整体煤气化联合循环系统中燃气轮机的变工况特性

Off-design Characteristics of Gas Turbine in IGCC Systems

采用ThermoFlex软件建立了200 MW级整体煤气化联合循环(IGCC)系统模型,从系统的角度研究了200 MW级IGCC系统中燃气轮机的变工况特性.详细讨论了在3种调节方式下,燃气轮机负荷、整体空分系数(Xas)、氮气回注系数(Xgn)和大气环境条件对系统性能的影响.结果表明:随着燃气轮机负荷的降低,在压气机进口可转导叶(IGV)不调时,燃气透平初温(T3)和燃气透平排气温度(T4)均呈下降趋势;在等T3调节时,T4先升高后降低,转折点在80%负荷时;而在等T4调节时,T3先缓慢降低,而后快速降低,转折点在70%负荷时.在等T3调节时IGV可关闭的角度比等T4调节时的小.当Xas和Xgn增大时,系统发电效率降低.IGV可调的变工况性能比IGV不调时好.随着大气温度的升高,燃气轮机功率和系统功率均下降.当Xas=0.3时,燃气轮机功率和系统功率均随Xgn的增大而增加.

Off-design characteristics of gas turbine in a 200 MW integrated gasification combined cycle（IGCC） system was studied based on system model built with ThermoFlex software from the system point of view.Influence of gas turbine load,air separation unit（ASU） integrated coefficient（X_（as））,nitrogen reinjection coefficient（X_（gn）） and atmospheric conditions on the system performance was analyzed in detail under three adjusting modes.Results show that when the compressor inlet guide vane（IGV） is kept at a constant angle,both the gas turbine inlet temperature（T_3） and exhaust temperature（T_4） will drop with the reduction of gas turbine load.Under conditions that IGV is adjusted and gas turbine load reduced,if T_3 is kept constant,T_4 will first rise and then decrease,with the turning point at about 80% load;whereas if T_4 is kept constant,T_3 will first slowly and then quickly reduce,with the turning point at about 70%.Under the adjusting mode of keeping T_3 constant,the adjustable degree of IGV angle is smaller than that of keeping T_4 constant.Off-design performance of the system under IGV adjustable condition is better than IGV fixed condition.When atmospheric temperatures climb,both the gas turbine and the system power will reduce,and in the case of X_（as）=0.3,above two powers will rise with growing X_（gn）.