WO2016051773A1 - Method for charging raw material into blast furnace - Google Patents

Method for charging raw material into blast furnace Download PDF

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Publication number
WO2016051773A1
WO2016051773A1 PCT/JP2015/004943 JP2015004943W WO2016051773A1 WO 2016051773 A1 WO2016051773 A1 WO 2016051773A1 JP 2015004943 W JP2015004943 W JP 2015004943W WO 2016051773 A1 WO2016051773 A1 WO 2016051773A1
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blast furnace
coke
raw material
outer peripheral
charging
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PCT/JP2015/004943
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French (fr)
Japanese (ja)
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寿幸 廣澤
渡壁　史朗
和平 市川
佐藤　道貴
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Ｊｆｅスチール株式会社
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Priority to JP2016551538A priority Critical patent/JP6458807B2/en
Publication of WO2016051773A1 publication Critical patent/WO2016051773A1/en

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B5/00—Making pig-iron in the blast furnace

Definitions

  • the present invention relates to a raw material charging method for a blast furnace in which the raw material is charged into the blast furnace with a turning chute.
  • a blast furnace is generally a facility for obtaining pig iron by flowing a gas from the tuyere after charging ore raw materials such as sintered ore, pellets and massive ore and coke in layers from the top of the furnace. It is. Coke and ore raw material, which are the charged raw materials, descend from the furnace top to the lower part of the furnace, and the reduction of the ore raw materials and the temperature rise of the charged raw materials occur. The ore raw material layer is gradually deformed while filling the voids due to the temperature rise and the load from above, and in the lower part of the shaft part of the blast furnace, the fusion layer has a very high ventilation resistance and hardly flows gas. It has become.
  • the raw material charging method into the blast furnace is that the ore raw material and the coke are alternately charged, and the ore raw material layer and the coke layer are alternately layered in the furnace.
  • a cohesive zone that is, an ore raw material layer having a high airflow resistance in which the ore raw material is softened and fused, and a coke slit having a relatively low airflow resistance derived from coke.
  • the air permeability of the cohesive zone greatly affects the air permeability of the entire blast furnace, thereby limiting the productivity in the blast furnace.
  • Patent Document 2 ore and coke are stored separately in different furnace top bunkers, and coke and ore are mixed and charged at the same time, so that a normal coke charging batch and a coke central charging batch are used. , And a method of forming a mixed charging batch and simultaneously performing three types of charging using the batch.
  • Patent Document 3 all ores and all cokes are used to prevent instability of the cohesive zone shape in blast furnace operation and decrease in gas utilization rate near the center of the furnace, and to improve safe operation and thermal efficiency.
  • a method is disclosed in which the components are completely mixed and then charged into the furnace.
  • JP-A-3-211210 JP 2004-107794 A Japanese Patent Publication No.59-10402
  • Patent Document 3 Although a blast furnace without a coke slit is described, a specific raw material charging method for the blast furnace is not mentioned.
  • An object of this invention is to provide the raw material charging method to the blast furnace which can reduce the ventilation resistance of a mixed layer effectively, without making a coke slit exist in a mixed layer.
  • the gist configuration of the present invention is as follows. 1.
  • Have The second step is performed such that the coke ratio in the outer peripheral mixed layer varies continuously or stepwise in the radial direction of the blast furnace, and the second step uses the mixed raw material in the outer peripheral region.
  • the inner peripheral end of the outer peripheral region is set to a position of 40% or less of the radius of the blast furnace from the axis, and the outer peripheral end of the outer peripheral region is set to a position of 80% or more of the radius of the blast furnace from the axis.
  • the central coke layer is formed at least in the central portion
  • the outer peripheral mixed layer is formed at least in the intermediate portion and the peripheral portion
  • the raw material charging start point of the outer peripheral mixed layer is the central coke layer adjacent portion, and the coke and the ore raw material and / or the mixed raw material are discharged from each furnace top bunker, mixed with the collecting hopper, and then the swivel chute 7.
  • the raw material charging method to the blast furnace according to any one of 1 to 6 above, wherein the coke ratio is changed by supplying to the blast furnace.
  • coke slits are not formed in the mixed layer, and the air flow in the blast furnace can be improved by coke dispersed in the cohesive zone.
  • the present invention uses a swirl chute into a blast furnace, ore raw materials generally used for blast furnace operations such as sintered ore, pellets, and massive ore, and coke, when charging coke into the blast furnace. This is a raw material charging method.
  • the blast furnace used in the present invention includes a bellless charging device 5 as shown in FIG.
  • the apparatus 5 includes a plurality of furnace top bunkers 2a to 2c arranged at the top of the blast furnace 1, and a collecting hopper arranged at the discharge port of each furnace top bunker to mix the raw materials discharged from the furnace top bunker 4 and a swivel chute 6 for receiving coke and mixed raw materials supplied from the collecting hopper and charging them into the blast furnace. Between the furnace top bunkers 2a to 2c and the collecting hopper 4, a flow rate adjusting gate 3 for adjusting the flow rate of the raw material from each furnace top bunker is disposed.
  • the bell-less type blast furnace is a general blast furnace for charging mixed raw materials or the like from the top of the furnace with a swirl chute 6 and flowing gas from the blast furnace tuyere to reduce iron ore to obtain pig iron. Good.
  • the inside of the blast furnace is centered in the radial direction of the blast furnace from the axial center toward the inner wall of the furnace, and an intermediate part located on the outer periphery of the center part. 14 and a peripheral portion 15 located on the outer periphery of the intermediate portion.
  • R the distance from the axis in the blast furnace to the inner wall of the furnace is defined as R, and R is defined as a dimensionless radius: 1. That is, in the present invention, the dimensionless radius in the blast furnace (or simply referred to as dimensionless radius) is a numerical value derived by the equation r0 / R, where r0 is the distance from the axis in the blast furnace.
  • the central portion 13 is a region having a dimensionless radius of 0 to 0.2 to 0.3
  • the intermediate portion is an outer periphery from the central portion and has a dimensionless radius of more than 0.2 to 0.4 to 0.
  • the area of 6 to 0.8 or less and the peripheral part is a dimensionless radius of more than 0.8 and 1 or less.
  • the present invention includes a first step of forming a central coke layer 11 by charging coke in a central region of a predetermined distance or less from an axial center in the blast furnace 1 toward the inner wall of the furnace, and a position on the outer periphery of the central coke layer. And a second step of forming an outer peripheral mixed layer 12 (hereinafter also simply referred to as “mixed layer 12”) by charging a mixed raw material of coke and ore raw material into the outer peripheral region. .
  • the plurality of furnace top bunkers 2a to 2c shown in FIG. 1 stores, for example, coke in the furnace top bunker 2a, ore raw material in the furnace top bunker 2b, and ore raw material and coke in the furnace top bunker 2c. And the mixed raw material is mixed.
  • the mixed layer 12 is formed, coke, ore raw material or mixed raw material is appropriately discharged from each furnace top bunker, mixed with a collecting hopper, and supplied to the swivel chute.
  • the coke and the ore raw material are discharged from the furnace top bunker (for example, the furnace top bunker 2a and the furnace top bunker 2b) to the collecting hopper.
  • the mixed layer 12 can be formed.
  • This first step is preferably controlled so that, for example, the turning chute 6 is controlled in a vertically tilted state at the start of charging of the coke, and thereafter a coke layer is gradually formed toward the outer peripheral side. Moreover, it is preferable to form the outer peripheral mixed layer around the central coke layer after the central coke layer is formed. This is because the central coke layer can be accurately formed by preventing the ore raw material of the mixed layer from mixing into the central coke layer. When the tip of the turning chute 6 is on the center portion 13, only the coke can be discharged from the furnace top bunker 2a, and the center coke layer 11 can be formed efficiently.
  • the central coke layer 11 preferably has a dimensionless radius in the blast furnace and is formed between 0 (center of the blast furnace) and about 0.2 to 0.3. That is, the outer periphery of the central coke layer 11 is a dimensionless radius in the blast furnace and is about 0.2 to 0.3.
  • the center coke layer adjacent portion 16 is a portion at a predetermined distance from the outer periphery of the center coke layer, and the dimensionless radius in the blast furnace: 0.3 to 0.4 from the outer periphery of the center coke layer. Say the part to the extent.
  • the outer peripheral mixed layer 12 is formed on the outer periphery of the central coke layer 11. For this reason, it is preferable to form the outer peripheral mixed layer 12 in the blast furnace in a dimensionless radius between 0.2 and 1 or less, that is, in the intermediate portion 14 and the peripheral portion 15.
  • the central coke layer 11 is formed in the central portion 13 of the blast furnace, and the air permeability of the central portion 13 can be secured by the central coke layer 11.
  • the mixed layer 12 which mixed the ore raw material and coke can be formed in the outer peripheral side of this center coke layer 11.
  • FIG. Therefore, coke slits are not formed in this mixed layer 12, and high-temperature gas can rise directly through the ore raw materials, improving air permeability and heat transfer in the blast furnace. can do.
  • the contact area between the ore raw material in the cohesive zone at the lower part of the cohesive zone and the high-temperature gas is expanded, and carburization of the ore raw material can be effectively promoted. .
  • the present invention refers to the coke ratio (coke mass / ore raw material mass) in the outer peripheral mixed layer 12 (hereinafter simply referred to as the coke ratio means the mass ratio of coke in the outer peripheral mixed layer).
  • the second step is performed continuously or stepwise with respect to the radial direction of the blast furnace.
  • the procedure for performing the second step so that the coke ratio of the mixed layer 12 varies continuously or stepwise in the radial direction of the blast furnace is specifically the amount of coke cut out from the furnace top bunker 2a in which coke is stored.
  • the coke ratio of the mixed raw material in the collecting hopper 4 is adjusted by changing the above, and this mixed raw material may be sequentially supplied to the position of a predetermined dimensionless radius in the blast furnace 6 by the turning chute 6.
  • the coke ratio is made constant with a dimensionless radius: 0.05 to 0.30, and this constant coke ratio is made stepwise different. Can do.
  • the distribution of the coke ratio in the blast furnace radial direction is that the ore raw material when the ore temperature is 1400 degrees so that the ventilation resistance in the blast furnace is about 20,000 (Pa / m 3 / min).
