U.S. patent application number 10/864202 was filed with the patent office on 2004-11-11 for desulfurization and novel sorbent for same.
Invention is credited to Khare, Gyanesh P..
Application Number | 20040222133 10/864202 |
Document ID | / |
Family ID | 25523845 |
Filed Date | 2004-11-11 |
United States Patent
Application |
20040222133 |
Kind Code |
A1 |
Khare, Gyanesh P. |
November 11, 2004 |
Desulfurization and novel sorbent for same
Abstract
A sorbent composition comprising a support and a reduced-valence
noble metal can be used to desulfurize a hydrocarbon-containing
fluid such as cracked-gasoline or diesel fuel.
Inventors: |
Khare, Gyanesh P.;
(Kingwood, TX) |
Correspondence
Address: |
Richmond, Hitchcock, Fish & Dollar
P.O. Box 2443
Bartlesville
OK
74005
US
|
Family ID: |
25523845 |
Appl. No.: |
10/864202 |
Filed: |
June 9, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10864202 |
Jun 9, 2004 |
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09976195 |
Oct 12, 2001 |
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Current U.S.
Class: |
208/213 ;
502/400 |
Current CPC
Class: |
C10G 2400/04 20130101;
B01J 20/3483 20130101; B01J 20/08 20130101; B01J 20/106 20130101;
B01J 2220/42 20130101; B01J 20/18 20130101; B01J 20/28019 20130101;
B01J 20/28004 20130101; B01J 20/28016 20130101; B01J 20/3458
20130101; B01J 20/02 20130101; B01J 20/06 20130101; B01J 20/3078
20130101; B01J 20/3433 20130101; B01J 20/3236 20130101; B01J 20/14
20130101; Y10S 502/514 20130101; B01J 20/3491 20130101; B01J 23/60
20130101; B01J 20/3204 20130101; B01J 20/103 20130101 |
Class at
Publication: |
208/213 ;
502/400 |
International
Class: |
C10G 025/00 |
Claims
1. A sorbent composition suitable for removing sulfur from a
hydrocarbon-containing fluid, said sorbent composition comprising:
a reduced-valence noble metal; zinc oxide; and a carrier.
2. A sorbent composition in accordance with claim 1 wherein said
reduced-valence noble metal has a valence which is less than the
valence of the metal of the reduced-valence noble metal in its
common oxidized state.
3. A sorbent composition in accordance with claim 2 wherein said
reduced-valence noble metal is present in the range of from about
0.01 to about 25 weight percent.
4. A sorbent composition in accordance with claim 3 wherein said
zinc oxide is present in the range of from about 10 to about 90
weight percent.
5. A sorbent composition in accordance with claim 4 wherein said
carrier comprises an inorganic carrier.
6. A sorbent composition in accordance with claim 5 wherein said
inorganic carrier is selected from the group consisting of 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 combinations of two or
more thereof.
7. A sorbent composition in accordance with claim 6 wherein said
inorganic carrier comprises a silica compound and an alumina
compound.
8. A sorbent composition in accordance with claim 7 wherein said
silica compound is present in an amount in the range of from about
5 to about 85 weight percent and wherein said alumina compound is
present in an amount in the range of from about 1 to about 30
weight percent.
9. A sorbent composition in accordance with claim 8 wherein said
reduced-valence noble metal is selected from the group consisting
of platinum, palladium, rhodium, ruthenium, osminium, iridium, and
combinations thereof.
10. A sorbent composition in accordance with claim 1 wherein said
reduced-valence noble metal has a valence of less than 2.
11. A sorbent composition in accordance with claim 10 wherein said
reduced-valence noble metal is present in an amount in the range of
from about 0.1 to about 10 weight percent and wherein said zinc
oxide is present in an amount in the range of from about 15 to
about 80 weight percent.
12. A sorbent composition in accordance with claim 11 wherein said
carrier comprises a silica compound and an alumina compound.
13. A sorbent composition in accordance with claim 12 wherein said
alumina compound is present in an amount in the range of from about
5 to about 20 weight percent and wherein said silica compound is
present in an amount in the range of from about 10 percent to about
60 weight percent.
14. A sorbent composition in accordance with claim 1 wherein said
reduced-valence noble metal has a valence of zero.
15. A sorbent composition in accordance with claim 14 wherein said
reduced-valence noble metal comprises platinum.
16. A sorbent composition in accordance with claim 1 wherein said
sorbent composition is a particulate in the form of a microsphere
having a mean particle size in the range of from about 1 micrometer
to about 500 micrometers.
