Apparatus for manufacturing molten iron and method for manufacturing molten iron

Abstract

The present invention provides a molten iron manufacturing facility for producing molten iron using raw materials containing iron and coke, comprising: a device for producing a lump body containing iron carbide using reduced iron; a melting device installed to receive said raw materials, coke, and lump body so as to melt said raw materials and lump body to produce molten iron; and a method for producing molten iron using the same, wherein the molten iron manufacturing facility and the method for producing molten iron can improve reduction efficiency and reduce the generation of environmental pollutants.

Description

Technology Field

[0001] The present invention relates to a molten iron manufacturing facility and a method for manufacturing molten iron, and more specifically, to a molten iron manufacturing facility and a method for manufacturing molten iron capable of improving reduction efficiency and reducing the generation of environmental pollutants. Background Technology

[0003] Recently, environmental regulations aimed at reducing carbon dioxide emissions have been strengthened both domestically and internationally. As the steel industry is also required to reduce carbon dioxide emissions, research to reduce emissions is actively underway.

[0004] As part of research aimed at reducing carbon dioxide emissions, various technologies are being developed to replace some existing carbon-based reducing agents with hydrogen. Using hydrogen as a reducing agent instead of conventional carbon-based agents offers the advantages of producing water instead of carbon dioxide as the emission after reduction, as well as a faster reduction rate compared to existing methods.

[0005] Meanwhile, regarding blast furnace equipment, which has been used as the primary device in the molten iron manufacturing process, methods to replace a portion of the existing carbon-based reducing agent with hydrogen include supplying hydrogen or hydrogen-containing gas along with hot air to tuyeres located at the bottom of the furnace, or supplying hydrogen or hydrogen-containing gas to a separate inlet located at the top of the furnace. However, among these methods, the method of supplying hydrogen or hydrogen-containing gas to a separate inlet located at the top of the furnace presents a problem in that it is difficult to smoothly supply hydrogen to the center of the furnace due to the significantly high internal pressure.

[0006] The technology forming the background of the present invention is disclosed in the following patent documents. Prior art literature

[0007] (Patent Document 0001) KR 10-0864459 B1 The problem to be solved

[0008] The present invention provides a molten iron manufacturing facility and a method for manufacturing molten iron that can improve reduction efficiency and reduce the generation of environmental pollutants. means of solving the problem

[0009] A molten iron manufacturing apparatus according to an embodiment of the present invention is a molten iron manufacturing facility that manufactures molten iron using a raw material containing an iron source and coke, and comprises: a mass manufacturing apparatus capable of manufacturing a mass containing iron carbide using reduced iron; and a melting apparatus installed to receive the raw material, coke, and mass so as to reduce and melt the raw material and mass to manufacture molten iron.

[0010] It may include a gas synthesis device connected to the melting device to allow exhaust gas discharged from the melting device to flow in, and connected to the agglomerate manufacturing device to deliver methane-containing gas produced from the exhaust gas.

[0011] It may include a gas supply device that can be connected to the coke manufacturing device, the agglomerate manufacturing device, and the melting device so as to divide and supply the hydrogen-containing flue gas discharged from the coke manufacturing device for manufacturing coke to the agglomerate manufacturing device and the melting device.

[0012] The above-mentioned agglomerate manufacturing device may be connected to at least one of the coke manufacturing device and the melting device so as to receive at least one by-product among the first carbon material by-product discharged from the coke manufacturing device and the second carbon material by-product discharged from the melting device.

[0013] The above-described agglomerate manufacturing device may include: an iron carbide manufacturing unit installed to receive reduced iron and connected to the gas synthesis device, capable of producing iron carbide by reacting the reduced iron with a hydrogen-containing gas and a methane-containing gas; and a molding unit installed to receive the iron carbide, mold the iron carbide into the agglomerate, and supply the agglomerate to the melting device.

[0014] A reduced iron manufacturing device is installed to receive a reduced iron raw material containing iron ore, can be connected to the coke manufacturing device, and can reduce the reduced iron raw material with a hydrogen-containing gas to produce the reduced iron; and the agglomerate manufacturing device can be installed to receive the reduced iron from the reduced iron manufacturing device.

[0015] The above-described agglomerate manufacturing device may receive and store at least one of the first carbon material byproduct discharged from the coke manufacturing device and the second carbon material byproduct discharged from the melting device, and may further include a byproduct supply unit connected to the molding unit.

[0016] The above gas synthesis device may include: a first carbon dioxide separation unit that separates exhaust gas discharged from the melting device according to carbon dioxide content; a hydrogen separation unit that separates gas supplied from the first carbon dioxide separation unit according to hydrogen concentration; and a methane-containing gas production unit that reacts the gas supplied from the first carbon dioxide separation unit and the hydrogen separation unit and supplies the synthesized gas to the iron carbide production unit.

[0017] The above gas synthesis device may include a second carbon dioxide separation unit installed to receive exhaust gas discharged from a reduced iron manufacturing device for producing reduced iron, and to separate the exhaust gas according to carbon dioxide concentration and supply it separately to the iron carbide manufacturing unit and the gas synthesis device.

[0018] A method for manufacturing molten iron according to an embodiment of the present invention comprises: a process of preparing a raw material containing an iron source; a process of preparing coke; a process of manufacturing an agglomerate containing iron carbide using reduced iron; and a process of introducing the raw material, the coke, and the agglomerate into a melting device and melting them.

[0019] The process of preparing the reduced iron is further included; and the process of manufacturing the agglomerate may include: a process of receiving the reduced iron; a process of preparing a methane-containing gas; a process of preparing a hydrogen-containing gas; a process of producing the iron carbide by flowing the reduced iron and reacting it with the hydrogen-containing gas and the methane-containing gas; and a process of molding the iron carbide to form an agglomerate shape.

[0020] As the hydrogen-containing gas used to manufacture the above iron carbide, at least one of the gas from which carbon dioxide has been removed from the flue gas containing hydrogen generated during the production of reduced iron and the flue gas containing hydrogen generated during the production of coke may be used.

[0021] The process of preparing the reduced iron may include: a process of preparing a hydrogen-containing gas; and a process of producing the reduced iron by flowing a reduced iron raw material containing iron ore through the hydrogen-containing gas and reacting it with the hydrogen-containing gas.

[0022] The process of preparing the above hydrogen-containing gas may include a process of receiving exhaust gas containing hydrogen that is generated during the process of preparing the above coke.

[0023] The process of preparing the methane-containing gas may include: a process of separating the exhaust gas discharged from the melting device into a high-concentration carbon dioxide-containing gas and a low-concentration carbon dioxide-containing gas having a lower carbon dioxide content than the high-concentration carbon dioxide-containing gas by utilizing a pressure difference; a process of separating the low-concentration carbon dioxide-containing gas into a high-concentration hydrogen-containing gas and a low-concentration hydrogen-containing gas having a lower hydrogen content than the high-concentration hydrogen-containing gas by utilizing a pressure difference; and a process of synthesizing the methane-containing gas by mixing and heating the high-concentration hydrogen-containing gas and the high-concentration carbon dioxide-containing gas.

[0024] The process may include providing the high-concentration hydrogen-containing gas generated during the process of preparing the methane-containing gas to the melting device.

[0025] The process of manufacturing the above-mentioned agglomerate includes a process of providing exhaust gas discharged during the process of manufacturing the above-mentioned iron carbide so that it can be utilized in at least one of the process of preparing the above-mentioned reduced iron and the process of melting it; and the process of preparing the above-mentioned reduced iron may include a process of separating the exhaust gas discharged during the preparation of the above-mentioned reduced iron into high carbon dioxide content gas and low carbon dioxide content gas according to carbon dioxide content using a pressure difference; and a process of providing the low carbon dioxide content gas so that it can be utilized in the process of manufacturing the above-mentioned iron carbide and providing the high carbon dioxide content gas so that it can be utilized in the process of preparing the above-mentioned methane content gas.

[0026] The process of forming the iron carbide may include: a process of receiving at least one of a first carbon material byproduct generated during the process of preparing the coke and a second carbon material byproduct generated from the melting device; a process of mixing the iron carbide with at least one of the first carbon material byproduct and the second carbon material byproduct to produce a mixture; and a process of pressing the mixture. Effects of the invention

[0027] According to an embodiment of the present invention, by using reduced iron to produce an agglomerated body containing iron carbide and introducing the agglomerated body into a melting device to produce molten iron, the reduction efficiency within the melting device can be improved, and consequently, the amount of coke used as a reducing agent can be reduced. Therefore, the amount of coke input for the production of molten iron can be reduced. Furthermore, by reducing the amount of coke, the generation of carbon dioxide originating from the coke can be reduced. Consequently, the exacerbation of atmospheric pollution caused by carbon dioxide can be suppressed or prevented. Brief explanation of the drawing

[0029] FIG. 1 is a block diagram conceptually illustrating a molten iron manufacturing facility according to an embodiment of the present invention. Figure 2 is a graph showing the results of predicting the reduction rate in a blast furnace for reduced iron according to a comparative example of the present invention. FIG. 3 is a conceptual diagram for explaining blast furnace operation according to an embodiment of the present invention. Figure 4 is a graph showing the carbon content according to the manufacturing temperature of iron carbide manufactured according to an embodiment of the present invention. Specific details for implementing the invention

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. The embodiments of the present invention are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. To illustrate the embodiments of the present invention, the drawings may be exaggerated, and like reference numerals in the drawings refer to like elements.

[0031] The present invention relates to a molten iron manufacturing facility and a method for manufacturing molten iron. Below, embodiments of the present invention will be described in detail by exemplifying cases where the molten iron manufacturing facility and the method for manufacturing molten iron are applied to blast furnace operations during the steel manufacturing process.

[0032] Before describing the molten iron manufacturing facility and the method for manufacturing molten iron according to an embodiment of the present invention, the raw materials, coke, and reduced iron supplied to the molten iron manufacturing facility according to an embodiment of the present invention are briefly described.

