Operation method for blast furnace and blast furnace supplementary facility

Abstract

To provide an operation method for a blast furnace and a blast furnace supplementary facility that suppress the decrease in the heat generation of B gas while maintaining the CO2 emission reduction effect achieved by charging solid carbon materials etc. in the blast furnace operation where solid carbon materials are charged into the blast furnace from the top of a blast furnace.SOLUTION: An operation method for a blast furnace according to the present invention comprises a charging process of charging solid carbon material manufactured by dry distillation of woody biomass into the blast furnace in the operation of the blast furnace in which solid carbon material is charged into the blast furnace from the blast furnace top, and a blowing process of blowing carbonization gas into the blast furnace. Furthermore, the blast furnace supplementary facility according to the present invention comprises a charcoal furnace for generating solid carbon and carbonization gas from woody biomass, a solid carbon introduction path for introducing the solid carbon generated from the charcoal furnace into the blast furnace from the top of the blast furnace, and a pyrolysis gas introduction path for introducing the carbonization gas into the blast furnace.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for operating a blast furnace and auxiliary equipment for a blast furnace that can reduce the amount of carbon input during blast furnace operation.

Background Art

[0002] Generally, in blast furnace operation, iron-based raw materials and coke are charged in layers from the top of the furnace, and hot air (high-temperature air) and a reducing aid such as pulverized coal are blown in from tuyeres at the lower part of the furnace. By reducing the iron-based raw materials descending in the furnace with the reducing gas ascending from the lower part of the furnace, pig iron is produced.

[0003] As described above, in blast furnace operation, carbon-based reducing materials such as coke and pulverized coal are used to reduce the iron source in the furnace. Since the carbon input into the blast furnace is discharged as carbon dioxide (CO2) from the top of the furnace, contributing to the promotion of global warming, reducing the amount of carbon input is an important issue in blast furnace operation.

[0004] As a method for reducing the CO2 emissions from a blast furnace, the use of biomass carbon materials as an alternative to carbon materials derived from fossil fuels such as coke and pulverized coal is promising. Due to the carbon-neutral nature of biomass carbon materials, even when burned, they are not counted as CO2 generation, and the substantial amount of carbon input can be regarded as zero.

[0005] As a typical biomass carbon material, for example, charcoal can be mentioned. As disclosed in Patent Document 1, there is a technique of mixing and charging charcoal into an ore layer from the top of a blast furnace as an alternative to coke. However, in such an operation, only the charged charcoal content can substantially reduce the amount of carbon input. Hereinafter, the "amount of carbon input" shall refer only to the substantial amount of carbon excluding carbon-neutral carbon. Also, the "CO2 emissions" shall refer to the amount of CO2 emissions generated from the substantial carbon input excluding carbon-neutral carbon.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In the technology disclosed in Cited Document 1, by charging charcoal into a blast furnace, the reducing agent (coke or pulverized coal) is replaced with carbon-neutral charcoal, and the high reactivity of the charcoal also improves the reduction efficiency of iron ore, so the CO2 emissions can be significantly reduced. However, when operating by charging charcoal or the like from the top of the blast furnace to reduce CO2 emissions, the amount of reducing gas (mainly carbon monoxide) generated in the furnace decreases due to a significant reduction in the amount of reducing agent used. Therefore, there is a problem that the calorific value of the blast furnace gas (B gas) discharged from the top of the furnace decreases.

[0008] B gas is used in each process of steelmaking (sintering, coke oven, hot blast stove, power plant), and the surplus is also used as M gas in the processes after steelmaking (steelmaking, rolling, etc.) and is an important energy source in the steelworks. Therefore, if the calorific value of B gas decreases, there is a risk of causing combustion instability troubles in the in-plant combustion equipment.

[0009] The present invention has been made in view of the above problems, and an object thereof is to provide a method for operating a blast furnace and blast furnace auxiliary equipment that suppresses a decrease in the calorific value of B gas while maintaining the CO2 emission reduction effect due to charging of woody biomass or the like in the operation of charging solid carbonaceous materials from the top of the blast furnace.

Means for Solving the Problems

[0010] The method for operating a blast furnace according to the present invention includes a charging step of charging a solid carbonaceous material produced by carbonizing a woody biomass into a blast furnace in the operation of charging a solid carbonaceous material from the top of the blast furnace, and a blowing step of blowing the carbonization gas into the blast furnace.

