Integrated Design of Effluent Treatment Systems

Walsh, Stephen; Perkins, John D.

doi:10.1016/s1474-6670(17)54018-5

Cited by 9 publications

(16 citation statements)

References 3 publications

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“…3) (rd/kd) + 0d. This is then an upper bound on the allowed delay in the process (Walsh, 1993). This is the same value as was obtained in equation (14) using the frequency domain in the case of feedforward control.…”

Section: Step Response Controllability Analysismentioning

confidence: 67%

“…Recall that the expression for dia in (26) compares very well with the numerical closed-loop step responses using PI control (Walsh, 1993). Thus, by comparing 6a in (26) and (28) we see that the open-loop step response analysis is optimistic by a factor n!.…”

Section: Remarksmentioning

confidence: 68%

“…This example was motivated by the thesis of Walsh (1993), who analyzed controllability of waste water systems using an open-loop step response analysis. Walsh compared numrically (p. 150) estimates of the achievable control using an open-loop step response analysis, with the actual closed-loop step responses using PI control on each tank.…”

Section: Remarksmentioning

confidence: 99%

“…It is instructive to study in more detail the difference between a step response and frequency domain controllability analysis for the case with n tanks in series. Let us follow Walsh (1993) and use the "disturbance attenuation" as a basis of comparison. Let d denote the concentration disturbance entering the first tank (after mixing the two feed streams), and let y denote the concentration in the last tank.…”

Section: Remarksmentioning

confidence: 99%

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A procedure for SISO controllability analysis—With application to design of pH neutralization processes

Skogestad

1996

Computers & Chemical Engineering

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Abstract--A procedure for analyzing the input-output controllability of single-input single-output (SISO) systems is presented. This procedure is applied to a pH neutralization process which must be redesigned to get acceptable controllability. It is found that more or less heuristic design rules given in the literature follow directly. The key steps in the analysis are to consider disturbances and to scale the variables properly. It is suggested that most of the material presented in this paper is suitable for an undergraduate control course.

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Section: Step Response Controllability Analysismentioning

confidence: 67%

Section: Remarksmentioning

confidence: 68%

Section: Remarksmentioning

confidence: 99%

Section: Remarksmentioning

confidence: 99%

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A procedure for SISO controllability analysis—With application to design of pH neutralization processes

Skogestad

1996

Computers & Chemical Engineering

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“…Another advantage with multiple stages is that one may use successively smaller and smaller control valves, leading to a more precise manipulable variable in the last stage. McMillan and Shinskey both recommend different sized tanks to avoid equal resonance frequencies in the tanks, but this has later been questioned (Walsh, 1993;Faanes and Skogestad, 2000;Faanes and Skogestad, 2003).…”

Section: Introductionmentioning

confidence: 99%

Controller design for serial processes

Faanes

Skogestad

2005

Journal of Process Control

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Conceptually, a multivariable controller uses the two basic principles of "Feedforward" action, based mainly on the model (for example the off-diagonal decoupling elements of the controllers), and feedback correction, based mainly on the measurements. The basic differences between feedback and feedforward control are well-known, and these differences also manifest themselves in the multivariable controller.Feedforward control may improve the performace significantly, but is sensitive to uncertainty, especially at low frequencies. Feedback control is very effective at lower frequencies where high feedback gains are allowed.In this paper we aim at obtaining insight into how a multivariable feedback controller works, with special attention to serial processes. Serial processes are important in the process industry, and the structure of this process makes it simple to classify the different elements of the multivariable controller.An example of neutralization of an acid in a series of three tanks is used to illustrate some of the ideas.

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Reductive Elimination of ArCF₃ from Bidentate Pd^II Complexes: A Computational Study

Anstaett

Schoenebeck

2011

Chemistry A European J

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The reductive eliminations of ArCF(3) from Pd(II) complexes bearing small- and large-bite-angle phosphane ligands have been investigated using computational methods. QM/QM' and QM/MM studies were applied and complemented with CP2K molecular dynamics investigations. The ligand substituents were varied and a decomposition analysis was performed to allow us to gain insights into the steric and electronic properties of the ligands. The greater reactivity of Xantphos-derived (Xantphos=4,5-bis(diphenylphosphino)-9,9-dimethylxanthene) complexes in the reductive elimination of ArCF(3) is primarily due to the lower repulsive effect of the phoshine substituents in the transition state than in the reactant complex, combined with the increased electronic interaction in the transition state. For DPPE (1,2-bis(diphenylphosphino)ethane), the steric effect of the ligand substituents is greater in the transition state, leading to a higher reaction barrier overall for reductive elimination. There is no direct correlation of the reactivity with the bite angle of the reactant complexes. Only for complexes with large ligand substituents may the bite angle of the Pd complexes be used as a guide for reactivity.

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Integrated Design of Effluent Treatment Systems

Cited by 9 publications

References 3 publications

A procedure for SISO controllability analysis—With application to design of pH neutralization processes

A procedure for SISO controllability analysis—With application to design of pH neutralization processes

Controller design for serial processes

Reductive Elimination of ArCF₃ from Bidentate Pd^II Complexes: A Computational Study

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Integrated Design of Effluent Treatment Systems

Cited by 9 publications

References 3 publications

A procedure for SISO controllability analysis—With application to design of pH neutralization processes

A procedure for SISO controllability analysis—With application to design of pH neutralization processes

Controller design for serial processes

Reductive Elimination of ArCF3 from Bidentate PdII Complexes: A Computational Study

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Reductive Elimination of ArCF₃ from Bidentate Pd^II Complexes: A Computational Study