660 MW超超临界机组高负荷主蒸汽温度偏低原因分析

对某电厂HG2035/26.15-YM3型超超临界参数直流锅炉主蒸汽温度偏低进行了分析,找出了该厂加负荷过程主蒸汽温度低的原因.由于加负荷过程中给水泵汽轮机再循环门存在较大内漏,使给水流量达不到设计值,导致INFIT协调系统水煤质量比失调,过热度大幅波动,最终导致主蒸汽温度偏低.根据现场具体运行情况,分别制定了调整给水泵汽轮机再循环门行程、高负荷控制负荷增加速度、根据给水泵汽轮机转速调整好过热度等三项改进措施.通过运行人员认真监视和调整,未再出现主蒸汽温度偏低的现象,保证了机组的安全稳定运行.研究为同类机组提供了参考.

Causes Analysis of Low Steam Temperature for 660 MW Ultra-supercritical Unit with High Load

The causes of low steam temperature for HG2035/26.15-YM3 type ultra-supercritical once-through boiler in a power plant were analyzed.The reasons of low steam temperature in the adding load course were found out.In this course,there existed large internal leakage in the recirculation valve of feed water pump.The designed value of the water flow could not be reached.The ratio of coal to water controlled by INFIT was imbalanced.The degree of superheat fluctuated wildly.The main steam temperature was low at the end.According to the run on site,the improvements were made including stroke adjustment of feed water pump recirculation valve,rate of load increasing under high load condition,and degree of superheat adjustment according to the rotate speed of feed water pump.According to these improvements,low steam temperature didn''t occur again,which could make the unit run steadily and safely.The research could provide references for the same kind of unit.