JP2008240028A - Method for operating blast furnace - Google Patents

Method for operating blast furnace Download PDF

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JP2008240028A
JP2008240028A JP2007079462A JP2007079462A JP2008240028A JP 2008240028 A JP2008240028 A JP 2008240028A JP 2007079462 A JP2007079462 A JP 2007079462A JP 2007079462 A JP2007079462 A JP 2007079462A JP 2008240028 A JP2008240028 A JP 2008240028A
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furnace
coke
scrap
blast furnace
raw material
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Yusuke Kashiwabara
佑介 柏原
Takeshi Sato
健 佐藤
Michitaka Sato
道貴 佐藤
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JFE Steel Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for operating a blast furnace by which even in the blast furnace operation using a high RDI sintered ore, a low DI coke and low quality raw fuel, the stable operation can be succeeded at a low cost without increasing reducing material ratio. <P>SOLUTION: In the blast furnace operation alternately charging iron oxide raw material and coke from the furnace top, when the sintered ore is used at least as a part of the iron oxide raw material, in the case of being reducing-powdering index in the sintered ore to the reference value or more, this method for operating the blast furnace is used as the followings, that is; a part of the iron oxide raw material is substituted into scrap without increasing reducing material ratio to keep the gas-permeability in the furnace. Otherwise, in the case of being the strength index of the coke to the reference value or lower, the method for operating the blast furnace is used as the followings, that is; a part of the iron oxide raw material is substituted into the scrap without increasing the reducing material ratio to keep the gas-permeability in the furnace. It is desirable that the scrap is charged into the center part of the furnace. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、高炉の操業方法に関し、特に炉頂から装入される原燃料品質の変動に対応して、還元材比を維持しながら、安定した操業を可能にする、高炉操業方法に関する。   The present invention relates to a method for operating a blast furnace, and more particularly, to a method for operating a blast furnace that enables stable operation while maintaining a reducing material ratio in response to fluctuations in raw fuel quality charged from the top of the furnace.

高炉は巨大な向流移動層反応炉であり、炉頂部から酸化鉄を主体とする鉄原料である酸化鉄原料（焼結鉱や魂鉱石）とコークスとを装入し、炉下部の羽口から吹き込まれる熱風によりコークスを燃焼させ、生成したＣＯを含む還元性ガスで酸化鉄原料中の酸化鉄を還元し、銑鉄を製造する。近年では環境問題の観点から、高炉操業は低還元材比操業を指向しているが、この場合には、コークス比の低下により炉内の通気抵抗が増大する。そのため、粉発生量の少ない高炉装入物を使用することにより、通気改善を図る必要があり、一般的には、焼結鉱の還元粉化性改善による通気性改善、および、コークスの冷間強度上昇による通気性改善が実施されている。   The blast furnace is a huge counter-current moving bed reactor, charged with iron oxide raw material (sintered or soul ore) and coke from the top of the furnace, mainly iron oxide, and tuyere at the bottom of the furnace The coke is burned with hot air blown from, and the iron oxide in the iron oxide raw material is reduced with the reducing gas containing CO produced to produce pig iron. In recent years, from the viewpoint of environmental problems, blast furnace operation is directed to low reductant ratio operation, but in this case, the resistance to ventilation in the furnace increases due to the reduction of the coke ratio. Therefore, it is necessary to improve ventilation by using a blast furnace charge that generates a small amount of powder. Generally, improvement of air permeability by improving reduced powdering property of sintered ore, and cold coke Breathability has been improved by increasing strength.

焼結鉱の還元粉化性は還元粉化指数（ＲＤＩ）で、コークスの冷間強度はドラム試験１５０回転指数（ＤＩ）で、それぞれ数値化されている。焼結鉱の還元粉化性の改善（低ＲＤＩ化）、および、コークスの冷間強度改善（高ＤＩ化）は、炉内における粉の発生量を低減し、通気性を改善することによって、高炉操業の安定性に寄与することが知られている。しかし、焼結鉱の還元粉化の対策として行われる低ＲＤＩ化、および、コークス粉化の対策として行われる高ＤＩ化は、それぞれ高品位の鉄鉱石、および、石炭を原料として行なう必要があるため、製造コストを増大させる傾向にある。   The reduced powdering property of sintered ore is a reduced powdering index (RDI), and the cold strength of coke is digitized by a drum test 150 rotation index (DI). Improvement of reduced powdering property of sintered ore (low RDI) and cold strength improvement of coke (higher DI) are achieved by reducing the amount of powder generated in the furnace and improving air permeability. It is known to contribute to the stability of blast furnace operation. However, low RDI, which is performed as a measure for reducing powdered sinter, and high DI, which is used as a measure for coke pulverization, must be performed using high-grade iron ore and coal as raw materials, respectively. Therefore, the manufacturing cost tends to increase.

