U.S. patent application number 10/143108 was filed with the patent office on 2003-03-27 for autothermal reforming catalyst and process of producing fuel gas for fuel cell.
This patent application is currently assigned to NIPPON MITSUBISHI OIL CORPORATION. Invention is credited to Anzai, Iwao, Matsumoto, Takaya.
Application Number | 20030060363 10/143108 |
Document ID | / |
Family ID | 18987848 |
Filed Date | 2003-03-27 |
United States Patent
Application |
20030060363 |
Kind Code |
A1 |
Anzai, Iwao ; et
al. |
March 27, 2003 |
Autothermal reforming catalyst and process of producing fuel gas
for fuel cell
Abstract
Autothermal reforming catalysts comprises ruthenium supported on
a support containing 5 to 40 percent by mass of a cerium oxide or
rare earth element oxide which is composed principally of a cerium
oxide, 60 to 95 percent by mass of an aluminum oxide, and 0 to 10
percent by mass in terms of metal of one or more elements selected
from the group consisting of an alkaline metal and an alkaline
earth metal, the atomic ratio of cerium and rhodium (Ce/Rh) being 1
to 250.
Inventors: |
Anzai, Iwao; (Yokohama-shi,
JP) ; Matsumoto, Takaya; (Yokohama-shi, JP) |
Correspondence
Address: |
AKIN, GUMP, STRAUSS, HAUER & FELD, L.L.P.
ONE COMMERCE SQUARE
2005 MARKET STREET, SUITE 2200
PHILADELPHIA
PA
19103
US
|
Assignee: |
NIPPON MITSUBISHI OIL
CORPORATION
|
Family ID: |
18987848 |
Appl. No.: |
10/143108 |
Filed: |
May 10, 2002 |
Current U.S.
Class: |
502/304 ;
423/651 |
Current CPC
Class: |
C01B 2203/1235 20130101;
C01B 3/326 20130101; C01B 2203/1082 20130101; B01J 35/1019
20130101; C01B 2203/1205 20130101; B01J 35/10 20130101; B01J 23/63
20130101; C01B 2203/0244 20130101; C01B 2203/1217 20130101; C01B
2203/0844 20130101; C01B 2203/066 20130101; C01B 3/40 20130101;
Y02P 20/52 20151101; C01B 2203/1064 20130101 |
Class at
Publication: |
502/304 ;
423/651 |
International
Class: |
C01B 003/26 |
Foreign Application Data
Date |
Code |
Application Number |
May 11, 2001 |
JP |
2001-141381 |
Claims
What is claimed is:
1. An autothermal reforming catalyst which comprises ruthenium
supported on a support containing 5 to 40 percent by mass of a
cerium oxide or rare earth element oxide which is composed
principally of a cerium oxide, 60 to 95 percent by mass of an
aluminum oxide, and 0 to 10 percent by mass in terms of metal of
one or more elements selected from the group consisting of an
alkaline metal and alkaline earth metal, the atomic ratio of cerium
and ruthenium (Ce/Ru) being 1 to 250.
2. The autothermal reforming catalyst according to claim 1 wherein
ruthenium is supported in an amount of 0.1 to 3 percent by mass in
terms of metal based on the catalyst weight on said support.
3. The autothermal reforming catalyst according to claim 1 wherein
said cerium oxide is ceric oxide.
4. The autothermal reforming catalyst according to claim 1 wherein
said rare earth element oxide contains a cerium oxide in an amount
of 50 percent by mass or more.
5. The autothermal reforming catalyst according to claim 1 wherein
said aluminum oxide is alumina or silica-alumina.
6. The autothermal reforming catalyst according to claim 1 wherein
said alkaline metal is potassium or caesium.
7. The autothermal reforming catalyst according to claim 1 wherein
said alkaline earth metal is selected from the group consisting of
magnesium, barium, and calcium.
8. The autothermal reforming catalyst according to claim 1 wherein
said support contains 10 to 35 percent by mass of a cerium oxide or
rare earth element oxide which is composed principally of a cerium
oxide, 65 to 90 percent by mass of an aluminum oxide, and 0.8 to 7
percent by mass in terms of metal of one or more elements selected
from the group consisting of an alkaline metal and an alkaline
earth metal.
9. The autothermal reforming catalyst according to claim 1 wherein
the surface area of said catalyst is 5 to 200 m.sup.2/g.
10. The autothermal reforming catalyst according to claim 1 wherein
the pore volume of said catalyst is 0.05 to 1.0 cm.sup.3/g.
11. A process for producing a fuel gas for a fuel cell which
comprises a step of converting hydrocarbons and/or
oxygen-containing hydrocarbons to a reformed gas which is composed
principally of hydrogen by an autothermal reforming reaction using
the catalyst as defined in claim 1 or 2.
12. The process for producing a fuel gas for a fuel cell according
to claim 11 wherein said autothermal reaction is conducted at a
catalyst bed inlet temperature of 200 to 800.degree. C. and at a
catalyst bed exit temperature of 500 to 1,000.degree. C.
13. The process for producing a fuel gas for a fuel cell according
to claim 11 wherein said autothermal reaction is conducted at a
pressure of atmospheric pressure to 5 MPa.
14. The process for producing a fuel gas for a fuel cell according
to claim 11 wherein the feed stock to be converted to said reformed
gas is selected from the group consisting of methane, ethane,
propane, butane, natural gas, LPG, manufactured gas, gasoline,
naphtha, kerosene, liquid fuels having a boiling point within the
range of those thereof, methanol, ethanol, propanol, and dimethyl
ether.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to an autothermal reforming catalyst.
This invention also relates to a process of producing a fuel gas
for a fuel cell wherein hydrocarbons and/or oxygen-containing
hydrocarbons are converted to a reformed gas which is composed
principally of hydrogen by an autothermal reforming reaction using
such a catalyst.
