Flowsheet modeling of processes with liquid, vapor, and solid phases is a very challenging task, since the description of granular materials is complicated by their disparity. On the other hand, the functional models of different apparatuses often contain a large set of empirical parameters which strongly depend on material properties and apparatus geometry. In this contribution the main problems related to the flowsheet simulation of solids processes are discussed and the usage of additional scales in the process description is proposed to estimate model parameters.