U.S. patent application number 11/491899 was filed with the patent office on 2006-11-16 for method for manufacturing hydrorefining catalyst, and metal recovery method.
Invention is credited to Yoshiki Iwata, Hiroki Koyama, Chikanori Nakaoka, Toru Saito.
Application Number | 20060258531 11/491899 |
Document ID | / |
Family ID | 26593526 |
Filed Date | 2006-11-16 |
United States Patent
Application |
20060258531 |
Kind Code |
A1 |
Koyama; Hiroki ; et
al. |
November 16, 2006 |
Method for manufacturing hydrorefining catalyst, and metal recovery
method
Abstract
A heavy oil is hydrorefined using a hydrorefining catalyst. A
spent hydrorefining catalyst whose activity has decreased is heat
treated (S1) and pulverized to obtained a regenerated powder (S2).
This regenerated powder is fractionated according to its metal
content (S3), formed (S6), dried (S7), and calcined (S7) to
manufacture a regenerated catalyst whose volume of pores with a
diameter of 50 to 2000 nm is at least 0.2 ml/g, and whose volume of
pores with a diameter over 2000 nm is no more than 0.1 mL/g. Using
this regenerated catalyst, a heavy oil containing at least 45 wt
ppm vanadium and nickel as combined metal elements is
hydrodemetalized, and the vanadium and nickel are recovered from
the used regenerated catalyst (SS1). Through hydrorefining, the
metal components are recovered more efficiently, and the spent
catalyst can be reused to manufacture a regenerated catalyst that
exhibits high reaction activity.
Inventors: |
Koyama; Hiroki; (Toda-shi,
JP) ; Saito; Toru; (Toda-shi, JP) ; Iwata;
Yoshiki; (Toda-shi, JP) ; Nakaoka; Chikanori;
(Toda-shi, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
26593526 |
Appl. No.: |
11/491899 |
Filed: |
July 25, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10310903 |
Dec 6, 2002 |
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11491899 |
Jul 25, 2006 |
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PCT/JP01/04802 |
Jun 7, 2001 |
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10310903 |
Dec 6, 2002 |
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Current U.S.
Class: |
502/337 |
Current CPC
Class: |
B01J 35/023 20130101;
C10G 45/08 20130101; B01J 35/108 20130101; Y02P 10/20 20151101;
B01J 23/85 20130101; B01J 23/94 20130101; Y02P 10/214 20151101;
B01J 35/10 20130101; B01J 37/0036 20130101; Y02P 10/23 20151101;
B01J 37/0009 20130101; C10G 45/04 20130101; C22B 7/009 20130101;
C22B 34/22 20130101; C22B 34/225 20130101; B01J 23/8877
20130101 |
Class at
Publication: |
502/337 |
International
Class: |
B01J 23/00 20060101
B01J023/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 8, 2002 |
JP |
2000-171427 |
Jul 19, 2002 |
JP |
2000-218139 |
Claims
1. A metal recovery method, comprising: hydrodemetalizing a heavy
oil containing vanadium and nickel using a hydrorefining catalyst;
and recovering at least one of the vanadium and nickel from the
catalyst used in the hydrodemetalization, wherein the hydrorefining
catalyst has been manufactured from, as raw material, a
hydrorefining catalyst which has been used in the hydrorefining of
heavy oils and which contains vanadium and nickel, by a method
comprising the steps of: obtaining a catalyst powder by pulverizing
the used hydrorefining catalyst; fractionating the catalyst powder
based on the content of at least one of vanadium and nickel; and
forming the obtained catalyst powder.
2. A metal recovery method in which metal is recovered from a used
hydrorefining catalyst that has been used in the hydrorefining of a
heavy oil, comprising the steps of: obtaining a catalyst powder by
pulverizing the used hydrorefining catalyst; fractionating the
obtained catalyst powder based on the amount of metal contained in
the catalyst powder; and recovering a metal component from the
fractionated catalyst powder.
3. The metal recovery method according to claim 2, wherein the used
hydrorefining catalyst contains vanadium and nickel, and the
pulverized catalyst powder is fractionated based on its content of
at least one of vanadium or nickel.
4. The metal recovery method according to claim 3, wherein the
fractionation is performed by sieving or magnetic separation.
5. A hydrorefining catalyst, comprising: a carrier formed from an
inorganic porous oxide; a hydrogenation active metal component
supported on the carrier; and vanadium distributed uniformly
throughout the catalyst, wherein the pore volume is at least 0.2
cm.sup.3/g for pores with a diameter of 50 to 2000 nm, and the pore
volume is no more than 0.1 cm.sup.3/g for pores with a diameter
over 2000 nm.
6. The hydrorefining catalyst according to claim 5, which is
manufactured from a catalyst that has been used in the
hydrorefining of a heavy oil.
7. The hydrorefining catalyst according to claim 5, wherein the
vanadium content is 0.2 to 10 wt % with respect to the catalyst
weight.
8. The hydrorefining catalyst according to claim 5, wherein a ratio
of vanadium content in an outer portion on a cross section of the
catalyst to that in an inner portion on the cross section of the
catalyst is 0.8 to 1.2.
9. The hydrorefining catalyst according to claim 5, wherein the
hydrogenation active metal includes at least one of molybdenum or
tungsten, and at least one of nickel or cobalt.
Description
CROSS-REFERENCE
[0001] This application is a Divisional Application of U.S.
application Ser. No. 10/310,903 filed on Dec. 6, 2002, which is a
Continuation Application of International Application No.
PCT/JP01/04802 which was filed on Jun. 7, 2001 claiming the
conventional priority of Japanese patent Applications No.
2000-171427 filed on Jun. 8, 2000 and No. 2000-218139 filed on Jul.
19, 2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a method for manufacturing a
regenerated catalyst using a spent catalyst that has been used in
the hydrorefining of a petroleum distillate and for reusing the
regenerated catalyst. It also relates to a method with which the
vanadium and other metals contained in a heavy oil are recovered by
hydrorefining.
[0004] 2. Description of the Related Art
[0005] A hydrorefining catalyst is generally manufactured by
supporting molybdenum and other such hydrogenation active metal
components on a porous carrier such as alumina. Hydrorefining
reduces the amount of sulfur, nitrogen, metals such as vanadium,
and so forth in a heavy oil. Hydrorefining involves bringing a
hydrocarbon oil into contact with hydrogen in the presence of a
catalyst, cracking the sulfur compounds and other such hetero
compounds, and separating these out as hydrogen sulfide, ammonia,
and the like.
