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Hydrodynamic and mass transfer correlation in a microbubble aerated stirred tank reactor
Publikationstyp
Journal Article
Publikationsdatum
2020-10-20
Sprache
English
TORE-URI
Enthalten in
Volume
53
Issue
10
Start Page
577
End Page
584
Citation
Journal of Chemical Engineering of Japan 10 (53): 577-584 (2020-10-20)
Publisher DOI
Scopus ID
Many chemical and biocatalytic reactions are consuming gaseous species like oxygen, provided by the mass transfer across interfaces of multiphase contact apparatuses. For biocatalytic reactions a macroscopic aeration can lead to reduced enzyme activity by foaming and shear forces and for fast chemical reactions in multiphase flows, the mass transfer limitation is often the bottleneck for a process optimization. The present study investigates the use of bubbles with diameters less than 100 µm for aeration of a 3 L lab scale stirred tank reactor. For demineralized water and a solution of glucose and bovine serum albumin (BSA) as biocatalytic model protein solution, two different membrane spargers with a mean pore size of 1 µm and 2 µm are investigated. Determining the influence of the energy input on the hydrodynamics of the system, endoscopic measurements of bubble size distributions are carried out. The mass transfer performance of the two spargers is analyzed by measurements of the oxygen kla value for varying gas flow rates. As a result microbubble aeration shows a significant higher mass transfer performance compared to an open tube aeration saving 60% of the gaseous phase by reaching the same kla values. Besides high specific interfacial areas and long residance times, the Laplace pressure inside the bubble is identified as an enhancing force for mass transfer at microscale.
Schlagworte
Bubble Size Distribution
Laplace Pressure
Mass Transfer Enhancement
Microbubble Aeration
Stirred Tank Reactor
DDC Class
500: Naturwissenschaften
600: Technik
More Funding Information
The authors gratefully acknowledge the financial support provided by the Deutsche Forschungsgemeinscha (DFG) within the project (SCHL-617 and LI-899).