Patent US4246853A successfully refreshed from Google Patents.
US4246853A
Expired / Lapsed
US
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Fuel firing method
Assignee: Combustion Engineering Inc
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Filing: 1979-08-27
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Granted: 1981-01-27
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Expires: 1999-08-27
Abstract
Abstract A method of operating a pulverized coal furnace wherein the coal is introduced with minimal oxygen through an intermediate zone of the furnace which also has a relatively low oxygen content. The carbon particles are projected into an upstream portion of the furnace where secondary air is introduced to burn the carbon particles. The combustion products pass upwardly through the intermediate zone to a downstream zone where tertiary air is added to complete combustion.
Inventors
- 👤 Arun K. Mehta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:22
CPC Classifications
F; F23; F23C; F23C6/00; F23C7/00; F23C7/02
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
136 words
A method of firing a nitrogen bearing fuel in a furnace having an upstream zone, an intermediate zone, and a downstream zone, comprising: introducing fuel into said furnace with a minimal amount of oxygen through said intermediate zone in a direction and at a velocity to carry the fuel particles into said upstream zone; introducing secondary air tangentially into said upstream zone, and burning most of the fuel therein, thereby forming combustion products; passing a major portion of the combustion products formed in said upstream zone through said intermediate zone, in the same areas as the passage of fuel therethru, to said downstream zone; and introducing tertiary air into said downstream zone to complete the burning of fuel, whereby fuel nitrogen is volatized in a hot oxygen deficient atmosphere, thus favoring the formation of diatomic nitrogen.
Claim 2
Independent Claim
136 words
A method of firing a nitrogen bearing fuel in a furnace having an upstream zone, an intermediate zone, and a downstream zone, comprising: introducing fuel into said furnace with a minimal amount of oxygen through said intermediate zone in a direction and at a velocity to carry the fuel particles into said upstream zone; introducing secondary air tangentially into said upstream zone, and burning most of the fuel therein, thereby forming combustion products; passing a major portion of the combustion products formed in said upstream zone through said intermediate zone, in the same areas as the passage of fuel therethru, to said downstream zone; and introducing tertiary air into said downstream zone to complete the burning of fuel, whereby fuel nitrogen is volatized in a hot oxygen deficient atmosphere, thus favoring the formation of diatomic nitrogen.
Claim 3
Dependent Claim
12 words
A method as in claim 1 wherein said fuel is a solid.
Claim 4
Dependent Claim
12 words
A method as in claim 2 wherein said fuel is pulverized coal.
Claim 5
Dependent Claim
19 words
A method as in claim 3 wherein said pulverized coal is introduced with a minimal amount of primary air.
Claim 6
Dependent Claim
47 words
A method as in claim 4 including also withdrawing a portion of the combustion products from the combustion product stream at a location downstream of said furnace; and using said withdrawn portion of combustion gases as the conveying medium to introduce the pulverized coal into said furnace.
Claim 7
Dependent Claim
34 words
A method as in claim 5 wherein said introduction of pulverized coal is in a direction such that the char particles remaining after devolatilization enters said upstream zone near the axis of said furnace.
Claim 8
Dependent Claim
21 words
A method as in claim 1, 5 or 6 including introducing fuel from locations substantially around the periphery of said furnace.
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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) | 1984-01-27 | 1984-07-28 | 1985-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-27 | 1988-07-28 | 1989-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-27 | 1992-07-28 | 1993-01-27 | $7700.00 | Window Closed / Lapsed |