JP2002121609A - Method for operating blast furnace by injecting large quantity of pulverized coal - Google Patents

Method for operating blast furnace by injecting large quantity of pulverized coal

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Publication number
JP2002121609A
JP2002121609A JP2001117728A JP2001117728A JP2002121609A JP 2002121609 A JP2002121609 A JP 2002121609A JP 2001117728 A JP2001117728 A JP 2001117728A JP 2001117728 A JP2001117728 A JP 2001117728A JP 2002121609 A JP2002121609 A JP 2002121609A
Authority
JP
Japan
Prior art keywords
pulverized coal
oxygen
blast furnace
blown
furnace
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
Application number
JP2001117728A
Other languages
Japanese (ja)
Other versions
JP4742442B2 (en
Inventor
Michitaka Sato
道貴 佐藤
Tatsuro Ariyama
達郎 有山
Masahiro Matsuura
正博 松浦
Ryota Murai
亮太 村井
Kazuya Goto
和也 後藤
Akinori Murao
明紀 村尾
Atsushi Sakai
敦 酒井
Shinji Matsubara
真二 松原
Koujiyu Mori
候寿 森
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.)
JFE Engineering Corp
Original Assignee
NKK Corp
Nippon Kokan 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 NKK Corp, Nippon Kokan Ltd filed Critical NKK Corp
Priority to JP2001117728A priority Critical patent/JP4742442B2/en
Publication of JP2002121609A publication Critical patent/JP2002121609A/en
Application granted granted Critical
Publication of JP4742442B2 publication Critical patent/JP4742442B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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  • Blast Furnaces (AREA)
  • Manufacture Of Iron (AREA)

Abstract

PROBLEM TO BE SOLVED: To stably operate a blast furnace by injecting large quantity of pulverized coals while suppressing the occurrence and growth of a bird's nest at the deep position of the raceway by a simple method and sufficiently keeping permeability at the lower part in the furnace. SOLUTION: The injecting speed of the pulverized coal 5 from a lance 4 inserted into a blow pipe 3 is changed within 50-150% of the average injecting speed and changed at >=15 times per one min, desirably, at the frequency of 15-30 times. The lance 4 having a concentric double-tube structure is used, the pulverized coal is injected from the inner tube, and oxygen-enriched gas or pure oxygen is blown from the gap between the inner tube and the outer tube. The injecting speed of the pulverized coal is periodically changed and the oxygen-enriched gas or the like is brown synchronously therewith. Further, a nozzle is inserted into a blow pipe 3 and the oxygen is blown at >=1.5 times of the blasting rate at the top end part of the tuyere. The oxygen-enriched gas or the like is brown only at the necessary time in accordance with the stable state of the furnace condition, and it is preferable to blow the oxygen- enriched gas intermittently.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】この発明は、多量の微粉炭を
高炉に吹き込みつつ、安定した操業を行なうことを可能
とする、微粉炭の多量吹込みによる高炉操業技術に関す
るものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blast furnace operating technique using a large amount of pulverized coal, which enables a stable operation while blowing a large amount of pulverized coal into a blast furnace.

【０００２】[0002]

【従来の技術】高炉への微粉炭吹き込み操業技術は、微
粉炭と高炉用コークスとの価格差によるコスト効果が大
きいことにより多数の高炉において採用され、溶銑製造
における合理化に大きく寄与している。また、高炉への
微粉炭吹き込み量を増やすことによりコークス炉の負荷
軽減を図ることができ、コークス炉の延命にも寄与する
ことが可能であることにより、一層多量の微粉炭を吹き
込もうとする高炉操業が指向されるようになった。2. Description of the Related Art The technique of pulverized coal injection into blast furnaces has been adopted in many blast furnaces due to the large cost effect due to the price difference between pulverized coal and coke for blast furnaces, and has greatly contributed to the rationalization of hot metal production. In addition, by increasing the amount of pulverized coal injected into the blast furnace, it is possible to reduce the load on the coke oven and contribute to prolonging the life of the coke oven. Blast furnace operations have become more oriented.

【０００３】ところが、高炉への微粉炭吹き込み量を増
やしていくと、特に微粉炭吹込み量を１８０ｋｇ／ｔ−
溶銑以上までに増やしていくと、炉下部の通気不良、炉
体熱負荷の上昇、及び炉内ガスの周辺流化に伴なう荷下
がり変動の増大等、高炉の安定操業を維持する上で種々
の重大な障害が顕在化してくる。However, when the pulverized coal injection amount into the blast furnace is increased, the pulverized coal injection amount is particularly increased to 180 kg / t-.
Increasing the amount of hot metal to more than that required to maintain stable operation of the blast furnace, such as poor ventilation in the lower part of the furnace, an increase in the furnace body heat load, and an increase in load drop due to peripheral flow of gas in the furnace. Various serious obstacles become apparent.

【０００４】こうした高炉操業の安定性阻害要因の一つ
として、レースウェイ奥のコークス充填層粒子の間隙
に、スラグが多量にホールドアップされた層であって通
気性を阻害する、通称鳥の巣といわれる層の生成・成長
を挙げることができる。図１１及び図１２に、高炉の炉
内に微粉炭を吹込む状況、及び鳥の巣の形成状況を説明
する縦断面模式図を示す。高炉１の羽口２部に連接され
たブローパイプ３の周壁を貫通して挿入された微粉炭吹
込み用ランス４から微粉炭５を高速の熱風６中に噴射す
る。微粉炭５は、ブローパイプ３内、羽口２内、及びブ
ローパイプ３の前方に形成されるレースウェイ７内で燃
焼する。微粉炭中の灰分はこの燃焼時に遊離し一部溶融
する。多量の微粉炭吹込みを行なった場合には、レース
ウェイ７周囲奥のコークス８充填層に対して、上方から
滴下するメタル９及びスラグ１０が供給されると共に、
微粉炭５及びコークス８の燃焼により発生した多量の灰
分が供給される。特に、このレースウェイ７奥端の内面
は、コークス８及び微粉炭５からきた灰分の酸性成分ス
ラグＳｉＯ2−Ａｌ2Ｏ3を主体物質として形成されてい
るので、粘性及び融点が高く、コークス８充填層の空隙
を埋め易く、こうしてレースウェイ７奥端部に鳥の巣１
１が形成される。このため、レースウェイ７に入ってき
たガスの炉芯方向への通気性が阻害されて、そのガスの
炉周辺流が促進される。鳥の巣１１の存在は、更に炉壁
１２部への熱負荷を上昇させると共に、レースウェイ７
から排出されるガスの流速を上昇させるので、レースウ
ェイ７へ落下してくるコークスやメタル９及びスラグ１
０はフラッディングを起こし易い状態となるばかりか、
炉内の荷下がり変動や吹抜け等の炉況悪化の原因となる
場合もある。また、鳥の巣の生成は、レースウェイ深度
の縮小や縦長化を誘起し、これらの現象もまた、炉内ガ
ス流れの周辺流化や炉壁熱負荷の上昇を助長する要因と
なる。One of the factors that hinder the stability of the blast furnace operation is a bird's nest, which is a layer in which a large amount of slag is held up in the gaps between the coke packed bed particles at the back of the raceway and impairs air permeability. The generation and growth of a layer referred to as the above can be mentioned. FIG. 11 and FIG. 12 are schematic vertical cross-sectional views for explaining the situation where pulverized coal is blown into the blast furnace and the situation where bird nests are formed. Pulverized coal 5 is injected into high-speed hot air 6 from a pulverized coal injection lance 4 inserted through a peripheral wall of a blow pipe 3 connected to the tuyere 2 of the blast furnace 1. The pulverized coal 5 burns in the blow pipe 3, the tuyere 2, and the raceway 7 formed in front of the blow pipe 3. The ash in the pulverized coal is released and partially melted during this combustion. When a large amount of pulverized coal is blown, the metal 9 and the slag 10 dripped from above are supplied to the coke 8 packed bed around the raceway 7 and
A large amount of ash generated by the combustion of the pulverized coal 5 and coke 8 is supplied. In particular, since the inner surface of the rear end of the raceway 7 is formed mainly of slag SiO 2 —Al 2 O 3, which is an acidic component of ash from the coke 8 and the pulverized coal 5, the viscosity and the melting point are high, and the coke 8 It is easy to fill the voids in the packed bed and thus the bird's nest 1
1 is formed. For this reason, the gas permeability of the gas entering the raceway 7 in the furnace core direction is impaired, and the flow of the gas around the furnace is promoted. The presence of the bird's nest 11 further increases the heat load on the furnace wall 12 and increases the raceway 7
Increases the flow velocity of gas discharged from the coke, metal 9 and slag 1
0 not only makes flooding easy,
In some cases, this may cause deterioration of the furnace condition such as fluctuations in the load inside the furnace and blow-through. Also, the formation of bird's nests induces a decrease in raceway depth and an increase in length, and these phenomena also contribute to peripheral flow of gas in the furnace and increase in heat load on the furnace wall.

【０００５】一般に、微粉炭を多量に吹込む高炉におい
て、安定した高炉操業を行なうためには、特に炉下部の
通気性を維持して、炉壁熱負荷や荷下がり変動が起こら
ないような状況を作り出すことが不可欠であり、このた
めにはレースウェイ部における鳥の巣の生成を抑制する
と同時に、レースウェイ深度を確保することが必要であ
る。Generally, in a blast furnace in which a large amount of pulverized coal is blown, in order to operate the blast furnace stably, it is necessary to maintain air permeability especially in the lower part of the furnace so that the heat load on the furnace wall and fluctuations in the unloading do not occur. It is indispensable to create a bird's nest in the raceway section, and at the same time, to secure the raceway depth.

【０００６】この鳥の巣の生成を抑制する方法として、
特公平６−８９３８２号公報には、コークス及び微粉炭
からの酸性成分スラグＳｉＯ2−Ａｌ2Ｏ3の粘性及び融
点を下げることを目的として、ＣａＯ及びＭｇＯ等の塩
基性微粉媒溶剤を微粉炭と同時に吹き込み、微粉炭から
くる灰分の滓化を促進させることにより、これを溶解・
除去する方法が開示されている（以下、先行技術１とい
う）。この方法によれば、微粉炭及びコークスの灰分と
塩基性微粉媒溶剤とは即座に反応して、低融点のスラグ
を形成し、滴下するので、速効性の高い方法である。As a method of suppressing the formation of the bird's nest,
Japanese Patent Publication No. 6-89382 discloses a method for reducing the viscosity and melting point of acidic component slag SiO 2 —Al 2 O 3 from coke and pulverized coal by using a basic pulverized solvent such as CaO and MgO. At the same time, it is blown to promote ash slag coming from pulverized coal,
A removal method is disclosed (hereinafter referred to as Prior Art 1). According to this method, the ash of the pulverized coal and coke and the basic pulverizing medium solvent react immediately to form a slag having a low melting point and are dropped, so that the method is highly effective.

【０００７】しかしながら、先行技術１によって溶解除
去効果を発揮させるためには、塩基性微粉媒溶剤と微粉
炭中の灰分とを混合したときの塩基度を調整することが
必要であり、１０ｍａｓｓ％程度の灰分を含有する通常
の微粉炭を使用するときには、微粉炭重量に対する約１
０ｍａｓｓ％という高率の塩基性微粉媒溶剤を吹き込ま
なくてはならない。このため、微粉炭の吹き込み量が多
くなるにつれて、塩基性微粉媒溶剤の吹込み量も多くな
る。従って、微粉炭を多量に吹き込もうとする場合に
は、塩基性微粉媒溶剤の粉砕設備の増強を余儀なくされ
たり、また設備的増強が不要な場合であっても、塩基性
微粉媒溶剤は微粉炭に比較して硬いので、粉砕条件の再
設定等の調整が必要となる。更に、焼結鉱製造工程にお
いても、微粉炭の吹込み量、あるいは炭種、特に灰分量
の変更に応じたきめ細かな塩基度調整及び配合条件並び
に焼成条件等の大幅な見直しが必要となる。また、微粉
炭の燃焼促進に対して、同時に吹き込まれた塩基性微粉
媒溶剤は何ら寄与しないばかりか、塩基性微粉媒溶剤自
身の昇温・溶融のための吸熱を伴なうので、微粉炭の燃
焼性が阻害される可能性もある。However, in order to exhibit the dissolving and removing effect according to the prior art 1, it is necessary to adjust the basicity when mixing the basic fine powder medium solvent and the ash in the pulverized coal, and it is necessary to adjust the basicity to about 10 mass%. When ordinary pulverized coal containing ash is used, about 1
A high percentage of basic fine particle solvent of 0 mass% must be blown. For this reason, as the blowing amount of the pulverized coal increases, the blowing amount of the basic pulverizing medium solvent also increases. Therefore, if a large amount of pulverized coal is to be blown in, the basic fine powder medium solvent must be crushed and the basic fine powder medium solvent must be enhanced. Since it is harder than pulverized coal, adjustment such as resetting of pulverization conditions is required. Further, also in the sinter ore production process, it is necessary to finely adjust the basicity according to the amount of pulverized coal to be injected or the type of coal, especially the amount of ash, and to reconsider the blending conditions and firing conditions. In addition, the basic pulverulent solvent blown at the same time does not contribute to the promotion of pulverized coal combustion, and also involves the endothermic heat of the basic pulverized solvent itself to melt and melt. May be impaired.

【０００８】[0008]

【発明が解決しようとする課題】上述したように、先行
技術１によれば、高炉への微粉炭吹込み量が少ない場合
には鳥の巣の形成・成長の抑制に対して速効性が発揮さ
れ得る。しかしながら、その際には塩基性微粉媒溶剤と
微粉炭中の灰分との混合物の適切な塩基度調整操作が新
たに必要となる他、特に微粉炭吹込み量を増やした場合
には、当該塩基度調整上、塩基性微粉媒溶剤の大量添加
問題、粉砕設備及び粉砕条件適正化問題、また焼結鉱製
造条件の整合化、更には大量塩基性微粉媒溶剤の熱的補
償問題が発生する。このように、先行技術１では製銑工
程全般に及ぼす影響が極めて大きい。As described above, according to the prior art 1, when the amount of pulverized coal injected into the blast furnace is small, a rapid effect is exhibited in suppressing the formation and growth of bird nests. Can be done. However, in that case, an appropriate basicity adjustment operation of the mixture of the basic pulverized medium solvent and the ash in the pulverized coal is newly required, and especially when the pulverized coal injection amount is increased, the base is not affected. In adjusting the degree, the problem of adding a large amount of basic fine powder medium, the problem of optimizing the crushing equipment and crushing conditions, the matching of the sinter production conditions, and the problem of thermal compensation of the large amount of basic fine powder solvent occur. As described above, in the prior art 1, the influence on the entire iron making process is extremely large.

