CATALYSTS FOR OXIDATIVE COUPLING OF METHANE AND SOLUTION COMBUSTION METHOD FOR THE PRODUCTION OF THE SAME

• US 20140080699A1
• Filed: 08/20/2013
• Published: 03/20/2014
• Est. Priority Date: 08/20/2012
• Status: Active Grant

• Current Assignee: Purdue Research Foundation (The Trustees of Purdue University (d/b/a Purdue University))
• Original Assignee: Purdue Research Foundation (The Trustees of Purdue University (d/b/a Purdue University))
• Inventors: Varma, Arvind, Ghose, Ranjita, Hwang, Hyun Tae
• Granted Patent: US 9,610,565 B2
• Time in Patent Office: Days
• US Class Current: 502/241
• CPC Class Codes: B01J 23/005 Spinels
• CPC Class Codes: B01J 23/02 of the alkali- or alkaline earth metals or beryllium
• CPC Class Codes: B01J 23/10 of rare earths
• CPC Class Codes: B01J 23/28 Molybdenum
• CPC Class Codes: B01J 23/34 Manganese
• CPC Class Codes: B01J 23/85 Chromium, molybdenum or tungsten
• CPC Class Codes: B01J 2523/00 Constitutive chemical elements of heterogeneous catalysts
• CPC Class Codes: B01J 2523/12 Sodium
• CPC Class Codes: B01J 2523/24 Strontium
• CPC Class Codes: B01J 2523/31 Aluminium
• CPC Class Codes: B01J 2523/3706 Lanthanum
• CPC Class Codes: B01J 2523/41 Silicon
• CPC Class Codes: B01J 2523/69 Tungsten
• CPC Class Codes: B01J 2523/72 Manganese
• CPC Class Codes: B01J 35/002 Catalysts characterised by their physical properties
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 37/04 Mixing B01J37/0009, B01J37/0018 take precedence
• CPC Class Codes: B01J 37/088 Decomposition of a metal salt
• CPC Class Codes: C01F 11/04 by thermal decomposition
• CPC Class Codes: C01F 17/229 Lanthanum oxides or hydroxides
• CPC Class Codes: C01F 17/34 : Aluminates, e.g. YAlO3 or Y3-xGdxAl5O12
• CPC Class Codes: C01F 7/166 : Strontium aluminates
• CPC Class Codes: C01G 41/02 : Oxides; Hydroxides
• CPC Class Codes: C01P 2002/72 : by d-values or two theta-values, e.g. as X-ray diagram

Abstract

A method for making a metal oxide material and catalyzing the oxidative coupling of methane, including mixing a metal cation-containing oxidizer portion and a reducing fuel portion with water to define an aqueous solution, evaporatively removing water from the aqueous solution to yield a concentrated liquid, burning the concentrated liquid yield an homogeneous metal oxide powder, flowing methane from a first source and oxygen from a second source over the homogeneous metal oxide powder, and catalyzing an oxidative coupling of methane reaction with the homogeneous metal oxide powder. The homogeneous metal oxide powder contains metal oxides selected from the group including LaSrAlO₄, LaAlO₃, Sr₃Al₂O₆, Na₂WO₄—Mn/SiO₂, and combinations thereof.

Claims

1. A method for producing metal oxide catalysts for oxidative coupling of methane reactions, comprising:

measuring predetermined stoichiometric amounts of metal cation contributors to define a predetermined metal cation precursor;

measuring a predetermined amount of reducing fuel;

mixing the predetermined amount of fuel, the predetermined metal cation precursor and water to define an aqueous solution;

evaporating water from the aqueous solution to define a concentrated solution;

igniting the concentrated solution;

combustively reacting the metal cation precursor with the fuel to yield a metal oxide

2. The method of claim 1 wherein metal cation containing portion contains members of the group comprising lanthanum nitrate hexahydrate, strontium nitrate, aluminum nitrate nonahydrate, sodium tungsten oxide dehydrate, manganese nitrate tetrahydrate, tetraethoxysilane, and combinations thereof, and wherein the reducing fuel is glycine, hydrazine, oxalates, citric acid etc and combinations thereof.

3. The method of claim 1 and further comprising:

flowing methane from a first source over the metal oxide;

flowing oxygen from a second source over the metal oxide;

mixing methane from the first source with oxygen from the second source in the presence of the metal oxide; and

catalyzing an oxidative coupling of methane reaction with the metal oxide.

15. The method of claim 1, and further comprising:

dissolving solids into the aqueous solution;

evaporating the concentrated solution to yield a paste; and

self-igniting the paste.

