为阐明煤的大分子结构特征及其在生物产气过程中的变化,选择内蒙古锡林郭勒盟乌兰图噶矿区的褐煤进行生物产气实验,通过13C-NMR测试、元素分析、X射线光电子能谱测试研究其结构变化特征。结果表明:原始乌兰煤样的芳香结构基本单元由3个苯环、3个萘环、1个蒽环和3个吡咯组成,碳原子总数为129个。经过微生物的生物产气作用,碳原子总数减少了21个,其中芳香族碳减少了4个,脂肪族碳减少了17个。原始乌兰煤样大分子结构中的脂肪碳原子为55个,生物产气结束后,脂肪碳数量减少了21.8%,亚甲基碳数量减少了25%,次甲基碳和季碳数量减少了16.7%,氧接脂碳和甲基碳数量分别减少了14.3%和33.3%。煤大分子的芳香结构基本单元和侧链脱落主要发生在水解阶段,在后期产甲烷阶段,煤的结构改造基本停止,仅依靠已脱落于反应液中的物质参与生化反应,这证实了在生物产气过程中,煤大分子结构向更高芳构化程度转化是一个显著的趋势。

To elucidate the structural characteristics of coal macromolecules and their  changes during the biogas production process, lignite from the Ulan Tuhugai mine area in Xilin Gol  League, Inner Mongolia, was selected for biogas production experiments.  The structural evolution  characteristics were studied through  C-NMR, ultimate analysis, and X-ray photoelectron spectros‐ copy (XPS).  The results show that the aromatic structural units of the original Ulan coal sample con‐ sist of 3 benzene rings, 3 naphthalene rings, 1 anthracene ring, and 3 pyrroles, with a total of 129  carbon atoms.  After the biogas production action of microorganisms, the total number of carbon  atoms decrease by 21, of which the number of aromatic carbons decrease by 4, and the aliphatic car‐ bons decrease by 17. The original Ulan coal sample’s macromolecular structure contains 55 aliphatic  carbon atoms.  After the biogas production ended, the number of aliphatic carbon decreases by  21. 8%, the number of methylene carbon decreases by 25%, the number of methylidene carbon and  quaternary carbon decreases by 16. 7%, and the number of oxygenated aliphatic carbon and methyl  carbon decreases by 14. 3% and 33. 3%, respectively.  Stage analysis of the macromolecular structure  of Ulan coal samples indicates that the detachment of the aromatic structural basic units and side  chains of coal macromolecules mainly occurs during the hydrolysis stage.  In the later methane produc‐ tion stage, the structural transformation of coal basically stops, relying only on the substances that  have already detached into the reaction liquid to participate in biochemical reactions.  It is confirmed  that during the biogas production process, the transformation of coal macromolecular structure  towards a higher degree of aromatization is a significant trend.