The separation efficiency of packed columns is strongly influenced by hydrodynamics. It is therefore of importance in the design of packed columns the estimation of parameters such as liquid holdup (both dynamic and static), pressure drop and flooding point. In this field, there is a large number of experimental results published for low pressure applications. However, data for high-pressure systems is relatively scarce. In this work, hydrodynamic data was experimentally obtained in a 7.5-m tall, 40 mm i.d. column. In the experiments, the separation of free fatty acids from vegetable oils was studied. Separation efficiency, and static and dynamic holdup were determined for various packing materials (random and structured) at several operating conditions. Through experiments with a carotene tracer, the residence time distribution was measured. Several known correlations, which take into account the buoyancy effect of dense gases, were applied to the experimental data, and good agreement with the results of other authors was observed. (C) 2008 Elsevier B.V. All rights reserved.