  • the blast furnace variation ⁇ of the shrinkage ratio (hereinafter referred to as ore 1400 degree shrinkage ratio) may be controlled to be less than 10%. ⁇ is more preferably 6% or less, and further preferably 2% or less. When ⁇ is 6%, the ventilation resistance in the blast furnace is about 19,700 (Pa / m 3 / min), and when ⁇ is 2%, the ventilation resistance in the blast furnace is 19,400 (Pa / m 3 / min). min).
  • the in-furnace variation ⁇ of the ore 1400 degrees contraction rate is determined according to a method of measuring pressure loss under conditions of temperature, gas composition and load simulating the inside of the blast furnace using a load softening test apparatus. ⁇ is obtained by subtracting the lowest value from the highest value of the 1400 degree contraction rate of the ore obtained in the central portion 13, the intermediate portion 14, and the peripheral portion 15, respectively.
  • the concentrations of carbon monoxide gas and carbon dioxide gas in the blast furnace are measured at a plurality of locations in the radial direction of the blast furnace.
  • the “gas utilization rate” at each location is defined as CO 2 / (CO 2 + CO) ⁇ 100. This value is an index indicating how much CO in the CO 2 + CO gas is used.
  • the gas utilization rate distribution can be obtained by plotting the measured values on the vertical axis and the blast furnace radial direction on the horizontal axis. Note that the CO 2 and CO concentration (volume%) used in such a formula are measured by using a device called a horizontal sonde that measures the operating gas distribution from the center to the periphery in the blast furnace.
  • FIG. 3 shows an example of a conventional gas utilization rate distribution.
  • the gas utilization rate seems to be larger in the middle part than in the central part and the peripheral part.
  • the reduction of the amount of ore present in the intermediate part has not completely progressed. Therefore, it is necessary to further increase the gas utilization rate.
  • FIG. 4 shows the ore reduction rate at the conventional blast furnace position in relation to the temperature of the raw material particles. As shown in FIG. 4, since the ore reduction rate does not increase in the intermediate part unless the temperature of the raw material particles is raised compared to the peripheral part, much of the ore present in the intermediate part is completely reduced. The tendency which is not done can be confirmed.
  • the second step can be performed by reverse tilt charging in which the mixed raw material is charged from the central region side of the outer peripheral region toward the furnace inner wall side. That is, the mixed raw material charging start point of the swirl chute is the central coke layer adjacent portion 16, and then the swirl chute 6 is sequentially moved to the furnace inner wall side while changing the coke ratio in the mixed raw material. Form.
  • the coke ratio A in the outer peripheral mixed layer of the central coke layer adjacent portion 16 and the coke ratio B in the outer peripheral mixed layer at the peripheral portion 15 are divided into the intermediate portion 14.
  • the coke ratio C is preferably in the range of 160 to 300 kg / t. Further, the coke ratios A and B are preferably smaller than the coke ratio C by about 7/10. More preferably, it is about 1/2.
  • the coke ratio A and the coke ratio B may be the same or either one may be large, but it is also preferable that the amount of B with respect to A is different by about 1.2 times.
  • the inner peripheral end of the outer peripheral region is a dimensionless radius of 0.4 or less (a position of 40% or less of the blast furnace radius), and the outer peripheral end of the outer peripheral region is a dimensionless radius of 0.8 or more (blast furnace) It is important to widen the charging range of the mixed layer as a position of 80% or more of the radius of the above. This is because, if the reverse tilt charging start position is set to the furnace center side from the inner peripheral end of the outer peripheral region, deterioration of the air permeability inside the blast furnace due to segregation of coke in the mixed layer can be prevented.
  • the starting position of reverse tilt charging is more preferably 0.25 or less in dimensionless radius. This is because the more stable deposition shape can be formed and the segregation of coke in the mixed layer can be prevented by charging from the furnace center side.
  • the starting position of reverse tilt charging is preferably about 0.2 in dimensionless radius so that the central coke layer functions effectively.
  • the end position of the reverse tilt charging is set to the furnace wall side from the outer peripheral edge of the outer peripheral region because coke in the mixed layer that easily flows to the axial center side can be deposited on the furnace wall side. This is because deterioration of the air permeability inside the blast furnace due to segregation of coke can be prevented.
  • the end position of reverse tilt charging may be a dimensionless radius of 1, but is preferably about 0.95 from the viewpoint of equipment efficiency. From the end of reverse tilt charging to the inner wall of the furnace, only the coke layer may be used, but the thickness of the coke layer, the ore layer, and the mixed layer was appropriately adjusted according to the particle size of the raw material if it is possible to ensure air permeability. Things can be used.
  • a central coke layer can be formed in the central area of the blast furnace, and the central coke layer can ensure air permeability in the central area. Therefore, in the present invention, even if the coke slit is not formed in the outer peripheral mixed layer, the high temperature gas can directly pass between the ore raw materials and rise, thereby improving air permeability and heat transfer. .
  • FIG. 2 shows the results of the following actual machine test. A coke layer was formed in the central region in the furnace, and then a mixed layer was formed in the outer peripheral region by reverse tilt charging. Various charging ranges were mixed and the mixing yield in each case was determined.
  • ⁇ r indicates a range in which the mixed raw material is charged, that is, a formation range of the outer peripheral mixed layer.
  • ⁇ r means r2-r1
  • the horizontal axis is (r2-r1 ) / R.
  • the mixed yield can be obtained by the following equation.
  • Mixing yield (%) (Average input amount- ⁇ mixing amount) / Average input amount x 100
  • the average charging amount represents the charging amount (% by mass) when charging with the charging chute
  • the ⁇ mixing amount represents a standard deviation within ⁇ r obtained from the mixing amount of coke at each point of the charging point.
  • the amount of coke charged for forming the central coke layer is preferably in the range of 5 to 25% by mass of the amount of coke charged per charge. This is because it is possible to prevent the coke in the mixed layer from flowing into the central region (referred to as the central flow).
  • the lower limit ratio of the amount of coke charged per charge is more preferably 15% by mass. This is because the central flow can be maintained and a stable mixed layer can be formed.
  • 1 charge in this invention means the action which performs the said 1st process and the said 2nd process once.
  • a coke dedicated chute (not shown) for charging coke into the central region of the blast furnace is provided outside the swivel region of the swivel chute 6 shown in FIG. 1, and the coke is centered from the dedicated coke chute.
  • the central coke layer can be formed in the central region.
  • Example 1 In this example, the blast furnace shown in FIG. 1 was used. Moreover, as a charging raw material used for the present Example, what was shown below was used. Coke ... Bulk density: 0.5 g / cm 3 Ore ... Bulk density: 2.0 g / cm 3
  • a coke layer was formed in the central part, and then an outer peripheral mixed layer was formed in the intermediate part and the peripheral part, which are outer peripheral regions according to the present invention, by reverse tilt charging.
  • the distribution of coke ratio in the outer peripheral mixed layer in the blast furnace radial direction was as follows.
  • Example 1-1 as shown in Table 1, the coke ratio was changed stepwise in the radial direction of the blast furnace.
  • Example 1-2 as shown in Table 1, the coke ratio was set according to the reduction rate distribution obtained from the gas utilization rate distribution.
  • the coke ratio was large in the middle portion and small in the central coke layer adjacent portion and the peripheral portion.
  • the coke ratio was constant in the dimensionless radial direction.
  • the gas utilization rate was determined by the method described above. CO 2 is the CO 2 concentration (volume%), and CO is the CO concentration (volume%). Further, the gas utilization rate distribution was determined by the relationship between CO 2 / (CO 2 + CO) ⁇ 100 and the dimensionless radius.
  • ⁇ is 5% or less.
  • Invention Example 1-2 had ⁇ of 0.3%.
  • ⁇ is indicated by (maximum-minimum) of the ore 1400 ° C. shrinkage rate.
  • ⁇ 4.0%
  • the ventilation resistance in the blast furnace is about 19550 (Pa / m 3 / min).
  • the ventilation resistance in the blast furnace is about 19273 (Pa / m 3 / min).
  • the ventilation resistance in the blast furnace is about 19618 (Pa / m 3 / min).
  • ⁇ 10.5%
  • the ventilation resistance in the blast furnace is about 20038 (Pa / m 3 / min).
  • the ventilation resistance in the blast furnace can be reduced by setting the position to a dimensionless radius of 0.4 or less and the end position of the reverse tilt charging to 0.8 or more.
  • the radial distribution of the coke ratio according to the reduction rate distribution obtained from the gas utilization rate distribution, increasing it in the middle part of the blast furnace, and decreasing it in the central coke layer adjacent part and the peripheral part of the blast furnace. It was proved that the ventilation resistance in the blast furnace can be reduced.
  • Example 2 In order to verify the effect of the present invention, the packed bed pressure loss was examined by simulating a blast furnace lump in the blast furnace using the experimental apparatus shown in FIG.
  • This experimental apparatus is a cylindrical stainless steel cylinder having a diameter of 10 cm as shown in FIG. 5 and can blow a predetermined amount of air (AIR) from the lower part.
  • AIR predetermined amount of air
  • the opening part for measuring the pressure inside a cylinder is provided in the upper end part and lower end part of the said cylinder, and it connects with the pressure gauge with the tube.
  • Inventive Example 2-1 is a raw material in a blast furnace in the case where the mixed coke charging start position is 0.2 in dimensionless radius and the mixed coke charging end position is 0.9 in dimensionless radius due to reverse tilting.
  • the range of the outer peripheral mixed layer was set to a range of a dimensionless radius of 0.2 to 0.9 in the cylinder, and was set in the outer peripheral region according to the present invention.
  • Inventive Examples 2-2 to 2-7 are designed to simulate the state in which the coke ratio is changed stepwise with respect to the radial direction of the blast furnace. I let you. Table 2 also shows the ratio of the amount of coke charged to form the central coke layer with the charge among the coke charged with one charge.
  • Comparative Example 2-1 has a mixed coke charging start position of 0.5
  • Comparative Example 2-2 has a mixed coke charging end position of 0.7. Was outside the outer peripheral region according to the present invention.
  • the air permeability index A (Pa / m 3 / min) is an index obtained by indexing the airflow resistance in the cylinder, and is calculated by the following equation.
  • A (BP-TP) / BGV
  • BP the blowing pressure [Pa].
  • TP the cylinder top pressure [Pa]
  • BGV Bosch gas amount [m 3 (standard state) / min]
  • the reducing index B is the gas utilization rate.
  • the gas utilization rate was determined by the same procedure as in Example 1.
