US20080081301A1 - Low NOx combustion - Google Patents
Low NOx combustion Download PDFInfo
- Publication number
- US20080081301A1 US20080081301A1 US11/542,439 US54243906A US2008081301A1 US 20080081301 A1 US20080081301 A1 US 20080081301A1 US 54243906 A US54243906 A US 54243906A US 2008081301 A1 US2008081301 A1 US 2008081301A1
- Authority
- US
- United States
- Prior art keywords
- process chamber
- premix
- burner
- fuel
- oxidant
- 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.)
- Abandoned
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N1/00—Regulating fuel supply
- F23N1/02—Regulating fuel supply conjointly with air supply
- F23N1/022—Regulating fuel supply conjointly with air supply using electronic means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
-
- 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
- F23C2900/00—Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
- F23C2900/99001—Cold flame combustion or flameless oxidation processes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2225/00—Measuring
- F23N2225/08—Measuring temperature
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2227/00—Ignition or checking
- F23N2227/02—Starting or ignition cycles
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2237/00—Controlling
- F23N2237/02—Controlling two or more burners
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2237/00—Controlling
- F23N2237/20—Controlling one or more bypass conduits
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery
Definitions
- This technology relates to a method and apparatus for operating a furnace.
- a prior art furnace 10 has a wall structure 12 defining a process chamber 15 .
- the process chamber 15 is sized to contain a load to be heated.
- a burner 16 fires into the process chamber 15 .
- the burner 16 includes a mixer tube 18 and a burner tile 20 .
- the burner tile 20 defines a reaction zone 21 between the mixer tube 18 and the process chamber 15 .
- streams of fuel and oxidant form a combustible mixture known as premix as they flow together through the mixer tube 18 toward and into the reaction zone 21 through the open outer end 22 of the mixer tube 18 .
- An igniter 24 ignites the premix in the reaction zone 21 so that combustion proceeds with a flame that extends across the reaction zone 21 and through a port 25 that communicates with the process chamber 15 .
- a burner by definition, includes a flame stabilizer which functions to hold the flame in the desired location by inhibiting flashback and blow off.
- the premix flows from left to right as viewed in FIG. 1 , while the flame propagates in the opposite direction toward the source of premix. Flashback occurs when the flame advances too far into the mixer tube 18 . This can be inhibited by controlling the premix speed relative to the flame speed. Blow off occurs when the flame is driven too far from the mixer tube 18 .
- a flame stabilizer which, as known in the art, may comprise an obstruction that is placed in the premix flow path to slow the premix and thereby help to ensure that the premix speed does not overly exceed the flame speed.
- a flame stabilizer can further inhibit blow off by inducing turbulence that includes recirculation toward the stabilizer. The recirculating products of combustion help to anchor the flame by maintaining ignition of the premix near the stabilizer.
- the burner 16 includes a flame stabilizer 30 in the form of a circular metal plate.
- the plate 30 is preferably located coaxially within the mixer tube 18 at a location spaced a short distance inward from open outer end 22 , but could be located farther back inward from the end 22 or a short distance outward from the end 22 , as known in the art.
- the plate 30 extends fully across the inside of the mixer tube 18 , as shown in enlarged detail in FIG. 2 , but an alternative arrangement could provide an annular flow area radially between the plate 30 and the surrounding tube 18 . In either case, small ports 31 extend through the plate 20 to direct jets of premix into the reaction zone 21 .
- the jets of premix together induce recirculation toward the outer side surface 32 of the plate 30 , and also define zones of lower premix flow velocity in the spaces between the jets.
- the plate 30 thus functions to inhibit blow off by anchoring the flame at or near the surface 32 .
- the plate 30 also functions to inhibit flashback upstream of the plate 30 , which is to the left as viewed in FIGS. 1 and 2 , by enabling the upstream premix speed to exceed the flame speed as needed.
- the furnace 10 can be operated in a mode in which diffuse combustion occurs in the process chamber 15 in the absence of a flame in the reaction zone 21 . This can occur without the use of the igniter 24 if the premix is injected through the reaction zone 21 and into the process chamber 15 when the process chamber 15 is at or above the autoignition temperature of the premix.
- the diffuse combustion mode produces less NOx because the furnace gases circulating throughout the volume of the process chamber 15 absorb heat from the burning reactants. This results in a lower flame temperature which, in turn, results in less NOx formation.
- FIG. 3 Another prior art furnace 40 with a process chamber 43 and a burner 44 is shown partially in the schematic view of FIG. 3 .
- the burner 44 of FIG. 3 raises the process chamber 43 to the auto ignition temperature of the premix, and is then shut off.
- Diffuse combustion follows as separate streams of fuel and air are injected into the process chamber 43 through fuel and air injectors 46 and 48 , respectively.
- Combustion in the diffuse mode of FIG. 3 produces less NOx than combustion in the diffuse mode of FIG. 1 . This is because the reactants of FIG. 3 are injected directly into the process chamber 43 , whereas the reactants of FIG. 1 must first move through the reaction zone 21 before reaching the process chamber 15 . Direct injection into the process chamber 43 enables the reactants of FIG.
- the claimed invention provides an apparatus for use with a furnace process chamber and a burner.
- the burner which includes a flame stabilizer, is operative to fire into the process chamber with flame stabilization.
- the claimed invention comprises a premix injection apparatus configured to inject unignited premix into the process chamber without flame stabilization. In the absence of a stabilized flame at the premix injection apparatus, the furnace can operate with diffuse combustion more uniformly throughout the process chamber with correspondingly less NOx formation.
- FIG. 1 is a schematic view of parts of a prior art furnace.
- FIG. 2 is an enlarged partial view of parts of the furnace of FIG. 1 .
- FIG. 3 is a schematic view of parts of another prior art furnace.
