Method and apparatus for recovering solid carbon and combustible gas using renewable energy

Abstract

To provide a method for efficiently separating carbon dioxide gas in the air, combustion exhaust gas and biogas using renewable energy and recovering it as solid carbon and combustible gas suitable for immobilization and commercial and industrial use, and a system for generating and recovering solid carbon and combustible gas utilizing renewable energy by applying the method.SOLUTION: A gas suction pump installed in a carbon dioxide gas permeation side channel of a carbon dioxide separation membrane is directly rotationally driven by the rotary driving force generated by the energy of geothermal fluid or flowing water to separate, suck and recover carbon dioxide gas from air, biogas or combustion exhaust gas, and the separated and recovered carbon dioxide gas is subjected to electrolytic reduction or steam reforming using the electric power or cold heat obtained from the energy of geothermal fluid or flowing water to generate and recover solid carbon or combustible gas.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for recovering solid carbon or carbon monoxide gas from carbon dioxide contained in the atmosphere, biogas, and combustion exhaust gas by utilizing renewable energy such as geothermal and hydroelectric power that can be used stably regardless of the weather or time of day, a method for recovering biofuel gas such as biomethane or biohydrogen while recovering solid carbon from biogas, and an apparatus that applies these methods. [Background technology]

[0002] To prevent global warming, efforts are being made to reduce emissions of carbon dioxide, a major cause of global warming, and to separate, capture, and fix carbon dioxide accumulated in the atmosphere by injecting it underground. In particular, technologies that separate, capture, and fix carbon dioxide in exhaust gases generated when biomass resources are burned, and carbon dioxide in the atmosphere, are expected to be implemented in society and become more widespread as negative emission technologies that contribute to the active reduction of carbon dioxide accumulated in the atmosphere.

[0003] On the other hand, carbon dioxide gas is highly chemically stable and difficult to decompose, so when it is immobilized deep underground, it must be compressed and liquefied, transported to an underground storage site, and then injected, consuming a great deal of energy, to be stored deep underground. This energy consumption increases costs and poses the problem of reducing the net amount of carbon dioxide immobilized.

[0004] Furthermore, there are limitations on the number of locations where carbon dioxide can be stored underground stably over the long term, and the amount that can be injected and fixed at each storage location. Therefore, once the storage amount reaches its limit, even if carbon dioxide can be transported, it will become impossible to fix it by underground injection.

[0005] To address these issues, technologies have been developed that are expected to be put into practical use, including electrolytic reduction of carbon dioxide using electricity generated from renewable energy sources to recover solid carbon and carbon monoxide gas, and the production of carbon-neutral fuel using the recovered carbon monoxide and hydrogen derived from renewable energy, as well as the use of recovered solid carbon as a raw material in the production of carbon-fixing materials such as carbon fiber and silicon carbide.

[0006] Among these, as resource recovery technologies for separating and recovering carbon dioxide and electrolyzing it using renewable energy, there have been disclosed a technology in which water is supplied to the anode side of a solid polymer carbon dioxide electrolysis cell, carbon dioxide gas is supplied to the cathode side, and electrolysis is carried out at room temperature and normal pressure to convert the carbon dioxide into carbon monoxide gas (Non-Patent Document 1), and a technology in which solid carbon dioxide and carbon monoxide gas are recovered from carbon dioxide gas by using a zirconium oxide solid electrolyte as the anode electrode and a stainless steel tube into which carbon dioxide is blown into a calcium chloride molten salt as the cathode electrode, and passing electricity through the electrodes while blowing in the carbon dioxide gas, thereby electrolyzing the carbon dioxide gas in the molten salt (Non-Patent Document 2).

[0007] Furthermore, in order to address the increasing costs associated with the energy consumption involved in the separation, capture, and fixation of carbon dioxide, and to improve the net carbon dioxide reduction effect due to carbon dioxide emissions, a method has been disclosed in which carbon dioxide gas contained in the atmosphere, biogas, or combustion exhaust gas is separated and captured using renewable energy sources that do not involve carbon dioxide emissions, such as geothermal steam, hot spring heat, and flowing water from rivers and tidal currents, and then recovered as liquefied carbon dioxide or dry ice suitable for transportation and commercial and industrial use (Patent Document 1). [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] TIFF0007764678000001.tif21125 [Non-patent document 2] TIFF0007764678000002.tif21124 [Patent documents]

[0009] [Patent Document 1] Patent application No. 2021-132079 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0010] As described above, the conventional technology disclosed in Non-Patent Document 1 makes it possible to produce and recover carbon monoxide gas from carbon dioxide gas using renewable energy electricity, and the conventional technology disclosed in Non-Patent Document 2 makes it possible to recover solid carbon and carbon monoxide gas from carbon dioxide gas. Furthermore, the conventional technology disclosed in Patent Document 1 makes it possible to efficiently separate and recover carbon dioxide from air, biogas, or combustion exhaust gas using renewable energy, and recover it as liquefied carbon dioxide or dry ice, which are easy to transport and use, but these technologies have the following three problems.

