JP3855635B2 - Blast furnace operation method - Google Patents
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Description
【０００１】
【発明が属する技術分野】
この発明は、微粉炭を１８０ｋｇ／溶銑トン以上吹き込んで行う高炉の操業方法に関する。
【０００２】
【従来の技術】
通常、高炉操業では炉頂部から鉱石とコークスを交互に装入し、炉下部の羽口部から吹き込まれる１２００℃程度の熱風でコークスを燃焼させ、その発生したガスにより鉱石を還元して溶銑を得るものである。
最近の高炉操業では、コークス炉の寿命延長や溶銑コストの低減などを目的としてコークスの代わりに羽口部から微粉炭を吹き込む操業が主流となっており、その吹き込み量も年々増加する傾向にある。
【０００３】
微粉炭を溶銑トン当り１８０ｋｇ以上吹き込む高微粉炭吹込み操業においては、溶銑トン当りの鉱石装入量とコークス装入量の比（Ｏ／Ｃ比）の増加による装入物層内の空隙率の低下、溶銑トン当りの装入物と炉内ガスの熱容量比（熱流比）の低下による炉内ガス温度の上昇、それに伴う炉内ガス流速の増加といった原因により、炉内での通気抵抗及び圧損の増加を招くことが知られている。
【０００４】
【発明が解決しようとする課題】
このような状態が生じると、送風圧力の著しい上昇や装入物が安定して降下せずに炉上部に吹き上げられる吹き抜け現象が引き起こされ、その結果、高炉の安定操業が大きく阻害され、操業弾力性が著しく低下する。したがって、高微粉炭吹込み操業下での安定操業を実現するためには、炉内通気性を良好に保つことが極めて重要である。
したがって本発明の目的は、高微粉炭吹き込み操業において炉内通気性を良好に保ち、安定した操業を可能とする高炉の操業方法を提供することにある。
【０００５】
【課題を解決するための手段】
本発明者らは高微粉炭吹き込み操業、特に微粉炭を溶銑トン当り１８０ｋｇ以上吹き込んで行う高微粉炭吹き込み操業における炉内通気性の改善について詳細な検討を行い、その結果、Ｖbosh／Ｖin すなわち［送風空気量（Ｎｍ３／分）］×０．７９＋２×［送風空気量（Ｎｍ３／分）］×０．２１＋２×［送風空気中への酸素富化量（Ｎｍ３／分）］）／［高炉内容積（ｍ３）］で定義される高炉ボッシュ部（朝顔部）におけるガス量と高炉内容積の比と炉内通気抵抗との間に明確な相関関係があり、このＶbosh／Ｖinを制御することにより炉内通気性の改善が可能であること、具体的には炉内に装入されたコークスの熱間反応後強度ＣＳＲに応じてＶbosh／Ｖinを所定のレベル以下の範囲に制御することにより、高微粉炭吹き込み操業における炉内通気性を良好に保ち、安定した操業を行い得ることを見い出した。
【０００６】
本発明はこのような知見に基づきなされたもので、その特徴は以下のとおりである。
[1] 微粉炭を１８０ｋｇ／溶銑トン以上吹き込んで行う高炉の操業において、コークスの熱間反応後強度ＣＳＲに応じて、下記(1)及び(2)の条件を満足するように送風空気量と送風空気中への酸素富化量を制御することを特徴とする高炉の操業方法。
(1)炉内装入されるコークスの熱間反応後強度ＣＳＲが６０％未満の場合
Ｖbosh／Ｖin≦２．０５
(2)炉内装入されるコークスの熱間反応後強度ＣＳＲが６０％以上の場合
Ｖbosh／Ｖin≦２．２０
ここで、Ｖｂｏｓｈ／Ｖｉｎ：下式で定義される、高炉ボッシュ部におけるガス量と高炉内容積の比
（［送風空気量（Ｎｍ３／分）］×０．７９＋２×［送風空気量（Ｎｍ３／分）］×０．２１＋２×［送風空気中への酸素富化量（Ｎｍ３／分）］）／［高炉内容積（ｍ３）］
【０００７】
[2] 上記[1]の操業方法において、羽口先理論燃焼温度が１９５０℃以上となるよう、送風空気中への酸素富化量、送風温度、送風湿分の少なくとも１つを制御することを特徴とする高炉の操業方法。
【０００８】
【発明の実施の形態】
本発明は、微粉炭を１８０ｋｇ／溶銑トン以上吹き込んで行う高炉の操業において、炉内装入コークスの熱間強度指数に応じてＶbosh／Ｖin、すなわち下式、
（［送風空気量（Ｎｍ３／分）］×０．７９＋２×［送風空気量（Ｎｍ３／分）］×０．２１＋２×［送風空気中への酸素富化量（Ｎｍ３／分）］）／［高炉内容積（ｍ３）］
により定義される高炉ボッシュ部（朝顔部）におけるガス量と高炉内容積（高炉内全容積）の比が、下記(1)及び(2)の条件を満足するよう送風空気量と送風空気中への酸素富化量を制御する。
(1)炉内装入コークスの熱間反応後強度ＣＳＲが６０％未満の場合
Ｖbosh／Ｖin≦２．０５
(2)炉内装入コークスの熱間反応後強度ＣＳＲが６０％以上の場合
Ｖbosh／Ｖin≦２．２０
【０００９】
