The main reason for CO enhanced coalbed methane recovery is the competitive adsorption of CO and CH on coal. Therefore, it is necessary to study the equilibrium adsorption of CO, CH and their mixed gases on coal over a wide range of pressures. This work investigates the mechanism adsorption of CO/CH on coal by thermodynamics. The findings indicate that CO demonstrates a greater increase in Gibbs free energy and a larger decrease in entropy loss related to CH, indicating that the adsorption process of CO is more to occur spontaneously. In CO/CH mixed gas adsorption system, the amount of gas adsorbed for different gas ratios (: = 1:3; : = 2:2; : = 3:1) falls between the amounts adsorbed for pure CO and CH components. As CO concentration rises, the amount of mixed gases adsorbed similarly increases. Additionally, the amount of CH adsorbed in any combination is lower than that of CO, suggesting that CO has a predominant influence regarding the adsorption process. Furthermore, isosteric heat of adsorption for CO in the mixed gases exceeds that of CH, suggesting a stronger connection between CO and the surface of the coal matrix during the competitive adsorption stage.

中文翻译：

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CO2/CH4 在煤上的竞争吸附：热力学的见解

CO提高煤层气采收率的主要原因是CO和CH在煤上的竞争吸附。因此，有必要研究煤在较宽压力范围内CO、CH及其混合气体的平衡吸附情况。本工作通过热力学研究了 CO/CH 在煤上的吸附机理。研究结果表明，CO 表现出更大的吉布斯自由能增加和与 CH 相关的熵损失更大的减少，这表明 CO 的吸附过程更容易自发发生。在CO/CH混合气体吸附系统中，不同气体比例（:=1:3；:=2:2；:=3:1）的气体吸附量介于纯CO和CH组分的吸附量之间。随着CO浓度的升高，吸附的混合气体的量同样增加。此外，任何组合中 CH 的吸附量均低于 CO 的吸附量，表明 CO 对吸附过程具有主要影响。此外，混合气体中CO的等量吸附热超过CH，表明在竞争吸附阶段CO与煤基质表面之间的连接更强。