- FIG. 4 is a schematic view of parts of a furnace configured according to the claimed invention.
- FIG. 5 is a schematic view of parts of another furnace configured according to the claimed invention.
- FIG. 6 is a schematic view of parts of yet another furnace configured according to the claimed invention.
- the furnaces illustrated schematically in FIGS. 4 , 5 and 6 have parts that are examples of the elements recited in the apparatus claims, and can be operated in steps that are examples of the elements recited in the method claims.
- the following description thus includes examples of how a person of ordinary skill in the art can make and use the claimed invention. It is presented here to provide enablement and best mode without imposing limitations that are not recited in the claims.
- the various parts as shown, described, and claimed, may be of either original or retrofitted installation as required to accomplish any particular implementation of the claimed invention.
- the furnace 100 of FIG. 4 includes a wall structure 110 .
- the wall structure 110 defines a process chamber 115 that is sized to contain a load to be heated.
- a burner 116 is mounted on the wall structure 110 and is operative to fire into the process chamber 115 .
- a reactant supply system 120 includes lines and valves that provide the burner 116 with fuel from a fuel source 122 , which is preferably a supply of natural gas, and with oxidant from an oxidant source 124 , which is preferably an air blower.
- the reactant supply system 120 also transmits fuel and oxidant from the sources 122 and 124 to a bypass apparatus 126 that delivers those reactants to the process chamber 115 separately from the burner 116 .
- a controller 130 operates the reactant supply system 120 to control combustion in the process chamber 115 .
- this burner 116 is a premix burner with a mixer tube 140 and a burner tile 142 .
- the burner tile 142 defines a reaction zone 145 between the mixer tube 140 and a port 147 leading to the process chamber 115 .
- the burner 116 also includes a flame stabilizer 148 .
- the flame stabilizer 148 could be configured in any suitable manner known in the art, but is preferably the same as the flame stabilizer 30 described above with reference to FIGS. 1 and 2 .
- the burner 116 includes a mixer body 160 that is coupled to the reactant supply system 120 .
- the mixer body 160 includes an oxidant coupling 162 , a fuel coupling 164 , and an internal fuel line 166 .
- the internal fuel line 166 extends from the fuel coupling 164 into the inner end of the mixer tube 140 .
- the oxidant coupling 162 communicates with the inner end of the mixer tube 140 through an oxidant plenum 165 within the mixer body 160 .
- the reactant supply system 120 has fuel and oxidant supply lines 170 and 172 . It also has a plurality of branch lines with flow control valves.
- a first branch line 174 extends from the fuel supply line 170 to the fuel coupling 164 at the burner 116 .
- a first valve 176 controls the flow of fuel through the first branch line 174 .
- a second branch line 178 extends from the oxidant supply line 172 to the oxidant coupling 162 at the burner 116 .
- a second valve 180 controls the flow of oxidant through the second branch line 178 .
- Third and fourth branch lines 184 and 186 likewise have third and fourth valves 188 and 190 . Those branch lines 184 and 186 extend from the fuel and oxidant supply lines 170 and 172 to the bypass apparatus 126 .
- the bypass apparatus 126 does not include a flame stabilizer. It is instead configured to inject unignited premix into the process chamber 115 without the influence of a flame stabilizer, whereby the resulting ignition and combustion of the premix proceeds without flame stabilization.
- the bypass apparatus 126 includes a mixer body 200 and a premix injector tube 204 .
- a mixing chamber 205 is defined within the mixer body 200 .
- the mixing chamber 205 communicates with the third branch line 184 through a fuel coupling 206 , and communicates with the fourth branch line 186 through an oxidant coupling 208 .
- the premix injector tube 204 has an open inner end 210 at the mixing chamber 205 and an open outer end 212 at the process chamber 115 .
- bypass apparatus 126 There is no structure in the bypass apparatus 126 for slowing the flow of premix at a location between the inner end 210 of the injector tube 204 and the region of the process chamber 115 where the premix emerges from the open outer end 112 of the injector tube 204 . Nor is there any structure for inducing upstream recirculation toward or within the injector tube 204 . Instead, the bypass apparatus 126 is free of any structure configured for the purpose of inhibiting flashback or blow off of a flame propagating in a direction inwardly of the premix injector tube 204 .
- the controller 130 has hardware and/or software configured to control combustion in the process chamber 115 by selective use of the burner 116 and the bypass apparatus 126 .
- the controller 130 may thus comprise any suitable programmable logic controller or other control device, or combination of control devices, that is programmed or otherwise configured to perform as recited in the claims. As the controller 130 carries out those instructions it actuates the valves 176 , 180 , 188 and 190 to initiate, regulate and terminate flows of reactant streams through the reactant supply system 120 .
- the controller 130 actuates an igniter 220 in the reaction zone 145 , and opens the first and second valves 176 and 180 while maintaining the third and fourth valves 188 and 190 in closed conditions.
- This transmits streams of fuel and oxidant to the mixer body 160 at the burner 116 while blocking transmission of fuel and oxidant to the process chamber 115 through the bypass apparatus 126 .
- the reactant streams transmitted to the burner 116 form premix as they mix and flow together through the mixer tube 140 toward the reaction zone 145 .
- the premix is ignited upon emerging form the mixer tube 140 to form a flame that projects through the reaction zone 145 and into the process chamber 115 through the port 147 under the influence of the flame stabilizing structure 148 .
- the flame sensor 222 may comprise any suitable device that is operative to detect the presence of a flame stabilized at a burner.
- suitable devices include, for example, a flame rod, a UV (ultraviolet) flame detector, an IR (infrared) flame detector, a thermopile, and an acoustic flame sensor.
- the controller 130 When a temperature sensor 224 indicates that the temperature in the process chamber 115 has risen to a level at or above the autoignition temperature of the premix, the controller 130 responds by shifting from the startup mode of operation to a diffuse combustion mode of operation.
