What are the advantages of fluidized bed reactors?

Advantages include: excellent heat transfer (can approach isothermal operation), good mass transfer between gas and solids, uniform temperature distribution (reduces hot spots), ability to continuously add and remove catalyst (for regeneration), handles fouling catalysts better (continuous circulation), and suitable for highly exothermic reactions. Applications: fluid catalytic cracking (FCC), polyethylene production, and coal combustion. Challenges include catalyst attrition, complex hydrodynamics, and potential for bypassing.