[0033] The raw materials may include sintered ore. The sintered ore may be produced in a continuous sintering furnace of a sintered ore manufacturing device (1100). The coke may be produced in a coke oven of a coke manufacturing device (1200) and quenched in a coke dry quencher. The reduced iron may be produced in a fluidized reduction furnace of a reduced iron manufacturing device (1300) (see FIG. 1). The sintered ore and coke may be supplied to a melting device (5000) of a molten iron manufacturing facility according to an embodiment of the present invention. The reduced iron may be in powder form and may be supplied to an agglomerate manufacturing device (2000) of a molten iron manufacturing facility according to an embodiment of the present invention.

[0035] FIG. 1 is a conceptual block diagram illustrating a molten iron manufacturing facility according to an embodiment of the present invention. Hereinafter, a molten iron manufacturing facility according to an embodiment of the present invention will be described in detail with reference to FIG. 1.

[0036] Referring to FIG. 1, a molten iron manufacturing facility according to an embodiment of the present invention manufactures molten iron using raw materials containing iron source and coke, and includes a mass manufacturing device (2000) capable of manufacturing a mass containing iron carbide using reduced iron, and a melting device (5000) installed to receive raw materials, coke and masses so as to reduce and melt the raw materials and masses to manufacture molten iron.

[0037] In addition, the molten iron manufacturing facility according to an embodiment of the present invention may include a gas synthesis device (4000) connected to a melting device (5000) so that exhaust gas (referred to as exhaust gas (EG4) of the melting device) discharged from the melting device (5000) is introduced, and connected to a mass manufacturing device (2000) so that a methane-containing gas (MG) produced from the exhaust gas (EG4) of the melting device can be delivered.

[0038] In addition, the molten iron manufacturing facility according to an embodiment of the present invention may include a gas supply device (3000) that can be connected to a coke manufacturing device (1200), a lump manufacturing device (2000), and a melting device (5000) so as to be able to supply flue gas (hereinafter referred to as flue gas (EG2) of the coke manufacturing device) that is discharged from a coke manufacturing device (1200) and contains hydrogen to a lump manufacturing device (2000) and a melting device (5000) by dividing and supplying them.

[0040] At this time, the molten iron manufacturing facility according to the embodiment of the present invention may use sintered ore, coke, and reduced iron produced in a separate sintered ore manufacturing device (1100), coke manufacturing device (1200), and reduced iron manufacturing device (1300).

[0041] That is, the molten iron manufacturing facility according to the embodiment of the present invention may receive raw materials such as sintered ore from outside the molten iron manufacturing facility instead of including a sintered ore manufacturing device (1100).

[0042] Likewise, the molten iron manufacturing facility according to an embodiment of the present invention may receive coke, reduced iron, flue gas (EG2) from the coke manufacturing facility, a first carbon material byproduct, and flue gas (EG1) from the reduced iron manufacturing facility instead of including a coke manufacturing device (1200) and a reduced iron manufacturing device (1300).

[0044] Of course, the molten iron manufacturing facility according to an embodiment of the present invention may further include a sintered ore manufacturing device (1100), a coke manufacturing device (1200), and a reduced iron manufacturing device (1300).

[0045] Meanwhile, to facilitate understanding of the embodiments of the present invention, the embodiments will be described by exemplifying that the molten iron manufacturing facility according to the embodiments of the present invention includes a sintered ore manufacturing device (1100), a coke manufacturing device (1200), and a reduced iron manufacturing device (1300).

[0047] The sintered ore manufacturing device (1100) may include a continuous sintering machine. The continuous sintering machine may be installed to circulate a sintering trolley and sinter iron ore to produce sintered ore. The coke manufacturing device (1200) may include a coke oven and a coke dry extinguisher. The coke oven may be installed to charge coal, i.e., bituminous coal, into a carbonization chamber and carbonize it at a high temperature to produce coke. The coke dry extinguisher may be installed to receive high-temperature coke extruded from the carbonization chamber of the coke oven. Additionally, the coke dry extinguisher may cool the coke by passing gas through the received coke.

[0048] The reduced iron manufacturing device (1300) may be installed to receive a reduced iron raw material containing iron ore powder. Additionally, the reduced iron manufacturing device (1300) may be connected to a coke manufacturing device (1200). Furthermore, the reduced iron manufacturing device (1300) may include one or more fluidized reduction furnaces installed to produce reduced iron by flowing the reduced iron raw material through a hydrogen-containing gas and reducing it with the hydrogen-containing gas.

[0050] The agglomerate manufacturing device (2000) serves to manufacture an agglomerate containing iron carbide using reduced iron. To this end, the agglomerate manufacturing device (2000) may include an iron carbide manufacturing section (2100) and a molding section (2200). Additionally, the agglomerate manufacturing device (2000) may further include a byproduct supply section (2300). Furthermore, the agglomerate manufacturing device (2000) may be installed to receive reduced iron from the reduced iron manufacturing device (1300). Additionally, the agglomerate manufacturing device (2000) may be installed to supply the agglomerate to a melting device (5000).

[0051] The iron carbide manufacturing unit (2100) can receive reduced iron and manufacture iron carbide. Additionally, the iron carbide manufacturing unit (2100) can provide exhaust gas (EG3) from the iron carbide manufacturing unit. To this end, the iron carbide manufacturing unit (2100) can be installed to receive reduced iron. At this time, the reduced iron may be manufactured by the reduced iron manufacturing device (1300). Additionally, the iron carbide manufacturing unit (2100) can be installed to provide exhaust gas (EG3) from the iron carbide manufacturing unit. Here, the exhaust gas (EG3) from the iron carbide manufacturing unit can be provided to the reduced iron manufacturing device (1300). Here, being installed to receive reduced iron means being installed in various structures within the range that satisfies the condition of being able to receive reduced iron. That is, the iron carbide manufacturing unit (2100) may be installed in any structure as long as it is capable of receiving reduced iron. For example, the iron carbide manufacturing unit (2100) may be installed to have a reduced iron inlet formed to receive reduced iron. Likewise, the iron carbide manufacturing unit (2100) may be installed to have a gas outlet formed to provide exhaust gas (EG3) from the iron carbide manufacturing unit.

[0052] Additionally, the iron carbide manufacturing unit (2100) may be connected to the gas synthesis device (4000). More specifically, the iron carbide manufacturing unit (2100) may be connected to the second carbon dioxide separation unit (4300) and the methane-containing gas manufacturing unit (4400) of the gas synthesis device (4000). Accordingly, piping may be installed to connect the iron carbide manufacturing unit (2100) and the second carbon dioxide separation unit (4300), and likewise, piping may be installed to connect the iron carbide manufacturing unit (2100) and the methane-containing gas manufacturing unit (4400). Low carbon dioxide-containing gas (CLG1) may be supplied from the iron carbide manufacturing unit (2100) and the second carbon dioxide separation unit (4300), and methane-containing gas (MG) may be supplied from the methane-containing gas manufacturing unit (4400).

[0053] Additionally, the iron carbide manufacturing unit (2100) may be connected to a melting device (5000). More specifically, the iron carbide manufacturing unit (2100) may be connected to the tuyere of the melting device (5000), for example, via piping. At this time, the iron carbide manufacturing unit (2100) may supply exhaust gas (EG3) from the iron carbide manufacturing unit to the melting device (5000).

[0054] The iron carbide manufacturing unit (2100) may include a fluidized carbonization furnace that produces iron carbide by fluidizing reduced iron and reacting it with methane-containing gas (MG) and hydrogen-containing gas. The fluidized carbonization furnace may be provided as a single furnace, or multiple furnaces may be provided and connected in sequence.

[0055] A fluidized carbonization furnace may include a vessel having an internal space (carbonization space) capable of carbonizing reduced iron, and a dispersion member disposed inside the vessel having a plurality of holes capable of passing methane-containing gas (MG) and hydrogen-containing gas. Additionally, the fluidized carbonization furnace may further include a cyclone, at least a portion of which is located inside the vessel and which collects fine particles, and a burner that generates a flame into the vessel. Of course, the configuration of the fluidized carbonization furnace and the method of manufacturing iron carbide may vary.

[0056] The molding section (2200) can receive iron carbide and mold the iron carbide into a mass. Additionally, the molding section (2200) can supply the mass to the melting device (5000). To this end, the molding section (2200) can be installed to receive iron carbide. Likewise, the molding section (2200) can be installed to mold the iron carbide into a mass and to supply the mass to the melting device (5000).

[0057] For example, the molding section (2200) may be installed to have an iron carbide inlet so as to receive iron carbide. Additionally, the molding section (2200) may include a hopper connected to the iron carbide inlet, a pair of rolls arranged to face each other at the lower side of the hopper, a molding member installed on the outer surface of each of the pair of rolls and having a die formed at multiple locations on the outer surface, and a housing in which a pair of rolls are installed inside and a hopper is installed on the upper side. Additionally, the molding section (2200) may be installed to have a mass discharge section so as to discharge a mass. The mass discharge section may be formed in the housing.

[0058] The molding unit (2200) can form a mass, for example, by a compression method. Specifically, the molding unit (2200) rotates a pair of rolls and feeds iron carbide or a mixture described later between the pair of rolls to fill each of the molding member's cavities, and can manufacture a mass by using the rotation of the rolls to compress the iron carbide or mixture inside each cavity. The mass is discharged to the lower side of the pair of rolls and can be discharged to the outside of the molding unit (2200) through the mass discharge end. At this time, the mixture may be a mixture of iron carbide and a carbon material byproduct described later supplied from the byproduct supply unit (2300).

[0059] Of course, the structure and operation method of the molding unit (2200) may vary. As long as the molding unit (2200) has a structure and operation method capable of receiving iron carbide, molding the iron carbide into a lump, and supplying the lump to the melting device (5000), it may be installed in any structure and may be operated in any operation method.

