Note: Descriptions are shown in the official language in which they were submitted.
3816 ~ 275
PROCESS FOR INCREASING OCTANE AND REDUCING SULFUR
CONTENT OF O-EFINIC GASOLINES
This invention relates to a process for increasing the
octane number while simultaneously reducing the sulfur content of
olefinic gasolines derived from cracking processes, specifically
catalytic cracking processes.
New regulations requiring reduction of lead in gasoline
~ill lead to the need for higher average gasoline pool octanes. In
addition, there is likely to be continued interest in reducing
sulfur oxide (SOx) emissions, especially as gasolines derived from
fluidized catalytic cracking (FCC) processes are integrated more
1~ into the unleaded gasoline pools for use in automobiles equipped
with catalytic converters.
The possibility of catalytically reforming FCC naphtha to
upgrade a gasoline pool was considered by L. A. Gerritsen,
"~atalytic Reforming of FCC Naphtha for Production of Lead-Free
1~ Gasoline", Ketjen Symposium, Amsterdam, 1984~ Such prior art
disclosed reforming a FCC naphtha fraction over a bimetallic Pt-Re
catalyst, but it was found that higher severity and increased
throughput conditions of the process resulted in a deterioration of
the cycle length of the catalyst in the reformer.
Many crystalline silicate zeolites are now known to the
prior art. However, direct reforming of olefinic gasolines derived
Fr~m catalytic cracking of gas oils leads to rapid aging of
conventional reforming catalysts due to the relatively high sulfur
content (0.05 to 0~5 wt ~) of these gasolines~ The olefinic
composition of these gasolines also leads to relatively high
hydrogen consumption and corresponding exotherm during the
'.
- :
:. . ' ' ~,
-` 3,Z~Z~S
3~16 - 2 -
desulfurization necessary prior to reforming with conventional
catalysts.
Certain hydrothermally stable catalysts, such as those
taught in U. S. Patent ~o. 3,493,519, employ an ammonium-Y
crystalline aluminosilicate which is calcined in the presence of
rapidly flowing steam. The resultant steamed produot is
base-exchanged with an ammonium salt and treated with a chelating
agent capable of combining with aluminum at pH between 7 and 9.
These aluminum-deficient catalysts are reported to exhibit
enormously high activity (alpha value).
Other treatments of synthetic faujasite (NH4Y) prepared
by ammonium ion-exchange of sodium faujasite are reported in U.S.
Patent No. 3,591,488. These steamed zeolites, after heat treatment,
are base-exchanged with cations, such as ammonium ion, and/or metal
ions selected from Groups II-A, I-B to VII-B, VIII of the Periodic
Table and rare earth ions with atomic numbers 51 to 71, such as Mg,
Ca, Sr, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, W, Re, Os, Ir, Pt, Au
and Hg ions, preferably those ions of Groups II-A, VIII and rare
earths. A final zeolite product having an alkali metal content
below about 0.5 wt ~, preferably below about 0.2 wt %, is reported.
The resultant product has a silica-to-alumina mole ratios typically
greater than 5 to 10, depending on the nature of the zeolite,
preferably greater than 20, and more preferably greater than about
50.
The problem of sulfur contamination of catalysts has been
generally recognized in the prior art, as taught, for example, in U.
~; S. Patent No. 4,456,527. However, the prior art approached the
catalyst contamination problem by employing separate sulfur removal
steps to reduce the sulfur content below 500 parts per billion
(ppb), preferably less than 250 ppb, more preferably less than 100
ppb, and most preferably less than 50 ppb.
Thus, although the prior art recognized the problems of
catalyst contamination associa-ted with high sulfur-containing
~5~
3816 ~ 3
feedstocks, none of the prior art recommendations has permitted
direct reforming of an olefinic gasoline derived from FCC or TCC
catalytic cracking of gas oils, in which rapid aging of the
reforming catalyst due to the relatively high sulfur content of
these gasolines is minimized or avoided. An object of the present
invention is therfore to provide such a reforming process.
