Quantitative assessment of controllability during the design of a ternary system with two recycle streams

In a previous paper (Elliott and Luyben, 1995), we outlined a generic methodology called the capacity-based economic approach that can be used to compare or screen preliminary plant designs by quantifying both steady-state economics and dynamic controllability. The method provides an analysis tool that explicitly considers variability in product quality. A simple reactor/stripper recycle system was used to demonstrate the method, In this paper, we consider a more complex recycle system consisting of a reactor and two distillation columns. The process was first studied in Tyreus and luyben (1993). The method is used to compare alternative flow sheets, alternative choices of design parameters, and alternative plantwide control structures.