  • the coke ratio in the mixed layer is changed stepwise with respect to the radial direction of the blast furnace, and the reverse tilt charging start position is set to a dimensionless radius of 0.4 or less, and the reverse tilt is performed. It was demonstrated that by setting the charging end position to 0.8 or more, a good reducibility index can be realized while reducing the ventilation resistance in the blast furnace. In addition, if the ratio of the amount of coke charged to form the central coke layer in the charge is 5 to 25% by mass of the coke charged in one charge, the ventilation resistance in the blast furnace is further reduced. It has been demonstrated that it can be done.

Abstract

　The present invention is a method for charging a raw material into a blast furnace in which coke and an ore raw material are charged into the blast furnace using a spiral chute, wherein the method is characterized in having a first step in which the coke is charged into the center region of the blast furnace and a center coke layer is formed, and a second step in which a raw material mixture of the coke and the ore raw material is charged into the outer periphery region located around the outer periphery of the center coke layer and an outer periphery mixture layer is formed, the second step being performed so that the coke ratio in the outer periphery mixture layer varies continuously or incrementally in the radial direction of the blast furnace. It is thereby possible to effectively reduce the ventilation resistance in the blast furnace without the presence of a coke slit.

Description

高炉への原料装入方法Raw material charging method to blast furnace
　本発明は、高炉内への原料装入を、旋回シュートで行う高炉への原料装入方法に関するものである。 The present invention relates to a raw material charging method for a blast furnace in which the raw material is charged into the blast furnace with a turning chute.
　高炉は、一般的に、焼結鉱や、ペレット、塊状鉱石等の鉱石類原料と、コークスとを炉頂より層状に装入したのち、羽口よりガスを流して、銑鉄を得るための設備である。装入された原料であるコークスと鉱石類原料は、炉頂より炉下部へと降下し、鉱石類原料の還元と装入原料の昇温が起こる。そして、鉱石類原料層は、昇温と、上方からの荷重によって、その空隙を埋めながら徐々に変形し、高炉のシャフト部の下方においては、極めて通気抵抗が大きくガスが殆ど流れない融着層となっている。 A blast furnace is generally a facility for obtaining pig iron by flowing a gas from the tuyere after charging ore raw materials such as sintered ore, pellets and massive ore and coke in layers from the top of the furnace. It is. Coke and ore raw material, which are the charged raw materials, descend from the furnace top to the lower part of the furnace, and the reduction of the ore raw materials and the temperature rise of the charged raw materials occur. The ore raw material layer is gradually deformed while filling the voids due to the temperature rise and the load from above, and in the lower part of the shaft part of the blast furnace, the fusion layer has a very high ventilation resistance and hardly flows gas. It has become.
　従来、高炉への原料装入方法は、鉱石類原料とコークスとを交互に装入しており、炉内では鉱石類原料層とコークス層とが交互に層状となっている。また、高炉内下部には、融着帯、すなわち鉱石類原料が軟化融着した通気抵抗の大きな鉱石類原料層と、コークス由来の比較的通気抵抗が小さいコークススリットが存在する。そして、この融着帯の通気性が、高炉全体の通気性に大きく影響を及ぼし、高炉における生産性を律速している。 Conventionally, the raw material charging method into the blast furnace is that the ore raw material and the coke are alternately charged, and the ore raw material layer and the coke layer are alternately layered in the furnace. Further, in the lower part of the blast furnace, there are a cohesive zone, that is, an ore raw material layer having a high airflow resistance in which the ore raw material is softened and fused, and a coke slit having a relatively low airflow resistance derived from coke. The air permeability of the cohesive zone greatly affects the air permeability of the entire blast furnace, thereby limiting the productivity in the blast furnace.
　ここで、融着帯の通気抵抗を改善するためには、鉱石類原料層にコークスを混合することで、コークスが混合された鉱石類原料層由来の融着帯とすることが有効であることが知られている。そして、高炉内の鉱石類原料層の適切な混合状態を得るために、多くの発明が報告されている。
　例えば、特許文献１では、ベルレス高炉において、下流側の鉱石ホッパーにコークスを装入して、コンベア上で鉱石の上にコークスを積層したのち、炉頂バンカーに装入し、鉱石とコークスとを旋回シュートを介して高炉内に装入する方法が開示されている。 Here, in order to improve the ventilation resistance of the cohesive zone, it is effective to make a cohesive zone derived from the ore raw material layer mixed with coke by mixing coke with the ore raw material layer. It has been known. Many inventions have been reported in order to obtain an appropriate mixed state of the ore raw material layer in the blast furnace.
For example, in Patent Document 1, in a bell-less blast furnace, coke is charged into an ore hopper on the downstream side, and coke is stacked on the ore on a conveyor, and then charged into a furnace top bunker. A method for charging into a blast furnace via a turning chute is disclosed.
　また、特許文献２では、異なる炉頂バンカーに鉱石とコークスとを別々に貯留して、コークスと鉱石を同時に混合装入することで、コークスの通常装入用バッチ、コークスの中心装入用バッチ、および混合装入用バッチを形成し、当該バッチを用いた３通りの装入を同時に行う方法が開示されている。 In Patent Document 2, ore and coke are stored separately in different furnace top bunkers, and coke and ore are mixed and charged at the same time, so that a normal coke charging batch and a coke central charging batch are used. , And a method of forming a mixed charging batch and simultaneously performing three types of charging using the batch.
　さらに、特許文献３では、高炉操業における融着帯形状の不安定性および炉内の中心部付近におけるガス利用率の低下を防止し、安全操業と熱効率の向上を図るために、全鉱石と全コークスを完全混合した後、炉内に装入する方法が開示されている。 Further, in Patent Document 3, all ores and all cokes are used to prevent instability of the cohesive zone shape in blast furnace operation and decrease in gas utilization rate near the center of the furnace, and to improve safe operation and thermal efficiency. A method is disclosed in which the components are completely mixed and then charged into the furnace.
特開平３－２１１２１０号公報JP-A-3-211210 特開２００４－１０７７９４号公報JP 2004-107794 A 特公昭５９－１０４０２号公報Japanese Patent Publication No.59-10402
　ここで、近年の高炉操業では、低コークス操業を行う必要性が増えてきている。しかしながら、低コークス操業を行う場合には、使用されるコークス量が減少することから、その対策として、コークススリットを従来以上に薄くする必要がある。そのため、コークススリットの存在比率はますます低下し、融着帯の通気性は、さらに高炉全体の通気性に大きく影響を及ぼすようになる。 Here, in recent blast furnace operations, there is an increasing need for low coke operations. However, when a low coke operation is performed, the amount of coke used is reduced, and as a countermeasure, it is necessary to make the coke slit thinner than before. For this reason, the abundance ratio of coke slits is further reduced, and the air permeability of the cohesive zone further greatly affects the air permeability of the entire blast furnace.
　一方、融着帯の通気抵抗を改善するためには、前述した特許文献３に記載された例のように、鉱石層にコークスを混合することが有効であることが知られている。 On the other hand, in order to improve the ventilation resistance of the cohesive zone, it is known that it is effective to mix coke into the ore layer as in the example described in Patent Document 3 described above.
　しかしながら、前述した特許文献３の記載では、コークススリットがない高炉について記載されてはいるものの、高炉に対する具体的な原料装入方法については言及されていない。 However, in the description of Patent Document 3 described above, although a blast furnace without a coke slit is described, a specific raw material charging method for the blast furnace is not mentioned.
　本発明は、上記従来技術の課題に着目してなされたものである。
　本発明は、混合層でコークススリットを存在させることなく、効果的に混合層の通気抵抗を低減させることができる高炉への原料装入方法を提供することを目的としている。 The present invention has been made paying attention to the above-mentioned problems of the prior art.
An object of this invention is to provide the raw material charging method to the blast furnace which can reduce the ventilation resistance of a mixed layer effectively, without making a coke slit exist in a mixed layer.
　すなわち、本発明の要旨構成は次のとおりである。
１．旋回シュートを使って高炉内にコークスおよび鉱石類原料を装入する高炉への原料装入方法であって、
　前記高炉内の軸心から炉内壁に向かって所定の距離以下の中心領域には、前記コークスを装入して中心コークス層を形成する第１工程と、
　前記中心コークス層の外周に位置する外周領域には、前記コークスと前記鉱石類原料との混合原料を装入して、外周混合層を形成する第２工程と、
を有し、
　前記第２工程は、前記外周混合層中のコークス比が、前記高炉の半径方向に、連続的にまたは段階的に異なるように行い、かつ
　前記第２工程は、前記混合原料を前記外周領域の前記中心領域側から前記炉内壁側に向かって装入する逆傾動装入により行い、
　前記外周領域の内周端を、前記軸心から前記高炉の半径の４０％以下の位置とし、前記外周領域の外周端を、前記軸心から前記高炉の半径の８０％以上の位置とする、高炉への原料装入方法。 That is, the gist configuration of the present invention is as follows.
1. A raw material charging method to a blast furnace in which coke and ore raw materials are charged into the blast furnace using a rotating chute,
A first step of forming a central coke layer by charging the coke in a central region of a predetermined distance or less from an axis in the blast furnace toward the inner wall of the furnace;
A second step of forming an outer peripheral mixed layer by charging a mixed raw material of the coke and the ore raw material into an outer peripheral region located at an outer periphery of the central coke layer;
Have
The second step is performed such that the coke ratio in the outer peripheral mixed layer varies continuously or stepwise in the radial direction of the blast furnace, and the second step uses the mixed raw material in the outer peripheral region. Performed by reverse tilt charging from the central region side toward the furnace inner wall side,
The inner peripheral end of the outer peripheral region is set to a position of 40% or less of the radius of the blast furnace from the axis, and the outer peripheral end of the outer peripheral region is set to a position of 80% or more of the radius of the blast furnace from the axis. Raw material charging method to blast furnace.
２．前記外周領域の内周端を、前記軸心から前記高炉の半径の２５％以下とする、前記１に記載の高炉への原料の装入方法。 2. 2. The raw material charging method to the blast furnace according to 1, wherein an inner peripheral end of the outer peripheral region is set to 25% or less of the radius of the blast furnace from the axis.
３．前記第１工程および前記第２工程を１回ずつ行う１チャージで装入されるコークスの量の５～２５質量％が、該１チャージの前記第１工程で装入される、前記１または２に記載の高炉への原料装入方法。 3. 5 to 25% by mass of the amount of coke charged in one charge in which the first step and the second step are performed once each is charged in the first step of the one charge. The raw material charging method to the blast furnace as described in 1.
