Beschreibung
The goal of this work is to address the challenge of developing and implementing online optimizing control schemes for the time optimal operation of semi-batch polymerizations. Two semi-batch polymerization reactors are used as case studies to evaluate the advanced control solutions that are proposed. The first reactor belongs to the company Evonik Industries AG and is located in Marl (Germany). The second reactor is the well-known Chylla-Haase Reactor, which is widely accepted as a benchmark problem for the temperature control of polymerization reactors. Different optimizing schemes of different complexities that simultaneously optimize the cooling power and the monomer dosage online during the process operation are proposed and thoroughly tested. Crucial factors for a successful industrial implementation like the development of a reliable process model and the online compensation of model uncertainties are discussed in detail. A novel approach for the online compensation of the model uncertainties is proposed and a full nonlinear model predictive controller (NMPC) for the time optimal operation of semi-batch polymerizations is introduced. Moreover, a simplified optimizing control scheme that tracks operation conditions near to optimality in a feedback fashion is also proposed and implemented at the industrial process providing very good results. The effectiveness of the control schemes is illustrated by simulations and results taken from the application at the real plant.
