Methanol-Enhanced Fe(III) Oleate-Catalyzed Aquathermolysis of Heavy Oil

Abstract

Fe(III) oleate (Fe(III)L) has been used in heavy oil aquathermolysis as catalysts, but the effect of the hydrogen donor on this reaction has not been considered. In this paper, we introduce methanol as the hydrogen donor in the Fe(III)L-catalyzed aquathermolysis to investigate the promotion effect of methanol on the aquathermolysis. The results show that the addition of methanol can increase the viscosity reduction rate of aquathermolysis from 81.81% to 91.23%. The heavy oil samples before and after aquathermolysis were characterized by thermogravimetric (TGA), differential scanning calorimetry (DSC), elemental analysis (EA), and carbon number distribution to investigate the changes in physical and chemical properties and explore the mechanism of methanol as a hydrogen promoter. There was a significant decrease in asphaltene and resin in the oil sample subjected to the reaction after the addition of methanol; the wax precipitation point decreased from 38 °C to 31 °C; the S element content decreased by 1% and the C element content increased by 4%; the content of light saturated HC (less than C10) increased and the content of saturated HC with more than C10 decreased. It shows that the addition of methanol, which provides a large amount of active hydrogen, promotes the breakage of long-chain alkanes in heavy oil, the light component content increase, promotes the breakage of C–C and C–S bonds during the reaction, making the content of heteroatoms decrease, increases the viscosity reduction rate, and improves the fluidity of oil samples. The findings of this study can help for better understanding of the mechanism of methanol in aquathermolysis and facilitate the exploration and exploitation of heavy oil.