Shanxi Key Laboratory of Coal and Coal-measure Gas Geology
School of Resources and Environment, Henan Polytechnic University
Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization
Langfang Branch of PetroChina Research Institute of Petroleum Exploration & Development
School of Energy Science and Engineering, Henan Polytechnic University
Yellow River Conservancy Technical Institute

厘定生物产氢后的余煤再产甲烷的有利因素，对于提高煤联产第二阶段甲烷产气效率具有重要的理论和实际意义。以内蒙古白音华露天矿煤为发酵底物，改变通气条件和水力停留时间(HRT)，讨论不同条件下厌氧发酵产氢余煤再产甲烷量和煤结构的动态变化趋势。结果表明：(1) 对比其他气氛条件，CO2组产甲烷效果最好，单位气体生成量为4.72 mL/g，而HRT增加使产气效果逐渐降低。(2) 氢化酶活性与产气量的变化规律具有一致性，反应结束后菌液化学需氧量值(COD)均偏低，认为CO2可促进菌体酶活性增强，使CO2甲烷化过程更明显，而较长的HRT不利于微生物菌群存活，建议在后期的工程实践中，设置较短的HRT工艺条件。(3) 对厌氧发酵后的余煤进行XRD和FTIR监测，发现通CO2后煤的芳香碳层间距最大，煤中一些活性官能团如羧基、羟基等均有所减少，HRT为3 d条件下微晶结构和官能团变化较显著，而随着HRT时间延长，煤结构变化愈加不明显。(4) 通入CO2不仅能提高产气率，还可以改变煤大分子结构和孔隙结构，达到煤层自身的增透、增扩、增渗和增解的目的，实现CO2地质封存和煤层气生物工程的融合。

Determining favorable factors in methane production from residual coal post-biohydrogen production holds great theoretical and practical significance for improving the efficiency of methane production in the second stage of coal-based poly-generation. This study focuses on residual coal after hydrogen generation through anaerobic fermentation. Using coal samples from the Baiyinhua open-pit mine in Inner Mongolia as fermentation substrates, this study explored the dynamic trends of both the methane production and structure of the residual coal under different conditions by altering the aeration conditions and hydraulic retention time (HRT). Key findings are as follows: (1) Among the experiment groups with different atmosphere conditions, the CO2 group exhibited the highest methane production performance, with a unit gas production of 4.72 mL/g. In contrast, the gas production performance gradually decreased with an increase in the HRT. (2) The hydrogenase activity and gas production demonstrated similar laws of change. After reactions, all groups showed low chemical oxygen demand (COD) of the bacterial liquid. It is considered that CO2 can enhance bacterial enzyme activity, leading to a more pronounced CO2 methanation process. Besides, it can be inferred that a long HRT is not conducive to the survival of the microflora. Therefore, a short HRT is recommended the late engineering practices. (3) As discovered by the monitoring of the residual coal after anaerobic fermentation using X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), the coal samples exhibited the largest aromatic carbon layer spacing when CO2 was introduced, with the numbers of some reactive functional groups, such as carboxyl and hydroxyl, in the coal decreasing. Under a HRT of 3 d, the microcrystalline structure and functional groups changed significantly. In contrast, a prolonged HRT corresponded to less pronounced changes in the coal structure. Therefore, injecting CO2 can not only improve the gas production rate but also change the macromolecular structure and pore structure of coal, thus enhancing the permeability, expansion, infiltration, and degradation of the coal seams themselves. Furthermore, the integration of geologic CO2 sequestration and coalbed methane bioengineering can be achieved.

国家自然科学基金项目(42172199)；煤与煤系气地质山西省重点实验室项目(MDZ202102)

夏大平，廖佳佳，陈振宏，等. 生物产氢余煤再产甲烷的有利因素研究[J]. 煤田地质与勘探，2024，52(3)：56−63.

XIA Daping，LIAO Jiajia，CHEN Zhenhong，et al. Favorable factors in methane production from residual coal post-biohydrogen generation[J]. Coal Geology & Exploration，2024，52(3)：56−63.