A comparative study of gas holdup, bubble size distribution and interfacial area in a downflow bubble column

Experimental investigations have been carried out in an ejector induced downflow bubble column with special emphasis on gas holdup, bubble size distribution and interfacial area. Bubble diameters have been measured by photographic and capillary method at different operating conditions. Bubble sizes are found to have a logarithmic-normal probability distribution for any axial positions of the column. Sauter mean bubble diameters have been used along with overall gas holdup to get the geometric interfacial area and the results are compared with the interfacial area obtained by chemical method. Experiments are carried out with air-water system in bubbly flow regime. Absorption of carbon dioxide in aqueous sodium hydroxide solution has been adopted to measure interfacial area by chemical method. The discrepancies in interfacial area obtained by the two methods are found to be consistent with reported works.