Bioprocess Engineering

, Volume 16, Issue 2, pp 93–99

Hydrodynamics in external-loop airlift bioreactors with static mixers

  • M. Gavrilescu
  • R. V. Roman
  • R. Z. Tudose

DOI: 10.1007/s004490050294

Cite this article as:
Gavrilescu, M., Roman, R. & Tudose, R. Bioprocess Engineering (1997) 16: 93. doi:10.1007/s004490050294

Abstract

 Liquid circulation superficial velocity and gas holdup behaviours were investigated in an external-loop airlift bioreactor of 0.170 m3 liquid volume in gas-induced and forced-circulation-loop operation modes, in the presence of static mixers made of corrugated stainless steel pieces, resulting in packets with the height-to-diameter ratio equal to unity and using non-Newtonian starch solutions as liquid phase. The static mixers were disposed in the riser in three blocks, each with three mixing packets, successively turned 90° to the adjacent mixing element. It was found that in the presence of static mixers and forced-loop operation mode, liquid circulation superficial velocity in the riser section was significantly diminished, while gas holdup increased in a great measure. It was considered that static mixers split the fluid into individual streams and break up the bubbles, resulting in small bubble sizes with a relative homogeneous bubble distribution over riser cross section. They act as supplementary resistances in liquid flow, reducing riser cross sectional area, equivalent with AD/AR area ratio diminishing.

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • M. Gavrilescu
    • 1
  • R. V. Roman
    • 1
  • R. Z. Tudose
    • 2
  1. 1.Chemical Pharmaceutical Research Institute, Research Center for Antibiotics 6647 – Valea Lupului no. 1, IASi, RomaniaRO
  2. 2.Department of Transfer Phenomena and Chemical Engineering, Faculty of Industrial Chemistry of Technical University of IASI 6600-Mangeron Str. no. 71, IASi, RomaniaRO