EP0144094A1
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EP
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Nitrogen oxides decreasing combustion method
Assignee: Toshiba Corp
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Filing: 1984-12-06
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Granted: —
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Expires: 2004-12-06
Abstract
Abstract A nitrogen oxides decreasing combustion method which comprises; a first step of mixing a fuel and air with each other; a second step of bringing the mixture obtained in the the first step, into contact with a packed catalyst so as to cause a portion of the mixture to burn only through a catalytic reaction; and a third step of adding a fresh supply of the fuel to a stream obtained from the second step to form a mixed gas and causing the mixed gas to undergo non-catalytic thermal combustion; the temperature of said packed catalyst being lower than the ignition temperature of the mixture and the adiabatic flame temperature of said mixed gas being lower than a temperature at which the nitrogen oxides occur.
Inventors
- 👤 Tomiaki C/O Kabushiki Kaisha Toshiba Furuya
- 👤 Susumu C/O Kabushiki Kaisha Toshiba Yamanaka
- 👤 Terunobu C/O Kabushiki Kaisha Toshiba Hayata
- 👤 Junji C/O Kabushiki Kaisha Toshiba Koezuka
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 08:41
CPC Classifications
F; F23; F23C; F23C13/00; F02; F02C; F02C3/00; F02C3/20; F02C3/30; F23R; F23R3/00; F23R3/28; F23R3/34; F23R3/346; F23R3/40; Y; Y02; Y02E; Y02E20/00; Y02E20/16
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
125 words
A nitrogen oxides decreasing combustion method which comprises; a first step of mixing a fuel and air with each other; a second step of bringing the mixture obtained in the the first step, into contact with a packed catalyst so as to cause a portion of the mixture to burn only through a catalytic reaction; and a third step of adding a fresh supply of the fuel to a stream obtained from the second step to form a mixed gas and causing the mixed gas to undergo non-catalytic thermal combustion; the temperature of said packed catalyst being lower than the ignition temperature of the mixture and the adiabatic flame temperature of said mixed gas being lower than a temperature at which the nitrogen oxides occur.
Claim 2
Dependent Claim
125 words
A nitrogen oxides decreasing combustion method which comprises; a first step of mixing a fuel and air with each other; a second step of bringing the mixture obtained in the the first step, into contact with a packed catalyst so as to cause a portion of the mixture to burn only through a catalytic reaction; and a third step of adding a fresh supply of the fuel to a stream obtained from the second step to form a mixed gas and causing the mixed gas to undergo non-catalytic thermal combustion; the temperature of said packed catalyst being lower than the ignition temperature of the mixture and the adiabatic flame temperature of said mixed gas being lower than a temperature at which the nitrogen oxides occur.
Claim 3
Dependent Claim
17 words
The method according to Claim 1, wherein the temperature of the catalyst ranges from 300 to 900°C.
Claim 4
Dependent Claim
22 words
The method according to Claim 1, wherein the third step includes means for allowing the mixed gas stream to back-flow or stagnate.
Claim 5
Dependent Claim
14 words
The method according to Claim 1, wherein the third step includes an ignition source.
Claim 6
Dependent Claim
14 words
The method according to Claim 1, wherein the catalyst is comprised principally of palladium.
Claim 7
Dependent Claim
29 words
The method according to Claim 1, wherein the fuel to be added in the third step is supplied through one or more of pipes arranged through the catalyst bed.
Claim 8
Dependent Claim
23 words
The method according to Claim 1, wherein the length of the catalyst in the gas stream direction ranges from 3 to 15 cm.
Claim 9
Dependent Claim
23 words
The method according to Claim 1, wherein the temperature of the gas at a catalyst inlet ranges from 250 to 500 0 C.
Claim 10
Dependent Claim
21 words
The method according to Claim 1, wherein the gas flow velocity at a catalyst inlet ranges from 15 to 40 m/sec.
Claim 11
Dependent Claim
34 words
The method according to Claim 1, wherein the fuel concentration in the first step is controlled to give a temperature of 700 to 1300°C as adiabatic flame temperature when the fuel has been burnt.
Claim 12
Dependent Claim
20 words
The method according to Claim 1, wherein the fuel added in the third step is further added with a steam.
Claim 13
Dependent Claim
16 words
The method according to Claim 1, wherein the third step includes a swirl-forming or gyration-forming means.
Claim 14
Dependent Claim
14 words
The method according to Claim 12, wherein the swirl-forming means comprises a non-streamline body.
Claim 15
Dependent Claim
13 words
The method according to Claim 12, wherein the swirl-forming means comprises a swirler.
Claim 16
Dependent Claim
17 words
The method according to Claim 12, wherein the swirl-forming means comprises at least one of swirl-forming nozzles.
Claim 17
Dependent Claim
14 words
The method according to Claim 1, wherein the third step includes a dust-collection means.
Claim 18
Dependent Claim
15 words
The method according to Claim 1, wherein the third step includes a back-fire preventive means.
Claim 19
Dependent Claim
21 words
The method according to Claim 1, wherein the third step includes a flame-holding means equipped with a plurality of flow passages.
Claim 20
Dependent Claim
24 words
The method according to Claim 1, wherein the catalyst in the second step comprises a plurality of catalysts arranged in parallel to one another.
Claim 21
Dependent Claim
29 words
The method according to Claim 1, wherein the catalyst comprises a heat-resistant carrier supporting a silica-alumina mixture containing a noble metal and an oxide of a rare earth element.
Claim 22
Dependent Claim
60 words
The method according to Claim 20, wherein the catalyst comprises a former-stage catalyst and a latter-stage catalyst, and the particle size of the noble metal and the pore size of the silica-alumina carrier is controlled within the range of 50 to 200 A in the former-stage catalyst and within the range of 1000 to 2000 A in the latter-stage catalyst.
Claim 23
Dependent Claim
36 words
The method according to Claim 20, wherein the catalyst comprises a former-stage catalyst and a latter-stage catalyst, and the rare earth element comprises cerium contained in the former-stage catalyst and lanthanum contained in the latter-stage catalyst.
Claim 24
Dependent Claim
50 words
The method according to Claim 1, wherein the catalyst comprises a heat-resistant carrier supporting a noble metal and fine aluminum particles comprised of an oxide represented by the following formula: wherein M represents a rare earth element selected from the group consisting of samarium, gadolinium, cerium, lanthanum, Praseodymium and neodymium.
Claim 25
Dependent Claim
34 words
The method according to Claim 1, wherein the catalyst comprises a heat-resistant carrier and an alumina supported on the heat-resistant carrier and containing a noble metal, which has been subjected to a quenching treatment.
Claim 26
Dependent Claim
33 words
The method according to Claim 24, wherein the catalyst contains a rare earth metal selected from the group consisting of yttrium, cesium, lanthanum, neodymium, samarium and gadolinium, in the state of an alloy.
References Cited (Backward Citations)
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FR2179019A1
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GB1570180A
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