[0003] 2. Description of the Prior Art
[0004] A known process for producing hydrogen from hydrocarbons or
oxygen-containing hydrocarbons is an autothermal reforming method
which is the combination of an oxidation reaction and a steam
reforming reaction. In this process, hydrocarbons or
nitrogen-containing hydrocarbons, steam, and oxygen or air are
introduced into a reactor, and a part of the hydrocarbons or
oxygen-containing hydrocarbons is subjected to partial or complete
combustion. While the reactor is then heated to a predetermined
temperature with the heat generated by the combustion, the
remaining hydrocarbons or oxygen-containing hydrocarbons are
steam-reformed such that they are converted to a reformed gas which
is composed principally of hydrogen. While a catalyst is charged
into the reactor, it is required to have a combustion activity and
a steam reforming activity.
[0005] Examples of such a catalyst are base metal-based catalysts
such as nickel, copper, iron, and cobalt, and noble metal-based
catalysts such as platinum, rhodium, ruthenium, iridium, and
palladium.
[0006] The base metal-based catalysts are relatively prone to cause
carbon precipitation. Since in order to suppress this, it is
necessary to use materials of the catalyst, i.e., hydrocarbons or
oxygen-containing hydrocarbons with an excess amount of steam,
resulting in a condition where the steam/carbon ratio is high, the
activity is inevitably reduced.
[0007] On the other hand, since the noble metal-based catalysts
hardly cause the precipitation of carbon even under such a
condition that the steam/carbon ratio is low, they have an
advantage that an excess amount of steam is not required and a
reformed gas which is composed principally of hydrogen can be
produced at higher efficiency. However, these catalysts have a
problem that they are expensive.
[0008] While ruthenium is relatively cheap, it is prone to de be
decreased in activity due to volatilization in the case where
oxygen coexists at elevated temperatures such as those at which an
autothermal reforming reaction is conducted.
[0009] Therefor, there has been demanded a cheap catalyst which
hardly cause the carbon to precipitate even under such a condition
that the steam/carbon ratio is low in an autothermal reforming
reaction so as to be able to produce hydrogen at high efficiency
and is excelled in heat resistance under the coexistence of oxygen,
but such a catalysts has not been developed yet.
[0010] In view of the foregoing, an object of the present invention
is to provide a catalyst having a sufficient activity and working
life in an autothermal reforming process with maintaining the
effect of suppressing the carbon to precipitate at a low
steam/carbon ratio and comprising ruthenium which is relatively
inexpensive.
BREIF SUMMARY OF THE INVENTION
[0011] According to the present invention, there is provided an
autothermal reforming catalyst comprising ruthenium supported on a
support comprising 5 to 40 percent by mass of a cerium oxide or
rare earth element oxide which is composed principally of a cerium
oxide, 60 to 95 percent by mass of an aluminum oxide, and 0 to 10
percent by mass in terms of metal of one or more elements selected
from the group consisting of an alkaline metal and an alkaline
earth metal, the atomic ratio of cerium to ruthenium (Ce/Ru) being
from 1 to 250.
[0012] According to the present invention, there is also provided
the autothermal reforming catalyst characterized in that ruthenium
in an amount of 0.1 to 3 percent by mass in terms of metal based on
the weight of the catalyst is supported.
[0013] Furthermore, according to the present invention, there is
provided a process of producing a fuel gas for a fuel cell wherein
hydrocarbons and/or oxygen-containing hydrocarbons are converted to
a reformed gas which is composed principally of hydrogen by an
autothermal reforming reaction using the catalyst.
DETAILED DESCRIPTION OF THE INVENTION
[0014] First of all, the support used in the present invention is
described.
[0015] The support used in the present invention characteristically
comprises 5 to 40 percent by mass of a cerium oxide or rare earth
element oxide which is composed principally of a cerium oxide, 60
to 95 percent by mass of an aluminum oxide, and 0 to 10 percent by
mass in terms of metal of one or more elements selected from the
group consisting of an alkaline metal and an alkaline earth
metal.
[0016] No particular limitation is imposed on the cerium oxide used
in the present invention. However, ceric oxide generally referred
to as ceria is preferred.
[0017] No particular limitation is imposed on the method of
preparing the cerium oxide which, therefore, may be prepared using
cerium nitrate (Ce(NO.sub.3).sub.3.multidot.6H.sub.20,
Ce(NO.sub.3).sub.4), cerium chloride
(CeCl.sub.3.multidot.nH.sub.2O), cerium hydroxide (CeOH.sub.3,
CeOH.sub.4.multidot.H.sub.2O), cerium carbonate
(Ce.sub.2(CO.sub.3).sub.3- .multidot.8H.sub.2O,
Ce.sub.2(CO.sub.3).sub.3.multidot.5H.sub.2O), cerium oxalate,
cerium oxalate (IV) ammonium, or cerium chloride as the starting
material in a conventional manner such as calcination in the
air.
[0018] The rare earth element oxide which is composed principally
of a cerium oxide may be prepared from the salts of a mixed rare
earth element which is composed principally of cerium.
[0019] The rare earth metal which is composed principally of a
cerium oxide contains a cerium oxide in an amount of generally 50
percent by mass or more, preferably 60 percent by mass or more, and
more preferably 70 percent by mass or more.
[0020] Examples of the rare earth element oxide are oxides of each
element such as scandium, yttrium, lanthanum, protheodymium,
neodymium, promethium, samarium, europium, gadolinium, terbium,
dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.
Among these, preferred are oxides of yttrium, lanthanum, and
neodymium, and more preferred are oxides of lanthanum. No
particular limitation is imposed on the form of their
crystallinity, and they may, therefore, have any type of
crystallinity form.
[0021] The aluminum oxide used in the present invention includes,
other than alumina, double oxides of aluminum and other element
such as silicon, copper, iron, and titanium. Typical examples of
such double oxides are silica alumina and the like.
[0022] Particularly preferred for the aluminum oxide is alumina. No
particular limitation is imposed on alumina which may, therefore,
have any type of crystallinity form such as .alpha., .beta.,
.gamma., .eta., .theta., .kappa., and .chi.. Particularly preferred
is .gamma.-type alumina. There may also be used alumina hydrates
such as boehmite, bialite, and gibbsite.
[0023] No particular limitation is imposed on silica alumina which
may, therefore, be in any type of crystallinity form. Needless to
mention, an aluminum oxide even containing a small amount of
impurities can be used without hindrance.
[0024] Examples of the alkaline metal are lithium, sodium,
potassium, rubidium, caesium, and francium. Preferred are potassium
and caesium, and particularly preferred is caesium.