【０００９】従って、この発明の目的は、多量に微粉炭
を吹き込む場合においても、上述した各種問題を解決
し、しかもより簡便な方法により鳥の巣の生成を抑制
し、炉内下部の通気性が良好であって、安定した高炉操
業が可能となるような、微粉炭の多量吹込みによる高炉
操業方法を提供することにある。Therefore, an object of the present invention is to solve the above-mentioned various problems even when a large amount of pulverized coal is blown, suppress the formation of bird's nests by a simpler method, and improve the air permeability in the lower part of the furnace. It is an object of the present invention to provide a method for operating a blast furnace by injecting a large amount of pulverized coal so that the blast furnace can be operated stably.

【００１０】[0010]

【課題を解決するための手段】本発明者等は、上述した
観点から鋭意研究を重ねた結果、下記知見を得た。即
ち、鳥の巣の生成・成長機構を詳細に検討し、その生成
・成長の必須要件と当該必須要件の破壊手段を検討する
ことに着手した。具体的には下記の通りである。Means for Solving the Problems The inventors of the present invention have conducted intensive studies from the above-mentioned viewpoints, and have obtained the following findings. In other words, we started to examine the mechanism of bird nest generation and growth in detail, and to examine the essential requirements for its production and growth and the means of destruction of the essential requirements. Specifically, it is as follows.

【００１１】［課題解決のための着想及び解決方法−そ
の１］鳥の巣は、その生成・成長により形成される。そ
の際、その生成・成長は、レースウェイ奥内面付近で起
こる。そこで、本発明者等は、鳥の巣が生成し、成長す
る位置を強制的に移動させる状態を作り出すことによ
り、鳥の巣が定常的に生成・成長し得る条件の安定性を
強制的に崩して、鳥の巣の形成を抑制することを着想し
た。しかもその際、鳥の巣の生成・成長の抑制効果を著
しく高めるためには、当該生成・成長の位置を強制的に
移動させる周期を、特定の範囲内に限定しなければ顕著
な効果は発揮されないことを見出した。[Inspiration and Solution for Solving the Problem-Part 1] A bird's nest is formed by its generation and growth. At that time, the generation / growth occurs near the inner surface of the raceway. Therefore, the present inventors have forcibly created a state in which a bird's nest is generated and grow, and forcibly move the position where the bird's nest is generated, thereby forcing the stability of conditions under which the bird's nest can be constantly generated and grown. The idea was to break it down and suppress the formation of bird nests. In addition, at this time, in order to significantly enhance the effect of suppressing the generation and growth of the bird's nest, a remarkable effect is exhibited unless the period for forcibly moving the position of the generation and growth is limited to a specific range. Not found.

【００１２】先ず、鳥の巣の形成機構は前述したよう
に、レースウェイ内で燃焼した微粉炭及びコークス中の
灰分が、レースウェイ奥のコークス層へ供給され、上方
から滴下してくる鉱石由来のスラグと共に、これらスラ
グがそのコークス層中に多量にホールドアップされた新
たな層を形成するものと推定される。そして、鳥の巣の
生成位置は、羽口先のガス流速、レースウェイ内コーク
ス粒径、レースウェイ内空隙率及び温度分布等の相互作
用によって総合的に決まると考えられる。送風条件がほ
ぼ一定なら、微粉炭吹込み比が高い場合は低い場合に比
べて、羽口ガス流速は大きくなりやすく、このため、レ
ースウェイ深度を大きくする効果を有するが、反対に羽
口先での急激な微粉炭燃焼によって急速に酸素を消費す
るため、レースウェイ内における最高温度位置は羽口先
端に近づき、同時にレースウェイ奥に向かって急激に温
度低下を起こすため、レースウェイ深度は低下する効果
も有する。現実の高炉では、後者の効果の方が大きいの
で、微粉炭吹込み比が高いほどレースウェイ深度は低下
すると考えられる。First, as described above, the mechanism of bird nest formation is that pulverized coal burned in the raceway and ash in the coke are supplied to the coke layer at the back of the raceway, and the ore originates from the ore dropping from above. It is presumed that, together with the slags, these slags form a new layer that is heavily held up in the coke layer. It is considered that the position where the bird's nest is formed is determined comprehensively by interactions such as the gas flow velocity at the tuyere tip, the particle size of coke in the raceway, the porosity in the raceway, and the temperature distribution. If the blowing conditions are almost constant, the tuyere gas flow rate tends to increase when the pulverized coal injection ratio is high compared to when the pulverized coal injection ratio is low, and thus has the effect of increasing the raceway depth. Rapidly consumes oxygen due to rapid pulverized coal combustion, the maximum temperature position in the raceway approaches the tuyere tip, and at the same time, the temperature suddenly decreases toward the back of the raceway, so the raceway depth decreases It also has an effect. In an actual blast furnace, the latter effect is greater, so it is considered that the higher the pulverized coal injection ratio, the lower the raceway depth.

【００１３】鳥の巣の生成位置を上記の通り推定すれ
ば、微粉炭吹込み比が一定なら、レースウェイ奥行きの
位置はほぼ一定値となる。従って、鳥の巣が生成する位
置もほぼ一定の位置に固定されることになる。それ故、
上記通常の微粉炭吹込み方法においては、鳥の巣の形成
条件が安定している定常状態となるので、極めて層厚の
厚い鳥の巣が形成されているものと考えられる。When the position of the bird's nest is estimated as described above, if the pulverized coal injection ratio is constant, the position of the depth of the raceway is substantially constant. Therefore, the position where the bird's nest is generated is also fixed at a substantially constant position. Therefore,
In the ordinary pulverized coal injection method, since the bird nest formation conditions are in a steady state where the conditions are stable, it is considered that a bird nest having an extremely thick layer is formed.

【００１４】そこで、本発明者等は鳥の巣の生成を抑制
するための方法として、微粉炭吹込みの高炉操業におい
て制御をし易い操作因子として微粉炭吹込み比を選定
し、上述のようにレースウェイ内の温度分布を変化させ
ることによってレースウェイ深度を強制的に変化させる
ことにした。Therefore, as a method for suppressing the formation of bird's nests, the present inventors have selected the pulverized coal injection ratio as an operation factor that is easy to control in the blast furnace operation of pulverized coal injection, and as described above. The raceway depth was forcibly changed by changing the temperature distribution in the raceway.

【００１５】こうして、レースウェイ奥行きを一定値に
安定化させることなく、レースウェイ奥内面の位置を強
制的に経時変化させ、鳥の巣の形成位置に存在するコー
クス粒子層に対して前後方向への振動運動を起こさせた
り、あるいはせん断応力等を作用させることにより、鳥
の巣が安定して生成・成長し得るような定常状態へ到達
する前に、その生成・成長を阻止すると共に、鳥の巣を
構成するコークス粒子の間隙内にホールドアップされて
いるスラグを、機械的作用により積極的に振るい落とし
て、スラグのホールドアップ量を減らそうとするもので
ある。In this way, without stabilizing the depth of the raceway to a constant value, the position of the inner surface of the raceway is forcibly changed with time, so that the position of the coke particle layer existing at the position where the bird's nest is formed is moved forward and backward. Before the bird's nest reaches a steady state in which it can stably generate and grow, the generation and growth of the bird's nest can be prevented, and the bird's nest can be prevented. The slag held up in the gaps between the coke particles forming the nest is actively shaken down by a mechanical action to reduce the slag hold-up amount.

【００１６】本発明者等は更に、上記のようにしてレー
スウェイ深度を大・小に変化させるに当っては、その変
化の周期の長短を特定の範囲内に限定することによりは
じめて、鳥の巣の生成・成長に対して著しい抑制効果が
発揮されることをも見出した。In order to change the depth of the raceway to a large or small value as described above, the present inventors further limit the length of the cycle of the change to a specific range only when the length of the cycle is changed. It has also been found that a remarkable inhibitory effect is exerted on nest formation and growth.

【００１７】この発明の第１は、上記知見により得られ
たものであり、その要旨は下記の通りである。即ち、請
求項１記載の発明に係る微粉炭の多量吹込みによる高炉
操業方法は、高炉の羽口からその高炉の炉内に熱風を吹
き込むために、その羽口の手前に連接して設けられたブ
ローパイプの周壁を貫通して挿入された微粉炭吹込み用
ランスを用いて、上記高炉に１８０ｋｇ／ｔ−溶銑以上
の微粉炭を吹き込む高炉の操業方法において、上記微粉
炭吹込み用ランスからの当該微粉炭の吹込み速度を、そ
の微粉炭の平均吹込み速度の５０〜１５０％の範囲内に
おいて変化させ、且つその変化をさせる頻度を１分間に
１５回以上とすることに特徴を有するものである。The first aspect of the present invention has been obtained based on the above findings, and the gist is as follows. That is, the method for operating a blast furnace by injecting a large amount of pulverized coal according to the invention of claim 1 is provided in front of the tuyere in order to blow hot air from the tuyere of the blast furnace into the furnace of the blast furnace. Using a pulverized coal injection lance inserted through the peripheral wall of the blowpipe into the blast furnace, wherein pulverized coal of 180 kg / t-hot metal or more is blown into the blast furnace. Characterized in that the blowing speed of the pulverized coal is changed within a range of 50 to 150% of the average blowing speed of the pulverized coal, and the frequency of the change is set to 15 times or more per minute. Things.

【００１８】請求項２記載の発明に係る微粉炭の多量吹
込みによる高炉操業方法は、請求項１記載の発明におい
て、上記微粉炭の吹込み速度を変化させる頻度を、更に
望ましい条件として、１分間に１５〜３０回の範囲内と
することに特徴を有するものである。[0018] In the blast furnace operating method according to the second aspect of the present invention, a large amount of pulverized coal is blown. It is characterized in that it is within the range of 15 to 30 times per minute.

【００１９】請求項３記載の発明に係る微粉炭の多量吹
込みによる高炉操業方法は、請求項１記載の発明におい
て、上記微粉炭吹込み用ランスとして同心２重管構造の
ランスを用い、その内管から当該微粉炭を吹込み、そし
てその内管と外管との間隙から酸素富化ガス又は純酸素
を吹き込むことに特徴を有するものである。According to a third aspect of the present invention, there is provided the blast furnace operating method according to the first aspect of the present invention, wherein a lance having a concentric double pipe structure is used as the lance for injecting the pulverized coal. It is characterized in that the pulverized coal is blown from the inner pipe and the oxygen-enriched gas or pure oxygen is blown from the gap between the inner pipe and the outer pipe.

【００２０】請求項４記載の発明に係る微粉炭の多量吹
込みによる高炉操業方法は、請求項２載の発明におい
て、上記微粉炭吹込み用ランスとして同心２重管構造の
ランスを用い、その内管から当該微粉炭を吹込み、そし
てその内管と外管との間隙から酸素富化ガス又は純酸素
を吹き込むことに特徴を有するものである。According to a fourth aspect of the present invention, there is provided a method for operating a blast furnace by injecting a large amount of pulverized coal, wherein a lance having a concentric double pipe structure is used as the lance for injecting pulverized coal. It is characterized in that the pulverized coal is blown from the inner pipe and the oxygen-enriched gas or pure oxygen is blown from the gap between the inner pipe and the outer pipe.

【００２１】請求項５記載の発明に係る微粉炭の多量吹
込みによる高炉操業方法は、請求項３又は請求項４記載
の発明において、上記２重管構造ランスの内管から吹き
込む微粉炭吹込み速度の変化を、周期的変化パターンに
設定し、且つ、その微粉炭吹込み速度の周期的変化パタ
ーンに同調させて、上記内管と外管との間隙から吹き込
む上記酸素富化ガス又は純酸素の吹込み速度を、その酸
素富化ガス又は純酸素の平均吹込み速度の５０〜１５０
％の範囲内において変化させることに特徴を有するもの
である。According to a fifth aspect of the present invention, there is provided a method for operating a blast furnace by injecting a large amount of pulverized coal according to the third or fourth aspect of the present invention. The oxygen-enriched gas or pure oxygen blown from the gap between the inner pipe and the outer pipe by setting the change of the speed in a periodic change pattern and synchronizing with the periodic change pattern of the pulverized coal injection speed. Of the oxygen-enriched gas or pure oxygen at 50 to 150 times the average blowing rate of the oxygen-enriched gas or pure oxygen.
%.

【００２２】［課題解決のための着想及び解決方法−そ
の２］鳥の巣は、レースウェイ内で燃焼した微粉炭及び
コークス中の灰分が、レースウェイ奥内面付近のコーク
ス層へ供給され、一方、上方から滴下する鉱石由来のス
ラグと同化しつつ、これらスラグが当該コークス粒子の
間隙に多量にホールドアップされて、空隙率の低い層が
形成されたものであると推定される。この結果、レース
ウェイから吹き込まれたガス流の炉芯方向への流れが阻
害されるので、レースウェイ奥の温度が低下する。この
ため、鳥の巣の温度が低下し、従って、鳥の巣にホール
ドアップされたスラグの粘度が上昇するので、鳥の巣の
厚さがますます厚く成長することになる。そこで、本発
明者等は、鳥の巣の温度を積極的に上昇させることによ
り、鳥の巣の構成要素であるコークス粒子間にホールド
アップされたスラグの粘度を低下させて、当該スラグが
コークス粒子間にホールドアップされ難い環境条件を作
り出すことを着想した。そして、本発明者等は更に、鳥
の巣の他の構成要素であるコークス粒子（あるいはコー
クス粉）を、通常状態よりも一層積極的に燃焼させるこ
とにより、上記スラグがコークス粒子間にホールドアッ
プされ難い環境条件を作り出すことを着想した。[Idea for Solving the Problem and Solution—Part 2] In the bird's nest, the pulverized coal burned in the raceway and the ash in the coke are supplied to the coke layer near the inner surface of the raceway. It is estimated that a large amount of the slag was held up in the gaps between the coke particles while assimilating with the ore-derived slag dropped from above, and a layer having a low porosity was formed. As a result, the flow of the gas flow blown from the raceway toward the core becomes obstructed, so that the temperature at the back of the raceway decreases. This reduces the temperature of the bird's nest and therefore increases the viscosity of the slag held up in the bird's nest, which results in the bird's nest growing more and more thick. Therefore, the present inventors have actively increased the temperature of the bird's nest, thereby reducing the viscosity of the slag held up between the coke particles that are the components of the bird's nest, and The idea was to create an environmental condition that would be difficult to hold up between particles. Further, the present inventors further burn the coke particles (or coke powder), which is another component of the bird's nest, more aggressively than in the normal state, so that the slag is held up between the coke particles. The idea was to create an environmental condition that was difficult to do.

