Catalyst for decomposition of sulfur trioxide and hydrogen production process

Patent metadata

Field	Value
Publication number	US-8940270-B2
Application number	US-201113997473-A
Country	US
Kind code	B2
Filing date	Dec 27, 2011
Priority date	Dec 28, 2010
Publication date	Jan 27, 2015
Grant date	Jan 27, 2015

Abstract

To provide a sulfur trioxide decomposition catalyst, particularly, a sulfur trioxide decomposition catalyst capable of lowering the temperature required when producing hydrogen by an S—I cycle process.
A sulfur trioxide decomposition catalyst comprising a composite oxide of vanadium and at least one metal selected from the group consisting of transition metal and rare earth elements is provided. Also, a sulfur dioxide production process comprising decomposing sulfur trioxide into sulfur dioxide and oxygen by using the sulfur trioxide decomposition catalyst above, is provided. Furthermore, a hydrogen production process, wherein the reaction of decomposing sulfur trioxide into sulfur dioxide and oxygen by an S—I cycle process is performed by the above-described sulfur dioxide production process, is provided.

First claim

The invention claimed is:

1. A sulfur dioxide production process, comprising decomposing sulfur trioxide into sulfur dioxide and oxygen with a sulfur trioxide decomposition catalyst, wherein the sulfur trioxide decomposition catalyst comprises a composite oxide of vanadium and at least one metal selected from the group consisting of transition metal and rare earth elements.

2. The process as claimed in claim 1 , wherein said at least one metal is selected from the group consisting of copper (Cu), chromium (Cr), titanium (Ti), zirconium (Zr), lanthanum (La), cerium (Ce), neodymium (Nd) and a combination thereof.

3. The process as claimed in claim 1 , wherein in said composite oxide, the atom ratio between said at least one metal and vanadium is from 1:9 to 9:1.

4. The process as claimed in claim 1 , wherein said at least one metal is cerium (Ce), and in said composite oxide, the atom ratio (cerium:vanadium) between cerium and vanadium is from 0.4:1 to less than 1:1.

5. The process as claimed in claim 4 , wherein in said composite oxide, the atom ratio (cerium:vanadium) between cerium and vanadium is from 0.8:1 to 0.95:1.

6. The process as claimed in claim 1 , wherein said composite oxide is supported on a support.

7. The process as claimed in claim 6 , wherein said support is selected from the group consisting of silica, alumina, zirconia, titania and a combination thereof.

8. The process as claimed in claim 7 , wherein said support is a porous silica support having a pore structure.

9. The process as claimed in claim 1 , wherein said decomposition is performed at a temperature of 800° C. or less.

10. The process as claimed in claim 1 , wherein said decomposition is performed at a temperature of 700° C. or less.

11. A hydrogen production process comprising splitting water into hydrogen and oxygen, wherein the process comprises decomposing sulfuric acid into water, sulfur dioxide and oxygen through a reaction represented by the following formula (X1) and out of the elementary reactions represented by the following formulae (X1-1) and (X1-2), which are elementary reactions of the reaction represented by the following formula (X1), the elementary reaction of formula (X1-2) being performed by the process claimed in claim 1 :
H 2 SO 4 →H 2 O+SO 2 +½O 2   (X1)

H 2 SO 4 →H 2 O+SO 3   (X1-1)

SO 3 →SO 2 +½O 2 .  (X1-2)

12. The hydrogen production process as claimed in claim 11 , wherein the hydrogen production process is an S—I cycle process, a Westinghouse cycle process, an Ispra-Mark 13 cycle process, or a Los Alamos science laboratory cycle process.

Assignees

• Takeshima Shinichi
• Machida Masato
• Toyota Motor Co Ltd
• Univ Kumamoto Nat Univ Corp

Inventors

• Takeshima Shinichi
• Machida Masato

Classifications

• C01B3/103

  the hydrogen being generated from the water as a result of cycles of reactions, e.g. sulfur-iodine cycle · CPC title

• B01J2235/15

  X-ray diffraction · CPC title

• B01J23/22

  Vanadium · CPC title

• B01J37/0205

  in several steps · CPC title

• Y02E60/36

  Hydrogen production from non-carbon containing sources, e.g. by water electrolysis · CPC title