Research On Peroxo-heteropolyacids(Salts) In Catalytic Oxidation Of Deep Desulfurization Of Fuel Oil

The countries make stringent environmental regulations to limit the sulfur level in gasoline and diesel with the enhancement of environmental consciousness.Currently,it is very time to do research on desulfurization technology of gasoline and diesel fuel.The demand of low-sulfur clean fuel is urgent.Conventional hydrodesulfurizaiton technology if used for this process needed severe operating conditions,such as high hydrogen pressure and reaction temperature,which were unfavorable for commercial purpose.Much interest,therefore,had been focused on oxidative desulfurization technology,which was considered one of the 'promising processes for its mild reaction condition,simple equipment design,and highly effieieney.Meanwhile,because of the simple preparation,the high catalytic activity and the environmental protection,peroxo-heteropoly compound is widely used in the area of catalysis.In ODS,H2O2 was used as oxidant and different catalysts was used to test the effect of ODS.The catalysts which was used in ODS are[C16H33(CH3)3N]3 {PO4[WO(O2)4]4}?[C16H33(CH3)3N]3 {P04[WO(02)4]4}/SiO2 and[C16H33(CH3)3N]3[PMoW3O24].This paper has investigated different influence of their preparation method on catalytic activity.Besides,the effects of reaction temperature,reaction time,catalyst contents and oxidant contents were investigated in experiment.The results show that all the three catalysts exhibit good catalytic performance for oxidative desulfurization.[C16H33(CH3)3N]3{PO4[WO(O2)4]4} was synthesized successfully by the conditions as follows:n(H3O40PW12):n(CTAB)=1:3,n(H3PW12O40):n(H2O2)=1:30,reaetion time was 10 min and the aqueous phase of pH value was natural.The effects of reaction temperature,reaction time,amount of catalyst and amount of H2O2 were investigated.The desulfurization ratio of 99.10%and 94.42%were obtained for BT and disel.Under the optimum condition of the acid catalysis of tetrathoxysilane(TEOS),loading qunatiyt of 10%,calcining temperature at 280 ? and calcining time at 6 h,which the synthesized[C16H33(CH3)3N]3 {PO4[WO(O2)4]4}/SiO2 exibit the highest catalytic performance.The desulfurization rates reached 99.75%,99.44%,86.02%and 82.17%for BT,DBT,gasoline and diesel respectively in the optimal conditions.The[C16H33(CH3)3N]3 {PO4[WO(O2)4]4}/SiO2 can be recycled 3 times without a significant decrease in activity.[C16H33(CH3)3N]3[PMoW3O24]was synthesized successfully by the conditions as follows:reaction temperature at 40 ?,reaction time at 3 h,n(H3PMo3W9O40):n(H2O2)=1:300,n(H3PMo3W9O40):n(CTAB)=1:3.By different experiment,the best reaetion conditions were found.Under the potimal conditions,high sulfur removal was obtained for BT(99.24%)and diesel(94.06%).