MASS-TRANSFER AND AXIAL-DISPERSION IN A KUHNI EXTRACTION COLUMN

Concentration profiles were determined in both phases for the system methyl isobutyl ketone (MIBK)-water-acetic acid in a Kuhni 72.45-mm-dia. extraction column of 25 stages. Mass transfer and backmixing parameters were estimated numerically from the profiles in terms of the backflow model. The results indicated that backmixing of the continuous phase was appreciable, while that of the dispersed phase was negligible. Independent values of the continuous-phase backmixing coefficient, alpha-c, were also determined by both unsteady-state and continuous tracer injection, in the former case both with and without mass transfer. The results indicated that alpha-c, is increased by mass transfer, and that the tracer values, both with and without mass transfer, are greater than those obtained from the profile data.