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Dynamic pressure method for k l a measurement in large‐scale bioreactors
Author(s) -
Linek V.,
Beneš P.,
Vacek V.
Publication year - 1989
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260331107
Subject(s) - dispersion (optics) , oxygen , mixing (physics) , aeration , bioreactor , chemistry , thermodynamics , analytical chemistry (journal) , limiting oxygen concentration , mechanics , materials science , chromatography , physics , organic chemistry , quantum mechanics , optics
Abstract A dynamic method is proposed for k l a measurement in aerated and agitated reactors, in which a change in the total pressure in the reactor by approximately 20% leads to a simultaneous change in the oxygen concentration in all the bubbles in the dispersion. This procedure suppresses the influence of nonideal mixing of the gas phase on the k l a value. Other dynamic methods so far used do not possess this advantage. They are based on a step change in oxygen concentration in the entering gas, where the interfacial nitrogen transport and the finite rate of the concentration change propagation into the individual bubbles in the dispersion can cause an error in the reported k l a values of more than hundreds of percent. The reliability of the pressure method is tested by comparison both with the standard dynamic method, in which pure oxygen is absorbed in a liquid from which all other gas components were previously removed, and with the steady‐state sulphite method. The signal of the oxygen probe used in the experiments must be independent of the pressure. A test for this in dependence is described. The pressure method is also suitable for large‐scale reactors since the necessary pressure changes are sufficiently small and, morever, air can be used.