Development of guidelines for plantwide control of gas-phase industrial processes, from reactor-separator-recycle results

Abstract

The reactor-separator-recycle (RSR) process, consisting of a reactor and a separator/distillation column with material recycle between them, simplifies and idealizes real chemical plants. It is an important test bed used in plantwide control (PWC) studies. Though it has been actively studied in the past 15 years, appropriate guidelines on control structure selection are lacking, and there has been no consensus on the best control system. Also, there is still a need to study RSR processes with real components in practical context (that is, with more complete flow sheets) using rigorous process simulators. Another important aspect that has not been considered is the significance and usefulness of the results from RSR studies for real complicated plants. The main aim of this paper is to study the applicability of the RSR results to designing a PWC structure for a complete plant with heat integration besides a recycle. Findings of gas-phase RSR studies are applied to the toluene hydrodealkylation, ammonia, and styrene processes. The performance of the alternative control structures is analyzed for each process. Based on a comprehensive analysis of the results, useful guidelines for PWC design for gas-phase processes are developed. © 2010 American Chemical Society.