燃用高硫煤锅炉受热面硫腐蚀分析与防治

Analysis and Prevention of High Sulfur Coal Corrosion on Boiler Heating Surface

燃用高硫煤会引发水冷壁高温硫腐蚀减薄、横向开裂及尾部烟道的低温露点腐蚀。对三类腐蚀失效样品进行宏观检查、金相分析、扫描电子显微镜观察及能谱分析,结合现场工况,分析腐蚀机理与原因,得出燃煤全硫量及现场吹灰器布置对高温硫腐蚀具有重要促进作用的结论。基于该结论,建议电厂在检修期间加强对吹灰器附近管道壁厚进行检查,该建议已帮助多个机组顺利排除安全隐患。

High-sulfur coal burning will mainly cause high-temperature sulfur corrosion thinning of the water wall,transverse cracking of the water wall,and low-temperature dew point corrosion of the rear pass.In this paper,three types of corrosion failure samples were examined by macroscopic inspection,metallograph analysis,SEM and EDS energy spectrum analysis.Combined with on-site working conditions,the corrosion mechanism is analyzed.It was concluded that the total sulfur content of coal burning and the sootblower arrangement had an important role in promoting high-temperature sulfur corrosion.Based on this conclusion,it is suggested that the power plant should strengthen the inspection of the wall thickness of the pipes near the sootblower during the overhaul,which has helped many units to eliminate potential safety hazards.