Experimental study of the flooding and appearance of a bubble bed on top of a countercurrent packed-bed column

This paper presents an experimental study of the countercurrent packed-bed column in the course of flooding and above the flooding point when the colu mn operates as a packed bed and a bubble bed in series. Pressure-drop and l iquid-holdup data are presented for the packed- and bubblebed parts of the system. The experiments show that for the two beds in series the hydrodynam ic conditions within the packed-bed part are similar for various gas-liquid velocity conditions. The pressure drop in the initial stage of flooding is essentially independent of gas-liquid velocities. The porosity of the form ing bubble bed is initially high/low for high/low liquid velocities, For ex panded bubble beds their porosity increases with increasing gas velocities.