Adsorption Dynamics Characteristic of Tectonic Coal in Yuwu Coal Mine

Aiming at the methane adsorption dynamics characteristics of tectonic coals, Yuwu Coal Mine of Lu’an Group in Shanxi Province was chosen as the engineering background. Four tectonic coal samples with different degrees of destruction were selected for high-pressure mercury intrusion porosimetry and methane isothermal adsorption experiments, and the pore distribution characteristics in coal and methane adsorption dynamics curves were obtained. The changing laws of adsorption pressure, adsorption volume and adsorption speed with time were analyzed. The research result shows that the adsorption pressure is decreased with the increase of time. At the initial 20 min of the adsorption, pressure sharply declines with the decreasing amplitude, more than 60%. As the increase of adsorption time, the methane adsorption volume experiences a nonlinear changing process: dramatical increase-slow rise-reaching equilibrium. The adsorption speed curves indicate that both the methane adsorption speed and adsorption capacity are enhanced with the increase of the degree of destruction. The pore distribution characteristics of tectonic coals with different destruction types vary a lot, further affecting the methane adsorption dynamics, which should be considered in the engineering practice for coalmine gas control and methane exploitation.