煤热解过程中含氮气相产物转化规律的实验研究

Experimental investigation on the conversion of nitrogenous gas products during coal pyrolysis

为了研究煤在热解过程中含氮气相产物的生成规律,在滴管炉反应系统中对四种原煤以及两种脱除矿物质煤样分别在500℃、700℃、900℃和1100℃进行了实验研究。结果表明,随着温度的升高,作为NO前驱物的HCN和NH3的收率随之增加,N2的收率也增加。煤种对含氮气相产物的生成规律也有着较大的影响,煤化程度比较低的煤在热解过程中,燃料氮向气相含氮产物的转化率较高;煤化程度比较高的煤转化率则偏低,大部分的氮缩聚在多环芳香结构中,成为焦炭氮。煤中的矿物质对燃料氮向N2的转化起到了促进作用,而对燃料氮向HCN和NH3的转化起到了抑制作用。

The conversion of nitrogenous gas products during coal pyrolysis was investigated in the drop tube reactor. Four raw coals and two demineralized coals have been used to pyrolyse at 500℃, 700℃, 900 ℃ and 1 100℃. The pyrolysis results indicate that the yields of N2 and NO precursors, such as HCN and NH3, increase with increased temperature. The coal type has significant effect on the yield of nitrogenous gas products. For low rank coal sample, the conversion ratio of fuel nitrogen is higher. The most of fuel nitrogen in high rank coals is built into condensed aromatic structures to form Char-N. The mineral substances in coal promote the conversion of fuel nitrogen to N2, but they suppress the conversion of fuel nitrogen to HCN and NH3.