WO2021107091A1 - Blast furnace operation method - Google Patents

Blast furnace operation method Download PDF

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Publication number
WO2021107091A1
WO2021107091A1 PCT/JP2020/044217 JP2020044217W WO2021107091A1 WO 2021107091 A1 WO2021107091 A1 WO 2021107091A1 JP 2020044217 W JP2020044217 W JP 2020044217W WO 2021107091 A1 WO2021107091 A1 WO 2021107091A1
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Prior art keywords
amount
gas
hydrogen
temperature
containing gas
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PCT/JP2020/044217
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French (fr)
Japanese (ja)
Inventor
酒井　博
中野　薫
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日本製鉄株式会社
Ｊｆｅスチール株式会社
株式会社神戸製鋼所
日鉄エンジニアリング株式会社
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Application filed by 日本製鉄株式会社, Ｊｆｅスチール株式会社, 株式会社神戸製鋼所, 日鉄エンジニアリング株式会社 filed Critical 日本製鉄株式会社
Priority to CA3161120A priority Critical patent/CA3161120A1/en
Priority to AU2020393659A priority patent/AU2020393659B2/en
Priority to JP2021561541A priority patent/JP7297091B2/en
Priority to US17/779,384 priority patent/US20220403477A1/en
Priority to BR112022010162A priority patent/BR112022010162A2/en
Priority to EP20894471.0A priority patent/EP4067510A4/en
Priority to CN202080083068.4A priority patent/CN114787391B/en
Priority to KR1020227020856A priority patent/KR20220099573A/en
Publication of WO2021107091A1 publication Critical patent/WO2021107091A1/en

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B7/00—Blast furnaces
    • C21B7/16—Tuyéres
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B5/00—Making pig-iron in the blast furnace
    • C21B5/06—Making pig-iron in the blast furnace using top gas in the blast furnace process
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B7/00—Blast furnaces
    • C21B7/007—Controlling or regulating of the top pressure
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B5/00—Making pig-iron in the blast furnace
    • C21B5/001—Injecting additional fuel or reducing agents
    • C21B2005/005—Selection or treatment of the reducing gases

Definitions

  • the present invention relates to a method of operating a blast furnace.
  • the present application claims priority based on Japanese Patent Application No. 2019-216568 filed in Japan on November 29, 2019 and Japanese Patent Application No. 2020-92467 filed in Japan on May 27, 2020. The contents are used here.
  • the blast furnace method is the mainstream of the pig iron manufacturing process.
  • iron-based raw materials for blast furnaces raw materials containing iron oxide, mainly sintered ore, hereinafter simply referred to as "iron-based raw materials”
  • coke are alternately and layered in the blast furnace from the top of the blast furnace.
  • hot air is blown into the blast furnace from the tuyere at the bottom of the blast furnace.
  • the hot air reacts with the pulverized coal blown together with the hot air and the coke in the blast furnace to generate a high-temperature reducing gas (mainly CO gas in this case). That is, the hot air gasifies coke and pulverized coal.
  • a high-temperature reducing gas mainly CO gas in this case
  • the reducing gas rises in the blast furnace and reduces the iron-based raw material while heating it.
  • the iron-based raw material is heated and reduced by the reducing gas while descending in the blast furnace. After that, the iron-based raw material is melted and dropped in the blast furnace while being further reduced by coke.
  • the iron-based raw material is finally stored in the hearth as hot metal (pig iron) containing a little less than 5% by mass of carbon.
  • the hot metal in the hearth is taken out from the hot metal outlet and used for the next steelmaking process. Therefore, in the blast furnace method, a charcoal material such as coke and pulverized coal is used as a reducing material.
  • the reducing agent has the role of raising the temperature of the charged material as heat in the furnace and the role of reducing the iron-based raw material in the furnace.
  • the reduction reaction in the furnace can be expressed by various reaction formulas.
  • the direct reduction reaction by coke (reaction formula: FeO + C ⁇ Fe + CO) is an endothermic reaction accompanied by a large endothermic reaction. Therefore, it is important to prevent this reaction from occurring as much as possible in order to reduce the ratio of reducing agents.
  • this direct reduction reaction occurs in the lower part of the blast furnace, if the iron-based raw material can be sufficiently reduced with a reducing gas such as CO and H 2 by the time the iron-based raw material reaches the lower part of the furnace, the direct reduction reaction will occur.
  • the target iron-based raw materials can be reduced.
  • a reducing gas with the hot air from tuyere H 2 gas, COG (Cokes Oven Gas), natural gas, city gas, etc.
  • H 2 gas, COG Cokes Oven Gas
  • natural gas city gas, etc.
  • a technique for improving the reducing gas potential in the furnace by injecting When the reducing gas becomes a carbon-containing reducing gas (a reducing gas containing carbon atoms in the molecular structure of the gas, for example, a hydrocarbon gas), the carbon atoms in the carbon-containing gas become CO gas in the blast furnace, and the iron-based raw material is reduced. To do.
  • the reducing gas becomes hydrogen gas (H 2 gas)
  • the hydrogen gas reduces the iron-based raw material.
  • carbon and hydrogen mean carbon atoms and hydrogen atoms, respectively.
  • the present invention has been made in view of the above problems, and an object of the present invention is to blow a high-concentration hydrogen-containing gas as a reduction gas blown from a tuyere while maintaining stable blast furnace operation. It is an object of the present invention to provide a new and improved method of operating a blast furnace capable of increasing the filling amount and further reducing the CO 2 emission.
  • a high-concentration hydrogen-containing gas containing 80 mol% or more of hydrogen gas is blown into a high-concentration hydrogen-containing gas at a temperature of room temperature or higher and 300 ° C. or lower. and conditions blowing amount of the hydrogen gas in the high concentration hydrogen-containing gas is less than 200 Nm 3 / t or more 500 Nm 3 / t, and the blowing temperature of the high concentration hydrogen-containing gas is 300 ° C. ultra 600 ° C.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 110 Nm under the condition that the amount of hydrogen gas blown is 125 Nm 3 / t or more, the temperature of the high-concentration hydrogen-containing gas is more than 900 ° C. and 1200 ° C. or less.
  • the blowing temperature of the high-concentration hydrogen-containing gas is room temperature or higher and 300 ° C. or lower, and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 200 Nm 3 / t or higher and 300 Nm 3 / t or lower. May be good.
  • the blowing temperature of the high-concentration hydrogen-containing gas is more than 300 ° C. and 600 ° C. or less, and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 145 Nm 3 / t or more and 600 Nm 3 / t or less. May be good.
  • the temperature in front of the tuyere may be 2050 ° C. or lower.
  • the temperature in front of the tuyere may be more than 2050 ° C and 2150 ° C or less.
  • the temperature in front of the tuyere may be more than 2150 ° C and 2250 ° C or less.
  • blowing temperature of the high-concentration hydrogen-containing gas may be more than 600 ° C and 1400 ° C or less.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas may be 1000 Nm 3 / t or less.
  • the temperature before the tuyere is set to 2050 ° C. It may be as follows.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas and carbon when the blow-in temperature of the high-concentration hydrogen-containing gas containing 80 mol% or more of hydrogen gas is a predetermined value.
  • the hydrogen in high-concentration hydrogen-containing gas which is the correlation with the carbon consumption parameter related to the consumption amount, is obtained in advance for each tuyere temperature, and the carbon consumption is reduced compared to the current operation.
  • a method for operating a blast furnace is characterized in that the amount of gas blown is determined based on the amount of blown-carbon consumption parameter correlation, and high-concentration hydrogen-containing gas is blown from the tuyere at the determined amount of blown hydrogen. Provided.
  • the hydrogen gas injection amount-carbon consumption parameter correlation in the high-concentration hydrogen-containing gas may be obtained for each injection temperature of the high-concentration hydrogen-containing gas.
  • the blowing amount which is the correlation between the blowing amount of the hydrogen gas in the high-concentration hydrogen-containing gas and the change amount of the pressure loss with respect to the base operation In a high-concentration hydrogen-containing gas in which the correlation of the amount of change in pressure loss is obtained in advance for each tuyere temperature, the carbon consumption is reduced compared to the current operation, and the amount of change in pressure loss is within a predetermined range.
  • the amount of hydrogen gas blown in may be determined based on the blown amount-carbon consumption parameter correlation and the blown amount-pressure loss change amount correlation.
  • the blowing amount of the hydrogen gas in the high-concentration hydrogen-containing gas is correlated with the change amount of the furnace top gas temperature with respect to the base operation.
  • the correlation between the amount and the amount of change in the temperature of the top gas is obtained in advance for each tuyere temperature, and the carbon consumption is reduced compared to the current operation, and the amount of change in the top gas temperature is within the specified range.
  • the blown amount of hydrogen gas in the high-concentration hydrogen-containing gas may be determined based on the blown amount-carbon consumption parameter correlation and the blown amount-furnace top gas temperature change amount correlation.
  • the amount of high-concentration hydrogen-containing gas blown from the tuyere is increased while maintaining stable blast furnace operation, and the amount of CO 2 emissions is further increased. It is possible to reduce it.
  • the numerical range represented by using “-" means a range including the numerical values before and after "-" as the lower limit value and the upper limit value.
  • the "reducing agent ratio" is the total mass of the reducing agents required to produce 1 ton of hot metal. Therefore, the reducing agent ratio is basically the total mass of coke and pulverized coal required to produce 1 ton of hot metal, and the mass of the carbon-containing reducing gas in the high-concentration hydrogen-containing gas is included in the reducing agent ratio. It is treated as something that cannot be done.
  • the "carbon consumption intensity (Input C)” is the carbon required to produce 1 ton of hot metal (that is, the amount of carbon consumed per ton of hot metal).
  • the present inventor has focused on a high-concentration hydrogen-containing gas as a reducing gas.
  • the high-concentration hydrogen-containing gas in the present embodiment means a gas containing 80 mol% or more of hydrogen gas (mol% of hydrogen gas with respect to the total amount of substances of all the gases constituting the high-concentration hydrogen-containing gas). .. Pure hydrogen gas (gas having a hydrogen gas concentration of 100 mol%) is included in the high-concentration hydrogen-containing gas.
  • the present inventor paid attention to the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas (hereinafter, also simply referred to as the amount of blown hydrogen) and the blowing temperature of the high-concentration hydrogen-containing gas.
  • the reduction reaction of an iron-based raw material by hydrogen gas in a high-concentration hydrogen-containing gas is an endothermic reaction.
  • the present inventors have conducted a detailed study on the above matters. Specifically, the composition of various gases such as hydrogen gas and CO gas in the high-concentration hydrogen-containing gas and the reduction reaction rate of the high-concentration hydrogen-containing gas at various blowing temperatures are grasped, and the reduction of these gases is performed. The effect of the furnace temperature, which changes due to the reaction heat, on the reduction reaction rate and the effect of the gas composition, which changes due to the reduction reaction, on the reduction reaction rate are grasped, and then the amount of heat is such that the reduction reaction rate does not decrease. Grasp was done for the entire reactor.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas when the reduction rate of the carbon consumption intensity is relaxed and starts to decrease differs depending on the blowing temperature of the high-concentration hydrogen-containing gas.
  • the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C.
  • the reduction rate Input ⁇ C of the carbon consumption intensity tends to increase as the blowing amount increases.
  • the reduction rate of carbon consumption intensity, Input ⁇ C becomes, for example, 7% or more.
  • CO 2 emissions can be significantly reduced by blowing the amount of high-concentration hydrogen-containing gas blown into the blast furnace, which is determined according to the amount of hydrogen gas blown in this appropriate range.
  • the reduction rate of carbon consumption intensity during operation of the blast furnace can be set to 7% or more, and CO 2 emissions can be significantly reduced.
  • the high-concentration hydrogen-containing gas is a gas containing 80 mol% or more of hydrogen gas as described above.
  • the high-concentration hydrogen-containing gas includes pure hydrogen gas.
  • the high-concentration hydrogen-containing gas includes gases other than hydrogen gas, such as the above-mentioned carbon-containing reducing gas (for example, hydrocarbon gas), CO gas, CO 2 gas, H 2 O gas, N 2 gas and the like. May be good. However, the total concentration of other gases is less than 20 mol%.
  • Gases having a total concentration of 20 mol% or more of other gases are not included in the high-concentration hydrogen-containing gas in the present embodiment. This is because when the concentration of the other gas is 20 mol% or more, the amount of CO 2 gas reduction is greatly reduced.
  • the concentration of the other gas is 20 mol% or more, the amount of CO 2 gas reduction is greatly reduced.
  • hydrocarbon gas, CO 2 gas, and H 2 O gas cause an endothermic reaction when they are decomposed at the tuyere tip, so that the reduction efficiency in the blast furnace is lowered. Therefore, the amount of iron-based raw materials that reach the lower part of the blast furnace without being reduced increases. Therefore, the amount of direct reduction reaction by coke increases. Therefore, since a large amount of reducing agent is required to maintain the temperature in the blast furnace, the amount of CO 2 gas reduction is greatly reduced.
  • the blowing temperature of the high-concentration hydrogen-containing gas is determined within the range of room temperature or higher.
  • FIG. 1 is a diagram for explaining the blowing temperature.
  • the temperature of the high-concentration hydrogen-containing gas is adjusted, for example, in a gas tank 3 provided with a heater 5. That is, the high-concentration hydrogen-containing gas is heated by the heater 5 in the gas tank 3 or remains unheated at room temperature, and the tuyere 2 for blowing hot air provided in the lower part of the blast furnace 1 is provided. Will be sent to.
  • the high-concentration hydrogen-containing gas sent to the tuyere 2 can be blown into the blast furnace 1 from the tuyere 2.
  • the high-concentration hydrogen-containing gas sent to the tuyere 2 is mixed (merged) with the hot air generated in the hot air furnace 4 and then blown into the blast furnace 1 from the tuyere 2.
  • the blowing temperature is the temperature of the high-concentration hydrogen-containing gas immediately before being mixed with the hot air when it is blown into the blast furnace 1 from the tuyere 2.
  • the set temperature of the heater 5 can be set as the blowing temperature. ..
  • the temperature of the high-concentration hydrogen-containing gas rises due to the mixing of the hot air and the high-concentration hydrogen-containing gas, but the temperature at this time is not the blowing temperature in the present embodiment. Further, although Patent Document 1 describes the blowing temperature, the blowing temperature of Patent Document 1 is different from the blowing temperature in the present embodiment.
  • FIG. 2 is a graph showing the correlation between the amount of pure hydrogen gas blown at room temperature and the reduction rate of carbon consumption intensity Input ⁇ C for each tuyere temperature Tf. This graph is obtained by blast furnace operation simulation. Details will be described in Examples, but here, Koji TAKATANI, Takanobu INADA, Yutaka UJISAWA, "Three-dimensional Dynamic Simulation for Blast Furnace", ISIJ International. 39 (1999), No. 1, p. The so-called "blast furnace mathematical model” shown in 15-22 and the like was used.
  • This blast furnace mathematical model roughly defines a plurality of meshes (small regions) by dividing the internal region of the blast furnace into the height direction, the radial direction, and the circumferential direction, and simulates the behavior of each mesh. is there.
  • the simulation conditions were the same as in the examples described later.
  • the reduction rate of carbon consumption intensity can be set to 7% or more, for example. ..
  • the reduction rate of carbon consumption intensity Input ⁇ C is preferably 8% or more.
  • the "room temperature" in the present embodiment means a non-heated state, and specifically, the temperature is 5 ° C. or higher and 35 ° C. or lower.
  • FIG. 3 is a graph showing the correlation between the amount of pure hydrogen gas blown at 300 ° C. and the reduction rate of carbon consumption intensity Input ⁇ C for each tuyere temperature Tf.
  • FIG. 4 is a graph showing the correlation between the amount of pure hydrogen gas blown at 350 ° C. and the reduction rate Input ⁇ C of the carbon consumption intensity.
  • FIG. 5 is a graph showing the correlation between the amount of pure hydrogen gas blown at 600 ° C.
  • FIG. 6 is a graph showing the correlation between the amount of pure hydrogen gas blown at 650 ° C. and the reduction rate Input ⁇ C of the carbon consumption intensity.
  • FIG. 7 is a graph showing the correlation between the amount of pure hydrogen gas blown at 900 ° C. and the reduction rate of carbon consumption intensity Input ⁇ C for each tuyere temperature Tf.
  • FIG. 8 is a graph showing the correlation between the amount of pure hydrogen gas blown at 950 ° C. and the reduction rate Input ⁇ C of the carbon consumption intensity.
  • FIG. 9 is a graph showing the correlation between the amount of pure hydrogen gas blown at 1200 ° C.
  • FIG. 10 is a graph showing the correlation between the amount of pure hydrogen gas blown at 1250 ° C. and the reduction rate Input ⁇ C of the carbon consumption intensity.
  • the blowing temperature of the high-concentration hydrogen-containing gas it is preferable to increase the blowing temperature of the high-concentration hydrogen-containing gas. Specifically, it is preferable to determine the blowing temperature in the range of more than 300 ° C., more preferably in the range of more than 600 ° C., and more preferably in the range of more than 900 ° C.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is determined.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is the flow rate per ton of the hot metal of the hydrogen gas in the high-concentration hydrogen-containing gas blown into the blast furnace from the tuyere, and the unit is Nm 3 /. t.
  • the high-concentration hydrogen-containing gas is pure hydrogen gas
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is equal to the amount of high-concentration hydrogen-containing gas blown.
  • the high-concentration hydrogen-containing gas is a mixed gas containing a gas other than hydrogen gas
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is in units of mol%. It is the amount obtained by multiplying the amount by the ratio of hydrogen gas.
  • high-concentration hydrogen is obtained from the value indicated by the flow meter provided at the outlet of the high-concentration hydrogen-containing gas supply source (for example, a gas tank) and the ratio of hydrogen gas in the high-concentration hydrogen-containing gas in units of mol%. Calculate the amount of hydrogen gas blown into the contained gas.
  • the blowing amount is determined for each case according to the blowing temperature of the high-concentration hydrogen-containing gas. Specifically, when the blowing temperature is room temperature to 300 ° C., the blowing amount of hydrogen gas in the high-concentration hydrogen-containing gas is determined within the range of 200 to 500 Nm 3 / t. On the other hand, when the blowing temperature is more than 300 ° C. and 600 ° C. or lower, the blowing amount of hydrogen gas in the high-concentration hydrogen-containing gas is determined within the range of 145 Nm 3 / t. When the blowing temperature of the high-concentration hydrogen-containing gas is more than 600 ° C. and 900 ° C.
  • the blowing amount of the high-concentration hydrogen-containing gas is determined within the range of 125 Nm 3 / t or more.
  • the blowing temperature of the high-concentration hydrogen-containing gas is more than 900 ° C. and 1200 ° C. or lower, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is determined within the range of 110 Nm 3 / t or more.
  • the blowing temperature of the high-concentration hydrogen-containing gas exceeds 1200 ° C., the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is determined within the range of 100 Nm 3 / t or more.
  • the suitable blowing amount differs slightly depending on the blowing temperature.
  • the high-concentration hydrogen-containing gas is pure hydrogen gas
  • the high-concentration hydrogen-containing gas contains a gas other than hydrogen gas. Even in this case, the correlation between the blowing temperature of the high-concentration hydrogen-containing gas and the suitable blowing amount does not change.
  • the reduction rate of carbon consumption intensity, Input ⁇ C can be set to 7% or more. It will be possible.
  • the high-concentration hydrogen-containing gas becomes pure hydrogen gas
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is the amount of high-concentration hydrogen-containing gas blown, but the high-concentration hydrogen-containing gas is hydrogen.
  • this value is the amount obtained by multiplying the amount of high-concentration hydrogen-containing gas blown by the ratio of hydrogen gas (mol%).
  • the reduction reaction of iron-based raw materials with hydrogen gas (that is, hydrogen reduction reaction) is an endothermic reaction. Therefore, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas exceeds 300 Nm 3 / t, it is considered that such an endothermic reaction occurs frequently in the furnace and the temperature inside the furnace drops. Then, it is considered that such a decrease in the temperature inside the furnace reduces the reduction efficiency by the reducing gas containing hydrogen gas. In order to prevent such a decrease in reducing efficiency, it is necessary to increase the ratio of reducing materials to carry out the operation. Therefore, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas exceeds 300 Nm 3 / t, the reduction rate Input ⁇ C of the carbon consumption intensity starts to decrease.
  • the blowing temperature is room temperature to 300 ° C.
  • the reduction rate Input ⁇ C of the carbon consumption intensity can be set to 8% or more.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 0 Nm in the base operation. Increasing from 3 / t increases the reduction rate of carbon consumption intensity Input ⁇ C. When the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 145 Nm 3 / t or more, the reduction rate Input ⁇ C of the carbon consumption intensity is 7% or more.
  • the blowing temperature of the high-concentration hydrogen-containing gas is 600 ° C., as shown in FIG.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is about 600 Nm 3 / t, and the reduction rate of carbon consumption intensity Imput. ⁇ C is saturated.
  • the blowing temperature of the high-concentration hydrogen-containing gas is 350 ° C., as shown in FIG. 4, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is about 300 Nm 3 / t, the carbon consumption intensity is the basic unit.
  • the reduction rate of Imput ⁇ C peaks and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas further increases, the reduction rate of carbon consumption intensity Imput ⁇ C starts to decrease.
  • the tuyere temperature Tf should be maintained at 2200 ° C. when the blowing amount of the hydrogen gas in the high-concentration hydrogen-containing gas exceeds 600 Nm 3 / t. Can be difficult.
  • the tuyere temperature Tf is often set to about 2200 ° C., and when it is difficult to maintain the tuyere temperature Tf at 2200 ° C., the operation is largely different from the operating conditions of the conventional blast furnace operation. The conditions will be changed.
  • the reason why the reduction rate Input ⁇ C of the carbon consumption intensity starts to decrease when the blowing temperature of the high-concentration hydrogen-containing gas is 350 ° C. is the same as the above.
  • the blowing temperature of the high-concentration hydrogen-containing gas is 600 ° C.
  • the reduction rate Input ⁇ C of the carbon consumption intensity does not turn to decrease in the range of the blowing amount up to 700 Nm 3 / t.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is about 600 Nm 3 / t, the effect of reducing the carbon consumption intensity is saturated.
  • the blowing temperature is more than 350 ° C and 600 ° C or less, the sensible heat of Bosch gas is larger.
  • the reduction rate Input ⁇ C of the carbon consumption intensity is saturated. Further, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 300 to 600 Nm 3 / t, the reduction rate of carbon consumption intensity is 10% or more.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is increased from 0 Nm 3 / t in the base operation.
  • the reduction rate of carbon consumption intensity, Input ⁇ C will increase.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is within the range of 125 Nm 3 / t or more, the reduction rate of carbon consumption intensity is 7% or more.
  • the reduction rate of carbon consumption intensity is 10% or more.
  • FIG. 7 shows the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas and the reduction rate of the carbon consumption intensity when the blowing temperature of the high-concentration hydrogen-containing gas (here, pure hydrogen gas) is 900 ° C.
  • the reduction reaction with hydrogen gas is an endothermic reaction
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas increases to some extent, the reduction rate of carbon consumption intensity Input ⁇ C starts to decrease.
  • the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C.
  • the sensible heat of the Bosch gas generated in the blast furnace becomes very high, so that the reaction heat required for the reduction reaction can be covered. Therefore, even if the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas increases, the reduction rate of carbon consumption intensity Input ⁇ C does not start to decrease, but is considered to continue to increase.
  • Such behavior is observed when the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C.
  • the upper limit of the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is not particularly set.
  • the rate of decrease in carbon consumption intensity decreases, and the rate of increase in Input ⁇ C decreases.
  • the effect is expected to level off.
  • the amount of blown water at this time is assumed to be approximately 1000 Nm 3 / t. Therefore, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas may be 1000 Nm 3 / t or less.
  • the blowing temperature is more than 900 ° C and 1200 ° C or less
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is increased from 0 Nm 3 / t in the base operation.
  • the reduction rate of carbon consumption intensity Output ⁇ C
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is within the range of 110 Nm 3 / t or more
  • the reduction rate of carbon consumption intensity is 7% or more.
  • the reduction rate of carbon consumption intensity is 10% or more.
  • FIG. 9 shows the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas and the reduction rate of the carbon consumption intensity when the blowing temperature of the high-concentration hydrogen-containing gas (here, pure hydrogen gas) is 1200 ° C. Although it is a graph showing the correlation with C, the same tendency as in FIG.
  • the upper limit of the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is not particularly set.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas reaches about 1000 Nm 3 / t, the effect of reducing the carbon consumption intensity is expected to peak, so hydrogen in the high-concentration hydrogen-containing gas
  • the amount of gas blown may be 1000 Nm 3 / t or less.
  • the pressure loss is the difference between the pressure at the tuyere tip (in front of the tuyere), in other words, the pressure inside the furnace at the outlet of the tuyere and the pressure at the top of the furnace, excluding the pipe pressure loss from the blower to the tuyere tip. Value.
  • the pressure loss is measured by a pressure gauge installed on the furnace wall.
  • FIG. 14 in the blast furnace operation under the high hydrogen concentration condition as in the present embodiment, the gas viscosity and the gas density in the furnace are significantly lowered, so that the pressure loss when the coke ratio is reduced is increased. Concerns about the rise have been resolved, and the pressure loss is such that there is no problem with stable operations in actual operations.
  • FIG. 14 is a graph showing the correlation between the amount of pure hydrogen gas blown at 1200 ° C. and the amount of change in the pressure loss in the furnace when the temperature in front of the tuyere reaches 2100 ° C., which was obtained by blast furnace operation simulation. It is something that can be done.
  • the pressure loss in normal operation is about 85 kPa as a guide. According to FIG. 14, it can be seen that the pressure loss is less than 85 kPa under the operating conditions of the present embodiment.
  • the carbon consumption source is increased.
  • Unit reduction rate Input ⁇ C increases.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is within the range of 100 Nm 3 / t or more, the reduction rate of carbon consumption intensity is 7% or more.
