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Патент USA US3092576

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United States Patent O??cc
Patented June 4, 1963
On the other hand, part of the product can be diverted to
gasoline usage, with the higher boiling product fractions
either being used for non-gasoline purposes or recycled
Robert H. Kozlowski and Harold F. Mason, Berkeley, 01
and John W. Scott, Jr., Ross, Calif., assignors to Cali
fornia Research Corporation, San Francisco, Cali, a
corporation of Delaware
No Drawing. Filed Jan. 14, 1960, Ser. No. 2,363
4 Claims. (Cl. 208-57)
to the hydrocracking zone for further conversion to
gasoline products. Still another method for working up
the e?luent from the hydrocracking step is to recover
said lower boiling fractions for gasoline, with the next
higher boiling fraction such, for example, as one boiling
from about 350 to 575° F., being utilized for jet, diesel
10 or stove fuels and with the still higher boiling bottoms
fractions then being recycled to the hydrocracking zone
This invention relates to a method for the catalytic
for further conversion to lower boiling products. It is
conversion of hydrocarbon distillate fractions to lower
boiling products. In essence, it is directed to a unitary
contemplated that those fractions of the recovered gaso
line stream which contain cyclic components preferably
process involving a sequence of steps wherein a hydro
carbon feed stream incorporating aromatic compounds 15 be passed through a catalytic reformer under reforming
conditions so as to convert naphthene compounds pres
having at least 9 carbon atoms in the molecule and which
ent to the corresponding aromatics inasmuch as the latter
is extremely low in nitrogen-containing compounds, is
compounds constitute preferred gasoline blending stocks.
hydrogenated under conditions favoring saturation of
The feeds which are usefully employed in the practice
the aromatic compounds and is then hydrocracked at
of this invention are hydrocarbon distillates which con
relatively low temperatures to produce a synthetic prod
tain aromatic compounds having at least 9 carbon atoms
uct stream ‘having an extremely high ratio of iso to non
in the molecule, and which boil above about 300° F.
mal paraf?ns in the C4-C5 range. Moreover, in the case
Representative feeds are those generally de?ned as heavy
of many feed stocks, the product so formed tends to
naphthas boiling ‘in a range from about 300 to 475° F.,
be unusually rich in those cyclic hydrocarbons contain
ing from six to eight carbon atoms in the molecule which
kerosenes, light and heavy gas oils, light and heavy coker
distillates, and light and heavy catalytic cycle oils and
are of particular utility for gasoline blending purposes.
the like. Various of these 'feeds are of straight run
In line with known methods for the hydrocracking
origin, while others are recovered as distillate product
of petroleum fractions wherein the feed is ?rst hydro
fractions from various processing units such as cokers or
?ned to clfect removal of nitrogen- and sulfur-contain—
other cracking units of the thermal or catalytic variety.
ing impurities and is then passed, along with hydrogen,
Other appropriate feed stocks comprise the e?luent por
over a catalyst incorporating hydrogenating and active
cracking components, it is found that the aromatic com
pounds present in the feed tend to be converted to pri
mary products having but one, two, and in some cases
three fewer carbon atoms than the corresponding pre
cursor compounds. Thus, to take a typical example
wherein a heavy naphtha boiling over a range of from
about 360 to 450° F. and containing approximately 40%
aromatics is subjected to a sequence of hydro?ning and
tions boiling above about 300—325° F. as obtained from
a catalytic reforming unit, such stocks being convention
ally produced by passing straight run, thermally cracked
and/or catalytically cracked naphthas, along with added
hydrogen, over a platinum-o-n-alumina or a molybdenu
alumina catalyst under reforming conditions. Still other
suitable feed stocks include concentrates rich in aromatic
hydrocarbons, as obtained by the extraction of various
hydrocracking steps, it is found that the synthetic prod 40 hydrocarbon fnactions with sulfur dioxide, furfural, mix
tures of various polyethylene and polypropylene glycols
uct fractions boiling below about 360° F. are rich in C9
aromatic components and contain relatively smaller
amounts of compounds such as benzene, toluene, and
or the like.
preferred gasoline blending stocks from both the octane
While the invention ?nds particular utility in connec
tion with the treatment of distillate fractions derived
either directly from crude petroleum or from process
and volatility standpoints.
The present invention is supported by the ?nding that
within the scope of the present invention to employ dis
xylene (or their naphthenic equivalents) which constitute
units working with petroleum hydrocarbons, it is also
tillate feed stocks derived from other sources such as
when an aromatics saturation step is interposed between
shale, gilsonite, coal, or the like. In general, it is pre
the hydro?ning step and one of hydrocracking conducted
at low temperatures of from about 300 to 700° F., cyclic 50 ferred to employ feed stocks wherein at least the
ASTM D—86, D-l58, or D-l160 10% and 90% dis
compounds present in the feed which contain 9 or more
tillation points fall within a range of from about 350 to
carbon atoms in the molecule are converted in large
950° F.
part to cyclic product compounds, principally naphthenes,
Reference has been made above to the fact that the
which contain four less carbon atoms than the corre
present invention is practiced with feeds which contain
sponding precursor compounds. Thus, in the case dis
aromatic components. The content of the latter com
cussed above wherein a naphtha is employed as feed, the
pounds is not critical, and the invention ?nds utility with
use of a sequence of hydro?ning, aromatics saturation
stocks, as exempli?ed by those set forth above, wherein
and low temperature 'hydrocracking steps can be expected
the content of aromatics ranges all the way from about
to give a synthetic product which is relatively rich in C7
and Ca naphthenes. It was also found that a practice of 60 1 to 100 volume percent.
Feeds of the type described above normally contain
the present method not only affords a substantial in
a substantial proportion of nitrogen-containing impurities,
crease in the amounts of C4-C5 para?ins produced during
along with those of sulfurous character. Accordingly,
the hydrocracking step and a reduction in C1-C3 paraf
as the ?rst step in the process when dealing with feeds of
?ns, but also effects a qualitative change in that the
ratio of iso to normal compounds in said para?ins is 65 this character, the feed is subjected to a hydro?ning treat
many times greater than that which is observed in proc
ment to reduce the nitrogen content thereof, preferably
esses omitting the aromatics saturation step.
to a level of from 0 to 10 p.p.m. expressed as total nitro
It is also a feature of the present invention that the
gen. This can be effected by contacting the feed, along
product obtained following hydrocracking is very low
with at least 500 s.c.f. of hydrogen per barrel thereof,
in aromatic content. Accordingly, all portions of this
with a sulfur-resistant hydrogenation catalyst at tempera
product which boil in the proper range are well adapted
tures of from about 450° to 800° F., pressures of at least
to be used for jet and other non-gasoline fuel purposes.
