Macrokinetic equation of catalytic reactions

At steady state, for a gas olid catalytic process, the amount of reactive components diffusing from bulk gas to external surface of catalyst actually equals to the amount consumed within particle of catalyst  

Equation (2.214) is a macrokinetic equation involving the effects of transfer processes. 

If first order reversible reactions are assumed, the concentration function in kinetic equation can be expressed as  

It can be seen from Eq. (2.214) or (2.215) that the processes are in various controlling regions by chemical kinetics, internal diffusion or external diffusion for various values of kg, Sg, kg, Sg and C- 

This case happens if the coefficient of external mass transfer kg is considerably large and the catalyst particles are smaller i.e., the effects of internal and external diffusion have been eliminated. 

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