Hydrogen production device and iron-making equipment equipped with this hydrogen production device

Abstract

A hydrogen production device capable of efficiently producing hydrogen used in a hydrogen reduction ironmaking process and an ironmaking apparatus equipped with the hydrogen production device are provided. [Solution] The hydrogen production device includes a reduction furnace that reduces iron ore with a hydrogen-containing gas containing hydrogen, a reactor that directly decomposes hydrocarbons by bringing a hydrocarbon-containing gas containing hydrocarbons into contact with a catalyst that is at least a portion of the sponge iron obtained by reducing the iron ore in the reduction furnace, and a hydrogen-containing gas line for supplying at least a portion of the reaction gas flowing out of the reactor to the reduction furnace as at least a portion of the hydrogen-containing gas.

Description

[Technical Field]

[0001] The present disclosure relates to a hydrogen production device and an iron-making apparatus equipped with the hydrogen production device. [Background technology]

[0002] The hydrogen reduction ironmaking process is known as one solution for achieving decarbonization in the steelmaking process. In order to minimize carbon dioxide emissions, it is necessary to produce the hydrogen used in the hydrogen reduction ironmaking process using a method that produces minimal carbon dioxide emissions. One example of such a method for producing hydrogen is the direct decomposition of hydrocarbons described in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7089235 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when combining the hydrogen reduction ironmaking process with the direct hydrocarbon cracking process, if commercial-grade iron produced by the hydrogen reduction ironmaking process (low-porosity iron that has been melted to remove impurities, etc.) is used as a catalyst for the direct hydrocarbon cracking process, it is expected that a certain amount of time will be required for the activity of the direct hydrocarbon cracking reaction to become active.To commercialize the combination of the hydrogen reduction ironmaking process and the direct hydrocarbon cracking process, a catalyst with high hydrogen production efficiency that becomes active in a shorter time is desired.

[0005] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a hydrogen production device that can efficiently produce hydrogen to be used in a hydrogen reduction ironmaking process, and an ironmaking apparatus equipped with this hydrogen production device. [Means for solving the problem]

[0006] In order to achieve the above object, the hydrogen production apparatus according to the present disclosure includes a reduction furnace that reduces iron ore with a hydrogen-containing gas containing hydrogen, a reactor that directly decomposes hydrocarbons by bringing a hydrocarbon-containing gas containing hydrocarbons into contact with a catalyst that is at least a portion of the sponge iron obtained by reducing the iron ore in the reduction furnace, and a hydrogen-containing gas line for supplying at least a portion of the reaction gas flowing out of the reactor to the reduction furnace as at least a portion of the hydrogen-containing gas. [Effects of the Invention]

[0007] The hydrogen production device disclosed herein produces hydrogen by the direct decomposition of hydrocarbons using sponge iron, obtained by reducing iron ore with hydrogen, as a catalyst. Because sponge iron is highly porous, the activation of the direct decomposition reaction of hydrocarbons increases more quickly than with commercial-grade iron. This allows for efficient production of hydrogen for use in the hydrogen reduction ironmaking process. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a configuration block diagram of a hydrogen production device according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a configuration block diagram of a modified example of the hydrogen production device according to the first embodiment of the present disclosure. [Figure 3] FIG. 4 is a configuration block diagram of another modified example of the hydrogen production device according to the first embodiment of the present disclosure. [Figure 4] FIG. 10 is a configuration block diagram of yet another modified example of the hydrogen production device according to the first embodiment of the present disclosure. [Figure 5] FIG. 10 is a configuration block diagram of a hydrogen production device according to a second embodiment of the present disclosure. [Figure 6] FIG. 10 is a configuration block diagram of a modified example of the hydrogen production device according to the second embodiment of the present disclosure. [Figure 7] FIG. 10 is a configuration block diagram of yet another modified example of the hydrogen production device according to the first embodiment of the present disclosure. [Figure 8]FIG. 10 is a configuration block diagram of another modified example of the hydrogen production device according to the second embodiment of the present disclosure. [Figure 9] 1 is a block diagram of a configuration of an iron-making apparatus equipped with a hydrogen production apparatus according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a hydrogen production device according to an embodiment of the present disclosure will be described with reference to the drawings. The embodiment described below shows one aspect of the present disclosure, and is not intended to limit the present disclosure. The embodiment can be modified as desired within the scope of the technical concept of the present disclosure.

[0010] [Hydrogen production equipment] (Embodiment 1) <Configuration of the hydrogen production device according to the first embodiment of the present disclosure> As shown in FIG. 1 , the hydrogen production apparatus 1 according to the first embodiment of the present disclosure includes a reduction furnace 2 that reduces iron ore with a hydrogen-containing gas containing hydrogen, a reactor 3 that directly decomposes hydrocarbons using sponge iron obtained by reducing the iron ore in the reduction furnace 2 as a catalyst, and a hydrogen-containing gas line 4 that supplies the reaction gas flowing out of the reactor 3 as a hydrogen-containing gas to the reduction furnace 2. The hydrogen-containing gas is not limited to being composed only of hydrogen, and may contain components other than hydrogen, such as inert gases such as nitrogen and rare gases. Furthermore, the hydrocarbons contained in the hydrocarbon-containing gas may be saturated hydrocarbons such as methane and ethane, unsaturated hydrocarbons such as ethylene and acetylene, or mixtures thereof. Furthermore, the hydrocarbon-containing gas is not limited to being composed only of such hydrocarbons, and may also contain the above-mentioned inert gases, hydrogen, etc.

