Micro-scale discrete particle method (DPM) and meso-scale computational fluid dynamics (CFD) simulations

both based on the energy-minimization multi-scale (EMMS) model

were carried out on the complex gas-solid flow in the regenerators of fluid catalytic cracking (FCC)

aiming to provide visualized quantitative analysis for the performance improvement of the newly designed systems with unprecedented 7 Mt·a-1 throughput. For verification

a current 3.5 Mt·a-1 regenerator was first successfully simulated. Then

a 7 Mt·a-1 regenerator was simulated to investigate the performance of the air and solids distributors. The simulation results showed that increasing the gas ring number from 2 to 3 can improve the homogeneity of solids distribution significantly

while increasing the gas inlet number from 1 to 2 for the 3-gas-ring case made little improvement. For solid phase distributor

the injection of solids and their mixing with the internal material were simulated and analyzed. It was demonstrated that decreasing the hole fraction can effectively increase the resistance and improve the mixing performance. The necessity of understanding the detailed flow field around the nozzles for further improvements is demonstrated

and EMMS-DPM can be a powerful tool for this purpose.