The effects of operating parameters on stage efficiency in an Oldshue-Rushton column

Abstract

In this research, stage efficiency has been measured in a 113 mm Oldshue-Rushton column for two systems including toluene-acetone-water and n-butyl acetate-acetone-water. The experiments performed in two directions of mass transfer. The effects of different parameters such as rotor speed, dispersed and continuous phase velocities and direction of mass transfer on the stage efficiency were investigated. The experimental data show that the stage efficiency is strongly dependent on the agitation rate and interfacial tension, but only slightly dependent on phase velocities. It was observed that the stage efficiency is better when the mass transfer direction of acetone is from the continuous to the dispersed phase in comparison to opposite direction due to the presence of oscillations created by surface tension gradient. The investigated column is one of the extraction columns with high stage efficiency. An empirical correlation is proposed to describe the stage efficiency in terms of Reynolds and Froude numbers. The predictions of the equation had good agreement with the experimental data.