Control of polymer molecular weight using near infrared spectroscopy

• Published in: AIChE journal Vol. 50; no. 3; pp. 654 - 664
• Main Authors: Othman, Nida Sheibat, Févotte, Gilles, Peycelon, Dominique, Egraz, Jean-Bernard, Suau, Jean-Marc
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-03-2004; Wiley Subscription Services; American Institute of Chemical Engineers; Wiley
• Subjects: Applied sciences; Automatic Control Engineering; Chemical and Process Engineering; Chemical engineering; Chemical Sciences; Computer Science; control; Engineering Sciences; Exact sciences and technology; Infrared radiation; Molecular weight; near infrared; online estimation; Organic polymers; Physicochemistry of polymers; polymer properties; Polymerization; Polymers; Preparation, kinetics, thermodynamics, mechanism and catalysts; process control; Reactors; Spectrum analysis; Near infrared spectrometry; Polymer solutions; Polymerization reactor; Calibration; Molecular mass; Modeling; Partial least squares
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.10059

Near Infrared spectroscopy is used to control a polymerization reactor in order to produce solution polymers with well‐defined molecular weight. A model for the monitoring of both the average polymer molecular weight, and the concentration of monomer in the reactor is developed with the partial least‐squares calibration technique applied to the NIR spectra.On the basis of a process model, a nonlinear input–output linearizing geometric approach is then applied to control the polymer molecular weight by manipulating the inlet flow rate of the monomer. The control strategy is then validated on‐line during the solution polymerization of acrylic acid in an industrial pilot scale reactor. © 2004 American Institute of Chemical Engineers AIChE J, 50:654–664, 2004