Catalysts for the reforming of gaseous mixtures

Patent metadata

Field	Value
Publication number	US-11673123-B2
Application number	US-201816493616-A
Country	US
Kind code	B2
Filing date	Mar 12, 2018
Priority date	Mar 14, 2017
Publication date	Jun 13, 2023
Grant date	Jun 13, 2023

Abstract

Pyrochlore-based solid mixed oxide materials suitable for use in catalysing a hydrocarbon reforming reaction are disclosed, as well as methods of preparing the materials, and their uses in hydrocarbon reforming processes. The materials contain a catalytic quantity of inexpensive nickel and exhibit catalytic properties in dry reforming reactions that are comparable—if not better—than those observed using expensive noble metal-containing catalysts. Moreover, the Pyrochlore-based solid mixed oxide materials can be used in low temperature dry reforming reactions, where other catalysts would become deactivated due to coking. Accordingly, the catalytic materials represent a sizeable development in the industrial-scale reforming of hydrocarbons.

First claim

The invention claimed is:

1. A solid mixed oxide material suitable for use in catalysing a methane dry reforming reaction, wherein the solid mixed oxide material comprises a first crystalline phase, the first crystalline phase being attributable to a pyrochlore crystal structure, and wherein the solid mixed oxide material comprises 7.5-13.0% of nickel by weight relative to a total weight of the solid mixed oxide material, and wherein the first crystalline phase has a composition according to general formula (I) shown below
A 2 B 2 O 7    (I)

wherein:
A is a trivalent cation of La, and optionally one or more other trivalent cation of an element selected from the group consisting of Ce, Pr, Nd, Sm, Sc, Y and Eu; and
B is a mixture of:
(i) a tetravalent cation of Zr, and optionally one or more other tetravalent or trivalent cation of an element selected from the group consisting of Ti, Cr, Mn and Mo, and
(ii) a divalent cation of Ni,

and wherein the solid mixed oxide material comprises a second crystalline phase, the second crystalline phase being attributable to a Ruddlesden-Popper crystal structure of general formula (II) shown below:
A′ 2 B′O 4    (II)

wherein:
A′ is a trivalent cation of La, and optionally one or more other trivalent cation of an element selected from the group consisting of Ce, Pr, Nd, Sm, Sc, Y and Eu; and
B′ is a divalent cation of Ni, and optionally one or more other divalent, trivalent or tetravalent cations of an element selected from the group consisting of Fe, Co, Cu, Ti and Zr;

wherein the solid mixed oxide material has a surface area of 9-14 m 2 /g, a pore volume of 0.06-0.13 cm 3 /g and an average pore size of 3.5-5.5 nm.

2. The solid mixed oxide material of claim 1 , wherein the solid mixed oxide material comprises 9.5-13.0% of nickel by weight relative to the total weight of the solid mixed oxide material.

3. The solid mixed oxide material of claim 1 , wherein:
A is a trivalent cation of La; and
B is a mixture of:
i. a tetravalent cation of Zr, and
ii. a divalent cation of Ni.

4. The solid mixed oxide material of claim 1 , wherein
the solid mixed oxide material comprises 15.0-35.0% of zirconium by weight relative to the total weight of the solid mixed oxide material, and/or
the solid mixed oxide material comprises 48.0-60.0% of lanthanum by weight relative to the total weight of the solid mixed oxide material.

5. The solid mixed oxide material of claim 1 , wherein
the solid mixed oxide material is in a form of a powder, pellet or foam, and/or
the solid mixed oxide material is self-supported.

6. The solid mixed oxide material of claim 1 , wherein: A′ is a trivalent cation of La, and B′ is a divalent cation of Ni, and optionally a tetravalent cation of Zr.

7. The solid mixed oxide material of claim 1 , wherein the solid mixed oxide material further comprises 0.001-0.5% of at least one promoter by weight relative to the total weight of the solid mixed oxide material, and wherein the at least one promoter is selected from the group consisting of Sn, Ba, Ca, Mg, Ce, Sr, K, Pt, Rh, Pd, Mo, Ag, Au, Ru, Zn, Cu, Co and Ir.

8. A process for the preparation of the solid mixed oxide material as claimed in claim 1 , said process comprising steps of:
a) providing a mixture comprising
i. at least one solvent;
ii. metal precursors, respective amounts of the metal precursors being sufficient to form a pyrochlore crystalline phase in the solid mixed oxide material resulting from step c), and
iii. at least one chelating agent;

b) drying the mixture of step a); and
c) thermally treating a solid material resulting from step b) at a temperature greater than 800° C.,

wherein at least one of the metal precursors mixed in step a) is a nickel precursor in an amount sufficient to provide a nickel content in the solid mixed oxide material resulting from step c) of 3.5-25.0% by weight relative to a total weight of the solid mixed oxide material.

9. The process of claim 8 , wherein the at least one solvent is selected from the group consisting of water, methanol, ethanol and acetone.

10. The process of claim 8 , wherein the at least one chelating agent is selected from the group consisting of citric acid, ethylenediaminetetraacetic acid (EDTA), disodium EDTA, trisodium EDTA, ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid (EGTA) and succinic acid.

11. The process of claim 8 , wherein the mixture of step a) comprises at least one chelating agent in an amount sufficient to give a molar ratio of total chelating agent to metal in the mixture of (0.3-1.0):1.

12. The process of claim 8 , wherein step c) comprises thermally treating the solid material resulting from step b) at a temperature of 800-1500° C.

13. The process of claim 8 , wherein step c) is performed for 4-24 hours.

14. The process of claim 8 , wherein the mixture provided in step a) further comprises:
iv. at least one Sn, Ba, Ca, Mg, Ce, Sr, K, Pt, Rh, Pd, Mo, Ag, Au, Ru, Zn, Cu, Co or Ir-based promoter precursor in an amount sufficient to provide a promoter content in the solid mixed oxide material resulting from step c) of 0.001-0.5% by weight relative to the total weight of the solid mixed oxide material.

15. A reduced or partially-reduced solid mixed oxide material, wherein the reduced or partially-reduced solid mixed oxide material is a reduced or partially-reduced form of the solid mixed oxide material as claimed in claim 1 .

16. A process for catalytically reforming a gaseous mixture, said process comprising a step of:
a) contacting a gaseous mixture comprising CO 2 and CH 4 with either or both of:
i. the solid mixed oxide material as claimed in claim 1 , and
ii. a reduced or partially-reduced solid mixed oxide material wherein the reduced or partially-reduced solid mixed oxide material is a reduced or partially-reduced form of the solid mixed oxide material as claimed in claim 1 ,

wherein step a) is conducted at a temperature of 500-1000° C.

17. The process of claim 16 , wherein step a) is conducted at a temperature of 550-850° C.

18. The process of claim 16 , wherein step a) is conducted at a space velocity (WHSV) of 10-120 Lg −1 h −1 .

19. The process of claim 16 , wherein the process is a dry reforming, bi-reforming or tri-reforming process, or a combination of two or more thereof.

Assignees

• Univ Surrey
• Univ Of Alicante

Inventors

• Ramirez Reina Tomas
• Le Saché Estelle
• Gu sai
• Watson David
• Pastor Pérez Laura
• Sepúlveda Escribano Antonio

Classifications

• B01J23/002

  Mixed oxides other than spinels, e.g. perovskite · CPC title

• B01J37/08

  Heat treatment {(B01J37/0009, B01J37/0018 take precedence)} · CPC title

• C01P2002/36

  pyrochlore-type (A2B2O7) · CPC title

• C01B2203/1241

  Natural gas or methane · CPC title

• C01B3/40

  characterised by the catalyst · CPC title