CA1212617A - Staged fuel and air for low nox burner - Google Patents
Staged fuel and air for low nox burnerInfo
- Publication number
- CA1212617A CA1212617A CA000412055A CA412055A CA1212617A CA 1212617 A CA1212617 A CA 1212617A CA 000412055 A CA000412055 A CA 000412055A CA 412055 A CA412055 A CA 412055A CA 1212617 A CA1212617 A CA 1212617A
- Authority
- CA
- Canada
- Prior art keywords
- fuel
- burner
- air
- total
- reaction zone
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/20—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone
- F23D14/22—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone with separate air and gas feed ducts, e.g. with ducts running parallel or crossing each other
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C6/00—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion
- F23C6/04—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in series connection
- F23C6/045—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in series connection with staged combustion in a single enclosure
- F23C6/047—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in series connection with staged combustion in a single enclosure with fuel supply in stages
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C2201/00—Staged combustion
- F23C2201/20—Burner staging
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C2201/00—Staged combustion
- F23C2201/30—Staged fuel supply
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
Abstract
ABSTRACT OF THE INVENTION
A low NOx burner for a furnace and a method of operating the burner involving a primary and secondary combustion zone wherein staged fuel and air to both combustion zones is provided. By injection of from about 40 to 60%
of the liquid or gaseous hydrocarbon fuel along with about 90% of the total air required to a first reaction zone and injection of the remaining fuel with the remaining 10% of the air to a secondary reaction zone the formation of NOx is significantly suppressed. Such a burner is useful in minimizing NOx emissions for a variety of furnace types including both natural draft and forced draft furnaces.
A low NOx burner for a furnace and a method of operating the burner involving a primary and secondary combustion zone wherein staged fuel and air to both combustion zones is provided. By injection of from about 40 to 60%
of the liquid or gaseous hydrocarbon fuel along with about 90% of the total air required to a first reaction zone and injection of the remaining fuel with the remaining 10% of the air to a secondary reaction zone the formation of NOx is significantly suppressed. Such a burner is useful in minimizing NOx emissions for a variety of furnace types including both natural draft and forced draft furnaces.
Description
~Z~2~i~7 This invention relates to a method and apparatus for burning :~uel resul~ing in low NOX forma~ion. More specifically, this invention relates to a staged fuel and air injection burner.
With the advent of contemporary environmental e~ission standards being imposed by various governmental authorities and agencies involving ever stricter regulations, methods and apparatus to suppress the formation of oxides of nitrogen during combustion with air are becoming increasingly numerous.
Various techniques have been suggested and employed in the design and operation of burners and furnaces to meet these regulations. Thus it is known that to burn a hydrocarbon fuel in less than a stoichiometric concentration of oxygen intentionally produces a reducing environment of CO and H2. This concept is utilized in a staged air type low NOX burner wherein the fuel is first burned in a deficiency of air in one zone producing a reduced en~ironment that suppresses N0x formation and then the remaining portion of the air is added in a subsequent zone. Staged fuel has also been suggested wherein all of the air and some of the fuel is burned in the first zone and then the remaining fuel is added in the second zone. The presence of an over-abundance of air in the first reaction zone acts as a diluent, thus lowering the temperature and supprcssing formation of NOX. It has also been proposed to recirculate flue gas to accomplish the lowering of the flame temperature.
However, each of the prior art processes has certain inherent de ficiencies and associated problems which have led to limited commercial acceptance. For exc~mple, when burning fuel in a substoichiometric o~ygen environment the tendency for soot formation is increased. The presence of even small amounts of soot will alter the heat transfer properties of the furnace and heat exchanger surfaces downstream from the burner. Also, flame . -- 1 --~p~ ~
stability can become a critical factor when operatiny a burner a-t significantly substoichiome-tric conditions.
