Gentle hydrotreatment of shale oil in fixed bed over Ni-Mo/Al2O3 for upgrading

Abstract

Catalyst Ni-Mo/Al2O3 was applied to gentle hydrotreatment of shale oil in a fixed bed. It shows that 84.6% of sulfur was removed from the shale oil with a yield of upgraded oil high as 96.2% under the optimal catalytic hydrodesulfurization (HDS) conditions as at a liquid hourly space velocity (LHSV) of 4 h−1, a temperature of 380 °C, a H2/oil volume ratio of 600:1, and a pressure of 4 MPa. The upgraded shale oil met the quality requirement of national standard Marine fuel oil (GB17411-2015, China) requiring sulfur contents below 0.5 wt%. With the HDS the shale oil also got obvious improvement on its heating value and viscosity. The catalyst used for upgrading was always deactivated owing to coke deposition but an in-situ high-temperature treatment in air effectively removed the coke on the surface of the catalyst to enable its high activity after a re-sulfidation operation. In order to provide low-cost hydrogen for industrial upgrading processes that implement shale oil upgrading, a conceptual process was finally proposed through coupling a high-pressure operation methanol reforming unit and the tested high-pressure HDS upgrading reactor.