Methods for manufacturing valuable materials

Abstract

To provide a carbon material manufacturing apparatus, a carbon material manufacturing system, and a carbon material manufacturing method that can efficiently produce carbon materials from carbon dioxide. [Solution] According to one aspect of the present invention, an apparatus for producing carbon materials is provided. This apparatus comprises a first reaction unit for producing carbon monoxide from carbon dioxide, a second reaction unit for producing carbon materials from carbon monoxide, and a gas line connecting the first reaction unit and the second reaction unit. The first reaction unit has at least one reactor containing a reducing agent. The reducing agent is brought into contact with a raw material gas containing carbon dioxide to reduce carbon dioxide into carbon monoxide and is also brought into an oxidized state, and the oxidized reducing agent is reduced by contact with a reducing gas containing a reducing substance.

Description

Technical Field

[0001] The present invention relates to a carbon material production apparatus, a carbon material production system, a carbon circulation system, a carbon material production method, and a carbon circulation method.

Background Art

[0002] Carbon materials are widely used as conductive materials for electronic devices, filler materials for tires and inks, and the like. For example, Patent Document 1 discloses a method for producing a carbon material by burning coal. However, in such a method, it is considered that a large amount of carbon dioxide (CO2) is contained in the gas from which the carbon material is separated in the final step. If this separated gas is directly released into the atmosphere, there is a concern that the concentration of carbon dioxide in the atmosphere will increase, contributing to global warming.

[0003] In recent years, the development of lithium-ion secondary batteries has been underway. In addition, in order to improve the characteristics of lithium-ion secondary batteries, active materials used for the positive and negative electrodes are actively studied. For example, Patent Document 2 discloses a method for producing a carbon-based negative electrode active material excellent in lithium ion acceptance. In the method of Patent Document 2, a method of pulverizing petroleum-based or coal-based coke, adjusting the particle size, and then performing heat treatment is disclosed.

[0004] For example, the carbon material produced by the method disclosed in Patent Document 1 can also be used as the above carbon-based negative electrode active material. However, when using such a method, as described above, there is a concern that the concentration of carbon dioxide in the atmosphere will increase, contributing to global warming.

[0005] Conventionally, in smelting, coke as a reducing agent is charged into a blast furnace together with ore as a raw material, and the ore is melted to extract the target metal. Coke is usually produced from coal (see Patent Document 2). Coal is a type of fossil fuel, and burning it releases large amounts of carbon dioxide. Releasing this carbon dioxide directly into the atmosphere raises concerns that it will increase the concentration of carbon dioxide in the atmosphere and exacerbate global warming. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2014-19620 [Patent Document 2] International Publication No. 2009 / 022664 [Patent Document 3] Japanese Patent Publication No. 2021-50279 [Overview of the project] [Problems that the invention aims to solve]

[0007] In view of the above circumstances, the present invention aims to provide a carbon material manufacturing apparatus, a carbon material manufacturing system, and a carbon material manufacturing method that can efficiently produce carbon materials from carbon dioxide.

[0008] Furthermore, according to the inventors' studies, carbon-based anode active materials produced from coke have a low content of impurities (solid impurities) due to the relatively low impurity content of coke itself. From the viewpoint of further improving the characteristics of lithium-ion secondary batteries, it is desirable to further reduce the content of solid impurities in carbon-based anode active materials (carbon materials). It is also desirable that the manufacturing process has a low environmental impact. Therefore, in light of the above circumstances, we have decided to provide a carbon material manufacturing apparatus, etc., that can produce carbon materials with an extremely low solid impurity content while preventing environmental impact during manufacturing.

[0009] Furthermore, in view of the above circumstances, the present invention provides a carbon recycling system and a carbon recycling method that can efficiently produce a target metal using carbon materials generated from exhaust gas. [Means for solving the problem]

[0010] According to one aspect of the present invention, an apparatus for producing a carbon material is provided. This apparatus comprises a first reaction unit for producing carbon monoxide from carbon dioxide, a second reaction unit for producing a carbon material from carbon monoxide, and a gas line connecting the first reaction unit and the second reaction unit. The first reaction unit has at least one reactor containing a reducing agent. The reducing agent is brought into contact with a raw material gas containing carbon dioxide to reduce carbon dioxide into carbon monoxide and is also brought into an oxidized state, and the oxidized reducing agent is reduced by contact with a reducing gas containing a reducing substance.

[0011] According to this embodiment, carbon materials can be efficiently produced from carbon dioxide.

[0012] According to another aspect of the present invention, an apparatus for producing carbon materials is provided. This apparatus comprises a first reaction unit for producing carbon monoxide from carbon dioxide, a second reaction unit for producing carbon materials from carbon monoxide, a gas line connecting the first reaction unit and the second reaction unit, and a pressure adjustment unit provided in the middle of the gas line for increasing the pressure of the gas passing through the gas line.

[0013] According to this embodiment, carbon materials can be efficiently produced from carbon dioxide.

[0014] According to another aspect of the present invention, an apparatus for producing a carbon material is provided. This apparatus comprises a first reaction section for producing carbon monoxide from carbon dioxide and a second reaction section for producing a carbon material from carbon monoxide. The content of solid impurities in the carbon material is 1% by mass or less.

[0015] According to this embodiment, it is possible to manufacture carbon materials with extremely low impurity content while preventing environmental impact during manufacturing. Furthermore, by effectively utilizing exhaust gases, emissions can be reduced, thereby realizing a circular economy (a society based on the recycling of materials).

[0016] According to still another aspect of the present invention, a carbon circulation system is provided. The reducing agent includes a first reaction unit that generates carbon monoxide from carbon dioxide contained in exhaust gas, a second reaction unit that generates a carbon material from carbon monoxide, and a melting furnace that supplies an ore together with the carbon material and smelts it. The first reaction unit houses a reducing agent that is converted into carbon monoxide by a reduction reaction of carbon dioxide caused by contact with the exhaust gas, and has at least one reactor capable of separating at least a part of the oxygen element separated from the carbon dioxide within the reduction reaction system. The reducing agent is a reducing agent that reduces carbon dioxide by contact with the exhaust gas to convert it into carbon monoxide and is oxidized, and the oxidized reducing agent is a reducing agent that is reduced by contact with a reducing gas containing a reducing substance.

[0017] According to such an aspect, it is possible to efficiently produce a target metal using the carbon material generated from the exhaust gas. Further, by effectively utilizing the exhaust gas, its emission amount can be reduced, and a circular economy (a material recycling-based society) can be realized.

Brief Description of the Drawings

[0018] [Figure 1] It is a schematic diagram showing the configuration of a first embodiment of a carbon material production system of the present invention. [Figure 2] It is a schematic diagram showing the configuration of the first reactor in the first embodiment. [Figure 3] It is a schematic diagram showing the configuration of a second embodiment of a carbon material production system of the present invention. [Figure 4] It is a schematic diagram showing the configuration of a third embodiment of a carbon material production system of the present invention. [Figure 5] It is a schematic diagram showing the configuration of the first reaction unit in the fourth embodiment. [Figure 6] It is a schematic diagram showing the configuration of a fifth embodiment of a carbon material production system of the present invention. [Figure 7] It is a schematic diagram showing the configuration of a sixth embodiment of a carbon material production system of the present invention. [Figure 8]This is a schematic diagram showing the configuration of a seventh embodiment of the carbon material manufacturing system of the present invention. [Figure 9] This is a schematic diagram showing the configuration of a first embodiment of the carbon recycling system of the present invention. [Figure 10] This is a schematic diagram showing the configuration of a second embodiment of the carbon cycle system of the present invention. [Figure 11] This is a schematic diagram showing the configuration of a third embodiment of the carbon cycle system of the present invention. [Figure 12] This is a schematic diagram showing the configuration of a fourth embodiment of the carbon cycle system of the present invention. [Modes for carrying out the invention]

[0019] The carbon material manufacturing apparatus, carbon material manufacturing system, carbon recycling system, carbon material manufacturing method, and carbon recycling method of the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings. <Carbon material manufacturing system> Firstly, the carbon material manufacturing system of the present invention will be described. <<First Embodiment>> First, a first embodiment of the carbon material manufacturing system of the present invention will be described. Figure 1 is a schematic diagram showing the configuration of a first embodiment of the carbon material manufacturing system of the present invention. Figure 2 is a schematic diagram showing the configuration of the first reactor in the first embodiment. The carbon material manufacturing system 10 shown in Figure 1 is a manufacturing system for manufacturing carbon materials, and comprises a carbon material manufacturing apparatus 100 (hereinafter also simply referred to as "manufacturing apparatus 100"), an exhaust gas supply unit 1 connected to the manufacturing apparatus 100 and supplying exhaust gas (raw material gas containing carbon dioxide), and a reducing gas supply unit 2 that supplies reducing gas. In this specification, the upstream side with respect to the direction of gas flow will also be simply referred to as the "upstream side," and the downstream side will also be simply referred to as the "downstream side."

[0020] The exhaust gas supply unit 1 is not particularly limited, but for example, it can supply CO2 from at least one business selected from waste incineration plants, paper mills, cement plants, steel mills, smelters, thermal power plants, oil refineries, ethylene crackers, oil refineries, and chemical plants. x Emission sources can be cited. Among these, furnaces attached to steel mills, smelters, or thermal power plants (e.g., combustion furnaces, blast furnaces, converters) are preferred as the exhaust gas supply unit 1. In furnaces, gases containing carbon dioxide are generated during the combustion, melting, and refining of the contents. In the case of incinerators at waste incineration plants, examples of contents (waste) include plastic waste, food waste, municipal waste (MSW), discarded tires, biomass waste, household waste (bedding, paper products), and building materials. These wastes may consist of one type alone or two or more types.

[0021] Exhaust gas typically contains carbon dioxide, as well as other gaseous components such as nitrogen, oxygen, carbon monoxide, water vapor, and methane. The concentration of carbon dioxide in the exhaust gas is not particularly limited, but considering the production cost of the generated gas (conversion efficiency to carbon materials), it is preferably 1 volume% or more, and more preferably 5 volume% or more. In the case of exhaust gas from combustion furnaces at waste incineration plants, it contains carbon dioxide at a ratio of 5% to 15% by volume, nitrogen at a ratio of 60% to 70% by volume, oxygen at a ratio of 5% to 10% by volume, and water vapor at a ratio of 15% to 25% by volume.

