Abstract

Several technologies has been developed to removal of sulfur compounds from liquid fuels is oxidative desulfurization, hydro desulfurization, catalytic hydro desulfurization, bio desulfurization etc.. Although several studies have reported enhancement effect of ultrasound irradiation on oxidative desulfurization, exact mechanism underlying this enhancement is not known yet. In this study, we have addressed this issue with dual approach with how pressure and temperature effect the desulfurization mechanism. Results of this study have given interesting revelation of interaction between mechanism of ultrasound, cavitation and oxidation system. Isolation of cavitation phenomenon helps to increase the extent of oxidation. This effect is attributed to formation of hydrogen and carbon monoxide during transient collapse of cavitation bubbles due to thermal dissociation of hexane vapor entrapped in the bubble, which hamper action of O species generated from oxidation system. Transient cavitation itself does not give rise to radical formation due to rather low temperature peaks reached during collapse. Therefore, cavitation does not enhance the oxidation process, but in fact, has adverse effect on it. Current study has established that beneficial effect of ultrasound on oxidative desulfurization system is merely of physical nature (i.e. emulsification due to intense micro-mixing) with no involvement of sonochemical effect.

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