Molten iron manufacturing equipment and molten iron manufacturing method

Abstract

The present invention relates to molten iron manufacturing equipment and a molten iron manufacturing method and, more specifically, to molten iron manufacturing equipment and a molten iron manufacturing method which are for manufacturing molten iron by producing reduced iron fines and melting the produced reduced iron fines. The molten iron manufacturing equipment according to an embodiment of the present invention comprises: a reduction unit capable of reducing a powder raw material so as to produce reduced iron fines; a melting unit capable of melting the reduced iron fines; a first auxiliary raw material supply unit capable of supplying an auxiliary raw material to the reduction unit; a cohesion evaluation unit capable of receiving at least a portion of the reduced iron fines from the reduction unit and evaluating the cohesion; and a control unit, which receives information about the cohesion from the cohesion evaluation unit so that the amount of the auxiliary raw material supplied by the first auxiliary raw material supply unit can be adjusted.

Description

Molten iron manufacturing equipment and molten iron manufacturing method

[0001] The present invention relates to a molten iron manufacturing facility and a molten iron manufacturing method, and more specifically, to a molten iron manufacturing facility and a molten iron manufacturing method for manufacturing powdered reduced iron and melting the manufactured powdered reduced iron to produce molten iron.

[0002] Recently, hydrogen reduction ironmaking process technology, which uses hydrogen gas instead of fossil fuels such as coal to produce molten iron, is being researched and developed. While fossil fuels like coal generate carbon dioxide when reacting with iron ore, hydrogen gas reacts with iron ore to produce water or steam; therefore, the hydrogen reduction ironmaking process can drastically reduce carbon emissions during molten iron production.

[0003] In such a hydrogen reduction ironmaking process, powdered iron ore is reacted with high-temperature hydrogen gas to produce finely reduced iron, which is then transported at high temperatures to an electric furnace and melted to produce molten iron. This process is carried out continuously. However, the high-temperature finely reduced iron produced by reducing iron ore with hydrogen gas has high agglomeration, which poses a problem as it adversely affects the continuous process. Therefore, there is a need to devise measures to minimize the agglomeration of finely reduced iron.

[0004] (Prior Art Literature)

[0005] Korean Patent Publication No. 10-2024-0069152

[0006] The present invention provides a molten iron manufacturing facility and a molten iron manufacturing method that can improve operational efficiency by minimizing the aggregation of reduced iron powder.

[0007] A molten iron manufacturing facility according to an embodiment of the present invention comprises: a reduction unit capable of producing powdered reduced iron by reducing a powdered raw material; a melting unit capable of melting the powdered reduced iron; a first auxiliary raw material supply unit installed to supply auxiliary raw materials to the reduction unit; an agglomeration degree evaluation unit capable of evaluating the agglomeration degree by receiving at least a portion of the powdered reduced iron from the reduction unit; and a control unit capable of adjusting the amount of auxiliary raw materials supplied by the first auxiliary raw material supply unit by receiving information regarding the agglomeration degree from the agglomeration degree evaluation unit.

[0008] If the degree of cohesion is higher than the set value, the control unit can increase the amount of auxiliary material supplied by the first auxiliary material supply unit compared to before the degree of cohesion is evaluated.

[0009] It further includes a second auxiliary material supply unit installed to supply auxiliary materials to the melting unit; and the control unit can adjust the amount of auxiliary materials supplied by the second auxiliary material supply unit so that the total amount of auxiliary materials supplied by the first auxiliary material supply unit and the second auxiliary material supply unit is maintained within a set range.

[0010] The above-mentioned aggregation degree evaluation unit may include: a reactor having a receiving space capable of receiving at least a portion of the reduced iron produced in the reduction unit and capable of pressurizing the reduced iron received in the receiving space; a separator capable of receiving the reduced iron pressurized in the reactor and separating aggregated reduced iron with a particle size greater than or equal to a set particle size; and a calculator capable of measuring the mass of the aggregated reduced iron and calculating the aggregation degree according to the following mathematical formula.

[0011] [Mathematical Formula]

[0012]

[0013] The apparatus further includes a storage unit capable of receiving and storing the reduced iron produced in the reduction unit, and supplying the reduced iron stored in the storage unit to the melting unit; and the reactor can pressurize the reduced iron by simulating the pressure applied to the reduced iron stored in the lower part of the storage unit.

[0014] The above storage unit may be installed to be movable between the reduction unit and the dissolution unit.

[0015] The above reduction unit includes a plurality of reduction furnaces installed to sequentially reduce powder raw materials while moving them; and the above melting unit may include an electric furnace having a melting space capable of melting the powdered reduced iron produced in the reduction unit.

[0016]

[0017] In addition, a method for manufacturing molten iron according to an embodiment of the present invention comprises: a process of supplying a powder raw material to a reduction section; a process of reducing the powder raw material in the reduction section to produce powdered reduced iron; a process of evaluating the degree of agglomeration of the produced powdered reduced iron; a process of receiving information regarding the evaluated degree of agglomeration and adjusting the amount of auxiliary raw material to be supplied to the reduction section; and a process of supplying the powdered raw material and the adjusted amount of auxiliary raw material to the reduction section, moving the produced powdered reduced iron to a melting section, and melting it.

[0018] The above powder raw material may include iron ore having a particle size greater than 0 mm and less than or equal to 8 mm.

[0019] The process of manufacturing the above-mentioned reduced iron may include a process of reducing the powder raw material by supplying hydrogen gas to the reduction unit.

[0020] The process of evaluating the degree of aggregation described above may include: a process of pressurizing the manufactured reduced iron; a process of separating aggregated reduced iron with a particle size greater than or equal to a set particle size from the pressurized reduced iron; and a process of measuring the mass of the aggregated reduced iron and calculating the degree of aggregation according to the following mathematical formula.

