Abstract Modern production processes in chemical, pharmaceutical and biological industries are characterized by complex process structures, which consist of different apparatuses and process steps. Modeling the entire process requires simulating all units altogether, while taking into account interconnections between them. Nevertheless, in the area of solids processing, there is nowadays an unfilled gap from the side of computer support of process modeling in allowing effective optimization and prediction of the behavior of the whole plant. This paper presents a tool for flowsheet simulation which allows the simulation of the stationary behavior of complex processes dealing with solids and its extension towards dynamic modeling. Also, a new simulation concept is proposed on the basis of the multiscale approach. On the macroscale, flowsheet simulation is performed with the help of the SolidSim system. Parameters for the macromodels in SolidSim are predicted by microscale simulation. The models for the two scales are then coupled by inter-scale communication laws. Application of the proposed modeling concept is shown by an example of fluidized bed granulation.