US6718772B2
Expired / Lapsed
US
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Method of thermal NOx reduction in catalytic combustion systems
Assignee: Kawasaki Motors Ltd
•
Filing: 2001-10-26
•
Granted: 2004-04-13
•
Expires: 2021-10-26
Abstract
Abstract Methods and apparatus, both devices and systems, for control of Zeldovich (thermal) NOx production in catalytic combustion systems during combustion of liquid or gaseous fuels in the post catalytic sections of gas turbines by reducing combustion residence time in the HC zone through control of the HC Wave, principally by adjusting the catalyst inlet temperature. As the fuel/air mixture inlet temperature (to the catalyst) is reduced, the HC Wave moves downstream (longer ignition delay time), shortens the residence time at high temperature, thereby reducing thermal NOx production. The countervailing increase in CO production by longer ignition delay times can be limited by selectively locating the HC Wave so that thermal NOx is reduced while power output and low CO production is maintained. NOx is reduced to on the order of <3 ppm, and preferably <2 ppm, while CO is maintained <100 ppm, typically <50 ppm, and preferably <5-10 ppm.
Inventors
- 👤 Ralph A. Dalla Betta
- 👤 Marco A. Velasco
- 👤 David K. Yee
- 👤 Sarento G. Nickolas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:01
CPC Classifications
F; F23; F23R; F23R3/00; F23R3/40
Claims Analysis
Total Claims: 59
Claim 1
Independent Claim
78 words
A method for operating catalytic combustor, comprising: catalytically combusting a fuel-air mixture in a combustor, wherein at least a portion of the fuel-air mixture is combusted in a homogeneous combustion wave within a post catalyst burnout zone located downstream of a catalyst to form hot combustion gases; and controlling the residence time of the hot combustion gases within the post catalyst burn out zone to control the production of thermal NOx while maintaining a substantially constant adiabatic temperature.
Claim 2
Independent Claim
78 words
A method for operating catalytic combustor, comprising: catalytically combusting a fuel-air mixture in a combustor, wherein at least a portion of the fuel-air mixture is combusted in a homogeneous combustion wave within a post catalyst burnout zone located downstream of a catalyst to form hot combustion gases; and controlling the residence time of the hot combustion gases within the post catalyst burn out zone to control the production of thermal NOx while maintaining a substantially constant adiabatic temperature.
Claim 3
Dependent Claim
28 words
The method of claim 1 wherein the residence time is controlled by controlling the location of the homogeneous combustion wave with respect to an outlet of the combustor.
Claim 4
Dependent Claim
22 words
The method of claim 1 , wherein the residence time is controlled to reduce the production of NOx below a preselected level.
Claim 5
Dependent Claim
13 words
The method of claim 3 , wherein the preselected level is 3 ppm.
Claim 6
Dependent Claim
13 words
The method of claim 3 , wherein the preselected level is 2 ppm.
Claim 7
Dependent Claim
33 words
The method of claim 1 , wherein controlling the residence time of the hot combustion gases within the post catalyst burnout zone further includes controlling the production of CO below a preselected level.
Claim 8
Dependent Claim
18 words
The method of claim 6 , wherein the preselected level of the production of CO is 100 ppm.
Claim 9
Dependent Claim
18 words
The method of claim 6 , wherein the preselected level of the production of CO is 10 ppm.
Claim 10
Dependent Claim
31 words
The method of claim 1 , wherein the residence time is controlled to reduce the production of NOx below a preselected level and the production of CO below a preselected level.
Claim 11
Dependent Claim
48 words
The method of claim 1 , wherein, the hot combustion gases have a temperature above 1450° C. during the residence time, and the residence time is controlled such that the production of NOx is below approximately 3 ppm and the production of CO is below approximately 100 ppm.
Claim 12
Dependent Claim
22 words
The method of claim 10 , wherein NOx is produced below approximately 2 ppm and CO is produced below approximately 10 ppm.
Claim 13
Dependent Claim
33 words
The method of claim 1 , wherein the controlling includes monitoring at least one characteristic of at least one of the fuel-air mixture and the hot combustion gas to control the residence time.
Claim 14
Dependent Claim
39 words
The method of claim 12 , wherein the monitoring includes sensing at least one of fuel amount, air flow rate, fuel feed rate, fuel-air mixture temperature, hot combustion gas temperature, the production of NOx, and the production of CO.
