U.S. patent application number 09/746540 was filed with the patent office on 2002-08-22 for slurry hydroprocessing for heavy oil upgrading using supported slurry catalysts.
Invention is credited to Ferrughelli, David Thomas, Gorbaty, Martin Leo, Hou, Zhiguo, Olmstead, William Neergaard, Riley, Kenneth Lloyd, Roby, Bearden JR., Sabottke, Craig Young.
Application Number | 20020112987 09/746540 |
Document ID | / |
Family ID | 25001281 |
Filed Date | 2002-08-22 |
United States Patent
Application |
20020112987 |
Kind Code |
A1 |
Hou, Zhiguo ; et
al. |
August 22, 2002 |
Slurry hydroprocessing for heavy oil upgrading using supported
slurry catalysts
Abstract
A slurry hydroprocessing process (SHP) where a hydrocarbon
feedstock is treated at slurry hydrotreating conditions, in the
presence of a hydrogen containing treat gas and in the presence of
a supported metallic catalyst which is a supported sulfide of a
metal selected from the group of non-noble Group VIII metals, Group
VIB metals and mixtures thereof where the support is an inorganic
oxide and where the catalyst has an average diameter of about 0.5
to about 100 microns to obtain a first product stream comprising
the catalyst and a hydroprocessed feedstream; separating the first
product into a catalyst-free product stream and a
catalyst-containing stream and recycling at least a portion of the
catalyst-containing stream back to the hydroprocessing step.
Inventors: |
Hou, Zhiguo; (Baton Rouge,
LA) ; Roby, Bearden JR.; (Baton Rouge, LA) ;
Riley, Kenneth Lloyd; (Baton Rouge, LA) ; Sabottke,
Craig Young; (Baton Rouge, LA) ; Ferrughelli, David
Thomas; (Flemington, NJ) ; Gorbaty, Martin Leo;
(Westfield, NJ) ; Olmstead, William Neergaard;
(Murray Hill, NJ) |
Correspondence
Address: |
EXXONMOBIL RESEARCH AND ENGINEERING COMPANY
P.O. Box 900
Annandale
NJ
08801-0900
US
|
Family ID: |
25001281 |
Appl. No.: |
09/746540 |
Filed: |
December 15, 2000 |
Current U.S.
Class: |
208/108 ;
208/217; 208/251H; 208/254H |
Current CPC
Class: |
C10G 47/12 20130101 |
Class at
Publication: |
208/108 ;
208/217; 208/251.00H; 208/254.00H |
International
Class: |
C10G 047/26 |
Claims
What is claimed is:
1. A process comprising the steps of: (a) slurry hydroprocessing
(SHP) a hydrocarbon feedstock, at slurry hydroprocessing
conditions, in the presence of a hydrogen containing treat gas and
in the presence of a supported metallic catalyst comprising a
supported sulfide of at least one Group VIII non-noble metal and at
least one metal selected from the group consisting of non-noble
Group VIII metals, Group VIB metals and mixtures thereof wherein
said support is an inorganic refractory oxide, carbon and mixtures
thereof, and wherein said catalyst has an average diameter of about
0.5 to about 100 microns to obtain a first product stream
comprising said catalyst and a hydroprocessed feedstream; (b)
separating said first product into a catalyst-free product stream
and a catalyst-containing stream; (c) recycling at least a portion
of the catalyst-containing stream to said hydroprocessing step
(a).
2. The process of claim 1 wherein said hydrocarbon feedstock is
selected from the group consisting of heavy feeds, distillates,
asphaltenes, deasphalted oils, cycle oils, FCC tower bottoms, gas
oils, hydrocrackates, dewaxed oil, slack waxes, Fischer Tropsch
waxes, raffinates, naphthas, hydrotreated oils and mixtures
thereof.
3. The process of claim 1 wherein said catalyst is selected from a
supported sulfided metallic catalyst wherein said metal is selected
from molybdenum, nickel, tungsten, cobalt and mixtures thereof.
4. The process of claim 1 wherein said inorganic refractory oxide
catalyst support is selected from alumina, silica and mixtures
thereof.