- the controller 130 shifts to the diffuse combustion mode by closing the first and second valves 176 and 178 to block the transmission of fuel and oxidant to the burner 116 , and by opening the third and fourth valves 188 and 190 to transmit fuel and oxidant to the bypass apparatus 126 .
- the fuel and oxidant then mix together in the chamber 205 to form unignited premix that is transmitted through the injector tube 204 for injection into the process chamber 115 .
- the premix emerging from the open outer end 212 of the injector tube 204 flows into the process chamber 115 without the influence of a flame stabilizer. This enables autoignition of the premix to result in diffuse combustion more uniformly throughout the process chamber 115 . Since the bypass apparatus 126 does not produce a stabilized flame, the furnace 100 does not have a flame sensor in operative association with the bypass apparatus 126 , but instead employs the temperature sensor 224 as a safety device to monitor diffuse combustion in the process chamber 115 .
- the furnace 300 of FIG. 5 also is configured according to the claimed invention.
- a wall portion 302 of the furnace 300 defines a process chamber 305 .
- a premix burner 306 with an igniter 308 is operative to fire through a reaction zone 315 and into the process chamber 305 under the direction of a controller 320 . This is accomplished by actuating a reactant supply system 330 to transmit streams of fuel and oxidant from their sources 332 and 334 to a mixer tube 336 in the burner 306 in the manner described above with reference to the furnace 100 of FIG. 4 .
- the furnace 300 differs from the furnace 100 by including a bypass apparatus 340 that is structurally combined with the burner 306 rather than structurally separate from the burner 306 .
- the bypass apparatus 340 includes a premix injector tube 342 that extends through the burner tile 344 .
- the outer end 346 of the injector tube 342 is open to the process chamber 305 .
- the inner end 348 of the injector tube 342 is open to an oxidant plenum 349 within a bypass mixer body 350 that is joined with the mixer body 352 at the burner 306 .
- An oxidant branch line 360 with a flow control valve 362 extends from an oxidant supply line 364 to an oxidant coupling 366 at the bypass mixer body 350 .
- a fuel branch line 370 with a flow control valve 372 extends from a fuel supply line 374 to a fuel coupling 376 at the bypass mixer body 350 .
- the flow path of fuel from the source 332 to the injector tube 342 is completed by an internal fuel line 380 that extends from the fuel coupling 376 into the inner end 348 of the injector tube 342 .
- the controller 320 initiates a startup mode of operation by actuating the igniter 308 and opening the fuel and oxidant flow control valves 390 and 392 that serve the burner 306 .
- the resulting flame is stabilized by a flame stabilizer 394 and monitored by a flame sensor 396 throughout the startup mode.
- the flow control valves 362 and 372 that serve the bypass apparatus 340 are maintained in closed conditions throughout the startup mode.
- the controller 320 responds by shifting from the startup mode of operation to a diffuse combustion mode of operation. This is accomplished by closing the valves 390 and 392 that serve the burner 306 , and by opening the valves 362 and 372 that serve the burner bypass apparatus 340 . Streams of fuel and oxidant then flow into the open inner end 346 of the injector tube 342 and form premix as they flow together along the length of the tube 342 toward the process chamber 305 .
- the claimed invention further provides other operational modes in addition to the startup and diffuse combustion modes described above.
- furnace startup is not the only time at which the burner can be on while the bypass apparatus is off. That flame stabilization mode can be continued after startup, and can be alternated with the non-stabilization mode in which the burner is off and the bypass apparatus is on. It may also be appropriate to operate in a mode in which the burner and the bypass apparatus are on simultaneously. Overall target rates of fuel and oxidant injection could then be provided in partial rates at the burner and the bypass apparatus.
- FIG. 6 shows a modification of the furnace 300 in which fuel and oxidant valves are arranged to distribute the overall rates of fuel and oxidant injection between the burner mixer body 352 and the bypass mixer body 350 .
- a directional control valve 400 for fuel is shiftable to initiate, regulate, and terminate flows of fuel to only the burner mixer body 352 , to only the bypass mixer body 350 , or to both throughout a range of proportional conditions.
- a directional control valve 402 for oxidant is shiftable in the same manner.
Abstract
Description
- This technology relates to a method and apparatus for operating a furnace.
