U.S. patent application number 12/113305 was filed with the patent office on 2009-01-22 for dispersed metal sulfide-based catalysts.
This patent application is currently assigned to INTEVEP, S.A.. Invention is credited to Jose Cordova, Francisco Granadillo, Roger Marzin, Pedro Pereira, Guaicaipuro Rivas, Bruno Solari, Luis Zacarias.
Application Number | 20090023965 12/113305 |
Document ID | / |
Family ID | 40265388 |
Filed Date | 2009-01-22 |
United States Patent
Application |
20090023965 |
Kind Code |
A1 |
Pereira; Pedro ; et
al. |
January 22, 2009 |
DISPERSED METAL SULFIDE-BASED CATALYSTS
Abstract
The invention provides a catalyst composition, which includes an
emulsion of an aqueous phase in an oil phase, wherein the aqueous
phase comprises an aqueous solution containing a group 6 metal and
a group 8, 9 or 10 metal. The metals can be provided in two
separate emulsions, and these emulsions are well suited for
treating hydrocarbon feedstocks.
Inventors: |
Pereira; Pedro; (US)
; Rivas; Guaicaipuro; (San Pedro De Los Altos, VE)
; Cordova; Jose; (Caracas, VE) ; Granadillo;
Francisco; (San Pedro De Los Altos, VE) ; Marzin;
Roger; (San Antonio De Los Altos, VE) ; Solari;
Bruno; (Los Teques, VE) ; Zacarias; Luis; (San
Antonio De Los Altos, VE) |
Correspondence
Address: |
BACHMAN & LAPOINTE, P.C.
900 CHAPEL STREET, SUITE 1201
NEW HAVEN
CT
06510
US
|
Assignee: |
INTEVEP, S.A.
Los Teques
VE
|
Family ID: |
40265388 |
Appl. No.: |
12/113305 |
Filed: |
May 1, 2008 |
Current U.S.
Class: |
585/250 ;
502/220; 502/221; 502/313; 502/315 |
Current CPC
Class: |
B01J 27/0515 20130101;
C10G 45/08 20130101; B01J 23/85 20130101; B01J 27/051 20130101;
B01J 23/883 20130101; B01J 23/88 20130101; B01J 27/049 20130101;
B01J 35/0013 20130101; B01J 37/082 20130101 |
Class at
Publication: |
585/250 ;
502/221; 502/313; 502/315; 502/220 |
International
Class: |
C07C 5/00 20060101
C07C005/00; B01J 27/043 20060101 B01J027/043; B01J 27/051 20060101
B01J027/051; B01J 23/24 20060101 B01J023/24; B01J 23/38 20060101
B01J023/38 |
Claims
1. A catalyst composition of the general formula:
B.sub.xM.sub.yS.sub.[(1.1 to 4.6)y+(0.5 to 4)x] where B is a group
8, 9 or 10 (group VIIIB, CAS version) non-noble metal and M is a
group 6 (group VIB, CAS version) metal, and wherein the ratio y/x
is greater than or equal to 0.05 and less than or equal to 15.
2. The composition of claim 1, wherein the ratio y/x is greater
than or equal to 0.2 and less than or equal to 6.
3. The composition of claim 1, wherein the ratio y/x is 3.
4. A catalyst composition of the general formula:
B.sub.xM1.sub.yM2.sub.zO.sub.(2 to 3)zS.sub.[(0.3 to 2)y+(0.5 to
4)x] where B is a group 8, 9 or 10 (group VIIIB, CAS version)
non-noble metal and M1 and M2 are group 6 (group VIB, CAS version)
metals, and wherein the ratio y/x is greater than or equal to 0.05
and less than or equal to 15, and the ratio z/x is greater than or
equal to 1 and less than or equal to 14.
5. The composition of claim 4 wherein the ratio y/x is greater than
or equal to 0.2 and less than or equal to 6.
6. The composition of claim 4 wherein the ratio z/x is greater than
or equal to 10 and less than or equal to 14.
7. The composition of claim 6 wherein the ratio z/x is 12.
8. The composition of claim 4 wherein the ratio z/x is greater than
or equal to 1 and less than or equal to 5.
9. The composition of claim 8 wherein the ratio z/x is 3.
10. The composition of claim 1 or claim 4, wherein the catalyst
composition is an ultradispersed suspension within a hydrocarbon
solvent.
