锅炉水冷壁高温腐蚀原因分析及解决措施

Causes Analysis of High-temperature Corrosion of Boiler Water Walls and Solving Measures

某电厂锅炉两侧墙燃烧器区域水冷壁发生较严重的高温腐蚀。经化验分析,腐蚀产物主要成分为铁氧化物、铁硫化物,属典型的硫化物腐蚀。通过分析现场运行情况,并结合数值模拟,发现出现高温腐蚀的主要原因为:低氮燃烧方式下,主燃烧区过量空气系数较低,主燃区呈现较强的还原性气氛,在该气氛下,燃料中的硫容易与水冷壁管发生反应,使水冷壁被腐蚀。通过在侧墙增加特定的贴壁风喷口,还原性气氛可以得到有效缓解。

Severe high temperature corrosion occurred on the water-cooling walls in burner area of bilateral boiler in a power plant.The main components of corrosion products are iron oxides and iron sulfides,which is categorized under the typical sulfide corrosion.Through comprehensive analysis based on the actual operation and numerical simulation,the main cause of high temperature corrosion is due to vulcanization under strong reductive atmosphere which is created by low excess air coefficient under low-nitro-burning.Reductive atmosphere can be effectively alleviated by adding a specific wall-air nozzle to the side wall.