高温下煤吸附氮气后氧化特性变化的实验研究

Experimental Study on Oxidation Characteristics of Coal Adsorbing Nitrogen at High Temperature

矿井自燃火区注氮气灭火时发现,煤体的温度仍会在高温中维持一段时间,高温下煤样对氮气的吸附影响着煤氧化自燃特性。以锡盟褐煤为研究对象,将煤样分别在200℃下吸附氮气6、12、18 h,通过分析实验煤样的气相产物及氧气消耗,煤氧化表观活化能以及煤孔隙结构参数的变化,研究吸附氮气后煤样的氧化特性。实验表明,煤样经过高温吸附氮气的处理后,气相产物的释放量均高于原煤;高温吸附氮气降低了煤氧化活化能,吸附氮气时间越长,活化能值越低;处理后煤的孔平均直径、孔隙率与渗透率均高于原煤,增加了煤氧反应速率,加快煤氧反应进程。

When nitrogen gas is injected into spontaneous combustion zone, it is found that the temperature of the coal body still maintains at a high temperature for a period of time. The adsorption of nitrogen on the coal at high temperature affects the spontaneous combustion characteristics of coal. In this paper, Ximeng lignite was used as the study object. The gas samples were adsorbed at 200 ℃ for 6 h, 12 h and 18 h respectively. The oxidation characteristics of coal samples after adsorption of nitrogen were studied by analyzing the gasification products and oxygen consumption, the apparent activation energy of coal oxidation and the change of coal pore structure parameters were analyzed. The results show that the release of gaseous products is higher than that of raw coal after high temperature adsorption of nitrogen. The adsorption of nitrogen at high temperature reduces the activation energy of coal, and the longer the adsorption time is, the lower the activation energy is. The average diameter, porosity and permeability are higher than that of coal, which increases the reaction rate of coal and oxygen and accelerates the process of coal and oxygen.