11. The composition of claim 10 wherein the ultradispersed
suspension is characterized by a median particle diameter between
30 nm and 6,000 nm.
12. The composition of claim 10 wherein the ultradispersed
suspension is characterized by a median particle diameter between
60 nm and 2,500 nm.
13. A catalyst composition, comprising: an emulsion of an aqueous
phase in an oil phase, wherein the aqueous phase comprises an
aqueous solution containing a group 6 metal and a group 8, 9 or 10
metal.
14. The composition of claim 13, wherein the group 6 metal is a
metal sulfide.
15. The composition of claim 13, wherein the group 6 metal is a
salt precursor to a metal sulfide.
16. The composition of claim 15, wherein the salt precursor
comprises an organometallic compound.
17. The composition of claim 16, wherein the organometallic
compound is selected from the group consisting of naphthenates,
acetates, metal oxides and combinations thereof.
18. The composition of claim 13, wherein the group 6 metal is
selected from the group consisting of molybdenum, tungsten and
mixtures thereof.
19. The composition of claim 13, wherein the group 6 metal is
molybdenum.
20. The composition of claim 13, wherein the group 8, 9 or 10 metal
is selected from the group consisting of iron, cobalt, nickel and
mixtures thereof.
21. The composition of claim 13, wherein the group 8 metal is
nickel.
22. The composition of claim 13, wherein the group 6 metal is
molybdenum and the group 8 metal is nickel.
23. The composition of claim 13, wherein an atomic ratio of nickel
to combined nickel and molybdenum is greater than 0 and less than
0.2.
24. The composition of claim 23, wherein the atomic ratio is
0.1.
25. The composition of claim 13, wherein the oil phase comprises a
hydrocarbon selected from the group consisting of HVGO, HHGO and
combinations thereof.
26. The composition of claim 13, wherein the emulsion has a ratio
by weight of aqueous phase to oil phase of between 5 and 25 wt
%.
27. The composition of claim 13, wherein the emulsion has an
average droplet size of between 0.1 and 20 .mu.m.
28. The composition of claim 13, wherein the emulsion has a ratio
by weight of surfactant to total emulsion of greater than 0 and
less than or equal to 0.1.
29. The composition of claim 13, wherein the emulsion has a ratio
by weight of oil phase to combined oil and water phase of between
0.70 and 0.94.
30. The composition of claim 13, wherein the emulsion comprises a
first emulsion containing said group 6 metal and a second emulsion
containing said group 8, 9 or 10 metal.
31. A method for preparing an at least bi-metallic ultradispersed
catalyst comprising the steps of: preparing at least one first
precursor solution containing a metal salt of a metal of groups 8,
9 or 10 (Group VIII B, CAS version); preparing a second precursor
solution containing a group 6 metal salt (Group VI B, CAS version);
admixing the first and second precursor solutions with a
hydrocarbon feedstock to form separate first and second
microemulsions; and exposing the first and second microemulsions to
heat so as to decompose the first and second precursor solutions
and form the catalyst.
32. The method of claim 31, wherein the exposing step comprises
exposing the first and second microemulsions to the feedstock to be
treated and to heat.
33. The method of claim 31 further comprising the step of adding a
surfactant to any one of or a combination of the first and second
precursor solutions.
34. The method of claim 31 wherein the bi-metallic microemulsion
mixture is subjected to a decomposition process to form an
ultradispersed catalyst composition.
35. The method of claim 31 wherein the bi-metallic microemulsion
mixture is introduced into a reaction process to form an
ultradispersed catalyst composition within the reaction
process.
36. The method of claim 31, wherein the step of preparing the
second precursor solution further includes admixing a sulfuring
agent to form group 6 metal sulfide salt.
37. The method of claim 36, wherein the sulfuring agent is selected
from the group consisting of H.sub.2S, CS.sub.2, ammonium sulfide
and combinations thereof.
38. The method of claim 31 wherein preparing the second precursor
solution further includes admixing ammonium sulfide under
controlled conditions of pH to form thio salts.
39. The method of claim 31 further comprising the step of adding a
surfactant after addition of the hydrocarbon feedstock to enhance
microemulsion formation.
