为了研究水分对CO₂置换煤中甲烷的影响效应，选择无烟煤作为试验煤样，采用水蒸气吸附法分别配制不同含水率的煤样，通过优化的BET模型计算出煤对水的吸附势能，并展开CO₂，CH₄及混合气体等温吸附试验。结果表明：优化的BET模型可以很好地拟合煤对水蒸气的吸附量；无烟煤对水的一级吸附势能E₁与二级吸附势能E₂分别为44.20 kJ/mol和42.27 kJ/mol，大于煤对CH₄与CO₂的吸附势能，说明水分对煤中气体具有置换作用；相同条件下，CO₂的吸附能力大于CH₄；随着含水率提高，煤吸附CO₂与CH₄的能力逐渐减弱；水分对煤中甲烷的置换效果显著增强；CO₂对煤中甲烷置换量随含水率提高而降低，置换率基本不变，水分对CO₂置换起到抑制作用。

In order to study the effect of moisture on CO₂ displacing methane in coal, a set of isothermal adsorption experiments of CO₂, CH₄ and their mixed gases were carried, and the adsorption potential energy of coal adsorbed water was calculated by the optimized BET model. In this experiment, two highly metamorphic coal samples of fat coal and anthracite coal with different moisture contents were prepared by the water vapor adsorption partition method. The results show that the adsorption capacity of coal to water vapor can be fitted by the optimized BET model. The first-order and second-order adsorption potential energies of anthracite for water are E₁=44.20 kJ/mol and E₂=42.27 kJ/mol, respectively, which are larger than the adsorption potential energies of coal for CH₄ and CO₂, indicating that the water has a displacement effect on gas in coal. The adsorption capacity of CO₂ is greater than that of CH₄ under the same conditions. The ability of coal to adsorb CO₂ and CH₄ gradually decreases with the increase of water content, and the displacement effect of H₂O on CH₄ in coal is significantly enhanced. The displacement of CH₄ in coal by CO₂ decreases with the increase of water content, and the displacement rate is basically unchanged. Moisture plays an inhibitory role in CO₂ displacement.