71
widespread applications was developed by Argauer and Landolt [25] at Mobil Oil
Co. called ZSM-5. It was a microporous zeolite that selectively crack heavier olefinic hydrocarbons to increase the yield of propylene for petrochemical manufacture
purposes and alkylate yield to improve gasoline octane. ZSM-5 is widely used by
refiners to offset the LPG yield loss and octane loss caused by using US-Y or RE-Y.
Fig. 4 Evolution of modern FCC catalyst [89]
Dual function
metal passivator
SOx addcitive
CO promoter
Y zeolite based &
REY catalysis
High alumina
catalyst
1915
1940
First catalytic cracking AICl3
First commercial FCC, natural
clay
Nickel passivation
(Sb)
USY zeoite
Octane additive
BCA, Resid FCC,
Low RE USY &
Alumina catalyst
Light clefin
maxmizer
Additive: Octane
barrel enhancer &
Coke reduction
1950
1960
1970
1980
1990 2000
2010 2015
Nickel passivation (Bi)
Fig. 5 Evolution of FCC catalyst additives [90]
Recent Developments in FCC Process and Catalysts