4. A method for making a metal oxide material, comprising:

mixing a metal cation-containing oxidizer portion and a reducing fuel portion with water to define an aqueous solution;

evaporatively removing water from the aqueous solution to yield a concentrated liquid;

burning the concentrated liquid yield an homogeneous metal oxide powder;

flowing methane from a first source and oxygen from a second source over the homogeneous metal oxide powder; and

catalyzing an oxidative coupling of methane reaction with the homogeneous metal oxide powder;

wherein the homogeneous metal oxide powder contains metal oxides selected from the group including LaSrAlO₄, LaAlO₃, Sr₃Al₂O₆, Na₂WO₄—

Mn/SiO₂, and combinations thereof.

5. The method of claim 4 wherein metal cation containing portion contains members of the group comprising lanthanum nitrate hexahydrate, strontium nitrate, aluminum nitrate nonahydrate, sodium tungsten oxide dehydrate, manganese nitrate tetrahydrate, tetraethoxysilane, and combinations thereof, and wherein the oxidizing fuel portion is selected from the group including glycine, hydrazine, oxalates, citric acid, and combinations thereof.

6. The method of claim 4 wherein the reducing fuel portion to metal-cation containing oxidizer portion ratio is between 0.5 and 2.0.

14. The method of claim 4, and further comprising:

before evaporatively removing water from the aqueous solution to yield a concentrated liquid and after mixing a metal cation-containing oxidizer portion and a reducing fuel portion with water to define an aqueous solution, dissolution of solids into aqueous solution;

wherein the metal cation-containing oxidizing precursor is of the form M_x(NO₃)_y•

zH₂O;

wherein the metal cation-containing oxidizing precursor is added in proportions desired in the metal oxide powder;

wherein M is selected from the group comprising Al, Sr, La, and Na;

wherein during evaporatively removing water from the aqueous solution to yield a concentrated liquid, the heating rate is between 1 degree Celsius per minute and 50 degrees Celsius per minute;

wherein the concentrated liquid is a paste;

wherein burning the liquid occurs through self-ignition of the paste; and

wherein burning the liquid includes calcining at temperatures between about 600 degrees Celsius and 1000 degrees Celsius to yield a metal oxide powder.

7. A method for preparing a metal oxide material for the catalysis of oxidative coupling of methane, comprising:

mixing a metal cation-containing oxidizing precursor and an reducing fuel with water to yield an aqueous solution;

heating the aqueous solution to evaporate at least some of the water to define a concentrated liquid precursor;

igniting the concentrated liquid precursor to remove gasses to yield a char portion; and

fully combusting the char portion to yield an homogeneous powder portion;

wherein the homogeneous powder portion is a metal oxide powder;

wherein the metal cations are selected from the group including Al, Sr, La, Na, W, Mn, and Si; and

wherein the metal oxides are selected from the group including LaSrAlO₄, LaAlO₃, Sr₃Al₂O₆, Na₂WO₄—

Mn/SiO₂ and combinations thereof.

8. The method of claim 7 wherein the reducing fuel to metal-cation containing oxidizer precursor ratio is between 0.5 and 2.0.

9. The method of claim 7 wherein the gasses are members of the group consisting of CO, CO₂, H₂O, N₂ and combinations thereof.

10. The method of claim 7 wherein metal cation containing oxidizing portion contains members of the group comprising lanthanum nitrate hexahydrate, strontium nitrate, aluminum nitrate nonahydrate, sodium tungsten oxide dehydrate, manganese nitrate tetrahydrate, tetraethoxysilane, and combinations thereof, and wherein the reducing fuel is glycine.

12. The catalyst of claim 10 wherein the Na₂WO₄ and Mn/SiO₂ are present primarily as Mn₂O₃, Na₂WO₄ and α

-cristobalite structured SiO₂ phases.

13. The method of claim 7 wherein the metal cation-containing oxidizing precursor is of the form M_x(NO₃)_y•

zH₂O;

wherein the metal cation-containing oxidizing precursor is added in proportions desired in the metal oxide powder;

wherein M is selected from the group comprising Al, Sr, La, and Na;

wherein during heating the aqueous solution to evaporate at least some of the water to define a concentrated liquid precursor, the heating rate is between 1 degree Celsius per minute and 50 degrees Celsius per minute;

wherein the concentrated liquid precursor is a paste;

wherein fully combusting the char portion to yield an homogeneous powder portion occurs through self-ignition of the concentrated liquid precursor; and

wherein the char portion is calcined at temperatures between about 600 degrees Celsius and 1000 degrees Celsius to yield a metal oxide powder.

11. A catalyst for the oxidative coupling of methane, comprising:

about 10 weight percent Na₂WO₄; and

about 5 weight percent Mn/SiO₂.