U.S. patent application number 12/878836 was filed with the patent office on 2010-12-30 for highly stable heavy hydrocarbon hydrodesulfurization catalyst and methods of making and use thereof.
Invention is credited to Opinder Kishan BHAN.
Application Number | 20100326890 12/878836 |
Document ID | / |
Family ID | 38961881 |
Filed Date | 2010-12-30 |
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United States Patent
Application |
20100326890 |
Kind Code |
A1 |
BHAN; Opinder Kishan |
December 30, 2010 |
HIGHLY STABLE HEAVY HYDROCARBON HYDRODESULFURIZATION CATALYST AND
METHODS OF MAKING AND USE THEREOF
Abstract
Described is a catalyst useful in the hydroprocessing of a heavy
hydrocarbon feedstock wherein the catalyst comprises a calcined
mixture made by calcining a formed particle of a mixture comprising
molybdenum trioxide, a nickel compound, and an inorganic oxide
material. The catalyst may be made by mixing an inorganic oxide
material, molybdenum trioxide, and a nickel compound to form a
mixture that is formed into a particle and calcined to provide a
calcined mixture. The process involves the hydrodesulfurization and
hydroconversion of a heavy hydrocarbon feedstock which process may
include the conversion of a portion of the pitch content of the
heavy hydrocarbon feedstock and the yielding of a treated product
having an enhanced stability as reflected by its P-value.
Inventors: |
BHAN; Opinder Kishan; (Katy,
TX) |
Correspondence
Address: |
SHELL OIL COMPANY
P O BOX 2463
HOUSTON
TX
772522463
US
|
Family ID: |
38961881 |
Appl. No.: |
12/878836 |
Filed: |
September 9, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11832461 |
Aug 1, 2007 |
7820036 |
|
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12878836 |
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60821341 |
Aug 3, 2006 |
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Current U.S.
Class: |
208/216PP ;
208/216R; 502/255; 502/314 |
Current CPC
Class: |
B01J 37/04 20130101;
B01J 37/08 20130101; B01J 35/002 20130101; B01J 35/1061 20130101;
B01J 37/0009 20130101; B01J 35/1042 20130101; C10G 45/08 20130101;
B01J 23/883 20130101; B01J 35/1019 20130101; B01J 35/108 20130101;
C10G 45/12 20130101 |
Class at
Publication: |
208/216PP ;
502/255; 502/314; 208/216.R |
International
Class: |
C10G 45/08 20060101
C10G045/08; B01J 21/08 20060101 B01J021/08; B01J 23/883 20060101
B01J023/883 |
Claims
1. A method, comprising: preparing a calcined mixture by calcining
a mixture, wherein said mixture is prepared by co-mulling
particulate molybdenum trioxide, comprising molybdenum trioxide
particles of a particle size of greater than 0.2 .mu.m and less
than 500 .mu.m; inorganic refractory oxide selected from the group
consisting of silica, alumina, and silica-alumina; and a nickel
compound to provide said mixture; wherein said mixture comprises
less than 2 weight percent, based on the total weight of said
mixture, of a molybdenum compound other than molybdenum trioxide,
an amount of molybdenum trioxide so as to provide a molybdenum
content in said calcined mixture in the range upwardly to 12 weight
percent, as metal, with the weight percent being based on the total
weight of said calcined mixture, an amount of nickel compound so as
to provide a nickel content in said calcined mixture in the range
upwardly to 4 weight percent, as metal, with the weight percent
being based on the total weight of said calcined mixture, and an
amount of inorganic refractory oxide so as to provide from 50 to 95
weight percent inorganic refractory oxide in said calcined mixture,
with the weight percent being based on the total weight of said
calcined mixture.
2. A method as recited in claim 1, further comprising: forming said
mixture into shaped or formed particles prior to said calcining of
said mixture.
3. A method as recited in claim 2, wherein said calcining step is
conducted at a calcination temperature in the range of from
450.degree. C. to 760.degree. C.
4. A method as recited in claim 3, wherein said particle size is
less than 150 .mu.m; wherein said molybdenum content in said
calcined mixture is in the range of from 4 to 11 wt. %; wherein
said nickel content in said calcined mixture is in the range of
from 0.5 to 3.5 wt. %; and wherein said amount of inorganic
refractory oxide is in the range of from 60 to 92 weight percent of
said calcined mixture.
5. A method as recited in claim 4, wherein said calcined mixture
has a low macroporosity such that less than 4.5 percent of the
total pore volume is contained within its macropores; wherein said
calcined mixture has a mean pore diameter in the range of from 85
angstroms to 100 angstroms; wherein said calcined mixture has a
surface area that exceeds 230 m.sup.2/g; and wherein less than 1
percent of the total pore volume contained within the macropores of
said calcined mixture a diameter greater than 1000 angstroms.
6. A method as recited in claim 5, wherein said mixture consists
essentially of molybdenum trioxide, said nickel compound, and said
inorganic refractory oxide.
7. A method as recited in claim 6, wherein said particle size is
less than 150 .mu.m; wherein said molybdenum content in said
calcined mixture is in the range of from 5 to 10 wt. %; wherein
said nickel content in said calcined mixture is in the range of
from 1 to 3 wt. %; wherein said amount of inorganic refractory
oxide present in said calcined mixture is in the range of from 70
to 89 weight percent; wherein said low macroporosity is such that
less than 4 percent of the total pore volume is contained within
the macropores of said calcined mixture; wherein said mean pore
diameter of said calcined mixture is in the range of from 86
angstroms to 98 angstroms; wherein said surface area exceeds 240
m.sup.2/g; and wherein less than 0.9 percent of the total pore
volume of said calcined mixture is contained within its macropores
having a diameter greater than 1000 angstroms.
8. A composition, comprising: a mixture that has been calcined to
provide a calcined mixture, and wherein said mixture consists
essentially of molybdenum trioxide particles of a particle size of
greater than 0.2 .mu.m and less than 500 .mu.m; inorganic
refractory oxide selected from the group consisting of silica,
alumina, and silica-alumina; and a nickel compound, wherein said
mixture comprises less than 2 weight percent, based on the total
weight of said mixture, of a molybdenum compound other than
molybdenum trioxide, an amount of molybdenum trioxide so as to
provide a molybdenum content in said calcined mixture in the range
upwardly to 12 weight percent, as metal, with the weight percent
being based on the total weight of said calcined mixture, an amount
of nickel compound so as to provide a nickel content in said
calcined mixture in the range upwardly to 4 weight percent, as
metal, with the weight percent being based on the total weight of
said calcined mixture, and an amount of inorganic refractory oxide
so as to provide from 50 to 95 weight percent inorganic refractory
oxide in said calcined mixture, with the weight percent being based
on the total weight of said calcined mixture.
9. A composition as recited in claim 8, wherein said particle size
is less than 150 .mu.m; wherein said molybdenum content in said
calcined mixture is in the range of from 4 to 11 wt. %; wherein
said nickel content in said calcined mixture is in the range of
from 0.5 to 3.5 wt. %; and wherein said amount of inorganic
refractory oxide is in the range of from 60 to 92 weight percent of
said calcined mixture.
10. A composition as recited in claim 9, wherein said calcined
mixture has a low macroporosity such that less than 4.5 percent of
the total pore volume is contained within its macropores; wherein
said calcined mixture has a mean pore diameter in the range of from
85 angstroms to 100 angstroms; wherein said calcined mixture has a
surface area that exceeds 230 m.sup.2/g; and wherein less than 1
percent of the total pore volume contained within the macropores of
said calcined mixture a diameter greater than 1000 angstroms.
11. A composition as recited in claim 10, wherein said mixture
consists essentially of molybdenum trioxide, said nickel compound,
and said inorganic refractory oxide.
12. A composition as recited in claim 11, wherein said particle
size is less than 150 .mu.m; wherein said molybdenum content in
said calcined mixture is in the range of from 5 to 10 wt. %;
wherein said nickel content in said calcined mixture is in the
range of from 1 to 3 wt. %; wherein said amount of inorganic
refractory oxide present in said calcined mixture is in the range
of from 70 to 89 weight percent; wherein said low macroporosity is
such that less than 4 percent of the total pore volume is contained
within the macropores of said calcined mixture; wherein said mean
pore diameter of said calcined mixture is in the range of from 86
angstroms to 98 angstroms; wherein said surface area exceeds 240
m.sup.2/g; and wherein less than 0.9 percent of the total pore
volume of said calcined mixture is contained within its macropores
having a diameter greater than 1000 angstroms.
