The migration of CH4 and CO2 in Jincheng anthracite coal

Abstract：Base on the experimental tests of effective stress, adsorption swelling and permeabili- ty under triaxial stress, the change of dynamic permeability as a function of applied stress, pore pressure and swelling induced by adsorption were investigated at Jincheng anthracite coal. It was proved that the relation of sorption induced swelling, the pore pressure could be de- scribed by Langmuir style function and the permeability of coal shows negative exponential re- lationship with effective stress as well as sorption induced swelling. Meanwhile, the results show that the swelling rates of anthracite coal with methane and carbon dioxide are different. The former is relatively low with single pore gas diffusion model and the later is relatively high with double pore gas diffusion model. In addition, the initial permeability of coal after saturat- ed adsorption at different pore pressure shows power function relationship with pore pressure. Under the same condition, the permeability of Jincheng anthracite coal was 1. 14-1.51times (the normal one is about 1.30) after adsorbed methane than adsorbed carbon dioxide.