Advanced model for turbulent gas–solid flow and reaction in FCC riser reactors

Abstract

AbstractA 3‐D two‐phase flow‐reaction model was developed for predicting the performance of FCC riser reactors. This model combines two‐phase turbulent flow with 13‐lump reaction kinetics. The simulated results show that the gas–particulate turbulent reacting flow regime in the riser reactor is extremely complex, especially at the feed inlet zone of the riser reactor. The distributions of velocities, temperature, and yields are not homogeneous in the riser reactor. The model predictions were used as a design tool for operational case studies. The optimum yields of desirable FCC products, gasoline and light fuel oil were achieved at a critical riser height that is less than 10 m above the feed inlet. Beyond the critical riser height, excessive cracking reactions resulted in the increased yields of by‐products, cracking gas and coke, at the expense of desirable products. Model simulations carried out to determine the parametric effects on product yields suggest that injection of water as a reaction‐terminating medium above the critical riser height can be an effective option for optimizing the yields of desirable products.