[0006] When hydrorefining is continued for an extended period of
time, coke and metals are deposited into the catalyst pores and
lower the catalytic activity. This degradation is particularly
pronounced when the hydrocarbon oil is a heavy oil. Accordingly, a
used desulfurization catalyst whose catalytic activity has
decreased is removed as a spent catalyst and replaced with a new
catalyst. The removed spent catalyst can be disposed of as waste by
burying it after any oils have been removed and, in some cases,
after metals such as vanadium and molybdenum have been recovered.
The remaining alumina from which the metals have been recovered is
also sometimes utilized in applications other than as a catalyst,
such as a raw material for aluminum sulfate.
[0007] A spent catalyst in which very little vanadium or other
metals have been deposited is also sometimes reused as a catalyst
after the removal of coke. It may also be reused after the metals
have been taken out by dissolution.
[0008] Still, the activity of a catalyst obtained by a conventional
recycling method is not as high as that of a new catalyst. Also,
the mechanical strength is diminished by treatments such as
calcination performed in order to remove the coke. This decrease in
mechanical strength is a problem in that the catalyst breaks up
into a powder when repacked into the reactor. Consequently, the
reuse of such catalysts has been limited.
[0009] Hydrorefining can also be thought of as a treatment by which
vanadium and other metals are recovered from a petroleum distillate
by means of a catalyst, in which case the metal content in the
catalyst that has been used in hydrorefining (spent catalyst) must
be raised in order to recover the metals more efficiently.
Hydrorefining catalysts have not been studied from this standpoint
up to now.
[0010] The present invention was achieved in an effort to solve the
problems encountered with the above conventional art, and a first
object thereof is to provide a method for manufacturing a
hydrorefining catalyst that exhibits high activity in a specific
reaction by using a catalyst that has been used in hydrorefining. A
second object of the present invention is to provide a method for
recovering metals at a high efficiency through hydrorefining.
SUMMARY OF THE INVENTION
[0011] A first aspect of the present invention provides a method
for manufacturing a catalyst using, as raw material, a
hydrorefining catalyst which has been used in the hydrorefining of
a heavy oil and which contains vanadium and nickel, comprising the
steps of obtaining a catalyst powder by pulverizing the used
hydrorefining catalyst, fractionating the catalyst powder based on
the content at least one of vanadium or nickel, and forming the
obtained catalyst powder. The activity of a hydrorefining catalyst
is markedly degraded by metal build-up, and this metal build-up
occurs more on the outer surface of the catalyst particles and less
in the center. In view of this, a catalyst that has been used in
hydrorefining (hereinafter referred to as a spent catalyst) can be
pulverized and reformed into a regenerated catalyst. A regenerated
catalyst with higher activity is obtained by using the portion at
the center of the spent catalyst, which has undergone less activity
degradation, as the outer surface of the regenerated catalyst.
[0012] In the manufacturing method of the present invention, the
fractionation can be performed by sieving or magnetic separation.
The manufacturing method of the present invention can further
comprise the step of drying and calcining of the formed catalyst
powder.
[0013] Furthermore, in the manufacturing method of the present
invention, it is preferable if the catalyst powder is adjusted as a
volume of pores of the catalyst with a diameter of 50 to 2000 nm,
which are macropores that are effective for the diffusion of the
metal compounds in the heavy oil into the catalyst interior, is
large, such as 0.2 cm.sup.3/g or greater, for example, and the
volume of pores with a diameter of 2000 nm or more, which are
macropores that lower the mechanical strength, is small, such as
0.1 cm.sup.3/g or less. Accordingly, the regenerated catalyst has a
large metal build-up capacity, its activity is decreased less by
metal build-up, and the demetalization activity is particularly
high. Therefore, a catalyst of relatively high activity can be
manufactured from a spent catalyst, and since the catalyst is
recycled, the final amount of waste material is reduced.
[0014] According to the present invention, a heavy oil containing
vanadium and nickel can be hydrodemetalized using a hydrorefining
catalyst that has been manufactured by the above-mentioned method
for manufacturing the hydrorefining catalyst, and the vanadium or
nickel or both can be recovered from the manufactured catalyst used
in the hydrodemetalization. The vanadium or nickel or both can be
recovered by oxidizing roasting.
[0015] A second aspect of the present invention provides a method
for recovering metal from a hydrorefining catalyst that has been
used in the hydrorefining of a heavy oil, comprising the steps of
obtaining a catalyst powder by pulverizing the used hydrorefining
catalyst; fractionating the obtained catalyst powder according to
the amount of metal contained in the catalyst powder; and
recovering the metal component from the fractionated catalyst
powder. A high concentration of metal builds up on a spent catalyst
used in hydrorefining, and particularly on the outer surface of the
spent catalyst. This metal can be recovered from the catalyst on
which the metal component is deposited at a high yield by
pulverizing the catalyst and then fractionating out the catalyst
powder with a high metal content. In actual practice, iron is
deposited on the outermost surface of a spent catalyst. In view of
this, if the spent catalyst is pulverized into a powder, and the
portion of the powder containing a larger amount of iron (which
interacts strongly with a magnetic field) is sorted out, this
powder will at the same time contain large amounts of vanadium and
nickel. Therefore, by subjecting a pulverized spent catalyst powder
to magnetic separation and sorting out the powder containing iron,
it is possible to obtain the portion of the spent catalyst
containing more vanadium and nickel, which affords higher metal
recovery efficiency.
[0016] A third aspect of the present invention provides a
hydrorefining catalyst, comprising a carrier formed from an
inorganic porous oxide; a hydrogenation active metal component
supported on this carrier; and vanadium distributed uniformly
throughout the catalyst, wherein the pore volume is at least 0.2
cm.sup.3/g for pores with a diameter of 50 to 2000 nm, and the pore
volume is no more than 0.1 cm.sup.3/g for pores with a diameter
over 2000 nm. A catalyst used in the hydrorefining of a heavy oil
normally contains vanadium, and a regenerated catalyst regenerated
by the manufacturing method of the present invention has vanadium
uniformly dispersed throughout the catalyst. It is preferable that
a ratio of vanadium content in an outer portion in the catalyst to
vanadium content in an inner portion in the catalyst is from 0.8 to
1.2, particularly from 0.9 to 1.1. It is also preferable for the
vanadium content to be 0.2 to 10 wt % with respect to the catalyst
weight.
