Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
  • F23L7/00—Supplying non-combustible liquids or gases, other than air, to the fire, e.g. oxygen, steam
  • F23L7/002—Supplying water
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
  • F02C7/20—Mounting or supporting of plant; Accommodating heat expansion or creep
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C3/00—Gas-turbine plants characterised by the use of combustion products as the working fluid
  • F02C3/20—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products
  • F02C3/30—Adding water, steam or other fluids for influencing combustion, e.g. to obtain cleaner exhaust gases
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/20—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone
  • F23D14/22—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone with separate air and gas feed ducts, e.g. with ducts running parallel or crossing each other
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/46—Details, e.g. noise reduction means
  • F23D14/72—Safety devices, e.g. operative in case of failure of gas supply
  • F23D14/78—Cooling burner parts

Definitions

• Gas burners are employed in a wide variety of commercial and industrial applications.
• gas burners may be used to vaporize cryogenic fluid such as liquefied natural gas.
• cryogenic fluid can be heated in a submerged combustion vaporizer (SCV).
• SCV submerged combustion vaporizer
• An SCV typically includes heat exchanger tubing and a water tank in which the tubing is submerged. The cryogenic fluid flows through the tubing.
• the SCV further includes a gas burner that fires into a duct system.
• the duct system has perforated sections, known as sparger tubes, that direct the burner exhaust to bubble upward through the water in the tank. The exhaust then heats the water and the submerged tubing so that the cryogenic fluid flowing through the tubing also becomes heated.
• Nitrogen oxides (NOx) in the exhaust are carried upward from the tank through a flue and discharged into the atmosphere with the exhaust.
• NOx Nitrogen oxides
• FIG. 1A is a perspective, cross-sectional view of an embodiment of a burner assembly according to the invention.
• Fig. IB is a detail of a portion of the burner assembly illustrated in Fig. 1A.
• FIG. 2 is a partial cross-sectional elevation view of a main burner incorporating a water supply and a spray nozzle that can be used in the burner assembly illustrated in Fig. 1A.
• Fig. 3A is a top view of a portion of the main burner illustrated in Fig. 2.
• Fig. 3B is an elevation view of the portion of the main burner illustrated in Fig. 3A.
• Fig. 4 is a cross-sectional elevation view of a distal end portion of the main burner illustrated in Fig. 2.
• Fig. 5A is an elevation view of a portion of a water spray subassembly that can be used in the burner assembly illustrated in Fig. 1.
• Fig. 5B is a top view of the water spray subassembly illustrated in Fig. 5A.
• Fig. 6 is an enlarged cross-sectional elevation view of a distal end portion of the main burner illustrated in Fig. 2.
• Fig. 7 is an enlarged cross-sectional elevation view of another embodiment of a main burner.
• the burner assembly in the illustrated examples is a water cooled burner that is mostly or completely free of refractory material.
• a fuel source which is preferably a supply of natural gas; and an oxidant source, which is preferably an air blower, provide the burner with streams of those reactants.
• the burner assembly preferably includes a water injection system.
• This system includes a water line that communicates with a water source.
• the water source is preferably a tank of stored water, but could optionally be the publicly available water supply.
• the burner assembly is especially useful in combination with LNG submerged combustion vaporizers (SCVs).
• SCVs LNG submerged combustion vaporizers
• Such vaporizers are useful for heating and/or vaporization of cryogenic and low temperature fluids. Though frequently used with oxygen, nitrogen, ethylene, ammonia, and propane, such vaporizer systems are optionally used for vaporization of LNG, e.g., in base-load and peak-shaving regasification facilities.
• the SCV is an indirect fired heat exchanger with the burner and a process tube coil that may be contained within a single vessel.
• the design is based on the submerged exhaust principle whereby the burner combustion products are discharged into a water bath, which is used as the heat transfer media for vaporizing the LNG in the tube coil.
• combustion air is generally introduced into the burner at two locations. Most of the air enters an upper volute section (secondary combustion air), with the remainder (primary combustion air) being supplied to the region around the fuel gas injector. With this arrangement, the burner fires upwardly into the central section between the two volutes, where the combustion gases are co-reacted with the secondary combustion air.
