Claims
- 1. A process for treating iron, nickel and vanadium contaminated catalyst which has been poisoned in a hydrocarbon conversion process by a feedstock containing those metal poisons to remove at least a portion of these metal contaminants and to produce a catalyst with improved catalytic activity which comprises
- contacting at least a portion of said metal contaminated catalyst with at least one sulfur containing compound to provide a catalyst containing sulfur containing metal compounds wherein the amount of sulfur present on the catalyst is about 40 to about 90% of the total amount of iron, nickel and vanadium initially present on the catalyst;
- contacting said catalyst containing sulfur containing metal compounds with an oxygen containing medium to promote subsequent metals removal by converting at least a portion of said catalyst metals to a dispersible form;
- contacting said oxygen treated catalyst with an aqueous reductive wash medium to remove at least a portion of said metal poisons and subjecting said reductively washed catalyst to an aqueous oxidative wash; and
- recovering a catalyst of reduced metal poison content and improved catalytic activity.
- 2. A process as in claim 1 wherein said oxygen containing medium comprises an oxygen containing gas.
- 3. A process as in claim 2 wherein said oxygen containing gas contacts said catalyst at a temperature within the range of from 550.degree. F. to 725.degree. F.
- 4. A process as in claim 2 wherein the oxygen containing gas contacts said catalyst within the temperature range of from about 600.degree. F. to about 700.degree. F.
- 5. A process as in claim 2 wherein the oxygen containing gas contacts said catalyst within the temperature range of from about 620.degree. F. to about 680.degree. F.
- 6. A process as in claim 2 which includes the presence of steam during said oxygen contact step.
- 7. A process as in claim 1 wherein the reductive, aqueous wash medium is a solution of SO.sub.2 in water.
- 8. A process as in claim 7 wherein the solution is a saturated SO.sub.2 solution.
- 9. A process as in claim 8 wherein said reductive wash includes a temperature of about 65.degree.-80.degree. C. and a contact time of about 0.5-10 minutes.
- 10. A process as in claim 9 where said contact time is about 1-5 minutes.
- 11. A process as in claim 1 wherein the oxidative wash medium is an aqueous solution of hydrogen peroxide.
- 12. A process as in claim 11 wherein said oxidative wash includes a temperature of about 70.degree.-85.degree. C. and a contact time of about 3-5 minutes.
- 13. A process as in claim 12 wherein said aqueous hydrogen peroxide comprises about 2 to 30 weight % hydrogen peroxide.
- 14. A process as in claim 1 which further comprises removing at least a portion of the metal poisons from the oxygen treated catalyst by contacting said oxygen treated catalyst with alternate reductive and oxidative washes, the last wash comprising an oxidative wash.
- 15. A process as in claim 1 wherein the contaminated catalyst comprises a zeolite molecular sieve.
- 16. A process as in claim 15 wherein said zeolitic molecular sieve comprises a decationized zeolitic molecular sieve having less than 90% of the aluminum atoms associated with cations, a crystalline structure capable of internally absorbing benzene and a SiO.sub.2 to Al.sub.2 O.sub.3 molar ratio greater than 3.
- 17. A process as in claim 1 wherein said sulfur containing compound is hydrogen sulfide or a sulfur containing compound capable of being converted to hydrogen sulfide.
- 18. A process as in claim 17 wherein said sulfur containing compound is an admixture with a reducing gas.
- 19. A process as in claim 18 wherein said reducing gas is hydrogen or carbon monoxide.
- 20. A process as in claim 1 wherein the amount of sulfur present in the catalyst is about 40 to 75% of the total amount of nickel, iron and vanadium.