[0017] The hydrogenation active metal of the hydrorefining catalyst
of the present invention can include at least one of molybdenum and
tungsten, and at least one of nickel and cobalt. This allows a
regenerated catalyst with excellent mechanical strength to be
obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a flow chart of a specific example of the method
for manufacturing a hydrorefining catalyst according to the present
invention; and
[0019] FIG. 2 is a schematic of the apparatus used in the magnetic
separation in the method for manufacturing a hydrorefining catalyst
according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
Spent Catalyst
[0020] In this specification, the term "spent catalyst" refers to a
hydrorefining catalyst that has been used in the hydrorefining of a
heavy oil and whose activity has thereby been diminished. A spent
catalyst is deemed to be one whose hydrorefining activity, such as
its desulfurization activity, has dropped to the point that, if a
reaction rate constant of a fresh catalyst at a specific
temperature is assumed to be 100%, the reaction rate constant at
this specific temperature is 80% or less, and particularly 50% or
less. The reaction rate constants for the desulfurization and
demetalization reactions are determined, provided that the
desulfurization reaction can be expressed in a quadratic equation
and the demetalization reaction can be expressed in a linear
equation (linear expression).
[0021] It is also favorable to use a spent catalyst in which
hydrorefining has been accompanied by the build-up of nickel and
vanadium in a total metal weight of 1 to 30 wt %, and particularly
2 to 25 wt %, and especially 3 to 20 wt %.
[0022] It is particularly favorable if the catalyst used in
hydrorefining has been used in hydrodesulfurization. This is
because whereas a relatively large amount of metal builds up on the
inside of a catalyst used in demetalization, with a catalyst used
in desulfurization there is relatively little metal build-up in the
interior, so the activity in the interior is relatively high. A
catalyst in which hydrogenation active metal components are
supported on a carrier whose principal component is alumina can be
used to advantage as a hydrorefining catalyst.
[0023] The hydrorefining catalyst preferably contains alumina in an
amount of at least 60%, and especially at least 75%, with respect
to the catalyst weight. This alumina is preferably one obtained by
calcining pseudo-boehmite at 450 to 850.degree. C. (normally called
.gamma.-alumina). Besides alumina, this catalyst may also include
silica-alumina, zeolite, boria, titania, zirconia, magnesia,
phosphorous, or another compound oxide.
[0024] It is favorable for the hydrogenation active metal
components supported on the hydrorefining catalyst to be Group 6,
8, 9, or 10 elements, and particularly one or more element selected
from among molybdenum, tungsten, nickel, and cobalt. It is
preferable for these elements to be contained in the catalyst in
the form of a metal, oxide, or sulfide. It is preferable for these
elements to be contained in the catalyst in an amount of 0.1 to 20
wt %, and particularly 1 to 15 wt %, and especially 5 to 12 wt %,
as the total metal weight. A compound of phosphorous and/or boron
(usually in the form of an oxide) can be supported on the catalyst
or added to the catalyst in an amount of 0.1 to 20 wt %, and
particularly 0.2 to 5 wt %, as the element weight, and this
increases the catalyst activity.
[0025] Supporting, kneading, or another such method can be employed
as the method for supporting the hydrogenation active metal
components on the catalyst. Any commonly used impregnation method,
such as pore filling, heating impregnation, vacuum impregnation,
dipping, or another such known means can be used as the method for
supporting the hydrogenation active metal components. After
impregnation with the metal components, it is preferable to dry the
catalyst for 10 minutes to 24 hours at a temperature of 80 to
200.degree. C., and calcine it for 15 minutes to 10 hours at 400 to
600.degree. C., and particularly 450 to 550.degree. C. The kneading
method may involve adding the hydrogenation active metal components
to the raw material powder ahead of time, or mixing and kneading
them along with the raw material powder.
[0026] As to the pore structure of the hydrorefining catalyst, it
is preferable for the pore volume to be at least 0.4 cm.sup.3/g,
and particularly 0.5 to 1.1 cm.sup.3/g, and especially 0.6 to 1.0
cm.sup.3/g. The pore volume referred to here can be measured from
the amount of nitrogen gas adsorbed (calculated as a liquid) at a
relative pressure of 0.967 in a nitrogen gas removal process. The
median pore diameter in a pore diameter distribution of 2 to 60 nm
is preferably 6 to 30 nm (or 6 to 20 nm), and particularly 8 to 15
nm, and especially 8 to 12 nm, and the specific surface area is
preferably 100 to 350 m.sup.2/g, and particularly 150 to 250
m.sup.2/g. The median pore diameter can be measured as the pore
diameter at which the cumulative pore volume from the larger pore
volume side is half the pore volume (V/2), from the relationship
between pore diameter and pore volume calculated by the BJH method
using as the pore volume (V) the volume measured from the amount of
nitrogen gas adsorbed (calculated as a liquid) at a relative
pressure of 0.967 in a nitrogen gas removal process. The pore size
distribution at a pore diameter of approximately 2 to 60 nm can be
measured by nitrogen adsorption method. The BJH method is disclosed
in the Journal of the American Chemical Society, Vol. 73, p. 373
(1951). Mercury intrusion porosimetry method can be used for pore
volumes that exceed the measurement range of the nitrogen
adsorption method. Measurement by mercury intrusion porosimetry
method was conducted at a mercury contact angle of 140.degree. and
a surface tension of 480 dyne/cm, within a pressure range of 2 to
4225 kg/cm.sup.2 (30.4 to 60,000 psia).
[0027] Hydrorefining is a treatment in which a hydrocarbon oil is
brought into contact with a hydrorefining catalyst along with
hydrogen so as to reduce the amount of sulfur and other impurities
contained in the oil. At least 50%, and particularly 70% or more,
of the sulfur contained in a feed oil is usually removed by a
hydrorefining treatment. Preferred reaction conditions include a
reaction temperature of 300 to 450.degree. C., a hydrogen partial
pressure of 3 to 25 MPa, a liquid space velocity of 0.1 to 10
hr.sup.-1, and a hydrogen/oil ratio (the ratio of hydrogen to
hydrocarbon) of 100 to 4000 L/L. Even better is a reaction
temperature of 320 to 430.degree. C., a hydrogen partial pressure
of 8 to 20 MPa, a liquid space velocity of 0.15 to 2.0 hr.sup.-1,
and a hydrogen/oil ratio of 300 to 1500 L/L. Examples of
hydrorefining include hydrodesulfurization, hydrodenitrogenation,
and hydrodemetalization.
[0028] The heavy oil that is the subject of hydrorefining has as
its main component a fraction with a boiling point of at least
350.degree. C., and preferably contains at least 30%, and
particularly at least 50%, a fraction with a boiling point of at
least 350.degree. C. Examples of such heavy oils include various
heavy fractions and residual oils obtained by the atmospheric
distillation or vacuum distillation of crude oil, tar sand, shale
oil, coal liquefaction oil, or the like, as well as these heavy
oils that have undergone a treatment such as cracking,
isomerization, reformation, or solvent extraction.
