Study on diesel deep desulfurization by ultrasound assisted-H₂O₂/formic acid/phosphotungstic acid catalytic oxidation

Deep desulfurization of hydrofining diesel was treated by the process of ultrasound assisted-H₂O₂/formic acid-phosphotungstic acid catalytic oxidation. The factors affecting the treatment were studied. The experimental results showed that under the conditions of phosphotungstic acid dosage was 0.2% of the diesel mass fraction, molar ratio of O to S was 10:1, formic acid mass fraction was 80%, the volume ratio of diesel to water was 8:1, reaction temperature was 80 ℃, ultrasonic power was 240 W, the volume ratio of extractant methanol to water was 2:1, the removal rate of sulfur was 97.3% and the yield was 95.6% respectively, the total sulfur mass fraction decreased to 9.512 μg/g, which could meet the requirement of deep desulfurization of hydrofining diesel.