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In designing extraction columns many parameters must be considered such as dispersed phase local hold up. Prediction of dispersed phase hold up is one of the most important parameters in design. A laboratory spray and RDC columns are constructed for the experimental works. The selected chemical systems for no mass transfer experiments were Water- Toluene, water-normal Heptane and Water-MIBK, with a variety of physical properties interfacial tension, viscosity and density. In all experiments, the oil phase was as dispersed phase and water phase as continuous phase. According to the experiments, it was found that dispersed phase local hold up increases in the columns as dispersed phase volumetric flow rate at a fixed continuous flow rate increases. As interfacial tension increases the dispersed phase local hold up in the columns increases
as well. Static hold up can be neglected in spray columns because of no internal equipment's in the column although it is a little in the RDC column. Local hold up at different height of the columns is measured and analyzed. Series of experiments have been carried out 111 above-mentioned columns.