17. Canceled.
18. Canceled.
19. Canceled.
20. Canceled.
21. Canceled.
22. Canceled.
23. Canceled.
24. Canceled.
25. Canceled.
26. Canceled.
27. Canceled.
28. Canceled.
29. Canceled.
30. Canceled.
31. Canceled.
32. Canceled.
33. Canceled.
34. A process for removing sulfur from a hydrocarbon-containing
fluid stream, said process comprising the steps of: (a) contacting
said hydrocarbon-containing fluid stream with a sorbent composition
comprising a reduced-valence noble metal and a support in a
desulfurization zone under conditions such that there is formed a
desulfurized fluid stream and a sulfurized sorbent; (b) separating
said desulfurized fluid stream from said sulfurized sorbent; (c)
regenerating at least a portion of the separated sulfurized sorbent
in a regeneration zone so as to remove at least a portion of the
sulfur therefrom and provide a desulfurized sorbent; (d) reducing
said desulfurized sorbent in an activation zone to provide a
reduced sorbent composition which will affect the removal of sulfur
from said hydrocarbon-containing fluid stream when contacted with
the same; and (e) returning at least a portion of said reduced
sorbent composition to said desulfurization zone.
35. A process in accordance with claim 34 wherein said support
comprises zinc oxide, alumina, and silica.
36. A process in accordance with claim 35 wherein said sorbent
composition comprises said reduced-valence noble metal in an amount
in the range of from about 0.01 to about 25 weight percent, said
zinc oxide in an amount in the range of from about 10 to about 90
weight percent, said alumina in an amount in the range of from
about 1 to about 30 weight percent, and said silica in an amount in
the range of from about 5 to about 85 weight percent.
37. A process in accordance with claim 36 wherein said
reduced-valence noble metal component comprises platinum.
38. A process in accordance with claim 34 wherein said contacting
is carried out at a temperature in the range of from about
100.degree. F. to about 1000.degree. F. and a pressure in the range
of from about 15 to about 1500 psia.
39. A process in accordance with claim 34 wherein said regeneration
is carried out at a temperature in the range of from about
100.degree. F. to about 1500.degree. F. and a pressure in the range
of from about 25 to about 500 psia.
40. A process in accordance with claim 39 wherein there is employed
air as a regeneration agent in said regeneration zone.
41. A process in accordance with claim 34 wherein said desulfurized
sorbent is subjected to reduction with hydrogen in said activation
zone, said activation zone being maintained at a temperature in the
range of from about 100.degree. F. to about 1500.degree. F. and a
pressure in the range of from about 15 to about 1500 psia.
42. A process in accordance with claim 34 wherein the separated
sulfurized sorbent is stripped prior to introduction to said
regeneration zone.
43. A process in accordance with claim 34 wherein said desulfurized
sorbent is stripped prior to introduction into said activation
zone.
44. A process in accordance with claim 34 wherein said
reduced-valence noble metal has a valence of less than 2.
45. A process in accordance with claim 34 wherein said
reduced-valence noble metal has a valence of zero.
46. A process in accordance with claim 45 wherein said
reduced-valence noble metal compound comprises platinum.
47. A process in accordance with claim 34 wherein said
hydrocarbon-containing fluid stream is cracked-gasoline.
48. A process in accordance with claim 34 wherein said
hydrocarbon-containing fluid stream is diesel.
49. The product produced by the process of claim 47.
50. The product produced by the process of claim 48.
51. A sorbent composition suitable for removing sulfur from a
hydrocarbon-containing fluid, said sorbent composition comprising:
a reduced-valence noble metal; zinc oxide; and a carrier; wherein
said reduced-valence noble metal is present in the range of from
about 1.01 to about 25 weight percent.
Description
RELATED APPLICATIONS
[0001] This is a continuation of application Ser. No. 09/976,195,
filed Oct. 12, 2001 entitled DESULFURIZATION AND NOVEL SORBENT FOR
SAME, and hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a sorbent composition, a process
of making a sorbent composition, and a process of using a sorbent
composition for the removal of sulfur from a hydrocarbon-containing
fluid.
[0003] Hydrocarbon-containing fluids such as gasoline and diesel
fuels typically contain a quantity of sulfur. High levels of sulfur
in such automotive fuels is undesirable because oxides of sulfur
present in automotive exhaust may irreversibly poison noble metal
catalysts employed in automobile catalytic converters. Emissions
from such poisoned catalytic converters may contain high levels of
non-combusted hydrocarbons, oxides of nitrogen, and/or carbon
monoxide, which, when catalyzed by sunlight, form ground level
ozone, more commonly referred to as smog.
