JP4184633B2 - Blast furnace extraction method - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は、高炉炉床部での銑滓貯留レベルの上昇に伴う操業トラブルを回避し安定操業を行うための高炉の出銑滓方法に関するものである。
【０００２】
【従来の技術】
高炉の炉床における銑滓貯留レベルの把握は操業管理上重要である。
スラグレベルが所定以上に上昇すると、送風圧力変動が大きくなり安定的な操業状態が維持できなくなり、特に、スラグレベルが送風羽口レベルまで上昇してしまうと、スラグが羽口を閉塞してしまい操業不能となる。
【０００３】
一般に、炉内の貯銑滓レベルは、銑滓の生成と排出との物質収支より大凡推定できる。例えば、銑滓の生成量は、単位時間あたりに高炉に装入した装入物の量とその成分から計算でき、銑滓の排出量は、銑鉄を収容するトーピードカーの重量変化を測定したり、スラグから製造した水滓の重量をスケールコンベア−などによって測定できるため、これらの銑滓の生成量と排出量の差分により炉内の銑滓量の増加量を推定できる。
【０００４】
特開平７−１５０２１０号には、プロセスコンピュータを用いて出銑加速度を計算し現在の出銑状態が初期、安定期、後期及び終了期のいずれに属するかを判定し、出銑終了時刻を予測する方法が開示されているが、この方法も基本的には上記の物質収支に立脚した炉内残銑滓量の推定方法を利用した技術である。
【０００５】
一方、物質収支による炉内残銑滓量の推定方法を用いずに銑滓の検出器を用いて銑滓レベルを測定する方法としては、例えば、特開昭５３−８６２４２号には、高炉の炉床部炉壁に、陽極と陰極からなる一対の棒状黒鉛電極を高さ方向に複数配列してそれぞれ電気的に回路を構成して通電し、溶銑が一対の棒状黒鉛電極に接触したときの導通をパイロットランプまたは電流計で検知することにより銑滓レベルを測定する方法が開示されている。
【０００６】
また、特開昭５９−１４０３０９号では、高炉の炉底付近の炉壁を構成する煉瓦に、少なくとも１対の電極を設けて四端子測定法による抵抗測定系（ダブルブリッヂ系）電気回路を構成し、電気抵抗の測定値から銑滓レベルを測定する方法が開示されている。
【０００７】
【発明が解決しようとする課題】
上記の特開平７−１５０２１０号等の物質収支による炉内残銑滓量の推定方法では、銑滓生成量は装入した鉱石類が直ちに溶融することを前提に計算するが、溶解までには少なくとも数時間のタイムラグがあるばかりでなく成分分析値を元に計算を行うために、その分析値の精度、代表性、ばらつきなどによっても誤差が生じる。
【０００８】
また銑滓排出量は、スラグなどの直接的な秤量は行われておらず、水滓化した後のものをスケールコンベア−などで秤量する程度であり、その誤差は少なくとも１０％程度あるといわれている。このため、物質収支により銑滓レベルを推定する際には大きな誤差を前提に安全代を大きくとった対応が不可欠である。
【０００９】
また、特開昭５３−８６２４２号の銑滓レベルを測定方法は、銑滓の通電を測定するために少なくとも一対の電極を銑滓に接触するように炉内に挿入して配置する必要があるため、電極表面に銑滓の冷却により形成される凝固層およびその厚み変動により通電状態が変動し信頼性のある炉内銑滓レベルの測定データを得ることは困難である。
また、この方法では、電極を炉底部の炉壁を貫通させて設置するために電極溶損時にはその部分から溶銑が流れ出し炉底破損といった大事故を招く可能性がある。
【００１０】
また、特開昭５９−１４０３０９号の銑滓レベルの測定方法は、煉瓦と銑滓の電気抵抗を測定するため、煉瓦の経時的な劣化や銑滓の煉瓦への侵入等に起因する煉瓦の導電性の変動、および煉瓦近傍の銑滓温度や銑滓の凝固状態または流動状態に起因する銑滓の導電性の変動などにより煉瓦と銑滓の電気抵抗の測定値は変動し信頼性のある炉内銑滓レベルの測定データを得ることは困難である。
