Diesel Oil Upgradation by Ultrasound Irradiation: A Study on the Effects of Main Operational Parameters

The main objective of this work is to upgrade a diesel oil sample from Shiraz Oil Refining Co. (SORC) to reduce the sulfur content, as well as break the kinematic viscosity of the feedstock. Effects of several operating parameters including volume of hydrogen peroxide/acetic acid as an oxidant mixture, amounts of tetraoctylammonium bromide as a phase transfer agent (PTA) and phosphotungstic acid as a transition metal catalyst (TMC) and time were first screened using two-level factorial design and then optimized with the Box-Behnken scheme. It was shown that the kinematic viscosity cannot be substantially reduced due to the low power generated by the ultrasonicator. In addition, irradiation time has the least effect on desulfurization efficiency of the oil among the parameters studied in this work. Moreover, results showed that at optimal conditions of 13.17 ml hydrogen peroxide, 17.26 ml acetic acid, 0.15 g PTA and 1.5 g cataly