An important phenomenon observed during the industrial usage of a FCC catalyst is its irreversible deactivation. The loss of activity suffered by the catalyst particles inside the unit is balanced by a continuous addition of fresh catalyst yielding a mixture of particles with different degrees of deactivation, normally called equilibrium catalyst. The deactivation of a FCC catalyst happens mainly in the regeneration section of the unit as a consequence of the high temperatures and the hydrothermal and highly oxidizing atmosphere existing in this equipment. The presence of contaminant metals, such as Ni, V, Fe and Na, on the catalyst is the other variable playing an important role in this deactivation process. Among these metals, vanadium is well known by its high zeolite deactivation properties. The destruction and dealumination of the framework zeolite, and the neutralization of the Bronsted acid sites are the causes that explain this irreversible loss in activity of the catalyst (2, 4, 5).
展开▼
