Column flooding, gas holdup and interstage backmixing of an aerated multistage, mechanically-agitated, compartmented column

Column flooding, gas holdup and interstage backmixing of an aerated multistage, mechanically-agitated, compartmented (MSAC) column were studied in this work. These investigations were conducted in a two-stage MSAC column. The stage diameter and height were 24.27 cm and 24.13 cm, respectively. Each stage was fully baffled and the agitation was provided by a 6-bladed disk impeller positioned at the center of each stage. The air was fed into the column through a ring sparger which was positioned 4.45 cm beneath the impeller in the lower stage.;The gas holdup (;The interstage backmixing in an aerated MSAC column was also determined experimentally. The effects of impeller speed, impeller diameter and both superficial liquid velocity and superficial gas velocity through the interstage opening were investigated. Both the counter current and co-current flow of liquid and gas phases in the column were investigated. As gas velocity through the opening increased from zero the interstage backmixing significantly decreased initially, reached a minimum and increased slowly at high gas velocity. The effect of the gas flow on interstage backmixing was correlated in dimensionless form for a given liquid superficial velocity through the opening using the parameter N...