JPH049511A - Pulverized coal firing method, pulverized coal boiler and pulverized coal burner - Google Patents
Pulverized coal firing method, pulverized coal boiler and pulverized coal burnerInfo
- Publication number
- JPH049511A JPH049511A JP11250990A JP11250990A JPH049511A JP H049511 A JPH049511 A JP H049511A JP 11250990 A JP11250990 A JP 11250990A JP 11250990 A JP11250990 A JP 11250990A JP H049511 A JPH049511 A JP H049511A
- Authority
- JP
- Japan
- Prior art keywords
- pulverized coal
- air
- flow path
- combustion
- burner
- 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
- 239000003245 coal Substances 0.000 title claims abstract description 183
- 238000000034 method Methods 0.000 title claims description 13
- 238000010304 firing Methods 0.000 title 1
- 238000002485 combustion reaction Methods 0.000 claims abstract description 118
- 239000000203 mixture Substances 0.000 claims abstract description 19
- 239000002245 particle Substances 0.000 claims abstract description 14
- 230000008859 change Effects 0.000 claims description 21
- 238000009841 combustion method Methods 0.000 claims description 14
- 239000010419 fine particle Substances 0.000 claims description 10
- 239000007789 gas Substances 0.000 abstract description 12
- 239000001301 oxygen Substances 0.000 abstract description 11
- 229910052760 oxygen Inorganic materials 0.000 abstract description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 9
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 57
- 239000000446 fuel Substances 0.000 description 17
- 230000000694 effects Effects 0.000 description 11
- 238000002156 mixing Methods 0.000 description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 230000007423 decrease Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 6
- 238000006722 reduction reaction Methods 0.000 description 6
- 238000002474 experimental method Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 230000003247 decreasing effect Effects 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 229910017464 nitrogen compound Inorganic materials 0.000 description 3
- 150000002830 nitrogen compounds Chemical class 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 239000011261 inert gas Substances 0.000 description 2
- 239000011859 microparticle Substances 0.000 description 2
- 238000011017 operating method Methods 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 229910000906 Bronze Inorganic materials 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 239000010974 bronze Substances 0.000 description 1
- 239000003610 charcoal Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Landscapes
- Regulation And Control Of Combustion (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は微粉炭燃焼装置に係り、特に負荷変動に対応し
やすく、シかも微粉炭火炎内でＮＯｘを低減し、燃焼性
を向上するのに好適な微粉炭燃焼法と微粉炭バーナおよ
び微粉炭ボイラに関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pulverized coal combustion device, which is particularly adaptable to load fluctuations, and is capable of reducing NOx in a pulverized coal flame and improving combustibility. The present invention relates to a pulverized coal combustion method, a pulverized coal burner, and a pulverized coal boiler suitable for.
微粉炭燃焼技術は産業用、工業用ボイラに適用され、既
に実用化されている技術である。Pulverized coal combustion technology is applied to industrial boilers and is already in practical use.
そして１石炭火力は中間負荷運用であり、運用性の拡大
をはかる計画があるため、ターンダウン比をより大きく
とれる微粉炭燃焼法および微粉炭バーナが要求される。1 Coal-fired power plants operate under intermediate loads, and since there are plans to expand operability, a pulverized coal combustion method and pulverized coal burner that can achieve a larger turndown ratio are required.
また、微粉炭ボイラはボイラ容量に応じてバーナ本数が
決定され、複数個の微粉炭バーナが火炉壁に配置されて
、ボイラ負荷１００％の場合には全バーナに微粉炭が供
給され、微粉炭の燃焼が実施される。一方、ボイラ負荷
を減少させるときには、特定のバーナへの微粉炭の供給
を停止し、使用するバーナ本数を減らして微粉炭燃焼量
を減少させ、負荷変動に対処するか、あるいは各バーナ
に供給する微粉炭量および燃焼用空気量を減少させ、負
荷変動に対処するボイラの運転方法が採られている。In addition, the number of burners in a pulverized coal boiler is determined according to the boiler capacity, and multiple pulverized coal burners are arranged on the furnace wall, and when the boiler load is 100%, pulverized coal is supplied to all burners, and the pulverized coal is combustion is carried out. On the other hand, when reducing the boiler load, either stop the supply of pulverized coal to a specific burner, reduce the number of burners used to reduce the amount of pulverized coal burned, deal with load fluctuations, or supply it to each burner. Boiler operating methods have been adopted that reduce the amount of pulverized coal and combustion air to cope with load fluctuations.
しかして、前記のように負荷が変動した場合であっても
、火炎が安定に形成でき、燃焼状態を安定に維持できる
ことがボイラ運転上不可欠である。Therefore, even when the load fluctuates as described above, it is essential for boiler operation to be able to form a flame stably and maintain a stable combustion state.
また、迅速に負荷変動指令に対処できることも重要であ
る。It is also important to be able to quickly respond to load fluctuation commands.
これに対し、前者、すなわち使用バーナ本数を減らすボ
イラ運転法は、使用バーナへの微粉炭および燃焼用空気
の供給量が変化しないので、個個のバーナの燃焼状態に
大きな変化は生じない。On the other hand, in the former boiler operation method in which the number of burners used is reduced, the amount of pulverized coal and combustion air supplied to the burners used does not change, so there is no large change in the combustion state of each burner.
しかし、このボイラ運転法によれば、微粉炭を停止した
バーナにもバーナの焼損防止のために燃焼用空気の一部
が冷却用に供給される。そのため、火炉内の流れおよび
温度分布が変化し、ボイラ内での燃焼状態は変化する。However, according to this boiler operating method, a portion of the combustion air is supplied for cooling even to the burner in which pulverized coal has been stopped in order to prevent burning out of the burner. Therefore, the flow and temperature distribution within the furnace change, and the combustion state within the boiler changes.
また１個々バーナの微粉炭燃焼量が決められているため
、負荷変化率を連続的に変化するのは困難となる６
一方、後者、すなわちバーナ全数に微粉炭および燃焼用
空気を供給し、微粉炭および燃焼用空気の供給量を制御
するボイラ運転法は、連続的に負荷変化率を変えること
ができる。In addition, since the amount of pulverized coal burned per individual burner is determined, it is difficult to continuously change the load change rate6. The boiler operation method that controls the supply amount of coal and combustion air can continuously change the load change rate.
しかし、このボイラ運転法によれば、バーナの燃焼状態
が変化し、低負荷時に微粉炭供給量が減少するため１着
火、保炎性が低下し、不安定な火炎になりやすい、そし
て、このような微粉炭の着火、保炎性は、微粉炭の濃度
のほかに、微粉炭粒子の粒径、微粉炭が噴出された直後
の燃料と燃焼用空気との混合過程、および火炎内の空気
比等。However, according to this boiler operation method, the combustion state of the burner changes and the amount of pulverized coal supplied decreases at low loads, resulting in a decrease in ignition and flame stability, which tends to result in an unstable flame. The ignition and flame stability of pulverized coal depend not only on the concentration of pulverized coal, but also on the particle size of pulverized coal particles, the mixing process of fuel and combustion air immediately after pulverized coal is ejected, and the air in the flame. ratio etc.
多くの因子により影響を受ける。また、これら燃料と燃
焼用空気との混合過程、および火炎内の空気比分布は、
微粉炭流の噴出速度と燃焼用空気の噴出速度、および燃
焼用空気の旋回強度等により影響される。Influenced by many factors. In addition, the mixing process of these fuels and combustion air and the air ratio distribution within the flame are as follows:
It is influenced by the ejection speed of the pulverized coal flow, the ejection speed of the combustion air, the swirling strength of the combustion air, etc.
ところで、微粉炭はノイズ近傍で温度が高いほど、また
微細な粒子が多いほど着火しやすく、さらに着火が起こ
る空気比条件を形成する必要があり、したがって如何に
ノズル近傍にこの着火しやすい雰囲気を形成し、微細な
粒子を集めるかが重要な鍵となる。By the way, the higher the temperature of pulverized coal is near the noise, and the more fine particles there are, the easier it is to ignite, and it is necessary to create an air ratio condition that will cause ignition. The key is how to form and collect fine particles.
一方、環境規制は年々厳しくなり、燃焼装置から排出さ
れる窒素酸化物（ＮＯｘ）の低減も要求される８石炭燃
焼にともなって生成されるＮＯｘの大半は、燃料中の窒
素分が酸化して生成される。On the other hand, environmental regulations are becoming stricter year by year, and reductions in nitrogen oxides (NOx) emitted from combustion equipment are required.8 Most of the NOx generated during coal combustion is caused by the oxidation of nitrogen in the fuel. generated.
