Study on the FCC Process in a Novel Riser-Downer-Coupling Reactor (II): Simulation and Hot Experiments

In this paper, a two-dimensional dispersion model is developed to simulate the FCC process occurring in the riser-downercoupling reactor based on the hydrodynamics and mixing behaviors described in the previous paper as well as an 11-lump reaction kinetics model. The merits and defects of both riser and downer are discussed on the basis of the simulation results. It can also be concluded from the calculation that the coupling reactor can take advantage of both the riser and downer to offer the highest yields of desired products using the conventional FCC catalyst; furthermore, the coupling reactor can be flexibly operated to match various stock supplies and product requirements by adjusting the lengths of the riser and the downer. The performance of the coupling reactor in the FCC process was tested in a pilot plant with the capacity of 150 000 ton/year.