[0011] An iron ore line 5 for supplying iron ore to the reduction furnace 2 may be connected to the reduction furnace 2. In addition, in order to transfer sponge iron from the reduction furnace 2 to the reactor 3, the reduction furnace 2 and the reactor 3 may be communicated with each other through a sponge iron line 6. Furthermore, in order to supply a hydrocarbon-containing gas line 7 to the reactor 3, a hydrocarbon-containing gas line may be connected to the reactor 3.

[0012] <Operation of the hydrogen production device according to the first embodiment of the present disclosure> Next, the operation of the hydrogen production device 1 will be described. Iron ore is supplied to the reduction furnace 2, and a hydrogen-containing gas containing hydrogen generated by the operation described below is supplied to the reduction furnace 2. In the reduction furnace 2, the iron oxide in the iron ore reacts with the hydrogen in the hydrogen-containing gas, reducing the iron oxide to sponge iron. The sponge iron in the reduction furnace 2 is transferred to the reactor 3, and a hydrocarbon-containing gas is supplied to the reactor 3. In the reactor 3, the hydrocarbons in the hydrocarbon-containing gas come into contact with the sponge iron, and a direct decomposition reaction of the hydrocarbons occurs due to the catalytic action of the sponge iron, producing hydrogen and carbon. Because sponge iron is highly porous, the activation of the direct decomposition reaction of hydrocarbons increases more quickly than with less porous commercial-grade iron. Therefore, hydrogen is rapidly generated in the reactor 3 after the hydrocarbon-containing gas is supplied. Taking methane as an example of the hydrocarbon, the direct decomposition reaction of hydrocarbons is expressed as shown in the following chemical reaction formula (1). CH4 → 2H2 + C (1)

[0013] The reaction gas flowing out of the reactor 3 contains hydrogen produced by the direct decomposition reaction of hydrocarbons, and is supplied as a hydrogen-containing gas to the reduction furnace 2 via a hydrogen-containing gas line 4. In this way, hydrogen is produced by the direct decomposition method of hydrocarbons using sponge iron obtained by reducing iron ore with hydrogen as a catalyst. However, because sponge iron is highly porous, the activity of the direct decomposition reaction of hydrocarbons rises more quickly than with product-grade iron. This allows for efficient production of hydrogen for use in the hydrogen reduction ironmaking process.

[0014] <Modifications of the hydrogen production device according to the first embodiment of the present disclosure> Next, several modified examples of the hydrogen production apparatus 1 according to the first embodiment of the present disclosure will be described. As shown in FIG. 2, a separator 10 for separating hydrogen from the reaction gas flowing out from the reactor 3 may be provided in the hydrogen-containing gas line 4. The configuration of the separator 10 is not particularly limited, and any device having an arbitrary configuration, such as a pressure swing adsorption (PSA) device or a membrane separation device, can be used. The reaction gas flowing out from the reactor 3 contains unreacted hydrocarbons in addition to hydrogen produced by the direct cracking reaction of hydrocarbons. Therefore, if hydrogen is separated from the reaction gas by the separator 10 and the resulting hydrogen-containing gas with a high hydrogen concentration is supplied to the reduction furnace 2, the reduction efficiency of the iron ore can be improved.

[0015] In a configuration in which the separator 10 is provided in the hydrogen-containing gas line 4, a recycle line 11 may be further provided that connects the separator 10 to the hydrocarbon-containing gas line 7 so that the remaining components obtained by separating hydrogen from the reaction gas in the separator 10 are supplied to the hydrocarbon-containing gas flowing in the hydrocarbon-containing gas line 7. The remaining components obtained by separating hydrogen from the reaction gas in the separator 10 contain hydrocarbons that were unreacted in the reactor 3. Therefore, by supplying these components via the recycle line 11 to the hydrocarbon-containing gas flowing in the hydrocarbon-containing gas line 7 and returning them to the reactor 3, the hydrocarbons that were unreacted in the reactor 3 can be reused for the direct decomposition reaction of hydrocarbons. This reduces the amount of hydrocarbon-containing gas newly supplied to the reactor 3, thereby reducing the operating costs of the hydrogen production device 1.

[0016] 3, a combustor 12 (first combustor) that combusts a portion of the hydrocarbon-containing gas supplied to the reactor 3, and a heater 13 (first heater) that heats the inside of the reactor 3 with the combustion gas generated in the combustor 12 may be provided. A hydrocarbon-containing gas branch line 14 branching off from the hydrocarbon-containing gas line 7, and a combustion gas supply line 15 for supplying the combustion gas generated in the combustor 12 to the heater 13 are connected to the combustor 12.

