Method for production of carbon monoxide, production method for syngas or chemical obtained with syngas, and reactor

Abstract

To provide a novel carbon monoxide production method with a low risk of water generation, and a method for producing carbon monoxide and hydrogen at any H2 / CO ratio and a compact device.SOLUTION: There is provided a carbon monoxide production method in which reactions represented by the following formula (1) and formula (2) are allowed to sequentially proceed under a substantially anhydrous environment, thereby making it possible to produce H2 and CO separately while water is not produced from a reaction system as a by-product: (1) CH4→C+2H2 and (2) C+CO2→2CO. The method, when mixture is performed at a certain ratio with molar flow rate regulation, corresponds to a method for producing syngas at any H2 / CO ratio. There is also provided a reactor which includes: a reaction furnace which contains a structure catalyst having catalysis of methane thermal decomposition reaction; and a CO detector on a flow channel connected to a gas discharge port of the reaction furnace.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a novel method for synthesizing carbon monoxide with less risk of water generation, and an apparatus for producing hydrogen and carbon monoxide. [Background technology]

[0002] Syngas, which is primarily composed of carbon monoxide and hydrogen and is produced by reforming natural gas, is used as a raw material to make a variety of synthetic compounds, including fuels, synthetic resins, and pharmaceuticals. Many reactions for producing synthesis gas have been proposed, but the appropriate use is determined by the H2 / CO ratio of the resulting synthesis gas, as follows: TIFF2024178069000002.tif28116

[0003] The steam reforming method (SRM) is the most practical method for producing synthetic gas. However, the H2 / CO ratio of the synthetic gas is too high for the production of synthetic fuels or methanol, so it is necessary to combine it with other methods to lower the H2 / CO ratio. There is also the problem that the equipment becomes large.

[0004] The catalytic partial oxidation process (D-CPOX process) and the non-catalytic partial oxidation process (POX process) are exothermic reactions and are considered to be ideal methods for producing synthesis gas from the standpoint of energy input. However, they have problems such as difficulty in reaction control, low thermal efficiency, deposition of heavy hydrocarbons and carbon, and difficulty in continuous operation.

[0005] Recently, methane dry reforming has been attracting attention as an environmentally green reforming method using methane and carbon dioxide, which are greenhouse gases, as raw materials (Non-Patent Document 1, etc.).

[0006] The traditional dry reforming reaction (equation (3)) for producing synthesis gas from methane and carbon dioxide is carried out at high temperatures, and therefore the supported catalysts used have problems such as a tendency for catalytic activity to decrease due to agglomeration of catalyst particles on the support surface and carbon deposition, making it known that it is difficult to maintain catalytic activity (Patent Document 1, Non-Patent Document 2, Non-Patent Document 3). Furthermore, in many cases of reactions for producing chemical products using CO2 as a raw material, water is generated as a by-product along with the target product. This is mainly due to the reverse water gas shift reaction (equation (4)), in which the product hydrogen is oxidized to water. CH4 + CO2 → 2CO + 2H2 (3) CO2+H2→ CO+H2O (4) The by-product water causes 1) a decrease in the equilibrium conversion rate due to the progression of a reverse reaction, and 2) the deactivation of the catalyst (catalyst poisoning) due to the reaction between the catalyst and water, thereby hindering the efficient progress of the reaction (Non-Patent Document 4).

[0007] Methanol synthesis or synthesis of polycarbonate raw materials are typical examples where the by-production of water is an issue. Therefore, the development of a reaction system that efficiently removes the by-product water from the reaction system is considered to be one of the fundamental technological developments for the production of useful chemicals using CO2 as a raw material (Non-Patent Document 4). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2014-24696 A [Non-patent literature]

[0009] [Non-Patent Document 1] Ogawa et al., "Catalyst for methane, carbon dioxide, and hydrogen," Chemistry and Education, Vol. 66, No. 2, 2018 (URL: https: / / www.jstage.jst.go.jp / article / kakyoshi / 66 / 2 / 66_68 / _pdf) [Non-Patent Document 2] Cabinet Office, "Comprehensive Survey on Technical Issues of Promising Technologies in the Energy and Environmental Fields" Report, March 2018 (URL: https: / / www8.cao.go.jp / cstp / stmain / houkokusho.pdf) [Non-Patent Document 3] Fukuhara et al., "Ni-based structured catalytic reaction system with both a CH4 dry reforming site and a carbon capture site," Program of the 66th Research Presentation Meeting of the Japan Petroleum Institute, May 2017 (URL: https: / / www.jstage.jst.go.jp / article / sekiyu / 2017 / 0 / 2017_5 / _pdf) [Non-Patent Document 4] Cabinet Office, "Bottleneck issues in CO2 utilization and direction of research and development," p. 18, February 2018 (URL: https: / / www8.cao.go.jp / cstp / stmain / 20180221bottleneck.html) Summary of the Invention [Problem to be solved by the invention]

