Desulfurization of heavy oil

TLDR

Desulfurization of heavy oil is challenging because its high sulfur content, viscosity, boiling point, and refractory sulfur compounds limit the effectiveness of conventional methods. The study proposes autoxidation followed by thermal decomposition, possibly combined with biodesulfurization and hydrodesulfurization, as a promising strategy for heavy oil desulfurization. The authors reviewed literature on hydrodesulfurization, extractive, oxidative, biodesulfurization, alkylation, chlorinolysis, and supercritical water methods to assess their viability for heavy oil.

Abstract

Strategies for heavy oil desulfurization were evaluated by reviewing desulfurization literature and critically assessing the viability of the various methods for heavy oil. The desulfurization methods including variations thereon that are discussed include hydrodesulfurization, extractive desulfurization, oxidative desulfurization, biodesulfurization and desulfurization through alkylation, chlorinolysis, and by using supercritical water. Few of these methods are viable and/or efficient for the desulfurization of heavy oil. This is mainly due to the properties of the heavy oil, such as high sulfur content, high viscosity, high boiling point, and refractory nature of the sulfur compounds. The approach with the best chance of leading to a breakthrough in desulfurization of heavy oil is autoxidation followed by thermal decomposition of the oxidized heavy oil. There is also scope for synergistically employing autoxidation in combination with biodesulfurization and hydrodesulfurization.