[0017] When a portion of the hydrocarbon-containing gas flowing through the hydrocarbon-containing gas line 7 is supplied to the combustor 12 via the hydrocarbon-containing gas branch line 14, the hydrocarbons are combusted in the combustor 12 to generate combustion gas. The combustion gas is supplied to the heater 13 via the combustion gas supply line 15, and the inside of the reactor 3 is heated by the heat of the combustion gas. The configuration of the heater 13 is not particularly limited, and may be, for example, in the form of a jacket provided so as to form a space between the heater 13 and the outer peripheral surface of the reactor 3, in the form of a flow path formed inside the wall of the reactor 3, or in the form of piping provided so as to extend inside the reactor 3. When the heater 13 has these forms, heat exchange occurs between the combustion gas and the gas in the reactor 3 as the combustion gas flows through the space, the flow path, and the piping, and the latter is heated, thereby heating the inside of the reactor 3.

[0018] According to this configuration, the inside of the reactor 3 is heated by the heat of the combustion gas generated by burning a portion of the hydrocarbon-containing gas, which is the raw material for the direct decomposition reaction of hydrocarbons. This eliminates the need to prepare a separate heat source for heating the inside of the reactor 3, thereby simplifying the configuration of the hydrogen production device 1.

[0019] In the configuration including the combustor 12 and the heater 13, a combustion gas outlet line 16 through which the combustion gas that has heated the inside of the reactor 3 flows out from the heater 13, and a heat exchanger 17 for exchanging heat between the combustion gas flowing through the combustion gas outlet line 16 and the hydrogen-containing gas flowing through the hydrogen-containing gas line 4 may be further provided. According to this configuration, the hydrogen-containing gas is heated by the heat of the combustion gas after heating the inside of the reactor 3, so that the thermal efficiency of the entire hydrogen production apparatus 1 can be improved.

[0020] Instead of or in addition to the heat exchanger 17, a heater 18 (second heater) may be further provided for heating the iron ore with the combustion gas that has heated the inside of the reactor 3. When the heat exchanger 17 is not provided, the combustion gas outflow line 16 is configured to be connected to the heater 18, and when the heat exchanger 17 is provided, the combustion gas outflow branch line 19 branched from the combustion gas outflow line 16 is configured to be connected to the heater 18 (the latter configuration is shown in FIG. 3 ). The iron ore is heated by the combustion gas supplied to the heater 18 via the combustion gas outflow line 16 or the combustion gas outflow branch line 19, and the heated iron ore is supplied to the reduction furnace 2.

[0021] The heater 18 may have any configuration. For example, a cyclone may be used, in which the iron ore and the combustion gas are separated after contacting each other. When such a cyclone is provided in the iron ore line 5 as the heater 18, the iron ore is heated by contact with the combustion gas inside the cyclone, and the combustion gas flows out from the top of the cyclone, while the iron ore flows out from the bottom of the cyclone. The heated iron ore flowing out from the bottom of the cyclone is supplied to the reduction furnace 2 via the iron ore line 5. In this way, the iron ore is heated by the heat of the combustion gas after heating the inside of the reactor 3, thereby improving the thermal efficiency of the entire hydrogen production apparatus 1. Note that FIG. 3 illustrates a configuration in which the combustor 12, heater 13, heat exchanger 17, and heater 18 are provided in addition to the configuration of FIG. 1. However, these may also be provided in the configuration of FIG. 2. Even with this configuration, the same effects as those described above can be obtained.

[0022] As shown in FIG. 4 , when the reducing furnace 2 is configured to cool the sponge iron by bringing the cooling gas into contact with the sponge iron, part of the reaction gas flowing out from the reactor 3 may be used as part of the cooling gas. The configuration of this modification is described below. The reducing furnace 2 is connected to a cooling gas supply line 20 for supplying the cooling gas to the lower part of the reducing furnace 2, and a cooling gas outlet line 21 for discharging the cooling gas that has come into contact with the sponge iron in the lower part of the reducing furnace 2 from the reducing furnace 2. A compressor 22 is connected to the upstream end of the cooling gas supply line 20, and a scrubber 23 is connected to the downstream end of the cooling gas outlet line 21. The compressor 22 and the scrubber 23 are connected by a line 24. A first hydrogen-containing gas branch line 4a branches off from the hydrogen-containing gas line 4, and the first hydrogen-containing gas branch line 4a is connected to the cooling gas supply line 20.

[0023] The iron ore supplied to the reduction furnace 2 is converted into sponge iron by the iron oxide in the iron ore coming into contact with hydrogen and being reduced. Before being discharged from the outlet at the bottom of the reduction furnace 2, the sponge iron is cooled by contact with cooling gas supplied to the lower part of the reduction furnace 2 via a cooling gas supply line 20. The cooling gas that has cooled the sponge iron rises within the reduction furnace 2, and a portion of it flows out of the reduction furnace 2 via a cooling gas outlet line 21. The cooling gas flowing out of the reduction furnace 2 has fine particles and the like removed by a scrubber 23 and is then supplied to a compressor 22 via a line 24. The cooling gas is then pressurized by the compressor 22 and supplied again to the lower part of the reduction furnace 2 to cool the sponge iron. At this time, the reaction gas is supplied as part of the cooling gas to the lower part of the reduction furnace 2 via a first hydrogen-containing gas branch line 4a to cool the sponge iron.