13. A process, comprising: contacting a heavy hydrocarbon feedstock
having a T(5) exceeding 300.degree. C., from 10 volume percent to
90 volume percent pitch, a sulfur content greater than 1 weight
percent, and an MCR value exceeding 6% with a catalyst composition
comprising either a composition as recited in any one of claims 8
through 12 or a calcined mixture prepared by any of the methods of
claims 1 through 7 under hydroprocessing conditions so as to
provide a treated hydrocarbon product having a reduced sulfur
content of less than 1 weight percent, a conversion of greater than
20 volume percent of the pitch in said heavy hydrocarbon feedstock,
and a reduced MCR value of less than 6%.
14. A process as recited in claim 13, wherein said heavy
hydrocarbon feedstock further characterized as having a P-value of
less than 1 and said treated hydrocarbon product has a P-value
exceeding 1.25.
15. A process as recited in claim 13, wherein said hydroprocessing
conditions include a reaction pressure in the range of from 2298
kPa to 20,684 kPa, a reaction temperature in the range of from
340.degree. C. to 480.degree. C., and a liquid hourly space
velocity (LHSV) in the range of from 0.01 hr.sup.-1 to 3 hr.sup.-1.
Description
[0001] This is a divisional application of U.S. application Ser.
No. 11/832,461, filed Aug. 1, 2007, which claims the benefit of
U.S. Provisional Application Ser. No. 60/821,341, filed Aug. 3,
2006.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a catalyst, a method of making a
catalyst and a process for making a hydrocarbon product having a
low sulfur concentration. The invention further relates to a highly
stable catalyst that is useful in the hydrodesulfurization of a
heavy hydrocarbon feedstock, a method of making a highly stable
catalyst for use in the hydrodesulfurization of a heavy hydrocarbon
feedstock, and a process for the hydrodesulfurization of a heavy
hydrocarbon product.
[0003] One process that is recognized by those skilled in the art
of hydrocarbon hydroprocessing is the hydroconversion of heavy
hydrocarbon feedstocks that contain hydrocarbons boiling above
about 538.degree. C. (1000.degree. F.) so as to convert a portion
of the heavy hydrocarbons into lighter hydrocarbons. It may also be
desirable to simultaneously provide for the reduction of the sulfur
content of such heavy hydrocarbon feedstocks. Many of the
conventional catalysts used to provide for the hydroconversion and
desulfurization of heavy hydrocarbon feedstocks contain a Group VIB
metal component, such as molybdenum, and a Group VIII metal
component, such as cobalt or nickel, supported on a refractory
oxide support.
[0004] U.S. Pat. No. 5,827,421 (Sherwood, Jr) discloses a process
for the hydroconversion and desulfurization of a heavy hydrocarbon
feedstock using an alumina supported catalyst containing Group VIII
and Group VIB metals and having specifically defined surface and
pore characteristics. In its background section, this patent
provides an extensive review and discussion of the prior art and
the therein described catalysts used in the hydroconversion of
heavy hydrocarbon feedstocks such as petroleum resid and other
heavy hydrocarbons. This patent does not, however, provide any
detail on the use of molybdenum trioxide as a necessary source of
the molybdenum component of a hydroprocessing catalyst composition
that is made by a method that includes the co-mulling of the
molybdenum trioxide with an inorganic oxide material and a nickel
compound.
[0005] U.S. Pat. No. 5,686,375 (Iyer et al.) mentions
hydroprocessing catalysts that contain underbedded Group VIII metal
components with the preferred catalyst comprising underbedded
nickel and an overlayer of molybdenum. The patent states that many
nickel and molybdenum compounds are useful for impregnation or
comulling including precursors of molybdenum trioxide, but it does
not specifically mention the comulling of molybdenum trioxide with
the porous refractory support material in the preparation of its
catalyst support that has an underbedded molybdenum component. The
patent does, however, mention the incorporation of molybdenum onto
the support that contains underbedded nickel by comulling instead
of by impregnation. But, there is no teaching in the '375 patent of
the preparation of a heavy hydrocarbon hydroconversion catalyst by
the comulling of an inorganic support material with both molybdenum
trioxide and a nickel compound followed by the resulting mixture
being calcined to thereby form a catalyst material.
[0006] U.S. Pat. No. 6,030,915 (de Boer) discloses a
hydroprocessing catalyst that uses regenerated spent
hydroprocessing catalyst fines in the manufacture of a
hydroprocessing catalyst. The patent further indicates that
additional hydrogenation metals may be added to the catalyst
composition by impregnation using an impregnation solution
comprising water soluble salts of the hydrogenation metals to be
incorporated into the catalyst composition. Also, an alternative
method of incorporating the extra metal into the catalyst
composition is indicated as including the mixing of either solid
state or dissolved metal components with the mixture of regenerated
spent hydroprocessing catalyst fines, binder, and, optionally,
additive. The solid state metal may include solid molybdenum oxide.
Additives are not indicated as being a catalytic metal compound. In
the preparation of its catalyst, the '915 patent requires the
regenerated spent hydroprocessing catalyst fines to be mixed with
at least one additive, which may include a binder, such as alumina,
silica, silica-alumina, titania and clays.
BRIEF SUMMARY OF THE INVENTION
[0007] It is desirable to have a catalyst that has a low production
cost and which is useful in the hydrodesulfurization of a heavy
hydrocarbon feedstock, such as a crude oil residue, while providing
for a conversion of at least a portion of the heavy end of the
heavy hydrocarbon feedstock to lighter hydrocarbons. It is further
desirable for the hydrodesulfurized heavy hydrocarbon conversion
product resulting from the use of the catalyst to exhibit highly
stable properties as reflected by its P-value. It is also desirable
for the hydroconversion catalyst to exhibit a low rate of
deactivation at the higher temperatures that are typically required
for providing for the conversion of the heavy end of a heavy
hydrocarbon feedstock.
[0008] Thus, accordingly, a highly stable heavy hydrocarbon
hydrodesulfurization catalyst is provided that comprises a calcined
mixture made by calcining a formed particle of a mixture comprising
molybdenum trioxide, a nickel compound, and an inorganic oxide
material. This highly stable heavy hydrocarbon hydrodesulfurization
catalyst may be made by the method comprising: co-mulling an
inorganic oxide material, molybdenum trioxide, and a nickel
compound to form a mixture; forming said mixture into a particle;
and calcining said particle to provide a calcined mixture. The
highly stable heavy hydrocarbon hydrodesulfurization catalyst
further may be used in a process for the desulfurization of a heavy
hydrocarbon feedstock, wherein said process comprises: contacting,
under suitable heavy hydrocarbon desulfurization conditions, a
heavy hydrocarbon feedstock with a heavy hydrocarbon
hydrodesulfurization catalyst comprising a calcined mixture made by
calcining a formed particle of a mixture comprising molybdenum
trioxide, a nickel compound, and an inorganic oxide material; and
yielding a desulfurized product.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 presents plots of the P-value of the product yielded
from the hydroprocessing of heavy hydrocarbon feedstock when using
the inventive catalyst as compared to a comparison catalyst as a
function of pitch conversion. As may be seen from the two plots,
the inventive catalyst provides for a product having a higher
P-value than that provided by the comparison catalyst and, thus, a
more stable product.
[0010] FIG. 2 presents comparison plots of the relative values for
the calculated Weight Average Bed Temperature (WABT) as a function
of time for an 88% hydrodesulfurization of a heavy feedstock using
the inventive catalyst as compared to a comparison catalyst. The
slope of the plots provide an indication of the stability of the
catalyst activity, and the relative positions of the two plots
reflects the relative catalytic activity of the catalysts.
DETAILED DESCRIPTION OF THE INVENTION
[0011] A novel catalyst composition has been discovered that is
especially useful in the hydrodesulfurization and hydroconversion
of heavy hydrocarbon streams that contain sulfur and heavy
hydrocarbons having a boiling temperature greater than 538.degree.
C. (1000.degree. F.). This catalyst composition exhibits
exceptional stability in its desulfurization activity even though
it is used at higher process temperature conditions than those
typically used for hydrodesulfurization in order to provide for
high conversion of the heavy hydrocarbons contained in the heavy
hydrocarbon stream that is to be processed or treated. Also, the
catalyst composition provides for a hydroconverted and desulfurized
product that exhibits high stability in the sense that it has a low
flocculation tendency as compared to hydroconverted products
resulting from the use of alternative catalysts. Aside from the
numerous catalytic and process advantages that the novel catalyst
provides, it also has a low cost to produce due to the novel method
of making the catalyst composition.
