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本文利用Yong分析方法建立了以易测参数表示的、可实现在线的发电厂管道各项Yong损失的计算式。详细分析了影响管道损失的各种因素,指出能分析和Yong分析的区别,并结合300MW机组的实际热力系统给出了计算实例,计算实例表明,再热蒸汽管道Yong损失最大,这与能分析的结论是不同的。 相似文献
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依据热力学基本定律 ,本文从火用平衡的角度分析了常压锅炉的能量转换利用过程 ,并通过实例计算 ,分析比较了热平衡和火用平衡的各项火用损失。同时指出了常压锅炉节能的主要方向 (减少锅炉内部损失 )和措施。 相似文献
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通过分析大型CFB锅炉(火用)效率的计算方法,建立了CFB锅炉炯损失的数学模型,对我国引进型300 MW CFB锅炉的(火用)损失和炯效率进行了计算,并与热量法的计算结果进行了比较.结果表明:(火用)方法比热量法更能全面地反映电站锅炉的各种损失以及产生的部位;锅炉(火用)效率远低于热效率的原因在于锅炉不仅存在外部损失,还存在大量的不可逆内部损失;锅炉主要外部损失仍为排烟热损失和机械不完全燃烧(火用)损失;从降低炉内平均温度与提高炉内水和蒸汽的平均温度两方面采取措施,可减少传热过程中的(火用)损失,提高锅炉效率. 相似文献
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水泵吸入压力降低会引起泵的汽蚀。这就要求在改造水泵吸入管道时应必须保证吸入管道的阻力损失不能大于原来的阻力损失。从实例出发,分析得出管道阻力的估算方法,提出了管道阻力计算时存在的、不可忽略的“瓶颈”问题。 相似文献
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In the present work, exergy analysis of a coal‐based thermal power plant is done using the design data from a 210 MW thermal power plant under operation in India. The entire plant cycle is split up into three zones for the analysis: (1) only the turbo‐generator with its inlets and outlets, (2) turbo‐generator, condenser, feed pumps and the regenerative heaters, (3) the entire cycle with boiler, turbo‐generator, condenser, feed pumps, regenerative heaters and the plant auxiliaries. It helps to find out the contributions of different parts of the plant towards exergy destruction. The exergy efficiency is calculated using the operating data from the plant at different conditions, viz. at different loads, different condenser pressures, with and without regenerative heaters and with different settings of the turbine governing. The load variation is studied with the data at 100, 75, 60 and 40% of full load. Effects of two different condenser pressures, i.e. 76 and 89 mmHg (abs.), are studied. Effect of regeneration on exergy efficiency is studied by successively removing the high pressure regenerative heaters out of operation. The turbine governing system has been kept at constant pressure and sliding pressure modes to study their effects. It is observed that the major source of irreversibility in the power cycle is the boiler, which contributes to an exergy destruction of the order of 60%. Part load operation increases the irreversibilities in the cycle and the effect is more pronounced with the reduction of the load. Increase in the condenser back pressure decreases the exergy efficiency. Successive withdrawal of the high pressure heaters show a gradual increment in the exergy efficiency for the control volume excluding the boiler, while a decrease in exergy efficiency when the whole plant including the boiler is considered. Keeping the main steam pressure before the turbine control valves in sliding mode improves the exergy efficiencies in case of part load operation. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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The objective of the study is to identify the ‘best’ possible power plant configuration based on 3‐E (namely energy, exergy, and environmental) analysis of coal‐based thermal power plants involving conventional (subcritical (SubC)) and advanced steam parameters (supercritical (SupC) and ultrasupercritical (USC)) in Indian climatic conditions using high ash (HA) coal. The analysis is made for unit configurations of three power plants, specifically, an operating SubC steam power plant, a SupC steam power plant, and the AD700 (advanced 700°C) power plant involving USC steam conditions. In particular, the effect of HA Indian coal and low ash (LA) reference coal on the performance of these power plants is studied. The environmental impact of the power plants is estimated in terms of specific emissions of CO2, SOx, NOx, and particulates. From the study, it is concluded that the maximum possible plant energy efficiency under the Indian climatic conditions using HA Indian coal is about 42.3% with USC steam conditions. The results disclose that the major energy loss is associated with the heat rejection in the cooling water, whereas the maximum exergy destruction takes place in the combustor. Further, the sliding pressure control technique of load following results in higher plant energy and exergy efficiencies compared to throttle control in part‐load operation. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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In this paper, a thermodynamic analysis of a subcritical boiler–turbine generator is performed for a 32 MW coal-fired power plant. Both energy and exergy formulations are developed for the system. A parametric study is conducted for the plant under various operating conditions, including different operating pressures, temperatures and flow rates, in order to determine the parameters that maximize plant performance. The exergy loss distribution indicates that boiler and turbine irreversibilities yield the highest exergy losses in the power plant. In addition, an environmental impact and sustainability analysis are performed and presented, with respect to exergy losses within the system. 相似文献
