PROCESS FOR FLUID CATALYTIC CRACKING OF HEAVY OIL
Technical Field
[0001] The present invention relates to a process
for fluid catalytic cracking of a heavy oil,
specifically to a fluid catalytic cracking process to
produce light olefins such as propylene, butene or the
like from a heavy oil at a high yield.
Background Art
[0002] In a conventional fluid catalytic cracking
process, petroleum-derived hydrocarbons are
catalytically cracked with a catalyst to produce
gasoline as the main product, a small amount of LPG and
a cracked gas oil, and coke deposited on the catalyst
is then burnt off with air to regenerate and recycle
the catalyst.
In recent years, however, there has been a
tendency to use a fluid catalytic cracking unit as a
unit for producing light olefins (particularly
propylene) for use as petrochemical raw materials not
as a unit for producing gasoline. Whilst, propylene,
butene and the like are raw materials of alkylate and
methyl-t-butyl ether (MTBE) that are high-octane
gasoline blending stocks. Such utilization of a fluid
catalytic cracking unit for producing olefins is
-1economically
advantageous particularly to an oil
refinery where a petroleum refining facility and a
petrochemical facility are highly closely combined.
Examples of methods for producing light
olefins by fluid catalytic cracking of a heavy oil
include those comprising contacting a feedstock with
a catalyst for a shortened period of time (Patent
Literatures 1 to 4), that comprising carrying out a
cracking reaction at elevated temperatures (Patent
Literature 5), and those comprising using pentasyl type
zeolites (Patent Literatures 6 and 7).
[0003] However, these methods cannot still be
enhanced in light olefin selectivity sufficiently.
For example, the methods where cracking is carried out
at elevated temperatures accompany thermal cracking of
a heavy oil, resulting in an increase in the unnecessary
dry gas yield and thus sacrifice the yield of useful
light olefins. Furthermore, the reaction at elevated
temperatures increases the production of diene and thus
has a drawback that the gasoline produced together with
light olefins would be poor in quality. The method
where the reaction is carried out for a shortened
contact time can suppress a hydrogen transfer reaction
and thus decrease the conversion rate of light ole fins
to light paraffins but is still insufficient in the
-2yield
of light olefins because it cannot enhance the
conversion rate of a heavy oil to light olefins.
Alternatively, a method has been proposed, in which the
techniques such as those involving an elevated
temperature reaction, a higher catalyst/oil ratio and
a shortened contact time are combined to suppress
thermal cracking and still achieve a high conversion
rate to olefins (Patent Literature 8), but the light
olefin yield cannot be deemed sufficient. The methods
using a pentasyl type zeolite only enhance the yield
of light olefins by excessively cracking the resulting
gasoline and thus have drawbacks that the light olefin
yield is not sufficient and the gasoline yield is
significantly decreased. It is, therefore, difficult
to produce light ole fins at a high yield from a heavy
oil with these methods.
A method has been proposed in which in
addition to the elevated temperature reaction, higher
catalyst/oil ratio, and shortened contact time, the
reaction zone is a downflow type reaction zone that
suppresses back mixing of a feedstock and the content
of a rare-earth metal oxide in a fluid catalytic
cracking catalyst and the mix ratio of an additive
containing a shape selectivity zeolite are adjusted to
further enhance the light olefin yield (Patent
3Literature
9). However, when the fluid catalytic
cracking catalyst is insufficient in activity, these
methods lack in cracking of a heavy feedstock and thus
have not achieved the maximization of the light olefin
yield.
Citation List
Patent Literature
[0004] Patent Literature 1 : U.S. Patent No.
4,419,221
Patent Literature 2 : U . S . Patent No.
3,074,878
Patent Literature 3 : U . S . Patent No.
5,462,652
Patent Literature 4: Europe Patent No.
315,179A
Patent Literature 5: U.S. Patent No.
4,980,053
Patent Literature 6: U.S. Patent No.
5,326,465
Patent Literature 7: Japanese Patent
Laid-Open Translation No. 7-506389
Patent Literature 8: Japanese Patent
Application Laid-Open Publication No. 10-60453
Patent Literature 9: Japanese Patent No.
3948905
-4Summary
of Invention
Technical Problem
[0005] The present invention has an object to
provide a process for fluid catalytic cracking of heavy
oil which can produce light olefins at a high yield and
decrease the amount of dry gas generated by thermal
cracking with a specific combination of a reaction mode,
reaction conditions, a catalyst and the like.
Solution to Problem
[0006] As the results of extensive studies focusing
on the production of light ole fins at a high yield in
a process for fluid catalytic cracking of a heavy oil
by contacting the oil with a catalyst at an elevated
temperature for a short period of time to produce light
ole fins such as propylene and butene, the present
invention has been accomplished on the basis of the
finding that the above object is achieved by fluid
catalytic cracking of a heavy oil using a catalyst
containing a specific fluid catalytic cracking
catalyst under specific conditions.
