Molten iron manufacturing equipment and method for manufacturing molten iron

Abstract

Provided are a molten iron manufacturing facility and a method for manufacturing molten iron capable of recycling by-products generated during the reduction of iron ore to produce hydrogen gas. 【Solution means】The molten iron manufacturing facility according to an embodiment of the present invention includes a reduction unit capable of manufacturing reduced iron, a melting unit capable of melting upon receiving the supply of reduced iron, and a reforming unit disposed so as to be able to receive the supply of exhaust gas discharged from the melting unit and by-products discharged from the reduction unit, and capable of generating a hydrogen-containing gas using the exhaust gas and the by-products, and an extraction unit disposed so as to be able to receive the supply of the hydrogen-containing gas generated in the reforming unit and capable of extracting hydrogen gas from the hydrogen-containing gas. The molten iron manufacturing facility further includes a by-product supply line disposed so as to connect the reduction unit and the reforming unit, and an exhaust gas supply line disposed so as to connect the melting unit and the reforming unit. The reduction unit is connected to the by-product supply line and includes a reduction furnace having a reduction space capable of manufacturing reduced iron using a reducing gas. The melting unit is connected to the exhaust gas supply line and includes an electric furnace having a melting space capable of melting reduced iron using electric heat.

Description

Technical Field

[0001] The present invention relates to molten iron manufacturing equipment and a method for manufacturing molten iron, and more particularly, to molten iron manufacturing equipment and a method for manufacturing molten iron for producing reduced iron and melting the produced reduced iron to produce molten iron.

Background Art

[0002] Generally, molten iron, that is, hot metal, is produced through a blast furnace process. The blast furnace process is carried out by processing iron ore and coal into forms suitable for use and charging them into a blast furnace while blowing in hot air. Here, the hot air burns the coal, and the carbon monoxide gas generated at this time causes a reduction reaction that separates oxygen from the iron ore. In addition, the heat of 1,500 °C or higher generated inside the blast furnace causes a melting reaction that melts the iron reduced by the iron ore or carbon monoxide gas, and molten iron is produced. In such a blast furnace process, the reduction reaction and the melting reaction occur simultaneously in the blast furnace by coal and the resulting carbon monoxide gas. However, in such a blast furnace process, there has been a problem that a large amount of carbon dioxide, which causes environmental problems such as global warming, is generated by the reduction reaction between carbon monoxide gas and iron ore.

[0003] In order to solve such problems, efforts have been made to research and develop a hydrogen reduction ironmaking process technology for producing molten iron using hydrogen gas instead of fossil fuels such as coal. Fossil fuels such as coal produce carbon dioxide when reacting with iron ore, but hydrogen gas reacts with iron ore to produce water or water vapor. Therefore, according to the hydrogen reduction ironmaking process, carbon emissions can be significantly reduced in the production of molten iron.

[0004] In order to reduce iron ore and produce molten iron by such a hydrogen reduction ironmaking process, a large amount of hydrogen gas is required. However, since hydrogen gas is a very expensive gas, there is a problem that the process cost increases due to the use of a large amount of hydrogen gas. In addition, when hydrogen gas reacts with iron ore, a large amount of water or steam is generated, and at present, there is an urgent need for a device that can recycle such a large amount of by-products generated in this way.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention provides a molten iron production facility and a method for producing molten iron that can recycle by-products generated during the reduction of iron ore to produce hydrogen gas.

Means for Solving the Problems

[0007] The molten iron production facility of the present invention includes a reduction unit capable of producing reduced iron, a melting unit capable of melting upon receiving the supply of the reduced iron, a reforming unit disposed so as to be capable of receiving the supply of exhaust gas discharged from the melting unit and by-products discharged from the reduction unit, and capable of generating a hydrogen-containing gas using the exhaust gas and the by-products, and an extraction unit disposed so as to be capable of receiving the supply of the hydrogen-containing gas generated in the reforming unit and capable of extracting hydrogen gas from the hydrogen-containing gas.

[0008] The molten iron manufacturing equipment further includes a by-product supply line disposed to connect the reduction unit and the reforming unit, and an exhaust gas supply line disposed to connect the melting unit and the reforming unit. The reduction unit is connected to the by-product supply line and includes a reduction furnace having a reduction space capable of manufacturing reduced iron using reduction gas. The melting unit may be connected to the exhaust gas supply line and include an electric furnace having a melting space capable of melting reduced iron using electric heat.

[0009] The reforming unit may be connected to the exhaust gas supply line and the by-product supply line so as to be capable of receiving the supply of the exhaust gas and the by-product, and include a reactor having a reaction space capable of reacting the exhaust gas and the by-product to generate a hydrogen-containing gas.

[0010] The reforming unit may be connected to the by-product supply line and include a purifier capable of extracting a reaction object from the by-product, and a reactor connected to the exhaust gas supply line and the purifier so as to be capable of receiving the supply of the exhaust gas and the reaction object, and having a reaction space capable of reacting the exhaust gas and the reaction object to generate a hydrogen-containing gas.

[0011] The purifier may be connected to the by-product supply line and include a separator capable of separating a reaction object from the by-product in a liquid state, and a heater connected to the separator, heating the reaction object in a liquid state to vaporize it, and connected to the reactor so as to be capable of supplying the vaporized reaction object to the reactor.

[0012] The heater may be disposed to intersect the exhaust gas supply line and include a heat exchanger capable of transferring the heat of the exhaust gas to the reaction object in a liquid state.

[0013] The molten iron manufacturing equipment may further include a purge gas supply line connected to the reduction furnace and capable of supplying purge gas to the reduction space. The heater may be connected to the purge gas supply line and may be capable of supplying the vaporized reaction object to the purge gas supply line.

[0014] The extraction unit may include a first extractor connected to the reactor and capable of extracting hydrogen gas from the hydrogen-containing gas generated in the reactor, and a second extractor connected to the separator and capable of extracting hydrogen gas from the residual gas discharged from the separator.

[0015] The molten iron production facility may further include a raw material supply unit having a storage space capable of storing raw materials and arranged to supply the raw materials stored in the storage space to the reduction space, and a branch line branched from the exhaust gas supply line and capable of supplying a part of the exhaust gas discharged from the electric furnace to the raw material supply unit.

[0016] The branch line may be connected to the raw material supply unit so as to directly supply exhaust gas to the storage space, or so as to transfer the heat of the exhaust gas to the air supplied to the storage space.

[0017] The molten iron production facility may further include a reducing gas supply line connected to the reduction furnace and capable of supplying reducing gas to the reduction space, and the extraction unit may be connected to the reducing gas supply line and may be capable of supplying hydrogen gas to the reducing gas supply line.

[0018] In addition, the method for producing molten iron according to the present invention includes a process of producing reduced iron, a process of collecting by-products generated in the process of producing the reduced iron, a process of melting the reduced iron to produce a melt, a process of collecting exhaust gas discharged in the process of producing the melt, a process of producing a hydrogen-containing gas using the collected by-products and exhaust gas, and a process of extracting hydrogen gas from the hydrogen-containing gas.

[0019] The process of producing the reduced iron may include a process of preheating the raw materials using the exhaust gas and a process of reducing the preheated raw materials by reacting them with the reducing gas.

[0020] The process of preheating the raw material may include a process of spraying the exhaust gas onto the raw material or a process of spraying the air heated by receiving the heat transfer of the exhaust gas onto the raw material.

[0021] The raw material may include powdered iron ore having a particle size exceeding 0 mm and not exceeding 8 mm.

