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Economic assessment of alternatives in optimizing control

Figueroa, J.L., Bahri, P.ORCID: 0000-0003-4661-5644, Barton, G.W. and Romagnoli, J.A. (1994) Economic assessment of alternatives in optimizing control. In: 4th European Symposium on Computer Aided Process Engineering (ESCAPE), 28 - 30 March, Dublin, Ireland pp. 207-212.


Chemical processes are usually designed to work at a specified set of conditions, fixed by a combination of plant behaviour, process variable constraints and economic objectives. The optimal steady-state operating conditions may be readily calculated using various commercial flowsheeting packages. However, as such optimal conditions are frequently characterized by operation at a number of active constraints, the presence of disturbances can easily cause constraint violation. Thus, it is necessary to move the operating point away from the active constraints and into the feasible region. The magnitude of this movement is called the `back-off' from the optimum. In this paper, we present an economic measure to show how much the objective function changes (as a result of back-off) for different control schemes. A method to design controllers with disturbance rejection capabilities is also discussed within the framework of back-off calculations. Results are given for a simple flowsheet example.

Item Type: Conference Paper
Publisher: Publ by Inst of Chemical Engineers, Rugby, United Kingdom
Conference Website:
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