WO2025121099A1 - 還元炉の操業方法および還元鉄の製造方法 - Google Patents

還元炉の操業方法および還元鉄の製造方法 Download PDF

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Publication number
WO2025121099A1
WO2025121099A1 PCT/JP2024/040539 JP2024040539W WO2025121099A1 WO 2025121099 A1 WO2025121099 A1 WO 2025121099A1 JP 2024040539 W JP2024040539 W JP 2024040539W WO 2025121099 A1 WO2025121099 A1 WO 2025121099A1
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WIPO (PCT)
Prior art keywords
reduction furnace
gas
operating
furnace
iron oxide
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PCT/JP2024/040539
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English (en)
French (fr)
Japanese (ja)
Inventor
晃太 盛家
光輝 照井
佳子 中原
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JFE Steel Corp
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JFE Steel Corp
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Priority to AU2024393059A priority Critical patent/AU2024393059A1/en
Priority to JP2025509014A priority patent/JPWO2025121099A1/ja
Publication of WO2025121099A1 publication Critical patent/WO2025121099A1/ja
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
    • C10B53/00—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form
    • C10B53/02—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form of cellulose-containing material
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B11/00—Making pig-iron other than in blast furnaces
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
    • Y02P10/143—Reduction of greenhouse gas [GHG] emissions of methane [CH4]

