(427e) Computational Analysis of the Air Injection Effect On the Regeneration Process in FCC

One of the problems associated with regeneration
process in conventional fluid catalytic cracking (FCC) unit is the increase of
flue gas temperature after leaving the dense catalyst bed, afterburning
phenomena. Generation of excessive heat of combustion and presence of smaller
number of catalyst particles to absorb this heat may degrade the quality of
catalyst, and require additional fresh catalyst to maintain the proper working
FCC unit. Hydrodynamic approach for gas-solid flows in fluidized bed is the best
way to comprehend regeneration process including afterburning problem, and
consequently a step-out improvement of the FCC regeneration. In this work, a regeneration process
in a simple type regenerator was
investigated by computational particle fluid dynamics (CPFD) numerical
simulation which is Eulerian-Lagrangian solution method for fluid-solid multiphase
flows. The combustion reaction was considered as a stoichiometric
equation in the simulation scheme. The simulated temperature profile of
catalyst and the particle-fluid coupled behaviour shows persuasive accuracy with
experimental data. Figures 1 and 2 below represent simulated temperature
profiles of gas and catalyst particle, respectively. The air distribution effect
on regeneration tendency was also demonstrated for various types of air sparger and air inlet flow rate conditions. The results reveal that adjustment of air flow gives significantly better temperature distribution, and hence
dramatically decrease ratio of the over-heated catalyst caused by afterburning effect.

Figure
 SEQ Figure \* ARABIC 1.
Temperature profile of catalyst particles

Figure
 SEQ Figure \* ARABIC 2. Temperature profile of gas

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