Application of CFD in the study of supercritical fluid extraction with structured packing: Dry pressure drop calculations

Liquid phase SFE has been carried out in extraction columns, with structured packings particularly of the gauze type. Structured packing performs very well during extractions under these conditions, mainly due to their relatively large surface area and free volume. Nevertheless, there are also important disadvantages such as high cost, low capacities at high flow rates, and premature flooding. The assessment of the real efficiencies of these packings poses extreme difficulties related to the moderately high pressures involved in these processes. Computational fluid dynamics (CFD) can be used to characterize the complex single and multiphase flow inside the packed bed and evaluate the influence of the shape and geometry of the packing on the hydrodynamics and mass and heat transfer rates in the SFE packed column. In this first study, and with a very detailed modelling of the packing geometry, the dry pressure drop is calculated for both laminar and turbulent flow conditions. Results are seen to agree well with the experimental data in the literature.