Blast furnace operation method and blast furnace operation apparatus

Abstract

The present invention relates to a blast furnace operation method and a blast furnace operation apparatus applied thereto, the method comprising the steps of: preparing an iron-containing material (M) and coke (C) as charging materials to be charged in a blast furnace; determining the charging amounts of (M) and (C) according to the amount of reduced iron-containing material contained in (M), the charging ratio (M / C) of (M) to (C) being greater than a predetermined standard charging ratio (MS / CS); charging the charging materials in the blast furnace according to the determined charging amounts; and manufacturing molten iron from the charging materials. The disclosed the blast furnace operation method and blast furnace operation apparatus can improve operation efficiency.

Description

Blast furnace operation method and blast furnace operation device

[0001] The present invention relates to a blast furnace operating method and a blast furnace operating device, and more particularly, to a blast furnace operating method and a blast furnace operating device capable of improving operating efficiency.

[0002] Typically, conventional blast furnace-based ironmaking processes (hereinafter referred to as "blast furnace operations" or "ironmaking operations") use sintered ore, sintered ore, and pellets as iron sources. These iron sources, composed of iron oxide, require reduction and melting in a blast furnace to be converted into molten iron. Consequently, blast furnace operations consume a significant amount of coke, corresponding to the energy required for reduction and melting, and consequently generate a significant amount of carbon dioxide.

[0003] Recently, research and development are being conducted on low-carbon blast furnace operations, part of carbon-neutral technologies aimed at minimizing carbon emissions to address the climate change crisis. However, simply replacing some or all of the iron oxide source with reduced iron for low-carbon blast furnace operation raises the furnace top temperature and reduces the blast furnace's gas utilization rate, significantly reducing operational efficiency.

[0004] The technology underlying the present invention is disclosed in the following patent documents.

[0005] (Patent Document 1) KR10-2176345 B1

[0006] (Patent Document 2) KR10-1891196 B1

[0007] The present invention provides a blast furnace operating method and a blast furnace operating device capable of improving operating efficiency.

[0008] A blast furnace operating method according to an embodiment of the present invention comprises the steps of preparing an iron-containing material (M) and coke (C) as charges to be charged into a blast furnace; a charging ratio (M / C) of the iron-containing material (M) and the coke (C) is a predetermined standard charging ratio (M S / C S ) and a process of determining the amount of the iron-containing material (M) and coke (C) to be charged according to the amount of reduced iron-containing material included in the iron-containing material (M); a process of charging the charge into the blast furnace according to the determined amount of charge; and a process of manufacturing molten iron from the charge.

[0009] The process of preparing the above iron-containing material (M) and coke (C) may include a process of preparing a plurality of hoppers; and a process of receiving the iron oxide-containing material and the reduced iron-containing material as the iron-containing material (M) and the coke (C) in each of the plurality of hoppers.

[0010] The reduced iron-containing material may include at least one of pre-reduced scrap, hot briquetted iron (HBI), hot compacted iron (HCI), low reduced iron (LRI), and direct reduced iron (DRI).

[0011] The process of determining the charging amount of the above iron-containing material (M) and coke (C) is to determine the charging ratio of the iron-containing material and coke when the iron-containing material (M) contains only iron oxide-containing material, and the charging ratio of the iron oxide-containing material and coke is the standard charging ratio (M). S / C S ) and the process of determining the standard loading ratio (M S / C S ) to be 0.2 to 0.4 greater than the charging ratio (M / C); and a process of determining the charging amount of the iron-containing material (M) and coke (C) according to the charging ratio (M / C).

[0012] The process of determining the above charging ratio (M / C) may include a process of modifying the charging ratio (M / C) in proportion to the amount of reduced iron-containing material included in the iron-containing material (M).

[0013] The process of charging the above-mentioned charge into the blast furnace may include a process of repeatedly discharging the iron oxide-containing material, the reduced iron-containing material, and the coke (C) sequentially from the plurality of hoppers according to a predetermined discharge order; and a process of repeatedly charging the iron oxide-containing material, the reduced iron-containing material, and the coke (C) into the blast furnace according to the discharge order to form multiple layers, and controlling the position of the reduced iron-containing material.

[0014] The process of sequentially and repeatedly discharging from the above multiple hoppers may include a process of discharging the reduced iron-containing material before the iron oxide-containing material.

[0015] The process of controlling the position of the reduced iron-containing material may include: a process of controlling the radial position of the reduced iron-containing material so that the reduced iron-containing material is concentrated in the inner wall region among the inner wall region and the central region of the blast furnace throughout the multiple layers; and a process of controlling the vertical position of the reduced iron-containing material so that the reduced iron-containing material is concentrated below the iron oxide-containing material in each layer.

[0016] The process of controlling the radial position of the reduced iron-containing material may include a process of distributing 65% of the total charging amount of the reduced iron-containing material to an area of ​​100% to 70% of the radius of the blast furnace from the inner wall to the center of the blast furnace.

[0017] The process for manufacturing the above molten iron may include a process of burning the coke by blowing hot air into the inside of the blast furnace; a process of melting the iron oxide-containing material using combustion heat and combustion gas; and a process of melting the reduced iron-containing material using combustion heat and combustion gas.

[0018] A blast furnace operating device according to an embodiment of the present invention comprises: a blast furnace; a charge supply unit installed to charge an iron-containing material (M) and coke (C) as charges into the blast furnace; a charge ratio (M / C) of the iron-containing material (M) and the coke (C) is a predetermined standard charge ratio (M S / C S ) and includes a charge amount determining unit for determining the charge amount of the iron-containing material (M) and coke (C) according to the amount of reduced iron-containing material included in the iron-containing material (M); and a control unit for controlling the operation of the charge supply unit so that the charge can be charged into the blast furnace according to the charge amount determined by the charge amount determining unit.

[0019] The above-mentioned charge supply unit may include a plurality of hoppers in which the iron-containing material (M), the iron oxide-containing material, the reduced iron-containing material, and the coke (C) are formed to be able to be stored and discharged therein, respectively; feeders installed in each of the plurality of hoppers and whose opening and closing operations are controlled by the control unit; and a conveyor installed to connect the plurality of hoppers and the blast furnace and whose conveying operation is controlled by the control unit.

[0020] The above charging amount determination unit determines the standard charging ratio (M) in advance based on the operation history data. S / C S ) is stored in a storage device; using the operating condition information of the currently operating loading material and the operating history data, multiple standard loading ratios (M S / C S ) among the standard loading ratios (M) to be used in the current operation S / CS ) selector; and the above reference loading ratio (M S / C S ) to be 0.2 to 0.4 greater than the charging ratio (M / C), and a determining device for determining the charging amount of the iron-containing material (M) and coke (C) according to the charging ratio (M / C).

[0021] The above-mentioned determination device can modify the charging ratio (M / C) determined in proportion to the amount of reduced iron-containing material included in the iron-containing material (M) currently in operation.

[0022] The above standard loading ratio (M S / C S ) may be the charging ratio of the iron oxide-containing material and coke when the iron-containing material (M) contains only iron oxide-containing material.

[0023] The above control unit can control the discharge amount of each feeder so that the charge can be charged into the blast furnace according to the determined charge amount, and can control the operating order of each feeder and the conveying speed of the conveyor so as to control the radial position and the vertical position of the reduced iron-containing material inside the blast furnace.

[0024] According to an embodiment of the present invention, when charging iron-containing material (M) and coke (C) into a blast furnace for blast furnace operation, the charging ratio (M / C) of iron-containing material (M) and coke (C) is a predetermined standard charging ratio (M S / C S) is larger than, and the amount of the iron-containing material (M) and coke (C) can be determined according to the amount of the reduced iron-containing material included in the iron-containing material (M), and the iron-containing material (M) and coke (C) can be charged into the blast furnace with the determined amount of charging, and molten iron can be manufactured therefrom. Accordingly, the heat flow ratio in the blast furnace can be prevented from being lowered by the reduced iron-containing component, thereby improving the thermal efficiency in the blast furnace, and at the same time, the ventilation of the charging material in the blast furnace can be secured, thereby improving the stability of operation. Therefore, the operational efficiency of the blast furnace can be effectively improved.

[0025] Figure 1 is a schematic diagram of a blast furnace operating device according to an embodiment of the present invention.

[0026] Figure 2 is a flow chart of a blast furnace operation method according to an embodiment of the present invention.

[0027] FIG. 3 is a schematic diagram illustrating a location where a reduced iron-containing material is charged in a blast furnace operation according to an embodiment of the present invention.

[0028] FIG. 4 is a drawing to show the effect of the vertical position of charging of a reduced iron-containing material in a blast furnace operation according to an embodiment of the present invention, in comparison with a comparative example.

[0029] FIG. 5 is a drawing for explaining the effect of the vertical position of the charging of a reduced iron-containing material in a blast furnace operation according to an embodiment of the present invention, in comparison with a comparative example.

[0030] FIG. 6 is a drawing for exemplifying the relationship between the order of discharge of iron oxide-containing material, reduced iron-containing material, and coke and the vertical position of the reduced iron-containing material in a blast furnace operation according to an embodiment of the present invention.

