Hydrodynamic study of a downwards concurrent bubble column

Marchese Mecklenburg, Mario; Marchese Mecklenburg, Mario

Thesis

Hydrodynamic study of a downwards concurrent bubble column

Public Deposited

Analytics

Download PDF

Creator

Marchese Mecklenburg, Mario

Abstract

English

The hydrodynamics of the downwards concurrent flotation column (CDFC) of the Jameson design has been studied. The effect of operating variables on the gas holdup in two- and three-phase mixtures was measured. To measure gas holdup, the isolating technique, conductivity and pressure techniques were employed. Gas fractions between 10 and 65% were achieved. These high holdups are a consequence of bubbles being forced downwards against their buoyancy. The high gas fraction may account for the fast flotation claimed for this cell. The conductivity technique using Maxwell's equation gave a maximum error of 6%, in both two- and three-phase systems (considering the water-solids mixture as one phase). The drift flux model was applied to try to correlate the data. Both two- and three-phase systems showed consistent trends. The model was used to estimate bubble size. In the Richardson and Zaki equation the m factor was in the range 2.9 to 3.1. A dimensionless drift flux was defined assuming $m=3$ which fitted the data. For three-phase systems, however, the results predicted a trend in bubble size that seemed opposite to observation. (Abstract shortened by UMI.)

Last modified