[0011] First, conventional technologies do not provide a consistent process that covers everything from the separation and recovery of carbon dioxide gas to the production and recovery of solid carbon, biomethane, hydrogen, and combustible gases such as carbon monoxide. In particular, they do not provide a method that enables this consistent process to be run stably and continuously, day or night, regardless of the weather, using renewable energy sources such as geothermal or hydroelectric power that do not emit carbon dioxide, thereby enabling the continuous production and recovery of solid carbon and combustible gases at all times.

[0012] Furthermore, when recovering carbon dioxide gas contained in the atmosphere, combustion exhaust gas, and biogas using a carbon dioxide separation membrane, depending on the material and properties of the separation membrane, it is desirable to install a vacuum pump or suction blower in the recovery flow path for the carbon dioxide gas that has permeated the separation membrane, and to maintain a negative pressure on the carbon dioxide gas permeation side of the separation membrane or to increase the suction force.However, conventional technology is configured to compress and pressurize the gas on the upstream side of the separation membrane before supplying it to the separation membrane, which poses the problem of making it difficult to apply a separation membrane that is suitable for an operation method such as the one described above that maintains a negative pressure on the carbon dioxide gas side.

[0013] Furthermore, when a vacuum pump or suction blower is installed in the carbon dioxide gas recovery flow path to perform separation and recovery, the vacuum pump or suction blower, which consumes a large amount of energy, is often driven by an electric motor. However, if the power used to drive this motor is not renewable energy, carbon dioxide gas is generated during the separation and recovery of carbon dioxide, reducing the net carbon dioxide reduction effect. Furthermore, even when the power used to drive the motor is provided by renewable energy, if the rotational driving force obtained from geothermal or hydroelectric power is not used directly to drive the pump or blower, losses occur due to the power conversion and transmission of the rotational driving force, resulting in a decrease in energy utilization efficiency. [Means for solving the problem]

[0014] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide an integrated process that can continuously produce solid carbon and combustible gas regardless of day or night or weather, by efficiently separating and capturing carbon dioxide gas in the atmosphere, combustion exhaust gas, or biogas using rotational driving force, electricity, and cold and hot energy obtained from renewable energy sources such as geothermal and hydroelectric power, which allow stable energy use regardless of day or night or weather, and further generating and capturing solid carbon and combustible gas from the captured carbon dioxide gas, and providing a renewable energy-based solid carbon capture system and a combustible gas production and capture system that apply this technology.

[0015] In order to solve the above problem, the invention described in claim 1 is: The rotary driving force generated by the energy of either geothermal fluid or water flow directly drives a vacuum pump or suction blower installed in the flow path of carbon dioxide gas that has permeated the carbon dioxide gas separation membrane, thereby separating and suction recovering carbon dioxide gas from either air, biogas, or combustion exhaust gas.

[0016] The invention described in claim 2 is The carbon dioxide gas separation and recovery method described in claim 1 is characterized in that the temperature of the supply gas upstream of the carbon dioxide separation membrane is controlled to achieve the conditions most suitable for separation and recovery by using one or more of the heat from an electric heater using geothermal fluid or hydroelectric power, cold energy obtained from an absorption or adsorption chiller driven by geothermal fluid, or cold energy obtained from water used for hydroelectric power generation.

[0017] The invention described in claim 3 is In the carbon dioxide gas separation and recovery method described in claim 1, the humidity of the gas supplied to the carbon dioxide separation membrane is controlled so that the humidity of the supply gas upstream of the carbon dioxide separation membrane is optimal for separation and recovery by humidifying the supply gas with water vapor obtained by evaporating water using the heat of an electric heater using geothermal fluid or hydroelectric power, or by cooling the supply gas with cold energy obtained from an absorption or adsorption chiller driven by geothermal fluid or cold energy obtained from water used in hydroelectric power generation, thereby condensing the water and dehumidifying it.

