A CFD-PBM Coupled Method to Optimize a Pilot-Scale Stirred Bioreactor

The stirred bioreactor is the core equipment in the biological fermentation industry. This work studied the influence of blade structure and operating conditions on the bioreactor performance by the population balance model (PBM) coupled computational fluid dynamic (CFD) method. The results indicate that increasing the stirring rate can improve the gas hold-up in the pilot-scale reactor but falls insignificant compared to the ventilation intensity. In addition, the Sauter mean diameter exhibits negative correlation with the unit power and is larger in the upper part of the reactor than that in the lower part. Comparative analysis with four types of blades shows that the Rushton turbine (RT) blade contributes to the better gas hold-up and dispersion performance under the same stirring rate while consuming the highest unit volume power of 2.957 W/L. Therefore, optimizing the blade structure is beneficial to improve the mixing performance and reduce the energy consumption of the bioreactor. This work examined the extent to which CFD models could be used as an efficient tool in the hydrodynamic analysis of the stirred bioreactor.