Definitions

  • the present invention relates to a method for operating a reduction furnace and a method for producing reduced iron.
  • the raw material of iron is mainly iron oxide such as iron ore, and a reduction process for reducing this iron ore is essential in steelworks.
  • the most common reduction process that is widespread worldwide is the blast furnace.
  • coke or pulverized coal reacts with oxygen in hot air (air heated to about 1200 ° C) at the tuyere. This reaction produces reducing gases CO and H 2 , which are used to reduce iron ore in the furnace.
  • the reducing agent ratio (the amount of coke and pulverized coal used per ton of molten iron) has been reduced to about 500 kg/t, and the reducing agent ratio has already reached almost the lower limit. Therefore, a further significant reduction in the reducing agent ratio cannot be expected.
  • a method of producing reduced iron using a vertical reduction furnace (hereinafter also referred to as a shaft furnace) is also widely used.
  • a reduction furnace is filled with agglomerated iron ore such as sintered ore or pellets as an iron oxide raw material (hereinafter also simply referred to as iron oxide).
  • a reducing gas containing CO and H2 is blown into the reduction furnace to reduce the iron oxide and produce reduced iron.
  • natural gas or the like is used as a raw material gas for the reducing gas. This raw material gas is heated and reformed in a reformer together with the furnace top gas. As a result, a reducing gas is produced.
  • the furnace top gas is a gas after being used for the reduction of iron oxide in the reduction furnace, and is generally discharged from the furnace top of the reduction furnace.
  • the generated reducing gas is blown into the reduction furnace and reacts with the iron oxide supplied from the upper part of the reduction furnace.
  • the iron oxide is reduced to produce reduced iron.
  • the reduced iron is cooled in a region below the position where the reducing gas is blown into the reduction furnace, and then discharged from the lower part of the reduction furnace.
  • the top gas remaining after the reduction of the iron oxide is discharged from the reduction furnace, for example, from the top of the furnace. After dust collection and cooling, part of the top gas is sent to the reformer as a raw material for the reformed gas. The remaining top gas is used as fuel gas for the reformer. In this method, the top gas used as fuel gas for the reformer is usually discharged outside the system.
  • Patent Document 1 describes a method in which exhaust gas from a reducing furnace and natural gas are reformed in a reformer to generate a reducing gas mainly composed of CO and H2 , and the reducing gas is injected into a reducing furnace to reduce iron oxide in the reducing furnace, thereby producing reduced iron.
  • Patent Document 2 also describes a method for producing reduced iron by partially burning a carbonaceous raw material containing, in addition to coal, either or both of biomass and waste plastics, or coal (hereinafter also referred to as the carbonaceous raw material, etc.) with oxygen to produce a reducing gas, which is then blown into a reduction furnace.
  • a carbonaceous raw material containing, in addition to coal, either or both of biomass and waste plastics, or coal (hereinafter also referred to as the carbonaceous raw material, etc.) with oxygen to produce a reducing gas, which is then blown into a reduction furnace.
  • Patent Document 2 requires combustion equipment to partially burn carbonaceous raw materials.
  • existing shaft furnaces that are commonly used do not usually have such combustion equipment. Therefore, when manufacturing a reduction furnace using the method described in Patent Document 2, large costs are incurred for expansion.
  • the present invention was developed in consideration of the above-mentioned current situation, and aims to provide a method for operating a reduction furnace that can reduce the amount of natural gas used without making major modifications to existing facilities.
  • the present invention also aims to provide a method for producing reduced iron, which produces reduced iron using the above-mentioned method for operating a reduction furnace.
  • any numerical range expressed using " ⁇ " means a range that includes the numerical values written before and after " ⁇ " as the lower and upper limits, respectively.
  • the inventors conducted extensive research to solve the above problems, and came to the following findings. That is, by simultaneously charging solid hydrocarbons, particularly solid hydrocarbons with a volatile content of 40% by mass or more, in addition to iron oxide into the reduction furnace, and preferably by appropriately controlling the mass ratio of the solid hydrocarbons to the iron oxide charged into the reduction furnace, it becomes possible to reduce the amount of natural gas used without making major modifications to existing facilities.
  • the present invention was completed based on the above findings and through further research.
  • the gist of the present invention is as follows:
  • a method for operating a reduction furnace comprising the steps of: a charging step of charging iron oxide and solid hydrocarbons into the reduction furnace; A blowing step of blowing a reducing gas containing CO and H2 into the reduction furnace; a reduction step of reducing the iron oxide in the reduction furnace to obtain reduced iron;
  • the method for operating a reduction furnace comprises the steps of:
  • the present invention makes it possible to reduce the amount of natural gas used without making major modifications to existing facilities.
  • FIG. 1 is a schematic diagram showing an example of a process for producing reduced iron.
  • the following describes a method for operating a reduction furnace according to one embodiment of the present invention.
  • a method for operating a reduction furnace includes the steps of: a charging step of charging iron oxide and solid hydrocarbons into the reduction furnace; A blowing step of blowing a reducing gas containing CO and H2 into the reduction furnace; a reduction step of reducing the iron oxide in the reduction furnace to obtain reduced iron; having Additionally, optionally, a distribution step of distributing a top gas discharged from the reducing furnace into a first top gas and a second top gas; and a reforming step of obtaining the reducing gas from the first furnace gas and the methane-containing gas as raw material gases.
  • Figure 1 is a schematic diagram showing an example of a process for producing reduced iron to which a method for operating a reduction furnace according to one embodiment of the present invention can be applied.
  • reference numeral 1 denotes a reduction furnace
  • 1a denotes iron oxide
  • 1b denotes reduced iron
  • 3 denotes a dust removal device
  • 4 denotes a dehydration device
  • 5 denotes a methane-containing gas supply section
  • 6 denotes an air supply section
  • 7 denotes a reforming device.
  • iron oxide 1a is charged from the top of a reduction furnace 1 and gradually lowered.
  • High-temperature reducing gas is blown into the reduction furnace 1 from the middle to reduce the iron oxide 1a.
  • reduced iron 1b is discharged from the bottom of the reduction furnace 1.
  • a furnace top gas containing mainly CO, CO 2 , H 2 , and H 2 O is discharged from the top of the reduction furnace 1.
  • This furnace top gas is dusted by a dust remover 3.
  • the moisture content of the furnace top gas is adjusted by a dehydrator 4, and a part of the top gas is sent to a reformer 7 as a first furnace top gas.
  • a methane-containing gas for example, natural gas
  • the supplied gas is heated in the reformer 7.
  • a reforming reaction occurs to generate a high-temperature reducing gas containing mainly CO and H 2.