5. The process of claim 1 wherein said catalyst is a supported
sulfided material prepared from a precursor represented by the
formula (X).sub.b(Y).sub.c where X is a Group VIII non-noble metal
and Y is a Group VIII non-noble metal or a VIb metal and the molar
ratio of b to c is 0.1/1 to 3/1.
6. The process of claim 1 wherein said catalyst comprises at least
three metals and wherein at least one of said metals is a group
VIII non-noble metal and at one of said metals is a group VIB
metals where the ratio of group VIB metal to group VIII non-noble
metal is from about 10:1 to about 1:10.
7. The process of claim 1 wherein said catalyst is prepared from a
precursor is represented by the formula
(X).sub.b(MO).sub.c(W).sub.dO.sub- .z; wherein X is a non-noble
Group VIII metal, and the molar ratio of b to (c+d) is 0.5/1 to
3/1; the molar ratio of c:d is .gtoreq.0.01/1; and
z=[2b+6(c+d)]2.
8. The process of claim 1 wherein said Group VIII non-noble metal
is nickel.
9. The process of claim 8 wherein said catalyst has an essentially
amorphous x-ray diffraction pattern with crystalline peaks at
d=2.53 Angstroms and d=1.70 Angstroms.
10. The process in claim 1 wherein said separation of said first
product into a catalyst free and catalyst containing stream is
accomplished using a cross-flow filtering step.
11. The process of claim 10 wherein said catalyst has a particle
size of about 0.5 to 25 microns.
12. The process of claim 10 wherein filter media aids comprising
particles in the size range of about 5 to about 200 microns are
utilized.
13. The process of claim 10 wherein said cross-flow filtering step
is integral to said slurry hydroprocessing step.
14. The process of claim 1 wherein said process further comprised
separating volatiles from said first product stream prior to said
separation step (b).
15. The process of claim 1 further comprising removing gaseous
overheads during said separation step (b).
16. The process of claim 15 wherein when said overheads comprise a
hydrogen containing gas, further comprising recycling said hydrogen
containing gas to said step (a).
17. The process of claim 1 further comprising separating said
catalyst-free product stream into gaseous and liquid hydrocarbon
components prior to said step (c).
18. The process of claim 1 wherein said supported metallic catalyst
has a median pore diameter of between 10.0 and 35.0 nm.
Description
FIELD OF THE INVENTION
[0001] An embodiment of the instant invention is directed to an
integrated slurry hydroprocessing process.
BACKGROUND OF THE INVENTION
[0002] Slurry hydroprocessing (SHP) is a technology capable of
providing a low cost means for upgrading heavy crudes. Numerous
patents exist that teach the use of hydroprocessing to obtain
upgraded products from heavy crudes.
[0003] U.S. Pat. Nos. 3,622,495 and 3,622,498 describe a slurry
process for effecting the hydroconversion of a hydrocarbonaceous
charge stock containing sulfurous compounds. The process utilizes
finely divided catalyst selected from the metals of Group V-B, VI-B
or VIII of the periodic table. Preferred metallic components are
vanadium, chromium, iron, cobalt, nickel, niobium, molybdenum,
tantalum, and/or tungsten. The Group VIII noble metals are not
generally considered for use. The catalyst may be combined with a
refractory inorganic oxide carrier, but the process is said to be
facilitated when the sulfide of the metal is unsupported.
[0004] U.S. Pat. No. 4,525,267 is directed to a process for
hydrocracking hydrocarbons for residuum conversion. At least part
of the catalyst utilized in the hydrocracking is extracted from the
reaction zone and subjected to a hydrotreatment regeneration
followed by recycle back to the hydrocracking step. The process is
said to reduce coke production to a considerable degree.
[0005] While conventional slurry hydroprocessing has met with
varying degrees of commercial success, there still remains a need
in the art for processes and slurry catalysts that result in
improved yields and selectivity.
[0006] As the supply of low sulfur, low nitrogen crudes decrease,
refineries are processing crudes with greater sulfur and nitrogen
contents at the same time that environmental regulations are
mandating lower levels of these heteroatoms in products.
Consequently, a need exists for increasingly efficient
desulfurization and denitrogenation catalysts.
