Integrated Vacuum Stripping and Adsorption for the Efficient Recovery of (Biobased) 2-Butanol

Abstract

Biobased 2-butanol offers high potential as biofuel, but its toxicity toward microbial hosts calls for efficient techniques to alleviate product inhibition in fermentation processes. Aiming at the selective recovery of 2-butanol, the feasibility of a process combining in situ vacuum stripping followed by vapor adsorption has been assessed using mimicked fermentation media. The experimental vacuum stripping of model solutions and corn stover hydrolysate closely aligned with mass transfer model predictions. However, the presence of lignocellulosic impurities affected 2-butanol recovery yields resulting from vapor condensation, which decreased from 96 wt % in model solutions to 40 wt % using hydrolysate. For the selective recovery of 2-butanol from a vapor mixture enriched in water and carbon dioxide, silicalite materials were the most efficient, particularly at low alcohol partial pressures. Integrating in situ vacuum stripping with vapor adsorption using HiSiv3000 proved useful to effectively concentrate 2-butanol above its azeotropic composition (>68 wt %), facilitating further product purification.