EP1892470A1 - Burner with center air jet - Google Patents
Burner with center air jet Download PDFInfo
- Publication number
- EP1892470A1 EP1892470A1 EP06254290A EP06254290A EP1892470A1 EP 1892470 A1 EP1892470 A1 EP 1892470A1 EP 06254290 A EP06254290 A EP 06254290A EP 06254290 A EP06254290 A EP 06254290A EP 1892470 A1 EP1892470 A1 EP 1892470A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- burner
- gas
- zone
- annular zone
- recited
- 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.)
- Granted
Links
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 41
- 239000001301 oxygen Substances 0.000 claims abstract description 41
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 41
- 239000000446 fuel Substances 0.000 claims abstract description 36
- 238000002485 combustion reaction Methods 0.000 claims abstract description 27
- 238000000034 method Methods 0.000 claims abstract description 25
- 239000007789 gas Substances 0.000 claims description 52
- 239000003245 coal Substances 0.000 claims description 37
- 239000012159 carrier gas Substances 0.000 claims description 23
- 230000003750 conditioning effect Effects 0.000 claims description 10
- 230000015572 biosynthetic process Effects 0.000 claims description 9
- 239000012530 fluid Substances 0.000 claims description 6
- 238000004891 communication Methods 0.000 claims description 5
- 238000009826 distribution Methods 0.000 claims description 2
- 230000001105 regulatory effect Effects 0.000 claims 3
- 229930195733 hydrocarbon Natural products 0.000 description 6
- 150000002430 hydrocarbons Chemical class 0.000 description 5
- 239000004215 Carbon black (E152) Substances 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 239000002803 fossil fuel Substances 0.000 description 3
- 230000033228 biological regulation Effects 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000009841 combustion method Methods 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D1/00—Burners for combustion of pulverulent fuel
- F23D1/02—Vortex burners, e.g. for cyclone-type combustion apparatus
Definitions
- the present invention relates generally to fuel burners and, in particular, to a new and useful pulverized coal burner and method of combustion which achieves low NO x emissions by supplying oxygen directly to the center of the burner flame in a manner so as to create a fuel rich internal combustion zone within the burner flame and accelerate fuel combustion.
- NO x is a byproduct produced during the combustion of coal and other fossil fuels.
- Environmental concerns regarding the effects of NO x have prompted enactment of NO x emissions regulations requiring sharp NO x emission reductions from industrial and utility power plants in several countries including the United States.
- Current commercial methods and apparatuses for reducing NO x emissions have been successful in lowering NO x emissions from the levels emitted in previous years; however, further advances, beyond those of currently known methods and apparatuses, are needed to maintain compliance with current NO x emissions regulations.
- a variety of low NO x burners are commercially available and widely used to fire pulverized coal (PC) and other fossil fuels in a NO x reducing manner as compared to conventional burners. Examples of such burners are The Babcock & Wilcox Company's DRB-XCL ® and DRB-4Z ® burners.
- Common to these and other low NO, burner designs is an axial coal nozzle surrounded by multiple air zones which supply secondary air (SA).
- SA secondary air
- PC suspended in a primary air (PA) stream is injected into the furnace through an axial coal nozzle, as an axial jet, with little or no radial deflection. Ignition of the PC is accomplished by swirling SA, thereby causing recirculation of hot gases along the incoming fuel jet.
- a fraction of the SA is supplied to an air zone in close proximity to the coal nozzle and swirled to a relatively greater extent than the SA supplied to the other air zones to accomplish ignition.
- the remaining SA from the burner is introduced through air zones further outboard in the burner utilizing less swirl, so as to mix slowly into the burner flame, thereby providing fuel rich conditions in the root of the flame.
- Such conditions promote the generation of hydrocarbons which compete for available oxygen and serve to destroy NO x and/or inhibit the oxidation of fuel-bound and molecular nitrogen to NO x .
- NO x emissions can further be reduced by staged combustion, wherein the burner is provided with less than stoichiometric oxygen for complete combustion.
- a fuel rich environment results at the burner flame.
- the fuel rich environment inhibits NO x formation by forcing NO x precursors to compete with uncombusted fuel in an oxygen lean environment.
- Combustion is then staged by providing excess oxygen to the boiler at a point above the burner wherein the excess fuel combusts at a lower temperature, thus precluding the production of thermal NO x as the combustion occurs at a lower temperature away from the burner flame.
- Staging also serves to lessen oxygen concentrations during the combustion process which inhibits oxidation of fuel bound nitrogen (fuel NO x ).
- Oxygen for staged combustion is normally provided in the form of air via air staging ports, commonly called Over Fire Air (OFA) ports, in a system utilizing low NO x burners.
- OFA Over Fire Air
- U.S. Patent No. 5,697,306 to LaRue and U.S. Patent No. 5,199,355 to LaRue , herein incorporated by reference, disclose low NO x burners that may be combined with air staged combustion methods to further reduce NO x emissions.
- low NO x burners tend to form long flames and produce higher levels of unburned combustibles.
- Long flames are not always desirable as they may be incompatible with furnace depth or height, and can impair boiler operation by causing flame impingement, slagging, and/or boiler tube corrosion.
- the present invention solves the aforementioned problems associated with delayed combustion produced by typical low NO x burners and introduces a new burner apparatus and method of combusting fossil fuels to further reduce NO x emissions in commercial and utility boilers.
- a burner according to the present invention is suitable for firing pulverized coal (PC) or gaseous hydrocarbons.
- the present invention comprises an axial zone concentrically surrounded by a first annular zone.
- the first annular zone provides fuel to the burner at a predetermined velocity so as to create a fuel jet exiting the burner and subsequently forming a burner flame via combustion in the presence of oxygen.
- the axial zone produces a center air jet piercing the burner flame along its internal axis.
- the center air jet provides oxygen along the center axis of the burner flame, allowing the flame to combust from the inside out, while maintaining an overall fuel rich environment in the flame root thereby suppressing NO x formation.