[0022] The process of producing the hydrogen-containing gas may include a process of directly reacting the collected by-products with the exhaust gas.

[0023] The process of producing the hydrogen-containing gas may include a process of extracting a reaction object from the collected by-products and a process of reacting the extracted reaction object with the exhaust gas.

[0024] The process of extracting the reaction object may include a process of spraying a treatment liquid onto the collected by-products to separate the reaction object in a liquid state and a process of heating and vaporizing the reaction object in a liquid state.

[0025] The process of vaporizing may include a process of heating the reaction object in a liquid state by the heat of the exhaust gas.

[0026] The process of producing the reduced iron includes a process of supplying a purge gas to a reduction space for producing the reduced iron, and the process of supplying the purge gas may include a process of using a part of the vaporized reaction object as the purge gas supplied to the reduction space.

[0027] The method for producing molten iron may further include a process of collecting the residual gas discharged in the process of separating the reaction object in a liquid state and a process of extracting hydrogen gas from the residual gas.

[0028] The method for producing molten iron may further include a process of supplying the extracted hydrogen gas during the process of producing the reduced iron.

[0029] The reaction target contains water vapor, and the exhaust gas may contain carbon monoxide gas.

Advantages of the Invention

[0030] According to an embodiment of the present invention, by reacting a by-product discharged during the production of reduced iron with an exhaust gas discharged during the melting of reduced iron to produce hydrogen gas, the by-products generated during the process can be effectively recycled.

[0031] In addition, by reusing the produced hydrogen gas as a reducing gas for reducing the raw material, the amount of hydrogen gas used can be reduced, and the resources and costs involved in the process can be minimized.

[0032] Moreover, by using the sensible heat of the exhaust gas having a high temperature for preheating the raw material and producing hydrogen gas, energy can be efficiently recovered.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0034] Hereinafter, embodiments of the present invention will be described in more detail based on the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and can be embodied in various different forms. The embodiments of the present invention are merely provided to make the disclosure of the present invention complete and to fully inform those with ordinary knowledge of the scope of the invention. For the purpose of describing the present invention in detail, the drawings may be shown exaggerated, and in the drawings, the same reference numerals indicate the same components.

[0035] FIG. 1 is a diagram schematically showing the molten iron production facility of the present invention. FIG. 2 is a diagram exemplarily showing a reduction furnace for producing reduced iron and an electric furnace for melting the produced reduced iron. FIG. 3 is a diagram showing a state where raw materials are preheated using exhaust gas in the raw material supply section. Further, FIG. 4 is a diagram schematically showing the molten iron production facility according to another embodiment of the present invention, and FIG. 5 is a diagram showing a state where a separator separates a reaction target from by-products in a liquid state. In the drawings, the arrows indicated by dotted lines show the flow of raw materials and reduced iron, and the arrows indicated by solid lines show the flow of by-products and gas.

[0036] As shown in FIGS. 1 to 5, the molten iron production facility of the present invention includes a reduction section 500 capable of producing reduced iron, a melting section 600 capable of melting upon receiving the supply of the reduced iron, a reforming section 700 arranged to be able to receive the supply of exhaust gas discharged from the melting section 600 and by-products discharged from the reduction section 500 and capable of generating a hydrogen-containing gas using the exhaust gas and by-products, and an extraction section 800 arranged to be able to receive the supply of the hydrogen-containing gas generated in the reforming section 700 and capable of extracting hydrogen gas from the hydrogen-containing gas. Further, the molten iron production facility of the present invention may further include a raw material supply section 100 arranged to be able to supply raw materials to the reduction section 500 and a reducing gas supply section 200 arranged to be able to supply reducing gas to the reduction section 500.

[0037] The raw material supply unit 100 is arranged so as to be able to supply raw materials to the reduction unit 500. Here, the raw materials may include iron ore, and the iron ore may include fine iron ore having a particle size exceeding 0 mm and not exceeding 8 mm, that is, powdered iron ore. The raw material supply unit 100 may include a storage device 110 having a storage space capable of storing raw materials. The raw materials may be stored in the storage space of the storage device 110 for a long time, or may be temporarily stored before being supplied to the reduction unit 500. Such a storage device 110 may include, for example, a hopper.

[0038] In the storage space of the storage device 110, the raw materials can be preheated, and the raw materials preheated in the storage space can be supplied to the reduction unit 500. At this time, the storage device 110 can preheat the raw materials by receiving a part of the exhaust gas discharged from the melting unit 600. For this purpose, the molten iron production facility of the present invention may further include a branch line DL branched from the exhaust gas supply line EL and capable of supplying a part of the exhaust gas discharged from the melting unit 600 to the storage device 110. The content of preheating the raw materials using the exhaust gas supplied through the branch line DL will be described later in connection with FIG. 3.

[0039] The reducing gas supply unit 200 is arranged so as to store the reducing gas and be able to supply the reducing gas to the reduction unit 500. Here, the reducing gas may include hydrogen gas, and the hydrogen gas may be contained in the total reducing gas at a ratio of 80 to 100%. The hydrogen gas stored in the reducing gas supply unit 200 can be produced by electrolyzing water, but the present invention is not limited thereto, and can be produced by various methods such as decomposing ammonia gas or causing a chemical reaction of natural gas to produce hydrogen gas. For example, ammonia gas can be decomposed into hydrogen gas and nitrogen gas at high temperature, and the decomposed hydrogen gas can be used as the reducing gas, and the nitrogen gas can be used as the purge gas described later.

[0040] The reducing gas supply unit 200 can supply a reducing gas to the reduction unit 500 via reducing gas supply lines RL1 and RL2 that connect the reducing gas supply unit 200 and the reduction unit 500 to each other. At this time, the amount of the reducing gas supplied by the reducing gas supply unit 200 to the reduction unit 500 may be two times or more the amount required to completely reduce all the raw materials supplied to the reduction unit 500. In order to improve the reaction efficiency between the raw material and the reducing gas, the amount of the reducing gas can be controlled, for example, within a range of two times or more and three times or less the amount required to completely reduce all the raw materials supplied to the reduction unit 500.

[0041] A heating unit 300 for heating the reducing gas supplied from the reducing gas supply unit 200 to the reduction unit 500 may be disposed in the reducing gas supply lines RL1 and RL2. In the reduction unit 500, a raw material containing iron ore reacts with a reducing gas containing hydrogen gas to reduce the iron ore. Since such a reaction between iron ore and hydrogen gas is a strong endothermic reaction, the hydrogen gas supplied to the reduction unit 500 can improve the reaction efficiency when it is heated to a temperature of 800°C or higher, more preferably 850°C or higher, and then supplied. For this reason, the heating unit 300 is connected to the reducing gas supply unit 200 by the first reducing gas supply line RL1 and to the reduction unit 500 by the second reducing gas supply line RL2, and can heat the low-temperature hydrogen gas supplied via the first reducing gas supply line RL1 to a temperature of 800 to 1200°C and supply it to the reduction unit 500 via the second reducing gas supply line RL2. Since various structures for directly or indirectly heating the reducing gas are applicable to the heating unit 300, a detailed description thereof is omitted.

