Several factors can influence the rate of external diffusion:
Fluid velocity: Higher fluid velocities can reduce the thickness of the boundary layer around the catalyst particle, enhancing diffusion rates. Particle size: Smaller catalyst particles have a higher surface area-to-volume ratio, which can facilitate better mass transfer. Viscosity: Higher viscosity fluids can impede mass transfer, reducing the rate of external diffusion. Temperature: Increasing temperature generally enhances diffusion rates due to increased molecular motion. Concentration gradient: A higher concentration gradient between the bulk fluid and the catalyst surface can drive faster diffusion.
