关键词: 固定床渣油加氢, Flory-Huggins模型, 沥青质稳定性, 参数

Abstract: The effects of polycyclic aromatic hydrocarbons on the removal of impurities and the inhibition of carbon accumulation on catalyst in the RICP technology were studied with an autoclave using Saudi Arab (light) atmospheric residue as raw material. A method based on Flory-Huggins activity coefficient model was established to investigate the stability of asphaltenes at 380 ℃ and 14.0 MPa. The parameter A/B ratio was calculated, where A represents the reactivity of active hydrogen for HDS, HDN, HDCCR, and B is the reactivity of active hydrogen for asphaltene hydrogenation. It shows the tendency of reactive hydrogen to focus on the reaction: larger A means the higher the efficiency of active hydrogen in removing impurities; while the smaller B is the more efficient active hydrogen in the hydrogenation of asphaltenes. The results showed that after hydrotreating, the solubility difference between asphaltene and residual oil (containing dissolved hydrogen) increased, and the stability of asphaltene became worse. When the catalysts RDM-32, RDM-53 and RCS-31 were graded at a ratio of 40:10:50, the value of A/B for Saudi Arab (light) residue reached the maximum at 380 ℃ and 14.0 MPa. It indicated that the introduction of high aromatic fraction is beneficial to further increase the value of A/B. The reason why PAHs improve the impurity removal and inhibit catalyst carbon accumulation is that PAHs optimize the efficiency of active hydrogen for impurity removal and asphaltene hydrogenation.

Key words: fixed bed residue hydritreating, Flory-Huggins model, asphaltene stability., parameter