本発明において炉内装入コークスの熱間反応後強度ＣＳＲ（以下、単に“ＣＳＲ”という）に応じてＶbosh／Ｖinを異なる条件に制御するのは、炉内装入コークスは、そのＣＳＲにより炉内での粉コークスの発生量及び粒径低下の程度が異なるためである。
ここで、コークスのＣＳＲ（coke strength after reaction）は、粒径２０±１ｍｍのコークスをＣＯ２雰囲気中にて１１００℃で２時間加熱した後、室温でＩ型ドラム試験（２０ｒｐｍ×６０分）を行い、試験後の粒径９．５ｍｍ以上のコークスの割合（％）で表わされる。
【００１０】
図１は、微粉炭を１８０ｋｇ／溶銑トン以上吹き込んで行った高炉の実操業のデータに基づくＶbosh／Ｖinと炉内通気抵抗との関係の一例を示したものである。ここで、送風圧力Ｐｂ（ｋｇ／ｃｍ２）と炉頂圧力Ｐｔ（ｋｇ／ｃｍ２）との差であるＰｂ−Ｐｔは炉内通気抵抗を示す指標である。図１によれば、炉内装入されるコークスのＣＳＲが６０％未満の場合にはＶbosh／Ｖin≦２．０５、炉内装入されるコークスのＣＳＲが６０％以上の場合にはＶbosh／Ｖin≦２．２０を満足することにより、炉内通気抵抗の指標であるＰｂ−Ｐｔを１．６ｋｇ／ｃｍ２以下に抑えることができる。また、ＣＳＲが６０％以上のコークスを用いた場合にはＰｂ−Ｐｔが全体的に低下し、通気抵抗の改善に有効であることが判る。
【００１１】
ここで、Ｖbosh／Ｖinの制御は、例えば送風空気中への酸素富化量を調整することにより行うことができる。一般に、高炉操業においては溶銑生産量に応じて酸素原単位が決まるため、仮に生産量を一定とした場合には、送風空気中への酸素富化率が高いほどＶbosh／Ｖinの値は小さくなる。
本発明ではＶbosh／Ｖinの下限は特に規定しないが、高炉内でのガス流れの安定性を確保するという観点からは、１．５０程度を下限とすることが好ましい。
【００１２】
高炉内への微粉炭の吹き込み量を増大させた場合、一般に以下のような要因により炉内通気抵抗が増大するものと考えられる。
▲１▼ 微粉炭吹き込み量を増大させると、微粉炭吹き込み密度が上昇するため微粉炭と酸素との接触効率が低下し、微粉炭の燃焼効率が低下する。このため多量の未燃炭（未燃チャー）が生じることになるが、この未燃炭によるソリューションロス反応（ＣＯ２＋Ｃ→２ＣＯ）によって炉内のＣＯ２が消費されるため、コークスの粉化により生じたコークス粉がソリューションロス反応によって消費されにくくなる。このためコークス粉が炉芯部に滞留・蓄積され、炉内通気抵抗が増大することになる。
【００１３】
▲２▼ 微粉炭によるコークスの置換には限界があるため、微粉炭の吹き込み量を増加させると必然的に燃料比（コークス比＋微粉炭比）は増加する。したがって、これに伴い送風原単位が上昇するため炉内ガス流量が増大し、この結果、炉内通気抵抗が増大することになる。
▲３▼ 上記のように燃料比と送風原単位が上昇する結果、熱供給量が大きくなるので融着帯が炉の上部領域側に移行し、これに伴い融着帯の表面積が増大するため炉内通気抵抗が増大する。
▲４▼ 溶銑トン当りの鉱石装入量とコークス装入量の比（Ｏ／Ｃ比）が増加するため装入物層内の空隙率が低下し、炉内通気抵抗が増大する。
▲５▼ 燃料比の増大に伴ってスラグ比も増大するため、その分炉内通気抵抗が増大する。
【００１４】
このような要因による炉内通気抵抗の増大に対し、本発明法においてＶbosh／Ｖinを上記(1)及び(2)の条件に制御することにより、以下のような作用によって炉内通気抵抗が低減され、炉内通気性が改善されるものと考えられる。
(a) 送風空気中の酸素富化率が相対的に高められる結果、炉内における微粉炭の燃焼効率が改善されて未燃炭量が減少し、未燃炭によるソリューションロス反応が抑えられる。この結果、コークスの粉化により生じたコークス粉（コークス粉の発生量は炉内装入コークスのＣＳＲにより異なる）がソリューションロス反応によって消費され易くなり、炉芯部でのコークス粉の滞留・蓄積量が減少し、炉内通気抵抗が低下する。
【００１５】
(b) 炉内における微粉炭の燃焼効率が改善されるため微粉炭によるコークスの置換率が向上し、燃料比（コークス比＋微粉炭比）を低減させることができる。これに伴い送風原単位が低減するため炉内ガス流量が減少し、この結果炉内通気抵抗が低下する。
(c) 上記のように燃料比と送風原単位が低減される結果、熱供給量が小さくなるため融着帯を炉の下部領域側に維持することができ、この結果炉内通気抵抗が低下するる。
(d) 燃料比が低減することにともなってスラグ比も低減するため、その分炉内通気抵抗が低下する。
【００１６】
さらに、本発明の高炉操業では、羽口先理論燃焼温度（以下、ＴＦＴという）が１９５０℃以上となるように送風空気中への酸素富化量、送風温度、送風湿分の少なくとも１つを制御することが好ましい。