Accordingly, the invention resides in a process for
simultaneously reducing the sulfur content and increasing the octane
number of an olefinic-containing feedstock comprising contacting
la said olefinic-containing feedstock in a single stage process with anoble metal-containing crystalline zeolite having a Constraint Index
less than 2 and a framework SiO ~A1203 molar ratio no less
than 50, under conditions sufficient to yield a product of increased
octane number with respect to the octane number of said
olèfinic-containing feedstock.
The process of the present invention is directed to the
reforming and desulfurization of olefinic gasolines derived from
orscking processes, catalytic or otherwise. Without wishing to be
limited to any set process, the description of the present invention
will be directed to primarily catalytic cracking processes. By
utilizing a noble metal-containing large pore, high
~ilica-to-alumina mole ratio zeolite-containing catalyst, the
~lefinic gasoline may be processed at high temperatures and yield a
product having increased octane number and reduced sulfur content.
Reforming
By way of definition, reforming generally means a process
of boosting the octane number of a naphtha or gasoline oil to an
octane number that is acceptable for use. For example, straight run ;
naphtha from crude oil might have an octane number of 40, too low
~a for use as a aasoline. This unacceptable characteristic may be
improved by reforming. The naphtha may also contain an unacceptable
level of sulfur, e.g., 50 parts per million (ppm), which is reduced
by reforming under conditions set forth in this invention.
3 ~ ~
816 _ 4 _ ~d~3~ S
Most of today's reforming catalysts, e.g., platinum-on-
alumina, require that the sulfur in the fuel oil be reduced to a
level of about û.2 ppm or less in order for the catalyst to
survive. Conventional reformers run at -temperatures of between 900
and lG00F (482-538C) and pressures between 100 and 500 psig
(790-3550 kPa). Hydrogen is co-fed with the naphtha in a ratio of
about 5:1. With conYentional reformers, small amounts of chlorine,
and sometimes water, are co-fed with the hydrocarbon feed in order
to keep the catalyst active.
The requirement for chlorine and for the reduction of
sulphur is disadvantageous to the reforming process. Cecause of
this, standard reforming operations cannot be used for olefinic
feeds, which are the feedstocks used in the present invention.
The present invention has a number of advantages over
conventional reforming. First, most of the reforming catalysts are
limited to feedstocks having a 350F (177C) end point in the
naphtha feedstock. Any feedstock higher than the 350F (177C) end
point will tend to age the catalyst too rapidly. However, the
~present catalyst may tolerate much higher end point feedstocks.
Secondly,~there is nn requirement to pass chlorine over the catalyst
in order to keep the catalyst active, as the zeolite~of the present
invention provides the acidity needed for the reaction to take
place. Third, there is no requirement to reduce the sulphur content
by a pre-hydrotreatment step, as the use of the catalyst of the
present invention under conventional reforming conditions both
removes sulphur and raises the octane number of the feedstock
product.
Feedstock
The feedstock for the present invention is qenerally a
aasoline derived from catalytic cracking or thermocrackinq. The
catalytic cracking process may be either a fluid catalytic crackin~
(FCC) process or a thermofor catalytic crackino (TCC) process. The
feed stock may contain sulphur in concentrations greater than about
3816 - 5 ~ lZ~S27~;
1~0 ppm, which normally would have to be reduced by hydrotreatment
in order to allow the feed to be processed over a conventional
reforming catalyst. Further, the feedstock contains olefins, which
additionally would require hydrotreatment in order to be passed over
a conventional reforming catalyst. Further still, the feedstock for
the present invention may have a boiling range which exceeds the
boiling range of feedstocks conventionally processed over
conventional reforming catalysts.
