Research on adsorption characteristics and adsorption model of CH₄ and CO₂ in Leping Formation coal seam of Fengcheng Mining Area

The gas adsorption characteristic of coal body determines the geological storage capacity of coal seam. Isothermal adsorption experiments were conducted in the main B₄ coal seam in the mining area under different temperature conditions to study the gas adsorption characteristics of the coal seam. Nine different adsorption mathematical models were used to fit and analyze the CO₂ adsorption experimental data, and the fitting effects of different models were tested. The results indicate that: the overall experimental pattern of CH₄ and CO₂ isothermal adsorption in B₄ coal seam of Fengcheng Mining Area shows that the pressure is a positive effect and the temperature is a negative effect; the adsorption capacity of coal seams for CO₂ is significantly stronger than that for CH₄, and the ratio of the maximum adsorption capacity of the two is about 2.0; the L model, T model, LF model, and EL model have the best fitting effect and are most suitable for characterizing the adsorption characteristics of CO₂ in coal seams.