高品位の鉄鉱石、石炭を用いないでも、炉内における粉の発生量を低減することのできる高炉操業方法として、特許文献１に原料の一部または全部が還元率１１〜３０％に還元されている原料を高炉に装入する方法が開示されている。
特開２００２−２５６３１０号公報 As a blast furnace operation method that can reduce the amount of powder generated in the furnace without using high-grade iron ore and coal, Patent Document 1 reduces part or all of the raw material to a reduction rate of 11 to 30%. A method for charging the raw material into a blast furnace is disclosed.
JP 2002-256310 A

しかし、特許文献１に記載の方法では、回転炉床炉などのクロスフロー型移動層や、シャフト型移動層を用いて鉄鉱石中のＦｅ2０3を全て還元してＦｅ3０4やＦｅＯの状態に変化させて還元率１１〜３０％に還元された鉄原料を製造する必要があるため、新たな設備投資が必要となり、やはりコスト高である。 However, in the method described in Patent Document 1, all of Fe 2 O 3 in iron ore is reduced by using a cross-flow type moving bed such as a rotary hearth furnace or a shaft type moving bed, and Fe 3 0 4 or FeO. Since it is necessary to manufacture the iron raw material reduced to a reduction rate of 11 to 30% by changing to the state of (1), a new capital investment is required, which is also expensive.

したがって本発明の目的は、このような従来技術の課題を解決し、高ＲＤＩ焼結鉱、および、低ＤＩコークスのような、低品位な原燃料を使用した高炉操業においても、還元材比を増加させずに、安定した操業を、低コストで継続することができる高炉操業方法を提供することにある。   Therefore, the object of the present invention is to solve such problems of the prior art, and to reduce the ratio of reducing materials even in blast furnace operation using low grade raw fuel such as high RDI sintered ore and low DI coke. An object of the present invention is to provide a blast furnace operating method capable of continuing stable operation at a low cost without increasing it.

本発明では、上記課題を解決するために、高炉へスクラップを装入する方法に着目し、以下の本発明を完成した。
（１）炉頂から酸化鉄原料とコークスとを交互に装入する高炉操業であって、前記酸化鉄原料の少なくとも一部として焼結鉱を使用する際に、前記焼結鉱の還元粉化指数が基準値以上の場合には、還元材比を増加させることなく前記酸化鉄原料の一部をスクラップで代替することで、炉内の通気性を維持することを特徴とする高炉操業方法。
（２）炉頂から酸化鉄原料とコークスとを交互に装入する高炉操業において、前記コークスの強度指数が基準値以下の場合には、還元材比を増加させることなく前記酸化鉄原料の一部をスクラップで代替することで、炉内の通気性を維持することを特徴とする高炉操業方法。
（３）スクラップを炉中心部に装入することを特徴とする（１）または（２）に記載の高炉操業方法。 In the present invention, in order to solve the above-mentioned problems, attention was paid to a method of charging scrap into a blast furnace, and the following present invention was completed.
(1) A blast furnace operation in which an iron oxide raw material and coke are alternately charged from the furnace top, and when the sintered ore is used as at least a part of the iron oxide raw material, the sintered ore is reduced to powder. A blast furnace operating method characterized by maintaining air permeability in a furnace by replacing a part of the iron oxide raw material with scrap without increasing the reducing material ratio when the index is equal to or higher than a reference value.
(2) In blast furnace operation in which iron oxide raw material and coke are alternately charged from the furnace top, when the strength index of the coke is below a reference value, the iron oxide raw material is increased without increasing the reducing material ratio. A method of operating a blast furnace characterized by maintaining the air permeability in the furnace by replacing the part with scrap.
(3) The blast furnace operating method according to (1) or (2), wherein scrap is charged into a furnace center.

