3.2. Different number of impellers
Measurements in model media (Sieblist et al., 2011b) showed
that the oxygen mass transfer in an aerated stirred tank reactor
may depend on the number of impellers employed. At the same
power input, they found larger kLa values in an aerated stirred
tank agitated with two impellers than in the same reactor equipped
with three impellers. This fact, not predicted by the standard correlations,
has to be investigated in cultivation experiments. For
that purpose fermentations were performed with both impeller
arrangements.