Molten iron production facility and molten iron production method

Abstract

The present disclosure relates to a facility and a method for manufacturing molten iron, and more particularly, to a facility and a method for manufacturing reduced iron and smelting the manufactured reduced iron to manufacture molten iron. A facility for manufacturing molten iron according to one exemplary embodiment includes: a reduction unit configured to manufacture reduced iron; a smelting part configured to smelt reduced iron; and a treatment part provided to receive the reduced iron from the reduction part and the exhaust gas discharged from the smelting part such that the supplied reduced iron and the exhaust gas react with each other to supply the reacted reduced iron to the smelting part.

Description

Technical Field

[0001] The present disclosure relates to a facility and a method for manufacturing molten iron, and more particularly, to a facility and a method for manufacturing reduced iron and smelting the manufactured reduced iron to manufacture molten iron. Background Art

[0002] Generally, molten iron (i.e., molten iron) is manufactured by a furnace process. The furnace process is performed by processing iron ore and coal into a form suitable for use, placing the processed iron ore and coal into a furnace, and blowing hot air into the furnace. Here, the hot air burns the coal, and the carbon monoxide gas generated at this time causes a reduction reaction that removes oxygen from the iron ore. In addition, the heat generated inside the furnace at a temperature higher than about 1,500°C causes a smelting reaction that smelts the iron ore or the iron reduced by the carbon monoxide gas to make molten iron. In such a furnace process, the reduction reaction and the smelting reaction are carried out simultaneously in the furnace by the coal and the carbon monoxide gas generated by the coal. However, the furnace process has such a limitation that a large amount of carbon dioxide is produced due to the reduction reaction between the carbon monoxide gas and the iron ore, which leads to environmental problems such as global warming.

[0003] To address this limitation, hydrogen reduction ironmaking process technology is being researched and developed, which uses hydrogen instead of fossil fuels such as coal to make molten iron. Fossil fuels such as coal produce carbon dioxide when reacting with iron ore, but since hydrogen reacts with iron ore to produce water or water vapor, the hydrogen reduction ironmaking process can innovatively reduce carbon emissions in molten iron manufacturing.

[0004] In the hydrogen reduction ironmaking process, reduced iron can be manufactured by reducing iron ore, and molten iron can be manufactured by smelting the manufactured reduced iron. However, the reduced iron manufactured by the reaction between hydrogen and iron ore has a very high melting point, and therefore, there is a limitation that a large amount of energy is required to smelt the reduced iron. In addition, in the process of smelting the reduced iron, a large amount of waste gas is generated, and a method for recovering the large amount of waste gas generated in this way needs to be prepared.

[0005] (Prior art literature)

[0006] Korean Patent Registration No. 10-1699236 Summary of the invention

[0007] Technical issues

[0008] The present disclosure provides facilities and methods for producing molten iron that can minimize the amount of energy required for smelting.

[0009] Technical Solution

[0010] According to an exemplary embodiment, a facility for manufacturing molten iron includes: a reduction section configured to manufacture reduced iron; a smelting section configured to smelt the reduced iron; and a processing section configured to receive the reduced iron from the reduction section and the exhaust gas discharged from the smelting section so that the supplied reduced iron and the exhaust gas react with each other to supply the reacted reduced iron to the smelting section.

[0011] The facility may further include an exhaust gas supply line arranged to be connected to the smelting section and the processing section, wherein the reduction section may include a reduction furnace having a reduction space in which reducing gas is supplied to produce reduced iron, and the smelting section may include an electric furnace having a smelting space in which electric heating is used to smelt the reduced iron supplied from the processing section.

[0012] The processing section may include: a main body having a processing space; a reduced iron inlet, which is arranged in the main body to allow reduced iron to flow into the processing space; and an exhaust gas inlet, which is arranged in the main body and connected to the exhaust gas supply pipeline so that the exhaust gas is introduced into the processing space, wherein the exhaust gas inlet may be arranged at a position lower than the reduced iron inlet.

[0013] The processing part may further include a heater installed in the body to heat the processing space.

[0014] The processing part may include: a collector connected to the main body to collect reduced iron discharged from the main body; and a circulation line configured to connect the collector with the main body so that the reduced iron collected by the collector is supplied to the main body.

[0015] The processing part may further include a supplementary gas supply part connected to the main body so as to supply a supplementary gas having at least a portion of the same component as the exhaust gas to the processing space.

[0016] The facility may also include: a raw material supply section having a storage space in which the raw material is stored and configured to supply the raw material stored in the storage space to the reduction space; and an exhaust gas branch line branched from the exhaust gas supply line and configured to supply a portion of the exhaust gas discharged from the electric furnace to the raw material supply section.

[0017] The exhaust gas branch line may be connected to the raw material supply part to directly supply the exhaust gas to the storage space or transfer heat of the exhaust gas to air supplied to the storage space.

[0018] The facility may also include: a purge gas supply line connected to the reduction furnace to supply the purge gas to the reduction space; and a purge gas branch line branched from the purge gas supply line and configured to supply a portion of the purge gas supplied to the reduction space to the processing space.

[0019] According to another exemplary embodiment, a method for manufacturing molten iron includes: manufacturing reduced iron; allowing the manufactured reduced iron to react with a process gas; smelting the reacted reduced iron to manufacture a molten product; and utilizing at least a portion of exhaust gas generated when manufacturing the molten iron as a process gas that reacts with the reduced iron.

[0020] Manufacturing the reduced iron may include: preheating a raw material using exhaust gas; and allowing the preheated raw material to react with a reducing gas to reduce the raw material.

[0021] Preheating the feedstock may include injecting exhaust gas into the feedstock or receiving heat from the exhaust gas to inject heated air into the feedstock.

[0022] The raw material may include powdered iron ore having a particle size greater than about 0 mm and less than or equal to about 8 mm.

[0023] The process gas may include a gas including a carbon component, and the reaction with the process gas may include carbonizing at least a portion of the reduced iron.

[0024] Allowing the reduced iron to react with the process gas may include reacting with the process gas without separately heat-treating the produced reduced iron.

[0025] Allowing the reduced iron to react with the process gas may include allowing the produced reduced iron to react with the process gas at a temperature of about 600°C to about 800°C.

[0026] The method may further include: collecting reduced iron discharged from the process space in which the reduced iron reacts with the process gas; and supplying the collected reduced iron to the process space.

[0027] The producing of molten iron may include supplying a purge gas to a reduction space in which reduced iron is produced, and allowing the reduced iron to react with the process gas may include supplying a portion of the purge gas supplied to the reduction space to the process space.

[0028] Utilizing at least a portion of the exhaust gas as the process gas may include utilizing the exhaust gas and a make-up gas having at least a portion of the same composition as the exhaust gas as the process gas.

[0029] The exhaust gas may include carbon monoxide gas, and the supplemental gas may include at least one of natural gas or biomass gas.

