Note: Descriptions are shown in the official language in which they were submitted.
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DESULFURIZATION AND NOVEL SORBENTS FOR SAME
BACKGROUND OF THE INVENTION
This invention relates to a sorbent composition, a process of making a sorbent
composition, and to a process of using a sorbent composition for the removal
of sulfur
from a hydrocarbon-containing fluid.
The need for cleaner burning fuels has resulted in a continuing world-wide
effort
to reduce sulfur levels in hydrocarbon-containing fluids such as gasoline and
diesel fuels.
The reduction of sulfur in such hydrocarbon-containing fluids is considered to
be a means
for improving air quality because of the negative impact the. sulfur has on
the performance
of sulfur-sensitive items such as automotive catalytic converters. The
presence of oxides
of sulfur in automotive engine exliaust inhibits and may irreversibly poison
noble metal
catalysts in the converter. Emissions from an inefficient or poisoned
converter contain
levels of non-combusted, non-methane hydrocarbons, oxides of nitrogen, and
carbon
monoxide. Such emissions are catalyzed by sunlight to form ground level ozone,
more
commonly referred to as smog.
Most of the sulfur in a hydrocarbon-containing fluid such as gasoline comes
from
thermally processed gasolines. Thermally processed gasolines such as, for
example,
thermally cracked gasoline, visbreaker gasoline, coker gasoline and
catalytically cracked
gasoline (hereinafter collectively referred to as "craclced-gasoline")
contains, in part,
olefins, aromatics, sulfur, and sulfur-containing compounds.
Since most gasolines, such as for example automobile gasolines, racing
gasolines,
aviation gasolines, boat gasolines, and the like contain a blend of, at least
in part,
cracked-gasoline, reduction of sulfur in cracked-gasoline will inherently
serve to reduce
the sulfur levels in most gasolines such as, for example, automobile
gasolines, racing
gasolines, aviation gasolines, boat gasolines, and the like.
The public discussion about gasoline sulfur has not centered on whether or not
sulfur levels should be reduced. A consensus has emerged that lower sulfur
gasoline
reduces automotive emissions and improves air quality. Thus, the real debate
has focused
on the required level of reduction, the geographical areas in need of lower
sulfur gasoline,
and the time frame for implementation.
As the concern over the impact of automotive air pollution continues,.it is
clear
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that further efforts to reduce the sulfur levels in hydrocarbon-containing
fluids such as
gasolines, more particularly automotive gasolines, will be required. While the
current
gasoline products contain about 330 arts per million (ppm) sulfur by weight,
the U. S.
Environmental Protection Agency recently issued regulations requiring the
average sulfur
content in gasoline to be less than 30 ppm average with an 80 ppm maximum. By
2006,
the standards will effectively require every blend of gasoline sold in the
United States to
meet the 30 ppm level.
In addition to the need to be able to produce low sulfur content automotive
fuels,
there is also a need for a process which will have a minimal effect on the
olefin content of
such fuels so as to maintain the octane number (both research and motor octane
number).
Such a process would be desirable since saturation of olefins greatly affects
the octane
number. Such adverse effect on olefin content is generally due to the severe
condition
normally employed, such as during hydrodesulfurization, to remove thiophenic
compounds (such as, for example, thiophenes, benzothiophenes, alkyl
thiophenes, alkyl
benzothiophenes, alkyl dibenzothiophenes and the lilce) which are some of the
most
difficult sulfur-containing compounds to be removed from cracked-gasoline. In
addition,
there is a need to avoid a system wherein the conditions are such that the
aromatic content
of the craclced-gasoline is also lost through saturation. Thus, there is a
need for a process
wherein desulfurization is achieved and the octane number is maintained.
In addition to the need fox removal of sulfur from hydrocarbon-containing
fluids
such as craclced-gasoline, there is also presented to the petroleum industry a
need to
reduce the sulfur content in other hydrocarbon-containing fluids such as
diesel fuel. In
removing sulfur from diesel fuel by hydrodesulfurization, the cetane is
improved but there
is a large cost in hydrogen consumption. Such hydrogen is consumed by both
hydro-
desulfurization and aromatic hydrogenation reactions.
Thus, there is a need for a process of desulfurization without a significant
consumption of hydrogen so as to provide a more economical process for the
treatment of
hydrocarbon-containing fluids such as cracked gasoline and diesel fuel.
As a result of the laclc of success in providing a successful and economically
feasible process for the reduction of sulfur levels in hydrocarbon-containing
fluids such as
cracked-gasoline and diesel fuel, it is apparent that there is still a need
for a better process
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for the desulfurization of such hydrocarbon-containing fluids which has
minimal effect on
octane levels while achieving high levels of sulfur removal.
Traditionally, sorbent compositions used in processes for the removal of
sulfur
from hydrocarbon-containing fluids have been agglomerates utilized in fixed
bed
applications. Because of the various process advantages of fluidized beds,
hydrocarbon-
containing fluids are sometimes used in fluidized bed reactors. Fluidized bed
reactors
have advantages over fixed bed reactors such as better heat transfer and
better pressure
drop. Fluidized bed reactors generally use reactants that are particulates.
The size of
these particulates is generally in the range of about 1 micrometer to about
1000
micrometers. However, the reactants used generally do not have sufficient
attrition
resistance for all applications. Consequently, finding a sorbent with
sufficient attrition
resistance that removes sulfur from these hydrocarbon-containing fluids and
that can be
used in fluidized, transport, moving, or fixed bed reactors is desirable and
would be of
significant contribution to the art and to the economy.
SUMMARY OF THE INVENTION
It is desirable to provide a sorbent composition that can be used for the
removal of
sulfur from a hydrocarbon-containing fluid such as cracked-gasoline or diesel
fuel.
Again it is desirable to provide a sorbent composition comprising a promoter
component selected from the group consisting of metals, metal oxides, and the
like and
combinations thereof.
Yet again it is desirable to provide a method of making a novel sorbent
composition which is useful in the desulfurization of a hydrocarbon-containing
fluid such
as cracked-gasoline or diesel fuel.
Once again it is desirable to provide a novel sorbent composition having an
enhanced attrition resistance when utilized in the desulfurization of a
hydrocarbon-containing fluid such as cracked-gasoline or diesel fuel.
Again it is desirable to employ such novel sorbent composition and a process
for
the removal of sulfur, such as that found in sulfur-containing compounds, from
a
hydrocarbon-containing fluid, such as cracked-gasoline or diesel fuel, which
minimizes
the consumption of hydrogen and minimizes the saturation of olefins and
aromatics
contained in such hydrocarbon-containing fluid.
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Yet again it is desirable to provide a desulfurized cracked-gasoline that
contains
less than about 100 parts per million of sulfur based on the weight of the
desulfurized
cracked-gasoline and which contains essentially the same amount of olefins and
aromatics
as are in the cracked-gasoline from which such desulfurized cracked-gasoline
was made.
Again it is desirable to provide a desulfurized diesel fuel wherein the cetane
is
improved and such desulfurized diesel fuel contains essentially the same
amount of
olefins and aromatics as are in the diesel fuel from which such desulfurized
diesel fuel
was made.
The present invention is based upon our discovery that through the utilization
of
an attrition-resistance-enhancing component present in an attrition-resistance-
enhancing
amount in a sorbent composition, there is achieved a novel sorbent composition
which
permits the ready removal of sulfur from a hydrocarbon-containing fluid such
as
cracked-gasoline or diesel fuel with a minimal effect on the octane rating of
the treated
hydrocarbon-containing fluid and where such sorbent composition has an
enhanced
attrition resistance compared to a sorbent composition that does not contain
such
attrition-resistance-enhancing component.
In one aspect of the present invention there is provided a novel sorbent
composition suitable for the desulfurization of a hydrocarbon-containing fluid
such as
cracked-gasoline or diesel fuel. Such novel sorbent composition comprises a
support
component, a promoter component selected from the group consisting of metals,
metal
oxides, and the like and combinations thereof wherein the valance of such
promoter
component is substantially reduced and such reduced-valence promoter component
is
present in an amount which is effective in the removal of sulfur from a
hydrocarbon-
containing fluid, and an attrition-resistance-enhancing component present in
an amount
which is effective in enhancing the attrition resistance of a sorbent
composition of the
present invention.
In accordance with another aspect of the present invention, there is provided
a
process for the preparation of a novel sorbent composition which comprises:
contacting a
support component, preferably such support component comprises zinc oxide,
silica, and
alumina, and an attrition- resistance-enhancing component to form a mixture
selected
from the group consisting of a wet mix, a dough, a paste, a slurry, and the
like;
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particulating such mixture so as to form a particulate selected from the group
consisting
of a granulate, an extrudate, a tablet, a sphere, a pellet, a microsphere, and
the like; drying
such particulate to form a dried particulate; calcining such dried particulate
to form a
calcined particulate; incorporating a promoter component selected from the
group
consisting of metals, metal oxides, and the like and combinations thereof on,
in, or with
such dried and calcined particulate to form a promoted particulate; drying
such promoted
particulate to form a dried promoted particulate; calcining such dried
promoted particulate
to form a calcined promoted particulate; and reducing such calcined promoted
particulate
with a suitable reducing agent, such as hydrogen, so as to produce a sorbent
composition
having a substantially zero-valence promoter component incorporated on, in, or
with such
sorbent composition in an amount which is effective in removing sulfur from a
hydrocarbon-containing fluid. The attrition resistance of the sorbent
composition is
enhanced by providing an effective concentration of an attrition-resistance-
enhancing
component.
In accordance with a further aspect of the present invention, there is
provided a
process for the desulfuxization of a hydrocarbon-containing fluid selected
from the group
consisting of cracleed-gasoline, diesel fuel, and the lilce and combinations
thereof which
comprises desulfurizing in a desulfurization zone such hydrocarbon-containing
fluid with
a sorbent composition, separating the desulfurized hydrocarbon-containing
fluid and the
sulfurized sorbent composition, regenerating at least a portion of the
sulfurized sorbent
composition to produce a regenerated, desulfurized sorbent composition;
activating at
least a portion of the regenerated, desulfurized sorbent composition to
produce an
activated, regenerated, desulfurized sorbent composition; and thereafter
returning at least
a portion of the activated, regenerated, desulfurized sorbent composition to
the
desulfurization zone.