40. The method of claim 34 wherein the decomposition temperature is
between 150.degree. C. and 450.degree. C.
41. The method of claim 34 wherein the decomposition temperature is
between 225.degree. C. and 325.degree. C.
42. The method of claim 34 wherein the decomposition pressure is
between 1 atm and 70 atm.
43. The method of claim 34 wherein the decomposition pressure is
between 14 atm and 28 atm.
44. The method of claim 31, wherein the hydrocarbon feedstock is
selected from the group consisting of HVGO, HHGO and combinations
thereof.
45. The method of claim 31, wherein the first precursor solution
comprises a metal aqueous solution containing metal salts in an
amount between 7 and 14% by weight of the solution.
46. The method of claim 31, wherein the second precursor solution
comprises a metal aqueous solution containing metal salts in an
amount between 1 and 14% by weight of the solution.
47. The method of claim 31, wherein the step of preparing the first
precursor solution comprises mixing nickel acetate with water, and
wherein the step of preparing the second precursor solution
comprises mixing ammonium heptamolybdate with water and a sulfuring
agent.
48. The method of claim 31, wherein the first precursor solution
has an average droplet diameter of 2.7 microns, and a droplet size
distribution of between 1.5 and 7 microns.
49. The method of claim 31, wherein the second precursor solution
has an average droplet diameter of 3.6 microns, and a droplet size
distribution of between 0.3 and 13.4 microns.
50. A process for upgrading a hydrocarbon feedstock, comprising:
exposing the feedstock to an emulsion of an aqueous phase in an oil
phase, wherein the aqueous phase comprises an aqueous solution
containing a group 6 metal and a group 8, 9 or 10 metal; and
thermally decomposing the emulsion to produce a dispersed catalyst
of the group 6 metal and the group 8, 9 or 10 metal, whereby the
dispersed catalyst reacts with the feedstock to produce an upgraded
hydrocarbon product.
51. The process of claim 50, wherein the exposing step comprises
exposing the feedstock to a first emulsion containing the group 6
metal and a second emulsion containing the group 8, 9 or 10 metal.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to hydroconversion catalysts and, more
particularly, to synthesis of a dispersed catalyst which is useful
for deep catalytic hydrocarbon conversion.
[0002] Various catalytic industrial processes apply supported
heterogeneous catalysts. These catalysts contain dispersed metallic
active species over high surface area and/or on an acidic support.
The deposition of solids in the surface of this kind of catalyst
produces an activity loss, and this loss is even greater with heavy
and extra heavy feeds to the upgrading procedure.
[0003] Additionally there are slurry technologies, which are
characterized by the presence of very small catalyst particles
effectively dispersed in the medium. Catalyst can be fed as powder
(U.S. Pat. No. 4,303,634) or as oil-soluble precursors (U.S. Pat.
No. 4,470,295) such as molybdenum naphthenate. However, the need to
disperse the catalytic solids or oil-soluble compounds makes for
increased cost.
[0004] The need exists for an improved hydroconversion catalyst and
method for making and using same.
[0005] It is therefore the primary object of the present invention
to provide such a hydroconversion catalyst and a method for making
and using same.
[0006] Other objects and advantages will appear below.
SUMMARY OF THE INVENTION
[0007] According to the invention, the foregoing objects and
advantages have been attained.
[0008] According to the invention, a catalyst composition is
provided which comprises an emulsion of an aqueous phase in an oil
phase, wherein the aqueous phase comprises an aqueous solution
containing a group 6 metal (Group VI B, CAS version) and a group 8,
9 or 10 metal (Group VIII B, CAS version).
[0009] According to the invention, the catalyst can advantageously
be supplied to the feedstock in two separate or different
emulsions.
[0010] According to a further embodiment of the invention, a method
is provided for preparing an at least bi-metallic ultradispersed
catalyst comprising the steps of preparing at least one first
precursor solution containing a metal salt of a metal of groups 8,
9 or 10; preparing a second precursor solution containing a group 6
metal salt; admixing the first and second precursor solutions with
a hydrocarbon feedstock to form separate microemulsions; and
admixing the first and second microemulsions to form a bi-metallic
microemulsion mixture.