[0030] Beneficial Effects

[0031] According to an exemplary embodiment, the amount of energy used to smelt the reduced iron may be minimized by allowing exhaust gas generated in the process to react with the reduced iron to lower the melting point of the reduced iron.

[0032] Furthermore, reduced iron manufactured at high temperature can directly react with high-temperature exhaust gas to minimize facilities and resources required for the reaction.

[0033] In addition, energy can be efficiently collected by utilizing the sensible heat of high-temperature exhaust gas to preheat the raw materials and generate hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic diagram of a facility for producing molten iron according to an exemplary embodiment.

[0035] Figure 2 is a diagram showing an example of a reducing furnace for producing reduced iron and an electric furnace for smelting reduced iron;

[0036] Figure 3 is a diagram showing an example of a processing section according to an exemplary embodiment;

[0037] Figure 4 is a diagram showing the conditions for the reaction of reduced iron with exhaust gas;

[0038] Figure 5 is a diagram showing a state in which the raw material is preheated by exhaust gas in the raw material supply unit; and

[0039] Figure 6 is a schematic diagram of a method for manufacturing molten iron according to an exemplary embodiment. DETAILED DESCRIPTION

[0040] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can be embodied in different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present invention will be detailed and complete, and will fully convey the scope of the present invention to those skilled in the art. In order to explain the present disclosure in detail, the accompanying drawings may be enlarged, and the same reference numerals in the accompanying drawings refer to the same elements.

[0041] Figure 1 is a schematic diagram of a facility for producing molten iron according to an exemplary embodiment. Figure 2 is a diagram showing an example of a reducing furnace for producing reduced iron and an electric furnace for smelting reduced iron, and Figure 3 is a diagram showing an example of a processing section according to an exemplary embodiment, Figure 4 is a diagram showing the conditions for the reaction of reduced iron with exhaust gas, and Figure 5 2 is a diagram showing a state in which the raw material is preheated by exhaust gas in the raw material supply unit. In the figure, arrows indicated by dotted lines indicate flows of the raw material and reduced iron, and arrows indicated by solid lines indicate flows of by-products and gas.

[0042] Reference Figures 1 to 5 , a facility for manufacturing molten iron according to an exemplary embodiment may include a reduction part 500 capable of manufacturing reduced iron; a smelting part 700 capable of smelting reduced iron; and a treatment part 600, the treatment part 600 receiving the molten iron from the reduction part 500, being configured to receive the exhaust gas discharged from the smelting part 700, and allowing the supplied reduced iron and the exhaust gas to react with each other, so that the reacted reduced iron is supplied to the smelting part 700. In addition, the facility for manufacturing molten iron according to an exemplary embodiment may further include a raw material supply part 100 configured to supply a raw material to the reduction part 500 and a reducing gas supply part 200 configured to supply a reducing gas to the reduction part 500.

[0043] The raw material supply part 100 may be configured to supply the raw material to the reduction part 500. Here, the raw material may include iron ore, and the iron ore may include reduced fine iron ore, i.e., powdered iron ore having a particle size greater than about 0 mm and less than or equal to about 8 mm. The raw material supply part 100 may include a storage tank 110 having a storage space in which the raw material is stored. The raw material may be stored in the storage space of the storage tank 110 for a long time, or may be temporarily stored before the raw material is supplied to the reduction part 500. The storage tank 110 may include, for example, a hopper.

[0044] The raw material may be preheated in the storage space of the storage tank 110, and the raw material preheated in the storage space may be supplied to the reduction part 500. Here, the storage tank 110 may receive a portion of the exhaust gas discharged from the smelting part 700 to preheat the raw material. To this end, the facility for manufacturing molten iron according to an exemplary embodiment may further include an exhaust gas branch line EDL branched from the exhaust gas supply line EL to supply a portion of the exhaust gas discharged from the smelting part 700 to the storage tank 110. This will be referred to later. Figure 5 Description Preheating of the raw material using the exhaust gas supplied through the exhaust gas branch line EDL.

[0045] The reducing gas supply unit 200 may be configured to store the reducing gas and supply the reducing gas to the reducing unit 500. Here, the reducing gas may contain hydrogen, and the hydrogen may be contained at a ratio of about 80% to about 100% of the total reducing gas. The hydrogen stored in the reducing gas supply unit 200 may be generated by electrolysis of water, but is not limited thereto, and may be generated by various methods such as decomposing ammonia or by chemically reacting natural gas to generate hydrogen. For example, ammonia may be decomposed into hydrogen and nitrogen at high temperature, the decomposed hydrogen may be used as a reducing gas, and the nitrogen may be used as a purge gas, which will be described later.

[0046] The reducing gas supply part 200 may supply the reducing gas to the reducing part 500 through the reducing gas supply lines RL1 and RL2 connecting the reducing gas supply part 200 with the reducing part 500. Here, the amount of the reducing gas supplied to the reducing part 500 by the reducing gas supply part 200 may be more than twice the amount required to completely reduce the raw material supplied to the reducing part 500. In order to improve the reaction efficiency between the raw material and the reducing gas, the amount of the reducing gas may be controlled within a range of, for example, two to three times the amount required to completely reduce the raw material supplied to the reducing part 500.

[0047] A heating part 300 may be installed in each of the reducing gas supply lines RL1 and RL2 to heat the reducing gas supplied from the reducing gas supply part 200 to the reducing part 500. In the reducing part 500, the raw material containing iron ore and the reducing gas containing hydrogen may react to reduce the iron ore. Since the reaction between the iron ore and the hydrogen is a strong endothermic reaction, when the hydrogen supplied to the reducing part 500 is heated and supplied to a temperature of about 800°C or higher, more preferably about 850°C or higher, the reaction efficiency may be improved. Therefore, the heating part 300 may be connected to the reducing gas supply part 200 through the first reducing gas supply line RL1, and may also be connected to the reducing part 500 through the second reducing gas supply line RL2 to heat the low-temperature hydrogen supplied through the first reducing gas supply line RL1 to a temperature of about 800°C to about 1,200°C, thereby supplying hydrogen to the reducing part 500 through the second reducing gas supply line RL2. Since the heating part 300 may have various structures for heating the reducing gas in a direct or indirect heating manner, a detailed description thereof will be omitted.

[0048] The facility for manufacturing molten iron according to an exemplary embodiment may also include a purge gas supply unit 400, which is configured to store purge gas and supply purge gas to the reduction unit 500. The reduction unit 500 may have a reduction space capable of producing reduced iron, and the reduction space may need to be purged for maintenance between processes. In addition, there is a situation where purge gas needs to be supplied during the process. For example, when powdered iron ore is used as a raw material, purge gas can be supplied to increase the fluidity of the powdered iron ore, thereby preventing the iron ore from adhering to the reduction space. Therefore, the purge gas supply unit 400 can supply purge gas to the reduction space through a purge gas supply line PL connecting the purge gas supply unit 400 to the reduction unit 500, and an inert gas such as nitrogen can be used as the purge gas.

