This paper shows that reliable mechanistic models that take into account coke formation and the amount of strippable hydrocarbons can be built based on fixed-fluidized-bed laboratory tests if proper experimental designs and oil characterizations are provided. A methodology was implemented and used here to evaluate and to compare the performance of three distinct equilibrium fluid catalytic cracking (FCC) catalysts (e-cat) using different feedstocks. It is shown that phenomenological models (through their kinetic parameter estimates) can provide useful insights about the different catalyst performances during both the FCC and the catalyst stripping processes. It was observed that the deactivation parameter correlates well with the metal content of e-cat and that kinetic constants associated with the cracking of heavy components correlate well with the surface area and the microactivity of the e-cat.