Characteristics and mechanism of adsorbed methane in high rank Ⅲ anthracite

Up to now, there is little research on the methane adsorption characteristics of high rank Ⅲ anthracite. The high rank Ⅲ anthracite from Fujian and West Beijing was used to conduct the methane isothermal adsorption test under the temperature of 30℃.The results show that the adsorption capacity of the high rank Ⅲ anthracite is lower than that of bituminous coal and other high rank Ⅰ, Ⅱ anthracite under the same conditions. Through the analysis of the low-temperature nitrogen adsorption test results, combined with the coal structure theory and previous research results, this paper points out that the unbalance of the pores, the minimum of the specific surface area and pore volume, and the high aromatic condensation degree make the adsorption space of methane greatly decreased, and the adsorption quantity evidently reduced. This paper can enrich and perfect the coal adsorption theory, guide coal mine gas control and the ground CBM exploration and development of high grade Ⅲ anthracite.