JP2008255402A - Blast furnace operation method - Google Patents

Blast furnace operation method Download PDF

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JP2008255402A
JP2008255402A JP2007097683A JP2007097683A JP2008255402A JP 2008255402 A JP2008255402 A JP 2008255402A JP 2007097683 A JP2007097683 A JP 2007097683A JP 2007097683 A JP2007097683 A JP 2007097683A JP 2008255402 A JP2008255402 A JP 2008255402A
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blast furnace
hot metal
furnace
temperature
brewing
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JP4926790B2 (en
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Daikan Yamamoto
大寛 山本
Yohei Otani
洋平 大谷
Kazuhiro Nishihara
一浩 西原
Masahito Sugiura
雅人 杉浦
Shinroku Matsuzaki
眞六 松崎
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Nippon Steel Corp
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Nippon Steel Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a blast furnace operation method capable of comprehending an operating state in a blast furnace and the fluctuation thereof in an early stage, always keeping, in particular, a deadman part and a hearth part of the blast furnace in an active state, or detecting an inactive state in an early stage to be recovered to the active state. <P>SOLUTION: In the operation of a blast furnace, when manufacturing a pig iron by using blast furnace 10 having first and second tap holes 15, 16 on a side surface of a furnace bottom part, firstly the first tap hole 15 is opened to perform the first iron tapping, and thereafter, the second tap hole 16 is opened to perform the second iron tapping. The pig iron temperature T1b at the terminating period of the first iron tapping and the pig iron temperature T2t at the beginning period of the second tapping are respectively measured, and the operational conditions of the blast furnace are controlled so as to satisfy T2t-T1b>-15°C. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、高炉の操業方法に係り、更に詳細には高炉内の操業状態およびその変動を早期に把握し、高炉の特に炉芯部および炉床部を常に活性状態に保ち、あるいは不活性状態を早期に検知して活性状態に改善する高炉の操業方法に関する。
なお、本発明において、「活性状態」とは、高炉の炉芯および炉床湯溜部において良好な還元反応が十分に進み、熱裕度の保てる操業状態、およびその結果出銑量が高位安定している状態をいい、「不活性状態」とは、高炉の炉芯および炉床湯溜部において還元反応が十分に進まず、熱裕度のない操業状態、およびその結果出銑量が高位安定ではない状態をいう。
The present invention relates to a method of operating a blast furnace, and more particularly, grasps the operating state in the blast furnace and its fluctuations at an early stage, and particularly keeps the core and the hearth of the blast furnace in an active state or in an inactive state. It is related with the operation method of the blast furnace which detects swiftness early and improves to an active state.
In the present invention, the “active state” means that an excellent reduction reaction sufficiently proceeds in the core and hearth hot water reservoir of the blast furnace, and the operation state in which heat tolerance can be maintained, and as a result, the output amount is highly stable. "Inactive state" means that the reduction reaction does not proceed sufficiently in the blast furnace core and the hearth hot water reservoir, the operation state has no heat tolerance, and as a result, the output amount is high. A state that is not stable.

高炉による溶銑の製造においては、鉄鉱石、焼結鉱、ペレット等の鉄原料および燃料であるコークスを、炉頂から装入し、鉄原料とコークスとが交互に堆積した層状構造を保ちながら炉内を下降させる。炉下部の羽口からは、熱風および必要に応じて微粉炭等の補完還元材を吹き込んでコークスを燃焼させ、CO、H等を含む還元性ガスを生成させる。高温の還元性ガスは、上昇気流となって炉内を上昇し、炉内を下降する鉄原料と接触して酸化鉄を還元する(間接還元)。還元され融解した鉄原料は、炉芯部のコークス層内を滴下しながらコークスの炭素と接触してさらに還元され(直接還元)、溶銑となって炉床の湯溜部に溜まる。湯溜部に溜まった溶銑は、炉底部側面に設けられた出銑口から出銑される。 In hot metal production using a blast furnace, iron raw materials such as iron ore, sintered ore, and pellets and coke, which is fuel, are charged from the top of the furnace, maintaining a layered structure in which iron raw materials and coke are alternately deposited. Lower the inside. From the tuyeres at the lower part of the furnace, hot air and, if necessary, a supplementary reducing material such as pulverized coal are blown to burn the coke to produce reducing gas containing CO, H 2 and the like. The high-temperature reducing gas rises in the furnace as an ascending current, and contacts with the iron raw material descending in the furnace to reduce iron oxide (indirect reduction). The reduced and melted iron raw material is further reduced (direct reduction) in contact with the carbon of the coke while dropping in the coke layer of the furnace core, and becomes hot metal and accumulates in the hot water reservoir of the hearth. The hot metal accumulated in the hot water reservoir is discharged from a tap outlet provided on the side surface of the furnace bottom.

高炉の操業状態が活性状態に維持されている場合には、原料の溶解が十分に進み、還元不良物が炉芯部や炉床部に溜まって不透過層を形成することがないため、炉内の通気性および通液性が確保されている。したがって、溶銑は炉芯部および炉床部で滞留して冷却ないしは不透過層へ抜熱されることなく(以下、総称して単に「冷却」ということもある)円滑に流動して出銑口より出銑されるため、出銑口より出銑される溶銑の温度はほぼ一定に保たれる。
一方、高炉の操業状態が不活性状態に転じると、還元不良物が炉芯部や炉床部に溜まって不透過層が形成されるため、炉芯部および炉床部において溶銑の円滑な流れが阻害される。その結果、滞留した溶銑の冷却に伴い、出銑口より出銑される溶銑の温度が低下する。
When the operating state of the blast furnace is maintained in an active state, the melting of the raw material proceeds sufficiently, and defective reduction materials do not accumulate in the furnace core and hearth and form an impermeable layer. Internal air permeability and liquid permeability are ensured. Therefore, the hot metal stays in the furnace core and the hearth, and flows smoothly from the outlet, without being cooled or extracted to the impervious layer (hereinafter sometimes referred to simply as “cooling”). Since it is output, the temperature of the hot metal discharged from the outlet is kept almost constant.
On the other hand, when the operating state of the blast furnace is changed to an inactive state, defective reduction materials accumulate in the furnace core and the hearth, and an impermeable layer is formed. Therefore, a smooth flow of hot metal in the furnace core and the hearth Is inhibited. As a result, with the cooling of the hot metal that has accumulated, the temperature of the hot metal discharged from the outlet is lowered.

不活性状態の発生が、炉口部または炉腹部での還元不良に起因する場合には、炉頂より装入する原料の品質の改善、または羽口から吹き込む熱風の送風温度の増大もしくは微粉炭の吹込み量の増大等による高炉への投入熱量の増大等の措置を早期に講じることにより、数時間程度で活性状態に改善することができる。しかしながら、炉芯部から炉床部にかけて還元不良が発生した場合、生成する不透過層の融解のために炉芯部および炉床部にのみ直接熱量を投入することは高炉の構造上困難であるため、炉内全体に対する投入熱量を増大させる必要があり、より大きなエネルギーを必要とする。
したがって、高炉の操業状態をできるだけ活性状態に保ち、高いエネルギー効率での操業を維持するためには、炉床湯溜部の溶銑温度の低下等の操業状態の不活性化の兆候を早期に感知して、炉頂から装入する原料の品質の改善、および高炉への投入熱量の増大等の適切な措置をできるだけ早期に講じる必要がある。
If the occurrence of the inactive state is caused by poor reduction at the furnace mouth or belly, improve the quality of the raw material charged from the top of the furnace, increase the temperature of hot air blown from the tuyere, or pulverized coal By taking measures such as increasing the amount of heat input to the blast furnace due to an increase in the amount of blown gas, the active state can be improved in about several hours. However, if a reduction failure occurs from the furnace core to the hearth, it is difficult due to the structure of the blast furnace to directly input heat only to the furnace core and the hearth for melting the impervious layer to be generated. For this reason, it is necessary to increase the amount of heat input to the entire furnace, and a larger amount of energy is required.
Therefore, in order to keep the operating state of the blast furnace as active as possible and maintain operation with high energy efficiency, early detection of signs of inactivation of the operating state such as a decrease in hot metal temperature in the hearth hot water reservoir Thus, it is necessary to take appropriate measures as early as possible, such as improving the quality of raw materials charged from the top of the furnace and increasing the amount of heat input to the blast furnace.