[0004] Much of the sulfur present in the final blend of most
gasolines originates from a gasoline blending component commonly
known as "cracked-gasoline." Thus, reduction of sulfur levels in
cracked-gasoline will inherently serve to reduce sulfur levels in
most gasolines, such as, automobile gasolines, racing gasolines,
aviation gasolines, boat gasolines, and the like.
[0005] Many conventional processes exist for removing sulfur from
cracked-gasoline. However, most conventional sulfur removal
processes, such as hydrodesulfurization, tend to saturate olefins
and aromatics in the cracked-gasoline and thereby reduce its octane
number (both research and motor octane number). Thus, there is a
need for a process wherein desulfurization of cracked-gasoline is
achieved while the octane number is maintained.
[0006] In addition to the need for removing sulfur from
cracked-gasoline, there is also a need to reduce the sulfur content
in 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
hydrodesulfurization and aromatic hydrogenation reactions. Thus,
there is a need for a process wherein desulfurization is achieved
without a significant consumption of hydrogen so as to provide a
more economical process for the desulfurization of
hydrocarbon-containing fluids.
SUMMARY OF THE INVENTION
[0007] It is thus an object of the present invention to provide a
novel sorbent system for the removal of sulfur from
hydrocarbon-containing fluid streams such as cracked-gasoline and
diesel fuels.
[0008] Another object of this invention is to provide a method of
making a novel sorbent which is useful in the desulfurization of
such hydrocarbon-containing fluid streams.
[0009] Still another object of this invention is to provide a
process for the removal of sulfur-containing compounds from
hydrocarbon-containing fluid streams which minimizes saturation of
olefins and aromatics therein.
[0010] A further object of this invention is to provide a process
for the removal of sulfur-containing compounds from
hydrocarbon-containing fluid streams which minimizes hydrogen
consumption.
[0011] It should be noted that the above-listed objects need not
all be accomplished by the invention claimed herein and other
objects and advantages of this invention will be apparent from the
following description of the invention and appended claims.
[0012] In one aspect of the present invention, there is provided a
novel sorbent composition suitable for removing sulfur from a
hydrocarbon-containing fluid. The sorbent composition comprises a
reduced-valence noble metal, zinc oxide, and a carrier.
[0013] In accordance with another aspect of the present invention,
there is provided a process of making a sorbent composition. The
process comprises the steps of: admixing zinc oxide and a carrier
so as to form a support mix; particulating the support mix so as to
form a support particulate; incorporating the support particulate
with a noble metal or a noble metal-containing compound to provide
a promoted particulate comprising an unreduced noble metal; and
reducing the promoted particulate to provide a reduced sorbent
composition comprising a reduced-valence noble metal.
[0014] In accordance with a further aspect of the present
invention, there is provided a process for removing sulfur from a
hydrocarbon-containing fluid stream. The process comprises the
steps of: contacting the hydrocarbon-containing fluid stream with a
sorbent composition comprising a reduced-valence noble metal and a
support in a desulfurization zone under conditions such that there
is formed a desulfurized fluid stream and a sulfurized sorbent;
separating the desulfurized fluid stream from the sulfurized
sorbent; regenerating at least a portion of the separated
sulfurized sorbent in a regeneration zone so as to remove at least
a portion of the sulfur therefrom and provide a regenerated
desulfurized sorbent; reducing the desulfurized sorbent in an
activation zone to provide a reduced sorbent composition which will
effect the removal of sulfur from the hydrocarbon-containing fluid
stream when contacted with the same; and returning at least a
portion of the reduced sorbent composition to the desulfurization
zone.
DETAILED DESCRIPTION OF THE INVENTION
[0015] In accordance with a first embodiment of the present
invention, a novel sorbent composition suitable for removing sulfur
from hydrocarbon-containing fluids is provided. The sorbent
composition comprises a support and a reduced-valence noble
metal.
[0016] The support may be any component or combination of
components which can be used as a support for the sorbent
composition of the present invention to help promote the
desulfurization process of the present invention. Preferably, the
support is an active component of the sorbent composition. Examples
of suitable support components include, but are not limited to,
zinc oxide and any suitable inorganic and/or organic carriers.
Examples of 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
combinations thereof. Examples of suitable organic carriers
include, but are not limited to, activated carbon, coke, charcoal,
carbon-containing molecular sieves, and combinations thereof. A
preferred support comprises zinc oxide, silica, and alumina.
