Note: Descriptions are shown in the official language in which they were submitted.
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RESIDUAL OIL PROCESSING CATALYSTS
BACKGROUND OF THE INVENTION
This invention relates to a catalyst for hydro-
treatment and hydrodemetalation of hydrocarbonaceous
feedstocks. More particularly, this invention relates to
catalysts and catalyst supports fabricated from
halloysite.
Impurities such as metals, sulfur and nitrogen
are contained in hydrocarbonaceous materials including
crude oils, heavy oils, cracked oils, deasphalted oils,
residual oils, shale oils, coal and partially liquefied
coal and the like. These impurities are discharged into
the atmosphere when the hydrocarbon i8 burned, creating a
major source of pollution. They also tend to rapidly foul
catalysts used for processing of the hydrocarbon or treat-
ing the exhaust from combusted hydrocarbons. The removal
o these undesirable impurities as early as possible in
the processing of the hydrocarbonaceous materials is
therefore highly desirable.
When metals such as nickel, iron and vanadium
are present, they tend to deposit on the interior surface
of the pores of hydroprocessing catalysts, tending to plug
the pore mouths thereby reducing activity. It is desir-
able, therefore, that a substantial volume of the pores
have a pore mouth diameter greater than 200 Angstroms.
The majority of the pores should be preferably smaller
than about a 1000 Angstroms because large pores tend to
decrease the mechanical crush strength of the catalyst
bodies, and also decrease surface to volume ratios.
Catalysts that effectively trea~ asphaltene
containing fractions are desirable because many known
crude oil reserves worldwide are high in asphaltenes.
Additionally, various synthetic fuel processes tend to
create fractions high in asphaltenes.
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Catalysts containing clay materials have been
suggested for hydroprocessing heavy hydrocarbon feeds.
05 For example, U.S. Patent No. 4,152,250 to Inooka suggests
the use of a catalyst containing the mineral sepiolite
(Meershaum), a fibrous magnesium silicate clay and transi-
tion metals and/or Group II-B metals. Another clay which
has been suggested is halloysite. Halloysite is an
aluminum silicate clay that frequently occurs naturally in
a rod like form. The basic formula is A12Si2O5(OH)4-
In U.S. Patent No. 4,098,696, a synthesis of the
plate form of halloysite is disclosed. In U.S. Patent No.
3,891,541 a demetalation catalyst is disclosed that is
formed from halloysite and alumina. The pore structure
contains pores with a diameter of between about 180
Angstroms to about 300 Angstroms. The pore diameters are
said to be an artifact of the alumina.
SUMMARY OF THE INVENTION
This invention provides a method for the
hydroprocessing of hydrocarbonaceous feedstocks containing
asphaltenes. It also provides a catalyst and catalyst
support useful, for example, in hydroprocessing
hydrocarbonaceous feedstocks containing asphaltenes.
These and other objects are achieved in a porous
composition of matter having dispersed rods of halloysite
and from 0-15 percent by weight of a binder oxide. The
weight percentage is based on the total weight of both the
halloysite and the binder oxide.
In one embodiment of this invention a catalyst
is prepared by (a) preparing a mix of halloysite and a
fibrous second clay, halloysite having predominantly rods
having a length within the range of 0.5-2 microns and a
diameter within the range of 0.04-0.2 microns, and the
fibrous second clay having predominantly rods having a
length within the range of 1-5 microns and a diameter
within the range of 50-100 Angstroms, (b) adding suffi-
cient liquid to said mix to form a slurry of no more than
25 percent solid, and then vigorously agitating the slurry
to substantially disperse the rods, tc) removing enoùgh
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water from the slurry to form an easily shapable mass,
shaping the mass, and (d) drying and calcining the shaped
05 body. It is preferred that attapulgite be used as the
fibrous second clay.
In its composition of matter aspects, this
invention comprises c~dispersed rods of halloysite and a
fibrous second clay, halloysite composed predominantly of
fibers with a length range of 0.5-2 microns and a diameter
range of 0.04-0.2 microns and a fibrous second clay
predominantly composed of fibers having a length range of
1-5 microns and a diameter range of 50-100 Angstroms.
