Exact I/O-linearization of chemical processes within a plant-wide quality control framework

In this paper a process control concept for plant-wide quality control is presented and illustrated with a simple example process consisting of a continuous stirred tank reactor (CSTR), two distillation columns (DCs) and a recycle stream from one separation unit back into the reactor. The concept is based on a formal definition of product quality as an intensive state function in the thermodynamic sense. This quality function is evaluated for each product stream in a chemical plant and is used as the plant-wide controlled variable. The concept involves two hierarchically ordered levels using exact I/O-linearization (EIOL) for local control systems and LQ methods on the superior coordination level