Fluid catalytic cracking in a rotating fluidized bed in a static geometry: a CFD analysis accounting for the distribution of the catalyst coke content

Computational Fluid Dynamics is used to evaluate the use of a rotating fluidized bed in a static geometry for the catalytic cracking of gas oil. A Eulerian–Eulerian flow model is used in combination with the Kinetic Theory of Granular Flow. The catalytic cracking reactions are described by a 10-lump model. Catalyst deactivation by coke formation is included. To operate at low catalyst coke content, the catalyst residence time is small and the catalyst makes on average only a limited number of rotations in the reactor. Therefore, the catalyst bed cannot be considered well-mixed and a local distribution of the catalyst coke content is to be accounted for. The catalyst coke content distribution function has no pre-described functional form and is discretized. A continuity equation is then solved for each of the classes of catalyst with a given coke content. The impact of the strongly endothermic cracking reactions on the particle bed temperature uniformity is also studied.