초록 ▼

Process for the separation and purification of oxygen and nitrogen is disclosed which utilizes solutions of oxygen carriers to selectively absorb oxygen from a gaseous stream, leaving nitrogen as a byproduct. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolv

Process for the separation and purification of oxygen and nitrogen is disclosed which utilizes solutions of oxygen carriers to selectively absorb oxygen from a gaseous stream, leaving nitrogen as a byproduct. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolved in a solvent solution, which absorbs oxygen from an oxygen-containing gaseous feed stream such as atmospheric air and desorbs oxygen to a gaseous product stream. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, while the product stream is maintained at a sufficiently low oxygen pressure to keep the carrier in its deoxygenated form during desorption. In an alternate mode of operation, the carrier solution is maintained at a sufficiently low temperature and high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, and at a sufficiently high temperature to keep the carrier in its deoxygenated form during desorption. Under such conditions, exceptionally high oxygen concentrations on the order of 95% to 99% are obtained, as well as a long carrier lifetime in excess of 3 months, making the process commercially feasible.

대표청구항 ▼

1. A process for the separation and purification of oxygen and nitrogen comprising: (a) bringing an atmospheric air feed stream into contact with a solution containing a solvent or solvent mixture, an axial base and an oxygen carrier, said solvent or solvent mixture being capable of dissolving th

