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

摘要

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℃), 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℃ in 30 min. In both systems, the experimental data followed the pseudo-first-order equation with activation energy of 60 kJ°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.