  • the blowing temperature of the high-concentration hydrogen-containing gas becomes more than 600 ° C and 900 ° C or lower, the reduction rate of the carbon consumption intensity as the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas increases.
  • the upper limit of the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is not particularly set.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas reaches about 1000 Nm 3 / t, the effect of reducing the carbon consumption intensity is expected to peak, so hydrogen in the high-concentration hydrogen-containing gas
  • the amount of gas blown may be 1000 Nm 3 / t or less.
  • the upper limit of the blowing temperature is not particularly limited as long as the blowing temperature of the high-concentration hydrogen-containing gas can exceed 600 ° C.
  • the effect of reducing the carbon consumption intensity is almost flat in the range where the blowing temperature of the high-concentration hydrogen-containing gas is in the range of more than 1200 ° C to about 1400 ° C.
  • FIG. 15 and FIG. 16 show the correlation between the blowing temperature of pure hydrogen gas and the blowing amount of pure hydrogen gas required to set the carbon consumption intensity reduction rate Input ⁇ C to 10% or 20%. It is a graph which shows. The tuyere front temperature Tf was 2100 ° C. These graphs show the correlation between FIGS.
  • the blowing temperature of the high-concentration hydrogen-containing gas may be 1400 ° C. or lower. That is, the blowing temperature of the high-concentration hydrogen-containing gas may be, for example, more than 600 ° C. and 1400 ° C. or lower.
  • the tuyere for blowing the high-concentration hydrogen-containing gas is, for example, a tuyere for blowing hot air provided in the lower part of the furnace.
  • the description will be made on the premise that the high-concentration hydrogen-containing gas is blown from the tuyere for blowing hot air, but the tuyere for blowing the high-concentration hydrogen-containing gas is not limited to this.
  • the tuyere is a so-called shaft tuyere provided on the shaft portion.
  • the high-concentration hydrogen-containing gas may be blown into the blast furnace from any of these tuyere, or may be blown into the blast furnace from both tuyere.
  • the total amount of hydrogen gas blown into the high-concentration hydrogen-containing gas blown from each tuyere matches the above-determined blowing amount.
  • the tuyere front temperature Tf is maintained at 2050 ° C. or lower.
  • the tuyere front temperature Tf is the furnace temperature at the tip of the tuyere inside the furnace, and is also referred to as the tuyere tip temperature Tf.
  • the tuyere temperature Tf is calculated as the tuyere tip theoretical combustion temperature according to the Lamb's formula described in the "Pig Iron Handbook" (Chijin Shokan) by Akitoshi Shigemi.
  • the tuyere temperature Tf is 2050 ° C. or lower (2000 ° C. in FIGS. 2, 3, 5, 7, and 9).
  • the reduction rate of carbon consumption intensity in the case of Input ⁇ C is 2100 ° C. and 2200 ° C. in FIGS. 2, FIG. 3, FIG. 5, FIG. 7, and FIG. 9 when the tuyere temperature Tf exceeds 2050 ° C. )
  • Reduction rate of carbon consumption intensity is larger than Input ⁇ C. Therefore, in the first modification, the tuyere front temperature Tf is maintained at 2050 ° C. or lower. As a result, the reduction rate Input ⁇ C of the carbon consumption intensity can be further increased. As shown in FIGS.
  • the tuyere temperature Tf is lowered by blowing the high-concentration hydrogen-containing gas into the blast furnace.
  • the hot air blown into the blast furnace is a gas containing air.
  • the hot air may further contain moisture and enriched oxygen in addition to air.
  • the tuyere temperature Tf is preferably 2000 ° C. or higher. However, if the reduction rate Input ⁇ C of the carbon consumption intensity is sufficiently large and the pulverized coal ratio (the pulverized coal used per ton of hot metal) can be sufficiently lowered, the tuyere temperature Tf is less than 2000 ° C. There may be. For example, even if the tuyere temperature Tf is less than 2000 ° C., the tuyere temperature Tf may be less than 2000 ° C. as long as the reduction rate Input ⁇ C of the carbon consumption intensity can be maintained and stable operation is possible.
  • the blowing temperature of the high-concentration hydrogen-containing gas is 1200 ° C. and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 800 Nm 3 / t or more, pulverized coal.
  • the blowing amount is 0 (that is, the pulverized coal ratio is 0).
  • the reduction rate Input ⁇ C of the carbon consumption intensity can be maintained even if the tuyere temperature Tf is less than 2000 ° C., and stable operation becomes possible. Therefore, the tuyere front temperature Tf can be set to less than 2000 ° C.
  • the tuyere front temperature Tf may be set to less than 2000 ° C.
  • the tuyere front temperature Tf is maintained above 2050 ° C. and below 2150 ° C.
  • the reduction rate Input ⁇ C of the carbon consumption intensity can be increased by setting the tuyere front temperature Tf to 2050 ° C. or lower.
  • the combustion rate of pulverized coal may decrease. That is, when the tuyere temperature Tf decreases, it becomes difficult for the pulverized coal to burn.
  • the pulverized coal is flame-retardant or when the operation is performed with a high pulverized coal ratio, the possibility that the combustion rate of the pulverized coal decreases is further increased.
  • the temperature inside the furnace decreases, so that it may be necessary to carry out an operation in which the ratio of the reducing agent is increased accordingly.
  • the tuyere front temperature Tf is maintained above 2050 ° C and below 2150 ° C. As a result, the combustion rate of the pulverized coal can be maintained, and thus the decrease in the temperature inside the furnace can be suppressed.
  • the tuyere front temperature Tf is maintained above 2150 ° C.
  • the tuyere temperature Tf is often set to about 2200 ° C. Therefore, by setting the tuyere front temperature Tf to more than 2150 ° C., the operation can be performed without significantly changing the operating conditions from the conventional blast furnace operation.
  • the tuyere front temperature Tf is preferably 2250 ° C. or lower.
  • the reduction ratio of carbon consumption intensity to each of several blown amounts is calculated by the blast furnace operation simulation that reflects the current blast furnace operation including the blowing temperature of the high-concentration hydrogen-containing gas.
  • the specific method may be the same as that of the examples described later.
  • the horizontal axis is the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas in the unit Nm 3 / t
  • the vertical axis is the reduction rate of carbon consumption intensity Input ⁇ C (%). Plot the calculated value.
  • the approximate curves of these plots may be obtained by, for example, the least squares method, and the relational expression showing the approximate curves, more specifically, the approximate curves may be used as the above-mentioned injection amount-carbon consumption intensity reduction ratio correlation. ..
  • the correlation between the amount of blown material and the reduction rate of carbon consumption intensity is preferably obtained for each tuyere temperature Tf.
  • the reduction rate of carbon consumption intensity is larger than that of the current operation.
  • Input ⁇ C is larger. That is, the injection amount for which carbon consumption is reduced is calculated above. Determined based on correlation. Then, a high-concentration hydrogen-containing gas is blown from the tuyere at the determined blowing amount. As a result, the reduction rate Input ⁇ C of the carbon consumption intensity can be increased more reliably.
  • FIG. 12 shows the correlation between the amount of pure hydrogen gas blown at room temperature in the unit Nm 3 / t and the amount of change in pressure loss in the unit kPa with respect to the base operation, which is an operation in which high-concentration hydrogen-containing gas is not blown. It is a graph which shows for each pre-temperature Tf. This graph is obtained by blast furnace operation simulation. Details will be described in Examples.
  • the pressure loss is the difference between the pressure at the tuyere tip (in front of the tuyere), in other words, the pressure inside the furnace at the outlet of the tuyere and the pressure at the top of the furnace, excluding the pipe pressure loss from the blower to the tuyere tip. Value.
  • the pressure loss is measured by a pressure gauge installed on the furnace wall.
  • the amount of change in pressure loss with respect to the base operation is the value obtained by subtracting the pressure loss during the base operation from the pressure loss during a certain operation. It is preferable that the pressure loss is about the same as that of the base operation or lower than that of the base operation from the viewpoint of restricting the blowing pressure and preventing blow-by.
  • FIG. 12 shows the above correlation when pure hydrogen gas at room temperature is used, but the above correlation can also be obtained when a high-concentration hydrogen-containing gas other than pure hydrogen gas is used. Further, the above correlation can be obtained even if the blowing temperature of the high-concentration hydrogen-containing gas is higher than room temperature.
  • the oxygen enrichment rate is adjusted while keeping the amount of tapping at a predetermined amount. Therefore, as the oxygen enrichment rate increases, the flow rate of hot air decreases. As a result, the amount of Bosch gas is reduced. In other words, when the tuyere temperature Tf is low, the amount of Bosch gas increases. As a result, the pressure loss may be larger than that of the base operation.
  • the injection amount-carbon consumption intensity reduction ratio correlation is obtained in advance in the same manner as in the modified example 4. Furthermore, the correlation between the amount of blown air and the amount of change in pressure loss, which is the correlation between the amount of blown air and the amount of change in pressure loss with respect to the base operation, is obtained.
  • the amount of change in pressure loss with respect to each of several blowing amounts is obtained by a blast furnace operation simulation that reflects the current blast furnace operation including the blowing temperature of high-concentration hydrogen-containing gas.
  • the specific method may be the same as that of the examples described later.
  • the above method is on a plane in which the horizontal axis is the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas in the unit Nm 3 / t and the vertical axis is the amount of change in the pressure loss in the unit kPa. Plot the value obtained in.
  • the approximate curves of these plots may be obtained by, for example, the least squares method, and this approximate curve (more specifically, the relational expression showing the approximate curve) may be used as the above-mentioned blow amount-pressure loss change amount correlation.
  • the correlation between the amount of blown air and the amount of change in pressure loss is preferably obtained for each tuyere temperature Tf.
  • the reduction rate Input ⁇ C of the carbon consumption intensity is larger than that of the current operation, that is, the amount of injection is injected so that the amount of carbon consumption is reduced and the amount of change in pressure loss is within a predetermined range.
  • the predetermined range is, for example, about ⁇ 50 to +5 kPa, but is not limited to this.
  • a high-concentration hydrogen-containing gas is blown from the tuyere at the determined blowing amount. As a result, it is possible to more reliably increase the reduction rate Input ⁇ C of the carbon consumption intensity while keeping the amount of change in pressure loss within a predetermined range.
  • FIG. 13 is a graph showing the correlation between the amount of pure hydrogen gas blown in the unit Nm 3 / t at room temperature and the amount of change in the furnace top gas temperature with respect to the base operation at the unit ° C. for each tuyere temperature Tf. .. This graph is obtained by blast furnace operation simulation. Details will be described in Examples.
  • the furnace top gas temperature is the temperature of the top gas (mainly CO 2 , N 2 , unreacted CO, etc.) discharged from the top of the blast furnace, and is installed in the riser pipe or the like in actual operation. Measured by a thermometer.
  • the amount of change in the top gas temperature with respect to the base operation is a value obtained by subtracting the top gas temperature during the base operation from the top gas temperature during a certain operation.
  • the furnace top gas temperature is preferably about the same as the base operation from the viewpoint of restrictions on the furnace top equipment and operational efficiency, and as an example, the furnace top gas temperature of the base operation is preferably within the range of about ⁇ 20 ° C. ..
  • FIG. 13 shows the above correlation when a pure hydrogen gas at room temperature is used, but the above correlation can also be obtained when a high-concentration hydrogen-containing gas other than the pure hydrogen gas is used. Further, the above correlation can be obtained even if the blowing temperature of the high-concentration hydrogen-containing gas is higher than room temperature.
  • the amount of Bosch gas is reduced.
  • the heat flow ratio expressed by (heat capacity of the furnace interior container falling per unit time) / (heat capacity of Bosch gas rising per unit time) increases.
  • the temperature of the gas in the furnace that rises in the furnace tends to decrease, and as a result, the temperature of the gas at the top of the furnace tends to decrease.
  • the temperature of the furnace top gas may be lower than that of the base operation.
  • the operation is performed by increasing the reducing agent ratio.
  • the reducing agent ratio is increased, the amount of heat input into the furnace increases and the furnace top gas temperature tends to rise. The furnace top gas temperature starts to increase.
  • the injection amount-carbon consumption intensity reduction ratio correlation is obtained in advance in the same manner as in the modified example 4. Furthermore, the correlation between the blown amount and the change in the top gas temperature with respect to the base operation, which is the correlation between the blown amount and the change in the top gas temperature, is obtained.
  • the amount of change in the furnace top gas temperature for each of several injection amounts is obtained by a blast furnace operation simulation that reflects the current blast furnace operation including the injection temperature of high-concentration hydrogen-containing gas.
  • the specific method may be the same as that of the examples described later.
  • the horizontal axis is the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas in the unit Nm 3 / t
  • the vertical axis is the amount of change in the furnace top gas temperature in the unit ° C.
  • the values obtained by the above method are plotted above.
  • the approximate curves of these plots may be obtained by, for example, the least squares method, and the relational expression showing the approximate curves, more specifically, the approximate curves may be used as the above-mentioned injection amount-furnace top gas temperature change amount correlation. ..
  • the correlation between the amount of blown gas and the amount of change in the temperature of the top gas is preferably obtained for each tuyere front temperature Tf.
  • the reduction rate Input ⁇ C of the carbon consumption intensity is larger than that of the current operation, that is, the amount of injection is such that the carbon consumption is reduced and the amount of change in the furnace top gas temperature is within the predetermined range.
  • the predetermined range is, for example, about ⁇ 20 to + 20 ° C., but is not limited thereto.
  • the parameter paired with the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is not necessarily limited to the reduction rate Input ⁇ C of the carbon consumption intensity. That is, the parameter paired with the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas may be any parameter related to carbon consumption, that is, any carbon consumption parameter. This is because if carbon consumption is reduced, CO 2 emissions can be reduced. Examples of such a carbon consumption parameter include a reduction rate of carbon consumption intensity, Input ⁇ C, a carbon consumption intensity, a reducing agent ratio, a reduction rate of the reducing agent ratio, and the like.
  • the reduction ratio of the reducing agent ratio is the reduction ratio of the reducing agent ratio with respect to the base operation, and the method of obtaining it is the same as the method of obtaining the reduction ratio Input ⁇ C of the carbon consumption intensity.
  • the modification 5 and the modification 6 may be combined. As a result, while keeping the amount of change in pressure loss and the amount of change in furnace top gas temperature within a predetermined range, the reduction rate Input ⁇ C of the carbon consumption intensity can be increased more reliably.
  • Example 1 Verification when the blowing temperature of the high-concentration hydrogen-containing gas is room temperature to 600 ° C> As described above, the correlation between the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas and the reduction rate of carbon consumption intensity Input ⁇ C shows different behavior with the blowing temperature of 600 ° C. as a boundary. Therefore, in Example 1, verification was performed when the blowing temperature of the high-concentration hydrogen-containing gas was 600 ° C. or lower.
  • blast furnace mathematical model For blast furnace operation simulation, Koji TAKATANI, Takanobu INADA, Yutaka UJISAWA, "Three-dimensional Dynamic Simulation for Blast Furnace", ISIJ International, Vol. 39 (1999), No. 1, p.
  • the so-called "blast furnace mathematical model” shown in 15-22 and the like was used. This blast furnace mathematical model roughly defines a plurality of meshes (small regions) by dividing the internal region of the blast furnace into the height direction, the radial direction, and the circumferential direction, and simulates the behavior of each mesh. is there.
  • the amount of high-concentration hydrogen-containing gas blown is set as the amount of high-concentration hydrogen-containing gas blown from the tuyere.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is set as the amount obtained by multiplying the amount of high-concentration hydrogen-containing gas blown by the ratio of hydrogen gas in the unit mol%.
  • the blowing temperature of the high-concentration hydrogen-containing gas is set as the temperature of the high-concentration hydrogen-containing gas when the high-concentration hydrogen-containing gas is blown from the tuyere.
  • the tuyere temperature Tf is calculated as a result of considering the combustion heat of various gases, the sensible heat of the blast, the temperature of coke flowing into the tuyere tip (in front of the tuyere), various reaction heats, and the like.
  • the pressure loss is calculated by using the ergun equation as the pressure loss of the filling layer in the furnace.
  • the furnace top gas temperature is calculated as the gas temperature in the outermost layer (uppermost layer) of the furnace interior container.
  • the calculation conditions are shown in Table 1.
  • the coke ratio in Table 1 is the amount of coke used per ton of hot metal.
  • Table 2 shows the specifications of the base operation in which a high-concentration hydrogen-containing gas is not blown.
  • the tuyere temperature Tf was set to any of 2000 ° C., 2100 ° C., and 2200 ° C.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas was set to 0 to 600 Nm 3 / t.
  • the amount of air blown, the oxygen enrichment rate, and the amount of PC (pulverized coal) blown were adjusted so that the hot metal output ratio and the hot metal temperature were constant in all operations.
  • Example 1-1 A case where the blowing temperature of the high-concentration hydrogen-containing gas is room temperature to 600 ° C. and the high-concentration hydrogen-containing gas is pure hydrogen gas>
  • the high-concentration hydrogen-containing gas is regarded as pure hydrogen gas, and the amount of pure hydrogen gas blown and the reduction ratio of the carbon consumption intensity are reduced.
  • the correlation with Input ⁇ C was calculated. The results are shown in FIGS. 2 to 5.
  • the reduction rate of carbon consumption intensity Input ⁇ C does not simply increase as the blowing amount increases. It was found that when the amount of blown air increased to some extent, it became saturated and started to decrease. Then, it was found that the amount of blown air when the reduction rate of carbon consumption intensity, Input ⁇ C, was saturated and started to decrease was slightly different depending on the blown temperature. That is, it was found that there is an appropriate range of the blowing amount for each blowing temperature.
  • the appropriate range is 200 to 500 Nm 3 / t when the blowing temperature is room temperature to 300 ° C, and 145 Nm 3 / t or more when the blowing temperature is more than 300 ° C and 600 ° C or less. It became. Further, as shown in FIGS. 4 and 5, the reduction rate Input ⁇ C of the carbon consumption intensity does not simply increase with the increase in the blowing amount, and when the blowing temperature is 600 ° C., the blowing is performed. It was found that the amount was saturated at about 600 Nm 3 / t, and when the blowing temperature was 350 ° C., the blowing amount peaked at about 300 Nm 3 / t and started to decrease as the blowing amount increased.
  • the reduction rate of carbon consumption intensity is 7% or more when the blowing amount is within the appropriate range of 145 Nm 3 / t or more. It became possible to. Further, as shown in FIGS. 2 to 5, the reduction ratio Input ⁇ C of the carbon consumption intensity with respect to the same blowing amount differs depending on the tuyere temperature Tf, and when the tuyere temperature Tf becomes 2000 ° C. It was also found to be the largest. The reason why such a phenomenon is obtained is as described above.
  • the reduction rate of carbon consumption intensity Input ⁇ C can be increased, and CO 2 emissions can be significantly reduced. can do.
  • Example 1-2 In Example 1-2, it was confirmed that even if the high-concentration hydrogen-containing gas contained a gas other than hydrogen gas, the same operation as in the case of pure hydrogen gas was possible. Specifically, assuming a 80mol% H 2 -20mol% N 2 gas composed of 80 mol% of hydrogen gas and 20 mol% of nitrogen gas as a high-concentration hydrogen-containing gas. Then, the blast furnace operation simulation was performed in the same manner as in Example 1 with the blowing temperature being 25 ° C. and the tuyere front temperature Tf being 2100 ° C. The results are shown in FIG.
  • Figure 11 shows by comparing the calculation result of the calculation results of pure hydrogen gas (100 mol% H 2 gas) and 80mol% H 2 -20mol% N 2 gas.
  • the horizontal axis of FIG. 11, the flow rate of the mixed gas is obtained by converting the pure hydrogen gas, i.e., a value obtained by multiplying the 80 mol% to the flow rate of 80mol% H 2 -20mol% N 2 gas.
  • the proper scope of the blowing amount in terms of pure hydrogen gas is maintained at the case of pure hydrogen gas, it is slightly lowered only effect allowance I understood it.
  • Example 1-3> In Example 1-3, pure hydrogen gas at room temperature was used as the high-concentration hydrogen-containing gas, and the amount of change in pressure loss with respect to each of several blowing amounts (the amount of change in pressure loss with respect to the base operation) was determined. .. The result is shown in FIG. As is clear from FIG. 12, it was found that there is a certain correlation between the amount of pure hydrogen gas blown and the amount of change in pressure loss. For example, it was found that when the tuyere temperature Tf is low, the pressure loss may be large with respect to the base operation. However, the pressure loss decreased as the amount of pure hydrogen gas blown increased. More specifically, when the tuyere temperature Tf was 2000 ° C.
  • the blowing amount-pressure loss change amount correlation which is the correlation between the blowing amount of hydrogen gas in the high concentration hydrogen-containing gas and the change amount of the pressure loss with respect to the base operation, is obtained.
  • Blow of hydrogen gas in high-concentration hydrogen-containing gas which is obtained in advance for each tuyere temperature Tf, carbon consumption is reduced compared to the current operation, and the amount of change in pressure loss is within a predetermined range.
  • the reduction rate of carbon consumption intensity Imput ⁇ C is set while keeping the amount of change in pressure loss within a predetermined range. It turns out that it can be made larger.
  • the blowing amount was 250 to 300 Nm 3 / t
  • the amount of change in the furnace top gas temperature was a value outside the above-mentioned predetermined range.
  • the blowing amount may be adjusted in consideration of the correlation between the blowing amount of pure hydrogen gas and the change amount of the furnace top gas temperature.
  • the blowing amount-the top gas temperature which is the correlation between the blowing amount of hydrogen gas in the high-concentration hydrogen-containing gas and the change in the furnace top gas temperature with respect to the base operation.
  • the change amount correlation is obtained in advance for each tuyere temperature, and in high-concentration hydrogen-containing gas where the carbon consumption is reduced compared to the current operation and the change amount of the furnace top gas temperature is within a predetermined range. It was found that the decrease in operational efficiency can be suppressed by determining the amount of hydrogen gas blown in based on the amount of blown hydrogen-carbon consumption parameter correlation and the amount of blown hydrogen-relationship of the temperature change of the furnace top gas. It was.
  • Example 2 Verification when the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C> In Example 2, the case where the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C. was verified.
  • Example 2 The same blast furnace mathematical model as in Example 1 was used for the blast furnace operation simulation.
  • the calculation conditions are shown in Table 3.
  • Table 3 the calculation conditions were almost the same as those in Example 1, but the coke ratio was different from that in Example 1. That is, in Example 2, the coke ratio is constant at 300 kg / t when the pulverized coal injection amount is larger than 0 ton / h, and the pulverized coal injection amount is 0 ton / h (that is, the pulverized coal ratio is 0 ton / h). When it becomes 0), it is decided to change. That is, when the amount of pulverized coal blown was 0 ton / h, the furnace temperature was adjusted by the coke ratio.
  • the pulverized coal blowing amount can be 0 ton / h. In this case, by reducing the coke ratio, it is possible to further reduce the carbon consumption intensity.
  • the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas was set to 0 to 1000 Nm 3 / t. Further, the blowing temperature of the high-concentration hydrogen-containing gas was set to more than 600 ° C and 1400 ° C or less.
  • the specifications of the base operation in which the high-concentration hydrogen-containing gas was not blown were the same as in Example 1. Other conditions were the same as in Example 1.
  • the amount of air blown, the oxygen enrichment rate, and the amount of PC (pulverized coal) blown were adjusted so that the hot metal output ratio and the hot metal temperature were constant in all operations.
  • the iron-based raw material was the sinter used in Example 1.
  • Example 2-1 Case where the blowing temperature of the high-concentration hydrogen-containing gas is over 600 ° C. and the high-concentration hydrogen-containing gas is pure hydrogen gas>
  • Example 2-1 using a high-concentration hydrogen-containing gas as pure hydrogen gas the correlation between the amount of pure hydrogen gas blown and the reduction rate Input ⁇ C of the carbon consumption intensity was calculated. The results are shown in FIGS. 6 to 10.
  • the range in which the reduction rate Input ⁇ C of the carbon consumption intensity was 7% or more was different depending on the blowing temperature of the high-concentration hydrogen-containing gas. Specifically, when the blowing temperature is more than 600 ° C. and 900 ° C. or lower, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is within the range of 125 Nm 3 / t or more. The reduction rate of carbon consumption intensity Input ⁇ C was 7% or more. Further, when the blowing temperature is more than 900 ° C. and 1200 ° C. or lower, the carbon consumption source is when the blowing amount of hydrogen gas in the high-concentration hydrogen-containing gas is within the range of 110 Nm 3 / t or more.
  • the unit reduction rate, Input ⁇ C was 7% or more.
  • the blowing temperature exceeds 1200 ° C, when the blowing amount of hydrogen gas in the high-concentration hydrogen-containing gas is within the range of 100 Nm 3 / t or more, the reduction rate of carbon consumption intensity Input ⁇ C was 7% or more.
  • the amount of change in the furnace top gas temperature is set to a value within a predetermined range, and the reduction rate of carbon consumption intensity is Imput ⁇ . C can be increased.

Abstract

According to one aspect of the present invention, provided is a blast furnace operation method characterized in that a high-concentration hydrogen-containing gas which contains at least 80 mol% of hydrogen gas, is blown from a tuyere under certain conditions such as: a condition in which the blowing temperature of the high-concentration hydrogen-containing gas is room temperature to 300 °C, and the blown amount of hydrogen gas in the high-concentration hydrogen-containing gas is 200 Nm3/t to 500 Nm3/t; a condition in which the blowing temperature of the high-concentration hydrogen-containing gas is 300 °C to 600 °C, and the blown amount of hydrogen gas in the high-concentration hydrogen-containing gas is at least 145 Nm3/t; or a condition in which the blowing temperature of the high-concentration hydrogen-containing gas is 600 °C to 900 °C, and the blown amount of the high-concentration hydrogen-containing gas is at least 125 Nm3/t.

Description

高炉の操業方法How to operate the blast furnace
　本発明は、高炉の操業方法に関する。
　本願は、２０１９年１１月２９日に日本に出願された特願２０１９－２１６５６８号及び２０２０年５月２７日に日本に出願された特願２０２０－０９２４６７号に基づき優先権を主張し、それらの内容をここに援用する。 The present invention relates to a method of operating a blast furnace.
