Ultrasound-assisted Desulfurization Research Articles

UV-irradiation effect on desulfurization of hydrocarbon fuels through an advanced oxidation-extraction process in presence of acid catalyst

An experimental investigation is performed for the desulfurization of model and real fuel oil samples through one-pot extraction combined with oxidation method with an acid catalyst under UV-irradiation. The kinetics of desulfurization process is obtained by fitting the data taken from a pilot-scale reactor. The effects of various operating parameters on the desulfurization efficiency and the optimal process condition were statistically analyzed using Taguchi experimental approach. The most important parameters affecting the desulfurization efficiency are temperature and the amount of acid catalyst. The obtained optimum conditions are applied to the three real fuel samples. The results of applying UV assisted and ultrasound assisted desulfurization are compared. Both methods have high desulfurization efficiencies about 90% for kerosene fuel. The desulfurization efficiency of about 75% for high sulfur diesel is obtained after a two-stage UV assisted desulfurization process. The results show that in the same conditions UV assisted process consumed ten times less energy than ultrasound assisted desulfurization.

Investigation of process variables and intensification effects of ultrasound applied in oxidative desulfurization of model diesel over MoO3/Al2O3 catalyst

A new heterogeneous sonocatalytic system consisting of a MoO3/Al2O3 catalyst and H2O2 combined with ultrasonication was studied to improve and accelerate the oxidation of model sulfur compounds of diesel, resulting in a significant enhancement in the process efficiency. The influence of ultrasound on properties, activity and stability of the catalyst was studied in detail by means of GC-FID, PSD, SEM and BET techniques. Above 98% conversion of DBT in model diesel containing 1000μg/g sulfur was obtained by new ultrasound-assisted desulfurization at H2O2/sulfur molar ratio of 3, temperature of 318K and catalyst dosage of 30g/L after 30min reaction, contrary to the 55% conversion obtained during the silent process. This improvement was considerably affected by operation parameters and catalyst properties. The effects of main process variables were investigated using response surface methodology in silent process compared to ultrasonication. Ultrasound provided a good dispersion of catalyst and oxidant by breakage of hydrogen bonding and deagglomeration of them in the oil phase. Deposition of impurities on the catalyst surface caused a quick deactivation in silent experiments resulting only 5% of DBT oxidation after 6 cycles of silent reaction by recycled catalyst. Above 95% of DBT was oxidized after 6 ultrasound-assisted cycles showing a great improvement in stability by cleaning the surface during ultrasonication. A considerable particle size reduction was also observed after 3h sonication that could provide more dispersion of catalyst in model fuel.

Ultrasound-Assisted Desulfurization of Commercial Kerosene by Adsorption

Sorption of hexyl mercaptan sulfur onto carbon-based adsorbents (activated carbon and carbon nanotubes) by ultrasonic irradiation was investigated. The adsorptive capacity was examined. Carbon nanotubes show higher adsorptive capacity. The experimental data were fitted to the Langmuir and Freundlich adsorption isotherm model.