ここで、ＴＦＴとは羽口先でコークス及び微粉炭が燃焼する時のフレーム温度であり、このフレーム温度は炉熱に大きな影響を及ぼす。このＴＦＴは下式（ラムの式）により計算される。
ＴＦＴ＝（２４５０＋Ｑｆ＋Ｑｂ＋Ｑｃ）／（Ｃｇ・Ｖｇ）
但し Ｑｆ：送風燃料反応熱（ｋｃａｌ／ｋｇＣ，Ｃ：羽口先で燃焼するＣ）
Ｑｂ：送風顕熱（ｋｃａｌ／ｋｇＣ，Ｃ：羽口先で燃焼するＣ）
Ｑｃ：羽口先の燃焼帯に流入するコークス顕熱（ｋｃａｌ／ｋｇＣ，Ｃ：羽口先で燃焼するＣ）
Ｃｇ：生成ガス定圧比熱（ｋｃａｌ／Ｎｍ３・℃）
Ｖｇ：生成ガス量（Ｎｍ３／ｋｇＣ，Ｃ：羽口先で燃焼するＣ）
【００１７】
このＴＦＴを１９５０℃以上とすることにより微粉炭の燃焼性が維持され、炉内通気性の改善がより効果的に促進されるとともに、供給熱量の確保も促進される。
図２はＴＦＴと微粉炭吹込量との関係を示すもので、微粉炭の吹き込み量を増大させるとＶＭ（揮発分）の分解熱のためにＱｆが減少し、ＴＦＴが低下する。そして、ＴＦＴが１９５０℃以下になると炉況の不安定化が顕在化する。
【００１８】
ＴＦＴを高めて炉況の不安定化を回避するには酸素富化率を高めることが有効であり、送風空気中の酸素濃度の上昇によりＣＯ燃焼熱の発生が促進される結果、微粉炭吹き込み量の増大に伴うＱｆの減少が抑えられる。また、ＴＦＴを上昇させるには送風温度の上昇、送風添加湿分の低減化なども有効であり、これらの１つ以上を制御することにより、所望のＴＦＴを得ることができる。
【００１９】
【実施例】
実機高炉において、表１に示す条件で高微粉炭吹き込み操業を実施した。その結果を表１に併せて示す。
【００２０】
【表１】
【発明の効果】
以上述べたように本発明法によれば、高炉内に微粉炭を１８０ｋｇ／溶銑トン以上吹き込んで行う高微粉炭吹き込み操業において、炉内通気抵抗を効果的に低減させ、安定した操業を実施することができる。
【図面の簡単な説明】
【図１】高炉の実操業のデータに基づくＶbosh／Ｖinと炉内通気抵抗との関係を示すグラフ
【図２】微粉炭吹込量とＴＦＴとの関係を示すグラフ[0001]
[Technical field to which the invention belongs]
The present invention relates to a method for operating a blast furnace in which pulverized coal is blown in at least 180 kg / ton of hot metal.
[0002]
[Prior art]
Normally, in blast furnace operation, ore and coke are alternately charged from the top of the furnace, the coke is burned with hot air of about 1200 ° C blown from the tuyere at the bottom of the furnace, and the ore is reduced by the generated gas to produce molten iron. To get.
In recent blast furnace operations, pulverized coal is blown from the tuyere instead of coke for the purpose of extending the life of the coke oven and reducing hot metal costs, and the amount of blown air tends to increase year by year. .
[0003]
In high pulverized coal injection operation in which pulverized coal is blown over 180 kg per ton of hot metal, the porosity in the charge layer due to an increase in the ratio of Ore charge to coke charge (O / C ratio) per ton of hot metal The resistance to air flow in the furnace and the increase in the gas temperature in the furnace due to the decrease in the heat capacity ratio (heat flow ratio) between the charge per ton of molten iron and the gas in the furnace (heat flow ratio) It is known to cause an increase in pressure loss.
