Hydrodynamics of countercurrent two-phase flow in a centrifugal field

Centrifugal adsorption technology (CAT) is a new method for continuous adsorption and ion exchange involving countercurrent flow of liquid and micrometer‐range adsorbent particles under the influence of a centrifugal force. Due to the fast adsorption kinetics associated with very small particles, CAT leads to extremely compact separation equipment with high capacities and excellent mass‐transfer efficiencies. Experimental results on the hydrodynamics of countercurrent flow of solids and liquid in a centrifugal field are discussed in terms of flooding conditions, pressure drops and holdup of the adsorbent particles in the contactor. A model developed based on the relations for homogeneous fluidization under gravity correctly describes countercurrent flow under gravity, but does not correctly describe countercurrent flow in a centrifugal field. In general, observed capacities of this model are higher than estimated. Although the centrifugal force magnifies the apparent density difference between the two phases, the two‐phase flow did not seem to exhibit heterogeneous behavior, such as observed in gas‐fluidized beds.