CBM storage character of lignite and gas content estimate method

In the lignite matrix,the porosities are mainly meso-and macroporosities.Experiments show that the adsorption capacity of lignite is low.The free gas in the lignite matrix is more than 50 percent of total gas.Therefore,the conventional gas content measurement is invalid to lignite.The gas content measurement for lignite has been established in this paper,joining the free gas content to the adsorption gas content at the same temperature,the total gas content isotherm can be obtained.The gas content value at same temperature but different pressure can be obtained with this isotherm.