Other objectives and advantages of the present invention will be apparent from
the
detailed description of the invention and the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
The term "gasoline" denotes a mixture of hydrocarbons boiling in the range of
from about 100°F to about 400°F, or any fraction thereof.
Examples of suitable gasoline
include, but are not limited to, hydrocarbon streams in refineries such as
naphtha, straight-
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run naphtha, coker naphtha, catalytic gasoline, visbreaker naphtha, alkylate,
isomerate,
reformate, and the like and combinations thereof.
The term "cracked-gasoline" denotes a mixture of hydrocarbons boiling in the
range of from about 100°F to about 400°F, or any fraction
thereof, that are products from
either thermal or catalytic processes that crack larger hydrocarbon molecules
into smaller
molecules. Examples of suitable thermal processes include, but are not limited
to,
coking, thermal cracking, visbreaking and the like and combinations thereof.
Examples
of suitable catalytic craclcing processes include, but are not limited to
fluid catalytic
cracking, heavy oil cracking, and the like and combinations thereof. Thus,
examples of
suitable cracked-gasoline include, but are not limited to, coker gasoline,
thermally
cracked gasoline, visbreaker gasoline, fluid catalytically cracked gasoline,
heavy oil
cracked gasoline, and the like and combinations thereof. In some instances,
the
cracked-gasoline may be fractionated and/or hydrotreated prior to
desulfurization when
used as a hydrocarbon-containing fluid in a process of the present invention.
1 S The term "diesel fuel" denotes a mixture of hydrocarbons boiling in the
range of
from about 300°F to about 750°F, or any fraction thereof.
Examples of suitable diesel
fuels include, but are not limited to, light cycle oil, lcerosene, jet fuel,
straight-run diesel,
hydrotreated diesel, and the like and combinations thereof.
The term "sulfur" denotes sulfur in any form such as elemental sulfur or a
sulfur
compound normally present in a hydrocarbon-containing fluid such as cracked
gasoline or
diesel fuel. Examples of sulfur which can be present during a process of the
present
invention, usually contained in a hydrocarbon-containing fluid, include, but
are not
limited to, hydrogen sulfide, carbonyl sulfide (COS), carbon disulfide (CSZ),
mercaptans
(RSH), organic sulfides (R.-S-R), organic disulfides (R-S-S-R), thiophene,
substituted
thiophenes, organic trisulfides, organic tetrasulfides, benzothiophene, alkyl
thiophenes,
allcyl benzothiophenes, alkyl dibenzothiophenes, and the like and combinations
thereof as
well as the heavier molecular weights of same which are normally present in a
diesel fuel
of the types contemplated for use in a process of the present invention,
wherein each R
can be an alkyl or cycloalkyl or aryl group containing one carbon atom to ten
carbon
atoms.
The term "fluid" denotes gas, liquid, vapor, and combinations thereof.
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The term "gaseous" denotes that state in which the hydrocarbon-containing
fluid,
such as cracked-gasoline or diesel fuel, is primarily in a gas or vapor phase.
The term "attrition resistance" denotes the attrition resistance of a sorbent
composition of the pxesent invention measured as the Davison Index. The term
"Davison
Index" (DI) refers to a measure of a sorbent's resistance to particle size
reduction under
controlled conditions of turbulent motion. The Davison Index represents the
weight
percent of the over 20 micrometer particle size fraction which is reduced to
particle sizes
of less than 20 micrometers under test conditions. The Davison Index is
measured using
a Jet cup attrition determination method. The Jet cup attrition determination
method
involves screening a 5 gram sample of sorbent to remove particles in the 0 to
20
micrometer size range. The particles above 20 micrometers are then subjected
to a
tangential j et of air at a rate of 21 liters per minute introduced through a
0.0625 inch
orifice fixed at the bottom of a specially designed Jet cup (1" LD. X 2"
height) for a
period of 1 hour. The Davison Index (DI) is calculated as follows:
DI = Weight of 0 to 20 micrometer material formed during tes X 100 x
correction factor
Weight of original 20+ micrometer fraction being tested
Correction factor (presently 0.3) is determined by using a known calibration
standard to adjust for differences in jet cup dimensions and wear.
A sorbent composition of the present invention having an attrition-resistance-
enhancing amount of an attrition-resistance-enhancing component has a Davison
Index
value generally less than about 30. Preferably, the sorbent composition has a
Davison
Index value in the range of from about 1 to about 25. More preferably, the
sorbent
composition has a Davison Index value in the range of from 5 to 20.
A sorbent composition of the present invention comprising an attrition-
resistance-
enhancing component has an enhanced attrition resistance when compared to
sorbent
compositions which do not have such attrition-resistance-enhancing component.
The term "support component" denotes any component or combination of
components which can be used as a support for a sorbent composition of the
present
invention to help promote a desulfurization process of the present invention.
Examples of
a suitable support component include, but are not limited to, zinc oxide and
any suitable
inorganic and organic carriers and the like and combinations thereof. Examples
of
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suitable inorganic carriers include, but are not limited to, silica, silica
gel, alumina,
diatomaceous earth, expanded perlite, kieselguhr, silica-alumina, titania,
zirconia, zinc
aluminate, zinc titanate, zinc silicate, magnesium aluminate, magnesium
titanate,
synthetic zeolites, natural zeolites, and the like and combinations thereof.
Examples of
suitable organic carriers include, but are not limited to, activated carbon,
coke, charcoal,
carbon-containing molecular sieves, and the like and combinations thereof. A
preferred
support component comprises zinc oxide, silica, and alumina.
The term "promoter component" denotes any component which can be added to a
sorbent composition of the present invention to help promote a desulfurization
process of
the present invention. Examples of suitable promoter components include, but
are not
limited to, metals, metal oxides, and the like and combinations thereof.
The term "metal" denotes metal in any form such as elemental metal or a metal-
containing compound.
The term "metal oxide" denotes metal oxide in any form such as a metal oxide
or a
metal oxide precursor.
The term "attrition-resistance-enhancing component" denotes any component
which can be added to a sorbent composition of the present invention to
enhance the
attrition resistance of such sorbent composition compared to a sorbent
composition which
does not contain such attrition-resistance-enhancing component. Examples of a
suitable
attrition-resistance-enhancing component include, but are not limited to,
clays, high
alumina cements, natural cements, Portland cement, calcium aluminate, calcium
silicate,
talc, and the like and combinations thereof. The term "clay" denotes any clay
which can
be used as an attrition-resistance-enhancing component of a sorbent
composition of the
present invention. Examples of a suitable clay include, but are not limited
to, bentonite,
sodium bentonite, acid-washed bentonite, atapulgite, china clay, kaolinite,
montmorillonite, illite, halloysite, hectonite, sepiolite, and the like and
combinations
thereof. Preferably, such attrition-resistance-enhancing component comprises a
clay.
More preferably, such attrition-resistance-enhancing component is selected
from the
group consisting of bentonite, sodium bentonite, acid-washed bentonite, and
the like and
combinations thereof. Most preferably, such attrition-resistance-enhancing
component is
bentonite.
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During the preparation of a sorbent composition of the present invention, the
promoter component selected from the group consisting of metals, metal oxides,
and the
lilce and combinations thereof may initially be in the form of a metal-
containing
compounds) and/or a metal oxide precursor(s). It should be understood that
when the
promoter component is initially a metal-containing compounds) and/or a metal
oxide
precursor(s), a portion of, or all of, such compounds) and/or precursors) may
be
converted to the corresponding metal or metal oxide of such compounds) andlor
precursors) during the inventive processes) disclosed herein.
The term "reduced-valence promoter component" denotes that a substantial
portion of the valence of such promoter component is reduced, preferably to a
value of
zero.
When an attrition-resistance-enhancing component is distributed throughout a
particulate composition, comprising a support component, preferably such
support
component comprises zinc oxide, silica, and alumina, and a promoter component,
there is
provided a novel sorbent composition of the present invention which permits
the removal
of sulfur from a hydrocarbon-containing fluid, such as cracked-gasoline or
diesel fuel,
without having a significant adverse effect on the olefin content of such
treated
hydrocarbon-containing fluid, thus avoiding a significant reduction in octane
values of
such treated hydrocarbon-containing fluid. Moreover, the use of a novel
sorbent
composition of the present invention results in a significant reduction of the
sulfur content
of the treated hydrocarbon-containing fluid. Further, a novel sorbent
composition of the
present invention has an enhanced attrition resistance when compared to a
sorbent
composition which does not have such attrition-resistance-enhancing component.
When a support component generally comprising zinc oxide and any inorganic or
organic carrier, preferably comprising zinc oxide, silica and alumina, is
used, the zinc
oxide used in the preparation of a sorbent composition of the present
invention can be
either in a form of zinc oxide such as powdered zinc oxide, or in the form of
one or more
zinc compounds that are convertible to zinc oxide under the conditions of
preparation
described herein. Examples of suitable zinc compounds include, but are not
limited to,
zinc sulfide, zinc sulfate, zinc hydroxide, zinc carbonate, zinc acetate, zinc
nitrate, and the
like and combinations thereof. Preferably, the zinc oxide is in the form of
powdered zinc
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oxide.
When a preferred support component comprising zinc oxide, silica, and alumina
is
used, the silica used in the preparation of a sorbent composition of the
present invention
can be either in the form of silica or in the form of one or more silicon
compounds. Any
suitable type of silica may be employed in preparing a sorbent composition of
the present
invention. Examples of suitable types of silica include, but are not limited
to, diatomite,
expanded perlite, silicalite, silica colloid, flame-hydrolyzed silica,
hydrolyzed silica, silica
gel, precipitated silica and the like and combinations thereof. In addition,
silicon
compounds that are convertible to silica such as silicic acid, ammonium
silicate and the
like and combinations thereof can also be employed. Preferably, the silica is
in the form
of diatomite or expanded perlite.
When a preferred support component comprising zinc oxide, silica, and alumina
is
used, the alumina used in preparing a sorbent composition of the present
invention can be
present in the source of silica, can be any suitable commercially available
alumina
material (including, but not limited to, colloidal alumina solutions, hydrated
aluminas,
and, generally, those alumina compounds produced by the dehydration of alumina
hydrates), or both. The preferred alumina is a hydrated alumina such as, but
not limited
to, boehmite or pseudoboehmite.
