Dynamic Modeling of a Fermentation Process with Ex situ Butanol Recovery (ESBR) for Continuous Biobutanol Production

Abstract

A dynamic model for a fermentation process equipped with an ex situ butanol recovery (termed “ESBR” hereafter) system is proposed for continuous production of biobutanol. Since the proposed ESBR system integrates a fermenter with a stirred-tank-type adsorption column, the dynamic model includes kinetic models for both the fermentation (the Monod/Luedeking-Piret model) and the adsorption (the extended Langmuir model). Parameters in the kinetic models are initially determined using data from batch and fed-batch fermentation experiments with in situ butanol recovery (ISBR). The initially developed model is then used to find a feasible operating condition for an experimental ESBR system, and its parameter values are further tuned using experimental data from the proposed ESBR system for accurate predictions in the butanol and glucose concentration range seen in the ESBR operation. The approach to improving the model accuracy consists of two steps: (1) identifying the critical parameters by performing a sensitivity analysis and (2) re-estimating the selected parameters using data obtained during cyclic operation of the proposed ESBR system. Accordingly, the developed model based on the kinetics for both fermentation and adsorption can describe and predict the behavior of the proposed ESBR system. Thus, the proposed systematic approach provides a reliable platform for the optimal scale-up design and control studies of the ESBR system.