[0042] The molten iron production facility of the present invention may further include a purge gas supply unit 400 that stores purge gas and is arranged to supply the purge gas to the reduction unit 500. The reduction unit 500 has a reduction space capable of producing reduced iron, and the reduction space needs to be purged for maintenance between processes. Also, it may be necessary to supply purge gas during the process. For example, when using powdered iron ore as a raw material, the purge gas can be supplied to increase the fluidity of the powdered iron ore in order to prevent the powdered iron ore from sticking in the reduction space. Therefore, the purge gas supply unit 400 can supply the purge gas to the reduction space via a purge gas supply line PL that connects the purge gas supply unit 400 and the reduction unit 500 to each other, and as the purge gas, an inert gas such as nitrogen can be used.

[0043] The reduction unit 500 can produce reduced iron by reducing the raw material. That is, the reduction unit 500 receives the supply of iron ore as the raw material from the raw material supply unit 100 and the supply of the reducing gas from the reducing gas supply unit 200, and can produce reduced iron by reacting the iron ore with the reducing gas. Such a reduction unit 500 may include a reduction furnace having a reduction space capable of producing reduced iron using the reducing gas. Such a reduction furnace may include fluidized reduction furnaces 510, 520, 530, 540 that produce reduced iron while flowing the raw material. The fluidized reduction furnaces 510, 520, 530, 540 may be provided individually, but in order to effectively reduce low-grade iron ore or powdered iron ore with a low iron content, as shown in FIG. 2, a plurality of fluidized reduction furnaces 510, 520, 530, 540 may be connected to each other to produce reduced iron while sequentially moving the raw material. At this time, there is no limit to the number of the fluidized reduction furnaces 510, 520, 530, 540, but in order to sufficiently reduce the raw material, as shown in FIG. 2, the reduction unit 500 may be composed of four reduction furnaces including a first fluidized reduction furnace 510, a second fluidized reduction furnace 520, a third fluidized reduction furnace 530, and a fourth fluidized reduction furnace 540. At this time, the raw material supply unit 100 can supply the raw material to the first fluidized reduction furnace 510, and the reducing gas supply unit 200 can supply the reducing gas to the fourth fluidized reduction furnace 540. The raw material supplied to the first fluidized reduction furnace 510 can be produced as reduced iron by being reduced while moving through the second fluidized reduction furnace 520, the third fluidized reduction furnace 530, and the fourth fluidized reduction furnace 540 in this order.

[0044] The reduced iron produced in the reduction unit 500 is supplied to the melting unit 600. As shown in FIG. 2, the reduced iron produced through the first fluidized reduction furnace 510, the second fluidized reduction furnace 520, the third fluidized reduction furnace 530, and the fourth fluidized reduction furnace 540 is discharged from the fourth fluidized reduction furnace 540 and supplied to the melting unit 600. Here, as described above, preheated raw materials and a reducing gas at 800°C or higher are supplied to the reduction space to produce reduced iron. Therefore, the reduced iron produced in the reduction unit 500 is discharged in a high-temperature state of, for example, 600 to 800°C, even considering heat loss. In this way, the reduced iron discharged in a high-temperature state can be directly supplied to the melting unit 600 without passing through a separate cooling device. That is, the reduced iron or fine powder reduced iron produced by reducing iron ore having a particle size exceeding 8 mm or fine iron ore having a particle size exceeding 0 mm and not exceeding 8 mm can be directly supplied to the melting unit 600. However, needless to say, the reduced iron or fine powder reduced iron may be supplied to the melting unit 600 after being agglomerated in a hot state in a separate forming device.

[0045] On the other hand, a large amount of by-products are discharged from the reduction unit 500 in addition to reduced iron. The by-products discharged from the reduction unit 500 may contain steam. As described above, in the reduction unit 500, iron ore and hydrogen gas react to produce reduced iron. At this time, the oxygen component of the iron ore and the hydrogen component of the hydrogen gas react, and a large amount of steam is generated in the reduction space. The generated steam is discharged from the reduction unit 500 as a by-product. Further, the by-products discharged from the reduction unit 500 may contain hydrogen gas and nitrogen gas. As described above, since the reducing gas is supplied in a range of 2 times or more and 3 times or less the amount required to reduce all the raw materials supplied to the reduction unit 500, the remaining hydrogen gas that does not react with the raw materials is discharged from the reduction unit 500 as a by-product. In addition, as described above, purge gas, for example, nitrogen gas, can be supplied to the reduction unit 500 for various reasons. In this way, the nitrogen gas supplied for purging is discharged from the reduction unit 500 as a by-product. In addition to this, dust generated in the reduction unit 500 can be included in the by-products and discharged. The by-products move along the flow of the reducing gas in the reduction unit 500 and are discharged from the first fluidized reduction furnace 510. The discharged by-products can be supplied to the reforming unit 700 via the by-product supply line BL connected to the reduction unit 500.

[0046] The melting unit 600 can receive the supply of reduced iron and melt it in various ways. For example, the melting unit 600 can receive the supply of fine powder or agglomerated reduced iron from the reduction unit 500 and heat and melt it. In addition to reduced iron, the melting unit 600 can also receive the supply of iron scraps or the like and melt the reduced iron and iron scraps together. Such a melting unit 600 may include electric furnaces 610 and 620 having a melting space capable of melting reduced iron using electric heat. Such electric furnaces 610 and 620 may include an electric furnace body 610 having a melting space and electrode rods 620 at least a part of which is disposed in the melting space so as to be capable of generating electric heat. When reduced iron is charged into the melting space of the electric furnaces 610 and 620, electric power is applied to the electrode rods 620 to melt the reduced iron.

[0047] However, reduced iron has a high melting point of about 1,500°C or higher and is difficult to melt. Therefore, in the melting section 600, a carburizer having a carbon component is introduced to change at least some of the iron particles of the reduced iron into a cementite (Fe3C) phase having a melting point of about 1,200°C or lower. In addition, at least a part of the raw material that has not been reduced from the reduction section 500, that is, partially reduced reduced iron or iron ore, can be supplied to the melting section 600. In this way, the raw material that has not been fully reduced contains an oxygen component, and in the melting space, the oxygen component reacts with the carbon component of the carburizer. Therefore, in the melting section 600, exhaust gas containing carbon monoxide gas, that is, exhaust gas having a high carbon monoxide concentration (CO-rich), is discharged while melting the reduced iron. Thus, the exhaust gas discharged from the melting section 600 is discharged at a high temperature of about 1,200°C or higher.

[0048] The molten iron production facility of the present invention can produce hydrogen gas by utilizing the by-products discharged from the reduction section 500 and the high-temperature exhaust gas containing carbon monoxide gas discharged from the melting section 600. Such hydrogen gas can be produced by the reforming section 700 generating a hydrogen-containing gas using the exhaust gas and the by-products, and the extraction section 800 extracting hydrogen gas from the generated hydrogen-containing gas. For this purpose, the molten iron production facility of the present invention may further include a by-product supply line BL arranged to connect the reduction section 500 and the reforming section 700 and an exhaust gas supply line EL arranged to connect the melting section 600 and the reforming section 700.

[0049] As shown in FIG. 1, the molten iron manufacturing facility of the present invention directly reacts the by-products discharged from the reduction unit 500 with the exhaust gas discharged from the melting unit 600 to produce hydrogen gas. That is, in the present invention, hydrogen gas is produced by directly reacting the by-products discharged from the reduction unit 500 with the exhaust gas without separating a specific substance from the by-products. For this purpose, the reforming unit 700 may be connected to the exhaust gas supply line EL so as to receive the supply of the exhaust gas, and connected to the by-product supply line BL so as to receive the supply of the by-products, and include reactors 730 and 740 having a reaction space capable of reacting the exhaust gas and the by-products to generate a hydrogen-containing gas. Further, the extraction unit 800 may be connected to the reforming unit 700 and extract hydrogen gas from the hydrogen-containing gas supplied from the reforming unit 700.

