Abstract: Under the conditions of high temperature and pressure and equilibrium water, the adsorption-desorption experiments on CH4 were carried out with four destructive type of coal samples in No.12 Mine of Pingdingshan. The experiment results show that the equilibrium moisture of coal samples increase with the increasing extent of the coal damage in the conditions of 50℃. There are some new features on the adsorption-desorption of deformed coal，Langmuir volume of the VL (ash-free basis) first decreases and then increases, and decreases finally. Therefore, the characteristic of results of this adsorption-desorption experiments are due to the combined effects of the unique pore structure of deformed coal and water content. The adsorption-desorption isotherms of deformed coal are irreversible, and this irreversible degree increases with increasing extent of the damage of coal. The data selected by adsorption experiments should not be straightforward used in the desorption experiments on a coal, especially deformed coal.

Key words: deformed coal, adsorption, desorption, high temperature and pressure, equilibrium moisture