In this work, a fundamental kinetic model for the catalytic reforming process has been
developed. The complex network of elementary steps and molecular reactions occurring in
catalytic reforming has been generated through a computer algorithm characterizing the
various species by vectors and Boolean relation matrices. The algorithm is based on the
fundamental chemistry occurring on both acid and metal sites of the catalyst.
Rates are expressed for each of the elementary steps involved in the transformation of the
intermediates. The Hougen-Watson approach is used to express the rates of the molecular
reactions occurring on the metal sites of the catalyst. The single event approach is used to
account for the effect of structure of reactant and activated complex on the rate coefficients
of the elementary steps occurring on the acid sites. This approach recognizes that even if
the number of elementary steps is very large they belong to a very limited number of types,
and therefore it is possible to express the kinetics of elementary steps by a reduced number
of parameters. In addition, the single event approach leads to rate coefficients that are
independent of the feedstock, due to their fundamental chemical nature. The total number
of parameters at isothermal conditions is 45. To estimate these parameters, an objective
function based upon the sum of squares of the residuals was minimized through the
Marquardt algorithm. Intraparticle mass transport limitations and deactivation of the catalyst by coke formation
are considered in the model. Both the Wilke and the Stefan-Maxwell approaches were used
to calculate the concentration gradients inside of the particle. The heterogeneous kinetic
model was applied in the simulation of the process for typical industrial conditions for both
axial and radial flow fixed bed reactors. The influence of the main process variables on the
octane number and reformate volume was investigated and optimal conditions were
obtained. Additional aspects studied with the kinetic model are the reduction of aromatics,
mainly benzene. The results from the simulations agree with the typical performance found
in the industrial process.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/4670 |
| Date | 25 April 2007 |
| Creators | Sotelo-Boyas, Rogelio |
| Contributors | Anthony, Rayforf G., Froment, Gilbert F. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 1071184 bytes, electronic, application/pdf, born digital |
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