EP0238907B1 - Low excess air tangential firing system - Google Patents

Low excess air tangential firing system Download PDF

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Publication number
EP0238907B1
EP0238907B1 EP87103150A EP87103150A EP0238907B1 EP 0238907 B1 EP0238907 B1 EP 0238907B1 EP 87103150 A EP87103150 A EP 87103150A EP 87103150 A EP87103150 A EP 87103150A EP 0238907 B1 EP0238907 B1 EP 0238907B1
Authority
EP
European Patent Office
Prior art keywords
air
furnace
coal
level
primary
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP87103150A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0238907A3 (en
EP0238907A2 (en
Inventor
Joseph David Bianca
David Kenneth Anderson
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.)
Combustion Engineering Inc
Original Assignee
Combustion Engineering Inc
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Filing date
Publication date
Application filed by Combustion Engineering Inc filed Critical Combustion Engineering Inc
Publication of EP0238907A2 publication Critical patent/EP0238907A2/en
Publication of EP0238907A3 publication Critical patent/EP0238907A3/en
Application granted granted Critical
Publication of EP0238907B1 publication Critical patent/EP0238907B1/en
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Classifications

    • 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 
    • F23C5/00—Disposition of burners with respect to the combustion chamber or to one another; Mounting of burners in combustion apparatus
    • F23C5/08—Disposition of burners
    • F23C5/32—Disposition of burners to obtain rotating flames, i.e. flames moving helically or spirally
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D1/00—Burners for combustion of pulverulent fuel

Definitions

  • Pulverized coal has been successfully burned in suspension in furnaces by tangential firing methods for a long time.
  • the technique involves introducing the coal and air into a furnace from the four corners thereof so that it is directed tangent to an imaginary circle in the center of the furnace.
  • This type of firing has many advantages, among them being good mixing of the fuel and air, stable flame conditions, and long residence time of the combustion gases in the furnace. In recent times, it has become important to minimize air pollution as much as possible. Thus, some proposed changes have been made to the standard tangential firing method.
  • the burners at one level are arranged to discharge in a direction around the longitudinal axis of the furnace chamber opposite that in which the burners at an adjacent level discharge.
  • the unidirectional flow is destroyed shortly after ignition, being resolved into a large number of small eddies.
  • the fuel burns more quickly and the maximum rate of firing of the furnace chamber may be increased.
  • a furnace in which pulverized coal is burned in suspension with good mixing of the coal and air.
  • all of the advantages previously associated with tangentially fired furnaces are obtained, by having a swirling, rotating, fire ball in the furnace.
  • the walls are protected by a blanket of air, reducing slagging thereof. This is accomplished by introducing coal and primary air into the furnace tangentially at a first level, introducing auxiliary air in an amount at least twice that of the primary air into the furnace tangentially at a second level directly above the first level, but in a direction opposite to that of the primary air, with there being a plurality of such first and second levels, one above the other.
  • the ultimate swirl within the furnace will be in the direction of the auxiliary air introduction. Because of this, the fuel, which is introduced in a direction counter to the swirl of the furnace, is forced after entering the unit, to change direction to that of the overall furnace gases. Tremendous turbulent mixing between the fuel and air is thus created in this process. This increased mixing reduces the need for high levels of excess air within the furnace. This increased mixing also results in enhanced carbon conversion which improves the units over all heat release rate while at the same time reducing upper furnace slagging and fouling.
  • the auxiliary air is directed at a circle of larger diameter than that of the fuel, thus forming a layer of air adjacent the walls.
  • overfire air consisting essentially of all of the excess air supplied to the furnace, is introduced into the furnace at a level considerably above all of the primary and auxiliary air introduction levels, with the overfire air being directed tangentially to an imaginary circle, and in a direction opposite to that of the auxiliary air.
  • a coal-fired furnace 10 having a plurality of levels of burners 12 therein with each level having a burner mounted in each of the four corners thereof. Air is supplied to the burners from fan 16 through ducts 18 and 20. Air is also supplied to pulverizer 22 through duct 24. Pulverized coal is transported to the burners in an air stream through ducts 26 and 28. There are separate air and fuel ducts leading to each individual burner, with separate valves and controls (not shown) also, so that each burner can be independently controlled. The combustion gases swirling upwardly in the furnace give up heat to the fluid passing through the tubes 30 lining all four of the furnace walls, before exiting the furnace through horizontal pass 32, leading to rear gas pass 34. Both the furnace and the rear pass contain other heat exchanger surface (not shown), for generating and superheating steam, as well known in the art.
  • Pulverized coal generally ground to a flour-like consistency, is carried to each burner in a stream of air from the pulverizer mill 22.
  • This air that carried the coal is generally referred to as the primary air.
  • more air generally designated as secondary air, is through nozzles 36 introduced directly above and below the fuel-through nozzles 38. These nozzles 36 are tiltable along with the nozzles 38 through which the coal and primary air are introduced. This air is necessary for maintaining initial ignition and stable combustion conditions.
  • the primary and secondary air constitutes about 20-30% of the total air required for complete or stoichiometric combustion of the coal.
  • each secondary air nozzle 36 positioned above and below each secondary air nozzle 36 are auxiliary, or tertiary air nozzles 40.
  • the remainder of the air necessary for complete combustion, or stoichiometric conditions, is introduced through these nozzles 40.
  • FIGs 3 and 4 the manner in which the coal and primary air, the secondary air, and the auxiliary air, is tangentially introduced into the furnace, is shown.
  • the coal and primary air along with the secondary air are introduced into the furnace tangential to an imaginary circle 42 in the central portion of the furnace.
  • the auxiliary air is introduced into the furnace tangential to an imaginary circle 44, at locations directly above and below the fire ball 42.
  • the auxiliary air is introduced into the furnace rotating in a direction reverse, or opposite to the direction of rotation of the primary air and fuel. The result of this is a mixing and combustion efficiency much better than that realized with the usual tangentially fired furnace. This permits the use of less excess air in the furnace than previously required.
  • the ultimate fire ball rising in the furnace rotates in a direction the same as that of the auxiliary air, since the mass introduced in this direction is several times that introduced in the opposite direction.
  • the velocity of the auxiliary air is comparable to that of the primary and secondary air.
  • the auxiliary air is introduced at a 5-15° angle to the same vertical centerline of the furnace but opposite in direction. In this manner, the fuel and air are introducing swirl within the furnace in opposite directions. As stated previously, however, because of the greater mass and velocity of the auxiliary air, the ultimate overall swirl within the unit will be in the direction of the auxiliary air introduction.
  • the top wall of the furnace is approximately 30.48 meters (100 feet) above the top burner elevation, and the excess, or overfire, air is introduced about 18.29 meters (60 feet) above the top burner elevations.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combustion Of Fluid Fuel (AREA)
  • Manufacture Of Iron (AREA)
EP87103150A 1986-03-24 1987-03-05 Low excess air tangential firing system Expired - Lifetime EP0238907B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US84341986A 1986-03-24 1986-03-24
US843419 1986-03-24

