Optimization of solvent recovery in the production of butanol by fermentation

The current energetic scenario has revived the interest in Acetone-Butanol-Ethanol (ABE) fermentations. The recovery process of ABE from the fermentation broth is particular expensive as a consequence of the low concentration established during the fermentation. Since the ABE production kinetics is characterized by product inhibition, the ABE concentration in the bioreactor is typically lower than 20g/L. The present work reports about a cost-effective flow-sheet for the recovery of butanol produced by fermentation. The study is based on approximated cost-estimation methods integrated with the simulation software Aspen Plus®. The recovery line investigated included gas-stripping, absorption of butanol in a selected liquid phase, distillation to separate the butanol from the selected liquid. The design variables were selected in agreement with the estimated degree of freedom of the process. The venture profit of the process was estimated as a function of operating conditions.