JP4132128B2 - Blast furnace operation method - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は、炉底側壁部レンガ厚みの損耗状態を早期かつ精度良く検知して、レンガ厚みの損耗を抑制する高炉操業法に関するものである。
【０００２】
【従来の技術】
高炉の溶銑原価を低減するためには、種々の変動費を下げると同時に高炉の炉寿命をできるだけ延ばすことが必要である。高炉の炉寿命を律速する部位はシャフト下部と炉底部である。シャフト部については近年補修技術の進歩すなわち休風時におけるステーブ取り替え技術の進歩に伴い、必ずしも炉寿命を律速する要因ではなくなってきている。
【０００３】
一方、炉底部については休風時のレンガ取り替え技術が確立されているとは言えず、炉底部とくに炉底側壁部のレンガ厚みが高炉の炉寿命を律速する要因となっているのが現状である。
したがって、高炉の炉寿命をできるだけ延ばすためには、耐溶銑性、耐溶融スラグ性および冷却効果の観点から、炭素質耐火物で構成されている炉底側壁部のレンガの損耗を抑制する技術と同時に、炉底側壁部のレンガ厚みを早期にかつ精度良く検知し管理する技術が必要である。
【０００４】
炉底側壁部のレンガ厚みを検知する技術としては、炉底側壁部のレンガに挿入した熱電対の先端（通常の挿入深度：50〜100mm）での温度を測定し、該温度測定値からレンガ残存厚みを推定する方法が知られている。
該温度が事前に設定されたレンガ残存厚みの下限値に対応する温度の上限値を越えた場合、あるいは越えると予測される場合に、炉底側壁部レンガ厚み損耗の抑制技術が適用されている。
【０００５】
炉底側壁部のレンガ厚みの損耗を抑制する技術としては、炉底散水量を増加し冷却を強化する方法、TiO2投入量を上昇させ炉底レンガ近傍に存在する溶銑を高粘性化して炉底レンガを保護する方法、損耗箇所の羽口径を縮小あるいは盲にして羽口前に滴下する溶銑滓量を少なくするか、あるいは皆無にする方法、各羽口に設置された熱風弁の開度を調節して、羽口前に滴下する溶銑滓量を少なくする方法が実施されている。とくに、羽口径を縮小あるいは盲にして羽口前に滴下する溶銑滓量を少なくするか、あるいは皆無にする方法は経験的に効果が大きいことが知られている。
【０００６】
例えば、特開昭60-243207号公報には、高炉の円周に炉底温度計ならびに炉底側板温度計を円周の複数箇所に設け、炉底温度ならびに炉底側板温度を測温し、炉底温度、側板温度のいずれかが設定値以上に上昇した場合に、上昇した温度計上部の羽口送風量を、送風支管に設置した熱風制御弁により制御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】
しかし、上記に示した炉底側壁部のレンガ温度から炉底側壁部のレンガ厚みの損耗状態を検知する方法では、以下に示す問題点がある。
炉底側壁部に挿入した熱電対先端でのレンガ温度は、炉内の熱状態だけでなく、冷却条件（例：季節による冷却水温度差）、スタンプ材の劣化状態によるスタンプ材熱物性値の変化等の影響を受けやすい。
【０００８】
例えば、炉底側壁部に挿入した熱電対先端でのレンガ温度は、夏場と冬場での冷却水温度の差により変化する。とくに、スタンプ材の劣化状態によりスタンプ材の熱物性値が大きく変化している高炉では、熱電対先端でのレンガ温度値からレンガ残存厚み、またはレンガと粘稠層合計の残存厚みを推定する際の誤差が大きくなる。上記の方法では、レンガ残存厚みの誤差に起因する制御手段実施時期の間違いや遅れにより、高炉の炉寿命を短くしてしまう可能性もある。
【０００９】
本発明は、このような従来の炉底側壁部のレンガに挿入した熱電対先端の温度指示値による炉底側壁部のレンガ厚みの誤差に起因する検知の時間遅れの問題点に鑑み、炉底側壁部のレンガ温度指示値による検知方法とは異なる方法を用いて、炉底側壁部のレンガの損耗状態を早期かつ精度良く検知することにより、上記問題点を解決することを目的としている。
【００１０】
【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ために、下記手段を講じるものである。
（１）高炉炉底中心位置での炉内から炉外方向への熱流束を測定するとともに、高炉炉底側壁のレンガと粘稠層合計の残存厚みを複数個所で測定し、前記熱流束が基準値以下に下降した場合に、前記炉底側壁部のレンガと粘稠層合計の残存厚みが、過去に基準値以下となった箇所の上部の羽口の送風量を支管風量制御弁によって低下し、前記熱流束が基準値超に上昇した場合に、支管風量制御弁によって各羽口の送風量を同じ値になるように戻すことを特徴とする。
（２）高炉炉底中心位置での炉内から炉外方向への熱流束を測定するとともに、高炉炉底側壁のレンガと粘稠層合計の残存厚みを複数個所で測定し、前記熱流束が基準値以下に下降した場合に、前記炉底側壁部のレンガと粘稠層合計の残存厚みが、相対的に薄くなっている箇所、または、該残存厚みの減少速度が大きい箇所の上部の羽口の送風量を支管風量制御弁によって低下し、前記熱流束が基準値超に上昇した場合に、支管風量制御弁によって各羽口の送風量を同じ値になるように戻すことを特徴とする。
【００１５】
【発明の実施の形態】
従来の炉底側壁部のレンガに挿入した熱電対先端のレンガ温度を検知し、該温度が下限レンガ残存厚みに対応する温度上限値を越えた場合に、炉底側壁部のレンガ損耗が進行していると判断する方法に対して、本発明法は、炉底側壁部のレンガ損耗状態を早期かつ精度良く検知して、炉底側壁部レンガの損耗前あるいはレンガ損耗の初期段階で炉底側壁部のレンガ損耗を抑制するものである。
炉底側壁部のレンガ損耗状態を早期かつ精度良く検知する方法にはいくつかの方法がある。
【００１６】
一番目の方法は、高炉の炉底側壁部の炉内から炉外への熱流束を測定または計算する方法である。熱流束とは単位面積あたり単位時間あたりの熱の移動量(kW/m2)であり、下記(1)式で定義される。
Ｑ ＝ ΔＴ×λ／Ｌ ・・・・（１）
ここで、Ｑは熱流束(kW/m2)
ΔＴは２点間の温度差(℃)
λは２点間の物質の熱伝導率(kW/(m・K))
Ｌは２点間の距離(m)
である。
【００１７】
