Abstract: The thermal conversion behavior of aromatics-rich heavy oil to secondary asphalt and its hydrogenated asphalt were compared, and the influence of chemical structure on mesophase formation during thermal conversion was studied. The chemical structure and composition of the secondary asphalt and the hydrogenated secondary asphalt were analyzed by FTIR, the results were compared with those by polarized light microscopy and XRD, and the formation process of mesophase pitch in two systems was investigated. The results show that controlling the content of short alkyl side chain can effectively inhibit the occurrence of over carbonization and improve the microcosmic ordering degree of carbonized products, the short alkyl side chain can release small molecular free radicals stably, and the control of macromolecular radical significantly improves the homogeneity of the microstructure of carbonized products.

Key words: heavy oil, mesophase, chemical structure and composition, carbonization behavior