[0022] Blast furnace exhaust gas (blast furnace gas) is a gas produced during the manufacturing of pig iron in a blast furnace, and contains carbon dioxide at a ratio of 5% to 45% by volume, nitrogen at a ratio of 55% to 60% by volume, carbon monoxide at a ratio of 10% to 40% by volume, and hydrogen at a ratio of 1% to 10% by volume. Furthermore, the exhaust gas from the converter (converter gas) is a gas generated during the production of steel in the converter, and contains carbon dioxide at a concentration of 15% to 20% by volume, carbon monoxide at a concentration of 50% to 80% by volume, nitrogen at a concentration of 15% to 25% by volume, and hydrogen at a concentration of 1% to 5% by volume. Furthermore, pure gas containing 100% by volume of carbon dioxide may be used as the exhaust gas.

[0023] However, by using exhaust gas, carbon dioxide that would have been released into the atmosphere can be effectively utilized, thereby reducing the burden on the environment. Among these, exhaust gas containing carbon dioxide generated at steel mills or smelters is preferred from the perspective of the carbon cycle. Furthermore, the blast furnace gas and converter gas may be the untreated gas discharged from the furnace as is, or treated gas (described later) that has been treated to remove carbon monoxide, etc., may be used. The untreated blast furnace gas and converter gas have the gas compositions described above, respectively, while the treated gas has a gas composition similar to that of the exhaust gas from the combustion furnace. In this specification, all of the above gases (gases before being supplied to the manufacturing apparatus 100) are referred to as exhaust gas.

[0024] The reducing gas supply unit 2 consists of, for example, a hydrogen generator that produces hydrogen by electrolysis of water. A tank containing water is connected to this hydrogen generator. The hydrogen generator allows for the relatively inexpensive and simple production of large quantities of hydrogen. It also has the advantage of reusing the condensed water generated within the production device 100 (and the carbon cycle system 1000 described later). However, because the hydrogen generator consumes a significant amount of electrical energy, it is effective to use electricity as a renewable energy source. As for renewable energy sources, electrical energy can be used that utilizes at least one selected from solar power, wind power, hydropower, wave power, tidal power, biomass power, geothermal power, solar thermal, and ground source thermal energy.

[0025] Furthermore, hydrogen generators can also utilize devices that produce by-product hydrogen. Examples of devices that produce by-product hydrogen include devices that electrolyze sodium chloride aqueous solutions, devices that steam reform petroleum, and devices that produce ammonia. Alternatively, the reducing gas supply unit 2 can be a coke oven. In this case, exhaust gas from the coke oven may be used as the reducing gas. This is because exhaust gas from a coke oven mainly consists of hydrogen and methane, and contains hydrogen in an amount of 50% to 60% by volume.

[0026] The manufacturing apparatus 100 of this embodiment is an apparatus for manufacturing carbon material and mainly comprises a gas switching unit 3, two first reactors 4a and 4b (first reaction unit 4), and one second reactor (second reaction unit) 5. The exhaust gas supply unit 1 is connected to the gas switching unit 3 via the gas line GL1, and the recirculating gas supply unit 2 is connected to the gas switching unit 3 via the gas line GL2. Each gas line GL1, GL2 may be equipped with at least one of the following: a temperature control unit to adjust the temperature of the gas passing through it, a pressurizing unit to pressurize the gas, or an impurity removal unit to remove impurities from the gas. The gas switching unit 3 can be configured, for example, to include a branched gas line and a flow path opening / closing mechanism, such as a valve, provided in the middle of the branched gas line.

[0027] The gas switching unit 3 is connected to the inlet ports of the first reactors 4a and 4b, respectively, via two gas lines GL3a and GL3b. With this configuration, the exhaust gas (raw material gas containing carbon dioxide) supplied from the exhaust gas supply unit 1 passes through gas line GL1, gas switching unit 3, and gas lines GL3a and GL3b, and is supplied to the first reactors 4a and 4b, respectively. Meanwhile, the reducing gas containing hydrogen (reducing substance) supplied from the reducing gas supply unit 2 passes through gas line GL2, gas switching unit 3, and gas lines GL3a and GL3b, and is supplied to the first reactors 4a and 4b, respectively.

[0028] The first reactors 4a and 4b are capable of producing carbon monoxide from carbon dioxide (converting carbon dioxide into carbon monoxide). Each of the first reactors 4a and 4b, as shown in Figure 2, is a multi-tube reactor (fixed-bed reactor) comprising a plurality of tubes 41 each filled (contained) with a reducing agent (reducing agent) 4R, and a housing 42 that houses the plurality of tubes 41 in an internal space 43. Such a multi-tube reactor ensures sufficient opportunities for contact between the reducing agent 4R and the exhaust gas and reducing gas. As a result, the efficiency of converting carbon dioxide to carbon monoxide can be increased. Furthermore, the first reactors 4a and 4b can also be constructed by omitting the tubular body 41 and filling the internal space 43 of the housing 42 with the reducing agent 4R (i.e., a simple reactor). The reducing agent 4R in this embodiment is preferably in the form of particulate matter (granules), flakes, pellets, etc. Using a reducing agent 4R in such a form can increase the filling efficiency into the pipe 41 and further increase the contact area with the gas supplied into the pipe 41.

[0029] When the reducing agent 4R is in particulate form, its volume-average particle size is not particularly limited, but is preferably 1 mm to 50 mm, and more preferably 1 mm to 30 mm. In this case, the contact area between the reducing agent 4R and the exhaust gas (carbon dioxide) can be further increased, and the efficiency of converting carbon dioxide to carbon monoxide can be further improved. Similarly, the regeneration (reduction) of the reducing agent 4R with a reducing gas containing reducing substances can be performed more efficiently. Since the particulate reducing agent 4R has a higher degree of sphericity, it is preferable that the molded product is manufactured by tumbling granulation.

[0030] Furthermore, the reducing agent 4R may be supported on a carrier. The constituent material of the support can be any material that is not easily modified by contact with exhaust gas (oxidizing gas) or reaction conditions. Examples include carbon materials (graphite, graphene, carbon black, carbon nanotubes, activated carbon, etc.), carbides such as Mo2C, zeolites, montmorillonite, oxides such as ZrO2, TiO2, V2O5, MgO, CeO2, Al2O3, SiO2, and composite oxides containing these.

[0031] Among these, zeolite, montmorillonite, ZrO2, TiO2, V2O5, MgO, Al2O3, SiO2, and composite oxides containing these are preferred as constituent materials for the support. Supports composed of such materials are preferred because they do not adversely affect the reaction of reducing agent 4R and have excellent ability to support reducing agent 4R. Here, the support does not participate in the reaction of reducing agent 4R, but simply supports (holds) the reducing agent 4R. One example of such a configuration is one in which at least a portion of the surface of the carrier is coated with a reducing agent 4R.

[0032] The reducing agent 4R comprises at least one of a metal and a metal oxide (an oxygen carrier possessing oxygen ion conductivity). The at least one of the metal and the metal oxide is not particularly limited as long as it can reduce carbon dioxide, but it is preferably composed of at least one selected from metal elements belonging to groups 3 to 13, more preferably at least one selected from metal elements belonging to groups 3 to 12, even more preferably at least one of lanthanum, titanium, vanadium, iron, copper, zinc, nickel, manganese, chromium, and cerium, and metal oxides or composite metal oxides containing iron and / or cerium are particularly preferred. These metal oxides are useful because they have particularly good efficiency in converting carbon dioxide to carbon monoxide. Here, "metal" includes elemental metals consisting of only one of the above-mentioned metal elements, and alloys consisting of two or more of the above-mentioned metal elements.

[0033] Furthermore, in each of the first reactors 4a and 4b, the reducing agent 4R (at least one of a metal and a metal oxide) itself may be used to create the tubular body (cylindrical molded body) 41. In addition, the reducing agent 4R may be used to create molded bodies such as blocks or grids (e.g., mesh or honeycomb) and placed inside the housing 42. In these cases, the reducing agent 4R as a packing material may be omitted or used in combination.

[0034] Among these, a configuration in which a mesh structure is made from the reducing agent 4R and placed inside the housing 42 is preferred. In this configuration, it is possible to prevent an increase in the resistance to the passage of exhaust gas and reducing gas in each of the first reactors 4a and 4b while ensuring sufficient opportunities for contact between the reducing agent 4R and the exhaust gas and reducing gas. The volumes of the two first reactors 4a and 4b are set to be approximately equal to each other and are adjusted as appropriate according to the amount of exhaust gas to be processed (size of exhaust gas supply unit 1 and size of manufacturing equipment 100). In addition, the volumes of the two first reactors 4a and 4b may be made different depending on the type of exhaust gas and reducing gas, the performance of the reducing agent 4R, etc.

[0035] With the above configuration, by switching the gas line (flow path) in the gas switching unit 3, for example, exhaust gas can be supplied to the first reactor 4a containing the reducing agent 4R before oxidation via gas line GL3a, and reducing gas can be supplied to the first reactor 4b containing the reducing agent 4R after oxidation via gas line GL3b. At this time, the reaction shown in equation 1 below proceeds in the first reactor 4a, and the reaction shown in equation 2 below proceeds in the first reactor 4b.

[0036] In addition, in the following equations 1 and 2, the reducing agent 4R is iron oxide (FeO x-1 This is an example of a case where ) is included. Formula 1: CO2+ FeO x-1 → CO + FeO x Formula 2: H2+ FeO x → H2O + FeO x-1 Subsequently, by switching the gas line in the opposite direction at the gas switching section 3, the reaction of formula 2 can be carried out in the first reactor 4a, and the reaction of formula 1 can be carried out in the first reactor 4b. In other words, exhaust gas (raw material gas) and reducing gas are supplied to the first reactor 4a and the first reactor 4b in a switching manner.

[0037] Furthermore, the reactions shown in Equations 1 and 2 above are both endothermic reactions. For this reason, it is preferable that the manufacturing apparatus 100 (carbon material manufacturing system 10) further includes a reducing agent heating unit (not shown in Figure 1) that heats the reducing agent 4R when the reducing agent 4R is brought into contact with exhaust gas or reducing gas (i.e., when the exhaust gas or reducing gas reacts with the reducing agent 4R). By providing such a reducing agent heating section, the temperature in the reaction between the exhaust gas or reducing gas and the reducing agent 4R can be maintained at a high temperature, thereby effectively preventing or suppressing a decrease in the efficiency of carbon dioxide conversion to carbon monoxide, and further promoting the regeneration of the reducing agent 4R by the reducing gas.

[0038] However, depending on the type of reducing agent 4R, the reactions shown in formulas 1 and 2 above may be exothermic. In this case, it is preferable that the manufacturing apparatus 100 has a reducing agent cooling section for cooling the reducing agent 4R instead of a reducing agent heating section. By providing such a reducing agent cooling section, it is possible to suitably prevent the deterioration of the reducing agent 4R during the reaction between the exhaust gas or reducing gas and the reducing agent 4R, suitably prevent or suppress the decrease in the conversion efficiency of carbon dioxide to carbon monoxide, and further promote the regeneration of the reducing agent 4R by the reducing gas. In other words, it is preferable that the manufacturing apparatus 100 be equipped with a reducing agent temperature control unit that adjusts the temperature of the reducing agent 4R depending on the type of reducing agent 4R (exothermic reaction or endothermic reaction).

