燃煤锅炉高温硫腐蚀浅析

The Analysis on High Temperature Corrosion of Coal Fired Boiler

本文阐述了高温硫腐蚀的形成过程、影响因素、高温腐蚀防治方法和高温腐蚀数值模拟等方面。得出:(1)高温硫腐蚀的发生过程极为复杂,其根本原因在于水冷壁附近存在还原性物质(CO、H、OH)导致的煤中硫物种向H2S和气态单质S等腐蚀性物质的转化。腐蚀性物质不仅破坏金属管壁表面的氧化膜,同时还与内部金属反应,产生恶性循环;(2)贴壁风法是现阶段主流的高温腐蚀防治方法,其在预防近壁处H2S等腐蚀性物质的生成起到了关键作用,但在影响锅炉燃烧效率、运行成本过高等方面还有待进一步提高;(3)数值模拟研究中的总包反应机理和详细反应机理各有优劣,两者结合是现在高温硫腐蚀数值模拟的主流方法,能够很好预测炉内高温腐蚀,在结果精确度上还存在较大误差。

In this paper,the formation process,influencing factors,prevention methods and numerical simulation of high-temperature sulfur corrosion are described.It is concluded that:(1)The occurrence process of high-temperature sulfur corrosion is extremely complex,and the basic reason is that there are reducing substances(CO,H,OH)near the water wall,which lead to the transformation of sulfur species in coal to corrosive substances such as H2S and gaseous elemental S.Corrosive substances not only destroy the oxide film on the surface of the metal pipe wall,but also react with the internal metal,resulting in a vicious cycle;(2)Wall attached air method is the mainstream high-temperature corrosion prevention method at the present stage,which plays a key role in preventing the formation of corrosive substances such as H2S near the wall,but it still needs to be further improved in terms of affecting boiler combustion efficiency and operating costs;(3)The total package reaction mechanism and the detailed reaction mechanism in the numerical simulation research have their own advantages and disadvantages.The combination of the two is the mainstream method for the numerical simulation of high-temperature sulfur corrosion,which can well predict the high-temperature corrosion in the furnace,and there is still a large error in the accuracy of the results.