利用富集培养得到的本源产甲烷菌群对云南昭通褐煤样品进行生物气模拟实验,分析了褐煤生物气生成过程与可能途径。结果显示,为期130d的褐煤生物气生成过程至少经历了两个产气高峰,第一高峰产气率高于第二高峰。本文认为第一高峰期间生气母质主要为褐煤中的腐殖组分,第二高峰期间类脂组和惰质组的微生物降解程度相对增强。甲烷碳氢同位素组成显示,模拟生物气主要通过乙酸发酵途径生成。模拟过程中,甲烷浓度和二氧化碳浓度具有相互消长的变化趋势,甲烷碳同位素组成在模拟后期有变轻趋势,氢同位素则趋于变重,表明模拟过程后期生成的部分甲烷具有二氧化碳还原成因。
Using the parent anaerobic methanogen flora enriched from lignites in the Zhaotong basin, Yunnan, a simulation experiment was carried out in order to analyze the process and possible approach of the biogenic coalbed gas (CBG) generation. Results showed that the process of the biogenic CBG generation in a period of 130 days underwent at least two gas generation peaks with the higher gas generation rate at the first peak than that at the secondary peak. Gas produced during the first peak came mainly from the huminite group and the biodegradation of the inertinite and liptinite groups was strengthened relatively during the secondary peak. Plots of the carbon isotopic composition to the hydrogen isotopic composition of the simulated methane indicated a major approach of the acetate fermentation by which the biogenic methane was generated. During the stimulation process, the methane concentration raised with the drop of the carbon dioxide concentration. Carbon isotopic composition of the methane tended to become lighter and the hydrogen isotope composition to become heavier in the late period of the simulation process. These data indicate the carbon dioxide-reduction of the partial methane generated in the late period of the stimulation.