Batch-to-batch control of characteristic points on the PSD in experimental emulsion polymerization



An integrated batch-to-batch and in-batch control algorithm to regulate the endpoint particle size distribution (PSD) in an experimental semibatch emulsion copolymerization reactor is presented. Partial least squares (PLS) models of the process are utilized in a model predictive control (MPC) framework to regulate the PSD. The high dimensionality of the PSD is reduced through the use of a new approach, where the heights and positions of the characteristic points on the distribution are used to represent the whole distribution. This approach enables one to shift control priorities on the positions of the modes of a distribution with respect to the heights of the modes as well as efficiently reducing the dimensionality of the problem. The proposed algorithm is first tested on the simulation of the plant and showed success in regulating the PSD both in set point changes and against persistent disturbances. The experimental validation of the algorithm included two case studies where the controller was found to be effective. © 2008 American Institute of Chemical Engineers AIChE J, 2008