４．前記１チャージで装入されるコークスの量の１５～２５質量％が、該１チャージの前記第１工程で装入される、前記１または２に記載の高炉への原料の装入方法。 4). 3. The method for charging a raw material into a blast furnace according to 1 or 2 above, wherein 15 to 25% by mass of the amount of coke charged in one charge is charged in the first step of the one charge.
５．前記高炉の半径方向に関する前記高炉内の一酸化炭素ガスおよび二酸化炭素ガスの濃度の分布を測定し、
　前記濃度分布からガス利用率分布を求め、
　前記ガス利用率分布から、前記高炉の半径方向に関する前記高炉内の還元率分布を求め、
　前記還元率分布に応じて、前記第２工程における、前記コークス比の前記高炉の半径方向の分布を設定する、前記１～４のいずれかに記載の高炉への原料装入方法。 5. Measuring the distribution of the concentration of carbon monoxide gas and carbon dioxide gas in the blast furnace in the radial direction of the blast furnace;
Obtaining the gas utilization rate distribution from the concentration distribution,
From the gas utilization rate distribution, obtain the reduction rate distribution in the blast furnace in the radial direction of the blast furnace,
5. The raw material charging method into the blast furnace according to any one of 1 to 4, wherein a distribution of the coke ratio in the radial direction of the blast furnace in the second step is set according to the reduction rate distribution.
６．前記高炉の内部を、前記軸心から前記炉内壁に向かって前記高炉の半径方向に、中心部と、該中心部の外周に位置する中間部と、該中間部の外周に位置する周辺部とに区画するとき、前記中心コークス層を少なくとも前記中心部に形成し、前記外周混合層を少なくとも前記中間部および前記周辺部に形成し、
　前記中心部または、前記中心部および前記中間部に形成された、前記中心コークス層に対して隣接する領域の前記外周混合層中のコークス比と、前記周辺部での前記外周混合層中のコークス比とを、前記中間部（ただし、前記隣接する領域を除く）での前記外周混合層中のコークス比よりも小さくする、前記１～５のいずれかに記載の高炉への原料装入方法。 6). Inside the blast furnace, in the radial direction of the blast furnace from the axial center toward the inner wall of the furnace, a central part, an intermediate part located on the outer periphery of the central part, and a peripheral part located on the outer periphery of the intermediate part, The central coke layer is formed at least in the central portion, the outer peripheral mixed layer is formed at least in the intermediate portion and the peripheral portion,
The coke ratio in the outer peripheral mixed layer in the central portion or a region adjacent to the central coke layer formed in the central portion and the intermediate portion, and the coke in the outer peripheral mixed layer in the peripheral portion 6. The raw material charging method to the blast furnace according to any one of 1 to 5, wherein the ratio is made smaller than the coke ratio in the outer peripheral mixed layer in the intermediate portion (excluding the adjacent region).
７．前記外周混合層の原料装入開始点を、中心コークス層隣接部とし、各炉頂バンカーから、コークスと、鉱石類原料および/または混合原料とを排出し、集合ホッパーで混合したのち、旋回シュートに供給することによって、前記コークス比を変化させる前記１～６のいずれかに記載の高炉への原料装入方法。 7). The raw material charging start point of the outer peripheral mixed layer is the central coke layer adjacent portion, and the coke and the ore raw material and / or the mixed raw material are discharged from each furnace top bunker, mixed with the collecting hopper, and then the swivel chute 7. The raw material charging method to the blast furnace according to any one of 1 to 6 above, wherein the coke ratio is changed by supplying to the blast furnace.
　本発明によれば、混合層でコークススリットが形成されることがなく、融着帯で、分散しているコークスによって、高炉内の通気改善を行うことができる。 According to the present invention, coke slits are not formed in the mixed layer, and the air flow in the blast furnace can be improved by coke dispersed in the cohesive zone.
本発明に用いる高炉上部の模式図である。It is a schematic diagram of the upper part of a blast furnace used for this invention. 高炉における鉱石類原料とコークスとの混合原料の装入範囲と混合歩留まりとの関係を示した図である。It is the figure which showed the relationship between the charging range of the mixed raw material of the ore raw material and coke in a blast furnace, and a mixing yield. 従来のガス利用率分布の一例を示す図である。It is a figure which shows an example of the conventional gas utilization factor distribution. 従来の高炉内位置における鉱石還元率の一例を示す図である。It is a figure which shows an example of the ore reduction rate in the conventional blast furnace position. 充填層圧力損失評価装置を示す概略構成図である。It is a schematic block diagram which shows a packed bed pressure loss evaluation apparatus.
　以下、本発明の実施形態を具体的に説明する。
　本発明は、旋回シュートを使って、高炉内へ、焼結鉱や、ペレット、塊状鉱石などの高炉操業に当たり一般的に用いられる鉱石類原料と、コークスを、装入する際に用いる高炉への原料装入方法である。 Hereinafter, embodiments of the present invention will be specifically described.
The present invention uses a swirl chute into a blast furnace, ore raw materials generally used for blast furnace operations such as sintered ore, pellets, and massive ore, and coke, when charging coke into the blast furnace. This is a raw material charging method.
　本発明に用いる高炉は、図１に示したようなベルレス式装入装置５を備える。当該装置５は、高炉１の炉頂に配設した複数の炉頂バンカー２ａ～２ｃと、各炉頂バンカーの排出口に配設され、当該炉頂バンカーから排出される原料を混合する集合ホッパー４と、上記集合ホッパーから供給されるコークスや混合原料を受けて高炉内に装入する旋回シュート６を備えている。炉頂バンカー２ａ～２ｃと集合ホッパー４との間には、各炉頂バンカーからの原料の流量を調整する流量調整ゲート３が配設される。
　なお、上記ベルレスタイプの高炉は、旋回シュート６により混合原料等を炉頂より層状に装入し、高炉羽口よりガスを流し、鉄鉱石を還元して銑鉄を得るための一般的な高炉でよい。 The blast furnace used in the present invention includes a bellless charging device 5 as shown in FIG. The apparatus 5 includes a plurality of furnace top bunkers 2a to 2c arranged at the top of the blast furnace 1, and a collecting hopper arranged at the discharge port of each furnace top bunker to mix the raw materials discharged from the furnace top bunker 4 and a swivel chute 6 for receiving coke and mixed raw materials supplied from the collecting hopper and charging them into the blast furnace. Between the furnace top bunkers 2a to 2c and the collecting hopper 4, a flow rate adjusting gate 3 for adjusting the flow rate of the raw material from each furnace top bunker is disposed.
The bell-less type blast furnace is a general blast furnace for charging mixed raw materials or the like from the top of the furnace with a swirl chute 6 and flowing gas from the blast furnace tuyere to reduce iron ore to obtain pig iron. Good.
　本発明では、図１に示したように、前記高炉の内部を、前記軸心から前記炉内壁に向かって、高炉の半径方向に、中心部１３と、該中心部の外周に位置する中間部１４と、該中間部の外周に位置する周辺部１５とに区画する。
　また、高炉内の軸心から炉内壁までの距離をＲとし、Ｒを無次元半径：１と規定する。すなわち、本発明で、高炉内無次元半径（または単に、無次元半径という）とは、高炉内の軸心からの距離をｒ０とすれば、ｒ０／Ｒの式で導き出される数値である。
　本発明で、中心部１３は無次元半径で０以上０．２～０．３以下の領域、中間部は、中心部より外周であって無次元半径で０．２超～０．４以上０．６～０．８以下の領域、周辺部は、無次元半径で０．８超１以下の領域とする。 In the present invention, as shown in FIG. 1, the inside of the blast furnace is centered in the radial direction of the blast furnace from the axial center toward the inner wall of the furnace, and an intermediate part located on the outer periphery of the center part. 14 and a peripheral portion 15 located on the outer periphery of the intermediate portion.
In addition, the distance from the axis in the blast furnace to the inner wall of the furnace is defined as R, and R is defined as a dimensionless radius: 1. That is, in the present invention, the dimensionless radius in the blast furnace (or simply referred to as dimensionless radius) is a numerical value derived by the equation r0 / R, where r0 is the distance from the axis in the blast furnace.
In the present invention, the central portion 13 is a region having a dimensionless radius of 0 to 0.2 to 0.3, and the intermediate portion is an outer periphery from the central portion and has a dimensionless radius of more than 0.2 to 0.4 to 0. The area of 6 to 0.8 or less and the peripheral part is a dimensionless radius of more than 0.8 and 1 or less.
　本発明は、高炉１内の軸心から炉内壁に向かって所定の距離以下の中心領域に、コークスを装入して中心コークス層１１を形成する第１工程と、中心コークス層の外周に位置する外周領域に、コークスと鉱石類原料との混合原料を装入して、外周混合層１２（以下、単に「混合層１２」ともいう。）を形成する第２工程と、を有するものである。 The present invention includes a first step of forming a central coke layer 11 by charging coke in a central region of a predetermined distance or less from an axial center in the blast furnace 1 toward the inner wall of the furnace, and a position on the outer periphery of the central coke layer. And a second step of forming an outer peripheral mixed layer 12 (hereinafter also simply referred to as “mixed layer 12”) by charging a mixed raw material of coke and ore raw material into the outer peripheral region. .
　図１に示した複数の炉頂バンカー２ａ～２ｃは、例えば、炉頂バンカー２ａに、コークスを貯留し、炉頂バンカー２ｂには鉱石類原料を、炉頂バンカー２ｃには鉱石類原料とコークスとを混合させた混合原料を貯留する。そして、混合層１２を形成する際には、各炉頂バンカーから、コークス、鉱石類原料または混合原料を適宜排出し、集合ホッパーで混合して旋回シュートに供給する。 The plurality of furnace top bunkers 2a to 2c shown in FIG. 1 stores, for example, coke in the furnace top bunker 2a, ore raw material in the furnace top bunker 2b, and ore raw material and coke in the furnace top bunker 2c. And the mixed raw material is mixed. When the mixed layer 12 is formed, coke, ore raw material or mixed raw material is appropriately discharged from each furnace top bunker, mixed with a collecting hopper, and supplied to the swivel chute.
　さらに、混合原料を貯留する炉頂バンカーを設けない場合でも、コークスと鉱石類原料とを個別に貯留する炉頂バンカー（例えば、上記炉頂バンカー２ａおよび炉頂バンカー２ｂ）から集合ホッパーに排出することにより、混合層１２を形成することができる。 Further, even when no furnace top bunker for storing the mixed raw material is provided, the coke and the ore raw material are discharged from the furnace top bunker (for example, the furnace top bunker 2a and the furnace top bunker 2b) to the collecting hopper. Thus, the mixed layer 12 can be formed.