300 p.s.i.g., and liquid hourly space velocities (LHSV) of
catalyst used in this second stage may be a sulfuractive
catalyst of the type used in the ?rst, or hydro?ning stage,
or it may consist of supported metals and/or metal oxides
of groups VI, VII and VIII elements of the periodic sys
tem. Thus, Raney nickel can be employed, while other
from about 0.3 to 5. As is conventional in hydro?ning
operations having as their objective the removal of nitro
gen-containing and sulfur-containing ingredients, the con
ditions of the hydro?ning step are so chosen that satura
tion of aromatic components is generally limited, and so
that little cracking of the feed takes place other than that
suitable catalysts comprise molybdenum oxide, platinum,
of the nitrogen-and sulfur-containing compounds present.
Any of the known sulfur-resistant hydrogenation catalysts
palladium, rhodium, rhenium, nickel or cobalt and the
like supported on alumina, silica gel, kieselguhr or other
one or more oxides or sul?des of the transition metals
saturation comprises one containing about 0.1 to 20% or
more of metallic platinum supported on an alumina base.
similar carriers of low cracking activity and high surface
may be used in the present process. The preferred cata
lysts of this category have as their main active ingredient 10 area. A preferred catalyst for use in effecting aromatics
such as cobalt, molybdenum, nickel, and tungsten, or of
their reduced counterparts. These materials may be used
in a variety of combinations with or without the use of
various known stabilizers and promoters. Morever, these
catalysts may be employed either alone or in combina
tion with various conventional supporting materials such
These catalysts may also contain from 0.1 to 2%, by
Weight, of halogen components such as ?uorine or chlo
r rine, thus including those platinum reforming and other
catalysts of the type presently employed in catalytic re
forming operations.
as charcoal, fullers earth, kieselguhr, silica gel, alumina,
bauxite, or magnesia. A representative effective hydro
The effluent from the aromatics saturation (i.e., hydro
genation) step can be handled in a variety of ways. Thus,
?ning catalyst for use in the present invention is one em
it can be passed to a gas liquid separator to recover a
hydrogen-rich gaseous stream which can be recycled back
over the hydrogenation catalyst along with fresh makeup
and/ or tungsten in the sul?de or oxide form, in the amount
hydrogen. The remainder of the effluent can then be
of about 5 to 25% expressed as Mo or W, together with
sent to storage for later processing over the hydrocrack
oxides or sul?des of cobalt and/or nickel, the latter ma
terials being present in the amounts of from about 1 to 25 ing catalyst. Alternatively, said remainder can be frac
tionated to recover particular product cuts, with the bal
20%, expressed as Ni or Co.
bodying an alumina support and containing molybdenum
ance of the material then being passed along with added
hydrogen, to the hydrocracking unit. In thus carrying
out the process, the hydrogenation catalyst will normally
The ef?uent obtained from the hydro?ning step is
treated, in accordance with methods presently known in
the art, so to remove ammonia and some hydrogen sulfide
which may be present. A preferred removal method in 30 be supported in its own reactor vessel. However, in the
preferred practice of the invention, the entire effluent
volves injecting water into the total e?luent from the
hydro?ning unit and then passing the resulting mixture
from the hydrogenation catalyst is passed directly, along
into a high pressure separator‘ operating under such con
with added amounts of hydrogen, where required, over
ditions of temperature and pressure (for example, 100°
the hydrocracking catalyst. This permits the hydrogena
F. and 950 p.s.i.g.) that a gaseous overhead is removed 35 tion catalyst to be supported in the same reactor shell
as the hydrocracking catalyst but in a position such that
that is predominantly hydrogen but which normally con
tains some hydrogen sul?de and light hydrocarbons. This
necessary aromatics saturation is accomplished within said
shell prior to passing the stream over the hydrocracking
catalyst. On the other hand, it will be obvious to those
overhead (following a clean-up treatment to remove any
nitrogen and sulfur-containing compounds, if desired),
can ‘be recycled to the hydro?ning unit along with make 40 skilled in the art that in this method of operation, as in
up hydrogen. Two liquid phases are formed in the sepa
that referred to above, the hydrogenation catalyst may be
rator, an upper hydrocarbon phase and a lower aqueous
supported in a reactor unit which is separate from that
phase which contains essentially all of the ammonia pres
used to contain the hydrocracking catalyst.
ent and some hydrogen sul?de in the form of ammonium
The catalyst employed in the hydrocracking unit is an
sul?de. The aqueous phase is removed from the system 45 acidic material having hydrogenating characteristics and
high cracking activity. It is made up of a hydrogenating
and discarded.
The hydrocarbon layer is then preferably passed into
component together with a material having a high degree
a stripper or distillation column from which any remain
of cracking activity either per se or when combined with
ing hydrogen sul?de, ammonia and water are removed
the material employed to provide a hydrogenating com
50 ponent of the catalyst. In this connection, the term
As the next step in the process, the portion of the hy
“high cracking activity” is employed herein to designate
dro?ned e?luent to be hydrocracked is passed, along with
those catalysts having activity equivalent to a cat. A
added hydrogen, over a hydrogenation catalyst under
value of at least 25 or a quinoline number of at least 20
elevated conditions of temperature and pressure effective
(Journal Am. Chem. Society, 72, 1554, (1950)). In the
to saturate a substantial portion of the aromatics present 55 case of catalysts not adapted to withstand the conditions
in the feed, the process in most operations effecting sat
employed in such tests, generally comparable, minimal
uration of at least 50% of the aromatic compounds pres
cracking activity values can be determined by other
ent. Hydrogen is supplied along with the feed in an
methods known in the art.
amount at least sufficient to effect said saturation, and
Broadly speaking, the hydrogenating component of the
preferably an excess of hydrogen is used so as to supply 60 catalyst may comprise one or more of the metals, and
at least a portion of that required during the ensuing
hydrocracking step, which is also consumptive of hydro
compounds of said metals, in groups I(B), II(B), V, VI,
VII, and VIII of the periodic table. However, when, as
in the preferred embodiment of the present invention, it
is desired to provide a synthetic product fraction from
gen. This permits the entire e?luent from the satura
tion zone to be passed directly to the hydrocracking zone,
if this method of processing is adopted. For most feed
stocks, the dual requirements of aromatics saturation and
of saturation of cracked products can be met by adding
to the feed passed to the aromatics saturation zone at
least 2000 s.c.f./H2 per barrel of said feed, and preferably
at least 3000 s.c.f./H2 per barrel are so used.
