Effects of process conditions on foaming in stirred tanks

Joelle Aubin (1) , D. Daniel , A Deu , C Raffel , W Shaikh , E Rundquist , P M Piccione

1 LGC - Laboratoire de Génie Chimique

The effect of impeller speed and type, as well as gas flow rate on the amount of foam generated in a 5L stirred tank has been studied. Foam height was found to increase with increasing impeller speed after a critical impeller speed was reached. It also increased with increasing gas flow rate. The disc turbine creates significantly more foam than the down-pumping hydrofoil for a given tip speed. Scale-up guidance to correctly replicate the amount of foaming in larger scale tank was also investigated. It was found that impeller tip speed was the best scale-up invariant, compared with power per unit volume and the Weber and Froude numbers. It is less clear, however, which is the best scale-up invariant for the gas flow rate; aeration number appears more adapted than the superficial gas velocity or the ratio of gas flow rate to liquid volume, however it does not always correctly replicate the gas-liquid flow regime.

Mots clés: stirred tank; gas-liquid; foaming; scale-up

Domaines: Génie chimique; Génie des procédés

Joelle Aubin, D. Daniel, A Deu, C Raffel, W Shaikh, et al.. Effects of process conditions on foaming in stirred tanks. 16th European Conference on Mixing, Sep 2018, Toulouse, France. ⟨hal-02373259⟩