Separation Research Of1-propanol-water Azeotrope

Propanol is an important industrial raw materials?which has been widely used inthe fields of chemical industry and medicine. Dehydration is a necessary step toproduce anhydrous propanol, but propanol and water would generate minimum-boiling azeotrope,which is not easy to separated by using common distillation. In thispaper, the flowsheet of extractive distillation and azeotropic distillation, which aretwo unique distillation way, have been researched to separate the1-propanol-watermixture, and satisfactory results has been achieved.The PROII software was used to do the simulation of the distillation process toseparate1-propanol-water. In the extractive distillation process, DMSO was chosen asthe solvent, and NRTL model was used to do the calculation of liquid phase activitycoefficient. Some key parameters of extractive distillation column,such as the solventto feed molar ratio, reflux ratio, theoretical stage number, feed stage, and solvent feedstage,are also discussed and optimized to obtain the specified concentration and thelowest energy cost. The compare of separated effect of DMSO and ethylene glycolwas done. The result shows that both solvent can achieve the99.9wt%purity, but theconsumption of DMSO would be lower than ethylene glycol.In the heterogeneous azeotropic distillation process, ethyl acetate was chosen asthe entrainer to separate1-propanol-water by screen some optional entrainer. Theamount of entrainer was analysis by ternary map. The key parameters of azeotropicdistillation column and waste water recovery column, like reflux ratio, theoreticalstage number and feed stage, are optimal to get the best process flowsheet. The resultshows that the purity of propanol can be achieved as99.8wt%.To get higher purity of propanol, a new azeotropic distillation process to adoptpressure-swing distillation to rectify the entrainer by using the sensitivity of pressurechange between ethyl acetate and water, has been designed to separate1-propanol-water, as the result, the almost pure entainer can be recycle used. The key parametersof azeotropic distillation column and normal pressure recovery are optimal to get thebest process flowsheet. The result shows that both purity of propanol and recoveryethyl acetate can be achieved as99.99wt%. The batch heterogeneous azeotropic distillation experiment is done to certify theseparation effect of propanol-water mixture by using ethyl acetate as entrainer. Thevariation tendency of temperature and propanol composition in the top and bottom ofcolumn were researched. The result shows that the purity of propanol can be achievedas99.1wt%. The excellent effect by using ethyl acetate as entrainer was proved.