Effect of H₂O₂ pretreatment combined with anaerobic biodegradation on pore structure of bituminous coal

To study the effect of H2O2 pretreatment combined with biodegradation on coal pores, the bituminous coal was pretreated with 0.05% H2O2, and the high-efficiency methanogenic microflora derived from the produced water of active coalbed methane(CBM) wells was used for anaerobic degradation of coal. The content of biomethane was detected by gas chromatograph and the development of coal pores was characterized by low-temperature liquid nitrogen adsorption. The results showed that H2O2 pretreatment of bituminous coal could significantly enhance biomethane production. Pretreatment had no significant effect on the type of coal pores, but the adsorption capacity of residual coal was reduced, which was conducive to the extraction of in-situ CBM. After pretreatment, the micro-pores and meso-pores volume of coal sample increased, while the transitional pores volume decreased. After biodegradation, the total pore volume and specific surface area of residual coal were significantly reduced; this may be caused by the retention and accumulation of soluble organic matter produced by microbial metabolism in the coal, thus blocking the pores of the coal.