The present application claims priority based on Japanese Patent Application No. 2019-216568 filed in Japan on November 29, 2019 and Japanese Patent Application No. 2020-92467 filed in Japan on May 27, 2020. The contents are used here.
　鉄鋼業においては、高炉法が銑鉄製造工程の主流を担っている。高炉法においては、高炉の炉頂から高炉用鉄系原料（酸化鉄を含む原料。主として、焼結鉱。以下、単に「鉄系原料」とも称する）及びコークスを高炉内に交互かつ層状に装入する一方で、高炉下部の羽口から熱風を高炉内に吹き込む。熱風は、熱風とともに吹き込まれる微粉炭、及び、高炉内のコークスと反応することで、高温の還元ガス（ここでは主としてＣＯガス）を発生させる。すなわち、熱風は、コークス及び微粉炭をガス化させる。還元ガスは、高炉内を上昇し、鉄系原料を加熱しながら還元する。鉄系原料は、高炉内を降下する一方で、還元ガスにより加熱及び還元される。その後、鉄系原料は溶融し、コークスによってさらに還元されながら高炉内を滴下する。鉄系原料は、最終的には炭素を５質量％弱含む溶銑（銑鉄）として炉床部に溜められる。炉床部の溶銑は、出銑口から取り出され、次の製鋼プロセスに供される。したがって、高炉法では、コークス及び微粉炭等の炭材を還元材として使用する。 In the steel industry, the blast furnace method is the mainstream of the pig iron manufacturing process. In the blast furnace method, iron-based raw materials for blast furnaces (raw materials containing iron oxide, mainly sintered ore, hereinafter simply referred to as "iron-based raw materials") and coke are alternately and layered in the blast furnace from the top of the blast furnace. While entering, hot air is blown into the blast furnace from the tuyere at the bottom of the blast furnace. The hot air reacts with the pulverized coal blown together with the hot air and the coke in the blast furnace to generate a high-temperature reducing gas (mainly CO gas in this case). That is, the hot air gasifies coke and pulverized coal. The reducing gas rises in the blast furnace and reduces the iron-based raw material while heating it. The iron-based raw material is heated and reduced by the reducing gas while descending in the blast furnace. After that, the iron-based raw material is melted and dropped in the blast furnace while being further reduced by coke. The iron-based raw material is finally stored in the hearth as hot metal (pig iron) containing a little less than 5% by mass of carbon. The hot metal in the hearth is taken out from the hot metal outlet and used for the next steelmaking process. Therefore, in the blast furnace method, a charcoal material such as coke and pulverized coal is used as a reducing material.
　ところで、近年、地球温暖化防止が叫ばれ、温室効果ガスの一つである二酸化炭素（ＣＯ２ガス）の排出量削減が社会問題になっている。上述したように、高炉法では、還元材として炭材を使用するので、大量のＣＯ２ガスを発生する。したがって、鉄鋼業はＣＯ２ガス排出量において主要な産業のひとつとなっており、その社会的要請に応えねばならない。具体的には、高炉操業での更なる還元材比（溶銑１トンあたりの還元材使用量）の削減が急務となっている。 By the way, in recent years, prevention of global warming has been called for, and reduction of carbon dioxide (CO 2 gas) emission, which is one of greenhouse gases, has become a social problem. As described above, in the blast furnace method, since a charcoal material is used as a reducing material, a large amount of CO 2 gas is generated. Therefore, the steel industry has become one of the major industries in terms of CO 2 gas emissions and must meet its social demands. Specifically, there is an urgent need to further reduce the ratio of reducing agents (the amount of reducing agents used per ton of hot metal) in blast furnace operation.
　還元材は炉内で熱となって装入物を昇温させる役割と、炉内の鉄系原料を還元する役割があり、還元材比を低減させるためには炉内の還元効率を上げる必要がある。炉内の還元反応は様々な反応式で表記することができる。これらの還元反応のうち、コークスによる直接還元反応（反応式：ＦｅＯ＋Ｃ⇒Ｆｅ＋ＣＯ）は大きな吸熱を伴う吸熱反応である。したがって、この反応を極力発生させないことが還元材比の低減において重要となる。この直接還元反応は高炉炉下部で生じる反応であるため、鉄系原料が炉下部に至るまでにＣＯ、Ｈ２等の還元ガスで鉄系原料を十分に還元することができれば、直接還元反応の対象となる鉄系原料を減らすことができる。 The reducing agent has the role of raising the temperature of the charged material as heat in the furnace and the role of reducing the iron-based raw material in the furnace. In order to reduce the ratio of the reducing agent, it is necessary to increase the reduction efficiency in the furnace. There is. The reduction reaction in the furnace can be expressed by various reaction formulas. Among these reduction reactions, the direct reduction reaction by coke (reaction formula: FeO + C⇒Fe + CO) is an endothermic reaction accompanied by a large endothermic reaction. Therefore, it is important to prevent this reaction from occurring as much as possible in order to reduce the ratio of reducing agents. Since this direct reduction reaction occurs in the lower part of the blast furnace, if the iron-based raw material can be sufficiently reduced with a reducing gas such as CO and H 2 by the time the iron-based raw material reaches the lower part of the furnace, the direct reduction reaction will occur. The target iron-based raw materials can be reduced.
　上記課題を解決するための従来技術として、例えば特許文献１～６に開示されるように、羽口から熱風と共に還元ガス（Ｈ２ガス、ＣＯＧ（Ｃｏｋｅｓ　Ｏｖｅｎ　Ｇａｓ）、天然ガス、都市ガス等）を吹き込むことで、炉内の還元ガスポテンシャルを向上させる技術が知られている。還元ガスが炭素含有還元ガス（ガスの分子構造に炭素原子が含まれる還元ガス。例えば炭化水素ガス）となる場合、炭素含有ガス中の炭素原子が高炉内でＣＯガスとなり、鉄系原料を還元する。還元ガスが水素ガス（Ｈ２ガス）となる場合、水素ガスが鉄系原料を還元する。これにより、直接還元反応の対象となる鉄系原料を減らすことができる。なお、以下の説明では、特に断りがない限り、「炭素」、「水素」はそれぞれ、炭素原子、水素原子を意味するものとする。 As a conventional technique for solving the above problems, as disclosed in Patent Documents 1-6, a reducing gas with the hot air from tuyere (H 2 gas, COG (Cokes Oven Gas), natural gas, city gas, etc.) There is known a technique for improving the reducing gas potential in the furnace by injecting. When the reducing gas becomes a carbon-containing reducing gas (a reducing gas containing carbon atoms in the molecular structure of the gas, for example, a hydrocarbon gas), the carbon atoms in the carbon-containing gas become CO gas in the blast furnace, and the iron-based raw material is reduced. To do. When the reducing gas becomes hydrogen gas (H 2 gas), the hydrogen gas reduces the iron-based raw material. As a result, the number of iron-based raw materials subject to the direct reduction reaction can be reduced. In the following description, unless otherwise specified, "carbon" and "hydrogen" mean carbon atoms and hydrogen atoms, respectively.
日本国特許第６０１９８９３号公報Japanese Patent No. 60198993 日本国特許第５９８７７７３号公報Japanese Patent No. 5987773 日本国特許第５０５０７０６号公報Japanese Patent No. 5050706 日本国特許第５７７０１２４号公報Japanese Patent No. 5770124 日本国特許第５３１５７３２号公報Japanese Patent No. 5315732 日本国特許第５８５１８２８号公報Japanese Patent No. 5851828
　しかし、特許文献１～６に開示された技術では、羽口から吹き込まれる還元ガスの吹込み量が少なく、ＣＯ２排出量の削減効果が小さかった。 However, in the techniques disclosed in Patent Documents 1 to 6, the amount of reducing gas blown from the tuyere is small, and the effect of reducing CO 2 emissions is small.
　そこで、本発明は、上記問題に鑑みてなされたものであり、本発明の目的とするところは、高炉操業を安定に維持しつつ羽口から吹き込まれる還元ガスとしての高濃度水素含有ガスの吹込み量を増加し、ＣＯ２排出量をさらに削減することが可能な、新規かつ改良された高炉の操業方法を提供することにある。 Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to blow a high-concentration hydrogen-containing gas as a reduction gas blown from a tuyere while maintaining stable blast furnace operation. It is an object of the present invention to provide a new and improved method of operating a blast furnace capable of increasing the filling amount and further reducing the CO 2 emission.
　上記課題を解決するために、本発明のある観点によれば、水素ガスを８０ｍｏｌ％以上含有する高濃度水素含有ガスを、高濃度水素含有ガスの吹込み温度が常温以上３００℃以下であり、かつ、高濃度水素含有ガス中の水素ガスの吹込み量が２００Ｎｍ３／ｔ以上５００Ｎｍ３／ｔ以下である条件、高濃度水素含有ガスの吹込み温度が３００℃超６００℃以下であり、かつ、高濃度水素含有ガス中の水素ガスの吹込み量が１４５Ｎｍ３／ｔ以上である条件、高濃度水素含有ガスの吹込み温度が６００℃超９００℃以下であり、かつ、高濃度水素含有ガスの吹込み量が１２５Ｎｍ３／ｔ以上である条件、高濃度水素含有ガスの吹込み温度が９００℃超１２００℃以下であり、かつ、高濃度水素含有ガス中の水素ガスの吹込み量が１１０Ｎｍ３／ｔ以上である条件、または、高濃度水素含有ガスの吹込み温度が１２００℃超であり、かつ、高濃度水素含有ガス中の水素ガスの吹込み量が１００Ｎｍ３／ｔ以上である条件で、羽口から吹き込むことを特徴とする、高炉の操業方法が提供される。 In order to solve the above problems, according to a certain viewpoint of the present invention, a high-concentration hydrogen-containing gas containing 80 mol% or more of hydrogen gas is blown into a high-concentration hydrogen-containing gas at a temperature of room temperature or higher and 300 ° C. or lower. and conditions blowing amount of the hydrogen gas in the high concentration hydrogen-containing gas is less than 200 Nm 3 / t or more 500 Nm 3 / t, and the blowing temperature of the high concentration hydrogen-containing gas is 300 ° C. ultra 600 ° C. or less, and The condition that the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 145 Nm 3 / t or more, the blow-in temperature of the high-concentration hydrogen-containing gas is more than 600 ° C. and 900 ° C. or less, and the high-concentration hydrogen-containing gas The amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 110 Nm under the condition that the amount of hydrogen gas blown is 125 Nm 3 / t or more, the temperature of the high-concentration hydrogen-containing gas is more than 900 ° C. and 1200 ° C. or less. A condition of 3 / t or more, or a condition that the blowing temperature of the high-concentration hydrogen-containing gas is over 1200 ° C. and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 100 Nm 3 / t or more. Then, a method of operating a blast furnace, which is characterized by blowing from a tuyere, is provided.
　ここで、高濃度水素含有ガスの吹込み温度が常温以上３００℃以下であり、かつ、高濃度水素含有ガス中の水素ガスの吹込み量が２００Ｎｍ３／ｔ以上３００Ｎｍ３／ｔ以下であってもよい。 Here, the blowing temperature of the high-concentration hydrogen-containing gas is room temperature or higher and 300 ° C. or lower, and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 200 Nm 3 / t or higher and 300 Nm 3 / t or lower. May be good.
　また、高濃度水素含有ガスの吹込み温度が３００℃超６００℃以下であり、かつ、高濃度水素含有ガス中の水素ガスの吹込み量が１４５Ｎｍ３／ｔ以上６００Ｎｍ３／ｔ以下であってもよい。 Further, the blowing temperature of the high-concentration hydrogen-containing gas is more than 300 ° C. and 600 ° C. or less, and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 145 Nm 3 / t or more and 600 Nm 3 / t or less. May be good.
　また、羽口前温度を２０５０℃以下としてもよい。 Further, the temperature in front of the tuyere may be 2050 ° C. or lower.
　また、羽口前温度を２０５０℃超２１５０℃以下としてもよい。 Further, the temperature in front of the tuyere may be more than 2050 ° C and 2150 ° C or less.
　また、羽口前温度を２１５０℃超２２５０℃以下としてもよい。 Further, the temperature in front of the tuyere may be more than 2150 ° C and 2250 ° C or less.
　また、高濃度水素含有ガスの吹込み温度が６００℃超１４００℃以下であってもよい。 Further, the blowing temperature of the high-concentration hydrogen-containing gas may be more than 600 ° C and 1400 ° C or less.
　また、高濃度水素含有ガスの吹込み温度が６００℃超となる場合、高濃度水素含有ガス中の水素ガスの吹込み量を１０００Ｎｍ３／ｔ以下としてもよい。 When the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C., the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas may be 1000 Nm 3 / t or less.
　また、高濃度水素含有ガスの吹込み温度が６００℃超であり、かつ、高濃度水素含有ガス中の水素ガスの吹込み量が４００Ｎｍ３／ｔ以上となる場合、羽口前温度を２０５０℃以下としてもよい。 Further, when the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C. and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 400 Nm 3 / t or more, the temperature before the tuyere is set to 2050 ° C. It may be as follows.
　本発明の他の観点によれば、水素ガスを８０ｍｏｌ％以上含有する高濃度水素含有ガスの吹込み温度が所定値であるときの、高濃度水素含有ガス中の水素ガスの吹込み量と炭素消費量に関する炭素消費パラメータとの相関である吹込み量－炭素消費パラメータ相関を羽口前温度毎に予め求めておき、現状の操業よりも炭素消費量が低減する高濃度水素含有ガス中の水素ガスの吹込み量を当該吹込み量－炭素消費パラメータ相関に基づいて決定し、高濃度水素含有ガスを当該決定された吹込み量で羽口から吹き込むことを特徴とする、高炉の操業方法が提供される。 According to another aspect of the present invention, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas and carbon when the blow-in temperature of the high-concentration hydrogen-containing gas containing 80 mol% or more of hydrogen gas is a predetermined value. The hydrogen in high-concentration hydrogen-containing gas, which is the correlation with the carbon consumption parameter related to the consumption amount, is obtained in advance for each tuyere temperature, and the carbon consumption is reduced compared to the current operation. A method for operating a blast furnace is characterized in that the amount of gas blown is determined based on the amount of blown-carbon consumption parameter correlation, and high-concentration hydrogen-containing gas is blown from the tuyere at the determined amount of blown hydrogen. Provided.
　また、高濃度水素含有ガス中の水素ガスの吹込み量－炭素消費パラメータ相関を高濃度水素含有ガスの吹込み温度毎に求めてもよい。 Further, the hydrogen gas injection amount-carbon consumption parameter correlation in the high-concentration hydrogen-containing gas may be obtained for each injection temperature of the high-concentration hydrogen-containing gas.
　また、高濃度水素含有ガスの吹込み温度が所定値であるときの、高濃度水素含有ガス中の水素ガスの吹込み量とベース操業に対する圧力損失の変化量との相関である吹込み量－圧力損失変化量相関を羽口前温度毎に予め求めておき、現状の操業よりも炭素消費量が低減し、かつ、圧力損失の変化量が所定範囲内の値となる高濃度水素含有ガス中の水素ガスの吹込み量を当該吹込み量－炭素消費パラメータ相関及び当該吹込み量－圧力損失変化量相関に基づいて決定してもよい。 Further, when the blowing temperature of the high-concentration hydrogen-containing gas is a predetermined value, the blowing amount which is the correlation between the blowing amount of the hydrogen gas in the high-concentration hydrogen-containing gas and the change amount of the pressure loss with respect to the base operation- In a high-concentration hydrogen-containing gas in which the correlation of the amount of change in pressure loss is obtained in advance for each tuyere temperature, the carbon consumption is reduced compared to the current operation, and the amount of change in pressure loss is within a predetermined range. The amount of hydrogen gas blown in may be determined based on the blown amount-carbon consumption parameter correlation and the blown amount-pressure loss change amount correlation.
　また、高濃度水素含有ガスの吹込み温度が所定値であるときの、高濃度水素含有ガス中の水素ガスの吹込み量とベース操業に対する炉頂ガス温度の変化量との相関である吹込み量－炉頂ガス温度変化量相関を羽口前温度毎に予め求めておき、現状の操業よりも炭素消費量が低減し、かつ、炉頂ガス温度の変化量が所定範囲内の値となる高濃度水素含有ガス中の水素ガスの吹込み量を当該吹込み量－炭素消費パラメータ相関及び当該吹込み量－炉頂ガス温度変化量相関に基づいて決定してもよい。 Further, when the blowing temperature of the high-concentration hydrogen-containing gas is a predetermined value, the blowing amount of the hydrogen gas in the high-concentration hydrogen-containing gas is correlated with the change amount of the furnace top gas temperature with respect to the base operation. The correlation between the amount and the amount of change in the temperature of the top gas is obtained in advance for each tuyere temperature, and the carbon consumption is reduced compared to the current operation, and the amount of change in the top gas temperature is within the specified range. The blown amount of hydrogen gas in the high-concentration hydrogen-containing gas may be determined based on the blown amount-carbon consumption parameter correlation and the blown amount-furnace top gas temperature change amount correlation.
　以上説明した通り、本発明の上記観点によれば、高炉操業を安定に維持しつつ羽口から吹き込まれる還元ガスとしての高濃度水素含有ガスの吹込み量を増加し、ＣＯ２排出量をさらに削減することが可能となる。 As described above, according to the above viewpoint of the present invention, the amount of high-concentration hydrogen-containing gas blown from the tuyere is increased while maintaining stable blast furnace operation, and the amount of CO 2 emissions is further increased. It is possible to reduce it.
高濃度水素含有ガスの吹込み温度を説明するための図である。It is a figure for demonstrating the blowing temperature of a high-concentration hydrogen-containing gas. 常温の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を羽口前温度Ｔｆ毎に示すグラフである。It is a graph which shows the correlation between the blow-in amount of pure hydrogen gas at room temperature and the reduction rate Input ΔC of a carbon consumption basic unit for each tuyere temperature Tf. ３００℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を羽口前温度Ｔｆ毎に示すグラフである。It is a graph which shows the correlation between the amount of pure hydrogen gas blown at 300 degreeC and the reduction rate Input ΔC of a carbon consumption basic unit for every tuyere temperature Tf. ３５０℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を示すグラフである。It is a graph which shows the correlation between the amount of pure hydrogen gas blown at 350 degreeC, and the reduction rate Input ΔC of a carbon consumption basic unit. ６００℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を羽口前温度Ｔｆ毎に示すグラフである。It is a graph which shows the correlation between the amount of pure hydrogen gas blown at 600 degreeC, and the reduction rate Input ΔC of a carbon consumption basic unit for every tuyere temperature Tf. ６５０℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を示すグラフである。It is a graph which shows the correlation between the amount of pure hydrogen gas blown at 650 ° C., and the reduction rate Input ΔC of a carbon consumption intensity. ９００℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を羽口前温度Ｔｆ毎に示すグラフである。It is a graph which shows the correlation between the amount of pure hydrogen gas blown at 900 degreeC and the reduction rate of carbon consumption basic unit Input ΔC for each tuyere temperature Tf. ９５０℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を示すグラフである。It is a graph which shows the correlation between the amount of pure hydrogen gas blown at 950 ° C., and the reduction rate Input ΔC of a carbon consumption intensity. １２００℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を羽口前温度Ｔｆ毎に示すグラフである。It is a graph which shows the correlation between the amount of pure hydrogen gas blown at 1200 degreeC and the reduction rate of carbon consumption basic unit Input ΔC for every tuyere temperature Tf. １２５０℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を示すグラフである。It is a graph which shows the correlation between the amount of pure hydrogen gas blown at 1250 ° C. and the reduction rate Input ΔC of a carbon consumption intensity. 常温の純水素ガスの吹込み量または常温の８０ｍｏｌ％Ｈ２－２０ｍｏｌ％Ｎ２高濃度水素含有ガス中の水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を示すグラフである。Shows the correlation between the reduction ratio Input △ C blow amount or ambient of 80mol% H 2 -20mol% N 2 high density blow amount and carbon consumption rate of hydrogen gas in the hydrogen-containing gas in the pure hydrogen gas at room temperature It is a graph. 常温の純水素ガスの吹込み量と圧力損失の変化量との相関を羽口前温度Ｔｆ毎に示すグラフである。It is a graph which shows the correlation between the blow-in amount of pure hydrogen gas at room temperature and the change amount of a pressure loss for each tuyere temperature Tf. 常温の純水素ガスの吹込み量と炉頂ガス温度の変化量との相関を羽口前温度Ｔｆ毎に示すグラフである。It is a graph which shows the correlation between the blow-in amount of pure hydrogen gas at room temperature and the change amount of the furnace top gas temperature for each tuyere temperature Tf. 羽口前温度Ｔｆが２１００℃となる際の、１２００℃の純水素ガスの吹込み量と圧力損失の変化量との相関を示すグラフである。It is a graph which shows the correlation between the amount of pure hydrogen gas blown at 1200 degreeC, and the amount of change of a pressure loss when the tuyere temperature Tf becomes 2100 degreeC. 純水素ガスの吹込み温度と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを１０％とするために必要な純水素ガスの吹込み量との相関を示すグラフである。It is a graph which shows the correlation between the blowing temperature of pure hydrogen gas and the blowing amount of pure hydrogen gas required to make the reduction rate Input ΔC of carbon consumption intensity 10%. 純水素ガスの吹込み温度と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを２０％とするために必要な純水素ガスの吹込み量との相関を示すグラフである。It is a graph which shows the correlation between the blowing temperature of pure hydrogen gas and the blowing amount of pure hydrogen gas required to make the reduction rate Input ΔC of carbon consumption intensity 20%.
　以下に添付図面を参照しながら、本発明の好適な実施の形態について詳細に説明する。なお、本実施形態において、「～」を用いて表される数値範囲は、「～」の前後に記載される数値を下限値及び上限値として含む範囲を意味する。また、「還元材比」は、溶銑１トンを製造するのに要した還元材の合計質量である。したがって、還元材比は基本的には溶銑１トンを製造するのに要したコークス及び微粉炭の合計質量であり、高濃度水素含有ガス中の炭素含有還元ガスの質量は還元材比には含まれないものとして扱っている。また、「炭素消費原単位（Ｉｎｐｕｔ　Ｃ）」は、溶銑１トンを製造するのに要した炭素（すなわち溶銑１トンあたりの炭素消費量）である。「炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃ」は、高濃度水素含有ガスを吹き込まない操業であるベース操業に対する炭素消費原単位の削減割合を意味する。単位ｋｇ／ｔでのベース操業のＩｎｐｕｔ　ＣをＡ、単位ｋｇ／ｔでのある操業時のＩｎｐｕｔ　ＣをＢとすると、Ｉｎｐｕｔ　△Ｃは、以下の数式で示される。
　Ｉｎｐｕｔ　△Ｃ＝（Ａ－Ｂ）／Ａ×１００（％）
　炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが大きいほど、還元材比も削減され、ひいては、ＣＯ２排出量が削減される。 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present embodiment, the numerical range represented by using "-" means a range including the numerical values before and after "-" as the lower limit value and the upper limit value. The "reducing agent ratio" is the total mass of the reducing agents required to produce 1 ton of hot metal. Therefore, the reducing agent ratio is basically the total mass of coke and pulverized coal required to produce 1 ton of hot metal, and the mass of the carbon-containing reducing gas in the high-concentration hydrogen-containing gas is included in the reducing agent ratio. It is treated as something that cannot be done. The "carbon consumption intensity (Input C)" is the carbon required to produce 1 ton of hot metal (that is, the amount of carbon consumed per ton of hot metal). “Reduction ratio of carbon consumption intensity Input ΔC” means the reduction ratio of carbon consumption intensity to the base operation which is an operation in which a high concentration hydrogen-containing gas is not blown. Assuming that the Input C of the base operation at the unit kg / t is A and the Input C at the time of the operation at the unit kg / t is B, the Input ΔC is expressed by the following mathematical formula.
Input ΔC = (AB) / A × 100 (%)
The larger the reduction rate of the carbon consumption intensity, the smaller the ratio of the reducing agent, and the more the CO 2 emission is reduced.
　＜１．本発明者による知見＞
　本発明者は、上記の課題を解決するため、還元ガスとして高濃度水素含有ガスに着目した。ここで、本実施形態における高濃度水素含有ガスとは、水素ガスを８０ｍｏｌ％（高濃度水素含有ガスを構成するすべてのガスの総物質量に対する水素ガスのｍｏｌ％）以上含有するガスを意味する。純水素ガス（水素ガス濃度が１００ｍｏｌ％となるガス）は高濃度水素含有ガスに含まれる。 <1. Findings by the Inventor>
In order to solve the above problems, the present inventor has focused on a high-concentration hydrogen-containing gas as a reducing gas. Here, the high-concentration hydrogen-containing gas in the present embodiment means a gas containing 80 mol% or more of hydrogen gas (mol% of hydrogen gas with respect to the total amount of substances of all the gases constituting the high-concentration hydrogen-containing gas). .. Pure hydrogen gas (gas having a hydrogen gas concentration of 100 mol%) is included in the high-concentration hydrogen-containing gas.
