300MW汽轮机中压缸抽汽口上下缸金属壁温差大原因分析及处理

Large Metal Temperature Difference Between Upper and Lower Cylinders Extraction Points Analysis of 300 MW IP Cylinder and Its Treatment

通过对某电厂2号汽轮机中压缸抽汽口上下缸金属壁温差增大的原因进行排查与分析,排除了热工仪表不准、中压汽缸下缸积水、汽缸保温不良等因素,确定引起中压缸抽汽口上下缸金属壁温差大的原因为中压缸导汽管进汽插管密封环泄漏。在不揭缸的情况下,经过多种方案比较,最终采用增加再热冷段至中压缸混温汽源的方式,将中压缸抽汽口上下缸金属壁温差控制在合理范围内,不仅达到了设计要求,而且保证了机组的安全稳定运行。

Cause analysis of large extraction point metal temperature difference between upper and lower cylinders of 300 MW IP cylinder of unit 2 showed that the leakage of admission pipe packing washer of IP cylinder steam conduit caused the large temperature difference.What＇s more,the facts of incorrect thermodynamic instrument,seeper of the lower cylinder,and cylinder lagging leading to the large temperature difference were excluded.In the case of no scale deposit removing,by comparing different projects,the project of increasing mix temperature steam source to the pipes from reheat cool section to the IP cylinder was conducted to solve the problem,by which not only the temperature difference could be controled to the normal level,but also ensured the safe and stable operation of the unit.