Regenerated Powder
[0029] With the present invention, a catalyst powder (hereinafter
also referred to as a regenerated powder) is obtained by
pulverizing a spent catalyst. The spent catalyst can be pulverized
by using a known apparatus such as a ball mill, roller mill, jet
mill, or pulverizer. This pulverization is performed such that the
regenerated powder obtained by the pulverization of the spent
catalyst will have an average particle diameter of 800 .mu.m or
less, and preferably 50 to 600 .mu.m, and even more preferably 100
to 500 .mu.m. "Average particle diameter" as used here is the
median diameter measured by a standard wet laser light scattering
method.
[0030] The regenerated powder is fractionated according to its
metal content, and particularly its vanadium and nickel content. A
regenerated catalyst (discussed below) is manufactured using
regenerated powder that has a lower content of vanadium and nickel
than before fractionation. The metal is preferably recovered from
regenerated powder that has a higher content of vanadium and nickel
than before fractionation. Fractionation according to the metal
content can be performed using the specific gravity of the
regenerated powder, its interaction with magnetic force, its shape
or color, its interaction with solvents, and so forth. Specific
examples of fractionation methods include floatation sorting, shape
sorting, color sorting, fluid classification, thin flow sorting,
magnetic separation, and vibratory sieving.
[0031] It is particularly favorable to employ fractionation by
particle diameter, and more specifically, fractionation with a
sieve having a mesh size of 100 to 400 .mu.m, or fractionation by
magnetic force, and more specifically, fractionation by magnetic
flux density of 2000 to 50,000 gauss, and particularly 5000 to
20,000 gauss. The magnetic separation apparatus can be a high-slope
magnetic separator, a drum-type magnetic separator, or the like.
When magnetic separation is performed, it is preferable for the
regenerated powder to contain iron in an amount of 0.3 to 10 wt %,
and particularly 0.5 to 5 wt %. This is because if iron is
contained in the heavy oil being subjected to hydrorefining, it
will build up over the course of the hydrorefining, and if it is
not contained in the heavy oil, a treatment should be performed to
build up the iron, such as the hydrorefining of a heavy oil
containing iron. Magnetic separation will be easier if the iron is
present in the form of an oxide (ferrite), so it is preferable to
perform a heat treatment in an oxidative atmosphere prior to the
magnetic separation step.
[0032] A combination of the above separation methods may also be
employed. This fractionation yields a regenerated powder with a
relatively low metal content.
[0033] A pretreatment can also be performed to remove hydrocarbons,
coke, metals, or the like contained in the spent catalyst either
before or after the pulverization of the spent catalyst. In
particular, to remove hydrocarbons and coke, it is preferable to
perform a heat treatment in an inert atmosphere such as nitrogen,
and then perform a heat treatment in an oxidative atmosphere such
as air or in a mixed gas of air and a combustion gas. This heat
treatment should be performed for 1 to 12 hours (or 1 to 24 hours),
and particularly 2 to 6 hours (or 2 to 12 hours), at a temperature
of 300 to 600.degree. C. (or 250 to 600.degree. C.), and
particularly 350 to 550.degree. C. (or 300 to 550.degree. C.)
Metal Recovery
[0034] Vanadium and nickel can be recovered from a regenerated
powder with a relatively high metal content. This recovery can be
performed by oxidizing roasting, autoclaving, soda roasting,
complete dissolution, or another such method. The metal content of
the separated spent catalyst powder is 1.2 to 5 times, and
particularly 1.5 to 3 times, the metal content of the original
spent catalyst, so the metal can be recovered more efficiently.
Manufacturing the Regenerated Catalyst
[0035] A regenerated catalyst is manufactured by forming the
above-mentioned regenerated powder. For the purposes of this
forming, the average particle diameter of the regenerated powder
should be 300 .mu.m or less, and particularly 200 .mu.m or less,
with 1 to 150 .mu.m being especially good, and 5 to 100 .mu.m even
better. If the average particle diameter of the regenerated powder
is above this preferable range, the powder is pulverized as needed
using a known apparatus such as a ball mill, roller mill, jet mill,
or pulverizer.
[0036] The regenerated powder is preferably a powder whose pore
volume is at least 0.4 cm.sup.3/g and whose average particle
diameter is at least 1 .mu.m. If the pore volume of the regenerated
powder is less than 0.3 cm.sup.3/g, or preferably 0.4 cm.sup.3/g,
the volume of pores with a diameter of 50 nm or less in the
regenerated catalyst will be low, so the amount of metal build-up
will be small. If the average particle diameter is less than 1
.mu.m, the volume of pores with a diameter of 50 to 2000 nm in the
regenerated catalyst will be low, so demetalization activity will
decrease. If the average particle diameter is over 300 .mu.m, the
volume of pores with a diameter of over 2000 nm in the regenerated
catalyst will be high, so the mechanical strength of the
regenerated catalyst will decrease.
[0037] There are no particular restrictions on the method for
forming the regenerated powder, but an example is to add water, an
organic solvent, or the like to the regenerated powder to produce a
mixture in the form of a paste or clay. This forming can be
performed by extrusion forming, press forming, coating of a worked
sheet, or the like. A regenerated catalyst can be obtained by
drying and, if needed, calcination after the forming. A regenerated
powder in the form of a gel or slurry can be formed into beads by
being dispersed and dried in a dry gas (such as spray drying).
Further, a regenerated powder in the form of a gel or slurry also
can be formed into beads in a liquid. Forming methods in which the
regenerated powder is formed directly include a method in which a
forming auxiliary is added as needed to the regenerated powder and
press forming is performed in a tablet-making machine, and a method
in which the forming involves rolling granulation.
[0038] The mixing of the regenerated powder and liquid during
forming can be accomplished with any mixer, kneader, or the like
commonly used in catalyst preparation. One favorable method
involves adding water to the above-mentioned regenerated powder and
then mixing with agitator blades. Normally, water is added as the
liquid here, but this liquid may instead be an alcohol, a ketone,
or another organic compound. Nitric acid, acetic acid, formic acid,
and other such acids, ammonia and other such bases, organic
compounds, surfactants, active components, and so forth may also be
added and mixed, and it is particularly favorable to add a forming
auxiliary composed of an organic compound such as water-soluble
cellulose ether in an amount of 0.1 to 7 wt %, and particularly 0.2
to 5 wt %, and especially 0.5 to 3 wt %, with respect to the
regenerated powder. As to other materials besides the regenerated
powder, pseudo-boehmite powder and other hydrous alumina powders or
the like can also be added in order to increase strength, but it is
preferable for the regenerated powder to be the main component, and
for the proportion of the regenerated catalyst weight accounted for
by the regenerated powder to be at least 70 wt %, and particularly
at least 80 wt %, and especially at least 95 wt %.
