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Sommaire du brevet 2635312 

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Disponibilité de l'Abrégé et des Revendications

L'apparition de différences dans le texte et l'image des Revendications et de l'Abrégé dépend du moment auquel le document est publié. Les textes des Revendications et de l'Abrégé sont affichés :

  • lorsque la demande peut être examinée par le public;
  • lorsque le brevet est émis (délivrance).
(12) Brevet: (11) CA 2635312
(54) Titre français: CATALYSEUR DE PRODUCTION DE GAZ SYNTHETIQUE
(54) Titre anglais: CATALYST FOR PRODUCTION OF SYNTHESIS GAS
Statut: Octroyé
Données bibliographiques
(51) Classification internationale des brevets (CIB):
  • B01J 23/887 (2006.01)
  • B01J 37/03 (2006.01)
  • B01J 37/04 (2006.01)
  • B01J 37/06 (2006.01)
  • C01B 3/40 (2006.01)
(72) Inventeurs :
  • WANG, HUI (Canada)
  • ZHANG, JIANGUO (Canada)
  • DALAI, AJAY KUMAR (Canada)
(73) Titulaires :
  • UNIVERSITY OF SASKATCHEWAN (Canada)
(71) Demandeurs :
  • UNIVERSITY OF SASKATCHEWAN (Canada)
(74) Agent: OYEN WIGGS GREEN & MUTALA LLP
(74) Co-agent:
(45) Délivré: 2013-01-08
(22) Date de dépôt: 2008-06-19
(41) Mise à la disponibilité du public: 2009-12-19
Requête d'examen: 2012-03-09
Licence disponible: S.O.
(25) Langue des documents déposés: Anglais

Traité de coopération en matière de brevets (PCT): Non

(30) Données de priorité de la demande: S.O.

Abrégés

Abrégé français

La présente invention concerne un nouveau catalyseur à oxyde métallique composite, un procédé de fabrication du catalyseur, et un processus de production de gaz de synthèse utilisant le catalyseur. Le catalyseur peut être un catalyseur à oxyde métallique composite à deux composants actifs, à base de nickel et de cobalt. Le catalyseur peut être utilisé pour produire du gaz de synthèse par la réaction de reformation de dioxyde de carbone du méthane. Le catalyseur sur une base anhydre après calcinations répond à la formule empirique suivante : (voir formule ci-dessus). M m+ et N n+ sont deux métaux de transition qui sont les deux composants actifs et sont choisis dans le groupe constitué par Ni, Co, Fe, Mn, Mo, Cu, Zn ou leurs mélanges, a+b+c+d=1, et 0,001<=a<=0,8, 0,001<=b<=0,8, 0,1<=c<=0,99, 0,01<=d<=0,99.


Abrégé anglais





The present invention relates to a novel composite metal oxide catalyst, a
method of
making the catalyst, and a process for producing synthesis gas using the
catalyst. The
catalyst may be a nickel and cobalt based dual-active component composite
metal
oxide catalyst. The catalyst may be used to produce synthesis gas by the
carbon
dioxide reforming reaction of methane. The catalyst on an anhydrous basis
after
calcinations has the empirical formula:

(see above formula)
M m+ and N n+ are two transition metals serving as dual-active components and
selected
from the group consisting of Ni, Co, Fe, Mn, Mo, Cu, Zn or mixtures thereof,
a+b+c+d=1, and 0.001<=a<=0.8, 0.001 <=b<=0.8,
0.1<=c<=0.99, 0.01<=d<=0.99.

Revendications

Note : Les revendications sont présentées dans la langue officielle dans laquelle elles ont été soumises.





-29-
CLAIMS


1. A nickel-cobalt bimetallic catalyst for production of synthesis gas by CO2
reformation
of hydrocarbon, the catalyst comprising a reduction product of a composite
metal oxide
having a chemical composition on an anhydrous basis after calcination
expressed by the
empirical formula:

Image
wherein
m and n are the valences of Ni and Co respectively and equivalent to 2 or 3,
a, b, c
and d are mole fractions wherein a+ b+ c+ d= 1, and 0.001 <= a <=
0.8, 0.001 <= b <= 0.8, 0.1 <=
c <=0.99, and 0.01 <=d <=0.99;

wherein the reduction product comprises active components comprising the metal

form of Ni, Co, and/or their alloy.

2. A catalyst according to claim 1 wherein the catalyst has a Ni and Co
combined
particle size < 10 nm.

3. A catalyst according to claim 2 wherein the catalyst has a Ni and Co
combined
dispersion of at least 5%.

4. A catalyst according to claim 3 wherein the catalyst has a Brunauer Emmett
Teller
(BET) specific area of at least 50 m2/g.

5. A catalyst according to claim 4 wherein the catalyst has a porous volume of
at least
0.050 cm3/g.

6. A catalyst according to claim 5 wherein the catalyst has an average pore
diameter no
greater than 100 .ANG..

7. A process for preparing a catalyst according to claim 1 comprising the
steps of:
(a) dissolving water soluble metal salts comprising inorganic or organic metal
salts of
Ni, Co, Mg, and Al;




-30-

(b) adding a basic solution of a precipitation reagent into an acidic solution
of the
metal salts of step (a) to generate a precipitate;
(c) washing the precipitate;
(d) drying the precipitate;
(e) calcining the precipitate; and
(f) activating the catalyst before reaction in a flow stream comprising H2.

8. A process according to claim 7 wherein the metal salts comprise nickel
nitrate, cobalt
nitrate, magnesium nitrate and aluminium nitrate.

9. A process according to claim 8 wherein step (e) comprises calcining the
precipitate in
air for 2 to 20 hours at 300 to 1300° C.

10. A process according to claim 9 wherein step (f) comprises activating the
catalyst for
0.5 to 50 hours at 200 to 1000° C.

11. A process according to claim 10 wherein the precipitation reagent
comprises
ammonia.

12. A process for producing synthesis gas using a catalyst according to claim
1 for
reforming a hydrocarbon or biogas with an oxidant.

13. A process according to claim 12 wherein the hydrocarbon is selected from
the group
consisting of methane, natural gas, petroleum gas, naphtha, heavy oil, crude
oil and their
mixtures.

14. A process according to claim 13 wherein the oxidant is selected from the
group
consisting of steam, carbon oxide, carbon dioxide, oxygen and their mixtures.

15. A process according to claim 14 where the oxidant is carbon dioxide and
the
hydrocarbon is methane or natural gas.

16. A process according to claim 12 wherein the molar ratio between the
oxidant and the
hydrocarbon is in the range of 0.5 to 10.




-31-


17. A process according to claim 16 wherein gas hourly space velocity is 2,000
to
2,000,000 mL/g cat.cndot.h.

18. A process according to claim 17 wherein reaction temperature is 300 to
1300° C.
19. A process according to claim 18 wherein reaction pressure is 0.1 to 20
atm.

20. A process according to claim 19 wherein the process is conducted in a
fixed bed
reactor or a fluidized bed reactor.

21. A process according to claim 12 wherein the hydrocarbon is methane, the
oxidant is
carbon dioxide, reaction temperature is 400 to 900° C., reaction
pressure is about 1 atm, feed
gas is CH4/CO2 at a 1:1 molar ratio and gas hourly space velocity is 2,000 to
2,000,000
mL/gcat.cndot.h.

22. A catalyst according to claim 1 wherein 0.001 <= a<= 0.068 and
0.01 <= b<=0.10.

23. A catalyst according to claim 1 wherein the composite metal oxide
comprises spinel
phases of combinations of Ni, Co, Al, Mg, and O.

24. A composite metal oxide of the catalyst according to claim 22.

Description

Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.