[0012] The inventive catalyst composition comprises a calcined
mixture that is made by calcining a formed particle of a mixture
comprising molybdenum trioxide, a nickel compound, and an inorganic
oxide material. It is an essential aspect of the invention for at
least a major portion of the molybdenum component of the inventive
catalyst to be supplied by molybdenum trioxide as opposed to
precursors of molybdenum trioxide such as certain of the salts of
molybdenum, for example, ammonium dimolybdate and ammonium
heptamolybdate. And, indeed, it is an important aspect of the
invention for the mixture from which the particle is formed is to
be made using molybdenum trioxide. It is preferred for the
molybdenum trioxide used in the formation of the mixture to be in
the form of a finely defined powder, which may be in a liquid
suspension or slurry. Therefore, the mixture that is formed into a
particle and thereafter calcined can comprise a substantial absence
of a molybdenum compound that is in a form other than as molybdenum
trioxide, such as, for example, a molybdenum salt compound.
[0013] What is meant herein when referring to the substantial
absence of a molybdenum compound in a form other than as molybdenum
trioxide is that the mixture that is shaped or formed into a formed
particle and thereafter calcined under suitable calcination
conditions, as more fully described elsewhere herein, contains less
than a small or less than a negligible amount of a molybdenum
compound other than molybdenum trioxide, such as, for example, a
molybdenum salt compound or an inorganic molybdenum compound.
Examples of molybdenum compounds other than molybdenum trioxide
include ammonium molybdate, ammonium dimolybdate, ammonium
heptamolybdate, molybdenum acetate, molybdenum bromide, molybdenum
chloride, molybdenum sulfide, and molybdenum carbide. It is, thus,
desirable for the mixture to contain less than 2 weight percent,
based on the total weight of the mixture, of a molybdenum compound
other than molybdenum trioxide. It is preferred for the mixture to
contain less than 1 weight percent of a molybdenum compound other
than molybdenum trioxide, and, most preferred, less than 0.5 weight
percent.
[0014] In another embodiment of the invention, the mixture may
consist essentially of molybdenum trioxide, a nickel compound, and
an inorganic oxide material. As the phrase "consist essentially
of", or similar phraseology, is used herein in defining the
elements or components that make up the mixture, what is meant is
that a material amount of any molybdenum compound other than
molybdenum trioxide is excluded from the mixture. This phrase,
however, is not intended to mean that excluded from the recited
components of the mixture are material amounts of other compounds
such as promoter components including phosphorous compounds. A
material amount of a molybdenum compound other than molybdenum
trioxide is an amount of such compound contained in the mixture
that provides for a material effect upon the catalytic performance
properties of the final catalyst. These catalyst performance
properties are discussed in detail elsewhere herein.
[0015] The amount of molybdenum trioxide that is contained in the
mixture should be such as to provide for the final calcined mixture
having a molybdenum content in the range upwardly to 12 weight
percent, as metal, (18 wt. % based on MoO.sub.3), with the weight
percent being based on the total weight of the calcined mixture.
However, it is desirable for the amount of molybdenum trioxide that
is contained in the mixture to be such as to provide for the final
calcined mixture having a molybdenum content in the range of from 4
to 11 wt. %, as metal (6 to 16.5 wt. %, as oxide), but, preferably,
from 5 to 10 wt. % (7.5 to 15 wt. %, as oxide), and, most
preferably, from 6 to 9 wt. % (9 to 13.5 wt. %, as oxide).
[0016] In addition to the molybdenum trioxide component, the
mixture further contains a nickel compound. The source of the
nickel component of the mixture is not as critical to the
manufacture of the inventive catalyst as is the source of the
molybdenum component, and, thus, the nickel component may be
selected from any suitable nickel compound that is capable of being
mixed with the other components of the mixture and to be shaped
into a particle that is to be calcined to form the final calcined
mixture. The nickel compounds may include, for example, the nickel
hydroxides, nickel nitrates, nickel acetates, and nickel
oxides.
[0017] The amount of nickel compound that is contained in the
mixture should be such as to provide for the final calcined mixture
having a nickel content in the range upwardly to 4 weight percent,
as metal, (5.1 wt. % based on NiO), with the weight percent being
based on the total weight of the calcined mixture. However, it is
desirable for the amount of the nickel compound that is contained
in the mixture to be such as to provide for the final calcined
mixture having nickel content in the range of from 0.5 to 3.5 wt.
%, as metal (0.64 to 4.45 wt. %, as oxide), but, preferably, from 1
to 3 wt. % (1.27 to 3.82 wt. %, as oxide), and, most preferably,
from 1.5 to 2.5 wt. % (1.91 to 3.18 wt. %, as oxide).
[0018] In addition to the molybdenum trioxide component and the
nickel compound, the mixture further includes an inorganic oxide
material. Any suitable porous inorganic refractory oxide that will
provide the surface structure properties required for the inventive
catalyst may be used as the inorganic oxide material component of
the mixture. Examples of possible suitable types of porous
inorganic refractory oxides include silica, alumina, and
silica-alumina. Preferred is either alumina or silica-alumina.
[0019] The amount of inorganic oxide material that is contained in
the mixture is such as to provide an amount in the range of from 50
to 95 weight percent inorganic oxide material in the final calcined
mixture with the weight percent being based on the total weight of
the calcined mixture. Preferably, the amount of inorganic oxide
material in the calcined mixture is in the range of from 60 to 92
weight percent, and, most preferably, from 70 to 89 weight
percent.
[0020] In addition to the requirement that the source of the
molybdenum component of the inventive catalyst is to be
predominantly provided by molybdenum trioxide, the surface
characteristics of the inventive catalyst can also be important to
its performance in the hydroconversion and desulfurization of a
heavy hydrocarbon feed stream containing a concentration of sulfur.
It is important for the inventive catalyst to have a mean pore
diameter that is within a specific, narrow range and to have a low
macroporosity as hereafter described. In order to provide for the
desired catalytic properties, the mean pore diameter of the
inventive catalyst is, generally, in the range of from 85 angstroms
(.ANG.) to 100 .ANG.. Preferably, the mean pore diameter is in the
range of from 86 to 98 angstroms, and, most preferably, from 87 to
97 angstroms.
[0021] The inventive catalyst should, in addition to having a mean
pore diameter that is within the specific and narrow range as
discussed above, also have a low macroporosity where a small
percentage of the total pore volume of the catalyst is contained
within the macropores of the inventive catalyst. The term macropore
is defined as a catalyst pore of a catalyst composition having a
diameter greater than 350 angstroms. It is preferred for the
inventive catalyst to have a low macroporosity such that less than
4.5 percent of the total pore volume is contained within its
macropores, but, more preferred, is that less than 4 percent of the
total pore volume is contained in its macropores, and, most
preferred, less than 3.5 percent of the total pore volume is
contained in its macropores. Also, it is desirable for the pore
structure of the inventive catalyst to be such that less than 1
percent of the total pore volume to be contained within its
macropores having a diameter greater than 1000 angstroms, and it is
more desirable that less than 0.9 percent of the total pore volume
to be contained within the macropores having a diameter greater
than 1000 angstroms, and, most desirable, less than 0.8 percent of
the total pore volume to be contained within the macropores having
a diameter greater than 1000 angstroms
[0022] A further important property of the inventive catalyst is
for it to have a significantly high surface area. It is the
particular combination of a significantly high surface area in
combination with the narrow distribution of pore diameters and the
use of the molybdenum trioxide as the molybdenum source in the
manufacture of the inventive catalyst that contributes to many of
the important performance properties of the inventive catalyst. It
is desirable for the inventive catalyst to have a reasonably high
surface area that exceeds 230 m.sup.2/g. Preferably, the surface
area of the inventive catalyst exceeds 240 m.sup.2/g, and, most
preferably, it exceeds 250 m.sup.2/g.
