This paper focuses on the dynamics and control of process networks consisting of a reactor connected with an external heat exchanger through a large material recycle stream that acts as an energy carrier. Using singular perturbation arguments, we show that such networks exhibit a dynamic behavior featuring two time scales: a fast one, in which the energy balance variables evolve, and a slow time scale that captures the evolution of the terms in the material balance equations. We present a procedure for deriving reduced-order, non-stiff models for the fast and slow dynamics, and a framework for rational control system design that accounts for the time scale separation exhibited by the system dynamics. The theoretical developments are illustrated with an example and numerical simulation results.
Bibliographical noteFunding Information:
Partial support for this work by ACS–PRF, Grant 38114-AC9 and NSF–CTS, Grant 0234440 is gratefully acknowledged.
- Energy recycle
- Model reduction
- Nonlinear control
- Singular perturbations