An extended algorithm of flexibility analysis with a local adjusting method for flexibility
region of chemical processes, which is based on the active constraint strategy, is
proposed, which fully exploits the flexibility region of the process system operation. The
hyperrectangular flexibility region determined by the extended algorithm is larger than
that calculated by the previous algorithms. The limitation of the proposed algorithm due to
imperfect convexity and its corresponding verification measure are also discussed. Both
numerical and actual chemical process examples are presented to demonstrate the
effectiveness of the new algorithm.