JP2000226608A - Operation of blast furnace - Google Patents
Operation of blast furnaceInfo
- Publication number
- JP2000226608A JP2000226608A JP11026318A JP2631899A JP2000226608A JP 2000226608 A JP2000226608 A JP 2000226608A JP 11026318 A JP11026318 A JP 11026318A JP 2631899 A JP2631899 A JP 2631899A JP 2000226608 A JP2000226608 A JP 2000226608A
- Authority
- JP
- Japan
- Prior art keywords
- blast furnace
- reduction rate
- raw material
- gas
- fuel ratio
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Manufacture Of Iron (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、高炉装入原料の予
備還元率を変化させることにより、高炉発生ガスの発熱
量を制御する高炉操業方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blast furnace operating method for controlling a calorific value of a gas generated from a blast furnace by changing a pre-reduction rate of a blast furnace raw material.
【0002】[0002]
【従来の技術】最近の社会的ニーズであるCO2削減
は、鉄鋼業において高炉発生ガス量の低減、すなわち高
炉の燃料比低減を迫るものである。しかし、高炉発生ガ
スは製鉄所内で加熱炉等の燃料として使用される場合が
多く、このような観点からすれば、燃料比低減は高炉発
生ガスの発熱量(潜熱)低下に繋がるので好ましくな
い。そこで、高炉燃料比の変動に拘わらず高炉発生ガス
の発熱量を維持したり、高炉の燃料比を一定に維持した
まま高炉発生ガスの発熱量を高くするような技術が必要
となる。2. Description of the Related Art Reduction of CO 2, which is a recent social need, imposes a reduction in the amount of gas generated in a blast furnace, that is, a reduction in the fuel ratio of a blast furnace in the steel industry. However, the blast furnace generated gas is often used as a fuel for a heating furnace or the like in an ironworks, and from such a viewpoint, a decrease in the fuel ratio is not preferable because it leads to a decrease in the calorific value (latent heat) of the blast furnace generated gas. Therefore, there is a need for a technique for maintaining the calorific value of the blast furnace generated gas irrespective of the fluctuation of the blast furnace fuel ratio or increasing the calorific value of the blast furnace generated gas while maintaining the fuel ratio of the blast furnace constant.
【0003】[0003]
【解決すべき課題】ところで、従来の高炉操業では高炉
発生ガスの発熱量は燃料比と相関があり、燃料比が高け
れば高炉発生ガスの発熱量も高くなり、また、燃料比が
低ければ発熱量も低くなり、高炉燃料比に依存せずに高
炉発生ガスの発熱量を有効に制御することは未だなされ
ていない。In the conventional blast furnace operation, the calorific value of the gas generated from the blast furnace has a correlation with the fuel ratio. The higher the fuel ratio, the higher the calorific value of the gas generated by the blast furnace, and the lower the fuel ratio, the higher the calorific value. The amount is also low, and effective control of the calorific value of the gas generated from the blast furnace without depending on the fuel ratio of the blast furnace has not yet been performed.
【0004】本発明はかかる事情に鑑みてなされたもの
であって、高炉燃料比に依存せずに高炉発生ガスの発熱
量を有効に制御することができる高炉操業方法を提供す
ることを目的とする。The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a blast furnace operating method capable of effectively controlling a calorific value of a blast furnace generated gas without depending on a blast furnace fuel ratio. I do.
【0005】[0005]
【課題を解決する手段】発明者らは、上記課題を解決す
べく、総括物質・熱収支を基にしたリスト線図を種々検
討した結果、高炉装入原料の予備還元率(鉱石の酸化
度)を変化させることにより、高炉の燃料比に依存せず
に高炉発生ガスの発熱量を制御することができることを
見出した。Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have examined various wrist diagrams based on the overall material and heat balance, and found that the preliminary reduction rate of the blast furnace feedstock (ore oxidation degree) ), It was found that the calorific value of the gas generated from the blast furnace can be controlled without depending on the fuel ratio of the blast furnace.
【0006】具体的には、この総括物質・熱収支を基に
したリスト線図の検討の結果、例えば、高炉へ装入する
鉄鉱石の予備還元率を20%以上30%未満(酸化鉄の
還元前の状態をFe2O3とした時のFeOまでの予備
還元状態)とすれば、高炉の燃料比を一定にしたまま高
炉発生ガスの発熱量を鉄鉱石の予備還元率にほぼ比例し
て変化させることが可能であり、また、高炉へ装入する
鉄鉱石の予備還元率を30%以上70%未満とすれば、
高炉発生ガスの発熱量を一定に維持したまま燃料比を変
化させることが可能であるとの知見を得て本発明を完成
するに至った。More specifically, as a result of studying a wrist diagram based on the overall material and heat balance, for example, the preliminary reduction rate of iron ore charged into the blast furnace is 20% or more and less than 30% (iron oxide If the pre-reduction state is a pre-reduction state up to FeO when Fe 2 O 3 is assumed), the calorific value of the gas generated from the blast furnace is substantially proportional to the pre-reduction rate of the iron ore while keeping the fuel ratio of the blast furnace constant. If the pre-reduction rate of the iron ore charged into the blast furnace is 30% or more and less than 70%,
The inventors have found that it is possible to change the fuel ratio while keeping the calorific value of the blast furnace generated gas constant, and have completed the present invention.
【0007】すなわち、第1の発明は、高炉装入原料の
予備還元率を20%以上70%未満となるように調整し
て、高炉発生ガスの発熱量を制御することを特徴とする
高炉操業方法である。[0007] That is, the first invention is characterized in that the blast furnace operation is characterized by adjusting the pre-reduction rate of the blast furnace raw material to be at least 20% and less than 70% to control the calorific value of the blast furnace generated gas. Is the way.
【0008】第2の発明は、高炉装入原料の予備還元率
を20%以上30%未満となるように調整して、高炉の
燃料比を略一定に維持しながら高炉発生ガスの発熱量を
制御することを特徴とする高炉操業方法である。According to a second aspect of the present invention, the calorific value of the gas generated from the blast furnace is adjusted while maintaining the fuel ratio of the blast furnace substantially constant by adjusting the pre-reduction rate of the raw material charged in the blast furnace to 20% or more and less than 30%. It is a blast furnace operating method characterized by controlling.