【００１１】
このように、従来の技術において、炉内の貯銑滓量および貯銑滓レベルを充分な精度、高い信頼性をもって計測できる方法はなく、銑滓排出不足に起因して大幅な減風を余儀なくされたり羽口がスラグで閉塞する等の操業トラブルが発生していた。このため、炉内の貯銑滓状況を連続的に信頼性高く把握し、より早くアクションを取ることができる方法の開発が望まれていた。
【００１２】
本発明は、高炉の炉底部における貯銑滓レベルを連続的に高い信頼性で測定し、この測定値をもとに銑滓貯留レベルの上昇に伴う操業トラブルを回避し安定操業を行うための高炉の出銑滓方法を提供することを目的とする。
【００１３】
【課題を解決するための手段】
本発明は、上記の課題を解決するものであり、その要旨とするところは、以下の通りである。
（１） 高炉炉体の外壁に、複数個の検出接点を、２個の検出接点で１対の電位差測定用の検出端となるように、炉底部の外壁鉄皮の底盤レベルから羽口レベルの高さ方向にかけて、所定距離隔て取り付け、底盤レベル近傍に設けた最下段の検出接点を基準とし、該検出接点と、それよりも高い位置の検出接点との電位差を測定し、該電位差の測定値が予め定めた設定値を超えた時に、銑滓生成速度を減少させる操業アクションおよび銑滓排出速度を増加させる操業アクションの何れか一方または両方を実施することを特徴とする高炉出銑滓方法。
（２） 前記複数個の検出接点の内、少なくとも１個の取り付け位置を出銑口レベル以上とし、他の検出接点の内、少なくとも１個の取り付け位置を出銑口レベル未満とすることを特徴とする（１）に記載の高炉出銑滓方法。
【００１４】
（３）前記銑滓生成速度を減少させる操業アクションとして、羽口送風量を減少させる（１）または（２）の何れかに記載の高炉出銑滓方法。
（４）前記銑滓排出速度を増加させる操業アクションとして、出銑時の出銑口の径を拡大するか、または複数の出銑口を同一時期に開口するか、何れかまたは両方を行う（１）または（２）の何れかに記載の高炉出銑滓方法。
【００１５】
【発明の実施の形態】
以下に本発明の詳細を説明する。
本発明者らは、高炉炉床部を中心に高炉炉体の電位を測定したところ、（１）極めて微弱ではあるが高さ方向に電位分布を持っていること、（２）高さ方向での電位差は炉内銑滓のレベルの変動に応じて増減すること、（３）同一銑滓レベルであればほぼ同じ電位差を示すことなどが分かった。
【００１６】
高炉炉体の高さ方向に電位差が生じる原因の詳細は不明であるが、本発明者らの考えでは、炉内に貯留している銑滓中の上層の比重の小さいスラグと下層の比重の重い溶銑間で電池を形成し、銑滓の量、高さ方向のレベルの変動に応じて炉壁部で観察される電位が変化するものと推察される。
【００１７】
本発明は、これらの知見を基になされたものであり、高炉炉体に少なくとも２個（複数個）の検出接点を高さ方向で所定距離隔て取り付け、前記検出接点間の電位差を測定し、該電位差の測定値が予め定めた設定値を超えた時に、銑滓生成速度を減少させる操業アクションおよび銑滓排出速度を増加させる操業アクションの何れか一方または両方を実施することを特徴とするものである。
【００１８】
また、上記複数個の検出接点の取り付け位置は、スラグと溶銑の境界面を挟むように各検出接点を配設した検出接点間の電位差を測定するのが望ましく、その目安として検出接点の内、少なくとも１個の取り付け位置を出銑口レベル以上とし、他の検出接点の内、少なくとも１個の取り付け位置を出銑口レベル未満とするのが望ましい。
【００１９】
