Simulation And Experiment For Separation Of Azeotropic Solvent Mixture In Pharmaceutical Industry

Tert-butyl alcohol and tetrahydrofuran are common solvent in chemical industry. They form minimum boiling azeotrope with water respectively. It produces great deal of anhydrous TBA and anhydrous THF waste liquid in pharmaceutical factory. It leads to environment polluted and great waste if the waste liquid is discharged without recycled. In order to solve the problem, this paper discussed the technology of separation of TBA—water and THF—water azeotropic mixture by special distillation. The experiment and simulation results were satisfactory.The batch distillation process of these two systems was simulated by chemical process simulation software—HYSYS. Plant 2.2. Cyclohexane was chosen as the entrainer for the system of TBA—water. NRTL model is used to predict the activity coefficients. A rigorous model for the heterogeneous azeotropic batch distillation was established. A decanter was located in the top of column. The technical parameters of the column and ratio of solvent were confirmed. The composition in distillate and reboiler, the liquid level of condenser and reboiler are researched. The TBA recovery was 63.27% while the concentration is above 99wt%. 1,2-pronanediol was chosen as the new entrainer for the system of THF—water. UNIQUAC model is used to predict the activity coefficients. A steady model of extractive distillation was established. The results showed that it leaded to a 70% reduction in solvent consumption and 43% reduction in reboiler duty than the original solvent—1,4-butanediol. Then a rigorous model for the batch extractive distillation of this system was established. The technical parameters of the column and ratio of solvent were confirmed. The composition in distillate and reboiler, the liquid level, temperature, pressure of condenser and reboiler are researched.