The promoter component used in preparing a sorbent composition of the present
invention can be any metal, metal oxide, and the like and combinations thereof
in any
form which is effective in desulfurizing a hydrocarbon-containing fluid
according to a
process of the present invention. Generally such promoter component is
selected from the
group consisting of metals, metal oxides, and the like and combinations
thereof including
compounds which contain such metals and metal oxides. Examples of suitable
metals
include, but are not limited to, cobalt, nickel, iron, manganese, copper,
zinc,
molybdenum, tungsten, silver, tin, vanadium, antimony, and the lilce and
combinations
thereof. Examples of suitable metal oxides include, but are not limited to,
cobalt oxides,
nickel oxides, iron oxides, manganese oxides, copper oxides, zinc oxides,
molybdenum
oxides, tungsten oxides, silver oxides, tin oxides, vanadium oxides, antimony
oxides, and
the like and combinations thereof. Generally such metals axe contained in
metal-
containing compounds which can be used to incorporate the metal of such metal-
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containing compounds on, in, or with a dried and calcined particulate material
to thereby
form a dried and calcined promoted particulate material which can then be
further dried
and calcined, and preferably reduced, to thereby form a sorbent composition of
the
present invention.
Some examples of the form which such metals can be in include, but are not
limited to, metal acetates, metal carbonates, metal nitrates, metal sulfates,
metal
thiocyanates, and the like and combinations thereof. Preferably, the promoter
component
is selected from the group consisting of nickel, cobalt, and the like and
combinations
thereof. More preferably, the promoter component is nickel. In a preferred
method of
making process of the present invention, the sorbent composition is promoted
with a
precursor of a nickel oxide such as nickel nitrate, more preferably nickel
nitrate
hexahydrate.
When the support component comprises zinc oxide and any inorganic or organic
Garner, preferably comprising zinc oxide, silica and alumina, the zinc oxide
will generally
be present in a sorbent composition of the present invention in an amount in
the range of
from about 10 to about 90 weight percent zinc oxide based on the total weight
of the
sorbent composition, preferably in an amount in the range of from about 15 to
about 60
weight percent zinc oxide and, more preferably, in an amount in the range of
from 20 to
55 weight percent zinc oxide.
When the support component comprises a preferred support component
comprising zinc oxide, silica, and alumina, the silica will generally be
present in a sorbent
composition of the present invention in an amount in the range of from about 5
to about
85 weight percent silica based on the total weight of the sorbent composition,
preferably
in an amount in the range of from about 10 to about 60 weight percent silica
and, more
preferably, in an amount in the range of from 15 to 55 weight percent silica.
When the support component comprises a preferred support component
comprising zinc oxide, silica, and alumina, the alumina will generally be
present in a
sorbent composition of the present invention in an amount in the range of from
about 0.1
to about 30 weight percent alumina based on the total weight of the sorbent
composition,
preferably in an amount in the range of from about 1 to about 20 weight
percent alumina
and, more preferably, in an amount in the range of from S to 15 weight percent
alumina.
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The attrition-resistance-enhancing component will generally be present in an
attrition-resistance-enhancing amount which is effective in providing a
sorbent
composition of the present invention having an enhanced attrition resistance
compared to
a sorbent composition which does not have such attrition-resistance-enhancing
S component. The attrition-resistance-enhancing component will generally be
present in a
sorbent composition of the present invention in an amount in the range of from
about 1 to
about 30 weight percent attrition-resistance-enhancing component based on the
total
weight of the sorbent composition, preferably in an amount in the range of
from about S
to about 20 weight percent attrition-resistance-enhancing component and, more
preferably, in an amount iri the range of from S to 1 S weight percent
attrition-resistance-
enhancing component. .
The promoter component will generally be present in a sorbent composition of
the
present invention in an amount in the range of from about S to about SO weight
percent
promoter component based on the total weight of the sorbent composition,
preferably in
1 S an amount in the range of from about 8 to about 4S weight percent promoter
component
and, more preferably, in an amount in the range of from 10 to 40 weight
percent promoter
component. When the promoter component comprises a combination of metals,
metal
oxides, and the like, such as a preferred bimetallic promoter component, the
bimetallic
promoter component should comprise a weight ratio of the two metals forming
such
bimetallic promoter component in the range of from about 20:1 to about 1:20.
In a
preferred embodiment of the present invention, the promoter component is a
bimetallic
promoter component comprising nickel and cobalt in a weight ratio of about
1:1.
In the manufacture of a sorbent composition of the present invention, the
support
component is generally prepared by combining the support component, generally
2S comprising zinc oxide and any inorganic or organic carrier, preferably
comprising zinc
oxide, silica and alumina, and the attrition-resistance-enhancing component
together in
appropriate proportions by any suitable method or manner which provides for
the intimate
mixing of such components to thereby provide a substantially homogeneous
mixture
comprising zinc oxide, any inorganic or organic carrier, and an attrition-
resistance-
enhancing component, preferably a substantially homogeneous mixture comprising
zinc
oxide, silica, alumina, and an attrition-resistance-enhancing component. Any
suitable
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means for mixing the support component, preferably comprising zinc oxide,
silica, and
alumina, and the attrition-resistance-enhancing component can be used to
achieve the
desired dispersion of such components. Examples of suitable means for mixing
include,
but are not limited to, mixing tumblers, stationary shells or troughs, Muller
mixers, which
are of the batch or continuous type, impact mixers, and the like. It is
presently preferred
to use a Muller mixer as the means for mixing the support component,
preferably
comprising zinc oxide, silica, alumina, and the attrition-resistance-enhancing
component.
The support component, generally comprising zinc oxide and any inorganic or
organic carrier, preferably comprising zinc oxide, silica and alumina, and the
attrition
resistance-enhancing component, preferably comprising a clay, are contacted
together by
any manner known in the art to provide a resulting mixture which can be in a
form
selected from the group consisting of a wet mix, a dough, a paste, a slurry
and the like.
Such resulting mixture can then be shaped to form a particulate(s) selected
from the group
consisting of a granulate, an extrudate, a tablet, a sphere, a pellet, a micro-
sphere, and the
1f like. For example, if the resulting mixture is in the form of a wet mix,
the wet mix can be
densified, dried under a drying condition as disclosed herein, calcined under
a calcining
condition as disclosed herein, and thereafter shaped, or particulated, through
the
granulation of the densified, dried, calcined mix to form granulates.. Also
for example,
when the resulting mixture of the support component, generally comprising zinc
oxide
and any inorganic or organic carrier, preferably comprising zinc oxide, silica
and alumina,
and the attrition-resistance-enhancing component, preferably comprising a
clay, is in the
form of either a dough state or paste state, such resulting mixture can then
be shaped,
preferably extruded, to form a particulate, preferably cylindrical extrudates
having a
diameter in the range of from about 1/32 inch to 1/2 inch and any suitable
length,
preferably a length in the range of from about 1/8 inch to about 1 inch. The
resulting
particulates, preferably cylindrical extrudates, are then dried under a drying
condition as
disclosed herein and then calcined under a calcining condition as disclosed
herein.
More preferably, the resulting mixture of the support component, preferably
comprising zinc oxide, silica and alumina, and the attrition-resistance-
enhancing
component, preferably comprising a clay, is in the form of a slurry and the
particulation of
such slurry is achieved by spray drying the slurry to form micro-spheres
thereof having a
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size generally in the range of from about 1 micrometer to about 1000
micrometers,
preferably in the range of from about 5 micrometers to about 500 micrometers.
Such
micro-spheres are then subjected to drying under a drying condition as
disclosed herein
and calcining under a calcining condition as disclosed herein. '
When the particulation is achieved by preferably spray drying, a dispersant
component can be utilized and can be any suitable compound that helps to
promote the
spray drying ability of the resulting mixture which is preferably in the form
of a slurry. In
particular, these dispersant components are useful in preventing deposition,
precipitation,
settling, agglomerating, adhering, and caking of solid particles in a fluid
medium.
Examples of suitable dispersant components include, but are not limited to,
condensed
phosphates, sulfonated polymers, ammonium polyacrylate, sodium polyacrylate,
ammonium polymethacrylate, sodium polymethacrylate, poly(methyl methacrylate),
poly(acrylic acid, sodium salt), polyacrylamide, and the like and combinations
thereof.
The term condensed phosphates refers to any dehydrated phosphate where the
HZO:P205
is less than about 3:1. Additional examples of suitable dispersant components
include,
but are not limited to, sodium pyrophosphate, sodium metaphosphate, sulfonated
styrene
malefic anhydride polymer, and the like and combinations thereof. The amount
of a
dispersant component used is generally in the range of from about 0.01 weight
percent
dispersant component based on the total weight of the components to about 10
weight
percent dispersant component. Preferably, the amount of a dispersant component
used is
generally in the range of from about 0.1 weight percent to about 8 weight
percent and,
more preferably, the amount of a dispersant component used is in the range of
from 1
weight percent to 5 weight percent.
In preparing a spray-dried sorbent composition of the present invention, an
acid
component can be used. In general, the acid component can be an organic acid
or a
mineral acid. If the acid component is an organic acid, it is preferred if it
is a carboxylic
acid. If the acid component is a mineral acid it is preferred if it is a
mineral acid selected
from the group consisting of nitric acid, phosphoric acid, hydrochloric acid,
sulfuric acid,
and the like and combinations thereof. Generally, the acid is used with water
to form a
dilute aqueous acid solution. The amount of acid in the acid component is
generally in
the range of from about 0.01 volume percent based on the total volume of the
acid
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component to about 20 volume percent. Preferably, the amount of acid is in the
range of
from about 0.1 volume percent to about 15 volume percent and, more preferably,
the
amount of acid is in the range of from 1 volume percent to 10 volume percent.
In general,
the amount of acid component to be used is based on the amount of the dry
components.
That is, the ratio of all the dry components (in grams) to the acid component
(in
milliliters) should be less than about 1.75:1. However, it is preferred if
this ratio is less
than about 1.25:1 and it is more preferred if it is less than about 1:1. These
ratios will
help to form a mixture that is a liquid solution, a slurry, or a paste that is
capable of being
dispersed in a fluid-like spray.