[0050] As described above, the by-products discharged from the reduction unit 500 may contain water vapor, hydrogen gas, nitrogen gas, dust, and the like. Here, the dust may be removed from the by-products before being supplied to the reforming unit 700 or from within the reforming unit 700. Further, the exhaust gas discharged from the melting unit 600 may contain a large amount of carbon monoxide gas. The reforming unit 700 reacts the by-products containing water vapor, hydrogen gas, nitrogen gas, etc. with the exhaust gas containing carbon monoxide gas. At this time, the water vapor contained in the by-products and the carbon monoxide gas contained in the exhaust gas are reformed into hydrogen gas and carbon dioxide gas by an aqueous gas shift reaction (WGSR) according to the following reaction formula in the presence of a catalyst such as chromium oxide (Cr2O3), aluminum oxide (Al2O3), or copper oxide (CuO).

[0051] [Reaction formula] TIFF2025525173000002.tif12128

[0052] Thus, since water vapor and carbon monoxide gas react with each other and are reformed into carbon dioxide and hydrogen gas, a hydrogen-containing gas, that is, a gas containing hydrogen gas, nitrogen gas, and carbon dioxide gas, can be generated in the reforming unit 700.

[0053] Here, the reforming unit 700 may include reactors 730 and 740 having a reaction space capable of reacting exhaust gas and by-products to produce a hydrogen-containing gas. At this time, the reactors 730 and 740 may be disposed individually, but as shown in FIG. 1, a plurality of reactors 730 and 740 may be connected in series. That is, the reforming unit 700 is connected to an exhaust gas supply line EL and a by-product supply line BL and is capable of primarily reacting exhaust gas and by-products, and is connected to the first reactor 730. The reforming unit 700 may include a second reactor 740 that receives the supply of hydrogen-containing gas, residual exhaust gas, and residual by-products from the first reactor 730 and is capable of secondarily reacting the residual exhaust gas and the residual by-products. The water gas shift reaction has a high conversion rate at high temperatures but a low equilibrium conversion rate, and has a high equilibrium conversion rate at low temperatures but a low conversion rate. For this reason, the reforming unit 700 can maximize the reaction efficiency by primarily and rapidly reacting exhaust gas and by-products through the first reactor 730 in a relatively high-temperature atmosphere, and then stably reacting exhaust gas and by-products through the second reactor 740 in a relatively low-temperature atmosphere. In the figure, a configuration in which two reactors including the first reactor 730 and the second reactor 740 are connected in series is shown. However, it goes without saying that the reactor can be configured with three or more reactors, such as including a high-temperature reactor that reacts in a high-temperature atmosphere, a medium-temperature reactor that reacts in a medium-temperature atmosphere, and a low-temperature reactor that reacts in a low-temperature atmosphere. When composed of three reactors, the high-temperature reactor can react in a high-temperature atmosphere of 350 to 550 °C, the medium-temperature reactor can react in a medium-temperature atmosphere of 250 to 350 °C, and the low-temperature reactor can react in a low-temperature atmosphere of 200 to 250 °C.

[0054] The reforming unit 700 is connected to the extraction unit 800 via a hydrogen-containing gas supply line ML, and the extraction unit 800 can receive the supply of the hydrogen-containing gas generated in the reforming unit 700 and extract hydrogen gas from the hydrogen-containing gas. For example, the extraction unit 800 is connected to the second reactor 740 by a hydrogen-containing gas supply line ML and can receive the supply of the hydrogen-containing gas from the second reactor 740 and extract hydrogen gas. Such an extraction unit 800 can extract hydrogen gas from the hydrogen-containing gas by a pressure swing adsorption (PSA) method. That is, the pressure swing adsorption method extracts gas using the adsorption selectivity of each component for the adsorbent, and the extraction unit 800 can use a carbon molecular sieve capable of adsorbing hydrogen components as the adsorbent in order to extract hydrogen gas from the hydrogen-containing gas containing various gases in addition to hydrogen gas. At this time, the hydrogen component adsorbed on the adsorbent can be desorbed and extracted as hydrogen gas, and the extraction unit 800 can extract hydrogen gas from the hydrogen-containing gas by repeating the adsorption and desorption of the hydrogen component in this way.

[0055] The hydrogen gas extracted in the extraction unit 800 can be used for various purposes. For example, the reduction unit 500 can reduce the raw material, that is, iron ore, using the extracted hydrogen gas. The hydrogen gas is used in a large amount that is more than twice the amount required to reduce all the raw materials supplied to the reduction unit 500, and since it is a very expensive gas, in order to save costs through resource recycling, the hydrogen gas extracted in the extraction unit 800 can be reused as a reducing gas for reducing iron ore. For this purpose, a hydrogen gas supply line HL is connected to the extraction unit 800, and the hydrogen gas supply line HL is connected to the first reducing gas supply line RL1, and the extraction unit 800 can supply hydrogen gas to the first reducing gas supply line RL1, and the extracted hydrogen gas can be supplied to the reduction unit 500 along the hydrogen gas supply line HL, the first reducing gas supply line RL1, and the second reducing gas supply line RL2 and used for reducing iron ore.

[0056] As described above, the exhaust gas discharged from the melting section 600 can react with the by-products discharged from the reduction section 500 to be produced as hydrogen gas. However, as described above, the exhaust gas discharged from the melting section 600 is discharged in a high-temperature state of about 1,200°C or higher. Therefore, in the embodiment of the present invention, the heat energy of the exhaust gas can be utilized to preheat the raw material.

[0057] As shown in FIG. 3, the raw material supply section 100 may include a reservoir 110, and the reservoir 110 has a storage space capable of storing the raw material. In the storage space of the reservoir 110, the raw material can be preheated, and the raw material preheated in the storage space can be supplied to the reduction section 500. For this purpose, the raw material supply section 100 may further include a preheating gas supply device 120 arranged so as to be able to supply preheating gas to the storage space of the reservoir 110. At this time, as shown in FIG. 3(a), the preheating gas supply device 120 is connected to the branch line DL and can directly supply the high-temperature exhaust gas E having a temperature of about 1,200°C or higher to the storage space to preheat the raw material. Further, as shown in FIG. 3(b), the preheating gas supply device 120 may be arranged so as to heat the external air A supplied to the storage space with the heat of the exhaust gas having a temperature of 1,200°C or higher and supply the heated air to the storage space to preheat the raw material. For this purpose, the preheating gas supply device 120 may be arranged so as to intersect the branch line DL, whereby the sensible heat of the exhaust gas passing through the branch line DL can reach the external air A.

[0058] Hereinafter, with reference to FIG. 4, a molten iron manufacturing facility according to another embodiment of the present invention will be described. The molten iron manufacturing facility of the present invention directly reacts the by-products discharged from the reduction unit 500 with the exhaust gas discharged from the melting unit 600 to produce hydrogen gas, whereas the molten iron manufacturing facility according to another embodiment separates the reaction target from the by-products discharged from the reduction unit 500 and reacts this with the exhaust gas to produce hydrogen gas, which is different in this respect. Therefore, the molten iron manufacturing facility according to another embodiment of the present invention will be described with emphasis on such differences, and the description of the parts applicable in the same manner as the molten iron manufacturing facility described above will be omitted.