[0021] [Mathematical Formula]

[0022]

[0023] The above-mentioned melting process includes: a process of storing powdered reduced iron produced by supplying powdered raw materials and a controlled amount of auxiliary raw materials to the reduction section; and a process of supplying the stored powdered reduced iron to the melting section; and the process of pressurizing the powdered reduced iron can pressurize the powdered reduced iron by simulating the maximum pressure applied to the powdered reduced iron during the process of storing the powdered reduced iron.

[0024] In the process of adjusting the amount of auxiliary material to be supplied to the reduction section, if the evaluated cohesiveness is higher than the set value, the amount of auxiliary material to be supplied to the reduction section can be increased compared to before the cohesiveness was evaluated.

[0025] The above dissolving process includes a process of supplying auxiliary materials to the dissolving section; and the process of supplying auxiliary materials to the dissolving section may supply auxiliary materials to the dissolving section such that the total amount of auxiliary materials supplied to the reducing section and the dissolving section is maintained within a set range.

[0026] The above auxiliary raw material may include at least one of powdered limestone and powdered dolomite.

[0027] According to an embodiment of the present invention, the degree of aggregation of the manufactured reduced iron powder is evaluated, and the amount of auxiliary raw material supplied during the production of the reduced iron powder can be adjusted by immediately reflecting the evaluated result.

[0028] Accordingly, the aggregation of reduced iron particles during storage can be minimized, and by melting them in the melting section under optimal conditions while ensuring smooth slag flowability, the manufacturing efficiency and quality of molten iron can be improved.

[0029] FIG. 1 is a schematic diagram showing a molten iron manufacturing facility according to an embodiment of the present invention.

[0030] FIG. 2 is a diagram showing the detailed configuration of a cohesiveness evaluation unit according to an embodiment of the present invention.

[0031] FIG. 3 is a diagram schematically illustrating a method for manufacturing molten iron according to an embodiment of the present invention.

[0032] 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 but may be implemented in various different forms, and 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 explain the invention in detail, the drawings may be exaggerated, and like reference numerals in the drawings refer to like elements.

[0033]

[0034] FIG. 1 is a schematic diagram showing a molten iron manufacturing facility according to an embodiment of the present invention, and FIG. 2 is a diagram showing the detailed configuration of a cohesiveness evaluation unit according to an embodiment of the present invention.

[0035] Referring to FIGS. 1 and 2, a molten iron manufacturing facility according to an embodiment of the present invention comprises a reduction unit (400) capable of reducing powder raw materials to produce powdered reduced iron, a melting unit (600) capable of melting the powdered reduced iron, a first auxiliary raw material supply unit (200) installed to supply auxiliary raw materials to the reduction unit (400), an agglomeration degree evaluation unit (900) capable of receiving at least a portion of the powdered reduced iron from the reduction unit (400) and evaluating the agglomeration degree, and a control unit (1000) capable of receiving information regarding the agglomeration degree from the agglomeration degree evaluation unit (900) and adjusting the amount of auxiliary raw materials supplied by the first auxiliary raw material supply unit (200). In addition, the molten iron manufacturing facility according to an embodiment of the present invention may further include a powder raw material supply unit (100) installed to supply powder raw material to a reduction unit (400) and a reduction gas supply unit (300) installed to supply reduction gas to a reduction unit (400).

[0036] The powder raw material supply unit (100) is installed to supply powder raw materials to the reduction unit (400). Here, the powder raw materials may include, for example, iron ore in powder form having a particle size greater than 0 mm and less than or equal to 8 mm, i.e., powdered iron ore. The powder raw material supply unit (100) may include a storage unit (not shown) having a storage space for storing powder raw materials. Powder raw materials may be stored for a long time in the storage space of the storage unit, or temporarily stored before supplying powder raw materials to the reduction unit (400). Such a storage unit may include, for example, a hopper, and may preheat the raw materials within the storage unit by receiving high-temperature gas.

[0037] The first auxiliary material supply unit (200) is installed to supply auxiliary materials to the reduction unit (400). The auxiliary materials may include at least one of limestone (CaCO3) and dolomite (CaCO3·MgCO3). When such auxiliary materials are delivered to the melting unit (600), for example, an electric furnace, they can improve the flowability of the slag generated when melting the pulverized reduced iron. Additionally, when such auxiliary materials are supplied to the reduction unit (400), they adhere to the surface of the pulverized iron ore or pulverized reduced iron within the reduction unit (400) and serve to prevent aggregation. Here, the auxiliary materials may be stored in the first auxiliary material supply unit (200) in powder form and supplied to the reduction unit (400) together with the powder raw materials.

[0038] The reducing gas supply unit (300) is installed to store reducing gas and supply reducing gas to the reducing unit (400). Here, the reducing gas may include hydrogen gas, and the hydrogen gas may be included in a ratio of 80 to 100% of the total reducing gas. The hydrogen gas stored in the reducing gas supply unit (300) may be produced by electrolyzing water, but is not limited thereto, and may be produced by various methods such as decomposing ammonia gas or producing hydrogen gas by chemically reacting natural gas. For example, ammonia gas may be decomposed into hydrogen gas and nitrogen gas at high temperatures, and the hydrogen gas after decomposition may be used as reducing gas, and the nitrogen gas may be used as purge gas supplied to the reducing unit (400).

[0039] The reducing gas supply unit (300) can supply reducing gas to the reducing unit (400) through a reducing gas supply line that interconnects the reducing gas supply unit (300) and the reducing unit (400). At this time, the amount of reducing gas supplied by the reducing gas supply unit (300) to the reducing unit (400) may be more than twice the amount required to reduce all the powder raw materials supplied to the reducing unit (400). In order to improve the reaction efficiency between the powder raw materials and the reducing gas, the amount of reducing gas may be controlled to a range of, for example, more than twice and less than three times the amount required to reduce all the powder raw materials supplied to the reducing unit (400).