[0011] Still further, a process is provided for upgrading a
hydrocarbon feedstock, comprising exposing the feedstock to an
emulsion of an aqueous phase in an oil phase, wherein the aqueous
phase comprises an aqueous solution containing a group 6 metal and
a group 8, 9 or 10 metal; and thermally decomposing the emulsion to
produce a dispersed catalyst of the group 6 metal and the group 8,
9 or 10 metal, whereby the dispersed catalyst reacts with the
feedstock to produce an upgraded hydrocarbon product. According to
one embodiment, the residue or other feedstock is exposed to two
different emulsions each containing a component of the catalyst.
These emulsions can be injected into the reaction zone and exposed
to increased temperature which serves to decompose the emulsions
and generate the desired dispersed catalyst.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A detailed description of preferred embodiments of the
invention follows, with reference to the attached drawings,
wherein:
[0013] FIG. 1 schematically illustrates a process for making a
catalyst according to the invention;
[0014] FIGS. 2a and 2b illustrate micrography of catalyst particles
according to the invention;
[0015] FIGS. 3a and 3b illustrate an optical image of a molybdenum
emulsion and the droplet diameter distribution of same,
respectively;
[0016] FIGS. 4a and 4b illustrate an optical image of a nickel
emulsion and the droplet diameter distribution of same,
respectively; and
[0017] FIG. 5 is a graph showing catalytic activity of an emulsion
as a function of ratio of nickel to combined nickel and
molybdenum.
DETAILED DESCRIPTION
[0018] The invention relates to hydroconversion catalysts and, more
particularly, to synthesis of a dispersed catalyst which is useful
for deep catalytic hydrocarbon conversion, and to use of the
catalyst in hydroconversion processes.
[0019] A novel and successful form to feed a catalyst precursor is
provided. The present invention provides for use of this catalyst
in hydroconversion through in situ formation of active phase by
thermal decomposition of precursor compounds that contain the metal
species; high dispersion level of catalytic particles in the feed;
and high activity and better contact between the reactants and
active phases. This provides for a greater degree of probability
that big molecules which have previously caused diffusion problems
will instead be transformed.
[0020] The dispersed catalyst of the present invention provides an
alternative for upgrading heavy and extra heavy feeds, combining
the flexibility of thermal processes with the high performance of
hydrogen addition processes.
[0021] By using an emulsion system to obtain the catalyst, the
emulsions have a specific environment for producing small particles
with narrow size distribution and defined composition. In the
specific case of water and oil emulsions, the affinity between the
organic phase and the feedstock (residue with high viscosity) to be
converted, permits a good mixture and facilitates the interactions
and reactions that are necessary for the upgrading process.
[0022] Water/oil emulsions with very small droplet sizes are of
particular interest because each droplet provides a surfactant
protected aqueous compartment wherein specific amounts of
organometallic salts can be dissolved. These salts are precursors
of the final active metallic phase.
[0023] According to the invention, a process is provided for
producing small particles with narrow size distribution in the
sub-micron range. A defined composition from pre-catalytic
emulsions is disclosed for use in hydroconversion of heavy oils
such as crude oils, heavy crude oils, residual oils and refractory
heavy distillates (with an initial boiling point of around
500.degree. C.) into more desirable liquid and gas products.
[0024] In accordance with the invention, the dispersed or
ultra-dispersed catalyst is provided in the form of a water-oil
emulsion wherein the catalyst phase is dissolved in the water
droplets in the emulsion. The metal phase advantageously is
provided as one metal selected from groups 8, 9 or 10 of the
periodic table of elements, and another metal selected from group 6
of the periodic table of elements. These metals can also be
referred to as group VIA and VIIIA metals, or group VIB and group
VIIIB metals under earlier versions of the periodic table. The
metals of each class are advantageously prepared into different
emulsions, and these emulsions are useful as feed, separate or
together, to a reaction zone with a feedstock where the increased
temperature serves to decompose the emulsions and create a catalyst
phase which is dispersed through the feedstock as desired. While
these metals can be provided in a single emulsion or in different
emulsions, both well within the scope of the present invention, it
is particularly preferred to provide them in separate or different
emulsions.
[0025] The group 8-10 metal(s) can advantageously be nickel,
cobalt, iron and combinations thereof, while the group 6 metal can
advantageously be molybdenum, tungsten and combinations thereof.