The conditions employed in the aromatics saturation
zone are generally similar to those employed in the hydro
?ning step except that here the temperatures employed
the hydrocracking zone having a ratio of iso to normal
paraffinic components which is far above the theoretical
thermodynamic equilibrium values at the temperatures
employed, the hydrogenating component of the catalyst
is selected from one or more of the various compounds of
metals falling within the aforesaid groups which are not
readily reduced to the corresponding metal form under
the reducing conditions prevailing in the hydrocracking
zone. Thus, while the invention is operable with catalysts
are somewhat lower, being of the order of 300 to 700° F.,
with a preferred range being from 400 to 650° F. The 75 such as those having platinum or a compound such as
nickel oxide or cobalt oxide which is readily reduced to
the corresponding metal form in the hydrocracking zone,
it is preferred to use compounds not readily reduced such
as an oxide or sul?de of molybdenum, tungsten, chro~
of a crushed silica-alumina aggregate with a solution pre
pared by mixing 1500 milliliters Water and 500 milliliters
of ammonium hydroxide solution with 1082 grams of
ethylenediamine tetraacetic acid (EDTA) and 469 grams
of nickel carbonate, the solution being made up to a
total of 4000 milliliters with water. The impregnated
miurrr, rhenuim, or zinc, or a sul?de of cobalt, nickel,
copper, or cadmium; other hydrogenating materials fall
ing within this preferred category are complexes of the
material was held for a period of 24 hours at 70° F., ‘fol
various metals of the de?ned groups such, for example,
lowing which it was centrifuged and calcined for 10 hours
as cobalt-chromium and nickel chromium‘. Representative
at 1000° F. in air to convert the nickel chelate to nickel
preparations of this character are described in US. Patent 10 oxide. The catalyst was then reduced in an atmosphere
No. 2,899,287. If desired, more than one hydrogenating
of hydrogen at 650° F. and 1200 p.s.i.g. and sul?ded in
component may be present. The amount of the hydro
situ in the reactor by the use of a feed- stream made up
genating component may be varied within relatively Wide
of a catalytic cycle oil (49 volume percent aromatics) to
limits of from about 0.1 to 35% or more, based on the
which 0.1% by volume of dimethyl disul?de had been
weight of the entire catalyst composition.
15 added, at a pressure of 1200 p.s.i.g., ‘and in the presence
The remaining, or cracking component of the hydro
of approximately 6500 s.c.f. H2 per barrel of feed.
cracking catalyst may be selected from a variety of solid
or liquid materials of the type having good cracking activ
ity. Among solid compositions which can be used are
Nickel sul?de (2.5 % Ni) on silica-alumina: This
catalyst (No. 353) was prepared by impregnating ap
proximately 7.5 liters of a crushed SiO2~A12O3 aggre
the various siliceous cracking catalysts, those wherein 20 gate which had been dried in air for 24 hours at 400° F.,
alumina is chemically bonded to aluminum chloride, ?uo
with 2183.7 grams of Ni(NO3)2-6H2O dissolved in water
and made up to a total of 7760 milliliters The impreg
rided magnesium oxide, and aluminum chloride, partic
ularly when contained within the pores of a support such
as charcoal so as to reduce vaporization of the AlCl3.
nated base material was then held for 24 hours at 70° F.
and calcined for 10 hours at 1000° F. The catalyst was
Representative liquid catalysts having a high degree of 25 then sul?ded by treatment in an atmosphere of hydrogen
cracking activity are hydrogen ?uoride-boron tri?uoride
compositions, titanium trichloride, and aluminum chloride
containing 8% hydrogen sul?de at 1200 p.s.i.g. and
580° F.
as contained in a suitable hydrocarbon vehicle along
Cobalt sul?de (4% Co) on silica-alumina: This catalyst
with HCl.
(No. 248-2) was prepared by impregnating 2000 milli
In general it is preferred to employ a solid siliceous 30 liters of a crushed SiOz—Al2O3 aggregate with 1500
milliliters of an aqueous solution containing 172.5 milli
material as the cracking component of the catalyst. For
liters ammonium hydroxide solution and 373 grams
example, there may be used composites of silica-alumina,
EDTA along with 168 grams cobalt carbonate, the solu
silica-magnesium, silica-alumina-zirconia, acid treated
tion being heated until bubbling ceased before being added
clays and the like, as well as synthetic metal aluminum
silicates (including synthetic chabazites normally referred 35 to the silica-alumina material which, in turn, had pre
viously been dried for 24 hours at 400° F. Following
to as “molecular sieves”) which have *been found to im
impregnation, the catalyst was centrifuged and calcined
part the necessary degree of cracking activity to the cata
for four hours at 1000° F., thus yielding a material having
lyst. Particularly preferred siliceous catalyst components
an amount of cobalt oxide equivalent to 2.2% weight
are synthetically prepared silica-alumina compositions
having a silica content in the range of from about 40 to 40 percent Co. A second impregnating solution was then
99% by weight.
made up as above, using 150.2 grams cobalt carbonate,
334 grams EDTA and 154 milliliters of ammonium hy
Particularly good results from the standpoint of high
droxide and added to the catalyst. Following a holding
per-pass conversion, even at relatively low operating tem
period of 24 hours at 70° F., the catalyst was centrifuged
peratures, coupled with high iso/normal ratios and the
ability to withstand repeated regeneration with but rela 45 ‘and calcined for 10 hours at 1000“ F. The calcined
product so obtained was then alternately reduced in hy
tively minor decreases in activity, are obtained with cata
drogen and oxide in air (repeating the cycle 5 times) at
lysts comprising a total of from about 0.1 to 35 wt. per
1000° F. and 1200 p.s.i.g. The catalyst was then sul
cent of at least one compound selected from the group
?ded by treatment with an excess of a mixture compris
consisting of cobalt sul?de and nickel sul?de, said com
pounds being deposited on the aforementioned syntheti 50 ing 10% ‘by volume of dimethyl disul?de in mixed hex
anes at 1200 p.s.i.g. and 675° F., hydrogen also being
cally prepared silica-alumina composites. Of these cata
present in the amount of about 6500 s.c.f. per barrel of
lysts, those containing nickel sul?de are found to have
the highest activity.