一般には、高炉内の炉芯部および炉床湯溜部の不活性状態を判定する方法として、炉底部のレンガの内部に埋め込んだ温度計の測定データが、低い値で安定するか下降に転じる変化を起こした時点を検出する方法が知られている。しかし、この方法では、炉底部のレンガ表面からレンガの内部に埋め込まれた温度計までの熱伝達に数日を要するため、不活性状態の検知までに数日のタイムラグが発生する。そのため、操業状態を改善するための対策が遅れがちとなり、数日〜1ヶ月程度の長期にわたり出銑量の低下に見舞われるとともに、炉内に投入する熱量を増大させる等の改善策を継続して実施する必要が生じる。 In general, as a method of judging the inactive state of the furnace core and hearth pool in the blast furnace, the measurement data of the thermometer embedded in the brick at the bottom of the furnace is stabilized at a low value or turned down A method for detecting a time point at which a change has occurred is known. However, in this method, since several days are required for heat transfer from the brick surface at the bottom of the furnace to the thermometer embedded in the brick, a time lag of several days occurs until the inactive state is detected. As a result, measures to improve the operating condition tend to be delayed, and the amount of heat input to the furnace is increased while the output amount decreases for a long period of several days to one month. Need to be implemented.

上記課題を解決するために、例えば、特許文献1では、高炉の出銑口から排出された溶銑流の温度を金属管で被覆された光ファイバーを利用して測定し、こうして得られた温度情報に基づき高炉炉芯部における活性状態を検知する高炉の操業方法が提案されている。
より具体的には、出銑初期の溶銑温度から当該出銑期間中の最低溶銑温度を差し引いた値をΔTと定義し、炉芯の活性状態の判定基準および活性状態への復旧のために講じる修正アクションの内容については、例えば、ΔTの値およびそのΔTが何回の出銑にわたり継続するか等に応じて予め定めておく。
In order to solve the above problem, for example, in Patent Document 1, the temperature of the hot metal flow discharged from the outlet of the blast furnace is measured using an optical fiber covered with a metal tube, and the temperature information thus obtained is measured. Based on this, a blast furnace operating method for detecting an active state in a blast furnace core has been proposed.
More specifically, a value obtained by subtracting the minimum hot metal temperature during the ironing period from the hot metal temperature in the initial stage of ironing is defined as ΔT, which is taken for the determination criteria for the active state of the furnace core and the restoration to the active state. The content of the corrective action is determined in advance according to, for example, the value of ΔT and how many times the ΔT continues.

特開平11−222611号公報(第6−7頁、図3)JP-A-11-222611 (page 6-7, FIG. 3)

しかしながら、特許文献1に記載の高炉の操業方法では、出銑期間中の溶銑温度の変動のパターンによっては、実際には活性状態であるにもかかわらず不活性状態と誤判定してしまい、その結果過剰な修正措置を講じた結果、高炉の生産効率や還元反応の効率を却って低下させてしまう、あるいは、実際には炉芯部および炉床湯溜部に生成した不透過層を看過して活性状態であると誤判定してしまい、不活性状態からの改善のために必要な措置を講じるタイミングを逸してしまうという問題が発生する場合がある。 However, in the operation method of the blast furnace described in Patent Document 1, depending on the pattern of fluctuation of the hot metal temperature during the tapping period, it is erroneously determined as an inactive state even though it is actually in an active state. As a result of taking excessive corrective measures, the production efficiency of the blast furnace and the efficiency of the reduction reaction may be reduced. There is a case in which it is erroneously determined that the state is the active state, and the timing for taking necessary measures for improvement from the inactive state may be lost.

本発明はかかる事情に鑑みてなされたもので、高炉内の操業状態およびその変動を早期に把握し、高炉の特に炉芯部および炉床部を常に活性状態に保ち、あるいは不活性状態を早期に検知して活性状態に改善する高炉の操業方法を提供することを目的とする。 The present invention has been made in view of such circumstances, and grasps the operating state and its fluctuation in the blast furnace at an early stage, and keeps the core part and the hearth part of the blast furnace in an active state at all times, or an inactive state at an early stage. It is an object of the present invention to provide a method for operating a blast furnace that is detected and improved to an active state.

前記目的に沿う本発明に係る高炉の操業方法は、炉底部側面に第1および第2の出銑口を有する高炉を用いて溶銑を製造するに際し、まず前記第1の出銑口を開口して第1の出銑を行い、その後、前記第2の出銑口を開口して第2の出銑を行う高炉の操業において、前記第1の出銑の末期の溶銑温度T1bと、前記第2の出銑の初期の溶銑溶銑温度T2tとをそれぞれ測定し、T2t−T1b>−15℃となるように前記高炉の操業条件を制御する。
なお、本発明において「第1の出銑」および「第2の出銑」とは、一連の高炉の操業工程におけるある時点を基準時とし、その基準時後の1番目および2番目の出銑をそれぞれ意味し、高炉の操業開始後の第1回および第2回の出銑を意味するわけではない。
「その後、前記第2の出銑口を開口して第2の出銑を行う」とは、第1の出銑口を閉塞して前記第1の出銑を終了した後に第2の出銑口を開口して第2の出銑を行う場合と、第2の出銑口を開口して第2の出銑を開始した後に第1の出銑口を閉塞して第1の出銑を終了する場合のいずれをも意味する。なお、後者の場合、第2の出銑開始から第1の出銑終了までの時間は、0を超え10分以下である。
「第1の出銑の末期の溶銑温度T1b」とは、第1の出銑終了前の20分間における溶銑温度の平均値をいい、「第2の出銑の初期の溶銑温度T2t」とは、第2の出銑開始から20分間における溶銑温度の平均値をいう。
さらに、「溶銑温度」とは、出銑樋や大気への放熱の影響を受けない高炉から流出直後の溶銑の温度をいい、「溶銑温度の平均値」とは、一定間隔ごとに測定した溶銑温度の測定値の総和を、測定値の個数で除した値をいう。
The method of operating a blast furnace according to the present invention in accordance with the above object is to open the first tap hole first when producing hot metal using a blast furnace having first and second tap holes on the side surface of the furnace bottom. In the operation of the blast furnace in which the first brewing is performed and then the second brewing port is opened to perform the second brewing, the hot metal temperature T1b at the end of the first brewing is The initial hot metal hot metal temperature T2t of the second hot metal is measured, and the operating conditions of the blast furnace are controlled so that T2t−T1b> −15 ° C.
In the present invention, “first tapping” and “second tapping” refer to a certain time point in a series of blast furnace operation processes as the reference time, and the first and second outputs after the reference time. It does not mean the first and second tapping after the start of blast furnace operation.
“After that, the second tapper is opened and the second tapper is performed” means that the second tapper is closed after the first tapper is closed and the first tapper is finished. When opening the mouth and performing the second tapping, after opening the second tapping outlet and starting the second tapping, the first tapping outlet is closed and the first tapping is performed. It means any case of termination. In the latter case, the time from the start of the second tapping to the end of the first tapping is greater than 0 and equal to or less than 10 minutes.
“The hot metal temperature T1b at the end of the first hot metal” means an average value of the hot metal temperature for 20 minutes before the end of the first hot metal, and “the initial hot metal temperature T2t of the second hot metal” The average value of the hot metal temperature for 20 minutes from the start of the second brewing.
Furthermore, the “hot metal temperature” refers to the temperature of the hot metal immediately after it flows out of the blast furnace, which is not affected by the heat output or heat release to the atmosphere, and the “average value of the hot metal temperature” refers to the hot metal temperature measured at regular intervals. A value obtained by dividing the sum of measured values of temperature by the number of measured values.