Halloysite must be in the tubular form. A preferred
second clay is fibrous attapulgite. It is preferred that
the composition be at least 5 percent attapulgite. It is
preferred that the binder oxide be alumina. It is
preferred that the catalyst body have a total pore volume
of at least 0.35 cc/g and at least 60 percent of the
volume of the pores is present in pores having diameters
of 200-700 Angstroms. This invention also comprises a
method for hydroprocessing hydrocarbonaceous feedstocks
comprising contacting the feedstocks with molecular
hydrogen under hydroprocessing conditions in the presence
of a catalyst having codispersed rods of halloysite having
rods predominantly in the range of 0~.5-2 microns with a
; diameter range of 0.04-0.2 microns and a fibrous second
clay having rods in the range of 1-~ microns and a
diameter range of S0-100 Angstroms.
It is preferred that the composition include at
least one catalytic transition metal preferably a metal
selected from Group VI-B or VIII of the Periodic Table.
It is preferred that the composition have a pore volume of
at least 0.35 cc/g of which at least 70 percent of the
pore volume is present in pores having a diameter of 200-
700 Angstroms and at least 70 percent of those pores have
diameters of 300-700 Angstroms. Hydrocarbon feedstocks
containing at least one percent by weight asphaltenes can
be processed by contacting feedstocks with hydrogen under
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hydroprocessing conditions in the presence of a catalyst
composition comprising dispersed rods of halloysite and
S between 0-15 weight percent of a binder oxide.
DETAILED DESCRIPTION
The catalyst composition of the present inven-
tion involves the rod form of halloysite processed alone
or in combination with a fibrous clay so that the rods are
dispersed. "Dispersed rods" are defined herein to mean
- rods of halloysite which have been substantially complete-
ly disassociated from one another and are substantially
randomly oriented with respect to one another.
The tubular or rod form of halloysite is readily
available from natural deposits. It frequently comprises
bundles of tubular rods or needles consolidated or bonded
together in a weakly parallel orientation. It has been
discovered that if these bundles of rods are broken up by
mechanical means and re-oriented in a substantially random
orientation with respect to one another, a catalyst sup-
port with superior asphaltene hydroconversion properties
results. Halloysite occurs naturally in tubular rods that
are approximately 1 micron long and 0.1 micron in diameter
with a centrally located hole penetrating the rod from
about 100 Angstroms to about 300 Angstroms in diameter
resulting in a scroll-like rod, in contrast to fibrous
- clays like attapulgite and sepiolite which are non-
tubular. The exact dimensions vary from rod to rod and
are not critical. It is critical that the rod form,
rather than the platy form, of halloysite be used.
When halloysite rods or other rods of similar
dimensions are agitated in a fluid such as water to
disperse the rods, the dispersion can be shaped, dried and
calcined to provide a porous body having a large pore
volume present as 200-700 Angstroms diameter pores. When
the shaping is by extrusion, however, it has been found
that mixtures of dispersed clay rods of the halloysite
type, do not extrude well. The rods on the surface of the
extruded bodies tend to realign, destroying the desirable
pore structure at the surface of the catalyst. This is
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01 _5_
defined herein as a "skin effect". It has been discov-
ered, however, that if a fibrous second clay with longer,
oS narrower and presumably more flexible, fibers is codis-
persed with the halloysite-type clay, the resulting
composition is easily extrudible, and there is no signi-
ficant skin effect. "Codispersed~ is defined herein as
having rod- or tube-like clay particles of at least two
distinct types substantially randomly oriented to one
another.
The second fibrous clay should have long slender
fibers typically about 1-5 microns in length with a
diameter range of about 50-100 Angstroms. Clays for use
as the second component include attapulgite, crysotile',
immogolite, palygorskite, sepiolite and the like.
In addition to the'halloysite component and the
second fibrous clay component of the present catalyst, an
inorganic binder oxide may be added to increase crush
strength. Inorganic binder oxides are defined as
refractory inorganic oxide such as, silica and oxides of
elements in Group 2a, 3b and 3a of the Periodic Table as
defined in Handbook of Chemistry and Physics, 45th
Edition. Preferable binder oxides include: silica,
alumina, magnesia, zirconia, titania, boria and the
like. An especially preferred binder oxide is alumina.
It has been discovered that the amount of asphaltene
adsorbed onto a catalyst support of dispersed rods of
halloysite is related to the amount of binder oxide
used. When the amount of binder oxide exceeds about 15
percent of the total weight of halloysite and binder
oxide, the amount of asphaltenes adsorbed is severely
reduced. It has been found that an especially preferable
amount of binder oxide is about 5 percent. As more binder
oxide is added to the catalyst support, the pore sizes
tend to cluster around smaller distributions. A catalyst
support with 25 percent alumina has substantially all of
its pores less than 100 Angstroms in diameter.
