ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Comparative analysis of distillation–decantation schemes for isobutanol–water azeotropic separation: performance, energy efficiency, and VLE regression

Badra Mahida, Khadidja Benyahia, Amina Belmokhtar, Siham Berriah, and Ikram Khelifa

Department of Energy and Process Engineering, Djillali Liabes University, Sidi Bel Abbes, Algeria

E-mail: badramahida@gmail.com

Received: 15 September 2025  Accepted: 18 February 2026

Abstract:

This study evaluates, via Aspen Plus simulation, the feasibility of an advanced separation process for the high-purity recovery (99.99%) of isobutanol from its heterogeneous azeotropic mixture with water. The work combines thermodynamic modeling based on binary interaction parameters regressed from experimental vapor–liquid equilibrium data, rigorous parametric analysis, and a systematic comparison of process schemes. Two configurations were evaluated: a single distillation column followed by a decanter, and a more complex two-column, two-decanter system. The parametric study made it possible to define the optimal operating conditions, showing that a decanter temperature close to the azeotrope boiling point (≈ 362.31 K) maximizes the purity of the aqueous phase (≈ 96.6%). The results demonstrate the unequivocal superiority of the two-stage configuration. For a lean feed (20 mol% isobutanol), it achieves a recovery yield of 54%, compared to 0% for the simple scheme. Overall yields reach 77.1% and 90.3% for feeds of 50 and 70 mol% isobutanol, respectively, with concurrent improvements in water recovery (to 96.6%) and processed throughput. However, these performance gains are accompanied by a significant increase in energy demand, which peaks for feed compositions nearest the azeotropic point. This quantitative analysis establishes the two-column, two-decanter process as technically indispensable for achieving global, high-purity recovery, while clearly delineating the critical trade-off between separation efficiency and energy demand.

Keywords: Isobutanol–water separation; Distillation–decantation process; Heterogeneous azeotrope; Aspen plus simulation; Vapor–liquid equilibrium regression; Binary interaction parameters; Energy–efficiency trade-off

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04754-0

Chemical Papers 80 (6) 6129–6140 (2026)