[0017] When the support comprises zinc oxide, the zinc oxide used
in the preparation of the sorbent composition of the present
invention can be either in the 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 combinations
thereof. Preferably, the zinc oxide is in the form of powdered zinc
oxide.
[0018] When the support comprises zinc oxide, the zinc oxide will
generally be present in the 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 80 weight percent zinc oxide, and most preferably in an
amount in the range of from 20 to 70 weight percent zinc.
oxide.
[0019] When the support comprises silica, the silica used in the
preparation of the 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 the 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 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.
[0020] When the support comprises silica, the silica will generally
be present in the 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 most preferably in an amount in the
range of from 15 to 55 weight percent silica.
[0021] When the support comprises alumina, the alumina used in
preparing the 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, for example, boehmite or pseudoboehmite.
[0022] When the support comprises alumina, the alumina will
generally be present in the sorbent composition of the present
invention in an amount in the range of from about 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 5
to about 20 weight percent alumina, and most preferably in an
amount in the range of from 5 to 15 weight percent alumina.
[0023] The sorbent composition of the present invention further
comprises a noble metal. The noble metal can be present in the form
of an elemental noble metal, a noble metal-containing compound, a
noble metal oxide, or a noble metal oxide precursor. The metal
component of the noble metal is preferably selected from the group
consisting of platinum, palladium, rhodium, ruthenium, osmium,
iridium, and combinations thereof. Most preferably, the metal
component of the noble metal is platinum.
[0024] A portion, preferably a substantial portion, of the noble
metal is present in the form of a reduced-valence noble metal. The
valence of the reduced-valence noble metal is reduced to a value
which is less than the valence of the noble metal in its common
oxidized state, preferably less than 3, more preferably less than
2, and most preferably 0.
[0025] The noble metal will generally be present in the sorbent
composition of the present invention in an amount in the range of
from about 0.05 to about 30 weight percent noble metal based on the
total weight of the sorbent composition, preferably in an amount in
the range of from about 0.1 to 15 weight percent noble metal, and
most preferably in an amount in the range of from 0.2 to 5 weight
percent noble metal.
[0026] It is preferred that at least 10 weight percent of the noble
metal present in the sorbent composition is in the form of a
reduced-valence noble metal, more preferably at least 40 weight
percent of the noble metal is a reduced-valence noble metal, and
most preferably at least 80 weight percent of the noble metal is a
reduced-valence noble metal.
[0027] The reduced-valence noble metal will generally be present in
the sorbent composition of the present invention in an amount in
the range of from about 0.01 to about 25 weight percent
reduced-valence noble metal based on the total weight of the
sorbent composition, preferably in an amount in the range of from
about 0.1 to 10 weight percent reduced-valence noble metal, and
most preferably in an amount in the range of from 0.2 to 4 weight
percent reduced-valence noble metal.
[0028] In accordance with a second embodiment of the present
invention, a process for making the inventive sorbent composition
of the first embodiment of the present invention is provided.
[0029] In the manufacture of the sorbent composition of the present
invention, the support is generally prepared by combining the
support compounds, described above, together in appropriate
proportions, described above, by any suitable method or manner
known in the art which provides for the intimate mixing of such
components to thereby provide a substantially homogeneous mixture
comprising the support components, preferably a substantially
homogeneous mixture comprising zinc oxide, silica, and alumina. Any
suitable means for mixing the support component can be used to
achieve the desired dispersion of the 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 components.
[0030] The support components 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 support 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 like. For example, if the resulting
support mixture is in the form of a wet mix, the wet mix can be
densified, dried, calcined, and thereafter shaped, or particulated,
through the granulation of the densified, dried, calcined mix to
form granulates. Also for example, when the resulting support
mixture 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 {fraction (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 support particulates,
preferably cylindrical extrudates, are then dried and calcined
under conditions as disclosed herein.
[0031] More preferably, the resulting support mixture 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
mean particle size generally in the range of from about 1
micrometer to about 500 micrometers, preferably in the range of
from about 10 micrometers to about 300 micrometers. Spray drying is
known in the art and is discussed in Perry's Chemical
Engineers'Handbook, 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. As used herein, 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., 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 framed
sieves with a pan on the bottom. The material undergoes sifting for
a period of about 10 minutes; therafter, 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.
