深度空气分级对旋风燃烧锅炉NO_(x)释放影响研究

Influence of Deep Air Classification on NO_(x)Release of Cyclone Liquid Slag Removal Boiler

针对纯燃高碱煤旋风液态排渣锅炉局部高温以及NO_(x)排放高等问题,通过ANSYS软件数值研究了不同深度空气分级方案对旋风液态排渣锅炉炉内温度场、组分场及NO_(x)浓度分布的影响。研究结果表明:深度空气分级燃烧不同工况设置合理,形成了良好的富燃料的主燃区与富氧燃尽区,炉内燃烧稳定,旋风燃烧器逆向布置可促进煤粉燃尽,提高锅炉效率。不同深度空气分级工况下,炉内各组分分布特性一致。同时确定了主燃区最佳过量空气系数为0.85,燃尽风量选用逐层降低布置可实现最佳低氮排放,炉膛出口烟温最低为1375.45 K,炉膛出口NO_(x)浓度最低为391.14 mg/m^(3)。

Aiming at the problems of local high temperature and high NO_(x)emission of cyclone liquid slag boiler burning pure high alkali coal.The effects of air classification schemes at different depths on the temperature field,composition field and NO_(x)concentration distribution in the furnace of cyclone liquid slag discharge boiler were numerically studied by ANSYS software.The research results show that:the different conditions of deep air combustion are set reasonably,forming a good fuel⁃rich main combustion zone and oxygen⁃rich burnout zone,the com⁃bustion in the furnace is stable,and the reverse arrangement of the cyclone burner can promote the burnout of pulverized coal and improve the efficiency of the boiler.Under different air classification conditions at different depths,the distribution characteristics of each component in the furnace are consistent.In the meantime,it is determined that the optimal excess air coefficient in the main combustion zone is 0.85,and the optimal low nitrogen emission can be achieved by selecting a layer by layer arrangement of reduced burning air volume.The minimum flue gas temperature at the furnace outlet is 1375.45 K,and the minimum NO_(x)concentration at the furnace outlet is 391.14 mg/m^(3).