[0024] According to this configuration, the reaction gas flowing out from the reactor 3 is used as part of the cooling gas for cooling the sponge iron in the reduction furnace 2, thereby reducing the amount of gas used as the cooling gas, and thus reducing the operating costs of the hydrogen production apparatus 1. Note that Fig. 4 shows a configuration in which the cooling gas supply line 20 and the first hydrogen-containing gas branch line 4a and the like are provided in addition to the configuration of Fig. 1, but these may also be provided in each of the configurations of Fig. 2 and Fig. 3, and similar effects can be obtained with these configurations.

[0025] A second hydrogen-containing gas branch line 4b separate from the first hydrogen-containing gas branch line 4a may branch off from the hydrogen-containing gas line 4. By connecting the second hydrogen-containing gas branch line 4b to a hydrogen consuming device that consumes hydrogen in another facility different from the hydrogen production device 1, it is possible to use hydrogen produced by a method that emits less carbon dioxide in the other facility. Note that the second hydrogen-containing gas branch line 4b is not limited to being added to the configuration shown in Fig. 1, but may also be added to the configurations shown in Figs. 2 and 3, thereby achieving similar effects.

[0026] (Embodiment 2) Next, a hydrogen production apparatus according to a second embodiment will be described. The hydrogen production apparatus according to the second embodiment differs from the first embodiment in that it uses steam-reformed gas obtained by steam-reforming natural gas as part of the hydrogen used in the reducing furnace 2. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted. Furthermore, unless otherwise specified, the term "configuration of the first embodiment" in the second embodiment does not mean to be limited to the configuration shown in FIG. 1, but also includes each modified example of the first embodiment (the configurations of FIGS. 2 to 4 and a configuration combining at least two of those configurations).

[0027] <Configuration of hydrogen production device according to embodiment 2 of the present disclosure> As shown in Fig. 5, the hydrogen production device 1 includes a steam reformer 30 that steam reforms natural gas. Connected to the steam reformer 30 are a natural gas line 31 for supplying natural gas to the steam reformer 30 and a steam reformed gas line 32 that communicates the steam reformer 30 with the hydrogen-containing gas line 4 so as to supply the steam reformed gas produced in the steam reformer 30 to the hydrogen-containing gas. A first natural gas branch line 33 branching from the natural gas line 31 is connected to the hydrocarbon-containing gas line 7. The other configurations are the same as those of the first embodiment.

[0028] <Operation of the hydrogen production device according to the second embodiment of the present disclosure> A portion of the natural gas flowing through the natural gas line 31 flows into the reactor 3 via the first natural gas branch line 33 and the hydrocarbon-containing gas line 7, and is used as a raw material for the direct cracking reaction of hydrocarbons. The remaining natural gas flowing through the natural gas line 31 is supplied to the steam reformer 30, where the hydrocarbons contained in the natural gas are steam reformed to produce a steam-reformed gas containing hydrogen and carbon monoxide. The steam-reformed gas flowing out of the steam reformer 30 is supplied to the hydrogen-containing gas line 4 via the steam reformed gas line 32, mixed with the hydrogen-containing gas flowing through the hydrogen-containing gas line 4, and supplied to the reduction furnace 2 as part of the hydrogen-containing gas. In this way, natural gas can be used as a raw material for the direct cracking reaction of hydrocarbons, making it easier to prepare the raw material for the direct cracking reaction of hydrocarbons.

[0029] <Modification of the hydrogen production device according to the second embodiment of the present disclosure> Next, several modified examples of the hydrogen production apparatus 1 according to the second embodiment of the present disclosure will be described. As shown in Fig. 6, a methanation apparatus 34 may be further provided, which is connected to the first natural gas branch line 33 and to the hydrocarbon-containing gas line 7. The methanation apparatus 34 converts at least a portion of hydrocarbons other than methane (hydrocarbons having two or more carbon atoms) in the natural gas supplied via the first natural gas branch line into methane by reacting them with hydrogen. For this reason, a hydrogen supply line 35 for supplying hydrogen to the methanation apparatus 34 is connected to the methanation apparatus 34.

[0030] The hydrocarbons methanated in the methanation unit 34 are primarily hydrocarbons containing unsaturated bonds, such as ethylene and propylene. Addition of hydrogen to the unsaturated bonds in such hydrocarbons breaks the bonds between carbon atoms, resulting in decomposition into hydrocarbons with a smaller carbon number, preferably methane. While hydrocarbons other than methane may be included in the raw material for the direct hydrocarbon cracking reaction, hydrocarbons with a larger carbon number tend to be directly cracked at lower temperatures than methane. The higher the concentration of hydrocarbons with a larger carbon number, the more difficult it is to control the temperature of the reactor 3. In contrast, in the modified example of the second embodiment shown in FIG. 6 , hydrocarbons with a larger carbon number contained in natural gas are methanated in the methanation unit 34 and supplied to the reactor 3, making it easier to control the temperature of the reactor 3.

[0031] The provision of the methanation device 34 does not necessarily require the configuration of Fig. 5. The methanation device 34 may be provided in the configuration of embodiment 1. For example, as shown in Fig. 7, the methanation device 34 (including the hydrogen supply line 35) may be provided in the hydrocarbon-containing gas line 7 in the configuration of Fig. 1. The methanation device 34 of this configuration is a device that converts at least a portion of hydrocarbons other than methane (hydrocarbons having two or more carbon atoms) in the hydrocarbon-containing gas into methane by reacting them with hydrogen.

