JPWO2023171467A5

JPWO2023171467A5 -

Info

Publication number: JPWO2023171467A5
Application number: JP2023533975A
Authority: JP
Filing date: 2023-02-28
Publication date: 2024-02-15
Anticipated expiration: 2043-02-28

Description

ゼロカーボンを志向した製鉄プロセスが考案されている。
非特許文献１には、鉄鋼における二酸化炭素削減の長期目標達成に向けた技術展望がレビューされている。例えば、還元反応で生じた排ガス中のＣＯ_２を分離し、隔離貯蔵し、外部へのＣＯ_２の排出量を削減する方法（ＣＣＳ：ＣａｒｂｏｎｄｉｏｘｉｄｅＣａｐｔｕｒｅａｎｄＳｔｏｒａｇｅ）が紹介されている。また、別の方法では排ガス中のＣＯ_２を分離し、再利用する（ＣＣＵ：ＣａｒｂｏｎｄｉｏｘｉｄｅＣａｐｔｕｒｅａｎｄＵｔｉｌｉｚａｔｉｏｎ）技術が知られており、この技術では、排ガス中のＣＯ_２を用いてＣＨ_４を合成し、合成したＣＨ_４を高炉の羽口から吹込み再度還元反応に使用している。 Steel manufacturing processes aimed at zero carbon have been devised.
Non-Patent Document 1 reviews the technological prospects for achieving the long-term goal of reducing carbon dioxide in steel. For example, a carbon dioxide capture and storage (CCS) method has been introduced in which CO ₂ in the exhaust gas generated in the reduction reaction is separated, isolated and stored, and the amount of CO ₂ released to the outside is reduced. Another known method is carbon dioxide capture and utilization (CCU) technology, which separates and reuses CO ₂ in exhaust gas. In this technology, CH ₄ is synthesized using CO ₂ in exhaust gas. The synthesized CH ₄ is then blown into the blast furnace through the tuyere and used again for the reduction reaction.

なお、本発明に係る溶銑の製造方法は、
（ａ）前記第２工程に代えて、前記炭材内装塊成鉱を１１６０～１４５０℃に加熱して還元および溶融させた後に冷却することで還元鉄を得る還元工程と、前記還元鉄を溶融することで溶銑を製造する溶融工程とを有すること、
（ｂ）前記第３工程において、前記炭素含有ガスは、溶銑の精錬工程で副生される一酸化炭素および二酸化炭素を含むガスをさらに含むこと、
（ｃ）前記第３工程における前記多孔質材料に接触させる前に、前記炭素含有ガスに水素を供給し、８００～１２００℃に加熱して前記炭素含有ガスに含まれる二酸化炭素を一酸化炭素にすること、
（ｄ）前記第３工程における前記加熱後であって前記多孔質材料に接触させる前に、前記炭素含有ガスに含まれる水を除去すること、
（ｅ）下記式（１）（式中で、［Ｈ_２Ｏ]は、改質後の混合ガスに含まれる水分濃度（体積％）を表し、［Ｈ_２]は、改質後の混合ガスに含まれる水素濃度（体積％）を表す。）を満たすように前記炭素含有ガスに含まれる水分と前記炭素含有ガスの改質反応により発生する水分とが除去されること
（ｆ）前記第３工程において、前記多孔質材料は鉄であり、回収される炭素の一部は炭化鉄であること、
（ｇ）前記カーボン含有原料の粒径は１００μｍ以下であること、
（ｈ）前記第１工程において、前記カーボン含有原料はさらにバイオマスを含むこと、
（ｉ）前記鉄含有原料が鉄鉱石であって、前記第１工程の前に該鉄鉱石を、３００℃以上１０００℃以下で熱処理する前処理工程をさらに有すること、
等がより好ましい解決手段になり得る。

