Coalbed Methane Adsorption Related to Coal Properties in Northern and Northwestern China

摘要

Coal adsorption capacity is controlled by temperature, pressure, and coal properties, among which coal properties are the most important. The effects of coal properties on the adsorption capacity of coals from Northern and Northwestern China are investigated in this paper. The experimental data indicate that the relationship between coal adsorption capacity and coal rank appears a reverse U-shaped trend. Coal adsorption capacity changes jumpily during coalification. This change closely corresponds to coalification jumps. Therefore, the coal rank is the most important factor controlling coal adsorption capacity. Coal maceral composition is another controlling factor on coal adsorption capacity. It is obvious that the adsorption capacity of inertinite rich coal is higher than that of vitrinite-rich coal. When the coal is mainly composed of vitrinite (＞90%), the influence of the inertinite is commonly ignored; while the inertinite is higher than 10%, the adsorption capacity is primarily controlled by inertinite. Deformed coal with higher porosity and specific surface area possesses the larger adsorption capacity than any other normal coal.