In preparing a preferred spray-dried sorbent composition of the present
invention,
a support component, comprising zinc oxide, silica, and alumina, a dispersant
component,
and an attrition-resistance-enhancing component comprising a clay can be
contacted
together in any maimer known in the art that will form a mixture that is a
liquid solution,
a slurry, or a paste that is capable of being dispersed in a fluid-like spray.
When a support
component, a dispersant component, and an attrition-resistance-enhancing
component are
solids, then they should be contacted in a liquid medium to form a mixture
that is a liquid
solution, a slurry, or a paste that is capable of being dispersed in a fluid-
like spray.
Suitable means for contacting these components are known in the art such as,
for
example, tumblers, stationary shells, troughs, muller mixers, impact mixers,
and the like.
Generally, these components, after contacting to form a mixture, are contacted
with an acid component as described herein. However, the dry components and
the acid
components) can be contacted together simultaneously or separately.
After the components are contacted together to form a mixture, they are
subjected
to spray drying to form a spray-dried sorbent material comprising
particulates, preferably
in the form of micro-spheres, that have a mean particle size in the ranges as
disclosed
herein. Spray drying is known in the art and is discussed in Perry's Chemical
Ehgiyaeers'
Hayadbook, Sixth Edition, published by McGraw-Hill, Inc., at pages 20-54
through 20-58.
Additional information can be obtained from the Handbook of Industrial Drying,
published by Marcel Dekker. Inc., at pages 243 through 293.
The spray-dried sorbent material can then be dried under a drying condition as
disclosed herein and then calcined, preferably in an oxidizing atmosphere such
as in the
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presence of oxygen or air, under a calcining condition as disclosed herein to
form a
calcined, spray-dried sorbent material. The calcination can be conducted under
any
suitable condition that removes residual water and oxidizes any combustibles.
Generally, the spray dried sorbent material has a mean particle size in the
range of
from about 1 micrometer to about 1000 micrometers, preferably in the range of
from
about 5 micrometers to about 500 micrometers and, more preferably, in the
range of from
micrometers to 200 micrometers.
The term "mean particle size" refers to the size of the particulate material
as
determined by using a RO-TAP Testing Sieve Shaker, manufactured by W.S. Tyler
Inc.,
10 of Mentor, Ohio, or other comparable sieves. The material to be measured is
placed in
the top of a nest of standard eight inch diameter stainless steel frame sieves
with a pan on
the bottom. The material undergoes sifting for a period of about 10 minutes;
thereafter,
the material retained on each sieve is weighed. The percent retained on each
sieve is
calculated by dividing the weight of the material retained on a particular
sieve by the
weight of the original sample. This information is used to compute the mean
particle
size.
The resulting particulated (preferably spray-dried), dried, and calcined
material
comprising a support component (generally comprising zinc oxide and any
inorganic or
organic Garner, preferably comprising zinc oxide, silica, and alumina) and an
attrition-
resistance-enhancing component (preferably comprising a clay) are then
incorporated with
a promoter component selected from the group consisting of metals, metal
oxides, and the
like and combinations thereof including compounds containing such metals and
metal
oxides, preferably a nickel oxide compound or a nickel oxide precursor or a
bimetallic
promoter component comprising a nickel oxide compound, or a nickel oxide
precursor,
and a cobalt oxide compound or a cobalt oxide precursor.
Following the incorporating of the particulated, dried, and calcined material,
comprising a support component and an attrition-resistance-enhancing
component, with a
promoter component, the resulting promoted particulates are then subjected to
drying
under a drying condition as disclosed herein and calcined under a calcining
condition as
disclosed herein to thereby provide dried, calcined, promoted particulates
prior to the
subjecting of such dried, calcined, promoted particulates to reduction with a
reducing
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agent, preferably hydxogen.
The promoter components) may be incorporated on, in, or with the particulated
(preferably spray-dried), dried, and calcined material comprising a support
component
and an attrition-resistance-enhancing component by any suitable means or
method for
incorporating the promoter components) on, in, or with, a substrate material,
such as the
dried and calcined particulates, which results in the formation of a promoted
sorbent
composition which can then be dried under a drying condition as disclosed
herein and
calcined under a calcining condition as disclosed herein to thereby provide
dried,
calcined, promoted particulates. The dried, calcined, promoted paxticulates
can then be
subjected to reduction with a reducing agent, preferably hydrogen, to thereby
provide a
sorbent composition of the present invention. Examples of means or methods for
incorporating a promoter components) include, but are not limited to,
impregnating,
soaking, spraying, and the like and combinations thereof.
A preferred method of incorporating is impregnating using any standard
incipient
wetness impregnation technique (i.e., essentially completely filling the pores
of a
substrate material with a solution of the incorporating elements) for
impregnating a
substrate, such as the preferred particulated, dried, and calcined material
(i.e.,
particulates) comprising a support component (preferably comprising zinc
oxide, silica
and alumina) and an attrition-resistance-enhancing component (preferably
comprising a
clay) prepared according to a process of the present invention, with a
promoter
component(s). A preferred method uses an impregnating solution comprising the
desirable concentration of a promoter components) so as to ultimately provide
a
promoted particulate(s) which can then be subjected to drying under a drying
condition as
disclosed herein and calcining under a calcining condition as disclosed herein
followed by
reduction with a reducing agent such as hydrogen to provide a sorbent
composition of the
present invention. The impregnating solution can be any aqueous solution and
amounts
of such solution which suitably provides for the impregnation of the
particulates
comprising a support component (preferably comprising zinc oxide, silica and
alumina)
and an attrition-resistance-enhancing component (preferably comprising a clay)
prepared
according to a process of the present invention to give an amount of promoter
component
that provides, after reduction with a reducing agent, a reduced promoter
component
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content sufficient to permit the removal of sulfur from a hydrocarbon-
containing fluid
such as cracked-gasoline or diesel fuel when such fluid is treated in
accordance with a
process of the present invention.
It can be desirable to use an impregnating solution comprising a promoter
component and an aqueous or nonaqueous solvent for the impregnation of the
particulates. A preferred impregnating solution comprises an aqueous solution
formed by
dissolving a metal-containing compound, preferably such metal-containing
compound is
in the form of a metal salt, such as, but not limited to, a metal chloride, a
metal nitrate, a
metal sulfate, and the like and combinations thereof, in an aqueous solvent
comprising
water. Examples of suitable aqueous and nonaqueous solvents include, but are
not
limited to, water, alcohols, esters, ethers, ketones, and the like and
combinations thereof.
Generally, the weight ratio of promoter component to the aqueous or nonaqueous
solvent of such impregnating solution can be in the range of from about 1:1 to
about 4:1,
preferably, in the range of from 1.5:1 to 3:1.
In preparing the spray-dried sorbent material, a promoter components) can be
added to the spray-dried sorbent material as a components) of the original
mixture, or
can be added after the original mixture has been spray dried, dried, and
calcined. If a
promoter components) is added to the spray-dried sorbent material after it has
been
spray-dried, dried, and calcined, the spray-dried sorbent material should be
dried again
under a drying condition as disclosed herein and then calcined again under a
calcining
condition as disclosed herein.
A preferred impregnating solution is formed by dissolving a metal-containing
compound (such as nickel nitrate hexahydrate) in water. It is acceptable to
use somewhat
of an acidic solution to aid in the dissolution of the metal-containing
compound. It is
more preferred for the particulates to be impregnated with a nickel component
by use of a
solution containing niclcel nitrate hexahydrate dissolved in water.
An example method of incorporating a promoter component on, in, or with a
material comprising a support component and an attrition-resistance-enhancing
component, preferably particulates comprising zinc oxide, silica, alumina, and
a clay,
prepared according to a process of the present invention, is to impregnate
such
particulates with a promoter component, initially in the form of a metal-
containing
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compound, which has been melted under a melting condition as described herein.
Preferably such promoter component is initially in the form of a metal-
containing
compound such as a metal salt, such as, but not limited to, a metal chloride,
a metal
nitrate, a metal sulfate, and the like and combinations thereof (such as, but
not limited to,
nickel nitrate hexahydrate). Addition of small amounts of an aqueous or
nonaqueous
solvent, such as water, to the promoter component can be used to assist in the
melting of
such promoter component, but such use of a solvent is not required.
Such melting condition includes a temperature in a range of from the melting
point of the promoter component to below the decomposition temperature of the
promoter
component for a time period and at a pressure that provides for a melted
promoter
component. The term "decomposition temperature" refers to the temperature at
which
the promoter component is no longer soluble and is no longer suitable for
incorporating,
preferably impregnating, the promoter component onto the material comprising a
support
component and an attrition-resistance-enhancing component according to a
process of the
present invention.
The temperature of such melting condition varies depending on the promoter
component but such temperature should be such as to provide a melted promoter
component. Such temperature is generally in the range of from about
75°F to about
700°F, preferably in the range of from about 85°F to about
300°F, more preferably in the
range of from about 95°F to about 280°F and, most preferably, in
the range of from 95°F
to 250°F.
Such melting condition can include a time period generally in the range of
from
about 1 minute to about 2 hours, preferably in the range of from about 5
minutes to about
1.5 hours and, most preferably, in the range of from 5 minutes to 1 hour. Such
melting
condition can include a pressure generally in the range of from about
atmospheric (i.e.,
about 14.7 pounds per square inch absolute) to about 150 pounds per square
inch absolute
(psia), preferably in the range of from about atmospheric to about 100 psia,
most
preferably about atmospheric, so long as the desired temperature can be
maintained.
The thus-melted promoter component is then used to incorporate, preferably
impregnate, such promoter component onto a material comprising a support
component
and an attrition-resistance-enhancing component, preferably particulates
comprising zinc
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oxide, silica, aluxnina, and a clay, prepared according to a process of the
present
invention. The melted promoter component is incorporated, preferably
impregnated, onto
the material comprising a support component and an attrition-resistance-
enhancing
component, preferably particulates comprising zinc oxide, silica, alumina, and
a clay,
prepared according to a process of the present invention, by any manner or
method which
results in substantially all the surface area of the particulates being
contacted with the
melted promoter component resulting in distribution of the promoter component.
