Coking of Hydroprocessing Catalyst by Residue Fractions of Bitumen

The deposition of organic material, or coke, on hydroprocessing catalyst was studied using Athabasca bitumen vacuum residue (ABVB) and narrow fractions of ABVB, prepared by supercritical fluid extraction (SCFE) with n-pentane. The feed materials were diluted in a low-sulfur gas oil and hydroprocessed over a commercial NiMo/γ-Al2O3 catalyst in a 1 L continuous-stirred tank reactor at 440 °C. The coked catalysts were Soxhlet extracted with methylene chloride; then, carbon content, surface area, pore volume, and pore size were measured. Hydrodesulfurization activity was then measured using bitumen and dibenzothiophene as reactants.The SCFE fractions that contained only saturates, aromatics, and resins gave a low yield of carbon on the catalyst (