氧化还原电位对低煤阶煤生物甲烷生成的影响

Impact of oxidation-reduction potential on the generation of biogenic methane in low-rank coals

氧化还原电位(Eh)是煤层生物甲烷生成的重要控制因素之一。为了解其对煤层生物甲烷产出的影响以及产甲烷的动力学过程,在实验室采用-102mV、-153mV、-208mV、-284mV、-315mV这5个氧化还原电位值,对河南义马低煤阶煤样品进行了生物甲烷模拟产出实验,采用气相色谱仪对不同反应阶段生成气体的成分及生成量进行检测,同时对菌种源中微生物进行培养计数。结果表明:①不同Eh条件下的实验均有甲烷的生成,氧化还原电位较低时产甲烷菌的繁殖更加快速,在-284mV时生物甲烷的浓度最大,-102mV时最小;②通过平板计数法,分析了产甲烷过程和细菌生长动力学机理——整个产甲烷生成过程也是微生物生长代谢的过程,间接证明了产气量大小变化的原因。结论认为,Eh对于煤层生物甲烷的生成具有重要的控制作用。

Oxidation-reduction potential(Eh) is one of the important factors that controls the generation of biogenic methane in coal beds.In order to know better that impact and the kinetic process of methane generation,we adopted 5different Ehvalues of-102,153,-208,-284,-302mV under laboratory conditions;then made a simulation test on the low-rank coal samples from the Yima,Henan Province.After that,the components and volume of the generated gas at different reaction stages were detected by use of gas chromatography,meanwhile the microbes in the strains were cultivated and counted in numbers.The following results were achieved.(1) Methane was generated under different Ehconditions;the lower the Eh value,the more rapidly the reproduction of methanogens developed;the concentration of biogenic methane was the highest when the Ehvalue was-284mV,the lowest when the Ehvalue was-102mV.(2) The plate count method was used to analyze the kinetic process of methane generation similar to that of bacteria growth and metabolism,which gave an indirect evidence for the reason of the fluctuation of the biogas generation volume.In the end,it is concluded that the Ehplays an important controlling role in the generation of biogenic methane in coal seams.