[0039] The material can be easily formed into pellets, a honeycomb
shape, or another shape by using a plunger-type extruder, a
screw-type extruder, or another such apparatus. The material is
usually formed into beads or hollow or solid cylinders with a
diameter of 0.5 to 6 mm, or into a shape such as columns with a
trilobe or quadrilobe cross section. After forming, the product is
dried between normal temperature and 150.degree. C., and preferably
between 100 and 140.degree. C., after which it is calcined for at
least 0.5 hour at 350 to 900.degree. C. (or 350 to 700.degree. C.),
and preferably for 0.5 to 5 hours at 400 to 850.degree. C. (or 400
to 650.degree. C.).
[0040] Because the hydrogenation active metal components supported
by the spent catalyst end up being contained in this regenerated
catalyst, adequate catalyst activity will be exhibited even without
hydrogenation active metal being supported during the manufacture
of the regenerated catalyst. If needed, hydrogenation active metal
components and phosphorus and/or boron can also be supported. The
metal components and support method in this case are the same as
with a hydrorefining catalyst.
[0041] As to the pore state of the regenerated catalyst thus
obtained, it is preferable for the pore volume to be at least 0.15
cm.sup.3/g, and particularly 0.20 cm.sup.3/g, for pores with a
diameter of 50 to 2000 nm; for the pore volume to be at least 0.10
cm.sup.3/g, and particularly at least 0.15 cm.sup.3/g, for pores
with a diameter of 50 to 1000 nm; and for the pore volume to be at
least 0.1 cm.sup.3/g, and particularly 0.05 cm.sup.3/g, for pores
with a diameter of 2000 nm or more. These pore volumes for pores
with a diameter of 50 nm or more can be measured by mercury
intrusion porosimetry method at a mercury contact angle of
140.degree. and a surface tension of 480 dyn/cm within a pressure
range of 2 to 4225 kg/cm.sup.2. The median pore diameter in a pore
diameter distribution of 2 to 60 nm is preferably 6 to 20 nm, and
particularly 8 to 15 nm, and especially 8 to 10 nm, and the
specific surface area is preferably 100 to 350 m.sup.2/g, and
particularly 150 to 200 m.sup.2/g. The median pore diameter can be
measured by nitrogen adsorption method, and the pore volume for
pores with a diameter of 50 nm or less can be measured from the
amount of nitrogen gas adsorbed (calculated as a liquid) at a
relative pressure of 0.967 in a nitrogen gas removal process, using
the nitrogen adsorption method. The total pore volume, which is the
sum of the pore volume for pores with a diameter of 50 nm or less
and the pore volume for pores with a diameter of 50 nm or more, is
preferably at least 0.5 cm.sup.3/g, and particularly at least 0.6
to 1.1 cm.sup.3/g.
[0042] The regenerated catalyst preferably contains molybdenum
and/or tungsten, and nickel and/or cobalt. Since vanadium remains
in the regenerated powder, this vanadium ends up being contained in
the regenerated catalyst as well. The molybdenum and/or tungsten
content is 1 to 20 wt %, and preferably 2 to 10 wt %, the nickel
and/or cobalt content is 0.5 to 10 wt %, and preferably 1 to 5 wt
%, and the vanadium content is 0.2 to 10 wt %, and preferably 0.5
to 5 wt %.
[0043] The distribution of metal components within the catalyst
particles is substantially uniform in this catalyst. More
specifically, the fact that the distribution of metal components is
substantially uniform can be confirmed by the following method. In
a cross section of the catalyst particles (pellets), a plurality of
measurement points are determined on a straight line from the outer
surface of the catalyst to the center of the catalyst, and the
metal component concentration is measured at each of these
measurement points (line analysis). When a distance from the outer
surface to the center of the catalyst is R, a region between the
center of the catalyst and points which lies R/2 away from the
center is called herein as "an inner portion" of the catalyst while
a region between the points and the outer surface is called herein
as an "outer portion" of the catalyst. Whether or not the
distribution of metal components is uniform can be ascertained from
a ratio of an average value of the metal component concentration
(content) at the measuring points in the outer portion and an
average value of the metal component concentration at the measuring
points in the inner portion. If this value is 1, then the
distribution of the metal components can be considered to be
completely uniform. In the present invention, it is preferable for
the value to be 0.8 to 1.2, and particularly from 0.9 to 1.1, and
if it is, the distribution of metal components in the catalyst
particles can be considered to be substantially uniform.
[0044] The phrase "center of the catalyst" as used in this
specification refers to a point or a collection of points included
in the catalyst and farthest away from the outer surface of the
catalyst. When the catalyst approximates a shape of rotational
symmetry, the phrase "center of the catalyst" refers to a point or
a collection of points included in the catalyst and farthest away
from the outer surface of the catalyst in a cross section
perpendicular to the axis of symmetry. For example, when the
catalyst particles are spherical, the center of the catalyst
indicates the center of the sphere. When the catalyst is in the
form of cylinders, the center of the catalyst means a collection of
points that lies along the rotation axis of the cylinder and is
farthest away from the outer surface. When the catalyst is in the
tubular form, the center of the catalyst means a collection of
points that lies along the center axis of the tube and is farthest
away from the outer surface. If the catalyst is in a trilobe or
quadrilobe configuration, the point farthest away from the outer
surface will vary with the extent of overlap in the three or four
lobes. Specifically, if there is little overlap in the three or
four lobes, the point farthest away from the outer surface will be
the center position of each of the lobes, but if there is much
overlap in the three or four lobes, the point farthest away from
the outer surface will be located on the rotational axis of the
trilobe or quadrilobe catalyst. When the catalyst has a shape
having an odd number of lobes such as trilobe and the center of the
catalyst is located on the rotational axis, there may be a case
that a length of one straight line from one point on the outer
surface of the catalyst to the center of the catalyst is different
from a length of the other straight line from the other point,
which is opposed to the one point with respect to the center point,
on the outer surface of the catalyst to the center of the catalyst.
In such a case, the inner portion and the outer portion are defined
on the basis of the different lengths between the one straight line
and the other straight line.
[0045] Any analytical method suited to the quantitative analysis of
elements included in a microregion can be used for the line
analysis of the metal component concentration discussed above. For
example, EPMA, Auger electron spectroscopy, or secondary ion mass
spectrometry (SIMS) can be used. If the catalyst particles
(pellets) have no hollow portions and approximate a shape of
rotational symmetry, then the cross section to be analyzed is one
that is perpendicular to this axis of symmetry, with the axis of
symmetry becoming the center of the cross section.
