ONLINE MOLECULAR-WEIGHT DISTRIBUTION ESTIMATION AND CONTROL IN BATCH POLYMERIZATION

A molecular weight distribution (MWD) estimator for batch methyl metha crylate solution polymerization is implemented experimentally for on-l ine control and estimation of the MWD. The estimator is based on an ex tended Kalman filter and provides current estimates of the entire MWD, reaction temperature, monomer conversion, and initiator conversion. I t uses a detailed polymerization model, on-line monomer conversion mea surements, temperature measurements, and periodic, time-delayed measur ements of the MWD from an on-line size-exclusion chromatograph. The es timator is shown to perform well with several on-line MWD estimation e xperiments. Real-time feedback control of the molecular weight is pres ented by utilizing the on-line MWD information. Temperature, monomer-a ddition, and simultaneous temperature and monomer-addition control are investigated experimentally to achieve a specific constant weight-ave rage molecular weight. The on-line feedback control is effective in re jecting realistic disturbances which deteriorate molecular weight cont rol.