高炉内が活性状態にある場合には、炉床部に不透過層が生成しないので、湯溜部に貯留された溶銑は滞留することなく円滑に流動し、第1の出銑の終了時には、炉床湯溜部の溶銑はほぼ全て排出される。したがって、第2の出銑の開始時には、炉内で生成したばかりの溶銑が冷却を受けることなく排出されるので、T2tの値は、T1bの値を大きく下回ることはない。
一方、高炉内が不活性状態にある場合には、炉芯部や炉床湯溜部に溶銑の流動を阻害する不透過層が生成し、第1の溶銑の終了時に第2の出銑口付近に溶銑の一部が滞留する。したがって、第2の出銑の開始時には、炉床湯溜部に滞留し、炉壁の冷却装置による冷却や不透過層等へ抜熱された低温の溶銑が排出されるので、T2tとT1bとの差は−15℃以下となる。
このように、T2tとT1bとの温度差を比較することにより、高炉内の操業状態を迅速に判定することができる。
When the inside of the blast furnace is in an active state, no impervious layer is generated in the hearth, so the hot metal stored in the hot water reservoir flows smoothly without stagnation, and at the end of the first brewing, Almost all of the hot metal in the hearth pool is discharged. Therefore, since the hot metal just generated in the furnace is discharged without being cooled at the start of the second tapping, the value of T2t does not greatly fall below the value of T1b.
On the other hand, when the inside of the blast furnace is in an inactive state, an impervious layer that inhibits the flow of hot metal is generated in the furnace core and the hearth hot water reservoir, and the second outlet is formed at the end of the first hot metal. Part of the hot metal stays in the vicinity. Therefore, at the start of the second tapping, the low temperature hot metal staying in the hearth hot water reservoir and discharged to the cooling or impervious layer of the furnace wall is discharged, so that T2t and T1b The difference is −15 ° C. or less.
Thus, by comparing the temperature difference between T2t and T1b, the operating state in the blast furnace can be quickly determined.

本発明に係る高炉の操業方法において、T2t−T1b≦−15℃である場合、前記高炉内に装入する原料中のコークス比を増大させてもよい。
なお、「コークス比」とは、溶銑(pig iron)1トンを製造するのに必要なコークス量(kg/ton−pig)をいう。
In the blast furnace operating method according to the present invention, when T2t−T1b ≦ −15 ° C., the coke ratio in the raw material charged into the blast furnace may be increased.
“Coke ratio” refers to the amount of coke (kg / ton-pig) required to produce 1 ton of hot metal (pig iron).

本発明に係る高炉の操業方法において、T2t−T1b≦−15℃である場合、前記高炉内の微粉炭の吹込み量を増大させてもよい。
なお、「微粉炭の吹込み量」とは、溶銑1トンを製造するのに必要な微粉炭の吹込み量(kg/ton−pig)をいう。
In the blast furnace operating method according to the present invention, when T2t−T1b ≦ −15 ° C., the amount of pulverized coal in the blast furnace may be increased.
The “injection amount of pulverized coal” refers to the injection amount (kg / ton-pig) of pulverized coal necessary for producing 1 ton of hot metal.

本発明に係る高炉の操業方法において、T2t−T1b≦−15℃である場合、前記高炉内の送風温度を増大させてもよい。 In the blast furnace operating method according to the present invention, when T2t−T1b ≦ −15 ° C., the blast temperature in the blast furnace may be increased.

請求項1〜4記載の高炉の操業方法においては、第2の出銑の初期の溶銑温度T2tと第1の出銑の末期の溶銑温度T1bとの関係に基づいて、高炉の操業状態が活性状態および不活性状態のいずれであるかを判定する。そのため、高炉内の操業状態の変動を早期にかつ確実に把握することができるので、不活性状態への移行を未然に防ぐための、あるいは、不活性状態を活性状態に早期に改善するための措置を迅速に講じることができ、高炉の活性状態を長期間にわたり維持することができる。
また、T2tとT1bの差に基づいて高炉の操業状態を判定しているため、出銑の途中での一時的な操業条件の変動に伴う溶銑温度の変化を不活性状態への移行と誤判定するおそれが低く、過剰な措置を講じることによって却って操業状態を悪化させてしまうリスクを低減することができる。
In the blast furnace operating method according to claims 1 to 4, the operating condition of the blast furnace is activated based on the relationship between the initial hot metal temperature T2t of the second hot metal and the final hot metal temperature T1b of the first hot metal. It is determined whether the state is inactive or inactive. Therefore, because it is possible to grasp the fluctuation of the operating state in the blast furnace early and reliably, in order to prevent the transition to the inactive state, or to improve the inactive state to the active state early Measures can be taken quickly and the active state of the blast furnace can be maintained for a long time.
In addition, since the operating state of the blast furnace is determined based on the difference between T2t and T1b, a change in hot metal temperature due to a temporary change in operating conditions during the tapping process is erroneously determined as a transition to an inactive state. Therefore, it is possible to reduce the risk of deteriorating the operation state by taking excessive measures.

特に、請求項2記載の高炉の操業方法においては、T2t−T1b≦−15℃となる場合、高炉内に装入する原料中のコークス比を増大させることにより、炉内の熱量を増大させるので、高炉内の炉芯部および炉床湯溜部に生成した不透過層を融解させ、高炉の操業状態を活性状態に改善することができる。 In particular, in the method of operating a blast furnace according to claim 2, when T2t−T1b ≦ −15 ° C., the amount of heat in the furnace is increased by increasing the coke ratio in the raw material charged into the blast furnace. The impervious layer generated in the core and the hearth hot water reservoir in the blast furnace can be melted to improve the operating state of the blast furnace to the active state.

請求項3記載の高炉の操業方法においては、T2t−T1b≦−15℃となる場合、高炉内に装入する原料中の微粉炭の吹込み量を増大させることにより、炉内の熱量を増大させるので、高炉内の炉芯部および炉床湯溜部に生成した不透過層を融解させ、高炉の操業状態を活性状態に改善することができる。 In the operation method of the blast furnace according to claim 3, when T2t-T1b ≦ −15 ° C., the amount of heat in the furnace is increased by increasing the amount of pulverized coal in the raw material charged into the blast furnace. Therefore, the impervious layer produced | generated in the core part and hearth hot water storage part in a blast furnace can be fuse | melted, and the operation state of a blast furnace can be improved to an active state.

請求項4記載の高炉の操業方法においては、T2t−T1b≦−15℃である場合、前記高炉内の送風温度を増大させることにより、炉内の熱量を増大させるので、高炉内の炉芯部および炉床湯溜部に生成した不透過層を融解させ、高炉の操業状態を活性状態に改善することができる。 In the method of operating a blast furnace according to claim 4, when T2t-T1b ≦ −15 ° C., the amount of heat in the furnace is increased by increasing the blowing temperature in the blast furnace. And the impervious layer produced | generated in the hearth hot water storage part can be melt | dissolved, and the operation state of a blast furnace can be improved to an active state.