  • this reducing gas is blown into the reduction furnace.
  • the remaining part of the top gas is used as a second top gas, for example, as a heating fuel in the combustion chamber of the reformer 7.
  • the second top gas after being combusted as a heating fuel is usually discharged outside the system while still containing CO 2.
  • solid hydrocarbons are charged into the reducing furnace in addition to iron oxide.
  • the solid hydrocarbons charged into the reducing furnace are heated as they descend inside the reducing furnace.
  • the solid hydrocarbons are thermally decomposed or react with CO 2 and H 2 O in the reducing furnace to become gaseous hydrocarbons, CO, and H 2 (hereinafter also referred to as gaseous hydrocarbons).
  • the gaseous hydrocarbons are consumed in the reduction reaction of iron oxide in the reducing furnace.
  • the gaseous hydrocarbons are discharged as furnace top gas and are supplied to a reformer, for example, as a raw material for reducing gas or a heating fuel. That is, it is possible to reduce the amount of methane-containing gas, specifically natural gas, used as a raw material for reducing gas, by the amount of gaseous hydrocarbons generated from the solid hydrocarbons in the reducing furnace.
  • the mass ratio of solid hydrocarbons to iron oxide charged into the reduction furnace is preferably 0.010 to 0.050.
  • kg/t-DRI is the unit of production per ton of reduced iron.
  • the solid hydrocarbon/iron oxide ratio is preferably 0.050 or less.
  • the solid hydrocarbon/iron oxide ratio is more preferably 0.015 or more.
  • the solid hydrocarbon/iron oxide ratio is more preferably 0.045 or less.
  • the solid hydrocarbon/iron oxide ratio is more preferably 0.020 to 0.045.
  • solid hydrocarbons with a high volatile content have a high moisture content, and if such solid hydrocarbons are used in excess, there is a risk that the temperature rise of the raw material charged into the reducing furnace may be hindered at the upper part of the reducing furnace. Therefore, when using solid hydrocarbons with a volatile content of 40% by mass or more, it is preferable to set the solid hydrocarbon/iron oxide ratio to 0.045 or less.
  • the type of solid hydrocarbon is not particularly limited, but examples include biomass, plastic, and coal.
  • biomass is a carbon-neutral raw material, so when biomass is used as the solid hydrocarbon, it is possible to substantially reduce the amount of CO2 emissions from the manufacturing process by the amount of biomass used, which is particularly advantageous.
  • the plastic may be unused or used.
  • used plastic conceptually includes waste plastic, plastic that is not scheduled to be disposed of, factory scraps, etc. Waste plastic in particular can be said to be a resource that should be actively utilized.
  • the volatile content of the solid hydrocarbons is 40% by mass or more (40 to 100% by mass).
  • the mass ratio of iron oxide to solid hydrocarbons is the same, using solid hydrocarbons with a larger volatile content is more effective in reducing the amount of natural gas used. It is also advantageous in terms of transportation costs. It is also advantageous in terms of reducing the amount of residue remaining in the lower part of the reduction furnace. Therefore, it is preferable to use solid hydrocarbons with a volatile content of 40% by mass or more.
  • solid hydrocarbons with a volatile content of 70% by mass or more, and even more preferable to use solid hydrocarbons with a volatile content of 85% by mass or more.
  • the upper limit of the volatile content of the solid hydrocarbons may be 100% by mass.
  • the solid hydrocarbons contain ash and moisture, and the remainder is fixed carbon.
  • the volatile content of solid hydrocarbons can be measured in accordance with JIS M 8812:2006.
  • solid hydrocarbons whose thermal decomposition temperature is preferably 900°C or less, more preferably 700°C or less.
  • solid hydrocarbons whose mass fraction of gangue components is preferably 5% or less, more preferably 3% or less.
  • biomass, plastics, coal, etc. vary depending on the type and place of origin. For this reason, it is preferable to select, for example, from various solid hydrocarbons such as biomass, plastics, and coal, those with a volatile content of 40% by mass or more.
  • the method of charging the solid hydrocarbons into the reduction furnace is not particularly limited, but for example, the solid hydrocarbons may be charged into the reduction furnace at the same time as the iron oxide through the same charging port as the iron oxide, preferably through a charging port provided at the top of the reduction furnace.
  • a reducing gas containing CO and H 2 is blown into the reduction furnace.
  • the gas composition of the reducing gas is, for example, CO: 1 to 60 vol %, H 2 : 40 to 99 vol %, and the balance: 0 to 30 vol %.
  • the iron oxide is reduced by a reducing gas to obtain reduced iron.
  • the iron oxide is also reduced by gaseous hydrocarbons generated from solid hydrocarbons charged into a direct reduction furnace.
  • the reducing gas injection temperature can be 750 to 1100°C.
  • the iron oxide used in the method for operating a reduction furnace according to one embodiment of the present invention is, for example, iron ore.
  • Specific examples include lump iron ore (lump ore) and iron oxide pellets (iron ore powder solidified into a spherical shape).
  • the quality of the iron ore used as the iron oxide, i.e., the iron content, is not particularly limited, but from the viewpoint of reduction in a shaft furnace, it is generally preferable that the quality be 65 mass% or more.
  • a method using a shaft furnace as a direct reduction ironmaking method has been described.
  • the type of reduction furnace is not limited to this, and methods using a fluidized bed, rotary kiln, rotary hearth furnace (RHF), etc. are also possible.
  • a shaft furnace is preferable as a reduction furnace because of its high production efficiency, operating rate, and operational stability.
  • the majority of direct reduction furnaces operating around the world are shaft furnace type Midrex (registered trademark) and Hyl (registered trademark).
  • the method for producing reduced iron according to one embodiment of the present invention produces reduced iron by the above-mentioned method for operating a reduction furnace. Conditions other than those described above are not particularly limited and may be performed according to conventional methods.
  • the raw material iron oxide pellets were filled into the reduction furnace at a rate of 1394 kg/t.
  • reducing gas heated to 980°C was injected from the center of the reduction furnace to reduce the iron oxide pellets and obtain reduced iron.
  • the top gas was divided into a first top gas for use as a reducing gas raw material and a second top gas for use as a heating fuel.
  • the first top gas was mixed with natural gas, and the mixed gas was supplied to a reformer to obtain a reducing gas containing CO and H2 .
  • the second top gas was combusted with air in the combustion chamber of the reformer.
  • the reducing furnace was able to be stably operated over the entire operation period of 28 days while reducing the amount of natural gas used compared to the comparative example (where reduced iron was produced under conditions in which no solid hydrocarbons were charged into the reducing furnace).
  • the inventive examples using solid hydrocarbons with a volatile content of 40 mass% or more were able to achieve a greater effect of reducing the amount of natural gas used. They were also advantageous in terms of the effect of reducing CO2 emissions.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Metallurgy (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Manufacture Of Iron (AREA)
PCT/JP2024/040539 2023-12-05 2024-11-14 還元炉の操業方法および還元鉄の製造方法 Pending WO2025121099A1 (ja)

