Study on Difference of Binary Gas Competitive Adsorption of Soft and Hard Coal

The physical properties of soft coal and hard coal in the same coal seam are different, which leads to the difference in gas adsorption behavior. Based on the laboratory test simulation method, this paper tested the difference of physical parameters of soft and hard coal, built a binary gas competitive adsorption experimental platform, and studied the competitive adsorption characteristics of CO₂ and CH₄ of soft and hard coal. The results show that the basic parameters of soft and hard coal are similar except f value, and the pore volume and pore surface area of soft coal are larger than that of hard coal. The adsorption capacity of soft coal is greater than that of hard coal, and the adsorption capacity of CO₂ is greater than that of CH₄. The adsorption capacity of coal for CO₂ of a single component is the largest, and that for CH₄ is the smallest. The total adsorption capacity of coal for CO₂+CH₄ is between the two. As the adsorption equilibrium pressure increases, the adsorption curve of coal on mixed gas will gradually move away from the adsorption curve of coal on CH4 of a single component, but increasingly close to the adsorption curve of CO₂.