　そして、本発明者は、高濃度水素含有ガス中の水素ガスの吹込み量（以下、単に吹込み量ともいう）及び高濃度水素含有ガスの吹込み温度に着目した。高濃度水素含有ガス中の水素ガスによる鉄系原料の還元反応は吸熱反応である。吸熱反応による温度低下を補償するためには、当該水素ガスの吹込み温度を上げることが考えられる。しかしながら、高濃度水素含有ガス中の水素ガスを多量に吹き込んだ場合の炉内温度の低下量やその炉内温度の低下量に応じて求められる熱補償の程度等を把握することは非常に困難であり、これらについての詳細な検討はこれまで行われていなかった。上記の事項について、本発明者らによって初めて詳細な検討が行われた。具体的には、高濃度水素含有ガス中の水素ガスとＣＯガス等の様々なガス組成および高濃度水素含有ガスの様々な吹込み温度での還元反応速度の把握、ならびに、これらのガスの還元反応熱により変化する炉内温度による還元反応速度への影響および還元反応によって変化するガス組成による還元反応速度への影響の把握が行われ、その上で、還元反応速度が低下しない程度の熱量の把握が炉内全体に対して行われた。このような検討は、高炉実機での複数回の試験の実施、試験高炉レベルの装置を用い、断熱条件を模擬しつつ高炉炉内のガスを高炉炉内条件で吹込み可能な実験装置を用いた実験、または、シミュレーションモデルによる検討が必要になる。本発明者らは、シミュレーションモデルによって上記検討を行い、この結果、吹込み温度毎に吹込み量の適正範囲が存在することを見出した。
　つまり、高濃度水素含有ガスの吹込み温度が６００℃以下の場合、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは、高濃度水素含有ガス中の水素ガスの吹込み量の増加に伴って単純に増加するものではなく、当該吹込み量がある程度増加すると緩和し減少に転じる。そして、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが緩和し減少に転じる際の高濃度水素含有ガス中の水素ガスの吹込み量は高濃度水素含有ガスの吹込み温度によって異なる。一方で、高濃度水素含有ガスの吹込み温度が６００℃超となる場合、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは、吹込み量の増加に伴って増加する傾向がある。高濃度水素含有ガス中の水素ガスの吹込み量がある程度大きくなると、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが例えば７％以上となる。したがって、この適正範囲の水素ガスの吹込み量に従って決定される高濃度水素含有ガスの吹込み量を高炉に吹き込むことで、ＣＯ２排出量を大きく削減することができる。例えば、後述する実施例に示される通り、高炉の操業時の炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを７％以上とすることができ、ひいてはＣＯ２排出量を大きく削減することができる。本発明者は、このような知見に基づいて本実施形態に係る高炉の操業方法に想到した。以下、本実施形態について詳細に説明する。 Then, the present inventor paid attention to the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas (hereinafter, also simply referred to as the amount of blown hydrogen) and the blowing temperature of the high-concentration hydrogen-containing gas. The reduction reaction of an iron-based raw material by hydrogen gas in a high-concentration hydrogen-containing gas is an endothermic reaction. In order to compensate for the temperature drop due to the endothermic reaction, it is conceivable to raise the blowing temperature of the hydrogen gas. However, it is very difficult to grasp the amount of decrease in the temperature inside the furnace when a large amount of hydrogen gas in the high-concentration hydrogen-containing gas is blown in, and the degree of heat compensation required according to the amount of decrease in the temperature inside the furnace. Therefore, detailed examination of these has not been conducted so far. For the first time, the present inventors have conducted a detailed study on the above matters. Specifically, the composition of various gases such as hydrogen gas and CO gas in the high-concentration hydrogen-containing gas and the reduction reaction rate of the high-concentration hydrogen-containing gas at various blowing temperatures are grasped, and the reduction of these gases is performed. The effect of the furnace temperature, which changes due to the reaction heat, on the reduction reaction rate and the effect of the gas composition, which changes due to the reduction reaction, on the reduction reaction rate are grasped, and then the amount of heat is such that the reduction reaction rate does not decrease. Grasp was done for the entire reactor. For such a study, multiple tests were conducted on the actual blast furnace machine, and an experimental device capable of blowing gas in the blast furnace under the conditions inside the blast furnace while simulating the adiabatic conditions was used using the equipment at the test blast furnace level. It is necessary to examine the experiment or simulation model. The present inventors conducted the above study using a simulation model, and as a result, found that there is an appropriate range of the blowing amount for each blowing temperature.
That is, when the blowing temperature of the high-concentration hydrogen-containing gas is 600 ° C. or lower, the reduction rate of carbon consumption intensity Input ΔC is simply as the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas increases. It does not increase, but when the amount of blown air increases to some extent, it eases and begins to decrease. The amount of hydrogen gas blown into the high-concentration hydrogen-containing gas when the reduction rate of the carbon consumption intensity is relaxed and starts to decrease differs depending on the blowing temperature of the high-concentration hydrogen-containing gas. On the other hand, when the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C., the reduction rate Input ΔC of the carbon consumption intensity tends to increase as the blowing amount increases. When the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas increases to some extent, the reduction rate of carbon consumption intensity, Input ΔC, becomes, for example, 7% or more. Therefore, CO 2 emissions can be significantly reduced by blowing the amount of high-concentration hydrogen-containing gas blown into the blast furnace, which is determined according to the amount of hydrogen gas blown in this appropriate range. For example, as shown in Examples described later, the reduction rate of carbon consumption intensity during operation of the blast furnace can be set to 7% or more, and CO 2 emissions can be significantly reduced. Based on such findings, the present inventor has come up with a method for operating a blast furnace according to the present embodiment. Hereinafter, the present embodiment will be described in detail.
　＜２．高濃度水素含有ガスの組成＞
　本実施形態に係る高炉の操業方法では、高濃度水素含有ガスを羽口から吹き込む。そこで、まず、高濃度水素含有ガスの組成について説明する。高濃度水素含有ガスは、上述したように水素ガスを８０ｍｏｌ％以上含有するガスである。高濃度水素含有ガスには純水素ガスが含まれる。高濃度水素含有ガスには、水素ガス以外の他のガス、例えば上述した炭素含有還元ガス（例えば炭化水素ガス）、ＣＯガス、ＣＯ２ガス、Ｈ２Ｏガス、Ｎ２ガス等を含んでいてもよい。ただし、他のガスの濃度は合計で２０ｍｏｌ％未満となる。 <2. Composition of high-concentration hydrogen-containing gas>
In the operation method of the blast furnace according to the present embodiment, a high-concentration hydrogen-containing gas is blown from the tuyere. Therefore, first, the composition of the high-concentration hydrogen-containing gas will be described. The high-concentration hydrogen-containing gas is a gas containing 80 mol% or more of hydrogen gas as described above. The high-concentration hydrogen-containing gas includes pure hydrogen gas. The high-concentration hydrogen-containing gas includes gases other than hydrogen gas, such as the above-mentioned carbon-containing reducing gas (for example, hydrocarbon gas), CO gas, CO 2 gas, H 2 O gas, N 2 gas and the like. May be good. However, the total concentration of other gases is less than 20 mol%.
　他のガスの濃度が合計で２０ｍｏｌ％以上であるガスは本実施形態における高濃度水素含有ガスには含まれない。他のガスの濃度が２０ｍｏｌ％以上である場合、ＣＯ２ガスの削減量が大きく低下するからである。例えば、他のガスのうち、炭化水素ガス、ＣＯ２ガス、Ｈ２Ｏガスは、羽口先で分解される際に吸熱反応を生じるため、高炉内における還元効率が下がる。このため、還元されずに高炉炉下部に到達する鉄系原料が増加する。したがって、コークスによる直接還元反応量が多くなる。したがって、高炉内の温度を維持するために多くの還元材が必要になるので、ＣＯ２ガスの削減量が大きく低下する。例えば、水素ガスを５０ｍｏｌ％含むＣＯＧ（コークス炉ガス）を６００Ｎｍ３／ｔの吹込み量で高炉内に吹き込む場合、水素ガスを３００Ｎｍ３／ｔの吹込み量で高炉内に吹き込むことになる。このときのＣＯ２排出量の削減効果は、純水素ガスを３００Ｎｍ３／ｔの吹込み量で高炉内に吹き込んだときと比べて大きく劣り、抜本的なＣＯ２排出量削減（例えば炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃ≧７％）にはつながらない。なお、後述する実施例で示されるように、常温の純水素ガスの例では、吹込み量が３００Ｎｍ３／ｔ程度でＣＯ２排出量の削減効果が最大となる。 Gases having a total concentration of 20 mol% or more of other gases are not included in the high-concentration hydrogen-containing gas in the present embodiment. This is because when the concentration of the other gas is 20 mol% or more, the amount of CO 2 gas reduction is greatly reduced. For example, among other gases, hydrocarbon gas, CO 2 gas, and H 2 O gas cause an endothermic reaction when they are decomposed at the tuyere tip, so that the reduction efficiency in the blast furnace is lowered. Therefore, the amount of iron-based raw materials that reach the lower part of the blast furnace without being reduced increases. Therefore, the amount of direct reduction reaction by coke increases. Therefore, since a large amount of reducing agent is required to maintain the temperature in the blast furnace, the amount of CO 2 gas reduction is greatly reduced. For example, when COG (coke oven gas) containing 50 mol% of hydrogen gas is blown into the blast furnace with a blowing amount of 600 Nm 3 / t, hydrogen gas is blown into the blast furnace with a blown amount of 300 Nm 3 / t. The effect of reducing CO 2 emissions at this time is significantly inferior to that when pure hydrogen gas is blown into the blast furnace at a flow rate of 300 Nm 3 / t, and the effect of drastically reducing CO 2 emissions (for example, carbon consumption source) is significantly inferior. It does not lead to the reduction rate of the unit, Input ΔC ≧ 7%). As shown in Examples described later, in the example of pure hydrogen gas at room temperature, the effect of reducing CO 2 emissions is maximized when the blown amount is about 300 Nm 3 / t.
　＜３．高炉の操業方法＞
　つぎに、本実施形態に係る高炉の操業方法について説明する。本実施形態に係る高炉の操業方法では、まず、高濃度水素含有ガスの吹込み温度を常温以上の範囲内で決定する。 <3. How to operate the blast furnace ＞
Next, the operation method of the blast furnace according to the present embodiment will be described. In the operation method of the blast furnace according to the present embodiment, first, the blowing temperature of the high-concentration hydrogen-containing gas is determined within the range of room temperature or higher.
　ここで、図１を参照して、高濃度水素含有ガスの吹込み温度（以下、これを単に「吹込み温度」と言うことがある。）について説明する。図１は、吹込み温度を説明するための図である。高濃度水素含有ガスは、例えば、ヒーター５を備えるガスタンク３でその温度が調節される。つまり、高濃度水素含有ガスは、ガスタンク３内でヒーター５によって加熱された後、または、常温の場合には非加熱のまま、高炉１の炉下部に設けられた熱風吹込み用の羽口２に送られる。羽口２に送られた高濃度水素含有ガスは、羽口２から高炉１内に吹き込まれることができる。具体的には、羽口２に送られた高濃度水素含有ガスは、熱風炉４で発生した熱風と混合（合流）された後、羽口２から高炉１内に吹き込まれる。吹込み温度は、羽口２から高炉１内に吹き込まれる際の熱風と混合される直前の高濃度水素含有ガスの温度である。実際の操業（実炉）では、例えば、高濃度水素含有ガスを加熱するヒーター５から高炉１内に吹き込まれるまでの温度低下がないため、ヒーター５の設定温度を吹込み温度とすることができる。熱風と高濃度水素含有ガスとが混合されることで高濃度水素含有ガスの温度は上昇するが、このときの温度は本実施形態における吹込み温度ではない。また、特許文献１では、送風温度は記載されているが、特許文献１の送風温度は本実施形態での吹込み温度とは異なるものである。 Here, with reference to FIG. 1, the blowing temperature of the high-concentration hydrogen-containing gas (hereinafter, this may be simply referred to as “blowing temperature”) will be described. FIG. 1 is a diagram for explaining the blowing temperature. The temperature of the high-concentration hydrogen-containing gas is adjusted, for example, in a gas tank 3 provided with a heater 5. That is, the high-concentration hydrogen-containing gas is heated by the heater 5 in the gas tank 3 or remains unheated at room temperature, and the tuyere 2 for blowing hot air provided in the lower part of the blast furnace 1 is provided. Will be sent to. The high-concentration hydrogen-containing gas sent to the tuyere 2 can be blown into the blast furnace 1 from the tuyere 2. Specifically, the high-concentration hydrogen-containing gas sent to the tuyere 2 is mixed (merged) with the hot air generated in the hot air furnace 4 and then blown into the blast furnace 1 from the tuyere 2. The blowing temperature is the temperature of the high-concentration hydrogen-containing gas immediately before being mixed with the hot air when it is blown into the blast furnace 1 from the tuyere 2. In actual operation (actual furnace), for example, since there is no temperature drop from the heater 5 that heats the high-concentration hydrogen-containing gas until it is blown into the blast furnace 1, the set temperature of the heater 5 can be set as the blowing temperature. .. The temperature of the high-concentration hydrogen-containing gas rises due to the mixing of the hot air and the high-concentration hydrogen-containing gas, but the temperature at this time is not the blowing temperature in the present embodiment. Further, although Patent Document 1 describes the blowing temperature, the blowing temperature of Patent Document 1 is different from the blowing temperature in the present embodiment.
　後述する実施例で示されるとおり、高濃度水素含有ガスを加熱せずに常温のまま羽口から吹込む場合にもＣＯ２排出量を大きく削減することができる（図２参照）。図２は、常温の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を羽口前温度Ｔｆ毎に示すグラフである。このグラフは高炉操業シミュレーションによって得られるものである。詳細は実施例で説明するが、ここではＫｏｕｊｉ　ＴＡＫＡＴＡＮＩ、Ｔａｋａｎｏｂｕ　ＩＮＡＤＡ、Ｙｕｔａｋａ　ＵＪＩＳＡＷＡ、「Ｔｈｒｅｅ－ｄｉｍｅｎｓｉｏｎａｌ　Ｄｙｎａｍｉｃ　Ｓｉｍｕｌａｔｏｒ　ｆｏｒ　Ｂｌａｓｔ　Ｆｕｒｎａｃｅ」、ＩＳＩＪ　Ｉｎｔｅｒｎａｔｉｏｎａｌ、Ｖｏｌ．３９（１９９９）、Ｎｏ．１、ｐ．１５－２２などに示される、所謂「高炉数学モデル」を用いた。この高炉数学モデルは、概略的には、高炉の内部領域を高さ方向、径方向、周方向に分割することで複数のメッシュ（小領域）を規定し、各メッシュの挙動をシミュレーションするものである。シミュレーションの条件は後述する実施例と同様とした。図２に示されるように、常温の純水素ガスの吹込み量が２００～５００Ｎｍ３／ｔとなる場合に炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを例えば７％以上にすることが可能となる。炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは好ましくは８％以上である。なお、本実施形態における「常温」とは、非加熱の状態を意味し、具体的には５℃以上３５℃以下の温度とする。 As shown in Examples described later, CO 2 emissions can be significantly reduced even when the high-concentration hydrogen-containing gas is blown from the tuyere at room temperature without heating (see FIG. 2). FIG. 2 is a graph showing the correlation between the amount of pure hydrogen gas blown at room temperature and the reduction rate of carbon consumption intensity Input ΔC for each tuyere temperature Tf. This graph is obtained by blast furnace operation simulation. Details will be described in Examples, but here, Koji TAKATANI, Takanobu INADA, Yutaka UJISAWA, "Three-dimensional Dynamic Simulation for Blast Furnace", ISIJ International. 39 (1999), No. 1, p. The so-called "blast furnace mathematical model" shown in 15-22 and the like was used. This blast furnace mathematical model roughly defines a plurality of meshes (small regions) by dividing the internal region of the blast furnace into the height direction, the radial direction, and the circumferential direction, and simulates the behavior of each mesh. is there. The simulation conditions were the same as in the examples described later. As shown in FIG. 2, when the amount of pure hydrogen gas blown at room temperature is 200 to 500 Nm 3 / t, the reduction rate of carbon consumption intensity can be set to 7% or more, for example. .. The reduction rate of carbon consumption intensity Input ΔC is preferably 8% or more. The "room temperature" in the present embodiment means a non-heated state, and specifically, the temperature is 5 ° C. or higher and 35 ° C. or lower.
　詳細は後述するが、吹込み温度が常温以上の範囲内において、同一の吹込み量に対する炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは高濃度水素含有ガスの吹込み温度が高いほど大きくなる（図２～図１０参照）。図３は、３００℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を羽口前温度Ｔｆ毎に示すグラフである。図４は、３５０℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を示すグラフである。図５は、６００℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を羽口前温度Ｔｆ毎に示すグラフである。図６は、６５０℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を示すグラフである。図７は、９００℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を羽口前温度Ｔｆ毎に示すグラフである。図８は、９５０℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を示すグラフである。図９は、１２００℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を羽口前温度Ｔｆ毎に示すグラフである。図１０は、１２５０℃の純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を示すグラフである。 Details will be described later, but when the blowing temperature is within the range of room temperature or higher, the reduction ratio of carbon consumption intensity to the same blowing amount Input ΔC increases as the blowing temperature of the high-concentration hydrogen-containing gas increases (Fig.). 2 to 10). FIG. 3 is a graph showing the correlation between the amount of pure hydrogen gas blown at 300 ° C. and the reduction rate of carbon consumption intensity Input ΔC for each tuyere temperature Tf. FIG. 4 is a graph showing the correlation between the amount of pure hydrogen gas blown at 350 ° C. and the reduction rate Input ΔC of the carbon consumption intensity. FIG. 5 is a graph showing the correlation between the amount of pure hydrogen gas blown at 600 ° C. and the reduction rate of carbon consumption intensity Input ΔC for each tuyere temperature Tf. FIG. 6 is a graph showing the correlation between the amount of pure hydrogen gas blown at 650 ° C. and the reduction rate Input ΔC of the carbon consumption intensity. FIG. 7 is a graph showing the correlation between the amount of pure hydrogen gas blown at 900 ° C. and the reduction rate of carbon consumption intensity Input ΔC for each tuyere temperature Tf. FIG. 8 is a graph showing the correlation between the amount of pure hydrogen gas blown at 950 ° C. and the reduction rate Input ΔC of the carbon consumption intensity. FIG. 9 is a graph showing the correlation between the amount of pure hydrogen gas blown at 1200 ° C. and the reduction rate of carbon consumption intensity Input ΔC for each tuyere temperature Tf. FIG. 10 is a graph showing the correlation between the amount of pure hydrogen gas blown at 1250 ° C. and the reduction rate Input ΔC of the carbon consumption intensity.
　これらのグラフは上述した高炉操業シミュレーションによって得られるものである。詳細は実施例で説明する。図３～図１０の炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは図２の炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃよりも高いことがわかる。高濃度水素含有ガスの吹込み温度が高いほど、高炉内で生じたボッシュガス（窒素ガス、水素ガス、及びＣＯガスの混合ガス）の顕熱が高くなるので、より多くの還元ガスが鉄系原料を還元すると考えられる。すなわち、還元効率が高くなる。このため、高濃度水素含有ガスの吹込み温度が高いほど炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが大きくなると考えられる。したがって、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを高めるという観点からは、高濃度水素含有ガスの吹込み温度を高くすることが好ましい。具体的には、吹込み温度を３００℃超の範囲内で決定することが好ましく、６００℃超の範囲内で決定することがより好ましく、９００℃超の範囲内で決定することがより好ましい。 These graphs are obtained by the above-mentioned blast furnace operation simulation. Details will be described in Examples. It can be seen that the reduction ratio of the carbon consumption intensity of FIGS. 3 to 10 Input ΔC is higher than the reduction ratio of the carbon consumption intensity of FIG. 2 Input ΔC. The higher the blowing temperature of the high-concentration hydrogen-containing gas, the higher the apparent heat of the bosh gas (mixed gas of nitrogen gas, hydrogen gas, and CO gas) generated in the blast furnace. It is thought that the raw material is reduced. That is, the reduction efficiency is high. Therefore, it is considered that the higher the blowing temperature of the high-concentration hydrogen-containing gas, the larger the reduction rate Input ΔC of the carbon consumption intensity. Therefore, from the viewpoint of increasing the reduction rate Input ΔC of the carbon consumption intensity, it is preferable to increase the blowing temperature of the high-concentration hydrogen-containing gas. Specifically, it is preferable to determine the blowing temperature in the range of more than 300 ° C., more preferably in the range of more than 600 ° C., and more preferably in the range of more than 900 ° C.
　ただし、高濃度水素含有ガスの吹込み温度を６００℃超とするためには、大規模な設備改造が必要になる場合がある。このため、既存の設備では高濃度水素含有ガスの吹込み温度を６００℃超とすることが難しい場合には、高濃度水素含有ガスの吹込み温度を常温～６００℃の範囲内で決定してもよい。一方で、既存の設備で（あるいは既存の設備の改造により）高濃度水素含有ガスの吹込み温度を６００℃超とすることができる場合には、６００℃超の範囲内で高濃度水素含有ガスの吹込み温度を決定してもよい。 However, in order to raise the blowing temperature of high-concentration hydrogen-containing gas to over 600 ° C, large-scale equipment modification may be required. Therefore, when it is difficult to set the blowing temperature of the high-concentration hydrogen-containing gas to more than 600 ° C with the existing equipment, determine the blowing temperature of the high-concentration hydrogen-containing gas within the range of room temperature to 600 ° C. May be good. On the other hand, if the blow-in temperature of the high-concentration hydrogen-containing gas can be made higher than 600 ° C in the existing equipment (or by modifying the existing equipment), the high-concentration hydrogen-containing gas is in the range of more than 600 ° C. The blowing temperature may be determined.
　ついで、高濃度水素含有ガス中の水素ガスの吹込み量を決定する。ここで、高濃度水素含有ガス中の水素ガスの吹込み量は、羽口から高炉内に吹き込まれる高濃度水素含有ガス中の水素ガスの溶銑１トン当たりの流量であり、単位はＮｍ３／ｔである。高濃度水素含有ガスが純水素ガスであるとき、高濃度水素含有ガス中の水素ガスの吹込み量は高濃度水素含有ガスの吹込み量に等しい。高濃度水素含有ガスが水素ガス以外の他のガスを含む混合ガスであるとき、高濃度水素含有ガス中の水素ガスの吹込み量は、単位ｍｏｌ％での、高濃度水素含有ガスの吹込み量に水素ガスの比率を乗じた量となる。実際の操業では、高濃度水素含有ガスの供給源（例えばガスタンク）の排出口に設けられた流量計が示す値と単位ｍｏｌ％での高濃度水素含有ガス中の水素ガスの比率から高濃度水素含有ガス中の水素ガスの吹込み量を算出する。 Then, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is determined. Here, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is the flow rate per ton of the hot metal of the hydrogen gas in the high-concentration hydrogen-containing gas blown into the blast furnace from the tuyere, and the unit is Nm 3 /. t. When the high-concentration hydrogen-containing gas is pure hydrogen gas, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is equal to the amount of high-concentration hydrogen-containing gas blown. When the high-concentration hydrogen-containing gas is a mixed gas containing a gas other than hydrogen gas, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is in units of mol%. It is the amount obtained by multiplying the amount by the ratio of hydrogen gas. In actual operation, high-concentration hydrogen is obtained from the value indicated by the flow meter provided at the outlet of the high-concentration hydrogen-containing gas supply source (for example, a gas tank) and the ratio of hydrogen gas in the high-concentration hydrogen-containing gas in units of mol%. Calculate the amount of hydrogen gas blown into the contained gas.
　本実施形態では、高濃度水素含有ガスの吹込み温度で場合分けして吹込み量を決定する。具体的には、吹込み温度が常温～３００℃となる場合には、高濃度水素含有ガス中の水素ガスの吹込み量を２００～５００Ｎｍ３／ｔの範囲内で決定する。一方で、吹込み温度が３００℃超６００℃以下となる場合には、高濃度水素含有ガス中の水素ガスの吹込み量を１４５Ｎｍ３／ｔの範囲内で決定する。高濃度水素含有ガスの吹込み温度が６００℃超９００℃以下となる場合には、高濃度水素含有ガスの吹込み量を１２５Ｎｍ３／ｔ以上の範囲内で決定する。高濃度水素含有ガスの吹込み温度が９００℃超１２００℃以下となる場合には、高濃度水素含有ガス中の水素ガスの吹込み量を１１０Ｎｍ３／ｔ以上の範囲内で決定する。高濃度水素含有ガスの吹込み温度が１２００℃超となる場合、高濃度水素含有ガス中の水素ガスの吹込み量を１００Ｎｍ３／ｔ以上の範囲内で決定する。 In the present embodiment, the blowing amount is determined for each case according to the blowing temperature of the high-concentration hydrogen-containing gas. Specifically, when the blowing temperature is room temperature to 300 ° C., the blowing amount of hydrogen gas in the high-concentration hydrogen-containing gas is determined within the range of 200 to 500 Nm 3 / t. On the other hand, when the blowing temperature is more than 300 ° C. and 600 ° C. or lower, the blowing amount of hydrogen gas in the high-concentration hydrogen-containing gas is determined within the range of 145 Nm 3 / t. When the blowing temperature of the high-concentration hydrogen-containing gas is more than 600 ° C. and 900 ° C. or lower, the blowing amount of the high-concentration hydrogen-containing gas is determined within the range of 125 Nm 3 / t or more. When the blowing temperature of the high-concentration hydrogen-containing gas is more than 900 ° C. and 1200 ° C. or lower, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is determined within the range of 110 Nm 3 / t or more. When the blowing temperature of the high-concentration hydrogen-containing gas exceeds 1200 ° C., the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is determined within the range of 100 Nm 3 / t or more.
　このように吹込み温度で場合分けするのは、吹込み温度によって好適な吹込み量がやや異なるからである。なお、以下の説明では高濃度水素含有ガスが純水素ガスである場合を一例として説明するが、後述する実施例１－２に示される通り、高濃度水素含有ガスに水素ガス以外のガスが含まれる場合であっても、高濃度水素含有ガスの吹込み温度と好適な吹込み量との相関は変わらない。 The reason why the cases are classified according to the blowing temperature in this way is that the suitable blowing amount differs slightly depending on the blowing temperature. In the following description, the case where the high-concentration hydrogen-containing gas is pure hydrogen gas will be described as an example, but as shown in Example 1-2 described later, the high-concentration hydrogen-containing gas contains a gas other than hydrogen gas. Even in this case, the correlation between the blowing temperature of the high-concentration hydrogen-containing gas and the suitable blowing amount does not change.
