Claims
- 1. A method of purifying gaseous carbon dioxide comprising passing a stream of carbon dioxide through a silver-exchanged faujasite and a molecular sieve selected from the group consisting of an MFI-type molecular sieve with a Si:Al ratio greater than about 10, ZSM-12 and ZSM-23 where said faujasite and said sieve are in a proportion from about 1:3 to about 3:1, and recovering purified carbon dioxide having no more than 15 ppb COS and 10 ppt organic materials.
- 2. The method of claim 1 wherein the Si:Al ratio of said MFI-type molecular sieve is greater than about 20.
- 3. The method of claim 1 wherein said MFI-type molecular sieve is selected from the group consisting of ZSM-5 and silicalite.
- 4. The method of claim 1 wherein the silver-exchanged faujasite is silver-exchanged zeolite X.
- 5. The method of claim 1 further characterized in that said carbon dioxide is additionally passed through one or more of zeolites 3A, 4A, and 5A.
- 6. The method of claim 5 further comprising the purified carbon dioxide additionally depleted in water.
- 7. The method of claim 1 further characterized in that said carbon dioxide is additionally passed through a reduced metal on a matrix material.
- 8. The method of claim 7 further comprising the purified carbon dioxide additionally depleted in oxygen.
- 9. The method of claim 7 wherein the purified carbon dioxide has less than 1 ppm oxygen.
- 10. The method of claim 7 wherein the reduced metal is nickel or copper and the matrix material is a refractory inorganic oxide.
- 11. The method of claim 1 wherein from about 5 up to about 90 percent of the available sites on faujasite are exchanged with silver.
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of our copending application, application Ser. No. 08/947,721 filed Oct. 9, 1997, now U.S. Pat. No. 5,858,068, all of which is hereby incorporated by reference.
US Referenced Citations (20)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0586830 |
Mar 1994 |
EPX |
1565498 |
May 1990 |
SUX |
Continuation in Parts (1)
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Number |
Date |
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Parent |
947721 |
Oct 1997 |
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