[0004]
[Problems to be solved by the invention]
When such a situation occurs, a significant increase in the blowing pressure and a blow-through phenomenon in which the charge is blown up to the upper part of the furnace without being stably lowered are caused. As a result, the stable operation of the blast furnace is greatly hindered, and the operation elasticity Remarkably deteriorates. Therefore, in order to realize a stable operation under the operation of blowing high pulverized coal, it is extremely important to maintain good furnace air permeability.
Accordingly, an object of the present invention is to provide a method of operating a blast furnace that maintains good air permeability in the furnace and enables stable operation in the operation of blowing high pulverized coal.
[0005]
[Means for Solving the Problems]
The present inventors have conducted a detailed study on improvement of the air permeability in the furnace in the high pulverized coal injection operation, particularly in the high pulverized coal injection operation performed by injecting pulverized coal by 180 kg or more per ton of molten iron. As a result, Vbosh / Vin, blowing air volume (Nm 3 / min)] × 0.79 + 2 × [blown air amount (Nm 3 / min)] oxygen enrichment amount to × 0.21 + 2 × [blown air (Nm 3 / min)]) / There is a clear correlation between the ratio of the gas amount in the blast furnace bosch part (morning glory part) defined by [Blast furnace inner volume (m 3 )], the ratio of the blast furnace inner volume, and the ventilation resistance in the furnace, and this Vbosh / Vin It is possible to improve the air permeability in the furnace by controlling, and specifically, Vbosh / Vin is controlled within a predetermined level or less according to the strength CSR after the hot reaction of the coke charged in the furnace. By doing so, the high pulverized coal injection operation That maintaining good in ventilation oven and found that can perform stable operation.
