Variations in Adsorption of Two Step Solvent Extracted Vitrain and Their Coal Crystallites Response

Adsorption capacity and crystallite characteristics of raw vitrains collected from western Guizhou and eastern Yunnan and their step extracted residues were analysed; the possible geochemical mechanism of methane adsorption on coal crystallite was discussed. The results show that the step extraction changes methane adsorption capacity on sample, and the change direction and magnitude depend on the coalification degree. The extraction also depolymerizes the coal crystallite. It is found that it has a synchronous relationship between the percent change of adsorption and the percent depolymerization of coal crystallite. It is suggested that the second coalification jump plays a key role on the percent change of methane adsorption and the percent depolymerization of crystallite. The crystallite depolymerization is an important reason that methane adsorption percent changes.