressure gradient, the contacting unit separates the reaction products into portions that are viable for use or sale without further conventional refining and hydro-processing techniques.

  4. Feasibility Study of Supercritical Light Water Cooled Fast Reactors for Actinide Burning and Electric Power Production, 3rd Quarterly Report

    Energy Technology Data Exchange (ETDEWEB)

    Mac Donald, Philip Elsworth

    2002-06-01

    The use of light water at supercritical pressures as the coolant in a nuclear reactor offers the potential for considerable plant simplification and consequent capital and O&M cost reduction compared with current light water reactor (LWR) designs. Also, given the thermodynamic conditions of the coolant at the core outlet (i.e. temperature and pressure beyond the water critical point), very high thermal efficiencies of the power conversion cycle are possible (i.e. up to about 45%). Because no change of phase occurs in the core, the need for steam separators and dryers as well as for BWR-type re-circulation pumps is eliminated, which, for a given reactor power, results in a substantially shorter reactor vessel and smaller containment building than the current BWRs. Furthermore, in a direct cycle the steam generators are not needed.

  5. Steam refining as an alternative to steam explosion.

    Science.gov (United States)

    Schütt, Fokko; Westereng, Bjørge; Horn, Svein J; Puls, Jürgen; Saake, Bodo

    2012-05-01

    In steam pretreatment the defibration is usually achieved by an explosion at the end of the treatment, but can also be carried out in a subsequent refiner step. A steam explosion and a steam refining unit were compared by using the same raw material and pretreatment conditions, i.e. temperature and time. Smaller particle size was needed for the steam explosion unit to obtain homogenous slurries without considerable amounts of solid chips. A higher amount of volatiles could be condensed from the vapour phase after steam refining. The results from enzymatic hydrolysis showed no significant differences. It could be shown that, beside the chemical changes in the cell wall, the decrease of the particle size is the decisive factor to enhance the enzymatic accessibility while the explosion effect is not required.

  6. SUPERCRITICAL FLUID EXTRACTION OF POLYCYCLIC AROMATIC HYDROCARBON MIXTURES FROM CONTAMINATED SOILS

    Science.gov (United States)

    Highly contaminated (with PAHs) topsoils were extracted with supercritical CO2 to determine the feasibility and mechanism of supercritical fluid extraction (SFE). Effect of SCF density, temperature, cosolvent type and amount, and of slurrying the soil with water were ...

  7. Degradation Characteristics of Wood Using Supercritical Alcohols

    Directory of Open Access Journals (Sweden)

    Jeeban Poudel

    2012-11-01

    Full Text Available In this work, the characteristics of wood degradation using supercritical alcohols have been studied. Supercritical ethanol and supercritical methanol were used as solvents. The kinetics of wood degradation were analyzed using the nonisothermal weight loss technique with heating rates of 3.1, 9.8, and 14.5 °C/min for ethanol and 5.2, 11.3, and 16.3 °C/min for methanol. Three different kinetic analysis methods were implemented to obtain the apparent activation energy and the overall reaction order for wood degradation using supercritical alcohols. These were used to compare with previous data for supercritical methanol. From this work, the activation energies of wood degradation in supercritical ethanol were obtained as 78.0–86.0, 40.1–48.1, and 114 kJ/mol for the different kinetic analysis methods used in this work. The activation energies of wood degradation in supercritical ethanol were obtained as 78.0–86.0, 40.1–48.1, and 114 kJ/mol. This paper also includes the analysis of the liquid products obtained from this work. The characteristic analysis of liquid products on increasing reaction temperature and time has been performed by GC-MS. The liquid products were categorized according to carbon numbers and aromatic/aliphatic components. It was found that higher conversion in supercritical ethanol occurs at a lower temperature than that of supercritical methanol. The product analysis shows that the majority of products fall in the 2 to 15 carbon number range.

  8. [A simple apparatus for the determination of the resistance of bioindicators to saturated steam at temperatures less than 100 degrees C., tested with Enterococcus faecium as test microbe].

    Science.gov (United States)

    Spicher, G; Borchers, U; Peters, J

    1991-09-01

    An apparatus is described by means of which the resistance of microbiological indicators to water vapor at temperatures below 100 degrees C can be determined. The apparatus can be assembled from parts generally available in laboratories. The principle of the apparatus consists in the production of water vapor of the desired temperature under conditions of reduced pressure and its recondensation to water after having passed a special chamber. Accordingly, the device consists of a heated round-bottom flask serving as steam generator, an exposure chamber (B), and a condenser (D) attached to a receiver (E). The bioindicators are exposed to the water vapor in the exposure chamber. A bypass located between the steam generator and the condenser allows for continuous operation even when the exposure chamber is opened. The reduced pressure was achieved by means of a waterjet pump and adjusted by two tandem-joined pressure-regulating valves as needed. The apparatus was tested using water vapor of 73, 75 and 77 degrees C, respectively, and bioindicators containing Enterococcus faecium as test organism. In the range of exposure periods in which bioindicators change from the status "all indicators having surviving test organisms" to the status "all indicators free from surviving test organisms" the bioindicators showed D values of 5.7, 4.4 and 2.9 min, respectively. For the temperature dependence of resistance a z value of 12.5 Kelvin resulted.

  9. 超临界CO2萃取穿心莲内酯的实验研究%Supercritical Carbon Dioxide Extraction of Andrographolide from Andrographis paniculata: Effect of the Solvent Flow Rate,Pressure,and Temperature

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Andrographis paniculata Nees has been extensively used for traditional medicine and help against fever,dysentery,diarrhoea,inflammation,and sore throat. In this study,andrographolide,the main component of this plant was extracted from the leaves of A. paniculata using supercritical carbon dioxide. The operating pressures were varied from 7.50 to 20 MPa,the temperatures were varied from 30℃ to 60℃,and the flow rates were varied 3g sample of A. paniculata ground-dried leaves. The measured extraction rate was found to be about 0.0174g of andrographolide per gram of andrographolide present in the leaves per hour of operation. The future studies must focus on the interaction between the various operating parameters such as temperature,pressure,and flow rate of supercritical carbon dioxide.

  10. Water in supercritical carbon dioxide dyeing

    Directory of Open Access Journals (Sweden)

    Zheng Lai-Jiu

    2015-01-01

    Full Text Available This paper investigates the effect of water serving as entrainer on the dyeing of wool fabrics in supercritical carbon dioxide. Compared with previous supercritical dyeing methods, addition of water makes the dyeing process more effective under low temperature and low pressure. During dyeing process, dyestuff can be uniformly distributed on fabrics’s surface due to water interaction, as a result coloration is enhanced while color difference is decreased.

  11. Bio-oil production from biomass via supercritical fluid extraction

    Energy Technology Data Exchange (ETDEWEB)

    Durak, Halil, E-mail: halildurak@yyu.edu.tr [Yuzuncu Yıl University, Vocational School of Health Services, 65080, Van (Turkey)

    2016-04-18

    Supercritical fluid extraction is used for producing bio-fuel from biomass. Supercritical fluid extraction process under supercritical conditions is the thermally disruption process of the lignocellulose or other organic materials at 250-400 °C temperature range under high pressure (4-5 MPa). Supercritical fluid extraction trials were performed in a cylindrical reactor (75 mL) in organic solvents (acetone, ethanol) under supercritical conditions with (calcium hydroxide, sodium carbonate) and without catalyst at the temperatures of 250, 275 and 300 °C. The produced liquids at 300 °C in supercritical liquefaction were analyzed and characterized by elemental, GC-MS and FT-IR. 36 and 37 different types of compounds were identified by GC-MS obtained in acetone and ethanol respectively.

  12. Bio-oil production from biomass via supercritical fluid extraction

    Science.gov (United States)

    Durak, Halil

    2016-04-01

    Supercritical fluid extraction is used for producing bio-fuel from biomass. Supercritical fluid extraction process under supercritical conditions is the thermally disruption process of the lignocellulose or other organic materials at 250-400 °C temperature range under high pressure (4-5 MPa). Supercritical fluid extraction trials were performed in a cylindrical reactor (75 mL) in organic solvents (acetone, ethanol) under supercritical conditions with (calcium hydroxide, sodium carbonate) and without catalyst at the temperatures of 250, 275 and 300 °C. The produced liquids at 300 °C in supercritical liquefaction were analyzed and characterized by elemental, GC-MS and FT-IR. 36 and 37 different types of compounds were identified by GC-MS obtained in acetone and ethanol respectively.

  13. Oxidation behavior of Ti2AlC in the temperature range of 1400 °C-1600 °C in steam

    Science.gov (United States)

    Tang, Chongchong; Steinbrück, Martin; Große, Mirco; Bergfeldt, Thomas; Seifert, Hans Jürgen

    2017-07-01

    The oxidation behavior of bulk Ti2AlC ceramic in steam has been investigated in the temperature range of 1400 °C-1600 °C. The oxidation kinetics followed a sub-parabolic law at the early stage of oxidation, then tended to be a linear law beyond 18 h at 1400 °C, and obeyed a linear law during the whole exposure up to 24 h at 1500 °C. At the initial stage of oxidation at 1400 °C and 1500 °C, randomly Al2TiO5 isolated islands with large elongated grains were observed on the surface. A continuous inner α-Al2O3 layer with a thin discontinuous outer layer of Al2TiO5 formed with prolonged exposure time. Outward diffusion of Ti and C through grain boundaries of the α-Al2O3 scale during steady-state oxidation result in segregation of TiO2 at the grain boundaries of α-Al2O3 and formation of gaseous CO and CO2, respectively. The scale adhesion was reduced in steam compared to that in air due to the accumulation of stresses, and generation of voids at the scale/substrate interface. The mechanical disruption of the oxide scale to relief the stresses contribute to the breakaway oxidation of Ti2AlC at 1400 °C and to the non-protective effect at 1500 °C. The sample was rapidly and completely consumed during isothermal oxidation at 1600 °C accompanied by release of heat and hydrogen. The maximum tolerant temperature of Ti2AlC in steam was approximate 1555 °C, which can be extended via a tailored pre-oxidation process.

  14. Network-based reliability control for superheated steam temperature%基于网络的过热蒸汽温度可靠性控制

    Institute of Scientific and Technical Information of China (English)

    顾伟; 庄宝春; 刘金良

    2014-01-01

    This paper investigates the problem of reliability control for network-based superheated steam temperature control system , taking into account the actuator failure and transmition of the control signal of superheated steam through network .An integrated model for stochastic actuator failure was established , which takes the cascade con-trol as the basic control strategy .By using Lyapunov stability theory and linear matrix inequities ( LMIs) technolo-gy, the randomly and equally divided stability conditions for the system are given , and then the controller design method for superheated steam temperature control system which takes actuator stochastic fault into account was put forward.At last, an application example is provided to demonstrate the effectiveness of the proposed method .%研究了在考虑执行器故障情况下,以及过热汽温的控制信号通过网络进行传输的情况下,过热汽温的温度控制系统的可靠性控制问题。建立了执行器随机故障模型,以串级控制为基本控制策略,利用Lyapunov 稳定性理论和线性矩阵不等式( linear matrix inequities , LMIs)技术,给出了系统随机均分稳定条件,提出了考虑执行器具有随机故障的过热蒸汽控制系统的控制器设计方法。通过仿真实验证明了提出的控制器设计方案的有效性。

  15. Study on Oxygenated Treatment of High-pressure Heater Steam-Liquid Phase Transition Zone for Ultra-Supercritical Units%高压加热器汽液相变区氧化处理技术在超超临界发电机组上的应用

    Institute of Scientific and Technical Information of China (English)

    施国忠; 刘春红

    2015-01-01

    The traditional oxygenated treatment of feedwater jeopardizes operation safety of units due to falling-off of oxide skin of superheater. However, low oxygenated treatment of feedwater can not drastically e-liminate flow accelerated corrosion of feedwater and steam-liquid phase transition zone. After oxygenated treat-ment in steam-liquid phase transition zone of high-pressure heater of ultra-supercritical units, accurate, fixed-point and quantitative oxygenated treatment is achieved and flow accelerated corrosion of phase transition zone for high-pressure heater is successfully eliminated; in the meantime, the risk of oxide skin falling-off of superheater is prevented and the security and economical efficiency of the units are improved. After oxygenat-ed treatment of steam-liquid phase transition zone, conversion speed of the dense Fe2O3 oxide film is fast, Fe concentration of high-pressure heater drainage decreases by 85%and Fe concentration is less than 1μg/L.%传统的给水加氧工艺由于存在过热器氧化皮剥落风险,危及机组安全运行,而给水低氧处理工艺又无法彻底解决给水和汽液相变区流动加速腐蚀的问题。对超超临界发电机组高压加热器汽液相变区采用氧化处理技术,实现精确、定点、定量加氧处理,成功解决了高压加热器汽液相变区的流动加速腐蚀问题,又避免了过热器氧化皮剥落的风险,提高了机组的安全经济性。高加汽液相变区进行氧化处理后,致密的Fe2O3氧化膜转化速度快,高加疏水Fe浓度下降达85%, Fe浓度小于1μg/L。

  16. Solvent adsorption in SFC : Adsorption of methanol under supercritical conditions

    OpenAIRE

    Edström, Emelie

    2015-01-01

    Chromatography is a widely used separation technique including many different modes, for example supercritical fluid chromatography (SFC) which uses a supercritical fluid as mobile phase. A supercritical fluid is achieved when a substance is subjected to a temperature and pressure above the critical point and the boundary between the liquid phase and gas phase is erased. The interest for SFC has increased in recent years, mainly for separation of chiral molecules in the pharmaceutical industr...

  17. Advanced Thermal Storage for Central Receivers with Supercritical Coolants

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Bruce D.

    2010-06-15

    The principal objective of the study is to determine if supercritical heat transport fluids in a central receiver power plant, in combination with ceramic thermocline storage systems, offer a reduction in levelized energy cost over a baseline nitrate salt concept. The baseline concept uses a nitrate salt receiver, two-tank (hot and cold) nitrate salt thermal storage, and a subcritical Rankine cycle. A total of 6 plant designs were analyzed, as follows: Plant Designation Receiver Fluid Thermal Storage Rankine Cycle Subcritical nitrate salt Nitrate salt Two tank nitrate salt Subcritical Supercritical nitrate salt Nitrate salt Two tank nitrate salt Supercritical Low temperature H2O Supercritical H2O Two tank nitrate salt Supercritical High temperature H2O Supercritical H2O Packed bed thermocline Supercritical Low temperature CO2 Supercritical CO2 Two tank nitrate salt Supercritical High temperature CO2 Supercritical CO2 Packed bed thermocline Supercritical Several conclusions have been drawn from the results of the study, as follows: 1) The use of supercritical H2O as the heat transport fluid in a packed bed thermocline is likely not a practical approach. The specific heat of the fluid is a strong function of the temperatures at values near 400 °C, and the temperature profile in the bed during a charging cycle is markedly different than the profile during a discharging cycle. 2) The use of supercritical CO2 as the heat transport fluid in a packed bed thermocline is judged to be technically feasible. Nonetheless, the high operating pressures for the supercritical fluid require the use of pressure vessels to contain the storage inventory. The unit cost of the two-tank nitrate salt system is approximately $24/kWht, while the unit cost of the high pressure thermocline system is nominally 10 times as high. 3) For the supercritical fluids, the outer crown temperatures of the receiver tubes are in the range of 700 to 800 °C. At temperatures of 700 °C and above

  18. Corrosion in supercritical fluids

    Energy Technology Data Exchange (ETDEWEB)

    Propp, W.A.; Carleson, T.E.; Wai, Chen M.; Taylor, P.R.; Daehling, K.W.; Huang, Shaoping; Abdel-Latif, M.

    1996-05-01

    Integrated studies were carried out in the areas of corrosion, thermodynamic modeling, and electrochemistry under pressure and temperature conditions appropriate for potential applications of supercritical fluid (SCF) extractive metallurgy. Carbon dioxide and water were the primary fluids studied. Modifiers were used in some tests; these consisted of 1 wt% water and 10 wt% methanol for carbon dioxide and of sulfuric acid, sodium sulfate, ammonium sulfate, and ammonium nitrate at concentrations ranging from 0.00517 to 0.010 M for the aqueous fluids. The materials studied were Types 304 and 316 (UNS S30400 and S31600) stainless steel, iron, and AISI-SAE 1080 (UNS G10800) carbon steel. The thermodynamic modeling consisted of development of a personal computer-based program for generating Pourbaix diagrams at supercritical conditions in aqueous systems. As part of the model, a general method for extrapolating entropies and related thermodynamic properties from ambient to SCF conditions was developed. The experimental work was used as a tool to evaluate the predictions of the model for these systems. The model predicted a general loss of passivation in iron-based alloys at SCF conditions that was consistent with experimentally measured corrosion rates and open circuit potentials. For carbon-dioxide-based SCFs, measured corrosion rates were low, indicating that carbon steel would be suitable for use with unmodified carbon dioxide, while Type 304 stainless steel would be suitable for use with water or methanol as modifiers.

  19. Application of Smith Controller in Superheater Steam Temperature Control%Smith预估器在过热气温控制中的应用

    Institute of Scientific and Technical Information of China (English)

    于海东; 孙建国; 刘翠兰

    2012-01-01

    To the time-delay control process,the principle of Smith predictor is introduced and analyzed. The new structure of a modified Smith predictor is given particularly. Based on the ITAE criteria, the tuning method of the modified Smith controller's parameters are introduced. Combine with Dalate Power plant #4 unit superheater steam temperature control to inquiry into test method of parameter of Smith controller controlling superheater steam temperature > and carried on comparison and tally up on effect after implementation and normal PID control effect.%针对过程控制滞后的问题,介绍Smith预估器的控制原理和应用,把一种改进的Smith预估控制器应用于发电厂过热气温控制.并利用ITAE优化准则给出了改进Smith预估控制器的参数整定方法.以达拉特发电厂#4机组过热汽温控制为例探讨Smith预估器对过热汽温控制时参数的整定方法,并对实施后的效果与常规PID控制效果进行比较和总结.

  20. Performance of iron-chromium-aluminum alloy surface coatings on Zircaloy 2 under high-temperature steam and normal BWR operating conditions

    Science.gov (United States)

    Zhong, Weicheng; Mouche, Peter A.; Han, Xiaochun; Heuser, Brent J.; Mandapaka, Kiran K.; Was, Gary S.

    2016-03-01

    Iron-chromium-aluminum (FeCrAl) coatings deposited on Zircaloy 2 (Zy2) and yttria-stabilized zirconia (YSZ) by magnetron sputtering have been tested with respect to oxidation weight gain in high-temperature steam. In addition, autoclave testing of FeCrAl-coated Zy2 coupons under pressure-temperature-dissolved oxygen coolant conditions representative of a boiling water reactor (BWR) environment has been performed. Four different FeCrAl compositions have been tested in 700 °C steam; compositions that promote alumina formation inhibited oxidation of the underlying Zy2. Parabolic growth kinetics of alumina on FeCrAl-coated Zy2 is quantified via elemental depth profiling. Autoclave testing under normal BWR operating conditions (288 °C, 9.5 MPa with normal water chemistry) up to 20 days demonstrates observable weight gain over uncoated Zy2 simultaneously exposed to the same environment. However, no FeCrAl film degradation was observed. The 900 °C eutectic in binary Fe-Zr is addressed with the FeCrAl-YSZ system.

  1. High Temperature Co‐Electrolysis of Steam and CO2 in an SOC Stack: Performance and Durability

    DEFF Research Database (Denmark)

    Chen, Ming; Høgh, Jens Valdemar Thorvald; Nielsen, J. U.;

    2013-01-01

    In this work, co‐electrolysis of steam and carbon dioxide was studied in a Topsoe Fuel Cell (TOFC®) 10‐cell stack, containing three different types of Ni/yttria stabilized zirconia (YSZ) electrode supported solid oxide electrolysis cells with a footprint of 12 × 12 cm. The stack was operated at 800...... °C and –0.75 A cm–2 with 60% conversion for a period of 1,000 h. One type of the cells showed no long term degradation but actually activation during the entire electrolysis period, while the other two types degraded. The performance and durability of the different cell types is discussed...

  2. Supercritical Water Mixture (SCWM) Experiment

    Science.gov (United States)

    Hicks, Michael C.; Hegde, Uday G.

    2012-01-01

    The subject presentation, entitled, Supercritical Water Mixture (SCWM) Experiment, was presented at the International Space Station (ISS) Increment 33/34 Science Symposium. This presentation provides an overview of an international collaboration between NASA and CNES to study the behavior of a dilute aqueous solution of Na2SO4 (5% w) at near-critical conditions. The Supercritical Water Mixture (SCWM) investigation, serves as important precursor work for subsequent Supercritical Water Oxidation (SCWO) experiments. The SCWM investigation will be performed in DECLICs High Temperature Insert (HTI) for the purpose of studying critical fluid phenomena at high temperatures and pressures. The HTI includes a completely sealed and integrated test cell (i.e., Sample Cell Unit SCU) that will contain approximately 0.3 ml of the aqueous test solution. During the sequence of tests, scheduled to be performed in FY13, temperatures and pressures will be elevated to critical conditions (i.e., Tc = 374C and Pc = 22 MPa) in order to observe salt precipitation, precipitate agglomeration and precipitate transport in the presence of a temperature gradient without the influences of gravitational forces. This presentation provides an overview of the motivation for this work, a description of the DECLIC HTI hardware, the proposed test sequences, and a brief discussion of the scientific research objectives.

  3. Supercritical CO{sub 2} fluid for chip resistor cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.W.; Chang, R.T.; Lin, W.K.; Lin, R.D.; Liang, M.T.; Yang, J.F.; Wang, J.B.

    1999-09-01

    The cleaning ability of supercritical CO{sub 2} was examined on chip resistors. Extraction analyses were made by atomic absorption spectroscopy and the extent of surface cleaning observed by scanning electron microscopy. Experimental results showed that the flow-cleaning process of supercritical CO{sub 2} possessed the advantages of having a superior cleaning ability and permitting a nondrying step. These characteristics strongly suggest that supercritical CO{sub 2} is a superior alternative to the traditional deionized water used in rinsing chip resistors. Moreover, a higher pressure and temperature can benefit the cleaning ability of this novel supercritical CO{sub 2} cleaning technique.

  4. 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.

  5. Effect of steaming, blanching, and high temperature/high pressure processing on the amino Acid contents of commonly consumed korean vegetables and pulses.

    Science.gov (United States)

    Kim, Su-Yeon; Kim, Bo-Min; Kim, Jung-Bong; Shanmugavelan, Poovan; Kim, Heon-Woong; Kim, So-Young; Kim, Se-Na; Cho, Young-Sook; Choi, Han-Seok; Park, Ki-Moon

    2014-09-01

    In the present report, the effects of blanching, steaming, and high temperature/high pressure processing (HTHP) on the amino acid contents of commonly consumed Korean root vegetables, leaf vegetables, and pulses were evaluated using an Automatic Amino Acid Analyzer. The total amino acid content of the samples tested was between 3.38 g/100 g dry weight (DW) and 21.32 g/100 g DW in raw vegetables and between 29.36 g/100 g DW and 30.55 g/100 g DW in raw pulses. With HTHP, we observed significant decreases in the lysine and arginine contents of vegetables and the lysine, arginine, and cysteine contents of pulses. Moreover, the amino acid contents of blanched vegetables and steamed pulses were more similar than the amino acid contents of the HTHP vegetables and HTHP pulses. Interestingly, lysine, arginine, and cysteine were more sensitive to HTHP than the other amino acids. Partial Least Squares-Discriminate Analyses were also performed to discriminate the clusters and patterns of amino acids.

  6. Drilling to Supercritical Conditions: the Iceland Deep Drilling Project (IDDP).

    Science.gov (United States)

    Elders, W. A.; Fridleifsson, G. O.; Saito, S.

    2001-05-01

    Geothermal wells produce mixtures of water and steam in the range 200-350 C, however the high cost of drilling and completing these wells relative to the cost of oil and gas wells is a hindrance to the geothermal industry worldwide. Rather than trying only to reduce this cost, the Icelandic Deep Drilling Project (IDDP) is trying the approach of increasing the power output per well. Funded by a consortium of energy companies in Iceland, the IDDP plans to drill a series of boreholes, to depths greater than 4 to 5 km. The aim is to produce hydrothermal fluids systems at temperatures of 400-500 C, and to investigate the technical and economic aspects of producing supercritical fluids for use in power generation and other energy intensive processes, such as mineral recovery. The first phase feasibility and site selection study began in March 2001 and drilling of the first deep well is expected to begin in 2003. The IDDP faces difficult technical challenges to drill, complete, sample and maintain wells under hot, and potentially acid, conditions. However the IDDP also presents the opportunity to investigate very high-temperature hydrothermal regimes that have rarely been available for direct study. It will address important scientific issues, ranging from the coupling of magmatic and hydrothermal systems, supercritical phenomena, the transition from brittle to ductile behavior at relatively shallow depths, to land based analogues of submarine hot springs, the black smokers of the mid-ocean ridges. Fortunately, the IDDP industrial consortium is willing, or even anxious, to integrate its engineering activities with scientific investigations. The consortium will seek international participation by scientists and engineers to formulate a strategy to achieve both the engineering and scientific goals of the IDDP.

  7. Minimizing ultraviolet noise due to mis-matches between detector flow cell and post column mobile phase temperatures in supercritical fluid chromatography: effect of flow cell design.

    Science.gov (United States)

    Berger, Terry A

    2014-10-17

    A mis-match between the post-column mobile phase temperature and the UV detector flow cell temperature can cause significant UV noise in supercritical fluid chromatography (SFC). Deviations as little as 5 °C can increase noise as much as 5 times, making the detector unsuited for trace analysis. Two approaches were used to minimize this noise. When a flow cell was in direct thermal contact (metal on metal) with the detector optical bench, the mobile phase temperature was actively controlled to the measured flow cell temperature, by using one of the heat exchangers (HX) in the column compartment. However, with some older, but still widely used flow cell designs, this required repeated, hourly monitoring of the flow cell temperature and repeated manual adjustment of the heat exchanger temperature, due to thermal drift. Flow cell design had a strong influence on susceptibility to this thermally induced noise. Thermally insulating the flow cell from the optical bench made some cells much less susceptible to such thermally induced noise. Five different flow cells, some insulated, some un-insulated, were evaluated. Most had a truncated conical flow path, but one had a cylindrical flow path. Using either approach, the ASTM noise, with a 10mm, 13 μL conical flow cell, could be optimized to ≈0.007 mAU at 2.5 Hz, in SFC, which is very near the 0.006 mAU manufacturer's specification for HPLC. The insulated version of this flow cell required far less optimization, compared to the un-insulated version. At 150 bar, an experimental 3mm, 2 μL flow cell, with only one side insulated, yielded noise slightly too high (≈0.16-0.18 mAU) for trace analysis, at 80 Hz. However, at 200 bar, noise at 80 Hz was noise ratio (S/N) >10. Even partially un-insulated, this flow cell design was much less susceptible to thermally induced noise. Further insulating this flow cell design failed to improve performance.

  8. Welding and assembly process of 1000 MW ultra-supercritical steam turbine generator frame%1000WM超超临界汽轮发电机机座装焊工艺研究

    Institute of Scientific and Technical Information of China (English)

    侯勇; 李明

    2012-01-01

    分析了1000 MW超超临界汽轮发电机定子机座的结构,该汽发定子机座尺寸大、制造难度高.为了满足制造技术要求,提出以汽端和励端分别为基准,机座分两段进行装配焊接,然后再将两段总装的焊接装配方案.有效地控制了装配尺寸,防止焊接变形,确保机座装配质量满足设计要求.%According to stator frame structure analysis of 1000MW Ultra-supercritical turbine generator,this .stator frame with big size would be fabricated very difficult meeting the design standards.This article puts forward a welding assembly proposal: taking turbine end and exciter side as the bases to weld the frame in two separate sections,then to combine the two sections together.The article also discusses measures of controlling assembly size to prevent welding deformation in order to ensure the final welding assembly quality of turbine frame so as to meet the design standards.

  9. Supercritical fluid extraction

    Science.gov (United States)

    Wai, Chien M.; Laintz, Kenneth

    1994-01-01

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated or lipophilic crown ether or fluorinated dithiocarbamate. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

  10. US-UK Phase 3 Task 1 Oxidation in Supercritical Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Gordon R. [National Energy Technology Lab. (NETL), Albany, OR (United States)

    2017-03-20

    A presentation of the US-UK Phase 3 Task 1 Oxidation in Supercritical Fluids. Includes slides on Supercritical Steam, sCO2 Power Cycles – Indirect, sCO2 Power Cycles – Direct, Experimental Exposures, Alloys, Why Si, Results—Ni-xCr Alloys (5-24Cr), Fatigue Crack Growth$-$Experiment, and Alloys and Samples, Fatigue Crack Growth—Results (H282).

