Catalyst for high temperature steam reforming

Patent metadata

Field	Value
Publication number	US-10010876-B2
Application number	US-201615359986-A
Country	US
Kind code	B2
Filing date	Nov 23, 2016
Priority date	Nov 23, 2016
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

This invention relates to highly active and stable catalyst composite used in high temperature synthesis gas production. More specifically, nickel alumina catalysts doped with noble metals and lanthanide groups or transition metal groups containing a lattice spinel structure with a general formula [Ni x A 1-x ][(B y Al 1-y ) 2 ]O 4 . Stabilizers such as yttria-stabilized zirconia are also integrated in this composite to enhance high temperature catalytic performance. The catalyst composite of present invention exhibits high redox tolerance, coking resistance, high temperature stability, and high catalytic activity.

First claim

We claim:

1. A Ni/spinel catalyst composite for reforming hydrocarbons comprising a spinel lattice structure, said structure of formula I:
[Ni x A 1-x ][B y (Al) 1-y ] 2 O 4   (I)

wherein
A is a first metal dopant which is a precious metal dopant selected from Pt, Rh, Ru, Ir, Pd, and Au;
x is greater than zero but less than 1.0;
B is a second metal dopant selected from the lanthanide series or the transition metals;
y is greater than zero but less than about 0.1;

wherein the Ni of said composite is part of the lattice structure of said spinel, as determined by the absence of XRD peak intensity at 44.5°±0.3° and at 43.5°±0.3° for Ni and NiO, respectively,
and wherein the peak intensity ratio (Idopant-oxide/Ispinel) is less than 0.9.

2. The catalyst of claim 1 , wherein the second metal dopant (B) is part of the spinel lattice structure as indicated by the absence of the XRD peak corresponding to the oxide of the second metal dopant.

3. The catalyst of claim 1 , wherein the second metal dopant (B) is Ce, and the peak intensity ratio of I CeO2 (2-theta of 28.7°) to I spinel (2-theta of 37.2°) is less than 0.9.

4. The catalyst of claim 1 , wherein the active metal Ni is part of the spinel lattice structure of formula I and the peak intensity ratio of the Bragg's angle 2-theta of 37.2° to the Bragg's angle 2-theta of 65.7° is less than 2.0.

5. The catalyst claim 1 , wherein said second metal dopant B is selected from the group consisting of La, Ce, Ti, V, Cr, Mn, Fe, Co, Cu, Y, Zr and mixtures thereof.

6. The catalyst of claim 5 , wherein said second metal dopant is derived from one or more of water soluble metal salts in form of a nitrate, chloride, acetate, oxalate, halide, sulfate and/or a hydrate thereof.

7. The catalyst of claim 5 , wherein the first metal dopant (A) is Pt, Rh, and/or Ru and the second metal dopant (B) is Ce.

8. The catalyst of claim 1 , wherein the Ni is present in an amount of about 5 wt % to about 33 wt % based on a total weight of the catalyst.

9. The catalyst of claim 1 which, when calcined at a temperature≥900° C., has a BET surface area of greater than 70 m 2 /g.

10. The catalyst of claim 9 which, when calcined at a temperature≥750° C., has a BET surface area of greater than 85 m 2 /g.

11. The catalyst of claim 1 , wherein the atomic ratio of said second metal dopant (B) to Al ranges from about 0.1:99.9 to about 10:90.

12. The catalyst of claim 11 , wherein the atomic ratio of said second metal dopant (B) to Al ranges from about 0.5:99.5 to about 6:94.

13. The catalyst of claim 1 , wherein the atomic ratio of said second metal dopant (B) to Al is greater than zero, but less than about 4:96.

14. The catalyst of claim 1 , wherein said catalyst contains less than about 1.0 wt % of oxides of said second metal dopant, as measured by XRD peak intensity analysis.

15. The catalyst of claim 14 , wherein said catalyst contains substantially no oxides of said second metal dopant, as measured by XRD peak intensity analysis.

16. The catalyst of claim 1 , wherein said catalyst has an average retained crystallite size of 10 nm or less after calcining at 850° C.

17. The catalyst of claim 1 , wherein said catalyst has an average retained crystallite size of 5 nm or less after calcining at 850° C.