【0009】第3の発明は、高炉装入原料の予備還元率
を30%以上70%未満となるように調整して、高炉燃
料比の変動に拘わらず高炉発生ガスの発熱量を略一定に
制御することを特徴とする高炉操業方法である。The third invention adjusts the pre-reduction rate of the blast furnace raw material to be 30% or more and less than 70% to keep the calorific value of the blast furnace generated gas substantially constant irrespective of fluctuations in the blast furnace fuel ratio. It is a blast furnace operating method characterized by controlling.
【0010】第4の発明は、高炉装入原料の予備還元率
を30%以上70%未満となるように調整するととも
に、高炉装入原料の一部に高結晶水鉱石を使用すること
を特徴とする高炉操業方法である。これにより、高炉装
入原料の予備還元率が30%を超えた場合に生ずる炉頂
ガス温度の上昇を抑制することができる。A fourth aspect of the invention is characterized in that the preliminary reduction rate of the blast furnace charge is adjusted to be 30% or more and less than 70%, and that high crystalline water ore is used as a part of the blast furnace charge. Is the blast furnace operating method. As a result, it is possible to suppress a rise in the furnace top gas temperature that occurs when the preliminary reduction rate of the blast furnace raw material exceeds 30%.
【0011】第5の発明は、第1の発明ないし第4の発
明のいずれかにおいて、高炉装入原料の予備還元率の重
量平均値を調整するにあたり、高炉装入原料の一部に少
なくとも還元率が20%以上70%未満の範囲に予備還
元された焼結鉱を配合することを特徴とする高炉操業方
法である。なお、高炉装入原料の予備還元率は、通常焼
結鉱、予備還元焼結鉱、鉄スクラップ等の高炉装入原料
を構成する個々の原料の還元率の加重平均値として求め
た平均予備還元率として求めることができる。A fifth aspect of the present invention is the method according to any one of the first to fourth aspects, wherein at least a part of the blast furnace charge is reduced by adjusting the weight average of the preliminary reduction rate of the blast furnace charge. A blast furnace operating method characterized in that a pre-reduced sintered ore is blended in a ratio of 20% or more to less than 70%. The preliminary reduction rate of the blast furnace raw material is the average preliminary reduction obtained as a weighted average value of the reduction rates of the individual raw materials constituting the blast furnace raw material such as ordinary sinter, preliminary reduced sinter, and iron scrap. It can be obtained as a rate.
【0012】[0012]
【発明の実施の形態】本発明は、高炉装入原料の予備還
元率を20%以上70%未満となるように調整して、高
炉発生ガスの発熱量を制御するものであるが、これは発
明者らが総括物質・熱収支を基にしたリスト線図から理
論的に見出した知見に基づくものである。この知見、す
なわち、高炉装入原料である鉄鉱石の予備還元率(酸化
度)を変化させることにより、高炉の燃料比に依存せず
に高炉発生ガスの発熱量を制御し得るとの知見につい
て、図面に基づいて説明する。図1は高炉内部のガス温
度分布を示すグラフ、図2は酸化鉄の還元平衡と実際の
炉内ガス組成と酸化鉄酸化度の関係を示すグラフであ
る。DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the calorific value of blast furnace generated gas is controlled by adjusting the preliminary reduction rate of the blast furnace raw material to be 20% or more and less than 70%. It is based on the knowledge that the inventors theoretically found from a list diagram based on the overall material and heat balance. Regarding this finding, that is, by changing the pre-reduction rate (degree of oxidation) of iron ore, which is a blast furnace charge, it is possible to control the calorific value of blast furnace generated gas without depending on the fuel ratio of the blast furnace. This will be described with reference to the drawings. FIG. 1 is a graph showing the gas temperature distribution inside the blast furnace, and FIG. 2 is a graph showing the relationship between the reduction equilibrium of iron oxide, the actual gas composition in the furnace, and the degree of iron oxide oxidation.
【0013】図1では、高炉内部のガス温度は炉頂部で
約150〜200℃、羽口先で2000〜2400℃で
ある。また、シャフト部にはいわゆる熱保存帯と称する
ほぼ1000℃一定の温度領域が存在する。この熱保存
帯では酸化鉄はFeO〜Fe還元平衡から僅かにずれた
ガス組成および還元段階で存在する。図2において、上
段の横軸は高炉のガスの酸化度(換言すれば、炭素原子
に対する酸素原子比O/C)である。ガスの酸化度は高
炉下部でガス組成がCOのみの場合は1であり、ガスが
酸化鉄を還元しながら上部に移行して最終的に全量CO
2(+N2)となった場合は2である。一方縦軸は鉄原
子に対する酸素原子比(O/Fe)を示す。装入時の最
も酸化度の高い状態がFe2O3(酸化度=1.5)で
あり、高炉内で順次還元が進むにつれ、Fe3O4(酸
化度=1.33)、FeO(酸化度=1.05)となり
最終的には金属鉄(酸化度=0)になる。また、これを
還元率で表せばFe2O3(還元率=0%)、Fe3O
4(還元率=11.3%)、FeO(還元率=30
%)、金属鉄(還元率=100%)である。In FIG. 1, the gas temperature inside the blast furnace is about 150 to 200 ° C. at the top of the furnace and 2000 to 2400 ° C. at the tuyere. Further, the shaft portion has a so-called heat preservation zone, which is a constant temperature region of approximately 1000 ° C. In this heat preservation zone, iron oxide is present in the gas composition and reduction stage slightly deviating from the FeO-Fe reduction equilibrium. In FIG. 2, the horizontal axis in the upper part indicates the degree of oxidation of the gas in the blast furnace (in other words, the ratio of oxygen atoms to carbon atoms, O / C). The degree of oxidation of the gas is 1 when the gas composition is only CO in the lower part of the blast furnace, and the gas moves to the upper part while reducing iron oxide, and finally the total amount of CO is reduced.
2 when it is 2 (+ N 2 ). On the other hand, the vertical axis indicates the oxygen atom ratio to the iron atom (O / Fe). The state with the highest degree of oxidation at the time of charging is Fe 2 O 3 (degree of oxidation = 1.5). As the reduction proceeds sequentially in the blast furnace, Fe 3 O 4 (degree of oxidation = 1.33), FeO ( The oxidation degree becomes 1.05), and finally becomes metallic iron (oxidation degree = 0). In addition, if this is represented by a reduction rate, Fe 2 O 3 (reduction rate = 0%), Fe 3 O
4 (reduction rate = 11.3%), FeO (reduction rate = 30)
%) And metallic iron (reduction rate = 100%).
