Abstract
Volumetric gas-liquid mass transfer coefficients were measured in suspensions of cellulose fibers with concentrations ranging from 0 to 20 g/L. The mass transfer coefficients were measured using the dynamic method. Results are presented for three different combinations of impellers at a variety of gassing rates and agitation speeds. Rheological properties of the cellulose fibers were also measured using the impeller viscometer method. Tests were conducted in a 20 L stirred-tank fermentor and in 65 L tank with a height to diameter ratio of 3:1. Power consumption was measured in both vessels. At low agitation rates, two Rushton turbines gave 20% better performance than the Rushton and hydrofoil combination and 40% better performance than the Rushton and propeller combination for oxygen transfer. At higher agitation rates, the Rushton and hydrofoil combination gave 14 and 25% better performance for oxygen transfer than two Rushton turbines and the Rushton and hydrofoil combination, respectively.
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Abbreviations
- kLa:
-
gas liquid mass transfer coefficient (s-1)
- Cg :
-
gas side concentration
- cL :
-
liquid side concentration
- CE(0):
-
electrode response at time = 0
- CE(T):
-
electrode response at time = t
- φ:
-
dimensionless electrode response
- α:
-
Henrys law coefficient
- τt1 :
-
time constant
- τ2 :
-
time constant
- τd:
-
dead time
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Dronawat, S.N., Svihla, C.K. & Hanley, T.R. Effect of impeller geometry on gas-liquid mass transfer coefficients in filamentous suspensions. Appl Biochem Biotechnol 63, 363–373 (1997). https://doi.org/10.1007/BF02920438
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DOI: https://doi.org/10.1007/BF02920438