ABSTRACT
This introduction presents an overview of key concepts covered in this book. The book discusses four performance measures: steady-state flexibility index; volumetric flexibility index; dynamic flexibility index; and temporal flexibility index. Traditionally, the operational flexibility of a process is ensured in an ad hoc fashion by choosing conservative operating conditions, applying empirical overdesign factors, and introducing additional or redundant units. In process design, optimizing a single economic index is the most popular approach. However, as a general rule, the operability of a design deteriorates as the budget decreases and vice versa. Apparently, an additional quantitative measure is also needed to assess the operational performance of a practical system. The steady-state and volumetric flexibility indices (FIs and FIv) are applicable for characterizing the continuously operated chemical plants, whereas their dynamic and temporal counterparts (FId and FIt) are meant for evaluating the unsteady or batch processes.
