Infinite horizon MPC control of a heat-exchanger network

GONZÁLEZ, ALEJANDRO HERNÁN; ODLOAK, DARCI; MARCHETTI, JACINTO LUIS; SOTOMAYOR, OSCAR

Glasgow, Escocia

Congreso; 7th World Congress of Chemical Engineering; 2005

Abstract:   A method to control a heat-exchanger network (HEN) is presented where both, the control objective and the economic objective are taken into account. It is assumed that we have a two-level structure in which the steady state economic optimisation is performed in the upper level and a MPC controller is used to enforce the optimal operating point defined by the economic layer. Since HENs are multivariable highly interactive systems, which integrate large energy consumers of a process plant, stability of the proposed structure becomes one of the issues of the HEN control problem. In this approach, integration is achieved through the definition of an extended cost-function that provides the ability of driving the system to optimal conditions. The proposed MPC algorithm uses a linear state space model that is particularly suitable to the development proposed in this work. The method is exemplified with the simulation of a HEN system that shows the typical characteristics of an industrial system.