Numerical analysis of droplet–particle collision total forces in Fluid Catalytic Cracking units

In the riser reactor of the Fluid Catalytic Cracking (FCC) process, gas oil is injected at high velocity and pressure to promote atomization into fine droplets, increasing interfacial area and accelerating evaporation. However, some droplets may reach the catalyst before complete evaporation, causing impact events. The literature debates whether these impacts involve direct contact or the Leidenfrost effect, in which a vapor layer separates the liquid from the particle. Assuming direct contact, this work investigates whether droplet impact can mechanically stress the catalyst. Results indicate an approximately 6 % probability of catalyst breakage for droplet velocities above 80 m/s.