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Global and local hydrodynamics of bubble columns – Effect of gas distributor

Sharaf, Safa; Zednikova, Maria; Ruzicka, Marek C.; Azzopardi, Barry J.

Authors

Safa Sharaf

Maria Zednikova

Marek C. Ruzicka

Barry J. Azzopardi



Abstract

Global (level swell) and local (WMS – Wire Mesh Sensor) measurements were made on waters of different purities and air, in a cylindrical laboratory bubble column (2 m tall, 0.127 m dia) using two different gas distributors: a perforated plate (to produce homogeneous flow) and a spider sparger (to produce heterogeneous flow). The level swell method provided the steady space-averaged gas holdup/gas flow rate data. The WMS method provided the actual gas holdups and bubble sizes resolved in time and space at one cross-sectional horizontal plane (1 m above distributor), whose integration yields the timeaveraged data. The following results were obtained: The global and local data agree relatively well; there are distinct differences between the radial profiles and bubble size distributions between the two main flow regimes; the local information identifies why the predictions of published models, which account for the smaller and larger bubbles in the flow, may not perform well; the modelling approaches based on the hindrance and enhancement concepts prove to be suitable for the flow regime identification and description, including the transition range between the homogeneous and heterogeneous flows; based on the hydrodynamics, the specific interfacial area is obtained, together with the mass transfer coefficient.

Citation

Sharaf, S., Zednikova, M., Ruzicka, M. C., & Azzopardi, B. J. (2016). Global and local hydrodynamics of bubble columns – Effect of gas distributor. Chemical Engineering Journal, 288, 489-504. https://doi.org/10.1016/j.cej.2015.11.106

Journal Article Type Article
Acceptance Date Nov 21, 2015
Online Publication Date Dec 12, 2015
Publication Date Mar 15, 2016
Deposit Date Aug 18, 2016
Publicly Available Date
Journal Chemical Engineering Journal
Print ISSN 1385-8947
Electronic ISSN 1385-8947
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 288
Pages 489-504
DOI https://doi.org/10.1016/j.cej.2015.11.106
Keywords Bubble columns; Wire mesh sensor; Gas holdup; Bubble size; Flow regimes; Modelling
Public URL http://eprints.nottingham.ac.uk/id/eprint/35892
Publisher URL http://www.sciencedirect.com/science/article/pii/S1385894715016708
Copyright Statement Copyright information regarding this work can be found at the following address: http://eprints.nottingh.../end_user_agreement.pdf