[0006]
The present invention has been made based on such findings, and the features thereof are as follows.
[1] In the operation of a blast furnace where pulverized coal is blown at 180 kg / tonn of hot metal or more, depending on the strength CSR after the hot reaction of coke, the amount of blast air should satisfy the following conditions (1) and (2) A method for operating a blast furnace, characterized by controlling the amount of oxygen enriched in the blown air.
(1) When the strength CSR after hot reaction of the coke put into the furnace interior is less than 60% Vbosh / Vin ≦ 2.05
(2) When the strength CSR after hot reaction of the coke put into the furnace interior is 60% or more Vbosh / Vin ≦ 2.20
Here, Vbosh / Vin: ratio of gas amount and blast furnace internal volume in the blast furnace bosch part defined by the following formula ([blast air amount (Nm 3 /min)]×0.79+2×[blast air amount (Nm 3 /Min)]×0.21+2×[amount of oxygen enriched in the blown air (Nm 3 / min)]) / [volume in the blast furnace (m 3 )]
[0007]
[2] In the operation method of [1] above, controlling the oxygen enrichment amount in the blown air, the blown temperature, and the blown moisture so that the theoretical combustion temperature at the tip of the tuyere is 1950 ° C. or higher. A featured blast furnace operation method.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the operation of a blast furnace in which pulverized coal is blown in at least 180 kg / tonn of hot metal, the present invention is based on Vbosh / Vin, that is,
([Amount of blown air (Nm 3 /min)]×0.79+2×[Amount of blown air (Nm 3 /min)]×0.21+2×[Amount of oxygen enriched in the blown air (Nm 3 / min)] ) / [Blast furnace volume (m 3 )]
The ratio of the gas amount in the blast furnace bosch part (morning glory part) and the volume in the blast furnace (total volume in the blast furnace) defined by the following conditions (1) and (2): Control the amount of oxygen enrichment.
(1) When the strength CSR after hot reaction of the coke inside the furnace is less than 60% Vbosh / Vin ≦ 2.05
(2) When the strength CSR after hot reaction of coke in the furnace interior is 60% or more Vbosh / Vin ≦ 2.20
[0009]
In the present invention, Vbosh / Vin is controlled in different conditions depending on the strength CSR after hot reaction of the coke inside the furnace (hereinafter simply referred to as “CSR”). This is because the amount of generated powder coke and the degree of particle size reduction differ.
Here, the CSR (coke strength after reaction) of coke is obtained by heating a coke having a particle size of 20 ± 1 mm in a CO 2 atmosphere at 1100 ° C. for 2 hours, and then performing a type I drum test (20 rpm × 60 minutes) at room temperature. This is expressed as a ratio (%) of coke having a particle diameter of 9.5 mm or more after the test.
[0010]
FIG. 1 shows an example of the relationship between Vbosh / Vin and in-furnace ventilation resistance based on actual operation data of a blast furnace in which pulverized coal is blown into 180 kg / tonn of hot metal or more. Here, Pb−Pt, which is the difference between the blowing pressure Pb (kg / cm 2 ) and the furnace top pressure Pt (kg / cm 2 ), is an index indicating the furnace ventilation resistance. According to FIG. 1, Vbosh / Vin ≦ 2.05 when the CSR of the coke put into the furnace is less than 60%, and Vbosh / Vin ≦ when the CSR of the coke put into the furnace is 60% or more. By satisfying 2.20, it is possible to suppress Pb—Pt, which is an index of furnace ventilation resistance, to 1.6 kg / cm 2 or less. In addition, when coke having a CSR of 60% or more is used, Pb-Pt decreases as a whole, and it can be seen that it is effective in improving the airflow resistance.
[0011]
Here, the control of Vbosh / Vin can be performed, for example, by adjusting the amount of oxygen enrichment into the blown air. In general, since the oxygen intensity is determined according to the hot metal production in the blast furnace operation, if the production is made constant, the value of Vbosh / Vin becomes smaller as the oxygen enrichment rate in the blown air becomes higher. .
