Desulfurization of heavy oil

Rashad Javadli,Arno De Klerk

doi:10.1007/s13203-012-0006-6

Rashad Javadli, Arno De Klerk

Open Access

https://doi.org/10.1007/s13203-012-0006-6

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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.

Highlights

Refining of crude oil to final products requires desulfurization of the 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
Various methods were suggested for the desulfurization of oils and refinery streams

Summary

Introduction

Refining of crude oil to final products requires desulfurization of the oil. The removal of sulfur from oil is one of the central conversion requirements in most refineries and the price (and processing cost) of a crude oil is influenced by its sulfur content. The concentration and nature of the sulfur-containing compounds change over the boiling range. The amount of sulfur in a distillation fraction increases with an increase in boiling range (Table 1) (Heinrich and Kasztelaan 2001), with the heaviest fraction containing the most sulfur. The sulfur compounds become more refractory with increasing boiling point, as the dominant compound class changes from thiols, sulfides, and thiophene in the naphtha to substituted benzothiophenic compounds in the distillate (Table 2) (Weast 1988). Desulfurization of compounds that contain aliphatic sulfur, i.e. thiols and sulfides, is easier than desulfurization of compounds that contain aromatic sulfur, i.e. thiophenics

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