Note: Descriptions are shown in the official language in which they were submitted.
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BULK Ni-Mo-W CATALYSTS MADE FROM
PRECURSORS CONTAINING AN ORGANIC.AGENT
FIELD OF THE INVENTION
[0001] This invention relates to bulk tri-metallic catalysts for use in the
hydroprocessing of hydrocarbon feeds, as well as a method for preparing such
catalysts. The catalysts are prepared from a catalyst precursor containing an
organic agent.
BACKGROUND OF THE INVENTION
[00021 Environmental and regulatory initiatives are requiring ever-lower
levels
of both sulfur and aromatics in distillate fuels. For example, proposed sulfur
limits for distillate fuels to be marketed in the European Union for the year
2005
is 50 wppm or less. There are also regulations that will require lower levels
of
total aromatics in hydrocarbons and, more specifically, to lower levels of
multiring aromatics found in distillate fuels and heavier hydrocarbon
products.
Further, the maximum allowable aromatics level for U.S. on-road diesel, CARB
reference diesel, and Swedish Class I diesel are 35, 10 and 5 vol.%,
respectively.
Further, the CARB and Swedish Class I diesel fuel regulations allow no more
than
1.4 and 0.02 vol.% polyaromatics, respectively. Consequently, much work is
presently being done in the hydrotreating art because of these proposed
regulations.
[0003] Hydrotreating, or in the case of sulfur removal, hydrodesulfurization,
is
well known in the art and typically requires treating the petroleum streams
with
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hydrogen in the presence of a supported catalyst at hydrotreating conditions.
The
catalyst is usually comprised of a Group VI metal with one or more Group VIII
metals as promoters on a refractory support, such as alumina. Hydrotreating
catalysts that are particularly suitable for hydrodesulfurization, as well as
hydrodenitrogenation, generally contain molybdenum or tungsten on alumina
promoted with a metal such as cobalt, nickel, iron, or a combination thereof.
Cobalt
promoted molybdenum on alumina catalysts are most widely used when the
limiting
specifications are hydrodesulfurization. Nickel promoted molybdenum on alumina
catalysts are the most widely used for hydrodenitrogenation, partial aromatic
saturation, as well as hydrodesulfurization.
[0004] One approach to prepare improved hydrotreating catalysts involved a
family of phases structurally related to hydrotalcites and derived from the
parent
ammonium nickel molybdate. Whereas X-ray diffraction analysis has shown that
hydrotalcites are composed of layered phases with positively charged sheets
and
exchangeable anions located in the galleries between the sheets, the related
ammonium nickel molybdate phase has molybdate anions in interlayer galleries
bonded to nickel oxyhydroxide sheets. See, for example, Levin, D., Soled, S.
L.,
and Ying, J. Y., "Crystal Structure of an Ammonium Nickel Molybdate prepared
by Chemical Precipitation," Inorganic Chemistry, Vol. 35, No. 14, p. 4191-4197
(1996). The preparation of such materials also has been reported by Teichner
and
Astier, Appl. Catal. 72, 321-29 (1991), Ann. Chim. Fr. 12, 337-43 (1987), and
C.
R. Acad. Sci. 304 (II), #11, 563-6 (1987) and Mazzocchia, Solid State Ionics,
63-
65 (1993) 731-35.
100051 Another relatively new class of hydrotreating catalysts is described in
U.S. Patent Nos. 6,156,695, 6,162,350 and 6,299,760, all of which are
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incorporated herein by reference. The catalysts described in these patents are
bulk
multi-metallic catalysts comprised of at least one Group VIII non-noble metal
(X)
and at least two Group VIB metals, wherein the ratio of Group VIB metal to
Group VIII non-noble metal is from 10:1 to 1:10. These catalysts are prepared
from a precursor having the formula:
(X)b (Mo)c (W)d Oz
wherein the molar ratio of b:(c+d) is 0.5/1 to 3/1, the molar ratio of c:d is
>0.01/1,
preferably >0.1/1 and z = [2b + 6 (c+d)]/2. The precursor has x-ray
diffraction
peaks at d = 2.53 and 1.70 Angstroms. The precursor is sulfided to produce the
corresponding activated catalyst.
[0006] While such catalysts have proven to be superior to hydrotreating
catalyst before their time, there still remains a need in the art for ever-
more
reactive and effective catalysts for removing heteroatoms, such as nitrogen
and
sulfur from hydrocarbon streams.
SUMMARY OF THE INVENTION
[0007] In an embodiment, there is provided a bulk multi-metallic catalyst
composition represented by the formula:
(X)a (Moi-XWX)b[(CH3CH2)dN(CH3)3 ]eOz
wherein X is one or more Group VIII non-noble metals, d is an integer from 10
to
40, x is between 0 and 1, the molar ratio of e:a is <_ 2.0/1 and z = ((2a+6b)+
e)/2
and the molar ratio of a: (b) is 0.5/1 to 3/1; and wherein said catalyst after
sulfidation, is comprised of stacked layers of (MoI-,,W,)SZ stoichiometry,
such that
the average stack height is 10A to 20A.