Claim 15
Dependent Claim
38 words
The method of claim 1 , wherein the production of NOx and the production of CO are monitored, and the residence time is controlled to reduce NOx below a preselected level while maintaining CO below a preselected level.
Claim 16
Dependent Claim
33 words
The method of claim 1 , wherein controlling the residence time includes adjusting the catalyst outlet gas temperature to control the delay time for ignition of the fuel in the homogenous combustion wave.
Claim 17
Dependent Claim
25 words
The method of claim 15 , wherein the catalyst outlet gas temperature is adjusted by controlling the temperature of the fuel-air mixture entering the catalyst.
Claim 18
Dependent Claim
103 words
The method of claim 16 , wherein the combustor includes a preburner upstream of the catalyst, and the temperature of at least one of the fuel-air mixture and the catalyst outlet gas is controlled by at least one of: adjusting the fraction of air bypassing the catalyst, adjusting the fuel supplied to the combustor by proportioning the fuel supplied between the catalyst and the preburner, adjusting air input to the preburner, adjusting the composition of the fuel by introduction of components that affect the ignition delay time, and introducing water in at least one of upstream of the combustor and in the combustor.
Claim 19
Dependent Claim
53 words
The method of claim 17 , wherein the temperature of the hot combustion gas is maintained in a predetermined range for energy extraction and the fuel supplied to the preburner is controlled to move the homogenous combustion wave to a location to reduce NOx production while maintaining CO production below about 50 ppm.
Claim 20
Dependent Claim
62 words
The method of claim 1 , wherein the controlling includes utilizing an empirical model of the operation of the combustor under a range of operating parameters, calculating the residence time of the hot combustion gases in the combustor as the parameters change, and setting system operating controls to selectively position the location of the homogeneous wave to achieve a desired residence time.
Claim 21
Independent Claim
95 words
A method for operating a catalytic combustor, comprising: catalytically combusting a fuel-air mixture in a combustor, wherein at least a portion of the fuel-air mixture is combusted in a homogeneous combustion wave within a post catalyst burnout zone located downstream of a catalyst to form hot combustion gases; and controlling the residence time of the hot combustion gases within the post catalyst burn out zone to control the production of thermal NOx, wherein the residence time is controlled by controlling the location of the homogeneous combustion wave with respect to an outlet of the combustor.
Claim 22
Independent Claim
95 words
A method for operating a catalytic combustor, comprising: catalytically combusting a fuel-air mixture in a combustor, wherein at least a portion of the fuel-air mixture is combusted in a homogeneous combustion wave within a post catalyst burnout zone located downstream of a catalyst to form hot combustion gases; and controlling the residence time of the hot combustion gases within the post catalyst burn out zone to control the production of thermal NOx, wherein the residence time is controlled by controlling the location of the homogeneous combustion wave with respect to an outlet of the combustor.
Claim 23
Dependent Claim
22 words
The method of claim 20 , wherein the residence time is controlled to reduce the production of NOx below a preselected level.
Claim 24
Dependent Claim
13 words
The method of claim 21 , wherein the preselected level is 3 ppm.
Claim 25
Dependent Claim
13 words
The method of claim 21 , wherein the preselected level is 2 ppm.
Claim 26
Dependent Claim
33 words
The method of claim 20 , wherein controlling the residence time of the hot combustion gases within the post catalyst burnout zone further includes controlling the production of CO below a preselected level.
Claim 27
Dependent Claim
18 words
The method of claim 24 , wherein the preselected level of the production of CO is 100 ppm.
Claim 28
Dependent Claim
18 words
The method of claim 24 , wherein the preselected level of the production of CO is 10 ppm.
Claim 29
Dependent Claim
31 words
The method of claim 20 , wherein the residence time is controlled to reduce the production of NOx below a preselected level and the production of CO below a preselected level.
Claim 30
Dependent Claim
48 words
The method of claim 20 , wherein, the hot combustion gases have a temperature above 1450° C. during the residence time, and the residence time is controlled such that the production of NOx is below approximately 3 ppm and the production of CO is below approximately 100 ppm.
Claim 31
Dependent Claim
22 words
The method of claim 28 , wherein NOx is produced below approximately 2 ppm and CO is produced below approximately 10 ppm.
Claim 32
Dependent Claim
33 words
The method of claim 20 , wherein the controlling includes monitoring at least one characteristic of at least one of the fuel-air mixture and the hot combustion gas to control the residence time.
