OXIDATIVE DESULFURIZATION BY CERIUM OXIDE SUPPORTED ON ALUMINA

Abstract

Sulfur compounds represent one of the most prevalent impurities found in crude oil. New technologies are required to remove the sulfilr from lower quality feed stocks to ensure that energy is available at a reasonable cost. New and more effective approaches and research is required for producing affordable ultra-low-sulfur transportation fuels, to comply with the new government sulfur regulations with maximum sulfur limit of 50 mg/1 as per Bharat IV norm. Deep desulfurization of gasoline is restricted largely by dibenzothiophene (DBT), which is the least reactive sulfur compound in gasoline. Main aims of this thesis are to synthesis and characterize cerium oxide catalyst supported on activated alumina (CeA1), and utilize it for oxidative desulphurization of DBT in simulated model oil (DBT as a source of sulfur in iso-octane). Cerium dioxide catalyst supported on activated alumina, prepared by wetness impregnation technique, was characterized by various techniques like Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive atomic X-ray (EDAX) spectra, Thermo gravimetric and Brauner- Emmett-Teller (BET) surface area. CeAl was further used as catalyst for the Oxidesulfurization (ODS) of sulfur from model oil. Results show that the oxidation activity of DBTs depends on the wt% of CeO2 loaded and calcined temperature of catalyst. The present study also reports the effect of such factors as wt % loading of CeO2 (w), contact time (t), 0/S molar ratio and temperature (T) on the conversion efficiency of DBT by CeAl. Optimum catalyst dose was found to be 10 g/1 of 10%CeA1400. The catalytic oxidation of DBT by CeAl was found to be gradual process with optimum reaction time of 3 h and 0/S molar ratio 20 at mild conditions (atmosphere pressure and 60-65 °C).