Control degrees of freedom using the restraining number: further evaluation

Vasudevan, Suraj; Konda, N. V. S. N. Murthy; Rangaiah, Gade Pandu

doi:10.1002/apj.117

Cited by 10 publications

(11 citation statements)

References 18 publications

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“…However, equation (5) is of limited practicality because it is not possible to manipulate all the streams simultaneously. This issue has been addressed by Konda, et al (2006) and Vasudevan, et al (2008) who recently proposed and examined a method which is flowsheet-oriented, and requires only the information of process flow diagrams and general knowledge of important unit operations. The idea is to identify the streams that are redundant or restrained from being manipulated.…”

Section: 222mentioning

confidence: 99%

Integration of process design and control: A review

Sharifzadeh

2013

Chemical Engineering Research and Design

116

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There is a large variety of methods in literature for process design and control, which can be classified into two main categories. The methods in the first category have a sequential approach in which, the control system is designed, only after the details of process design are decided. However, when process design is fixed, there is little room left for improving the control performance. Recognizing the interactions between process design and control, the methods in the second category integrate some control aspects into process design. With the aim of providing an exploration map and identifying the potential areas of further contributions, this paper presents a thematic review of the methods for integration of process design and control. The evolution paths of these methods are described and the advantages and disadvantages of each method are explained. The paper concludes with suggestions for future research activities. KeywordsIntegrated design and control, Sequential design and control, Control structure selection, Simultaneous optimization of a process and its controllers, inversely controlled process model, controllability.

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Section: 222mentioning

confidence: 99%

Integration of process design and control: A review

Sharifzadeh

2013

Chemical Engineering Research and Design

116

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“…One of the most important and foremost steps in the development of a PWC structure is the computation of CDOF. The CDOF of the process can be determined using the restraining number method , and the manipulated variables can be listed. The steady-state DOF can then be determined by subtracting the number of manipulated variables with dynamic effect only (mainly those related to level and pressure control).…”

Section: Proposed Integrated Pwc Methodologymentioning

confidence: 99%

“…The CDOF for the styrene process is determined to be 22. 20 Out of these, there are 11 steady-state DOFs: EB fresh feed flow, LPS fresh feed flow, feed LPS split ratio, furnace heat duty, intermediate heater duty, cooling water flow, T-1 compressor duty, and two DOFs each in columns T-1 and T-2 (i.e., the manipulated variables for maintaining distillate and bottoms compositions which are decided later by RGA).…”

Section: Application Of Ifsho To a Styrene Plantmentioning

confidence: 99%

Integrated Framework Incorporating Optimization for Plant-Wide Control of Industrial Processes

Vasudevan

Rangaiah

2011

Ind. Eng. Chem. Res.

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Numerous methodologies have been developed for the plant-wide control (PWC) of industrial processes. These methodologies can be classified into heuristics, optimization, mathematical, and mixed approaches. However, most of these methodologies do not involve the extensive usage of rigorous process simulators as part of the control system development. Also, in recent years, the focus has shifted toward the use of mixed approaches, which builds synergies between different techniques. As part of the continuing search for more effective PWC system design methods, an integrated methodology is proposed in this paper. This eight-level framework incorporates heuristics and optimization, together with the use of simulation throughout the procedure. The main intuitive feature of this framework is the identification of key controlled variables for optimal operation; this is achieved by detailed analysis of disturbances, computation of the new optimal set points by reoptimization, and cost breakdown analysis for throughput changes. Another important feature is the use of dynamic performance measures to aid in analyzing the effects of integration. This framework is then applied to the styrene monomer plant case study presented earlier [Vasudevan et al. Ind. Eng. Chem. Res. 2009, 48, 10941À10961] to develop a viable control structure. The performance of the resulting control system is compared with the control system developed using the integrated framework of simulation and heuristics. While both the control structures are found to be stable and robust in the face of disturbances, the control structure developed in the present work performs significantly better, in terms of steady-state profit and the dynamic economic index based on deviation from the production target.

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“…Konda et al 11. and Vasudevan et al 12. have published the restraining number for many common apparatuses.…”

Section: Control Structure Designmentioning

confidence: 99%

Control Structure Design for CO₂‐Absorption Processes with Large Operating Ranges

et al. 2013

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Coal‐fired power plants are operated flexibly over a large operating range, with variations in flue‐gas mass flow rate and composition. Postcombustion absorption processes are used to separate the CO2 from the flue gas at every operating point in the most economical way. Maintaining an economically feasible operation is the objective of the control structure. In this work the control structures were designed using a self‐optimizing control procedure for two process configurations. The control structures allow for an economic operation with a power‐plant load in the range of 40–100 %. The loss of the designed feedback‐control structures in comparison to an optimized control at every operating point was between 0.57 and 2.64 % in terms of cost of CO2 avoided.

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Control degrees of freedom using the restraining number: further evaluation

Cited by 10 publications

References 18 publications

Integration of process design and control: A review

Integration of process design and control: A review

Integrated Framework Incorporating Optimization for Plant-Wide Control of Industrial Processes

Control Structure Design for CO₂‐Absorption Processes with Large Operating Ranges

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Control degrees of freedom using the restraining number: further evaluation

Cited by 10 publications

References 18 publications

Integration of process design and control: A review

Integration of process design and control: A review

Integrated Framework Incorporating Optimization for Plant-Wide Control of Industrial Processes

Control Structure Design for CO2‐Absorption Processes with Large Operating Ranges

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Product

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Control Structure Design for CO₂‐Absorption Processes with Large Operating Ranges