  11. Investigation of Relative Time Constant Influence of Inertial Part of Superheater on Quality of Steam Temperature Control Behind Boiler in Broad Band of Loading Variations

    Directory of Open Access Journals (Sweden)

    G. T. Kulakov

    2008-01-01

    Full Text Available The paper is devoted to computational investigation of influence relative time constant of an object which changes in broad band on quality of steam temperature control behind a boiler with due account of value of regulating action in the system with PI- and PID- regulator. The simulation has been based on a single-loop automatic control system (ACS. It has been revealed that the less value of the relative time constant of an object leads to more integral control error in system with PID- regulator while operating external ACS perturbation. Decrease of numerical value of relative time constant of an object while operating external perturbation causes decrease of relative time concerning appearance of maximum dynamic control error from common relative control time.

  12. 超临界二氧化碳萃取及水蒸气蒸馏法提取降香挥发油及其GC-MS分析%Analyze on Chemical Compositions of Dalbergia odorifera Essential Oils Extracted by CO2-Supercritical-Fluid-Extraction and Steam Distillation Extraction

    Institute of Scientific and Technical Information of China (English)

    宋伟峰; 廖美金; 罗淑媛

    2011-01-01

    目的:用超临界二氧化碳萃取及水蒸气蒸馏法提取降香挥发油,并对挥发油进行GC-MS分析.方法:采用超临界二氧化碳萃取法(SFE-CO2)及水蒸气蒸馏法提取降香挥发油,并应用气相色谱-质谱联用(GC-MS)技术分析挥发油的化学成分,用峰面积归一法测定各化合物的相对含量.结果:在超临界CO2提取物中共鉴定出12种化合物,占总峰面积的34.49%,含量最高的是橙花叔醇(14.95%)、2-丙烯酸3-(4-甲氧基)乙酯(14.53%)、胜红蓟色烯(1.33%).在水蒸气蒸馏法提取的降香挥发油中共鉴定出9种化合物,占总峰面积的30.62%,含量最高的是橙花叔醇(26.61%)、雪松醇(1.65%).结论:超临界法较水蒸气法更加稳定可靠、重现性好,适用于降香挥发油的提取.%Objective;To analyze the chemical compositions of Dalbergia odorifera essential oils extacted by CO2-supercritical-fluid-extraction (SFE-CO2)and steam distillation extraction (SD). Methods:The essential oils of Dalbergia odorifera were extracted by steam distillation extraction and SFE-CO2. The chemical components were separated and analyzed by gas chromatography-mass spec-trometry. Results: 12 compounds were identified in SFE sample. The major components from essential oils were 2-propenoic acid-3(4-methoxyphenyl)-ethyl ester( 14. 53% ), nerolidol( 14. 95% ), ageratochromene(1. 33% ). 9 compounds were identified in SD sample. The major components from essential oils were nerolidol(26. 61% ) ,cedrol( 1. 65% ). Conclusion:The SFE method is better than the SD method in reliability stability and reproducibility, and suitable for essential oils extraction of Dalbergia odorifera.

  13. Minimization of the negative influence on the biosphere in heavy oil extraction and ecologically clean technology for the injection of the steam with supercritical parameters in oil strata on the basis of new ecologically clean tubing pipes with heat-resistant coatings

    Science.gov (United States)

    Komkov, M. A.; Moiseev, V. A.; Tarasov, V. A.; Timofeev, M. P.

    2015-12-01

    Some ecological problems related to heavy-oil extraction and ways for minimizing the negative impacts of this process on the biosphere are discussed. The ecological hazard of, for example, frequently used multistage hydraulic fracturing of formation is noted and the advantages and perspectives of superheated steam injection are considered. Steam generators of a new type and ecologically clean and costeffective insulating for tubing pipes (TPs) are necessary to develop the superheated steam injection method. The article is devoted to solving one of the most important and urgent tasks, i.e., the development and usage of lightweight, nonflammable, environmentally safe, and cost-effective insulating materials. It is shown that, for tubing shielding operating at temperatures up to 420°C, the most effective thermal insulation is a highly porous material based on basalt fiber. The process of filtration deposition of short basalt fibers with a bunch of alumina thermal insulation tubing pipe coatings in the form of cylinders and cylindrical shells from liquid pulp is substantiated. Based on the thermophysical characteristics of basalt fibers and on the technological features of manufacturing highly porous coating insulation, the thickness of a tubing pipe is determined. During the prolonged pumping of the air at an operating temperature of 400°C in the model sample of tubing pipes with insulation and a protective layer, we find that the surface temperature of the thermal barrier coating does not exceed 60°C. Introducing the described technology will considerably reduce the negative impact of heavy-oil extraction on the biosphere.

  14. Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

    Science.gov (United States)

    Balicki, Adrian; Bartela, Łukasz

    2014-06-01

    Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of `zeroemission' technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes.

  15. Fixation of compressive deformation in wood by pre-steaming

    Science.gov (United States)

    M. Inoue; N. Sekino; T. Morooka; R.M. Rowell; M. Norimoto

    2008-01-01

    Wood block specimens pre-steamed at 120-220 °C for 5-20 min were compressed in the radial direction. The recovery of set decreased with increasing pre-steaming temperature and time. The reduction of set recovery correlated with the amount of weight loss in steaming irrespective of pre-steaming temperature and time. The weight loss for the highest level of...

  16. Steam Drum Design for Direct Steam Generation

    OpenAIRE

    Willwerth, Lisa; Müller, Svenja; Krüger, Joachim; Succo, Manuel; Feldhoff, Jan Fabian; Tiedemann, Jörg; Pandian, Juvaraj; Krüger, Dirk; Hennecke, Klaus

    2016-01-01

    For the direct steam generation in solar fields, the recirculation concept has been demonstrated in several installations. Water masses in the solar field vary during transient phases, such as passing clouds. The volume of the steam drum can serve as a buffer during such transients by taking in excess water and providing water storage. The saturated steam mass flow to the superheating section or the consumer can be maintained almost constant during short transients; therefore the steam drum p...

  17. Engineering Design for High-temperature Steam Treatment Process of Medical Waste%医疗废物高温蒸汽处理工艺工程设计探讨

    Institute of Scientific and Technical Information of China (English)

    靳俊平; 勾冬梅; 高波; 曲伟国

    2013-01-01

    介绍了医疗废物高温蒸汽处理工艺的特点,并针对此类工程设计提出了建议.%The characteristics of high-temperature steam treatment process for medical waste were introduced. And some suggestions for its engineering design were put forward.

  18. Liquid metal reactor KALIMER development - Study on the high temperature properties of the steam generator tubing for LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yong Soo; Kim, Soon Tae; Park, Hui Sang; Kim, Soo Han [Yonsei University, Seoul (Korea); Kim, Young Sik [Andong National University, Andong (Korea)

    1999-04-01

    This work dealt with the evaluation of super stainless steels for steam generator tubing of LMFBR. The experimental alloys were designed to simulate the elimination of alloying elements, in special, C and N. Regardless of carbon contents, super stainless steels showed the excellent properties (tensile properties and corrosion resistance) than those of 9Cr-1Mo steel. Nitrogen content has affected positively the ultimate tensile strength and yield strength by TT(Thermal Treatment), but the elongation was reduced by TT in case of nitrogen free alloy and the elongation was largely increased by TT in case of nitrogen bearing alloys. In acidic chloride environment, nitrogen has influenced a little on corrosion potential and critical current density, but largely on passive current density, especially, at high potential. However, the trend of corrosion potential and critical current density by nitrogen was similar to the results in acidic solutions, but passive current density was largely affected by nitrogen content of stainless steels. 29 refs., 24 figs., 8 tabs. (Author)

  19. Study on the Effect of Water-feed Flow of DC Boiler on the Steam-water Interface and Steam Temperature%直流锅炉给水流量对汽水分界面及蒸汽温度影响的研究

    Institute of Scientific and Technical Information of China (English)

    邢蕾; 马彦喜

    2016-01-01

    With the development of modern thermal power, the temperature, pressure and other parameters of the unit continue to improve, the unit capacity is increasing. DC boiler has become the main model of boiler development in the future thermal power plant. It can save investment, reduce coal consumption for power generation, and has the advantages of energy saving and emission reduction and so on. Through a lot of experiments, this paper analyzes the effect of water-feed flow of DC boiler on the steam-water interface and steam temperature and the relationship between the two, sums up the effects of the changes of steam-water interface and steam temperature on the material of the heating surface and steam quality of the boiler to provide theoretical basis for the safe operation of the DC boiler.%随着现代火力发电的发展,机组温度、压力等各项参数不断提高,机组容量日趋增大。直流锅炉已成为未来火力发电厂锅炉发展的主要机型。其具有节省投资、降低发电煤耗、节能减排等诸多优点。本文通过大量的实验,分析直流锅炉给水流量对汽水界面及蒸汽温度的影响和两者之间的关系;归纳汽水界面及蒸汽温度的变化对锅炉各受热面材料和蒸汽质量的影响。为直流锅炉的安全运行提供理论依据。

  20. DNS of High Pressure Supercritical Combustion

    Science.gov (United States)

    Chong, Shao Teng; Raman, Venkatramanan

    2016-11-01

    Supercritical flows have always been important to rocket motors, and more recently to aircraft engines and stationary gas turbines. The purpose of the present study is to understand effects of differential diffusion on reacting scalars using supercritical isotropic turbulence. Focus is on fuel and oxidant reacting in the transcritical region where density, heat capacity and transport properties are highly sensitive to variations in temperature and pressure. Reynolds and Damkohler number vary as a result and although it is common to neglect differential diffusion effects if Re is sufficiently large, this large variation in temperature with heat release can accentuate molecular transport differences. Direct numerical simulations (DNS) for one step chemistry reaction between fuel and oxidizer are used to examine the differential diffusion effects. A key issue investigated in this paper is if the flamelet progress variable approach, where the Lewis number is usually assumed to be unity and constant for all species, can be accurately applied to simulate supercritical combustion.

  1. Effect of Economizer Heat Transfer Design and Retrofitting on Superheated Steam Temperature for the Utility Boiler%电站锅炉省煤器设计与改造对过热汽温的影响

    Institute of Scientific and Technical Information of China (English)

    阎维平

    2001-01-01

    According to internal relations between steam production of the evaporator and superheater steam temperature, indirect effect of economizer exit water temperature variation on superheated steam temperature at boiler exit are discussed based on heat and mass balance. It is proposed that in the designing or retrofitting of economizer, if heat transfer surface have to be changed it is necessary to implement the thermal calculation in both flue gas side and water/steam side. The calculation emphasizes on the effect of water temperature variation at economizer exit of evaporator working condition and superheated steam temperature.%根据锅炉蒸发受热面工质侧产汽量与过热汽温之间的内在依赖关系,从热量和质量平衡原理出发,讨论了自然循环锅炉给水温度不变而省煤器出口水温偏离设计值时对过热汽温间接的影响规律。在电站锅炉尾部受热面的改造或设计中,为考虑其它因素而不得不改变省煤器的吸热量时,建议将锅炉烟气侧热力计算与工质侧的吸热产汽量计算结合起来,验算省煤器出口水温的变化对炉膛蒸发受热面工作以及过热汽温的影响。

  2. Characteristics of compressible flow of supercritical kerosene

    Institute of Scientific and Technical Information of China (English)

    Feng-Quan Zhong; Xue-Jun Fan; Jing Wang; Gong Yu; Jian-Guo Li

    2012-01-01

    In this paper,compressible flow of aviation kerosene at supercritical conditions has been studied both numerically and experimentally.The thermophysical properties of supercritical kerosene are calculated using a 10-species surrogate based on the principle of extended corresponding states (ECS).Isentropic acceleration of supercritical kerosene to subsonic and supersonic speeds has been analyzed numerically.It has been found that the isentropic relationships of supercritical kerosene are significantly different from those of ideal gases.A two-stage fuel heating and delivery system is used to heat the kerosene up to a temperature of 820 K and pressure of 5.5 MPa with a maximum mass flow rate of 100 g/s.The characteristics of supercritical kerosene flows in a converging-diverging nozzle (Laval nozzle) have been studied experimentally.The results show that stable supersonic flows of kerosene could be established in the temperature range of 730 K-820 K and the measurements in the wall pressure agree with the numerical calculation.

  3. Laboratory experiments of high-temperature steam and nitrogen foam compound flooding%高温蒸汽氮气泡沫复合驱实验研究

    Institute of Scientific and Technical Information of China (English)

    孙焕泉; 王敬; 刘慧卿; 杨耀忠; 彭国红; 赖书敏

    2011-01-01

    为了研究不同因素对泡沫封堵特性和高温蒸汽氮气驱提高采收率效果的影响,开展了发泡剂浓度、温度、气液比、渗透率和含油饱和度对3种发泡剂生成泡沫封堵能力影响规律、发泡剂浓度和蒸汽氮气混注比对蒸汽泡沫复合体系封堵特性影响以及不同发泡剂单管和双管驱油实验.研究结果表明,泡沫阻力因子随发泡剂浓度、气液比、渗透率增加而增大,后期增加速度较缓,最佳质量分数和气液比为0.5%和1∶1;阻力因子随含油饱和度增加而减小,含油饱和度大于0.2时,泡沫基本失去封堵能力;1#、2#发泡剂生成泡沫的阻力因子随温度增加而降低,3#随温度增加而升高;蒸汽氮气泡沫混注时,最佳质量分数和蒸汽氮气混注比为0.6%和3:2;注2#和3#发泡剂的蒸汽氮气泡沫复合驱提高采收率20.82%和17.05%;2#发泡剂提高波及系数和洗油效率为13%和24.6%,3#发泡剂提高波及系数和洗油效率为9.05%和21.9%,2#发泡剂性能优于3#发泡剂.%In order to study the influences of different factors on plugging property of foams and oil recovery enhance effect of high-temperature steam and nitrogen flooding, the effects of foaming agents concentration, temperature, gas-liquid ratio, permeability and oil saturation on the plugging ability of 3 foaming agents, the effects of foaming agent concentration and the ratio of steam and nitrogen on the plugging poverty of steam - nitrogen foam compound flooding system and the flooding tests of various foaming agents in single pipe and dual-pipe were all studied by experiments. The results indicated that the foam resistance factor increased with the increase of the concentration, gas-liquid ratio and permeability and the trend slowed down in the later period of experiments. The optimal concentration was 0.5% and the optimum gas-liquid ratio was 1:1. On the other hand, the resistance factor reduced with the oil

  4. An installation for steam conversion of gases

    Energy Technology Data Exchange (ETDEWEB)

    Tabata, K.; Matsumoto, I.

    1983-01-28

    An installation is proposed for steam conversion of a hydrocarbon gas in order to produce an inorganic gas which chiefly consists of H2 and CO in which the line for feeding the hydrocarbon gas has a steam generator which has a microcapillary structure made of sponge metal, inorganic heat resistant fibers of glass, Si02, Al203 or carbon, inorganic heat resistant fibers twisted into a fiber or a cord of multipore ceramic material; the installation is equipped with a heater which regulates the water temperature, in which the steam generator is submerged. The installation is designed for converting natural gas, C3H8, other hydrocarbon gases and vapors of liquid hydrocarbons (Uv) into H2 and CO. The design and disposition of the steam generator simplify the design of the device, eliminating the pump for feeding the steam and the device for premixing of the steam and hydrocarbon gas.

  5. Steam generated conversion coating on aluminium alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    pressure steam produced by an autoclave at a temperature of 107 – 121 °C and pressure of 15 -17 psi for 10 minutes to produce a thin coating of aluminium oxide. The aim of this study is to understand the effect of high pressure steam with and without different chemical additives on surface morphology...

  6. Detection and evaluation of corrosion zones at high temperature in steam generators; Deteccion y evaluacion de zonas de corrosion en alta temperatura de generadoras de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Villafane, Alberto; Chacon Nava, Jose G.; Huerta Espino, Mario; Mojica Calderon, Cecilio; Castillo Viveros, Antonio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1990-12-31

    This paper presents the methodology for the detection and evaluation of high corrosion zones at high temperature. The results found up to now, show a critical zone in the Babcock Hitachi design, specifically in the high temperature reheater in the zone nearby the outlet header. In the normalized design CE (Mitsubishi) of 300 MW and CE (Canada) of 300 MW, the results found in recent years show small thickness reduction, therefore a good operation of these steam generators is recognized. [Espanol] En este trabajo se presenta la metodologia para la deteccion y evaluacion de zonas de corrosion en alta temperatura. Los resultados encontrados hasta el momento muestran una zona critica en el diseno Babcock Hitachi, especificamente en el recalentador de alta temperatura en la zona cercana al cabezal de salida. En el diseno normalizado CE (Mitsubishi) de 300 MW y CE (Canada) de 300 MW, los resultados encontrados en anos recientes muestran poca disminucion de espesor, por lo que se considera una buena operacion de estos generadores de vapor.

  7. Optimizing steam flood performance utilizing a new and highly accurate two phase steam measurement system

    Energy Technology Data Exchange (ETDEWEB)

    Huff, B. D.; Warren, P. B. [CalResources LLC (Canada); Whorff, F. [ITT Barton (Canada)

    1995-11-01

    The development of a two phase steam measurement system was documented. The system consists of a `V` cone differential pressure device and a vortex meter velocity device in series through which the steam flows. Temperature and pressure sensors are electronically interfaced with a data logging system. The design was described as being very simple and rugged, consequently, well suited to monitoring in the field.. Steam quality measurements were made in the Kern River Field and the Coalinga Field thermal projects using a surface steam separator. In steam flood operations, steam cost is very high, hence appropriate distribution of the steam can result in significant cost reduction. This technology allows the measurement of steam flow and quality at any point in the steam distribution system. The metering system`s orifice meter was found to have a total average error of 45%, with 25% of that attributable to `cold leg` problem. Installation of the metering system was expected to result in a steam use reduction of 8%, without any impact on production. Steam re-distribution could result in a potential oil production increase of 10%. 12 refs., 8 tabs., 9 figs.

  8. Advanced Supercritical Carbon Dioxide Brayton Cycle Development

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark [Univ. of Wisconsin, Madison, WI (United States); Sienicki, James [Argonne National Lab. (ANL), Argonne, IL (United States); Moisseytsev, Anton [Argonne National Lab. (ANL), Argonne, IL (United States); Nellis, Gregory [Univ. of Wisconsin, Madison, WI (United States); Klein, Sanford [Univ. of Wisconsin, Madison, WI (United States)

    2015-10-21

    Fluids operating in the supercritical state have promising characteristics for future high efficiency power cycles. In order to develop power cycles using supercritical fluids, it is necessary to understand the flow characteristics of fluids under both supercritical and two-phase conditions. In this study, a Computational Fluid Dynamic (CFD) methodology was developed for supercritical fluids flowing through complex geometries. A real fluid property module was implemented to provide properties for different supercritical fluids. However, in each simulation case, there is only one species of fluid. As a result, the fluid property module provides properties for either supercritical CO2 (S-CO2) or supercritical water (SCW). The Homogeneous Equilibrium Model (HEM) was employed to model the two-phase flow. HEM assumes two phases have same velocity, pressure, and temperature, making it only applicable for the dilute dispersed two-phase flow situation. Three example geometries, including orifices, labyrinth seals, and valves, were used to validate this methodology with experimental data. For the first geometry, S-CO2 and SCW flowing through orifices were simulated and compared with experimental data. The maximum difference between the mass flow rate predictions and experimental measurements is less than 5%. This is a significant improvement as previous works can only guarantee 10% error. In this research, several efforts were made to help this improvement. First, an accurate real fluid module was used to provide properties. Second, the upstream condition was determined by pressure and density, which determines supercritical states more precise than using pressure and temperature. For the second geometry, the flow through labyrinth seals was studied. After a successful validation, parametric studies were performed to study geometric effects on the leakage rate. Based on these parametric studies, an optimum design strategy for the see

  9. Electrochemistry in supercritical fluids

    Science.gov (United States)

    Branch, Jack A.; Bartlett, Philip N.

    2015-01-01

    A wide range of supercritical fluids (SCFs) have been studied as solvents for electrochemistry with carbon dioxide and hydrofluorocarbons (HFCs) being the most extensively studied. Recent advances have shown that it is possible to get well-resolved voltammetry in SCFs by suitable choice of the conditions and the electrolyte. In this review, we discuss the voltammetry obtained in these systems, studies of the double-layer capacitance, work on the electrodeposition of metals into high aspect ratio nanopores and the use of metallocenes as redox probes and standards in both supercritical carbon dioxide–acetonitrile and supercritical HFCs. PMID:26574527

  10. Electrochemistry in supercritical fluids.

    Science.gov (United States)

    Branch, Jack A; Bartlett, Philip N

    2015-12-28

    A wide range of supercritical fluids (SCFs) have been studied as solvents for electrochemistry with carbon dioxide and hydrofluorocarbons (HFCs) being the most extensively studied. Recent advances have shown that it is possible to get well-resolved voltammetry in SCFs by suitable choice of the conditions and the electrolyte. In this review, we discuss the voltammetry obtained in these systems, studies of the double-layer capacitance, work on the electrodeposition of metals into high aspect ratio nanopores and the use of metallocenes as redox probes and standards in both supercritical carbon dioxide-acetonitrile and supercritical HFCs.

  11. Supercritical Fluid Extraction of Aflatoxin B 1 from Soil

    Science.gov (United States)

    This research describes the development of a Supercritical Fluid Extraction (SFE) method to recover aflatoxin B1 from fortified soil. The effects of temperature, pressure, modifier (identity and percentage), and extraction type were assessed. Using the optimized SFE conditions, ...

  12. Supercritical Fluid Extraction of Aflatoxin B 1 from Soil

    Science.gov (United States)

    This research describes the development of a Supercritical Fluid Extraction (SFE) method to recover aflatoxin B1 from fortified soil. The effects of temperature, pressure, modifier (identity and percentage), and extraction type were assessed. Using the optimized SFE conditions, ...

  13. Supercritical Water Reactor (SCWR) - Survey of Materials Research and Development Needs to Assess Viability

    Energy Technology Data Exchange (ETDEWEB)

    Philip E. MacDonald

    2003-09-01

    Supercritical water-cooled reactors (SCWRs) are among the most promising advanced nuclear systems because of their high thermal efficiency [i.e., about 45% vs. 33% of current light water reactors (LWRs)] and considerable plant simplification. SCWRs achieve this with superior thermodynamic conditions (i.e., high operating pressure and temperature), and by reducing the containment volume and eliminating the need for recirculation and jet pumps, pressurizer, steam generators, steam separators and dryers. The reference SCWR design in the U.S. is a direct cycle, thermal spectrum, light-water-cooled and moderated reactor with an operating pressure of 25 MPa and inlet/outlet coolant temperature of 280/500 °C. The inlet flow splits, partly to a down-comer and partly to a plenum at the top of the reactor pressure vessel to flow downward through the core in special water rods to the inlet plenum. This strategy is employed to provide good moderation at the top of the core, where the coolant density is only about 15-20% that of liquid water. The SCWR uses a power conversion cycle similar to that used in supercritical fossil-fired plants: high- intermediate- and low-pressure turbines are employed with one moisture-separator re-heater and up to eight feedwater heaters. The reference power is 3575 MWt, the net electric power is 1600 MWe and the thermal efficiency is 44.8%. The fuel is low-enriched uranium oxide fuel and the plant is designed primarily for base load operation. The purpose of this report is to survey existing materials for fossil, fission and fusion applications and identify the materials research and development needed to establish the SCWR viabilitya with regard to possible materials of construction. The two most significant materials related factors in going from the current LWR designs to the SCWR are the increase in outlet coolant temperature from 300 to 500 °C and the possible compatibility issues associated with the supercritical water environment.

  14. Adsorption from Experimental Isotherms of Supercritical Gases

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A mathematical method was proposed for the determination of absolute adsorption from experimental isotherms. The method is based on the numerical equality of the absolute and the excess adsorption when either the gas phase density or the amount adsorbed is not quite considerable. The initial part of the experimental isotherms, which represents the absolute adsorption, became linear with some mathematical manipulations. The linear isotherms were reliably formulated. As consequence, either the volume or the density of the supercritical adsorbate could be determined by a non-empirical way. This method was illustrated by the adsorption data of supercritical hydrogen and methane on a superactivated carbon in large ranges of temperature and pressure.

  15. Supercritical-Multiple-Solvent Extraction From Coal

    Science.gov (United States)

    Corcoran, W.; Fong, W.; Pichaichanarong, P.; Chan, P.; Lawson, D.

    1983-01-01

    Large and small molecules dissolve different constituents. Experimental apparatus used to test supercritical extraction of hydrogen rich compounds from coal in various organic solvents. In decreasing order of importance, relevant process parameters were found to be temperature, solvent type, pressure, and residence time.

  16. Effect of supercritical fluid density on nanoencapsulated drug particle size using the supercritical antisolvent method.

    Science.gov (United States)

    Kalani, Mahshid; Yunus, Robiah

    2012-01-01

    The reported work demonstrates and discusses the effect of supercritical fluid density (pressure and temperature of supercritical fluid carbon dioxide) on particle size and distribution using the supercritical antisolvent (SAS) method in the purpose of drug encapsulation. In this study, paracetamol was encapsulated inside L-polylactic acid, a semicrystalline polymer, with different process parameters, including pressure and temperature, using the SAS process. The morphology and particle size of the prepared nanoparticles were determined by scanning electron microscopy and transmission electron microscopy. The results revealed that increasing temperature enhanced mean particle size due to the plasticizing effect. Furthermore, increasing pressure enhanced molecular interaction and solubility; thus, particle size was reduced. Transmission electron microscopy images defined the internal structure of nanoparticles. Thermal characteristics of nanoparticles were also investigated via differential scanning calorimetry. Furthermore, X-ray diffraction pattern revealed the changes in crystallinity structure during the SAS process. In vitro drug release analysis determined the sustained release of paracetamol in over 4 weeks.

  17. Metal Nanoparticles Preparation In Supercritical Carbon Dioxide Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Harry W. Rollins

    2004-04-01

    The novel optical, electronic, and/or magnetic properties of metal and semiconductor nanoparticles have resulted in extensive research on new methods for their preparation. An ideal preparation method would allow the particle size, size distribution, crystallinity, and particle shape to be easily controlled, and would be applicable to a wide variety of material systems. Numerous preparation methods have been reported, each with its inherent advantages and disadvantages; however, an ideal method has yet to emerge. The most widely applied methods for nanoparticle preparation include the sonochemical reduction of organometallic reagents,(1&2) the solvothermal method of Alivisatos,(3) reactions in microemulsions,(4-6) the polyol method (reduction by alcohols),(7-9) and the use of polymer and solgel materials as hosts.(10-13) In addition to these methods, there are a variety of methods that take advantage of the unique properties of a supercritical fluid.(14&15) Through simple variations of temperature and pressure, the properties of a supercritical fluid can be continuously tuned from gas-like to liquid-like without undergoing a phase change. Nanoparticle preparation methods that utilize supercritical fluids are briefly reviewed below using the following categories: Rapid Expansion of Supercritical Solutions (RESS), Reactive Supercritical Fluid Processing, and Supercritical Fluid Microemulsions. Because of its easily accessible critical temperature and pressure and environmentally benign nature, carbon dioxide is the most widely used supercritical solvent. Supercritical CO2 is unfortunately a poor solvent for many polar or ionic species, which has impeded its use in the preparation of metal and semiconductor nanoparticles. We have developed a reactive supercritical fluid processing method using supercritical carbon dioxide for the preparation of metal and metal sulfide particles and used it to prepare narrowly distributed nanoparticles of silver (Ag) and silver sulfide

  18. Supercritical fluid thermodynamics for coal processing

    Energy Technology Data Exchange (ETDEWEB)

    van Swol, F. (Illinois Univ., Urbana, IL (United States). Dept. of Chemical Engineering); Eckert, C.A. (Georgia Inst. of Tech., Atlanta, GA (United States). School of Chemical Engineering)

    1988-09-15

    The main objective of this research is to develop an equation of state that can be used to predict solubilities and tailor supercritical fluid solvents for the extraction and processing of coal. To meet this objective we have implemented a two-sided. approach. First, we expanded the database of model coal compound solubilities in higher temperature fluids, polar fluids, and fluid mixtures systems. Second, the unique solute/solute, solute/cosolvent and solute/solvent intermolecular interactions in supercritical fluid solutions were investigated using spectroscopic techniques. These results increased our understanding of the molecular phenomena that affect solubility in supercritical fluids and were significant in the development of an equation of state that accurately reflects the true molecular makeup of the solution. (VC)

  19. Heat Transfer Phenomena of Supercritical Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Krau, Carmen Isabella; Kuhn, Dietmar; Schulenberg, Thomas [Forschungszentrum Karlsruhe, Institute for Nuclear and Energy Technologies, 76021 Karlsruhe (Germany)

    2008-07-01

    In concepts for supercritical water cooled reactors, the reactor core is cooled and moderated by water at supercritical pressures. The significant temperature dependence of the fluid properties of water requires an exact knowledge of the heat transfer mechanism to avoid fuel pin damages. Near the pseudo-critical point a deterioration of heat transfer might happen. Processes, that take place in this case, are not fully understood and are due to be examined systematically. In this paper a general overview on the properties of supercritical water is given, experimental observations of different authors will be reviewed in order to identify heat transfer phenomena and onset of occurrence. The conceptional design of a test rig to investigate heat transfer in the boundary layer will be discussed. Both, water and carbon dioxide, may serve as operating fluids. The loop, including instrumentation and safety devices, is shown and suitable measuring methods are described. (authors)

  20. Supercritical Airfoil Coordinates

    Data.gov (United States)

    National Aeronautics and Space Administration — Rectangular Supercritical Wing (Ricketts) - design and measured locations are provided in an Excel file RSW_airfoil_coordinates_ricketts.xls . One sheet is with Non...

