An experimental investigation on the oxidative desulfurization of a mineral lubricant base oil

In the present study, the oxidative desulfurization (ODS) of Sn 650 base oil with total sulfur content of 10,000 ppmw has been investigated experimentally. The response surface methodology (RSM) considering Box-Behnken design (BBD) was applied to examine the impacts of the oxidation temperature (30-70˚C), hydrogen peroxide to sulfur molar ratio (2-8), and formic acid to sulfur molar ratio (20-60) on the sulfur removal. In the next step, the appropriate values of the independent variables such as stirrer speed (750-1250 rpm), reaction time (60-180 min), and the number of extraction stages (1-4) were determined based on the optimal result obtained from the BBD. The best performance of the ODS process was found at a reaction temperature of 58˚C, an oxidant to sulfur molar ratio of 7.35, a formic acid to sulfur molar ratio of 58.5, a reaction time of 150 min, and a stirrer speed of 1250 rpm for the oxidation reaction. The achieved sulfur removal after oxidation followed by liquid-liquid extraction was 32 %, and 60 % for one extraction and three extraction stages, respectively. The changes in the base oil specifications after the ODS treatment were also investigated.

Purifying of Waste Tire Pyrolysis Oil Using an S-ZrO2/SBA-15-H2O2 Catalytic Oxidation Method

Heavy fuel oils contain a high amount of sulfur. In this work, an extent amount of sulfur content waste tire pyrolysis oil (WTPO) was used as a fuel feedstock. A promising alternative oxidative desulfurization (ODS) method was applied in sulfur removal from WTPO using a S-ZrO2/SBA-15 solid acid catalyst, hydrogen peroxide (H2O2) as an oxidant and acetonitrile as an extracting solvent at varied conditions. The prepared catalyst was characterized by X-ray diffraction (XRD), Bruanuer-Emmet-Teller (BET) method and Fourier transform infrared spectroscopy (FTIR) analysis. The influence of reaction parameters such as reaction time (30-60 min), catalyst loading (0.5–1.5 wt.%), oxidant to oil mole ratio (5–15) at fixed reaction temperature 70 °C on desulfurization of WTPO were investigated. Taguchi method was selected to design the experiment for optimizing the reaction parameters by maximizing the sulfur removal efficiency. The maximum desulfurization efficiency 59.49% was obtained under optimum conditions reaction time (60 min), catalyst loading (1.0 wt.%) and oxidant to sulfur mole ratio (10:1). A catalytic S-ZrO2/SBA-15 -H2O2 oxidation system for oxidative desulfurization of waste tire pyrolysis oil using at mild reaction conditions was developed.

Ultrasound-assisted oxidative desulfurization and denitrogenation of liquid hydrocarbon fuels: A critical review

Nowadays, a continuously worldwide concern for development of process to produce ultra-low sulfur and nitrogen fuels have been emerged. Typical hydrodesulfurization and hydrodenitrogenation technology deals with important difficulties such as high pressure and temperature operating condition, failure to treat some recalcitrant compounds and limitations to meet the stringent environmental regulations. In contrary an advanced oxidation process that is ultrasound assisted oxidative desulfurization and denitrogenation satisfies latest environmental regulations in much milder conditions with more efficiency. The present work deals with a comprehensive review on findings and development in the ultrasound assisted oxidative desulfurization and denitrogenation (UAOD) during the last decades. The role of individual parameters namely temperature, residence time, ultrasound power and frequency, pH, initial concentration and types of sulfur and nitrogen compounds on the efficiency are described. What's more another treatment properties that is role of phase transfer agent (PTA) and solvents of extraction step, reaction kinetics, mechanism of the ultrasound, fuel properties and recovery in UAOD are reviewed. Finally, the required future works to mature this technology are suggested.