[0039] Here, the conversion rate of carbon dioxide to carbon monoxide in the first reactors 4a and 4b is preferably 70% or more, more preferably 85% or more, and even more preferably 95% or more. The upper limit of the conversion rate of carbon dioxide to carbon monoxide is usually around 98%. Such conversion rates can be set by adjusting the type of reducing agent 4R used, the concentration of carbon dioxide in the exhaust gas, the type of reducing substance, the concentration of reducing substance in the reducing gas, the temperatures of the first reactors 4a and 4b, the flow rates (velocities) of the exhaust gas and reducing gas to the first reactors 4a and 4b, and the timing of the switching between the exhaust gas and the reducing gas.

[0040] Gas lines GL4a and GL4b are connected to the outlet ports of the first reactors 4a and 4b, respectively, and these lines merge at the gas confluence J to form gas line GL4. Valves (not shown) are provided in gas lines GL4a and GL4b as needed. For example, by adjusting the valve opening, the passage rates of the exhaust gas and reducing gas passing through the first reactors 4a and 4b (i.e., the processing rate of the exhaust gas by the reducing agent 4R and the processing rate of the reducing agent 4R by the reducing gas) can be set.

[0041] Gas line GL4 is connected to the inlet port of the second reactor 5. In other words, the second reactor (second reaction section) 5 is connected to the first reactors 4a and 4b (first reaction sections) via gas lines GL4a, GL4b, and gas line GL4. This allows the exhaust gas from the first reactors 4a and 4b to be supplied to the second reactor 5 as a mixed gas. The second reactor 5 is capable of producing (converting) carbon materials from carbon monoxide. Specifically, in the second reactor 5, carbon materials are produced from carbon monoxide contained in the mixed gas by the so-called Boudoir reaction shown in Equation 3 below. Equation 3: 2CO ⇔ C + CO2 The second reactor 5 can be a reactor similar to the one described for the first reactors 4a and 4b. In this case, the tube 41 is filled with one or more of the following catalysts. Examples of catalysts include: (1) tungsten, rhenium, osmium, tantalum, molybdenum, niobium, iridium, ruthenium, hafnium, technetium, rhodium, vanadium, chromium, zirconium, platinum, thorium, lutetium, titanium, palladium, protactinium, thulium, scandium, iron, yttrium, erbium, cobalt, holmium, nickel, dysprosium, terbium, curium, cadrinium, beryllium, manganese, americium, promethium, uranium, copper, samarium, gold, actinium, neodymium, berkelium, silver, germanium, praseodymium, lanthanum, californium, calcium, europium, ytterbium, Examples include: (1) elements (elements or complexes) containing cerium, strontium, barium, radium, aluminum, magnesium, plutonium, neptinium, antimony, zinc, lead, cadmium, thallium, bismuth, polonium, tin, lithium, indium, sodium, potassium, rubidium, gallium, cesium, silicon, or tellurium; (2) sulfides, borides, oxides, chlorides, hydroxides, nitrides, and organometallic compounds of the above elements; (3) mixtures of either (1) or (2) above with sulfur and / or sulfides (including organosulfur compounds); (4) mixtures of either (1) or (2) above with boron and / or borides (including organoboron compounds), etc.

[0042] A pressure adjustment section 8 is provided in the middle of the gas line GL4 to increase the pressure of the mixed gas passing through the gas line GL4. By increasing the pressure of the mixed gas, the equilibrium of the reaction described in Equation 3 can be shifted (tilted) to the right, and thus the efficiency of carbon material production can be further increased. Specifically, the pressure of the mixed gas after pressurization by the pressure adjustment unit 8 is preferably 0.1 MPaG or higher, more preferably 0.1 MPaG to 10 MPaG, even more preferably 0.1 MPaG to 5 MPaG, particularly preferably 0.1 MPaG to 3 MPaG, and most preferably 0.1 MPaG to 2 MPaG. The lower limit of the pressure may be 0.2 MPaG or higher, or 0.5 MPaG or higher. By adjusting the pressure of the mixed gas, the efficiency of carbon material production can be further increased. Such a pressure regulating unit 8 may include a valve, a pressure regulating bubble, etc. The pressure regulating unit 8 may be provided as needed, or it may be omitted.

[0043] Furthermore, a cooler and a gas-liquid separator (not shown) may be installed in the middle of the gas line GL4 to cool the mixed gas. A cooler generates condensed water (liquid) by cooling the gas mixture. Such a cooler may include a jacketed cooling device with a jacket arranged around the piping to allow the refrigerant to pass through, a multi-tube cooling device with the same configuration as the first reactors 4a and 4b (see Figure 2) in which a mixed gas passes through the tubes and a refrigerant passes around the tubes, an air fin cooler, and the like.

[0044] A gas-liquid separator separates condensate, which is produced when a gas mixture is cooled in a cooler, from the gas mixture. A benefit of this separation is that the condensate can dissolve and remove unwanted gas components (especially carbon dioxide) remaining in the gas mixture. A gas-liquid separator can be constructed from, for example, a simple container, a swirling flow separator, a centrifugal separator, a surface tension separator, etc. Among these, a gas-liquid separator is preferably constructed from a simple container because it is simple in structure and inexpensive. In this case, a filter that allows the passage of gas but prevents the passage of liquid may be placed at the gas-liquid interface inside the container.

[0045] As described above, by removing water and unwanted gas components from the mixed gas, a mixed gas with a higher concentration of carbon monoxide can be supplied to the second reactor 5. Therefore, the decrease in the conversion efficiency of carbon monoxide to carbon materials can be prevented or suppressed, and the amount produced can be increased.

[0046] The second reaction temperature in the second reactor (second reaction section) 5 is preferably lower than the first reaction temperature in the first reactors 4a and 4b (first reaction section 4). In this case, the reaction heat from the first reactors 4a and 4b can be effectively utilized in the second reactor 5. Specifically, the second reaction temperature is preferably 850°C or lower, more preferably 600°C or lower, and even more preferably 400°C or lower. This improves the efficiency of carbon material production while also increasing the efficiency of heat utilization.

[0047] Gas line GL5 is connected to the outlet port of the second reactor 5. A product gas discharge section 6, which discharges the product gas to the outside of the manufacturing apparatus 100, is connected to the opposite end of the gas line GL5 from the second reactor 5.

[0048] Next, we will explain how to use the carbon material manufacturing system 10 (method for manufacturing carbon materials). [1] First, the gas line (flow path) is switched in the gas switching section 3 to connect the exhaust gas supply section 1 with the first reactor 4a, and the reducing gas supply section 2 with the first reactor 4b. [2] Next, in this state, exhaust gas is supplied from the exhaust gas supply unit 1 to the first reactor 4a via the gas line GL1. In the first reactor 4a, the reducing agent 4R reduces carbon dioxide to carbon monoxide by contact with the exhaust gas (raw material gas containing carbon dioxide). At this time, the reducing agent 4R is brought into an oxidized state by contact with carbon dioxide.

[0049] In the above step [2], the temperature of the first reactor 4a (exhaust gas, reducing agent 4R) (first reaction temperature) is preferably 500°C or higher, more preferably 650°C to 1100°C, and even more preferably 700°C to 1000°C. Furthermore, the pressure of the first reactor 4a (exhaust gas, reducing agent 4R) (first reaction pressure) is preferably less than 1 MPaG, more preferably 0.9 MPaG or less, and even more preferably 0.2 MPaG or more and 0.8 MPaG or less. By setting the reaction conditions within the above range, for example, it is possible to prevent or suppress the rapid temperature drop of the reducing agent 4R due to the endothermic reaction when converting carbon dioxide to carbon monoxide, thereby allowing the reduction reaction of carbon dioxide in the first reactor 4a to proceed more smoothly.

[0050] [3] In parallel with the above steps [1] to [2], water (reducing gas raw material) is supplied from the tank to the hydrogen generator (reducing gas supply unit 2) to generate hydrogen from the water. [4] Next, a reducing gas containing hydrogen is supplied from the hydrogen generator to the first reactor 4b via the gas line GL2. In the first reactor 4b, the reducing agent 4R in an oxidized state is reduced (regenerated) by contact with the reducing gas (hydrogen). Water is produced at this time. In this case, the hydrogen may be produced on-site, or it may be purified at another location and supplied from a pipeline or cylinder. The production method of the hydrogen is not restricted as long as it is green hydrogen. Also, green hydrogen may be used for only a portion of the hydrogen.

[0051] In step [4] described above, the temperature (reaction temperature) of the first reactor 4b (reducing gas, reducing agent 4R) is preferably 500°C or higher, more preferably 650°C to 1100°C, and even more preferably 700°C to 1000°C. Furthermore, the pressure of the first reactor 4b (reducing gas, reducing agent 4R) (first reaction pressure) is preferably less than 1 MPaG, more preferably 0.9 MPaG or less, and even more preferably 0.2 MPaG or more and 0.8 MPaG or less. By setting the reaction conditions within the above range, for example, it is possible to prevent or suppress the rapid temperature drop of the reducing agent 4R due to the endothermic reaction when reducing (regenerating) the oxidized reducing agent 4R, thereby allowing the reduction reaction of the reducing agent 4R in the first reactor 4b to proceed more smoothly. In this embodiment, steps [2] to [4] above constitute a first production step in which carbon monoxide is produced from carbon dioxide.

[0052] [5] Next, the gases that have passed through the first reactors 4a and 4b merge to form a mixed gas. At this point, the temperature of the mixed gas is usually between 200°C and 1000°C. If the temperature of the mixed gas at this point is within the above range, it means that the temperature inside the first reactors 4a and 4b is being maintained at a sufficiently high temperature, and it can be determined that the conversion of carbon dioxide to carbon monoxide by the reducing agent 4R and the reduction of the reducing agent 4R by the reducing gas are proceeding efficiently.

[0053] [6] Next, the mixed gas is passed through the gas line GL4 to the pressure adjustment section 8. At this time, the pressure of the mixed gas increases. In this embodiment, step [6] constitutes a pressure adjustment step that increases the pressure of the gas (mixed gas) produced in the first generation step. [7] Next, the mixed gas that has passed through the pressure adjustment section 8 is supplied to the second reactor 5. In the second reactor 5, carbon monoxide is converted into carbon material. In this embodiment, step [7] constitutes a second production step in which a carbon material is produced from carbon monoxide. The generated gas (mixed gas) containing carbon material is then discharged from the generated gas discharge section 6 to the outside of the manufacturing apparatus 100 via the gas line GL5 and used for the next process.

