深部煤层无烟煤甲烷吸附特性研究

Study on methane adsorption characteristics of anthracite in deep coal seam

为了研究深部煤层无烟煤的甲烷吸附特性,利用高温高压煤的吸附试验模拟深部煤层所处的高温高压环境,测得无烟煤软、硬煤在不同温度(40、70、110℃)下的瓦斯吸附常数,采用吸附势理论计算出软、硬煤在不同条件下的吸附势特征曲线,分析了高温高压深部煤层下的甲烷吸附特性;基于压汞法测试高温高压吸附试验前、后的无烟煤软、硬煤的孔隙结构参数,研究了不同温度下深部煤层无烟煤软、硬煤的孔隙结构的变化对甲烷吸附的影响。研究结果表明:无烟煤软煤的微孔孔隙结构较硬煤发达,甲烷极限吸附量大,有利于甲烷的吸附;高温高压吸附试验前后煤的吸附特征曲线呈递减趋势,煤样的吸附势随着吸附空间的增大而减小;高温高压下无烟煤软、硬煤的总孔体积增大、孔隙连通度低于原煤,其煤孔隙向更致密方向发展。

In order to study the deep coal bed methane adsorption characteristics of anthracite, using high temperature and high pressure of coal adsorption test to simulate the deep coal seam environment, we measured soft and hard anthracite coal at different temperatures(40 ℃, 70 ℃, 110 ℃) of the gas adsorption constant, calculated the adsorption potential characteristic curve of the soft and hard coal under different conditions by adsorption potential theory, and analyzed methane adsorption characteristics of the deep coal seam under high temperature and high pressure;we tested the pore structure parameters of soft and hard anthracite before and after the high temperature and high pressure adsorption test based on mercury injection method, and studied the influence of the change of pore structures of soft and hard anthracite in the deep coal seam at different temperature on methane adsorption. The results show that the structure of porous of soft anthracite is more developed than that of hard coal. The adsorption characteristic curve of coal before and after the high temperature and high pressure adsorption test shows a decreasing trend, and the adsorption potential of coal sample decreases with the increase of adsorption space. Under high temperature and pressure, the total pore volume of soft and hard anthracite coal increases and the porosity connectivity is lower than that of raw coal.