[0059] The reforming unit 700 according to another embodiment of the present invention is connected to the by-product supply line BL, and includes purifiers 710, 720 capable of extracting a reaction target from the by-products supplied through the by-product supply line BL, and exhaust gas supply lines EL1, EL2 connected to the purifiers 710, 720 so as to be able to receive the supply of the exhaust gas and the reaction target respectively, and reactors 730, 740 having a reaction space capable of reacting the exhaust gas with the reaction target to generate a hydrogen-containing gas.

[0060] At this time, the purifiers 710, 720 may include a separator 710 connected to the by-product supply line BL and capable of separating the reaction target from the by-products supplied through the by-product supply line BL in a liquid state, and a heater 720 connected to the separator 710 and capable of heating and vaporizing the reaction target in a liquid state supplied from the separator 710. At this time, the heater 720 may be arranged so as to cross the exhaust gas supply lines EL1, EL2, that is, above the exhaust gas supply lines EL1, EL2. For example, the heater 720 may be connected to the melting unit 600 and the first exhaust gas supply line EL1, and the reaction target vaporized in the heater 720 can be supplied to the reactors 730, 740 through the second exhaust gas supply line EL2.

[0061] As described above, the by-products discharged from the reduction unit 500 may include water vapor, hydrogen gas, nitrogen gas, dust, and the like. Here, as shown in FIG. 5, the separator 710 can collect dust by spraying water on the by-products. The collected dust can be discharged to the outside of the separator 710 through an outlet (not shown) of the separator 710 and removed. At this time, the water vapor in the by-products can be condensed by the sprayed water and mixed with the sprayed water to be separated from the by-products in a liquid state, that is, water. The separated water is supplied to the heater 720 along the water supply line WL connecting the separator 710 and the heater 720. On the other hand, a residual gas containing hydrogen gas and nitrogen gas excluding water vapor and dust can be discharged from the separator 710, and such a residual gas can move along the residual gas supply line ML2 and be supplied to a second extractor 820 described later.

[0062] The heater 720 can receive the supply of the reaction object in a liquid state, that is, water, from the separator 710 through the water supply line WL, and heat the supplied water to vaporize it into water vapor. A variety of structures for heating water to vaporize it into water vapor can be applied to such a heater 720. However, as described above, the exhaust gas discharged from the dissolution unit 600 is discharged in a high-temperature state of about 1,200 °C or higher. Therefore, in the embodiment of the present invention, a heat exchanger can be used as the heater 720 to utilize the thermal energy of the exhaust gas to vaporize water into water vapor. Such a heat exchanger can be connected to the first exhaust gas supply line EL1 to receive the supply of exhaust gas, and transfer the heat of the exhaust gas having a temperature of 1,200 °C or higher to the water supplied from the separator 710 through the water supply line WL to vaporize the water into water vapor. Thus, the water vapor produced in the heat exchanger can be transmitted to the reactor along the first water vapor supply line SL1 in whole or in part.

[0063] When a part of the steam produced in the heater 720 is transmitted to the reactors 730 and 740 along the first steam supply line SL1, another part of the steam produced in the heater 720 can be supplied to the reduction unit 500 as a purge gas along the second steam supply line SL2. That is, the steam is a reaction product produced by the reaction of the iron ore as a raw material and the hydrogen gas in the reducing gas, and since its reactivity with the iron ore and the reducing gas is low, it can be supplied to the reduction unit 500 as a purge gas. Thus, when the steam is supplied to the reduction unit 500 as a purge gas, the heat of the steam can be utilized for the reduction reaction, and the energy required for the reduction reaction can be reduced. In order to supply the steam to the reduction unit 500 as a purge gas, the second steam supply line SL2 may be connected to the purge gas supply line PL. Needless to say, alternatively, the second steam supply line SL2 may be directly connected to the reduction unit 500 so that the steam and the purge gas are supplied to the reduction unit 500 through different paths from each other.

[0064] The reactors 730 and 740 react the exhaust gas supplied via the second exhaust gas supply line EL2 through the heater 720 with the vaporized object to be reacted, i.e., water vapor, supplied from the heater 720 via the first water vapor supply line SL1 in the reaction space to generate a hydrogen-containing gas. In this way, when water vapor is extracted and supplied to the reactor and reacted with the exhaust gas, the reaction efficiency can be further improved. That is, the reactor reforms carbon monoxide gas contained in water vapor and the exhaust gas into hydrogen gas and carbon dioxide gas in the presence of a catalyst by the above-described water gas shift reaction. However, if water vapor is extracted and supplied to the reactor, since the concentration of water vapor is high compared to the case where by-products containing various gases other than water vapor are directly reacted with the carbon monoxide component contained in the exhaust gas, the reaction rate can be further improved. On the other hand, the reactor may include a first reactor 730 connected to the second exhaust gas supply line EL2 and the heater 720 and capable of primarily reacting the exhaust gas and water vapor, and a second reactor 740 connected to the first reactor 730 and capable of secondarily reacting by receiving the supply of residual exhaust gas and residual water vapor from the first reactor 730. Alternatively, as described above, it can be configured with three or more reactors, such as a high-temperature reactor that performs the reaction in a high-temperature atmosphere, a medium-temperature reactor that performs the reaction in a medium-temperature atmosphere, and a low-temperature reactor that performs the reaction in a low-temperature atmosphere. Therefore, duplicate explanations are omitted.

[0065] The extraction unit 800 is connected to the reactor and can extract hydrogen gas by receiving the supply of the hydrogen-containing gas containing hydrogen gas and carbon dioxide gas generated in the reactor. As described above, such an extraction unit 800 may adsorb the hydrogen component and desorb the adsorbed hydrogen component to extract hydrogen gas, or alternatively, may adsorb the carbon dioxide component and collect the hydrogen gas that cannot be adsorbed and is discharged to extract hydrogen gas.

[0066] At this time, the extraction unit 800 may include a first extractor 810 and a second extractor 820. Here, the first extractor 810 is connected to the reactors 730 and 740 via the hydrogen-containing gas supply line ML1, and can extract hydrogen gas from the hydrogen-containing gas supplied via the reactors 730 and 740. On the other hand, the second extractor 820 is connected to the separator 710 via the residual gas supply line ML2, and can extract hydrogen gas from the residual gas discharged from the separator 710. The separator 710 collects dust in the by-products and separates water vapor in the by-products. From the separator 710, a residual gas containing hydrogen gas and nitrogen gas excluding such water vapor and dust is discharged. At this time, the second extractor 820 can extract the hydrogen gas contained in the residual gas. For this purpose, the second extractor 820 can adsorb the hydrogen component in the residual gas containing hydrogen gas and nitrogen gas, and desorb the adsorbed hydrogen component to extract hydrogen gas. At this time, the first extractor 810 and the second extractor 820 are respectively connected to the first reduction gas supply line RL1 by the first hydrogen gas supply line HL1 and the second hydrogen gas supply line HL2, and can supply hydrogen gas to the reduction gas supply line RL. The hydrogen gas extracted by the first extractor 810 and the second extractor 820 is supplied to the reduction unit 500 along the first reduction gas supply line RL1 and the second reduction gas supply line RL2 and can be used for the reduction of iron ore.

[0067] The molten iron production facility according to the embodiment of the present invention can produce hydrogen gas by moving by-products and gas along the above-described respective pipes. The movement of the by-products and gas can be controlled using valves (not shown) disposed in the pipes. Needless to say, such valves can be disposed at various positions to control the flow rate and flow velocity of the by-products and gas moving along each pipe.

