Papers by Keyword: Oxidative Desulfurization

Abstract: Oxidative desulfurization of dibenzothiophene (ODS-DBT) using catalyst of NiO impregnated on magnetic silica sand from Parangtritis beach (Ps) had been evaluated. The NiO-Ps catalyst was prepared using wet impregnation method with Ps to Ni (NO₃)₂·6H₂O weight ratio of 1:1. The catalyst was calcined at a temperature of 400 °C for 5 h under flow of 20 mL min^-1 of N₂ gas_. The ODS-DBT process was carried out using NiO-Ps catalyst on solution of n-hexane with a sulfur content of 500 ppm under variations of temperature, time, and H₂O₂ volume. The results of XRD and FTIR indicated the main minerals of Ps were quartz, alumina, and magnetite. The Ps and NiO-Ps had crystallinities of 59.97 and 70.32% with crystal sizes of 16.32 and 10.95 nm. The SEM-EDX and TEM analysis showed the surface of Ps was flat and NiO-Ps was rough. The BET-nitrogen absorption-desorption indicated the Ps and NiO-Ps were mesoporous materials with average pore diameters of 11.98 and 24.01 nm, total pore volumes of 0.008 and 0.057 cm³ g^-1, and specific surface areas of 2.611 and 9.502 m² g^-1. The Ps and NiO-Ps have acidity values of 1.14 and 1.74 mmol g^-1. The optimum desulfurization using NiO-Ps catalyst in the ODS-DBT was 79.40% obtained at a temperature, time, and H₂O₂ volume of 60 °C, 30 min, and 0.42 mL.

Abstract: Due to the low specifications for sulfur content in diesel, a lot of research work are been conducted to develop alternative method for desulfurization. Catalytic oxidative desulfurization (Cat-ODS) has been found to be an alternative method to replace a conventional method which is hydrodesulfurization.New catalyst formulation using tert-butyl hydroperoxide polymolybdate based catalyst system was investigated in this research utilizing tert-butyl hydroperoxide (TBHP) as oxidant and dimethylformamide (DMF) as solvent for extraction. A series of polymolybdate supported alumina catalysts were prepared using wet impregnation method, ageing at ambient room temperature for 24 hours and followed by calcination process. A commercial diesel with 440 ppmw of total sulfur was employed to evaluate the elimination of sulfur compounds. Besides, the percentage of sulfur removal was measured by gas chromatography-flame photometric detector (GC-FPD). The sulfur content in commercial diesel was successfully reduced from 440 ppmw to 35 ppmw under mild condition followed by solvent extraction. From catalytic testing, Mo-Al₂O₃ calcined at 500°C was revealed as the most potential catalyst which gave 92% of sulfur removal.

Abstract: Tungsten-containing functional mesoporousW-SiO₂ have been successfully synthesized by an one-pot and facile room-temperature procedure. These materials presented a high dispersion of tungsten species and excellent catalytic activity on the removal of sulfur compounds without any organic solvents as extractants. The catalytic performance on sulfur compounds was investigated in detail. After recycling for 8 times, the removal of the oxidation desulfurization system could still reach 92.0%.

Abstract: Heteropolyanion substituted layered double hydroxide were synthesized and used as catalysts for oxidative desulfurization in simulated fuel oil (dibenzothiophene (DBT) in n-octane) or diesel. The catalysts are recoverable and operate with high conversion efficiency under mild conditions of atmospheric pressure and 60 °C in a biphasic system using peroxide hydrogen as oxidant and acetonitrile as extractant. Zn₉Al₃(OH)₂₄PW₁₂O₄₀(ZnAlPW), Zn₉Al₃(OH)₂₄PMo₁₂O₄₀ (ZnAlPMo) and Zn₁₂Al₄(OH)₃₂SiW₁₂O₄₀(ZnAlSiW) were identified as effective catalysts for the oxidative removal of DBT from simulated fuel oil. The order of decreasing catalytic activity is ZnAlPMo > ZnAlPW > ZnAlSiW. The results show that the best catalysts, ZnAlPMo, attained to a DBT conversion of nearly 100%. All the catalysts can be readily recycled by filtration after use. The recoverable ZnAlPMo retains nearly the same catalytic activity as the fresh. ZnAlPMo was found to exhibit an ideal catalytic activity in oxidative desulfurization of diesel with a total sulfur removal rate of 91.8%.