The
phrase "substantially all the surface area of the particulates being contacted
with the
melted promoter component" generally refers to greater than twenty-five
percent of the
surface axea of the particulates, preferably greater than forty percent of the
surface area of
the particulates, more preferably greater than sixty percent of the surface
axea of the
particulates, and most preferably greater than ninety-five percent of the
surface area of the
particulates being contacted with the melted promoter component.
Another example method of incorporating, preferably impregnating, a melted
promoter component onto the material comprising a support component and an
attrition-
resistance-enhancing component, preferably particulates comprising zinc oxide,
silica,
alumina, and a clay, prepared according to a process of the present invention,
is by mixing
a solid promoter component (i.e., an unmelted promoter component) with the
particulates
by any manner or method which results in a mixture of particulates and solid
promoter
component. The mixture of particulates and solid promoter component is then
subj ected
to a melting condition as described herein, preferably while such mixture is
subjected to
constant stirring or tumbling, which results in substantially all the surface
area of the
particulates being contacted with a melted promoter component resulting in
distribution
of the promoter component.
Another example method of incorporating, preferably impregnating, a melted
promoter component onto the material comprising a support component and an
attrition-
resistance-enhancing component, preferably particulates comprising zinc oxide,
silica,
alumina, and a clay, prepared according to a process of the present invention,
is by pre-
heating the particulates under a heating condition as described herein to
thereby provide a
pre-heated support component (i.e., pre-heated particulates) followed by
contact with a
solid promoter component (i.e., an unmelted promoter component) which results
in a
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melting of the solid promoter component upon contact with the pre-heated
particulates
which further results in substantially all the surface area of the
particulates being
contacted with the melted promoter component. Preferably such pre-heated
particulates
are under constant stirring or tumbling during contact with the promoter
component.
Such mixture of particulates and melted promoter component can be further
heated near
the melting point of the promoter component for a time period in the range of
from about
0.5 hour to about 15 hours, preferably in the range of from about 1 hour to
about 8 hours
and, most preferably, in the range of from 1 hour to 5 hours to further aid in
the melting
of the promoter component.
Such heating condition, suitable for pre-heating the material comprising a
support
component and an attrition-resistance-enhancing component, preferably
particulates
comprising zinc oxide, silica, alumina, and a clay, prepared according to a
process of the
present invention, can include a temperature generally in the range of from
about 175°F to
about 300°F, preferably in the range of from about 185°F to
about 280°F and, more
preferably, in the range of from 190°F to 260°F. Such heating
condition can include a
time period generally in the range of from about 1 minute to about 2 hours,
preferably in
the range of from about 5 minutes to about 1.5 hours and, more preferably, in
the range of
from 5 minutes to 1 hour. Such heating condition can include a pressure
generally in the
range of from about atmospheric (i.e., about 14.7 pounds per square inch
absolute) to
about 150 pounds per square inch absolute (psia), preferably in the range of
from about
atmospheric to about 100 psia, more preferably about atmospheric, so long as
the desired
temperature can be maintained.
Another example method of incorporating, preferably impregnating, a melted
promoter component onto the material comprising a support component and an
attrition-
resistance-enhancing component, preferably particulates comprising zinc oxide,
silica,
alumina, and a clay, prepared according to a process of the present invention,
is by
subjecting a solid promoter component to a melting condition as described
herein to
thereby provide a melted promoter component which has become viscous enough to
pour.
The particulates are then contacted with such melted promoter component by
pouring
such melted promoter component onto the surface of the particulates by any
manner or
methods) which results in substantially all the surface area of the
particulates being
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contacted with the melted promoter component resulting in distribution of the
promoter
component. Preferably, such melted promoter component is poured onto the
surface of
the particulates while such particulates are under constant stirring or
tumbling. It can be
desirable to pre-heat the material comprising a support component and an
attrition-
resistance-enhancing component, preferably particulates comprising zinc oxide,
silica,
alumina, and a clay, prepared according to a process of the present invention,
under a
heating condition as described herein before contact with the melted promoter
component.
In another example method, solid nickel nitrate hexahydrate is used to
incorporate,
preferably impregnate, the nickel of such solid nickel nitrate hexahydrate
onto the
material comprising a support component and an attrition-resistance-enhancing
component, preferably particulates comprising zinc oxide, silica, alumina, and
a clay,
prepared according to a process of the present invention. The nickel of such
solid nickel
nitrate hexahydrate is incorporated, preferably impregnated, onto the
particulates by
mixing such solid nickel nitrate hexahydrate with the particulates by any
manner or
method which results in a mixture of solid nickel nitrate hexahydrate and
particulates and
then subjecting such mixture, while under constant stirring or tumbling, to a
melting
condition as described herein with results in substantially all the surface
area of the
particulates being contacted with melted nickel nitrate hexahydrate resulting
in
distribution of the nickel nitrate hexahydrate. In addition, cobalt nitrate
hexahydrate or .
iron nitrate nonahydrate or manganese nitrate hexahydrate or copper nitrate or
zinc nitrate
hexahydrate or silver nitrate or the like and combinations thereof can be used
in place of
nickel nitrate hexahydrate to incorporate, preferably impregnate, the metal of
such metal-
containing compounds) onto the particulates in the same above-described manner
as for
incorporating, preferably impregnating, the nickel of such nickel nitrate
hexahydrate.
Also preferred, solid nickel nitrate hexahydrate and solid cobalt nitrate
hexahydrate are
mixed with the particulates and then the resulting mixture, while under
constant stirring
or tumbling, is subjected to a melting condition as described herein to
incorporate,
preferably impregnate, the nickel and cobalt onto the particulates. After
drying and
calcining, a sorbent composition comprising a bimetallic promoter component
comprising
nickel and cobalt is formed.
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In another example method, the nickel of such solid nickel nitrate hexahydrate
is
incorporated, preferably impregnated, onto the material comprising a support
component
and an attrition-resistance-enhancing component, preferably particulates
comprising zinc
oxide, silica, alumina, and a clay, prepared according to a process of the
present
invention, by contacting such particulates, which have been pre-heated under a
heating
condition as described herein, with the solid nickel nitrate hexahydrate while
under
constant stirring or tumbling. Such contacting results in a melting of the
solidwickel
nitrate hexahydrate upon contact with the pre-heated particulates which
results in
substantially all the surface area of the pre-heated particulates being
contacted with
melted nickel nitrate hexahydrate resulting in distribution of the nickel
nitrate
hexahydrate. In addition, cobalt nitrate hexahydrate or iron nitrate
nonahydrate or
manganese nitrate hexahydrate or copper nitrate or zinc nitrate hexahydrate or
silver
nitrate or the lilce and combinations thereof can be used in place of nickel
nitrate
hexahydrate to incorporate, preferably impregnate, the metal of such metal-
containing
compounds) onto the pre-heated particulates in the same above-described manner
as for
incorporating, preferably impregnating, the nickel of such nickel nitrate
hexahydrate.
Also, solid nickel nitrate hexahydrate and solid cobalt nitrate hexahydrate
can be
contacted with the pre-heated particulates while under constant stirnng or
tumbling to
incorporate, preferably impregnate, the nickel and cobalt onto the
particulates. After
drying and calcining, a sorbent composition comprising a bimetallic promoter
component
comprising nickel and cobalt is formed.
In another example method, solid nickel nitrate hexahydrate is subjected to a
melting condition to thereby provide a melted nickel nitrate hexahydrate which
is viscous
enough to pour. The resulting melted nickel nitrate hexahydrate is then used
to
incorporate, preferably impregnate, the niclcel of such melted nickel nitrate
hexahydrate
onto the material comprising a support component and an attrition-resistance-
enhancing
component, preferably particulates comprising zinc oxide, silica, alumina, and
a clay,
prepared according to a process of the present invention, which have been pre-
heated
under a heating condition as described herein. The nickel of such melted
nickel nitrate
hexahydrate is incorporated, preferably impregnated, onto the pre-heated
particulates by
adding such melted nickel nitrate hexahydrate to the pre-heated particulates
by pouring
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such melted nickel nitrate hexahydrate onto the surface of the pre-heated
particulates by
any manner or method which results in substantially all the surface area of
the particulates
being contacted with the melted nickel nitrate hexahydrate resulting in
distribution of the
nickel nitrate hexahydrate. Preferably, such melted nickel nitrate hexahydrate
is poured
onto the surface of the pre-heated particulates while such particulates are
under constant
stirnng or tumbling. In addition, cobalt nitrate hexahydrate or iron nitrate
nonahydrate or
manganese nitrate hexahydrate or copper nitrate or zinc nitrate hexahydrate or
silver
nitrate or the lilce and combinations thereof can be used in place of nickel
nitrate
hexahydrate to incorporate, preferably impregnate, the metal of such metal-
containing
compounds) onto the pre-heated particulates in the same above-described manner
as for
incorporating, preferably impregnating, the nickel of such nickel nitrate
hexahydrate.
Also, melted nickel nitrate hexahydrate and melted cobalt nitrate hexahydrate
can be
poured onto the surface of the pre-heated particulates while such particulates
are under
constant stirring or tumbling. After drying and calcining, a sorbent
composition
comprising a bimetallic promoter component comprising nickel and cobalt is
formed.
Generally, the amount of a promoter components) incorporated, preferably
impregnated, onto, into, or with the material comprising a support component
and an
attrition-resistance-enhancing component, preferably particulates comprising
zinc oxide,
silica, alumina and a clay, prepared according to a process of the present
invention, is an
amount which provides, after the promoted particulate material has been dried
under a
drying condition as disclosed herein and calcined under a calcining condition
as disclosed
herein, a sorbent composition having an amount of promoter component as
disclosed
herein.
Generally, a drying condition, as referred to herein, can include a
temperature in
the range of from about 180°F to about 290°F, preferably in the
range of from about
190°F to about 280°F and, more preferably, in the range of from
200°F to 270°F. Such
drying condition can also include a time period generally in the range of from
about 0.5
hour to about 60 hours, preferably in the range of from about 1 hour to about
40 hours
and, more preferably, in the range of from 1.5 hours to 20 hours. Such drying
condition
can also include a pressure generally in the range of from about atmospheric
(i.e., about
14.7 pounds per square inch absolute) to about 150 pounds per square inch
absolute
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(psia), preferably in the range of from about atmospheric to about 100 psia,
more
preferably about atmospheric, so long as the desired temperature can be
maintained. Any
drying methods) known to one skilled in the art such as, for example, air
drying, heat
drying, vacuum drying, and the like and combinations thereof can be used.