[0054] <<Second Embodiment>> Next, a second embodiment of the carbon material manufacturing system of the present invention will be described. Figure 3 is a schematic diagram showing the configuration of a second embodiment of the carbon material manufacturing system of the present invention. The carbon material manufacturing system 10 of the second embodiment will be described below, focusing on the differences from the carbon material manufacturing system 10 of the first embodiment, and similar matters will be omitted from the explanation.

[0055] In the second embodiment, gas lines GL6a and GL6b branch off from gas lines GL4a and GL4b midway and merge at gas confluence J1 to form gas line GL6. A switching valve is also provided at the branching point between gas lines GL4a and GL4b and gas lines GL6a and GL6b. The exhaust gas discharged from the first reactors 4a and 4b passes through gas lines GL4a, GL4b, and GL4 and is supplied to the second reactor 5. The reducing gas discharged from the first reactors 4a and 4b passes through gas lines GL6a, GL6b, and GL6, and after, for example, water is removed, it is returned to the reducing gas supply unit 2.

[0056] In other words, in this embodiment, the exhaust gas (raw material gas) after passing through the first reactors 4a and 4b is configured to separate from the reduced gas after passing through the first reactors 4a and 4b. The exhaust gas that has passed through the first reactors 4a and 4b is then supplied to the second reactor 5 without merging with the reducing gas that has passed through the first reactors 4a and 4b. With this configuration, exhaust gas with reduced water contamination can be supplied to the second reactor 5. Therefore, a decrease in the efficiency of carbon monoxide conversion to carbon materials can be prevented or suppressed, and the amount produced can be increased.

[0057] <<Third Embodiment>> Next, a third embodiment of the carbon material manufacturing system of the present invention will be described. Figure 4 is a schematic diagram showing the configuration of a third embodiment of the carbon material manufacturing system of the present invention. The carbon material manufacturing system 10 of the third embodiment will be described below, focusing on the differences from the carbon material manufacturing system 10 of the first embodiment, and similar matters will be omitted from the explanation. The carbon material manufacturing system 10 of the third embodiment includes a recovery unit 9 instead of a generated gas discharge unit 6.

[0058] The recovery unit 9 recovers carbon material from the gas (product gas) generated in the second reactor 5. This recovery unit 9 can be configured by combining one or more of the following: an elutriation device, a centrifugal separator, an electrostatic precipitator, and a filter device. The recovery unit 9 is connected to the gas line GL1 via the return gas line GL7. As described above, in the second reactor 5, a product gas containing carbon dioxide in addition to carbon material is generated from carbon monoxide. Therefore, the generated gas is separated into carbon material and generated gas containing carbon dioxide by passing through the recovery unit 9.

[0059] Then, the generated gas after the carbon material has been recovered in the recovery section 9 is returned to the first reactors 4a and 4b via the return gas line GL7 and the gas line GL1. With this configuration, the generated gas after passing through the recovery unit 9 can be effectively utilized without being discarded. In particular, since the generated gas after passing through the recovery unit 9 has a sufficiently high concentration of carbon dioxide, even when mixed with exhaust gas, it is possible to effectively prevent a decrease in the conversion efficiency of carbon dioxide to carbon monoxide in the first reactors 4a and 4b.

[0060] In the first reactors 4a and 4b described above, when the exhaust gas (raw material gas) comes into contact with the reducing agent 4R, carbon monoxide is produced by the reduction reaction of carbon dioxide. At the same time, at least a portion of the oxygen element released from carbon dioxide is captured by the reducing agent 4R, and then, when the reducing gas comes into contact with the reducing agent 4R, it is transferred to hydrogen (reducing substance), and water (oxide of the reducing substance) is produced. In other words, in the first reactors 4a and 4b, at least a portion of the oxygen element can be separated within the carbon dioxide reduction reaction system (reaction field). A reactor capable of separating at least a portion of the oxygen element within the carbon dioxide reduction reaction system can employ the configuration shown in Figure 5.

[0061] <<Fourth Embodiment>> Next, a fourth embodiment of the carbon material manufacturing system of the present invention will be described. Figure 5 is a schematic diagram showing the configuration of the first reactor in the fourth embodiment. The carbon material manufacturing system 10 of the fourth embodiment will be described below, focusing on the differences from the carbon material manufacturing systems 10 of the first to third embodiments, and similar matters will be omitted from the explanation.

[0062] The first reaction section 4 shown in Figure 5 consists of a reactor (also called a reaction cell, electrolytic cell, or electrochemical cell) that electrochemically carries out the reduction reaction of carbon dioxide. The first reaction unit 4 includes a housing 42, a cathode 45, an anode 46, and a solid electrolyte layer 47 provided within the housing 42, and a power supply 48 electrically connected to the cathode 45 and anode 46. In this configuration, the space within the housing 42 is divided into left and right sections by a laminate of the cathode (reducing agent) 45, the anode 46, and the solid electrolyte layer 47.

[0063] The housing 42 includes a cathode-side inlet port 421a, a cathode-side outlet port 421b, an anode-side inlet port 422a, and an anode-side outlet port 422b. The cathode-side inlet port 421a and the cathode-side outlet port 421b communicate with the cathode chamber in the left-side space within the housing 42, while the anode-side inlet port 422a and the anode-side outlet port 422b communicate with the anode chamber in the right-side space within the housing 42.

[0064] The cathode 45 and anode 46 are each composed of a conductive carrier and a catalyst supported on this carrier. The carrier can be made of carbon materials such as carbon fiber fabrics (carbon cloth, carbon felt, etc.) or carbon paper. Examples of catalysts include platinum group metals such as platinum, ruthenium, rhodium, palladium, osmium, and iridium; transition metals such as gold; alloys of these metals; and alloys of these metals with other metals.

[0065] The solid electrolyte layer 47 can be composed of, for example, a fluorine-based polymer film having sulfonic acid groups (such as Nafion®), a sulfo-based ion exchange resin film, or the like. It is preferable to use a power source 48 that generates electricity as a renewable energy source. This makes it possible to further improve the energy efficiency in the production of the generated gas containing carbon valuables.

[0066] In this first reaction unit 4, when exhaust gas (carbon dioxide and water) is supplied from the cathode-side inlet port 421a, the electrons supplied from the power supply 48 interact with the catalyst to reduce carbon dioxide and water, producing carbon monoxide and hydrogen, as well as oxygen ions. Carbon monoxide and hydrogen are discharged from the cathode-side outlet port 421b into the gas line (gas line GL4), and oxygen ions diffuse through the solid electrolyte layer 47 toward the anode 46. Upon reaching the anode 46, the oxygen ions are converted back into oxygen by having electrons removed and are discharged from the anode-side outlet port 422b.

[0067] In this configuration, carbon monoxide and hydrogen discharged from the cathode-side outlet port 421b are supplied to the second reactor 5. In this case, a hydrogen removal section may be provided in the middle of the gas line GL4.

[0068] Furthermore, the carbon material manufacturing system 10 may be configured such that the reaction of the following formula 4 is carried out in the first reaction section 4, and the reaction of the following formula 5 is carried out in the second reaction section 5. Formula 4: CO2+ H2→ CO + H2O Equation 5: CO + H2→ C + H2O In other words, the Bosch reaction can be carried out through the first reaction section 4 and the second reaction section 5. Note that the reactions of Equation 4 and Equation 5 may occur simultaneously.

[0069] In this case, the first reaction section 4 and the second reaction section 5 can use the same type of reaction apparatus (heat exchanger) as described for the first reactors 4a and 4b, respectively, or they can use plate reactors, plate-fin reactors, helical reactors, etc. Furthermore, the usable catalyst preferably contains at least one metal element selected from groups 2 to 15, more preferably at least one metal element selected from groups 5 to 10, and even more preferably at least one of nickel, molybdenum, chromium, cobalt, tungsten, vanadium, ruthenium, iridium, iron, etc.

[0070] The first reaction temperature in the first reaction section 4 is preferably 400°C to 1200°C, more preferably 500°C to 1000°C, even more preferably 600°C to 800°C, and particularly preferably 680°C to 700°C. The first reaction pressure in the first reaction section 4 is preferably 0.1 MPaG or more and 5 MPaG or less, more preferably 0.2 MPaG or more and 4.5 MPaG or less, even more preferably 0.25 MPaG or more and 4 MPaG or less, and particularly preferably 0.3 MPaG or more and 3.5 MPaG or less.

[0071] Furthermore, the second reaction temperature in the second reaction section 5 is preferably 400°C or more and 1000°C or less, more preferably 450°C or more and 900°C or less, even more preferably 500°C or more and 800°C or less, and particularly preferably 550°C or more and 700°C or less. The second reaction pressure in the second reaction section 5 is preferably 0.1 MPaG or more and 5 MPaG or less, more preferably 0.2 MPaG or more and 4.5 MPaG or less, even more preferably 0.25 MPaG or more and 4 MPaG or less, and particularly preferably 0.3 MPaG or more and 3.5 MPaG or less.

[0072] <<Fifth Embodiment>> Next, a fifth embodiment of the carbon material manufacturing system of the present invention will be described. Figure 6 is a schematic diagram showing the configuration of a fifth embodiment of the carbon material manufacturing system of the present invention. The carbon material manufacturing system 10 of the fifth embodiment will be described below, focusing on the differences from the carbon material manufacturing systems 10 of the first to fourth embodiments, and similar matters will be omitted from the explanation.

[0073] The carbon material manufacturing system 10 shown in Figure 6 is a manufacturing system for manufacturing carbon materials and comprises a manufacturing apparatus 100, a blast furnace (gas supply unit) 101 connected to the manufacturing apparatus 100 and supplied with exhaust gas (raw material gas containing carbon dioxide), and a reducing gas supply unit 2 that supplies reducing gas. In this specification, the upstream side with respect to the direction of gas flow will also be simply referred to as the "upstream side," and the downstream side will also be simply referred to as the "downstream side." Furthermore, in this specification, "smelting," which is performed to increase the purity of metals, is also included in "smelting."

[0074] In this embodiment, the gas supply unit is described as a blast furnace (a furnace related to a smelter) 101, but the gas supply unit may be other furnaces related to a smelter. Preferred other furnaces include shaft furnaces, converters, electric furnaces, etc. Furthermore, the gas supply unit can have the same configuration as the exhaust gas supply unit 1 described above. The blast furnace (smelting furnace) 101 is connected to the gas switching unit 3 via the gas line GL1, and the reducing gas supply unit 2 is connected to the gas switching unit 3 via the gas line GL2. Therefore, in this embodiment, the exhaust gas supply unit 1 in the first to fourth embodiments can be read as the blast furnace 101.

