A new algorithm for computing process flexibility

In the design of a chemical process (CP), certain design specifications (fo r example, those related to process economics, process performance, safety, and the environment) must be satisfied. During the operation of the plant, because design models have uncertainties associated with them, we need to ensure that, within the region of uncertainty, all design specifications ar e satisfied. In recent years, research has focused on the investigation of the process flexibility (Biegler et al. Systematic Methods of Chemical Proc ess Design; Prentice Hall: Englewood Cliffs, NJ, 1997) based on the feasibi lity function (Halemane and Grossmann AIChE J. 1983, 29 (3), 425) which is a measure of the CP's ability to meet design specifications under uncertain ty. Several researchers have proposed methods for calculating the process f easibility function, which involves solving a very complex multiextremal an d nondifferentiable optimization problem. Current methods for calculation o f the flexibility function use an enumeration procedure (explicit or implic it), which in the worst case can require a large number of iterations. To t ry to address this issue, in this paper, we have introduced an efficient ap proach, which avoids enumeration. Through examples, we have shown that the new method leads to a small number of iterations and has low CPU requiremen ts.