Optimal design of an ionic liquid (IL)-based aromatic extractive distillation process involving energy and economic evaluation

Yang Lei*, Yuhang Zhou, Zhiqiang Wei, Yuqiu Chen*, Fen Guo, Wei Yan

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review


Extractive distillation (ED) can be used to separate mixtures with low relative volatilities that are even close to unity. It is widely adopted for the separation of aromatics and nonaromatics in the petrochemical industry. Selecting a suitable solvent is of paramount importance to ED processes. Ionic liquids (ILs) are increasingly being considered as potential options to replace organic solvents in ED processes due to their favorable properties including high boiling points and extremely low volatilities. In this work, a nonexperimental solvent screening approach, i.e., computer-aided ionic liquid design (CAILD), is employed to identify the optimal ILs. Using a novel design objective and several structural and property constraints on IL, we have identified 1,3-dimethylpyridinium tetrafluoroborate ([C1mPy][BF4]) as the best IL solvent by solving a formulated CAILD-based mixed-integer nonlinear programming problem. The separation performance of this IL is further evaluated with rigorous process simulation in Aspen Plus. Besides, process simulation of the aromatic ED process using sulfolane as the benchmark organic solvent is performed. Furthermore, a systematic analysis of the energy consumption and the process economy is conducted by investigating the optimized simulation results of the studied aromatic ED process. The [C1mPy][BF4]-based process with an assumed IL price of 50 $/kg can reduce the capital cost by 35.2%, the operating cost by 11.8%, and the total annual cost by 31.2%. The IL price at the break-even point of replacing sulfolane with [C1mPy][BF4] in the aromatic ED process is 91.03 $/kg.

Original languageEnglish
JournalIndustrial and Engineering Chemistry Research
Issue number9
Pages (from-to)3605–3616
Publication statusPublished - 2021

Bibliographical note

Funding Information:
This work was financially supported by the National Nature Science Foundation of China project (No. 21706198) and the China Scholarship Council project (Nos. 201908420380 and 201708440264).

Publisher Copyright:
© XXXX American Chemical Society

Copyright 2021 Elsevier B.V., All rights reserved.


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