高温高压下煤孔隙结构的变化对瓦斯吸附特性的影响

为了研究高温高压条件下煤孔隙结构变化对瓦斯吸附特性的影响，选取九里山矿无烟煤，在压力为7 MPa、温度为40～130℃的条件下进行等温吸附实验和压汞实验。研究结果表明:煤样对甲烷的等温吸附曲线在该压力、温度条件下符合Ⅰ型吸附曲线特性，吸附规律符合Langmuir吸附模型；在压力7 MPa和温度130℃条件下，煤样的孔隙结构发生一定的变化，煤的比表面积增大、累计孔体积降低，可见孔及裂隙的数量比例增高，加强了煤样孔隙之间的连通度，导致原本吸附在煤样表面的甲烷分子大量解吸；在压力不变的情况下，随着温度的不断增高，煤的极限吸附量逐渐减小，其主要原因是样品孔隙结构的破坏和分子间作用力的变化。

Influence of pore structure change on gas adsorption characteristics of coal under high temperature and high pressure

In order to investigate the influence of pore structure change on the gas adsorption characteristics of coal under the conditions of high temperature and high pressure, the isothermal adsorption experiments and mercury intrusion tests were carried out under the conditions of 7 MPa pressure and 40~130 ℃ temperature by using the anthracite of Jiulishan Mine. The results showed that the isothermal adsorption curve of coal sample to methane was in accordance with the characteristics of type Ⅰ adsorption curve under these pressure and temperature conditions, and the adsorption laws conformed to the Langmuir adsorption model. Under the conditions of 7 MPa pressure and 130℃ temperature, the pore structure of coal samples changed, the specific surface area of coal increased, the cumulative pore volume decreased, and the proportion of the visible pores and cracks increased, which strengthened the connectivity between the pores of coal samples, so that the methane molecules adsorbed on the surface of coal samples originally desorbed largely. Under the situation of constant pressure, the higher the temperature, the lower the limit adsorption volume of coal, and the reasons of this phenomenon were the destroy of pore structure in the samples and the change of intermolecular force.