Mass and heat transfer to drops in a mixer-settler

Abstract

This paper reports an experimental study of heat and mass transfer in a mixer-settler. Transport took place from a continuous phase of highly refine kerosene to water drops dispersed therein by a pump-mix impeller. In the case of mass transfer, the water drops extracted 2-ethylbutyric acid from the organic phase. Temperatures were measured by thermistors and concentrations by chemical analysis. Fritted-glass and porous Kel-F filters were employed to selectively sample a single phase from the two-phase dispersion. Also described is a drop counter developed for determining average drop size. Experimental measurements indicated that virtually all transfer took place to drops moving through continuous organic phase of essentially uniform concentration and temperature; end effects were apparently negligible. Film coefficients for heat and mass transfer were developed from the experimental information and estimated drop lifetime and velocity. The experimental values were compared with the predictions of several theories. In general, experimental results agree better with the models based on eddy diffusion in a vibrating drop than those models which postulate a stagnant or circulating drop.