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AU2024393059A AU2024393059A1 (en) 2023-12-05 2024-11-14 Method of operating reduction furnace and method of producing reduced iron
JP2025509014A JPWO2025121099A1 (https=) 2023-12-05 2024-11-14

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4250472B2 (ja) 2003-07-24 2009-04-08 新日本製鐵株式会社 高炉装入原料用還元鉄及び還元性ガスの製造方法、還元鉄の利用方法、並びに還元性ガスの利用方法
JP2017088912A (ja) 2015-11-04 2017-05-25 株式会社神戸製鋼所 還元鉄の製造方法
JP2021175821A (ja) * 2020-04-24 2021-11-04 Ｊｆｅスチール株式会社 高炉の操業方法および高炉附帯設備
WO2022178071A1 (en) * 2021-02-18 2022-08-25 Carbon Technology Holdings, LLC Carbon-negative metallurgical products
JP2023126095A (ja) * 2022-02-28 2023-09-07 株式会社神戸製鋼所 鉄源の製造方法
CN118147383A (zh) * 2022-12-06 2024-06-07 中冶京诚工程技术有限公司 一种气氛可调气基直接还原炼铁系统及方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2022297036B2 (en) * 2021-06-24 2025-04-10 Jfe Steel Corporation Method for producing reduced iron
WO2023162389A1 (ja) * 2022-02-24 2023-08-31 Ｊｆｅスチール株式会社 粉鉄鉱石の還元方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4250472B2 (ja) 2003-07-24 2009-04-08 新日本製鐵株式会社 高炉装入原料用還元鉄及び還元性ガスの製造方法、還元鉄の利用方法、並びに還元性ガスの利用方法
JP2017088912A (ja) 2015-11-04 2017-05-25 株式会社神戸製鋼所 還元鉄の製造方法
JP2021175821A (ja) * 2020-04-24 2021-11-04 Ｊｆｅスチール株式会社 高炉の操業方法および高炉附帯設備
WO2022178071A1 (en) * 2021-02-18 2022-08-25 Carbon Technology Holdings, LLC Carbon-negative metallurgical products
JP2023126095A (ja) * 2022-02-28 2023-09-07 株式会社神戸製鋼所 鉄源の製造方法
CN118147383A (zh) * 2022-12-06 2024-06-07 中冶京诚工程技术有限公司 一种气氛可调气基直接还原炼铁系统及方法

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