続いて、添付した図面を参照しつつ、本発明を具体化した実施の形態につき説明し、本発明の理解に供する。
ここで、図1は本発明の本発明の一実施の形態に係る高炉の操業方法に用いられる高炉の概略図、図2(A)は活性状態にある高炉の第1の出銑における出銑後経過時間と溶銑の生成量および出銑量との関係を示すグラフ、図2(B)は同高炉における出銑後経過時間と貯留溶銑量との関係を示すグラフ、図3は活性状態にある高炉の第1の出銑における出銑後経過時間と溶銑温度との関係を示すグラフ、図4(A)は活性状態にある高炉の第1の出銑時における溶銑面および溶銑の流れを説明する概略図、図4(B)は同高炉の第2の出銑時における溶銑面および溶銑の流れを説明する概略図、図5は活性状態にある高炉の第1および第2の出銑における出銑後経過時間と溶銑温度との関係を示すグラフ、図6(A)は不活性状態にある高炉の第1の出銑時における溶銑面および溶銑の流れを説明する概略図、図6(B)は同高炉の第2の出銑時における溶銑面および溶銑の流れを説明する概略図、図7は不活性状態にある高炉の第1および第2の出銑における出銑後経過時間と溶銑温度との関係を示すグラフ、図8は活性状態にあるものの、一時的に操業条件が変動した高炉の第1および第2の出銑における出銑後経過時間と溶銑温度との関係を示すグラフ、図9(A)は第1日午前0時から第11日午前0時までの高炉の操業時におけるT2t−T1bの経時変化を示すグラフ、図9(B)は同操業時における炉底部の耐火物内部に設置した温度計の測定値の経時変化を示すグラフである。
Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 is a schematic view of a blast furnace used in the method of operating a blast furnace according to an embodiment of the present invention, and FIG. 2 (A) is an output at the first brewery of the blast furnace in an active state. FIG. 2 (B) is a graph showing the relationship between post-elapsed time and the amount of stored hot metal in the same blast furnace, and FIG. 3 is in an active state. FIG. 4 (A) is a graph showing the relationship between the elapsed time after brewing and the hot metal temperature in the first brewing of a certain blast furnace, and FIG. FIG. 4B is a schematic diagram for explaining the hot metal surface and the flow of the hot metal at the time of the second extraction of the blast furnace, and FIG. 5 is a first and second extraction of the blast furnace in the active state. FIG. 6A is a graph showing the relationship between the elapsed time after brewing and the hot metal temperature in FIG. FIG. 6B is a schematic diagram for explaining the hot metal surface and the flow of the hot metal at the time of the first brewing, FIG. 6B is a schematic diagram for explaining the hot metal surface and the flow of the hot metal at the second time of the blast furnace, FIG. Fig. 8 is a graph showing the relationship between the elapsed time after unloading and the hot metal temperature in the first and second unloading of the blast furnace in the inactive state, and Fig. 8 shows the blast furnace in which the operating conditions have temporarily changed although in the active state FIG. 9 (A) is a graph showing the relationship between the elapsed time after brewing and the hot metal temperature in the first and second brewings of FIG. 9, and FIG. 9 (A) shows the operation time of the blast furnace from midnight on the first day to midnight on the 11th day FIG. 9B is a graph showing the change over time of the measured value of the thermometer installed inside the refractory at the bottom of the furnace during the operation.

図1に本発明の一実施の形態に係る高炉の操業方法に用いられる高炉10の概略図を示す。高炉10は、鉄製の容器の内面に耐火物19が貼られた筒状の反応炉である。耐火物19の外部には、図示しない冷却装置であるステーブが設置されている。高炉10の上部には、鉄鉱石、焼結鉱、ペレット等の鉄原料および燃料であるコークスを装入するための炉頂部11が設けられており、高炉10の下部の側面には、炉内に熱を供給するための熱風、および補完還元材である微粉炭を吹き込むための羽口12が設けられている。炉底部の側面、具体的には炉床湯溜部14の側壁には、貯留した溶銑を出銑するための第1の出銑口15および第2の出銑口16が設けられている。 FIG. 1 shows a schematic diagram of a blast furnace 10 used in a method for operating a blast furnace according to an embodiment of the present invention. The blast furnace 10 is a cylindrical reaction furnace in which a refractory 19 is attached to the inner surface of an iron container. A stave, which is a cooling device (not shown), is installed outside the refractory 19. A furnace top 11 for charging iron raw materials such as iron ore, sintered ore, pellets, and coke as fuel is provided at the upper part of the blast furnace 10. There are provided tuyere 12 for blowing hot air to supply heat and pulverized coal which is a complementary reducing material. On the side surface of the bottom of the furnace, specifically, on the side wall of the hearth hot water storage section 14, a first tap outlet 15 and a second tap outlet 16 for discharging the stored hot metal are provided.

第1の出銑口15および第2の出銑口16には、溶銑温度を測定するための図示しない温度計が配置されている。一定の間隔で溶銑温度の測定を行い、第1の出銑終了前20分間の測定値、および第2の出銑開始直後から20分間の測定値をそれぞれ平均し、第1の出銑の末期の溶銑温度T1b、および第2の出銑の初期の溶銑温度T2tとし、両者の差(T2t−T1b)を求める。温度の測定間隔は20分以下であり、好ましくは10分以下である。本実施の形態においては、1分間隔で測定を行った。
溶銑温度の測定には、1400〜1600℃の高温測定を行うことができる任意の温度計(熱電対を用いたもの等)を用いることができるが、例えば、特開2006−119110号公報に記載の、溶銑の熱放射輝度分布画像の濃度ヒストグラムの最頻値に基づいて溶銑温度を産出する高炉出銑温度測定装置等の非接触型の温度測定装置がより好ましい。
A thermometer (not shown) for measuring the hot metal temperature is disposed at the first and second tap outlets 15 and 16. The hot metal temperature is measured at regular intervals, and the measured value for 20 minutes before the end of the first brewing and the measured value for 20 minutes immediately after the start of the second brewing are averaged, respectively. The hot metal temperature T1b and the initial hot metal temperature T2t of the second brewing are obtained, and the difference between the two (T2t−T1b) is obtained. The temperature measurement interval is 20 minutes or less, preferably 10 minutes or less. In the present embodiment, measurement was performed at 1 minute intervals.
For the measurement of the hot metal temperature, any thermometer (such as one using a thermocouple) capable of performing high-temperature measurement at 1400 to 1600 ° C. can be used. For example, it is described in JP-A-2006-119110. A non-contact type temperature measuring device such as a blast furnace temperature measuring device that produces the hot metal temperature based on the mode value of the density histogram of the thermal radiance distribution image of the hot metal is more preferable.

高炉10内で熱風と接触したコークスは、燃焼により還元性ガスを生成し、接触した鉄鉱石中の酸化鉄を還元する。一方、高炉中央部のコークスは、コークス粒がほとんど流動せずに多孔状の炉芯13を形成し、滴下してきた液滴中に含まれる酸化物をさらに還元するとともに、高炉10内の熱源としても作用する。生成した鉄分は、高温により融解し、液滴となって高炉10内を滴下し、炉床湯溜部14に貯留するとともに、第1の出銑口15または第2の出銑口16より出銑される。
なお、鉄原料中に含まれるシリカやアルミナ等の不純物は、コークスや微粉炭中の灰分とともに溶融してスラグとなる。スラグの比重は、溶銑のそれよりも小さいため、スラグは溶銑上に浮上し、第1の出銑口15または第2の出銑口16から溶銑とともに排出後、分離される。
The coke in contact with the hot air in the blast furnace 10 generates a reducing gas by combustion, and reduces iron oxide in the iron ore that has come into contact. On the other hand, the coke at the center of the blast furnace forms a porous furnace core 13 with almost no coke grains flowing, further reducing the oxide contained in the dropped droplets, and as a heat source in the blast furnace 10 Also works. The generated iron content is melted at a high temperature, drops into the blast furnace 10 and is stored in the hearth hot water storage section 14 and is discharged from the first tap outlet 15 or the second tap outlet 16. I will be deceived.
Impurities such as silica and alumina contained in the iron raw material melt together with ash in coke and pulverized coal to form slag. Since the specific gravity of the slag is smaller than that of the hot metal, the slag floats on the hot metal and is separated from the first hot metal outlet 15 or the second hot iron outlet 16 after being discharged together with the hot metal.

本発明の一実施の形態に係る高炉の操業方法は、高炉10を用いて溶銑を製造するに際し、まず第1の出銑口15を開口して第1の出銑を行い、次いで第1の出銑口15を閉塞して第1の出銑を終了し、第2の出銑口16を開口して第2の出銑を行う操業において、第1の出銑の末期の溶銑温度T1bと、第2の出銑の初期の溶銑温度T2tとをそれぞれ測定し、T2t−T1b>−15℃となるように高炉10の操業条件を制御する。 In the method of operating a blast furnace according to an embodiment of the present invention, when producing hot metal using the blast furnace 10, first the first tap hole 15 is opened to perform the first tap iron, and then the first In the operation of closing the tap port 15 to finish the first tapping and opening the second tap port 16 to perform the second tapping, the hot metal temperature T1b at the end of the first taping The initial hot metal temperature T2t of the second feed is measured, and the operating conditions of the blast furnace 10 are controlled so that T2t−T1b> −15 ° C.

