Computation Fluid Dynamic Modeling Improves FCC Technology and Profitability

Computational Fluid Dynamic (CFD) modeling is a powerful tool for equipment design and development and is widely used at UOP, particularly for the reactor and regenerator design of FCC process unit. Through CFD modeling, a technical solution was developed for a large capacity FCC process unit purposing an elevated amount of propylene production. 

 A key challenge in FCC process design is how to optimize the size of the reactor vessel, which is determined by number and size of reactor cyclones.  UOP developed a new cyclone cluster configuration via CFD study of the reactor internals, including UOP’s VSS™ riser termination device and reactor cyclones, which reduce the reactor size significantly compare to the conventional design, while maintaining effective catalyst / vapor separation and mechanical reliability.  The objective of the current CFD study is to evaluate the catalyst separation efficiency and performance of the new riser termination device technology, which accommodate more cyclones in a smaller reactor vessel.

 To better understand the flow pattern, flow distribution and the gas residence time inside the UOP VSS^TM , the analysis was broken down into two sections. Part 1 focused on single gas phase only and in part 2 the particles behavior is studied using the DPM model in Fluent.

The single gas flow analysis results showed that the flow in the chamber section has a rotational pattern as in conventional FCC/VSS units, where the catalyst will separate from the gas products, and the chamber pipes don’t have an effect on the flow pattern inside the vessel. Also the gas flow distribution at each chamber arm is uniform.

The DPM analysis showed an equal catalyst particle distribution through the cyclones and high efficiency separation in the riser termination device a proper catalyst separation technology.