CA 02635312 2008-06-19

CATALYST FOR PRODUCTION OF SYNTHESIS GAS
FIELD OF THE INVENTION

loooll The present invention relates generally to catalysts for producing
synthesis
gas, and more particularly to catalysts for producing synthesis gas by carbon
dioxide
reforming of hydrocarbons.

BACKGROUND OF THE INVENTION

100021 Synthesis gas is a mixture of gases including varying amounts of carbon
monoxide and hydrogen. Synthesis gas may be used, for example, as an
intermediate in
the production of synthetic natural gas, synthetic petroleum, ammonia and
methanol.
Synthesis gas may be produced by carbon dioxide reforming reactions of

hydrocarbons. particularly light hydrocarbons such as methane.

100031 Synthesis gas may be produced by carbon dioxide reforming of methane
according to the following reaction:

CH4 + CO, = 2CO + 2H, 247kJ = mol-'

100041 This reaction is highly endothermic and generally requires temperatures
in the
range of 600 to 1100 to drive the reaction forward. Reforming catalysts such
as
Ni/A12O3, Ni/MgO/Al2O3 and the like may be used to catalyze the reaction.
Reforming

catalysts used in the above reaction are generally Group VIII metals held on
various
supports.

100051 Problems with known reforming catalysts include severe and rapid
deactivation as a result of coking, or carbon deposition on the catalyst.
Often, known


CA 02635312 2008-06-19
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catalysts are expensive to produce (e.g. some noble metal catalysts) and/or
have low
selectivity for target products such as hydrogen and carbon monoxide. Carbon
dioxide
reforming of methane to produce synthesis gas has therefore yet to be
established on a
commercial scale.


100061 It is desirable to provide a stable, inexpensive reforming catalyst
with high
catalytic activity and high selectivity for products such as hydrogen and
carbon
monoxide.

SUMMARY OF THE INVENTION

100071 One aspect of the present invention provides a catalyst composition
having a
dual-active component composite metal oxide for production of synthesis gas.
The
dual-active component composite metal oxide has a chemical composition on an

anhydrous basis after calcination expressed by the empirical formula:
Ma +Nb+A1~+Mg2+o am hn
(-++-C+a)
7 7 7

wherein Mm+ and Nn+ are two transition metals serving as dual-active
components and
selected from the group consisting of Ni, Co, Fe. Mn, Mo, Cu, Zn or mixtures
thereof,
m and n are the valences of M and N respectively and equivalent to 2 or 3, a,
b, c and
d are mole fractions with the proviso that a + b + c + d = 1 and 0.001 < a <
0.8, 0.001
<b <0.8, 0.1 <c <0.99, 0.01 <d <0.99.

100081 Another aspect of the present invention provides a process for
preparing a
catalyst composition having a dual-active component composite metal oxide for
production of synthesis gas. The dual-active component composite metal oxide
has a
chemical composition on an anhydrous basis after calcination expressed by the
empirical formula:


CA 02635312 2008-06-19
-3-
Ma +Nb+A13+Mga+O am bn 3
( + +-c+d)
2

wherein Mm+ and Nõ+ are two transition metals serving as dual-active
components and
selected from the group consisting of Ni, Co, Fe, Mn, Mo, Cu, Zn or mixtures
thereof,
m and n are the valences of M and N respectively and equivalent to 2 or 3, a,
b, c and
d are mole fractions with the proviso that a + b + c + d = I and 0.001 < a <
0.8, 0.001
< b < 0.8, 0.1 < c < 0.99, 0.01 < d < 0.99. The process includes the steps of.

(a) dissolving water soluble metal salts comprising inorganic or organic salts
of Mg,
Al and two transition metals selected from the group consisting of Ni, Co, Fe,
Mn, Mo, Cu, Zn and mixtures thereof;

(b) adding a basic solution of a precipitation reagent into an acidic solution
of the
metal salts of step to generate a precipitate;

(c) washing the precipitate;
(d) drying the precipitate:

(e) calcining the precipitate; and

(f) activating the catalyst composition before reaction in a flow stream
comprising
H2-

100091 A further aspect of the present invention provides a process for
producing
synthesis gas using a catalyst composition for reforming a hydrocarbon or
biogas with
an oxidant. The catalyst composition has a dual-active component composite
metal
oxide for production of synthesis gas. The dual-active component composite
metal
oxide has a chemical composition on an anhydrous basis after calcination
expressed by
the empirical formula:

Ma +Nn+A1~+Mga+O nn 3
2 2 7

wherein Mm+ and N + are two transition metals serving as dual-active
components and


CA 02635312 2008-06-19
-4-

selected from the group consisting of Ni, Co, Fe, Mn, Mo, Cu, Zn or mixtures
thereof,
m and n are the valences of M and N respectively and equivalent to 2 or 3, a,
b, c and
d are mole fractions with the proviso that a + b + c + d = I and 0.001 < a <
0.8, 0.001
<b <0.8, 0.1 <c <0.99, 0.01 <d <0.99.


BRIEF DESCRIPTION OF THE DRAWINGS

100101 Further features and advantages of the invention will be shown by the
following detailed description of the preferred embodiments of the present
invention
combined with the drawings in which:

Fig. I is a graph showing CH4 conversion as a function of time-on-stream (TOS)
for a
28-h activity and stability test of certain embodiments of the present
invention.

Fig. 2 is a graph showing relative H2 and CO production as a function of TOS
for a
28-h activity and stability test of certain embodiments of the present
invention;
Fig. 3 is a graph showing average carbon deposition rate for a 28-h activity
and
stability test of certain embodiments of the present invention;


Fig. 4 is a graph showing carbon deposition and CH4 conversion as a function
of TOS
for 20.200 and 2000-h activity and stability tests of a certain embodiment of
the
present invention;

Fig. 5 is a graph showing H2/CO formation as a function of TOS for 20, 200 and
2000-h activity and stability tests of certain embodiments of the present
invention;
Fig. 6 is a graph showing CH4 conversion as a function of TOS for a 250-h
activity
and stability tests of certain embodiments of the present invention;



CA 02635312 2008-06-19
-5-

Figs. 7(a) and (b) are graphs. for a 250-h activity and stability tests of
certain
embodiments of the present invention, (a) showing thermo-gravimetric (TG)
profiles
of spent catalysts; and (b) showing differential thermo-gravimetric (DTG)
profiles of
spent catalysts


Figs. 8(a) to (d) are transmission electron microscopy (TEM) micrographs of
catalysts
before and after a 250-h testing period for a 250-h activity and stability
test of certain
embodiments of the present invention. namely (a) Catalyst 5 before reaction;
(b)
Catalyst I before reaction; (c) Catalyst 5 after reaction; and (d) Catalyst I
after

reaction;

Fig. 9 is a graph showing temperature-programmed reduction (TPR) profiles of
certain embodiments of the present invention;

Fig. 10 is a graph showing X-ray powder diffraction (XRD) profiles of certain
embodiments of the present invention;

Figs. 11(a) and (b) are X-ray photoelectron spectroscopy (XPS) Ni 2P3/2 and Co
2P3/2
spectra of certain embodiments of the present invention;


Fig. 12 is a graph showing CH4 conversion as a function of TOS in solid lines
and
CO2 conversion as a function of TOS in dotted lines for a 28-h activity and
stability
tests of certain embodiments of the present invention;

Fig. 13 is a graph showing CH4 conversion and CO2 conversion as functions of
gas
hourly space velocity (GHSV) for activity and stability tests of a certain
embodiment
of the present invention;

Fig. 14 is a graph showing CH4 conversion and CO2 conversion as functions of
reaction temperature for activity and stability tests of a certain embodiment
of the


CA 02635312 2008-06-19
-6-
present invention;

Fig. 15 is a graph showing CH4 conversion as a function of TOS for a2000-h
activity
and stability test of a certain embodiment of the present invention;