本発明によれば、還元材比を増加させることなく、高ＲＤＩ焼結鉱、および、低ＤＩコークスを使用しながら、炉内の通気性を良好に維持した、安定的な高炉操業が可能となる。   According to the present invention, it is possible to perform stable blast furnace operation while maintaining good air permeability in the furnace while using high RDI sintered ore and low DI coke without increasing the reducing material ratio. Become.

本発明者らは、上記の課題を解決するために、高炉へスクラップを装入する方法に着目した。高炉の鉄原料としてスクラップを用いると、スクラップは、溶融するまでは、ほとんど収縮することなく形状を保ったまま炉内を降下していくと考えられるため、スクラップ装入によって、炉内の通気性を改善することができる、さらに、スクラップは金属鉄の状態であるために粉化の恐れはなく、炉内の通気性を確保して、高炉の安定した操業を継続することができると考えた。   In order to solve the above-mentioned problems, the present inventors have paid attention to a method of charging scrap into a blast furnace. When scrap is used as the raw material for iron in the blast furnace, it is considered that the scrap will move down in the furnace with almost no shrinkage until it melts. In addition, because the scrap is in the state of metallic iron, there is no fear of pulverization, and it was thought that stable operation of the blast furnace could be maintained by ensuring air permeability in the furnace. .

以上のことから、従来よりもＲＤＩの高い焼結鉱、および、ＤＩの低いコークスを使用する操業を行なう際には炉内発生粉が増加するが、スクラップを装入することで、スクラップ装入前と同じ炉内粉率を維持できるため、炉内の通気性を維持することが可能であると予想される。そこで、還元粉化指数（ＲＤＩ）の高い焼結鉱、冷間強度（ＤＩ）の低いコークスを使用する場合は、炉内通気性が悪化する前に、炉頂から装入する酸化鉄原料の一部をスクラップと代替する。   From the above, when operation using sintered ore with a higher RDI and coke with a lower DI is performed, the amount of powder generated in the furnace increases, but by charging the scrap, Since the same furnace powder rate as before can be maintained, it is expected that the air permeability in the furnace can be maintained. Therefore, when using sintered ore with a high reduced powder index (RDI) and coke with a low cold strength (DI), the iron oxide raw material charged from the top of the furnace is deteriorated before the air permeability in the furnace deteriorates. Substitute part for scrap.

高炉に装入する酸化鉄原料のうち、焼結鉱とスクラップとを置換して装入することが、焼結鉱に由来する炉内発生粉も低減させることができるため、通気性改善には特に効果的であると考えられる。   Of the iron oxide raw materials charged in the blast furnace, replacing the sintered ore with scrap can reduce the generated powder in the furnace derived from the sintered ore. It is considered to be particularly effective.

高炉内におけるスクラップの挙動を調査するため、図１に示す装置を用いて荷重軟化試験を行った（実験１）。図１の装置は、内径５０ｍｍφの黒鉛るつぼ１を加熱炉２内に設置し、黒鉛るつぼ１の下部からＣＯ、ＣＯ2、Ｎ2ガス３を流し、上部から排ガス４を排出させて、高炉内を模擬させた温度、ガス組成、荷重をプログラムで制御するものである。黒鉛るつぼ１内には、１辺が１０ｍｍのスクラップと、粒径が４．８ｍｍ〜６．７ｍｍの焼結鉱とについて、それぞれの比率を変えて填充した条件で実験を行った。比較のために、焼結鉱のみを填充した場合についても実験を行った。実験は、与えられた条件下で昇温還元を行い、黒鉛るつぼ１の底から試料が溶け落ちるまで続けた。実験中は、黒鉛るつぼ１内の上下の圧力差である炉差圧（ΔＰ）を連続的に測定した。図２にその測定された炉差圧の最大値と、黒鉛るつぼ１内のスクラップの質量割合であるスクラップ比率との関係を示す。スクラップの装入によりスクラップ比率が増加すると、炉差圧の最大値が低下した。これは、スクラップは焼結鉱と比較して収縮抵抗が大きいため、層内の空隙が確保されるためと考えられる。このことからスクラップの装入により通気性が改善されることが分かる。 In order to investigate the behavior of scrap in the blast furnace, a load softening test was conducted using the apparatus shown in FIG. 1 (Experiment 1). In the apparatus of FIG. 1, a graphite crucible 1 having an inner diameter of 50 mmφ is installed in a heating furnace 2, CO, CO 2 , N 2 gas 3 is allowed to flow from the lower part of the graphite crucible 1, and exhaust gas 4 is discharged from the upper part. The temperature, gas composition, and load simulating the above are controlled by a program. The graphite crucible 1 was subjected to an experiment under the condition that a scrap having a side of 10 mm and a sintered ore having a particle diameter of 4.8 mm to 6.7 mm were filled with varying ratios. For comparison, an experiment was also conducted in the case where only the sintered ore was filled. The experiment was performed under temperature-reducing conditions, and continued until the sample melted from the bottom of the graphite crucible 1. During the experiment, the furnace differential pressure (ΔP), which is the pressure difference between the upper and lower sides in the graphite crucible 1, was continuously measured. FIG. 2 shows the relationship between the measured maximum value of the furnace differential pressure and the scrap ratio, which is the mass ratio of scrap in the graphite crucible 1. When the scrap ratio increased due to scrap charging, the maximum value of the furnace differential pressure decreased. This is presumably because the voids in the layer are secured because the scrap has a larger shrinkage resistance than the sintered ore. This shows that the air permeability is improved by the introduction of scrap.