• the secondary combustion air enters the upper volute via a tangential inlet, imparting a swirling motion to the air. This results in intimate mixing with the combustion gases rising from the burner and subsequent gas recirculation back along the axis of the burner before
• the SCV employs a gas nozzle design with water injection that controls the single burner at maximum operating conditions to produce NOx emissions, corrected to 3% dry oxygen (0 2 ), as low as 30 parts per million (ppm) or less.
• the water injection can be performed using a water spray nozzle cone having, for example, a vertical 60 degree to 90 degree solid cone angle.
• a hollow cone such as a 210 degree hollow cone, is used to direct water as it is injected into the system.
• the hollow cone nozzle provides improved results as compared to a solid cone. It is believed that the improved performance results from the fact that the water spray is introduced to combustion air at a different location, thus cooling the flame. Accordingly, NOx emissions from the burner can be reduced to 20 ppm or lower.
• this invention provides a burner assembly such as assembly 10 configured for combusting fuel in a combustion zone to reduce NOx emissions.
• the burner assembly 10 includes an air nozzle
• the air nozzle conduit has an interior region to accommodate air flow 56.
• the burner assembly 10 also includes a gas nozzle subassembly such as gas nozzle assembly 28 including a fuel gas conduit 34 (e.g., including a fuel gas pipe) positioned at least partially within the interior region of the air nozzle conduit.
• the fuel gas conduit is configured to direct fuel in a direction generally along the axis for delivery to or toward the combustion zone.
• the burner assembly 10 further includes an annular passage defined between the air nozzle conduit and the fuel gas conduit (e.g., an annular passage between the main burner air nozzle and cooling coil 24 and the fuel gas pipe 34).
• the annular passage is configured to direct air in a direction generally along the axis for delivery to or toward the combustion zone.
• a water spray subassembly including a water outlet configured to direct water at an angle with respect to the axis.
• the water outlet is further configured to direct water in a direction toward the annuiar passage for mixing with air upstream of the combustion zone.
• Water is used by way of example only, as other coolant compositions which may or may not include water may be used.
• the water outlet of the water spray subassembly optionally includes a water spray nozzle such as nozzle 26 or 90.
• the water spray nozzle can be configured to direct water in a direction radially outwardly with respect to the axis.
• the water spray nozzle such as nozzle 90, may be configured to direct water at a spray angle A3 greater than 180 degrees such that an angle A4 between the axis and a spray direction of the water is less than 90 degrees, or at a spray angle A3 from 190 to 230 degrees such that an angle A4 between the axis and a spray direction of the water is less than 85 degrees, or at a spray angle A3 of about 210 degrees such that an angle A4 between the axis and a spray direction of the water is about 75 degrees.
• the water spray nozzle can therefore be configured to direct water in a hollow cone such that water is not directed outwardly from the water spray nozzle along the axis A.
• the water spray subassembly optionally includes a water conduit such as water pipe 44 positioned to extend within the fuel gas conduit, the water spray nozzle being coupled to a distal end of the water conduit.
• the burner assembly optionally includes an inner annular passage defined between the water conduit and the fuel gas conduit, the inner annular passage being configured to direct fuel in a direction generally along the axis for delivery to the combustion zone.
• the air nozzle conduit of the air nozzle subassembly may include cooling colls through which water can be circulated.
• This invention also provides a method for retrofitting an existing burner assembly for combusting fuel in a combustion zone with reduced NOx emissions.
• the method can be used with a burner assembly having an air nozzle subassembly including an air nozzle conduit, such as the main burner air nozzle and cooling coil 24; a gas nozzle subassembly including a fuel gas conduit, such as the fuel gas pipe 34; and a water spray subassembly including a water outlet, such as nozzle 26 or 90.
• the method includes configuring the water outlet to direct water at an angle with respect to an axis of the air nozzle conduit and in a direction toward an annular passage between the air nozzle conduit and the fuel gas conduit for mixing with air upstream of the combustion zone.
