Falling liquid film stability in microgas/liquid absorption

Abstract

Increasing mass transfer efficiencies is reached in G/L absorption contactors thanks to stabilization of the liquid flow. Hydrodynamic studies about the stability of a liquid film thickness are carried out to explain variations of mass transfer efficiencies during absorption experiments. These studies are based on the analytical expression developed by Hobler (1964) [1] which enables to predict the minimum wetting rate (MWR) and the minimum liquid film thickness (MLFT). Experiments were carried out to validate the prediction of the hydrodynamic model for a specific chemical system (absorption of tetrachloroethylene in di-ethyl-hexyl adipate). Therefore, two microstructured plates have been investigated in comparison to an unstructured plate. The plates have been embedded in a miniaturized falling film absorber. A strong influence of the geometry on the mass transfer efficiency is found, especially at low liquid flow rates where dry zones decrease the interfacial specific area which differs from the specific surface of the solid support.