[0075] Gas line GL5 is connected to the outlet port of the second reactor 5. In this embodiment, a recovery unit 9 is connected to the end of the gas line GL5 opposite the second reactor 5, instead of the generated gas discharge unit 6. The recovery unit 9 recovers carbon material from the gas (product gas) generated in the second reactor 5. This recovery unit 9 can be configured by combining one or more of the following: an elutriation device, a centrifugal separator, an electrostatic precipitator, and a filter device. The recovery unit 9 is connected to the gas line GL1 via the return gas line GL8. As described above, in the second reactor 5, a product gas containing carbon dioxide in addition to carbon material is generated from carbon monoxide. Therefore, the generated gas is separated into carbon material and generated gas containing carbon dioxide by passing through the recovery unit 9.

[0076] Then, the generated gas after the carbon material has been recovered in the recovery section 9 is returned to the first reactors 4a and 4b via the return gas line GL8 and gas line GL1. With this configuration, the generated gas after passing through the recovery unit 9 can be effectively utilized without being discarded. As a result, carbon dioxide emissions can be reduced, and a circular economy (a society that recycles materials) can be realized. In particular, since the generated gas after passing through the recovery unit 9 has a sufficiently high concentration of carbon dioxide, even when mixed with exhaust gas, it is possible to effectively prevent a decrease in the conversion efficiency of carbon dioxide to carbon monoxide in the first reactors 4a and 4b.

[0077] Furthermore, the above configuration produces a carbon material with an extremely low solid impurity content. Specifically, the solid impurity content in the carbon material is 1% by mass or less, preferably 0.1% by mass or less, and more preferably 0.01% by mass or less. The lower limit of the solid impurity content in the carbon material is not particularly limited, but is usually 0.001% by mass or more. Carbon materials with such a low solid impurity content can be used in various electronic devices, molded products, etc., without causing a deterioration in their properties. Examples of solid impurities include at least one of the following: copper, zinc, iron, nickel, aluminum, chromium, and alloys containing these.

[0078] Such carbon materials are suitably used in at least one of the following applications: secondary battery materials (e.g., negative electrode active material, conductive additive for negative or positive electrode), tire fillers, colorants for resin or rubber materials, UV protection and absorption materials, fuel cell electrode materials, and heat dissipation materials. For example, using carbon materials as the negative electrode active material in an ion-based secondary battery can prevent short-circuits in the battery and reduce the charge-discharge characteristics. Furthermore, for example, using carbon materials as fillers for tires can more effectively suppress the deterioration of tire elasticity and flexibility over time.

[0079] Next, we will explain how to use the carbon material manufacturing system 10 (method for manufacturing carbon materials).

[11] First, perform the same steps as in step [1] above.

[12] Next, the same process as in step [2] above is carried out.

[0080] In step

[12] above, the temperature of the first reactor 4a (exhaust gas, reducing agent 4R) (first reaction temperature) is preferably set in the same way as in step [2] above. Furthermore, the pressure of the first reactor 4a (exhaust gas, reducing agent 4R) (first reaction pressure) is preferably set in the same manner as in step [2] above.

[0081]

[13] Perform the same steps as in step [3] above.

[14] Perform the same steps as in step [4] above.

[0082] In step

[14] above, the temperature (reaction temperature) of the first reactor 4b (reducing gas, reducing agent 4R) is preferably set in the same way as in step [4] above. Furthermore, the pressure of the first reactor 4b (reducing gas, reducing agent 4R) (first reaction pressure) is preferably set in the same manner as in step [4] above.

[0083]

[15] Next, the same process as in the above process [5] is carried out.

[0084]

[16] Next, the same process as in the above process [6] is carried out.

[17] Next, the same process as in the above process [7] is carried out. In this embodiment, the generated gas (mixed gas) containing carbon material is discharged to the recovery unit 9 via the gas line GL5.

[0085]

[18] Next, in the recovery unit 9, the carbon material is separated and recovered from the generated gas containing the carbon material. As described above, the content of solid impurities in the carbon material is 1% by mass or less.

[19] Next, the product gas after the carbon material has been recovered in the recovery section 9 is returned to the first reactors 4a and 4b via the return gas line GL8 and the gas line GL1. This exhaust gas goes through the above processes

[11] to

[17] , and carbon material is generated again.

[0086] <<Sixth Embodiment>> Next, a sixth embodiment of the carbon material manufacturing system of the present invention will be described. Figure 7 is a schematic diagram showing the configuration of the sixth embodiment of the carbon material manufacturing system of the present invention. The carbon material manufacturing system 10 of the sixth embodiment will be described below, focusing on the differences from the carbon material manufacturing system 10 of the fifth embodiment, and similar matters will be omitted from the explanation.

[0087] In the sixth embodiment, gas lines GL6a and GL6b branch off from gas lines GL4a and GL4b midway and merge at gas confluence J1 to form gas line GL6. A switching valve is also provided at the branching point between gas lines GL4a and GL4b and gas lines GL6a and GL6b. The exhaust gas discharged from the first reactors 4a and 4b passes through gas lines GL4a, GL4b, and GL4 and is supplied to the second reactor 5. The reducing gas discharged from the first reactors 4a and 4b passes through gas lines GL6a, GL6b, and GL6, and after, for example, water is removed, it is returned to the reducing gas supply unit 2.

[0088] In other words, in this embodiment, the exhaust gas after passing through the first reactors 4a and 4b is separated from the reduced gas after passing through the first reactors 4a and 4b. The exhaust gas that has passed through the first reactors 4a and 4b is then supplied to the second reactor 5 without merging with the reducing gas that has passed through the first reactors 4a and 4b. With this configuration, exhaust gas with reduced water contamination can be supplied to the second reactor 5. Therefore, a decrease in the efficiency of carbon monoxide conversion to carbon materials can be prevented or suppressed, and the amount produced can be increased.

[0089] <<Seventh Embodiment>> Next, a seventh embodiment of the carbon material manufacturing system of the present invention will be described. Figure 8 is a schematic diagram showing the configuration of the seventh embodiment of the carbon material manufacturing system of the present invention. The carbon material manufacturing system 10 of the seventh embodiment will be described below, focusing on the differences from the carbon material manufacturing system 10 of the fifth embodiment, and similar matters will be omitted from the explanation. The carbon material manufacturing system 10 of the seventh embodiment includes a separation unit 11 for separating carbon dioxide from exhaust gas, located in the middle of the gas line GL1 (upstream of the first reaction unit 4).

[0090] By passing the exhaust gas through the separation section 11, the concentration of carbon dioxide in the exhaust gas can be increased. This makes it possible to further improve the efficiency of carbon dioxide conversion to carbon monoxide in the first reactors 4a and 4b. Methods for separating carbon dioxide from exhaust gas include, for example, cryogenic separators, pressure swing adsorption (PSA) separators, membrane separators, temperature swing adsorption (TSA) separators, amine absorption separators, and amine adsorption separators. One of these can be used alone or in combination of two or more.

[0091] In the fifth to seventh embodiments described above, in the first reactors 4a and 4b, when exhaust gas comes into contact with the reducing agent 4R, carbon monoxide is produced by the reduction reaction of carbon dioxide, and at least a portion of the oxygen element released from carbon dioxide is captured by the reducing agent 4R. Subsequently, when the reducing gas comes into contact with the reducing agent 4R, it is transferred to hydrogen (reducing substance), and water (oxide of the reducing substance) is produced. In other words, in the first reactors 4a and 4b, at least a portion of the oxygen element can be separated within the carbon dioxide reduction reaction system (reaction field). A reactor capable of separating at least a portion of the oxygen element within the carbon dioxide reduction reaction system can employ the configuration shown in Figure 5.

[0092] <Carbon cycle system> Secondly, the carbon recycling system of the present invention will be described. <<First Embodiment>> First, a first embodiment of the carbon recycling system of the present invention will be described. Figure 9 is a schematic diagram showing the configuration of the first embodiment of the carbon recycling system of the present invention. The carbon recycling system 1000 will be described below, focusing on the differences from the carbon material manufacturing system 10 of the first to fourth embodiments, and similar matters will be omitted from the explanation.

[0093] The carbon cycle system 1000 shown in Figure 9 is a system for producing (smelting) the target metal, and includes a blast furnace (melting furnace) 101 that supplies exhaust gas (gas containing carbon dioxide) and a reducing gas supply unit 2 that supplies reducing gas. In this specification, the upstream side with respect to the direction of gas flow will also be simply referred to as the "upstream side," and the downstream side will also be simply referred to as the "downstream side." Furthermore, in this specification, "smelting," which is performed to increase the purity of metals, is also included in "smelting."

[0094] In this embodiment, the configuration utilizes exhaust gas discharged from the blast furnace 101, but other furnaces attached to a steel mill or smelter may also be used. Preferred other furnaces include shaft furnaces, converters, and electric furnaces. In each furnace, exhaust gas is generated during the melting and refining of the contents. The exhaust gas usually contains carbon dioxide and carbon monoxide, as well as other gaseous components such as nitrogen, oxygen, water vapor, and methane. The exhaust gas from blast furnace 101 (blast furnace gas) is, for example, the gas generated when producing pig iron in blast furnace 101, and contains carbon dioxide at a ratio of 5% to 45% by volume, nitrogen at a ratio of 55% to 60% by volume, carbon monoxide at a ratio of 10% to 40% by volume, and hydrogen at a ratio of 1% to 10% by volume.

[0095] Furthermore, the exhaust gas from the converter (converter gas) is a gas generated during the production of steel in the converter, and contains carbon dioxide at a concentration of 15% to 20% by volume, carbon monoxide at a concentration of 50% to 80% by volume, nitrogen at a concentration of 15% to 25% by volume, and hydrogen at a concentration of 1% to 5% by volume. By using these exhaust gases, carbon dioxide that was previously released into the atmosphere can be effectively utilized, reducing the burden on the environment and improving the degree of material cycles. Furthermore, blast furnace gas and converter gas may be used as untreated gas discharged from the furnace, or treated gas may be used after treatment to remove, for example, carbon monoxide. In this specification, all of the above gases are referred to as exhaust gas.

[0096] The carbon circulation system 1000 of this embodiment further comprises a gas switching unit 3, two first reactors 4a and 4b (first reaction unit 4), and one second reactor (second reaction unit) 5. The blast furnace (smelting furnace) 101 is connected to the gas switching unit 3 via the gas line GL1, and the reducing gas supply unit 2 is connected to the gas switching unit 3 via the gas line GL2. Therefore, in this embodiment, the exhaust gas supply unit 1 in the carbon material manufacturing system 10 can be read as the blast furnace 101.