In the present invention, the lower limit of Vbosh / Vin is not particularly specified, but from the viewpoint of ensuring the stability of the gas flow in the blast furnace, it is preferable to set the lower limit to about 1.50.
[0012]
When the amount of pulverized coal blown into the blast furnace is increased, it is generally considered that the furnace ventilation resistance increases due to the following factors.
(1) When the amount of pulverized coal injection is increased, the pulverized coal injection density is increased, so that the contact efficiency between the pulverized coal and oxygen decreases, and the combustion efficiency of the pulverized coal decreases. Therefore it would be a large amount of unburned (unburned char) occurs, because the CO 2 in the furnace is consumed by the solution loss reaction due to the unburned (CO 2 + C → 2CO), caused by pulverization of the coke Coke powder is not easily consumed by the solution loss reaction. For this reason, coke powder stays and accumulates in the furnace core, and the ventilation resistance in the furnace increases.
[0013]
(2) Since the replacement of coke with pulverized coal is limited, the fuel ratio (coke ratio + pulverized coal ratio) inevitably increases when the amount of pulverized coal injected is increased. Accordingly, since the blast intensity increases, the in-furnace gas flow rate increases, and as a result, the in-furnace ventilation resistance increases.
(3) As a result of the increase in the fuel ratio and the basic unit of blast as described above, the heat supply amount increases, so that the cohesive zone moves to the upper region side of the furnace, and the surface area of the cohesive zone increases accordingly. Increases the ventilation resistance in the furnace.
(4) The ratio of ore charge to coke charge (O / C ratio) per ton of hot metal increases, so the porosity in the charge layer decreases, and the ventilation resistance in the furnace increases.
(5) Since the slag ratio increases as the fuel ratio increases, the in-furnace resistance increases accordingly.
[0014]
By controlling Vbosh / Vin to the above conditions (1) and (2) in the method of the present invention against the increase in furnace ventilation resistance due to such factors, the furnace ventilation resistance is reduced by the following actions. It is thought that the air permeability in the furnace is improved.
(a) As a result of relatively increasing the oxygen enrichment rate in the blown air, the combustion efficiency of pulverized coal in the furnace is improved, the amount of unburned coal is reduced, and the solution loss reaction due to unburned coal is suppressed. As a result, coke powder generated by coke pulverization (the amount of coke powder generated differs depending on the CSR of the coke inside the furnace) is likely to be consumed by the solution loss reaction, and the amount of coke powder that accumulates and accumulates in the furnace core. Decreases and the resistance to ventilation in the furnace decreases.
[0015]
(b) Since the combustion efficiency of pulverized coal in the furnace is improved, the replacement rate of coke with pulverized coal is improved, and the fuel ratio (coke ratio + pulverized coal ratio) can be reduced. Along with this, since the basic unit of blast is reduced, the gas flow rate in the furnace is reduced, and as a result, the furnace ventilation resistance is lowered.
(c) As a result of the reduction of the fuel ratio and the basic unit of blast as described above, the heat supply amount is reduced, so that the cohesive zone can be maintained on the lower region side of the furnace, resulting in a decrease in the furnace ventilation resistance. To do.
(d) Since the slag ratio is reduced as the fuel ratio is reduced, the ventilation resistance in the furnace is lowered accordingly.
[0016]
Further, in the operation of the blast furnace according to the present invention, at least one of oxygen enrichment amount, blowing temperature, and blowing moisture in the blown air is controlled so that the tuyere tip theoretical combustion temperature (hereinafter referred to as TFT) is 1950 ° C. or higher. It is preferable to do.
Here, TFT is a flame temperature when coke and pulverized coal burn at the tuyere, and this flame temperature has a great influence on the furnace heat. This TFT is calculated by the following formula (Lamb's formula).
