Steady-State and Dynamic Modeling of the Basell Multireactor Olefin Polymerization Process

In this work, we developed the steady-state and dynamic models for the commercial polypropylene process of Basell Spheripol technology, involving fundamental chemical engineering principles and advanced software tools, i.e., Polymers Plus and Aspen Dynamics. The models considered the important issues of physical property and thermodynamic model selection, catalyst characterization, and reactor model. Besides, a multisite catalyst with traditional Ziegler-Natta polymerization kinetics was introduced to describe the broad molecular weight distribution of the polymers produced in this polypropylene technology. Both the continuous stirred tank reactor model and the combined plug flow reactors model were proposed to simulate the reactors. Furthermore, we validated the models using industrial data and demonstrated application of the dynamic model to grade change, start up, and shut down at a certain emergent accident.