Generally, a calcining condition, as referred to herein, can include a
temperature in
the range of from about 400°F to about 1800°F, preferably in the
range of from about
600°F to about 1600°F and, more preferably, in the range of from
800°F to about 1500°F.
Such calcining condition can also include a time period generally in the range
of from
about 1 hour to about 60 hours, preferably in the range of from about 2 hours
to about 20
hours and, more preferably, in the range of from 3 hours to 15 hours. Such
calcining
condition can also include a pressure, generally in the range of from about 7
pounds per
square inch absolute (psia) to about 750 psia, preferably in the range of from
about 7 psia
to about 450 psia and, more preferably, in the range of from 7 psia to 150
Asia.
Once a promoter component has been incorporated on, in, or with the material
comprising a support component and an attrition-resistance-enhancing
component,
preferably particulates comprising zinc oxide, silica, alumina, and a clay
(preferably
bentonite), the desired reduced-valence promoter component sorbent, preferably
reduced-
valence nickel sorbent, is prepared by drying the resulting composition under
a drying
condition as disclosed herein followed by calcining under a calcining
condition as
disclosed herein to thereby provide a dried, calcined, promoted
particulate(s). The dried,
calcined, promoted particulates are thereafter subjected to reduction with a
suitable
reducing agent, preferably hydrogen, to thereby provide a composition
comprising a
reduced-valence promoter component, preferably a zero-valence promoter
component,
with such zero-valence promoter component, preferably zero-valence nickel,
being
present in an amount sufficient to permit the removal of sulfur from a
hydrocarbon-
containing fluid such as cracked-gasoline or diesel fuel, according to a
process of the
present invention.
A sorbent composition of the present invention comprising a reduced-valence
promoter component is a composition that has the ability to react chemically
and/or
physically with sulfur. It is also preferable that the sorbent composition
removes diolefins
and other gum-forming compounds from cracked-gasoline.
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A sorbent composition of the present invention comprising a reduced-valence
promoter component comprises a promoter, component, preferably comprising
nickel, that
is in a substantially reduced valence state, preferably a zero valence state.
Preferably, the
reduced-valence promoter component is reduced nickel. The amount of reduced-
valence
promoter component, preferably reduced nickel, in a sorbent composition of the
present
invention is an amount which will permit the removal of sulfur from a
hydrocarbon-
containing fluid such as cracked-gasoline or diesel fuel. Such amount of
reduced-valence
promoter component, preferably reduced nickel, in a sorbent composition of the
present
invention is generally in the range of from about 5 to about 50 weight percent
of the total
weight of the sorbent composition. Preferably the reduced-valence promoter
component,
preferably reduced nickel, is present in an amount in the range of from about
8 to about
45 weight percent of the total weight of the sorbent composition and, more
preferably, in
an amount in the range of from.10 to 40 weight percent of the total weight of
the sorbent
composition.
In one presently preferred embodiment of a sorbent composition of the present
invention, the reduced nickel is present in an amount in the range of from 10
to 40 weight
percent reduced nickel based on the total weight of the sorbent composition
and the
reduced nickel has been substantially reduced to zero valence.
In another presently preferred embodiment of a sorbent composition of the
present
invention, zinc oxide is present in an amount in the range of from about 35 to
about 50
weight percent zinc oxide based on the total weight of the sorbent
composition, silica is
present in an amount in the range of from about 30 to about 40 weight percent
silica based
on the total weight of the sorbent composition, alumina is present in an
amount in the
range of from about 6 to about 12 weight percent alumina based on the total
weight of the
sorbent composition, bentonite is present in an amount in the range of from
about 2 to
about 12 weight percent bentonite based on the total weight of the sorbent
composition,
and nickel is present, prior to reduction to zero valence, in an amount in the
range of from
about 14 to about 30 weight percent nickel based on the total weight of the
sorbent
composition.
A sorbent composition of the present invention which is useful in a process of
the
present invention can be prepared by a process comprising:
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(a) contacting a support component, preferably comprising zinc oxide, silica,
and
alumina, and an attrition-resistance-enhancing component, preferably
comprising a clay,
so as to form a mixture selected from the group consisting of a wet mix, a
dough, a paste,
a slurry and the like and combinations thereof;
(b) particulating, preferably spray-drying, the mixture to form particulates
selected
from the group consisting of granulates, extrudates, tablets, pellets,
spheres, micro-
spheres, and the lilce and combinations thereof, preferably micro-spheres,
where such
particulates comprise such support component and such attrition-resistance-
enhancing
component;
(c) drying the particulate under a drying condition as disclosed herein to
form a
dried particulate;
(d) calcining the dried particulate under a calcining condition as disclosed
herein
to form a calcined particulate;
(e) incorporating, preferably impregnating, the calcined particulate with a
promoter component selected from the group consisting of metal, metal oxides,
and the
like and combinations thereof to form a promoted particulate;
( f ) drying the promoted particulate under a drying condition as disclosed
herein
to form a dried, promoted particulate;
(g) calcining the dried, promoted particulate under a calcining condition as
disclosed herein to form a calcined, promoted particulate; and
(h) reducing the calcined, promoted particulate with a suitable reducing agent
so
as to produce a sorbent composition having a reduced-valence promoter
component
content therein, preferably a reduced-valence nickel content therein, and
wherein the
reduced-valence promoter component content is present in an amount effective
for the
removal of sulfur from a hydrocarbon-containing fluid such as cracked-gasoline
or diesel
fuel when such hydrocarbon-containing fluid is contacted with a sorbent
composition of
the present invention according to a process of the present invention.
A process of using a novel sorbent compositions) of the present invention to
desulfurize a hydrocarbon-containing fluid comprising cracked-gasoline or
diesel fuel to
provide a desulfurized hydrocarbon-containing fluid comprising desulfurized
cracked-gasoline or desulfurized diesel fuel comprising:
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(a) desulfurizing, in a desulfurization zone, a hydrocarbon-containing fluid
with a
sorbent composition of the present invention to thereby provide a desulfurized
hydrocarbon-containing fluid and a resulting sulfurized sorbent composition;
(b) separating the desulfurized hydrocarbon-containing fluid and the resulting
sulfurized sorbent composition;
(c) regenerating, in a regeneration zone, at least a portion of the resulting
sulfurized sorbent composition to thereby provide a regenerated, desulfurized,
sorbent
composition;
(d) activating (i.e., reducing), in an activation zone, at least a portion of
the
regenerated, desulfurized, sorbent composition to thereby provide an activated
(i.e.,
reduced), regenerated, desulfurized sorbent composition; and
(e) returning at least a portion of the activated (i.e., reduced),
regenerated,
desulfurized sorbent composition to the desulfurization zone.
The desulfurizing of a hydrocarbon-containing fluid is carried out under a set
of
conditions that includes total pressure, temperature, weight hourly space
velocity, and
hydrogen flow. These conditions are such that the sorbent composition can
desulfuxize
the hydrocarbon-containing fluid to produce a desulfurized hydrocarbon-
containing fluid
and a sulfurized sorbent composition.
In carrying out the desulfurizing of a hydrocarbon-containing fluid, it is
preferred
that the hydrocarbon-containing fluid, preferably cracked-gasoline or diesel
fuel, be in a
gas or vapor phase. however, in the practice of the present invention it is
not essential
that the hydrocarbon-containing fluid be totally in a gas or vapor phase.
In carrying out the desulfurizing of a hydrocarbon-containing fluid, the total
pressure can be in the range of from about 15 pounds per square inch absolute
(psia) to
about 1500 psia. However, it is presently preferred that the total pressure be
in a range of
from about 50 psia to about 500 Asia. In general, the temperature should be
sufficient to
keep the hydrocarbon-containing fluid in essentially a vapor or gas phase.
While such
temperatures can be in the range of from about 100°F to about
1000°F, it is presently
preferred that the temperature be in the range of from about 400°F to
about 800°F when
treating a cracked-gasoline and in the range of from about 500°F to
about 900°F when
treating a diesel fuel.
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Weight hourly space velocity (WHSV) is defined as the numerical ratio of the
rate
at which a hydrocarbon-containing fluid is charged to the desulfurization zone
in pounds
per hour at standard condition of temperature and pressure (STP) divided by
the pounds
of sorbent composition contained in the desulfixrization zone to which the
hydrocarbon-
s containing fluid is charged. Iii the practice of the present invention, such
WHSV should
be in the range of from about 0.5 hr-' to about 50 hr-1, preferably in the
range of from
about 1 hr-1 to about 20 hr-'. The desulfurizing (i.e., desulfurization) of a
hydrocarbon-
containing fluid should be conducted for a time sufficient to effect the
removal of sulfur
from such hydrocarbon-containing fluid.
In carrying out the desulfurizing of a hydrocarbon-containing fluid, it is
presently
preferred that an agent be employed which interferes with any possible
chemical or
physical reacting of the olefmic and aromatic compounds in the hydrocarbon-
containing
fluid which is being treated with a sorbent composition of the present
invention.
Preferably, such agent is hydrogen.
Hydrogen flow in the desulfurization zone is generally such that the mole
ratio of
hydrogen to hydrocarbon-containing fluid is the range of from about 0.1 to
about 10,
preferably in the range of from about 0.2 to about 3.
The desulfurization zone can be any zone wherein desulfixrizing a hydrocarbon-
containing fluid such as cracked-gasoline, diesel fuel or the like can take
place. The
regeneration zone can be any zone wherein regenerating or desulfurizing a
sulfurized
sorbent composition can take place. The activation zone can be any zone
wherein
activating, i.e., reducing, a regenerated, desulfurized sorbent composition
can take place.
Examples of suitable zones are fixed bed reactors, moving bed reactors,
fluidized bed
reactors, transport reactors, reactor vessels and the like.