• the method optionally includes configuring a water spray nozzle, such as nozzle 26 or 90, of the water spray subassembly to direct water in a direction radially outwardly with respect to the axis. Specifically, it includes configuring the water spray nozzle to direct water at a spray angle A3 greater than 180 degrees such that an angle A4 between the axis and a spray direction of the water is less than 90 degrees, or at a spray angle A3 from 190 to 230 degrees such that an angle A4 between the axis and a spray direction of the water is less than 85 degrees, or at a spray angle A3 of about 210 degrees such that an angle A4 between the axis and a spray direction of the water is about 75 degrees.
• a water spray nozzle such as nozzle 26 or 90
• the method optionally includes configuring the water spray nozzle to direct water in a hollow cone such that water is not directed outwardly from the water spray nozzle along the axis A.
• This invention also provides a method for using a burner system for combusting fuel in a combustion zone with reduced NOx emissions.
• the method includes directing fuel in a direction generally along an axis for delivery to the combustion zone through a fuel gas conduit; directing air toward the combustion zone in a direction generally along the axis through an annular passage defined between an air nozzle conduit and the fuel gas conduit; and directing water at an angle with respect to the axis and in a direction toward the annular passage for mixing with air upstream of the combustion zone.
• the directing water step of the method optionally includes directing water in a direction radially outwardly with respect to the axis. For example, it includes directing water at a spray angle A3 greater than 180 degrees such that an angle A4 between the axis and a spray direction of the water is less than 90 degrees, or at a spray angle A3 from 190 to 230 degrees such that an angle A4 between the axis and a spray direction of the water is iess than 85 degrees, or at a spray angle A3 of about 210 degrees such that an angle A4 between the axis and a spray direction of the water is about 75 degrees.
• the directing water step may also include directing water in a hollow cone from a water spray nozzle such that water is not directed outwardly from the water spray nozzle along the axis.
• a burner assembly 10 includes a top volute 12 and a bottom volute 14 for the circulation of air.
• a cone assembly 16 having a water jacket extends between the bottom volute 14 and the top volute 12, thus providing a passage for the flow of combustion products.
• a partial deck support 18 is associated with the top volute 12.
• a burner top plate 20 encloses the top volute 12.
• Burner assembly 10 is provided with a main burner 22 incorporating a water supply and a spray nozzle, which will be described in further detail later.
• Fig. IB shows a cross-sectional view of a distal end portion of the main burner 22. It includes a spray nozzle 26 as will be described in detail below.
• Main burner 22 generally includes an air nozzle subassembly, a gas nozzle subassembly, and a water spray subassembly. Specifically, main burner 22 includes a main burner air nozzle and PATENT
• the main burner air nozzle and cooling coil 24 is coupled to receive a supply of air that generally flows upwardly through the main burner air nozzle and cooling coil 24.
• Main burner 22 also includes a gas nozzle assembly 28 and a water nozzle assembly 30 that is positioned at least partially within the gas nozzle assembly 28.
• the gas nozzle assembly 28 is attached via a coupling 32 to a fuel gas pipe 34.
• fuel gas pipe 34 is coupled via a tee 36 to a fuel gas pipe 38.
• the fuel gas pipe 38 is in turn coupled via an elbow 40 to provide a fuel gas inlet 42.
• the inlet 42 is connected to a source of fuel gas (not shown).
• the water nozzle assembly 30 is coupled to a source of water via a water pipe 44.
• the water pipe 44 is coupled via an elbow 46 to a water pipe 48, which is in turn coupled via an elbow 50 to provide a water inlet 52.
• the inlet 52 is connected to a source of water or other coolant (not shown).
• a passageway is defined for fuel gas flow 54 in a general direction toward the distal end portion of the main burner 22.
• a passage is defined for water flow 58 toward the distal end portion of the main burner 22 such that the water flow 58 generally flows in a passage or conduit disposed within the fuel gas flow 54.
• a passageway is defined between the cooling coil 24 and the fuel gas pipe 34 for air flow 56, also in the general direction toward the distal end portion 23 of the main burner 22.