[0032] As shown in Fig. 8, the reactor 3 may be configured so that the interior thereof is heated by combustion gas generated by combusting a portion of the natural gas supplied to the reactor 3. The configuration of this modified example will be described below. A combustor 36 (second combustor) that burns natural gas is provided, and a second natural gas branch line 37 branching off from the natural gas line 31 is connected to the combustor 36. Note that the configuration in which the second natural gas branch line 37 branches off from the natural gas line 31 also includes a configuration in which, when a first natural gas branch line 33 branching off from the natural gas line 31 exists, the line branching off from the natural gas line 31 branches off into the first natural gas branch line 33 and the second natural gas branch line 37.

[0033] In this modification, similar to the modification of the first embodiment shown in FIG. 3, a heater 13 is provided that heats the inside of the reactor 3 with the combustion gas generated in the combustor 36. The combustor 36 is connected to the heater 13 via a combustion gas supply line 15. Also, similar to the modification of the first embodiment shown in FIG. 3, at least one of a heat exchanger 17 and a heater 18 that heat the hydrogen-containing gas and the iron ore with the combustion gas flowing out from the heater 13 may be provided. The configurations of these modifications shown in FIG. 8 can achieve the same effects as the modification of the first embodiment shown in FIG. 3. Note that although these configurations shown in FIG. 8 are described as modifications to the configuration of FIG. 5, they may also be configured as modifications to the configuration of FIG. 6 (a configuration provided with a methanation device 34).

[0034] <Modifications of the hydrogen production devices according to the first and second embodiments of the present disclosure> 1 to 8, the hydrogen-containing gas supplied to the reducing furnace 2 is depicted as being only the hydrogen-containing gas containing hydrogen produced in the reactor 3. However, the present invention is not limited to this configuration, and in addition to the hydrogen-containing gas containing hydrogen produced in the reactor 3, a hydrogen-containing gas from a separate system may be supplied to the reducing furnace 2. For example, the hydrogen supply source and the reducing furnace 2 may be connected to each other through a pipe, and hydrogen may be supplied from the hydrogen supply source to the reducing furnace 2 through this pipe. Alternatively, this pipe may be joined to the hydrogen-containing gas line 4 and then connected to the reducing furnace 2.

[0035] [Ironmaking equipment] <Configuration of iron making apparatus according to one embodiment of the present disclosure> Fig. 9 shows a configuration block diagram of a hydrogen production device according to one embodiment of the present disclosure, specifically, a steel making apparatus 50 equipped with the hydrogen production device 1 according to embodiment 1 shown in Fig. 1. The hydrogen production device 1 equipped in the steel making apparatus 50 described below is a hydrogen production device having the configuration shown in Fig. 1, but is not limited to this configuration and may be a hydrogen production device having the configurations of embodiments 1 and 2 and their respective modified examples, i.e., a hydrogen production device having the configurations shown in each of Figs. 2 to 8.

[0036] The steelmaking apparatus 50 includes a hydrogen production apparatus 1 and a refining furnace 51 for refining sponge iron obtained by reducing iron ore with hydrogen in a reduction furnace 2. The refining furnace 51 may be, for example, a converter or an electric furnace. A sponge iron branch line 52 branches off from the sponge iron line 6 and is connected to the refining furnace 51. A distributor 53 is provided at the branch point where the sponge iron branch line 52 branches off from the sponge iron line 6 for adjusting the amount of sponge iron distributed from the reduction furnace 2 to the reactor 3 and the refining furnace 51. The configuration of the distributor 53 is not particularly limited, and it may, for example, be configured to include a hopper provided between the reduction furnace 2 and the refining furnace 51 for temporarily storing the sponge iron and a metering feeder for discharging the sponge iron from the hopper. In this configuration, the amount of sponge iron distributed to the reactor 3 and the refining furnace 51 can be adjusted by adjusting the feed rate of the metering feeder.

[0037] <Operation of the iron making apparatus according to an embodiment of the present disclosure> The operation of the hydrogen production apparatus 1 is as described above. In the steelmaking apparatus 50, the sponge iron flowing out from the reduction furnace 2 is not all supplied to the reactor 3, but is supplied to the reactor 3 and the refining furnace 51 in a distributed amount adjusted by the distributor 53. The sponge iron supplied to the refining furnace 51 is refined into iron products such as steel. In this way, ironmaking is performed by hydrogen reduction of iron ore using hydrogen produced by the direct decomposition reaction of hydrocarbons, thereby realizing a decarbonized ironmaking process.

[0038] If the distributor 53 is configured to supply all of the sponge iron flowing out of the reduction furnace 2 to the reactor 3, the iron-making apparatus 50 will function as the above-mentioned hydrogen production apparatus 1. If hydrogen can be supplied to the reduction furnace 2 from a source other than the reactor 3, the distributor 53 can be configured to supply all of the sponge iron flowing out of the reduction furnace 2 to the smelting furnace 51, so that the iron-making apparatus 50 will function as an apparatus that only produces iron. Furthermore, by arbitrarily adjusting the amounts of sponge iron distributed to the reactor 3 and the smelting furnace 51 by the distributor 53, the ratio between the amount of hydrogen generated and the amount of iron products produced can be arbitrarily adjusted.

