电站锅炉水冷壁高温腐蚀现象研究

Research on the High-Temperature Corrosion Phenomenon of Boiler Water-Walls in Power Stations

为了研究水冷壁高温腐蚀经常发生的原因与腐蚀机理,以某电站锅炉水冷壁为研究对象,通过水冷壁的成分检测、厚度测量、力学性能试验,以及对腐蚀产物的扫描电镜分析、能谱分析、金相组织分析来研究引起水冷壁高温腐蚀的原因。研究结果表明:水冷壁的高温腐蚀产物可分为3层,每层腐蚀产物的形态与元素种类是不同的。该水冷壁高温腐蚀为硫酸盐型高温腐蚀,腐蚀的主要原因为生成的复合硫酸盐对管壁表面进行了破坏,而燃煤中的S、K、Na等物质的存在是发生高温腐蚀的内在根源。

In order to study the causes and corrosion mechanism of the frequent high-temperature corrosion of water-walls,this paper takes the boiler water-wall in a power station as the research object,and studies the causes of the high-temperature corrosion of the water-wall through the component detection,thickness measurement and mechanical property test of the water-wall and the scanning electron microscopy analysis,energy spectrum analysis and metallographic structure analysis of corrosion products.The results show that the high-temperature corrosion products of the water-wall can be divided into three layers,and that the morphology and element types of the corrosion products of each layer are different.The high-temperature corrosion of the water-wall is sulfate-typed high-temperature corrosion,the main cause for corrosion is that the generated composite sulfate destroys the surface of the pipe wall,and the existence of S,K,Na and other substances in coal is the internal root cause of high-temperature corrosion.