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100081 In a preferred embodiment, the molar ratio of a:b is from 0.75/1 to
1.5/1, and d is from 16 to 20, most preferably 18, and e is between 0.5 and
1.5.
[0009] In a preferred embodiment of the present invention, x is between 0.1
and 0.9, more preferably 0.5.
BRIEF DESCRIPTION OF DRAWINGS
[0010] Figure 1 shows X-ray diffraction patterns of a Ni 1.5 Mo .5 W .5 -
oxide phase (top trace) prepared according to Example 1 hereof and the
catalyst
precursor NiMo.5W.5[CH3(CHZ) N(CH3)3]0.75-oxide phase (bottom trace) in
accordance with Example 2 hereof.
[0011] Figure 2 shows X-ray diffraction patterns of a Nil.5Mo.5W.5-sulfided
(top trace), and the bottom trace being NiMo.5W.5[(CH2)18]0.75-sulfided
(bottom
trace) both of Example 3 hereof.
[0012] Figure 3a is a transmission electron micrograph of a prior art Ni-Mo-W-
sulfided catalyst prepared from an oxide precursor as taught in U.S. Patent
No.
6,156,695 showing a stack height of 45A (7-8 sheets).
[0013] Figure 3b is a transmission electron micrograph of the Ni-Mo-W-
sulfided catalyst of the present invention prepared from an organic agent
(amine
surfactant) method of the present invention showing a stack height of 15A (2.5
sheets).
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[0014] Figure 4 is a plot of the TG/MS data obtained in Example 5 hereof and
evidences the formation of carbosulfide crystallites prepared by the organic
agent
method of Example 2 hereof versus the crystallite formed in accordance with
the
prior art neat oxide method of Example 1 hereof.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The bulk multi-metallic catalyst compositions of the present invention
can be used in virtually all hydroprocessing processes to treat a plurality of
feeds
under wide-ranging reaction conditions such as temperatures from 200 C to
450 C, hydrogen pressures from 5 to 300 bar (500 to 30,000 kPa), liquid hourly
space velocities from 0.05 to 10 h-' and hydrogen treat gas rates from 35.6 to
1780
m3/m3 (200 to 10,000 SCF/B). The term "hydroprocessing" encompasses all
processes in which a hydrocarbon feed is reacted with hydrogen at the
temperatures and pressures noted above, and includes hydrodemetallation,
hydrodewaxing, hydrotreating, hydrogenation, hydrodesulfurization,
hydrodenitrogenation, hydrodearomatization, hydroisomerization, and
hydrocracking including selective hydrocracking. Depending on the type of
hydroprocessing and the reaction conditions, the products of hydroprocessing
may
show improved viscosities, viscosity indices, saturates content, low
temperature
properties, volatilities and depolarization. It is to be understood that
hydroprocessing of the present invention can be practiced in one or more
reaction
zones and in either countercurrent flow or cocurrent flow mode. By
countercurrent flow mode we mean a process mode wherein the feedstream flows
countercurrent to the flow of hydrogen-containing treat gas. The
hydroprocessing
reactor can also be operated in any suitable catalyst-bed arrangement mode.
For
example, it can be a fixed bed, slurry bed, or ebulating bed.
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[0016] A wide range of petroleum and chemical feedstocks can be
hydroprocessed in accordance with the present invention. Suitable feedstocks
include whole and reduced petroleum crudes, atmospheric and vacuum residua,
propane deasphalted residua ,e.g., brightstock, cycle oils, FCC tower bottoms,
gas
oils, including atmospheric and vacuum gas oils and coker gas oils, light to
heavy
distillates including raw virgin distillates,hydrocrackates, hydrotreated
oils,
dewaxed oils, slack waxes, Fischer-Tropsch waxes, raffinates, naphthas, and
mixtures thereof.
[0017] The instant invention can be practiced in one or more stages or zones.
In one preferred multistage process, a distillate boiling range feedstock
containing
high levels of sulfur and nitrogen can be conducted to a first
hydrodesulfurization
reaction stage for the removal of a substantial amount of the sulfur and
nitrogen.
Suitable feeds are those containing in excess of 3,000 wppm sulfur and are
typically raw virgin distillates. The product stream is passed to a separation
zone
wherein a vapor phase product stream and a liquid phase product stream are
produced. The liquid phase product stream is then passed to a second,
independently selected hydrodesulfurization stage, which also contains one or
more reaction zones, where it is further hydrodesulfurized in the presence of
hydrogen and a second hydrodesulfurization catalyst. This will typically
result in
a product stream containing from 50 to 600 wppm sulfur. It is preferred that
the
product stream contain from the second hydrodesulfurization stage contain.less
than 150 wppm sulfur, more preferably less than 100 wppm sulfur, and most
preferably less than 50 wppm sulfur. This twice hydrodesulfurized product
stream will be passed to a third reaction stage and be reacted in the presence
of
hydrogen and a catalyst capable of further reducing the sulfur level and
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hydrogenating aromatics. The sulfur level of the final product stream will be
less
than 10 wppm, preferably less than 5 wppm, and more preferably less than 1
wppm sulfur. This third reaction stage will contain, at least one reaction
zone, at
least one of which contains a hydrogenation catalyst and, optionally, a third
independently selected hydrodesulfurization catalyst, such as the bulk multi-
metallic catalyst of the present invention. It is within the scope of this
invention
that at least a portion of the vapor product stream from either or both
reaction
stages can be recycled to the first reaction stage.
