Influence of Asphaltene on the Residue Hydrotreating Reaction

The influence of asphaltene contents on residue hydrotreating was studied in an autoclave. The feedstocks were Tahe deasphalted oil (DAO) mixed with different contents of asphaltene. The changes of asphaltene structure pre- and postreaction were analyzed. The results showed that the conversion of residue was improved by 11% age points when the asphaltene contents increased from 2% to 12%; the yield of gas, coke, gasoline and diesel increased to different degrees, but as the yield of vacuum gas oil (VGO) and >500 °C residue decreased, the removal rate of sulfur and nitrogen first increased and then decreased. The properties of asphaltene were changed after hydroprocessing. It was found that the molecular weight and hydrogen/carbon ratio of asphaltene decreased, the sulfur content decreased but the nitrogen content increased, and the aromaticity and the condensation degree increased. The sulfur and nitrogen contents in the hydrotreated residue increased with asphaltene content as the feedstock increased.