  1. 超临界氨合成%AMMONIA SYNTHESIS AT SUPERCRITICAL CONDITIONS

    Institute of Scientific and Technical Information of China (English)

    刘化章; 唐浩东; 李小年

    2004-01-01

    Ammonia synthesis at supercritical conditions was first studied over iron and active carbonsupported ruthenium catalysts in a fixed-bed reactor. The influences of 15 kinds of different supercritical media, such as alkanes of C7-C13, 1, 2, 3, 4-tetrahydronaphthalene, cis-decalin, o-xylene,ethylbenzene, quinolin, n-hexane and aniline etc. and reaction conditions (catalyst, temperature, space velocity, particial pressure of media) on ammonia at supercritical condition were investigated.Supercritical medium was decomposed under reaction conditions over Fe and Ru/AC catalysts. The decomposition products deactivated the catalysts. Alkane decomposed the least, and the rate of deactivation was the slowest. Therefore alklane was a relatively good medium. The decomposion of supercritical medium was the key for the deactivation of catalysts. Another important reason for the decrease of ammonia concentration was that the effective pressure of syngas decreased because of the presence of supercritical media. The active temperature of catalyst was the decisive factor in supercritical ammonia synthesis. Supercritical catalytic reaction was viable only at a lower temperature. Ammonia ynthesis at supercritical conditions is possible if a catalyst with active temperature lower than 573 K could e developed and the decomposition of supercritical media could be prevented.

  2. Supercritical Fluid Chromatography, Pressurized Liquid Extraction and Supercritical Fluid Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Henry, Matthew C.; Yonker, Clement R.

    2006-06-15

    In this review we examine the related fields of supercritical fluid chromatography (SFC) and supercritical fluid extraction (SFE). We reviewed the published literature in the period from November 2003 to November 2005. Well over 300 papers were published in this period. This large body of work indicates continuing active growth of the field, but an exhaustive review is beyond the scope of this work. We have chosen to include a sampling of publications that best represent the continuing trends and new ideas in the field. In keeping with past reviews on this subject1, we have broadened our scope to include fluid systems operating at high temperature and pressure, but below the critical point. Various terms have been applied to this state: sub-critical fluid extraction, pressurized liquid extraction, and accelerated solvent extraction. The term accelerated solvent extraction has been used by instrument manufacturers to refer to this process, but we will use the more descriptive term pressurized liquid extraction (PLE) to refer to these systems. Most of the research in the field is of an “evolutionary” rather than “revolutionary” nature. As in the previous review period, applications papers make up a majority of the published work. Pharmaceutical applications continue to be a strong theme. Most of the pharmaceutical work has centered on preparative, rather than analytical, separations. Chiral separations are an exception, as analytical scale separations of chiral compounds are an area of intense interest. Food and natural products represent the next largest body of work. Major themes are the isolation and characterization of high-value added foodstuffs, fragrances, and flavor compounds from novel natural materials or agricultural by-products. The areas of food, natural products, and pharmaceutical separation science converge in the area of so-called nutraceuticals. These are typically high-value products, either sold alone or as part of a fortified food, that

  3. Tension-Compression Fatigue of an Oxide/Oxide Ceramic Matrix Composite at Elevated Temperature in Air and Steam Environments

    Science.gov (United States)

    2015-03-26

    than several other advanced aerospace materials [15]. It is these qualities that make ceramics candidate materials for advanced aerospace ...TENSION-COMPRESSION FATIGUE OF AN OXIDE/OXIDE CERAMIC MATRIX COMPOSITE AT ELEVATED TEMPERATURE IN...is not subject to copyright protection in the United States. AFIT-ENY-MS-15-M-222 TENSION-COMPRESSION FATIGUE OF AN OXIDE/OXIDE CERAMIC MATRIX

  4. Analysis of experimental characteristics of multistage steam-jet electors of steam turbines

    Science.gov (United States)

    Aronson, K. E.; Ryabchikov, A. Yu.; Brodov, Yu. M.; Brezgin, D. V.; Zhelonkin, N. V.; Murmanskii, I. B.

    2017-02-01

    A series of questions for specification of physical gas dynamics model in flow range of steam-jet unit and ejector computation methodology, as well as functioning peculiarities of intercoolers, was formulated based on analysis of experimental characteristics of multistage team-jet steam turbines. It was established that coefficient defining position of critical cross-section of injected flow depends on characteristics of the "sound tube" zone. Speed of injected flow within this tube may exceed that of sound, and pressure jumps in work-steam decrease at the same time. Characteristics of the "sound tube" define optimal axial sizes of the ejector. According to measurement results, the part of steam condensing in the first-stage coolant constitutes 70-80% of steam amount supplied into coolant and is almost independent of air content in steam. Coolant efficiency depends on steam pressure defined by operation of steam-jet unit of ejector of the next stage after coolant of steam-jet stage, temperature, and condensing water flow. As a rule, steam entering content of steam-air mixture supplied to coolant is overheated with respect to saturation temperature of steam in the mixture. This should be taken into account during coolant computation. Long-term operation causes changes in roughness of walls of the ejector's mixing chamber. The influence of change of wall roughness on ejector characteristic is similar to the influence of reverse pressure of the steam-jet stage. Until some roughness value, injection coefficient of the ejector stage operating in superlimiting regime hardly changed. After reaching critical roughness, the ejector switches to prelimiting operating regime.

  5. Study on mathematical model of steam coal blending

    Institute of Scientific and Technical Information of China (English)

    高洪阁; 李白英; 刘泽常; 尹增德

    2002-01-01

    It is necessary to set up a new mathematical model of steam coal blending instead of the old model. Indexes such as moisture content, ash content, volatile matter, sulfur content and heating value in the new mathematical model have linear relation. The new mathematical model can also predict ash-fusion temperature precisely by considering coal ash ratio in steam coal blending, therefore it is possible to obtain linear relation of ash-fusion temperature between single coal and steam coal blending. The new mathematical model can improve precision of steam coal blending and perfect the old mathematical model of steam coal blending.

  6. How to compute the power of a steam turbine with condensation, knowing the steam quality of saturated steam in the turbine discharge

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Albarran, Manuel Jaime; Krever, Marcos Paulo Souza [Braskem, Sao Paulo, SP (Brazil)

    2009-07-01

    To compute the power and the thermodynamic performance in a steam turbine with condensation, it is necessary to know the quality of the steam in the turbine discharge and, information of process variables that permit to identifying with high precision the enthalpy of saturated steam. This paper proposes to install an operational device that will expand the steam from high pressure point on the shell turbine to atmosphere, both points with measures of pressure and temperature. Arranging these values on the Mollier chart, it can be know the steam quality value and with this data one can compute the enthalpy value of saturated steam. With the support of this small instrument and using the ASME correlations to determine the equilibrium temperature and knowing the discharge pressure in the inlet of surface condenser, the absolute enthalpy of the steam discharge can be computed with high precision and used to determine the power and thermodynamic efficiency of the turbine. (author)

  7. The role of metal-support interaction for CO-free hydrogen from low temperature ethanol steam reforming on Rh-Fe catalysts.

    Science.gov (United States)

    Choong, Catherine K S; Chen, Luwei; Du, Yonghua; Schreyer, Martin; Daniel Ong, S W; Poh, Chee Kok; Hong, Liang; Borgna, Armando

    2017-02-08

    Rh-Fe catalysts supported on Ca-Al2O3, MgO and ZrO2 were evaluated in ethanol steam reforming at 623 K and compared to Rh catalysts on the same supports without iron promotion. The metal-support interaction among the three entities, i.e. Rh ↔ Fe2O3 ← support (ZrO2, MgO and Ca-Al2O3) was investigated using H2-chemisorption, TEM, XPS and in situ techniques such as DRIFTS, temperature-resolved XRD and XAS. As compared to the unpromoted Rh catalysts on the same supports, the CO selectivity is depressed in the presence of iron on Rh/MgO and Rh/Ca-Al2O3, the latter being significantly superior. The role of metal-support interaction for CO-free hydrogen generation was unravelled using a combination of techniques. It was found that the reducibility of iron oxide determines the extent of the strong metal support interaction between Rh and Fe2O3 and the reducibility of iron oxide was affected by the support. On Rh-Fe/Ca-Al2O3, a good balance of the interaction between Rh, Fe2O3 and Ca-Al2O3 prevents strong metal support interaction between Rh and Fe2O3 and thus promotes CO elimination via water-gas-shift reaction on Rh-FexOy sites.

  8. Effect of seed source and pelleting temperature during steam pelleting on apparent metabolizable energy value of full-fat canola seed for broiler chickens.

    Science.gov (United States)

    Toghyani, M; Swick, R A; Barekatain, R

    2016-10-28

    Eleven canola seed (CS) samples were collected from different commercial feedmills and crushing plants in Australia and analyzed for nutrient profile. Six of these samples were selected to determine the effect of seed chemical composition and pellet temperature (PT) during steam pelleting on apparent metabolizable energy corrected for nitrogen (AMEn) values of CS for broiler chickens using a 6 × 2 factorial arrangement of treatments. The CS samples were incorporated into a corn-soybean meal diet at 15% by replacing energy-yielding ingredients, and diets were steam pelleted at either 75 or 90°C. A total of 420 18-day-old male broiler chicks (Ross 308) was assigned to 14 experimental diets replicated 6 times, with 5 chicks per cage. After a 5-day diet acclimation period from d 18 to 22, excreta were collected for 72 h using the substitution method to determine AME and AMEn. There was no interaction of seed source and PT for ileal digestible energy (IDE), AME, or AMEn values of CS (P > 0.05). PT did not affect energy availability of CS (P > 0.05) but increasing the PT improved the pellet durability index of the diets by approximately 5.0 percentage points. A significant effect of seed source was detected for all the energy utilization values of CS (P < 0.05). The IDE, AME, and AMEn values of seed samples ranged from 5,239 to 5,645, 4,728 to 5,071, and 4,501 to 4,791 kcal/kg of DM, respectively. The mean AMEn values were 4,664 kcal/kg of DM, indicating a 5.7% reduction compared with AME values. There was a negative correlation between protein and fat content of the seeds (r = -0.93, P = 0.001), and, consequently, AMEn (r = -0.32, P = 0.009). AMEn values were positively correlated with fat content of CS (r = 0.649, P = 0.001). These results indicate that fat and protein content and fiber components may have a considerable effect on energy availability of CS for broiler chickens.

  9. Temperature control of a steam generator by means of an hybrid system PID-RLC; Control de las temperaturas de un generador de vapor mediante un sistema hibrido PID-RLC

    Energy Technology Data Exchange (ETDEWEB)

    Palomares Gonzalez, Daniel; Garcia Mendoza, Raul [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1990-12-31

    A description is made of the design and evaluation of an hybrid control system, formed by a quadratic gaussian linear regulator (QLR) and proportional integral derivative (PID) type regulators. This scheme is used to control the reheater and secondary superheater steam temperatures of a steam generator model with a maximum capacity of 2,150,000 pounds per hour. Once applied to the model of a 300 MW steam power plant, this system showed better results than the traditional schemes and inclusively better than some modern control schemes. This fact characterizes it as a high potential system to be applied to steam power plants. [Espanol] Se describe el diseno y la evaluacion de un sistema de control hibrido, formado por un regulador lineal cuadratico gaussiano (RLC) y reguladores tipo proporcional integral derivativo (PID). Este esquema se utiliza para controlar las temperaturas de vapor del recalentador y sobrecalentador secundario del modelo de un generador de vapor con capacidad maxima de 2,150,000 libras por hora. Una vez aplicado al modelo de una unidad termoelectrica de 300 MW, este sistema produjo mejores resultados que los esquemas tradicionales e incluso mejores que algunos esquemas de control moderno. Esto lo caracteriza como un sistema con un alto potencial para aplicarse a unidades termoelectricas.

  10. Techno-economic performance evaluation of direct steam generation solar tower plants with thermal energy storage systems based on high-temperature concrete and encapsulated phase change materials

    Science.gov (United States)

    Guédez, R.; Arnaudo, M.; Topel, M.; Zanino, R.; Hassar, Z.; Laumert, B.

    2016-05-01

    Nowadays, direct steam generation concentrated solar tower plants suffer from the absence of a cost-effective thermal energy storage integration. In this study, the prefeasibility of a combined sensible and latent thermal energy storage configuration has been performed from thermodynamic and economic standpoints as a potential storage option. The main advantage of such concept with respect to only sensible or only latent choices is related to the possibility to minimize the thermal losses during system charge and discharge processes by reducing the temperature and pressure drops occurring all along the heat transfer process. Thermodynamic models, heat transfer models, plant integration and control strategies for both a pressurized tank filled with sphere-encapsulated salts and high temperature concrete storage blocks were developed within KTH in-house tool DYESOPT for power plant performance modeling. Once implemented, cross-validated and integrated the new storage model in an existing DYESOPT power plant layout, a sensitivity analysis with regards of storage, solar field and power block sizes was performed to determine the potential impact of integrating the proposed concept. Even for a storage cost figure of 50 USD/kWh, it was found that the integration of the proposed storage configuration can enhance the performance of the power plants by augmenting its availability and reducing its levelized cost of electricity. As expected, it was also found that the benefits are greater for the cases of smaller power block sizes. Specifically, for a power block of 80 MWe a reduction in levelized electricity costs of 8% was estimated together with an increase in capacity factor by 30%, whereas for a power block of 126 MWe the benefits found were a 1.5% cost reduction and 16% availability increase.

  11. Steam Digest 2001

    Energy Technology Data Exchange (ETDEWEB)

    2002-01-01

    Steam Digest 2001 chronicles BestPractices Program's contributions to the industrial trade press for 2001, and presents articles that cover technical, financial and managerial aspects of steam optimization.

  12. High Density Thermal Energy Storage with Supercritical Fluids

    Science.gov (United States)

    Ganapathi, Gani B.; Wirz, Richard

    2012-01-01

    A novel approach to storing thermal energy with supercritical fluids is being investigated, which if successful, promises to transform the way thermal energy is captured and utilized. The use of supercritical fluids allows cost-affordable high-density storage with a combination of latent heat and sensible heat in the two-phase as well as the supercritical state. This technology will enhance penetration of several thermal power generation applications and high temperature water for commercial use if the overall cost of the technology can be demonstrated to be lower than the current state-of-the-art molten salt using sodium nitrate and potassium nitrate eutectic mixtures.

  13. Minimization of steam requirements and enhancement of water-gas shift reaction with warm gas temperature CO2 removal

    Science.gov (United States)

    Siriwardane, Ranjani V; Fisher, II, James C

    2013-12-31

    The disclosure utilizes a hydroxide sorbent for humidification and CO.sub.2 removal from a gaseous stream comprised of CO and CO.sub.2 prior to entry into a water-gas-shift reactor, in order to decrease CO.sub.2 concentration and increase H.sub.2O concentration and shift the water-gas shift reaction toward the forward reaction products CO.sub.2 and H.sub.2. The hydroxide sorbent may be utilized for absorbtion of CO.sub.2 exiting the water-gas shift reactor, producing an enriched H.sub.2 stream. The disclosure further provides for regeneration of the hydroxide sorbent at temperature approximating water-gas shift conditions, and for utilizing H.sub.2O product liberated as a result of the CO.sub.2 absorption.

  14. Petrophysical core characterization at supercritical geothermal conditions

    Science.gov (United States)

    Kummerow, Juliane; Raab, Siegfried

    2015-04-01

    There is a growing scientific interest in the exploitation of supercritical geothermal reservoirs to increase the efficiency of geothermal power plants. The utilisation of geothermal energy requires in any case the detailed knowledge of the reservoir. In reservoir engineering, the characterisation of the geothermal system by electrical resistivity tomography (ERT) is a common geophysical exploration and monitoring strategy. For a realistic interpretation of the field measurements it is necessary to know both, the physical properties of the rock and those of the interacting fluid at defined temperature and pressure conditions. While there have been made great effort in determine the physical and chemical properties of water above its critical point (Tcritical = 374.21° C and pcritical = 221.2 bar), the influence of fluid-rock interactions on petrophysical properties in supercritical aqueous systems is nearly unknown. At supercritical conditions the viscosity of the fluid is low, which enhances the mass transfer and diffusion-controlled chemical reactions. This may have considerable effects on the porosity and hydraulic properties of a rock. To investigate high-enthalpy fluid-rock systems, in the framework of the EU-funded project IMAGE we have built a new percolation set-up, which allows for the measurement of electrical resistivity and permeability of rock samples at controlled supercritical conditions of aqueous fluids (pore pressure = 400 bar and a temperature = 400° C). First results will be presented.

  15. Steam Digest Volume IV

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-07-01

    This edition of the Steam Digest is a compendium of 2003 articles on the technical and financial benefits of steam efficiency, presented by the stakeholders of the U.S. Department of Energy's BestPractices Steam effort.

  16. The Invisibility of Steam

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    2014-01-01

    Almost everyone "knows" that steam is visible. After all, one can see the cloud of white issuing from the spout of a boiling tea kettle. In reality, steam is the gaseous phase of water and is invisible. What you see is light scattered from the tiny droplets of water that are the result of the condensation of the steam as its temperature…

  17. Computational Modeling of Supercritical and Transcritical Flows

    Science.gov (United States)

    2017-01-09

    reasonably accurate for supercritical and transcritical combustion. 15. SUBJECT TERMS N/A 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...pr Reduced pressure (p/pc) Tc Critical temperature Tr Reduced temperature (T/Tc) Vm Molar volume Xi Mole fraction of species i Z Compressibility ω...pressure states. A 5.5mm by 0.4064mm domain uses a uniform 256 × 512 Cartesian grid. The code is fifth order accurate in space and a third order

  18. A three-dimensional laboratory steam injection model allowing in situ saturation measurements. [Comparing steam injection and steam foam injection with nitrogen and without nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Demiral, B.M.R.; Pettit, P.A.; Castanier, L.M.; Brigham, W.E.

    1992-08-01

    The CT imaging technique together with temperature and pressure measurements were used to follow the steam propagation during steam and steam foam injection experiments in a three dimensional laboratory steam injection model. The advantages and disadvantages of different geometries were examined to find out which could best represent radial and gravity override flows and also fit the dimensions of the scanning field of the CT scanner. During experiments, steam was injected continuously at a constant rate into the water saturated model and CT scans were taken at six different cross sections of the model. Pressure and temperature data were collected with time at three different levels in the model. During steam injection experiments, the saturations obtained by CT matched well with the temperature data. That is, the steam override as observed by temperature data was also clearly seen on the CT pictures. During the runs where foam was present, the saturation distributions obtained from CT pictures showed a piston like displacement. However, the temperature distributions were different depending on the type of steam foam process used. The results clearly show that the pressure/temperature data alone are not sufficient to study steam foam in the presence of non-condensible gas.

  19. Effects of supercritical environment on hydrocarbon-fuel injection

    Science.gov (United States)

    Shin, Bongchul; Kim, Dohun; Son, Min; Koo, Jaye

    2017-04-01

    In this study, the effects of environment conditions on decane were investigated. Decane was injected in subcritical and supercritical ambient conditions. The visualization chamber was pressurized to 1.68 MPa by using nitrogen gas at a temperature of 653 K for subcritical ambient conditions. For supercritical ambient conditions, the visualization chamber was pressurized to 2.52 MPa by using helium at a temperature of 653 K. The decane injection in the pressurized chamber was visualized via a shadowgraph technique and gradient images were obtained by a post processing method. A large variation in density gradient was observed at jet interface in the case of subcritical injection in subcritical ambient conditions. Conversely, for supercritical injection in supercritical ambient conditions, a small density gradient was observed at the jet interface. In a manner similar to that observed in other cases, supercritical injection in subcritical ambient conditions differed from supercritical ambient conditions such as sphere shape liquid. Additionally, there were changes in the interface, and the supercritical injection core width was thicker than that in the subcritical injection. Furthermore, in cases with the same injection conditions, the change in the supercritical ambient normalized core width was smaller than the change in the subcritical ambient normalized core width owing to high specific heat at the supercritical injection and small phase change at the interface. Therefore, the interface was affected by the changing ambient condition. Given that the effect of changing the thermodynamic properties of propellants could be essential for a variable thrust rocket engine, the effects of the ambient conditions were investigated experimentally.

  20. Biocompatibility of supercritical CO2-treated titanium implants in a rat model.

    Science.gov (United States)

    Hill, C M; Kang, Q K; Wahl, C; Jimenez, A; Laberge, M; Drews, M; Matthews, M A; An, Y H

    2006-04-01

    Supercritical phase CO2 is a promising method for sterilizing implantable devices and tissue grafts. The goal of this study is to evaluate the biocompatibility of titanium implants sterilized by supercritical phase CO2 in a rat subcutaneous implantation model. At 5 weeks post implantation titanium implants sterilized by supercritical phase CO2 produce a soft tissue reaction that is comparable to other methods of sterilization (steam autoclave, ultraviolet light radiation, ethylene oxide gas, and radio-frequency glow-discharge), as indicated by the thickness and density of the foreign body capsule, although there were some differences on the capillary density. Overall the soft tissue response to the implants was similar among all methods of sterilization, indicating supercritical phase CO2 treatment did not compromise the biocompatibility of the titanium implant.

  1. XPS and IGC characterization of steam treated triticale straw

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Liyan, E-mail: Liyan.zhao@albertainnovates.ca [Cellulose and Hemicellulose Program, Forest Products, Alberta Innovates-Technology Futures, 250 Karl Clark Road, Edmonton, AB T6N 1E4 (Canada); Boluk, Yaman [Cellulose and Hemicellulose Program, Forest Products, Alberta Innovates-Technology Futures, 250 Karl Clark Road, Edmonton, AB T6N 1E4 (Canada)

    2010-10-15

    The surface chemical composition and surface energy of native and steam treated triticale straws have been investigated by X-ray photoelectron spectroscopy (XPS) and inverse gas chromatography (IGC) to reveal the effect of steam treatment temperature and time. The XPS results show that the contents of C elements and C-C group on the exterior surface of native triticale straw are much higher than those on the interior surface, indicating that there was a high quantity of wax on the exterior surface of the native triticale straw. Upon steam treatment, both carbon levels and C-C groups reduce with increasing steam temperature and treatment time of the exterior surfaces. However, the effect of steam treatment on the interior surface is very limited. In terms of the surface acid and base properties, the steam treated samples exhibited higher acid and base properties than the native sample, indicating a more polar surface of the steam treated sample.

  2. XPS and IGC characterization of steam treated triticale straw

    Science.gov (United States)

    Zhao, Liyan; Boluk, Yaman

    2010-10-01

    The surface chemical composition and surface energy of native and steam treated triticale straws have been investigated by X-ray photoelectron spectroscopy (XPS) and inverse gas chromatography (IGC) to reveal the effect of steam treatment temperature and time. The XPS results show that the contents of C elements and C-C group on the exterior surface of native triticale straw are much higher than those on the interior surface, indicating that there was a high quantity of wax on the exterior surface of the native triticale straw. Upon steam treatment, both carbon levels and C-C groups reduce with increasing steam temperature and treatment time of the exterior surfaces. However, the effect of steam treatment on the interior surface is very limited. In terms of the surface acid and base properties, the steam treated samples exhibited higher acid and base properties than the native sample, indicating a more polar surface of the steam treated sample.

  3. Modeling the outflow of liquid with initial supercritical parameters using the relaxation model for condensation

    Directory of Open Access Journals (Sweden)

    Lezhnin Sergey

    2017-01-01

    Full Text Available The two-temperature model of the outflow from a vessel with initial supercritical parameters of medium has been realized. The model uses thermodynamic non-equilibrium relaxation approach to describe phase transitions. Based on a new asymptotic model for computing the relaxation time, the outflow of water with supercritical initial pressure and super- and subcritical temperatures has been calculated.

  4. Supercritical hydrogenation and acid-catalysed reactions "without gases".

    Science.gov (United States)

    Hyde, Jason R; Poliakoff, Martyn

    2004-07-07

    The high temperature catalytic decomposition of HCO2H and HCO2Et are used to generate the high pressure H2 and the supercritical fluids needed for micro-scale hydrogenation of organic compounds; our approach overcomes the problems and limitations of handling high pressure gases on a small-scale and opens the way to the widespread use of continuous supercritical reactions in the laboratory.

  5. Isolation of Organochlorine Pesticide from Ginseng with Supercritical CO2

    Institute of Scientific and Technical Information of China (English)

    李淑芬; 王幼君; 全灿; 田松江

    2005-01-01

    The feasibility of removal of the organochlorine pesticides residues of hexachlorocyclohexane(BHC) from radix ginseng with supercritical CO2 was explored. Some factors, such as extraction pressure, extraction temperature, and kinds of co-solvents were investigated. The experimental results indicate that it is possible to reduce BHC residues in radix ginseng to the level of 0.1 × 10-6 with supercritical CO2 in the presence of suitable amount of co-solvent, such as water.

  6. 高温气冷堆螺旋管直流蒸汽发生器时域模型%Time domain model for once-through helical coil steam generator for high-temperature gas-cooled reactors

    Institute of Scientific and Technical Information of China (English)

    朱宏晔; 居怀明; 段日强; 薄涵亮

    2012-01-01

    The once-through helical coil steam generator(SG) is one of the key parts of high-temperature gas-cooled reactor systems.A time domain model was developed for the steam generator to investigate the dynamic heat transfer and flow processes in both the helium and water/steam sides.A drift-flux model was used for the water/steam two-phase flow,while the helium flow was described by a one-dimensional compressible flow model.The heat transfer and flow resistance were computed by correlations.To improve convergence,a pressure-correction method capable of solving low-speed compressible flows was used for both the helium and water/steam flows.The predicted steady state temperature fields in the steam generator agree well with THTR-300 SG experiments.Typical two-phase flow oscillations can also be captured.%螺旋管直流蒸汽发生器(SG)是高温气冷堆核电站的关键部件。为研究SG内氦气、水/蒸汽流动和换热的动态过程,该文建立了SG时域模型并编制了计算程序。其中,水/蒸汽两相流采用一维漂移流模型描述;氦气采用一维、可压缩流动模型描述;两侧流体与管壁的换热系数和流动阻力系数采用经验关系式计算。求解方法采用适用于动态、低速、可压缩流动的压力修正算法,以克服低Mach数造成的数值不稳定。采用此模型计算了THTR-300SG温度分布,计算结果与实验结果相比平均温度误差小于10℃。动态计算结果表明,此模型可以捕捉到规律的两相流脉动。利用此模型可以进行SG热工设计、不稳定性分析以及电站系统的工艺设计。

  7. Supercritical extraction of lycopene from tomato industrial wastes with ethane.

    Science.gov (United States)

    Nobre, Beatriz P; Gouveia, Luisa; Matos, Patricia G S; Cristino, Ana F; Palavra, António F; Mendes, Rui L

    2012-07-11

    Supercritical fluid extraction of all-E-lycopene from tomato industrial wastes (mixture of skins and seeds) was carried out in a semi-continuous flow apparatus using ethane as supercritical solvent. The effect of pressure, temperature, feed particle size, solvent superficial velocity and matrix initial composition was evaluated. Moreover, the yield of the extraction was compared with that obtained with other supercritical solvents (supercritical CO₂ and a near critical mixture of ethane and propane). The recovery of all-E-lycopene increased with pressure, decreased with the increase of the particle size in the initial stages of the extraction and was not practically affected by the solvent superficial velocity. The effect of the temperature was more complex. When the temperature increased from 40 to 60 °C the recovery of all-E-lycopene increased from 80 to 90%. However, for a further increase to 80 °C, the recovery remained almost the same, indicating that some E-Z isomerization could have occurred, as well as some degradation of lycopene. The recovery of all-E-lycopene was almost the same for feed samples with different all-E-lycopene content. Furthermore, when a batch with a higher all-E-lycopene content was used, supercritical ethane and a near critical mixture of ethane and propane showed to be better solvents than supercritical CO₂ leading to a faster extraction with a higher recovery of the carotenoid.

