Claims
- 1. A method for reactivating a sulfur oxide-poisoned, noble metal-containing zeolite catalyst which comprises removing at least some of said sulfur oxides from said catalyst by contacting said catalyst with an aqueous solution containing a Bronsted acid compound having a dissociation constant ranging from about 1.times.10.sup.-14 to about 2.times.10.sup.-1 which has been added such that the resulting aqueous solution has a pH ranging from about 0.1 to about 2, wherein said contacting is carried out at about 25.degree. to 100.degree. C., and about 15 to 600 psig for about 0.5 to 10 hours, without redispersing said noble metal.
- 2. The method of claim 1 wherein said compound is an ammonium salt.
- 3. The method of claim 2 wherein said ammonium salt is selected from the group consisting of ammonium carbonate and ammonium nitrate.
- 4. The method of claim 1 wherein said compound is selected from the group consisting of nitric acid, carbonic acid and hydrogen peroxide.
- 5. The method of claim 1 wherein said compound is an organic acid.
- 6. The method of claim 5 wherein said organic acid is selected from the group consisting of acetic acid and formic acid.
- 7. The method of claim 1 wherein said compound is a hydrogen halide.
- 8. The method of claim 1 wherein said compound is hydrogen chloride.
- 9. The method of claim 1 wherein said compound is hydrogen fluoride.
- 10. The method of claim 1 wherein said aqueous solution contains hydrogen peroxide and hydrogen fluoride.
- 11. The method of claim 1 wherein said contacting is carried out at about 25.degree. to 80.degree. C. and about 15 to 400 psig for about 0.5 to 2 hours.
- 12. The method of claim 1 wherein said zeolite is selected from the group consisting of ZSM-3, ZSM-4, ZSM-18, ZSM-20, zeolite beta, zeolite X and zeolite Y.
- 13. The method of claim 1 wherein said zeolite is selected from the group consisting of ZSM-5, ZSM-11, ZSM-5/ZSM-11 intermediate, ZSM-12, ZSM-23, ZSM-35, ZSM-38 and ZSM-48.
- 14. The process of claim 1 wherein said catalyst is a composite of said zeolite material and a matrix.
- 15. The method of claim 14 wherein said matrix is alumina.
- 16. The method of claim 1 wherein said noble metal is selected from the group consisting of platinum, palladium, osmium, iridium and rhodium.
- 17. The method of claim 1 wherein said noble metal is platinum.
- 18. The method of claim 1 wherein said catalyst is thereafter dried and exposed to reducing conditions.
- 19. The method of claim 1 wherein said noble metal is in the reduced or sulfided form prior to said contacting with aqueous solution.
Parent Case Info
This is a continuation of copending application Ser. No. 33,564, filed on Apr. 3, 1987, now abandoned which is a continuing application of U.S. patent application Ser. No. 800,581, filed Nov. 21, 1985, now U.S. Pat. No. 4,678,764, the contents of which are incorporated herein by reference.
US Referenced Citations (11)
Continuations (2)
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Number |
Date |
Country |
Parent |
33564 |
Apr 1987 |
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Parent |
800581 |
Nov 1985 |
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