[0010] In view of the above-mentioned current situation, an object of the present invention is to provide a novel method for producing carbon monoxide with little risk of water generation, a method for producing carbon monoxide and hydrogen, and a method for producing carbon monoxide and hydrogen at any H2 / CO ratio, and a small-sized production apparatus. [Means for solving the problem]

[0011] The present inventors have noticed that the methane dry foaming reaction of formula (3) can be divided into formulas (1) and (2). CH4 + CO2 → 2CO + 2H2 ···(3) CH4 → C + 2H2 (1) C + CO2 ⇔ 2CO (2) Equation (1) is the thermal decomposition of methane, and the present inventors have previously demonstrated that the reaction can be promoted at a high conversion rate by radiative heating of a nickel-based structure catalyst having a copper intermediate layer (for example, International Publication No. 2021 / 079660 and International Publication No. 2023 / 013182). Equation (2) is known to be a reversible reaction commonly known as the Boudouard reaction.

[0012] If the reactions of equations (1) and (2) can be smoothly advanced to the right, it is expected that the methane dry-forming reaction of equation (3) can be effectively advanced while avoiding the progress of reaction (4), which produces water.

[0013] One aspect of the present invention made to achieve the above-mentioned object is a method for producing carbon monoxide or carbon monoxide and hydrogen, which comprises sequentially carrying out reactions represented by the following formulas (1) and (2) in a substantially anhydrous environment: CH4 → C + 2H2 (1) C + CO2 → 2CO (2) According to this method (Sequential Dry Reforming of Methane (SDRM)), the reactions (1) and (2) are carried out sequentially, so that H2 and CO can be produced separately from the reaction system without producing water as a by-product due to the reverse water-gas shift reaction or the like.

[0014] In the above method, it is preferable that the carbon dioxide (CO2) is CO2 stored by carbon dioxide capture and storage (CCS) technology. At present, the utilization of large amounts of CO2 captured by CCS is an issue (Non-Patent Document 4), and this is a promising utilization method of high-concentration CO2 obtained without separation and purification, and the obtained CO is the only compound that can be used industrially by reducing CO2 (Non-Patent Document 2, p. 95).

[0015] It is preferable that the reaction of formula (1) above is carried out using a catalyst that catalyzes the thermal decomposition of methane, and the reaction of formula (2) above is carried out in the presence of carbon produced in the reaction of formula (1) above. This has the advantage that the same catalyst can be used for each reaction without replacing it. In addition, by carrying out the reaction of formula (2) above in the presence of carbon produced in the reaction of formula (1) above, the produced carbon can be effectively consumed and utilized as a raw material for CO.

[0016] Another aspect of the present invention is a method for producing a synthesis gas or a chemical product using the same, which comprises mixing the hydrogen and carbon monoxide obtained by the above method at a constant ratio by adjusting the molar flow rates. The above synthesis gas or the method for producing a chemical product using the same may further comprise adjusting the H2 / CO ratio by adding hydrogen derived from renewable energy. This makes it possible to adjust the H2 / CO ratio from around 1 obtained by the SDRM method to any level exceeding 2.

[0017] Another aspect of the present invention is a reaction device including a reactor containing a structure catalyst having a catalytic action for the pyrolysis reaction of methane and a CO detector on a flow path connected to the gas outlet of the reactor. With such a configuration, a small-sized device suitable for carrying out the SDRM method of generating carbon monoxide by utilizing carbon generated by the catalytic action of the pyrolysis reaction of methane can be obtained. In addition, since a structure catalyst is used, the amount of generated carbon (filamentous carbon, carbon nanotubes, etc.) temporarily stored is reduced due to clogging of the reactor by the generated carbon as in the case of a catalyst using a support, and the risk of an increase in the energy required to deliver the reaction gas, etc. is also reduced.

