Simulation And Experimental Study On The Separation Of Tert-butanol-isopropanol-water Mixed Solution

Tert-butanol and isopropanol as solvents in fine chemical and pharmaceutical industries are interrelated to our daily life. Unfortunately, the aqueous tert-butanol and isopropanol solution displays markedly a non-ideal behavior, forming azeotropes. Based on many literatures domestic and overseas, with ordinary distillation, to separate the aqueous tert-butanol and isopropanol solution was generalized systematically. A method of three tower distillation was proposed in the paper for the purpose of simplified production technology, environmental care, using ethylene glycol, Sulfolane, ethylene glycol as the solvents and also recovering solvent.The isobaric vapor-liquid equilibrium(VLE) behavior for the ternary mixtures of tert-butanol+isopropanol+water and the binary mixtures of tert-butanol+water,isopropanol+water and tert-butanol+isopropanol have been investigated at P=101.3KPa by means of a dynamic method using a re-circulating still. Simulation results of single -state extraction distillation in different solvents were obtained with Aspen plus simulation software. At the same time, the vapor liquid equilibrium data between the mixed solution and the solvent were determined, and the relative volatility of each component was calculated. Through the comparative analysis, the best extraction solvent of separating the mixture solution was screened out, which provided the basis for further extraction distillation simulation.Extractive distillation process was simulated by using Aspen plus software. The five references effecting of solvent ratio, reflux ratio, top product quantity, theoretical plate number and material position on extractive distillation simulation were discussed in this paper. According to the simulation results, the orthogonal experiment of five factors and four levels was designed to optimize the conditions of extractive distillation process.Simulation results showed that the purity and yield of tert-butanol were up to 99.87 % and 95.79 %, the purity and yield of isopropanol were up to 98.56 % and 9358 % under the optimized conditions. A theoretical basis for further tests was provided for this study.Confirmatory experiments by using multifunctional extractive distillation apparatus were carried out based on the results of the extractive distillation. Experimental results indicated that the purity and yield of tert-butanol were up to 96.92 % and 90.55 %, the purity and yield of isopropanol were up to 97.98 % and 90.75 % under the optimized conditions. Also, the solvents can be used circularly. The experimental results were similar to the simulation results, which verified the accurity of the simulation results.By using three-tower extractive distillation in this paper, the ternary mixtures of tert-butanol+isopropanol+water can be separated. The results of this work will be provided for the further research.