Bragg-Williams lattice gas

There are serious difficulties in the derivation of the multi-component adsorption (which is typical of the reforming scenario), taking into account the role of adsorbate interactions. The only mathematically tractatable way to do it is, by following the Bragg-Williams lattice -gas Mean field field Approach (MFA). In this approach, the pair and higher-order correlations between the adsorbed molecules are ignored. With these assumptions, the adsorption isotherms within the MFA format can be easily written(8-l 1,17)... 

The greatest barrier in the application of the Multicomponent Fowler-Guggenheim or Bragg-Williams Lattice gas model to, a practical situation like Pet-reforming, is the absence of experimental interaction parameters. In the simulations of the earlier sections, representative values were used. In general, for an n component system, we need to fix n(n+l) / 2 interaction parameters of the symmetric W matrix (91 for a 13 component Model ). Mobil has used successfully a 13 lump KINPTR model(5), which essentially uses a Hougen-Watson Langmuir-Hinshelwood approach. This results in a psuedo-monomolecular set of reactions, which is amenable to matrix analysis. 

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