[0025] Examples of the alkaline earth metal are magnesium, calcium,
strontium, barium, and radium. Preferred are magnesium, barium, and
calcium, and particularly preferred is barium.
[0026] These elements may be used alone or in combination.
[0027] Upon preparation of the support for the catalyst, these
elements may be used in the form of oxide, hydroxide, carbonate,
nitrate, chloride, sulfate, or acetate.
[0028] When these elements are used as the support for the
catalyst, they are generally used in the crystallinity form of
oxide or carbonate.
[0029] The catalyst support used in the present invention contains
a cerium oxide or rare earth element oxide which is composed
principally of a cerium oxide in an amount of 5 to 40 percent by
mass, and preferably 10 to 35 percent by mass. The rare earth metal
oxide in an amount of less than 5 percent by mass is insufficient
in the effects of suppressing carbon to precipitate, facilitating
the activity, and enhancing the heat-resistance under coexistence
of oxygen, while that in amount of more than 40 percent by mass
reduces the catalyst surface, leading to insufficient catalyst
activity.
[0030] The catalyst support used in the present invention contains
the aluminum oxide in an amount of 60 to 95 percent by mass, and
preferably 65 to 90 percent by mass. The aluminum oxide of less
than 60 percent by mass reduces the catalyst surface, leading to
insufficient catalyst activity, while that in excess of 95 percent
by mass is insufficient in the effects of suppressing carbon to
precipitate, facilitating the activity, and enhancing the
heat-resistance under coexistence of oxygen.
[0031] The catalyst support used in the present invention contains
the alkaline metal and/or alkaline earth metal in an amount of 0 to
10 percent by mass in terms of metal. The upper limit is 10 percent
by mass, but is preferably 7 percent by mass or less. The alkaline
metal and/or alkaline earth metal in excess of 10 percent by mass
would invite the possibility that the catalyst activity is reduced.
No particular limitation is imposed on the lower limit. Therefore,
this component may not be present at all, but may be present in an
amount of generally 0.5 percent by mass or more, and preferably 0.8
percent by mass or more.
[0032] It is preferred that the cerium oxide or rare earth metal
element oxide which is composed principally of a cerium oxide, the
aluminum oxide and the alkaline metal and/or alkaline earth metal
be well-dispersed in the support.
[0033] No particular limitation is imposed on the method of
producing the support used in the present invention, which may,
therefore, be produced by any known suitable method at ease. For
example, the support may be produced by impregnating an aluminum
oxide with an water-soluble solution of a salt of cerium or a rare
earth metal which is composed-principally of cerium, followed by
drying and calcination. Eliqible salts for this method are
water-soluble salts. Preferred salts are nitrates, chlorides,
sulfates, and acetates. Particularly preferred are nitrates or
organic acid salts which are easily decomposed by calcination and
become oxides.
[0034] The calcination is generally effected in the air or an
oxygen atmosphere. No particular limitation is imposed on the
temperature as long as it is the decomposition temperature of the
salt or higher. However, the temperature is generally 500 to
1,400.degree. C., and preferably 700 to 1,200.degree. C.
[0035] Alternatively, the support may be prepared by
coprecipitation, gel-kneading, and sol-gel methods.
[0036] In the case of preparing a support containing an alkaline
metal and/or alkaline earth metal, no particular limitation is
imposed on the method of adding the alkaline metal and/or alkaline
earth metal into the support. For example, when a cerium oxide or
rare earth element oxide which is composed principally of a cerium
oxide is prepared, an aluminum oxide is prepared, or a support
comprising a cerium oxide or rare earth element oxide which is
composed principally of a cerium oxide and an aluminum oxide is
prepared, a water-soluble solution of a nitrate, chloride or
acetate of an alkaline metal and/or alkaline earth metal is
impregnated into the precursor of the support, and then dried and
calcined. Alternatively, after preparing a support comprising a
cerium oxide or rare earth metal element oxide which is composed
principally of a cerium oxide, and an aluminum oxide, a
water-soluble solution of a nitrate, chloride or acetate of an
alkaline metal and/or alkaline earth metal is impregnated into the
support, and then dried and calcined.
[0037] Although the catalyst support can be obtained in such a
manner, it is preferred that the catalyst support be calcined in
the air or an oxygen atmosphere before ruthenium being supported on
the support. The calcination temperature is generally 500 to
1,400.degree. C., and preferably 700 to 1,200.degree. C.
[0038] In order to enhance the mechanical strength of the catalyst
support, a small amount of binder, such as silica and cement may be
added thereto.
[0039] No particular limitation is imposed on the shape of the
support used in the present invention. Therefore, any shape may be
suitably selected depending on the use of the catalyst. For
example, the support may take any type of shape such as pellet-,
granular-, honey-comb-, and sponge-like shape.
[0040] The catalyst of the present invention can be obtained by
supporting ruthenium on the above-described support. In the present
invention, rhodium is used as an active metal. Ruthenium is
supported in such an amount that the atomic ratio of cerium to
ruthenium (Ce/Ru) is 1 to 250, preferably 2 to 100, and more
preferably 3 to 50. The deviation of the atomic ratio from the
range is not preferred because there is a possibility that
sufficient catalyst activity may not be obtained.
[0041] The amount of ruthenium to be supported is 0.1 to 3.0
percent by mass, and preferably 0.5 to 2.0 percent by mass in terms
of metal based on the total mass of the catalyst (total mass of the
support and the active metal).
[0042] No particular limitation is imposed on the method of
supporting ruthenium on the support. Any known method may be
selected. For example, there may be employed impregnation,
deposition, co-precipitation, kneading, ion-exchange, and
pore-filling methods. Among these methods, particularly preferred
is impregnation.
[0043] The starting materials of ruthenium differ depending on the
method of supporting ruthenium and may be suitably selected.
However, generally, a chloride or nitrate of ruthenium may be used.
For example, in the case of employing impregnation, a solution
(generally water-soluble solution) of a salt of ruthenium is
prepared and impregnated into the support. The support is dried and
if necessary calcined.
[0044] The calcination is generally effected in the air or a
nitrogen atmosphere. No particular limitation is imposed on the
calcination temperature as long as it is the decomposition
temperature of the salt or higher. It is generally 200 to
800.degree. C., and preferably 300 to 600.degree. C.