In view of the problems associated with previously proposed low NOX burners, the present invention provides a low NOX emission fuel-air burner for a furance charnber comprising: an air-fuel mixing and injection burner attached to the wall of said furnace such that the downstream face of said burner terminates substantially adjacent an inner wall of said furance chamber;
means to supply to said burner, at a given ins-tant of burning, a given total amount of fuel under pressure and a given total amount of air~ said total amount of air being at least substantially stoichiometrically sufficient to burn said total amount of fuel supplied to said burner; means to create a primary reaction burning zone that begins in an enclosed space upstream of said inner wall and extends downstream of said inner wall into said furnace chamber and means to supply to said burning zone a first portion of said total fuel and a por-tion of said total air whlch exceeds the stoichiometric requi~ements for burning said first portion of fuel thereto; a plurality of conduits in said burner ]ocated adjacent said enclosed space, said conduits providing communication be-tween said total air supply and said furnace chamber; fuel injection nozzle means positioned within each of said conduits such that there is passage of said a-ir thereabou-t said nozzle means terminating adjacent said downstream face of said burner; means to supply the remaining portion of said total fuel to said nozzle means, and means to supply the remaining portion of said total air through said conduits surrounding said nozzle means, said remaining portion of sald total air being less ~2~7 than the stoichiometric requirements to burn said remaining portion of said total fuel; said nozzle rneans directing said remaininy portion of said total fuel as a fan shaped sheet which along with said remaining portion of said total air contributes to the formation of an unconfined secondary reaction burning zone sub-stantially surrounding and reacting with a substantial portion of the unconfined effluent of said primary reaction zone within said furnace chamber, and to cause the inspira-tion of products of com--bustion that substantially surround said secondary reaction zone into said secondary reaction zone.
The present invention preferably provides for the fuel to be proportioned from about 40 to 60% to the primary reaction zone and then from about 60 to 40% to the second reaction zone while the air is proportioned from about 80 to 95% to the primary zone (preferably 90%~ and from about 20 t 5% to the secondary zone (preferably 10%).
It is an object of the present invention to provide a method and apparatus for burning a hydrocarbon fuel resulting in reduced emission of nitrogen oxides generated by the combustion.
It is a further object that a two stage fuel and air system be employed in a manner that maintains furnace ef~iciency without significant soot forma-tion. And, it is an additiorlal object that the method and apparatus be consistent with a variety of burner designs including, for e~ampler flat flame design, round or conical flame burners, high intensity burners and the like. Ful-fillment of these objects and the presence and fulfillment of other objects will be apparent upon complete reading of the specification and claims taken in conjunction with the attached drawings, in ~2~
which:
Figure 1 is a cross-sectional view of one embodirnent of the invention illustrating a T-bar primary nozzle and a pair of secondary nozzles;
Fi~ure 2 is a cross-sectional side view of the T-bar primary nozzle of Figure l;
Figure 3 is an end view of the burner of Figure l;
Figure 4 illustrates the orifice configuration of the secondary nozzle for the burner illustrated in Figure l;
Figure 5 is a cross-sectional view of an alternate embodi-ment of this invention illustrating a domed nozzle;
- 3a -~2~2¢~
Figures 6, 7 and 8 illustrate an alternate secondary nozzle and orifice configuration for burner of Figure 5; and Figure 9 is another embodiment illustrating a pair of flat flame design primary nozzles.
Referring now to the drawing and, in particular, to Figures 1, 2 and 3 there is shown one embodiment of the present invention wherein the burner is indicated generally by the numeral 10. This particular embodiment involves a primary burner tube 12 leading to a T-bar primary nozzle 14 along with a pair of secondary burner tubes 16 and secondary burner nozzles 18 all being supplied hydrocarbon fuel from a common source through tube 20. The fuel exiting primary nozzle 14 enters the primary combustion zone 22 wherein it is burned in the presence of a significant stoichiometric excess of air flowing through the interior 24 of the burner and entering the primary reaction zone 22 through an annular space 26 surrounding the primary nozzle 14, as indicated by the presence of arrows.
The effluent from the primary reaction zone 22 enters a larger secondary reaction zone 2S. Simultaneously, the fuel exiting the secondary nozzl~ 18 is mixed with air from the interior 24 of the burner 10 passing througll annular conduits 30 surrounding burner tubes 16 and is then burned in the secondary reaction zone 28 in the presence of the effluent from the first reaction zone 22.
The orifices of the respective T-bar nozzle 14 and secondary nozzles 18 are sized such that the fuel is proportioned between the primary reaction zone and the secondary reaction zone. Preferably from about 40 to about 60%
of the fuel is directed through the primary nozzle 14 and the remaining fuel is directed to the secondary nozzles 18. Similarly, the cross-sectional area - ~,2~Z~q of the annular space 26 and the annular conduits 30 for conducting air to primary and secondary reaction zones are selected such as to deliver about 80 to 95% of the total air to the primary reaction zone 22 and the remaining 20 to 5% of the total air to the secondary reaction zone 28.