1. A process for the separation and purification of oxygen and nitrogen comprising: (a) bringing an atmospheric air feed stream into contact with a solution containing a solvent or solvent mixture, an axial base and an oxygen carrier, said solvent or solvent mixture being capable of dissolving the axial base and the oxygen carrier when they are present together, said axial base being capable of providing a coordinating atom to the oxygen carrier, and said oxygen carrier being a metal-containing complex having any of the structures ##STR## wherein M is a metal selected from cobalt, iron, copper, nickel, manganese, ruthenium or rhodium; X is --O--, --S--, ##STR## R is hydrogen, alkyl, aryl, halogen, alkoxy or a nitrogen-containing moiety; and Y is halide, nitrate, thiocyanate or cyanide; said solution absorbing oxygen from said atmospheric air feed stream; (b) collecting nitrogen from the atmospheric air feed stream after the oxygen has been absorbed; (c) desorbing oxygen from said solution to a gaseous product stream; and (d) collecting oxygen from the product stream after the oxygen has been desorbed. 2. A process for the separation and purification of oxygen comprising: (a) bringing a gaseous, oxygen-containing feed stream into contact with a solution containing a solvent or solvent mixture, an axial base and an oxygen carrier, said solvent or solvent mixture being capable of dissolving the axial base and the oxygen carrier when they are present together, said axial base being capable of providing a coordinating atom to the oxygen carrier, and said oxygen carrier being a metal-containing complex having any of the structures ##STR## wherein M is a metal selected from cobalt, iron, copper, nickel, manganese, ruthenium or rhodium; X is --O--, --S--, ##STR## R is hydrogen, alkyl, aryl, halogen, alkoxy or a nitrogen-containing moiety; and Y is halide, nitrate, thiocyanate or cyanide; said solution absorbing oxygen from said gaseous oxygen-containing feed stream; (b) desorbing oxygen from said solution to a gaseous product stream; and (c) collecting oxygen from the product stream after the oxygen has been desorbed. 3. The process of claims 1 or 2 wherein said desorption of oxygen is accomplished by bringing said solution into contact with a gaseous product stream with an oxygen partial pressure substantially less than that of said feed stream. 4. The process of claims 1 or 2 wherein said desorption of oxygen is accomplished by heating said solution and bringing it into contact with said gaseous product stream. 5. The process of claims 4 wherein the temperature of the feed stream is between about -50° C. and +95° C. and the temperature of the product stream is at least about 5° C. higher than the temperature of the feed stream. 6. The process of claim 1 or 2 wherein the metal is cobalt. 7. The process of claims 3 wherein the oxygen partial pressure of the product stream is at least about 10 mmHg less than the oxygen partial pressure of the feed stream. 8. The process of claim 7 wherein the oxygen partial pressure of the feed stream is substantially atmospheric or less than atmospheric. 9. The process of claim 7 wherein the oxygen partial pressure of the feed stream is at least about 10 mmHg higher than atmospheric and the oxygen partial pressure of the product stream is substantially atmospheric. 10. A process for the separation and purification of oxygen and nitrogen comprising: (a) bringing an atmospheric air feed stream into contact with a solution containing a solvent or solvent mixture and a pentacoordinate oxygen carrier, said solvent or solvent mixture being capable of dissolving said pentacoordinate oxygen carrier, and said pentacoordinate oxygen carrier being a metal-containing complex having any of the structures ##STR## wherein M is a metal selected from cobalt, iron, copper, nickel, manganese, ruthenium or rhodium; X is --O--, --S--, ##STR## and R is hydrogen, alkyl, aryl, halogen, alkoxy or a nitrogen-containing moiety; said solution absorbing oxygen from said atmospheric air feed stream; (b) collecting nitrogen from the atmospheric air feed stream after the oxygen has been absorbed; (c) desorbing oxygen from said solution to a gaseous product stream; and (d) collecting oxygen from the product stream after the oxygen has been desorbed. 11. The process of claims 1, 2, or 10 wherein the rates of absorption of oxygen into or desorption of oxygen from said solution are increased either by stirring or otherwise agitating said solution or by increasing the interfacial area between said feed stream and said solution, said interfacial area being increased by any of the following methods: (a) bubbling said feed stream through said solution; (b) spraying said solution through said feed stream; (c) forming a foam of said solution with said feed stream; (d) incorporating said solution into microporous beads; or (e) contacting said solution with said feed stream in a sieve-tray column or packed column. 12. The process of claims 1, 2 or 10 conducted at a temperature of between about -50° C. and +100° C. 13. The process of claims 1, 2 or 10 wherein the solvent is selected from lactones, lactams, sulfoxides, nitriles, amides, amines, esters, ethers, other nitrogen-containing liquids, water and mixtures thereof, the axial base is selected from secondary or tertiary nitrogen-atom-containing Lewis bases, imidazoles, ketones, amides, amines, sulfoxides and pyridines, and the oxygen carrier is selected from metal-containing bis(acetylacetone)ethylenediimines, N,N'-bis(salicylidene)ethylenediamines, bis(2-amino-1-benzaldehyde)ethylenediimines, dry-cave compounds, and N,N'-substituted-ethylenediamines. 14. The process of claim 13 wherein the solvent is selected from at least one of gamma-butyrolactone, dimethylsulfoxide, propylene carbonate, diethylsulfoxide, N-methylpyrrolidone, dimethylacetamide, dimethylformamide, formamide, gamma-valerolactone, delta-valerolactone, epsilon-caprolactone, tributylphosphate, diglyme and benzonitrile, and the axial base is selected from at least one of 1-methylimidazole, 2-methylimidazole, 1,2,-dimethylimidazole, dimethylsulfoxide, N,N'-diethylethylenediamine, 4-dimethylaminopyridine, 4-aminopyridine, 4,4-bipyridine, 4-methoxypyridine, 4-methylaminopyridine, 3,4-lutidine, 3,5-lutidine, pyridine, 4-methylpyridine, 4-cyanopyridine, pyrazine, 4-pyrrolidinopyridine and piperidine. 15. The process of claim 14 wherein the oxygen carrier is N,N'-bis(3-methoxysalicylidene)ethylenediaminecobalt(II). 16. The process of claim 14 wherein the oxygen carrier is N,N'-bis(3-methoxysalicylidene)tetramethylethylenediaminecobalt(II). 