Study On Deep Desulfurization Of High Slfur Diesel Fuels By Ultrasound

Sonochemistry is a new and rapid growing research field with broad applications in environmental engineering, green chemistry and petrochemical processing. One application of the ultrasonic cavitation degradation of organic contaminants in water is usually Advanced Oxidation Processes (AOPs).Ultrasound is successfully applied the oxidation reaction of benzothiophenes (BTs) by means of a combination of ultrasonic physical process and chemical reaction of BTs oxidation. The study results show that the ultrasound assisted oxidation (UAO) conversion of BTs is 3 to 4 times higher than normal oxidation reaction. The conversion efficient order of the UAO of BTs is 4-methyl-dibenzothiophene (4-MDBT) > dibenzothiophene (DBT) >benzothiophene (BT) . Effects of various parameters on the UAO reaction of BTs are studied to abtain the optimum reaction conditions are obtained. The oxidation conversion rate of DBT oxidized dibenzothiophene sulfone (DBTO) is as high as 90% at the optimum reaction conditions.Based on the UAO reaction study of BTs, the UAO reaction is applied to the oxidation desulfurization (ODS) reaction of high sulfur diesel fuels, in order to develop a new deep desulfurization of high sulfur diesel fuels to meet the product requirements of LSD. The research results show that sulfur removal rate of diesel fuels in ultrasound assisted oxidation desulfurization (UAODS) is significant increased to be 3 times higher than that of common ODS reaction. At the same time, effects of the various parameters on the UAODS reaction of diesel fuels are studied and the optimum reaction conditions are obtained. The sulfur content of high sulfur diesel fuel can be reduced to 50μg/g level at the optimum reaction conditions, to meet the requirements for LSD.The sulfur removal rate of diesel fuels can be greatly increased, due to the synergistic effect of metal ions (Fe2+ and Cu2+) in UAODS of diesel fuel. The study results show that the sulfur removal rates of diesel fuels are 39.1% higher in the ultrasound (Fe2+) oxidation desulfurization reaction and 30.7% in the ultrasound (Cu2+) oxidation desulfurization reaction, respectively, compared with UAODS. Therefore, the synergistic effect of Fe2+ is obviously higher compare with Cu2+ in UAODS of diesel fuel. Effects of various parameters on the ultrasound oxidation desulfurization reaction are studied and the optimum reaction conditions are obtained. The sulfur content can be reduced to 30μg/g level at the optimum reaction conditions.Kinetic studies of ultrasound oxidation of BTs, UAODS and ultrasound (metal ions) oxidation desulfurization of diesel fuels show the characteristic of first-order reaction. The apparent reaction rate constant of DBT in ultrasound assisted oxidation reaction is 5 times higher than that of common oxidation reaction. The apparent reaction rate constant of UAODS is greater than that of common ODS. The synergistic index of Fe2+ and Cu2+is 2.45 and 1.06. The apparent activation energy of DBT is 64.79 kJ/mol. The order of the apparent reaction rate constants of BTs in ultrasound assited oxidation is BT ultrasound (Cu2+) oxidation desulfurization > UAODS >common oxidation desulfurization reaction. Combining metal ions and ultrasound can also rapidly reduce the apparent activation energies of diesel fuel, the order of the apparent activation energies of UAODS is ultrasound (Fe2+) oxidation desulfurization