Figure 4 illustrates the directional characteristics of the orifices of each secondary nozzle 18. As illustrated, the five fuel ports 32 will issue a fan like sheet of fuel directed towards the effluent of the primary combus-tion zone.
In Figure 5 an alternate forced draft burner 10 is illustrated involving a single gas nozzle 34 that directs the fuel delivered through con-duit 36 into the primary combustion zone 38 defined by the refractory walls 40 of the burner. Riser pipes 42 fitted with orifice tips 44 extend through this refr~ctory wall 40 such as to deliver the secondary fuel to the secondary combustion zone 46. Similar to Figure 1, combustion air flows through the interior 48 of burner 10 into the primary zone 38 by way of annular conduit 49 and into secondary combustion zone 46 through annular openings 50.
~igures 6, 7 and 8 illustrate the basic orifice or port configuration 52 of the secondary nozzles 44 including alternate angles oE inclination ~see Figure 7~ towards the axial direction oE the Elow in the primary reaction zone 38.
Figure 9 illustrates another alternate embodiment of a staged fuel and air burner 10 of the present invention wherein the particular burner is a flat flame design involving a pair of primary nozzles 54 and 56 each essen-tially adjacent to the refractory walls forming the primary reaction zone 58.
Similar to the previous embodiments, secondary fuel conduits 60 and 62 pass throug}l the refractory material such as to deliver fuel to the secondary reaction zone 64.
~2~21~
EXAMPLE
In order to evaluate the principle of separating the gaseous fuel into two essentially equal but sequential burning stages wherein a significant stoichiometric excess or major portion of the air is employed in the first stage with the remaining minor portion of the air in the second stage, a series of tests were conducted using a burner configuration as illustrated in Figure 5. The burner was of a forced draft design using natural gas. A
center mounted gas gun was mounted to fire inside a refractory chamber. Four riser pipes fitted with orifice tips were installed through the refractory wall of the combustion chamber parallel to the center line o the burner.
Three sets of tips were tested, each having orifices discharging at different angles to the tip centerline. The burner was tested by firing vertically upward into a furnace.
Three series of tests were conducted. One series for each set of secondary riser tip drillings. The tip drillings included three orifices, and were oriented in the first series discharging vertically upward (parallel to the centerline of the burner), in the second series discharging at a small angle, e.g. 15 off vertical (towards the burner centerline) and in the third series discharging 30 off vertical ~towards the burner ccn~erline~. Each test series of each set of tips included variations of primary1secondary fuel ratio and turned down tests.
Figure 10 illustrates the NO levels achieved for each set of tips at various fuel split ratios. The burner was also fired on center gas only to establish the base point for non-staged operation of 80 ppm NOX. The lowest NOX levels were obtained with secondary orifices discharging parallel to the burner axis, but this set of tips also produces the highest level of combus-~2~2~
tibles. Turn down on 30 tips was about 3:1 on a fifty/fifty fuel split, and turn down on 15 tips was about 2:1 on a forty/sixty split. Flame appearance was generally good on all arrangements.
From the data and test results it is readily apparent that the basic concept of staged air and fuel combustion is capable of producing NO
le~els significantly lower than conventional combustion. The test results have also established that these low NO levels are achieved in the absence of significant soot formation or flame instability. Additional advantages of the present invention include the fact that the NOx levels achieved are lower than those associated with staged air combustion and the fact that the basic concept of staged air and fuel is compatible with a wide variety of ~ypes of burners.
With the advent of contemporary environmental e~ission standards being imposed by various governmental authorities and agencies involving ever stricter regulations, methods and apparatus to suppress the formation of oxides of nitrogen during combustion with air are becoming increasingly numerous.
Various techniques have been suggested and employed in the design and operation of burners and furnaces to meet these regulations. Thus it is known that to burn a hydrocarbon fuel in less than a stoichiometric concentration of oxygen intentionally produces a reducing environment of CO and H2. This concept is utilized in a staged air type low NOX burner wherein the fuel is first burned in a deficiency of air in one zone producing a reduced en~ironment that suppresses N0x formation and then the remaining portion of the air is added in a subsequent zone. Staged fuel has also been suggested wherein all of the air and some of the fuel is burned in the first zone and then the remaining fuel is added in the second zone. The presence of an over-abundance of air in the first reaction zone acts as a diluent, thus lowering the temperature and supprcssing formation of NOX. It has also been proposed to recirculate flue gas to accomplish the lowering of the flame temperature.
