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EP4400766A1 - Brûleur à faibles émissions de nox et procédé de fonctionnement pour réduire la formation de nox appliqué dans le procédé de frittage et/ou de durcissement de boulettes de minerai de fer - Google Patents

Brûleur à faibles émissions de nox et procédé de fonctionnement pour réduire la formation de nox appliqué dans le procédé de frittage et/ou de durcissement de boulettes de minerai de fer Download PDF

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Publication number
EP4400766A1
EP4400766A1 EP21956274.1A EP21956274A EP4400766A1 EP 4400766 A1 EP4400766 A1 EP 4400766A1 EP 21956274 A EP21956274 A EP 21956274A EP 4400766 A1 EP4400766 A1 EP 4400766A1
Authority
EP
European Patent Office
Prior art keywords
burner
fuel gas
descending
flow
fin
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.)
Pending
Application number
EP21956274.1A
Other languages
German (de)
English (en)
Other versions
EP4400766A4 (fr
Inventor
David James Retallack
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fct Holdings Pty Ltd
Original Assignee
Fct Holdings Pty Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Fct Holdings Pty Ltd filed Critical Fct Holdings Pty Ltd
Publication of EP4400766A1 publication Critical patent/EP4400766A1/fr
Publication of EP4400766A4 publication Critical patent/EP4400766A4/fr
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/46—Details
    • F23D14/62—Mixing devices; Mixing tubes
    • F23D14/64—Mixing devices; Mixing tubes with injectors
    • 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 
    • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • F23C9/08—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber for reducing temperature in combustion chamber, e.g. for protecting walls of combustion chamber
    • 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
    • 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
    • F23D14/24—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 at least one of the fluids being submitted to a swirling motion
    • 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
    • F23D14/70—Baffles or like flow-disturbing devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
    • F23D2900/11401—Flame intercepting baffles forming part of burner head
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
    • F23D2900/21—Burners specially adapted for a particular use
    • F23D2900/21003—Burners specially adapted for a particular use for heating or re-burning air or gas in a duct