[0097] In this embodiment, it is preferable that the second reaction temperature in the second reactor (second reaction section) 5 is lower than the first reaction temperature in the first reactors 4a and 4b (first reaction section 4). In this case, the reaction heat in the first reactors 4a and 4b can be effectively utilized in the second reactor 5. Specifically, the second reaction temperature is preferably 850°C or lower, more preferably 800°C or lower, and even more preferably 750°C or lower. This improves the efficiency of carbon material production while also increasing the efficiency of heat utilization. The lower limit of the second reaction temperature is usually 600°C or higher.

[0098] Gas line GL5 is connected to the outlet port of the second reactor 5. A product gas supply unit 60 is connected to the opposite end of the gas line GL5 from the second reactor 5. This generated gas supply unit 60 is configured to supply generated gas (carbon material) to the ore, which is the raw material for smelting, via the gas line GL70. The ore mixed with the carbon material (i.e., the ore together with the carbon material) is then supplied to the blast furnace (melting furnace) 101 for refining. In other words, in this embodiment, the blast furnace 101 used for refining and the blast furnace 101 used for recovering exhaust gas are the same. With this configuration, carbon dioxide can be used for refining without releasing it into the external environment, and this can contribute to the realization of a circular economy (a society that recycles materials).

[0099] Next, we will explain how to use the Carbon Cycle System 1000 (carbon cycle method).

[21] First, the same process as in the above process [1] is carried out.

[22] Next, the same process as in the above process [2] is carried out.

[0100] In step

[22] described above, the temperature of the first reactor 4a (exhaust gas, reducing agent 4R) (first reaction temperature) is preferably set in the same manner as in step [2] described above. Furthermore, the pressure of the first reactor 4a (exhaust gas, reducing agent 4R) (first reaction pressure) is preferably set in the same manner as in step [2] above.

[0101]

[23] Perform the same steps as in step [3] above.

[24] Perform the same steps as in step [4] above.

[0102] In step

[24] above, the temperature (reaction temperature) of the first reactor 4b (reducing gas, reducing agent 4R) is preferably set in the same way as in step [4] above. Furthermore, the pressure of the first reactor 4b (reducing gas, reducing agent 4R) (first reaction pressure) is preferably set in the same manner as in step [4] above.

[0103]

[25] Next, the same process as in the above process [5] is carried out.

[0104]

[26] Next, the same process as in the above process [6] is carried out.

[27] Next, the same process as in the above process [7] is carried out. In this embodiment, the generated gas (mixed gas) containing carbon material is discharged to the generated gas supply unit 60 via the gas line GL5.

[0105]

[28] Next, a generated gas containing carbon material is supplied from the generated gas supply unit 60 to the ore via the gas line GL70 and mixed. As a result, the carbon material is supported on the ore.

[29] Next, in this state, the ore is supplied to the blast furnace 101 along with coke, etc., as needed. In the blast furnace 101, the target metal is separated from the ore and recovered. At this time, exhaust gas containing carbon dioxide is generated. This process

[29] constitutes a smelting process in which ore is supplied together with carbon material for smelting. This exhaust gas goes through the above processes

[21] to

[27] , and carbon material is generated again.

[0106] <<Second Embodiment>> Next, a second embodiment of the carbon recycling system of the present invention will be described. Figure 10 is a schematic diagram showing the configuration of a second embodiment of the carbon recycling system of the present invention. The carbon recycling system 1000 of the second embodiment will be described below, focusing on the differences from the carbon recycling system 1000 of the first embodiment, and similar matters will be omitted from the explanation.

[0107] In the second embodiment, gas lines GL6a and GL6b branch off from gas lines GL4a and GL4b midway and merge at gas confluence J1 to form gas line GL6. A switching valve is also provided at the branching point between gas lines GL4a and GL4b and gas lines GL6a and GL6b. The exhaust gas discharged from the first reactors 4a and 4b passes through gas lines GL4a, GL4b, and GL4 and is supplied to the second reactor 5. The reducing gas discharged from the first reactors 4a and 4b passes through gas lines GL6a, GL6b, and GL6, and after, for example, water is removed, it is returned to the reducing gas supply unit 2.

[0108] In other words, in this embodiment, the exhaust gas after passing through the first reactors 4a and 4b is separated from the reduced gas after passing through the first reactors 4a and 4b. The exhaust gas that has passed through the first reactors 4a and 4b is then supplied to the second reactor 5 without merging with the reducing gas that has passed through the first reactors 4a and 4b. With this configuration, exhaust gas with reduced water contamination can be supplied to the second reactor 5. Therefore, a decrease in the efficiency of carbon monoxide conversion to carbon materials can be prevented or suppressed, and the amount produced can be increased.

[0109] <<Third Embodiment>> Next, a third embodiment of the carbon recycling system of the present invention will be described. Figure 11 is a schematic diagram showing the configuration of a third embodiment of the carbon recycling system of the present invention. The carbon recycling system 1000 of the third embodiment will be described below, focusing on the differences from the carbon recycling system 1000 of the first embodiment, and similar matters will be omitted from the explanation. The carbon recycling system 1000 of the third embodiment includes a recovery unit 9 instead of a generated gas supply unit 60.

[0110] The recovery unit 9 recovers carbon material from the gas (product gas) generated in the second reactor 5. This recovery unit 9 can be configured by combining one or more of the following: an elutriation device, a centrifugal separator, an electrostatic precipitator, and a filter device. The recovery unit 9 is connected to the gas line GL1 via the return gas line GL8. As described above, in the second reactor 5, a product gas containing carbon dioxide in addition to carbon material is generated from carbon monoxide. Therefore, the generated gas is separated into carbon material and generated gas containing carbon dioxide by passing through the recovery unit 9.

[0111] The generated gas, after the carbon material has been recovered in the recovery section 9, is returned to the first reactors 4a and 4b via gas lines GL70 and GL1. With this configuration, the generated gas after passing through the recovery unit 9 can be effectively utilized without being discarded. In particular, since the generated gas after passing through the recovery unit 9 has a sufficiently high concentration of carbon dioxide, even when mixed with exhaust gas, it is possible to effectively prevent a decrease in the conversion efficiency of carbon dioxide to carbon monoxide in the first reactors 4a and 4b.

[0112] Furthermore, the carbon recycling system 1000 of the third embodiment further includes a compression unit 12 for compressing the carbon material recovered in the recovery unit 9. By compressing the carbon material, a compressed material is formed, which is then supplied to the blast furnace 101 together with the ore. In other words, the compressed material can be used as a substitute for coke. As described above, the carbon material obtained has a low impurity content, making it possible to smelt high-quality metals. The compression unit 12 can be configured, for example, as a pelletizing device (tablet press).

[0113] The shape of the compressed material is preferably spherical, polyhedral, or the like. Using a compressed material of such shape can promote the flow of gas and molten ore within the blast furnace 101. From this viewpoint, the maximum length (e.g., diameter) between two points on the outer shape of the compressed material's cross-section is preferably 10 mm or more and 100 mm or less, and more preferably 20 mm or more and 80 mm or less. When forming the compressed material, a mixture of carbon material, powdered ore, limestone, etc., may be used.

[0114] <<Fourth Embodiment>> Next, a fourth embodiment of the carbon recycling system of the present invention will be described. Figure 12 is a schematic diagram showing the configuration of a fourth embodiment of the carbon recycling system of the present invention. The carbon recycling system 1000 of the fourth embodiment will be described below, focusing on the differences from the carbon recycling system 1000 of the first embodiment, and similar matters will be omitted from the explanation. The carbon recycling system 1000 of the fourth embodiment includes a separation unit 11 for separating carbon dioxide from exhaust gas, located in the middle of the gas line GL1 (upstream of the first reaction unit 4).

[0115] By passing the exhaust gas through the separation section 11, the concentration of carbon dioxide in the exhaust gas can be increased. This makes it possible to further improve the efficiency of carbon dioxide conversion to carbon monoxide in the first reactors 4a and 4b. Methods for separating carbon dioxide from exhaust gas include, for example, cryogenic separators, pressure swing adsorption (PSA) separators, membrane separators, temperature swing adsorption (TSA) separators, amine absorption separators, and amine adsorption separators. One of these can be used alone or in combination of two or more.

[0116] In the first to fourth embodiments described above, in the first reactors 4a and 4b, when exhaust gas comes into contact with the reducing agent 4R, carbon monoxide is produced by the reduction reaction of carbon dioxide, and at least a portion of the oxygen element released from carbon dioxide is captured by the reducing agent 4R. Subsequently, when the reducing gas comes into contact with the reducing agent 4R, it is transferred to hydrogen (reducing substance), and water (oxide of the reducing substance) is produced. In other words, in the first reactors 4a and 4b, at least a portion of the oxygen element can be separated within the carbon dioxide reduction reaction system (reaction field). A reactor capable of separating at least a portion of the oxygen element within the carbon dioxide reduction reaction system can employ the configuration shown in Figure 5.

[0117] According to the carbon material manufacturing apparatus, carbon material manufacturing method, and carbon material manufacturing system described above, carbon materials can be efficiently produced from carbon dioxide. In particular, by using the chemical looping method to produce carbon monoxide from carbon dioxide, the conversion efficiency (conversion rate) to carbon monoxide can be increased, thereby significantly improving the efficiency of carbon monoxide production and, consequently, the efficiency of carbon material production. Furthermore, by increasing the pressure of the gas supplied in the preceding stage of the second reaction section, the efficiency of carbon material production can be significantly increased. Furthermore, according to the carbon material manufacturing apparatus, carbon material manufacturing system, and carbon material manufacturing method described above, it is possible to manufacture carbon materials with an extremely low content of solid impurities. In particular, the resulting carbon material has a low content of solid impurities, making it suitable for a variety of applications.

[0118] According to the carbon recycling system and carbon recycling method described above, the target metal can be efficiently produced using carbon materials generated from exhaust gas. In particular, the resulting carbon material has a low impurity content, which can improve the quality of the smelted metal.

[0119] Furthermore, they may be provided in the following embodiments.

[0120] (1A) A carbon material manufacturing apparatus comprising: a first reaction unit for generating carbon monoxide from carbon dioxide; a second reaction unit for generating the carbon material from the carbon monoxide; and a gas line connecting the first reaction unit and the second reaction unit, wherein the first reaction unit has at least one reactor containing a reducing agent, the reducing agent reduces the carbon dioxide to carbon monoxide by contact with a raw material gas containing carbon dioxide and is brought into an oxidized state, and the oxidized reducing agent is reduced by contact with a reducing gas containing a reducing substance.