[0007] That is, the present invention relates to a
process for fluid catalytic cracking of a heavy oil to
produce light olefins, comprising contacting the heavy
oil with a catalyst comprising as a constituent thereof
a fluid catalytic cracking catalyst with a weight ratio
(Wmat/Wusy) of an active matrix weight (Wmat) to an
ultrastable Y type zeolite weight (Wusy) of 0 to 0.3,
under conditions where the reaction zone outlet
temperature is from 580 to 630°C, the catalyst/oil
ratio is from 15 to 40 weight/weight and the residence
time of hydrocarbon in the reaction zone is from 0.1
to 1.0 second.
[0008] The present invention also relates to the
foregoing process for fluid-catalytic cracking of
heavy oil wherein the catalyst comprises 50 to 95
percent by mass of the fluid catalytic cracking
catalyst and 5 to 50 percent by mass of an additive
comprising a shape selectivity zeolite.
The present invention also relates to the
foregoing process for fluid-catalytic cracking of
heavy oil wherein the content of the ultrastable Y type
zeolite in the fluid catalytic cracking catalyst is
from 5 to 50 percent by mass.
The present invention also relates to the
foregoing process for fluid-catalytic cracking of
heavy oil wherein the ultrastable Y type zeolite has
a crystal lattice constant of 24.20 to 24.60A.
The present invention also relates to the
foregoing process for fluid-catalytic cracking of
heavy oil wherein the content of a rare-earth metal
-6oxide
in the fluid catalytic cracking catalyst is 1.5
percent by mass or less.
The present invention also relates to the
foregoing process for fluid-catalytic cracking of
heavy oil wherein a fluid catalytic cracking reactor
having a downflow type reaction zone, a gas-solid
separation zone, a stripping zone and a catalyst
regeneration zone is used.
Advantageous Effect of Invention
[0009] The present invention can produce light
olefins such as propylene and butene at a high yield
with a less amount of dry gas generated by thermal
cracking.
Brief Description of Drawing
[0010] FIG. 1 shows an example of a fluid catalytic
cracking reactor having a downflow type reaction zone,
a gas-solid separation zone, a stripping zone and a
catalyst regeneration zone.
Description of Embodiments
[0011] The present invention will be described in
detail below.
[0012] The present invention is a process for fluid
catalytic cracking of heavy oil to produce light
olefins. In the present invention, fluid catalytic
cracking is referred to as a process wherein a heavy
-7oil
is continuously brought into contact with a
catalyst that is maintained in a fluidized state to be
cracked to light ole fins and light hydrocarbons mainly
composed of gasoline.
[0013] The fluid catalytic cracking unit used
herein may be a fluid catalytic cracking unit having
a reaction zone, a gas-solid separation zone, a
stripping zone and a catalyst regeneration zone.
[0014] The reaction zone may be, for example, a
so-called riser reaction zone wherein both catalyst
particles and a feedstock ascend through a pipe or a
downflow type (downer) reaction zone wherein both
catalyst particles and a feedstock descend through a
pipe.
However, when a usual riser reaction zone is
used, back mixing may occur, causing locally a long
residence time of gas and thus thermal cracking could
be accompanied. In particular, when the catalyst/oil
ratio is extremely larger than that of a usual fluid
catalytic cracking process, like the present invention,
the scale of back mixing becomes large. Thermal
cracking is not preferable be.cause it inr:;:reasesthe
. .
amount of unnecessary generated dry gas and decrease
the yields of the intended light olefins and gasoline.
A downflow type (downer) reaction zone wherein both
-8catalyst
particles and a feedstock descend through a
pipe is, therefore, preferably used in the present
invention.
[0015] The cracked reaction mixture comprising a
mixture of a cracked reaction product having been
subjected to fluid catalytic cracking in the reaction
zone, an unreacted product and the used catalyst is then
forwarded to a gas-solid separation zone, in which most
of the hydrocarbons comprising the cracked reaction
product and un reacted product are removed from the
catalyst particles. If necessary, the cracked
reaction mixture is quenched immediately upstream or
immediately downstream of the gas-solid separation
zone so as to suppress unnecessary thermal cracking or
excessive cracking.
[0016] The used catalyst from which most of the
hydrocarbons have been removed is then forwarded to the
stripping zone to remove the hydrocarbons that have not
been removed in the gas-solid separation zone using gas
for stripping. After the used catalyst and
of heavy hydrocarbons deposited thereon is forwarded
from the stripping zone to the catalyst regeneration
zone to regenerate the used catalyst. In the catalyst
-9regeneration
zone, the used catalyst is regenerated by
being subjected to oxidation to remove the carbonaceous
material and heavy hydrocarbons deposited and adhered
on the catalyst. The catalyst having been regenerated
by oxidation is again forwarded to the reaction zone
and continuously recycled thereto.
[0017] FIG. 1 shows an example of a fluid catalytic
cracking reactor having a downflow mode reaction zone,
a gas-solid separation zone, a stripping zone and a
catalyst regeneration zone. The present invention
will be described with reference to FIG. 1 below.
