Coalification as a Process Determining the Methane Adsorption Ability of Coal Seams

Abstract

The paper presents the results of a study of methane adsorption on coal samples with various degrees of metamorphism, coming from the Polish and Czech parts of the Upper Silesian Coal Basin (USCB). The range of coalification of the samples was from bituminous with vitrinite reflectance Ro equal to about 0.5% to para-anthracite coals with Ro equal to over 2%. The methane adsorption capacity was determined at the temperature 303 K for each of the studied coal seams. Methane adsorption isotherms were approximated using the Langmuir model. The relationship between the Langmuir isotherm parameters (am and PL) and the degree of coalification was presented. It was shown that the degree of coalification of the coal substance affects the adsorption ability of coal with respect to methane and determines the value of the Langmuir isotherm parameters. The study was conducted in order to present the distribution of adsorption capacity of Upper Silesian coals in relation to improving work safety in active mines as well as designing technologies that use coal bed methane (CBM) from balance and off-balance resources.