600MW机组锅炉过热器堵阀泄漏原因分析

Analysis on 600 MW Boiler Superheater Blind Flange Leakage

某电厂600 MW燃煤机组在小修后重新启动时,发现锅炉过热器堵阀有裂纹。通过对裂纹产生的时间、外观形貌和检测结果进行分析,认为此次堵阀泄漏主要是堵阀设计不合理、焊口质量差、焊接性能差、二次热应力大等原因造成的。后对发生泄漏的堵阀进行更换,并针对该类问题提出对其他重点部位堵阀进行检查,在机组启动时要严格控制升温、升压速率等建议。

600 MW coal-fired unit in a power plant in the small and restarted after repair, appeared that boiler superheater blocking valves had cracks. Through the cracks of the time, the appearance of morphology and test results analysis, the blocking valve leakage was mainly due to blocking valve design was unreasonable, weld quality was poor, poor welding performance, thermal stress and other causes. Then replacementthe leak plugging valve, and cheched the other key parts of the plug valve to check suggested strictly control the temperature and pressure rate and other recommendations when starting.