Oxidative Desulfurization of Fuel Oils

Several attractive approaches toward oxidative desulfurization of fuel oils, such as using H(2)O(2)/organic acids, H(2)O(2)/heteropolyacid, H(2)O(2)/Ti-containing zeolites, and other non-hydrogen peroxide systems (e.g., t-butyl hydroperoxide etc.) are reviewed. A new alternative oxidative desulfurization process using emulsion catalysts was developed mainly by our group, is introduced in detail. Limitations because of interphase mass transfer are greatly reduced in the emulsion reaction medium. The amphiphilic emulsion catalysts can selectively oxidize the sulfur-containing molecules present in diesel to their corresponding sulfones when using H(2)O(2) as the oxidant under mild conditions. Tie sulfones in the oxidized fuel oils can be removed by a polar extractant. The sulfur level of a prehydrotreated diesel can be lowered from a few hundred mu g/g to 0.1 mu g/g after oxidation and subsequent extraction whereas the sulfur level of a straight-run diesel can be decreased from 6000 to 30 mu g/g after oxidation and extraction.