一次元定常伝熱解析により、夏場と冬場の冷却水温度の差異による熱電対先端のレンガ温度の変化と同じ位置での熱流束の変化、および、スタンプ材の劣化前後における熱電対先端のレンガ温度の変化と同じ位置での熱流束の変化を比較する。基礎式を下記(2)式に示す。
d2 Ｔ／dｘ2 ＝ ０ ・・・・（２）
ここで、Ｔは温度(℃)
ｘは位置（ｍ）
である。
【００１８】
図１に計算例における境界条件を示す。鉄皮、スタンプ材、レンガ、粘稠層の厚みをそれぞれ60mm,100mm,700mm,100mmと仮定し、熱電対のレンガ挿入位置をレンガ外表面から150mmの位置と仮定した。なお、鉄皮、スタンプ材、レンガ、粘稠層の熱伝導率については、それぞれ6、16、29、52(W/(m ・K))と仮定した。
粘稠層の炉内側温度は1150℃と仮定し、冷却水温度は30℃、35℃、25℃と仮定して計算した。スタンプ材の劣化の影響については、スタンプ材と鉄皮の間の1mmの間隙が生じたと仮定して計算した。
【００１９】
【表１】
表１に一次元定常伝熱解析結果を示す。表から明らかなように、夏場（35℃）と冬場（25℃）の冷却水温度差によるレンガ温度Ｔ2の相対変化の絶対値は、2.4％(=｜(297-290)/290×100｜)、熱流束の相対変化の絶対値は、0.9％(=｜(16.71-16.86)/16.86×100｜)と、熱流束の相対変化の絶対値はレンガ温度の相対変化の絶対値に比べて小さく、熱流束でレンガ損耗状態を検知・管理するほうが誤差が小さい。
【００２１】
さらに、スタンプ材と鉄皮の間に1mmの間隙が生じた場合のレンガ温度の相対変化の絶対値は、90.1％(=｜(557-293)/293×100｜)、熱流束の相対変化は、30.8％(=｜(11.62-16.78)/16.78×100｜)と、熱流束の相対変化はレンガ温度の相対変化に比べて圧倒的に小さく、熱流束でレンガ損耗状態を検知・管理するほうが誤差が小さい。
【００２２】
さらに最も重要なことは、熱流束で判断する場合には、粘稠層の成長かスタンプ材の劣化の影響と容易に推定できるため、間違って炉底側壁部のレンガ損耗の抑制対策を実施することがないことである。しかし、温度で判断する場合には、炉内側の影響すなわちレンガ損耗の影響かスタンプ材劣化の影響かを容易に判断することはできず、炉底側壁部レンガの保護という安全サイドの立場から、過剰なレンガ損耗抑制対策（例えば燃料比上昇、臨時休風、減風、羽口の盲化、ほか）を実施する可能性があり、その場合には大幅な減産や操業変動を招く可能性がある。
【００２３】
次に、一次元非定常伝熱解析により、炉内のステップ応答的変化に対する熱流束と温度の時間変化を比較する。基礎式を下記(3)式に示す。
∂Ｔ／∂ｔ ＝ α・∂2 Ｔ／∂ｘ2 ・・・・（３）
ここで、Ｔは温度(℃)
ｘは位置（ｍ）
ｔは時間（ｈ）
αは温度伝導率（ｍ2 ／ｈ）
である。
本計算時には、ある時点で粘稠層が剥離して、レンガ表面が1150℃になったと仮定し、その時点からの炉底側壁部の熱流束と温度の変化を計算した。
【００２４】
図２に示すように、熱流束の時間微分値は温度の時間微分値に比べ、約１時間早い時期から急激に上昇している。したがって熱流束で判断する場合には、前述したレンガ厚みの損耗状態の推定精度の良さに加えて、温度に比べて早期にレンガ厚みの損耗状態を検知できることがわかる。
なお、熱流束を測定する手段としては、熱流束計により測定する方法、炉底側壁のレンガ内の半径方向に挿入した深度の異なる熱電対先端の温度から計算する方法等がある。熱流束計については、鉄皮だけでなく、レンガ外表面あるいはレンガ内に埋め込むことも可能である。
【００２５】
熱流束が基準値以上に上昇した場合には、熱流束が基準値以上に上昇した箇所の円周方向の角度で少なくとも±３０゜以内に位置する羽口の内、一本または複数本の羽口の送風量を相対的に低下させる。その方法としては、前記箇所の羽口の支管風量制御弁の開度を小さくするか、または前記箇所以外の羽口の支管風量制御弁の開度を大きくするか、何れかの処置をとることによって送風量を調整する。
上記方法により、熱流束が基準値未満になった場合には、支管風量制御弁により各羽口の送風量をほぼ同じ値となるように調節して通常操業に戻す。
【００２６】
二番目の方法は、高炉炉底側壁のレンガと粘稠層合計の残存厚みを測定または計算する方法である。粘稠層とは炉内側の凝固層のことであり、伝熱計算上では1100℃〜1200℃の炉内温度より決定される。
なお、残存厚みを測定する手段としては、弾性波により測定する方法、炉底側壁のレンガ内の半径方向に挿入した深度の異なる熱電対先端の温度差から計算する方法がある。
【００２７】
残存厚みが基準値以下に低下する場合には、残存厚みが基準値以下に低下した箇所の円周方向の角度で±３０゜以内に位置する羽口の内、一本または複数本の羽口の送風量を相対的に低下させる。その方法としては、前記箇所の羽口の支管風量制御弁の開度を小さくするか、または前記箇所以外の羽口の支管風量制御弁の開度を大きくするか、何れかの処置をとることによって送風量を調整する。
上記方法により、残存厚みが基準値超に上昇した場合には、支管風量制御弁により各羽口の送風量がほぼ同じ値となるように調整して通常操業に戻す。
【００２８】
三番目の方法は、高炉炉底中心位置での炉内から炉外方向への熱流束を測定または計算する方法である。この方法では、高炉炉底中心の炉内から炉外方向への熱流束が低位レベルで推移した後には炉底側壁部のレンガ温度が上昇するという従来の知見に基づき、高炉炉底中心位置の炉内から炉外方向への熱流束から１〜３ヶ月後の炉底側壁のレンガ損耗状態を事前に予測する。
なお、熱流束を測定する手段としては、レンガ外表面あるいはレンガ内に埋め込んだ熱流束計により測定する方法、炉底中心のレンガ内の深さ方向に挿入した深度の異なる熱電対先端の温度差から計算する方法がある。
【００２９】
熱流束が基準値以下に下降する場合には、炉底側壁部のレンガと粘稠層合計の残存厚みが過去に基準値以下となった箇所、または、炉底側壁部のレンガの残存厚みまたはレンガと粘稠層合計の残存厚みが相対的に薄くなっている箇所、または、残存厚みの減少速度が大きい箇所、これらの何れかの箇所の上部の羽口の送風量を低下させる。その方法としては、前記箇所の羽口の支管風量制御弁の開度を小さくするか、または前記箇所以外の羽口の支管風量制御弁の開度を大きくするか、何れかの処置をとることによって送風量を調整する。