[0018] The above-mentioned reaction apparatus is preferably one in which the reactor has one gas supply port and one gas exhaust port, and further has a supply-side three-way valve for switching the supply path to the gas supply port and a discharge-side three-way valve for switching the exhaust path from the gas exhaust port. With such a configuration, the number of pipes directly connected to the apparatus is reduced, and when the supply-side three-way valve is open in the supply direction of CH4 and the discharge-side three-way valve is open in the discharge direction of H2, it automatically closes in the supply direction of CO2 and the discharge direction of CO, and when the supply-side three-way valve is open in the supply direction of CO2 and the discharge-side three-way valve is open in the discharge direction of CO, it automatically closes in the supply direction of CH4 and the discharge direction of H2, so that the apparatus is more suitable for carrying out the SDRM method.

[0019] The above-mentioned reaction apparatus is preferably provided with a discharge-side valve for controlling the discharge of hydrogen and / or CO from the reaction furnace, and a main valve capable of releasing the gas remaining in the reaction furnace into the atmosphere, or a main valve capable of releasing the gas remaining in the reaction furnace into a flow path separate from the flow paths of hydrogen or CO, is provided at a position closer to the gas discharge port of the reaction furnace than the discharge-side valve. With such a main valve, the purity of the product gas controlled by the discharge-side valve downstream of the main valve can be improved by a purging operation with the main valve using the raw material gas. Effect of the Invention

[0020] According to the production method of the present invention, H2 and CO are produced separately from the reaction system without producing water as a by-product. Therefore, they can be used separately, and when producing synthesis gas, the H2 / CO ratio can be freely adjusted depending on the target product. Cost recovery from the thermal decomposition of methane through effective use of the by-product "solid carbon" in addition to hydrogen gas is being considered. However, if the reactor according to the present invention is used, when the market price of fixed carbon is low, there is the flexibility to take in CO2 into the reactor and use it for CO synthesis by causing the Boudouard reaction. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2A is a vertical cross-sectional view of the reaction apparatus of Experimental Example 1, and FIG. 2B is an AA cross-sectional view of the reaction apparatus. [Diagram 2] 4 is a graph showing the change in hydrogen concentration over time in Experimental Example 1. [Diagram 3] SEM image and EDS measurement results of the catalyst with the product attached. [Figure 4] A graph showing the relationship between furnace temperature and equilibrium concentration levels of CO and CO2. [Diagram 5] A graph showing the change in CO and CO2 concentration levels over time after switching from N2 gas to CO2. [Figure 6] An overview of the SDRM process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The following defines the terms used in this specification. In this specification, "in a substantially anhydrous environment" means an environment in which water or water vapor (steam) is not artificially added to or introduced into the raw materials for the purpose of involving them in the reaction. Therefore, while "in a substantially anhydrous environment," the accidental or unavoidable inclusion of water due to reactions between the raw materials and impurities, reactions between multiple impurities, etc. is permitted, it is preferable to reduce the moisture and humidity of the raw materials by contacting them with a desiccant, etc. As used herein, the term "promoting reactions sequentially" means that a plurality of reactions are allowed to proceed in a desired order and / or alternating manner, and in the case of reversible reactions, in a desired direction. In this specification, the term "structure catalyst" refers to a catalyst in which the structure itself functions as a catalyst, or a catalyst based on the structure. A structure-based catalyst generally refers to a catalyst obtained by impregnating a substrate having a shape such as a honeycomb with a slurry containing a catalyst component, but it may also be a catalyst in which an exposed non-supported catalyst layer (plated layer, sprayed layer) is formed on a structure by spraying, plating, or the like. In this specification, the term "structure" refers to an object that has a certain shape even if there is no mold to maintain the shape. The shape of the structure is not particularly limited, and examples thereof include a plate (not only a flat plate, but also a flat plate that has been subjected to any processing such as bending, folding, punching, notching, embossing, etc.), a rod, a cylinder, a porous body, a honeycomb (monolith type), a felt, a mesh, a fabric, and an expanded metal. In this specification, "Carbon dioxide capture and storage (CCS) technology" refers to technology that captures CO2 emitted from power plants, chemical plants, etc. before it is released into the atmosphere, or captures it from the atmosphere, and stores it or makes effective use of it as a resource. In this specification, "renewable energy" refers to non-fossil energy sources that are recognized as being able to be used permanently as energy sources (Article 2, Paragraph 3 of the Law Concerning the Promotion of Environmentally Friendly Use of Energy Sources and Effective Use of Fossil Energy Resources by Energy Suppliers). For example, there are seven types of energy: (a) solar power, (b) wind power, (c) hydroelectric power, (d) geothermal power, (e) solar heat, (f) heat in the atmosphere and other heat present in nature, and (g) biomass (organic matter derived from plants and animals) (Article 4 of the Enforcement Order of the Law). In this specification, the term "chemical products" refers to any product produced in the chemical industry using synthetic gas. Examples include industrial chemicals such as methacrylic acid, methanol, acetic acid, and aldehydes, synthetic fuels, chemical fertilizers, synthetic fibers, rubber, synthetic resins such as polycarbonate and urethane, pharmaceuticals, dyes, soaps, and cosmetics.