【００２３】本発明者等は、上記着想を鳥の巣形成の抑
制に対する効果的な高炉操業技術とするために、鋭意研
究を重ねた結果、下記知見を得た。即ち、レースウェイ
奥付近の鳥の巣形成領域の温度低下を防止すると共に、
当該領域の温度を積極的に高めること、及び、当該領域
のコークス粒子（あるいはコークス粉）を、通常の操業
状態よりも一層積極的に燃焼させること、の両方に対し
て同時に効果を発揮し得る方法として、下記方法により
その効果が著しく発揮され、しかも制御操作が容易であ
り優れていることがわかった。その方法の要点は、微粉
炭吹込み用ランスに加えて更に、酸素富化ガス又は純酸
素吹込み用ノズルを、微粉炭吹込み用ランスに準じ、ブ
ローパイプ周壁を貫通して挿入し、当該ノズルから酸素
富化ガス又は純酸素を、微粉炭吹込み時に、ブローパイ
プから高炉内へ吹き込む送風である熱風の羽口先端にお
ける流速の１．５倍以上の流速で噴射させて炉内に吹き
込むことにある。このような高速流の酸素富化ガス又は
純酸素を用いることにより、速度減衰が少なく、高濃度
を維持した酸素ガス流が、レースウェイ内部まで到達す
るので、結果的に高温領域が広がると共に、酸化性のガ
ス（Ｏ2、ＣＯ2）が、鳥の巣形成領域まで効率的に到達
し得ることを見出した。The present inventors have conducted intensive studies in order to use the above idea as an effective blast furnace operating technique for suppressing the formation of bird's nests, and have obtained the following findings. That is, while preventing the temperature of the bird's nest formation area near the back of the raceway from decreasing,
It is possible to simultaneously exert an effect on both actively raising the temperature in the region and burning the coke particles (or coke powder) in the region more actively than in the normal operation state. As a method, it was found that the effect was remarkably exhibited by the following method, and that the control operation was easy and excellent. The point of the method is that, in addition to the pulverized coal injection lance, an oxygen-enriched gas or pure oxygen injection nozzle is inserted through the blow pipe peripheral wall in accordance with the pulverized coal injection lance. At the time of pulverized coal injection, oxygen-enriched gas or pure oxygen is injected from a nozzle at a flow rate of 1.5 times or more the flow velocity at the tuyere tip of hot air that is blown from a blow pipe into a blast furnace and blown into the furnace. It is in. By using such a high-speed flow of oxygen-enriched gas or pure oxygen, the velocity decay is small, and the oxygen gas flow maintaining a high concentration reaches the inside of the raceway, so that the high-temperature region is widened as a result, It has been found that oxidizing gases (O 2 , CO 2 ) can efficiently reach the bird's nest forming area.

【００２４】この発明の第２は、上記知見により得られ
たものであり、その要旨は下記の通りである。即ち、請
求項６記載の発明に係る微粉炭の多量吹込みによる高炉
操業方法は、高炉の羽口からその高炉の炉内に熱風を吹
き込むために、その羽口の手前に連接して設けられたブ
ローパイプの周壁を貫通して挿入された微粉炭吹込み用
ランスを用いて、上記高炉に１８０ｋｇ／ｔ−溶銑以上
の微粉炭を吹き込む高炉の操業方法において、上記微粉
炭吹込み用ランスの他に、上記ブローパイプの周壁を貫
通して酸素富化ガス又は純酸素の吹込み用ノズルを挿入
し、その酸素富化ガス又は純酸素の吹込み用ノズルか
ら、その酸素富化ガス又は純酸素のジェットを、上記ブ
ローパイプから高炉内へ吹き込まれる熱風の上記羽口先
端における流速の１．５倍以上の速度で噴射させて、高
炉の炉内に吹き込むことに特徴を有するものである。The second aspect of the present invention has been obtained based on the above findings, and the gist is as follows. That is, the method for operating a blast furnace by injecting a large amount of pulverized coal according to the invention of claim 6 is provided in front of the tuyere in order to blow hot air from the tuyere of the blast furnace into the furnace of the blast furnace. Using a pulverized coal injection lance inserted through the peripheral wall of the blowpipe into the blast furnace, wherein the pulverized coal of 180 kg / t-hot metal or more is blown into the blast furnace. In addition, an oxygen-enriched gas or pure oxygen blowing nozzle is inserted through the peripheral wall of the blowpipe, and the oxygen-enriched gas or pure oxygen is injected from the oxygen-enriched gas or pure oxygen blowing nozzle. It is characterized in that a jet of oxygen is injected at a speed of 1.5 times or more the flow velocity of hot air blown into the blast furnace from the blow pipe at the tip of the tuyere, and is blown into the furnace of the blast furnace.

【００２５】請求項７記載の発明に係る微粉炭の多量吹
込みによる高炉操業方法は、請求項６記載の発明におい
て、上記酸素富化ガス又は純酸素のジェットを吹込む時
期を高炉の操業安定状態に応じて、当該ジェットを前記
高炉内へ吹き込む時期と吹き込まない時期とを設けるこ
とに特徴を有するものである。According to a seventh aspect of the present invention, in the blast furnace operating method by injecting a large amount of pulverized coal according to the sixth aspect of the present invention, the operation of the blast furnace is stabilized by injecting the jet of the oxygen-enriched gas or pure oxygen. According to the state, there is provided a time when the jet is blown into the blast furnace and a time when the jet is not blown.

【００２６】請求項８記載の発明に係る微粉炭の多量吹
込みによる高炉操業方法は、請求項７記載の発明におい
て、上記酸素富化ガス又は純酸素のジェットを上記高炉
の炉内へ吹き込む時期に、その酸素富化ガス又は純酸素
のジェトをその高炉の炉内への吹き込むに当たっては、
時間経過に対して間欠的にその酸素富化ガス又は純酸素
のジェトを吹き込むことに特徴を有するものである。According to the eighth aspect of the present invention, there is provided the blast furnace operating method according to the seventh aspect of the present invention, wherein the jet of the oxygen-enriched gas or pure oxygen is blown into the furnace of the blast furnace. Injecting the jet of the oxygen-enriched gas or pure oxygen into the furnace of the blast furnace,
It is characterized in that the jet of the oxygen-enriched gas or pure oxygen is intermittently blown with the passage of time.

【００２７】なお、本発明者等の熱間模型実験結果によ
れば、レースウェイ部における鳥の巣の形成が問題にな
るのは、微粉炭吹込み量がおよそ１８０ｋｇ／ｔ−溶銑
以上の場合である。従って、請求項１〜請求項５に係る
微粉炭の多量吹き込みによる高炉の操業方法は、微粉炭
を１８０ｋｇ／ｔ−溶銑以上吹き込む場合に適用するも
のとする。According to the results of the hot model experiment conducted by the present inventors, the formation of a bird's nest in the raceway becomes a problem when the pulverized coal injection amount is about 180 kg / t-hot metal or more. It is. Therefore, the method for operating a blast furnace by injecting a large amount of pulverized coal according to claims 1 to 5 is applied to a case where pulverized coal is blown at 180 kg / t-hot metal or more.

【００２８】[0028]

【発明の実施の形態】次に、この発明を、図面を参照し
ながら説明する。Next, the present invention will be described with reference to the drawings.

【００２９】［実施の形態−その１］図１に、本発明の
第１を実施する際に用いる、微粉炭吹込み用ランスのブ
ローパイプへの取付け状態の望ましい例を説明する縦断
面模式図を示す。高炉下部の羽口２に連接して設けられ
たブローパイプ３の周壁を斜めに貫通・挿入して、微粉
炭吹込み用ランス４を設け、当該ランス４から気体搬送
により微粉炭５を噴出させる。当該ランス４先端部を羽
口２近傍の所定位置に配設し、ブローパイプ３から炉内
へ送風ガスとして吹き込まれる熱風６中に当該微粉炭５
を噴出し、微粉炭５を熱風６と共に炉内に吹き込む。微
粉炭５の吹込み量は、１８０ｋｇ／ｔ−溶銑以上とし、
吹込み中その量を経時的に変化させるものとする。微粉
炭５の吹込み量（ｋｇ／ｔ−溶銑）を経時的に変化させ
ることにより、鳥の巣の形成位置を変化させてその形成
を抑制するためである。[Embodiment 1] FIG. 1 is a schematic vertical cross-sectional view illustrating a preferred example of a state in which a lance for blowing pulverized coal is attached to a blow pipe used in carrying out a first embodiment of the present invention. Is shown. A peripheral wall of a blowpipe 3 connected to the tuyere 2 at the lower part of the blast furnace is obliquely penetrated and inserted, and a pulverized coal injection lance 4 is provided. The pulverized coal 5 is ejected from the lance 4 by gas transfer. . The tip of the lance 4 is disposed at a predetermined position near the tuyere 2, and the pulverized coal 5 is introduced into the hot air 6 blown from the blow pipe 3 into the furnace as blowing gas.
And pulverized coal 5 is blown into the furnace together with hot air 6. The injection amount of pulverized coal 5 is 180 kg / t-hot metal or more,
During the blowing, the amount is changed with time. This is because the formation position of the bird's nest is changed by changing the blowing amount (kg / t-hot metal) of the pulverized coal 5 with time, thereby suppressing the formation.

【００３０】ここで、溶銑１ｔ当たりに対する微粉炭５
の吹込み量（ｋｇ／ｔ−溶銑）の経時変化、従って、出
銑比（ｔ−溶銑／ｄ／ｍ3）が一定の場合には、単位時
間当たりに微粉炭吹込み用ランス４から噴射させる微粉
炭の重量（本明細書において「微粉炭吹込み速度」とい
う。例えば、ｋｇ／分）の変化に関して、これを当該高
炉の微粉炭吹込み操業において設定された平均微粉炭吹
込み速度の５０〜１５０％の範囲内において変化させ
る。微粉炭吹込み量の変化に関しては、その上限値は１
５０％以下とする。１５０％を超える微粉炭吹込み量で
は、酸素量が不足するため、燃焼性が著しく悪化し、未
燃焼の微粉炭が大量にレースウェイ外に排出される。こ
のため、炉内で消費できずに炉頂からダストとして排出
され、コークス置換率Ｒが低下する。また、下限値は基
本的に、この上限値との平均が１００％となるように設
定すればようい。但し、これを５０％以下にすると、温
度分布の変化が大きくなり過ぎ、高炉操業の安定性が損
なわれる可能性があるので、その変化の範囲は、５０〜
１５０％の範囲内にすべきである。Here, pulverized coal 5 per ton of hot metal
Injection from the pulverized coal injection lance 4 per unit time when the injection rate of molten iron (kg / t-hot metal) changes over time, and therefore the tapping ratio (t-hot metal / d / m 3 ) is constant. With respect to the change in the weight of the pulverized coal to be pulverized (referred to as “pulverized coal injection rate” in the present specification, for example, kg / min), this is changed to the average pulverized coal injection rate set in the pulverized coal injection operation of the blast furnace. It is varied within the range of 50 to 150%. Regarding the change of pulverized coal injection amount, the upper limit is 1
50% or less. If the amount of pulverized coal injected exceeds 150%, the amount of oxygen is insufficient, so that the combustibility is significantly deteriorated, and a large amount of unburned pulverized coal is discharged out of the raceway. For this reason, it cannot be consumed in the furnace and is discharged as dust from the furnace top, and the coke replacement ratio R decreases. Further, the lower limit value may be basically set so that the average with the upper limit value is 100%. However, if this is set to 50% or less, the change in the temperature distribution becomes too large, and the stability of the blast furnace operation may be impaired.
Should be in the range of 150%.

【００３１】第１の本発明においては、更に、上記微粉
炭吹込み速度を変化させる頻度を、１分当たり１５回以
上変化させるように設定する。当該微粉炭吹込み速度の
変化頻度を、１分当たり１５回未満に少なくすると、鳥
の巣の生成・成長に対して必要なレースウェイ深度の定
常状態化が起こり易くなり、レースウェイ端部奥のコー
クス層中に灰分を多量に含んだスラグがホールドアップ
される量が増加して、通気性を阻害する鳥の巣の形成が
開始される。これに対して、上記微粉炭吹込み速度変化
の変化頻度を、１分当たり３０回超えに多くしても、レ
ースウェイ深度を経時的に変化させることによる鳥の巣
の形成抑制効果は飽和状態に達する。一方、上記微粉炭
吹込み速度の変化の頻度を１分当たり３０回超えに多く
するためには、微粉炭吹込みラインの装置の制御系を性
能強化する必要等が生じ、設備コストが上昇する。従っ
て、微粉炭吹込みランス４からの微粉炭吹込み速度を上
記所定の範囲において変化させる１分当たりの頻度は、
少なくとも１５回以上に多くすべきであり、一層望まし
くは１５〜３０回の範囲内とすべきである。In the first aspect of the present invention, the frequency of changing the pulverized coal blowing speed is set to be changed at least 15 times per minute. If the frequency of the change of the pulverized coal injection speed is reduced to less than 15 times per minute, the steady state of the raceway depth required for bird nest generation / growth is likely to occur, and the raceway end deep The amount of slag containing a large amount of ash in the coke layer of the coconut is increased and the formation of a bird's nest that inhibits air permeability is started. On the other hand, even if the frequency of the change in the pulverized coal injection speed is increased to more than 30 times per minute, the bird's nest formation suppression effect by changing the raceway depth over time is saturated. Reach On the other hand, in order to increase the frequency of the change of the pulverized coal injection speed to more than 30 times per minute, it is necessary to enhance the performance of the control system of the apparatus of the pulverized coal injection line, thereby increasing equipment costs. . Therefore, the frequency per minute for changing the pulverized coal injection speed from the pulverized coal injection lance 4 in the above-mentioned predetermined range is as follows:
It should be at least as many as 15 times or more, more preferably in the range of 15 to 30 times.

【００３２】微粉炭吹込み用ランス４について、１本の
ブローパイプ３に対して２本設けた例を図１に示した。
但し、この微粉炭吹込み用ランス４のブローパイプ（符
号：３）１本に対する装備本数は、微粉炭吹込み比（Ｐ
ＣＲ）として１８０ｋｇ／ｔ−溶銑以上の微粉炭吹き込
み能力を有し、上述した微粉炭吹込み速度の変化範囲及
びその速度変化の頻度を満たす限り、２本に限定する必
要はない。また、当該微粉炭吹込み用ランス４の方式な
いし構造は、常用の単管構造ランス、同心２重管構造ラ
ンス、あるいは多孔ノズル構造ランス、その他の微粉炭
吹込み可能なランス等いずれでもよく、また、適宜水冷
等による冷却ジャケットを付帯させたり、耐火材料で被
覆したりするとよい。FIG. 1 shows an example in which two lances 4 for blowing pulverized coal are provided for one blow pipe 3.
However, the number of the pulverized coal injection lances 4 for one blow pipe (symbol: 3) is determined by the pulverized coal injection ratio (P
CR) does not need to be limited to two as long as it has a pulverized coal injection capability of 180 kg / t-hot metal or more and satisfies the change range of the pulverized coal injection speed and the frequency of the speed change described above. Further, the method or structure of the pulverized coal injection lance 4 may be any of a conventional single pipe lance, a concentric double pipe lance, a multi-hole nozzle lance, and other lances capable of injecting pulverized coal. Further, a cooling jacket by water cooling or the like may be provided as appropriate, or may be covered with a refractory material.

