Mathematical modelling and identification of systems, where the structure of some equations is unknown, is a difficult task. As this is usually done manually by a human expert, it is associated with terms such as experience and intuition. However, an experienced modeller will have a clear procedure to deduce a model. In a first step he or she will analyse experimental data on a qualitative level. Only those models are then tested in a quantitative identification which pass the qualitative check. In this contribution this efficient procedure is translated into methods. A tool TAM-C is Preprint submitted to Elsevier Science 3 May 2001 introduced which automatically finds structures and parameters of formal kinetics. The main part of the contribution is dedicated to the qualitative preselection of possible model candidates and the application to an industrial process.