To investigate the performances of rough-cut cyclone in FCC disengager

two-fluid model provided by Fluent 6.2 was used for simulation of the dense phase flow.Agglomeration among particles was calculated by a set of improved gas-solid drag expressions.The results show that separation efficiency of rough-cut cyclone for catalyst reaches 98.48%.The solid concentration influences on the leakage of gases off dipleg are involved in three mechanisms: weakening on the gas swirling motion

dragging forces fundamentally caused by the particle gravitation and the wrapping effects onto the gas.The leakage ratio of the dipleg is 32.17% and it can be reduced to 20.97% by adding a hopper.It is proved that the concentration turning point for pressure drop is a function concerning particle density

viscosity and granular sizes.Pressure drops of rough-cut cyclone calculated by the wall film growth theory have good agreement with numerical simulation results.