[0018] A heavy oil that is a feedstock is supplied
through a line 10 to a mixing area 7, in which it is
mixed with a regenerated catalyst recycled from a
catalyst reservoir 6. The mixture flows co-currently
down through a reaction zone 1, during which the feed
heavy oil and the catalyst contact each other at an
elevated temperature for a short period of time so as
to crack the heavy oil. The cracked reaction mixture
flows from the reaction zone 1 downwardly to a gas-solid
separation zone 2 located below the reaction zone 1,
in which the used catalyst is separated from the cracked
reaction product and unreacted materials and then led
through a dipleg 9 to an upper portion of a stripping
zone 3.
-10[
0019] Hydrocarbon gas from which a majority of the
used catalyst have been removed is then led to a
secondary separator 8. In this separator, a slight
amount of the used catalyst remaining in the
hydrocarbon gas is removed, and the hydrocarbon gas is
extracted out of the system to be recovered. The
secondary separator 8 is preferably a tangential
cyclone.
[0020] The used catalyst in the stripping zone 3 is
brought into contact with gas for stripping introduced
from a line 11 to remove hydrocarbons deposited and
remaining on and between the catalyst particles. The
stripping gas may be an inert gas such as steam generated
from a boiler and nitrogen pressurized with a
compressor.
[0021] The stripping conditions are usually those
including a temperature of 500 to 900°C, preferably 500
to 700°C and a residence time of the catalyst particles
of 1 to 10 minutes. In the stripping zone 3, the cracked
reaction products and unreacted materials deposited
and remaining on the used catalyst are removed and
extracted out of the stripping zone 3 through a line
12 extending from the top thereof together with the
stripping gas to be led to a recovery system. Whilst,
the used catalyst having been stripped is fed to the
-11catalyst
regeneration zone 4 through a line provided
with a first flow rate regulator 13.
[0022] The gas superficial velocity in the
stripping zone 3 is usually maintained in the range of
preferably 0.05 to 0.4 mis, thereby forming the
fluidized bed in the stripping zone into a bubbling
fluidized bed. A bubbling fluidized bed is relatively
slow in gas velocity and thus can decrease the
consumption of stripping gas and is relatively large
in bed density and thus can significantly extend the
pressure control range of the first flow rate regulator
13, resulting in easy transfer of the catalyst
particles from the stripping zone 3 to the catalyst
regeneration zone 4. The stripping zone 3 may be
provided with horizontal porous plates or other inserts
disposed in a multi-step manner so as to make a good
contact between the used catalyst and the stripping gas
thereby improving the stripping efficiency.
[0023] The catalyst regeneration zone 4 is
segmented to an upper conical section and a lower
cylindrical vessel section, the upper conical section
being communicated with an upright tube (riser type
regenerator) 5. Preferably, the catalyst
regeneration zone 4 has an upper conical section with
an apex angle of usually 30 to 90 degrees and a height
-12of
1/2 to 2 times of the diameter of the lower
cylindrical section. While the used catalyst supplied
from the stripping zone 3 to the catalyst regeneration
zone 4 is fluidized with regeneration gas (typically
air such as oxygen-containing gas) introduced from the
bottom thereof, it is regenerated by burning off
substantially all of the carbonaceous materials and
heavy hydrocarbons deposi ted on the catalyst surfaces.
The regeneration conditions are usually those
including a temperature of 600 to 1000°C, preferably
650 to 750°C, a catalyst residence time of 1 to 5 minutes
and a gas superficial veloci ty of preferably 0.4 to 1.2
m/s.
[0024] The regenerated catalyst regenerated in the
regeneration zone 4 and flying out from an upper portion
of a turbulent fluid bed is transferred from the upper
conical section to a riser type regenerator 5 by being
accompanied wi th the used regeneration gas. The riser
type regenerator 5 communicating with the upper conical
section of the catalyst regenera
tion zone 4 has a diameter that is preferably 1/6 to
1/3 of the diameter of the lower cylindrical portion.
Whereby, the gas superficial velocity of the fluidized
bed in the catalyst regeneration zone 4 can be kept to
be in the range of 0.4 to 1.2 mls that is suitable for
-13the
formation of turbulent fluidized bed and the gas
superficial velocity of the riser type regenerator 5
can be kept to be in the range of 4 to 12 mls that is
suitable for transferring upwardly the regenerated
catalyst.
[0025] The regenerated catalyst ascending through
the riser type regenerator 5 is conveyed to a catalyst
reservoir 6 disposed on the top of the riser type
regenerator. The catalyst reservoir 6 also functions
as a gas-solid separator, in which the used
regeneration gas containing carbon dioxide is
separated from the regenerated catalyst and discharged
through the cyclone 15 out of the system.
[0026] Whilst, the regenerated catalyst in the
catalyst reservoir 6 is supplied to a mixing area 7
through a downward flow pipe provided with a second flow
rate regulator 17. If necessary, for the easy control
of the catalyst circulation rate in the riser type
regenerator 5, the regenerated catalyst in the catalyst
reservoir 6 may be partially returned to the catalyst
regeneration zone 4 via a bypass conduit provided with
a third flow rate regulator 16. In this manner, e
catalyst is circulated in the system in the order ~f
the downflow type reaction zone 1, the gas-solid
separation zone 2, the stripping zone 3, the catalyst
-14regeneration
zone 4, the riser type regenerator 5, the
catalyst reservoir 6 and the mixing area 7 and again
the downflow type reaction zone 1.
