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US4571329A
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Ammonia reduction-denitration process and apparatus therefor
Assignee: Mitsubishi Power Ltd
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Filing: 1984-08-13
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Granted: 1986-02-18
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Expires: 2004-08-13
Abstract
Abstract An ammonia reduction-denitration process for exhaust gases containing NO x consisting mainly of NO 2 , and an apparatus therefor are provided, which process comprises treating the exhaust gases with ammonia using a catalyst which is active to both a reaction of (NO 2 +NH 3 →N 2 +N 2 O+H 2 O) and a reaction of (N 2 O+NH 3 →N 2 +H 2 O) at an area velocity of 3 m/h or less and in a concentration ratio of NH 3 /NO 2 of 1.3 or more. According to this process, it is possible to reduce NO 2 contained in the exhaust gases with ammonia at one stage without by-producing N 2 O.
Inventors
- 👤 Yasuyoshi Kato
- 👤 Kunihiko Konishi
- 👤 Masao Ohta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:45
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/8628; Y; Y02; Y02C; Y02C20/00; Y02C20/10
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
155 words
A process for the reduction of nitrogen oxides including nitrous oxide (N 2 O) in an exhaust gas with ammonia (NH 3 ) wherein N 2 O is present in the exhaust gas or is created in said process by a reaction of ammonia reducing nitrogen dioxide (NO 2 ), said process comprising: contacting the exhaust gas with ammonia in the presence of a catalyst consisting of zeolite ion substituted with hydrogen and iron, said catalyst being able to: (a) catalyze the formation reaction of nitrogen (N 2 ), N 2 O and water from NO 2 and NH 3 ; as well as (b) catalyze the formation reaction of N 2 and water from NH 3 and said N 2 O created by the reaction in (a); wherein NO 2 conprises at least 50% by weight of said nitrogen oxides; and wherein the ratio of NH 3 to NO 2 is at least 1.3.
Claim 2
Dependent Claim
155 words
A process for the reduction of nitrogen oxides including nitrous oxide (N 2 O) in an exhaust gas with ammonia (NH 3 ) wherein N 2 O is present in the exhaust gas or is created in said process by a reaction of ammonia reducing nitrogen dioxide (NO 2 ), said process comprising: contacting the exhaust gas with ammonia in the presence of a catalyst consisting of zeolite ion substituted with hydrogen and iron, said catalyst being able to: (a) catalyze the formation reaction of nitrogen (N 2 ), N 2 O and water from NO 2 and NH 3 ; as well as (b) catalyze the formation reaction of N 2 and water from NH 3 and said N 2 O created by the reaction in (a); wherein NO 2 conprises at least 50% by weight of said nitrogen oxides; and wherein the ratio of NH 3 to NO 2 is at least 1.3.
Claim 3
Dependent Claim
19 words
The process according to claim 1 wherein the ratio of NH 3 to NO 2 is at least 1.6.
Claim 4
Dependent Claim
21 words
A process according to claim 1, wherein said process is carried out at an area velocity of at least 5 m/h.
Claim 5
Dependent Claim
21 words
A process according to claim 1, wherein said process is carried out at an area velocity of at least 3 m/h.
Claim 6
Dependent Claim
22 words
A process according to claim 1, wherein said zeolite is selected from the group consisting of mordenite, clinoptilolite, faujasite and zeolite Y.
Claim 7
Dependent Claim
22 words
A process according to claim 1, wherein the substitution percentage of hydrogen and iron is in the range of 77 to 95%.
Claim 8
Independent Claim
165 words
An apparatus for the reduction of nitrogen oxides including nitrous oxide (N 2 O) in an exhaust gas with ammonia (NH 3 ), wherein N 2 O is present in the exhaust gas or is created in said process by a reaction of ammonia reducing nitrogen dioxide (NO 2 ), which apparatus comprises: a reactor provided with a catalyst which is able to catalyze the formation reaction of nitrogen (N 2 ), N 2 O and water from NO 2 and NH 3 , filled therein upstream and also provided with a catalyst consisting of a zeolite ion substituted with hydrogen and iron, said ion substituted zeolite catalyzing both the formation reaction of N 2 , N 2 O and water from NO 2 and NH 3 and the formation reaction of N 2 and water from N 2 O and NH 3 , filled therein downstream, said process being carried out in a ratio of NH 3 to NO 2 of at least 1.3.
Claim 9
Independent Claim
165 words
An apparatus for the reduction of nitrogen oxides including nitrous oxide (N 2 O) in an exhaust gas with ammonia (NH 3 ), wherein N 2 O is present in the exhaust gas or is created in said process by a reaction of ammonia reducing nitrogen dioxide (NO 2 ), which apparatus comprises: a reactor provided with a catalyst which is able to catalyze the formation reaction of nitrogen (N 2 ), N 2 O and water from NO 2 and NH 3 , filled therein upstream and also provided with a catalyst consisting of a zeolite ion substituted with hydrogen and iron, said ion substituted zeolite catalyzing both the formation reaction of N 2 , N 2 O and water from NO 2 and NH 3 and the formation reaction of N 2 and water from N 2 O and NH 3 , filled therein downstream, said process being carried out in a ratio of NH 3 to NO 2 of at least 1.3.
Claim 10
Dependent Claim
21 words
An apparatus according to claim 7, wherein said process is carried out at an area velocity of 5 m/h or less.
Claim 11
Dependent Claim
65 words
An apparatus according to claim 7, wherein said catalyst catalyzing in the formation reaction of N 2 , N 2 O and H 2 O from NO 2 and NH 3 is at least one selected from the group consisting of the oxides of Ti, V, W and Mo, and said zeolite is selected from the group consisting of mordenite, clinoptilolite, faujasite and zeolite Y.
Claim 12
Dependent Claim
22 words
An apparatus according to claim 7, wherein the substitution percentage of hydrogen and iron is in the range of 77 to 95%.
References Cited (Backward Citations)
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