[0018] The invention described in claim 4 is The system uses high-temperature, high-pressure steam obtained from geothermal fluid as the working fluid, and separates and sucks carbon dioxide gas from either air, biogas, or combustion exhaust gas using an ejector equipped with a carbon dioxide separation membrane at the gas intake port. After recovering a mixture of carbon dioxide and water vapor, the mixture is cooled to condense and separate the water, thereby separating and recovering the carbon dioxide gas.

[0019] The invention described in claim 5 is The condensation of water from the air-fuel mixture as described in claim 4 is characterized in that a condenser that circulates and supplies cooling water is used, and the cooling water supplied to the condenser is cooled by cold energy obtained from an absorption or adsorption chiller driven by steam obtained from geothermal fluid or condensed and recovered hot water.

[0020] The invention described in claim 6 is The method is characterized in that a vessel containing high-temperature molten salt heated and maintained using renewable energy electricity obtained from geothermal power generation or hydroelectric power generation is equipped with electrodes for supplying the electricity, and while carbon dioxide gas separated and recovered by the method of claim 1 or claim 4 is supplied into the high-temperature molten salt, the renewable energy electricity is supplied to the electrodes, thereby electrolytically reducing the carbon dioxide gas to solid carbon and carbon monoxide, and recovering solid carbon and carbon monoxide gas from the separated and recovered carbon dioxide gas.

[0021] The invention described in claim 7 is The method is characterized in that renewable energy electricity obtained from geothermal or hydroelectric power generation, water obtained by purifying hot water after geothermal power generation or water obtained by purifying flowing water before or after hydroelectric power generation, and carbon dioxide gas separated and recovered by the method of claim 1 or claim 4 are supplied to an electrolytic cell, where the carbon dioxide gas is electrolytically reduced to carbon monoxide gas, and the carbon monoxide gas is recovered from the separated and recovered carbon dioxide gas.

[0022] The invention described in claim 8 is The carbon monoxide gas according to claim 6 or 7 is supplied to a gas reactor that is heated by renewable energy electricity obtained from geothermal or hydroelectric power generation and is equipped with a carbon deposition plate containing a catalyst that promotes carbon deposition, and solid carbon is deposited from the carbon monoxide gas, thereby recovering solid carbon from the separated and recovered carbon dioxide gas.

[0023] The invention described in claim 9 is The carbon deposition plate described in claim 8 is equipped with an ultrasonic vibrator driven by renewable energy electricity obtained from geothermal power generation or hydroelectric power generation, and carbon is deposited on the carbon deposition plate while vibrating at high frequency, thereby continuously depositing and recovering carbon while peeling off and removing the carbon deposited on the carbon deposition plate.

[0024] The invention described in claim 10 is The molten salt electrolysis device according to claim 6 or the gas reactor according to claim 8 is characterized in that it is equipped with a mechanism for continuously discharging precipitated solid carbon by a solid carbon discharge mechanism driven by renewable energy electricity obtained from geothermal power generation or hydroelectric power generation, thereby preventing blockages due to carbon deposition in the molten salt electrolysis device and the gas reactor and continuously recovering solid carbon while maintaining a stable reaction.

[0025] The invention described in claim 11 is The method is characterized in that biomethane obtained when carbon dioxide is separated and recovered from biogas by the method of claim 1 or 4 is mixed with geothermal steam or steam obtained by evaporating water by heating with an electric heater using electricity from geothermal or hydroelectric power generation, and then supplied to a steam reforming catalyst heated by an electric heater using electricity from geothermal or hydroelectric power generation to perform steam reforming. Carbon monoxide gas is then subjected to a transformation reaction to generate a mixture of hydrogen, carbon dioxide, and steam. The mixture is then cooled and dehumidified and supplied to a carbon dioxide separation membrane to separate and recover the carbon dioxide, thereby recovering hydrogen gas originating from the biogas.

[0026] The invention described in claim 12 is The present invention is characterized in that it is configured as a renewable energy-based solid carbon recovery system to which one or more of the renewable energy-based carbon dioxide separation and recovery methods set forth in claims 1 to 5 and one or more of the solid carbon recovery methods set forth in claims 6 to 10 are applied.

[0027] The invention described in claim 13 is The present invention is characterized in that a renewable energy-based carbon monoxide gas recovery system is configured to recover carbon monoxide gas from separated and recovered carbon dioxide gas by using one or more of the renewable energy-based carbon dioxide separation and recovery methods described in claims 1 to 5 and the method described in claim 6 or 7.