上記方法により、炉底中心位置での炉内から炉外への熱流束が基準値超に上昇した場合には、支管風量制御弁により各羽口の送風量がほぼ同じ値となるように調整して通常操業に戻す。
【００３０】
【実施例】
以下、図面に示す実施例に基づいて具体的に説明する。
（参考例１）内容積が３０００ｍ３級で羽口数が２９本の中型高炉において、高炉炉底側壁部における炉内から炉外方向への熱流束を６箇所で測定し、ある箇所の熱流束の時間微分値が急上昇すると同時に熱流束が上昇し基準値の１３００Ｗ／ｍ２以上になった。そこで、炉底側壁部のレンガ損耗が進行すると予測し、熱流束が基準値以上に上昇した箇所の円周方向の角度で±３０゜以内に位置する羽口の送風量を、送風支管に設置した支管風量制御弁により制御を開始した。
【００３１】
図３に示すように、熱流束が基準値以上に上昇した箇所の円周方向の角度で±３０゜以内に位置する５箇所の羽口の送風量を、全周の支管風量制御弁の調整により、送風量を羽口数で除した平均羽口送風量を100%とした相対羽口送風量で70%以下になるように制御した。
なお、円周方向の角度で±３０゜以内に位置する羽口数は高炉の全羽口数（高炉の内容積によって異なる）の内、本高炉の場合には５箇所であった。
【００３２】
このアクションを１週間続けた後に高炉炉底側壁の熱流束が低下し始め、10日後には基準値以下になった。さらに５日経過した後に、上昇箇所上部の５箇所の羽口の相対羽口送風量を80%になるように支管風量制御弁により制御し、さらに５日経過した後に、上昇箇所上部の５箇所の羽口の相対羽口送風量を90%になるように支管風量制御弁により制御し、さらに10日経過した後に、上昇箇所上部の５箇所の羽口の相対羽口送風量を100%に戻した。結果的には、炉底側壁部の熱流束が上昇し基準値以上になった時点から30日後には、炉底側壁部の熱流束が沈静化しほぼ元のレベルに戻った。
【００３３】
図４には従来法、すなわち、炉底側壁部のレンガに挿入した熱電対の先端位置（通常の挿入深度：50〜100mm）でのレンガ温度を測定し、その温度測定値が事前に設定された上限値に近づいた場合、あるいは上限値を越えた場合に、上述した炉底側壁部レンガの損耗を抑制する対策を実施した場合を示したが、温度測定値の精度上の問題および感度上の問題から、レンガ損耗の抑制対策の実施が、参考法を実施した場合に比べて、数時間から時には１日も遅れることがある。このレンガ損耗の抑制対策の実施の遅れは、炉底側壁部のレンガ損耗の進行に致命的な影響を及ぼす可能性がある。
【００３４】
（参考例２）内容積が４０００ｍ３級で羽口数が３５本の火入れ以降１１年を経過した大型高炉において、高炉炉底側壁の粘稠層を含んだ残存厚みを４箇所で測定し、ある箇所の残存厚みが基準値の７００ｍｍ以下になった。そこで、炉底側壁部のレンガ損耗が進行すると予測し、残存厚みが基準値以下に低下した箇所の円周方向の角度で±３０゜以内に位置する羽口の送風量を、送風支管に設置した支管風量制御弁により制御を開始した。
【００３５】
図５に示すように、円周方向の角度で±３０゜以内に位置する６箇所の羽口の送風量を、送風量を羽口数で除した平均羽口送風量を100%とした相対羽口送風量で70%以下になるように支管風量制御弁により制御した。
なお、残存厚みが基準値以下に低下した箇所の円周方向の角度で±３０゜以内に位置する羽口数は高炉の全羽口数（高炉の内容積によって異なる）の内、本高炉の場合には６箇所であった。
【００３６】
このアクションを１週間続けた後に該残存厚み低下箇所の残存厚みが上昇し始め、10日後には基準値以上になった。さらに５日経過した後に、該残存厚み低下箇所上部の６箇所の羽口の相対羽口送風量を80%になるように支管風量制御弁により制御し、さらに５日経過した後に、該残存厚み低下箇所の６箇所の羽口の相対羽口送風量を90%になるように支管風量制御弁により制御し、さらに10日経過した後に、該残存厚み低下箇所上部の６箇所の羽口の相対羽口送風量を100%に戻した。結果的には、高炉炉底側壁の粘稠層を含んだ残存厚みが低下し基準値以下になった時点から30日後には、高側壁部の粘稠層を含んだ残存厚みがほぼ元のレベルに戻った。
【００３７】
（実施例３）
内容積が5000m3級で羽口数が38本の大型高炉において、高炉炉底中心位置での炉内から炉外方向への熱流束を１箇所で測定し、該熱流束が基準値の700W/m2 以下になった。
その時点から１ヶ月後には高炉炉底に粘稠層が発達して、炉底部での溶融体の流れが環状流に向かう危険があると判断した。
炉底部での溶融体の流れが環状流に向かえば、炉底側壁部のレンガ損耗が進行すると予測し、炉底側壁の粘稠層を含んだ残存厚みが過去に基準値以下になった箇所の上部の３箇所の羽口の送風量を、送風支管に設置した支管風量制御弁により調整した。
【００３８】
具体的には、図６に示すように、送風量を羽口数で除した平均羽口送風量を100%とした相対羽口送風量で70%以下になるように支管風量制御弁により調整した。このアクションを実施した時点から20日経過後にまず炉底中心の熱流束が上昇し始め、さらに10日後には基準値以上になった。そして、その時点で一旦上昇し始めた炉底側壁部の熱流束も低下し始めた。
【００３９】
さらに10日経過した後に、粘稠層を含んだ残存厚みが過去に基準値以下になった箇所の上部の２ないし３箇所の上部の羽口の相対羽口送風量を80%になるように支管風量制御弁により調整し、さらに10日経過した後に、粘稠層を含んだ残存厚みが過去に基準値以下になった箇所の上部の２ないし３箇所の上部の羽口の相対羽口送風量を100%に戻した。結果的には、炉底中心の炉内から炉外方向への熱流束が低下し基準値以下になった時点から50日後には、炉底中心の炉内から炉外方向への熱流束が上昇しほぼ元のレベルに戻った。
【００４０】
本発明法を実施した場合と、従来法、すなわち、炉底側壁部のレンガに挿入した熱電対の先端位置（通常の挿入深度：50〜100mm）でのレンガ温度を測定し、その温度測定値が事前に設定された上限値に近づいた場合、あるいは上限値を越えた場合に、上述した炉底側壁部レンガの損耗を抑制する対策を実施した場合の炉底側壁部のレンガ温度の変化を図７に示した。
【００４１】
本発明法実施の場合には、従来法実施時に比べて、炉底側壁部のレンガ損耗状況を早期に予測しているため、対策の実施時期が早くなっている。そのため、炉底側壁部のレンガ温度の上昇レベルが小さく、しかも対策実施後の炉底側壁部のレンガ温度の元のレベルへの低下時間も、従来法実施時に比べて、短くなっている。