本発明は、操業状態に応じて高炉内の銑滓に自然に発生する電流に起因して、高炉の高さ方向に所定の間隔で設けられた複数個の検出接点間の電位差を電圧計などを用いて測定するものであるから、従来技術のように少なくとも１対の電極と電気的回路を構成して強制的に通電する必要はなく、また、炉内の銑滓に直接通電させるために炉壁を貫通させて電極を設置し銑滓を接触させる必要もない。したがって、従来技術のような電極表面に銑滓の冷却により形成される凝固層およびその厚み変動などにより通電状態が変動し銑滓レベルの測定データの信頼性が低下するような問題はない。
【００２０】
本発明の実施形態の一例として、図１に電位差測定用の検出接点の配置図を、図２に電位差の測定結果を示す。
図１に示すように２個の検出接点で１対の電位差測定用の検出端となるように、高炉炉底部の外壁鉄皮の底盤レベルから羽口レベルの高さ方向にかけて複数個の検出接点を設置する。炉内の銑滓レベルは、スラグと溶銑の境界面を挟むように各検出接点を配設した検出接点間の電位差を測定することで可能であるが、より感度の高い測定を行うためには、底盤レベル近傍に電位の基準となる検出接点▲１▼を設け、最下段の検出接点▲１▼を基準とし、それよりも高い位置に配置された各検出接点▲２▼〜▲５▼との電位差を測定することが好ましい。
【００２１】
図２は、検出接点▲１▼と各検出接点▲２▼〜▲５▼との電位差を経時的に測定した結果である。なお、図２横軸の時刻には、Ｎｏ．１出銑口およびＮｏ．２出銑口の開口から閉鎖までの出銑時間を示す。
図２から基準である検出接点▲１▼との高さ方向の距離が長くなるほど、検出接点間の電位差が大きくなり最大で数百μＶの電位差が観察される。また、経時的には、出銑口径が小さく出銑速度の遅い出銑初期や出銑を行っていない期間は電位差が上昇し、銑滓レベルが低下する出銑の終了時点では電位差は小さくなり傾向にあり、出銑周期と連動する炉内の貯留銑滓レベルに依存して電位差が変化することが分かる。
【００２２】
炉内の貯留銑滓レベルと電位差との関係をより明確にするために、全ての出銑口を閉塞して一定時間溶銑の排出を停止し、その間の電位差の経時的変化を調べた。その結果の例として、図３に出銑待ち時間と電位差増加幅（出銑口の閉塞時の電位差を基準とする電位差の増加幅）との関係を示す。
出銑待ち時間の増加とともに電位差増加幅は増加し、高炉炉体の高さ方向の電位差と炉底部の残銑滓量と良い相関があることが分かる。
【００２３】
図４に、出銑の終了時点を０とし物質収支を基にした計算から求めた炉内残銑滓量（計算値）と、出銑の終了時点での電位差を基準とする炉底の電位差の増加幅との関係を示す。
計測された電位差増加幅（測定値）と物質収支を基にした計算から求めた炉内残銑滓量（計算値）は概ね正の相関を示しているが、図３の電位差増加幅（測定値）と出銑待ち時間（炉内残銑滓量）との関係に比べてデータのばらつきが大きく、これは主に物質収支を基に計算で求めた残銑滓量の不確定さに由来するものと考えられる。
【００２４】
以上より、高炉操業中に炉体高さ方向の電位差を連続的に測定することにより従来よりも信頼性の高い炉内貯留銑滓レベルの測定が可能となると共に、この電位差を予め設定した所定値以下にするように操業管理することで炉内銑滓レベルの上昇に伴うトラブルを回避することが可能となる。
【００２５】
高炉操業中に炉体高さ方向の電位差の測定値が予め定めた設定値を超えた場合には、炉内貯留銑滓レベルを低下させるために、銑滓生成速度を減少させる操業アクションおよび銑滓排出速度を増加させる操業アクションの何れか一方または両方を実施すればよい。
銑滓生成速度は、高炉の生産速度そのものであり、単位時間あたりの送風量を増減することにより変化させることが可能である。したがって、銑滓生成速度を減少させる操業アクションとしては、羽口送風量を減少させる方法を用いるとよい。
【００２６】
また、銑滓排出速度を増加させる操業アクションとしては、出銑で使用中の出銑口の径を大きな錐で掘削して拡大したり（促進開口）、出銑で使用中の出銑口の他に、他の閉塞している出銑口を開口して複数の出銑口で同時出銑する（ラップ出銑）などの方法により、単位時間当たりの出銑量を増加させる方法が用いることができる。
