ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

An Efficiency of the Liquid Homogenization in Agitated Vessels Equipped with Off-Centred Impeller

J. Szoplik and J. Karcz

Department of Chemical Engineering, Faculty of Chemical Engineering Szczecin University of Technology, PL-71 065 Szczecin

E-mail: joanka@ps.pl

Abstract: Efficiency of the liquid homogenization in agitated vessels (with inner diameter D) equipped with off-centred impeller is analyzed. Experimental studies of the mixing time were carried out in a 0.270 m³ vessel using unsteady-state thermal method. Eccentrically located propeller and pitched blade turbines were used for agitation of Newtonian liquid (aqueous solution of molasses) within the turbulent regime of the fluid flow. Assuming constant value of the specific mixing energy, ε, similar values of the mixing times, tm, were observed for propeller and pitched blade turbine with three blades. Mixing time was positively influenced by the increase of impeller diameter and the number of impeller blades. Assuming constant value of specific energy, ε, the lowest dimensionless mixing time, Θ, corresponded to the eccentric pitched three-blade turbine with diameter d = 0.5 D. Taking into account different criteria proposed in literature, eccentric propeller (e/R = 0.57) can be recommended for liquid homogenization with the most efficiency in the unbaffled agitated vessel, within the range of the performed measurements.

Full paper in Portable Document Format: 596aa373.pdf

Chemical Papers 59 (6a) 373–379 (2005)