| As people's environmental protection consciousness gradually strengthened,the control index of sulfur content in fuel oil is more and more strict.In fact,low sulfur or ultra-low sulfur of fuel oil will become the future development trend of countries.around the world.The conventional hydrodesulfurization process(HDS)is inefficient for removing of thiophene sulfurs and has become the bottle neck for deep desulfurization of fuel oil.HDS process must be carried out under severe operating conditions to achieve the lower sulfur content in fuel oil.HDS process is confronted with a technical and economic problem.However,the oxidative desulfurization method(ODS)due to its under mild reaction conditions can be effectively removed the HDS difficult removal of macromolecular thiophene sulfide,has broad application prospects.Three types of phosphotungstic heteropoly compound(HPC)catalysts have been prepared and the samples' constructions have been characterized by Fourier transform infrared spectroscopy(FT-IR),powder X-ray diffraction(XRD).Moreover,the oxidative desulfurization of model oil(such as benzothiophene(BT)and dibenzothiophene(DBT)),gasoline and diesel and diesel fuel catalyzed by the samples.The effects of reaction temperature and reaction time,catalyst and oxidant contents were inspected in experiment.Reaction kinetics of oxidation of model oil,gasoline and diesel were studied preliminarily.Supported phosphotungstic acid(HPW)/SiO2 catalyst was prepared through sol-gel method and the catalytic oxidative desulfurization of model oil has been investigated by HPW/SiO2.The results show that the amount of catalyst and hydrogen peroxide,reaction temperature and reaction time are impacted on the oxidative desulfurization,and the oxidative reactions of BT and DBT are in conformity with apparent-first order kinetics.The conversion rate of DBT are significantly higher than that of BT with the same reaction conditions and the sulfur content in the model oil reduce from 600 mg/L to 40.26 mg/L and 82.86 mg/L.By reaction of cetyl trimethyl ammonium bromide(CTAB)with phosphotungstic acid,the quaternary ammonium peroxotungsto phosphate catalyst was prepared.FT-IR analysis shows that the quaternary ammonium peroxotungsto phosphate keeps the Keggin structures.The catalytic oxidative desulfurization of model oil,gasoline and diesel have been investigated by the quaternary ammonium peroxotungsto phosphate catalyst.The results show that the amount of catalyst and hydrogen peroxide,reaction temperature and reaction time are impacted on the oxidative desulfurization,and the catalytic oxidative reactivity towards DBT is much higher than that of BT under the same reaction conditions.The sulfur content in the model oil of DBT and BT respectively reduce from 600 mg/L to 3.48 mg/L and 21.12 mg/L.The oxidative reactions of DBT and BT are in conformity with apparent-first order kinetics.Under the condition of the amount of catalyst 3.9%(gasoline)and 1.16%(diesel),H2O2/Oil ratio being 1:5,60 ? and 60 min,the desulfurization rates of gasoline and diesel reach 77.24%and 92.23%respectively?With tetraethylorthosilicate(TEOS)as silicon source,supported quaternary ammonium peroxotungsto phosphate/SiO2 catalyst was prepared.The catalytic oxidative desulfurization of model oil,gasoline and diesel have been investigated by quaternary ammonium peroxotungsto phosphate/SiO2.The results show that the amount of catalyst and hydrogen peroxide,reaction temperature and reaction time are impacted on the oxidative desulfurization.Under the condition of the amount of catalyst 5.66%,H2O2/Oil ratio being 1:100(BT)and 1:200(DBT),70? and 60 min,the sulfur content in the model oil reduce from 600 mg/L to 1.5 mg/L and 3.36 mg/L.Under the condition of the amount of catalyst 5.71%,H2O2/Oil ratio being 1:50,80?and 60 min,the desulfurization rate of gasoline reaches 86.02%;Under the condition of the amount of catalyst 4.53%,H2O2/Oil ratio being 1:50,80? and 60 min,the desulfurization rate of diesel reaches 82.17%. |
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