[0040] A heater (350) for heating the reducing gas supplied from the reducing gas supply unit (300) to the reducing unit (400) may be installed in the reducing gas supply line. In the reducing unit (400), a powder raw material containing iron ore and a reducing gas containing hydrogen gas react to reduce the iron ore. Since such a reaction between iron ore and hydrogen gas is a strong endothermic reaction, the reaction efficiency can be improved if the hydrogen gas supplied to the reducing unit (400) is heated to a temperature of 800°C or higher, more suitably 850°C or higher. Accordingly, the heater (350) is installed in the reducing gas supply line and can heat the low-temperature hydrogen gas supplied from the reducing gas supply unit (300) to a temperature of 800 to 1200°C and supply it to the reducing unit (400). Since the heater (350) may be equipped with various structures for heating the reducing gas in a direct or indirect heating manner, a detailed description thereof will be omitted.

[0041] The reduction unit (400) can reduce powder raw materials to produce powdered reduced iron, for example, Direct Reduced Iron (DRI). That is, the reduction unit (400) receives powdered iron ore, which is a powder raw material, from the powder raw material supply unit (100) and receives reducing gas from the reducing gas supply unit (300), and can produce powdered reduced iron by reacting the powdered iron ore with the reducing gas. Such a reduction unit (400) may include a reduction furnace having a reduction space capable of producing powdered reduced iron using the reducing gas. Such a reduction furnace may include a fluidized reduction furnace (410, 420, 430, 440) that produces reduced iron powder while flowing powder raw materials, and the fluidized reduction furnace (410, 420, 430, 440) may be provided as a single unit, but as shown in FIG. 1, a plurality of fluidized reduction furnaces (410, 420, 430, 440) may be connected to effectively reduce low-grade iron ore with low iron content, thereby producing reduced iron powder while sequentially moving powder raw materials. At this time, there is no limit to the number of fluid reduction furnaces (410, 420, 430, 440), but in order to sufficiently reduce the powder raw material, the reduction unit (400) may be composed of four reduction furnaces including a first fluid reduction furnace (410), a second fluid reduction furnace (420), a third fluid reduction furnace (430), and a fourth fluid reduction furnace (440), as shown in FIG. 1. At this time, the powder raw material supply unit (100) and the first auxiliary raw material supply unit (200) supply powder raw material and auxiliary raw material to the first fluid reduction furnace (410), and the reduction gas supply unit (300) may supply reduction gas to the fourth fluid reduction furnace (440). The powder raw material supplied to the first fluidized reduction furnace (410) can be produced as reduced iron powder by sequentially moving through the second fluidized reduction furnace (420), the third fluidized reduction furnace (430), and the fourth fluidized reduction furnace (440) and being reduced. The reduced iron powder produced in this way can have a reduction rate of 85 to 100%, i.e., a metallization rate.

[0042] The reduced iron powder produced in the reduction section (400) is generally supplied to the melting section (600). As shown in FIG. 1, the reduced iron powder produced by passing through the first fluidized reduction furnace (410), the second fluidized reduction furnace (420), the third fluidized reduction furnace (430), and the fourth fluidized reduction furnace (440) is discharged from the fourth fluidized reduction furnace (440) and supplied to the melting section (600). Here, as described above, powder raw materials and a reducing gas of 800°C or higher are supplied to the reduction space to produce reduced iron powder. Accordingly, the reduced iron powder produced in the reduction section (400) is discharged at a high temperature of, for example, 600 to 800°C, even considering heat loss. The reduced iron powder discharged at such a high temperature can be supplied to the melting section (600) via the storage section (700).

[0043] The storage unit (700) has a storage space capable of receiving and storing the reduced iron produced in the reduction unit (400), and is installed to supply the reduced iron stored in the storage space to the melting unit (600). For example, high-temperature reduced iron produced by reducing iron ore having a particle size greater than 0 mm and less than or equal to 8 mm is stored in the storage unit (700) for a long time or temporarily, and then transferred to the melting unit (600). Such a storage unit (700) may include, for example, a hopper, and such a hopper may be installed to be movable between the reduction unit (400) and the melting unit (600) in order to receive and store the reduced iron from the reduction unit (400) and supply the stored reduced iron to the melting unit (600).

[0044] Meanwhile, in the reduction section (400), a large amount of byproduct is discharged in addition to the reduced iron. The byproduct discharged from the reduction section (400) may include steam. As described above, in the reduction section (400), reduced iron is produced by the reaction of iron ore and hydrogen gas. At this time, the oxygen component of the iron ore reacts with the hydrogen component of the hydrogen gas, generating a large amount of steam within the reduction space, and the generated steam is discharged from the reduction section (400) as byproduct. Additionally, the byproduct discharged from the reduction section (400) may further include hydrogen gas and nitrogen gas. As described above, since the reducing gas is supplied in a range of more than 2 times and less than 3 times the amount required to reduce all the raw materials supplied to the reduction section (400), the remaining hydrogen gas that does not react with the raw materials is discharged from the reduction section (400) as byproduct. Additionally, a purge gas, such as nitrogen gas, may be supplied to the reduction section (400), and the nitrogen gas supplied for purging may be discharged as a byproduct from the reduction section (400). Such byproducts move along the flow of the reduction gas within the reduction section (400) and are discharged from the first fluidized reduction furnace (410), and the discharged byproducts may be supplied to the extraction section (500).

[0045] The extraction unit (500) extracts hydrogen gas from by-products discharged from the reduction unit (400). As previously described, the by-products discharged from the reduction unit (400) include water vapor, hydrogen gas, and nitrogen gas. The extraction unit (500) is connected to the reduction unit (400) and can extract hydrogen gas from the by-products supplied from the reduction unit (400). This extraction unit (500) can extract hydrogen gas from the by-products using a pressure swing absorption (PSA) method. The pressure swing absorption method extracts gas by utilizing the adsorption selectivity of each component for an adsorbent. For example, the extraction unit (500) can use a carbon molecular sieve capable of adsorbing hydrogen components as an adsorbent to extract hydrogen gas from by-products containing various gases in addition to hydrogen gas. At this time, the hydrogen component adsorbed on the adsorbent can be desorbed and extracted as hydrogen gas, and the extraction unit (500) can extract hydrogen gas from the byproduct by repeatedly performing the adsorption and desorption of the hydrogen component in this way.

