US4335084A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for reducing NOx emissions from combustion processes
Assignee: KEY WEST HOLDINGS Inc
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Filing: 1981-06-19
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Granted: 1982-06-15
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Expires: 2001-06-19
Abstract
Abstract The present invention relates to a method for the noncatalytic reduction of NO x in combustion gases which method includes maintaining an excess of fuel to air during combustion, cooling the combustion gases to between 2400° F. and 3000° F., and injecting into the cooled gases ammonia in a ratio 1:1 to 1:4 NO x to NH 3 . After the ammonia has been injected to reduce the NO x , the gas is further cooled to between 1900° F. and 2300° F. and secondary air injected into the gases to complete combustion of the fuel.
Inventors
- 👤 Thomas R. Brogan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:29
CPC Classifications
F; F23; F23C; F23C6/00; F23C6/04; B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/54; B01D53/56
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
133 words
A method for reducing the NO x present in combustion gases which results from the combustion of fossil fuels with air, said method comprising the steps of a. controlling the air/fuel mixture for combustion to obtain fuel rich combustion gases in the combustion zone; b. maintaining or cooling the temperature of the combustion gas downstream of said combustion zone in a first zone at between about 2500° F. and 3000° F.; c. injecting ammonia in a molar ratio of 1:1 to 4:1 (NH 3 /NO x ) into the combustion gases at the first zone; d. reducing the temperature of the combustion gases at a second zone to between 1900° F. and 2400° F.; and e. injecting secondary air into the combustion gases at the second zone to complete combustion of the fuel.
Claim 2
Independent Claim
133 words
A method for reducing the NO x present in combustion gases which results from the combustion of fossil fuels with air, said method comprising the steps of a. controlling the air/fuel mixture for combustion to obtain fuel rich combustion gases in the combustion zone; b. maintaining or cooling the temperature of the combustion gas downstream of said combustion zone in a first zone at between about 2500° F. and 3000° F.; c. injecting ammonia in a molar ratio of 1:1 to 4:1 (NH 3 /NO x ) into the combustion gases at the first zone; d. reducing the temperature of the combustion gases at a second zone to between 1900° F. and 2400° F.; and e. injecting secondary air into the combustion gases at the second zone to complete combustion of the fuel.
Claim 3
Independent Claim
126 words
A method for reducing the NO x present in hot gases resulting from the combustion of fuel and oxidizer in a magnetohydrodynamic generator comprising the steps a. controlling the oxygen/fuel ratio of the combustion to obtain fuel rich combustion gases; b. slowly cooling the combustion gases in a first zone downstream of the MHD generator to between 2500° F. and 3000° F.; c. injecting ammonia in a molar ratio of 1:1 to 4:1 (NH 3 to NO x ) into said combustion gases at said first zone; d. reducing the temperature of the combustion gases at a second zone to between 1900° F. and 2400° F.; and e. injecting secondary air into the combustion gases at the second zone to complete the combustion of the fuel.
Claim 4
Independent Claim
126 words
A method for reducing the NO x present in hot gases resulting from the combustion of fuel and oxidizer in a magnetohydrodynamic generator comprising the steps a. controlling the oxygen/fuel ratio of the combustion to obtain fuel rich combustion gases; b. slowly cooling the combustion gases in a first zone downstream of the MHD generator to between 2500° F. and 3000° F.; c. injecting ammonia in a molar ratio of 1:1 to 4:1 (NH 3 to NO x ) into said combustion gases at said first zone; d. reducing the temperature of the combustion gases at a second zone to between 1900° F. and 2400° F.; and e. injecting secondary air into the combustion gases at the second zone to complete the combustion of the fuel.
Claim 5
Dependent Claim
25 words
The methods set forth in claim 1 and 2 wherein the temperature of said first and second zones are maintained at about 2700° F. respectively.
Claim 6
Dependent Claim
28 words
The methods set forth in claims 1, 2 and 3 wherein said molar ratio of ammonia to the initial oxides of nitrogen is between about 1.1 and 1.5.
Claim 7
Dependent Claim
29 words
The methods set forth in claims 1, 2 and 3 wherein said first and second zones are separated by a gas travel time of from 0.5 to 2 seconds.
Claim 8
Dependent Claim
22 words
The methods set forth in claims 1 and 2 wherein said ratio of air to fuel is about from 0.9 to 0.99.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-06-14 | 1985-12-14 | 1986-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-14 | 1989-12-14 | 1990-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-14 | 1993-12-14 | 1994-06-15 | $7700.00 | Window Closed / Lapsed |