Study On The Oxidative Desulfurization Technology

The oxidative desulfurization technologies were researched in this article. The effects of different factors on the desulfurization were studied and proper desulfurization conditions were found out. At the same time the oxidative desulfurization process kinetic model had a preliminary research.Ag/γ- Al₂O₃ catalysts were prepared on theγ-Al₂O₃ support by the impregnation method using AgNO₃ solution. The catalysts were characterized by N₂-adsorption specific surface area measurement(BET), X-ray diffraction(XRD), thermogravimetry-differential thermal analysis and scanning electron microscope(SEM). The effects of Ag mass fraction, impregnation time and calcination temperature on the catalytic oxidation desulfurization of catalyst were investigated using oxygen as oxidant, thiophene/thiophene as raw material. oxidation and extraction conditions on the desulfurization were determined, kinetics of the catalytic oxidation desulfurization of thiophene were studied. The result showed that: (1) the Ag/γ-Al₂O₃ catalyst with a Ag mass fraction of 18%, calcination at 500°C as well as impregnation time of 24h has superior activity. (2)the optimal conditions of oxidative desulfurization were the model oil of 20mL, O₂ oxidant of 200mL/min, Ag/γ-Al₂O₃ of 0.12g, reaction temperature of 70℃, reaction time of 50min; (3)the optimal conditions of extraction desulfurization were that using methanol as the extractor, the extraction temperature of 20℃, the extraction time of 30min, the solvent to oil ratio of 1. With these conditions, the desulfurization ratio can reached 98.1%,which was 49.0% higher than that of extraction without oxidized, the oxidized effect was remarkable; (4)kinetics of the catalytic oxidation desulfurization of thiophene meet the first order model with the Arrhenius activation energy Ea=10.52kJ/mol, A=0.044s^-1, k'_A=0.044exp[(-10.52)/RT].Na₂WO₄P_2.5/SiO₂ catalysts were prepared on the SiO₂ support by the impregnation method using Na₂WO₄ solution. The catalysts were characterized by X-ray diffraction(XRD) and scanning electron microscope(SEM). The effects of P/W molar ratio and calcination temperature on the catalytic oxidation desulfurization of catalyst were investigated using oxygen as oxidant, thiophene/thiophene as raw material. oxidation and extraction conditions on the desulfurization were determined, kinetics of the catalytic oxidation desulfurization of thiophene were studied. The result showed that: (1) the Ag/γ-Al₂O₃ catalyst with P/W molar ratio of 2.5, calcination at 600°C has superior activity. (2)the optimal conditions of oxidative desulfurization were the model oil of 20mL, O₂ oxidant of 120mL/min, Ag/γ-Al₂O₃ of 0.12g, reaction temperature of 60℃, reaction time of 40min; (3)the optimal conditions of extraction desulfurization were that using methanol as the extractor, the extraction temperature of 20℃, the extraction time of 10min, the solvent to oil ratio of 1. With these conditions, the desulfurization ratio can reached 96.6%; (4)kinetics of the catalytic oxidation desulfurization of thiophene meet the 3/2 order model with the Arrhenius activation energy Ea=25.64kJ/mol, A=424.11s^-1, k'_A=424.11exp[(-25.64)/RT].