[0032] The spray dried support particulate can then be dried under
a drying condition as disclosed herein and calcined under a
calcining condition as disclosed herein. Preferably, calcining is
conducted in an oxidizing atmosphere, such as in the presence of
oxygen or air, to form a dried and calcined support particulate.
The calcination can be conducted under any suitable condition that
removes residual water and oxidizes and combustibles.
[0033] The resulting dried and calcined support particulate is then
incorporated with the noble metal, described above. The noble metal
may be incorporated in, on, or with the dried and calcined support
particulate by any suitable means or method known in the art such
as, for example, impregnating, soaking, spraying, and combinations
thereof. The preferred method of incorporating the noble metal into
the dried and calcined support particulate is impregnating using
standard incipient wetness impregnation techniques. The preferred
method uses an impregnating solution comprising the desired
concentration of the noble metal so as to ultimately provide a
promoted particulate which can be subjected to drying, calcining,
and reduction to provide the sorbent composition of the present
invention. The impregnating solution can be any aqueous or an
organic solvent solution in amounts of such solution which suitably
provides for the impregnation of the dried and calcined support
particulates. A preferred impregnating solution is formed by
dissolving a noble metal-containing compound in water. It is
acceptable to use somewhat of an acidic solution to aid in the
dissolution of the noble metal-containing compound. It is more
preferred for the particulates to be impregnated with the noble
metal by use of a solution containing tetraamine platinum(II)
nitrate dissolved in water.
[0034] Generally, the amount of the noble metal incorporated,
preferably impregnated, onto, into, or with the support is an
amount which provides, after the promoted particulate material has
been dried calcined, and reduced, a sorbent composition having an
amount of the reduced-valence noble metal as disclosed herein.
[0035] Once the noble metal has been incorporated in, on, or with
the dried and calcined support particulate, the noble
metal-promoted particulates are subsequently dried and calcined
under conditions disclose herein to thereby provide a dried,
calcined, noble metal-promoted particulate comprising an unreduced
noble metal.
[0036] Generally, a drying condition, as referred to herein, can
include a temperature in the range of from about 180.degree. F. to
about 290.degree. F., preferably in the range of from about
190.degree. F. to about 280.degree. F., and more preferably in the
range of from 200.degree. F. to 270.degree. 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
sub-atmospheric (i.e., about 28 inches of mercury) 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.
Any drying method(s) 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.
[0037] Generally, a calcining condition, as referred to herein, can
include a temperature in the range of from about 400.degree. F. to
about 1800.degree. F., preferably in the range of from about
500.degree. F. to about 1600.degree. F., and more preferably in the
range of from 800.degree. F. to about 1500.degree. 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 psia.
[0038] The dried, calcined, noble metal-promoted particulates are
thereafter subjected to reduction with a suitable reducing agent,
preferably hydrogen, under reducing conditions, to thereby provide
a reduced sorbent composition comprising a reduced-valence noble
metal having a valence which is less than that of the unreduced
noble metal. Reduction can be carried out at a temperature in the
range of from about 100.degree. F. to about 1500.degree. F. and at
a pressure in the range of from about 15 pounds per square inch
absolute (psia) to about 1,500 psia. Such reduction is carried out
for a time period sufficient to achieve the desired level of noble
metal reduction. Such reduction can generally be achieved in a time
period in the range of from about 0.01 hour to about 20 hours.
[0039] In accordance with a third embodiment of the present
invention, a desulfurization process is provided which employs the
novel sorbent composition described herein.
[0040] The hydrocarbon-containing fluid feed employed in the
desulfurization process of this embodiment of the present invention
is preferably a sulfur-containing hydrocarbon fluid, more
preferably, gasoline or diesel fuel, most preferably
cracked-gasoline or diesel fuel.
[0041] The hydrocarbon-containing fluid described herein as
suitable feed in the process of the present invention comprises a
quantity of 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 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 the process of the
present invention. The amount of sulfur in the desulfurized
hydrocarbon-containing fluid following treatment in accordance with
the process of the present invention is less than about 100 parts
per million (ppm) sulfur 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.
[0042] As used herein, the term "gasoline" denotes a mixture of
hydrocarbons boiling in the range of from about 100.degree. F. to
about 400.degree. F., or any fraction thereof. Examples of suitable
gasoline include, but are not limited to, hydrocarbon streams in
refineries such as naphtha, straight-run naphtha, coker naphtha,
catalytic gasoline, visbreaker naphtha, alkylate, isomerate,
reformate, and the like and combinations thereof.
[0043] As used herein, the term "cracked-gasoline" denotes a
mixture of hydrocarbons boiling in the range of from about
100.degree. F. to about 400.degree. 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 cracking 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.
