MEASUREMENT AND CORRELATION OF PACKED-BED AXIAL-DISPERSION COEFFICIENTS IN SUPERCRITICAL CARBON-DIOXIDE

Axial dispersion coefficients of squalene, benzoic acid, and oleic aci d were measured in packed beds using supercritical carbon dioxide as a solvent over the temperature range 313-333 K, pressure range 100-300 bar, and Reynolds number range 2-80. Measurements were performed under both horizontal and vertical flaw conditions, using a variety of part icle sizes, bed diameters, and bed lengths. The axial Peclet numbers o btained for small particles (< 1 mm diameter) were an order of magnitu de lower than literature data for gases and liquids at ambient pressur es. The dimensionless correlation 1/Pe = 0.018/Re + 10/(1 + 0.7/Re) wa s found to correlate the data within experimental error. The dispersio n coefficients for large particles (> 1 mm) could be satisfactorially predicted by literature correlations.