Claims
- 1. The method of removing nitrogen oxides from a flue gas containing sulphur oxides in excess of 100 ppm, oxygen and water vapor, comprising employing in said flue gas at least one of the reductants hydrogen and carbon monoxide in an amount between 1 and 2 times the theoretical amount required to reduce said nitrogen oxides and to react with said oxygen, and contacting said flue gas and reductant with a catalyst at a temperature in the range of about 300.degree.-450.degree. C, said catalyst consisting essentially of about 5.0% by weight of copper; about 0.005 to 0.05% by weight of rhodium; about 3.0% by weight of one of the metals potassium, barium, magnesium, chromium, manganese and molybdenum; and alumina; said catalyst acting to promote the substantially complete reduction of said nitrogen oxides by and the substantially complete reaction of said oxygen with said reductant, with substantially no conversion of said sulphur oxides into another substance and with substantially no conversion of said nitrogen oxides into ammonia.
- 2. The method set forth in claim 1 wherein said exhaust gas is reacted with a first catalyst to decrease the concentration of oxygen in said exhaust gas and thereby decrease the amount of reductant required to be employed in the method of claim 1.
- 3. The method of removing nitrogen oxides from a flue gas containing sulphur oxides in excess of 100 ppm, oxygen and water vapor comprising employing methane in said flue gas as a reductant in an amount between 1 and 2 times the theoretical amount required to reduce said nitrogen oxides and to react with said oxygen, and contacting said flue gas and reductant with a catalyst at a temperature of at least 600.degree. C, said catalyst consisting essentially of about 5.0% by weight of copper; about 0.005 to 0.05% by weight of rhodium; about 3.0% by weight of one of the metals potassium, barium, magnesium, chromium, manganese and molybdenum; and alumina; said catalyst acting to promote the substantially complete reduction of said nitrogen oxides by and the substantially complete reaction of said oxygen with said reductant, with substantially no conversion of said sulphur oxides into another substance and with substantially no conversion of said nitrogen oxides into ammonia.
- 4. The method set forth in claim 3 wherein said exhaust gas is reacted with a first catalyst to decrease the concentration of oxygen in said exhaust gas and thereby decrease the amount of reductant required to be employed in the method of claim 3.
Priority Claims (1)
Number |
Date |
Country |
Kind |
48-59479 |
May 1973 |
JPX |
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Parent Case Info
This is a continuation of application Ser. No. 667,674, filed May 17, 1976, said application being a continuation of application Ser. No. 471,182, filed May 20, 1974, and both now abandoned.
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3429656 |
Taylor et al. |
Feb 1969 |
|
3816594 |
Kobylinski et al. |
Jun 1974 |
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3835069 |
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Continuations (1)
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Number |
Date |
Country |
Parent |
667674 |
Mar 1976 |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
471182 |
May 1974 |
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