State estimation for semicontinuous emulsion copolymerization using calorimetric data

Semicontinuous emulsion copolymerization is one of the major processes in the production of polymer lattices. For optimization or control purposes it is necessary to measure important product qualities such as the composition of the copolymer or the average chain length of the macromolecules. Measurements of such properties for a multiphase process are expensive and usually not available online. State estimation is besides reaction calorimetry a possibility to overcome this problem. Starting from a complex model of the considered process we develop a simplified model which enables us to estimate the concentrations of the monomers in the particle phase and thus the composition of the copolymer using a constrained extended Kalman filter (CEKF). We show that this approach is robust to modeling errors. The CEKF is also compared to an EKF. From the results it follows that the CEKF has a better robustness to errors of the initial values