Abstract

A methodology for the evaluation of control strategies and for the preliminary assessment of con-trollability of nonlinear control affine systems was proposed. Due to the fact that the full nonlinear model of the process is used, the methodology is applicable to any steady state that is chosen as the set point. Also, there is no condition for the selection of controller used; therefore the methodology can be applied to any control structure selected for this process. An industrial system, fluidised bed catalyst regenerator, was used to illustrate application of this methodology. The choice and pairing of control and manipulate variables in lumped parameter chemical reactors, usu-ally Continuous Stirred Tank Reactors (CSTR), is not an easy task because of the lack of methodologies for a systematic evaluation of control schemes in nonlin-ear systems. Furthermore, intrinsic nonlinearities of this kind of systems could provoke responses to con-trol actions that are difficult to predict. The classical procedure to identify stable operating steady states