Anisotropy of a Ringshaped Catalyst Pellet

Can the gas be considered as nondiluted The maximum value of yf will be obtained for very broad catalyst pores (KnA 0) and, again, at the reactor inlet  

Therefore, from criteria 7.114 and 7.117 it follows that for the oxidation of ethylene the gas may be regarded as a diluted gas. 

Reconsider the ring-shaped catalyst pellet given in Example 9.8, for which 

Assume the catalyst pellet to be anisotropic. The radial effective diffusion coefficient is De R = 5x10 m2 s 1 the longitudinal effective diffusion coefficient equals DeAH = 1.8xl0 6 m2 s 1. Then, if the effective diffusion coefficient is determined from measurements of the effectiveness factor, this gives 

Now change the catalyst geometry and increase the height twofold. What will be the consequence if the anisotropy is overlooked and what will be the correct value for the effectiveness factor. 

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