Comparison of Biobutanol Production Pathways via Acetone–Butanol–Ethanol Fermentation Using a Sustainability Exergy-Based Metric
Samir Meramo, Ángel Darío González-Delgado, Lars Rehmann, Édgar Quiñones-Bolaños, Mehrab Mehrvar
Abstract
(cassava waste) is presented in this study. The modeling of process topologies involved using Aspen Plus software. Topology 1 generated a product flow rate of 316,477 t/y of butanol, while this value was 367,037 t/y for topology 2. Both processes used a feed flow of 3,131,439 t/y of biomass. This study used seven technical indicators to evaluate both alternatives, which include the return of investment, discounted payback period, global warming potential, renewability material index, inherent safety index, exergy efficiency, and exergy of waste ratio. Otherwise, this study implemented an aggregate index to assess overall sustainability performance. The results revealed that topology 2 presented higher economic normalized scores for evaluated indicators, but the most crucial difference between these designs came from the safety and exergetic indexes. Topology 1 and topology 2 obtained weighted scores equaling to 0.48 and 0.53; therefore, this study found that the second alternative gives a more sustainable design for butanol production under evaluated conditions.