naphtha in the steam crackers and propane is being dehydrogenated. This will
further increase the percentage of propylene made from FCCUs in the United
States.
The deep catalytic cracking (DCC) process was the first commercialized FCC
process to make large amounts of propylene as seen in Table 3. Since then, all of the
major licensors have offered processes to maximize propylene.
There are two families of technologies to produce propylene in FCC type units.
The main processes use heavier feedstocks, i.e., vacuum gas oils and resids, while
several others are intended to crack naphthas or various light olefinic streams. The
commercial processes being offered are listed in Table 16 along with the feedstocks
for each.
Hydrotreating the feed enhances the light olefin yields of all of the heavy oil
technologies since increased hydrogen content is necessary to make a product with
over 14 wt% hydrogen. The naphtha processes make more propylene since the
feedstocks have a much higher percentage of propylene precursors. However,
naphtha has a higher value than the heavier feeds so these processes will see
more limited application.
Refiners have used gas oil cracking technologies to maximize propylene for
downstream petrochemical processes as well as routed the ethane and ethylene
from the cat cracker to an adjacent steam cracker gas plant for recovery. This means
that C 2 plus recovery is practiced in these FCCUs versus the normal C 3 recovery for
a fuel application. This is one of the synergies obtained by combining a refinery and
petrochemical operation. Since the propylene is made by overcracking the gasoline,
it is important to adjust the unit design, operating parameters, and catalyst formulations for best results.
The product qualities of the naphtha from the deep catalytic cracking process are
compared to a conventional FCC unit and a steam cracker in Table 17. The higher
aromatic concentration in the naphtha is mostly a result of the concentration of
existing aromatics due to the cracking of the paraffins and cycloparaffins rather than
Table 16 Heavy feed and naphtha propylene processes
Process
Licensor
Feed
Heavy feed propylene processes
DCC
Technip-Stone & Webster/RIPP
VGO and light ATB
Maxofin
Kellogg, Brown & Root
VGO and ATB
PetroFCC
UOP
VGO
Indmax
Lummus/Indian Oil
VGO and ATB
Resid FCC
Technip-Stone & Webster/Axens
ATB
Milos
Shell Global Solutions
VGO
HS-FCC
Nippon, Aramco, Technip-Stone & Webster
VGO
CPP
RIPP/Technip-Stone & Webster
VGO
Naphtha cracking processes
Superflex
Kellogg, Brown & Root
Olefinic gasoline
ACO
Kellogg/Brown & Root/Korea
Gasoline streams
Fluid Catalytic Cracking (FCC) in Petroleum Refining
299
further increase the percentage of propylene made from FCCUs in the United
States.
The deep catalytic cracking (DCC) process was the first commercialized FCC
process to make large amounts of propylene as seen in Table 3. Since then, all of the
major licensors have offered processes to maximize propylene.
There are two families of technologies to produce propylene in FCC type units.
The main processes use heavier feedstocks, i.e., vacuum gas oils and resids, while
several others are intended to crack naphthas or various light olefinic streams. The
commercial processes being offered are listed in Table 16 along with the feedstocks
for each.
Hydrotreating the feed enhances the light olefin yields of all of the heavy oil
technologies since increased hydrogen content is necessary to make a product with
over 14 wt% hydrogen. The naphtha processes make more propylene since the
feedstocks have a much higher percentage of propylene precursors. However,
naphtha has a higher value than the heavier feeds so these processes will see
more limited application.
Refiners have used gas oil cracking technologies to maximize propylene for
downstream petrochemical processes as well as routed the ethane and ethylene
from the cat cracker to an adjacent steam cracker gas plant for recovery. This means
that C 2 plus recovery is practiced in these FCCUs versus the normal C 3 recovery for
a fuel application. This is one of the synergies obtained by combining a refinery and
petrochemical operation. Since the propylene is made by overcracking the gasoline,
it is important to adjust the unit design, operating parameters, and catalyst formulations for best results.
The product qualities of the naphtha from the deep catalytic cracking process are
compared to a conventional FCC unit and a steam cracker in Table 17. The higher
aromatic concentration in the naphtha is mostly a result of the concentration of
existing aromatics due to the cracking of the paraffins and cycloparaffins rather than
Table 16 Heavy feed and naphtha propylene processes
Process
Licensor
Feed
Heavy feed propylene processes
DCC
Technip-Stone & Webster/RIPP
VGO and light ATB
Maxofin
Kellogg, Brown & Root
VGO and ATB
PetroFCC
UOP
VGO
Indmax
Lummus/Indian Oil
VGO and ATB
Resid FCC
Technip-Stone & Webster/Axens
ATB
Milos
Shell Global Solutions
VGO
HS-FCC
Nippon, Aramco, Technip-Stone & Webster
VGO
CPP
RIPP/Technip-Stone & Webster
VGO
Naphtha cracking processes
Superflex
Kellogg, Brown & Root
Olefinic gasoline
ACO
Kellogg/Brown & Root/Korea
Gasoline streams
Fluid Catalytic Cracking (FCC) in Petroleum Refining
299