MASS-TRANSFER TO FREELY-MOVING DROPS

Mass transfer coefficient data are presented for the transfer of solut es between isolated drops and continuous phase in a droplet file colum n. Radioactivity labelled, i.e. tritiated water was used as a tracer t o obtain values of the individual phase coefficients in saturated bina ry systems. Those for the continuous phase were found to be satisfacto rily represented by the Garner-Tayeban correlation, and a new model, b ased on the introduction of inertia into that of Kronig and Brink, was developed for the dispersed phase. Data were also obtained for the tr ansfer of both bulk and C-14-labelled acetic acid between methyl isobu tyl ketone (MIBK) and water, and the resulting overall coefficients we re compared with those predicted from the individual coefficient data. Agreement was good for bulk transfer into the drops, but those for tr ansfer out of the drops were enhanced by a factor of 2-3 by Marangoni instability, as expected. A similar enhancement was also observed, sur prisingly, for tracer transfer out of MIBK drops, but not out of water drops.