Influence of counterdiffusion effects on mass transfer coefficients in stirred tank reactors

Publikationstyp
Journal Article
Publikationsdatum
2021-09-06
Sprache
English
Author
Matthes, Simon 
Merbach, Timo Alexander 
Fitschen, Jürgen 
Hoffmann, Marko 
Schlüter, Michael 
Institut
Mehrphasenströmungen V-5 
DOI
10.15480/882.4252
TORE-URI
http://hdl.handle.net/11420/12066
Enthalten in
Chemical engineering journal advances 
Volume
8
Article Number
100180
Citation
Chemical Engineering Journal Advances 8: 100180 (2021-11-15)
Publisher DOI
10.1016/j.ceja.2021.100180
Scopus ID
2-s2.0-85126079622
Publisher
Elsevier
Accurate knowledge of volumetric oxygen mass transfer coefficients in multiphase systems is important for successfully designing and efficient operation of process plants. As a result, a large number of papers on the determination of volumetric mass transfer coefficients kLa have been published in the literature. The dynamic degassing method is probably the most common method for determining the volumetric mass transfer coefficient. However, little work is known on the influence of countercurrent diffusion effects, arising from further dissolved components, on the volumetric mass transfer coefficient. For this reason, the effect of countercurrent diffusion is investigated in the present work by using different stripping gases to determine the volumetric oxygen mass transfer coefficient. Furthermore, the effect of counterdiffusion is investigated for both conventional aeration and aeration with microbubbles. The present work shows that the choice of stripping gas has a decisive influence on the determination of the volumetric oxygen mass transfer coefficient. Moreover, it can be shown that this effect is directly proportional to the solubility of the stripping gas in the aqueous phase. Simultaneous measurements of bubble size distributions allow determining mass transfer coefficients kL. A model is developed describing the decrease in the mass transfer coefficient as a function of the solubility of the stripping gas. Furthermore, it can be shown that for the experimental determination of volumetric oxygen mass transfer coefficients, the choice of stripping gas should be adapted to secondary gas types occurring within real processes achieving a better comparability.
Schlagworte
Counterdiffusion effects
Degassing techniques
Fine bubbles
Mass transfer coefficients
Micro sparger and conventional aeration
Stirred tank reactor
DDC Class
600: Technik
Publication version
publishedVersion
Lizenz
https://creativecommons.org/licenses/by/4.0/
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