【００２７】
銑滓生成速度を減少させる操業アクションおよび銑滓排出速度を増加させる操業アクションの何れか一方または両方を実施するか否かを判定するための予め定めた電位差の設定値は、高炉の操業実績と電位差の測定値との関係、および操業トラブルに至ることなく、早期回復が可能な操業アクションのタイミングをもとに高炉オペレータが予め定めればよい。
【００２８】
具体的には、炉内残銑滓量の増加に起因して送風圧力変動が大きくなる直前の電位差を過去の実績から求め、その値もしくはその値に安全率を考慮して設定値を決めたり、一定時間出銑を停止して上昇した電位差の経時的変化をもとに決められる。
【００２９】
【実施例】
本発明例として、炉内容積３２７３ｍ3 、炉床径１２．０ｍの高炉を用いて、この炉体の出銑口から５ｍ下方の炉底カーボン煉瓦１段レベルと、出銑口から３．８ｍ上方の羽口と同一レベルにそれぞれ検出接点を設置し、これらの検出接点間の電位差を連続的に測定し、この電位差の測定値をもとに操業アクションを行った。
【００３０】
操業アクションとしては、電位差の測定値が設定値：０．７ｍＶに達すると、出銑で使用中の出銑口の径を大きな錐で掘削して拡大したり（促進開口）、出銑で使用中の出銑口の他の閉塞している出銑口を開口して複数の出銑口で同時出銑（ラップ出銑）のアクションを行い、設定値：０．７５ｍＶに達するとそれらアクションに加えて１０％の減風を実施することとした。
【００３１】
上記設定値：０．７ｍＶの決定理由は、高炉実操業において残銑滓量の増加に起因して送風圧力変動が大きくなる直前の電位差を１ヶ月間調べ、その平均電位差：０．７５ｍＶと標準偏差：０．５ｍＶの差から０．７ｍＶとした。
なお、銑滓レベルが出銑口レベルまで低下したときの電位差は約０．４ｍＶであり、したがって、電位差の測定値は０．４〜０．７ｍＶの間で変化する。
【００３２】
本発明を適用した結果、表１に示すように、本発明適用前に比べて炉内貯銑滓の増加に伴う減産は大幅に低減し、高炉の安定的な操業を達成することが可能となった。
また、早期に銑滓排出促進のアクションをとることができたため、炉内貯銑滓増加による送風圧力変動は大幅に低下し操業が安定した。
【００３３】
【表１】
これらの効果を享受できたのは、高炉炉体の電位差を連続的に測定監視することにより炉内の貯銑滓状況を常に適切に把握することができたため、早期に促進開口やラップ出銑を実施し銑滓の排出の努め、生産に影響を与える減風などのアクションを極力少なくできた結果であるといえる。
【００３５】
【発明の効果】
本発明によれば、従来間接的にしか推定できなかった高炉炉床部での銑滓貯留レベルを直接的に検知しそれに基づき出銑滓の調整を行うために、炉内銑滓の過剰貯留に伴うトラブルを回避することが可能となる。
【図面の簡単な説明】
【図１】炉床部の縦断面図における接点の配置を示す図
【図２】炉床部の高炉炉体の電位差の推移と出銑滓状況を示す図
【図３】出銑を停止した時間とその間における炉床部の高炉炉体の電位差の増加幅の関係を示す図
【図４】物質収支から推定した炉内残銑量と炉床部の高炉炉体の電位差の増加幅の関係を示す図[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a blast furnace tapping method for avoiding operation troubles associated with an increase in the level of dredged storage at the blast furnace hearth and performing stable operation.
