Ma Qingshui, Zong Jiayi, Zhang Chao, Wu Xingyu, Jia Tinggui
Guizhou University, Guiyang, China.
Inner Mongolia Mengtai Buliangou Coal Co, Ltd, Ordos, China.
Sci Rep. 2025 Sep 26;15(1):33058. doi: 10.1038/s41598-025-15809-9.
The competitive adsorption behaviour of CH and CO in coalbed methane mining is crucial for the optimisation of CO enhanced coalbed methane recovery (CO-ECBM) technology. In this paper, the giant canonical monte carlo (GCMC) method is used to simulate and study the competitive adsorption behaviour of CH and CO mixed component gases at different temperatures, pressures, water contents and molar ratios. The results showed that: the competitive adsorption capacity of CO was significantly stronger than that of CH, and the increase of its molar ratios could effectively replace CH; The increase of temperature or water contents decreased the heat of adsorption of equivalence of CH and CO as well as the Langmuir parameters a and b, which weakened the adsorption selectivity of CO, but the competitive ad-sorption advantage was still maintained; the competitive adsorption ad-vantages of CH were also maintained. However, its competitive adsorption advantage was still maintained; under the conditions of low pressure and high CO molar ratios, CO had the strongest ability to drive CH; under the conditions of high pressure and low CO molar ratios, the adsorption selec-tivity coefficient of CO to CH decreased the most; there was an upper limit of saturation in the driving of CH by CO, and even if the molar ratios con-tinued to increase, the driving efficiency was still low. There is a sat-uration limit for the substitution of CH by CO, and even if the molar ratios of CO continues to increase, the substitution efficiency is not significantly improved. This study reveals the competitive adsorption mechanism between CH and CO at the mo-lecular level, and provides a theoretical basis for optimising CO-ECBM technology and improving CBM recovery.
煤层气开采中CH和CO的竞争吸附行为对于优化CO强化煤层气开采（CO-ECBM）技术至关重要。本文采用巨正则蒙特卡罗（GCMC）方法，模拟研究了不同温度、压力、含水量和摩尔比下CH和CO混合组分气体的竞争吸附行为。结果表明：CO的竞争吸附能力明显强于CH，其摩尔比的增加能有效置换CH；温度或含水量的增加降低了CH和CO的等量吸附热以及朗缪尔参数a和b，削弱了CO的吸附选择性，但仍保持竞争吸附优势；CH的竞争吸附优势也得以保持。然而，其竞争吸附优势仍得以维持；在低压和高CO摩尔比条件下，CO驱替CH的能力最强；在高压和低CO摩尔比条件下，CO对CH的吸附选择性系数下降幅度最大；CO驱替CH存在饱和上限，即使摩尔比继续增加，驱替效率仍然很低。CO对CH的置换存在饱和极限，即使CO的摩尔比继续增加，置换效率也不会显著提高。本研究揭示了CH和CO在分子水平上的竞争吸附机理，为优化CO-ECBM技术和提高煤层气采收率提供了理论依据。