However, each of the prior art processes has certain inherent de ficiencies and associated problems which have led to limited commercial acceptance. For exc~mple, when burning fuel in a substoichiometric o~ygen environment the tendency for soot formation is increased. The presence of even small amounts of soot will alter the heat transfer properties of the furnace and heat exchanger surfaces downstream from the burner. Also, flame . -- 1 --~p~ ~
stability can become a critical factor when operatiny a burner a-t significantly substoichiome-tric conditions.
In view of the problems associated with previously proposed low NOX burners, the present invention provides a low NOX emission fuel-air burner for a furance charnber comprising: an air-fuel mixing and injection burner attached to the wall of said furnace such that the downstream face of said burner terminates substantially adjacent an inner wall of said furance chamber;
means to supply to said burner, at a given ins-tant of burning, a given total amount of fuel under pressure and a given total amount of air~ said total amount of air being at least substantially stoichiometrically sufficient to burn said total amount of fuel supplied to said burner; means to create a primary reaction burning zone that begins in an enclosed space upstream of said inner wall and extends downstream of said inner wall into said furnace chamber and means to supply to said burning zone a first portion of said total fuel and a por-tion of said total air whlch exceeds the stoichiometric requi~ements for burning said first portion of fuel thereto; a plurality of conduits in said burner ]ocated adjacent said enclosed space, said conduits providing communication be-tween said total air supply and said furnace chamber; fuel injection nozzle means positioned within each of said conduits such that there is passage of said a-ir thereabou-t said nozzle means terminating adjacent said downstream face of said burner; means to supply the remaining portion of said total fuel to said nozzle means, and means to supply the remaining portion of said total air through said conduits surrounding said nozzle means, said remaining portion of sald total air being less ~2~7 than the stoichiometric requirements to burn said remaining portion of said total fuel; said nozzle rneans directing said remaininy portion of said total fuel as a fan shaped sheet which along with said remaining portion of said total air contributes to the formation of an unconfined secondary reaction burning zone sub-stantially surrounding and reacting with a substantial portion of the unconfined effluent of said primary reaction zone within said furnace chamber, and to cause the inspira-tion of products of com--bustion that substantially surround said secondary reaction zone into said secondary reaction zone.
The present invention preferably provides for the fuel to be proportioned from about 40 to 60% to the primary reaction zone and then from about 60 to 40% to the second reaction zone while the air is proportioned from about 80 to 95% to the primary zone (preferably 90%~ and from about 20 t 5% to the secondary zone (preferably 10%).
It is an object of the present invention to provide a method and apparatus for burning a hydrocarbon fuel resulting in reduced emission of nitrogen oxides generated by the combustion.
It is a further object that a two stage fuel and air system be employed in a manner that maintains furnace ef~iciency without significant soot forma-tion. And, it is an additiorlal object that the method and apparatus be consistent with a variety of burner designs including, for e~ampler flat flame design, round or conical flame burners, high intensity burners and the like. Ful-fillment of these objects and the presence and fulfillment of other objects will be apparent upon complete reading of the specification and claims taken in conjunction with the attached drawings, in ~2~
which:
Figure 1 is a cross-sectional view of one embodirnent of the invention illustrating a T-bar primary nozzle and a pair of secondary nozzles;
Fi~ure 2 is a cross-sectional side view of the T-bar primary nozzle of Figure l;
Figure 3 is an end view of the burner of Figure l;
Figure 4 illustrates the orifice configuration of the secondary nozzle for the burner illustrated in Figure l;
Figure 5 is a cross-sectional view of an alternate embodi-ment of this invention illustrating a domed nozzle;
- 3a -~2~2¢~
Figures 6, 7 and 8 illustrate an alternate secondary nozzle and orifice configuration for burner of Figure 5; and Figure 9 is another embodiment illustrating a pair of flat flame design primary nozzles.