- 21. In a catalytic cracking process for converting a metals contaminated hydrocarbon feedstock to more valuable, lower boiling hydrocarbon products in a cracking reaction zone wherein the cracking catalyst is poisoned and contaminated by metals including iron, nickel and vanadium present in the feedstock, the improvement which comprises
- (i) withdrawing at least a portion of said metal contaminated catalyst from the cracking reaction zone;
- (ii) contacting at least a portion of said metal contaminated catalyst with at least one sulfur containing compound to provide a catalyst containing sulfur containing metals compounds wherein the amount of sulfur present on the resultant catalyst is about 40 to about 90% of the total amount of iron, nickel and vanadium initially present on the catalyst;
- (iii) contacting said catalyst containing sulfur containing metal compound with an oxygen-containing medium to promote subsequent metals removal by converting at least a portion of said catalyst metals to a dispersible form;
- (iv) contacting said oxygen treated catalyst with an aqueous reductive wash medium and subjecting said reductively washed catalyst to an aqueous oxidative wash to remove at least a portion of the metal poisons from the oxygen treated catalyst;
- (v) recovering a catalyst of reduced metal poison content and improved catalytic activity; and
- (vi) returning at least a portion of said recovered catalyst to the catalytic cracking process.
- 22. A process as in claim 21 wherein said oxygen containing medium comprises an oxygen containing gas.
- 23. A process as in claim 22 wherein said oxygen containing gas contacts said catalyst at a temperature within the range of from about 550.degree. F. to 725.degree. F.
- 24. A process as in claim 22 wherein the oxygen-containing gas contacts said catalyst within the temperature range of from about 600.degree. F. to about 700.degree. F.
- 25. A process as in claim 22 wherein the oxygen-containing gas contacts said catalyst within the temperature range of from about 620.degree. F. to about 680.degree. F.
- 26. A process as in claim 22 which includes the presence of steam during said oxygen contact step.
- 27. A process as in claim 21 wherein the reductive aqueous wash medium is a solution of SO.sub.2 in water.
- 28. A process as in claim 27 wherein the solution is a saturated SO.sub.2 solution.
- 29. A process as in claim 28 wherein said reductive wash includes a temperature of about 65.degree.-80.degree. C. and a contact time of about 0.5-10 minutes.
- 30. A process as in claim 29 where said reductive wash contact time is about 1-5 minutes.
- 31. A process as in claim 29 wherein the oxidative wash medium is an aqueous solution of hydrogen peroxide.
- 32. A process as in claim 31 wherein said reductive wash includes a temperature of about 60.degree.-85.degree. C. and a contact time of about 1-5 minutes.
- 33. A process as in claim 32 wherein said aqueous hydrogen peroxide comprises about 2 to 30 weight % hydrogen peroxide.
- 34. A process as in claim 21 which further comprises removing at least a portion of the metal poisons from the oxygen treated catalyst by contacting said oxygen treated catalyst with alternate reductive and oxidative washes, the last wash comprising an oxidative wash.
- 35. A process as in claim 21 wherein the contaminated catalyst comprises a zeolitic molecular sieve.
- 36. A process as in claim 35 wherein said zeolitic molecular sieve comprises a decationized zeolitic molecular sieve having less than 90% of the aluminum atoms associated with cations, a crystalline structure capable of internally absorbing benzene and a SiO.sub.2 to Al.sub.2 O.sub.3 molar ratio greater than 3.
- 37. A process as in claim 21 wherein said sulfur containing compound is hydrogen sulfide or a sulfur containing compound capable of being converted to hydrogen sulfide.
- 38. A process as in claim 37 wherein said sulfur containing compound is an admixture with a reducing gas.
- 39. A process as in claim 38 wherein said reducing gas is hydrogen or carbon monoxide.
- 40. A process as in claim 21 wherein the amount of sulfur on the catalyst is about 40 to 75% of the total amount of iron, nickel and vanadium.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of co-pending applications, Ser. Nos. 695,602; 695,662; and 695,687; each of which was filed on June 14, 1976, now U.S. Pat. Nos. 4,243,550; 4,101,444; and 4,102,811 respectively.
US Referenced Citations (5)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
695602 |
Jun 1976 |
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