Comparative analysis of covalent bond cleavage and free radical behavior during the heating process in direct coal liquefaction of Naomaohu and Shangwan coals

Comparative analysis of covalent bond cleavage and free radical behavior during the heating process in direct coal liquefaction of Naomaohu and Shangwan coals

The cleavage of covalent bonds and the generation of radicals play a crucial role in product distribution during direct coal liquefaction (DCL). This paper systematically investigates the mechanisms of covalent bond cleavage and the behavior of free radical generation for Naomaohu (NMHC) and Shangwa...

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Bibliographic Details
Main Authors: Huina Xu, Xiaodong Zhou, Ning Zhen, Xuelong Yin, Ting Liu, Yakun Tang, Jingmei Liu, Lang Liu, Fengyun Ma
Format: Article
Language:English
Published: Elsevier 2025-10-01
Series:Fuel Processing Technology
Subjects:
Naomaohu coal
Direct coal liquefaction
Free radicals
Heating stage
Covalent bonds
Online Access:http://www.sciencedirect.com/science/article/pii/S0378382025000797
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Summary:The cleavage of covalent bonds and the generation of radicals play a crucial role in product distribution during direct coal liquefaction (DCL). This paper systematically investigates the mechanisms of covalent bond cleavage and the behavior of free radical generation for Naomaohu (NMHC) and Shangwan (SWC) coals during the DCL process. The concentrations of eight typical covalent bonds in raw coal and in the solid products Asphaltene (ASP) and Residue (Re) were quantified using 13C NMR, while information on free radicals was obtained through GC–MS and GC analyses. The results indicate that NMHC contains a higher concentration of easily cleavable covalent bonds, such as Cal-O and Cal-Cal, endowing it with superior reactivity compared to SWC. During the heating process, the breaking rate of Cal-Cal bonds in the ASPNMHC and ReNMHC being 3.0 times higher than those in SWC. Additionally, the proportion of aromatic radicals in OilNMHC is 19.1 % lower than that in OilSWC. This study systematically investigates the differences in reactive behavior between NMHC and SWC, emphasizing the core chemical reactions involved in DCL. It provides a theoretical foundation for developing an efficient direct liquefaction process for NMHC, oil-rich coal.
ISSN:0378-3820

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