[0039] <Modification of iron making device according to an embodiment of the present disclosure> The reactor 3 may further include a catalyst supply line 54 for supplying at least a portion of the catalyst in the reactor 3 to the refining furnace 51. With this configuration, the carbon-coated catalyst can be used as a recarburizer in the refining furnace 51 after the direct decomposition of hydrocarbons, thereby reducing the amount of catalyst discarded after the direct decomposition of hydrocarbons.

[0040] The contents described in each of the above embodiments can be understood, for example, as follows.

[0041] [1] A hydrogen production device according to one aspect includes: a reduction furnace (2) for reducing iron ore with a hydrogen-containing gas containing hydrogen; a reactor (3) for directly decomposing hydrocarbons by bringing a hydrocarbon-containing gas into contact with a catalyst that is at least a part of the sponge iron obtained by reducing the iron ore in the reduction furnace (2); a hydrogen-containing gas line (4) for supplying at least a portion of the reaction gas flowing out from the reactor (3) to the reduction furnace (2) as at least a portion of the hydrogen-containing gas; Equipped with.

[0042] The hydrogen production device disclosed herein produces hydrogen by the direct decomposition of hydrocarbons using sponge iron, obtained by reducing iron ore with hydrogen, as a catalyst. Because sponge iron is highly porous, the activation of the direct decomposition reaction of hydrocarbons increases more quickly than with commercial-grade iron. This allows for efficient production of hydrogen for use in the hydrogen reduction ironmaking process.

[0043] [2] A hydrogen production device according to another embodiment is the hydrogen production device according to [1], a first combustor (12) for combusting a portion of the hydrocarbon-containing gas; a first heater (13) that heats the inside of the reactor (3) with combustion gas generated in the first combustor (12); Further provided are:

[0044] With this configuration, the inside of the reactor is heated by the heat of the combustion gas generated by burning a portion of the hydrocarbon-containing gas, which is the raw material for the direct decomposition reaction of hydrocarbons. This eliminates the need to prepare a separate heat source for heating the inside of the reactor, thereby simplifying the configuration of the hydrogen production device.

[0045] [3] A hydrogen production device according to yet another embodiment is the hydrogen production device according to [2], The system further includes a heat exchanger (17) that heats the hydrogen-containing gas by exchanging heat between the combustion gas flowing out from the first heater (13) and the hydrogen-containing gas.

[0046] According to this configuration, the hydrogen-containing gas is heated by the heat of the combustion gas after heating the inside of the reactor, so that the thermal efficiency of the entire hydrogen production apparatus can be improved.

[0047] [4] A hydrogen production device according to yet another embodiment is the hydrogen production device according to [2] or [3], The reduction furnace further includes a second heater (18) that heats the iron ore to be supplied to the reduction furnace (2) with the combustion gas flowing out from the first heater (13).

[0048] According to this configuration, the iron ore is heated by the heat of the combustion gas after heating the inside of the reactor, and therefore the thermal efficiency of the entire hydrogen production apparatus can be improved.

[0049] [5] A hydrogen production device according to yet another embodiment is the hydrogen production device according to any one of [1] to [4], a hydrocarbon-containing gas line (7) for supplying the hydrocarbon-containing gas to the reactor (3); a methanation device (34) provided in the hydrocarbon-containing gas line (7); a hydrogen supply line (35) for supplying hydrogen to the methanation unit (34); Furthermore, The methanation unit (34) is a unit that converts at least a portion of the hydrocarbons other than methane in the hydrocarbon-containing gas into methane by reacting them with hydrogen supplied via the hydrogen supply line (35).

[0050] [6] A hydrogen production device according to yet another embodiment is the hydrogen production device according to [1], a steam reformer (30) for steam reforming natural gas; a natural gas line (31) for supplying the natural gas to the steam reformer (30); a steam reformed gas line (32) communicating the steam reformer (30) with the hydrogen-containing gas line (4) so ​​as to supply the steam reformed gas produced in the steam reformer (30) to the hydrogen-containing gas; a hydrocarbon-containing gas line (7) for supplying the hydrocarbon-containing gas to the reactor (3); a first natural gas branch line (33) branching from the natural gas line (31) and connected to the hydrocarbon-containing gas line (7); Further provided are:

[0051] According to this configuration, natural gas can be used as the raw material for the direct cracking reaction of hydrocarbons, which makes it easy to prepare the raw material for the direct cracking reaction of hydrocarbons.

[0052] [7] A hydrogen production device according to yet another embodiment is the hydrogen production device according to [6], a methanation unit (34) connected to the first natural gas branch line (33) and to the hydrocarbon-containing gas line (7); a hydrogen supply line (35) for supplying hydrogen to the methanation unit (34); Furthermore, The methanation unit (34) is a unit that converts at least a portion of hydrocarbons other than methane in the natural gas supplied via the first natural gas branch line (33) into methane by reacting them with hydrogen supplied via the hydrogen supply line (35).