また、同様の方法を用いて、還元粉化指数（ＲＤＩ）の異なる焼結鉱を使用した場合について、焼結鉱のみを填充した場合の実験を行った。図３に測定された炉差圧の最大値と焼結鉱のＲＤＩとの関係を示す。還元粉化指数（ＲＤＩ）の増加により炉差圧の最大値が増加することは、通気性悪化を示している。しかしながら、還元粉化指数（ＲＤＩ）の高い焼結鉱を使用する場合でも、スクラップ装入の併用により炉内の通気性を改善することで、通気性を維持することができると考えられる。   Moreover, about the case where the sintered ore from which a reduced powdering index (RDI) differs was used using the same method, the experiment at the time of filling only a sintered ore was conducted. FIG. 3 shows the relationship between the maximum value of the furnace differential pressure measured and the RDI of the sintered ore. An increase in the maximum value of the furnace differential pressure due to an increase in the reduced powder index (RDI) indicates a deterioration in air permeability. However, even when using a sintered ore having a high reduced powder index (RDI), it is considered that the air permeability can be maintained by improving the air permeability in the furnace by the combined use of scrap charging.

次に冷間強度（ＤＩ）の低いコークスを使用する場合について検討する。コークスの炉内における粉発生挙動を調査するため、図４に示す装置を用いて燃焼試験を行った（実験２）。図４の装置は、高炉の羽口からレースウェイを模擬したもので、内部空間が幅１０００ｍｍで高さ１４００ｍｍの燃焼試験容器１０内にコークス充填層１１を形成し、そこにブローパイプ１２を１本挿入したものである。実験条件は熱風１３の吹込みを送風量３５０Ｎｍ3／ｈ、酸素富化率３体積％とし、微粉炭１４をブローパイプ１２内に１５０ｋｇ／ｔ相当で吹き込んだ。コークス供給量は、コークス充填層１１高さが一定となるように専用ホッパーからコークスを切り出すことで調整した。１５はコークス投入口、１６は排ガス排出口である。実験終了後に装置を解体してレースウェイ１７直上部の図中破線で囲んだサンプリング領域１８からコークスを採取し、粒径３ｍｍ以下（−３ｍｍ）の粉率を測定した。冷間強度（ＤＩ）の異なるコークスを用いて実験を行ない、コークスの粉率を測定した結果を図５に示す。図５に示すように、低ＤＩコークスを用いた場合は、充填層内における粉率が高いことが確認された。しかしながら、冷間強度（ＤＩ）の低いコークスを使用する場合でも、スクラップ装入の併用により炉内に空隙が確保されることによって通気性が改善されるため、低ＤＩコークスを使用して炉内粉率が増加した場合でも、通気性を維持することができると考えられる。 Next, a case where coke having a low cold strength (DI) is used will be examined. In order to investigate the generation behavior of coke in the furnace, a combustion test was conducted using the apparatus shown in FIG. 4 (Experiment 2). The apparatus of FIG. 4 simulates a raceway from the tuyere of a blast furnace. A coke packed bed 11 is formed in a combustion test vessel 10 having an internal space of 1000 mm in width and 1400 mm in height, and a blow pipe 12 is placed there. This is inserted. The experimental conditions were that hot air 13 was blown at an air flow rate of 350 Nm 3 / h and an oxygen enrichment rate of 3 vol%, and pulverized coal 14 was blown into the blow pipe 12 at an equivalent of 150 kg / t. The coke supply amount was adjusted by cutting the coke from the dedicated hopper so that the height of the coke packed bed 11 was constant. 15 is a coke inlet and 16 is an exhaust gas outlet. After the experiment was completed, the device was disassembled, and coke was collected from the sampling region 18 surrounded by the broken line in the figure immediately above the raceway 17 and the powder ratio of 3 mm or less (-3 mm) in particle size was measured. FIG. 5 shows the results of experiments using cokes having different cold strengths (DI) and measuring the coke powder rate. As shown in FIG. 5, when low DI coke was used, it was confirmed that the powder rate in a packed bed was high. However, even when coke with low cold strength (DI) is used, air permeability is improved by ensuring voids in the furnace through the combined use of scrap charging, so low DI coke is used in the furnace. Even when the powder rate increases, it is considered that the air permeability can be maintained.

