Purification of a mixture of H2/CO by catalysis of the NOx

• US 7,588,742 B2
• Filed: 06/10/2004
• Issued: 09/15/2009
• Est. Priority Date: 06/10/2004
• Status: Active Grant

• Current Assignee: L'Air Liquide SA
• Original Assignee: L'Air Liquide Societe Anonyme Pour L'Etude et L'Exploitation Des Procedes Georges Claude (L'Air Liquide SA)
• Inventors: Haik-Beraud, Natacha, Moulin, Audrey, Jantet, Francois, Moreau, Serge
• Primary Examiner(s): Vanoy; Timothy C
• Application Number:
  US10/559,138
• Publication Number:
  US 20070274891A1
• Time in Patent Office: 1,923 Days
• Field of Search: 423/239.1, 423/418.2, 423/648.1, 252/373
• US Class Current: 423/239.1
• CPC Class Codes: B01D 2255/1023 Palladium
• CPC Class Codes: B01D 2255/20761 Copper
• CPC Class Codes: B01D 2257/406 Ammonia
• CPC Class Codes: B01D 2257/80 Water
• CPC Class Codes: B01D 53/75 Multi-step processes
• CPC Class Codes: B01D 53/8628 Processes characterised by a specific catalyst
• CPC Class Codes: B01J 23/44 Palladium
• CPC Class Codes: B01J 23/72 Copper
• CPC Class Codes: B01J 23/868 copper and chromium
• CPC Class Codes: C01B 21/02 Preparation of nitrogen by decomposition of ammonia C01B3/047
• CPC Class Codes: C01B 2203/042 Purification by adsorption on solids
• CPC Class Codes: C01B 2203/043 Regenerative adsorption process in two or more beds, one for adsorption, the other for regeneration
• CPC Class Codes: C01B 2203/0435 Catalytic purification
• CPC Class Codes: C01B 2203/0465 Composition of the impurity
• CPC Class Codes: C01B 2203/0495 the impurity being water
• CPC Class Codes: C01B 3/56 by contacting with solids; Regeneration of used solids C01B3/508 takes precedence
• CPC Class Codes: C01B 3/58 including a catalytic reaction
• CPC Class Codes: C01C 1/04 Preparation of ammonia by synthesis in the gas phasepreparation or purification of gas mixtures for ammonia synthesis C01B3/025
• CPC Class Codes: Y02P 20/52 using catalysts, e.g. selective catalysts

Abstract

The invention relates to a method for purifying a gas flow containing hydrogen (H2) and carbon monoxide (CO), in addition to at least one nitrogen oxide (NOx), as impurities. According to said method, the gaseous flow is brought into contact with at least one catalyst containing copper and/or palladium, at a temperature between 100 DEG C. and 200 DEG C., in such a way as to eliminate at least part of the nitrogen oxide.

Claims

1. A method for purifying a gas stream containing hydrogen (H₂) and carbon monoxide (CO), and further containing at least one nitrogen oxide (NOx) as impurities, in which the gas stream is contacted with at least one catalyst containing copper and/or palladium, at a temperature of between 100°

C. and 200°

C., in order to remove at least part of the nitrogen oxide, wherein the catalyst is protected by at least one protective bed located upstream of said catalyst.

2. The method of claim 1, characterized in that the temperature is between 120°

C. and 180°

C. and/or the pressure is between 10 and 80 bar.

3. The method of claim 1, characterized in that the Gas Hourly Space Velocity (GHSV) is between 1000 and 10 000 Sm³/h of gas/m³ of catalyst.

4. The method of claim 1, characterized in that the gas stream is contacted with the catalyst containing copper.

5. The method of claim 1, characterized in that the gas stream contains hydrogen (H₂), carbon monoxide (CO), and methane (CH₄).

6. The method of claim 1, characterized in that the nitrogen oxides are converted to water (H₂), O₂, NH₃, and/or N₂.

7. The method of claim 6, characterized in that the water (H₂) and NH₃ resulting from the catalysis of the NOx are removed by means of one or more adsorption steps.

8. The method of claim 7, characterized in that at least one adsorption step is carried out using one or more adsorbents selected from the group formed by zeolites, exchanged or not, activated aluminas, silica gels, or mixtures or combinations thereof.

9. The method of claim 1, characterized in that the gas stream to be separated contains 10% by volume to 90% by volume of H₂, 10% by volume to 90% by volume of CO and, optionally, methane.

10. The method of claim 1, characterized in that the temperature is between 120°

C. and 180°

C. and/or the pressure is between about 20 to 50 bar.

11. The method of claim 1, characterized in that the Gas Hourly Space Velocity (GHSV) is between 2000 and 6000 Sm³/h of gas/m³ of catalyst.