Numerical simulations were performed of a PSRI cold-flow FCC stripper experiment with subway grating baffles. Barracuda Virtual Reactor®, which implements the multi-phase particle-in-cell (MP-PIC) numerical method, was used to perform the simulations. Simulation results were compared with experimental measurements of apparent bed density over a wide range of solids flux conditions, at superficial gas velocities typical of industrial FCC stripper operation. The simulation results were in good agreement with the experimental bed density measurements, and matched the experimentally observed trends of bed density variation as a function of gas superficial velocity and catalyst mass flux through the stripper vessel.
This paper describes many structural issues which are endemic to the FCC operation resulting in limitations in operational flexibility with subsequent negative impact on economics including items such as incomplete combustion of spent catalyst within the regenerator commonly referred to as the “salt and pepper” appearance of regenerated catalyst, erosion of reactor or regenerator hardware leading to unscheduled shutdowns or reduced cycle length, and poor aeration at the inlets of regenerated catalyst hoppers and along the length of the standpipes leading to poor fluidization and reduced catalyst circulation rates.
A prominent refinery located in the eastern half of North America recently formed a team of FCC experts with the goal of identifying the root cause and delivering a solution to an exceptionally challenging case of maldistribution within their FCC regenerator. The result was a measurable reduction in the maldistribution resulting in a more stable operation with lower NOx, CO and particulate emissions. This approach may be an excellent model for other refineries facing similar issues within their FCC units.
This paper provides an overview of how afterburn presents itself in various operations describing both the stable and unstable forms of general or localized afterburn.
This work was originally presented at the 2016 AFPM Annual Meeting.
Predicting unexpected behavior in industrial deep-bed fluidization reactors and developing engineered solutions with CFD.
Simulation of a fluidized bed reactor for the deposition of high-purity silicon from silane gas.
A multiphase, thermal, and chemically reacting simulation of a commercial Fluidized Catalytic Cracking (FCC) regenerator was conducted.
Simulations for prediction of scaling effects in pharmaceutical fluidized bed processors at three scales.