Hydrodemetalization
[0046] The above-mentioned regenerated catalyst can be used to
advantage as a catalyst in the hydrorefining, and particularly the
hydrodemetalization, of heavy oils. Hydrodemetalization is a
treatment in which a heavy oil containing vanadium and nickel in a
combined amount of at least 45 ppm (as metal elements) is brought
into contact with a catalyst along with hydrogen so that the metal
content in the heavy oil is reduced. The allowable amount of metal
build-up in the regenerated catalyst is 30 wt % or more, and
particularly 50 to 150 wt %. The allowable amount of metal build-up
is the amount of build-up of vanadium and nickel at the point when
metal components have built up in the catalyst through
hydrorefining and the activity has dropped so low that the vanadium
and nickel demetalization rate is 50%, and is defined as the weight
of vanadium and nickel metal elements built up versus the initial
catalyst weight.
[0047] Favorable reaction conditions for hydrodemetalization
include a reaction temperature of 300 to 450.degree. C., a hydrogen
partial pressure of 3 to 25 MPa, a liquid space velocity of 0.1 to
10 hr.sup.-1, and a hydrogen/oil ratio of 100 to 4000 L/L, and
preferably a reaction temperature of 320 to 430.degree. C., a
hydrogen partial pressure of 8 to 25 MPa, a liquid space velocity
of 0.15 to 2.0 hr.sup.-1, and a hydrogen/oil ratio of 300 to 1500
L/L. A fixed bed catalyst layer is usually preferable for the
reactor, but a mobile bed or the like can also be used.
Hydrodenitrogenation and hydrodesulfurization may also proceed
concomitantly during the hydrodemetalization. The heavy oil that is
subjected to hydrodemetalization is a hydrocarbon oil whose main
component is a fraction with a boiling point of at least
350.degree. C., and preferably the fraction with a boiling point of
at least 350.degree. C. is contained in an amount of at least 50%,
and particularly at least 70%. It is also possible to perform
hydrodemetalization on a heavy oil containing 100 ppm or more, or
even 300 ppm or more, vanadium and nickel (as the combined amount
of metal elements).
Recovery of Metal
[0048] Vanadium and nickel are recovered from a demetalized spent
catalyst that has undergone the above-mentioned demetalization
treatment to build up the vanadium and nickel to at least 20 wt %,
and preferably at least 30 wt %, as the combined metal weight with
respect to the weight of the regenerated catalyst at the start of
the demetalization reaction. This recovery can be performed by
oxidizing roasting, autoclaving, soda roasting, complete
dissolution, or another such method.
EXAMPLES
[0049] The present invention will now be described through
examples, but the present invention should not be construed as
being limited by these examples.
Desulfurization Catalyst
[0050] Pseudo-boehmite powder was kneaded and formed into the form
of cylinders ( 1/12 inch) and quadrilobe columns ( 1/22 inch).
These were each calcined for 1 hour at 600.degree. C. to produce
.gamma.-alumina carriers, which were impregnated in an ammonium
molybdate aqueous solution and a nickel nitrate aqueous solution,
respectively, and then dried for 20 hours at 130.degree. C., after
which these products were calcined for 0.5 hour at 450.degree. C.
to obtain two types of desulfurization catalyst of different
shapes. Table 1 lists the composition and properties of the
resulting desulfurization catalyst comprising 1/12-inch cylinders
(hereinafter referred to as the cylindrical desulfurization
catalyst) and the desulfurization catalyst comprising 1/22-inch
quadrilobe columns (hereinafter referred to as the quadrilobe
desulfurization catalyst). The specific surface area referred to
here was measured by BET method using the adsorption of nitrogen,
and the pore volume was measured from the amount of nitrogen gas
adsorbed (calculated as a liquid) at a relative pressure of 0.967
in a nitrogen gas removal process. This pore volume corresponds to
the volume of pores with a diameter of 50 nm or less.
TABLE-US-00001 TABLE 1 Cylindrical Quadrilobe desulfurization
desulfurization catalyst catalyst Fresh Molybdenum 8.0 8.2 catalyst
(metal t %) prior to Nickel 2.2 2.3 operation (metal wt %) Alumina
85 85 (wt %) Specific 232 231 surface area (m.sup.2/g) Pore volume
0.61 0.60 (cm.sup.3/g) Median pore 9.1 8.9 diameter (nm) Amount of
Nickel 4.5 2.9 build-up (metal wt %) on spent Vanadium 10.4 7.5
catalyst (metal wt %) Iron 1.9 2.1 (metal wt %)
Hydrodesulfurization
[0051] The above desulfurization catalyst was packed into the
reactor of a heavy oil desulfurization apparatus installed at the
Mizushima Refinery of Japan Energy Corporation. The reaction column
of the heavy oil desulfurization apparatus was divided into an
upstream catalyst layer (36 vol %) and a downstream catalyst layer
(64 vol %), and the above-mentioned two types of desulfurization
catalyst were packed into the downstream catalyst layer. After
packing, the apparatus was operated for 397 days using a feed oil
with the average properties shown in Table 2, under the reaction
conditions shown in Table 3. Table 4 shows the conversion rate at
the start of run, the average throughout the operation period, and
the end of run. TABLE-US-00002 TABLE 2 Vacuum distillation residue
from Middle-Eastern Feed oil crude oil 10% distillate temperature
(.degree. C.) 490 30% distillate temperature (.degree. C.) 554 50%
distillate temperature (.degree. C.) 629 Specific gravity 1.045
Sulfur (wt %) 5.13 Vanadium (wt ppm) 110 Nickel (wt ppm) 38 Iron
(wt ppm) 11
[0052] TABLE-US-00003 TABLE 3 Average reaction pressure (MPa) 13.8
Average hydrogen/oil ratio (L/L) 1050 Average reaction temperature
(.degree. C.) 379 Average liquid space velocity in upstream 0.36
catalyst layer (hr.sup.-1) Average liquid space velocity in
downstream 0.20 catalyst layer (hr.sup.-1)
[0053] TABLE-US-00004 TABLE 4 At start At the end of run Average of
run Desulfurization 87 83 73 rate (%) Vanadium 79 76 66 removal
rate (%) Nickel removal 65 63 52 rate (%) Reaction 366 379 400
temperature (.degree. C.)
[0054] The desulfurization catalyst was recovered as spent catalyst
upon completion of the above operation, Soxhlet extraction was
performed, and this was followed by elemental analysis to measure
the amount of metal build-up. These results are shown in Table 1.