[0027] Examples of the heavy oil used in the present
invention include a vacuum gas oil, an atmospheric
residue, a vacuum residue, a thermal cracked gas oil
and a heavy oil produced by hydrorefining any of these
oils. These heavy oils may be used alone or in
combination or may be a mixture of any of these heavy
oil and a minor portion of a light oil.
The heavy oil used as the feedstock has
distillation characteristics of a boiling point range
of preferably 170 to 800 D e, more preferably 190 to
780 D e.
[0028] The "reaction zone outlet temperature"
referred herein is an outlet temperature of the
reaction zone and is a temperature immediately before
separation of the cracked reaction product from the
ca ta 1 y s tor immedi ate 1 y be f ore quench ing the reo f in the
case where they are quenched immediately upstream of
the gas-solid separation zone. The reaction zone
outlet temperature in the present invention is in a
range of 580 to 630 D e, preferably 590 to 620 D e. I f the
temperature is lower than 580 D e, light olefins will not
be produced at a high yield while if the temperature
-15is
higher than 630°C, thermal cracking will occur
remarkably, causing an increase in the amount of
generated dry gas.
[0029] The catalyst/oil ratio referred herein is a
ratio of the catalyst circulation rate (ton/h) and the
feedstock feeding rate (ton/h). In the present
invention, the catalyst/oil ratio is necessarily 15 to
40 weight/weight, preferably 20 to 30 weight/weight.
If the catalyst/oil ratio is smaller than 15
weight/weight, the temperature of the regenerated
catalyst to be supplied to the reaction zone will be
increased due to the heat balance, causing an increase
in the amount of dry gas generated by thermal cracking.
If the catalyst/oil ratio is greater than 40
weight/weight, the catalyst circulation rate will
increase and thus the capacity of the catalyst
regeneration zone will be undesirably too large to
secure a catalyst residence time needed to regenerate
the catalyst in the catalyst regeneration zone.
[0030] The residence time of hydrocarbons referred
herein is either a time from the start of contact of
the catalyst and feedstock till the separation of the
catalyst from the resulting cracked reaction product
in the reaction zone outlet or a time from the start
of contact of the catalyst and feedstock till the
-16quenching
if the cracked reaction product is quenched
i mme d i ate I y ups t ream 0 f the gas - sol ids epa rat ion z 0 n e .
In the present invention, the residence time is
necessarily 0.1 to 1.0 second, preferably 0.2 to 0.7
second. If the residence time of hydrocarbon in the
reaction zone is shorter than 0.1 second, the cracking
reaction will be insufficient, resulting in a failure
to produce light olefins at a high yield. If the
residence time is longer than 1.0 second, thermal
cracking involves too much.
No particular limitation is imposed on the
operating conditions of the fluid catalytic cracking
reactor in the present invention other than those
described above, which is usually operated at a
reaction pressure of preferably 150 to 400 kPa.
[0031] The catalyst used in the present invention
comprises a fluid catalytic cracking catalyst and an
additive.
The fluid catalytic cracking catalyst
comprises an active component that is a zeolite and a
matrix that is a supporting material for the zeolite.
The main component of the zeolite is an
ultrastable Y type zeolite.
The matrix comprises an active matrix, a
binder (silica or the like), a filler (clay mineral or
-17the
like), and other components (rare-earth metal oxide,
metal trap component or the like).
The active matrix has a cracking activity and
may be alumina or silica-alumina.
[0032] When a heavy feedstock is subjected to fluid
catalytic cracking, a fluid catalytic cracking
catalyst generally contains an active matrix so as to
crack crudely the feedstock to be in such a form that
can be cracked with an ultrastable Y type zeolite, but
a catalyst with a less content of an active matrix can
obtain a higher cracking activity under the preferable
conditions for the present invention. The fluid
catalytic cracking catalyst of the present invention
has a ratio of (Wmat/Wusy) of an active matrix weight
(Wmat) to an ultrastable Y type zeolite weight (Wusy)
in the range of necessarily 0 to 0.3, preferably 0 to
o.28 .
If the ratio of (Wmat/Wusy) of an active
matrix weight (Wmat) to an ultrastable Y type zeolite
weight (Wusy) exceeds 0.3, the cracking rate of a heavy
oil tends to be reduced, and the coke selectivity
relative to the cracking rate will be high, resulting
a decrease in the yield of light olefins.
[0033] The content of the rare-earth metal oxide in
the fluid catalytic cracking catalyst is preferably 1.5
-18percent
by mass or less, more preferably 1.2 percent
by mass or less, particularly preferably 1.0 percent
by mass or less. If the content of the rare-earth metal
oxide in the fluid catalytic cracking catalyst is more
than 1.5 percent by mass, the resulting catalyst will
be too high in hydrogen transfer activity and thus be
decreased in the yield of light olefins though be high
in cracking activity.