One particularly preferred combination of metals is nickel and
molybdenum.
[0026] The method for preparing this emulsion is discussed below.
The end result can be a single water-oil emulsion where the water
droplets contain both the group 6 and group 8, 9 or 10 metals.
Alternatively, two separate emulsions can be prepared and fed to a
hydroconversion process, wherein each emulsion contains one of the
metallic phases. Either of these systems is considered to fall
within the broad scope of the present invention.
[0027] It is also within the scope of the invention to utilize more
than the two mentioned metals. For example, two or more metals from
group 8, 9 or 10 can be included in the catalyst phases of the
emulsions.
[0028] In further accordance with the invention, it has been found
that the catalyst phase is particularly effective when the group 6
metal is provided in the form of a sulfide metal salt. When
decomposed during the hydroconversion process, these sulfides form
sulfide metal particles which are advantageous in the subsequent
hydroconversion processes.
[0029] According to the invention, the emulsions are advantageously
prepared having a water droplet size of between 0.1 and 200 .mu.m,
preferably about 3 .mu.m, a ratio of water to hydrocarbon phase of
between 0.08 and 0.50, preferably 0.10 and 0.20, and a droplet size
distribution having at least 50 percent of the droplets within 10
microns of the average droplet size.
[0030] The emulsions can be prepared using surfactants, if
necessary. However, these emulsions have also successfully been
prepared relying only upon the natural surfactants within the
hydrocarbon phase. Thus, either and both of these types of
emulsions are considered to fall within the scope of the present
invention.
[0031] The hydrocarbon phase can be any suitable hydrocarbon which
will be readily miscible with the hydrocarbon feedstock ultimately
to be treated. Preferred types of hydrocarbon for use in making the
emulsion of the present invention include high vacuum residue gas
oil (HVGO), high hydrotreating gas oil (HHGO) and combinations
thereof. Of course other hydrocarbon phases can be used.
[0032] In order to prepare the catalyst emulsions of the present
invention, various methods can be used. However, one particularly
preferred method for preparing the emulsions of the present
invention involves forming one or more metallic aqueous solutions
of the metal salt precursors of the desired metallic phases. This,
or these, solutions are then formed into one or more emulsions with
a suitable hydrocarbon until water droplets containing the catalyst
phase have a desired droplet size and distribution. Such an
emulsion is generally stable for a sufficient period of time. If
there is any phase separation before the emulsion is used, a small
amount of further mixing quickly re-establishes the emulsion.
[0033] In order to prepare the metallic aqueous solution, a
suitable aqueous phase is obtained and the metal salt precursors
are mixed into the aqueous phase. In the case of the group 6 metal,
this can advantageously be done in the presence of a sulfuring
agent such as H.sub.2S, CS.sub.2, ammonium sulfide and mixtures
thereof. The sulfuring agent can be introduced into the aqueous
solution by making a sour water as the aqueous phase, for example
by adding sulfur in some dissolvable form to the water solution.
Once the group 6 metal is added to this solution, sulfide metals
are produced in the reaction system, and these sulfide metals are
advantageous in subsequent hydroconversion processes, particularly
in helping to provide high conversion rates for heavy fractions of
the feedstock to be treated and also in producing excellent
hydrodesulphurization (HDS) activity.
[0034] The metallic aqueous solution is combined with a hydrocarbon
phase such as HVGO (350.degree. C.+), with or without other
additives and/or non ionic surfactant or other surfactant
compounds, to produce a water in oil emulsion. The salt materials
that serve as precursor for the final sulfide metal particles
include organometallic compounds such as naphthenates, acetates and
other compounds such as oxides of Group 6 and 8, 9 or 10 metals and
mixtures thereof. In some instances, if the salt materials are
provided as organometallic compounds, then emulsions may not be
needed since this catalyst could itself be soluble with the organic
phase, that is, the hydrocarbon feedstock. The use of such a
catalyst is not outside the scope of the present invention. The
water-in-oil emulsion can be prepared for each metal and then
mixed, and/or different emulsion component concentrations can be
prepared as well.
[0035] The aqueous phase can be combined with a sulfuring agent
such as H.sub.2S, CS.sub.2, ammonium sulfide, or mixtures thereof.
