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采用U型管反应系统,研究了氧浓度、气流速率和气化温度对神木煤气化过程中NO_x及其前驱物的释放规律。研究发现:气化时生成的HCN和NH_3总量比热解时大幅下降,表明O_2的引入抑制了H自由基的可获得性。随着氧浓度的增加,NO的收率先减后增,而NO_2收率几乎没有变化。氧浓度较低时,生成的高浓度CO阻止了挥发分氮向NO的转化。气流速率对含氮气相产物释放影响各不相同。低温气化产物以NO_2和HCN为主,NO_2主要来自进样期挥发分的缓慢氧化,而高温气化产物中的NH_3的生成主要来源于焦炭氮。
U-tube reaction system was used to study the release of NO_x and its precursors during the gasification of Shenmu coal during the oxygen concentration, gas flow rate and gasification temperature. The results show that the total amount of HCN and NH_3 produced during gasification is significantly lower than that during pyrolysis, indicating that the introduction of O_2 suppresses the availability of H radicals. With the increase of oxygen concentration, the yield of NO decreases first and then increases, while the yield of NO 2 hardly changes. When the oxygen concentration is low, the high concentration of CO produced prevents the conversion of volatile nitrogen to NO. The effect of gas flow rate on the release of nitrogen-containing gas phase products varies. Low-temperature gasification products are dominated by NO2 and HCN. NO2 mainly comes from the slow oxidation of the volatile components during the injection period, while NH3 in high-temperature gasification products mainly comes from the coke nitrogen.