前后墙对冲锅炉炉内混烧下受热面结渣特性数值模拟

Numerical Simulation of Slagging Characteristics of Co-fired in Opposed Boiler Heating Surface

为探究多煤种炉内混烧对炉膛结渣特性的影响规律,实现防结渣燃烧优化,该文建立考虑飞灰颗粒运动与沉积过程的350MW前后墙对冲煤粉锅炉燃烧数理模型,实现灰颗粒在壁面沉积过程的模拟计算。结果表明:在燃用单一煤种时,炉内整体结渣情况较好;而采用炉内混烧时,不同的混烧方案下炉膛内结渣发生的主要部位与燃用单一煤种时相似。采用两种煤种炉内混烧方案时,中挥发分煤种与高挥发分煤种混烧时炉内结渣情况较好,且将挥发分含量相对较高的煤种从底部给入时,能够有效减轻屏式过热器底部结渣情况;对于3种煤种炉内混烧,入炉位置对侧墙水冷壁结渣有较大的影响,当高挥发分煤种入炉比例为50%时,各位置结渣情况较好。

In order to investigate the influence of co-firing of multiple coals on the slagging characteristics at various positions in the furnace and to optimize the operation of the boiler,this paper establishes a 350MW front and rear wall opposed pulverized coal boiler model,which realizes the tracking of the particles and calculate the deposition rate of the particles on the wall.The results show that the overall slagging situation in the furnace meets the requirements of safe production when burning a single coal type.The main positions of slagging in the furnace under different furnace co-firing schemes are similar to the working conditions of a single coal type.While the two-coal co-firing scheme is adopted,the slagging situation in the furnace is better when the medium-volatile coal and the high-volatile coal are co-fired,and placing relative higher volatile coal at the bottom can effectively lighten the slagging at the bottom of the screen superheater.For the co-firing of three coal types in the furnace,if the proportion of high volatile coal entering the furnace is over 50%,the overall slagging situation is better.The injection position has a greater impact on the slagging of the side wall.