沁水盆地南部深部煤层超临界CO2吸附特征及其控制因素

为揭示深部煤层超临界CO₂（ScCO₂）吸附特征及其控制机理，以沁水盆地南部余吾矿、寺河矿、成庄矿的3号煤为研究对象，通过自制等温吸附仪进行了不同温度（45℃，62.5℃，80℃）、最高压力达到CO₂超临界压力以上时的等温吸附实验。研究结果表明:高温高压条件下ScCO₂吸附曲线不同于常温常压下CO₂吸附曲线，随压力升高ScCO₂过剩吸附量和绝对吸附量分别呈4段式和3段式变化，ScCO₂达到过剩吸附量峰值出现的压力点具有随温度升高向高压增高的特征；ScCO₂过剩吸附量远低于绝对吸附量，无法采用Langmuir吸附模型进行解释；温度对ScCO₂吸附抑制明显，水分对ScCO₂吸附没有起到抑制作用，灰分含量较高对ScCO₂吸附量有明显抑制作用，煤中高镜质组含量和高R_max对ScCO₂吸附具有较明显的促进作用；超临界状态下煤对ScCO₂的吸附量大小由微孔和过渡孔所控制，且与微孔比表面积大小有关，高变质煤对ScCO₂的吸附能力降低可能是因微孔中矿物充填所致。 

Supercritical CO2 adsorption characteristics and their control factors in deep-seated coal seams in southern Qinshui basin

In order to reveal the characteristics and control mechanism of supercritical CO₂ (ScCO₂) adsorption in deep-seated coal seams, coal No.3 from Yuwu coal mine, Sihe coal mine and Chengzhuang coal mine was chosen as the research object, the isothermal adsorption experiments in different temperature(45℃, 62.5℃, 80℃)were conducted with the maximum pressure above the supercritical pressure of CO₂ by means of homemade isothermal adsorption instrument. The results show that the adsorption isotherm of ScCO₂ under the condition of high temperature and high pressure is different from the adsorption isotherm of CO₂ under normal temperature and pressure. The excess adsorption capacity of ScCO₂ had the variation of 4 sections, the absolute adsorption capacity of ScCO₂ had the variation of 3 sections. The pressure points matched with the maximum on excess adsorption capacity of ScCO₂ had the characteristics of drifting high pressure with increase of the formation temperature. The excess adsorption capacity of ScCO₂ was far below the absolute adsorption capacity of ScCO₂, they couldn't be explained ith the adsorption model of Langmuir. The temperature has an obvious inhibition to the adsorption of ScCO₂, the moisture content has no inhibition to the adsorption of ScCO₂, the high ash content has an obvious inhibition to the adsorption of ScCO₂, the high vitrinite and R_max have a relatively obvious promotion to the adsorption of ScCO₂. The adsorption capacity of ScCO₂ is controlled by micropore and transitional pore, is especially related to the amount of specific surface area from micropore, the decrease on the adsorption ability of ScCO₂ from high metamorphic coal may be caused by filling of the minerals in coal.