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火电机组的热经济性分析 总被引:6,自引:0,他引:6
为进行整个火电机组的能量系统热经济性分析及考察其组元变化的影响,提出了以热经济学和边际成本概念为基础的热经济性分析方法。对复杂能量系统主要以功能划分后形成的组元,考察其组元的输出炯流变化引起整个系统的能耗变化,可以通过边际炯成本、单位炯成本和组元产品的函数来表达,来衡量整个系统所有组元的输出炯流变化对系统外部输入燃料的影响,便于火电机组的运行经济状态动态评估。通过300MW机组主蒸汽参数变化的计算表明:参数变化时将引起系统的煤耗增加,降低了经济性,因而从本质上进行了热经济性的全面综合分析,以优化机组运行,进行性能诊断。图1表2参10 相似文献
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Energy and exergy analysis were carried out for a combined‐cycle power plant by using the data taken from its units in operation to analyse a complex energy system more thoroughly and to identify the potential for improving efficiency of the system. In this context, energy and exergy fluxes at the inlet and the exit of the devices in one of the power plant main units as well as the energy and exergy losses were determined. The results show that combustion chambers, gas turbines and heat recovery steam generators (HRSG) are the main sources of irreversibilities representing more than 85% of the overall exergy losses. Some constructive and thermal suggestions for these devices have been made to improve the efficiency of the system. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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In this study, a modified exergoeconomic model is proposed for geothermal power plants using exergy and cost accounting analyses, and a case study is in this regard presented for the Tuzla geothermal power plant system (Tuzla GPPS) in Turkey to illustrate an application of the currently modified exergoeconomic model. Tuzla GPPS has a total installed capacity of 7.5 MW and was recently put into operation. Electricity is generated using a binary cycle. In the analysis, the actual system data are used to assess the power plant system performance through both energy and exergy efficiencies, exergy losses and loss cost rates. Exergy efficiency values vary between 35% and 49% with an average exergy efficiency of 45.2%. The relations between the capital costs and the exergetic loss/destruction for the system components are studied. Six new exergetic cost parameters, e.g., the component annualized cost rate, exergy balance cost, overall unavoidable system exergy destruction/loss cost rate, overall unavoidable system exergy destruction/loss cost rate, overall unavoidable system exergy production cost rate and the overall unavoidable system exergy production cost rate are studied to provide a more comprehensive evaluation of the system. 相似文献
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Performance and parametric investigation of a binary geothermal power plant by exergy 总被引:1,自引:0,他引:1
Exergy analysis of a binary geothermal power plant is performed using actual plant data to assess the plant performance and pinpoint sites of primary exergy destruction. Exergy destruction throughout the plant is quantified and illustrated using an exergy diagram, and compared to the energy diagram. The sites with greater exergy destructions include brine reinjection, heat exchanger and condenser losses. Exergetic efficiencies of major plant components are determined in an attempt to assess their individual performances. The energy and exergy efficiencies of the plant are 4.5% and 21.7%, respectively, based on the energy and exergy of geothermal water at the heat exchanger inlet. The energy and exergy efficiencies are 10.2% and 33.5%, respectively, based on the heat input and exergy input to the binary Rankine cycle. The effects of turbine inlet pressure and temperature and the condenser pressure on the exergy and energy efficiencies, the net power output and the brine reinjection temperature are investigated and the trends are explained. 相似文献
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基于过程系统工程的建模和仿真原则,针对某电厂300MW燃煤机组开发了一套稳态热力学仿真系统,并详细阐述了模型建立的基本思路和方法,通过改变输入参数、负荷和环境条件,仿真电厂在不同工况下的运行特性.结果表明:系统仿真所获得的结果与实际电厂的性能测试数据相比误差不超过2%;通过仿真可获得主要物流、能流的热力学参数(包括质量流量、温度、压力、比焓、比熵等)和主要设备的运行参数(包括汽轮机和泵的等熵效率、加热器端差、热传导系数等),为燃煤电厂的实际运行优化、炯分析、热经济学分析等提供基础数据. 相似文献
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根据分析理论,把锅炉、汽轮机及发电厂热力系统作为一个整体,通过对发电厂各环节进行分析找到具体损失环节并对具体位置提出改造方案,是发电厂改造的一种新方法。以某超超临界机组为例,运用分析理论找到损失环节,找到二次风温及给水温度对锅炉系统及电厂热力系统影响的关系,通过增加一级高压加热器提高给水温度,同时在保证锅炉排烟温度不变的前提下适当地提高二次风温,分析在给水温度及二次风温的双重作用下,锅炉乃至整个机组性能的变化。结果表明,当给水温度由299.5℃升高至322℃时,二次风温由327.8℃升高至360℃,锅炉系统传热损失由3 443 kJ/kg降低至3 254 kJ/kg,燃烧环节损失由6 204 kJ/kg降低至6 158 kJ/kg,锅炉效率由54.15%升高至54.45%,机组目的效率由42%升高至46.7%。 相似文献