Fig. 16 is a graph showing CO2 conversion as a function of TOS for a 2000-h
activity
and stability test of a certain embodiment of the present invention;

Fig. 17 is a graphshowing CO selectivity as a function of TOS for a 2000-h
activity
and stability test of a certain embodiment of the present invention;

Fig. 18 is a graph showing H2 selectivity as a function of TOS for a 2000-h
activity
and stability test of a certain embodiment of the present invention;

Fig. 19 is a graph showing variation of the BET surface area with
(Ni+Co)/(A1+Mg)
ratio for certain embodiments of the present invention;

Fig. 20 is a graph showing XRD profiles of certain embodiments of the present
invention (o denoting spinel-like structures and ^ denoting solid solutions);


Fig. 21 is a graph showing TPR profiles of certain embodiments of the present
invention;

Fig. 22 is a graph showing pore size distribution of certain embodiments of
the
present invention;

Figs. 23(a) to (d) are pre-reaction TEM micrographs and particle size
distribution
graphs of certain embodiments of the present invention as defined in Example 7
of the
following description, namely (a) Catalyst 18; (b) Catalyst 17; (c) Catalyst
16; and (d)
Catalyst 15;


CA 02635312 2008-06-19
-7-

Fig. 24 is a graph showing C1-I4 conversion as a function of TOS for a 250-h
activity,
and stability test of certain embodiments of the present invention.

Figs. 25(a) and (b) are graphs, for a 250-h activity and stability tests of
certain
embodiments of the present invention, showing: (a) TG profiles of spent
catalysts;
and (b) DTG profiles of spent catalysts; and

Figs. 26(a) to (d) are post-reaction TEM micrographs of certain embodiments of
the
present invention, namely (a) Catalyst 18; (b) Catalyst 17; (c) Catalyst 16;
and (d)
Catalyst 15.

DETAILED DESCRIPTION OF THE INVENTION

100111 Throughout the following description specific details are set forth in
order to
provide a more thorough understanding to persons skilled in the art. However,
well
known elements may not have been shown or described in detail to avoid
unnecessarily
obscuring the disclosure. Accordingly. the description and drawings are to be
regarded
in an illustrative, rather than a restrictive, sense.


100121 In contrast to problems associated with known reforming catalysts, the
present
invention provides a catalyst having high activity, high stability, and high
yield of
synthesis gas. The term synthesis gas, as used in this specification, includes
carbon
monoxide, hydrogen and gas mixtures containing carbon monoxide and hydrogen.


(00131 In particular, the present invention relates to a dual-active component
composite metal oxide catalyst for reforming reactions of hydrocarbons, a
method of
preparing the catalyst. and a process for producing synthesis gas using the
catalyst.
Preparation and use of the catalyst is inexpensive and simple. The terms dual-
active


CA 02635312 2008-06-19
-8-

component composite metal oxide catalyst and bimetallic catalyst are used
interchangeably in this specification.

100141 The catalyst according to one embodiment of the present invention has a
chemical composition on an anhydrous basis after calcination expressed by the
empirical formula:

Ma+Nn+Al3+Mg2+O az bn s
2 2 2

where M and N are two transition metals selected from Ni, Co, Fe, Mn, Mo, Cu,
Zn or
mixtures thereof.

100151 The letters '*m and "n" represent the valence of M and N, respectively,
and
are equivalent to 2 or 3 depending on the transition metals selected. The
letters "a" "b",
"c" and "d" represent mole fractions of M. N. Al and Mg. respectively, with
the
provisos that a + b + c + d = 1.

100161 The mole fraction of M is 0.001 < a < 0.8, preferably 0.005 < a < 0.5,
and even
more preferably 0.01 < a < 0.1. The mole fraction of N is 0.001 < b < 0.8,
preferably
0.005 < b < 0.5, and even more preferably 0.01 < b < 0.1.

100171 M combines with N resulting in two active components in the catalyst
composition. The interaction between M and N has been discovered to improve
the
selectivity of the catalyst and suppresses coking. These interactions may
include strong

metal-support interaction (SMSI) and formation of stable solid solutions. M
and N,
particularly at lower molar fractions, also have a smaller metal particle size
and higher
dispersion to improve catalytic performance and reduce coking or carbon
deposition. M
may be Ni and N may be Co in certain embodiments.


CA 02635312 2008-06-19
-9-

100181 The overall mole fraction of M and N is 0.001 < (a + b) < 0.8,
preferably 0.005
< (a + b) < 0.5. and even more preferably 0.01 < (a + b) < 0.5. When the
overall mole
fraction of M and N is less than 0.005, the activity of the catalyst
decreases, and when
the overall mole fraction of M and N exceeds 0.8, the stability of the
catalyst decreases
due to coking and sintering.

100191 The mole fraction of Al is 0.01 < c < 0.99, preferably 0.05 < c < 0.95,
and even
more preferably 0.05 < c < 0.9. Aluminium increases the specific area and
improves the
pore structure and distribution of the catalyst.


100201 The mole fraction of Mg is 0.01 < d < 0.99, preferably 0.05 < d < 0.95,
and
even more preferably 0.1 < d < 0.95. The high melting point of MgO which forms
during the process of calcination significantly increases the resistance of
catalyst to
sintering greatly. The basicity of MgO may also play a role in depressing
coking.


100211 The overall mole fraction of Mg and Al is 0.1 < (c + d) < 0.99,
preferably 0.15
< (c + d) < 0.90. and even more preferably 0.2 < (c + d) < 0.90. The
combination of Al
and Mg results in the formation of spinel MgAh04 and periclase MgO after
calcination
in air, and serves as a support for the dual-active components M and N of the
catalyst.

When the overall mole fraction of magnesium and aluminium is less than 0.1,
the
catalyst is unstable due to severe coking and sintering. Activity of the
catalyst is also
poor when the overall mole fraction of magnesium and aluminium exceeds 0.99.
The
combination of magnesium and aluminium has two important effects on the
stability
and activity of the catalyst: increasing resistance to sintering at high
temperature and

keeping a relatively high and stable specific area and pore structure of the
catalyst to
increase the contact area of reaction.

100221 Any suitable method may be used to prepare the catalyst of the present
invention. including co-precipitation, impregnation. homogenous precipitation,
and
so]-gel. Co-precipitation and impregnation are preferred methods.


CA 02635312 2008-06-19
-10-

100231 When using a co-precipitating method, one or more water soluble salts
selected from nickel, cobalt. manganese, iron, molybdenum, copper, and zinc,
one
water soluble magnesium salt and one water soluble aluminium salt are together

dissolved in water. Water soluble salts can include inorganic salts, for
example,
nitrates, and organic salts, for example acetates.

100241 A precipitate is generated by adding a precipitation reagent to above
mixed
aqueous solution while stirring at 15 to 90 C. The precipitation reagent may
be selected
from NH4+, ON", and CO3` . Sodium carbonate, sodium bicarbonate, sodium
oxalate,

sodium hydroxide, potassium carbonate, potassium bicarbonate, potassium
oxalate,
potassium hydroxide, ammonium carbonate, ammonium bicarbonate, ammonia and the
like might be used as the precipitation reagent. Aqueous ammonia solution is a
preferred precipitation reagent.


100251 With the addition of a precipitation reagent. a precipitate is formed
comprising
the above metal components in the fonn of hydroxides. After precipitation, and
before
drying the precipitate, other unnecessary ions introduced with the
precipitation reagent,
such as Na'. K+, and Cl-. are removed from the precipitate by filtering and
washing with
distilled water.