[0049] The reduction section 500 may produce reduced iron by reducing the raw material. That is, the reduction section 500 may receive iron ore from the raw material supply section 100 as the raw material, receive the reducing gas from the reducing gas supply section 200, and react the iron ore with the reducing gas to produce reduced iron. The reduction section 500 may include a reduction furnace having a reduction space capable of producing reduced iron using the reducing gas. The reduction furnace may include flowing reduction furnaces 510, 520, 530, and 540 that produce reduced iron while allowing the raw material to flow, and the flowing reduction furnaces 510, 520, 530, and 540 may be provided as a single unit. However, in order to effectively reduce low-grade iron ore or powdered iron ore having a low iron content, such as Figure 2 As shown, a plurality of flow reduction furnaces 510, 520, 530 and 540 may be connected to sequentially move raw materials to produce reduced iron. Here, there is no limitation on the number of flow reduction furnaces 510, 520, 530 and 540, but in order to sufficiently reduce the raw materials, and as shown in FIG. Figure 2 As shown, the reduction part 500 may include four reduction furnaces including a first flow reduction furnace 510, a second flow reduction furnace 520, a third flow reduction furnace 530, and a fourth flow reduction furnace 540. Here, the raw material supply part 100 may supply the raw material to the first flow reduction furnace 510, and the reducing gas supply part 200 may supply the reducing gas to the fourth flow reduction furnace 540. The raw material supplied to the first flow reduction furnace 510 may be reduced by sequentially moving through the second flow reduction furnace 520, the third flow reduction furnace 530, and the fourth flow reduction furnace 540, and thus manufactured into reduced iron.

[0050] The reduced iron produced in the reducing part 500 may be supplied to the processing part 800 which will be described later. Figure 2 As shown in , the reduced iron manufactured by the first flow reduction furnace 510, the second flow reduction furnace 520, the third flow reduction furnace 530 and the fourth flow reduction furnace 540 can be discharged from the fourth flow reduction furnace 540 and supplied to the processing section 800. Here, as described above, the preheated raw material and the reducing gas with a temperature of about 800°C or higher can be supplied to the reduction space to manufacture the reduced iron. Therefore, even considering the heat loss, the reduced iron manufactured in the reduction section 500 can be discharged at a high temperature of, for example, about 600°C to about 800°C. As described above, the reduced iron discharged at high temperature can be directly supplied to the processing section 800 without passing through a separate heat treatment device. In the processing section 800, the reduced iron manufactured at high temperature can be directly reacted with the high-temperature exhaust gas to minimize the facilities and resources required for the reaction, which will be described later with respect to the processing section 800.

[0051] In the reduction section 500, in addition to the reduced iron, a large amount of by-products may be discharged. The by-products discharged from the reduction section 500 may include water vapor. As described above, in the reduction section 500, iron ore and hydrogen may react to produce reduced iron. Here, the oxygen component of the iron ore and the hydrogen component of the hydrogen may react to produce a large amount of water vapor in the reduction space, and the produced water vapor may be discharged from the reduction section 500 as a by-product. In addition, the by-products discharged from the reduction section 500 may include hydrogen and nitrogen. As described above, the reducing gas may be supplied in a range of two to three times the amount required to completely reduce the raw material supplied to the reduction section 500, and therefore, the remaining hydrogen that has not reacted with the raw material may be discharged from the reduction section 500 as a by-product. In addition, as described above, a purge gas (e.g., nitrogen) may be supplied to the reduction section 500 for various reasons. As described above, the nitrogen supplied for purging may be discharged from the reduction section 500 as a by-product. The by-products may move along the reducing gas flow in the reduction section 500 and then be discharged from the first flow reduction furnace 510. Then, the discharged by-product may be supplied to the extraction part 600 through the by-product supply line BL connected to the reduction part 500 .

[0052] That is, the facility for manufacturing molten iron according to an exemplary embodiment may further include an extraction part 600 configured to receive the by-products discharged from the reduction part 500 and extract hydrogen from the by-products.

[0053] The extraction section 600 can extract hydrogen from the byproducts discharged from the reduction section 500. As described above, the byproducts discharged from the reduction section 500 may include water vapor, hydrogen and nitrogen. The extraction section 600 can be connected to the reduction section 500 through the byproduct supply line BL to extract hydrogen from the byproducts supplied through the byproduct supply line BL. The extraction section 600 can extract hydrogen from the byproducts using a pressure swing adsorption (PSA) method. That is, in the pressure swing adsorption method, the gas can be extracted using the adsorption selectivity of each component relative to the adsorbent, and the extraction section 600 can use a carbon molecular sieve as an adsorbent capable of adsorbing hydrogen components to extract hydrogen from byproducts including various gases other than hydrogen. Here, the hydrogen component adsorbed on the adsorbent can be desorbed and extracted as hydrogen, and the extraction section 600 can extract hydrogen from the byproducts by repeatedly adsorbing and desorbing the hydrogen component.

[0054] The unadsorbed residue discharged from the extraction section 600 may contain water vapor and nitrogen. Here, the residue containing water vapor and nitrogen may be supplied to the reduction section 500 as a purge gas. As a reaction product produced by the reaction of the iron ore as a raw material with the hydrogen in the reducing gas, the water vapor may have a low reactivity with the iron ore and the reducing gas, and thus may be supplied to the reduction section 500 as a purge gas. In addition, when the water vapor is supplied to the reduction section 500 as a purge gas, the heat of the water vapor may be used for the reduction reaction to save the energy required for the reduction reaction. In order to supply the residue as a purge gas to the reduction section 500, a residue discharge line (not shown) may be connected to the extraction section 600, and the residue discharge line may be connected to the purge gas supply line PL or directly connected to the reduction section 500 to supply the residue to the reduction section 500 through a path different from the path of the purge gas.

[0055] The hydrogen extracted from the extraction section 600 can be used for various purposes. For example, the reduction section 500 can utilize the extracted hydrogen to reduce the raw material, i.e., iron ore. Hydrogen can be used in large quantities (more than twice the amount required to completely reduce the raw material supplied to the reduction section 500), but hydrogen is a very expensive gas, and therefore, in order to reduce costs through resource recovery, the hydrogen extracted from the extraction section 600 can be reused as a reducing gas for reducing the iron ore. To this end, the hydrogen supply line HL can be connected to the extraction section 600, and the hydrogen supply line HL can be connected to the first reducing gas supply line RL1, and therefore, the extraction section 600 can supply hydrogen to the first reducing gas supply line RL1, and the extracted hydrogen can be supplied to the reduction section 500 along the hydrogen supply line HL, the first reducing gas supply line RL1, and the second reducing gas supply line RL2, and then used when reducing the iron ore.