[0018] At least one of the reaction zones of at least one of the reaction
stages
will contain at least one bed of the bulk multi-metallic catalyst of the
present
invention. For example, the reactor of the first hydrodesulfurization stage
can
contain a plurality of reaction zones in a stacked bed arrangement wherein a
conventional hydrodesulfurization catalyst comprises one or more, but not all,
reaction zones and the bulk multi-metallic catalyst of the present invention
comprises the other one or more reaction zones. It is preferred that a
conventional
hydrodesulfurization catalyst be used in an upstream reaction zone and a multi-
metallic catalyst of the present invention be used in a downstream reaction
zone.
It is more preferred that all of the reaction zones of this first
hydrodesulfurization
stage contain the bulk multi-metallic catalyst of this invention.
[0019] Non-limiting examples of conventional hydrotreating catalysts that can
be used in the practice of the present invention along with the bulk multi-
metallic
catalyst include those that are comprised of at least one Group VIII metal,
preferably Fe, Co or Ni, more preferably Co and/or Ni, and most preferably Co;
and at least one Group VI metal, preferably Mo or W, more preferably Mo, on a
relatively high surface area support material, preferably alumina. Other
suitable
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hydrodesulfurization catalyst supports include zeolites, amorphous silica,
silica-
alumina, and titania-alumina Noble metal catalysts can also be employed,
preferably when the noble metal is selected from Pd and Pt. It is within the
scope
of the present invention that more than one type of hydrodesulfurization
catalyst
be used in the same reaction vessel. The Group VIII metal is typically present
in
an amount ranging from 2 to 20 wt.%, preferably from 4 to 12 wt.%. The Group
VI metal will typically be present in an amount ranging from 5 to 50 wt.%,
preferably from 10 to 40 wt.%, and more preferably from 20 to 30 wt.%. All
metals weight percents are on support. By "on support" is meant that the
percents
are based on the weight of the support. For example, if the support were to
weigh
100 grams, then 20 wt.% Group VIII metal would mean that 20 grams of Group
VIII metal was on the support.
[0020] In another embodiment, a two-stage process is used wherein the
feedstock to the first reaction stage will be the same feedstock as for the
three
reaction stage process, except that the product stream from the first stage
will
contain 300 to 1,500 wppm, preferably from 300 to 1,000 wppm, and more
preferably from 300 to 750 wppm sulfur. The second reaction stage will then
preferably contain both the bulk multi-metallic catalyst of this invention as
well as
an aromatic hydrogenation catalyst. The final product stream will contain less
than 30 wppm, preferably less than 20 wppm sulfur and a substantially lower
level
of aromatics.
100211 Non-limiting examples of aromatic hydrogenation catalysts that can be
used in the practice of the present invention include nickel, cobalt-
molybdenum,
nickel-molybdenum, and nickel tungsten. Non-limiting examples of noble metal
catalysts include those based on platinum and/or palladium, which is
preferably
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supported on a suitable support material, typically a refractory oxide
material such
as alumina, silica, alumina-silica, kieselguhr, diatomaceous earth, magnesia,
and
zirconia. Zeolitic supports can also be used. Such catalysts are typically
susceptible to sulfur and nitrogen poisoning. The aromatic saturation zone is
preferably operated at a temperature from 40 C to 400 C, more preferably from
260 C to 350 C, at a pressure from 100 psig (791 kPa) to 3,000 psig (20,786
kPa),
preferably from 200 psig (1,480 kPa) to 1,200 psig (8,274 kPa), and at a
liquid
hourly space velocity (LHSV) of from 0.3 V/V/Hr. to 2.0 V/V/Hr.
[0022] The preferred bulk trimetallic catalyst precursor compositions used in
the practice of the present invention is represented by the formula:
(X)a (Moi-XWX)n[(CH3CH2)aN(CH3)3 ]e0Z
wherein X is one or more Group VIII non-noble metals, d is an integer from 10
to
40, x is between 0 and 1, the molar ratio of e:a is <_ 2.0/1 and z = ((2a+6b)+
e)/2
and the molar ratio of a: (b) is 0.5/1 to 3/1; and wherein said catalyst after
sulfidation, is comprised of (MoI-XWX)S2 stacked layers, such that the average
stack height is 10A to 20A.
[0023] In a preferred embodiment, the molar ratio of a:b is from 0.75/1 to
1.5/1
and d is from 16 to 20, most preferably 18 and e is between 0.5 and 1.5.