[0002]
[Prior art]
Understanding the level of dredging storage in the hearth of the blast furnace is important for operational management.
If the slag level rises above a predetermined level, the air pressure fluctuation will increase and it will not be possible to maintain a stable operating state.In particular, if the slag level rises to the air blowing tuyere level, the slag will block the tuyere. It becomes impossible to operate.
[0003]
In general, the storage level in the furnace can be roughly estimated from the material balance of soot production and discharge. For example, the amount of soot can be calculated from the amount of charge and its components charged into the blast furnace per unit time, and the amount of soot discharged can be measured by changing the weight of a torpedo car containing pig iron, Since the weight of the water tank manufactured from the slag can be measured by a scale conveyor or the like, the increase amount of the water tank in the furnace can be estimated from the difference between the generated amount and the discharged amount of the water tank.
[0004]
In Japanese Patent Laid-Open No. 7-150210, the output acceleration is calculated using a process computer to determine whether the current output state belongs to the initial, stable, late or end period, and the output end time is predicted. However, this method is also basically a technique that uses the method for estimating the amount of residue in the furnace based on the material balance.
[0005]
On the other hand, as a method for measuring the soot level using a soot detector without using the estimation method of the amount of residue in the furnace based on the mass balance, for example, JP-A-53-86242 discloses a blast furnace. When a plurality of pairs of rod-like graphite electrodes consisting of an anode and a cathode are arranged in the height direction on the hearth part of the furnace wall and electrically connected to each other, the hot metal comes into contact with the pair of rod-like graphite electrodes. A method for measuring the soot level by detecting continuity with a pilot lamp or ammeter is disclosed.
[0006]
Also, in Japanese Patent Application Laid-Open No. 59-140309, at least one pair of electrodes is provided on a brick that forms the furnace wall near the bottom of the blast furnace, and a resistance measurement system (double bridge system) electric circuit is formed by a four-terminal measurement method. And the method of measuring a wrinkle level from the measured value of electrical resistance is disclosed.
[0007]
[Problems to be solved by the invention]
In the method for estimating the amount of residue in the furnace based on the material balance described in JP-A-7-150210, the amount of soot generated is calculated on the assumption that the charged ores are immediately melted. Not only there is a time lag of at least several hours, but also the calculation is performed based on the component analysis values, and therefore errors occur due to the accuracy, representativeness, and variation of the analysis values.
[0008]
In addition, the amount of soot discharged is not directly weighed, such as slag, but is only measured by a scale conveyor etc. after being converted to water, and the error is said to be at least about 10%. ing. For this reason, when estimating the soot level from the material balance, it is indispensable to take a large safety allowance on the assumption of a large error.
[0009]
In addition, the method for measuring the soot level disclosed in Japanese Patent Application Laid-Open No. 53-86242 requires that at least a pair of electrodes be inserted into the furnace so as to be in contact with the soot in order to measure the energization of the soot. For this reason, it is difficult to obtain reliable measurement data of the in-furnace soot level because the energized state fluctuates due to the solidified layer formed by cooling the soot on the electrode surface and the thickness variation.
Further, in this method, since the electrode is installed through the furnace wall at the bottom of the furnace, when the electrode is melted, hot metal flows out from that part, which may cause a serious accident such as damage to the furnace bottom.
[0010]
In addition, the method for measuring the level of fence in JP-A-59-140309 measures the electrical resistance between the brick and the fence, so that the deterioration of the brick over time or the intrusion of the brick into the brick is caused. The measured electrical resistance of brick and fence varies due to fluctuations in conductivity and fluctuations in the conductivity of the fence due to the temperature of the fence near the brick and the solidification or flow state of the fence. It is difficult to obtain the measurement data of the level inside the furnace.