【００４２】
（実施例４）
内容積が5000m3級で羽口数が38本の大型高炉において、高炉炉底中心位置での炉内から炉外方向への熱流束を１箇所で測定し、該熱流束が基準値の700W/m2 以下になった。
そこでその時点から１ヶ月後には、高炉炉底に粘稠層が発達して、炉底部での溶融体の流れが環状流に向かう危険があると判断した。
炉底部での溶融体の流れが環状流に向かえば、炉底側壁部のレンガ侵食が進行すると予測し、炉底側壁の粘稠層を含んだ残存厚みが現時点で相対的に薄くなっている箇所で、最小および２番目、３番目に小さい箇所の上部の羽口の送風量を、送風支管に設置した支管風量制御弁により調整した。
【００４３】
図８に示すように、送風量を羽口数で除した平均羽口送風量を100%とした相対羽口送風量で70%以下になるように支管風量制御弁により調整した。このアクションを実施した20日経過後には、まず炉底中心の熱流束が上昇し始め、さらに10日後には基準値以上になった。そしてその時点で、一旦上昇し始めた炉底側壁部の熱流束も低下し始めた。
【００４４】
さらに10日経過した後に、粘稠層を含んだ残存厚みが現時点で相対的に薄くなっている箇所で、最小および２番目、３番目に小さい箇所の上部の相対羽口送風量を80%になるように支管風量制御弁により制御し、さらに10日経過した後に、上記した箇所すなわち、残存厚みが最小および２番目、３番目に小さい箇所の上部の相対羽口送風量を100%に戻した。結果的には、炉底中心の炉内から炉外方向への熱流束が低下し基準値以下になった時点から50日後には、炉底中心の炉内から炉外方向への熱流束が上昇しほぼ元のレベルに戻った。
【００４５】
本発明法を実施した場合と、従来法、すなわち、炉底側壁部のレンガに挿入した熱電対の先端位置（通常の挿入深度：50〜100mm）でのレンガ温度を測定し、その温度測定値が事前に設定された上限値に近づいた場合、あるいは上限値を越えた場合に、上述した炉底側壁部レンガの損耗を抑制する対策を実施した場合の炉底側壁部のレンガ温度の変化を図９に示した。
【００４６】
本発明法実施の場合には、従来法実施時に比べて、炉底側壁部のレンガ損耗状況を早期に予測しているため、対策の実施時期が早くなっている。そのため、炉底側壁部のレンガ温度の上昇レベルが小さく、しかも対策実施後の炉底側壁部のレンガ温度の元のレベルへの低下時間も、従来法実施時に比べて、短くなっている。
【００４７】
【発明の効果】
レンガ温度指示値による炉底側壁部のレンガ残存厚みを検知する従来の方法とは異なる本発明法を用いて、炉底側壁部のレンガの損耗状態を早期かつ精度良く検知し、レンガ損耗度が大きいまたはレンガ損耗速度が大きい羽口または複数本の羽口の支管風量制御弁を調節することにより、レンガ温度を検知して対策を実施している従来の方法に比べて、炉底側壁部のレンガ損耗が進行してレンガ温度が大幅に上昇する事態を防止できるようになった。
その結果、炉底側壁部のレンガ損耗の抑制対策による長期間にわたる大幅な減産や溶銑コストの上昇をもたらす事態を回避できるようになった。
【図面の簡単な説明】
【図１】 伝熱計算時の境界条件を示す図
【図２】 一次元非定常伝熱解析による炉内のステップ応答的変化に対する熱流束と温度の時間微分値の比較を示す図
【図３】 参考法実施前後のある箇所の炉底側壁部の炉内から炉外方向への熱流束の推移とアクションを実施した羽口の相対羽口送風量の推移を示す図
【図４】 参考法実施時と従来法実施時のレンガ損耗抑制対策実施時期の比較を示す図
【図５】 参考法実施前後のある箇所の炉底側壁部の粘稠層を含んだ残存厚みの推移とアクションを実施した羽口の相対羽口送風量の推移を示す図
【図６】 本発明法実施前後の炉底中心の炉内から炉外方向への熱流束の推移と粘稠層を含んだ残存厚みが過去に基準値以下になった箇所の上部の羽口の相対羽口送風量の推移を示す図
【図７】 本発明法実施時と従来法実施時のレンガ損耗抑制対策実施時期の比較を示す図
【図８】 本発明法実施前後の炉底中心の炉内から炉外方向への熱流束の推移と粘稠層を含んだ残存厚みが現時点で最小になった箇所の上部の２箇所の羽口の相対羽口送風量の推移を示す図
【図９】 本発明法実施時と従来法実施時のレンガ損耗抑制対策実施時期の比較を示す図
【符号の説明】
１．粘稠層
２．レンガ
３．スタンプ材
４．鉄皮
５．熱電対の挿入位置
６．炉内（溶銑、溶滓）
７．散水部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a blast furnace operation method that detects a worn state of a brick thickness at the bottom of a furnace bottom in an early and accurate manner and suppresses the worn thickness of the brick.
[0002]
[Prior art]
In order to reduce the hot metal cost of the blast furnace, it is necessary to reduce the various variable costs and at the same time extend the furnace life of the blast furnace as much as possible. The parts that control the furnace life of the blast furnace are the lower part of the shaft and the bottom part of the furnace. In recent years, with the progress of repair technology, that is, the progress of stave replacement technology during resting wind, the shaft portion has not necessarily become a factor limiting the life of the furnace.