[0007] What is needed in the art is an improved process and
catalysts which upgrade heavy feeds economically and
effectively.
SUMMARY OF THE INVENTION
[0008] An embodiment of the instant invention is directed to a
process comprising the steps of:
[0009] (a) slurry hydroprocessing (SHP) a hydrocarbon feedstock, at
slurry hydroprocessing conditions, in the presence of a hydrogen
containing treat gas and in the presence of a supported metallic
catalyst comprising a supported sulfide of at least one Group VIII
non-noble metal and at least one metal selected from the group
consisting of non-noble Group VIII metals, Group VIB metals and
mixtures thereof wherein said support is an inorganic refractory
oxide carbon or mixtures thereof and wherein said catalyst has an
average diameter of about 0.5 to about 100 microns to obtain a
first product stream comprising said catalyst and a hydroprocessed
feedstream;
[0010] (b) separating said first product into a catalyst-free
product stream and a catalyst-containing stream
[0011] (c) recycling at least a portion of the catalyst-containing
stream to said hydroprocessing step (a).
BRIEF DESCRIPTION OF THE FIGURES
[0012] FIG. 1 depicts one possible flow scheme for the instant
invention. Feed and slurry catalyst enter the hydroprocessing
reactor along with hydrogen. The reactor effluent is then passed to
a separator zone that may comprises a cross-flow filtration
chamber, as shown here, or other separation means, where the
effluent is separated into a catalyst-free stream and a
catalyst-containing stream. The catalyst containing stream, after
withdrawal of a purge stream to control solids concentration in the
reactor liquid, is recycled to the hydroprocessing reactor along
with fresh feed. The catalyst free stream is then separated into
gaseous and liquid products. The gaseous products include hydrogen
which can then be recycled to the slurry hydroprocessing
reactor.
[0013] FIG. 2 depicts another possible flow scheme where volatiles
are removed before the separation of the first product into a
catalyst-free and catalyst-containing stream.
[0014] FIG. 3 depicts another possible embodiment where the
volatiles are removed from the first product stream during
separation into a catalyst free and catalyst containing stream. The
effluent from the slurry hydroprocessing reactor can be passed
through a cooler (not shown) and introduced into a gas-liquid
separator or disengaging means where the hydrogen gas, along with
ammonia and hydrogen sulfide by-products from the hydroprocessing
reactions, may be separated from the liquid effluent and recycled
back for reuse in the hydrogen stream. The recycled gas is usually
passed through a scrubber (not shown) to remove hydrogen sulfide
and ammonia. This is usually recommended because of the inhibiting
effect of such gases on the kinetics of hydrotreating and also to
reduce corrosion in the recycle circuit. Fresh make-up hydrogen can
be introduced into the recycle circuit. The gas-free liquid from
the gas-liquid separator then enters a solids separator, or a
filter, vacuum flash, centrifuge or the like, in order to divide
the hydrotreating reactor effluent into a catalyst-containing
stream and a product stream
DETAILED DESCRIPTION OF THE INVENTION
[0015] An aspect of the instant invention provides an integrated
slurry hydroprocessing process which provides a more effective and
efficient process by improving separation of product from the
slurry.
[0016] The process may also include separating said catalyst-free
product stream into gaseous and liquid hydrocarbon components prior
to said step (c).
[0017] A wide range of petroleum and chemical hydrocarbon
feedstocks can be hydroprocessed in accordance with the present
invention. Suitable feedstocks, which will typically contain both
nitrogen and sulfur, include whole and reduced petroleum crudes,
atmospheric and vacuum residua, asphaltenes, deasphalted oils,
cycle oils, FCC tower bottoms, gas oils, including atmospheric and
vacuum gas oils and coker gas oils, light to heavy distillates
including raw virgin distillates, hydrocrackates, hydrotreated
oils, dewaxed oils, slack waxes, Fischer-Tropsch waxes, raffinates,
naphthas, and mixtures thereof.
[0018] The heavy feeds which may be treated in accordance with the
teachings herein are heavy feeds, defined as feeds having an API
gravity of <10-15.degree. with a viscosity of .gtoreq.60
centistokes at 60 C, including heavy crude oils and vacuum
resids.