[0024] In a preferred embodiment of the present invention, x is between 0.1
and 0.9, more preferably 0.5.
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[0025] Prior art catalysts, such as those taught in U.S. Patent Nos.
6,156,695,
6,162,350 and 6,299,760 teach the preparation of catalysts similar to those of
the
instant invention, but are prepared from oxides not containing an organic
agent,
(X)a (Mo)n (W), OZ
wherein the molar ratio of b, c, and d, are such that 0. 1 <(b+c)/a< 10, and
z=[2a +
6 (b+c)]/2. The precursor has x-ray diffraction peaks at d = 2.53 and 1.70
Angstroms.
[0026] This invention is based, in part, on the discovery that catalysts
prepared
using an organic agent precursor composition of the present invention results
in a
final catalyst uniquely different than those prepared using the oxide
precursor
without an organic agent. For example, the preparation of such catalysts
without
the organic agent, after activation by sulfidation, results in active sulfide
phase
crystallites having a normal [(Mo,W)Sz] layer structure having a stack height
of
45A (7 to 8 layers) and a crystallite diameter of 50A. On direct sulfidation
with a
non-carbon containing sulfidation media (i.e., H2S/H2), the organic agent Ni-
Mo-
W phase appears to produce a carbosulfide rather than a sulfide phase as those
catalysts prepared without the use of an organic agent. The supported
carbosulfide phase is unexpectedly more active for hydrodesulfurization than
prior art bulk tri-metallic bulk catalysts. The sulfided catalyst of the
present
invention that are prepared using the organic agent-containing precursor
results in
a carbosulfide phase with substantially smaller stack height (15A).
[0027] The organic agent R is selected from the group consisting of aromatic
amines, cyclic aliphatic amines and polycyclic aliphatic amines, preferably
aromatic amines such as C4 to C20 aromatic amines, e.g., pyrrolidine.
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[0028] The organic directing agent R for use in the above method for
synthesizing the present material from the reaction mixture is an ammonium or
phosphonium ion of the formula R, R2 R3 R4 Q+, i.e.:
R1
+
R~-Q R2
(
R3
wherein Q is nitrogen or phosphorus and wherein at least one of Ri, R2, R3 and
R4
is aryl or alkyl of from 8 to 36 carbon atoms, e.g., -C1 o H2 1, -C16 H33 and -
CI$ H37,
or combinations thereof, the remainder of Rl, R2, R3 and R4 being selected
from
the group consisting of hydrogen, alkyl of from 1 to 5 carbon atoms and
combinations thereof. Non-limiting examples of these directing agents suitable
for
use herein include cetyltrimethylammonium, cetyltrimethylphosphonium,
octadecyltrimethylphosphonium, cetylpyridinium, myristyltrimethylammonium,
decyltrimethylammonium, dodecyltrimethylammonium and
dimethyldidodecylammonium. The compound from which the above ammonium
or phosphonium ion is derived may be, for example, the hydroxide, halide,
silicate, or mixtures thereof.
100291 The preferred method of preparing the catalysts used in the practice of
the present invention comprises preparing a solution of all precursor
components
then heating the solution resulting in a precipitate to form a precursor
catalyst
composition. It is particularly preferred to make a solution of an ammonium
salt
of a Group VIB metal and a solution of a Group VIII non-noble metal nitrate.
Both solutions are heated to a temperature of 60 C to 150 C, preferably 90 C,
an
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organic agent, such as an amine surfactant, is added to the Group VIB metal
solution. The pressure will be from atmospheric to autogenous. The Group VIII
non-noble metal solution is added to the Group VIB metal solution and direct
precipitation of the Group VIB and Group VIII non-noble metal components
occurs. This synthesis can also be conducted at lower temperature and/or
decreased pressure or higher temperature and/or increased pressure. Suitable
Group VIB and Group VIII non-noble metal components are water-soluble nickel,
molybdenum and tungsten components. If soluble salts are added as such, they
will dissolve or disperse in the reaction mixture and subsequently be
precipitated.
Suitable Group VIB metal salts which are soluble in water are preferably
ammonium salts such as ammonium dimolybdate, ammonium tri-, tetra- hepta-,
octa-, and tetradeca- molybdate, ammonium para-, meta-, hexa-, and
polytungstate, alkali metal salts, silicic acid salts of Group VIB metals such
as
molybdic silicic acid, molybdic silicic tungstic acid, tungstic acid,
metatungstic
acid, pertungstic acid, heteropolyanion compounds of Mo-P, Mo-Si, W-P, and W-
Si. It is also possible to add Group VIB metal-containing compounds which are
not in solution at the time of addition, but where solution is effected in the
reaction mixture. Examples of such compounds are metal compounds that contain
so much crystal water that upon temperature increase they will dissolve in
their
own metal water. Further, non-soluble metal salts may be added in suspension
or
as such, and solution is effected in the reaction mixture. Suitable non-
soluble
metals salts are heteropolyanion compounds of Co-Mo-W (moderately soluble in
cold water) and heteropolyanion compounds of Ni-Mo-W (moderately soluble in
cold water).