If an inorganic oxide component is to be present
into the composition of the present invention, codispersal
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of the rods of the fibrous clay is preferably carried out
in the presence of an aqueous hydrogel or the sol precur-
sor of the inorganic oxide gel component. The preferred
inorganic oxide is alumina. Mixtures of two or more
inorganic oxides are ~;uitable for the present invention
for example, silica and alumina.
A function of the inorganic oxide gel component
is to act as a bonding agent for holding or bonding the
clay rods in a rigid, three-dimensional matrix. The
resulting rigid skeletal framework provides a catalyst
body with high crush strength and attrition resistance.
A catalyst support made from halloysite alone or
in combination with a fibrous clay can contain any
catalytic reactive transition metal. The catalytic metal
component can be added during any stage of preparation.
Catalytic metals can be added as powdered salts or oxides
during the agitation stage or by impregnation of the
catalyst body by adding a metal containing solution after
the catalyst bodies have been formed. Preferred catalytic
metals are those of Groups VI-B and VIII of the Periodic
Table. When preparing hydroprocessing catalysts, it is
preferable that the composition include at least one metal
of the group of chromium, molybdenum, tungsten and
vanadium, and at least one metal of the group of iron,
nickel and cobalt, such as cobalt-molybdenum, nickel-
tungsten or nickel-molybdenum.
The metal component can be added to the catalyst
composition at any stage of the catalyst preparation by
any conventional metal addition step. For example, metals
or metal compounds can be added to the slurry as solids or
in solution, preferably before dispersion of the clay
rods. Alternatively, an aqueous solution of metal can
impregnate the dried or calcined bodies. The metals can
be present in reduced form or as one or more metal
compounds such as oxides or sulfides. One preferred
method is impregnating the calcined catalyst bodies with a
solution of phosphomolybdic acid and nickel nitrate.
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01 _7_
Preparation of the catalyst with dispersed rods
is accomplished by creating a mi~ture of tubular halloy-
05 site a fibrous second clay and if desired, binder oxideand enough water to form a slurry of about 20 weight
percent solid content~ As the mixture is violently
agitated the slurry i5 observed to thicken. Agitation is
continued until the slurry stops thickening with continued
agitation. This takes about l0 minutes of agitation.
This thickening is indicative of dispersal of the rods.
Excess water in the slurry is removed by evaporation until
a moldable plastic mass is formed. The bodies are then
shaped by spheridizing, pelletizing and similar procedures
and then calcined. It has been observed that a catalyst
body made e~clusively of dispersed rods of halloysite
tends not to extrude well. The rods tend to realign on
the surface of the extruded mass, and this skin effect
decreases the average pore diameter at the surface of the
extruded mass. Alternatively, the halloysite mass can be
dried and calcined; and the calcined mass broken up to
produce cataly~t bodies. The final product is a catalyst
body with the characteristics of dispersed rods of
halloysite. It is preferable that the binder oxide be
added to the halloysite as the gel or the sol precursor to
the gel at the agitation stage of the slurry.
Referring to Table I, the pore size distribution
for unprocessed halloysite and pore size distribution for
halloysite with dispersed rods are compared. It will be
noted that in unprocessed halloysite most of the pore size
is in the 200-400 Angstrom range. On the other hand,
halloysite with dispersed rods has most of its pores
distributed from 400-600 Angstroms. In halloysite with
dispersed rods there is a substantial amount of pore
volume provided by pores having diameters in the range of
l00-300 Angstroms. It is believed that these pores are
from the central hole present in halloysite rods. The
presence of these smaller pores is not a gauge of the
thoroughness of dispersion of the rods.
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TABLE I
Pore Size Distribution
05(Expressed as percentage of Total Pore Volume)
With
Pore Size DiameterUnprocessedDispersed Rods
>600 Angstroms 4% < 1~
500-600 Angstroms 2% 22%
400-500 Angstroms 13% 29%
300-400 Angstroms 19% 18%
200-300 Angstroms 44% 14
<200 Angstroms 17% 17%
Total Pore Volume .26 cc/g .39 cc/g
It will also be noted that the halloysite with
dispersed rods has a substantially greater total pore
volume than the natural halloysite.
It is believed that the pores in the range of
200 Angstroms to about 700 Angstroms impart especially
2 good deasphalting properties to the catalyst support. One
explanation is that demetalation and desulfurization
reactions tend to be fast, therefore, pores significantly
larger than the molecules tend to allow rapid diffusion
into and out of the pores. Large pores are preferable in
demetalation catalysts since the metals removed from the
feedstocks tend to deposit on the surface of the catalyst
support, thereby rapidly plugging the mouths of the
smaller pores. Since there is no substantial amount of
pore volume in pores greater than 1000 Angstroms, there is
less problem with mechanically weak catalyst bodies and
attendant attrition.