In addition, the method for producing hot metal according to the present invention is as follows:
(a) Instead of the second step, a reduction step in which reduced iron is obtained by heating the carbonaceous material-incorporated agglomerate to 1160 to 1450° C. to reduce and melt it, and then cooling it; and a melting process for producing hot metal by
(b) in the third step, the carbon-containing gas further includes a gas containing carbon monoxide and carbon dioxide, which are by-produced in the hot metal refining process;
(c) Before contacting the porous material in the third step, hydrogen is supplied to the carbon-containing gas and heated to 800 to 1200°C to convert carbon dioxide contained in the carbon-containing gas to carbon monoxide. to do,
(d) removing water contained in the carbon-containing gas after the heating in the third step and before contacting the porous material;
(e) The following formula (1) (in the formula, [H ₂ O] represents the water concentration (volume %) contained in the mixed gas after reforming, and [H ₂ ] represents the water concentration (volume %) contained in the mixed gas after reforming. The moisture contained in the carbon-containing gas and the moisture generated by the reforming reaction of the carbon-containing gas are removed so as to satisfy the hydrogen concentration (volume %) contained in the carbon-containing gas. in the step, the porous material is iron, and a portion of the recovered carbon is iron carbide;
(g) the particle size of the carbon-containing raw material is 100 μm or less;
(h) in the first step, the carbon-containing raw material further includes biomass;
(i) the iron-containing raw material is iron ore, further comprising a pretreatment step of heat-treating the iron ore at 300° C. or higher and 1000° C. or lower before the first step;
etc. may be a more preferable solution.

第１工程では、鉄含有原料４とカーボン含有原料６とを混合し、炭材内装塊成鉱２６を製造する。鉄含有原料４としては、粉砕された鉄鉱石が主であり、製鉄所内で発生するダスト等が含まれていてもよい。第２工程では、得られた炭材内装塊成鉱２６を高炉３２に装入し、炉内に送風ガス３４を吹き入れ、還元反応を進行させて溶銑３６を製造する。第３工程では、第２工程の還元反応によって副生される排ガス３８を回収し、排ガス３８に含まれる一酸化炭素を多孔質材料に接触させて固体炭素の析出、回収処理を行う。処理される排ガス３８には、溶銑の精錬処理によって副生される排ガス４０が含まれていることが好ましい。 In the first step, the iron-containing raw material 4 and the carbon-containing raw material 6 are mixed to produce a carbonaceous material-incorporated agglomerate 26. The iron-containing raw material 4 is mainly pulverized iron ore, and may also contain dust generated in a steel mill. In the second step, the obtained carbonaceous agglomerated ore 26 is charged into a blast furnace 32, and blowing gas 34 is blown into the furnace to advance a reduction reaction to produce hot metal 36. In the third step, the exhaust gas 38 by-produced by the reduction reaction in the second step is recovered, and the carbon monoxide contained in the exhaust gas 38 is brought into contact with a porous material to precipitate and recover solid carbon. It is preferable that the exhaust gas 38 to be treated includes exhaust gas 40 that is by-produced by the refining process of hot metal .