上記実験１の結果から、スクラップを装入した場合における炉内空隙率の変化について、エルガン（Ｅｒｇｕｎ）によって提案されている下記（１）式を用いて推定した。
△Ｐ／△Ｌ＝１５０{（１一ε）2μｕ／ε3（φｄｐ）2}＋１．７５{（１一ε）ρｕ2／ε3（φｄｐ）}・・・（１）
ただし、△Ｐ：炉内の差圧（Ｐａ）、
△Ｌ：層厚（ｍ）、
ε：炉内の空隙率（−）、
μ：流体の粘度（Ｐａ・ｓ）、
ｕ：流体の速度（ｍ／ｓ）、
ρ：流体の密度（ｋｇ／ｍ3）、
φ：粒子の形状係数（−）、
ｄｐ：粒子の平均粒径（ｍ）である。 From the results of Experiment 1 above, the change in the porosity in the furnace when scrap was charged was estimated using the following formula (1) proposed by Ergun.
ΔP / ΔL = 150 {(one ε) 2 μu / ε 3 (φdp) 2 } +1.75 {(one ε) ρu 2 / ε 3 (φdp)} (1)
Where ΔP: differential pressure in the furnace (Pa)
ΔL: layer thickness (m),
ε: porosity in the furnace (−),
μ: fluid viscosity (Pa · s),
u: fluid velocity (m / s),
ρ: fluid density (kg / m 3 ),
φ: Shape factor of particle (-),
dp: average particle diameter (m) of the particles.

（１）式により推算される差圧が、実験により測定された差圧と等しくなるように、炉内の空隙率を決定した。図６に結果を示す。図６に示すように、スクラップの装入によりスクラップ比率が増加すると、炉内の空隙率εが増加することから、低ＤＩコークスの使用により炉内粉率が増加した場合でも、炉内の空隙率を維持することができると考えられる。   The porosity in the furnace was determined so that the differential pressure estimated by the equation (1) was equal to the differential pressure measured by experiment. The results are shown in FIG. As shown in FIG. 6, when the scrap ratio increases due to the introduction of scrap, the void ratio ε in the furnace increases, so even if the powder ratio in the furnace increases due to the use of low DI coke, the void in the furnace It is thought that the rate can be maintained.

上記の実験１、実験２の結果から、高ＲＤＩ焼結鉱、および、低ＤＩコークスを使用する際に、通気性を維持するのに必要な、装入鉄原料中へのスクラップの装入比率（スクラップ率）を計算すると、ＲＤＩの１％増加に対して、スクラップ装入比率を０．２２％増加させる（ＲＤＩ：＋１％→スクラップ装入比率：＋０．２２％）、またはＤＩの１％低下に対して、スクラップ装入比率を２．８４％増加させる（ＤＩ：−１％→スクラップ装入比率：＋２．８４％）必要があることになる。   From the results of Experiment 1 and Experiment 2 above, it is necessary to use the high RDI sintered ore and the low DI coke, and the scrap charging ratio into the charged iron raw material is necessary to maintain the air permeability. When the (scrap rate) is calculated, the scrap charging ratio is increased by 0.22% with respect to 1% increase of RDI (RDI: + 1% → scrap charging ratio: + 0.22%), or 1% of DI The scrap charging ratio needs to be increased by 2.84% (DI: −1% → scrap charging ratio: + 2.84%) against the decrease.

