Near Azeotropic Ethanol–Water Mixture Pervaporation Through a Polyvinyl Alcohol Membrane: A Parametric Study on Process Efficiency

The goal of this study was to explore how different operating parameters influence the performance of a polyvinyl alcohol (PVA) membrane in pervaporation for separating ethanol–water mixtures. Specifically, the focus was on understanding how variations in feed composition, temperature, and permeate pressure affect the separation efficiency. The study aimed to provide a range of operating conditions that offer a balance between maximizing both the purity and quantity of ethanol. This was achieved through statistical models, which were generated by simulating the pervaporation process under various conditions using COMSOL Multiphysics^® 6.3 and following a Box–Behnken design. It was found that similar operating conditions (temperature ~100 °C; pressure ~4–5 kPa) are suitable for both kinds of mixtures near azeotrope, with higher water content (~0.15 mass fraction) and lower water content (~0.05 mass fraction) obtaining very high recuperation degrees (generally above 99%). For more concentrated solutions (lower water content), it was possible to obtain optimal trade-off solutions (separation degree vs. retentate enrichment in ethanol), even at lower temperatures (~80 °C).