COCURRENT DOWNFLOW BUBBLE COLUMN WITH SIMULTANEOUS GAS-LIQUID INJECTION NOZZLE

Flow characteristics of the downflow bubble column with a simultaneous gas-liquid injection nozzle were experimentally investigated. The flow pattern was observed and ranges of stable cocurrent downflow operation were examined. Gas holdup and specific gas-liquid interfacial area were measured. When the simultaneous gas-liquid injection nozzle was used in the downflow bubble column, spouting and calm sections were observed to appear in the column. In the spouting section, gas holdup was higher and interfacial area was larger than those in the calm section. In comparison with the results for the perforated sparger, the bubble diameter was smaller and the range of stable cocurrent downflow operation was wider. In addition, it was found that, under a specified condition, the gas holdup was lower and the interfacial area was larger than those in the case of the perforated sparger, and that such differences became more marked with decreasing nozzle diameter and with increasing liquid velocity.