[0031] FIG. 7 is a drawing for exemplifying the relationship between the order of discharge of iron oxide-containing material, reduced iron-containing material, and coke and the radial position of the reduced iron-containing material in a blast furnace operation according to an embodiment of the present invention.

[0032] FIG. 8 is a drawing for exemplifying a decrease in heat flow ratio according to the amount of reduced iron-containing material charged in a blast furnace operation according to an embodiment of the present invention.

[0033] FIG. 9 is a drawing for exemplifying changes in differential pressure within a blast furnace depending on whether or not a reduced iron-containing material is charged in a blast furnace operation according to an embodiment of the present invention.

[0034] 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. These embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully convey the scope of the invention to those skilled in the art. To illustrate the embodiments of the present invention, the drawings may be exaggerated, and like reference numerals in the drawings represent like elements.

[0035] The present invention relates to a blast furnace operating method and a blast furnace operating device. Hereinafter, an embodiment of the present invention will be described in detail by exemplifying a case where the blast furnace operating method and the blast furnace operating device are applied to low-carbon blast furnace operation using an iron oxide-containing material and a reduced iron-containing material.

[0036] Before explaining a blast furnace operation method according to an embodiment of the present invention, a blast furnace operation facility to which the blast furnace operation method is applied will be explained.

[0037] Figure 1 is a schematic diagram of a blast furnace operating device according to an embodiment of the present invention.

[0038] Referring to FIG. 1, a blast furnace operating device according to an embodiment of the present invention comprises a blast furnace (100), a charge supply unit (200) installed to charge iron-containing material (M) and coke (C) as charges (M, C) into the blast furnace (100), and a charging ratio (M / C) of iron-containing material (M) and coke (C) set in advance as a standard charging ratio (M). S / CS ) and includes a charge amount determining unit (300) for determining the charge amount of the iron-containing material (M) and coke (C) according to the amount of reduced iron-containing material included in the iron-containing material (M), and a control unit (400) for controlling the operation of the charge material supply unit (200) so that the charge material (M, C) can be charged into the blast furnace (100) according to the charge amount determined by the charge amount determining unit (300).

[0039] In addition, the blast furnace operating device according to an embodiment of the present invention may include a hot air supply unit (500) installed in a ring shape by surrounding the lower part of the blast furnace (100) in a circumferential direction (θ) from the outside of the blast furnace (100) so as to supply hot air to the blast furnace (100).

[0040] The charge (M, C) may include an iron-containing material (M) and coke (C). Here, the iron-containing material (M) may include an iron oxide-containing material and a reduced iron-containing material. The iron oxide-containing material may include sintered ore, pellets, and sintered ore. Here, the sintered ore may include large-grained sintered ore and small-grained sintered ore. In addition, the pellets may include large-grained pellets and small-grained pellets. Similarly, the sintered ore may include large-grained sintered ore and small-grained sintered ore.

[0041] Here, a particle size of 10 mm or larger can be considered a large particle, while a particle size smaller than this can be considered a small particle. Of course, the criteria for distinguishing between large and small particles can vary. For example, a particle size of 8 mm or larger can be classified as large, while a particle size smaller than this can be classified as small.

[0042] The reduced iron-containing material may include at least one of pre-reduced scrap, hot briquetted iron (HBI), hot compacted iron (HCI), low reduced iron (LRI), and direct reduced iron (DRI). Meanwhile, the reduced iron-containing material does not distinguish between large and small particle sizes.

[0043] A blast furnace (100) serves to manufacture molten iron (L) by charging the charge (M, C). The blast furnace (100) has an internal space for manufacturing molten iron (L) by charging the charge (M, C), and may include a furnace body (110) extending in the vertical direction (V) and the radial direction (R), in which a charge inlet is formed at the top of the furnace, and tuyere (120) formed radially at multiple locations at the bottom of the furnace body (110) so as to be able to inject hot air and connected to a hot air supply unit (500).

[0044] In addition, the blast furnace (100) may include a furnace hopper (130) installed at the top of the furnace body (100) to deliver the charge (M, C), a distribution chute (140) disposed below the charge inlet of the furnace body (110), connected slantedly in the radial direction (R) to the lower portion of the furnace hopper (130), and capable of rotating in the circumferential direction (θ) so as to charge the charge (M, C) into the internal space of the furnace body (110) in the radial direction (R) and the circumferential direction (θ). Of course, the configuration of the blast furnace (100) may vary.

[0045] The charge supply unit (200) serves to charge iron oxide-containing material, reduced iron-containing material, and coke (C) into the furnace body (110) of the blast furnace (100). Accordingly, the charge supply unit (200) may be installed so as to charge iron oxide-containing material, reduced iron-containing material, and coke (C) into the blast furnace (100). In addition, the charge supply unit (200) may include a plurality of hoppers (210) in which iron oxide-containing material, reduced iron-containing material, and coke (C) are formed to be respectively stored and discharged therein, a feeder installed in each of the plurality of hoppers (210) and whose opening and closing operation is controlled by a control unit (400), and a conveyor (220) installed to connect the plurality of hoppers (210) and the blast furnace (100), and whose conveying operation is controlled by the control unit (400).

[0046] The multiple hoppers (210) may include, for example, an iron oxide hopper (211) in which iron oxide-containing material is stored, a reduced iron hopper (212) in which reduced iron-containing material is stored, and a coke hopper (213) in which coke (C) is stored.

[0047] At this time, there may be a plurality of iron oxide hoppers (211). For example, a plurality of iron oxide hoppers (211), for example, three or more, may be provided so that sintered ore, pellets, and sintered ore can be accommodated, respectively. That is, the number of iron oxide hoppers (211) may vary depending on the number of types of iron oxide-containing materials. Meanwhile, the number of types of iron oxide-containing materials may also be referred to as the number of iron oxide-containing materials.

[0048] In addition, the number of reduced iron hoppers (212) may be at least one. For example, the reduced iron hoppers (212) may be provided in at least one number so that at least one of pre-reduced scrap, high-temperature briquette iron (HBI), high-temperature lumped iron (HCI), low-reduced iron (LRI), and direct reduced iron (DRI) can be accommodated. That is, the number of reduced iron hoppers (212) may vary depending on the number of types of reduced iron-containing materials (i.e., the number of reduced iron-containing materials). In addition, when the number of types of reduced iron-containing materials is plural, the number of reduced iron hoppers (212) may be plural, and each reduced iron-containing material may be accommodated in each reduced iron hopper (212).

[0049] For example, the reduced iron-containing material may include pre-reduced scrap, high-temperature briquette iron (HBI), high-temperature lumped iron (HCI), low-reduced iron (LRI), and direct reduced iron (DRI). Accordingly, the number of reduced iron hoppers (212) may be plural, for example, 5 or more, and each hopper may accommodate reduced iron-containing materials classified by type.

[0050] Hereinafter, an embodiment will be described by exemplifying that the number of reduced iron hoppers (212) is one and high temperature briquette iron (HBI) as a reduced iron-containing material is accommodated in the reduced iron hopper (212). However, the present invention is not limited thereto, and the number of reduced iron hoppers (212) and the number of types of reduced iron-containing materials may each be plural. In addition, the contents described below may be similarly or identically applied even when the number of reduced iron hoppers (212) and the number of types of reduced iron-containing materials each are plural. Meanwhile, the coke hopper (213) may be provided in one or more numbers.

[0051] The conveyor (220) may include, for example, a belt conveyor. The conveyor (220) may have one end connected to the upper portion of the road hopper (130) and the other end connected to multiple hoppers (210). The conveyor (220) may transport the materials discharged from the multiple hoppers (210) to the road hopper (130).

[0052] The charge supply unit (200) may further include an emission detector, which is disposed in at least one of the plurality of hoppers (210), feeders, and conveyors (220) and connected to the control unit (400), so as to detect the amounts of discharged iron oxide-containing material, reduced iron-containing material, and coke (C), respectively, and output the detection results to the control unit (400). In this case, the discharged amount may mean, for example, the discharged weight. In addition, the emission detector may include, for example, a load cell. Of course, the types of emission detectors may vary.

[0053] In addition, the charge supply unit (200) may include a discharge order detector which is disposed in at least one of the plurality of hoppers (210), feeders, and conveyors (220) and connected to the control unit (400) so as to detect the order in which iron oxide-containing material, reduced iron-containing material, and coke (C) are discharged and output the results to the control unit (400). Here, the discharge order may mean the order in which each charge is discharged from the hopper in which it is respectively contained. The discharge order detector may include, for example, an ultrasonic sensor, an image sensor, etc. The discharge amount and the discharge order for each type of charge detected by the discharge detector and the discharge order detector may be utilized for the control of the control unit (400).

[0054] The charge determination unit (300) determines the charge amount of the iron-containing material (M) and coke (C). Specifically, the charge determination unit (300) determines the charge ratio (M / C) of the iron-containing material (M) and coke (C) based on a predetermined standard charge ratio (M S / C S) and the amount of iron-containing material (M) and coke (C) can be determined according to the amount of reduced iron-containing material included in the iron-containing material (M).