　図２及び図３に示すように、高濃度水素含有ガスの吹込み温度が常温～３００℃となる場合には、高濃度水素含有ガス中の水素ガスの吹込み量をベース操業の０から増加させていくと炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが増加する。そして、高濃度水素含有ガス中の水素ガスの吹込み量が３００Ｎｍ３／ｔ程度となる際に炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃがピークとなり、高濃度水素含有ガス中の水素ガスの吹込み量がさらに増加すると炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは減少に転じる。そして、高濃度水素含有ガス中の水素ガスの吹込み量が２００～５００Ｎｍ３／ｔの範囲内の値となる場合に、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを７％以上とすることが可能となる。なお、高濃度水素含有ガスが純水素ガスとなる場合、高濃度水素含有ガス中の水素ガスの吹込み量は、高濃度水素含有ガスの吹込み量となるが、高濃度水素含有ガスが水素ガス以外のガスを含む場合、この値は高濃度水素含有ガスの吹き込み量に水素ガスの比率（ｍｏｌ％）を乗じた量となる。 As shown in FIGS. 2 and 3, when the blowing temperature of the high-concentration hydrogen-containing gas is room temperature to 300 ° C., the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is increased from 0 in the base operation. If this is done, the reduction rate of carbon consumption intensity, Input ΔC, will increase. Then, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas reaches about 300 Nm 3 / t, the carbon consumption intensity reduction rate Input ΔC peaks, and the hydrogen gas blown into the high-concentration hydrogen-containing gas. When the amount of inclusion further increases, the reduction rate of carbon consumption intensity Input ΔC starts to decrease. Then, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is within the range of 200 to 500 Nm 3 / t, the reduction rate of carbon consumption intensity, Input ΔC, can be set to 7% or more. It will be possible. When the high-concentration hydrogen-containing gas becomes pure hydrogen gas, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is the amount of high-concentration hydrogen-containing gas blown, but the high-concentration hydrogen-containing gas is hydrogen. When a gas other than gas is included, this value is the amount obtained by multiplying the amount of high-concentration hydrogen-containing gas blown by the ratio of hydrogen gas (mol%).
　水素ガスによる鉄系原料の還元反応（すなわち水素還元反応）は吸熱反応である。このため、高濃度水素含有ガス中の水素ガスの吹込み量が３００Ｎｍ３／ｔを超えた場合には、かかる吸熱反応が炉内で多く生じ、炉内温度が低下すると考えられる。そして、このような炉内温度の低下により、水素ガスを含む還元ガスによる還元効率が低下すると考えられる。このような還元効率の低下を防ぐためには、還元材比を上げて操業を行う必要がある。このため、高濃度水素含有ガス中の水素ガスの吹込み量が３００Ｎｍ３／ｔを超えた場合に、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが減少に転じる。したがって、吹込み温度が常温～３００℃となる場合には、高濃度水素含有ガス中の水素ガスの吹込み量を２００～４００Ｎｍ３／ｔの範囲内で決定することが好ましく、２００～３００Ｎｍ３／ｔの範囲内で決定することがより好ましい。この場合、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを８％以上とすることが可能となる。 The reduction reaction of iron-based raw materials with hydrogen gas (that is, hydrogen reduction reaction) is an endothermic reaction. Therefore, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas exceeds 300 Nm 3 / t, it is considered that such an endothermic reaction occurs frequently in the furnace and the temperature inside the furnace drops. Then, it is considered that such a decrease in the temperature inside the furnace reduces the reduction efficiency by the reducing gas containing hydrogen gas. In order to prevent such a decrease in reducing efficiency, it is necessary to increase the ratio of reducing materials to carry out the operation. Therefore, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas exceeds 300 Nm 3 / t, the reduction rate Input ΔC of the carbon consumption intensity starts to decrease. Therefore, when the blowing temperature is room temperature to 300 ° C., it is preferable to determine the blowing amount of hydrogen gas in the high-concentration hydrogen-containing gas within the range of 200 to 400 Nm 3 / t, and it is preferable to determine 200 to 300 Nm 3 It is more preferable to determine within the range of / t. In this case, the reduction rate Input ΔC of the carbon consumption intensity can be set to 8% or more.
　図４及び図５に示すように、高濃度水素含有ガスの吹込み温度が３００℃超６００℃以下となる場合にも、高濃度水素含有ガス中の水素ガスの吹込み量をベース操業の０Ｎｍ３／ｔから増加させていくと炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが増加する。そして、高濃度水素含有ガス中の水素ガスの吹込み量が１４５Ｎｍ３／ｔ以上であると、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが７％以上となる。高濃度水素含有ガスの吹込み温度が６００℃の場合、図５に示すように、高濃度水素含有ガス中の水素ガスの吹込み量が６００Ｎｍ３／ｔ程度で炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが飽和する。高濃度水素含有ガスの吹込み温度が３５０℃の場合では、図４に示すように、高濃度水素含有ガス中の水素ガスの吹込み量が３００Ｎｍ３／ｔ程度となる際に炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃがピークとなり、高濃度水素含有ガス中の水素ガスの吹込み量がさらに増加すると炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは減少に転じる。
　なお、高濃度水素含有ガスの吹込み温度が３５０℃の場合、高濃度水素含有ガス中の水素ガスの吹込み量が６００Ｎｍ３／ｔを超えると、羽口先温度Ｔｆを２２００℃に維持することが困難になることがある。従来の高炉操業では、羽口前温度Ｔｆは２２００℃程度とされることが多く、羽口前温度Ｔｆが２２００℃に維持することが困難である場合、従来の高炉操業の操業条件と大きく操業条件を変更することになる。 As shown in FIGS. 4 and 5, even when the blowing temperature of the high-concentration hydrogen-containing gas is more than 300 ° C. and 600 ° C. or lower, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 0 Nm in the base operation. Increasing from 3 / t increases the reduction rate of carbon consumption intensity Input ΔC. When the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 145 Nm 3 / t or more, the reduction rate Input ΔC of the carbon consumption intensity is 7% or more. When the blowing temperature of the high-concentration hydrogen-containing gas is 600 ° C., as shown in FIG. 5, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is about 600 Nm 3 / t, and the reduction rate of carbon consumption intensity Imput. ΔC is saturated. When the blowing temperature of the high-concentration hydrogen-containing gas is 350 ° C., as shown in FIG. 4, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is about 300 Nm 3 / t, the carbon consumption intensity is the basic unit. When the reduction rate of Imput ΔC peaks and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas further increases, the reduction rate of carbon consumption intensity Imput ΔC starts to decrease.
When the blowing temperature of the high-concentration hydrogen-containing gas is 350 ° C., the tuyere temperature Tf should be maintained at 2200 ° C. when the blowing amount of the hydrogen gas in the high-concentration hydrogen-containing gas exceeds 600 Nm 3 / t. Can be difficult. In the conventional blast furnace operation, the tuyere temperature Tf is often set to about 2200 ° C., and when it is difficult to maintain the tuyere temperature Tf at 2200 ° C., the operation is largely different from the operating conditions of the conventional blast furnace operation. The conditions will be changed.
　高濃度水素含有ガスの吹込み温度が３５０℃の場合に炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが減少に転じる理由は上記と同様である。高濃度水素含有ガスの吹込み温度が６００℃の場合、吹込み量が７００Ｎｍ３／ｔまでの範囲では、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは減少には転じない。しかしながら、高濃度水素含有ガス中の水素ガスの吹込み量が６００Ｎｍ３／ｔ程度で炭素消費原単位の削減効果は飽和する。吹込み温度が３５０℃超６００℃以下となる場合、ボッシュガスの顕熱がより大きい。したがって、水素還元反応による吸熱の影響が小さくなるので、水素ガスを上記の場合よりも多く吹き込んでも、炉内温度が下がりにくくなると考えられる。したがって、多くの水素ガスを高炉内に吹き込んでも炉内温度が下がりにくくなり、ひいては還元効率が下がりにくくなると考えられる。このため、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが飽和すると考えられる。さらに、高濃度水素含有ガス中の水素ガスの吹込み量が３００～６００Ｎｍ３／ｔとなる場合に炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが１０％以上となる。 The reason why the reduction rate Input ΔC of the carbon consumption intensity starts to decrease when the blowing temperature of the high-concentration hydrogen-containing gas is 350 ° C. is the same as the above. When the blowing temperature of the high-concentration hydrogen-containing gas is 600 ° C., the reduction rate Input ΔC of the carbon consumption intensity does not turn to decrease in the range of the blowing amount up to 700 Nm 3 / t. However, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is about 600 Nm 3 / t, the effect of reducing the carbon consumption intensity is saturated. When the blowing temperature is more than 350 ° C and 600 ° C or less, the sensible heat of Bosch gas is larger. Therefore, since the influence of endothermic heat due to the hydrogen reduction reaction is reduced, it is considered that the temperature inside the furnace is unlikely to drop even if more hydrogen gas is blown than in the above case. Therefore, even if a large amount of hydrogen gas is blown into the blast furnace, it is considered that the temperature inside the furnace is difficult to decrease, and thus the reduction efficiency is difficult to decrease. Therefore, it is considered that the reduction rate Input ΔC of the carbon consumption intensity is saturated. Further, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 300 to 600 Nm 3 / t, the reduction rate of carbon consumption intensity is 10% or more.
　図６及び図７に示すように、吹込み温度が６００℃超９００℃以下となる場合にも、高濃度水素含有ガス中の水素ガスの吹込み量をベース操業の０Ｎｍ３／ｔから増加させていくと炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが増加する。そして、高濃度水素含有ガス中の水素ガスの吹込み量が１２５Ｎｍ３／ｔ以上の範囲内の値となる場合に、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが７％以上となる。特に、高濃度水素含有ガス中の水素ガスの吹込み量が１８０Ｎｍ３／ｔ以上の範囲内の値となる場合に、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが１０％以上となる。さらに、高濃度水素含有ガス中の水素ガスの吹込み量の増加に伴って炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃの上昇割合（吹き込み量の単位上昇量に対する炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃの上昇量）は減少するものの、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは減少に転じることがない。これは高濃度水素含有ガスの吹き込み温度が６００℃以下となる場合と明らかに異なる挙動である。なお、図７は高濃度水素含有ガス（ここでは純水素ガス）の吹込み温度が９００℃となる場合の高濃度水素含有ガス中の水素ガスの吹き込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を示すグラフであるが、高濃度水素含有ガスの吹き込み温度が６５０℃となる場合にも図７と同様の傾向がみられた。例えば、図６に示すように、高濃度水素含有ガスの吹込み温度が６５０℃となり、かつ高濃度水素含有ガスの吹込み量が１２５Ｎｍ３／ｔ以上となる場合、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは７．０％以上となった。 As shown in FIGS. 6 and 7, even when the blowing temperature is more than 600 ° C and 900 ° C or lower, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is increased from 0 Nm 3 / t in the base operation. As a result, the reduction rate of carbon consumption intensity, Input ΔC, will increase. When the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is within the range of 125 Nm 3 / t or more, the reduction rate of carbon consumption intensity is 7% or more. In particular, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is within the range of 180 Nm 3 / t or more, the reduction rate of carbon consumption intensity is 10% or more. Furthermore, as the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas increases, the reduction rate of carbon consumption intensity Output △ C increase rate (reduction rate of carbon consumption intensity to the unit increase amount of injection amount Input △ Although the amount of increase in C) decreases, the reduction rate of carbon consumption intensity Input ΔC does not start to decrease. This behavior is clearly different from the case where the blowing temperature of the high-concentration hydrogen-containing gas is 600 ° C. or lower. In addition, FIG. 7 shows the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas and the reduction rate of the carbon consumption intensity when the blowing temperature of the high-concentration hydrogen-containing gas (here, pure hydrogen gas) is 900 ° C. Although it is a graph showing the correlation with C, the same tendency as in FIG. 7 was observed when the blowing temperature of the high-concentration hydrogen-containing gas was 650 ° C. For example, as shown in FIG. 6, when the blowing temperature of the high-concentration hydrogen-containing gas is 650 ° C. and the blowing amount of the high-concentration hydrogen-containing gas is 125 Nm 3 / t or more, the reduction rate of the carbon consumption intensity is Input ΔC was 7.0% or more.
　上述したように、水素ガスによる還元反応は吸熱反応であるため、高濃度水素含有ガス中の水素ガスの吹込み量がある程度増加すると炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが減少に転じる。しかし、高濃度水素含有ガスの吹込み温度が６００℃超であれば、高炉内で生じたボッシュガスの顕熱が非常に高くなるので、還元反応に要する反応熱を賄うことができる。このため、高濃度水素含有ガス中の水素ガスの吹込み量が上昇しても炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは減少に転じず、継続して増加すると考えられる。このような挙動は高濃度水素含有ガスの吹込み温度が６００℃超となる場合に観測される。したがって、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃをより高めるという観点からは、高濃度水素含有ガス中の水素ガスの吹込み量の上限値は特に設定されない。ただし、高濃度水素含有ガス中の水素ガスの吹込み量の増加に伴って炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃの上昇割合が減少することから、ある程度の吹き込み量で炭素消費原単位の削減効果が頭打ちになると想定される。この際の吹き込み量は概ね１０００Ｎｍ３／ｔであると想定される。したがって、高濃度水素含有ガス中の水素ガスの吹込み量は１０００Ｎｍ３／ｔ以下であってもよい。 As described above, since the reduction reaction with hydrogen gas is an endothermic reaction, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas increases to some extent, the reduction rate of carbon consumption intensity Input ΔC starts to decrease. However, if the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C., the sensible heat of the Bosch gas generated in the blast furnace becomes very high, so that the reaction heat required for the reduction reaction can be covered. Therefore, even if the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas increases, the reduction rate of carbon consumption intensity Input ΔC does not start to decrease, but is considered to continue to increase. Such behavior is observed when the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C. Therefore, from the viewpoint of further increasing the reduction rate Input ΔC of the carbon consumption intensity, the upper limit of the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is not particularly set. However, as the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas increases, the rate of decrease in carbon consumption intensity decreases, and the rate of increase in Input △ C decreases. The effect is expected to level off. The amount of blown water at this time is assumed to be approximately 1000 Nm 3 / t. Therefore, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas may be 1000 Nm 3 / t or less.
　図８及び図９に示すように、吹込み温度が９００℃超１２００℃以下となる場合にも、高濃度水素含有ガス中の水素ガスの吹込み量をベース操業の０Ｎｍ３／ｔから増加させていくと炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが増加する。そして、高濃度水素含有ガス中の水素ガスの吹込み量が１１０Ｎｍ３／ｔ以上の範囲内の値となる場合に、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが７％以上となる。特に、高濃度水素含有ガス中の水素ガスの吹込み量が１５０Ｎｍ３／ｔ以上の範囲内の値となる場合に、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが１０％以上となる。さらに、高濃度水素含有ガスの吹込み温度が６００℃超９００℃以下となる場合と同様に、高濃度水素含有ガス中の水素ガスの吹込み量の増加に伴って炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃの上昇割合は減少するものの、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは減少に転じることがない。なお、図９は高濃度水素含有ガス（ここでは純水素ガス）の吹込み温度が１２００℃となる場合の高濃度水素含有ガス中の水素ガスの吹き込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を示すグラフであるが、高濃度水素含有ガスの吹き込み温度が９５０℃となる場合にも図９と同様の傾向がみられた。例えば、図８に示すように、高濃度水素含有ガスの吹込み温度が９５０℃となり、かつ高濃度水素含有ガスの吹込み量が１１０Ｎｍ３／ｔ以上となる場合、炭素消費原単位削減割合Ｉｎｐｕｔ　△Ｃは７．０％以上となった。 As shown in FIGS. 8 and 9, even when the blowing temperature is more than 900 ° C and 1200 ° C or less, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is increased from 0 Nm 3 / t in the base operation. As a result, the reduction rate of carbon consumption intensity, Output ΔC, increases. When the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is within the range of 110 Nm 3 / t or more, the reduction rate of carbon consumption intensity is 7% or more. In particular, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is within the range of 150 Nm 3 / t or more, the reduction rate of carbon consumption intensity is 10% or more. Further, as in the case where the blowing temperature of the high-concentration hydrogen-containing gas becomes more than 600 ° C and 900 ° C or lower, the reduction rate of the carbon consumption intensity as the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas increases. Although the rate of increase in Input ΔC decreases, the rate of decrease in carbon consumption intensity Input ΔC does not turn to decrease. In addition, FIG. 9 shows the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas and the reduction rate of the carbon consumption intensity when the blowing temperature of the high-concentration hydrogen-containing gas (here, pure hydrogen gas) is 1200 ° C. Although it is a graph showing the correlation with C, the same tendency as in FIG. 9 was observed when the blowing temperature of the high-concentration hydrogen-containing gas was 950 ° C. For example, as shown in FIG. 8, when the blowing temperature of the high-concentration hydrogen-containing gas is 950 ° C. and the blowing amount of the high-concentration hydrogen-containing gas is 110 Nm 3 / t or more, the carbon consumption intensity reduction rate Input ΔC was 7.0% or more.
　したがって、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃをより高めるという観点からは、高濃度水素含有ガス中の水素ガスの吹込み量の上限値は特に設定されない。ただし、高濃度水素含有ガス中の水素ガスの吹込み量が１０００Ｎｍ３／ｔ程度となる場合に炭素消費原単位の削減効果が頭打ちになると想定されることから、高濃度水素含有ガス中の水素ガスの吹込み量は１０００Ｎｍ３／ｔ以下であってもよい。 Therefore, from the viewpoint of further increasing the reduction rate Input ΔC of the carbon consumption intensity, the upper limit of the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is not particularly set. However, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas reaches about 1000 Nm 3 / t, the effect of reducing the carbon consumption intensity is expected to peak, so hydrogen in the high-concentration hydrogen-containing gas The amount of gas blown may be 1000 Nm 3 / t or less.
　なお、高炉操業シミュレーションによれば、高濃度水素含有ガスの吹込み温度が１２００℃となり、かつ高濃度水素含有ガス中の水素ガスの吹込み量が８００Ｎｍ３／ｔ以上となる場合、微粉炭吹込み量が０となり、コークス比を低減することで更なる炭素消費原単位の削減が可能となった。一般に、高炉操業においては、コークス比の低減は圧力損失の上昇を招き、操業不安定となる。ここで、圧力損失は、羽口先（羽口前）での圧力、言い換えると羽口の出口における炉内圧力と炉頂での圧力との差であり、送風機から羽口先への配管圧損を除いた値をいう。実際の操業では、圧力損失は炉壁部に設置された圧力計によって測定される。しかし、図１４に示すように、本実施形態のような高水素濃度条件での高炉操業においては、炉内ガス粘度、ガス密度が大きく低下するため、コークス比を低減させた際の圧力損失の上昇の懸念は解消され、実操業において安定した操業に問題ない程度の圧損である。なお、図１４は、羽口前温度が２１００℃となる際の、１２００℃の純水素ガスの吹込み量と炉内圧力損失の変化量との相関を示すグラフであり、高炉操業シミュレーションにより得られるものである。通常操業における圧力損失は概ね８５ｋＰａ程度が目安となっている。図１４によれば、本実施形態の操業条件では、圧力損失が８５ｋＰａ未満となっていることがわかる。 According to the blast furnace operation simulation, when the blowing temperature of the high-concentration hydrogen-containing gas is 1200 ° C. and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 800 Nm 3 / t or more, pulverized coal blowing The amount of inclusion became 0, and by reducing the coke ratio, it became possible to further reduce the carbon consumption intensity. Generally, in blast furnace operation, a decrease in coke ratio causes an increase in pressure loss, resulting in unstable operation. Here, the pressure loss is the difference between the pressure at the tuyere tip (in front of the tuyere), in other words, the pressure inside the furnace at the outlet of the tuyere and the pressure at the top of the furnace, excluding the pipe pressure loss from the blower to the tuyere tip. Value. In actual operation, the pressure loss is measured by a pressure gauge installed on the furnace wall. However, as shown in FIG. 14, in the blast furnace operation under the high hydrogen concentration condition as in the present embodiment, the gas viscosity and the gas density in the furnace are significantly lowered, so that the pressure loss when the coke ratio is reduced is increased. Concerns about the rise have been resolved, and the pressure loss is such that there is no problem with stable operations in actual operations. FIG. 14 is a graph showing the correlation between the amount of pure hydrogen gas blown at 1200 ° C. and the amount of change in the pressure loss in the furnace when the temperature in front of the tuyere reaches 2100 ° C., which was obtained by blast furnace operation simulation. It is something that can be done. The pressure loss in normal operation is about 85 kPa as a guide. According to FIG. 14, it can be seen that the pressure loss is less than 85 kPa under the operating conditions of the present embodiment.
　図１０に示すように、吹込み温度が１２００℃超となる場合にも、高濃度水素含有ガス中の水素ガスの吹込み量をベース操業の０Ｎｍ３／ｔから増加させていくと炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが増加する。そして、高濃度水素含有ガス中の水素ガスの吹込み量が１００Ｎｍ３／ｔ以上の範囲内の値となる場合に、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが７％以上となる。さらに、高濃度水素含有ガスの吹込み温度が６００℃超９００℃以下となる場合と同様に、高濃度水素含有ガス中の水素ガスの吹込み量の増加に伴って炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃの上昇割合は減少するものの、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは減少に転じることがない。したがって、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃをより高めるという観点からは、高濃度水素含有ガス中の水素ガスの吹込み量の上限値は特に設定されない。ただし、高濃度水素含有ガス中の水素ガスの吹込み量が１０００Ｎｍ３／ｔ程度となる場合に炭素消費原単位の削減効果が頭打ちになると想定されることから、高濃度水素含有ガス中の水素ガスの吹込み量は１０００Ｎｍ３／ｔ以下であってもよい。 As shown in FIG. 10, even when the blowing temperature exceeds 1200 ° C., if the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is increased from 0 Nm 3 / t in the base operation, the carbon consumption source is increased. Unit reduction rate Input ΔC increases. When the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is within the range of 100 Nm 3 / t or more, the reduction rate of carbon consumption intensity is 7% or more. Further, as in the case where the blowing temperature of the high-concentration hydrogen-containing gas becomes more than 600 ° C and 900 ° C or lower, the reduction rate of the carbon consumption intensity as the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas increases. Although the rate of increase in Input ΔC decreases, the rate of decrease in carbon consumption intensity Input ΔC does not turn to decrease. Therefore, from the viewpoint of further increasing the reduction rate Input ΔC of the carbon consumption intensity, the upper limit of the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is not particularly set. However, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas reaches about 1000 Nm 3 / t, the effect of reducing the carbon consumption intensity is expected to peak, so hydrogen in the high-concentration hydrogen-containing gas The amount of gas blown may be 1000 Nm 3 / t or less.
　高濃度水素含有ガスの吹込み温度を６００℃超にできる環境であれば、吹込み温度の上限値は特に制限されない。ただし、図１５及び図１６に示されるように、炭素消費原単位の削減効果は、高濃度水素含有ガスの吹込み温度が１２００℃超から１４００℃程度の範囲でほぼ横ばいになる。なお、図１５及び図１６は、純水素ガスの吹込み温度と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを１０％または２０％とするために必要な純水素ガスの吹込み量との相関を示すグラフである。羽口前温度Ｔｆは２１００℃とした。これらのグラフは図２～図１０の相関を純水素ガスの吹込み温度と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを１０％または２０％とするために必要な純水素ガスの吹込み量との相関に整理したものである。したがって、高濃度水素含有ガスの吹込み温度は１４００℃以下であってもよい。すなわち、高濃度水素含有ガスの吹込み温度は、例えば６００℃超１４００℃以下であってもよい。 The upper limit of the blowing temperature is not particularly limited as long as the blowing temperature of the high-concentration hydrogen-containing gas can exceed 600 ° C. However, as shown in FIGS. 15 and 16, the effect of reducing the carbon consumption intensity is almost flat in the range where the blowing temperature of the high-concentration hydrogen-containing gas is in the range of more than 1200 ° C to about 1400 ° C. In addition, FIG. 15 and FIG. 16 show the correlation between the blowing temperature of pure hydrogen gas and the blowing amount of pure hydrogen gas required to set the carbon consumption intensity reduction rate Input ΔC to 10% or 20%. It is a graph which shows. The tuyere front temperature Tf was 2100 ° C. These graphs show the correlation between FIGS. 2 to 10 with the amount of pure hydrogen gas blown in to make the pure hydrogen gas blowing temperature and the reduction rate of carbon consumption intensity Input ΔC 10% or 20%. It is organized in the correlation of. Therefore, the blowing temperature of the high-concentration hydrogen-containing gas may be 1400 ° C. or lower. That is, the blowing temperature of the high-concentration hydrogen-containing gas may be, for example, more than 600 ° C. and 1400 ° C. or lower.
　ついで、高濃度水素含有ガスを決定された吹込み温度及び吹込み量で羽口から吹き込む。これにより、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを例えば７％以上とすることができ、ひいては、ＣＯ２排出量を大きく削減することができる。なお、高濃度水素含有ガスを吹き込む羽口は、例えば炉下部に設けられた熱風吹込み用の羽口である。本実施形態では、高濃度水素含有ガスを熱風吹込み用の羽口から吹き込むことを前提として説明を行うが、高濃度水素含有ガスを吹き込む羽口はこれに限定されない。羽口の他の例としては、シャフト部に設けられた所謂シャフト羽口が挙げられる。高濃度水素含有ガスは、これらの羽口の何れかから高炉内に吹き込まれてもよいし、両方の羽口から高炉内に吹き込まれてもよい。複数の羽口から高濃度水素含有ガスを高炉内に吹き込む場合、各羽口から吹き込まれる高濃度水素含有ガス中の水素ガスの吹込み量の総和が上記決定された吹込み量に一致する。 Then, the high-concentration hydrogen-containing gas is blown from the tuyere at the determined blowing temperature and blowing amount. As a result, the reduction rate of carbon consumption intensity can be set to 7% or more, and CO 2 emissions can be significantly reduced. The tuyere for blowing the high-concentration hydrogen-containing gas is, for example, a tuyere for blowing hot air provided in the lower part of the furnace. In the present embodiment, the description will be made on the premise that the high-concentration hydrogen-containing gas is blown from the tuyere for blowing hot air, but the tuyere for blowing the high-concentration hydrogen-containing gas is not limited to this. Another example of the tuyere is a so-called shaft tuyere provided on the shaft portion. The high-concentration hydrogen-containing gas may be blown into the blast furnace from any of these tuyere, or may be blown into the blast furnace from both tuyere. When high-concentration hydrogen-containing gas is blown into the blast furnace from a plurality of tuyere, the total amount of hydrogen gas blown into the high-concentration hydrogen-containing gas blown from each tuyere matches the above-determined blowing amount.