[0045] It is preferred in the present invention to prepare the
catalyst by subjecting the support supporting ruthenium to a
reduction treatment under a reduction atmosphere, generally, a
hydrogen atmosphere at a temperature of 400 to 1,000.degree. C, and
preferably 500 to 700.degree. C.
[0046] In the present invention, the catalyst may further contain
other noble metals such as rhodium, platinum, iridium, and
palladium supported on the support as well to an extent not to
hinder the achievement of purpose of the invention.
[0047] The surface area of the catalyst of the present invention is
generally 5 to 200 m.sup.2/g, and preferably 10 to 150 m.sup.2/g,
while the pore volume is generally 0.05 to 1.0 cm.sup.3/g, and
preferably 0.1 to 0.7 cm.sup.3/g.
[0048] No particular limitation is imposed on the shape of the
catalyst. Therefore, it may be selected suitably depending on the
use of the catalyst. For example, the catalyst may take any
suitable shape such as pellet-, granular-, honey-comb-, and
sponge-like shape.
[0049] Next, a process of producing a fuel gas for a fuel cell is
described which process comprises a step of converting hydrocarbons
and/or oxygen-containing hydrocarbons to a reformed gas which is
composed principally of hydrogen by an autothermal reforming
reaction using the catalyst of the present invention.
[0050] In the case of using a gas as the feed stock in the
autothermal reforming reaction, the gas preheated to a
predetermined temperature is well-mixed with steam and air or
oxygen, and then introduced into a reactor filled with the
catalyst. In the case of using a liquid as the feed stock, the
liquid is evaporated, well-mixed with steam and air or oxygen, and
then introduced into a reactor filled with the catalyst. In the
case where sulfur is contained in the feed stock, it is preferred
that the feed stock be desulfurized before introducing into a
reactor.
[0051] The reaction temperature is generally 200 to 800.degree. C.,
and preferably 300 to 600.degree. C. at the inlet for the catalyst
bed, and generally 500 to 1,000.degree. C., and preferably 600 to
800.degree. C. at the exit for the catalyst bed.
[0052] The reaction pressure is generally atmospheric pressure to 5
MPa, and preferably atmospheric pressure to 1 MPa.
[0053] The steam to be introduced together with the feed stock is
introduced in such an amount that the steam/carbon ratio (molar
ratio) is 0.1 to 5.0, and preferably 0.5 to 3.0.
[0054] The oxygen to be introduced together with the feed stock is
introduced in such an amount that the O.sub.2/carbon ratio (molar
ratio) is 0.1 to 0.5, and preferably 0.2 to 0.4.
[0055] In the present invention, the feed stock for producing a
reformed gas which is composed principally of hydrogen may be
hydrocarbons, oxygen-containing hydrocarbons, and mixtures thereof.
Specific examples are petroleum products such as methane, ethane,
propane, butane, natural gas, LPG, manufactured gas, gasoline,
naphtha, kerosene, and liquid fuels having a boiling point within
the range of those thereof, alcohols such as methanol, ethanol, and
propanol, and ethers such as dimethyl ether. The lesser the sulfur
content, the better the hydrocarbons are. Particularly, it is
preferred that the sulfur content be 1 wtppm or less.
[0056] In the process of the present invention, the feed stock
hydrocarbons such as hydrocarbons and/or oxygen-containing
hydrocarbons are converted to a reformed gas which is composed
principally of hydrogen in the presence of the catalyst by an
autothermal reforming reaction. A fuel gas for a fuel cell is
generally supplied to a fuel cell stack by a process which is the
combination of the desulfurization of the feed stock hydrocarbons
prior to be subjected to an autothermal reforming treatment and the
carbon monoxide conversion or carbon monoxide selective oxidation
treatment of a reformed gas produced by an autothermal reforming.
Alternatively, in place of the carbon monoxide conversion or carbon
monoxide selective oxidation treatment after autothermal reforming,
a fuel gas may be supplied to a fuel cell stack by a process which
is the combination of the desulfurization with a hydro-refining
process using a hydrogen-permeable membrane.
[0057] The autothermal reforming catalyst of the present invention
has an extremely high activity and long working life. However, in
the case of continuing the use of the catalyst over a long period
of time, if necessary, the catalyst is preferably subjected to a
refresh treatment such as reduction under a reduction atmosphere,
generally, a hydrogen atmosphere at a temperature of 400 to
1,000.degree. C., and preferably 500 to 700.degree. C.
[0058] The autothermal reforming catalyst of the present invention
is not decreased in activity even using ruthenium which has
conventionally the tendency to be decreased in activity under an
oxygen atmosphere at elevated temperatures, leading to a sufficient
working life and can maintain the effect of suppressing carbon to
precipitate at a lower steam/carbon ratio. Furthermore, since the
catalyst comprises ruthenium which is cheaper among the noble
metals, it is advantageous in the industrial use.
EXAMPLES
[0059] The invention will be further described by way of the
following examples which are provided for illustrative purposes
only.
Example 1
[0060] (1) Preparation of Catalyst
[0061] .gamma.-alumina powder with a specific surface of 190
m.sup.2/g was dipped into a water-soluble solution of cerium
nitrate, and the water is evaporated therefrom. The powder was
dried at a temperature of 120.degree. C. for 3 hours and then
calcined in the air at a temperature of 800.degree. C. for 3 hours,
thereby preparing a catalyst support.
[0062] The support was dipped into a water-soluble solution of
ruthenium chloride, and then the water was evaporated therefrom.
The support was dried at a temperature of 120.degree. C. for 3
hours. After the support was pressed, it was ground and sifted,
thereby obtaining a granulated catalyst with a size of about 1 to 2
mm. The catalyst was reduced under a hydrogen circulation at a
temperature of 500.degree. C. for 3 hours thereby obtaining
Catalyst A. The chemical composition of Catalyst A is shown in
Table 1.
[0063] (2) Autothermal Reforming Reaction
[0064] A reaction tube with an inner diameter of 9 mm was filled
with 1 cc of Catalyst A and then set in a tube-like electric oven.