  8. Materials processing using supercritical fluids

    Directory of Open Access Journals (Sweden)

    Orlović Aleksandar M.

    2005-01-01

    Full Text Available One of the most interesting areas of supercritical fluids applications is the processing of novel materials. These new materials are designed to meet specific requirements and to make possible new applications in Pharmaceuticals design, heterogeneous catalysis, micro- and nano-particles with unique structures, special insulating materials, super capacitors and other special technical materials. Two distinct possibilities to apply supercritical fluids in processing of materials: synthesis of materials in supercritical fluid environment and/or further processing of already obtained materials with the help of supercritical fluids. By adjusting synthesis parameters the properties of supercritical fluids can be significantly altered which further results in the materials with different structures. Unique materials can be also obtained by conducting synthesis in quite specific environments like reversed micelles. This paper is mainly devoted to processing of previously synthesized materials which are further processed using supercritical fluids. Several new methods have been developed to produce micro- and nano-particles with the use of supercritical fluids. The following methods: rapid expansion of supercritical solutions (RESS supercritical anti-solvent (SAS, materials synthesis under supercritical conditions and encapsulation and coating using supercritical fluids were recently developed.

  9. Supercritical Synthesis of Biodiesel

    Directory of Open Access Journals (Sweden)

    Michel Vaultier

    2012-07-01

    Full Text Available The synthesis of biodiesel fuel from lipids (vegetable oils and animal fats has gained in importance as a possible source of renewable non-fossil energy in an attempt to reduce our dependence on petroleum-based fuels. The catalytic processes commonly used for the production of biodiesel fuel present a series of limitations and drawbacks, among them the high energy consumption required for complex purification operations and undesirable side reactions. Supercritical fluid (SCF technologies offer an interesting alternative to conventional processes for preparing biodiesel. This review highlights the advances, advantages, drawbacks and new tendencies involved in the use of supercritical fluids (SCFs for biodiesel synthesis.

  10. Molecular Dynamics Simulation of Diffusion Coefficients of Oxygen, Nitrogen and Sodium Chloride in Supercritical Water

    Institute of Scientific and Technical Information of China (English)

    肖吉; 陆九芳; 陈健; 李以圭

    2001-01-01

    Molecular dynamics simulation has been performed to determine the infinite-dilution diffusion coefficients of oxygen and nitrogen, and the diffusion coefficients of NaCl in supercritical water from 703.2- 763.2 K and 30-45 MPa.The results obtained show that the diffusion coefficients in supercritical water increase with temperature, while decreasing with pressure. Nevertheless, the diffusion coefficients in supercritical water are much larger than those in normal water.

  11. An Improved Steam Injection Model with the Consideration of Steam Override

    Directory of Open Access Journals (Sweden)

    He Congge

    2017-01-01

    Full Text Available The great difference in density between steam and liquid during wet steam injection always results in steam override, that is, steam gathers on the top of the pay zone. In this article, the equation for steam override coefficient was firstly established based on van Lookeren’s steam override theory and then radius of steam zone and hot fluid zone were derived according to a more realistic temperature distribution and an energy balance in the pay zone. On this basis, the equation for the reservoir heat efficiency with the consideration of steam override was developed. Next, predicted results of the new model were compared with these of another analytical model and CMG STARS (a mature commercial reservoir numerical simulator to verify the accuracy of the new mathematical model. Finally, based on the validated model, we analyzed the effects of injection rate, steam quality and reservoir thickness on the reservoir heat efficiency. The results show that the new model can be simplified to the classic model (Marx-Langenheim model under the condition of the steam override being not taken into account, which means the Marx-Langenheim model is corresponding to a special case of this new model. The new model is much closer to the actual situation compared to the Marx-Langenheim model because of considering steam override. Moreover, with the help of the new model, it is found that the reservoir heat efficiency is not much affected by injection rate and steam quality but significantly influenced by reservoir thickness, and to ensure that the reservoir can be heated effectively, the reservoir thickness should not be too small.

  12. Computer modeling of a convective steam superheater

    Science.gov (United States)

    Trojan, Marcin

    2015-03-01

    Superheater is for generating superheated steam from the saturated steam from the evaporator outlet. In the case of pulverized coal fired boiler, a relatively small amount of ash causes problems with ash fouling on the heating surfaces, including the superheaters. In the convection pass of the boiler, the flue gas temperature is lower and ash deposits can be loose or sintered. Ash fouling not only reduces heat transfer from the flue gas to the steam, but also is the cause of a higher pressure drop on the flue gas flow path. In the case the pressure drop is greater than the power consumed by the fan increases. If the superheater surfaces are covered with ash than the steam temperature at the outlet of the superheater stages falls, and the flow rates of the water injected into attemperator should be reduced. There is also an increase in flue gas temperature after the different stages of the superheater. Consequently, this leads to a reduction in boiler efficiency. The paper presents the results of computational fluid dynamics simulations of the first stage superheater of both the boiler OP-210M using the commercial software. The temperature distributions of the steam and flue gas along the way they flow together with temperature of the tube walls and temperature of the ash deposits will be determined. The calculated steam temperature is compared with measurement results. Knowledge of these temperatures is of great practical importance because it allows to choose the grade of steel for a given superheater stage. Using the developed model of the superheater to determine its degree of ash fouling in the on-line mode one can control the activation frequency of steam sootblowers.

  13. Computer modeling of a convective steam superheater

    Directory of Open Access Journals (Sweden)

    Trojan Marcin

    2015-03-01

    Full Text Available Superheater is for generating superheated steam from the saturated steam from the evaporator outlet. In the case of pulverized coal fired boiler, a relatively small amount of ash causes problems with ash fouling on the heating surfaces, including the superheaters. In the convection pass of the boiler, the flue gas temperature is lower and ash deposits can be loose or sintered. Ash fouling not only reduces heat transfer from the flue gas to the steam, but also is the cause of a higher pressure drop on the flue gas flow path. In the case the pressure drop is greater than the power consumed by the fan increases. If the superheater surfaces are covered with ash than the steam temperature at the outlet of the superheater stages falls, and the flow rates of the water injected into attemperator should be reduced. There is also an increase in flue gas temperature after the different stages of the superheater. Consequently, this leads to a reduction in boiler efficiency. The paper presents the results of computational fluid dynamics simulations of the first stage superheater of both the boiler OP-210M using the commercial software. The temperature distributions of the steam and flue gas along the way they flow together with temperature of the tube walls and temperature of the ash deposits will be determined. The calculated steam temperature is compared with measurement results. Knowledge of these temperatures is of great practical importance because it allows to choose the grade of steel for a given superheater stage. Using the developed model of the superheater to determine its degree of ash fouling in the on-line mode one can control the activation frequency of steam sootblowers.

  14. Boiler materials for ultra supercritical coal power plants

    Energy Technology Data Exchange (ETDEWEB)

    Purgert, Robert [Energy Industries of Ohio, Independence, OH (United States); Shingledecker, John [Electric Power Research Inst., Palo Alto, CA (United States); Pschirer, James [Alstom Power Inc., Windsor, CT (Untied States); Ganta, Reddy [Alstom Power Inc., Windsor, CT (Untied States); Weitzel, Paul [The Babcock & Wilcox Company, Baberton, OH (United States); Sarver, Jeff [The Babcock & Wilcox Company, Baberton, OH (United States); Vitalis, Brian [Riley Power Inc., Worchester, WA (United States); Gagliano, Michael [Foster Wheeler North America Corp., Hampton, NJ (United States); Stanko, Greg [Foster Wheeler North America Corp., Hampton, NJ (United States); Tortorelli, Peter [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-29

    The U.S. Department of Energy (DOE) and the Ohio Coal Development Office (OCDO) have undertaken a project aimed at identifying, evaluating, and qualifying the materials needed for the construction of the critical components of coal-fired boilers capable of operating at much higher efficiencies than current generation of supercritical plants. This increased efficiency is expected to be achieved principally through the use of advanced ultrasupercritical (A-USC) steam conditions up to 760°C (1400°F) and 35 MPa (5000 psi). A limiting factor to achieving these higher temperatures and pressures for future A-USC plants are the materials of construction. The goal of this project is to assess/develop materials technology to build and operate an A-USC boiler capable of delivering steam with conditions up to 760°C (1400°F)/35 MPa (5000 psi). The project has successfully met this goal through a focused long-term public-private consortium partnership. The project was based on an R&D plan developed by the Electric Power Research Institute (EPRI) and an industry consortium that supplemented the recommendations of several DOE workshops on the subject of advanced materials. In view of the variety of skills and expertise required for the successful completion of the proposed work, a consortium led by the Energy Industries of Ohio (EIO) with cost-sharing participation of all the major domestic boiler manufacturers, ALSTOM Power (Alstom), Babcock and Wilcox Power Generation Group, Inc. (B&W), Foster Wheeler (FW), and Riley Power, Inc. (Riley), technical management by EPRI and research conducted by Oak Ridge National Laboratory (ORNL) has been developed. The project has clearly identified and tested materials that can withstand 760°C (1400°F) steam conditions and can also make a 700°C (1300°F) plant more economically attractive. In this project, the maximum temperature capabilities of these and other available high-temperature alloys have been assessed to provide a basis for

  15. INFLUENCE OF STEAM EXPLOSION PRETREATMENT ON THE COMPOSITION AND STRUCTURE OF WHEAT STRAW

    OpenAIRE

    Li Cui; Zhong Liu; Chuanling Si,; Lanfeng Hui; Neng Kang,; Ting Zhao

    2012-01-01

    Steam explosion pretreatment of wheat straw can solubilize a significant portion of the hemicellulosic component and enhance the enzymatic digestibility of the remaining cellulose for fermentation into ethanol. In this work, wheat straw was pretreated by steam explosion using different steam temperatures and retention times, and the chemical compositions of the raw and steam-exploded wheat straw were analyzed. Results showed that the content of hemicellulose decreased sharply at higher steam ...

  16. Steam-water relative permeability

    Energy Technology Data Exchange (ETDEWEB)

    Ambusso, W.; Satik, C.; Home, R.N. [Stanford Univ., CA (United States)

    1997-12-31

    A set of relative permeability relations for simultaneous flow of steam and water in porous media have been measured in steady state experiments conducted under the conditions that eliminate most errors associated with saturation and pressure measurements. These relations show that the relative permeabilities for steam-water flow in porous media vary approximately linearly with saturation. This departure from the nitrogen/water behavior indicates that there are fundamental differences between steam/water and nitrogen/water flows. The saturations in these experiments were measured by using a high resolution X-ray computer tomography (CT) scanner. In addition the pressure gradients were obtained from the measurements of liquid phase pressure over the portions with flat saturation profiles. These two aspects constitute a major improvement in the experimental method compared to those used in the past. Comparison of the saturation profiles measured by the X-ray CT scanner during the experiments shows a good agreement with those predicted by numerical simulations. To obtain results that are applicable to general flow of steam and water in porous media similar experiments will be conducted at higher temperature and with porous rocks of different wetting characteristics and porosity distribution.

  17. Supercritical fluid technology for energy and environmental applications

    CERN Document Server

    Anikeev, Vladimir

    2014-01-01

    Supercritical Fluid Technology for Energy and Environmental Applications covers the fundamental principles involved in the preparation and characterization of supercritical fluids (SCFs) used in the energy production and other environmental applications. Energy production from diversified resources - including renewable materials - using clean processes can be accomplished using technologies like SCFs. This book is focused on critical issues scientists and engineers face in applying SCFs to energy production and environmental protection, the innovative solutions they have found, and the challenges they need to overcome. The book also covers the basics of sub- and supercritical fluids, like the thermodynamics of phase and chemical equilibria, mathematical modeling, and process calculations. A supercritical fluid is any substance at a temperature and pressure above its critical point where distinct liquid and gas phases do not exist. At this state the compound demonstrates unique properties, which can be "fine...

  18. Influence of various aspects of low Reynolds number k-ε turbulence models on predicting in-tube buoyancy affected heat transfer to supercritical pressure fluids

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chen-Ru; Zhang, Zhen [Institute of Nuclear and New Energy Technology of Tsinghua University, Advanced Nuclear Energy Technology Cooperation Innovation Centre, Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 100084 (China); Jiang, Pei-Xue, E-mail: jiangpx@tsinghua.edu.cn [Beijing Key Laboratory of CO_2 Utilization and Reduction Technology/Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Bo, Han-Liang [Institute of Nuclear and New Energy Technology of Tsinghua University, Advanced Nuclear Energy Technology Cooperation Innovation Centre, Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 100084 (China)

    2017-03-15

    Highlights: • Understanding of the mechanism of buoyancy effect on supercritical heat transfer. • Turbulence related parameters in upward and downward flows were compared. • Turbulent Prandtl number affected the prediction insignificantly. • Buoyancy production was insignificant compared with shear production. • Damping function had the greatest effect and is a priority for further modification. - Abstract: Heat transfer to supercritical pressure fluids was modeled for normal and buoyancy affected conditions using several low Reynolds number k-ε models, including the Launder and Sharma, Myong and Kasagi, and Abe, Kondoh and Nagano, with the predictions compared with experimental data. All three turbulence models accurately predicted the cases without heat transfer deterioration, but failed to accurately predict the cases with heat transfer deterioration although the general trends were captured, indicating that further improvements and modifications are needed for the low Reynolds number k-ε turbulence models to better predict buoyancy deteriorated heat transfer. Further investigations studied the influence of various aspects of the low Reynolds number k-ε turbulence models, including the turbulent Prandtl number, the buoyancy production of turbulent kinetic energy, and the damping function to provide guidelines for model development to more precisely predict buoyancy affected heat transfer. The results show that the turbulent Prandtl number and the buoyancy production of turbulent kinetic energy have little influence on the predictions for cases in this study, while new damping functions with carefully selected control parameters are needed in the low Reynolds number k-ε turbulence models to correctly predict the buoyancy effect for heat transfer simulations in various applications such as supercritical pressure steam generators (SPSGs) in the high temperature gas cooled reactor (HTR) and the supercritical pressure water reactor (SCWR).

  19. Ni-Based Catalysts for Low Temperature Methane Steam Reforming: Recent Results on Ni-Au and Comparison with Other Bi-Metallic Systems

    Directory of Open Access Journals (Sweden)

    Anna M. Venezia

    2013-06-01

    Full Text Available Steam reforming of light hydrocarbons provides a promising method for hydrogen production. Ni-based catalysts are so far the best and the most commonly used catalysts for steam reforming because of their acceptably high activity and significantly lower cost in comparison with alternative precious metal-based catalysts. However, nickel catalysts are susceptible to deactivation from the deposition of carbon, even when operating at steam-to-carbon ratios predicted to be thermodynamically outside of the carbon-forming regime. Reactivity and deactivation by carbon formation can be tuned by modifying Ni surfaces with a second metal, such as Au through alloy formation. In the present review, we summarize the very recent progress in the design, synthesis, and characterization of supported bimetallic Ni-based catalysts for steam reforming. The progress in the modification of Ni with noble metals (such as Au and Ag is discussed in terms of preparation, characterization and pretreatment methods. Moreover, the comparison with the effects of other metals (such as Sn, Cu, Co, Mo, Fe, Gd and B is addressed. The differences of catalytic activity, thermal stability and carbon species between bimetallic and monometallic Ni-based catalysts are also briefly shown.

  20. Supercritical separation process for complex organic mixtures

    Science.gov (United States)

    Chum, Helena L.; Filardo, Giuseppe

    1990-01-01

    A process is disclosed for separating low molecular weight components from complex aqueous organic mixtures. The process includes preparing a separation solution of supercritical carbon dioxide with an effective amount of an entrainer to modify the solvation power of the supercritical carbon dioxide and extract preselected low molecular weight components. The separation solution is maintained at a temperature of at least about 70.degree. C. and a pressure of at least about 1,500 psi. The separation solution is then contacted with the organic mixtures while maintaining the temperature and pressure as above until the mixtures and solution reach equilibrium to extract the preselected low molecular weight components from the organic mixtures. Finally, the entrainer/extracted components portion of the equilibrium mixture is isolated from the separation solution.

  1. Supercritical Fluid Extraction of Flavonoids from Dandelion

    Directory of Open Access Journals (Sweden)

    Wu Jun

    2014-01-01

    Full Text Available In this study, the total flavonoids from dandelion was extracted by supercritical CO2 and the total flavonoids content in the extract was investigated by the sodium nitrite-aluminum nitrate method with Rutin as a standard product. Single-factor experiments were carried out to map the effects of extraction pressure, temperature, time and entrainer amount on the yield of flavonoids. The orthogonal experiments on the optimum technology parameters demonstrated that the influence of the experimental conditions over the yield from high to low was: (a pressure, (b temperature, (c entrainer amount, (d time. The optimization result showed that under the conditions of 50°C, 35 MPa, 80 min and 4.0 mL/g entrainer amount, the yield of the preparative supercritical fluid extraction was 4.974%.

  2. Reactions of supercritical water and supercritical methanol with benzaldehyde; Chorinkaisui oyobi chorinkai methanol to benzaldehyde tono hanno

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, C.; Yasuda, T.; Nishi, K.; Takahashi, S. [Tohoku University, Sendai (Japan). Institute for Chemical Reaction Science

    1996-11-01

    The reactions of supercritical water and supercritical methanol with benzaldehyde have been examined in the temperature range from 553 to 693 K, and the reaction pathways have been examined from the temporal variations of the reaction products. For the reaction of benzaldehyde with supercritical water, the major product was benzene, which was formed from the pyrolysis of benzaldehyde. The benzoic acid and benzyl alcohol were the by-products, produced from the Cannizzaro-type disproportionation reaction of benzaldehyde with the hydrate formed from the reaction with water and benzaldehyde. The major product for the reaction of benzaldehyde with supercritical methanol was benzyl alcohol, and the by-product were dimethylacetal, benzene, and methyl benzoic acid. Under the reaction conditions of this study, a significant amount of acetal was produced from benzaldehyde and methanol. The pyrolysis of acetal yielded benzyl alcohol. 29 refs., 6 figs., 4 tabs.

  3. Dye solubility in supercritical carbon dioxide fluid

    Directory of Open Access Journals (Sweden)

    Yan Jun

    2015-01-01

    Full Text Available Supercritical carbon dioxide fluid is an alternative solvent for the water of the traditional dyeing. The solubility of dyestuff affects greatly the dyeing process. A theoretical model for predicting the dye solubility is proposed and verified experimentally. The paper concludes that the pressure has a greater impact on the dyestuff solubility than temperature, and an optimal dyeing condition is suggested for the highest distribution coefficient of dyestuff.

  4. Supercritical CO2 Extraction of Ethanol

    OpenAIRE

    GÜVENÇ, A.; MEHMETOĞLU, Ü.; ÇALIMLI, A.

    1999-01-01

    Extraction of ethanol was studied from both synthetic ethanol solution and fermentation broth using supercritical CO2 in an extraction apparatus in ranges of 313 to 333 K and 80 to 160 atmospheres, for varying extraction times. The experimental system consists mainly of four parts: a CO2 storage system, a high-pressure liquid pump, an extractor and a product collection unit. Samples were analyzed by gas chromatography. Effects of temperature, pressure, extraction time, initial ethan...

  5. Analysis on High Temperature Strength and Sealing Behavior of U-type Seal in Steam Turbine Valves%汽轮机进汽阀U型密封高温强度与密封性能分析

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      U型密封因其优越的密封性能而被广泛应用在超超临界汽轮机进汽阀门中。随着运行参数(温度,压力)不断提升, U 型密封承受的蠕变越发严重。为了研究 U 型密封在高参数运行条件下的蠕变强度与密封性能,引用经过时间硬化修正的 Norton-Bailay 蠕变本构方程和基于孔洞长大理论的多轴蠕变模型,分析计算了汽轮机进气阀U型密封2×105 h工作时域内接触面位置、接触应力和蠕变多轴度因子的变化规律。结果表明:随蠕变时间增加,U型密封的接触应力下降明显;U型密封的关键部位受到较大多轴应力影响,并产生较大的 Cocks-Ashby 蠕变等效应变,试验结果与预测结果一致。%U-type seal has been widely used in the inlet valves of ultra-supercritical steam turbines due to its superior sealing performance. However, the U-type seal bears greater creep deformation with the increase of the operational parameters (T, P). In order to investigate the creep strength and sealing performance of the U-type seal, the modified time-hardening Norton-Bailay constitutive equation and multiaxial cavity growth model were employed in the calculation. Furthermore, the variation of contact position, contact stress and multiaxial factor of U-type seal of steam turbine valve were analyzed under 0.2 million creep hours. The results illustrate that the contact stress of U-type seal significantly reduces with the creep hours increases. Some key areas of U-type seal suffer great multi-axial state of stress, and then huge Cock-Ashby equivalent strain is produced. The experimental result is consistent with predicted result.

  6. World largest KAWASAKI KJ type soda recovery boiler, generating high pressure and high temperature steam. For the Iwakuni mill of Nippon Paper Industries Co. Ltd.; Sekai saidaikyu no koatsu koon soda kaishu boiler. Nippon seishi (kabu) Iwakuni kojo dono muke

    Energy Technology Data Exchange (ETDEWEB)

    Hirokawa, M.; Matsuda, T.; Masuda, T.; Suemitsu, N.; Makito, Y.; Tanihara, T.; Asada, S. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1996-10-15

    This paper presents the important notices in design and issues on the large KAWASAKI KJ type soda recovery boiler under construction for the Iwakuni mill of Nippon Paper Industries Co., Ltd. This soda recovery boiler is the largest one in volume in Japan, and the highest one in pressure and temperature in the world. Since saturation temperature rises with steam pressure, corrosion resistance of the water cooling wall of a combustion chamber should be considered enough. This boiler thus adopts the double contact tube with an outer tube of SUS310 most superior in corrosion resistance. Alkaline molten salt corrosion of a superheater is one of the most severe problems on steam temperature rise. This boiler thus adopts SUS309J2TB superior in alkaline molten salt corrosion resistance for the highest-temperature portion of a superheater and the lower U bent subjected to radiant heat from a combustion chamber. Flow in a furnace and stress of a superheater were analyzed using computer for scale-up of boiler and preliminary verification. 1 ref., 14 figs., 2 tabs.

  7. Study of safety relief valve operation under ATWS conditions. [Supercritical flow

    Energy Technology Data Exchange (ETDEWEB)

    Hutmacher, E.S.; Whitten, S.D.

    1979-09-01

    In March 1979, the NRC published a report (NUREG/CR-0687) prepared by the Energy Technology Engineering Center (ETEC-TDR-78-19). That report presented a literature survey which updated earlier NRC studies of saturated or subcooled water flow through relief valves, under ATWS conditions. This supplement expands upon that search to include supercritical steam-water flow. No applicable data for the supercritical conditions were found, nor were any newer data on saturated or subcooled conditions uncovered. This supplement also updates a look for facilities currently capable of simultaneously imposing all ATWS conditions upon test relief valves. Results confirmed the negative findings of NUREG/CR-0687.

  8. An Isothermal Steam Expander for an Industrial Steam Supplying System

    OpenAIRE

    Chen-Kuang Lin; Guang-Jer Lai; Yoshiyuki Kobayashi; Masahiro Matsuo; Min-Chie Chiu

    2015-01-01

    Steam is an essential medium used in the industrial process. To ensure steam quality, small and middle scale boilers are often adopted. However, because a higher steam pressure (compared to the necessary steam pressure) is generated, the boiler’s steam pressure will be reduced via a pressure regulator before the steam is directed through the process. Unfortunately, pressure is somewhat wasted during the reducing process. Therefore, in order to promote energy efficiency, a pressure regulator i...

  9. Mathematical modeling of control system for the experimental steam generator

    Directory of Open Access Journals (Sweden)

    Podlasek Szymon

    2016-01-01

    Full Text Available A steam generator is an essential unit of each cogeneration system using steam machines. Currently one of the cheapest ways of the steam generation can be application of old steam generators came from army surplus store. They have relatively simple construction and in case of not so exploited units – quite good general conditions, and functionality of mechanical components. By contrast, electrical components and control systems (mostly based on relay automatics are definitely obsolete. It is not possible to use such units with cooperation of steam bus or with steam engines. In particular, there is no possibility for automatically adjustment of the pressure and the temperature of the generated steam supplying steam engines. Such adjustment is necessary in case of variation of a generator load. The paper is devoted to description of improvement of an exemplary unit together with construction of the measurement-control system based on a PLC. The aim was to enable for communication between the steam generator and controllers of the steam bus and steam engines in order to construction of a complete, fully autonomic and maintenance-free microcogeneration system.

  10. Mathematical modeling of control system for the experimental steam generator

    Science.gov (United States)

    Podlasek, Szymon; Lalik, Krzysztof; Filipowicz, Mariusz; Sornek, Krzysztof; Kupski, Robert; Raś, Anita

    2016-03-01

    A steam generator is an essential unit of each cogeneration system using steam machines. Currently one of the cheapest ways of the steam generation can be application of old steam generators came from army surplus store. They have relatively simple construction and in case of not so exploited units - quite good general conditions, and functionality of mechanical components. By contrast, electrical components and control systems (mostly based on relay automatics) are definitely obsolete. It is not possible to use such units with cooperation of steam bus or with steam engines. In particular, there is no possibility for automatically adjustment of the pressure and the temperature of the generated steam supplying steam engines. Such adjustment is necessary in case of variation of a generator load. The paper is devoted to description of improvement of an exemplary unit together with construction of the measurement-control system based on a PLC. The aim was to enable for communication between the steam generator and controllers of the steam bus and steam engines in order to construction of a complete, fully autonomic and maintenance-free microcogeneration system.

  11. Oxidation behavior of ferritic-martensitic and ODS steels in supercritical water

    Science.gov (United States)

    Bischoff, Jeremy

    Ferritic-martensitic and ODS alloys are primary candidates for application as cladding and structural material in Generation IV nuclear power plants, especially the supercritical water reactor. One of the main in-service degradation mechanisms for these alloys is uniform corrosion, thus this project focuses on understanding the oxidation behavior of these alloys in the supercritical water (SCW) environment. This understanding is acquired through the analysis of the oxide microstructure using microbeam synchrotron radiation diffraction and fluorescence associated with electron microscopy (both SEM and TEM). The microbeam synchrotron radiation diffraction and fluorescence technique provides unique microstructural data of the oxide. This technique simultaneously probes elemental and phase information step by step with a sub-micron spatial resolution throughout the oxide layers. Thus we were able to locate specific phases, such as Cr2O3, at specific locations in the oxide layer, mainly the interfaces. The electron microscopy complemented this analysis by imaging the oxide layers, to yield detailed information on the oxide morphology. All the alloys studied exhibited the same three-layer structure with an outer layer containing only Fe3O4, an inner layer containing a mixture of Fe3O4 and FeCr2O 4, and a diffusion layer containing a mixture of chromium-rich precipitates (Cr2O3 and FeCr2O4) and metal grains. By analyzing samples with various exposure times, we were able to follow the evolution of the oxide microstructure with exposure time. To obtain the corroded samples, several corrosion experiments were performed: some in supercritical water (at 500°C and 600°C) and one experiment in 500°C steam. The test in steam was undertaken to obtain more data points in the kinetic curves, because we thought the corrosion in steam and supercritical water at the same temperature would result in similar kinetics. This turned out not to be the case and the samples in supercritical

  12. Supercritical fluid reverse micelle separation

    Science.gov (United States)

    Fulton, John L.; Smith, Richard D.

    1993-01-01

    A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W.sub.o that determines the maximum size of the reverse micelles. The maximum ratio W.sub.o of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions.

  13. Supercritical fluid reverse micelle separation

    Science.gov (United States)

    Fulton, J.L.; Smith, R.D.

    1993-11-30

    A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W[sub o] that determines the maximum size of the reverse micelles. The maximum ratio W[sub o] of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions. 27 figures.

  14. Study on Temperature Controlled System of Supercritical Fluid Foaming Extruder%超临界流体发泡挤出机温度控制系统研究

    Institute of Scientific and Technical Information of China (English)

    徐天艺

    2013-01-01

    Introduction was made to a supercritical fluid foaming extruder temperature control system. Analysis was made to fac-tors impacting on the accuracy of equipment temperature control system, the improved measures were raised. Combined with thyris-tor adjusting output power of heating and cooling system, the double-channel PID was used to reduce thermal inertia and hysteresis. Experimental result shows that the temperature control accuracy can reach ±1℃, which greatly lifted quality and finished product percentage of extrusion foaming products.%介绍了超临界流体发泡挤出机的温度控制系统,分析了影响挤出设备温控系统精度的因素,并提出了改进措施,即利用双通道PID结合可控硅调整加热冷却系统的输出功率,降低了系统的热惯性与迟滞性。实验结果表明,控温精度可达到±1℃,极大地提高了挤出发泡制品的质量和成品率。

  15. Material developments for supercritical boilers and pipework. Bridging the gap?

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, P.M.; Buchanan, L.W.; Barrie, M. [Doosan Power Systems Ltd, Renfrew (United Kingdom). Technology and Engineering

    2010-07-01

    This paper briefly reviews the current state of developments for ferritic, austenitic and nickel alloys for supercritical steam raising power plant applications. Some of the challenges are touches upon as well as various activities ongoing to meet these challenges. It is likely that, although the technical challenges are significant, developments in ferritic alloys will allow a more incremental increase in plant efficiency than the step change required to justify the cost of nickel alloys. This conclusion may change as the cost of fuel increases such that the economic and commercial risks of using nickel are compensated by the saving in fuel costs. (orig.)

