Surface area per unit mass of catalyst

Ss = tlie surface area per unit mass of catalyst Sex = the external surface area of catalyst. 

Most important, heterogeneous surface-catalyzed chemical reaction rates are written in pseudo-homogeneous (i.e., volumetric) form and they are included in the mass transfer equation instead of the boundary conditions. Details of the porosity and tortuosity of a catalytic pellet are included in the effective diffusion coefficient used to calculate the intrapellet Damkohler number. The parameters (i.e., internal surface area per unit mass of catalyst) and Papp (i.e., apparent pellet density, which includes the internal void volume), whose product has units of inverse length, allow one to express the kinetic rate laws in pseudo-volumetric form, as required by the mass transfer equation. Hence, the mass balance for homogeneous diffusion and multiple pseudo-volumetric chemical reactions in one catalytic pellet is... 

The rate of mass transfer to the surface is expressed using either concentration or partial pressure as a driving force. The term a is the external surface area per unit mass of catalyst ... 

In these equations, a is the external surface area per unit mass of catalyst (m /g), k is the gas-phase mass transfer coefficient based on unit external surface area (m/s), k r is the apparent rate constant of the surface reaction per unit external surface area (m/s), and Qs and Cbs are the surface concentrations of A and B (mol/m ), respectively. 

Catalyst Surface Area Per Unit Mass of Catalyst versus Mass Ratio of Platinum to Carbon Support... 

Platinum mass loading in terms of catalyst surface area per unit mass of catalyst particles is obtained from experimental evaluation of active layer structure. A typical empirical correlation for such a structure is given as (Marr and Li, 1999 Secanell et al., 2007)... 

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