Abstract: Hydrotreating reactions of Dalian mixed residue were studied in an autoclave to investigate the effect of hydrogen pressure and catalyst-to-oil mass ratio on distribution and types of basic nitrogen compounds in the liquid product. The nitrogen compounds in product and raw material were characterized by electrospray Fourier transform ion cyclotron resonance mass spectrometry (ESI FT - ICR MS). The results showed that N1 (one N atom) type alkaline compounds in the residue before and after the reaction account for most proportion, N1S1 (one N atom and one S atom) and O1 (one O atom) is next, the relative abundance of the other types are low. With increase of hydrogen pressure, most of the basic N species in product decrease. At the same time, hydrogenation breaks down the side chains of the compounds and makes the carbon number in N1 species reduce and molecular size become smaller. When catalyst-to-oil ratio increase, the relative abundance of most N compounds and molecular saturation decreases, the equivalent double bond (DBE) of N1 compounds has no significant change (DBE: 9 ~ 18) and the carbon numbers of Ni compounds decrease significantly.

Key words: residue hydrotreating, basic nitrogen compound, ESI FT-ICR MS