[0034] In general, the more the content of the rare
earth oxide in the fluid catalytic cracking catalyst
is, the higher the heat resistance is, and the higher
the equilibrium catalyst activity is. Whilst, an
equilibrium catalyst containing a large amount of a
rare-earth metal oxide will be also high in hydrogen
transfer activity. When the fluid catalytic cracking
catalyst is high in hydrogen transfer activity, the
resulting product is decreased in the amount of olefin
but increased in the amount of paraffin. Ole fins in
a gasoline fraction are mainly cracked to light olefins
with an additive containing a shape selectivity zeolite
described later. However, since the cracking rate of
paraffins in a gasoline fraction with the additive is
significantly slower that of olefins, the higher the
hydrogen transfer activity of the fluid catalytic
cracking catalyst is, the slower the production rate
-19of
light olefins with the additive is.
[0035] The ultrastable Y type zeolite has a crystal
lattice constant of preferably 24.20 to 24.60A, more
preferably 24.36 to 24.45A. Within these ranges, the
smaller that crystal lattice constant is, the lesser
the gasoline yield is but the more the light olefin yield
is. However, if the crystal lattice constant is
smaller than 24.20A, the resulting fluid catalytic
cracking catalyst is too low in cracking activity to
obtain a high conversion rate and is decreased in the
light olefin yield. If the lattice constant is larger
than 24.60A, the resulting catalyst will be too high
in hydrogen transfer activity.
The crystal lattice constant of a zeolite
referred herein is measured in accordance with ASTM
0-3942-80.
[0036] The content of the ultrastable Y type zeolite
in the fluid catalytic cracking catalyst is preferably
5 to 50 percent by mass, more preferably 15 to 40 percent
by mass. The fluid catalytic cracking catalyst
preferably has a bulk density of 0.5 to 1.0 glml, an
average particle diameter of 50 to 90 pm, a surface area
of 50 to 350 m2 Ig, and a pore volume of 0.05 to 0.5 ml/g.
[0037] The additive that is a constituent of the
catalyst used in the present invention contains a shape
-20selectivity
zeolite. Examples of constituents other
than the shape selectivity zeolite include binders
(silica or the like), fillers (clay mineral or the like)
and the like.
The shape selectivity zeolite is a zeolite
with a pore size smaller than that of the y type zeolite
so that only hydrocarbons with limited shapes can enter
the pores. Examples of such zeolites include ZSM-5,
~, omega, SAPO-5, SAPO-II, SAPO-34, and pentasil type
metallosilicate. Among these shape selectivity
zeolites, ZSM-5 is most preferably used.
[0038] The content of the shape selectivity zeolite
in the additive is preferably from 20 to 70 percent by
mass, more preferably from 30 to 60 percent by mass.
The additive has preferably a bulk density of 0.5 to
1.0 g/ml, an average particle diameter of 50 to 90 pm,
a surface area of 10 to 200 m2 /g, and a pore volume of
0.01 to 0.3 ml/g.
[0039J The ratio of the fluid catalytic cracking
catalyst and additive in the catalyst used in the
present invention is 50 to 95 percent by mass,
preferably 55 to 90 percent by mass of the fluid
catalytic cracking catalyst and 5 to 50 percent by mass,
preferably 10 to 45 percent by mass of the additive
containing a shape selectivity zeolite. If the ratio
-21of
the fluid catalytic cracking catalyst is less than
50 percent by mass, or the ratio of the additive is more
than 50 percent by mass, the conversion rate of a
feedstock that is a heavy oil will be decreased and a
higher light olefin yield cannot be obtained. Whilst,
the ratio of the fluid catalytic cracking catalyst is
more than 95 percent by mass, or the ratio of the
additive is less than 5 percent by mass, a high
conversion rate can be obtained but a higher light
olefin yield cannot be obtained.
Examples
[0040] Hereinafter, the present invention will be
described in more detail by way of the following
examples, which should not be construed as limiting the
scope of the invention.
[0041] (Example 1)
Fluid catalytic cracking of a heavy oil was
carried our using a downflow reactor (downer) type FCC
pilot unit. The scale of the device includes an
inventory of 5 kg and a feed amount of 1 kg/h while the
operation conditions include a reaction zone outlet
temperature of 600°C, a reaction pressure of 196 kPa
(1.0 kg/cm2 G), a catalyst/oil ratio of 25 weight/weight,
and a catalyst regeneration zone temperature of 720°C.
The residence time of hydrocarbon in the reactor was
20.5
second. The feedstock used in this example was a
desulfurized atmospheric residue (desulfurized AR) of
an oil produced in the Middle East (Arabian light). The
catalyst used in this example was a mixture of 75 percent
by mass of fluid catalytic cracking catalyst (A) and
25 percent by mass of an additive containing ZSM-5
(produced by Davison under the trade name of
OlefinsMax). Fluid catalytic cracking catalyst (A)
contains an active matrix and an ultrastable Y type
zeolite at a ratio (Wmat/Wusy) of the active matrix
weight (Wmat) to the ultrastable Y type zeolite weight
(Wusy) of 0 (zero), and has a crystal lattice constant
of 24.40A. Prior to being fed to the unit, fluid
catalytic cracking catalyst (A) and the additive were
separately subjected to steaming at 810°C for 6 hours
with 100% steam. The results of the cracking reaction
are set forth in Table 1.