活性状態にある高炉10の第1の出銑における、出銑後経過時間と、溶銑の生成量および出銑量との関係を示すグラフを図2(A)に、出銑後経過時間と、炉床湯溜部14に貯留する溶銑の量(以下「貯留溶銑量」という)との関係を示すグラフを図2(B)にそれぞれ示す。
第1の出銑開始直後からしばらくの間は、貯留溶銑量が減少して溶銑面が第1の出銑口15よりも低下しており、溶銑の生成量が出銑量を上回っている。そのため、図2(B)に示すように貯留溶銑量は徐々に増加するが、溶銑面17の上昇に伴い、出銑量も次第に増大する(図2(A)中、aで示した領域)。
出銑開始後時間の経過とともに、第1の出銑口15は損耗して徐々に拡大するため、出銑量が増大し、生成量と出銑量が等しくなると、一時的に定常状態に到達し、図2(A)、および(B)に示すように出銑量および溶銑面17が一定に保たれる(図2(A)中、bで示した領域)。
第1の出銑の末期には、第1の出銑口15の損耗による拡大がさらに進み、出銑量が生成量を上回るため、図2(B)に示すように溶銑面17は低下し、第1の出銑口15の出銑口面に達した時点で第1の出銑を終了する(図2(A)中、cで示した領域)。
この際、高炉が活性状態にあれば、図2(A)に示すように、溶銑の生成量は、予め立てた操業計画によって設定された操業条件に応じたほぼ一定の値となる。
In FIG. 2 (A), a graph showing the relationship between the elapsed time after brewing, the amount of hot metal produced and the amount of brewing in the first brewing of the blast furnace 10 in the active state, Graphs showing the relationship with the amount of hot metal stored in the hearth hot water reservoir 14 (hereinafter referred to as “the amount of stored hot metal”) are shown in FIG.
For a while after the start of the first hot metal, the amount of hot metal stored has decreased and the hot metal surface has become lower than the first hot metal outlet 15, and the amount of hot metal produced exceeds the amount of hot metal. Therefore, the amount of stored molten iron gradually increases as shown in FIG. 2 (B), but the amount of molten iron gradually increases as the hot metal surface 17 rises (the region indicated by a in FIG. 2 (A)). .
As time passes after the start of tapping, the first tapping port 15 is worn out and gradually expands, so that the tapping amount increases, and when the generation amount and tapping amount become equal, the steady state is temporarily reached. As shown in FIGS. 2 (A) and 2 (B), the amount of molten iron and the molten iron surface 17 are kept constant (the region indicated by b in FIG. 2 (A)).
At the end stage of the first brewing process, the first brewing port 15 is further expanded due to wear and the amount of the brewing process exceeds the generated amount, so that the hot metal surface 17 is lowered as shown in FIG. When the first taphole 15 is reached, the first tapout is finished (region indicated by c in FIG. 2A).
At this time, if the blast furnace is in an active state, as shown in FIG. 2 (A), the amount of hot metal produced becomes a substantially constant value according to the operation conditions set in advance by an operation plan.

上で説明した活性な状態にある高炉10の、第1の出銑における出銑後経過時間と溶銑温度との関係を示すグラフを図3に示す。
第1の出銑の初期には、炉床湯溜部14に貯留した溶銑がほとんどないため、出銑開始直後には、生成後間もない高温の溶銑の一部が直接第1の出銑口15から出銑されるとともに、残りは炉床湯溜部14に貯留する。その後、時間の経過とともに貯留溶銑量が増大すると、貯留された溶銑の第1の出銑口15から出銑される溶銑全体に占める割合が次第に大きくなる。炉床湯溜部14に貯留した溶銑は、冷却され温度が低下しているので、出銑される溶銑温度は、時間とともに低下する(図3中、a’で示した領域)。
出銑量および溶銑面17が一時的に定常状態に到達すると、貯留された溶銑の第1の出銑口15から出銑される溶銑全体に占める割合も一定となるため、溶銑温度も一時的に一定の値となる(図3中、b’で示した領域)。
第1の出銑の末期には、貯留溶銑量および溶銑面17が低下するのに伴い、貯留された溶銑の第1の出銑口15から出銑される溶銑全体に占める割合が低下するため、第1の出銑口15から出銑される溶銑温度は再び上昇する(図3中、c’で示した領域)。
FIG. 3 shows a graph showing the relationship between the elapsed time after brewing and the hot metal temperature in the first brewing of the blast furnace 10 in the active state described above.
Since there is almost no hot metal stored in the hearth hot water storage section 14 at the initial stage of the first hot metal, immediately after the start of the hot metal, a part of the hot metal that has just been generated is directly added to the first hot metal. While being discharged from the mouth 15, the remainder is stored in the hearth hot water reservoir 14. Thereafter, when the amount of stored hot metal increases with the passage of time, the ratio of the stored hot metal to the entire hot metal discharged from the first outlet 15 gradually increases. Since the hot metal stored in the hearth hot water storage section 14 is cooled and the temperature is lowered, the hot metal temperature discharged decreases with time (the region indicated by a ′ in FIG. 3).
When the amount of hot metal and the hot metal surface 17 temporarily reach a steady state, the ratio of the hot metal stored in the hot metal discharged from the first hot metal outlet 15 becomes constant, so the hot metal temperature is also temporarily increased. (A region indicated by b 'in FIG. 3).
At the final stage of the first hot metal, the amount of the hot metal stored from the first hot metal outlet 15 decreases as the amount of hot metal stored and the hot metal surface 17 decrease. The hot metal temperature discharged from the first tap hole 15 rises again (region indicated by c ′ in FIG. 3).

活性状態にある高炉10の第1の出銑時における溶銑面17および溶銑の流れを説明する概略図、ならびに同高炉の第2の出銑時における溶銑面17および溶銑の流れを説明する概略図を、それぞれ図4(A)および図4(B)に示す。なお、「側面図」は、炉床部付近の概略図を、「断面図」は、炉床湯溜部14における断面図をそれぞれ意味する。
不透過層が存在しないため、溶銑は炉床湯溜部14の内部を円滑に流動することができる。したがって、溶銑面17の高さおよび溶銑温度は、上記のような経時変化を示す。
Schematic explaining the hot metal surface 17 and the flow of hot metal during the first brewing of the blast furnace 10 in the active state, and schematic diagram explaining the hot metal surface 17 and the flow of hot metal during the second brewing of the blast furnace Are shown in FIG. 4 (A) and FIG. 4 (B), respectively. The “side view” means a schematic view around the hearth part, and the “cross-sectional view” means a cross-sectional view at the hearth hot water reservoir 14.
Since there is no impermeable layer, the hot metal can smoothly flow inside the hearth hot water reservoir 14. Therefore, the height of the hot metal surface 17 and the hot metal temperature show the above-described change with time.