- As shown partially in the schematic view of
FIG. 1 , aprior art furnace 10 has awall structure 12 defining aprocess chamber 15. Theprocess chamber 15 is sized to contain a load to be heated. Aburner 16 fires into theprocess chamber 15. Theburner 16 includes amixer tube 18 and aburner tile 20. Theburner tile 20 defines areaction zone 21 between themixer tube 18 and theprocess chamber 15. - In operation of the
burner 16, streams of fuel and oxidant form a combustible mixture known as premix as they flow together through themixer tube 18 toward and into thereaction zone 21 through the openouter end 22 of themixer tube 18. Anigniter 24 ignites the premix in thereaction zone 21 so that combustion proceeds with a flame that extends across thereaction zone 21 and through aport 25 that communicates with theprocess chamber 15. - A burner, by definition, includes a flame stabilizer which functions to hold the flame in the desired location by inhibiting flashback and blow off. The premix flows from left to right as viewed in
FIG. 1 , while the flame propagates in the opposite direction toward the source of premix. Flashback occurs when the flame advances too far into themixer tube 18. This can be inhibited by controlling the premix speed relative to the flame speed. Blow off occurs when the flame is driven too far from themixer tube 18. This can be inhibited by a flame stabilizer which, as known in the art, may comprise an obstruction that is placed in the premix flow path to slow the premix and thereby help to ensure that the premix speed does not overly exceed the flame speed. A flame stabilizer can further inhibit blow off by inducing turbulence that includes recirculation toward the stabilizer. The recirculating products of combustion help to anchor the flame by maintaining ignition of the premix near the stabilizer. - In the example shown in
FIG. 1 , theburner 16 includes aflame stabilizer 30 in the form of a circular metal plate. Theplate 30 is preferably located coaxially within themixer tube 18 at a location spaced a short distance inward from openouter end 22, but could be located farther back inward from theend 22 or a short distance outward from theend 22, as known in the art. Theplate 30 extends fully across the inside of themixer tube 18, as shown in enlarged detail inFIG. 2 , but an alternative arrangement could provide an annular flow area radially between theplate 30 and the surroundingtube 18. In either case,small ports 31 extend through theplate 20 to direct jets of premix into thereaction zone 21. The jets of premix together induce recirculation toward theouter side surface 32 of theplate 30, and also define zones of lower premix flow velocity in the spaces between the jets. Theplate 30 thus functions to inhibit blow off by anchoring the flame at or near thesurface 32. Theplate 30 also functions to inhibit flashback upstream of theplate 30, which is to the left as viewed inFIGS. 1 and 2 , by enabling the upstream premix speed to exceed the flame speed as needed. - The
furnace 10 can be operated in a mode in which diffuse combustion occurs in theprocess chamber 15 in the absence of a flame in thereaction zone 21. This can occur without the use of theigniter 24 if the premix is injected through thereaction zone 21 and into theprocess chamber 15 when theprocess chamber 15 is at or above the autoignition temperature of the premix. The diffuse combustion mode produces less NOx because the furnace gases circulating throughout the volume of theprocess chamber 15 absorb heat from the burning reactants. This results in a lower flame temperature which, in turn, results in less NOx formation. - Another
prior art furnace 40 with aprocess chamber 43 and aburner 44 is shown partially in the schematic view ofFIG. 3 . Theburner 44 ofFIG. 3 raises theprocess chamber 43 to the auto ignition temperature of the premix, and is then shut off. Diffuse combustion follows as separate streams of fuel and air are injected into theprocess chamber 43 through fuel andair injectors FIG. 3 produces less NOx than combustion in the diffuse mode ofFIG. 1 . This is because the reactants ofFIG. 3 are injected directly into theprocess chamber 43, whereas the reactants ofFIG. 1 must first move through thereaction zone 21 before reaching theprocess chamber 15. Direct injection into theprocess chamber 43 enables the reactants ofFIG. 3 to become more extensively diluted by furnace gases as they mix together to form a combustible mixture prior to reaching the autoignition temperature. When the diluted reactants ignite, the greater amount of diluant absorbs more heat to suppress the flame temperature and thereby to suppress the formation of NOx. - The claimed invention provides an apparatus for use with a furnace process chamber and a burner. The burner, which includes a flame stabilizer, is operative to fire into the process chamber with flame stabilization. The claimed invention comprises a premix injection apparatus configured to inject unignited premix into the process chamber without flame stabilization. In the absence of a stabilized flame at the premix injection apparatus, the furnace can operate with diffuse combustion more uniformly throughout the process chamber with correspondingly less NOx formation.
-
FIG. 1 is a schematic view of parts of a prior art furnace. -
FIG. 2 is an enlarged partial view of parts of the furnace ofFIG. 1 . -
FIG. 3 is a schematic view of parts of another prior art furnace. -
FIG. 4 is a schematic view of parts of a furnace configured according to the claimed invention. -
FIG. 5 is a schematic view of parts of another furnace configured according to the claimed invention. -
FIG. 6 is a schematic view of parts of yet another furnace configured according to the claimed invention. - The furnaces illustrated schematically in
FIGS. 4 , 5 and 6 have parts that are examples of the elements recited in the apparatus claims, and can be operated in steps that are examples of the elements recited in the method claims. The following description thus includes examples of how a person of ordinary skill in the art can make and use the claimed invention. It is presented here to provide enablement and best mode without imposing limitations that are not recited in the claims. The various parts as shown, described, and claimed, may be of either original or retrofitted installation as required to accomplish any particular implementation of the claimed invention. - The
