LPT-2011-11 [BibTeX]
Matthias Johannink, Adel Mhamdi, Wolfgang Marquardt:
Towards a rigorous model of electrodialysis processes
In: E.N. Pistikopoulos; M.C. Georgiadis; A.C. Kokossis (Eds.): 21st European Symposium On Computer Aided Process Engineering - ESCAPE 21, 116-120
Abstract:
In electrodialysis (ED), ion exchange membranes are used to separate ions of opposite
charges in an electric field. Only few mechanistic models for ED are proposed in
literature, which are based on a quasi-stationary one-dimensional formulation. We
present a generalization of the frequently used set of equations to the multi-dimensional
dynamic case. The resulting set of partial-differential algebraic equations (PDAE) is
thoroughly analyzed by means of an extended index analysis. It is shown that the
introduction of the electroneutrality condition, which is frequently used in models
arising in electrochemistry, leads to a high index in time and spatial coordinates. In this
context, a reformulation to an index one PDAE system is proposed and additional
“hidden” constraints for a consistent set of initial and boundary conditions are derived.
Keywords:
electromembrane processes, electrodialysis, index analysis, electroneutrality