Ammonia decomposition catalyst systems

Patent metadata

Field	Value
Publication number	US-12297108-B2
Application number	US-202318538049-A
Country	US
Kind code	B2
Filing date	Dec 13, 2023
Priority date	Aug 21, 2018
Publication date	May 13, 2025
Grant date	May 13, 2025

Abstract

In general, disclosed herein are methods for forming hydrogen by use of an ammonia decomposition catalyst system. For instance, a method can include contacting a catalyst system with an ammonia source at a temperature of about 450° C. or lower. The catalyst systems can include a support material and a trimetallic catalyst component carried on the support material and within a reactor. Disclosed catalyst systems can decompose ammonia at relatively low temperatures and can provide an efficient and cost-effective route to utilization of ammonia as a carbon-free hydrogen storage and generation material.

First claim

What is claimed is:

1. A method for forming hydrogen, the method comprising:
providing ammonia from an ammonia source to a first heat exchanger and pre-heating the ammonia in the first heat exchanger;
feeding the ammonia that has been pre-heated to a reactor and contacting the ammonia with an ammonia decomposition catalyst system within the reactor at a reaction temperature of about 450° C. or lower to form a reaction product comprising hydrogen, wherein the catalyst system comprises a support material and a trimetallic catalyst component carried on the support material, wherein the trimetallic catalyst component includes no more than three metals and comprises a first metal being ruthenium, a second metal selected from the group consisting of magnesium, calcium, hafnium, scandium, rhenium, strontium, and yttrium, and a promoter comprising an alkali metal, wherein the ruthenium and the second metal are present in a weight ratio to one another of from about 8:1 to about 1:8, wherein the ruthenium is present in an amount of less than 4 wt. % of the catalyst system and the promoter is present in an amount of from about 5 wt. % to about 20 wt. % of the catalyst system; and
separating the hydrogen from the reaction product using a hydrogen selective membrane fluidly connected to the catalyst system.

2. The method of claim 1 , wherein the promoter is a single metal selected from the group consisting of sodium, potassium, rubidium, and cesium.

3. The method of claim 1 , wherein the support material comprises an inorganic oxide.

4. The method of claim 1 , wherein the second metal is hafnium.

5. The method of claim 1 , wherein the second metal is yttrium.

6. The method of claim 1 , wherein the catalyst system comprises the promoter in an amount of from about 8 wt. % to about 15 wt. % of the catalyst system.

7. The method of claim 1 , wherein the catalyst system comprises the ruthenium in an amount of 3 wt. % or less.

8. The method of claim 1 , wherein the catalyst system comprises the ruthenium in an amount of 2 wt. % or less.

9. The method of claim 1 , wherein the catalyst system comprises the ruthenium in an amount of 1 wt. % or less.

10. The method of claim 1 , wherein the promoter is potassium.

11. The method of claim 1 , wherein the contacting is carried out at a pressure of from about 1 bar to about 5 bar.

12. The method of claim 1 , further comprising feeding the hydrogen from a first side of the hydrogen selective membrane to a hydrogen collection tank fluidly connected to the first side of the hydrogen selective membrane.

13. The method of claim 1 , further comprising feeding the hydrogen from a first side of the hydrogen membrane to a fuel cell fluidly connected to the first side of the hydrogen selective membrane.

14. The method of claim 1 , further comprising pre-heating the ammonia in a second heat exchanger between the ammonia source and the reactor and configured to heat the ammonia.

Assignees

• Univ South Carolina

Inventors

• Mccullough Katherine
• Lauterbach Jochen

Classifications

• C01B2203/066

  with fuel cells · CPC title

• B01J23/462

  Ruthenium · CPC title

• C01B2203/1041

  Composition of the catalyst · CPC title

• C01B2203/041

  In-situ membrane purification during hydrogen production · CPC title

• C01B2203/1094

  Promotors or activators · CPC title