Startup procedure for reforming catalysts

Abstract

Process for reforming a hydrocarbon charge under reforming conditions in a reforming zone containing a sulfur-sensitive metal containing reforming catalyst wherein over-cracking of the charge stock and excessive temperature rise in the reforming zone is suppressed by pre-conditioning the catalyst, prior to contact with the charge, with a reformate of specified octane number and aromatics content.

What is claimed is: 
     
       1. In a process for reforming a hydrocarbon charge under reforming conditions in the presence of a .[.sulfur-sensitive metal-containing reforming catalyst.]. .Iadd.reforming catalyst selected from the group consisting of platinum, platinum and iridium or platinum, iridium and rhenium, .Iaddend.in a reforming zone, wherein said charge conducted to said reforming zone contacts said catalyst in an initial or .[.freshy.]. .Iadd.freshly .Iaddend.regenerated state giving rise to over-cracking of said charge with concomitant loss in activity thereof and excessive temperature rise in said zone, the improvement which comprises pre-treating said catalyst prior to contact with said charge by passing thereover a reformate characterized by an octane number (R+O) of between about 90 and about 100, .[.and.]. an aromatics content within the approximate range of 40 to 50 mole percent .Iadd.and sulfur content up to 10 ppm .Iaddend.for a period of time, generally at least about 0.5 hour and no more than about 3 hours at a temperature between about 600° F. and about 750° F., thereby substantially suppressing the adverse effects of said over-cracking and excessive temperature rise. 
     
     
       2. The process of claim 1 wherein said temperature is between 650° F. and about 700° F. 
     
     
       3. The process of claim 1 wherein said period of time is .[.generally.]. at least about 1 hour and no more than about 3 hours.  .[.4. The process of claim 1 wherein said reforming catalyst is a multimetallic catalyst comprising platinum in combination with rhenium and/or iridium deposited 
     
     
        on a refractory support..]. 5. The process of claim 1 wherein said catalyst comprises platinum and iridium deposited on a refractory support.  .[.6. The process of claim 1 wherein said catalyst comprises platinum and 
     
     
        rhenium deposited on a refractory support..]. 7. The process of claim 1, wherein said catalyst comprises a minor proportion of platinum deposited on a refractory support and a minor proportion of iridium .[.deposted.]. 
     
     
        .Iadd.deposited .Iaddend.on a separate support. 8. The process of claim 1 wherein said catalyst comprises a minor proportion of platinum and rhenium deposited on a refractory support and a mimor proportion .[.or.]. .Iadd.of .Iaddend.iridium deposited on a separate support.  .[.9. The process of 
     
     
        claim 4 wherein said support is alumina..]. 10. The process of claim 5 wherein said support is alumina.  .[.11. The process of claim 6 wherein 
     
     
        said support is alumina..]. 12. The process of claim 7 wherein said 
     
     
        support is alumina. 13. The process of claim 8 wherein said support is 
     
     
        alumina. 14. The process of claim 1 wherein said hydrocarbon charge is a 
     
     
        petroleum naphtha. 15. The process of claim 1 wherein said reformate constitutes at least in part a recycle stream of the reformate product produced in said reforming zone.  .[.16. The process of claim 1 wherein said reformate contains a small amount of sulfur, not exceeding about 10 
     
     
        ppm..]. 17. The process of .[.claim 16.]. .Iadd.claims 1, 2, 3, 10, 12, 13, or 15 .Iaddend.wherein said charge initially contains between about 2 and about 10 ppm of sulfur and said catalyst is exposed thereto for a period of time within the approximate range of 5 to 24 hours, after which the catalyst is contacted with the charge of lower sulfur content. .Iadd. 18. The process of claim 17 wherein said charge initially contains about 4 to about 8 ppm of sulfur. .Iaddend..Iadd. 19. The process of claim 18 wherein said charge of lower sulfur content contains 2 ppm or less of sulfur. .Iaddend..Iadd. 20. The process of claim 1 wherein said catalyst comprises platinum. .Iaddend..Iadd. 21. The process of claim 20 wherein said catalyst additionally comprises a halogen component. .Iaddend..Iadd. 22. The process of claim 21 wherein the platinum content of the catalyst is about 0.01 to about 3 percent, based on the weight of the catalyst, and the halogen content of the overall catalyst is about 0.1 to about 5 weight percent. .Iaddend..Iadd. 23. The process of claim 22 wherein said halogen is chlorine, bromine or fluorine. .Iaddend..Iadd. 24. The process of claim 23 wherein said halogen is chlorine. .Iaddend..Iadd. 25. The process of claims 10 or 12 wherein said catalyst additionally comprises a halogen component. .Iaddend..Iadd. 26. The process of claim 25 wherein the platinum content of said catalyst is about 0.01 to about 3 percent, based on the weight of the catalyst, the iridium content of said catalyst is about 0.01 to about 3 percent, based on the weight of the catalyst, and the halogen content of the overall catalyst is about 0.1 to about 5 weight percent. .Iaddend..Iadd. 27. The process of claim 26 wherein said halogen is chlorine, bromine or fluorine. .Iaddend..Iadd. 28. The process of claim 27 wherein said halogen is chlorine. .Iaddend..Iadd. 29. The process of claim 13 wherein said catalyst additionally comprises a halogen component. .Iaddend..Iadd. 30. The process of claim 29 wherein the platinum content of said catalyst is about 0.01 to about 3 percent, based on the weight of the catalyst, the iridium content of said catalyst is about 0.01 to about 3 percent, based on the weight of the catalyst, the rhenium content of said catalyst is about 0.01 to about 3 percent, based on the weight of the catalyst, and the halogen content of the overall catalyst is about 0.01 to about 5 weight percent. .Iaddend..Iadd. 31. The process of claim 30 wherein said halogen is chlorine, bromine or fluorine. .Iaddend..Iadd. 32. The process of claim 31 wherein said halogen is chlorine. .Iaddend.