Unlocking the Benefits of Hybrid and Standalone Pervaporation for Sustainable Isopropanol Dehydration with HybSi® AR Membranes

Abstract

This study presents the first combined techno-economic and environmental analysis of IPA dehydration using HybSi (R) membranes across three configurations, offering a low-emission alternative to conventional azeotropic distillation. The processes are simulated in Aspen Plus, and include two hybrid separation processes (i.e., distillation-pervaporation and distillation-pervaporation-distillation) and one standalone pervaporation process. The pervaporation module uses data from experiments that were performed using HybSi (R) AR membranes at 130 degrees C and two vacuum pressures (20 and 50 mbar). The separation processes were systematically compared using a comprehensive set of performance indicators covering technical, economic, and environmental aspects. A new cost-efficiency metric, COPCO, is introduced, alongside updated modeling under 2024 market conditions. The isopropanol recovery and water selectivity were >99.5% and >98.7%, respectively, in all pervaporation-based processes. It was found that the hybrid distillation-pervaporation process resulted in a 42% reduction in the levelized cost of the benchmark azeotropic distillation process, while standalone pervaporation resulted in a 38% reduction. The CO2 footprint was also reduced significantly in all cases, up to 86% in the case of standalone pervaporation compared to azeotropic distillation. The COPCO analysis revealed that the distillation-pervaporation configuration offers the highest cost-efficiency among the evaluated systems. Sensitivity analysis revealed that feed flow rate, average water flux, membrane module price, membrane lifetime, and steam price significantly impact the levelized cost. Lower vacuum pressure and feed water near the azeotropic composition enhance economic performance.