Optimization of the Oxidative Desulphurization of Residual Oil Using Hydrogen Peroxide

Abstract

The role of fuel in global economy cannot be overemphasized, it is necessary to develop new and more efficient technologies in desulphurization processes at a low cost. This research focuses on optimization of desulphurization using oxidative method for higher yields, utilizing dual acetic/formic acid catalyst on residual oil with sulphur concentration > 0.50%wt and emphasizes the improvement of physicochemical properties primarily suitable for use in fuels where regulation is becoming more stringent. The process was conducted using H₂O₂ oxidant concentration 12.5-25.0% (w/w), CH₃COOH/HCOOH acid catalyst mixture 12.5-22.0% (w/w), and reaction temperature 40-60°C. Optimization of the desulphurization parameters was done using response surface methodology based on Box-Behnken design. The optimum yield of desulphurization (60.93%) was achieved at the oxidant 18.75% (w/w), acetic/formic mixture of 17.25% (w/w), and reaction temperature of 50°C. In general, the experimentally confirmatory figures in two solutions of 63.29 ± 0.47% and 61.04 ± 0.13% match the predicted values of 62.82% and 60.91%, respectively. The total sulphur content in residual oil was reduced from 0.67 to 0.26%wt. GC-MS of the untreated sample confirm the presence of 1,2-benzisothiazole,3-(hexahydro-1H-azepin-1-yl)-1,1-dioxide, Nickel(II)bis(N,N-dihexyldithiocarbamate and Diethyl[3-[n-octadecylmercapto]-P-n-butyl-anilino methy lene] malonate with a total percentage peak area of 11.83%. In the treated sample shows no sulphur compounds. The physicochemical analysis for both treated and untreated residual oil according to ASTM were found to be within acceptable limit except sulphur content of untreated sample. After the desulphurization, treated residual oil shows a remarkable improvement in the physicochemical parameters. Hence can be applicable in industrial process and automobiles with very low sulphur emission.