[0011]
Thus, in the conventional technology, there is no method that can measure the storage amount and storage level in the furnace with sufficient accuracy and high reliability, and it is necessary to reduce the wind significantly due to insufficient soot discharge. Operation troubles such as being blocked or the tuyere clogged with slag occurred. For this reason, it has been desired to develop a method capable of continuously and reliably grasping the state of storage in the furnace and taking action more quickly.
[0012]
The present invention measures the storage level at the bottom of the blast furnace continuously and with high reliability, and based on this measurement value, avoids operational troubles associated with the increase in the storage level of the blast furnace and performs stable operation. An object is to provide a method for unloading a blast furnace.
[0013]
[Means for Solving the Problems]
This invention solves said subject and the place made into the summary is as follows.
(1) On the outer wall of the blast furnace body, a plurality of detection contacts are connected to the tuyere level from the bottom plate level of the outer wall iron skin at the bottom of the furnace so that two detection contacts become a detection end for a pair of potential difference measurements. Measure the potential difference between the detection contact and the detection contact at a position higher than the detection contact at the lowermost level , which is mounted at a predetermined distance in the height direction of the When the value exceeds a predetermined set value, one or both of an operation action for decreasing the soot generation rate and an operation action for increasing the soot discharge rate are implemented. .
(2) Among the plurality of detection contacts, at least one attachment position is set to the outlet level or more, and at least one of the other detection contacts is set to be less than the outlet level. The blast furnace tapping method as described in (1).
[0014]
(3) The blast furnace tapping method according to any one of (1) and (2), wherein the tuyere blowing rate is reduced as an operation action for reducing the soot production rate.
(4) As an operation action to increase the dredging discharge speed, either or both of expanding the diameter of the dredging port at the time of dredging or opening a plurality of dredging ports at the same time ( Blast furnace extraction method according to either 1) or (2).
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Details of the present invention will be described below.
The inventors measured the potential of the blast furnace body around the blast furnace hearth, and found that (1) it had a very weak potential distribution in the height direction, and (2) the height direction. It was found that the potential difference of (3) increased or decreased according to the fluctuation of the level of the furnace soot, and (3) the same potential difference was exhibited if the same soot level.
[0016]
Although the details of the cause of the potential difference in the height direction of the blast furnace furnace body are unknown, the inventors believe that the specific gravity of the slag with a lower specific gravity of the upper layer in the soot stored in the furnace and the specific gravity of the lower layer It is inferred that a battery is formed between heavy molten irons, and the potential observed on the furnace wall changes depending on the amount of soot and the fluctuation of the level in the height direction.
[0017]
The present invention has been made on the basis of these findings, attached at least two (plural) detection contacts to the blast furnace body at a predetermined distance in the height direction, and measured the potential difference between the detection contacts, When the measured value of the potential difference exceeds a predetermined set value, one or both of an operation action for decreasing the soot generation speed and an operation action for increasing the soot discharge speed are performed. It is.
[0018]
In addition, it is desirable to measure the potential difference between the detection contacts in which the detection contacts are arranged so that the boundary surface between the slag and the molten iron is sandwiched between the detection contacts. It is desirable that at least one attachment position is at or above the outlet level, and at least one of the other detection contacts is below the outlet level.
[0019]
The present invention relates to a potential difference between a plurality of detection contacts provided at a predetermined interval in the height direction of a blast furnace due to a current that naturally occurs in a firewood in the blast furnace according to an operation state. It is not necessary to forcibly energize by forming an electrical circuit with at least one pair of electrodes as in the prior art, and to directly energize the furnace in the furnace. There is no need to install an electrode through the furnace wall and contact the soot. Therefore, there is no problem that the reliability of the measurement data at the soot level is lowered due to fluctuations in the energized state due to the solidified layer formed by cooling the soot on the electrode surface and the thickness variation thereof as in the prior art.
