Adsorption mechanism of different coal ranks under variable temperature and pressure conditions

Variable temperature and pressure adsorption tests were conducted on four coal samples with different coal ranks, under simulated temperatures and pressures corresponding to coal reservoirs at different depths. The regularity of the variation in the amounts of adsorption by coals under variable temperature and pressure and 30 ~C isothermal conditions are compared and the adsorption characteristics of coal under the composite effect of temperature and pressure were obtained. The adsorption test and data processing method of coal under variable temperature and pressure are presented and the effect of the mechanism of tempera-ture and pressure on the adsorption capacity of coal has been studied. The research results are of significant importance in the in-vestigation of coalbed methane storage mechanism and for the prediction of the amounts of coalbed methane at various depths.