ChBE Seminar Series: Erik Ydstie
Tuesday, March 25, 2008
11:00 a.m.-12:00 p.m.
Room 2110 Chemical & Nuclear Engineering Bldg.
Professor Ray Adomaitis
Stable and Robust Control and Optimization of Chemical Processes
Presented by Erik Ydstie
Department of Chemical Engineering
Carnegie Mellon University
Professor Ydstie will show how physics, communication and control are integrated in complex process networks. The Boltzmann entropy defines a dissipation function which links thermodynamics and the passivity theory of nonlinear control. The link implies that little central coordination is required to solve complex networked problems. In this theory the conservation laws play the role of Kirchoffs current law whereas the continuity of the entropy allows us to derive the voltage law. Classical results from nonlinear circuit theory (Tellegens theorem for multi-port systems and variational calculus) are then used to show that the flow distribution automatically stabilizes so that the dissipation is minimized. By making analogies amongst process control, network thermodynamics and business decision making we use the minimum dissipation principle to show that distributed inventory and flow control can give robust feedback systems that adapt and self-optimize. Some industrial applications are discussed briefly.