Process Simulation Study On The Separation Of Methanol And Dimethyl Carbonate By Ionic Liquids

As an important green chemical intermediate,dimethyl carbonate is widely used in batteries,coatings,pharmaceuticals and other industries.In the production of dimethyl carbonate,a methanol-dimethyl carbonate azeotrope is formed.The conventional solvent extractive distillation process has the disadvantages of large solvent loss,high energy consumption,environmental pollution,etc.The ionic liquid extractive distillation process shows good application prospects with the characteristics of small solvent loss,good reusability and environmental protection.Therefore,the research on the separation of methanol-dimethyl carbonate azeotrope by ionic liquid is of great significance.Firstly,[BMIM][NTf2]and[EMIM][NTf2]were used as extractants.The process of[BMIM][NTf2]and[EMIM][NTf2]separation of MeOH-DMC was designed in Aspen Plus.The optimal process parameters were simulated and optimized.The simulation results showed that the energy consumption was 5.42 GJ/t DMC and 6.91 GJ/t DMC respectively based on the design requirements of DMC with a purity of 99.50%and a recovery of 99.50%by using[BMIM][NTf2]and[EMIM][NTf2]as the extractants.After that,phenol(PhOH)and N,N-dimethylformamide(DMF)were used as the extractants,and the simulation optimization calculation of the traditional solvent separation MeOH-DMC azeotrope system was carried out by Aspen Plus software.The simulation results showed that:based on the design requirements of DMC with a purity of 99.50%and a recovery of 99.50%,the energy consumption was 9.14 GJ/t DMC and the loss of PhOH was 0.514(kg PhOH/t DMC)with PhOH as the extractant.When DMF was used as the extractant,the energy consumption was 8.41 GJ/t DMC,and the loss of DMF was 0.292(kg DMF/t DMC).Finally,by comparing the two types of separation processes,it was found that the specific energy consumption of the[BMIM][NTf2]separation process was saved by 35.55%and 40.70%compared with the DMF and PhOH separation processes respectively on the basis of meeting the separation requirements,and the specific energy consumption of the[EMIM][NTf2]separation process was saved by 17.84%and 24.40%compared with the DMF and PhOH separation processes respectively.The research results of this subject provided a feasible direction for the separation of MeOH-DMC azeotrope by ionic liquid.