Real-time estimation and control of particle size in semi-batch emulsion polymerization

The control of the relative particle growth of a bidisperse emulsion polymerization is investigated in an automated reactor control facility capable of online density and online particle size measurements. Final diameter ratio values are controlled by manipulating the monomer feed rate to the reactor using a control scheme comprised of a parameter adaptive Kalman filter with steady state gains and a nonlinear model predictive controller. One of the main features of the implemented controller is the connection of the prediction horizon to the criterion that the overall conversion equal 90% at the end of the batch. Feedback is incorporated into the algorithm at each sampling time by starting the model prediction calculation at the current estimated values of the model states. The controller performs well to meet a challenging diameter ratio set point at the end of the batch. The robustness of the controller to reject an induced initial initiator concentration disturbance is demonstrated