[0044] As used herein, the term "diesel fuel" denotes a mixture of
hydrocarbons boiling in the range of from about 300.degree. F. to
about 750.degree. F., or any fraction thereof. Examples of suitable
diesel fuels include, but are not limited to, light cycle oil,
kerosene, jet fuel, straight-run diesel, hydrotreated diesel, and
the like and combinations thereof.
[0045] As used herein, 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
(CS.sub.2), mercaptans (RSH), organic sulfides (R-S-R), organic
disulfides (R-S-S-R), thiophene, substituted thiophenes, organic
trisulfides, organic tetrasulfides, benzothiophene, alkyl
thiophenes, alkyl 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.
[0046] As used herein, the term "fluid" denotes gas, liquid, vapor,
and combinations thereof.
[0047] As used herein, 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.
[0048] The desulfurizing of the hydrocarbon-containing fluid is
carried out in a desulfurization zone 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 desulfurize the hydrocarbon-containing
fluid to produce a desulfurized hydrocarbon-containing fluid and a
sulfurized sorbent composition.
[0049] In desulfurizing the 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.
[0050] In desulfurizing the 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 psia. 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.degree. F. to about 1000.degree. F., it is
presently preferred that the temperature be in the range of from
about 400.degree. F. to about 800.degree. F. when treating a
cracked-gasoline and in the range of from about 500.degree. F. to
about 900.degree. F. when treating a diesel fuel.
[0051] 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 desulfurization zone
to which the hydrocarbon-containing fluid is charged. In the
practice of the present invention, such WHSV should be in the range
of from about 0.5 hr.sup.-1 to about 50 hr.sup.-1, preferably in
the range of from about 1 hr.sup.-1 to about 20 hr.sup.-1. The
desulfurizing (i.e., desulfurization) of the hydrocarbon-containing
fluid should be conducted for a time sufficient to affect the
removal of at least a substantial portion sulfur from such
hydrocarbon-containing fluid.
[0052] In desulfurizing the hydrocarbon-containing fluid, it is
presently preferred that an agent be employed which interferes with
any possible chemical or physical reacting of the olefinic 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.
[0053] If desired, during the desulfurizing of the
hydrocarbon-containing fluid according to the 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 desulfurization of a hydrocarbon-containing
fluid such as cracked-gasoline or diesel fuel.
[0054] It is presently preferred, when the desulfurization zone is
in a fluidized bed reactor system, that a sorbent composition be
used having a mean particle size, as described herein, in the range
of from about 1 micrometer to about 500 micrometers. Preferably,
such sorbent composition has a mean particle size in the range of
from about 10 micrometers to about 300 micrometers When a fixed bed
reactor system is employed as the desulfurization zone of the
present invention, the sorbent composition should generally have a
particulate size in the range of from about {fraction (1/32)} inch
to about 1/2 inch diameter, preferably in the range of from about
{fraction (1/32)} 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 (m.sup.2/g), preferably in the range of
from about 1 m.sup.2/g to about 800 m.sup.2/g.
[0055] After sulfur removal in the desulfurization zone, the
desulfurized hydrocarbon-containing fluid and sulfurized sorbent
composition can then be separated by any manner or method known in
the art that can separate a solid from a fluid, preferably 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 combinations
thereof. The desulfurized hydrocarbon-containing fluid, preferably
desulfurized gaseous cracked-gasoline or desulfurized gaseous
diesel fuel, can then be recovered and preferably liquefied.
liquefaction of such desulfurized hydrocarbon-containing fluid can
be accomplished by any manner or method known in the art.
[0056] The sulfurized sorbent is then regenerated in a regeneration
zone under a set of conditions that includes temperature, total
pressure, and sulfur removing agent partial pressure. The
regenerating is carried out at a temperature generally in the range
of from about 100.degree. F. to about 1500.degree. F., preferably
in the range of from about 800.degree. F. to about 1200.degree. F.
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.
[0057] The sulfur removing agent, i.e., regenerating agent, is a
composition(s) 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 gas(es) 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.
[0058] In carrying out the process of the present invention, a
stripper zone can be inserted before and/or after, preferably
before, regenerating the sulfurized sorbent composition in the
regeneration zone. Such stripper zone, preferably utilizing a
stripping agent, will serve to remove a portion, preferably all, of
any hydrocarbon(s) 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.
