چكيده به لاتين
In recent years desulfurization of fossil fuels such as petrol and gasoline, has become increasingly important. The presence of sulfur compounds in hydrocarbon fuels leads to sulfur oxide emission into the environment and also causese deactivation of chemical catalyst. Therefore, in order to reduce the harmful effects of these pollutants, stringent laws and regulations have been established in numerous countries around the globe to reduce the amount of sulfur in petroleum products. One of the desulfurization methods recently used is oxidation desulfurization with ultrasonic waves. Due to the studies and the results of experimental tests to perform Oxidation desulfurization, the use of heterogeneous catalyst and ultrasonic waves were considered. The reason for using a solid catalyst is to solve the problem of separating and recovering the catalyst at the end of the reaction, and also the use of ultrasonic waves increases the efficiency and short reaction time. In current study, crucial parameters such as molar ratio of oxidizing agent to sulfur, molar ratio of acid to sulfur, mass of heterogeneous catalyst FeNiMo/Al2O3 to fuel volume ratio, time and temperature were evaluated by RSM method. There's a mix of Fe, Ni and Mo supported by Al2O3 , catalyst was synthesized by incipient wet impregnation method. For better understanding of the surface morphology and of heterogeneous catalyst, the scanning electron microscope (SEM) and X-ray diffraction (XRD) were performed. Based on the obtained result, in optimal condition, the molar ratio of oxidizing to sulfur and the molar ratio of acid to sulfur were 10/277 and 22/519, respectively. In the optimal experiment, the catalyst mass was 0.118 in a 25 cc fuel volume and the temperature was maintained at 50℃, the reaction time was 30 minutes under ultrasonic waves and one extraction step using DMF was perfomed after the oxidation stage. The application of these conditions resulted sulfur oxidation efficiency of more than 87%. 85 wt% formic acid as the liquid catalyst and 30 wt% oxygenated water were also used.