Cobalt sul?de (2% Co) and chromium sul?de (3.53%
The following hydrocracking catalysts are representa
tive of those which are adapted to be used in a practice 55 Cr) on silica-alumina: This catalyst (No. 174—5) was
prepared by forming an aqueous slurry with 1130 grams
of the present invention, the support in each case being
of the chelate of chromium and EDTA, to which slurry
a synthetically prepared silica-alumina composite con
was ‘added 196 grams of cobalt carbonate, the solution
taining about 87-90% silica and having a cat. A value
being then stirred until bubbling action ceased and made
of 46.
Nickel sul?de (3.6% Ni) on silica-alumina: This 60 up to 1779 milliliters. This solution was warmed to 140°
F. vand added to 2280 milliliters of the crushed
catalyst (No. 425-2) was prepared by impregnating 11
SiO2—Al2O3 aggregate. The resulting material was then
liters of a crushed silica-alumina aggregate with 2896.9
held for 24 hours at 140° F., following which it was cen
grams of Ni(NO3)2'6H2O, dissolved in enough water to
triguged and calcined 10 hours at 1000° F. The calcined
make 8800 milliliters total solution, ‘following which the
beads were held for 24 hours at 70° F. The catalyst was 66 product was reduced in an atmosphere of hydrogen at
1200 p.s.i.g. and 675° F., following which the cobalt and
then dried for 10 hours at 250° F. and thereafter calcined
metals present were converted to sul?des by
at 1000° F. for 10 hours. The calcined material was re
treatment with an excess of a solution comprising 10%
duced in an atmosphere of hydrogen at 580° F. and 1200
by volume of dimethyl disul?de in mixed hexanes at 1200
p.s.i.g., following which the resulting nickel-bearing 70 p.s.i.g. and 675° F., hydrogen also being present in the
catalyst was sul?ded in an atmosphere containing 8%
H28 in hydrogen at 1200 p.s.i.g. and 580° F., thereby
converting essentially all the nickel to nickel sul?de.
Nickel sul?de (2.5% Ni) on silica-alumina: This
amount of 6500 s.c.f. per barrel of feed.
Molybdenum sul?de (2% Mo) on silica-alumina:
This catalyst (No. 226) was prepared by forming 530
milliliters of an ammoniacal solution containing 41.4
catalyst (No. 316) was prepared ‘by impregnating 11 liters 75 grams of ammonium molybdate. This solution was then
than would otherwise be the case.
added to the crushed SiO2-—Al2O3 aggregate, previously
Preferred initiating
dried for 24 hours at 400° F., in an amount su?icient to
temperatures are in the range of from about 350 to 650°
yield a dried product containing the equivalent of 2
weight percent Mo. After being held for 24 hours at
70° F., the impregnated material ‘was centrifuged and
herein are less refractory than those which have not been
F., it being noted that the saturated feed stocks produced
It was then reduced
previously saturated, and thus can be hydrocracked at
signi?cantly lower temperatures than would otherwise be
monia were mixed with 80 milliliters water and added to
49.3 grams EDTA, and to this solution was added 22.3
at one or more points in the reactor shells employed to
contain any one or more of said catalysts for quench,
calcined for 5 hours at 1000° F.
in an atmosphere of hydrogen at 1200 p.s.i.g. and 650°
The ef?uent from the ‘hydrocracking reactor may be
F., following which it was sul?ded in situ by treatment
worked up in any convenient fashion. Thus, a gas recycle
under these same conditions of temperature and hydro
gen pressure with a hydro?ned cycle oil (49% aromatics) 10 stream rich in hydrogen is customarily separated in a
high pressure gas-liquid separation zone, which stream
containing 1% by volume .dimethyl disul?de.
can be recycled for admixture with the feed passing over
Nickel sul?de (1% Ni) and molybdenum sul?de (1%
the hydro?ning, hydrogenation or hydrocracking catalysts.
Mo) on silica-alumina: This catalyst (No. 296) was pre
Alternatively, part or all of said hydrogen can be injected
pared in the following manner. 28.6 milliliters of am
or temperature control purposes.
grams of nickel carbonate. After being heated to evolve
Thereafter, C1—C3 or
C1-C4 products are separated in a gas-liquid separation
carbon dioxide, this solution was mixed with another
zone operated at lower pressures, thus leaving a normal
solution prepared by dissolving 78.7 grams. of ammonium
ly liquid effluent portion from which fractions boiling in
molybdate in a mixture of 80 milliliters of ammonia hy
droxide and 80 milliliters of water. The resulting solu
tion, on being made up to 480 milliliters by the addition
of Water, was then used to impregnate 600 milliliters of
the gasoline range can be recovered. Said fractions may
be used as gasoline components, or more preferably, their
The impregnated
octane ratings can be greatly improved by passing ap
propriate portions thereof (e.g., one boiling from about
material, after ‘being held for 24 hours at 70° F., was
centrifuged and calcined for a period of 10 hours at
1000° F. It was then reduced in an atmosphere of hy
forming conditions. Products in the hydrocracking efflu
ent boiling above the desired end point of the gasoline
the crushed SiO2-——Al3O3 aggregate.
180 to 400° F.) through a catalytic reformer under re
fractions can be employed in whole or in part for jet or
other fuel purposes, or they may be recycled back over
the hydrocracking catalyst or over both the hydrogena
tion and the hydrocracking catalysts. Thus, in one em
drogen at 1200 p.s.i.g. and 650° F., following which it
was sul?ded under these same conditions of temperature
and hyddrogen pressure with a solution containing 10
volume percent dimethyl disul?de in mixed hexanes.