[0019] The light feeds which can be processed herein include feeds
such as kerosene, home heating oil, straight run atmospheric gas
oils, straight run vacuum gas oils etc. and mixtures thereof.
Typically, such feeds will have a boiling point in the range of
about 60 to about 1050.degree. F. (about 16 to about 566.degree.
C.).
[0020] In an embodiment of the instant invention (illustrated in
FIG. 2, a feedstream and slurry hydroprocessing (SHP) catalyst,
along with hydrogen are fed to a reactor, which includes an
external pump-around line and crossflow filter chamber. The
crossflow filter chamber, which operates at reactor pressure and
temperature, consists of a vapor zone and liquid zone. Hydrogen and
gaseous products are removed from the vapor zone to a downstream
separator. Upgraded catalyst-free liquid is withdrawn through the
crossfiow filter, and the resultant catalyst-containing liquid is
recycled to the reactor, after removal of a suitable purge stream
to control solids level in the reactor. The recycle stream can be
fed directly to the reactor or premixed with the fresh feed stream.
Additionally, fresh catalyst may be used in combination with the
recycled catalyst.
[0021] Catalysts which may be utilized in the invention are
supported catalysts. The supports may comprise inorganic refractory
oxides such as silica, alumina and mixtures thereof, carbon and
mixtures of carbon and inorganic refractory oxides. The catalyst
will preferably comprise sulfides of molybdenum, nickel, tungsten,
cobalt, or mixtures thereof. The catalyst will have an average
diameter ranging from about 0.5 to about 100 microns and can be
prepared directly from pre-sized inorganic oxide materials or
obtained by reducing the size of commercially available
hydrotreating catalysts.
[0022] Preferably, the catalysts will be prepared ex-situ by
crushing commercially available catalysts and catalyst supports to
obtain the desired catalyst diameter. It is believed that the
selection and control of the particle size distribution of the
catalyst enhances solid-liquid separation and significantly
improves the hydrodesulfurization process. The ex-situ preparation
provides flexibility to control the particle hardness and attrition
resistance, intrinsic catalyst activity and other catalyst
properties important to the process performance and physical
separation.
[0023] An example of a useable catalyst is a supported sulfided
material prepared from a precursor represented by the formula:
(X).sub.b(Y).sub.c where X is a Group VIII non-noble metal and Y is
a Group VIII non noble metal or a VIb metal. The molar ratio
described as the ratio of b:c is 0.1/1 to 3/1, preferably 0.25/1 to
2/1, more preferably 0.35/1 to 1/1, and most preferably 0.4/1 to
0.7/1.
[0024] Another useable sulfided catalyst comprises at least three
metals wherein at least one of said metals is a Group VIII
non-noble metal and at least one of said metals is a Group VIB
metals where the ratio of Group VIB metal to Group VIII non-noble
metal is from about 10:1 to about 1:10, supported on an inorganic
oxide.
[0025] In yet another preferred embodiment the supported sulfided
metallic catalyst has a precursor represented by the formula:
(X).sub.b(Mo).sub.c(W).sub.dO.sub.z; wherein X is a non-noble Group
VIII metal, and the molar ratio of b to (c+d) is 0.1/1 to 3/1; the
molar ratio of c to d is .gtoreq.0.01/1; and z=[2b+6(c+d)]2.
[0026] In another preferred embodiment of the present invention the
Group VIII non-noble metal is selected from Ni and Co.
[0027] In still another preferred embodiment of the present
invention the Group VIII metal is Ni, and the X-ray diffraction
pattern of the catalyst is essentially amorphous with crystalline
peaks at d=2.53 Angstroms and d=1.70 Angstroms.
[0028] In yet another preferred embodiment of the present invention
the molar ratio of b to (c+d) is 0.25/1 to 2.0/1 and the molar
ratio of c to d is 1/10 to 10/1.
[0029] Desired catalysts that are used to process heavy feeds have
median pore diameters between 10.0 and 35.0 nm. For distillate
boiling range feeds, preferred median pore diameters are between
12.0 and 20.0 nm; and most preferred median pore diameters are
between 14.0 and 18.0 nm. For heavy feeds, preferred median pore
diameters are .gtoreq.30 nm. These median pore diameters are
typically determined by Hg porosimetry.
