燃气–蒸汽联合循环余热锅炉滑压运行

Sliding Pressure Operation of Gas-steam Combined Cycle Heat Recovery Boiler

联合循环机组在运行过程中会偏离设计条件,如燃气轮机排气温度升高、燃气轮机排气流量变化等,但汽轮机依旧按原既定的滑压曲线方式运行,实际运行时偏离最佳的参数匹配。对此,采用MATLAB建立余热锅炉–汽轮机的仿真计算模型,优化得到余热锅炉–汽轮机的滑压参数,比较燃气轮机不同排气条件下余热锅炉最佳滑压曲线的变化情况。结果表明:当燃气轮机效率下降,机组按控制燃气轮机排气温度方式运行时,余热锅炉最佳滑压曲线上移;同时,燃气轮机效率下降导致排气流量上升,使得汽轮机出力升高,在一定程度上减小了燃气轮机效率下降对联合循环机组出力下降的影响。

During its operation process, the combined cycle unit will deviate from designed conditions, such as rise of exhaust gas temperature, change of exhaust gas flow, and so on, but the steam turbine will still keep its original sliding pressure curve mode, so it will deviate from optimal parameters in actual operation. This paper uses MATLAB to establish a simulation calculation model for heat recovery boiler-steam turbine for optimizing sliding pressure parameters and compares changes of optimal sliding pressure curves under different exhaust gas conditions of the gas-steam turbine. Results indicate that when efficiency of the gas-steam turbine decreases and the unit runs with the mode of controlling exhaust gas temperature of the turbine, the optimal sliding pressure curve of the boiler will move up. Meanwhile, decline of efficiency of the turbine will cause rise of exhaust gas flow and increase of output of the turbine, which will reduce influence of efficiency decline of the turbine on decrease of output of the combined cycle unit.