18. The catalyst composite of claim 1 , which comprises an optional stabilizer M, wherein M is high temperature stabilizer composite oxide selected from the group consisting of YSZ, stabilized Al 2 O 3 , BaO, CaO, La 2 O 3 , ceria stabilized zirconia, Sm 2 O 3 , perovskite, hexaaluminate, pyrochlore, hydrotalcite, and mixtures thereof.

19. The catalyst of claim 18 , wherein the stabilizer M is YSZ and is present in an amount of less than about 10 wt % of the catalyst composite.

20. A method of manufacturing a catalyst composite according to claim 1 for reforming hydrocarbons wherein said catalyst comprises a catalytically active amount of nickel within a spinel lattice structure, said method comprising:
a) Mixing of salts of nickel, a first metal dopant (A), aluminum, and a second metal dopant (B) either by wet dissolving in solvent or drying mixing together;
b) Aging the mixture prepared in step a) by either adjusting solvent pH value to about 2 to about 5, or by co-precipitation process, or by thermal treatment of salts at temperature ranged from 100 to 350° C.;
c) Forming either viscous gel mixture by vaporizing solvents, precipitation substance, or metal salt melt; and
d) Calcining the mixture of step c) in an oxygen environment at a temperature of from about 750 to 1200° C.,

wherein
said first metal dopant (A) is a precious metal dopant selected from a group consisting of Pt, Rh, Ru, Ir, Pd, and Au,
said second metal dopant (B) is selected from trivalent cations of La, Ce, Ti, V, Cr, Mn, Fe, Co, Cu, Y, Zr or mixtures thereof,
the atomic ratio of said second metal dopant (B) to Al is greater than zero up to about 10:90.

21. The method of claim 20 wherein, said calcining is performed by combustion synthesis, flame spray pyrolysis, plasma spray, or electrically-heated furnace calcination.

22. The method of claim 20 wherein, the atomic ratio of said second metal dopant (B) to Al is in a range of from about 0.5:99.5 to about 6:94.

23. The method of claim 20 wherein, nickel is present in the final catalyst composition in an amount of from about 5 wt % to about 33 wt %, based on the total weight of the catalyst.

24. The method of claim 20 wherein, step a), the water soluble salts of said Ni, said first metal dopant (A), aluminum and said second metal dopant (B) are selected from one or more of nitrate salts, chloride salts, acetate salts, oxalate salts, halide salts, sulfate salts and/or a hydrate thereof.

25. The method of claim 20 wherein, in step b), the aqueous solution is heated to a temperature of from about 80° C. to about 100° C.

26. The method of claim 20 wherein, said calcining step is accomplished by combustion synthesis and the combustion fuel is urea, glycine, ethylene glycol, or mixtures thereof.

27. The method of claim 20 wherein, sol-gel is calcined in an atmosphere of air or oxygen containing gas at a temperature of from about 700 to about 1000° C.

28. The method of claim 20 which comprises:
a) Dissolving Ni nitrate, aluminum nitrate, rhodium nitrate and cerium nitrate in deionized water to provide an aqueous solution, while controlling pH to be in a range of from about 2 to about 5;
b) Heating the aqueous solution to a temperature of from about 80° C. to about 100° C.;
c) Adding a combustion fuel to the aqueous solution, and increasing the temperature effective to vaporize the water contained in the mixture and to form the viscous sol-gel; and
d) Calcining the sol-gel at a temperature of from about 700 to about 1000° C. to obtain the final catalyst powder,

wherein the atomic ratio of Ce to Al is greater than zero, but less than about 6:94.

29. The method of claim 28 wherein, said combustion fuel is urea, glycine, ethylene glycol, or mixtures thereof.

Assignees

• Lin Jiefeng
• Christie Gervase Maxwell
• Praxair Technology Inc

Inventors

• Lin Jiefeng
• Christie Gervase Maxwell

Classifications

• B01J37/08

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

• B01J35/1019

  Operations & Transport · mapped topic

• B01J37/04

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

• B01J35/1014

  Operations & Transport · mapped topic

• B01J35/1028

  Operations & Transport · mapped topic