[0056] The smelting section 700 may receive the reduced iron reacted in the processing section 800 to be described later, thereby smelting the reduced iron in various ways. For example, the smelting section 700 may receive the fine or compacted reacted reduced iron from the processing section 800 to heat and smelt the reduced iron. In addition, the smelting section 700 may receive additional iron scraps in addition to the reacted reduced iron, and smelt the reacted reduced iron and the iron scraps together. The smelting section 700 may include electric furnaces 710 and 720 having a smelting space capable of smelting the reacted reduced iron using electrical heating. The above-mentioned electric furnaces 710 and 720 may include an electric furnace body 710 having a smelting space and an electrode rod 720, at least a portion of which is partially arranged in the smelting space to generate electrical heat. When the reacted reduced iron is charged into the smelting space, the electric furnaces 710 and 720 may supply power to the electrode rod 720 to smelt the reacted reduced iron.

[0057] In the smelting section 700, a recarburizer containing a carbon component may be introduced to adjust the carbon content of the molten product manufactured by smelting the reduced iron of the reaction. In addition, the recarburizer may be added to generate a large amount of slag when the molten product is smelted. In this case, the electrode rod 720 may generate resistance heat by receiving electricity when immersed in the slag, and the reduced iron may be more easily smelted by the generated resistance heat. At least part of the unreduced raw material (i.e., partially reduced iron or iron ore) may be supplied to the smelting section 700. As described above, at least a portion of the unreduced raw material may have an oxygen component, and the oxygen component may react with the carbon component of the recarburizer or the carbon component of the reacted reduced iron (which will be described later) in the smelting space. Therefore, in the smelting section 700, the exhaust gas containing carbon monoxide gas, i.e., the exhaust gas having a high carbon monoxide concentration (rich in CO), may be discharged while the reduced iron is smelted by receiving the reacted reduced iron from the processing section 800. As described above, the exhaust gas discharged from the smelting part 700 may be discharged at a high temperature of about 1,200° C. or more.

[0058] When the reduced iron produced in the reduction part 500 is charged into the smelting part 700 without being separately treated, a large amount of energy may be required to smelt the reduced iron in the smelting part 700. That is, the reduced iron produced in the reduction part 500 (without any additional treatment) may have a component of metallic iron (Fe) (i.e., pure iron), and the melting point of the pure iron may be about 1,538° C. In addition, the reduced iron may contain a large amount of gangue in addition to the pure iron component, and the reduced iron may be smelted only when heated to a temperature higher than the melting point of the pure iron. In addition, when the reduced iron produced in the reduction part 500 is charged into the smelting part 700 without being separately treated, a large amount of recarburizer may be required to control the carbon content of the molten product.

[0059] On the other hand, when the reduced iron is carburized, the pure iron component may become a cementite (Fe3C) phase, the melting point of which is about 1,200°C or less. As described above, when the reduced iron in which at least a portion of the component becomes a cementite (Fe3C) phase is smelted, the amount of energy used to smelt the reduced iron may be minimized. In addition, when the carburized reduced iron (i.e., iron carbide) is smelted, the molten product may contain some carbon components. Therefore, when the iron carbide is smelted, the amount of the carburizer used to control the carbon content of the melt may be minimized.

[0060] Therefore, in an exemplary embodiment, it may be installed that the reduced iron supplied from the reduction part 500 reacts with the exhaust gas having a high carbon monoxide concentration (rich in CO) discharged from the smelting part 700, and the reacted iron carbide is supplied to the processing part 800 of the smelting part 700. To this end, the facility for manufacturing molten iron according to an exemplary embodiment may further include an exhaust gas supply line EL provided to be connected to the smelting part 700 and the processing part 800.

[0061] Here, if Figure 3 As shown, the processing portion 800 may include a body 810 having a processing space, a reduced iron inlet 812 disposed in the body 810 to allow reduced iron to flow into the processing space, and an exhaust gas inlet 816 disposed in the body 810 and connected to the exhaust gas supply line EL so as to introduce exhaust gas into the processing space.

[0062] The main body 810 may have a processing space for accommodating reduced iron supplied by the reduction part 500. In order to introduce the reduced iron into the processing space, a reduced iron inlet 812 may be provided in the main body 810, and a reduced iron supply pipe FL may be connected to the reduced iron inlet 812 so that the reduced iron manufactured and transmitted by the reduction part 500 is introduced into the processing space through the reduced iron supply pipe FL. In addition, exhaust gas discharged from the smelting part 700 may be introduced into the processing space of the main body 810. To this end, an exhaust gas inlet 816 may be provided in the main body 810, and the exhaust gas inlet 816 may be connected to the exhaust gas supply line EL. Figure 3 , the processing part 800 may be represented as being provided as a single body 810, but the processing part 800 may carbonize the reduced iron while sequentially moving the reduced iron by connecting a plurality of bodies 810 to each other.

[0063] Here, the exhaust gas inlet 816 may be disposed at a position lower than the reduced iron inlet 812. Figure 3 As shown, the exhaust gas inlet 816 may be provided on the bottom surface of the main body 810, and the reduced iron inlet 812 may be provided on the side surface of the main body 810. As described above, the exhaust gas inlet 816 may be provided at a position lower than the reduced iron inlet 812, and thus, the reduced iron supplied by the reduced iron inlet 812 may flow within the main body 810 to react with the exhaust gas. The treatment part 800 may further include a dispersion plate 817 installed in the main body 810 and provided with a plurality of nozzles (not shown) to uniformly disperse the exhaust gas supplied from the exhaust gas inlet 816 into the treatment space.

[0064] Here, the reduced iron produced in the reduction section 500 may be discharged at a high temperature of, for example, about 600°C to about 800°C, and the discharged reduced iron may be directly supplied to the processing section 800 without passing through a separate heat treatment device. In addition, since high-temperature exhaust gas having a temperature of about 1,200°C or higher is supplied to the processing space, the processing space may maintain a temperature of about 600°C to about 800°C even if the heat loss of the reduced iron during the transfer is considered. Therefore, the processing section 800 may not be installed with a separate heating tool for heating the processing space. However, since the temperature of the processing space needs to be additionally increased during the initial operation of the facility, the processing section 800 may also include a heater 820 installed in the main body 810 to heat the processing space. Here, the heater 820 may be selectively operated to heat the processing space when the processing space needs to be heated. For example, the heater 820 may be installed on the side surface of the main body 810 to supply oxygen, and the supplied oxygen may react with the exhaust gas in the processing space to increase the temperature of the processing space. Here, the amount of oxygen supplied by the heater 820 may be controlled to maintain the processing space at a temperature within a range of about 600° C. to about 800° C.

[0065] The processing unit 800 may carbonize the reduced iron supplied from the reduction unit 500 by reacting the reduced iron with the exhaust gas. Figure 4 As shown in the Bauer-Glaessner diagram showing the conditions for the reaction of reduced iron with exhaust gas, when the processing space is maintained at a temperature of about 600°C to about 800°C, when the partial pressure of carbon monoxide and the partial pressure of carbon dioxide in the processing space specify specific conditions, the reduced iron can be carbonized by a reaction according to the following reaction formula.

