Compartment model structure identification with qualitative methods for a stirred vessel

Egedy, Attila; Varga, Tamás; Chován, Tibor

doi:10.1080/13873954.2012.700939

Cited by 7 publications

(5 citation statements)

References 18 publications

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“…The liquid column in the reactor can be assumed with a plug-flow behavior but is in transient conditions as the concentration changes both along the time and along the axial direction. For modeling purposes, the reactor can be schematized as a series of well mixed cells or liquid portions distributed along the liquid column, according to the well-known compartmental models (Egedy et al, 2013;Haag et al, 2018). In the scheme reported in Figure 4 the cells scheme related to ELR configuration is reported.…”

Section: Description Of the Reactors And The Related Mathematical Modelmentioning

confidence: 99%

The Evolution of the Fed Batch Ethoxylation Reactors to Produce the Non-Ionic Surfactants

et al. 2021

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The most recent reactor technology to produce non-ionic surfactants via ethoxylation reaction is illustrated in the present work. The most advanced reactors are deeply illustrated for what concerns the working principle and the main performance. In detail, Venturi Loop Reactor (VLR), Spray Tower Loop Reactor (STLR) and Enhanced Loop Reactor (ELR) are depicted, and the related performance compared. ELR shows the highest flexibility, to reach the desired ethoxylation degree, and at the same time good performances comparable with the VLR. Moreover, ELR allows to reach high ethoxylation degree, as in this condition, a good mixing, in the case of high liquid expansion, is difficult to be achieved with the other reactors. Thus, it is possible to work at higher ethoxylation degree respecting safety issues. Finally, a comprehensive model was proposed to describe quantitatively the mentioned reactors. The model is characterized by a general validity and can be easily adapted to each specific reactor configuration.

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Section: Description Of the Reactors And The Related Mathematical Modelmentioning

confidence: 99%

The Evolution of the Fed Batch Ethoxylation Reactors to Produce the Non-Ionic Surfactants

et al. 2021

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“…These are compartments which are assumed to be perfectly stirred and homogeneous (Continuous Stirred Tank Reactor (CSTR) model) or compartments exhibiting turbulent plug flow (Plug Flow Reactor (PFR) model). These compartments are linked through mixer (M) and distributor (D) models [13]. These latter units are usually only of mathematical significance and their volume is assumed to be zero.…”

Section: Introductionmentioning

confidence: 99%

“…Egedy et al [13] used a qualitative approach to identify the structures of compartments in various systems. Their developed algorithm utilized qualitative indicators of the RTD function in an identification algorithm to propose and filter out various CM structures based on their fitness.…”

Section: Introductionmentioning

confidence: 99%

Development of Compartment Models for Diagnostic Purposes

Tarcsay¹,

Bárkányi²,

Chován³

et al. 2021

Hung. J. Ind. Chem.

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The importance of recognizing the presence of process faults and resolving these faults is continuously increasing parallel to the development of industrial processes. Fault detection methods which are both robust and sensitive help to recognize the presence of faults in time to avoid malfunctions, financial loss, environmental damage or loss of human life. In the literature, the use of various model-based fault detection methods has gained a considerable degree of popularity. Methods usually based on black-box models, data-based techniques or models using symbolic logic, e.g.\ expert systems, have become widespread. White-box models, on the other hand, have been applied less despite their considerable robustness because of multiple reasons. Firstly, their complexity and the relatively vast amount of technological and modelling knowledge needed to construct them for industrial systems. Secondly, their large computational demand which makes them less suitable for online fault detection. In this study, the aim was to resolve these problems by developing a method to simplify the complex Computational Fluid Dynamics models employed to describe the equipment used in the chemical industry into less complex model structures. These simpler structures are Compartment Models, a type of white-box model which breaks down a complex system into smaller units with idealized behaviour. In the case of a small number of compartments, the computational load of such models is not significant, therefore, they can be employed for the purposes of online fault detection while providing an accurate representation of the system. For the purpose of identifying the compartmental structure, fuzzy logic was employed to create a model which approximates the real behaviour of the system as accurately as possible. Our future objective is to explore the possibility of combining this model with various diagnostic methods (expert systems, Bayesian networks, parity relations, etc.) and derive robust tools for the purpose of fault detection.

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“…x y p,q , p,q , ij td (15) The symbols I, R • , M j , and X denote the initiator, the primary initiator radicals, the monomers (j = 1, 2) and the chain transfer agent, respectively. R x,y i and D x,y denote the corresponding "live" and "dead" polymer chains with degrees of polymerization x and y with respect to the two monomers (1 and 2).…”

Section: ■ Introductionmentioning

confidence: 99%

“…A great number of segregated mixing and multicompartment models have been proposed in the literature − to address the issues associated with nonhomogeneous mixing conditions in industrial-scale reactors. Baldyga et al developed a multizone modeling approach to describe the nonhomogeneous mixing conditions in a stirred crystallizer and determined the effects of several operating parameters (i.e., addition feed rates, mixing intensity, compartment volume ratios) on the crystal size distribution.…”

Section: Introductionmentioning

confidence: 99%

Nonhomogeneous Mixing Population Balance Model for the Prediction of Particle Size Distribution in Large Scale Emulsion Polymerization Reactors

Alexopoulos

Pladis

Kiparissides

2013

Ind. Eng. Chem. Res.

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The present study describes the development of a nonhomogeneous two-compartment model for the prediction of particle size distribution in a semibatch emulsion ter-polymerization reactor. The multicompartment model accounts for spatial variations of particle size distribution (PSD) in the reactor due to nonideal mixing conditions. A comprehensive emulsion polymerization model is applied to each compartment, which allows the calculation of the various species concentrations in the aqueous and particle phases in each compartment. Moreover, a particle population balance equation is solved for each compartment to determine the individual PSDs as well as the overall PSD in the reactor. The effects of the two-compartment nonhomogeneous model parameters, that is, the volume ratio of the two compartments, the compartment exchange flow rates, and the partitioning of the monomer and initiator feed streams into the two compartments, on the overall polymerization rate and PSD are analyzed in detail. It is shown that depending on the selected values of the two-compartment model parameters, the overall PSD in the reactor can significantly vary (i.e., from a narrow and/or broad unimodal distribution to a bi- and/or multimodal PSD). Small compartment exchange flow rates, uneven monomer and initiator feed partitioning, or unequal compartment volumes can result in very different PSDs in the two compartments. Moreover, it is shown that for a range of parameter values in the two-compartment model (i.e., reflecting the degree of reactor nonhomogeneity), the calculated overall PSD in the industrial-scale reactor can be unimodal but significantly broader than the respective PSD calculated by the homogeneous one-compartment model.

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Compartment model structure identification with qualitative methods for a stirred vessel

Cited by 7 publications

References 18 publications

The Evolution of the Fed Batch Ethoxylation Reactors to Produce the Non-Ionic Surfactants

The Evolution of the Fed Batch Ethoxylation Reactors to Produce the Non-Ionic Surfactants

Development of Compartment Models for Diagnostic Purposes

Nonhomogeneous Mixing Population Balance Model for the Prediction of Particle Size Distribution in Large Scale Emulsion Polymerization Reactors

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