The catalyst support and catalyst of this inven-
tion are versatile and can be u~ed for conversion of a
variety of hydrocarbonaceous feeds. This catalyst is
especially useful in hydroprocessing of heavy fractions
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01 _9_
which contain more than one percent by weight asphal-
tenes. Asphaltenes are defined herein to mean any hydro-
05 carbon fraction that is insoluble in n-heptane whether or
not it is soluble in benzene. Any feedstock containing
asphaltenes can be treated by use of this catalyst whether
or not the asphaltenes have been previously separated from
the remainder of the feedstock.
10The feedstocks with more than about 10 percent
asphaltenes are especially suitable for upgrading by use
of the present invention. Suitable feedstocks include
those oils that have an API gravity below about 25 or a
Conradson carbon residue of at least 7 percent. Particu-
larly suitable are those feedstocks that boil at greaterthan 550C. Suitable feedstocks include: crude petro-
leum, vacuum and atmospherlc residua from petroleum, coal-
liquids, shale oil, topped crudes and the like.
The present invention is especially suitable for
any of the numerous hydroconversion processes that use
molecular hydrogen. The generic conditions are exposing
the feedstock to hydrogen at a partial pressure ranging
from 0 to 200 atmospheres at between 200C and 540C, and
hydrogen to oil feed ratio of from zero to 9,000 standard
cubic liters per liter of oil and an hourly liquid space
velocity from about 0.1 to about 25 reciprocal hours.
Among the specific uses for which this catalyst is suit-
able are hydrocracking, hydrodesulfurization, hydrode-
nitrification, hydrodemetalation, and hydroconversion of
asphaltenes. The present catalyst is especially suitable
for hydrodemetalation and hydrocracking of asphaltenes.
The following examples are for illustrative
purposes only and should not be considered to be limiting.
Example I
35This example illustrates the preparation of a
catalyst support containing only halloysite without a
binder oxide or catalytic metals.
Naturally occurring halloysite from Dragon Iron
Mine, Utah, #13 powder is placed in a blender with enough
water to make a slurry of about 20 weight percent solid
01 --10-
content. The slurry is vigorously agitated in a Waring
blender until it reaches a constant thickness. After
05 removal from the blender, the clay containing slurry is
dried and calcined and shaped into catalytic bodies.
Example II
-
This example illustrates preparation of a
catalyst support containing halloysite and a binder
oxide. Dragon Halloysite ~13 powder is placed in a
blender. Enough 5 percent alumina by weight alumina
hydrogel is added to form a mixture that is 5 percent by
dry weight alumina. The alumina hydrogel is prepared
conventionally, as by peptizing a commercially available
alumina by a vigorous agitation with a peptizing agent
such as nitric acid or formic acid, or by precipitation of
the hydrogel from an aluminum nitrate solution with a base
such as ammonium hydroxide. Enough water is then added to
make a slurry that is no more than about 20 percent solid
content. The mixture is then vigorously agitated in a
Waring blender until the ~lurry no longer visibly
thickens. Once the halloysite rods are adequately disper-
sed, the slurry will not get any thicker. Normally this
takes about 10 minutes of agitation. Excess water is
evaporated from the slurry to form a plastic, workable
mass. The mixture is heated to 500C for three hours and
the calcined ~ass is broken up into catalyst particles.
Example III
A mixture of 50 9 of halloysite #13 from the
Dragon Iron Mine, Utah, 10 9 of attapulgite from Gadsden
City, Florida, and 25 g of alumina sol (20 percent Catapal*
alumina by weight) in 500 ml of water was agitated in a
Waring blender for 10 minutes. At this point the slurry
mixture had stopped visibly thickening. The slurry was
slowly evaporated dry at 110C to a thick paste which
could be easily extruded. The paste was extruded, and
dried and calcined at 500C.
* Trade mark
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Example IV
This example illustrates the deasphaltening
05 properties of a catalyst support made from dispersed rods
of halloysite.
A calcined catalyst support prepared by the
general method illustrated in Example I was impregnated by
a solution of phosphomolybdic acid and cobalt nitrate.