[0066] [Reaction formula]

[0067] 3Fe+CO→Fe3C+CO2

[0068] That is, when the reduced iron and the exhaust gas are supplied to the processing space at a high temperature, and the processing space is maintained at a temperature of about 600°C to about 800°C, when the partial pressure Pco of carbon monoxide is greater than about 90% of the sum of the partial pressure Pco of carbon monoxide and the partial pressure Pco2 of carbon dioxide (Pco+Pco2), the reduced iron may react according to the above reaction formula and be carbonized. Here, as described above, the smelting part 700 may include electric furnaces 710 and 720 capable of smelting reduced iron, i.e., an electric smelting furnace (ESF) or a submerged arc furnace (SAF), which is immersed in the slag provided in the electric furnace body 710 to smelt the reduced iron with the slag resistance heat. As described above, the electric furnaces 710 and 720 may have a closed structure, and there may be almost no inflow of oxygen or atmosphere, and therefore, the carbon dioxide content in the exhaust gas may be very low, and the oxygen component of the unreduced raw material may react with the carbon component of the carburizer, resulting in a high carbon monoxide concentration. That is, the partial pressure Pco of carbon monoxide discharged from the electric furnaces 710 and 720 can be about 90% or more of the sum of the partial pressures of carbon monoxide Pco and carbon dioxide Pco2 (Pco+Pco2), and therefore, the reduced iron can be effectively carbonized under a temperature condition of about 600°C to about 800°C.

[0069] The facility for manufacturing molten iron according to an exemplary embodiment may further include a supplementary gas supply part 900 configured to supply a supplementary gas having at least a portion of the same component as the exhaust gas to the processing space of the processing part 800. The supplementary gas supply part 900 may supply the supplementary gas, i.e., a carbon-containing gas having at least some of the same component as the exhaust gas, to the processing part 800, and the supplementary gas supply part 900 may supply the carbon-containing gas to the processing part 800 through a supplementary gas supply line SL. Here, the supplementary gas supply line SL may be connected to the exhaust gas supply line EL to supply the supplementary gas together with the exhaust gas, or the supplementary gas may be supplied to the processing part 800 through a path different from the exhaust gas supply line EL, and the supplementary gas may contain at least one of a natural gas containing carbon or a biomass gas obtained by gasifying biomass.

[0070] In addition, the facility for manufacturing molten iron according to an exemplary embodiment may further include a purge gas branch line PDL branched from the purge gas supply line PL to supply a portion of the purge gas supplied to the reduction space to the processing space. The processing space needs to be purged for maintenance, and the purge gas may be supplied to prevent the reduced fine iron from adhering to the processing space during processing. Therefore, the purge gas branch line PDL may be branched from the purge gas supply line PL to supply the purge gas to the processing space.

[0071] As described above, the reduced iron (i.e., iron carbide) reacted in the processing section 800 may be supplied to the smelting section 700. Here, the reaction between the reduced iron and the exhaust gas according to the above reaction formula may correspond to an exothermic reaction. Therefore, even in consideration of heat loss, the iron carbide supplied from the processing section 800 to the smelting section 700 may be discharged at a high temperature within a range similar to the temperature of the processing space (e.g., about 600° C. to about 800° C.). As described above, the iron carbide discharged in a high temperature state may be directly supplied to the smelting section 700 in a high temperature state without passing through a separate cooling device, so as to minimize the amount of energy used to smelt the reduced iron.

[0072] On the other hand, most of the reduced iron supplied to the processing space may react in the processing space and then be supplied to the smelting part 700, but the reduced iron in the molten fine iron may not react sufficiently with the exhaust gas, but flow through the exhaust gas and then be discharged to the outside of the processing space together with the exhaust gas. Therefore, the processing part 800 may also include a collector 840 connected to the main body 810 to collect the reduced iron discharged from the main body 810 and a circulation line CL through which the reduced iron collected by the collector 840 is supplied to the main body 810. Here, the collector 840 may be installed to the upper part of the main body 810 and connected to the exhaust pipe XL through which the exhaust gas is discharged, and the reduced fine iron collected by the collector 840 may be resupplied to the processing space of the main body 810 through the circulation line CL. Here, the circulation line CL may be directly connected to the processing space, but may also be connected to the above-mentioned reduced iron supply pipe FL to resupplied the reduced fine iron collected by the collector 840 to the processing space of the main body 810.

[0073] As described above, the exhaust gas discharged from the smelting part 700 may be supplied to the processing part 800 and used to carbonize the reduced iron. However, as described above, the exhaust gas discharged from the smelting part 700 may be discharged at a high temperature of about 1,200° C. or higher. Therefore, in an exemplary embodiment, the raw material may be preheated by using the heat energy of the exhaust gas.

[0074] like Figure 5 As shown, the raw material supply unit 100 may include a storage tank 110, and the storage tank 110 may have a storage space for storing the raw material. The raw material may be preheated in the storage space of the storage tank 110, and the raw material preheated in the storage space may be supplied to the reduction unit 500. To this end, the raw material supply unit 100 may further include a preheating gas supply unit 120 configured to supply preheating gas to the storage space of the storage tank 110. Here, as shown in FIG. Figure 5 As shown in (a), the preheating gas supply part 120 may be connected to the exhaust gas branch line EDL to directly supply the high-temperature exhaust gas E having a temperature of about 1,200° C. or higher to the storage space for preheating. Figure 5As shown in (b), the preheating gas supply part 120 can heat the external air A supplied to the storage space with the heat of the exhaust gas having a temperature of about 1,200°C or higher to supply the heated air to the storage space, thereby preheating the raw material. To this end, the preheating gas supply part 120 can be provided on the exhaust gas branch line EDL to intersect with the exhaust gas branch line EDL, and thus, the sensible heat of the exhaust gas passing through the exhaust gas branch line EDL can be transferred to the external air A.

[0075] The facility for manufacturing molten iron according to an exemplary embodiment can manufacture reactive molten iron by moving reduced iron and exhaust gas along each of the above-mentioned pipes. The movement of reduced iron and exhaust gas can be controlled by valves (not shown) installed in the pipes, and the valves can be installed at various positions to control the flow rate and flow rate of reduced iron and exhaust gas moving along the corresponding pipes.

[0076] Hereinafter, a method for manufacturing molten iron according to an exemplary embodiment will be described. The method for manufacturing molten iron according to an exemplary embodiment may be a method for manufacturing molten iron using the above-mentioned facility for manufacturing molten iron, and therefore, since the above-mentioned content related to the facility for manufacturing molten iron is applied as it is, the description of the repeated content will be omitted.

[0077] Figure 6 is a schematic diagram of a method for manufacturing molten iron according to an exemplary embodiment.

