MTBE Deep De-organic Sulfur Experimental Study

Methyl tert-butyl ether?MTBE?is mainly used as a gasoline additive for blending high quality gasoline in domestic,for increasing the octane.But,Sulfur compounds of MTBE will result in exceeding of the sulfur content in vehicle fuel oil.Countries around the world have promulgated strict standards to sulfur content in vehicle fuel oil and sulfur content is limited to a very low level.At present,the sulfur content in country v motor gasoline is required?10?g/g,which will put forward higher demands to desulfurization technology of MTBE now.Therefore,the desulfurization of MTBE has become a research hotspot.Extractive distillation technique is the existing desulfurization of MTBE mainly,based on this and characteristics of organic sulfides in MTBE,Study of alkaline wash-extractive distillation desulfurization and electrochemical oxidation-distillation desulfurization were explored.Experiments of Alkaline wash-extractive distillation depth desulfurization were studied,and firstly on the conditions of 28%wt NaOH alkaline solution,the amount of 0.015 alkaline solution,alkaline wash temperature 35?,and alkaline wash time 6s.Then,under the conditions of EX^-1 extraction agent,the mass ratio of EX^-1 to MTBE 1.2,extractive distillation temperature 75 ?,extractive distillation time 25min,the sulfur content of MTBE can be reduced from 132.5?g·g^-1 to 6.9?g·g^-1(<10?g·g^-1),the desulfurization rate was 94.79%.The volume of packed bed 50mL,rich solvent 20mL,under the conditions of N₂ airspeed 60h^-1,the regeneration temperature 100?,regeneration time 120min,recycling five to six times,the desulfurization rate both essentially unchanged.For further research on electrochemical oxidation-distillation desulfurization of MTBE,the following conclusions received.I The feasibility analysis on thermodynamic found that the theoretical decomposition voltage?among 0.07V to 0.57V?of sulfide electrochemical oxidation was not high,which is theoretically feasible.The order of difficulty on sulfide oxidation:mercaptans>thioethers>disulfides.II Both acidic electrolyte(DJS^-1)and basic electrolyte?DJS-2?were determined,the corresponding actual decomposition voltages were 4.8V and 3.3V.When DJS^-1 used as an electrolyte,under the conditions of the volume ratio of electric to MTBE 1.5,the decomposition voltage 4.65V,the electrolyzation temperature 30?,electrolyzation time 60min,and distillation temperature 55 ?,the MTBE raw material can be reduced from 980.6?g·g^-1 to 3.2?g·g^-1(<10?g·g^-1),the desulfurization rate was 99.67%.When DJS-2 used as an electrolyte,under the conditions of the volume ratio of electric to MTBE 1.0,the decomposition voltage 3.3V,the electrolyzation temperature 35 ?,electrolyzation time 20min,and distillation temperature 55?,the MTBE raw material can be reduced from 132.5?g·g^-1 to 2.3?g·g^-1(<10?g·g^-1),the desulfurization rate was 98.25%.?FT-IR characterization indicated that electrolyzation had no effect on the electrolysis of MTBE.IC analysis showed that the oxidation product of sulfides partially hydrolyzed to yield the sulfate ion.By GC-MS analysis combined with IC analysis speculation,in the DJS-2,the surface of the anode Cl-successively losed charge to generate Cl2,NaClO and HCIO,[O]as the oxidant agent attacked mercaptans,thioethers,and disulfides,which offered by HClO.The mercaptans oxidation may be divided into two paths,one path that mercaptans were sequentially oxidized to disulfides,sulfoxides and sulphones,then organic sulfides hydrolyzed to the sulfate ion.The other path that mercaptans were sequentially oxidized to the acid and the sulfonyl chloride,sulfonyl chloride may be sequentially hydrolyzed to sulfate ion.The thioethers first oxidized to sulfoxides and sulphones,then hydrolyzed to sulfate ion.The disulfides oxidation may be divided into two paths,one path first oxidized to two sulfoxides and sulphones,then hydrolyzed to alkylsulfonate and sulfate ion.The other oxidized to inferior sulfonyl chloride and sulfonyl chloride,and finally hydrolyzed to the sulfate ion.In the DJS^-1,the surface of the anode Me2+ first oxidized to Me3+,as the catalyst,which catalyted H2O electrolysis,providing[O]oxidant agent attacked mercaptans,thioethers and disulfides.The mercaptans first oxidized to disulfides,sulfoxides and sulphones,then organic sulfides hydrolyzed to the sulfate ion.Thioethers and disulfides were sequentially oxidized to sulfoxides,sulphones,sulphones finally hydrolyzed to sulfate ion.