[0055] To this end, the charging amount determination unit (300) determines a standard charging ratio (M) determined in advance for each operation history data. S / C S ) is stored in a storage device, and multiple standard loading ratios (M) are generated using the operating condition information and operating history data of the currently operating loading material. S / C S ) among the standard loading ratios (M) to be used in the current operation S / C S ) selector, and the standard loading ratio (M S / C S ) to be 0.2 to 0.4 greater than the charging ratio (M / C), and determine the charging amount of iron-containing material (M) and coke (C) according to the charging ratio (M / C), and may include a determining device that modifies the determined charging ratio (M / C) in proportion to the amount of reduced iron-containing material included in the iron-containing material (M) currently in operation.

[0056] The charging amount determination unit (300) can be connected to the control unit (400) and can transmit the determined charging ratio (M / C) or the modified charging ratio (M / C) to the control unit (400). Meanwhile, the standard charging ratio (M S / C S ) may be the charging ratio of iron oxide-containing material and coke when the iron-containing material (M) contains only iron oxide-containing material.

[0057] The control unit (400) controls the operation of the charge supply unit (200) so that the charge (M, C) can be charged into the blast furnace (100) according to the charge amount determined by the charge amount determination unit (300). To this end, the control unit (400) can control the discharge amount of each feeder so that the charge (M, C) can be charged into the blast furnace (100) according to the determined charge amount or the modified charge amount, and can control the operating order of each feeder and the conveying speed of the conveyor (220) so as to control the radial (R) position and the vertical (V) position of the reduced iron-containing material inside the blast furnace (100).

[0058] Of course, the control unit (400) also controls the overall operation of the blast furnace operation device. To this end, the control unit (400) can control the operation of the distribution chute (140) of the blast furnace (100) and the operation of the hot air supply unit (500). The configuration of the control unit (400) may vary. For example, the control unit (400) may be a type of process control computer.

[0059] A hot air supply unit (500) may be installed to supply hot air to the blast furnace (100). The hot air supply unit (500) may include an annular tube extending in the circumferential direction (θ) and surrounding the outer side of the lower portion of the furnace body (110), a blower tube extending from the annular tube to each tuyere, and a hot air supply device connected to the annular tube and supplying hot air to the annular tube. Of course, the configuration of the hot air supply unit (500) may vary.

[0060] Hereinafter, the operation of a blast furnace operating device according to an embodiment of the present invention will be described.

[0061] For example, the charge (M, C) can be provided by type in multiple hoppers (210) of the charge supply unit (200). Then, the charge (M, C) can be supplied from the charge supply unit (200) to the blast furnace (100). That is, by the control of the control unit (400), the feeder of the charge supply unit (200) can be operated, and the iron oxide-containing material, the reduced iron-containing material, and the coke (C) can be discharged from the multiple hoppers (210) to the conveyor (220) according to a predetermined discharge order. The conveyor (220) can transport these discharged charge (M, C) to the furnace top hopper (130) of the blast furnace (100).

[0062] Accordingly, the charge (M, C) can be supplied from the charge supply unit (200) to the furnace hopper (130). In addition, the charge (M, C) supplied to the furnace hopper (130) can be dropped along the distribution chute (140) and evenly charged in the radial direction (R) and the circumferential direction (θ) into the internal space of the furnace body (110), and can form multiple layers (A) within the furnace body (110) of the blast furnace (100). When the multiple layers (A) are formed within the furnace body (110) of the blast furnace (100) to a predetermined height, the charge (M, C) can be continuously supplied from the charge supply unit (200) to the blast furnace (100) while supplying hot air into the blast furnace (100) during this time, thereby manufacturing molten iron (L).

[0063] To this end, hot air can be supplied from the hot air supply unit (500) to the tuyere (120) of the blast furnace (100). The hot air supplied to the tuyere (120) can be injected into the internal space of the furnace body (110) to combust coke (C). When the coke (C) is combusted, combustion heat and combustion gas, such as carbon monoxide gas (hereinafter also referred to as 'reduction gas'), can be generated. Accordingly, the combustion heat and combustion gas can be used to melt and reduce the iron-containing material (M) in the charge (M, C). Specifically, as the combustion heat and combustion gas move from the bottom to the top of the furnace body (110) of the blast furnace (100), the iron oxide-containing material can be melted and reduced, and the reduced iron-containing material can be melted.

[0064] At this time, molten iron (L) can form a predetermined layer at the bottom of the furnace body (110) of the blast furnace (100). In addition, while the molten iron (L) is being manufactured, a core (B1), a loading zone (B2), and a fusion zone (B3) can be formed inside the furnace body (110) of the blast furnace (100) by injection of hot air. Melting and reduction of iron oxide-containing materials and melting of reduced iron-containing materials can mainly take place in the fusion zone (B3).

[0065] Meanwhile, as described above, the iron oxide-containing material is melted and reduced to produce molten iron. However, since the reduced iron-containing material is already reduced before being charged into the blast furnace (100), it can be melted inside the blast furnace (100) to produce molten iron. Since the reduced iron-containing material does not need to be reduced in this way, the energy required for reduction within the blast furnace can be reduced, thereby reducing the blast furnace reducing agent cost and reducing carbon dioxide emissions.

[0066] However, the effects of the reduced iron-containing material used to reduce carbon dioxide emissions on the operation inside the blast furnace (100) are as follows. The reduced iron-containing material can increase the furnace temperature in the upper part of the furnace body (110) of the blast furnace (100) and decrease the gas utilization rate, such as the carbon monoxide gas utilization rate. In addition, the reduced iron-containing material can reduce the wind pressure by thinning the fusion zone (B3) in the central part of the furnace body (110) of the blast furnace (100) and improve the ventilation inside the furnace body (110) of the blast furnace (100). In addition, the reduced iron-containing material can increase the molten iron temperature in the lower part of the furnace body (110) of the blast furnace (100) and increase the tapping ratio.

[0067] At this time, according to an embodiment of the present invention, the charging ratio (M / C) of the iron-containing material (M) and coke (C) is determined by using the charging amount determining unit (300) based on a predetermined standard charging ratio (M S / C S ) is larger than, and the amount of the iron-containing material (M) and coke (C) can be determined according to the amount of the reduced iron-containing material included in the iron-containing material (M). In addition, by charging the iron-containing material (M) and coke (C) into the blast furnace at the amount determined by the charge amount determination unit (300) using the control unit (400) and the charge supply unit (200), the adverse effects of the reduced iron-containing material in the upper part of the furnace body (110) of the blast furnace (100) can be prevented or suppressed, while the effect of the reduced iron-containing material in the middle and lower part of the furnace body (110) of the blast furnace (100) can be increased. Therefore, while reducing carbon dioxide generation by using the reduced iron-containing material, the operational efficiency and operational stability of the blast furnace operation can be improved.

[0068] In addition, according to an embodiment of the present invention, by using the control unit (400) and the charge supply unit (200), the discharge order can be adjusted according to the type of the charge (M, C), thereby controlling the radial position and the vertical position of the reduced iron-containing material inside the furnace body (110) of the blast furnace (100). Accordingly, the shape of the fusion zone (B3) can be smoothly induced into a desired shape, for example, an inverted 'V' shape, and the induced shape can be stably maintained. In addition, the dropping behavior of the melt of the reduced iron-containing material and the iron oxide-containing material can be controlled into a desired shape, and the assimilation of the melt generated from the reduced iron-containing material and the melt generated from the iron oxide-containing material can be improved. Therefore, the operational efficiency and operational stability of the blast furnace operation can be further improved.

[0069] Meanwhile, in order to avoid duplication of explanation, the specific operations of the charge supply unit (200), charge amount determination unit (300), and control unit (400) will be described together with the blast furnace operation method according to an embodiment of the present invention below.

[0070] Hereinafter, a blast furnace operation method according to an embodiment of the present invention will be described in detail. Figure 2 is a flowchart of a blast furnace operation method according to an embodiment of the present invention. In addition, Figure 3 is a schematic diagram illustrating the location where a reduced iron-containing material is charged in a blast furnace operation according to an embodiment of the present invention.

[0071] Referring to FIGS. 2 and 3, a blast furnace operation method according to an embodiment of the present invention comprises a process (S100) of preparing iron-containing material (M) and coke (C) as charges (M, C) to be charged into a blast furnace (100), and a charging ratio (M / C) of iron-containing material (M) and coke (C) that is a predetermined standard charging ratio (M). S / C S) and includes a process (S200) of determining the amount of iron-containing material (M) and coke (C) to be charged according to the amount of reduced iron-containing material included in the iron-containing material (M), a process (S300) of charging the charge into the blast furnace according to the determined amount of charge, and a process (S400) of manufacturing molten iron (L) from the charge (M, C).