Definitions

  • the present patent of invention relates to low NOx emission burner and operating method for reducing NOx formation applied to iron ore pellet sintering and/or enduring method, more specifically a burner of the type used in industrial combustion for reducing NOx emission through the rapid mixing of fuel gas with the descending flow of oxidant before self-ignition and flame stabilization.
  • Said innovative burner integrates an operating method wherein the fuel gas jets discharged from the collector ring mix firstly with the oxidant and continue, in combustion, in a rotating movement, through the descending duct flow, also known as furnace downcomer.
  • the even distribution of the fuel gas around the perimeter of the passage section of the downcomer, allied to the rotational effect of the downcomer flow allows the rapid mixing of fuel gas with oxygen diluted in this current.
  • the nitrogen oxide gases NO and NO 2 are typically formed during the combustion process, particularly industrial.
  • the highest temperatures are observed around the stoichiometric zones of the flames and can reach 1925° C/3500 F for the combustion of natural gas mixed with ambient air.
  • the maximum thermal NOx is formed in these zones.
  • NOx in burning processes depends on several factors, such as: fuel composition, system operation mode, burner design and combustion chamber.
  • One of the determinant parameters of this pollutant is the presence of temperature peaks which occur in certain regions of the flame, for which reason the goal of many burner manufacturers and designers of combustion systems with low NOx emission is to reduce or eliminate the occurrence of said peaks.
  • the burners used in the sintering process and/or endurance of iron ore pellets use small quantities of primary air, provided by blower or fan, and the remaining oxidant that is necessary for the combustion reaction is obtained from the circulating hot gas flow, which is usually a mixture of hot air with combustion products.
  • the oxygen content in this hot circulating flow is usually higher than 10% (volumetric basis).
  • the staging of the injection of fuel gas is a commonly used technique for the control of NOx emissions, since it allows the dispersion of fuel gas inside the flame envelope, and thus reduces the temperature peaks in the flame and respective NOx formation. However, this technique does not allow a significant reduction of the NOx emissions in sintering furnaces and/or endurance of NOx iron ore pellets.
  • the flame of the burner used in the process is formed by consuming oxidants at extremely high temperatures, around 850 to 1050 °C.
  • the burner flame In the second place, even with the staged injection of the fuel gas, for example, using lances surrounding the primary air jet, the burner flame has a large envelope shape being relatively wide and more or less long.
  • the combustion reaction restricts the envelope volume, as, in this case, the envelope flame or jet type flame, always tends to present average higher temperature and thus higher NOx, in comparison with the reaction which occurs spread throughout the oven or furnace volume.
  • the I-Jet type burner provided by FCT Combustion - is an example of burners used in the iron ore pellet industries.
  • This forms jet type flame, with the chemical combustion reaction concluded in the flame envelope formed in the front of the burner.
  • the primary air and staging of fuel gas injection in contact and mixed with the ambient furnace gases, form the flame, which can be longer or shorter, wider, or narrower.
  • it is still a jet type flame, with high temperature. Due to the staging of the fuel gas injection, the average temperature of the flame can be reduced, which can help with the NOx reduction.
  • the reduction is not significant, particularly in the process of iron ore pellet sintering and/or enduring at high temperature. This is largely due to the significant contribution of the high temperature of the oxidant used in combustion.
  • This flow circulates through the zones of the iron ore pellet sintering and/or enduring furnace of the moving grate type.
  • the flow of hot gases from the downcomer is directly heated by the burner flame to a temperature of around 1300 °C/1400°C, necessary for the process of endurance of iron ore pellets.
  • the function of this innovative burner is to heat the circulating flow to the temperature levels required for the process and have the NOx emission output as low as possible.
  • Another objective of this invention is to present a low NOx emission burner, which set includes the fuel gas collector manufactured in the shape of a circular ring and made, for example, from stainless steel or silicon carbide.
  • the fuel gas collector is equipped with a set of fins mounted in the inner part of the collector.
  • the fins present innovative special profile and are fixed to the collector so as to deflect the descending gas flow from the vertical movement with the addition of horizontal movement vector. This vector, together with the cylindrical shape of the descending channel, creates a rotating movement of the gases downstream the collector ring/fins set.
  • the collector further comprises a plurality of fuel gas discharge openings. These openings form groups aligned with each fin. Each group can comprise, for example, from four to six fuel gas discharge openings which discharge gas against the wall of each fin.
  • the fuel gas collector ring has at least one inlet, which is connected to the fuel gas supply system.
  • the burner set is inserted in the vertical passage of the furnace wherein the descending flow needs to be heated, for example from 900 to 1300 °C, before entering the iron ore pellet moving grate.
  • the fins deflect part of the descending flow and create the rotational flow effect in the vertical passage of the furnace.
  • the descending vertical passage is necessary to create this swirling effect and allows in this manner the quick mixing of the fuel gas with oxidant before the occurrence of the combustion reaction. Therefore, the definition of the insertion place of the burner in the vertical passage is essential to achieve the desired result.
  • the new method proposes that the fuel gas jets discharged from the collector ring mix predominantly first with the oxidant and next burn in the rotating descending flow current.
  • the uniform distribution of the fuel gas around the perimeter of the passage of the downcomer allows the rapid mixing of the fuel gas with the descending flow diluted oxygen.
  • the descending flow gases are comprised mainly of oxygen (O 2 ), nitrogen (N 2 ), carbon dioxide (CO 2 ) and water vapor. (H 2 O).
  • O 2 oxygen
  • N 2 nitrogen
  • CO 2 carbon dioxide
  • H 2 O water vapor.
  • the presence of these inert gases (CO 2 , N 2 and H 2 O) significantly reduces the adiabatic temperature of the combustion reaction. All these factors together can lead to a significant reduction in the NOx formation in the combustion zone.
  • the present patent of invention relates to a "LOW NOX EMISSION BURNER AND OPERATING METHOD FOR REDUCING NOX FORMATION APPLIED TO IRON ORE PELLET SINTERING AND/OR ENDURING METHOD", more precisely, it relates to an industrial combustion type burner (12) and process for pelletizing iron ore, and more exactly, to the iron ore pellet sintering and/or enduring furnaces.
  • said burner (12) is installed in the descending passage (14) of the furnace (FO) by means of the window (16), located on the upper portion of the descending passage (14). Said burner (12) elevates the temperature of the descending circulating flow (18) originating from the flue gas collector (20) to the required level before entering the moving grate (22) provided with iron ore pellets (22a).
  • the burner (12) is comprised of a circular or rectangular section fuel gas collector ring (24).
  • the outer diameter (D) of the ring (24) is smaller than the inner diameter (D') of the descending passage (14).
  • the collector ring (24) is equipped with fins (26) (see figures 2 , 3 and 4 ) on the inner circumference thereof, oblique, in ( ⁇ ) angulation relative to the horizontal transversal place of the collector, which allows deflecting the descending flow and introducing horizontal velocity components to the same.
  • Said ( ⁇ ) angulation promotes the speed vector to obtain tangential component and so that, in the cylindrical profile of the descending channel, there is generated the swirling or rotational effect.
  • the ( ⁇ ) deflection angle of the fin (26) can be from 30° to 60° relative to the horizontal transversal plane of the fuel gas collector ring (24). If the ( ⁇ ) angle is greater than 60°, the deflection and, in this manner, the rotational effect, will not be sufficiently intense to achieve the desired rapid mix of fuel gas with oxidant. On the other hand, if the ( ⁇ ) angle is less than 30°, the resistance to the descending flow (18) increases significantly resulting in less flow running along the fins (26) and more flow in the center of the descending channel (14).
  • the distance (K) between the fins (26), the length (L) of each fin (26) and number of fins (26) are determined to create the necessary descending flow rotating intensity (18) without significantly increasing the pressure loss through the burner (12) installed in the descending channel.
  • the determination of the three parameters (K), (L) and number of fins (26) depends on the diameter (D') and transversal area of the descending channel (14) wherein the burner (12) is installed.
  • the fuel gas collector ring (24) of the burner (12) is equipped with at least one inlet pipe (28) positioned orthogonally to the collector ring (24), which is connected to the fuel gas supply line.
  • the fuel gas is injected in the hot air current (18) through a plurality of openings (30) (see figure 5 ).
  • Said openings form aligned groups (32) and have the discharge thereof pointed in the direction of the wall of each aligned fin (26).
  • Each group (32) can be formed by two up to eight openings (30), in this case we present a model with five openings for fuel jet discharge (34) in each fin passage (26).
  • Part of the total descending flow (18) runs along the passage of the fin (26) mixing with the five fuel jets (34) and all together are deflected to create a rotating flow downstream the burner (12).
  • Each fin (26) (see figures 4 and 6 ) is constructed as an 'L' shaped profile, with flap (26a) forming ( ⁇ ) angle 90° (see figure 6 ). This varies preferably between 45°and 90°. If the ( ⁇ ) angle exceeds 90°, the fuel gas jets (34) can partly escape the passage of the fin (26) and reduce the efficiency of the mixture. On the other hand, if this ( ⁇ ) angle is less than 45°, the fuel gas jets (34) can create unecessary pressure fluctuations and possibly vibration of the burner (12).
  • the choice of the dimension (N) of the fin (26) depends on the diameter (D') and area of the descending flow (14), wherein the burner (12) is installed.
  • the ratio of the dimensions (M)/(N) of each fin (26) is preferably between 0,25 and 0,5, if less than 0,25, the fuel gas jets (34) can escape from the passage of the fin (26), if greater than 0,5 the fin (26) will be heavier without any additional benefit to the burner.
  • each fin (26) can be cast so as to (see figure 7 ) deflect the descending flow (18) more horizontally, and, by doing this, promote higher rotation degree inside the cylindrical descending channel downstream of the burner (12).
  • the cylindrical descending channel (14) must be considered as being part of the burner (12). Part of the descending flow (18) deflected by the fins (26) is pre-mixed with the fuel gas and acquires rotating movement (42) along the cylindrical surface of the descending channel (14). In this region, with length (L) equal to approximately a diameter (D') of the channel, the current is burned.
  • the fuel gas is evenly distributed around the circumference (46) of this channel, the mixing occurs quickly with oxygen diluted in the inert gases, and, as a result, the temperature peaks reduce significantly, and the combustion reaction produces a very low NOx emission when compared to the prior art.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacture And Refinement Of Metals (AREA)
EP21956274.1A 2021-09-09 2021-09-09 Brûleur à faibles émissions de nox et procédé de fonctionnement pour réduire la formation de nox appliqué dans le procédé de frittage et/ou de durcissement de boulettes de minerai de fer Pending EP4400766A4 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/BR2021/050386 WO2023035050A1 (fr) 2021-09-09 2021-09-09 Brûleur à faibles émissions de nox et procédé de fonctionnement pour réduire la formation de nox appliqué dans le procédé de frittage et/ou de durcissement de boulettes de minerai de fer