~at-alysts
1~ The catalysts used in the process of the invention are
larg~ pore 2eolites having a Constraint Index less than 2 and a
framework silica-to-alumina mole ratio of at least 50:1 and
preferably greater than about 500:1. Constraint Index is a
c~nvenient measure of the extent to which a zeolite provides control
1~ to molecules of varying sizes to its internal structure. Zeolites
~hich provide a highly restricted access to and egress from its
internal structure have a high value for the Constraint Index, and
~eolites of this kind usually have pores of small size, e.g., less
than S Angstroms On the other hand, zeolites which provide
r~latively free access to the internal zeolite structure have a low
v~lue for the Constraint Index and usually pores of large size,
i.e., greater than 8 Angstroms. The method by which Constraint
Index is determined is described fully in U. S. Patent No. 4,016,218.
Zeolites having a Constraint Index less than 2 are well
~n~n in the art and generally have a pore size in excess of 7
AngstomJ that is sufficiently large to admit the vast majority of
~mponents normally found in a feed chargestock. Suitable large
pore zeolites for use in the present process are Zeolite Beta,
7e~1ite L, Zeolite Y (e.g. Ultrastable Y and nealuminized Y),
~nrdenite, ZSM-3, ZS~-4, ZSM-l~ and ZSM-20.
3816 - 6 ~ 75
Constraint Index (CI) values for representative large pore
zeolites are:
CI (At Test Temperature)
ZSM-4 0.5 (316C)
ZSM-20 0.5 (371C)
Mordenite 0.5 (316C)
Dealuminized Y (Deal Y) 0.5 (510C)
~eolite Beta 0.6-2 (316-399C)
a
Constraint Index seems to vary somewhat with severity of
operation (conversion) and the presence or absence of binders.
~ikewise, other variables, such as crystal size of the zeolite, the
presence of occluded contaminants, etc., may affect the Constraint
1~ Index. Therefore, it will be appreciated that it may be possible to
~o select test conditions, e.g., temperatures, as to establish more
than one value for the Constraint Index of a particular zeolite.
This explains the range of Constraint Indices for Zeolite Beta.
Preferred zeolites for use in the present process are
2~ Zeolite ZSM-4 (described in U. S. Patent No. 3,923,639), Zeolite
ZSM-20 (described in U. S. Patent No. 3,972,983), Zeolite Beta
~described in U. S. Patent No. 3,308,069 and Re. 28,341), Zeolite Y
(described in U. S. Patent No. 3,130,007) and modified forms of
~eolite Y such as Ultrastable Y zeolite (describe~ in U. S. Patent
7~ Nos. 3,293,192 and 3,449,070), dealuminized Y zeolite (U. S. Patent
No. 3,q42,795), and Zeolite UHP-Y (described in U. S. Patent No.
4,401,556). The most preferred zeolite is a zeolite Y which may be
treated by known methods, by steamina and/or acid dealumination7 to
raise its silica/alumina ratio to at least 50:1.
In practicing the process of the present invention, it may
be useful to incorporate the above-described crystalline zeolites
with a matrix comprising another material resistant to the
te~perature and other conditions employed in the process. Such
matrix material is useful as a binder.
3~ Useful matrix materials include both synthetic and
naturally-occurring substances, as well as inorganic materials such
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.
s ,. . .
3816 - 7 - ~29~ 75
as clay, silica and/or metal oxides. The latter may be either
naturally-occurring or in the form of ~elatinous precipitates or
gels including mixtures of silica and metal oxides.
Naturally-occurring clays which can be composited with the zeolite
include those of the montmorillonite and kaolin families, which
families include the sub-bentonites and the kaolins commonly known
as Dixie, McNamee-Georgia and Florida clays or others in which the
main mineral constituent is haloysite, kaolinite, dickite, nacrite
or anauxite. Such clays can be used in the raw state as originally
mined or initially subjected to calcination, acid treatment or
chemical modification.
In addition to the foregoing materials, the zeolites
employe~ herein may be composited with a porous matrix material,
~uch as alumina, silica, silica-alumina, silica-magnesia,
l3 silica-zirconia, silica-thoria, silica-beryllia, and silica-titania,
as well as ternary compositions, such as silica-alumina-thoria~
~ a-alumina-zirconia, silica-alumina-magnesia and
silica-magnesia-zirconia. The matrix may be in the form of a cogel.