つまり、高炉操業の基準となる焼結鉱のＲＤＩより高ＲＤＩ焼結鉱を使用した場合に増加した炉差圧よりも、スクラップの装入により低減した炉差圧が大きければ、または、基準となるコークスのＤＩより低ＤＩコークスを使用した場合に増加した炉内粉率よりも、スクラップの装入により増加した空隙率が大きければ、基準となる原燃料品質時の通気性を確保できる。そのため原燃料の品質を低下させて操業を行なう場合にも適切な量のスクラップの装入により、還元材比を増加させることなく安定操業が可能となる。   In other words, if the furnace differential pressure reduced by charging the scrap is larger than the furnace differential pressure increased when using RDI sinter higher than the RDI of the sinter that becomes the standard for blast furnace operation, or If the void ratio increased by charging the scrap is larger than the in-furnace powder ratio increased when using a low-DI coke than the coke DI, the air permeability at the reference raw fuel quality can be secured. Therefore, even when the operation is performed with the quality of the raw fuel lowered, stable operation can be performed without increasing the reducing material ratio by inserting an appropriate amount of scrap.

以上のことから、炉頂から酸化鉄原料とコークスとを交互に装入する通常の操業を行なう高炉において、酸化鉄原料の少なくとも一部として焼結鉱を使用する際に、焼結鉱の還元粉化指数が基準値以上の焼結鉱を使用する際には、還元材比を増加させることなく酸化鉄原料の一部をスクラップで代替した操業とすることで、炉内の通気性を維持することが可能であること、また、強度指数が基準値以下のコークスを使用する場合には、還元材比を増加させることなく酸化鉄原料の一部をスクラップで代替することで、炉内の通気性を維持することが可能であることが分かる。   From the above, when using sintered ore as at least part of the iron oxide raw material in a blast furnace that performs normal operation of alternately charging iron oxide raw material and coke from the top of the furnace, the reduction of the sintered ore When using sintered ore with a pulverization index exceeding the standard value, maintaining the air permeability in the furnace by replacing the part of the iron oxide raw material with scrap without increasing the reducing material ratio In addition, when using coke whose strength index is lower than the standard value, by replacing part of the iron oxide raw material with scrap without increasing the reducing material ratio, It can be seen that the air permeability can be maintained.

本発明においては低還元材比操業を行なうことを目的としているため、還元材比を増加させることなく酸化鉄原料の一部をスクラップで代替する必要がある。尚、スクラップとは、金属製品の廃棄物や、金属製品の製造工程で生じる廃金属であり、金属鉄を主体とするものである。   In the present invention, since the purpose is to operate at a low reducing material ratio, it is necessary to replace a part of the iron oxide raw material with scrap without increasing the reducing material ratio. Note that the scrap is a waste of metal products or a waste metal generated in the manufacturing process of metal products, and is mainly composed of metallic iron.

また、酸化鉄原料の一部と代替したスクラップは、炉中心部に装入することが好ましい。スクラップは高炉内で降下しながらスクラップ外部からの伝熱により昇温され溶融に至ることから、高温領域に長時間滞留できる位置、つまり、高温領域が高さ方向で比較的長い炉中心部に装入することが望ましい。ここで炉中心部とは、炉口断面積を半径方向に３等分した場合の最も炉内側の領域（炉中心から炉口径の約５７％までの領域）と定義する。   Moreover, it is preferable to charge the scrap replaced with a part of the iron oxide raw material into the furnace center. As scrap descends in the blast furnace and is heated and melted by heat transfer from the outside of the scrap, it is placed in a position where it can stay for a long time in the high temperature area, that is, in the furnace center where the high temperature area is relatively long in the height direction. It is desirable to enter. Here, the furnace center is defined as the innermost region (region from the furnace center to about 57% of the diameter of the furnace) when the sectional area of the furnace port is equally divided into three.