[0060] The byproduct supply unit (2300) can receive and store at least one of the first carbon material byproduct discharged from the coke manufacturing device (1200) and the second carbon material byproduct discharged from the melting device (5000). Additionally, the byproduct supply unit (2300) can supply at least one of the first carbon material byproduct and the second carbon material byproduct to the molding unit (2200). To this end, the byproduct supply unit (2300) can be installed to receive and store at least one of the first carbon material byproduct and the second carbon material byproduct. Additionally, the byproduct supply unit (2300) can be connected to the molding unit (2200). For example, a belt conveyor can be installed to connect the byproduct supply unit (2300) and the molding unit (2200). Of course, the structure in which the byproduct supply unit (2300) connects to the molding unit (2200) can be diverse, including chutes, pipes, etc. Meanwhile, the byproduct supply unit (2300) may be connected to a coke manufacturing device (1200) or to a melting device (5000).

[0061] The first carbon material byproduct may include coke dust. Additionally, the first carbon material byproduct may be discharged from the Coke Dry Quenching of the coke manufacturing device (1200). The second carbon material byproduct may include blast furnace dust. Additionally, the second carbon material byproduct may be discharged from the melting device (5000). These carbon material mixtures may be supplied to the hopper of the molding section (2200) and mixed with iron carbide. Additionally, the mixture of iron carbide and carbon material byproducts may be hot or cold pressed by a pair of rolls and a molding member of the molding section (2200) to form an agglomerate.

[0062] The gas supply device (3000) serves to divide and supply the exhaust gas (EG2) from the coke manufacturing device to the lump body manufacturing device (2000) and the melting device (5000). Additionally, the gas supply device (3000) serves to receive methane-containing gas (MG) from the gas synthesis device (4000) and supply it to the melting device (5000). To this end, the gas supply device (3000) can be installed to receive the exhaust gas (EG2) from the coke manufacturing device. Furthermore, the gas supply device (3000) can be connected to the melting device (5000) and to the gas synthesis device (4000). Additionally, the gas supply device (3000) may include a branching section (3100), a compression section (3200), and a buffer section (3300).

[0063] The branching section (3100) serves to branch the exhaust gas (EG2) of the coke manufacturing device. The branching section (3100) may include a transfer pipe through which the exhaust gas (EG2) of the coke manufacturing device can pass. At this time, the inlet end of the transfer pipe may be installed to receive the exhaust gas (EG2) of the coke manufacturing device from the coke manufacturing device (1200). The outlet end of the transfer pipe may be branched into multiple parts. Additionally, one of the multiple outlet ends of the transfer pipe may be installed to provide a portion of the exhaust gas (EG2) of the coke manufacturing device to the reduced iron manufacturing device (1300). Additionally, another of the multiple outlet ends of the transfer pipe may be installed to provide a portion of the exhaust gas (EG2) of the coke manufacturing device to the iron carbide manufacturing unit (2100). Additionally, the remaining one of the multiple discharge ends of the transfer pipe may be connected to the compression unit (3200) to provide the remainder of the exhaust gas (EG2) of the coke manufacturing device to the compression unit (3200). Meanwhile, the inlet and discharge ends of the transfer pipe may also be referred to as the inlet and discharge ends of the branching unit (3100).

[0064] The compression unit (3200) serves to pressurize the exhaust gas (EG2) of the coke manufacturing device supplied to the melting device (5000) at a pressure higher than the pressure. To this end, the compression unit (3200) may be connected to the remaining one of the multiple discharge ends of the branching unit (3100). Additionally, the compression unit (3200) may be connected to the buffer unit (3300). That is, a connecting pipe may be installed to connect the compression unit (3200) and the buffer unit (3300).

[0065] Additionally, the compression unit (3200) may include a compressor connected to the discharge end of the branch unit (3100), a compression tank connected to the compressor, a connecting pipe installed to connect the compression tank and the buffer unit (3300), and a plurality of valves installed respectively in the compressor, the compression tank, and the connecting pipe. The compression unit (3200) may further include a dust collector. The dust collector may have various configurations, such as a scrubber or a filter. The dust collector may be installed between the compressor and the discharge end of the branch unit (3100). The dust collector can remove dust from the exhaust gas (EG2) of the coke manufacturing device before the compressor compresses the exhaust gas (EG2) of the coke manufacturing device. Of course, the configuration of the compression unit (3200) may vary. Meanwhile, a gas synthesis device (4000) may be connected to the connecting pipe. Additionally, the methane-containing gas (MG) discharged from the gas synthesis device (4000) may be supplied to the buffer unit (3300) through the connecting pipe.

[0066] The buffer section (3300) acts as a buffer to cushion the pressure difference between the compression section (3300) and the melting device (5000). The buffer section (3300) can be connected to the connecting pipe of the compression section (3200). Additionally, the buffer section (3300) can be connected to the tuyere of the melting device (5000). For example, a buffer pipe may be installed to connect the buffer section (3300) and the tuyere of the melting device (5000). The buffer section (3300) may be a type of pressure tank installed to cushion shocks by adjusting its internal volume according to changes in the pressure of the incoming and outgoing gas.

[0067] The exhaust gas (EG2) of the coke manufacturing device is supplied to the branching section (3100), and a portion of it can be supplied to the reduced iron manufacturing device (1300) and the iron carbide manufacturing section (2100), respectively. The remainder can be pressurized in the compression section (3200) and supplied to the buffer section (3300), and after being mixed with methane-containing gas (MG) in the buffer section (3300), it can be supplied to the tuyere of the melting device (5000).

[0068] The gas synthesis device (4000) serves to synthesize methane-containing gas (MG) from the exhaust gas (EG4) of the melting device. Additionally, the gas synthesis device (4000) serves to supply a portion of the methane-containing gas (MG) to the iron carbide manufacturing section (2100) of the agglomerate manufacturing device (2000), and to supply the remainder of the methane-containing gas (MG) to the buffer section (3300) of the gas supply device (3000). Furthermore, the gas synthesis device (4000) serves to supply high-concentration hydrogen-containing gas (HHG1), which is generated during the series of processes for synthesizing the methane-containing gas (MG), to the melting device (5000). Accordingly, the gas synthesis device (4000) can be connected to the melting device (5000) and the gas supply device (3000), respectively. Additionally, the gas synthesis device (4000) may be installed to supply methane-containing gas (MG) and low carbon dioxide-containing gas (CLG1), respectively, to the iron carbide manufacturing unit (2100) of the agglomerate manufacturing device (2000). Additionally, the gas synthesis device (4000) may be installed to receive exhaust gas (EG1) from the reduced iron manufacturing device (1300). Furthermore, the gas synthesis device (4000) may include a first carbon dioxide separation unit (4100), a hydrogen separation unit (4200), a second carbon dioxide separation unit (4300), and a methane-containing gas manufacturing unit (4400).

[0069] The first carbon dioxide separation unit (4100) has the role of separating the exhaust gas (referred to as the exhaust gas of the melting unit (EG4)) discharged from the melting device (5000) according to the carbon dioxide content, and supplying the gas separated according to the carbon dioxide content to the hydrogen separation unit (4200) and the methane-containing gas production unit (4400), respectively.

[0070] The first carbon dioxide separation unit (4100) may be connected to the melting device (5000) so that the exhaust gas (EG4) of the melting device is introduced. Additionally, the first carbon dioxide separation unit (4100) may be connected to the methane-containing gas manufacturing unit (4400) to supply the high-concentration carbon dioxide-containing gas (CHG2) among the separated gases according to the carbon dioxide content to the methane-containing gas manufacturing unit (4400), and may be connected to the hydrogen separation unit (4200) to supply the low-concentration carbon dioxide-containing gas (CLG2) to the hydrogen separation unit (4200).

[0071] The first carbon dioxide separation unit (4100) may be a means for separating a specific component in a gas using a pressure difference. In this case, the pressure difference refers to the difference in pressure at which each component of the gas can be adsorbed. That is, the adsorption of each component contained in the gas to an adsorbent may vary depending on the pressure of the gas. Accordingly, the first carbon dioxide separation unit (4100) can separate the components contained in the gas by utilizing this difference in pressure at which each component of the gas can be adsorbed.

[0072] More specifically, the first carbon dioxide separation unit (4100) may be a means for separating carbon dioxide from the flue gas (EG4) of a melting device, for example, by a pressure swing adsorption (PSA) method. To this end, the first carbon dioxide separation unit (4100) may include a plurality of separation towers and an adsorbent, such as a carbon molecular sieve (CMS), which is mounted on each separation tower and has porous particles capable of selectively adsorbing gas according to pressure.

[0073] The first carbon dioxide separation unit (4100) can repeatedly perform operations such as pressurizing the exhaust gas (EG4) of a melting device introduced into the separation tower, adsorbing carbon dioxide in the exhaust gas (EG4) of the melting device and discharging a low-concentration carbon dioxide-containing gas (CLG2) with a reduced carbon dioxide content by adsorption, depressurizing the separation tower, separating the carbon dioxide adsorbed on the adsorbent inside the separation tower from the adsorbent, and discharging a high-concentration carbon dioxide-containing gas (CHG2) with an increased carbon dioxide content by separation from the separation tower. From this, the first carbon dioxide separation unit (4100) can separate the high-concentration carbon dioxide-containing gas (CHG2) and the low-concentration carbon dioxide-containing gas (CLG2) from the exhaust gas (EG4) of the melting device.

[0074] The hydrogen separation unit (4200) has the role of separating the low-concentration carbon dioxide-containing gas (CLG2) supplied from the first carbon dioxide separation unit (4100) according to the hydrogen concentration, and the role of supplying the gas separated according to the hydrogen concentration to the methane-containing gas manufacturing unit (4400) and the melting device (5000). To this end, the hydrogen separation unit (4200) can be connected to the first carbon dioxide separation unit (4100), the methane-containing gas manufacturing unit (4400), and the melting device (5000).

