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

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.