US5078064A
Expired / Lapsed
US
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Apparatus and method of lowering NOx emissions using diffusion processes
Assignee: Gas Technology Institute
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Filing: 1990-12-07
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Granted: 1992-01-07
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Expires: 2010-12-07
Abstract
Abstract An apparatus and method for reducing nitrogen oxide emissions from furnace flue gas is provided in which natural gas or other fluid fuel which has little or no fixed nitrogen is introduced into the upper portion of the furnace. The fuel diffuses by laminar or turbulent diffusion into oxygen-rich flue gas where it reacts with oxygen and nitric oxide to form CO2, H2O and N2, thus reducing the nitrogen oxide emissions from the furnace. In this manner, the amount of nitrogen oxide in the flue gas is reduced. The apparatus and method can be easily applied to new furnaces or retrofitted on existing furnaces.
Inventors
- 👤 Bernard P. Breen
- 👤 Steven E. Winberg
- 👤 James E. Gabrielson
- 👤 James C. McMichael
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:49
CPC Classifications
F; F23; F23C; F23C1/00; F23C1/12; Y; Y02; Y02E; Y02E20/00; Y02E20/34
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
99 words
An improved apparatus for reducing nitrogen oxide in flue gas in a combustion furnace burning at least one of coal and coke having a primary combustion zone wherein the improvement comprises: means forming at least one fuel introducing device attached to the furnace above the primary combustion zone which introduces into said flue gas a steady stream of fluid fuel which diffuses into said flue gas, said fluid fuel being selected from the group of fluids consisting of natural gas, hydrogen, C x H y compounds and C x H y O z compounds and mixtures of said fluids.
Claim 2
Dependent Claim
99 words
An improved apparatus for reducing nitrogen oxide in flue gas in a combustion furnace burning at least one of coal and coke having a primary combustion zone wherein the improvement comprises: means forming at least one fuel introducing device attached to the furnace above the primary combustion zone which introduces into said flue gas a steady stream of fluid fuel which diffuses into said flue gas, said fluid fuel being selected from the group of fluids consisting of natural gas, hydrogen, C x H y compounds and C x H y O z compounds and mixtures of said fluids.
Claim 3
Dependent Claim
39 words
The apparatus of claim 1 wherein said fuel introducing device is positioned to introduce said fuel into a region of said furnace wherein said flue gas is at a temperature in the range of 2100° F. to 2400° F.
Claim 4
Dependent Claim
36 words
The apparatus of claim 1 wherein said fuel introducing device are sized and provided in sufficient numbers to promote reaction between said fuel and said nitrogen oxide to provide a substantial reduction of said nitrogen oxide.
Claim 5
Dependent Claim
13 words
The apparatus of claim 1 wherein said fuel introducing device is a pipe.
Claim 6
Dependent Claim
14 words
The apparatus of claim 1 wherein said fuel introducing device is an annular opening.
Claim 7
Dependent Claim
13 words
The apparatus of claim 1 wherein said fuel introducing device is an orifice.
Claim 8
Dependent Claim
13 words
The apparatus of claim 1 wherein said fuel introducing device is a nozzle.
Claim 9
Dependent Claim
14 words
The apparatus of claim 1 wherein said fuel introducing device is a porous device.
Claim 10
Dependent Claim
21 words
The apparatus of claim 1 wherein said fuel is introduced through 100 to 1,000,000 holes of less than 1/4 inch diameter.
Claim 11
Dependent Claim
14 words
The apparatus of claim 1 wherein said fuel is introduced through a ceramic sock.
Claim 12
Dependent Claim
15 words
The apparatus of claim 1 wherein said combustion furnace is part of a steam generator.
Claim 13
Dependent Claim
15 words
The apparatus of claim 1 wherein said combustion furnace is part of a process heater.
Claim 14
Dependent Claim
27 words
The apparatus of claim 1 wherein said combustion furnace is of the type which heats directly, or, supplies hot gases to heat directly, materials in a process.
Claim 15
Independent Claim
14 words
The apparatus of claims 1 wherein said combustion furnace is part of a heater.
Claim 16
Dependent Claim
14 words
The apparatus of claim 1 wherein said combustion furnace is part of an incinerator.
Claim 17
Dependent Claim
16 words
An apparatus in claim 1 wherein the fuel is introduced in a direction other than horizontally.
Claim 18
Dependent Claim
26 words
An apparatus in claim 1 wherein the fuel introducing devices are capable of being reoriented so as to improve the operation by redirecting the fuel flow.
Claim 19
Dependent Claim
86 words
An improved apparatus for reducing nitrogen oxide in the flue gas in a furnace having a convective zone wherein the improvement comprises: means forming at least one-fuel introducing device in or after said convective zone which introduces into said flue gas a steady stream of fluid fuel which diffuses into said flue gas, said fluid fuel being selected from the group of fluids consisting of natural gas, hydrogen, C x H y compounds and C x H y O z compounds and mixtures of said fluids.
Claim 20
Dependent Claim
86 words
An improved apparatus for reducing nitrogen oxide in the flue gas in a furnace having a convective zone wherein the improvement comprises: means forming at least one-fuel introducing device in or after said convective zone which introduces into said flue gas a steady stream of fluid fuel which diffuses into said flue gas, said fluid fuel being selected from the group of fluids consisting of natural gas, hydrogen, C x H y compounds and C x H y O z compounds and mixtures of said fluids.