The amounts of build-up of the various metals were determined while
assuming that the fresh catalyst prior to operation consisted of
Al.sub.2O.sub.3, MoO.sub.3, and NiO, the total weight of these
compounds was the weight of the fresh catalyst, and the ratio
between aluminum, molybdenum, and nickel contained in the fresh
catalyst was preserved in the spent catalyst. The fresh catalyst
weight with respect to the spent catalyst was determined from the
ratio of Al.sub.2O.sub.3, MoO.sub.3, and NiO in the fresh catalyst
and the results of analysis of the elemental aluminum weight in the
spent catalyst. Since nickel was also contained in the fresh
catalyst, the remainder of subtracting the weight of elemental
nickel contained in the fresh catalyst from the weight contained in
spent catalyst was termed the nickel build-up amount.
[0055] The process of regenerating the resulting spent catalyst
will now be described through reference to the flow chart in FIG.
1.
Calcination of Spent Catalyst (S1)
[0056] The recovered spent catalyst was heat treated in an
atmosphere furnace for 2-3 hours at 350.degree. C. under a nitrogen
gas flow to remove the oil component. After this, calcination was
performed for 5-15 hours at 500.degree. C. under an air flow to
remove part of the coke near the surface of the spent catalyst and
to partially oxidize the metal sulfides. Calcination has to be
continued for at least 20 hours in order to completely remove the
coke or to completely oxidize the metal sulfides.
Pulverization of Spent Catalyst (S2)
[0057] As shown in Table 5, the calcined spent catalyst was
continuously pulverized at 3000 rpm in a cutter mill (model MF10
Basic S1 by Ika Japan Co. Ltd.) in experiment numbers F20, F21,
F22, F24, F28, and F32. Here, the aperture of the discharge outlet
of the cutter mill was adjusted so that the pulverized spent
catalyst would be obtained with an average particle diameter of 200
to 450 .mu.m. The average particle diameter in this example was
measured in wet manner, using a MicroTrac particle size
distribution analyzer made by Nikkiso. In this wet manner, the
sample is dispersed in water and irradiated with laser light, and
particle size analysis is conducted by means of the
forward-scattered light.
Sieving Separation (S3)
[0058] In experiment number F19, the calcined spent catalyst was
not pulverized, but was separated with a sieve having a mesh size
of 500 .mu.m into plus sieve used as the regenerated catalyst
sample and minus sieve used as the metal recovery sample. In
experiment number F24, spent catalyst, which had been pulverized by
a cutter mill, was separated with a sieve having a mesh size of 300
.mu.m into plus sieve used as the regenerated catalyst sample and
minus sieve used as the metal recovery sample. It is believed that,
since the metal content attached or deposited on the outer surface
of the spent catalyst is easy to pulverize, particles having higher
content of metal components are collected, passing through the
sieve.
Magnetic Separation
[0059] In experiment numbers F20, F21, F20, F28, and F32, a rod
magnet with a surface flux density of 10,000 G made by Nippon
Magnetics Inc. was used to separate the pulverized spent catalyst
into magnetic and non-magnetic portions. The magnetic portion was
used as the metal recovery sample, and the non-magnetic portion was
used as the regenerated catalyst sample. TABLE-US-00005 TABLE 5
Cylindrical Quadrilobe Catalyst desulfurization desulfurization
Experiment catalyst catalyst No. F20 F21 F24 F28 F19 F22 F32
Pulverization C/M* C/M* C/M* C/M* None C/M* C/M* Separation M/
M/F** sieve M/F** sieve M/F** M/F** method F** *Cutter mill
**Magnetic force
Re-Calcination (S4)
[0060] The metal recovery sample and the regenerated catalyst
sample from which the pulverized spent catalyst had been separated
were put back in the atmosphere furnace and calcined for 5-10 hours
at 500.degree. C. under an air flow to remove the coke and oxidize
the metal sulfides. As shown in Tables 6 and 7, after this second
calcination the metal recovery sample contained more vanadium and
iron than the regenerated catalyst sample, while the regenerated
catalyst sample had a larger specific surface area and pore volume
and contained more molybdenum than the metal recovery sample. It
can be seen that the regenerated catalyst sample in experiment
number F19, which was not pulverized, had a higher content of
vanadium and so forth than the other samples, and had a smaller
specific surface area and pore volume. TABLE-US-00006 TABLE 6
Regenerated catalyst sample Cylindrical Quadrilobe desulfurization
catalyst desulfurization catalyst Experiment No. F20 F21 F24 F28
F19 F22 F32 Separation 61 63 67 61 67 59 76 rate (wt %) Vanadium
(wt %) 3.9 4.2 5.1 4.8 6.7 5.2 4.8 Nickel (wt %) 3.3 3.5 3.6 3.6
4.1 4.2 4.0 Molybdenum (wt %) 7.2 6.3 6.3 6.8 5.8 6.0 6.5 Iron (wt
%) 0.3 0.3 1.4 0.3 0.8 0.3 0.2 Specific surface area 176 174 153
165 120 151 159 (m.sup.2/g) Pore volume 0.53 0.51 0.45 0.49 0.37
0.45 0.46 (cm.sup.3/g) Median pore 9.9 9.5 9.8 9.8 10.0 9.9 9.7
diameter (nm)
[0061] TABLE-US-00007 TABLE 7 Metal recovery sample Cylindrical
Quadrilobe desulfurization desulfurization Experiment catalyst
catalyst No. F20 F21 F24 F28 F19 F22 F32 Separation 39 37 33 39 33
41 24 rate (wt %) Vanadium 7.7 7.7 6.8 6.9 7.5 8.1 7.5 (wt %)
Nickel 3.4 3.9 3.6 3.5 3.9 4.4 4.3 (wt %) Molybdenum 4.6 5.1 5.1
4.9 5.0 5.2 5.7 (wt %) Iron (wt %) 6.0 5.7 6.1 7.3 3.0 2.3 1.8
Specific 99 101 112 93 80 102 105 surface area (m.sup.2/g) Pore
volume 0.29 0.30 0.34 0.28 0.25 0.31 0.31 (cm.sup.3/g) Median pore
9.5 9.5 9.7 9.9 10.3 9.8 9.9 diameter (nm)
Preparation of Regenerated Catalyst (S5-S8)
[0062] Using a ball mill, regenerated catalyst sample F28 was
pulverized to an average particle diameter of 15 .mu.m (S5), water
was added to and mixed with 650 g of this pulverized catalyst and
19 g of water-soluble cellulose ether, and this mixture was formed
into 1/20-inch quadrilobe columns (four lobes in axial symmetry and
having minor and major axes perpendicular to each other) (S6). This
product was dried for 15 hours at 130.degree. C. (S7) and then
calcined for 1 hour at 500.degree. C. under an air flow (S8), which
yielded a regenerated catalyst. The pore volume of this regenerated
catalyst was measured by mercury intrusion porosimetry method,
which revealed that the volume of pores with a diameter of 50 to
1000 nm was 0.16 cm.sup.3/g, the volume of pores with a diameter of
50 to 2000 nm was 0.21 cm.sup.3/g, and the volume of pores with a
diameter over 2000 nm was 0.01 cm.sup.3/g. The pore structure of
this regenerated catalyst was measured by nitrogen adsorption
method, which revealed that the specific surface area was 163
m.sup.2/g, the volume of pores under 50 nm was 0.45 cm.sup.3/g, and
the median pore diameter was 9.6 nm. Since the water-soluble
cellulose ether was removed by oxidation in the calcination step,
the regenerated catalyst substantially consisted of just the
regenerated catalyst sample. The average particle diameter is the
median diameter as measured by wet laser light scattering.