[0028] The invention described in claim 14 is The present invention is characterized in that a renewable energy-based hydrogen gas recovery system is configured, which separates and recovers carbon dioxide from biogas and then recovers hydrogen gas, by applying one or more of the renewable energy-based carbon dioxide separation and recovery methods described in claims 1 to 5 and the hydrogen gas recovery method described in claim 11.

[0029] [Effects of the Invention]

[0030] According to the present invention, rotational driving force, electricity, and heating and cooling energy obtained from renewable energy sources such as geothermal steam and hydraulic power are used directly to separate and capture carbon dioxide contained in the atmosphere, combustion exhaust gas, or biogas, and the carbon dioxide is recovered as solid carbon, carbon monoxide gas, methane gas, or hydrogen gas. This reduces the consumption of fossil fuels involved in the separation and capture of carbon dioxide, increases the net carbon dioxide capture effect, and makes it possible to recover and utilize not only solid carbon, which is easy to transport, immobilize, and use as a raw material, but also carbon monoxide gas, methane gas, and hydrogen gas, which are industrial raw materials.

[0031] Furthermore, even in places where renewable energy resources are abundant but where it is difficult to effectively utilize renewable energy due to constraints such as insufficient capacity in the power transmission and distribution network and the efficiency of heat storage and transportation, it will be possible to continuously separate and capture carbon dioxide from the atmosphere or biomass sources, and fix or convert it into resources, without being affected by power grid outages. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is a schematic diagram showing a system for recovering solid carbon from atmospheric carbon dioxide by utilizing geothermal energy, which is a first embodiment of the present invention. [Figure 2] FIG. 1 is a schematic diagram showing a system that utilizes geothermal energy and uses an ejector to recover solid carbon from carbon dioxide in the atmosphere, according to a second embodiment of the present invention. [Figure 3]FIG. 10 is a schematic diagram showing a system for recovering compressed carbon monoxide gas from atmospheric carbon dioxide by utilizing hydraulic energy, which is a third embodiment of the present invention. [Figure 4] FIG. 10 is a schematic diagram showing a system for recovering solid carbon and compressed hydrogen gas from biogas by utilizing geothermal energy, which is a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0033] The best mode for carrying out the present invention will be described below with reference to the drawings. The scope of the present invention is defined by the claims and is not limited to the present embodiment.

[0034] (First embodiment)

[0035] First, a system for recovering solid carbon from atmospheric carbon dioxide by utilizing geothermal energy according to a first embodiment of the present invention will be described with reference to FIG.

[0036] As shown in Figure 1, this system includes a steam turbine 3 driven by the geothermal steam discharged from the steam turbine separator, a steam turbine shaft connected to the steam turbine via a transmission 4, and a vacuum pump 7 for creating a negative pressure on the carbon dioxide gas permeation side of a separation membrane module 6 that separates and captures carbon dioxide from air drawn in through an intake port 5 with an intake filter. The vacuum pump 7 then sucks and captures the separated and captured carbon dioxide gas. The system uses the rotational force of the steam turbine, which is obtained directly from geothermal energy, to efficiently separate and capture carbon dioxide gas from the atmosphere via the separation membrane.

[0037] Furthermore, this system is composed of a molten salt-based carbon dioxide gas electrolysis device 10, which ejects the separated and recovered carbon dioxide gas as fine bubbles into molten salt for electrolytic reduction, and recovers solid carbon 8 and carbon monoxide gas from a carbon monoxide gas recovery pipe 9, and a heated catalyst-based solid carbon deposition and recovery device 11, which recovers the carbon monoxide gas recovered from the above device as solid carbon by depositing carbon using a heated catalyst.

[0038] In the molten salt carbon dioxide electrolysis device 10, calcium chloride is melted and maintained by heating with an electric heater 13 supplied with renewable energy electricity obtained from a generator 12 connected to a geothermal steam turbine in a container covered with thermal insulation material, and a solid electrolyte anode 14 made of zirconium oxide or the like and a carbon dioxide gas reduction cathode 15 are inserted therein, which is energized as a cathode while ejecting separated and recovered carbon dioxide gas as fine bubbles. As renewable energy electricity is supplied while carbon dioxide gas is ejected into the molten salt as fine bubbles, electrolysis occurs in the molten salt, and solid carbon precipitates and floats and accumulates on the surface of the molten salt. At the same time, some of the carbon dioxide gas turns into carbon monoxide gas, which is recovered from the carbon monoxide gas recovery pipe 9 and supplied to the heated catalyst-utilizing solid carbon deposition and recovery device 11.