[0075] The hydrogen separation unit (4200) may be a means for separating hydrogen from a low-concentration carbon dioxide-containing gas (CLG2) in the same or similar manner as the first carbon dioxide separation unit (4100). Accordingly, the hydrogen separation unit (4200) may have a structure identical or similar to the first carbon dioxide separation unit (4100). Additionally, the hydrogen separation unit (4200) may separate a high-concentration hydrogen-containing gas (HHG1) and a low-concentration hydrogen-containing gas (HLG1) from the low-concentration carbon dioxide-containing gas (CLG2), and may supply the high-concentration hydrogen-containing gas (HHG1) to the methane-containing gas manufacturing unit (4400) and to the melting device (5000). Meanwhile, the hydrogen separation unit (4200) may supply the low-concentration hydrogen-containing gas (HLG1) to the outside of the molten iron manufacturing facility. At this time, for example, the power generation facility of a steel mill can receive low-concentration hydrogen-containing gas (HLG1) from the hydrogen separation unit (4200) and use it for power generation.

[0076] The second carbon dioxide separation unit (4300) has the role of separating the exhaust gas (i.e., the exhaust gas (EG1) of the reduced iron manufacturing device) discharged from the reduced iron manufacturing device (1300) according to the carbon dioxide concentration, and also has the role of supplying the gas separated according to the carbon dioxide concentration to the iron carbide manufacturing unit (2100) and the methane-containing gas manufacturing unit (4400).

[0077] To this end, the second carbon dioxide separation unit (4300) may be installed to receive the exhaust gas (EG1) from the reduced iron manufacturing device. Additionally, the second carbon dioxide separation unit (4300) may be connected to the iron carbide manufacturing unit (2100) and the methane-containing gas manufacturing unit (4400).

[0078] The second carbon dioxide separation unit (4300) may be a means for separating carbon dioxide from the flue gas (EG1) of the reduced iron manufacturing device in the same or similar manner as the first carbon dioxide separation unit (4100). Accordingly, the second carbon dioxide separation unit (4300) may have the same or similar structure as the first carbon dioxide separation unit (4100). Additionally, the second carbon dioxide separation unit (4300) may separate high carbon dioxide content gas (CHG1) and low carbon dioxide content gas (CLG1) from the flue gas (EG1) of the reduced iron manufacturing device, supply the high carbon dioxide content gas (CHG1) to the methane-containing gas manufacturing unit (4400), and supply the low carbon dioxide content gas (CLG1) to the iron carbide manufacturing unit (2100).

[0079] The methane-containing gas manufacturing unit (4400) reacts the high-concentration carbon dioxide-containing gas (CHG2) and high-concentration hydrogen-containing gas (HHG1) supplied from the first carbon dioxide separation unit (4100) and the hydrogen separation unit (4200), and supplies the synthesized methane-containing gas (MG) to the iron carbide manufacturing unit (2100). At this time, the methane-containing gas manufacturing unit (4400) may additionally receive the high-concentration carbon dioxide-containing gas (CHG1) from the second carbon dioxide separation unit (4300) and may control the carbon dioxide concentration of the high-concentration carbon dioxide-containing gas (CHG2) during the synthesis reaction of the methane-containing gas (MG). Additionally, the methane-containing gas manufacturing unit (4400) may additionally receive gas from outside the molten iron manufacturing facility, such as hydrogen-containing byproduct gas from a steel mill and hydrogen gas produced outside the steel mill, if necessary, and may control the hydrogen concentration of the high-concentration hydrogen-containing gas (HHG1) during the synthesis reaction of the methane-containing gas (MG). The methane-containing gas manufacturing unit (4400) may be connected to the iron carbide manufacturing unit (2100), the first carbon dioxide separation unit (4100), the hydrogen separation unit (4200), the second carbon dioxide separation unit (4300), and the melting device (5000).

[0080] The methane-containing gas manufacturing unit (4400) may be a type of reaction vessel having an internal space (i.e., a synthesis space) that can be heated to a temperature at which a methane synthesis reaction can be performed. The methane-containing gas manufacturing unit (4400) can supply high-concentration carbon dioxide-containing gas (CHG2), high-concentration carbon dioxide-containing gas (CHG1), and high-concentration hydrogen-containing gas (HHG1) into the reaction vessel and heat the reaction vessel to a predetermined temperature at which methane can be synthesized. Accordingly, carbon dioxide (CO2) contained in the high-concentration carbon dioxide-containing gas (CHG2) and high-concentration carbon dioxide-containing gas (CHG1) and hydrogen (H2) contained in the high-concentration hydrogen-containing gas (HHG1) can react within the reaction vessel, and methane (CH4) can be synthesized by the reaction. The methane-containing gas (MG) synthesized in this way can be supplied to the iron carbide manufacturing unit (2100) and mainly used to manufacture reduced iron into iron carbide. In addition, the methane-containing gas (MG) remaining after being supplied to the iron carbide manufacturing unit (2100) can be supplied to the melting device (5000) and utilized as a hydrogen source.

[0081] The melting device (5000) melts an iron source and a lump body to produce molten iron, i.e., molten iron. The melting device (5000) may be, for example, a blast furnace. Also, the iron source may include sintered ore. Additionally, the iron source may further include at least one of fine ore, pellets, and scrap. At this time, the melting device (5000) uses coke as a reducing agent and a heat source to melt the iron source and the lump body to produce molten iron.

[0082] Meanwhile, the agglomerate plays the same or similar role as iron source. That is, the amount of iron source used can be reduced by the amount of agglomerate used. At this time, the agglomerate may be manufactured in an agglomerate manufacturing device (2000) and may be manufactured to contain iron carbide using reduced iron. Therefore, the amount of coke used can also be reduced by the amount of agglomerate used. For example, since the agglomerate is manufactured to contain iron carbide using reduced iron, the amount of coke used as a reducing agent can be reduced by the amount of iron carbide. In addition, since it is contained in the agglomerate in the form of iron carbide rather than in the form of reduced iron, the reduction rate of the agglomerate can be increased compared to being reduced by being contained in the agglomerate in the form of reduced iron, and additional reduction efficiency can be increased.

[0083] Hereinafter, a method for producing molten iron in a melting device (5000) is briefly described. Hot air, oxygen, and hydrogen-containing gas are blown into the lower part of the melting device (5000), i.e., the blast furnace, and sintered ore, coke, and lumps are introduced into the upper part of the blast furnace. Here, the hydrogen-containing gas may include exhaust gas (EG2) from a coke manufacturing device, methane-containing gas (MG), exhaust gas (EG3) from an iron carbide manufacturing unit, and high-concentration hydrogen-containing gas (HHG1). When hot air, oxygen, and hydrogen-containing gas are blown into the blast furnace, the coke is combusted by the hot air and oxygen. Meanwhile, the hydrogen (H2) contained in the hydrogen-containing gas is combusted into water vapor (H2O) by the hot air and oxygen, and the water vapor (H2O) reacts with the coke to be converted back into hydrogen (H2). Then, sintered ore and agglomerates are reduced and melted by the heat generated by the combustion of coke, carbon monoxide (CO), and hydrogen (H2) originating from hydrogen-containing gas, thereby producing molten iron, i.e., molten iron.

[0084] However, when coke is burned in this way, a large amount of carbon dioxide (CO2), an environmental pollutant, is generated. However, in the embodiment of the present invention, by using hydrogen-containing gas and agglomerated material, the amount of coke used can be reduced, and thus the amount of carbon dioxide (CO2) generated from coke can be significantly reduced.

[0086] Hereinafter, with reference to FIG. 1, a method for manufacturing molten iron using a molten iron manufacturing facility according to an embodiment of the present invention will be described in detail.

[0087] A method for manufacturing molten iron according to an embodiment of the present invention includes the steps of: preparing a raw material containing an iron source; preparing coke; manufacturing an agglomerate containing iron carbide using reduced iron; and introducing the raw material, coke, and agglomerate into a melting device (5000) and melting them.

[0088] In addition, the method for manufacturing molten iron according to an embodiment of the present invention may further include a process of preparing reduced iron prior to the process of manufacturing a lump body.

[0089] A process for preparing raw materials is performed. The process for preparing raw materials may include a process of receiving sintered ore. At this time, the sintered ore may be produced in a sintered ore manufacturing device (1100). Additionally, the process for preparing raw materials may further include a process of receiving at least one of fine ore, pellets, and scrap. That is, the raw materials may include sintered ore. Additionally, the raw materials may further include at least one of fine ore, pellets, and scrap. Meanwhile, the process for preparing raw materials may include a process of manufacturing sintered ore instead of a process of receiving sintered ore. Additionally, the process for preparing raw materials may include both a process of receiving sintered ore and a process of manufacturing sintered ore.

[0090] While the raw materials are being prepared, a process for preparing coke is carried out on the other hand. The process for preparing coke may include a process of receiving coke. At this time, the coke may be produced in a coke manufacturing device (1200). Of course, the process for preparing coke may include a process of manufacturing coke instead of a process of receiving coke. Additionally, the process for preparing coke may include both a process of receiving coke and a process of manufacturing coke.

[0091] Meanwhile, the process of preparing raw materials and the process of preparing coke may proceed sequentially in any order. In other words, the order of the process of preparing coke and the process of preparing raw materials can vary.

[0092] In addition, the raw materials and coke supplied during the process of preparing the raw materials and the process of preparing the coke can be transferred to a melting device (5000) to perform the melting process so that they can be used to produce molten iron during the melting process. Of course, the supplied raw materials and coke supplied can also be temporarily stored in their respective hoppers and then transferred to the melting device (5000).

[0093] While raw materials and coke are being prepared, a process for preparing reduced iron is carried out on the other hand, and a process for manufacturing an agglomerate containing iron carbide is carried out using the reduced iron.

