Desulfurization Of Fuel Oil By Coupled Extraction And Catalytic Oxidation

In this paper,we studied a new type of extraction/catalytic oxidation desulfurization?ECODS?system for the desulfurization of fuels,with a more economical,more stable,more secure compound potassium hydrogen sulfate salt?PMS?instead of the more commonly used hydrogen peroxide?H₂O₂?coupled with ionic liquids which contains the co-based to remove dibenzothiophene?DBT??benzothiophene?BT?and 4,6-dimethyidibenzothiphene?4,6-DMDBT?.Considering the high price of ionic liquids,we prepared the supported ionic liquid catalyst by using ionic liquid load on mesoporous silica gel?SG?or prepared an inexpensive deep eutectic solvents?DESs?substitute ionic liquids coupling with PMS for desulfurization.Specific research achievements include the following four parts:1?Functional ionic liquid[Bmim]CoCl₃ was prepared by simple mixing of cobalt chloride?CoCl₂?and 1-n-butyl-3-methylimidazolium chloride?[Bmim]Cl?.[Bmim]Co Cl₃ combined with oxidant PMS to remove the DBT in octane?simulated sulfur fuel oil?.The experimental results showed that the optimal reaction conditions were as follows:S content of 500 ppm,6 g of DBT in octane,2 g of[Bmim]CoCl₃,1 g of PMS solution,50^oC,and after the reaction 65 min,the desulfurization rate was up to97.7%.The removal of different sulfur compounds in octane after 65 min followed the trend DBT>4,6-DMDBT>BT.The ionic liquids still had high activity after 6consecutive desulfurization processes.The reaction product was analyzed by gas chromatography and mass spectrometry?GC-MS?.The final reaction product was dibenzothiophenesulfone?DBTO₂?,and the possible reaction mechanism was inferred.2?Due to the electron density of S atoms on BT was lower than that of DBT and its reactivity was relatively low,so BT was much harder to remove than DBT.BT dissolved in octane was desulfurized by ECODS.The study showed that the best degradation condition of BT in[Bmim]CoCl₃/PMS system were as follows:S content of 500 ppm,6 g of BT in octane,2 g of[Bmim]CoCl₃,1.5 g of PMS solution,50^oC,and the desulfurization rate reached 92.4%after the reaction 65 min.The results showed that the system had excellent degradation properties for thiophene compounds.3?The load catalyst[Bmim]CoCl₃/SG was prepared by sol-gel method,and the structure was characterized by IR,TGA,SEM and N₂ adsorption-desorption.[Bmim]Co Cl₃/SG and the extractant[Bmim]BF₄ and oxidant PMS were coupled to build the heterogeneous desulphurization system.Studying the effect of different reaction conditions on the desulfurization efficiency,the research results showed that DBT in octane desulfurization rate can be achieved 99.5%under the following condition:the initial sulfur content of 500 ppm,6 g of simulation oil,0.75 g of[Bmim]BF₄,0.2 g of 20 wt%PMS solution and 0.1 g of catalyst,30°C,30 min.The system greatly reduced the amount of catalyst and oxidant.4?A series of environmental friendly and more economical containing co-based deep eutectic solvent?Co-DESs?was prepared by simple mixing,and the desulfurization was studied by combining with PMS.The results showed that Co Cl₂-ChCl/2PEG also had excellent extraction and catalytic properties,when the reaction conditions were:6 g of simulated oil,0.9 g of PMS,2 g of CoCl₂-Ch Cl/2PEG,500ppm initial sulfur content?DBT?,20°C and CoCl₂-ChCl/2PEG exhibited excellent desulfurization performance under these conditions,and the desulfurization rate almost reached 100%.The desulfurization activity of different hydrogen bond donors was PEG>Pr>EG>GL.Co-DESs also showed excellent performance in recycling.There was no significant reduction in activity after 6 cycles.