Title: Controlled variables selection based on lost work minimisation

Authors: Ayoub Safari; Reza Eslamloueyan

Addresses: Chemical Engineering Department, School of Chemical and Petroleum Engineering, Shiraz University, Shiraz, Iran ' Chemical Engineering Department, School of Chemical and Petroleum Engineering, Shiraz University, Shiraz, Iran

Abstract: An important phase of control structure design is the selection of controlled variables (CVs). The economic criteria and process profitability are extensively used for identifying the CVs selection. Nowadays, the exergy is another criterion for process optimisation. In this study, a novel technique is developed for incorporating the exergy efficiency and lost work in CVs selection during plant-wide control structure design. The basic concept behind the proposed method is to select the set of CVs that leads to the least process lost work when a process under feedback control encounters disturbances. In this way, at first the optimum operating conditions are determined by an economic objective function, and then CVs are specified by minimisation of the plant lost work. The study also presents a local approach for simplifying the solution of the obtained mixed integer nonlinear programming (MINLP).

Keywords: control structure design; controlled variables; CVs; lost work minimisation; exergy; self-optimising control.

DOI: 10.1504/IJEX.2018.095406

International Journal of Exergy, 2018 Vol.27 No.3, pp.334 - 363

Available online: 06 Sep 2018 *

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