The relative proportions of zeolite component and inorganic oxide
~a oel matrix, on an anhydrous basis, may vary widely with the zeolite
oontent ranginq from between 1 to 99 wt ~, and more usually in the
ran~e ~f 5 to 80 wt ~ of the dry composite.
The original cations associated with each of the
crystalline zeolites utilized herein may be replaced by a wide
23 vari~ty of other cations, according to techniques well known in the
art. Typical replacing cations including hydrogen, ammonium, alkyl
ammonium and metal cations, including mixtures of the same.
The crystalline zeolite utilized in the process of this
invention is employed in intimate combination with a noble metal,
ch as platinum or platinum in combination with other Group VIII
metals, e.g., platinum-rhenium or platinum-iridium, in an amount
~etween 0.1 and 25 wt ', normally 0~1 to 5 wt ~, and preferably 0~3
to 3 wt ~. Cuch component can be exchanoed into the composition,
3816 - 8 - ~Z9sz75
impregnated thereon, or physically intimately admixed therewith.
Such component can be impregnated into or onto the zeolite, such as,
for example, in the case of platinum, by treating the zeolite with a
platinum metal-containing ion. Thus, suitable platinum compounds
include chloroplatinic acid, platinous chloride and various
Compounds containing the platinum amine complex.
Process Conditions
The present process is essentially a reforming process, in
that the reactions which take place are reforming reactions.
~bwever, the process cannot be called a reforming process per se
1~ ~ince it passes an olefinic-containing feed at a high temperature
over the catalyst and directly cyclizes the olefins to aromatics.
~dditionally, the process increases the octane value and reduces the
~ulfur content of the olefinic-containing feedstock. Thus, unlike
conventional reforming processes, the process of the present
13 invention (1) accepts olefinic-containing feedstocks, (2) accepts
sulfur-containing feedstocks, and (3) accepts feedstocks with a high
~oilin~ point, i.e., in excess of 35ûF (177C).
The feedstock is contacted with the catalyst in the
presence of hydrogen under conditions of temperature, pressure,
~d space velocity and hydrogen ratio similar to those used in
~onventional reforming processes. Typical conditions include
temperatures of 600 to 1200F (300-650C), more commonly 70û to
l~nF (370-54ûC), pressures from mildly superatmospheric up to
1~35 psig (10000 kPa), more commonly 100 to 500 psig (790 to 3550
~Pa~, space velocities from 0.1 to 20 LHSV, more commonly 2-16 LHSV,
and hydrogen circulation rate of about 1125 to 5620 SCF/bbl (20û to
lOC0 Nm /m ).
The process may be conveniently operated in conventional
enu~pment, i.e., in a series of reactors with inter-staae heating to
3~ ~aintain the desired reactions and heat balance. ~s noted
previously, a particular advantaae of the use of the high siliceous
~eolite supports is that the need for acidity maintenance by
,
3816 _ 9 _ l~5Z75
chlorination, use of water co-feed and the like is substantially
reduced and may, in favorable circumstances, be eliminated.
Nonetheless, if experience demonstrates that the use of these
conventional expedients is necessary or desirable, resort may be
made to them. Thus, water may be fed in with the feedstock in
conventional amounts, typically of 1 to 100 ppm, or halogenation may
be used to maintain activity, for example, by incorporation of-the
halogen in the form of an acid or a salt or by addition of the
halagen or halide compound during the reforming process itself, in a
1~ c~nventiZonal manner. Chlorine is the preferred halogen. Details of
the halogen activity maintenance methods may be found in U. S.
P~tent N~s. 4,261,810; 4,049,539; 3,835,063; 6,661,768; and
3,~49,5~4.
The invention is illustrated by the following examples, in
1~ which all parts, proportions and percentages are by weight, unless
stated to the contrary.
