燃气–蒸汽联合循环热电联产机组多种运行方式负荷特性研究

Study on Load Characteristics of Multiple Operation Modes of Gas-steam Combined Cycle Cogeneration Unit

以9FB型联合循环机组为案例,进行各主要部件数学建模,获得联合循环机组整体计算模型。针对抽凝、背压供热模式及一拖一、二拖一驱动方式,进行变工况热力性能分析,得到联合循环供热机组多种运行方式电、热负荷特性;优化机组不同供热期运行方式,获得电负荷可调节范围,并深入研究机组参与调峰的热经济性。研究表明:供热初末期热负荷较低时,机组宜通过一拖一背压模式与二拖一抽凝模式配合运行,调峰容量比为52.6%~53.4%;供热负荷较大时宜采用二拖一背压模式与二拖一抽凝模式配合,调峰容量比为44.5%~55.4%;严寒期为保障供热需求,调峰容量比降至27.4%~33.5%。优化后整个供热季联合循环供热机组灵活性显著提高,可为可再生能源电提供11.76亿kW·h上网空间。

Taking 9 FB combined cycle unit as a case study,the mathematical model of main components was established and the overall calculation model of the combined cycle unit was obtained.Aiming at the heating mode of adjustable extraction or back pressure and the driving mode of two-on-one or one-on-one,the unit thermodynamic performance is analyzed to obtain the power and heat load characteristics under variable operating conditions.The unit operation mode was optimized to obtain the adjustable range of electric load in different heating periods and the thermal economy in peaking operation was studied.The results indicate that when heat load is low at the beginning or end of heating period,the unit had better be in coordination of two-on-one adjustable extraction mode and one-on-one back pressure mode,and the peaking capacity ratio is 52.6%~53.4%.When the heating load gets higher,the unit had better be in coordination of two-on-one adjust extraction mode and two-on-one back pressure mode,the peaking capacity ratio is 44.5%~55.4%at cold period,and 27.4%~33.5%at the coldest period in order to ensure the demand of heating.After optimization,the flexibility of combined cycle heating unit in the whole heating season is significantly improved,which could provide 1.176 billion kW·h for renewable energy.