AL-Mashhadani, M.K.H., Wilkinson, S.J. and Zimmerman, W.B. orcid.org/0000-0001-7123-737X (2015) Airlift bioreactor for biological applications with microbubble mediated transport processes. Chemical Engineering Science, 137. pp. 243-253. ISSN 0009-2509
Abstract
Airlift bioreactors can provide an attractive alternative to stirred tanks, particularly for bioprocesses with gaseous reactants or products. Frequently, however, they are susceptible to being limited by gas–liquid mass transfer and by poor mixing of the liquid phase, particularly when they are operating at high cell densities. In this work we use CFD modelling to show that microbubbles generated by fluidic oscillation can provide an effective, low energy means of achieving high interfacial area for mass transfer and improved liquid circulation for mixing.
The results show that when the diameter of the microbubbles exceeded 200 µm, the “downcomer” region, which is equivalent to about 60% of overall volume of the reactor, is free from gas bubbles. The results also demonstrate that the use of microbubbles not only increases surface area to volume ratio, but also increases mixing efficiency through increasing the liquid velocity circulation around the draft tube. In addition, the depth of downward penetration of the microbubbles into the downcomer increases with decreasing bubbles size due to a greater downward drag force compared to the buoyancy force. The simulated results indicate that the volume of dead zone increases as the height of diffuser location is increased. We therefore hypothesise that poor gas bubble distribution due to the improper location of the diffuser may have a markedly deleterious effect on the performance of the bioreactor used in this work.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
Keywords: | Microbubbles; Fluidic oscillation; Airlift bioreactor; COMSOL Mutiphysics |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Chemical and Biological Engineering (Sheffield) |
Funding Information: | Funder Grant number ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL (EPSRC) EP/J018112/1 ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL (EPSRC) EP/I019790/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 01 Nov 2016 16:16 |
Last Modified: | 18 Nov 2016 17:11 |
Published Version: | http://dx.doi.org/10.1016/j.ces.2015.06.032 |
Status: | Published |
Publisher: | Elsevier |
Refereed: | Yes |
Identification Number: | 10.1016/j.ces.2015.06.032 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:106395 |