运用试验研究及数值模拟方法，分析了130 t/h四角切圆煤粉炉进行低氮燃烧改造后，空气分级对炉内火焰特性、NOx 排放和灰渣结焦的影响。研究表明：分离燃尽风（SOFA）比率为24.8%时，燃烧器区域的平均燃烧温度下降120 ℃,SOFA风上部的烟气温度上升80 ℃；改造后锅炉NOx 排放量下降了36.4%；CFD数值模拟与NOx 实测排放的相对误差在±5%以内，证明了数值模拟的可靠性；随着SOFA比率的增大，燃烧器上部火焰切圆直径增大,较高温度下灰中结焦液体含量增多，反映了炉内SOFA风上部炉壁更易结焦，这与实际情况相符。

Through a series of experiments and CFD numerical simulations,the influence of air staging on flame behavior,including NOx emission,temperature profiles and slagging,were investigated in a 130 t/h tangentially firing furnace of pulverized coal.The results showed that the average combustion temperature in the burner zone was reduced by 120 ℃ when SOFA wind ratio is 24.8%,but the flue gas temperature increased by 80 ℃ above the SOFA nozzle.The NOx emissions were effectively decreased by 36.4% through the low-NOx combustion retrofit,i.e.,air staging and low-NOx burner.The relative error between CFD numerical simulation and NOx measured emission is less than 5%,the CFD modeling was verified.With the increase of air distribution ratio in SOFA nozzle,the circle diameter of flame increases,which show the trajectories of pulverized coal or ash particles are much more near the wall and cause the slagging.with higher temperature,the liquid level in ash sample increases,indicating it is easier to have slagging near the wall above SOFA,which is consistent with experimental observation.

TK229.63

国家重点研发计划（2018YFB0604202）；上海浦江人才计划（16PJ1407800）；上海高校青年教师培养资助计划（ZZslg16043）