Publications (2)

Publication Number Publication Date
EP4400766A1 true EP4400766A1 (fr) 2024-07-17
EP4400766A4 EP4400766A4 (fr) 2025-04-30

Family

ID=85506019

Family Applications (1)

Application Number Title Priority Date Filing Date
EP21956274.1A Pending EP4400766A4 (fr) 2021-09-09 2021-09-09 Brûleur à faibles émissions de nox et procédé de fonctionnement pour réduire la formation de nox appliqué dans le procédé de frittage et/ou de durcissement de boulettes de minerai de fer

Country Status (4)

Country Link
US (1) US20240159393A1 (fr)
EP (1) EP4400766A4 (fr)
AU (1) AU2021463384A1 (fr)
WO (1) WO2023035050A1 (fr)

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JP2010024477A (ja) 2008-07-16 2010-02-04 Kobe Steel Ltd 鉄鉱石ペレットの製造方法
JP5458860B2 (ja) 2009-12-15 2014-04-02 株式会社ニコン 撮像装置
JP5789883B2 (ja) 2011-12-05 2015-10-07 Ｐｒｉｍｅｔａｌｓ Ｔｅｃｈｎｏｌｏｇｉｅｓ Ｊａｐａｎ株式会社 部分還元鉄製造方法および部分還元鉄製造装置
KR102010490B1 (ko) 2011-12-21 2019-08-13 켄터키-테네시 클레이 컴퍼니 응집, 침적, 부식과 같은 문제점들을 회피하고 배출들을 감소시키기 위한 미네랄 첨가제 배합 조성물들 및 연소실들의 작동 방법들
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CN213237516U (zh) * 2020-09-24 2021-05-18 徐州亚华同创节能环保科技有限公司 一种耐高温放散燃烧器
CN112361335B (zh) * 2020-11-27 2024-07-26 华侨大学 一种基于多区域燃烧的燃烧器

Also Published As

Publication number Publication date
WO2023035050A1 (fr) 2023-03-16
US20240159393A1 (en) 2024-05-16
AU2021463384A1 (en) 2023-09-28
EP4400766A4 (fr) 2025-04-30

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