These sulfuring agents produce sulfide metals in the reactions
system. During the hydroconversion process, the feed (distillation
vacuum residues) is mixed with one, two or more water in oil
emulsions in the proportion desirable to provide desired catalytic
activity. The process allows reaching conversion rates of greater
than 90% wt of 500.degree. C..sup.+ residue, greater than 88% wt
asphalting conversion, and greater than 86% wt conradson carbon
conversion.
[0036] In further accordance with the invention, a method is
provided for synthesizing a bi-metallic particle inside droplets of
a water-in-oil emulsion.
[0037] As indicated above, the present invention relates to
compositions for use in hydroconversion of heavy oils such as crude
oils, heavy crude oils, residual oils and refractory heavy
distillates.
[0038] Catalysts for these processes are synthesized inside the
droplets of a w/o-emulsion. This form provides an enhancement in
the dispersion of the catalysts through the feedstock, and allows
control of particle size, increasing catalyst surface area and
improving reaction efficiency.
[0039] In hydroconversion processes using the catalyst of the
present invention, the hydrocarbon feedstock is fed to a reactor
along with the catalyst phase, either as a single emulsion or as a
plurality of emulsions each containing one or more of these
catalyst metals as desired. These emulsions thermally decompose
under hydroconversion conditions and thereby create a very fine
particle-size catalyst dispersed throughout the feedstock. This
advantageously serves to provide excellent activity in the desired
process, be it conversion of heavy fractions,
hydrodesulphurization, or any other particular desired
reaction.
[0040] Suitable hydroconversion conditions according to the
invention include:
TABLE-US-00001 Parameter (units) Range Preferred Total Pressure
(bar) 150-220 180-200 H.sub.2 partial pressure (bar) 125-150
140-150 Reaction Temperature (.degree. C.) 440-475 448-460 Space
Velocity LHSV (h.sup.-1) 0.3-0.7 0.4-0.6 Gas to Liquid Ratio
(SCF/bbl) 3000-8000 4000-6000
[0041] FIG. 1 schematically illustrates a system for making the
catalyst system of the present invention.
[0042] The process starts with a source of group 6 metal, in this
instance shown as ammonium heptamolybdate (HMA) being fed to a
mixing tank 10. In addition, a source of nickel is fed to mixing
tank 12. Each of these is mixed with a source of water. FIG. 1 also
shows a source of sulfur being fed to tank 10 so as to prepare the
group 6 metal in sulfide form as desired. The resulting aqueous
solution from mixer 10 is fed through a pump 14 to a storage tank
16 and then through a further pump 18 to a mixer 20. At the same
time, a hydrocarbon for forming the oil phase of the desired
emulsion is provided from a tank 22. This hydrocarbon is fed
through a pump 24 to a mixer 26 and then to the same mixer 20 as
the group 6 metal aqueous solution. In addition, a surfactant can
be provided from a suitable source 28 and fed though a pump 30 to
mix with the oil phase in mixer 26. The result is that mixer 20
receives group 6 metal aqueous solution, hydrocarbon phase and,
optionally, a surfactant. The mixer imparts sufficient mixing
energy that an emulsion having the characteristics desired in the
present invention results and is stored in tank 32.
[0043] The group 8, 9 or 10 metal and water are mixed in mixer 12
to form an aqueous solution of the group 8, 9 or 10 metal. This
aqueous solution is fed to pump 34 and storage tank 36. From
storage tank 36 this solution is then passed through a pump 38 to a
mixer 40. The hydrocarbon for the oil phase from tank 22 is also
fed through pump 24 to mixer 42, and surfactant from tank 28 can be
fed through pump 44 to mixer 42, so that the hydrocarbon and
optionally the surfactant are mixed and then mixed with the metal
aqueous solution in mixer 40 to produce the desired emulsion having
characteristics as specified above, and this emulsion is stored in
tank 46. The separate emulsions from tanks 32 and tank 46 can then
be fed to suitable reactors for hydroconversion of feedstocks as
discussed above. FIG. 1 shows emulsions from these tanks being used
to feed two separate reactors. Of course, any number of reactors
could be fed with this catalyst emulsion phase. Also, while it is
within the scope of the invention to feed these emulsions together
into a single emulsion for use in treating the feedstock, it is
preferred to feed these emulsions to the reaction zone
separately.