[0039] Furthermore, the heated catalyst-utilizing solid carbon deposition and recovery device 11 contains catalytic components, such as nickel and iron, used for carbon deposition from carbon monoxide gas. The inner wall of the device is made up of a carbon deposition heating plate 16 equipped with an electric heater, and an ultrasonic vibrator 17 is attached to the outer wall of the device. The heating power of the electric heater and the driving power of the ultrasonic vibrator are provided by renewable energy electricity obtained from the geothermal generator 12. As a result, the carbon deposition heating plate is heated to a high temperature of 300 to 600°C, which is optimal for carbon deposition from carbon monoxide gas, and solid carbon is continuously deposited on the surface of the carbon deposition heating plate. At the same time, the carbon deposition plate is vibrated by the ultrasonic vibrator, causing the deposited solid carbon to peel off and accumulate at the bottom of the recovery device. This accumulated solid carbon is then rotated by a motor-driven solid carbon discharge screw plate 18, which discharges the solid carbon out of the device, making it possible to continuously deposit and recover solid carbon from carbon monoxide gas as well.

[0040] Furthermore, in this system, in order to maximize the performance of the separation and recovery membrane in separating and recovering carbon dioxide gas, an intake gas temperature and humidity adjustment device 19 is installed, and a mechanism is provided to optimize the temperature and humidity of the supply gas when separating and recovering carbon dioxide gas.

[0041] In other words, when the performance of the carbon dioxide separation membrane is improved when the gas is humidified at high temperatures, the supply gas can be humidified by adjusting the amount of high-temperature geothermal steam supplied to the geothermal steam turbine 3 using the flow control valve 20, and heated by adjusting the amount of water supplied to the heater 22 using the flow control valve 21.When low-temperature dehumidification is preferred, the supply gas can also be cooled and dehumidified by supplying cooling water to a gas cooling dehumidifier 23, which cools and dehumidifies the supply gas, using the cooling water adjustment valve 24 to adjust the amount of water, and condensing the excess moisture contained in the supply gas and discharging it as it is drained.

[0042] The cooling water supplied here is cooled using renewable energy cold energy obtained by an absorption chiller 25 driven by high-temperature water obtained by steam-liquid separation in the geothermal steam steam-liquid separator 2. In adjusting the temperature and humidity of the supply gas, the operating status of the entire system, including the adjustment of the temperature and humidity of the supply gas, is monitored based on temperature and humidity data measured by a supply gas temperature and humidity measuring device 26 installed upstream of the carbon dioxide separation membrane module 6, and the flow control valves 20, 21 and 24 are controlled by an operation control device 27 which issues control commands and controls the temperature and humidity of the supply gas, optimizing the temperature and humidity of the supply gas.

[0043] In addition, the supply gas blower 28 for sending the supply gas to the carbon dioxide gas separation membrane module 6, the cooling tower 29 which is an accessory to the absorption chiller for obtaining cooling water cooling heat, and the cooling water circulation pump 30, all of the electric equipment such as pumps and valves and their associated devices such as control devices and sensors that make up this system are powered by renewable energy electricity obtained from the geothermal steam turbine generator 12. As a result, there is no carbon dioxide emission associated with energy consumption when operating this system, which reduces energy procurement costs and maximizes the net carbon dioxide reduction effect.

[0044] This configuration makes it possible to utilize the rotational driving force, electricity, and cold and hot heat obtained from geothermal energy, which can be used stably day or night and in any weather, to constantly and stably separate and capture carbon dioxide from the atmosphere, and to recover solid carbon from the captured carbon dioxide gas, which can be easily transported, immobilized, and used as a raw material. (Second embodiment)

[0045] Next, a system for recovering solid carbon from atmospheric carbon dioxide by utilizing geothermal energy and an ejector according to a second embodiment of the present invention will be described with reference to FIG.

[0046] As shown in Figure 2, the system of the second embodiment has the same configuration in which carbon dioxide gas is separated and recovered using high-temperature hot water obtained after separation of geothermal steam and brackish water, and solid carbon is further recovered from the separated and recovered carbon dioxide gas. However, the system differs in that the mechanism for separating and recovering carbon dioxide uses the energy of geothermal steam that is emitted from the ground at high pressure to draw carbon dioxide gas from the atmosphere through a carbon dioxide separation membrane, using an ejector 31 equipped with a carbon dioxide gas separation membrane to draw carbon dioxide gas from the air using the energy of the geothermal steam emission, and then generating electricity by driving a steam turbine 3 with a mixture of geothermal steam and carbon dioxide gas, and then adjusting the supply of cooling water obtained by driving an absorption chiller using a cooling water regulating valve 24 to condense and remove the water vapor, thereby separating and recovering the carbon dioxide gas. (Third embodiment)

[0047] Next, a system for recovering compressed carbon monoxide gas from carbon dioxide in the atmosphere by utilizing hydraulic energy according to a third embodiment of the present invention will be described with reference to FIG.

