ISSN:
0006-3592
Keywords:
oxygen absorption
;
mass transfer coefficient
;
pilot-plant fermentor
;
dynamic pressure method
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
The dynamic pressure method (DPM) is used for measurement of kLa in a 1-m3 pilot scale fermentor in coalescing (distilled water) and noncoalescing (0.3 M Na2SO4 aqueous solution) batches. The method consists in recording oxygen concentration in a batch after a small pressure change (20 kPa) in the fermentor. The upward pressure change is brought about by temporary closing and subsequent throttling of outlet gas stream and the downward change by full reopening of the gas outlet. Absorption of pure oxygen yields the same kLa values as absorption of air. In noncoalescing batch, the downward kLa values are always higher than the upward values owing to spontaneous nucleation of bubbles. The experiments performed in a stirred cell confirm this behavior. Thus, only upward pressure change should be used for measurement. The correlation of kLa data measured in small (18-L) and large (1000-L) vessels based on power dissipated and superficial gas velocity are in a good agreement. Unlike the DPM, the classical dynamic methods yield, under the same conditions, excessively low values of kLa (the dynamic startup method) or fail to produce data at all (the dynamic method with interchange of air for N2). © 1994 John Wiley & Sons, Inc.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bit.260430607
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