Stirred-tank mechanical power requirement and gas holdup in aerated aqueous phases

✍ Scribed by Ibrahim T. M. Hassan; Campbell W. Robinson

• Publisher: American Institute of Chemical Engineers
• Year: 1977
• Tongue: English
• Weight: 1015 KB
• Volume: 23
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690230109

✦ Synopsis

Abstract

Gas holdup and the ratio of the turbulent regime mechanical power consumed in aerated compared to that in nonaerated aqueous phases were measured in two laboratory sized tanks. Standard six‐blade turbine (D/T = 1/3), six‐blade paddle (D/T = 1/3), and four‐blade paddle (D/T = 2/3) impellers were used over a wide range of impeller rotational speed and gas sparging rate. For all systems, the power ratio results were found to fit a semitheoretical correlation (derived from dimensional analysis) involving the impeller Weber number, the aeration number, and the ratio of dispersion and liquid densities. Empirical correlations for gas holdup in water, aqueous solutions of nonelectrolytes, and an aqueous electrolyte solution are given. The overall results lead to the conclusion that power ratio and gas holdup correlations are highly specific to a particular impeller type and are also dependent on the tank size and the liquid phase physicochemical properties.