（比較例１）内容積５０００ｍ3の高炉を用いて焼結鉱のＲＤＩおよびコークスのＤＩを変化させて操業を行った。その結果を比較例１として表１に示す。還元材比は４９５ｋｇ／ｔで操業しており、ここでは、焼結鉱ＲＤＩ：３５％、コークスＤＩ：８４％を原燃料品質の基準値とした。 (Comparative Example 1) Using a blast furnace with an internal volume of 5000 m 3 , the RDI of the sintered ore and the DI of the coke were changed. The results are shown in Table 1 as Comparative Example 1. The reducing material ratio was operated at 495 kg / t, and here, the sinter ore RDI: 35% and coke DI: 84% were used as reference values for raw fuel quality.

Figure 2008240028
（比較例２）別の比較例として、比較例１の操業条件を基準とし、基準値よりも高ＲＤＩ焼結鉱、および、低ＤＩコークスを使用した事例を示す。結果を比較例２として表１に併せて示す。この場合には、操業が不安定となり、還元材比が増加し、通気抵抗指数のＫ値（Ｋ＝（Ｐblast 2−Ｐ2）／Ｖ1.7：ただし、Ｐblast：送風圧（ｋｇ／ｃｍ2）、Ｐ：炉頂圧（ｋｇ／ｃｍ2）、Ｖ：ボッシュガス量（Ｎｍ3／ｍｉｎ））が上昇した。
Figure 2008240028
 (Comparative Example 2) As another comparative example, an example in which a high RDI sintered ore and a low DI coke are used with reference to the operation condition of Comparative Example 1 is shown. The results are also shown in Table 1 as Comparative Example 2. In this case, the operation becomes unstable, the reducing material ratio increases, and the K value of the airflow resistance index (K = (P blast 2 -P 2 ) / V 1.7 : where P blast : blowing pressure (kg / cm 2 ), P: furnace top pressure (kg / cm 2 ), V: Bosch gas amount (Nm 3 / min)) increased.

（本発明例）次に本発明例として、基準値よりも高ＲＤＩ焼結鉱、低ＤＩコークスを使用する操業（比較例２）に対して本発明を適用してスクラップと焼結鉱を３．５ｍａｓｓ％置換して装入した。結果を本発明例として表１に併せて示す。この場合には、基準値と比較してＲＤＩが３％高い焼結鉱、および、ＤＩが１％低いコークスを使用し、還元材比は基準と同じ４９５ｋｇ／ｔであるにもかかわらず、Ｋ値は基準となる操業（比較例１）と同レベルにまで減少した。   (Example of the present invention) Next, as an example of the present invention, the present invention was applied to an operation (Comparative Example 2) using higher RDI sintered ore and lower DI coke than the reference value, and scrap and sintered ore were reduced to 3 The battery was charged with a replacement of 5 mass%. The results are also shown in Table 1 as examples of the present invention. In this case, a sinter with RDI 3% higher than the reference value and coke with DI 1% lower are used, and the reducing material ratio is 495 kg / t, which is the same as the reference, but K The value decreased to the same level as the standard operation (Comparative Example 1).

これにより本発明を適用することで、還元材比を増加させることなく、原燃料品質を基準値より緩和可能であることが確認された。   As a result, it was confirmed that by applying the present invention, the raw fuel quality can be relaxed from the reference value without increasing the reducing material ratio.

実験１に用いる荷重軟化試験装置の概略図。Schematic of the load softening test apparatus used for Experiment 1. FIG. 荷重軟化試験によるスクラップ装入比率と炉差圧（ΔＰ）の関係を示すグラフ。The graph which shows the relationship between the scrap charging ratio by a load softening test, and a furnace differential pressure ((DELTA) P). 荷重軟化試験による焼結鉱の還元粉化指数（ＲＤＩ）と炉差圧（ΔＰ）の関係を示すグラフ。The graph which shows the relationship between the reduced powdering index (RDI) of a sintered ore by a load softening test, and a furnace differential pressure ((DELTA) P). 実験２に用いる高炉の羽口からレースウェイを模擬した燃焼試験装置の概略図。FIG. 3 is a schematic diagram of a combustion test apparatus that simulates a raceway from the tuyere of a blast furnace used in Experiment 2; 燃焼試験によるコークスの冷間強度（ＤＩ）と炉内粉率の関係を示すグラフ。The graph which shows the relationship between the cold strength (DI) of the coke by a combustion test, and the powder rate in a furnace. 荷重軟化試験によるスクラップ装入比率と空隙率（ε）の関係を示すグラフ。The graph which shows the relationship between the scrap charging ratio and porosity ((epsilon)) by a load softening test.

