The Research On Catalytic Oxidation Of Dibenzothiophene From Oil

Oxidative desulfurization was an effective desulfurization process on petroleum refining. But some shortcoming need to be solved, such as the process of catalyst is needed for large energy consumption on the catalyst preparation process, the water-soluble oxidant could't react with sulfide completely. In this paper, the new catalyst was been preparated by impregnation method, and the oil-soluble was added in reaction system, which would resolve the shortcoming as above. Meanwhile we studied the catalyst preparation, characterization, reaction condition, repeated use, reaction kinetics and mechanism in detail. The catalyst decrease the sulfur content of model gasoline from 400 mg?kg-1 to 3.52 mg?kg-1, and can be reuse 7 times.In this paper, the catalyst W/D152 was prepared by supporting tungsten on macroporous polyacrylic cationic exchange resin D152 of weak acid series with wet-type impregnation method. The effects of the preparation conditions such as p H value, temperature and concentration of tungsten in the solution on the catalytic activity for dibenzothiophene(DBT) removal were studied, and the optimum preparation conditions were determined. The micro-morphology of the samples were observed and analyzed by scanning electron microscopy(SEM) and infrared spectroscopy(FTIR). The optimum catalytic activity in DBT conversion was observed under the conditions when the p H value was 2.5, the temperature was 30 oC and the mass volume concentration of ammonium tungstate in the solution was 2.5 wt%; The highest sulfur removal rate was 99.1% with the raw sulfur concentration of 400 mg?kg-1 and the residue sulfur concentration of approximately 3.52 mg ?kg-1, which met the EU fifth standard that limits the sulfur concentratio n to 10 mg?kg-1.The catalyst W/D152 was analyzed by the scanning electron microscopy(SEM) and Fourier Transform infrared spectroscopy(FTIR), and the data show that a thin layer of active components was covered on the catalyst surface which helps explain the satisfactory catalytic performance.Dibenzothiophene(DBT) was selected as the target compound, and oil-soluble cyclohexanone peroxide(CYHPO) as an oxidant. In order to choose the best catalytic oxidation conditions, the effect of different reaction parameters, including reaction temperature, reaction time, the weight of catalyst W/D152 and the molar ratio of CYHPO/DBT were investigated. The conversion of DBT and the sulfur content reached 99.1% and 3.52 mg?kg-1, respectively at the optimal catalytic conditions of 100 oC, mass ratio of model gasoline to catalyst W/D152 of 100, molar ratio of CYHPO/DBT of 2.5 and reaction time of 40 min.The number of the catalyst used in repeated is an important index to measure the reliability of a catalyst. During the study, the total sulfur content of treated model gasoline no long met the EU fifth standard until the catalytic was reused for more than 7 times.Reaction kinetics of this experiment was simulated, the results show that the catalytic oxidation of DBT fitted the first-order kinetic model pretty well, and the reaction rate constant was 0.1091 min-1. Contrast to without catalyst reaction kinetics, the reaction time after reaching 40 min, the desulfurization rate of only 45.3%. Furthermore, the oxidation mechanism was examined.The experiment of validation the effect on oxidative desulfurization of the new catalyst was carry on by gasoline. The experimental results show that the conversion was 97% under the same experiment reaction of model gasoline. The catalyst has a have a potential for industrial applications.