• main burner 22 is configured for combustion of the mixture of fuel and air including the fuel of fuel gas flow 54, the air of air flow 56, and air in the base of volute 14.
• This combustion generates a flame shown generally at 25 in FIG. 2, extending in a direction along the axis of the main burner 22, which is oriented along a vertical axis A in the embodiment illustrated in Fig. 2.
• the base of the flame will generally be positioned a short distance beyond the distal end of the main burner 22 along axis A. Referring back to Fig. 1A, the flame will extend toward or into the cone assembly 16.
• main burner 22 includes the water spray nozzle 26 that extends above a top plate 62 of the main burner 22.
• a pair of lugs 64 offset by 180° in this embodiment, extend radially outward from the PATENT
• Main burner 22 also includes a pipe 66 having a wall with a plurality of ports 68 or holes formed therein through which fuel gas flow 54 from within the pipe 66 can be directed.
• Fig. 4 the distal end portion of the main burner 22 is shown in a cross-sectional view in order to illustrate the general directions of fuel gas flow 54 and water flow 58. These flows are directed generally in the same direction along the axis of the main burner 22 (e.g., in a direction parallel or approximately parallel to the axis A).
• the water flow 58 moves through the water pipe 44 of the water spray subassembly.
• the fuel gas flow 54 moves in the annular passage defined between the inner surface of the fuel gas pipe 34 and the outer surface of the water pipe 44.
• the water spray subassembly includes a water pipe portion 70 of water pipe 44 extending from a pipe coupling 72.
• Upper centering members 74 (three being illustrated by way of example only as spokes in this embodiment) extend radiantly outward from the water pipe portion 70 and is generally located a distance D from the distal end of the pipe coupling 72.
• the upper centering plate 74 has a thickness T and is configured to provide a centering function such that water pipe portion 70 of water pipe 44 can be centered within the fuel gas pipe 34 of the main burner 22.
• a lower centering plate 76 is also provided for this purpose.
• Fig. 5A The components of the water spray subassembly are shown in Fig. 5A. It has a length L selected depending upon the size of the main burner 22. As is illustrated in Fig. 5B, the upper centering spokes 74 extend outwardly to a distance similar to a diameter of the lower centering plate 76, and such spokes are spaced from one another at an angle Al (e.g., 120°).
• Al an angle
• the water spray nozzle 26 in this embodiment is a solid cone spray nozzle having a water spray cone angle A2. Accordingly, water flow 58 moves through the water pipe portion 70, through the coupling 72, and through a nozzle opening of water spray nozzle 26 to be PATENT
• the water spray cone angle A2 is the included angle of the solid spray cone generated by the water spray nozzle 26.
• the main burner 22 also includes, at its distal end portion, a mounting ring 78, which provides a support for one or more gaskets 80 or seals.
• the mounting ring 78 and gaskets 80 provide a means for sealing against the plate 62 of the main burner 22, thereby reducing or preventing the flow of fuel gas through the space between the coupling 72 and an aperture 73 in the end plate 62.
• the seal is shown in Fig. 6 in broken lines, such that the position of the mounting ring 78 and gasket 80 wouid be adjusted such that the gasket 80 contacts a bottom surface 63 of the end plate 62, thereby providing the seal.
• This position of the gasket 80 is shown in broken lines in Fig. 6.
• substantially ail of the fuel gas flow 54 is discharged through the gas nozzle assembly 28 through the ports 68 in the pipe forming the gas nozzle assembly 28.
• Fig. 7 shows another exemplary embodiment of this invention illustrated in a cross-sectional, enlarged view of the distai end portion of a main burner22. Elements illustrated in FIG, 7 which correspond to the elements described above with respect to FIGS. 1A-6 have been designated by corresponding reference numbers increased by one hundred.
• the nozzle 90 structure illustrated in Fig. 7 differs somewhat from the nozzle 26 illustrated in Fig. 6.
• the water spray nozzle 90 provides a hollow cone spray instead of a solid cone water spray.
• the nozzle 90 redirects water flow 158 so that it will be discharged in a hollow cone radially outward from the axis A of the main burner. In this way, the water is redirected radially outward and away from the base of the flame that will form at a location beyond the distal end of the main burner along axis A.
