Energy utilization system and method for producing carbon-containing material

Abstract

To provide an energy utilization system that can yield a carbon-containing material by reducing carbon dioxide while suppressing emission of carbon dioxide, and to provide a method for manufacturing the carbon-containing material.SOLUTION: An energy utilization system (1) of the invention comprises: a heat utilization cycle (30) in which a heat medium circulates, incorporating a high-temperature utilization heat exchange section (36) that adjusts the temperature of the heat medium by utilizing renewable energy or energy obtained from exhaust heat; and an electrolytic reduction device (70) that electrolytically reduces an electrolyte having dissolved carbon dioxide. The electrolytic reduction device (70) performs an electrolytic reduction of an electrolyte having a temperature adjusted by thermal contact with the heat medium, and the electrolytic reduction device (70) has: a cylindrical electrolytic cell casing (79) extending in a first direction; an anode (71) provided inside the electrolytic cell casing (79) and extending in the first direction; a cylindrical cathode (72) positioned inside the electrolytic cell casing (79) and outside the anode (71) as viewed in the first direction, and extending in the first direction; and an electrolyte flow path (73) through which the electrolyte flows in the first direction between the anode (71) and the cathode (72).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an energy utilization system and a method for producing a carbon-containing material. [Background technology]

[0002] 2. Description of the Related Art In recent years, from the viewpoint of reducing carbon dioxide and other substances as a measure against global warming, there has been progress in the development of carbon recycling technology, which involves obtaining carbon compounds and the like by reducing carbon dioxide and reusing them.

[0003] For example, Patent Document 1 (JP 2016-89230 A) proposes producing a carbon material by electrolytic reduction of carbon dioxide in a sealed reaction vessel. In addition, for example, Patent Document 2 (JP 2023-15104 A) proposes producing carbon monoxide and various organic compounds (hydrocarbons, ethers, cyclic ethers, alcohols, or carbonyl compounds) by similarly electrolytic reduction of carbon dioxide. Summary of the Invention [Problem to be solved by the invention]

[0004] Here, in order to produce a carbon-containing material from carbon dioxide with the aim of reducing carbon dioxide, it is desirable to efficiently electrolytically reduce carbon dioxide while suppressing the use of energy that would increase carbon dioxide. [Means for solving the problem]

[0005] The energy utilization system according to a first aspect includes a circulation circuit and an electrolytic reduction device. The circulation circuit has a temperature adjustment unit. A heat medium circulates through the circulation circuit. The temperature adjustment unit adjusts the temperature of the heat medium by utilizing renewable energy or energy obtained from exhaust heat. The electrolytic reduction device electrolytically reduces an electrolyte having carbon dioxide dissolved therein. The electrolytic reduction device electrolytically reduces an electrolyte whose temperature has been adjusted by thermal contact with the heat medium. The electrolytic reduction device has a casing, a first electrode, a second electrode, and an electrolyte flow path. The casing is cylindrical and extends in a first direction. The first electrode is provided inside the casing and extends in the first direction. The second electrode is cylindrical and extends in the first direction. The second electrode is located inside the casing and outside the first electrode when viewed in the first direction. The electrolyte flow path causes the electrolyte to flow in the first direction between the first electrode and the second electrode.

[0006] Here, the renewable energy may be, for example, energy obtained by one or more selected from the group consisting of solar power generation, wind power generation, hydroelectric power generation, biomass power generation, geothermal power generation, tidal power generation, hydrogen combustion power generation, and ammonia combustion power generation. This renewable energy may be unstable in that the amount of energy obtained is not constant depending on the time of day, etc., compared to energy such as electricity supplied through major power networks operated by power companies.

[0007] Here, the waste heat is not particularly limited, and examples thereof include heat discharged from thermal power plants, nuclear power plants, chemical plants, refineries, waste incineration plants, geothermal energy, hot spring water, and the like.

[0008] According to this energy utilization system, the temperature of the heat medium is adjusted by utilizing the energy obtained by renewable energy or exhaust heat. The temperature-adjusted heat medium circulates through the circulation circuit and thermally contacts with the electrolyte to adjust the temperature of the electrolyte in which carbon dioxide is dissolved. This improves the reduction efficiency of the electrolyte. Moreover, in the electrolyte flow path of the electrolytic reduction device, the electrolyte flows in the first direction between the first electrode and the second electrode. This makes it possible to perform electrolytic reduction of the electrolyte while continuing to supply the electrolyte between the first electrode and the second electrode. This also makes it possible to increase the reduction efficiency of the electrolyte in that it is easy to maintain a high concentration of carbon dioxide or carbonate ions in the electrolyte near the first electrode and the second electrode. Furthermore, in the electrolytic reduction of carbon dioxide, the temperature of the electrolyte can be adjusted using the heat medium whose temperature is adjusted by utilizing the energy obtained by renewable energy or exhaust heat, so that it is possible to reduce carbon dioxide while suppressing carbon dioxide emissions.

[0009] An energy utilization system according to a second aspect is the energy utilization system according to the first aspect, wherein the first electrode is an anode and the second electrode is a cathode.

[0010] In this energy utilization system, carbon dioxide can be reduced in the cathode that is provided outside the anode when viewed in the first direction. Therefore, compared to when the cathode is provided inside the anode, when the cathode is provided outside the anode, a larger surface area of ​​the cathode can be secured, and carbon dioxide can be reduced more efficiently.

[0011] A third aspect of the energy utilization system is the energy utilization system according to the second aspect, wherein the anode is tubular and extends in a first direction. The electrolytic reduction device has a first gas flow path. The first gas flow path is provided inside the anode when viewed in the first direction, and allows gas generated by an oxidation reaction of the electrolytic solution to pass through.

[0012] In this energy utilization system, gas generated by the oxidation reaction of the electrolyte is prevented from accumulating on the spot and is sent in the first direction, thereby making it possible to increase the efficiency of the oxidation reaction at the anode.

[0013] An energy utilization system according to a fourth aspect is the energy utilization system according to the third aspect, wherein the anode has an anode catalyst layer and an anode gas diffusion layer. The anode catalyst layer is cylindrical and extends in a first direction. The anode gas diffusion layer is provided inside the anode catalyst layer and outside the first gas flow path when viewed in the first direction. The anode gas diffusion layer is cylindrical and extends in the first direction.

[0014] In this energy utilization system, the oxidation reaction at the anode can be carried out efficiently.

[0015] In a fifth aspect of the energy utilization system, in the energy utilization system according to any one of the second to fourth aspects, the electrolytic reduction device has a second gas flow path. The second gas flow path is provided outside the cathode and inside the casing when viewed in the first direction, and allows gas generated by a reduction reaction of the electrolytic solution to pass through.

[0016] In this energy utilization system, gas generated by the reduction reaction of the electrolyte is prevented from accumulating on the spot and is sent in the first direction, thereby making it possible to increase the efficiency of the reduction reaction at the cathode.

[0017] An energy utilization system according to a sixth aspect is the energy utilization system according to the fifth aspect, wherein the cathode has a cathode catalyst layer and a cathode gas diffusion layer. The cathode catalyst layer is cylindrical and extends in a first direction. The cathode gas diffusion layer is cylindrical and extends in the first direction. The cathode gas diffusion layer is provided outside the cathode catalyst layer and inside the second gas flow path when viewed in the first direction.

