Both steady-state and dynamic models for the commercial bulk polypropylene process of HYPOL technology were developed by using fundamental chemical engineering principles and advanced software tools, Polymers Plus and Aspen Dynamics. The models consider the important issues of physical property and thermodynamic model selections, catalyst characterization, and reactor model, in addition to the traditional Ziegler-Natta polymerization kinetics. The performance of equilibrium-stage modeling was examined using the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state and a pre-built reactor model in Polymers Plus. The detection of non-equilibrium behavior for the liquid-phase reactor leads to a novel reactor model suggested in this work, wherein the vapor-liquid equilibrium behavior was separated from polymerization behavior. Besides, the traditional Ziegler-Natta polymerization system was incorporated from single-site to multi-site model by fitting the actual data sourced from open reports and certain plant data. Furthermore, we validated the models using the plant data and demonstrated the application of our dynamic model by simulating a grade change. (C) 2009 Elsevier B.V. All rights reserved.