いわゆるフューエルＮＯｘであり、またこのフューエル
ＮＯｘは、揮発成分中の窒素分からＮＯｘと、チャー中
の窒素分からのＮＯｘとに分けられ。This is so-called fuel NOx, and this fuel NOx is divided into NOx from nitrogen in volatile components and NOx from nitrogen in char.
石炭の燃焼では、このフューエルＮＯｘを対象とする低
ＮＯｘ燃焼技術が望まれる。In coal combustion, a low NOx combustion technology that targets this fuel NOx is desired.
そして、前記した揮発性窒素分は、燃焼初期過程および
酸素不足の燃焼領域おいて、ＮＯｘの他にＮＨａ、ＨＣ
Ｎ等の化合物になることが知られている。また、これら
の窒素化合物は、酸素と反応してＮＯｘになるほかに、
発生したＮＯｘと反応してＮＯｘをＮ２に分解する還元
剤にもなる。この窒素化合物によるＮＯｘの還元反応は
、ＮＯｘとの共存系において、進行するものであり、Ｎ
Ｏｘが共存しない反応系では、大半の窒素化合物はＮＯ
ｘに酸化される。そして、前記還元反応は、燃焼のよう
な高温条件下では、低酸素雰囲気になるほど進行し易い
。したがって、微粉炭火炎内でＮＯｘを低減するには、
如何にこの低酸素雰囲気を形成させるかが技術的な鍵と
なる。In addition to NOx, the volatile nitrogen content mentioned above includes NHa, HC, etc. in the initial combustion process and in the oxygen-deficient combustion region.
It is known that it becomes a compound such as N. In addition to reacting with oxygen to become NOx, these nitrogen compounds also
It also acts as a reducing agent that reacts with generated NOx and decomposes it into N2. This reduction reaction of NOx by nitrogen compounds proceeds in a coexisting system with NOx, and N
In a reaction system where Ox does not coexist, most nitrogen compounds are NO
oxidized to x. The reduction reaction progresses more easily under high-temperature conditions such as combustion, as the atmosphere becomes lower in oxygen. Therefore, to reduce NOx in a pulverized coal flame,
The technical key is how to form this low-oxygen atmosphere.
ところで、これまで知られている微粉炭の着火性、保炎
性を向上させ、低酸素雰囲気を火炎内に形成させるため
の微粉炭燃焼法としては、たとえば特公平１−２２５２
６号公報に示されるように、二次空気流路形状を変える
ように駆動される部材を設けたノズルを有し、かつ、燃
料ノズルと燃焼用空気ノズルとの間に不活性ガスを投入
する燃焼法がある。By the way, as a pulverized coal combustion method for improving the ignitability and flame stability of pulverized coal and forming a low-oxygen atmosphere in the flame that has been known so far, for example, Japanese Patent Publication No. 1-2252
As shown in Publication No. 6, it has a nozzle equipped with a member that is driven to change the shape of the secondary air flow path, and inert gas is injected between the fuel nozzle and the combustion air nozzle. There is a combustion method.
また、「微粉炭バーナ」と題する技術が特開昭５６−４
４５０５号公報に、さらにｒ未燃分燃焼用空気供給装置
」と題する技術が特開昭５８−１１７９０５号公報に、
またさらに「微粉炭の炉内脱硝燃焼装置」と題する技術
が特開昭５９−２０５５０７号公報にそれぞれ記載され
ている。In addition, the technology entitled "Pulverized coal burner" was published in Japanese Patent Application Publication No. 56-4.
4505, and a technology entitled ``R Unburnt Combustion Air Supply Device'' is further published in JP-A-58-117905.
Furthermore, a technique entitled "In-furnace denitrification combustion apparatus for pulverized coal" is described in Japanese Patent Application Laid-Open No. 59-205507.
しかしながら、従来の微粉炭燃焼法うち、ボイラ負荷変
化指令に対して特定のバーナカットで対応する場合は、
連続的に負荷を変化せしめることはできず、また各バー
ナへの微粉炭および燃焼用空気供給量を制御する場合は
、連続的に負荷変化率は制御できても、低負荷時に微粉
炭の安定な着火、保炎ができない欠点を有する。However, in the conventional pulverized coal combustion method, when responding to a boiler load change command with a specific burner cut,
It is not possible to change the load continuously, and when controlling the amount of pulverized coal and combustion air supplied to each burner, even if the rate of change in load can be controlled continuously, it is difficult to stabilize the pulverized coal at low loads. It has the disadvantage of not being able to properly ignite or hold flame.
従来、微粉炭燃焼にバーナを使用した場合、微粉炭噴出
口より半径方向に離れた空気ノズルから二次空気の大半
が投入され、また不活性ガスが投入されるため、燃焼用
空気と燃料流との混合が遅れ、低空気比大炎内に酸素濃
度の低い領域の形成は容易であるが、混合の遅れる分燃
焼時間が長くなり、燃焼率が低下する。また、燃焼装置
が大型化する等の問題点があった。さらに、二次空気流
路の側に設けられた部材により１部材後流側に二次空気
の一部を巻き込み、渦流を形成して微粉炭の着火性向上
を目的としているが、高温ガスをノズル近傍に引き戻す
再循環流が形成されず、また微粉炭粒子のうち微細な粒
子をノズル近傍に集めることができないため、着火性の
大幅な向上は望めない、さらに、一般的には、負荷変動
時石炭供給量以外に、燃焼用空気流量も制御するが、燃
焼用空気量変動により燃料噴流と燃焼空気との混合過程
が影響され、微粉炭の着火性、保炎性が変わる。そして
、この微粉炭の着火、保炎性は微粉炭ノズル後流の渦流
だけで決定される現象ではなく。Conventionally, when a burner is used for pulverized coal combustion, most of the secondary air is injected from an air nozzle radially away from the pulverized coal injection port, and inert gas is also injected, so the combustion air and fuel flow are Although it is easy to form a region with low oxygen concentration in the low air ratio large flame, the combustion time becomes longer due to the delayed mixing, and the combustion rate decreases. Additionally, there were other problems such as the combustion device becoming larger. Furthermore, a part of the secondary air is drawn into the downstream side of one member by a member provided on the side of the secondary air flow path, and a vortex is formed to improve the ignitability of pulverized coal. Since a recirculation flow is not formed to pull the coal back to the vicinity of the nozzle, and fine particles among the pulverized coal particles cannot be collected near the nozzle, a significant improvement in ignitability cannot be expected.Furthermore, in general, load fluctuations In addition to the amount of coal supplied, the flow rate of combustion air is also controlled, but variations in the amount of combustion air affect the mixing process of the fuel jet and combustion air, changing the ignitability and flame stability of pulverized coal. The ignition and flame stability of pulverized coal are not determined solely by the vortex flow behind the pulverized coal nozzle.
燃焼用空気の噴出速度や旋回強度も影響するが。The jetting speed and swirling strength of the combustion air also have an effect.
従来この影響に対する配慮はなされていなかった。Conventionally, no consideration was given to this effect.
ところで、前記〔従来の技術〕の項に記述した先行技術
のうち、「未燃分燃焼用空量供給装置」と題する特開昭
５８−１１７９０５号公報には、炉内脱硝燃焼装置のア
フターエアノズル構造につき、空気流量に応じて空気噴
出位置を変え、空気噴射速度を変える旨記載されている
。By the way, among the prior art described in the above [Prior Art] section, Japanese Patent Application Laid-open No. 117905/1983 entitled "Air supply device for unburned matter combustion" describes an after-air nozzle for an in-furnace denitrification combustion device. Regarding the structure, it is stated that the air jetting position is changed according to the air flow rate, and the air jetting speed is changed.
しかしながら１本公知例は、炉内脱硝燃焼装置のアフタ
ーエアノズルに関するものであって、本発明で対象とす
る微粉炭バーナとは異なる。また。However, one known example relates to an after-air nozzle for an in-furnace denitrification combustion device, and is different from the pulverized coal burner targeted by the present invention. Also.
本発明においては、空気の噴出速度を変える手段として
、空気供給位置を変える手段を採用しているので、当然
その流れは変わる。したがって、微粉炭バーナにこの機
構を適用しても、その燃焼性は大きく変わり、本発明の
主旨とは相違する。In the present invention, since means for changing the air supply position is adopted as a means for changing the air ejection speed, the flow naturally changes. Therefore, even if this mechanism is applied to a pulverized coal burner, its combustibility will vary greatly, which is different from the gist of the present invention.