[0011] In the operation method of the blast furnace according to the present invention configured as described above, (1) In the blowing step, after separating and removing CO2 from the dry distillation gas, blowing the dry distillation gas from which CO2 has been separated and removed into the blast furnace; (2) In the blowing step, setting the blowing amount of the dry distillation gas according to the amount of solid carbon material charged into the blast furnace; (3) The blowing amount of the dry distillation gas satisfies the following formula (1); Dry distillation gas ratio [kg / t] ≥ Solid carbon material ratio [kg / t] × 0.35 ··· (1) (4) The blowing amount of the dry distillation gas satisfies the following formula (2); Dry distillation gas ratio [kg / t] ≥ Solid carbon material ratio [kg / t] × 0.40 ··· (2) are considered to be more preferable solutions.

[0012] In addition, the auxiliary equipment of the blast furnace of the present invention includes a charcoal furnace that generates solid carbon material and dry distillation gas from woody biomass, a solid carbon material introduction path that introduces the solid carbon material generated from the charcoal furnace to the top of the blast furnace, and a dry distillation gas introduction path that introduces the dry distillation gas into the blast furnace.

[0013] In the auxiliary equipment of the blast furnace according to the present invention configured as described above, it is considered to be a more preferable solution to provide a CO2 separation device in the dry distillation gas introduction path.

Effects of the Invention

[0014] According to the operation method of the blast furnace and the auxiliary equipment of the blast furnace of the present invention, in the blast furnace operation in which solid carbon material is charged from the top of the blast furnace, by blowing the dry distillation gas generated when dry distilling woody biomass into the blast furnace, it is possible to perform the operation of the blast furnace that maintains the CO2 emission reduction effect by the solid carbon material and does not reduce the calorific value of B gas.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

[0016] In the following detailed description, many specific details will be described by way of example to provide a complete understanding of the present invention. However, it is clear that one or more embodiments can be implemented without such specific details. Also, for the sake of brevity, well-known structures and devices are shown in schematic form in the drawings.

[0017] <Regarding an embodiment of the operation method of the blast furnace of the present invention and blast furnace auxiliary equipment> In the operation method of the blast furnace of the present invention and blast furnace auxiliary equipment, an operation is performed in which ore and coke are alternately charged from the top of the blast furnace to form an ore layer and a coke layer. FIG. 1 is a flowchart for explaining an embodiment of the operation method of the blast furnace of the present invention and blast furnace auxiliary equipment. Hereinafter, an embodiment of the operation method of the blast furnace of the present invention and blast furnace auxiliary equipment will be described according to the flowchart of FIG. 1.

[0018] In the flowchart shown in FIG. 1, in the operation method of the blast furnace which is the object of the present invention, ore and coke are alternately charged from the top of the blast furnace 1 to form an ore layer and a coke layer in the blast furnace 1 for operation. Also, charcoal is produced by carbonizing wood in the charcoal furnace 2. Here, the wood is not particularly limited as long as it is a woody biomass that can generate solid carbonaceous material (charcoal) and carbonization gas by carbonization. For example, thinned wood or sawmill residues may be used. Also, the type of wood is not particularly limited, but for example, oak, oak, kunugi, or bamboo may be used. Charcoal may be produced from all of the wood, or a mixture of wood and coal may be carbonized to produce charcoal. The carbonization temperature is preferably 400 to 1000 °C. Since the strength of the charcoal increases as the carbonization temperature increases, the carbonization temperature is more preferably 800 to 1000 °C.

[0019] In the production of charcoal, the wood used changes into charcoal, pyrolysis gas, and distillate during the carbonization process. The yields of each substance are known to be, for example, when oak wood is pyrolyzed at about 1000 °C, about 25% by weight of charcoal, about 25% of pyrolysis gas, and about 50% of distillate. The yields of each substance vary depending on the type of charcoal and the pyrolysis temperature.

[0020] When the produced charcoal is charged from the top of the blast furnace 1 by replacing a part of the coke mixed in the ore layer, it is preferable because the reducibility of the ore is improved by the effect of the proximity arrangement of the ore and the charcoal. The charcoal ratio is preferably 150 kg / t or less. If the charcoal ratio exceeds 150 kg / t, the powder generated from the charcoal cannot be completely gasified in the furnace, and the powder accumulates in the furnace, particularly in the lower part of the furnace, which is an important factor in deteriorating the air permeability, so it is not preferable.

