Appeal No. 95-2227
Application No. 08/048,964
a. charging a heavy hydrocarbon feed comprising hydrocarbons boiling above
650°F to a riser catalytic cracking reactor;
b. charging a hot fluidized solids mixture, from a catalyst regenerator to the base of
said riser reactor, said mixture comprising:
a physical mixture of regenerated base FCC cracking catalyst and separate
particles of shape selective zeolite cracking catalyst additive, said mixture
containing 87.5 to 65 wt % base FCC catalyst and 12.5 to 35 wt % additive,
and wherein said additive comprises a catalytically effective amount of a
zeolite having a silica:alumina ratio above 12 and a Constraint Index of 1 - 12
in an amorphous support,[sic. ,];
c. catalytically cracking said feed at catalytic cracking conditions including a riser
outlet temperature of about 925 to 1050°F to produce catalytically cracked products
including ethylene, propylene, and a C5 + gasoline fraction and a spent solids mixture
comprising spent cracking catalyst and additive catalyst which are discharged from said
outlet of said riser reactor;
d. separating in a vessel containing said riser outlet a cracked product rich vapor
phase, which is withdrawn from said vessel, from a spent solids mixture rich phase
containing spent cracking catalyst and shape selective additive catalyst;
e. stripping said spent solids mixture in a stripping means at stripping conditions to
produce a stripped solids phase;
f. decoking said stripped solids phase in a catalyst regeneration means operating
at catalyst regeneration conditions to produce said hot fluidized solids mixture, which is
recycled to the base of said riser reactor, and
g. fractionating said cracked product rich vapor phase in a product fractionation
means to produce:
i. at least 44.0 wt % C5+ gasoline,
ii. at least 15 LV % propylene, and
iii. no more than 2.0 wt % ethylene and wherein more propylene is produced than
would be produced by cracking the same feed at the same conditions with the same
amount of the shape selective zeolite present in the same particle as the said base FCC
cracking catalyst.
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Last modified: November 3, 2007