Bioprocess Engineering

, Volume 19, Issue 1, pp 37–44 | Cite as

Concentric-tube airlift bioreactors

Part I: Effects of geometry on gas holdup
  • M. Gavrilescu
  • R. Z. Tudose


Gas holdup investigations were performed in three concentric-tube airlift reactors of different scales of operation (RIMP: 0.070 m3; RIS-1: 2.5 m3; RIS-2: 5.2 m3; nominal volumes). The influences of the top and bottom clearances and the flow resistances at the downcomer entrance were studied using tap water as liquid phase and air as gaseous phase, at atmospheric pressure. It was found that the gas holdup in the individual zone of the reactor: riser, downcomer and gas-separator, as well as that in the overall reactor is affected by the analyzed geometrical parameters in different ways, depending on their effects on liquid circulation velocity. Gas holdup was satisfactorily correlated with Fr, Ga, bottom spatial ratio (B), top spatial ratio (T), gas separation ratio (Y) and downcomer flow resistance ratio (A d /A R ). Correlations are presented for gas holdup in riser, downcomer, gas separator and for the total gas holdup in the reactor. All the above stressed the importance of the geometry in dynamic behaviour of airlift reactors.


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Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • M. Gavrilescu
    • 1
  • R. Z. Tudose
    • 2
  1. 1.Research Center for Antibiotics, Chemical-Pharmaceutical Research Institute, 6647 Valea Lupului 1, Jassy, RomaniaRO
  2. 2.Department of Transfer Phenomena and Chemical Engineering, Faculty of Industrial Chemistry, Technical University of Jassy, Mangeron Street 71, 6600 Jassy, RomaniaRO

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