100261 The precipitate is then dried at 70 to 150 C overnight. Next, the
dried
precipitate is calcined for 2 to 20 hours at 300 to 1300 C in air. It is
preferable to
calcinate for 4 to 12 hours at 600 to 1000 C. The catalyst is a composite
metal oxide at
this point.

100271 The catalyst may be crushed to 20 to 70 mesh for use. Prior to using
for
producing synthesis gas, the catalyst should be activated at 200 to 1000 C,
preferably
500 to 900 C. for 0.5 to 50 hours in a flow stream of 5 to 70% hydrogen. The
activation


CA 02635312 2008-06-19
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of the catalyst can be carried out in the reactor in which the reaction to
produce
synthesis gas will be performed.

100281 The catalyst may be used to produce synthesis gas by reacting a
hydrocarbon,
such as methane, natural gas. petroleum gas, naphtha, heavy oil, crude oil,
biogas, or
the like, and their mixtures with an oxidant, for example steam, carbon
dioxide or
oxygen. For example. the catalyst may be used for carbon dioxide reforming of
methane or natural gas.

100291 The molar ratio between oxidant and hydrocarbon is in the range of 0.5
to 10,
preferably 1.0 to 6.0, and even more preferably 1.0 to 3Ø It is not
necessary to use a
large molar ratio of oxidant to hydrocarbon when using the catalyst of the
present
invention. Inert gas such as nitrogen may be employed as reference gas for
calculation
of conversion and selectivity. The molar fraction of inert gas in feed gas is
in the range
of 10 to 80%.

100301 The gas hourly space velocity (GHSV, here defined as the volume flow
rate at
standard conditions divided by the mass of catalyst) is 2,000 to 2.000,000
mL/gnat h,
preferably 10,000 to 1,000.000 mL/gca,=h, and even more preferably 40,000 to
400, 000
mL/gcath.

100311 The reaction temperature is in the range of 300 to 1300 C, preferably
500 to
1100 C, and even more preferably 600 to 1000 T. The reaction pressure is in
the range
of 0. 1 to 20 atm, preferably 1 to 10 atm. and even more preferably I to 5
atm.


100321 The type of reactor that can be used can be any suitable reactor
including
conventional fixed bed reactors and fluidized bed reactors.

100331 The catalyst of the present invention is suitable primarily for dry
reforming of
light hydrocarbons and biogas, but may be used for other purposes such as wet


CA 02635312 2008-06-19
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reforming. For the purposes of synthesis gas production, dry reforming is
preferred
over wet reforming. The present invention may also be used in other contexts
such as
reduction of carbon dioxide emissions into the atmosphere.

100341 The present invention is demonstrated by the specific examples below,
but the
invention is not limited in scope thereto.

EXAMPLE 1: Catalyst preparation. characterization and testing

100351 The catalysts described in Examples 2-7 were prepared, characterized
and
tested according to the procedures described in this Example I below.

Catalyst preparation

100361 Bimetallic catalysts having an AI-Mg-O framework were prepared by
co-precipitating a common aqueous solution of nickel nitrate (98% purity,
Lancaster
Synthesis Inc.), cobalt nitrate (99% purity, Aldrich Chemical Company),
magnesium
nitrate (EMD Chemicals Inc.) and aluminium nitrate (EMD Chemicals Inc.). Other
bimetallic catalysts were prepared by replacing cobalt nitrate with iron (III)
nitrate

(99% purity, Lancaster Synthesis Inc.), manganese nitrate (99.98% purity,
Lancaster
Synthesis Inc.), or copper (II) nitrate (99% purity, Aldrich Chemical
Company). Yet
other bimetallic catalysts were prepared by replacing nickel nitrate with
manganese
nitrate. Monometallic catalysts were prepared by coprecipitating a common
aqueous
solution of either nickel nitrate or cobalt nitrate with magnesium nitrate and
aluminium
nitrate.

100371 The precipitations were conducted at room temperature at pH 8.5-9.5
adjusted
by titrating with aqueous ammonia solution. Precipitates were filtered and
washed with
de-ionized water, dried in air at 120 C overnight. calcined at 900 C in air
for 3 to10 h,
and crushed to 20-70 mesh size.


CA 02635312 2008-06-19
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Catalyst characterization

100381 Bulk metal compositions was measured by inductively coupled plasma mass
spectrometry (ICP-MS).

100391 Surface metal composition was measured by X-ray photoelectron
spectroscopy (XPS).

100401 Brunauer Emmett Teller (BET) surface area, pore measurements (volume,
diameter and size distribution) were measured using N2 adsorption at -1961
using a
Micromeritics Accelerated Surface Area and Porosimetry (ASAP) 2000 analyzer.
About 0.2 g of catalyst was used for each analysis. Before analysis. samples
were
evacuated at 2000C and 500 mHg (66.6 Pa) to remove moisture and other
adsorbed

gases from the catalyst surface. Sample were then evacuated at 20 mHg (2.67
Pa)
before N2 adsorption. Pore measurements were derived from the adsorpotion
branch of
the N2 isotherm by the Barret-Joyner-Halenda method.

100411 Metal dispersion and metal surface area were determined by

CO-chemisorption using a Micromeritics ASAP 2000 analyzer. Samples were first
reduced with H2 at 850 to 9000C for 4 h. Reduced samples were transferred to
the
sample holder of the analyzer under protection of an inert gas (He). Three
steps were
then carried out before CO-chemisorption: (1) evacuating the sample for 30
min. at 120
; (2) reducing the sample again at 4500C for 30 min. using H2; and (3)
evacuating the

sample again for another 30 min. at 120. CO-chemisorption was performed at
350x'.
100421 X-ray powder diffraction (XRD) analysis was conducted using a
Rigaku/Rotaflex Cu rotating anode X-ray diffraction instrument equipped with a
generator voltage of 40 kV and tube current of 40 mA. Samples were powdered
and

mixed with methanol to form a mud which was loaded on the coarse side of a
glass


CA 02635312 2008-06-19
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plate and placed under ambient drying conditions. Dried sample plates were
loaded into
the analysis chamber and scanned at a rate o f f /min., with 20 varying from
20 to 800.
10043] Reducibility was studied using temperature-programmed reduction (TPR)
in a

ChemBET-3000 chemisorpotion analyzer. Samples of about 0.1 g were heated from
room temperature to 1000`C using 3% H2/N2 at a flow rate of 30 mL/min. and a
ramp
rate of 50C/min.

100441 Carbon deposition was measured by a Perkin-Elmer Pyris Diamond

Thermo-Gravimetric and Differential Thermo-Gravimetric (TG/DTG) analyzer.

Spent catalyst samples were heated in a platinum sample holder from room
temperature
to 850 to1000t at a ramp rate of 5t/min.

100451 A JEOL-JEM-1200EX transmission electron microscope (TEM) operating at
100 kV was used to investigate morphology of carbon deposition on spent
catalysts and
metal particle size distribution of fresh catalysts.

Catalyst testing

10046] Catalyst were tested in a benchtop fixed-bed quartz microreactor with
an inner
diameter of 6 mm. Reactant feed gas consisting of an equimolar mixture of CH4
(99.2%, Praxair Canada Inc.), CO2 (99.9%. Praxair Canada Inc.) and N, (99.9%,
Praxair Canada Inc.) was introduced into the reactor at atmospheric pressure.
Before
testing, catalysts were activated (reduced) by an H2 (99.9%, Praxair Canada
Inc.) and

N2 mixture with a molar ratio of 1:4 to 1:9 at to 800 to 900t for 4 h.

100471 Gases produced by the carbon dioxide reforming of methane were analyzed
by
an online Agilent 6890 GC gas chromatography equipped with thermal
conductivity
detection (TCD) and a GS-GASPRO capillary column (J&W Scientific Inc.) of 60 m
in

length and 0.32 mm in inner diameter. Helium (ultra-high purity, Praxair
Canada Inc.)


