Multivariable Control Structure Design of Heat Exchange Networks Based on Mixed-Integer Quadratic Programming

BRACCIA, LAUTARO; MARCHETTI, PABLO A.; LUPPI, PATRICIO; ZUMOFFEN, DAVID

Computer-Aided Chemical Engineering 44

Elsevier

Año: 2018; p. 601 - 606

In this work, a new systematic methodology to address multivariable control structure(MCS) design for heat exchange networks (HENs) is proposed. This methodology isbased on recent developments presented by Braccia et al. (2017) where the MCS designfor medium/large-scale processes is performed based on a mixed-integer quadraticprogramming (MIQP) formulation. This methodology is based on an equation-orientedsuperstructure which addresses simultaneously: the selection of controlled variables(CVs) and manipulated variables (MVs), the input-output pairing definition, thecontroller topology, the initial heuristics considerations, and the stability test by usingsteady-state information only. Usually, in the HENs cases, all the outputs variables needto be controlled, i.e. there are no uncontrolled variables. In this context, the MCS designprocedure presented in Braccia et al. (2017) requires a reformulation to quantify themanipulated variables instead of the uncontrolled variables. Furthermore, somemodifications of the original MIQP algorithm related to the augmented functional costare analyzed. The performance of different controller topologies, i.e. decentralized,sparse, and full, are evaluated. Two examples are given in this work to illustrate thepotential of the proposed methodology and to support the final conclusions.