矿井乏风对锅炉燃烧特性影响

Effect of mine ventilation air methane on combustion characteristics of a coal-fired boiler

对某2 027 t/h四角切圆燃煤锅炉采用矿井乏风作为一次风和二次风的燃烧工况进行数值模拟,在验证模型可行性的基础上,研究了乏风中甲烷体积分数对炉膛温度以及NOx排放的影响。结果表明:随着乏风中甲烷体积分数的增加,炉膛内燃烧区平均温度最大增加53 K;炉膛中氧体积分数和NO质量浓度及煤粉燃尽率随着乏风中甲烷体积分数的升高而降低,而CO变化趋势相反;炉膛出口NO平均质量浓度从388.21 mg/m3降低至318.88 mg/m3,降低幅度达到17.80%。使用矿井乏风作为锅炉一次风和二次风能够有效降低NOx的排放。

The effect of applying mine ventilation air methane as primary and secondary air on coal combustion was numerically studied for a 2 027 t/h tangentially coal-fired boiler.After verifying the feasibility of model,the influences of volume fraction of the ventilation air methane(VAM)on furnace temperature and emission characteristics of NOx were investigated.The results show that,with an increase in volume fraction of the methane in the air,the average temperature in the main combustion zone increased by 53 K at the most,while the concentration of NO and O2 in the furnace and burnout rate of the coal decreased.The CO concentration changed in the opposite.The average concentration of NO at the furnace outlet decreased from 388.21 mg/m^3 to 318.88 mg/m^3,by 17.8%.It can be concluded that applying mine ventilation air methane as primary and secondary air of the boiler can reduce the NOx emission effectively.