title: Effect of impeller geometry on gas-liquid mass transfer coefficients in filamentous suspensions.
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.
authors.affiliation: Department of Chemical Engineering, Speed Scientific School, University of Louisville, 40292, Louisville, KY.
authors.forename: S N
authors.initials: SN
authors.lastname: Dronawat
authors.forename: C K
authors.initials: CK
authors.lastname: Svihla
authors.forename: T R
authors.initials: TR
authors.lastname: Hanley