无烟煤微生物成气中间代谢产物组成及其转化

Composition and conversion of intermediate products in the process of anthracite gasification by microorganism

研究了煤生物成气过程中中间产物的变化规律与成气过程的相互关系。以10 kg沁水盆地山西寺河矿的无烟煤为底物,以寺河矿区煤层气井口出水为菌源,进行了煤生物成气模拟实验,利用气相色谱-质谱联用对不同成气阶段发酵液中间产物进行了分析。实验发现煤生物成气有2个主要的产气周期,芳香环、杂环化合物和苯衍生物在反应初期转化为VFA等,发生在第1个产气周期;而长链烷烃的生成有2个高峰期,分别对应2个产气周期。根据煤生物成气模拟实验中间代谢产物的实验结果,进一步选取乙酸钠、丙酸钠、丁酸钠、己酸为底物,仍以同一煤层气井口出水为菌源,进行产气实验模拟,结果显示乙酸、丙酸、丁酸可以产气,而己酸则对成气呈现抑制作用。以底物计算甲烷产生效率为丁酸>丙酸≈乙酸,丁酸约为乙酸和丙酸的4倍;而以碳数计算时甲烷产生效率则为丁酸>乙酸>丙酸,丁酸约为乙酸的2倍,说明不同的有机酸产甲烷时可能存在有机酸碳数奇偶性的差异。以上结果表明,VFA和长链烷烃在煤生物成气中发挥着重要的作用,而有关煤生物成气中VFA和长链烷烃的生成和转化以及其对成气的影响尚需进一步研究。

In order to study the changes of intermediate products in the process of biogenic coalbed methane generation,the simulation experiments were carried out with 10 kg coal from Sihe coal mine in Qinshui Basin as the substrates,and 40 L CBM well water in the same mining area as the bacteria source. The intermediate products in fermentation broth were analyzed using GC-MS. The relationship between the intermediates production and gas production was investigated preliminarily. The results show that there were mainly two periods of gas generation. The conversion of aromatic ring,heterocyclic compounds and benzene derivatives in the substrate into the VFA was found in the first gas generation period. While the high concentration of long-chain alkanes were found in both periods of gas generation.With the sodium acetate,sodium propionate,sodium butyrate,hexanoic acid as the substrate,the same CBM well water as the bacteria source,the process of biogenic methane generation was also investigated. It was found that the acetate,propionate,and butyrate could be converted into methane,while hexanoic acid would inhibit the gas generation perhaps due to its toxicity. The conversions of different organic acids to methane indicated that there were perhaps parity differences in the carbon number of the organic acids. The results above indicate that VFA and long-chain alkanes play important roles in biogenic coalbed methane generation. The production and transformation of VFA and long-chain alkanes and their influences on the biogenic coalbed methane generation need to be further studied.