[0021] In this embodiment, the pyrolysis gas generated during charcoal production is cooled, dehydrated, and recovered. The recovered pyrolysis gas is composed mainly of gases such as CO, CO2, H2, and CH4. For example, the composition of the pyrolysis gas when oak wood is pyrolyzed at about 1000 °C is known to be, by weight, CO: 25 - 35%, CO2: 50 - 60%, H2: 2 - 5%, CH4: 5 - 10%, and hydrocarbons: 0 - 2%. The composition of the pyrolysis gas varies depending on the type of charcoal and the pyrolysis temperature.

[0022] In this embodiment, the recovered pyrolysis gas is blown into the furnace of the blast furnace 1 from the lance of the tuyere 3. It may be mixed with other reducing materials blown from the tuyere 3, such as pulverized coal, and blown in together, or may be blown in independently by providing another flow path. The blowing position of the pyrolysis gas does not necessarily have to be the tuyere 3, and it may be blown, for example, from the shaft part of the blast furnace 1.

[0023] At this time, similar to normal blast furnace operation, hot air is also blown in from tuyere 3. Further, pulverized coal may be blown in from the lance at tuyere 3 as a reduction aid. Since the temperature at the tip of the tuyere decreases due to the charging of charcoal and the blowing of dry distillation gas, in order to raise the temperature at the tip of the tuyere to a sufficient temperature, the temperature of the hot air is preferably 1000 °C or higher, more preferably 1100 °C or higher. The oxygen concentration of the hot air is preferably 21 - 35%. When the oxygen concentration is high, the temperature at the tip of the tuyere can be raised. However, if the oxygen concentration exceeds 35%, the temperature at the tip of the tuyere will rise too much, so it is preferably within this range. In an operation with a high oxygen concentration, the temperature of the top gas of the blast furnace decreases. In that case, the temperature of the top gas can be recovered by blowing high-temperature gas from the shaft part of the blast furnace.

[0024] In this embodiment, B gas is discharged from the top of blast furnace 1 and used in each process after pig iron making and pig iron making. When charcoal is charged, the calorific value of B gas decreases, but this problem can be solved by blowing the dry distillation gas generated during charcoal production into the blast furnace. Hydrocarbon components such as CO, CO2, H2, and CH4 contained in the blown dry distillation gas react with coke, etc. at the tip of the tuyere and change into a large amount of CO and H2. As a result, the amounts of CO and H2 flowing through the furnace of blast furnace 1 increase, and finally the CO and H2 concentrations of B gas discharged from the top of the blast furnace increase, and the calorific value of B gas can be increased. Further, in blast furnace 1, it is necessary to set the operating conditions so that the flame temperature (temperature at the tip of the tuyere) generated by the combustion of coke, pulverized coal, etc. at the tip of the tuyere is within an appropriate range. However, when dry distillation gas is blown in, it becomes possible to increase the oxygen concentration in the blast gas while keeping the temperature at the tip of the tuyere within the appropriate range. As a result, the amount of nitrogen flowing into the furnace from tuyere 3 can be reduced, and as the N2 concentration in B gas decreases, the CO and H2 concentrations of B gas further increase. Thereby, the calorific value of B gas can be recovered.

[0025] In this embodiment, it is preferable that the amount of pyrolysis gas blown in satisfies "pyrolysis gas ratio [kg / t] ≥ charcoal ratio [kg / t] × 0.35". This range is preferable because if the pyrolysis gas ratio [kg / t] is less than charcoal ratio [kg / t] × 0.35, the calorific value of the blast furnace gas may be lower than the calorific value of the B gas of a normal blast furnace that does not use charcoal.

[0026] As the pyrolysis gas ratio increases, the temperature at the tuyere tip decreases. Therefore, the pyrolysis gas ratio can be increased with the upper limit being the point where the temperature at the tuyere tip does not fall below the lower limit (2000 °C) of the appropriate operation range. The temperature at the tuyere tip can be calculated from the operating conditions (blast temperature, blast oxygen concentration, blast moisture content, pulverized coal ratio, etc.).

