EFFECT OF GAS-LIQUID FLOW MODE AND COLUMN DIAMETER ON GAS HOLDUP AND GAS-LIQUID INTERFACIAL AREA IN BUBBLE COLUMN

Bubble columns of 5000 mm height and seven diameters (50, 70, 94, 114, 164,200 and 280mm) were employed for visual observations of flow patterns and measurements of gas holdup and gas-liquid interfacial areas, under gas and liquid flow conditions covering the ranges of cocurrent upflow, countercurrent flow and cocurrent downflow. Air was used as gas and tap water and sodium sulfate solution were used as liquid medium. Gas-liquid interfacial areas were determined by using sodium sulfite oxidation reaction. When column diameter or liquid species was changed, flow pattern transition occurred at different gas and liquid velocities, and the transitions were judged by gas-liquid slip velocities. Experimental correlations of gas holdup were derived for bubble flow and churn turbulent flow. In every gas-liquid flow mode, no effect of column diameter on gas holdup was observed beyond 140 mm column diameter. Gas-liquid interfacial areas strongly depended on gas holdup, and this dependency in bubble flow regime was different from that in churn turbulent flow regime. © By THE SOCIETY OF CHEMICAL ENGINEERS, JAPAN.