On Modeling Accuracy for Multivariable Distillation Control†

Hammarström, Leif; Waller, Kurt V.; Fagervik, Kaj

doi:10.1080/00986448208956330

Cited by 11 publications

(10 citation statements)

References 4 publications

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“…Noninteraction may or may not correlate with control quality. In a previous paper (Hammarstrom et al, 1982) it was found, for the TOFA system, that the control quality obtained by LQ design was superior to that obtained by decoupling. A comparison of the results obtained in this paper for the WOBE system with those obtained for WOBE in Hammarstrom et al (1982) by use of LQ design shows that also in this case the LQ approach leads to a better control quality, although the difference is not large for this system.…”

Section: Decoupling Versus Holistic Multiuariable Control Methods?mentioning

confidence: 94%

“…4. TOFA, a simulation model for a 10-plate column, previously studied by Toijala andFagervik (1972), Fagervik et al (1981) and Hammarstrom et al (1982). The column has a relative gain A = 3.9.…”

Section: Systems Studiedmentioning

confidence: 99%

“…In previous studies, Toijala and Fagervik (1972) and Fagervik et al (1981Fagervik et al ( ) (1983, the design has been performed by simulation of time responses in a trialand-error way. In this way it was possible to study only a very limited parameter area.…”

Section: Tuning O F Interacting Siso-loops By Inamentioning

confidence: 99%

“…There have recently been several voices raised in favor of 1-way decoupling in distillation instead of 2-way decoupling (Shinskey, 1977, Jafarey e t al., 1978, 1980, Fagervik et al, 1981, 1983.…”

Section: -Way Decouplingmentioning

confidence: 99%

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Decoupler Design and Control System Tuning by Ina for Distillation Composition Control†

Waller

Wikman

Gustafsson

1985

Chemical Engineering Communications

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Six distillation column models have been used in studies of the usefulness of the Inverse Nyquist Array (INA) method for design of dual composition control for distillation. Five of the column models are experimental, one describing an industrial column, the others four pilot plants. One column model is obtained by modeling from first principles.The control strategies investigated and compared are multiloop SISO, 2-way decoupling and I-way decoupling. The control variables are the standard ones, i.e. reflux flow and boilup.In most of the cases INA has been found to be a useful tool for design of the loops and for comparison of the different control approaches. INA has also been found to be useful for simultaneous tuning of the decouplers and the feedback controllers.For 2-way decoupling the criterion to minimize interaction at the critical frequency for each primary feedback loop has been found useful in most, but not all, cases. The scheme can be designed by pure gains in the decouplers and there is no reason to introduce dynamics into the decouplers-the systems studied are already sufficiently rich in dynamics.INA has been found to be a suitable vehicle for the choice between the two possible I-way decou~line schemes. . -With the design approach taken, 1-way decoupling has been found to provide considerably better control quality than 2-way decoupling in two of the six systems, the differences in control quality being small in the other cases.The effect of model mismatching on the results, caused e.g. by process nonlinearities, is discussed and simple rules to decrease the parameter sensitivity for 2-way decoupling schemes are given. When model mismatching is considered, the advantage of 1-way decoupling over 2-way decoupling seems to increase.One deficiency of the INA design as used in this paper is that it does not single out the design which is to be preferred on the grounds of robustness.

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Section: Decoupling Versus Holistic Multiuariable Control Methods?mentioning

confidence: 94%

Section: Systems Studiedmentioning

confidence: 99%

Section: Tuning O F Interacting Siso-loops By Inamentioning

confidence: 99%

Section: -Way Decouplingmentioning

confidence: 99%

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Decoupler Design and Control System Tuning by Ina for Distillation Composition Control†

Waller

Wikman

Gustafsson

1985

Chemical Engineering Communications

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“…Thus, there is a need for experimental investigations where various modeling assumptions used in simulation studies are tested. It is, for example, possible that assumptions usable for one strategy (such as single-loop control) turn out to be too crude for another strategy (e.g., true multivariable control; cf., Hammarstróm et al (1982)).…”

mentioning

confidence: 99%

An experimental comparison of four control structures for two-point control of distillation

Waller¹,

Finnerman²,

Sandelin³

et al. 1988

Ind. Eng. Chem. Res.

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The Dubinin-Astakhov equation, which is based on the micropore volume filling theory, is extended to mixed-gas adsorption by using the concept of maximum available pore volume. The proposed model requires only single-gas data for predicting mixed-gas adsorption; no additional equation, such as the Lewis relationship, is needed. The proposed model is not iterative, and the calculation involved is extremely simple. The model has been tested against experimental data for 16 binary

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