[0027] Normally, the amounts of charcoal and pyrolysis gas produced when wood is pyrolyzed result in a mass ratio of pyrolysis gas / charcoal of about 1. Therefore, it is preferable that pyrolysis gas ratio [kg / t] ≤ charcoal ratio [kg / t] × 1.0 because there is no risk of insufficient pyrolysis gas even during long-term operation. However, in cases where the pyrolysis gas yield is greater than the charcoal yield during production, or when only a small amount of the produced charcoal is used in the blast furnace, the pyrolysis gas ratio / charcoal ratio may exceed 1.

[0028] In the present invention, the coke ratio, pulverized coal ratio, charcoal ratio, and pyrolysis gas ratio refer to the masses [kg / t] of coke, pulverized coal, charcoal, and pyrolysis gas consumed in the blast furnace when producing 1 t of hot metal.

[0029] <For other embodiments of the operation method of the blast furnace of the present invention and the auxiliary equipment of the blast furnace> Figure 2 is a flowchart for explaining other embodiments of the operation method of the blast furnace of the present invention and the auxiliary equipment of the blast furnace. In other embodiments of the present invention shown in Figure 2, a CO2 separation device 4 is added to the configuration shown in Figure 1.

[0030] In this embodiment, the CO2 separation device 4 provided between the blast furnace 1 and the charcoal furnace 2 separates and removes CO2 from the pyrolysis gas recovered in the charcoal furnace 2, and blows the pyrolysis gas (mainly CO, H2, CH4, hydrocarbons) after CO2 separation and removal into the blast furnace 1.

[0031] In this embodiment, the following effects can be obtained. Specifically, if the carbonization gas is directly injected from the tuyere 3 as in the embodiment shown in FIG. 1, the CO2 contained in the carbonization gas may react with the coke (C + CO2 = 2CO) and consume a portion of the coke. In this case, the effect of reducing the reducing agent consumption due to the reducing gas components (CO, H2) in the carbonization gas is canceled out, and the reducing agent consumption (CO2 emission amount) becomes almost the same as before the carbonization gas injection. However, as in this embodiment, by removing CO2 from the carbonization gas in advance to obtain a CO2-free reducing gas and then injecting it into the blast furnace, the effect of further reducing the reducing agent ratio by the carbonization gas injection can be achieved. In addition, CO2 emissions can be further reduced.

[0032] In the case where CO2 is separated and removed from the carbonized gas before being injected into the blast furnace as in this embodiment, the amount of carbonized gas injected after CO2 separation and removal is preferably "carbonized gas ratio [kg / t] ≥ charcoal ratio [kg / t] × 0.4". This is because if the carbonized gas ratio [kg / t] is less than the charcoal ratio [kg / t] × 0.4, the calorific value of the blast furnace gas may be less than the calorific value of gas B of a normal blast furnace. [Example]

[0033] <Example 1: Injecting carbonized gas directly into a blast furnace> Regarding the case of blowing dry distillation gas directly into the blast furnace, in the blast furnace operation of charging charcoal from the top of the blast furnace, the influence of dry distillation gas injection on the calorific value of B gas was investigated by heat substance balance calculation. Specifically, as shown in Table 1 below, with other conditions being the same, the coke ratio, pulverized coal ratio, charcoal ratio, dry distillation gas ratio, dry distillation gas ratio / charcoal ratio, and input carbon amount (carbon neutral removal, hereinafter abbreviated as CN removal) were changed, and blast furnace operations were carried out for Comparative Examples 1-5 and Inventive Examples 1-4. Then, for each of Comparative Examples 1-5 and Inventive Examples 1-4, the CO2 emission amount, calorific value of B gas, oxygen concentration, and blowing temperature were determined. Since the CO2 emission amount tends to decrease as the charcoal ratio increases, in order to clarify the effect of dry distillation gas injection, the CO2 emission amount and calorific value of B gas were evaluated under the condition of the same charcoal ratio with and without dry distillation gas. In order to show that the present invention holds regardless of the value of the charcoal ratio, under the condition of a charcoal ratio of about 58 kg / t (Comparative Example 2, Comparative Example 3, Inventive Example 1, Inventive Example 2), a charcoal ratio of about 134 kg / t (Comparative Example 4, Inventive Example 3), and a charcoal ratio of about 12 kg / t (Comparative Example 5, Inventive Example 4), the CO2 emission amount and calorific value of B gas were evaluated with and without dry distillation gas injection, respectively.