[0018] In this energy utilization system, the reduction reaction at the cathode can be carried out efficiently.

[0019] An energy utilization system according to a seventh aspect is the energy utilization system according to any one of the first to sixth aspects, further comprising a heat pump. The heat pump is driven by using electric power generated from renewable energy. A first refrigerant circulates through the heat pump. The temperature adjustment unit adjusts the temperature of the heat medium by heat of the first refrigerant whose temperature has been adjusted by the heat pump.

[0020] In this energy utilization system, the heat pump is driven using electricity generated from renewable energy, so that the environmental load associated with driving the heat pump can be reduced.

[0021] An energy utilization system according to an eighth aspect is the energy utilization system according to any one of the first to seventh aspects, further comprising a heat engine. The heat engine generates electricity by utilizing heat from the heat medium. The electrolytic reduction device applies a voltage to the electrolyte by utilizing the electricity generated by the heat engine.

[0022] In this energy utilization system, the heat of the heat medium that is not used to adjust the temperature of the electrolyte is utilized to generate power, and the voltage obtained can be used for electrolytic reduction.

[0023] An energy utilization system according to a ninth aspect is the energy utilization system according to any one of the first to eighth aspects, wherein the circulation circuit has a storage unit. The storage unit stores heat of the heat medium as stored energy.

[0024] In this energy utilization system, even if the supply of renewable energy or exhaust heat is unstable, the instability can be alleviated by storing the heat of the heat medium as stored energy.

[0025] Even if the temperature of the heat medium flowing through the circulation circuit fluctuates due to instability in the energy obtained from renewable energy or exhaust heat, the temperature fluctuation can be leveled out and high-quality heat energy can be used. Therefore, the temperature of the electrolyte to be electrolytically reduced can be adjusted to a temperature at which electrolytic reduction can proceed efficiently.

[0026] A method for producing a carbon-containing material according to a tenth aspect includes a step of adjusting the temperature of a heat medium circulating in a circulation circuit by utilizing renewable energy or energy obtained from exhaust heat, a step of adjusting the temperature of an electrolytic solution, and a step of electrolytically reducing the temperature-adjusted electrolytic solution. The electrolytic solution to be temperature-adjusted is an electrolytic solution in which carbon dioxide is dissolved. The electrolytic solution is temperature-adjusted by being thermally contacted with the heat medium. In the electrolytically reducing step, the electrolytic solution flows in a first direction between a first electrode extending in a first direction and a cylindrical second electrode extending in the first direction so as to surround the first electrode when viewed in the first direction.

[0027] Here, the renewable energy may be, for example, energy obtained by one or more selected from the group consisting of solar power generation, wind power generation, hydroelectric power generation, biomass power generation, geothermal power generation, tidal power generation, hydrogen combustion power generation, and ammonia combustion power generation. This renewable energy may be unstable in that the amount of energy obtained is not constant depending on the time of day, etc., compared to energy such as electricity supplied through major power networks operated by power companies.

[0028] Here, the waste heat is not particularly limited, and examples thereof include heat discharged from thermal power plants, nuclear power plants, chemical plants, refineries, waste incineration plants, geothermal energy, hot spring water, and the like.

[0029] In this method for producing a carbon-containing material, the temperature of the heat medium is adjusted using energy obtained from renewable energy or exhaust heat. The temperature-adjusted heat medium circulates through a circulation circuit and thermally contacts the electrolyte to adjust the temperature of the electrolyte in which carbon dioxide is dissolved. This improves the reduction efficiency of the electrolyte. In addition, the electrolytic reduction is performed while the electrolyte is flowing between the first electrode and the second electrode in the first direction. This makes it possible to perform the electrolytic reduction of the electrolyte while continuing to supply the electrolyte between the first electrode and the second electrode. This also makes it possible to increase the reduction efficiency of the electrolyte in that it is easy to maintain a high concentration of carbon dioxide or carbonate ions in the electrolyte near the first electrode and the second electrode. Furthermore, in the electrolytic reduction of carbon dioxide, the temperature of the electrolyte is adjusted using a heat medium whose temperature is adjusted using energy obtained from renewable energy or exhaust heat, so that it is possible to reduce carbon dioxide while suppressing carbon dioxide emissions.

[0030] A method for producing a carbon-containing material according to an eleventh aspect is the method for producing a carbon-containing material according to the tenth aspect, wherein the first electrode is an anode and the second electrode is a cathode.

[0031] In this method for producing a carbon-containing material, carbon dioxide can be reduced in the cathode that is provided outside the anode when viewed in the first direction. Therefore, compared to when the cathode is provided inside the anode, when the cathode is provided outside the anode, a larger surface area of ​​the cathode can be secured, and carbon dioxide can be reduced more efficiently.

[0032] A twelfth aspect of the present invention relates to a method for producing a carbon-containing material, and in the method for producing a carbon-containing material according to the tenth or eleventh aspect, the temperature of the heat medium is adjusted by heat of a first refrigerant using a heat pump in which the first refrigerant circulates. The heat pump is driven by electricity generated by renewable energy.

[0033] In this method for producing a carbon-containing material, the heat pump is driven using electricity generated from renewable energy, thereby reducing the environmental load associated with driving the heat pump.

[0034] A method for producing a carbon-containing material according to a thirteenth aspect is the method for producing a carbon-containing material according to any one of the tenth to twelfth aspects, further comprising the step of generating electricity in a heat engine by utilizing heat from the heat medium. In the electrolytic reduction step, a voltage is applied to the electrolyte by utilizing the electricity generated by the heat engine.

[0035] In this method for producing a carbon-containing material, the heat of the heat medium that is not used to adjust the temperature of the electrolyte is utilized to generate electricity, and the electricity can be used for electrolytic reduction.

[0036] A fourteenth aspect of the present invention relates to a method for producing a carbon-containing material, in the thirteenth aspect, wherein the circulation circuit has a storage section that stores the heat of the heat medium as stored energy.

[0037] In this method for producing a carbon-containing material, even if the supply of renewable energy or exhaust heat is unstable, the instability can be alleviated by storing the heat of the heat medium as stored energy.

[0038] Even if the temperature of the heat medium flowing through the circulation circuit fluctuates due to instability in the energy obtained from renewable energy or exhaust heat, the temperature fluctuation can be leveled out and high-quality heat energy can be used. Therefore, the temperature of the electrolyte to be electrolytically reduced can be adjusted to a temperature at which electrolytic reduction can proceed efficiently.

[0039] The electrolytic reduction device according to Appendix 1 is an electrolytic reduction device that performs electrolytic reduction of an electrolyte solution having carbon dioxide dissolved therein, and includes a cylindrical casing extending in a first direction, an anode provided inside the casing and extending in the first direction, a cylindrical cathode located inside the casing and outside the anode when viewed in the first direction, and extending in the first direction, and an electrolyte flow path that allows the electrolyte to flow in the first direction between the anode and the cathode. [Brief description of the drawings]

[0040] [Figure 1] 1 is a schematic configuration diagram of an energy utilization system according to a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram of a carbon dioxide treatment device. [Diagram 3] FIG. 2 is a partial cross-sectional view of the electrolytic reduction device as viewed in the longitudinal direction. [Figure 4] FIG. 1 is a schematic configuration diagram of a network used in a microgrid system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] The energy utilization system and the material manufacturing method according to this embodiment will be described below with reference to examples.

