Effect of Entrainer Thermodynamic Properties on the Separation of Ternary Mixtures Containing Two Minimum Boiling Azeotropes by Extractive Distillation

Abstract

Generally, the selection of an entrainer in extractive distillation depends on relative volatility, but our previous research shows that relying on relative volatility alone may not achieve the best economic and environmental benefits in the process. In this work, the effects of different entrainers on the separation process of ternary mixtures containing two minimum boiling azeotropes by extractive distillation were studied using a dichloromethane (DCM)/methanol (MeOH)/water system as an example. Taking the gas emission and total annual cost as objectives, the separation processes of eight entrainers in the DCM/MeOH/water system were optimized and compared by a multiobjective optimization method. The optimization results show that 1,3-propanediol had the best economic and environmental benefits, although its relative volatility was not the best. The limitations of screening entrainers by relying on relative volatility alone were demonstrated. To achieve optimal economic and environmental benefits, entrainer screening needs to consider the relative volatility, thermodynamic properties of the entrainers, and possible thermal integration schemes. This work provides a reference for the screening of entrainers and process design in extractive distillation processes.

Conceptual Design and Simulation-Based Optimization of Indirect Extractive Distillation Processes Considering Preconcentration for Separating Ternary Azeotropic Systems

“…In addition, the temperature of the recycled entrainer and the operation pressures of distillation columns are specified as fixed variables rather than optimization variables, which are specified as 323 K and atmospheric pressure, respectively. 34,35 The stage pressure drop is assumed as 0.0068 atm, and the pressure drop of the heat exchanger is assumed as 0.1 atm during the simulation processes. Moreover, the D of the PFT and IDC are calculated in advance according to feed compositions and azeotropic natures for both ICED-PRE and IIED-IDC schemes as a simplification.…”

Modeling and Optimization of a Solar-Driven System Coupled with Liquid Dehumidification and Absorption Refrigeration Based on Advanced Exergy and Exergoeconomic Analyses

“…The LDARS simulation is calculated in Aspen Plus by using the ELECNRTL method . By setting the T A2 , the specific heat provided by the STS is divided into two parts.…”

“…The LDARS simulation is calculated in Aspen Plus by using the ELECNRTL method. 35 By setting the T A2 , the specific heat provided by the STS is divided into two parts. The hightemperature part (Q H ) is used to meet the heat load of the LDS, and the remaining part (Q L ) drives the ARS.…”

Dynamic Controllability Study of Extractive and Pressure‐Swing Distillations for Tetrahydrofuran/Water Separation

“…The ED process has three components: An entrainer, which is a higher boiling solvent, is introduced. The role of the entrainer is to alter the relative volatility of the azeotrope components [14]. To preferentially recover one of the essential components in the binary fresh feed, the entrainer is fed close to the top of the first extraction column.…”