Claims
- 1. A method for converting nitrogen oxides present in exhaust gases to harmless substances, which comprises:
- contacting an exhaust containing nitrogen oxides in the presence of ammonia as a reducing agent at a temperature of 200.degree. to 500.degree. C, and a space velocity of 2,000 to 10,000 hr.sup.1 with a catalyst consisting essentially of the oxides of V and Nb.
- 2. The method of claim 1, wheren the ratio of the atom number of Nb to the atom number of V is in the range of from 0.1 to 5.0.
- 3. A method for converting nitrogen oxides present in exhaust gases to harmless substances, which comprises:
- contacting an exhaust gas containing nitrogen oxides in the presence of ammonia as a reducing agent at temperature of 200.degree. to 500.degree. C and a space velocity of 2,000 to 100,000 hr.sup.-1 with a catalyst consisting essentially of the oxides of V, Nb and at least one element selected from the group consisting of Cu, Ti, Fe, Cr, W, Mo and Ni.
- 4. The method of claim 3, wherein the ratio of the total atom number of Nb and said element to the atom of V is in the range of from 0.1 to 5.0.
- 5. A method for converting nitrogen oxides present in exhaust gases to harmless substances, which comprises:
- contacting an exhaust gas containing nitrogen oxides in the presence of ammonia as a reducing agent at a temperature of 200.degree. to 500.degree. C and a space velocity of 2,000 to 100,000 hr.sup.-1 with a catalyst consisting essentially of the oxides of V, Nb and Ti.
- 6. The method of claim 3, wherein the ratio of the atom number of said element to the atom number of Nb is in the range of from 0.25 to 99.
- 7. The method of claim 5, wherein the atomic ratio of Nb to V is from 0.01 to 0.14 and the atomic ratio of Ti to V is from 0.4 to 0.8.
- 8. The method of claim 1, wherein said catalyst is supported on a carrier.
- 9. The method of claim 3, wherein said catalyst is supported on a carrier.
- 10. The method of claim 5, wherein said catalyst is supported on a carrier.
- 11. The method of claim 1, wherein said carrier is formed in a shape of beads, columns, Rashing rings, plates or of a honeycomb structure.
- 12. The method of claim 3, wherein said carrier is formed in a shape of beads, columns, Rashing rings, plates or of a honeycomb structure.
- 13. The method of claim 5, wherein said carrier is formed in a shape of beads, columns, Rashing rings, plates or of a honeycomb structure.
- 14. The method of claim 11, wherein said catalyst components are supported in an amount of 0.1 to 20% by weight based on said carrier.
- 15. The method of claim 12, wherein said catalyst components are supported in an amount of 0.1 to 20% by weight based on said carrier.
- 16. The method of claim 13, wherein said catalyst components are supported in an amount of 0.1 to 20% by weight based on said carrier.
- 17. The method of claim 14, wherein the catalyst components are supported in an amount of 1 to 10% by weight based on the carrier.
- 18. The method of claim 15, wherein the catalyst components are supported in an amount of 1 to 10% by weight based on the carrier.
- 19. The method of claim 16, wherein the catalyst components are supported in an amount of 1 to 10% by weight based on the carrier.
Priority Claims (1)
Number |
Date |
Country |
Kind |
50/108179 |
Sep 1975 |
JP |
|
Parent Case Info
This is a division, of application Ser. No. 710,330, filed July 30, 1976, now abandoned.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
3900428 |
Mai et al. |
Aug 1975 |
|
4010238 |
Shiraishi et al. |
Mar 1977 |
|
Non-Patent Literature Citations (1)
Entry |
"Chemical Abstracts" vol. 80, Mar. 1974, p. 41321a. |
Divisions (1)
|
Number |
Date |
Country |
Parent |
710330 |
Jul 1976 |
|