CA 02635312 2008-06-19
-15-

was used as the carrier gas. The gas chromatography oven temperature was
initially
held at -600C for 3 min. and then increased to 30t at a ramp rate of 250C/min.
100481 The conversion rate of methane, selectivity of carbon monoxide, and

selectivity of hydrogen are calculated according to the following equations:
X, -H4
F,'.H - F' x
X
C(.H = x100%
Fx

F x X"O
SC , = X N X100%
X ,H X
i i CO-
F(Ha Fv X+ F0 FN x
X H,
n,
Sx X100%
2x F,.Ha X

where. CCH4 is the overall conversion of methane. S,o selectivity of carbon
monoxide.
SH2 selectivity of hydrogen, F'CH4 initial volume flow rate of methane. F'C02
initial
volume flow rate of carbon dioxide, F'N2 initial volume flow rate of nitrogen,
XCH4
molar fraction of methane in the product. XN2 molar fraction of nitrogen in
the
product, Xco molar fraction of carbon monoxide in the product, XH2 molar
fraction of
hydrogen in the product.

EXAMPLE 2: 28 h test of Catalysts 1-4

100491 Bimetallic catalysts containing Ni and one of Co, Mn, Fe and Cu were
prepared by coprecipitation and designated Catalysts 1-4 respectively. Bulk
metal
composition, BET surface area, pore volume and average pore diameter are shown
in
Table 1. Catalysts 2-4 (Ni-Mn. Ni-Fe and Ni-Cu) had similar levels of BET
surface area
at 14-18 m2/g, while Catalyst I (Ni-Co) had a significantly higher BET surface
area at


CA 02635312 2008-06-19
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53.5 m2/g. Pore volume followed the order Ni-Co >> Ni-Cu > Ni-Mn > Ni-Fe while
the
average pore diameter followed the order Ni-Co < Ni-Fe < Ni-Mn < Ni-Cu.

Table 1: Bulk metal composition, BET surface area, pore volume and average
pore
diameter of Catalysts 1-4

Bulk Metal Composition BET Average
Pore
(mol%) surface pore
No. Catalyst volume
area diameter
Ni Co Mn Fe Cu Al Mg (mL/g)
(m`'/g) (nm)
I Ni-Co 6.1 9.3 - - - 28.2 56.4 53.5 0.160 10.4
2 Ni-Mn 6.0 - 9.0 - - 27.8 57.1 17.2 0.073 16.9
3 Ni-Fe 6.5 - - 7.9 - 29.0 56.6 17.8 0.056 12.0
4 Ni-Cu 6.8 - - - 6.9 28.6 57.7 14.7 0.088 19.6
100501 To screen different bimetallic combinations, activity and stability of
Catalysts
1-4 over a 28-h period was investigated. Samples were prepared by diluting
0.05 g of

catalyst with 0.450 g quartz sand. Tests were run at 750, 1 atm, F = 5.5 L/h,
GHSV =
1 10,000 mL/gcat=h and CH4/CO2/N2 = l /1 /1. CH4 conversion rate as function
of
time-on-stream (TOS) is shown in Fig. 1. Catalyst I (Ni-Co) had a high initial
activity
(91.4% CH4 conversion rate) and remained at this level throughout the 28-h
testing
period. Catalyst 2 (Ni-Mn) and Catalyst 3 (Ni-Fe) also had high initial
activities, with

CH4 conversion rates of 85 and 53%. respectively; however, the conversion
dropped to
63 and 18%, respectively, at the end of the 28-h testing period. Catalyst 4
(Ni-Cu)
showed low but relatively stable activity. with a CH4 conversion rate of <
16%. Thus,
initial activity followed the order Ni-Co > Ni-Mn > Ni-Fe > Ni-Cu, which is
consistent
with the order of BET surface area, pore volume and average pore diameter
(Table 1).

The ratio of H2 to CO selectivity. shown in Fig. 2, reflects no obvious
difference in the
relative amounts of H2 and CO produced when using the different bimetallic
catalysts.


CA 02635312 2008-06-19
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100511 After the 28-h testing period, the amount of carbon deposited on the
spent
catalysts was analyzed. Average rates of carbon deposition are shown in Fig.
3.
Catalyst 3 (Ni-Fe) had a high carbon deposition rate of 0.02104 gc/gcat-h and

corresponding high activity decay of 67% (calculated on the basis of initial
and final
CH4 conversion rates). Catalyst 2 (Ni-Mn) also had a relatively high carbon
deposition
rate of 0.00543 gc/gnat-h and corresponding activity decay of 26%. Catalyst 4
(Ni-Cu)
had a lower carbon deposition rate of 0.00222 gc/gcat-h and an activity decay
of 22%.
Catalyst I (Ni-Co) had the lowest deposition rate, at 0.00204 gc/gcat-h and no
activity

decay over the 28-h testing period. Activity decay followed the same order as
carbon
deposition rate: Ni-Fe >> Ni-Mn > Ni-Cu > Ni-Co.

EXAMPLE 3: 20, 200 and 2000 h tests of Catalyst 1

100521 To investigate stability and carbon deposition over a longer term.
Catalyst 1
(Ni-Co) was tested for 20, 200 and 2000 h. respectively. Again, samples were
prepared
by diluting 0.05 g of catalyst with 0.450 g quartz sand. Tests were run at
7501, 1 atm,
F= 5.5 L/h, and CH4/CO2/N2 = 1/1/1. CH4 conversion rates and carbon deposition
are
shown in Fig. 4.


100531 In the 20-h test, the CH4 conversion rate was maintained at about
0.000415
m01/goat-s, but the amount of carbon deposited was 0.0408 g,/g,a,. In the 200-
h test, the
CH4 conversion rate was maintained at about 0.000416 mol/gnat-s for 100 h but
dropped
to 0.000409 mol/goat-s at 200 h. Over the 200-h test. 0.2374 g,/gnat was
formed. In the

2000-h test, the CH4 conversion rate again began to drop at 100 h from the
initial
0.000415 to 0.000398 mol/goat-s at about 300 h, fluctuated between 0.000395
and
0.000407 mol/gnat-s until 700 h, and stayed stable at 0.000404 mol/goat-s for
the last
1300 h. The amount of carbon deposited was 0.435 g,/gnat over the 2000-h
period.


CA 02635312 2008-06-19
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100541 Carbon deposition on Catalyst I slowed with increasing TOS. The average
carbon deposition rate was 0.00204, 0.00119, and 0.000218 gc/gcat-h for the
20, 200 and
2000-h tests, respectively. Further calculations relating to the 2000-h test
showed the
average carbon deposition rate was 0.00204 gc/gnat-h for first 20 period of
TOS,

0.00109 gc/gcat-h for the following 180 h period and 0.000109 gc/gnat-h for
the last 1800
h. Overall, decline of catalytic activity for Catalyst I was remarkably low at
less than
3% over the 2000-h testing period.

100551 The molar ratio of H2/CO as a function of TOS is shown in Fig. 5.
Reverse
water-gas shift reaction (RWSR) is typically a significant reaction and
reduces the
H2/CO ratio in dry reforming of methane; however, the average H2/CO ratio over
the
2000-h testing period for Catalyst I was about 0.965, indicating the
occurrence of some
RWSR but of less significance than expected. The molar ratio of H2 to CO
oscillated
between 0.9 and 1.1 during the reaction period, suggesting a periodic cycle of
carbon

deposition and elimination on the catalyst surface leading to stable catalytic
performance.

EXAMPLE 4: 250 h test of Catalysts I and 5

100561 A Ni-Co bimetallic catalyst containing about half of the Ni and Co
loading of
Catalyst I was prepared by coprecipitation. This catalyst was designated
Catalyst 5.
The bulk metal composition of Catalyst 5 (and Catalyst I for comparison) is
shown in
Table 2.