[0078] Reference Figure 6 , a method for manufacturing molten iron according to an exemplary embodiment may include a process S100 of manufacturing reduced iron, a process S200 of allowing the manufactured reduced iron to react with a process gas, a process S300 of smelting the reacted reduced iron to manufacture a molten product, and a process S400 of using exhaust gas generated in the process of manufacturing the molten product as a process gas for reacting with the reduced iron. Here, since the respective processes are continuously performed to manufacture molten iron, they may not correspond to a time-series relationship in which another process is performed after completing one process.

[0079] The process S100 of manufacturing reduced iron may be performed by supplying raw materials and reducing gas to the reduction part 500. That is, the process S100 of manufacturing reduced iron may include a process of supplying raw materials to the reduction part 500, a process of supplying reducing gas to the reduction part 500, and a process of reducing the raw materials by allowing the raw materials to react with the reducing gas.

[0080] The process of supplying raw materials can be carried out by a raw material supply unit 100, which is configured to supply raw materials to a reduction unit 500 so as to supply raw materials to the reduction unit 500. Here, the raw materials may include iron ore, and the iron ore may include reduced fine iron ore, i.e., powdered iron ore having a particle size greater than about 0 mm and less than or equal to about 8 mm. The process of supplying raw materials may include a process of preheating the raw materials. In an exemplary embodiment, the energy required for reduction may be minimized by supplying and reducing the preheated raw materials (i.e., iron ore).

[0081] The process of supplying the reducing gas may be performed by the reducing gas supply part 200 supplying the reducing gas to the reducing part 500. Here, the reducing gas may include hydrogen, and the hydrogen may be contained in a ratio of about 80% to about 100% of the total reducing gas. The process of supplying the reducing gas may be performed by allowing the reducing gas supply part 200 to supply the reducing gas to the reducing part 500 through the reducing gas supply lines RL1 and RL2 connecting the reducing gas supply part 200 to the reducing part 500. Here, in the process of supplying the reducing gas, the amount of the reducing gas supplied to the reducing part 500 may be controlled within a range of more than 2 times and less than 3 times the amount required to completely reduce the raw material supplied to the reducing part 500.

[0082] In the process of supplying the reducing gas, the reducing gas may be heated to a temperature of about 800° C. to about 1,200° C. and then supplied to the reducing part 500. When hydrogen is used as the reducing gas, reduced iron may be manufactured by allowing the iron ore supplied to the reducing part 500 and the hydrogen to react with each other. Since the reaction between the iron ore and the hydrogen is a strong endothermic reaction, the iron ore supplied to the reducing part 500 may be heated at a temperature of about 800° C. or higher, more preferably about 850° C. or higher, and when the heated reducing gas is supplied, the reduction efficiency may be improved.

[0083] In addition, the process S100 of manufacturing reduced iron may further include a process of supplying a purge gas to the reduction part 500. Here, the process of supplying the purge gas may be performed by a purge gas supply part 400, which is configured to supply the purge gas to the reduction part 500 so as to supply the purge gas to the reduction space through the purge gas supply line PL. Here, an inert gas such as nitrogen may be used as the purge gas.

[0084] In the process of reducing the raw material by allowing the raw material to react with the reducing gas, the reduction part 500 may receive the raw material from the raw material supply part 100, receive the reducing gas from the reducing gas supply part 200, and react the iron ore with the reducing gas to reduce the iron ore. The reduction part 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, but in order to effectively reduce low-grade iron ore or powdered iron ore with a low iron content, a plurality of reduction furnaces may be connected to move the raw material sequentially, thereby manufacturing reduced iron, as described above.

[0085] In the process of reducing the raw material by allowing the raw material to react with the reducing gas, a large amount of by-products may be generated in addition to the reduced iron. The by-products generated and discharged from the reduction section 500 may include water vapor generated by the reaction of the iron ore with the hydrogen, and may also include hydrogen that does not react with the raw material and nitrogen supplied as a purge gas. In addition, dust generated in the reduction section 500 may be included in the by-products and discharged, and the by-products may move along the reducing gas flow in the reduction section 500 and be discharged from the reduction furnace.

[0086] As described above, the by-products discharged from the reduction furnace can be used to generate hydrogen. That is, the method for manufacturing molten iron according to an exemplary embodiment may also include a process of collecting by-products generated in the process of manufacturing reduced iron and a process of extracting hydrogen from the collected by-products. As described above, the by-products discharged from the reduction section 500 may include water vapor, hydrogen, nitrogen and dust, and the reduction section 500 may be provided with an extraction section 600 to receive the by-products discharged from the reduction section 500. Here, the dust may be removed before the by-products are supplied to the extraction section 600 or the dust may be removed in the extraction section 600. The extraction section 600 may extract hydrogen from the by-products supplied through the by-product supply pipeline BL using a pressure swing adsorption method.

[0087] The hydrogen extracted during the process of extracting hydrogen can be used for various purposes. However, the reduction unit 500 can use hydrogen to reduce the raw material (i.e., iron ore), and can use hydrogen in a large amount (twice as much as the amount required to completely reduce the raw material supplied to the reduction unit 500), but hydrogen is a very expensive gas, and therefore, in order to reduce costs through resource recovery, the hydrogen extracted from the extraction unit 600 can be reused as a reducing gas for reducing the iron ore. To this end, the method for manufacturing molten iron according to an exemplary embodiment can be used to reduce the iron ore by supplying the extracted hydrogen as a reducing gas during the process S100 of manufacturing reduced iron. The residue that is not extracted and discharged during the process of extracting hydrogen can be supplied to the reduction unit 500 as a purge gas. As a reaction product produced by the reaction between the iron ore as a raw material and the hydrogen in the reducing gas, the water vapor in the residue can have a low reactivity with the iron ore and the reducing gas, and can therefore be supplied to the reduction unit 500 as a purge gas. Furthermore, when water vapor is supplied as the purge gas to the reduction part 500 , the heat of the water vapor may be used for the reduction reaction to save energy required for the reduction reaction.

[0088] In the process S200 of reacting with the process gas, the reduced iron produced in the reduction part 500 may react with the process gas. Here, the process gas may include a gas containing a carbon component, and the process S200 of reacting with the process gas may include a process of carbonizing at least a portion of the reduced iron produced in the reduction part 500.

[0089] That is, as described above, when the reduced iron manufactured in the reduction part 500 is smelted without any additional treatment, the melting point of the reduced iron may be very high, and thus a large amount of energy may be required to smelt the reduced iron. In contrast, when the reduced iron is carburized, the melting point may be lowered to a temperature of several hundred degrees (° C.) or higher. Therefore, in the method for manufacturing molten iron according to an exemplary embodiment, the reduced iron may react with the process gas, and the reacted reduced iron (i.e., iron carbide) may be supplied to the smelting part 700 for smelting to minimize the amount of energy used for smelting. Here, the process gas may contain a gas containing a carbon component.