[0094] At this time, the process of preparing reduced iron may include a process of preparing a hydrogen-containing gas, and a process of producing reduced iron by flowing a reduced iron raw material containing iron ore through the hydrogen-containing gas and reacting it with the hydrogen-containing gas.

[0095] In addition, the process of preparing reduced iron may include a process of separating the exhaust gas discharged during the preparation of reduced iron (hereinafter referred to as the exhaust gas (EG1) of the reduced iron manufacturing device) into high carbon dioxide content gas (CHG1) and low carbon dioxide content gas (CLG1) according to carbon dioxide (CO2) content using a pressure difference, providing the low carbon dioxide content gas (CLG1) so that it can be utilized in the process of preparing iron carbide described later during the process of manufacturing a mass, and providing the high carbon dioxide content gas (CHG1) so that it can be utilized in the process of preparing methane content gas described later during the process of manufacturing a mass.

[0096] First, a hydrogen-containing gas can be provided. Specifically, flue gas containing hydrogen that is generated during the process of producing coke (hereinafter referred to as the flue gas (EG2) of the coke manufacturing device) can be supplied. That is, in the process of producing reduced iron, the flue gas (EG2) of the coke manufacturing device can be used as a hydrogen-containing gas.

[0097] The exhaust gas (EG2) of the coke manufacturing device may be discharged from the coke manufacturing device (1100). Specifically, the exhaust gas (EG2) of the coke manufacturing device may pass through the gas supply device (3000) after being discharged from the coke manufacturing device (1100). Additionally, the exhaust gas (EG2) of the coke manufacturing device may contain hydrogen (H2), methane (CH4), carbon monoxide (CO), carbon dioxide (CO2), and nitrogen (N2). At this time, when the total volume of the exhaust gas (EG2) of the coke manufacturing device is 100 volume%, hydrogen (H2) may be contained in the proportions of 56.4 volume%, methane (CH4) in the proportion of 26.6 volume%, carbon monoxide (CO) in the proportion of 8.4 volume%, carbon dioxide (CO2) in the proportion of 3.1 volume%, and nitrogen (N2) in the proportion of 5.5 volume%. As such, the volume of hydrogen (H2) and methane (CH4) in the flue gas (EG2) of the coke manufacturing device may account for almost the entire volume. Therefore, the flue gas (EG2) of the coke manufacturing device can be used as a hydrogen-containing gas. Meanwhile, the volume ratios of hydrogen (H2), methane (CH4), carbon monoxide (CO), carbon dioxide (CO2), and nitrogen (N2) described above are merely examples to explain embodiments of the present invention and are not intended to limit the present invention. Furthermore, the flue gas (EG2) of the coke manufacturing device may be referred to, for example, as coke oven gas.

[0098] Subsequently, reduced iron can be manufactured. To this end, a reduced iron raw material containing iron ore powder can be introduced into a reduced iron manufacturing device (1300). Additionally, a hydrogen-containing gas, i.e., the flue gas (EG2) of a coke manufacturing device, can be supplied to the reduced iron manufacturing device (1300). At this time, the flue gas (EG2) of the coke manufacturing device acts as both a reducing agent and a heat source. Furthermore, in the reduced iron manufacturing device (1300), the reduced iron raw material can be flowed through the hydrogen-containing gas, i.e., the flue gas (EG2) of the coke manufacturing device, and reacted with the flue gas (EG2) of the coke manufacturing device to manufacture reduced iron from the reduced iron raw material. At this time, the reduced iron raw material can be heated by heat generated by burning a portion of the flue gas (EG2) of the coke manufacturing device. Additionally, the iron ore powder contained in the reduced iron raw material can be reduced by coming into contact with the hydrogen contained in the flue gas (EG2) of the coke manufacturing device. In this way, reduced iron can be manufactured from the reduced iron raw material. At this time, the reduction rate of the reduced iron may be 60% or more and 70% or less. Preferably, the reduction rate of the reduced iron may be 62% or more and 68% or less. Such reduced iron may also be referred to as low-reduction iron.

[0099] Meanwhile, when producing reduced iron, at least one gas among FOG (FINEX Off-Gas) and LDG (Linz-Donawitz Gas) may be supplied to the reduced iron production device (1300) along with the exhaust gas (EG2) of the coke production device.

[0100] FOG may be a flue gas containing hydrogen generated in the FINEX facility. LDG may be a flue gas containing hydrogen generated in the converter refining facility. FOG and LDG can serve as a reducing agent and a heat source, similar to the flue gas (EG2) from the coke manufacturing facility. Meanwhile, the aforementioned FINEX facility is a type of facility that manufactures molten iron based on a fluidized bed reduction furnace and a molten gasification furnace.

[0101] While producing reduced iron in this manner, the exhaust gas (EG1) of the reduced iron production device can be separated into high carbon dioxide content gas (CHG1) and low carbon dioxide content gas (CLG1) according to carbon dioxide (CO2) content by utilizing a pressure difference. That is, the exhaust gas (EG1) of the reduced iron production device is introduced into the second carbon dioxide separation unit (4300) of the gas synthesis device (4000), and the exhaust gas (EG1) of the reduced iron production device can be separated into high carbon dioxide content gas (CHG1) and low carbon dioxide content gas (CLG1) by utilizing a pressure difference while periodically changing the pressure of the second carbon dioxide separation unit (4300). Here, the term "pressure difference" refers to the pressure difference at which the gas of each component contained in the exhaust gas (EG1) of the reduced iron production device can be adsorbed by the adsorbent in the second carbon dioxide separation unit (4300).

[0102] More specifically, by applying a Pressure Swing Adsorption (PSA) method, the exhaust gas (EG1) of a reduced iron manufacturing device is supplied to a second carbon dioxide separation unit (4300) filled with an adsorbent having porous particles, such as a Carbon Molecular Sieve (CMS), to selectively adsorb gas, and the second carbon dioxide separation unit (4300) can be pressurized to a pressure at which carbon dioxide can be adsorbed. Additionally, carbon dioxide is adsorbed onto the adsorbent, and the low carbon dioxide-containing gas (CLG1), from which carbon dioxide has been separated by adsorption, can be discharged from the second carbon dioxide separation unit (4300).

[0103] Additionally, when the low carbon dioxide-containing gas (CLG1) is discharged, the second carbon dioxide separation unit (4300) can be depressurized to a pressure that can separate carbon dioxide from the adsorbent. As carbon dioxide is separated by depressurization, a high carbon dioxide-containing gas (CHG1) with a higher carbon dioxide content than the low carbon dioxide-containing gas (CLG1) is formed within the second carbon dioxide separation unit (4300), and this can be discharged from the second carbon dioxide separation unit (4300).

[0104] Of course, the exhaust gas (EG1) of the reduced iron manufacturing device can be pressurized to a pressure at which carbon dioxide can be adsorbed, and the pressurized exhaust gas (EG1) of the reduced iron manufacturing device can be passed through the adsorbent of the second carbon dioxide separation unit (4300) to adsorb carbon dioxide from the exhaust gas (EG1) of the reduced iron manufacturing device. At this time, the gas that passes through the adsorbent and is discharged from the second carbon dioxide separation unit (4300) may be a low carbon dioxide content gas (CLG1) from which carbon dioxide has been separated by adsorption. Additionally, the supply of the flue gas (EG1) of the pressurized reduced iron manufacturing device to the second carbon dioxide separation unit (4300) is stopped, and the internal pressure of the second carbon dioxide separation unit (4300), which is pressurized by the pressure of the flue gas (EG1) of the reduced iron manufacturing device, is reduced to separate carbon dioxide from the adsorbent, and the residual gas inside the second carbon dioxide separation unit (4300) containing the carbon dioxide separated from the adsorbent can be discharged from the second carbon dioxide separation unit (4300) as a high carbon dioxide content gas (CHG1).

[0105] In this way, the exhaust gas (EG1) of the reduced iron manufacturing device is supplied to the second carbon dioxide separation unit (4300) to be separated and discharged as high carbon dioxide content gas (CHG1) and low carbon dioxide content gas (CLG1).

[0106] In addition, when the high carbon dioxide-containing gas (CHG1) and the low carbon dioxide-containing gas (CLG1) are separated, the high carbon dioxide-containing gas (CHG1) can be provided to be utilized as a methane raw material in the process of preparing the methane-containing gas described later during the process of manufacturing the agglomerate. In addition, the low carbon dioxide-containing gas (CLG1) can be provided to be utilized as a reducing agent or a heat source in the process of manufacturing iron carbide described later during the process of manufacturing the agglomerate.

[0107] Once reduced iron is prepared in this way, a process for manufacturing an agglomerate is performed. At this time, the process for manufacturing the agglomerate may include a process of supplying reduced iron, a process of preparing a methane-containing gas, a process of preparing a hydrogen-containing gas, a process of producing iron carbide by reacting the reduced iron with the hydrogen-containing gas and the methane-containing gas while flowing it, and a process of molding the iron carbide into an agglomerate shape.

[0108] In addition, the process of manufacturing the agglomerate may include a process of providing exhaust gas (hereinafter referred to as exhaust gas (EG3) of the iron carbide manufacturing unit) discharged during the process of manufacturing iron carbide so that it can be utilized in at least one of the processes of preparing reduced iron and melting it.

[0109] First, reduced iron can be supplied. That is, reduced iron can be supplied from a reduced iron manufacturing device (1300). At this time, the reduced iron may be in the form of a fluid powder.

[0110] In addition, methane-containing gas can be prepared. That is, while reduced iron is supplied from the reduced iron manufacturing device (1300), methane-containing gas can be prepared using the gas synthesis device (4000) on the other hand.

