Microorganism Diversity During Generation Of Methane From Low Rank Coal In Xinjiang And Optimization Of Methanogenic Conditions

Xinjiang is one of the most abundant coal resources in china. Under the action ofauthigenous microorganism, the coal can produce methane. It is very significant in improvingthe energy structure and guaranteeing the safety of national energy in Xinjiang. In this paper,we evaluated the effect of low rank coal authigenous microorganism on methane conversionand organic acid content by anaerobic culture. The dynamic changes of microbial communitywere analyzed by Terminal Restriction Fragment Length Polymorphism (T-RFLP) in Hami，slong flame coal. At the same time, we took experiment of methane coversion in Hami’s longflame coal, through changing the methane production conditions, the effects of different pHvalue, temperature and coal size, the optimization of methanogenic conditions was studied byorthogonal experiment. The results are as follows:Analyzed and compared methane and organic acid content by anaerobic culture from lowrank coal in Xinjiang. The results suggested that long flame coal and brown coal had littleinfluence on methane production of authigenous microorganism. As low rank coal biologicalmethane conversion time went on, methane production showed an increasing tendency. Theyield of long flame coal biological methane was up to10.28mL/g and the concentration ofvolatile fatty acid (VFA) was the lowest at60days.The bacterial, archaea and methanogens community diversity of biological methaneconversion were analysized by double fluorescence labeling terminal fragment lengthpolymorphism (T-RFLP) method in Hami’s long flame coal.The results revealed that the majormicrobial groups were Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria in differentlow rank coal conversion periods; Based on the archaea community diversity of biologicalmethane conversion, the results suggested that the diversity indexes of archaea was remainedincrease with low rank coal biological methane conversion time went on. Of these,Crenarchaeota and Euryarchaeota were the advantage group. The bacterial communitystructure was more complex, while the methanogens community structure was relativelysimple. All samples harbored these phyla such as Methanosarcina, Methanohalobium, Methanolobus, Methanomethlovorans. But the dominant group differed in species andabundance in different areas different methane conversion period,which constituted a basicflora of community structure.Through changing the methanogenic conditions, the effects of different pH value,temperature and coal size, the influence of the optimized methanogenic condition were studiedby orthogonal experiment: temperature of the highly factor, coal size of the significant, pHvalue of the less significant. At the same time, we can get the optimized methanogeniccondition: the temperature for38°C, the200mesh for the coal size, the7.4for the pH value.