Nitrogen vs. argon adsorption for matrix surface area determination of deactivated FCC catalysts containing ZSM-5

Abstract

Nitrogen adsorption is the standard method in the refining industry to measure the surface area of FCC catalysts and additives. However, due to the quadrupole moment of nitrogen and the complex adsorbate-adsorbent interactions, the t-plot method can significantly overestimate the matrix surface area (MSA) of deactivated, ZSM-5 containing FCC catalysts. In this study, two sets of deactivated FCC base catalyst/additive blend samples were analyzed using both nitrogen and argon as adsorbate. The results show that the t-plot from argon adsorption evades the inflection point observed with nitrogen adsorption, thus providing more reasonable estimation of catalyst MSA.