초록 ▼

This invention comprises an adsorption process for the removal of at least N2O from a feed gas stream that also contains nitrogen and possibly CO2 and water. In the process the feed stream is passed over adsorbents to remove impurities such as CO2 and water, then over an additional adsorbent having

This invention comprises an adsorption process for the removal of at least N2O from a feed gas stream that also contains nitrogen and possibly CO2 and water. In the process the feed stream is passed over adsorbents to remove impurities such as CO2 and water, then over an additional adsorbent having a high N2O/N2 separation factor. In a preferred mode the invention is an air prepurification process for the removal of impurities from air prior to cryogenic separation of air. An apparatus for operating the process is also disclosed.

대표청구항 ▼

What is claimed is: 1. An adsorption purification process for the removal of N2O from a gas containing less than 100 ppm of N2O, nitrogen and other components, said process comprising passing said gas over a bed of one or more adsorbents and producing a purified gas, wherein said one or more adsorb

What is claimed is: 1. An adsorption purification process for the removal of N2O from a gas containing less than 100 ppm of N2O, nitrogen and other components, said process comprising passing said gas over a bed of one or more adsorbents and producing a purified gas, wherein said one or more adsorbents is selected from the group consisting of clinoptilolite, chabazite and Li-exchanged zeolite. 2. The process of claim 1, wherein said gas is air. 3. The process of claim 1, wherein said other components include water and CO2. 4. The process of claim 3, wherein said water and said CO2 are adsorbed on an additional adsorbent prior to said gas passing over said clinoptilolite, chabazite or said Li-exchanged zeolite. 5. The process of claim 1, wherein said process is either pressure swing adsorption or temperature swing adsorption. 6. The process of claim 1, wherein said process is a combination of temperature swing adsorption and pressure swing adsorption. 7. The process of claim 4, wherein at least 90% of the N2O in said gas is adsorbed. 8. The process of claim 1, wherein said adsorbent is clinoptilolite, and wherein between 30% and 80% of its exchangeable ions are sodium cations. 9. The process of claim 1, wherein said adsorbent has been washed with an acid or alkali solution prior to being placed in said bed. 10. The process of claim 1, wherein said Li-exchanged zeolite is LiX. 11. The process of claim 1, wherein said purified gas contains less than 100 ppb of N2O. 12. The process of claim 1, wherein said purified gas contains less than 50 ppb of N2O. 13. The process of claim 1, wherein said purified gas contains less than 10 ppb of N2O. 14. The process of claim 6, wherein in said pressure swing adsorption process, adsorption takes place at a pressure between 1.0 to 25 bar, and desorption takes place at a pressure between 0.2 to 10.0 bar. 15. The process of claim 6, wherein in said temperature swing adsorption process, adsorption takes place at a temperature between-70 degrees Celsius and 80 degrees Celsius, and desorption takes place at a greater temperature than said adsorption. 16. A process for the separation of N2O from a gas stream containing at least N2O and nitrogen, wherein the concentration of N2O is less than 100 ppm, said process comprising passing said gas stream over a bed of adsorbent having a ΔN2O working capacity of greater than or equal to 3.56×10-4 at IBL. 17. The process of claim 16, wherein said gas stream is air. 18. The process of claim 16, wherein said adsorbent is selected from the group consisting of clinoptilolite, chabazite, Li-exchanged zeolite and combinations thereof. 19. The process of claim 16, wherein the ΔN2O/ΔN2 selectivity is greater than or equal to 2.23×10-4 at IBL. 20. An adsorption apparatus for the removal of N2O from a gas containing N2O, nitrogen and other components, said apparatus comprising one or more beds of at least a first adsorbent, wherein said first adsorbent is an N2O selective adsorbent selected from the group consisting of clinoptilolite, chabazite and Li-exchanged zeolite or combinations thereof, wherein said apparatus comprises a layer of alumina and a mixed layer of said N2O selective adsorbent and an adsorbent selective for CO2 downstream of said layer of alumina. 21. An adsorption apparatus for the removal of N2O from a gas containing N2O, nitrogen and other components, said apparatus comprising one or more beds of at least a first adsorbent, wherein said first adsorbent is an N2O selective adsorbent selected from the group consisting of clinoptilolite, chabazite and Li-exchanged zeolite or combinations thereof, wherein said apparatus comprises a layer of alumina and, downstream therefrom, a layer of a composite material comprising said N2O selective adsorbent and an adsorbent selective for CO2 bound into a single particulate material.