Optimization of ultrasound-assisted oxidative desulfurization of high sulfur kerosene using response surface methodology (RSM)

An experimental investigation was conducted on the ultrasound-assisted oxidative desulfurization of non-hydrotreated kerosene. The influences of various operating parameters including oxidant-to-sulfur molar ratio (n (o)/n (s)), formic acid-to-sulfur molar ratio (n (acid)/n (s)), the ultrasound power per fuel oil volume, sonication time, and temperature on the sulfur removal of kerosene have been investigated. Response surface methodology based on Box-Behnken design has been employed. 95.46 % sulfur removal of kerosene has been achieved in the sonication time of 10.5 min under the optimal oxidation conditions (i.e., n (o)/n (s) = 15.02, n (acid)/n (s) = 107.8, and the ultrasound power per fuel oil volume of 7.6 W/mL) followed by liquid-liquid extraction. More than 90 % sulfur removal of kerosene has been achieved in about 3.5 min of sonication followed by the liquid-liquid extraction. 70.2 % sulfur removal of kerosene has been achieved in the same operating conditions after 3.5 min of oxidation followed by the liquid-liquid extraction in the absence of ultrasound irradiation. The effects of the number of extraction stages on the desulfurization and recovery of kerosene have been also investigated.