Micromixing effects in aerated stirred tank

Micromixing efficiency in an aerated stirred tank is measured quantitatively on the basis of a new parallel competing reaction scheme proposed by Villermaux and co-workers. The segregation index is strongly influenced by both mechanical stirring and gas-flow agitation. In the region near the impeller tip, the agitation by bulk gas column or dispersed tiny bubbles can provide an efficient micromixed environment. Stirring effect becomes secondary. In the near-wall regions far from tip, however, the occurrence of flooding markedly reduces the micromixing efficiency. Possible role of bubbles on agitation is discussed. (C) 1997 Elsevier Science Ltd.