(133e) Predicting Performance of Industrial FCC Regenerator Using Computational Fluid Dynamics

In the Fluid Catalytic Cracking (FCC) process, uniform regeneration of spent catalyst is key to the successful operation of the FCC units. The degree and uniformity of catalyst regeneration has a substantial impact on the product yields. The regenerator combustion efficiency strongly depends on good distribution of both air and spent catalyst, and air catalyst mixing and flow patterns within the regenerator are greatly influenced by both process conditions as well as regenerator hardware configuration. Therefore, understanding the regenerator hydrodynamics and kinetics, and the impact of hardware modifications on regenerator performance is essential for efficient regenerator design, optimization and troubleshooting.

In this work, a CFD based kinetic tool has been developed to simultaneously model both hydrodynamics and coke combustion characteristics in the FCC regenerator. The tool enables us to evaluate the influence of the fluidized bed hydrodynamic on the catalyst regeneration in an industrial FCC regenerator, and serves as a useful tool for future technology development. TechnipFMC employed Barracuda CFD software and coupled the code with proprietary coke combustion kinetic equations and rate constants, developed experimentally at IFP Energyies nouvelles (IFPEN). TechnipFMC and IFPEN have tested and compared the model against several commercial regenerator designs. This study also provides an example of how the CFD based kinetic tool is used in the modeling of an industrial FCC regenerator. The results provide detailed qualitative mapping of the regenerator behavior in terms of flue gas composition, temperature distribution including afterburning, and regenerator bed density in both axial and radial planes. The results proved to be instrumental to recommend hardware and operational modifications.