The impregnated catalyst contained 2 percent by weight of
cobalt and 6 percent by weight of molybdenum. The support
was employed for hydrodemetalizing a feedstock comprising
Arabian Atmospheric Residue in a microreactor. The
temperature was 382C, the pressure of hydrogen was 112
atmospheres, the hydrogen flow was 90 standard liters per
liter of feed and the liquid hourly space velocity was
0.86 reciprocal hours. The concentration of impurities in
the feedstock was reduced after hydrogen processing the
feedstock in the presence of the catalyst. Table II shows
the concentrations of the impurities in the feedstock
before and after hydrodemetalation.
TABLE II
V,ppm N,ppm % S% Asphaltene
Feed 83 22 4.4 7.2
Product 57 18 3.9 5.3
Table III shows the concentrations of impurities
in the asphaltene fraction of the feedstocks when the
heptane insoluble asphaltenes are separated and analyzed
separately
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01 -12--
TABLE III
05 V,ppm N,ppm % S
Asphaltenes From Feed 1030 300 10.5
Asphaltenes From
10Product 760 250 8 . 8
It will be appreciated that the asphaltene left
behind was cleaner than the asphaltene in the initial
feedstock.
Analysis of the catalyst particles revealed that
the metals deposited on the catalyst support tended to be
evenly distributed throughout the particles, rather than
on the surface only.
Example V
A series of catalysts were made according to the
general method of Example II except that varying amounts
of alumina were used in each preparation. The catalysts
were then placed in toluene solutions of asphaltenes and
the absorbance at 550 nm is monitored with respect to time
according to the method of Saint-Just (Ind. Eng. Chem.
Prod. R Div . 1980, 19, 71). 550 nm is chosen because
the absorbance of this wavelength of light has been corre-
lated to the concentration of vanadium, which in turn has
been correlated to the concentration of asphaltenes.
Table IV shows the absorbance of light at 550 nm
at varying time intervals for various halloysite catalysts
- that have varying amounts of alumina. As the catalyst
adsorbs asphaltenes, the solution becomes progressively
more clear, therefore, absorbing less light. Therefore,
the better catalyst compositions for deasphaltening action
will have lower final light absorbances.
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01 -13-
TABLE IV
05 Time (Minutes)
0 5 10 15 20 30
Halloysite with 1.0 0.280.14 0.0~ 0.06 0.04
0~ alumina
Halloysite with 1.0 0.220.01 0.05 0.04 0.03
5% alumina
Halloysite with 1.0 0.670.56 0.49 0.43 0.36
10% alumina
Halloysite with 1.0 1.0 1.0 1.0 1.0 1.0
25% alumina
Halloyqite with
5% alumina
~extruded) 1.0 0.92 0.850.82 0.79 0.73
It can be seen that the best asphaltene absorb-
ance is for the catalyst composition with 0-5 percent
alumina content, and asphaltenes are absorbed progres-
sively more poorly for the catalyst supports with higher
amounts of alumina. The extruded halloysite shows
decreased light absorbance with time, indicating that
asphaltene absorption onto the catalyst support is taking
place, but it is considerably inferior to the 5 percent
alumina catalyst that has been shaped by alternate
means. This is apparently due to a skin effect on the
extruded catalyst body that tends to realign the dispersed
rods during extrusion. The results of this absorbance
test can be roughly correlated to the pore size
distribution of the catalyst support, which should be
large enough to adsorb molecules the size of asphaltene
molecules. It will also be noted that there is no
decrease in light adsorbance in the 25 percent alumina
catalyst. It is thought that the pore sizes are too small
to allow the catalyst body to preferentially adsorb
asphaltenes. The light absorbance characteristics of this
series of dispersed rod catalysts indicate that dispersed
01 -14-
rods of halloysite can be superior catalyst supports for
hydroprocessing if the catalyst support contains no more
05 than about 15 percent binder oxide.
Example VI
The catalyst of Example III is tested for
absorbance. The absorbance of 550 nanometers (nm) of a
solution of asphaltenes dissolved in toluene is followed
with time according to the method of Saint-Just (Ind. Eng.
Chem. Prod. Res. Div., 1980, _ , '71). The wave length of
light chosen has been correlated to concentration of
vanadium in solution, which has in turn been correlated to
asphaltene concentration. Various catalysts are added. A
reduction in the absorbance means that the catalyst
preferentially adsorbs asphaltene materials from the
toluene solution. The results are tabulated in Table V.
It can be appreciated that the extruded halloysite/
attapulgite mixture adsorbs asphaltenes much better than
the extruded halloysite. It has been shown that good
demetalation catalysts will always show a marked decrease
in the absorbance of the toluene solution when tested in
this manner.
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