Abstract: Two kinds of residue with different nitrogen content were taken as the research object, and the fluidized bed hydroconversion experiments were carried out under the same process conditions, and the properties and structure of feedstock oils and their hydrotreated oils were analyzed; the characteristics of two kinds of residue hydroconversion in fluidized bed were investigated, and their molecular structures were explained. The results showed that the average molecular structure of residue with higher nitrogen content had higher condensation degree, more aromatic rings and more naphthenic rings than that of the residue with lower nitrogen content. With the increase of the reaction temperature, the sulfur bridge bond of the archipelagic molecules of the higher nitrogen residue broke, the molecular diffusion resistance decreased, which made it easier to approach the catalyst active center for conversion. At the same time, the residue with higher nitrogen content was more likely to undergo naphthenic dehydrogenation and aromatic condensation reactions, resulting in coking precursors, this was just the reason why it was necessary to strictly control the conversion depth in the fluidized bed process for treating residue with high-nitrogen content.

Key words: resid, fluidized bed, hydroconvertion, nitrogen content, nuclear magnetic resonance, molecular structure