Purification of gases

• US 6,511,640 B1
• Filed: 06/29/2000
• Issued: 01/28/2003
• Est. Priority Date: 06/29/2000
• Status: Expired due to Fees

• Current Assignee: BOC Group, Inc. (Messer Adolf Family)
• Original Assignee: BOC Group, Inc. (Messer Adolf Family)
• Inventors: Kumar, Ravi, Deng, Shuguang
• Primary Examiner(s): Silverman, Stanley S.
• Assistant Examiner(s): Vanoy, Timothy C.
• Application Number:
  US09/606,886
• Time in Patent Office: 943 Days
• Field of Search: 951/17, 951/29, 951/39, 951/41, 423/210, 423/230, 423/245.1, 423/247, 423/248, 423/239.1, 423/437.2
• US Class Current: 423/210
• CPC Class Codes: B01D 2253/104 Alumina
• CPC Class Codes: B01D 2253/106 Silica or silicates
• CPC Class Codes: B01D 2253/108 Zeolites
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2257/80 Water
• CPC Class Codes: B01D 2259/4146 Contiguous multilayered adsorbents
• CPC Class Codes: B01D 2259/4148 Multiple layers positioned apart from each other
• CPC Class Codes: B01D 2259/416 involving cryogenic temperature treatment
• CPC Class Codes: B01D 53/0462 Temperature swing adsorption
• CPC Class Codes: B01D 53/261 by adsorption
• CPC Class Codes: B01J 23/44 Palladium
• CPC Class Codes: B01J 23/8892 Manganese
• CPC Class Codes: C01B 21/0494 Combined chemical and physical processing
• CPC Class Codes: C01B 2210/0004 by oxidation
• CPC Class Codes: C01B 2210/0014 by adsorption in solids
• CPC Class Codes: C01B 2210/005 Carbon monoxide
• CPC Class Codes: C01B 2210/0053 Hydrogen
• CPC Class Codes: C01B 2210/0062 Water
• CPC Class Codes: F25J 2205/82 using a reactor with combustion or catalytic reaction
• CPC Class Codes: F25J 2215/44 Ultra high purity nitrogen, i.e. generally less than 1 ppb impurities
• CPC Class Codes: F25J 3/04163 : Hot end purification of the feed air arrangements of cold regenerators F25J5/00
• CPC Class Codes: F25J 3/04169 : by adsorption of the impurities adsorption in general B01D53/02
• CPC Class Codes: Y02C 20/40 : of CO2
• CPC Class Codes: Y02P 20/151 : Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Abstract

A process for producing a purified gaseous product from a gaseous feedstream such as air containing impurities is disclosed. The impurities such as hydrogen, water vapor, carbon monoxide and carbon dioxide are removed from the gaseous feedstream in a vessel having layers of adsorbents and oxidation catalysts. The placement of the hydrogen to water vapor conversion catalyst downstream of the step of contacting the feedstream with a catalyst to convert the carbon monoxide to the carbon dioxide and the step of removing the carbon dioxide from the feedstream improves not only performance but also the economies of the purification system.

Claims

1. A temperature swing adsorption process for producing a gaseous product substantially purified from impurities comprising

a) removing water vapor from a gaseous feedstream containing impurities;

b) contacting said gaseous feedstream with an oxidation catalyst to convert carbon monoxide to carbon dioxide;

c) removing carbon dioxide from said gaseous feedstream of steps (a) and (b);

d) contacting said gaseous feedstream of step (c) with an oxidation catalyst to convert hydrogen to water vapor; and

e) removing water vapor from said gaseous feedstream of step (d), thereby obtaining said substantially purified gaseous product.

2. The process as claimed in claim 1 wherein said gaseous feedstream is air.

3. The process as claimed in claim 1 wherein said impurities are selected from the group consisting of hydrogen, water vapor, carbon monoxide and carbon dioxide.

4. The process as claimed in claim 1 wherein step (a) comprises contacting said gaseous feed stream with a water vapor removing adsorbent.

6. The process as claimed in claim 1 wherein said oxidation catalyst of step (b) is a mixture of manganese and copper oxides.

7. The process as claimed in claim 1 wherein step (c) comprises contacting said gaseous feedstream with a carbon dioxide removing adsorbent.

8. The process as claimed in claim 7 wherein said carbon dioxide removing adsorbent is selected from the group consisting of zeolites, activated alumina, silica gel and combinations thereof.

9. The process as claimed in claim 1 wherein said oxidation catalyst of step (d) is a noble metal catalyst.

10. The process as claimed in claim 9 wherein said noble metal catalyst is supported palladium.

11. The process as claimed in claim 1 wherein step (e) comprises contacting said gaseous feedstream with a water vapor removing adsorbent.

12. The process as claimed in claim 11 wherein said water vapor removing adsorbent is selected from the group consisting of activated alumina, silica gel, zeolites and combinations thereof.

13. The process as claimed in claim 1 further comprising contacting said gaseous feedstream with an adsorbent to remove hydrocarbons and oxides of nitrogen.

14. The process as claimed in claim 1 further comprising the step of cryogenically separating the components of step (e).

15. The process as claimed in claim 1 wherein the regeneration gas for the thermal swing adsorption process is free of H₂, CO, CO₂, H₂O, oxides of nitrogen and hydrocarbons and is obtained from a cryogenic separation unit.

5. The process as claimed 4 in claim wherein said water vapor removing adsorbent is selected from the group consisting of activated alumina, silica gel, zeolites and combinations thereof.