以下、各工程を詳細に説明する。
［第１工程］
第１工程は、鉄含有原料とカーボン含有原料とを混合し、炭材内装塊成鉱を製造する工程である。図２に示す例において、まず、貯蔵槽２に貯蔵された鉄含有原料４および排ガス３８に含まれる一酸化炭素から回収された固体炭素を含むカーボン含有原料６と、貯蔵槽８に貯蔵されたセメント粉１０とが、それぞれの貯蔵槽２、８から搬送機１２に所定量切り出される。鉄含有原料４、カーボン含有原料６およびセメント粉１０は、搬送機１２によって混錬機１４に搬送される。搬送された鉄含有原料４、カーボン含有原料６およびセメント粉１０は、適量の水１６と共に、混錬機１４の内部で混合されて混合粉２０となる。その後、混合粉２０は搬送機２２によって造粒機２４に搬送され、適量の水１６と共に、造粒機２４の内部で造粒され、炭材内装塊成鉱２６となる。 Each step will be explained in detail below.
[First step]
The first step is a step of mixing an iron-containing raw material and a carbon-containing raw material to produce a carbonaceous agglomerate ore. In the example shown in FIG. 2, first, the iron-containing raw material 4 stored in the storage tank 2 and the carbon-containing raw material 6 containing solid carbon recovered from carbon monoxide contained in the exhaust gas 38 and the carbon-containing raw material 6 stored in the storage tank 8 A predetermined amount of cement powder 10 is cut out from the respective storage tanks 2 and 8 to a conveyor 12. The iron-containing raw material 4, the carbon-containing raw material 6, and the cement powder 10 are conveyed to a kneader 14 by a conveyor 12. The transported iron-containing raw material 4, carbon-containing raw material 6, and cement powder 10 are mixed together with an appropriate amount of water 16 inside a kneader 14 to form a mixed powder 20. Thereafter, the mixed powder 20 is conveyed to the granulator 24 by the conveyor 22, and is granulated inside the granulator 24 together with an appropriate amount of water 16 to become a carbonaceous material-incorporated agglomerate 26.

［第３工程］
第３工程は、第２工程の還元反応によって副生される排ガス等から固体炭素を析出させて回収する工程である。還元反応によって副生される排ガス３８や、溶銑の精錬処理によって副生される排ガス４０には一酸化炭素、二酸化炭素、水素、水が含まれるが、本実施形態にかかる溶銑の製造方法において、排ガス３８、４０は少なくとも一酸化炭素、二酸化炭素を含んでいればよい。本実施形態の第３工程では、図１に示すように、この排ガス３８、４０を炭化設備１００、ガス改質炉１１０および水分除去装置１２０で処理する。排ガスとして、上記以外に、自動車、ガスタービン、焼却炉、火力発電所、工場から排出される排ガスを用いてもよい。また、排ガス中に存在する各ガス成分の体積割合は、排ガスの原料である燃料の燃焼条件によって調整することができる。例えば、排ガスが高炉ガスである場合には、高炉ガスは、一酸化炭素ガスを２１～２３体積％、二酸化炭素ガスを１９～２２体積％、水素を２～３体積％、窒素ガス５３～５６体積％の体積割合となっているため好ましい。なお、かかる高炉ガスは、高炉に投入されたコークスおよび重油、微粉炭が空気によって部分燃焼し、一酸化炭素と窒素を主成分とする還元性のガスとなり、これが鉄鉱石を還元して生じたものである。 [Third step]
The third step is a step in which solid carbon is precipitated and recovered from exhaust gas etc. produced as a by-product by the reduction reaction in the second step. The exhaust gas 38 produced by the reduction reaction and the exhaust gas 40 produced by the refining process of hot metal contain carbon monoxide, carbon dioxide, hydrogen, and water, but in the method for producing hot metal according to the present embodiment, , the exhaust gases 38 and 40 only need to contain at least carbon monoxide and carbon dioxide. In the third step of this embodiment, as shown in FIG. 1, the exhaust gases 38 and 40 are treated in a carbonization facility 100, a gas reforming furnace 110, and a water removal device 120. In addition to the above, the exhaust gas may be exhaust gas discharged from automobiles, gas turbines, incinerators, thermal power plants, and factories. Further, the volume ratio of each gas component present in the exhaust gas can be adjusted by the combustion conditions of the fuel that is the raw material of the exhaust gas. For example, when the exhaust gas is blast furnace gas, the blast furnace gas contains 21 to 23% by volume of carbon monoxide gas, 19 to 22% by volume of carbon dioxide gas, 2 to 3% by volume of hydrogen, and 53 to 56% of nitrogen gas. The volume ratio is preferably % by volume. Incidentally, such blast furnace gas is produced by the partial combustion of coke, heavy oil, and pulverized coal fed into the blast furnace by air, resulting in a reducing gas whose main components are carbon monoxide and nitrogen, which is produced by reducing iron ore. It is something.