なお、前記〔従来の技術〕の項に記述した先行技術のう
ち、ｒ微粉炭バーナ」と題する特開昭５６−４４５０５
号公報、および「微粉炭の炉内脱硝燃焼装置」と題する
特開昭５９−２０５５０７号公報については後述する。Incidentally, among the prior art described in the above [Prior Art] section, Japanese Patent Application Laid-Open No. 56-44505 entitled "Pulverized Coal Burner"
JP-A No. 59-205507 entitled "In-Furnace Denitrification Combustion Apparatus for Pulverized Coal" will be described later.
本発明の目的は、負荷変動に対応しやすく、特に低負荷
時、微粉炭供給量が減少した状態でも微粉炭の着火、保
炎性を高め、また石炭の燃焼率を向上させ、低ＮＯｘ燃
焼が達成できる微粉炭燃焼法と微粉炭バーナおよび微粉
炭ボイラを提供することにある。The purpose of the present invention is to easily respond to load fluctuations, to improve the ignition and flame stability of pulverized coal even when the amount of pulverized coal supplied is reduced, especially at low loads, to improve the combustion rate of coal, and to achieve low NOx combustion. The object of the present invention is to provide a pulverized coal combustion method, a pulverized coal burner, and a pulverized coal boiler that can achieve this.
さらに詳細には、負荷変動時の微粉炭供給量が減少した
状態でも微粉炭の着火、保炎性を向上させ、石炭燃焼率
を向上させるために、微粉炭噴出直後の燃料と空気量と
を特定の着火に最適な割合に制御し、かつ着火性の高い
粒径の微粉炭をこの着火領域に集め、高温ガスをノズル
近傍に戻す強い再循環流を形成させ、二次空気との混合
を進めながら低空気比領域を火炎中心部に形成させ、燃
焼初期に発生したＮＯｘを火炎内で還元減少させたあと
に、三次空気と低空気比火炎とを混合して微粉炭の燃焼
を完結するようにした微粉炭燃焼法と微粉炭バーナおよ
び微粉炭ボイラを提供することにある。More specifically, in order to improve the ignition and flame stability of pulverized coal and the coal combustion rate even when the pulverized coal supply amount decreases during load fluctuations, the amount of fuel and air immediately after pulverized coal is ejected is adjusted. The ratio is controlled to be optimal for specific ignition, and pulverized coal with a highly ignitable particle size is collected in this ignition region, and a strong recirculation flow is formed to return the high-temperature gas to the vicinity of the nozzle, allowing it to mix with secondary air. As the combustion progresses, a low air ratio region is formed in the center of the flame, and after reducing and reducing NOx generated in the initial stage of combustion within the flame, tertiary air and the low air ratio flame are mixed to complete combustion of the pulverized coal. The object of the present invention is to provide a pulverized coal combustion method, a pulverized coal burner, and a pulverized coal boiler.
前記目的は、微粉炭の着火、燃焼性におよぼす微粉炭粒
径、火炎内の空気比、燃焼用空気の混合過程、および高
温再循環流の影響を明らかにするとともに、微粉炭の着
火、燃焼性と低空気比火炎の形成との関係を明らかにす
ることによって達成された。The purpose is to clarify the effects of pulverized coal particle size, air ratio in the flame, combustion air mixing process, and high-temperature recirculation flow on pulverized coal ignition and combustibility, and to This was achieved by elucidating the relationship between air temperature and the formation of low air ratio flames.
詳しくは、微粉炭を燃焼させ、微粉炭の着火領域、後流
の燃焼領域等、火炎内のガス組成、固体粒子を分析する
ことにより、微粉炭の着火、燃焼性の向上、および火炎
内でＮＯｘを低減するための最適ボイラの燃焼法と、そ
の燃焼法を達成するための微粉炭バーナおよび微粉炭ボ
イラを見い出した。In detail, by burning pulverized coal and analyzing the ignition area of pulverized coal, the combustion area of the wake, etc., the gas composition and solid particles in the flame, it is possible to ignite pulverized coal, improve combustibility, and improve the flammability of the pulverized coal. We have discovered an optimal boiler combustion method for reducing NOx, and a pulverized coal burner and pulverized coal boiler to achieve this combustion method.
前記目的を解決するための具体的手段は下記のとおりで
ある。Specific means for solving the above object are as follows.
すなわち、
（１）微粉炭と一次空気の混合気流路と二次空気流路と
の双方に流路断面を縮小する部材を設け、三次空気を混
合気流路から離れた位置より高流速の強い旋回流として
噴出することにより、部材後流側に強い再循環流を形成
せしめ、二九によって着火しやすい微小粒子（具体的に
は後述する２０ｔＬｍ以下の微小粒子）を循環流内に流
入しやすくし、２また高温のガスの一部を循環するよう
にした。In other words, (1) A member is provided in both the pulverized coal and primary air mixture flow path and the secondary air flow path to reduce the cross section of the flow path, and the tertiary air is swirled at a higher flow rate and more strongly than at a position away from the mixture flow path. By ejecting it as a flow, a strong recirculation flow is formed on the downstream side of the member, and microparticles that are easily ignited (specifically, microparticles of 20 tLm or less, which will be described later) can easily flow into the recirculation flow. , 2 Also, part of the high temperature gas was circulated.
（２）二次空気は、微粉炭噴出直後に当該微粉炭と二次
空気の一部とを混合し、かつ微粉炭の着火領域での空気
比を特定の値（具体的には０．４から０．６）に設定し
た。これは、０．４以下の空気比条件では微粉炭が着火
しないこと、また０、６ 以上になると、低空気比火炎
が保存されないことを実験により確認した結果にもとづ
く。(2) The secondary air is created by mixing the pulverized coal with a part of the secondary air immediately after the pulverized coal is ejected, and setting the air ratio in the ignition region of the pulverized coal to a specific value (specifically 0.4 to 0.6). This is based on the results of experiments confirming that pulverized coal does not ignite under air ratio conditions of 0.4 or less, and that low air ratio flames are not preserved when the air ratio is 0.6 or higher.
（３）微粉炭供給量が変化した場合、燃焼用空気量も変
化するため、燃焼用空気流速が低下しないよう三次空気
流路内に可動ブロックを配置し。(3) When the amount of pulverized coal supplied changes, the amount of combustion air also changes, so a movable block is placed in the tertiary air flow path to prevent the combustion air flow rate from decreasing.
燃焼用空気量が減少したときにはこの可動ブロックを三
次空気流路先端まで挿入し、流路断面積を縮小して少な
い空気流量でも高流速が得られ、前記（１）に記した高
温の循環流がバーナ面に戻るようにし、た。これは、三
次空気流速と高温循環流の形成、微粉炭粒子の着火性１
石炭燃焼率およびＮＯｘ排出量が密接に関係することを
実験により確認した結果にもとづく。When the amount of combustion air decreases, this movable block is inserted to the tip of the tertiary air flow path to reduce the cross-sectional area of the flow path and obtain a high flow velocity even with a small air flow rate. so that it returns to the burner side. This is due to the tertiary air flow velocity, the formation of high-temperature circulation flow, and the ignitability of pulverized coal particles.
This is based on the results of experiments confirming that coal combustion rate and NOx emissions are closely related.
しかして１本発明によれば、微粉炭および燃焼用空気流
量が変化しても、高温の循環流がバーナ面に戻るので５
微粉炭の着火性が向上し、火炎がバーナから離れること
がなく、微粉炭の安定な着火、保炎性が実施でき、燃焼
状態を安定に維持することができる。また、着火性が向
上したことにより低空気比火炎内の酸素の消費が早まり
、低酸素領域がバーナ近傍から形成されるため、微粉炭
火炎内で発生したＮＯｘが効率よく還元され、炉外に排
出されるＮＯｘの濃度は大幅に低減される。According to the present invention, even if the flow rates of pulverized coal and combustion air change, the high temperature circulating flow returns to the burner surface.
The ignitability of the pulverized coal is improved, the flame does not leave the burner, the pulverized coal can be ignited stably, the flame can be held stable, and the combustion state can be stably maintained. In addition, due to the improved ignitability, the consumption of oxygen in the low air ratio flame is accelerated, and a low oxygen region is formed from the vicinity of the burner, so NOx generated in the pulverized coal flame is efficiently reduced and released outside the furnace. The concentration of emitted NOx is significantly reduced.
さらに、この低空気比領域においても低空気比火炎と二
次空気との混合が進み、したがってこの低空気比領域で
の石炭燃焼率が高まり、三次空気と混合する位置が火炎
後流であっても、燃焼を完結するのに要する滞留時間を
増加させることがないため、燃焼装置は大きくならない
。Furthermore, even in this low air ratio region, mixing of the low air ratio flame and secondary air progresses, so the coal combustion rate increases in this low air ratio region, and the position where it mixes with the tertiary air is in the flame wake. However, since the residence time required to complete combustion does not increase, the combustion device does not become large.