[0072] At this time, the blast furnace operation method can be performed in a blast furnace operation device according to an embodiment of the present invention. Therefore, the following describes an embodiment by exemplifying that the blast furnace operation method is performed in a blast furnace operation device according to an embodiment of the present invention. However, the present invention is not limited thereto, and the blast furnace operation method can be performed in blast furnace operation devices of various structures. In other words, the contents described below can be applied similarly or identically even when the blast furnace operation method is applied to blast furnace operation devices of various structures.

[0073] First, in the charge supply unit (200), a process (S100) is performed to prepare iron-containing materials (M) and coke (C) as charges (M, C) to be charged into the blast furnace (100). That is, multiple hoppers (210) can be prepared. In addition, each of the multiple hoppers (210) can accommodate iron oxide-containing materials and reduced iron-containing materials and coke (C) as the iron-containing materials (M). Specifically, multiple iron oxide hoppers (211) for accommodating iron oxide-containing materials, multiple reduced iron hoppers (212) for accommodating reduced iron-containing materials, and one or multiple coke hoppers (C) for accommodating coke (C) can be prepared.

[0074] The iron oxide-containing material may include sintered ore, sintered ore, and pellets. Accordingly, three or more iron oxide hoppers (211) may be prepared, and each hopper may accommodate different types of iron oxide-containing materials. Of course, the types of iron oxide-containing materials may vary, and accordingly, the number of iron oxide hoppers (211) may vary.

[0075] The reduced iron-containing material may include at least one of pre-reduced scrap, hot briquetted iron (HBI), hot compacted iron (HCI), low reduced iron (LRI), and direct reduced iron (DRI). Hereinafter, an embodiment will be described by exemplifying that the reduced iron-containing material includes hot briquetted iron (HBI). However, the description below may be similarly or identically applied to a case where the reduced iron-containing material includes at least one of pre-reduced scrap, hot briquetted iron (HBI), hot compacted iron (HCI), low reduced iron (LRI), and direct reduced iron (DRI). The reduced iron-containing material may include hot briquetted iron (HBI). Accordingly, one or more reduced iron hoppers (212) may be prepared, and the hot briquetted iron (HBI) may be accommodated in the prepared reduced iron hoppers (212). Of course, the types of reduced iron-containing materials may vary, and accordingly, the number of prepared reduced iron hoppers (212) may also vary, and the prepared reduced iron hoppers (212) may accommodate reduced iron-containing materials by type.

[0076] In addition, by using the charging amount determining unit (300), the charging ratio (M / C) of iron-containing material (M) and coke (C) is determined based on a predetermined standard charging ratio (M S / C S ) is larger than the amount of reduced iron-containing material included in the iron-containing material (M), and a process (S200) is performed to determine the loading amount of iron-containing material (M) and coke (C).

[0077] This process may be performed while preparing the iron-containing material (M) and coke (C), or after preparing the iron-containing material (M) and coke (C). Of course, the process (S200) of determining the loading amount of the iron-containing material (M) and coke (C) may also be performed before preparing the iron-containing material (M) and coke (C).

[0078] In determining the charging amount of iron-containing material (M) and coke (C), the charging ratio of iron-containing material and coke when the iron-containing material (M) contains only iron oxide-containing material is referred to as the standard charging ratio (M). S / C S ) can be determined, and the standard loading ratio (M S / C S ) can be set to be 0.2 to 0.4 greater than the charging ratio (M / C), and the charging amounts of iron-containing material (M) and coke (C) can be set according to the charging ratio (M / C).

[0079] Specifically, the standard loading ratio (M) to be used in the current operation S / C S ), the table stored in the storage of the charging amount determination unit (300) can be output to the selector of the charging amount determination unit (300). At this time, the table is, for example, a data table, and a standard charging ratio (M) determined in advance for each operation history data S / C S ) can have. Here, the standard loading ratio (M S / C S ) refers to the charging ratio of iron oxide-containing material and coke when the iron-containing material (M) contains only iron oxide-containing material. In addition, the standard charging ratio (M) to be used in the current operation S / C S ) refers to the standard charging ratio (M / C) used to determine the charging ratio in the current operation. S / C S ) means.

[0080] Such a table can be derived from the results of previous blast furnace operations using iron-containing materials that do not contain reduced iron. In this case, the iron-containing material that does not contain reduced iron can mean an iron-containing material that does contain iron oxide.

[0081] And, using the selector, the operating condition information of the currently operating load and the operating history data in the data table are used to select multiple standard loading ratios (M) in the data table. S / C S ) among the standard loading ratios (M) to be used in the current operation S / C S ) can be selected. That is, as the operating condition information of the charge currently in operation, the type and quantity of molten iron to be manufactured in the blast furnace operation equipment and the weight information of the charge to be charged into the blast furnace operation equipment in order to manufacture the molten iron in an amount of 1 ton per hour can be selected.

[0082] In addition, among the operation history data on the data table, the operation history data that matches or is closest to the operation condition information of the currently operating loading material can be selected. In addition, multiple standard loading ratios (M) on the data table S / C S ) is the standard loading ratio (M) that matches the selected operation history data. S / C S ) is the standard loading ratio (M) to be used in the current operation S / C S ) can be selected.

[0083] For example, the standard loading ratio (M) in the data table S / C S ) may include 4.6 ratio, 4.8 ratio, 5.0 ratio, 5.2 ratio and 5.4 ratio, and among them, the operation history data on the data table matching the 5.0 ratio may match or be closest to the operation condition information of the currently operating charge. In this case, the reference charge ratio (M) to be used in the current operation S / C S ) can be selected as a ratio of 5.0. Of course, the standard loading ratio (M) exemplified here S / C S ) are examples for explaining the embodiment and are not intended to limit the embodiment.

[0084] Meanwhile, the operating condition information for the currently operating load may have been previously input into the control unit (400). Furthermore, the selector may receive the corresponding information from the control unit (400). Of course, the method by which the selector obtains the operating condition information for the currently operating load may vary.

[0085] Next, using the determiner of the charging amount determination unit (300), the standard charging ratio (M S / C S ) can be determined to be 0.2 to 0.4 greater than the standard charging ratio (M / C). Preferably, using a determination device, the standard charging ratio (M S / C S ) can be determined to be 0.3 to 0.4 greater than the standard charging ratio (M / C). More preferably, using a determinant, the standard charging ratio (M S / C S ) can be determined to be 0.35 to 0.4 greater than the loading ratio (M / C).

[0086] For example, the standard loading ratio (M) to be used in the current operation from the selector to the decision S / C S ) can be entered. In addition, in the decision machine, the standard loading ratio (M) to be used in the current operation S / C S ) can be set to a range of 5.2 to 5.4, which is a numerical range of 0.2 to 0.4 greater than 5.0. Preferably, in the crystallizer, the standard charging ratio (M) to be used in the current operation S / C S ) can be set to a range of 5.3 to 5.4 as the charging ratio (M / C) so that it is 0.3 to 0.4 greater than that. More preferably, in the determination unit, the standard charging ratio (M) to be used in the current operation S / C S ) can be set to a range of 5.35 to 5.4 for a loading ratio (M / C) that is 0.35 to 0.4 greater than the loading ratio (M / C).

[0087] Of course, the standard loading ratio (M) to be used in the current operation from the selector to the decision S / C S ) is entered as a ratio of 4.6, the decision machine uses the standard loading ratio (M) to be used in the current operation. S / C S ) can be set to a range of 4.8 to 5.0, which is 0.2 to 0.4 greater than 4.6, as the loading ratio (M / C).

[0088] At this time, the charging ratio (M / C) determined in proportion to the amount of reduced iron-containing material included in the iron-containing material (M) currently in operation can be modified using a selector. Specifically, the standard charging ratio (M) is determined per 100 kg / tp of the amount of reduced iron-containing material to be included in the iron-containing material (M). S / C S ) can be set to be 0.2 to 0.4 greater than the charging ratio (M / C). That is, if the amount of reduced iron-containing material to be included in the iron-containing material (M) to be used in the current operation is greater than or less than 100 kg / tp, the standard charging ratio (M) to be used in the current operation is set to that ratio. S / C S ) can increase or decrease the value added. Meanwhile, kg / tp, which is a unit expressing the amount of reduced iron-containing material here, can mean the weight of the material used to produce 1 ton of molten iron per unit time.

[0089] For example, when the amount of reduced iron-containing material to be included in the iron-containing material (M) to be used in the current operation is 200 kg / tp, the standard charging ratio (M) to be used in the current operation S / C S ) is 5.0, then the charging ratio (M / C) is the standard charging ratio (M S / C S ) can be modified to a range of 5.4 to 5.8, which is a numerical range of 0.4 to 0.8 greater than 5.0.

[0090] In addition, when the amount of reduced iron-containing material to be included in the iron-containing material (M) to be used in the current operation is 50 kg / tp, the standard charging ratio (M) to be used in the current operation S / C S ) is 5.0, then the charging ratio (M / C) is the standard charging ratio (M S / C S ) can be modified to a range of 5.1 to 5.2, which is a numerical range of 0.1 to 0.2 greater than 5.0.

