Dynamic modeling and nonlinear model predictive control of a fluid catalytic cracking unit

The paper presents the application of nonlinear model predictive control (NMPC) to a simulated industrial fluid catalytic cracking unit (FCCU). A complex dynamic model of the reactor-regenerator-fractionator system is developed and used in the controller. The novelty of the model consists in that besides the complex dynamics of the reactor-regenerator system it also includes the dynamic model of the fractionator, as well as a new five lumped kinetic model for the riser, and hence it is able to predict the final production rate of the main products (gasoline and diesel). Simulation results presented in this paper demonstrate that a numerically efficient, inferential NMPC approach that regulates easily measurable variables in the reactor and regenerator is able to provide good control of the product composition for certain disturbance scenarios.