共查询到20条相似文献,搜索用时 31 毫秒
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《Heat Recovery Systems and CHP》1987,7(6):465-472
Use of pressurized, fluidized-bed combustion (PFBC) has given a new opportunity to use municipal refuse as fuel for combined gas and steam power cycles keeping the pollutants of sulphur and nitrogen oxides to a minimum at reduced capital cost.In combined gas and steam power cycles, the heat energy in the exhaust gases of a simple gas turbine cycle is used to generate steam in a waste-heat boiler and the generated steam is used in the steam turbine for power generation.The effects of gas turbine pressure ratio and inlet temperature on the main parameters of refuse-fired, pressurized, fluidized-bed combustion combined cycles are determined.The results indicate a maximum combined cycle thermal efficiency and work output at a possible range of optimum pressure ratios between 10 and 12 for a range of gas turbine inlet temperatures of 750–1000°C. 相似文献
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《Heat Recovery Systems and CHP》1990,10(3):187-211
In the present study a number of expressions determining the irreversible entropy generation in a rotary regenerator are presented. Adding to them formulae: (i) concerning the efficiency of a steam power plant, (ii) describing heat transfer and the pressure losses in a rotary heat exchanger, a computational model has been obtained in order to show how these irreversibilities and the efficiency of a steam power plant depend on the design parameters of a rotary regenerator. Here it was useful to assume an air cycle i-s for flue gas in a steam boiler. The numerical results are presented mainly in graph form making it possible to show the results obtained clearly and to easily draw some conclusions. By first, varying the values of the rotary regenerator matrix height, distribution factor of regenerator flow area on the hot and cold sides, total leakage factor, distribution factor of total leakage on the hot and cold ends and density of gas mass rates flowing through each side of the regenerator, the dependence of the entropy generation rates on the above parameter values is demonstrated. The direct effects of changes in values of the above parameters on a normalized energy measure or irreversibilities and the efficiency of a steam power plant are then evaluated. Having these results presented in juxtaposition, some general and practical conclusions are formulated. 相似文献
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《Heat Recovery Systems and CHP》1989,9(6):547-552
Gas turbine exhaust is usually relatively clean, especially the exhaust from natural gas turbines. The use of such gases to improve the overall thermal efficiency of a steam power plant has the advantage of reducing the cost of cleaning the equipment and reducing the maintenance costs of the heat recovery equipment used in the application.In this paper, two proposals for recovering the waste energy of the exhaust gases from a gas turbine unit, fuelled by natural gas at south Baghdad Power Plant (Iraq) are discussed. The proposals cover improvements to the thermal efficiency of a steam power plant installed near the gas turbine unit. The first proposal is to use the exhaust gases to preheat the feed water at four feed water heaters, in order to increase the power output. This arises because of the savings in the amount of steam extracted at a different level used for preheating the feed water line. The second proposal is to use the thermal energy in the exhaust gases to reheat the extracted stream, at five points at a high thermal potential, to increase the thermal gain at the preheating feed water line. This avoids the complexity associated with rejection of the extracted steam. The first roposal shows that a 1.22–14.9% saving in fuel consumption is achievable and the overall thermal efficiency of the steam power plant becomes 29–34% (at different gas turbine plant loads). The second proposal shows that a 2.3–7.35% saving in fuel consumption can be attained and the corresponding thermal efficiency will be 30.3–32%. 相似文献
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《Heat Recovery Systems and CHP》1990,10(3):255-267
