O_2/CO_2气氛中低氧浓度下煤粉和煤焦的NO生成规律

NO forming rules in O_2/CO_2 atmosphere of pulverized coal and char with low oxygen concentrations

在石英固定床反应器上,分别考察了O2/CO2和O2/N2浓度比对山西褐煤挥发分氮和煤焦氮向NO转化的影响以及CO浓度对煤焦的NO生成特性的影响。结果表明:O2浓度为15%时,O2/CO2气氛中煤粉的NO释放峰值下降且峰值出现时间提前,而煤焦的NO生成规律受气氛变化的影响较小;随O2浓度的升高,NO累积量先升高后降低;O2/N2气氛下NO累积量逐渐升高;O2/CO2气氛对于抑制煤粉的NO排放具有较好的效果,并且随O2浓度的升高,O2/CO2气氛对煤焦的NO抑制效果逐渐升高;在O2/N2气氛下随O2浓度的升高,煤焦氮的贡献率逐渐升高,O2/CO2气氛中煤焦的贡献率始终大于O2/N2气氛下;O2/CO2气氛中,加入1.5%的CO后,NO的累积量相对未加入CO时降低了14.1%。

Combustion experiments of Shanxi lignite were carried out on a horizontal furnace.The results show that the peak of NO falls and peak value shifts to an earlier time for coal in O2/CO2 atmosphere at O2 of 15% while the NO evolution rules are less affected by the variation of atmosphere.The cumulative emission of NO increases with increasing O2 concentration and then decreases,while in O2/N2 atmosphere,the cumulative emission of NO increases gradually.The O2/CO2 atmosphere is more effective for inhibiting the evolution of NO of pulverized coal and the inhibition effect of NO formation of char is gradually enhanced with the O2 concentration increased.With increasing concentration of O2,the contribution of char nitrogen for NO formation in O2/N2 atmosphere is increasing gradually.The addition of CO on NO formation effect is remarkable as the lowest NO formation with CO involved is reached when the concentration of CO is 1.5%,with the cumulative emission of NO drops by 14.1%.