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The influence of vessel height and top‐section size on the hydrodynamic characteristics of airlift fermentors
Author(s) -
Russell A. B.,
Thomas C. R.,
Lilly M. D.
Publication year - 1994
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.260430110
Subject(s) - airlift , section (typography) , mechanics , biology , bioreactor , physics , computer science , botany , operating system
Fermentations of the yeast Saccharomyces cerevisiae were carried out in a 90 to 250‐L working volume concentric tube airlift fermentor. Measurements of liquid circulation velocity, gas hold‐up, and liquid mixing were made under varying conditions of gas flowrate, vessel height, and top‐section size. Both liquid circulation velocity and mixing time increased with vessel height. Liquid velocity varied approximately in proportion to the square root of column height, supporting a theoretically based relationship. The effect of vessel height on gas hold‐up was negligible. The height of the top‐section had a significant effect on liquid mixing. Mixing time decreased with increasing size of the top‐section up to a critical height. As the top‐section was expanded beyond this height, little improvement in mixing was seen. This indicated the presence of a two‐zone flow pattern in the top‐section. Liquid velocity and gas hold‐up were essentially independent of top‐section height. © 1994 John Wiley & Sons, Inc.