Claim 33
Dependent Claim
39 words
The method of claim 30 , wherein the monitoring includes sensing at least one of fuel amount, air flow rate, fuel feed rate, fuel-air mixture temperature, hot combustion gas temperature, the production of NOx, and the production of CO.
Claim 34
Dependent Claim
38 words
The method of claim 20 , wherein the production of NOx and the production of CO are monitored, and the residence time is controlled to reduce NOx below a preselected level while maintaining CO below a preselected level.
Claim 35
Dependent Claim
33 words
The method of claim 20 , wherein controlling the residence time includes adjusting the catalyst outlet gas temperature to control the delay time for ignition of the fuel in the homogenous combustion wave.
Claim 36
Dependent Claim
25 words
The method of claim 33 , wherein the catalyst outlet gas temperature is adjusted by controlling the temperature of the fuel-air mixture entering the catalyst.
Claim 37
Dependent Claim
103 words
The method of claim 34 , wherein the combustor includes a preburner upstream of the catalyst, and the temperature of at least one of the fuel-air mixture and the catalyst outlet gas is controlled by at least one of: adjusting the fraction of air bypassing the catalyst, adjusting the fuel supplied to the combustor by proportioning the fuel supplied between the catalyst and the preburner, adjusting air input to the preburner, adjusting the composition of the fuel by introduction of components that affect the ignition delay time, and introducing water in at least one of upstream of the combustor and in the combustor.
Claim 38
Dependent Claim
53 words
The method of claim 35 , wherein the temperature of the hot combustion gas is maintained in a predetermined range for energy extraction and the fuel supplied to the preburner is controlled to move the homogenous combustion wave to a location to reduce NOx production while maintaining CO production below about 50 ppm.
Claim 39
Dependent Claim
62 words
The method of claim 20 , wherein the controlling includes utilizing an empirical model of the operation of the combustor under a range of operating parameters, calculating the residence time of the hot combustion gases in the combustor as the parameters change, and setting system operating controls to selectively position the location of the homogeneous wave to achieve a desired residence time.
Claim 40
Independent Claim
99 words
A method for operating a catalytic combustor, comprising: catalytically combusting a fuel-air mixture in a combustor, wherein at least a portion of the fuel-air mixture is combusted in a homogeneous combustion wave within a post catalyst burnout zone located downstream of a catalyst to form hot combustion gases; and controlling the residence time of the hot combustion gases within the post catalyst burn out zone to control the production of thermal NOx, wherein controlling the residence time includes adjusting the catalyst outlet gas temperature to control the delay time for ignition of the fuel in the homogenous combustion wave.
Claim 41
Independent Claim
99 words
A method for operating a catalytic combustor, comprising: catalytically combusting a fuel-air mixture in a combustor, wherein at least a portion of the fuel-air mixture is combusted in a homogeneous combustion wave within a post catalyst burnout zone located downstream of a catalyst to form hot combustion gases; and controlling the residence time of the hot combustion gases within the post catalyst burn out zone to control the production of thermal NOx, wherein controlling the residence time includes adjusting the catalyst outlet gas temperature to control the delay time for ignition of the fuel in the homogenous combustion wave.
Claim 42
Dependent Claim
23 words
The method of claim 38 , wherein the catalyst outlet gas temperature is adjusted by controlling the temperature of the entering the catalyst.
Claim 43
Dependent Claim
28 words
The method of claim 38 wherein the residence time is controlled by controlling the location of the homogeneous combustion wave with respect to an outlet of the combustor.
Claim 44
Dependent Claim
22 words
The method of claim 38 , wherein the residence time is controlled to reduce the production of NOx below a preselected level.
Claim 45
Dependent Claim
13 words
The method of claim 41 , wherein the preselected level is 3 ppm.
Claim 46
Dependent Claim
13 words
The method of claim 41 , wherein the preselected level is 2 ppm.
Claim 47
Dependent Claim
33 words
The method of claim 38 , wherein controlling the residence time of the hot combustion gases within the post catalyst burnout zone further includes controlling the production of CO below a preselected level.
Claim 48
Dependent Claim
18 words
The method of claim 44 , wherein the preselected level of the production of CO is 100 ppm.
Claim 49
Dependent Claim
18 words
The method of claim 44 , wherein the preselected level of the production of CO is 10 ppm.
