NOVEL MICROPOROUS CRYSTALLINE MATERIAL COMPRISING A MOLECULAR SIEVE OR ZEOLITE HAVING AN 8-RING PORE OPENING STRUCTURE AND METHODS OF MAKING AND USING SAME

• US 20080241060A1
• Filed: 03/26/2008
• Published: 10/02/2008
• Est. Priority Date: 03/26/2007
• Status: Active Grant

• Current Assignee: Ecovyst Catalyst Technologies LLC
• Original Assignee: PQ Corporation (Ecovyst, Inc.)
• Inventors: Moden, Bjorn, Cormier, William E., Li, Hong-Xin
• Granted Patent: US 7,645,718 B2
• Time in Patent Office: Days
• US Class Current: 423/700
• CPC Class Codes: B01D 2251/2062 Ammonia
• CPC Class Codes: B01D 2255/20738 Iron
• CPC Class Codes: B01D 2255/20761 Copper
• CPC Class Codes: B01D 2255/50 Zeolites
• CPC Class Codes: B01D 53/9418 for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas
• CPC Class Codes: B01J 2229/18 to introduce other elements into or onto the molecular sieve itself
• CPC Class Codes: B01J 29/85 Silicoaluminophosphates [SAPO compounds]

Abstract

There is disclosed a hydrothermally stable microporous crystalline material comprising a molecular sieve or zeolite having an 8-ring pore opening structure, such as SAPO-34 or aluminosilicate zeolite, able to retain a specific percentage of its surface area and micropore volume after treatment with heat and moisture, such as at least 80% of its surface area and micropore volume after exposure to temperatures of up to 900° C. in the presence of up to 10 volume percent water vapor for a time ranging from 1 to 16 hours. Methods of using the disclosed crystalline material, such as in the SCR of NO_x in exhaust gas are also disclosed, as are methods of making such materials.

Claims

1. A hydrothermally stable microporous crystalline material comprising a silicoaluminophosphate (SAPO) molecular sieve or aluminosilicate zeolite having an 8-ring pore opening structure, wherein said crystalline material retains at least 80% of its surface area and micropore volume after exposure to temperatures of up to 900°

C. in the presence of up to 10 volume percent water vapor for a time ranging from 1 to 16 hours.

2. A microporous crystalline material of claim 1, wherein said crystalline material comprises iron and/or copper.

3. A microporous crystalline material of claim 2, wherein said iron and/or copper are introduced into said solid by liquid-phase or solid ion-exchange or incorporated by direct-synthesis.

4. A microporous crystalline material of claim 1, wherein said SAPO molecular sieve or aluminosilicate zeolite having an 8-ring pore opening structure comprises SAPO-34, high-silica chabazite, or has a structure defined by the Structure Commission of the International Zeolite Association as CHA.

5. A microporous crystalline material of claim 4, wherein said SAPO-34 contains SiO₂ in an amount ranging from 1-20%.

6. A microporous crystalline material of claim 4, wherein said SAPO-34 has a crystal size greater than 0.3 microns.

7. A microporous crystalline material of claim 4, wherein said high-silica chabazite has a SAR ranging from 15-60.

8. A microporous crystalline material of claim 1, having an initial surface area of at least 650 m²/g.

9. A microporous crystalline material of claim 1, having an initial micropore volume of at least 0.25 cc/g.

10. A microporous crystalline material comprising a SAPO molecular sieve or aluminosilicate zeolite having an 8-ring structure defined by the Structure Commission of the International Zeolite Association chosen from:

AEI, AFT, AFX, CHA, DDR, ERI, ITE, ITW, KFI, LEV, LTA, PAU, RHO, and UFI, wherein said crystalline material retains at least 80% of its surface area and micropore volume after exposure to temperatures of up to 900°

C. in the presence of up to 10 volume percent water vapor for a time ranging from 1 to 16 hours.

11. A microporous crystalline material of claim 10, wherein said crystalline material has an aluminosilicate having an SAR greater than 15.

