Concentrating Isopropanol Using a Pervaporation Pilot-Scale System and Simulating Membrane Performance in a Single-Stage Process

As a fuel, bioalcohol could be an alternative to diesel. In this study, a membrane separation process for concentrating isopropanol from fermented fluids was investigated with a focus on recovery from regions with a low concentration of isopropanol. A pervaporation membrane composed of PDMS and ZSM-5 was assembled as a spiral-type element that produced an isopropanol/water separation factor of 11.5 and a permeate flux of 0.025 kg/m2/h. Subsequently, a two-stage membrane separation process was demonstrated, and it showed that isopropanol could be recovered at a concentration of 50.7 wt % for a recovery of 8%. Furthermore, membrane recovery performance could be simulated in a single-stage process. To attain a 50 wt % concentration of isopropanol and achieve 99% recovery, it is necessary for the isopropanol/water separation factor to reach a value of 72 or higher.