燃气轮机排气温度对联合循环热经济性的影响

Influence of Exhaust Gas Temperature on Thermal Economy of Gas-Steam Combined Cycle Units

针对燃气轮机排气温度对整体机组变工况运行的重要性,以某三压再热余热锅炉型燃气-蒸汽联合循环机组为研究对象,将余热锅炉侧换热器分为单相换热器和蒸发换热器两类,并采用"效能-单元数"法编写换热模块,分析了燃气轮机排气温度对蒸汽系统热力参数的影响,结合"热经济分析"法探讨燃气轮机、余热锅炉及汽轮机效率的变化,进而得出机组效率和标准煤耗量随燃气轮机排气温度的变化.结果表明:模型在燃气轮机排气温度小扰动工况下有效可行,对进一步分析燃气扰动工况和机组优化运行有一定的实际参考价值.

Exhaust temperature of gas turbine is very important to operation of a power unit under variable working conditions.Taking a gas-steam combined cycle unit of the triple pressure reheat heat recovery steam generator（HRSG） as an object of study,heat exchangers at HRSG side were divided into single-phase and evaporation heat transfer two types,for which heat exchange modules were written in ε-NTU way,so as to analyze the influence of exhaust gas temperature on thermal parameters of the steam system,study the variation law of gas turbine,HRSG and steam turbine efficiency based on thermal economy analysis and subsequently obtain the relationship of unit efficiency and standard coal consumption varying with exhaust gas temperature.Results show that the proposed model is effective and feasible under light disturbance conditions of exhaust gas temperatures.This may serve as a reference for future studies of gas disturbance condition and unit operation optimization.