On‐Line runaway detection in batch reactors using chaos theory techniques

Strozzi, Fernanda; Zaldı́var, J.M.; Kronberg, Alexandre E.; Westerterp, K.R.

doi:10.1002/aic.690451116

Cited by 97 publications

(90 citation statements)

References 42 publications

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“…In this sense, if we are in a dangerous situation when div>0 [5] and we are in a safe situation when div<0, it seems natural to conclude that if we want to maximise production (reducing time between batches) and work on safety conditions we should impose div = 0 as our controller set-point. However, for dissipative systems like BR, the state space volume .…”

Section: The Time-step Volume Preserving Control Approachmentioning

confidence: 99%

“…The results show that the reconstructed divergence can be used for control and optimization of chemical reactors. In addition, by maintaining div 0 we are avoiding dangerous conditions as described above [5]. The next step of this research will be the real implementation of this control strategy on an experimental reactor and the testing of their robustness against noise and operator manipulations that occur in real plants.…”

Section: Introductionmentioning

confidence: 99%

“…As the divergence of the system can be obtained from temperature measurements using state space reconstruction techniques [5,12], we have developed in this work several control strategies and tested their application on-line using, not the analytical values of the divergence as in [14], but its reconstructed values from temperature measurements. The results show that the reconstructed divergence can be used for control and optimization of chemical reactors.…”

Section: Introductionmentioning

confidence: 99%

“…In this case, the reactor works close to batch conditions. In a series of previous works [5][6][7][8], a new criterion to delimit runaway boundaries was developed applying techniques from nonlinear dynamical systems theory to characterize the sensitivity of chemical reactors. The runaway detection criterion was defined as when the divergence of the reactor becomes positive on a segment of the reaction path, i.e.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Time-Step Volume-Preserving Control of Chemical Reactors

Comenges¹,

Strozzi²

2007

TOCENGJ

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Section: The Time-step Volume Preserving Control Approachmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Time-Step Volume-Preserving Control of Chemical Reactors

Comenges¹,

Strozzi²

2007

TOCENGJ

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“…and, taking the first term of the Taylor expansion of the logarithm, the divergence of a dynamic system can be calculated using the state space volume, V t , (Strozzi et al, 1999):…”

Section: State Space Divergence Reconstruction Using Experimental Datamentioning

confidence: 99%

Divergence control of a one-level supply chain replenishment rule

Strozzi¹,

Noè²,

Zaldı́var³

2012

International Journal of Production Research

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Divergence as a goal function for control and on‐line optimization

2005

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in Wiley InterScience (www.interscience.wiley.com).The control and optimization of batch reactors is an active field of research due to the complexity and number of processes that are carried out in these reactors, the strong nonlinearities present in the process, the fact that only few measurements -mainly temperatures-are available in real time, and the safety issues, that is, loss of temperature control leading to a runaway. A considerable amount of techniques have been presented in literature for control and on-line optimization. For a recent review on batch control the reader is refereed to Friederich and Perne (1995) and references therein, whereas for on line -optimization see Muske et al. (2004) andEloy Sequeira et al., (2004).In a series of recent works (Zaldívar et al., 2003;Bosch et al., 2004a) a new criterion to delimit runaway boundaries was developed, applying techniques from nonlinear dynamical systems theory to characterize the sensitivity of chemical reactors. The runaway detection criterion was defined as when the divergence of the reactor becomes positive on a segment of the reaction path, that is, divϾ0. Furthermore, it was shown that the divergence could be calculated on-line by measuring reactor and jacket temperatures for isoperibolic batch experiments carried out in a 240 L pilot plant reactor (Bosch et al., 2004b).In this work, we propose the use of the divergence of the system for developing a goal function for control and on-line optimization of chemical reactors. We define as optimum conditions for the operation of batch reactors as those that give div ϭ 0 at any given instant. Therefore, the control system instead of considering the difference between the set point and reactor temperatures, (T sp ϪT r ) when working on isothermal mode or set point and jacket temperature (T sp ϪT j ), when working on isoperibolic mode, it considers the divergence (0Ϫdiv) as goal function.The results for batch simulated experiments show that this control strategy is able to maintain safe conditions in case where traditional control systems will lead to a runaway, and increase the reaction rate for operating conditions where the batch production time would be too long due to the selection of conservative operating conditions. Furthermore, this approach can be easily extended to SBRs, CSTRs, and to more complex kinetic schemes, for example, parallel, consecutive, polymerizations, and so on, since the divergence has proved to be a reliable criterion of runaway conditions in all these cases (Zaldívar et al., 2003). However, further studies are necessary to compare the results with more conventional techniques aiming at maximize selectivity. Finally, the same approach for SBRs and CSTRs may be applied for controlling the dosing speed instead or in parallel to temperature control. Batch Reactors Case StudyIn order to discuss this new approach to control and on-line optimization of process plants lets use the simulated temperature data obtained for an isothermal batch reactor in which a nth-order reaction tak...

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On‐Line runaway detection in batch reactors using chaos theory techniques

Abstract: In this work nonlinear time-series analysis using delay

Cited by 97 publications

References 42 publications

Time-Step Volume-Preserving Control of Chemical Reactors

Time-Step Volume-Preserving Control of Chemical Reactors

Divergence control of a one-level supply chain replenishment rule

Divergence as a goal function for control and on‐line optimization

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