Mean pore radius, relationship

If the pores have a well-defined shape there is a simple relationship between rh and the mean pore radius, rp. Thus, in the case of nonintersecting cylindrical capillaries... 

To examine the dependence of the mean reaction rate on the porous structure we should describe the relationships between all parameters of Equation 8.1 and the structural parameters mean pore radius, void fraction and surface area per unit particle volume 5. 

Relationship Between Mean Pore Radius, r, and Porosity, Pr. 

Angele et al showed that BET surface area decreases with increasing phosphorus content for three different catalysts. Figure 15. There is a linear relationship up to a high poison content. The experiment also showed that phosphorus reduced the porosity of the catalyst linearly. Figure 16 shows that the mean pore radius has increased, as phosphorus content becomes larger. 

If the inflection point of these curves is accepted as the mean pore radius, the relationship between this radius and the composition of the paste can be represented as shown in Fig. 8.10 [5]. 

Dependence of mean pore radius, r, found by nitrogen adsorption, on mean particle size of silica, D, determined by TEM. Broken lines show calculated relationship of r, to D for regular packings of spheres with coordination numbers of (a) 12 (hexagonal close packing), (b) 8 (body-centered cubic or random dense packing), and (c) 6 (simple cubic), r, is radius of largest sphere that will pass between particles. From Ramsay and Booth [36]. 

The mean pore hydraulic radius Fh for a porous solid is obtained through the relationship... 

The radius ro corresponding to the maximum value of curve in Fig. 7.9 is known as the most probable pore radius. It means that the proportion of the pore whose radius ro is the highest in the porous catalyst. In order to obtain the curve of pore size distribution, it needs to detect the contribution of a variety pore on the adsorption quantity, and then use the following ways to calculate the relationship of pore size distribution according to the scope of pore size of a variety of materials. 

The second approach to evaluate the distance between fibre contacts is to consider the pore sizes. White [6] proposed an interesting approach based on the specific surface of porous materials. He calculated the mean capillary radius of the porous structure, Rwhite, a theoretical radius deduced from the fibre radius, Rfiber, and the porosity, e, according to the following relationship ... 

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