furnace 100 ofFIG. 4 includes awall structure 110. Thewall structure 110 defines aprocess chamber 115 that is sized to contain a load to be heated. Aburner 116 is mounted on thewall structure 110 and is operative to fire into theprocess chamber 115. Areactant supply system 120 includes lines and valves that provide theburner 116 with fuel from afuel source 122, which is preferably a supply of natural gas, and with oxidant from anoxidant source 124, which is preferably an air blower. Thereactant supply system 120 also transmits fuel and oxidant from thesources bypass apparatus 126 that delivers those reactants to theprocess chamber 115 separately from theburner 116. Acontroller 130 operates thereactant supply system 120 to control combustion in theprocess chamber 115. - Although a nozzle mix burner could be used, this
burner 116 is a premix burner with amixer tube 140 and aburner tile 142. Theburner tile 142 defines areaction zone 145 between themixer tube 140 and aport 147 leading to theprocess chamber 115. Theburner 116 also includes aflame stabilizer 148. Theflame stabilizer 148 could be configured in any suitable manner known in the art, but is preferably the same as theflame stabilizer 30 described above with reference toFIGS. 1 and 2 . - As further shown schematically in
FIG. 4 , theburner 116 includes amixer body 160 that is coupled to thereactant supply system 120. Themixer body 160 includes anoxidant coupling 162, afuel coupling 164, and aninternal fuel line 166. Theinternal fuel line 166 extends from thefuel coupling 164 into the inner end of themixer tube 140. Theoxidant coupling 162 communicates with the inner end of themixer tube 140 through anoxidant plenum 165 within themixer body 160. - The
reactant supply system 120 has fuel andoxidant supply lines first branch line 174 extends from thefuel supply line 170 to thefuel coupling 164 at theburner 116. Afirst valve 176 controls the flow of fuel through thefirst branch line 174. Asecond branch line 178 extends from theoxidant supply line 172 to theoxidant coupling 162 at theburner 116. Asecond valve 180 controls the flow of oxidant through thesecond branch line 178. Third andfourth branch lines fourth valves branch lines oxidant supply lines bypass apparatus 126. - Unlike the
burner 116, thebypass apparatus 126 does not include a flame stabilizer. It is instead configured to inject unignited premix into theprocess chamber 115 without the influence of a flame stabilizer, whereby the resulting ignition and combustion of the premix proceeds without flame stabilization. In this particular example, thebypass apparatus 126 includes amixer body 200 and apremix injector tube 204. A mixingchamber 205 is defined within themixer body 200. The mixingchamber 205 communicates with thethird branch line 184 through afuel coupling 206, and communicates with thefourth branch line 186 through anoxidant coupling 208. Thepremix injector tube 204 has an openinner end 210 at the mixingchamber 205 and an openouter end 212 at theprocess chamber 115. There is no structure in thebypass apparatus 126 for slowing the flow of premix at a location between theinner end 210 of theinjector tube 204 and the region of theprocess chamber 115 where the premix emerges from the open outer end 112 of theinjector tube 204. Nor is there any structure for inducing upstream recirculation toward or within theinjector tube 204. Instead, thebypass apparatus 126 is free of any structure configured for the purpose of inhibiting flashback or blow off of a flame propagating in a direction inwardly of thepremix injector tube 204. - The
controller 130 has hardware and/or software configured to control combustion in theprocess chamber 115 by selective use of theburner 116 and thebypass apparatus 126. Thecontroller 130 may thus comprise any suitable programmable logic controller or other control device, or combination of control devices, that is programmed or otherwise configured to perform as recited in the claims. As thecontroller 130 carries out those instructions it actuates thevalves reactant supply system 120. - In a startup mode of operation, the
controller 130 actuates anigniter 220 in thereaction zone 145, and opens the first andsecond valves fourth valves mixer body 160 at theburner 116 while blocking transmission of fuel and oxidant to theprocess chamber 115 through thebypass apparatus 126. The reactant streams transmitted to theburner 116 form premix as they mix and flow together through themixer tube 140 toward thereaction zone 145. The premix is ignited upon emerging form themixer tube 140 to form a flame that projects through thereaction zone 145 and into theprocess chamber 115 through theport 147 under the influence of theflame stabilizing structure 148. As a safety precaution the flame is monitored by thecontroller 130 and aflame sensor 222. Theflame sensor 222 may comprise any suitable device that is operative to detect the presence of a flame stabilized at a burner. Such devices that are known in the art include, for example, a flame rod, a UV (ultraviolet) flame detector, an IR (infrared) flame detector, a thermopile, and an acoustic flame sensor. - When a
temperature sensor 224 indicates that the temperature in theprocess chamber 115 has risen to a level at or above the autoignition temperature of the premix, thecontroller 130 responds by shifting from the startup mode of operation to a diffuse combustion mode of operation. Thecontroller 130 shifts to the diffuse combustion mode by closing the first andsecond valves burner 116, and by opening the third andfourth valves bypass apparatus 126. The fuel and oxidant then mix together in thechamber 205 to form unignited premix that is transmitted through theinjector tube 204 for injection into theprocess chamber 115. Importantly, the premix emerging from the openouter end 212 of theinjector tube 204 flows into theprocess chamber 115 without the influence of a flame stabilizer. This enables autoignition of the premix to result in diffuse combustion more uniformly throughout theprocess chamber 115. Since thebypass apparatus 126 does not produce a stabilized flame, thefurnace 100 does not have a flame sensor in operative association with thebypass apparatus 126, but instead employs thetemperature sensor 224 as a safety device to monitor diffuse combustion in theprocess chamber 115. - The
