Dispersion kinetics in mechanically agitated vessel

Agitation of two immiscible liquids or solid-liquid suspension is a frequent operation in chemical and metallurgical industries. Prediction of mean drop/particle size and drop/particle size distribution (DSD) is vital for emulsification, suspension polymerization, solid particle dispersion or crystallization. Simulation of particulate systems requires the knowledge of DSD and its time evolution. The time evolution of drop size distribution was investigated in baffled vessel mechanically agitated by a Rushton turbine and a high-shear tooth impeller. The system water-silicone oil was used as a model liquid. The volume fraction of the dispersed phase was 0.047 %. The drop sizes were determined by image analysis. The time evolution of the drops size d(p32) was studied for both impellers tested. The model used involves the first order kinetics. Finally, the following correlations predicted by the Kolmogorov-Hinze theory were evaluated at steady state: d(p32)/D = C-1.We(-0.6) and d(pmax)/D = C-2.We(-0.6), where We is the impeller Weber number.