Oxidative Desulfurization of Hydrocarbon Feedstock Using Oxygen as Oxidizing Agent (a Review)
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ative Desulfurization of Hydrocarbon Feedstock Using Oxygen as Oxidizing Agent (a Review) E. A. Esevaa, *, A. V. Akopyana, A. V. Anisimova, and A. L. Maksimovb aFaculty
bTopchiev
of Chemistry, Moscow State University, Moscow, 119991 Russia Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow, 119991 Russia *e-mail: [email protected] Received April 27, 2020; revised May 8, 2020; accepted May 12, 2020
Abstract—The paper presents a review of scientific research in the field of oxidative desulfurization of petroleum fractions with atmospheric oxygen (as an oxidizing agent) published over the past 15–20 years. A comparative analysis of various catalytic systems in this field has been carried out. Promising areas for the development of an effective catalytic system for oxidative desulfurization processes have been identified. Keywords: oxidative desulfurization, oxygen, polyoxometalates, metal complex systems, transition metal oxides, graphene-like materials, co-oxidants DOI: 10.1134/S0965544120090091
Natural oil is a complex mixture of hydrocarbons (HCs); organic sulfur, nitrogen, and other heteroatomic compounds; and even metal compounds. During primary distillation, oil fractions contain significant amounts of organosulfur compounds, which cause equipment corrosion and poisoning of heterogeneous secondary-processing catalysts, and combustion of fuels derived from these fractions leads to emission of sulfur and nitrogen oxides into the atmosphere [1]. In this regard, desulfurization is one of the important processes for the processing of oil fractions and is aimed at obtaining products with low sulfur content for use as fuel or feedstock for petrochemical enterprises. Therefore, the permissible values of sulfur content and the standards established for them in various types of fuels in industrialized countries are strictly regulated, and there is a tendency to tighten them. At present, environmental standards for sulfur content in European countries require it to be no more than 10 ppm in gasoline or diesel fuel [2]. To implement these requirements in oil refining, a hydrotreating process is used, which is based on the removal of sulfur and nitrogen compounds at high temperature under hydrogen pressure in the presence of CoMo or NiMo catalysts [3]. As the hydrocarbon feedstock composition becomes more complex on passing from the gasoline fraction to vacuum gas oil, the process conditions become more severe: the pressure increases from 30 to 170 atm, and the temperature, from 300 to 420°C, and it is also becomes necessary to build a recycling unit for hydrogen-rich gas because of its excessive use. In the hydrotreating process, mercaptans, sulfides, and disulfides are
removed, while benzothiophene and dibenzothiophene derivatives are removed only partially, since they are the least reactive [4]. In addition, olefins and aromatic compounds are reduced to naphthenes and paraffins during hydrotreating and a large excess of hydrogen is consumed, which leads to an increase in capital and energy costs
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