BACKGROUND: There are three binary azeotropes in the tetrahydrofuran/ethanol/water ternary system at atmospheric pressure. Ternary extractive distillation (ED) processes were studied to separate the ternary azeotropic mixture using two single component solvents and a mixed solvent as entrainer.RESULT: Based on the sequential iterative optimization procedure, the minimal total annual costs (TACs) of the ternary extractive distillation process using ethylene glycol (EG), dimethyl sulfoxide (DMSO), and the mixture of DMSO and EG as entrainer were obtained. Compared with two single component entrainers DMSO and EG, the TAC of the extractive distillation process with mixed entrainer (60 mol% DMSO + 40 mol% EG) decreases by 6.55% and 31.88%, respectively. Furthermore, the reboiler heat duties of two extractive distillation columns (EDCs) with mixed entrainer were compared with two single component entrainers. CONCLUSION:The results show that the optimal ED process using mixed entrainer performs better than that using single component entrainers from the perspective of economics. Moreover, there is a tradeoff between the reboiler heat duties of two EDCs, which can be adjusted by changing the entrainer performance in two EDCs. The use of mixed entrainer enhances the flexibility of the tradeoff because it only needs to change the composition of the mixed entrainer.

No abstract

No abstract

No abstract

The liquid–liquid equilibrium (LLE) of a ternary system of water (H2O) + 2-propanol + 1-decyl-3-methylimidazolium bis­(trifluoromethylsulfonyl)­imide ([Dmim]­[NTf2]) ionic liquid was measured in the temperature range from 278.15 to 298.15 K at atmospheric pressure. The distribution coefficient and selectivity were calculated to determine the influence of the temperature on the LLE. The results indicate that a decrease in temperature reduces the solubility of H2O in [Dmim]­[NTf2] and increases the immiscibility region of the ternary phase diagram. The experimental data were correlated using the nonrandom two liquid and the universal quasichemical models, and the critical properties for [Dmim]­[NTf2] were determined.