Measurement of Liquid-Liquid Dispersion Phenomena

in a Stirred Vessel using Electrical Resistance Tomography

M. Kaminoyama1,*, K. Nishi1, R. Misumi1, A. Tagawa2

1. Department of Materials Sciences and Chemical Engineering, Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai Hodogaya-ku Yokohama-shi 240-8501 JAPAN

2. Department of Materials Sciences and Chemical Engineering, Graduate School of Engineering, Yokohama National University, 79-5 Tokiwadai Hodogaya-ku Yokohama-shi 240-8501 JAPAN

*. Tel and Fax: 81-45-339-3999, *E-mail: kamin@ynu.ac

ABSTRACT

The liquid-liquid dispersion phenomena, including phase separation and phase inversion, in a stirred vessel are very complicated and crucial to suspension polymerization, as well as to emulsion polymerization. Many studies of these phenomena have been reported, but the visualization methods usually used, such as sampling or single point measurements, are unsatisfactory, and the understanding of these phenomena has been inadequate. On the other hand, the electrical resistance tomography technique makes it possible to obtain abundant information on multiphase phenomena in a stirred vessel in a non-intrusive and cross-sectional way. The electrical resistance tomography technique was, therefore, applied to a stirred vessel to observe the dispersion of a liquid into another immiscible liquid system. Firstly, the relation between the oil droplet dispersion process and the operating conditions of the mixing in a styrene-water system in a stirred vessel was investigated to obtain the equation regarding the stable dispersion time. Subsequently, a phase inversion phenomenon was observed in the styrene-water system in a stirred vessel using electrical resistance tomography. It was found that the phase inversion phenomenon occurred over a very short time and that the phenomenon proceeded in such a way that the volumetric fraction of the water phase became larger in the vicinity of the vessel wall, and then, the water phase entered into the center of the vessel.

Keywords Dispersion State, Phase Inversion, Liquid-Liquid Systems, Stirred Vessel, Electric Resistance Tomography