　まず、中心コークス層１１を形成する第１工程について説明する。この第１工程は、例えば、コークスの装入開始時に、旋回シュート６が垂直傾動状態に制御され、その後徐々に外周側に向かってコークス層を形成するように制御されることが好ましい。また、中心コークス層を形成してからその周囲に前記外周混合層を形成することが好ましい。中心コークス層内に混合層の鉱石類原料が混入することを防止して、中心コークス層を正確に形成することができるからである。なお、旋回シュート６の先が中心部１３上にあるときに、上記炉頂バンカー２ａからコークスのみを排出して、効率よく中心コークス層１１を形成することができる。 First, the first step for forming the central coke layer 11 will be described. This first step is preferably controlled so that, for example, the turning chute 6 is controlled in a vertically tilted state at the start of charging of the coke, and thereafter a coke layer is gradually formed toward the outer peripheral side. Moreover, it is preferable to form the outer peripheral mixed layer around the central coke layer after the central coke layer is formed. This is because the central coke layer can be accurately formed by preventing the ore raw material of the mixed layer from mixing into the central coke layer. When the tip of the turning chute 6 is on the center portion 13, only the coke can be discharged from the furnace top bunker 2a, and the center coke layer 11 can be formed efficiently.
　本発明で、中心コークス層１１は、高炉内無次元半径で、０（高炉中心）から、０．２～０．３程度までの間に形成するのが好ましい。すなわち、中心コークス層１１の外周は、高炉内無次元半径で、０．２～０．３程度までとなる。また、本発明において、中心コークス層隣接部１６とは、中心コークス層の外周から所定の距離の部分であって、中心コークス層の外周から、高炉内無次元半径：０．３～０．４程度までの部分を言う。 In the present invention, the central coke layer 11 preferably has a dimensionless radius in the blast furnace and is formed between 0 (center of the blast furnace) and about 0.2 to 0.3. That is, the outer periphery of the central coke layer 11 is a dimensionless radius in the blast furnace and is about 0.2 to 0.3. In the present invention, the center coke layer adjacent portion 16 is a portion at a predetermined distance from the outer periphery of the center coke layer, and the dimensionless radius in the blast furnace: 0.3 to 0.4 from the outer periphery of the center coke layer. Say the part to the extent.
　次に、外周混合層１２を形成する第２工程について説明する。外周混合層１２は、中心コークス層１１の外周に形成される。このため、外周混合層１２は、高炉内無次元半径で、０．２以上１以下までの間、すなわち中間部１４および周辺部１５に形成するのが好ましい。 Next, the second step of forming the outer peripheral mixed layer 12 will be described. The outer peripheral mixed layer 12 is formed on the outer periphery of the central coke layer 11. For this reason, it is preferable to form the outer peripheral mixed layer 12 in the blast furnace in a dimensionless radius between 0.2 and 1 or less, that is, in the intermediate portion 14 and the peripheral portion 15.
　本発明に従うと、高炉の中心部１３に中心コークス層１１を形成して、この中心コークス層１１で中心部１３の通気性を確保することができる。また、この中心コークス層１１の外周側に、鉱石類原料とコークスとを混合した混合層１２を形成することができる。それ故、この混合層１２でコークススリットが形成されることはなく、高温ガスが、直接、鉱石類原料間を通過して上昇することができるので、高炉内の通気性と伝熱性とを改善することができる。さらに、本発明では、融着帯の下部にある融着帯中の鉱石類原料と、高温ガスとの接触面積が拡大されて、鉱石類原料の浸炭を効果的に促進することが可能となる。 According to the present invention, the central coke layer 11 is formed in the central portion 13 of the blast furnace, and the air permeability of the central portion 13 can be secured by the central coke layer 11. Moreover, the mixed layer 12 which mixed the ore raw material and coke can be formed in the outer peripheral side of this center coke layer 11. FIG. Therefore, coke slits are not formed in this mixed layer 12, and high-temperature gas can rise directly through the ore raw materials, improving air permeability and heat transfer in the blast furnace. can do. Furthermore, in the present invention, the contact area between the ore raw material in the cohesive zone at the lower part of the cohesive zone and the high-temperature gas is expanded, and carburization of the ore raw material can be effectively promoted. .
　ここで本発明は、外周混合層１２中のコークス比（コークス質量／鉱石類原料質量）（以下、単に、コークス比と言った場合は、外周混合層中のコークスの質量比を意味する）を、高炉の半径方向に対し、連続的にまたは階段状に異なるように、第２工程を行うことを特徴としている。高炉操業に関し、発明者らが鋭意検討した結果、コークス比を、高炉の半径方向に対して、連続的にまたは階段状に異なるようにすると、高炉内の通気改善が効率的にできることを突き止めたからである。 Here, the present invention refers to the coke ratio (coke mass / ore raw material mass) in the outer peripheral mixed layer 12 (hereinafter simply referred to as the coke ratio means the mass ratio of coke in the outer peripheral mixed layer). The second step is performed continuously or stepwise with respect to the radial direction of the blast furnace. As a result of intensive investigations by the inventors regarding blast furnace operation, it has been found that if the coke ratio is varied continuously or stepwise with respect to the radial direction of the blast furnace, the ventilation in the blast furnace can be improved efficiently. It is.
　混合層１２のコークス比が高炉の半径方向に連続的にまたは階段状に異なるように、第２工程を行う手順は、具体的には、コークスの貯留された炉頂バンカー２ａからのコークス切り出し量を変化させることによって集合ホッパー４内での混合原料のコークス比を調整し、この混合原料を旋回シュート６で高炉内の所定の無次元半径の位置に順次供給すれば良い。 The procedure for performing the second step so that the coke ratio of the mixed layer 12 varies continuously or stepwise in the radial direction of the blast furnace is specifically the amount of coke cut out from the furnace top bunker 2a in which coke is stored. The coke ratio of the mixed raw material in the collecting hopper 4 is adjusted by changing the above, and this mixed raw material may be sequentially supplied to the position of a predetermined dimensionless radius in the blast furnace 6 by the turning chute 6.
　本発明において、コークス比が階段状に異なる一例を示せば、無次元半径：０．０５～０．３０の幅でコークス比を一定とし、この一定のコークス比を階段状に異なるように行うことができる。 In the present invention, if an example in which the coke ratio differs stepwise is shown, the coke ratio is made constant with a dimensionless radius: 0.05 to 0.30, and this constant coke ratio is made stepwise different. Can do.
　ここで、上記コークス比の高炉半径方向の分布は、高炉内の通気抵抗が、２０，０００（Ｐａ／ｍ3／ｍｉｎ）程度となるように、鉱石温度が１４００度の時の、鉱石類原料の収縮率（以下、鉱石１４００度収縮率という）の高炉内ばらつきΔρが１０％未満となるように制御すればよい。なお、Δρは、より好ましくは６％以下で、さらに好ましくは２％以下である。また、Δρが６％では、高炉内の通気抵抗が、１９，７００（Ｐａ／ｍ3／ｍｉｎ）程度、Δρが２％では、高炉内の通気抵抗が、１９，４００（Ｐａ／ｍ3／ｍｉｎ）程度である。 Here, the distribution of the coke ratio in the blast furnace radial direction is that the ore raw material when the ore temperature is 1400 degrees so that the ventilation resistance in the blast furnace is about 20,000 (Pa / m 3 / min). The blast furnace variation Δρ of the shrinkage ratio (hereinafter referred to as ore 1400 degree shrinkage ratio) may be controlled to be less than 10%. Δρ is more preferably 6% or less, and further preferably 2% or less. When Δρ is 6%, the ventilation resistance in the blast furnace is about 19,700 (Pa / m 3 / min), and when Δρ is 2%, the ventilation resistance in the blast furnace is 19,400 (Pa / m 3 / min). min).
　本発明において、鉱石１４００度収縮率の高炉内ばらつきΔρとは、荷重軟化試験装置を用い、高炉内を模擬した温度、ガス組成および荷重の条件下で、圧力損失を測定する方法に従って求める。なお、Δρは、中心部１３、中間部１４および周辺部１５において、それぞれ求めた鉱石１４００度収縮率の最高値から最低値を引いたものである。 In the present invention, the in-furnace variation Δρ of the ore 1400 degrees contraction rate is determined according to a method of measuring pressure loss under conditions of temperature, gas composition and load simulating the inside of the blast furnace using a load softening test apparatus. Δρ is obtained by subtracting the lowest value from the highest value of the 1400 degree contraction rate of the ore obtained in the central portion 13, the intermediate portion 14, and the peripheral portion 15, respectively.
　コークス比の高炉半径方向の分布の決定方法としては、ガス利用率分布から求められる還元率分布に応じて決定することも好ましい。通気性の一層の向上効果が得られるからである。
　まず、高炉内の一酸化炭素ガスおよび二酸化炭素ガスの濃度を高炉の半径方向に複数箇所で測定する。各箇所での「ガス利用率」は、ＣＯ2／（ＣＯ2＋ＣＯ）×１００と定義される。なお、この値は、ＣＯ2＋ＣＯガス中のＣＯがどれだけ利用されたかを示す指標である。そして、このガス利用率を縦軸に、高炉半径方向を横軸に取り、それぞれの測定値をプロットすることでガス利用率分布を求めることができる。なお、かかる式に用いるＣＯ2およびＣＯ濃度（体積％）は、水平ゾンデと呼ばれる、高炉内の中心部～周辺部までの稼動式のガス分布を測定する機器を用いて測定する。 As a method of determining the distribution of the coke ratio in the blast furnace radial direction, it is also preferable to determine according to the reduction rate distribution obtained from the gas utilization rate distribution. It is because the further improvement effect of air permeability is acquired.
First, the concentrations of carbon monoxide gas and carbon dioxide gas in the blast furnace are measured at a plurality of locations in the radial direction of the blast furnace. The “gas utilization rate” at each location is defined as CO 2 / (CO 2 + CO) × 100. This value is an index indicating how much CO in the CO 2 + CO gas is used. The gas utilization rate distribution can be obtained by plotting the measured values on the vertical axis and the blast furnace radial direction on the horizontal axis. Note that the CO 2 and CO concentration (volume%) used in such a formula are measured by using a device called a horizontal sonde that measures the operating gas distribution from the center to the periphery in the blast furnace.