[0003]
On the other hand, it cannot be said that the brick replacement technology at rest is established for the bottom of the furnace, and the thickness of the brick at the bottom of the furnace, especially the side wall of the furnace bottom, is the factor that determines the life of the blast furnace. is there.
Therefore, in order to extend the furnace life of the blast furnace as much as possible, from the viewpoint of hot metal resistance, resistance to molten slag and cooling effect, a technique for suppressing the wear of bricks on the bottom wall of the furnace bottom made of carbonaceous refractories At the same time, it is necessary to have a technique for detecting and managing the brick thickness on the bottom wall of the furnace at an early stage and with high accuracy.
[0004]
The technology to detect the thickness of the brick at the bottom wall of the furnace is to measure the temperature at the tip of the thermocouple inserted into the brick at the bottom wall of the furnace (normal insertion depth: 50 to 100 mm), A method for estimating the remaining thickness is known.
When the temperature exceeds or is predicted to exceed the upper limit value of the temperature corresponding to the preset lower limit value of the remaining brick thickness, the technique for suppressing the furnace bottom side wall brick thickness wear is applied. .
[0005]
The technique for suppressing wear of the furnace bottom side wall of the brick thickness, a method of enhancing the increased cooling the furnace bottom watering amount, the molten iron that is present in the vicinity allowed hearth bricks increasing the TiO 2 input amount and high viscosity of the furnace A method to protect the bottom brick, a method to reduce or blind the diameter of the tuyere at the point of wear and to reduce or eliminate the amount of hot metal dripping before the tuyere, the opening of the hot air valve installed at each tuyere The method of reducing the amount of hot metal dripped in front of a tuyere is adjusted. In particular, it has been empirically known that the method of reducing or blinding the tuyere diameter to reduce the amount of hot metal dripped in front of the tuyere, or making it completely absent has a great effect.
[0006]
For example, in JP-A-60-243207, a furnace bottom thermometer and a furnace bottom side plate thermometer are provided at a plurality of locations around the circumference of the blast furnace, and the furnace bottom temperature and the furnace bottom side plate temperature are measured, A method is disclosed in which when either the furnace bottom temperature or the side plate temperature rises to a set value or more, the tuyere blast volume of the elevated temperature indicator is controlled by a hot air control valve installed in the blast branch pipe.
[0007]
[Problems to be solved by the invention]
However, the method for detecting the worn state of the brick thickness of the furnace bottom side wall portion from the brick temperature of the furnace bottom side wall portion described above has the following problems.
The brick temperature at the tip of the thermocouple inserted in the bottom wall of the furnace is not only the heat state in the furnace, but also the cooling conditions (eg, the temperature difference of the cooling water depending on the season) and the thermal properties of the stamp material due to the deterioration of the stamp material. Susceptible to changes.
[0008]
For example, the brick temperature at the tip of the thermocouple inserted in the bottom wall of the furnace varies depending on the difference in cooling water temperature between summer and winter. In particular, in a blast furnace where the thermophysical value of the stamp material varies greatly due to the deterioration of the stamp material, when estimating the remaining brick thickness or the total remaining brick and viscous layer thickness from the brick temperature value at the thermocouple tip The error becomes larger. In the above-described method, there is a possibility that the furnace life of the blast furnace may be shortened due to an error or delay in the control means implementation time due to the error in the remaining brick thickness.
[0009]
In view of the problem of the detection time delay caused by the error in the brick thickness of the bottom wall of the furnace bottom due to the temperature indication value of the thermocouple tip inserted in the brick of the conventional bottom wall of the furnace bottom, An object of the present invention is to solve the above-mentioned problems by detecting the worn state of bricks on the side wall of the furnace bottom early and accurately using a method different from the detection method based on the brick temperature indication value of the side wall.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention takes the following measures.
(1) Measure the heat flux from the inside of the furnace to the outside of the furnace at the center position of the blast furnace bottom, and measure the total remaining thickness of the brick and the viscous layer on the bottom wall of the blast furnace bottom at a plurality of locations. When falling below the reference value, the residual thickness of the brick and viscous layer on the bottom wall of the furnace bottom is reduced by the branch airflow control valve at the upper tuyere at the location where the residual thickness was previously below the reference value. and, when the heat flux is increased to the reference value exceeds, and returning such that the air blowing amount of the tuyere to the same value by the branch pipe air amount control valve.
(2) Measure the heat flux from the inside of the furnace to the outside of the furnace at the center position of the blast furnace bottom, and measure the total remaining thickness of the bricks and the viscous layer on the bottom wall of the blast furnace bottom at a plurality of locations. When falling below the reference value, the remaining thickness of the brick and the viscous layer on the side wall of the furnace bottom is relatively thin, or the upper wing of the portion where the decrease rate of the residual thickness is large the blowing amount of the mouth decreases by branch pipe air amount control valve, when the heat flux is increased to the reference value greater than said the returning so that the air blowing amount of the tuyere to the same value by the branch pipe air amount control valve To do.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
When the brick temperature at the tip of the thermocouple inserted in the brick at the bottom wall of the conventional furnace bottom is detected and the temperature exceeds the upper temperature limit corresponding to the remaining thickness of the lower brick, the brick wear at the bottom wall of the furnace proceeds. The method according to the present invention detects the brick wear state of the bottom wall of the furnace bottom early and with high accuracy, and the bottom wall of the furnace bottom before or at the initial stage of the brick wear. The brick wear of the part is suppressed.
There are several methods for quickly and accurately detecting the brick wear state of the bottom wall of the furnace bottom.
[0016]
The first method is a method of measuring or calculating the heat flux from the inside of the furnace bottom wall of the blast furnace to the outside of the furnace. The heat flux is the amount of heat transferred per unit time (kW / m 2 ) per unit area and is defined by the following equation (1).
Q = ΔT × λ / L (1)
Where Q is the heat flux (kW / m 2 )
ΔT is the temperature difference between two points (° C)
λ is the thermal conductivity of the material between two points (kW / (m · K))
L is the distance between two points (m)
It is.
[0017]
By one-dimensional steady heat transfer analysis, the heat flux change at the same position as the thermocouple brick temperature change due to the difference in the cooling water temperature in summer and winter, and the brick temperature at the thermocouple tip before and after deterioration of the stamp material Compare the change in heat flux at the same position as the change in. The basic formula is shown in the following formula (2).
d 2 T / dx 2 = 0 (2)
Where T is the temperature (° C)
x is position (m)
It is.
