| The microbial enhance the production of coalbed methane technology uses anaerobic microbial degrade coal to produce methane,and the bio-transformation of coal in situ in the coal seam.It can not only increase the production coalbed methane,but also extend coal mine gas well service life,and can improve coal seam permeability and increase recovery ratio.It has the advantages of green,pollution-free,low energy consumption and so on,and has a broad application prospect.However,there are many studies on increasing the production of coalbed methane from the perspective of bacteria.And there are relatively few studies on the anaerobic degradation of coal in situ by fungi,but fungi have a natural advantage in the degradation of complex organic matter,which can produce methane combine with methanogens in the rumen.In this article,anthracite from Qinshui Basin was taken as the research object,and the fungal community in situ was cultivated by means of generation and enrichment.The influence mechanism of culture conditions on the anaerobic degradation of coal was analyzed.From the four aspects of microbial composition,crystal structure,intermediate product during the different reaction time,analysis the function of in-situ fungi in anaerobic degradation coal,study the metabolism of fungi in anaerobic degradation of coal.The mechanism of methane production by anaerobic degradation of coal in Qinshui Basin is analyzed,which lays a foundation for understanding the mechanism of anaerobic methane production in situ,and provides a basis for the production of methane from accelerated biodegradation coal,which is helpful for the development of microbial enhanced coal bed methane technology.The results of the study are as follows:(1)The result of enrichment culture showed that the best culture conditions of fungi flora were temperature 35 ?,pH=8,salinity 0.5%,particle size 0.075~0.150 mm and solid-liquid ratio 1:30.The maximum methane yield under this condition could reach 237?mol/g coal.And the ability of fungi degradation of high-rank coal is superior to that of low-rank coal.After being exposed to oxygen for a short period of time,it can still maintain strong activity.(2)Miseq sequencing results showed that the fungi community is dominated by the Ascomycota at the gate level,the main types of archaea community is Methanocella,and that metabolic type is thermophilic hydrogenotrophic.(3)XRD results showed there is a certain swelling effect after fungal reaction,which makes the whole crystal structure of anthracite become more loosen.At the same time,as the reaction continues,the aromaticity of coal decreased after treatment,that is,fungi could effectively destroy the aromatic ring structure of coal,so as to effectively utilize aromatic organic matter in coal to produce methane.(4)FTIR results showed that the stretching vibration intensity of the characteristic peaks of each functional group in coal shows a decreasing trend as the reaction progresses continuously.And the change of the mono-substituted benzene in aromatic functional groups is more obvious than that of the complex functional group.In the oxygen-containing functional group,the stretching vibration strength of the oxygen-containing functional groups in aliphatic is stronger than aromatic oxygen-containing functional groups.In the aliphatic functional group,after the biodegradation,the stretching vibration strength of the side chain functional groups is significantly weakened(5)GC-MS results showed that the intermediates of the reaction mainly contained aromatic compounds,alkanes,alcohols,esters,acids and heterocyclic compounds.Among them,alkanes and alcohols were gradually decreasing with the reaction.The relative percentage of aromatic compounds in the reaction has no significant change during the reaction time,but the abundances of the corresponding aromatic compounds gradually decrease with the reaction,indicating the aromatic compounds in the coal were gradually degraded and utilized. |
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