　図３は、従来のガス利用率分布の一例を示している。一見、中間部は中心部、周辺部と比較してガス利用率は大きく見える。しかしながら、中間部に存在する鉱石量の多くは、完全には還元が進行していない。そのため、さらにガス利用率を増大させる必要がある。 FIG. 3 shows an example of a conventional gas utilization rate distribution. At first glance, the gas utilization rate seems to be larger in the middle part than in the central part and the peripheral part. However, the reduction of the amount of ore present in the intermediate part has not completely progressed. Therefore, it is necessary to further increase the gas utilization rate.
　また、図４に、従来の高炉内位置における鉱石還元率を原料粒子の温度との関係で示す。図４に示したように、中間部は、周辺部よりも原料粒子の温度を上げないと鉱石還元率が上がらないことから、中間部に存在する鉱石量の多くが、完全には還元が進行していない傾向が確認できる。 FIG. 4 shows the ore reduction rate at the conventional blast furnace position in relation to the temperature of the raw material particles. As shown in FIG. 4, since the ore reduction rate does not increase in the intermediate part unless the temperature of the raw material particles is raised compared to the peripheral part, much of the ore present in the intermediate part is completely reduced. The tendency which is not done can be confirmed.
　第２工程は、混合原料を外周領域の中心領域側から炉内壁側に向かって装入する逆傾動装入により行うことができる。すなわち、旋回シュートの混合原料装入開始点を中心コークス層隣接部１６とし、その後、混合原料中のコークス比を変化させながら、旋回シュート６を炉内壁側に順次移動させて、混合層１２を形成する。 The second step can be performed by reverse tilt charging in which the mixed raw material is charged from the central region side of the outer peripheral region toward the furnace inner wall side. That is, the mixed raw material charging start point of the swirl chute is the central coke layer adjacent portion 16, and then the swirl chute 6 is sequentially moved to the furnace inner wall side while changing the coke ratio in the mixed raw material. Form.
　そして、上記コークス比の高炉半径方向の分布としては、中心コークス層隣接部１６の外周混合層中のコークス比Ａと、周辺部１５での外周混合層中のコークス比Ｂとを、中間部１４（ただし、中心コークス層隣接部１６を除く）での外周混合層中のコークス比Ｃよりも、小さくすることが好ましい。コークスや鉱石類原料の変更毎に原料装入の調整をしなくても、通気性の向上効果が簡便に得られるからである。 As the distribution of the coke ratio in the blast furnace radial direction, the coke ratio A in the outer peripheral mixed layer of the central coke layer adjacent portion 16 and the coke ratio B in the outer peripheral mixed layer at the peripheral portion 15 are divided into the intermediate portion 14. However, it is preferable to make it smaller than the coke ratio C in the outer peripheral mixed layer (excluding the central coke layer adjacent portion 16). This is because the effect of improving the air permeability can be easily obtained without adjusting the raw material charging every time the coke or ore raw material is changed.
　ここで、コークス比Ｃは１６０～３００ｋｇ／ｔの範囲内とすることが好ましい。また、コークス比Ａ，Ｂは、コークス比Ｃよりも、７／１０程度に小さくすることが好ましい。より好ましくは、１／２程度である。 Here, the coke ratio C is preferably in the range of 160 to 300 kg / t. Further, the coke ratios A and B are preferably smaller than the coke ratio C by about 7/10. More preferably, it is about 1/2.
　また、コークス比Ａとコークス比Ｂとは、同じであっても、どちらか一方が大きくても良いが、Ａに対するＢの量が１．２倍程度差を設けるのも好ましい。 Further, the coke ratio A and the coke ratio B may be the same or either one may be large, but it is also preferable that the amount of B with respect to A is different by about 1.2 times.
　また、本発明では、外周領域の内周端を無次元半径で０．４以下（高炉の半径の４０％以下の位置）とし、外周領域の外周端を無次元半径で０．８以上（高炉の半径の８０％以上の位置）として混合層の装入範囲を広くすることが重要である。
　逆傾動装入の開始位置を外周領域の内周端より炉中心側とすると、混合層中のコークスの偏析による高炉内部の通気性の悪化を防止することができるからである。
　なお、逆傾動装入の開始位置は、無次元半径で０．２５以下とするのがより好ましい。より炉中心側から装入することで、より安定的な堆積形状の形成することと、混合層中のコークスの偏析を防止することができるからである。
　また、逆傾動装入の開始位置は、中心コークス層が効果的に機能するために、無次元半径で０．２程度が好ましい。 Further, in the present invention, the inner peripheral end of the outer peripheral region is a dimensionless radius of 0.4 or less (a position of 40% or less of the blast furnace radius), and the outer peripheral end of the outer peripheral region is a dimensionless radius of 0.8 or more (blast furnace) It is important to widen the charging range of the mixed layer as a position of 80% or more of the radius of the above.
This is because, if the reverse tilt charging start position is set to the furnace center side from the inner peripheral end of the outer peripheral region, deterioration of the air permeability inside the blast furnace due to segregation of coke in the mixed layer can be prevented.
The starting position of reverse tilt charging is more preferably 0.25 or less in dimensionless radius. This is because the more stable deposition shape can be formed and the segregation of coke in the mixed layer can be prevented by charging from the furnace center side.
The starting position of reverse tilt charging is preferably about 0.2 in dimensionless radius so that the central coke layer functions effectively.
　一方、逆傾動装入の終了位置を外周領域の外周端より炉壁側としたのは、軸心側へ流れやすい混合層中のコークスを、炉壁側へ堆積させることができ、混合層中のコークスの偏析による高炉内部の通気性の悪化を防止することができるからである。また、逆傾動装入の終了位置は無次元半径で１であっても良いが、設備効率の点からは、０．９５程度が好ましい。
　逆傾動装入の終了位置から炉内壁までは、コークス層のみでも良いが、通気性の確保が可能であれば原料の粒度に応じてコークス層と鉱石層と混合層の層厚を適宜調整したものでも良い。 On the other hand, the end position of the reverse tilt charging is set to the furnace wall side from the outer peripheral edge of the outer peripheral region because coke in the mixed layer that easily flows to the axial center side can be deposited on the furnace wall side. This is because deterioration of the air permeability inside the blast furnace due to segregation of coke can be prevented. The end position of reverse tilt charging may be a dimensionless radius of 1, but is preferably about 0.95 from the viewpoint of equipment efficiency.
From the end of reverse tilt charging to the inner wall of the furnace, only the coke layer may be used, but the thickness of the coke layer, the ore layer, and the mixed layer was appropriately adjusted according to the particle size of the raw material if it is possible to ensure air permeability. Things can be used.
　この逆傾動装入によると、高炉の中心領域に中心コークス層を形成して、この中心コークス層で中心領域の通気性を確保することができる。それ故、本発明では、この外周混合層でコークススリットが形成されなくても、高温ガスが直接鉱石類原料間を通過して上昇することにより、通気性と伝熱性とを改善することができる。 According to this reverse tilt charging, a central coke layer can be formed in the central area of the blast furnace, and the central coke layer can ensure air permeability in the central area. Therefore, in the present invention, even if the coke slit is not formed in the outer peripheral mixed layer, the high temperature gas can directly pass between the ore raw materials and rise, thereby improving air permeability and heat transfer. .
　前掲した図２を用いて、上記のように逆傾動装入による混合原料の装入範囲を広くするにより通気性および伝熱性を改善できることを説明する。図２は、以下の実機試験を行った結果である。炉内の中心領域にコークス層を形成し、その後、逆傾動装入により外周領域に混合層を形成した。混合現状の装入範囲を種々変更して、それぞれ場合の混合歩留まりを求めた。 Referring to FIG. 2 described above, it will be described that the air permeability and heat transfer can be improved by widening the charging range of the mixed raw material by reverse tilt charging as described above. FIG. 2 shows the results of the following actual machine test. A coke layer was formed in the central region in the furnace, and then a mixed layer was formed in the outer peripheral region by reverse tilt charging. Various charging ranges were mixed and the mixing yield in each case was determined.
　図２において、Δｒは、混合原料を装入する範囲、すなわち外周混合層の形成範囲を示している。ここで、混合原料の装入開始位置、混合原料の装入終了位置の高炉軸心からの距離を各々ｒ１、ｒ２とすると、Δｒはｒ２－ｒ１を意味するから、横軸は（ｒ２－ｒ１）／Ｒを示している。そして、図２からΔｒが大きいほど混合歩留まりが良好であることが分かる。すなわち、混合原料の装入が、ｒ２が大きくなる炉の周辺部に行くほど、コークスと鉱石類原料との偏析が少なくなることを表している。
　なお、混合歩留まりは、半径方向においてコークスの偏析状況を示しており、数値が大きい程コークスが均一に混合されたことを示している（１００であれば全く偏析がないことを意味する。）。 In FIG. 2, Δr indicates a range in which the mixed raw material is charged, that is, a formation range of the outer peripheral mixed layer. Here, when the distance from the blast furnace axis center of the mixed raw material charging start position and the mixed raw material charging end position is r1 and r2, respectively, Δr means r2-r1, and the horizontal axis is (r2-r1 ) / R. It can be seen from FIG. 2 that the mixing yield is better as Δr is larger. That is, it shows that the segregation of coke and an ore raw material decreases, so that charging of a mixed raw material goes to the peripheral part of the furnace where r2 becomes large.
The mixed yield indicates the segregation state of coke in the radial direction, and the larger the value, the more uniformly the coke is mixed (100 means no segregation at all).
　ここで、上記混合歩留まりは、以下の式により求めることができる。
　混合歩留まり（％）　＝（平均投入量　－　σ混合量）／平均投入量×１００
　平均投入量は、装入シュートで装入する際の投入量（質量％）、σ混合量は、投入箇所の各点におけるコークスの混合量から求められるΔｒ内の標準偏差を表す。 Here, the mixed yield can be obtained by the following equation.
Mixing yield (%) = (Average input amount-σ mixing amount) / Average input amount x 100
The average charging amount represents the charging amount (% by mass) when charging with the charging chute, and the σ mixing amount represents a standard deviation within Δr obtained from the mixing amount of coke at each point of the charging point.