[0121] (2A) A carbon material manufacturing apparatus as described in (1A) above, wherein the first reaction section has a plurality of reactors, and each reactor is supplied with the raw material gas and the reducing gas in a switching manner.

[0122] (3A) A carbon material manufacturing apparatus as described in (2A) above, wherein the apparatus is configured to separate the raw material gas after it has passed through the reactor from the reducing gas after it has passed through the reactor.

[0123] (4A) A carbon material manufacturing apparatus as described in (3A) above, wherein the raw material gas after passing through the reactor is supplied to the second reaction section.

[0124] (5A) A carbon material manufacturing apparatus according to any one of the above items (1A) to (4A), further comprising a recovery unit for recovering the carbon material from the gas generated in the second reaction unit.

[0125] (6A) A carbon material manufacturing apparatus as described in (5A) above, wherein the second reaction unit generates carbon dioxide from carbon monoxide in addition to the carbon material, and further comprises a return gas line that connects the recovery unit and the first reaction unit and returns the gas after the carbon material has been recovered in the recovery unit to the first reaction unit.

[0126] (7A) A carbon material manufacturing apparatus according to any one of the above items (1A) to (6A), further comprising a pressure adjustment unit provided in the middle of the gas line for increasing the pressure of the gas passing through the gas line.

[0127] (8A) A carbon material manufacturing apparatus as described in (7A) above, wherein the pressure of the gas after pressurization by the pressure adjustment unit is 0.1 MPaG or higher.

[0128] (9A) A carbon material manufacturing apparatus as described in (7A) or (8A) above, wherein the second reaction temperature in the second reaction section is lower than the first reaction temperature in the first reaction section.

[0129] (10A) A carbon material manufacturing apparatus as described in (9A) above, wherein the second reaction temperature is 850°C or lower.

[0130] (11A) A carbon material manufacturing system comprising a carbon material manufacturing apparatus described in any one of the above items (1A) to (10A), and a gas supply unit connected to the carbon material manufacturing apparatus for supplying a raw material gas containing carbon dioxide.

[0131] (12A) A carbon circulation system comprising a carbon material manufacturing apparatus described in any one of (1A) to (10A) above, and a melting furnace that supplies ore together with the carbon material for smelting, wherein the first reaction unit is configured to produce carbon monoxide from the carbon dioxide contained in the exhaust gas.

[0132] (13A) A carbon recycling system in which the carbon material is supplied to the melting furnace in a state supported on the ore.

[0133] (14A) A carbon recycling system according to (12A) or (13A) above, further comprising a compression section for compressing the carbon material to obtain a compressed product, wherein the compressed product is supplied to the melting furnace together with the ore.

[0134] (15A) A carbon cycle system according to any one of the above items (12A) to (14A), further comprising a separation unit provided upstream of the first reaction unit for separating carbon dioxide from the exhaust gas.

[0135] (16A) A carbon recycling system according to any one of the above items (12A) to (15A), wherein the exhaust gas is a gas discharged from the same melting furnace as the melting furnace.

[0136] (17A) A method for producing a carbon material, comprising a first production step of producing carbon monoxide from carbon dioxide, and a second production step of producing the carbon material from the carbon monoxide, wherein the first production step involves contacting a raw material gas containing carbon dioxide with a reducing agent to reduce the carbon dioxide and convert it into carbon monoxide, while simultaneously oxidizing the reducing agent, and then reducing the reducing gas containing a reducing substance by contacting the oxidized reducing agent.

[0137] (18A) A method for producing a carbon material as described in (17A) above, further comprising a pressure adjustment step of increasing the pressure of the gas produced in the first production step prior to the second production step.

[0138] (19A) A carbon recycling method comprising a method for producing a carbon material as described in (17A) above, and a smelting step of supplying ore together with the carbon material produced in the second production step and smelting it.

[0139] (1B) A carbon material manufacturing apparatus comprising: a first reaction unit for generating carbon monoxide from carbon dioxide; a second reaction unit for generating the carbon material from the carbon monoxide; a gas line connecting the first reaction unit and the second reaction unit; and a pressure adjustment unit provided in the middle of the gas line for increasing the pressure of the gas passing through the gas line.

[0140] (2B) A carbon material manufacturing apparatus as described in (1B) above, wherein the pressure of the gas after pressurization by the pressure adjustment unit is 0.1 MPaG or higher.

[0141] (3B) A carbon material manufacturing apparatus as described in (1B) or (2B) above, wherein the second reaction temperature in the second reaction section is lower than the first reaction temperature in the first reaction section.

[0142] (4B) A carbon material manufacturing apparatus as described in (3B) above, wherein the second reaction temperature is 850°C or lower.

[0143] (5B) A carbon material manufacturing apparatus according to any one of the above items (1B) to (4B), wherein the first reaction section contains a reducer that is converted to carbon monoxide by a reduction reaction of carbon dioxide produced by contact with a raw material gas containing carbon dioxide, and has at least one reactor capable of separating at least a portion of the oxygen element released from the carbon dioxide within the system of the reduction reaction.

[0144] (6B) A carbon material manufacturing apparatus as described in (5B) above, wherein the reducing agent is a reducing agent that reduces carbon dioxide to carbon monoxide and is brought into an oxidized state by contact with the raw material gas, and the reducing agent in the oxidized state is a reducing agent that is reduced by contact with a reducing gas containing a reducing substance.

[0145] (7B) A carbon material manufacturing apparatus as described in (6B) above, wherein the first reaction section has a plurality of reactors, and each reactor is supplied with the raw material gas and the reducing gas in a switching manner.

[0146] (8B) A carbon material manufacturing apparatus as described in (7B) above, wherein the apparatus is configured to separate the raw material gas after it has passed through the reactor from the reducing gas after it has passed through the reactor.

[0147] (9B) A carbon material manufacturing apparatus as described in (8B) above, wherein the raw material gas after passing through the reactor is supplied to the second reaction section.

[0148] (10B) A carbon material manufacturing apparatus according to any one of the above items (1B) to (9B), further comprising a recovery unit for recovering the carbon material from the gas generated in the second reaction unit.

[0149] (11B) A carbon material manufacturing apparatus as described in (10B) above, wherein the second reaction unit generates carbon dioxide from carbon monoxide in addition to the carbon material, and further comprises a return gas line that connects the recovery unit and the first reaction unit and returns the gas after the carbon material has been recovered in the recovery unit to the first reaction unit.

[0150] (12B) A carbon material manufacturing system comprising a carbon material manufacturing apparatus described in any one of the above items (1B) to (11B), and a gas supply unit connected to the carbon material manufacturing apparatus for supplying a raw material gas containing carbon dioxide.

[0151] (13B) A method for producing a carbon material, comprising: a first production step of producing carbon monoxide from carbon dioxide; a second production step of producing the carbon material from the carbon monoxide; and a pressure adjustment step of increasing the pressure of the gas produced in the first production step prior to the second production step.

[0152] (1C) A carbon material manufacturing apparatus comprising a first reaction section for generating carbon monoxide from carbon dioxide and a second reaction section for generating a carbon material from the carbon monoxide, wherein the content of solid impurities in the carbon material is 1% by mass or less.

[0153] (2C) A carbon material manufacturing apparatus as described in (1C) above, wherein the first reaction section contains a reducer that is converted to carbon monoxide by a reduction reaction of carbon dioxide produced by contact with a raw material gas containing carbon dioxide, and has at least one reactor capable of separating at least a portion of the oxygen element released from the carbon dioxide within the reduction reaction system.

[0154] (3C) A carbon material manufacturing apparatus as described in (2C) above, wherein the reducing agent is a reducing agent that reduces carbon dioxide to carbon monoxide and is brought into an oxidized state by contact with the raw material gas, and the reducing agent in the oxidized state is a reducing agent that is reduced by contact with a reducing gas containing a reducing substance.

[0155] (4C) A carbon material manufacturing apparatus as described in (3C) above, wherein the first reaction section has a plurality of reactors, and each reactor is supplied with the raw material gas and the reducing gas in a switching manner.

[0156] (5C) A carbon material manufacturing apparatus as described in (4C) above, wherein the apparatus is configured to separate the raw material gas after it has passed through the reactor from the reducing gas after it has passed through the reactor.

[0157] (6C) A carbon material manufacturing apparatus as described in (5C) above, wherein the raw material gas after passing through the reactor is supplied to the second reaction section.

[0158] (7C) A carbon material manufacturing apparatus according to any one of the above items (1C) to (6C), further comprising a recovery unit for recovering the carbon material from the gas generated in the second reaction unit.

[0159] (8C) A carbon material manufacturing apparatus as described in (7C) above, wherein the second reaction unit is configured to generate carbon dioxide from carbon monoxide in addition to the carbon material, and to return the gas after the carbon material has been recovered in the recovery unit to the first reaction unit via a return gas line connecting the recovery unit and the first reaction unit.

[0160] (9C) A carbon material manufacturing apparatus according to any one of items (1C) to (8C) above, wherein the carbon material is used for at least one of secondary battery material, tire filler, colorant for resin material or rubber material, UV protection / absorbent material, fuel cell electrode material, and heat dissipation agent.

[0161] (10C) A carbon material manufacturing system comprising a carbon material manufacturing apparatus described in any one of the above items (1C) to (9C), and a gas supply unit connected to the carbon material manufacturing apparatus for supplying a raw material gas containing carbon dioxide.

[0162] (11C) A carbon material manufacturing system as described in (10C) above, further comprising a separation unit provided between the gas supply unit and the first reaction unit for separating carbon dioxide from the raw material gas.

[0163] (12C) A carbon material manufacturing system as described in (11C) above, wherein the gas supply unit is a furnace related to a smelter.

[0164] (13C) A carbon material manufacturing system as described in (12C) above, wherein the furnace associated with the smelter is a blast furnace.

[0165] (14C) A method for producing a carbon material, comprising a first production step of producing carbon monoxide from carbon dioxide, and a second production step of producing the carbon material from the carbon monoxide, wherein the content of solid impurities in the carbon material is 1% by mass or less.

[0166] (1D) A carbon cycle system comprising: a first reaction unit that generates carbon monoxide from carbon dioxide contained in exhaust gas; a second reaction unit that generates a carbon material from the carbon monoxide; and a melting furnace that supplies ore together with the carbon material for smelting, wherein the first reaction unit contains a reducer that is converted to carbon monoxide by a reduction reaction of carbon dioxide that occurs in contact with the exhaust gas, and has at least one reactor capable of separating at least a portion of the oxygen element released from the carbon dioxide within the reduction reaction system, wherein the reducer is a reducing agent that reduces carbon dioxide to carbon monoxide and is brought into an oxidized state in contact with the exhaust gas, and the reducing agent in the oxidized state is a reducing agent that is reduced by contact with a reducing gas containing a reducing substance.