[0068] Hereinafter, a method for producing molten iron according to an embodiment of the present invention will be described. The method for producing molten iron of the present invention may be a method for producing molten iron using the above-described molten iron production facility. Therefore, the content described above regarding the molten iron production facility is applicable as it is, and the description of overlapping content will be omitted.

[0069] FIG. 6 is a diagram schematically showing a method for producing molten iron according to an embodiment of the present invention.

[0070] As shown in FIG. 6, the method for producing molten iron of the present invention includes a process (S100) of producing reduced iron, a process (S200) of collecting by-products generated in the process of producing the reduced iron, a process (S300) of melting the reduced iron to produce a melt, a process (S400) of collecting exhaust gas discharged in the process of producing the melt, a process (S500) of producing a hydrogen-containing gas using the collected by-products and exhaust gas, and a process (S600) of extracting hydrogen gas from the hydrogen-containing gas. Here, the process (S100) of producing reduced iron and the process (S200) of collecting by-products generated in the process of producing the reduced iron can be performed simultaneously, and the process (S300) of melting the reduced iron to produce a melt and the process (S400) of collecting exhaust gas discharged in the process of producing the melt can also be performed simultaneously. Also, each process can be continuously performed to produce molten iron, and it goes without saying that there is a possibility that it does not correspond to a time-series relationship in which another process is performed after any one process is performed and completed.

[0071] The process (S100) of producing reduced iron is performed by supplying a raw material and a reducing gas to a reduction unit 500. That is, the process (S100) of producing reduced iron may include a process of supplying a raw material to the reduction unit 500, a process of supplying a reducing gas to the reduction unit 500, and a process of reacting the raw material with the reducing gas to reduce it.

[0072] The process of supplying raw materials is carried out by the raw material supply unit 100 arranged to be able to supply raw materials to the reduction unit 500 supplying raw materials to the reduction unit 500. Here, the raw materials may include iron ore, and the iron ore may include fine powder iron ore having a particle size exceeding 0 mm and not exceeding 8 mm, that is, powdered iron ore. On the other hand, the process of supplying raw materials may include the process of preheating the raw materials. In the embodiment of the present invention, by supplying and reducing the preheated raw materials, that is, iron ore, the energy required for reduction can be suppressed as much as possible.

[0073] The process of supplying reducing gas is carried out by the reducing gas supply unit 200 supplying reducing gas to the reduction unit 500. Here, the reducing gas may include hydrogen gas, and the hydrogen gas may be contained in the total reducing gas at a ratio of 80 to 100%. The process of supplying reducing gas is carried out by the reducing gas supply unit 200 supplying reducing gas to the reduction unit 500 through the reducing gas supply lines RL1 and RL2 connecting the reducing gas supply unit 200 and the reduction unit 500 to each other. At this time, the amount of the reducing gas supplied to the reduction unit 500 in the process of supplying the reducing gas can be controlled within a range of not less than 2 times and not more than 3 times the required amount for reducing all the raw materials supplied to the reduction unit 500.

[0074] In the process of supplying the reducing gas, the reducing gas can be heated to a temperature of 800 to 1200 ° C and supplied to the reduction unit 500. When hydrogen gas is used as the reducing gas, the iron ore supplied to the reduction unit 500 reacts with the hydrogen gas to produce reduced iron. Since such a reaction between the iron ore and the hydrogen gas is a strong endothermic reaction, the hydrogen gas supplied to the reduction unit 500 can be heated to a temperature of 800 ° C or higher, more preferably 850 ° C or higher. When the reducing gas heated in this way is supplied, the reaction efficiency can be improved.

[0075] In addition, the process (S100) of manufacturing reduced iron may further include a process of supplying a purge gas to the reduction unit 500. Here, the process of supplying the purge gas can be performed by the purge gas supply unit 400 arranged to be able to supply the purge gas to the reduction unit 500 supplying the purge gas into the reduction space via the purge gas supply line PL. At this time, as the purge gas, an inert gas such as nitrogen can be used.

[0076] In the process of reacting the raw material with the reducing gas for reduction, the reduction unit 500 receives the supply of the raw material from the raw material supply unit 100 and the supply of the reducing gas from the reducing gas supply unit 200, and can react the iron ore with the reducing gas for reduction. Such a reduction unit 500 may include a reduction furnace having a reduction space capable of manufacturing reduced iron using the reducing gas. The reduction furnace may be provided as a single unit. However, as described above, in order to effectively reduce low-grade iron ore or powdered iron ore having a low iron content, a plurality of reduction furnaces may be connected to each other to manufacture reduced iron while sequentially moving the raw material.

[0077] On the other hand, in the process of reacting the raw material with the reducing gas for reduction, a large amount of by-products are generated in addition to the reduced iron. The by-products generated and discharged in the reduction unit 500 may include water vapor generated by the reaction of iron ore and hydrogen gas, and may also include hydrogen gas that could not react with the raw material and nitrogen gas supplied to the purge gas. In addition to these, dust generated in the reduction unit 500 can be included in the by-products and discharged. The by-products can move along the flow of the reducing gas in the reduction unit 500 and be discharged from the reduction furnace. Thus, the by-products discharged from the reduction furnace are collected in the process (S200) of collecting the by-products, and the collected by-products are used in the process (S500) of manufacturing the hydrogen-containing gas described later.

[0078] The process (S300) of producing the melt is carried out by the melting section 600 receiving the supply of reduced iron from the reduction section 500 and melting the received reduced iron. That is, the melting section 600 can receive the supply of fine powder or agglomerated reduced iron from the reduction section 500 and heat and melt this. Also, the process (S300) of producing the melt can be carried out by the melting section 600 receiving the supply of reduced iron from the reduction section 500 and melting the received reduced iron using electric heating. At this time, the melting section 600 may be provided with an electric furnace having a melting space capable of melting reduced iron using electric heating. Such an electric furnace may include an electric furnace body having a melting space and electrode rods at least a part of which are arranged in the melting space so as to be capable of generating electric heat. The melting section 600 can apply power to the electrode rods to melt the reduced iron when the melting space is charged with reduced iron.

[0079] Here, the process (S300) of producing the melt may include the process of charging a carbonizing agent into the melting section 600, that is, the melting space of the electric furnace. Pure reduced iron has a high melting point of about 1,500 °C or higher and is difficult to melt. Therefore, in the process (S300) of producing the melt, a carbonizing agent having a carbon component is charged in order to change at least some of the iron particles of the reduced iron into cementite (Fe3C) phase having a melting point of about 1,200 °C or lower. Also, at least a part of the raw material that has not been reduced from the reduction section 500, that is, partially reduced reduced iron or iron ore, can be supplied to the melting section 600. In this way, the raw material that has not been reduced at least in part has an oxygen component, and in the melting space, the oxygen component will react with the carbon component of the carbonizing agent. For this reason, from the reduction section 500, exhaust gas containing carbon monoxide gas, that is, exhaust gas having a high concentration of carbon monoxide (CO-rich) and having a temperature of about 1,200 °C or higher, is discharged during the melting of the reduced iron. In this way, the exhaust gas discharged from the melting section 600 is collected in the process (S400) of collecting the exhaust gas, and the collected exhaust gas is used in the process (S500) of producing the hydrogen-containing gas described later.