[0046] The hydrogen gas extracted from the extraction unit (500) can be used for various purposes. For example, the reduction unit (400) can use the extracted hydrogen gas to reduce powder raw materials, namely iron ore. Since hydrogen gas is a very expensive gas, and is used in large quantities—more than twice the amount required to reduce all the raw materials supplied to the reduction unit (400)—the hydrogen gas extracted from the extraction unit (500) can be reused as a reducing gas to reduce iron ore in order to reduce costs through resource recycling. To this end, the extraction unit (500) is connected to a reducing gas supply line and can supply hydrogen gas to the reducing gas supply line, and the hydrogen gas supplied from the extraction unit (500) can be delivered to the reduction unit (400) and used for the reduction of iron ore.

[0047] The melting unit (600) receives reduced iron powder and can melt the received reduced iron powder using electric heat. For example, the melting unit (600) can receive reduced iron powder from the storage unit (700) and melt it by heating it with electrical energy. Such a melting unit (600) may include an electric furnace having a melting space capable of melting reduced iron powder using electric heat. Such an electric furnace may include an electric furnace body (610) having a melting space and an electrode rod (620) in which at least a portion is placed in the melting space to generate electric heat. When reduced iron powder is loaded into the melting space, the electric furnace applies power to the electrode rod (620) to melt the reduced iron powder.

[0048] Meanwhile, the molten iron manufacturing facility according to an embodiment of the present invention may further include a second auxiliary material supply unit (800) installed to supply auxiliary materials to a melting unit (600). The second auxiliary material supply unit (800) is installed to supply auxiliary materials to the melting unit (600). For example, the second auxiliary material supply unit (800) may be installed to supply auxiliary materials to a storage unit (700), and in this case, the auxiliary materials supplied from the second auxiliary material supply unit (800) may be supplied to the melting unit (600) via the storage unit (700). The second auxiliary raw material supply unit (800) can supply an auxiliary raw material comprising at least one of limestone (CaCO3) and dolomite (CaCO3·MgCO3) to the melting unit (600), and the auxiliary raw material can be stored in the second auxiliary raw material supply unit (800) in powder form and supplied to the melting unit (600).

[0049] In this way, the reduced iron produced in the reduction section (400) is stored in the storage section (700) and then supplied to the melting section (600) to be produced as molten iron. However, the reduced iron produced in the reduction section (400) by reacting with high-temperature hydrogen gas has a high reduction rate and is stored in the storage section (700) in a high-temperature state, resulting in high cohesiveness. Accordingly, the reduced iron stored in the storage section (700) for a long time or temporarily may undergo cohesion due to its own weight while remaining in the storage section (700). If cohesion occurs, it may cause adverse effects on the operation, such as blocking the inlet for supplying the reduced iron to the melting section (600).

[0050] Meanwhile, as previously mentioned, auxiliary materials such as limestone (CaCO3) and dolomite (CaCO3·MgCO3) serve to prevent aggregation when supplied to the reduction section (400) by adhering to the surface of the iron ore or iron ore within the reduction section (400). Accordingly, it is possible to consider supplying an excessive amount of auxiliary materials such as limestone (CaCO3) and dolomite (CaCO3·MgCO3) to the reduction section (400) to minimize the aggregation of iron ore within the storage section (700). However, since the reduction section (400) manufactures iron ore by flowing iron ore, if an excessive amount of auxiliary materials is supplied to the reduction section (400) in addition to iron ore, there is a problem that the overall fluidity may decrease and the reduction efficiency may also decrease.

[0051] Accordingly, the molten iron manufacturing facility according to an embodiment of the present invention includes an aggregation degree evaluation unit (900) capable of evaluating the aggregation degree by receiving at least a portion of the reduced iron from a reduction unit (400), and a control unit (1000) capable of receiving information regarding the aggregation degree from the aggregation degree evaluation unit (900) and adjusting the amount of auxiliary raw material supplied by the first auxiliary raw material supply unit (200) to an optimal condition, thereby minimizing the aggregation of the reduced iron and improving the operational efficiency. Below, the detailed configuration and operation of the aggregation degree evaluation unit (900) and the control unit (1000) will be described in more detail.

[0052] The cohesion evaluation unit (900) may evaluate the cohesion degree by receiving at least a portion of the reduced iron from the reduction unit (400). For example, the cohesion evaluation unit (900) evaluates the cohesion degree by receiving a portion of the reduced iron produced from the reduction unit (400), and separately, the remainder of the reduced iron produced from the reduction unit (400), i.e., the remaining reduced iron, may be stored in the storage unit (700), supplied to the dissolution unit (600), and then dissolved. Additionally, the cohesion evaluation unit (900) may evaluate the cohesion degree by receiving the entire amount of the reduced iron produced from the reduction unit (400), in which case the supply of reduced iron to the storage unit (700) may be temporarily suspended. In addition, the cohesion evaluation unit (900) may evaluate the cohesion by receiving at least a portion of the reduced iron once while the reduced iron is being manufactured and melted to produce molten iron, or by receiving at least a portion of the reduced iron at set intervals.

[0053] As shown in FIG. 2, the aggregation evaluation unit (900) may include a receiving space capable of receiving at least a portion of the reduced iron produced in the reduction unit (400), a reactor (910) capable of pressurizing the reduced iron received in the receiving space, a separator (920) capable of receiving the reduced iron pressurized in the reactor (910) and separating the aggregated reduced iron with a set particle size or larger, and a calculator (930) capable of measuring the mass of the aggregated reduced iron to calculate the aggregation degree.

[0054] The reactor (910) has a receiving space capable of receiving at least a portion of the reduced iron produced in the reduction section (400). Such a reactor (910) may include various containers that provide a receiving space capable of receiving the reduced iron.