[0053] According to this configuration, the concentration of hydrocarbons with a carbon number of 2 or more contained in natural gas is reduced and a hydrocarbon-containing gas with an increased concentration of methane is supplied to the reactor, making it easier to control the temperature of the reactor.

[0054] [8] A hydrogen production device according to yet another embodiment is the hydrogen production device according to [6] or [7], a second natural gas branch line (37) branching off from the natural gas line (31); a second combustor (36) that combusts the natural gas supplied via the second natural gas branch line (37); a first heater (13) for heating the inside of the reactor (3) with combustion gas generated in the second combustor (36); Further provided are:

[0055] With this configuration, the inside of the reactor is heated by the heat of the combustion gas produced by burning a portion of the natural gas that is the raw material for the direct cracking reaction of hydrocarbons. This eliminates the need to prepare a separate heat source for heating the inside of the reactor, thereby simplifying the configuration of the hydrogen production device.

[0056] [9] A hydrogen production device according to yet another embodiment is the hydrogen production device according to [8], The system further includes a heat exchanger (17) that heats the hydrogen-containing gas by exchanging heat between the combustion gas flowing out from the first heater (13) and the hydrogen-containing gas.

[0057] According to this configuration, the hydrogen-containing gas is heated by the heat of the combustion gas after heating the inside of the reactor, so that the thermal efficiency of the entire hydrogen production apparatus can be improved.

[0058]

[10] A hydrogen production device according to yet another embodiment is the hydrogen production device according to [8] or [9], The reduction furnace further includes a second heater (18) that heats the iron ore to be supplied to the reduction furnace (2) with the combustion gas flowing out from the first heater (13).

[0059] According to this configuration, the iron ore is heated by the heat of the combustion gas after heating the inside of the reactor, so that the thermal efficiency of the entire hydrogen production apparatus can be improved.

[0060]

[11] A hydrogen production device according to yet another embodiment is the hydrogen production device according to any one of [1] to

[10] , The system further includes a separator (10) provided in the hydrogen-containing gas line (4) for separating hydrogen from the reaction gas flowing out of the reactor (3).

[0061] According to this configuration, the reaction gas flowing out from the reactor is separated into hydrogen and hydrocarbons, and the hydrogen-containing gas with a high hydrogen concentration is supplied to the reduction furnace, thereby increasing the efficiency of reduction of iron ore.

[0062]

[12] A hydrogen production device according to yet another embodiment is the hydrogen production device according to

[11] , a hydrocarbon-containing gas line (7) for supplying the hydrocarbon-containing gas to the reactor (3); a recycle line (11) communicating the separator (10) with the hydrocarbon-containing gas line (7) so as to supply the remaining components obtained by separating hydrogen from the reaction gas in the separator (10) to the hydrocarbon-containing gas flowing through the hydrocarbon-containing gas line (7); Further provided are:

[0063] According to this configuration, the unreacted hydrocarbons in the reactor can be reused for the direct decomposition reaction of hydrocarbons, thereby reducing the amount of hydrocarbon-containing gas newly supplied to the reactor and reducing the operating costs of the hydrogen production device.

[0064]

[13] A hydrogen production device according to yet another embodiment is the hydrogen production device according to any one of [1] to

[12] , a first hydrogen-containing gas branch line (4a) branching from the hydrogen-containing gas line (4); a cooling gas supply line (20) for supplying the cooling gas to the reduction furnace (2) so that the cooling gas is brought into contact with the sponge iron in the reduction furnace (2) to cool the sponge iron; Furthermore, The first hydrogen-containing gas branch line (4a) is connected to the cooling gas supply line (20).

[0065] According to this configuration, by using the reaction gas flowing out from the reactor as part of the cooling gas for cooling the sponge iron in the reduction furnace, the amount of gas used as the cooling gas can be reduced, thereby reducing the operating costs of the hydrogen production apparatus.

[0066]

[14] A hydrogen production device according to yet another embodiment is the hydrogen production device according to any one of [1] to

[13] , The system further includes a second hydrogen-containing gas branch line (4b) branching off from the hydrogen-containing gas line (4).

[0067] According to this configuration, the hydrogen-containing gas can be used in another facility different from the hydrogen production device via the second hydrogen-containing gas branch line.

[0068]

[15] An iron making apparatus according to one aspect includes: A hydrogen production device (1) according to any one of [1] to

[14] , a smelting furnace (51) for refining a portion of the sponge iron; Equipped with.

[0069] According to the iron-making apparatus disclosed herein, iron is made by hydrogen reduction of iron ore using hydrogen produced by the direct decomposition reaction of hydrocarbons, thereby realizing a decarbonized iron-making process.

[0070]

[16] Another aspect of the iron making apparatus is the iron making apparatus according to

[15] , The reactor (3) further includes a catalyst supply line (54) for supplying at least a portion of the catalyst in the reactor (3) to the refining furnace.

