FREQUENCY-RESPONSE STUDY OF MICROPORE AND MACRO-PORE DIFFUSION IN MANUFACTURED ZEOLITE PELLETS

Intra- and inter-crystalline diffusion of carbon dioxide and isobutane in different manufactured 5A and 13X pellets have been investigated b y the frequency-response method. Despite three orders of magnitude dif ference in micropore diffusivities for carbon dioxide in 5A and 13X ze olite crystals, its macropore diffusivities in 5A and 13X pellets are nearly the same. The macropore diffusivities were found to be the cont rolling step in all pellets under study. The diffusivity of carbon dio xide was found to be about twice that of isobutane in the macropores o f 13X pellets.