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直接空冷凝汽器理论最佳背压的研究 总被引:5,自引:0,他引:5
为了更好地提高直接空冷机组系统运行的经济性,本文以直接空冷系统为研究对象,以空冷系统的热力模型为基础,综合考虑汽轮机功率与空冷风机耗功率,从理论上探索研究运行工况下的最佳背压以及有关主要因素对最佳背压影响的基本规律,从而为直接空冷机组的冷端优化和经济运行提供指导. 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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《Heat Recovery Systems and CHP》1995,15(1):41-50
The performance of gas turbines, operated either as a simple cycle or a combined cycle, is critically constrained by the prevailing ambient temperature, particularly in arid and tropical climates. This paper investigates the option of cooling the intake air to the compressor of the gas-turbine system using an absorption chiller in order to increase the gas turbine capacity. High-temperature waste heat from the exhaust gas may be utilized to produce steam in a recovery boiler. Part of the steam produced could then be used to drive a lithium-bromide double-effect absorption chiller which in turn could cool the incoming air. An analysis carried out by taking the weather data of Bangkok (Thailand) indicates that reducing the temperature from ambient condition to 15°C could help to increase the instantaneous power output between 8 and 13%. As an outcome, as much as 11% additional electricity could be generated from the same gas turbine power plant.A simple economic assessment indicates that the proposed scheme will require a minimal investment as compared to the commissioning cost of a new gas turbine unit to meet the corresponding capacity increment. The latter will need nearly four times higher initial cost than the amount estimated for the proposed scheme. Thus, implementation of such a system would significantly abate the negative impact of the ambient temperature, while providing an economically and environmentally attractive option for energy producers in most developing nations of the world which are located in arid and tropical zones. 相似文献
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汽轮机湿蒸汽级中凝结流动的三维数值分析 总被引:1,自引:0,他引:1
对一台凝汽式汽轮机低压末三级中的湿蒸汽自发凝结流动进行了三维数值分析,并与忽略自发凝结影响的流动计算结果进行了比较。结果表明,自发凝结流动中,湿蒸汽级组内焓降在各级之间的分配、各级反动度、级的工作压力范围、叶栅出口气流角和出口气流速度发生明显变化。各湿蒸汽级处于“变工况”运行状态,部分湿蒸汽级内流动状况显著变差,并导致叶片强度与振动方面安全性降低。除非平衡凝结损失外,凝结导致湿蒸汽透平级“变工况”运行是湿蒸汽级效率降低的重要原因。 相似文献
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《Heat Recovery Systems and CHP》1990,10(1):37-48
Cogeneration systems often provide a very effective means of integrating power generation with the provision of thermal energy to an industrial process. Various types of power generating machines can be used, but combined cycle cogeneration systems can offer significant advantages over other technologies in many medium and large scale applications. The systems that are used consist of fired prime movers (usually gas turbines), discharging their exhaust heat into heat recovery steam generators. The steam raised in this way is passed through back-pressure steam turbines to extract additional power before finally delivering its residual heat content to process heating duties.This paper presents an overview of the economic trade-offs in the design of single cycle and combined cycle systems. Generalizations are derived from this investigation, leading to the identification of three distinct classes of problem for which different types of cogeneration systems (combined cycle or single cycle) are appropriate. Case study results are presented to illustrate the principles employed. 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》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》1995,15(4):357-368
In combined power-desalting (plants, high available steam (at high pressure temperature) is expanded first in a steam turbine (and thus produces work) before its extraction (from the turbine) as a heat source to the desalters. The amount of energy consumption charged to the predominantly used multi-stage flash (MSF) desalter in this combined heat and power plant is a question of great concern in the Gulf area. The following are among the methods used to answer this questions (i) the available energy of the heat supplied to the desalter; (ii) work loss from the lower pressure stages of the steam turbine due to steam extracted to the desalter; (iii) energy charged if a separate boiler was used to supply the desalter with its required heat; and (iv) the excess energy supplied to the combined power desalting plant as compared to a single purpose power plant producing the same power output. There would be a different rating method of the power producing process associated with any of the above mentioned charging methods. In this paper, the MSF desalting method and its power consumption are outlined, together with the rating method of the power-desalting plants and the energy charged to the desalter methods. These rating methods are applied to real cases of dual purpose plants working in Kuwait. 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
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Z.L. Lu D.C. Li Z.Q. Tong Q.P. Lu M.M. Traore A.F. Zhang B.H. Lu 《Optics and Lasers in Engineering》2011,49(9-10):1101-1110
In order to achieve high precision and unidirectional solidification microstructure of steam turbine blade fabricated by direct laser forming (DLF), this study is focused on the influence of the laser scanning speed, specific energy and powder feeding rate on the forming characteristics of single cladding pass, which is elementary units in DLF, and a new method of columnar crystal preparation is investigated. Results show that both the metal powder stream and the laser specific energy are the most important factors, that control the high temperature behavior of molten pool so as to determine the micro-morphology of laser scanning track. Based on the optimum processing conditions, high definition steam turbine blade of 316L is fabricated (surface roughness Ra of 10.08 to 26.51 μm or so). The microstructure is of fish scale type by natural cooling after DLF, but it is first found that columnar crystals can be formed on the non-columnar crystal substrate of 316L by intermittent cooling with liquid argon. Therefore, the above investigations will benefit the rapid development of steam turbine blade. 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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本文基于Aspen plus软件对燃用低热值煤气的燃气蒸汽联合循环系统进行了模拟仿真。在该仿真平台上对系统设计工况进行了计算验证。在设计工况下,燃气透平进口温度为1000~1050℃,模拟计算结果为1016.2℃。燃气透平出口温度设计参数为517.2℃,模拟结果为519.2℃。结果表明仿真模型能够准确模拟系统稳态情况的各种工况。本文还运用矩阵模式热经济学的方法对系统设计工况下的(?)流成本进行了计算分析,对系统进行了技术经济评价。燃气轮机和蒸汽轮机电能耗费的能量成本分别为22.2,24.06和16.64$·GJ-1。 相似文献
15.