furnace 300 ofFIG. 5 also is configured according to the claimed invention. Awall portion 302 of thefurnace 300 defines aprocess chamber 305. Apremix burner 306 with anigniter 308 is operative to fire through areaction zone 315 and into theprocess chamber 305 under the direction of acontroller 320. This is accomplished by actuating areactant supply system 330 to transmit streams of fuel and oxidant from theirsources mixer tube 336 in theburner 306 in the manner described above with reference to thefurnace 100 ofFIG. 4 . - As shown in the drawing, the
furnace 300 differs from thefurnace 100 by including abypass apparatus 340 that is structurally combined with theburner 306 rather than structurally separate from theburner 306. Specifically, thebypass apparatus 340 includes apremix injector tube 342 that extends through theburner tile 344. Theouter end 346 of theinjector tube 342 is open to theprocess chamber 305. Theinner end 348 of theinjector tube 342 is open to anoxidant plenum 349 within abypass mixer body 350 that is joined with themixer body 352 at theburner 306. - An
oxidant branch line 360 with aflow control valve 362 extends from anoxidant supply line 364 to anoxidant coupling 366 at thebypass mixer body 350. Afuel branch line 370 with aflow control valve 372 extends from afuel supply line 374 to afuel coupling 376 at thebypass mixer body 350. The flow path of fuel from thesource 332 to theinjector tube 342 is completed by aninternal fuel line 380 that extends from thefuel coupling 376 into theinner end 348 of theinjector tube 342. - The
controller 320 initiates a startup mode of operation by actuating theigniter 308 and opening the fuel and oxidantflow control valves burner 306. The resulting flame is stabilized by aflame stabilizer 394 and monitored by aflame sensor 396 throughout the startup mode. Theflow control valves bypass apparatus 340 are maintained in closed conditions throughout the startup mode. - When the temperature in the
process chamber 305 reaches a level at or above the autoignition temperature of the premix, as indicated by atemperature sensor 398 in theprocess chamber 305, thecontroller 320 responds by shifting from the startup mode of operation to a diffuse combustion mode of operation. This is accomplished by closing thevalves burner 306, and by opening thevalves burner bypass apparatus 340. Streams of fuel and oxidant then flow into the openinner end 346 of theinjector tube 342 and form premix as they flow together along the length of thetube 342 toward theprocess chamber 305. - As shown in the drawing, there is no flame stabilizer in the premix flow path that extends through the
injector tube 342 and into theprocess chamber 305 from the openouter end 348 of theinjector tube 342. There is no flame sensor operatively associated with thebypass apparatus 340. Therefore, in operation of thebypass apparatus 340, an unignited stream of premix flows through the openouter end 348 of theinjector tube 342 and into theprocess chamber 305 without the influence of a flame stabilizer. Diffuse combustion in theprocess chamber 305 proceeds accordingly, and is monitored for safety by thetemperature sensor 398. - The claimed invention further provides other operational modes in addition to the startup and diffuse combustion modes described above. For example, furnace startup is not the only time at which the burner can be on while the bypass apparatus is off. That flame stabilization mode can be continued after startup, and can be alternated with the non-stabilization mode in which the burner is off and the bypass apparatus is on. It may also be appropriate to operate in a mode in which the burner and the bypass apparatus are on simultaneously. Overall target rates of fuel and oxidant injection could then be provided in partial rates at the burner and the bypass apparatus. In this regard,
FIG. 6 shows a modification of thefurnace 300 in which fuel and oxidant valves are arranged to distribute the overall rates of fuel and oxidant injection between theburner mixer body 352 and thebypass mixer body 350. In this arrangement adirectional control valve 400 for fuel is shiftable to initiate, regulate, and terminate flows of fuel to only theburner mixer body 352, to only thebypass mixer body 350, or to both throughout a range of proportional conditions. Adirectional control valve 402 for oxidant is shiftable in the same manner. - This written description sets forth the best mode of carrying out the invention, and describes the invention to enable a person of ordinary skill in the art to make and use the invention, by presenting examples of the elements recited in the claims. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples, which may be available either before or after the application filing date, are intended to be within the scope of the claims if they have structural or method elements that do not differ from the literal language of the claims, or if they have equivalent structural or method elements with insubstantial differences from the literal language of the claims.
Claims (25)
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/542,439 US20080081301A1 (en) | 2006-10-03 | 2006-10-03 | Low NOx combustion |
JP2009531376A JP2010506127A (en) | 2006-10-03 | 2007-09-06 | Low nitrogen oxide combustion |
EP07837795A EP2069688A2 (en) | 2006-10-03 | 2007-09-06 | Low nox combustion |
PCT/US2007/019423 WO2008042075A2 (en) | 2006-10-03 | 2007-09-06 | Low nox combustion |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/542,439 US20080081301A1 (en) | 2006-10-03 | 2006-10-03 | Low NOx combustion |
Publications (1)
