灵武与庆华烟煤显微惰质组富集物的分子结构模型化及对比分析

Molecular structure modeling and comparative analysis of macerals inertinite concentrates from Lingwu and Qinghua bituminous coals

  • 摘要: 从原子分子尺度阐明煤炭微观分子结构和化学键合特征是实现煤炭全元素高效清洁转化 的理论基础。 其中煤炭分子模型构建及分析是透彻理解煤炭微观结构和反应的重要方法。 相对煤 镜质组显微组分,目前对惰质组的研究重视程度不足。 本工作采用元素分析、XRD、XPS、FT-IR、 13 C-NMR 等现代材料表征方法结合分子模拟技术,对庆华煤和灵武煤 2 种宁夏烟煤惰质组富集物 的分子结构进行了表征、建模和对比分析。 研究确定了 2 种煤的化学结构特征,构建了惰质组分子 结构模型:庆华煤C255H179N3O14S和灵武煤C244H170N4O46。 计算和实验的光谱验证整体拟合程度较 好,表明构建的分子结构合理。 结果显示,庆华煤惰质组的变质程度高于灵武煤惰质组,2 者中芳 香基本单元均含有苯、萘、蒽、菲,庆华煤由于较高变质程度还含有芘、苯并a蒽和稠二萘。 2 者脂 肪结构主要由脂肪环,氧接脂肪环以及少量的烷基侧链构成。 其中灵武煤惰质组的含氧量高,导致 氧接脂肪环的数量远大于庆华煤惰质组,分子结构也更为复杂。 随着变质程度的加深,微晶尺寸逐 渐增大,煤的层间距减小,芳香层不断凝聚,微晶结构趋于石墨化。 这些发现揭示了 2 种烟煤惰质 组富集物的结构特征,可为燃烧、热解、气化等热化学反应提供理论基础。

     

    Abstract: Clarification of the micro molecular structure and chemical bonding characteristics of coal from the atomic or molecular scale is the theoretical basis for realizing high⁃efficient and clean transformation of all elements in coal. Among various methods,the construction and analysis of coal molecular model is an important method to thoroughly understand the microstructure and reaction of coal. At present,the studies of the inertinite in coal macerals are not paid enough attention compared with those of the vitrinite. In this study,the molecular structures of inertinite enrich⁃ ments of Qinghua coal (QH-I) and Lingwu coal (LW-I) were characterized,modeled and compared by using mod⁃ ern material characterization methods and molecular simulation technology. The chemical structure characteristics of two kinds of coal were determined,and the molecular structure models of inertinite enrichments were constructed with the QH-I C255 H179 N3 O14 S and the LW-I C244 H170 N4 O46 . The calculated and experimental spectra show that the overall fitting degree is good,indicating that the molecular structure is reasonable. The aromatic basic units in both QH-I and LW-I contain phenylnaphthalene anthracene phenanthrene. The QH-I also contains pyrene,benzo a an⁃ thracene and condensed naphthalene due to its high degree of coalification. The aliphatic structure of the two is main⁃ ly composed of aliphatic ring,oxygen⁃connected aliphatic ring and a small amount of alkyl side chain. Among them,the inertino group of Lingwu coal ( LW - I ) has a high oxygen content, resulting in a much greater number of oxy⁃ gen⁃connected aliphatic rings than the inert group of Qinghua coal (QH-I),and the molecular structure is more com⁃ plex. These findings reveal the structural characteristics of inertinite enrichment of two bituminous coals,which can provide a theoretical basis for thermochemical reactions such as combustion,pyrolysis and gasification.

     

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