Gas-liquid mass transfer in a multi-stage perforated-disk type stirring cascade

Abstract

Experimental study is conducted to determine interphase mass transfer of a solute (carbon dioxide) in gas-liquid systems (air and water) in counter-current flow through a three-stage perforated-disk type stirring cascade. Test results over the entire cascade can be correlated as wherein NTU, jD and g are the number of transfer unit, modified mass transfer factor and gas flow rate, respectively, based on the liquid phase (f). The subcript [infinity] denotes an asymptotic value. The criterion corresponding to the state of overflow limit is determined by a certain value of the separation factor A (using the subscript fl for overflow limit) beyond which the stirrer is flooded with the gas resulting in undersirable dispersion and high power requirement. Within the range of A = Afl, the overall mass-transfer performance may be predicted by NTUf = jDfSc-2/3f = 1.03 x 10-4A0.6Re0.449r in which Scf is the liquid-phase Schmidt number and Rer expressed the impeller (disk) Reynolds number.