Giebler, E.:

51. Meeting of the International Society of Electrochemestry (ISE) 2000, Warschau 09/00

The contribution deals with the representation of electrochemical engineering knowledge by models and the application of models for computer simulation. An oxidation cell for recovering peroxodisulfate is used as an example to clarify the shown concepts. The modelling of electrochemical processes is the basis of process design and of control design. During process operation models can support production planing and production monitoring. Some important quantities for the representation of electrochemical processes are volume, volume flow, material flow, concentration, current or current density, voltage and reaction rate. Models which are restricted to volume respectively volume flow and concentration are in many cases sufficient to describe the technical relevant electrochemical processes. Material balance equations and volume equations are the basis of these models. It will be presented a general electrochemical processes model. Specifying this general model it is possible to generate a model library which cover a wide range of practical relevant electrochemical process units. The determination of the reaction rate dependencies is the most difficult part in the modelling process since a theoretic based derivation often fails because of the complexity of many electrochemical reactions. Experimentally based modelling is the opposite way to get a reaction model but the experiments normally require considerable effort. Therefore a combination of these two approaches is an alternative for obtaining models of non simple processes. An oxidation cell for recovering of peroxodisulfate shall serve as example for the derivation of a special model from the general model. The current efficiency determine the rate of the current driven chemical reactions. A black box model describes the relation between volume flow, current and produced peroxodisulfate for steady-state whereas a differential equation based model which uses explicit current efficiency functions characterises the dynamics of the outlet concentration.