Table 2: Bulk metal composition and surface metal composition of Catalysts I
and 5.
Bulk Metal Composition

No. Catalyst (mol%)

Ni Co Al Mg


CA 02635312 2008-06-19
-19-

1 Ni-Co 6.1 9.3 28.2 56.4
Ni-Co 3.6 4.9 30.0 61.5

100571 Activity and stability of Catalysts l and 5 over a 250-h period was
investigated. Samples were prepared by diluting 0.03 g of catalyst with 0.470
g of
quartz sand. Tests were run at 750 C, 1 atm. F= 5.5 L/h, and CH4/CO2/N2 =
1/1/1. CH4

5 conversion rate as function of TOS is shown in Fig. 6. The initial CH4
conversion rate
of Catalyst 5 was slightly lower than that of Catalyst 1. However, the CH4
conversion
rate of Catalyst 5 surpassed that of Catalyst 1 at an early point and remained
at a high
level to the end of the 250-h testing period.

100581 Thermo-gravimetric (TG) and differential thermo-gravimetric (DTG)
analysis
on the spent Catalysts l and 5 detected no carbon deposition on Catalyst 5 but
some
carbon deposition on Catalyst I (Fig. 7(a) and Fig. 7(b)). TEM analysis (Fig.
8(a))
further confirmed that no carbon formed on spent Catalyst 5. Fig. 7(b) shows
that there
were two kinds of carbon formed on Catalyst 1; one oxidizable in air at 500 C
and

another oxidizble in air at 600 T. Corresponding Fig. 8(d) shows filamentous
carbons
of nanotubes with two very different diameters formed on Catalyst 1. The
nanotubes of
different diameters may be responsible for the two DTG peaks.

100591 Fig. 8(a) and Fig. 8(b) show that particle size is smaller on Catalyst
5

compared to Catalyst 1. Metallic surface area and metal dispersion of
Catalysts I and 5
are shown in Table 3. For Catalyst 1, metallic surface area was 4.1 m2/g and
metal
dispersion was 7.5 %. Catalyst 5 had a lower metallic surface area of 2.9 m2/g
but
higher metal dispersion of 8.8 %. The higher metallic surface of Catalyst 1
likely
accounted for the higher initial activity (Fig. 6). However, its lower metal
dispersion

and thus larger ensembles may have resulted in relatively rapid carbon
deposition and
hence activity decay (Fig. 6 and Fig. 7). Carbon resistance of Catalyst 5 may
be due to
its higher metal dispersion and smaller metal ensembles.


CA 02635312 2008-06-19
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Table 3: BET surface area, average pore diameter, metallic surface area and
metal
dispersion of Catalysts 1, and 5-7

Average Metallic Metal
BET surface area
No. Catalyst pore diameter surface area dispersion
(m2/g)
(nm) (m2/g) (%)
I Ni-Co 54 10.4 4.1 7.5
Ni-Co 56 8.5 2.9 8.8
6 Ni 45 9.0 1.2 2.9
7 Co 24 10.5 1.5 2.1
5

EXAMPLE 5: 28 h test of Catalysts 5-7

100601 Comparative investigations were carried out on Ni and Co monometallic
catalysts and a Ni-Co bimetallic catalyst. specifically Catalyst 5. In the
monometallic
catalysts, Ni content or Co content was at roughly the same level as the
overall Ni and

Co content in Catalyst 5 so that the comparison of catalytic performance could
be made
on the basis of similar total active metal content. The Ni monometallic
catalyst was
designated Catalyst 6 and the Co monometallic catalyst was designated Catalyst
7.

100611 Bulk metal composition and surface metal composition of Catalysts 5-7
are
shown in Table 4. Comparison of surface composition and bulk composition
indicated
that Nisurface/N ibulk was 1.10 in monometallic Catalyst 6 and 1.19 in
bimetallic Catalyst
5. Cosurface/Cohuik was 0.80 and 1.27 in monometallic Catalyst 7 and
bimetallic Catalyst
5, respectively. Surface enrichment of Ni and Co (particularly Co) was
therefore

evident in bimetallic Catalyst 5.


CA 02635312 2008-06-19
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Table 4: Bulk metal composition and surface metal composition of Catalysts 5-7
Bulk Metal Composition Surface Metal Composition

No. Catalyst (mot%) (mot%)

Ni Co Al Mg Ni Co Al Mg
Ni-Co 3.6 4.9 30.0 61.5 4.3 6.1 29.3 60.2
6 Ni 6.8 - 27.8 65.4 7.1 - 28.9 64.0
7 Co - 9.7 30.0 61.5 - 7.8 31.2 61.0
5

100621 TPR profiles of the reducibility of Catalysts 5-7 (unreduced calcine
precipitates) are shown in Fig. 9. The reduction peaks in the range of 750 to
950 C and
for monometallic Catalyst 6 may indicate reduction of Ni in a mixed spinel
phase
NixMgi_,Al2O4. The reduction peaks in the range of 700 to 950 C for
monometallic

Catalyst 7 may indicate reduction of Co in a mixed spinet phase Co,;Mgl-
,;Al2O4. The
reduction peak in bimetallic Catalyst 5 in the range of 700 to 940 C may have
resulted
from the reduction of Ni and Co in a complex quaternary spinel-like phase. In
the
high-temperature calcination process. Ni and Co may form a continuous row of
Ni,;Co3_xO4 spinels, x > 0. The reduction peak maximum of bimetallic Catalyst
5 was at

a temperature (850 C) lower than those for Ni monometallic Catalyst 6 (868
C) and
Co monometallic Catalyst 7 (896 C). This may be attributable to the surface
enrichment of Ni and Co in Catalyst 5 because of the greater accessibility of
Ni or Co
on the catalyst surface. Also, the reduction of Catalyst 5 appeared as a
single reduction
peak, which may indicate the formation of the Ni-Co alloy during reduction.


100631 XRD analyses of the phase structure of Catalysts 5-7 (unreduced
calcined
precipitates) are shown in Fig. 10. No apparent difference was revealed
between the
XRD patterns of Catalysts 5-7. Spinel-like phases and solid solution phases
were


CA 02635312 2008-06-19
-22-

observed in all three samples. In particular, spinel-like phases with
characteristic
diffraction peaks at 20 of 30.7 , 36.8 . 44.4 , 59.8 , and 65.2 , and solid
solution phase
peaks at 20 of 41.5 and 61.2 , were observed in all samples. The spinel-like
phases may
be Ni,;Mgi-,A12O4, Co,Mgi A12O4, or their composites, which are
indistinguishable in
XRD due to their similar morphology. The solid solutions may be Ni-Mg-O and

Co-Mg-O. XRD analyses showed that all the high-temperature calcined samples
were
well-crystallized.

100641 XPS analyses of the oxidation states of surface Ni and Co in Catalysts
5-7 are
shown in Fig. 11(a) and Fig 11(b). Ni2+ (854 eV and 860 eV) was predominant in
the Ni
monometallic Catalyst 6 while Co 3+ (777 eV) was predominant in the Co
monometallic
Catalyst 7. Other oxidation states for both metals such as Ni3+ and Co2+ were
increased
in bimetallic Catalyst 5. Notably, part of the Ni shifted from a lower to a
higher

oxidation state and part of the Co shifted from a higher to a lower oxidation
state. This
indicates electron transfer between Ni and Co in bimetallic Catalyst 5. which
suggests
these metals are protected from oxidation during the reaction. It further
confirms the
near-distance interaction between Ni and Co atoms, which may easily form Ni-Co
alloy
on the bimetallic catalyst surface during reduction.