活性状態にある高炉10の、第1および第2の出銑における出銑後経過時間と溶銑温度との関係を示すグラフを図5に示す。
第1および第2の出銑における、出銑後経過時間と溶銑温度との関係については、上で説明したとおりである。本実施の形態にでは、第1の出銑終了後、第1の出銑口15を閉塞して5分後に第2の出銑口16を開口して、第2の出銑を開始している。上で説明した第1の出銑の場合と同様、第2の出銑の開始直後は、炉床湯溜部14に貯留した溶銑がほとんどないため、第2の出銑口16から出銑される溶銑の大部分は、生成後間もない高温の溶銑である。また、第1の出銑終了から第2の出銑開始までは5分間と短時間であり、その間大きな操業条件の変動も起こらなかったため、本実施の形態においては、T1b―T2t=0℃である。
高炉の操業状態が変動しない理想的な場合には、上述の如くT1b―T2t=0℃となるが、実際には、装入した原料の品質の変動等に起因して、生成する溶銑の温度は若干変動する。高炉の操業状態が活性状態にあれば、操業経験上、T2t−T1b>−15℃が成立することが確認されている。そこで、T2t−T1b>−15℃が常に成立するように高炉の操業条件を制御することとした。
FIG. 5 is a graph showing the relationship between the elapsed time after brewing and the hot metal temperature in the first and second brewings of the blast furnace 10 in the active state.
The relationship between the elapsed time after brewing and the hot metal temperature in the first and second brewings is as described above. In the present embodiment, after the first brewing is finished, the first brewing port 15 is closed, and after 5 minutes, the second brewing port 16 is opened to start the second brewing. Yes. As in the case of the first tapping described above, immediately after the start of the second tapping, since there is almost no hot metal stored in the hearth hot water storage section 14, it is tapped from the second tapping outlet 16. Most of the hot metal is hot hot metal that has just been formed. In addition, in this embodiment, T1b−T2t = 0 ° C., since it took a short time of 5 minutes from the end of the first tapping to the start of the second tapping, and during that time there was no significant change in operating conditions. is there.
In the ideal case where the operating condition of the blast furnace does not vary, T1b−T2t = 0 ° C. as described above, but in actuality, the temperature of the hot metal produced due to the variation in the quality of the charged raw materials, etc. Varies slightly. If the operating state of the blast furnace is in the active state, it has been confirmed from the operating experience that T2t-T1b> −15 ° C. is established. Therefore, the operating conditions of the blast furnace are controlled so that T2t−T1b> −15 ° C. is always established.

一方、不活性状態にある高炉10の第1の出銑時における溶銑面17および溶銑の流れを説明する概略図、ならびに同高炉の第2の出銑時における溶銑面17および溶銑の流れを説明する概略図を、それぞれ図6(A)および図6(B)に示す。なお、「側面図」は、炉床部付近の概略図を、「断面図」は、炉床湯溜部14における断面図をそれぞれ意味する。
炉床湯溜部14に不透過層18が生成すると、第1の出銑口15近傍から第2の出銑口16への溶銑の流動、および第2の出銑口16近傍から第1の出銑口15への溶銑の流動が阻害される。特に、図6(A)および(B)に示すように、第2の出銑口16近傍に不透過層18が生成すると、第1の出銑終了後も、図6(B)の側面図に示すように、第2の出銑口16近傍には溶銑が滞留する。
On the other hand, a schematic diagram explaining the hot metal surface 17 and the flow of hot metal during the first extraction of the blast furnace 10 in an inactive state, and the hot metal surface 17 and the flow of hot metal during the second extraction of the blast furnace are explained. Schematic diagrams to be shown are shown in FIGS. 6 (A) and 6 (B), respectively. The “side view” means a schematic view around the hearth part, and the “cross-sectional view” means a cross-sectional view at the hearth hot water reservoir 14.
When the impervious layer 18 is generated in the hearth hot water reservoir 14, the hot metal flow from the vicinity of the first outlet 15 to the second outlet 16, and from the vicinity of the second outlet 16 to the first outlet The flow of hot metal to the spout 15 is inhibited. In particular, as shown in FIGS. 6A and 6B, when the impermeable layer 18 is generated in the vicinity of the second tap opening 16, the side view of FIG. As shown, the hot metal stays in the vicinity of the second spout 16.

上に述べたような、不活性状態にある高炉10の第1および第2の出銑における出銑後経過時間と溶銑温度との関係を示すグラフを図7に示す。
上で説明した場合と同様に、第1の出銑終了から5分後に第2の出銑を開始したにもかかわらず、T2tはT1bに対し大幅に低下している(T2t−T1b=−30℃)。T2t−T1b≦−15℃となる場合、図7に示すように、高炉内の炉芯13や炉床湯溜部14の一部に溶銑の流動を阻害する不透過層が生成し、第2の出銑口16近傍の炉床湯溜部14に溶銑が滞留するため、これが第2の出銑の開始直後において、生成後間もない溶銑とともに出銑される。そのため、T2tは、T1bよりも大幅に低下する。
このように、T2tとT1bとの関係(T2t−T1b)は、高炉の不活性状態に起因する炉芯13および炉床湯溜部14における不透過層の生成を如実に反映して変化するため、T2t−T1bを指標とすることにより、高炉の操業状態を迅速かつ的確に把握することができる。
FIG. 7 shows a graph showing the relationship between the elapsed time after brewing and the hot metal temperature in the first and second brewings of the blast furnace 10 in the inactive state as described above.
Similar to the case described above, T2t is significantly lower than T1b (T2t−T1b = −30) even though the second output starts 5 minutes after the end of the first output. ° C). When T2t−T1b ≦ −15 ° C., as shown in FIG. 7, an impervious layer that inhibits the flow of hot metal is generated in a part of the core 13 and the hearth hot water reservoir 14 in the blast furnace, Since the hot metal stays in the hearth hot water reservoir 14 in the vicinity of the hot metal outlet 16, the hot metal is discharged together with the hot metal immediately after generation, immediately after the start of the second hot metal. Therefore, T2t is significantly lower than T1b.
As described above, the relationship between T2t and T1b (T2t−T1b) changes to reflect the generation of the impermeable layer in the furnace core 13 and the hearth hot water reservoir 14 due to the inert state of the blast furnace. By using T2t-T1b as an index, the operating state of the blast furnace can be grasped quickly and accurately.

これに対して、特許文献1(特開平11−222611号公報の6〜7頁)に記載の炉芯活性状態の判定方法では、出銑初期の溶銑温度から当該出銑期間中の最低または最高溶銑温度を差し引いた値ΔTがゼロまたは正の値である状態が続く限り、高炉の操業状態は活性状態であると判定される。したがって、同方法によると、図7中の第2の出銑において、現実には不活性状態になっているにもかかわらず、第2の出銑開始後に溶銑温度が低下しているためΔT≧0となり、活性状態と誤判定される。 On the other hand, in the method for determining the core active state described in Patent Document 1 (Japanese Patent Laid-Open No. 11-222611, pages 6 to 7), the minimum or maximum during the brewing period from the hot metal temperature at the beginning of brewing. As long as the state ΔT obtained by subtracting the hot metal temperature continues to be zero or a positive value, the operating state of the blast furnace is determined to be an active state. Therefore, according to the same method, since the hot metal temperature is lowered after the start of the second brewing in the second brewing in FIG. It becomes 0 and it is erroneously determined as an active state.

図8は、活性状態にあるものの、一時的に操業条件が変動した高炉10の第1および第2の出銑における出銑後経過時間と溶銑温度との関係を示すグラフである。第1の出銑の中期以降、溶銑温度が低下しているが、これは、炉芯13や炉床湯溜部14における不透過層の発生によるものではなく、装入する原料の品質の一時的な低下や付着物の脱落等による操業条件の一時的な変動に起因するものである。このような場合には、高炉10の内部で生成する溶銑の温度の低下に伴い溶銑温度も一時的に低下するが、装入する原料品質の改善や、付着物を溶解させるために一時的に余剰の熱量を補填する等の措置を講じることにより、数時間程度で(図8の例では、第2の出銑終了時までに)操業状態は改善され、溶銑温度も上昇する。
このような、高炉10の炉口および炉腹部における一時的な操業状態の変化に起因して、溶銑温度が出銑開始後時間の経過とともに単調増加する、図8中の第2の出銑のような場合、特許文献1に記載の炉芯活性状態の判定方法では、出銑開始直後の温度が第2の出銑期間中の最低温度であるため、ΔT<0となり、不活性状態であると誤判定されることとなる。それに対して、出銑量の低下や装入原料中の還元材費の増大等の不適切な措置を講じると、却って高炉の操業状態の悪化や生産効率の低下を招くおそれがある。
FIG. 8 is a graph showing the relationship between the elapsed time after the brewing and the hot metal temperature in the first and second brewings of the blast furnace 10 in which the operating conditions are temporarily changed although they are in the active state. Although the hot metal temperature has decreased since the middle stage of the first brewing, this is not due to the generation of an impermeable layer in the furnace core 13 or the hearth hot water reservoir 14, but the temporary quality of the raw material charged. This is due to temporary fluctuations in operating conditions due to a general decline or drop of deposits. In such a case, the hot metal temperature temporarily decreases as the temperature of the hot metal generated inside the blast furnace 10 decreases. However, temporarily, in order to improve the quality of the raw material to be charged and to dissolve the deposits, By taking measures such as supplementing the surplus amount of heat, the operating state is improved and the hot metal temperature rises within a few hours (by the end of the second cooking in the example of FIG. 8).
Due to such a temporary change in the operating state at the furnace port and the abdominal part of the blast furnace 10, the hot metal temperature increases monotonically with the passage of time after the start of the hot metal. In such a case, in the determination method of the core active state described in Patent Document 1, since the temperature immediately after the start of tapping is the lowest temperature during the second tapping period, ΔT <0, which is an inactive state. Will be erroneously determined. On the other hand, if an inappropriate measure such as a decrease in the amount of feed and an increase in the cost of reducing material in the charged raw material is taken, there is a risk that the operating condition of the blast furnace will deteriorate and the production efficiency will decrease.

