The parameter estimation problem and its application to industrial data obtained from polymerization processes are analyzed. The polymerization process model consists of the material balances with the polymerization kinetics for the reactor and a simplified dynamic model for the downstream separator. The estimable kinetic parameters in the process model are obtained for plant data by analyzing the associated optimization problem. Two kinetic parameters are estimable for the copolymer data and the homopolymer data based on the information in the available industrial plant data. The identified process model forms the basis for a monitoring and feedback control system for these processes.