　なお、本実施形態の条件下で適切に水素ガスの吹込み温度、吹込み量、羽口前温度Ｔｆ等を設定することにより、炉頂ガス温度を適切に維持する操業が可能となる。このため、炉頂ガス温度の維持のために行われる予熱ガス吹込みや炉内装入物の予熱は不要になるが、別途それらを実施しても良い。 By appropriately setting the hydrogen gas blowing temperature, blowing amount, tuyere front temperature Tf, etc. under the conditions of the present embodiment, it is possible to operate to maintain the furnace top gas temperature appropriately. For this reason, it is not necessary to blow in the preheating gas or preheat the contents inside the furnace to maintain the temperature of the furnace top gas, but these may be performed separately.
　＜４．変形例＞
　（４－１．変形例１）
　以下、高炉の操業方法の各種変形例を説明する。変形例１では、羽口前温度Ｔｆを２０５０℃以下に維持する。ここで、羽口前温度Ｔｆは、羽口の炉内側先端部における炉内温度であり、羽口先温度Ｔｆとも称される。実際の操業では、羽口前温度Ｔｆは、重見彰利著「製銑ハンドブック」（地人書館）に記載されたラムの式に従って羽口先理論燃焼温度として算出される。 <4. Modification example>
(4-1. Modification 1)
Hereinafter, various modifications of the operating method of the blast furnace will be described. In the first modification, the tuyere front temperature Tf is maintained at 2050 ° C. or lower. Here, the tuyere front temperature Tf is the furnace temperature at the tip of the tuyere inside the furnace, and is also referred to as the tuyere tip temperature Tf. In actual operation, the tuyere temperature Tf is calculated as the tuyere tip theoretical combustion temperature according to the Lamb's formula described in the "Pig Iron Handbook" (Chijin Shokan) by Akitoshi Shigemi.
　図２、図３、図５、図７、及び図９に示されるように、羽口前温度Ｔｆが２０５０℃以下（図２、図３、図５、図７、及び図９では２０００℃）となる場合の炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは、羽口前温度Ｔｆが２０５０℃超となる場合（図２、図３、図５、図７、及び図９では２１００℃、２２００℃）の炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃよりも大きくなる。そこで、変形例１では、羽口前温度Ｔｆを２０５０℃以下に維持する。これにより、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃをより大きくすることができる。なお、図７及び図９に示される通り、高濃度水素含有ガスの吹込み温度が６００℃超となる場合、高濃度水素含有ガス中の水素ガスの吹き込み量が４００Ｎｍ３／ｔ以上となる場合に、この傾向が顕著に現れる。したがって、高濃度水素含有ガスの吹込み温度を６００℃超とし、さらに高濃度水素含有ガス中の水素ガスの吹き込み量を４００Ｎｍ３／ｔ以上とする場合に、羽口前温度Ｔｆを２０５０℃以下としてもよい。 As shown in FIGS. 2, 3, 5, 7, and 9, the tuyere temperature Tf is 2050 ° C. or lower (2000 ° C. in FIGS. 2, 3, 5, 7, and 9). The reduction rate of carbon consumption intensity in the case of Input ΔC is 2100 ° C. and 2200 ° C. in FIGS. 2, FIG. 3, FIG. 5, FIG. 7, and FIG. 9 when the tuyere temperature Tf exceeds 2050 ° C. ) Reduction rate of carbon consumption intensity is larger than Input ΔC. Therefore, in the first modification, the tuyere front temperature Tf is maintained at 2050 ° C. or lower. As a result, the reduction rate Input ΔC of the carbon consumption intensity can be further increased. As shown in FIGS. 7 and 9, when the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C., the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 400 Nm 3 / t or more. In addition, this tendency is remarkable. Therefore, when the blowing temperature of the high-concentration hydrogen-containing gas is more than 600 ° C. and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 400 Nm 3 / t or more, the tuyere temperature Tf is 2050 ° C. or less. May be.
　ここで、高濃度水素含有ガスの吹込み温度は熱風よりも低いので、高濃度水素含有ガスを高炉内に吹き込むことによって羽口前温度Ｔｆが低下する。羽口前温度Ｔｆを所望の温度とするためには、すなわち、羽口前温度Ｔｆを高めるためには、酸素富化率を上げて操業を行う必要がある。ここで、高炉に吹き込まれる熱風は空気を含むガスである。熱風には、空気の他に湿分及び富化酸素をさらに含んでいても良い。酸素富化率とは、概略的には、熱風の総体積に対する熱風中の酸素の体積割合であり、酸素富化率（％）＝｛（空気の送風量（流量）［Ｎｍ３／ｍｉｎ］×０．２１＋酸素富化量［Ｎｍ３／ｍｉｎ］）／（空気の送風量［Ｎｍ３／ｍｉｎ］＋酸素富化量［Ｎｍ３／ｍｉｎ］）｝×１００－２１であらわされる。実際の操業では、単位Ｎｍ３／ｔでの富化酸素と熱風中の酸素との合計流量である酸素の流量は変えずに、単位Ｎｍ３／ｔでの富化酸素の流量と空気の流量を変えることで酸素富化率を調整する。出銑比（炉内容積１ｍ３あたりの１日の出銑量）をなるべく一定とするためである。したがって、酸素富化率が高くなると、熱風の流量が減少する。この結果、ボッシュガス量が減少する。 Here, since the blowing temperature of the high-concentration hydrogen-containing gas is lower than that of the hot air, the tuyere temperature Tf is lowered by blowing the high-concentration hydrogen-containing gas into the blast furnace. In order to set the tuyere temperature Tf to a desired temperature, that is, to raise the tuyere temperature Tf, it is necessary to increase the oxygen enrichment rate and perform the operation. Here, the hot air blown into the blast furnace is a gas containing air. The hot air may further contain moisture and enriched oxygen in addition to air. The oxygen enrichment rate is roughly the volume ratio of oxygen in the hot air to the total volume of the hot air, and the oxygen enrichment rate (%) = {(air flow rate (flow rate) [Nm 3 / min]]. It is represented by × 0.21 + oxygen enrichment amount [Nm 3 / min]) / (air ventilation amount [Nm 3 / min] + oxygen enrichment amount [Nm 3 / min])} × 100-21. In actual operation, without changing the flow rate of oxygen which is total flow rate of enriched oxygen and oxygen in the hot air in the unit Nm 3 / t, of enriched oxygen in units Nm 3 / t flow rate and air flow rate Adjust the oxygen enrichment rate by changing. This is to keep the pig iron output ratio (the amount of pig iron per sunrise per 1 m 3 of the furnace volume) as constant as possible. Therefore, as the oxygen enrichment rate increases, the flow rate of hot air decreases. As a result, the amount of Bosch gas is reduced.
　したがって、羽口前温度Ｔｆが高いほど、ボッシュガス量が減少する。そして、ボッシュガス量が減少すると、ボッシュガスの顕熱が減少する。したがって、水素還元反応による吸熱により炉内温度が低下しやすくなる。そして、このような炉内温度の低下を防止するためには、還元材比を高めた操業を行う必要がある。このため、羽口前温度Ｔｆが２０５０℃以下となる場合の炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは、羽口前温度Ｔｆが２０５０℃超となる場合の炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃよりも大きくなると考えられる。 Therefore, the higher the tuyere temperature Tf, the smaller the amount of Bosch gas. Then, when the amount of Bosch gas decreases, the sensible heat of Bosch gas decreases. Therefore, the temperature inside the furnace tends to decrease due to the endothermic heat generated by the hydrogen reduction reaction. Then, in order to prevent such a decrease in the temperature inside the furnace, it is necessary to carry out an operation in which the ratio of the reducing agent is increased. Therefore, the reduction rate of carbon consumption intensity when the tuyere temperature Tf is 2050 ° C. or less Input ΔC is the reduction rate of carbon consumption intensity when the tuyere temperature Tf is over 2050 ° C. Input ΔC. It is considered to be larger than C.
　なお、溶銑への着熱及び微粉炭燃焼性の観点からは、羽口前温度Ｔｆは２０００℃以上であることが好ましい。ただし、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが十分大きくなり、微粉炭比（溶銑１トンあたりに使用する微粉炭）が十分に低くできるのであれば、羽口前温度Ｔｆは２０００℃未満であってもよい。例えば、羽口前温度Ｔｆを２０００℃未満としても炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを維持でき、かつ安定した操業が可能であれば、羽口前温度Ｔｆを２０００℃未満としてもよい。この点、例えば、上述したように、高濃度水素含有ガスの吹込み温度が１２００℃となり、かつ高濃度水素含有ガス中の水素ガスの吹込み量が８００Ｎｍ３／ｔ以上となる場合、微粉炭吹込み量が０（すなわち、微粉炭比が０）となる。この場合、微粉炭の燃焼を考慮する必要がないので、羽口前温度Ｔｆを２０００℃未満としても炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを維持でき、かつ安定した操業が可能となる。したがって、羽口前温度Ｔｆを２０００℃未満とすることができる。つまり、高濃度水素含有ガスの吹込み温度を高め、かつ吹き込み量を多くした結果、微粉炭吹込み量を０とすることができれば、羽口前温度Ｔｆを２０００℃未満としてもよい。 From the viewpoint of heat transfer to the hot metal and flammability of pulverized coal, the tuyere temperature Tf is preferably 2000 ° C. or higher. However, if the reduction rate Input ΔC of the carbon consumption intensity is sufficiently large and the pulverized coal ratio (the pulverized coal used per ton of hot metal) can be sufficiently lowered, the tuyere temperature Tf is less than 2000 ° C. There may be. For example, even if the tuyere temperature Tf is less than 2000 ° C., the tuyere temperature Tf may be less than 2000 ° C. as long as the reduction rate Input ΔC of the carbon consumption intensity can be maintained and stable operation is possible. In this respect, for example, as described above, when the blowing temperature of the high-concentration hydrogen-containing gas is 1200 ° C. and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 800 Nm 3 / t or more, pulverized coal. The blowing amount is 0 (that is, the pulverized coal ratio is 0). In this case, since it is not necessary to consider the combustion of pulverized coal, the reduction rate Input ΔC of the carbon consumption intensity can be maintained even if the tuyere temperature Tf is less than 2000 ° C., and stable operation becomes possible. Therefore, the tuyere front temperature Tf can be set to less than 2000 ° C. That is, as a result of raising the blowing temperature of the high-concentration hydrogen-containing gas and increasing the blowing amount, if the pulverized coal blowing amount can be set to 0, the tuyere front temperature Tf may be set to less than 2000 ° C.
　（４－２．変形例２）
　変形例２では、羽口前温度Ｔｆを２０５０℃超２１５０℃以下に維持する。変形例１によれば、羽口前温度Ｔｆを２０５０℃以下とすることで炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを大きくすることができる。一方で、羽口前温度Ｔｆが低下すると、微粉炭の燃焼率が低下する可能性がある。つまり、羽口前温度Ｔｆが低下すると、微粉炭が燃焼しにくくなる。微粉炭が難燃性である場合や、微粉炭比を高めて操業を行う場合、微粉炭の燃焼率が低下する可能性がより高まる。微粉炭の燃焼率が低下すると、炉内温度が低下するので、その分だけ還元材比を高めた操業を行う必要が生じうる。このような観点から、変形例２では、羽口前温度Ｔｆを２０５０℃超２１５０℃以下に維持する。これにより、微粉炭の燃焼率を維持し、ひいては、炉内温度の低下を抑制することができる。 (4-2. Modification 2)
In the second modification, the tuyere front temperature Tf is maintained above 2050 ° C. and below 2150 ° C. According to the first modification, the reduction rate Input ΔC of the carbon consumption intensity can be increased by setting the tuyere front temperature Tf to 2050 ° C. or lower. On the other hand, when the tuyere temperature Tf decreases, the combustion rate of pulverized coal may decrease. That is, when the tuyere temperature Tf decreases, it becomes difficult for the pulverized coal to burn. When the pulverized coal is flame-retardant or when the operation is performed with a high pulverized coal ratio, the possibility that the combustion rate of the pulverized coal decreases is further increased. When the combustion rate of pulverized coal decreases, the temperature inside the furnace decreases, so that it may be necessary to carry out an operation in which the ratio of the reducing agent is increased accordingly. From this point of view, in the modified example 2, the tuyere front temperature Tf is maintained above 2050 ° C and below 2150 ° C. As a result, the combustion rate of the pulverized coal can be maintained, and thus the decrease in the temperature inside the furnace can be suppressed.
　（４－３．変形例３）
　変形例３では、羽口前温度Ｔｆを２１５０℃超に維持する。従来の高炉操業では、羽口前温度Ｔｆは２２００℃程度とされることが多い。したがって、羽口前温度Ｔｆを２１５０℃超とすることで、従来の高炉操業と大きく操業条件を変えずに操業を行うことができる。なお、羽口設備保護等の観点から、羽口前温度Ｔｆは２２５０℃以下が好ましい。 (4-3. Modification 3)
In the third modification, the tuyere front temperature Tf is maintained above 2150 ° C. In conventional blast furnace operation, the tuyere temperature Tf is often set to about 2200 ° C. Therefore, by setting the tuyere front temperature Tf to more than 2150 ° C., the operation can be performed without significantly changing the operating conditions from the conventional blast furnace operation. From the viewpoint of protecting the tuyere equipment, the tuyere front temperature Tf is preferably 2250 ° C. or lower.
　（４－４．変形例４）
　図２～図１０に示されるように、高濃度水素含有ガス中の水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの間には一定の相関がある。そこで、変形例４では、高濃度水素含有ガス中の水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関である吹込み量－炭素消費原単位削減割合相関を予め求める。 (4-4. Modification 4)
As shown in FIGS. 2 to 10, there is a certain correlation between the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas and the reduction rate of carbon consumption intensity Input ΔC. Therefore, in the modified example 4, the injection amount-carbon consumption intensity reduction ratio correlation, which is the correlation between the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas and the carbon consumption intensity reduction rate Input ΔC, is obtained in advance. ..
　例えば、高濃度水素含有ガスの吹込み温度を含む現状の高炉操業を反映した高炉操業シミュレーションにより何点かの吹込み量のそれぞれに対する炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを求める。具体的な方法は後述する実施例と同様の方法であればよい。 For example, the reduction ratio of carbon consumption intensity to each of several blown amounts is calculated by the blast furnace operation simulation that reflects the current blast furnace operation including the blowing temperature of the high-concentration hydrogen-containing gas. The specific method may be the same as that of the examples described later.
　ついで、横軸を単位Ｎｍ３／ｔでの高濃度水素含有ガス中の水素ガスの吹込み量、縦軸を炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃ（％）とした平面上に上記方法で求めた値をプロットする。ついで、これらのプロットの近似曲線を例えば最小二乗法で求め、この近似曲線、より具体的には、近似曲線を示す関係式を上述した吹込み量－炭素消費原単位削減割合相関とすればよい。吹込み量－炭素消費原単位削減割合相関は、羽口前温度Ｔｆ毎に求めることが好ましい。 Then, the horizontal axis is the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas in the unit Nm 3 / t, and the vertical axis is the reduction rate of carbon consumption intensity Input ΔC (%). Plot the calculated value. Then, the approximate curves of these plots may be obtained by, for example, the least squares method, and the relational expression showing the approximate curves, more specifically, the approximate curves may be used as the above-mentioned injection amount-carbon consumption intensity reduction ratio correlation. .. The correlation between the amount of blown material and the reduction rate of carbon consumption intensity is preferably obtained for each tuyere temperature Tf.
　ついで、現状の操業よりも炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが大きくなる吹込み量、すなわち、炭素消費量が低減する吹込み量を上記で求めた吹込み量－炭素消費原単位削減割合相関に基づいて決定する。ついで、高濃度水素含有ガスを当該決定された吹込み量で羽口から吹き込む。これにより、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃをより確実に大きくすることができる。 Next, the reduction rate of carbon consumption intensity is larger than that of the current operation. Input ΔC is larger. That is, the injection amount for which carbon consumption is reduced is calculated above. Determined based on correlation. Then, a high-concentration hydrogen-containing gas is blown from the tuyere at the determined blowing amount. As a result, the reduction rate Input ΔC of the carbon consumption intensity can be increased more reliably.
　ここで、吹込み量－炭素消費原単位削減割合相関は、高濃度水素含有ガスの吹込み温度毎に予め求めておくことが好ましい。これにより、吹込み温度が変動した場合にも容易に所望の高濃度水素含有ガス中の水素ガスの吹込み量を決定することができる。すなわち、吹込み温度が変動した場合にも、容易に炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが大きくなる高濃度水素含有ガス中の水素ガスの吹込み量を決定することができる。 Here, it is preferable to obtain the correlation between the blown amount and the carbon consumption intensity reduction ratio for each blown temperature of the high-concentration hydrogen-containing gas in advance. Thereby, even when the blowing temperature fluctuates, the amount of hydrogen gas blown into the desired high-concentration hydrogen-containing gas can be easily determined. That is, even when the blowing temperature fluctuates, it is possible to easily determine the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas in which the reduction rate Input ΔC of the carbon consumption intensity becomes large.
　（４－５．変形例５）
　図１２は、単位Ｎｍ３／ｔでの常温の純水素ガスの吹込み量と高濃度水素含有ガスを吹き込まない操業であるベース操業に対する単位ｋＰａでの圧力損失の変化量との相関を羽口前温度Ｔｆ毎に示すグラフである。このグラフは高炉操業シミュレーションによって得られるものである。詳細は実施例で説明する。ここで、圧力損失は、羽口先（羽口前）での圧力、言い換えると羽口の出口における炉内圧力と炉頂での圧力との差であり、送風機から羽口先への配管圧損を除いた値をいう。実際の操業では、圧力損失は炉壁部に設置された圧力計によって測定される。ベース操業に対する圧力損失の変化量は、ある操業時の圧力損失からベース操業時の圧力損失を減算した値である。圧力損失は、送風圧力の制約や吹き抜け防止等の観点からベース操業と同程度、あるいはベース操業より低い値となることが好ましい。図１２は常温の純水素ガスを用いた場合の上記相関を示すが、純水素ガス以外の高濃度水素含有ガスを用いた場合にも上記相関が得られる。また、高濃度水素含有ガスの吹込み温度が常温より大きくても上記相関が得られる。 (4-5. Modification 5)
FIG. 12 shows the correlation between the amount of pure hydrogen gas blown at room temperature in the unit Nm 3 / t and the amount of change in pressure loss in the unit kPa with respect to the base operation, which is an operation in which high-concentration hydrogen-containing gas is not blown. It is a graph which shows for each pre-temperature Tf. This graph is obtained by blast furnace operation simulation. Details will be described in Examples. Here, the pressure loss is the difference between the pressure at the tuyere tip (in front of the tuyere), in other words, the pressure inside the furnace at the outlet of the tuyere and the pressure at the top of the furnace, excluding the pipe pressure loss from the blower to the tuyere tip. Value. In actual operation, the pressure loss is measured by a pressure gauge installed on the furnace wall. The amount of change in pressure loss with respect to the base operation is the value obtained by subtracting the pressure loss during the base operation from the pressure loss during a certain operation. It is preferable that the pressure loss is about the same as that of the base operation or lower than that of the base operation from the viewpoint of restricting the blowing pressure and preventing blow-by. FIG. 12 shows the above correlation when pure hydrogen gas at room temperature is used, but the above correlation can also be obtained when a high-concentration hydrogen-containing gas other than pure hydrogen gas is used. Further, the above correlation can be obtained even if the blowing temperature of the high-concentration hydrogen-containing gas is higher than room temperature.
　図１２から明らかな通り、高濃度水素含有ガス中の水素ガスの吹込み量と圧力損失の変化量との間には一定の相関がある。例えば、高濃度水素含有ガス中の水素ガスの吹込み量を増加させた場合、上述したように、羽口前温度Ｔｆが低下する。羽口前温度を所望の温度とするためには、酸素富化率を上げて操業を行う必要がある。実際の操業では、単位Ｎｍ３／ｔでの富化酸素と熱風中の酸素との合計流量である酸素の流量は変えずに、単位Ｎｍ３／ｔ富化酸素の流量と空気の流量を変えることで、出銑量を所定量に保ちつつ酸素富化率を調整する。したがって、酸素富化率が高くなると、熱風の流量が減少する。この結果、ボッシュガス量が減少する。言い換えれば、羽口前温度Ｔｆが低い場合、ボッシュガス量が増加する。この結果、ベース操業に比べて圧力損失が大きくなる可能性がある。ただし、高濃度水素含有ガス中の水素ガスの吹込み量がさらに増加すると、炉内ガスのガス粘度及びガス密度が低下し、圧力損失が小さくなる。そして、ガス粘度及びガス密度の低下による圧力損失の減少がボッシュガス量の増加による圧力損失の増加を相殺し、結果として圧力損失が減少する。 As is clear from FIG. 12, there is a certain correlation between the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas and the amount of change in pressure loss. For example, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is increased, the tuyere temperature Tf decreases as described above. In order to obtain the desired temperature before the tuyere, it is necessary to increase the oxygen enrichment rate and perform the operation. In actual operation, without changing the flow rate of oxygen which is total flow rate of enriched oxygen and oxygen in the hot air in the unit Nm 3 / t, varying the flow rate and the flow rate of the air unit Nm 3 / t-enriched oxygen By doing so, the oxygen enrichment rate is adjusted while keeping the amount of tapping at a predetermined amount. Therefore, as the oxygen enrichment rate increases, the flow rate of hot air decreases. As a result, the amount of Bosch gas is reduced. In other words, when the tuyere temperature Tf is low, the amount of Bosch gas increases. As a result, the pressure loss may be larger than that of the base operation. However, if the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is further increased, the gas viscosity and gas density of the gas in the furnace are lowered, and the pressure loss is reduced. Then, the decrease in pressure loss due to the decrease in gas viscosity and gas density offsets the increase in pressure loss due to the increase in the amount of Bosch gas, and as a result, the pressure loss decreases.
　変形例５では、まず、変形例４と同様に吹込み量－炭素消費原単位削減割合相関を予め求める。さらに、吹込み量とベース操業に対する圧力損失の変化量との相関である吹込み量－圧力損失変化量相関を求める。 In the modified example 5, first, the injection amount-carbon consumption intensity reduction ratio correlation is obtained in advance in the same manner as in the modified example 4. Furthermore, the correlation between the amount of blown air and the amount of change in pressure loss, which is the correlation between the amount of blown air and the amount of change in pressure loss with respect to the base operation, is obtained.
　例えば、高濃度水素含有ガスの吹込み温度を含む現状の高炉操業を反映した高炉操業シミュレーションにより何点かの吹込み量のそれぞれに対する圧力損失の変化量を求める。具体的な方法は後述する実施例と同様の方法であればよい。 For example, the amount of change in pressure loss with respect to each of several blowing amounts is obtained by a blast furnace operation simulation that reflects the current blast furnace operation including the blowing temperature of high-concentration hydrogen-containing gas. The specific method may be the same as that of the examples described later.
　ついで、横軸を単位Ｎｍ３／ｔでの高濃度水素含有ガス中の水素ガスの吹込み量、単位ｋＰａでの縦軸を圧力損失の変化量である△圧力損失とした平面上に上記方法で求めた値をプロットする。ついで、これらのプロットの近似曲線を例えば最小二乗法で求め、この近似曲線（より具体的には、近似曲線を示す関係式）を上述した吹込み量－圧力損失変化量相関とすればよい。吹込み量－圧力損失変化量相関は、羽口前温度Ｔｆ毎に求めることが好ましい。 Next, the above method is on a plane in which the horizontal axis is the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas in the unit Nm 3 / t and the vertical axis is the amount of change in the pressure loss in the unit kPa. Plot the value obtained in. Then, the approximate curves of these plots may be obtained by, for example, the least squares method, and this approximate curve (more specifically, the relational expression showing the approximate curve) may be used as the above-mentioned blow amount-pressure loss change amount correlation. The correlation between the amount of blown air and the amount of change in pressure loss is preferably obtained for each tuyere temperature Tf.
　ついで、現状の操業よりも炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが大きくなり、すなわち、炭素消費量が低減し、かつ圧力損失の変化量が所定範囲内の値となる吹込み量を吹込み量－炭素消費原単位削減割合相関及び吹込み量－圧力損失変化量相関に基づいて決定する。ここで、所定範囲は、例えば－５０～＋５ｋＰａ程度とされるが、これに限定されない。ついで、高濃度水素含有ガスを当該決定された吹込み量で羽口から吹き込む。これにより、圧力損失の変化量を所定範囲内の値としつつ、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃをより確実に大きくすることができる。 Next, the reduction rate Input ΔC of the carbon consumption intensity is larger than that of the current operation, that is, the amount of injection is injected so that the amount of carbon consumption is reduced and the amount of change in pressure loss is within a predetermined range. Determined based on the amount-carbon consumption intensity reduction rate correlation and the injection amount-pressure loss change amount correlation. Here, the predetermined range is, for example, about −50 to +5 kPa, but is not limited to this. Then, a high-concentration hydrogen-containing gas is blown from the tuyere at the determined blowing amount. As a result, it is possible to more reliably increase the reduction rate Input ΔC of the carbon consumption intensity while keeping the amount of change in pressure loss within a predetermined range.