[0167] (2D) A carbon recycling system in which the carbon material is supplied to the melting furnace in a state supported on the ore, in the carbon recycling system described in (1D) above.

[0168] (3D) A carbon recycling system according to (1D) or (2D) above, further comprising a compression section for compressing the carbon material to obtain a compressed product, wherein the compressed product is supplied to the melting furnace together with the ore.

[0169] (4D) A carbon cycle system according to any one of the above items (1D) to (3D), further comprising a separation unit provided upstream of the first reaction unit for separating carbon dioxide from the exhaust gas.

[0170] (5D) A carbon recycling system according to any one of the above items (1D) to (4D), wherein the exhaust gas is a gas discharged from the same melting furnace as the melting furnace.

[0171] (6D) A carbon circulation system according to any one of the above items (1D) to (5D), wherein the first reaction unit has a plurality of reactors, and each reactor is supplied with the exhaust gas and the reducing gas in a switching manner.

[0172] (7D) A carbon cycle system as described in (6D) above, wherein the exhaust gas after passing through the reactor and the reducing gas after passing through the reactor are configured to be separated.

[0173] (8D) A carbon circulation system in which the exhaust gas after passing through the reactor is supplied to the second reaction section.

[0174] (9D) A carbon recycling system according to any one of the above items (1D) to (8D), further comprising a recovery unit for recovering the carbon material from the gas produced in the second reaction unit.

[0175] (10D) A carbon recycling system as described in (9D) above, wherein the second reaction unit generates carbon dioxide from carbon monoxide in addition to the carbon material, and further comprises a return gas line that connects the recovery unit and the first reaction unit and returns the gas after the carbon material has been recovered in the recovery unit to the first reaction unit.

[0176] (11D) A carbon cycle method comprising: a first production step of producing carbon monoxide from carbon dioxide contained in exhaust gas; a second production step of producing the carbon material from the carbon monoxide; and a smelting step of supplying ore together with the carbon material and smelting, wherein the first production step is carried out using at least one reactor capable of separating at least a portion of the oxygen element released from the carbon dioxide within the system of the reduction reaction, the reduced material is a reducing agent that reduces the carbon dioxide to carbon monoxide and is brought into an oxidized state upon contact with the exhaust gas, and the oxidized reducing agent is a reducing agent that is reduced upon contact with a reducing gas containing a reducing substance. Of course, this is not always the case.

[0177] As previously described, various embodiments of the present invention have been explained, but these are merely examples and do not limit the scope of the invention in any way. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0178] For example, the carbon material manufacturing apparatus, the carbon material manufacturing system, and the carbon recycling system may each have other optional additional configurations compared to the above embodiments, may be replaced with any configuration that performs a similar function, and some configurations may be omitted. Furthermore, the carbon material manufacturing method and carbon recycling method of the present invention may each have other optional additional steps compared to the above embodiments, may be replaced by any steps that perform similar functions, and some steps may be omitted. In the above embodiments, a gas containing hydrogen was described as a representative reducing gas. However, as a reducing gas, a gas containing at least one selected from hydrocarbons (e.g., methane, ethane, acetylene, etc.) and ammonia can also be used as a reducing substance, either in place of or in addition to hydrogen.

[0179] Furthermore, the first reactor in the present invention may be a reactor configured such that at least a portion of the oxygen element released from carbon dioxide by the reduction reaction is not separated within the reduction reaction system. Such a reactor can be described as an apparatus that utilizes a reverse water-gas shift reaction, in which carbon dioxide and hydrogen are simultaneously brought into contact with a reducing agent 4R to convert carbon dioxide to carbon monoxide and hydrogen (the reducing agent) to water. In this reactor, at least some of the oxygen released from carbon dioxide reacts with hydrogen to produce water without being separated from the reduction reaction system (reaction field). However, if a reactor is used that can separate at least some of the oxygen elements released from carbon dioxide within the reduction reaction system (reaction field), as described above, it becomes difficult for the reaction products, carbon monoxide and water, to coexist in the system. This prevents or suppresses the decrease in the efficiency of carbon dioxide conversion to carbon monoxide due to constraints on chemical equilibrium.

[0180] Furthermore, the carbon material manufacturing system 10 (carbon material manufacturing apparatus 100) may be configured by combining any of the configurations of the first to seventh embodiments described above. For example, the first reaction section 4 can be configured as an electrochemical cell as shown in Figure 5, and the second reaction section 5 can be configured as a reactor that carries out the reaction of formula 5 above.

[0181] Furthermore, the carbon cycle system 1000 may combine any of the configurations of the first to fourth embodiments described above with an electrochemical cell as shown in Figure 5. For example, the first reaction section 4 can be configured as an electrochemical cell as shown in Figure 5, and the second reaction section 5 can be configured as a reactor that carries out the reaction of formula 5 above. [Explanation of symbols]

[0182] 10: Carbon material manufacturing systems 100: Equipment for manufacturing carbon materials 1000: Carbon cycle system 1: Exhaust gas supply unit 101: Blast furnace (gas supply section) 2: Reducing gas supply unit 3: Gas switching section 4: First reaction section 4a: First reactor 4b: First reactor 41: Body 42: Housing 421a: Cathode side inlet port 421b: Cathode side exit port 422a: Anode-side inlet port 422b: Anode-side exit port 43: Interior space 45: Cathode 46: Anode 47: Solid electrolyte layer 48:Power supply 4R: Reducing agent 5: Second reactor (second reaction section) 6: Gas discharge section 60: Gas Production Supply Unit 8: Pressure adjustment section 9: Collection Department 11: Separation section 12: Compression section GL1: Gas line GL2: Gas line GL3a: Gas line GL3b: Gas line GL4: Gas line GL4a: Gas line GL4b: Gas line GL5: Gas line GL6: Gas line GL6a: Gas line GL6b: Gas line GL7: Returned Gas Line GL8: Returned Gas Line GL70: Gas line J: Gas confluence J1: Gas confluence

Claims

1. A carbon material manufacturing apparatus, A first reaction section that produces carbon monoxide from carbon dioxide, A second reaction unit for generating the carbon material from the carbon monoxide, The system includes a gas line connecting the first reaction section and the second reaction section, The first reaction unit has at least one reactor containing a reducing agent, A carbon material manufacturing apparatus, wherein the reducing agent is brought into contact with a raw material gas containing carbon dioxide to reduce the carbon dioxide and convert it into carbon monoxide, and is also brought into an oxidized state, and the oxidized reducing agent is reduced by contact with a reducing gas containing a reducing substance.

2. In the carbon material manufacturing apparatus according to claim 1, The first reaction section has a plurality of reactors, A carbon material manufacturing apparatus, wherein the raw material gas and the reducing gas are supplied to each of the reactors in a switching manner.

3. In the carbon material manufacturing apparatus according to claim 2, A carbon material manufacturing apparatus configured to separate the raw material gas after it has passed through the reactor from the reducing gas after it has passed through the reactor.

4. In the carbon material manufacturing apparatus according to claim 3, The raw material gas, after passing through the reactor, is supplied to the second reaction section in a carbon material manufacturing apparatus.

5. In the apparatus for manufacturing carbon materials according to any one of claims 1 to 4, Furthermore, the apparatus for producing carbon materials includes a recovery unit for recovering the carbon material from the gas generated in the second reaction unit.

6. In the carbon material manufacturing apparatus according to claim 5, The second reaction unit generates carbon dioxide from the carbon monoxide in addition to the carbon material, Furthermore, the carbon material manufacturing apparatus includes a return gas line that connects the recovery unit and the first reaction unit, and returns the gas remaining after the carbon material has been recovered in the recovery unit to the first reaction unit.

7. In the carbon material manufacturing apparatus according to any one of claims 1 to 6, Furthermore, the apparatus for manufacturing carbon materials includes a pressure adjustment unit installed in the middle of the gas line to increase the pressure of the gas passing through the gas line.

8. In the carbon material manufacturing apparatus according to claim 7, A carbon material manufacturing apparatus wherein the pressure of the gas after pressurization by the pressure adjustment unit is 0.1 MPaG or higher.

9. In the carbon material manufacturing apparatus according to claim 7 or claim 8, A carbon material manufacturing apparatus wherein the second reaction temperature in the second reaction section is lower than the first reaction temperature in the first reaction section.

10. In the carbon material manufacturing apparatus according to claim 9, A carbon material manufacturing apparatus wherein the second reaction temperature is 850°C or lower.

11. A carbon material manufacturing system, A carbon material manufacturing apparatus according to any one of claims 1 to 10, A carbon material manufacturing system comprising a gas supply unit connected to the carbon material manufacturing apparatus and supplying a raw material gas containing carbon dioxide.

12. Carbon cycle system A carbon material manufacturing apparatus according to any one of claims 1 to 10, The system comprises a melting furnace that supplies ore together with the carbon material for smelting, The first reaction unit is configured to produce carbon monoxide from the carbon dioxide contained in the exhaust gas, in a carbon cycle system.

13. In the carbon cycle system according to claim 12, A carbon recycling system in which the carbon material is supplied to the melting furnace while supported on the ore.

14. In the carbon cycle system according to claim 12 or claim 13, Furthermore, it includes a compression section for compressing the carbon material to obtain a compressed product, The compressed material is supplied to the melting furnace along with the ore, forming a carbon recycling system.

15. In the carbon cycle system according to any one of claims 12 to 14, Furthermore, a carbon recycling system comprising a separation unit provided upstream of the first reaction unit for separating carbon dioxide from the exhaust gas.

16. In the carbon cycle system according to any one of claims 12 to 15, The carbon recycling system wherein the exhaust gas is gas discharged from the same melting furnace as the melting furnace.

17. A method for manufacturing carbon materials, The first production step involves generating carbon monoxide from carbon dioxide, The process includes a second production step of generating the carbon material from the carbon monoxide, The first production step is a method for producing a carbon material, wherein the carbon dioxide is reduced to carbon monoxide by contacting a raw material gas containing carbon dioxide with a reducing agent, and the reducing agent is brought into an oxidized state, and the reducing gas containing a reducing substance is brought into contact with the oxidized reducing agent to further reduce it.

18. In the method for producing a carbon material according to claim 17, A method for producing a carbon material, further comprising a pressure adjustment step of increasing the pressure of the gas produced in the first production step prior to the second production step.

19. A carbon cycle method, A method for producing a carbon material according to claim 17, A carbon recycling method comprising a smelting step of supplying ore together with the carbon material produced in the second generation step and smelting it.

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