Desulfurization mechanism of thioether compounds in heavy oil on the (111) surface of inverse spinel Fe3O4

Abstract

The elimination of S-containing compounds in heavy oil is of significant importance to viscosity reduction and oil quality elevation in order to enhance oil recovery. In this study, the decomposition behavior of S-containing compounds in heavy oil was elucidated from a theoretical perspective in conjunction with simulative experiments. CH₃SCH₃ was employed as a model molecule on behalf of straight-chain saturated sulfides in heavy oil. The common cost-friendly inverse spinel Fe₃O₄ was selected as the catalyst. Our theoretical calculations revealed that the most feasible reaction pathway of entire CH₃SCH₃ decomposition occurred in two steps with the assistance of weakly adsorbed H₂O molecules, generating two CH₃OH molecules and one H₂S molecule, of which the first step was the rate-determining step. These calculated results were confirmed with experimental results, which contributed to a clear and reliable catalytic desulfurization mechanism for S-containing compounds in heavy oil during aquathermolysis.