The hydrodynamics or gas‐liquid contacting in towers with fluidised packings

Abstract

Abstract A model is developed of gas liquid contactors in which packing pieces are maintained in the fluidized state. The model proposes that the column can exist in either of two modes, namely fluidisation without flooding and fluidisation due to incipient flooding. The mode of operation established depends primarily on the packing density and to a lesser extent on the packing size, liquid flow and liquid properties. Equations predicting the transition from one mode to the next are developed. The inherent advantages of operating in the “incipient flooding” mode are stressed. It is argued that the pressure build up associated with flooding will be sufficient to support the weight of packing pieces and the liquid in the column. At this stage, rather than reject counter current flow (true flooding) the bed expands to maintain a state of incipient flooding. In this way counter current flow can be maintained in a situation well above the normal flooding point. This explains the high performance of such units.