[0111] To this end, the exhaust gas (hereinafter referred to as the exhaust gas of the melting device (EG4)) discharged from the melting device (5000) can be separated into a high-concentration carbon dioxide-containing gas (CHG2) and a low-concentration carbon dioxide-containing gas (CLG2) having a lower carbon dioxide content than the high-concentration carbon dioxide-containing gas (CHG2) by utilizing a pressure difference. More specifically, the exhaust gas (EG4) of the melting device can be supplied from the melting device (5000) to the first carbon dioxide separation unit (4100) of the gas synthesis device (4000), and the high-concentration carbon dioxide-containing gas (CHG2) and the low-concentration carbon dioxide-containing gas (CLG2) can be separated by utilizing a pressure difference and discharged from the first carbon dioxide separation unit (4100). In the method by which the first carbon dioxide separation unit (4100) separates the exhaust gas (EG4) of the melting device using a pressure difference, the method of the second carbon dioxide separation unit (4300) described above of the gas synthesis device (4000) may be applied in the same or similar manner. Of course, in addition to the method of the second carbon dioxide separation unit (4300), the method by which the first carbon dioxide separation unit (4100) separates the exhaust gas (EG4) of the melting device may be diverse, such as Temperature Swing Adsorption (TSA), Vacuum Swing Adsorption (VSA), membrane separation method, deep cryogenic method, etc.

[0112] In addition, the low-concentration carbon dioxide-containing gas (CLG2) can be separated into the high-concentration hydrogen-containing gas (HHG1) and the low-concentration hydrogen-containing gas (HLG1), which has a lower hydrogen (H2) content than the high-concentration hydrogen-containing gas (HHG1). That is, the low-concentration carbon dioxide-containing gas (CLG2) discharged from the first carbon dioxide separation unit (4100) can be supplied to the hydrogen separation unit (4200) of the gas synthesis device (4000). Furthermore, in the hydrogen separation unit (4200), the low-concentration carbon dioxide-containing gas (CLG2) can be separated into the high-concentration hydrogen-containing gas (HHG1) and the low-concentration hydrogen-containing gas (HLG1) by a pressure change adsorption (PSA) method using a pressure difference. At this time, the high-concentration hydrogen-containing gas (HHG1) can be used as a raw material for methane synthesis in a subsequent process.

[0113] Next, methane-containing gas (MG) can be synthesized. That is, high-concentration carbon dioxide-containing gas (CHG2) and high-concentration hydrogen-containing gas (HHG1) are supplied from the first carbon dioxide separation unit (4100) and the hydrogen separation unit (4200). At this time, high-concentration carbon dioxide-containing gas (CHG1) can be supplied from the hydrogen separation unit (4300). In addition, methane-containing gas (MG) can be synthesized by mixing and heating these gases in the methane-containing gas manufacturing unit (4400) of the gas synthesis device (4000).

[0114] More specifically, high-concentration carbon dioxide-containing gas (CHG2), high-carbon dioxide-containing gas (CHG1), and high-concentration hydrogen-containing gas (HHG1) are supplied to the methane-containing gas manufacturing unit (4400), and the methane-containing gas manufacturing unit (4400) can be heated to a predetermined temperature at which methane can be synthesized. At this time, carbon dioxide (CO2) and hydrogen (H2) can react in the methane-containing gas manufacturing unit (4400). This reaction can be, for example, reaction equation 1, and methane (CH4) can be synthesized by this reaction.

[0115] Reaction Equation 1) CO2 + 4H2 = CH4 + 2H2O (△Ho = -165 kJ / mol, exothermic reaction)

[0117] Meanwhile, when synthesizing methane (CH4) in the methane-containing gas manufacturing unit (4400), in order to control the hydrogen (H2) concentration, hydrogen-containing byproduct gas from the steel mill and hydrogen gas supplied from outside the steel mill may be additionally supplied to the methane-containing gas manufacturing unit (4400).

[0118] Additionally, before discharging the methane-containing gas (MG) from the methane-containing gas manufacturing unit (4400), water (H2O) can be removed from the methane-containing gas (MG). At this time, the method of removing water (H2O) from the methane-containing gas (MG) can be varied and is not specifically limited.

[0119] Meanwhile, the methane-containing gas (MG) discharged from the methane-containing gas manufacturing unit (4400) can be supplied to the iron carbide manufacturing unit (2100) and used as a raw material to carbonize reduced iron during iron carbide manufacturing, and can be supplied to the melting unit (5000) via the gas supply device (3000) and used as a reducing agent or heat source during molten iron manufacturing.

[0120] In this manner, while synthesizing methane-containing gas (MG), a portion of the high-concentration hydrogen-containing gas (HHG1) separated from the low-concentration carbon dioxide-containing gas (CLG2) in the hydrogen separation unit (4200) can be supplied to the melting device (5000). At this time, the high-concentration hydrogen-containing gas (HHG1) can be used as a reducing agent and a heat source in the melting device (5000). Additionally, the low-concentration hydrogen-containing gas (HLG1) can be supplied to other facilities, such as power generation facilities. The low-concentration hydrogen-containing gas (HLG1) can be used as fuel.

[0121] Additionally, hydrogen-containing gas can be prepared. That is, while methane-containing gas is prepared using a gas synthesis device (4000), low carbon dioxide-containing gas (CLG1) can be supplied from a second carbon dioxide separation unit (4300) to prepare hydrogen-containing gas, and flue gas (EG2) from a coke manufacturing device (1100) can be supplied through a gas supply device (3000). At this time, either the low carbon dioxide-containing gas (CLG1) or the flue gas (EG2) from the coke manufacturing device can be prepared as hydrogen-containing gas, or both of these gases can be prepared as hydrogen-containing gas.

[0122] In this way, methane-containing gas (MG) is synthesized and hydrogen-containing gas is prepared, from which iron carbide can be produced.

[0124] Figure 2 is a graph showing the results of predicting the reduction rate in a blast furnace for reduced iron according to a comparative example of the present invention.

[0125] Before explaining the process of manufacturing iron carbide, first, the reason for manufacturing iron carbide using reduced iron and manufacturing agglomerate with this iron carbide in the embodiment of the present invention will be explained.

[0126] First, the composition of the reducing gas inside the blast furnace was simulated when the reduced iron was manufactured as a lump (a comparative example described later) and the blast furnace was operated while blowing hydrogen-containing gas into the tuyeres of the melting device (5000), that is, the blast furnace. The reduction rate for the fine ore (iron ore), sintered ore, and the lump (reduced iron) was tested, and the reduction rate for each location inside the blast furnace from the charging port to the fusion zone was predicted and plotted as a graph in FIG. 2.

[0127] Referring to Fig. 2, it can be seen that while the reduction rate of fine ore increases as it approaches the fusion zone of the blast furnace, the reduction rate of sintered ore converges to a level lower than that of fine ore, for example, 90%. At this time, the reduction rate of reduced iron exhibits behavior similar to that of sintered ore. Accordingly, it can be confirmed that even if a portion of the sintered ore is replaced with reduced iron and fed into the blast furnace, it is difficult to increase the reduction rate within the furnace. In other words, it is difficult to improve the reduction efficiency within the melting device by manufacturing reduced iron as an agglomerate (comparative example) and charging it into the blast furnace.

[0128] Therefore, in the embodiment of the present invention, instead of manufacturing the reduced iron as is into an agglomerate, the reduced iron is treated to contain iron carbide and then manufactured into an agglomerate, and by introducing this into the blast furnace, the reduction efficiency within the blast furnace can be improved.

[0130] Referring to FIG. 1, a method for manufacturing molten iron according to an embodiment of the present invention will be described.

[0131] Subsequently, iron carbide can be produced by flowing reduced iron and reacting it with hydrogen-containing gas and methane-containing gas. To this end, reduced iron supplied in a powder form to enable flow can be introduced into the iron carbide production section (2100) of the agglomerate manufacturing device (2000). Additionally, reduced iron can be flowed within the iron carbide production section (2100). At this time, hydrogen-containing gas, such as low carbon dioxide-containing gas (CLG1) and flue gas (EG2) from a coke manufacturing device, and methane-containing gas (MG) can be supplied to the iron carbide production section (2100). Furthermore, iron carbide (Fe3C) can be produced by reacting reduced iron with hydrogen-containing gas and methane-containing gas (MG) within the iron carbide production section (2100). At this time, the iron carbide (Fe3C) may contain attached carbon. The attached carbon may be carbon attached to the surface of the iron carbide (Fe3C).

[0132] Meanwhile, attached carbon can act as a lubricant during the manufacture of agglomerate bodies. Accordingly, the more attached carbon the iron carbide contains, the more difficult it may be to manufacture the agglomerate body. Therefore, in the process of manufacturing iron carbide, the temperature of the internal space (carbonization space) of the iron carbide manufacturing unit (2100) can be controlled to suppress the generation of attached carbon while reacting reduced iron with hydrogen-containing gas and methane-containing gas (MG). Specifically, after controlling the temperature of the internal space (carbonization space) of the iron carbide manufacturing unit (2100) to 600 to 700 degrees, iron carbide (Fe3C) can be manufactured by introducing reduced iron into the temperature-controlled internal space and allowing it to flow while reacting the reduced iron with hydrogen-containing gas and methane-containing gas (MG). Accordingly, the content of attached carbon in the iron carbide can be reduced.

[0133] Meanwhile, the exhaust gas (EG3) from the iron carbide manufacturing unit generated during the process of manufacturing iron carbide can be provided for use in manufacturing reduced iron in the reduced iron manufacturing device (1300) and for use in manufacturing molten iron in the melting device (5000). That is, the exhaust gas (EG3) from the iron carbide manufacturing unit may contain methane (CH4) and hydrogen (H2) remaining after reacting with reduced iron, or methane (CH4) and hydrogen (H2) that have not reacted with reduced iron. Therefore, the exhaust gas (EG3) from the iron carbide manufacturing unit (2100) containing methane (CH4) and hydrogen (H2) can be provided to each so that it can be used as a heat source in the reduced iron manufacturing device (1300) and as a reducing agent in the melting device (5000).

