DYNAMIC LIQUID HOLDUP AND OXYGEN MASS-TRANSFER IN A COCURRENT UPFLOW BIOREACTOR WITH SMALL PACKING AT LOW REYNOLDS-NUMBERS

An experimental investigation of dynamic liquid holdup and oxygen abso rption mass transfer was carried out in a laboratory bioreactor packed with expanded clay balls. The column was operated with a cocurrent up flow of air and water at low Reynolds numbers. The data obtained for d ynamic liquid holdup have been represented by a modified Stiegel-Shah relation with a relative mean error of 0.7%. For prediction of the oxy gen mass transfer coefficient, an empirical correlation based on air a nd water mass superficial velocities has been proposed. It reproduced our experimental results with a relative mean error of 9%. Both correl ations proposed in this study are valid for small packing spheres arou nd 2.7 mm in diameter and Reynolds numbers varying for gas and liquid from 0.197 to 0.593 and from 3.875 to 9.315 respectively.