[0055] Additionally, a pressurizing member capable of pressurizing the reduced iron contained in the receiving space may be installed in the reactor (910). Such a pressurizing member can pressurize the contained reduced iron, for example, by pressing the contained reduced iron downward. As described above, reduced iron stored in the storage unit (700) for a long time or temporarily may undergo aggregation due to its own weight while remaining in the storage unit (700), and the aggregation degree evaluation unit (900) evaluates the aggregation degree of the reduced iron in advance to minimize such aggregation within the storage unit (700). Accordingly, the reactor (910) can pressurize the reduced iron by simulating the pressure applied to the reduced iron stored in the storage unit (700) through the pressurizing member. At this time, the reactor (910) can pressurize the contained reduced iron by simulating the pressure applied to the reduced iron stored in the lower part of the storage space of the storage unit (700). Since the maximum pressure is applied to the reduced iron stored at the bottom of the storage space of the storage unit (700), for example, at the bottom of the storage space, due to the load of the reduced iron stored above it, the reactor (910) can obtain a more reliable coagulation degree evaluation result in the subsequent process by pressurizing the pressure at which coagulation occurs most actively.

[0056] The separator (920) receives the reduced iron powder treated with pressure in the reactor (910) and can separate the aggregated reduced iron powder with a particle size greater than a set particle size. For example, the separator (920) receives the reduced iron powder treated with pressure in the reactor and can separate the reduced iron powder with a particle size of 20 mm or more by considering it as aggregated. However, this is for illustrative purposes only, and the set particle size can be set differently in various ways.

[0057] Such a separator (920) can separate aggregated reduced iron in various ways. For example, the separator (920) can receive reduced iron that has been pressurized in the reactor (910) and separate aggregated reduced iron by sieving the received reduced iron. In addition, the separator (920) can receive reduced iron that has been pressurized in the reactor (910) and rotate it horizontally to separate aggregated reduced iron by centrifugal force.

[0058] The calculator (930) measures the mass of the aggregated reduced iron and calculates the degree of aggregation. At this time, the calculator (930) measures the mass of the reduced iron supplied from the reduction unit (400) to the reactor (910), the mass of the reduced iron contained in the reactor (910), or the mass of the reduced iron supplied to the separator (920) to obtain information regarding the total mass of the reduced iron, i.e., the total mass of the reduced iron subjected to pressurization treatment, and measures the mass of the aggregated reduced iron separated through the separator (920) to obtain information regarding the mass of the aggregated reduced iron, and then calculates the degree of aggregation according to the following mathematical formula.

[0059] [Mathematical Formula]

[0060]

[0061] The control unit (1000) can receive information regarding the degree of cohesion from the degree of cohesion evaluation unit (900) and adjust the amount of auxiliary material supplied by the first auxiliary material supply unit (200). The degree of cohesion calculated according to the above mathematical formula indicates that a higher value indicates that a large amount of cohesion may occur within the storage unit (700), and a lower value indicates that the likelihood of cohesion occurring within the storage unit (700) is low. Accordingly, if the degree of cohesion is higher than the set value, the control unit (1000) can increase the amount of auxiliary material supplied by the first auxiliary material supply unit (200) to the reduction unit (400) compared to before the degree of cohesion evaluation. For example, if the degree of cohesion is higher than 20%, the control unit (1000) can increase the amount of auxiliary material supplied by the first auxiliary material supply unit (200) to the reduction unit (400) compared to before the degree of cohesion evaluation. At this time, if the first auxiliary material supply unit (200) was not supplying auxiliary materials to the reduction unit (400) before evaluating the degree of cohesion, the control unit (1000) can adjust the first auxiliary material supply unit (200) to supply auxiliary materials to the reduction unit (400) after evaluating the degree of cohesion, and if the first auxiliary material supply unit (200) was supplying a first set amount of auxiliary materials before evaluating the degree of cohesion, the control unit (1000) can adjust the first auxiliary material supply unit (200) to supply a second set amount of auxiliary materials to the reduction unit (400) which is greater than the first set amount after evaluating the degree of cohesion. In this way, the control unit (1000) can also adjust the amount of powder raw materials supplied by the powder raw material supply unit (100).

[0062] Meanwhile, the control unit (1000) can also adjust the amount of auxiliary raw material supplied by the second auxiliary raw material supply unit (800). At this time, the control unit (1000) can adjust the amount of auxiliary raw material supplied by the second auxiliary raw material supply unit (800) so that the total amount of auxiliary raw material supplied by the first auxiliary raw material supply unit (200) and the second auxiliary raw material supply unit (800) is maintained within a set range. As described above, auxiliary raw materials such as limestone (CaCO3) and dolomite (CaCO3·MgCO3) play a role in improving the flowability of the slag generated when reducing iron is melted in an electric furnace. At this time, in order to improve the flowability of the slag, the total amount of auxiliary raw materials supplied to the melting section (600) via the reduction section (400) or supplied directly to the melting section (600) needs to be controlled within a set range. Therefore, to prevent the total amount of auxiliary raw materials finally supplied to the melting section (600) from being supplied excessively beyond the set range, the control section (1000) can adjust the amount of auxiliary raw materials supplied by the second auxiliary raw material supply section (800). For example, the control section (1000) can adjust the amount of auxiliary raw materials supplied by the first auxiliary raw material supply section (200) and the second auxiliary raw material supply section (800) so that when the total mass of the powder raw materials supplied to the reduction section (400) is 100 mass%, the auxiliary raw materials are supplied to the melting section (600) in a total amount of 10 to 50 mass%. However, this is for illustrative purposes only, and the total amount of auxiliary materials supplied to the melting section (600) can be set differently, of course.

[0063]

[0064] Hereinafter, a method for manufacturing molten iron according to an embodiment of the present invention will be described. The method for manufacturing molten iron according to an embodiment of the present invention may be a method for manufacturing molten iron using the aforementioned molten iron manufacturing equipment, and since the aforementioned details regarding the molten iron manufacturing equipment may be applied as is, the description of redundant details will be omitted.

[0065] FIG. 3 is a diagram schematically illustrating a method for manufacturing molten iron according to an embodiment of the present invention.