Abstract: A polyoxometalate-based ionic liquid, 1-(4-sulfonic acid) methylimidazolium phosphotungstate ([MIMBS]₃PW₁₂O₄₀), was synthesized and characterized by Fourier transform infrared spectrum, nuclear magnetic resonance, electrospray ionization mass spectrum and thermogravimetric analyzer. [MIMBS]₃PW₁₂O₄₀ exhibited high activity for the extractive catalytic oxidative desulfurization process, together with H₂O₂ and CH₃CN/H₂O. The sulfur removal of DBT could reach 99.9% under wild conditions, and the catalyst could be used three times with only a slight decline in activity.

Abstract: Ultrasound-assisted oxidative desulfurization (UAODS) of diesel fuel in H₂O₂/Heteropoly acid/Solvent systems, was investigated. Effects of solvent, catalyst, ultrasound and reaction temperature on the oxidation desulfurization of diesel fuel were investigated. When MPA/oil was 2%wt, methanol/diesel fuel was 20%wt, ultrasound power was 400 W and ultrasound time was 10 min, the sulfur content of diesel fuel was decreased from 211 ppm to 19 ppm. The use of ultrasonic irradiation in H₂O₂/Heteropoly acid/Solvent system significantly improved the efficiency of the oxidation reaction, and solvent was helpful to make the oxidative reaction happen in the same one phase.

Abstract: Deep desulfurization of a hydrotreated diesel fuel was investigated with H₂O₂ oxidation coupled with solvent extraction intensified by ultrasound. The process parameters for the oxidation desulfurization of diesel fuel, such as the type and dosage of catalyst, co-solvent, ultrasound time, molar ratio of H₂O₂ and sulfur were investigated. The results showed that sulfur content of the hydrotreated diesel fuel was reduced from 140 ppm to 10 ppm with using 2%wt of phosphotungstic acid as catalyst, 20%wt of methanol as co-solvent during the reaction, reaction temperature at 90°C, ultrasound time for 10 min and H₂O₂/S molar ratio of 16, and ultrasound irradiation had the obvious reinforcement in oxidative desulfurization of diesel fuel.

Abstract: Deep desulfurization of a hydrotreated diesel fuel was investigated with TBHP oxidation coupled with solvent extraction intensified by ultrasound. The process parameters for the oxidation desulfurization of diesel fuel, such as the type and dosage of catalyst, co-solvent, ultrasound time, molar ratio of TBHP and sulfur were investigated. The results showed that sulfur content of the hydrotreated diesel fuel was reduced from 140 ppm to 12 ppm with using 1%wt of sodium tungstate as catalyst, 20%wt of methanol as co-solvent during the reaction, reaction temperature at 90°C, ultrasound time for 15 min and TBHP/Sulfur molar ratio of 32, and ultrasound irradiation had the obvious reinforcement in oxidative desulfurization of diesel fuel.

Abstract: The author chose three kinds of commercial resins for blank experiment and then added oxidants.We studied that how removal rate changed under different temperature and picked the D001-cc as the best supporter in desulfurization procedure. And heteropolyacid was supported onto D001-cc with different loadings,the results showed 10% was the optimal condition.

Abstract: Phosphomolybdic acid loaded on SiO₂ has been prepared as the catalyst by the sol-gel method. The catalysts were evaluated for the oxidative desulfurization of model fuel oil using hydrogen peroxide as an oxidant. Results show that the calcined temperature, Mo/Si molar ratio, catalyst dosage, H₂O₂ dosage, reaction temperature and reaction time affect the desulfurization rates. The oxidative reactions fit apparent first-order kinetics, and the apparent activation energies of BT and DBT are 51.87 KJ/mol and 25.79 KJ/mol, respectively.