[0090] Here, in the process S200 of reacting with the process gas, the reduced iron can react with the process gas without a separate heat treatment. That is, the reduced iron manufactured in the reduction part 500 can be discharged at a high temperature of, for example, about 600°C to about 800°C, and the discharged reduced iron can be directly supplied to the processing part 800 without passing through a separate heat treatment device. In addition, since the high-temperature exhaust gas having a temperature of about 1,200°C or higher is supplied to the processing space, the processing space can maintain a temperature of about 600°C to about 800°C even considering the heat loss of the reduced iron during the transfer process. Therefore, in the process S200 of reacting with the process gas, the manufactured reduced iron can react with the process gas at a temperature of about 600°C to about 800°C, and the processing space can be selectively heated by the heater 820 at the beginning of the process or when additional temperature increase is required.

[0091] When the processing space is maintained at a temperature of about 600° C. to about 800° C., when the partial pressure of carbon monoxide and the partial pressure of carbon dioxide in the processing space specify specific conditions, the reduced iron can be carbonized by reacting according to the above reaction formula. That is, when the exhaust gas and the reduced iron at a high temperature are supplied to the processing space, and the processing space is maintained at a temperature of about 600° C. to about 800° C., when the partial pressure of carbon monoxide Pco is greater than about 90% of the sum of the partial pressure of carbon monoxide Pco and the partial pressure of carbon dioxide Pco2 (Pco+Pco2), the reduced iron can react according to the above reaction formula and be carbonized.

[0092] Here, in order to carbonize the reduced iron by reacting with the treatment gas, the method for manufacturing molten iron according to an exemplary embodiment may include a process S400 of using at least a portion of the exhaust gas generated during the manufacture of the molten material as a treatment gas that reacts with the reduced iron. That is, in the process S400 of using the exhaust gas as the treatment gas, at least a portion of the exhaust gas generated in the process S300 of manufacturing the molten product may be used as a treatment gas that reacts with the reduced iron in the process S200 of allowing the manufactured reduced iron to react with the treatment gas. As described above, the smelting section 700 may include electric furnaces 710 and 720 having a smelting space capable of smelting the reduced iron using electric heating. In the smelting section 700, a recarburizer containing a carbon component may be introduced to adjust the carbon content of the molten product manufactured by smelting the reduced iron. At least a portion of the unreduced raw material (i.e., partially reduced iron or iron ore) may be supplied to the smelting section 700. As described above, at least a portion of the unreduced raw material may have an oxygen component, and the oxygen component may react with the carbon component of the recarburizer in the smelting space. Therefore, in the smelting part 700, exhaust gas containing carbon monoxide gas, that is, exhaust gas having a high carbon monoxide concentration (rich in CO) may be discharged while smelting reduced iron. As described above, the exhaust gas discharged from the smelting part 700 may be discharged at a high temperature of about 1,200°C or more.

[0093] At this time, the smelting part 700 may include electric furnaces 710 and 720 capable of smelting reduced iron, that is, electric smelting furnaces (ESF) or submerged arc furnaces (SAF), which are immersed in slag provided in the electric furnace body 710 to smelt reduced iron with slag resistance heat. As described above, the electric furnaces 710 and 720 may have a very low carbon dioxide content in exhaust gas, and the oxygen component of the unreduced raw material may react with the carbon component of the carburizer, resulting in a high carbon monoxide concentration. Therefore, the partial pressure Pco of carbon monoxide discharged from the electric furnaces 710 and 720 may be about 90% or more of the sum (Pco+Pco2) of the partial pressure Pco of carbon monoxide and the partial pressure Pco2 of carbon dioxide, and therefore, the reduced iron may be effectively carbonized under a temperature condition of about 600° C. to about 800° C.

[0094] In the process S200 of reacting with the treatment gas, a supplementary gas having at least a portion of the same components as the exhaust gas may be used as the treatment gas. As described above, the supplementary gas supply part 900 may supply the supplementary gas, i.e., the carbon-containing gas having at least some of the same components as the exhaust gas, to the treatment part 800, and the supplementary gas supply part 900 may supply the carbon-containing gas to the treatment part 800 through the supplementary gas supply line SL. Here, the supplementary gas supply line SL may be connected to the exhaust gas supply line EL to supply the supplementary gas and the exhaust gas together, and the supplementary gas may include at least one of a natural gas containing carbon or a biomass gas obtained by gasifying biomass.

[0095] Here, most of the reduced iron supplied to the processing space in the process S200 of reacting with the processing gas may react with the exhaust gas and be supplied to the smelting part 700, but the reduced iron in the reduced fine iron may not fully react with the exhaust gas, but flow through the exhaust gas and then be discharged to the outside of the processing space together with the exhaust gas.

[0096] Therefore, the method for manufacturing molten iron according to an exemplary embodiment may further include a process of collecting reduced iron discharged from a process space in which the reduced iron reacts with the process gas and a process of supplying the collected reduced iron to the process space.

[0097] Here, the process of collecting the discharged reduced iron may be performed by a collector 840 connected to the main body 810 to collect the reduced iron discharged from the main body 810, and the collector 840 may be connected to the upper portion of the main body 810, and thus connected to the exhaust pipe XL through which the exhaust gas is discharged. In addition, in the process of supplying the collected reduced iron to the processing space, the reduced fine iron collected by the collector 840 may be resupplied to the processing space of the main body 810 through the circulation line CL. Here, the circulation line CL may be directly connected to the processing space, but may also be connected to the above-mentioned reduced iron supply pipe FL, so that the reduced fine iron collected by the collector 840 is resupplied to the processing space of the main body 810.

[0098] The process S300 of manufacturing a molten product can be performed by a smelting part 700 that receives the reacted reduced iron (i.e., iron carbide) from the processing part 800 to smelt the supplied iron carbide. That is, the smelting part 700 can receive fine or compacted iron carbide from the processing part 800 to heat and smelt the reduced iron. In addition, the process S300 of manufacturing a molten product can be performed by a smelting part 700 that receives iron carbide from the reduction part 800 to smelt the supplied reduced iron using electric heating. Here, the smelting part 700 may include an electric furnace having a smelting space capable of using electric heating to smelt iron carbide. Such an electric furnace may include an electric furnace body having a smelting space and an electrode rod, at least a portion of the electrode rod is arranged in the smelting space to generate electric heating, and when the reduced iron is charged into the smelting space, the smelting part 700 may provide power to the electrode rod, thereby smelting the iron carbide.

[0099] Here, the process S300 of manufacturing a molten product may include a process of placing a carburizer in the smelting section 700 (i.e., the smelting space of the electric furnace). In the smelting section 700, a carburizer containing a carbon component is introduced to adjust the carbon content of the melt produced by smelting reduced iron. In addition, the carburizer may be added to produce a large amount of slag when smelting the molten product. The electrode rod 720 may generate resistance heat by immersing in the slag, and iron carbide may be more easily smelted by the resistance heat generated. Here, since the iron carbide supplied by the processing section 800 already contains a large amount of carbon components, the amount of the carburizer used may be minimized in the process S300 of manufacturing a molten product.