[0080] The exhaust gas collected in the process of collecting exhaust gas (S400) can be used not only in the process of producing hydrogen-containing gas (S500), but also in the process of preheating the aforementioned raw materials. That is, in the process of preheating the aforementioned raw materials, a part of the exhaust gas collected in the process of collecting exhaust gas (S400) can be used to preheat the raw materials. Since the exhaust gas has a high temperature of about 1,200 °C or higher, the thermal energy of such exhaust gas can be utilized to preheat the raw materials.

[0081] To describe this in more detail, the process of preheating the raw materials may include a process of directly spraying a part of the exhaust gas discharged from the melting unit 600 onto the raw materials. In the process of supplying the raw materials, the raw materials stored in the storage space of the storage tank 110 are supplied to the reduction unit 500. In such a storage tank 110, a preheating gas supply device 120 may be disposed so as to be able to supply preheating gas to the storage space of the storage tank 110. At this time, in the process of preheating the raw materials, high-temperature exhaust gas having a temperature of about 1,200 °C or higher can be sprayed from the preheating gas supply device 120 onto the raw materials stored in the storage space to preheat the raw materials. Further, the preheating gas supply device 120 can also preheat the raw materials by spraying the heated external air onto the raw materials stored in the storage space. At this time, in the process of preheating the raw materials, the preheating gas supply device 120 can heat the external air with the heat of the exhaust gas having a temperature of 1,200 °C or higher and supply the heated air to the storage space to preheat the raw materials.

[0082] In the process of producing hydrogen-containing gas (S500), hydrogen-containing gas can be produced using the collected by-products and exhaust gas.

[0083] At this time, the process (S500) of manufacturing the hydrogen-containing gas may include a process of directly reacting the collected by-products and the exhaust gas. That is, in the process (S500) of manufacturing the hydrogen-containing gas, without separating a specific substance from the by-products discharged from the reduction unit 500, the by-products can be directly reacted with the exhaust gas to manufacture the hydrogen-containing gas. This can be performed by the molten iron manufacturing facility according to an embodiment of the present invention described above. That is, the process of directly reacting the collected by-products and the exhaust gas is connected to the exhaust gas supply line EL so as to be able to receive the supply of the exhaust gas, and is connected to the by-product supply line BL so as to be able to receive the supply of the by-products, and can be performed by reactors 730 and 740 having a reaction space capable of reacting the exhaust gas and the by-products to generate a hydrogen-containing gas. At this time, the reactors 730 and 740 react the by-products containing water vapor, hydrogen gas, nitrogen gas, etc. with the exhaust gas containing carbon monoxide gas, and the water vapor contained in the by-products and the carbon monoxide gas contained in the exhaust gas are reformed into hydrogen gas and carbon dioxide gas by the water gas shift reaction, and a hydrogen-containing gas containing hydrogen gas, nitrogen gas, and carbon dioxide gas can be manufactured.

[0084] Further, the process (S500) of manufacturing the hydrogen-containing gas may include a process of extracting a reaction object from the collected by-products and a process of reacting the extracted reaction object with the exhaust gas. That is, in the process (S500) of manufacturing the hydrogen-containing gas, a reaction object can be extracted from the by-products discharged from the reduction unit 500 and collected, and this can be reacted with the exhaust gas to manufacture the hydrogen-containing gas. This can be performed by the molten iron manufacturing facility according to another embodiment of the present invention described above. That is, the process of extracting the reaction object is performed by a purifier connected to the by-product supply line BL for collecting the by-products generated from the reduction furnace and capable of extracting the reaction object from the by-products supplied through the by-product supply line BL, and the process of reacting the extracted reaction object with the exhaust gas is connected to the exhaust gas supply line EL and the purifier so as to be able to receive the supply of the exhaust gas and the reaction object respectively, and can be performed by reactors 730 and 740 having a reaction space capable of reacting the exhaust gas and the reaction object to generate a hydrogen-containing gas.

[0085] Here, the process of extracting the reaction target may include a process of spraying a treatment liquid onto the collected by-products to separate the reaction target in a liquid state and a process of heating the reaction target in a liquid state to vaporize it.

[0086] The process of separating the reaction target in a liquid state is connected to the by-product supply line BL, and a separator 710 capable of separating the reaction target in a liquid state from the by-products supplied through the by-product supply line BL sprays a treatment liquid, that is, water, onto the by-products to condense the water vapor in the by-products with water and mix it with water to separate the reaction target in a liquid state, that is, into water. At this time, in the process of separating the reaction target in a liquid state, residual gas containing hydrogen gas and nitrogen gas excluding water vapor and dust can be discharged. Since the residual gas contains hydrogen gas, a second extractor 820 connected to the separator 710 can collect such residual gas and adsorb and desorb the hydrogen component in the collected residual gas to extract hydrogen gas from the residual gas.

[0087] The process of vaporizing can be carried out by a heater 720 receiving the supply of the reaction target in a liquid state, that is, water, from the separator 710 and heating the received water to vaporize it into water vapor. At this time, the process of vaporizing may include a process of heating the reaction target in a liquid state with the heat of the exhaust gas. As described above, this is carried out by a heat exchanger arranged to intersect the exhaust gas supply line EL and transferring the heat of the exhaust gas having a temperature of 1,200 °C or higher to the water supplied from the separator 710 to vaporize the water into water vapor.

[0088] In this way, a part of the reaction target vaporized by the heat exchanger can be used as purge gas. That is, the water vapor produced in the heat exchanger can be partly transmitted to the reactor and the other part can be used as purge gas supplied to the reduction space.

[0089] In the process of reacting the extracted reaction target with the exhaust gas, in the reaction space of the reactor, the exhaust gas supplied through the exhaust gas supply line EL2 via the heat exchanger reacts with the vaporized reaction target supplied through the heat exchanger, that is, water vapor, to generate a hydrogen-containing gas. In this way, when only water vapor, which is the reaction target, is extracted and supplied to the reactor and reacted with the exhaust gas, the reaction efficiency can be further improved.

[0090] In the process (S600) of extracting hydrogen gas, hydrogen gas is extracted from the hydrogen-containing gas. When the collected by-products are directly reacted with the exhaust gas to produce a hydrogen-containing gas, in the process of extracting hydrogen gas, the hydrogen-containing gas can be extracted by a pressure swing adsorption method for extracting hydrogen gas. On the other hand, when the reaction target is extracted from the collected by-products and the extracted reaction target is reacted with the exhaust gas to produce a hydrogen-containing gas, the hydrogen component may be adsorbed and the adsorbed hydrogen component may be desorbed to extract hydrogen gas. Alternatively, the carbon dioxide component may be adsorbed and the hydrogen gas that cannot be adsorbed and is discharged may be collected to extract hydrogen gas.

[0091] The hydrogen gas extracted in the process (S600) of extracting hydrogen gas can be used for a variety of applications. However, the reduction unit 500 uses hydrogen gas to reduce the raw material, that is, iron ore, and the hydrogen gas is used in a large amount more than twice the amount required to reduce all the raw materials supplied to the reduction unit 500. Since it is a very expensive gas, for cost reduction through resource recycling, the hydrogen gas extracted in the extraction unit 800 can be reused as a reducing gas for reducing iron ore. For this reason, the method for producing molten iron according to the embodiment of the present invention can be supplied as a reducing gas during the process (S100) of producing reduced iron and used for reducing iron ore.

[0092] Thus, according to the present invention, by reacting the by-products discharged during the production of reduced iron with the exhaust gas discharged during the melting of reduced iron to produce hydrogen gas, the by-products generated during the process can be effectively recycled.