- Additional oxygen supplied by second and third annular zones concentrically surrounding the first annular zone further reduces NO x formation while providing a means for accelerating combustion.
- Flow conditioning devices of the second and third annular zones aerodynamically suppress fuel jet expansion. Within this aerodynamic suppression, swirl from the air exiting the second and third annular zones creates an internal recirculation zone along the outer boundary of the flame zone which inhibits NO x formation.
- the internal recirculation zone causes NO x formed along the outer air-rich periphery of the flame to recirculate back into the fuel rich flame core.
- the hotter flame temperature resulting from the inside out combustion of the center air jet, cause uncombusted hydrocarbon radicals to scavenge available oxygen within the IRZ, thereby suppressing the formation of NO x , and reducing NO back to other nitrogenous species.
- a wider, shorter flame envelope results as flame temperature increases due to the accelerated combustion of fuel from the inside out and outside in within the IRZ.
- Another aspect of the present invention can be considered a method of reducing NO x emissions in a center air jet burner comprising, providing a burner having an axial zone concentrically surrounded by a first annular zone, providing the axial zone with a first gas comprising oxygen, wherein the first gas exits the axial zone at a velocity between about 5000 ft/min and about 10,000 ft/min, providing the first annular zone with a carrier gas comprising a pulverized coal, wherein the carrier gas exits the axial zone at a velocity between about 3000 ft/min and about 5000 ft/min.
- Yet another aspect of the present invention can be considered a method of reducing NO x emissions in a center air jet burner comprising, providing a four zone burner, wherein the innermost zone is an axial zone concentrically surrounded by a first annular zone, which in turn is concentrically surrounded by a second annular zone, which in turn is concentrically surrounded by a third annular zone, providing the axial zone with a first gas comprising oxygen, providing the first annular zone with a carrier gas comprising a pulverized coal, providing the second annular zone with a second gas comprising oxygen, providing the third annular zone with a third gas comprising oxygen, providing the burner with the carrier gas at a velocity greater than about 3000 ft/min, providing the burner with the first gas at a velocity greater than the carrier gas, providing the burner with the second gas at a velocity less than the carrier gas, providing the burner with the third gas at a velocity greater than the carrier gas, combusting the pulverized coal in the carrier gas stream from the inside of the stream
- FIG. 1. is a schematic sectional view of an embodiment of the present invention.
- FIG. 2 is a schematic view of an embodiment of the present invention wherein arrows identify the flow paths of air and coal;
- FIG. 3 is a outside view of a burner assembly embodiment of the present invention identifying the location of feeding duct 9;
- FIG. 4 is a schematic cross sectional view of an embodiment of the present invention which identifies the concentric zones of the present invention.
- FIG. 1 there is shown a schematic sectional view of a burner depicted in accordance with the present invention.
- Axial pipe 6, defining an axial zone 25 therein, is concentrically surrounded by a first annular pipe 3 wherein the area between the two pipes defines a first annular zone 11.
- feeder duct 9 Radially interposed between a portion of first annular pipe 3 and axial pipe 6 is feeder duct 9 such that axial pipe 6 and windbox 51 are in fluid communication with opposite ends of feeder duct 9.
- FIG. 3 a top view of feeder duct 9 radially interposed between at least a portion of first annular pipe 3 and axial pipe 6 (not shown in FIG. 3) is provided, such that axial pipe 6 and windbox 51 are in fluid communication with opposite ends of feeder duct 9.
- secondary air is supplied by forced draft fans (not shown), preheated in air heaters (not shown), and under pressure to windbox 51.
- Feeder duct 9 in turn provides secondary air from windbox 51 to axial pipe 6, at a rate controlled by damper 10.
- An air flow measuring device 12 quantifies the secondary air flowing through feeder duct 9.
- a pulverizer (not shown) grinds coal which is conveyed with primary air through a conduit connected to a burner elbow 2.
- An igniter (not shown) may be positioned on the axis of the burner, penetrating elbow 2, plug 5, and extending through axial pipe 6.
- Pulverized coal and primary air (PA/PC) 1 pass through the burner elbow 2.
- the pulverized coal generally travels along the outer radius of elbow 2 and concentrates into a stream along the outer radius at the elbow exit.
- the pulverized coal enters first annular zone 11 and encounters a deflector 4 which redirects the coal stream into plug 5 and disperses the coal.
- Axial pipe 6 is attached to the downstream side of plug 5.
- First annular pipe 3 expands in section 3A to form a larger diameter section 3B.
- the dispersed coal travels along first annular zone 11 wherein bars and chevrons 7 provide more uniform distribution of the pulverized coal before exiting the first annular zone 11 as a fuel jet.
- Wedged shaped pieces 9A and 9B (Fig. 3) provide a more contoured flow path for the PA/PC 1 as it travels past feeder duct 9.
- a flow conditioning device 30 may be used to disperse the coal to increase the rate at which it interacts with the secondary air.
- Flow conditioning device 30 may consist of swirl vanes and/or one or more bluff bodies to locally obstruct flow and induce swirl.
- Another flow conditioning device 13 may be positioned at the end of axial pipe 6 to provide more uniform flow to secondary air as it exits axial zone 25 into burner throat 8, and out into the furnace (not shown) in the form of a center air jet.
- Flow conditioning device 13 can be vanes, perforated plates, or other commonly used devices to provide more uniform flow. In some cases, flow conditioning device 13 may provide swirl to the core air to further accelerate coal ignition and reduce emissions.
- An aspect pertaining to the operational method of the present invention is the creation of a center air jet within with the fuel jet stream as it exits throat 8 and enters the furnace.
- the center air jet will have a velocity exceeding that of the fuel jet so as to create a velocity gradient within the flame which promotes ignition of the fuel from the inside out utilizing the oxygen from the center air jet.
- Optimum operating conditions occur when PA/PC exits the first annular zone at a velocity between about 3,000 ft/min and about 5,000 ft/min, and more preferably between about 3,500 ft/min and about 4,500 ft/min. Optimum operating conditions further occur when secondary air exits axial zone 25 at a velocity between about 5,000 ft/min and 10,000 ft/min, and more preferably between about 5,500 ft/min and 7,500 ft/min.
