Influence of Spacing of Multiple Impellers on Power Input in an Industrial‐Scale Aerated Stirred Tank Reactor

Despite the fact that aerated stirred tank reactors are widely used in industry and often studied, their design and scale‐up still remains challenging. Especially the specific power input is a crucial and geometry‐dependent scale‐up parameter, usually calculated with the dimensionless power number Po. Within the scope of this study, the power number is measured for different stirrer types and configurations in a laboratory and an industrial‐scale aerated stirred tank reactor. Good agreements to literature are found for the unaerated case for the two‐stage stirrer configurations at different stirrer spacing for both scales. By literature only the aerated case in the laboratory scale can be predicted. Scale‐up of an aerated industrial‐scale reactor is challenging because of a specific influence of the aeration. In case of a three‐stage Rushton configuration, an asymmetrical distribution of the stirrers should be preferred to ensure a high power number as well as good power performance under aerated conditions.