Methane Formation versus Fischer-Tropsch Kinetics

2 Methane Formation versus Fischer-Tropsch Kinetics 

Hie apparent rate of C-C bond formation can be faster or slower than the rate of CO transformation to CH intermediates. In case the former is higher, expressions (16.15) for a and Rqq are to be used. This is the chain growth kinetics model. When the rate of CO dissociation is slower, FT kinetics behaves according to the polymerization model (Eq. (16.16)). 

The question that arises is whether there is a relation between the Sabatier maxima found in catalytic reactions when reagent activation and product formation have comparable rates [36, 43] and the temperature maximum of the reaction. The Sabatier maximum relates to changes in surface coverage when surface reactivity changes. 

We will illustrate first the physical chemistry that determines the temperature of the maximum rate for methane formation and then extend the analysis to the FT reaction. The lumped microkinetics expression for the rate of methane production is given by Eq. (16.21). 

One notes from Eq. (16.21) that the rate of methane formation is equal to 

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