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Theoretical investigation of non-uniform bifunctional catalyst for the aromatization of methyl cyclopentane

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Abstract

In this work, a mathematical model is considered to investigate the influence of the concentration and the non-uniform distribution of the catalytic sites on the performances of an isothermal fixed bed reactor with axial dispersion and mass transfer resistance under steady state conditions. This model is applied to the methyl cyclopentane aromatization network. The simulation of the model for a particular chemical reaction network showed that the catalyst activity depends on the balance between the number, per unit volume, of the active sites and the way they are distributed throughout the pellet. The model involves the use of two types of catalytic functions (bi-functional) and can be applied to any chemical reaction network related to catalytic reforming.

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Abbreviations

A i , A j :

Active species

\(C_{sI}\) :

Average concentration of the acid sites (site/cm 3)

\(C_{sII}\) :

Average concentration of the metallic sites (site/cm 3)

\(Bio\) :

Biot number

\(c_{i}\) :

Concentration of species A i inside the pellet (mol/cm 3)

\(c_{i,s}\) :

Concentration of species A i at the surface of pellet (mol/cm 3)

\(u_{i}\) :

Concentration of species A i in the fluid phase (mol/cm 3)

\(u_{i0}\) :

Concentration of species A i just before the entrance of the reactor (mol/cm 3)

\(u_{i} \left( 0 \right)\) :

Concentration of species A i at the entrance of the reactor (mol/cm 3)

\(U_{i}\) :

Dimensionless concentration of A i species in the fluid phase

\(X_{c} \left( \xi \right) = 1 - U_{1} \left( \xi \right)\) :

Conversion

Ψ i :

Dimensionless concentration of A i species in the solid phase

ρ :

Dimensionless radial position in the catalytic particle

\(\xi\) :

Dimensionless axial coordinate of the reactor

\(K_{L}^{*}\) :

Dimensionless mass transfer coefficient

\(\varPhi_{\ell }\) :

Dimensionless distribution function of the active sites

\(D\) :

Effective diffusion coefficient (cm 2/s)

\(D_{ea}\) :

Effective axial dispersion coefficient (cm 2/s)

\(a\) :

Indicates the half thickness of the catalytic pellet (cm)

\(r_{ij}\) :

Kinetic rate (mol/cm 3 s)

\(k_{ij}\) :

Kinetic constant (cm 3 / site s)

\(S\) :

Number of species

\(x\) :

Position in relation with the particle center (cm)

\(\varepsilon\) :

Porosity of the catalytic bed

\(\mu\) :

Parameter denoting the type of the distribution

\(Pe\) :

Peclet number

\(L\) :

Reactor length

\(\tau_{s}\) :

Residence time in the fluid phase (s)

\(\tau_{D}\) :

Diffusion time in the catalytic pellet (s)

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Authors and Affiliations

  1. Laboratoire de Génie des Procédés Chimiques, Département de Génie des Procédés, Faculté de Technologie, Université Ferhat Abbas Sétif 1, 19000, Sétif, Algeria

    T. F. Boukezoula & L. Bencheikh

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  1. T. F. Boukezoula
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  2. L. Bencheikh
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Correspondence to T. F. Boukezoula.

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Boukezoula, T.F., Bencheikh, L. Theoretical investigation of non-uniform bifunctional catalyst for the aromatization of methyl cyclopentane. Reac Kinet Mech Cat 124, 15–25 (2018). https://doi.org/10.1007/s11144-017-1308-6

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