超临界对冲燃烧锅炉水冷壁向火侧起皮成因分析

Cause Analysis on Water-wall Fireside Oxidation in a Supercritical Opposed Firing Boiler

针对某电厂超临界对冲燃烧锅炉燃烧器区域水冷壁出现大面积氧化皮的现象,结合冷态空气动力场试验以及对氧化皮的宏观检查和取样样品的成分分析,通过数值模拟对炉内流动、燃烧和传热传质等进行了研究.结果表明:燃烧器区域水冷壁向火侧过热氧化是水冷壁氧化皮产生的主要原因;采取燃烧调整、减小靠近两侧墙燃烧器的出力、喷涂防腐涂层和定期检查并更换水冷壁管等措施后,水冷壁氧化起皮现象得到了明显抑制.

In view of the large oxidation area occurring in water wall around burners of a supercritical opposed firing boiler,the in-furnace flow,combustion and heat/mass transfer were numerically simulated based on cold aerodynamic field test,as well as macroscopic examination and composition analysis of the scale samples.Results show that the formation of oxide scales is caused by overheating over the fireside water wall adjacent to burners.The oxidation phenomenon is finally inhibited after taking following measures,such as adjusting the in-furnace combustion,reducing the output of burners near two side walls,painting anti-corrosion layer,performing regular inspection and replacing relevant tubes,etc.