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为了研究液态水对煤吸附甲烷影响的机理,进行了不同煤级干燥煤样、平衡水煤样和注水煤样等温吸附实验,基于分子间作用力对液态水影响机理进行分析,并用维里方程拟合等温吸附实验结果来验证.结果表明,煤基质的润湿程度是液态水影响煤吸附甲烷的主要因素.干燥煤样中煤与甲烷分子间作用力远大于甲烷分子间作用力,第二维里系数较低,吸附能力强;平衡水煤样中煤与水分子氢键能高于范德华力,气态水分子竞争吸附,第二维里系数偏高,煤基质吸附能力弱;注水煤样中煤与甲烷分子之间长程作用力和甲烷与水分子之间短程作用力之和较小,与甲烷分子间作用力相当,第二维里系数最高,煤基质吸附能力很低.煤级增高,煤基质表面极性及其润湿程度降低,第二维里系数随之降低.
In order to study the mechanism of the influence of liquid water on methane adsorption by coal, isothermal adsorption experiments of different coal grade dry coal samples, balanced water coal samples and water injection coal samples were carried out. Based on the analysis of the influence mechanism of intermolecular forces on liquid water, The results of fitting isothermal adsorption experiments show that the wetting degree of coal matrix is the main factor that liquid water affects the methane adsorption by coal, the force between coal and methane molecules in coal is much larger than that between methane molecules in dry coal samples, and the second The virial coefficient is lower and the adsorption capacity is stronger; the hydrogen bond of coal and water molecule in equilibrium water-coal sample is higher than van der Waal’s force, the competitive adsorption of gaseous water molecule, the second virial coefficient is high and the adsorption capacity of coal matrix is weak; The long-range interaction between coal and methane molecules and the short-range interaction between methane and water molecules are small, with the same force as methane molecules, the highest coefficient in the second dimension and low adsorption capacity of coal matrix. , The polarity of the coal matrix surface and the degree of wetting decrease, and the second virial coefficient decreases.