Open AccessImpact of nozzle operation on mass transfer in jet aerated loop reactors. Characterization and comparison to an aerated stirred tank reactor
Author(s) -
Weber Sebastian,
Schaepe Sebastian,
Freyer Stephan,
Kopf MichaelHelmut,
Dietzsch Christian
Publication year - 2018
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.201800008
Subject(s) - aeration , continuous stirred tank reactor , mass transfer , bioreactor , mass transfer coefficient , nozzle , jet (fluid) , mixing (physics) , oxygen , materials science , chemical engineering , mechanics , chemistry , chromatography , thermodynamics , physics , engineering , organic chemistry , quantum mechanics
Abstract The impact of mass transfer on productivity can become a crucial aspect in the fermentative production of bulk chemicals. For highly aerobic bioprocesses the oxygen transfer rate (OTR) and productivity are coupled. The achievable space time yields can often be correlated to the mass transfer performance of the respective bioreactor. The oxygen mass transfer capability of a jet aerated loop reactor is discussed in terms of the volumetric oxygen mass transfer coefficient k L a [h −1 ] and the energetic oxygen transfer efficiency E [kgO 2 kW −1 h −1 ]. The jet aerated loop reactor (JLR) is compared to the frequently deployed aerated stirred tank reactor. In jet aerated reactors high local power densities in the mixing zone allow higher mass transfer rates, compared to aerated stirred tank reactors. When both reactors are operated at identical volumetric power input and aeration rates, local k L a values up to 1.5 times higher are possible with the JLR. High dispersion efficiencies in the JLR can be maintained even if the nozzle is supplied with pressurized gas. For increased oxygen demands (above 120 mmol L −1 h −1 ) improved energetic oxygen transfer efficiencies of up to 100 % were found for a JLR compared to an aerated stirred tank reactor operating with Rushton turbines.