Abstract
Methane adsorption isotherm experiments on semianthracite (2.00-2.33% [Formula: see text]) collected from the Xin’an coal mine, Henan Province, China, were conducted to investigate the effects of pore structure, coal quality, coal maceral, and coal rank on methane adsorption capacity with applications of univariate and multivariate analyses. Methane adsorption capacity varies significantly from 12.03 to 28.40 cm3/g. In univariate analysis, methane adsorption capacity has a strong positive correlation with pore specific surface area, weak positive correlations with pore volume and ash content, and weak negative correlations with moisture content and inertinite content. No correlation is observed between methane adsorption capacity and coal rank. In multivariate analysis, the mathematical model of methane adsorption capacity affected by the combined individual variables is established based on quantification theory I. There are similarities and differences between the two analyses. The similarities are that pore specific surface area has the greatest contribution to methane adsorption capacity, while coal rank has the least contribution. The differences are reflected in two aspects. Firstly, the other influencing factors contribute differently to methane adsorption capacity. Secondly, the positive or negative correlations of some influencing factors present the opposite. The mathematic model synthetically covers the combined effects of the influencing factors, which is more representative in evaluating methane adsorption capacity.
Highlights
Different from conventional gas resources, coalbed methane (CBM) belonging to unconventional gas resources is retained in coal reservoirs in three different forms, including adsorbed gas, free gas, and dissolved gas [1,2,3,4,5]
This paper examines the variation of methane adsorption capacity and its influencing factors of the No 21 coal in the Xin’an coal mine, Henan Province, China
The observation is consistent with Zou et al [55], where they demonstrated a significant change in methane adsorption capacity of the isorank coals
Summary
Different from conventional gas resources, coalbed methane (CBM) belonging to unconventional gas resources is retained in coal reservoirs in three different forms, including adsorbed gas, free gas, and dissolved gas [1,2,3,4,5]. During underground coal mining, a deeper understanding of methane adsorption capacity is critical to prevent gas-related problems, such as explosive and outburst hazard [14, 15]. These significances make studies on methane adsorption capacity become one of the most valuable topics [16,17,18]. Other parameters of coal property, including coal deformation [29], macromolecular structure or crystallite structure characteristics of coal [37, 38], chemical structure of coal organic matters (e.g., aromatic structure, aliphatic structure, and coal surface functional group) [6, 14, 28, 39], and pore structure characteristics (e.g., pore specific surface area, pore volume, pore size distribution, and fractal characteristics) [7, 28, 30, 40,41,42,43,44], play important roles
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
