Preparation And Characterization Of Solid Acid Catalyst On Diesel Desulfurization

Many countries’ standard on sulfur content in the diesel become strict increasingly in order to decrease pollution caused by sulfur-containing compounds,which makes low sulfur content in diesel oil a trend. The traditional hydrodesulfurization mean has no obvious effects on sulfur-containing compounds like thiophene or needs huge costs of investment,therefore,scholars start to turn to nonhydrodesulfurization.The H₂O₂/heteropoly acids system that has good effects on sulfur-containing compounds like thiophene is able to transfer sulfur-containing compounds to corresponding sulfone or sulfoxide,which makes sulfur-containing compounds’ polarity increase.Then,the oxidation product can be separated from diesel by means of extraction and adsorption.Because of these advantages, this system gets more attention from scholars.Firstly,phosphorus molybdenum vanadium heteropoly acids were synthesized by using hydrothermal method and characterized by FI-IR,XRD and EDS.The characteristic consequences showed that this catalysts have Keggin structure and vanadium element was already introduced into Keggin structure.The oxidation experiment of thiophene by using hydrogen peroxide and HPMoV2 was done,which inspects the effects of crystal number,catalyst dosage,H₂O₂ dosage,reaction temperature,reaction time on conversion rate of thiophene.The conversion rate of thiophene can achieve 86.4% when reaction conditions are that crystal number is one,the molar ratio of H₂O₂ and thiophene is 269.5,the mass ratio of catalyst and thiophene is4.4,reaction temperature is 65℃and reaction time is 120 min.Secondly,Zn was chosen as the optimal replacing mental element among these four different elements including Cr、Zr、Sb、Zn according to the result of the oxidation experiment of thiophene.Four kinds of heteropoly acid compounds catalysts were synthesized by replacing different number Mo atoms by zine atoms.The characterizations of FI-IR,XRD and EDS were done and consequences showed that zine element was already introduced into Keggin structure.The oxidation experiment of thiophene by using hydrogen peroxide and HPMoZn4 was done that contains the effects of catalyst dosage,H₂O₂ dosage,reactiontemperature,reaction time on conversion of thiophene. The conversion of thiophene can get 78.7% when reaction conditions are that the molar ratio of H₂O₂ and thiophene is 269.5,the mass ratio of catalyst and thiophene is 4.4,reaction temperature is85℃and reaction time is 60 min.At the same time,sulfur atom on the ring of thiophene form sulfuric acid root ion after oxidation by H₂O₂ and transfer to water phase from oil phase.