12. A microporous crystalline material of claim 11, wherein said SAR ranges from 20-60.

13. A microporous crystalline material of claim 10, wherein said crystalline material further comprises iron and/or copper.

14. A microporous crystalline material of claim 13, wherein said iron and/or copper are introduced into said crystalline material by liquid-phase or solid ion-exchange or incorporated by direct-synthesis.

15. A microporous crystalline material of claim 10, wherein said crystalline material comprises a SAPO molecular sieve structure containing 1-20% of SiO₂.

16. A hydrothermally stable microporous crystalline material comprising a molecular sieve or zeolite having an 8-ring pore opening structure for SCR of NO_x with urea or ammonia, wherein said crystalline material comprises iron and/or copper and retains at least 80% of its surface area and micropore volume after exposure to temperatures of up to 900°

C. in the presence of up to 10 volume percent water vapor for up to 1 hour.

17. A microporous crystalline material of claim 16, wherein the iron and/or copper are introduced into said material by liquid-phase or solid ion-exchange or incorporated by direct-synthesis.

18. A microporous crystalline material of claim 16, wherein iron oxide comprises at least 0.20 weight percent of the total weight of said material.

19. A microporous crystalline material of claim 16, wherein copper oxide comprises at least 1.0 weight percent of the total weight of said material.

20. A microporous crystalline material of claim 16, wherein said crystalline material is a microporous aluminosilicate with an SAR of greater than 15.

21. A microporous crystalline material of claim 20, wherein said SAR ranges from 20-60.

22. A microporous crystalline material of claim 16, wherein said crystalline material comprises a SAPO structure containing 1-20% of SiO₂.

23. A method of SCR of NO_x in exhaust gas, said method comprising:

contacting, in the presence of ammonia or urea, exhaust gas with a hydrothermally stable microporous crystalline material comprising a molecular sieve or zeolite having an 8-ring pore opening structure, wherein said crystalline material retains at least 80% of its surface area and micropore volume after exposure to temperatures of up to 900°

C. in the presence of up to 10 volume percent water vapor for a time ranging from 1 to 16 hours.

24. A method of SCR of NO_x in exhaust gas, said method comprising:

contacting, in the presence of ammonia or urea, exhaust gas with a microporous crystalline material chosen from molecular sieves and zeolites having an 8-ring pore opening structure defined by the Structure Commission of the International Zeolite Association chosen from;

AEI, AFT, AFX, CHA, DDR, ERI, ITE, ITW, KFI, LEV, LTA, PAU, RHO, and UFI, wherein said crystalline material retains at least 80% of its surface area and micropore volume after exposure to temperatures of up to 900°

C. in the presence of up to 10 volume percent water vapor for a time ranging from 1 to 16 hours.

25. A method of SCR of NO_x in exhaust gas, said method comprising:

contacting, in the presence of ammonia or urea, exhaust gas with a hydrothermally stable microporous crystalline material having an 8-ring pore opening structure for SCR of NO_x with urea or ammonia, wherein said crystalline material comprises iron and/or copper and retains at least 80% of its surface area and micropore volume after exposure to temperatures of up to 900°

C. in the presence of up to 10 volume percent water vapor for a time ranging from 1 to 16 hours.

26. A method for making silicoaluminophosphate molecular sieve, said method comprising:

mixing sources of alumina, silica, and phosphate with a TEAOH solution and water to form a gel;

heating said gel in an autoclave at a temperature ranging from 150 to 180°

C. for a time ranging from 12-60 hours to form a product;

cooling and optionally washing said product in water;

calcining said product to form a molecular sieve or zeolite having an 8-ring pore opening structure, wherein said crystalline material contains 1-20% SiO₂ and retains at least 80% of its surface area and micropore volume after exposure to temperatures of up to 900°

C. in the presence of up to 10 volume percent water vapor for a time ranging from 1 to 16 hours.