Example 1
The catalyst used was prepared by steaming and acid
~ealumination of a Linde Ultrastable Y, followed by impregnation
with platinum as the tetraamine.
The resultant dealuminized Y zeolite was analyzed and found
to have a bulk SiO2/A1203 ratio of 45, with an approximate
framework, i.e., tetrahedral alumina, SiO2/A1203 of 2600 by
~AS NMR. The activity represented by the alpha value of this
material was determined to be 1.5, in good agreement with the
flpproximate frameworl< aluminum content. The platinum loading was
~t~rmined to be 0.48% and had a substantially uniform dispersion of
~, as determined by hydrogen chemisorption.
An olefinic gasoline sample from FCC of Arab Light VGO,
with a RON~û of 91 and 295n ppm sulfur, was distilled into three
fractions and analyzed for octane number (RON) and sulfur. The
~nalyses indicated that sulfur increased significantly with
increasing boiling point, while the octane number decreased, 3S
shown below.
3816 - 10 -
~;~95~75
TABLE 1
FCC Gasoline Properties
Boiling Range, F Full-Range C5-180 180-300 300-420
(C) (C5-82) (82-149) (149-216)
Yield; Wt ~ 100.0 41.0 34.3 24.3
RON+O 91.0 93.8 89.3 89.0
~ulfur, ppmw 2950 480 1850 7800
tydro~en, Wt ~ 12.6 14.0 12.7 11.4
1 Research Octane Number
1~
The intermediate ~oiling range fraction (180-300F) was
used as the feed for the process of this Example. Additional
13 analyses indicated that this fraction was composed of 17% paraffins,
4~% olefins, and 27% aromatics by weight. Process conditions of
900F (4~2C), 250 psig (1825kPa), 4.0 LHSV and about 4000 SCF/bbl
~712Nm3/m3) hydrogen flow were used to simultaneously
de~ulfuri~e and increase the octane rating of the olefinic FCC
s~line. For eighteen days prior to charging the FCC gasoline
fraction, the dealuminized Y zeolite catalyst of the invention was~
used for reforming a number of conventional feeds.
Initial results showed that about 83 wt % yield of 99 RON+O
~a~oline was obtained when processing the intermediate fraction at
th~ above conditions. Analysis showed the product to be composed of
~5~ paraf~ins, 0~ olefins, 2% naphthenes, and 73% aromatics. At
~hi~ reaction severity, it was estimated that there was a nèt
hydro~en prcductlon of about 150 SCF/bbl (~7Nm /m3). The
~r~duct compnsitions and properties can be found in Table 2.
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3816 ~ 29~275
TABLE 2
Product Compositions and Properties
Feed Product
Octane, RON + 089.3 98.6
Sulfur, ppmw 1850
Paraffins, ~t % 17 25
~lefins 44 0
Naphthenes 12 2
Aromatics 27 73
Essentially no catalyst aging was observed during six days
of additional processing of the sulfur-containing, olefinic FCC
gasoline feed.
1~ Comparing the yield and octane data suggests that similar
overall results can be achieved directly by processing with the
novel dealuminized Y zeolite catalyst of this invention, as can be
obtained by conventional hydrotreating (HDT) followed by
conventional reforming. In addition, the relatively low hydrogen
content of the olefinic FCC gasolines suggest that the net endotherm
encountered in conventional reforming could be reduced.
Example 2
The catalyst utilized in Example 2 was the same catalyst as
in ~xample 1. The feedstock for Example 2 was FCC gasoline which
was distilled and cut at 180F (82C) and 300F (149C). A complete
analysis of the full range FCC gasoline and of the cuts is given in
Table 3.
