过量空气系数对旋风锅炉纯高碱煤燃烧及NO_(x)释放影响特性研究

Effect of Excess Air Coefficient on Combustion and NO_(x) Emission of Cyclone Boiler with Pure High Alkali Coal

针对新型纯燃高碱煤旋风液态排渣锅炉,用数值方法研究了旋风液态排渣锅炉炉内空气动力场、温度场及组分分布特性,揭示了过量空气系数对旋风液态排渣锅炉燃烧及NO_(x)释放特性的影响,确定了最佳过量空气系数。研究结果表明:旋风液态排渣锅炉整体空气动力特性良好,炉内燃烧稳定,颗粒停留时间长;在叶片倾角为30°时,随着过量空气系数α由1.1增加至1.25,炉膛出口烟温逐渐升高,炉膛出口NO_(x)浓度在α=1.25时升高至1026.84 mg/m^(3)。综合考虑,选取过量空气系数α为1.15,此时炉内温度分布合理,颗粒停留时间较长,炉膛出口NO_(x)浓度较低。

In this paper, the distribution laws of the aerodynamic field, temperature field, component field in the cyclone boiler with slag-tap furnace were numerically analyzed.The influence of excess air coefficient on the combustion and NO_(x) emission characteristics of the boiler was revealed, and the optimal excess air coefficient was determined.The results show that the overall aerodynamic characteristics of the boiler is good, the combustion in the boiler is stable, and the residence time of particles is long.With the increase of excess air coefficient α from 1.1 to 1.25,the flue gas temperature at furnace outlet increases gradually, and NO_(x) concentration at furnace outlet increases to 1 026.84 mg/m^(3) with α= 1.25.In summary, the excess air coefficient of 1.15 is optimal.With that, the temperature distribution in the furnace is reasonable, the residence time of particle is relatively long, and the NO_(x) concentration at the furnace outlet is relatively low.