  16. MALEIC ANHYDRIDE HYDROGENATION OF PD/AL2O3 CATALYST UNDER SUPERCRITICAL CO2 MEDIUM

    Science.gov (United States)

    Hydrogenation of maleic anhydride (MA) to either y-butyrolactone of succinic anhydride over simple Pd/Al2O3 impregnated catalyst in supercritical CO2 medium has been studied at different temperatures and pressures. A comparison of the supercritical CO2 medium reaction with the c...

  17. Study on Supercritical Fluid Extraction of Pu(Ⅳ)in Simulative Contaminated Soils

    Institute of Scientific and Technical Information of China (English)

    SONG; Zhi-jun; DING; You-qian; ZHOU; Li-qiang

    2015-01-01

    Supercritical fluid has advantages of rapid mass transfer and high solubility,which can extract different substance through changing the extracting temperature and pressure.So in comparison to conventional solvent extraction process,supercritical fluid extraction do not need to pretreatment of the matrix,minimizes the amount of secondary waste,and the extraction

  18. Supercritical water gasification of biomass: an experimental study of model compounds and potential biomass feeds

    NARCIS (Netherlands)

    Chakinala, Anand Gupta

    2013-01-01

    Gasification of biomass in supercritical water is a complex process. In supercritical water ideally the biomass structure and the larger molecules are broken down into smaller, gaseous components under the influence of radicals. However, the biomass is normally fed to the system at low temperature a

  19. Equations for calculating the properties of dissociated steam

    Science.gov (United States)

    Aminov, R. Z.; Gudym, A. A.

    2017-08-01

    The equations of state for dissociated steam have been developed in the temperature and pressure ranges of 1250-2300 K and 0.01-10.00 MPa for calculating thermodynamic processes in thermal power units operating on high-temperature steam. These equations are based on the property tables for dissociated steam derived at a reference temperature of 0 K. It is assumed that the initial substance is steam, the dissociation of which—in accordance with the most likely chemical reactions—results in formation of molecules of hydrogen, oxygen, steam, hydroxyl, and atoms of oxygen and hydrogen. Differential thermodynamic correlations, considering a change in the chemical potential and the composition of the mixture, during the steam dissociation are used. A reference temperature of 0.01°C used in the calculation of parameters of nondissociated steam has been adopted to predict processes in thermal power units without matching the reference temperatures and to account for transformation of dissociated steam into its usual form for which there is the international system of equations with the water triple point of 0.01°C taken as the reference. In the investigated region, the deviation of dissociated steam properties from those of nondissociated steam, which increases with decreasing the pressure or increasing the temperature, was determined. For a pressure of 0.02 MPa and a temperature of 2200 K, these deviations are 512 kJ/kg for the enthalpy, 0.2574 kJ/(kg K) for the entropy, and 3.431 kJ/(kg K) for the heat capacity at constant pressure. The maximum deviation of the dissociated steam properties calculated by the developed equations from the handbook values that these equations are based on does not exceed 0.03-0.05%.

  20. Pretreatment of Corn Stalk by Steam Explosion

    Institute of Scientific and Technical Information of China (English)

    邵自强; 田永生; 谭惠民

    2003-01-01

    A steam explosion pretreatment, which is one of the best ways of pretreating plant stalk, is applied at various severities to corn stalk. It could effectively modify the super-molecular structure of corn stalk and defibrating corn stalk into individual components. The relationship between yield of reducing sugar and the operating conditions, including temperature, pressure of steam explosion pretreatment and acidity, is also established. Experimental results prove that the steam explosion substantially increases the yield of reducing sugar, and the optimal condition for steam explosion is as follows: the pressure is 2.0 MPa, the pressure-retaining time 300 s, the initial acid concentration 1% and the acid treatment time 24 h.

  1. Thermodynamics of supersaturated steam: Molecular simulation results

    Science.gov (United States)

    Moučka, Filip; Nezbeda, Ivo

    2016-12-01

    Supersaturated steam modeled by the Gaussian charge polarizable model [P. Paricaud, M. Předota, and A. A. Chialvo, J. Chem. Phys. 122, 244511 (2005)] and BK3 model [P. Kiss and A. Baranyai, J. Chem. Phys. 138, 204507 (2013)] has been simulated at conditions occurring in steam turbines using the multiple-particle-move Monte Carlo for both the homogeneous phase and also implemented for the Gibbs ensemble Monte Carlo molecular simulation methods. Because of these thermodynamic conditions, a specific simulation algorithm has been developed to bypass common simulation problems resulting from very low densities of steam and cluster formation therein. In addition to pressure-temperature-density and orthobaric data, the distribution of clusters has also been evaluated. The obtained extensive data of high precision should serve as a basis for development of reliable molecular-based equations for properties of metastable steam.

  2. 300MW锅炉再热汽温低的原因分析及改造%Cause Analysis for Low Reheat Steam Temperature and Transformations of 300-MW Boilers

    Institute of Scientific and Technical Information of China (English)

    赵振宁; 王晶晶; 徐立伟; 姚万业; 童家麟

    2012-01-01

    某电厂300 MW亚临界锅炉在汽轮机经过通流改造后,出现了低负荷时再热蒸汽温度偏低的现象,通过对再热蒸汽温度调整试验数据的分析,得到再热蒸汽人口温度与其设计值偏差较大是导致再热蒸汽温度偏低的主要原因.根据锅炉热平衡计算的结果,提出了再热器增容改造的3种方案,通过分析对比,选出了最优方案并进行改造.由锅炉改造后的性能试验看出改造效果良好,再热蒸汽温度有了明显的升高,达到了再热汽温541℃的要求.与此同时,电厂的经济效益也得到了显著提高.%For the 300-MW subcritical boiler in a power plant, the steam temperature at the outlet of the reheater has always been lower than the designed value after the turbine through-flow transformation. Through the analysis on the data from the reheat steam temperature adjustment test, it is observed that the steam temperature at the inlet of the reheater is much lower than the designed value. Based on the thermal balance calculation, three schemes for increasing the capacity of the reheater are proposed. After comparison, the most reasonable one is selected and put into practice. The performance test after the transformation indicates that the reheat steam temperature at the outlet of the reheater is improved significantly, reaching the designed value of 541℃ with the economic efficiency of the plant also improved greatly.

  3. Reciprocating wear in a steam environment

    Energy Technology Data Exchange (ETDEWEB)

    Brown, L.J.; Gee, M.G. [National Physical Laboratory, Teddington, Middlesex (United Kingdom)

    2010-07-01

    Tests to simulate the wear between sliding components in steam power plant have been performed using a low frequency wear apparatus at elevated temperatures under static load, at ambient pressure, in a steam environment. The apparatus was modified to accept a novel method of steam delivery. The materials tested were pre-exposed in a flowing steam furnace at temperature for either 500 or 3000 hours to provide some simulation of long term ageing. The duration of each wear test was 50 hours and tests were also performed on as-received material for comparison purposes. Data has been compared with results of tests performed on non-oxidised material for longer durations and also on tests without steam to examine the effect of different environments. Data collected from each test consists of mass change, stub height measurement and friction coefficient as well as visual inspection of the wear track. Within this paper, it is reported that both pre-ageing and the addition of steam during testing clearly influence the friction between material surfaces. (orig.)

  4. Temperature Sensitivity Analysis of High Temperature Steam Electrolysis System for Hydrogen Production%高温蒸汽电解制氢系统温度敏感性分析

    Institute of Scientific and Technical Information of China (English)

    刘明义; 于波; 徐景明; 陈靖

    2009-01-01

    In this study, the temperature sensitive analysis model of the high temperature steam electrolysis (HTSE) system was established through electrochemical method. Temperature sensitivity of the HTSE system was analyzed using this model. The concept of temperature sensitive coefficient was put forward originally. Qualitative researches show the temperature sensitive coefficient increase with operation temperatures increasing under various electrical efficiency (ηel), electrolysis efficiency (ηes), and thermal efficiency (ηth), which indicate the overall system efficiency of the HTSE system increases with operation temperatures increasing. And the temperature sensitive coefficient increase with ηel and ηth increasing, while ηes has little effect on the temperature sensitive coefficient. Quantitative researches show the temperature sensitive coefficient is 1.4 with the operation temperatures in the range of 750-950 ℃, which indicates the overall system efficiency increases about 10.5% and 12%, when the operation temperatures of the HTSE system are 800 and 900 ℃, respectively. Then the overall system efficiency of the actual HTGR coupled with HTSE system is as high as 55.8% and 56.5%, respectively, which is about two times higher than that of the conventional alkaline water electrolysis.%通过电化学方法建立高温蒸汽电解制氢系统温度敏感性分析的数学模型,通过该模型对系统温度敏感性进行分析,并提出温度敏感系数的概念.定性的研究结果表明,在不同发电效率、电解效率以及热效率下,温度敏感系数均随着工作温度的增加而增大.这表明,系统总效率随着温度的升高而增大,且随着发电效率和热效率的增加,温度敏感系数也随之增大,但电解效率对温度敏感系数影响较小.定量的研究结果表明,工作温度为750~950 ℃的高温蒸汽电解制氢系统的温度敏感系数约为1.40,即系统工作温度分别为800和900 ℃时,由于温

  5. Steam treatment of zebra mussels

    Energy Technology Data Exchange (ETDEWEB)

    Tsou, J. [Electric Power Research Institute, Palo Alto, CA (United States); Rybarik, D.L.; Thiel, J. [Dairyland Power Cooperative, La Crosse, WI (United States); Mussalli, Y.G.; Collins, F. [Stone & Webster Environmental Technology & Services, Boston, MA (United States)

    1996-08-01

    Steam injection into intake bays is a nonchemical method to control zebra mussels. This technique was demonstrated at Dairyland Power Cooperative`s J.P. Madgett Station located in Alma, Wisconsin. The project was funded by the EPRI Zebra Mussel Consortium which includes: Dairyland Power Cooperative, Central Illinois Public Service, Duke Power, Illinois Power Company, PSI Energy, Public Service Electric & Gas, and Tennessee Valley Authority. This technique can be used by other power plants around the nation. The steam treatments were performed at the J.P. Madgen intake in Alma, Wisconsin, on September 14 and 18, 1994. The J.P. Madgen Station has two water intake bays with capacities of approximately 295,000 gallons and 265,000 gallons each. Each intake can be isolated, permitting either full or reduced generation depending on river temperature conditions. In addition to the intake bays, the outside fire protection loop and hydrants were also treated with the hot water from one of the bays. This paper presents the process design, piping and steam educator configurations, portable industrial boiler sizing and description, and the thermocouples to monitor the water temperature in the intake bay. The biological mortality and control test protocol and treatment results are also presented. Treatment effectiveness was 100%, however equipment installation and operation was more problematic than anticipated. 3 refs., 5 figs., 2 tabs.

  6. Hydrogenation of diesel aromatic compounds in supercritical solvent environment

    Directory of Open Access Journals (Sweden)

    E.P. Martins

    2000-09-01

    Full Text Available Reactions under supercritical conditions have been employed in many processes. Furthermore, an increasing number of commercial reactions have been conducted under supercritical or near critical conditions. These reaction conditions offer several advantages when compared to conditions in conventional catalytic processes in liquid-phase, gas-liquid interface, or even some gas-phase reactions. Basically, a supercritical solvent can diminish the reactant’s transport resistance from the bulk region to the catalyst surface due to enhancement of liquid diffusivity values and better solubility than those in different phases. Another advantage is that supercritical solvents permit prompt and easy changes in intermolecular properties in order to modify reaction parameters, such as conversion or selectivity, or even proceed with the separation of reaction products. Diesel fractions from petroleum frequently have larger than desirable quantities of aromatic compounds. Diesel hydrogenation is intended to decrease these quantities, i.e., to increase the quantity of paraffin present in this petroleum fraction. In this work, the hydrogenation of tetralin was studied as a model reaction for the aromatic hydrogenation process. A conventional gas-liquid-solid catalytic process was compared with that of supercritical carbon dioxide substrate under similar conditions. Additionally, an equilibrium conversion diagram was calculated for this reaction in a wide range of temperature and reactant ratios, so as to optimize the operational conditions and improve the results of subsequent experiments. An increase in the rate of reaction at 493 K in supercritical fluid, as compared to that in the conventional process, was observed.

  7. Hydrogenation of diesel aromatic compounds in supercritical solvent environment

    Energy Technology Data Exchange (ETDEWEB)

    Martins, E.P.; Aranda, D.A.G.; Pessoa, F.L.P. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica. Dept. de Engenharia Quimica. E-mail: donato@h2o.eq.ufrj.br; pessoa@h2o.eq.ufrj.br; Zotin, J.L. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. E-mail: zotin@cenpes.petrobras.com.br

    2000-09-01

    Reactions under supercritical conditions have been employed in many processes. Furthermore, an increasing number of commercial reactions have been conducted under supercritical or near critical conditions. These reaction conditions offer several advantages when compared to conditions in conventional catalytic processes in liquid-phase, gas-liquid interface., or even some gas-phase reactions. basically, a supercritical solvent can diminish the reactant's transport resistance from the bulk region to the catalyst surface due to enhancement of liquid diffusivity values and better solubility than those in different phases. Another advantage is that supercritical solvents permit prompt and easy changes in intermolecular properties in order to modify reaction parameters, such as conversion or selectivity, or even proceed with the separation of reaction products. Diesel fractions from petroleum frequently have larger than desirable quantities of aromatic compounds. Diesel hydrogenation is intended to decrease these quantities, to increase the quantity of paraffin present in this petroleum fraction. In this work, the hydrogenation of tetralin was studied as a model reaction for the aromatic hydrogenation process. A conventional gas-liquid-solid catalytic process was compared with that of supercritical carbon dioxide substrate under similar conditions. Additionally, an equilibrium conversion diagram was calculated for this reaction in a wide range of temperature and reactant ratios, so as to optimize the operational conditions and improve the results of subsequent experiments. An increase in the rate of reaction at 493 K in supercritical fluid, as compared to that in the conventional process, was observed. (author)

  8. Fischer-Tropsch synthesis in supercritical fluids. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Akgerman, A.; Bukur, D.B.

    1998-12-31

    The objective of this study was to investigate Fischer-Tropsch Synthesis (FTS) in the supercritical phase employing a commercial precipitated iron catalysts. As the supercritical fluid the authors used propane and n-hexane. The catalyst had a nominal composition of 100 Fe/5 Cu/4.2 K/25 SiO{sub 2} on mass basis and was used in a fixed bed reactor under both normal (conventional) and supercritical conditions. Experimental data were obtained at different temperatures (235 C, 250 C, and 260 C) and synthesis gas feed compositions (H{sub 2}/CO molar feed ratio of 0.67, 1.0 and 2.0) in both modes of operation under steady state conditions. The authors compared the performance of the precipitated iron catalyst in the supercritical phase, with the data obtained in gas phase (fixed bed reactor) and slurry phase (STS reactor). Comparisons were made in terms of bulk catalyst activity and various aspects of product selectivity (e.g. lumped hydrocarbon distribution and olefin content as a function of carbon number). In order to gain better understanding of the role of intraparticle mass transfer during FTS under conventional or supercritical conditions, the authors have measured diffusivities of representative hydrocarbon products in supercritical fluids, as well as their effective diffusion rates into the pores of catalyst at the reaction conditions. They constructed a Taylor dispersion apparatus to measure diffusion coefficients of hydrocarbon products of FTS in sub and supercritical ethane, propane, and hexane. In addition, they developed a tracer response technique to measure the effective diffusivities in the catalyst pores at the same conditions. Based on these results they have developed an equation for prediction of diffusion in supercritical fluids, which is based on the rough hard sphere theory.

  9. Destruction of energetic materials by supercritical water oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Beulow, S.J.; Dyer, R.B.; Harradine, D.M.; Robinson, J.M.; Oldenborg, R.C.; Funk, K.A.; McInroy, R.E.; Sanchez, J.A.; Spontarelli, T.

    1993-10-01

    Supercritical water oxidation is a relatively low-temperature process that can give high destruction efficiencies for a variety of hazardous chemical wastes. Results are presented examining the destruction of high explosives and propellants in supercritical water and the use of low temperature, low pressure hydrolysis as a pretreatment process. Reactions of cyclotrimethylene trinitramine (RDX), cyclotetramethylene tetranitramine (HMX), nitroguanidine (NQ), pentaerythritol tetranitrate (PETN), and 2,4,6-trinitrotoluene (TNT) are examined in a flow reactor operated at temperatures between 400{degrees}C and 650{degrees}C. Explosives are introduced into the reactor at concentrations below the solubility limits. For each of the compounds, over 99.9% is destroyed in less than 30 seconds at temperatures above 600{degrees}C. The reactions produce primarily N{sub 2}, N{sub 2}O,CO{sub 2}, and some nitrate and nitrite ions. The distribution of reaction products depends on reactor pressure, temperature, and oxidizer concentration. Kinetics studies of the reactions of nitrate and nitrite ions with various reducing reagents in supercritical water show that they can be rapidly and completely destroyed at temperatures above 525{degrees}C. The use of slurries and hydrolysis to introduce high concentrations of explosives into a supercritical water reactor is examined. For some compounds the rate of reaction depends on particle size. The hydrolysis of explosives at low temperatures (<100{degrees}C) and low pressures (<1 atm) under basic conditions produces water soluble, non-explosive products which are easily destroyed by supercritical water oxidation. Large pieces of explosives (13 cm diameter) have been successfully hydrolyzed. The rate, extent, and products of the hydrolysis depend on the type and concentration of base. Results from the base hydrolysis of triple base propellant M31A1E1 and the subsequent supercritical water oxidation of the hydrolysis products are presented.

  10. 超超临界机组锅炉热力计算及改造%Thermodynamic calculation for an ultra supercritical boiler and its application

    Institute of Scientific and Technical Information of China (English)

    蒋晓锋

    2014-01-01

    受外循环影响,超超临界机组锅炉有多种热力计算流程。运用3种不同的锅炉热力计算流程分析了A电厂锅炉的再热器欠温问题,提出了末级再热器改造方案。改造后,再热蒸汽温度明显升高,末级再热器工质升温幅度由76℃提高到98℃,弥补了炉膛出口温度低于设计值引起的末级再热器换热损失。%By taking a boiler in power plant A as an example,thermodynamic calculation process of the ultra supercritical boilers was analyzed.Affected by the external circulation,the ultra supercritical boilers have a variety of calculation processes.Three calculation processes were employed to investigate the insufficient reheater steam temperature of the boiler,and a transformation scheme for the final reheater was put for-ward.Check calculation for performance parameters of the retrofitted boiler was carried out,under three conditions with different gas components.The results show that,after the modification,the reheater steam increased dramatically and the temperature rise of the reheater working fluid increased from 76 ℃ to 98 ℃. This transformation scheme compensates the heat transfer loss in the final reheater caused by low furnace outlet temperature.

  11. INFLUENCE OF STEAM EXPLOSION ON THECRYSTALLINITY OF CELLULOSE FIBER

    OpenAIRE

    Jacquet, Nicolas; Vanderghem, Caroline; Danthine, Sabine; Blecker, Christophe; Richel, Aurore

    2014-01-01

    The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct stages: vapocracking and explosive decompression. The treatment intensities is determined by a severity factor, established by a correlation between temperature process and retention time. The results show that steam explosion treatment has an impact on the crystallinity properties of pure ce...

  12. Steam reforming of light oxygenates

    DEFF Research Database (Denmark)

    Trane-Restrup, Rasmus; Resasco, Daniel E; Jensen, Anker Degn

    2013-01-01

    Steam reforming (SR) of ethanol, acetic acid, acetone, acetol, 1-propanol, and propanal has been investigated over Ni/MgAl2O4 at temperatures between 400 and 700 degrees C and at a steam-to-carbon-ratio (S/C) of 6. The yield of H-2 and conversion increased with temperature, while the yield of by-products...... decreased with temperature in the SR of the investigated compounds. The yield of H2 approached the thermodynamic limit at the highest temperatures investigated. No significant differences in conversion as a function of temperature among the different model compounds were observed. However, the product...... distribution depended on the model compound, and C-3-oxygenates produced a larger fraction of by-products compared to C-2-oxygenates. Temperatures of 600 degrees C or above were generally needed to minimize the fraction of by-products and obtain a syngas containing mainly CO, CO2, H-2, and H2O with only traces...

  13. Safety Picks up "STEAM"

    Science.gov (United States)

    Roy, Ken

    2016-01-01

    This column shares safety information for the classroom. STEAM subjects--science, technology, engineering, art, and mathematics--are essential for fostering students' 21st-century skills. STEAM promotes critical-thinking skills, including analysis, assessment, categorization, classification, interpretation, justification, and prediction, and are…

  14. Experimental investigation of a natural circulation parabolic trough collector system for medium-high temperature steam generation%自然循环槽式太阳能中高温集热系统实验研究

    Institute of Scientific and Technical Information of China (English)

    陈欢; 王红梅; 俞自涛; 胡亚才; 张良; 倪煜; 樊建人

    2012-01-01

    A 50 kW natural circulation parabolic trough collector (PTC) system for medium-high temperature steam generation was proposed. Experimental investigation of thermal performance and stability was performed under different solar irradiation and discharging steam pressure conditions. Results show that the requirement of minimum solar irradiation perpendicular to the mirror for system working steadily is 254-272 W/m2. In good irradiation condition of summer, this system can generate steam at pressure up to 0. 5 MPa stably in one day. When three days continuous heating is performed, the pressure of saturated steam generated by the system reaches to 0. 8 MPa. During the steam producing process at different pressure, there is subcooling heat transfer happening due to insufficient solar radiation and thermal losses of pipes which result in inadequate heat fluxes in heat pipe.%介绍了规模为50 kW的自然循环槽式太阳能中高温集热系统,并对系统在不同太阳辐照和排汽压力工况下的传热特性及稳定性进行了实验研究.结果表明,系统稳定运行的最低有效辐照条件为垂直镜面辐照度254~272 W/m2;在较好的辐照条件下,本系统能够实现当天0.5 MPa稳定排汽;在连续3d良好辐照条件下,系统产生的饱和蒸汽压力达到0.8 MPa.在不同压力工况排汽过程中,由于辐照强度较小,管道热损失偏大,热管流量和携带热量偏小,自然循环换热系统均出现了不同程度的过冷换热现象.

  15. An Isothermal Steam Expander for an Industrial Steam Supplying System

    Directory of Open Access Journals (Sweden)

    Chen-Kuang Lin

    2015-01-01

    Full Text Available Steam is an essential medium used in the industrial process. To ensure steam quality, small and middle scale boilers are often adopted. However, because a higher steam pressure (compared to the necessary steam pressure is generated, the boiler’s steam pressure will be reduced via a pressure regulator before the steam is directed through the process. Unfortunately, pressure is somewhat wasted during the reducing process. Therefore, in order to promote energy efficiency, a pressure regulator is replaced by a steam expander. With this steam expander, the pressure will be transformed into mechanical energy and extracted during the expansion process. A new type of isothermal steam expander for an industrial steam supplying system will be presented in the paper. The isothermal steam expander will improve the energy efficiency of a traditional steam expander by replacing the isentropic process with an isothermal expansion process. With this, steam condensation will decrease, energy will increase, and steam quality will be improved. Moreover, the mathematical model of the isothermal steam expander will be established by using the Schmidt theory, the same principle used to analyze Stirling engines. Consequently, by verifying the correctness of the theoretical model for the isothermal steam expander using experimental data, a prototype of 100 c.c. isothermal steam expander is constructed.

  16. Depolymerization of polyethylene terephthalate in supercritical methanol

    Science.gov (United States)

    Goto, Motonobu; Koyamoto, Hiroshi; Kodama, Akio; Hirose, Tsutomu; Nagaoka, Shoji

    2002-11-01

    The degradation of polyethylene terephthalate (PET) in supercritical methanol was investigated with the aim of developing a process for chemical recycling of waste plastics. A batch reactor was used at temperatures of 573-623 K under an estimated pressure of 20 MPa for a reaction time of 2-120 min. PET was decomposed to its monomers, dimethyl terephthalate and ethylene glycol, by methanolysis in supercritical methanol. The reaction products were analysed using size-exclusion chromatography, gas chromatography-mass spectrometry, and reversed-phase liquid chromatography. The molecular weight distribution of the products was obtained as a function of reaction time. The yields of monomer components of the decomposition products including by-products were measured. Continuous kinetics analysis was performed on the experimental data.

  17. Using supercritical fluids to refine hydrocarbons

    Science.gov (United States)

    Yarbro, Stephen Lee

    2014-11-25

    This is a method to reactively refine hydrocarbons, such as heavy oils with API gravities of less than 20.degree. and bitumen-like hydrocarbons with viscosities greater than 1000 cp at standard temperature and pressure using a selected fluid at supercritical conditions. The reaction portion of the method delivers lighter weight, more volatile hydrocarbons to an attached contacting device that operates in mixed subcritical or supercritical modes. This separates the reaction products into portions that are viable for use or sale without further conventional refining and hydro-processing techniques. This method produces valuable products with fewer processing steps, lower costs, increased worker safety due to less processing and handling, allow greater opportunity for new oil field development and subsequent positive economic impact, reduce related carbon dioxide, and wastes typical with conventional refineries.

  18. 电厂过热汽温串级系统的约束预测控制%Cascade Constrained Model Predictive Control for Power Plant Superheated Steam Temperature System

    Institute of Scientific and Technical Information of China (English)

    冯建苗; 李少远

    2011-01-01

    Power plant superheated steam temperature system is characterized by large inertia and large lag.Usually spray system is applied to form a cascade control system and cascade PID scheme is usually employed to control superheated steam temperature.The spray valve is subject to physical constraints so that actuator saturation happens because of the set point computed by the outer loop controller.The method of cascade model predictive control was applied.Constrained model predictive control(CMPC) was used to handle constraints and obtain optimal solution with system satisfying the corresponding constraints.In addition,simulation of superheated steam system was realized.%针对实际电厂过热汽温系统中减温水阀门受到物理约束限制,外环控制器计算的设定值造成执行机构饱和从而影响系统性能的问题,提出了串级预测控制算法,并采用约束预测控制算法进行求解,在系统约束范围内求得系统性能的优化解,对电厂过热汽温控制系统进行了仿真论证.仿真结果表明,过热汽温系统控制量能被有效控制在约束范围内,并且系统保持了良好的运行结果.

  19. Numerical simulation in steam injection process by a mechanistic approach

    Energy Technology Data Exchange (ETDEWEB)

    De Souza, J.C.Jr.; Campos, W.; Lopes, D.; Moura, L.S.S. [Petrobras, Rio de Janeiro (Brazil)

    2008-10-15

    Steam injection is a common thermal recovery method used in very viscous oil reservoirs. The method involves the injection of heat to reduce viscosity and mobilize oil. A steam generation and injection system consists primarily of a steam source, distribution lines, injection wells and a discarding tank. In order to optimize injection and improve the oil recovery factor, one must determine the parameters of steam flow such as pressure, temperature and steam quality. This study focused on developing a unified mathematical model by means of a mechanistic approach for two-phase steam flow in pipelines and wells. The hydrodynamic and heat transfer mechanistic model was implemented in a computer simulator to model the parameters of steam injection while trying to avoid the use of empirical correlations. A marching algorithm was used to determine the distribution of pressure and temperature along the pipelines and wellbores. The mathematical model for steam flow in injection systems, developed by a mechanistic approach (VapMec) performed well when the simulated values of pressures and temperatures were compared with the values measured during field tests. The newly developed VapMec model was incorporated in the LinVap-3 simulator that constitutes an engineering supporting tool for steam injection wells operated by Petrobras. 23 refs., 7 tabs., 6 figs.

