A case study in control structure selection for a chemical reactor

Abstract

This paper describes the application of a systematic approach for control structure selection to an industrial reactor control problem investigated as part of a collaborative project between ICI and the Centre for Process Systems Engineering. The performance requirements are defined in terms of process constraints, an economic objective and a set of disturbances. The models required for the analysis are then developed. Following a qualitative analysis of the problem, a series of optimisation-based controllability tests are applied ranging from linear steady-state analysis to nonlinear dynamic analysis. These tests consider achievable performance with a multiloop PI(D) controller and with a linear multivariable controller. The performance of these two types of controllers is evaluated and the implications for control of the process is discussed. Finally, the effectiveness of the techniques used is reviewed based on experience on this application.