If desired, during the desulfin-izing of a hydrocarbon-containing fluid
according to
a process of the present invention, a diluent such as methane, carbon dioxide,
flue gas,
nitrogen and the like and combinations thereof can be used. Thus, it is not
essential to the
practice of a process of the present invention that a high purity hydrogen be
employed in
achieving the desired desulfizrization of a hydrocarbon-containing fluid such
as
cracked-gasoline or diesel fixel.
It is presently preferred, when utilizing a fluidized bed reactor system, that
a
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sorbent composition be used having a mean particle size, as described herein,
in the range
of from about 1 micrometer to about 1000 micrometers. Preferably, such sorbent
composition has a mean particle size in the range of from about 5 micrometers
to about
500 micrometers and, more preferably, in the range of from 10 micrometers to
200
micrometers. When a fixed bed reactor system is employed for the practice of a
process
of the present invention, the sorbent composition should generally have a
particulate size
in the range of from about 1132 inch to about %2 inch diameter, preferably in
the range of
from about 1132 inch to about 1/4 inch diameter.
It is further presently preferred to use a sorbent composition having a
surface area
in the range of from about 1 square meter per gram to about 1000 square meters
per gram
(m2/g), preferably in the range of from about 1 m2/g to about 800 m2/g.
The separating of the desulfixrized hydrocarbon-containing fluid, preferably
gaseous or vaporized desulfurized hydrocarbon-containing fluid, and sulfurized
sorbent
composition can be accomplished by any manner or method known in the art that
can
separate a solid from a gas. Examples of suitable separating means for
separating solids
and gases include, but are not limited to, cyclonic devices, settling
chambers,
impingement devices, filters, and the like and combinations thereof. The
desulfurized
hydrocarbon-containing fluid, preferably desulfurized gaseous cracked-gasoline
or
desulfurized gaseous diesel fuel, can then be recovered and preferably
liquefied.
Liquification of such desulfurized hydrocarbon-containing fluid can be
accomplished by
any manner or method known in the art.
The hydrocarbon-containing fluid as described herein, preferably gaseous
cracked-gasoline or gaseous diesel fuel, suitable as a feed in a process of
the present
invention is a composition that comprises olefins, aromatics, sulfur, as well
as paraffins
and naphthenes.
The amount of olefins in gaseous cracked-gasoline is generally in the range of
from about 10 to about 35 weight percent olefins based on the total weight of
the gaseous
cracked-gasoline. For diesel fuel there is essentially no olefin content.
The amount of aromatics in gaseous cracked-gasoline is generally in the range
of
from about 20 to about 40 weight percent aromatics based on the total weight
of the
gaseous cracked-gasoline. The amount of aromatics in gaseous diesel fuel is
generally in
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the range of from about 10 to about 90 weight percent aromatics based on the
total weight
of the gaseous diesel fuel.
The amount of sulfur in the hydrocarbon-containing fluid, preferably
cracked-gasoline or diesel fuel, suitable for use in a process of the present
invention can
be in the range of from about 100 parts per million sulfur by weight of the
cracked-gasoline to about 10,000 parts per million sulfur by weight of the
cracked-gasoline and from about 100 parts per million sulfur by weight of the
diesel fuel
to about 50,000 parts per million sulfur by weight of the diesel fuel prior to
the treatment
of such hydrocarbon-containing fluid with a process of the present invention.
The amount of sulfur in the desulfurized hydrocarbon-containing fluid, such as
desulfurized cracked-gasoline or desulfurized diesel fuel, following treatment
in
accordance with a process of the present invention is less than about 100
parts per million
(ppm) sulfux by weight of hydrocarbon-containing fluid, preferably less than
about 90
ppm sulfur by weight of hydrocarbon-containing fluid, and more preferably less
than
about 80 ppm sulfur by weight of hydrocarbon-containing fluid.
In carrying out a process of the present invention, if desired, a stripper
zone can be
inserted before and/or after the regenerating of the sulfurized sorbent
composition. Such
stripper zone, preferably utilizing a stripping agent, will serve to remove a
portion,
preferably all, of any hydrocarbons) from the sulfurized sorbent composition.
Such
stripper zone can also serve to remove oxygen and sulfur dioxide from the
system prior to
introduction of the regenerated sorbent composition into the activation zone.
Such
stripping employs a set of conditions that includes total pressure,
temperature, and
stripping agent partial pressure.
Preferably, the stripping, when employed, is carried out at a total pressure
in the
range of from about 25 pounds per square inch absolute (psia) to about 500
Asia. The
temperature for such stripping can be in the range of from about 100°F
to about 1000°F.
Such stripping is carried out for a time sufficient to achieve the desired
level of stripping.
Such stripping can generally be achieved in a time period in the range of from
about 0.1
hour to about 4 hours, preferably in the range of from about 0.3 hour to about
1 hour.
The stripping agent is a compositions) that helps to remove a hydrocarbons)
from the sulfurized sorbent composition. Preferably, the stripping agent is
nitrogen.
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The regenerating is carned out under a set of conditions that includes total
pressure and sulfur removing agent partial pressure. Total pressure is
generally in the
range of from about 25 pounds per square inch absolute (psia) to about 500
psia.
The sulfur removing agent partial pressure is generally in the range of from
about
1 percent to about 100 percent of the total pressure.
The sulfur removing agent, i.e., regenerating agent, is a compositions) that
helps
to generate gaseous sulfur-containing compounds and oxygen-containing
compounds
such as sulfur dioxide, as well as to burn off any remaining hydrocarbon
deposits that
might be present. The preferred sulfur removing agent, i.e., regenerating
agent, suitable
for use in the regeneration zone is oxygen or an oxygen-containing gases) such
as air.
Such regeneration is carried out for a time sufficient to achieve the desired
level of
regeneration. Such regeneration can generally be achieved in a time period in
the range of
from about 0.1 hour to about 24 hours, preferably in the range of from about
0.5 hour to
about 3 hours.
The regenerating is carried out at a temperature generally in the range of
from
about Z 00°F to about 1500°F, preferably in the range of from
about 800°F to about
1200°F.
The desulfurized sorbent composition is then subjected to activating, i.e.,
reducing, in an activation zone with a reducing agent, preferably hydrogen, so
that at least
a portion of the promoter component, preferably comprising nickel,
incorporated on, in,
or with the sorbent composition is reduced to thereby provide a sorbent
composition
comprising a reduced-valence promoter component, preferably reduced nickel.
Such
sorbent composition comprises a reduced-valence promoter component, preferably
reduced nickel, incorporated on, in, or with such sorbent composition in an
amount that
provides for the removal of sulfur from a hydrocarbon-containing fluid such as
cracked-gasoline or diesel fuel according to a process of the present
invention.
In general, when practicing a process of the present invention, the
activating, i.e.,
reducing, of the regenerated, desulfurized sorbent composition is carried out
at a
temperature in the range of from about 100°F to about 1500°F and
at a pressure in the
range of from about 15 pounds per square inch absolute (psia) to about 1500
psia. Such
reduction is carned out for a time sufficient to achieve the desired level of
promoter
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component reduction. Such reduction can generally be achieved in a time period
in the
range of from about 0.01 hour to about 20 hours.
Following the activating, i.e., reducing, of the regenerated, desulfurized
sorbent
composition, at least a portion of the resulting activated (i.e., reduced)
sorbent
composition can be returned to the desulfurization zone.
When carrying out a process of the present invention, the steps of
desulfurizing,
regenerating, activating (i.e., reducing), and optionally stripping before
and/or after such
regenerating, can be accomplished in a single zone or vessel or in multiple
zones or
vessels.
When carrying out a process of the present invention in a fixed bed reactor
system,
the steps of desulfurizing, regenerating, activating, and optionally stripping
before and/or
after such regenerating are accomplished in a single zone or vessel.
When carrying out a process of the present invention in a fluidized bed
reactor
system, the steps of desulfurizing, regenerating, activating, and optionally
stripping before
and/or after such regenerating are accomplished in multiple zones or vessels.
When a desulfurized hydrocarbon-containing fluid resulting from the practice
of a
process of the present invention is a desulfurized cracked-gasoline, such
desulfurized
cracked-gasoline can be used in the formulation of gasoline blends to provide
gasoline
products suitable for commercial consumption and can also be used where a
cxacked-
gasoline containing low levels of sulfur is desired.
When a desulfurized hydrocarbon-containing fluid resulting from the practice
of a
process of the present invention is a desulfurized diesel fuel, such
desulfurized diesel fuel
can be used in the formulation of diesel fuel blends to provide diesel fuel
products
suitable for commercial consumption and can also be used where a diesel fuel
containing
low levels of sulfur is desired.
The following examples are presented to further
illustrate this invention and are not to be construed as unduly limiting the
scope of this
invention.
EXAMPLE I
Sorbent A (Control) was a spray-dried sorbent material prepared in the
following
manner. A 20 gram quantity of sodium pyrophosphate was dissolved in 2224 grams
of
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distilled water to provide a solution. To the solution was added 200 grams of
Vista
DISPAL 180 alumina with vigorous stirring. While the alumina slurry was being
mixed
with a high shear mixer, a 628 gram quantity of Celite Filter Cel (Celite
Corporation,
Lompoc, California) and a 788 gram quantity of zinc oxide were added to the
slurry and
further mixed for about 15 minutes. The resulting mixed slurry was sieved
through. a 25
mesh screen. The resulting sieved slurry was then spray-dried using a Niro
Mobile Minor
spray dryer equipped with a fountain head (Niro, Inc., Columbia, Maryland).
The
operating conditions of the spray dryer included an inlet temperature of
320°C and an
outlet temperature of about 100°C to about 120°C. The spray-
dried material was then
dried in an oven at 150°C for three hours and then calcined at
635°C for one hour to
thereby obtain a dried and calcined spray-dried sorbent material.
A 100 gram quantity of the thus dried and calcined spray-dried sorbent
material
(149 micron to 74 micron fraction) was then spray impregnated with a solution
of 59.4
grams of nickel nitrate hexahydrate (Ni(N03)z~6Hz0) in 62.9 grams of distilled
water.
The thus-impregnated material was then dried in an oven which was increased
from an
ambient temperature at 3°C per minute to 150°C and maintained at
150°C for three hours
and then increased at a rate of 3°C per minute to 635°C and
maintained at 635°C for one
hour to thereby obtain a nickel-impregnated spray-dried sorbent material.