[0034] In Table 1, Comparative Example 1 shows the results of a normal blast furnace operation with a coke ratio of 360 kg / t and a pulverized coal ratio of 160 kg / t without charging charcoal or injecting dry distillation gas. Also, Comparative Examples 2, 4, and 5 show the results of blast furnace operations with only charcoal charging and no dry distillation gas injection, respectively. Furthermore, Comparative Example 3 shows the results of a blast furnace operation in the case of increasing the reduction material ratio (here, the pulverized coal ratio) in order not to reduce the calorific value of B gas in the operation of charging only charcoal.

[0035]

Table 1

[0036] Based on the results in Table 1, as Evaluation 1, in the examples with approximately the same charcoal ratio, whether the CO₂ emissions are approximately the same as those in the example with only charcoal charged was shown. Specifically, for Comparative Example 3, Invention Example 1, and Invention Example 2, the determination was made with respect to the CO₂ emissions of Comparative Example 2; for Invention Example 3, the determination was made with respect to the CO₂ emissions of Comparative Example 4; and for Invention Example 4, the determination was made with respect to the CO₂ emissions of Comparative Example 5. Also, based on the results in Table 1, as Evaluation 2, for Comparative Examples 2 - 5 and Invention Examples 1 - 4, whether the calorific value of Gas B is equal to or higher than that of Comparative Example 1 where normal blast furnace operation without charging charcoal or blowing dry distillation gas was carried out was shown. If it is equal to or higher, it was marked as ○; if it is less, it was marked as ×.

[0037] From the results in Table 1, it can be seen that in the operation of only charging charcoal without blowing dry distillation gas, the CO₂ emissions decrease according to the charcoal ratio, but the calorific value of Gas B decreases (Comparative Examples 2, 4, 5). Also, in the operation of charging charcoal, if the reduction material ratio (here, the pulverized coal ratio) is increased to prevent the calorific value of Gas B from decreasing, it can be seen that the CO₂ emissions increase and the CO₂ reduction effect weakens (Comparative Example 3).

[0038] On the other hand, when blowing dry distillation gas in the operation of charging charcoal, it can be seen that as the dry distillation gas ratio increases, the calorific value of Gas B increases, and when the dry distillation gas ratio / charcoal ratio is 0.35 or more, the calorific value of Gas B recovers to the base (Comparative Example 1) or more (Invention Examples 1, 2). At this time, in Invention Examples 1 and 2, it can be seen that a low CO₂ emission level approximately equivalent to that in the case of only charging charcoal without blowing dry distillation gas (Comparative Example 2) can be maintained, and the calorific value of Gas B can be increased to the level equivalent to that of a normal blast furnace while maintaining the CO₂ reduction effect by charging charcoal.

[0039] Also, even when the charcoal ratio is high, it can be seen that by performing dry distillation gas blowing with a dry distillation gas ratio / charcoal ratio of 0.35 or more, the calorific value of Gas B can be recovered to the base (Comparative Example 1) or more while maintaining the CO₂ reduction effect by charging charcoal (Invention Example 3). It can be understood that this is the same even when the charcoal ratio is low (Invention Example 4).

[0040] <Example 2: Case of Injecting into a Blast Furnace after Separating and Removing CO2 from Coke Oven Gas> Regarding the case of injecting into a blast furnace after separating and removing CO2 from coke oven gas, the influence of coke oven gas injection on the calorific value of B gas in the blast furnace operation of charging charcoal from the top of the blast furnace was investigated by heat material balance calculation. Specifically, as shown in Table 2 below, with other conditions being the same, the coke ratio, pulverized coal ratio, charcoal ratio, coke oven gas ratio, coke oven gas ratio / charcoal ratio, and input oxygen amount (CN removal) were changed, and blast furnace operations were carried out for Comparative Examples 1-5 and Inventive Examples 1-4. Then, for each of Comparative Examples 11-15 and Inventive Examples 11-14, the CO2 emission amount, calorific value of B gas, oxygen concentration, and blast temperature were determined.

[0041] In Table 2, Comparative Example 11 shows the results of a normal blast furnace operation with a coke ratio of 360 kg / t and a pulverized coal ratio of 160 kg / t without charging charcoal or injecting coke oven gas. Also, Comparative Examples 12, 14, and 15 show the results of blast furnace operations with only charcoal charging and no coke oven gas injection, respectively. Furthermore, Comparative Example 13 shows the results of an operation with only charcoal charging and an increased reduction material ratio (here, the pulverized coal ratio) to prevent a decrease in the calorific value of B gas.

