Biogasification of methanol extract of lignite and its residue: A case study of Yima coalfield, China.

To investigate the biogas generation characteristics of the organic matter in lignite, methanol extraction was conducted to obtain the soluble fraction and the residual of lignite, which were subsequently taken as the sole carbon source for biogas production by a methanogenic consortium. Afterward, the composition of compounds before and after the fermentation was characterized by UV-Vis, GC-MS, and HPLC-MS analysis. The results indicated that the methanogenic microorganisms could produce H2 and CO2 without accumulating CH4 by utilizing the extract, and the methane production of the residue was 18% larger than that of raw lignite, reaching 1.