Packed bed reactors are used for chemical processes involving solid state catalysts and liquid or gaseous fluids. The catalysts - commonly used are spheres, cylinders or other geometric shapes - are rigidly packed inside a tube. Then, the fluid reactant flows alongside the catalysts and the reactions take place on their surfaces.

User-defined objects might be of special interest in many application areas and not only when creating new shapes for catalysts. These are all objects that go beyond the standard geometric shapes by combining or intersecting them. Once they are created, they can be used in GeoDict in many different ways and in the same way as the object shapes that are predefined in the GUI of the generator modules.

The settings for the generation of reactor and catalysts, as well as for the flow simulation, have been inspired by the settings presented in Dorai et al. (2015).