【００３３】この発明において微粉炭を高炉の炉内に吹
き込むに当り、ブローパイプから送風される熱風中の２
１％程度の酸素だけでは、微粉炭の燃焼性が十分ではな
いので、微粉炭の燃焼を促進するために別途酸素ガスを
微粉炭流れに混入する。この酸素ガスの微粉炭への混入
方式として、微粉炭吹込み用ランスから酸素ガスを噴射
したり、それができない構造のランスを使用する場合に
は、ブローパイプの周壁に、別途この酸素ガスを添加し
得るノズルを挿入し装備してもよい。あるいは、添加用
酸素ガスの一部を空気中に予め加えた酸素富化空気を送
風用熱風として使用してもよい。In the present invention, when the pulverized coal is blown into the furnace of the blast furnace, the hot coal blown from the blowpipe is blown into the blast furnace.
Oxygen of only about 1% does not provide sufficient pulverized coal combustibility, so oxygen gas is separately mixed into the pulverized coal stream to promote the combustion of pulverized coal. As a method for mixing oxygen gas into pulverized coal, when oxygen gas is injected from a pulverized coal injection lance or when a lance with a structure that does not allow it is used, this oxygen gas is separately added to the peripheral wall of the blow pipe. A nozzle that can be added may be inserted and equipped. Alternatively, oxygen-enriched air in which a part of oxygen gas for addition is added in advance to air may be used as hot air for blowing.

【００３４】特に、微粉炭吹込み用ランスとして、同心
２重管構造ランスを用い、内管から微粉炭を吹き込み、
その内管と外管との間隙から酸素富化ガス又は純酸素を
吹き込む方式にすると、微粉炭の燃焼性が向上して望ま
しい。更に、その内管と外管との間隙から噴出させる酸
素富化ガス又は純酸素の吹込み速度を、内管から噴出さ
せる微粉炭の吹込み速度の変化に同調させて変化させ
る。このように両者の吹込み速度を同調させることによ
り、微粉炭の吹込み速度のみをその平均吹込み速度以上
に上昇させる過程で生じる微粉炭の燃焼性低下を防止す
ることができるからである。例えば、微粉炭吹込み比が
２００ｋｇ／ｔ−溶銑である平均微粉炭吹込み速度で操
業中の高炉において、当該平均微粉炭吹込み速度の１５
０％である３００ｋｇ／ｔ−溶銑の微粉炭吹込み速度で
吹込みを行なうときには、ブローパイプによる送風の熱
風中の酸素流量と、この場合の微粉炭を完全燃焼させる
のに必要な理論酸素流量との比が著しく低下し、微粉炭
燃焼時の酸素過剰率が著しく低減して、微粉炭の燃焼性
が低下する。そこで、同心２重管構造ランスから吹き込
む酸素富化ガス又は純酸素の流量も、その平均流量の１
５０％に増やして、微粉炭粒子周りの酸素濃度を高め、
微粉炭の燃焼性低下を抑制する。ここで、上記の通り、
微粉炭吹込み速度の上昇と同調させて微粉炭の燃焼に必
要な十分な流量の酸素を供給する限り、酸素富化ガス中
の酸素濃度は特に限定しなくてもよい。酸素富化ガスと
して、例えば、２１％酸素濃度の空気から、純酸素に近
い酸素濃度のガスであってもよい。また、微粉炭燃焼用
酸素の内、ブローパイプによる送風中酸素分の流量に対
する上記同心２重管から吹き込まれる酸素富化ガス中酸
素分の流量又は純酸素流量の付加分の全量を、必ずしも
同心２重管から吹き込む必要はなく、上記付加酸素分の
一部を同心２重管ランスから吹き込み、残部をブローパ
イプによる送風中に付加して酸素富化空気を送風しても
よい。なお、同心２重管ランスから吹き込む酸素富化ガ
スとしては、酸素富化空気、あるいは酸素ガスと窒素そ
の他のガスとの混合ガスのいずれでもよい。また、酸素
富化ガス又は純酸素の吹込み速度の変化のパターンは、
微粉炭吹込み速度の変化のパターンに合わせて、段階状
変化、パルス状変化、あるいはサインカーブ状変化等周
期的に変化させ得るパターンである限り、いずれを採用
してもよい。また、送風中に酸素を付加して酸素富化空
気を送風する場合の、熱風への酸素吹き込み速度の変化
のパターンについても、上述した酸素富化ガス又は純酸
素の吹込み速度の変化のパターンに準じる。In particular, a concentric double-pipe lance is used as a pulverized coal injection lance, and pulverized coal is blown from an inner pipe.
It is desirable to blow oxygen-enriched gas or pure oxygen through the gap between the inner pipe and the outer pipe, because the pulverized coal has improved flammability. Further, the blowing speed of the oxygen-enriched gas or pure oxygen ejected from the gap between the inner tube and the outer tube is changed in synchronization with the change of the blowing speed of the pulverized coal ejected from the inner tube. By synchronizing the two blowing speeds in this way, it is possible to prevent a decrease in the flammability of the fine coal which occurs in the process of raising only the blowing speed of the fine coal to the average blowing speed or more. For example, in a blast furnace operating at an average pulverized coal injection rate with a pulverized coal injection rate of 200 kg / t-hot metal, the average pulverized coal injection rate is 15 kg.
When blowing at a pulverized coal injection rate of 300 kg / t-hot metal, which is 0%, the oxygen flow rate in the hot air blown by the blow pipe and the theoretical oxygen flow rate required to completely burn the pulverized coal in this case , The excess oxygen ratio during pulverized coal combustion is significantly reduced, and the pulverized coal combustibility is reduced. Therefore, the flow rate of the oxygen-enriched gas or pure oxygen blown from the concentric double-pipe lance is also 1% of the average flow rate.
Increase to 50% to increase the oxygen concentration around the pulverized coal particles,
Suppress the decrease in flammability of pulverized coal Here, as described above,
The oxygen concentration in the oxygen-enriched gas does not need to be particularly limited as long as a sufficient flow of oxygen necessary for combustion of the pulverized coal is supplied in synchronization with the increase in the pulverized coal injection speed. As the oxygen-enriched gas, for example, a gas having an oxygen concentration close to pure oxygen from air having an oxygen concentration of 21% may be used. Further, of the oxygen for pulverized coal combustion, the flow rate of oxygen in the oxygen-enriched gas blown from the concentric double pipe or the total flow rate of pure oxygen flow to the flow rate of oxygen in the blown pipe by the blow pipe is not necessarily concentric. It is not necessary to blow the oxygen-enriched air by blowing a part of the added oxygen from the concentric double-tube lance, and adding the remaining portion to the air blown by the blowpipe. The oxygen-enriched gas blown from the concentric double tube lance may be oxygen-enriched air or a mixed gas of oxygen gas and nitrogen or another gas. In addition, the pattern of the change of the blowing rate of the oxygen-enriched gas or pure oxygen,
Any pattern may be employed as long as it is a pattern that can be changed periodically, such as a stepwise change, a pulse-like change, or a sine curve-like change, in accordance with the pattern of the pulverized coal injection speed change. In addition, in the case of blowing oxygen-enriched air by adding oxygen during blowing, the change pattern of the blowing rate of oxygen-enriched gas or pure oxygen as described above is also used as the pattern of changing the blowing rate of oxygen into hot air. According to.

【００３５】［実施の形態−その２］図２に、本発明の
第２を実施するに際して用いる、微粉炭吹込み用ランス
並びに酸素富化ガス又は純酸素吹込み用ノズルの、ブロ
ーパイプへの取付け状態の望ましい例を説明する縦断面
模式図を示す。高炉下部の羽口２に連接して設けられた
ブローパイプ３の周壁を斜めに貫通・挿入して、微粉炭
吹込み用ランス４を設ける。当該ランス４から気体搬送
により微粉炭５を噴出させる。当該ランス４先端部は羽
口２近傍の所定位置に配設し、ブローパイプ３から炉内
へ送風ガスとして吹き込まれる熱風６中に当該微粉炭５
を噴出し、微粉炭５を熱風６と共に炉内に吹き込む。微
粉炭５の吹込み量は、１８０ｋｇ／ｔ−溶銑以上とす
る。[Embodiment 2] FIG. 2 shows that a lance for pulverized coal injection and a nozzle for injecting oxygen-enriched gas or pure oxygen used for carrying out the second embodiment of the present invention are connected to a blow pipe. FIG. 2 is a schematic vertical cross-sectional view illustrating a desirable example of an attached state. A lance 4 for pulverized coal injection is provided by obliquely penetrating and inserting a peripheral wall of a blow pipe 3 provided in connection with the tuyere 2 at the lower part of the blast furnace. The pulverized coal 5 is ejected from the lance 4 by gas transfer. The tip of the lance 4 is disposed at a predetermined position near the tuyere 2, and the pulverized coal 5 is introduced into the hot air 6 blown from the blow pipe 3 into the furnace as blowing gas.
And pulverized coal 5 is blown into the furnace together with hot air 6. The injection amount of the pulverized coal 5 is set to 180 kg / t-hot metal or more.

【００３６】一方、上記微粉炭吹込み用ランス４の他に
更に、ブローパイプ３の周壁を斜めに貫通・挿入して、
酸素富化ガス又は純酸素の吹込み用ノズル１３を設け
る。当該ノズル１３は、羽口２先における熱風の流速の
１．５倍以上の流速で当該酸素富化ガス又は純酸素１４
ａを噴射能力を有するものであれば、その型式や構造等
を特に限定する必要はない。例えば、単管ノズル、先端
にラバールノズルを備えたノズル等が適する。また、そ
の装着に当たっては、当該ノズル１３から噴射される酸
素富化ガス又は純酸素のジェット１４の方向が、ブロー
パイプ３内壁や羽口２内壁、あるいは微粉炭流れに衝突
しないように、レースウェイ７奥端部に向けて調節する
ことが重要である。そして、そのノズル１３から当該酸
素富化ガス又は純酸素のジェット１４を噴出させる。On the other hand, besides the pulverized coal blowing lance 4, the peripheral wall of the blow pipe 3 is obliquely penetrated and inserted.
A nozzle 13 for blowing oxygen-enriched gas or pure oxygen is provided. The nozzle 13 is provided with the oxygen-enriched gas or pure oxygen
It is not necessary to particularly limit the type, structure, and the like of a as long as it has an injection capability. For example, a single tube nozzle, a nozzle having a Laval nozzle at the tip, and the like are suitable. In addition, in mounting the raceway, the direction of the jet 14 of oxygen-enriched gas or pure oxygen injected from the nozzle 13 does not collide with the inner wall of the blow pipe 3 or the inner wall of the tuyere 2 or the pulverized coal flow. It is important to adjust toward the back end. Then, a jet 14 of the oxygen-enriched gas or pure oxygen is ejected from the nozzle 13.

【００３７】酸素富化ガス又は純酸素のジェット１４の
流速を、ブローパイプ３から高炉内へ吹き込む上記熱風
６の羽口２先端における流速の１．５倍以上の速度で噴
射させて、その酸素富化ガス又は純酸素のジェット１４
を高炉内に吹き込む。このように、酸素富化ガス又は純
酸素のジェット１４を、熱風６の羽口２先端における流
速の１．５倍以上の流速で噴射させると、酸素をレース
ウェイ７内部に一層多く到達させ得るので、結果的に酸
化性ガス（Ｏ2、ＣＯ2）をレースウェイ奥までより多く
供給して、その領域のコークスを一層多く燃焼させると
同時に、高温域がより奥まで広がるので、鳥の巣が存在
する領域の温度を上昇させることができる。しかし、当
該ジェット１４の速度がそれよりも遅くなると、酸素富
化ガス又は純酸素のジェット１４は熱風６と急激に混合
し、流速が減衰して、レースウェイ７内部まで十分に到
達しなくなり、鳥の巣の温度を十分に上昇させる効果が
期待できなくなる。そのために鳥の巣中のスラグの粘性
低下が不十分となってそのホールドアップ量を低減させ
ることが困難となり、そのために鳥の巣の形成抑制がで
きなくなる。The jet of the jet 14 of oxygen-enriched gas or pure oxygen is jetted at a speed of 1.5 times or more the flow speed of the hot air 6 blown from the blow pipe 3 into the blast furnace at the tip of the tuyere 2. Jet 14 of enriched gas or pure oxygen
Into the blast furnace. As described above, when the jet 14 of the oxygen-enriched gas or the pure oxygen is jetted at a flow rate of 1.5 times or more of the flow rate of the hot air 6 at the tip of the tuyere 2, more oxygen can reach the inside of the raceway 7. As a result, more oxidizing gas (O 2 , CO 2 ) is supplied to the far side of the raceway to burn more coke in the area, and at the same time, the high temperature area spreads further, so that the bird's nest Can increase the temperature of the region where is present. However, when the speed of the jet 14 becomes slower than that, the jet 14 of oxygen-enriched gas or pure oxygen rapidly mixes with the hot air 6, the flow velocity is attenuated, and it does not sufficiently reach the inside of the raceway 7, The effect of sufficiently raising the temperature of the bird's nest cannot be expected. For this reason, the viscosity of the slag in the bird's nest is insufficiently reduced, and it is difficult to reduce the hold-up amount. As a result, formation of the bird's nest cannot be suppressed.