Ｃ実施例〕
以下、本発明の実施例について、図を用いて詳細に説明
する。C Embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
〔実施例１〕
第１図は本発明に係る微粉炭バーナの一実施例を示す縦
断面図である。[Example 1] FIG. 1 is a longitudinal sectional view showing an example of a pulverized coal burner according to the present invention.
第１１図において、微粉炭と一次空気との混合気１を噴
出する混合気流路２の先端には、ａ合気流路２の断面積
を縮小するよう流れに直角に、また二次空気流路Ｓ側に
も突出した流路断面積縮小部材３が配置されている。混
合気流路２の先端位置は、下記する他の燃焼用空気流路
５，１０の先端より上流に位置するように配置されてい
る。混合気流路２の外側には二次空気４の流路５が、ま
た二次空気流路５の外側には、可動ブロック１３を内蔵
した三次空気流路１０が配置されている。二次空気流路
５の先端および三次空気流路１０の先端は、流路断面が
拡大された構造になっている。In FIG. 11, at the tip of the mixture flow path 2 that blows out the mixture 1 of pulverized coal and primary air, there is a secondary air flow path at right angles to the flow so as to reduce the cross-sectional area of the aikiki flow path 2. A flow passage cross-sectional area reducing member 3 that protrudes also on the S side is arranged. The tip of the air-fuel mixture passage 2 is located upstream of the tips of other combustion air passages 5 and 10, which will be described below. A flow path 5 for secondary air 4 is arranged outside the mixture flow path 2, and a tertiary air flow path 10 containing a movable block 13 is arranged outside the secondary air flow path 5. The tip of the secondary air flow path 5 and the tip of the tertiary air flow path 10 have a structure in which the cross section of the flow path is enlarged.
三次空気流路１０の先端は、二次空気流路５の先端より
後流側に位置させる。二次空気４および三次空気９は、
可動式の旋回羽根６．１１により旋回流として燃焼炉内
に噴出される。また、三次空気流、＠１０の流路断面積
は、燃焼条件、たとえば三次空気流量に応して、調節部
材１４により三次空気流路１０内に可動ブロック１３を
挿入し、三次空気流路１０内の断面積を変化させ、三次
空気流速を調整しながら噴出する。The tip of the tertiary air flow path 10 is located on the downstream side of the tip of the secondary air flow path 5. Secondary air 4 and tertiary air 9 are
It is blown into the combustion furnace as a swirling flow by the movable swirl vanes 6.11. In addition, the flow path cross-sectional area of the tertiary air flow @10 can be determined by inserting the movable block 13 into the tertiary air flow path 10 using the adjusting member 14, depending on the combustion conditions, for example, the tertiary air flow rate. The internal cross-sectional area is changed to eject air while adjusting the tertiary air flow velocity.
第２図は第１図の微粉炭バーナによる火炎形成の状況を
示し、次に＠２図を用いて本発明の詳細な説明する６
第２図において、微粉炭と一次空気との混合気１、二次
空気４および三次空気９が燃焼炉１６内に噴出されると
、火炎１７が形成される。燃焼炉１６は、一般には油燃
料火炎により予熱し、燃焼炉１６内の温度が充分高まっ
た時点で微粉炭を投入し、微粉炭と油燃料とを混焼した
のち、油燃料を遮断して微粉炭専焼に切り替える。燃料
と燃焼用空気とが供給されると、三次空気９が混合気流
路２より離れた位置から回転羽根１１により強い旋回流
として炉内に噴出されるため５部材３の後流側に再循環
流１５が形成される。この再循環流１５は、高温の火炎
１７の一部を巻き込み、部材３の近傍に高温のガスを引
き戻すため、部材３の後流側に高温領域が形成される。Figure 2 shows the state of flame formation by the pulverized coal burner of Figure 1, and next, the present invention will be explained in detail using Figure @2.6 In Figure 2, a mixture of pulverized coal and primary air 1 , secondary air 4 and tertiary air 9 are injected into the combustion furnace 16, a flame 17 is formed. The combustion furnace 16 is generally preheated by an oil-fuel flame, and when the temperature inside the combustion furnace 16 reaches a sufficient temperature, pulverized coal is introduced, the pulverized coal and oil fuel are co-fired, and then the oil fuel is shut off and the pulverized coal is mixed. Switch to charcoal-only grilling. When fuel and combustion air are supplied, the tertiary air 9 is ejected into the furnace as a strong swirling flow by the rotary vane 11 from a position away from the mixture flow path 2, so that it is recirculated to the downstream side of the 5 members 3. A stream 15 is formed. This recirculation flow 15 entrains a part of the high temperature flame 17 and draws the high temperature gas back to the vicinity of the member 3, so that a high temperature region is formed on the downstream side of the member 3.
また、混合気流路２から噴出された微粉炭粒子のうち、
微細な粒子はガスに同伴されやすいため、微小粒子がこ
の高温循環流に流入し、部材３の後流側に微小粒子の高
濃度領域が形成される。したがって、炉内１６に噴出さ
れた微粉炭粒子が急速に加熱され、着火が促進される。Furthermore, among the pulverized coal particles ejected from the mixture flow path 2,
Since fine particles are easily entrained in the gas, the fine particles flow into this high-temperature circulation flow, and a high concentration region of fine particles is formed on the downstream side of the member 3. Therefore, the pulverized coal particles ejected into the furnace 16 are rapidly heated and ignition is promoted.
また、高温循環流１５の形成により保炎性が一層高まり
、安定な火炎を形成することができる。さらに、二次空
気４の一部は再循環流１５に巻き込まれるため、部材３
の後流側には、微粉炭の着火に好適な空気比雰囲気が形
成される。三次空気９は強旋回流として燃焼炉内に投入
されるため、三次空気９の旋回力により火炎１７は広が
り、燃焼が進行した火炎１７の後流側で混合が促進され
、燃焼を完結することができる。In addition, the formation of the high-temperature circulating flow 15 further improves flame stability, making it possible to form a stable flame. Furthermore, a portion of the secondary air 4 is involved in the recirculation flow 15, so that the member 3
An air ratio atmosphere suitable for igniting the pulverized coal is formed on the downstream side of the pulverized coal. Since the tertiary air 9 is introduced into the combustion furnace as a strong swirling flow, the flame 17 spreads due to the swirling force of the tertiary air 9, promoting mixing on the downstream side of the flame 17 where combustion has progressed, and completing combustion. I can do it.
次に２本発明バーナの特徴および効果を実験結果にした
がって説明する。Next, the features and effects of the two burners of the present invention will be explained based on experimental results.
第３図〜第５図に本発明バーナと従来ヤ１バーナとの性
能比較を示す。3 to 5 show a performance comparison between the burner of the present invention and the conventional Y1 burner.
実験は石炭燃焼１２５ｋｇ／ｈ、燃焼炉の一辺が０．６
ｍ の矩形型断面を有する竪型燃焼炉を使用し、バーナ
を炉の上部に設置して、下降流の火炎を用いて行った。In the experiment, coal combustion was 125 kg/h, and one side of the combustion furnace was 0.6
A vertical combustion furnace with a rectangular cross section of m 2 was used, the burner was installed in the upper part of the furnace, and the flame was in a downward flow.
石炭は燃料比が２．０の海外炭を粉砕し、２００メツシ
ユ以下のものを７４％含有する微粉炭を使用した。The coal used was pulverized coal that had a fuel ratio of 2.0 and contained 74% of coal of 200 mesh or less.
第３図は本発明バーナと従来型バーナとを用いて、同操
作条件で微粉炭を燃焼させたときのバーナ面より０．１
ｍ 下流において、石炭粒子の重量濃度を開定し、特に
２０ｐｍ以下の微小粒子の重量濃度を比較したものであ
る。Figure 3 shows the results when pulverized coal is burned under the same operating conditions using the burner of the present invention and the conventional burner.
m Downstream, the weight concentration of coal particles was determined, and in particular, the weight concentration of fine particles of 20 pm or less was compared.
第３図において、ｍ軸は燃焼炉中心部（Ｘ ＝ Ｏ）か
ら炉壁までの距離を示し、縦軸は本発明バーナと従来型
バーナとを用いたときの２０μｍ以下の粒子の重量濃度
比を示す。なお、第３図中、火炎帯と記しであるのは、
微粉炭が着火し火炎を形成する領域である。In Fig. 3, the m-axis indicates the distance from the center of the combustion furnace (X = O) to the furnace wall, and the vertical axis indicates the weight concentration ratio of particles of 20 μm or less when using the burner of the present invention and the conventional burner. shows. In addition, in Figure 3, what is marked as a flame zone is
This is the area where pulverized coal ignites and forms a flame.