[0023] One aspect of the present invention is a method for producing carbon monoxide or carbon monoxide and hydrogen, which comprises sequentially carrying out reactions represented by the following formulas (1) and (2) in a substantially anhydrous environment: CH4 → C + 2H2 (1) C + CO2 → 2CO (2)

[0024] The reaction temperature of reaction formula (1) requires a high temperature of 1200° C. or more in the absence of a catalyst, but when a catalyst is used, it is usually set to 800° C. or more. In this specification, the reaction temperature is a value obtained by measurement using a thermocouple. When a catalyst is used, the reaction temperature of reaction formula (2) is usually set to 400°C or higher. In order to cause the reaction to proceed in a manner that favors CO production, however, the reaction temperature is preferably 650°C or higher, and more preferably 800°C or higher.

[0025] The reactions represented by the above formulas (1) and (2) may or may not require the use of a catalyst, but when the reactions are carried out at the above reaction temperatures, it is preferable to use a catalyst.

[0026] The reaction of formula (1) above is usually carried out using a catalyst that has catalytic activity for the thermal decomposition of methane. As the catalyst "that has catalytic activity for the thermal decomposition of methane", a catalyst having an exposed nickel-containing layer with a thickness of about 1 μm to 200 μm and a layer made of iron, copper, nickel, steel, cast iron, an iron-nickel alloy, or a copper alloy with a thickness of about 0.5 mm to 10 mm as a support layer is preferably used, and a catalyst having an intermediate layer containing copper with a thickness of about 1 to 1000 μm between the support layer and the nickel-containing layer is more preferably used. Here, "exposed" means that methane molecules can come into contact with the nickel-containing layer, and is not limited to being exposed to the naked eye. The nickel-containing layer may be an unsupported nickel-containing layer. "Unsupported" means that the nickel-containing component as the catalyst component is not present as particles dispersed on a porous carrier such as activated carbon or a porous oxide, but is present in an organized state. "Organized" may mean that the particles are fused together in some areas, may be fused together in the entire area, or may be melted as a whole and then cooled and solidified. The catalyst used in carrying out the production method according to the present invention is not limited to a structure catalyst, but may be a powder catalyst that cannot maintain a constant shape without a mold to maintain the shape.

[0027] The catalyst preferably has a layer of iron, copper, nickel, steel, cast iron, an iron-nickel alloy, or a copper alloy having a thickness of about 0.5 mm to 10 mm as a support layer for the nickel-containing layer, and more preferably has an intermediate layer containing copper having a thickness of about 1 to 1000 μm between the support layer and the nickel-containing layer. The support layer may be the structure itself before the nickel-containing layer is laminated, or may be a layer laminated on the structure.

[0028] The reaction of formula (2) above is usually carried out in the presence of the carbon produced in the reaction of formula (1) above. It is sufficient that some of the carbon generated here remains, and some of it may be removed. The carbon generated here tends to be observed mainly in the form of nanofibers (tip-growth form with nickel nanoparticles attached, which are shown as white dots at the tip as shown in the SEM image in Figure 3). The generated carbon containing these catalytic fine particles may have a catalytic effect in addition to serving as a raw material, but regardless of the form or role it has, it is sufficient that it exists in order to carry out the manufacturing method of the present invention. In other words, what has the catalytic effect does not in any way restrict the technical scope of the manufacturing method of the present invention.

[0029] When the present invention is considered as a method for producing carbon monoxide, there is no restriction on how the carbon and hydrogen generated in the above formula (1) are handled. That is, they may or may not be used in a subsequent reaction involving carbon monoxide, and they may be used alone or discarded.

