EP0686813A2
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EP
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Method and apparatus for sequentially staged combustion using a catalyst
Assignee: Siemens Energy Inc
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Filing: 1995-06-07
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Granted: —
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Expires: 2015-06-07
Abstract
Abstract A low NOx generating combustor in which a first lean mixture of fuel and air is pre-heated by transferring heat from hot gas (41) discharging from the combustor. The pre-heated first fuel/air mixture is then catalyzed in a catalytic reactor (86) and then combusted so as to produce a hot gas having a temperature in excess of the ignition temperature of the fuel. Second and third lean mixtures of fuel (32) and air are then sequentially introduced into the hot gas, thereby raising their temperatures above the ignition temperature and causing homogeneous combustion of the second and third fuel air mixtures. This homogeneous combustion is enhanced by the presence of the free radicals created during the catalyzation of the first fuel/air mixture. In addition, the catalytic reactor acts as a pilot that imparts stability to the combustion of the lean second and third fuel/air mixtures.
Inventors
- 👤 Jeffrey Charles Bowker
- 👤 Dennis Michael Bachovchin
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 06:39
CPC Classifications
F; F23; F23C; F23C9/00; F23C13/00; F23C6/00; F23C6/04; F23C6/045; F23C6/047; F23C7/00; F23C7/02; F23C7/06; F23R; F23R3/00; F23R3/28; F23R3/34; F23R3/343; F23R3/346; F23R3/40; Y; Y02; Y02E; Y02E20/00; Y02E20/34
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
145 words
A combustor (15) for burning a fuel in air, characterized by means (75) for mixing a first flow of fuel (30) into a first flow of air (18) in a mixing zone (59), thereby producing a first fuel/air mixture (83), a combustion catalyst (86), and means (60) for directing said first fuel/air mixture through said catalyst so as to produce a catalyzed fuel/air mixture, a first combustion zone (93) in which said catalyzed fuel/air mixture is combusted, thereby producing a combusted gas (38), a second combustion zone (94) disposed downstream of said first combustion zone, and means (61) for directing said combusted gas from said first combustion zone to said second combustion zone, and means (87) for mixing a second fuel/air mixture (84) into said hot gas in said second combustion zone and combusting said second fuel/air mixture, thereby producing a further combusted gas (39).
Claim 2
Dependent Claim
55 words
The combustor according to claim 1, further characterized by means for mixing a second flow of fuel (32) into a second flow of air (18) so as to produce said second fuel/air mixture (84), and wherein said second flow of fuel and air mixing means comprises an annular passage (76) encircling said combustion catalyst (86).
Claim 3
Dependent Claim
69 words
The combustor according to claim 1, further characterized by a third combustion zone (95) disposed downstream of said second combustion zone (94), and means (62) for directing said further combusted gas (39) from said second combustion zone (94) to said third combustion zone, and means (88) for mixing a third fuel/air mixture (85) into said further combusted gas in said third combustion zone and combusting said third fuel/air mixture.
Claim 4
Dependent Claim
32 words
The combustor according to claim 1, further characterized by means (33, 80, 100) for heating said first fuel/air mixture (83) prior to directing said first fuel/air mixture through said combustion catalyst (86).
Claim 5
Dependent Claim
35 words
The combustor according to claim 4, wherein said means for heating said first fuel/air mixture comprises means (33, 80, 100) for transferring heat from said further combusted gas (39) to said first fuel/air mixture (83).
Claim 6
Dependent Claim
34 words
The combustor according to claim 5, wherein said means for transferring heat comprises means (33, 80) for mixing at least a portion of said further combusted gas (39) into said first fuel/air mixture (83).
Claim 7
Dependent Claim
59 words
The combustor according to claim 4, wherein said means for heating said first fuel/air mixture (83) is further characterized by means (95) for combusting a third flow of fuel (32) in air (20) so as to produce a still further combusted gas (40), and means (33, 80) for mixing said still further combusted gas into said first fuel/air mixture.
Claim 8
Dependent Claim
49 words
The combustor according to claim 4, wherein said means for heating said first fuel/air mixture (83) comprises means (33, 80) for mixing at least a portion of said further combusted gas (39) into said first flow of air (18) prior to mixing said first flow of fuel (30) therein.
Claim 9
Independent Claim
115 words
A method of combusting a fuel in air, characterized by the steps of mixing a first flow of fuel into a first flow of air so as to form a first fuel/air mixture, flowing said first fuel/air mixture through a combustion catalyst, thereby producing a catalyzed fuel/air mixture, combusting said catalyzed fuel/air mixture, thereby producing a combusted gas, mixing a second flow of fuel into a second flow of air so as to form a second fuel/air mixture, and combusting said second fuel/air mixture by mixing said second fuel/air mixture into said combusted gas so as to raise the temperature of said second fuel/air mixture above its ignition temperature, thereby producing a further combusted gas.
Claim 10
Dependent Claim
61 words
The method according to claim 9, further characterized in that the step of combusting said catalyzed fuel/air mixture occurs in a first combustion zone of a combustor, said first combustion zone being disposed downstream from said catalyst, and the step of mixing and combusting said second fuel/air mixture occurs in a second combustion zone disposed downstream from said first combustion zone.
Claim 11
Dependent Claim
62 words
The method according to claim 9, further characterized by the steps of mixing a third flow of fuel into a third flow of air so as to form a third fuel/air mixture, and combusting said third fuel/air mixture by mixing said third fuel/air mixture into said further combusted gas, thereby raising the temperature of said third fuel/air mixture above its ignition temperature.
Claim 12
Dependent Claim
83 words
The method according to claim 11, further characterized in that the step of combusting said catalyzed fuel/air mixture occurs in a first combustion zone of a combustor, said first combustion zone disposed downstream from said catalyst, the step of mixing and combusting said second fuel/air mixture occurs in a second combustion zone disposed downstream from said first combustion zone, and the step of mixing and combusting said third fuel/air mixture occurs in a third combustion zone disposed downstream from said second combustion zone.
Claim 13
Dependent Claim
28 words
The method according to claim 9, further characterized by the step of heating said first fuel/air mixture comprises heating said first fuel/air mixture to at least approximately 400°C.
References Cited (Backward Citations)
US3928961A
Cited
US4072007A
Cited
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