226 / 2024-03-13 19:53:34

Effect of methanol extraction on biological gas production of Shengli lignite

Biogenic coal bed methane, lignite, methanol extraction, methanogenic microorganism, sulfate-reducing bacteria

The utilization of lignite for biological methane production stands as an efficient method for promoting the clean utilization of coal resources. A major challenge in coal biological gas production is the low bioavailability of organic matter within coal. Consequently, enhancing the bioavailability of organic matter in coal through pretreatment has been a primary focus in this field. In this research, we utilized methanol for the extraction of Baiyinhua(BYH) and Mengdong (MD) lignite. The effects of methanol extraction on biological gas production, as well as the physical and chemical properties of lignite, were investigated using GC, SEM, XRD, FT-IR, and Illumina high throughout sequencing for the analysis of microbial community structure and function. The findings indicated that methanol extraction enhanced the microbial hydrogen production rate and initial methane gas production during lignite gas production. Following extraction treatment, methane production from MD and BYH lignite increased, with methane production from MD lignite reaching 330 μmol/g coal post methanol extraction treatment. The methanol extraction process augmented the porosity and fractures of coal, amplified oxygen-containing functional groups and aliphatic hydrocarbons on the surface of lignite, subsequently reducing the hindrances faced by microorganisms in utilizing lignite. In the gas production process, microorganisms converted C=O to C-O, generating more -OH and aliphatic hydrocarbon chains. Following gas production, enrichments of Clostridium sensu stricto 12, Brevibacillus, Geobacter, and various sulfate-reducing bacteria were observed in the methane-producing fermentation solution, with a notably high relative abundance of Desulfosporosinus in MD lignite gas producing system. Furthermore, among the archaea, Methanomassiliicoccus and Methanosarcina exhibited distinct advantages.