[0048] As shown in Figure 3, the system of the third embodiment differs in that the vacuum pump 7 and carbon monoxide gas compressor 33 are driven via a transmission 4 by the rotational driving force of a water turbine device 32, which uses the hydropower of flowing river water as a renewable energy source, and the power obtained from a hydroelectric power generation system 34 drives a carbon dioxide electrolysis device 35, which electrolytically reduces carbon dioxide gas recovered via a solid polymer membrane to carbon monoxide gas, and the recovered carbon dioxide gas is electrolyzed to carbon monoxide gas, compressed, and filled into a carbon monoxide cylinder 36.

[0049] Another difference is that the water vapor used to humidify the supply gas is obtained by purifying river water pumped up from the river by operating a river water pump 37 and then evaporating it in an electrothermal evaporator 38, while the water from the pump 37 is used directly as cooling water for cooling the supply gas, and the pure water supplied to the carbon dioxide electrolysis device 35 is also purified by passing the water pumped up by the pump through an ion exchange resin membrane or the like before being supplied as pure water.

[0050] With this configuration, it is possible to separate and capture carbon dioxide from the atmosphere using hydraulic energy, and then perform electrolytic reduction of the separated and captured carbon dioxide using the electricity obtained from hydroelectric power generation and the water used in hydroelectric power generation, converting it into carbon monoxide gas and recovering it as a compressed gas. (Fourth embodiment)

[0051] Next, a system for recovering solid carbon and compressed hydrogen gas from biogas by utilizing geothermal energy according to a fourth embodiment of the present invention will be described with reference to FIG.

[0052] As shown in Figure 4, the basic configuration of the system of the fourth embodiment is similar to that of the first embodiment, but differs in that the supply gas used to separate and capture carbon dioxide is desulfurized biogas composed of 20 to 40 vol% carbon dioxide and biomethane, which is produced in a biomass methane fermentation tank 39 and passed through a desulfurization purification device 40. By changing the supply gas for separating and capturing carbon dioxide from air to biogas in this way, it becomes possible to efficiently separate and capture carbon dioxide from biogas that originates from atmospheric carbon dioxide.

[0053] Another difference with this system is that the biomethane produced after carbon dioxide gas has been separated and recovered from biogas is steam reformed using renewable energy electricity obtained from a geothermal steam turbine generator 12 and steam obtained from pure water obtained by purifying the hot water used to drive the absorption chiller, and then separated and recovered as compressed hydrogen gas.

[0054] Specifically, biomethane obtained when carbon dioxide gas is separated from biogas is mixed with steam obtained by vaporizing pure water obtained by pumping it up using a hot water pump 41 and passing it through a pure water production device 42 equipped with an ion exchange resin or the like using an electric heater vaporizer 43. The biomethane is then reformed using a steam reformer 47 which incorporates a steam reforming catalyst 44 and a carbon monoxide shift reaction catalyst 45 and is heated by an electric heater 46 supplied with some of the power generated by the geothermal steam turbine generator 12, resulting in a mixture of hydrogen, carbon dioxide, and steam.

[0055] Furthermore, in order to separate and recover hydrogen gas from the gas mixture, the gas mixture is dehumidified and cooled using cold energy obtained using an absorption refrigerator, and the gas mixture is dehumidified and cooled using a gas mixture dehumidifying and cooling device 48 to a temperature and humidity level that will optimize the separation performance of the carbon dioxide separation membrane.The gas mixture is then passed through the carbon dioxide separation membrane to separate and recover carbon dioxide gas, and the recovered carbon dioxide gas is mixed with carbon dioxide gas separated and recovered from the biogas and supplied to a carbon dioxide gas molten salt electrolysis device 10 to recover solid carbon.On the other hand, the separated and recovered hydrogen gas is compressed by a hydrogen gas compressor 49 that compresses gas using the rotational driving force of a geothermal steam turbine, and is compressed and filled into a hydrogen gas filling cylinder 50, allowing it to be separated and recovered in a form that is easy to transport and use.

