Open AccessMonitoring gradient formation in a jet aerated bioreactor
Author(s) -
Weber Sebastian,
Schaepe Sebastian,
Freyer Stephan,
Kopf MichaelHelmut,
Dietzsch Christian
Publication year - 2019
Publication title -
engineering in life sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.547
H-Index - 57
eISSN - 1618-2863
pISSN - 1618-0240
DOI - 10.1002/elsc.201800122
Subject(s) - aeration , mass transfer , mixing (physics) , bioreactor , jet (fluid) , homogenization (climate) , continuous stirred tank reactor , micromixing , oxygen , chemical engineering , materials science , analytical chemistry (journal) , chemistry , mechanics , chromatography , physics , biology , organic chemistry , biodiversity , ecology , quantum mechanics , engineering
Jet aerated loop reactors (JLRs) provide high mass transfer coefficients (k L a) and can be used for the intensification of mass transfer limited reactions. The jet loop reactor achieves higher k L a values than a stirred tank reactor (STR). The improvement relies on significantly higher local power inputs (∼10 4 ) than those obtainable with the STR. Operation at high local turnover rates requires efficient macromixing, otherwise reactor inhomogeneities might occur. If sufficient homogenization is not achieved, the selectivity of the reaction and the respective yields are decreased. Therefore, the balance between mixing and mass transfer in jet loop reactors is a critical design aspect. Monitoring the dissolved oxygen levels during the turnover of a steady sodium sulfite feed implied the abundance of gradients in the JLR. Prolonged mixing times at identical power input and aeration rates (∼100%) were identified for the JLR in comparison to the STR. The insertion of a draft tube to the JLR led to a more homogenous dissolved oxygen distribution, but unfortunately a reduction of mixing time was not achieved. In case of increased medium viscosities as they may arise in high cell density cultivations, no gradient formation was detected. However, differences in medium viscosity significantly altered the mass transfer and mixing performance of the JLR.