　（４－６．変形例６）
　図１３は、常温の単位Ｎｍ３／ｔでの純水素ガスの吹込み量と単位℃でのベース操業に対する炉頂ガス温度の変化量との相関を羽口前温度Ｔｆ毎に示すグラフである。このグラフは高炉操業シミュレーションによって得られるものである。詳細は実施例で説明する。ここで、炉頂ガス温度は、高炉の炉頂から排出される炉頂ガス（主にＣＯ２、Ｎ２、未反応のＣＯ等）の温度であり、実際の操業では、上昇管等に設置された温度計によって測定される。ベース操業に対する炉頂ガス温度の変化量は、ある操業時の炉頂ガス温度からベース操業時の炉頂ガス温度を減算した値である。炉頂ガス温度は、炉頂設備の制約や操業効率化の観点からベース操業と同程度であることが好ましく、一例としてベース操業の炉頂ガス温度±２０℃程度の範囲内であることが好ましい。図１３は常温の純水素ガスを用いた場合の上記相関を示すが、純水素ガス以外の高濃度水素含有ガスを用いた場合にも上記相関が得られる。また、高濃度水素含有ガスの吹込み温度が常温より大きくても上記相関が得られる。 (4-6. Modification 6)
FIG. 13 is a graph showing the correlation between the amount of pure hydrogen gas blown in the unit Nm 3 / t at room temperature and the amount of change in the furnace top gas temperature with respect to the base operation at the unit ° C. for each tuyere temperature Tf. .. This graph is obtained by blast furnace operation simulation. Details will be described in Examples. Here, the furnace top gas temperature is the temperature of the top gas (mainly CO 2 , N 2 , unreacted CO, etc.) discharged from the top of the blast furnace, and is installed in the riser pipe or the like in actual operation. Measured by a thermometer. The amount of change in the top gas temperature with respect to the base operation is a value obtained by subtracting the top gas temperature during the base operation from the top gas temperature during a certain operation. The furnace top gas temperature is preferably about the same as the base operation from the viewpoint of restrictions on the furnace top equipment and operational efficiency, and as an example, the furnace top gas temperature of the base operation is preferably within the range of about ± 20 ° C. .. FIG. 13 shows the above correlation when a pure hydrogen gas at room temperature is used, but the above correlation can also be obtained when a high-concentration hydrogen-containing gas other than the pure hydrogen gas is used. Further, the above correlation can be obtained even if the blowing temperature of the high-concentration hydrogen-containing gas is higher than room temperature.
　図１３から明らかな通り、高濃度水素含有ガス中の水素ガスの吹込み量と炉頂ガス温度の変化量との間には一定の相関がある。例えば、高濃度水素含有ガス中の水素ガスの吹込み量を増加させた場合、上述したように、羽口前温度Ｔｆが低下する。羽口前温度Ｔｆを所望の温度とするためには、酸素富化率を上げて操業を行う必要がある。実際の操業では、単位Ｎｍ３／ｔでの酸素の流量は変えずに単位Ｎｍ３／ｔでの空気の流量を変えることで酸素富化率を調整する。したがって、酸素富化率が高くなると、熱風の流量が減少する。この結果、ボッシュガス量が減少する。言い換えれば、羽口前温度Ｔｆが上昇すると、ボッシュガス量が減少する。このため、（単位時間あたりに下降してくる炉内装入物の熱容量）／（単位時間当たりに上昇するボッシュガスの熱容量）で表される熱流比が上昇する。この結果、炉内を上昇する炉内ガスの温度が低下しやすくなり、結果として、炉頂ガス温度が低下しやすくなる。この結果、ベース操業に比べて炉頂ガス温度が低下する可能性がある。ただし、高濃度水素含有ガス中の水素ガスの吹込み量をさらに増加させていくと、概ね３００Ｎｍ３／ｔを境界として、上述したように、吸熱反応により炉内温度が低下し炉内還元効率が低下し始める。このような還元効率の低下を防ぐために還元材比を上げて操業することになるが、還元材比を上げると炉内への投入熱量が増加し、炉頂ガス温度が上昇傾向となるため、炉頂ガス温度が増加に転じる。 As is clear from FIG. 13, there is a certain correlation between the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas and the amount of change in the furnace top gas temperature. For example, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is increased, the tuyere temperature Tf decreases as described above. In order to make the tuyere temperature Tf a desired temperature, it is necessary to increase the oxygen enrichment rate and perform the operation. In actual operation, the flow rate of oxygen in units Nm 3 / t is adjusted to be in the oxygen-enriched rate of changing the flow rate of air in the unit Nm 3 / t without changing. Therefore, as the oxygen enrichment rate increases, the flow rate of hot air decreases. As a result, the amount of Bosch gas is reduced. In other words, as the tuyere temperature Tf rises, the amount of Bosch gas decreases. Therefore, the heat flow ratio expressed by (heat capacity of the furnace interior container falling per unit time) / (heat capacity of Bosch gas rising per unit time) increases. As a result, the temperature of the gas in the furnace that rises in the furnace tends to decrease, and as a result, the temperature of the gas at the top of the furnace tends to decrease. As a result, the temperature of the furnace top gas may be lower than that of the base operation. However, if the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is further increased, the temperature inside the furnace decreases due to the endothermic reaction, with the boundary of approximately 300 Nm 3 / t as the boundary, and the reduction efficiency inside the furnace. Begins to decline. In order to prevent such a decrease in reducing efficiency, the operation is performed by increasing the reducing agent ratio. However, if the reducing agent ratio is increased, the amount of heat input into the furnace increases and the furnace top gas temperature tends to rise. The furnace top gas temperature starts to increase.
　変形例６では、まず、変形例４と同様に吹込み量－炭素消費原単位削減割合相関を予め求める。さらに、吹込み量とベース操業に対する炉頂ガス温度の変化量との相関である吹込み量－炉頂ガス温度変化量相関を求める。 In the modified example 6, first, the injection amount-carbon consumption intensity reduction ratio correlation is obtained in advance in the same manner as in the modified example 4. Furthermore, the correlation between the blown amount and the change in the top gas temperature with respect to the base operation, which is the correlation between the blown amount and the change in the top gas temperature, is obtained.
　例えば、高濃度水素含有ガスの吹込み温度を含む現状の高炉操業を反映した高炉操業シミュレーションにより何点かの吹込み量のそれぞれに対する炉頂ガス温度の変化量を求める。具体的な方法は後述する実施例と同様の方法であればよい。 For example, the amount of change in the furnace top gas temperature for each of several injection amounts is obtained by a blast furnace operation simulation that reflects the current blast furnace operation including the injection temperature of high-concentration hydrogen-containing gas. The specific method may be the same as that of the examples described later.
　ついで、横軸を単位Ｎｍ３／ｔでの高濃度水素含有ガス中の水素ガスの吹込み量、縦軸を単位℃での炉頂ガス温度の変化量である△炉頂ガス温度とした平面上に上記方法で求めた値をプロットする。ついで、これらのプロットの近似曲線を例えば最小二乗法で求め、この近似曲線、より具体的には、近似曲線を示す関係式を上述した吹込み量－炉頂ガス温度変化量相関とすればよい。吹込み量－炉頂ガス温度変化量相関は、羽口前温度Ｔｆ毎に求めることが好ましい。 Next, the horizontal axis is the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas in the unit Nm 3 / t, and the vertical axis is the amount of change in the furnace top gas temperature in the unit ° C. The values obtained by the above method are plotted above. Then, the approximate curves of these plots may be obtained by, for example, the least squares method, and the relational expression showing the approximate curves, more specifically, the approximate curves may be used as the above-mentioned injection amount-furnace top gas temperature change amount correlation. .. The correlation between the amount of blown gas and the amount of change in the temperature of the top gas is preferably obtained for each tuyere front temperature Tf.
　ついで、現状の操業よりも炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが大きくなり、すなわち、炭素消費量が低減し、かつ炉頂ガス温度の変化量が所定範囲内の値となる吹込み量を吹込み量－炭素消費原単位削減割合相関及び吹込み量－炉頂ガス温度変化量相関に基づいて決定する。ここで、所定範囲は、例えば－２０～＋２０℃程度とされるが、これに限定されない。ついで、高濃度水素含有ガスを当該決定された吹込み量で羽口から吹き込む。これにより、炉頂ガス温度の変化量を所定範囲内の値としつつ、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃをより確実に大きくすることができる。 Next, the reduction rate Input ΔC of the carbon consumption intensity is larger than that of the current operation, that is, the amount of injection is such that the carbon consumption is reduced and the amount of change in the furnace top gas temperature is within the predetermined range. Determined based on the correlation between the amount of injection and the reduction rate of carbon consumption intensity and the correlation between the amount of injection and the amount of change in the temperature of the top gas. Here, the predetermined range is, for example, about −20 to + 20 ° C., but is not limited thereto. Then, a high-concentration hydrogen-containing gas is blown from the tuyere at the determined blowing amount. As a result, it is possible to more reliably increase the reduction rate Input ΔC of the carbon consumption intensity while keeping the amount of change in the furnace top gas temperature within a predetermined range.
　ここで、上記変形例４～６において、高濃度水素含有ガス中の水素ガスの吹込み量と対になるパラメータは必ずしも炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃに限られない。つまり、高濃度水素含有ガス中の水素ガスの吹込み量と対になるパラメータは炭素消費量に関するパラメータ、すなわち、炭素消費パラメータであればどのようなものであってもよい。炭素消費量が減少すれば、ＣＯ２排出量を削減することができるからである。このような炭素消費パラメータとしては、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃの他、炭素消費原単位、還元材比、還元材比の削減割合等が挙げられる。還元材比の削減割合とは、ベース操業に対する還元材比の削減割合であり、求め方は炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃの求め方と同様である。 Here, in the above modifications 4 to 6, the parameter paired with the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is not necessarily limited to the reduction rate Input ΔC of the carbon consumption intensity. That is, the parameter paired with the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas may be any parameter related to carbon consumption, that is, any carbon consumption parameter. This is because if carbon consumption is reduced, CO 2 emissions can be reduced. Examples of such a carbon consumption parameter include a reduction rate of carbon consumption intensity, Input ΔC, a carbon consumption intensity, a reducing agent ratio, a reduction rate of the reducing agent ratio, and the like. The reduction ratio of the reducing agent ratio is the reduction ratio of the reducing agent ratio with respect to the base operation, and the method of obtaining it is the same as the method of obtaining the reduction ratio Input ΔC of the carbon consumption intensity.
　さらに、変形例５と変形例６は組み合わせてもよい。これにより、圧力損失の変化量及び炉頂ガス温度の変化量を所定範囲内の値としつつ、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃをより確実に大きくすることができる。 Further, the modification 5 and the modification 6 may be combined. As a result, while keeping the amount of change in pressure loss and the amount of change in furnace top gas temperature within a predetermined range, the reduction rate Input ΔC of the carbon consumption intensity can be increased more reliably.
　次に、本実施形態の実施例について説明する。本実施例では、高炉操業シミュレーションを行うことで、本実施形態に係る高炉の操業方法によって炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが大きくなる、すなわちＣＯ２排出量が削減されることを確認した。 Next, an example of this embodiment will be described. In this embodiment, by performing a blast furnace operation simulation, it was confirmed that the reduction rate Input ΔC of the carbon consumption intensity increases, that is, the CO 2 emission amount is reduced, depending on the blast furnace operation method according to the present embodiment. ..
　＜１．実施例１：高濃度水素含有ガスの吹込み温度が常温～６００℃となる場合の検証＞
　上述したように、高濃度水素含有ガス中の水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関は６００℃の吹込み温度を境界として異なる挙動を示す。そこで、実施例１では、高濃度水素含有ガスの吹込み温度が６００℃以下となる場合の検証を行った。 <1. Example 1: Verification when the blowing temperature of the high-concentration hydrogen-containing gas is room temperature to 600 ° C>
As described above, the correlation between the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas and the reduction rate of carbon consumption intensity Input ΔC shows different behavior with the blowing temperature of 600 ° C. as a boundary. Therefore, in Example 1, verification was performed when the blowing temperature of the high-concentration hydrogen-containing gas was 600 ° C. or lower.
　＜１－１．シミュレーションに使用したモデル及び計算条件＞
　高炉操業シミュレーションには、Ｋｏｕｊｉ　ＴＡＫＡＴＡＮＩ、Ｔａｋａｎｏｂｕ　ＩＮＡＤＡ、Ｙｕｔａｋａ　ＵＪＩＳＡＷＡ、「Ｔｈｒｅｅ－ｄｉｍｅｎｓｉｏｎａｌ　Ｄｙｎａｍｉｃ　Ｓｉｍｕｌａｔｏｒ　ｆｏｒ　Ｂｌａｓｔ　Ｆｕｒｎａｃｅ」、ＩＳＩＪ　Ｉｎｔｅｒｎａｔｉｏｎａｌ、Ｖｏｌ．３９（１９９９）、Ｎｏ．１、ｐ．１５－２２などに示される、所謂「高炉数学モデル」を用いた。この高炉数学モデルは、概略的には、高炉の内部領域を高さ方向、径方向、周方向に分割することで複数のメッシュ（小領域）を規定し、各メッシュの挙動をシミュレーションするものである。 <1-1. Model and calculation conditions used for simulation>
For blast furnace operation simulation, Koji TAKATANI, Takanobu INADA, Yutaka UJISAWA, "Three-dimensional Dynamic Simulation for Blast Furnace", ISIJ International, Vol. 39 (1999), No. 1, p. The so-called "blast furnace mathematical model" shown in 15-22 and the like was used. This blast furnace mathematical model roughly defines a plurality of meshes (small regions) by dividing the internal region of the blast furnace into the height direction, the radial direction, and the circumferential direction, and simulates the behavior of each mesh. is there.
　高炉数学モデルにおいては、高濃度水素含有ガスの吹込み量は、羽口から吹き込まれる高濃度水素含有ガスのガス量として設定される。このうち、高濃度水素含有ガス中の水素ガスの吹込み量は、高濃度水素含有ガスの吹込み量に単位ｍｏｌ％での水素ガスの比率を乗じた量として設定される。高濃度水素含有ガスの吹込み温度は、高濃度水素含有ガスを羽口から吹き込む際の高濃度水素含有ガスの温度として設定される。羽口前温度Ｔｆは、各種ガスの燃焼熱、送風顕熱、羽口先（羽口前）に流入するコークスの温度、各種反応熱等を考慮した結果として算出される。圧力損失は、炉内充填層の圧力損失としてｅｒｇｕｎ式を用いて算出される。炉頂ガス温度は、炉内装入物の最表層（もっとも上側の層）におけるガス温度として算出される。 In the blast furnace mathematical model, the amount of high-concentration hydrogen-containing gas blown is set as the amount of high-concentration hydrogen-containing gas blown from the tuyere. Of these, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is set as the amount obtained by multiplying the amount of high-concentration hydrogen-containing gas blown by the ratio of hydrogen gas in the unit mol%. The blowing temperature of the high-concentration hydrogen-containing gas is set as the temperature of the high-concentration hydrogen-containing gas when the high-concentration hydrogen-containing gas is blown from the tuyere. The tuyere temperature Tf is calculated as a result of considering the combustion heat of various gases, the sensible heat of the blast, the temperature of coke flowing into the tuyere tip (in front of the tuyere), various reaction heats, and the like. The pressure loss is calculated by using the ergun equation as the pressure loss of the filling layer in the furnace. The furnace top gas temperature is calculated as the gas temperature in the outermost layer (uppermost layer) of the furnace interior container.
　計算条件を表１に示す。表１中のコークス比は溶銑１トンあたりに使用するコークス量である。また、高濃度水素含有ガスを吹き込まないベース操業の諸元を表２に示す。表１、２に示される通り、本実施例では羽口前温度Ｔｆを２０００℃、２１００℃、２２００℃の何れかとした。また、高濃度水素含有ガス中の水素ガスの吹込み量を０～６００Ｎｍ３／ｔとした。また、全操業で出銑比と溶銑温度が一定となるよう、送風量、酸素富化率、ＰＣ（微粉炭）吹込み量を調整した。 The calculation conditions are shown in Table 1. The coke ratio in Table 1 is the amount of coke used per ton of hot metal. Table 2 shows the specifications of the base operation in which a high-concentration hydrogen-containing gas is not blown. As shown in Tables 1 and 2, in this example, the tuyere temperature Tf was set to any of 2000 ° C., 2100 ° C., and 2200 ° C. The amount of hydrogen gas blown into the high-concentration hydrogen-containing gas was set to 0 to 600 Nm 3 / t. In addition, the amount of air blown, the oxygen enrichment rate, and the amount of PC (pulverized coal) blown were adjusted so that the hot metal output ratio and the hot metal temperature were constant in all operations.
Figure JPOXMLDOC01-appb-T000001
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Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　なお、鉄系原料はすべて焼結鉱とした。また、焼結鉱の組成はＴ－Ｆｅ：５８．５％、ＦｅＯ：７．５％、Ｃ／Ｓ：１．９、Ａｌ２Ｏ３：１．７％とした。また、コークスについては、Ｃ：８７．２％、Ａｓｈ：１２．６％を使用する場合を想定した。なお、上記の「％」はいずれも「質量％」を表す。 All iron-based raw materials were sintered ore. The composition of the sinter T-Fe: 58.5%, FeO : 7.5%, C / S: 1.9, Al 2 O 3: was 1.7%. As for coke, it was assumed that C: 87.2% and Ash: 12.6% were used. In addition, all of the above "%" represent "mass%".
　＜１－２．実施例１－１：高濃度水素含有ガスの吹込み温度が常温～６００℃であり、高濃度水素含有ガスが純水素ガスであるケース＞
　実施例１－１では、高濃度水素含有ガスの吹込み温度が６００℃以下の条件で、高濃度水素含有ガスを純水素ガスとして、純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を計算した。結果を図２～図５に示す。 <1-2. Example 1-1: A case where the blowing temperature of the high-concentration hydrogen-containing gas is room temperature to 600 ° C. and the high-concentration hydrogen-containing gas is pure hydrogen gas>
In Example 1-1, under the condition that the blowing temperature of the high-concentration hydrogen-containing gas is 600 ° C. or lower, the high-concentration hydrogen-containing gas is regarded as pure hydrogen gas, and the amount of pure hydrogen gas blown and the reduction ratio of the carbon consumption intensity are reduced. The correlation with Input ΔC was calculated. The results are shown in FIGS. 2 to 5.
　図２～図５に示される通り、吹込み温度が常温以上６００℃以下の範囲では、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは、吹込み量の増加に伴って単純に増加するものではなく、吹込み量がある程度増加すると飽和し減少に転じることがわかった。そして、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが飽和し減少に転じる際の吹込み量は吹込み温度によってやや異なることがわかった。すなわち、吹込み温度毎に吹込み量の適正範囲が存在することがわかった。そして、かかる適正範囲は、吹込み温度が常温～３００℃となる場合には、２００～５００Ｎｍ３／ｔとなり、吹込み温度が３００℃超６００℃以下となる場合には、１４５Ｎｍ３／ｔ以上となった。また、図４及び図５に示される通り、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは、吹込み量の増加に伴って単純に増加するものではなく、吹込み温度が６００℃では、吹込み量が６００Ｎｍ３／ｔ程度で飽和し、吹込み温度が３５０℃では、吹込み量が３００Ｎｍ３／ｔ程度をピークに吹込み量の増加とともに減少に転じることがわかった。そして、吹込み温度が３００℃超６００℃以下となる場合には、吹込み量が１４５Ｎｍ３／ｔ以上の適正範囲内となる場合に、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを７％以上とすることが可能となった。さらに、図２～図５に示される通り、同一の吹込み量に対する炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは、羽口前温度Ｔｆによって異なり、羽口前温度Ｔｆが２０００℃となる場合にもっとも大きくなることもわかった。このような現象が得られる理由は上述した通りである。 As shown in FIGS. 2 to 5, when the blowing temperature is in the range of room temperature or higher and 600 ° C or lower, the reduction rate of carbon consumption intensity Input ΔC does not simply increase as the blowing amount increases. It was found that when the amount of blown air increased to some extent, it became saturated and started to decrease. Then, it was found that the amount of blown air when the reduction rate of carbon consumption intensity, Input ΔC, was saturated and started to decrease was slightly different depending on the blown temperature. That is, it was found that there is an appropriate range of the blowing amount for each blowing temperature. The appropriate range is 200 to 500 Nm 3 / t when the blowing temperature is room temperature to 300 ° C, and 145 Nm 3 / t or more when the blowing temperature is more than 300 ° C and 600 ° C or less. It became. Further, as shown in FIGS. 4 and 5, the reduction rate Input ΔC of the carbon consumption intensity does not simply increase with the increase in the blowing amount, and when the blowing temperature is 600 ° C., the blowing is performed. It was found that the amount was saturated at about 600 Nm 3 / t, and when the blowing temperature was 350 ° C., the blowing amount peaked at about 300 Nm 3 / t and started to decrease as the blowing amount increased. When the blowing temperature is more than 300 ° C and 600 ° C or less, the reduction rate of carbon consumption intensity is 7% or more when the blowing amount is within the appropriate range of 145 Nm 3 / t or more. It became possible to. Further, as shown in FIGS. 2 to 5, the reduction ratio Input ΔC of the carbon consumption intensity with respect to the same blowing amount differs depending on the tuyere temperature Tf, and when the tuyere temperature Tf becomes 2000 ° C. It was also found to be the largest. The reason why such a phenomenon is obtained is as described above.
　したがって、本実施形態に係る高炉の操業方法に従って高濃度水素含有ガスを高炉内に吹き込むことで、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを大きくすることができ、ひいてはＣＯ２排出量を大きく削減することができる。 Therefore, by blowing a high-concentration hydrogen-containing gas into the blast furnace according to the operation method of the blast furnace according to the present embodiment, the reduction rate of carbon consumption intensity Input ΔC can be increased, and CO 2 emissions can be significantly reduced. can do.
　＜１－３．実施例１－２＞
　実施例１－２では、高濃度水素含有ガスに水素ガス以外のガスが含まれていても純水素ガスの場合と同様の操業が可能であることを確認した。具体的には、高濃度水素含有ガスとして８０ｍｏｌ％の水素ガス及び２０ｍｏｌ％の窒素ガスで構成される８０ｍｏｌ％Ｈ２－２０ｍｏｌ％Ｎ２ガスを想定した。そして、吹込み温度を２５℃、羽口前温度Ｔｆを２１００℃として実施例１と同様に高炉操業シミュレーションを行った。結果を図１１に示す。図１１は、純水素ガス（１００ｍｏｌ％Ｈ２ガス）の計算結果と８０ｍｏｌ％Ｈ２－２０ｍｏｌ％Ｎ２ガスの計算結果とを対比して示す。なお、図１１の横軸は、混合ガスの流量を純水素ガスに換算したものであり、すなわち、８０ｍｏｌ％Ｈ２－２０ｍｏｌ％Ｎ２ガスの流量に８０ｍｏｌ％を乗じた値である。図１１から明らかな通り、８０ｍｏｌ％Ｈ２－２０ｍｏｌ％Ｎ２ガスについても、純水素ガスに換算した吹込み量の適正範囲は純水素ガスの場合と変わらず、効果代のみ若干低下していることがわかった。したがって、高濃度水素含有ガスに水素ガス以外のガスが含まれていても純水素ガスの場合と同様の操業が可能であることがわかった。また、効果は若干落ちるものの、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃも大きくできることがわかった。 <1-3. Example 1-2>
In Example 1-2, it was confirmed that even if the high-concentration hydrogen-containing gas contained a gas other than hydrogen gas, the same operation as in the case of pure hydrogen gas was possible. Specifically, assuming a 80mol% H 2 -20mol% N 2 gas composed of 80 mol% of hydrogen gas and 20 mol% of nitrogen gas as a high-concentration hydrogen-containing gas. Then, the blast furnace operation simulation was performed in the same manner as in Example 1 with the blowing temperature being 25 ° C. and the tuyere front temperature Tf being 2100 ° C. The results are shown in FIG. Figure 11 shows by comparing the calculation result of the calculation results of pure hydrogen gas (100 mol% H 2 gas) and 80mol% H 2 -20mol% N 2 gas. The horizontal axis of FIG. 11, the flow rate of the mixed gas is obtained by converting the pure hydrogen gas, i.e., a value obtained by multiplying the 80 mol% to the flow rate of 80mol% H 2 -20mol% N 2 gas. As is clear from FIG. 11, for the 80mol% H 2 -20mol% N 2 gas, the proper scope of the blowing amount in terms of pure hydrogen gas is maintained at the case of pure hydrogen gas, it is slightly lowered only effect allowance I understood it. Therefore, it was found that even if the high-concentration hydrogen-containing gas contains a gas other than hydrogen gas, the same operation as in the case of pure hydrogen gas is possible. It was also found that the reduction rate Input ΔC of the carbon consumption intensity can be increased, although the effect is slightly reduced.
