CFD modelling of two-phase stirred bioreaction systems by segregated solution of the Euler–Euler model

An advanced study of a bioreactor system involving a Navier–Stokes based model has been accomplished. The model allows a more realistic impeller induced flow image to be combined with the Monod bioreaction kinetics reported previously. The time-course of gluconic acid production by Aspergillus niger strain is simulated at kinetic conditions proposed in the literature. The simulation is based on (1) a stepwise solution strategy resolving first the fluid flow field, further imposing oxygen mass transfer and bioreaction with subsequent analysis of flow interactions, and (2) a segregated solution of the model replacing the multiple iterations per grid cell with single iterations. The numerical results are compared with experimental data for the bioreaction dynamics and show satisfactory agreement. The model is used for assessment of the viscosity effect upon the bioreactor performance. A 10-fold viscosity rise results in 2-fold decrease of KLa and 25% decrease of the specific gluconic acid production rate. The model allows better understanding of the mechanism of the important bioprocess

CFD stimulation of gluconic acid production in a stirred gas-liquid fermenter

Designing large-scale stirred bioreactors with performance closely matching the one achieved in lab-scale fermenters presents continuous challenge. In this contribution, dynamic modelling of the aerobic biocatalytic conversion process in viscous batch stirred tank reactor is developed. Its operation is illustrated by simulation of the interaction of fluid flow, mass transfer and reaction relevant to gluconic acid production by a strictly aerophilic Aspergiluc niger based on a “twofluid” model. As a result of this simulation, the velocity fields, the local substrate, dissolved oxygen, product and biomass concentration profiles were obtained. Constant bubble size and global gas-liquid mass transfer were assumed. The algorithm employed could be used for fast evaluation procedures regarding predictions and feedback control of aerobic bioreactor performance

Gas-Liquid Dispersion in a Fibrous Fixed Bed Biofilm Reactor at Growth and non-Growth Conditions

International audienc

Surfactant effects on aeration performance of stirred tank bioreactors

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