Economic model predictive control of a transport-reaction process

This work focuses on the development and evaluation of an economic model predictive control (EMPC) system for a non-isothermal tubular reactor where a second-order chemical reaction takes place. The tubular reactor is modeled by two nonlinear parabolic partial differential equations (PDEs). Galerkin´s method is initially used to derive finite-dimensional systems that capture the dominant dynamics of the parabolic PDEs which are subsequently used for EMPC design. The EMPC formulation uses as an economic cost function the integral of the reaction rate along the length of the reactor over a certain operation interval subject to constraints on the control action (reactant concentration in the feed to the reactor). Closed-loop simulations in which the low-order EMPC system is applied to a high-order discretization of the PDEs demonstrate that the EMPC operates the process in a time-varying fashion and improves the economic cost over steady-state operation using the same amount of reactant material over a fixed period of operation.