[0134] Subsequently, iron carbide can be molded into a lump shape. That is, iron carbide produced in the iron carbide manufacturing unit (2100) can be supplied to the molding unit (2200) of the lump manufacturing device (2000), and the iron carbide can be molded into a lump shape by cold pressing or hot pressing in the molding unit (2200), and a lump containing iron carbide can be manufactured therefrom.

[0135] Meanwhile, in the process of molding iron carbide, carbon material byproducts may also be utilized to control the carbon content of the agglomerate containing iron carbide.

[0136] To this end, at least one of the first carbon material byproduct generated during the process of preparing coke and the second carbon material byproduct generated from the melting device (5000) may be supplied. The first carbon material byproduct may include coke dust. Additionally, the first carbon material byproduct may be discharged from the Coke Dry Quenching of the coke manufacturing device (1200) and may be transferred to and stored in the byproduct supply unit (2300) of the agglomerate manufacturing device (2000). The second carbon material byproduct may include blast furnace dust. Additionally, the second carbon material byproduct may be discharged from the melting device (5000) and may be transferred to and stored in the byproduct supply unit (2300).

[0137] Next, iron carbide produced in the iron carbide manufacturing unit (2100) is supplied to the molding unit (2200), and at least one of the first carbon material byproduct and the second carbon material byproduct stored in the byproduct supply unit (2300) is supplied to the molding unit (2200) and mixed to produce a mixture. Additionally, the mixture can be cold-pressed or hot-pressed into the shape of an agglomerate. From this, an agglomerate can be produced.

[0138] The process of introducing raw materials, coke, and lumps into a melting device (5000) and melting them is performed. That is, when raw materials are prepared through a process of preparing raw materials, coke is prepared through a process of preparing coke, and lumps are prepared through a process of manufacturing lumps, these can be introduced into the melting device (5000), for example, the upper part of a blast furnace. Then, hot air, pulverized coal, and high-temperature gas are introduced into the lower part of the blast furnace to reduce and melt the raw materials, and likewise reduce and melt the lumps, thereby producing molten iron from them.

[0139] At this time, the high-temperature gas may be a gas containing hydrogen. That is, the high-temperature gas may include, for example, flue gas from a coke manufacturing unit (EG2), a methane-containing gas (MG), flue gas from an iron carbide manufacturing unit (EG3), and a high-concentration hydrogen-containing gas (HHG1). Meanwhile, the high-temperature gas may further include by-product gas from a steel mill containing hydrogen and methane, or may further include hydrogen gas and methane gas supplied from outside the steel mill. Additionally, the raw material may include sintered ore and may further include at least one of fine ore, pellets, and scrap.

[0140] When raw materials, coke, and lumps are fed into the upper part of the blast furnace and hot air and high-temperature gas are fed into the lower part, the coke is combusted by the hot air and high-temperature gas. Then, the iron ore in the raw materials and the iron carbide in the lumps are reduced and melted by the heat and carbon monoxide generated by the combustion of the coke, thereby producing molten iron, or molten iron.

[0141] As described above, the molten iron manufacturing apparatus and the molten iron manufacturing method according to the embodiment of the present invention can increase the reduction efficiency by hydrogen in the melting apparatus (5000), i.e., the blast furnace, by using an agglomerated body manufactured to contain iron carbide using reduced iron as an iron source together with sintered ore, and thereby maximize the carbon substitution effect by hydrogen. Accordingly, the amount of carbon-based reducing agent, i.e., coke, used can be reduced, and thus the amount of carbon dioxide emitted can be reduced. In addition, by synthesizing a methane-containing gas (MG) from the flue gas (EG4) of the melting apparatus, which contains a large amount of hydrogen remaining after utilization in the blast furnace and also contains a large amount of carbon dioxide generated from coke, a carbon-based reducing agent, and using the synthesized gas for the production of iron carbide, the hydrogen required for the production of iron carbide can be obtained from the flue gas (EG4) of the melting apparatus, thereby improving the overall process efficiency in the molten iron manufacturing process and reducing the total amount of carbon dioxide.

[0143] FIG. 3 is a conceptual diagram for explaining blast furnace operation according to an embodiment of the present invention.

[0144] With reference to FIG. 3, the operation of a blast furnace according to an embodiment of the present invention is described. Sintered ore, fine ore, and pellets are charged as raw materials into a melting device (5000), that is, a blast furnace, and an agglomerated body containing iron carbide is charged. In addition, coke is charged into the blast furnace as a reducing agent and a heat source. In addition, hot air, oxygen-enriched blower, pulverized coal, and flue gas (EG2) from a coke manufacturing device are blown into the lower part of the blast furnace.

[0145] Accordingly, raw materials and lumps are reduced and melted inside the blast furnace. At this time, hydrogen, carbon monoxide, and nitrogen are generated in the bosch section inside the blast furnace, and hydrogen, carbon monoxide, carbon dioxide, and nitrogen are discharged from the top of the blast furnace. In addition, molten iron and slag may be discharged from the blast furnace.

[0146] More specifically, the calculation was expressed as the unit cost required to produce 1 ton of molten iron for a blast furnace with a daily molten iron production capacity of approximately 10,558 tons, and 150 kg / ton of agglomerated material containing iron carbide with a reduction rate of 66.5% and 5 wt% carbon was charged into the blast furnace. In addition, the flue gas (EG2) from the coke manufacturing unit was 136.5 Nm 3 It was injected into the bottom of the blast furnace at a rate of / ton. At this time, 1,442.8 kg / ton of raw material was charged. In addition, the gas volume in the bosch section inside the blast furnace was 1,298.3 Nm³ 3 It was maintained at / ton, and the bosch gas inside the blast furnace was adjusted to contain 18.0 volume% hydrogen (H2), 44.4 volume% carbon monoxide (CO), and 37.6 volume% nitrogen (N2). In addition, a method was applied to first reduce coke compared to current blast furnace operations to the minimum maintenance level of 280 kg / ton, and then adjust the pulverized coal injection ratio.

[0147] In addition, as a comparative example, a lump body manufactured to contain iron carbide is not used, and accordingly, raw materials are charged at a rate of 1652.0 kg / ton, and the blast furnace operation of the comparative example is performed with the conditions of the lump body and raw materials remaining the same as in the example. Then, the results of the blast furnace operation of the example and the comparative example are compared.

[0148] Below, the results of the blast furnace operations of the example and the comparative example are compared in terms of the amount of reducing agent used.

[0149] In the blast furnace operation of the example, when calculating the changes in expected reduction indices in the bulk zone, such as the indirect reduction ratio and the amount of carbon required for direct reduction, the amount of hot air, oxygen enrichment (oxygen enrichment rate 15.3%), coke, and pulverized coal required to satisfy the overall heat balance of the blast furnace are each 604.4 Nm³ 3 / ton, 144.8 Nm 3It was possible to calculate levels of / ton, 280 kg / ton, and 158 kg / ton.

[0150] On the other hand, in the blast furnace operation of the comparative example, the amount of hot air, oxygen enrichment (oxygen enrichment rate 6.53%), amount of coke, and amount of pulverized coal required to satisfy the overall heat balance of the blast furnace were evaluated to be 853.8 Nm3 / ton, 77 Nm3 / ton, 313.2 kg / ton, and 173.6 kg / ton, respectively. That is, compared to the example, it can be confirmed that the amount of coke used in the comparative example increased by 33.2 kg / ton from 280 kg / ton to 313.2 kg / ton, and the amount of pulverized coal used increased by 15.6 kg / ton from 158 kg / ton to 173.6 kg / ton.

[0151] In this case, coke and pulverized coal act as reducing agents, and an increase in the amount of coke and pulverized coal used implies that more reducing agent is used in blast furnace operation. Accordingly, it can be confirmed that the example uses less reducing agent compared to the comparative example.

[0153] Next, the results of the blast furnace operations of the exemplary and comparative examples are compared in terms of reduction rate.

[0154] In the blast furnace operation of the example, it was calculated that the indirect reduction rate of iron ore in the massive zone was 83.1% and the direct reduction rate was 16.9% (at this time, the amount of carbon required for direct reduction was 46.3 kg / ton).

[0155] On the other hand, in the blast furnace operation of the comparative example, it was calculated that the indirect reduction rate of iron ore in the massive zone was approximately 73.4% and the direct reduction rate was 26.6% (at this time, the amount of carbon required for direct reduction was 79.3 kg / ton).

[0156] In other words, it can be confirmed that the indirect reduction rate in the blast furnace operation of the example is increased compared to the comparative example. Here, the increase in the indirect reduction rate of the blast furnace operation of the example to 83.1% means that the reduction of iron ore by hydrogen is increased, and through this, it shows that the amount of carbon required for direct reduction can be reduced in the example compared to the comparative example.

[0157] Meanwhile, in the blast furnace operation of the embodiment, the internal gas after the lump phase is discharged to the outside through the top of the blast furnace in the form of flue gas, the hydrogen (H2) content is 12.6%, and the calorific value is 1076.9 kcal / Nm 3 It was possible to produce this.

[0158] On the other hand, in the blast furnace operation of the comparative example, it can be confirmed that the hydrogen (H2) content of the flue gas discharged to the outside through the top of the blast furnace is 3.2% and the calorific value is 793.3 kcal / Nm3.

[0159] Accordingly, it can be confirmed that the hydrogen emission and calorific value are increased in the embodiment compared to the comparative example. Through this, it can also be confirmed that the embodiment allows for the reuse of hydrogen and carbon dioxide separated from the flue gas compared to the comparative example.

[0161] Figure 4 is a graph showing the carbon content according to the manufacturing temperature of a mass produced according to an embodiment of the present invention.

[0162] Referring to Figure 4, when iron carbide is produced by reacting reduced iron with hydrogen-containing gas and methane-containing gas, the results of measuring the total amount of carbon generated and the change in carbon content in the form of iron carbide (Fe3C) can be seen.

