Evaluation of mass transfer resistances during membrane extraction of multicomponent mixtures

In multicomponent membrane extraction each of the constituent mechanisms is defined by an appropriate matrix of mass transfer coefficients. The method to assess the relative importance of the individual mass transport resista nces has been proposed. This method is based on the calculation of norms of mass transfer matrices and is used to evaluate the relative importance of the individual transport mechanisms in multicomponent extraction studied ex perimentally by A. Kubaczka, A. Burghal dt, T. Mokrosz, Chem. Eng. Sci. 53 (1998) 899. If resistances to mass transfer identified by the method as ins ignificant, are omitted from the simulations, the agreement between numeric al predictions and experiment is not impaired. It is also demonstrated that even when the membrane resistance can be neglected (as was the case in our study), the membrane determines the ratio of mass fluxes in the stationary system of coordinates by defining the coefficients or the bootstrap (trans formation) matrix. The analysis reveals that the omission of this effect le ads to a visible drop in the accuracy of calculations of mass fluxes in mem brane extractors. (C) 2001 Elsevier Science B.V. All rights reserved.