  20. Oxidation behavior of Incoloy 800 under simulated supercritical water conditions

    Energy Technology Data Exchange (ETDEWEB)

    Fulger, M. [Institute for Nuclear Research Pitesti, POB 78, Campului Street, No. 1, 115400 Mioveni (Romania)], E-mail: manuela.fulger@nuclear.ro; Ohai, D.; Mihalache, M.; Pantiru, M. [Institute for Nuclear Research Pitesti, POB 78, Campului Street, No. 1, 115400 Mioveni (Romania); Malinovschi, V. [University of Pitesti, Research Center for Advanced Materials, Targul din Vale Street, No. 1, 110040 Pitesti (Romania)

    2009-03-31

    For a correct design of supercritical water-cooled reactor (SCWR) components, data regarding the behavior of candidate materials in supercritical water are necessary. Corrosion has been identified as a critical problem because the high temperature and the oxidative nature of supercritical water may accelerate the corrosion kinetics. The goal of this paper is to investigate the oxidation behavior of Incoloy 800 exposed in autoclaves under supercritical water conditions for up to 1440 h. The exposure conditions (thermal deaerated water, temperatures of 723, 773, 823 and 873 K and a pressure of 25 MPa) have been selected as relevant for a supercritical power plant concept. To investigate the structural changes of the oxide films, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX) and electrochemical impedance spectroscopy (EIS) analyses were used. Results show changes in the oxides chemical composition, microstructure and thickness versus testing conditions (pressure, temperature and time). The oxide films are composed of two layers: an outer layer enriched in Fe oxide and an inner layer enriched in Cr and Ni oxides corresponding to small cavities supposedly due to internal oxidation.

  1. Boxberg - a new benchmark for high efficiency steam turbines

    Energy Technology Data Exchange (ETDEWEB)

    Hoffstadt, U.; Klauke, U.; Hinz, H. [Siemens Power Generation (Germany)

    2001-07-01

    One of the primary tasks associated with the development of modern power plant facilities is to improve the economy of operation, while at the same time reducing environmental pollution. In addition to investigations focused on supercritical steam conditions, Siemens Power generation has made enormous efforts to improve the overall efficiency by decreasing the steam flow energy losses of each steam turbine component: optimization of the admission and exhaust geometries; fully three-dimensional blading profiles; reduction of the seal-steam losses; high reliability, availability and safety of operation; optimization of the efficiency/cost-relations. As a result of these efforts the 907 MW power plant Boxberg was handed over to the customer Vereinigte Energiewerke AG recently. With a thermal gross-efficiency of 48,65% the steam turbine represents a milestone for lignite-fired cogeneration units in the history of modern turbine technology. In conjunction with the presentation of the special turbine features and its optimised fluid dynamic components, the results of assembly, commissioning and acceptance testing will be a key issue in the proposed paper. 14 overheads/slides.

  2. Low-temperature Waste Heat Powered Supercritical Thermal Power Generation Cycle Using Low-boiling Point Fluids%低温余热驱动的低沸点工质超临界动力循环

    Institute of Scientific and Technical Information of China (English)

    王辉涛; 王华; 黄晓艳

    2009-01-01

    In order to improve the performance of the thermal power generation cycle driven by low-temperature waste heat, the system should be constructed to make the temnperature of the heated working fluid match the changing temperature of the fluid carrying waste heat, the supercritical Rankine cycle using organic fluid HFC125 as the working fluid is proved to be the best promising system driven by waste heat. The energy efficiency method should be used to evaluate the overall performance of the cyde.%低温余热动力回收热动循环应与余热流的变温特性很好地匹配才能获得较高的转化效率,采用低沸点有机工质HFC125实现超临界动力循环,能很好地逼近变温热源下的理想循环,从而获得较好的效果.采用效率来评价余热回收动力循环时,可以得到相对全面的结论.

  3. Lambda-type sharp rise in the widths of Raman and infra-red line shape near the Widom line in super-critical water above its gas-liquid critical temperature

    CERN Document Server

    Samanta, Tuhin

    2016-01-01

    A lambda-type divergent rise of Raman linewidth of liquid nitrogen near its critical temperature has been a subject of many discussions in the past[1-5]. Here we explore the possibility of such an anomaly in infra-red and Raman spectroscopy of super-critical water (SCW) by varying the density across the Widom line just above its critical temperature. Vibrational phase relaxation is expected to be a sensitive probe of fluid dynamics. We carry out computer simulations of two different model potentials (SPC/E and TIP4P/2005) to obtain the necessary time correlation functions. An additional feature of this work is a quantum chemical calculation of the anharmonicity parameter that largely controls frequency fluctuations. We find a sharp rise in the vibrational relaxation rate (or the line widths) for both the models as we travel across the Widom line. The rise is noticeably less sharp in water than in nitrogen. We attribute this difference to the faster relaxation rate in water. We demonstrate that the anomalous r...

  4. Optimization of power-cycle arrangements for Supercritical Water cooled Reactors (SCWRs)

    Science.gov (United States)

    Lizon-A-Lugrin, Laure

    The world energy demand is continuously rising due to the increase of both the world population and the standard of life quality. Further, to assure both a healthy world economy as well as adequate social standards, in a relatively short term, new energy-conversion technologies are mandatory. Within this framework, a Generation IV International Forum (GIF) was established by the participation of 10 countries to collaborate for developing nuclear power reactors that will replace the present technology by 2030. The main goals of these nuclear-power reactors are: economic competitiveness, sustainability, safety, reliability and resistance to proliferation. As a member of the GIF, Canada has decided to orient its efforts towards the design of a CANDU-type Super Critical Water-cooled Reactor (SCWR). Such a system must run at a coolant outlet temperature of about 625°C and at a pressure of 25 MPa. It is obvious that at such conditions the overall efficiency of this kind of Nuclear Power Plant (NPP) will compete with actual supercritical water-power boilers. In addition, from a heat-transfer viewpoint, the use of a supercritical fluid allows the limitation imposed by Critical Heat Flux (CHF) conditions, which characterize actual technologies, to be removed. Furthermore, it will be also possible to use direct thermodynamic cycles where the supercritical fluid expands right away in a turbine without the necessity of using intermediate steam generators and/or separators. This work presents several thermodynamic cycles that could be appropriate to run SCWR power plants. Improving both thermal efficiency and mechanical power constitutes a multi-objective optimization problem and requires specific tools. To this aim, an efficient and robust evolutionary algorithm, based on genetic algorithm, is used and coupled to an appropriate power plant thermodynamic simulation model. The results provide numerous combinations to achieve a thermal efficiency higher than 50% with a

  5. Micronutrient and protein-fortified whole grain puffed rice made by supercritical fluid extrusion.

    Science.gov (United States)

    Paraman, Ilankovan; Wagner, Michael E; Rizvi, Syed S H

    2012-11-07

    Supercritical fluid extrusion (SCFX) was used to produce shelf-stable puffed rice fortified with protein, dietary fiber, and micronutrients. Product ingredients and process parameters were evaluated for end-product nutritional and textural qualities. Supercritical carbon dioxide (SC-CO(2)) served as a viscosity-lowering plasticizer and blowing agent during the process, which has been shown to produce expanded products with good textural qualities at lower temperatures (~100 °C) than conventional steam-based extrusion (130-180 °C). The fortified puffed rice contained 8% dietary fiber, 21.5% protein, and iron, zinc, and vitamins A and C at their recommended daily values in 100 g of product. The SCFX process allowed for the complete retention of all added minerals, 55-58% retention of vitamin A, and 64-76% retention of vitamin C. All essential amino acids including lysine were retained at exceptionally high levels (98.6%), and no losses were observed due to Maillard reaction or oxidation. All of the essential amino acid contents were equal to the reference protein recommended by FAO/WHO. Soy protein fortification improved the total amount of protein in the final rice products and provided a complementary amino acid profile to that of rice; the lysine content improved from 35 to 60 mg/protein, making the end product an excellent source of complete protein. Thus, SC-CO(2)-assisted extrusion is an effective process-based approach to produce cereal grain-based, low-moisture (5-8%) expanded products fortified with protein and any cocktail of micronutrients, without compromising the end-product sensory or nutritional qualities. These products are ideally suited for consumption as breakfast cereals, snack foods, and as part of nutrition bars for school lunch programs. The balanced nutritional profile and use of staple crop byproducts such as broken rice makes these expanded crisps unique to the marketplace.

  6. SOLID PHASE TRANSITION OF SYNDIOTACTIC POLYSTYRENE IN SUPERCRITICAL CO2

    Institute of Scientific and Technical Information of China (English)

    Yu-ying Li; Jia-song He

    2002-01-01

    Solid phase transition of the a form crystals to the β form crystals in syndiotactic polystyrene (sPS) samples has occurred in supercritical CO2. This transformation is different from those detected under other conditions. The effects of some factors (e.g. time, temperature, and pressure) on the solid phase transformation of sPS in supercritical CO2 were analyzed in detail. Experimental results show that longer time, higher temperature or higher pressure favors the transformation of the α form crystals to the β form crystals.

  7. Heat treatment of scallop adductor muscle using superheated steam.

    Science.gov (United States)

    Abe, T; Miyashita, K

    2007-08-01

    Scallop (Patinopecten yessoensis) adductor muscles were heated using superheated steam (150 and 200 degrees C), boiling (98 degrees C), and normal steaming (95 degrees C). The amounts of amino acids, water-soluble peptides, and nucleotides, expressed as extractive nitrogen in scallop products, are very important elements of quality and taste. After 15-min heating of scallop muscles with normal steaming and boiling, respective losses of 50% and 64% of the extractive nitrogen were observed. However, most extractive nitrogen (> 86%) remained in the scallop muscles treated with superheated steam at 150 and 200 degrees C. Protective effects of superheated steam against elution loss of nitrogen compounds were also observed in amino acid analyses of the heated products. The scallop-muscle surface temperature during treatment with superheated steam increased more quickly than that with normal steaming and boiling. The rapid water loss and the surface protein denaturation engendered formation of a 30-mum-thick film covering the surface, which prevented extractive nitrogen loss from internal tissues. Superheated steam treatment at 200 degrees C caused browning, surface shrinkage, and 47% weight loss. In marked contrast, the appearance and the weight loss of sample treated at 150 degrees C were almost the same as those of normal steaming and boiling-treated samples. These results suggested that superheated steaming at 150 degrees C is an optimal heat treatment of scallop adductor muscles.

  8. Precipitation of fluticasone propionate microparticles using supercritical antisolvent

    Directory of Open Access Journals (Sweden)

    A Vatanara

    2009-03-01

    Full Text Available ABSTRACT Background: The ability of supercritical fluids (SCFs, such as carbon dioxide, to dissolve and expand or extract organic solvents and as result lower their solvation power, makes it possible the use of SCFs for the precipitation of solids from organic solutions. The process could be the injection of a solution of the substrate in an organic solvent into a vessel which is swept by a supercritical fluid. The aim of this study was to ascertain the feasibility of supercritical processing to prepare different particulate forms of fluticasone propionate (FP, and to evaluate the influence of different liquid solvents and precipitation temperatures on the morphology, size and crystal habit of particles. Method: The solution of FP in organic solvents, was precipitated by supercritical carbon dioxide (SCCO2 at two pressure and temperature levels. Effects of process parameters on the physicochemical characteristics of harvested microparticles were evaluated. Results: Particle formation was observed only at the lower selected pressure, whilst at the higher pressure, no precipitation of particles was occurred due to dissolution of FP in supercritical antisolvent. The micrographs of the produced particles showed different morphologies for FP obtained from different conditions. The results of thermal analysis of the resulted particles showed that changes in the processing conditions didn't influence thermal behavior of the precipitated particles. Evaluation of the effect of temperature on the size distribution of particles showed that increase in the temperature from 40 oC to 50 oC, resulted in reduction of the mean particle size from about 30 µm to about 12 μm. ‍Conclusion: From the results of this study it may be concluded that, processing of FP by supercritical antisolvent could be an approach for production of diverse forms of the drug and drastic changes in the physical characteristics of microparticles could be achieved by changing the

  9. Ukraine Steam Partnership

    Energy Technology Data Exchange (ETDEWEB)

    Gurvinder Singh

    2000-02-15

    The Ukraine Steam Partnership program is designed to implement energy efficiency improvements in industrial steam systems. These improvements are to be made by the private plants and local government departments responsible for generation and delivery of energy to end-users. One of the activities planned under this program was to provide a two-day training workshop on industrial steam systems focusing on energy efficiency issues related to the generation, distribution, and consumption of steam. The workshop was geared towards plant managers, who are not only technically oriented, but are also key decision makers in their respective companies. The Agency for Rational Energy Use and Ecology (ARENA-ECO), a non-governmental, not-for-profit organization founded to promote energy efficiency and environmental protection in Ukraine, in conjunction with the Alliance staff in Kiev sent out invitations to potential participants in all the regions of Ukraine. The purpose of this report is the describe the proceedings from the workshop and provide recommendations from the workshop's roundtable discussion. The workshop was broken down into two main areas: (1) Energy efficient boiler house steam generation; and Energy efficient steam distribution and consumption. The workshop also covered the following topics: (1) Ukrainian boilers; (2) Water treatment systems; (3) A profile of UKRESCO (Ukrainian Energy Services Company); (4) Turbine expanders and electricity generation; (5) Enterprise energy audit basics; and (6) Experience of steam use in Donetsk oblast.

  10. Thermodynamic behaviour of supercritical matter.

    Science.gov (United States)

    Bolmatov, Dima; Brazhkin, V V; Trachenko, K

    2013-01-01

    Since their discovery in 1822, supercritical fluids have been of enduring interest and have started to be deployed in many important applications. Theoretical understanding of the supercritical state is lacking and is seen to limit further industrial deployment. Here we study thermodynamic properties of the supercritical state and discover that specific heat shows a crossover between two different regimes, an unexpected result in view of currently perceived homogeneity of supercritical state in terms of physical properties. We subsequently formulate a theory of system thermodynamics above the crossover, and find good agreement between calculated and experimental specific heat with no free-fitting parameters. In this theory, energy and heat capacity are governed by the minimal length of the longitudinal mode in the system only, and do not explicitly depend on system-specific structure and interactions. We derive a power law and analyse supercritical scaling exponents in the system above the Frenkel line.

  11. Gasification Mechanism of Carbon with Supercritical Water at Very High Pressures: Effects on H2 Production.

    Science.gov (United States)

    Martin-Sanchez, Nicolas; Salvador, Francisco; Sanchez-Montero, M Jesus; Izquierdo, Carmen

    2014-08-07

    The scarce data concerning the gasification of carbonaceous solids with supercritical water (SCW) suggest the great potential of this method to produce a valuable green fuel such as H2. However, the extraordinary properties of SCW have not been properly applied to H2 production because the mechanism that governs gasification under these conditions remains unclear. Here, we present a study in which this reaction is explored within the largest pressure range ever assayed in this field, from 1 to 1000 bar. The amplitude of the experimental conditions investigated highlights the various pathways that govern gasification with steam and SCW. Under supercritical conditions, the clusters formed around the superficial groups of the solid reduce the energetic requirements for gasification and generate CO2 as a primary product of the reaction. Consequently, gasification with SCW is significantly faster than that using steam, and the produced gases are richer and more appropriate to obtain pure H2.

  12. Steam generator tube failures

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, P.E.; Shah, V.N.; Ward, L.W.; Ellison, P.G.

    1996-04-01

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service.

  13. Thermoelastic steam turbine rotor control based on neural network

    Science.gov (United States)

    Rzadkowski, Romuald; Dominiczak, Krzysztof; Radulski, Wojciech; Szczepanik, R.

    2015-12-01

    Considered here are Nonlinear Auto-Regressive neural networks with eXogenous inputs (NARX) as a mathematical model of a steam turbine rotor for controlling steam turbine stress on-line. In order to obtain neural networks that locate critical stress and temperature points in the steam turbine during transient states, an FE rotor model was built. This model was used to train the neural networks on the basis of steam turbine transient operating data. The training included nonlinearity related to steam turbine expansion, heat exchange and rotor material properties during transients. Simultaneous neural networks are algorithms which can be implemented on PLC controllers. This allows for the application neural networks to control steam turbine stress in industrial power plants.

  14. Molecular Dynamics Investigation of Benzene in Supercritical Water

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Microscopic structure and diffusion properties of benzene in ambient water (298 K, 0.1 MPa) and super critical water (673-773 K, 25-35 MPa) are investigated by molecular dynamics simulation with site-site models. It is found that at the ambient condition, the water molecules surrounding a benzene molecule form a hydrogen bond network. The hydrogen bond interaction between supercritical water molecules decreases dramatically under supercritical conditions. The diffusion coefficients of both the solute molecule and solvent molecule at supercritical conditions increase by 30-180 times than those at the ambient condition. With the temperature approaching the critical temperature, the change of diffusion coefficient with pressure becomes pronounced.

  15. Quick-homogeneous Corrosion of Ti-2Al-2.5Zr Alloy in High-temperature and High-pressure Water Steam

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The corrosion behavior of Ti-2Al-2.5Zr alloy with 5 alloy contents and 5 surface states were studied in water steam at 400°C, 10.3 MPa for 72 h. The weight-increments of all samples are under 4 mg/dm2, better than Zr and Zr-alloy. α-Ti is oxidized into anatase-type TiO2 preferentially. The corrosion resistance is improved by adding Al element or pre-oxidizing treatment, the latter is more effective relatively.

  16. High-temperature process-steam application at the Southern Union Refining Company, Hobbs, New Mexico (solar energy in the oil patch). Phase I design. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1979-07-31

    Southern Union Refining Company's Famariss Energy Refinery has worked diligently with Monument Solar Corporation in the conceptual and detail design for this unique application of solar generated steam. An area closely adjacent to the refinery and fronting New Mexico State Highway No. 18 has been designated for the solar collector array. Space planned for the demonstration parabolic trough array is sufficiently large to handle an array of 25,200 square feet in size - an array more than twice the size of the 10,080 square feet proposed originally. The conceptual design, performance, safety, environmental impact, and economic analysis are described. Engineering drawings are included. (WHK)

  17. Experimental study of elliptical jet from supercritical to subcritical conditions using planar laser induced fluorescence

    Science.gov (United States)

    Muthukumaran, C. K.; Vaidyanathan, Aravind

    2015-03-01

    The study of fluid jet dynamics at supercritical conditions involves strong coupling between fluid dynamic and thermodynamic phenomena. Beyond the critical point, the liquid-vapor coexistence ceases to exist, and the fluid exists as a single phase known as supercritical fluid with its properties that are entirely different from liquids and gases. At the critical point, the liquids do not possess surface tension and latent heat of evaporation. Around the critical point, the fluid undergoes large changes in density and possesses thermodynamic anomaly like enhancement in thermal conductivity and specific heat. In the present work, the transition of the supercritical and near-critical elliptical jet into subcritical as well as supercritical environment is investigated experimentally with nitrogen and helium as the surrounding environment. Under atmospheric condition, a liquid jet injected from the elliptical orifice exhibits axis switching phenomena. As the injection temperature increases, the axis switching length also increases. Beyond the critical temperature, the axis switching is not observed. The investigation also revealed that pressure plays a major role in determining the thermodynamic transition of the elliptical jet only for the case of supercritical jet injected into subcritical chamber conditions. At larger pressures, the supercritical jet undergoes disintegration and formation of droplets in the subcritical environment is observed. However, for supercritical jet injection into supercritical environment, the gas-gas like mixing behavior is observed.

  18. Experimental study of elliptical jet from supercritical to subcritical conditions using planar laser induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Muthukumaran, C. K.; Vaidyanathan, Aravind, E-mail: aravind7@iist.ac.in [Department of Aerospace Engineering, Indian Institute of Space Science and Technology, Trivandrum, Kerala 695547 (India)

    2015-03-15

    The study of fluid jet dynamics at supercritical conditions involves strong coupling between fluid dynamic and thermodynamic phenomena. Beyond the critical point, the liquid-vapor coexistence ceases to exist, and the fluid exists as a single phase known as supercritical fluid with its properties that are entirely different from liquids and gases. At the critical point, the liquids do not possess surface tension and latent heat of evaporation. Around the critical point, the fluid undergoes large changes in density and possesses thermodynamic anomaly like enhancement in thermal conductivity and specific heat. In the present work, the transition of the supercritical and near-critical elliptical jet into subcritical as well as supercritical environment is investigated experimentally with nitrogen and helium as the surrounding environment. Under atmospheric condition, a liquid jet injected from the elliptical orifice exhibits axis switching phenomena. As the injection temperature increases, the axis switching length also increases. Beyond the critical temperature, the axis switching is not observed. The investigation also revealed that pressure plays a major role in determining the thermodynamic transition of the elliptical jet only for the case of supercritical jet injected into subcritical chamber conditions. At larger pressures, the supercritical jet undergoes disintegration and formation of droplets in the subcritical environment is observed. However, for supercritical jet injection into supercritical environment, the gas-gas like mixing behavior is observed.

  19. Thermal hydraulic studies in steam generator test facility

    Energy Technology Data Exchange (ETDEWEB)

    Vinod, V.; Suresh Kumar, V.A.; Noushad, I.B.; Ellappan, T.R.; Rajan, K.K.; Rajan, M.; Vaidyanathan, G. [Engineering Development Group Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India)

    2005-07-01

    Full text of publication follows: A 500 MWe fast breeder reactor is being constructed at Kalpakkam, India. This is a sodium cooled reactor with two primary and two secondary sodium loops with total 8 steam generators. The typical advantage of fast breeder plants is the high operating temperature of steam cycles and the high plant efficiency. To produce this high pressure and high temperature steam, once through straight tube vertical sodium heated steam generators are used. The steam is generated from the heat produced in the reactor core and being transported through primary and secondary sodium circuits. The steam generator is a 25 m high middle supported steam generator with expansion bend and 23 m heat transfer length. Steam Generator Test Facility (SGTF) constructed at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam aims at performing various tests on a 5.5 MWt steam generator. This vertically simulated test article is similar in all respects to the proposed 157 MWt steam generator module for the Prototype Fast Breeder Reactor (PFBR), with reduced number of tubes. Heat transfer performance tests are done with this 19 tube steam generator at various load conditions. Sodium circuit for the SGTF is equipped with oil fired heater as heat source and centrifugal sodium pump, to pump sodium at 105 m{sup 3}/hr flow rate. Other typical components like sodium to air heat exchanger, sodium purification system and hydrogen leak detection system is also present in the sodium circuit. High pressure steam produced in the steam generator is dumped in a condenser and recycled. Important tests planned in SGTF are the heat transfer performance test, stability test, endurance test and performance test of steam generator under various transients. The controlled operation of steam generator will be studied with possible control schemes. A steady state simulation of the steam generator is done with a mathematical model. This paper gives the details of heat transfer

  20. New ferritic steels for advanced steam plants

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, K.H; Koenig, H. [GEC ALSTHOM Energie GmbH, Nuremberg (Germany)

    1998-12-31

    During the last 15-20 years ferritic-martensitic 9-12 % chromium steels have been developed under international research programmes which permit inlet steam temperatures up to approx. 625 deg C and pressures up to about 300 bars, thus leading to improvements in thermal efficiency of around 8 % and a CO{sub 2} reduction of about 20 % versus conventional steam parameters. These new steels are already being applied in 13 European and 34 Japanese power stations with inlet steam temperature up to 610 deg C. This presentation will give an account of the content, scope and results of the research programmes and of the experience gained during the production of components which have been manufactured from the new steels. (orig.) 13 refs.

  1. Influence of austenisation temperature and hold time on grain size of type 9Cr1MoVNb ferritic-martensitic steels used in supercritical boilers; Influencia de la temperature de austenizacion y tiempo de permanencia sobre el tamano de grano en aceros ferritico-martensiticos del tipo 9Cr1MoVNb utilizados en calderas supercriticas

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez-Urrutia, I.; Gutierrez, S.; San Juan, J. M.

    2001-07-01

    The aim of the present work is to determine the influence of asutenitizing temperature holding time and heating velocity on grain size of ferritic-martensitic type 9Cr1MoVNb steels developed for Oak Ridge National Laboratories & Combustion Engineering, T91/P91 Steels (USA) and X10CrMoVNb 9.1 (Europe). The potential benefits of this materials, in term of high resistance, good ductily and oxidation resistance, weldability and in particular good high temperature creep strength, are now widely acknowledged, particulary by supercritical boilers (P=300 bar, T=550{+-}50 degree centigree). The studied steels have been produced in, high frequency induction vacum furnaces and hot-rolled. (Author) 12 refs.

  2. Analysis on Heat Transfer of Outlet Nozzle and Steam Cavity for SCWR RPV Using CFD%超临界水冷堆压力容器出口接管和蒸汽腔室热流性能数值分析

    Institute of Scientific and Technical Information of China (English)

    李玉光; 王小彬; 罗英; 杨敏; 李翔; 付强

    2013-01-01

    Based on Super-Critical Water Reactor (SCWR) conceptual configuration design, with the shell made by 508-Ⅲ low alloy forging and the outlet nozzle and steam cavity made by Inconel 690 forging, this paper focuses on the application of Computational Fluid Dynamics (CFD) in the numerical simulation of SCWR outlet nozzle and steam cavity structural design.The temperature distribution of outlet nozzle and steam cavity on the Super-Critical condition has been obtained in this study.The simulation results indicate that the maximum temperature reaches 547K at welding line between 508-Ⅲ shell and Inconel 690 nozzle, thereby it is feasible for conceptual configuration design and materials of SCWR outlet nozzle and steam cavity, and it will assist in validating the direction of configuration optimization and material selection for the design activities.%基于超临界水冷堆(SCWR)概念结构设计(简体材料为508-Ⅲ钢、出口接管和蒸汽腔室材料为Inconel 690),使用计算流体力学(CFD)方法对SCWR出口接管和蒸汽腔室结构设计进行数值分析,得到超临界工况下的压力容器出口接管和蒸汽腔室的稳态温度分布.结果表明:508-Ⅲ简体和Inconel 690出口接管焊缝处的最高温度为547 K,现有的SCWR出口接管和蒸汽腔室概念结构设计和材料具备可行性.

  3. Synthesis of biodiesel from edible and non-edible oils in supercritical alcohols and enzymatic synthesis in supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Vivek Rathore; Giridhar Madras [Indian Institute of Science, Bangalore (India). Department of Chemical Engineering

    2007-12-15

    Biodiesel is an attractive alternative fuel because it is environmentally friendly and can be synthesized from edible and non-edible oils. The synthesis of biodiesel from edible oils like palm oil and groundnut oil and from crude non-edible oils like Pongamia pinnata and Jatropha curcas was investigated in supercritical methanol and ethanol without using any catalyst from 200 to 400{sup o}C at 200 bar. The variables affecting the conversion during transesterification, such as molar ratio of alcohol to oil, temperature and time were investigated in supercritical methanol and ethanol. Biodiesel was also synthesized enzymatically with Novozym-435 lipase in presence of supercritical carbon dioxide. The effect of reaction variables such as temperature, molar ratio, enzyme loading and kinetics of the reaction was investigated for enzymatic synthesis in supercritical carbon dioxide. Very high conversions (>80%) were obtained within 10 min and nearly complete conversions were obtained at within 40 min for the synthesis of biodiesel in supercritical alcohols. However, conversions of only 60-70% were obtained in the enzymatic synthesis even after 8 h. 48 refs., 8 figs., 1 tab.

  4. Numerical analysis of helium-heated methane/steam reformer

    Science.gov (United States)

    Mozdzierz, M.; Brus, G.; Kimijima, S.; Szmyd, J. S.

    2016-09-01

    One of the most promising between many high temperature nuclear reactors applications is to produce hydrogen with heat gained. The simplest and the best examined method is steam reforming of methane. The fabricated hydrogen has wide range of use, for example can be electrochemically oxidized in fuel cells. However, heat management inside methane/steam reformer is extremely important because huge temperature gradients can cause catalyst deactivation. In this work the analysis of temperature field inside helium-heated methane/steam reformer is presented. The optimal system working conditions with respect to methane conversion rate are proposed.

  5. Optimizing the Heat Exchanger Network of a Steam Reforming System

    DEFF Research Database (Denmark)

    Nielsen, Mads Pagh; Korsgaard, Anders Risum; Kær, Søren Knudsen

    2004-01-01

    gas steam reformer along with gas purification reactors to generate clean hydrogen suited for a PEM stack. The temperatures in the various reactors in the fuel processing system vary from around 1000°C to the stack temperature at 80°C. Furthermore, external heating must be supplied to the endothermic...... steam reforming reaction and steam must be generated. The dependence of the temperature profiles on conversion in shift reactors for gas purification is also significant. The optimum heat integration in the system is thus imperative in order to minimize the need for hot and cold utilities. A rigorous 1D...

