Constructive nonlinear dynamics in process systems engineering

To date, sensitivity, bifurcation and singularity analysis have been employed to identify and characterize the qualitative nonlinear behaviour of chemical process systems. The phenomena of interest include multiple steady states and periodic or even chaotic oscillations. The analyses have been aiming at proper understanding of the relation between the observed behaviour on the one and the process parameters as well as the underlying physical-chemical phenomena on the other hand. These methods have rarely been used to address synthesis problems, neither in process design nor in process control, where a desired process behaviour has to be realized according to given design specifications in a constructive manner. The present paper reviews the authors' recent work on constructive nonlinear dynamics that extends and applies ideas from nonlinear dynamics to address synthesis rather than analysis problems. The suggested method systematically accounts for process economics and process operability in an integrated framework. Further, model as well as process uncertainties can be addressed systematically. The suggested formalism is illustrated by means of examples from various areas of process systems engineering including process design, controller tuning and the integration of design and control under uncertainty. Additional opportunities for future research and application are pointed out.