Preparation And Application Of Supported V Catalysts In Oxidative Desulfurization

With the rapid development of the industrial economy,the environmental pollution caused by the burning of fossil fuels has become increasingly serious.In order to reduce the emission of sulfur oxides?SOx?from the combustion of fuel oil,governments of various countries have successively established strict sulfur standards for fuel oils.At present,the commonly used hydrodesulfurization technology requires severe operating conditions,and the effect of the removal of aromatic sulfides in the fuel is not good enough to achieve a deep desulfurization effect.Therefore,alternative efficient deep desulfurization technologies are desperately needed.Oxidative desulfurization technology has attracted wide attention due to its advantages of simple operation and high desulfurization efficiency.The key to oxidative desulfurization technology is the development of highly efficient and stable catalysts.In this paper,V/MIL-101?Cr?,V/MIL-101?Cr?-TiO₂ and V-TiO₂-SiO₂ catalysts were prepared with V₂O₅ as the active component,and characterized by SEM,XRD,BET,NH₃-TPD,FT-IR,XPS.The characterization of the catalyst was analyzed.The influence of the preparation method of the catalyst on the desulfurization performance was investigated.The reaction kinetics of the catalytic oxidative desulfurization reaction was studied.The optimum process conditions of the oxidative desulfurization reaction were determined by orthogonal test.The experimental results show that the yield of MIL-101?Cr?prepared with tetramethylammonium hydroxide as mineralizer was high.The V/MIL-101?Cr?catalyst with V₂O₅ as active component prepared by equal volume impregnation method with 20%loading content has the best desulfurization activity.The desulfurization rate can reach 98.4%under the conditions of 0.04 mL of oxidant,0.007 g of catalyst,70°C of reaction temperature,and60 min of reaction time,and no significant decrease in catalytic activity after reused under optimal conditions.The DBT oxidation product DBTO₂ was adsorbed on the V/MIL-101?Cr?catalyst surface.The V/MIL-101?Cr?catalyst has catalytic and adsorptivity.The oxidative desulfurization reaction catalyzed by V-MIL-101?Cr?was first-order reaction with apparent activation energy Ea=49.84 kJ/mol.The introduction of TiO₂ in MIL-101?Cr?-TiO₂ can increase the acidic active site and hydrothermal stability.The desulfurization rate of V/MIL-101?Cr?-TiO₂ catalyst synthesized by doping 5%of V₂O₅ can reach 99.14%.The reaction conditions are reaction temperature of80°C,reaction time of 60 min,oxidant dosage of 0.06 mL and catalyst amount of 0.01 g.No III significant decrease in activity after the catalyst was recycled for three times.The oxidative desulfurization reaction catalyzed by V/MIL-101?Cr?-TiO₂ was first-order reaction,and the apparent activation energy Ea=30 kJ/mol.Using CTAB as template and V₂O₅ as active component,V-TiO₂-SiO₂ catalyst calcined at 600°C with CTAB/Si molar ratio of 0.04 mol,Ti/Si molar ratio of 0.5 and V/Si molar ratio of 0.05 exhibited good desulfurization activity.When the reaction temperature was 70°C,the reaction time was 70 min,the amount of oxidant was 0.04 mL,and the amount of catalyst was0.01 g,the desulfurization rate can reach 98.75%.The oxidative desulfurization reaction catalyzed by V-TiO₂-Si O₂ was first order reaction.The apparent activation energy Ea=33.11kJ/mol.