Patent US5350293A successfully refreshed from Google Patents.
US5350293A
Expired / Lapsed
US
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Method for two-stage combustion utilizing forced internal recirculation
Assignee: Gas Technology Institute
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Filing: 1993-07-20
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Granted: 1994-09-27
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Expires: 2013-07-20
Abstract
Abstract A method for two-stage combustion in which a mixture of fuel and primary combustion air is burned in a primary combustion zone, the primary combustion air comprising less than a stoichiometric requirement for complete combustion of the fuel, a portion of cooled partial combustion products formed in the primary combustion zone is recirculated from a downstream end of the primary combustion zone to an upstream end of the primary combustion zone, secondary combustion air is introduced into a secondary combustion zone downstream of the primary combustion zone, a portion of the heat from the primary combustion zone is removed, cooling the partial combustion products formed therein, and the heat is transported away from the combustion process. An apparatus for two-stage combustion in accordance with this method is also disclosed.
Inventors
- 👤 Mark J. Khinkis
- 👤 Hamid A. Abbasi
- 👤 David F. Cygan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 03:55
CPC Classifications
F; F23; F23C; F23C6/00; F23C6/04; F23C6/045; F23C9/00; F23C9/006; F23C2203/00; F23C2203/10; F23C2900/00; F23C2900/06041; F23C2900/09001; F23C2900/13002; Y; Y02; Y02E; Y02E20/00; Y02E20/30
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
120 words
A method for two-stage combustion comprising the steps of: burning a mixture of fuel and primary combustion air in a primary combustion zone, said primary combustion air comprising less than a stoichiometric requirement for complete combustion of said fuel, forming partial combustion products; removing a first portion of heat from said primary combustion zone, cooling said partial combustion products; recirculating a portion of said cooled partial combustion products from a downstream end of said primary combustion zone to an upstream end of said primary combustion zone; introducing secondary combustion air into a secondary combustion zone downstream of said primary combustion zone, completing combustion of said partial combustion products; and removing a second portion of heat from said secondary combustion zone.
Claim 2
Independent Claim
120 words
A method for two-stage combustion comprising the steps of: burning a mixture of fuel and primary combustion air in a primary combustion zone, said primary combustion air comprising less than a stoichiometric requirement for complete combustion of said fuel, forming partial combustion products; removing a first portion of heat from said primary combustion zone, cooling said partial combustion products; recirculating a portion of said cooled partial combustion products from a downstream end of said primary combustion zone to an upstream end of said primary combustion zone; introducing secondary combustion air into a secondary combustion zone downstream of said primary combustion zone, completing combustion of said partial combustion products; and removing a second portion of heat from said secondary combustion zone.
Claim 3
Dependent Claim
13 words
A method in accordance with claim 1, wherein said fuel is natural gas.
Claim 4
Dependent Claim
25 words
A method in accordance with claim 1, wherein the amount of said secondary combustion air is less than the amount of said primary combustion air.
Claim 5
Dependent Claim
41 words
A method in accordance with claim 1, wherein a diluent selected from the group consisting of recirculated flue gases, steam, water, nitrogen and mixtures thereof is introduced into at least one of said primary combustion zone and said secondary combustion zone.
Claim 6
Dependent Claim
29 words
A method in accordance with claim 1, wherein at least a portion of said mixture of fuel and primary combustion air is catalytically combusted in said primary combustion zone.
Claim 7
Dependent Claim
116 words
In a process for two-stage combustion in which a mixture of fuel and primary combustion air is burned in a primary combustion zone, said primary combustion air comprising less than a stoichiometric requirement for complete combustion of said fuel, a portion of cooled partial combustion products formed in said primary combustion zone is recirculated from a downstream end of said primary combustion zone to an upstream end of said primary combustion zone, and secondary combustion air is introduced into a secondary combustion zone downstream of said primary combustion zone, the improvement comprising: removing a portion of heat from said primary combustion zone, cooling said partial combustion products; and transporting said heat away from said combustion process.
Claim 8
Dependent Claim
116 words
In a process for two-stage combustion in which a mixture of fuel and primary combustion air is burned in a primary combustion zone, said primary combustion air comprising less than a stoichiometric requirement for complete combustion of said fuel, a portion of cooled partial combustion products formed in said primary combustion zone is recirculated from a downstream end of said primary combustion zone to an upstream end of said primary combustion zone, and secondary combustion air is introduced into a secondary combustion zone downstream of said primary combustion zone, the improvement comprising: removing a portion of heat from said primary combustion zone, cooling said partial combustion products; and transporting said heat away from said combustion process.
Claim 9
Dependent Claim
13 words
A process in accordance with claim 6, wherein said fuel is natural gas.
Claim 10
Dependent Claim
25 words
A process in accordance with claim 6, wherein the amount of said secondary combustion air is less than the amount of said primary combustion air.
