(551h) Understanding Particle Attrition in FCC Operations

Catalyst attrition in FCC units has been a long-standing challenge.  It can compromise downstream equipment, increase operating costs with catalyst replacement and lead to high particulate (i.e., catalyst) emissions. With such problems, improvements would be expected or even demanded.  However, it is not straightforward where those improvements can be applied.  

Recent research at PSRI has been focused on what typically needs improvements and how to identity those opportunities.  It’s a process that involves understanding the gas and solids hydrodynamics in the FCC unit while performing laboratory testing that is relevant to those operations.  Population balance models can also be used to understand the pathway of fines generation in both the FCCU and the laboratory setting.  Analogous to a reaction kinetic model, this technique can be used to distinguish the relative rates of attrition via particle fracture versus abrasion.  After applying the model to commercial units, it was found that attrition can occur in varying proportions of fracture and abrasion.  Abrasion is typically indicative of minor operational issues whereas fragmentation is an indication of a design issue.