【0014】図2の下段は酸化鉄のCOによる還元平衡
図である。横軸は上述と同様ガスの酸化度を表し、縦軸
は還元平衡温度を表す。図1より熱保存帯の温度を10
00℃とした場合、図2の下段よりこの温度におけるF
e〜FeO還元平衡時のガス酸化度(O/C)が求めら
れる。鉱石(FeO)の酸化度が1.05であることか
ら図2上段のW点が求まる。The lower part of FIG. 2 is an equilibrium diagram of the reduction of iron oxide by CO. The horizontal axis represents the degree of oxidation of the gas as described above, and the vertical axis represents the reduction equilibrium temperature. According to FIG.
When the temperature is set to 00 ° C., the F at this temperature is lower than the lower stage in FIG.
The degree of gas oxidation (O / C) at the time of e-FeO reduction equilibrium is determined. Since the degree of oxidation of ore (FeO) is 1.05, the point W in the upper part of FIG. 2 is obtained.
【0015】一方、酸化度1.5の鉱石(Fe2O3)
を炉頂より装入した場合、直線PT−PB(以下操作線
と称す)に沿って鉱石の酸化度及びガスの酸化度が変化
する。高炉の燃料比はこの直線の勾配(C/Fe)で決
定される。高炉の操業が理想的に行われ、還元平衡に到
達している場合には、この直線はW点に接し、燃料比は
最小値をとる。しかし、実際の高炉では酸化鉄の還元は
平衡よりずれるため操作線はW点を通らず、例えばP1
点を通る。ここで直線P0−Wと直線P0−P 1の長さ
の比(P0−W)/(P0−P1)は高炉の還元平衡到
達度を表し、シャフト効率と称されるものである。通
常、高炉のシャフト効率は0.90〜0.95程度であ
る。On the other hand, an ore having an oxidation degree of 1.5 (Fe2O3)
Is charged from the furnace top, a straight line PT-PB (hereinafter referred to as an operation line)
Along with the degree of oxidation of ore and gas
I do. The fuel ratio of the blast furnace is determined by the gradient of this straight line (C / Fe).
Is determined. Operation of the blast furnace is ideal, and reduction equilibrium is reached.
If so, this line touches point W and the fuel ratio is
Take the minimum value. However, in actual blast furnaces, iron oxide reduction
The operation line does not pass through the point W because it deviates from the equilibrium.
Pass through a point. Where the straight line P0−W and straight line P0−P 1Length of
Ratio (P0−W) / (P0−P1) Is the reduction equilibrium of the blast furnace
It indicates the degree of achievement and is called shaft efficiency. Through
The shaft efficiency of a blast furnace is usually 0.90 to 0.95.
You.
【0016】さて、第2の発明のように高炉装入原料の
予備還元率を20%以上、30%未満とした場合、高炉
装入原料の酸化度は1.5より低いから、図2のPTに
代わってPT’’になる。これによりガス組成(酸化
度)も低下し、その結果高炉発生ガスの発熱量が上昇す
る。ただし、この場合は操作線の勾配は変化しないので
燃料比は原則的には変化しない。すなわち、高炉の燃料
比を略一定に維持しながら高炉発生ガスの発熱量を制御
することが可能である。When the preliminary reduction rate of the blast furnace charge is set to 20% or more and less than 30% as in the second invention, the oxidation degree of the blast furnace charge is lower than 1.5. It becomes P T '' on behalf of the P T. As a result, the gas composition (oxidation degree) also decreases, and as a result, the calorific value of the blast furnace generated gas increases. However, in this case, since the gradient of the operation line does not change, the fuel ratio does not change in principle. That is, it is possible to control the calorific value of the blast furnace generated gas while maintaining the fuel ratio of the blast furnace substantially constant.
【0017】また、第3の発明のように高炉装入原料の
予備還元率が30%を超える場合には、W点の縦座標は
1.05より低いW’点に移行する。シャフト効率一定
と仮定すると、操作線はシャフト効率(P0−P1’/
P0−W’)が一定となるP 1’点を通ることになり、
その結果操作線の勾配は小さくなり燃料比は低下する。
ただし、この場合はガスの酸化度の低下はないので高炉
発生ガスの発熱量は変化しないと推察される。すなわ
ち、高炉燃料比の変動に拘わらず高炉発生ガスの発熱量
を略一定に制御することが可能である。Further, as in the third invention, the blast furnace charge
If the reserve rate exceeds 30%, the ordinate of point W is
It moves to the W 'point lower than 1.05. Constant shaft efficiency
Assuming that the operating line is the shaft efficiency (P0−P1’/
P0-W ') is constant 1’Point,
As a result, the slope of the operation line becomes smaller, and the fuel ratio decreases.
However, in this case, there is no decrease in the degree of oxidation of the gas.
It is assumed that the calorific value of the generated gas does not change. Sand
That is, the calorific value of the gas generated from the blast furnace regardless of the fluctuation of the blast furnace fuel ratio
Can be controlled to be substantially constant.
【0018】すなわち、高炉装入原料の予備還元率が3
0%未満(FeO還元段階まで)ではその予備還元率に
応じて高炉発生ガスの酸化度が低下し、その結果高炉発
生ガスの発熱量が向上する。なお、この場合高炉の燃料
比低減、その結果としての高炉発生ガス量(=炭酸ガス
発生量)の削減はできないが、高炉発生ガスを製鉄所内
で加熱炉等の燃料として使用する場合には、高炉発生ガ
スの発熱量が向上するため製鉄所の総エネルギー消費量
を削減することが可能となる。また、予備還元率が20
%未満では高炉発生ガス発熱量の上昇効果が少ない。That is, the preliminary reduction rate of the blast furnace raw material is 3
If it is less than 0% (up to the FeO reduction stage), the degree of oxidation of the blast furnace generated gas decreases in accordance with the preliminary reduction rate, and as a result, the calorific value of the blast furnace generated gas increases. In this case, it is not possible to reduce the fuel ratio of the blast furnace, and consequently the amount of blast furnace generated gas (= carbon dioxide gas generation), but if the blast furnace generated gas is used as fuel for heating furnaces in steelworks, Since the calorific value of the gas generated from the blast furnace is improved, the total energy consumption of the steelworks can be reduced. In addition, the preliminary reduction rate is 20
%, The effect of increasing the calorific value of the blast furnace generated gas is small.