L. Schnatbaum 《The European physical journal. Special topics》2009,176(1):127-140
The solar thermal power plant technology, the opportunities it presents and the developments in the market are outlined. The
focus is on the technology of parabolic trough power plants, a proven technology for solar power generation on a large scale.
In a parabolic trough power plant, trough-shaped mirrors concentrate the solar irradiation onto a pipe in the focal line of
the collector. The thermal energy thus generated is used for electricity generation in a steam turbine. Parabolic trough plants
can be combined with thermal storage and fossil or biomass fired heat exchangers to generate electricity even when the sun
is not shining. Solar Millennium AG in Erlangen has developed the first power plant of this kind in Europe. After two years
of construction the plant started operation in Southern Spain in 2008. This one and its sister projects are important steps
leading the way for the whole market. The paper also covers the technological challenges, the key components used and the
research and development activities concerning this technology. Solar thermal power plants are ideal for covering peak and
medium loads in power grids. In hybrid operation they can also cover baseload. The Solar Chimney power plant, another striking
technology for the conversion of solar into electric energy, is described briefly. The paper concludes with a look at the
future – the import of solar energy from the deserts of North Africa to central Europe. 相似文献
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《Heat Recovery Systems and CHP》1990,10(2):151-159
In Sweden, Combined generation of Heat and Power (CHP) is in common practice. Different fuels are burnt in a boiler and the steam is used for generating electricity. The heat that has to be transferred from the condenser in the plant is used in the district heating grid. This grid is thus used as a cooling facility necessary for electricity production. However, energy conservation the Swedish building stock is also encouraged, and if this is utilized in district heated buildings it results in fewer possibilities for electricity production. This might be a major drawback when nuclear power is abolished, as is the result from a consensus some years ago. This paper deals with the question of whether it is better to conserve both heat and electricity, to save only one of the energy forms or if it is cheaper to produce more energy, instead of saving. A case study is presented dealing with Malmö, in the South of Sweden, and it is shown that energy conservation in district heated buildings cannot yield profitability: neither can conservation in the electricity grid, even if it gets closer to profitable savings. It is assumed that the total cost of heating, insulation and electricity is paid by the society and the minimum point for this cost will characterize the best solution. 相似文献
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《Heat Recovery Systems and CHP》1988,8(2):149-156
This study presents a novel power generating cycle suitable for solar energy applications. A modified version of the conventional LiBr-H2O absorption refrigerating machine is used for the proposed cycle. The condenser, expansion valve and evaporator are replaced by a superheater and a steam turbine, while a flashing tank replaces the generator. The cycle is powered by medium concentrators with a solar collecting temperature of 165°C. Steam generated in the flashing tank (100 kPa) is superheated (using fuel) to 600°C before it expands in the turbine down to 1.25 kPa. This is maintained by the equilibrium conditions in a water cooled absorber, LiBr-H2O solution is directly circulated in the solar collectors and the non-solar energy input to the system is 23% of its total requirements.Results showed that using a 710 ton refrigeration absorption machine, the SFAPC would generate 960 kW shaft power at a system thermal efficiency of 25% which is 44% higher than the available systems. Moreover, when the SFAPC is combined with a vapour compression refrigerator, an overall COP of 1.4 is obtained. This is 72% higher than that of the absorption machine alone at the expense of 23% non-solar energy supply. 相似文献