Sequential modular simulation of ethanol production in a three-phase fluidized bed bioreactor

Abstract

A state-of-the-art sequential modular approach towards the modeling of a complex three-phase fluidized bed bioreactor has been introduced. The aim was to simulate the fermentation process of glucose for ethanol production using immobilized yeast in a gas–liquid–solid three-phase bioreactor. According to the newly-introduced dimensionless number (ASh number), a fluidized bed bioreactor was divided into several sections in which the three phases of emulsion, wake, and bubble were modeled parallel to each other. In the proposed model, two sub-models, namely, hydrodynamic and chemical reaction sub-models, were integrated to take the governing physical and chemical phenomena into account. Emulsion, wake, and bubble phases were considered as CSTR (continuous stirred-tank reactor), PFR (plug flow reactor), and bypass flow, respectively. Afterwards, mass transfer was taken into account right at the outlet of each section. The simulation results were compared with the experimental data derived from the literature in a wide range of gas velocity, liquid flow rate, biocatalyst particle size, and the concentration of glucose in the feed stream, which showed a great consistency. The simulation approach proposed in this study proved to be applicable in predicting the behavior of industrial three-phase fluidized bed reactors successfully.