- Damper 15 controls the entry of additional secondary air to the burner assembly.
- damper 15 allows secondary air to flow into a second annular zone 16 concentrically surrounding first annular zone 11, wherein the second annular zone 16 is defined as the area between pipe 3B and barrel 19.
- Damper 15 further allows secondary air to flow into third annular zone 17 concentrically surrounding second annular zone 16, wherein the third annular zone 16 is defined as the area between barrel 19 and outside burner zone wall 38.
- Damper 15 can be positioned to preferentially throttle secondary air to one zone over the other, or to supply lesser quantities of secondary air to both zones.
- An igniter (not shown) may optionally be situated in annular zone 17, if not through pipe 6.
- Optimal operating conditions for utilizing all three annular zones to provide secondary air for combustion occur when between about 20 percent and about 40 percent of the total oxygen provided to the burner by secondary air is provided through axial zone 25, more preferably between about 25 percent and 35 percent.
- About 10 percent to about 30 percent of the total oxygen provided to the burner by secondary air is provided through second annular zone 16, more preferably between about 15 to about 25 percent.
- About 40 percent to about 70 percent of the total oxygen provided to the burner by secondary air is provided through third annular air zone 17, more preferably between about 50 percent to about 65 percent.
- Air flow measurement device 18 measures the secondary air flow through second annular zone 16 and third annular zone 17. Optimum operating conditions occur when secondary air exits second annular zone 16 at a velocity between about 3000 ft/min and about 4500 ft/min, more preferably between about 3100 ft/min and about 3900 ft/min. Further, wherein secondary air exits third annular zone 17 at a velocity between about 5500 ft/min and about 7500 ft/min, more preferably the velocity is between about 5700 ft/min and about 6700 ft/min.
- Optimal air shear conditions generally occur when the inner diameter of the axial zone is between about 9 inches and about 20 inches, the inner diameter of the first annular zone is between about 15 inches and about 30 inches, the inner diameter of the second annular zone is between about 20 inches and about 40 inches, and wherein the inner diameter of the third annual zone is between about 22 and about 50 inches.
- Adjustable vanes 21 are situated in the second annular zone 16 to provide swirled secondary air prior to exiting second annular zone 16.
- Other air distribution devices such as perforated plates and ramps may also be installed at the end of second annular zone 16.
- Fixed vanes 22A and adjustable vanes 22B impart swirl to the secondary air passing through third annular zone 17.
- vane 23 which may alternatively be placed in the middle of the air zone exit, deflects part of the air away from the primary combustion zone.
- FIG. 2 a graphical depiction, wherein arrows identify the flow paths of secondary air and PA/PC 1, is provided.
- a gas comprising oxygen at a greater concentration than air may be utilized in place of all or part of the secondary air.
- a hydrocarbon fuel other than pulverized coal may be utilized as fuel.
- a center conduit may be placed within axial zone 25 such that axial pipe 6 concentrically surrounds the center conduit.
- the center conduit may house an igniter, an oil atomizer or gas alternative, or a lance for introduction of concentrated oxygen or additional hydrocarbon fuel into the flame core either axially or by radial dispersion.
- a plurality of center conduits may be placed within axial zone 25 such that axial pipe 6 concentrically surrounds each of the plurality of conduits.
- the plurality of center conduits may provide concentrated oxygen in more than one stream, or at least one of the conduits may provide additional coal or other hydrocarbon fuel for combustion.
- multiple feeder ducts and/or booster fans or conduits may be utilized to provide additional secondary air or oxygen to axial zone 25.
- staged combustion is utilized with the burner and NO x reduction methods of the present invention to further reduce NO x emissions.
- an alternative air ducting system may be devised wherein secondary air is ducted through outer wall 51 B of windbox 51 and fed into axial zone 25 though the outer radius of an enlarged burner elbow or elsewhere to form a axial zone 25 in fluid connection with the windbox 51.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
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- Fluidized-Bed Combustion And Resonant Combustion (AREA)
- Pre-Mixing And Non-Premixing Gas Burner (AREA)
Abstract
Description
- Field of Invention
- The present invention relates generally to fuel burners and, in particular, to a new and useful pulverized coal burner and method of combustion which achieves low NOx emissions by supplying oxygen directly to the center of the burner flame in a manner so as to create a fuel rich internal combustion zone within the burner flame and accelerate fuel combustion.
- Background of the Invention
- NOx is a byproduct produced during the combustion of coal and other fossil fuels. Environmental concerns regarding the effects of NOx have prompted enactment of NOx emissions regulations requiring sharp NOx emission reductions from industrial and utility power plants in several countries including the United States. Current commercial methods and apparatuses for reducing NOx emissions have been successful in lowering NOx emissions from the levels emitted in previous years; however, further advances, beyond those of currently known methods and apparatuses, are needed to maintain compliance with current NOx emissions regulations.
- A variety of low NOx burners are commercially available and widely used to fire pulverized coal (PC) and other fossil fuels in a NOx reducing manner as compared to conventional burners. Examples of such burners are The Babcock & Wilcox Company's DRB-XCL® and DRB-4Z® burners. Common to these and other low NO, burner designs is an axial coal nozzle surrounded by multiple air zones which supply secondary air (SA). During operation, PC suspended in a primary air (PA) stream, is injected into the furnace through an axial coal nozzle, as an axial jet, with little or no radial deflection. Ignition of the PC is accomplished by swirling SA, thereby causing recirculation of hot gases along the incoming fuel jet.
- Typically a fraction of the SA is supplied to an air zone in close proximity to the coal nozzle and swirled to a relatively greater extent than the SA supplied to the other air zones to accomplish ignition. The remaining SA from the burner is introduced through air zones further outboard in the burner utilizing less swirl, so as to mix slowly into the burner flame, thereby providing fuel rich conditions in the root of the flame. Such conditions promote the generation of hydrocarbons which compete for available oxygen and serve to destroy NOx and/or inhibit the oxidation of fuel-bound and molecular nitrogen to NOx.
