DESULFURIZATION OF FUEL-OIL BY OXIDATION AND EXTRACTION .1. ENHANCEMENT OF EXTRACTION OIL YIELD

An oxidative-desulfurization (ODS) process was used, instead of the conventional hydrodesulfurization (HDS) process, to remove sulfur from diesel oils. This ODS process comprises two stages at ambient conditions: oxidation using nitrogen dioxide or nitric acid, followed by liquid extraction with solvents having the capability to dissolve aromatics and olefinic compounds. α-Butyrolactone is one of the best solvents. The extraction efficiency for atmospheric gas oil (AGO) was improved by preceeding the extraction with oxidation. For a given sulfur removal, the extraction results from oxidized oil showed higher extraction oil yield than the unoxidized oil. This oil yield enhancement was due to the oxidation changing the sulfur compound configurations such that they were more readily extracted by aromatic/olefinic dissolving solvents. The distribution coefficients of extraction for several sulfur compounds identified in the AGO were increased by over 100% when the oil was oxidized. © 1990, American Chemical Society. All rights reserved.