Mass transfer and hydrodynamic characteristics of gas inducing type of agitated contactors

Abstract

Power consumption, rate of gas induction (Q), fractional gas hold-up and mass transfer characteristics of 0.41, 0.57 and 1.0 m i.d. gas inducing type of agitated contactors were studied. The power consumption was measured by a torque table. The values of effective interfacial area (a), and liquid side mass transfer coefficient (k_La) were obtained by using chemical methods. Two types of impellers (pipe and flattened cylindrical) were employed. The impeller speed was varied from 3 to 11.7 r/s. The effects of impeller diameter, baffle position, orifice area on the impeller, number of impeller blades, position of impeller from the bottom and liquid submergence on the values of Q and a were investigated. Further, the effect of liquid viscosity and surface tension on the values of Q was studied. A satisfactory agreement was found between the observed and the predicted value of the minimum impeller speed at which gas induction occurs. The performance of the gas inducing type of agitated contactor has been compared with the conventional mechanically agitated contactor.