(419g) Industrial Practice and CFD Investigation of a Novel Fast Fluidized Bed for Fluid Catalytic Cracking

Fluid Catalytic cracking (FCC) is a crucial technology for producing propylene from heavy oil. The riser is widely used in FCC technology due to its high gas-solid flux and short particle residence time. However, the low gas-solid contact efficiency of the riser is prone to thermal cracking reactions, resulting in producing more dry gas and coke, which limits the improvement of propylene selectivity. Based on the idea of enhancing gas-solid contact efficiency, a novel fast fluidized bed was proposed to improve propylene yield, and the industrial practice and CFD investigation were performed. The industrial practice results showed that in comparison with the typical riser technology, the yield of ethylene and propylene increased by 0.5 and 2.56 percentage points respectively, and the gasoline research octane number (RON) increased by 0.4. Besides, dry gas and coke decreased. To analyze differences between the conventional riser and the novel fast fluidized bed, a structure-based transfer model coupled with 3D CFD was established. The simulation results showed that the model predicted the gas-solid flow behavior more accurately than the traditional model. The computed solids concentration and particle residence time in the novel fast fluidized bed were higher than those in the riser, indicating that the novel fast fluidized bed exhibited higher gas-solid contact efficiency. Therefore, the results suggest that the novel fast fluidized bed has promising potential for propylene production.