COMPRESSIVE STRESSES AND TRANSPORT FORCES IN HYDRAULIC PACKED-BED WASH COLUMNS

Hydraulic packed bed wash columns are continuous solid-liquid separato rs, which combine a virtually complete crystal-mother liquor separatio n with a highly efficient washing action at high throughput. The appli cability of this type of wash column, i.e. for large-scale ultrapurifi cation of organic crystals, depends amongst others on the compressive stresses that are exerted on these crystals upon processing in a hydra ulic wash column. In this paper an analytical model is presented which can be used in technical feasibility and scale-up studies to predict the compressive stress profiles that occur in a hydraulic wash column during operation. From calculations based on experimental data, rules were derived on how to minimize the compressive stresses during the op eration of a hydraulic wash column.