Selective poly-aromatics saturation and ring opening during hydroprocessing of light cycle oil over sulfided Ni-Mo/SiO2-Al2O3 catalyst

Abstract

Hydroprocessing of light cycle oil was carried out in a fixed bed reactor. Sulfided hydroprocessing catalyst, Ni-Mo/SiO2-Al2O3 was used, and poly-aromatic hydrocarbons in the obtained products were reduced to 5 wt%, from 64 wt% in the feed, at 380 °C and 60 bar. The GC–MS analysis confirmed that 3-ring poly-aromatic compounds converted to alkyl substituted tetralin compounds. Aromatics yield increased by nearly 4–6 times (50 wt%) in the hydroprocessed products, which could be suitable for gasoline pool due to improved octane number. Mono-aromatic hydrocarbons concentration obtained was 35–55% at all the operating conditions in the hydroprocessed products. Higher concentration of mono-aromatics leads to the improved octane number of the fuel. Properties like viscosity, cetane index, °API, and density of hydroprocessed LCO products, lead us to conclude that the obtained products are suitable for diesel as well. Under severe reaction conditions (380 °C, 70 bar), °API and cetane index values increased whereas viscosity and the density value of the products decreased. The results indicate that the catalyst shows very stable performance with time regarding meeting the required specifications for diesel.