TFT = (2450 + Qf + Qb + Qc) / (Cg · Vg)
However, Qf: blast fuel reaction heat (kcal / kgC, C: C combusted at the tuyere)
Qb: blown sensible heat (kcal / kgC, C: C burning at the tuyere)
Qc: Coke sensible heat flowing into the combustion zone at the tuyere (kcal / kgC, C: C burning at the tuyere)
Cg: generated gas constant pressure specific heat (kcal / Nm 3 ° C.)
Vg: amount of generated gas (Nm 3 / kgC, C: C burning at the tuyere)
[0017]
By setting the TFT to 1950 ° C. or higher, the combustibility of the pulverized coal is maintained, the improvement of the air permeability in the furnace is more effectively promoted, and the securing of the supply heat amount is also promoted.
FIG. 2 shows the relationship between TFT and the amount of pulverized coal injection. When the amount of pulverized coal injection is increased, Qf decreases due to the decomposition heat of VM (volatile matter), and the TFT decreases. And when TFT becomes 1950 degrees C or less, the destabilization of a furnace condition will become obvious.
[0018]
Increasing the oxygen enrichment rate is effective in increasing the TFT and avoiding destabilization of the furnace conditions, and as a result of increasing the oxygen concentration in the blown air, the generation of CO combustion heat is promoted. A decrease in Qf accompanying an increase in the amount can be suppressed. In order to raise the TFT, it is also effective to raise the blowing temperature, reduce the amount of moisture added to the blowing, and the like, and a desired TFT can be obtained by controlling one or more of these.
[0019]
【Example】
In the actual blast furnace, high pulverized coal blowing operation was performed under the conditions shown in Table 1. The results are also shown in Table 1.
[0020]
[Table 1]
【The invention's effect】
As described above, according to the method of the present invention, in the operation of injecting pulverized coal into the blast furnace at 180 kg / tonn of molten iron or more, the blast furnace is effectively reduced by reducing the resistance to ventilation in the furnace. be able to.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between Vbosh / Vin and furnace ventilation resistance based on actual blast furnace operation data. FIG. 2 is a graph showing the relationship between pulverized coal injection amount and TFT.
Claims (2)
(1)炉内装入されるコークスの熱間反応後強度ＣＳＲが６０％未満の場合
Ｖbosh／Ｖin≦２．０５
(2)炉内装入されるコークスの熱間反応後強度ＣＳＲが６０％以上の場合
Ｖbosh／Ｖin≦２．２０
ここで、Ｖｂｏｓｈ／Ｖｉｎ：下式で定義される、高炉ボッシュ部におけるガス量と高炉内容積の比
（［送風空気量（Ｎｍ３／分）］×０．７９＋２×［送風空気量（Ｎｍ３／分）］×０．２１＋２×［送風空気中への酸素富化量（Ｎｍ３／分）］）／［高炉内容積（ｍ３）］In the operation of a blast furnace where pulverized coal is blown in at least 180 kg / tonn of hot metal, depending on the strength CSR after the hot reaction of coke, the amount of blown air and the blown air should satisfy the following conditions (1) and (2) A method of operating a blast furnace characterized by controlling the amount of oxygen enrichment to the blast furnace.
(1) When the strength CSR after hot reaction of the coke put into the furnace interior is less than 60% Vbosh / Vin ≦ 2.05
(2) When the strength CSR after hot reaction of the coke put into the furnace interior is 60% or more Vbosh / Vin ≦ 2.20
Here, Vbosh / Vin: ratio of gas amount and blast furnace internal volume in the blast furnace bosch part defined by the following formula ([blast air amount (Nm 3 /min)]×0.79+2×[blast air amount (Nm 3 /Min)]×0.21+2×[amount of oxygen enriched in the blown air (Nm 3 / min)]) / [volume in the blast furnace (m 3 )]
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| KR101246436B1 (en) | 2011-09-28 | 2013-03-21 | 현대제철 주식회사 | Prediction method for product measuring of pig iron |
| JP6337613B2 (en) * | 2014-05-23 | 2018-06-06 | 新日鐵住金株式会社 | Blast furnace operation method |
| JP7310858B2 (en) * | 2020-09-25 | 2023-07-19 | Ｊｆｅスチール株式会社 | Blast furnace operation method |
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