Dynamic modelling of catalytic three-phase reactors for hydrogenation and oxidation processes

The dynamic modelling principles for typical catalytic three-phase reactors , batch autoclaves and fixed (trickle) beds were described. The models cons ist of balance equations for the catalyst particles as well as for the bulk phases of gas and liquid. Rate equations, transport models and mass balanc es were coupled to generalized heterogeneous models which were solved with respect to time and space with algorithms suitable for stiff differential e quations. The aspects of numerical solution strategies were discussed and t he procedure was illustrated with three case studies: hydrogenation of arom atics, hydrogenation of aldehydes and oxidation of ferrosulphate. The case studies revealed the importance of mass transfer resistance inside the cata lyst pallets as well as the dynamics of the different phases being present in the reactor. Reliable three-phase reactor simulation and scale-up should be based on dynamic heterogeneous models.