[0059] 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 psia. The temperature for such
stripping can be in the range of from about 100.degree. F. to about
1000.degree. 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 composition(s)
that helps to remove a hydrocarbon(s) from the sulfurized sorbent
composition. Preferably, the stripping agent is nitrogen.
[0060] After regeneration, and optionally stripping, the
desulfurized sorbent composition is then subjected to reducing,
i.e., activating, in an activation zone with a reducing agent,
preferably hydrogen, so that at least a portion of the unreduced
noble metal incorporated on, in, or with the sorbent composition is
reduced to thereby provide a reduced sorbent composition comprising
a reduced-valence noble metal. Such reduced-valence noble metal is
incorporated on, in, or with such sorbent composition in an amount
that provides for the removal of sulfur from the
hydrocarbon-containing fluid according to a process of the present
invention.
[0061] In general, when practicing the process of the present
invention, the reducing, i.e., activating, of the desulfurized
sorbent composition is carried out at a temperature in the range of
from about 100.degree. F. to about 1500.degree. 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 carried out
for a time sufficient to achieve the desired level of noble metal
reduction. Such reduction can generally be achieved in a time
period in the range of from about 0.01 hour to about 20 hours.
[0062] Following the reducing, i.e., activating, of the
regenerated, desulfurized sorbent composition, at least a portion
of the resulting reduced (i.e., activated) sorbent composition can
be returned to the desulfurization zone.
[0063] When carrying out the desulfurization process of the present
invention, the steps of desulfurizing, regenerating, reducing
(i.e., activating), and optionally stripping before and/or after
such regenerating, can be accomplished in a single zone or vessel
or in multiple zones or vessels. The desulfurization zone can be
any zone wherein desulfurizing 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 reducing, i.e., activating,
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.
[0064] When carrying out the process of the present invention in a
fixed bed reactor system, the steps of desulfurizing, regenerating,
reducing, and optionally stripping before and/or after such
regenerating are accomplished in a single zone or vessel. When
carrying out the process of the present invention in a fluidized
bed reactor system, the steps of desulfurizing, regenerating,
reducing, and optionally stripping before and/or after such
regenerating are accomplished in multiple zones or vessels.
[0065] When the 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 cracked-gasoline containing low levels of sulfur is
desired.
[0066] When the 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.
[0067] The following example is presented to further illustrate
this invention and is not to be construed as unduly limiting the
scope of this invention.
EXAMPLE
[0068] This example demonstrates that a noble metal-promoted
sorbent composition comprising a reduced-valence noble metal, zinc
oxide, alumina, and silica is effective to desulfurize
cracked-gasoline.
[0069] Batch 1 of the support for the inventive sorbent was made by
mixing 22.0 lbs. of distilled water and 315.79 grams of acetic acid
in a Cowles dissolver to create a water/acid solution. A 6.375 lb.
quantity of aluminum hydroxide powder (Disperal Alumina Powder,
available from CONDEA Vista Company, Houston, Tex.) was added to
the water/acid solution and mixed for 30 minutes to create an
alumina slurry. A 20.02 lb. quantity of diatomaceous earth
(Celite.TM. Filter Cell, available from Mansville Sale Corporation,
Lampoc, Calif.) and a 25.03 lb. quantity of zinc oxide powder
(available from Zinc Corporation, Monaca, Pa.) were mixed together
for 15 minutes to create powdered mixture. The powdered mixture was
slowly added to the alumina slurry over a period of about 15
minutes and then mixed for about 25 minutes to create a sorbent
base slurry.
[0070] The sorbent base slurry was then formed into sorbent base
particulate using a counter-current spray drier (Niro Atomizer
Model 68, available from Niro Atomizer Inc., Columbia, Md.). The
sorbent base slurry was charged to the spray drier wherein it was
contacted in a particulating chamber with air flowing through the
chamber. The air flowing through the chamber had an inlet
temperature of approximately 320.degree. C. and an outlet
temperature of approximately 140.degree. C., and operated to
partially dry the sorbent base slurry into a sorbent base
particulate. The sorbent base particulate was then further dried in
an oven by ramping the oven temperature at 3.degree. C./min to
150.degree. C. and holding at 150.degree. C. for 1 hour. The dried
sorbent base particulate was then calcined by ramping the oven
temperature at 5.degree. C./min to 635.degree. C. and holding at
635.degree. C. for 1 hour.
[0071] Batches 2, 3, and 4 of the sorbent support were made using
the same process as Batch 1, except the powdered mixture and
alumina slurry were mixed for 30 minutes, rather than 25 minutes,
to make the sorbent base slurry. The sorbent base particulate of
Batches 1-4 were then mixed together prior to impregnation with the
noble metal promoter.