[0030] The process conditions in the hydroprocessing reactor will
depend on such things as the particular feed being treated. Such
conditions are readily adjustable by the skilled artisan within the
ranges herein taught. General process conditions for SHP include
temperatures of about 500.degree. to about 900.degree. F. (about
260 to about 482.degree. C.), preferably about 650 to about
850.degree. F. (about 385 to about 454.degree. C.) and most
preferably about 725 to about 850.degree. F. (about 343 to about
454.degree. C.) and pressures from about 300 to about 2500 psig
(about 2170 to about 17,339 kPa), preferably about 500 to about
2500 psig (3,549 to about 17,339 kPa) and most preferably about 800
to about 1000 psig (about 5,617 kPa to about 6996 kPa). The
hydrogen treat gas rate is suitably about 200 to 2000 SCF/B
(standard cubic feet per barrel) (36 to 360 m.sup.3/m.sup.3),
preferably about 500 to 1500 SCF/B (90 to 270 m.sup.3/m.sup.3). The
residence time is suitably from about 0.5 to 4 hours and preferably
about 1 to 2 hours. For heavy feeds, it is preferable to attain
about 1025+.degree. F. to 1025-.degree. F. (552+.degree. C. to
552-.degree. C.) conversion of at least about 30%, preferably about
40%, and most preferably from about 50 to 60%. Catalyst
concentration on feed will range from about 1 wt % to 30 wt %,
preferably about 5 to about 20 wt %.
[0031] It is to be understood that the hydroprocessing of the
present invention can be practiced in one or more reaction zones
and can be practiced in either countercurrent flow or cocurrent
flow mode. By countercurrent flow mode we mean a process mode
wherein the feedstream flows countercurrent to the flow of
hydrogen-containing treat gas.
[0032] The slurry hydroprocessing process of the present invention
can be practiced by introducing a given feedstock into a slurry
hydroprocessing reactor. Before being passed to the hydroprocessing
reactor, the feed may be mixed with a hydrogen containing gas
stream and heated to a reaction temperature in a furnace or
preheater. Alternatively, the hydrogen gas can be introduced
directly into the hydroprocessing reactor. The reactor contains the
slurried catalyst as previously described. Recycle of the reactor
effluent via a pump is optional to provide mixing within the
reactor zone.
[0033] In the preferred embodiment, the catalyst/solids separation
from the product oil is accomplished by a cross-flow filtering step
integrated with a pump around loop in the slurry reactor. In the
turbulent cross-flow filtration zone there is minimal build-up of
filter cake, which minimizes problems associated with filter
binding. Other established separation steps such as gravity
settling, centrifugation and other commonly known techniques may
also be employed in combination with cross-flow filtration to
enhance the process performance.
[0034] The most efficient process will employ a catalyst particle
size and functionality that has been selected for the reactor
conversion objectives and the cross-flow filtering system. The
skilled artisan can readily select such parameters. In the most
preferred embodiment, catalyst particle diameters on the order of
0.5 to 25 microns in size will be utilized. The performance of the
cross-flow filtering step may be enhanced by the use of filter
media aids. These filter media aids can be specially sized
particles in the size range of about 5 to 200 microns that are used
to pre-coat the filter media surface to enhance filter performance.
Filter design can either be a back-flushed or continuously purged
configuration.
[0035] The cross-flow filtration step can be either close coupled
to the reactor in an external pump around loop or integrated into
the reactor design as a section of the reactor in combination with
a pump around zone (not shown in the figures).
[0036] In most slurry hydroprocessing operations it is desirable to
separate substantially all of the catalyst from the liquid
hydrocarbon product. Thus, the separation step is typically carried
out under conditions which maximize separation to produce a
recyclable active catalyst product having a maximum concentration
which can be pumped or conveyed to the feed. This is typically in
the range of from about 5 weight percent ("wt. %") to about 75 wt.
%, preferably in the range of from about 10 wt. % to about 50 wt.
%, and even more preferably in the range of from about 15 wt. % to
about 35 wt. %. Except for cross-flow filtration, the separation
step may comprise the use of centrifuges, cyclones, filters or even
settling and draw-off.
