Numerical Simulation of the Effects of Deposits on the Flow Fields and Separation Performance of Cyclones in a Commercial RFCC Reactor

Abstract

AbstractCarbon deposits in Residue Fluidized Catalytic Cracking (RFCC) separators could be a safety hazard, they reduce efficiency, may also cause unscheduled shutdowns in industrial production. In this paper, the effect of coking on flow fields and separation performances was studied with an industrial cyclone separator. The time-averaged and dynamic flow-fields were affected significantly by the coking, as well as separation performance. The tangential and axial velocities decreased due to increased coking, with a maximum decrease of 102.9% and 60.7%, respectively. And the pressure drops decreased due to the vortex dissipation losses, with a maximum decrease of 33.8%. The vorticity also aggravated the breakage with the increasing coking as the breakage position moved up to the cone section. The instability of the flow-field affected the separation efficiency, and the separation efficiency, in turn, as a function of coking types, with a maximum decrease of 18.9%. With increased coking, both the pressure eccentricity and dynamic pressure standard deviation increased. And the main frequency of pressure fluctuation decreased from 37 Hz to 9 Hz. This study has the potential to further the understanding of the flow-field characteristics and performance for different coking types in cyclone separators.