Comparison of Biodegradation Mechanisms and Structural Evolution Characteristics between Anthracite and Bituminous...

Area of Science:

• Geochemistry
• Microbiology
• Energy Science

Background:

• Microbial-enhanced coalbed methane (MECM) technology boosts biomethane production.
• The effect of coal rank on anaerobic degradation for MECM is not well understood.

Purpose of the Study:

• To evaluate the biomethane potential of anthracite and high-volatile bituminous coal.
• To elucidate the influence of coal rank on microbial anaerobic degradation.

Main Methods:

• Comprehensive analyses: gene sequencing, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM).
• Semiquantitative analysis of molecular structures and surface microstructures.
• Metabolite analysis of microbial cultures.

Main Results:

• Anthracite is rich in aromatic hydrocarbons with a smooth surface; bituminous coal has more aliphatic structures and a rougher surface.
• Microbial degradation primarily targets heteroatomic functional groups and aliphatic structures, with limited efficacy on aromatic structures.
• Bituminous coal cultures showed a higher abundance of functional bacteria (e.g., Enterobacter, Clostridium, Oscillibacter), leading to increased organic heterocyclic compounds and organic acids.

Conclusions:

• Coal rank significantly influences MECM by affecting coal structure and microbial activity.
• Bituminous coal's characteristics favor microbial degradation, resulting in substantially higher methane yields compared to anthracite.
• Findings offer critical insights for optimizing MECM technology applications.