[0037] The following examples are meant to be illustrative and not
limiting.
EXAMPLE 1
[0038] A supported slurry catalyst was prepared by reducing the
size of commercially available NiMo catalyst (Catalyst A). A sample
of Catalyst A was wet-ball milled overnight and dried at
100-110.degree. C. for 3-4 hours. After calcining at 400.degree. C.
for 3 hours, a fine powdered catalyst sample was obtained with
measured average particle size at 3.6 microns. Prior to
hydrotreating tests, it was pre-treated with hydrogen and hydrogen
sulfide under 1000 psig (6996 kPa) of total pressure
(H.sub.2/H.sub.2S=90/10, v/v) at 725.degree. F. (385.degree. C.)
for 60 minutes both to sulfide and to activate the catalyst. Table
1 provides additional physical properties of this catalyst.
1TABLE 1 Physical Properties of Pre-treated Slurry Catalyst A
Physical Properties of Slurry Catalyst A Mo, wt % 5.9 Ni, wt % 1.73
Surface Area, m.sup.2/g 121 Pore Volume, cc/g 0.41 Median Particle
Size, .mu.m 3.6
EXAMPLE 2
[0039] A typical hydroprocessing experiment involved charging an
autoclave with 100 g of resid (ALVR, Brent VR), and appropriate
amount of catalyst chosen on the basis of wt % metal on feed. The
mixture was stirred at 1500 RPM at 775.degree. F. (413.degree. C.)
under 1000 psig (6996 kPa) of hydrogen pressure for 2 hours.
Hydrogen was flowed through during the test to maintain an
effective hydrogen partial pressure of about 900 psig (6307 kPa).
The autoclave was then cooled to 300.degree. F. (149.degree. C.)
and vented, and the liquid containing the catalyst was discharged.
The product was separated by filtration through a two-layer of
filter composed of one sheet of #2 and one sheet of#3 Whatman
filter papers. The solid was washed with toluene and dried under
vacuum over night. The product oil was analyzed for metals, sulfur
and Microcarbon Residue (MCR).
2TABLE 2 Mild Slurry hydroprocessing tests of supported slurry
Catalyst A. Conditions 775.degree. F. (413.degree. C.), 1000 psig
H.sub.2 (6996 kPa), 2 hours. The catalyst was charged at 12 wt % on
feed equivalent to 0.5 wt % Mo on feed. Total Liquid Arab Light
Product Brent Vacuum Resid Vacuum Resid Quality Feed Cycle 1 Feed
Cycle 2 Ni, ppm 10 3.67 27.3 16.0 V, ppm 38 1.77 95.7 18.7 S wt %
1.17 0.26 4.18 1.37 MCR wt % 14.9 9.68 24.3 12.8
[0040]
3TABLE 3 Limited Catalyst Recycle Tests of the Supported Slurry
Catalyst A on ALVR. Conditions: 775.degree. F. (413.degree. C.),
1000 psig (6996 kPa) H.sub.2, 2 hours, the catalyst was charged at
12 wt % on feed for the first cycle, equivalent to 0.6 wt % Mo on
feed. Total Liquid Product ALVR Slurry Hydroprocessing Quality Feed
Cycle 1 Cycle 2 Cycle 3 Ni, PPM 27.1 14.5 20.5 21.6 V, PPM 95.7
18.6 23.9 25.3 S, wt % 4.18 1.44 1.64 1.70 CCR, wt % 24.3 13.5 14.5
14.8
[0041] In summary, it has been demonstrated that the supported
slurry catalysts could be utilized to improve the quality of feeds.
In the case of the slurry Catalyst A (Table 2), better upgrading
results were achieved for both Brent VR and ALRV, and HDS was
particularly higher due to Ni components of the catalyst. The
recycle test, though not under optimum conditions, indicated that
the supported slurry catalyst could provide reasonable recycle
activity maintenance (Table 3). In addition, since the supported
slurry catalysts are made ex-situ, their particle size can be
better controlled and the size distribution can be made
particularly narrow, thus providing for better solid-liquid
separation relative to soft, small particle catalysts.
* * * * *