  6. Calculation of partial molar volume of components in supercritical ammonia synthesis system

    Institute of Scientific and Technical Information of China (English)

    Cunwen WANG; Chuanbo YU; Wen CHEN; Weiguo WANG; Yuanxin WU; Junfeng ZHANG

    2008-01-01

    The partial molar volumes of components in supercritical ammonia synthesis system are calculated in detail by the calculation formula of partial molar volume derived from the R-K equation of state under different conditions. The objectives are to comprehend phase beha-vior of components and to provide the theoretic explana-tion and guidance for probing novel processes of ammonia synthesis under supercritical conditions. The conditions of calculation are H2/N2= 3, at a concentra-tion of NH3 in synthesis gas ranging from 2% to 15%, Concentration of medium in supercritical ammonia syn-thesis system ranging from 20% to 50%, temperature ran-ging from 243 K to 699 K and pressure ranging from 0.1 MPa to 187 MPa. The results show that the ammonia synthesis system can reach supercritical state by adding a suitable supercritical medium and then controlling the reaction conditions. It is helpful for the supercritical ammonia synthesis that medium reaches supercritical state under the conditions of the corresponding total pres-sure and components near the normal temperature or near the critical temperature of medium or in the range of tem-perature of industrialized ammonia synthesis.

  7. Graphical procedure for comparing thermal death of Bacillus stearothermophilus spores in saturated and superheated steam.

    Science.gov (United States)

    SHULL, J J; ERNST, R R

    1962-09-01

    The thermal death curve of dried spores of Bacillus stearothermophilus in saturated steam was characterized by three phases: (i) a sharp initial rise in viable count; (ii) a low rate of death which gradually increased; and (iii) logarithmic death at maximal rate. The first phase was a reflection of inadequate heat activation of the spore population. The second and third phases represented the characteristic thermal death curve of the spores in saturated steam. A jacketed steam sterilizer, equipped with a system for initial evacuation of the chamber, was examined for superheat during normal operation. Measurements of spore inactivation and temperature revealed superheat in surface layers of fabrics being processed in steam at 121 C. The high temperature of the fabric surfaces was attributed to absorption of excess heat energy from superheated steam. The superheated steam was produced at the beginning of the normal sterilizing cycle by transfer of heat from the steam-heated jacket to saturated steam entering the vessel.

  8. Quantitative Calculation of the Influence of Cold End Parameters on the Steam Turbine Exhaust Temperature%冷端参数变化对汽轮机排汽温度影响的定量计算

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Based on heat transfer theory and formula for heat transfer coefficient of condenser provided by American heat exchange institute(HEI) and mathematical derivation,and reasonably simplify according to the Taylor’ s formula,get the function of changes of steam turbine cold end parameters on exhaust steam temperature, the paper analyzed the function relationship of the error and points out the application conditions.The function obtained can be used for the analysis of the necessity of cold end adjustment and transformation, and has the guiding significance for the energy saving of the cold end of the turbine.%根据传热学原理和美国传热协会( HEI)提供的凝汽器换热系数公式进行数学推导,并根据泰勒公式进行合理简化,得到汽轮机冷端各参数的变化对排汽温度影响的函数关系式,分析了函数关系式的误差并指出了应用条件。得到的函数可以用于对冷端调整和改造必要性的分析,对汽轮机冷端节能具有指导意义。

  9. Thermal Aspects of Using Alternative Nuclear Fuels in Supercritical Water-Cooled Reactors

    Science.gov (United States)

    Grande, Lisa Christine

    A SuperCritical Water-cooled Nuclear Reactor (SCWR) is a Generation IV concept currently being developed worldwide. Unique to this reactor type is the use of light-water coolant above its critical point. The current research presents a thermal-hydraulic analysis of a single fuel channel within a Pressure Tube (PT)-type SCWR with a single-reheat cycle. Since this reactor is in its early design phase many fuel-channel components are being investigated in various combinations. Analysis inputs are: steam cycle, Axial Heat Flux Profile (AHFP), fuel-bundle geometry, and thermophysical properties of reactor coolant, fuel sheath and fuel. Uniform and non-uniform AHFPs for average channel power were applied to a variety of alternative fuels (mixed oxide, thorium dioxide, uranium dicarbide, uranium nitride and uranium carbide) enclosed in an Inconel-600 43-element bundle. The results depict bulk-fluid, outer-sheath and fuel-centreline temperature profiles together with the Heat Transfer Coefficient (HTC) profiles along the heated length of fuel channel. The objective is to identify the best options in terms of fuel, sheath material and AHFPS in which the outer-sheath and fuel-centreline temperatures will be below the accepted temperature limits of 850°C and 1850°C respectively. The 43-element Inconel-600 fuel bundle is suitable for SCWR use as the sheath-temperature design limit of 850°C was maintained for all analyzed cases at average channel power. Thoria, UC2, UN and UC fuels for all AHFPs are acceptable since the maximum fuel-centreline temperature does not exceed the industry accepted limit of 1850°C. Conversely, the fuel-centreline temperature limit was exceeded for MOX at all AHFPs, and UO2 for both cosine and downstream-skewed cosine AHFPs. Therefore, fuel-bundle modifications are required for UO2 and MOX to be feasible nuclear fuels for SCWRs.

  10. Materials for advanced ultrasupercritical steam turbines

    Energy Technology Data Exchange (ETDEWEB)

    Purgert, Robert [Energy Industries Of Ohio Inc., Independence, OH (United States); Shingledecker, John [Energy Industries Of Ohio Inc., Independence, OH (United States); Saha, Deepak [Energy Industries Of Ohio Inc., Independence, OH (United States); Thangirala, Mani [Energy Industries Of Ohio Inc., Independence, OH (United States); Booras, George [Energy Industries Of Ohio Inc., Independence, OH (United States); Powers, John [Energy Industries Of Ohio Inc., Independence, OH (United States); Riley, Colin [Energy Industries Of Ohio Inc., Independence, OH (United States); Hendrix, Howard [Energy Industries Of Ohio Inc., Independence, OH (United States)

    2015-12-01

    The U.S. Department of Energy (DOE) and the Ohio Coal Development Office (OCDO) have sponsored a project aimed at identifying, evaluating, and qualifying the materials needed for the construction of the critical components of coal-fired power plants capable of operating at much higher efficiencies than the current generation of supercritical plants. This increased efficiency is expected to be achieved principally through the use of advanced ultrasupercritical (A-USC) steam conditions. A limiting factor in this can be the materials of construction for boilers and for steam turbines. The overall project goal is to assess/develop materials technology that will enable achieving turbine throttle steam conditions of 760°C (1400°F)/35MPa (5000 psi). This final technical report covers the research completed by the General Electric Company (GE) and Electric Power Research Institute (EPRI), with support from Oak Ridge National Laboratory (ORNL) and the National Energy Technology Laboratory (NETL) – Albany Research Center, to develop the A-USC steam turbine materials technology to meet the overall project goals. Specifically, this report summarizes the industrial scale-up and materials property database development for non-welded rotors (disc forgings), buckets (blades), bolting, castings (needed for casing and valve bodies), casting weld repair, and casting to pipe welding. Additionally, the report provides an engineering and economic assessment of an A-USC power plant without and with partial carbon capture and storage. This research project successfully demonstrated the materials technology at a sufficient scale and with corresponding materials property data to enable the design of an A-USC steam turbine. The key accomplishments included the development of a triple-melt and forged Haynes 282 disc for bolted rotor construction, long-term property development for Nimonic 105 for blading and bolting, successful scale-up of Haynes 282 and Nimonic 263 castings using

  11. Reaction kinetics of cellulose hydrolysis in subcritical and supercritical water

    Science.gov (United States)

    Olanrewaju, Kazeem Bode

    The uncertainties in the continuous supply of fossil fuels from the crisis-ridden oil-rich region of the world is fast shifting focus on the need to utilize cellulosic biomass and develop more efficient technologies for its conversion to fuels and chemicals. One such technology is the rapid degradation of cellulose in supercritical water without the need for an enzyme or inorganic catalyst such as acid. This project focused on the study of reaction kinetics of cellulose hydrolysis in subcritical and supercritical water. Cellulose reactions at hydrothermal conditions can proceed via the homogeneous route involving dissolution and hydrolysis or the heterogeneous path of surface hydrolysis. The work is divided into three main parts. First, the detailed kinetic analysis of cellulose reactions in micro- and tubular reactors was conducted. Reaction kinetics models were applied, and kinetics parameters at both subcritical and supercritical conditions were evaluated. The second major task was the evaluation of yields of water soluble hydrolysates obtained from the hydrolysis of cellulose and starch in hydrothermal reactors. Lastly, changes in molecular weight distribution due to hydrothermolytic degradation of cellulose were investigated. These changes were also simulated based on different modes of scission, and the pattern generated from simulation was compared with the distribution pattern from experiments. For a better understanding of the reaction kinetics of cellulose in subcritical and supercritical water, a series of reactions was conducted in the microreactor. Hydrolysis of cellulose was performed at subcritical temperatures ranging from 270 to 340 °C (tau = 0.40--0.88 s). For the dissolution of cellulose, the reaction was conducted at supercritical temperatures ranging from 375 to 395 °C (tau = 0.27--0.44 s). The operating pressure for the reactions at both subcritical and supercritical conditions was 5000 psig. The results show that the rate-limiting step in

  12. Distributed parameter modeling and thermal analysis of a spiral water wall in a supercritical boiler

    Directory of Open Access Journals (Sweden)

    Zheng Shu

    2013-01-01

    Full Text Available In this paper, a distributed parameter model for the evaporation system of a supercritical spiral water wall boiler is developed based on a 3-D temperature field. The mathematical method is formulated for predicting the heat flux and the metal-surface temperature. The results show that the influence of the heat flux distribution is more obvious than that of the heat transfer coefficient distribution in the spiral water wall tube, and the peak of the heat transfer coefficient decreases with an increment of supercritical pressure. This distributed parameter model can be used for a 600 MW supercritical-pressure power plant.

  13. Supercritical Extraction of Lycopene from Tomato Industrial Wastes with Ethane

    Directory of Open Access Journals (Sweden)

    Rui L. Mendes

    2012-07-01

    Full Text Available Supercritical fluid extraction of all-E-lycopene from tomato industrial wastes (mixture of skins and seeds was carried out in a semi-continuous flow apparatus using ethane as supercritical solvent. The effect of pressure, temperature, feed particle size, solvent superficial velocity and matrix initial composition was evaluated. Moreover, the yield of the extraction was compared with that obtained with other supercritical solvents (supercritical CO2 and a near critical mixture of ethane and propane. The recovery of all-E-lycopene increased with pressure, decreased with the increase of the particle size in the initial stages of the extraction and was not practically affected by the solvent superficial velocity. The effect of the temperature was more complex. When the temperature increased from 40 to 60 °C the recovery of all-E-lycopene increased from 80 to 90%. However, for a further increase to 80 °C, the recovery remained almost the same, indicating that some E-Z isomerization could have occurred, as well as some degradation of lycopene. The recovery of all-E-lycopene was almost the same for feed samples with different all-E-lycopene content. Furthermore, when a batch with a higher all-E-lycopene content was used, supercritical ethane and a near critical mixture of ethane and propane showed to be better solvents than supercritical CO2 leading to a faster extraction with a higher recovery of the carotenoid.

  14. Supercritical fluid (SCF) technologies: Assessment of applicability to installation restoration processes

    Science.gov (United States)

    1994-03-01

    USAEC has conducted an evaluation of supercritical fluid (SCF) technologies for their applicability to treatment of explosives, chlorinated hydrocarbons, and metals in soils, water, and/or waste sludge media. Off-specification explosives and propellants that have traditionally been open burned or openly detonated were also examined. Supercritical fluids are substances which have been heated and compressed to above their critical temperatures and pressures and which possess unique transport and mass transfer properties. Supercritical fluid extraction (SFE) uses the solvating properties of supercritical fluids to extract one or more organic components from a mixture into a supercritical solvent (commonly CO2). The concentrated extract stream may then be recycled, reclaimed, or destroyed by other methods.

  15. 利用高温铜渣余热进行生物质水蒸气汽化的热力学分析%Thermodynamic Analysis on Biomass Steam Gasification Using High-temperature Copper Slag Waste Heat

    Institute of Scientific and Technical Information of China (English)

    李娟琴; 胡建杭; 王华; 邓双辉; 胡威

    2013-01-01

    基于平衡常数法建立生物质水蒸气汽化的热力学平衡模型.模型计算结果表明:生物质水蒸气汽化产气组分趋于稳定的汽化条件为845~950℃、S/B(水蒸气质量与生物质质量之比)为1.5~2.0(g/g),900℃、S/B为1.64时合成气(CO+H2)产量最高,为73.15%.利用高温铜渣显热作为生物质水蒸气汽化吸热反应的外热源,计算不同汽化温度下铜渣的热焓和余热利用率.计算结果表明:汽化温度在720~950℃范围内,铜渣余热利用率为25.28%~60.04%;最优汽化工况下,铜渣余热利用率为31.66%,系统能量转化率高达48%.%A thermodynamic equilibrium model of biomass steam gasification was established based on equilibrium constant method. The calculated results show that biomass steam gasification gas are stable for 845 — 950℃ and S/B of 1. 5-2. 0(g/g) and the highest syngas (CO+ H2) yield is 73. 15% for 900 °C and S/B= 1. 64 . It was calculated that enthalpy of copper slag and sensible heat utilization efficiency of copper slag on different gasification temperature using the sensible heat of high temperature copper slag as the heat source of biomass steam gasification. The calculated results show that waste heat utilization efficiency of copper slag is 25. 28%—60. 04% within the gasification temperature range of 720 — 950 ℃ and waste heat utilization efficiency of copper slag is 31. 66% and system energy efficiency is 48% on optimal condition.

  16. Cryogenic Cooling System for Zero-Venting Storage of Supercritical Air Packs Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Supercritical air at cryogenic temperature is an attractive source of breathing air because of its very high density and low pressure. However, heat leak into the...

  17. Cryogenic Cooling System for Zero-Venting Storage of Supercritical Air Packs Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Supercritical air at cryogenic temperature is an attractive source of breathing air because of its very high density and low pressure. However, heat leak into the...

  18. High temperature process steam application at the Southern Union Refining Company, Hobbs, New Mexico. Solar energy in the oil patch. Final report, Phase III: operation, maintenance, and performance

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, L.E.; McGuire, D.R.

    1984-05-01

    This final report summarizes the technical reports for Phase III of this project. The third phase included the operation, maintenance, upgrade and performance reporting of a 10,080 square foot Solar Industrial Process Heat System installed at the Famariss Energy Refinery of Southern Union Refining Company near Hobbs, New Mexico. This report contains a description of the upgraded system, and a summary of the overall operation, maintenance and performance of the installed system. The results of the upgrade activities can be seen in the last two months of operational data. Steam production was significantly greater in peak flow and monthly total than at any previous time. Also monthly total cost savings was greatly improved even though natural gas costs remain much lower than originally anticipated.

  19. Effect of Ce and La additions in low temperature aluminization process by CVD-FBR on 12%Cr ferritic/martensitic steel and behaviour in steam oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, L. [Universidad Complutense de Madrid, Grupo de Investigacion de Ingenieria de Superficies y Materiales Nanoestructurados, Avenida Complutense s/n, Facultad de Ciencias Quimicas, 28040 Madrid (Spain)], E-mail: lsanche@quim.ucm.es; Bolivar, F.J. [Universidad de Antioquia, Facultad de Ingenierias, Medellin (Colombia); Hierro, M.P.; Perez, F.J. [Universidad Complutense de Madrid, Grupo de Investigacion de Ingenieria de Superficies y Materiales Nanoestructurados, Avenida Complutense s/n, Facultad de Ciencias Quimicas, 28040 Madrid (Spain)

    2008-08-15

    Two different coatings based of iron aluminide on 12% Cr ferritic-martensitic steel have been developed by CVD-FBR technique, which is modified by the introduction of Ce and La as powder in the fluidized bed. These elements change the gaseous environment, which composition is predicted by a thermodynamic approximation. Partial pressures of all gaseous precursors are drastically modified; in consequence AlCl has the highest partial pressure in the system leading to an increment of the coating thickness. Coatings are composed by (Fe, Cr){sub 2}Al{sub 5} or (Fe, Cr){sub 2}Al{sub 5} and (Fe, Cr)Al{sub 3} intermetallic phases. On the other hand, steam oxidation test at 650 deg. C was performed in order to observe improvements in the HCM12A oxidation resistant.

  20. Hot and cold water as a supercritical solvent

    Science.gov (United States)

    Fuentevilla, Daphne Anne

    This dissertation addresses the anomalous properties of water at high temperatures near the vapor-liquid critical point and at low temperatures in the supercooled liquid region. The first part of the dissertation is concerned with the concentration dependence of the critical temperature, density, and pressure of an aqueous sodium chloride solution. Because of the practical importance of an accurate knowledge of critical parameters for industrial, geochemical, and biological applications, an empirical equation for the critical locus of aqueous sodium chloride solutions was adopted in 1999 by the International Association for the Properties of Water and Steam (IAPWS) as a guideline. However, since this original Guideline on the Critical Locus of Aqueous Solutions of Sodium Chloride was developed, two new theoretical developments occurred, motivating the first part of this dissertation. Here, I present a theory-based formulation for the critical parameters of aqueous sodium chloride solutions as a proposed replacement for the empirical formulation currently in use. This formulation has been published in the International Journal of Thermophysics and recommended by the Executive Committee of IAPWS for adoption as a Revised Guideline on the Critical Locus of Aqueous Solutions of Sodium Chloride. The second part of the dissertation addresses a new concept, considering cold water as a supercritical solvent. Based on the idea of a second, liquid-liquid, critical point in supercooled water, we explore the possibility of supercooled water as a novel supercooled solvent through the thermodynamics of critical phenomena. In 2006, I published a Physical Review letter presenting a parametric scaled equation of state for supercooled-water. Further developments based on this work led to a phenomenological mean-field "two-state" model, clarifying the nature of the phase separation in a polyamorphic single-component liquid. In this dissertation, I modify this two-state model to

  1. Experimental research of heterogeneous nuclei in superheated steam

    Directory of Open Access Journals (Sweden)

    Bartoš Ondřej

    2016-01-01

    Full Text Available A mobile steam expansion chamber has been developed to investigate experimentally homogeneous and heterogeneous nucleation processes in steam, both in the laboratory and at power plants using the steam withdrawn from the steam turbine. The purpose of the device is to provide new insight into the physics of nonequilibrium wet steam formation, which is one of the factors limiting the efficiency and reliability of steam turbines. The expanded steam or a mixture of steam with a non-condensable gas rapidly expands in the expansion chamber. Due to adiabatic cooling, the temperature drops below the dew point of the steam at a given pressure. When reaching a sufficiently high supersaturation, droplets are nucleated. By tuning the supersaturation in the so-called nucleation pulse, particles of various size ranges can be activated. This fact is used in the present study to measure the aerosol particles present in the air. Homogeneous nucleation was negligible in this case. The experiment demonstrates the functionality of the device, data acquisition system and data evaluation methods.

  2. Experimental research of heterogeneous nuclei in superheated steam

    Science.gov (United States)

    Bartoš, Ondřej; Kolovratník, Michal; Šmíd, Bohuslav; Hrubý, Jan

    2016-03-01

    A mobile steam expansion chamber has been developed to investigate experimentally homogeneous and heterogeneous nucleation processes in steam, both in the laboratory and at power plants using the steam withdrawn from the steam turbine. The purpose of the device is to provide new insight into the physics of nonequilibrium wet steam formation, which is one of the factors limiting the efficiency and reliability of steam turbines. The expanded steam or a mixture of steam with a non-condensable gas rapidly expands in the expansion chamber. Due to adiabatic cooling, the temperature drops below the dew point of the steam at a given pressure. When reaching a sufficiently high supersaturation, droplets are nucleated. By tuning the supersaturation in the so-called nucleation pulse, particles of various size ranges can be activated. This fact is used in the present study to measure the aerosol particles present in the air. Homogeneous nucleation was negligible in this case. The experiment demonstrates the functionality of the device, data acquisition system and data evaluation methods.

  3. Research of Mould Temperature Control System for Heating the Mold Cavity Directly by Steam%蒸汽直接加热模具型腔的温度控制系统的研究

    Institute of Scientific and Technical Information of China (English)

    凌中水; 余春晖; 柴金龙; 彭友; 林国勇; 郑建平; 李春波; 潘莹; 梁业兴; 黄虹宾

    2012-01-01

    注塑件的表面质量关系到注塑件的后续加工及产品寿命,为了消除注塑件表面的缺陷与变形,提出了蒸汽直接加热模具型腔的模具温度控制原理,并研制出了相应的高光模具温度控制设备。该设备由高温水蒸气和高温干空气制备两大系统构成。其工作过程为:首先将经过去除杂质和离子的高温水蒸汽通入模腔,并将模面加热到设定温度,然后将高温干空气通入模腔,吹除模腔中的残余冷凝水。通过可编程序控制器实现对高温水蒸汽和高温干空气通入模腔的先后顺序与通入时间进行精确控制,最后使模面达到注塑要求所需的温度。该方法只加热模面及以下1 mm~2 mm厚的模芯,故极大地缩短加热时间和减少用电量;由于前后模模面均被加热,使融胶的流动性增强、融胶前锋温度和压力增高,消除了注塑件表面缺陷和变形。%The surface quality of injection molding parts relates to the followup processing and product life. In or der to eliminate the defects and distorsion of the surface, the method of mould temperature control for directly heat ing the mold cavity by steam is presented, and the corresponding equipment was developed. This device is made of two subsystemswater steam purifying system and air cleansing system, it works in the way: the high temperature and pressure steam is passed into mold cavity to heat the surface of mold cavity , then the hot air is put into the mold cavity for clearing away the residual condensed water Programmable logic controller (PLC) is used to con trol the order and duration of the steam and the hot air, until the surface temperature reach the desired temperature. In this method,the metal of mould cores are heated for depth of only 1 mm ~ 2 mm form mold surface, so it only needs the very shorter warmup time and less electricity. The flow ability of meolten plastic, the temperature and pressure of the of its front are very

  4. Study on testing condition of the glass transition temperature of steamed bread%基于动态机械分析仪的馒头玻璃化转变温度测定条件的研究

    Institute of Scientific and Technical Information of China (English)

    宋莲军; 邓玲

    2012-01-01

    食品的玻璃化转变温度是控制食品质量和稳定性的关键.食品在玻璃化转变温度下进行保存,可最大限度保存其原有色、香、味、形及营养成分,从而延长食品保存期,提高食品保存过程中质量.基于此,研究用动态机械分析仪(DMA)对馒头的玻璃化转变温度进行了测定.结果表明:在不同测定条件下得到的馒头玻璃化转变温度不同.在振幅变化,其他测定条件不变时,馒头的玻璃化转变温度随振幅的增大而减小;在温度变化速率改变,其他测定条件不变时,馒头的玻璃化转变温度随温度变化速率的增大而增大.综合得出在振幅20μm,温度变化速率2℃/min下测得的馒头玻璃化转变温度较客观准确.因此,最佳测定是其他条件不变,振幅20μm,温度变化速率2℃/min.%The glass transition temperature of food was the key to control food quality and stability. The food was preserved at the glass transition temperature, which could maximize preservation of its original color, fragrance, taste, shape and nutrition, extend shelf life, and improve the quality in food preservation process. Based on this, the glass transition temperature of steamed bread by dynamic mechanical analyzer (DMA) were determined. The results showed that: in different measurement conditions, the glass transition temperatures of steamed bread were different; when the amplitude varied but other conditions unchanged, the glass transition temperature decreased with the amplitude increasing; when the temperature changing rate varied but the other conditions unchanged, the glass transition temperature increased with the rate increasing. It was find that glass transition temperature of steamed bread measured in the amplitude of 20 μm and temperature changing rate of 2°C/min was objective and accurate. Therefore, the optimum determination conditions were as: the amplitude of 20 μm, temperature changing rate of 2°C/min and the other

  5. AN INTERIM THERMODYNAMIC PROPERTY FORMULATION FOR SUPERCRITICAL n-HEXANE

    Directory of Open Access Journals (Sweden)

    Azzedine Abbaci

    2010-07-01

    Full Text Available Accurate information on the thermodynamic properties of supercritical fluids is highly sought for the chemical technology, especially, supercritical extraction technology. The thermodynamic properties of fluids near the critical region are strongly affected by the presence of fluctuations and therefore, can not be described by conventional equation. We have investigated an interim formulation for the behavior of the thermodynamic properties of n-hexane in the vicinity of the critical region. For this reason we have used the so-called “crossover model” to describe the thermodynamic properties of n-hexane in a wide range of temperatures and densities around the critical point.

  6. Solubilities of triolein in supercritical CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, M.A.; Bernardo-Gil, M.G. [Instituto Superior Tecnico, Lisboa (Portugal). Dept. de Engenharia Quimica

    1995-11-01

    A vegetable oil typically consists of a range of triglycerides, approximately 10% diglycerides, and a small fraction of free fatty acids and other minor constituents. The use of supercritical carbon dioxide for solvent extraction is currently the subject of numerous investigations. The solubilities of triolein in supercritical carbon dioxide were measured over a temperature range of 308--328 K and at pressures between 8 and 20 MPa by the static method. The data were correlated by the model proposed by Chrastil and the modification proposed by Adachi and Lu and Del Valle and Aguilera.

  7. Experimental study of elliptical jet from sub to supercritical conditions

    Science.gov (United States)

    Muthukumaran, C. K.; Vaidyanathan, Aravind

    2014-04-01

    The jet mixing at supercritical conditions involves fluid dynamics as well as thermodynamic phenomena. All the jet mixing studies at critical conditions to the present date have focused only on axisymmetric jets. When the liquid jet is injected into supercritical environment, the thermodynamic transition could be well understood by considering one of the important fluid properties such as surface tension since it decides the existence of distinct boundary between the liquid and gaseous phase. It is well known that an elliptical liquid jet undergoes axis-switching phenomena under atmospheric conditions due to the presence of surface tension. The experimental investigations were carried out with low speed elliptical jet under supercritical condition. Investigation of the binary component system with fluoroketone jet and N2 gas as environment shows that the surface tension force dominates for a large downstream distance, indicating delayed thermodynamic transition. The increase in pressure to critical state at supercritical temperature is found to expedite the thermodynamic transition. The ligament like structures has been observed rather than droplets for supercritical pressures. However, for the single component system with fluoroketone jet and fluoroketone environment shows that the jet disintegrates into droplets as it is subjected to the chamber conditions even for the subcritical pressures and no axis switching phenomenon is observed. For a single component system, as the pressure is increased to critical state, the liquid jet exhibits gas-gas like mixing behavior and that too without exhibiting axis-switching behavior.

  8. Experimental study of elliptical jet from sub to supercritical conditions

    Energy Technology Data Exchange (ETDEWEB)

    Muthukumaran, C. K.; Vaidyanathan, Aravind, E-mail: aravind7@iist.ac.in [Department of Aerospace Engineering, Indian Institute of Space Science and Technology, Trivandrum, Kerala 695547 (India)

    2014-04-15

    The jet mixing at supercritical conditions involves fluid dynamics as well as thermodynamic phenomena. All the jet mixing studies at critical conditions to the present date have focused only on axisymmetric jets. When the liquid jet is injected into supercritical environment, the thermodynamic transition could be well understood by considering one of the important fluid properties such as surface tension since it decides the existence of distinct boundary between the liquid and gaseous phase. It is well known that an elliptical liquid jet undergoes axis-switching phenomena under atmospheric conditions due to the presence of surface tension. The experimental investigations were carried out with low speed elliptical jet under supercritical condition. Investigation of the binary component system with fluoroketone jet and N{sub 2} gas as environment shows that the surface tension force dominates for a large downstream distance, indicating delayed thermodynamic transition. The increase in pressure to critical state at supercritical temperature is found to expedite the thermodynamic transition. The ligament like structures has been observed rather than droplets for supercritical pressures. However, for the single component system with fluoroketone jet and fluoroketone environment shows that the jet disintegrates into droplets as it is subjected to the chamber conditions even for the subcritical pressures and no axis switching phenomenon is observed. For a single component system, as the pressure is increased to critical state, the liquid jet exhibits gas-gas like mixing behavior and that too without exhibiting axis-switching behavior.

  9. Research on Nil-Ductility Transition Temperature of Steel Used for Cylinder of Industrial Steam Turbine%工业汽轮机汽缸用材无塑性转变温度的研究

    Institute of Scientific and Technical Information of China (English)

    何成; 刘中华; 周黎明; 刘京伟; 林云; 宋思远

    2016-01-01

    The issue that the temperature of test liquid required by the hydraulic test shall be higher than the nil-ductility transition temperature of test material has been expressed. The NDT temperature of steel used for the cylinder of industrial steam turbine has been examined by the drop test, and the factor influenced on NDT temperature has been analyzed as well. By adopting the advanced smelting technology and heat treatment process to strictly control P and S contents, and refining the grain, NDT temperature of steel could be reduced effectively.%针对水压试验要求试验液体温度应高于试验材料的无塑性转变温度的问题,通过落锤试验测定了工业汽轮机汽缸用材的NDT温度,并分析了影响NDT温度的因素。通过先进的冶炼技术和热加工工艺严格控制P、S含量,细化晶粒等手段,可有效降低钢材的NDT温度。

  10. Reforming of methanol and glycerol in supercritical water

    NARCIS (Netherlands)

    van Bennekom, J. G.; Venderbosch, R. H.; Assink, D.; Heeres, H. J.