17. The process of claim 14 wherein the oxygen carrier is ##STR## wherein R 1 is a branched or straight-chain hydrocarbon or hetero-atom-containing bridge; R 2 is hydrogen or methyl; R 3 is methyl or benzyl; and R 4 is alkyl containing 2 to 3 carbon atoms. 18. The process of claims 1 or 10 wherein desorption is performed in two stages, the first of which results in desorption of a small percentage of the absorbed oxygen and a large percentage of the absorbed nitrogen, and the second stage of which results in desorption of a large percentage of the absorbed oxygen and a small percentage of the absorbed nitrogen. 19. A process for the separation and purification of oxygen comprising: (a) bringing a gaseous, oxygen-containing feed stream into contact with a solution containing a solvent or solvent mixture and a pentacoordinate oxygen carrier, said solvent or solvent mixture being capable of dissolving said pentacoordinate oxygen carrier, and said pentacoordinate oxygen carrier being a metal-containing complex having any of the structures ##STR## wherein M is a metal selected from cobalt, iron, copper, nickel, manganese, ruthenium or rhodium; X is --O--, --S--, ##STR## and R is hydrogen, alkyl, aryl, halogen, alkoxy or a nitrogen-containing moiety; said solution absorbing oxygen from said atmospheric air feed stream; (b) desorbing oxygen from said solution to a gaseous product stream; and (c) collecting oxygen from the product stream after the oxygen has been desorbed. 20. The process of claims 10 or 19 wherein said desorption of oxygen is accomplished by bringing said solution into contact with a gaseous product stream with an oxygen partial pressure substantially less than that of said feed stream. 21. The process of claims 10 or 19 wherein said desorption of oxygen is accomplished by heating said solution and bringing it into contact with said gaseous product stream. 22. The process of claims 10 or 19 wherein the metal is cobalt and the solvent is selected from lactones, lactams, sulfoxides, nitriles, amides, amines, nitrogen-containing liquids, esters, ethers, water and mixtures thereof. 23. The process of claim 22 wherein the oxygen carrier is N,N'-bis(salicylideneimino)di-n-propylaminecobalt(II). 24. The process of claims 10 or 19 wherein the oxygen partial pressure of the product stream is at least about 10 mm Hg less than the oxygen partial pressure of the feed stream. 25. The process of claims 10 or 19 wherein the oxygen partial pressure of the feed stream is substantially atmospheric or less than atmospheric. 26. The process of claims 10 or 19 wherein the oxygen partial pressure of the feed stream is at least about 10 mm Hg higher than atmospheric and the oxygen partial pressure of the product stream is substantially atmospheric. 27. The process of claims 10 or 19 wherein the temperature of the feed stream is between about -50° C. and +95° C. and the temperature of the product stream is at least about 5° C. higher than the temperature of the feed stream. 28. A solution useful for the separation of oxygen and nitrogen from atmospheric air comprising a solvent or solvent mixture, an axial base and an oxygen carrier, said solvent or solvent mixture being capable of dissolving the axial base and the oxygen carrier when they are present together, said axial base being capable of providing a coordinating atom to the oxygen carrier, and said oxygen carrier being a mutual-containing complex having any of the structures ##STR## wherein M is a metal selected from cobalt, iron, copper, nickel, manganese, ruthenium or rhodium; X is --O--, --S--, ##STR## R is hydrogen, alkyl, aryl, halogen, alkoxy or a nitrogen-containing moiety; and Y is halide, nitrate, thiocyanate or cyanide. 29. The solution of claim 28 wherein the solvent is selected from lactones, lactams, sulfoxides, nitriles, amides, amines, ester, ethers, other nitrogen-containing liquids, water and mixtures thereof, and the axial base is selected from Lewis bases containing secondary or tertiary nitrogen atoms, imidazoles, ketones, amides, amines, sulfoxides, pyrazines and pyridines. 30. The solution of claim 29 wherein the solvent is selected from lactones, lactams, sulfoxides, nitriles, amides, amines, esters, ethers, other nitrogen-containing liquids, water and mixtures thereof, the axial base is selected from at least one of 1-methylimidazole, 2-methylimidazole, 1,2,-dimethylimidazole, dimethylsulfoxide, N,N'-diethylethylenediamine, 4-dimethylaminopyridine, 4-aminopyridine, 4,4-bipyridine, 4-methoxypyridine, 4-methylaminopyridine, 3,4-lutidine, 3,5-lutidine, pyridine, 4-methylpyridine, 4-cyanopyridine, piperidine, 4-pyrrolidinopyridine and pyrazine, and the oxygen carrier is selected from N,N'-bis(3-methoxysalicylidene)ethylenediaminecobalt(II), N,N'-bis(3-methoxysalicylidene)tetramethylethylenediaminecobalt(II), and ##STR## wherein R 1 is a branched or straight-chain hydrocarbon or hetero-atom-containing bridge; R 2 is hydrogen or methyl; R 3 is methyl or benzyl; and R 4 is alkyl containing 2 to 3 carbon atoms. 31. The solution of claim 29 wherein the solvent is selected from gamma-butyrolactone and N-methylpyrrolidone or mixtures thereof, the axial base is 4-dimethylaminopyridine and the oxygen carrier is N,N'-bis(3-methoxysalicylidene)tetramethylethylenediaminecobalt(II). 32. The solution of claim 29 wherein the solvent is selected from gamma-butyrolactone and N-methylpyrrolidone or mixtures thereof, the axial base is selected from 4-aminopyridine and 4-cyanopyridine and the oxygen carrier is N,N'-bis(3-methoxysalicylidene)tetramethylethylenediaminecobalt(II). 33. The solution of claims 30, 31 or 32 wherein the solvent contains an additive of less than 20 wt%, the additive being selected from the group consisting of water, organic or inorganic acids or bases. 34. A solution useful for the separation of oxygen and nitrogen from atmospheric air comprising a solvent or solvent mixture and a pentacoordinate oxygen carrier, said solvent or solvent mixture being capable of dissolving said pentacoordinate oxygen carrier, and said pentacoordinate oxygen carrier being a metal-containing complex having any of the structures ##STR## wherein M is a metal selected from cobalt, iron, copper, nickel, manganese, ruthenium or rhodium; X is --O--, --S--, ##STR## and R is hydrogen, alkyl, aryl, halogen, alkoxy or a nitrogen-containing moiety. 35. The solution of claim 34 wherein the metal is cobalt and the solvent is selected from lactones, lactams, sulfoxides, nitriles, amides, amines, nitrogen-containing liquids, esters, ethers, water and mixtures thereof.