[0091] Of course, when the amount of reduced iron-containing material to be included in the iron-containing material (M) to be used in the current operation is 100 kg / tp, the standard charging ratio (M) to be used in the current operation S / C S ) is 5.0, then the charging ratio (M / C) is the standard charging ratio (M S / C S ) can be set to a range of 5.2 to 5.4, which is a numerical range of 0.2 to 0.4 greater than 5.0. At this time, the amount of reduced iron-containing material to be included in the iron-containing material (M) to be used in the current operation can be obtained from the operating condition information of the charge currently in operation.

[0092] Next, the charging amount of the iron-containing material (M) and coke (C) can be determined according to the determined or modified charging ratio (M / C) using a determination device. For example, if the amount of the reduced iron-containing material to be used is 100 kg / tp and the determined or modified charging ratio (M / C) is in the range of 5.2 to 5.4, the charging amounts of the iron-containing material (M) and coke (C) can be determined so that the charging amount of the iron-containing material (M) per ton of coke (C) is 5.2 to 5.4 tons. Here, the remainder after excluding 100 kg from the determined charging amount of the iron-containing material (M) can become the charging amount of the iron oxide-containing material. Meanwhile, since the total weight information of the charge to be charged into the blast furnace operation device can be known from the operating condition information of the charge currently in operation, the charging amount of iron-containing material (M) and coke (C) satisfying the charging ratio (M / C) in the range of 5.2 to 5.4 can be determined.

[0093] In this way, the standard loading ratio (M S / C S ) can be set to be 0.2 to 0.4 greater than the charging ratio (M / C), and by setting the charging amounts of iron-containing material (M) and coke (C) according to the charging ratio (M / C), when charging iron-containing material (M) and coke (C) at the set charging amount and blowing hot air to manufacture molten iron, the heat flow rate of the blast furnace can be compensated, and a decrease in ventilation can be prevented or suppressed. Accordingly, during the manufacturing of molten iron, an increase in the furnace temperature at the upper part of the furnace body (110) of the blast furnace (100) can be prevented or suppressed, and a decrease in the gas utilization rate can be prevented or suppressed. In addition, by ensuring sound ventilation of the fusion zone (B3) in the central part of the furnace body (110) of the blast furnace (100), the molten iron can be loaded stably, and accordingly, the molten iron temperature can be raised in the lower part of the furnace body (110) of the blast furnace (100) and the output ratio can be increased.

[0094] In addition, a process (S300) of charging the charge into the blast furnace according to a set charge amount is performed. To this end, the iron oxide-containing material, the reduced iron-containing material, and the coke (C) can be repeatedly discharged sequentially from multiple hoppers according to a predetermined discharge order. In addition, the iron oxide-containing material, the reduced iron-containing material, and the coke (C) can be repeatedly charged into the furnace body (110) of the blast furnace (100) according to the discharge order to form multiple layers, and the position of the reduced iron-containing material can be controlled. At this time, the discharge amount and discharge order of the feeder of the charge supply unit (300) are controlled using the control unit (400), and the conveying speed of the conveyor is controlled, thereby forming multiple layers of the charge in the furnace body (110), and the position of the reduced iron-containing material therein can be controlled.

[0095] Specifically, the control unit (400) can obtain a predetermined discharge order according to the type of the charge from the operating condition information of the charge currently in operation. In addition, the control unit (400) can control the operation of the charge supply unit (300) so that the charge can be charged into the furnace body (110) of the blast furnace (100) according to the determined charge amount and the predetermined discharge order, and the discharge amount and discharge order of each feeder of the charge supply unit (300) can be controlled. Accordingly, the iron oxide-containing material, the reduced iron-containing material, and the coke (C) can be discharged to the conveyor (220) according to the determined charge amount and the predetermined discharge order, and can be transported to the furnace top hopper (130) and charged into the furnace body (110) of the blast furnace (100) by the operation of the distribution chute (140). At this time, in repeatedly discharging sequentially from a plurality of hoppers, the reduced iron-containing material can be discharged before the iron oxide-containing material.

[0096] In addition, in controlling the position of the reduced iron-containing material, the radial position (R) of the reduced iron-containing material can be controlled so that the reduced iron-containing material is concentrated in the inner wall region (D1) among the inner wall region (D1) and the central region (D2) of the blast furnace throughout the multiple layers (A). Specifically, 65% of the total charge of the reduced iron-containing material can be concentrated in a region from 100% to 70% of the blast furnace radius from the inner wall to the center of the furnace body (110) of the blast furnace (100). Alternatively, 35% of the total charge of the reduced iron-containing material can be concentrated in a region from 100% to 80% of the blast furnace radius from the inner wall to the center of the furnace body (110) of the blast furnace (100). Here, the 100% position of the blast furnace radius can be the blast furnace inner wall position, the 0% position of the blast furnace radius can be the blast furnace center position, and the larger the number, the closer it can be to the blast furnace inner wall. Meanwhile, the inner wall of the blast furnace may refer to the inner wall of the furnace body (110) of the blast furnace (100). Similarly, the center of the blast furnace may refer to the center of the furnace body (110) of the blast furnace (100).

[0097] In this way, when charging the material into the furnace body (110) of the blast furnace (100), the operation efficiency and stability of the blast furnace operation can be secured by charging the material containing reduced iron so that it is concentrated in the inner wall area (D1) of the blast furnace.

[0098] This charging method takes into consideration the reduction characteristics of iron oxide-containing materials. For example, by charging the reduced iron-containing material so that it is concentrated in the inner wall region (D1) of the blast furnace, the reduced iron-containing material can be concentrated in the inner wall region (D1) of the blast furnace where the concentration of gas, for example, the reducing gas, is relatively low, and the iron oxide-containing material with high reducibility can be positioned in the central region (D2) of the blast furnace where the concentration of the reducing gas is relatively high. Accordingly, the utilization efficiency of the reducing gas in the central region (D2) of the blast furnace can be increased. That is, since the reduced iron-containing material has already been reduced, the gas utilization rate in the blast furnace operation may decrease as much as the reduced iron-containing material is used as a charge. To prevent this, by concentrating the reduced iron-containing material in the inner wall region (D1) of the blast furnace, the decrease in the gas utilization rate can be minimized, and accordingly, the effect of reducing the conversion cost can be increased when charging the reduced iron-containing material.

[0099] In addition, by charging the reduced iron-containing material so that it is concentrated in the inner wall region (D1) of the blast furnace, the shape of the fusion zone (B3) can be stably formed and maintained in an inverted 'V' shape. This allows for a stable central gas flow within the blast furnace, thereby improving gas flow distribution. In addition, by suppressing the development of wall currents, heat loss to the inner wall of the furnace body (110) can be reduced, and wear of the furnace body (110) can be minimized.

[0100] Specifically, in blast furnace operation, the shape of the fusion zone (B3) plays a significant role in determining the height within the blast furnace where the charge reaches temperatures of, for example, 1300°C or higher in the radial direction (R). Furthermore, since the reduced iron-containing material has a dense structure both on the surface and inside, the rate of heat transfer from the reducing gas to the reduced iron-containing material is very slow.

[0101] Therefore, in the inner wall region (D1) of the blast furnace where the reduced iron-containing material is charged, the temperature of the charge rises at a slower rate than in other regions. Therefore, the temperature of the charge can be made relatively low at the same location inside the blast furnace where the reduced iron-containing material is charged. That is, in the inner wall region (D1) of the blast furnace where a large amount of reduced iron-containing material is charged, the height at which the charge reaches 1300℃ or higher becomes low. However, in the central region (D2) of the blast furnace where the reduced iron-containing material is not charged primarily, the temperature is maintained relatively high compared to the inner wall region (D1) of the blast furnace, and therefore, due to this temperature difference, the shape of the fusion zone (B3) can be induced to have an inverted 'V' shape.

[0102] In addition, in controlling the position of the reduced iron-containing material, the vertical position of the reduced iron-containing material can be controlled so that the reduced iron-containing material is concentrated below the iron oxide-containing material in each layer. In this way, when charging the charge into the furnace body (110) of the blast furnace (100), by charging the reduced iron-containing material so that it is concentrated below the iron oxide-containing material, the operational efficiency and stability of the blast furnace operation can be further secured.

[0103] That is, the melting temperatures of the reduced iron-containing material and the iron oxide-containing material are different. For example, the reduced iron-containing material may melt at a higher temperature than the iron oxide-containing material. In addition, heat may be transferred from the bottom to the top inside the furnace body (110) of the blast furnace (100). Accordingly, if the reduced iron-containing material is loaded so that it is concentrated below the iron oxide-containing material, the iron oxide-containing material, which melts relatively quickly, may melt first and be dropped, while the reduced iron-containing material located below it may begin to melt, and accordingly, the melt of the iron oxide-containing material and the melt of the reduced iron-containing material may be mixed. From this, the assimilation characteristics of the reduced iron-containing material can be improved.