第３図から明らかなように、本発明バーナを用いると、
バーナ近傍のＸ＝１５ｏｎからＸ＝ｌＯＯ膿の領域で２
０μｍ以下の粒子量が多く、従来型バーナに比へてＸ＝
５０ｍ＋においては約１，８倍、Ｘ＝ １００ｗｍにお
いては約２．５倍微小粒子の濃度が高くなっており、し
たがって混合気流路２から噴出された微粉炭の着火領域
において、微粒子の増加による着火促進をはかることが
できる。As is clear from FIG. 3, when the burner of the present invention is used,
2 in the area of X = lOO pus from X = 15on near the burner
There is a large amount of particles of 0 μm or less, and compared to conventional burners, X =
The concentration of fine particles is approximately 1.8 times higher at 50 m+ and approximately 2.5 times higher at X = 100 wm. Therefore, in the ignition region of the pulverized coal ejected from the mixture flow path 2, ignition occurs due to an increase in fine particles. can be promoted.
第４図および第５図は、バーナ面から２．４ｍ下流まで
の燃焼炉中心軸上におけるガス温度と。Figures 4 and 5 show the gas temperature on the central axis of the combustion furnace up to 2.4 m downstream from the burner surface.
石炭の燃焼率とを比較した結果である。This is the result of a comparison with the combustion rate of coal.
第４図に示すように、燃焼炉内におけるガス温度は、バ
ーナより０．１ｍ下流において、本発明バーナでは１１
５０℃であるのに対し、従来型バーナでは９５０℃と低
い。バーナ面から０．７ｍ下流ではどちらも最高温度を
示すが、本発明バーナでは１４６０℃、従来型バーナで
は１３９０℃である。この結果から、本発明バーナを用
いるとバーナ近傍に高温領域が形成され、高温ガスの一
部が再循環流として混合気流路２の先端に設けた部材３
の後流側に戻るため１部材３の近傍の温度が高まり、微
粉炭の熱分解を促進して着火性を大幅に向上することが
できる。As shown in FIG. 4, the gas temperature in the combustion furnace is 11 m in the burner of the present invention at 0.1 m downstream from the burner.
While it is 50°C, it is as low as 950°C in a conventional burner. Both of them show the highest temperature 0.7 m downstream from the burner surface, which is 1460°C in the burner of the present invention and 1390°C in the conventional burner. From this result, when the burner of the present invention is used, a high-temperature region is formed near the burner, and a part of the high-temperature gas is recirculated to the member provided at the tip of the mixture flow path 2.
Since the pulverized coal returns to the wake side, the temperature near the first member 3 increases, promoting thermal decomposition of the pulverized coal and greatly improving ignitability.
第５図に示す燃焼率の変化も本発明バーナの特徴をよく
表している。The change in combustion rate shown in FIG. 5 also clearly represents the characteristics of the burner of the present invention.
第５図に示すように、着火性のよい本発明バーナでは、
バーナ面より０．１ｍ下流の位置において既に従来型バ
ーナに比へて燃焼率が高く、またバーナ面より０．４６
ｍ の位置では、その燃焼率は８０％と高い。０．４６
ｍ から１．１ｍの位置において１本発明バーナによる
燃焼率の増加は極めて少ないが、その理由は、この領域
では低空気比の低酸素濃度領域が保存されているためで
、この領域において、バーナ近傍で発生したＮＯｘの還
元反応が促進され、Ｎ Ｏｘの低減化をはかることがで
きる。１．１ｍ より下流は、中心部の低空比火炎と三
次空気との混合が進む領域であり、燃焼率が再び増加す
る。燃焼炉後流の燃焼反応が完結するバーナ面より２．
４ｍの位置で燃焼率を比較すると１本発明バーナは９９
．２ ％、従来型バーナは９８．５％ とその燃焼性に
顕著な差が現れる。また、この位置でのＮＯｘ４度は、
本発明バーナでは２００ｐｐｍ、従来型バーナでは２５
０ρｐｉでアＩＪ、本発明バーナを用いることによるＮ
Ｏｘ低減効果が大きい。As shown in FIG. 5, the burner of the present invention has good ignitability.
The combustion rate is already higher than that of conventional burners at a position 0.1 m downstream from the burner surface, and 0.46 m downstream from the burner surface.
At position m, the combustion rate is as high as 80%. 0.46
The increase in combustion rate by the burner of the present invention is extremely small at a position of 1.1 m from The reduction reaction of NOx generated in the vicinity is promoted, and it is possible to reduce NOx. Downstream from 1.1 m is a region where the low air ratio flame in the center and tertiary air are mixed, and the combustion rate increases again. 2. From the burner surface where the combustion reaction downstream of the combustion furnace is completed.
Comparing the combustion rate at a position of 4 m, the burner of the present invention has a combustion rate of 99.
．． 2%, and 98.5% for conventional burners, which shows a significant difference in combustibility. Also, NOx 4 degrees at this position is
200 ppm for the burner of the present invention and 25 ppm for the conventional burner.
A IJ at 0ρpi, N by using the burner of the present invention
Great Ox reduction effect.
欣に、二次空気流路１０内に可動ブロック１３を設けた
理由について、第６図および第７図を用いて説明する。The reason why the movable block 13 is provided in the secondary air flow path 10 will be explained with reference to FIGS. 6 and 7.
実験は第１図に示したバーナを用いておこない。The experiment was conducted using the burner shown in FIG.
可動ブロック１３の位置、および可動ブロック１３の厚
みを替えることにより三次空気流路１０の断面積を調整
し、三次空気流速を変化させた。By changing the position of the movable block 13 and the thickness of the movable block 13, the cross-sectional area of the tertiary air flow path 10 was adjusted, and the tertiary air flow velocity was changed.
また、燃料比が１．０ の国内炭を用い１石炭燃焼量は
２５ｋｇ／ｈ−燃焼炉出口酸素濃度は２％となる条件に
設定して実験を行った。なお、本実験結果はバーナ面よ
り２．４ｍ下流の位置で測定した結果である。Further, an experiment was conducted using domestic coal with a fuel ratio of 1.0, and setting conditions such that the combustion amount of one coal was 25 kg/h and the oxygen concentration at the outlet of the combustion furnace was 2%. Note that the experimental results were measured at a position 2.4 m downstream from the burner surface.
第６図および第７図から明らかなように、ＮＯｘＯｘ排
出濃度７燃炭燃焼率に、三次空気流速の影響が顕著に現
れている。また、第６図および第７図から９石炭燃焼率
が高く、かつ、ＮＯｘ排出濃度を低減できる三次空気流
速は２０〜５０ ｍ ／ ｓの範囲であり、三次空気の
噴出速度が微粉炭の着火性、燃焼性を大きく左右するこ
とがわかる。As is clear from FIGS. 6 and 7, the influence of the tertiary air flow velocity is noticeable on the NOxOx emission concentration 7 combustion rate. In addition, from Figures 6 and 7, the tertiary air flow velocity that provides a high coal combustion rate and can reduce the NOx emission concentration is in the range of 20 to 50 m/s, and the tertiary air jet velocity is high enough to ignite pulverized coal. It can be seen that it has a large effect on the properties and combustibility.
ところで、〔従来の技術〕の項に記した「微粉炭の炉内
脱硝燃焼装置」と題する特開昭５９−２０５５０７号公
報には、二段燃焼法を用いて炉内脱硝をおこなうとき、
最下段バーナと中段バ〜す（および上段バーナ）との構
造を異にし、最下段バーナで三次空気速度調整用のラッ
パ状体を摺動自在にする旨記載されている。By the way, in Japanese Patent Application Laid-open No. 59-205507 titled "In-furnace denitrification combustion apparatus for pulverized coal" described in the [Prior Art] section, when performing in-furnace denitration using a two-stage combustion method,
It is described that the structures of the lowest stage burner and the middle stage burner (and the upper stage burner) are different, and that a trumpet-shaped body for adjusting the tertiary air velocity is made slidable in the lowest stage burner.
しかしながら１本公知例では、第１に、炉内脱硝法につ
いて記されており、使用するバーナ構造が位置によって
異なるのに対し、本発明では同一バーナを用いている点
が相違する。However, in this known example, first, an in-furnace denitrification method is described, and the burner structure used differs depending on the position, whereas the present invention uses the same burner.
また５本公知例では負荷変動に対する記載、すなわち負
荷変動とバーナ操作条件、火炎形成状態が記されていな
い。Further, in the five known examples, there is no description of load fluctuations, that is, load fluctuations, burner operating conditions, and flame formation conditions.