[0018]
FIG. 1 shows boundary conditions in the calculation example. The thickness of the iron skin, stamp material, brick, and viscous layer was assumed to be 60 mm, 100 mm, 700 mm, and 100 mm, respectively, and the thermocouple brick insertion position was assumed to be 150 mm from the brick outer surface. The thermal conductivity of the iron skin, stamp material, brick, and viscous layer was assumed to be 6, 16, 29, and 52 (W / (m · K)), respectively.
The temperature inside the viscous layer was assumed to be 1150 ° C, and the cooling water temperature was assumed to be 30 ° C, 35 ° C, and 25 ° C. The effect of the deterioration of the stamp material was calculated on the assumption that a 1 mm gap was created between the stamp material and the iron skin.
[0019]
[Table 1]
Table 1 shows the results of one-dimensional steady heat transfer analysis. As is clear from the table, the absolute value of the relative change in brick temperature T 2 due to the difference in cooling water temperature between summer (35 ° C) and winter (25 ° C) is 2.4% (= | (297-290) / 290 × 100 The absolute value of the relative change in heat flux is 0.9% (= | (16.71-16.86) /16.86×100 |), and the absolute value of the relative change in heat flux is compared to the absolute value of the relative change in brick temperature. The error is smaller when detecting and managing brick wear with heat flux.
[0021]
Furthermore, the absolute value of the relative change in brick temperature when a gap of 1 mm occurs between the stamp material and the iron skin is 90.1% (= | (557-293) / 293 × 100 |), the relative change in heat flux Is 30.8% (= | (11.62-16.78) /16.78×100 |), the relative change in heat flux is overwhelmingly smaller than the relative change in brick temperature, and brick wear is detected and managed by heat flux. The error is smaller.
[0022]
Most importantly, when judging by heat flux, it can be easily estimated that the growth of the viscous layer or the deterioration of the stamp material, so wrongly take measures to suppress brick wear on the bottom wall of the furnace. There is nothing to do. However, when judging by temperature, it is not possible to easily determine the effect of the inside of the furnace, that is, the effect of brick wear or the deterioration of the stamp material, from the safety side standpoint of protecting the bottom wall brick of the furnace, There is a possibility of implementing excessive brick wear prevention measures (for example, fuel ratio increase, temporary wind suspension, wind reduction, blinding of tuyere, etc.), which may lead to significant production cuts and operational fluctuations. is there.
[0023]
Next, the time change of heat flux and temperature with respect to the step response change in the furnace is compared by one-dimensional unsteady heat transfer analysis. The basic formula is shown in the following formula (3).
∂T / ∂t = α · ∂ 2 T / ∂x 2 (3)
Where T is the temperature (° C)
x is position (m)
t is time (h)
α is the temperature conductivity (m 2 / h)
It is.
At the time of this calculation, it was assumed that the viscous layer peeled off at a certain point and the brick surface reached 1150 ° C, and the change in the heat flux and temperature at the bottom wall of the furnace from that point was calculated.
[0024]
As shown in FIG. 2, the time differential value of the heat flux rapidly increases from the time about 1 hour earlier than the time differential value of the temperature. Therefore, when judging by heat flux, in addition to the good estimation accuracy of the wear state of the brick thickness described above, it can be seen that the wear state of the brick thickness can be detected earlier than the temperature.
As a means for measuring the heat flux, there are a method of measuring with a heat flux meter, a method of calculating from the temperature of the tip of a thermocouple with a different depth inserted in the brick on the bottom wall of the furnace bottom. About a heat flux meter, it is also possible to embed not only in an iron skin but also in the brick outer surface or in a brick.
[0025]
If the heat flux rises above the reference value, one or more feathers in the tuyere located at least ± 30 ° in the circumferential angle of the location where the heat flux rises above the reference value The amount of air blown from the mouth is relatively reduced. As the method, the opening of the branch air volume control valve at the tuyere at the location is reduced, or the opening of the tuyere air volume control valve at the tuyere other than the location is increased. To adjust the air flow.
When the heat flux becomes less than the reference value by the above method, the air flow rate of each tuyere is adjusted to be almost the same value by the branch air volume control valve and returned to the normal operation.
[0026]
The second method is a method of measuring or calculating the remaining thickness of the total brick and viscous layer on the bottom wall of the blast furnace furnace. The viscous layer is a solidified layer inside the furnace, and is determined from the furnace temperature of 1100 ° C. to 1200 ° C. in heat transfer calculation.
As a means for measuring the remaining thickness, there are a method of measuring by an elastic wave and a method of calculating from a temperature difference at the tip of a thermocouple having different depths inserted in the radial direction in the brick of the furnace bottom side wall.
[0027]
If the remaining thickness falls below the reference value, one or more tuyere among the tuyere located within ± 30 ° in the circumferential direction of the location where the remaining thickness falls below the reference value The air flow rate is relatively reduced. As the method, the opening of the branch air volume control valve at the tuyere at the location is reduced, or the opening of the tuyere air volume control valve at the tuyere other than the location is increased. To adjust the air flow.
When the remaining thickness rises above the reference value by the above method, the branch air volume control valve adjusts the air volume of each tuyere to be substantially the same value and returns to normal operation.
[0028]
The third method is to measure or calculate the heat flux from the inside of the furnace to the outside of the furnace at the center position of the blast furnace bottom. In this method, based on the conventional knowledge that the brick temperature at the bottom wall of the furnace bottom rises after the heat flux from the inside of the furnace at the center of the blast furnace to the outside of the furnace changes at a low level, Predict the brick wear state of the bottom wall of the furnace bottom after 1-3 months from the heat flux from the inside of the furnace to the outside of the furnace.
As a means of measuring the heat flux, there is a method of measuring with a heat flux meter embedded in the brick outer surface or in the brick, the temperature difference between the tips of thermocouples with different depths inserted in the depth direction in the brick at the center of the furnace bottom. There is a method to calculate from.
[0029]
When the heat flux falls below the reference value, the remaining thickness of the brick and the viscous layer in the bottom wall of the furnace bottom is the reference value in the past, or the remaining thickness of the brick on the bottom wall of the furnace or The location where the residual thickness of the brick and the viscous layer is relatively thin, or the location where the rate of decrease in the residual thickness is large, reduces the air flow rate at the upper tuyere of any of these locations. As the method, the opening of the branch air volume control valve at the tuyere at the location is reduced, or the opening of the tuyere air volume control valve at the tuyere other than the location is increased. To adjust the air flow.
By the above method, when the heat flux from the inside of the furnace to the outside of the furnace at the center position of the furnace rises above the reference value, the branch air volume control valve is adjusted so that the air flow rate at each tuyere becomes almost the same value. Then return to normal operation.