An autothermal reforming reaction was conducted by introducing
desulfurized kerosene with the properties shown in Table 2 as the
feed stock at an LHSV of 1.5 h.sup.-1 into the reaction tube at a
reaction temperature of 600.degree. C., a steam/carbon ratio (molar
ratio) of 3.0, and an oxygen/carbon ratio (molar ratio) of 0.33 and
at atmospheric pressure for 20 hours.
[0065] The reaction gas was analyzed using gas chromatogram to
determine the conversion rate by calculating the ratio of CO,
CO.sub.2, and CH.sub.4 converted from the feed stock, i.e.,
kerosene, based on carbon. The results after 20 hours are shown in
Table 1.
[0066] (3) Evaluation of Stability under an Oxygen Atmosphere
[0067] Catalyst A was calcined in the air at a temperature of
600.degree. C. for 5 hours thereby obtaining Catalyst A1. This
calcination in the air corresponds to the accelerated oxidative
deterioration conditions in an autothermal reforming reaction.
[0068] Thereafter, an autothermal reforming reaction was conducted
using desulfurized kerosene as the feed stock and Catalyst A1 under
the same conditions as those of the above (2) for 20 hours. The
conversion rate and the composition of the reformed gas after 20
hours are shown in Table 1.
Example 2
[0069] (1) Preparation of Catalyst
[0070] .gamma.-alumina powder with a specific surface of 190
m.sup.2/g was dipped into a water-soluble solution of cerium
nitrate, and the water is evaporated therefrom. The powder was
dried at a temperature of 120.degree. C. for 3 hours and then
calcined in the air at a temperature of 800.degree. C. for 3 hours,
thereby preparing a catalyst support. The support was dipped into a
water-soluble solution of barium nitrate, and the water was
evaporated therefrom. The support was dried at a temperature of
120.degree. C. for 3 hours and calcined in the air at a temperature
of 800.degree. C. for 3 hours.
[0071] The support was dipped into a water-soluble solution of
ruthenium chloride, and then the water was evaporated therefrom.
The support was dried at a temperature of 120.degree. C. for 3
hours. After the support was pressed, it was ground and sifted,
thereby obtaining a granulated catalyst with a size of about 1 to 2
mm. The catalyst was reduced under a hydrogen circulation at a
temperature of 500.degree. C. for 3 hours thereby obtaining
Catalyst B. The chemical composition of Catalyst B is shown in
Table 1.
[0072] (2) Autothermal Reforming Reaction
[0073] An autothermal reforming reaction was conducted for 20 hours
using desulfurizing kerosene as the feed stock and Catalyst B under
the same conditions as those of Example 1. The conversion rate and
the composition of the reformed gas after 20 hours are shown in
Table 1.
[0074] (3) Evaluation of Stability under an Oxygen Atmosphere
[0075] Catalyst B was calcined in the air at a temperature of
600.degree. C. for 5 hours thereby obtaining Catalyst B1. An
autothermal reforming reaction was conducted for 20 hours using
desulfurizing kerosene as the feed stock and Catalyst B1 under the
same conditions as those of Example 1. The conversion rate and the
composition of the reformed gas 20 hours are shown in Table 1.
Example 3
[0076] (1) Preparation of Catalyst
[0077] .gamma.-alumina powder with a specific surface of 190
m.sup.2/g was dipped into a water-soluble solution of cerium
nitrate, and the water is evaporated therefrom. The powder was
dried at a temperature of 120.degree. C. for 3 hours and then
calcined in the air at a temperature of 800.degree. C. for 3 hours,
thereby preparing a catalyst support. The support was dipped into a
water-soluble solution of magnesium nitrate, and the water was
evaporated therefrom. The support was dried at a temperature of
120.degree. C. for 3 hours and calcined in the air at a temperature
of 800.degree. C. for 3 hours.
[0078] The support was dipped into a water-soluble solution of
ruthenium chloride, and then the water was evaporated therefrom.
The support was dried at a temperature of 120.degree. C. for 3
hours. After the support was pressed, it was ground and sifted,
thereby obtaining a granulated catalyst with a size of about 1 to 2
mm. The catalyst was reduced under a hydrogen circulation at a
temperature of 500.degree. C. for 3 hours thereby obtaining
Catalyst C. The chemical composition of Catalyst C is shown in
Table 1.
[0079] (2) Autothermal Reforming Reaction
[0080] An autothermal reforming reaction was conducted for 20 hours
using desulfurizing kerosene as the feed stock and Catalyst C under
the same conditions as those of Example 1. The conversion rate and
the composition of the reformed gas after 20 hours are shown in
Table 1.
[0081] (3) Evaluation of Stability under an Oxygen Atmosphere
[0082] Catalyst C was calcined in the air at a temperature of
600.degree. C. for 5 hours thereby obtaining Catalyst C1. An
autothermal reforming reaction was conducted for 20 hours using
desulfurizing kerosene as the feed stock and Catalyst C1 under the
same conditions as those of Example 1. The conversion rate and the
composition of the reformed gas after 20 hours are shown in Table
1.
Example 4
[0083] (1) Preparation of Catalyst
[0084] .gamma.-alumina powder with a specific surface of 190
m.sup.2/g was dipped into a water-soluble solution of cerium
nitrate, and the water is evaporated therefrom. The powder was
dried at a temperature of 120.degree. C. for 3 hours and then
calcined in the air at a temperature of 800.degree. C. for 3 hours,
thereby preparing a catalyst support. The support was dipped into a
water-soluble solution of magnesium nitrate, and the water was
evaporated therefrom. The support was dried at a temperature of
120.degree. C. for 3 hours and calcined in the air at a temperature
of 800.degree. C. for 3 hours.
[0085] The support was dipped into a water-soluble solution of
ruthenium chloride, and then the water was evaporated therefrom.
The support was dried at a temperature of 120.degree. C. for 3
hours. After the support was pressed, it was ground and sifted,
thereby obtaining a granulated catalyst with a size of about 1 to 2
mm. The catalyst was reduced under a hydrogen circulation at a
temperature of 500.degree. C. for 3 hours thereby obtaining
Catalyst D. The chemical composition of Catalyst D is shown in
Table 1.
