A dynamic process model for the simulation of the separation process in countercurrent decanter centrifuges is presented. The numerical approach uses an interconnection of compartments to characterize the residence time distribution of theparticles within the centrifuge. First, the theoretical basis of the numerical approach is described. Compared to the state-of-the-art modeling of decanter centrifuges, the proposed approach allows the simulation of the temporal filling process. The short computing time results in further advantages of the dynamic process model. The so-called real-time simulation is an opportunity for a model-based control of the separation process. An exemplary simulation with the product limestone demonstrates the main features of the numerical approach.