[0071] According to this configuration, the carbon-coated catalyst can be used as a recarburizer in the refining furnace after the direct decomposition of hydrocarbons, thereby reducing the amount of catalyst discarded after the direct decomposition of hydrocarbons. [Explanation of symbols]

[0072] 1. Hydrogen production equipment 2. Reduction furnace 3. Reactor 4 Hydrogen-containing gas line 4a First hydrogen-containing gas branch line 4b Second hydrogen-containing gas branch line 7 Hydrocarbon-containing gas lines 10 Separator 11 Recycling Line 12 Combustor (First Combustor) 13 Heater (1st heater) 17 Heat exchanger 18 Heater (second heater) 20 Cooling gas supply line 30 Steam reformer 31 Natural Gas Line 32 Steam reforming gas line 33 No. 1 Natural Gas Branch Line 34 Methanation Unit 35 Hydrogen supply line 36 Combustor (second combustor) 37 Second natural gas branch line 50 Iron and steel making equipment 51 Smelting Furnace 54 Catalyst supply line

Claims

1. a reduction furnace for reducing iron ore with a hydrogen-containing gas containing hydrogen; a reactor for directly decomposing hydrocarbons by bringing a hydrocarbon-containing gas into contact with a catalyst that is at least a part of the sponge iron obtained by reducing the iron ore in the reduction furnace; a hydrogen-containing gas line for supplying at least a portion of the reaction gas flowing out from the reactor to the reduction furnace as at least a portion of the hydrogen-containing gas; A hydrogen production device comprising:

2. a first combustor for combusting a portion of the hydrocarbon-containing gas; a first heater that heats the inside of the reactor with combustion gas generated in the first combustor; The hydrogen production device according to claim 1 , further comprising:

3. The hydrogen production device according to claim 2 , further comprising a heat exchanger that heats the hydrogen-containing gas by exchanging heat between the combustion gas flowing out from the first heater and the hydrogen-containing gas.

4. 4. The hydrogen production apparatus according to claim 2, further comprising a second heater configured to heat the iron ore supplied to the reduction furnace with the combustion gas flowing out from the first heater.

5. a hydrocarbon-containing gas line for supplying the hydrocarbon-containing gas to the reactor; a methanation device provided in the hydrocarbon-containing gas line; a hydrogen supply line for supplying hydrogen to the methanation device; Furthermore, The hydrogen production device according to any one of claims 1 to 3, wherein the methanation device is a device that converts at least a portion of hydrocarbons other than methane in the hydrocarbon-containing gas into methane by reacting them with hydrogen supplied via the hydrogen supply line.

6. a steam reformer for steam reforming natural gas; a natural gas line for supplying the natural gas to the steam reformer; a steam reformed gas line communicating the steam reformer with the hydrogen-containing gas line so as to supply the steam reformed gas generated in the steam reformer to the hydrogen-containing gas; a hydrocarbon-containing gas line for supplying the hydrocarbon-containing gas to the reactor; a first natural gas branch line branching from the natural gas line and connected to the hydrocarbon-containing gas line; The hydrogen production device according to claim 1 , further comprising:

7. a methanator connected to the first natural gas branch line and connected to the hydrocarbon-containing gas line; a hydrogen supply line for supplying hydrogen to the methanation device; Furthermore, 7. The hydrogen production apparatus according to claim 6, wherein the methanation unit converts at least a portion of hydrocarbons other than methane in the natural gas supplied via the first natural gas branch line into methane by reacting them with hydrogen supplied via the hydrogen supply line.

8. a second natural gas branch line branching off from the natural gas line; a second combustor that combusts the natural gas supplied through the second natural gas branch line; a first heater that heats the inside of the reactor with the combustion gas generated in the second combustor; The hydrogen production device according to claim 6 or 7, further comprising:

9. The hydrogen production device according to claim 8 , further comprising a heat exchanger that heats the hydrogen-containing gas by exchanging heat between the combustion gas flowing out from the first heater and the hydrogen-containing gas.

10. 9. The hydrogen production apparatus according to claim 8, further comprising a second heater that heats the iron ore supplied to the reduction furnace with the combustion gas flowing out from the first heater.

11. 8. The hydrogen production device according to claim 1, further comprising a separator provided in the hydrogen-containing gas line for separating hydrogen from the reaction gas flowing out from the reactor.

12. a hydrocarbon-containing gas line for supplying the hydrocarbon-containing gas to the reactor; a recycle line communicating the separator with the hydrocarbon-containing gas line so as to supply the remaining components obtained by separating hydrogen from the reaction gas in the separator to the hydrocarbon-containing gas flowing through the hydrocarbon-containing gas line; The hydrogen production device according to claim 11, further comprising:

13. a first hydrogen-containing gas branch line branching from the hydrogen-containing gas line; a cooling gas supply line for supplying the cooling gas to the reduction furnace so as to cool the sponge iron by bringing the cooling gas into contact with the sponge iron in the reduction furnace; Furthermore, 8. The hydrogen production device according to claim 1, wherein the first hydrogen-containing gas branch line is connected to the cooling gas supply line.

14. 8. The hydrogen production device according to claim 1, further comprising a second hydrogen-containing gas branch line branching off from the hydrogen-containing gas line.

15. The hydrogen production device according to any one of claims 1 to 3, 6 and 7; a smelting furnace for refining a portion of the sponge iron; A steelmaking apparatus comprising:

16. 16. The iron making apparatus of claim 15, further comprising a catalyst supply line for supplying at least a portion of the catalyst in the reactor to the smelting furnace.

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