　本発明では、中心コークス層の形成のために装入されるコークス量を、１チャージ当たりのコークス装入量の５～２５質量％の範囲とすることが好ましい。これにより、混合層中のコークスの中心領域への流入（中心流という）の抑制を回避することができるからである。
　また、上記１チャージ当たりのコークス装入量の下限比率は、１５質量％がより好ましい。上記中心流を維持できかつ、安定した混合層を形成できるからである。
　なお、本発明における１チャージとは、前記第１工程および前記第２工程を１回ずつ行う行為のことを意味する。 In the present invention, the amount of coke charged for forming the central coke layer is preferably in the range of 5 to 25% by mass of the amount of coke charged per charge. This is because it is possible to prevent the coke in the mixed layer from flowing into the central region (referred to as the central flow).
The lower limit ratio of the amount of coke charged per charge is more preferably 15% by mass. This is because the central flow can be maintained and a stable mixed layer can be formed.
In addition, 1 charge in this invention means the action which performs the said 1st process and the said 2nd process once.
　さらに、本発明では、高炉の中心領域にコークスを投入するコークス専用シュート（図示せず）を、前掲した図１の旋回シュート６の旋回領域外に設け、該コークス専用シュートからコークスを中心部に装入することにより、中心コークス層を中心領域に形成するようにすることもできる。
　この手法を用いると、コークス専用シュートによってコークスを高炉の中心部に投入することで、中心コークス層を正確に形成することができるという利点がある。 Furthermore, in the present invention, a coke dedicated chute (not shown) for charging coke into the central region of the blast furnace is provided outside the swivel region of the swivel chute 6 shown in FIG. 1, and the coke is centered from the dedicated coke chute. By charging, the central coke layer can be formed in the central region.
When this method is used, there is an advantage that the central coke layer can be accurately formed by throwing the coke into the center of the blast furnace using a dedicated coke chute.
［実施例１］
　本実施例は、前掲図１に示した高炉を用いて実施した。また、本実施例に用いた装入原料としては、以下に示すものを用いた。
　コークス・・・嵩密度：０．５ｇ／ｃｍ3
　鉱石　　・・・嵩密度：２．０ｇ／ｃｍ3 [Example 1]
In this example, the blast furnace shown in FIG. 1 was used. Moreover, as a charging raw material used for the present Example, what was shown below was used.
Coke ... Bulk density: 0.5 g / cm 3
Ore ... Bulk density: 2.0 g / cm 3
　中心部にコークス層を形成し、その後、逆傾動装入により、本発明に従う外周領域である、中間部および周辺部に外周混合層を形成した。このとき、外周混合層中のコークス比の高炉半径方向分布を以下のとおりとした。 A coke layer was formed in the central part, and then an outer peripheral mixed layer was formed in the intermediate part and the peripheral part, which are outer peripheral regions according to the present invention, by reverse tilt charging. At this time, the distribution of coke ratio in the outer peripheral mixed layer in the blast furnace radial direction was as follows.
　発明例１－１では、表１に示しめすように、コークス比を、高炉の半径方向に対し、階段状に変化させたものとした。
　発明例１－２では、表１に示したように、コークス比を、ガス利用率分布から求められる還元率分布に応じて設定した。
　発明例１－３は、表１に示したように、コークス比を、中間部では大きく、中心コークス層隣接部および周辺部では小さくした。
　比較例１－１は、コークス比を無次元半径方向に一定とした。 In Invention Example 1-1, as shown in Table 1, the coke ratio was changed stepwise in the radial direction of the blast furnace.
In Invention Example 1-2, as shown in Table 1, the coke ratio was set according to the reduction rate distribution obtained from the gas utilization rate distribution.
In Invention Example 1-3, as shown in Table 1, the coke ratio was large in the middle portion and small in the central coke layer adjacent portion and the peripheral portion.
In Comparative Example 1-1, the coke ratio was constant in the dimensionless radial direction.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　なお、発明例１－２では、ガス利用率は、既述の方法で求めた。また、ＣＯ2はＣＯ2濃度（体積％）、ＣＯはＣＯ濃度（体積％）である。
　さらに、ガス利用率分布を、ＣＯ2／（ＣＯ2＋ＣＯ）×１００の値を無次元半径との関係で求めた。 In Invention Example 1-2, the gas utilization rate was determined by the method described above. CO 2 is the CO 2 concentration (volume%), and CO is the CO concentration (volume%).
Further, the gas utilization rate distribution was determined by the relationship between CO 2 / (CO 2 + CO) × 100 and the dimensionless radius.
〔鉱石１４００度収縮率〕
　上記発明例１－１～１－３および比較例の鉱石１４００度収縮率：Ｓｒを以下の式より求めた。
　Ｓｒ　＝　（１．８０×Ｒ　―２．５９）×Ｍ　―　２３．３×Ｒ　＋　８５．７
　　Ｒ：モデル推定される１２００　℃還元率　［％］
　　Ｍ：コークス混合量　　［質量％］
　上記試験の結果を表１に併記する。なお、表中、Ｓｒ値については表１に示した比較例の中間の値を１００に換算して比較した。 [Ore 1400 degree shrinkage]
The ore of the above invention examples 1-1 to 1-3 and the comparative example 1400 degree shrinkage ratio: Sr was obtained from the following formula.
Sr = (1.80 × R−2.59) × M−23.3 × R + 85.7
R: Model estimated 1200 ° C. reduction rate [%]
M: Coke mixing amount [mass%]
The results of the above test are also shown in Table 1. In addition, about the Sr value in the table | surface, the intermediate value of the comparative example shown in Table 1 was converted into 100, and compared.
　発明の条件を満足する発明例１－１～１－３は、何れも、Δρが、５％以下となっている。特に、発明例１－２は、Δρが、０．３％であった。なお、Δρは、鉱石１４００℃収縮率の（最大―最小）で示した。
　また、Δρが４．０％では、高炉内の通気抵抗は、１９５５０（Ｐａ／ｍ3／ｍｉｎ）程度である。Δρが０．３％では、高炉内の通気抵抗は、１９２７３（Ｐａ／ｍ3／ｍｉｎ）程度である。Δρが４．９％では、高炉内の通気抵抗は、１９６１８（Ｐａ／ｍ3／ｍｉｎ）程度である。Δρが１０．５％では、高炉内の通気抵抗は、２００３８（Ｐａ／ｍ3／ｍｉｎ）程度である。 In each of Invention Examples 1-1 to 1-3 satisfying the conditions of the invention, Δρ is 5% or less. In particular, Invention Example 1-2 had Δρ of 0.3%. Δρ is indicated by (maximum-minimum) of the ore 1400 ° C. shrinkage rate.
When Δρ is 4.0%, the ventilation resistance in the blast furnace is about 19550 (Pa / m 3 / min). When Δρ is 0.3%, the ventilation resistance in the blast furnace is about 19273 (Pa / m 3 / min). When Δρ is 4.9%, the ventilation resistance in the blast furnace is about 19618 (Pa / m 3 / min). When Δρ is 10.5%, the ventilation resistance in the blast furnace is about 20038 (Pa / m 3 / min).
　以上の結果から、中心コークス層の外側に、鉱石類原料とコークスとの混合層を装入する際に、混合層中のコークス比を高炉の半径方向に変化させ、さらに逆傾動装入の開始位置を無次元半径で０．４以下とし、かつ該逆傾動装入の終了位置を０．８以上とすることで、高炉内の通気抵抗を低滅できることが実証された。特に、コークス比の半径方向分布を、ガス利用率分布から求められる還元率分布に応じて設定したり、高炉中間部では増加させ、中心コークス層隣接部および高炉周辺部では低下させたりすることで、高炉内の通気抵抗を低滅できることが実証された。 From the above results, when charging the mixed layer of ore raw material and coke outside the central coke layer, the coke ratio in the mixed layer was changed in the radial direction of the blast furnace, and the reverse tilt charging was started. It was demonstrated that the ventilation resistance in the blast furnace can be reduced by setting the position to a dimensionless radius of 0.4 or less and the end position of the reverse tilt charging to 0.8 or more. In particular, by setting the radial distribution of the coke ratio according to the reduction rate distribution obtained from the gas utilization rate distribution, increasing it in the middle part of the blast furnace, and decreasing it in the central coke layer adjacent part and the peripheral part of the blast furnace. It was proved that the ventilation resistance in the blast furnace can be reduced.
［実施例２］
　本発明の効果を実証するために、図５に示す実験装置を用いて、高炉内の高炉塊状帯を模擬して、その充填層圧力損失を調べた。
　この実験装置は、図５に示したように直径：１０ｃｍの円筒形のステンレス鋼製の筒であって、下部から所定量の空気（ＡＩＲ）を吹きこむことができる。そして、上記筒の上端部および下端部には、筒内部の圧力を測定するための開孔部が設けられ、圧力計にチューブでつながっている。 [Example 2]
In order to verify the effect of the present invention, the packed bed pressure loss was examined by simulating a blast furnace lump in the blast furnace using the experimental apparatus shown in FIG.
This experimental apparatus is a cylindrical stainless steel cylinder having a diameter of 10 cm as shown in FIG. 5 and can blow a predetermined amount of air (AIR) from the lower part. And the opening part for measuring the pressure inside a cylinder is provided in the upper end part and lower end part of the said cylinder, and it connects with the pressure gauge with the tube.
　ここで、以下の実施例に用いた装入原料としては、以下に示すものを用いた。
　コークス・・・嵩密度：０．５ｇ／ｃｍ3
　鉱石　　・・・嵩密度：２．０ｇ／ｃｍ3 Here, the following materials were used as the charging materials used in the following examples.
Coke ... Bulk density: 0.5 g / cm 3
Ore ... Bulk density: 2.0 g / cm 3
　発明例２－１は、逆傾動で混合コークス装入の開始位置を無次元半径で０．２とし、混合コークス装入の終了位置を無次元半径で０．９とした場合の高炉内の原料装入状態を模擬するべく、外周混合層の範囲を筒内の無次元半径０．２～０．９の範囲として、本発明に従う外周領域内とした。 Inventive Example 2-1 is a raw material in a blast furnace in the case where the mixed coke charging start position is 0.2 in dimensionless radius and the mixed coke charging end position is 0.9 in dimensionless radius due to reverse tilting. In order to simulate the charging state, the range of the outer peripheral mixed layer was set to a range of a dimensionless radius of 0.2 to 0.9 in the cylinder, and was set in the outer peripheral region according to the present invention.
