Dynamic modeling of product grade transitions for olefin polymerization processes

Debling, Jon A.; Han, Gang; Kuijpers, F.; Verburg, J.; Zacca, Jorge Jardim; Ray, W. Harmon

doi:10.1002/aic.690400312

Cited by 82 publications

(48 citation statements)

References 9 publications

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“…The softening temperature of polyethylene is approximately 400 K [1,5,10] and is shown by the dashed line in the bifurcation diagrams, since the reactor must be operated below this temperature; the analysis will be confined to the region below this line with simple explanation of the bifurcation diagram in general.…”

Section: Resultsmentioning

confidence: 99%

Effect of Polymer Particle Size and Inlet Gas Temperature on Industrial Fluidized Bed Polyethylene Reactors

Ghasem¹

1999

Chem. Eng. Technol.

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Static and dynamic bifurcation behaviors dominate the operation of fluidized bed catalytic reactors for the production of polyethylene (UNIPOL Process) and have important implications on the safe operating temperature and polyethylene production rate. The investigations show that the multiplicity of the steady state phenomenon covers a wide range of parameters together with the phenomenon of periodic oscillations with sharply changing amplitudes with a change of the chosen bifurcation parameter. In some cases, the periodic branches terminate through periodic limit point (PLPs), while in other cases it terminates homoclinically. A detailed parameteric investigation using two-parameter continuation diagrams for the loci of static and Hopf bifurcation points as well as one parameter bifurcation diagrams shows that it is possible to increase the productivity of the unit considerably without exceeding the constraints of the polymer melting point. Gas feed temperature, catalyst feed rate, and polymer particle size distribution are important operating parameters in polyethylene fluidized bed reactors. Gas velocity plays a significant role in keeping the fluidized bed bubbling in addition to the fact that it acts as a cooling media by removing excess heat generated from the polymerization reaction. The kinetic behavior of the catalyst and effect of reactor temperature on product properties require, in some cases, operating just below the softening point of the polymer which requires a suitable controller to avoid polymer melting.

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Section: Resultsmentioning

confidence: 99%

Effect of Polymer Particle Size and Inlet Gas Temperature on Industrial Fluidized Bed Polyethylene Reactors

Ghasem¹

1999

Chem. Eng. Technol.

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“…According to the influence of these factors on the polymer properties, a mechanism model [2] (1) The density of polymer is decided by structural parameters of the polymer chain frame. The polyethylene density mechanism model [3] can be described by…”

Section: Dynamic Predictive Model For Polyethylene Processmentioning

confidence: 99%

Multi-grade polymer properties robust estimation for industrial polyethylene process and application

Zhao

Sun

2011

2011 Chinese Control and Decision Conference (CCDC)

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Due to the lack of reliable on-line polymer property measurements, the advanced control of multi-grade polymer properties is difficult to achieve. In this article, a robust estimation method is proposed for industrial polyethylene process based on a predictive model. According to the approximation error upper bound of the predictive model, a method of design the robust filter is deduced. The application results to an industrial gas polyethylene process have verified the feasibility and effectiveness of the proposed method. With this method, multi-grade polymer properties of industrial polyethylene process can be on-line estimated and make it possible for achieving the advanced on-line product quality control.

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“…[4][5][6][7][8] The ability of the Monte Carlo technique to model the complete polymerization process or even product properties facilitates a more rigorous examination of whether the assumed kinetic mechanism and coefficients provide an adequate representation of the polymerization itself. 4 Up to now, there have been many published articles 1,2,[9][10][11][12] regarding the polymerization kinetics. However, past studies from microscale level are not common.…”

Section: Introductionmentioning

confidence: 99%

Multiple active site Monte Carlo model for heterogeneous Ziegler‐Natta propylene polymerization

Luo

Shi

Zhu

2009

J of Applied Polymer Sci

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In this study, the kinetics of propylene polymerization catalyzed with the fourth heterogeneous Ziegler-Natta catalyst is studied. More than one type of active site is present in the propylene polymerization based on an analysis of the GPC curves. A multiple active site kinetic model (MSmodel) is proposed by using Monte Carlo technique. Good agreements in the polymerization kinetics are achieved for fitting the kinetic profiles with the MSmodel. In addition, the MSmodel is used to describe the dynamic evolutions of the active sites and their effects on the propylene polymerization. The simulated results indicate that different types of active sites have different polymerization kinetics and the site type can affect the propylene polymerization kinetics.

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Dynamic modeling of product grade transitions for olefin polymerization processes

Cited by 82 publications

References 9 publications

Effect of Polymer Particle Size and Inlet Gas Temperature on Industrial Fluidized Bed Polyethylene Reactors

Effect of Polymer Particle Size and Inlet Gas Temperature on Industrial Fluidized Bed Polyethylene Reactors

Multi-grade polymer properties robust estimation for industrial polyethylene process and application

Multiple active site Monte Carlo model for heterogeneous Ziegler‐Natta propylene polymerization

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