Claim 11
Dependent Claim
41 words
A process in accordance with claim 6, wherein a diluent selected from the group consisting of recirculated flue gases, steam, water, nitrogen and mixtures thereof is introduced into at least one of said primary combustion zone and said secondary combustion zone.
Claim 12
Dependent Claim
29 words
A process in accordance with claim 6, wherein at least a portion of said mixture of fuel and primary combustion air is catalytically combusted in said primary combustion zone.
Claim 13
Independent Claim
130 words
An apparatus for two-stage combustion comprising: a combustion chamber side wall connected to a combustion chamber end wall, said combustion chamber walls enclosing a combustion chamber, said combustion chamber having a primary combustion zone and a secondary combustion zone, said secondary combustion zone disposed downstream of said primary combustion zone; means for introducing a fuel and primary combustion air into said primary combustion zone; means for removing a first portion of heat from said primary combustion zone; recirculation means for recirculating a portion of partial combustion products from a downstream end of said primary combustion zone to an upstream end of said primary combustion zone; means for introducing secondary combustion air into said secondary combustion zone; and means for removing a second portion of heat from said secondary combustion zone.
Claim 14
Independent Claim
130 words
An apparatus for two-stage combustion comprising: a combustion chamber side wall connected to a combustion chamber end wall, said combustion chamber walls enclosing a combustion chamber, said combustion chamber having a primary combustion zone and a secondary combustion zone, said secondary combustion zone disposed downstream of said primary combustion zone; means for introducing a fuel and primary combustion air into said primary combustion zone; means for removing a first portion of heat from said primary combustion zone; recirculation means for recirculating a portion of partial combustion products from a downstream end of said primary combustion zone to an upstream end of said primary combustion zone; means for introducing secondary combustion air into said secondary combustion zone; and means for removing a second portion of heat from said secondary combustion zone.
Claim 15
Dependent Claim
43 words
An apparatus in accordance with claim 11, wherein said means for introducing said fuel and said primary combustion air into said primary combustion zone comprise means for introducing a mixture of said fuel and said primary combustion air into said primary combustion zone.
Claim 16
Dependent Claim
52 words
An apparatus in accordance with claim 11, wherein said means for introducing said secondary combustion air into said secondary combustion zone comprises a nozzle extending through said combustion chamber end wall and into said secondary combustion zone, said combustion chamber end wall disposed at an upstream end of said primary combustion zone.
Claim 17
Dependent Claim
59 words
An apparatus in accordance with claim 13, wherein said recirculation means comprises said nozzle and a recirculation wall disposed in said primary combustion zone at a distance from said combustion chamber end wall and said combustion chamber side wall and surrounding said nozzle at a distance from said nozzle, forming an annulus between said recirculation wall and said nozzle.
Claim 18
Dependent Claim
49 words
An apparatus in accordance with claim 11, wherein said recirculation means comprises a recirculation wall disposed in said primary combustion zone at a distance from said combustion chamber side wall and said combustion chamber end wall, forming an annulus between said recirculation wall and said combustion chamber side wall.
Claim 19
Dependent Claim
46 words
An apparatus in accordance with claim 15, wherein said means for introducing said fuel and primary combustion air into said primary combustion zone comprises a nozzle secured to said combustion chamber end wall and extending through said combustion chamber end wall into said primary combustion zone.
Claim 20
Dependent Claim
15 words
An apparatus in accordance with claim 14 further comprising means for cooling said recirculation wall.
Claim 21
Dependent Claim
15 words
An apparatus in accordance with claim 15 further comprising means for cooling said recirculation wall.
Claim 22
Dependent Claim
30 words
An apparatus in accordance with claim 17, wherein said means for cooling said recirculation wall comprises means for circulating a coolant within at least a portion of said recirculation wall.
Claim 23
Dependent Claim
19 words
An apparatus in accordance with claim 11 further comprising means for stabilizing a flame in said primary combustion zone.
Claim 24
Dependent Claim
29 words
An apparatus in accordance with claim 20, wherein said means for stabilizing a flame in said primary combustion zone comprises a combustion catalyst disposed within said primary combustion zone.
References Cited (Backward Citations)
US964031A
Cited
US3097686A
Cited
US3540821A
Cited
US3837788A
Cited
US3760776A
Cited
US4021188A
Cited
US4004875A
Cited
US4007001A
Cited
US4395223A
Cited
US4445842A
Cited
US4575332A
Cited
US4629413A
Cited
US4656972A
Cited
US4699071A
Cited
US4659305A
Cited
US4995807A
Cited
US5044932A
Cited
US5092761A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-09-26 | 1998-03-28 | 1998-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-09-26 | 2002-03-28 | 2002-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-09-26 | 2006-03-28 | 2006-09-27 | $7700.00 | Window Closed / Lapsed |