Effect of Impeller Geometry on Gas-Liquid Mass Transfer Coefficients in Filamentous Suspensions
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.
Index EntriesFilamentous Suspensions Gas-liquid mass transfer non-Newtonian rheology
Unable to display preview. Download preview PDF.
- 1.Moo-Young, M. and Blanch, H. W. (1981), Adv. Biochem. Eng. 19 1–69.Google Scholar
- 3.Svihla, C. K. and Hanley, T. R. (1992), AIChE Symposium Series, 88114–118.Google Scholar
- 6.Linek, V., Vacek, V., and Benes, P. (1988), Chem Eng. J. 34 11.Google Scholar
- 7.Dronawat, S. N, (1996), Mixing in Fermentors: Analysis of Oxygen Transfer and Rheology, Ph. D. Dissertation, University of Louisville.Google Scholar