Oxidative extractive desulfurization of fuel catalyzed via carboxylic acid and metal halides

Abstract

Diesel is a significant transportation fuel containing sulfur compounds. Sulfur in transportation fuel emits sulfur dioxide, nitrous oxides, and particulate matter, causing air pollution. Therefore, the emission of sulfur dioxide contributes a significant role in increasing global warming. The environmental policy has been customized and modified to permit the lower limits of the sulfur compounds to eject into the atmosphere. It becomes challenging to achieve ultra-low levels of sulfur compounds through desulfurization, predominantly alkyl derivatives of dibenzothiophenes, using the conventional HDS method. The HDS process usually successfully reduces the aliphatic and alicyclic organosulfur compounds. HDS requires high temperature and hydrogen pressure, increasing its impact on refinery economics. Thus, efficiency becomes a vital point of desulfurization technologies. Therefore, refineries want another alternative desulfurization technology. Hence, another alternative method that is now gaining interest is ODS, followed by solvent extraction. The fuel was oxidized using hydrogen peroxide as an oxidant and acetic acid as a catalyst in the presence of metal halide ferric chloride. The oxidized fuel was extracted using N-methyl pyrrolidone as solvent. The presence of ferric chloride enhances extraction efficiency of organosulfur compounds from 36 % to 41 %, which further increases the concentration of ferric chloride and acetic acid may increase up to 45 % & 59.09 %, respectively. This study shows the presence of metal halides such as ferric chloride in the catalyst acetic acid makes it an excellent catalytic mixture. Hence, this catalytic mixture can be used as a catalyst in the desulfurization of fuels.