[0020]
As an example of an embodiment of the present invention, FIG. 1 shows an arrangement of detection contacts for potential difference measurement, and FIG. 2 shows a measurement result of potential difference.
As shown in FIG. 1, a plurality of detection contacts are provided from the bottom level of the outer wall core of the bottom of the blast furnace furnace to the height of the tuyere level so that two detection contacts become a pair of potential difference detection ends. Is installed. The soot level in the furnace can be measured by measuring the potential difference between the sensing contacts where each sensing contact is placed so as to sandwich the interface between the slag and the hot metal. , A detection contact (1) serving as a potential reference is provided in the vicinity of the bottom plate level, and the detection contacts (2) to (5) arranged at positions higher than the detection contact (1) at the bottom are used as a reference. It is preferable to measure the potential difference.
[0021]
FIG. 2 shows a result of measuring the potential difference between the detection contact (1) and each of the detection contacts (2) to (5) over time. In addition, at the time on the horizontal axis in FIG. No. 1 tap mouth and No. 1 2 Shows the tapping time from tapping opening to closing.
As the distance in the height direction from the reference detection contact (1) from FIG. 2 becomes longer, the potential difference between the detection contacts becomes larger, and a potential difference of several hundred μV at the maximum is observed. In addition, over time, the potential difference increases at the beginning of the output when the output diameter is small and the output speed is low, or during the period when output is not performed, and the potential difference decreases at the end of output when the output level decreases. It can be seen that the potential difference changes depending on the storage tank level in the furnace that is linked to the output cycle.
[0022]
In order to clarify the relationship between the level of the storage tank in the furnace and the potential difference, all the outlets were closed and the hot metal discharge was stopped for a certain period of time. As an example of the result, FIG. 3 shows the relationship between the waiting time for the output and the potential difference increase width (the potential difference increase width based on the potential difference when the output port is closed).
It can be seen that the potential difference increase width increases with an increase in the waiting time for the extraction, and that there is a good correlation between the potential difference in the height direction of the blast furnace body and the amount of residue at the bottom of the furnace.
[0023]
Fig. 4 shows the amount of residue in the furnace (calculated value) calculated from the calculation based on the material balance, with the end point of tapping being zero, and the potential difference at the bottom of the furnace based on the potential difference at the end of tapping. It shows the relationship with the increase width.
Although the measured potential difference increase (measured value) and the amount of residual residue in the furnace (calculated value) calculated from the calculation based on the mass balance show a positive correlation, the potential difference increase (measurement) in FIG. Value) and the output waiting time (residual amount in the furnace), the variation of the data is large. This is mainly due to the uncertainty of the residual amount obtained by calculation based on the material balance. It is thought to do.
[0024]
As described above, by continuously measuring the potential difference in the furnace body height direction during blast furnace operation, it is possible to measure the level of the storage tank in the furnace with higher reliability than before, and this potential difference is set to a predetermined value. By managing the operation as described below, it is possible to avoid troubles associated with the rise of the level in the furnace.
[0025]
When the measured value of the potential difference in the furnace body height direction exceeds the preset value during blast furnace operation, the operation action and soot to reduce the soot production rate in order to lower the in-furnace storage soot level. One or both of the operation actions for increasing the discharge speed may be performed.
The soot production rate is the production rate itself of the blast furnace, and can be changed by increasing or decreasing the amount of blown air per unit time. Therefore, as an operation action for reducing the soot generation speed, a method for reducing the tuyere air volume may be used.
[0026]
In addition, as an operation action to increase the dredging discharge speed, the diameter of the spout used at the time of excavation can be expanded by digging with a large cone (promotion opening), In addition, a method of increasing the amount of output per unit time by using other methods such as opening other closed outlets and simultaneously outputting at multiple outlets (lapping) Can do.