[0104] In addition, while charging the charge into the blast furnace according to the set charge amount, a process (S400) for manufacturing molten iron (L) from the charge (M, C) is performed. For example, hot air can be blown into the inside of the furnace body (110) of the blast furnace (100) through the tuyere (120) to burn coke, and the combustion heat and combustion gas generated by the combustion can be used to melt the iron oxide-containing material. That is, the combustion heat and combustion gas generated by burning coke can be moved from the bottom to the top of the furnace body (110) of the blast furnace (100) and brought into contact with the iron oxide-containing material to melt the iron oxide-containing material. At this time, the iron oxide-containing material can be melted first, and the molten material thus generated can be dropped onto the iron oxide-containing material located below it. In addition, the combustion heat and combustion gas generated by burning coke can be used to melt the reduced iron-containing material. Accordingly, the molten iron oxide-containing material and the molten iron-containing material can be mixed, thereby improving the assimilation properties of the reduced iron-containing material. In addition, the mixed molten iron can be dropped onto the lower side of the furnace body (110) of the blast furnace (100). Through this process, a layer of molten iron (L) and molten slag can be formed on the inner bottom of the furnace body (110). The molten iron (L) can be discharged into the large hot water tank through an outlet formed at the lower part of the furnace body (110).

[0105] FIG. 4 is a drawing for illustrating the effect of the vertical position of charging a reduced iron-containing material in a blast furnace operation according to an embodiment of the present invention, in comparison with a comparative example. In addition, FIG. 5 is a drawing for explaining the effect of the vertical position of charging a reduced iron-containing material in a blast furnace operation according to an embodiment of the present invention, in comparison with a comparative example.

[0106] Referring to FIGS. 4 and 5, a second method of charging a reduced iron-containing material under an iron oxide-containing material in a blast furnace operation according to an embodiment of the present invention is described.

[0107] Fig. 4 (a) is a drawing visualizing the behavior of the molten material in the test vessel being dropped using X-ray while simulating the blast furnace operation in a test vessel by preparing sintered ore, pellets, and sintered ore as iron oxide-containing materials in a predetermined test vessel for simulating the blast furnace operation, and preparing high-temperature briquette iron (HBI) as a reduced iron-containing material underneath, and then injecting reducing gas having a temperature of about 1500℃, specifically 1508℃, into the bottom of the test vessel and discharging it through the top. In Fig. 4 (a), the HBI layer refers to the layer in which the high-temperature briquette iron (HBI) is melted, and the ore layer refers to the layer in which the iron oxide-containing material is melted. Meanwhile, Fig. 5 (a) is a drawing schematically showing Fig. 4 (a).

[0108] In addition, (b) of Fig. 4 is a drawing visualizing the behavior of the molten material in the test vessel being dropped using X-ray while simulating the blast furnace operation in a test vessel by preparing high-temperature briquette iron (HBI) as a reduced iron-containing material in a predetermined test vessel for simulating the blast furnace operation, and preparing sintered ore, pellets, and sintered ore as iron oxide-containing materials underneath, and then injecting reducing gas having a temperature of about 1500℃, specifically 1495℃, into the bottom of the test vessel and discharging it through the top. In Fig. 4 (b), the ore layer refers to a layer in which the iron oxide-containing material is melted, and the HBI layer refers to a layer in which the high-temperature briquette iron (HBI) is melted. Meanwhile, Fig. 5 (b) is a drawing schematically showing (b) of Fig. 4.

[0109] Looking at Fig. 4 (a) and Fig. 5 (a), when the reduced iron-containing material is loaded into the upper part of the test vessel, the iron oxide-containing material at the lower part is melted first and dropped before the reduced iron-containing material at the upper part is melted, so it can be confirmed that the molten layer of the reduced iron-containing material and the molten layer of the iron oxide-containing material are separated.

[0110] However, as shown in (b) of Fig. 4 and (b) of Fig. 5, when the reduced iron-containing material is loaded into the lower part of the test vessel, the iron oxide-containing material at the upper part is melted first and dripped onto the reduced iron-containing material at the lower part before the reduced iron-containing material at the lower part is melted, so it can be seen that the molten layer of the iron oxide-containing material and the molten layer of the reduced iron-containing material are well mixed.

[0111] Therefore, according to an embodiment of the present invention, it can be seen that the assimilation of the reduced iron-containing material can be improved by loading the reduced iron-containing material under the iron oxide-containing material.

[0112] FIG. 6 is a drawing for exemplifying the relationship between the discharge order of iron oxide-containing material, reduced iron-containing material, and coke and the vertical position of the reduced iron-containing material in a blast furnace operation according to an embodiment of the present invention. In addition, FIG. 7 is a drawing for exemplifying the relationship between the discharge order of iron oxide-containing material, reduced iron-containing material, and coke and the radial position of the reduced iron-containing material in a blast furnace operation according to an embodiment of the present invention.

[0113] Hereinafter, in order to control the vertical and radial positions of the reduced iron-containing material within the furnace (110) in an embodiment of the present invention, the reason for discharging the reduced iron-containing material in advance of the iron oxide-containing material when sequentially and repeatedly discharging from multiple hoppers will be explained with reference to FIGS. 6 and 7.

[0114] As explained above, when charging a charge, the radial (R) position of the reduced iron-containing material is controlled so that the reduced iron-containing material is concentrated in the inner wall area (D1) of the blast furnace over the entire multiple layers (A) within the furnace body (110), and the vertical position of the reduced iron-containing material is controlled so that the reduced iron-containing material is concentrated in the lower part of the iron oxide-containing material in each layer, thereby ensuring operational stability and improving operational efficiency in blast furnace operation.

[0115] Therefore, to derive a method for positioning reduced iron-containing materials at the appropriate locations, a simulation of the charge flow, mixing, and segregation behaviors of the blast furnace charging system was performed. The model used in this simulation fully simulates the charge's dropping behavior from the blast furnace storage tank to the relay tank, furnace top hopper, distribution chute, and the blast furnace interior. By conducting simulations using this model, the charge distribution within the blast furnace can be accurately confirmed.

[0116] The distribution of reduced iron-containing materials derived from the simulation, specifically, the distribution of reduced iron-containing materials in each of the multiple layers of the charge formed in the blast furnace when the reduced iron-containing materials were discharged in advance, in the middle, and afterward through the simulation, are shown in Fig. 6 (a) to (c). Here, M1 refers to the reduced iron-containing material, M2a refers to the iron oxide-containing material (large particles), M2b refers to the iron oxide-containing material (small particles), and C refers to coke. In addition, discharging the reduced iron-containing material in advance means that the reduced iron-containing material is discharged from the hopper containing the reduced iron-containing material before discharging the iron oxide-containing material from the hopper containing the iron oxide-containing material (large and small particles). In addition, discharging the reduced iron-containing material afterward means that the reduced iron-containing material is discharged from the hopper containing the reduced iron-containing material after discharging the iron oxide-containing material from the hopper containing the iron oxide-containing material (large and small particles). And, intermediate discharge of reduced iron-containing material means that while discharge of iron oxide-containing material from a hopper containing iron oxide-containing material (large and small particles) is taking place, reduced iron-containing material is discharged from a hopper containing reduced iron-containing material.

[0117] Referring to Figure 6, it can be seen that when the reduced iron-containing material is discharged first and then second, more reduced iron-containing material is distributed at the bottom of each layer of the charge compared to when the reduced iron-containing material is discharged in the middle order.

[0118] In addition, the distribution of reduced iron-containing material in the radial direction across multiple layers of the charge formed in the blast furnace when the reduced iron-containing material was discharged in the preceding, middle, and following stages, as derived from the simulation, is shown in Fig. 7. Here, the mass ratio refers to the mass of the reduced iron-containing material relative to the mass of the entire charge at that location.

[0119] In Fig. 7, the horizontal axis represents the radial position from the center of the blast furnace to the inner wall of the blast furnace, with the center of the blast furnace set to 0 and the inner wall of the blast furnace set to 4, and the vertical axis represents the amount of reduced iron-containing material in the charge when the amount of charge is set to 1. As shown in Fig. 7, it was confirmed that when the reduced iron-containing material was discharged in advance, a relatively larger amount of reduced iron-containing material was charged toward the inner wall of the blast furnace.

[0120] Therefore, when using a reduced iron-containing material in a blast furnace, if the discharge pattern is conducted in advance so that the reduced iron-containing material is discharged from the hopper before the iron oxide-containing material, the charging position in the blast furnace can be guided to near the inner wall of the blast furnace and to the bottom of the layer of the iron oxide-containing material, and in this case, as described above, the operational efficiency and stability of the blast furnace operation can be improved.

[0121] Hereinafter, referring to FIGS. 8 and 9, the charging ratio (M / C) per standard charging amount (100 kg / tp) of the reduced iron-containing material according to an embodiment of the present invention is expressed as the standard charging ratio (M S / C S ) is determined to be 0.2 to 0.4 greater than the reference value.

[0122] FIG. 8 is a diagram illustrating a decrease in heat flow ratio according to the amount of reduced iron-containing material charged in a blast furnace operation according to an embodiment of the present invention. In addition, FIG. 9 is a diagram illustrating a change in differential pressure within a blast furnace according to the presence or absence of reduced iron-containing material charged in a blast furnace operation according to an embodiment of the present invention.

