Mass transfer enhancement in the Membrane Aromatic Recovery System (MARS): theoretical analysis

This work investigates three different models describing mass transfer enhancement by a reversible and instantaneous second-order chemical reaction. The three models are applied to the study of mass transfer phenomena occurring in a membrane process for recovery of organic chemicals, the Membrane Aromatic Recovery System (MARS). Typical MARS operating conditions are used as model inputs, and the results obtained are used to assess the degree of complexity that should be taken into account in describing the mass transfer phenomena. The most complex model derived (N-P model) accounts for chemical reaction reversibility and the Nernst-Planck effect created by ionic species and is solved numerically. Following Olander model for a second order reversible instantaneous reaction model is proposed, for which we derive an analytical solution in terms of bulk solution properties. Finally, the simplest model follows the analysis of Hatta, assuming irreversible chemical reaction and neglecting the Nernst-Planck effect. The reversibility of the reaction is shown to be important, while N-P effects are negligible. The Olander model is recommended for use in describing the mass transfer phenomena. The models developed can be applied further to other processes of similar type. (C) 2004 Elsevier Ltd. All rights reserved.