[0027]
The preset value of the potential difference for determining whether or not to perform one or both of the operation action for decreasing the soot generation rate and the operation action for increasing the soot discharge rate is determined based on the operation results of the blast furnace. The blast furnace operator may determine in advance based on the relationship with the measured value of the potential difference and the timing of the operation action that allows early recovery without causing operation trouble.
[0028]
Specifically, the potential difference immediately before the blast pressure fluctuation increases due to an increase in the residual amount in the furnace is obtained from past results, and the set value is determined by taking the safety factor into that value or the value. It is determined on the basis of the change over time of the potential difference that has risen after stopping the extraction for a certain period of time.
[0029]
【Example】
As an example of the present invention, using a blast furnace having a furnace internal volume of 3273 m 3 and a hearth diameter of 12.0 m, a one-stage level of bottom carbon brick 5 m below the outlet of the furnace body and 3.8 m from the outlet Detection contacts were installed at the same level as the upper tuyere, the potential difference between these detection contacts was continuously measured, and the operation action was performed based on the measured value of this potential difference.
[0030]
As the operation action, when the measured value of the potential difference reaches the set value: 0.7 mV, the diameter of the tap hole that is being used for taping is expanded by drilling with a large cone (promoting opening), or used for taping Open other blocked outlets and perform an action of simultaneous output (lap output) at multiple outlets, and when the set value reaches 0.75 mV In addition, it was decided to reduce the wind by 10%.
[0031]
The reason for the determination of the above set value: 0.7 mV is that the potential difference immediately before the blast pressure fluctuation increases due to the increase in the residual amount in the actual operation of the blast furnace is examined for one month, and the average potential difference: 0.75 mV, which is the standard Deviation: 0.7 mV from the difference of 0.5 mV.
It should be noted that the potential difference when the wrinkle level is lowered to the spout opening level is about 0.4 mV, and therefore the measured value of the potential difference varies between 0.4 and 0.7 mV.
[0032]
As a result of applying the present invention, as shown in Table 1, the reduction in production accompanying the increase in the in-furnace storage is significantly reduced as compared to before application of the present invention, and stable operation of the blast furnace can be achieved. became.
In addition, since we were able to take action to promote soot discharge at an early stage, fluctuations in blast pressure due to increased storage in the furnace were greatly reduced and operations were stabilized.
[0033]
[Table 1]
We were able to enjoy these effects by continuously measuring and monitoring the potential difference of the blast furnace furnace body so that the storage situation inside the furnace could always be properly grasped. It can be said that this was the result of reducing the actions such as wind reduction that affected the production and efforts to discharge soot.
[0035]
【The invention's effect】
According to the present invention, in order to directly detect the level of dredging storage in the blast furnace hearth, which could only be estimated indirectly, and to adjust the dredging based on that level, excessive storage of dredging in the furnace It is possible to avoid the troubles associated with.
[Brief description of the drawings]
FIG. 1 is a diagram showing the arrangement of contacts in a longitudinal section of the hearth part. FIG. 2 is a diagram showing the transition of the potential difference of the blast furnace body in the hearth part and the output situation. FIG. 3 is stopped. Fig. 4 is a graph showing the relationship between the time and the increase in the potential difference of the blast furnace in the hearth during that period. Fig. 4 Relationship between the amount of residual in the furnace estimated from the material balance and the increase in the potential difference in the blast furnace in the hearth Figure showing
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001225353A JP4184633B2 (en) | 2001-07-26 | 2001-07-26 | Blast furnace extraction method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001225353A JP4184633B2 (en) | 2001-07-26 | 2001-07-26 | Blast furnace extraction method |
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| Publication Number | Publication Date |
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| JP2003034809A JP2003034809A (en) | 2003-02-07 |
| JP4184633B2 true JP4184633B2 (en) | 2008-11-19 |
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| JP2001225353A Expired - Lifetime JP4184633B2 (en) | 2001-07-26 | 2001-07-26 | Blast furnace extraction method |
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