[0042] (Example 2)
Fluid catalytic cracking of a heavy oil was
conducted under the same conditions as those of Example
1 using the same unit as that of Example 1. The
feedstock used in this example is the same as the
desulfurized atmospheric residue (desulfurized AR) of
an oil produced in the Middle East (Arabian light) used
in Example 1. Fluid catalytic cracking catalyst (B)
-23used
in this example contains an active matrix and an
u1trastab1e Y type zeolite at a ratio (Wmat/Wusy) of
the active matrix weight (Wmat) to the u1trastab1e Y
type zeolite weight (Wusy) of 0.13. The results of the
cracking reaction are set forth in Table 1.
[0043] (Example 3)
Fluid catalytic cracking of a heavy oil was
conducted under the same conditions as those of Example
1 using the same unit as that of Example 1. The
feedstock used in this example is the same as the
desu1furized atmospheric residue (desu1furized AR) of
an oil produced in the Middle East (Arabian light) used
in Example 1. Fluid catalytic cracking catalyst (C)
used in this example contains an active matrix and an
u1trastab1e Y type zeolite at a ratio (Wmat/Wusy) of
the active matrix weight (Wmat) to the u1trastab1e Y
type zeolite weight (Wusy) of 0.26, and has a rare-earth
metal oxide content of 1.50 percent by mass. The
results of the cracking reaction are set forth in Table
1 .
[0044] (Example 4)
Fluid catalytic cracking of a heavy oil was
conducted under the same conditions as those of Example
1 using the same unit as that of Example 1. The
feedstock used in this example is a desu1furized vacuum
-24gas
oil (desulfurized VGO) of the same oil produced in
the Middle East (Arabian light) used in Example 1.
Fluid catalytic cracking catalyst (A) used in this
example contains an active matrix and an ultrastable
Y type zeolite at a ratio (Wmat/Wusy) of the active
matrix weight (Wmat) to the ultrastable Y type zeolite
weight (Wusy) of 0 (zero). The results of the cracking
reaction are set forth in Table 1.
[0045] (Example 5)
Fluid catalytic cracking of a heavy oil was
conducted under the same conditions as those of Example
1 using the same unit as that of Example 1. The
feedstock used in this example is a desulfurized vacuum
gas oil (desulfurized VGO) of the same oil produced in
the Middle East (Arabian light) used in Example 1.
Fluid catalytic cracking catalyst (B) used in this
example contains an active matrix and an ultrastable
Y type zeolite at a ratio (Wmat/Wusy) of the active
matrix weight (Wmat) to the ultrastable Y type zeolite
weight (Wusy) of 0.13. The results of the cracking
reaction are set forth in Table 1.
[0046] (Example 6)
Fluid catalytic cracking of a heavy oil was
conducted under the same conditions as those of Example
1 using the same unit as that of Example 1. The
-25feedstock
used in this example is a desulfurized vacuum
gas oil (desulfurized VGO) of the same oil produced in
the Middle East (Arabian light) used in Example 1.
Fluid catalytic cracking catalyst (C) used in this
example contains an active matrix and an ultrastable
Y type zeolite at a ratio (Wmat/Wusy) of the active
matrix weight (Wmat) to the ultrastable Y type zeolite
weight (Wusy) of 0.26, and has a rare-earth metal oxide
content of 1.50 percent by mass. The results of the
cracking reaction are set forth in Table 1.
[0047] (Example 7)
Fluid catalytic cracking of a heavy oil was
carried out under the same conditions as those of
Example 2 except for using a catalyst that is a mixture
of 53 percent by mass of fluid catalytic cracking
catalyst (B) and 47 percent by mass of an additive
containing ZSM-5 (produced by Davison under the trade
name of OlefinsMax). The results of the cracking
reaction are set forth in Table 1.
[0048J (Comparative Example 1)
Fluid catalytic cracking of a heavy oil was
conducted under the same conditions as those of Example
1 using the same unit as that of Example 1. The
feedstock used in this example is the same as the
desulfurized atmospheric residue (desulfurized AR) of
-26an
oil produced in the Middle East (Arabian light) used
in Example 1. Fluid catalytic cracking catalyst (0)
used in this example contains an active matrix and an
ultrastable y type zeolite at a ratio (Wmat/Wusy) of
the active matrix weight (Wmat) to the ultrastable Y
type zeolite weight (Wusy) of 0.50, and has a rare-earth
metal oxide content of 0 (zero). The resul ts of the
cracking reaction are set forth in Table 1.