• a hollow cone spray shape at the distal end of the burner, it is possible to redirect water flow in a spray shape away from the flame. Also, such a spray shape makes it possible to redirect the water spray toward or into the path of air flow upstream of the combustion zone.
• one suitable nozzle embodiment is a hollow cone spray nozzle such as a Type PJ nozzle available from Delavan Spray Technologies of Deiavan Ltd, which is a wholly owned subsidiary of Goodrich Corporation. Such a nozzle is designed to produce a hollow cone spray pattern using an external 'pintle' deflector.
• the water spray nozzle 90 is configured to form a water spray hollow cone angle A3 as illustrated in Fig. 7. Although a wide variety of water spray cone angles A3 may be selected, a spray angle A3 greater than 180° is used for reasons explained later. When the water spray angle A3 is greater than 180°, the angle A4 between the axis of the main burner and a spray direction of the water is less than 90°.
• the spray angle A3 is in a range from 190° to 230° such that an angle A4 between the axis and the spray direction of the water is from 65 to 85°. For example, in one embodiment the spray angle A3 is about 210° such that an angle A4 between the axis and the spray direction of the water is about 75°.
• the water is introduced into the angular passage 29 that extends between the inner surface of main burner air nozzle and cooling coil 24 and the outer surface of the fuel gas pipe 34 or the outer surface of the gas nozzle assembly 28. In other words, water is directed into the air flow 56 as it passes through the main burner air nozzle and cooling coil 24.
• This direction of the water spray entrains the water into the air flow 56 prior to and upstream of the combustion zone, thus further reducing NOx emissions generated by the flame of the burner. Additionally, the water spray encourages mixing with air upstream of the combustion zone rather than directing water along the axis A into the base of the flame.
• the water is introduced into the air using a water spray nozzle at the distal end portion of the burner assembly in the illustrated embodiments, it is contemplated that the water could be introduced at any location in the air upstream from the location of the flame, preferably within the passageway through which air flow 56 is introduced into the area of combustion.
• water can be introduced at any location along the path of water flow 58, including at the base in the area of the elbow 46 or anywhere else along the path of water flow 58.
• water flow can be introduced into the air flow 56 radially inwardly from the structure of the main burner air nozzle and cooling coil 24.
• water can be introduced from the cooling coil into the air flow 56 by placing one or more nozzles in the cooling coil facing radially inward toward the fuel gas pipe 34 or gas nozzle assembly 28.
• a portion of the water flowing through the cooling coil can be utilized for the reduction of NOx emissions by PATENT
• water spray nozzle 90 redirects water flow 158 so that it will extend in a hollow cone radially outwardly from the axis A of the main burner. In this way, the water is redirected radially outward and away from the base of the flame that will form at a location beyond the distal end of the main burner along axis A. This facilitates entrainment of water into the air upstream of the point where the air enters the combustion zone, thus reducing NOx emissions.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)

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Citations (5)

Family Cites Families (9)

• 2011
  • 2011-06-10 US US13/157,336 patent/US20120255472A1/en not_active Abandoned
• 2012
  • 2012-03-09 SG SG2013074737A patent/SG194114A1/en unknown
  • 2012-03-09 WO PCT/US2012/028442 patent/WO2012138447A1/en active Application Filing
  • 2012-03-09 RU RU2013149146/06A patent/RU2013149146A/ru not_active Application Discontinuation
  • 2012-03-09 KR KR1020137029241A patent/KR20140027975A/ko not_active Application Discontinuation
  • 2012-03-09 CN CN201280026879.6A patent/CN103562519A/zh active Pending
  • 2012-03-09 JP JP2014503665A patent/JP2014510257A/ja active Pending
  • 2012-03-09 EP EP12767351.5A patent/EP2694790A4/de not_active Withdrawn
  • 2012-03-09 AU AU2012240534A patent/AU2012240534A1/en not_active Abandoned
  • 2012-03-09 CA CA2832107A patent/CA2832107A1/en not_active Abandoned
• 2013
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