(24c) Detailed Modelling of Fluid Catalytic Cracking

The design and performance of the fluid catalytic cracking process (FCC) is studied by modelling the riser in detail. The selectivity and conversion of the cracking kinetics need to be coupled with the hydrodynamics to undertake reliable simulations of the process. Modelling the catalytic cracking of heavy oils is not an easy task, since it involves a very large number of components and reactions. The lumping kinetic approach, although unable to handle detailed reaction kinetics, is extremely powerful to simulate industrial FCC risers, for its ability to treat a large number of reactive networks. In this work, a novel approach which implements the continuum lumping kinetics in conjunction with CFD. The reactive systems is coupled with the complex hydrodynamics of the riser and experiments are implemented to validate the modelling framework. The results show non-uniformity of the gas-solid flow which affects the reaction temperature and residence time distribution. The methodology presented shows good ability to predict the product yields in an industrial FCC unit.