[0023] It has been found that the inventive method provides for the
novel catalyst that, as earlier noted, exhibits particularly good
properties when it is used in the dual hydrodesulfurization and
hydroconversion of a heavy hydrocarbon stream that contains both a
concentration of sulfur and heavy hydrocarbons. While it is not
known with certainty, it is believed that many of the beneficial
catalytic properties of the inventive catalyst are associated with
the novel method of manufacturing the catalyst and, also, in the
use of molybdenum trioxide for the principal source of the
molybdenum component of the catalyst as opposed to the use of
alternative molybdenum sources in such manufacturing. It is
surmised that the reason for this is in some way associated with
molybdenum trioxide having acidic and other unique properties such
that when it is combined with the alumina it more effectively
incorporates and disperses itself within the alumina matrix. In
fact, an examination of certain scan electron micrographs of the
inventive catalyst that has been sulfided suggests that there is a
significantly lower degree of molybdenum disulfide (MoS.sub.2) slab
stacking with the stacks having reduced heights and lengths as
compared to alternative molybdenum-containing hydroprocessing
catalysts.
[0024] The inventive method for making the catalyst of the
invention includes the mixing of the appropriate starting materials
to form a mixture that is formed or agglomerated into particles
that are then calcined to thereby provide a calcined mixture. The
calcined mixture itself may be used as the highly stable dual
hydroconversion and hydrodesulfurization catalyst or it may be
activated prior to or during its use by any number of known methods
including treatment with hydrogen or with sulfur or sulfur
compounds, such as, elemental sulfur, hydrogen sulfide or an
organic sulfur compound.
[0025] The first step of the inventive method includes combining
the starting materials of the catalyst to form a mixture. The
essential starting materials in the preparation of the mixture
include molybdenum trioxide that is preferably in the form of
finely divided particles that may be as a dry powder or as
particles in a suspension or slurry, and an inorganic oxide
material, such as, inorganic oxide material selected from the group
consisting of alumina, silica and alumina-silica. Also, a nickel
component may further be combined with the molybdenum trioxide and
inorganic oxide material in the formation of the mixture. The
nickel component may be selected from any suitable source of nickel
including nickel salt compounds, both dry or dissolved in solution,
or any other nickel compound including those mentioned above.
[0026] The formation of the mixture may be done by any method or
means known to those skilled in the art, including, but not limited
to, the use of such suitable types of solids-mixing machines as
tumblers, stationary shells or troughs, muller mixers, which are
either batch type or continuous type, and impact mixers, and the
use of such suitable types of either batch-wise or continuous
mixers for mixing solids and liquids or for the formation of
paste-like mixtures that are extrudable. Suitable types of batch
mixers include, but are not limited to, change-can mixers,
stationary-tank mixers, double-arm kneading mixers that are
equipped with any suitable type of mixing blade. Suitable types of
continuous mixers include, but are not limited to, single or double
screw extruders, trough-and-screw mixers and pug mills.
[0027] The mixing of starting materials of the catalyst may be
conducted during any suitable time period necessary to properly
homogenize the mixture. Generally, the blending time may be in the
range of upwardly to 2 or more than 3 hours. Typically, the
blending time is in the range of from 0.1 hours to 3 hours.
[0028] The term "co-mulling" is used broadly in this specification
to mean that at least the recited starting materials are mixed
together to form a mixture of the individual components of the
mixture that is preferably a substantially uniform or homogeneous
mixture of the individual components of such mixture. This term is
intended to be broad enough in scope to include the mixing of the
starting materials so as to yield a paste that exhibits properties
making it capable of being extruded or formed into extrudate
particles by any of the known extrusion methods. But, also, the
term is intended to encompass the mixing of the starting materials
so as to yield a mixture that is preferably substantially
homogeneous and capable of being agglomerated into formed
particles, such as, spheroids, pills or tablets, cylinders,
irregular extrusions or merely loosely bound aggregates or
clusters, by any of the methods known to those skilled in the art,
including, but not limited to, molding, tableting, pressing,
pelletizing, extruding, and tumbling.
[0029] As already noted, it is an important aspect of the inventive
method for at least a major portion of the molybdenum source of the
catalyst to be predominantly molybdenum trioxide. In the mixing or
co-mulling of the starting materials of the catalyst, it is
preferred for the molybdenum trioxide to be in a finely divided
state either as a finely powdered solid or as fine particles in a
suspension or slurry. It is best for the particle sizes of the
particulate molybdenum trioxide used in the manufacture of the
catalyst to have a maximum dimension of less than 0.5 mm (500
microns, .mu.m), preferably, a maximum dimension of less than 0.15
mm (150 .mu.m), more preferably, less than 0.1 mm (100 .mu.m), and,
most preferably, less than 0.075 mm (75 .mu.m).
[0030] While it is not known with certainty, it is believed that it
is advantageous to the invention for the molybdenum trioxide that
is used in the manufacture of the inventive catalyst to be in the
form of as small particles as is practically possible; so,
therefore, it is not desired to have a lower limit on the size of
the molybdenum trioxide particles used in the manufacture of the
catalyst. However, it is understood that the particle size of the
molybdenum trioxide used in the manufacture of the catalyst will
generally have a lower limit to its size of greater than 0.2
microns. Thus, the particle size of the molybdenum trioxide used in
the formation of the mixture in the manufacture of the inventive
catalyst is preferably in the range of from 0.2 to 150 .mu.m, more
preferably, from 0.3 to 100 .mu.m, and, most preferably, from 0.5
to 75 .mu.m. Typically, the size distribution of the molybdenum
trioxide particles, whether in a dry powder or a suspension or
otherwise, is such that at least 50 percent of the particles have a
maximum dimension in the range of from 2 to 15 .mu.m.
[0031] Once the starting materials of the catalyst are properly
mixed and formed into the shaped or formed particles, a drying step
may advantageously be used for removing certain quantities of water
or volatiles that are included within the mixture or formed
particles. The drying of the formed particles may be conducted at
any suitable temperature for removing excess water or volatiles,
but, preferably, the drying temperature will be in the range of
from about 75.degree. C. to 250.degree. C. The time period for
drying the particles is any suitable period of time necessary to
provide for the desired amount of reduction in the volatile content
of the particles prior to the calcination step.
[0032] The dried or undried particles are calcined in the presence
of an oxygen-containing fluid, such as air, at a temperature that
is suitable for achieving a desired degree of calcination.
Generally, the calcination temperature is in the range of from
450.degree. C. (842.degree. F.) to 760.degree. C. (1400.degree.
F.). The temperature conditions at which the particles are calcined
can be important to the control of the pore structure of the final
calcined mixture. Due to the presence of the molybdenum trioxide in
the formed particles, the calcination temperature required to
provide for a calcined mixture having the required pore structure
is higher than typical temperatures required to calcine other
compositions containing inorganic oxide materials, especially those
that do not contain molybdenum trioxide. But, in any event, the
temperature at which the formed particles are calcined to provide
the finally calcined mixture is controlled so as to provide the
finally calcined mixture having the pore structure properties as
described in detail herein. The preferred calcination temperature
is in the range of from 510.degree. C. (950.degree. F.) to
730.degree. C. (1346.degree. F.), and, most preferably, from
540.degree. C. (1004.degree. F.) to 705.degree. C. (1301.degree.
F.).
[0033] The calcined mixture is particularly useful as a high
stability hydroprocessing catalyst for use in the hydroprocessing
of a heavy feedstock stream that has high pitch and sulfur
contents. Prior to its use, the calcined mixture may, but is not
required to, be sulfided or activated by any of the methods known
to those skilled in the art. Generally, in its use in the
hydroprocessing of a hydrocarbon feedstock, the calcined mixture is
contained within a reaction zone, such as that which is defined by
a reactor vessel, wherein a hydrocarbon feedstock is contacted with
the calcined mixture under suitable hydroprocessing reaction
conditions and from which a treated hydrocarbon product is
yielded.
[0034] The preferred hydrocarbon feedstock of the inventive process
is a heavy hydrocarbon feedstock. The heavy hydrocarbon feedstock
may be derived from any of the high boiling temperature petroleum
cuts such as atmospheric tower gas oils, atmospheric tower bottoms,
vacuum tower gas oils, and vacuum tower bottoms or resid. It is a
particularly useful aspect of the inventive process to provide for
the hydroprocessing of a heavy hydrocarbon feedstock that can be
generally defined as having a boiling temperature at its 5%
distillation point, i.e. T(5), that exceeds 300.degree. C.
(572.degree. F.) as determined by using the testing procedure set
forth in ASTM D-1160. The invention is more particularly directed
to the hydroprocessing of a heavy hydrocarbon feedstock having a
T(5) that exceeds 315.degree. C. (599.degree. F.) and, even, one
that exceeds 340.degree. C. (644.degree. F.).
[0035] The heavy hydrocarbon feedstock further may include heavier
hydrocarbons that have boiling temperatures above 538.degree. C.
