THE OXIDATIVE DESULFURIZATION OF FUELS WITH A TRANSITION METAL CATALYST: A COMPARATIVE ASSESSMENT OF DIFFERENT MIXING TECHNIQUES

In this study, oxidative desulfurization of sulfur compounds using hydrogen peroxide, phosphotungstic acid, and phase-transfer agent using high-intensity probe ultrasonication, and high shear mixer was investigated. The effect of agitation speed (7600--14,000 rpm), reaction temperature (50--70 degrees C), and treatment time (10--30 min) on sulfur conversion was examined and optimized using response surface methodology. A box-behnken design was employed to determine the significance of various process parameters and their interactions using analysis of variance. Analytical results for the model sulfur compounds by ultrasound-assisted oxidative desulfurization and high shear showed comparable results. Both treatment systems provided a 98% conversion of dibenzothiopene and benzothiopene to polar sulfones at 70 degrees C in 30 min. In both systems, the experimental data followed the pseudo-first-order equation with activation energy of 60 kJ degrees mol. Results indicate that ultrasound energy produce greater reaction rates when compared to mixing with no significant difference in activation energy. In addition, the advantages and drawbacks of ultrasound-assisted extraction with respect to the high shear oxidative desulfurization were discussed.