US3927627A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Steam generating system and method utilizing exhaust gas recirculation
Assignee: Foster Wheeler Energy Corp
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Filing: 1974-11-29
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Granted: 1975-12-23
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Expires: 1994-11-29
Abstract
Abstract A steam generating system and method in which a portion of the exhaust gases from a furnace section is passed through a duct system back into the furnace section to reduce the temperature in the furnace section. Air at ambient temperature is also passed directly into the duct system for cooling the exhaust gases before they are passed to the furnace section.
Inventors
- 👤 Frederick Milton Brunn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:19
CPC Classifications
F; F23; F23L; F23L15/00; F23C; F23C9/00; F23C9/08; Y; Y02; Y02E; Y02E20/00; Y02E20/34
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
101 words
A steam generating system comprising a furnace, means for passing at least a portion of the exhaust gases from the outlet section of said furnace back into the combustion section of said furnace, said means including a duct connecting said sections and a fan disposed in said duct, means for passing air at ambient temperature directly into said duct upstream of said fan for cooling said exhaust gases before they enter said fan, and means for passing preheated air into said duct downstream of said fan for mixing with said cooled exhaust gases before they are passed to said combustion section.
Claim 2
Dependent Claim
101 words
A steam generating system comprising a furnace, means for passing at least a portion of the exhaust gases from the outlet section of said furnace back into the combustion section of said furnace, said means including a duct connecting said sections and a fan disposed in said duct, means for passing air at ambient temperature directly into said duct upstream of said fan for cooling said exhaust gases before they enter said fan, and means for passing preheated air into said duct downstream of said fan for mixing with said cooled exhaust gases before they are passed to said combustion section.
Claim 3
Dependent Claim
65 words
The system of claim 1 wherein said means for passing preheated air into said duct comprises a preheater, means for passing a portion of the exhaust gases from said furnace section to said preheater, means for passing ambient air to said preheater where it passes in heat exchange with said exhaust gases to preheat said ambient air, and means connecting said preheater to said duct.
Claim 4
Dependent Claim
25 words
The system of claim 1 further comprising means to pass water in a heat exchange relation to said furnace to convert the water to steam.
Claim 5
Dependent Claim
48 words
The system of claim 1 further comprising a plurality of burners cooperating with openings formed in said combustion section of said furnace for combusting fuel in said combustion section, and a windbox extending over said burners, said duct connecting said outlet section of said furnace to said windbox.
Claim 6
Dependent Claim
159 words
A steam generating system comprising a furnace, a preheater, first duct means for passing a portion of the exhaust gases from the outlet section of said furnace to said preheater, means for introducing ambient air into said preheater where it passes in a heat exchange relation to said exhaust gases in said preheater to heat said ambient air, second duct means for passing said heated ambient air to the combustion section of said furnace, third duct means connecting said first duct means to said second duct means, a fan disposed in said third duct means for passing a portion of the exhaust gases from said first duct means to said second duct means for mixing with said heated ambient air before passing into said combustion section of said furnace, and means for passing air at ambient temperature directly into said third duct means upstream of said fan means for cooling said exhaust gases before they pass into said fan.
Claim 7
Dependent Claim
159 words
A steam generating system comprising a furnace, a preheater, first duct means for passing a portion of the exhaust gases from the outlet section of said furnace to said preheater, means for introducing ambient air into said preheater where it passes in a heat exchange relation to said exhaust gases in said preheater to heat said ambient air, second duct means for passing said heated ambient air to the combustion section of said furnace, third duct means connecting said first duct means to said second duct means, a fan disposed in said third duct means for passing a portion of the exhaust gases from said first duct means to said second duct means for mixing with said heated ambient air before passing into said combustion section of said furnace, and means for passing air at ambient temperature directly into said third duct means upstream of said fan means for cooling said exhaust gases before they pass into said fan.
Claim 8
Dependent Claim
25 words
The system of claim 5 further comprising means to pass water in a heat exchange relation to said furnace to convert the water to steam.
Claim 9
Dependent Claim
48 words
The system of claim 5 further comprising a plurality of burners cooperating with openings formed in said combustion section of said furnace for combusting fuel in said combustion section, and a windbox extending over said burners, said second duct means passing said heated ambient air to said windbox.
Claim 10
Independent Claim
76 words
A method for reducing the temperature in the combustion section of a furnace comprising the steps of passing at least a portion of the exhaust gases from the outlet section of said furnace through a duct and back into the combustion section of said furnace, passing air at ambient temperature directly into said duct for cooling said exhaust gases, and mixing preheated air with said cooled exhaust gaseS before they are passed to said combustion section.
Claim 11
Independent Claim
76 words
A method for reducing the temperature in the combustion section of a furnace comprising the steps of passing at least a portion of the exhaust gases from the outlet section of said furnace through a duct and back into the combustion section of said furnace, passing air at ambient temperature directly into said duct for cooling said exhaust gases, and mixing preheated air with said cooled exhaust gaseS before they are passed to said combustion section.
Claim 12
Dependent Claim
45 words
The method of claim 8 further comprising the steps of passing a portion of the exhaust gases from said furnace section to a preheater, passing ambient air to said preheater where it passes in heat exchange with said exhaust gases to form said preheated air.
Claim 13
Dependent Claim
30 words
The method of claim 8 further comprising the steps of passing water in a heat exchange relation to said combustion section of said furnace to convert the water to steam.
Claim 14
Independent Claim
97 words
A method for reducing the temperature in the combustion section of a furnace comprising the steps of passing a portion of the exhaust gases from the outlet section of said furnace in a heat exchange relation to ambient air to heat said ambient air, passing said heated ambient air to said combustion section of said furnace, mixing a portion of the exhaust gases from said outlet section with said heated ambient air before the latter is passed into said combustion section, and cooling said latter portion of exhaust gases before they are mixed with said ambient air.
Claim 15
Independent Claim
97 words
A method for reducing the temperature in the combustion section of a furnace comprising the steps of passing a portion of the exhaust gases from the outlet section of said furnace in a heat exchange relation to ambient air to heat said ambient air, passing said heated ambient air to said combustion section of said furnace, mixing a portion of the exhaust gases from said outlet section with said heated ambient air before the latter is passed into said combustion section, and cooling said latter portion of exhaust gases before they are mixed with said ambient air.
Claim 16
Dependent Claim
30 words
The method of claim 11 further comprising the steps of passing water in a heat exchange relation to said combustion section of said furnace to convert the water to steam.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-22 | 1979-06-23 | 1979-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-22 | 1983-06-23 | 1983-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-22 | 1987-06-23 | 1987-12-23 | $7700.00 | Window Closed / Lapsed |