[0123] When an iron-containing material (M) including a reduced iron-containing material and an iron oxide-containing material is charged into a furnace body (110) of a blast furnace (100) during blast furnace operation, the reduced iron-containing material causes the furnace top temperature to rise, the gas utilization rate to fall, the ventilation rate to improve, and the molten iron temperature to rise. Here, the effects of the increased furnace top temperature and the decreased gas utilization rate may have a negative impact on blast furnace operation. On the other hand, the effects of the improved ventilation rate and the increased molten iron temperature may improve the operational efficiency of blast furnace operation.

[0124] At this time, as in the embodiment of the present invention, the charging ratio (M / C) of the iron-containing material (M) and coke (C) charged into the furnace body (110) of the blast furnace (100) is the standard charging ratio (M S / C S ) is adjusted upward, the furnace temperature in the furnace body (110) of the blast furnace (100) can be lowered, the gas utilization rate can be increased, the ventilation can be improved, and the molten iron temperature can be increased. Furthermore, the charging ratio (M / C) can be optimized by modifying the charging ratio (M / C) according to the amount of the reduced iron-containing material to be charged into the furnace body (110) of the blast furnace (100) in order to manufacture 1 ton of molten iron per unit time in the blast furnace (100). In addition, by optimizing the charging ratio (M / C) in this way, the effect of reducing the reducing agent cost due to charging the reduced iron-containing material into the furnace body (110) of the blast furnace (100) can be further improved.

[0125] Accordingly, the impact of the increase in the charging ratio (M / C) on the blast furnace operation can be analyzed, and the optimal upward charging ratio (M / C) can be derived from the analysis results.

[0126] First, the heat flow rate in the furnace operation can be expressed by the following equation.

[0127] [Heat flow ratio formula] W s / W g = (C s ·G s ) / (C g ·G g )

[0128] Here, W s refers to the heat capacity of the solid (i.e., the charge), and W g means the heat capacity of the gas (i.e., the core gas). Also, C s is the specific heat of the solid (㎉ / ㎏℃), and G s is the mass flow rate of the solid (㎏ / Hr), and C g is the specific heat of the gas (㎉ / N㎥℃), and G g is the volume flow rate of gas at 1 atm (N㎥ / Hr).

[0129] In blast furnace operation, the heat flow ratio can be used as an indicator of heat exchange in the central portion of the furnace body (110) of the blast furnace (100), such as the shaft portion. For example, if the heat flow ratio is low, the temperature of the furnace gas may rise, and the thermal efficiency may decrease. Meanwhile, the specific heat of a reduced iron-containing material is half that of an iron oxide-containing material. Therefore, if a blast furnace is operated by charging a reduced iron-containing material instead of an iron oxide-containing material, the heat flow ratio may decrease.

[0130] FIG. 8 is a drawing for exemplifying a decrease in heat flow ratio according to the amount of reduced iron-containing material charged in a blast furnace operation according to an embodiment of the present invention.

[0131] Figure 8 is a diagram showing the decrease in heat flow ratio when the charge amount (kg / tp) of a reduced iron-containing material is changed from 0 to 200 in a blast furnace operation with a charge ratio (M / C) of 5.0, 5.2, 5.4, and 5.6, respectively. Here, the charge amount (kg / tp) means the charge amount of a reduced iron-containing material for producing 1 ton of molten iron per unit time.

[0132] As shown in Fig. 8, it can be seen that in blast furnace operation using reduced iron-containing materials, if the charging ratio (M / C) per 100 kg / tp of reduced iron-containing materials is increased by 0.2 or more, the heat flow rate can be compensated.

[0133] That is, when comparing the heat flow ratio when the charge amount of reduced iron-containing material is 0 kg / tp in blast furnace operation with a charge ratio (M / C) of 5.0, the heat flow ratio when the charge amount of reduced iron-containing material is 100 kg / tp in blast furnace operation with a charge ratio (M / C) of 5.0, and the heat flow ratio when the charge amount of reduced iron-containing material is 100 kg / tp in blast furnace operation with a charge ratio (M / C) of 5.2, it can be seen that when the charge amount of reduced iron-containing material is increased from 0 to 100 kg / tp and the charge ratio (M / C) is increased from 5.0 to 5.2, the heat flow ratio is compensated. In addition, when the loading amount of reduced iron-containing material is increased from 0 to 200 kg / tp, it can be seen that the heat flow rate is compensated when the loading ratio (M / C) is increased from 5.0 to 5.4. In other words, it can be seen that the heat flow rate can be compensated when the loading ratio (M / C) is increased by 0.2 or more per 100 kg / tp of reduced iron-containing material loaded.

[0134] That is, the decrease in heat flow ratio due to the charging of reduced iron-containing materials can be compensated for by increasing the charging ratio (M / C) of iron-containing materials (M) and course (C) including reduced iron-containing materials and iron oxide-containing materials to 0.2 or more. By compensating for the heat flow ratio, it is possible to prevent a decrease in thermal efficiency when charging reduced iron-containing materials and to prevent the furnace temperature from rising. In other words, it is possible to optimize the thermal efficiency in blast furnace operation and increase the efficiency of using reduced iron-containing materials.

[0135] Meanwhile, among the effects that can be obtained by charging an iron-containing material (M) including a reduced iron-containing material and an iron oxide-containing material into the furnace body (110) of a blast furnace (100) during blast furnace operation, the effect of improved ventilation is an effect that occurs due to the lower content of gangue of the reduced iron-containing material compared to the iron oxide-containing material and the amount of the iron oxide-containing material that is reduced as much as the reduced iron-containing material is used. That is, by charging a reduced iron-containing material into the furnace body (110) of the blast furnace (100) during blast furnace operation, the amount of slag generated in the middle and lower portions of the furnace body (110) of the blast furnace (100) is reduced, so that the ventilation in the middle and lower portions of the furnace body (110) of the blast furnace (100) is improved.

[0136] However, when the charging ratio (M / C) is increased to compensate for the heat flow ratio, the amount of iron oxide-containing material among the iron-containing materials becomes greater than that of coke. At this time, the porosity of the iron oxide-containing material is lower than that of coke, and the softening and melting caused by the iron oxide-containing material hinders the gas flow, which may reduce the air permeability of the central and lower portions of the furnace body (110) of the blast furnace (100). Therefore, by controlling the degree to which the charging ratio (M / C) is increased to compensate for the heat flow ratio, the air permeability can be prevented from decreasing.

[0137] Fig. 9 is a diagram showing the pressure drop inside the blast furnace when the charge ratio (M / C) is changed from 4.6 to 5.4 in a blast furnace operation in which the charge amount of a reduced iron-containing material, for example, high-temperature briquette iron (HBI), is 0%, for example, 0 kg / tp, relative to 100% of the total charge amount of the charge, and in which the charge amount of a reduced iron-containing material, for example, high-temperature briquette iron (HBI), is 5%, for example, 100 kg / tp, relative to 100% of the total charge amount of the charge. At this time, a larger magnitude of the pressure drop means worse permeability. In the graph, the horizontal axis represents the charge ratio (M / C), and the vertical axis represents the magnitude of the pressure drop per 1 L of gas flowing from the bottom to the top of the blast furnace.

[0138] For example, an experiment is conducted to evaluate the softening and melting characteristics of iron-containing materials in the charge using the operating conditions of a blast furnace with a charge of 0 kg / tp of reduced iron-containing materials and the operating conditions of a blast furnace with a charge of 100 kg / tp of reduced iron-containing materials. Then, from the softening and melting characteristic evaluation experiment, the results of the change in differential pressure in the blast furnace, that is, the pressure drop while gas flows from the bottom to the top of the blast furnace, are simulated and presented. Then, from the derived results, the differential pressure occurring in the 1400℃ region inside the blast furnace is diagrammed and presented in a drawing.

[0139] As shown in Fig. 9, when comparing the pressure drop graph in the blast furnace operation with the charge of 100 kg / tp of reduced iron-containing material derived from the softening melting characteristic evaluation experiment and the pressure drop graph in the blast furnace operation with the charge of 0 kg / tp of reduced iron-containing material, it can be seen that the pressure drop due to differential pressure can be compensated for when the charge ratio (M / C) per 100 kg / tp of reduced iron-containing material is increased to the level of 0.4. In addition, when the charge ratio (M / C) per 100 kg / tp of reduced iron-containing material is increased to greater than 0.4, the pressure drop cannot be compensated for, resulting in poor ventilation. From this, it was confirmed through experiments and simulations that even when the charge ratio (M / C) per 100 kg / tp of reduced iron-containing material is increased to 0.4 or less, no deterioration in furnace ventilation will occur.

[0140] Therefore, as in the embodiment of the present invention, from the two viewpoints of compensation for heat flow ratio and prevention of reduction in air permeability, it can be seen that by increasing the loading ratio (M / C) per 100 kg / tp of reduced iron-containing material to 0.2 or more and 0.4 or less, the heat flow ratio can be compensated for while preventing reduction in air permeability.