Referring now to the drawing and, in particular, to Figures 1, 2 and 3 there is shown one embodiment of the present invention wherein the burner is indicated generally by the numeral 10. This particular embodiment involves a primary burner tube 12 leading to a T-bar primary nozzle 14 along with a pair of secondary burner tubes 16 and secondary burner nozzles 18 all being supplied hydrocarbon fuel from a common source through tube 20. The fuel exiting primary nozzle 14 enters the primary combustion zone 22 wherein it is burned in the presence of a significant stoichiometric excess of air flowing through the interior 24 of the burner and entering the primary reaction zone 22 through an annular space 26 surrounding the primary nozzle 14, as indicated by the presence of arrows.
The effluent from the primary reaction zone 22 enters a larger secondary reaction zone 2S. Simultaneously, the fuel exiting the secondary nozzl~ 18 is mixed with air from the interior 24 of the burner 10 passing througll annular conduits 30 surrounding burner tubes 16 and is then burned in the secondary reaction zone 28 in the presence of the effluent from the first reaction zone 22.
The orifices of the respective T-bar nozzle 14 and secondary nozzles 18 are sized such that the fuel is proportioned between the primary reaction zone and the secondary reaction zone. Preferably from about 40 to about 60%
of the fuel is directed through the primary nozzle 14 and the remaining fuel is directed to the secondary nozzles 18. Similarly, the cross-sectional area - ~,2~Z~q of the annular space 26 and the annular conduits 30 for conducting air to primary and secondary reaction zones are selected such as to deliver about 80 to 95% of the total air to the primary reaction zone 22 and the remaining 20 to 5% of the total air to the secondary reaction zone 28.
Figure 4 illustrates the directional characteristics of the orifices of each secondary nozzle 18. As illustrated, the five fuel ports 32 will issue a fan like sheet of fuel directed towards the effluent of the primary combus-tion zone.
In Figure 5 an alternate forced draft burner 10 is illustrated involving a single gas nozzle 34 that directs the fuel delivered through con-duit 36 into the primary combustion zone 38 defined by the refractory walls 40 of the burner. Riser pipes 42 fitted with orifice tips 44 extend through this refr~ctory wall 40 such as to deliver the secondary fuel to the secondary combustion zone 46. Similar to Figure 1, combustion air flows through the interior 48 of burner 10 into the primary zone 38 by way of annular conduit 49 and into secondary combustion zone 46 through annular openings 50.
~igures 6, 7 and 8 illustrate the basic orifice or port configuration 52 of the secondary nozzles 44 including alternate angles oE inclination ~see Figure 7~ towards the axial direction oE the Elow in the primary reaction zone 38.
Figure 9 illustrates another alternate embodiment of a staged fuel and air burner 10 of the present invention wherein the particular burner is a flat flame design involving a pair of primary nozzles 54 and 56 each essen-tially adjacent to the refractory walls forming the primary reaction zone 58.
Similar to the previous embodiments, secondary fuel conduits 60 and 62 pass throug}l the refractory material such as to deliver fuel to the secondary reaction zone 64.
~2~21~
EXAMPLE
In order to evaluate the principle of separating the gaseous fuel into two essentially equal but sequential burning stages wherein a significant stoichiometric excess or major portion of the air is employed in the first stage with the remaining minor portion of the air in the second stage, a series of tests were conducted using a burner configuration as illustrated in Figure 5. The burner was of a forced draft design using natural gas. A
center mounted gas gun was mounted to fire inside a refractory chamber. Four riser pipes fitted with orifice tips were installed through the refractory wall of the combustion chamber parallel to the center line o the burner.
Three sets of tips were tested, each having orifices discharging at different angles to the tip centerline. The burner was tested by firing vertically upward into a furnace.
Three series of tests were conducted. One series for each set of secondary riser tip drillings. The tip drillings included three orifices, and were oriented in the first series discharging vertically upward (parallel to the centerline of the burner), in the second series discharging at a small angle, e.g. 15 off vertical (towards the burner centerline) and in the third series discharging 30 off vertical ~towards the burner ccn~erline~. Each test series of each set of tips included variations of primary1secondary fuel ratio and turned down tests.
Figure 10 illustrates the NO levels achieved for each set of tips at various fuel split ratios. The burner was also fired on center gas only to establish the base point for non-staged operation of 80 ppm NOX. The lowest NOX levels were obtained with secondary orifices discharging parallel to the burner axis, but this set of tips also produces the highest level of combus-~2~2~
tibles. Turn down on 30 tips was about 3:1 on a fifty/fifty fuel split, and turn down on 15 tips was about 2:1 on a forty/sixty split. Flame appearance was generally good on all arrangements.