【0019】一方、高炉装入原料の予備還元率が30%
以上(FeOと一部金属鉄が存在する還元段階)では予
備還元率に応じ高炉の燃料比の低減、およびその結果と
して高炉発生ガス量(=炭酸ガス発生量)の削減が可能
となる。ただし、この場合は高炉発生ガスの酸化度低下
(=発熱量の上昇)は期待できない。なお、高炉装入原
料の予備還元率は、還元率が100%に近い鉄スクラッ
プ等の割合を高くすることにより、理論的には100%
に近い値にすることは可能である。しかし、実操業にお
いては、予備還元率が30%以上になると炉頂温度が上
昇し、その低下対策が必要となるが、予備還元率が70
%以上では現状の対策では炉頂温度の上昇を抑えられな
い。そこで、本発明では予備還元率を70%未満として
いる。On the other hand, the preliminary reduction rate of the blast furnace raw material is 30%.
In the above (reduction stage in which FeO and some metallic iron are present), the fuel ratio of the blast furnace can be reduced according to the preliminary reduction rate, and as a result, the amount of gas generated from the blast furnace (= carbon dioxide gas generation amount) can be reduced. However, in this case, a decrease in the degree of oxidation of the blast furnace generated gas (= an increase in the calorific value) cannot be expected. The preliminary reduction rate of the blast furnace raw material is theoretically 100% by increasing the proportion of iron scrap or the like whose reduction rate is close to 100%.
Is possible. However, in the actual operation, when the preliminary reduction rate becomes 30% or more, the furnace top temperature rises, and it is necessary to take measures to decrease the furnace top temperature.
% Or more, the current measures cannot suppress the rise in furnace top temperature. Therefore, in the present invention, the preliminary reduction rate is set to less than 70%.
【0020】次に、本発明において高炉装入原料の予備
還元率を所定の範囲に調整する方法について説明する。
通常の高炉装入原料である焼結鉱ではFeOが5wt.
%程度、ペレットでは1wt.%程度であるが、Feは
ほとんどFe2O3の状態にあるので酸化度は1.5に
近く、高炉装入原料全体の予備還元率は高々2%程度で
ある。したがって、本願発明の予備還元率の範囲に調整
するためには、金属鉄(還元率=100%)に近い鉄ス
クラップ、還元鉄のほか、本発明者らが特願平10−3
69818号で詳細にその製造方法について記載した予
備還元焼結鉱を適宜混合配合して調整すれば良い。Next, a method of adjusting the pre-reduction rate of the blast furnace raw material to a predetermined range in the present invention will be described.
In a sintered ore, which is a normal blast furnace charge, FeO is 5 wt.
%, About 1 wt. %, But since Fe is almost in the state of Fe 2 O 3 , the degree of oxidation is close to 1.5, and the preliminary reduction rate of the entire blast furnace raw material is at most about 2%. Therefore, in order to adjust to the range of the preliminary reduction rate of the present invention, in addition to iron scrap and reduced iron close to metallic iron (reduction rate = 100%), the present inventors have disclosed in Japanese Patent Application No. 10-3.
What is necessary is just to mix and mix the pre-reduced sinters described in detail in US Pat.
【0021】特願平10−369818号は、無端移動
グレート式焼結機で焼成して焼結鉱を製造するにあた
り、少なくとも、配合原料中のSiO2含有量を6w
t.%以下に調整する工程と、前記配合原料に粒子径が
1mm〜10mmに調整された固体燃料(A)を所定量
混合して造粒物とする1次造粒工程と、前記造粒物に粒
子径が5mm以下に調整された固体燃料(B)の所定量
を混合して造粒し、固体燃料(B)により被覆された擬
似粒子とする2次造粒工程とを実施して、予備還元率が
20%以上30%未満または30%以上90%未満の予
備還元焼結鉱を得るものである。そして、固体燃料の割
合を適度なものとする観点からは、予備還元率が70%
以下が好ましいとしている。したがって、高炉装入原料
の予備還元率の重量平均値を調整するにあたり、高炉装
入原料の少なくとも一部に還元率が20%以上70%未
満の範囲に予備還元された焼結鉱を配合することが好ま
しい。Japanese Patent Application No. 10-369818 discloses that when sintering is produced by firing with an endless moving grate type sintering machine, at least the SiO 2 content in the compounding raw material is 6 watts.
t. %, A primary granulation step of mixing a predetermined amount of the solid fuel (A) having a particle diameter adjusted to 1 mm to 10 mm with the compounded raw material to form a granulated product, A secondary granulation step of mixing and granulating a predetermined amount of the solid fuel (B) whose particle diameter has been adjusted to 5 mm or less to form pseudo-particles coated with the solid fuel (B) is carried out. A prereduction sinter having a reduction ratio of 20% or more and less than 30% or 30% or more and less than 90% is obtained. From the viewpoint of making the ratio of the solid fuel appropriate, the preliminary reduction rate is 70%.
The following are preferred. Therefore, in adjusting the weight-average value of the preliminary reduction rate of the blast furnace charge, at least a part of the blast furnace charge is mixed with the pre-reduced sintered ore having a reduction rate of 20% or more and less than 70%. Is preferred.
【0022】この場合に、固体燃料(A)と固体燃料
(B)の重量の和の割合が4.5wt.%〜30.0w
t.%で、かつ、固体燃料(A)と固体燃料(B)の重
量の比(A)/(B)の値を0.8以上とすることが好
ましい。また、成品焼結鉱1tに対する固体燃料(A)
と固体燃料(B)の重量の和が50kg/t以上で、か
つ、固体燃料(A)と固体燃料(B)の重量の比(A)
/(B)の値を0.8以上となるように固体燃料の配合
量を調整することが好ましい。In this case, the ratio of the sum of the weights of the solid fuel (A) and the solid fuel (B) is 4.5 wt. % To 30.0w
t. %, And the value of the weight ratio (A) / (B) of the solid fuel (A) and the solid fuel (B) is preferably 0.8 or more. In addition, solid fuel (A) for 1t of product sintered ore
And the sum of the weights of the solid fuel (B) and the solid fuel (B) is 50 kg / t or more, and the ratio (A) of the weight of the solid fuel (A) to the weight of the solid fuel (B)
It is preferable to adjust the blending amount of the solid fuel so that the value of / (B) becomes 0.8 or more.
