Distributed Models in Plantwide Dynamic Simulators

Modeling support for dynamic simulation of chemical-process flowsheets, which is of significant ®alue for plantwide dynamic simulation using differential ] algebraic model formulations, is to date ®ery limited when one or more unit models include partial differential equations. Se®eral new techniques that pro®ide modeling support for such simulations are presented. These techniques are based on a generalized characteristic analysis and a differentiation index analysis of partial differential] algebraic models. They can be used to unco®er systems that cannot be sol®ed as part of a dynamic simulation, and to determine whether or not the initial and boundary conditions supplied by the modeler form a well-posed problem. In a network flow context, they can further be used to select, enforce, and adapt the boundary conditions as required to maintain automatically a mathematically well-posed problem. Each of these pro®ides time-sa®ing support to the system modeler.