The integration of a chemical or biochemical reaction and a chromatographic separation in a single apparatus offers the opportunity to overcome chemical equilibrium as well as an increase in the separation efficiency. The different possibilities to design such a chromatographic reactor are discussed. Due to the complex behaviour modelling and simulation are powerful tools for process development and design. Therefore an overview over the different modelling approaches is given. Applying the example of the glucose isomerisation, the different processes based on the chromatographic simulated moving bed (SMB) reactor are compared. Different purity restrictions of the produced fructose syrup lead to different degrees of integration of reaction and separation in respect to a favourable process design.