CONSTRAINED MULTIVARIABLE CONTROL OF FLUID CATALYTIC CRACKING CONVERTERS

This paper concerns the development of a multivariable controller for the FCC Kellog Orthoflow F reactor/regenerator unit. A nonlinear dynamic model, based on the model of Kurihara, is used as a reference for the design of the control algorithm. This model is compared with the plant data, for open loop changes on the air flow and the regenerated catalyst valve opening. The adopted control algorithm incorporates both the regulatory and optimization functions. The regulatory layer is based on the usual DMC algorithm, while the optimization layer solves a linear programming problem, based on the DMC formulation, to perform steady-state economic optimizations. The calculated variables of the LP are the setpoints to the regulatory layer. The proposed control structure is simulated for a particular set of manipulated and controlled variables of the Kellog FCC converter and the results indicate good potential for the application to the real system.