A systematic model-based analysis of a downer regenerator in fluid catalytic cracking processes

Performance improvement of a catalyst regenerator for gasoline production in a fluid catalytic cracking (FCC) process is needed to achieve higher burning efficiency. This study performed a systematic model-based analysis of a downer-type regenerator to recover the activity of FCC catalyst by using a one-dimensional model of the regenerator coupled with its hydrodynamic characteristics and the kinetics of catalyst regeneration. The results of a sensitivity analysis showed that higher carbon content on spent catalyst causes a higher regeneration temperature. The ratio of the recycled-to-spent catalyst flow rate in range of 1.0–3.5 and temperatures of the spent catalyst in range of 703.15–803.15 K have insignificant effects on the overall performance of the regenerator. The suitable superficial gas velocity and the spent catalyst flow rate are in range of 4–7 m s−1 and 20–40 kg m−2 s−1, respectively.

► Performance of a novel downer regenerator to reactivate FCC catalyst was studied. ► Hydrodynamic of the regenerator and kinetics of catalyst regeneration was explained. ► Effects of key operating parameters on catalyst regeneration efficiency were reported. ► Temperature of the downer regenerator has a key effect on a regeneration process.