[0042] (1) First embodiment The energy utilization system 1 is a system that uses renewable energy to obtain thermal energy, electricity, and carbon-containing materials and utilizes them, and as shown in FIG. 1, is equipped with a heat pump 10, a heat engine 20, a heat utilization cycle 30, and a carbon dioxide treatment device 40.

[0043] (1-1) Heat pump The heat pump 10 includes a first refrigerant circuit 11 filled with a first refrigerant. Examples of the first refrigerant that can be used include R1233zd(E), R1234yf, R1234ze(E), R1234ze(Z), R134a, R32, R410a, R245fa, water, and carbon dioxide. These first refrigerants can improve the efficiency of the operation of the heat pump 10 when heating the heat medium to a temperature range below 200°C. The first refrigerant circuit 11 includes a first compressor 12, a first high-temperature heat exchanger 13, an expansion valve 15, a first low-temperature heat exchanger 16, and a first intermediate heat exchanger 14.

[0044] The first compressor 12 uses renewable energy supplied via a renewable energy supply unit 91 as a power source. For driving control of the heat pump 10, only the renewable energy supplied via the renewable energy supply unit 91 may be used as a power source, or both the renewable energy and power supplied from a power company may be used as power sources. When both renewable energy and power supplied from a power company are used, it is preferable that the amount of power from the renewable energy is used more than the amount of power supplied from the power company.

[0045] Renewable energy is energy obtained, for example, from solar power generation, wind power generation, hydroelectric power generation, biomass power generation, geothermal power generation, tidal power generation, hydrogen combustion power generation, ammonia combustion power generation, etc., and among these, solar power generation, wind power generation, and geothermal power generation are preferred because they allow for relatively steady power generation and also reduce the amount of carbon dioxide emitted.

[0046] The first high-temperature heat exchanger 13 heats the first heat medium and cools the first refrigerant by performing heat exchange between the first refrigerant flowing through the first high-temperature heat exchanger 13 and the first heat medium flowing through the high-temperature utilization heat exchange section 36 of the heat utilization cycle 30 without mixing with each other. The first refrigerant that has passed through the first high-temperature heat exchanger 13 is sent to the first intermediate heat exchange section 14a, and is heat exchanged with the first refrigerant flowing through the first intermediate heat exchanger 14 without mixing with each other. The first refrigerant that has passed through the first intermediate heat exchange section 14a is reduced in pressure in the expansion valve 15 and sent to the first low-temperature heat exchanger 16.

[0047] In the first low-temperature heat exchanger 16, heat is exchanged between the first refrigerant flowing through the first low-temperature heat exchanger 16 and the exhaust gas flowing through the exhaust heat supply unit 92, thereby heating the first refrigerant and cooling the exhaust gas. Note that the exhaust heat supply unit 92 may use high-temperature exhaust gas containing a large amount of carbon dioxide at a temperature of 80° C. or more and 120° C. or less, such as combustion gas used in a factory, etc. Note that the amount of thermal energy of the exhaust heat supplied to the exhaust heat supply unit 92 is adjusted by an exhaust gas transport means (not shown).

[0048] The first refrigerant that has passed through the first low-temperature heat exchanger 16 is sent to the first intermediate heat exchanger 14. In the first intermediate heat exchanger 14, as described above, the first refrigerant flowing through the first intermediate heat exchanger 14 is heated by the first refrigerant flowing through the first intermediate heat exchange section 14a. The first refrigerant that has passed through the first intermediate heat exchanger 14 is sucked into the first compressor 12.

[0049] (1-2) Heat Engine The heat engine 20 includes a second refrigerant circuit 21 filled with a second refrigerant. As the second refrigerant, for example, R1233zd(E), R1234yf, R1234ze(E), R1234ze(Z), R134a, R32, R410a, R245fa, water, carbon dioxide, etc. can be used.

[0050] The second refrigerant circuit 21 has a second pump 22, a second high-temperature heat exchange section 23, an expander 24, a second low-temperature heat exchanger 26, and a second intermediate heat exchanger .

[0051] The second pump 22 forms a flow of the second refrigerant in the second refrigerant circuit 21. The second refrigerant flowing out from the second pump 22 is sent to the second high-temperature heat exchange section 23 via the second intermediate heat exchange section 28a.

[0052] The second high-temperature heat exchange section 23 heats the second refrigerant and cools the first heat medium by performing heat exchange between the second refrigerant flowing through the second high-temperature heat exchange section 23 and the first heat medium flowing through the low-temperature utilization heat exchanger 34 of the heat utilization cycle 30 without mixing with each other. The second refrigerant that has passed through the second high-temperature heat exchange section 23 is sent to the expander 24. The second refrigerant sent to the expander 24 is depressurized and sent to the second intermediate heat exchanger 28. The expander 24 generates electricity using energy recovered when the second refrigerant is depressurized. The electricity generated by the expander 24 can be used as a power source for the first compressor 12 of the heat pump 10, a power source for a voltage applied to the electrolytic reduction device 70, etc.

[0053] In the second intermediate heat exchanger 28, heat exchange is performed between the second refrigerant flowing through the second intermediate heat exchanger 28 and the second refrigerant flowing through the second intermediate heat exchange section 28a flowing from the second pump 22 toward the second high-temperature heat exchange section 23, without the refrigerants being mixed with each other. The second low-temperature heat exchanger 26 exchanges heat between the second refrigerant flowing through the second low-temperature heat exchanger 26 and air supplied from outdoors via the second refrigerant cooling section 93. The second refrigerant that has passed through the second low-temperature heat exchanger 26 is sent to the second pump 22.

[0054] (1-3) Heat Utilization Cycle The heat utilization cycle 30 includes a heat utilization circuit 31 filled with a heat medium. As the heat medium, for example, a mixed fluid containing sand or rock and air, water, thermal oil, ionic liquid, latent heat storage material such as molten salt, etc. can be used from the viewpoint of enabling storage of high-temperature thermal energy. The heat utilization circuit 31 includes a heat medium pump 32, an electrolytic reduction temperature adjustment unit 33, a low-temperature utilization heat exchanger 34, a pressurizing line 38, a low-temperature tank 35, a high-temperature utilization heat exchange unit 36, and a high-temperature tank 37.

[0055] The heat medium pump 32 generates a flow that circulates the heat medium in the heat utilization cycle 30. The heat medium that has passed through the heat medium pump 32 is sent to the electrolytic reduction temperature adjustment unit 33. The electrolytic reduction temperature adjustment unit 33 passes through a constant temperature bath 33x in a constant temperature container 70x of the electrolytic reduction device 70 described below. The constant temperature bath 33x is filled with a heat retention medium. The heat medium heats the heat retention medium in the constant temperature bath 33x. The heat retention medium heats the electrolytic solution in the electrolytic solution casing 79. The heat medium sent to the electrolytic reduction temperature adjustment unit 33 adjusts the temperature of the electrolytic solution by, for example, heating the electrolytic solution to be electrolytically reduced in the electrolytic reduction device 70.