[0030]
【Example】
Hereinafter, a specific description will be given based on an embodiment shown in the drawings.
( Reference Example 1) In a medium-sized blast furnace with an inner volume of 3000 m 3 grade and 29 tuyere, the heat flux from the inside of the furnace to the outside of the furnace at the bottom wall of the blast furnace was measured at 6 locations, and the heat flux at a certain location At the same time, the time differential value increased rapidly and the heat flux increased to a reference value of 1300 W / m 2 or more. Therefore, it is predicted that brick wear on the bottom wall of the furnace will progress, and the air volume of the tuyere located within ± 30 ° in the circumferential angle where the heat flux rises above the reference value is installed in the air supply branch Control was started by the branch pipe air flow control valve.
[0031]
As shown in Fig. 3, the air flow rate at the five tuyere located within ± 30 ° in the circumferential angle at the location where the heat flux rises above the reference value is adjusted by the branch air volume control valve on the entire circumference. Thus, the relative tuyere airflow was controlled to be 70% or less with the average tuyere airflow divided by the number of tuyere as 100%.
The number of tuyere located within ± 30 ° in the circumferential direction was 5 in the case of this blast furnace out of the total number of tuyere of the blast furnace (depending on the internal volume of the blast furnace).
[0032]
After continuing this action for a week, the heat flux on the bottom wall of the blast furnace began to decline, and after 10 days it became below the reference value. After another 5 days, the branch air volume control valve is controlled so that the relative tuyere airflow of the 5 tuyere at the upper part of the ascending point becomes 80%. Controled by the branch air volume control valve so that the relative tuyere airflow of the tuyere is 90%, and after 10 days, the relative tuyere airflow of the 5 tuyere at the upper part of the ascending point is set to 100% Returned. As a result, after 30 days from the time when the heat flux at the furnace bottom side wall portion rose and exceeded the reference value, the heat flux at the furnace bottom side wall portion calmed down and returned to the original level.
[0033]
In FIG. 4, the brick temperature at the tip position of the thermocouple inserted into the brick at the bottom wall of the furnace bottom (normal insertion depth: 50 to 100 mm) is measured, and the temperature measurement value is set in advance. However, when the upper limit value was approached, or when the upper limit value was exceeded, measures were taken to prevent the above-mentioned furnace bottom side wall bricks from being worn. Because of this problem, the implementation of measures to reduce brick wear may be delayed from several hours to sometimes a day compared to when the reference method is implemented. The delay in the implementation of this brick wear suppression measure may have a fatal effect on the progress of brick wear on the bottom wall of the furnace bottom.
[0034]
( Reference Example 2) In a large blast furnace having an internal volume of 4000 m grade 3 and the number of tuyere of 35 fires, 11 years have passed since the blast furnace, the residual thickness including the viscous layer on the bottom wall of the blast furnace bottom was measured at four locations. The remaining thickness of the part became 700 mm or less of the reference value. Therefore, it is predicted that brick wear on the bottom wall of the furnace will progress, and the air flow rate at the tuyere located within ± 30 ° in the circumferential direction at the location where the remaining thickness has fallen below the reference value is installed in the air supply branch. Control was started by the branch pipe air flow control valve.
[0035]
As shown in FIG. 5, relative wings with an average tuyere blast volume obtained by dividing the blast volume of six tuyere located within ± 30 ° in the circumferential direction by the blast volume by the number of tuyere is 100%. It was controlled by a branch air volume control valve so that the air flow rate at the mouth was 70% or less.
Note that the number of tuyere located within ± 30 ° in the circumferential direction at the point where the remaining thickness has fallen below the standard value is the number of tuyere in the blast furnace (depending on the internal volume of the blast furnace). There were 6 places.
[0036]
After this action was continued for one week, the remaining thickness of the portion where the remaining thickness was reduced began to increase, and after 10 days, it exceeded the reference value. After another 5 days, the branch tuyere air volume control valve is controlled so that the relative tuyere airflow of the 6 tuyere at the upper part of the remaining thickness reduction part becomes 80%. Control is performed by the branch air volume control valve so that the relative tuyere airflow of the 6 tuyere at the lowered part becomes 90%. After 10 days have passed, the relatives of the 6 tuyere at the upper part of the remaining reduced thickness part The tuyere airflow was returned to 100%. As a result, after 30 days from the time when the residual thickness including the viscous layer on the bottom wall of the blast furnace decreased and became below the reference value, the residual thickness including the viscous layer on the high side wall was almost the original. Returned to the level.
[0037]
(Example 3)
Internal volume in a large blast furnace wings talkative is 38 present in the tertiary 5000 m, the heat flux from the furnace in blast furnace bottom central position to outside the furnace direction measured at one point, the heat flux reference value 700 W / m 2 or less.
One month after that point, it was judged that a viscous layer developed at the bottom of the blast furnace and there was a danger that the flow of the melt at the bottom of the furnace would head toward the annular flow.
If the melt flow at the bottom of the furnace is directed to an annular flow, it is predicted that brick wear of the bottom wall of the furnace will progress, and the residual thickness including the viscous layer on the bottom wall of the furnace has been below the reference value in the past The amount of air blown from the three tuyere at the upper part of was adjusted by a branch air volume control valve installed in the air branch.
[0038]
Specifically, as shown in FIG. 6, the branch air volume control valve was adjusted so that the relative tuyere air volume was 70% or less with the average tuyere air volume obtained by dividing the air volume by the number of tuyere as 100%. . After 20 days from the time when this action was taken, the heat flux at the center of the furnace began to rise first, and after 10 days, it exceeded the reference value. At that time, the heat flux at the bottom wall of the furnace bottom once started to rise also began to decrease.
[0039]
After 10 days have passed, the relative tuyere air flow rate of the upper tuyere at the upper part of two or three places where the residual thickness including the viscous layer has been below the reference value in the past will be 80%. Adjusted by the branch air volume control valve, and after 10 days have passed, the relative tuyere feed of the upper tuyere at the top two or three places where the remaining thickness including the viscous layer has become below the reference value in the past The air volume was returned to 100%. As a result, after 50 days from the time when the heat flux from the inside of the furnace bottom to the outside of the furnace decreases and falls below the reference value, the heat flux from the inside of the furnace bottom to the outside of the furnace decreases. It rose and almost returned to its original level.
