Current status and future prospects of oxidative desulfurization of naphtha: a review

Desulfurization of fuels is a critical process in oil refining due to the destructive effects of sulfur compounds on human health and the environment. Naphtha is an important middle distillate product, which is utilized as an automobile, engine, and jet-B fuel or blended with other fuel fractions. Therefore, the quality of the produced naphtha is essential in terms of sulfur content. Nowadays, hydrodesulfurization (HDS) is widely used in many refineries to remove the sulfur compounds from fuels. This method needs high temperature and pressure, higher investment costs, and in-situ hydrogen sources. The oxidative desulfurization (ODS) is recommended as a suitable alternative or complementary process to HDS due to the mild reaction conditions and lack of hydrogen requirement. In recent years, the oxidative desulfurization of many real fuels such as diesel has been investigated. However, a few numbers of studies reported the oxidative desulfurization of naphtha fraction. Therefore, it is essential to address the ODS challenges for naphtha, especially in mini-refinery applications. In this study, the naphtha cuts and their compounds, the mechanism of ODS, classification and comparative analysis of different ODS methods, different types of oxidants/catalysts, and the kinetics of ODS reaction have been examined comprehensively. In addition, the effect of various parameters, such as temperature, pH, catalyst content, and oxidation time on the desulfurization efficiency is investigated. Finally, the research gaps in this field have been discussed, and suggestions for future studies in the field of oxidative desulfurization of naphtha have been proposed.