[0086] (2) Autothermal Reforming Reaction
[0087] An autothermal reforming reaction was conducted for 20 hours
using desulfurizing kerosene as the feed stock and Catalyst D under
the same conditions as those of Example 1. The conversion rate and
the composition of the reformed gas after 20 hours are shown in
Table 1.
[0088] (3) Evaluation of Stability under an Oxygen Atmosphere
[0089] Catalyst D was calcined in the air at a temperature of
600.degree. C. for 5 hours thereby obtaining Catalyst D1. An
autothermal reforming reaction was conducted for 20 hours using
desulfurizing kerosene as the feed stock and Catalyst D1 under the
same conditions as those of Example 1. The conversion rate and the
composition of the reformed gas after 20 hours are shown in Table
1.
Example 5
[0090] (1) Preparation of Catalyst
[0091] .gamma.-alumina powder with a specific surface of 190
m.sup.2/g was dipped into a water-soluble solution of cerium
nitrate, and the water is evaporated therefrom. The powder was
dried at a temperature of 120.degree. C. for 3 hours and then
calcined in the air at a temperature of 800.degree. C. for 3 hours,
thereby preparing a catalyst support. The support was dipped into a
water-soluble solution of potassium nitrate, and the water was
evaporated therefrom. The support was dried at a temperature of
120.degree. C. for 3 hours and calcined in the air at a temperature
of 800.degree. C. for 3 hours.
[0092] The support was dipped into a water-soluble solution of
ruthenium chloride, and then the water was evaporated therefrom.
The support was dried at a temperature of 120.degree. C. for 3
hours. After the support was pressed, it was ground and sifted,
thereby obtaining a granulated catalyst with a size of about 1 to 2
mm. The catalyst was reduced under a hydrogen circulation at a
temperature of 500.degree. C. for 3 hours thereby obtaining
Catalyst E. The chemical composition of Catalyst E is shown in
Table 1.
[0093] (2) Autothermal Reforming Reaction
[0094] An autothermal reforming reaction was conducted for 20 hours
using desulfurizing kerosene as the feed stock and Catalyst. E
under the same conditions as those of Example 1. The conversion
rate and the composition of the reformed gas after 20 hours are
shown in Table 1.
[0095] (3) Evaluation of Stability under an Oxygen Atmosphere
[0096] Catalyst E was calcined in the air at a temperature of
600.degree. C. for 5 hours thereby obtaining Catalyst E1. An
autothermal reforming reaction was conducted for 20 hours using
desulfurizing kerosene as the feed stock and Catalyst E1 under the
same conditions as those of Example 1. The conversion rate and the
composition of the reformed gas after 20 hours are shown in Table
1.
Example 6
[0097] (1) Preparation of Catalyst
[0098] .gamma.-alumina powder with a specific surface of 190
m.sup.2/g was dipped into a water-soluble solution of cerium
nitrate, and the water is evaporated therefrom. The powder was
dried at a temperature of 120.degree. C. for 3 hours and then
calcined in the air at a temperature of 800.degree. C. for 3 hours,
thereby preparing a catalyst support. The support was dipped into a
water-soluble solution of potassium nitrate, and the water was
evaporated therefrom. The support was dried at a temperature of
120.degree. C. for 3 hours and calcined in the air at a temperature
of 800.degree. C. for 3 hours.
[0099] The support was dipped into a water-soluble solution of
ruthenium chloride, and then the water was evaporated therefrom.
The support was dried at a temperature of 120.degree. C. for 3
hours. After the support was pressed, it was ground and sifted,
thereby obtaining a granulated catalyst with a size of about 1 to 2
mm. The catalyst was reduced under a hydrogen circulation at a
temperature of 500.degree. C. for 3 hours thereby obtaining
Catalyst F. The chemical composition of Catalyst F is shown in
Table 1.
[0100] (2) Autothermal Reforming Reaction
[0101] An autothermal reforming reaction was conducted for 20 hours
using desulfurizing kerosene as the feed stock and Catalyst F under
the same conditions as those of Example 1. The conversion rate and
the composition of the reformed gas after 20 hours are shown in
Table 1 .
[0102] (3) Evaluation of Stability under an Oxygen Atmosphere
[0103] Catalyst F was calcined in the air at a temperature of
600.degree. C. for 5 hours thereby obtaining Catalyst F1. An
autothermal reforming reaction was conducted for 20 hours using
desulfurizing kerosene as the feed stock and Catalyst F1 under the
same conditions as those of Example 1. The conversion rate and the
composition of the reformed gas after 20 hours are shown in Table
1.
Example 7
[0104] (1) Preparation of Catalyst
[0105] .gamma.-alumina powder with a specific surface of 190
m.sup.2/g was dipped into a water-soluble solution of cerium
nitrate, and the water is evaporated therefrom. The powder was
dried at a temperature of 120.degree. C. for 3 hours and then
calcined in the air at a temperature of 800.degree. C. for 3 hours,
thereby preparing a catalyst support. The support was dipped into a
water-soluble solution of caesium nitrate, and the water was
evaporated therefrom. The support was dried at a temperature of
120.degree. C. for 3 hours and calcined in the air at a temperature
of 800.degree. C. for 3 hours.
[0106] The support was dipped into a water-soluble solution of
ruthenium chloride, and then the water was evaporated therefrom.
The support was dried at a temperature of 120.degree. C. for 3
hours. After the support was pressed, it was ground and sifted,
thereby obtaining a granulated catalyst with a size of about 1 to 2
mm. The catalyst was reduced under a hydrogen circulation at a
temperature of 500.degree. C. for 3 hours thereby obtaining
Catalyst G. The chemical composition of Catalyst G is shown in
Table 1.
[0107] (2) Autothermal Reforming Reaction
[0108] An autothermal reforming reaction was conducted for 20 hours
using desulfurizing kerosene as the feed stock and Catalyst G under
the same conditions as those of Example 1. The conversion rate and
the composition of the reformed gas after 20 hours are shown in
Table 1.
[0109] (3) Evaluation of Stability under an Oxygen Atmosphere
[0110] Catalyst G was calcined in the air at a temperature of
600.degree. C. for 5 hours thereby obtaining Catalyst G1. An
autothermal reforming reaction was conducted for 20 hours using
desulfurizing kerosene as the feed stock and Catalyst G1 under the
same conditions as those of Example 1. The conversion rate and the
composition of the reformed gas after 20 hours are shown in Table
1.
