A porous catalyst is used for CO oxidation, and the process is modeled as a first-order reaction with a rate constant of 2 × 104 s−1

A porous catalyst is used for CO oxidation, and the process is modeled as a first-order reaction with a rate constant of 2 × 104 s−1. The effective diffusion coefficient for pore diffusion was estimated as 4 × 10−6 m2/s. The catalyst is exposed to a bulk gas at 600 K and 1 bar pressure with a CO mole fraction of 2%. The external mass transfer coefficient is assumed not to be rate limiting. Find the rate of reaction for a spherical pellet of diameter 3 mm. Express the rate as moles reacted per catalyst volume per second. Find the effectiveness factor. Find the effectiveness factor if the catalyst diameter were changed to 1 mm. Estimate the range of values of the external mass transfer coefficient for which this resistance can be neglected.