Airlift Bioreactor for Biological Applications with Microbubble Mediated Transport Processes

Hdl Handle:
http://hdl.handle.net/10034/559335
Title:
Airlift Bioreactor for Biological Applications with Microbubble Mediated Transport Processes
Authors:
Al-Mashhadani, Mahmood K. H.; Wilkinson, Stephen J.; Zimmerman, William B.
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.
Affiliation:
University of Chester
Citation:
Al-Mashhadani, M. K. H., Wilkinson, S. J., & Zimmerman, W. B. (2015). Airlift bioreactor for biological applications with microbubble mediated transport processes. Chemical Engineering Science, 137, 243-253. doi: http://dx.doi.org/10.1016/j.ces.2015.06.032
Publisher:
Elsevier
Journal:
Chemical Engineering Science
Publication Date:
Jun-2015
URI:
http://hdl.handle.net/10034/559335
DOI:
10.1016/j.ces.2015.06.032
Additional Links:
http://linkinghub.elsevier.com/retrieve/pii/S0009250915004406
Type:
Article
Language:
en
ISSN:
00092509
Appears in Collections:
Chemical Engineering

Full metadata record

DC FieldValue Language
dc.contributor.authorAl-Mashhadani, Mahmood K. H.en
dc.contributor.authorWilkinson, Stephen J.en
dc.contributor.authorZimmerman, William B.en
dc.date.accessioned2015-07-09T11:34:01Zen
dc.date.available2015-07-09T11:34:01Zen
dc.date.issued2015-06en
dc.identifier.citationAl-Mashhadani, M. K. H., Wilkinson, S. J., & Zimmerman, W. B. (2015). Airlift bioreactor for biological applications with microbubble mediated transport processes. Chemical Engineering Science, 137, 243-253. doi: http://dx.doi.org/10.1016/j.ces.2015.06.032en
dc.identifier.issn00092509en
dc.identifier.doi10.1016/j.ces.2015.06.032en
dc.identifier.urihttp://hdl.handle.net/10034/559335en
dc.description.abstractAirlift 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.en
dc.language.isoenen
dc.publisherElsevieren
dc.relation.urlhttp://linkinghub.elsevier.com/retrieve/pii/S0009250915004406en
dc.rightsArchived with thanks to Chemical Engineering Scienceen
dc.subjectFluidic oscillationen
dc.subjectAirlift bioreactoren
dc.subjectMicrobubblesen
dc.subjectCOMSOL Mutiphysicsen
dc.titleAirlift Bioreactor for Biological Applications with Microbubble Mediated Transport Processesen
dc.typeArticleen
dc.contributor.departmentUniversity of Chesteren
dc.identifier.journalChemical Engineering Scienceen
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