[0100] As described above, in the smelting part 700, exhaust gas containing carbon monoxide gas, that is, exhaust gas having a high carbon monoxide concentration (rich in CO) and a temperature of about 1,200° C. or higher, may be discharged while smelting reduced iron. Therefore, the exhaust gas discharged from the smelting part 700, that is, the exhaust gas discharged during the process of manufacturing a molten product, may be used to perform the above-mentioned process of preheating the raw material, which will be described later. Since the exhaust gas discharged from the smelting part 700 is discharged at a high temperature of about 1,200° C. or higher, the raw material may be preheated by using the heat energy of the exhaust gas.

[0101] To explain this in more detail, the process of preheating the raw material may include a process of directly injecting a portion of the exhaust gas discharged from the smelting part 600 onto the raw material. In the process of supplying the raw material, the raw material stored in the storage space of the storage tank 110 may be supplied to the reduction part 500. Therefore, the preheating gas supply part 120 may be installed in the storage tank 110 to supply the preheating gas to the storage space of the storage tank 110. Here, the process of preheating the raw material may be performed by injecting high-temperature exhaust gas having a temperature of about 1,200°C or higher from the preheating gas supply part 120 into the raw material stored in the storage space. In addition, the preheating gas supply part 120 may inject heated external air into the raw material stored in the storage space to preheat the raw material. Here, in the process of preheating the raw material, the preheating gas supply part 120 may heat the external air using the heat of the exhaust gas having a temperature of about 1,200°C or higher, and may supply the heated air to the storage space to preheat the raw material.

[0102] As described above, the melting point of the reduced iron can be lowered by allowing the exhaust gas generated in the process to react with the reduced iron, thereby minimizing the amount of energy used to smelt the reduced iron.

[0103] Furthermore, reduced iron manufactured at high temperature can directly react with high-temperature exhaust gas to minimize facilities and resources required for the reaction.

[0104] Furthermore, energy can be efficiently collected by utilizing the sensible heat of high-temperature exhaust gas to preheat the raw material and generate hydrogen.

[0105] Although specific embodiments are described and illustrated by using specific terms, the terms are only used to clearly illustrate examples of the embodiments, and therefore, it is obvious to those skilled in the art that the embodiments and technical terms can be implemented in other specific forms and changes without changing the technical concept or basic features. Therefore, it should be understood that simple modifications of the embodiments according to the present invention can belong to the technical spirit of the present invention.

Claims

1. A facility for producing molten iron, the facility comprising: a reduction section configured to produce reduced iron; a smelting part configured to smelt the reduced iron; and A processing part is configured to receive the reduced iron from the reducing part and the exhaust gas discharged from the smelting part so that the supplied reduced iron and the exhaust gas react with each other to supply the reacted reduced iron to the smelting part.

2. The facility according to claim 1, further comprising an exhaust gas supply line arranged to be connected to the smelting section and the processing section, wherein the reducing part includes a reducing furnace having a reducing space in which a reducing gas is supplied to produce the reduced iron, and The smelting part includes an electric furnace having a smelting space in which electric heating is used to smelt the reduced iron supplied from the processing part.

3. The facility of claim 2, wherein the processing section comprises: A subject with a processing space; a reduced iron inlet provided in the body to allow the reduced iron to flow into the processing space; and an exhaust gas inlet, which is provided in the main body and connected to an exhaust gas supply line so that the exhaust gas is introduced into the processing space, The exhaust gas inlet is arranged at a position lower than the reduced iron inlet. 4 . The facility of claim 3 , wherein the processing section further comprises a heater installed in the main body to heat the processing space.

5. The facility of claim 3, wherein the processing section comprises: a collector connected to the main body to collect the reduced iron discharged from the main body; and A circulation line is configured to connect the collector and the main body so that the reduced iron collected by the collector is supplied to the main body. 6 . The facility according to claim 3 , wherein the processing section further comprises a supplementary gas supply section connected to the main body so as to supply a supplementary gas having at least a portion of the same component as the exhaust gas to the processing space.

7. The facility of claim 2, further comprising: a raw material supply part having a storage space in which a raw material is stored and configured to supply the raw material stored in the storage space to the reduction space; and an exhaust gas branch line that branches from the exhaust gas supply line and is configured to supply a portion of the exhaust gas exhausted from the electric furnace to the raw material supply portion. 8 . The facility according to claim 7 , wherein the exhaust gas branch line is connected to the raw material supply part to directly supply the exhaust gas to the storage space or transfer heat of the exhaust gas to air supplied to the storage space.

9. The facility of claim 3, further comprising: a purge gas supply line connected to the reduction furnace to supply a purge gas to the reduction space; and A purge gas branch line is branched from the purge gas supply line and is configured to supply a portion of the purge gas supplied to the reduction space to the processing space.

10. A method for producing molten iron, the method comprising: Manufacturing reduced iron; Allowing the produced reduced iron to react with the process gas; smelting the reduced iron to produce a molten product; as well as At least a portion of the exhaust gas generated when the molten iron is produced is used as a process gas that reacts with the reduced iron.

11. The method according to claim 10, wherein producing the reduced iron comprises: Using the waste gas to preheat the raw materials; as well as The preheated raw material is allowed to react with the reducing gas to reduce the raw material. 12 . The method of claim 11 , wherein preheating the feedstock comprises injecting the exhaust gas into the feedstock or receiving heat of the exhaust gas to inject heated air into the feedstock.

13. The method of claim 11, wherein the feedstock comprises powdered iron ore having a particle size greater than about 0 mm and less than or equal to about 8 mm.

14. The method of claim 10, wherein the process gas comprises a gas containing a carbon component, and Reacting with the process gas includes carburizing at least a portion of the reduced iron.

15. The method of claim 10, wherein allowing the reduced iron to react with the process gas comprises reacting with the process gas without performing a separate heat treatment on the produced reduced iron.

16. The method of claim 10, wherein allowing the reduced iron to react with the process gas comprises allowing the produced reduced iron to react with the process gas at a temperature of about 600°C to about 800°C.

17. The method according to claim 10, further comprising: collecting the reduced iron discharged from the processing space where the reduced iron reacts with the processing gas; as well as The collected reduced iron is supplied to the processing space.

18. The method according to claim 17, wherein producing the molten iron includes supplying a purge gas to a reduction space in which the reduced iron is produced, and Allowing the reduced iron to react with the process gas includes supplying a portion of the purge gas supplied to the reduction space to the process space.

19. The method of claim 10, wherein utilizing at least a portion of the exhaust gas as the process gas comprises utilizing the exhaust gas and a make-up gas having at least a portion of the same composition as the exhaust gas as the process gas.

20. The method of claim 19, wherein the exhaust gas comprises carbon monoxide gas, and The supplemental gas includes at least one of natural gas or biomass gas.

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