Example 8
[0111] (1) Preparation of Catalyst
[0112] Silica-alumina powder with a specific surface of 180
m.sup.2/g was dipped into a water-soluble solution of cerium
nitrate, and the water is evaporated therefrom. The powder was
dried at a temperature of 120.degree. C. for 3 hours and then
calcined in the air at a temperature of 800.degree. C. for 3 hours,
thereby preparing a catalyst support. The support was dipped into a
water-soluble solution of caesium nitrate, and the water was
evaporated therefrom. The support was dried at a temperature of
120.degree. C. for 3 hours and calcined in the air at a temperature
of 800.degree. C. for 3 hours.
[0113] The support was dipped into a water-soluble solution of
ruthenium chloride, and then the water was evaporated therefrom.
The support was dried at a temperature of 120.degree. C. for 3
hours. After the support was pressed, it was ground and sifted,
thereby obtaining a granulated catalyst with a size of about 1 to 2
mm. The catalyst was reduced under a hydrogen circulation at a
temperature of 500.degree. C. for 3 hours thereby obtaining
Catalyst H. The chemical composition of Catalyst H is shown in
Table 1.
[0114] (2) Autothermal Reforming Reaction
[0115] An autothermal reforming reaction was conducted for 20 hours
using desulfurizing kerosene as the feed stock and Catalyst H under
the same conditions as those of Example 1. The conversion rate and
the composition of the reformed gas after 20 hours are shown in
Table 1.
[0116] (3) Evaluation of Stability under an Oxygen Atmosphere
[0117] Catalyst H was calcined in the air at a temperature of
600.degree. C. for 5 hours thereby obtaining Catalyst H1. An
autothermal reforming reaction was conducted for 20 hours using
desulfurizing kerosene as the feed stock and Catalyst H1 under the
same conditions as those of Example 1. The conversion rate and the
composition of the reformed gas after 20 hours are shown in Table
1.
Example 9
[0118] (1) Autothermal Reforming Reaction
[0119] An autothermal reforming reaction was conducted for 20 hours
using desulfurizing light naphtha with the properties shown in
Table 2 as the feed stock and Catalyst H in the same manner as that
of Example 1. The reaction was conducted at a temperature of
600.degree. C., a steam/carbon ratio (molar ratio) of 3.0, an
oxygen/carbon ratio (molar ratio) of 0.33, atmospheric pressure,
and an LHSV of 5 h.sup.-1. The properties of the feed stock are
shown in Table 1. The conversion rate and the composition of the
reformed gas after 20 hours are also shown in Table 1.
[0120] (2) Evaluation of Stability under an Oxygen Atmosphere
[0121] An autothermal reforming reaction was conducted for 20 hours
using desulfurizing light naphtha as the feed stock and Catalyst H1
under the same conditions as those of Example 1. The conversion
rate and the composition of the reformed gas after 20 hours are
also shown in Table 1.
Example 10
[0122] (1) Autothermal Reforming Reaction
[0123] An autothermal reforming reaction was conducted for 20 hours
using propane with a purity of 99.5% or higher and the properties
shown in Table 2 as the feed stock and Catalyst H in the same
manner as that of Example 1. The reaction was conducted at a
temperature of 600.degree. C., a steam/carbon ratio (molar ratio)
of 3.0, an oxygen/carbon ratio (molar ratio) of 0.33, atmospheric
pressure, and an LHSV of 10 h.sup.-1. The conversion rate and the
composition of the reformed gas after 20 hours are also shown in
Table 1.
[0124] (2) Evaluation of Stability under an Oxygen Atmosphere
[0125] An autothermal reforming reaction was conducted for 20 hours
using propane as the feed stock and Catalyst H1 under the same
conditions as those of Example 1. The conversion rate and the
composition of the reformed gas after 20 hours are also shown in
Table 1.
Comparative Example 1
[0126] (1) Preparation of Catalyst
[0127] .gamma.-alumina powder with a specific surface of190
m.sup.2/g was calcined in the air at a temperature of 800.degree.
C. for 3 hours thereby obtaining a support. The support was then
dipped into a water-soluble solution of ruthenium chloride, and the
water was evaporated therefrom. The support was dried at a
temperature of 120.degree. C. for 3 hours. After the support was
pressed, it was ground and sifted, thereby obtaining a granulated
catalyst with a size of about 1 to 2 mm. The catalyst was reduced
under a hydrogen circulation at a temperature of 500.degree. C. for
3 hours thereby obtaining Catalyst I. The chemical composition of
Catalyst I is shown in Table 1.
[0128] (2) Autothermal Reforming Reaction
[0129] An autothermal reforming reaction was conducted for 20 hours
using desulfurizing kerosene as the feed stock and Catalyst I under
the same conditions as those of Example 1. The conversion rate and
the composition of the reformed gas after 20 hours are shown in
Table 1.
[0130] (3) Evaluation of Stability under an Oxygen Atmosphere
[0131] Catalyst I was calcined in the air at a temperature of
600.degree. C. for 5 hours thereby obtaining Catalyst I1. An
autothermal reforming reaction was conducted for 20 hours using
desulfurizing kerosene as the feed stock and Catalyst I1 under the
same conditions as those of Example 1. The conversion rate and the
composition of the reformed gas after 20 hours are also shown in
Table 1.
Comparative Example 2
[0132] (1) Preparation of Catalyst
[0133] .gamma.-alumina powder with a specific surface of 190
m.sup.2/g was dipped into a water-soluble solution of cerium
nitrate, and the water is evaporated therefrom. The powder was
dried at a temperature of 120.degree. C. for 3 hours and then
calcined in the air at a temperature of 800.degree. C. for 3 hours,
thereby preparing a catalyst support. The support was dipped into a
water-soluble solution of caesium nitrate, and the water was
evaporated therefrom. The support was dried at a temperature of
120.degree. C. for 3 hours and calcined at a temperature of
800.degree. C. for 3 hours.
[0134] The support was dipped into a water-soluble solution of
ruthenium chloride, and the water was evaporated therefrom. The
support was dried at a temperature of 120.degree. C. for 3 hours.