[0049] (Comparative Example 2)
Fluid catalytic cracking of a heavy oil was
conducted under the same conditions as those of Example
1 using the same unit as that of Example 1. The
feedstock used in this example is the same as the
desulfurized vacuum gas oil (desulfurized VGO) of an
oil produced in the Middle East (Arabian light) used
in Example 4. Fluid catalytic cracking catalyst (0)
used in this example contains an active matrix and an
ultrastable Y type zeolite at a ratio (Wmat/Wusy) of
the active matrix weight (Wmat) to the ultrastable Y
type zeolite weight (Wusy) of 0.50, and has a rare-earth
metal oxide content of 0 (zero). The resul ts of the
cracking reaction are set forth in Table 1.
[0050] (Comparative Example 3)
Fluid catalytic cracking of a heavy oil was
carried out using an upflow reactor (riser) type FCC
-27pilot
unit. The scale of the device includes an
inventory of 3 kg and a feed amount of lkg/h, and the
operation conditions include a reaction zone outlet
temperature of 520°C, a reaction pressure of 196 kPa
(1.0 kg/cm2 G), a catalyst/oil ratio of 5 weight/weight,
and a catalyst regeneration zone temperature of 720°C.
The residence time of hydrocarbon in this reactor was
1.5 second. The feedstock used in this example was a
desulfurized atmospheric residue (desulfurized AR) of
an oil produced in the Middle East (Arabian light). The
catalyst used this example was a mixture of 75 percent
by mass of fluid catalytic cracking catalyst (A) and
25 percent by mass of an additive containing ZSM-5
(produced by Davison under the trade name of
OlefinsMax). Fluid catalytic cracking catalyst (A)
contains an active matrix and an ultrastable Y type
zeolite at a ratio (Wmat/Wusy) of the active matrix
weight (Wmat) to the ultrastable Y type zeolite weight
(Wusy) of 0 (zero), and has a crystal lattice constant
of 24.40A. Prior to being fed to the unit, fluid
catalytic cracking catalyst (A) and the additive were
separately subjected to steaming at 810°C for 6 hours
with 100% steam. The results of the cracking reaction
are set forth in Table 1.
[0051] (Comparative Example 4)
-28Fluid
catalytic cracking of a heavy oil was
conducted under the same conditions as those of Example
3 using the same unit as that of Example 3. The
feedstock used in this example is a desulfurized
atmospheric residue (desulfurized AR) of an oil
produced in the Middle East (Arabian light) used in
Example 1. The catalyst used in this example is the
same as fluid catalytic cracking catalyst (B) used in
Example 2, which contains an active matrix and an
ultrastable Y type zeolite at a ratio (Wmat/Wusy) of
the active matrix weight (Wmat) to the ultrastable Y
type zeolite weight (Wusy) of 0.13. The results of the
cracking reaction are set forth in Table 1.
[0052] (Comparative Example 5)
Fluid catalytic cracking of a heavy oil was
carried out under the same conditions as those of
comparative Example 3 using the same unit as that of
Comparative Example 3. The feedstock used in this
example is a desulfurized atmospheric residue
(desulfurized AR) of the same oil produced in the Middle
East (Arabian light) used in Example 1. Fluid
catalytic cracking catalyst (C) used in this example
contains an active matrix and an ultrastable Y type
zeolite at a ratio (Wmat/Wusy) of the active matrix
weight (Wmat) to the ultrastable Y type zeolite weight
-29(
Wusy) of 0.26, and has a rare-earth metal oxide content
of 1.50 percent by mass. The results of the cracking
reaction are set forth in Table 1.
[0053] (Reference Example 1)
Fluid catalytic cracking of a heavy oil was
carried out under the same operation conditions as
those of Example 5 except for using an upflow reactor
(riser) type FCC pilot unit instead of the downflow
reactor (downer) type FCC pilot unit. The results are
set forth in Table 1.
Since in the riser reaction zone, the
residence time is partially extended due to the
influence of back mixing, excessive cracking of a
gasoline fraction was advanced and dry gas increased,
resulting in a decrease in the liquid yield comparing
with the results 0 Example 5 using the downer reaction
zone.
[0054]
-301-
3
!lJ
tr
I-'
(I)
l-'
W
l-'
I
Fluid catalytio catalyst
Additive
Catalyst name
Catalyat
USY zeolite
composition
Active matrix
Rare earth oxid
WmatlWuS':/
Feedatock name
r-~eQs:~st' Distillation 5% distillation
: ara erJ Ie temp.
95~ distlilation
temp.
Density (15"C)
Sulfur content
Reaction temperature
Catalyst/Oil
Residence time
Reactor mode
Cracking rate
Light olefin yield
Yield
Dry gas
Propylene
Butene
Gasoline
LCO
HCO
Coke
Example 1
mass" 75
mass II 25
Catalyst (A)
mass 51 45
mass !£ #REF!