- NOx emissions can further be reduced by staged combustion, wherein the burner is provided with less than stoichiometric oxygen for complete combustion. A fuel rich environment results at the burner flame. The fuel rich environment inhibits NOx formation by forcing NOx precursors to compete with uncombusted fuel in an oxygen lean environment. Combustion is then staged by providing excess oxygen to the boiler at a point above the burner wherein the excess fuel combusts at a lower temperature, thus precluding the production of thermal NOx as the combustion occurs at a lower temperature away from the burner flame. Staging also serves to lessen oxygen concentrations during the combustion process which inhibits oxidation of fuel bound nitrogen (fuel NOx).
- Oxygen for staged combustion is normally provided in the form of air via air staging ports, commonly called Over Fire Air (OFA) ports, in a system utilizing low NOx burners.
U.S. Patent No. 5,697,306 to LaRue , andU.S. Patent No. 5,199,355 to LaRue , herein incorporated by reference, disclose low NOx burners that may be combined with air staged combustion methods to further reduce NOx emissions. - Unlike conventional burners, low NOx burners tend to form long flames and produce higher levels of unburned combustibles. Long flames are not always desirable as they may be incompatible with furnace depth or height, and can impair boiler operation by causing flame impingement, slagging, and/or boiler tube corrosion.
- Long flames result from an insufficient air supply to the fuel jet as it proceeds into the furnace. SA from the outer air zones of low NOx burners do not effectively penetrate the downstream fuel jet, such that unburned fuel persists due to a lack of air supply along the flame axis. High levels of unburned fuel are undesirable in both furnaces with OFA and those without. Unburned combustibles in the form of unburned carbon and CO reduce boiler efficiency and add operation expenses, whereas unburned pulverized coal, by nature of its abrasiveness, may cause undesirable erosive damage to the furnace itself.
- Incomplete air/fuel mixing ahead of an OFA system can cause excessive amounts of unburned fuel to persist up to the OFA ports. When large amounts of unburned fuel try to burn with air at the OFA zone, NOx formation can increase, thereby minimizing or negating the benefit of staged combustion with OFA. In addition it becomes increasingly difficult to completely burn out these combustibles at and beyond the OFA ports, such that they add to inefficiency and operational difficulties.
- The present invention solves the aforementioned problems associated with delayed combustion produced by typical low NOx burners and introduces a new burner apparatus and method of combusting fossil fuels to further reduce NOx emissions in commercial and utility boilers.
- A burner according to the present invention is suitable for firing pulverized coal (PC) or gaseous hydrocarbons. The present invention comprises an axial zone concentrically surrounded by a first annular zone. The first annular zone provides fuel to the burner at a predetermined velocity so as to create a fuel jet exiting the burner and subsequently forming a burner flame via combustion in the presence of oxygen. The axial zone produces a center air jet piercing the burner flame along its internal axis. The center air jet provides oxygen along the center axis of the burner flame, allowing the flame to combust from the inside out, while maintaining an overall fuel rich environment in the flame root thereby suppressing NOx formation.
- Additional oxygen supplied by second and third annular zones concentrically surrounding the first annular zone further reduces NOx formation while providing a means for accelerating combustion. Flow conditioning devices of the second and third annular zones aerodynamically suppress fuel jet expansion. Within this aerodynamic suppression, swirl from the air exiting the second and third annular zones creates an internal recirculation zone along the outer boundary of the flame zone which inhibits NOx formation. The internal recirculation zone (IRZ) causes NOx formed along the outer air-rich periphery of the flame to recirculate back into the fuel rich flame core. The hotter flame temperature, resulting from the inside out combustion of the center air jet, cause uncombusted hydrocarbon radicals to scavenge available oxygen within the IRZ, thereby suppressing the formation of NOx, and reducing NO back to other nitrogenous species. A wider, shorter flame envelope results as flame temperature increases due to the accelerated combustion of fuel from the inside out and outside in within the IRZ.
- Another aspect of the present invention can be considered a method of reducing NOx emissions in a center air jet burner comprising, providing a burner having an axial zone concentrically surrounded by a first annular zone, providing the axial zone with a first gas comprising oxygen, wherein the first gas exits the axial zone at a velocity between about 5000 ft/min and about 10,000 ft/min, providing the first annular zone with a carrier gas comprising a pulverized coal, wherein the carrier gas exits the axial zone at a velocity between about 3000 ft/min and about 5000 ft/min.
- Yet another aspect of the present invention can be considered a method of reducing NOx emissions in a center air jet burner comprising, providing a four zone burner, wherein the innermost zone is an axial zone concentrically surrounded by a first annular zone, which in turn is concentrically surrounded by a second annular zone, which in turn is concentrically surrounded by a third annular zone, providing the axial zone with a first gas comprising oxygen, providing the first annular zone with a carrier gas comprising a pulverized coal, providing the second annular zone with a second gas comprising oxygen, providing the third annular zone with a third gas comprising oxygen, providing the burner with the carrier gas at a velocity greater than about 3000 ft/min, providing the burner with the first gas at a velocity greater than the carrier gas, providing the burner with the second gas at a velocity less than the carrier gas, providing the burner with the third gas at a velocity greater than the carrier gas, combusting the pulverized coal in the carrier gas stream from the inside of the stream with the first gas, combusting the pulverized coal in the carrier gas stream from the outside with the second gas and the third gas, utilizing the velocity gradient between the four annular zones to create a recirculation zone within a burner flame, suppressing NOx formation and accelerating combustion by recirculation of uncombusted coal and oxygen in the burner flame.
- The various features of novelty which characterize the present invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, it's operating advantages and specific benefits attained by it's uses, reference is made to the accompanying drawings and descriptive matter in which the preferred embodiments of the invention are illustrated.
