A ONE-DIMENSIONAL INSTATIONARY HETEROGENEOUS MASS-TRANSFER MODEL FOR GAS-ABSORPTION IN MULTIPHASE SYSTEMS

For a physically correct analysis (and prediction) of the effect of fi ne, dispersed phase drops or particles on the mass transfer rate in mu ltiphase systems, it was demonstrated that only 3-D instationary, hete rogeneous mass transfer models should be used. Existing models are eit her homogeneous, stationary or single particle models. As a first step , a 1-D, instationary, heterogeneous multi-particle mass transfer mode l was developed. With this model the influence of several system param eters was studied and problems and pitfalls in the translation of mode ling results for heterogeneous models into a prediction of absorption fluxes are discussed. It was found that only those particles located c losely to the gas;liquid interface determine mass transfer. For these particles the distance of the first particle to the gas-liquid interfa ce and the particle capacity turned out to be the most important param eters. Comparisons with a homogeneous model and experimental results a re presented. Typical differences in results comparing a homogeneous m odel with the 1-D heterogeneous model developed in this work could be attributed to a change in the near interface geometry. Future work in this field should therefore be directed towards near interface phenome na. Three dimensional mass transfer models, of which a preliminary res ult is presented, are indispensable for this. (C) 1998 Elsevier Scienc e S.A. All rights reserved.