Applicability of Desirability Function for Control Structure Design in the Frequency Domain

Haragovics, Máté; Kencse, Hajnalka; Mizsey, Péter

doi:10.1021/ie300973b

Cited by 8 publications

(5 citation statements)

References 27 publications

(38 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is preferred that the three controllability indices are aggregated in one number. The so-called desirability function 27 , 28 is selected for such an aim. Individual desirability functions are calculated for each controllability index, and their geometric average is calculated to form the desirability function for a system using the formulas below: where a and b are 0.0004 and 0.007, respectively, and D is the aggregated desirability function for a system.…”

Section: Controllability Analysismentioning

confidence: 99%

Comparison of Controllability Features of Extractive and Pressure Swing Distillations on the Example of Tetrahydrofuran Dewatering

et al. 2021

Self Cite

View full text Add to dashboard Cite

The controllability study is an integral part of chemical process design. In this work, the controllability of two special distillation techniques, extractive distillation and pressure swing distillation, designed for the separation of azeotropic mixtures is investigated with dynamic tools. The control design interface of Aspen Plus and Matlab are applied for the modeling and evaluation of the two systems. Dynamic controllability indices are determined and aggregated in a desirability function. The results are compared to obtain efficient help for process design activity. The pressure swing distillation shows significantly better controllability features than the extractive distillation. The reason can be the fact that in the case of the extractive distillation, a third compound, the extractive agent, is added to the system to carry out the separation, therefore making the system more complex. As far as the selection of manipulated variables is concerned, in the case of the extractive distillation, the reflux flows should be preferred to the reflux ratios but in the case of the pressure swing distillation, the reboiler heat loads are preferred to the reflux ratios since those are closer to the controlled compositions. Both separation systems show worse controllability features if the product purity requirement is approaching to the pure products, that is, close to 100%. Although the energy consumption of the pressure swing distillation is higher than that of the extractive distillation, it has the inherent feature that it can be automatically heat integrated due to a column operated at high pressure and, as a consequence, higher temperatures.

show abstract

Section: Controllability Analysismentioning

confidence: 99%

Comparison of Controllability Features of Extractive and Pressure Swing Distillations on the Example of Tetrahydrofuran Dewatering

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…For each of the three controllability indices, a desirability function , is calculated. The geometric mean of the individual desirability functions gives rise to the aggregated desirability function for a particular system.…”

Section: Dynamic Control Analysismentioning

confidence: 99%

Effects of Energy Intensification of Pressure-Swing Distillation on Energy Consumption and Controllability

et al. 2022

Self Cite

View full text Add to dashboard Cite

The aim of process integration is the efficient use of energy and natural resources. However, process integration can result in a more precise process operation, that is, it influences controllability. Pressure-swing distillation processes are designed for the separation of azeotropic mixtures, but their inherent heat integration option can be utilized to significantly reduce their energy consumption. One maximum-boiling and three minimum-boiling azeotropes are considered to study and compare the nonintegrated and integrated alternatives with the tool of mathematical modeling where ASPEN Plus and MATLAB software are used. The results show that the heat-integrated alternatives result in 32–45% energy savings that are proportional to the emission reduction and the consumption of natural resources. As far as the operability is concerned, the heat-integrated alternatives show worse controllability features than the nonintegrated base case. This can be due to the loss of one controllability degree of freedom. This recommends using more sophisticated control structures for the sake of safe operation if process integration is applied.

show abstract

“…It can be successfully applied for the conventional and the thermally coupled distillation systems studied. It is important to note that this methodology that relies on frequency-dependent controllability indices is not capable of comparing different control structures of the same system − but it is capable of comparing the controllability features of different processes/systems , as it is applied for in our study.…”

Section: Case Studiesmentioning

confidence: 99%

Dynamic Controllability Comparison of Conventional Distillation Sequences and Dividing-Wall Columns with Upper and Lower Partitions Using the Desirability Function

Tarjani

Toth

Nagy

et al. 2016

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

The aim of this study is to compare the controllability properties of conventional distillation sequences and dividing-wall columns with upper and lower partitions (DWCs). The controllability analysis methodology uses the Control Design Interface (CDI) module of Aspen Dynamics to obtain the state space representation of the studied systems. The frequency dependent controllability indices are calculated by Matlab on the basis of the matrices of the transferred state space representation. The study includes the examination of the conventional direct and indirect sequences and two DWCs systematically generated from the corresponding conventional sequences. Case studies are completed using ternary alcohol mixtures with different eases of separation. Results show that conventional distillation sequences have more favorable controllability properties than those of the DWCs if direct separation and mixtures with symmetrical ease of separation are considered. In the cases of mixtures with nonsymmetrical ease of separation, the indirect separation, the DWCs with lower partition show practically similar controllability features than those of the corresponding conventional sequences.

show abstract

Applicability of Desirability Function for Control Structure Design in the Frequency Domain

Cited by 8 publications

References 27 publications

Comparison of Controllability Features of Extractive and Pressure Swing Distillations on the Example of Tetrahydrofuran Dewatering

Comparison of Controllability Features of Extractive and Pressure Swing Distillations on the Example of Tetrahydrofuran Dewatering

Effects of Energy Intensification of Pressure-Swing Distillation on Energy Consumption and Controllability

Dynamic Controllability Comparison of Conventional Distillation Sequences and Dividing-Wall Columns with Upper and Lower Partitions Using the Desirability Function

Contact Info

Product

Resources

About