Returning now to a general teaching of the present in
vention, it is to be noted that whatever the nature of the
bodiment of the invention, fractions boiling below about
300-375° F. are recovered as gasoline blending stocks,
a next higher boiling fraction having an end point of
previous hydro?ning and saturation steps, the resulting
saturated, low nitrogen feed stock is passed, in admixture
with at least 500 s.c.f. of hydrogen per barrel of total
feed (including both fresh as well as recycle feed) over
the hydrocracking catalyst at temperatures of from about
350 to 700° F. and at pressures of at least 400 p.s.i.g.
At least 250 s.c.f. and normally from about 500 to 1500 40
s.c.f. of hydrogen are consumed in the hydrocracking re—
action zone per barrel of total feed converted to syn
about 550 to 600° F. is diverted for jet fuel purposes, and
any remaining bottoms are recycled through the aromatics
saturation and hydrocracking zones.
The advantages to be obtained by a practice of the
present invention are illustrated by the data of the fol
lowing examples:
In order to show the difference between the nature of
thetic products, i.e., those boiling below the initial boiling
the products obtained when hydrocracking an aromatic
point of the feed to this zone.
compound of representative molecular weight as com
As indicated above, the pressures employed in the hy
pared with those obtained in a similar operation wherein
drocracking zone are in excess of 400 p.s.i.g., and they
the same compound is ?rst saturated and then hydro
may range upwardly to as high as 3000 p.s.i.g. or more,
with a preferred range being from about 500 to 2000
cracked, hexamethylbenzene (nitrogen-free) was passed
over a hydrocracking catalyst comprising nickel sul?de
50 (3.6 wt. percent Ni) on a synthetically prepared silica
Generally, the feed may be introduced into the hydro
cracking zone at a liquid ‘hourly space velocity (LHSV)
of from about 0.2 to 5 volumes of hydrocarbon (cal
culated as liquid) per super?cial volume of catalyst, with
a preferred rate being from about 0.5 to 3 LHSV.
One of the most advantageous aspects of the subject 55
process is that the average reaction temperature over the
hydrocracking catalyst is maintained below about 700° F.
The importance of such low temperature operations is
alumina support at an average temperature of 650° F"
pressure of 1200 p.s.i.g., and a LHSV of 8.0, along with
6700 s.c.f. H2 per barrel of feed. The per-pass conver
SlOl'l in this operation was 97.8% to products boiling
below the initial boiling point of the feed compound.
As shown by the data presented in Table I below, a large
proportion of the feed was converted to Cm and C11
aromatic compounds.
A similar operation was then conducted using the cor
reflected in long on-stream periods extending over many
hundreds of hours in the production of extremely low 60 responding saturated compound (hexamethylcyclohexane)
yields of C1—C3 light gases, and in the formation of a
as the starting compound. Here the nitrogen-free feed
synthetic product having iso to normal para?in ratios
far in excess of thermodynamic equilibrium values.
the preferred practice of this invention, the temperature
at which the hydrocracking reaction is initiated when plac
ing a fresh charge of catalyst on-stream should be as
low as possible (commensurate with the maintenance of
was passed at a pressure of 1185 p.s.i.g., a temperature
of 550° F., and an LHSV of 8, along with 6533 s.c.f./Hz
per barrel of feed, over a hydrocracking catalyst contain
ing nickel sul?de (6 wt. percent Ni) on the synthetic
silica-alumina cracking support. This catalyst was some
what more active than that employed in the conversion
adequate per~pass conversion levels) since the lower the
of hexamethylbenzene, such activity being signi?cant, as
starting temperature the longer will be the duration of
the said on-stream period. For any given conversion, 70 regards the data of comparative runs here being described,
only in that it permitted temperatures to be reduced from
650 to 550° F. while maintaining other conditions, in
cluding per-pass conversion, substantially the same. The
conversion in this operation was 99.8% per pass, and
version under given operating conditions) permit the unit
to be placed on-stream at lower starting temperatures 75 Table I below shows the product distribution obtained.
the permissible starting temperature is a function of cat
alyst activity inasmuch as the more active catalysts (i.e.,
those capable of effecting a relatively high per-pass con
The foregoing feed was hydro?ned by passing the same,
along with 3000 set". Hg/bbi. feed, at 720 p.s.i.g, 730°
F., and 1.0 LHSV over a hydro?ning catalyst comprising
104 wt. percent molybdenum oxide and 3.6 wt. percent
cobalt oxide, the balance being alumina. The resulting
Table I
Moles of Product per 100 Moles of Feed
Hexamethyl- Hexamethyl
Methane ________________________________ __
l0. 3
0. 14
Ethane __________________________________ _ -
4. 0
0t 16
Propane _________________________________ __
Isohexanes_ _
0. 2
0. 9
3. 4
4. 2
15. 7
8. 4
On; Naphthenes. ____
Cu Naphthenes _________________________ __
2. 2
019 Naphthenes._
0. 1
Pseudocu mane .
Hemirnellitene ____ _-
Durene, Isodurene ______________________ __
Prohnitone ________ __
C10 Aromatic ______ __
the following speci?cations.
58. 68
2. 28 10 Gravity, ° API _____________________________ __ 29.5
22. 75
Aniline point, "F __________________________ __
0. 39
Nitrogen content, total ppm ________________ __ 2.1
D. 23
Aromatic content, vol. percent ________________ __
3. 62
17. 86
Para?ins, vol. percent _______________________ __
62. 26 15
Naphthcnes, vol. percent ____________________ __
3. 71
Freezing point, ‘‘ F _________________________ __ ~29
Pour point, ° F ____________________________ __. ~41
ASTM distillation D158, ° F .:
0. 5
C4 NaphthencsC1 Naphthenes.
C5 Naphthenes.