　＜１－４．実施例１－３＞
　実施例１－３では、高濃度水素含有ガスとして常温の純水素ガスを使用し、何点かの吹込み量のそれぞれに対する圧力損失の変化量（ベース操業に対する圧力損失の変化量）を求めた。その結果を図１２に示す。図１２から明らかな通り、純水素ガスの吹込み量と圧力損失の変化量との間には一定の相関があることがわかった。例えば、羽口前温度Ｔｆが低い場合、ベース操業に対して圧力損失が大きくなる可能性があることがわかった。ただし、純水素ガスの吹込み量が増加すると圧力損失が減少した。より具体的には、羽口前温度Ｔｆが２０００℃となり、かつ吹込み量が１００～１５０Ｎｍ３／ｔとなった場合、圧力損失がベース操業と比べて１０～２０ｋＰａ程度上昇した。これは、上述した所定範囲外の値であった。ただし、吹込み量が２００以上Ｎｍ３／ｔまで上昇すると、圧力損失がベース操業の値と同程度またはそれ以下となった。このような現象が生じる理由は上述した通りである。したがって、吹込み温度が所定値であるときの、高濃度水素含有ガス中の水素ガスの吹込み量とベース操業に対する圧力損失の変化量との相関である吹込み量－圧力損失変化量相関を羽口前温度Ｔｆ毎に予め求めておき、現状の操業よりも炭素消費量が低減し、かつ、圧力損失の変化量が所定範囲内の値となる高濃度水素含有ガス中の水素ガスの吹込み量を当該吹込み量－炭素消費パラメータ相関及び吹込み量－圧力損失変化量相関に基づいて決定することで、圧力損失の増大を抑制することができ、安定した操業を行いながら炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを大きくすることができることがわかった。
　そして、高濃度水素含有ガスとして常温の純水素ガスを使用し、その吹込み量が２００Ｎｍ３／ｔ以上５００Ｎｍ３／ｔ以下の条件では、図１２に示すように、圧力損失の増大を抑制でき、安定した操業を行いながら炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを大きくすることができることがわかった。常温以上３００℃以下の純水素ガスであれば、その吹込み量が２００Ｎｍ３／ｔまで上昇すると、圧力損失がベース操業の値と同程度またはそれ以下となることがわかった。同様に、３００℃超６００℃以下の純水素の吹込み量が１４５Ｎｍ３／ｔ以上の場合、６００℃超９００℃以下の純水素の吹込み量が１２５Ｎｍ３／ｔ以上の場合、９００℃超１２００℃以下の純水素の吹込み量が１１０Ｎｍ３／ｔ以上の場合、および、１２００℃超の純水素の吹込み量が１００Ｎｍ３／ｔ以上の場合でも、圧力損失の増大を抑制でき、安定した操業を行いながら炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを大きくすることができることがわかった。 <1-4. Example 1-3>
In Example 1-3, pure hydrogen gas at room temperature was used as the high-concentration hydrogen-containing gas, and the amount of change in pressure loss with respect to each of several blowing amounts (the amount of change in pressure loss with respect to the base operation) was determined. .. The result is shown in FIG. As is clear from FIG. 12, it was found that there is a certain correlation between the amount of pure hydrogen gas blown and the amount of change in pressure loss. For example, it was found that when the tuyere temperature Tf is low, the pressure loss may be large with respect to the base operation. However, the pressure loss decreased as the amount of pure hydrogen gas blown increased. More specifically, when the tuyere temperature Tf was 2000 ° C. and the blowing amount was 100 to 150 Nm 3 / t, the pressure loss increased by about 10 to 20 kPa as compared with the base operation. This was a value outside the predetermined range described above. However, when the blow rate increased to 200 or more and Nm 3 / t, the pressure loss became equal to or less than the value of the base operation. The reason why such a phenomenon occurs is as described above. Therefore, when the blowing temperature is a predetermined value, the blowing amount-pressure loss change amount correlation, which is the correlation between the blowing amount of hydrogen gas in the high concentration hydrogen-containing gas and the change amount of the pressure loss with respect to the base operation, is obtained. Blow of hydrogen gas in high-concentration hydrogen-containing gas, which is obtained in advance for each tuyere temperature Tf, carbon consumption is reduced compared to the current operation, and the amount of change in pressure loss is within a predetermined range. By determining the filling amount based on the blowing amount-carbon consumption parameter correlation and the blowing amount-pressure loss change amount correlation, it is possible to suppress the increase in pressure loss, and the carbon consumption source while performing stable operation. It was found that the unit reduction rate Input ΔC can be increased.
Then, using pure hydrogen gas at normal temperature as high concentration hydrogen-containing gas, in the blowing amount is less than 200 Nm 3 / t or more 500 Nm 3 / t condition, as shown in FIG. 12, can suppress an increase in pressure loss It was found that the reduction rate Input ΔC of the carbon consumption intensity can be increased while performing stable operation. It was found that in the case of pure hydrogen gas of room temperature or higher and 300 ° C. or lower, when the blown amount increased to 200 Nm 3 / t, the pressure loss became equal to or lower than the value of the base operation. Similarly, when the amount of pure hydrogen blown above 300 ° C and 600 ° C or less is 145 Nm 3 / t or more, when the amount of pure hydrogen blown above 600 ° C and 900 ° C or less is 125 Nm 3 / t or more, it exceeds 900 ° C. Even when the amount of pure hydrogen blown at 1200 ° C or lower is 110 Nm 3 / t or more, and when the amount of pure hydrogen blown over 1200 ° C is 100 Nm 3 / t or more, the increase in pressure loss can be suppressed and stable. It was found that the reduction rate of carbon consumption intensity Input ΔC can be increased while performing the above-mentioned operation.
　したがって、本実施形態に係る高炉の操業方法に従って高濃度水素含有ガスを高炉内に吹き込むことで、圧力損失の変化量を所定範囲内の値としつつ、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを大きくすることができることがわかった。 Therefore, by blowing a high-concentration hydrogen-containing gas into the blast furnace according to the operation method of the blast furnace according to the present embodiment, the reduction rate of carbon consumption intensity Imput ΔC is set while keeping the amount of change in pressure loss within a predetermined range. It turns out that it can be made larger.
　＜１－５．実施例１－４＞
　実施例１－４では、高濃度水素含有ガスとして常温の純水素ガスを使用し、何点かの吹込み量のそれぞれに対する炉頂ガス温度の変化量（ベース操業に対する炉頂ガス温度の変化量）を求めた。その結果を図１３に示す。図１３から明らかな通り、純水素ガスの吹込み量と炉頂ガス温度の変化量との間には一定の相関があることがわかった。例えば、羽口前温度Ｔｆが上昇すると、ベース操業に比べて炉頂ガス温度が低下した。具体的には、羽口前温度Ｔｆが２１００℃となり、かつ吹込み量が２５０～３００Ｎｍ３／ｔとなる場合、炉頂ガス温度の変化量が上述した所定範囲外の値となった。ただし、吹込み量が２００Ｎｍ３／ｔまで減少すれば、炉頂ガス温度の変化量が所定範囲内の値となった。このような現象が生じる理由は上述した通りである。よって、操業の効率性等を重視する場合には、純水素ガスの吹込み量と炉頂ガス温度の変化量との間の相関を考慮して、吹込み量を調整すればよい。したがって、吹込み温度が所定値であるときの、高濃度水素含有ガス中の水素ガスの吹込み量とベース操業に対する炉頂ガス温度の変化量との相関である吹込み量－炉頂ガス温度変化量相関を羽口前温度毎に予め求めておき、現状の操業よりも炭素消費量が低減し、かつ、炉頂ガス温度の変化量が所定範囲内の値となる高濃度水素含有ガス中の水素ガスの吹込み量を吹込み量－炭素消費パラメータ相関及び吹込み量－炉頂ガス温度変化量相関に基づいて決定することで、操業の効率性の低下を抑制することができることが分かった。 <1-5. Example 1-4>
In Example 1-4, pure hydrogen gas at room temperature is used as the high-concentration hydrogen-containing gas, and the amount of change in the top gas temperature with respect to each of several blown amounts (the amount of change in the top gas temperature with respect to the base operation). ) Was asked. The result is shown in FIG. As is clear from FIG. 13, it was found that there is a certain correlation between the amount of pure hydrogen gas blown in and the amount of change in the furnace top gas temperature. For example, when the tuyere temperature Tf increased, the furnace top gas temperature decreased as compared with the base operation. Specifically, when the tuyere front temperature Tf was 2100 ° C. and the blowing amount was 250 to 300 Nm 3 / t, the amount of change in the furnace top gas temperature was a value outside the above-mentioned predetermined range. However, when the blown amount decreased to 200 Nm 3 / t, the amount of change in the furnace top gas temperature became a value within a predetermined range. The reason why such a phenomenon occurs is as described above. Therefore, when emphasizing the efficiency of operation, the blowing amount may be adjusted in consideration of the correlation between the blowing amount of pure hydrogen gas and the change amount of the furnace top gas temperature. Therefore, when the blowing temperature is a predetermined value, the blowing amount-the top gas temperature, which is the correlation between the blowing amount of hydrogen gas in the high-concentration hydrogen-containing gas and the change in the furnace top gas temperature with respect to the base operation. The change amount correlation is obtained in advance for each tuyere temperature, and in high-concentration hydrogen-containing gas where the carbon consumption is reduced compared to the current operation and the change amount of the furnace top gas temperature is within a predetermined range. It was found that the decrease in operational efficiency can be suppressed by determining the amount of hydrogen gas blown in based on the amount of blown hydrogen-carbon consumption parameter correlation and the amount of blown hydrogen-relationship of the temperature change of the furnace top gas. It was.
　＜２．実施例２：高濃度水素含有ガスの吹込み温度が６００℃超となる場合の検証＞
　実施例２では、高濃度水素含有ガスの吹込み温度が６００℃超となる場合の検証を行った。 <2. Example 2: Verification when the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C>
In Example 2, the case where the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C. was verified.
　＜２－１．シミュレーションに使用したモデル及び計算条件＞
　高炉操業シミュレーションには、実施例１と同様の高炉数学モデルを用いた。計算条件を表３に示す。表３に示す通り、計算条件は実施例１とほぼ同様であるが、コークス比は実施例１と異なる条件とした。すなわち、実施例２では、コークス比は微粉炭吹込み量が０ｔｏｎ／ｈより大きい場合には３００ｋｇ／ｔで一定とし、微粉炭吹込み量が０ｔｏｎ／ｈとなる場合（すなわち、微粉炭比が０となる場合）には変動させることとした。つまり、微粉炭吹込み量が０ｔｏｎ／ｈとなる場合、コークス比によって炉温を調整した。 <2-1. Model and calculation conditions used for simulation>
The same blast furnace mathematical model as in Example 1 was used for the blast furnace operation simulation. The calculation conditions are shown in Table 3. As shown in Table 3, the calculation conditions were almost the same as those in Example 1, but the coke ratio was different from that in Example 1. That is, in Example 2, the coke ratio is constant at 300 kg / t when the pulverized coal injection amount is larger than 0 ton / h, and the pulverized coal injection amount is 0 ton / h (that is, the pulverized coal ratio is 0 ton / h). When it becomes 0), it is decided to change. That is, when the amount of pulverized coal blown was 0 ton / h, the furnace temperature was adjusted by the coke ratio.
　上述したように、高濃度水素含有ガスの吹込み温度を高め、かつ吹き込み量を多くした場合、微粉炭吹込み量が０ｔｏｎ／ｈとなりうる。この場合、コークス比を低減することで、さらなる炭素消費原単位の削減が可能となる。また、高濃度水素含有ガス中の水素ガスの吹込み量を０～１０００Ｎｍ３／ｔとした。また、高濃度水素含有ガスの吹込み温度を６００℃超１４００℃以下とした。なお、高濃度水素含有ガスを吹き込まないベース操業の諸元は実施例１と同様とした。その他の諸条件は実施例１と同様とした。例えば、全操業で出銑比と溶銑温度が一定となるよう、送風量、酸素富化率、ＰＣ（微粉炭）吹込み量を調整した。鉄系原料は実施例１で使用した焼結鉱とした。 As described above, when the blowing temperature of the high-concentration hydrogen-containing gas is raised and the blowing amount is increased, the pulverized coal blowing amount can be 0 ton / h. In this case, by reducing the coke ratio, it is possible to further reduce the carbon consumption intensity. The amount of hydrogen gas blown into the high-concentration hydrogen-containing gas was set to 0 to 1000 Nm 3 / t. Further, the blowing temperature of the high-concentration hydrogen-containing gas was set to more than 600 ° C and 1400 ° C or less. The specifications of the base operation in which the high-concentration hydrogen-containing gas was not blown were the same as in Example 1. Other conditions were the same as in Example 1. For example, the amount of air blown, the oxygen enrichment rate, and the amount of PC (pulverized coal) blown were adjusted so that the hot metal output ratio and the hot metal temperature were constant in all operations. The iron-based raw material was the sinter used in Example 1.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　＜２－２．実施例２－１：高濃度水素含有ガスの吹込み温度が６００℃超であり、高濃度水素含有ガスが純水素ガスであるケース＞
　実施例２－１では、高濃度水素含有ガスを純水素ガスとして、純水素ガスの吹込み量と炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃとの相関を計算した。結果を図６～図１０に示す。 <2-2. Example 2-1: Case where the blowing temperature of the high-concentration hydrogen-containing gas is over 600 ° C. and the high-concentration hydrogen-containing gas is pure hydrogen gas>
In Example 2-1 using a high-concentration hydrogen-containing gas as pure hydrogen gas, the correlation between the amount of pure hydrogen gas blown and the reduction rate Input ΔC of the carbon consumption intensity was calculated. The results are shown in FIGS. 6 to 10.
　図６～図１０に示される通り、高濃度水素含有ガス中の水素ガスの吹込み量をベース操業の０Ｎｍ３／ｔから増加させていくと炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが増加することがわかった。さらに、高濃度水素含有ガス中の水素ガスの吹込み量の増加に伴って炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃの上昇割合（吹き込み量の単位上昇量に対する炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃの上昇量）は減少するものの、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃは減少に転じることがなかった。これは高濃度水素含有ガスの吹き込み温度が６００℃以下となる場合と明らかに異なる挙動であった。 As shown in FIGS. 6 to 10, when the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is increased from 0 Nm 3 / t in the base operation, the reduction rate of carbon consumption intensity Imput ΔC increases. I understood it. Furthermore, as the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas increases, the reduction rate of carbon consumption intensity Output △ C increase rate (reduction rate of carbon consumption intensity to the unit increase amount of injection amount Input △ Although the amount of increase in C) decreased, the reduction rate of carbon consumption intensity Input ΔC did not start to decrease. This behavior was clearly different from the case where the blowing temperature of the high-concentration hydrogen-containing gas was 600 ° C. or lower.
　なお、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが７％以上となる範囲は高濃度水素含有ガスの吹込み温度毎に異なっていた。具体的には、吹込み温度が６００℃超９００℃以下となる場合には、高濃度水素含有ガス中の水素ガスの吹込み量が１２５Ｎｍ３／ｔ以上の範囲内の値となる場合に、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが７％以上となった。また、吹込み温度が９００℃超１２００℃以下となる場合には、高濃度水素含有ガス中の水素ガスの吹込み量が１１０Ｎｍ３／ｔ以上の範囲内の値となる場合に、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが７％以上となった。吹込み温度が１２００℃超となる場合には、高濃度水素含有ガス中の水素ガスの吹込み量が１００Ｎｍ３／ｔ以上の範囲内の値となる場合に、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃが７％以上となった。 The range in which the reduction rate Input ΔC of the carbon consumption intensity was 7% or more was different depending on the blowing temperature of the high-concentration hydrogen-containing gas. Specifically, when the blowing temperature is more than 600 ° C. and 900 ° C. or lower, the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is within the range of 125 Nm 3 / t or more. The reduction rate of carbon consumption intensity Input ΔC was 7% or more. Further, when the blowing temperature is more than 900 ° C. and 1200 ° C. or lower, the carbon consumption source is when the blowing amount of hydrogen gas in the high-concentration hydrogen-containing gas is within the range of 110 Nm 3 / t or more. The unit reduction rate, Input ΔC, was 7% or more. When the blowing temperature exceeds 1200 ° C, when the blowing amount of hydrogen gas in the high-concentration hydrogen-containing gas is within the range of 100 Nm 3 / t or more, the reduction rate of carbon consumption intensity Input ΔC was 7% or more.
　＜２－３．その他の試験＞
　純水素ガスの吹込み温度を９００℃として実施例１－３、１－４と同様の試験を行った。この結果、純水素ガスの吹込み温度が９００℃となる場合にも、純水素ガスの吹込み量と圧力損失の変化量または炉頂ガス温度の変化量との間に一定の相関があることが確認できた。 <2-3. Other tests>
The same test as in Examples 1-3 and 1-4 was performed with the blowing temperature of pure hydrogen gas set to 900 ° C. As a result, even when the blowing temperature of pure hydrogen gas reaches 900 ° C., there is a certain correlation between the amount of pure hydrogen gas blown and the amount of change in pressure loss or the amount of change in furnace top gas temperature. Was confirmed.
　したがって、本実施形態に係る高炉の操業方法に従って高濃度水素含有ガスを高炉内に吹き込むことで、炉頂ガス温度の変化量を所定範囲内の値としつつ、炭素消費原単位の削減割合Ｉｎｐｕｔ　△Ｃを大きくすることができる。 Therefore, by blowing a high-concentration hydrogen-containing gas into the blast furnace according to the operation method of the blast furnace according to the present embodiment, the amount of change in the furnace top gas temperature is set to a value within a predetermined range, and the reduction rate of carbon consumption intensity is Imput Δ. C can be increased.
　以上、添付図面を参照しながら本発明の好適な実施形態について詳細に説明したが、本発明はかかる例に限定されない。本発明の属する技術の分野における通常の知識を有する者であれば、特許請求の範囲に記載された技術的思想の範疇内において、各種の変更例または修正例に想到し得ることは明らかであり、これらについても、当然に本発明の技術的範囲に属するものと了解される。 Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical idea described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.

Claims (13)

  1. 　水素ガスを８０ｍｏｌ％以上含有する高濃度水素含有ガスを、
    　前記高濃度水素含有ガスの吹込み温度が常温以上３００℃以下であり、かつ、前記高濃度水素含有ガス中の水素ガスの吹込み量が２００Ｎｍ３／ｔ以上５００Ｎｍ３／ｔ以下である条件、
    　前記高濃度水素含有ガスの吹込み温度が３００℃超６００℃以下であり、かつ、前記高濃度水素含有ガス中の水素ガスの吹込み量が１４５Ｎｍ３／ｔ以上である条件、
    　前記高濃度水素含有ガスの吹込み温度が６００℃超９００℃以下であり、かつ、前記高濃度水素含有ガスの吹込み量が１２５Ｎｍ３／ｔ以上である条件、
    　前記高濃度水素含有ガスの吹込み温度が９００℃超１２００℃以下であり、かつ、前記高濃度水素含有ガス中の水素ガスの吹込み量が１１０Ｎｍ３／ｔ以上である条件、または、
    　前記高濃度水素含有ガスの吹込み温度が１２００℃超であり、かつ、前記高濃度水素含有ガス中の水素ガスの吹込み量が１００Ｎｍ３／ｔ以上である条件で、
    　羽口から吹き込むことを特徴とする、高炉の操業方法。     A high-concentration hydrogen-containing gas containing 80 mol% or more of hydrogen gas,
    The high-concentration hydrogen blowing temperature-containing gas is at 300 ° C. or less than room temperature, and the high-concentration hydrogen-containing conditions blow amount of the hydrogen gas in the gas is less than 200 Nm 3 / t or more 500 Nm 3 / t,
    The condition that the blowing temperature of the high-concentration hydrogen-containing gas is more than 300 ° C. and 600 ° C. or less, and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 145 Nm 3 / t or more.
    The condition that the blowing temperature of the high-concentration hydrogen-containing gas is more than 600 ° C. and 900 ° C. or less, and the blowing amount of the high-concentration hydrogen-containing gas is 125 Nm 3 / t or more.
    The condition that the blowing temperature of the high-concentration hydrogen-containing gas is more than 900 ° C. and 1200 ° C. or less, and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 110 Nm 3 / t or more, or
    Under the condition that the blowing temperature of the high-concentration hydrogen-containing gas is more than 1200 ° C. and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 100 Nm 3 / t or more.
    A method of operating a blast furnace, which is characterized by blowing from a tuyere.
  2. 　前記吹込み温度が常温以上３００℃以下であり、かつ、前記高濃度水素含有ガス中の水素ガスの吹込み量が２００Ｎｍ３／ｔ以上３００Ｎｍ３／ｔ以下であることを特徴とする、請求項１に記載の高炉の操業方法。 The claim is characterized in that the blowing temperature is room temperature or more and 300 ° C. or less, and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 200 Nm 3 / t or more and 300 Nm 3 / t or less. The method for operating a blast furnace according to 1.
  3. 　前記高濃度水素含有ガスの吹込み温度が３００℃超６００℃以下であり、かつ、前記高濃度水素含有ガス中の水素ガスの吹込み量が１４５Ｎｍ３／ｔ以上６００Ｎｍ３／ｔ以下であることを特徴とする、請求項１に記載の高炉の操業方法。 The blowing temperature of the high-concentration hydrogen-containing gas is more than 300 ° C. and 600 ° C. or less, and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 145 Nm 3 / t or more and 600 Nm 3 / t or less. The method for operating a blast furnace according to claim 1, wherein the blast furnace is operated.
  4. 　羽口前温度を２０５０℃以下とすることを特徴とする、請求項１～３の何れか１項に記載の高炉の操業方法。 The method for operating a blast furnace according to any one of claims 1 to 3, wherein the temperature in front of the tuyere is 2050 ° C. or lower.
  5. 　羽口前温度を２０５０℃超２１５０℃以下とすることを特徴とする、請求項１～３の何れか１項に記載の高炉の操業方法。 The method for operating a blast furnace according to any one of claims 1 to 3, wherein the temperature in front of the tuyere is set to more than 2050 ° C and 2150 ° C or less.
  6. 　羽口前温度を２１５０℃超２２５０℃以下とすることを特徴とする、請求項１～３の何れか１項に記載の高炉の操業方法。 The method for operating a blast furnace according to any one of claims 1 to 3, wherein the temperature in front of the tuyere is set to more than 2150 ° C and 2250 ° C or less.
  7. 　前記高濃度水素含有ガスの吹込み温度が６００℃超１４００℃以下であることを特徴とする、請求項１に記載の高炉の操業方法。 The method for operating a blast furnace according to claim 1, wherein the blowing temperature of the high-concentration hydrogen-containing gas is more than 600 ° C and 1400 ° C or less.
  8. 　前記高濃度水素含有ガスの吹込み温度が６００℃超となる場合、前記高濃度水素含有ガス中の水素ガスの吹込み量を１０００Ｎｍ３／ｔ以下とすることを特徴とする、請求項１または７に記載の高炉の操業方法。 When the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C., the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 1000 Nm 3 / t or less, according to claim 1 or 7. The method of operating a blast furnace according to 7.
  9. 　前記高濃度水素含有ガスの吹込み温度が６００℃超であり、かつ、前記高濃度水素含有ガス中の水素ガスの吹込み量が４００Ｎｍ３／ｔ以上となる場合、羽口前温度を２０５０℃以下とすることを特徴とする、請求項１、７、または８に記載の高炉の操業方法。 When the blowing temperature of the high-concentration hydrogen-containing gas exceeds 600 ° C. and the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas is 400 Nm 3 / t or more, the tuyere temperature is set to 2050 ° C. The method for operating a blast furnace according to claim 1, 7, or 8, wherein the blast furnace is operated as follows.
  10. 　水素ガスを８０ｍｏｌ％以上含有する高濃度水素含有ガスの吹込み温度が所定値であるときの、前記高濃度水素含有ガス中の水素ガスの吹込み量と炭素消費量に関する炭素消費パラメータとの相関である吹込み量－炭素消費パラメータ相関を羽口前温度毎に予め求めておき、
    　現状の操業よりも前記炭素消費量が低減する前記高濃度水素含有ガス中の水素ガスの吹込み量を前記吹込み量－炭素消費パラメータ相関に基づいて決定し、
    　前記高濃度水素含有ガスを当該決定された吹込み量で前記羽口から吹き込むことを特徴とする、高炉の操業方法。     Correlation between the amount of hydrogen gas blown into the high-concentration hydrogen-containing gas and the carbon consumption parameter related to carbon consumption when the blow-in temperature of the high-concentration hydrogen-containing gas containing 80 mol% or more of hydrogen gas is a predetermined value. The injection amount-carbon consumption parameter correlation, which is, is obtained in advance for each tuyere temperature.
    The amount of hydrogen gas blown into the high-concentration hydrogen-containing gas whose carbon consumption is reduced compared to the current operation is determined based on the blown amount-carbon consumption parameter correlation.
    A method for operating a blast furnace, which comprises blowing the high-concentration hydrogen-containing gas from the tuyere at the determined blowing amount.
  11. 　前記吹込み量－炭素消費パラメータ相関を前記吹込み温度毎に求めることを特徴とする、請求項１０に記載の高炉の操業方法。 The method for operating a blast furnace according to claim 10, wherein the blowing amount-carbon consumption parameter correlation is obtained for each blowing temperature.
  12. 　前記吹込み温度が所定値であるときの、前記高濃度水素含有ガス中の水素ガスの吹込み量とベース操業に対する圧力損失の変化量との相関である吹込み量－圧力損失変化量相関を羽口前温度毎に予め求めておき、
    　現状の操業よりも前記炭素消費量が低減し、かつ、前記圧力損失の変化量が所定範囲内の値となる前記高濃度水素含有ガス中の水素ガスの吹込み量を前記吹込み量－炭素消費パラメータ相関及び前記吹込み量－圧力損失変化量相関に基づいて決定することを特徴とする、請求項１０または１１に記載の高炉の操業方法。     When the blowing temperature is a predetermined value, the blowing amount-pressure loss change amount correlation, which is the correlation between the blowing amount of hydrogen gas in the high-concentration hydrogen-containing gas and the change amount of pressure loss with respect to the base operation, is obtained. Obtain in advance for each tuyere temperature
    The amount of hydrogen gas blown into the high-concentration hydrogen-containing gas in which the amount of carbon consumption is reduced as compared with the current operation and the amount of change in the pressure loss is within a predetermined range is the amount of blown-carbon. The method for operating a blast furnace according to claim 10 or 11, wherein the determination is made based on the consumption parameter correlation and the injection amount-pressure loss change amount correlation.
  13. 　前記吹込み温度が所定値であるときの、前記高濃度水素含有ガス中の水素ガスの吹込み量とベース操業に対する炉頂ガス温度の変化量との相関である吹込み量－炉頂ガス温度変化量相関を羽口前温度毎に予め求めておき、
    　現状の操業よりも前記炭素消費量が低減し、かつ、前記炉頂ガス温度の変化量が所定範囲内の値となる前記高濃度水素含有ガス中の水素ガスの吹込み量を前記吹込み量－炭素消費パラメータ相関及び前記吹込み量－炉頂ガス温度変化量相関に基づいて決定することを特徴とする、請求項１０～１２の何れか１項に記載の高炉の操業方法。     When the blowing temperature is a predetermined value, the blowing amount-the top gas temperature, which is the correlation between the blowing amount of hydrogen gas in the high-concentration hydrogen-containing gas and the change in the furnace top gas temperature with respect to the base operation. Obtain the change amount correlation in advance for each tuyere temperature,
    The amount of hydrogen gas blown into the high-concentration hydrogen-containing gas whose carbon consumption is reduced as compared with the current operation and the amount of change in the furnace top gas temperature is within a predetermined range is the amount of the blown amount. The method for operating a blast furnace according to any one of claims 10 to 12, characterized in that the determination is made based on the correlation between carbon consumption parameters and the correlation between the amount of blown gas and the amount of change in gas temperature at the top of the furnace.
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