[0044] It should of course be appreciated, as set forth above, that
this is only one method for making the catalyst system of the
present invention. Other alternatives could include preparing
additional emulsions, or forming an emulsion with all metals in a
single aqueous phase, or the like. Each of these alterations to the
disclosed method is considered to fall within the broad scope of
the present invention.
[0045] The catalyst system of the present invention is a novel form
to prepare and feed catalyst into the reactor. The catalysts are
synthesized from aqueous solutions containing metals of group 6 and
groups 8, 9 and/or 10 (Ni, Co, Fe, Mo, W, and the like, and
mixtures thereof) and an appropriate sulfiding agent such as
H.sub.2S, CS.sub.2, ammonium sulfide, and mixtures thereof. The
precursor catalysts in aqueous solution are formed into an emulsion
in a hydrocarbon such as High Vacuum Residue Gasoil (HVGO) or High
Hydro treating Gasoil (HHGO). The mixture of aqueous solution and
hydrocarbon can contain a non-ionic surfactant as well. The
resulting water-oil emulsion allows the catalysts to be spread into
the feedstock in an ultra-dispersed fashion. Further, a
carbonaceous additive can be injected to the reactor to control the
fluid dynamic. Carbon additives of many varieties can be used. One
suitable example is the type produced using delayed coker coke as
raw material. This material is dried, particle size distribution is
adjusted to fit between the range 212-850 .mu.m, and the material
is calcined in order to generate porosity having a pore size of
around 15 .ANG. and to increase the surface area to up to 200
m.sup.2/g (measured with CO.sub.2).
[0046] The following examples illustrate a catalyst preparation
method according to the invention.
EXAMPLE 1
Molybdenum Emulsion
[0047] An aqueous solution containing catalytic precursors was
prepared from ammonium heptamolybdate (AHM)
[(NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O]. The aqueous solution
was prepared having a concentration of 1-14 wt % in sour water. For
this example, the concentration was 10 wt %. The sour water was
prepared using ammonium sulfide [(NH.sub.4).sub.2S] at a
concentration of 0.1-14% wt. For this example, the concentration
was 0.2 wt %. The AHM reacts with ammonium sulfide to generate
soluble oxy-sulfurs.
[0048] A w/o emulsion was prepared using a ratio of mass of
surfactant to total mass of the emulsion (.gamma.) between 0 and
0.01 and a ratio by mass of oil to combined mass of aqueous
solution and oil ({acute over (.alpha.)}) of between 0.7 and 0.94.
The aqueous solution and the oil phase can be formed into an
emulsion without surfactants (only natural surfactants contained in
the oil, such as resins or naphthenic acids contained in HVGO), or
using a non-ionic surfactant with an Hydrophilic-Lipophilic Balance
(HLB) greater than 4. The use of surfactant enhances the stability
of the emulsion. Of course, other surfactants or mixtures thereof
may also be used. The components of the emulsion are mixed using a
static mixer and are fed to a reactor. Table 1 preferred ranges for
these components followed by those used in this example.
TABLE-US-00002 TABLE 1 Component (% wt/wt) AHM aqueous solution
(1-14%) 6.00-30.00 in sour water (0.2%) Surfactant 0-1.00 HVGO/HHGO
73.00-90.70 AHM aqueous solution 11.78 Surfactant 0.90 HVGO/HHGO
87.32
[0049] The w/o-emulsion was thermally decomposed at a temperature
between 150 and 420.degree. C. and a pressure between 100 and 300
bar to form the active catalyst Mo--S, which has a ratio of S/Mo of
greater than or equal to 1.0 and less than or equal to 3. Particle
size of the catalyst is in the sub-micron range. FIGS. 2a and 2b
show a typical HTEM micrography of catalyst particles, that is,
they show the stocked layers of molybdenum sulfide formed in the
media during the reaction.
[0050] Table 2 presents experimental metal content from a 100 Kg
batch of molybdenum emulsion with {acute over (.alpha.)}=0.879 and
.gamma.=0.006. This batch was used during a test-run.
