چكيده به لاتين
The combination of extraction methods and oxidative desulfurization due to high efficiency and good operating conditions can be considered a viable replacement for conventional desulfurization methods. In this study, the oxidation/extraction desulfurization method were investigated to remove sulfur compounds than gasoil fuel. Gasoil with a total sulfur content of 1550 ppmw was selected to studies. By evaluating various oxidation systems, hydrogen peroxide-formic acid system was used for sulfur-containing compounds oxidation in gasoil, so that after oxidation reaction, the gasoil desulfurization and recovery were obtained 96.38% and 20.64% respectively. to Choosing a polar solvent which extracted the oxidized sulfur compounds, three solvent acetonitrile, dimethylsulfoxide and Dimethylformamide were considered. Acetonitrile solvent was dismissed due to low density and close to gasoil density that causing solvent and gasoil separation was difficult. Thus, for dimethylsulfoxide and Dimethylformamide solvents, the effect of solvent to fuel ratio and number of extraction stages were investigated on desulfurization and recovery of gas oil in range of 0.5-2 and 1-3 respectively. In addition, the desulfurization by Dimethylformamide solvent was more than dimethylsulfoxide, but for gasoil recovery vice versa. Most gasoil desulfurization and recovery were obtained 97% and 96% respectively. Finally, Dimethylformamide was chosen as solvent (dispersed phase) for the removal of sulfur compounds in extraction column. Also, a single drop column were studied as extraction column. to study desulfurization and the dispersed phase behavior in single drop systems, Droplet diameter and column height were selected in the range of 1.672-4.692 and 228-550 mm, respectively. The experiments showed that the concentration of sulfur compounds in dispersed phase decreased by enhancement the droplet diameter but these concentrations increased when column height increased. Also, the overall mass transfer coefficient and overall Sherwood number increased and then decreased by increasing diameter but these numbers decreased continuously when column height increased. The overall mass transfer coefficient and overall Sherwood number also changed in the range of 0.119-0.3422(×〖10〗^(-4) m/s) and 33.07-235.66, respectively. In addition, it was observed that a single drop system had higher efficiency compared to equivalent batch systems.
Keywords: Desulfurization, single drop column, drop diameter, column height, Sherwood number