100651 Table 5 and Fig. 12 show the test results of monometallic Catalysts 6
and 7 and
bimetallic Catalyst 5 over a 28-h period. Samples were prepared by diluting
0.025 g of
catalyst with 0.475 g quartz sand. Tests were run at 750ct, 1 atm, F = 5.5
L/h. and
CH4/CO2/N2 = 1 /1 /1. Catalyst activity in terms of CH4 conversion rate (solid
line) and
CO2 conversion rate (dotted line) as functions of TOS is shown in Fig. 12.
Significant

difference did not appear in either activity or carbon deposition of
monometallic
Catalysts 6 and 7. Bimetallic Catalyst 5, on the other hand, had significantly
higher
activity and no detectable carbon deposition.



CA 02635312 2008-06-19
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Table 5: Activity and carbon deposition rate of Catalysts 5-7

Initial conversion Final conversion Average carbon
No. Catalyst (%) (%) deposition rate
CH4 CO2 CH4 CO2 (gc/ga; h )

Ni-Co 83.8 87.0 83.9 87.1 0
6 Ni 62.9 73.4 58.0 69.5 0.003186
7 Co 67.6 77.0 58.3 71.2 0.003973
EXAMPLE 6: 2000 h test of Catalyst 8 and I h test of Catalysts 9-14

5

100661 Ni-Co, Ni-Mn, Ni-Cu and Co-Mn bimetallic catalysts were prepared by
coprecipitation and designated Catalysts 8-14 respectively. Bulk metal
compositions of
the catalysts are shown in Table 6.

100671 Activity of Catalyst 8 (same as Catalyst I in terms of composition) was
tested
over a 2000-h period, and Catalysts 9-14 were tested over a 1-h period.
Catalyst 12 was
the same as Catalyst 2 in terms of composition. Samples were prepared by
diluting
catalyst with quartz sand. Tests were run at 7500C, I atm, F= 5.5 L/h, and
CH4/CO2/N2
= 1/1/1. Initial CH4 conversion, initial H2 selectivity and initial CO
selectivity, all

determined at t = 0.5 h, are shown in Table 6.


CA 02635312 2008-06-19
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Table 6: Bulk metal composition, conversion of CH4, H2 selectivity and CO
selectivity of Catalysts 8-14

Bulk Metal Composition Initial
Initial H2 Initial CO
(mol%) conversion
No. Catalyst selectivity selectivity
of CH4
Ni Co Mn Cu Al Mg (%) (%)
(%)
8 Ni-Co 6 9 - - 28 57 91.5 97.1 99.8
9 Ni-Co 4 5 - - 30 61 91.9 96.6 99.7
Ni-Co 25 9 - - 26 40 92.9 96.0 98.0
11 Ni-Co 6 27 - - 26 31 90.1 95.0 95.0
12 Ni-Mn 6 - 9 - 28 57 85.0 92.8 97.5
13 Ni-Cu 6 - - 6 30 58 53.9 82.5 92.5
14 Co-Mn 9 - 9 - 26 56 35.5 81.1 97.2

5 [0068] Fig. 13 shows the activity of Catalyst 8 in terms of the CH4
conversion and
CO2 conversion as a function of GHSV. Fig. 14 shows the activity of Catalyst 8
in
terms of the CH4 conversion and CO2 conversion as a function of reaction
temperature.
Figs. 15 and 16 show the high stability of Catalyst 8 in terms of the CH4
conversion and
CO2 conversion, respectively, as a function of TOS. Figs. 17 and 18 show the
CO

10 selectivity and H2 selectivity of Catalyst 8 as functions of TOS. As shown
in Table 6,
the selectivity of these target products is 95% or greater for all four Ni-Co
containing
catalysts (Catalysts 8-11).

Example 7: 250 h test of Catalysts 15-18

100691 Ni-Co bimetallic catalysts with varying Ni and Co content was prepared
by
coprecipitation. The catalysts were designated Catalysts 15-18. Bulk metal
compositions, BET surface area and metal dispersion of Catalysts 15-18 are
shown in


CA 02635312 2008-06-19
-25-

Table 7. Surface area was inversely related to Ni and Co content (Table 7 and
Fig. 19).
The decrease of BET surface area with the decrease of Al-Mg content provides
evidence of the stabilizing role of Al and Mg in the catalysts. Metal
dispersion was also
inversely related to Ni and Co content.


Table 7: Bulk metal composition and BET surface area of Catalysts 15-18
Bulk Metal Composition Metal
BET surface
No. Catalyst (mol%) 2 dispersion
area (m/g)
Ni Co Al Mg (%)
Ni-Co 2 3 32 63 70 11.6
16 Ni-Co 4 5 30 61 56 10.9
17 Ni-Co 6 9 28 57 45 9.7
18 Ni-Co 18 16 26 40 27 9.4

[0070] XRD analyses of the phase structure of unreduced Catalysts 15-18 are
shown
10 in Fig. 20. As in Example 5, spinel-like phases with characteristic
diffraction peaks at
of 30.7 , 36.8 , 44.4 , 59.8 , and 65.2 were observed in all samples. As Ni
and Co
content increased, increases in peak intensity were observed for the peaks of
20 = 41.5
and 61.2 , suggesting an increase in the amount of Ni-Mg-O solid solution and

Co-Mg-O solid solution. Again, all the samples under calcination at 900 C
were

15 well-crystallized. It can also be seen from the XRD patterns that the bulk
phases of the
catalysts were not altered significantly with varying Ni and Co content.

10071] TPR profiles indicating the reducibility of Catalysts 15-18 (unreduced
calcine
precipitates) are shown in Fig. 21. Fig. 21 shows a single broad reduction
peak for all
20 samples. As discussed in Example 5, after high temperature calcination, Ni
and Co may

exist in a complex structure leading to single-stage reduction with a broad
peak. Such a
structure may involve alloying of Ni and Co. Owing to the relatively low Ni-Co


CA 02635312 2008-06-19
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content, no reduction of separate Ni oxide or Co oxide was observed. Even for
the
highest Ni-Co content sample, Catalyst 18, no reduction of metal oxide was
observed.
This is consistent with the XRD analyses which did not show Ni and Co oxide
phases.
Catalyst 18 exhibited a lower temperature, broader reduction peak (650-9001)

compared to Catalyst 15-18 having lower Co and Ni content. The shift of peak
maximum to higher temperatures for the lower Ni-Co content samples may be
ascribed
to the increase of the metal-support interaction resulting from better
dispersion of Ni
and Co in the solid structures.

100721 Pore size distributions of Catalysts 15-18 are shown in Fig. 22. Pore
volume
peaks with pores having a diameter of about 30 A. As Ni-Co content increases,
the
small pores, typically having a diameter of less than 100 A, drops
significantly from
about 0.045 cm3/goat of Catalyst 15 to about 0.0075 cm3/goat of Catalyst 18.

[00731 The metal particle morphology and size distribution were investigated
using
TEM and the results are shown in Fig. 23(a)-(d). It is evident that Catalyst
18 has the
broadest distribution of metal particles with about 20 % particles larger than
10 nm
(Fig. 23(a)). As the Ni and Co content decreased, the amount of the large
metal particles
decreased significantly. AlI metal particles were smaller than 10 nm for
Catalysts 15

and 16 (Fig. 23(d) and (c)). The proportion of smaller metal particles was
increased
with the decrease in the Ni-Co content. From Catalyst 18 to Catalyst 15, the
proportion
portion of metal particles between 1 and 5 nm increased from 52 % to 76 %.
Also, in the
cases of Catalysts 15 and 16, the boundaries between metals and support became

indistinct in comparison to the boundaries observed with higher Ni-Co content
catalysts.