符号の説明Explanation of symbols

１ 黒鉛るつぼ
２ 加熱炉
３ ＣＯ、ＣＯ2、Ｎ2ガス
４ 排ガス
１０ 燃焼試験容器
１１ コークス充填層
１２ ブローパイプ
１３ 熱風
１４ 微粉炭
１５ コークス投入口
１６ 排ガス排出口
１７ レースウェイ
１８ サンプリング領域 1 Graphite crucible 2 Heating furnace 3 CO, CO 2 , N 2 gas 4 Exhaust gas 10 Combustion test vessel 11 Coke packed bed 12 Blow pipe 13 Hot air 14 Pulverized coal 15 Coke inlet 16 Exhaust gas outlet 17 Raceway 18 Sampling area

Claims (3)

炉頂から酸化鉄原料とコークスとを交互に装入する高炉操業であって、前記酸化鉄原料の少なくとも一部として焼結鉱を使用する際に、前記焼結鉱の還元粉化指数が基準値以上の場合には、還元材比を増加させることなく前記酸化鉄原料の一部をスクラップで代替することで、炉内の通気性を維持することを特徴とする高炉操業方法。   It is a blast furnace operation in which iron oxide raw material and coke are alternately charged from the top of the furnace, and when using the sintered ore as at least a part of the iron oxide raw material, the reduced powder index of the sintered ore is a standard A blast furnace operating method characterized by maintaining air permeability in the furnace by replacing a part of the iron oxide raw material with scrap without increasing the reducing material ratio when the value is higher than the value. 炉頂から酸化鉄原料とコークスとを交互に装入する高炉操業において、前記コークスの強度指数が基準値以下の場合には、還元材比を増加させることなく前記酸化鉄原料の一部をスクラップで代替することで、炉内の通気性を維持することを特徴とする高炉操業方法。   In blast furnace operation where iron oxide raw material and coke are alternately charged from the top of the furnace, if the strength index of the coke is below a reference value, a portion of the iron oxide raw material is scrapped without increasing the reducing material ratio. A blast furnace operating method characterized by maintaining air permeability in the furnace by substituting with スクラップを炉中心部に装入することを特徴とする請求項１または請求項２に記載の高炉操業方法。   The blast furnace operating method according to claim 1 or 2, wherein scrap is charged into a furnace center.
JP2007079462A 2007-03-26 2007-03-26 Method for operating blast furnace Pending JP2008240028A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113791104A (en) * 2021-08-18 2021-12-14 首钢集团有限公司 Method for detecting influence of particle size of iron-containing furnace burden on pressure difference of blast furnace blocky belt
CN114606354A (en) * 2022-03-31 2022-06-10 鞍钢股份有限公司 Method for analyzing tuyere raceway height by means of hearth sampling
CN114752717A (en) * 2022-03-31 2022-07-15 鞍钢股份有限公司 Method for analyzing tuyere raceway width by means of hearth sampling
CN114908202A (en) * 2022-04-27 2022-08-16 鞍钢股份有限公司 Method for calculating size of active area of integral hearth by utilizing hearth sampling means

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113791104A (en) * 2021-08-18 2021-12-14 首钢集团有限公司 Method for detecting influence of particle size of iron-containing furnace burden on pressure difference of blast furnace blocky belt
CN114606354A (en) * 2022-03-31 2022-06-10 鞍钢股份有限公司 Method for analyzing tuyere raceway height by means of hearth sampling
CN114752717A (en) * 2022-03-31 2022-07-15 鞍钢股份有限公司 Method for analyzing tuyere raceway width by means of hearth sampling
CN114606354B (en) * 2022-03-31 2023-03-17 鞍钢股份有限公司 Method for analyzing tuyere raceway height by means of hearth sampling
CN114752717B (en) * 2022-03-31 2023-03-17 鞍钢股份有限公司 Method for analyzing tuyere raceway width by means of hearth sampling
CN114908202A (en) * 2022-04-27 2022-08-16 鞍钢股份有限公司 Method for calculating size of active area of integral hearth by utilizing hearth sampling means
CN114908202B (en) * 2022-04-27 2023-03-17 鞍钢股份有限公司 Method for calculating size of active area of integral hearth by utilizing hearth sampling means

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