A Non-catalytic Deep Desulphurization Process using Hydrodynamic Cavitation

Abstract

A novel approach is developed for desulphurization of fuels or organics without use of catalyst. In this process, organic and aqueous phases are mixed in a predefined manner under ambient conditions and passed through a cavitating device. Vapor cavities formed in the cavitating device are then collapsed which generate (in-situ) oxidizing species which react with the sulphur moiety resulting in the removal of sulphur from the organic phase. In this work, vortex diode was used as a cavitating device. Three organic solvents (n-octane, toluene and n-octanol) containing known amount of a model sulphur compound (thiophene) up to initial concentrations of 500 ppm were used to verify the proposed method. A very high removal of sulphur content to the extent of 100% was demonstrated. The nature of organic phase and the ratio of aqueous to organic phase were found to be the most important process parameters. The results were also verified and substantiated using commercial diesel as a solvent. The developed process has great potential for deep of various organics, in general, and for transportation fuels, in particular.

Treatment of Solvent-Contaminated Water Using Vortex-Based Cavitation: Influence of Operating Pressure Drop, Temperature, Aeration, and Reactor Scale

“…This device uses swirling flow in a novel configuration to generate cavitation. This vortex based cavitation device has shown to perform better than orifice based cavitation device for variety of applications (1,20,21). The device offered 3 to 8 times better cavitational yield (mg pollutant degraded/Joules) compared to the orifice plate.…”

Developing techno-economically sustainable methodologies for deep desulfurization using hydrodynamic cavitation

“…The other possibilities such as the formation of SO2, HSO3, H2SO4 etc. or organic species entering into the aqueous phase due to cavitation were not very relevant [27]. However, the formation of acid catalyst can certainly assist oxidative desulfurization [28,29], though, in the absence of an acid catalyst, the contribution of this mechanism may not be significant.…”

“…Different desulfurization processes have a varying degree of success in removal of these varied forms of sulfur compounds and face severe challenges in the satisfactory and efficient removal of refractory sulfur compounds. Thiophene is one of the most difficult and refractory organic sulfur compound as far as oxidative desulfurization is concerned and hence its effective removal is crucial [27][28][29].…”

“…Recently, a non-catalytic process for deep desulfurization of fuels employing hydrodynamic cavitation with vortex diode for generating vortex flow for cavitation was reported [27] with a very high sulfur removal for thiophene. It is instructive to study, the impact of the engineering designs of cavitating devices and also evaluate techno-economic sustainability.…”

“…Though the mechanism for degradation of pollutants from water using cavitation is well discussed in the literature, there have not been any reports on the two phase/multiphase systems such as the one used in the present study. A plausible mechanism for the removal of sulfur [27]includes cleavage of the sulfur bond from the attack of oxidising agent and release of sulfur dioxide, while the formation of other products such as sulfones was largely unsubstantiated. In view of insolubility of the thiophene in water and the huge difference with respect to the organic solvent, the possibility of physical transfer of the thiophene in the aqueous phase is negligible.…”