基于煤体赋存环境的厌氧型甲烷氧化菌降解甲烷特征实验研究

Following the discovery of the methanotrops, their anaerobic oxidation mechanism of methane has been revealed gradually, which provides a basic theory of applying microbial means to eliminate methane of coal seam and to effectivelly govern gas disaster during the coal mining. On the other hand, it also brings great challenges from the primary bottleneck problem, which should be actually made clear if the methanotrops can still survive and react on the methane under the actual occurrence condition of coal body. Based on the incubating and the optimization of separation of some type of anaerobic bacteria for the detection of objects, and on the consideration of some influencing with continuous dynamic stress, frequent changes of temperature, the oxygen supply as the feature factors of the occurrence environment in underground coal seam, some coal body specimen will be made and used to be loaded stope stress (load simulation axial pressure and confining pressure), to be adiusted temperature change, and to be controlled of oxygen supply, respectively, a series of experimental study also followed to carry out on the effect of the single factor and comprehensive factor transformation strain growth and degradation of coal methane, carbon dioxide process. In order to make clear the significant growth features of the anaerobic bacteria with methane as the sole carbon source for survival, to master the quantitative parameters characteristics of the methanotrops' growth and their consumption of methane, and of the generation of CO2; obtaining the common law of their direct affection of the degradation process against coal methane adsorption capacity and the indirect influence of the CO2 generation rate on the replacement capacity to the coal's adsorption to the methane. Finally to promote the rapid formation and application of the microbial theory to elimination gas disaster during coal mining.

甲烷氧化菌的发现及其厌氧降解甲烷机理的揭示，为应用微生物手段消除煤体甲烷并有效治理瓦斯灾害提供了基本的理论依据，同时也带来了极大的挑战，其首要的瓶颈难题是该类菌株在采场煤体的实际赋存环境中是否仍能生存和生长。本项目以反复培养、优化分离的厌氧型甲烷氧化菌株为检测对象，以持续的动态应力作用、频繁的温度变化、稀薄的氧气供应为煤体赋存环境的主要特征因素，拟通过在实验室针对原煤煤体（试件）模拟加载采场应力（轴压和围压）、调节温度变化、控制氧气供应，分别开展以上单一因素和综合因素影响下菌株生长及其降解煤体甲烷、转化生成二氧化碳过程的实验研究。以期明确在此条件下厌氧菌株以甲烷为唯一碳源生存、生长的显著性；掌握菌株生长及其消耗甲烷、生成CO2的定量化参数特征；获取降解过程对煤体吸附甲烷能力的直接影响及其终产物CO2生成速率对置换煤体（吸附）甲烷的影响规律；促进微生物消除瓦斯减灾技术体系的快速形成和应用。

本项目针对严重制约煤矿安全生产的瓦斯灾害治理瓶颈难题，有机融合微生物相关理论、技术和分析手段，通过培养、驯化高效能的降解甲烷厌氧微生物混合菌株，利用自主研发定制的模拟实验装置测试、分析煤体赋存条件（不同压力和温度及氧含量等）下，不同浓度厌氧微生物菌液注入煤体后，对煤体甲烷的降解机制、规律、效能及其影响因素，以期为寻求构建一条微生物治理煤矿瓦斯灾害新途径提供关键的理论和技术支撑。选择多个不同地点泥样进行厌氧型甲烷氧化菌的培养与分离，驯化得到降解甲烷能力最强菌株样本；该菌株为革兰氏阴性菌，形态为短杆状；其生长大至可分为迟缓生长期、对数生长期、稳定生长期和衰亡期四个时期，其中6-10天为对数生长期，10-15天为稳定生长期；在温度为25℃、pH值为6.5环境下生长状况最优。实验表明该细菌在纯气相状态下对6MPa以下的压力不敏感；较低的氧气浓度（﹤5%）对该细菌降解甲烷能力影响不大，在较高的氧气浓度时（﹥12%）对该细菌降解甲烷产生较大的抑制作用。对微生物降解甲烷全过程中终产物CO2的生成量进行了检测分析，细菌降解CH4量和生成CO2量之比约为3.12：1，大部分碳元素成就了氧化反应的中间产物和微生物的能量消耗。实体煤注入菌液实验表明，随着菌液注入量与注入压力增加，细菌降解甲烷量增加，甲烷降解量与CO2增量比约为3.32：1。试验表明该细菌在煤体内可生长3天左右，第一天细菌降解甲烷的量占到整个甲烷降解量的71%。本项目比较深入地研究了菌液注入实体煤样后的生长规律、降解甲烷规律等，并通过进行比较细致的井下注液工艺、参数匹配变换等方面的考察和分析，基本形成了一套比较明确的通过微生物降解煤体甲烷理论和可行的治理瓦斯新技术和新工艺。本项目研究成果对推进学科交叉和进一步促进完善煤矿瓦斯灾害治理及煤层气开发、利用理论和技术体系具有较大的现实意义。