[0030] When the present invention is considered as a method for producing carbon monoxide, the carbon monoxide may be mixed with hydrogen, methane, and other impurities. In this production method, whether or not it is necessary to remove the hydrogen and methane remaining in the previous reaction (formula (1)) when proceeding with the subsequent reaction (formula (2)) depends on the purity of the CO produced, which depends on the application. However, it is preferable to sequentially proceed the reactions represented by the above formulas (1) and (2) in a substantially oxygen-free environment (an environment not containing O2).

[0031] When the present invention is understood as a method for producing carbon monoxide and hydrogen, it is not limited to a method for producing a synthesis gas consisting of carbon monoxide and hydrogen, and the present invention also includes cases in which the uses of carbon monoxide and hydrogen are completely different. Uses of carbon monoxide other than synthesis gas include a reducing agent for metal oxides, and uses of hydrogen other than synthesis gas include a fuel for promoting the reaction of the above formula (1) or (2), a mixture with city gas, turbine fuel, and raw material for fuel cells.

[0032] The methane (CH4) used in the above formula (1) is preferably derived from natural gas. Natural gas contains methane (CH4) at high concentrations, and is abundant in supply. Furthermore, city gas, which is also derived from natural gas, can easily become a source containing high concentrations of methane if it is passed through a desulfurizer. Examples of natural gas include city gas, non-associated gas produced from gas fields, associated gas produced together with crude oil from oil fields, shale gas, methane hydrate, etc. In view of the global trend toward carbon negativity, methane derived from biogas, that is, methane obtained by separating CO2 from biogas, may be used, but there is a limit to the amount that can be supplied. Methane derived from coal gas may be used, but there is a drawback in that coal gas is essentially a mixed gas, and methane and CO2 cannot be supplied separately.

[0033] The carbon dioxide (CO2) is preferably CO2 stored using carbon dioxide capture and storage (CCS) technology. The CO2 stored using carbon dioxide capture and storage (CCS) technology may be CO2 that has already been stored and injected deep underground, CO2 that has been temporarily stored above ground in preparation for storage and injection, or CO2 that has just been separated from other gases. CO2 derived from biogas, that is, CO2 obtained by separating methane from biogas, may also be used, but there is a limit to the amount that can be supplied.

[0034] Another aspect of the present invention is a method for producing a synthesis gas or a chemical product using the same, which comprises mixing the hydrogen obtained by the above method and carbon monoxide in a fixed ratio by adjusting the molar flow rates. The molar flow rate adjustment is based on the molar ratio of carbon monoxide to hydrogen, taking into consideration the stoichiometric ratio of hydrogen to carbon monoxide in the subsequent reaction using synthesis gas, which is a mixture of hydrogen and carbon monoxide. The constant ratio here does not have to be strictly equal to the stoichiometric ratio, and can be higher or lower than the stoichiometric ratio based on established knowledge about the subsequent reaction using synthesis gas. The constant ratio can be set to, for example, ±50%, ±20%, ±5%, etc., compared to the stoichiometric ratio of the subsequent reaction.

[0035] The above-mentioned synthesis gas or the method for producing a chemical product using the synthesis gas may further include adding hydrogen derived from renewable energy to adjust the H2 / CO ratio. The hydrogen derived from renewable energy is not particularly limited, but examples thereof include hydrogen generated by water electrolysis using surplus electricity from solar power generation or wind power generation.

[0036] The reaction apparatus 1 of this embodiment shown in FIG. 6 includes a reaction furnace 3 having a methane gas supply port 12, a CO2 supply port 14, a hydrogen gas exhaust port 16, and a CO gas exhaust port 18, a heating device 5 inserted and fixed into the reaction furnace 3 from the top, a structural catalyst 7 having a catalytic effect for a methane thermal decomposition reaction and arranged so as to surround the heating device 5 in the reaction furnace 3, a first on-off valve 9 for controlling the supply of CH4 to the methane gas supply port 12, a second on-off valve 11 for controlling the supply of CO2 to the CO2 supply port 14, a third on-off valve 13 for controlling the discharge of hydrogen from the hydrogen gas exhaust port 16, and a fourth on-off valve 15 for controlling the discharge of CO from the CO gas exhaust port 18.

