Fine characterization of the macromolecular structure of Shanxi low-rank coal

Due to the particular paleogeological structure of Shanxi, the macromolecular structure of Shanxi lowrank coal appears special characterizations. The combination of qualitative and quantitative methods showed that Shanxi low-rank coal was composed of amorphous carbon and ordered aromatic clusters, which was an intermediate turbostratic structure between amorphous and graphite. The molecular structure model and carbon skeleton structure model of the low-rank coal were drawn on this basis. The molecular model could simplify the molecular formula to be C 205 H 138 O 27 N 2 S, which was dominated by aromatic and aliphatic structures. The proportion of aromatic carbon in coal was 75.31%, mainly composed of 1 similar to 2 benzene rings, and the aliphatic structure was composed of cycloalkyl and alkyl side chains. The carbon skeleton structure showed that the diameter of the aromatic layer of the coal was 1.89 nm, the interlayer spacing between crystal layers was 0.36 nm, the average number of aromatic flakes per stack was 3.78, and the value of stacking height was 1.00 nm. Supplementally, parameters such as crosslinking density (0.39) and A D /A G area ratio (0.79) also provided a deeper understanding of coal structure and laid the foundation for low-rank coal utilization. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

The macromolecular structure of Shanxi low-rank coal is characterized by the special paleogeological structure of Shanxi. Qualitative and quantitative methods revealed that the coal consists of amorphous carbon and ordered aromatic clusters, forming an intermediate turbostratic structure. The molecular and carbon skeleton structure models were established, showing aromatic and aliphatic structures dominated the coal composition. The aromatic carbon content was 75.31%, mainly composed of 1 to 2 benzene rings, while the aliphatic structure consisted of cycloalkyl and alkyl side chains. The carbon skeleton structure analysis provided information on the coal's diameter, interlayer spacing, average flakes per stack, and stacking height, along with other parameters for a comprehensive understanding of the coal structure.