[0066] Referring to FIG. 3, a method for manufacturing molten iron according to an embodiment of the present invention comprises the steps of: supplying a powder raw material to a reduction unit (400) (S100); reducing the powder raw material in the reduction unit (100) to produce powdered reduced iron (S200); evaluating the degree of agglomeration of the produced powdered reduced iron (S300); receiving information regarding the evaluated degree of agglomeration and adjusting the amount of auxiliary raw material to be supplied to the reduction unit (400) (S400); and supplying the powder raw material and the adjusted amount of auxiliary raw material to the reduction unit (400) to produce powdered reduced iron, moving it to a melting unit (600), and melting it (S500).

[0067] The process (S100) of supplying powder raw materials to the reduction unit (400) involves supplying powder raw materials to the reduction unit (400) through the powder raw material supply unit (100). Here, the powder raw materials may include, for example, iron ore in powder form having a particle size greater than 0 mm and less than or equal to 8 mm, i.e., powdered iron ore. In this case, it goes without saying that no auxiliary raw materials may be supplied to the reduction unit (400). Alternatively, the process (S100) of supplying powder raw materials to the reduction unit (400) may include a process of supplying auxiliary raw materials to the reduction unit (400). This is performed through the first auxiliary raw material supply unit (200), and the auxiliary raw materials may include at least one of powdered limestone (CaCO3) and powdered dolomite (CaCO3·MgCO3), and the auxiliary raw materials may be supplied to the reduction unit (400) in, for example, a first set amount.

[0068] The process of manufacturing powdered reduced iron (S200) involves reducing powdered raw materials in a reduction section (400) to produce powdered reduced iron. The process of manufacturing powdered reduced iron (S200) may include a process of supplying a reducing gas to the reduction section (400) and a process of reducing powdered raw materials by reacting them with the reducing gas.

[0069] The process of supplying reducing gas is performed by the reducing gas supply unit (300) supplying reducing gas to the reducing unit (400). Here, the reducing gas may include hydrogen gas, and the hydrogen gas may be included in a ratio of 80 to 100% of the total reducing gas. The process of supplying reducing gas is performed by the reducing gas supply unit (300) supplying reducing gas to the reducing unit (400) through a reducing gas supply line that interconnects the reducing gas supply unit (300) and the reducing unit (400). At this time, the amount of reducing gas supplied to the reducing unit (400) during the process of supplying reducing gas can be controlled to a range of at least 2 times and no more than 3 times the amount required to reduce all the powder raw materials supplied to the reducing unit (400).

[0070] The process of supplying the reducing gas can be to heat the reducing gas to a temperature of 800 to 1200°C and supply it to the reducing section (400). When hydrogen gas is used as the reducing gas, the hydrogen gas reacts with the iron ore supplied to the reducing section (400) to produce reduced iron. Since the reaction between the iron ore and the hydrogen gas is a strong endothermic reaction, the hydrogen gas supplied to the reducing section (400) can be heated to a temperature of 800°C or higher, more suitably 850°C or higher, and the reaction efficiency can be improved by supplying the reducing gas heated in this way.

[0071] In the process of reducing powder raw materials by reacting them with a reducing gas, the reducing unit (400) receives raw materials from the powder raw material supply unit (100) and receives reducing gas from the reducing gas supply unit (30), thereby reducing the powdered iron ore by reacting it with the reducing gas. The reducing unit (400) may include a reduction furnace having a reduction space capable of producing reduced iron using the reducing gas. While the reduction furnace may be provided as a single unit, as previously mentioned, multiple reduction furnaces may be connected to effectively reduce low-grade powdered iron ore with a low iron content, allowing the powdered raw materials to be moved sequentially to produce reduced iron.

[0072] Meanwhile, in the process of reducing powder raw materials by reacting them with reducing gas, a large amount of byproducts are generated in addition to the reduced iron powder. The byproducts generated and discharged from the reduction section (400) may include water vapor produced by the reaction of iron powder ore with hydrogen gas, hydrogen gas that did not react with the powder raw materials, and nitrogen gas supplied as purge gas. Such byproducts may move along the flow of reducing gas within the reduction section (400) and be discharged from the reduction furnace.

[0073] In this way, the byproduct discharged from the reduction furnace can be used to produce hydrogen gas. As described above, the byproduct discharged from the reduction unit (400) includes water vapor, hydrogen gas, and nitrogen gas, and an extraction unit (500) is connected to the reduction unit (400) to receive the byproduct discharged from the reduction unit (400). The extraction unit (500) can extract hydrogen gas from the supplied byproduct using a pressure swing adsorption method.

[0074] The extracted hydrogen gas can be used for various purposes. However, the reduction unit (400) uses hydrogen gas to reduce the raw material, i.e., iron ore, and since hydrogen gas is a very expensive gas, it is used in a large amount, more than twice the amount required to reduce all the raw material supplied to the reduction unit (400), so the hydrogen gas extracted from the extraction unit (500) can be reused as a reduction gas to reduce iron ore in order to reduce costs through resource recycling.

[0075] The process (S300) for evaluating the degree of cohesion evaluates the degree of cohesion of the reduced iron produced in the reduction unit (400). This can be performed by the cohesion evaluation unit (900) receiving at least a portion of the reduced iron produced from the reduction unit (400). For example, the cohesion evaluation unit (900) evaluates the degree of cohesion by receiving a portion of the reduced iron produced from the reduction unit (400), and separately, the remainder of the reduced iron produced from the reduction unit (400), i.e., the remaining reduced iron, can be stored in the storage unit (700), supplied to the dissolution unit (600), and then dissolved. Additionally, as previously mentioned, the cohesion evaluation unit (900) may evaluate the degree of cohesion by receiving the entire amount of the reduced iron produced from the reduction unit (400).