From the data and test results it is readily apparent that the basic concept of staged air and fuel combustion is capable of producing NO
le~els significantly lower than conventional combustion. The test results have also established that these low NO levels are achieved in the absence of significant soot formation or flame instability. Additional advantages of the present invention include the fact that the NOx levels achieved are lower than those associated with staged air combustion and the fact that the basic concept of staged air and fuel is compatible with a wide variety of ~ypes of burners.
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A low NOx emission fuel-air burner for a furance chamber comprising:
an air-fuel mixing and injection burner attached to the wall of said furnace such that the downstream face of said burner terminates substantially adjacent an inner wall of said furnace chamber;
means to supply to said burner, at a given instant of burning, a given total amount of fuel under pressure and a given total amount of air, said total amount of air being at least substantially stoichiometrically sufficient to burn said total amount of fuel supplied to said burner;
means to create a primary reaction burning zone that begins in an enclosed space upstream of said inner wall and extends downstream of said inner wall into said furnace chamber and means to supply to said burning zone a first portion of said total fuel and a portion of said total air which exceeds the stoichiometric requirements for burning said first portion of fuel thereto;
a plurality of conduits in said burner located adjacent said enclosed space, said conduits providing communication between said total air supply and said furnace chamber;
fuel injection nozzle means positioned within each of said conduits such that there is passage of said air thereabout, said nozzle means terminating adjacent said downstream face of said burner;
means to supply the remaining portion of said total fuel to said nozzle means, and means to supply the remaining portion of said total air through said conduits surrounding said nozzle means said remaining portion of said total air being less than the stoichiometric requirements to burn said remaining portion of said total fuel;
said nozzle means directing said remaining portion of said total fuel as a fan shaped sheet which along with said remaining portion of said total air contributes to the formation of an unconfined secondary reaction burning zone substantially surround-ing and reacting with a substantial portion of the unconfined effluent of said primary reaction zone within said furnace chamber, and to cause the inspiration of products of combustion that substantially surround said secondary reaction zone into said secondary reaction zone.
an air-fuel mixing and injection burner attached to the wall of said furnace such that the downstream face of said burner terminates substantially adjacent an inner wall of said furnace chamber;
means to supply to said burner, at a given instant of burning, a given total amount of fuel under pressure and a given total amount of air, said total amount of air being at least substantially stoichiometrically sufficient to burn said total amount of fuel supplied to said burner;
means to create a primary reaction burning zone that begins in an enclosed space upstream of said inner wall and extends downstream of said inner wall into said furnace chamber and means to supply to said burning zone a first portion of said total fuel and a portion of said total air which exceeds the stoichiometric requirements for burning said first portion of fuel thereto;
a plurality of conduits in said burner located adjacent said enclosed space, said conduits providing communication between said total air supply and said furnace chamber;
fuel injection nozzle means positioned within each of said conduits such that there is passage of said air thereabout, said nozzle means terminating adjacent said downstream face of said burner;
means to supply the remaining portion of said total fuel to said nozzle means, and means to supply the remaining portion of said total air through said conduits surrounding said nozzle means said remaining portion of said total air being less than the stoichiometric requirements to burn said remaining portion of said total fuel;
said nozzle means directing said remaining portion of said total fuel as a fan shaped sheet which along with said remaining portion of said total air contributes to the formation of an unconfined secondary reaction burning zone substantially surround-ing and reacting with a substantial portion of the unconfined effluent of said primary reaction zone within said furnace chamber, and to cause the inspiration of products of combustion that substantially surround said secondary reaction zone into said secondary reaction zone.
2. A burner of claim 1 including means to supply within the range of about 40 to about 60% of said total fuel to said primary reaction zone and about 60 to about 40% of said fuel being supplied to said secondary reaction zone.
3. A burner of claim 2 including means to supply in the range from about 80 to 95% of the said total air to said primary reaction zone.