【0023】固体燃料(A)と固体燃料(B)として
は、通常、粉コークスが用いられ、例えば、予備還元率
の目標値を20%以上30%未満の範囲に設定する場
合、混合原料中の粉コークスの割合を4.5wt.%か
ら8.5wt.%の範囲で変化させて予備還元率と混合
原料中の粉コークスの割合との相関を求め、その相関に
基づいて混合原料中の粉コークスの割合を決定する。同
様に、予備還元率を30%以上70%未満の範囲に設定
する場合は、混合原料中の固体燃料の割合を8.5w
t.%から30wt.%の範囲で変化させて相関を求め
ればよい。As the solid fuel (A) and the solid fuel (B), coke breeze is usually used. For example, when the target value of the preliminary reduction rate is set in the range of 20% or more and less than 30%, Of the coke breeze of 4.5 wt. % To 8.5 wt. %, The correlation between the preliminary reduction rate and the ratio of coke breeze in the mixed raw material is determined, and the ratio of coke breeze in the mixed raw material is determined based on the correlation. Similarly, when the pre-reduction rate is set in the range of 30% or more and less than 70%, the ratio of the solid fuel in the mixed raw material is set to 8.5 w
t. % To 30 wt. The correlation may be obtained by changing the correlation in the range of%.
【0024】添加する粉コークス量は、混合原科に対す
る割合であるコークス比で表してもよく、また、焼結生
産量1トン当たりのコークス原単位で表してもよい。以
下の関係式を利用して、コークス比とコークス原単位の
間で換算が可能である。 コークス原単位(kg/t)={コークス比(%)×
(新原料使用量(kg/t)+返鉱使用量(kg/
t))}/(新原料使用量(kg/t)×焼結歩留
(%))×1000The amount of coke breeze to be added may be represented by a coke ratio which is a ratio to a mixed raw material, or may be represented by a unit of coke per ton of sintering production. Using the following relational expression, conversion between the coke ratio and the coke intensity can be performed. Coke basic unit (kg / t) = {Coke ratio (%) ×
(Use of new raw materials (kg / t) + return of ore (kg / t)
t))} / (new material usage (kg / t) × sintering yield (%)) × 1000
【0025】なお、上述した還元鉄は、例えばシャフト
炉タイプのミドレックスプロセス、Hyl−IIIプロセス、
またロータリーキルンタイプではSL/RNプロセス等
で製造されるが、主に電気炉原料であって還元率は95
%以上と高いものの、成品還元鉄の強度は低く、また、
生産量も少なく、高炉原料として使用することはできる
があまり適していないので、上記特願平10−3698
18号に記載した予備還元焼結鉱を使用することが好ま
しい。The above-mentioned reduced iron is obtained, for example, by a shaft furnace type Midrex process, a Hyl-III process,
The rotary kiln type is manufactured by the SL / RN process or the like.
%, But the strength of the product reduced iron is low,
Since the production amount is small and it can be used as a raw material for blast furnace, it is not very suitable.
It is preferable to use the pre-reduced sintered ore described in No. 18.
【0026】本発明で予備還元焼結鉱の予備還元率を7
0%未満とする理由は、予備還元率を70%以上にしよ
うとすると、粉コークス等の固体燃料比率が高くなりす
ぎるため焼結過程で溶融現象が生じ、その結果ガスの偏
流により還元が阻害され、予備還元率を70%以上とす
るのが困難であるためであり、また、高還元率の焼結鉱
はヤードで保管する際に再酸化するなどの問題があるた
めである。In the present invention, the pre-reduction ratio of the pre-reduction sintered ore is 7
The reason for making the pre-reduction rate less than 0% is that if the pre-reduction rate is to be 70% or more, the solid fuel ratio such as coke breeze becomes too high, so that a melting phenomenon occurs in the sintering process, and as a result, the reduction is hindered by gas drift. This is because it is difficult to set the preliminary reduction rate to 70% or more, and there is a problem that the sintered ore having a high reduction rate is reoxidized when stored in the yard.
【0027】また、高炉装入原料の予備還元率が30%
を超えると、高炉の炉頂ガス温度が上昇して設備保守の
上限温度300℃を超えるといった新たな問題が生ずる
が、その対策として、高結晶水鉱石(ピソライト)を使
用すると、高炉シャフトの上部で結晶水の分解が生じる
際の吸熱反応により炉頂ガス温度の上昇を抑制すること
ができる。The preliminary reduction rate of the blast furnace raw material is 30%.
If the temperature exceeds the upper limit, the top gas temperature of the blast furnace rises and a new problem such as exceeding the upper limit temperature of equipment maintenance of 300 ° C. occurs. Thus, the endothermic reaction when the decomposition of the crystallization water occurs can suppress the rise in the furnace top gas temperature.
【0028】[0028]
【実施例】(第1の実施例)内容積4300m3の操業
中の高炉において、装入原料中の通常焼結鉱を予備還元
焼結鉱と一部または全部置換し、場合によっては、さら
に、一部のものについて、装入原料中のペレットおよび
塊鉱石とも一部置換して装入原料の平均予備還元率を2
0%以上30%未満(最大29.0%まで)の範囲で変
化させ、この時の高炉燃料比と高炉発生ガスの発熱量の
変化を調査した(発明例1〜4)。また、比較のため、
同様に装入原料中の通常焼結鉱を予備還元焼結鉱と一部
置換することにより装入原料の平均予備還元率を10%
以上20%未満の範囲で変化させ、この時の高炉燃料比
と高炉発生ガスの発熱量の変化も併せて調査した(比較
例1〜3)。その結果を表1に示した。EXAMPLES (First Example) In an operating blast furnace having an inner volume of 4300 m 3, a part of or all of ordinary sinter in a charged material is replaced with pre-reduced sinter, and in some cases, further sinter is added. , Some of the pellets and lump ore in the charge were partially replaced to reduce the average preliminary reduction rate of the charge to 2
Changes were made in the range of 0% or more and less than 30% (up to 29.0%), and the changes in the blast furnace fuel ratio and the calorific value of the blast furnace generated gas at this time were investigated (Inventive Examples 1 to 4). Also, for comparison,
Similarly, the average pre-reduction rate of the raw material is reduced to 10% by partially replacing the normal sinter in the raw material with the preliminary reduced sinter.