- FIG. 1. is a schematic sectional view of an embodiment of the present invention;
- FIG. 2 is a schematic view of an embodiment of the present invention wherein arrows identify the flow paths of air and coal;
- FIG. 3 is a outside view of a burner assembly embodiment of the present invention identifying the location of
feeding duct 9; and - FIG. 4 is a schematic cross sectional view of an embodiment of the present invention which identifies the concentric zones of the present invention.
- Referring to the drawings, generally where like numerals designate the same or functionally similar features, throughout the several views and first to FIG. 1, there is shown a schematic sectional view of a burner depicted in accordance with the present invention.
Axial pipe 6, defining anaxial zone 25 therein, is concentrically surrounded by a firstannular pipe 3 wherein the area between the two pipes defines a firstannular zone 11. Radially interposed between a portion of firstannular pipe 3 andaxial pipe 6 isfeeder duct 9 such thataxial pipe 6 andwindbox 51 are in fluid communication with opposite ends offeeder duct 9. - Referring now to FIG. 3, a top view of
feeder duct 9 radially interposed between at least a portion of firstannular pipe 3 and axial pipe 6 (not shown in FIG. 3) is provided, such thataxial pipe 6 andwindbox 51 are in fluid communication with opposite ends offeeder duct 9. - Referring back to FIG. 1, secondary air is supplied by forced draft fans (not shown), preheated in air heaters (not shown), and under pressure to
windbox 51.Feeder duct 9 in turn provides secondary air fromwindbox 51 toaxial pipe 6, at a rate controlled bydamper 10. An airflow measuring device 12 quantifies the secondary air flowing throughfeeder duct 9. - A pulverizer (not shown) grinds coal which is conveyed with primary air through a conduit connected to a
burner elbow 2. An igniter (not shown) may be positioned on the axis of the burner, penetratingelbow 2,plug 5, and extending throughaxial pipe 6. - Pulverized coal and primary air (PA/PC) 1 pass through the
burner elbow 2. The pulverized coal generally travels along the outer radius ofelbow 2 and concentrates into a stream along the outer radius at the elbow exit. The pulverized coal enters firstannular zone 11 and encounters adeflector 4 which redirects the coal stream intoplug 5 and disperses the coal.Axial pipe 6 is attached to the downstream side ofplug 5. Firstannular pipe 3 expands insection 3A to form alarger diameter section 3B. The dispersed coal travels along firstannular zone 11 wherein bars andchevrons 7 provide more uniform distribution of the pulverized coal before exiting the firstannular zone 11 as a fuel jet. Wedged shapedpieces past feeder duct 9. - A
flow conditioning device 30 may be used to disperse the coal to increase the rate at which it interacts with the secondary air.Flow conditioning device 30 may consist of swirl vanes and/or one or more bluff bodies to locally obstruct flow and induce swirl. - Another
flow conditioning device 13 may be positioned at the end ofaxial pipe 6 to provide more uniform flow to secondary air as it exitsaxial zone 25 intoburner throat 8, and out into the furnace (not shown) in the form of a center air jet.Flow conditioning device 13 can be vanes, perforated plates, or other commonly used devices to provide more uniform flow. In some cases,flow conditioning device 13 may provide swirl to the core air to further accelerate coal ignition and reduce emissions. - An aspect pertaining to the operational method of the present invention is the creation of a center air jet within with the fuel jet stream as it exits
throat 8 and enters the furnace. Preferably, the center air jet will have a velocity exceeding that of the fuel jet so as to create a velocity gradient within the flame which promotes ignition of the fuel from the inside out utilizing the oxygen from the center air jet. - Optimum operating conditions occur when PA/PC exits the first annular zone at a velocity between about 3,000 ft/min and about 5,000 ft/min, and more preferably between about 3,500 ft/min and about 4,500 ft/min. Optimum operating conditions further occur when secondary air exits
axial zone 25 at a velocity between about 5,000 ft/min and 10,000 ft/min, and more preferably between about 5,500 ft/min and 7,500 ft/min. -
Damper 15 controls the entry of additional secondary air to the burner assembly. When in theopen position damper 15 allows secondary air to flow into a secondannular zone 16 concentrically surrounding firstannular zone 11, wherein the secondannular zone 16 is defined as the area betweenpipe 3B andbarrel 19.Damper 15 further allows secondary air to flow into thirdannular zone 17 concentrically surrounding secondannular zone 16, wherein the thirdannular zone 16 is defined as the area betweenbarrel 19 and outsideburner zone wall 38.Damper 15 can be positioned to preferentially throttle secondary air to one zone over the other, or to supply lesser quantities of secondary air to both zones. An igniter (not shown) may optionally be situated inannular zone 17, if not throughpipe 6. - Optimal operating conditions for utilizing all three annular zones to provide secondary air for combustion occur when between about 20 percent and about 40 percent of the total oxygen provided to the burner by secondary air is provided through
axial zone 25, more preferably between about 25 percent and 35 percent. About 10 percent to about 30 percent of the total oxygen provided to the burner by secondary air is provided through secondannular zone 16, more preferably between about 15 to about 25 percent. About 40 percent to about 70 percent of the total oxygen provided to the burner by secondary air is provided through thirdannular air zone 17, more preferably between about 50 percent to about 65 percent. - Air
flow measurement device 18 measures the secondary air flow through secondannular zone 16 and thirdannular zone 17. Optimum operating conditions occur when secondary air exits secondannular zone 16 at a velocity between about 3000 ft/min and about 4500 ft/min, more preferably between about 3100 ft/min and about 3900 ft/min. Further, wherein secondary air exits thirdannular zone 17 at a velocity between about 5500 ft/min and about 7500 ft/min, more preferably the velocity is between about 5700 ft/min and about 6700 ft/min. - Optimal air shear conditions generally occur when the inner diameter of the axial zone is between about 9 inches and about 20 inches, the inner diameter of the first annular zone is between about 15 inches and about 30 inches, the inner diameter of the second annular zone is between about 20 inches and about 40 inches, and wherein the inner diameter of the third annual zone is between about 22 and about 50 inches.