次に、炉芯13または炉床湯溜部14が不活性状態であると判定した場合に講じる措置(操業アクション)について説明する。
高炉10が不活性状態に移行し始め、炉芯13または炉床湯溜部14に不透過層が生成した場合、不透過層を消失させるために取り得る操業アクションとしては、(1)高炉10内への投入熱量を増大させて不透過層を直接加熱して融解する方法、および(2)不透過層の近傍に高温の溶銑を流通させ、溶銑の熱量により不透過層を融解する方法が挙げられる。
操業アクションの具体例としては、炉頂部11から装入する原料中のコークス比を増大させ、炉芯13および炉床湯溜部14により高い燃焼熱を投入するとともに、不透過層の近傍に、空隙率の大きいコークスにより通気性および通液性の高い領域を生成する方法、および微粉炭の吹込み量の増大または熱風の送風温度の増大により高炉10内への投入熱量を増大させる方法が挙げられる。
Next, a measure (operation action) taken when it is determined that the furnace core 13 or the hearth hot water reservoir 14 is in an inactive state will be described.
When the blast furnace 10 starts to enter an inactive state and an impervious layer is generated in the furnace core 13 or the hearth hot water storage part 14, the following actions can be taken to eliminate the impermeable layer: (1) blast furnace 10 (2) A method in which high temperature hot metal is circulated in the vicinity of the impermeable layer and the impermeable layer is melted by the amount of heat of the molten iron. Can be mentioned.
As a specific example of the operation action, the coke ratio in the raw material charged from the furnace top portion 11 is increased, high combustion heat is input from the furnace core 13 and the hearth hot water storage portion 14, and in the vicinity of the impermeable layer, Examples include a method of generating a region with high air permeability and liquid permeability by coke having a large porosity, and a method of increasing the amount of heat input into the blast furnace 10 by increasing the amount of pulverized coal blown or the temperature of hot air blowing. It is done.

これらの操業アクションは、それぞれ単独で行ってもよく、任意の2または3を組み合わせて行ってもよい。また、T2t−T1bの値に応じて、行う操業アクションの種類またはその組み合わせ、ならびにコークス比、微粉炭の吹込み量、および熱風の送風温度の増大量を予め決定しておいてもよい These operation actions may be performed alone or in combination of any two or three. Further, depending on the value of T2t-T1b, the type of operation action to be performed or a combination thereof, and the coke ratio, the amount of pulverized coal, and the amount of increase in the blowing temperature of hot air may be determined in advance.

次に、本発明の作用効果を確認するために行った実施例について説明する。
使用した高炉は、36本の羽口および4本の出銑口を有する、内容積4250mの溶鉱炉である。4本の出銑口のうち、対向する1対の出銑口から交互に出銑を行った。
高炉の操業条件は下記のとおりである。
出銑量:9800〜10150t/日
コークス比:330〜370kg/ton−pig
微粉炭吹込み量:130〜170kg/ton−pig
送風温度:1140〜1240℃
送風量:6200〜6600Nm/分
Next, examples carried out for confirming the effects of the present invention will be described.
The blast furnace used was a blast furnace with an internal volume of 4250 m 3 having 36 tuyere and 4 taps. Out of the four taps, the taps were alternately conducted from a pair of facing taps.
The operating conditions of the blast furnace are as follows.
Milling amount: 9800-10150 t / day Coke ratio: 330-370 kg / ton-pig
Amount of pulverized coal injection: 130-170 kg / ton-pig
Air temperature: 1140-1240 ° C
Air flow: 6200-6600 Nm 3 / min

溶銑温度は、第1および第2の出銑口の近傍で、特開2006−119110号公報に記載の高炉出銑温度測定装置を用いて測定した。測定は1分間隔で行い、第1の出銑終了前20分間の測定値、および第2の出銑開始直後から20分間の測定値をそれぞれ平均し、T1b、T2tおよび両者の差(T2t−T1b)を求めた。
また、比較のため、高炉の炉底部の耐火物内部に設置した温度計を用いて、炉底温度を計測した。
The hot metal temperature was measured in the vicinity of the first and second tap outlets using a blast furnace hot strip temperature measuring apparatus described in JP-A-2006-119110. Measurements are taken at 1-minute intervals, and the measured values for 20 minutes before the end of the first brewing and the measured values for 20 minutes immediately after the start of the second brewing are averaged, and T1b, T2t and the difference between them (T2t− T1b) was determined.
For comparison, the bottom temperature was measured using a thermometer installed inside the refractory at the bottom of the blast furnace.

上記のようにして得られたT2t−T1bの値に応じて、コークス比を増大させる操業アクションを行った。T2t−T1bの値とコークス比の増大量との関係は、以下の表1に示すとおりとした。 The operation action which increases a coke ratio was performed according to the value of T2t-T1b obtained as mentioned above. The relationship between the value of T2t−T1b and the amount of increase in the coke ratio was as shown in Table 1 below.

Figure 2008255402
Figure 2008255402

図9(A)に、第1日午前0時から、第11日午前0時までの高炉の操業時における、T2t−T1bの経時変化を示す。T2t−T1bの値は、第2日の午前0時(図9(A)中、(1)で示した時点)に−15℃を下回っており、この時点で高炉が不活性状態に移行したと判定された。そこで、上記表1にしたがい、高炉に装入する原料のコークス比を増大させる操業アクションを講じた。
T2t−T1bの値は、第3日の夜には−32℃付近まで低下したが、第5日の夜(図9(A)中、(2)で示した時点)までには−15℃以上の値に改善され、不活性状態は約4日間で活性状態に改善された。
FIG. 9A shows the change over time of T2t-T1b during the operation of the blast furnace from midnight on the first day to midnight on the eleventh day. The value of T2t-T1b was below −15 ° C. at midnight (the time indicated by (1) in FIG. 9A) on the second day, and the blast furnace shifted to an inactive state at this time. It was determined. Therefore, in accordance with Table 1 above, an operation action was taken to increase the coke ratio of the raw material charged into the blast furnace.
The value of T2t-T1b decreased to around −32 ° C. on the third night, but was −15 ° C. by the fifth day (the time indicated by (2) in FIG. 9A). The inactive state was improved to the active state in about 4 days.

同操業時における、炉底部の耐火物内部に設置した温度計の測定値の経時変化を図9(B)に示す。炉底温度が低下に転じたのは、実際に不活性状態に移行してから約2日後の第4日の午前0時頃(図9(B)中、(3)で示した時点)である。また、炉底温度が上昇に転じたのは、活性状態に回復後約2日後の第7日の夜間(図9(B)中、(4)で示した時点)である。このことから、炉底温度の変化を指標とする従来の方法に比べ、本発明の方法では、迅速に高炉の操業状態の変化を把握できることがわかる。
本発明の方法と、炉底温度を指標とする従来の方法をそれぞれ用いた場合における、出銑量、コークス比、および活性状態回復までに要した日数を比較した結果を、以下の表2に示す。
FIG. 9B shows the change over time in the measured value of the thermometer installed in the refractory at the bottom of the furnace during the operation. The temperature at the bottom of the furnace started to decrease at around midnight on the fourth day (the time indicated by (3) in FIG. 9B) about two days after the actual transition to the inactive state. is there. Further, the furnace bottom temperature started to increase at night of the seventh day (the time indicated by (4) in FIG. 9B) about two days after the recovery to the active state. From this, it can be seen that the change of the operating state of the blast furnace can be quickly grasped by the method of the present invention as compared with the conventional method using the change of the furnace bottom temperature as an index.
Table 2 below shows the results of comparing the amount of tapping, the coke ratio, and the number of days required to recover the active state when using the method of the present invention and the conventional method using the furnace bottom temperature as an index. Show.