Publications (3)

Publication Number Publication Date
EP0238907A2 EP0238907A2 (en) 1987-09-30
EP0238907A3 EP0238907A3 (en) 1988-11-09
EP0238907B1 true EP0238907B1 (en) 1991-07-24

Family

ID=25289919

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87103150A Expired - Lifetime EP0238907B1 (en) 1986-03-24 1987-03-05 Low excess air tangential firing system

Country Status (11)

Country Link
EP (1) EP0238907B1 (ja)
JP (1) JPS62233610A (ja)
KR (1) KR900006241B1 (ja)
CN (1) CN1005589B (ja)
AU (1) AU583717B2 (ja)
CA (1) CA1273248A (ja)
DE (1) DE3771537D1 (ja)
DK (1) DK147587A (ja)
ES (1) ES2025077B3 (ja)
IN (1) IN168173B (ja)
ZA (1) ZA872065B (ja)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3920798A1 (de) * 1989-06-24 1991-01-10 Balcke Duerr Ag Vorrichtung zur verbrennung von brennstoffen in einer brennkammer
JP2540636B2 (ja) * 1989-11-20 1996-10-09 三菱重工業株式会社 ボイラ
FR2663723B1 (fr) * 1990-06-20 1995-07-28 Air Liquide Procede et installation de fusion d'une charge en four.
DE19749431C1 (de) * 1997-11-08 1999-03-18 Steinmueller Gmbh L & C Verfahren zum Verbrennen von Brennstoffstaub in einer Tangentialfeuerung und Tangentialfeuerung zur Durchführung des Verfahrens
US20040221777A1 (en) * 2003-05-09 2004-11-11 Alstom (Switzerland) Ltd High-set separated overfire air system for pulverized coal fired boilers
CN100427824C (zh) * 2005-12-23 2008-10-22 浙江大学 邻角错位直流燃烧器
CN100451447C (zh) * 2006-11-30 2009-01-14 上海交通大学 无烟煤燃烧方法
CN100491821C (zh) * 2007-06-28 2009-05-27 上海交通大学 浓相反吹多重分级NOx燃烧方法
CN101852429A (zh) * 2010-06-29 2010-10-06 哈尔滨工业大学 一种墙式布置带侧二次风的直流煤粉燃烧装置
CN102032555A (zh) * 2010-12-07 2011-04-27 上海锅炉厂有限公司 一种锅炉燃烧装置
JP6087793B2 (ja) * 2013-11-15 2017-03-01 三菱日立パワーシステムズ株式会社 ボイラ
JP6246709B2 (ja) * 2014-12-19 2017-12-13 三菱日立パワーシステムズ株式会社 燃焼バーナ及びボイラ
CN104848544B (zh) * 2015-04-21 2017-12-26 武汉轻工大学 一种旋浮燃烧的液体介质导热炉
CN111999429B (zh) * 2020-09-01 2022-06-21 中北大学 高温火球准静态模拟装置

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB697840A (en) * 1951-04-12 1953-09-30 Babcock & Wilcox Ltd Improvements in or relating to pulverised fuel furnaces
US4438709A (en) * 1982-09-27 1984-03-27 Combustion Engineering, Inc. System and method for firing coal having a significant mineral content
US4501204A (en) * 1984-05-21 1985-02-26 Combustion Engineering, Inc. Overfire air admission with varying momentum air streams
DE3531571A1 (de) * 1985-09-04 1987-03-05 Steinmueller Gmbh L & C Verfahren zum verfeuern von brennstoffen unter reduzierung der stickoxidbelastung und feuerung zur durchfuehrung des verfahrens

Also Published As

Publication number Publication date
CN1005589B (zh) 1989-10-25
ZA872065B (en) 1987-11-25
JPH0429926B2 (ja) 1992-05-20
CA1273248A (en) 1990-08-28
DE3771537D1 (de) 1991-08-29
DK147587D0 (da) 1987-03-23
ES2025077B3 (es) 1992-03-16
AU7050387A (en) 1987-10-01
AU583717B2 (en) 1989-05-04
KR870009175A (ko) 1987-10-24
CN87102205A (zh) 1987-11-18
EP0238907A3 (en) 1988-11-09
KR900006241B1 (ko) 1990-08-27
JPS62233610A (ja) 1987-10-14
EP0238907A2 (en) 1987-09-30
DK147587A (da) 1987-09-25
IN168173B (ja) 1991-02-16

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