100301 Precipitation can be effected by adding a Group VIII non-noble metal
salt solution to the Group VIB metal solution in the presence of the amine
organic
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agent and heating the mixture to effectuate the precipitation. The precipitate
obtained by this process will have, after sulfidatiori, a relatively high
catalytic
activity relative to conventional hydroprocessing catalysts, which typically
comprise a carrier impregnated with Group VIII non-noble metals and Group VIB
metals. For purposes of this invention, the precipitate is used without a
support.
Unsupported catalyst compositions are usually referred to as bulk catalysts.
[0031] The bulk catalyst precursor composition of the present invention can
generally be directly formed into various catalyst shapes depending on the
intended commercial use. These shapes can be made by any suitable technique,
such as by extrusion, pelletizing, beading, or spray drying. If the amount of
liquid
of the bulk catalyst composition is so high that it cannot be directly
subjected to a
shaping step, a solid-liquid separation can be performed before shaping.
Optionally, the bulk catalyst composition, either as such or after solid-
liquid
separation, can be calcined before shaping.
[0032] The median diameter of the bulk catalyst precursor particles is at
least
50 m, more preferably at least 100 m, and preferably not more than 5000 m
and more preferably not more than 3000 m. Even more preferably, the median
particle diameter lies in the range of 0.1 to 50 m and most preferably in the
range
of 0.5 to 50 m.
[0033] Binder material can be used in the preparation of the catalyst
precursor
composition it including material that is conventionally used as a binder in
hydroprocessing catalysts. Non-limiting examples of suitable binder materials
include silica, silica-alumina, such as conventional silica-alumina, silica-
coated
alumina and alumina-coated silica, alumina such as (pseudo) boehmite, or
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gibbsite, titania, zirconia, cationic clays or anionic clays such as saponite,
bentonite, kaoline, sepiolite or hydrotalcite, or mixtures thereof. Preferred
binder
materials are silica, silica-alumina, alumina, titanic, zirconia, or mixtures
thereof.
These binders may be applied as such or after peptization. It is also possible
to
apply precursors of these binders that, during precursor synthesis, are
converted
into any of the above-described binders. Suitable precursors are, e.g., alkali
metal
aluminates (to obtain an alumina binder), water glass (to obtain a silica
binder), a
mixture of alkali metal aluminates and water glass (to obtain a silica alumina
binder), a mixture of sources of a di-, tri-, and/or tetravalent metal such as
a
mixture of water-soluble salts of magnesium, aluminum and/or silicon (to
prepare
a cationic clay and/or anionic clay), chlorohydrol, aluminum sulfate, or
mixtures
thereof.
100341 If desired, the binder material can be composited with a Group VIB
metal and/or a Group VIII non-noble metal, prior to being composited with the
bulk catalyst composition and/or prior to being added during the preparation
thereof. Compositing the binder material with any of these metals may be
carried
out by impregnation of the solid binder with these materials. Those having
ordinary skill in the art would know suitable impregnation techniques. If the
binder is peptized, it is also possible to carry out the peptization in the
presence of
Group VIB and/or Group VIII non-noble metal components.
[0035] If alumina is used as binder, the surface area will preferably be in
the
range of 100 to 400 mZ/g, and more preferably 150 to 350 m2/g, measured by the
B.E.T. method. The pore volume of the alumina is preferably in the range of
0.5
to 1.5 ml/g measured by nitrogen adsorption.
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[0036] Generally, the binder material to be used has less catalytic activity
than
the bulk catalyst composition or no catalytic activity at all. Consequently,
by
using a binder material, the activity of the bulk catalyst composition may be
reduced. Therefore, the amount of binder material to be used will generally
depends on the desired activity of the final catalyst composition. Binder
amounts
from 0 to 95 wt.% of the total composition can be suitable, depending on the
envisaged catalytic application. However, to take advantage of the resulting
unusual high activity of the composition of the present invention, binder
amounts
to be added are generally in the range of 0.5 to 75 wt.% of the total
composition.
[0037] Prior to or during shaping, additives can be used to facilitate
shaping,
including conventional shaping additives. These additives may comprise
aluminum stearate, surfactants, graphite or mixtures thereof. These additives
can
be added at any stage prior to the shaping step. Further, when alumina is used
as
a binder, it may be desirable to add acids prior to the shaping step such as
nitric
acid to increase the mechanical strength of the extrudates.
[0038] It is preferred that a binder material, if used, be added prior to the
shaping step. Further, it is preferred that the shaping step is carried out in
the
presence of a liquid, such as water. Preferably, the amount of liquid in the
extrusion mixture, expressed as LOI is in the range of 20 to 80%.
