Page 132 - Fluid Catalytic Cracking Handbook

FCC Catalysts 101

Pore Volume (PV), cc/g
Pore volume is an indication of the quantity of voids in the catalyst
particles and can be a clue in detecting the type of catalyst deactivation
that takes place in a commercial unit. Hydrothermal deactivation has
very little effect on pore volume, whereas thermal deactivation decreases
pore volume.

Pore Diameter (°A)
The average pore diameter (APD) of a catalyst can be calculated
from the E-cat analysis sheet by using the following equation:
PV x 4 x 10,000
APD(°A) =
SA
Example 3-1

2
For an E-cat with a PV = 0.40 cc/g and SA = 120 m /g, deter-
mine APD,

APD = 133 °A

Particle Size Distribution (PSD)
PSD is an important indicator of the fluidization characteristics
of the catalyst, cyclone performance, and the attrition resistance of
the catalyst. A drop in fines content indicates the loss of cyclone
efficiency. This can be confirmed by the particle size of fines collected
downstream of the cyclones. An increase in fines content of the E-cat
indicates increased catalyst attrition. This can be due to changes in
fresh catalyst binder quality, steam leaks, and/or internal mechanical
problems, such as those involving the air distributor or slide valves.

Chemical Properties

The key elements that characterize chemical composition of the catalyst
are alumina, sodium, metals, and carbon on the regenerated catalyst.

Alumina (A1 2O 3)
The alumina content of the E-cat is the total weight percent of
alumina (active and inactive) in the bulk catalyst. The alumina content