Work

Characterisation of competitive adsorption of CH4 and CO2 mixed components in a coal body based on molecular simulation

Year: 2025

Type: article

Abstract: The competitive adsorption behaviour of CH 4 and CO 2 in coalbed methane mining is crucial for the optimisation of CO 2 enhanced coalbed methane recovery (CO 2 -ECBM) technology. In this paper, the giant canonical monte carlo (GCMC) method is used to simulate and study the competitive adsorption behaviour of CH 4 and CO 2 mixed component gases at different temperatures, pressures, water contents and molar ratios. The results showed that: the competitive adsorption capacity of CO 2 was significantly stronger than that of CH 4 , and the increase of its molar ratios could effectively replace CH 4 ; The increase of temperature or water contents decreased the heat of adsorption of equivalence of CH 4 and CO 2 as well as the Langmuir parameters a and b, which weakened the adsorption selectivity of CO 2 , but the competitive ad-sorption advantage was still maintained; the competitive adsorption ad-vantages of CH 4 were also maintained. However, its competitive adsorption advantage was still maintained; under the conditions of low pressure and high CO 2 molar ratios, CO 2 had the strongest ability to drive CH 4 ; under the conditions of high pressure and low CO 2 molar ratios, the adsorption selec-tivity coefficient of CO 2 to CH 4 decreased the most; there was an upper limit of saturation in the driving of CH 2 by CO 2 , 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 4 by CO 2 , and even if the molar ratios of CO 2 continues to increase, the substitution efficiency is not significantly improved. This study reveals the competitive adsorption mechanism between CH 4 and CO 2 at the mo-lecular level, and provides a theoretical basis for optimising CO 2 -ECBM technology and improving CBM recovery.

Source: Scientific Reports

DOI: 10.1038/s41598-025-15809-9

Authors: Qingshui Ma, Jiayi Zong, Chao Zhang, Xingyu Wu, Tinggui Jia

Institutions: Guizhou University, Inner Mongolia University of Science and Technology

Language: English

Topic: Coal Properties and Utilization

Subfield: Ocean Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $2,690