无烟煤孔隙结构特征及其吸附特性研究

Study on Anthracite Pore Structural and Adsorptive Features

选取焦作矿区无烟煤四种不同煤体结构煤作为研究煤样,通过低温液氮吸附实验,分析了不同煤体结构煤的孔隙结构分布特征,同时对所采集的煤样分别进行高温高压平衡水分条件下CH_4气体的等温吸附实验,分析了孔隙结构、平衡水分与CH_4吸附特性之间的作用关系。研究结果表明:与原生结构煤相比,构造煤的BJH总孔容、微孔比表面积、BJH总孔比表面积随着破坏程度增大而增大。高温高压平衡水分条件下,无烟煤不同煤体结构煤表现出了吸附能力新特性,即随无烟煤破坏程度增加,朗格缪尔体积V_L呈现先增大后减小的变化趋势。不同煤体结构煤的孔隙结构由于构造应力作用而发生变化,引起平衡水分含量的不同,从而导致对CH_4的吸附能力不同。分析表明,无烟煤不同煤体结构煤表现出的吸附新特性,是特有的孔隙结构和平衡水分含量差异综合作用的结果。在不同的埋藏条件下,某一因素会占主导作用,吸附增量变化取决于主控因素控制。

Taking samples from four different coal mass structural anthracites in the Jiaozuo mining area as subject investigated,through low temperature liquid nitrogen adsorptive experiment,have analyzed different coal mass structural coal pore structure distribution features. Meanwhile,to acquired coal samples carried out CH4 isothermal adsorption experiment under high temperature,high pressure and equilibrium moisture conditions respectively; analyzed actions relationships between pore structure,equilibrium moisture and CH4 adsorptive features. The result has shown that comparison with primary structural coal,the BJH total pore volume,micropore specific surface area and BJH total pore specific surface area of tectonoclastic coal increasing along with destructiveness increasing. Under the high temperature,high pressure and equilibrium moisture conditions,different coal mass structural anthracites displayed new features of adsorptivity,i. e. with destructiveness increasing,the Langmuir volume VLhas a trend of increasing first then decreasing. Pore structure of different coal mass structural coals due to structural stress action varied,caused equilibrium moisture content different,resulted in different CH4 adsorptivity. The analysis has shown that different coal mass structural anthracites new features displayed are the results of specific pore structure and equilibrium moisture content difference combined action. Under different buried conditions,a particular factor may play the dominant role; adsorption increment variation rests with main control factor.