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Distillation columns with sharp separations exhibit severely nonlinear behavior, which has been known to cause difficulties in column control and design. Such a column is characterized by sharp composition and temperature variations in the column. Previously, the binary distillation case was thoroughly analyzed using a nonlinear wave theory and such an analysis was experimentally validated. For multicomponent distillation, the complicated nonlinear dynamics of the movement and interference of multiple sharp composition variations can be elucidated with a coherent-wave theory developed earlier for general countercurrent separation processes. With a ternary alcohol mixture, the present study has experimentally verified the theory by demonstrating the existence and propagation of constant-pattern coherent waves in a 50-tray stripping column in response to a step disturbance of feed composition, feed flow rate, or reboiler heat supply. The study has also tested the theory's predictions of composition profile, wave velocities, and asymmetric dynamics.

Five kinetic models potentially applicable to ion exchange with ions of high selectivity, discussed in Part I of this study, are systematically applied to experimental data on chloride/sulfate forward and reverse exchange and sulfate isotopic exchange with three different types of resins (quaternary ammonium, tertiary amine, and secondary amine groups) and highly dilute solutions (< 0.006 N). Interpretation of these data shows conceivably that the system is controlled by film diffusion, with a small contribution from intraparticle diffusion in forward and isotopic exchange and especially for the resin of highest sulfate selectivity.