Approach to the Theory of Separating Columns with Successive Exchange between three Fluids

Abstract

COHEN’S method has been used to develop the theory of cotinuous separating columns with successive exchange between three fluids. The equations of the column have been solved for stationary state and small concentrations. The general solutions representing the dependence of the mole fractions of the desired isotope in the three fluids on the column height involve the following particular cases: concurrent and countercurrent exchange between two fluids and two limiting cases of exchange between three fluids in which the intermediate fluid is at isotopic equilibrium with one of the other two fluids. As a general feature of the columns with successive exchange between three fluids it has been found that the ratio of the driving forces corresponding to the fluid pairs between which the mass-transfer takes place has a constant value along the column, excepting a zone situated at the bottom. Methods to calculate the rate constants from experimental data are given.