[0076] The process (S300) for evaluating the degree of aggregation, as described above, may include a process of pressurizing the manufactured reduced iron, a process of separating aggregated reduced iron with a particle size greater than a set size from the pressurized reduced iron, and a process of measuring the mass of the aggregated reduced iron to calculate the degree of aggregation. That is, the aggregation evaluation unit (900) includes a reactor (910), a separator (920), and a calculator (930). In the reactor (910), a process of pressurizing the manufactured reduced iron is performed; in the separator (920), a process of separating aggregated reduced iron with a particle size greater than a set size from the pressurized reduced iron is performed; and in the calculator (930), a process of measuring the mass of the aggregated reduced iron to calculate the degree of aggregation may be performed.

[0077] The process of pressurizing the reduced iron can be performed by pressurizing the reduced iron contained in the reactor (910) downward through a pressurizing member installed in the reactor (910). Here, the process of pressurizing the reduced iron can be performed by simulating the pressure applied to the reduced iron during the process of storing the reduced iron through the storage unit (700) to supply the reduced iron to the melting unit (600) as described later. That is, since the maximum pressure is applied to the reduced iron stored at the bottom of the storage space of the storage unit (700), for example, at the very bottom of the storage space, due to the load of the reduced iron stored above it, the reactor (910) pressurizes the reduced iron contained in the receiving space by simulating the maximum pressure applied by the load of the reduced iron stored above it, thereby obtaining a more reliable coagulation evaluation result in the subsequent process.

[0078] The process of separating aggregated reduced iron involves separating aggregated reduced iron with a particle size greater than a set size from the reduced iron treated under pressure in the reactor (910). The process of separating aggregated reduced iron can be performed in various ways; for example, the separator (920) may receive the reduced iron treated under pressure in the reactor (910) and separate the aggregated reduced iron by sieving the received reduced iron. Additionally, as previously mentioned, the separator (920) may receive the reduced iron treated under pressure in the reactor (910) and rotate it horizontally to separate the aggregated reduced iron by centrifugal force.

[0079] The process of calculating the degree of aggregation involves measuring the mass of aggregated reduced iron separated from the separator (920) to calculate the degree of aggregation. For example, the calculator (930) measures the mass of reduced iron supplied from the reduction section (400) to the reactor (910), the mass of reduced iron contained in the reactor (910), or the mass of reduced iron supplied to the separator (920) to obtain information regarding the total mass of reduced iron, i.e., the total mass of reduced iron subjected to pressurization, and measures the mass of aggregated reduced iron separated through the separator (920) to obtain information regarding the mass of aggregated reduced iron, and then calculates the mass fraction of aggregated reduced iron relative to the total mass of reduced iron subjected to pressurization according to the aforementioned mathematical formula to calculate the degree of aggregation.

[0080] The process of adjusting the amount of auxiliary raw material to be supplied to the reduction unit (400) (S400) receives information regarding the degree of cohesion evaluated in the process of evaluating the degree of cohesion (S300) and adjusts the amount of auxiliary raw material to be supplied to the reduction unit (400). This can be performed through the control unit (1000), and if the degree of cohesion is higher than the set value, the control unit (1000) can increase the amount of auxiliary raw material supplied by the first auxiliary raw material supply unit (200) to the reduction unit (400) compared to before the degree of cohesion was evaluated. At this time, if the first auxiliary material supply unit (200) was not supplying auxiliary materials to the reduction unit (400) before evaluating the degree of cohesion, the control unit (1000) can adjust the first auxiliary material supply unit (200) to supply auxiliary materials to the reduction unit (400) after evaluating the degree of cohesion, and if the first auxiliary material supply unit (200) was supplying a first set amount of auxiliary materials before evaluating the degree of cohesion, the control unit (1000) can adjust the first auxiliary material supply unit (200) to supply a second set amount of auxiliary materials to the reduction unit (400) that is greater than the first set amount after evaluating the degree of cohesion.

[0081] The melting process (S500) involves transferring the reduced iron produced in the reduction section (400) to the melting section (600) to melt it. That is, the melting section (600) can receive the reduced iron from the reduction section (400) through the storage section (700) and heat it to melt it. At this time, the melting process (S500) can be performed by receiving the reduced iron from the reduction section (500) and melting the received reduced iron using heat generated through electric energy. At this time, the melting section (600) may include an electric furnace having a melting space capable of melting the reduced iron using electric heat. Such an electric furnace may include an ESF (Electric Smelting Furnace) or SAF (Submerged Arc Furnace) that is immersed in slag and can melt the reduced iron using slag resistance heat.

[0082] The dissolving process (S500) can be performed by supplying powdered raw materials to the reduction section (400) and an amount of auxiliary raw materials, the amount of which is adjusted after evaluating the degree of agglomeration, to move the powdered reduced iron produced by supplying the powdered raw materials and an adjusted amount of auxiliary raw materials to the reduction section (400) to the dissolving section (600) and to dissolve it. Here, the dissolving process (S500) may include a process of storing the powdered reduced iron produced by supplying the powdered raw materials and an adjusted amount of auxiliary raw materials to the reduction section (400), and a process of supplying the stored powdered reduced iron to the dissolving section (600). As previously mentioned, the process of storing the powdered reduced iron is performed through a storage section (700), and the storage section (700) may be installed to be movable between the reduction section (400) and the dissolving section (600) to receive and store the powdered reduced iron from the reduction section (400) including a hopper, and to supply the stored powdered reduced iron to the dissolving section (600).

[0083] Meanwhile, the dissolving process (S500) includes a process of supplying auxiliary materials to the dissolving unit (600), and the process of supplying auxiliary materials to the dissolving unit (600) can supply auxiliary materials to the dissolving unit (600) through the second auxiliary material supply unit (800) so that the total amount of auxiliary materials supplied to the reducing unit (400) and the dissolving unit (600) is maintained within a set range. That is, the aforementioned control unit (1000) can also adjust the amount of auxiliary materials supplied by the second auxiliary material supply unit (800), and the control unit (1000) can adjust the amount of auxiliary materials supplied by the second auxiliary material supply unit (800) so that the total amount of auxiliary materials supplied by the first auxiliary material supply unit (200) and the second auxiliary material supply unit (800) is maintained within a set range. This is because, in order to improve the flowability of the slag, the total amount of auxiliary raw materials supplied to the melting section (600) via the reduction section (400) or supplied directly to the melting section (600) needs to be controlled within a set range. In order to prevent the total amount of auxiliary raw materials finally supplied to the melting section (600) from being supplied excessively beyond the set range, the process of supplying auxiliary raw materials to the melting section (600) can supply auxiliary raw materials to the melting section (600) such that the total amount of auxiliary raw materials supplied to the reduction section (400) and the melting section (600) is maintained within the set range.