The blast furnace fuel ratio and the change in the calorific value of the blast furnace generated gas at this time were also examined (Comparative Examples 1 to 3). The results are shown in Table 1.
【0029】また、その際の高炉の操業諸元を表3に示
したが装入原料以外の条件については極力変化させない
ようにした。なお、使用した予備還元焼結鉱は上述の特
願平10−369818号の製造方法により、平均予備
還元率をほぼ30%となるように調整したが、表1に示
すように、発明例1〜4および比較例1〜3で使用した
予備還元焼結鉱の予備還元率の値に若干ばらつきがあ
る。The operating specifications of the blast furnace at that time are shown in Table 3, but conditions other than the charged raw materials were not changed as much as possible. The preliminary reduced sinter used was adjusted to have an average preliminary reduction ratio of about 30% by the production method of Japanese Patent Application No. 10-369818, as shown in Table 1. The values of the pre-reduction ratios of the pre-reduction sintered ores used in Comparative Examples 1 to 4 and Comparative Examples 1 to 3 slightly vary.
【0030】表1に示すように、装入原料の平均予備還
元率が20%以上30%未満である発明例1〜4の場
合、予備還元率にほぼ比例して高炉発生ガスの発熱量が
上昇することがわかる。これに対して、平均予備還元率
が20%未満である比較例1〜3の場合には、装入原料
の予備還元率が変化しても高炉発生ガスの発熱量の変化
は小さい。また、装入原料の平均予備還元率が20%以
上30%未満の範囲で変化しても燃料比はほとんど変化
しないことも確認された。As shown in Table 1, in the case of Invention Examples 1 to 4 in which the average preliminary reduction rate of the charged raw material is 20% or more and less than 30%, the calorific value of the blast furnace generated gas is almost proportional to the preliminary reduction rate. It can be seen that it rises. On the other hand, in Comparative Examples 1 to 3 in which the average preliminary reduction rate is less than 20%, the change in the calorific value of the blast furnace generated gas is small even if the preliminary reduction rate of the charged material changes. It was also confirmed that the fuel ratio hardly changed even when the average pre-reduction rate of the charged raw material changed in the range of 20% or more and less than 30%.
【0031】したがって、本発明者らが理論的に推察し
たように、高炉装入原料の平均予備還元率を20%以上
30%未満となるように調整することにより、高炉の燃
料比を略一定に維持しながら高炉発生ガスの発熱量を制
御することが可能であることが確認された。Therefore, as the present inventors have reasoned theoretically, the fuel ratio of the blast furnace is substantially constant by adjusting the average preliminary reduction rate of the blast furnace feedstock to be 20% or more and less than 30%. It was confirmed that it was possible to control the calorific value of the blast furnace generated gas while maintaining the temperature.
【0032】次に、焼結鉱の予備還元率および装入原料
の平均予備還元率の求めかたについて説明する。一般的
には鉱石類のFe分析では、全鉄分(T.Fe)、2価
の鉄分(Fe2 +)、金属鉄分(M.Fe)が実測さ
れ、3価の鉄分(Fe3+)は全鉄分(T.Fe)から
2価の鉄分(Fe2+)および金属鉄分(M.Fe)を
差し引いて求められるが、通常焼結鉱および還元率が3
0%未満の予備還元焼結鉱では、金属鉄分(M.Fe)
は殆ど含まれないので、3価の鉄分(Fe3+)は全鉄
分(T.Fe)から2価の鉄分(Fe2+)を差し引け
ば求められる。装入原料中のペレットおよび塊鉱石には
2価の鉄分(Fe2+)は殆ど含まれないが、通常焼結
鉱には2価の鉄分(Fe2+)がFeO換算で5〜6w
t.%含まれる。通常焼結鉱および予備還元焼結鉱の予
備還元率は、それぞれ30%×(Fe2+)/(T.F
e)で求められる。したがって、装入原料の平均予備還
元率は、装入原料中の通常焼結鉱および予備還元焼結鉱
の還元率の加重平均値として求めた。Next, how to determine the preliminary reduction rate of the sinter ore and the average preliminary reduction rate of the charged material will be described. In generally Fe analysis of ores, total iron (T.Fe), 2-valent iron (Fe 2 +), metal iron (M.Fe) is actually measured, trivalent iron (Fe 3+) All It can be obtained by subtracting divalent iron (Fe 2+ ) and metallic iron (M.Fe) from iron (T.Fe).
In the pre-reduced sinter less than 0%, the metallic iron content (M.Fe)
Is almost not contained, so that the trivalent iron (Fe 3+ ) can be obtained by subtracting the divalent iron (Fe 2+ ) from the total iron (T.Fe). The pellets and lump ores charging the raw material of the divalent iron (Fe 2+) in is hardly contained, 5~6W usually sinter divalent iron (Fe 2+) is in FeO in terms
t. %included. The pre-reduction ratios of the ordinary sinter and the pre-reduction sinter are respectively 30% × (Fe 2+ ) / (TF
e). Therefore, the average preliminary reduction rate of the raw material was determined as a weighted average value of the reduction rates of the ordinary sinter and the preliminary reduced sinter in the raw material.