さらに、本公知例では、最下段バーナについて三次空気
速度調整用のラッパ状体を摺動できる構造としているが
、この構造によれば下記の問題がある６
すなわち、第１０図（ａ）および（ｂ）のごとくラッパ
状体（イ）の位置を変えて三次空気の流速を調整する場
合、三次空気の流れ（フローパターン）が変わる。換言
すると、第１０図（ａ）および（ｂ）のバーナ構成では
、微粉炭流と三次空気との混合過程が異なるため、これ
によって着火。Furthermore, in this known example, the bottom stage burner has a structure in which the trumpet-like body for adjusting the tertiary air velocity can be slid, but this structure has the following problems6. When adjusting the flow velocity of the tertiary air by changing the position of the trumpet-shaped body (a) as in b), the flow (flow pattern) of the tertiary air changes. In other words, in the burner configurations shown in FIGS. 10(a) and 10(b), the mixing process of the pulverized coal flow and tertiary air is different, and this causes ignition.
保炎性が影響され、火炎は大きく変わる。Flame stability is affected and the flame changes greatly.
これに対し、本発明では、第１１図（ａ）および（ｂ）
に示すごとく、可動ブロック１３の位置が変わっても二
次空気、三次空気のフローパターンは変化せず、これに
より微粉炭の着火保炎性。In contrast, in the present invention, FIGS. 11(a) and (b)
As shown in the figure, even if the position of the movable block 13 changes, the flow patterns of the secondary air and tertiary air do not change, which improves the ignition flame stability of pulverized coal.
火炎の形が変わらない点で前掲特開昭５９−２０５５０
７号公報に記載の技術と大きく異なる。In that the shape of the flame does not change, the above-mentioned Japanese Patent Application Laid-Open No. 59-20550
This is significantly different from the technology described in Publication No. 7.
他方、〔従来の技術〕の項に記した「微粉炭バーナ」と
題する特開昭５６−４４５０５号公報には、第１２図に
示すように、二次スロート（ロ）を進退可能にして二次
空気流量の増減、さらには二次空気および三次空気の流
れを変える機能と効果とが記載されている。On the other hand, Japanese Patent Application Laid-Open No. 56-44505 entitled "Pulverized coal burner" described in the [Prior Art] section describes a secondary throat (b) that is movable in forward and backward directions, as shown in Fig. 12. Functions and effects for increasing and decreasing the secondary air flow rate, as well as changing the flow of secondary air and tertiary air, are described.
すなわち５本公知例のバーナ構造では、第１２図に示す
ごとく、三次空気ノズル（ハ）内に二次空気の噴出口を
位置させているため、二次空気が噴出されるとこれが即
座に三次空気の旋回流に引き寄せられ、バーナスロート
（ニ）の部分で二次空気と三次空気とが混合した状態で
炉内に噴出される。すなわち、二次空気および三次空気
は合流した状態で噴出されることになる。In other words, in the burner structure of the five known examples, as shown in FIG. Attracted by the swirling flow of air, secondary air and tertiary air are mixed and ejected into the furnace at the burner throat (d). That is, the secondary air and the tertiary air are ejected in a merged state.
そして、本公知例では、（二次空気十三次空気）は一定
と見なされ、二次空気流量を増減するとき三次空気流量
も増減し、両者が増減しても結果的には二次空気および
三次空気の総量が変わらないため、バーナスロートから
の噴出速度は変化しないと見なすことができる。In this known example, (secondary air, 13th air) is considered to be constant, and when the secondary air flow rate is increased or decreased, the tertiary air flow rate also increases or decreases, and even if both of them increase or decrease, the secondary air Since the total amount of tertiary air and tertiary air does not change, it can be assumed that the ejection velocity from the burner throat does not change.
しかし、本公知例においては、三次空気のみ旋回させ、
二次空気は旋回させていないので、その両者の流量配分
が変わると、旋回流の強さが変わる（すなわち、旋回流
の流れが変わる）。However, in this known example, only tertiary air is swirled,
Since the secondary air is not swirled, if the flow rate distribution between the two changes, the strength of the swirling flow changes (that is, the flow of the swirling flow changes).
また、前記に関連して、三次空気を減少させるときには
、二次スロート（ロ）の先端を保炎器（ホ）側に近づけ
、二次空気流路を縮小して行うと見なせるが、このとき
本公知例のバーナでは、三次空気流路が小さくなり、ま
た二次空気流量が減った分三次空気流量が増加するので
、三次空気流速がより速くなる。なお、これとは反対に
、二次空気を増加するときには、三次空気流速が大幅に
減少する。In addition, in relation to the above, when reducing the tertiary air, it can be considered that the tip of the secondary throat (b) is brought closer to the flame stabilizer (e) side and the secondary air flow path is reduced. In the burner of this known example, the tertiary air flow path becomes smaller, and the tertiary air flow rate increases by the amount corresponding to the decrease in the secondary air flow rate, so that the tertiary air flow rate becomes faster. Note that, on the contrary, when increasing the amount of secondary air, the tertiary air flow rate is significantly reduced.
以上のことから１本公知例では、二次スロートを進退さ
せると、二次空気流速および三次空気流速、さらには三
次空気の旋回強度が変化してしまうため、その変化にと
もない、燃焼状態が変わる。From the above, in this known example, when the secondary throat is moved back and forth, the secondary air flow velocity and tertiary air flow velocity, as well as the swirling strength of the tertiary air, change, so the combustion state changes with these changes. .
これに対し、本発明は、前記公知例とは別に。On the other hand, the present invention is different from the above-mentioned known examples.
二次流路と三次流路とを離して三次空気の噴出速度を制
御し、旋回強度を維持して各空気流量が変わってもフロ
ーパターンを変えないように制御するものであって、前
掲特開昭５６−４４５０５号公報に記載の技術とは異な
る。The secondary flow path and the tertiary flow path are separated from each other to control the ejection speed of the tertiary air, and the swirling strength is maintained so that the flow pattern does not change even if each air flow rate changes. This is different from the technology described in JP-A-56-44505.
Ｃ実施例２〕
第８図は第１図に示す微粉炭バーナを微粉炭ボイラに適
用した場合の一実施例を示す炉内構成説明図である６
なお、第８図には、微粉炭バーナ１９，２０を火炉壁に
対向させて配置する構造の微粉炭ボイラ１８を一例とし
て示す。C Embodiment 2] Figure 8 is an explanatory diagram of the furnace internal configuration showing an example in which the pulverized coal burner shown in Figure 1 is applied to a pulverized coal boiler6. A pulverized coal boiler 18 having a structure in which 19 and 20 are disposed facing the furnace wall is shown as an example.
第８図において、火炉壁に配置された複数の微粉炭バー
ナ１９．２０は、石炭粉砕機（図示せず）から空気によ
り搬送され、混合気１として１分配器２３〜２５を介し
て各バーナ１９，２０に供給される。燃焼用空気は、ボ
イラ出口に設けられた熱交換器２９によって昇温された
後、ファン３０によりダンパ３１，３２でその流量が調
整され。In FIG. 8, a plurality of pulverized coal burners 19, 20 arranged on the furnace wall are conveyed by air from a coal crusher (not shown), and a mixture 1 is sent to each burner through distributors 23 to 25. 19 and 20. Combustion air is heated by a heat exchanger 29 provided at the boiler outlet, and then its flow rate is adjusted by dampers 31 and 32 by a fan 30.
ウィンドボックス２２に導入された後、各バーナ１９．
２０に供給され、燃焼炉内１６に噴出される。また、Ｗ
１粉炭搬送系統には微粉炭量検出器２６が配置され、ウ
ィンドボックス２２には、ウィンドボックス２２内の圧
力を検出する検出器２７．２８が配置されている。圧力
検出器２７゜２８は、ウィンドボックス２２に供給され
る空気量と圧力との関係を把握しておくことにより、空
気量を圧力変化から検出するためのものである。After being introduced into the wind box 22, each burner 19.
20 and is injected into the combustion furnace 16. Also, W
A pulverized coal amount detector 26 is arranged in the first pulverized coal transport system, and detectors 27 and 28 for detecting the pressure inside the wind box 22 are arranged in the wind box 22. The pressure detectors 27 and 28 are used to detect the amount of air from changes in pressure by understanding the relationship between the amount of air supplied to the wind box 22 and the pressure.
ボイラ負荷が１００％の場合には１石炭粉砕機での石炭
粉砕量を多くし、ボイラ負荷に相当する分の微粉炭が空
気によって各バーナに供給される。When the boiler load is 100%, the amount of coal pulverized by one coal pulverizer is increased, and pulverized coal corresponding to the boiler load is supplied to each burner by air.