除湿ガスを多孔質材料１０２に接触させ、固体炭素を分離する工程において、除湿ガスと多孔質材料１０２との接触は、５００～８００℃以下の雰囲気下において行うことが好ましい。改質ガスと多孔質材料１０２とを接触させる温度が５００℃以上であれば、一酸化炭素の分解反応が促進されるため好ましく、８００℃以下であれば、一酸化炭素の分解反応により発生する熱エネルギーを有効に活用することができるため好ましい。改質ガスと多孔質材料１０２とを接触させる温度には、直接還元製鉄反応に採用される温度条件である５００～８００℃が含まれる。なお、除湿ガスと多孔質材料との接触は、炭素分離部の系内に備えられた多孔質材料１０２の充填層に当該除湿ガスを通気すればよい。これにより、上記の化学反応式で示される一酸化炭素の分解反応が進行する。一酸化炭素の分解反応が進行することにより、一酸化炭素を構成する固体炭素が多孔質材料１０２の表面に析出する。また、鉄の多孔質材料を用いた場合には、表面に析出した固体炭素の一部または全部が浸炭し、炭化鉄が生成する。 In the step of bringing the dehumidifying gas into contact with the porous material 102 to separate solid carbon, the contact between the dehumidifying gas and the porous material 102 is preferably carried out in an atmosphere of 500 to 800° C. or lower. It is preferable that the temperature at which the reformed gas and the porous material 102 are brought into contact is 500° C. or higher because it promotes the decomposition reaction of carbon monoxide, and if it is 800° C. or lower, carbon monoxide is generated due to the decomposition reaction. This is preferable because thermal energy can be used effectively. The temperature at which the reformed gas and the porous material 102 are brought into contact includes 500 to 800° C., which is the temperature condition employed in the direct reduction ironmaking reaction. Note that the contact between the dehumidifying gas and the porous material may be achieved by passing the dehumidifying gas through a packed bed of the porous material 102 provided within the system of the carbon separation section. As a result, the decomposition reaction of carbon monoxide shown by the above chemical reaction formula proceeds. As the decomposition reaction of carbon monoxide progresses, solid carbon constituting carbon monoxide is deposited on the surface of the porous material 102. Furthermore, when a porous iron material is used, part or all of the solid carbon deposited on the surface is carburized to produce iron carbide.

このように、本実施形態に係る第３工程では、除湿ガスに含まれる一酸化炭素を多孔質材料１０２に接触させることによって、一酸化炭素の分解反応を促進させ、固体炭素を分離し、当該炭素を固体炭素、又は当該炭素を含む炭素固溶体もしくは炭化金属化合物として回収することができる。そして、回収した炭素を用いた炭材内装塊成鉱を原料として溶銑を製造できるので、回収した炭素をプロセス内で循環させることができ、これにより、系外へのＣＯ_２排出量の低減が実現できる。本実施形態における排ガス３８、４０、混合ガス、除湿ガスは、一酸化炭素および二酸化炭素を含む炭素含有ガスの例である。 As described above, in the third step according to the present embodiment, carbon monoxide contained in the dehumidified gas is brought into contact with the porous material 102 to promote the decomposition reaction of carbon monoxide, separate the solid carbon, and Carbon can be recovered as solid carbon, or as a carbon solid solution or metal carbide compound containing the carbon. In addition, hot metal can be produced using carbonaceous agglomerate containing recovered carbon as a raw material, so the recovered carbon can be circulated within the process, thereby reducing _CO2 emissions outside the system. realizable. The exhaust gases 38, 40, mixed gas, and dehumidified gas in this embodiment are examples of carbon-containing gases containing carbon monoxide and carbon dioxide.

