CBM resources potential and physical characteristics of coking coal in China

The estimated CBM resources of coking coal within the 2000 m nationwide are 1.214 7×10¹²m³, accounting for about 3.3% of the total CBM resources, and mainly distributed in North, Northwest and Southwest China. In order to evaluate the CBM resources potential of coking coal reservoirs, the data of coal petrography, properties, proximate analysis, mercury injection experiments and isothermal adsorption experiments of coking coal samples from main coking coal mining areas were collected or tested. The results indicated that the content of carbon increased and the content of V_daf, oxygen and hydrogen decreased with the increasing coalification. The reduced rate of oxygen was more rapid than that of hydrogen; The macropore, keyhole and micropore were developed better, mesopore was poorly developed; the specific surface was focused on keyhole and micropore. The porosity and the total pore volume of coking coal increased with coalification, showing relationship of "U" shape. When R_max varied from 1.20% to 1.40%, the porosity and total pore volume decreased with the increasing coalification, While the R_max varied from 1.40% to 1.70%, the porosity and total pore volume increased; The average maximum adsorption capacity was about 20.79 cm³/g, P_L decreased with the increasing coalification, and V_L increased with the increasing coalification.