Chemical Reaction and Diffusion inside a Catalyst Particle

1 Chemical Reaction and Diffusion inside a Catalyst Particle  

The diffusion resistance in the fluid film around the particle, as well as inside the particle, is the reason why the concentrations of the reactant molecules inside the particle are lower than those in the main bulk of the fluid. The result, in the case of most common reaction kinetics, is that even the reaction rates inside the pores assume lower values than what would be expected for the concentration levels of the main bulk. 

FIGURE 5.20 Phase boundary in a porous catalyst particle. 

Equation 5.22 is often called Pick s law (Chapter 4). More advanced diffusion models are presented in the literature [ 10]. 

The catalyst mass inside the volume element can be expressed by the density of the catalyst particle (pp) and the element volume  

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Chemical reaction and diffusion inside a catalyst particle... 

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