The gas adsorption isotherms of three kinds of coal with different metamorphic degree were measured in the high and low temperature environment, the measured data were fitted by Sips model, and the thermodynamic parameters of gas adsorption were calculated and analyzed, including the enthalpy change, the adsorption free energy, entropy change and so on. The research results showed the value γ that represents the coal surface adsorption uniformity decreased linearly with the decrease of the ambient temperature, i. e. the adsorption heterogeneity enhanced; the negative enthalpy change (ΔH) of gas adsorption indicated that the adsorption was exothermic, and with the temperature decrease, the enthalpy change reduced linearly;the curves of the enthalpy change and temperature of the coal with different metamorphic degree intersected at the point where the temperature was 0 ℃( 273. 15 K ); the negative value of the adsorption free energy (ΔG ) indicated that the gas adsorption on coal was a spontaneous process;with the decrease of ambient temperature, the greater the entropy change (ΔS) , the easier the gas adsorption and the larger the gas adsorption amount.%在高低温环境下测定了3种变质程度煤的瓦斯吸附等温线,并通过 Sips 模型进行拟合,同时对瓦斯吸附的焓变、吸附自由能和熵变等热力学参数进行计算分析,研究结果表明:随环境温度降低,煤表面吸附均一性的γ值线性减小,即吸附不均一性增强;吸附焓变(ΔH)为负值,表明吸附是放热的,且焓变随着温度降低线性减小;不同变质程度煤的焓变—温度线交于温度为0 ℃(273. 15 K)的点;吸附自由能(ΔG)为负值,表明甲烷在煤上的吸附过程为自发过程;随环境温度降低,熵变(ΔS)越大,吸附过程越容易进行,瓦斯吸附量也越大.
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