[0037] The heating device 5 is an internal heating type that is inserted into the reactor 3 and heats from the inside. Specifically, a recuperative burner that uses hydrogen as fuel is used, but biogas may be used as fuel instead. Also, a heater that heats the reactor 3 from the outside (external heating type) can be used.

[0038] The structural catalyst 7 having catalytic activity for the methane thermal decomposition reaction is formed by electrolytically plating, in that order, a copper layer as a copper-containing intermediate layer and a nickel layer as a nickel-containing layer on a nickel plate catalyst as a support layer (structure).

[0039] As the first to fourth on-off valves 9, 11, 13, and 15, gate valves that can be switched between fully open and fully closed are used, but any other valves such as ball valves can be used instead. When flow rate adjustment is particularly required, butterfly valves and globe valves can also be used. Although the on-off valves are switched manually, they may be automatically performed using solenoid valves or the like.

[0040] A desulfurizer 4 for removing trace amounts of sulfur-based compounds contained in the city gas is provided between the CH4 supply source 17 and the first on-off valve 9. As the desulfurizer 4, a conventionally known solid catalyst or adsorbent can be used.

[0041] In this embodiment, the pressure swing adsorption (PSA) method is used as the H2 purification device 6, but instead of this, a purification method based on permeation through a palladium alloy membrane can also be used.

[0042] In this embodiment, a replaceable solid absorbent having a property of absorbing CO2, in which amine is supported on a porous support, is used as the CO purification device 8. However, instead of this, a liquid absorbent, a membrane separation method, or a PSA method can also be used. When the required purity is low, the refining devices 6 and 8 do not need to be provided.

[0043] In this embodiment, a CO detector (not shown) is provided on a flow path connecting the gas exhaust port of the reactor and the fourth on-off valve 15, or on a flow path connecting the fourth on-off valve 15 and the CO purification device 8. The CO detector is an instrument capable of specifically detecting the carbon monoxide concentration or an indicator reflecting the change therein (for example, a change in potential or a change in absorbance). In this embodiment, an NDIR gas sensor is used as the CO detector, but the measurement method is not particularly limited. Also, a detector capable of simultaneously measuring the concentration of gases other than carbon monoxide may be used.

[0044] Compressors 10a and 10b are provided downstream of the refining devices 6 and 8, respectively.

[0045] In actual operation, when the first on-off valve 9 and the third on-off valve 13 are open, the second on-off valve 11 and the fourth on-off valve 15 are closed, and when the second on-off valve 11 and the fourth on-off valve 15 are closed, the first on-off valve 9 and the third on-off valve 13 are closed. The procedure for opening and closing each valve is as follows: close the second on-off valve 11 → close the fourth on-off valve 15 → open the first on-off valve 9 → open the third on-off valve 13 to perform the methane direct decomposition process shown in formula (1), and close the first on-off valve 9 → close the third on-off valve 13 → open the second on-off valve 11 → open the fourth on-off valve 15 to perform the CO2 reduction process shown in formula (2).

[0046] (Experimental Example 1 - Reactor Construction and Methane Pyrolysis) In the reactor 21 shown in FIG. 1, a metal plate catalyst 27 (size: width 30 mm × length 300 mm × thickness 0.6 mm) obtained by electrolytic plating of Cu to a thickness of about 1 μm on both sides of a Ni plate, and then electrolytic plating of Ni to a thickness of about 10 μm was placed in a reactor 23 (capacity Φ30 * 300 mm, 0.2 L) in a state of being suspended from a catalyst suspension stay 24. The reactor 23 was heated by a heater (not shown) provided on the outer periphery of the furnace 23 until the temperature inside the furnace reached 800 ° C. while flowing room temperature methane from a methane supply port 32 provided on the upper part of the peripheral wall of the furnace 23 from top to bottom at 10 mL / min, and was held for 8 hours a day, and the transition of the hydrogen concentration discharged from the hydrogen gas exhaust port 36 was observed. For safety, after 8 hours of continuous operation each day, the core was cooled and heated again from room temperature to 800 ° C. the next day. The time transition of the hydrogen concentration is shown in FIG. 2, and the SEM image of the catalyst with the product attached and the measurement result of EDS are shown in FIG. 3. The temperature inside the furnace was measured using a thermocouple 25 inserted through the top cover of the furnace to reach the center. The hydrogen concentration was measured using a Wheatstone bridge type gas thermal conductivity gas analyzer (zero gas: city gas 13A, span gas: 100% hydrogen, gas flow rate: 0.2L / min, Chino) attached to the generated gas exhaust pipe at the bottom of the furnace peripheral wall. SEM images and EDS were obtained by secondary electron detection using a scanning electron microscope (model number: JCM-7000, JEOL Ltd.) (incident voltage 15.0kV, WD 12.5mm, magnification x5,000, probe current mode Std.-PC, vacuum mode HighVac.). As can be seen from Figure 2, the hydrogen concentration (conversion rate) due to the direct decomposition reaction of methane continued to increase from the first day to the second day, and at the end of the second day the hydrogen concentration reached the theoretical equilibrium concentration of 80%, and thereafter remained stable at around 80% even from the sixth day onwards. From Figure 3, it was found that the product was fibrous and consisted mainly of C and Ni. Furthermore, a separate elemental mapping study revealed that the white dots seen at the tip or in the middle of the fiber were Ni particles.