(1000.degree. F.). These heavier hydrocarbons are referred to
herein as pitch, and, as already noted, it is recognized that one
of the special features of the inventive catalyst or process is
that it is particularly effective in the hydroconversion of the
pitch content of a heavy hydrocarbon feedstock. The heavy
hydrocarbon feedstock may include as little as 10 volume percent
pitch or as much as 90 volume percent pitch, but, generally, the
amount of pitch included in the heavy hydrocarbon feedstock is in
the range of from 20 to 80 volume percent. And, more typically, the
pitch content in the heavy hydrocarbon feedstock is in the range of
from 30 to 75 volume percent.
[0036] The heavy hydrocarbon feedstock further may include a
significantly high sulfur content. One of the special features of
the invention is that it provides for both the desulfurization of
the heavy hydrocarbon feedstock and the conversion of the pitch to
lighter hydrocarbons having lower boiling temperatures than those
of the pitch hydrocarbons. The sulfur content of the heavy
hydrocarbon feedstock is primarily in the form of organic
sulfur-containing compounds, which may include, for example,
mercaptans, substituted or unsubstituted thiophenes, heterocyclic
compounds, or any other type of sulfur-containing compound.
[0037] A feature of the invention is that it provides for the
desulfurization of the heavy feedstock that has a significantly
high sulfur content, such as a sulfur content greater than 1 weight
percent, so as to provide for a treated hydrocarbon product having
a reduced sulfur content, such as a sulfur content of less than 1
weight percent. When referring herein to the sulfur content of
either the heavy hydrocarbon feedstock or the treated hydrocarbon
product, the weight percents are determined by the use of testing
method ASTM D-4294. The inventive process is particularly useful in
the processing of a heavy hydrocarbon feedstock that has a sulfur
content exceeding 2 weight percent, and with such a heavy
hydrocarbon feedstock, the sulfur content may be in the range of
from 2 to 8 weight percent. The inventive catalyst and process is
especially useful in the processing of a heavy hydrocarbon
feedstock having an especially high sulfur content of exceeding 3
or even 4 weight percent and being in the range of from 3 to 7
weight percent or even from 4 to 6.5 weight percent.
[0038] The inventive process utilizes the inventive catalyst in the
hydroprocessing of the heavy hydrocarbon feedstock to provide for
the simultaneous desulfurization and conversion of pitch to yield
the treated hydrocarbon product having reduced sulfur and pitch
contents. In this process, the heavy hydrocarbon feedstock is
contacted with the inventive catalyst under suitable
hydrodesulfurization and hydroconversion process conditions and the
treated hydrocarbon product is yielded. The treated hydrocarbon
product should have a reduced sulfur content that is below that of
the heavy hydrocarbon feedstock, such as a sulfur content of less
than 1 weight percent. It is preferred for the reduced sulfur
content of the treated hydrocarbon product to be less than 0.8
weight percent, and, most preferably, less than 0.6 weight percent.
It is recognized that the inventive process, however, may have the
capability of effectively desulfurizing the heavy hydrocarbon
feedstock to provide the treated hydrocarbon product having a
reduced sulfur content of less than 0.5 and even less than 0.4
weight percent.
[0039] The inventive process may further provide for a conversion
of a portion of the pitch content of the heavy hydrocarbon
feedstock. When referring herein to the conversion of pitch or to
pitch conversion or other similar terminology, what is meant is
that a portion of the hydrocarbons contained in the heavy
hydrocarbon feedstock that has a boiling temperature exceeding
538.degree. C. (1000.degree. F.) is converted to hydrocarbons
having a boiling temperature less than 538.degree. C. (1000.degree.
F.). In a preferred embodiment of the inventive process, the pitch
conversion is greater than 20 volume percent of the pitch contained
in the heavy hydrocarbon feedstock, and, more preferably, the pitch
conversion exceeds 30 volume percent. Most preferably, the pitch
conversion exceeds 40 volume percent of the pitch contained in the
heavy hydrocarbon feedstock. A practical upper limit for the pitch
conversion is 90 volume percent, and, more typically, the upper
limit for the pitch conversion is 60 volume percent. Thus, the
pitch conversion, for example, may be in the range of from 20 to 90
volume percent, or from 30 to 60 volume percent, or from 40 to 60
volume percent.
[0040] At higher levels of pitch conversion the treated hydrocarbon
product quality tends to suffer. This is believed to be due to the
agglomeration of the asphaltene structures contained in the heavy
hydrocarbon feedstock being processed. This agglomeration can, at
extreme conditions, result in the separation of the solid fraction
from the treated hydrocarbon product and laying down or deposition
of the solids upon process equipment surfaces. In general, the
upper limit of pitch conversion is the point at which product
precipitation begins to appear. Various techniques have been used
in the petroleum process industry to predict the onset of such
precipitation, including proprietary testing methods and the
P-value test as it is more fully described elsewhere herein.
[0041] One of the advantages provided by the high pitch conversion
of the inventive process is that it results in yielding of the
treated hydrocarbon product having hydrocarbons having boiling
temperatures in the naphtha, distillate (diesel and kerosene), and
vacuum gas oil temperature ranges. These yielded products may be
pooled with product streams made by other refinery process units or
they may be further processed. For instance, the distillate
products of the inventive process may undergo further
hydroprocessing to yield such products as kerosene, aviation fuel
and diesel, and the vacuum gas oil product of the inventive process
may be used as feedstock to a refinery unit such as a fluid
catalytic cracking unit or a hydrocracking unit. Depending upon the
particular market conditions, the distillate fraction yielded from
the inventive process can be especially valuable, thus, making a
higher distillate yield, as opposed to higher yields of naphtha and
vacuum gas oil, highly desirable.
[0042] In addition to providing for a significant conversion of the
pitch content of the heavy hydrocarbon feedstock, the inventive
catalyst and process may provide for an incrementally greater yield
of distillate product than alternative catalysts and processes,
and, thus, they can provide greater economic benefits than other
alternatives. The inventive process may further provide for a
greater proportion of the pitch of the heavy hydrocarbon feedstock
that is converted to hydrocarbons having a boiling temperature less
than 538.degree. C. (1000.degree. F.) that is converted to
hydrocarbons boiling in the distillate boiling range of from
180.degree. C. (356.degree. F.) to 350.degree. C. (662.degree. F.),
or to distillate hydrocarbons. The inventive process, thus, can
provide a treated hydrocarbon product, wherein the proportion of
the converted pitch that includes hydrocarbons boiling in the
distillate boiling range exceeds 10 weight percent of the converted
pitch. The inventive process preferably provides a treated
hydrocarbon product that includes a proportion of converted pitch
that includes hydrocarbons boiling in the distillate boiling range
that exceeds 14 weight percent of the converted pitch, more
preferably, exceeding 16 weight percent of the converted pitch,
and, most preferably, exceeding 18 weight percent of the converted
pitch. This feature of the inventive process is particularly
beneficial when, in combination with other processing, an ultra low
sulfur diesel product is manufactured. This benefit is due to the
high amount of yielded distillate product having a relatively low
sulfur content which makes further severe hydroprocessing to make
ultra low sulfur diesel product unnecessary. Mild
hydrodesulfurization processing may, however, be required.
[0043] Another feature of the inventive process is that, in
addition to providing for desulfurization and pitch conversion, it
can provide for a significant reduction in the Micro-Carbon Residue
(MCR) content of the treated hydrocarbon product of the process
that utilizes the inventive catalyst. Micro-Carbon Residue content
refers to a quantity of carbon residue remaining after evaporation
and pyrolysis of a substrate and is determined by the testing
method ASTM D4530. In cases when the heavy hydrocarbon feedstock
has a significant MCR content, the inventive process can provide
for a treated hydrocarbon product having an MCR content that is
below that of the heavy hydrocarbon feedstock, and, in fact, the
inventive catalyst can provide for a greater reduction in the MCR
content than other prior art catalysts. This enhancement in the
ability to reduce the MCR content of a feedstock is particularly
advantageous in those situations when the inventive process is
providing for a treated hydrocarbon product that is to be used, or
portions thereof are to be used, as feedstock to a fluid catalytic
cracking (FCC) unit. This benefit is recognized in that the MCR
content of an FCC feedstock can significantly impact the amount of
such feedstock that the FCC unit is capable of processing. In
general, an FCC unit is able to process larger quantities of
feedstocks that have low levels of MCR content than those
feedstocks that have high levels of MCR content.