[0056] As described above, renewable energy sources such as geothermal and hydroelectric power, which can be obtained stably day or night regardless of the weather, can be used to separate and capture carbon dioxide from the atmosphere, biogas, and combustion exhaust gas. The captured carbon dioxide gas can then be converted into solid carbon or carbon monoxide using renewable energy. This makes it possible to transport and immobilize carbon, as well as to recover it as solid carbon that can be easily used as a carbon-based raw material. It also makes it possible to produce and supply carbon monoxide gas, biomethane gas, and hydrogen gas derived from biomethane gas, which are highly useful as chemical raw materials. [Industrial Applicability]

[0057] The present invention is not limited to the above-described embodiments. For example, the embodiments of Figures 1, 2, and 4 may be configured to use not only high-temperature geothermal steam but also high-temperature hot spring heat to drive a binary turbine and electricity from a binary generator, and the supply gas may be cooled and dehumidified by an adsorption chiller driven by the hot spring heat after binary power generation. Furthermore, the use of hydropower in the embodiment of Figure 3 is not limited to rivers with a large head and a stable flow rate, but can also be applied to straits where stable tidal currents are available.

[0058] Furthermore, although the carbon dioxide separation membrane module illustrated in the present invention is a single layer, if a sufficient concentration of carbon dioxide gas cannot be obtained using only this separation membrane module, it is possible to configure a multi-stage carbon dioxide separation membrane module, such as by adding a second layer of carbon dioxide separation membrane module to the carbon dioxide gas recovery flow path on the permeate gas side of the carbon dioxide separation membrane module to increase the concentration of the recovered carbon dioxide gas, and to separate and recover high-concentration carbon dioxide gas.

[0059] As such, the above-described embodiments are merely illustrative, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included within the technical scope of the present invention. [Explanation of symbols]

[0060] 1...geothermal fluid 2...Brackish water separator 3. Steam turbine 4. Transmission 5····Air intake with intake filter 6. Carbon dioxide gas separation membrane 7. Vacuum pump for gas suction 8. Solid carbon 9 Carbon monoxide gas recovery pipe 10. Molten salt-based carbon dioxide electrolysis device 11. Solid carbon deposition recovery device 12. Geothermal steam turbine generator 13 Electric heater 14. Carbon dioxide gas reduction anode electrode 15. Carbon dioxide gas reduction cathode electrode 16 Carbon deposition heating plate 17. Ultrasonic vibrator 18. Solid carbon discharge screw plate 19. Intake gas temperature and humidity control device 20. Steam volume control valve for intake air humidification 21. Steam volume control valve for intake air heating 23. Intake gas cooling dehumidifier 24. Cooling water metering valve for intake gas cooling and dehumidification 25 Absorption chiller 26. Supply gas temperature and humidity measuring instrument 27. Operation control device 28. Supply gas blower 29...cooling tower 30 Cooling water circulation pump 31. Carbon dioxide gas separation membrane-equipped ejector 32...Waterwheel device 33 Carbon monoxide gas compressor 34 Hydroelectric Power Generation System 35 Carbon dioxide electrolytic reduction device 36 Carbon monoxide gas cylinder 37 River water pump 38 Electrically heated evaporator 39. Methane fermentation tank 40 Biogas desulfurization and purification equipment 41. Hot water pump 42...Pure water production equipment 43 Electric heater vaporizer 44...Steam reforming catalyst 45...Shift reaction catalyst 46 Electric heater 47 Steam reformer 48. Air-fuel mixture dehumidifying and cooling device 49 Hydrogen gas compressor 50 Hydrogen gas cylinder

Claims

1. A carbon dioxide gas separation and recovery method for separating and recovering carbon dioxide, comprising: Air, biogas, or combustion exhaust gas is fed to a carbon dioxide gas separation membrane, A vacuum pump or a suction blower provided in the flow path of the carbon dioxide gas that has permeated the carbon dioxide gas separation membrane is directly driven by a rotational driving force generated by the energy of either geothermal fluid or water flow, thereby separating and suction recovering carbon dioxide gas from either air, biogas, or combustion exhaust gas. A method for separating and recovering carbon dioxide gas using renewable energy, characterized by the above.

2. A method for separating and recovering carbon dioxide gas as described in claim 1, characterized in that the temperature of the supply gas upstream of the carbon dioxide separation membrane is controlled to be under the conditions most suitable for separation and recovery by using one or more of the heat from an electric heater using geothermal fluid or hydroelectric power, cold energy obtained from an absorption or adsorption chiller driven by geothermal fluid, or cold energy obtained from water used for hydroelectric power generation.