TABLE-US-00003 TABLE 2 Hours on Deviation from stream Molybdenum
(ppmwt) theoretical value Date HOS (h) Theoretical Experimental (%)
3/07 91 5978 -6.59 10/07 259 6319 1.27 12/07 307 6400 6582 -2.84
15/07 379 6329 -1.11 17/07 427 5945 -7.11 19/07 474 6544 2.25
[0051] The emulsions showed thermal stability between room
temperature (21.degree. C.) and 80.degree. C. Experimental results
have demonstrated that during an incipient-phase separation of the
emulsion, any break can be easily reverted by mechanical
agitation.
[0052] FIGS. 3a and 3b show droplet diameter size distribution and
a digitalized optical image of molybdenum emulsion, respectively.
The droplets have an average diameter of 3.6 .mu.m and a
distribution between 0.3 and 13.4 .mu.m.
EXAMPLE 2
Nickel Emulsion
[0053] A water-oil emulsion was prepared from nickel acetate
[Ni(CH.sub.3COO).sub.2.H.sub.2O] aqueous solution (7-14% wt) and
HVGO or HHGO, with or without non-ionic surfactant. The
relationships .gamma. and {acute over (.alpha.)} were the same as
for the w/o molybdenum emulsion, between 0-0.01 and 0.70-0.94
respectively. Table 3 shows the component preferred ranges of the
emulsion and their concentration in the mixture, as well as
specific values for this example.
TABLE-US-00004 TABLE 3 Component (% wt/wt) [Ni (CH.sub.3
COO).sub.2.cndot.H.sub.2O] aqueous 6.00-30.00 solution 7-14% (0.2%)
Surfactant 0-1.00 HVGO/HHGO 73.00-90.70 [Ni
(CH.sub.3COO).sub.2.cndot.H.sub.2o] aqueous solution 26.31
Surfactant 0.90 HVGO/HHGO 72.78
[0054] The preparation parameters and control quality methods
applied for the water-oil nickel emulsion coincide with those that
have been applied for the molybdenum emulsion. FIGS. 4a and 4b show
the droplet diameter size distribution and a digitalized optical
image of the nickel emulsion, respectively. The droplets have an
average diameter of 2.7 .mu.m and a distribution between 1.5 and 7
.mu.m.
[0055] Results were obtained for a typical test-run ({acute over
(.alpha.)}=0.879 and .gamma.=0.006). The water-oil emulsion was
thermally decomposed at temperatures between 150 and 390.degree. C.
and pressures between 100 and 300 bar to form the active catalyst
Ni--S, which has a ratio of S/Ni of greater than or equal to 0.6
and less than or equal to 2. Particle size was in the sub-micron
range. Table 4 shows the nickel content of the different batches of
emulsion prepared during a test run.
TABLE-US-00005 TABLE 4 Hours on Deviation from stream Nickel
(ppmwt) theoretical value Date HOS (h) Theoretical Experimental (%)
1/07 37 7520 3.01 5/07 139 7012 -3.95 8/07 211 7300 7651 4.81 10/07
259 7247 -0.726 15/07 379 7791 6.73
EXAMPLE 3
Bi-Metallic Catalyst Synthesis
[0056] The synergy effect of NiMoS supported catalyst is well
known. However, this effect is not evident in dispersed catalyst
systems. Due to this fact, thermal decomposition of the
simultaneous nickel and molybdenum water-oil emulsions was tested.
The ratio of Ni/Ni+Mo was changed from 0 to 1 and HDS activity
measured at different points in this range. FIG. 5 shows HDS
activity results for solids obtained from simultaneous thermal
decomposition. It is clear that Ni enhances the performance of Mo
catalyst and the maximal synergistic effect was found at a ratio of
0.1. HTEM results evidenced particle size in the range of the
previous described particles (Mo--S and Ni--S).
[0057] It should be appreciated that a new catalyst system has been
provided in accordance with invention which produces fine or
ultra-dispersed catalyst particles and thereby greatly enhances
hydroconversion activity of the catalyst when exposed to a suitable
feed stock. It should also be appreciated that a method for making
a suitable emulsion containing the catalyst has been provided, and
that a process using this catalyst for hydroconversion has also
been provided.
[0058] The present disclosure is provided in terms of details of a
preferred embodiment. It should also be appreciated that this
specific embodiment is provided for illustrative purposes, and that
the embodiment described should not be construed in any way to
limit the scope of the present invention, which is instead defined
by the claims set forth below.
* * * * *