循环流化床锅炉水冷壁与水冷屏频繁爆管的分析及修复

Analysis and Repair of Frequent Tube Burst in Water Wall and Water Cooling Screen of Circulating Fluidized Bed Boiler

某纸业集团循环流化床锅炉水冷壁及水冷屏,在2016年11月9日至2017年1月19日之间,共发生8次(水冷屏6次,炉膛侧墙处水冷壁2次)爆管泄漏事故。停炉后检查水冷壁、水冷屏及水冷壁下联箱,均未发现结垢现象,但部分管段存在较深的内壁腐蚀凹坑(槽),且下联箱存在大量块状脱落物。经分析,造成爆管是炉膛內受热面受热不均,管段局部温差大,对应的管段内部产生汽泡而发生空泡应力腐蚀。本文针对该问题提出了切实可行的整改措施,经过近两年的连续性运行验证,均没有发生过爆管事故。

Between Nov 9,2016 and Jan 19,2017,the water-cooled wall of the circulating fluidized bed boiler in a paper group had happened 8 times explosion accidents.When the furnace was shut down,no fouling was observed in the water-cooled wall and the lower header after inspecting,but part sections of the pipe had some deep inner wall corrosion grooves,and the lower header had a large amount of abscission.The reason of the boiler bursting is that the heating surface of the furnace is unevenly heated,which lead to the pipe section partial overheating,so bubbles are generated inside the pipe section,which resulting in bursting.This paper proposes the practical rectification measures and no similar tube burst accidents have occurred after two years of continuous operation.