Deactivation kinetics

Activity of catalysts pellet at any time is defined as

Reaction rate can be considered as function of temperature, reactant concentration and present activity of the catalysts pellet. Therefore for n th order reaction, rate can be written as

Where a is the present activity of the catalysts.

Similarly deactivation rate can be considered as function of temperature, concentration of substance that deactivates the catalysts (which can be reactant, product or impurities) and present activity of the catalysts pellets. Hence deactivation rate can be given as,

i = A (reactant),R (product) ,P(3^rd substance)

Here d is called order of deactivation, k_d is deactivation rate constant and n΄ is the concentration dependency.

 

Deactivation reaction rate for different types.

1.   Parallel ,

Reaction rate is

Deactivation rate is

d = order of deactivations

2.   Series

Reaction rate is

Deactivation rate is

3.   Side-by-side deactivations ,

Reaction rate is

Deactivation rate is

 

4.   Independent deactivations

Reaction rate is

Deactivation rate is