100741 Activity and stability of Catalysts 15-18 was investigated over a 250-h
period.
Samples were prepared by diluting 0.03 g of catalyst with 0.470 g quartz sand.
Tests
were run at 7501, 1 atm, GHSV = 180,000 mL/gcat=h and CH4/CO2/N2 = 1/1/1.
Catalyst


CA 02635312 2008-06-19
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activity in terms of CH4 conversion rate as function of TOS is shown in Fig.
24. Both
activity and stability were inversely correlated to Co and Ni content.

100751 No deactivation was observed for Catalyst 15 during the 250-h testing
period.
Catalyst 15 maintained a stable CH4 conversion rate at about 0.680 mmol/goat-
s. For
Catalyst 16, the activity increased gradually with time in the first 30 h and
then
remained at a stable CH4 conversion rate of about 0.621 mmol/goat-s.
Increasing
conversion rate during the initial period was ascribed to the formation of new
active
sites when the catalyst was exposed to the reaction mixture. Deactivation was
observed

for Catalysts 17 and 18. During the 250 h TOS, the conversion rates of CH4 for
Catalysts 17 and 18 dropped from 0.629 mmol/goat-s to 0.481 mmol/goat-s and
from
0.516 mmol/goat-s to 0.376 mmol/goat-s, respectively.

[00761 TG and DTG analysis on the spent catalysts indicated that Catalysts 15
and 16
had no detectable carbon deposition while Catalysts 17 and 18 had carbon
deposition of
up to 0.30 and 0.46 gc/gcat, respectively (Table 8, Fig. 25(a) and (b)). The
very slight
weight loss in Catalysts 15 and 16 occurring at around 1001 (Fig. 25(a))
probably
resulted from the evaporation of moisture. Carbon deposits on Catalysts 17 and
18 were
oxidized at around 420-650t (Fig. 25(a) and (b)). TEM analysis revealed no
detectable

carbon deposits on spent Catalysts 15 and 16 (Fig. 26(c) and (d)), but clear
filamentous
carbon was found on spent Catalysts 17 and 18 (Fig. 26(a) and (b)).


CA 02635312 2012-08-08
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Table 8: Carbon deposition on Catalysts 15-18

Carbon deposition at 250 h
No. Catalyst
(gc/gcat)
15 Ni-Co 0

16 Ni-Co 0
17 Ni-Co 0.300
18 Ni-Co 0.446

[0077] The scope of the claims should not be limited by the preferred
embodiments
set forth in the examples, but should be given the broadest interpretation
consistent
with the description as a whole.

Dessin représentatif
Une figure unique qui représente un dessin illustrant l'invention.
États administratifs

Pour une meilleure compréhension de l'état de la demande ou brevet qui figure sur cette page, la rubrique Mise en garde , et les descriptions de Brevet , États administratifs , Taxes périodiques et Historique des paiements devraient être consultées.

États administratifs

Titre Date
Date de délivrance prévu 2013-01-08
(22) Dépôt 2008-06-19
(41) Mise à la disponibilité du public 2009-12-19
Requête d'examen 2012-03-09
(45) Délivré 2013-01-08

Historique d'abandonnement

Il n'y a pas d'historique d'abandonnement

Taxes périodiques

Dernier paiement au montant de 473,65 $ a été reçu le 2023-06-09


 Montants des taxes pour le maintien en état à venir

Description Date Montant
Prochain paiement si taxe applicable aux petites entités 2024-06-19 253,00 $
Prochain paiement si taxe générale 2024-06-19 624,00 $

Avis : Si le paiement en totalité n'a pas été reçu au plus tard à la date indiquée, une taxe supplémentaire peut être imposée, soit une des taxes suivantes :

  • taxe de rétablissement ;
  • taxe pour paiement en souffrance ; ou
  • taxe additionnelle pour le renversement d'une péremption réputée.

Les taxes sur les brevets sont ajustées au 1er janvier de chaque année. Les montants ci-dessus sont les montants actuels s'ils sont reçus au plus tard le 31 décembre de l'année en cours.
Veuillez vous référer à la page web des taxes sur les brevets de l'OPIC pour voir tous les montants actuels des taxes.

Historique des paiements

Type de taxes Anniversaire Échéance Montant payé Date payée
Enregistrement de documents 100,00 $ 2008-06-19
Le dépôt d'une demande de brevet 400,00 $ 2008-06-19
Taxe de maintien en état - Demande - nouvelle loi 2 2010-06-21 100,00 $ 2010-04-21
Taxe de maintien en état - Demande - nouvelle loi 3 2011-06-20 100,00 $ 2011-04-29
Taxe de maintien en état - Demande - nouvelle loi 4 2012-06-19 100,00 $ 2012-02-29
Requête d'examen 800,00 $ 2012-03-09
Taxe finale 300,00 $ 2012-10-17
Taxe de maintien en état - brevet - nouvelle loi 5 2013-06-19 200,00 $ 2013-05-08
Taxe de maintien en état - brevet - nouvelle loi 6 2014-06-19 200,00 $ 2014-05-15
Taxe de maintien en état - brevet - nouvelle loi 7 2015-06-19 200,00 $ 2015-05-29
Taxe de maintien en état - brevet - nouvelle loi 8 2016-06-20 200,00 $ 2016-06-13
Taxe de maintien en état - brevet - nouvelle loi 9 2017-06-19 400,00 $ 2017-06-26
Taxe de maintien en état - brevet - nouvelle loi 10 2018-06-19 250,00 $ 2018-06-18
Taxe de maintien en état - brevet - nouvelle loi 11 2019-06-19 250,00 $ 2019-06-14
Taxe de maintien en état - brevet - nouvelle loi 12 2020-06-19 250,00 $ 2020-06-12
Taxe de maintien en état - brevet - nouvelle loi 13 2021-06-21 255,00 $ 2021-06-11
Taxe de maintien en état - brevet - nouvelle loi 14 2022-06-20 254,49 $ 2022-06-10
Taxe de maintien en état - brevet - nouvelle loi 15 2023-06-19 473,65 $ 2023-06-09
Titulaires au dossier

Les titulaires actuels et antérieures au dossier sont affichés en ordre alphabétique.

Titulaires actuels au dossier
UNIVERSITY OF SASKATCHEWAN
Titulaires antérieures au dossier
DALAI, AJAY KUMAR
WANG, HUI
ZHANG, JIANGUO
Les propriétaires antérieurs qui ne figurent pas dans la liste des « Propriétaires au dossier » apparaîtront dans d'autres documents au dossier.
Documents

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Liste des documents de brevet publiés et non publiés sur la BDBC .

Si vous avez des difficultés à accéder au contenu, veuillez communiquer avec le Centre de services à la clientèle au 1-866-997-1936, ou envoyer un courriel au Centre de service à la clientèle de l'OPIC.


Description du
Document 
Date
(yyyy-mm-dd) 
Nombre de pages   Taille de l'image (Ko) 
Abrégé 2008-06-19 1 17
Description 2008-06-19 28 975
Revendications 2008-06-19 4 89
Dessins 2008-06-19 14 191
Dessins représentatifs 2009-12-08 1 8
Page couverture 2009-12-08 1 39
Abrégé 2012-08-08 1 18
Description 2012-08-08 28 972
Revendications 2012-08-08 3 91
Page couverture 2012-12-18 2 42
Correspondance 2008-08-11 1 15
Cession 2008-06-19 6 232
Correspondance 2011-02-08 1 32
Correspondance 2011-03-08 1 15
Correspondance 2012-10-17 1 52
Poursuite-Amendment 2012-03-09 2 73
Poursuite-Amendment 2012-03-27 1 20
Correspondance 2012-03-29 1 12
Poursuite-Amendment 2012-05-11 3 108
Poursuite-Amendment 2012-08-08 11 372