Distribution of Metal Components in Regenerated Catalyst
[0063] The distribution of metal component concentrations in the
regenerated catalyst was determined by the line analysis discussed
above. This line analysis was conducted using EPMA at an
acceleration voltage of 20 kV, a probe current of 0.1 uA, a beam
diameter of 50 .mu.m, a step width of 50 .mu.m, and a measurement
duration of 1000 msec/point. The samples consisted of three pellets
(sample Nos. 1 to 3) of the quadrilobe regenerated catalyst
obtained as above (the catalyst obtained from F28). Each of three
samples was embedded in epoxy resin, and was polished to generate a
cross sectional plane perpendicular to the rotational axis. Then,
the plane was surface processed by vapor-depositing carbon on the
plane. The beam was scanned over a straight line which has the
longest distance between the center of the catalyst on the
rotational axis and a point on the outer surface of the four lobes
of each sample. These results are given in Table 8. As shown in
Table 8, in each of the samples, a ratio of an average
concentration of the metal component in the measuring points in the
inner portion of the catalyst to that in the measuring points in
the outer portion is in the range of 0.9 to 1.1. This tells us that
the molybdenum, nickel, and vanadium were uniformly distributed
throughout the regenerated catalyst. TABLE-US-00008 TABLE 8 Average
Average Concentration Concentration of Outer of Inner Outer
Portion/ Metal Portion Portion Inner Sample Component (count)
(count) Portion No. 1 Mo 1737 1611 1.08 Ni 3845 3605 1.07 V 4691
5205 0.90 No. 2 Mo 1661 1756 0.95 Ni 4117 4054 1.02 V 4737 4768
0.99 No. 3 Mo 1556 1439 1.08 Ni 3329 3104 1.07 V 4156 4449 0.93
Hydrodemetalization
[0064] The regenerated catalyst was packed in an amount of 100
cm.sup.3 in a fixed bed reactor (inside diameter: 25 mm, length:
1000 mm), and a hydrodemetalization reaction was conducted for 480
hours using the Boscan crude oil shown in Table 9 and under the
hydrotreating conditions given in Table 10. At the start of the
reaction the vanadium removal rate was 76% and the nickel removal
rate was 64%, and at the end of the reaction the vanadium removal
rate was 61% and the nickel removal rate was 52%, confirming that
the regenerated catalyst had high demetalization activity. Upon
completion of the reaction, the regenerated catalyst was recovered
as a spent catalyst, Soxhlet extraction was performed, and this was
followed by elemental analysis, which revealed that there had been
a build-up of 40.3 wt % vanadium and 3.3 wt % nickel, as the metal
element weight with respect to the weight of the regenerated
catalyst. For the amounts of build-up of the metals, the remainder
of subtracting the weight of each metal contained in the
regenerated catalyst prior to operation from the weight of each
metal present in the spent catalyst after the reaction was
indicated as a proportion with respect to the regenerated catalyst
prior to operation. The metal build-up volume of the regenerated
catalyst was 75 wt %. TABLE-US-00009 TABLE 9 Feed oil Boscan crude
oil 10% distillate temperature (.degree. C.) 314 30% distillate
temperature (.degree. C.) 476 50% distillate temperature (.degree.
C.) 576 Specific gravity 0.998 Sulfur (wt %) 4.62 Vanadium (wt ppm)
1197 Nickel (wt ppm) 116
[0065] TABLE-US-00010 TABLE 10 Reaction pressure (MPa) 14.0
Hydrogen/oil ratio (L/L) 670 Reaction temperature (.degree. C.) 390
Liquid space velocity in 1.0 upstream catalyst layer
(hr.sup.-1)
Recovery of Metals
[0066] Upon completion of the reaction, the regenerated catalyst
was heat treated in an atmosphere furnace for 1 hour at 350.degree.
C. under a nitrogen gas flow to remove the oil component, and then
roasting for 4 hours at 450.degree. C. in an air flow, which
oxidized the metal sulfides and removed the coke. Ion exchange
water was added to the roasted catalyst, and this was heated to
80.degree. C., after which sulfuric acid was added to bring the pH
to 1, sodium sulfite was added in an amount of 0.8 equivalent with
respect to the vanadium, and the system was stirred for 90 minutes,
after which it was filtered to extract the vanadium, nickel, and
molybdenum. The sediment remaining after extraction was primarily
alumina, and after drying, it was disposed of as a non-combustible.
Metal recovery can also be performed by the same procedure for the
regenerated powder used for metal recovery (SS1).
[0067] With experiment numbers F20, F21, F22, F28, and F32 in this
example, a rod magnet was used to separate the pulverized spent
catalyst into magnetic and non-magnetic portions, but this
separation can also be accomplished with the pulley-type magnetic
separation shown in FIG. 2 (a high magnetic force, pulley-type,
stainless steel separator made by Nippon Magnetics Inc.). As shown
in FIG. 2, the spent catalyst powder 1 is continuously supplied
onto a horizontally rotating belt 2, and conveyed by the rotation
of the belt to a pulley 3 provided at one end. The pulley 3 is made
of a rare earth magnet, and applies a magnetic field of 12,000
gauss to the belt 2. Accordingly, when the belt 2 moves under the
pulley 3, the spent catalyst powder containing a large quantity of
iron is drawn toward the surface of the belt, whereas the spent
catalyst powder containing little iron falls off the belt 2. As a
result, the place where the powder falls is divided into a
high-metal zone 4 and a low-metal zone 5, allowing the magnetic
separation to be accomplished by means of the zones in which the
powder falls.
[0068] With the catalyst manufacturing method of the present
invention, a catalyst with high catalytic activity and with
adequate mechanical strength can be manufactured from a catalyst
that has been used in the hydrorefining of a heavy oil. This is
extremely effective in terms of recycling natural resources. Also,
the use of the metal recovery method of the present invention
allows valuable metals such as vanadium to be recovered from a used
catalyst inexpensively and at a high yield.
* * * * *