Publication Number | Publication Date |
---|---|
US20080081301A1 true US20080081301A1 (en) | 2008-04-03 |
Family
ID=39271292
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/542,439 Abandoned US20080081301A1 (en) | 2006-10-03 | 2006-10-03 | Low NOx combustion |
Country Status (4)
Country | Link |
---|---|
US (1) | US20080081301A1 (en) |
EP (1) | EP2069688A2 (en) |
JP (1) | JP2010506127A (en) |
WO (1) | WO2008042075A2 (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2012075110A1 (en) * | 2010-11-30 | 2012-06-07 | Fives North American Combustion, Inc. | Premix flashback control |
US20130203003A1 (en) * | 2011-08-10 | 2013-08-08 | Bruce E. Cain | Low NOx Fuel Injection for an Indurating Furnace |
US20140272735A1 (en) * | 2013-03-13 | 2014-09-18 | Fives North American Combustion, Inc. | Diffuse Combustion Method and Apparatus |
US20140305128A1 (en) * | 2013-04-10 | 2014-10-16 | Alstom Technology Ltd | Method for operating a combustion chamber and combustion chamber |
WO2016042458A1 (en) * | 2014-09-19 | 2016-03-24 | Ibs Industrie-Brenner-Systeme Gmbh | Method for operating a furnace provided with at least one first burner and furnace arrangement for carrying out the method |
WO2017100270A1 (en) * | 2015-12-09 | 2017-06-15 | Fives North American Combustion, Inc. | Method and apparatus for diffuse combustion of premix |
US11543126B2 (en) | 2019-04-08 | 2023-01-03 | Carrier Corporation | Method and apparatus for mitigating premix burner combustion tone |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BRPI1003906A2 (en) * | 2010-01-21 | 2013-02-26 | Universidade Federal Da Bahia | natural gas combustion system for the control of correlations between thermal radiation soot and nox formation through the use of oxygen enriched combustion |
DE102010045426A1 (en) * | 2010-09-15 | 2012-03-15 | Loi Thermprocess Gmbh | Method and device for heating an industrial furnace |
Citations (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2695216A (en) * | 1950-04-29 | 1954-11-23 | Fmc Corp | Method of operating a nitrogen fixation furnace |
US2737380A (en) * | 1952-04-02 | 1956-03-06 | Henry W Schramm | Method of operating a forge furnace |
US3194295A (en) * | 1962-06-09 | 1965-07-13 | Snecma | Hot gas generating installation |
US3376098A (en) * | 1966-08-29 | 1968-04-02 | Phillips Petroleum Co | Two-chamber burner and process |
US4420929A (en) * | 1979-01-12 | 1983-12-20 | General Electric Company | Dual stage-dual mode low emission gas turbine combustion system |
US4945841A (en) * | 1988-05-25 | 1990-08-07 | Tokyo Gas Company Limited | Apparatus or method for carrying out combustion in a furnace |
US5236327A (en) * | 1990-11-16 | 1993-08-17 | American Gas Association | Low NOx burner |
US5325660A (en) * | 1989-03-20 | 1994-07-05 | Hitachi, Ltd. | Method of burning a premixed gas in a combustor cap |
US5427524A (en) * | 1993-06-07 | 1995-06-27 | Gas Research Institute | Natural gas fired rich burn combustor |
US5482457A (en) * | 1992-10-16 | 1996-01-09 | Asea Brown Boveri Ltd. | Gas-operated premixing burner |
US5584684A (en) * | 1994-05-11 | 1996-12-17 | Abb Management Ag | Combustion process for atmospheric combustion systems |
US5683238A (en) * | 1994-05-18 | 1997-11-04 | Praxair Technology, Inc. | Method for operating a furnace |
US6007326A (en) * | 1997-08-04 | 1999-12-28 | Praxair Technology, Inc. | Low NOx combustion process |
US6282885B1 (en) * | 1999-02-26 | 2001-09-04 | Honda Giken Kogyo Kabushiki Kaisha | Gas turbine engine |
US6606969B2 (en) * | 2000-01-14 | 2003-08-19 | Wsowarmeprozesstechnik Gmbh | Tubular oven |
US20030198909A1 (en) * | 2000-08-30 | 2003-10-23 | Gencor Industries, Inc. | Low emissions burner with premix flame stabilized by a diffusion flame |
US6652265B2 (en) * | 2000-12-06 | 2003-11-25 | North American Manufacturing Company | Burner apparatus and method |
US20040035114A1 (en) * | 2002-08-22 | 2004-02-26 | Akinori Hayashi | Gas turbine combustor, combustion method of the gas turbine combustor, and method of remodeling a gas turbine combustor |
US6824383B2 (en) * | 2002-08-08 | 2004-11-30 | North American Manufacturing Company | Diffuse combustion method and apparatus |
US20060246388A1 (en) * | 2005-04-29 | 2006-11-02 | Hauck Manufacturing Company | Reduced NOx method of combustion |
US20070154855A1 (en) * | 2006-01-05 | 2007-07-05 | Great Southern Flameless, Llc | System, apparatus and method for flameless combustion absent catalyst or high temperature oxidants |
US20070254251A1 (en) * | 2006-04-26 | 2007-11-01 | Jin Cao | Ultra-low NOx burner assembly |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2001240001A1 (en) * | 2000-03-08 | 2001-09-17 | Bristol-Myers Squibb Company | Oral dosage form for administration of the combination of tegafur, uracil, folinic acid, and oxaliplatin and method of using the same |
-
2006
- 2006-10-03 US US11/542,439 patent/US20080081301A1/en not_active Abandoned
-
2007
- 2007-09-06 WO PCT/US2007/019423 patent/WO2008042075A2/en active Application Filing
- 2007-09-06 JP JP2009531376A patent/JP2010506127A/en active Pending
- 2007-09-06 EP EP07837795A patent/EP2069688A2/en not_active Withdrawn
Patent Citations (24)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2695216A (en) * | 1950-04-29 | 1954-11-23 | Fmc Corp | Method of operating a nitrogen fixation furnace |
US2737380A (en) * | 1952-04-02 | 1956-03-06 | Henry W Schramm | Method of operating a forge furnace |
US3194295A (en) * | 1962-06-09 | 1965-07-13 | Snecma | Hot gas generating installation |
US3376098A (en) * | 1966-08-29 | 1968-04-02 | Phillips Petroleum Co | Two-chamber burner and process |
US4420929A (en) * | 1979-01-12 | 1983-12-20 | General Electric Company | Dual stage-dual mode low emission gas turbine combustion system |
US4945841A (en) * | 1988-05-25 | 1990-08-07 | Tokyo Gas Company Limited | Apparatus or method for carrying out combustion in a furnace |
US5325660A (en) * | 1989-03-20 | 1994-07-05 | Hitachi, Ltd. | Method of burning a premixed gas in a combustor cap |
US5658139A (en) * | 1990-11-16 | 1997-08-19 | American Gas Association | Low NOX burner |
US5460513A (en) * | 1990-11-16 | 1995-10-24 | American Gas Association | Low NOx burner |
