Page 110 - Fluid Catalytic Cracking Handbook

FCC Catalysts 8?

Table 3-1
Properties of Major Synthetic Zeolites

Pore Size Silica-to-
Zeoiite Dimensions Alumina
Type (°A) Ratio Applications
Zeolite A 4.1 2-5 Detergent manufacturing
Faujasite 7.4 3-6 Catalytic cracking and hydrocracking
ZSM-5 5.2 x 5.8 30-200 Xylene isomerization, benzene
alkylation, catalytic cracking,
catalyst dewaxing, and methanol
conversion.
Mordenite 6.7 x 7.0 10-12 Hydro-isomerization, dewaxing

stability than the Y zeolite. Some of the earlier FCC zeolite catalysts
contained X zeolite; however, virtually all of today's catalysts contain
Y zeolite or variations thereof (Figure 3-2).
ZSM-5 is a versatile zeolite that increases olefin yields and octane.
Its application is further discussed later in this chapter.
Until the late 1970s, the NaY zeolite was mostly ion exchanged with
rare earth components. Rare earth components, such as lanthanum and

USY Zeolite (~ 7 Al Atoms/u.c.) Equilibrium REY (-23 Al Atoms/u.c.)
Unit Cell Dimension =24.25 A (SiO 2/AI 2O 3=54) Unit Cell Dimension = 24.39 A (SiO 2/AI 2O 3 « 15)
Figure 3-2. Geometry of USY and REY zeolites [14].