某600 MW亚临界机组锅炉水冷壁爆管原因分析

对某亚临界600 MW燃煤发电机组水冷壁爆管管样进行了爆口宏观检查、垢层形貌、垢量、种类成分及金相组织检验,认为爆管是由于水冷壁向火侧内表面发生了严重的酸性腐蚀和氢损伤所致。垢下酸性腐蚀导致水冷壁有效壁厚减薄以及氢损伤造成金属基体强度下降是造成水冷壁爆管的根本原因,建议对该锅炉进行化学清洗,加强日常化学监督工作,对易发生氢损伤管段开展无损检测,以避免爆管事故的再次发生。

Cause Analysis of Tube Burst of Water Wall in a 600 MW Subcritical Unit

To find out the leakage reason of water wall in a subcritical 600MW coal-fired generator group,the macroscopic examination,scale morphology,quality of scale,species composition,microstructure examination of tube samples have been carried out.It is believed that the blasting tube of water wall caused by severe acid corrosion and hydrogen damage to the inner surface of the water wall.Subsurface fouling caused by acidic corrosion of the water wall and the reduction of the strength of the metal matrix caused by hydrogen damage is the root cause of the water-wall tube explosion.It is recommended that the boiler chemical cleaning,strengthen daily chemical supervision and the non-destructive testing of the hydrogen damaged pipe section should be carried out to avoid the recurrence of explosion accidents.