[0047] (Experimental Example 2 - Demonstration of the Boudouard reaction with residual carbon produced and examination of the implementation temperature) After the experiment of Example 1, the supply of methane was stopped and the weight of the carbon produced in the reactor was measured. After measuring the weight of the carbon produced, the metal catalyst plate with the carbon produced and the carbon produced were returned to the reactor. At that time, in order to remove the air that had entered the reactor, room temperature nitrogen gas was filled into the reactor at a flow rate of 0.4 L / min for 30 minutes to purge the air remaining in the reactor. Next, instead of stopping the nitrogen gas supply, room temperature CO2 was supplied at a flow rate of 0.4 L / min while heating until the temperature inside the furnace reached a constant heater temperature, and the CO and CO2 concentration levels were measured until they reached equilibrium. The relationship between the furnace temperature and the equilibrium concentration levels of CO and CO2 is shown in Figure 4. The concentrations of CO and CO2 at this time were measured by sampling the generated gas from the exhaust pipe that releases into the atmosphere, installed at the bottom end of the peripheral wall of the furnace, and using an NDIR gas sensor (gas flow rate: 0.5 L / min, manufactured by AWIT). As can be seen from Figure 4, as the heater temperature increased from 400°C to 800°C, CO increased from 0% to nearly 85%, while CO2 decreased from 100% to 15%. The equilibrium concentration at 800°C is C + CO2⇔2CO The theoretical concentration is 87% (RTlnK = -ΔG°, ΔG° = -17.5 kJ mol -1 This is close to the fundamental characteristics of a molten carbonate direct carbon fuel cell using a cylindrical cell, and suggests that the Boudouard reaction occurs, in which the carbon produced on the catalyst reacts with CO2 to produce CO.

[0048] (Experimental Example 3 - Changes in Boudouard reaction over time) In Example 1, the supply of methane was stopped, and the reaction furnace with the metal catalyst plate to which the produced carbon was attached still in place was filled with room temperature nitrogen gas at a flow rate of 0.4 L / min for 30 minutes to purge the methane and hydrogen remaining in the furnace. Next, the supply of nitrogen gas was stopped and room temperature CO2 was supplied into the furnace at a flow rate of 0.4 L / min. The moment when nitrogen was switched to CO2 was set as 0 seconds, and the time-dependent changes in the CO and CO2 concentration levels were observed in seconds. The results are shown in Figure 5. As can be seen from Figure 5, reduction began 22 seconds after switching from nitrogen to CO2, and the CO concentration stabilized at 83% 1 minute 41 seconds later. From this, it is believed that although there was a drop in temperature when CO2 was first introduced, the temperature inside the furnace soon returned to around 800°C, causing CO reduction to progress rapidly, and the concentration of the supplied CO2 was converted to CO with almost no increase. In this state, it is believed that there was still enough carbon produced in the furnace to reduce the CO2.

[0049] The present invention is not limited to the above-described embodiment, and not all of the configurations described in the above-described embodiment are essential requirements for the present invention. The present invention may be modified in various ways within the scope of the technical concept of the present invention.

[0050] In an alternative embodiment, a pipe may be provided between the purification device 6 and the compressor 10a for returning the raw gas methane separated in the purification device 6 to the reactor 3 or the methane supply port 12, and a pipe may be provided between the purification device 8 and the compressor 10b for returning the raw gas CO2 separated in the purification device 8 to the reactor 3 or the CO2 supply port 14.