Claim 50
Dependent Claim
31 words
The method of claim 38 , wherein the residence time is controlled to reduce the production of NOx below a preselected level and the production of CO below a preselected level.
Claim 51
Independent Claim
44 words
The method wherein, the hot combustion gases have a temperature above 1450° C during the residence time, and the residence time is controlled such that the production of NOx is below approximately 3 ppm and the production of CO is below approximately 100 ppm.
Claim 52
Independent Claim
44 words
The method wherein, the hot combustion gases have a temperature above 1450° C during the residence time, and the residence time is controlled such that the production of NOx is below approximately 3 ppm and the production of CO is below approximately 100 ppm.
Claim 53
Dependent Claim
22 words
The method of claim 48 , wherein NOx is produced below approximately 2 ppm and CO is produced below approximately 10 ppm.
Claim 54
Dependent Claim
33 words
The method of claim 38 , wherein the controlling includes monitoring at least one characteristic of at least one of the fuel-air mixture and the hot combustion gas to control the residence time.
Claim 55
Dependent Claim
39 words
The method of claim 50 , wherein the monitoring includes sensing at least one of fuel amount, air flow rate, fuel feed rate, fuel-air mixture temperature, hot combustion gas temperature, the production of NOx, and the production of CO.
Claim 56
Dependent Claim
38 words
The method of claim 38 , wherein the production of NOx and the production of CO are monitored, and the residence time is controlled to reduce NOx below a preselected level while maintaining CO below a preselected level.
Claim 57
Dependent Claim
103 words
The method of claim 38 , wherein the combustor includes a preburner upstream of the catalyst, and the temperature of at least one of the fuel-air mixture and the catalyst outlet gas is controlled by at least one of: adjusting the fraction of air bypassing the catalyst, adjusting the fuel supplied to the combustor by proportioning the fuel supplied between the catalyst and the preburner, adjusting air input to the preburner, adjusting the composition of the fuel by introduction of components that affect the ignition delay time, and introducing water in at least one of upstream of the combustor and in the combustor.
Claim 58
Dependent Claim
52 words
The method of claim 53 , wherein the temperature of the hot combustion gas is maintained in a predetermined range for energy extraction and the fuel supplied the preburner is controlled to move the homogenous combustion wave to a location to reduce NOx production while maintaining CO production below about 50 ppm.
Claim 59
Dependent Claim
62 words
The method of claim 38 , wherein the controlling includes utilizing an empirical model of the operation of the combustor under a range of operating parameters, calculating the residence time of the hot combustion gases in the combustor as the parameters change, and setting system operating controls to selectively position the location of the homogeneous wave to achieve a desired residence time.
References Cited (Backward Citations)
US3928961A
Cited
US3975900A
Cited
US4197701A
Cited
US4534165A
Cited
US4473536A
Cited
US4731989A
Cited
US4726181A
Cited
US4966001A
Cited
US5133180A
Cited
US5161366A
Cited
US5263998A
Cited
US5139755A
Cited
US5281128A
Cited
US5183401A
Cited
US5425632A
Cited
US5248251A
Cited
US5250489A
Cited
US5259754A
Cited
US5232357A
Cited
US5511972A
Cited
US5461855A
Cited
US5634784A
Cited
US5235804A
Cited
US5165224A
Cited
US5318436A
Cited
US5263325A
Cited
US5269679A
Cited
US5413477A
Cited
US5551239A
Cited
US5879148A
Cited
US5554021A
Cited
US5581997A
Cited
US5461864A
Cited
US5452574A
Cited
US5518697A
Cited
US5512250A
Cited
US5569020A
Cited
US5551869A
Cited
US6116014A
Cited
US6094916A
Cited
US5826429A
Cited
US6201029B1
Cited
US6000212A
Cited
US6289667B1
Cited
US6105360A
Cited
US5965001A
Cited
US6109018A
Cited
US6286482B1
Cited
US5957682A
Cited
US5985222A
Cited
US6066303A
Cited
US5937632A
Cited
US5896738A
Cited
US5937634A
Cited
US5913675A
Cited
US6122916A
Cited
US6226977B1
Cited
US6217832B1
Cited
US6237343B1
Cited
US6038861A
Cited
US6082111A
Cited
US6089855A
Cited
US6095793A
Cited
US6298654B1
Cited
US20010046650A1
Cited
US6280695B1
Cited
US6250877B1
Cited
WO2002068867A2
Cited
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