Effect of Different Impellers and Baffles on Aerobic Stirred Tank Fermenter using Computational Fluid Dynamics

Abstract

The present research was carried out with objective to study the effect of different types of Impellers and Baffles on mixing and to examine the correlation between mixing time and mass transfer of Aerobic Stirred Tank Fermenter. An Aerobic Stirred Tank fermenter was assembled with different Impellers and Baffles alternately. The four different Impellers used were Rushton Impeller, Marine Impeller, A320 Impeller and HE3 Impeller while walled and un walled baffles were used in combination with these Impellers. The Fermenter was assembled with Resistance Temperature Detector, pH Probe and Pressure Gauge. Tachometer was used to calculate the Mixing Time of Fermenter. Volumetric Mass Transfer Coefficient was experimentally determined and calculated by the respective formulae. MATLAB was used for Mathematical Modelling of CFD, while Autodesk Simulation CFD and ANSYS FLUENT were used to generate the simulations. Turbulence lengths and Trailing Vortices were used to understand flow patterns inside the fermenter created by Impellers and Baffles. The k L a values suggested that Rushton Impeller was the most efficient among all. Turbulent Kinetic Energy and Turbulent Dissipation Rate were to understand the mixing efficiency of every Impeller.

A model‐driven approach towards rational microbial bioprocess optimization

“…These regions could become depleted of nutrients, oxygen supplies, or components accumulation that occurred due to the nonhomogenous mixing circumstances. Meanwhile, a high shear strain rate was found near to both impellers (Figure S11c), which is consistent with other reported CFD studies (Alok, 2014). In fermentations, these high shear and also high energy dissipation regions as observed in previous studies could potentially damage the cells, thereby compromising the bioproduction performances (Alok, 2014; Sarkar et al, 2016).…”

“…The advance in computing power has spurred an interest in using computational modeling approach in bioreactor studies to facilitate the rational scale‐up design and optimization to achieve the desired product yield. This could be through iterative strain engineering improvement, nutrients/substrates feed regime, bioreactor structural design, and operating control optimization (Alok, 2014; Wang et al, 2015). Integrating experiments with a modeling approach could be a valuable tool that offers a rational means in our search for improved performance of such a complex biosystem.…”

Clavulanic Acid Production by Streptomyces clavuligerus: Insights from Systems Biology, Strain Engineering, and Downstream Processing

“…Regarding the operational variables associated to fermentative processes in Streptomyces species, the nutritional effects have been more studied than the effects of hydrodynamic conditions and reactor geometry [ 75 ]. The conventional bioprocesses with Streptomyces strains are generally carried out in STRs, as this traditional geometry has been proven to be reliable as it assures good mixing, mass, and heat transfer rates [ 76 ]. Novel impeller geometries for STR have been studied as feasible alternatives for improving the oxygen dissolution and nutrient dispersion during the fermentative process [ 77 ].…”

Application of Biosorption for Removal of Heavy Metals from Wastewater

“…Liquid phase can be separated from the solid phase by a membrane system. Though the process is simple, the cost of operation is high due to high energy requirements [192].…”