Steady-state process optimization with guaranteed robust stability and feasibility

• Published in: AIChE journal Vol. 49; no. 12; pp. 3110 - 3126
• Main Authors: Mönnigmann, M., Marquardt, W.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-12-2003; Wiley Subscription Services; American Institute of Chemical Engineers
• Subjects: Applications of mathematics to chemical engineering. Modeling. Simulation. Optimization; Applied sciences; Chemical engineering; Exact sciences and technology; Design; Continuous process; Uncertainty; Robust stability; Stability boundary; Robustness; Flexibility; Steady state; Optimization
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.690491212

A new approach is presented to the optimization based design of continuous processes in the presence of parametric uncertainty. In contrast to previous works focusing on process feasibility, it allows to consider both feasibility and stability of the process in the presence of parametric uncertainty. The new approach, therefore, permits an integrated treatment of steady‐state flexibility and robust stability in the optimization of continuous processes. The process optimization problem is extended by constraints that ensure a lower bound on the distance of the nominal point of operation to stability and feasibility boundaries in the space of the uncertain parameters. While previous approaches are based on evaluating constraint violation in the range space of the constraints, the measure for flexibility and robustness used here is given in the domain space of the uncertain parameters. The method is discussed in the context of existing approaches to flexibility in process optimization and is illustrated with a continuous polymerization which is known to have a nontrivial stability boundary resulting from multiple steady states and sustained oscillations.