不同风化程度煤的结构与生物产气效果的变化特征

Variation characteristics of the structure and biological gas production effect of coal with different weathering degrees

为探究风化煤的结构与生物产气效果的变化特征,拓宽风化煤的利用途径,选取内蒙古乌海、山西晋城和太原西山不同风化程度的煤样,以矿井水为菌种来源进行生物产气模拟试验,并从煤的显微组分与官能团方面解释生物产气效果。结果表明:随风化程度加深,煤样镜质组边界与裂隙周围存在的氧化边缘越来越明显,裂隙增大,脂碳、芳碳和羰基的分峰占比下降,芳香结构被破坏,羧基的分峰占比明显增加,含氧官能团的分峰占比整体提升,羧基的分峰占比增加会使产气总量明显增加;煤样受到严重风化后,即使其生物产气总量继续增加,但CH_(4)体积分数可能会出现下降趋势。

To explore the variation characteristics of the structure and biological gas production effect of weathered coal and broaden the utilization ways of weathered coal,the coal samples with different weathering degrees in three coal-producing areas from Wuhai in Inner Mongolia,Jincheng,and Taiyuan in Shanxi province were selected to conduct the biological gas production simulation experiment with the mine water as the source of bacteria.The biological gas production collection device mainly adopted the drainage gas collection method.The device was placed in a 35℃constant temperature incubator,the gas production was recorded every three days,and the volume fraction of CH_(4) in the produced gas was tested.The variation characteristics of macerals and functional groups of coal samples were observed by polarizing microscope and nuclear magnetic resonance spectrometer,and then the biological gas production effect was explained from the macerals and functional groups of coal samples.The results showed that with the deepening of weathering degree,the oxidation edge around the vitrinite boundary and fracture of coal samples became more and more obvious,the surface smoothness of vitrinite became worse,and the fracture increases gradually.With the deepening of weathering degree,the proportion of peak of aliphatic carbon,aromatic carbon and carbonyl decreased gradually,the proportion of peak of carboxyl increased significantly,the aromatic structure was destroyed,and the aromaticity decreased.With the deepening of weathering degree,the volume fraction of CH_(4) showed an overall increasing trend,and the proportion of peak of carboxyl was proportional to the total biogas production,that was,the increase in the proportion of peak of carboxyl would increase the total biogas production significantly.After severe weathering of coal samples,the total biogas production would continue to increase,but the volume fraction of CH_(4) might decrease.The research results provide theoretical reference for reducing environmental pollution caused by weathered coal,improving resource utilization,and establishing biological gas production system of weathered coal.