[0056] The heat medium that has passed through the electrolytic reduction temperature adjustment unit 33 is sent to the low-temperature utilization heat exchanger 34. A pressurization line 38 for pressurizing and injecting the heat medium into the heat utilization circuit 31 is connected between the electrolytic reduction temperature adjustment unit 33 and the low-temperature utilization heat exchanger 34. The pressurization line 38 is provided with an on-off valve 38a that can be controlled to open and close. The pressurization line 38 pressurizes the heat medium circulating in the heat utilization circuit 31, thereby preventing the heat medium from vaporizing even at high temperatures. For example, when water is used as the heat medium, vaporization is prevented even at temperatures exceeding 100°C.

[0057] The low-temperature utilization heat exchanger 34 heats the second refrigerant and cools the heat medium by performing heat exchange between the heat medium flowing through the low-temperature utilization heat exchanger 34 and the second refrigerant flowing through the second high-temperature heat exchange section 23 of the heat engine 20 without mixing with each other. The heat medium that has passed through the low-temperature utilization heat exchanger 34 is sent to the low-temperature tank 35. The temperature of the heat medium stored in the low-temperature tank 35 is, for example, 80°C or higher and 120°C or lower, and may be 90°C or higher and 110°C or lower. The heat medium that has passed through the low-temperature tank 35 is sent to the high-temperature utilization heat exchange section 36.

[0058] The heat medium flowing through the high-temperature utilization heat exchange section 36 exchanges heat with the first refrigerant flowing through the first high-temperature heat exchanger 13 of the heat pump 10 without mixing with each other, and is heated. The heat medium that has passed through the high-temperature utilization heat exchange section 36 is sent to the high-temperature tank 37. The temperature of the heat medium stored in the high-temperature tank 37 is, for example, 120°C or higher and 150°C or lower, and may be 130°C or higher and 140°C or lower. The heat medium that has passed through the high-temperature tank 37 is sent to the heat medium pump 32.

[0059] It is preferable that both the low temperature tank 35 and the high temperature tank 37 are surrounded by a heat insulating material.

[0060] (1-4) Carbon dioxide treatment device As shown in FIG. 2, the carbon dioxide treatment device 40 is a device for obtaining a carbon-containing material by dissolving carbon dioxide in an electrolyte, recovering the carbon dioxide, heating the electrolyte to an appropriate temperature using a heat medium circulating through the heat utilization cycle 30, and performing electrolytic reduction.

[0061] The carbon dioxide treatment device 40 includes a carbon dioxide recovery device 50, an electrolytic reduction device 70, an electrolyte pump 42, and an electrolyte heat exchanger 43, and is provided with an electrolyte circuit 41 through which the electrolyte circulates.

[0062] The electrolyte pump 42 takes in and sends out the electrolyte, thereby circulating the electrolyte in the electrolyte circuit 41. The electrolyte flowing out from the electrolyte pump 42 is cooled in the electrolyte heat exchanger 43 by heat exchange with a cooling medium such as water or air supplied from an external cooling source to the electrolyte cooling unit 94. The temperature of the cooling medium supplied to the electrolyte cooling unit 94 may be, for example, 15°C or higher and 35°C or lower, and is preferably 20°C or higher and 30°C or lower. The cooled electrolyte is sent to the carbon dioxide capture device 50. Since the electrolyte sent to the carbon dioxide capture device 50 is sufficiently cooled, the carbon dioxide captured in the carbon dioxide capture device 50 is easily dissolved in the electrolyte. The electrolyte in which carbon dioxide is dissolved in the carbon dioxide capture device 50 is sent to the electrolytic reduction device 70. The carbon dioxide contained in the electrolyte sent to the electrolytic reduction device 70 is electrolytically reduced to become a carbon-containing material.

[0063] The electrolyte can be selected from the group consisting of imidazolium-based ionic liquids, aromatic ionic liquids, pyrrolidinium-based ionic liquids, ammonium-based ionic liquids, piperidinium-based ionic liquids, and quaternary phosphonium-based ionic liquids. The electrolyte can be selected from the group consisting of ionic liquids with high solubility of carbon dioxide and low viscosity, or an ionic liquid solution containing an aqueous solution containing additives such as a supporting electrolyte or a basic catalyst. The electrolyte can be selected from the group consisting of electrolytes with a sufficiently wide electrochemical window for the electrolytic reaction of carbon dioxide and water. Examples of ionic liquids constituting such a preferred electrolyte include [BuMePyrr][TFO], [BMIm][TFO], [DEME][BF4], [P2225][TFSI], [BMIM][BF4], [BMIM][TFSI], [PP13][TFSI], and the like. Examples of supporting electrolytes include MCl, M2CO3, MHCO3, MBF4, MPF6, MClO4, MAsF6, MTf, MTFSI, M(CF3SO2)2N, MHPO4 (M=Li, Na, K, Rb, Cs), and the like. Examples of basic catalysts include LiOH, NaOH, KOH, CsOH, Ca(OH)2, and the like. In addition, such an electrolyte is preferable in that it can be operated not only at room temperature but also in a high-temperature environment of 80°C or more and 150°C or less in order to increase efficiency. In addition, such an electrolyte is preferable in that it has a high carbon dioxide absorption capacity and can continuously recover and decompose carbon dioxide. Furthermore, such an electrolyte is liquid at room temperature and has a relatively low vapor pressure, so that there is little loss or dissipation of the electrolyte due to evaporation during operation, and the air sent outside the device does not substantially contain chemical substances derived from the electrolyte other than water vapor, which is also preferable.

[0064] (1-4-1) Carbon dioxide capture equipment The carbon dioxide capture device 50 is a device that captures carbon dioxide supplied from the outside via a carbon dioxide supply line 81 and dissolves it in an electrolytic solution. The carbon dioxide supply line 81 is a flow path for capturing carbon dioxide from exhaust gas containing a large amount of carbon dioxide, such as combustion gas used in a factory. In this embodiment, not only carbon dioxide but also gas containing moisture flows through the carbon dioxide supply line 81, and the gas is supplied to the carbon dioxide capture device 50. In this case, the gas may be ambient air containing a low concentration of carbon dioxide. The amount of carbon dioxide supplied to the carbon dioxide supply line 81 is adjusted by a carbon dioxide transport means (not shown).

[0065] The carbon dioxide capture device 50 has a plurality of absorption flow paths 51 through which the electrolyte passes, a plurality of carbon dioxide flow paths 52 through which carbon dioxide supplied from a carbon dioxide supply line 81 passes, and hollow fiber membranes 53 provided between each absorption flow path 51 and each carbon dioxide flow path 52.

[0066] In the carbon dioxide capture device 50, the direction in which the electrolyte flows through the absorption flow path 51 and the direction in which carbon dioxide flows through the carbon dioxide flow path 52 are configured to be opposite to each other. This allows the electrolyte to take in more carbon dioxide that has passed through the hollow fiber membrane 53 as it progresses through the absorption flow path 51. Note that the electrolyte containing carbon dioxide may be an electrolyte having carbon dioxide gas dissolved therein, an electrolyte having carbonate ions or bicarbonate ions, or an electrolyte having carbon dioxide gas dissolved therein and having carbonate ions or bicarbonate ions.

