Reactor with multiple-impeller agitator

Armenante, P.M. Huang, Y.-T. Li, T. Determination of the minimum agitation speed to attain the just dispersed state in solid-liquid and liquid-liquid reactors provided with multiple impellers. Chem. Eng. Sci. 1992, 47, 2865-2870. 

The agitator shaft is inclined from 0 to 45 with the vertical, and multiple impellers are used with longer reactors. 

Fig. 15. Reactor with a multiple-agitator arrangement. 1, turbine impeller 2, baffle 3, cooling and heating coils 4, perforated ring for hydrogen supply. (Bern et al., 1976 also from Chaudhari et al., 1986, by courtesy of Marcel Dekker, Inc.)...

In the conventional mechanically agitated reactors, poor dispersion is likely to occur in large units, particularly near the bottom. This can be overcome by using a large L/dT ratio with a horizontal arrangement and multiple impellers. 

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