[0044] In the inventive process, the heavy hydrocarbon feedstock
may have an MCR value exceeding 6%. The inventive process is
particularly useful in the processing of a heavy hydrocarbon
feedstock that has an MCR value exceeding 8% and even exceeding
10%. The treated hydrocarbon product can have an MCR value of less
than 6%, preferably, less than 5%, and, more preferably, less than
4%.
[0045] One disadvantage from the use of the prior art
hydroconversion catalysts in the hydroconversion of heavy
hydrocarbon feedstocks is that the resulting product will tend to
have a low P-value. The P-value (peptization value) is a numerical
value that is an indicator of the flocculation tendency of the
asphaltenes contained in a hydrocarbon mixture. The determination
of the P-value is the method as described by J. J. Heithaus in
"Measurement and Significance of Asphaltene Peptization", Journal
of Institute of Petroleum, Vol. 48, Number 458, February 1962, pp.
45-53, which publication is incorporated herein by reference.
[0046] A high P-value for a hydrocarbon mixture indicates that it
is stable and a low P-value for a hydrocarbon mixture indicates
that it is not as stable in that there is a greater tendency for
precipitation of the asphaltenes contained the hydrocarbon mixture.
It is recognized that the P-value of a hydroconverted product tends
to decline as the percentage of the pitch component of a heavy
hydrocarbon feedstock that is converted increases, thus, indicating
a higher tendency for forming precipitates. But, it is one of the
advantages of the inventive catalyst and process that they provide
for a high amount of pitch conversion while still providing for a
treated hydrocarbon product that still has an acceptably high
P-value that exceeds 1.25. The catalyst and process can provide for
a pitch conversion of greater than 30 volume percent while still
providing for a treated hydrocarbon product having a P-value
greater than 1.25. It is preferred for the P-value of the treated
hydrocarbon product to exceed 1.5, more preferably, to exceed 1.75,
and, most preferably, exceeding 2, when the pitch conversion of the
heavy hydrocarbon feedstock that is provided by the inventive
catalyst and process exceeds 30 volume percent. In some instances,
the P-value of the heavy hydrocarbon feedstock may be less than
1.
[0047] The calcined mixture (catalyst) of the invention may be
employed as a part of any suitable reactor system that provides for
the contacting of the catalyst with the heavy hydrocarbon feedstock
under suitable hydroprocessing conditions that may include the
presence of hydrogen and an elevated total pressure and
temperature. Such suitable reaction systems can include fixed
catalyst bed systems, ebullating catalyst bed systems, slurried
catalyst systems, and fluidized catalyst bed systems. The preferred
reactor system is that which includes a fixed bed of the inventive
catalyst contained within a reactor vessel equipped with a reactor
feed inlet means, such as a feed nozzle, for introducing the heavy
hydrocarbon feedstock into the reactor vessel, and a reactor
effluent outlet means, such as an effluent outlet nozzle, for
withdrawing the reactor effluent or the treated hydrocarbon product
from the reactor vessel.
[0048] The inventive process generally operates at a
hydroprocessing (hydroconversion and hydrodesulfurization) reaction
pressure in the range of from 2298 kPa (300 psig) to 20,684 kPa
(3000 psig), preferably from 10,342 kPa (1500 psig) to 17,237 kPa
(2500 psig), and, more preferably, from 12,411 kPa (1800 psig) to
15,513 kPa (2250 psig). The hydroprocessing reaction temperature is
generally in the range of from 340.degree. C. (644.degree. F.) to
480.degree. C. (896.degree. F.), preferably, from 360.degree. C.
(680.degree. F.) to 455.degree. C. (851.degree. F.), and, most
preferably, from 380.degree. C. (716.degree. F.) to 425.degree. C.
(797.degree. F.).
[0049] The flow rate at which the heavy hydrocarbon feedstock is
charged to the reaction zone of the inventive process is generally
such as to provide a liquid hourly space velocity (LHSV) in the
range of from 0.01 hr to 3 hr.sup.1. The term "liquid hourly space
velocity", as used herein, means the numerical ratio of the rate at
which the heavy hydrocarbon feedstock is charged to the reaction
zone of the inventive process in volume per hour divided by the
volume of catalyst contained in the reaction zone to which the
heavy hydrocarbon feedstock is charged. The preferred LHSV is in
the range of from 0.05 hr.sup.-1 to 2 hr.sup.-1, more preferably,
from 0.1 hr.sup.-1 to 1.5 hr.sup.-1. and, most preferably, from 0.2
hr.sup.-1 to 0.7 hr.sup.-1.
[0050] It is preferred to charge hydrogen along with the heavy
hydrocarbon feedstock to the reaction zone of the inventive
process. In this instance, the hydrogen is sometime referred to as
hydrogen treat gas. The hydrogen treat gas rate is the amount of
hydrogen relative to the amount of heavy hydrocarbon feedstock
charged to the reaction zone and generally is in the range upwardly
to 1781 m.sup.3/m.sup.3 (10,000 SCF/bbl). It is preferred for the
treat gas rate to be in the range of from 89 m.sup.3/m.sup.3 (500
SCF/bbl) to 1781 m.sup.3/m.sup.3 (10,000 SCF/bbl), more preferably,
from 178 m.sup.3/m.sup.3 (1,000 SCF/bbl) to 1602 m.sup.3/m.sup.3
(9,000 SCF/bbl), and, most preferably, from 356 m.sup.3/m.sup.3
(2,000 SCF/bbl) to 1425 m.sup.3/m.sup.3 (8,000 SCF/bbl).
[0051] The following examples are presented to further illustrate
the invention, but they are not to be construed as limiting the
scope of the invention.
Example I
[0052] This Example I describes the preparation of Catalyst A.
[0053] Catalyst A
[0054] The Catalyst A was prepared by first combining 3209 parts by
weight 2% silica interstage alumina, 287 parts by weight nickel
nitrate (Ni(NO.sub.3).sub.2) dissolved in 99 parts by weight
deionized water, 269 parts by weight molybdenum trioxide powder
(MoO.sub.3), and 652 parts by weight crushed regenerated Ni/Mo/P
hydrotreating catalyst within a Muller mixer along with 130 parts
by weight 69.9% concentrated nitric acid and 30 grams of a
commercial extrusion aid. A total of 2948 parts by weight of water
was added to these components during the mixing. The components
were mixed for approximately 40 minutes. The mixture had a pH of
4.08 and an LOI of 55.7 weight percent. The mixture was then
extruded using 1.3 mm trilobe dies to form 1.3 trilobe extrudate
particles. The extrudate particles were then dried in air for a
period of several hours at a temperature of 100.degree. C.
[0055] Aliquot portions of the dried extrudate particles were
calcined in air each for a period of two hours at a temperature of
426.degree. C. (800.degree. F.), 566.degree. C. (1050.degree. F.),
677.degree. C. (1250.degree. F.), or 732.degree. C. (1350.degree.
F.). The final calcined mixture contained 2.2 weight percent nickel
metal (2.8 wt. % as NiO), 7.9 weight percent molybdenum metal
(11.85 wt. % as MoO.sub.3) and 85.45 weight percent 2%
silica/alumina. The following Table 1 presents certain properties
of the dried extrudate particles that were calcined at each of the
calcination temperatures. As may be seen from the pore properties
presented in Table 1, the percentage of the total pore volume
contained in the macropores having a pore diameter of 1000
Angstroms and larger is less than 1 percent.
TABLE-US-00001 TABLE 1 Properties of Dried Extrudate for Different
Calcination Conditions 426.degree. C. 566.degree. C. 677.degree. C.
732.degree. C. Properties (800.degree. F.) (1050.degree. F.)
(1250.degree. F.) (1350.degree. F.) Surface Area, m.sup.2/g 332 311
256 133.5 Hg Pore Size Dist. (Angs) less than 70 38.8 28.3 9.8 0.8
70-100 41.2 50.1 48.7 1.6 100-150 12.2 13.5 31.3 18.3 150-350 5.7
6.0 7.5 66.9 350-1000 1.9 1.9 2.0 11.1 1000+ 0.2 0.2 0.7 0.3 Total
Pore Volume, cc/g 0.551 0.564 0.596 0.702 Medium Pore Diameter, 76
81 96 128 .ANG.
Example II
Constant Sulfur Conversion Example
[0056] This Example II describes one of the methods used in testing
the catalysts described in Example I. This method provided for the
processing of a feedstock having a significant sulfur concentration
to yield a product having specified sulfur concentration. The
reactor temperature was adjusted to maintain the fixed sulfur
concentration in the reactor product.
