Process for removing oxygen from a hydrogen stream
A pressure swing adsorption process is provided to remove oxygen from a hydrogen stream through the use of a copper material in combination with layers of adsorbent to remove water, C2 and C3 hydrocarbons, as well as other impurities. The feed gas comprises more than 70 mol % hydrogen, at least 1 mol % methane and more than 10 ppmv oxygen. The purified product hydrogen stream comprises greater than 99 mol % hydrogen, with less than 1 ppmv oxygen.
1. A process for producing a high-purity hydrogen gas stream from a feed stream comprising hydrogen, hydrocarbons, and oxygen, said process comprising sending said feed stream through an adsorbent bed comprising a copper material at a pressure greater than about 4 bar(g) to remove said oxygen from said feed stream, and then purging said adsorbent bed in a counter-current direction with a hydrogen-rich gas at a pressure less than about 1 bar(g).
2. The process of claim 1 wherein said feed stream is passed through said adsorbent bed at a temperature less than about 60° C.
3. The process of claim 1 wherein said during purging of said adsorbent bed said hydrogen-rich gas has a temperature of less than about 60° C.
4. The process of claim 1 , wherein said feed stream comprises more than 70 mol % hydrogen.
5. The process of claim 1 , wherein said feed stream comprises more than 1 mol % methane.
6. The process of claim 1 , wherein said feed stream comprises more than about 10 ppmv oxygen.
7. The process of claim 1 , wherein the feed stream comprises C2 and C3 hydrocarbons.
8. The process of claim 1 , wherein the feed stream comprises more than about 200 ppmv nitrogen or more than about 400 ppmv carbon monoxide.
9. The process of claim 1 , wherein said feed stream is passed through said adsorbent bed at a pressure greater than about 15 bar (g) and a temperature less than about 50° C.
10. The process of claim 1 , wherein a hydrogen product stream is produced having a purity of over 99 mol % hydrogen and less than about 5 ppmv oxygen, preferably less than about 1 ppmv oxygen.
11. The process of claim 1 , wherein said copper material comprises greater than about 10 wt. % copper on an activated alumina support.
12. The process of claim 1 , wherein an upstream layer of adsorbent removes C2 and C3 impurities including ethylene and propylene.
13. The process of claim 12 , wherein said upstream layer of adsorbent comprises activated carbon.
14. The process of claim 1 , wherein a downstream layer of adsorbent from said copper material removes water and carbon dioxide generated in the copper material layer by reduction of copper oxides and by hydrogen oxidation and carbon monoxide oxidation reactions.
15. The process of claim 1 , wherein said oxygen is chemisorbed upon contacting said copper material in said higher pressure feed step and then reduced with production of water and carbon dioxide during a said lower pressure regeneration and purge step.
16. The process of claim 1 , wherein said purge step comprises sending a hydrogen-rich stream comprising 90 mol % or more hydrogen through said copper material bed.
17. The process of claim 1 , wherein said copper material layer comprises about 5 to about 20 volume % of said adsorbent bed.
18. The process of claim 12 , wherein said upstream layer comprises about 5 to about 30 volume % of said adsorbent bed.
19. The process of claim 14 , wherein said downstream layer comprises about 5 to about 30 volume % of said adsorbent bed.
20. The process of claim 1 , further comprising at least one of: sensing at least one parameter of the process and generating a signal or data from the sensing; generating and transmitting a signal; or generating and transmitting data.