[0039] The resulting shaped catalyst precursor composition can, after an
optional drying step, be calcined. Calcination however is not essential for
precursor synthesis. If a calcination is carried out, it can be done at a
temperature
of, e.g., from 100 C to 600 C and preferably 350 C to 500 C for a time varying
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from 0.5 to 48 hours. The drying of the shaped particles is generally carried
out at
temperatures above 100 C.
[0040] In a preferred embodiment of the invention, the catalyst precursor
composition is subjected to spray drying, (flash) drying, milling, kneading,
or
combinations thereof prior to shaping. These additional process steps can be
conducted either before or after a binder is added, after solid-liquid
separation,
before or after calcination and subsequent to re-wetting. It is believed that
by
applying any of the above-described techniques of spray drying, (flash)
drying,
milling, kneading, or combinations thereof, the degree of mixing between the
bulk
catalyst composition and the binder material is improved. This applies 'to
both
cases where the binder material is added before or after the application of
any of
the above-described methods. However, it is generally preferred to add the
binder
material prior to spray drying and/or any alternative technique. If the binder
is
added subsequent to spray drying and/or any alternative technique, the
resulting
composition is preferably thoroughly mixed by any conventional technique prior
to shaping. An advantage of, e.g., spray drying is that no wastewater streams
are
obtained when this technique is applied.
100411 A cracking component may be added during catalyst preparation.
When used, the cracking component will represent 0 to 80 wt.% of the final
catalyst, based on the total weight of the catalyst. The cracking component
may
serve, for example as an isomerization enhancer. Conventional cracking
components can be used, such as a cationic clay, an anionic clay, a zeolite
such as
ZSM-5, (ultra-stable) zeolite Y, zeolite X, ALPO's, SAPO's, amorphous cracking
components such as silica-alumina, or mixtures thereof. It is to be understood
that
some materials may act as a binder and a cracking component at the same time.
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For instance, silica-alumina may have at the same time a cracking and a
binding
function.
[0042] If desired, the cracking component may be composited with a Group
VIB metal and/or a Group VIII non-noble metal prior to being composited with
the bulk catalyst composition and/or prior to being added during the
preparation
thereof. Compositing the cracking component with any of these metals may be
carried out by impregnation of the cracking component with these materials.
[0043] Generally, the selection of particular cracking components, if any,
depends on the envisaged catalytic application of the final catalyst
composition.
A zeolite is preferably added if the resulting composition is applied in
hydrocracking or fluid catalytic cracking. Other cracking components such as
silica-alumina or cationic clays are preferably added if the final catalyst
composition shall be used in hydrotreating applications. The amount of
cracking
material that is added depends on the desired activity of the final
composition and
the application envisaged and thus may vary from 0 to 80 wt.%, based on the
total
weight of the catalyst composition.
100441 If desired, further materials can be added in addition to the metal
components already added, such as any material that would be added during
conventional hydroprocessing catalyst preparation. Suitable examples are
phosphorus compounds, boron compounds, fluorine-containing compounds,
additional transition metals, rare earth metals, fillers, or mixtures thereof.
[0045] Suitable phosphorus compounds include ammonium phosphate,
phosphoric acid, or organic phosphorus compounds. Phosphorus compounds can
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be added at any stage of the process of the present invention prior to the
shaping
step and/or subsequent to the shaping step. If the binder material is
peptized,
phosphorus compounds can also be used for peptization. For instance, the
binder
can be peptized by contacting the binder with phosphoric acid or with a
mixture of
phosphoric and nitric acid.
[0046] Suitable additional transition metals are, e.g., rhenium, ruthenium,
rhodium, iridium, chromium, vanadium, iron, cobalt, platinum, palladium,
cobalt,
nickel, molybdenum, or tungsten. These metals can be added at any stage of the
process of the present invention prior to the shaping step. Apart from adding
these metals during the process of the invention, it is also possible to
composite
the final catalyst composition therewith. It is, e.g., possible to impregnate
the
final catalyst composition with an impregnation solution comprising any of
these
metals.
[0047] Synthesis of the bulk catalyst compositions will comprise a precursor
sulfidation step. Sulfidation is generally carried out by contacting the
catalyst
precursor composition with a sulfur-containing compound such as elementary
sulfur, hydrogen sulfide or polysulfides. The sulfidation can generally be
carried
out subsequent to the preparation of the bulk catalyst composition but prior
to the
addition of a binder material, and/or subsequently to the addition of the
binder
material but prior to subjecting the catalyst composition to spray drying
and/or
any alternative method, and/or subsequently to subjecting the composition to
spray drying and/or any alternative method but prior to shaping, and/or
subsequently to shaping the catalyst composition. It is preferred that the
sulfidation not be carried out prior to any process step that reverts the
obtained
metal sulfides into their oxides. Such process steps are, e.g., calcination or
spray
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drying or any other high temperature treatment in the presence of oxygen.
Consequently, if the catalyst composition is subjected to spray drying and/or
any
alternative technique, the sulfidation should be carried out subsequent to the
application of any of these methods.
