Experimental Study on Adsorption-Deformation-Seepage of Co2, Ch4, and N2 in Anthracite

Abstract

The adsorption capacity, deformation, and permeability of coal are the key factors that affect coalbed methane yield and CO 2 geological storage. To explore the adsorption-deformation-seepage mechanism of coal, this paper takes anthracite as the research object and uses the coal rock adsorption-deformation-seepage test platform under multi-physical field conditions to conduct an adsorption-deformation-seepage experimental study of columnar anthracite through the adsorption of CO 2 , CH 4 , and N 2 under stress. The results showed that the adsorption capacity and deformation of anthracite for CO 2 gas were the largest, followed by CH 4 and N 2 . An increase in the adsorption pressure showed an initial decrease and then increase in the permeability of anthracite. The critical pressure points of CO 2 /CH 4 /N 2 gas permeabilities in anthracite were about 2.0 MPa, 1.75 MPa, and 1.5 MPa, respectively. N 2 showed the greatest permeability, followed by CH 4 and CO 2 . Improvements in the dynamic prediction models of adsorption capacity, coal deformation, and permeability based on the law of adsorption-deformation-seepage of coal were established.

Keywords: Anthracite, Adsorption quantity, Deformation quantity, Permeability, CO2/CH4/N2gas