Combined gas/steam turbine cycle plants have been proposed for cogeneration of electricity and process steam. Examples are combined-cycle power plants coupled with sea-water desalination, district heating plants, chemical industries, etc. In combined heat and power plants, the gas turbine exhaust heat is utilized through the use of heat recovery steam generators (HRSG's). As a result, these waste heat generators (boilers), whether fired or unfired, control the performance of the combined plant lower side (bottoming cycle). Moreover, any changes made in the HRSG operating parameters (i.e. the pinch point, approach temperature, first and second stage pressures, and mass ratios) can greatly affect the HRSG performance and will eventually affect the overall combined plant performance. This paper presents a method to predict the performance of the heat recovery steam generators (HRSG)/steam bottoming cycle combined with sea-water desalination plant at various steam and exhaust gas conditions. 相似文献
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《Heat Recovery Systems and CHP》1989,9(3):275-280
Analytical studies were conducted to investigate the thermal performance of a heat pipe heat exchanger to recover thermal energy from exhaust hot gas from a boiler, in order to replace a conventional heat recovery system (Ljungstrom) in the steam power plant. 相似文献
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Voshall R. E. Wright R. J. Liebermann R. W. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1977,5(2):110-122
A closed-cycle MHD generator topping a steam bottoming plant is analyzed. The combined power plant involves three working fluids in three loops. The MHD loop is investigated more thoroughly since it is the least conventional of the three. Equations are developed to determine the geometric and thermodynamic variables throughout the MHD channel for inlet conditions of mass flow, temperature, pressure, and velocity. Limiting design parameters are output power, channel length, channel aspect ratio, Hall parameter, and interaction parameter. The basic closed-cycle MHD loop working fluid can consist of either argon or helium seeded with cesium. Both non-equilibrium ionization produced by the elevation of the electron temperature from joule heating of the plasma and thermal ionization are considered. Equations used to calculate the electrical conductivity and the elevation of electron temperatures are derived. These equations are coupled with the one-dimentional differential equations applicable to an MHD generator. The chief interest is in determining those MHD channel conditions which result in the most thermodynamically efficient MHD-steam plantcombination. Thus an overall heat balance forthe system is required. Equations are developed to calculate the gas properties at the various stations of the closed loop and to determine the overall efficiency of the cycle. A rather flexible computer program written in Fortran is used to solve the MHD generator equations and to make the overall heat balance. Some typical results presented demonstrate the feasibility and adaptability of the analysis for optimizing the thermal efficiency and the sensitivity of thermal efficiency to various parameters. 相似文献
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Introduction Infrared (IR) drying of paper in a pilot scale has been investigated by several researchers in the past [1–3]. Both high-intensity electric heating and medium-intensity gas heating are now being used industrially either to preheat wet paper before conventional steam drying [1] or as a moisture-profile corrector just before paper sizing press [2]. Our own investigation [3] on the use of radiant energy from a gas-fired IR radiator have revealed that the drying efficiency of IR radiation is influenced by the nature of association of water molecules with cellulose in wet paper. Depending on the total moisture content of a paper, the free and bound moisture contents of paper will vary in wet paper sheet. Our previous study [3] has also confirmed that it is possible to remove free moisture more efficiently using gas-fired IR emitter operated at 1373 K rather than as 1223 K. It is reported that besides emitter temperature, the efficiency of drying also depends on the location of the emitter. In general, the efficiency is high if the emitter is installed near the preheating zone and the efficiency changes in the following order: falling rate < constant rate < preheating. Pikulik [4] compared the efficiency of hot gas impinging drying with conventional steam drying emphasizing the paper properties. The properties of a high-intensity hot gas-dried paper has been reported to be better than those of conventionally steam dried paper. An immediate quality improvement in terms of reduced moisture steaks and superior resistance to paper embrittleness was also observed when installing a high-intensity infrared drying system [5,6]. 相似文献
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《Heat Recovery Systems and CHP》1991,11(6):517-521