燃焼用空気は、微粉炭供給量に応じて、これを完全に燃
焼するために必要な理論空気量に対し５通常約１．２倍
の過剰の空気が供給され、微粉炭の燃焼を完結するよう
に操作される。ボイラの運転は昼夜間、あるいは時間帯
によって電力の消費が異なるため、ボイラ負荷を変化さ
せることが重要であるが、第８図の実施例においては、
ボイラの負荷低減指令により、初めに石炭粉砕機での石
炭粉砕量を減少させ、各バーナへの微粉炭供給量を少な
くする。また、微粉炭の供給量に応じて、燃焼用空気量
も、ダンパ３１，３２の開度調整により各バーナに対す
る供給量を減少させ、１００％負荷と同様の燃焼条件に
なるよう、空気過剰率を制御する。Depending on the amount of pulverized coal supplied, the combustion air is usually 1.2 times more than the theoretical amount of air required to completely combust the pulverized coal, thereby completing the combustion of the pulverized coal. It is operated as follows. When operating a boiler, power consumption varies depending on day and night or time of day, so it is important to vary the boiler load, but in the example shown in Fig. 8,
The boiler load reduction command first reduces the amount of coal crushed in the coal crusher, reducing the amount of pulverized coal supplied to each burner. In addition, depending on the supply amount of pulverized coal, the amount of combustion air supplied to each burner is reduced by adjusting the opening of the dampers 31 and 32, and the excess air ratio is adjusted so that the combustion conditions are the same as those at 100% load. control.
そして、本実施例では、この微粉炭量検出器２６の圧力
をもとに、ウィンドボックス２２内の圧力検出器２７の
圧力を監視しながら、燃焼用空気量をダンパ３１，３２
により１１１！シ、燃焼用空気量に応じて噴出速度が低
下しないよう、可動ブロック１３を調節部材１４により
燃焼用空気流路内に挿入し、流路断面積を縮小して所定
の噴出速度になるように操作する。In this embodiment, based on the pressure of the pulverized coal amount detector 26, while monitoring the pressure of the pressure detector 27 in the wind box 22, the amount of combustion air is controlled by the dampers 31, 32.
By 111! In order to prevent the jetting speed from decreasing according to the amount of combustion air, the movable block 13 is inserted into the combustion air flow path by the adjustment member 14, and the cross-sectional area of the flow path is reduced to achieve a predetermined jetting speed. Manipulate.
第９図は本発明に係る微粉炭燃焼法を自動化する場合に
用いて好適な制御系の一実施例を示すブロック図である
。FIG. 9 is a block diagram showing an embodiment of a control system suitable for use when automating the pulverized coal combustion method according to the present invention.
すなわち、本実施例は、ボイラ負荷変動時に微粉炭およ
び燃焼用空気量に応じて燃焼用空気流路内の可動ブロッ
ク１３を自動的に操作する方法について説明する。That is, this embodiment describes a method of automatically operating the movable block 13 in the combustion air flow path according to the amount of pulverized coal and combustion air when the boiler load fluctuates.
第９図において、微粉炭搬送系統における微粉炭量の検
出値および、ウィンドボックス２２に供給される空気量
の検出値は、それぞれ検出器２６゜２７より演算器３３
に入力されて、常に微粉炭量と空気供給量とが監視され
、演算器３４がらの出力は制御装置３４に入力されて、
可動ブロック１３の移動方向移動距離を指定する。制御
装置３４からの出力はモータ駆虻ノ装置３５に人力され
る。そして、モータ線動装置３５からの指令によリモー
タ３６が回転し、接続部材３７．可動ブロック調節部材
１４を介して可動ブロック１３を移動させることができ
る。すなわち、前記モータ原動装置３５は、モータ３６
の回転方向と回転数とを制御し、またこの指令は制御装
置３４から出力される。In FIG. 9, the detected value of the amount of pulverized coal in the pulverized coal conveyance system and the detected value of the amount of air supplied to the wind box 22 are determined by the calculator 33 from the detectors 26 and 27, respectively.
The amount of pulverized coal and the amount of air supplied are constantly monitored, and the output from the calculator 34 is input to the control device 34.
Specify the moving distance of the movable block 13 in the moving direction. The output from the control device 34 is manually input to a motor drive device 35. Then, the remoter 36 rotates according to a command from the motor linear motion device 35, and the connecting member 37. The movable block 13 can be moved via the movable block adjustment member 14. That is, the motor driving device 35 is a motor 36
This command is output from the control device 34.
本発明は以上のごときであり、本発明によれば、ボイラ
の負荷変動に対し微粉炭量および燃焼用空気流量が変化
しても、微粉炭の安定な着火、保炎ができ、ひいては安
定した燃焼状態を維持できることに加えて、低空気比火
炎内で低酸素濃度を大きく形成できるため、燃焼初期に
発生したＮＯｘを効率よく還元し、ＮＯｘ排出量を大幅
に低減することができる。また１石炭の燃焼率も大幅に
向上することができ、これらの効果により、ボイラプラ
ント全体の性能および信頼性の向上をはかることができ
る。The present invention is as described above.According to the present invention, even if the amount of pulverized coal and the flow rate of combustion air change due to fluctuations in the load of the boiler, stable ignition and flame holding of pulverized coal can be achieved. In addition to being able to maintain the combustion state, it is possible to form a large low oxygen concentration within the low air ratio flame, making it possible to efficiently reduce NOx generated in the initial stage of combustion and significantly reduce the amount of NOx emissions. Furthermore, the combustion rate of one coal can be significantly improved, and these effects can improve the performance and reliability of the entire boiler plant.
第１図は本発明に係る微粉炭バーナの一実施例を示す縦
断面図、第２図は第１図の微粉炭バーナによる火炎形成
の状況を示す説明図、第３図〜第７図はいずれも実験結
果にもとづく本発明の効果説明図、第８図は第１図に示
す微粉炭バーナを微粉炭ボイラに適用した場合の一実施
例を示す炉内構成説明図、第９図は本発明に係る微粉炭
燃焼法を自動化する場合に用いて好適な制御系の一実施
例を示すブロック図、第１０図は従来提案に係る微粉炭
炉内脱硝燃焼装置の具体的−例を示す作用説明図、第１
１図は第１０図と比較して示す本発明バーナすなわち、
第１図に示す微粉炭バーナの作用説明図、第１２図はこ
れまた従来提案に係る微粉炭バーナの具体的−例を示す
作用説明図である。
３・・・流路断面積縮小部材、８・・・隔壁、１０・・
・三次空気流路、１３・・−可動ブロック、１４・・・
可動ブロン９１１１節部材、２３，２４．２５・・・分
配器、２６・・・微粉炭供給量検出器、２７．２８・・
・ウィンドボツク入内圧力検出器、３３・・演算器、３
４・・制御装置、３５・・・モータ駆動装置、３６・・
・モータ、３７・・・接続部材。FIG. 1 is a longitudinal sectional view showing an embodiment of the pulverized coal burner according to the present invention, FIG. 2 is an explanatory diagram showing the state of flame formation by the pulverized coal burner of FIG. 1, and FIGS. 3 to 7 are Both are diagrams explaining the effects of the present invention based on experimental results. Figure 8 is a diagram explaining the furnace internal configuration showing an example of applying the pulverized coal burner shown in Figure 1 to a pulverized coal boiler. Figure 9 is an illustration of the present invention. A block diagram showing an embodiment of a control system suitable for use when automating the pulverized coal combustion method according to the invention, and FIG. 10 is a block diagram showing a concrete example of a conventionally proposed pulverized coal furnace denitrification combustion device. Explanatory diagram, 1st
FIG. 1 shows the burner of the present invention in comparison with FIG.
FIG. 1 is an explanatory view of the operation of the pulverized coal burner, and FIG. 12 is an explanatory view of the operation of a pulverized coal burner according to a conventional proposal. 3... Channel cross-sectional area reducing member, 8... Partition wall, 10...
・Tertiary air flow path, 13...-Movable block, 14...
Movable bronze 9111 node member, 23, 24. 25...Distributor, 26...Pulverized coal supply amount detector, 27.28...
・Wind box inlet pressure detector, 33...Arithmetic unit, 3
4...Control device, 35...Motor drive device, 36...
- Motor, 37... connection member.
