Process for separation of hydrogen and oxygen
Embodiments of the invention are directed to methods, processes, and systems for safely and reliably purifying hydrogen from a gas mixture containing hydrogen and oxygen.
1. A process for separating hydrogen and oxygen from a gas mixture produced from photocatalytic splitting of water comprising:
(a) separating hydrogen and oxygen at about atmospheric pressure from a feed source by
(i) passing the feed source through a vacuum swing adsorption separation unit containing an adsorption medium comprising a carbon molecular sieve that selectively adsorbs hydrogen from the feed source producing an enriched oxygen product gas and an adsorption medium enriched in hydrogen; and
(ii) desorbing the adsorbed hydrogen by exposing the hydrogen enriched adsorption medium to a vacuum forming an hydrogen enriched purge gas and a regenerated adsorption medium, wherein the desorption process is performed at 15 to 60° C. and a pressure of about 0.1 mbar to 0.5 bar; and
(b) collecting, storing, or utilizing the product gas and purge gas.
2. The process of claim 1 , wherein the adsorption process is performed at 15 to 60° C.
3. The process of claim 1 , wherein two or more blowers are employed upstream and downstream of the vacuum swing adsorption unit.
4. The process of claim 1 , wherein the adsorption medium further comprises a metal oxide.
5. The process of claim 1 , wherein the adsorption process is performed at a pressure of 0.8 bar.
6. The process of claim 1 , wherein the adsorption medium further comprises a silica-magnesia.
7. The process of claim 1 , wherein the desorption process is performed at a pressure of about 0.1 mbar.
8. The process of claim 3 , wherein the desorption process is performed at a pressure of about 0.1 mbar.
9. The process of claim 1 , further comprising filtering and dehydrating the feed source prior to separating hydrogen and oxygen.
10. The process of claim 1 , wherein the adsorption medium comprises a 5 angstrom zeolite.
11. The process of claim 1 , wherein the adsorption medium further comprises at least one member selected from the group consisting of metal oxide, a clay, a silica, an alumina, a silica-alumina, a silica-magnesia, a silica-zirconia, a silica-thoria, a silica-berylia, a silica-titania, a silica-alumina-thoria, a silica-alumina-zirconia and aluminophosphates.
12. The process of claim 1 , wherein the feed source comprises about 70 mol % hydrogen.
13. The process of claim 1 , wherein the enriched hydrogen stream comprises at least 95 mol % hydrogen.
14. The process of claim 1 , wherein the process is performed under conditions and using equipment to minimize spark generation.
15. The process of claim 1 , wherein the adsorption medium further comprises silica-alumina-thoria.
16. The process of claim 1 , wherein the adsorption medium further comprises silica-thoria.
17. The process of claim 1 , wherein the adsorption medium further comprises a silica-berylia.