[0048] If the catalyst composition is used in a fixed bed process, the
sulfidation
is preferably carried out subsequent to the shaping step and, if calcination
is used,
subsequent to the last calcination step. Preferably, the sulfidation is
carried out ex
situ, i.e., the sulfidation is carried out in a separate reactor prior to
loading the
sulfided catalyst composition into the hydroprocessing unit. Furthermore, it
is
preferred that the catalyst composition is both sulfided ex situ and in situ.
100491 It has been found herein that the bulk catalyst particles of the
present
invention are sintering-resistant. Thus, the active surface area of the bulk
catalyst
particles is maintained during use. The molar ratio of Group VIB to Group VIII
non-noble metals ranges generally from 10:1 to 1:10 and preferably from 3:1 to
1:3. In the case of a core-shell structured particle, these ratios of course
apply to
the metals contained in the shell. If more than one Group VIB metal is
contained
in the bulk catalyst particles, the ratio of the different Group VIB metals is
generally not critical. The same holds when more than one Group VIII non-noble
metal is applied. In the case where molybdenum and tungsten are present as
Group VIB metals, the molybenum:tungsten ratio preferably lies in the range of
9:1 to 1:9. Preferably the Group VIII non-noble metal comprises nickel and/or
cobalt. It is further preferred that the Group VIB metal comprises a
combination
of molybdenum and tungsten. Preferably, combinations of
nickel/molybdenum/tungsten and cobalt/molybdenum/tungsten and
nickel/cobalt/molybdenum/tungsten are used. These types of precipitates appear
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to be sinter-resistant. Thus, the active surface area of the precipitate is
remained
during use.
100501 The metals are preferably present as oxidic compounds of the
corresponding metals, or if the catalyst composition has been sulfided,
sulfidic
compounds of the corresponding metals. Some of the carbonaceous components
of the organic agent remain in the catalyst after sulfiding. While not being
bound
by theory, the authors believe that the incorporation of the carbonaceous
material
into the sulfide intercepts the growth of the sulfide stacks during conversion
of the
oxide to the sulfide and results in lower stack height material.
[0051] The surface area of the catalyst composition preferably is at least 40
m 2/g, more preferably at least 80 m2/g and most preferably at least 120 m2/g,
as
measured by the B.E.T. method. The total pore volume of the catalyst
composition is preferably at least 0.05 ml/g and more preferably at least 0.1
ml/g
as determined by water porosimetry. To obtain catalyst compositions with high
mechanical strength, it may be desirable that the catalyst composition of the
invention has a low macroporosity. It is furthermore preferred that the
particles
comprise 50 to 100 wt.%, and even more preferably 70 to 100 wt.% of at least
one
Group VIII non-noble metal and at least one Group VIB metal, based on the
total
weight of the particles, calculated as metal oxides. The amount of Group VIB
and
Group VIII non-noble metals can easily be determined via TEM-EDX.
[0052] Process conditions applicable for the use of the catalysts described
herein may vary widely depending on the feedstock to be treated. Thus, as the
boiling point of the feed increases, the severity of the conditions will also
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increase. The following table serves to illustrate typical conditions for a
range of
feeds.
TABLE 1
FEED TYPICAL TEMP. PRESSURE, SPACE H2 GAS
BOILING C BARS VELOCITY RATE
RANGE C (kPa) V/V/HR SCF/B
m'/m3
Naphtha 25-210 100-370 10-60 0.5-10 100-2,000
(1,000-6,000) 17.8-356)
Diesel 170-350 200-400 15-110 0.5-4 500-6,000
(1,500-11,000) (89-1,068)
Heavy Gas 325-475 260-430 15-170 0.3-2 1,000-6,000
Oil (1,500-17,000) (178-1,068)
Lube Oil 290-550 200-450 6-210 0.2-5 100-10,000
(600-21,000) (17.8-1,780)
Residuum 10-50%>575 340-450 65-1,100 0.1-1 2,000-10,000
(6,500-110,000) (356-1,780)
[0053] The following examples will serve to illustrate, but not limit, this
invention.
EXAMPLES
Example 1
100541 28.8 grams of MoO3 (0.2 mole Mo) and 50.0 grams of tungstic acid
H2W04 (0.2 mole W) were slurried in 800 ml of water (suspension A) and heated
to 90 C. 70.6 grams of nickel hydroxycarbonate 2NiCO3*3Ni(OH)2*4H20 (0.6
mole of Ni) were suspended in 200 ml of water and heated to 90 C (suspension
B). Suspension B was slowly added to suspension A during a 60-minute period,
and the resulting mixture was maintained at 90 C for a period of 18 hours with
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continuous stirring. At the end of this time, the resulting suspension was
filtered
and the solids were dried at 120 C for 4-8 hours and calcined at 400 C. The
yield
was 99%, based on the calculated weight of all metal components having been
converted to their oxides. The X-ray spectrum for this bulk catalyst precursor
oxide composition is shown as the upper trace in Figure 1 hereof.