　発明例２－２～２－７は、高炉の半径方向に対してコークス比を階段状に変化させた状態を模擬するために、表２に示したコークス比を本発明に従う外周領域内で変化させた。また、１チャージで装入されるコークスのうち該チャージで中心コークス層の形成のために装入されるコークス量の比率を、表２に併記している。
　他方、比較例２－１は、混合コークス装入の開始位置を、０．５とし、比較例２－２は、混合コークス装入の終了位置を、０．７として、混合コークス装入の位置を、本発明に従う外周領域外とした。 Inventive Examples 2-2 to 2-7 are designed to simulate the state in which the coke ratio is changed stepwise with respect to the radial direction of the blast furnace. I let you. Table 2 also shows the ratio of the amount of coke charged to form the central coke layer with the charge among the coke charged with one charge.
On the other hand, Comparative Example 2-1 has a mixed coke charging start position of 0.5, and Comparative Example 2-2 has a mixed coke charging end position of 0.7. Was outside the outer peripheral region according to the present invention.
　表２中、通気性指標Ａ（Ｐａ／ｍ3／ｍｉｎ）は、筒内での通気抵抗を指数化した指標であり、次式により算出する。
　　Ａ＝（ＢＰ－ＴＰ）／ＢＧＶ
　　ここで、ＢＰは送風圧力［Ｐａ］
　　　　　　ＴＰは筒頂圧力［Ｐａ］
　　　　　　ＢＧＶはボッシュガス量［ｍ3（標準状態）／ｍｉｎ］ In Table 2, the air permeability index A (Pa / m 3 / min) is an index obtained by indexing the airflow resistance in the cylinder, and is calculated by the following equation.
A = (BP-TP) / BGV
Here, BP is the blowing pressure [Pa].
TP is the cylinder top pressure [Pa]
BGV is Bosch gas amount [m 3 (standard state) / min]
　また、表２中、還元性指標Ｂは、ガス利用率である。ガス利用率は、実施例１と同様の手順で求めた。 In Table 2, the reducing index B is the gas utilization rate. The gas utilization rate was determined by the same procedure as in Example 1.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２の結果から、混合層中のコークス比を、高炉の半径方向に対して階段状に変化させ、さらに逆傾動装入の開始位置を無次元半径で０．４以下とし、かつ該逆傾動装入の終了位置を０．８以上とすることで、高炉内の通気抵抗を低滅しつつ、良好な還元性指標を実現できることが実証された。また、１チャージで装入されるコークスのうち該チャージで中心コークス層の形成のために装入されるコークス量の比率を５～２５質量％とすれば、高炉内の通気抵抗を一層低滅できることが実証された。 From the results shown in Table 2, the coke ratio in the mixed layer is changed stepwise with respect to the radial direction of the blast furnace, and the reverse tilt charging start position is set to a dimensionless radius of 0.4 or less, and the reverse tilt is performed. It was demonstrated that by setting the charging end position to 0.8 or more, a good reducibility index can be realized while reducing the ventilation resistance in the blast furnace. In addition, if the ratio of the amount of coke charged to form the central coke layer in the charge is 5 to 25% by mass of the coke charged in one charge, the ventilation resistance in the blast furnace is further reduced. It has been demonstrated that it can be done.
　１　高炉
　２ａ～２ｃ　炉頂バンカー
　３　流量調整ゲート
　４　集合ホッパー
　５　ベルレス式装入装置
　６　旋回シュート
　１１　中心コークス層
　１２　外周混合層
　１３　中心部
　１４　中間部
　１５　周辺部
　１６　中心コークス層隣接部 DESCRIPTION OF SYMBOLS 1 Blast furnace 2a-2c Top bunker 3 Flow control gate 4 Collective hopper 5 Bellless type charging device 6 Turning chute 11 Central coke layer 12 Outer peripheral mixing layer 13 Central part 14 Intermediate part 15 Peripheral part 16 Central coke layer adjacent part

Claims (7)

  1. 　旋回シュートを使って高炉内にコークスおよび鉱石類原料を装入する高炉への原料装入方法であって、
    　前記高炉内の軸心から炉内壁に向かって所定の距離以下の中心領域には、前記コークスを装入して中心コークス層を形成する第１工程と、
    　前記中心コークス層の外周に位置する外周領域には、前記コークスと前記鉱石類原料との混合原料を装入して、外周混合層を形成する第２工程と、
    を有し、
    　前記第２工程は、前記外周混合層中のコークス比が、前記高炉の半径方向に、連続的にまたは段階的に異なるように行い、かつ
    　前記第２工程は、前記混合原料を前記外周領域の前記中心領域側から前記炉内壁側に向かって装入する逆傾動装入により行い、
    　前記外周領域の内周端を、前記軸心から前記高炉の半径の４０％以下の位置とし、前記外周領域の外周端を、前記軸心から前記高炉の半径の８０％以上の位置とする、高炉への原料装入方法。     A raw material charging method to a blast furnace in which coke and ore raw materials are charged into the blast furnace using a rotating chute,
    A first step of forming a central coke layer by charging the coke in a central region of a predetermined distance or less from an axis in the blast furnace toward the inner wall of the furnace;
    A second step of forming an outer peripheral mixed layer by charging a mixed raw material of the coke and the ore raw material into an outer peripheral region located at an outer periphery of the central coke layer;
    Have
    The second step is performed such that the coke ratio in the outer peripheral mixed layer varies continuously or stepwise in the radial direction of the blast furnace, and the second step uses the mixed raw material in the outer peripheral region. Performed by reverse tilt charging from the central region side toward the furnace inner wall side,
    The inner peripheral end of the outer peripheral region is set to a position of 40% or less of the radius of the blast furnace from the axis, and the outer peripheral end of the outer peripheral region is set to a position of 80% or more of the radius of the blast furnace from the axis. Raw material charging method to blast furnace.
  2. 　前記外周領域の内周端を、前記軸心から前記高炉の半径の２５％以下とする、請求項１に記載の高炉への原料装入方法。 The raw material charging method to the blast furnace according to claim 1, wherein an inner peripheral end of the outer peripheral region is set to 25% or less of a radius of the blast furnace from the axis.
  3. 　前記第１工程および前記第２工程を１回ずつ行う１チャージで装入されるコークスの量の５～２５質量％が、該１チャージの前記第１工程で装入される、請求項１または２に記載の高炉への原料装入方法。 The amount of coke charged in one charge in which each of the first step and the second step is performed once is charged in an amount of 5 to 25% by mass in the first step of the one charge. The raw material charging method to the blast furnace as described in 2.
  4. 　前記１チャージで装入されるコークスの量の１５～２５質量％が、該１チャージの前記第１工程で装入される、請求項１または２に記載の高炉への原料装入方法。 The method for charging raw material into a blast furnace according to claim 1 or 2, wherein 15 to 25 mass% of the amount of coke charged in one charge is charged in the first step of the one charge.
  5. 　前記高炉の半径方向に関する前記高炉内の一酸化炭素ガスおよび二酸化炭素ガスの濃度分布を測定し、
    　前記濃度分布からガス利用率分布を求め、
    　前記ガス利用率分布から、前記高炉の半径方向に関する前記高炉内の還元率分布を求め、
    　前記還元率分布に応じて、前記第２工程における、前記コークス比の前記高炉の半径方向の分布を設定する、請求項１～４のいずれか一項に記載の高炉への原料装入方法。     Measure the concentration distribution of carbon monoxide gas and carbon dioxide gas in the blast furnace in the radial direction of the blast furnace,
    Obtaining the gas utilization rate distribution from the concentration distribution,
    From the gas utilization rate distribution, obtain the reduction rate distribution in the blast furnace in the radial direction of the blast furnace,
    The method of charging a raw material into a blast furnace according to any one of claims 1 to 4, wherein a distribution of the coke ratio in the radial direction of the blast furnace in the second step is set according to the reduction rate distribution.
  6. 　前記高炉の内部を、前記軸心から前記炉内壁に向かって前記高炉の半径方向に、中心部と、該中心部の外周に位置する中間部と、該中間部の外周に位置する周辺部とに区画するとき、前記中心コークス層を少なくとも前記中心部に形成し、前記外周混合層を少なくとも前記中間部および前記周辺部に形成し、
    　前記中心部または、前記中心部および前記中間部に形成された、前記中心コークス層に対して隣接する領域の前記外周混合層中のコークス比と、前記周辺部での前記外周混合層中のコークス比とを、前記中間部（ただし、前記隣接する領域を除く）での前記外周混合層中のコークス比よりも小さくする、請求項１～５のいずれか一項に記載の高炉への原料装入方法。     Inside the blast furnace, in the radial direction of the blast furnace from the axial center toward the inner wall of the furnace, a central part, an intermediate part located on the outer periphery of the central part, and a peripheral part located on the outer periphery of the intermediate part, The central coke layer is formed at least in the central portion, the outer peripheral mixed layer is formed at least in the intermediate portion and the peripheral portion,
    The coke ratio in the outer peripheral mixed layer in the central portion or a region adjacent to the central coke layer formed in the central portion and the intermediate portion, and the coke in the outer peripheral mixed layer in the peripheral portion The raw material charge to the blast furnace according to any one of claims 1 to 5, wherein the ratio is smaller than the coke ratio in the outer peripheral mixed layer in the intermediate portion (excluding the adjacent region). How to enter.
  7. 　前記外周混合層の原料装入開始点を、中心コークス層隣接部とし、各炉頂バンカーから、コークスと、鉱石類原料および/または混合原料とを排出し、集合ホッパーで混合したのち、旋回シュートに供給することによって、前記コークス比を変化させる請求項１～６のいずれか一項に記載の高炉への原料装入方法。 The raw material charging start point of the outer peripheral mixed layer is the central coke layer adjacent portion, and the coke and the ore raw material and / or the mixed raw material are discharged from each furnace top bunker, mixed with the collecting hopper, and then the swivel chute The method for charging a raw material into a blast furnace according to any one of claims 1 to 6, wherein the coke ratio is changed by supplying to the blast furnace.
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WO2013172045A1 (en) * 2012-05-18 2013-11-21 Ｊｆｅスチール株式会社 Method for charging starting material into blast furnace
JP2013241641A (en) * 2012-05-18 2013-12-05 Jfe Steel Corp Method for charging raw material into blast furnace

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013172045A1 (en) * 2012-05-18 2013-11-21 Ｊｆｅスチール株式会社 Method for charging starting material into blast furnace
JP2013241641A (en) * 2012-05-18 2013-12-05 Jfe Steel Corp Method for charging raw material into blast furnace

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