二连盆地吉尔嘎朗图凹陷低煤阶煤层生物产气影响因素

研究低煤阶煤层生物产气的影响因素对于寻找该类煤层生物气富集有利区及指导微生物增产技术都具有重要的意义。为此,选择二连盆地吉尔嘎朗图凹陷褐煤煤样,在不同温度、酸碱度(p H值)、氧化还原电位(Eh值)以及添加不同浓度微量元素等条件下进行了煤的生物气化模拟实验,进而探讨各种因素对微生物产气的影响、确定最佳的微生物产气条件。研究结果表明:(1)在模拟实验条件下,煤的产气量随着温度、p H值、微量元素浓度等参数值的增大或者Eh值的减小而表现出先增大后减小的规律;(2)温度介于30~35℃、pH值介于7.0~7.5、Eh值为-225 m V时,产甲烷菌代谢最活跃,最有利于生物气的生成,添加合适浓度的微量元素(Fe~(2+)、Ni~(2+))能促进微生物产气。结论认为:(1)二连盆地吉尔嘎朗图凹陷埋深介于300~600 m、弱径流的水动力条件与厌氧环境构成了生物气生成的有利条件;(2)添加合适的微量元素可作为微生物增产的有效手段。

Factors influencing the biogenic gas production of low rank coal beds in the Jiergalangtu sag,Erlian Basin

The study on the factors influencing the biogenic gas production of low rank coal beds is of great significance to the search of the favorable biogas enrichment areas of similar coal beds and the guidance of the microbial stimulation technologies. In this paper, the lignite samples taken from the Jiergalangtu sag in the Erlian Basin were selected to carry out the simulation experiment of biogenic coalbed methane under different temperatures, pH values, oxidation-reduction potentials (Eh) and trace element concentrations. Then, the influences on biogenic gas production were discussed and the optimal biogenic gas production condition was determined. And the following research results were obtained. First, in the simulation experiments, the biogas production of coal beds increases first and then decreases with the increase of temperature, pH and trace element concentration and the decrease of Eh. Second, in the case of temperature 30-35 ℃, pH 7.0-7.5 and Eh –225 mV, the metabolism of methanogen is the most active and the most favorable for the generation of biogas, so biogenic gas production can be promoted by adding the trace elements (Fe2+ and Ni2+) of proper concentration. It is concluded that a proper burial depth (300–600 m), a weak runoff hydrodynamic conditionand an anaerobic environment constitute the favorable conditions for the generation of biogas in the Jiergalangtu sag, Erlian Basin. Moreover, the addition of appropriate trace elements can be an effective means of microbial stimulation.