【００３８】この酸素富化ガス又は純酸素のジェット１
４の高炉内への吹込みを行なう時期は、当該高炉の操業
条件や炉の安定状態に応じて、これを吹き込む時期と吹
き込まない時期とを設けることが望ましい。即ち、微粉
炭吹込みの高炉操業において、上述した条件下における
酸素富化ガス又は純酸素のジェット１４の噴射は、間欠
的に操作をすることが望ましい。即ち、当該酸素富化ガ
ス又は純酸素のジェット１４の上述した吹込み操作は、
例えば、特に、炉下部通気性が良好な時期に行なっても
その効果が十分に発揮されず、酸素のコストが嵩むだけ
である。従って、そのジェット１４の炉内への吹込み
は、高炉の炉下部通気性が悪化してきたと判断されると
き等、高炉の操業安定状態に応じて、間欠的に行なうこ
とが望ましい。例えば、高炉炉下部の通気抵抗が上昇し
ている時期に１日に数時間、間欠的に吹き込むだけで十
分である。This oxygen-enriched gas or pure oxygen jet 1
It is desirable to set the timing of blowing into the blast furnace 4 according to the operating conditions of the blast furnace or the stable state of the furnace, and the timing of blowing the blast furnace. That is, in the blast furnace operation in which pulverized coal is injected, it is desirable that the jet of the jet 14 of the oxygen-enriched gas or the pure oxygen under the above-described conditions be operated intermittently. That is, the above-described blowing operation of the jet 14 of the oxygen-enriched gas or pure oxygen is performed as follows.
For example, the effect is not sufficiently exhibited even when the gas permeability in the lower part of the furnace is good, and only the cost of oxygen increases. Therefore, it is desirable that the jet 14 be blown into the furnace intermittently according to the stable operation of the blast furnace, for example, when it is determined that the permeability of the lower part of the blast furnace has deteriorated. For example, it is sufficient to intermittently blow air for several hours a day when the ventilation resistance in the lower part of the blast furnace is rising.

【００３９】また、酸素富化ガス又は純酸素のジェット
１４による吹込み酸素量は、その効果を確認しながら調
整することが望ましいが、ブローパイプ３から吹き込ま
れる送風に対する酸素富化率換算で、１〜３％の範囲内
の酸素量に相当する酸素流量を吹き込めば、その効果が
十分発揮される。それが１％より少なくては、その効果
が十分に発揮されず、一方、３％よりも多くても、その
効果は飽和する傾向にあるので、通常操業においては経
済上は３％を上限として差し支えない。It is desirable to adjust the amount of oxygen blown by the jet 14 of oxygen-enriched gas or pure oxygen while confirming its effect. If the oxygen flow rate corresponding to the oxygen amount in the range of 1 to 3% is blown, the effect is sufficiently exhibited. If it is less than 1%, the effect is not sufficiently exhibited, while if it is more than 3%, the effect tends to saturate. No problem.

【００４０】なお、当該酸素富化ガス又は純酸素のジェ
ット１４による酸素吹込み時期における当該酸素の吹込
み速度、従って、操業中におけるように、当該使用中酸
素のノズル１３を他のノズルと交換できない場合には、
当該酸素のノズル１３の出口における流速は、当該流速
が羽口２の先端における熱風の流速の１．５倍に確保し
ておく限り、特に所定の範囲内の周期で変化させる必要
はない。酸素富化ガス又は純酸素のジェット１４の本発
明における吹込み目的からわかるように、鳥の巣が成長
を開始する状況を検出しながら、適切なタイミングで鳥
の巣領域に対して酸素を効率よく供給することが重要だ
からである。なお、当該酸素吹込み時期の一部又は全期
間において、実施の形態−その１において述べたよう
に、微粉炭吹込み速度を適切な周期の範囲内において変
化させて、レースウェイ深度の位置を前後に変化させる
ことにより、鳥の巣の形成を抑制するという効果も併せ
ねらう場合には、酸素富化ガス又は純酸素の吹込み用ノ
ズル１３出口における当該酸素富化ガス又は純酸素のジ
ェット１４の流速が、高炉内へ吹き込まれる熱風６の羽
口２先端における流速の１．５倍以上の速度を確保する
ことが必要であり、これを前提条件として、上記酸素富
化ガス又は純酸素１４ａの吹込み速度を、段階状変化、
パルス状変化あるいはサインカーブ状変化等いずれのパ
ターンに変化させても、目的とする作用効果をある程度
発揮させることができる。It should be noted that the oxygen blowing rate at the time of oxygen injection by the oxygen-enriched gas or pure oxygen jet 14 and, therefore, the nozzle 13 for the used oxygen is replaced with another nozzle as during operation. If not,
The flow rate of the oxygen at the outlet of the nozzle 13 does not need to be changed in a cycle within a predetermined range, as long as the flow rate is ensured to be 1.5 times the flow rate of the hot air at the tip of the tuyere 2. As can be seen from the purpose of the present invention of jetting a jet 14 of oxygen-enriched gas or pure oxygen, while detecting the situation where the bird's nest begins to grow, the oxygen is efficiently released to the bird's nest area at the appropriate time. It is important to supply well. Note that, during a part or the entire period of the oxygen injection period, as described in the embodiment 1 by changing the pulverized coal injection speed within an appropriate cycle range, the position of the raceway depth is changed. When the effect of suppressing the bird's nest formation is also intended by changing back and forth, the oxygen-enriched gas or pure oxygen jet 14 at the outlet of the oxygen-enriched gas or pure oxygen blowing nozzle 13 is provided. It is necessary to ensure that the flow velocity of the hot air 6 blown into the blast furnace is 1.5 times or more as high as the flow velocity at the tip of the tuyere 2. Change the blowing speed
Regardless of the pattern, such as a pulse-like change or a sine-curve change, the intended operation and effect can be exhibited to some extent.

【００４１】[0041]

【実施例】この発明を実施例により更に詳細に説明す
る。The present invention will be described in more detail with reference to examples.

【００４２】内容積４８２８ｍ3 、羽口数４０本を備え
た高炉において、下記［試験１］〜［試験４］の微粉炭
多量吹込みによる操業試験を、表１に示す操業条件をベ
ースとして行なった。また、表２に、これらのすべての
試験で使用した微粉炭の成分組成を示す。吹込みに使用
した微粉炭は、その灰分含有率が７．５ｍａｓｓ％であ
り、その粒度が−７４μｍの粒子が８０ｍａｓｓ％以上
になるように粉砕したものである。そして、ここで行な
った操業試験は、［試験１］及び［試験２］において、
この発明の第１の実施形態の望ましい試験操業を行な
い、［試験３］及び［試験４］において、この発明の第
２の実施形態の望ましい試験操業をおこなった。こうし
て、本発明の範囲内に属する微粉炭の多量吹込みによる
高炉操業方法である実施例１〜実施例９、及び本発明の
範囲外である微粉炭の多量吹込みによる高炉操業方法で
ある比較例１〜比較例７の各試験を行なった。In a blast furnace having an inner volume of 4828 m 3 and a number of tuyeres of 40, operation tests of the following [Test 1] to [Test 4] by injecting a large amount of pulverized coal were performed based on the operation conditions shown in Table 1. . Table 2 shows the component compositions of the pulverized coal used in all of these tests. The pulverized coal used for the blowing was pulverized so that the ash content was 7.5 mass% and the particles having a particle size of -74 μm became 80 mass% or more. The operation test performed here was performed in [Test 1] and [Test 2].
The desirable test operation of the first embodiment of the present invention was performed, and the desirable test operation of the second embodiment of the present invention was performed in [Test 3] and [Test 4]. Thus, Examples 1 to 9 which are blast furnace operating methods by injecting a large amount of pulverized coal belonging to the scope of the present invention, and comparisons which are blast furnace operating methods by injecting a large amount of pulverized coal which are not within the scope of the present invention Each test of Example 1 to Comparative Example 7 was performed.

【００４３】[0043]

【表１】 [Table 1]

【００４４】[0044]

【表２】 [Table 2]

【００４５】［試験１］図１に示した本発明の第１の実
施形態で説明した微粉炭吹込み用ランスの取付け方法及
び微粉炭供給方法により、微粉炭の多量吹込み操業試験
を行なった。即ち、高炉の各羽口２に連接するブローパ
イプ３の周壁を貫通させて、常用の単管構造の微粉炭吹
込み用ランス４を各羽口２に２本ずつ取り付け、これよ
り平均微粉炭吹込み比２００ｋｇ／ｔ−溶銑の微粉炭を
高炉炉内に吹き込んだ。[Test 1] A large coal pulverized coal blowing operation test was conducted by the method of mounting the pulverized coal injection lance and the method of supplying pulverized coal described in the first embodiment of the present invention shown in FIG. . That is, two lances 4 for injecting pulverized coal having a normal single pipe structure are attached to each tuyere 2 by penetrating the peripheral wall of the blowpipe 3 connected to each tuyere 2 of the blast furnace, and the average pulverized coal is Pulverized coal having a blowing ratio of 200 kg / t-hot metal was blown into the blast furnace.

【００４６】本発明の範囲内の実施例１においては、平
均２００ｋｇ／ｔ−溶銑の微粉炭を、最大３００ｋｇ／
ｔ−溶銑と最低１００ｋｇ／ｔ−溶銑との範囲内で変化
させた。この微粉炭吹込み量の時間経過に対する変化、
従って微粉炭吹込み速度の変化がサインカーブとなるよ
うにその吹込み量を制御し、更にそのサインカーブの振
動数を２５回／分となるよにして炉内に吹き込んだ。な
お、本発明の範囲外の比較例１においては、微粉炭吹込
み比２００ｋｇ／ｔ−溶銑で、一定量の微粉炭吹込み速
度で微粉炭を炉内に吹き込んだ。図３に、実施例１のサ
インカーブに基づく微粉炭吹込み比の時間経過に対する
変化のパターン、及び比較例１における微粉炭吹込み比
一定値の場合の微粉炭吹込みパターンを図示した。In Example 1 within the scope of the present invention, pulverized coal with an average of 200 kg / t-hot metal was supplied at a maximum of 300 kg / t.
It was varied within the range of t-hot metal and at least 100 kg / t-hot metal. Change in the amount of pulverized coal injected over time,
Therefore, the amount of pulverized coal was controlled so that the change in the pulverized coal injection speed was a sine curve, and the sine curve was blown into the furnace at a frequency of 25 times / minute. In Comparative Example 1 outside the scope of the present invention, pulverized coal was blown into the furnace at a pulverized coal injection rate of 200 kg / t-hot metal at a fixed pulverized coal injection rate. FIG. 3 illustrates a change pattern of the pulverized coal injection ratio with time based on the sine curve of Example 1 and a pulverized coal injection pattern in Comparative Example 1 when the pulverized coal injection ratio is constant.

【００４７】実施例１及び比較例１の高炉操業試験にお
ける鳥の巣の生成・成長状況を推定し、本発明の効果を
評価する方法として、実施例１及び比較例１の試験操業
期間中、ブローパイプ３への熱風送風圧力（この明細書
において「熱風送風圧」という）と、羽口２の軸線から
上方７ｍ位置での高炉内壁近傍における圧力（この明細
書において「ボッシュ内圧」という）との差圧ΔＰの経
時変化を測定した。図４に、実施例１及び比較例１の各
試験操業期間中の代表的時期における熱風送風圧とボッ
シュ内圧との差圧ΔＰの経時変化を示す。熱風送風圧と
ボッシュ内圧との差圧ΔＰの水準及びその差圧ΔＰの変
動の大きさについて、微粉炭吹込み速度を上記サインカ
ーブに従って変化させた実施例１と、微粉炭吹込み速度
を変化させなかった比較例１とを比較すると、実施例１
は比較例１よりも当該差圧ΔＰが小さくなり、しかもそ
の差圧ΔＰの変動が著しく小さくなり、ほぼ解消してい
る。As a method for estimating the state of bird nest formation and growth in the blast furnace operation test of Example 1 and Comparative Example 1, and evaluating the effect of the present invention, the method of Example 1 and Comparative Example 1 The hot air blowing pressure to the blow pipe 3 (referred to as “hot air blowing pressure” in this specification) and the pressure near the inner wall of the blast furnace at a position 7 m above the axis of the tuyere 2 (referred to as “Bosch internal pressure” in this specification). The change with time of the differential pressure ΔP was measured. FIG. 4 shows a temporal change of the differential pressure ΔP between the hot air blowing pressure and the Bosch internal pressure at a representative time during the test operation periods of Example 1 and Comparative Example 1. With respect to the level of the pressure difference ΔP between the hot air blowing pressure and the Bosch internal pressure and the magnitude of the fluctuation of the pressure difference ΔP, Example 1 in which the pulverized coal injection speed was changed according to the above sine curve, and the pulverized coal injection speed was changed. In comparison with Comparative Example 1 which was not made, Example 1
The differential pressure ΔP is smaller than that of the comparative example 1, and the fluctuation of the differential pressure ΔP is significantly reduced, which is almost eliminated.

【００４８】この試験結果より、実施例１においては、
レースウェイ深度が変動せしめられ、鳥の巣に対して振
動やせん断力等機械力が作用せしめられた結果、鳥の巣
内のスラグのホールドアップ量が減少し、しかも鳥の巣
の生成・成長のための条件の定常状態化への到達が阻止
された結果、鳥の巣の厚みが大幅に減少した結果、炉下
部の通気性が改善されたものと推定される。From this test result, in Example 1,
The raceway depth fluctuated and the bird's nest was subjected to mechanical forces such as vibration and shear force, resulting in a reduction in the amount of slag held up in the bird's nest and the formation and growth of the bird's nest As a result, the bird's nest thickness was significantly reduced, resulting in improved air permeability at the lower part of the furnace.

【００４９】次に、実施例１及び比較例１の試験操業時
における、レースウェイ奥の領域の充填状態の差を把握
するために、炉芯ゾンデ及び光ファイバーを用いて、レ
ースウェイ及び充填構造の推定をした。図５に、各試験
操業中に、炉芯ゾンデ１５をブローパイプ３を経由して
高炉羽口２からレースウェイ７奥に挿入する状況を説明
する、縦断面模式図を示す。炉芯ゾンデ１５のレースウ
ェイ７内部への挿入推力の変化を測定すると共に、光フ
ァイバースコープでレースウェイ７内部を直接観察し
た。Next, in order to grasp the difference in the filling state in the area behind the raceway during the test operation of Example 1 and Comparative Example 1, the raceway and the filling structure were measured using a furnace core sonde and an optical fiber. Estimated. FIG. 5 is a schematic vertical cross-sectional view for explaining a situation in which the furnace core sonde 15 is inserted from the blast furnace tuyere 2 to the back of the raceway 7 via the blow pipe 3 during each test operation. The change in the thrust for inserting the core mandrel 15 into the raceway 7 was measured, and the inside of the raceway 7 was directly observed with an optical fiber scope.