3. A method for separating and recovering carbon dioxide gas as described in claim 1, characterized in that the humidity of the gas supplied to the carbon dioxide separation membrane is controlled by humidifying the supply gas with water vapor obtained by evaporating water using the heat of an electric heater using geothermal fluid or hydroelectric power, or by cooling the supply gas with cold heat obtained from an absorption or adsorption refrigerator driven by geothermal fluid or cold heat obtained from water used in hydroelectric power generation, so that the humidity of the supply gas upstream of the carbon dioxide separation membrane is under the most suitable conditions for separation and recovery by the carbon dioxide membrane, thereby condensing and dehumidifying the water.

4. A renewable energy-based method for separating and recovering solid carbon and carbon monoxide gas, comprising: providing an electrode for supplying said power inside a vessel containing high-temperature molten salt that has been heated and maintained using renewable energy electricity obtained from geothermal power generation or hydroelectric power generation; and supplying the renewable energy electricity to the electrode while supplying carbon dioxide gas separated and recovered by the method of claim 1 into the high-temperature molten salt, thereby electrolytically reducing the carbon dioxide gas to solid carbon and carbon monoxide, and recovering solid carbon and carbon monoxide gas from the separated and recovered carbon dioxide gas.

5. A method for recovering carbon monoxide gas using renewable energy, characterized by supplying renewable energy electricity obtained from geothermal power generation or hydroelectric power generation, water obtained by purifying hot water after geothermal power generation or water obtained by purifying flowing water before or after hydroelectric power generation, and carbon dioxide gas separated and recovered by the method of claim 1 to an electrolytic cell, whereby the carbon dioxide gas is electrolytically reduced to carbon monoxide gas and the carbon monoxide gas is recovered from the separated and recovered carbon dioxide gas.

6. A method for recovering solid carbon using renewable energy, comprising: supplying the carbon monoxide gas according to claim 4 or 5 to a gas reactor that is heated by renewable energy electricity obtained from geothermal or hydroelectric power generation and is equipped with a carbon deposition plate containing a catalyst that promotes carbon deposition; and recovering solid carbon from the separated and recovered carbon dioxide gas by precipitating solid carbon from the carbon monoxide gas.

7. A method for recovering solid carbon utilizing renewable energy, characterized in that the carbon deposition plate according to claim 6 is equipped with an ultrasonic vibrator driven by renewable energy electricity obtained from geothermal power generation or hydroelectric power generation, and carbon is deposited on the carbon deposition plate while vibrating at high frequency, thereby continuously depositing and recovering carbon while peeling off and removing the carbon deposited on the carbon deposition plate.

8. A renewable energy-based solid carbon recovery method, characterized in that the molten salt electrolysis device according to claim 4 or the gas reactor according to claim 6 is provided with a mechanism for continuously discharging precipitated solid carbon by a solid carbon discharge mechanism driven by renewable energy electricity obtained from geothermal power generation or hydroelectric power generation, thereby preventing blockages due to carbon deposition in the molten salt electrolysis device and the gas reactor and continuously recovering solid carbon while maintaining a stable reaction.

9. 1. A method for recovering hydrogen gas utilizing renewable energy, comprising: mixing biomethane obtained when carbon dioxide is separated and recovered from biogas by the method of claim 1 with steam obtained by evaporating water by heating with geothermal steam or an electric heater using electricity from geothermal or hydroelectric power generation; supplying the resulting mixture to a steam reforming catalyst heated by an electric heater using electricity from geothermal or hydroelectric power generation to carry out steam reforming; generating a mixture of hydrogen, carbon dioxide, and steam by a transformation reaction of carbon monoxide gas; cooling and dehumidifying the mixture; and supplying the mixture to a carbon dioxide separation membrane to separate and recover the carbon dioxide, thereby recovering hydrogen gas originating from biogas.

10. A renewable energy-utilizing solid carbon recovery system that applies any one or more of the renewable energy-utilizing carbon dioxide separation and recovery methods described in claims 1 to 3 and any one or more of the solid carbon recovery methods described in claims 4 to 8.

11. A renewable energy-utilizing carbon monoxide gas recovery system that recovers carbon monoxide gas from separated and recovered carbon dioxide gas using one or more of the renewable energy-utilizing carbon dioxide separation and recovery methods described in claims 1 to 3 and the method described in claim 4 or 5.

12. A renewable energy-based hydrogen gas recovery system that separates and recovers carbon dioxide from biogas and then recovers it as hydrogen gas by applying one or more of the renewable energy-based carbon dioxide separation and recovery methods described in claims 1 to 3 and the hydrogen gas recovery method described in claim 9.

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