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A coupled population balance model and CFD approach for the simulation of mixing issues in lab‐scale and industrial bioreactors
Author(s) -
Morchain Jérôme,
Gabelle JeanChristophe,
Cockx Arnaud
Publication year - 2014
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.14238
Subject(s) - population , computational fluid dynamics , scale (ratio) , bioreactor , mechanics , scale up , volumetric flow rate , volume (thermodynamics) , mixing (physics) , mass transfer , thermodynamics , flow (mathematics) , chemistry , biological system , physics , biology , classical mechanics , demography , organic chemistry , quantum mechanics , sociology
Lab‐scale (70 L) and industrial scale (70 m 3 ) aerated fermenters are simulated using a commercial computational fluid dynamics code. The model combines an Euler‐Euler approach for the two‐phase flow, a population balance model for biological adaptation to concentration gradients, and a kinetic model for biological reactions. Scale‐up at constant volumetric mass transfer coefficient is performed, leading to concentration gradients at the large scale. The results show that for a given concentration field and a given circulation time t c , the population (physiological) state depends on the characteristic time of biological adaptation T a . The population specific growth rate (T a ≫t c ) is found independent of the spatial location and closely related to the volume average concentration. Oppositely, the population specific uptake rate (T a ∼t c ) is spatially heterogeneous. The resulting local disequilibria between the uptake rate and the growth rate provide an explanation for the decreased performances of poorly macromixed industrial bioreactors. © 2013 American Institute of Chemical Engineers AIChE J , 60: 27–40, 2014