Cr Naphthenes___
gen, hydrogen sul?de, ‘ammonia, other gases and water
soluble compounds, leaving a hydro?nd stock having
7. 80
37. 3
5. 9
11. 8
1. 4
n-Kexane ______________ _ _
material was thereafter treated so as to remove hydro
0. 7
21. 2
2. 7
0. 5
19. 3
2. 2
_________________________________ _..
_________________________________ __ 436
_________________________________ __ 470
_________________________________ __ 506
End point ______________________________ __ 522
The above hydro?ncd stock. was then split into two
portions, with one portion being saturated and then
From the data of the above table, it is evident that
saturation of an aromatic compound prior to hydro
cracking the same enables the resulting naphthene to be
hydrocracked, and the other portion being only hydro
crackcd. The ?rst of these samples was hydrogenated
4 fewer carbon atoms than the feed compound. It will 30 by passing the same, along with 6500 s.c.f. Hg/bbl. feed,
over an alumina-supported platinum catalyst (0.75 Wt.
also be observed from said data that the saturated feed
Pt, 0.8 wt. percent halogen) at 650° F., 1200
stock provides a much higher yield of the desired light
p.s.i.~g. and 20 LHSV. This ‘saturation operation, which
isopara?in compounds containing from 4 to 6 carbon
entailed a hydrogen consumption of about 1 100 s.c.f./bibl.
atoms in the molecule, while at the same time effect
ing a corresponding reduction in the amounts of undesired 35 feed, yielded a product having the following inspections:
hydrocraoked in major portion to a naphthene containing
lighter gases and normal CQ-CB para?ins formed. In this
latter connection, it is to be observed from the date of
Table II given below, which derives from that shown
in Table I, shows that the ratio of iso to normal com
ponents in the case of the saturated feed stock is many 40
Gravity, ° API ____________________________ __
Aniline point, ° F _________________________ __
Pana?ins+naphthenes, vol. percent __________ __
Aromatics, vol. percent _____________________ __
Freezing point, ° F _________________________ __
times higher than that obtained using hexamethylbenzene
Smoke point, nun _________________________ -..
and is far above the iso/normal ratio as calculated from
The hydrogenated product was then hydrocracked by
passing the same, along with 12,000 s.c.f. H2/bbl. feed,
thermodynamic equilibrium considerations.
Table II
45 over a catalyst comprising nickel sul?de (2.6% Ni) on
a synthetic silica (90%)-alumina cracking support, at
an ‘average temperature of 534° F., a pressure of 1200
Hexamethyl- Hexarnethyh
650° F.
650° F.
p.s.i.g., and a LHSV of 1.1, under which conditions the
conversion to product boiling below 360° F. was ap
50 proximately 59 volume percent pro-pass. In this opera
550° F.
650° F.
iCi/IXCi ____________ -_
0. 96
iC5/nC5 ____________ __
ice/n05 1 ___________ __
2. 7
2. 4
57. 7
C1, wt. percent _____________________________ __
C2, wt. percent ____________________________ __
‘Based on single-branched species, such being the type produced
55 C3, wt. percent _____________________________ __
during the hydroeracking step.
tion, the yields were as follows:
In this operation there was employed as feed a catalytic
cycle oil as obtained from a catalytic cracking unit op
erating with a California crude, said feed having the fol 60
iC4, wt. percent ____________________________ __ 6.3
nC4, wt. percent ____________________________ __ 0.7
C5~l80 ° F. out, wt. percent __________________ __ 9.9
180—360 ° F. cut, wt. percent ________________ __ 42.7
360 ° F.+ _________________________________ __ 40.3
lowing speci?cations.
Hydrogen consumption s.c.f./bbl. feed converted“ 663
Gravity, ” API _____________________________ .._ 25.5
Aniline point ‘’ F ___________________________ __
The 180—360'’ F. cut, which contained 4% aromatics,
77% naphthenes, and 19% paraf?ns represented a gaso
line blending stock which could be upgraded to a leaded
Sulfur, wt. percent __________________________ __ 0.98
Nitrogen, total ppm ________________________ __ 900
Aromatics, vol. percent ______________________ __
Ole?ns, voI. percent ________________________ __
Para?ins+naphthenes, vol. percent ____________ __
ing inspections:
_________________________________ __
End point _____________________________ .._ 549
The 360° F.+ cut represented a
good jet stock blending component and had the follow
_________________________________ __
catalytic reformer.
D158 distillation, ° F.:
Start ...___
65 octane value of from 100 to 103 by passage through a
Gravity, " API ____________________________ __ 41.1
Aniline point, ‘’ F __________________________ __
Freezing point, ° F ________________________ __ ~31
Pour point, “F ___________________________ _- —40
Smoke point, mm __________________________ __
Aromatic content, vol. percent _______________ .._
in this operation being 1000 s.c.f./bbl. of feed. The
When, in a companion operation, the same operation
as described above was repeated, but using the catalyst
of Example I and without the practice of a hydrogena
tion step, it was found that the temperature of the hydro
cracking catalyst, other conditions remaining the same,
hydrogenated product had the following inspections.
Gravity, °API ____________________________ __
Aniline point, ° F _________________________ __ 156.0
Para?ins, vol. percent ______________________ _Naphthenes, vol. percent ___________________ __
Aromatics, vol. percent ____________________ __
had to be raised to approximately 569° F. to get a com
parable per-pass conversion. The product yields in this
operation were as follows:
C1, wt.
ASTM distillation D-15B, ° F.:
Start __________________________________ __
percent ___________________________ __
C2, wt. percent ___________________________ __
C3, wt. percent ___________________________ __
iC4, wt. percent ___________________________ __
nC4, wt. percent __________________________ __
C_.-,—~l80° F. cut, wt. percent _______________ __ 11.2
180—360° F. cut, wt. percent ______________ __ 42.01
360° F.+ fraction, wt. percent ______________ __ 40.1
10% __________________________________ __ 414
30% __________________________________ __ 430
50% __________________________________ __ 445
70% __________________________________ __ 462
90% __________________________________ __ 495
End point _____________________________ __ 539
The foregoing hydrogenated product was then hydro
cracked by passing the same, along with 6500 s.c.f.