Decrease of fuel supplies and cost increases make it vital for industries, especially energy intensive ones, to consider conserving available sources and convert losses into sources of energy.In this paper, a gas turbine-based cogeneration system is suggested to utilize a refinery's reformer gas in the gas turbine, and furnaces flue gases together with the engine exhaust gases in a heat recovery steam generator, HRSG. This is proposed as an alternative to the currently used system where the gas turbine and the steam generator are used separately. Operating variables comprising compressor pressure ratio and turbine inlet temperature are varied widely to evaluate performance; namely power, SFC, overall efficiency and annual fuel savings at design and off-design loading conditions using a dedicated computer program.Results show that the proposed system offers 100% higher overall efficiency and $5.25 million annual fuel saving for a 12 MWe gas turbine. 相似文献
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排气全燃型联合循环设计点性能简明估计公式 总被引:1,自引:0,他引:1
排气全燃型联合循环设计点性能简明估计公式蔡睿贤(中国科学院工程热物理研究所北京10O080)关键词:排气全燃型联合循环,热力分析主要符号表Hu燃料热值L燃料理论空气量l比功P单位能量价格R燃气轮机与蒸汽轮机的功率比α过量空气系数β摩尔燃料系数△增量η... 相似文献
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本文对比了再压缩超临界CO2 (S-CO2)循环、蒸汽朗肯循环、He布雷顿循环分别应用于铅基堆的最优热学性能,明确了S-CO2循环与铅基堆结合较传统循环的热力学优势。为进一步提高再压缩S-CO2循环的效率,以跨临界CO2 (T-CO2)循环为底循环构建了再压缩S-CO2/T-CO2复合循环,探讨了不同顶循环透平入口温度、压力和压缩机入口温度条件下系统性能的变化规律,对比了S-CO2/T-CO2复合循环和S-CO2循环的热学性能。结果表明:铅基堆再压缩S-CO2循环发电系统较传统循环形式具有更高的热效率;构建的S-CO2/T-CO2复合循环能够有效提高S-CO2循环的效率,在所研究参数范围内,S-CO2/T-CO2复合循环的热效率和效率比S-CO2循环分别最大可提高约4.8%和8.3%;再压缩S-CO2循环和S-CO2/T-CO2复合循环热学性能随顶循环关键参数变化规律具有一致性。 相似文献
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A new approach has been developed to solve the optimization problems of continuous parameters of thermal power plants. It is based on such organization of optimization, in which the solution of the system of equations describing thermal power plant, is achieved only at the endpoint of the optimization process. By the example of optimizing the parameters of a coal power unit for ultra-supercritical steam parameters, the efficiency of the proposed approach is demonstrated and compared with the previously used one, in which the system of equations was solved at each iteration of the optimization process. 相似文献
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新型双燃料重整联合循环发电系统 总被引:2,自引:1,他引:1
本文提出了一种新型双燃料重整联合循环发电系统。该系统通过重整反应实现了煤和天然气的综合利用,煤的燃烧过程为天然气/水蒸汽重整反应提供了高温反应热,通过双燃料重整煤的部分化学能间接转化到合成气中,然后合成气进入联合循环燃烧作功。研究结果表明双燃料联合循环的供电效率为49.4%-53.2%,煤的折合供电效率为42.4%-44.6%,与IGCC(动力部分相同时为44%-46%)相比供电效率降低1-2个百分点,但是投资大约降低30%。本文的研究开拓性地为煤的清洁高效利用提供了新途径。 相似文献
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Seok-Min Yun Jung-Hyung Kim Hong-Young Chang 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1998,26(2):159-166
The external electrical characteristics of helicon wave plasmas have been studied over a wide range of magnetic fields, radio frequency (RF) power, frequencies, and Ar gas pressures. External parameters, such as antenna voltage, current, and phase shifts, and internal parameters, such as electron density, are measured. The equivalent discharge resistance, reactance, and power transfer efficiency are calculated through these measurements. The characteristics of helicon mode is compared with inductively coupled plasma (ICP) and low mode. The power efficiency of the helicon mode is better than that of other modes. Consequently, electron density of helicon mode is much higher than that of other modes. This means the existence of a mechanism where electrons are very efficiently accelerated by the electric field of the antenna in the helicon mode. The power efficiency of helicon mode is higher at lower RF frequency and at optimum gas pressure than that of other modes 相似文献
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《Heat Recovery Systems and CHP》1988,8(3):265-270
The first part of this paper presents a waste heat recovery scheme for the Dura (Baghdad, Iraq) oil refinery energy plant. Both the wasted heat of the process return condensate and the flue gases are utilized for low temperature feedwater and fuel heating. The steam saved, both from the main steam line and turbine extraction system, was found to increase the steam and plant overall efficiency by 18%.An alternative cogeneration energy plant is presented in the second part of this study. The proposed plant utilizes the gas turbine exhaust, in conjunction with a heat recovery boiler, to produce the process steam requirement. With this alternative plant, the overall efficiency increases by 31.6%, while the steam efficiency increases by 19%. The outstanding features and advantages of the proposed plants are highlighted. 相似文献