[0163] Here, the bar graph represents the total carbon content of the reaction product (product) after reacting reduced iron with the above gases, and the dots represent the content of iron carbide (Fe3C) alone. Accordingly, the interval between the bar graph and the dots represents the content of carbon included in the reaction product in the form of attached carbon, which is not produced as iron carbide.

[0164] If the reaction temperature for the formation of iron carbide is too low, for example, at a reaction temperature of 550°C, the total carbon content of the product after the reaction is low. In other words, the product does not contain sufficient carbon. Furthermore, as the reaction temperature increases, it can be observed that the total carbon content and the iron carbide (Fe3C) content of the product increase. However, if the reaction temperature becomes too high, for example, at a reaction temperature of 750°C, it can be seen that while the carbon content of the product is high, the increase in the iron carbide (Fe3C) content is low. In other words, the iron carbide (Fe3C) content does not increase significantly. Accordingly, at a reaction temperature of 750°C, it can be seen that carbon is included in the product in the form of attached carbon.

[0165] In other words, when iron carbide is produced, it can be confirmed that the carbon content in the product increases as the reaction temperature increases, but instead of all the carbon becoming iron carbide, it may increase in the form of attached carbon. At this time, if a large amount of carbon attached to the surface of the iron carbide is generated, it may be difficult to produce the agglomerate. Therefore, in the embodiments of the present invention, the reaction is carried out in a temperature range in which the amount of attached carbon can be suppressed while producing iron carbide. For example, by setting the reaction temperature to a range of 600 to 700 degrees, the amount of carbon attached to the surface can be minimized while increasing the iron carbide content.

[0167] The above embodiments of the present invention are for the purpose of illustrating the present invention and are not intended to limit the present invention. It should be noted that the configurations and methods disclosed in the above embodiments of the present invention may be combined or intersected in various forms and modified, and that such modifications may also be considered within the scope of the present invention. That is, the present invention will be implemented in various different forms within the scope of the claims and equivalent technical concepts, and those skilled in the art to which the present invention pertains will understand that various embodiments are possible within the scope of the technical concept of the present invention. Explanation of the symbols

[0168] 1100: Sintered ore manufacturing device 1200: Coke manufacturing device 1300: Reduced iron manufacturing device 2000: Aggregate manufacturing device 2100: Iron Carbide Manufacturing Department 2200: Molding Department 2300: By-product supply unit 3000: Gas supply device 3100: Branching section 3200: Compression section 3300: Buffer section 4000: Gas synthesis unit 4100: 1st Carbon Dioxide Separation Unit 4200: Hydrogen Separation Unit 4300: 2nd Carbon Dioxide Separation Unit 4400: Methane-Containing Gas Production Unit 5000: Melting device

Claims

Claim 1 A molten iron manufacturing facility for producing molten iron using raw materials containing iron and coke, comprising: an agglomerate manufacturing device capable of producing an agglomerate containing iron carbide using reduced iron; and a melting device installed to receive the raw materials, coke, and agglomerate so as to melt the raw materials and the agglomerate to produce molten iron; wherein the agglomerate manufacturing device comprises: an iron carbide manufacturing section connected to one or more fluidized reduction furnaces to receive reduced iron produced in one or more fluidized reduction furnaces in a powdered state and fluidize it to produce iron carbide; and a molding section connected to the iron carbide manufacturing section to receive iron carbide produced in the iron carbide manufacturing section in a powdered state and mold it into an agglomerate. Claim 2 A molten iron manufacturing facility according to claim 1, comprising a gas synthesis device connected to the melting device to allow exhaust gas discharged from the melting device to flow in, and connected to the agglomerate manufacturing device to deliver methane-containing gas produced from the exhaust gas. Claim 3 A molten iron manufacturing facility comprising: a gas supply device that can be connected to the coke manufacturing device, the agglomerate manufacturing device, and the melting device, so as to be able to supply hydrogen-containing exhaust gas discharged from the coke manufacturing device for manufacturing coke to the agglomerate manufacturing device and the melting device in separate portions according to claim 2. Claim 4 In claim 3, the agglomerate manufacturing device is a molten iron manufacturing facility that can be connected to at least one of the coke manufacturing device and the melting device so as to receive at least one of the first carbon material byproduct discharged from the coke manufacturing device and the second carbon material byproduct discharged from the melting device. Claim 5 In claim 2, the iron carbide manufacturing unit is installed to receive reduced iron in a powdered state and is connected to the gas synthesis device, and can produce iron carbide by reacting the reduced iron with a hydrogen-containing gas and a methane-containing gas, and the molding unit is installed to receive the iron carbide in a powdered state, mold the iron carbide into the agglomerate, and supply the agglomerate to the melting device. Claim 6 The reduced iron manufacturing apparatus of claim 3, which is installed to receive a reduced iron raw material containing iron ore and can be connected to the coke manufacturing apparatus and can reduce the reduced iron raw material with a hydrogen-containing gas to produce the reduced iron; and the molten iron manufacturing apparatus is installed to receive the reduced iron from the reduced iron manufacturing apparatus. Claim 7 The molten iron manufacturing facility according to claim 5, wherein the agglomerate manufacturing device can receive and store at least one of a first carbon material byproduct discharged from a coke manufacturing device for manufacturing coke and a second carbon material byproduct discharged from a melting device, and further comprises a byproduct supply unit connected to the molding unit. Claim 8 In claim 5, the gas synthesis apparatus comprises: a first carbon dioxide separation unit that separates exhaust gas discharged from the melting device according to carbon dioxide content; a hydrogen separation unit that separates gas supplied from the first carbon dioxide separation unit according to hydrogen concentration; and a methane-containing gas production unit that reacts the gas supplied from the first carbon dioxide separation unit and the hydrogen separation unit and supplies the synthesized gas to the iron carbide production unit; a molten iron manufacturing facility. Claim 9 A molten iron manufacturing facility according to claim 8, wherein the gas synthesis device comprises a second carbon dioxide separation unit installed to receive exhaust gas discharged from a reduced iron manufacturing device for manufacturing reduced iron, and to separate the exhaust gas according to carbon dioxide concentration and supply it separately to the iron carbide manufacturing unit and the gas synthesis device. Claim 10 A method for manufacturing molten iron comprising: a process of preparing raw materials containing iron; a process of preparing coke; a process of manufacturing an agglomerate containing iron carbide using reduced iron; and a process of introducing the raw materials, the coke, and the agglomerate into a melting device and melting them, wherein the process of manufacturing the agglomerate comprises supplying reduced iron in a powdered state, flowing it to produce iron carbide, and then molding the powdered iron carbide into an agglomerate. Claim 11 A method for manufacturing molten iron according to claim 10, further comprising the process of preparing the reduced iron; and the process of manufacturing the agglomerate comprises the process of receiving the reduced iron; the process of preparing a methane-containing gas; the process of preparing a hydrogen-containing gas; the process of producing the iron carbide by flowing the reduced iron and reacting it with the hydrogen-containing gas and the methane-containing gas; and the process of molding the iron carbide to form an agglomerate shape. Claim 12 A method for producing molten iron according to claim 11, wherein the hydrogen-containing gas used when producing the iron carbide is at least one of a gas from which carbon dioxide has been removed from a hydrogen-containing flue gas generated during the production of reduced iron and a hydrogen-containing flue gas generated during the production of coke. Claim 13 A method for producing molten iron according to claim 11, wherein the process of preparing the reduced iron comprises: a process of preparing a hydrogen-containing gas; and a process of producing the reduced iron by flowing a reduced iron raw material containing iron ore through the hydrogen-containing gas and reacting it with the hydrogen-containing gas. Claim 14 A method for manufacturing molten iron according to claim 13, wherein the process of providing the hydrogen-containing gas comprises the process of receiving exhaust gas containing hydrogen that is generated during the process of providing the coke. Claim 15 A method for producing molten iron according to claim 11, wherein the process of preparing the methane-containing gas comprises: a process of separating the exhaust gas discharged from the melting device into a high-concentration carbon dioxide-containing gas and a low-concentration carbon dioxide-containing gas having a lower carbon dioxide content than the high-concentration carbon dioxide-containing gas by using a pressure difference; a process of separating the low-concentration carbon dioxide-containing gas into a high-concentration hydrogen-containing gas and a low-concentration hydrogen-containing gas having a lower hydrogen content than the high-concentration hydrogen-containing gas by using a pressure difference; and a process of synthesizing the methane-containing gas by mixing and heating the high-concentration hydrogen-containing gas and the high-concentration carbon dioxide-containing gas. Claim 16 A method for producing molten iron according to claim 15, comprising the process of providing the high-concentration hydrogen-containing gas generated during the process of providing the methane-containing gas to the melting device. Claim 17 A method for manufacturing molten iron according to claim 11, wherein the process of manufacturing the agglomerate comprises: a process of providing exhaust gas discharged during the process of manufacturing the iron carbide so that it can be utilized in at least one of the process of preparing the reduced iron and the process of melting; and the process of preparing the reduced iron comprises: a process of separating the exhaust gas discharged during the preparation of the reduced iron into a high carbon dioxide content gas and a low carbon dioxide content gas according to carbon dioxide content using a pressure difference; and a process of providing the low carbon dioxide content gas so that it can be utilized in the process of manufacturing the iron carbide, and providing the high carbon dioxide content gas so that it can be utilized in the process of preparing the methane content gas. Claim 18 A method for producing molten iron according to claim 11, wherein the process of forming the iron carbide comprises: a process of receiving at least one of a first carbon material byproduct generated in the process of preparing the coke and a second carbon material byproduct generated from the melting device; a process of mixing the iron carbide with at least one of the first carbon material byproduct and the second carbon material byproduct to produce a mixture; and a process of pressing the mixture.

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