电站锅炉水冷壁腐蚀原因分析

Analysis of Corrosion Causes of Water Wall of Utility Boiler

某电厂在检修中发现,4#锅炉燃烧器高负荷区域(距A层喷燃器0.5 m高度左墙、后墙)水冷壁管存在高温腐蚀现象。锅炉为上海锅炉有限公司设计、制造的具有亚临界、控制循环、一次中间再热、单炉膛、平衡通风、固态排渣、控制循环汽包、可实现燃烧器摆动调温四角切圆燃烧、全钢悬吊结构、半紧封闭布置特性的Ⅱ型燃煤汽包锅炉。该处水冷壁管为内螺纹钢管,设计规格Φ51 mm×6.5 mm,材质为SA-210A1。文章采用宏观检测、微观分析、化学成分分析、力学性能试验以及金相检验等方法,对此次水冷壁腐蚀原因进行试验分析。

During the maintenance of a power plant,it was found that the water-cooled wall tubes in the high load area(left wall and back wall 0.5 m high from the A layer burner)of boiler 4#had high temperature corrosion.The boiler is designed and manufactured by Shanghai Boiler Co.,Ltd.,which is sub critical,controlled circulation,one intermediate reheat,single furnace,balanced ventilation,solid slag removal,controlled circulation drum,can realize burner swing temperature regulation,tangential firing at four corners,all steel suspension structure,and semi tight closed layoutⅡType B coal-fired drum boiler,where the water wall pipe is internally threaded steel pipe,with design specification ofΦ51 mm×6.5 mm,SA-210A1.The reasons for the corrosion of this water wall were tested and analyzed by means of macroscopic inspection,microscopic analysis,chemical composition analysis,mechanical property test,metallographic examination,etc.