【0033】(第2の実施例)装入原料の平均予備還元
率を30%以上60%未満の範囲で変化させるため、還
元率がほぼ60%の予備還元焼結鉱を製造し、第1の実
施例の場合と同様に内容積4300m3の操業中の高炉
において、まず装入原料中の通常焼結鉱をこの予備還元
焼結鉱と一部置換し、さらに、一部のものについては、
装入原料中のペレットおよび塊鉱石を金属スクラップと
一部置換することにより、装入原料の平均予備還元率を
30%以上約60%まで変化させ、高炉燃料比と高炉発
生ガスの発熱量の変化を調査した(発明例11〜1
4)。その結果を表2に示す。なお、その際の高炉の操
業諸元は表3に示したとおりであり、装入原料以外の条
件については極力変化させないようにした点も第1の実
施例と同じである。(Second Embodiment) In order to change the average pre-reduction ratio of the charged raw material in the range of 30% or more and less than 60%, a pre-reduction sintered ore having a reduction ratio of approximately 60% was produced. In the blast furnace in operation with an internal volume of 4300 m 3 as in the case of the embodiment of the present invention, first, the normal sinter in the charged material is partially replaced with this pre-reduced sinter. ,
By partially replacing the pellets and lump ore in the charge with metal scrap, the average pre-reduction rate of the charge is changed from 30% to about 60%, and the blast furnace fuel ratio and the calorific value of the blast furnace generated gas are reduced. Changes were investigated (Examples 11 to 1 of the invention)
4). Table 2 shows the results. The operating parameters of the blast furnace at this time are as shown in Table 3, and the conditions other than the charged raw materials are not changed as much as possible, as in the first embodiment.
【0034】その結果、表2に示すように、装入原料の
平均予備還元率を30%以上60%未満とした発明例1
1〜14の場合、平均予備還元率にほぼ比例して高炉燃
料比が低下(約20%)したが、高炉発生ガスの発熱量
の変化はほとんどなかった。したがって、高炉装入原料
の予備還元率を30%以上60%未満となるように調整
して、高炉発生ガスの発熱量を略一定に維持しながら高
炉の燃料比を制御することが可能であることが確認され
た。As a result, as shown in Table 2, Inventive Example 1 in which the average preliminary reduction rate of the charged material was 30% or more and less than 60%.
In the case of Nos. 1 to 14, the blast furnace fuel ratio was reduced (approximately 20%) almost in proportion to the average preliminary reduction rate, but the calorific value of the blast furnace generated gas was hardly changed. Therefore, it is possible to control the fuel ratio of the blast furnace while maintaining the calorific value of the gas generated from the blast furnace substantially constant by adjusting the preliminary reduction rate of the raw material charged in the blast furnace to be 30% or more and less than 60%. It was confirmed that.
【0035】この実施例においては、高炉装入原料の予
備還元率が30%を超えると、高炉の炉頂ガス温度が上
昇して設備保守上の上限温度300℃を超えるため、そ
の対策として、装入原料中の塊鉱石の一部を結晶水含有
量が10wt.%の高結晶水鉱石(ピソライト)と置換
した。結晶水含有量が10wt.%の高結晶水鉱石を装
入原料中15%配合することで炉頂ガス温度を250℃
以下に抑制することができた。また、発明例14のよう
に高炉装入原料の平均予備還元率が50%以上と高いに
もかかわらず、装入原料中の高結晶水鉱石割合が10%
以下と少ない場合には、従来から実施されてきた炉頂散
水の併用により炉頂ガス温度を低下させた。In this embodiment, if the preliminary reduction ratio of the raw material charged in the blast furnace exceeds 30%, the temperature of the top gas of the blast furnace rises and exceeds the upper limit temperature of 300 ° C. for equipment maintenance. A part of the lump ore in the charged raw material has a water content of crystallization of 10 wt. % Of highly crystalline water ore (Pisolite). Crystal water content of 10 wt. % Of high-crystal water ore in the raw material is 15% to increase the furnace top gas temperature to 250 ° C.
The following could be suppressed. Further, although the average preliminary reduction ratio of the blast furnace charge is as high as 50% or more as in Invention Example 14, the ratio of the high crystalline water ore in the charge is 10%.
In the case of less than the following, the furnace top gas temperature was lowered by using the furnace top sprinkling which has been conventionally performed.
【0036】なお、本発明例14よりも装入原料中の鉄
スクラップを増加させることにより予備還元率をさらに
上昇させること可能であり、予備還元率が70%未満で
あれば高結晶水鉱石の併用や炉頂散水により炉頂温度を
300℃以下に抑えることができる。しかし、予備還元
率が70%以上となるとこれらの手段では炉頂温度を3
00℃以下に抑えることは難しい。It is to be noted that the pre-reduction rate can be further increased by increasing the amount of iron scrap in the charged material as compared with Example 14 of the present invention. The furnace top temperature can be suppressed to 300 ° C. or lower by the combined use or the spraying of the furnace top. However, when the pre-reduction rate becomes 70% or more, these means reduce the furnace top temperature to 3%.
It is difficult to keep the temperature below 00 ° C.
【0037】また、装入原料の予備還元率を求めるに際
し、本実施例のように還元率が30%以上の予備還元焼
結鉱では、金属鉄(M.Fe)が生成されるので、3価
の鉄分(Fe3+)は全鉄分(T.Fe)から2価の鉄
分(Fe2+)および、金属鉄分(M.Fe)を差し引
いて求める。予備還元焼結鉱の予備還元率は、30%×
(Fe2+)/(T.Fe)+100%×(M.Fe)
/(T.Fe)で求められる。装入原料の平均予備還元
率は、装入原料中の通常焼結鉱、予備還元焼結鉱および
金属スクラップの還元率の加重平均値として求めた。な
お、装入原料中の金属スクラップの予備還元率は100
%とした。In determining the pre-reduction rate of the charged raw material, in the pre-reduction sintered ore having a reduction rate of 30% or more as in this embodiment, metallic iron (M.Fe) is generated. Valent iron (Fe 3+ ) is determined by subtracting divalent iron (Fe 2+ ) and metallic iron (M.Fe) from total iron (T.Fe). The preliminary reduction rate of the preliminary reduction sinter is 30% ×
(Fe 2+ ) / (T.Fe) + 100% × (M.Fe)
/(T.Fe). The average pre-reduction rate of the raw material was determined as a weighted average of the reduction rates of the ordinary sinter, the pre-reduced sinter, and the metal scrap in the raw material. The pre-reduction rate of metal scrap in the charged raw material is 100%.
%.
