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

作者：Haijian Xu, Xiaodong Zhou, Zhen Ning, Xuelong Yin, Ting Liu, Yakun Tang, Jingmei Liu, Lang Liu, Feng‐Yun Ma · 发表于：Fuel Processing Technology · 年份：2025 · DOI：10.1016/j.fuproc.2025.108255 · 被引用次数：8 · 研究领域：Coal and Coke Industries Research、Thermochemical Biomass Conversion Processes、Coal Properties and Utilization

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 13 C 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 C al -O and C al -C al , endowing it with superior reactivity compared to SWC. During the heating process, the breaking rate of C al -C al bonds in the ASP NMHC and Re NMHC being 3.0 times higher than those in SWC. Additionally, the proportion of aromatic radicals in Oil NMHC is 19.1 % lower than that in Oil SWC . 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. • The cleavage rates of C al -C al bonds in ASP NMHC and Re SWC are each 3.0 times higher than those in SWC. • The content of aromatic radicals produced by NMHC is 55 %, which is a 19.1 % decrease compared to the 68 % found in SWC. ...