-
Adjustable vanes 21 are situated in the secondannular zone 16 to provide swirled secondary air prior to exiting secondannular zone 16. Other air distribution devices such as perforated plates and ramps may also be installed at the end of secondannular zone 16.Fixed vanes 22A andadjustable vanes 22B impart swirl to the secondary air passing through thirdannular zone 17. As swirled air leaves thirdannular zone 17,vane 23, which may alternatively be placed in the middle of the air zone exit, deflects part of the air away from the primary combustion zone. - Referring now to FIG. 2, a graphical depiction, wherein arrows identify the flow paths of secondary air and PA/PC 1, is provided.
- In an alternative embodiment, a gas comprising oxygen at a greater concentration than air may be utilized in place of all or part of the secondary air.
- In another alternative embodiment, a hydrocarbon fuel other than pulverized coal may be utilized as fuel.
- I n another alternative embodiment a center conduit may be placed within
axial zone 25 such thataxial pipe 6 concentrically surrounds the center conduit. In such an embodiment the center conduit may house an igniter, an oil atomizer or gas alternative, or a lance for introduction of concentrated oxygen or additional hydrocarbon fuel into the flame core either axially or by radial dispersion. - In another alternative embodiment a plurality of center conduits may be placed within
axial zone 25 such thataxial pipe 6 concentrically surrounds each of the plurality of conduits. In such an embodiment the plurality of center conduits may provide concentrated oxygen in more than one stream, or at least one of the conduits may provide additional coal or other hydrocarbon fuel for combustion. - In another embodiment multiple feeder ducts and/or booster fans or conduits may be utilized to provide additional secondary air or oxygen to
axial zone 25. - In another embodiment staged combustion is utilized with the burner and NOx reduction methods of the present invention to further reduce NOx emissions.
- In yet another embodiment an alternative air ducting system may be devised wherein secondary air is ducted through
outer wall 51 B ofwindbox 51 and fed intoaxial zone 25 though the outer radius of an enlarged burner elbow or elsewhere to form aaxial zone 25 in fluid connection with thewindbox 51. - While the specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise as appreciated by one of ordinary skill in the art without departing from the scope of the present invention.
Claims (37)
- A center air jet burner comprising:an axial zone concentrically surrounded by a first annular zone,a feeder duct radially interposed between a portion of the first annular zone and the axial zone, wherein the feeder duct provides a gas comprising oxygen to the axial zone, anda means for regulating flow of the gas through the feeder duct.
- A burner as recited in claim 1, wherein the axial zone contains a flow conditioning device.
- A burner as recited in claim 1 or claim 2, wherein the first annular zone contains a flow conditioning device.
- A burner as recited in anyone of the preceding claims, wherein the first annular zone contains a means of providing more uniform coal distribution.
- A burner as recited in anyone of the preceding claims, further comprising a means for providing the first annular zone with a combustible fuel.
- A burner as recited in anyone of the preceding claim, wherein the first annular zone is concentrically surrounded by a second annular zone, and wherein the second annular zone is concentrically surrounded by a third annular zone.
- A burner as recited in claim 6, further comprising a means for providing air to the second annular zone, and a means for providing air to the third annular zone.
- A burner as recited in claim 6 or 7, further comprising a vane in the second annular zone.
- A burner as recited in anyone of claims 6 to 8, further comprising a vane in the third annular zone.
- A burner as recited in claim 7, further comprising a means for regulating air flow to the second annular zone, and a means for regulating air flow to the third annular zone.
- A burner as recited in anyone of the preceding claims, wherein a windbox is in fluid communication with the second annular zone and the third annular zone.
- A burner as recited in claim 11, wherein a windbox is in fluid communication with the axial zone.
- A burner as recited in anyone of the preceding claims, wherein the axial zone is in fluid communication with a primary air duct.
- A burner as recited in anyone of the preceding claims, wherein an igniter resides within the axial zone.
- A burner as recited in anyone of the preceding claims, further comprising a conduit concentrically surrounded by the axial zone.
- A burner as recited in claim 15, wherein the conduit includes a means for radially dispersing a gas into the axial zone.
- A burner as recited in claim 15 or 16, wherein the conduit includes a means for longitudinally dispersing a gas into the axial zone.
- A center air jet burner comprising:an axial zone concentrically surrounded by a first annular zone,wherein the diameter of the axial zone is between about 9 inches and about 20 inches and the diameter of the first annular zone is between about 15 inches and 30 inches.
- A burner as recited in claim 18, further comprising a second annular zone concentrically surrounding the first annular zone, wherein the diameter of the second annular zone is between about 20 inches to about 40 inches.
- A burner as recited in claim 19, further comprising a third annular zone concentrically surrounding the second annular zone, wherein the diameter of the third annular zone is between about 22 inches to about 50 inches.
- A burner as recited in claim 20, further comprising a conduit concentrically surrounded by the axial zone.
- A method of reducing NOx emissions in a pulverized coal burner comprising the steps of;providing a four zone burner, wherein the innermost zone is an axial zone concentrically surrounded by a first annular zone, which in turn is concentrically surrounded by a second annular zone, which in turn is concentrically surrounded by a third annular zone;providing the axial zone with a first gas comprising oxygen;providing the first annular zone with a carrier gas comprising a pulverized coal;providing the second annular zone with a second gas comprising oxygen;providing the third annular zone with a third gas comprising oxygen;providing the burner with the carrier gas at a velocity greater than about 3000 ft/min;providing the burner with the first gas at a velocity greater than the carrier gas;providing the burner with the second gas at a velocity less than the carrier gas;providing the burner with the third gas at a velocity greater than the carrier gas;combusting the pulverized coal in the carrier gas stream from the inside of the stream with the first gas;combusting the pulverized coal in the carrier gas stream from the outside with the second gas and the third gas;utilizing the velocity gradient between the four annular zones to create a recirculation zone within a burner flame; andsuppressing NOx formation and accelerating combustion by recirculation uncombusted coal and oxygen in the burner flame.
- The method as recited in claim 22, further comprising swirling the second gas prior to reaching the burner flame.
