Abstract
A gas–liquid two-phase plunging jet is formed through an ejector type nozzle using a perforated plate. Absorbers that use such a jet have a high gas holdup and a large product of liquid-phase mass transfer coefficient and gas–liquid interfacial area, (k̅LA)T. In the present study, the dependence of the gas holdup and bubble diameter on the nozzle geometry and column diameter was investigated experimentally. An equation for the gas holdup was derived based on physical considerations. The mass transfer mechanism for all of the experimental data was analyzed using a coaxial bi-zonal model. The dependence of the liquid phase mass transfer coefficient k̅LT and specific gas–liquid interfacial area aT on the column diameter DT was evaluated. The gas holdup was found to be a function of the equivalent diameter de; total energy of the liquid jet, ET; and DT. The behavior of this absorber can be explained using the coaxial bi-zonal model across all of the data. The (k̅La)T value for the plunging jet absorber can be enhanced by decreasing DT; further, aT showed a weak dependence on DT. The changes in k̅LT were influenced by an increase in the ratio of the gas–liquid interfacial area in the peripheral annular zone to that in the core zone. Therefore, the changes in (k̅La)T against the energy loss per unit volume of liquid, ET/VL, were dependent on the changes in (k̅La)T with ET/VL. The design of the plunging jet absorber showed that a nozzle diameter DN of 1 cm and DT of 5 cm were desirable under the experimental conditions.