[0040]
When the method of the present invention is carried out, the brick temperature at the tip position of the thermocouple inserted into the brick at the bottom wall of the furnace bottom (normal insertion depth: 50 to 100 mm) is measured, and the temperature measurement value When the temperature approaches the upper limit value set in advance or exceeds the upper limit value, the change in the brick temperature at the bottom wall of the bottom wall when the above-described measures for suppressing the wear of the bottom wall brick at the bottom of the furnace are implemented. This is shown in FIG.
[0041]
In the case of carrying out the method of the present invention, since the brick wear state of the bottom wall of the furnace bottom is predicted at an early stage as compared with the case of carrying out the conventional method, the implementation time of the countermeasure is earlier. Therefore, the rise level of the brick temperature at the bottom wall of the furnace bottom is small, and the decrease time of the brick temperature at the bottom wall of the furnace bottom after the countermeasure is reduced to the original level is also shorter than when the conventional method is performed.
[0042]
Example 4
Internal volume in a large blast furnace wings talkative is 38 present in the tertiary 5000 m, the heat flux from the furnace in blast furnace bottom central position to outside the furnace direction measured at one point, the heat flux reference value 700 W / m 2 or less.
Therefore, one month after that point, it was judged that a viscous layer developed at the bottom of the blast furnace and there was a danger that the flow of the melt at the bottom of the furnace would head toward the annular flow.
If the melt flow at the bottom of the furnace is directed to an annular flow, it is predicted that brick erosion of the bottom wall of the furnace will progress, and the residual thickness including the viscous layer on the bottom wall of the furnace is currently relatively thin. The air volume at the upper tuyere of the smallest, second and third smallest locations was adjusted by a branch air volume control valve installed in the air branch.
[0043]
As shown in FIG. 8, the branch air volume control valve was adjusted so that the relative tuyere air volume was 70% or less with the average tuyere air volume obtained by dividing the air volume by the number of tuyere as 100%. After the 20th day of this action, the heat flux at the center of the furnace began to rise first, and after 10 days, it exceeded the reference value. At that point, the heat flux at the bottom wall of the furnace once started to rise also began to decline.
[0044]
After 10 days, the relative tuyere airflow at the top of the smallest, second, and third smallest parts is reduced to 80% at the point where the remaining thickness including the viscous layer is relatively thin at present. After a further 10 days, the relative tuyere airflow at the top of the above-mentioned location, that is, the remaining thickness and the second and third smallest portions was returned to 100%. . As a result, after 50 days from the time when the heat flux from the inside of the furnace bottom to the outside of the furnace decreases and falls below the reference value, the heat flux from the inside of the furnace bottom to the outside of the furnace decreases. It rose and almost returned to its original level.
[0045]
When the method of the present invention is carried out, the brick temperature at the tip position of the thermocouple inserted into the brick at the bottom wall of the furnace bottom (normal insertion depth: 50 to 100 mm) is measured, and the temperature measurement value When the temperature approaches the upper limit value set in advance or exceeds the upper limit value, the change in the brick temperature at the bottom wall of the bottom wall when the above-described measures for suppressing the wear of the bottom wall brick at the bottom of the furnace are implemented. It is shown in FIG.
[0046]
In the case of carrying out the method of the present invention, since the brick wear state of the bottom wall of the furnace bottom is predicted at an early stage as compared with the case of carrying out the conventional method, the implementation time of the countermeasure is earlier. Therefore, the rise level of the brick temperature at the bottom wall of the furnace bottom is small, and the decrease time of the brick temperature at the bottom wall of the furnace bottom after the countermeasure is reduced to the original level is also shorter than when the conventional method is performed.
[0047]
【The invention's effect】
Using the method of the present invention, which is different from the conventional method for detecting the brick remaining thickness on the bottom wall of the furnace bottom according to the brick temperature indication value, the wear state of the brick on the bottom wall of the furnace bottom is detected quickly and accurately, and the degree of brick wear is reduced. Compared to the conventional method of detecting the brick temperature and taking countermeasures by adjusting the tuyere air flow control valve of the tuyere or the tuyere with large or large brick wear rate, It has become possible to prevent the brick temperature from rising and the brick temperature from rising significantly.
As a result, it has become possible to avoid a situation in which a significant reduction in production over a long period of time and an increase in hot metal costs due to measures to suppress brick wear on the bottom wall of the furnace bottom can be avoided.
[Brief description of the drawings]
[Fig. 1] Diagram showing boundary conditions during heat transfer calculation [Fig. 2] Diagram showing comparison of time differential value of heat flux and temperature for step response change in furnace by one-dimensional unsteady heat transfer analysis [Fig. 3] ] Figure showing the transition of the heat flux from the inside of the furnace bottom wall to the outside of the furnace at a certain location before and after the implementation of the reference method and the transition of the relative tuyere air flow of the tuyere where the action was performed. [Fig. 4] Reference method Fig. 5 shows a comparison of the timing of implementation of measures to suppress brick wear between the implementation and the conventional method. Fig. 5: Transition of remaining thickness including the viscous layer on the bottom wall of the furnace bottom at some locations before and after the implementation of the reference method and actions FIG. 6 is a graph showing the transition of the relative tuyere air flow of the tuyere, and FIG. 6 shows the transition of the heat flux from the inside of the furnace center to the outside of the furnace before and after the method of the present invention and the remaining thickness including the viscous layer. Fig. 7 shows the transition of the relative tuyere airflow at the upper tuyere at locations that have previously been below the reference value. FIG. 8 is a diagram showing a comparison of the timing of implementation of measures to suppress brick wear when the conventional method and the conventional method are implemented. FIG. 8 includes the transition of the heat flux from the center of the furnace bottom to the outside of the furnace before and after the present method and the viscous layer. Fig. 9 is a diagram showing the transition of the relative tuyere airflow at the two tuyere at the top of the location where the remaining thickness is minimized at the present time. Diagram showing time comparison 【Explanation of symbols】
1. 1.
7). Sprinkler
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12156297A JP4132128B2 (en) | 1997-04-25 | 1997-04-25 | Blast furnace operation method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12156297A JP4132128B2 (en) | 1997-04-25 | 1997-04-25 | Blast furnace operation method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10298621A JPH10298621A (en) | 1998-11-10 |
| JP4132128B2 true JP4132128B2 (en) | 2008-08-13 |
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| JP12156297A Expired - Fee Related JP4132128B2 (en) | 1997-04-25 | 1997-04-25 | Blast furnace operation method |
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| JP4598710B2 (en) * | 2006-03-30 | 2010-12-15 | 新日本製鐵株式会社 | Blast furnace brick wear prevention method |
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| JPH10298621A (en) | 1998-11-10 |
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