mass" -
0
O••uifurized
AR
'c 362
"C 703
g/cm3 0.931
mass" 0.38
·c 600
wtlwt 25
sec. 0.5
Downer
mass!> 84.2
mass" 27.8
mass" 7.4
mass % 14.7
mass % 13.1
mass % 37.2
mass % 9.2
mass % 6.5
mass % 6.5
Example 2 Example 3 Example 4 Example 5
75 75 75 75
25 25 25 25
Catalyst (B) Cstaiyst (C) Catalyst (A) Catalyst (B)
40 38 45 40
5 10 #REF! 5
- 1.5 - -
0.13 0.26 0 0.13
Oesulfurized Desulfurized O.sulfurized Oesulfurized
AR AR VGO VGO
362 362 305 305
703 703 538 538
0.931 0.931 0.895 0.895
0.38 0.38 0.23 0.23
600 600 600 600
25 25 25 25
0.5 0.5 0.5 0.5
Downer Downer Downer Downer
83.7 85.7 82.4 82.2
27.6 2S.3 30.4 30.3
7.4 7.3 7.9 7.9
14.6 14.9 16.8 16.7
13.0 13.4 13.6 13.6
36.9 37.8 33.5 33.4
9.3 9.0 9.6 9.6
6.9 5.4 8.0 8.2
5.5 6.6 3.1 3.0
Example 6 Example 7
Comparative Comparative
Example 1 Example 2
75 53 75 75
25 47 25 25
Cai:liiyst(C) Catalyst (B) Catalyst (0) Catalyst (0)
3S, 40 30 30
10 5 15 15
1.5 - - -
0.26 0.13 0.50 0.50
O••uifuriz.d Desulfuriaed
VGO AR AR
305 362 362 305
538 703 703 538
0.895 0.931 0.931 0.S95
0.23 0.38 0.38 0.23
600 600 600 600
25 25 25 25
0.5 0.5 0.5 0.5
Downer Downer Downer Downer
83.0 79.0 SO.7 80.S
30.6 31.7 26.7 29.8
7.8 7.9 7.4 7.9
16.9 17.8 14.2 16.5
13.8 13.8 12.5 13.3
33.6 27.2 35.2 32.9
9.5 9.3 9.9 9.8
7.4 11.7 9.4 9.4
3.2 6.3 6.4 2.8
Comparative
Example 3
75
25
Catalyst'(Al
45
#REF! -
0
D••ulfurized
AR
362
703
0.931
0.38
520
5
1.5
Riser
55.2
10.0
6.2
4.2
5.8
32.1
17.4
27.4
5.8
Comparative Comparative
Example 4 Example 5
75 75
25 25
Catalyst (B) Catalyst (C)
40 3S
5 10
- 1.5
0.13 0.26
Desulfurizad ! Desulfurized
AR AR
362 362
703 703
0.931 0.931
0.38 0.38
520 520
5 5
1.5 1.5
I
Riser I Riser
56.3 59.9
10.1 10.8
6.2 6.2
4.2 4.4
5.9 6.3
32.9 35.7
17.3 16.9
26.4 23.2
5.8 5.9
Reference
Example 1
75
25
Catalyst (8)
40
5
-
0.13
Oesulfurized
VElO
305
538
0.895
0.23
600
25:
0.5
Riser
82.6!•
30.0!
9.6,
16.?!
13.3
32.5
9.5
7.9
S.l
Description of reference numerals
[0055] 1 down flow type reaction zones
2 gas-solid separation zone
3 stripping zone
4 catalyst regeneration zone
5 riser type regenerator
6 catalyst reservoir
7 mix zone
8 secondary separator
9 dipleg
13 first flow rate regulator
15 cyclone
16 third flow rate regulator
17 second flow rate regulator
2CLAIMS
[Claim 1] A process for fluid catalytic cracking
of a heavy oil to produce light olefins, comprising
contacting the heavy oil with a catalyst comprising as
a constituent thereof a fluid catalytic cracking
catalyst with a weight ratio (Wmat/Wusy) of an active
matrix weight (Wmat) to an ultrastable y type zeolite
weight (Wusy) of 0 to 0.3, under conditions where the
reaction zone outlet temperature is from 580 to 630°C,
the catalyst/oil ratio is from 15 to 40 weight/weight
and the residence time of hydrocarbon in the reaction
zone is from 0.1 to 1.0 second.
[Claim 2] The process for fluid-catalytic
cracking of heavy oil according to claim 1 wherein the
catalyst comprises 50 to 95 percent by mass of the fluid
catalytic cracking catalyst and 5 to 50 percent by mass
of an additive comprising a shape selectivity zeolite.
[Claim 3] The process for fluid-catalytic
cracking of heavy oil according to claim 1 or 2 wherein
the content of the ultrastable Y type zeolite in the
fluid catalytic cracking catalyst is from 5 to 50
percent by mass.
[Claim 4] The process for fluid-catalytic
cracking of heavy oil according to anyone of claims
1 to 3 wherein the ultrastable Y type zeolite has a crystal lattice constant of 24.20 to 24.60A.
[Claim 5] The process for fluid-catalytic cracking of heavy oil according to any one of claims 1 to 4 wherein the content of a rare-earth metal oxide in the fluid catalytic cracking catalytic is 1.5 percent by mass of less.
[Claim 6] The process for fluid-catalytic cracking of heavy oil according to any one of claims 1 to 5 wherein a fluid catalytic cracking reactor having a downflow type reaction zone, a gas-solid separation zone, a stripping zone and a catalytic regeneration zone is used.