【００５０】図６に、羽口先端から前方への距離に対す
る、炉芯ゾンデの挿入推力測定結果を示す。比較例１に
おいては、羽口先端から約１ｍ付近から挿入推力が増加
し始めていることから、レースウェイ深さは約１ｍであ
ること、更にそれより先において挿入推力が急激な増加
を続けていることから、レースウェイ奥に充填密度の高
い領域が存在することを示唆している。一方、この領域
を光ファイバースコープで直接観察をした結果、これは
多量のスラグをホールドアップしたコークス充填層、即
ち、鳥の巣であることが検証された。更に、羽口先端か
ら約２．３ｍより前方においては、必要な挿入推力が設
備能力上限に達して、これ以上挿入することができなか
った。これに対して、実施例１においては、レースウェ
イ深さは比較例１の場合に比べてやや拡大した。また、
それより前方における挿入推力の増加程度は、比較例１
の場合に比べて大巾に緩和された。一方、この領域の光
ファイバースコープによる直接観察でも、レースウェイ
奥におけるコークス充填層にホールドアップされたスラ
グの量は、比較例１と比べて大幅に減少していることが
わかった。FIG. 6 shows the results of measurement of the insertion thrust of the furnace core sonde with respect to the distance from the tuyere tip to the front. In Comparative Example 1, since the insertion thrust starts to increase from about 1 m from the tuyere tip, the raceway depth is about 1 m, and further ahead, the insertion thrust continues to increase sharply. This suggests that there is a region with high packing density at the back of the raceway. On the other hand, as a result of directly observing this region with an optical fiber scope, it was verified that this was a coke packed layer holding a large amount of slag, that is, a bird's nest. Furthermore, at a position forward of about 2.3 m from the tuyere tip, the required insertion thrust reached the upper limit of the facility capacity, and no further insertion was possible. On the other hand, in Example 1, the raceway depth was slightly larger than that in Comparative Example 1. Also,
The degree of increase in the insertion thrust in front of that is shown in Comparative Example 1.
It was greatly relaxed compared to the case. On the other hand, direct observation of this region with an optical fiber scope also revealed that the amount of slag held up in the coke packed layer at the back of the raceway was significantly reduced as compared with Comparative Example 1.

【００５１】以上の結果より、本発明の第１の実施形態
による微粉炭の多量吹込みによる高炉の操業方法によれ
ば、レースウェイ奥における鳥の巣の生成・成長は、従
来の微粉炭の多量吹込みによる高炉の操業方法における
よりも大幅に抑制され、その結果、炉下部通気性が著し
く改善されることがわかる。According to the above results, according to the method for operating the blast furnace by injecting a large amount of pulverized coal according to the first embodiment of the present invention, the generation and growth of the bird's nest at the back of the raceway is the same as the conventional pulverized coal. It can be seen that the amount is greatly suppressed as compared with the operation method of the blast furnace by a large amount of injection, and as a result, the permeability at the lower part of the furnace is significantly improved.

【００５２】［試験２］試験１と同一の、内容積４８２
８ｍ3 、羽口数４０本を備えた高炉において、表１に示
した操業条件をベースとして、微粉炭の多量吹込み操業
試験を行なった。[Test 2] The same internal volume 482 as in Test 1
In a blast furnace provided with 8 m 3 and 40 tuyeres, a large-volume pulverized coal injection operation test was performed based on the operation conditions shown in Table 1.

【００５３】微粉炭吹込み用ランスを試験１と同じよう
に、高炉の各羽口のブローパイプに２本ずつ取り付け、
また同じ送給方法で吹き込んだ。但し、微粉炭吹込み用
ランスとしては、同心２重管構造のものを使用し、内管
から微粉炭を、内管と外管との間隙から酸素濃度を５０
ｖｏｌ％に調製した酸素富化空気、即ち、純酸素と空気
との混合ガスを吹き込んだ。この微粉炭吹込み用ランス
から吹き込んだ純酸素の量は、送風中への酸素富化率に
換算して、１．５％に相当する。As in Test 1, two lances for pulverized coal injection were attached to the blow pipes of each tuyere of the blast furnace.
It was blown in the same way. However, a concentric double pipe structure lance is used as the pulverized coal injection lance, and pulverized coal is supplied from the inner pipe and oxygen concentration is set to 50 from the gap between the inner pipe and the outer pipe.
The oxygen-enriched air adjusted to vol%, that is, a mixed gas of pure oxygen and air was blown. The amount of pure oxygen blown from the pulverized coal blowing lance is equivalent to 1.5% in terms of the oxygen enrichment rate during blowing.

【００５４】一方、内管から平均２００ｋｇ／ｔ−溶銑
の微粉炭を吹き込み、最小吹込み量を２００×０．５＝
１００ｋｇ／ｔ−溶銑、最大吹込み量を２００×１．５
＝３００ｋｇ／ｔ−溶銑とし、この間を吹込み経過時間
に対して吹込み量がサインカーブを描くように制御して
吹込む。その際、酸素富化空気もこれに同調させるが、
このうち純酸素量についてはその吹込み量を、送風中へ
の酸素富化率に換算して、最小吹込み量１．５％×０．
５、最大吹込み量１．５％×１．５、即ち、０．７５〜
２．２５％の間の酸素量を、吹込み時間に対してサイン
カーブで変化させた。純酸素と混合する空気量は酸素富
化空気中の酸素濃度が５０ｖｏｌ％一定になるように同
様に変化させた。On the other hand, pulverized coal of an average of 200 kg / t-hot metal was blown from the inner pipe, and the minimum blowing amount was 200 × 0.5 =
100 kg / t-hot metal, maximum injection volume 200 × 1.5
= 300 kg / t-hot metal, and during this time, the amount of injection is controlled such that the injection amount draws a sine curve with respect to the elapsed time of injection. At this time, the oxygen-enriched air is synchronized with this,
Of the pure oxygen amount, the blowing amount is converted to the oxygen enrichment rate during the blowing, and the minimum blowing amount is 1.5% × 0.1.
5, maximum blowing amount 1.5% × 1.5, that is, 0.75
The oxygen content between 2.25% was varied in a sine curve with respect to the blowing time. The amount of air mixed with pure oxygen was similarly changed so that the oxygen concentration in the oxygen-enriched air was constant at 50 vol%.

【００５５】こうして設定された微粉炭吹込み速度及び
酸素富化空気の上記サインカーブによる変化の振動数
を、毎分５回〜４０回の間で変化させた。但し、当該振
動数は、試験操業毎に次の通り設定し、その他に、微粉
炭吹込み速度を２００ｋｇ／ｔ−溶銑の一定とした場合
も試験した。即ち、 比較例２：０回／分、 比較例３：５回／分、 比較例４：１０回／分、 実施例２：１５回／分、 実施例３：２０回／分、 実施例４：２５回／分、 実施例５：３０回／分、 実施例６：３５回／分、及び、 実施例７：４０回／分、 の試験を行なった。The thus set pulverized coal blowing rate and the frequency of the change of the oxygen-enriched air by the sine curve were changed between 5 and 40 times per minute. However, the vibration frequency was set as follows for each test operation, and in addition, tests were also performed when the pulverized coal injection speed was fixed at 200 kg / t-hot metal. Comparative Example 2: 0 times / minute, Comparative Example 3: 5 times / minute, Comparative Example 4: 10 times / minute, Example 2: 15 times / minute, Example 3: 20 times / minute, Example 4 : 25 times / minute, Example 5: 30 times / minute, Example 6: 35 times / minute, and Example 7: 40 times / minute.

【００５６】上記各試験操業において、ブローパイプへ
の熱風送風圧と、羽口上方７ｍにおけるボッシュ内圧と
の差圧ΔＰを経時的に測定し、得られた差圧ΔＰの平均
値ΔＰav.を、各試験操業について求めた。図７に、微
粉炭吹込み速度及びこれに同調させた酸素富化空気の吹
込み速度のサインカーブによる変化の振動数と、上記差
圧ΔＰの平均値ΔＰav.との関係を示す。同図によれ
ば、微粉炭吹込み速度及び酸素富化空気吹込み速度の振
動数が、１５回／分未満に低下すると、上記差圧の平均
値ΔＰav.が比較的急激に増大し、炉下部通気抵抗が増
大することがわかる。一方、上記振動数が１５回／分以
上においては上記差圧の平均値ΔＰav.は低い水準にあ
り、その振動数の増加につれて当該差圧の平均値ΔＰ
av.はますます低下し、炉下部通気性が改善されること
がわかる。但し、その振動数が３０回／分を超えて大き
くなっても、当該差圧の平均値ΔＰav.の低下程度は飽
和する傾向にある。In each test operation, the pressure difference ΔP between the hot air blowing pressure to the blow pipe and the Bosch internal pressure 7 m above the tuyere was measured with time, and the average value ΔP av. Of the obtained pressure difference ΔP was measured . Was determined for each test run. FIG. 7 shows the relationship between the frequency of the change of the pulverized coal blowing speed and the blowing speed of the oxygen-enriched air synchronized therewith by the sine curve, and the average value ΔP av. Of the differential pressure ΔP. According to the figure, when the frequencies of the pulverized coal injection speed and the oxygen-enriched air injection speed are reduced to less than 15 times / minute, the average value ΔP av. Of the differential pressure increases relatively sharply, It can be seen that the resistance at the lower part of the furnace increases. On the other hand, when the frequency is 15 times / minute or more, the average value ΔP av. Of the differential pressure is at a low level, and as the frequency increases, the average value ΔP a
av. is further reduced, and it can be seen that the lower part of the furnace has improved air permeability. However, even if the frequency exceeds 30 times / min, the degree of decrease in the average value ΔP av of the differential pressure tends to be saturated.

【００５７】上述した通り、微粉炭吹込み速度及び酸素
富化空気の吹込み速度が、それぞれの吹込み速度の平均
値の５０％〜１５０％の間を変化しても、その変化の振
動数が１５回／分未満になると、炉下部通気性が悪化す
るのは、レースウェイ深さ、従って鳥の巣の生成・成長
位置の前後への運動が緩慢になるために、当該各吹込み
速度を変化させても、コークス層内にホールドアップさ
れた多量に灰分を吸収したスラグを振るい落す作用・効
果が急激に低下するためである。一方、上記吹込み速度
の振動数が３０回／分を超えて大きくなっても、炉下部
通気性が飽和するのは、各吹込み速度変化の周期が短く
なることにより生じるレースウェイ深さ、従って鳥の巣
の生成・成長位置の前後方向への運動促進効果が飽和す
るために、コークス層内にホールドアップされたスラグ
を振るい落す作用・効果の増大が停止するためである。As described above, even if the pulverized coal blowing speed and the oxygen-enriched air blowing speed change between 50% and 150% of the average value of the respective blowing speeds, the frequency of the change is not changed. When the air flow rate is less than 15 times / min, the lowering of the furnace lower air permeability is caused by the slowing of the movement of the raceway depth, and thus the movement of the bird's nest in front of and behind the generation / growth position. The effect and effect of shaking off the slag held up in the coke layer and absorbing a large amount of ash are sharply reduced even if the temperature is changed. On the other hand, even if the frequency of the blowing speed is increased beyond 30 times / min, the lower furnace air permeability is saturated because the raceway depth caused by the shorter cycle of each blowing speed change, Therefore, the effect of promoting the movement of the bird's nest in the fore-and-aft direction of the generation / growth position is saturated, and the effect of shaking off the slag held up in the coke layer is stopped from increasing.

【００５８】以上の結果より、本発明の第１の実施形態
による微粉炭の多量吹込みによる高炉の操業方法を、よ
り望ましい条件で行なうことができ、レースウェイ奥に
おける鳥の巣の生成・成長の抑制を一層安定した条件下
で行なうことができ、従来の微粉炭の多量吹込みによる
高炉の操業方法におけるよりも、炉下部通気性が著しく
改善されることがわかる。From the above results, the method of operating a blast furnace by injecting a large amount of pulverized coal according to the first embodiment of the present invention can be performed under more desirable conditions, and the formation and growth of bird nests at the back of the raceway Can be suppressed under more stable conditions, and it can be seen that the air permeability in the lower part of the furnace is remarkably improved as compared with the conventional blast furnace operating method by blowing a large amount of pulverized coal.

【００５９】［試験３］試験１及び試験２と同一の、内
容積４８２８ｍ3 、羽口数４０本を備えた高炉におい
て、表１に示した操業条件をベースとして、本発明の範
囲内に属する微粉炭の多量吹込み操業試験を、次の要領
で行なった（実施例８）。[Test 3] In the same blast furnace as in Tests 1 and 2 having an inner volume of 4828 m 3 and a number of tuyeres of 40, based on the operating conditions shown in Table 1, fine powder falling within the scope of the present invention. A large coal injection operation test was performed in the following manner (Example 8).

【００６０】図２に示した本発明の第２の実施形態で説
明した微粉炭吹込み用ランスの取付け方法及び微粉炭供
給方法により、微粉炭の多量吹込み操業試験を行なっ
た。即ち、高炉の各羽口２に連接するブローパイプ３の
周壁を貫通させて、常用の単管構造の微粉炭吹込み用ラ
ンス４を各羽口２に１本ずつ取り付け、これより微粉炭
吹込み比２００ｋｇ／ｔ−溶銑の一定量の微粉炭を高炉
炉内に吹き込んだ。A pulverized coal blowing operation test was performed by the method of mounting the pulverized coal blowing lance and the method of supplying pulverized coal described in the second embodiment of the present invention shown in FIG. That is, a single-pipe pulverized coal injection lance 4 is attached to each tuyere 2 by penetrating the peripheral wall of the blow pipe 3 connected to each tuyere 2 of the blast furnace. A fixed amount of pulverized coal with a charging ratio of 200 kg / t-hot metal was blown into the blast furnace.

【００６１】一方、酸素吹込み用ノズル１３を、同じく
ブローパイプ３の周壁を貫通させて、各ブローパイプに
１本ずつ取り付けた。酸素吹込み用ノズル１３の先端部
には、図８に縦断面構造を示す超音速ノズル１６を設け
た。On the other hand, one oxygen injection nozzle 13 was attached to each blow pipe by penetrating the peripheral wall of the blow pipe 3 in the same manner. A supersonic nozzle 16 whose longitudinal section is shown in FIG. 8 is provided at the tip of the oxygen blowing nozzle 13.

【００６２】操業試験は、表１に示したベース操業条件
下における従来の微粉炭多量吹込み条件による通常の高
炉操業である比較例５を行なっているときに、ブローパ
イプ３からの熱風６の送風圧と、羽口２の軸線上方７ｍ
におけるボッシュ内圧との差圧ΔＰが、所定の基準値を
超えた時期に、図８に示した超音速ノズル１６から、工
業用純酸素ガスを、圧力１０ｋｇ／ｃｍ2Ｇで噴射し、
炉内に吹込んで行なった。この場合の工業用純酸素の吹
込み流量は、ブローパイプ３からの熱風６の送風に対す
る酸素富化率換算で、３％に相当する流量である。そし
て、当該純酸素ガスの流速は、温度２５℃とすると、４
００ｍ／ｓと算定され、これはマッハ１．２に相当する
ものである。In the operation test, when the comparative example 5, which is a normal blast furnace operation under the conventional pulverized coal mass injection conditions under the base operation conditions shown in Table 1, was performed, the hot air 6 from the blow pipe 3 was blown. Blow pressure and 7 m above the axis of tuyere 2
At the time when the pressure difference ΔP from the internal pressure of Bosch exceeds a predetermined reference value, industrial pure oxygen gas is injected at a pressure of 10 kg / cm 2 G from the supersonic nozzle 16 shown in FIG.
This was performed by blowing into the furnace. In this case, the flow rate of the industrial pure oxygen is a flow rate corresponding to 3% in terms of an oxygen enrichment rate for the hot air 6 blown from the blow pipe 3. When the flow rate of the pure oxygen gas is 25 ° C., 4
It was calculated to be 00 m / s, which corresponds to Mach 1.2.