- The method as recited in claim 22 or claim 23, further comprising swirling the carrier gas prior to combustion.
- The method as recited in anyone of claims 22 to 24, further comprising swirling the third gas prior to combustion.
- The method as recited in anyone of claims 22 to 25, further comprising swirling the first gas prior to combustion.
- The method as recited in anyone of claims 22 to 26, wherein the first gas comprises more than 21 percent oxygen.
- The method as recited in anyone of claims 22 to 27, wherein the second gas comprises more than 21 percent oxygen.
- The method as recited in anyone of claims 22 to 28, wherein the third gas comprises more than 21 percent oxygen.
- A method of reducing NOx emissions in a pulverized coal burner comprising the steps of;providing a burner having an axial zone concentrically surrounded by a first annular zone;providing the axial zone with a first gas comprising oxygen, wherein the first gas exits the axial zone at a velocity between about 5000 ft/min and about 10,000 ft/min;providing the first annular zone with a carrier gas comprising a pulverized coal, wherein the carrier gas exits the first annular zone at a velocity between about 3000 ft/min and about 5000 ft/min.
- The method as recited in claim 30, further comprising;providing a burner with a second annular zone concentrically surrounding the first annular zone and a third annular zone concentrically surrounding the second annular zone;providing the burner with a second gas comprising oxygen, wherein the second gas exits the second annular zone at a velocity between about 3000 ft/min and about 4500 ft/min, andproviding the burner with a third gas comprising oxygen, wherein the third gas exits the third annular zone at a velocity between about 5500 ft/min and about 7500 ft/min.
- The method as recited in claim 31, wherein the first gas exits the axial zone at a velocity between about 5500 ft/min and 7500 ft/min, and wherein the carrier gas exits the first annular zone at a velocity between about 3500 ft/min and 4500 ft/min.
- The method as recited in claim 32, wherein the second gas exits the second annular zone at a velocity between about 3100 ft/min and about 3900 ft/min, and wherein the third gas exits the third annular zone at a velocity between about 5700 ft/min and about 6700 ft/min.
- The method as recited in claim 32 or 33, further comprising the step of providing a burner flame with oxygen wherein about 20 percent to about 40 percent of the total oxygen is provided by the first gas through the axial zone, about 10 percent to about 30 percent of the total oxygen is provided by the second gas through the second annular zone, and about 40 percent to about 70 percent of the oxygen is provided by the third gas through the third annular zone.
- The method as recited in claim 34, further comprising the step of swirling at least one of the group consisting of the first gas, the second gas, the third gas, and the carrier gas prior to reaching the burner flame.
- The method as recited in claim 34, further comprising the steps of; combusting the pulverized coal in the carrier gas stream from the inside of the stream with the first gas, combusting the pulverized coal in the carrier gas stream from the outside with the second gas and the third gas;providing a means for creating a recirculation zone within the burner flame; and suppressing NOx formation and accelerating combustion by recirculation of uncombusted coal and oxygen in the burner flame.
- The method as recited in claim 34, further comprising the step of utilizing a flow conditioning means for conditioning gas flow within at least one of the group consisting of the axial zone, the first annular zone, the second annular zone, and the third annular zone.
Priority Applications (13)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PL09170949.3T PL2138765T3 (en) | 2006-08-16 | 2006-08-16 | Method of combustion |
ES09151678.1T ES2636594T3 (en) | 2006-08-16 | 2006-08-16 | Central air jet burner |
PL09151678T PL2051005T3 (en) | 2006-08-16 | 2006-08-16 | Burner with center air jet |
EP09170949.3A EP2138765B1 (en) | 2006-08-16 | 2006-08-16 | Method of combustion |
ES06254290T ES2358273T3 (en) | 2006-08-16 | 2006-08-16 | NOx EMISSION REDUCTION PROCEDURE IN A PULVERIZED CARBON BURNER. |
EP06254290A EP1892470B8 (en) | 2006-08-16 | 2006-08-16 | Method of Reducing NOx Emissions in a Pulverized Coal Burner |
AT06254290T ATE497126T1 (en) | 2006-08-16 | 2006-08-16 | METHOD FOR REDUCING NOX EMISSIONS IN A CARBON BURNER |
DK09170949.3T DK2138765T3 (en) | 2006-08-16 | 2006-08-16 | Method of combustion |
PL06254290T PL1892470T3 (en) | 2006-08-16 | 2006-08-16 | Method of Reducing NOx Emissions in a Pulverized Coal Burner |
DE602006019860T DE602006019860D1 (en) | 2006-08-16 | 2006-08-16 | Method of reducing NOx emissions in a pulverized coal burner |
ES09170949.3T ES2576008T3 (en) | 2006-08-16 | 2006-08-16 | Combustion method |
EP09151678.1A EP2051005B1 (en) | 2006-08-16 | 2006-08-16 | Burner with center air jet |
DK06254290.7T DK1892470T3 (en) | 2006-08-16 | 2006-08-16 | Process for reducing NOx emissions in a pulverized-coal burner |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP06254290A EP1892470B8 (en) | 2006-08-16 | 2006-08-16 | Method of Reducing NOx Emissions in a Pulverized Coal Burner |
Related Child Applications (4)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP09170949.3A Division EP2138765B1 (en) | 2006-08-16 | 2006-08-16 | Method of combustion |