Example 2
[0055] A catalyst precursor of nominal composition Nil Mo.5W,5 oxide with
octadecytrimethylammonium incorporated therein was prepared as follows: into
500 cc of water, 17.65 grams of ammonium heptamolybdate (0.10 moles Mo) and
24.5 grams of ammonium metatungstate (0.10 moles W) was dissolved. To this
was added 58.9 grams of octadecyltrimethylammonium bromide (0.15 moles),
which gave a solution of pH 5.7. This solution was heated to 90 C and formed a
milky slurry. To this was added 58.15 grams of nickel nitrate (0.20 moles Ni)
that
had been first dissolved in 100 cc of additional water. The entire mixture was
then heated and stirred in a three-necked flask containing a reflux condensor
and
thermometer to 90 C and held at that temperature for one hour. The final pH
measured 4.2. After filtering and drying at 120 C, the resulting solid weighed
63.5 grams. The X-ray diffraction spectra of this precursor is shown as the
bottom trace in Figure 1 hereof.
Example 3
[0056] 4-6 grams of catalysts from Examples 1 and 2 hereof were dried at
120 C and placed in a quartz boat that was in turn inserted into a horizontal
quartz
tube and placed into a Lindberg furnace. While still at room temperature, a
flow
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of 200 cc/min 10% H2S/H2 was admitted for 15 minutes, then the temperature was
raised to 400 C in 45 minutes with the 10% H2S/H2 flowing at 200 cc/min. This
flow was continued for 2 hours at 400 C. The heat was then turned off and the
resulting catalyst was cooled in flowing HzS/Hz to room temperature and held
at
room temperature for 30 minutes under the same flow. Then 300 cc/min of
nitrogen was admitted for 30 minutes. After that, a 1% oxygen in helium
passivation gas was admitted at room temperature and flowed at 50 cc/min
overnight. The sample was then removed from the furnace. The resulting X-ray
diffraction spectra was measured on the two samples and are shown in Figure 2
hereof. The top trace is the sulfided neat oxide sample and the bottom trace
is the
sulfided oxide-amine surfactant (organic agent) precursor of Ni-Mo-W. It will
be
noted in this Figure 2 the broadening of the (002) peak (at 12 degrees) for
the
precursor containing the amine surfactant. This broadening usually occurs as a
result of a decrease in stacking height of the sulfide sheets.
Example 4
[00571 Samples of the sulfided precursors of Example 3 hereof were crushed
into pieces (less than 100 mm thick), dusted onto holey-carbon coated TEM
grids,
and examined in a bright field TEM imaging mode of a Phillips CM200F
instrument. 250-350 different crystals of the sulfided precursor were examined
and the stack heights counted and averaged. Figures 3a and 3b hereof show the
representative TEM micrographs of these stacks as well as the stack height
measurements. This TEM data evidences that the organic agent-containing
sulfide precursors (Figure 3b) give a lower stack height sulfide when compared
to
those prepared without the organic agent (Figure 3a).
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Example 5
[0058] 70 mg of the catalyst compositions from Example 3 were loaded into a
Mettler TGA 851 thermal balance, which was interfaced with a Balzers
Thermostar quadrupole mass spectrometer equipped with a secondary electron
multiplier. The catalyst compositions were heated at 4 C/min from room
temperature to 600 C in flowing air (50 cc/min) at one atmosphere total
pressure.
The MS signal in amps for the m/e fragments of 18 (H20), 44 (COZ) and 64 (SOz)
together with the weight change are plotted and shown in Figure 4 hereof. It
will
be noted in Figure 4 that the CO2 and SO2 peaks from the sulfided organic
agent
precursor simultaneously emit at 375 C. This indicates that the sulfided
organic
agent phase forms a carbosulfide. It will also be noted from Figure 4 that the
oxidation of the sulfide prepared from the oxide presursors have no COz
evolution
and that the sulfide peak oxidizes at significantly higher temperature than
the
carbosulfide. This suggests that again the size of the [carbo]sulfide
crystallite is
smaller on the catalysts prepared from the organic agent than for the neat
oxide
precursor.
Example 6
[0059) The hydrodesulfurization activity of the catalyst compositions of
Examples 1 and 2 hereof were evaluated on a commercial atmospheric distillate
containing 592 wppm sulfur, 100 wppm nitrogen at 650 psig (4,579 kPa), 625 F
and a 2 LHSV (liquid hourly space velocity). The results are shown in Table 2
below.
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TABLE 2
Sample # Composition Ni-Mo-W vol. K wt.K
21649-8 Ni1.5Mo.5W.5 rt 3 11 7.7
21893-87 NiMo.5W55(ODTA).75 9.0 10.0
ODTA = octadecyltrimethylammonium
[0060] The ODTA sample had approximately 35 wt.% of carbon following
sulfidation. The gravimetric rate constants (using first-order kinetics) have
been
corrected for the amount of Ni-Mo-W present in each sample. Consequently, the
data of the above table shows that the ODTA containing precursor produces a
more active catalyst for the weight of Ni-Mo-W that is charged to a reactor.
