Wall-catalyzed Reactions

We consider the case of a single heterogeneous wall-catalyzed reaction involving M species given by 

In the above equations, cjtS is the surface/wall concentration of species j, rw ( h,s, c2,s,---,Cm,s) is the dimensionless intrinsic rate of surface reaction, Das is the reactor scale Damkohler number, which are given by 

It should be noted that it is possible to eliminate (c) from Eq. (283) and write the model in two-mode form using cm and cs. For the simple case of single reaction A B, the two-mode model for a wall-catalyzed reactor is given by 

We now consider various limiting cases using the example of a single reaction B. 

The first limiting case we consider is that of steady-state limit with negligible axial dispersion (Per 1). For this case, Eqs. (286) and (287) reduce to the twomode form given by 

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Xu, Y, Platzer B., Concepts for the simulation of wall-catalyzed reactions in microchannel reactors with mesopores in the wall region, Chem. Eng. Technol. 24, 8 (2001) 773-783. 

We now consider the case of coupled homogeneous and wall-catalyzed reactions involving M species occurring in a tubular reactor. The homogeneous reaction is of the form... 

C. Non-isothermal Reactor Models 1. Wall-catalyzed Reactions... 

The low-dimensional model for non-isothermal wall-catalyzed reaction in a tubular reactor is given by Eqs. (283)-(285) and... 

We apply the low-dimensional convection model [Eq. (288)] to the simple case of a isothermal bimolecular wall-catalyzed reaction occurring in a tubular reactor. For the reaction... 

For the case of the wall-catalyzed reaction A — B, the global equation is closed for any type of kinetic expression rw(c). [Unlike the homogeneous reaction case, here the reaction rate r is evaluated at the surface concentration cs, which contains all the fluctuation modes (c ) about the mean .] Thus, convergence of the model depends only on the local equation. For the special case of linear kinetics, flat velocity, and Per -> oo, the local equation was determined to be... 

B. Platzer, Y. Xu, T. Rossmann, R. Fddisch, D. Honicke, Consideration of the effect of irregular catalytic active component distributions in mesopores -extension of a model for wall-catalyzed reactions in micro channel reactors, Chem. Eng. Technol. 2003, 26, 765-773. 

Mills PL, Nicole JF Multiple automated reactor systems (MARS). 2. Effect of microreactor configurations on homogeneous gas-phase and wall-catalyzed reactions for 1,3-butadiene oxidation, Ind Eng Chem Rjes 44 6453—6465, 2005b. 

The Tube Wall Catalyzed Reaction Assuming incompressible flow of a Newtonian fluid and no contributions in the azimuthal direction a mass balance for a differential element in the entrance region of the tube yields the following steady state dimensionless differential equation ... 

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