关于环已酮废液焚烧余热锅炉卫燃带腐蚀脱落的理论分析与对策

Theoretical Analysis and Countermeasures on Refractory Belt Corrosion and Fall off in Cyclohexanone Wastewater Incineration Waste Heat Boilers

环已酮废液焚烧烟气中大量的熔融碳酸钠,对余热锅炉中的卫燃带的腐蚀是不可避免的。因为设计和施工的质量问题,或因为不恰当的超温运行,所以卫燃带的使用寿命长的只有2年左右,短的一年不到甚至2个月左右。烟气中的热量传给工质水的路径,依次是熔融盐层、固体盐层、卫燃带耐火层、膜式水冷壁管金属厚度层。本文应用传热学基础理论和有关热力计算的标准方法,从已知的膜式水冷壁管内的工质温度开始,按热量传导的相反方向,分析并计算出熔融盐层的烟气侧的温度,即炉膛内向火的壁面温度,借此求解炉膛运行的平均烟气温度。因为固体盐的腐蚀性比熔融盐的低一个数量级,所以控制炉膛运行的平均烟气温度、卫燃带设计的综合导热系数和应有的耐火性和耐磨性,使卫燃带表面刚好能形成固体盐层,如此就能使卫燃带的使用寿命达到最佳的水平。

Lots of molten sodium carbonate is contained in cyclohexanone wastewater incinerations flue gas, which could etch waste heat boiler ignition belt inevitably. Because of the quality problems of design and construction, or the inappropriate operation over temperature, the service life of refractory belt is about two years, as the shortest is less than two months. The path flue gas heat transferring to working medium water is by molten salt layer, solid salt layer, refractory layer refractory belt, membrane water wall tubes of metal layer thickness. Using the basic theory of heat transfer and thermal calculation standard method, beginning from the known temperature of the working fluid in the membrane wall tube, along opposite direction of heat conduction, this paper analyzes and calculates the temperature of flue gas side of the molten salt layer, that is the wall temperature facing furnace heating surface, thereby the average furnace flue gas temperature in operation is solved. Because the corrosivity of solid salt is much more lower than molten salt, it would be nessary to control the average gas temperature in furnace operation, the design thermal conductivity in refractory belt integrated, proper fire resistance and abrasion resistance, to formulate refractory belt solid salt layer on the surface, and keep life cycle refractory belt in the optimum level.