Figure 2008255402
Figure 2008255402

本発明の方法によると、出銑量の減少幅、およびコークス比の増大量を抑制しつつ、より短期間で高炉の操業状態を改善できることがわかる。 According to the method of the present invention, it can be seen that the operating state of the blast furnace can be improved in a shorter period of time while suppressing the decrease amount of the amount of brewing and the increase amount of the coke ratio.

本発明は、前記した実施の形態に限定されるものではなく、本発明の要旨を変更しない範囲での変更は可能であり、例えば、前記した実施の形態や変形例の一部または全部を組み合わせて本発明の高炉の操業方法を構成する場合も本発明の権利範囲に含まれる。
例えば、前記実施の形態の高炉の操業方法において、2本の出銑口を用いて出銑を行っているが、3本以上の出銑口を用いて出銑を行う場合にも本発明の高炉の操業方法を同様に適用することができる。
The present invention is not limited to the above-described embodiment, and can be changed without changing the gist of the present invention. For example, a part or all of the above-described embodiment and modification examples are combined. Thus, the case where the operation method of the blast furnace of the present invention is configured is also included in the scope of the right of the present invention.
For example, in the method of operating a blast furnace according to the above-described embodiment, the tapping is performed using two tapping outlets, but also when tapping is performed using three or more tapping outlets, Blast furnace operating methods can be applied as well.

本発明の一実施の形態に係る高炉の操業方法に用いられる高炉の概略図である。It is the schematic of the blast furnace used for the operating method of the blast furnace which concerns on one embodiment of this invention. (A)は活性状態にある高炉の第1の出銑における出銑後経過時間と溶銑の生成量および出銑量との関係を示すグラフであり、(B)は同高炉における出銑後経過時間と貯留溶銑量との関係を示すグラフである。(A) is a graph showing the relationship between the elapsed time after brewing in the first brewing of the blast furnace in the active state, the amount of hot metal produced and the amount of brewing, and (B) is the elapsed time after brewing in the blast furnace. It is a graph which shows the relationship between time and the amount of stored hot metal. 活性状態にある高炉の第1の出銑における出銑後経過時間と溶銑温度との関係を示すグラフである。It is a graph which shows the relationship between the elapsed time after the extraction in the 1st extraction of the blast furnace in an active state, and the hot metal temperature. (A)は活性状態にある高炉の第1の出銑時における溶銑面および溶銑の流れを説明する概略図であり、(B)は同高炉の第2の出銑時における溶銑面および溶銑の流れを説明する概略図である。(A) is a schematic diagram explaining the hot metal surface and the flow of hot metal during the first brewing of the blast furnace in an active state, and (B) is the hot metal surface and hot metal flow during the second brewing of the blast furnace. It is the schematic explaining a flow. 活性状態にある高炉の第1および第2の出銑における出銑後経過時間と溶銑温度との関係を示すグラフである。It is a graph which shows the relationship between the elapsed time after the brewing and the hot metal temperature in the 1st and 2nd brewing of the blast furnace in an active state. (A)は不活性状態にある高炉の第1の出銑時における溶銑面および溶銑の流れを説明する概略図であり、(B)は同高炉の第2の出銑時における溶銑面および溶銑の流れを説明する概略図である。(A) is the schematic explaining the hot metal surface and the flow of hot metal in the first brewing of the blast furnace in an inactive state, (B) is the hot metal surface and hot metal in the second brewing of the blast furnace. It is the schematic explaining the flow. 不活性状態にある高炉の第1および第2の出銑における出銑後経過時間と溶銑温度との関係を示すグラフである。It is a graph which shows the relationship between the elapsed time after the brewing in the 1st and 2nd brewing of the blast furnace in an inactive state, and hot metal temperature. 活性状態にあるものの、一時的に操業条件が変動した高炉の第1および第2の出銑における出銑後経過時間と溶銑温度との関係を示すグラフである。It is a graph which shows the relationship between the elapsed time after the brewing and the hot metal temperature in the 1st and 2nd brewing of the blast furnace which was in the active state, but the operation conditions were temporarily changed. (A)は第1日午前0時から第11日午前0時までの高炉の操業時におけるT2t−T1bの経時変化を示すグラフであり、(B)は同操業時における炉底部の耐火物内部に設置した温度計の測定値の経時変化を示すグラフである。(A) is a graph showing the change over time of T2t-T1b during the operation of the blast furnace from midnight on the first day to midnight on the first day, and (B) is the inside of the refractory at the bottom of the furnace during the same operation It is a graph which shows the time-dependent change of the measured value of the thermometer installed in.

符号の説明Explanation of symbols

10:高炉、11:炉頂部、12:羽口、13:炉芯、14:炉床湯溜部、15:第1の出銑口、16:第2の出銑口、17:溶銑面、18:不透過層、19:耐火物 10: blast furnace, 11: furnace top, 12: tuyere, 13: furnace core, 14: hearth hot water reservoir, 15: first tap outlet, 16: second tap outlet, 17: hot metal surface, 18: Impervious layer, 19: Refractory

Claims (4)

炉底部側面に第1および第2の出銑口を有する高炉を用いて溶銑を製造するに際し、まず前記第1の出銑口を開口して第1の出銑を行い、その後、前記第2の出銑口を開口して第2の出銑を行う高炉の操業において、前記第1の出銑の末期の溶銑温度T1bと、前記第2の出銑の初期の溶銑温度T2tとをそれぞれ測定し、T2t−T1b>−15℃となるように前記高炉の操業条件を制御することを特徴とする高炉の操業方法。 When producing hot metal using a blast furnace having first and second tap holes on the side of the furnace bottom, first the first tap hole is opened to perform the first tapping, and then the second In the operation of the blast furnace in which the first tap iron is opened and the second tap iron is opened, the final hot metal temperature T1b of the first tap iron and the initial hot metal temperature T2t of the second tap iron are measured. And the operating condition of the said blast furnace is controlled so that it may become T2t-T1b> -15 degreeC, The operating method of the blast furnace characterized by the above-mentioned. 請求項1記載の高炉の操業方法において、T2t−T1b≦−15℃である場合、前記高炉内に装入する原料中のコークス比を増大させることを特徴とする高炉の操業方法。 The blast furnace operating method according to claim 1, wherein when T2t−T1b ≦ −15 ° C., the coke ratio in the raw material charged into the blast furnace is increased. 請求項1および2のいずれか1項に記載の高炉の操業方法において、T2t−T1b≦−15℃である場合、前記高炉内の微粉炭の吹込み量を増大させることを特徴とする高炉の操業方法。 The method of operating a blast furnace according to any one of claims 1 and 2, wherein when T2t-T1b≤-15 ° C, the amount of pulverized coal injected into the blast furnace is increased. Operation method. 請求項1〜3のいずれか1項に記載の高炉の操業方法において、T2t−T1b≦−15℃である場合、前記高炉内の送風温度を増大させることを特徴とする高炉の操業方法。 The operating method of the blast furnace of any one of Claims 1-3 WHEREIN: When it is T2t-T1b <=-15 degreeC, the ventilation temperature in the said blast furnace is increased, The operating method of the blast furnace characterized by the above-mentioned.
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CN112257590B (en) * 2020-10-22 2023-08-01 中冶南方工程技术有限公司 Automatic detection method, system and storage medium for working state of blast furnace tap hole

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