Abstract: Residue oil hydrotreating experiments were carried out on a pilot plant unit to investigate the effect of reaction temperature and hydrotreating severity on the composition and the molecular structure of asphaltenes in the treated residue samples. Results showed that with the increase of reaction temperature or the depth of hydrogenation, the asphaltene content in the treated residue sample decreased; the sulfur, nickel and vanadium contents of asphaltene dropped, but the nitrogen content gave an increase trend. The average molecular structural parameters of asphaltene in the obtained samples were calculated from the spectrum of 1H-NMR and 13C-NMR. Results showed that with the increase of reaction temperature, the fraction of paraffins decreased and the fraction of aromatics increased; however, with the increase of hydrogenation depth, the fraction of paraffins increased and the fraction of aromatics decreased.

Key words: residue , asphaltene , 13C-NMR, 1H-NMR, molecular structure