论文部分内容阅读
在不同磨煤机组合运行方式下,对一台1 000 MW超超临界前后墙旋流对冲燃烧煤粉锅炉进行了炉内流动、燃烧、传热与NOx排放特性数值模拟研究。模拟结果与试验测量值符合性较好。结果表明,不同的磨煤机组合运行方式对煤粉颗粒在炉膛内的停留时间、燃烧器区域空气分级效果、下炉膛出口烟气温度和水冷壁壁面热流分布有不同的影响。相比6台磨煤机运行,当5台磨煤机运行,停运上层燃烧器时,煤粉颗粒停留时间增加,飞灰含碳量降低,煤粉燃尽率增加;燃烧器区域空气分级效果得到强化,NOx排放量降低;下炉膛出口烟气温度降低,有利于降低大屏过热器挂渣的倾向。
Under different coal mill operation modes, numerical simulation of flow, combustion, heat transfer and NOx emission in a 1 000 MW ultra-supercritical front-rear wall swirling pulverized coal-fired boiler was carried out. The simulation results are in good agreement with the experimental measurements. The results show that different combinations of pulverizers have different effects on the residence time of pulverized coal particles in the furnace, the air classification effect at the burner zone, the flue gas temperature at the exit of the furnace and the heat flow distribution on the wall. Compared with the operation of 6 pulverizers, when 5 pulverizers are operating and the upper burners are shut down, the residence time of the pulverized coal particles increases, the carbon content of the fly ash decreases, and the burnout rate of the pulverized coal increases; the air quality of the burner area The effect is strengthened, the NOx emission is reduced; the flue gas temperature at the lower furnace outlet is decreased, which is favorable for reducing the tendency of the large-screen superheater to hang dross.