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

Microbial-enhanced
coalbed methane technology has been found to
promote biomethane production, while the influence of coal rank on
anaerobic degradation remains unclear. This study evaluated the biomethane
potential of anthracite and high-volatile bituminous coal through
comprehensive analyses including gene sequencing, FTIR, XRD, and SEM.
Semiquantitative analysis of molecular structures revealed that anthracite
consisted predominantly of aromatic hydrocarbons, whereas bituminous
coal contained more aliphatic structures. Microbial degradation mainly
affects heteroatomic functional groups and aliphatic structures, showing
limited efficiency in degrading aromatic layer structures. Anthracite
displays a smooth surface microstructure, whereas high volatile bituminous
coal’s rough surface provides more microbial attachment sites.
In high volatile bituminous coal cultures, functional bacteria such
as Enterobacter, Clostridium, and Oscillibacter reached a combined relative abundance of 63.1%,
which increased the variety of organic heterocyclic compounds, organic
acids, and their derivatives in metabolites. These effects ultimately
resulted in a 72.4% higher methane yield from bituminous coal compared
to anthracite. This research provides important insights for accelerating
the engineering application of microbial-enhanced coal-bed methane
technology.