Generalized Solution of the Transient Backflow Model Equations for Tracer Concentration in Stagewise Liquid Extraction Columns

Abstract

A generalized solution is presented of the transient backflow model equations, for use in determining the backmixing ratio for stagewise extraction columns from pulse tracer injection data obtained over a wide range of operating conditions. Results obtained with this model agreed with those given by earlier solutions for restricted boundary conditions. The generalized solution was also used successfully to predict the tracer response for a Kühni column in which a tracer pulse was injected into the end stage and samples were withdrawn from two downstream stages. It was observed that numerical instability can occur in all solutions at short response times for low values of the backflow ratio, ..