空气导流板对天然气燃烧器降低排放的影响

Impact of air deflectors on emission reduction of natural gas burner

采用数值方法模拟了14MW天然气燃烧器的燃烧性能,分析了加装空气导流板后,过量空气系数在1.05、1.10、1.15、1.20、1.25时,炉膛内的速度场、温度场,研究了空气导流板和过量空气系数对降低NOx排放的影响。结果表明:配有空气导流板的燃烧器的炉膛内产生了中心回流区,温度梯度变小,切向速度峰值增大,炉膛尾部NOx排放量由58mg/m^(3)下降至50.61mg/m^(3),降低了12.7%;在本文的研究范围内,加装空气导流板的燃烧器随着过量空气系数的增加,炉膛尾部NOx排放量开始有逐渐减小的趋势,在过量空气系数为1.15时达到最低值37.56mg/m^(3);然而当过量空气系数大于1.20时,炉膛内开始出现火焰贴壁现象,不再有利于降低NOx排放量。

The combustion performance of the 14MW natural gas burner is simulated by numerical method,and the velocity field and temperature field in the furnace are analyzed when the excess air coefficient is 1.05,1.10,1.15,1.20 and 1.25 after adding an air deflector.The effect of air deflector and excess air coefficient on emission reduction is investigated.The results showed that a central reflux zone is formed in the furnace of the burner equipped with air deflectors,the temperature gradient becomes smaller,the peak value of the tangential velocity increases and the emission at the exit of the furnace decreases from 58mg/m~3 to 50.61mg/m~3 by 12.7%.Within the research scope of this paper,with the increase of the excess air coefficient of the burner installed with the air deflector,the NOxemissions of the furnace exit begin to gradually decrease and reaches the lowest value of 37.56mg/m~3 when the excess air coefficient is 1.15.However,when the excess air coefficient is greater than 1.20,the phenomenon of flame adherence begins to appear in the furnace,which is no longer beneficial to reduce emissions.