Measurement and Correlation of Packed-Bed Axial Dispersion Coefficients in Supercritical Carbon Dioxide

摘要

Axial dispersion coefficients of squalene, benzoic acid, and oleic acid 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 flow conditions, using a variety of particle sizes, bed diameters, and bed lengths. The axial Peclet numbers obtained for small particles (< 1 mm diameter) were an order of magnitude lower than literature data for gases and liquids at ambient pressures. The dimensionless correlation 1/Pe = 0.018/Re + 10/(1 + 0.7/Re) was found to correlate the data within experimental error. The dispersion coefficients for large particles ( >1 mm) could be satisfactorially predicted by literature correlations.