Effects of gas in-leakage on separation performance and gas-phase flow field of a FCC cyclone

Effects of gas in-leakage on pressure drop and separation efficiency of the cyclone separator were experimentally investigated to help to identify the separation faults in commercial FCC units. The results show that the pressure drop slightly decreases with the increase of gas in-leakage rates from 0 to 8%. Meanwhile, the separation effi-ciency shows a limited decline within 2% gas in-leakage rate but a sharp decrease exceeding 4%. Furthermore, gas-phase flow fields at different gas in-leakage rates were revealed by CFD method using Reynolds Stress Model. The variation of flow field with gas in-leakage rates was analyzed and the effect of flow field on the separation performance was also discussed. Finally, an industrial case about catalyst loss were introduced to illustrate the effect of gas in-leakage on the separation performance of cyclone separator. To avoid severe separation failure, it is better to restrict the gas in-leakage rate to 4%.