Claims (1)
バーナに供給する微粉炭および燃焼用空気量を変化する
ことによりボイラの負荷を変化させる微粉炭燃焼法にお
いて、各微粉炭バーナに供給される微粉炭および燃焼用
空気量をもとに、高負荷時には燃焼用空気流路の断面積
を大きくし、低負荷時には前記燃焼用空気流路の流路断
面積を縮小するよう、各微粉炭バーナの燃焼用空気流路
断面積を変化させ、燃焼用空気の噴出速度を所定速度に
調整することを特徴とする微粉炭燃焼法。 ２、火炉壁に複数個の微粉炭バーナを配置し、前記微粉
炭バーナに供給する微粉炭の量を検出する手段と、燃焼
用空気の供給量を検出する手段と、ボイラ負荷を変化さ
せるとき、微粉炭供給量に応じて燃焼用空気供給量を調
節する燃焼用空気量調整手段と、前記燃焼用空気供給量
をもとに、各微粉炭バーナの燃焼用空気流路断面積を変
化させ所定の噴出速度に調整して微粉炭を燃焼させる手
段とを具備してなることを特徴とする微粉炭ボイラ。 ３、微粉炭および微粉炭搬送用空気の混合気流路と、燃
焼用空気を二次空気および三次空気に分割供給する流路
とを有する微粉炭バーナにおいて、微粉炭および燃焼用
空気量をもとに三次空気流路断面積を変化させ、三次空
気の噴出速度を所定速度に調整する可動ブロックを三次
空気流路内に配置したことを特徴とする微粉炭バーナ。 ４、微粉炭および微粉炭搬送用空気の混合気流路と、燃
焼用空気流路を二次空気および三次空気に分割供給する
流路とを有する微粉炭バーナにおいて、前記混合気流路
と二次空気流路とを縮小する流路断面積縮小部材を設け
、この流路断面積縮小部材の後流側に、２０μｍ以下の
石炭粒子を流入させて微小粒子濃度を高める高温再循環
流形成領域を有することを特徴とする請求項３記載の微
粉炭バーナ。 ５、微粉炭および微粉炭搬送用空気の混合気流路と、燃
焼用空気流路を二次空気および三次空気に分割供給する
流路とを有する微粉炭バーナにおいて、前記混合気流路
と二次空気流路とを縮小する流路断面積縮小部材を設け
、この流路断面積縮小部材の後流側に、空気比（＝空気
量／可燃性分を燃焼させるための理論空気量）が０．４
〜０．６の領域を形成したことを特徴とする請求項３記
載の微粉炭バーナ。[Claims] 1. A pulverized coal combustion method in which a plurality of pulverized coal burners are arranged on the furnace wall and the load on the boiler is changed by changing the amount of pulverized coal and combustion air supplied to the pulverized coal burners. Based on the amount of pulverized coal and combustion air supplied to each pulverized coal burner, the cross-sectional area of the combustion air flow path is increased at high loads, and the cross-sectional area of the combustion air flow paths is increased at low loads. A pulverized coal combustion method characterized by changing the cross-sectional area of the combustion air flow path of each pulverized coal burner and adjusting the ejection speed of combustion air to a predetermined speed so as to reduce the combustion air flow rate. 2. When a plurality of pulverized coal burners are arranged on the furnace wall, a means for detecting the amount of pulverized coal supplied to the pulverized coal burners, a means for detecting the amount of supply of combustion air, and a method for changing the boiler load. a combustion air amount adjusting means for adjusting the amount of combustion air supplied in accordance with the amount of pulverized coal supplied; 1. A pulverized coal boiler comprising means for adjusting the ejection speed to a predetermined ejection speed and combusting the pulverized coal. 3. In a pulverized coal burner having a mixture flow path for pulverized coal and air for transporting pulverized coal, and a flow path for dividing and supplying combustion air into secondary air and tertiary air, A pulverized coal burner characterized in that a movable block is disposed in the tertiary air flow path to change the cross-sectional area of the tertiary air flow path and adjust the ejection speed of the tertiary air to a predetermined speed. 4. In a pulverized coal burner having a mixture flow path for pulverized coal and pulverized coal conveying air, and a flow path for dividing and supplying the combustion air flow path into secondary air and tertiary air, the mixture flow path and the secondary air A flow path cross-sectional area reducing member is provided to reduce the flow path, and a high-temperature recirculation flow forming region is provided on the downstream side of the flow path cross-sectional area reducing member to allow coal particles of 20 μm or less to flow in to increase the concentration of fine particles. The pulverized coal burner according to claim 3, characterized in that: 5. In a pulverized coal burner having a mixture flow path for pulverized coal and pulverized coal conveying air, and a flow path for dividing and supplying the combustion air flow path into secondary air and tertiary air, the mixture flow path and the secondary air A flow path cross-sectional area reducing member is provided to reduce the flow path, and an air ratio (=air amount/theoretical air amount for burning flammable components) is 0. 4
The pulverized coal burner according to claim 3, characterized in that the pulverized coal burner has a region of 0.6 to 0.6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2112509A JP2522583B2 (en) | 1990-04-27 | 1990-04-27 | Pulverized coal combustion method and pulverized coal boiler |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2112509A JP2522583B2 (en) | 1990-04-27 | 1990-04-27 | Pulverized coal combustion method and pulverized coal boiler |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH049511A true JPH049511A (en) | 1992-01-14 |
| JP2522583B2 JP2522583B2 (en) | 1996-08-07 |
Family
ID=14588431
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2112509A Expired - Fee Related JP2522583B2 (en) | 1990-04-27 | 1990-04-27 | Pulverized coal combustion method and pulverized coal boiler |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2522583B2 (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6461145B1 (en) * | 1999-02-25 | 2002-10-08 | Stein Heurtey | Flat flame burners |
| JP2002369607A (en) * | 2001-06-14 | 2002-12-24 | Iseki & Co Ltd | Lift frame for seedling planter |
| US7175423B1 (en) * | 2000-10-26 | 2007-02-13 | Bloom Engineering Company, Inc. | Air staged low-NOx burner |
| JP2008196741A (en) * | 2007-02-09 | 2008-08-28 | Ihi Corp | Pulverized coal burner |
| JP2012149815A (en) * | 2011-01-19 | 2012-08-09 | Miura Co Ltd | Burner |
| CN103017161A (en) * | 2012-12-19 | 2013-04-03 | 上海锅炉厂有限公司 | Swirl pulverized coal burner |
| CN110887037A (en) * | 2019-12-19 | 2020-03-17 | 沈阳环境科学研究院 | Low-nitrogen combustion device for enhancing pulverized coal gasification |
| CN113418206A (en) * | 2021-06-10 | 2021-09-21 | 国网湖南省电力有限公司 | Primary air adjusting method and device based on pulverized coal burner nozzle temperature measurement |
| WO2022180735A1 (en) * | 2021-02-25 | 2022-09-01 | 太平洋セメント株式会社 | Cement kiln burner and method for operating same |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59205507A (en) * | 1983-05-09 | 1984-11-21 | Babcock Hitachi Kk | In-furnace denitrifying combustion device of pulverized coal |
| JPS6012002U (en) * | 1983-07-04 | 1985-01-26 | バブコツク日立株式会社 | Pulverized coal combustion equipment |
-
1990
- 1990-04-27 JP JP2112509A patent/JP2522583B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59205507A (en) * | 1983-05-09 | 1984-11-21 | Babcock Hitachi Kk | In-furnace denitrifying combustion device of pulverized coal |
| JPS6012002U (en) * | 1983-07-04 | 1985-01-26 | バブコツク日立株式会社 | Pulverized coal combustion equipment |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6461145B1 (en) * | 1999-02-25 | 2002-10-08 | Stein Heurtey | Flat flame burners |
| US7175423B1 (en) * | 2000-10-26 | 2007-02-13 | Bloom Engineering Company, Inc. | Air staged low-NOx burner |
| JP2002369607A (en) * | 2001-06-14 | 2002-12-24 | Iseki & Co Ltd | Lift frame for seedling planter |
| JP2008196741A (en) * | 2007-02-09 | 2008-08-28 | Ihi Corp | Pulverized coal burner |
| JP2012149815A (en) * | 2011-01-19 | 2012-08-09 | Miura Co Ltd | Burner |
| CN103017161A (en) * | 2012-12-19 | 2013-04-03 | 上海锅炉厂有限公司 | Swirl pulverized coal burner |
| CN110887037A (en) * | 2019-12-19 | 2020-03-17 | 沈阳环境科学研究院 | Low-nitrogen combustion device for enhancing pulverized coal gasification |
| CN110887037B (en) * | 2019-12-19 | 2024-05-24 | 沈阳环境科学研究院 | Low-nitrogen combustion device for enhancing pulverized coal gasification |
| WO2022180735A1 (en) * | 2021-02-25 | 2022-09-01 | 太平洋セメント株式会社 | Cement kiln burner and method for operating same |
| CN113418206A (en) * | 2021-06-10 | 2021-09-21 | 国网湖南省电力有限公司 | Primary air adjusting method and device based on pulverized coal burner nozzle temperature measurement |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2522583B2 (en) | 1996-08-07 |
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