Polynomial ARMA model identification for a continuous styrene polymerization reactor using on-line measurements of polymer properties

Na, Sang-Seop; Rhee, Hyun‐Ku

doi:10.1002/(sici)1097-4628(20000624)76:13<1889::aid-app6>3.0.co;2-y

Cited by 8 publications

(2 citation statements)

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“…[109][110][111][112] to improve control performance. Fundamental models can also be used to test empirical models developed for control purposes [113].…”

Section: Model-based Controlmentioning

confidence: 99%

Free‐Radical Polymerization: Homogeneous

Hutchinson¹

2005

Handbook of Polymer Reaction Engineering

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Free-radical polymerization (FRP) is one of the most important commercial processes for preparing high molecular weight polymers. It can be applied to almost all vinyl monomers under mild reaction conditions over a wide temperature range and, although requiring the absence of oxygen, is tolerant of water. Multiple monomers can be easily copolymerized via FRP, leading to the preparation of an endless range of copolymers with properties dependent on the proportion of the incorporated comonomers. This chapter will provide an overview of the kinetics and mechanisms, and the techniques used to construct mathematical representations of bulk and solution FRP. The description will also serve as a good base for the suspension and emulsion FRP chapters that follow. FRP Properties and ApplicationsPolymers produced via free-radical chemistry include the following major families:Low-density polyethylene (LDPE) and copolymers, used primarily in films and packaging applications. LDPE has density of <0.94 g cm À3 , and is produced via high-pressure free-radical polymerization; polyethylenes of higher density (and polypropylene) are produced via transition metal catalysis, as described elsewhere (see Chapter 8). Poly(vinyl chloride) and copolymers, used primarily to produce pipe and fittings, flooring material, and films and sheet. Polystyrene and its co-and terpolymers with acrylonitrile and butadiene. Homopolymer is used for packaging and containers, while the acrylonitrile-containing polymers are used for various molded products in the appliance, electronics, and

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“…[109][110][111][112] to improve control performance. Fundamental models can also be used to test empirical models developed for control purposes [113].…”

Section: Model-based Controlmentioning

confidence: 99%

Free‐Radical Polymerization: Homogeneous

Hutchinson¹

2005

Handbook of Polymer Reaction Engineering

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“…We employ the pseudorandom multilevel input signals for data generation because these are close to the white autocorrelation function and adequately excite nonlinear modes of the MIMO system. 12, 13 For the purpose of evaluating the model accuracy, we use the variance accounted for (VAF) index, which is defined as follows:…”

Section: Wiener Model Identificationmentioning

confidence: 99%

Nonlinear Model Predictive Control Using a Wiener Model of a Continuous Methyl Methacrylate Polymerization Reactor

Jeong

Yoo

Rhee

2001

Ind. Eng. Chem. Res.

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A subspace-based identification method of the Wiener model, consisting of a state-space linear dynamic block and a polynomial static nonlinearity at the output, is used to retrieve the accurate information about the nonlinear dynamics of a polymerization reactor from the input-output data. The Wiener model may be incorporated into model predictive control (MPC) schemes in a unique way that effectively removes the nonlinearity from the control problem, preserving many of the favorable properties of the linear MPC. The control performance is evaluated by simulation studies, for which the original first-principles model for a continuous methyl methacrylate polymerization reactor takes the role of the plant while the identified Wiener model is used for control purposes. On the basis of the simulation results, it is demonstrated that, under the presence of strong nonlinearities, the Wiener model predictive controller (WMPC) performed quite satisfactorily for the control of polymer qualities in a continuous polymerization reactor. The WMPC strategy proposed is validated by conducting an online digital control experiment with an online densitometer and viscometer. It is observed that the WMPC performs satisfactorily for the polymer property control of the highly nonlinear multiple-input multiple-output system with input constraints.

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