【0038】[0038]
【表1】 [Table 1]
【0039】[0039]
【表2】 [Table 2]
【0040】[0040]
【表3】 [Table 3]
【0041】[0041]
【発明の効果】本発明によれば、高炉装入原料の予備還
元率を20%以上30%未満となるように調整すること
により、高炉の燃料比を略一定に維持しながら高炉発生
ガスの発熱量を制御することが可能である。また、高炉
装入原料の予備還元率を30%以上70%未満となるよ
うに調整することにより、高炉発生ガスの発熱量を略一
定に維持しながら高炉の燃料比を制御することが可能で
ある。したがって、高炉の燃料比に依存せずに、高炉発
生ガスの発熱量を制御することができる。また、高結晶
水鉱石を使用することにより、高炉装入原料の予備還元
率を30wt.%以上とした場合に生ずる炉頂ガス温度
の上昇を抑制することができる。According to the present invention, by adjusting the preliminary reduction rate of the blast furnace raw material to be 20% or more and less than 30%, the blast furnace fuel gas can be maintained at a substantially constant value while maintaining the blast furnace fuel ratio at a substantially constant value. It is possible to control the amount of heat generated. Further, by adjusting the pre-reduction rate of the blast furnace raw material to be 30% or more and less than 70%, it is possible to control the fuel ratio of the blast furnace while maintaining the calorific value of the blast furnace generated gas substantially constant. is there. Therefore, the calorific value of the blast furnace generated gas can be controlled without depending on the fuel ratio of the blast furnace. In addition, by using high-crystal water ore, the preliminary reduction rate of the blast furnace raw material is reduced to 30 wt. % Or more, it is possible to suppress a rise in the furnace top gas temperature that occurs when the temperature is set to be equal to or more than 10%.
【図1】高炉内のガス温度分布を示す図。FIG. 1 is a view showing a gas temperature distribution in a blast furnace.
【図2】酸化鉄の還元平衡と高炉内ガス酸化度と酸化鉄
酸化度の関係を示す図。FIG. 2 is a diagram showing the relationship between the reduction equilibrium of iron oxide, the degree of oxidation of gas in a blast furnace, and the degree of oxidation of iron oxide.
Claims (5)
上70%未満となるように調整して、高炉発生ガスの発
熱量を制御することを特徴とする高炉操業方法。1. A method for operating a blast furnace, wherein a preliminary reduction ratio of a raw material charged to a blast furnace is adjusted to be 20% or more and less than 70% to control a calorific value of gas generated from a blast furnace.
上30%未満となるように調整して、高炉の燃料比を略
一定に維持しながら高炉発生ガスの発熱量を制御するこ
とを特徴とする高炉操業方法。2. A method for controlling a calorific value of gas generated from a blast furnace while maintaining a fuel ratio of the blast furnace substantially constant by adjusting a pre-reduction rate of a raw material charged in the blast furnace to be 20% or more and less than 30%. Characteristic blast furnace operating method.
上70%未満となるように調整して、高炉燃料比の変動
に拘わらず高炉発生ガスの発熱量を略一定に制御するこ
とを特徴とする高炉操業方法。3. The method according to claim 1, wherein the preliminary reduction rate of the raw material charged in the blast furnace is adjusted to be 30% or more and less than 70% so that the calorific value of the gas generated from the blast furnace is controlled to be substantially constant irrespective of a change in the blast furnace fuel ratio. Characteristic blast furnace operating method.
上70%未満となるように調整するとともに、高炉装入
原料の一部に高結晶水鉱石を使用することを特徴とする
請求項3に記載の高炉操業方法。4. The method according to claim 1, wherein the preliminary reduction rate of the blast furnace charge is adjusted to be 30% or more and less than 70%, and high crystal water ore is used as a part of the blast furnace charge. 3. The blast furnace operating method according to 3.
にあたり、高炉装入原料の少なくとも一部に還元率が2
0%以上70%未満の範囲に予備還元された焼結鉱を配
合することを特徴とする請求項1ないし請求項4のいず
れか1項に記載の高炉操業方法。5. A method for adjusting the preliminary reduction rate of the blast furnace charge, wherein at least a part of the blast furnace charge has a reduction rate of 2%.
The blast furnace operating method according to any one of claims 1 to 4, wherein the pre-reduced sintered ore is blended in a range of 0% or more and less than 70%.
Priority Applications (1)
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JP02631899A JP3829516B2 (en) | 1999-02-03 | 1999-02-03 | Blast furnace operation method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP02631899A JP3829516B2 (en) | 1999-02-03 | 1999-02-03 | Blast furnace operation method |
Publications (2)
Publication Number | Publication Date |
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JP2000226608A true JP2000226608A (en) | 2000-08-15 |
JP3829516B2 JP3829516B2 (en) | 2006-10-04 |
Family
ID=12190054
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JP02631899A Expired - Lifetime JP3829516B2 (en) | 1999-02-03 | 1999-02-03 | Blast furnace operation method |
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JP (1) | JP3829516B2 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002302704A (en) * | 2001-04-04 | 2002-10-18 | Nkk Corp | Method for operating blast furnace |
JP2013133512A (en) * | 2011-12-27 | 2013-07-08 | Jfe Steel Corp | Method for producing raw material for blast furnace |
JP2013133513A (en) * | 2011-12-27 | 2013-07-08 | Jfe Steel Corp | Method for producing agglomerated ore |
JP2016050323A (en) * | 2014-08-29 | 2016-04-11 | Jfeスチール株式会社 | Blast furnace operation method |
-
1999
- 1999-02-03 JP JP02631899A patent/JP3829516B2/en not_active Expired - Lifetime
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002302704A (en) * | 2001-04-04 | 2002-10-18 | Nkk Corp | Method for operating blast furnace |
JP4724942B2 (en) * | 2001-04-04 | 2011-07-13 | Jfeスチール株式会社 | Blast furnace operation method |
JP2013133512A (en) * | 2011-12-27 | 2013-07-08 | Jfe Steel Corp | Method for producing raw material for blast furnace |
JP2013133513A (en) * | 2011-12-27 | 2013-07-08 | Jfe Steel Corp | Method for producing agglomerated ore |
JP2016050323A (en) * | 2014-08-29 | 2016-04-11 | Jfeスチール株式会社 | Blast furnace operation method |
Also Published As
Publication number | Publication date |
---|---|
JP3829516B2 (en) | 2006-10-04 |
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