Volumetric mass transfer coefficient in multiple-impeller gas–liquid contactors. Scaling-up study for various impeller types

• Experimental kLa data for pilot-plant gas–liquid contactor are presented.
• Experimental kLa data for various impeller types are presented.
• Scaling-up based on volumetric mass transfer coefficient is precised.
• Using various impeller types, the kLa correlations suitable for scaling-up are developed.
• The simplified kLa correlation was developed without using impeller power.

Focused on liquid film-controlled processes in mechanically agitated aerated vessels, an attempt is made to develop scale-up correlations based on isotropic turbulence theory. It is shown that including the impeller tip speed fD (impeller frequency * impeller diameter) in data treatment significantly improves the volumetric mass transfer coefficient (kLa) prediction abilities in scaling-up applications. Additionally, simplified correlation is developed, which evades the need of impeller power knowledge. Its good usability for kLa prediction is shown except for the case when common correlation is made together for axial and radial impellers. The study is based on measurements of volumetric mass transfer coefficient in a pilot scale multiple-impeller vessel with non-coalescent batch and six various impeller types, which expand previous data set from a laboratory scale tank.