After the support was pressed, it was ground and sifted, thereby
obtaining a granulated catalyst with a size of about 1 to 2 mm. The
catalyst was reduced under a hydrogen circulation at a temperature
of 500.degree. C. for 3 hours thereby obtaining Catalyst J. The
chemical composition of Catalyst J is shown in Table 1.
[0135] (2) Autothermal Reforming Reaction
[0136] An autothermal reforming reaction was conducted for 20 hours
using desulfurizing kerosene as the feed stock and Catalyst J under
the same conditions as those of Example 1. The conversion rate and
the composition of the reformed gas after 20 hours are shown in
Table 1.
[0137] (3) Evaluation of Stability under an Oxygen Atmosphere
[0138] Catalyst J was calcined in the air at a temperature of
600.degree. C. for 5 hours thereby obtaining Catalyst J1. An
autothermal reforming reaction was conducted for 20 hours using
desulfurizing kerosene as the feed stock and Catalyst J1 under the
same conditions as those of Example 1. The conversion rate and the
composition of the reformed gas after 20 hours are shown in Table
1.
[0139] As apparent from Table 1, Catalysts A to H are extremely low
in activity reduction even though they are calcined in the air
assuming oxidation deterioration at elevated temperature in an
autothermal reforming reaction, and is excellent in anti-oxidation
properties.
1 TABLE 1 Inventive Examples 1 2 3 4 5 6 Desulfurized Desulfurized
Desulfurized Desulfurized Desulfurized Desulfurized Feed Stock
Kerosene Kerosene Kerosene Kerosene Kerosene Kerosene Catalyst A A1
B B1 C C1 D D1 E E1 F F1 Catalyst Composition (mass %) SiO.sub.2
.multidot. Al.sub.2O.sub.3 -- -- -- -- -- -- -- -- -- -- -- --
Al.sub.2O3 balance balance balance balance balance balance balance
balance balance balance balance balance CeO.sub.2 20 20 20 20 20 20
10 10 10 10 10 10 Ba -- -- 5 5 -- -- -- -- -- -- -- -- Mg -- -- --
-- 5 5 5 5 -- -- -- -- K -- -- -- -- -- -- -- -- 5 5 -- -- Cs -- --
-- -- -- -- -- -- -- -- 5 5 Ru 1 1 1 1 1 1 2 2 2 2 2 2 Conversion
Rate 100 100 100 100 100 100 100 100 100 100 100 100 (%) Carbon
Precipitation <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
<0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Amount (mass %)
Composition of Reformed Gas (volume %, dry basis) H.sub.2 47.5 47.2
48.1 47.9 48.0 48.0 47.8 47.0 47.5 47.2 48.0 47.7 CO 7.0 6.8 7.1
7.0 6.9 7.0 7.5 7.0 7.1 6.7 7.0 6.9 CO.sub.2 15.1 15.3 15.0 15.2
15.1 15.5 15.0 15.1 15.3 15.4 15.2 15.3 CH.sub.4 0.2 0.2 0.2 0.2
0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 O.sub.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
0.2 0.2 0.2 0.2 0.2 N.sub.2 30.0 30.3 29.4 29.5 29.7 29.0 29.3 30.5
29.7 30.3 29.4 29.7 Inventive Examples Comparative Examples 7 8 9 1
2 Desulfurized Desulfurized Desulfurized 10 Desulfurized
Desulfurized Feed Stock Kerosene Kerosene Light Naptha Propane
Kerosene Kerosene Catalyst G G1 H H1 H H1 H H1 I I1 J J1 Catalyst
Composition (mass %) SiO.sub.2 .multidot. Al.sub.2O.sub.3 -- --
balance balance balance balance balance balance -- -- -- --
Al.sub.2O.sub.3 balance balance -- -- -- -- -- -- 99 99 balance
balance CeO.sub.2 10 10 10 10 10 10 10 10 -- -- 1 1 Ba -- -- -- --
-- -- -- -- -- -- -- -- Mg -- -- -- -- -- -- -- -- -- -- -- -- K --
-- -- -- -- -- -- -- -- -- -- -- Cs 5 5 5 5 5 5 5 5 -- -- 5 5 Ru 1
1 1 1 1 1 1 1 1 1 1 1 Conversion Rate 100 100 100 100 100 100 100
100 85 57 88 65 (%) Carbon Precipitation <0.1 <0.1 <0.1
<0.1 <0.1 <0.1 <0.1 <0.1 1 4 1 3 Amount (mass %)
Composition of Reformed Gas (volume %, dry basis) H.sub.2 47.3 47.0
47.5 46.9 46.0 45.9 45.9 45.8 46.0 24.8 46.2 35.0 CO 7.0 6.8 6.9
6.6 7.0 7.0 7.1 7.0 6.0 4.1 6.3 5.5 CO.sub.2 15.0 15.5 15.2 15.3
14.2 14.3 13.9 14.0 16.0 18.6 15.5 17.0 CH.sub.4 0.2 0.2 0.2 0.2
0.2 0.2 0.2 0.2 0.4 0.9 0.4 0.5 O.sub.2 0.2 0.2 0.2 0.2 0.1 0.1 0.1
0.1 0.3 0.4 0.2 0.3 N.sub.2 30.3 30.3 30.0 30.8 32.5 32.5 32.8 32.9
31.3 51.2 31.4 41.7
[0140]
2TABLE 2 Desulfurized Desulfurized Feed Stock Kerosene Light Naptha
Propane Density g/cm.sup.3 (@ 15.degree. C.) 0.7943 0.6407 0.5080
Distillation Properties Initial Point .degree. C. 154.0 25.5
Running Point at 10 vol. % .degree. C. 173.0 32.5 Running Point at
50 vol. % .degree. C. 199.0 41.5 Running Point at 90 vol. %
.degree. C. 239.0 60.0 Running Point at 95 vo1. % .degree. C. 248.5
66.0 End Point .degree. C. 262.5 71.5 Sulfur Contents mass ppm
<1 <1 <1 Composition Paraffins volume ppm 84.6 99.9
Ofefins volume ppm 0.0 0.0 Aromatics volume ppm 15.4 0.1
* * * * *