A spherical porous catalyst particle of radius R is subjected to reactant A which reacts to form B by a zero order surface reaction A → B. Film mass transfer resistance is negligible and pore diffusion of A is rate controlling. The effectiveness factor of the catalyst is reported as 7/8. Which of the following statement is true?

Question

Accepted Answer

Inner catalyst core of radius R/8 does not participate in reaction. For a zero-order reaction with strong pore diffusion resistance, the effectiveness factor is given by eta = 1 - (r_c/R)/3. Setting eta = 7/8 yields r_c/R = 1/8, meaning the inner core of radius R/8 is inactive.