[0042]

Table 2

[0043] Based on the results in Table 2, as Evaluation 1, in examples with approximately the same charcoal ratio, whether the CO2 emission amount is approximately the same as that in the example with only charcoal charging was shown as ○ for the same cases and × for other cases. Specifically, for Comparative Example 13, Inventive Example 11, and Inventive Example 12, judgments were made regarding the CO2 emission amount of Comparative Example 12. For Inventive Example 13, a judgment was made regarding the CO2 emission amount of Comparative Example 14, and for Inventive Example 14, a judgment was made regarding the CO2 emission amount of Comparative Example 15. Also, based on the results in Table 2, as Evaluation 2, for Comparative Examples 12-15 and Inventive Examples 11-14, whether the calorific value of B gas is equal to or higher than the calorific value of B gas in Comparative Example 11, which was a normal blast furnace operation without charging charcoal or injecting coke oven gas, was shown as ○ for the above cases and × for cases below.

[0044] From the results in Table 2, similar to the results of Example 1, it can be seen that in the operation of only charging charcoal and not blowing pyrolysis gas, the CO₂ emission decreases according to the charcoal ratio, but the calorific value of Gas B decreases (Comparative Examples 12, 14, 15). Also, in the operation of charging charcoal, when the reduction material ratio (here, the fine coal ratio) is increased to not reduce the calorific value of Gas B, it can be seen that the CO₂ emission increases and the CO₂ reduction effect weakens (Comparative Example 13).

[0045] On the other hand, when the pyrolysis gas from which CO₂ is separated and removed is blown into the blast furnace during the operation of charging charcoal, it can be seen that the calorific value of Gas B increases with the increase in the pyrolysis gas ratio, and when the pyrolysis gas ratio / charcoal ratio becomes 0.4 or more, the calorific value of Gas B recovers to the base (Comparative Example 11) or more (Inventive Examples 11, 12). At this time, in Inventive Examples 11 and 12, it can be seen that the CO₂ emission further decreases by blowing pyrolysis gas compared to when only charging charcoal.

[0046] Also, even when the charcoal ratio is high, by blowing the pyrolysis gas after CO₂ removal so that the pyrolysis gas ratio / charcoal ratio becomes 0.4 or more, it can be seen that the CO₂ emission can be further reduced while recovering the calorific value of Gas B to the base (Comparative Example 11) or more (Inventive Example 13). It can be understood that this is the same even when the charcoal ratio is low (Inventive Example 14).

Explanation of Symbols

[0047] 1 Blast furnace 2 Charcoal furnace 3 Tuyere 4 CO₂ separation device

Claims

1. In the operation of a blast furnace in which solid carbonaceous material is charged from the top of the blast furnace, the operation method of the blast furnace having a charging step of charging the solid carbonaceous material produced by carbonizing woody biomass into the blast furnace and a blowing step of blowing the carbonization gas into the blast furnace.

2. In the blowing step, after separating and removing CO from the retort gas ２ the retort gas from which CO has been separated and removed is blown into the blast furnace. The method for operating a blast furnace according to claim 1 ２ ​

3. The operation method of the blast furnace according to claim 1 or 2, wherein in the blowing step, the blowing amount of the carbonization gas is set according to the amount of the solid carbonaceous material charged into the blast furnace.

4. The operation method of the blast furnace according to claim 3, wherein the blowing amount of the carbonization gas satisfies the following formula (1). Carbonization gas ratio [kg / t] ≥ Solid carbonaceous material ratio [kg / t] × 0.35... (1)

5. The operation method of the blast furnace according to claim 3, wherein the blowing amount of the carbonization gas satisfies the following formula (2). Carbonization gas ratio [kg / t] ≥ Solid carbonaceous material ratio [kg / t] × 0.40... (2)

6. Ancillary equipment for a blast furnace, comprising a charcoal furnace for producing solid carbonaceous material and carbonization gas from woody biomass, a solid carbonaceous material introduction path for introducing the solid carbonaceous material generated from the charcoal furnace to the top of the blast furnace, and a carbonization gas introduction path for introducing the carbonization gas into the blast furnace.

7. CO is provided in the carbonization gas introduction path ２ The blast furnace auxiliary equipment according to claim 6, comprising a separation device.

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