Abstract: The oleic acid modified Fe2(MoO4)3 catalyst was prepared and used in catalytic visbreaking by aquathermolysis for Karamay heavy oil. The effects of catalyst dosage, reaction temperature and reaction time on viscosity reduction were investigated. The optimum process conditions were 240 ℃, reaction time of 36 h, and 0.4% of catalyst. At the optimal conditions, the viscosity reduction rate was 61.21%. The SARA analysis indicated that 13.2% of the large hydrocarbon molecules were significantly cracked to form light components, which was the main reason for the viscosity reduction of heavy oil. The compared results of FT-IR, 1H NMR analysis of the heavy components of heavy oil before and after the reaction indicated that desulfurization, denitrogenation, ring opening, branch chain breaking and other reactions occurred in heavy components.

Key words: heavy oil, catalytic visbreaking, oleic acid modification