水冷壁大面积腐蚀原因分析

Cause Analysis of Large Area Corrosion of the Water Wall

某燃煤电厂炉膛水冷壁管外壁产生大面积腐蚀减薄,为分析其产生原因,在进行现场调查后,取样进行宏观形貌检查、化学成分分析、金相检验、常温力学性能试验和能谱分析。分析表明,锅炉在未经任何计算和改造的情况下改烧有烟煤,使得炉膛的运行工况发生改变,从而加速了某些特殊区域的高温硫腐蚀,最终在易腐蚀的焊缝及附近部位发生严重腐蚀减薄。结合分析结果和电厂实际情况,提出了相应的改进措施。

The outer wall of water-cooled tube in furnace of a coal-fired power plant was corroded and thinned.In order to analyze the cause,macroscopic morphology,chemical composition analysis,metallographic examination,normal temperature mechanical property test and energy spectrum analysis were conducted after field investigation.The analysis shows that the plant boiler changed to burning bituminous coal without any calculation and modification,which changed the operation condition of the hearth,causing the high-temperature sulphidation in some special areas accelerated.Serious corrosion and thinning at the vulnerable weld and its adjacent parts can be growing in a short time.Based on the analysis results and the actual situation of the power plant,the corresponding improvement measures are proposed.