[0067] The electrolyte that has absorbed a large amount of carbon dioxide flows through the electrolyte circuit 41 and is supplied to the electrolytic reduction device 70. Meanwhile, on the downstream side of the carbon dioxide flow path 52, clean air with a reduced carbon dioxide concentration is collected in an air outlet line 82 and sent out to the outside of the carbon dioxide capture device 50.

[0068] (1-4-2) Electrolytic reduction device The electrolytic reduction device 70 is a device that obtains a carbon-containing material by electrolytic reduction of an electrolyte solution containing carbon dioxide. Note that the electrolytic reduction device 70 of the present embodiment preferably does not use a solid electrolyte membrane.

[0069] As shown in FIG. 2 and FIG. 3, which is a cross-sectional view of the SS section in FIG. 2, the electrolytic reduction device 70 has an electrolytic cell casing 79, a thermostatic cell 33x, a thermostatic container 70x, an anode 71, a cathode 72, an electrolyte flow path 73, a first recovery path 83, and a second recovery path 84.

[0070] An electrolytic solution containing carbon dioxide passes through the electrolytic cell casing 79. The electrolytic cell casing 79 is configured in a substantially cylindrical shape with the passage of the electrolytic solution in the longitudinal direction, which is the axial direction. The interior of the electrolytic cell casing 79 has an upstream region 77 to which the electrolytic solution that has flowed out of the carbon dioxide capture device 50 is supplied, and a downstream region 78 through which the electrolytic solution that has been electrolytically reduced passes before flowing out of the electrolytic cell casing 79.

[0071] The thermostatic container 70x is a container that houses the electrolytic cell casing 79, the thermostatic bath 33x, and the electrolytic reduction temperature adjustment unit 33 in the heat utilization cycle 30. The thermostatic bath 33x is configured by filling the inside of the thermostatic container 70x and the outside of the electrolytic cell casing 79 with a heat retention medium. The heat retention medium is not particularly limited and may be water, metal, or the like. The heat retention medium of the thermostatic bath 33x is heated by heat exchange with the heat medium flowing through the electrolytic reduction temperature adjustment unit 33 in the heat utilization cycle 30. The heated heat retention medium heats the electrolytic solution inside the electrolytic cell casing 79 by thermally contacting the electrolytic cell casing 79. As a result, the temperature of the electrolytic solution is adjusted to a temperature at which electrolytic reduction can be efficiently performed.

[0072] The anode 71 is provided inside the electrolytic cell casing 79 near the center of the electrolytic cell casing 79 as viewed in the longitudinal direction. The anode 71 extends along the longitudinal direction of the electrolytic cell casing 79 between the upstream region 77 and the downstream region 78 of the electrolytic cell casing 79. An anode recovery passage 71x is provided radially inside the anode 71 as viewed in the longitudinal direction of the electrolytic cell casing 79. The anode 71 has an anode gas diffusion layer 71b provided radially outside the anode recovery passage 71x and having a cylindrical shape, and an anode catalyst layer 71a provided radially outside the anode gas diffusion layer 71b and having a cylindrical shape. The anode recovery passage 71x, the anode gas diffusion layer 71b, and the anode catalyst layer 71a all extend along the longitudinal direction of the electrolytic cell casing 79. The anode recovery path 71x radially penetrates a part of the electrolyte flow path 73 and a part of the cathode 72, and further has a part that extends radially outward so as to radially penetrate a frame part of the electrolytic cell casing 79, thereby being connected to the anode connection part 71c. The anode connection part 71c is connected to a first recovery path 83. The position of the anode connection part 71c is not particularly limited, and may be located, for example, on the upstream side of the electrolytic cell casing 79.

[0073] At the anode 71, a water oxidation reaction occurs as shown in the following formula (1), producing oxygen and hydrogen ions. 2H2O→4H + +O2+4e - (1)

[0074] As the anode catalyst layer 71a, from the viewpoints of generating an oxidation reaction product at a high current density, being stable against oxidation reactions, and easily securing a large surface area, it is preferable to use silver fine particles, platinum mesh, porous nickel, carbon felt, etc.

[0075] For the anode gas diffusion layer 71b, graphite or the like can be preferably used from the viewpoints of bonding with the catalyst layer with high strength, high electrical conductivity, small and uniform particles, and excellent isotropy.

[0076] The cathode 72 is provided in a tubular shape on the outside away from the outer periphery of the anode 71 and inside the outer frame of the electrolytic cell casing 79 as viewed in the longitudinal direction of the electrolytic cell casing 79. The cathode 72 extends in a cylindrical shape along the longitudinal direction of the electrolytic cell casing 79 between an upstream region 77 and a downstream region 78 in the electrolytic cell casing 79. The cathode 72 has a cathode catalyst layer 72a constituting an inner circumferential portion of the cathode 72, and a cathode gas diffusion layer 72b provided in a cylindrical shape radially outside the cathode catalyst layer 72a. As viewed in the longitudinal direction of the electrolytic cell casing 79, a cathode recovery channel 72x is provided on the radially outer side of the cathode 72, radially outside the cathode gas diffusion layer 72b and in a cylindrical shape inside the frame of the electrolytic cell casing 79. The cathode catalyst layer 72a, the cathode gas diffusion layer 72b, and the cathode recovery channel 72x all extend along the longitudinal direction of the electrolytic cell casing 79. The cathode recovery channel 72x penetrates the frame portion of the electrolytic cell casing 79 radially outward and is connected to the cathode connecting portion 72c. The cathode connecting portion 72c is connected to the second recovery channel 84. The position of the cathode connecting portion 72c is not particularly limited, and may be located, for example, on the downstream side of the electrolytic cell casing 79.

[0077] A reduction reaction of carbon dioxide occurs at the cathode 72. Specifically, as shown in the following formula (2), carbon dioxide reacts with hydrogen ions and electrons to produce carbon monoxide and water, which are carbon-containing substances. Hydrogen may also be produced depending on the electrolysis conditions. 2CO2+4H + +4e - →2CO+2H2O (2)

[0078] As the cathode catalyst layer 72a, for example, a composite material film containing a high proportion of Cu nanocrystals having a (100) face can be preferably used.

[0079] For the cathode gas diffusion layer 72b, graphite or the like can be preferably used from the viewpoints of being bonded to the catalyst layer with high strength, having high electrical conductivity, having small and uniform particles, and having excellent isotropy.

[0080] In this embodiment, the cathode 72 is provided in a cylindrical shape radially outside the anode 71, and therefore a structure can be achieved in which the surface area where the reduction reaction occurs in the cathode 72 is more likely to be secured than the surface area where the oxidation reaction occurs in the anode 71. This makes it possible to efficiently obtain carbon-containing materials obtained by reducing carbon dioxide.

