Page 113 - Fluid Catalytic Cracking Handbook
P. 113
90 Fluid Catalytic Cracking Handbook
Figure 3-3. Silica-alumina ratio versus zeolite unit cell size,
aluminum atoms from separating from the zeolite lattice when the
catalyst is exposed to high temperature steam in the regenerator.
A fully rare-earth-exchanged zeolite equilibrates at a high UCS,
whereas a non-rare-earth zeolite equilibrates at a very low UCS in the
range of 24.25 [3]. All intermediate levels of rare-earth-exchanged
zeolite can be produced. The rare earth increases zeolite activity and
