Applications of Nonlinear Observers and Control:  Improving Productivity and Control of Free Radical Solution Copolymerization

Abstract

A nonlinear state observer that uses the rate of heat generation due to chemical reaction for the real-time evaluation of key parameters during free radical solution copolymerization is presented. These parameters include the cumulative and instantaneous copolymer compositions, the overall and individual monomer conversions, and the overall termination rate constant associated with the reaction. The information thus obtained is used to control the cumulative copolymer composition and to maintain the productivity of a semibatch reactor for the solution copolymerization of butyl acrylate (BuA) and vinyl acetate (VAc) in ethyl acetate (EAc) at its highest possible level. Both the state and parameter estimation of this observer were then used for the nonlinear control of copolymer composition and optimal reactor productivity.

Dinamička simulacija rada šaržnog polimerizacijskog reaktora i parametarska analiza homopolimerizacije stirena

“…Iz teorije slobodno-radikalskih polimerizacija poznato je da se ne mogu istodobno postići velike brzine reakcije polimerizacije te proizvesti polimeri velikih molekulskih masa i uske raspodjele masa, koji su nužni za određene primjene. [8][9][10][11][12] Stoga je u posljednjih 10-ak godina razvijeno nekoliko novih postupaka sinteze kojima je moguće kontrolirati strukturnu građu sintetiziranih polimera odnosno molekulsku masu, raspodjelu molekulskih masa (disperznost), funkcijske skupine i sastav. Među njima se posebno ističe povrativo-deaktivacijska radikalska polimerizacija (prethodno nazivana kontrolirana radikalska ili živuća radikalska polimerizacija), gdje se polimerizacija provodi s novim inicirajućim sustavima kao što su različiti katalizatori, ionski i organometalni kompleksi.…”

Design and Application of Model-on-Demand Predictive Controller to a Semibatch Copolymerization Reactor

“…The reaction temperature ( T r ) and the feed flow rate ( q f ) are taken as the manipulated variables, while the weight-average molecular weight ( M w ) and the instantaneous copolymer composition ( F 1 ) are the controlled outputs. The instantaneous composition F 1 refers to the composition of the comonomers in the copolymer chains produced at any given instant, which depends on the relative rates of the addition of monomers 1 and 2 into the polymer and is expressed as the ratio of the respective rates of propagation where R p i denotes the propagation reaction rate of monomer i and subscript 1 represents the more reactive monomer, MMA.…”

Simultaneous control of copolymer composition and MWD in emulsion copolymerization

“…Both estimators and observers (Sbenz de Buruaga et al. 1996, 1997a,b, 2000Viccntc et al, 2001;Hammouri et al, 1999;McKenna et al, 2000) have been applied to estimate unreacted amounts of monomers in solution and emulsion co/tcrpolymcrization. In this work an open-loop observer similar to that used in Sienz de Buruaga et al (1996Buruaga et al ( , lY97a,b.…”