A 50 gram quantity of the thus dried and calcined nickel-impregnated spray-
dried
sorbent material was then spray impregnated with a solution of 37.1 grams of
nickel
nitrate hexahydrate (Ni(N03)z~6Hz0) in 7.5 grams of distilled water. The
thus-impregnated material was then dried in an oven which was increased from
an
ambient temperature at 3°C per minute to 150°C and maintained at
150°C for three hours
and then increased at a rate of 3°C per minute to 635°C and
maintained at 635°C for one
hour to thereby obtain a twice-nickel-impregnated spray-dried sorbent material
(Control
Sorbent A). Control Sorbent A contained a final total of about 21 weight
percent nickel
based on the total weight of the material. The physical and chemical
characteristics of
Control Sorbent A are included in Table I. The Davison Index, as described
herein, was
determined using a 5 gram quantity of -100 to +200 mesh fraction of Control
Sorbent A.
Sorbent B (Invention) was a spray-dried sorbent material prepared in the
following
manner. A 20 gram quantity of sodium pyrophosphate was dissolved in 3000 grams
of
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distilled water to provide a solution. To the solution was added 200 grams of
Vista
DISPAL 180 alumina with vigorous stirring. While the alumina slurry was being
mixed
using a high shear mixer, a 314 gram quantity of Celite Filter Cel (Celite
Corporation,
Lompoc, California) and a 788 gram quantity of zinc oxide were added to the
slurry and
further mixed for about 20 minutes. A 187.2 gram quantity of bentonite 325 and
an
additional 1000 gram quantity of distilled water were then added to the
slurry. The
resulting mixed slurry was sieved through a 25 mesh screen. The resulting
sieved
material was then spray-dried using a Niro Mobile Minor spray dryer equipped
with a
fountain head (Niro, Inc., Columbia, Maryland). The operating conditions of
the spray
dryer included an inlet temperature of 320°C and an outlet temperature
of about 100°C to
about 120°C. The spray-dried material was then dried in an oven at
150°C and then
calcined at 635°C for one hour to thereby obtain a dried and calcined
spray-dried sorbent
material.
A 100 gram quantity of the thus dried and calcined spray-dried sorbent
material
(149 micron to 74 micron fraction) was then spray impregnated with a solution
of 59.4
grams of nickel nitrate hexahydrate (Ni(NQ3)2~6H20) in 20.4 grams of distilled
water.
The thus-impregnated material was then dried in an oven which was increased
from an
ambient temperature at 3°C per minute to 150°C and maintained at
150°C for one hour
and then increased at a rate of 3°C per minute to 635°C and
maintained at 635°C for one
hour to thereby obtain a nickel-impregnated spray-dried sorbent material.
A 50 gram quantity of the thus dried and calcined nickel-impregnated spray-
dried
sorbent material was then spray impregnated with a solution of 22.3 grams of
nickel
nitrate hexahydrate (Ni(N03)2~6Hz0) in 13 grams of distilled water. The
resulting twice-
niclcel-impregnated spray-dried material was then dried in an oven which was
increased
from an ambient temperature at 3°C per minute to 150°C and
maintained at 150°C for one
hour and then increased at a rate of 3°C per minute to 635°C and
maintained at 635°C for
one hour to thereby obtain a twice-nickel-impregnated spray-dried sorbent
material.
A 54.4 gram quantity of such twice-nickel-impregnated spray-dried sorbent
material was then spray impregnated with a solution of 24.2 grams of nickel
nitrate
hexahydrate (Ni(N03)2~6Hz0) in 12.2 grams of distilled water. The resulting
material
was then dried in an oven which was increased from an ambient temperature at
3°C per
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minute to 150°C and maintained at 150°C for one hour and then
increased at a rate of 3°C
per minute to 635°C and maintained at 635°C for one hour to
thereby obtain a thrice-
nickel-impregnated spray-dried sorbent material (Invention Sorbent B).
Invention
Sorbent B contained a final total of about 23 weight percentwickel based on
the total
weight of the material and about 10 weight percent bentonite based on the
total weight of
the material.
The physical and chemical characteristics of Invention Sorbent B are included
in
Table I. The Davison Index, as described herein, was determined using a 5 gram
quantity
of -100 to +200 mesh fraction of Invention Sorbent B.
TABLE I
Particle Size DistributionControl Sorbent A Invention Sorbent B
(%) (No Attrition-Resistance-(With Attrition-Resistance-
Enhancing Component)Enhancing Component)
>297 microns 1.0 14.5
149 microns 57.8 25.8
IOS microns 39.9 19.7
88 microns 1.2 13.0
74 microns 0.1 . 22.0
53 microns 0 3.1
<53 microns 0 2.9
Davison Index 19 9
EXAMPLE II
This example illustrates the performance of Control Sorbent A and Invention
Sorbent B described herein in Example I in a desulfurization process.
Ten grams of Control Sorbent A were placed on a frit in a 1-inch diameter
quartz
reactor tube having a length of about 12 inches.
During each cycle, gaseous cracked-gasoline was pumped upwardly through the
reactor at a rate of 13.4 milliliters per hour (mL/HR). The gaseous cracked-
gasoline had a
motor octane number (MOIL of 80, an olefin content of 24.9 weight percent, 340
parts
per million sulfur by weight sulfur-containing compounds.based on the total
weight of the
gaseous cracked-gasoline, and about 95 weight percent thiophenic compounds
(such as,
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for example, alkyl benzothiophenes, alkyl thiophenes, benzothiophenes and
thiophenes)
based on the weight of sulfur-containing compounds in the gaseous cracked-
gasoline.
During each cycle, the reactor was maintained at a temperature of 700°F
and at a
pressure of 15 pounds per square inch absolute (psia). Hydrogen flow was at
150
standard cubic centimeters per minute (sccm) diluted with 150 sccm of
nitrogen.
Before Cycle 1 was initiated, Control Sorbent A was reduced with hydrogen
flowing at a rate of 300 sccm at a temperature of 700°F for a period of
one hour. Each
cycle consisted of four hours with the product sulfur (ppm) for each cycle
being measured
at one hour intervals over each four-hour cycle period. After each cycle,
Control Sorbent
A was regenerated at 900°F for 1.5 hours with a mixture of oxygen and
nitrogen
containing four volume percent oxygen, then purged with nitrogen, and then
reduced in
hydrogen flowing at a rate of 300 sccm for one hour at 700°F. Control
Sorbent A was
tested over two cycles.
The above-described testing procedure was then repeated in the same manner
with
the exception that Invention Sorbent B was used in place of Control Sorbent A
and was
tested over eight cycles.
The results of the test for Control Sorbent A axe shown below in Table II. The
results of the test for Invention Sorbent B are shown below in Table III.
TABLE II
Control Sorbent
A (No Attrition-Resistance-Enhancing
Component)
Cycle 1 Cycle 2
TOS' SULFUR (ppm)
IN THE PRODUCT
1 hr 10 5
2 hr 20 20
3 hr 25 15
4 hr 20 15
' TOS denotes Time on Stream in hours
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TABLE
III
Invention
Sorbent
B
(With
Attrition-Resistance-Enhancing
Component)
Cycle Cycle Cycle Cycle Cycle Cycle Cycle Cycle
1 2 3 4 S 6 7 8
TOS' *********SULFUR
(ppm)
IN
THE
PRODUCT
***************
1 1 S 10 <S 10 S 40 10 <S
hr
2 1S 1S 1S 2S 20 4S 30 S
hr
3 1p 10 1S 2S 1S 3S 40 10
hr
4 - Z 10 10 1S 10 20 30 S
hr
' TOS denotes Time on Stream in hours
Z Not Determined
The test data clearly demonstrate that use of a sorbent composition of the
present
invention to remove sulfur from cracked-gasoline containing 340 parts per
million sulfur
by weight sulfur-containing compounds based on the total weight of the cracked-
gasoline
1 S results in a significant reduction of the sulfur content of such cracked-
gasoline, generally
to a level of about S to 4S parts per million sulfur.
The test data further demonstrate that a sorbent composition which contained
about 10 weight percent of an attrition-resistance-enhancing component
(bentonite)
distributed throughout a sorbent composition prepared according to a process
of the
present invention desulfurized the cracked-gasoline as effectively as Control
Sorbent A,
while Invention Sorbent B exhibited superior attrition resistance.
The data also clearly show that Invention Sorbent B which contained an
attrition-
resistance-enhancing component (bentonite), exhibited a very high
effectiveness to
remove sulfur which was comparable to Control Sorbent A which did not contain
an
2S attrition-resistance-enhancing component, yet Invention Sorbent B exhibited
superior
attrition resistance properties. Invention Sorbent B exhibited excellent
sulfur removal
performance and little or no loss in sulfur removal efficiency during the 8
cycles of
operation conducted in Example II. The improvement in sorbent attrition
resistance is
believed to be due to a novel process of making the inventive sorbent
composition by a
process of utilizing an attrition-resistance-enhancing component and a support
component
to provide a material which is subsequently promoted with a promoter component
and
then reduced to produce a sorbent composition with enhanced attrition
resistance
CA 02420338 2003-02-21
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-39-
compared to a sorbent composition which does not contain such attrition-
resistance-
enhancing component.
The difference in performance between Invention Sorbent B and Control Sorbent
A is certainly unexpected. pne would not expect that contacting a support
component
and an attrition-resistance-enhancing component followed by promoting with a
promoter
component and then reducing to produce a sorbent composition would enhance the
performance of such sorbent composition in terms of attrition resistance, yet,
at a
desulfurization effectiveness comparable to a sorbent which does not contain
such
attrition-resistance-enhancing component. The results demonstrate that the
inventive
sorbent composition, containing an attrition-resistance-enhancing component,
is
significantly superior to a sorbent which does not contain such attrition-
resistance-
enhancing component.
The data also clearly show that Invention Sorbent B was highly effective in
sulfur
removal. Even after 8 cycles of operation, the amount of sulfur removed was
very high.
The results shown in the above examples clearly demonstrate that the present
invention is well adapted to carry out the objects and attain the ends and
advantages
mentioned as well as those inherent therein.
Reasonable variations, modifications, and adaptations can be made within the
scope of this disclosure and the appended claims without departing from the
scope of this
invention.