[0081] The electrolyte flow path 73 is a tubular portion provided outside the anode 71 and inside the cathode 72 when viewed in the longitudinal direction of the electrolytic cell casing 79, and is a cylindrical portion through which the electrolyte flows along the longitudinal direction of the electrolytic cell casing 79. When the electrolyte passes through the electrolyte flow path 73, a voltage is applied to the anode 71 and the cathode 72, so that the electrolyte is electrolyzed. In the electrolyte flow path 73, the flow formed by the electrolyte pump 42 allows the electrolyte that has not been electrolyzed to be continuously supplied to the electrolyte flow path 73, and the electrolyte that has been electrolyzed to be discharged from the electrolyte flow path 73. This enables efficient electrolytic reduction.

[0082] The first recovery path 83 is connected to the anode connection portion 71c, and is a flow path that sends and recovers to the outside the substances generated by electrolysis of the electrolytic solution in the anode 71. An opening / closing valve 83a is provided in the middle of the first recovery path 83. Note that the first recovery path 83 may be provided with a decompression pump (not shown) or the like as necessary, making it possible to recover reaction products and the like.

[0083] The second recovery path 84 is connected to the cathode connecting portion 72c, and is a flow path for sending and recovering to the outside the substances generated by electrolysis of the electrolytic solution in the cathode 72. An opening / closing valve 84a is provided in the middle of the second recovery path 84. Note that the second recovery path 84 may be provided with a decompression pump (not shown) or the like as necessary, making it possible to recover reaction products and the like.

[0084] As the power of the voltage applied to the anode 71 and the cathode 72 during electrolytic reduction, the power obtained by the expander 24 can be used.

[0085] (1-5) Features of the First Embodiment According to the energy utilization system 1 of this embodiment, the heat pump 10 is driven by renewable energy. Compared to electricity provided by a general power company, the amount of electricity obtained from this renewable energy is not constant depending on the time of day, etc., and there is a risk of the supply amount being unstable. However, the heat pump 10 converts the renewable energy into heat to be stored in the heat utilization cycle 30, making it possible to fully and effectively utilize the renewable energy.

[0086] Furthermore, according to the energy utilization system 1, the heat pump 10 uses the heat stored in the heat utilization cycle 30 to heat the second refrigerant, thereby making it possible to generate power by recovering power in the expander 24. The power obtained in the expander 24 can then be used to apply a voltage to the electrolytic reduction device 70.

[0087] Furthermore, according to the energy utilization system 1, the heat stored in the heat utilization cycle 30 by the heat pump 10 can be used to heat the electrolyte in the electrolytic reduction device 70, and the temperature of the electrolyte can be adjusted. In this embodiment, by heating the electrolyte, it is possible to lower the absolute value of the potential required for electrolytic reduction, and also to increase the conductivity of the electrolyte by reducing its viscosity. These factors make it possible to improve the efficiency of the electrolytic reduction.

[0088] Moreover, in the electrolytic reduction device 70, it is possible to obtain carbon-containing materials using carbon dioxide derived from exhaust gas or dilute carbon dioxide in the atmosphere.

[0089] As a result, it is possible to reduce the environmental load caused by carbon dioxide, effectively utilize renewable energy, and efficiently obtain useful carbon-containing materials derived from carbon dioxide.

[0090] In the present embodiment, in the electrolytic reduction device 70, the cathode 72 is provided in a cylindrical shape radially outside the anode 71, and has a surface area sufficiently larger than that of the anode 71. This makes it possible to efficiently obtain carbon-containing materials obtained by reducing carbon dioxide.

[0091] The electrolytic reduction device 70 is structured so that an electrolytic solution is continuously supplied between the anode 71 and the cathode 72, and the electrolytic solution is continuously discharged. This prevents the surface of the anode 71 from being continuously covered with the product of the reaction, and also prevents the surface of the cathode 72 from being continuously covered with the product of the reaction, making it possible to perform electrolysis continuously and efficiently.

[0092] (2) Other embodiments (2-1) Other embodiment A In the above embodiment, the case where carbon monoxide is obtained as the carbon-containing material has been described as an example.

[0093] In contrast, the carbon-containing material obtainable by reducing carbon dioxide is not particularly limited, and by changing various conditions such as the electrolyte and electrode material, it is possible to obtain, for example, one or more types selected from the group consisting of carbon monoxide, diamond, graphite, glassy carbon, amorphous carbon, carbon nanotubes, carbon nanohorns, graphene, and metal carbides.

[0094] Furthermore, when the electrolytic solution to be electrolyzed contains water in addition to carbon dioxide, it becomes possible to obtain various organic compounds by electrolytic reduction.

[0095] Examples of the organic compound include hydrocarbons, ethers, cyclic ethers, alcohols, and carbonyl compounds. More specifically, examples of the organic compound include one or more compounds selected from the group consisting of methane, methanol, ethane, ethylene, acetylene, ethanol, formic acid, formaldehyde, oxalic acid, acetic acid, propane, propylene, propanol, butane, butene, butanol, acetone, benzene, toluene, and xylene.

[0096] Furthermore, when the electrolytic solution to be electrolyzed further contains nitrogen, it is also possible to obtain amines and the like.

[0097] (2-2) Other embodiment B In the above embodiment, an example was given in which one electrolytic reduction device 70 was provided for the flow of the electrolyte.

[0098] Alternatively, a plurality of electrolytic reduction devices 70 may be arranged in parallel with respect to the flow of the electrolytic solution. This makes it possible to increase the number of locations where electrolytic reduction is performed, thereby making it possible to adjust the scale of treatment.

[0099] (2-3) Other embodiment C In the energy utilization system 1 according to the above embodiment, an example has been described in which the first refrigerant circulating through the heat pump 10 driven by renewable energy heats the heat medium circulating through the heat utilization cycle 30, and the heat medium circulating through the heat utilization cycle 30 heats the electrolyte in the electrolytic reduction device 70.

[0100] In contrast, the energy utilization system 1 is not limited to a system in which the electrolytic solution of the electrolytic reduction device 70 is heated, but may be a system in which the electrolytic solution of the electrolytic reduction device 70 is cooled, or a system in which the electrolytic solution of the electrolytic reduction device 70 can be switched between heating and cooling.

[0101] In this case, the first refrigerant circulating through the heat pump 10 driven by renewable energy may be one that cools the heat medium circulating through the heat utilization cycle 30, or may be configured to be able to switch between heating and cooling.

[0102] By suppressing the temperature rise of the electrolyte, it is possible to suppress the decrease in the solubility of the electrolyte in carbon dioxide to a small extent. In addition, if a side reaction occurs during electrolytic reduction, it is possible to suppress the reaction rate of the side reaction to a small extent.

[0103] Furthermore, in order to cool the electrolytic solution, a flow path through which a cooling medium such as water or air supplied from an external cooling source flows may be provided so that the cooling medium passes through the thermostatic bath 33x in the thermostatic container 70x.

[0104] (2-4) Other embodiment D The form of use of the energy utilization system 1 of the first embodiment is not particularly limited, and it can be used in, for example, a microgrid system.

[0105] A microgrid system is an energy system that integrates and operates distributed energy resources (DERs), such as distributed energy and energy storage facilities, and an energy network on a certain scale. For example, the microgrid system may be a system that is completely separated from the main power network operated by the power company and always operates independently, or may be a system that is connected to the main power network operated by the power company under normal circumstances and is disconnected from the network in an emergency such as a disaster and operates independently.

