Study on oxidative reaction and kinetics of simulated oil desulfurization

The oxidative desulfurization for a simulated oil(S content 1 540×10^-6) consisting of model sulfur compounds of dibenzothiophene(DBT) and toluene solvent in a H₂O₂/WO₃/ZrO₂ oxidative system was studied. The influence of oxidation temperature, reaction time, the amount of oxidant and the dosage of catalyst on the conversion of DBT were investigated. The experimental results reveal that under an optimum oxidative desulfurization condition with the temperature of 50°C, the reaction time of 90 min, the oxidant dosage of V(oil):V(H₂O₂)=20:1 and the catalyst dosage of 0.02 g/mL oil, more than 96% of DBT are oxidized to dibenzothiophene sulfone(DBTOs) that can be easily removed. Furthermore, the oxidation kinetics of dibenzothiophene was investigated. The oxidation of DBT can be treated as a first-order reaction, the apparent activation energy E_a is 55.37 kJ/mol and the pre-exponential factor A is 3.35×10⁷ min^-1.