(53f) Improving FCC Regenerator Performance and Capacity Utilization through CFD Analysis

Fluidized Catalytic Cracking (FCC) plays a significant role in crude oil refining, converting large oil molecules into economically favorable smaller molecules that will satisfy the daily commuting and transportation needs of consumers. Full utilization of the FCC capacity is critical for meeting the daily production requirements from the refinery. The FCC regenerator can be the source of capacity underutilization if it is negatively impacted by the performance of its internals. Internals that promote uniform catalyst distribution are crucial for achieving efficient, reliable spent catalyst regeneration and thus consistent quality catalyst circulated to the reaction system. Regeneration constraints are in turn mitigated (like afterburning) and the lifespan of equipment prolonged.

Shell utilizes Computational Fluid Dynamics (CFD) technology to assess and improve conventional and transitional FCC operations. CFD has become an indispensable engineering tool to optimize the equipment design as well as study the fluidization behavior over a wide range of applications. To illustrate the value delivered by CFD, we will review the performance and mechanical integrity of an existing spent catalyst distributor in an FCC regenerator along with the CFD model created to benchmark its performance. A second CFD model that incorporates a Shell-designed spent catalyst distributor will also be presented and compared to the existing design, focusing mixing, catalyst distribution, and flow behavior. The upgraded distributor was shown to be advantaged in catalyst distribution with improved mechanical integrity, this providing the refiner the opportunity to increase FCC utilization and optimize unit operation overall.