4. A burner of claim 1 including means to supply in the range from about 80 to about 95% of the said total air to said primary reaction zone.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US30641281A | 1981-09-28 | 1981-09-28 | |
| US306,412 | 1981-09-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1212617A true CA1212617A (en) | 1986-10-14 |
Family
ID=23185184
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000412055A Expired CA1212617A (en) | 1981-09-28 | 1982-09-23 | Staged fuel and air for low nox burner |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0076036B1 (en) |
| JP (1) | JPS5875606A (en) |
| CA (1) | CA1212617A (en) |
| DE (1) | DE3276191D1 (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3331989A1 (en) * | 1983-09-05 | 1985-04-04 | L. & C. Steinmüller GmbH, 5270 Gummersbach | METHOD FOR REDUCING NO (DOWN ARROW) X (DOWN ARROW) EMISSIONS FROM THE COMBUSTION OF NITROGENOUS FUELS |
| FR2625295B1 (en) * | 1987-12-24 | 1990-04-13 | Gaz De France | METHOD AND APPARATUS FOR PROVIDING THE STAGE COMBUSTION OF A FUEL-FUEL MIXTURE REDUCING THE PRODUCTION OF NITROGEN OXIDES |
| DK6789A (en) * | 1988-03-16 | 1989-09-17 | Bloom Eng Co Inc | PROCEDURE AND APPARATUS FOR COMPRESSING NO CREATION IN REGENERATIVE BURNERS. |
| GB8807859D0 (en) * | 1988-04-05 | 1988-05-05 | Nordsea Gas Technology Ltd | Combination burners |
| GB8824575D0 (en) * | 1988-10-20 | 1988-11-23 | Airoil Flaregas Ltd | Improvements in burner assemblies |
| NL8902963A (en) * | 1989-12-01 | 1991-07-01 | Int Flame Research Foundation | PROCESS FOR BURNING FUEL OF LOW NOX CONTENT IN THE COMBUSTION GASES USING THROUGH STAGE FUEL SUPPLY AND BURNER. |
| WO1992016792A1 (en) * | 1991-03-15 | 1992-10-01 | Radian Corporation | Apparatus and method for combustion within porous matrix elements |
| US5201650A (en) * | 1992-04-09 | 1993-04-13 | Shell Oil Company | Premixed/high-velocity fuel jet low no burner |
| JP2638394B2 (en) * | 1992-06-05 | 1997-08-06 | 日本ファーネス工業株式会社 | Low NOx combustion method |
| US5441404A (en) * | 1993-01-29 | 1995-08-15 | Gordan-Piatt Energy Group, Inc. | Burner assembly for reducing nitrogen oxides during combustion of gaseous fuels |
| US5944503A (en) * | 1998-05-20 | 1999-08-31 | Selas Corporation Of America | Low NOx floor burner, and heating method |
| US6685463B2 (en) * | 1999-12-16 | 2004-02-03 | Bloom Engineering Co., Inc. | Air and fuel staged burner |
| SE531957C2 (en) * | 2006-06-09 | 2009-09-15 | Aga Ab | Method for launching oxygen in an industrial furnace with conventional burner |
| RU2534189C2 (en) * | 2010-02-16 | 2014-11-27 | Дженерал Электрик Компани | Gas turbine combustion chamber (versions) and method of its operation |
| EP3078910B1 (en) * | 2015-04-08 | 2020-02-12 | Vysoké Ucení Technické V Brne | Gas burner with staged combustion |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1229229B (en) * | 1963-07-18 | 1966-11-24 | Zink Co John | Gaseous and liquid fuel burners |
| US4004875A (en) * | 1975-01-23 | 1977-01-25 | John Zink Company | Low nox burner |
| US4347052A (en) * | 1978-06-19 | 1982-08-31 | John Zink Company | Low NOX burner |
| US4257763A (en) * | 1978-06-19 | 1981-03-24 | John Zink Company | Low NOx burner |
| US4245980A (en) * | 1978-06-19 | 1981-01-20 | John Zink Company | Burner for reduced NOx emission and control of flame spread and length |
-
1982
- 1982-08-26 DE DE8282304508T patent/DE3276191D1/en not_active Expired
- 1982-08-26 EP EP82304508A patent/EP0076036B1/en not_active Expired
- 1982-09-23 CA CA000412055A patent/CA1212617A/en not_active Expired
- 1982-09-27 JP JP16824982A patent/JPS5875606A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5875606A (en) | 1983-05-07 |
| EP0076036A1 (en) | 1983-04-06 |
| EP0076036B1 (en) | 1987-04-29 |
| DE3276191D1 (en) | 1987-06-04 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |