600MW亚临界汽轮机高压加热器疏水运行故障分析与对策

Drain Failure Analysis and Countermeasures of High Pressure Heater in 600 MW Subcritical Steam Turbine

针对600 MW亚临界汽轮机配套JG-1970-3型高压加热器正常疏水水位波动、管道晃动、端差大等故障现象进行探究,分析出JG-1970-3型高压加热器疏水冷却段包壳漏泄,壳侧蒸汽从泄漏处窜入包壳内疏水,导致高加换热效果减弱,造成高加端差大;形成汽液两相流,引起管道晃动、壳侧水位波动大。通过割管、内窥镜检查进一步确认了疏水包壳漏泄。采取割开高加疏水包壳上部壳体、疏水出口四周壳体,对检查出的疏水包壳开裂焊缝、冲刷孔洞予以补焊、加固,消除了高加疏水包壳漏泄引起的水位波动、管道晃动、端差大等缺陷,确保了高加疏水稳定运行。

This paper investigates the fault phenomenon of normal drain water level fluctuation,pipeline sloshing and large difference of JG-1970-3 HP heater in 600 MW subcritical steam turbine,and analyzes the leakage of JG-1970-3 HP heater drain cooling section.The shell side steam breaks into the drain of the shell from the leak,which weakens the heat transfer effect of the HP heater and causes a large terminal temperature difference of HP heater;a vapor-liquid two-phase flow is formed,which causes the pipe sloshing and the large shell side water level fluctuation.The leakage of the drain shell is further confirmed by tube cutting and endoscopy.The upper casing of the HP heater drain shell and the surrounding casing of the drain outlet are cut open,and the cracked welds and the flushing holes of the checked drain shell are repaired and reinforced.Therefore,defects such as water level fluctuations,pipe sloshing,and large terminal temperature differences caused by leakage of the HP heater drain shell are eliminated.The stable operation of the HP heater drain is ensured.