Extended design cost: a performance criterion for real-time optimization systems

This paper presents a performance metric and design criterion for model-bas ed real-time optimization (RTO) systems, named extended design cost. Extend ed design cost is a systematic, comprehensive approach for evaluating the p erformance of RTO design alternatives based on fundamental principles from optimization, control and statistics theory. This metric is defined as the total toss in performance of the RTO system during some pre-specified evalu ation period due to design imperfections, and is shown to consist of contri butions from both the transient and steady-state behavior of the closed-loo p RTO system. The proposed method is demonstrated using several examples. T his paper concludes by presenting a systematic approach for selecting which model parameters to adjust on-line using extended design cost and the meth od is illustrated in the William-Otto reactor case study. (C) 2000 Elsevier Science Ltd. All rights reserved.