Hydrocracking of petroleum vacuum residue with activated carbon and metal additives in a supercritical m-xylene solvent

Hydrocracking of vacuum residue with various types of activated carbons and metal additives was conducted at 400 °C and a hydrogen partial pressure of 3.45 MPa in supercritical m-xylene. The effects of the textural properties and surface acidity of the activated carbon on the conversion, coke formation, and distribution of oil products (naphtha, middle distillate, vacuum gas oil, and residue) were investigated. Compared to the results obtained when using bituminous coal-derived activated carbon, hydrocracking of vacuum residue with petroleum pitch-derived activated carbon resulted in a higher conversion and much higher yield of the naphtha fraction. Both activated carbons treated by acid led to an improved conversion as well as a higher naphtha fraction yield. The metal additives (Fe₂O₃, NiSO₄, and LiC ₂H₃O₂) to the VR hydrocracking with activated carbon in supercritical m-xylene contributed to the conversion as well as the yields of the light fraction (naphtha and middle distillate fractions). Moreover, with the addition 10 wt% Fe₂O₃, the yields of the conversion and light fractions were improved and coke formation on the surface of the activated carbon was reduced.