Claim 21
Dependent Claim
37 words
The apparatus of claim 18 wherein said fuel introducing devices are sized and provided in sufficient numbers to promote the reaction between said fuel and said nitrogen oxide to provide a substantial reduction in said nitrogen oxide.
Claim 22
Dependent Claim
10 words
The apparatus of claim 18 wherein said fuel is hydrogen.
Claim 23
Dependent Claim
14 words
The apparatus of claim 18 wherein at least part of said fuel is hydrogen.
Claim 24
Dependent Claim
14 words
The apparatus of claim 18 wherein said fuel introducing device is a porous body.
Claim 25
Dependent Claim
25 words
The apparatus of claim 18 wherein said fuel inducing device includes a porous member having 100 to 1,000,000 holes of less than 1/4 inch diameter.
Claim 26
Dependent Claim
14 words
The apparatus of claim 18 wherein said fuel introducing device is a ceramic sock.
Claim 27
Dependent Claim
13 words
The apparatus of claim 18 wherein said fuel introducing device is a pipe.
Claim 28
Dependent Claim
14 words
The apparatus of claim 18 wherein said fuel introducing device is an annular opening.
Claim 29
Dependent Claim
13 words
The apparatus of claim 18 wherein said fuel introducing device is an orifice.
Claim 30
Dependent Claim
13 words
The apparatus of claim 18 wherein said fuel introducing device is a nozzle.
Claim 31
Dependent Claim
14 words
The apparatus of claim 18 wherein said furnace is part of a steam generator.
Claim 32
Dependent Claim
13 words
The apparatus of claim 18 wherein said furnace is part of a heater.
Claim 33
Dependent Claim
12 words
An apparatus of claim 18 wherein the fuel is not introduced vertically.
Claim 34
Dependent Claim
16 words
An apparatus as in claim 18 wherein the fuel introducing device can be reoriented as needed.
Claim 35
Dependent Claim
92 words
An in-furnace method for reducing oxygen in flue gas comprising the step of: injecting a stream of fluid fuel into said flue gas so it diffuses therein, said fluid fuel being selected from the group of fluids consisting of natural gas, hydrogen, C x H y compounds, C x H y O z compounds and mixtures primarily of those compounds, in sufficient quantity to promote a reaction between said nitrogen oxide in the flue gas and said fluid fuel, so as to substantially reduce said nitrogen oxide content of said flue gas.
Claim 36
Dependent Claim
92 words
An in-furnace method for reducing oxygen in flue gas comprising the step of: injecting a stream of fluid fuel into said flue gas so it diffuses therein, said fluid fuel being selected from the group of fluids consisting of natural gas, hydrogen, C x H y compounds, C x H y O z compounds and mixtures primarily of those compounds, in sufficient quantity to promote a reaction between said nitrogen oxide in the flue gas and said fluid fuel, so as to substantially reduce said nitrogen oxide content of said flue gas.
Claim 37
Dependent Claim
15 words
The method of claim 33 wherein the fluid fuel is introduced in the upper furnace.
Claim 38
Dependent Claim
22 words
The method of claim 33 wherein said furnace has a convective zone, and wherein fluid fuel is introduced in said convective zone.
Claim 39
Dependent Claim
21 words
The method of claim 33 wherein said flue gas has a temperature within the range of 2100° F. to 2400° F.
Claim 40
Dependent Claim
52 words
The method of claim 33 wherein the fluid fuel forms diapirs of fuel moving with a flow of the flue gas as influenced by buoyancy of one gas within another and by other flow, viscous, and thermal effects so the diapirs move with the flue gas and diffusion between them is slow.
Claim 41
Dependent Claim
90 words
An improved apparatus for reducing nitrogen oxide in flue gas in a combustion furnace having a primary combustion zone wherein the improvement comprises at least one porous device for introducing fuel attached to the furnace above the primary combustion zone which introduces into said flue gas a stream of fluid fuel which diffuses into said flue gas, said fluid fuel being selected from the group of fluids consisting of natural gas, hydrogen, C x H y compounds and C x H y O z compounds and mixtures of said fluids.
Claim 42
Dependent Claim
90 words
An improved apparatus for reducing nitrogen oxide in flue gas in a combustion furnace having a primary combustion zone wherein the improvement comprises at least one porous device for introducing fuel attached to the furnace above the primary combustion zone which introduces into said flue gas a stream of fluid fuel which diffuses into said flue gas, said fluid fuel being selected from the group of fluids consisting of natural gas, hydrogen, C x H y compounds and C x H y O z compounds and mixtures of said fluids.
Claim 43
Dependent Claim
21 words
The apparatus of claim 38 wherein said fuel is introduced through 100 to 1,000,000 holes of less than 1/4 inch diameter.
Claim 44
Dependent Claim
14 words
The apparatus of claim 38 wherein said fuel is introduced through a ceramic sock.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1995-01-06 | 1995-07-08 | 1996-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-01-06 | 1999-07-08 | 2000-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-01-06 | 2003-07-08 | 2004-01-07 | $7700.00 | Window Closed / Lapsed |