Claims
- 1. A method for stabilizing a crystalline alumino-silicate zeolite catalyst against steam deactivation wherein said zeolite is characterized by a silica/alumina ratio of at least about 12 and a constraint index within the approximate range of 1 to 12 and when said zeolite is an organozeolite further characterized by having at least about 50% of its active cationic sites occupied by organic cations comprising intimately admixing said zeolite and a sufficient amount of a suitable charring agent and thereafter subjecting said zeolite catalyst to calcination at an elevated temperature below about 1100.degree. F. in a closed system having a limited amount of oxygen thereby converting a portion of said organic cations and/or charring agent to carbonaceous material of which at least about 1.5-15 wt. % is deposited and retained within the pores of said zeolite catalyst after said calcination.
- 2. The process of claim 1 wherein the sorption capacity of said catalyst is decreased by about 10 to 50% after conversion of organic cations and/or charring agent to carbonaceous material.
- 3. The process of claim 1 wherein the calcination temperature is from about 800.degree. to about 1050.degree. F.
- 4. The process of claim 1 wherein prior to admixing with a charring agent the zeolite is first calcined at a temperature of from about 700.degree.-1000.degree. F., in an inert atmosphere, ammonium ion exchanged, and thereafter mixed with said charring agent and calcined at a temperature of from about 800.degree.-1050.degree. F. for from about 1 to 20 hours.
- 5. The process of claim 1 wherein about 1.5-6.5 wt. % of carbonaceous material is deposited within the pores of the zeolite catalyst.
- 6. The process of claim 1 wherein the catalyst is selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-35 and ZSM-38.
- 7. The process of claim 6 wherein the catalyst is ZSM-5.
- 8. The process of claim 6 wherein the catalyst is a low sodium zeolite.
- 9. The process of claim 8 wherein the catalyst is a low sodium tetrapropylammonium ZSM-5 zeolite.
- 10. The process of claim 1 wherein the ZSM-5 type catalyst contains at least one metal cation selected from the group consisting of metals selected from Groups IB, IIB and VIII of the Periodic Table.
- 11. The process of claim 1 wherein the charring agents are selected from the group consisting of unsaturated hydrocarbons, dicyclic aromatics, picoline N-oxide and tripropyl N-oxide.
- 12. The process of claim 11 wherein the unsaturated hydrocarbons are selected from olefins, diolefins and the dicyclic aromatics are selected from cycle oils derived from catalytic cracking units.
- 13. The process of claim 1 wherein said zeolite catalyst is an organozeolite which is subjected to calcination without prior admixing with a charring agent.
- 14. The process of claim 13 wherein the organozeolite is air calcined.
- 15. The process of claim 14 wherein the catalyst is selected from an organo-ZSM-35 and organo-ZSM-38.
- 16. The process of claim 7 wherein the organic cations are selected from pyrrolidine, 1,4-butanediamine and choline chloride.
Parent Case Info
This is a continuation of copending application Ser. No. 801,881, filed May 31, 1977 and now abandoned.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
3525775 |
Bolton et al. |
Aug 1970 |
|
3676330 |
Plank et al. |
Jul 1972 |
|
3758403 |
Rosinski et al. |
Sep 1973 |
|
Continuations (1)
|
Number |
Date |
Country |
Parent |
801881 |
May 1977 |
|