US5236327A (en) * | 1990-11-16 | 1993-08-17 | American Gas Association | Low NOx burner |
US5482457A (en) * | 1992-10-16 | 1996-01-09 | Asea Brown Boveri Ltd. | Gas-operated premixing burner |
US5427524A (en) * | 1993-06-07 | 1995-06-27 | Gas Research Institute | Natural gas fired rich burn combustor |
US5584684A (en) * | 1994-05-11 | 1996-12-17 | Abb Management Ag | Combustion process for atmospheric combustion systems |
US5683238A (en) * | 1994-05-18 | 1997-11-04 | Praxair Technology, Inc. | Method for operating a furnace |
US6007326A (en) * | 1997-08-04 | 1999-12-28 | Praxair Technology, Inc. | Low NOx combustion process |
US6282885B1 (en) * | 1999-02-26 | 2001-09-04 | Honda Giken Kogyo Kabushiki Kaisha | Gas turbine engine |
US6606969B2 (en) * | 2000-01-14 | 2003-08-19 | Wsowarmeprozesstechnik Gmbh | Tubular oven |
US20030198909A1 (en) * | 2000-08-30 | 2003-10-23 | Gencor Industries, Inc. | Low emissions burner with premix flame stabilized by a diffusion flame |
US6652265B2 (en) * | 2000-12-06 | 2003-11-25 | North American Manufacturing Company | Burner apparatus and method |
US6824383B2 (en) * | 2002-08-08 | 2004-11-30 | North American Manufacturing Company | Diffuse combustion method and apparatus |
US20040035114A1 (en) * | 2002-08-22 | 2004-02-26 | Akinori Hayashi | Gas turbine combustor, combustion method of the gas turbine combustor, and method of remodeling a gas turbine combustor |
US20060246388A1 (en) * | 2005-04-29 | 2006-11-02 | Hauck Manufacturing Company | Reduced NOx method of combustion |
US20070154855A1 (en) * | 2006-01-05 | 2007-07-05 | Great Southern Flameless, Llc | System, apparatus and method for flameless combustion absent catalyst or high temperature oxidants |
US20070254251A1 (en) * | 2006-04-26 | 2007-11-01 | Jin Cao | Ultra-low NOx burner assembly |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2012075110A1 (en) * | 2010-11-30 | 2012-06-07 | Fives North American Combustion, Inc. | Premix flashback control |
US20130203003A1 (en) * | 2011-08-10 | 2013-08-08 | Bruce E. Cain | Low NOx Fuel Injection for an Indurating Furnace |
US20140272735A1 (en) * | 2013-03-13 | 2014-09-18 | Fives North American Combustion, Inc. | Diffuse Combustion Method and Apparatus |
US20160305661A1 (en) * | 2013-03-13 | 2016-10-20 | Fives North American Combustion, Inc. | Diffuse combustion method and apparatus |
US9476589B2 (en) * | 2013-03-13 | 2016-10-25 | Fives North American Combustion, Inc. | Diffuse combustion method and apparatus |
US10145557B2 (en) * | 2013-03-13 | 2018-12-04 | Fives North American Combustion, Inc. | Diffuse combustion method and apparatus |
US20140305128A1 (en) * | 2013-04-10 | 2014-10-16 | Alstom Technology Ltd | Method for operating a combustion chamber and combustion chamber |
US10544736B2 (en) * | 2013-04-10 | 2020-01-28 | Ansaldo Energia Switzerland AG | Combustion chamber for adjusting a mixture of air and fuel flowing into the combustion chamber and a method thereof |
WO2016042458A1 (en) * | 2014-09-19 | 2016-03-24 | Ibs Industrie-Brenner-Systeme Gmbh | Method for operating a furnace provided with at least one first burner and furnace arrangement for carrying out the method |
WO2017100270A1 (en) * | 2015-12-09 | 2017-06-15 | Fives North American Combustion, Inc. | Method and apparatus for diffuse combustion of premix |
US10215408B2 (en) | 2015-12-09 | 2019-02-26 | Fives North American Combustion, Inc. | Method and apparatus for diffuse combustion of premix |
US11543126B2 (en) | 2019-04-08 | 2023-01-03 | Carrier Corporation | Method and apparatus for mitigating premix burner combustion tone |
Also Published As
Publication number | Publication date |
---|---|
JP2010506127A (en) | 2010-02-25 |
EP2069688A2 (en) | 2009-06-17 |
WO2008042075A2 (en) | 2008-04-10 |
WO2008042075A3 (en) | 2008-06-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20080081301A1 (en) | Low NOx combustion | |
US8033254B2 (en) | Submerged combustion vaporizer with low NOx | |
US6652265B2 (en) | Burner apparatus and method | |
US6824383B2 (en) | Diffuse combustion method and apparatus | |
US20130260323A1 (en) | METHOD AND APPARATUS FOR A DUAL MODE BURNER YIELDING LOW NOx EMISSION | |
US9909755B2 (en) | Low NOx combustion method and apparatus | |
US10145557B2 (en) | Diffuse combustion method and apparatus | |
US9995481B2 (en) | Method and apparatus for a dual mode burner yielding low NOx emission | |
JPS62153624A (en) | Method and device for operating pulse pilot burner | |
KR101031534B1 (en) | LOW NOx INDUSTRIAL WASTE GAS BURNER | |
EP3258170B1 (en) | Low nox combustion | |
US20140272737A1 (en) | Staged Combustion Method and Apparatus | |
CN110056869A (en) | A kind of burner | |
US10215408B2 (en) | Method and apparatus for diffuse combustion of premix | |
US7959431B2 (en) | Radiant tube with recirculation | |
RU2432530C1 (en) | Burner for combustion of gaseous and/or liquid fuel with reduced exhaust of nitrogen oxides | |
KR20130070873A (en) | Apparatus and method for burning material | |
RU2215938C1 (en) | Injection jumbo burner | |
JP3553495B2 (en) | Boiler equipment | |
RU98537U1 (en) | BURNER FOR COMBUSTION OF GAS AND / OR LIQUID FUEL WITH THE REDUCED EMISSION OF NITROGEN OXIDES | |
KR900002317B1 (en) | Apparatus and operation of a pulse-fired burner | |
KR100571129B1 (en) | pilot burner | |
KR20010088895A (en) | A burner and a combustion system to use the burner |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: NORTH AMERICAN MANUFACTURING COMPANY, LTD., THE, O Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HANNUM, MARK C.;ROBERTSON, THOMAS F.;NEVILLE, THOMAS B.;AND OTHERS;REEL/FRAME:018379/0252;SIGNING DATES FROM 20060926 TO 20060928 |
|
AS | Assignment |
Owner name: FIVES NA CORP., OHIO Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:THE NORTH AMERICAN MANUFACTURING COMPANY, LTD.;REEL/FRAME:021849/0795 Effective date: 20080731 Owner name: FIVES NORTH AMERICAN COMBUSTION, INC., OHIO Free format text: CHANGE OF NAME;ASSIGNOR:FIVES NA CORP.;REEL/FRAME:021849/0887 Effective date: 20081014 |
|
STCB | Information on status: application discontinuation |
Free format text: EXPRESSLY ABANDONED -- DURING EXAMINATION |