[0057] Catalyst A and a commercially available hydrodemetallization
catalyst were loaded into a 1.5875 cm (5/8 inch) ID by 127 cm (50
inch) stainless steel tube reactor in a stacked bed arrangement
with 66.7 volume percent of the bed consisting of Catalyst A placed
at the bottom of the catalyst bed and 33.3 volume percent of the
bed consisting of the hydrodemetallization catalyst placed at the
top of the catalyst bed.
[0058] The tube reactor was equipped with thermocouples placed in a
0.635 cm (1/4 inch) thermowell inserted concentrically into the
catalyst bed, and the reactor tube was held within a 132 cm (52
inch) long 5-zone furnace with each of the zones being separately
controlled based on a signal from a thermocouple.
[0059] The catalyst of the stacked catalyst bed was activated by
feeding at ambient pressure a gas mixture of 5 vol. % H.sub.2S and
95 vol. % H.sub.2 to the reactor at a rate of 1.5 LHSV while
incrementally increasing the reactor temperature at a rate of
100.degree. F./hr up to 400.degree. F. The catalyst bed was
maintained at a temperature of 400.degree. F. for two hours and
then the temperature was incrementally increased at a rate of
100.degree. F./hr to a temperature of 600.degree. F., where it was
held for one hour followed again by an incremental increase in the
temperature at a rate of 75.degree. F./hr up to a temperature of
700.degree. F., where it was held for two hours before cooling the
catalyst bed temperature down to the ambient temperature. The
catalyst bed was then pressured with pure hydrogen at 1000 psig,
and the temperature of the catalyst bed was incrementally increased
at a rate of 100.degree. F./hr to 400.degree. F. The reactor was
then charged with feedstock while the temperature of the reactor
was held at 400.degree. F. for one hour. The catalyst bed
temperature was then incrementally increased at a rate of
50.degree. F./hr up 700.degree. F., from which point the run was
started.
[0060] The feedstock charged to the reactor was a Middle Eastern
long residue. The distillation properties of the feedstock as
determined by ASTM Method D7169 are presented in Table 2. Table 3
presents certain other properties of the feedstock.
TABLE-US-00002 TABLE 2 Distillation of Feedstock Wt. % Temp,
.degree. C. (.degree. F.) IBP 273 (523) 10 377 (711) 20 427 (801)
30 466 (871) 40 503 (937) 50 543 (1009) 60 588 (1090) 70 636 (1177)
80 695 (1283) 90 FBP 737 (1359)
TABLE-US-00003 TABLE 3 Other properties of the feedstock Property
Value Micro-Carbon Residue (MCR) 12.4 Sulfur (wt %) 4.544 Nickel
(ppm) 22 Vanadium (ppm) 75 1000.degree. F.+ (vol %) 51.3
[0061] The feedstock was charged to the reactor along with hydrogen
gas. The reactor was maintained at a pressure of 1900 psig and the
feedstock was charged to the reactor at a rate so as to provide a
liquid hourly space velocity (LHSV) of 0.33 hr.sup.-1 and the
hydrogen was charged at a rate of 3,000 SCF/bbl. The temperature of
the reactor was set so as to provide a product having a sulfur
content of 0.52 wt. %.
[0062] The inventive Catalyst A provides for a product having a
significantly reduced sulfur content over the sulfur content of the
feedstock processed. The sulfur content of the product was less
than 0.6 weight percent with the hydrodesulfurization activity of
the catalyst remaining stable over a significant time period.
Example III
[0063] This Example III describes the preparation of Catalyst
B.
[0064] Catalyst B
[0065] The Catalyst B was prepared by first dissolving 252 parts by
weight of Ni(NO.sub.3).sub.2.6H.sub.2O in 87 parts of DI water and
heating the solution until clear. Separately, 281 parts by weight
of MoO.sub.3 was combined with 3209 parts of alumina (2% silica in
98% alumina) and 639 parts of fresh, crushed and sieved commercial
Ni--Mo--P catalyst containing alumina and combined together in a
muller. With the muller running, 2905 parts of DI water, nickel
solution and 19 parts of nitric acid (69.8% concentration) were
added to the mull mix. The mixture was mulled for a total of 35
minutes. The mixture had a pH of 4.18 and an LOI of 56.6 weight
percent. The mixture was then extruded using 1.3 mm trilobe dies to
form 1.3 trilobe extrudate particles. The extrudate particles were
then dried in air for a period of several hours at a temperature of
100.degree. C.
[0066] Aliquot portions of the dried extrudate particles were
calcined in air each for a period of two hours at a temperature of
800.degree. F., 1000.degree. F., and 1200.degree. F. The final
calcined mixture contained 2.2 weight percent nickel metal (2.8 wt.
% as NiO), 7.9 weight percent molybdenum metal (11.85 wt. % as
MoO.sub.2), 0.34% of phosphorus (0.55 wt. % of phosphorus
pentaoxide), and 84.8 weight percent 2% silica/alumina. The
following Table 4 presents certain properties of the dried
extrudate particles that were calcined at each of the calcination
temperatures.
TABLE-US-00004 TABLE 4 Properties of Dried Extrudate for Different
Calcination Conditions 426.degree. C. 538.degree. C. 649.degree. C.
Properties (800.degree. F.) (1000.degree. F) (1200.degree. F) Crush
Strength, lbs/mm 5.63 5.72 5.03 Water Pore Volume, ml/g 0.63 0.61
0.64 Hg Pore Size Dist. - Hg <70 A 34.1 24.2 11.2 70-100 A 60.4
69.3 75.4 100-130 A 2.6 3.2 9.6 130-150 0.6 0.7 0.9 150-180 A 0.8
0.8 0.8 180-350 A 1.4 1.4 1.6 350 A+ 0.1 0.4 0.5 Medium Pore
Diameter, .ANG. 74 79 90 Total Pore Volume, Hg, cc/g 0.57 0.60 0.59
Surface Area, m2/g 323 315 272
Example IV
Constant Reactor Temperature Example
[0067] This Example describes one of the methods used in testing
the catalyst described in Example III. This method provided for the
processing of a feedstock having significant sulfur and pitch
contents to yield a product having reduced sulfur and pitch
contents and product liquid that is stable. The reactor temperature
was kept constant in conducting these reactions and the sulfur
content, the pitch content and the product liquid quality were
monitored.
[0068] A multi-barrel reactor was used to conduct this test. The
heating block contained four parallel tube reactors each of which
was 0.59 inch ID by 23.625 inches in length 321 stainless steel
tube. A single temperature controller was used to control the
heater block, which encased all four of the reactors. Each of the
tube reactors was loaded in a stacked bed arrangement with 30
cm.sup.3 of Catalyst B placed at the bottom of the catalyst bed and
6 cm.sup.3 of a commercially available hydrodemetallization
catalyst placed at the top of the catalyst bed. One of the reactors
was loaded with a commercially available alumina supported nickel
and molybdenum hydrodesulfurization catalyst product of Criterion
Catalyst Company designated as RN-650 (Catalyst C) as used in the
other runs and a commercial HDM catalyst in the remaining bottom
section.
[0069] The catalyst of the stacked catalyst bed was activated by
feeding at ambient pressure a gas mixture of 5 vol. % H.sub.2S and
95 vol. % H.sub.2 to the reactor at a rate of 30 SLPH while
incrementally increasing the reactor temperature at a rate of
100.degree. F./hr up to 400.degree. F. The catalyst bed was
maintained at a temperature of 400.degree. F. for two hours, and,
then, the temperature was incrementally increased at a rate of
100.degree. F./hr to a temperature of 600.degree. F., where it was
held for two hours followed again by an incremental increase in the
temperature at a rate of 50.degree. F./hr up to a temperature of
700.degree. F., where it was held for two hours before cooling the
catalyst bed temperature of 400.degree. F.
[0070] The feedstock charged to the reactor was a Middle Eastern
crude. The distillation properties of the feedstock as determined
by ASTM Method D7169 are presented in Table 5. Table 6 presents
certain other properties of the feedstock.
TABLE-US-00005 TABLE 5 Distillation of Feedstock Wt. % Temp,
.degree. C. (.degree. F.) IBP 10 351 (664) 20 399 (750) 30 437
(819) 40 472 (882) 50 510 (950) 60 554 (1029) 70 602 (1116) 80 657
(1215) 90 725 (1337) FBP 733 (1351)
TABLE-US-00006 TABLE 6 Other properties of the feedstock Property
Value Micro-Carbon Residue (MCR) 11.4 Sulfur (wt %) 4.012 Nickel
(ppm) 16.7 Vanadium (ppm) 59 1000.degree. F.+ (vol %) 43.5
[0071] Feedstock was charged to the reactors along with hydrogen
gas. The reactors were maintained at a pressure of 1900 psig, and
the feedstock was charged to the reactors at a rate so as to
provide a liquid hourly space velocity (LHSV) of 0.6 hr.sup.-1 and
the hydrogen was charged at a rate of 3,000 SCF/bbl. The
temperatures of the reactors were fixed at 725.degree. F. for
approximately a month and then raised to 752.degree. F. for the
remaining duration.
[0072] Presented in FIG. 1 are plots (the estimated linear function
based on experimental data) of the P-value of product as a function
of pitch conversion of the feedstock for the process using the
inventive Catalyst B and for the comparison Catalyst C. As may be
observed from the data presented in FIG. 1, the inventive Catalyst
B provides for a product stability as reflected by the P-value that
is significantly higher than comparison Catalyst C. At both the
temperatures of operation, the inventive catalyst provides for a
higher pitch conversion and a higher product P-value. The
comparison catalyst provides for a less stable product when pitch
conversion approaches 65% than does the inventive catalyst, which
provides for a stable product at a significantly higher pitch
conversion.
Example V
[0073] This Example V describes the preparation of Catalyst D and a
comparison Catalyst E.
[0074] Catalyst D
[0075] The Catalyst D was prepared by first combining 4047 parts by
weight 2% silica interstage alumina, 378 parts by weight nickel
nitrate (Ni(NO.sub.3).sub.2) dissolved in 138 parts by weight
deionized water, and 418 parts by weight molybdenum trioxide powder
(MoO.sub.3) within a Muller mixer. A total of 3807 parts by weight
of water was added to these components during the mixing. The
components were mixed for approximately 45 minutes. The mixture had
a pH of 4.75 and an LOI of 59.6 weight percent. The mixture was
then extruded using 1.3 mm trilobe dies to form 1.3 trilobe
extrudate particles. The extrudate particles were then dried in air
for a period of several hours at a temperature of 100.degree.
C.
[0076] Aliquot portions of the dried extrudate particles were
calcined in air each for a period of two hours at a temperature of
1000.degree. F., 1250.degree. F., 1300.degree. F., or 1350.degree.
F. The final calcined mixture contained 2.2 weight percent nickel
metal (2.8 wt. % as NiO), 7.9 weight percent molybdenum metal
(11.85 wt. % as MoO.sub.3) and 85.45 weight percent 2%
silica/alumina. The following Table 7 presents certain properties
of the dried extrudate particles that were calcined at a
calcination temperature of 1250.degree. F.
TABLE-US-00007 TABLE 7 Properties of Dried and Calcined Extrudate
Properties 677.degree. C. (1250.degree. F.) Crush Strength, lbs/mm
3.81 Water Pore Volume, ml/g 0.75 Hg Pore Size Dist. - Hg <70 A
5.5 70-100 A 53.6 100-130 A 33.6 130-150 2.1 150-180 A 1.4 180-350
A 2.6 350 A+ 1.2 Medium Pore Diameter, .ANG. 98 Total Pore Volume,
Hg, cc/g 0.695 Surface Area, m2/g 261
[0077] Catalyst E
[0078] The comparison Catalyst E was made by combining 4104 parts
of alumina powder with 127 parts of nickel as nickel hydroxide and
mulling briefly. With muller running, added 4104 parts of deionized
water were added and muller mix mulled for 55 minutes. Then, the
molybdenum as ammonium di-molybdate (i.e. a molybdenum salt) and
mulled for additional five minutes. The mixture had a pH of 7.23
and an LOI of 59 weight percent. The mixture was then extruded
using 1.3 mm trilobe dies to form 1.3 trilobe extrudate particles.
The extrudate particles were then dried in air for a period of
several hours at a temperature of 100.degree. C.
[0079] Aliquot portions of the dried extrudate particles were
calcined in air each for a period of two hours at a temperature of
1000.degree. F. and 1200.degree. F. The final calcined mixture
contained 2.2 weight percent nickel metal (2.8 wt. % as NiO), 7.9
weight percent molybdenum metal (11.85 wt. % as MoO.sub.3) and
85.35 weight percent alumina. The following Table 8 presents
certain properties of the dried extrudate particles that were
calcined at a calcination temperature of 1250.degree. F.
TABLE-US-00008 TABLE 8 Properties of Dried and Calcined Extrudate
Properties 649.degree. C. (1200.degree. F.) Crush Strength, lbs/mm
3.57 Water Pore Volume, ml/g 0.87 Hg Pore Size Dist. <70 A 3.3
70-100 A 29.8 100-130 A 58.9 130-150 2.6 150-180 A 1.6 180-350 A
2.3 350 A+ 1.5 Total Pore Volume, cc/g 0.69 Medium Pore Diameter,
.ANG. 105 BET Surface Area, m2/g 254.1
Example VI
Constant Temperature Long-Term Testing
[0080] This Example VI describes one of the methods used in testing
the catalysts described in Example V. This method provided for the
processing of a feedstock having significant sulfur and MCR
contents to yield a product having reduced sulfur content. The
reactor temperature was kept constant in conducting these reactions
and the sulfur content of the product was monitored.
[0081] A multi-barrel reactor was used to conduct this test. The
heating block contained four parallel tube reactors each of which
was 0.59 inch ID by 23.625 inches in length 321 stainless steel
tube. A single temperature controller was used to control the
heater block, which encased all four of the reactors. Each of the
tube reactors was loaded in a stacked bed arrangement with 30
cm.sup.3 of the catalyst to be test (either Catalyst D or E) placed
at the bottom of the catalyst bed and 6 cm.sup.3 of a commercially
available hydrodemetallization catalyst placed at the top of the
catalyst bed.
[0082] The catalyst of the stacked catalyst bed was activated by
feeding at ambient pressure a gas mixture of 5 vol. % H.sub.2S and
95 vol. % H.sub.2 to the reactor at a rate of 30 SLPH while
incrementally increasing the reactor temperature at a rate of
100.degree. F./hr up to 400.degree. F. The catalyst bed was
maintained at a temperature of 400.degree. F. for two hours, and,
then, the temperature was incrementally increased at a rate of
100.degree. F./hr to a temperature of 600.degree. F., where it was
held for two hours followed again by an incremental increase in the
temperature at a rate of 50.degree. F./hr up to a temperature of
700.degree. F., where it was held for two hours before cooling the
catalyst bed temperature of 400.degree. F.
[0083] The feedstock charged to the reactor was a Middle Eastern
crude. The distillation properties of the feedstock as determined
by ASTM Method D7169 are presented in Table 9. Table 10 presents
certain other properties of the feedstock.
TABLE-US-00009 TABLE 9 Distillation of Feedstock Wt. % Temp,
.degree. C. (.degree. F.) IBP 10 351 (664) 20 399 (750) 30 437
(819) 40 472 (882) 50 510 (950) 60 554 (1029) 70 602 (1116) 80 657
(1215) 90 725 (1337) FBP 733 (1351)
TABLE-US-00010 TABLE 10 Other properties of the feedstock Property
Value Micro-Carbon Residue (MCR) 11.4 Sulfur (wt %) 4.012 Nickel
(ppm) 16.7 Vanadium (ppm) 59 1000.degree. F.+ (vol %) 43.5
[0084] Feedstock was charged to the reactors along with hydrogen
gas. The reactors were maintained at a pressure of 1900 psig, and
the feedstock was charged to the reactors at a rate so as to
provide a liquid hourly space velocity (LHSV) of 0.6 hr.sup.-1 and
the hydrogen was charged at a rate of 3,000 SCF/bbl. The
temperatures of the reactors were fixed at either 725.degree. F. or
752.degree. F.
[0085] Presented in FIG. 2 are plots of the relative values for the
calculated Weight Average Bed Temperature (WABT) that would be
required for an 88 wt % hydrodesulfurization of the feedstock as a
function of run time for the inventive Catalyst D and the
comparison Catalyst E. As may be observed from the data presented
in FIG. 1, the inventive Catalyst D exhibits catalytic activity
over time that is significantly higher than the activity of the
comparison Catalyst E.
* * * * *