Constrained nonlinear multivariable control of a fluid catalytic cracking process

In this paper, a nonlinear constrained optimization strategy is proposed and applied to the reactor-regenerator section of a ¯uid catalytic cracking (FCC) unit. A nonlinear dynamic model of the ¯uid catalytic cracking process was used for the dynamic analysis of the plant and nonlinear multivariable control system. The model realistically simulates the riser-reactor and the one stage regenerator by assembling the mass and energy balances on the system of reactions. The model results were tested in a real-time application and the results were used to provide the initial values for the nonlinear control system design. A dynamic parameter update algorithm was used to reduce the e€ect of large modelling errors by regularly updating the model parameters. The con- strained nonlinear optimization algorithm and strategies were tested in real-time on the ¯uid catalytic cracking reactor-regenerator. The results compared favourably to those from a linear multivariable controller.