[0051] In an alternative embodiment, a compressor may also be provided upstream of the purification devices 6, 8 (closer to the gas outlet).

[0052] In an alternative embodiment, a main valve capable of releasing the gas remaining in the reactor into the atmosphere or a main valve for releasing the gas into a flow path separate from each flow path of the generated gas may be provided at a position closer to the gas outlet of the reactor than the third and fourth on-off valves. Purging the main valve using the raw material gas can improve the purity of the generated gas managed by the third and fourth on-off valves downstream of the main valve.

[0053] In another alternative embodiment, the number of gas supply inlets and gas exhaust outlets may be reduced to one each, and the flow paths from the gas supply inlets to the supply sources of each raw material gas and the flow paths from the gas exhaust outlet to the third and fourth on-off valves may be unified partway through. A configuration may also be adopted in which one supply-side three-way valve is used in place of the first and second on-off valves at each branch point, and one exhaust-side three-way valve is used in place of the third and fourth on-off valves. [Industrial Applicability]

[0054] The present invention has great industrial applicability because it is suitable for producing useful chemical products using CO2 as a raw material, with little concern about the generation of water in the carbon monoxide or synthesis gas production process. In particular, it is suitable for producing useful chemical products using CO2 as a raw material, such as acetic acid (CH3COOH), acrylic acid (C3H4O2), benzoic acid (C7H6O2), polycarbonate (C 16 H 14 O3) n The present invention is also suitable for on-site production and supply of highly toxic carbon monoxide, and utilization of large amounts of surplus CO2 from CCS. [Explanation of symbols]

[0055] 1, 21 Reactor 3. 23 Reactor 4 Desulfurizer 5 Heating device 6 H2 purification equipment 7, 27 Structure catalyst 8. CO purification equipment 9 First opening and closing valve 10a, 10b Compressor 11 Second opening and closing valve 12, 32 Methane supply port 13 Third opening and closing valve 14, 34 CO2 supply port 15 Fourth opening and closing valve 16, 36 Hydrogen gas outlet 17 CH4 source 18, 38 CO gas outlet 19 CO2 source 24 Catalyst suspension stay 25 Thermocouple

Claims

1. A method for producing carbon monoxide or carbon monoxide and hydrogen, comprising sequentially carrying out reactions represented by the following formulas (1) and (2) in a substantially anhydrous environment: <h2 style=";text-align:left;direction:ltr">CH<h2 style=";text-align:left;direction:ltr"> ４ <h2 style=";text-align:left;direction:ltr"> →C+2H<h2 style=";text-align:left;direction:ltr"> ２ <h2 style=";text-align:left;direction:ltr">・・・・(1) C+CO ２ →2CO・・・・(2)

2. Carbon Dioxide (CO ２ ) using carbon dioxide capture and storage (CCS) technology ２ The method according to claim 1, wherein

3. 2. The method according to claim 1, wherein the reaction of formula (1) is carried out using a catalyst having a catalytic effect on a methane thermal decomposition reaction, and the reaction of formula (2) is carried out in the presence of carbon produced in the reaction of formula (1).

4. A method for producing a synthesis gas or a chemical product using the same, comprising mixing the hydrogen obtained by the method according to claim 1 and carbon monoxide in a constant ratio by adjusting the molar flow rates.

5. In addition, hydrogen derived from renewable energy sources is added to ２ The method for producing a synthesis gas or a chemical product using the same according to claim 4, further comprising adjusting the ratio of H2O to CO.

6. A reaction apparatus comprising a reactor housing a structural catalyst having a catalytic effect for a methane thermal decomposition reaction, and a CO detector on a flow path connected to a gas exhaust port of the reactor.

7. 7. The apparatus according to claim 6, wherein the reactor comprises one gas supply port and one gas exhaust port, and further comprises a supply-side three-way valve for switching a supply path to the gas supply port, and a exhaust-side three-way valve for switching a exhaust path from the gas exhaust port.

8. 7. The apparatus according to claim 6, further comprising a discharge side valve for controlling discharge of hydrogen and / or CO from the reactor, and a main valve capable of releasing gas remaining in the reactor into the atmosphere, or a main valve capable of releasing the gas to a flow path separate from each flow path of hydrogen and CO, provided at a position closer to a gas exhaust port of the reactor than the discharge side valve.

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