【００６３】上記の通り、酸素吹込み用ノズル１３から
の純酸素ガスの吹込みは、上記差圧ΔＰが、所定の基準
値を超えた時期にこれを開始したが、当該純酸素吹込み
開始後のその吹込みパターンは、次の通り行なった。即
ち、純酸素吹込み開始と共に、最初の１０分間は、ブロ
ーパイプ３からの送風に対する酸素富化率換算で、３ｖ
ｏｌ％に相当する純酸素流量を吹込み、次の１０分間
は、当該純酸素ガスの吹込みを停止し、次いで次の１０
分間は、再度、ブローパイプ３からの送風に対する酸素
富化率換算で、３ｖｏｌ％に相当する純酸素流量を吹込
み、次いで次の１０分間は、再度当該純酸素ガスの吹込
みを停止するというように、純酸素ガスを１０分間隔で
間欠的に炉内に吹込むというサイクル操作を、５時間繰
り返して行なった後、純酸素ガスの吹込みを停止した。
この停止後２０時間にわたり、酸素吹込み用ノズル１３
からの純酸素ガスの炉内吹込みを停止し、その間、ΔＰ
をモニターした。As described above, the injection of pure oxygen gas from the oxygen injection nozzle 13 was started when the pressure difference ΔP exceeded a predetermined reference value. The subsequent blowing pattern was performed as follows. That is, for the first 10 minutes along with the start of the pure oxygen injection, the oxygen enrichment rate for the air blown from the blow pipe 3 is 3 v
% of pure oxygen gas is blown in, the blowing of the pure oxygen gas is stopped for the next 10 minutes, and then the next 10 minutes.
For another minute, a pure oxygen flow rate equivalent to 3 vol% in terms of an oxygen enrichment rate for blowing air from the blow pipe 3 is blown again, and then, for the next 10 minutes, the blowing of the pure oxygen gas is stopped again. As described above, the cycle operation of intermittently blowing the pure oxygen gas into the furnace at intervals of 10 minutes was repeated for 5 hours, and then the blowing of the pure oxygen gas was stopped.
For 20 hours after the stop, the oxygen injection nozzle 13
Of the pure oxygen gas from the furnace into the furnace is stopped.
Was monitored.

【００６４】図９に、上述した実施例８を行なう前にお
ける従来の微粉炭多量吹込み高炉操業である試験操業
（比較例５）と、実施例８の試験操業中とにおける、熱
風６の送風圧とボッシュ内圧との差圧ΔＰの経時変化の
測定結果を示す。図９によれば、実施例８により、純酸
素ガスの吹込み開始後約１時間経過した頃から、当該差
圧ΔＰの低下傾向が認められ、純酸素ガスの吹込み開始
後約５時間で、当該差圧ΔＰは低位に安定し、そしてそ
の後少なくとも２０時間にわたって当該差圧ΔＰは低レ
ベルが維持された。これは、上記純酸素ジェットの炉内
吹込みにより鳥の巣内のコークスを積極的に燃焼させる
ことにより、レースウェイ奥の通気性が改善され、ま
た、このようにしてその通気性が一旦改善されると、そ
の状態が長時間持続されることを示すものである。FIG. 9 shows a test operation (Comparative Example 5), which is a conventional pulverized coal injection operation with a large amount of pulverized coal before performing Example 8 described above, and a flow of hot air 6 during the test operation of Example 8. The measurement result of the time-dependent change of the differential pressure ΔP between the wind pressure and the Bosch internal pressure is shown. According to FIG. 9, according to Example 8, the tendency of the pressure difference ΔP to decrease was observed at about one hour after the start of the pure oxygen gas injection, and about five hours after the start of the pure oxygen gas injection. , The differential pressure ΔP stabilized at a low level, and the differential pressure ΔP was maintained at a low level for at least 20 hours thereafter. This is because the pure oxygen jet blows into the furnace to actively combust the coke in the bird's nest, thereby improving the ventilation at the back of the raceway, and thus improving the ventilation once. This indicates that the state will be maintained for a long time.

【００６５】以上の結果より、本発明の第２の実施形態
の望ましい微粉炭の多量吹込みによる高炉の操業方法に
より、操業の安定状態を判断しつつ、適切な時期に適切
な時間帯に、ブローパイプに挿入されたノズルから酸素
ジェットを炉内に間欠的に吹き込むことにより、鳥の巣
の生成・成長を抑制することが可能であり、炉下部通気
性の著しい改善効果が得られることがわかる。From the above results, it is possible to determine the stable state of the operation by the desirable method of operating the blast furnace by injecting a large amount of pulverized coal according to the second embodiment of the present invention, By intermittently blowing an oxygen jet into the furnace from the nozzle inserted in the blow pipe, it is possible to suppress the formation and growth of bird nests, and it is possible to obtain a remarkable effect of improving air permeability at the bottom of the furnace. Understand.

【００６６】［試験４］試験１〜試験３と同一の、内容
積４８２８ｍ3 、羽口数４０本を備えた高炉において、
表１に示した操業条件をベースとして、本発明の範囲内
に属する微粉炭の多量吹込み操業試験（実施例９）、及
びブローパイプに装着した酸素吹込み用ノズルからの酸
素の流速が、本発明の範囲外に遅い微粉炭の多量吹込み
操業試験（比較例６、７）を次の要領で行なった。[Test 4] In a blast furnace equipped with the same internal volume of 4828 m 3 and the number of tuyeres as in Tests 1 to 3,
On the basis of the operation conditions shown in Table 1, a large-volume pulverized coal blowing operation test (Example 9) falling within the scope of the present invention and the flow rate of oxygen from the oxygen injection nozzle attached to the blow pipe were as follows: A large pulverized coal blowing operation test (Comparative Examples 6 and 7) outside the scope of the present invention was performed in the following manner.

【００６７】実施例９並びに比較例６及び比較例７の全
てについて、微粉炭吹込み用ランスの取付け方法及び微
粉炭供給方法を、図２に示した本発明の第２の実施形態
で説明した通り、ブローパイプ３の周壁を貫通させて、
常用の単管構造の微粉炭吹込み用ランス４を１本ずつ取
り付け、これより微粉炭吹込み比２００ｋｇ／ｔ−溶銑
の一定量の微粉炭を高炉炉内に吹き込んだ。一方、酸素
吹込み用ノズル１３を、同じくブローパイプ３の周壁を
貫通させて、各ブローパイプに１本ずつ取り付け、これ
より工業用純酸素ガスを炉内に吹き込んだ。ここで、酸
素吹込み用ノズル１３としては、単管構造のものを採用
した。In all of Example 9 and Comparative Examples 6 and 7, the method of mounting the pulverized coal blowing lance and the method of supplying pulverized coal were described in the second embodiment of the present invention shown in FIG. As you can see, through the peripheral wall of the blow pipe 3,
A single pulverized coal injection lance 4 having a conventional single-pipe structure was attached one by one, and a fixed amount of pulverized coal of 200 kg / t-hot metal was blown into the blast furnace from this. On the other hand, an oxygen injection nozzle 13 was also attached to each blow pipe by penetrating the peripheral wall of the blow pipe 3, and industrial pure oxygen gas was blown into the furnace. Here, as the oxygen blowing nozzle 13, a single tube structure was adopted.

【００６８】なお、ブローパイプ３から炉内への熱風６
吹き込み条件は、温度１２００℃、圧力３．７ｋｇ／ｃ
ｍ2Ｇ、羽口２先端における流速２２０ｍ／ｓである。The hot air 6 from the blow pipe 3 into the furnace
The blowing conditions were as follows: temperature 1200 ° C, pressure 3.7 kg / c.
m 2 G, the flow velocity at the tip of the tuyere 2 is 220 m / s.

【００６９】一方、単管構造の酸素吹込み用ノズル１３
から噴射させる工業用純酸素ガスの吹込み条件は、圧力
を４〜６ｋｇ／ｃｍ2Ｇの範囲内において調整し、酸素
吹込み用ノズル１３先端における当該純酸素ガス流速
を、１００ｍ／ｓ（比較例６）、２００ｍ／ｓ（比較例
７）、及び３００ｍ／ｓ（実施例９）の３水準で試験を
行なった。これら場合における当該純酸素ガス吹込み流
量は、送風に対する酸素富化率換算で、３ｖｏｌ％に相
当する。On the other hand, the oxygen injection nozzle 13 having a single pipe structure
The conditions for injecting the industrial pure oxygen gas injected from the nozzle are as follows: the pressure is adjusted within the range of 4 to 6 kg / cm 2 G, and the flow rate of the pure oxygen gas at the tip of the oxygen injection nozzle 13 is 100 m / s (comparison). The test was performed at three levels: Example 6), 200 m / s (Comparative Example 7), and 300 m / s (Example 9). The pure oxygen gas injection flow rate in these cases is equivalent to 3 vol% in terms of oxygen enrichment rate for the air blow.

【００７０】操業試験は、表１に示したベース操業条件
下において、従来の微粉炭多量吹込み操業条件により通
常の高炉操業を行なっている試験操業（比較例５）の所
定時期に、比較例６、比較例７あるいは実施例９を実施
した。当該試験条件への変更前における熱風６の送風圧
とボッシュ内圧との差圧ΔＰbf、及び、当該試験期間に
おける当該差圧ΔＰafを測定し、それらの差ΔＰbf−Δ
Ｐafを求めて、微粉炭多量吹込み操業における実施例の
優位性を評価した。The operation test was carried out at a predetermined time in a test operation (Comparative Example 5) in which a normal blast furnace operation was performed under the conventional pulverized coal mass injection operation conditions under the base operation conditions shown in Table 1. 6, Comparative Example 7 or Example 9 was performed. The pressure difference ΔP bf between the blowing pressure of the hot air 6 and the Bosch internal pressure before the change to the test conditions and the pressure difference ΔP af during the test period were measured, and the difference ΔP bf −Δ
P af was determined to evaluate the superiority of the example in the pulverized coal injection operation.

【００７１】上記試験結果に基づき、図１０に、熱風６
の送風圧とボッシュ内圧との差圧ΔＰの低下に及ぼす、
酸素吹込み用ノズルから炉内に吹き込まれた純酸素ガス
の当該ノズル先端における流速の影響を示す。なお、同
図には、試験３における実施例８で得られた結果もプロ
ットした。同図によれば、ノズルから吹き込まれる純酸
素ガスの流速が、本発明の条件以下に遅い比較例６及び
比較例７においては、熱風６の送風圧とボッシュ内圧と
の差圧ΔＰの低下に対する改善効果が殆ど認められな
い。これに対して、当該純酸素ガスの流速が速くなり、
本発明の条件に該当する実施例９及び実施例８において
は、熱風６の送風圧とボッシュ内圧との差圧ΔＰの低下
が急激に低下して、当該純酸素ガス流速の増大効果が顕
著にみられる。Based on the above test results, FIG.
Effect on the reduction of the pressure difference ΔP between the air blowing pressure and the Bosch internal pressure,
The influence of the flow velocity of the pure oxygen gas blown into the furnace from the oxygen blowing nozzle at the tip of the nozzle is shown. In addition, FIG. 11 also plots the results obtained in Example 8 in Test 3. According to the figure, in Comparative Examples 6 and 7 in which the flow rate of the pure oxygen gas blown from the nozzle is lower than the condition of the present invention, the pressure difference ΔP between the blowing pressure of the hot air 6 and the Bosch internal pressure is reduced. Almost no improvement effect is observed. On the other hand, the flow rate of the pure oxygen gas increases,
In Examples 9 and 8 corresponding to the conditions of the present invention, the decrease in the pressure difference ΔP between the blowing pressure of the hot air 6 and the Bosch internal pressure sharply decreases, and the effect of increasing the pure oxygen gas flow rate is remarkable. Be looked at.

【００７２】以上の結果より、本発明の第２の実施形態
の望ましい微粉炭の多量吹込みによる高炉の操業方法、
特に、ブローパイプから吹き込まれる酸素富化ガスの流
速を速めて、熱風の羽口先端における流速の凡そ１．５
倍以上の高速にすることにより、炉下部通気性が著しく
改善されることがわかる。これは、羽口を通って炉内に
高速で吹き込まれる酸素ガスが、レースウェイ奥まで到
達することによって、レースウェイ奥の温度が上昇する
と同時に、酸化性ガス（Ｏ2、ＣＯ2）が鳥の巣部分に存
在するコークスを効率よく積極的に燃焼させるために、
この領域のコークス層の充填密度低下と温度上昇が同時
に達成され、且つこれに伴ないガス流れがレースウェイ
奥に流れるようになるため、その対流伝熱によっても鳥
の巣の生成・成長が抑制されたものと考えられる。From the above results, the method of operating the blast furnace by injecting a large amount of desirable pulverized coal according to the second embodiment of the present invention,
In particular, the flow rate of the oxygen-enriched gas blown from the blow pipe is increased so that the flow velocity of the hot air at the tuyere tip is about 1.5 times.
It can be seen that by increasing the speed by at least twice, the gas permeability at the lower part of the furnace is remarkably improved. This is because the oxygen gas blown into the furnace at high speed through the tuyere reaches the inside of the raceway, so that the temperature inside the raceway rises and at the same time the oxidizing gas (O 2 , CO 2 ) In order to efficiently and actively burn the coke existing in the nest,
A decrease in the packing density of the coke layer in this area and a rise in temperature are simultaneously achieved, and the accompanying gas flow flows to the back of the raceway, so that the convection heat transfer suppresses the formation and growth of bird's nests. It is thought that it was done.