[0093] Moreover, by reusing the produced hydrogen gas raw material as a reducing gas for reduction, the amount of hydrogen gas used can be reduced, and the resources and costs involved in the process can be minimized as much as possible.

[0094] In addition, by using the sensible heat of the exhaust gas having a high temperature for preheating the raw material and producing hydrogen gas, energy can be efficiently recovered.

[0095] As described above, the preferred embodiments of the present invention have been described and illustrated using specific terms. However, these terms are merely for clearly explaining the present invention, and it is obvious that various changes and modifications can be made to the embodiments of the present invention and the described terms without departing from the technical idea and scope of the claims. These modified embodiments should not be individually understood as departing from the idea and scope of the present invention, but should be said to belong within the scope of the claims of the present invention.

Explanation of Reference Numerals

[0096] 100 Raw material supply section 110 Reservoir 120 Preheating gas supply device 200 Reducing gas supply section 400 Purge gas supply section 500 Reduction section 510, 520, 530, 540 Fluidized reduction furnace 600 Treatment section 700 Melting section 710, 720 Electric furnace 800 Treatment section 810 Main body 812 Reduced iron inlet 816 Exhaust gas inlet 817 Dispersion plate 820 Heater 840 Trap 900 Supplementary gas supply unit

Claims

1. A reduction section capable of producing reduced iron, A melting section capable of melting upon receiving the supply of the reduced iron, Arranged so as to be capable of receiving the supply of the exhaust gas discharged from the melting section and the by-products discharged from the reduction section, and a reforming section capable of producing a hydrogen-containing gas using the exhaust gas and the by-products, Arranged so as to be capable of receiving the supply of the hydrogen-containing gas generated in the reforming section, and an extraction section capable of extracting hydrogen gas from the hydrogen-containing gas, A molten iron production facility characterized by comprising these.

2. A by-product supply line arranged to connect the reduction section and the reforming section, An exhaust gas supply line arranged to connect the melting section and the reforming section, Further comprising, The reduction section is connected to the by-product supply line and includes a reduction furnace having a reduction space capable of producing reduced iron using a reducing gas, The melting section is connected to the exhaust gas supply line and includes an electric furnace having a melting space capable of melting reduced iron using electric heat. The molten iron production facility according to Claim 1, characterized in that.

3. The reforming section, Is connected to the exhaust gas supply line and the by-product supply line so as to be capable of receiving the supply of the exhaust gas and the by-products, and includes a reactor having a reaction space capable of reacting the exhaust gas and the by-products to produce a hydrogen-containing gas. The molten iron production facility according to Claim 2, characterized in that.

4. The reforming section, Is connected to the by-product supply line and includes a purifier capable of extracting a reaction object from the by-products, Is connected to the exhaust gas supply line and the purifier so as to be capable of receiving the supply of the exhaust gas and the reaction object, and includes a reactor having a reaction space capable of reacting the exhaust gas and the reaction object to produce a hydrogen-containing gas. The molten iron production facility according to Claim 2, characterized in that.

5. The purifier, Is connected to the by-product supply line and includes a separator capable of separating a reaction object from the by-products in a liquid state, Is connected to the separator and includes a heater connected to the reactor so as to heat and vaporize the reaction object in a liquid state and supply the vaporized reaction object to the reactor. The molten iron production facility according to Claim 4, characterized in that.

6. The heater, Is arranged to intersect the exhaust gas supply line and includes a heat exchanger capable of transferring the heat of the exhaust gas to the reaction object in a liquid state. The molten iron production facility according to Claim 5, characterized in that.

7. ​ ​ Further provided with a purge gas supply line connected to the reduction furnace and capable of supplying purge gas to the reduction space, The melting iron manufacturing facility according to claim 5, wherein the heater is connected to the purge gas supply line and capable of supplying the vaporized object to be reacted to the purge gas supply line.

8. The extraction unit Is connected to the reactor and includes a first extractor capable of extracting hydrogen gas from the hydrogen-containing gas generated in the reactor, Is connected to the separator and includes a second extractor capable of extracting hydrogen gas from the residual gas discharged from the separator, The melting iron manufacturing facility according to claim 5, characterized by comprising.

9. A raw material supply unit having a storage space capable of storing raw materials and arranged so as to be able to supply the raw materials stored in the storage space to the reduction space, A branch line branched from the exhaust gas supply line and capable of supplying a part of the exhaust gas discharged from the electric furnace to the raw material supply unit, The melting iron manufacturing facility according to claim 2, further comprising.

10. The melting iron manufacturing facility according to claim 9, characterized in that the branch line is connected to the raw material supply unit so as to be able to directly supply exhaust gas to the storage space or to transfer the heat of the exhaust gas to the air supplied to the storage space.

11. Further provided with a reduction gas supply line connected to the reduction furnace and capable of supplying reduction gas to the reduction space, The melting iron manufacturing facility according to claim 2, wherein the extraction unit is connected to the reduction gas supply line and capable of supplying hydrogen gas to the reduction gas supply line.

12. A process of manufacturing reduced iron, A process of collecting by-products generated in the process of manufacturing the reduced iron, A process of melting the reduced iron to produce a melt, A process of collecting exhaust gas discharged in the process of producing the melt, A process of producing a hydrogen-containing gas using the collected by-products and exhaust gas, A process of extracting hydrogen gas from the hydrogen-containing gas, A method for manufacturing molten iron, characterized by including.

13. The process of manufacturing the reduced iron A process of preheating raw materials using the exhaust gas, A process of reducing the preheated raw materials by reacting them with a reduction gas, The method for manufacturing molten iron according to claim 12, characterized by including.

14. The process of preheating the raw materials The method for producing molten iron according to claim 13, comprising a process of spraying the exhaust gas onto the raw material or spraying air heated by receiving heat transfer of the exhaust gas onto the raw material.

15. The method for producing molten iron according to claim 13, wherein the raw material includes powdered iron ore having a particle size exceeding 0 mm and not exceeding 8 mm.

16. The process of producing the hydrogen-containing gas The method for producing molten iron according to claim 12, comprising a process of directly reacting the collected by-products with the exhaust gas.

17. The process of producing the hydrogen-containing gas includes a process of extracting a reaction object from the collected by-products, and a process of reacting the extracted reaction object with the exhaust gas. The method for producing molten iron according to claim 12, characterized by including the above.

18. The process of extracting the reaction object includes a process of spraying a treatment liquid onto the collected by-products to separate the reaction object in a liquid state, and a process of heating and vaporizing the reaction object in a liquid state. The method for producing molten iron according to claim 17, characterized by including the above.

19. The process of vaporizing The method for producing molten iron according to claim 18, characterized by including a process of heating the reaction object in a liquid state by the heat of the exhaust gas.

20. The process of producing the reduced iron includes a process of supplying a purge gas to a reduction space for producing the reduced iron, The process of supplying the purge gas The method for producing molten iron according to claim 18, characterized by including a process of using a part of the vaporized reaction object as the purge gas supplied to the reduction space.

21. a process of collecting residual gas discharged in the process of separating the reaction object in a liquid state, and a process of extracting hydrogen gas from the residual gas. The method for producing molten iron according to claim 18, further characterized by including the above.

22. The method for producing molten iron according to claim 12, further characterized by including a process of supplying the extracted hydrogen gas during the process of producing the reduced iron.

23. The reaction object contains water vapor, The method for producing molten iron according to any one of claims 17 to 21, wherein the exhaust gas contains carbon monoxide gas.

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