Catalytic Gasoline Extraction-electrochemical Oxidation Coupled Desulfurization Experiment Research

In our country,fluid catalytic cracking(FCC)gasoline ratio is more than 80%in commercial gasoline,contributes 90%sulfides for commercial gasoline.At now,the technology of desulfurization could decrease the sulfides contention in oil.But the condition,operation and recycle of catalyzer was difficulty.Thus,it is very important to develop a mild,simple and recyclable desulfurization method.The main technology of this dissertation is combined the extraction and electrochemical oxidation to remove the sulfides in catalytic gasoline.On the basis of group previous research,the NaCl solution as electrolyte combined with different polar solution to discuss the desulfurization efficiency and yield.The experimental results showed that the SW-3 and NaCl coupled system was better than other.Then the influence factors of gasoline desulfurization process by combing of extraction-electrochemical oxidation desulfurization were investigated.Under the volume ratio of NaCl solvent and SW-3 was 2:1,the volume ratio of electrolyte and raw oil was 2:1,the concentration of NaCl solvent was 20 wt.%,electric current was 400mA/cm2,electrolysis temperature was 25? and reaction time was 50min,the concentration of sulfides could decrease from 38.4?g/g to 1.2?g/g,the desulfurization efficient and yield was 96.87%and 96.52%,respectively.And sulfides content meets the standard of "International standard V”.Under the optimum desulfurization experiment conditions,the other work as follows:(1)Under the Cl-of electrolyte was a fixed value,the desulphurization experiment was carried out for the reuse of electrolyte.The desulfurization efficient was still 97%,after the electrolyte reused 6 times.It is indicated that the electrolyte had a good reusability.(2)The desulphurization performance of FCC gasoline,distilled gasoline,kerosene and diesel oil has been discussed.The desulfurization rate of gasoline and kerosene could reach more than 80%.The desulfurization efficient of diesel oil is above 65%.Thus,this system has good adaptability.In this article,the kinetics of combing of extraction-electrochemical oxidation desulfurization(one step)and electrochemical oxidation-extraction desulfurization(two steps)was researched.Through the experiment,both of them were satisfied pseudo-first-order kinetics.The activation energy of electrochemical oxidation and extraction(20.591kJ/mol)is bigger than combing of extraction-electrochemical oxidation(13.353kJ/mol).It was indicated that combing of extraction-electrochemical oxidation desulfurization was a better technology.Then the model oils were also discussed the kinetics.The order of different sulfides:N-butyl mercaptan>Diethyl disulfides>Benzothiophene>2-Methylthiophene>Thiophene.According the analysis results of the electrolyte and model oil before and after desulfurization,the reaction mechanism was obtained.The Cl ion was electrolyzed to Cl2 at anode.Then Cl2 could be transformed to ClO-when dissolved in water.It can be decomposed into[O]with oxidation activity.The pathway of[O]oxidized sulfides as follows:(1)the organic sulfides entered electrolyte by polar solvent,oxidized to sulfoxide,sulfone and sulfonic acid.(2)a part of sulfides was oxidized in oil and then removed by polar solvent in electrolyte.