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.:
3816 - 12 -
~29~:7~
TARLE 3
Analysis of FCC Gasoline
Cut 1 Cut 2 Cut 3
Fraction (As Cut) Full-Range 180F 180-300F 300F+
(82C) 82-149C)(149C~)
Y~eld, Vol. %100.0 39.0 40.2 20.8
API Gravity 54-7 77.8 50.6 31.0
~ydro~en, Wt ~13.14 15.08 12.99 11.21
Sul~ur, ppmw 3000 400 2100 8400
Nltrogen, ppmw60 12 37 160
Para~fins1 Wt ~ 31.9 43.5 30.6 19.3
~le~ins 22.8 29.2 16.3 8.4
Naphthenes 14.7 16.1 15.8 10.6
Aromatics 30-5 11. 3 37.3 61.4
13
fiON+0 89.9 92.5 88.0 90.0
M~N+ol 79.7 80.5 __ __
RVP~ 5.15 11. 22 -- --
TBP, F
76 77 150 315
50~ 247 136 261 393
~5~ 446 236 362 488
Motor Octane Number
Reid Vapor Pressure
,
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3816 - 13 - ~29~75
It is worth noting that cut 2 and cut 3 contain significant
amounts of olefins (16% and 8%, respectively) and aromatics (37% and
61%, respectively). As a result, their octane is already high (88
and 90 RON~O). However, upon hydrotreating to remove the sulfur and
nitrogen, the octane would drop considerably. Thus, the purpose of
the present example is to find a way to maintain or even increase
the level of octane while removing the sulfur and nitrogen.
At the beginning of the run, the catalyst was heated to
30n~F ~149C) under hydrogen atmosphere, kept at that temperature
~or 2 hours, and then slowly heated to 660F (349C) at a rate of
90F (50C) per hour. The feed was started after the catalyst had
been at 660F (349C) for 2 hours. The temperature was then
increased to the desired reaction temperature. The FCC gasoline
heart cut (cut 2) was then added and maintained on-stream for 3
~eeks at a temperature of 900F (482C). The feed was then changed
1~ to the heavy FCC gasoline fraction (cut 3) for a period of 2 weeks.
Although the fractions were processed separately, it is believed
that the fractions may be co processed. The light olefinic
fraction, ~hich already had a hiah octane rating (92.5 RON) and a
relatively low sulfur content (0.04 wt %)~ did not appear to need
a further upgrading, although it may be treated by conventional means
to reduce mercaptans. The runs were compared with runs using a
standard chlorided platinum on alumina reforming catalyst.
3816 - 14 - ~295275
The results oF processing the heart cut (cut 2) are
illustrated in Table 4 below.
TABLE 4
Upgrading of FCC Gasoline 180-300F Fraction
HDTl/REF û.5% Pt-USDY
Catalyst/Process Feed Pt-Al ZEOLITE~
Net ~ Consumption, SCF/B -- 108} -146
la (Nm3/ 3)(19.2) (-26)
Yiel~s and Properties, Wt ~
--+0.6 +0.3
~ S ~ NH3 __ 0.2 0.2
Cl __ 2.1 0.1
13 2 __ 3.2 1.0
C3 __ 8.1 6.3
IC44, Vol ~ -- 3-3 7.0
NC45, Vol % -- 6.4 7.2
a cS~ Gasoline, Vol %100.0 77.5 80.1
RûN ~ 0 88 98.2 98.5
~ON ~ O -- 90.0 90.4
RVP ~~ (3.6) 3.6
Sul~ur, ppmw 2100 0.5 1.2
Nitrogen, ppmw 37 0.2 0.6
Aromatics, Wt % 37.3 47-5 50-3
al~ins 16.3 Q.o o.o
~ensity ~t 60F (16C)0.7770 0.795 n. 794
3~ I Hydrotreating
Process Conditions: sOOF (482C), 250 pslg (1825 kPa),
4.0 LHSV, 4000 SCF/B (712Nm3/m3)H~
3 Includes HDT Consumption 400 SCF/B(71.2Nm3/m3)H2
4 Iso-butane
Normal Butane
3816 - 15 - ~z9~z~5
Yields comparable to those achieved by conventional
hydrotreating and reforming were obtained when processing the
intermediate boiling range fraction, as illustrated in Table 4. It
is worthy to note that the yield of iso-butane was considerably
greater over the zeolite catalyst, mainly due to a reduction in
light gas make, and was a potential source of additional alkylate.
