超(超)临界汽轮机组滑压运行优化试验

Optimization test of sliding pressure operation on large supercritical steam turbine

主蒸汽压力、汽轮机高压缸效率、给水泵汽轮机(小机)进汽流量及给水泵焓升是机组滑压运行时影响汽轮机热耗率的4个主要因素。以超超临界1 000MW机组和超临界600MW机组为例对其进行计算分析,指出汽轮机高压缸效率随主蒸汽压力的变化特性是影响主蒸汽最佳滑压点的根本原因,并进行了不同汽轮机配汽方式的滑压运行优化试验验证。结果表明,节流配汽汽轮机在调节阀全开处出现最佳主蒸汽压力点;喷嘴配汽汽轮机高压缸效率与主蒸汽压力呈非线性关系,因此在汽轮机高压缸效率变化拐点处将出现最佳主蒸汽压力点;获得初步试验结果后,应在各主要机组负荷下进行负荷变动试验,确定最终的运行定滑压曲线。

Four major factors that affect the turbine heat rate during the unit sliding pressure operation were presented,like the main steam pressure,high pressure cylinder efficiency,inlet steam flow of the feedwater pump steam turbine,and enthalpy rise of the feedwater pump.An ultra supercritical 1 000MW unit and a supercritical 600MW unit were taking as the example to conduct the calculation.The variation of the high cylinder efficiency against the main steam pressure was considered as the basic reason that affects the optimal sliding pressure point of the main steam. Moreover,the sliding pressure operation optimization test was carried out under different steam distribution modes.The results show that,the optimal main steam pressure point of the throttlegoverned steam turbine appeared when the steam turbine regulating valve was fully open.The high pressure cylinder efficiency of the nozzle-governed steam turbine showed a nonlinear relationship with the main steam pressure,so the optimal main steam pressure point of this turbine appeared at the flex point of the high pressure cylinder efficiency.After the preliminary experimental results were obtained,the load variation test should be performed to find the final operation fix-sliding pressure curve.