Multiobjective Stochastic Optimization Approach Applied to a Hybrid Process Production–Separation in the Production of Biobutanol

Acetone, butanol, and ethanol are produced in an acetobutylic fermentation, butanol being the main interest product because of its superior properties making it a feasible substitute for fuels coming from fossil sources. In this work we have simulated and optimized under a rigorous scheme an integrated process to produce acetone, butanol, and ethanol from lignocellulosic biomass. Since ABE fermentation presents several hurdles such as low concentration broths or inhibitory effects during fermentation, here is proposed a hybrid simultaneous system of saccharification–fermentation–separation in which inhibition products during both fermentation and enzymatic hydrolysis are limited. A liquid–liquid extraction step is selected as the recovery technique. The reactor was modeled and simulated using Matlab software coupled with Aspen Plus which simulated the separation step. The entire optimization was developed taking into consideration several objective targets such as the total annual cost and some bioindexes involved in fermentation such as productivity, yield, and butanol concentration. Our results allowed us to find a feasible operative zone where all our objective targets were not compromised when the goal was the improvement of the process to produce biobutanol.