Nonlinear dynamics and control of a recycle fixed bed reactor

Recke, Bodil; Jørgensen, Sten Bay

doi:10.1109/acc.1997.608940

Cited by 6 publications

(6 citation statements)

References 13 publications

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“…The reaction system is described by a series of first order, nonlinear, hyperbolic partial differential equations of the form shown in eq 5. Previous work in the control of nonlinear hyperbolic distributed parameter systems considered modal approximation, the method of characteristics, − and geometric control approaches in which the controlled variables and possibly the manipulated variables are distributed in space.…”

Section: Model-based Controlmentioning

confidence: 99%

Hydrothermal Treatment of C−N−O−H Wastes: Model-Based Reactor Effluent Control

and¹,

Littell²,

Dell`Orco³

et al. 2001

Ind. Eng. Chem. Res.

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In this work, we present model-based control and estimation algorithms developed to control the effluent composition for a hydrothermal oxidation reactor. The reactor is used to oxidize the organic compounds present in the hydrolysate solutions obtained from the destruction of HMXbased high explosives by base hydrolysis. The objective of the model-based control is to minimize the total amount of aqueous nitrogen compounds in the effluent of the reactor while maintaining the desired excess oxygen concentration in the reactor to ensure the complete destruction of the organic carbon compounds. A novel aspect of the controller design for this reactor is that the total aqueous nitrogen effluent concentration is locally uncontrollable at the desired optimal operating conditions. The controller uses a plug-flow reactor model with a reduced kinetic model describing the oxidation-reduction reactions in the hydrothermal oxidation reactor. Simulation and reactor implementation results are used to verify the closed-loop control algorithm.

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Section: Model-based Controlmentioning

confidence: 99%

Hydrothermal Treatment of C−N−O−H Wastes: Model-Based Reactor Effluent Control

and¹,

Littell²,

Dell`Orco³

et al. 2001

Ind. Eng. Chem. Res.

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“…In fact, process with recycle becomes unclear at present. Few efforts has been recently devoted to understand this dynamics and control of such kind of process (see [10] and references therein; also [11][12][13][14][15]). Luyben [10] showed that a recycle system requires a large time constant (related to residence time) because as recycling-rate increases as instability can be induced.…”

Section: Introductionmentioning

confidence: 99%

Temperature control via robust compensation of heat generation: Isoparaffin/olefin alkylation

Carrizales-Martínez

Femat

González‐Álvarez

2006

Chemical Engineering Journal

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The temperature control of the heterogeneous alkylation, where H 2 SO 4 is used as catalyst, is discussed in this paper. The problem is to design a control function to stabilize temperature in face of uncertain kinetic model. The proposed controller, whose structure resembles a PI-controller, is based on energy balance. The resulting feedback controller is robust, leads to an acceptable performance, and computes the temperature of the coolant from the refrigeration section to the reactor. The effectiveness and robustness of the designed controller for computing the coolant temperature is tested by means of simulations in such a manner that we study the effects of: (i) load disturbances, (ii) model uncertainties and (iii) initial conditions for estimation values.

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“…Some of the earlier nonlinear studies have considered a stand-alone reactor, while the effect of recycling a fraction of the reactor effluent have been occasionally addressed. , Some other authors have examined systems where only mass or heat integration was considered, but not both . Thus, three main lines of thinking can be found in the literature for solving the problem of integrated (heat/mass) plants, namely, (i) processing from a control perspective, (ii) heuristic-based methodologies, and (iii) optimization-based methodologies.…”

Section: Introductionmentioning

confidence: 99%

“…1,2 Some other authors have examined systems where only mass or heat integration was considered, 3 but not both. 2 Thus, three main lines of thinking can be found in the literature for solving the problem of integrated (heat/mass) plants, namely, (i) processing from a control perspective, (ii) heuristic-based methodologies, and (iii) optimization-based methodologies. (Comprehensive revisions can also be found in the work of Wu and Yu 14 and Seferlis.…”

Section: Introductionmentioning

confidence: 99%

Methodology for the Design and Analysis of Reaction−Separation Systems with Recycle. 1. The Design Perspective

Ramírez

Gani

2007

Ind. Eng. Chem. Res.

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A three-stage systematic model-based analysis methodology for the integrated design-control for chemical process with a reaction-separation with recycle scheme is presented. At the core of the methodology, a model-based analysis of first-principles models of different complexities identifies the important interactions between the design and process variables, so that specified design targets may be achieved. Stage 1 in the model-based methodology simplifies the design-control problem, such that the main operations are identified. The corresponding model, which has been developed in terms of dimensionless variables, helps to identify the limiting values of a set of lumped (design process) variables and locates operational windows where process feasibility can be assessed. In stage 2, more-detailed models are developed by delumping the set of lumped variables and relaxing the assumptions of stage 1. The only solutions to be considered are those lying within the bounds (operation windows) defined in stage 1. The objective of stage 2 is to identify the location of an optimal operation based on a specified design target. Stage 3 is used as a verification stage, by means of more-rigorous models in steady-state and dynamic models. Through the solution of a hierarchical subproblems, the solution of a complex design-control problem is therefore obtained systematically, along with an understanding of the process behavior. The ethylbenzene production process is used to highlight the design features of the methodology.

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Nonlinear dynamics and control of a recycle fixed bed reactor

Cited by 6 publications

References 13 publications

Hydrothermal Treatment of C−N−O−H Wastes: Model-Based Reactor Effluent Control

Hydrothermal Treatment of C−N−O−H Wastes: Model-Based Reactor Effluent Control

Temperature control via robust compensation of heat generation: Isoparaffin/olefin alkylation

Methodology for the Design and Analysis of Reaction−Separation Systems with Recycle. 1. The Design Perspective

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