Hz/bbl. feed, at 1200 p.s.i.g., 479° F. and 0.8 LHSV,
It will be noted that the ratio of iC4 to nC4 products is 20 over a catalyst comprising nickel sul?de (6 wt. percent
far lower here than the value shown above in connec
Ni) on a synthetic silica-alumina cracking support con
tion with the hyrdrogenated stock.
taining about 90% silica, said support being in the shape
The inspections on the 360° F.+ portion of the prod
of small beads (l/s" diameter) and having a cat. A
uct from the hydrocracking zone were as follows.
value in excess of 40 at the time of being impregnated
25 with the hydrogenating component and before being
Gravity, ‘’ API _____________________________ __ 38.6
thereafter calcined and sul?ded. Under these conditions,
Hydrogen consumption, s.c.f./bbl. feed converted- 1423
Aniline point,
° F __________________________ __
there was obtained a per-pass conversion of 62.3% to
Paraf?ns-t-naphthenes __________________ __ _
synthetic products boiling below 400° F. The wt. per
cent yield of such products, based on the feed converted
Composition, vol. percent:
____________________________ __
30 thereto, was as follows, it being noted that the operation
was consumptive of 1670 s.c.f. H2/bbl. feed converted to
Freezing point, ” F ____________________ __ —27
Smoke point, mm ______________________ __
synthetic product:
Due to its high content of aromatic components, this
C1 ________________________________________ __
stock is not adapted for use as a jet fuel component.
C2 ________________________________________ __ 0.03
C3 ________________________________________ __
i-C4 _______________________________________ .._
‘In this operation, the feed employed was a catalytic
cycle oil having the same speci?cation as that described
180—400° F. cut __________________________ __ 74.9
in Example I]. Here the feed was hydro?ned in two 40
the above data, it will be observed that the ratio
stages; in the ?rst stage the feed was passed, along with
of iso to normal 0., product was extremely high, being
6000 s.c.f. Hz/bbl. feed at 675° F. and 1.0 LHSV, over
13.4. Moreover, losses to C1-C3 gases were insigni?cant.
a catalyst comprising 25.4% molybdenum and 7.5% co
The 180—400° F. cut referred to above had the follow
balt oxide on alumina. In the second stage, the opera
ing inspections.
tion of the ?rst stage was repeated, but at 1.5 LHSV and
a temperature of 685" F. Total hydrogen consumption
Gravity, ° API ____________________________ __ 49,7
was 500 s.c.f./bbl. of feed and the hydro?ned product
Aniline point, ° F __________________________ __ 137
had the following inspections.
Para?‘ins, vol. percent ______________________ __
Naphthenes, vol. percent ____________________ __
Gravity, ‘’ API ____________________________ __ 30.2
Aniline point, ° F __________________________ __ 90.0
50 ASTM distillation D-158, ‘’ F.:
Start ___________________________________ _. 221
Para?ins+naphthenes, vol percent ____________ __
Aromatics, vol. percent _____________________ ..
Total nitrogen, p.p.m _______________________ __ 0.15
ASTM distillation D-158, ° F.:
10% ___________________________________ __ 241
30% ___________________________________ __ 268
50% ___________________________________ __
Start __________________________________ __
10% __________________________________ __ 435
70% ___________________________________ __
90% ___________________________________ __
End point ______________________________ __ 400
30% __________________________________ __ 455
50% __________________________________ __ 467
70% __________________________________ __ 482
90% __________________________________ __
point _____________________________ -_ 557
The hydro?ned feed was then processed by alterna
tive methods.
In the ?rst method the feed was hydro
genated and then hydrocraeked.
In the second, the feed
In the comparison run, made without the practice of the
60 hydrogenation step, the hydro?ned feed was hydro
cracked at the same conditions as described above, ex
cept that, in order to obtain a 60% per-pass conversion
to product boiling below 400° F., it was found to be nec
essary to raise the catalyst temperature from the value
65 of 479° F. noted above, to one of 555° F. Hydrogen
was only hydrocracked. In both cases, the operation
was one of extinction recycle, with all portions of the
product from the hydrocracking unit boiling above 400°
F. being recycled to said unit.
In the ?rst method, the hydro?ned feed was hydro
genated by passing the same, along with 6500 s.c.f.
Hz/bbl. feed, at 1200 p.s.i.g., 500° F. and 3.0 LHSV
over a catalyst comprising 2.0 wt. percent platinum on
an activated alumina support, the hydrogen consumption 75
consumption in this run was 1720 s.c.f. per barrel of con
verted feed, while the wt. percent yield of synthetic prod~
uct, based on converted feed, was as follows:
C1 ________________________________________ __
C2 ________________________________________ __
c, ________________________________________ __
i-C4 ______________________________________ __
II'C4 ______________________________________ .._
c,_1s0° F. cut ___________________________ __ 19.0
l80—400° F. cut ___________________________ __ 70.0
From the foregoing data, it will be noted that the hydro
and 1.3 LHSV, along with 5700 s.c.f. H2/bbl., over a
cracking operation conducted without preliminary hydro
catalyst comprising molybdena (19.1% Mo) and cobalt
genation resulted in considerably more light gas make.
Moreover, the iso to normal C4 ratio was but 2.6 instead
oxide (5.9% Co) on an alumina support. The hydro
?ned product had an aromatic content of 14 vol. percent.
of 13.4.
The 180-400“ F. cut had the following inspections, it
being noted that due to relatively high aromatic content
shown, this product would not be suitable for jet fuel
the same at 1200 p.s.ig., 500° F. and 3.0 LHSV, along
with 6500 set. Hz/bbL, over a catalyst comprising 2%
platinum on alumina. In this hydrogenation step, which
The hydro?ned feed was then hydrogenated by passing
was consumptive of approximately 300 s.c.f. Hg/bbL, of
blending process.
10 feed, the feed was converted to an aromatics-free product.
Gravity, ‘’ API _____________________________ __ 47.1
Aniline point, °F __________________________ __
Para?ins, vol. percent _______________________ _Naphthenes, vol. percent ____________________ .__
Aromatics, vol. percent _____________________ __
The hydrogenated product was then hydrocracked by
ASTM distillation D-l58, ° F.:
passage, along with 6500 s.c.f. Hz/bhh, over the hydro
cracking catalyst shown in Example III hereof at 1200
p.s.ig., 480° F. and 0.8 LHSV. The portion of the e?lu
15 ent from the hydrocracking zone boiling above 525° F.
was recycled to said zone, and the e?luent portion boiling
below 525° F., obtained in a per-pass yield of 57.7%,
10% __________________________________ __ 238
had the following composition:
30% __________________________________ __ 255
Wt. percen
70% __________________________________ __ 319
90% __________________________________ -s 361
C1 ________________________________________ __
C2 ________________________________________ __ 0.05
End point _____________________________ __ 408
C3 ________________________________________ __
i-C4 ______________________________________ ..