    2011-01-01

    Reforming of pure glycerol, crude glycerin, and methanol (pure and in the presence of Na(2)CO(3)) in supercritical water was investigated. Continuous experiments were carried out at temperatures between 450 and 650 degrees C, residence times between 6 and 173 s, and feed concentrations of 3-20 wt%.

  11. Stability of wheat germ oil obtained by supercritical carbon dioxide ...

    African Journals Online (AJOL)

    심정은

    with 1,3-regiospecific lipase at different temperatures (40 to 70°C) to produce diglycerides and ... Key words: Supercritical carbon dioxide, wheat germ oil, ethanolysis, .... Methanol (1 mL), replacing the extract, was used as the blank. The.

  12. Extraction of heavy oil by supercritical carbon dioxide

    DEFF Research Database (Denmark)

    Rudyk, Svetlana Nikolayevna; Spirov, Pavel; Søgaard, Erik Gydesen

    2010-01-01

    The present study deals with the extraction of heavy oil by supercritical carbon dioxide at the pressure values changing from 16 to 56 MPa at the fixed value of temperature: 60oC. The amount of the recovered liquid phase of oil was calculated as a percentage of the extracted amount to the initial...

  13. Aerobic Oxidation of Methyl Vinyl Ketone in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    OUYANG,Xiao-Yue(欧阳小月); JIANG,Huan-Feng(江焕峰); CHENG,Jin-Sheng(程金生); ZHANG,Qun-Jian(张群健)

    2002-01-01

    Aerobic oxidation of methyl vinyl ketone to acetal in supercritical carbon dioxide are achieved in high conversion and high selectivity when oxygen pressure reaches 0.5MPa. The effects of cocatalysts,additive, pressure and temperature of the reaction are studied in detail.

  14. Synthesis of fatty acid starch esters in supercritical carbon dioxide

    NARCIS (Netherlands)

    Muljana, Henky; van der Knoop, Sjoerd; Keijzer, Danielle; Picchioni, Francesco; Janssen, Leon P. B. M.; Heeres, Hero J.

    2010-01-01

    This manuscript describes an exploratory study on the synthesis of fatty acid/potato starch esters using supercritical carbon dioxide (scCO(2)) as the solvent. The effects of process variables such as pressure (6-25 MPa), temperature (120-150 degrees C) and various basic catalysts and fatty acid der

  15. Biodiesel fuel from rapeseed oil as prepared in supercritical methanol

    Energy Technology Data Exchange (ETDEWEB)

    Saka, S.; Kusdiana, D. [Kyoto University, Kyoto (Japan). Dept. of Socio-Environmental Energy Science, Graduate School of Energy Science

    2001-01-01

    Transesterification reaction of rapeseed oil in supercritical methanol was investigated without using any catalyst. An experiment has been carried out in the batch-type reaction vessel preheated at 350 and 400{degree}C and at a pressure of 45-65 MPa, and with a molar ratio of 1:42 of the rapeseed oil to methanol. It was consequently demonstrated that, in a preheating temperature of 350{degree}C, 240 s of supercritical treatment of methanol was sufficient to convert the rapeseed oil to methyl esters and that, although the prepared methyl esters were basically the same as those of the common method with a basic catalyst, the yield of methyl esters by the former was found to be higher than that by the latter. In addition, it was found that this supercritical methanol process requires the shorter reaction time and simpler purification procedure because of the unused catalyst. 16 refs., 9 figs., 2 tabs.

  16. Preparation of drug delivery systems using supercritical fluid technology.

    Science.gov (United States)

    Kompella, U B; Koushik, K

    2001-01-01

    Small changes in temperature and pressure near the critical region induce dramatic changes in the density and solubility of supercritical fluids, thereby facilitating the use of environmentally benign agents such as CO2 for their solvent and antisolvent properties in processing a wide variety of materials. While supercritical fluid technologies have been in commercial use in the food and chromatography industries for several years, only recently has this technology made inroads in the formulation of drug delivery systems. This review summarizes some of the recent applications of supercritical fluid technology in the preparation of drug delivery systems. Drugs containing polymeric particles, plain drug particles, solute-containing liposomes, and inclusion complexes of drug and carrier have been formulated using this technology. Also, polymer separation using this technology is enabling the selection of a pure fraction of a polymer, thereby allowing a more precise control of drug release from polymeric delivery systems.

  17. Application of Neutron Radiography to Flow Visualization in Supercritical Water

    Science.gov (United States)

    Takenaka, N.; Sugimoto, K.; Takami, S.; Sugioka, K.; Tsukada, T.; Adschiri, T.; Saito, Y.

    Supercritical water is used in various chemical reaction processes including hydrothermal synthesis of metal oxide nano-particles, oxidation, chemical conversion of biomass and plastics. Density of the super critical water is much less than that of the sub-critical water. By using neutron radiography, Peterson et al. have studied salt precipitation processes in supercritical water and the flow pattern in a reverse-flow vessel for salt precipitation, and Balasko et al. have revealed the behaviour of supercritical water in a container. The nano-particles were made by mixing the super critical flow and the sub critical water solution. In the present study, neutron radiography was applied to the flow visualization of the super and sub critical water mixture in a T-junction made of stainless steel pipes for high pressure and temperature conditions to investigate their mixing process. Still images by a CCD camera were obtained by using the neutron radiography system at B4 port in KUR.

  18. Application of supercritical antisolvent method in drug encapsulation: a review

    Directory of Open Access Journals (Sweden)

    Kalani M

    2011-07-01

    Full Text Available Mahshid Kalani, Robiah YunusChemical and Environmental Engineering, Faculty of Engineering, University Putra Malaysia, Selangor Darul Ehsan, MalaysiaAbstract: The review focuses on the application of supercritical fluids as antisolvents in the pharmaceutical field and demonstrates the supercritical antisolvent method in the use of drug encapsulation. The main factors for choosing the solvent and biodegradable polymer to produce fine particles to ensure effective drug delivery are emphasized and the effect of polymer structure on drug encapsulation is illustrated. The review also demonstrates the drug release mechanism and polymeric controlled release system, and discusses the effects of the various conditions in the process, such as pressure, temperature, concentration, chemical compositions (organic solvents, drug, and biodegradable polymer, nozzle geometry, CO2 flow rate, and the liquid phase flow rate on particle size and its distribution.Keywords: supercritical antisolvent method, drug encapsulation, particle size, drug release mechanisms, drug delivery

  19. The latent heat of vaporization of supercritical fluids

    Science.gov (United States)

    Banuti, Daniel; Raju, Muralikrishna; Hickey, Jean-Pierre; Ihme, Matthias

    2016-11-01

    The enthalpy of vaporization is the energy required to overcome intermolecular attractive forces and to expand the fluid volume against the ambient pressure when transforming a liquid into a gas. It diminishes for rising pressure until it vanishes at the critical point. Counterintuitively, we show that a latent heat is in fact also required to heat a supercritical fluid from a liquid to a gaseous state. Unlike its subcritical counterpart, the supercritical pseudoboiling transition is spread over a finite temperature range. Thus, in addition to overcoming intermolecular attractive forces, added energy simultaneously heats the fluid. Then, considering a transition from a liquid to an ideal gas state, we demonstrate that the required enthalpy is invariant to changes in pressure for 0 intermolecular forces in the real fluid vapor during heating. At supercritical pressures, all of the transition occurs at non-equilibrium; for p -> 0 , all of the transition occurs at equilibrium.

  20. Feasibility Study of Supercritical Light Water Cooled Fast Reactors for Actinide Burning and Electric Power Production, Progress Report for Work Through September 2002, 4th Quarterly Report

    Energy Technology Data Exchange (ETDEWEB)

    Mac Donald, Philip Elsworth

    2002-09-01

    The use of light water at supercritical pressures as the coolant in a nuclear reactor offers the potential for considerable plant simplification and consequent capital and O&M cost reduction compared with current light water reactor (LWR) designs. Also, given the thermodynamic conditions of the coolant at the core outlet (i.e. temperature and pressure beyond the water critical point), very high thermal efficiencies of the power conversion cycle are possible (i.e. up to about 45%). Because no change of phase occurs in the core, the need for steam separators and dryers as well as for BWR-type re-circulation pumps is eliminated, which, for a given reactor power, results in a substantially shorter reactor vessel and smaller containment building than the current BWRs. Furthermore, in a direct cycle the steam generators are not needed. If no additional moderator is added to the fuel rod lattice, it is possible to attain fast neutron energy spectrum conditions in a supercritical water-cooled reactor (SCWR). This type of core can make use of either fertile or fertile-free fuel and retain a hard spectrum to effectively burn plutonium and minor actinides from LWR spent fuel while efficiently generating electricity. One can also add moderation and design a thermal spectrum SCWR. The Generation IV Roadmap effort has identified the thermal spectrum SCWR (followed by the fast spectrum SCWR) as one of the advanced concepts that should be developed for future use. Therefore, the work in this NERI project is addressing both types of SCWRs.

  1. Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

    Directory of Open Access Journals (Sweden)

    Balicki Adrian

    2014-06-01

    Full Text Available Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of ‘zeroemission’ technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes.

  2. Biofuel production from crude palm oil with supercritical alcohols: comparative LCA studies.

    Science.gov (United States)

    Sawangkeaw, Ruengwit; Teeravitud, Sunsanee; Piumsomboon, Pornpote; Ngamprasertsith, Somkiat

    2012-09-01

    A recent life cycle assessment (LCA) reported that biodiesel production in supercritical alcohols (SCA) produces a higher environmental load than the homogeneous catalytic process because an enormous amount of energy is required to recover excess alcohol. However, the excess alcohol could be dramatically reduced by increasing the operating temperature to 400°C; although the product would have to be considered as an alternative biofuel instead of biodiesel. A comparative LCA of the biodiesel production in two SCA at 300°C (C-SCA) and novel biofuel production in the same two SCA at 400°C (N-SCA) is presented. It was clear that the N-SCA process produces a dramatically reduced environmental load over that of the C-SCA process due to a lower amount of excess alcohol being used. The N-SCA process could be improved in terms of its environmental impact by changing from fossil fuel to biomass-based fuels for the steam generation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Supercritical fluid thermodynamics from equations of state

    Science.gov (United States)

    Giovangigli, Vincent; Matuszewski, Lionel

    2012-03-01

    Supercritical multicomponent fluid thermodynamics are often built from equations of state. We investigate mathematically such a construction of a Gibbsian thermodynamics compatible at low density with that of ideal gas mixtures starting from a pressure law. We further study the structure of chemical production rates obtained from nonequilibrium statistical thermodynamics. As a typical application, we consider the Soave-Redlich-Kwong cubic equation of state and investigate mathematically the corresponding thermodynamics. This thermodynamics is then used to study the stability of H2-O2-N2 mixtures at high pressure and low temperature as well as to illustrate the role of nonidealities in a transcritical H2-O2-N2 flame.

  4. ENGINEERING BULLETIN: SUPERCRITICAL WATER OXIDATION

    Science.gov (United States)

    This engineering bulletin presents a description and status of supercritical water oxidation technology, a summary of recent performance tests, and the current applicability of this emerging technology. This information is provided to assist remedial project managers, contractors...

  5. Low-temperature H{sub 2}S removal from steam-containing gas mixtures with ZnO for fuel cell application. 1. ZnO particles and extrudates

    Energy Technology Data Exchange (ETDEWEB)

    Ivan I. Novochinskii; Chunshan Song; Xiaoliang Ma; Xinsheng Liu; Lawrence Shore; Jordan Lampert; Robert J. Farrauto [Pennsylvania State University, University Park, PA (USA). Clean Fuels and Catalysis Program, Energy Institute and Department of Energy and Geo-Environmental Engineering

    2004-04-01

    Sulfur removal is important for a fuel cell that uses a hydrocarbon fuel, such as natural gas, liquefied petroleum gas, and gasoline, to prevent the downstream sulfur poisoning of catalysts in the fuel processor and in the fuel cell anode. Although most sulfur species are removed prior to reforming, the reducing environment of the reforming stage (such as autothermal reforming) converts residual sulfur to hydrogen sulfide (H{sub 2}S). H{sub 2}S in the reformate must be removed to ensure longevity of the catalysts in downstream processing and in the anode chamber of fuel cell systems. A unique modified ZnO sample with a different morphology has been prepared and comparatively studied together with a commercially available ZnO sample under various conditions. Extremely low H{sub 2}S outlet concentrations - as low as 20 parts per billion by volume (ppbv) - have been observed over the modified ZnO sample for extended periods of times. The sulfur-trap capacity (the amount of H{sub 2}S trapped before breakthrough) also is dependent on space velocity, temperature, steam concentration, CO{sub 2} concentration, and particle size. Higher capacity is observed at higher H{sub 2}S inlet concentration of 8 ppmv, compared to lower inlet concentrations of 1-4 ppmv. The trap capacity decreases monotonically as the temperature increases. Steam in the reformate inhibits the capture of H{sub 2}S by ZnO; it seems to shift the equilibrium of the reaction ZnO(s) + H{sub 2}S(g) {Longleftrightarrow} ZnS(s) + H{sub 2}O(g) to the left, toward ZnO and H{sub 2}S. The effect of steam seems to be reversible. Increasing the CO{sub 2} concentration in the feed up to 12 vol % decreases the capacity of ZnO for the capture of H{sub 2}S. 16 refs., 10 figs., 4 tabs.

  6. Treatment of sewage sludge in supercritical water and evaluation of the combined process of supercritical water gasification and oxidation.

    Science.gov (United States)

    Qian, Lili; Wang, Shuzhong; Xu, Donghai; Guo, Yang; Tang, Xingying; Wang, Longfei

    2015-01-01

    Influences of temperature and oxidation coefficient (n) on sewage sludge treatment in supercritical water and its corresponding reaction mechanism were studied. Moreover, the combined process of supercritical water gasification (SCWG) and supercritical water oxidation (SCWO) was also investigated. The results show that ammonia nitrogen, phenols and pyridines are main refractory intermediates. The weight of solid products at 873K and n=4 is only 3.5wt.% of the initial weight, which is lower than that after combustion. Volatile organics in solid phase have almost released at 723K and n=0. Highest yield of combustible gases was obtained at n=0, and H2 yield can reach 11.81mol/kg at 873K. Furthermore, the combination of SCWG at 723K and SCWO at 873K with a total n=1 is feasible for its good effluent quality and low operation costs.

  7. 高温电解水蒸汽制氢关键材料研究进展%Development on Key Materials for Hydrogen Production via High-Temperature Steam Electrolysis

    Institute of Scientific and Technical Information of China (English)

    任耀宇; 马景陶; 昝青峰; 林旭平; 张勇; 邓长生

    2011-01-01

    High-temperature steam electrolysis (HTSE) is an inverse process of high-temperature solid state fuel cells. The key aspect for the technology application is the materials for electrolysis cells. This review summerizes the merits of the HTSE, and presents the recent development on the HTSE, and summarizes the merits of the HTSE. Also, this review introduces the progress of the "co-electrolysis" of carbon dioxide and steam for syngas (CO+H2) production in the United States. In addition, some problems of developing the key materials are discussed. The structural optimization and development of novel material systems are proposed.%高温电解水蒸汽制氢技术是高温固体氧化物燃料电池发电的逆过程.实现这种技术的关键是电解池材料.本文综述了高温电解水蒸汽制氢技术的优点,及国内外该项技术的研究现状和发展趋势,并简要介绍了在美国用此技术进行二氧化碳、水蒸汽共电解制备合成气体(一氧化碳+氢气)的进展情况.对高温电解水蒸汽制氢技术所涉及关键材料存在的问题进行了归纳总结,并提出从优化结构和选择新材料体系两方面入手的解决办法.

  8. Modifikasi Alat Steam untuk Pembengkokan Rotan

    Directory of Open Access Journals (Sweden)

    Eustasia Sri Murwati

    2016-04-01

    distribution of steam because there are no spaces between rattans besides contact with rust stains from tube steamer. The purpose of this study was to modify steamer that is designed multi-purpose steam, can soften rattan with wet steam in a steamer tube, can also be sprayed with dry steam on the rattan surfaces. The method is carried out field survey and literature, design planning, procurement of materials, manufacturing equipment, testing equipment, finishing equipment, evaluation and reporting. The test tool with rattan variable crosssection of 2,4 cm, 2,8 cm 3,2 cm and a steaming rattan 5 minutes, 10 minutes, and 15 minutes, with boiler and steamer tube temperature 110° C, 2 bar maximum pressure (kg / cm2. Results obtained in the form of 1 unit Steam Tool For Bending Rattan consists of: Heating, Steam boiler stainless steel base material JIS G 3116-2000 standard specifications, 118 liter of volume, steam tube SUS 340 Grade, soaking tub and bending table. The trial results are best with a steaming time of 15 minutes, rattan is not broken, no cracking or not deflated, for all variable diameter. Can bend U shape rattan, Ω, semi-circular and spiral. Dry steam trials with great results at the time of spraying is greater than 20 minutes.Keywords: steamer, furniture, bending, rattan

  9. Optimization and Comparison of Direct and Indirect Supercritical Carbon Dioxide Power Plant Cycles for Nuclear Applications

    Energy Technology Data Exchange (ETDEWEB)

    Edwin A. Harvego; Michael G. McKellar

    2011-11-01

    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 both a direct and indirect supercritical CO2 Brayton Recompression cycle for different reactor outlet temperatures. The direct supercritical CO2 cycle transferred heat directly from a 600 MWt reactor to the supercritical CO2 working fluid supplied to the turbine generator at approximately 20 MPa. The indirect supercritical CO2 cycle assumed a helium-cooled Very High Temperature Reactor (VHTR), operating at a primary system pressure of approximately 7.0 MPa, delivered heat through an intermediate heat exchanger to the secondary indirect supercritical CO2 Brayton Recompression cycle, again operating at a pressure of about 20 MPa. For both the direct and indirect cycles, sensitivity calculations were performed for reactor outlet temperature

  10. Supercritical fluid technology

    Energy Technology Data Exchange (ETDEWEB)

    Penninger, J.M.L.; McHugh, M.A.; Radosz, M.; Krukonis, V.J.

    1985-01-01

    This book presents the state-of-the-art in the science and technology of supercritical fluid (scf) processing. Current research as described in the book, focuses on developments in equations of state for binary and multicomponent mixtures (including polymer solutions), solubility measurements at near-critical conditions, measurements of critical properties of binary mixtures and their correlation with equations of state. Progress in thermodynamics, coupled with advances in the design and construction of high pressure equipment, has opened up a wide avenue of commercial application (e.g. decaffeination of coffee beans, extractions of flavours and spices, purification of pharmaceutical products, separations of polymeric materials, deodorization and deacidification of vegetable oils, fractionation of fatty acids, coal liquefaction, wood delignitication, etc.)

  11. Supercritical Fluid Extraction of Palm Carotenoids

    Directory of Open Access Journals (Sweden)

    Puah C. Wei

    2005-01-01

    Full Text Available The extraction of carotenoids from crude palm oil was carried out in a dynamic (flow- through supercritical fluid extraction system. The carotenoids obtained were quantified using off-line UV-visible spectrophotometry. The effects of operating pressure and temperature, flow rate of the supercritical carbon dioxide (SC-CO2, sample size of feed used on the solubility of palm carotenoids were investigated. The results showed that the extraction of carotenoids was governed by its solubility in the SC-CO2 and can be enhanced by increasing pressure at a constant temperature or decreasing temperature at a constant pressure. Increasing the flow rate and decreasing the sample size can reduce the extraction time but do not enhance the solubility. Palm carotenoids have very low solubility in SC-CO2 in the range of 1.31 x 10-4 g kg-1 to 1.58 x 10-3 g kg-1 for the conditions investigated in this study. The experimental data obtained were compared with those published by other workers and correlated by a density-based equation as proposed by Chrastil.

  12. Methane Steam Reforming Kinetics for a Rhodium-Based Catalyst

    DEFF Research Database (Denmark)

    Jakobsen, Jon Geest; Jakobsen, M.; Chorkendorff, Ib

    2010-01-01

    Methane steam reforming is the key reaction to produce synthesis gas and hydrogen at the industrial scale. Here the kinetics of methane steam reforming over a rhodium-based catalyst is investigated in the temperature range 500-800 A degrees C and as a function of CH4, H2O and H-2 partial pressures....... The methane steam reforming reaction cannot be modeled without taking CO and H coverages into account. This is especially important at low temperatures and higher partial pressures of CO and H-2. For methane CO2 reforming experiments, it is also necessary to consider the repulsive interaction of CO...

  13. [Research of the essential oil of Plumeria rubra var. actifolia from Laos by supercritical carbon dioxide extraction].

    Science.gov (United States)

    Xiao, Xin-Yu; Cui, Long-Hai; Zhou, Xin-Xin; Wu, Yan; Ge, Fa-Huan

    2011-05-01

    The orthogonal test and the supercritical carbon dioxide fluid extraction were used for optimizing the extraction of the essential oil from Plumeria rubra var. actifolia for the first time. Compared with the steam distillation, the optimal operation parameter of extraction was as follows: extraction pressure 25 MPa, extraction temperature 45 degrees C; separator I pressure 12 MPa, separator I temperature 55 degrees C; separator II pressure 6 MPa, separator II temperature 30 degrees C. Under this condition the yield of the essential oil was 5.8927%. The components were separated and identified by GC-MS. 53 components of Plumeria rubra var. actifolia measured by SFE method were identified and determined by normalization method. The main components were 1, 6, 10-dodecatrien-3-ol, 3, 7, 11-trimethyl, benzoic acid, 2-hydroxy-, phenylmethyl ester, 1, 2-benzenedicarboxylic acid, bis(2-methylpropyl) ester,etc.. 1, 2-Benzenedicarboxylic acid, bis (2-methylpropyl) este. took up 66.11% of the total amount, and there was much difference of the results from SD method.

  14. STEAM GENERATOR GROUP PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Clark, R. A.; Lewis, M

    1985-09-01

    This report is a summary of progress in the Surry Steam Generator Group Project for 1984. Information is presented on the analysis of two baseline eddy current inspections of the generator. Round robin series of tests using standard in-service inspection techniques are described along with some preliminary results. Observations are reported of degradation found on tubing specimens removed from the generator, and on support plates characterized in-situ. Residual stresses measured on a tubing specimen are reported. Two steam generator repair demonstrations are described; one for antivibration bar replacement, and one on tube repair methods. Chemical analyses are shown for sludge samples removed from above the tube sheet.

  15. Supercritical power plant 600 MW with cryogenic oxygen plant and CCS installation

    Science.gov (United States)

    Kotowicz, Janusz; Dryjańska, Aleksandra

    2013-09-01

    This article describes a thermodynamic analysis of an oxy type power plant. The analyzed power plant consists of: 1) steam turbine for supercritical steam parameters of 600 °C/29 MPa with a capacity of 600 MW; 2) circulating fluidized bed boiler, in which brown coal with high moisture content (42.5%) is burned in the atmosphere enriched in oxygen; 3) air separation unit (ASU); 4) CO2 capture installation, where flue gases obtained in the combustion process are compressed to the pressure of 150 MPa. The circulated fluidized bed (CFB) boiler is integrated with a fuel dryer and a cryogenic air separation unit. Waste nitrogen from ASU is heated in the boiler, and then is used as a coal drying medium. In this study, the thermal efficiency of the boiler, steam cycle thermal efficiency and power demand were determined. These quantities made possible to determine the net efficiency of the test power plant.

  16. High yield hydrogen production from low CO selectivity ethanol steam reforming over modified Ni/Y 2O 3 catalysts at low temperature for fuel cell application

    Science.gov (United States)

    Sun, Jie; Luo, Dingfa; Xiao, Pu; Jigang, Li; Yu, Shanshan

    Ethanol-water mixtures were converted directly into H 2 with 67.6% yield and >98% conversion by catalytic steam reforming at 350 °C over modified Ni/Y 2O 3 catalysts heat treated at 500 °C. XRD was used to test the structure and calculate the grain sizes of the samples with different scan rates. The initial reaction kinetics of ethanol over modified and unmodified Ni/Y 2O 3 catalysts were studied by steady state reaction and a first-order reaction with respect to ethanol was found. TPD was used to analyze mechanism of ethanol desorption over Ni/Y 2O 3 catalyst. Rapid vaporization, efficiency tube reactor and catalyst were used so that homogeneous reactions producing carbon, acetaldehyde, and carbon monoxide could be minimized. And even no CO detective measured during the first 49 h reforming test on the modified catalyst Ni/Y 2O 3. This process has great potential for low cost H 2 generation in fuel cells for small portable applications where liquid fuel storage is essential and where systems must be small, simple, and robust.

  17. Nanotechnology and supercritical fluids | Hamidreza | Journal of ...

    African Journals Online (AJOL)

    Several techniques have been proposed to produce nanomaterials using ... of the supercritical based techniques applied to the production of nanoparticles materials. Keywords: Supercritical fluids; Nanoparticles; SCF technology; RESS; SAS.

  18. EFFECT OF STEAMING ON THE COLOUR CHANGE OF SOFTWOODS

    Directory of Open Access Journals (Sweden)

    Laszlo Tolvaj,

    2012-05-01

    Full Text Available The heat treatment of softwood (i.e. spruce, pine, fir, and larch may result in significant colour changes. During this study Scots pine and spruce samples were steamed and analysed for their altered hue and lightness. Treatments included: 0 to 22 days of steaming time at a temperature range of 70 to 100°C. The outcome included a variety of colours between the initial hues and brownish tint. These new colours are similar to that of aged furniture and indoor wooden structures. Consequently, properly steamed softwood may be used to repair historical artefacts and relic furniture. Besides restoration, steamed stocks are excellent sources for manufacture of periodical furniture, where the aged appearance has aesthetical value. Results however, indicated that steaming at a temperature above 90 ˚C has a bleaching effect, i.e. the coloured chemical components formed by moderate steaming may be removed. Furthermore, we observed a linear correlation between lightness and colour hue at all steaming times and temperatures.

  19. Investigation of the steam-cooled blade in a steam turbine cascade

    Institute of Scientific and Technical Information of China (English)

    Dieter Bohn; Jing Ren; Karsten Kusterer

    2007-01-01

    With the increasing demand for electricity,an efficiency improvement and thereby reduced CO2 emissions of the coal-fired plants are expected in order to reach the goals set in the Kyoto protocol.It can be achieved by a rise of the process parameters.Currently,live steam pressures and temperatures up to 300 bars and 923 K are planned as the next step.Closed circuit steam cooling of blades and vanes in modern steam turbines is a promising technology in order to establish elevated live steam temperatures in future steam turbine cycles.In this paper,a steam-cooled test vane in a cascade with external hot steam flow is analyzed numerically with the in-house code CHTflow.A parametric analysis aiming to improve the cooling effectiveness is carried out by varying the cooling mass flow ratio.The results from two investigated cases show that the steam cooling technique has a good application potential in the steam turbine.The internal part of the vane is cooled homogeneously in both cases.With the increased cooling mass flow rate,there is a significant improvement of cooling efficiency at the leading edge.The results show that the increased cooling mass flow ratio can enhance the cooling effectiveness at the leading edge.With respect to trailing edge,there is no observable improvement of cooling effectiveness with the increased cooling mass flow.This implies that due to the limited dimension at the trailing edge,the thermal stress cannot be decreased by increasing the cooling mass flow rate.Therefore,impingement-cooling configuration at the trailing edge might be a solution to overcome the critical thermal stress there.It is also observed that the performance of the cooling effective differs on pressure side and suction side.It implicates that the equilibrium of the cooling effectiveness on two sides are influenced by a coupled relationship between cooling mass flow ratio and hole geometry.In future work,optimizing the hole geometry and cooling steam supply conditions might

  20. Steam oxidation resistant coatings for steam turbine components: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Agueero, A.; Garcia de Blas, J.; Muelas, R.; Sanchez, A.; Tsipas, S. [Instituto de Tecnica Aeroespacial, Madrid (Spain). Area de Materiales

    2001-07-01

    The principal objective of the COST Action 522 is to raise the operating temperatures of both gas and steam turbines in order to increase their efficiency to reduce fuel consumption and emissions. Concerning steam turbines, the operating temperature is expected to rise from 550 C to 650 C, and the use of oxidation resistant coatings is being considered for the first time in Europe. In this preliminary work, two deposition techniques have so far been explored: slurry paints and atmospheric plasma spray (APS). Commercially available materials, known to have good oxidation resistance, were selected for both deposition techniques: one aluminium slurry and three alloyed materials for thermal spray: AlFe, FeCrAl and NiAl. The coatings were characterised by SEM-EDS and steam oxidation testing was carried out at 650 C. The preliminary findings show that some of the studied coatings may offer adequate protection. (orig.)