EP09151678.1A Division EP2051005B1 (en) | 2006-08-16 | 2006-08-16 | Burner with center air jet |
EP09151678.1 Division-Into | 2009-01-29 | ||
EP09170949.3 Division-Into | 2009-09-22 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP1892470A1 true EP1892470A1 (en) | 2008-02-27 |
EP1892470B1 EP1892470B1 (en) | 2011-01-26 |
EP1892470B8 EP1892470B8 (en) | 2011-03-09 |
Family
ID=37564416
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP09170949.3A Active EP2138765B1 (en) | 2006-08-16 | 2006-08-16 | Method of combustion |
EP09151678.1A Active EP2051005B1 (en) | 2006-08-16 | 2006-08-16 | Burner with center air jet |
EP06254290A Active EP1892470B8 (en) | 2006-08-16 | 2006-08-16 | Method of Reducing NOx Emissions in a Pulverized Coal Burner |
Family Applications Before (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP09170949.3A Active EP2138765B1 (en) | 2006-08-16 | 2006-08-16 | Method of combustion |
EP09151678.1A Active EP2051005B1 (en) | 2006-08-16 | 2006-08-16 | Burner with center air jet |
Country Status (6)
Country | Link |
---|---|
EP (3) | EP2138765B1 (en) |
AT (1) | ATE497126T1 (en) |
DE (1) | DE602006019860D1 (en) |
DK (2) | DK2138765T3 (en) |
ES (3) | ES2576008T3 (en) |
PL (3) | PL1892470T3 (en) |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
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US4333405A (en) * | 1979-08-16 | 1982-06-08 | L. & C. Steinmuller Gmbh | Burner for combustion of powdered fuels |
DE3535873A1 (en) * | 1985-10-08 | 1987-04-09 | Theo Dipl Ing Burkard | Process for low-NOx combustion by means of a free-radical-forming medium |
US4924784A (en) * | 1984-02-27 | 1990-05-15 | International Coal Refining Company | Firing of pulverized solvent refined coal |
US5231937A (en) * | 1990-03-07 | 1993-08-03 | Hitachi, Ltd. | Pulverized coal burner, pulverized coal boiler and method of burning pulverized coal |
US5651320A (en) * | 1993-07-30 | 1997-07-29 | Babcock Lentjes Kraftwerkstechnik Gmbh | Burner for burning powdered fuel |
DE10201558A1 (en) | 2001-01-18 | 2002-08-14 | Alstom Power Boiler Gmbh | Burner for particulate fuel introduces primary air and secondary air through different tubes with flow stabilising area upstream in flow direction of primary mixture |
EP1306614A1 (en) | 2000-08-04 | 2003-05-02 | Babcock-Hitachi Kabushiki Kaisha | Solid fuel burner and combustion method using solid fuel burner |
US20040074427A1 (en) * | 2002-05-15 | 2004-04-22 | Hisashi Kobayashi | Low NOx combustion |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
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US5199355A (en) | 1991-08-23 | 1993-04-06 | The Babcock & Wilcox Company | Low nox short flame burner |
US5697306A (en) | 1997-01-28 | 1997-12-16 | The Babcock & Wilcox Company | Low NOx short flame burner with control of primary air/fuel ratio for NOx reduction |
-
2006
- 2006-08-16 PL PL06254290T patent/PL1892470T3/en unknown
- 2006-08-16 DK DK09170949.3T patent/DK2138765T3/en active
- 2006-08-16 PL PL09151678T patent/PL2051005T3/en unknown
- 2006-08-16 DE DE602006019860T patent/DE602006019860D1/en active Active
- 2006-08-16 ES ES09170949.3T patent/ES2576008T3/en active Active
- 2006-08-16 EP EP09170949.3A patent/EP2138765B1/en active Active
- 2006-08-16 EP EP09151678.1A patent/EP2051005B1/en active Active
- 2006-08-16 EP EP06254290A patent/EP1892470B8/en active Active
- 2006-08-16 ES ES09151678.1T patent/ES2636594T3/en active Active
- 2006-08-16 AT AT06254290T patent/ATE497126T1/en active
- 2006-08-16 PL PL09170949.3T patent/PL2138765T3/en unknown
- 2006-08-16 ES ES06254290T patent/ES2358273T3/en active Active
- 2006-08-16 DK DK06254290.7T patent/DK1892470T3/en active
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4333405A (en) * | 1979-08-16 | 1982-06-08 | L. & C. Steinmuller Gmbh | Burner for combustion of powdered fuels |
US4924784A (en) * | 1984-02-27 | 1990-05-15 | International Coal Refining Company | Firing of pulverized solvent refined coal |
DE3535873A1 (en) * | 1985-10-08 | 1987-04-09 | Theo Dipl Ing Burkard | Process for low-NOx combustion by means of a free-radical-forming medium |
US5231937A (en) * | 1990-03-07 | 1993-08-03 | Hitachi, Ltd. | Pulverized coal burner, pulverized coal boiler and method of burning pulverized coal |
US5651320A (en) * | 1993-07-30 | 1997-07-29 | Babcock Lentjes Kraftwerkstechnik Gmbh | Burner for burning powdered fuel |
EP1306614A1 (en) | 2000-08-04 | 2003-05-02 | Babcock-Hitachi Kabushiki Kaisha | Solid fuel burner and combustion method using solid fuel burner |
DE10201558A1 (en) | 2001-01-18 | 2002-08-14 | Alstom Power Boiler Gmbh | Burner for particulate fuel introduces primary air and secondary air through different tubes with flow stabilising area upstream in flow direction of primary mixture |
US20040074427A1 (en) * | 2002-05-15 | 2004-04-22 | Hisashi Kobayashi | Low NOx combustion |
Also Published As
Publication number | Publication date |
---|---|
EP2051005A3 (en) | 2010-06-09 |
EP2138765A3 (en) | 2010-09-22 |
EP2138765A2 (en) | 2009-12-30 |
DE602006019860D1 (en) | 2011-03-10 |
PL2051005T3 (en) | 2017-10-31 |
PL1892470T3 (en) | 2011-07-29 |
DK2138765T3 (en) | 2016-07-25 |
EP1892470B1 (en) | 2011-01-26 |
ES2636594T3 (en) | 2017-10-06 |
EP1892470B8 (en) | 2011-03-09 |
EP2051005B1 (en) | 2017-06-14 |
EP2051005A2 (en) | 2009-04-22 |
DK1892470T3 (en) | 2011-03-21 |
ATE497126T1 (en) | 2011-02-15 |
ES2576008T3 (en) | 2016-07-04 |
ES2358273T3 (en) | 2011-05-09 |
PL2138765T3 (en) | 2016-09-30 |
EP2138765B1 (en) | 2016-03-30 |
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