In this operation light catalytic cycle oil of California
n-C4 ______________________________________
F. cut ____________________________ __ 10.6
180-360° F. cut ___________________________ __ 39.6
360-525° F. cut ___________________________ __ 44.4
origin lboiling over a range of 410 to 549° F. and, con
taining 900 p.p.m. total nitrogen and 55 volume percent
aromatics, was hydro?ned in the general manner shown
The feed and the above cuts had the following inspec
in Example II to reduce the total nitrogen content to 2.1 30 tions:
ppm. The resulting product, along with 12,000 s.c.f.
H2 per barrel of feed, was then passed at a pressure of
1200 p.s.i.g. and a LHSV of 3.0, ?rst over one and then
over another of separate catalysts. The ?rst of said beds
Feed Cir-180° F. } ISO-360° F. ‘BSD-525° F.
contained the hydrogenating catalyst shown in Example
Gravity, ° API ________ __
34. 0
Aniline point, ° F _____ __
II, and the feed stream was admitted thereto at a tem
Parai?ns, Vol. percent..Naphthenes, Vol. per
cent _________________ _-
perature of approximately 500° F. The total e?luent
84. 4 est.
__________ _-
39. 9
__________ __
Aromatics, Vol. percent..
stream from said bed, now at a temperature of approxi
Freezing point, ° F ____________________________________ _—27
mately 670° F. due to the exothermic nature of the hydro
Smoke point, mm ______________________________________ __
genation reaction taking place over the catalyst, was 40
then passed over the catalyst in the second bed, said
In addition to the advantages discussed above and ob
catalyst being a hydrocracking catalyst having the same
tained by a practice of this invention, it may also be ob
composition as that of Example II. This operation was
served that hydrogenating the feed prior to hydrocrack
conducted once-through, and resulted in a 59.7% per
ing the same permits the hydrocracking zone to be op
pass conversion of the feed to synthetic product boiling 45 erated at signi?cantly lower pressures than would other
below 360° F. Based on total feed to the reactor, a
wise be the case, this without any increase in the fouling
product stream was obtained having the following com
rate. Thus, for example, it has been found that by satu
rating the aromatics present therein, a typical catalytic
Wt. percent 50 cycle stock can be hydrocraclted at pressures of from
about ‘600 to 800 p.s.ig. without raising the catalyst foul
C, ________________________________________ __
C: ________________________________________ __ 0.06
C3 ________________________________________ __
i-Ci ______________________________________ __
l'l-Cq ______________________________________ __
ing rate over that otherwise obtained from pressures of
about 1200-1500 p.s.ig in operations conducted without
preliminary saturation of the aromatics in the feed prior
to hydrocracking.
C5--180° F. cut ___________________________ .. 13.4
180—360° F. cut ____________________________ __ 42.5
360° F.+ cut _____________________________ __ 38.1
tillate feed boiling above about 300° F., and containing
nitrogen compounds and 1 to 100 volume percent of
aromatic compounds, to produce superior quality fuel
The respective cuts shown above had the following in
(Dr-180° F.
ISO-360° F.
Gravity, ° API _______________ __
Aniline point, ° F _________________________ __
50. 7
121. 5
38. 8
149. 5
V 01 .
Aromatics, V01 percon
__ ________________________ __
Smoke point, mm _______________________________________ __
Freezing point, °
._ _.
products, which comprises:
a. hydro?ning said feed by contacting said feed and
at least 500 s.c.f. of hydrogen per barrel thereof
360° F. °
percent ____________ __
We claim:
1. A process for the conversion of a hydrocarbon dis
with a sulfur-resistant hydro?ning catalyst at a tem
perature of from about 450° to 800“ R, a pressure
of at least 300 p.s.i.g., and a liquid hourly space ve
locity of from about 0.3 to 50 whereby the nitrogen
content of said feed is substantially reduced, with no
more than a minor amount of aromatics saturation.
b. passing the resulting hydro?ned product and at least
In this operation a heavy catalytic cycle oil of Cali
fornia origin boiling from 3810 to 783° F. and containing
900 ppm. total nitrogen was hydro?ned to a nitrogen
level of 0.2 ppm. by passage, at 745‘I F., 1200 p.s.i.g., 75
2000 s.c.f of hydrogen per barrel thereof into con
tact with an aromatics hydrogenation catalyst at a
temperature of from about 300° to 700° F., a pres
sure of at least 300 p.s.i.g., and a liquid hourly space
velocity of about 0.3 to 50, whereby at least 50%
of the aromatics present are saturated.
0. passing the resulting hydro?ned and hydrogenated
in the aromatics-saturation step is about from 400° to
product and at least 500 s.c.f. of hydrogen per barrel
650° F.
of total feed into contact with a hydrocracking cata
4. A process as in claim 2, wherein the temperature
lyst at a temperature of from about 350° to 700°
in the aromatics~saturation step is about from 400° to
F. and a pressure of at least 400 p.s.i.g., whereby 5 650° F.
at least 50 volume percent of the resulting hydro
References Cited in the ?le of this patent
cracked products boil below the initial boiling point
of the feed, and
d. recovering from the hydrocracking step a product
Voorhies et al. _______ __ Sept. 28, 1948
Smith ______________ __ Jan. 18, 1949
normal para?ins that is higher than the theoretical
Hemminger et a1 ______ __ Dec. 21, 1954
thermodynamic equilibrium ratio.
Hennig ______________ __ Dec. 20, 1955
Kirshenbaum ________ __ Apr. 28, 1959
Burton et a1 __________ __ May 26, 1959
Ciapetta ____________ __ Nov. 24, 1959
Ciapetta et a1. ________ __ July 19, 1960
Folkins _____________ __
Kirshenbaum et al _____ __
Archibald ___________ __
Hansford et al ________ __
characterized by a low aromatics content, a high
naphthene content, and a ratio of isoparat?ns to
2. A process as in claim 1 wherein said hydrocarbon
distillate feed contains in excess of 10 ppm. total N, 15
the nitrogen content is reduced in the hydro?ning step
to less than 10 ppm. total nitrogen, and the resulting
hydro?ned product is contacted in the aromatics hy
drogenation step with an alumina supported platinum
aromatics-saturation catalyst.
3. A process as in claim 1 wherein the temperature
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