[0106] FIG. 4 shows an example of a network configuration of a microgrid system including the energy utilization system 1 of the first embodiment.

[0107] The microgrid system may include, for example, a renewable energy supply unit 91 such as a solar power plant, a wind power plant, a hydroelectric power plant, or the like, a renewable energy management device 180 that manages renewable energy, a heat pump 10, a heat engine 20, a heat utilization cycle 30, an exhaust heat supply unit 92, a carbon dioxide treatment device 40 including a carbon dioxide recovery device 50 and an electrolytic reduction device 70, an emission supply unit (not shown) such as a thermal power plant, a nuclear power plant, a plant, a hot spring, or the like, an emission management device 150 that manages the emission supply unit, consumer equipment (not shown) that consumes the electric power energy generated by the heat engine 20, a consumer terminal 160 that manages the consumer equipment, energy network equipment (not shown) that connects these facilities, an energy management controller 100 that appropriately controls the supply and consumption of energy, and a communication network 111 that communicatively connects the renewable energy management device 180, the consumer terminal 160, the energy management controller 100, and the like.

[0108] The renewable energy management device 180 has a processor 181 such as a CPU, a memory 182 such as a ROM, a RAM, and an electric energy amount grasping unit 183 that grasps the amount of electric power generated in the renewable energy supply unit 91, and is disposed in the renewable energy supply unit 91. The renewable energy management device 180 is connected to the energy management controller 100 via the communication network 111 so as to be able to communicate with each other.

[0109] The emission management device 150 has a processor 151 such as a CPU, a memory 152 such as a ROM or RAM, a thermal energy amount grasping unit 153, and an emission carbon dioxide amount grasping unit 154, and is disposed in an emission supply unit of a thermal power plant, a nuclear power plant, or the like. The emission management device 150 is communicatively connected to the energy management controller 100 via a communication network 111. The thermal energy amount grasping unit 153 grasps the amount of thermal energy emitted from the emission supply unit of the thermal power plant, the nuclear power plant, or the like. The emission carbon dioxide amount grasping unit 154 grasps the amount of carbon dioxide emitted from the emission supply unit of the thermal power plant, or the like.

[0110] The consumer equipment is equipment that consumes the remaining electric energy after the electric energy generated by the heat engine 20 is used in the electrolytic reduction device 70, or consumes the remaining thermal energy after the thermal energy obtained by the heat pump 10 is used in the electrolytic reduction device 70, or consumes both of these, and examples thereof include factories, office buildings, houses, power supply devices for electric vehicles, and plant factories. Of these, for example, the heat stored in the heat utilization cycle 30 is supplied to the factories, office buildings, houses, and plant factories in response to requests from these. The heat may be supplied to the consumer by, for example, transporting a heat storage material capable of storing heat to the location of the consumer equipment. In addition, the electric energy generated by the heat engine 20 is supplied to the factories, office buildings, houses, power supply devices for electric vehicles, and plant factories in response to requests from these. The electric energy may be supplied by transporting it to the location of the consumer equipment using electric wires, storage batteries, or the like. These heat storage materials, electric wires, and storage batteries are used as energy network equipment. In response to requests from users, the carbon-containing material obtained in the electrolytic reduction device 70 is supplied by transportation or the like.

[0111] The consumer terminal 160 has a processor 161 such as a CPU, a memory 162, an input unit 163, etc., and is disposed in consumer equipment. The consumer terminal 160 is communicatively connected to the energy management controller 100 via the communication network 111. The input unit 163 is configured with a touch panel, a keyboard, etc., and receives at least one of requests from a consumer who is the holder of the consumer terminal 160, including a request for thermal energy supply, a request for electric energy supply, and a request for carbon-containing material obtained by electrolytic reduction.

[0112] The energy management controller 100 has a processor 101 such as a CPU (Central Processing Unit) and a memory 102 such as a ROM or RAM. The energy management controller 100 is communicably connected to the heat pump 10, the heat engine 20, the heat utilization cycle 30, the exhaust heat supply unit 92, the carbon dioxide treatment device 40 including the carbon dioxide capture device 50 and the electrolytic reduction device 70, and the like. The energy management controller 100 controls the operation of the heat pump 10, the heat engine 20, the heat utilization cycle 30, the exhaust heat supply unit 92, the carbon dioxide treatment device 40 including the carbon dioxide capture device 50 and the electrolytic reduction device 70, and the like, based on various information received via a communication network 111.

[0113] The energy management controller 100 controls the heat pump 10 by controlling the rotation speed of the first compressor 12 in the heat pump 10 to convert the electric energy into stored heat energy based on the amount of electric energy grasped by the renewable energy supply unit 91 of the renewable energy management device 180. Although the amount of renewable energy obtained by the renewable energy management device 180 tends to be unstable compared to general electric energy provided by electric power companies, it is possible to convert the energy supplied as renewable energy into heat energy via the heat pump 10 and store it in the heat utilization cycle 30. The heat energy stored in the heat medium in the heat utilization cycle 30 can be used when electrolytically reducing the electrolyte in the electrolytic reduction device 70. Specifically, the heat energy stored in the heat medium in the heat utilization cycle 30 is used to heat the electrolyte in the electrolytic reduction device 70, and the electric energy obtained by converting the heat energy stored in the heat medium in the heat utilization cycle 30 by the heat engine 20 is used to apply a voltage to the electrolyte in the electrolytic reduction device 70. This makes it possible to cover the energy required for heating the electrolyte and applying a voltage in the electrolytic reduction device 70 with the energy stored in the heat utilization cycle 30, rather than with unstable renewable energy, and thus makes it possible to stably perform electrolytic reduction. More specifically, data such as a desired temperature of the electrolyte to be electrolytically reduced in the electrolytic reduction device 70 and a desired applied voltage are stored in advance in the memory 102 provided in the energy management controller 100, and the flow rate of the heat medium in the heat medium pump 32, the flow rate of the electrolyte in the electrolyte pump 42, the amount of cold supplied to the electrolyte cooling unit 94, and the like are controlled based on the data so that the temperature conditions and applied voltage conditions of the electrolyte are satisfied.

[0114] In addition, the energy management controller 100 adjusts the amount of thermal energy of exhaust heat supplied to the exhaust heat supply unit 92 by controlling the exhaust gas transportation means, etc., based on the amount of thermal energy discharged from an exhaust supply unit of a thermal power plant, a nuclear power plant, etc., which is grasped by the thermal energy amount grasping unit 153, and information on the control of the rotation speed of the first compressor 12.

[0115] Furthermore, the energy management controller 100 adjusts the amount of carbon dioxide supplied to the carbon dioxide supply line 81 by controlling carbon dioxide transportation means, etc., based on the amount of carbon dioxide emitted from an exhaust supply unit such as a thermal power plant, which is grasped by the emission carbon dioxide amount grasping unit 154.