[0084]

[0085] In the foregoing, preferred embodiments of the present invention have been described and illustrated using specific terms, but such terms are intended solely to clarify the present invention, and it is obvious that various modifications and changes may be made to the embodiments and described terms of the present invention without departing from the technical spirit and scope of the following claims. Such modified embodiments should not be understood separately from the spirit and scope of the present invention, but should be considered to fall within the scope of the claims of the present invention.

Claims

1. A reduction section capable of producing powdered reduced iron by reducing powdered raw materials; A melting section capable of melting the above-mentioned reduced iron; A first auxiliary material supply unit installed to supply auxiliary materials to the above-mentioned reduction unit; A cohesion evaluation unit capable of evaluating the degree of cohesion by receiving at least a portion of the reduced iron from the above-mentioned reduction unit; and A molten iron manufacturing facility comprising: a control unit capable of receiving information regarding the degree of cohesion from the above-mentioned cohesion evaluation unit and adjusting the amount of auxiliary material supplied by the above-mentioned first auxiliary material supply unit.

2. In Claim 1, The above control unit is a molten iron manufacturing facility that, if the degree of cohesion is higher than the set value, increases the amount of auxiliary material supplied by the first auxiliary material supply unit compared to before the degree of cohesion is evaluated.

3. In Claim 2, It further includes a second auxiliary material supply unit installed to supply auxiliary materials to the melting unit above, and The above control unit is a molten iron manufacturing facility that adjusts the amount of auxiliary material supplied by the second auxiliary material supply unit so that the total amount of auxiliary material supplied by the first auxiliary material supply unit and the second auxiliary material supply unit is maintained within a set range.

4. In Claim 1, The above cohesion evaluation unit is, A reactor having a receiving space capable of accommodating at least a portion of the reduced iron produced in the above-mentioned reduction section, and capable of pressurizing the reduced iron accommodated in the receiving space; A separator capable of receiving reduced iron powder pressurized in the above reactor and separating aggregated reduced iron powder with a particle size greater than or equal to a set particle size; and A molten iron manufacturing facility comprising: a calculator capable of measuring the mass of the above-mentioned aggregated reduced iron and calculating the degree of aggregation according to the following mathematical formula. [Mathematical Formula] 5. In Claim 4, It further includes a storage unit having a storage space capable of receiving and storing the reduced iron produced in the reduction unit, and capable of supplying the reduced iron stored in the storage space to the melting unit. The above reactor is a molten iron manufacturing facility that pressurizes the reduced iron by simulating the pressure applied to the reduced iron stored in the lower part of the storage space.

6. In Claim 5, The above storage unit is a molten iron manufacturing facility installed to be movable between the above reduction unit and melting unit.

7. In Claim 1, The above reduction unit includes a plurality of reduction furnaces installed to sequentially reduce powder raw materials while moving them. The above melting section comprises an electric furnace having a melting space capable of melting the reduced iron produced in the above reduction section; a molten iron manufacturing facility.

8. Process of supplying powder raw materials to the reduction section; A process of producing powdered reduced iron by reducing powder raw materials in the above-mentioned reduction section; Process for evaluating the cohesion of manufactured reduced iron powder; A process of receiving information regarding the evaluated degree of cohesion and adjusting the amount of auxiliary raw material to be supplied to the reduction unit; and A method for producing molten iron comprising the process of supplying powdered raw materials and a controlled amount of auxiliary raw materials to the reduction section, moving the produced powdered reduced iron to the melting section, and melting it.

9. In Claim 8, A method for producing molten iron, wherein the above-mentioned powder raw material comprises iron ore having a particle size greater than 0 mm and less than or equal to 8 mm.

10. In Claim 8, The process of manufacturing the above-mentioned reduced iron is, A method for manufacturing molten iron comprising the process of reducing powder raw materials by supplying hydrogen gas to the reduction section.

11. In Claim 8, The process of evaluating the above cohesion is, The process of pressurizing the manufactured iron powder; A process for separating aggregated reduced iron with a set particle size or larger from pressurized reduced iron; and A method for producing molten iron comprising the process of measuring the mass of aggregated reduced iron and calculating the degree of aggregation according to the following mathematical formula. [Mathematical Formula] 12. In claim 8, The above dissolving process is, A process of storing powdered reduced iron produced by supplying powdered raw materials and a controlled amount of auxiliary raw materials to the above-mentioned reduction section; and The process of supplying the stored reduced iron to the melting section; is included, The process of pressurizing the above-mentioned reduced iron is a method for manufacturing molten iron that pressurizes the above-mentioned reduced iron by simulating the maximum pressure applied to the above-mentioned reduced iron during the storage process of the above-mentioned reduced iron.

13. In claim 8, A method for manufacturing molten iron, wherein the process of controlling the amount of auxiliary raw material to be supplied to the reduction section is such that if the evaluated cohesion level is higher than a set value, the amount of auxiliary raw material to be supplied to the reduction section is increased compared to before the cohesion level was evaluated.

14. In Claim 13, The above dissolving process is, The process of supplying auxiliary materials to the above-mentioned melting section; is included, A method for manufacturing molten iron, wherein the process of supplying auxiliary materials to the melting section is such that the total amount of auxiliary materials supplied to the reduction section and the melting section is maintained within a set range.

15. In Claim 8, A method for producing molten iron, wherein the above auxiliary raw material comprises at least one of powdered limestone and powdered dolomite.

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