【００７３】[0073]

【発明の効果】上述したように、この発明によれば、微
粉炭を１８０ｋｇ／ｔ−溶銑以上の多量に吹き込む高炉
の操業において、微粉炭中及びコークス中の灰分、並び
に上方から滴下してくるスラグ及びメタルによって、レ
ースウェイの奥端部に形成される厚い鳥の巣の生成・成
長を抑制することが可能となる。その結果、レースウェ
イ周りの通気性が著しく改善され、炉下部通気性が改善
され、炉内の通気性を良好に維持することができる。こ
の結果、高炉の炉壁部熱負荷の上昇や荷下がり変動、ス
リップ、吹抜け等の炉況悪化を回避することが可能とな
り、安定した微粉炭多量吹込み操業が可能となる。この
発明によればこのような高炉の安定操業を可能とする、
微粉炭の多量吹込みによる高炉操業方法を提供すること
ができ、工業上有用な効果がもたらされる。As described above, according to the present invention, in the operation of a blast furnace in which pulverized coal is blown in a large amount of 180 kg / t-hot metal or more, ash in pulverized coal and coke and drops from above are dropped. With the slag and metal, it is possible to suppress the generation and growth of a thick bird's nest formed at the far end of the raceway. As a result, the air permeability around the raceway is remarkably improved, the air permeability in the lower part of the furnace is improved, and the air permeability in the furnace can be maintained well. As a result, it is possible to avoid a furnace condition deterioration such as an increase in the heat load of the furnace wall of the blast furnace, fluctuations in the load drop, slippage, blow-through, etc., and a stable pulverized coal injection operation becomes possible. According to the present invention, such a blast furnace can be operated stably,
A method for operating a blast furnace by injecting a large amount of pulverized coal can be provided, and an industrially useful effect is provided.

【図面の簡単な説明】[Brief description of the drawings]

【図１】この発明の第１の実施形態における、微粉炭吹
込み用ランスのブローパイプへの取付け状態の望ましい
例を示す縦断面模式図である。FIG. 1 is a schematic longitudinal sectional view showing a desirable example of a state in which a pulverized coal injection lance is attached to a blow pipe in a first embodiment of the present invention.

【図２】この発明の第２の実施形態における、微粉炭吹
込み用ランス並びに酸素富化ガス又は純酸素吹込み用ノ
ズルの、ブローパイプへの取付け状態の望ましい例を示
す縦断面模式図である。FIG. 2 is a schematic longitudinal sectional view showing a desirable example of a state in which a pulverized coal injection lance and an oxygen-enriched gas or pure oxygen injection nozzle are attached to a blow pipe in a second embodiment of the present invention. is there.

【図３】実施例１及び比較例１における微粉炭吹込み比
の時間経過に対する変化パターンを示す図である。FIG. 3 is a diagram showing a change pattern of a pulverized coal injection ratio with time in Example 1 and Comparative Example 1.

【図４】実施例１及び比較例１の各試験操業期間中の代
表的時期における熱風送風圧とボッシュ内圧との差圧Δ
Ｐの経時変化を示すグラフである。FIG. 4 is a differential pressure Δ between hot air blowing pressure and Bosch internal pressure at a representative time during each test operation period of Example 1 and Comparative Example 1.
It is a graph which shows a time-dependent change of P.

【図５】操業中に炉芯ゾンデをレースウェイ奥に挿入す
る状況を説明する縦断面模式図である。FIG. 5 is a schematic vertical cross-sectional view illustrating a situation in which a furnace core sonde is inserted into the back of a raceway during operation.

【図６】羽口先端からの前方距離に対する、炉芯ゾンデ
挿入推力の変化の例を示すグラフである。FIG. 6 is a graph showing an example of a change in a thrust for inserting a core lead into a forward distance from a tuyere tip.

【図７】微粉炭吹込み速度及びこれに同調させた酸素富
化空気の吹込み速度のサインカーブ変化の振動数が、熱
風送風圧とボッシュ圧との差圧の低下に及ぼす影響を示
すグラフである。FIG. 7 is a graph showing the effect of the frequency of the sine curve change of the pulverized coal blowing speed and the blowing speed of the oxygen-enriched air synchronized therewith on the decrease in the differential pressure between the hot air blowing pressure and the Bosch pressure. It is.

【図８】この発明の第２の実施形態における、酸素吹込
み用ノズルの先端部に設けられた超音速ノズルの実施例
の縦断面構造図である。FIG. 8 is a longitudinal sectional structural view of an example of a supersonic nozzle provided at the tip of an oxygen blowing nozzle according to a second embodiment of the present invention.

【図９】この発明の第２の実施形態の望ましい実施例に
おける、熱風送風圧とボッシュ内圧との差圧ΔＰの経時
変化を示すグラフである。FIG. 9 is a graph showing a change with time in a pressure difference ΔP between a hot air blowing pressure and a Bosch internal pressure in a desirable example of the second embodiment of the present invention.

【図１０】熱風送風圧とボッシュ内圧との差圧（ΔＰ）
低下に及ぼす純酸素ガス流速の影響を示すグラフであ
る。FIG. 10: Differential pressure (ΔP) between hot air blowing pressure and Bosch internal pressure
4 is a graph showing the effect of a pure oxygen gas flow rate on a decrease.

【図１１】高炉の炉内に微粉炭を吹込む状況を説明する
縦断面模式図である。FIG. 11 is a schematic vertical cross-sectional view illustrating a situation in which pulverized coal is injected into a furnace of a blast furnace.

【図１２】レースウェイ奥に形成される鳥の巣を説明す
る縦断面模式図である。FIG. 12 is a schematic vertical sectional view illustrating a bird's nest formed in the back of a raceway.

【符号の説明】[Explanation of symbols]

１ 高炉 ２ 羽口 ３ ブローパイプ ４ 微粉炭吹込み用ランス ５ 微粉炭 ６ 熱風 ７ レースウェイ ８ コークス ９ メタル １０ スラグ １１ 鳥の巣 １２ 炉壁 １３ 酸素富化ガス又は純酸素吹込み用ノズル １４ 酸素富化ガス又は純酸素のジェット １４ａ 酸素富化ガス又は純酸素 １５ 炉芯ゾンデ １６ 超音速ノズル １７ 装入原料層 １８ 融着帯 １９ 炉芯 ２０ スラグ ２１ 溶銑 Reference Signs List 1 blast furnace 2 tuyere 3 blow pipe 4 pulverized coal injection lance 5 pulverized coal 6 hot air 7 raceway 8 coke 9 metal 10 slag 11 bird's nest 12 furnace wall 13 nozzle for injecting oxygen-enriched gas or pure oxygen 14 oxygen Jet of enriched gas or pure oxygen 14a Oxygen-enriched gas or pure oxygen 15 Furnace core sonde 16 Supersonic nozzle 17 Charged material layer 18 Cohesive zone 19 Furnace core 20 Slag 21 Hot metal

───────────────────────────────────────────────────── フロントページの続き (72)発明者 松浦 正博 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 村井 亮太 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 後藤 和也 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 村尾 明紀 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 酒井 敦 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 松原 真二 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 森 候寿 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 Ｆターム(参考） 4K012 BD02 BD04 BE01 BE06 BE07 4K015 AC01 AC02 AC05 AC10 AD01 AD02 AD10  ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahiro Matsuura 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Ryota Murai 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan (72) Inventor Kazuya Goto 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan 1-2.Inventor Akiki Murao 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Inside the Kokan Co., Ltd. (72) Inventor Atsushi Sakai 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Shinji Matsubara 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan In-house Co., Ltd. (72) Inventor Koji Mori 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Japan Tube Co., Ltd. F-term (reference) 4K012 BD02 BD04 BE01 BE06 BE 07 4K015 AC01 AC02 AC05 AC10 AD01 AD02 AD10

Claims (8)

【特許請求の範囲】[Claims] 【請求項１】 高炉の羽口から当該高炉の炉内に熱風を
吹き込むために当該羽口の手前に連接して設けられたブ
ローパイプの周壁を貫通して挿入された微粉炭吹込み用
ランスを用いて、当該高炉に１８０ｋｇ／ｔ−溶銑以上
の微粉炭を吹き込む高炉の操業方法において、前記微粉
炭吹込み用ランスからの当該微粉炭の吹込み速度を、当
該微粉炭の平均吹込み速度の５０〜１５０％の範囲内に
おいて変化させ、且つその変化をさせる頻度を１分間に
１５回以上とすることを特徴とする、微粉炭の多量吹込
みによる高炉の操業方法。1. A pulverized coal injection lance inserted through a peripheral wall of a blow pipe connected in front of the tuyere to blow hot air from the tuyere of the blast furnace into the furnace of the blast furnace. In the method for operating a blast furnace in which pulverized coal of 180 kg / t-hot metal or more is blown into the blast furnace by using the blast furnace, the blowing speed of the pulverized coal from the lance for blowing pulverized coal is determined by the average blowing speed of the pulverized coal. A method for operating a blast furnace by injecting a large amount of pulverized coal, wherein the blast furnace is changed within a range of 50 to 150% of the above, and the frequency of the change is 15 times or more per minute. 【請求項２】 前記微粉炭の吹込み速度を変化させる頻
度を、１分間に１５〜３０回の範囲内とすることを特徴
とする、請求項１記載の微粉炭の多量吹込みによる高炉
の操業方法。2. The blast furnace according to claim 1, wherein the frequency of changing the blowing speed of the pulverized coal is within a range of 15 to 30 times per minute. Operation method. 【請求項３】 前記微粉炭吹込み用ランスとして同心２
重管構造のランスを用い、その内管から前記微粉炭を吹
込み、そしてその内管と外管との間隙から酸素富化ガス
又は純酸素を吹き込むことを特徴とする、請求項１記載
の微粉炭の多量吹込みによる高炉の操業方法。3. A concentric 2 as said pulverized coal injection lance.
The lance having a double pipe structure is used, and the pulverized coal is blown from the inner pipe, and oxygen-enriched gas or pure oxygen is blown from the gap between the inner pipe and the outer pipe. How to operate a blast furnace by injecting a large amount of pulverized coal. 【請求項４】 前記微粉炭吹込み用ランスとして同心２
重管構造のランスを用い、その内管から前記微粉炭を吹
込み、そしてその内管と外管との間隙から酸素富化ガス
又は純酸素を吹き込むことを特徴とする、請求項２記載
の微粉炭の多量吹込みによる高炉の操業方法。4. A concentric 2 as said pulverized coal injection lance.
3. The lance according to claim 2, wherein the pulverized coal is blown from the inner pipe using a lance having a double pipe structure, and oxygen-enriched gas or pure oxygen is blown from the gap between the inner pipe and the outer pipe. How to operate a blast furnace by injecting a large amount of pulverized coal. 【請求項５】 前記２重管構造ランスの内管から吹き込
む前記微粉炭吹込み速度の変化を周期的変化パターンに
設定し、且つ、当該微粉炭吹込み速度の周期的変化パタ
ーンに同調させて、前記内管と外管との間隙から吹き込
む前記酸素富化ガス又は純酸素の吹込み速度を当該酸素
富化ガス又は純酸素の平均吹込み速度の５０〜１５０％
の範囲内において変化させることを特徴とする、請求項
３又は請求項４記載の微粉炭の多量吹込みによる高炉の
操業方法。5. A change in the pulverized coal blowing speed blown from the inner pipe of the double pipe structure lance is set to a periodic change pattern, and is synchronized with the periodic change pattern of the pulverized coal blow speed. The blowing speed of the oxygen-enriched gas or pure oxygen blown from the gap between the inner tube and the outer tube is 50 to 150% of the average blowing speed of the oxygen-enriched gas or pure oxygen.
The method for operating a blast furnace by injecting a large amount of pulverized coal according to claim 3 or 4, wherein the blast furnace is varied within the range of: 【請求項６】 高炉の羽口から当該高炉の炉内に熱風を
吹き込むために当該羽口の手前に連接して設けられたブ
ローパイプの周壁を貫通して挿入された微粉炭吹込み用
ランスを用いて、当該高炉に１８０ｋｇ／ｔ−溶銑以上
の微粉炭を吹き込む高炉の操業方法において、当該微粉
炭吹込み用ランスの他に、前記ブローパイプの周壁を貫
通して酸素富化ガス又は純酸素の吹込み用ノズルを挿入
し、当該酸素富化ガス又は純酸素の吹込み用スノズルか
ら当該酸素富化ガス又は純酸素のジェットを、前記ブロ
ーパイプから前記高炉内へ吹き込まれる熱風の前記羽口
先端における流速の１．５倍以上の速度で噴射させて炉
内に吹き込むことを特徴とする、微粉炭の多量吹込みに
よる高炉の操業方法。6. A pulverized coal injection lance inserted through a peripheral wall of a blow pipe connected in front of the tuyere to blow hot air from the tuyere of the blast furnace into the furnace of the blast furnace. In the blast furnace operating method of injecting pulverized coal of 180 kg / t-hot metal or more into the blast furnace using the blast furnace, in addition to the pulverized coal injection lance, the oxygen-enriched gas or pure gas is passed through the peripheral wall of the blow pipe. An oxygen blowing nozzle is inserted, and the oxygen-enriched gas or pure oxygen jet is blown from the oxygen-enriched gas or pure oxygen blowing nozzle, and the hot air wings blown into the blast furnace from the blow pipe. A method for operating a blast furnace by injecting a large amount of pulverized coal, wherein the blast furnace is injected at a rate of 1.5 times or more the flow velocity at the mouth end and blown into the furnace. 【請求項７】 前記酸素富化ガス又は純酸素のジェット
の吹込みは、高炉の操業安定状態に応じて、当該ジェッ
トを前記高炉内へ吹き込む時期と吹き込まない時期とを
設けることを特徴とする、請求項６記載の微粉炭の多量
吹込みによる高炉の操業方法。7. The jetting of the jet of the oxygen-enriched gas or pure oxygen is characterized by providing a timing at which the jet is blown into the blast furnace and a timing at which the jet is not blown, according to a stable operation state of the blast furnace. The method for operating a blast furnace according to claim 6, wherein a large amount of pulverized coal is injected. 【請求項８】 前記酸素富化ガス又は純酸素のジェット
を前記高炉の炉内へ吹き込む時期に、当該酸素富化ガス
又は純酸素のジェトを当該高炉の炉内への吹き込むに当
たっては、時間経過に対して間欠的にその酸素富化ガス
又は純酸素のジェトを吹き込むことを特徴とする、請求
項７記載の微粉炭の多量吹込みによる高炉の操業方法。8. When the jet of the oxygen-enriched gas or pure oxygen is blown into the furnace of the blast furnace, the jet of the oxygen-enriched gas or pure oxygen is blown into the furnace of the blast furnace. 8. A method for operating a blast furnace by injecting a large amount of pulverized coal according to claim 7, wherein a jet of the oxygen-enriched gas or pure oxygen is intermittently injected into the blast furnace.
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US7914279B2 (en) 2003-01-21 2011-03-29 American Air Liquide, Inc. Method and apparatus for injecting a gas into a two-phase stream
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US7914279B2 (en) 2003-01-21 2011-03-29 American Air Liquide, Inc. Method and apparatus for injecting a gas into a two-phase stream
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US8173064B2 (en) 2005-11-09 2012-05-08 Thyssenkrupp At.Pro Tec Gmbh Method for operating a shaft furnace, and shaft furnance operable by that method
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CN113106177B (en) * 2021-04-09 2022-06-17 南京工程学院 Anti-blocking and blockage-removing control device and method based on differential type large-scale blast furnace injection system

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