Influence of nanoscale pores in coal on methane adsorption

Abstract

In order to study the influence of nanoscale pores ( < 100 nm) in coal on methane adsorption, pore size distribution and maximal methane adsorption capacity of anthracite, meager lean coal, coking coal and gas-fat coal had been studied in the lab. The results show that the macropore volumes of four kinds of coals are developed and they are preponderant in all kinds of pore volumes. The nanoscale pore (less than 100 nm) volume is little in all pore volumes, but the specific surface areas of nanoscale pores ( < 100 nm) of four kinds of coals are developed, and they are more than 95% in total specific area. With the method of curve similarity, the leading factors influencing maximal methane adsorption quantity were analysed. The analysis results indicate that the methane adsorption capacity of coal is dominated by specific surface area of nanoscale pores ( < 100 nm). The methane adsorption capacity of coal increases linearly with the increase of specific surface area of nanoscale pores ( < 100 nm). The maximal methane adsorption quantity decreases in the order anthracite < meager lean coal < coking coal < gas-fat coal.