This reduction in light gas make could result in increased hydrogen
purity in the recycle gas.
As illustrated in Table 5 below, processing the heavy FCC
~soline fraction appears particularly attractive.
ld TABLE 5
Upgrading of FCC Gasoline 300F (149C) Fraction
0.5% Pt-USDY
Catalyst~Process Feed Zeolite
Yields and Properties, Wt. %
2 __ - 0.8
H~S ~ NH3 -- 0.89
1 -- 0.2
2 -- 1.8
3 -- 4.4
IC4, Vol ~ -- 3.1
~C4, Vol ~ -- 5.4
~+ Gssoline, Vol % 100.0 88.4
RON ~ O 90.0 103.3
M~ ~ O -- 93.7
RVP -- ~ 2.6
5~1Pur, ppmw 8400 3.5
Nitro9en~ ppmw 160 1.3
3~ Promatics, Wt ~ 61.4 72.6
Ole~ins 8.4 0 0
Density at 60F (16C) 0.8706 n. 858
1 Process Conditions: 900F (482C), 250 psig (l825kpa),
2.0 LHSV, 4000 SCF/B (712Nm3/m3H2
: ,
:
.
i~295Z7~;
3816 - 16 -
The heavy FCC gasoline fraction is presently hydrotreatedin a number of refineries to remove sulfur. Both the high sulfur
level of about 8ûOO ppm and high end point of about 450F (232C)
preclude conventional hydrotreating/reforming. The results here
indicate that net gasoline yields on this fraction, approaching 97
vol ~, could be achieved with an octane gain of about 13 RON and a
reduction of sulfur in the product to less than 10 ppm.
Combining the processed fractions with the untreated
~lefinic light gasoline results in a significant gain in overall FCC
gasoline octane, with minimal loss of yield. As disclosed in Table
1~ ~ below, it is estimated that about 90 vol % yield of C5+ gasoline
could be obtained with an octane gain of 7 RON and a reduction of
sulfur from 0.30 wt % to less than 0.02 wt ~. The olefin content of
the gasoline is substantially reduced, with an increase in aromatics.
TA8LE 6
ûverall Estimated Yields and Gasoline Properties
Joliet FCC
Gasoline Net Productl A
~, Wt ~
, Wt ~ -- 0.305
NH3, Wt ~ -- -0.007
~1' Wt ~ -- 0.05
~, Wt ~ -- 0.84
, Wt % -- 3.65
IC~, Vol ~ -- 3.48 +3.5
NC4, Vol ~ -- 4.02 +4.0
C5+ Gasoline, Vol ~. 100 89.9 -9.1
C5+ Properties
RON+O 89.9 97.0 +7.1
~ûN+O 79.7 86.6 +9.9
RVP+O 5.15 6.70
~95275
3816 - 17 -
Sulfur, ~t % 0.300 0.0162
Nitrogen, ppmw 60 6
Aromatics 30.5 49-4
Olefins 22.8 11.3
Linear blendin of untreated liaht FCC gasoline and
processed interme3iate and heavy fractions
Lcwer if olefinic light gasoline Merox treated
a
Thus, the present process offers the potential for both
increasing the overall FCC gasoline pool octane and reducing the
level of sulfur. Direct processing of the intermediate and heavy
FCC gasoline fractions using a process of this type could be an
attractive alternative to conventional hydrotreating/reforming or
hydrodesulfurization of FCC feeds.
Further, by the process of the present invention, the
catalyst can operate in the presence of a higher level of sulfur
without any significant aging of the catalyst. The conventional
2a reforming processes can tolerate olefins in the feed which generally
tend to coke very rapidly over conventional catalysts at reforming
oonditions. The net result of this process is a high octane
gasoline that is low in sulfur with a minimal loss of yield.
