Separation of isobutyl alcohol and isobutyl acetate by extractive distillation and pressure-swing distillation:: Simulation and optimization

We have studied, simulated and evaluated economically two separation alternatives of a mixture made up of 52 mole% of isobutyl alcohol and 48 mole% of isobutyl acetate by means of a practical case of a plant to treat 12,000 Tm/year of the original mixture. The simulation has been carried out satisfactorily by means of a package of commercial software (Aspen HYSYS(R)) using the thermodynamic model UNIQUAC with binary parameters obtained experimentally by us. The two processes evaluated (extractive distillation using n-butyl propionate as a solvent and pressure-swing distillation) have been optimized independently from each other and the best configurations have been evaluated economically. The simulation and economic evaluation of the two separation alternatives that we have considered allow us to conclude that, for a 12,000 Tm/year plant, the pressure-swing distillation is more attractive than the extractive distillation using n-butyl propionate as an entrainer. (C) 2005 Elsevier B.V. All rights reserved.