[0141] In addition, if the blast furnace charging ratio (M / C) is adjusted upward within this range, the ratio of the mass of iron oxide-containing material, e.g., iron ore, to the total amount of gas, e.g., reducing gas (carbon monoxide gas) increases, so the ratio of gas used for the reduction of iron oxide-containing material can increase, which leads to an increase in the gas utilization rate of the blast furnace.

[0142] Furthermore, it is known that when a material containing reduced iron is charged into a blast furnace, the direct reduction reaction, which is an endothermic reaction at the bottom of the blast furnace body, is reduced, while an increase in the charging ratio (M / C) inside the blast furnace is known to affect a decrease in the molten iron temperature.

[0143] Therefore, it can be seen that increasing the charging ratio (M / C) along with the charging of reduced iron-containing materials is mutually complementary in terms of permeability, heat flow rate, and molten iron temperature.

[0144] Therefore, according to an embodiment of the present invention in which the charging ratio (M / C) of a reduced iron-containing material is increased to an appropriate level, the ventilation inside the blast furnace body can be maintained as is, while the rise in the furnace temperature can be suppressed, the gas utilization rate inside the blast furnace can be increased, and the temperature of the molten iron produced in the blast furnace can be suppressed, thereby maximizing the effect of reducing the reducing agent ratio when the reduced iron-containing material is used in the blast furnace.

[0145] According to an embodiment of the present invention, a predetermined standard loading ratio (M S / C S ) and the amount of reduced iron-containing material included in the iron-containing material (M), the charging ratio (M / C) of the iron-containing material (M) and the coke (C) is determined, and specifically, the charging ratio (M / C) of the iron-containing material (M) and the coke (C) is determined in advance. S / C S ) is determined in proportion to the amount of the reduced iron-containing material, and the charging ratio (M / C) can be determined from this. Accordingly, when the reduced iron-containing material is used in blast furnace operation, the furnace temperature can be prevented or suppressed from rising, and the gas utilization rate can also be prevented or suppressed from falling. In addition, the permeability can be improved by thinning the fusion zone, and the molten iron temperature can be increased. Accordingly, the effect of reducing the reducing agent ratio can be increased, and the stability of operation can be secured.

[0146] Furthermore, according to an embodiment of the present invention, by controlling the discharge order according to the type of charge, the radial position and vertical position of the reduced iron-containing material in the layer of the charge can be controlled to an optimal position, thereby improving the gas utilization rate, stabilizing the temperature and gas temperature distribution within the furnace body, improving the effect of reducing the reducing agent ratio, and ensuring operational stability. Accordingly, by reducing the reducing agent ratio and ensuring operational stability, it can contribute to reducing the amount of carbon dioxide generated in the blast furnace.

[0147] The above embodiments of the present invention are intended to illustrate 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 with each other and combined and modified in various forms, and that such modifications may also be considered within the scope of the present invention. In other words, the present invention may be implemented in various different forms within the scope of the claims and equivalent technical concepts thereof, and those skilled in the art will understand that various embodiments are possible within the scope of the technical concepts of the present invention.

[0148] (Explanation of symbols)

[0149] 100: furnace, 200: charge supply section, 300: charge amount determination section, 400: control section, 500: hot air supply section.

Claims

1. A process of preparing iron-containing material (M) and coke (C) as materials to be charged into a blast furnace; The charging ratio (M / C) of the above iron-containing material (M) and the above coke (C) is a predetermined standard charging ratio (M S / C S ) and a process of determining the loading amount of the iron-containing material (M) and coke (C) according to the amount of reduced iron-containing material included in the iron-containing material (M); The process of charging the above-mentioned material into the blast furnace according to the set charging amount; and A blast furnace operating method comprising a process for manufacturing molten iron from the above-mentioned charge.

2. In claim 1, The process of preparing the above iron-containing material (M) and coke (C) is as follows: The process of preparing multiple hoppers; and A blast furnace operating method comprising: a process of receiving an iron oxide-containing material and a reduced iron-containing material as the iron-containing material (M) and the coke (C) in each of the above-described hoppers; 3. In claim 2, A blast furnace operating method, wherein the reduced iron-containing material comprises at least one of pre-reduced scrap, hot briquetted iron (HBI), hot compacted iron (HCI), low reduced iron (LRI), and direct reduced iron (DRI).

4. In any one of claims 1 to 3, The process of determining the loading amount of the above iron-containing material (M) and coke (C) is as follows: In the case where the above iron-containing material (M) contains only iron oxide-containing material, the charging ratio of iron oxide-containing material and coke is the standard charging ratio (M S / C S ) and the process of determining The above standard loading ratio (M S / C S ) to be 0.2 to 0.4 greater than the above charging ratio (M / C); A blast furnace operating method, comprising: a process for determining the charging amount of the iron-containing material (M) and coke (C) according to the charging ratio (M / C).

5. In claim 4, The process of determining the above charging ratio (M / C) is as follows: A blast furnace operating method comprising: a process of modifying the charging ratio (M / C) in proportion to the amount of reduced iron-containing material included in the iron-containing material (M).

6. In claim 2 or claim 3, The process of charging the above-mentioned material into the above-mentioned blast furnace is as follows: A process of sequentially and repeatedly discharging the above iron oxide-containing material, the above reduced iron-containing material, and the above coke (C) from the plurality of hoppers according to a predetermined discharge order; and A blast furnace operating method comprising: a process of repeatedly charging the iron oxide-containing material, the reduced iron-containing material, and the coke (C) into the blast furnace in the order of discharge to form multiple layers, and controlling the position of the reduced iron-containing material.

7. In claim 6, The process of sequentially discharging from the above multiple hoppers is: A blast furnace operating method comprising a process of discharging the reduced iron-containing material before the iron oxide-containing material.

8. In claim 6, The process of controlling the position of the above reduced iron-containing material is: A process of controlling the radial position of the reduced iron-containing material so that the reduced iron-containing material is concentrated in the inner wall region among the inner wall region and the central region of the blast furnace over the entire multiple layers; and A blast furnace operating method comprising: a process of controlling the vertical position of the reduced iron-containing material so that the reduced iron-containing material is concentrated below the iron oxide-containing material in each layer; 9. In claim 8, The process of controlling the left and right positions of the above reduced iron-containing material is as follows: A blast furnace operating method comprising: a process of distributing 65% of the total charge of the reduced iron-containing material to an area of ​​100% to 70% of the radius of the blast furnace from the inner wall to the center of the blast furnace.

10. In claim 8, The process of manufacturing the above-mentioned ship is as follows: A process of burning the coke by blowing hot air into the inside of the blast furnace; A process of melting the iron oxide-containing material using combustion heat and combustion gas; and A blast furnace operating method comprising a process of melting the reduced iron-containing material using combustion heat and combustion gas.

11. Therefore; A charge supply unit installed to charge iron-containing material (M) and coke (C) as charge into the blast furnace; The charging ratio (M / C) of the above iron-containing material (M) and the above coke (C) is a predetermined standard charging ratio (M S / C S ) and a charging amount determining unit for determining the charging amount of the iron-containing material (M) and coke (C) according to the amount of reduced iron-containing material included in the iron-containing material (M); and A blast furnace operating device including a control unit that controls the operation of the charge supply unit so that the charge can be charged into the blast furnace according to the charge amount determined by the charge amount determination unit.

12. In claim 11, The above-mentioned material supply unit is, A plurality of hoppers formed so that the iron oxide-containing material, the reduced iron-containing material, and the coke (C) as the iron-containing material (M) can be stored and discharged therein, respectively; A feeder installed in each of the above multiple hoppers and having its opening and closing operation controlled by the control unit; and A blast furnace operating device including a conveyor installed to connect the above-described multiple hoppers and the blast furnace, the conveying operation of which is controlled by the control unit.

13. In claim 11, The above charging amount determining unit is, Pre-determined standard loading ratio (M) for each operation history data S / C S ) storage where the table is stored; Using the operating condition information and the operation history data of the currently operating loading material, multiple standard loading ratios (M) are established. S / C S ) among the standard loading ratios (M) to be used in the current operation S / C S ) selector; and The above standard loading ratio (M S / C S ) to be 0.2 to 0.4 greater than the charging ratio (M / C), and a determining device for determining the charging amount of the iron-containing material (M) and coke (C) according to the charging ratio (M / C); A blast furnace operating device comprising:

14. In claim 13, The above-mentioned determination device is a blast furnace operation device that modifies the charging ratio (M / C) determined in proportion to the amount of reduced iron-containing material included in the iron-containing material (M) currently in operation.

15. In claim 13 or claim 14, The above standard loading ratio (M S / C S ) is a blast furnace operation device in which the charging ratio of iron oxide-containing material and coke is when the iron-containing material (M) contains only iron oxide-containing material.

16. In claim 12, The above control unit controls the discharge amount of each feeder so that the charge can be charged into the blast furnace according to the determined charge amount, and controls the operating order of each feeder and the conveying speed of the conveyor so that the left-right position and the up-down position of the reduced iron-containing material inside the blast furnace can be controlled. A blast furnace operating device.

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