Anaerobic Bio-reactor Modeling

Abstract EcoLodge aims at providing a proof-of-concept for a new, integrated biotechnological production process for C8 ester butyl butyrate, a promising supplement/substitute for diesel and jet engine fuels, from lignocellulose derived C5 and C6 sugars. Butanol and butyric acid are the process intermediates produced via anaerobic fermentation. This paper focuses on mathematical model simulation for BuOH fermentation and integrated gas stripping unit. Inhibitory effects of butanol and substrate are identified as main obstacles for high productivity butanol fermentation. Therefore, in situ removal of inhibitory butanol from the bio-reactor by gas stripping is suggested taking the substrate inhibition into consideration. Mathematical models from the literature are employed together with experimentally estimated model parameters. Model simulations of the integrated unit are performed in continuous mode for determination of optimum values for substrate concentration in feed and feed flow rate. The full domain of the operating ranges were explored for three different inhibitory concentrations of butanol (5,8 and 10 g/l), which resulted in performing 14000 + simulation experiments. The results provide a clear insight into the feasible combinations of the operating conditions. The optimal operating range for 5 g/l is obtained in this study will be employed in experimental bio-reactor and gas stripping unit in the next phase of the project.