Process for removing nitrogen oxides from gas by ammonia
First Claim
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1. A process for removing nitrogen oxides from a gas containing nitrogen oxides, which comprises adding a reducing agent selected from the group consisting of ammonia, ammonium salts, amines and amides and hydrogen peroxide to the gas, the gas having a temperature of 400°
- -1200°
C., thereby decomposing the nitrogen oxides to a nitrogen gas and water.
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Abstract
A hot gas containing nitrogen oxides is admixed with ammonia and hydrogen peroxide to reduce the nitrogen oxides to nitrogen and water. Reduction reaction of the nitrogen oxides by ammonia is considerably promoted in a temperature range of 400° to 800° C. by the addition of hydrogen peroxide, and also ammonia present in excess of the nitrogen oxides is decomposed thereby, eliminating an unreacted ammonia effluent.
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Citations
28 Claims
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1. A process for removing nitrogen oxides from a gas containing nitrogen oxides, which comprises adding a reducing agent selected from the group consisting of ammonia, ammonium salts, amines and amides and hydrogen peroxide to the gas, the gas having a temperature of 400°
- -1200°
C., thereby decomposing the nitrogen oxides to a nitrogen gas and water. - View Dependent Claims (2, 3, 4, 5, 7, 8, 9, 12)
- -1200°
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6. A process for removing nitrogen oxides from a gas containing nitrogen oxides, which comprises adding ammonia and hydrogen peroxide to the gas at a gas temperature of 400°
- to 1,200°
C., thereby decomposing the nitrogen oxides to a nitrogen gas and water. - View Dependent Claims (10, 11, 13)
- to 1,200°
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14. A process for removing nitrogen oxides from a gas containing nitrogen oxides, which comprises adding ammonia to the gas at a molar ratio of ammonia to nitrogen oxides of 0.3-10:
- 1, and hydrogen peroxide to the gas at a molar ratio of hydrogen peroxide to ammonia of 0.03-3;
1 in a temperature region of 400°
to 800°
C., thereby reducing the nitrogen oxides to a nitrogen gas and water. - View Dependent Claims (15, 16, 17, 18, 19)
- 1, and hydrogen peroxide to the gas at a molar ratio of hydrogen peroxide to ammonia of 0.03-3;
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20. A process for removing nitrogen oxides from a boiler combustion flue gas containing nitrogen oxides, wherein the flue gas passes, successively, through a furnace, a secondary superheater, a high temperature reheater, and a primary superheater, and wherein ammonia is added to the gas in the secondary superheater, and hydrogen peroxide is added to the gas at a downstream of the high temperature reheater, both of the ammonia and the hydrogen peroxide being added to the gas at a gas temperature of 400°
- to 1200°
C., thereby reducing the nitrogen oxides to a nitrogen gas and water. - View Dependent Claims (21, 22, 25)
- to 1200°
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23. A process for removing nitrogen oxides from a gas containing nitrogen oxides, which comprises adding ammonia and hydrogen peroxide to the gas at a gas temperature of 400°
- to 1,200°
C., thereby decomposing the nitrogen oxides to a nitrogen gas and water, whereby said decomposing is carried out without using a catalyst. - View Dependent Claims (24)
- to 1,200°
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26. A process for removing nitrogen oxides from a gas containing nitrogen oxides, which comprises adding a reducing agent selected from the group consisting of ammonia, ammonium salts, amines and amides and hydrogen peroxide to the gas, the gas containing 0 to 20% oxygen, the gas having a temperature of 400°
- -1200°
C., thereby decomposing the nitrogen oxides to a nitrogen gas and water, said decomposing being carried out without using a catalyst.
- -1200°
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27. A process for removing nitrogen oxides from a gas containing nitrogen oxides, which comprises adding ammonia to the gas at a molar ratio of ammonia to nitrogen oxides of 0.3-10:
- 1, and hydrogen peroxide to the gas at a molar ratio of hydrogen peroxide to ammonia of 0.03-3;
1, in a temperature region of 400°
to 800°
C., said gas containing 0 to 20% oxygen, thereby reducing the nitrogen oxides to a nitrogen gas and water, the reducing of the nitrogen oxides to a nitrogen gas and water being carried out without using a catalyst.
- 1, and hydrogen peroxide to the gas at a molar ratio of hydrogen peroxide to ammonia of 0.03-3;
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28. A process for removing nitrogen oxides from a boiler combustion flue gas containing nitrogen oxides, wherein the flue gas passes, successively, through a furnace, a secondary superheater, a high temperature reheater, and a primary superheater, and wherein ammonia is added to the gas in the secondary superheater, and hydrogen peroxide is added to the gas at a downstream of the high temperature reheater, both of the ammonia and the hydrogen peroxide being added to the gas at a gas temperature of 400°
- to 1200°
C., the boiler combustion flue gas containing 0 to 20% oxygen, thereby reducing the nitrogen oxides to a nitrogen gas and water, the reducing of the nitrogen oxides to a nitrogen gas and water being carried out without using a catalyst.
- to 1200°
Specification