２、８貯蔵槽
４鉄含有原料
６カーボン含有原料（固体炭素および／または炭化鉄）
１０セメント粉
１２、２２搬送機
１４混錬機
１６水
２０混合粉
２４造粒機
２６炭材内装塊成鉱
２８他の原料
３０鉄含有塊状原料
３２高炉
３４送風ガス
３６溶銑
３８高炉排ガス
４０精錬処理の排ガス
１００炭化設備（炭素分離部）
１０１反応塔
１０１ａ石英管
１０１ｂサンプルホルダー
１０２多孔質材料（鉄ウィスカー）
１０３アルミナボール
１０４供給管（炭素含有ガス用）
１０５排出ガス管
１１０ガス改質炉（ガス改質部）
１２０水分除去装置（水分除去部）
１３０炭素回収部
１４０炭材内装塊成鉱製造設備 2,8 Storage tank
4 Iron-containing raw material 6 Carbon-containing raw material (solid carbon and/or iron carbide)
10 Cement powder 12, 22 Conveyor 14 Kneading machine 16 Water 20 Mixed powder 24 Granulator 26 Carbonaceous agglomerate 28 Other raw materials 30 Iron-containing lump raw material 32 Blast furnace 34 Blast gas 36 Hot metal 38 Blast furnace exhaust gas 40 Refining treatment Exhaust gas 100% Carbonization equipment (carbon separation section)
101 Reaction tower 101a Quartz tube 101b Sample holder 102 Porous material (iron whisker)
103 Alumina ball 104 Supply pipe (for carbon-containing gas)
105 Exhaust gas pipe 110 Gas reforming furnace (gas reforming section)
120 Moisture removal device (moisture removal section)
130 Carbon recovery department 140 Carbonaceous material-incorporated agglomerate production equipment

Claims

a first step of producing carbonaceous material-incorporated agglomerates from iron-containing raw materials and carbon-containing raw materials;
A second step of blowing oxygen-containing gas into the carbonaceous agglomerate ore to reduce and melt it to produce hot metal, or heating the carbonaceous agglomerate ore to 1160 to 1450°C to reduce and melt it. a second step consisting of a reduction step of obtaining reduced iron by subsequent cooling and a melting step of producing hot metal by melting the reduced iron ;
a third step of recovering carbon by bringing a carbon-containing gas containing carbon monoxide and carbon dioxide by-produced by the reduction into contact with a porous material;
In the first step, the carbon recovered in the third step is used as part or all of the carbon-containing raw material,
Optionally, in the third step, the carbon-containing gas further includes a gas containing carbon monoxide and carbon dioxide that are by-produced in a hot metal refining process,
Furthermore, optionally, in the first step, the carbon-containing raw material further comprises biomass;
Furthermore, optionally, the iron-containing raw material is iron ore, and the method further includes a pretreatment step of heat-treating the iron ore at 300°C or more and 1000°C or less before the first step. Production method.

Before contacting the porous material in the third step, hydrogen is supplied to the carbon-containing gas and heated to 800 to 1200° C. to convert carbon dioxide contained in the carbon-containing gas to carbon monoxide. Item 1. The method for producing hot metal according to item 1.

The method for producing hot metal according to claim 2 , wherein water contained in the carbon-containing gas is removed after the heating in the third step and before contacting the porous material.

The method for producing hot metal according to claim 3 , wherein moisture contained in the carbon-containing gas and moisture generated by a reforming reaction of the carbon-containing gas are removed so as to satisfy the following formula (1).

In the above formula (1), [H ₂ O] represents the water concentration (volume %) contained in the mixed gas after reforming, and [H ₂ ] represents the hydrogen concentration (volume %) contained in the mixed gas after reforming. % by volume).

The method for producing hot metal according to any one of claims 1 to 4 , wherein in the third step, the porous material is iron, and a portion of the recovered carbon is iron carbide.

The method for producing hot metal according to any one of claims 1 to 4 , wherein the carbon-containing raw material has a particle size of 100 μm or less.

The method for producing hot metal according to claim 5, wherein the carbon-containing raw material has a particle size of 100 μm or less.