We consider a class of process systems with significant energy recovery. Revisiting our previous results concerning the two time scale dynamics of such systems, we demonstrate that the fast dynamics is asymptotically stable in most physically-relevant cases. On this basis, we propose a hierarchical controller design, comprised of a simple, linear control system for the fast dynamics and a MISO NMPC for the slow dynamics. We prove that this composite controller ensures exponential stability for the two time scale system. We establish a parallel between this approach and the concept of economic model predictive control, and show its implications in optimal energy management. Finally, we provide an illustrative simulation case study.