[0116] In addition, when the amount of thermal energy grasped by the thermal energy amount grasping unit 153 is sufficient, the energy management controller 100 can improve the operating efficiency by heating the first refrigerant in the first intermediate heat exchanger 14 of the heat pump 10, or by heating the heat medium in the low-temperature tank 35 and the high-temperature tank 37 of the heat utilization cycle 30.

[0117] (Additional Note) Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure described in the claims. [Explanation of symbols]

[0118] 1 Energy Utilization System 10. Heat Pumps 12 First compressor 13 1st high temperature heat exchanger 15 Expansion valve 20 Heat Engine 23 2nd high temperature heat exchange section 24 Expander 30 Heat Utilization Cycle (Circulation Circuit) 32 Heat Transfer Pump 34 Low temperature heat exchanger 35 Low Temperature Tank 36 High temperature heat exchange section (temperature adjustment section) 37 High temperature tank (storage section) 40 Carbon dioxide treatment device 41 Electrolyte circuit 42 Electrolyte Pump 43 Electrolyte heat exchanger 50 Carbon dioxide capture equipment 70 Electrolytic reduction device 70x constant temperature container 71 Anode (first electrode) 71x Anode recovery channel (first gas flow path) 71a Anode catalyst layer 71b Anode gas diffusion layer 72 Cathode (second electrode) 72a Cathode catalyst layer 72b Cathode gas diffusion layer 72x Cathode recovery channel (second gas flow path) 73 Electrolyte flow path 79 Electrolyzer Casing (Casing) 81 Carbon Dioxide Supply Line 82 Air Outlet Line 83 First Recovery Route 84 2nd Recovery Route 91 Renewable Energy Supply Division 92 Exhaust heat supply section 93 Second refrigerant cooling section 94 Electrolyte cooling section 100 Energy Management Controller [Prior art documents] [Patent documents]

[0119] [Patent Document 1] JP 2016-89230 A [Patent Document 2] JP 2023-15104 A

Claims

1. An energy utilization system (1) comprising: a temperature adjustment unit (36) that adjusts the temperature of a heat medium by utilizing renewable energy or energy obtained from exhaust heat; a circulation circuit (30) through which the heat medium circulates; and an electrolytic reduction device (70) that electrolytically reduces an electrolyte solution having carbon dioxide dissolved therein, the electrolytic reduction device electrolytically reduces the electrolyte whose temperature has been adjusted by thermal contact with the heat medium; The electrolytic reduction device is A cylindrical casing (79) extending in a first direction; A first electrode (71) provided inside the casing and extending in the first direction; A cylindrical second electrode (72) that is located inside the casing and outside the first electrode when viewed in the first direction and extends in the first direction; an electrolyte flow path (73) for flowing the electrolyte in the first direction between the first electrode and the second electrode; having the first electrode is an anode; The second electrode is a cathode. Energy utilization system.

2. The anode has a cylindrical shape extending in the first direction, The electrolytic reduction device has a first gas flow path (71x) that is provided inside the anode when viewed in the first direction and that allows a gas generated by an oxidation reaction of the electrolytic solution to pass through. The energy utilization system according to claim 1 .

3. The anode has a cylindrical anode catalyst layer (71a) extending in the first direction, and a cylindrical anode gas diffusion layer (71b) extending in the first direction, the cylindrical anode gas diffusion layer (71b) being provided inside the anode catalyst layer and outside the first gas flow path when viewed in the first direction. The energy utilization system according to claim 2 .

4. The electrolytic reduction device has a second gas flow path (72x) that is provided outside the cathode and inside the casing when viewed in the first direction, and that allows a gas generated by a reduction reaction of the electrolytic solution to pass through. The energy utilization system according to claim 1 or 2.

5. The cathode has a cylindrical cathode catalyst layer (72a) extending in the first direction, and a cylindrical cathode gas diffusion layer (72b) extending in the first direction, the cylindrical cathode gas diffusion layer (72b) being provided on the outside of the cathode catalyst layer and inside the second gas flow path when viewed in the first direction. The energy utilization system according to claim 4.

6. The system further includes a heat pump (10) that is driven by electricity generated by the renewable energy and through which a first refrigerant circulates, The temperature adjustment unit adjusts the temperature of the heat medium by the heat of the first refrigerant whose temperature has been adjusted by the heat pump. The energy utilization system according to claim 1 or 2.

7. The circulation circuit has a storage section (37) that stores the heat of the heat medium as stored energy. The energy utilization system according to claim 1 or 2.

8. An energy utilization system (1) having a temperature adjustment unit (36) that adjusts the temperature of a heat medium by utilizing renewable energy or energy obtained from exhaust heat, a circulation circuit (30) through which the heat medium circulates, and an electrolytic reduction device (70) that electrolytically reduces an electrolyte having carbon dioxide dissolved therein, the electrolytic reduction device electrolytically reduces the electrolyte whose temperature has been adjusted by thermal contact with the heat medium; The electrolytic reduction device is A cylindrical casing (79) extending in a first direction; A first electrode (71) provided inside the casing and extending in the first direction; A cylindrical second electrode (72) that is located inside the casing and outside the first electrode when viewed in the first direction and extends in the first direction; an electrolyte flow path (73) for flowing the electrolyte in the first direction between the first electrode and the second electrode; having A heat engine (20) is provided which generates electricity by utilizing the heat of the heat medium, The electrolytic reduction device applies a voltage to the electrolyte by utilizing the electric power generated by the heat engine. Energy utilization system.

9. A step of adjusting the temperature of a heat medium circulating in a circulation circuit (30) by utilizing renewable energy or energy obtained from exhaust heat; adjusting the temperature of the electrolytic solution having carbon dioxide dissolved therein by thermally contacting the electrolytic solution with the heat transfer medium; a step of electrolytically reducing the temperature-adjusted electrolyte; Equipped with In the electrolytic reduction step, the electrolytic solution flows in the first direction between a first electrode (71) extending in a first direction and a cylindrical second electrode (72) extending in the first direction so as to surround the first electrode when viewed in the first direction; the first electrode is an anode; The second electrode is a cathode. A method for producing a carbon-containing material.

10. The temperature of the heat medium is adjusted by the heat of a first refrigerant using a heat pump (10) in which the first refrigerant circulates; The heat pump is driven by using electricity generated by the renewable energy. The method for producing a carbon-containing material according to claim 9.

11. A step of adjusting the temperature of a heat medium circulating in a circulation circuit (30) by utilizing energy obtained from renewable energy or exhaust heat; adjusting the temperature of the electrolytic solution having carbon dioxide dissolved therein by thermally contacting the electrolytic solution with the heat transfer medium; a step of electrolytically reducing the temperature-adjusted electrolyte; Equipped with In the electrolytic reduction step, the electrolytic solution flows in the first direction between a first electrode (71) extending in a first direction and a cylindrical second electrode (72) extending in the first direction so as to surround the first electrode when viewed in the first direction; The method further comprises the step of generating electricity in a heat engine (20) by utilizing the heat of the heat medium, In the electrolytic reduction step, a voltage is applied to the electrolyte using the electric power generated by the heat engine. A method for producing a carbon-containing material.

12. The circulation circuit has a storage section (37) that stores the heat of the heat medium as stored energy. The method for producing a carbon-containing material according to claim 11.

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