[0072] A 90 gram quantity of the mixed sorbent base particulate of
Batches 1-4 was then impregnated with 27 grams of a tetraamine
platinum (II) nitrate solution (containing 2% Pt) using incipient
wetness techniques and dried for 30 minutes using a blow drier. The
impregnated sorbent was then put in an oven and further dried by
ramping the oven temperature at 2.degree. C./min to 120.degree. C.
and holding at 120.degree. C. for 1 hour. The dried sorbent was
then calcined by ramping the oven temperature at 2.degree. C./min
to 510.degree. C. and holding at 510.degree. C. for 1 hour. The
resulting noble metal-promoted sorbent contained about 0.6 wt. %
platinum.
[0073] The platinum-promoted sorbent was then sieved to provide a
10 gram quantity of platinum-promoted sorbent which passed through
the 50 mesh sieve but was retained above the 230 mesh sieve (i.e.,
-50/+230 mesh). The 10 gram quantity of platinum-promoted sorbent
was placed in a reactor (1 inch I.D. fluidized bed reactor with
clam shell heater) and heated to 700.degree. F. in flowing nitrogen
at a rate of 150 cc/min for a period of 30 minutes. The nitrogen
was then turned off and hydrogen was charged to the 700.degree. F.
reactor at a rate of 300 cc/min for 75 minutes to reduce the
platinum-promoted sorbent.
[0074] Catalytically cracked gasoline (CCG) having a sulfur content
of 345 ppmw was then charged to the 728.degree. F. reactor at a
rate of 13.4 ml/hr. Simultaneously with the CCG, nitrogen and
hydrogen were charged to the reactor at 150 cc/min and 150 cc/min,
respectively. After 1 hour, a 9.54 gram effluent sample was taken
from the 749.degree. F. reactor and designated Sample 1 A. After 2
hours, a 10.21 gram effluent sample was taken from the 759.degree.
F. reactor and designed Sample 2A. After 3 hours, a 13.35 gram
effluent sample was taken from the 739.degree. F. reactor and
designated Sample 3A. After 4 hours, a 12.41 gram effluent sample
was taken from the 714.degree. F. reactor and designated Sample
4A.
[0075] The CCG and hydrogen flow to the reactor was then terminated
and the reactor temperature was reduced to about 230.degree. C. The
reactor temperature was then increased to 900.degree. F. in flowing
nitrogen at 240 cc/min over a period of 45 minutes. The
platinum-promoted sorbent was then oxidized by charging air to the
907.degree. F. reactor at 60 cc/min for 75 minutes. The air was
then turned off and the reactor temperature was reduced to, and
maintained at, 700.degree. F. for 20 minutes. Hydrogen was then
charged to the 720.degree. F. reactor at a rate of 300 cc/min for
83 minutes to reduce the platinum-promoted sorbent. CCG having a
sulfur content of 345 ppmw was then charged to the 720.degree. F.
reactor at a rate of 13.4 ml/hr, along with nitrogen and hydrogen
flowing at a rate of 240 cc/min and 300 cc/min, respectively. After
1 hour, a 7.7 gram effluent sample was taken from the 759.degree.
F. reactor and designated Sample 1 B. After 2 hours, a 15.72 gram
effluent sample was taken from the 767.degree. F. reactor and
designated Sample 2B. After 3 hours, a 11.04 gram effluent sample
was taken from the 768.degree. F. reactor and designated Sample 3B.
After 4 hours, a 9.47 gram effluent sample was taken from the
766.degree. F. reactor and designated Sample 4B. The CCG and
hydrogen flow to the reactor was then terminated and the reactor
temperature was reduced to about 230.degree. C.
[0076] Samples 1A-4A (Cycle A) and 1B-4B (Cycle B) were then
analyzed for sulfur content using x-ray fluorescence. The results
are summarized in Table 1.
1TABLE 1 Desulfurization of CCG Containing 345 ppmw Sulfur with
Reduced-Valence Platinum-Promoted Sorbent Cycle A Cycle B Sample
(ppmw Sulfur) (ppmw Sulfur) 1 5 5 2 <5 10 3 10 15 4 45 15
[0077] As can readily be seen from Table 1, the reduced-valence
noble metal-promoted sorbent composition of the present invention
is effective for removing sulfur from catalytically cracked
gasoline.
[0078] Reasonably 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.
* * * * *