JP7390747B2 - Hydrogen production device and method, electric hydrogen co-production system, and method for decomposing carbon dioxide - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act On March 18, 2020, the "NIFS Study Group", the "In-core Equipment/Materials/System Integration Study Group for Demo Reactor", and the "COE for Cross-sectional Research" were established. Presented at a ZOOM meeting by the joint research group of the ``Oroshihi-2 Utilization Study Group'' (https://kyoto-u-edu.zoom.us/j/89841379798?pwd=d0NPY25zaW9kNTZVZ0xYdUtucmFPQT0 9)

The present invention relates to a hydrogen production device and method , a power hydrogen co-production system, and a method for decomposing carbon dioxide , and more specifically, a hydrogen production device and method for producing hydrogen from water raw material by radiation induction using carbon dioxide as a circulating catalyst. The present invention relates to a method , a power hydrogen co-production system , and a method for decomposing carbon dioxide .

Global warming caused by carbon dioxide released into the atmosphere due to the use of carbon-based fossil fuels such as oil and coal is a worldwide problem. Therefore, in Japan, large-scale use of hydrogen energy as an alternative energy source has been proposed as a countermeasure. However, in Japan, the existing core technologies and conditions for large-scale hydrogen production are not in place, so hydrogen produced using electrolysis technology is more expensive than conventional energy sources. For this reason, measures are being taken to transport large quantities of hydrogen derivatives produced overseas domestically, but there are problems with cost fluctuations and supply stability such as regular supply.

Therefore, in the transition to a hydrogen-based society in Japan, the establishment of domestic production technology and cost reduction for hydrogen production will become major issues in the future. For example, it is already known that the technology for producing hydrogen using carbon dioxide from water resources is possible by combining the following reactions (1) and (2) (Non-Patent Documents 1 to 3).
(1) At a high temperature of 1100℃, carbon dioxide is decomposed into carbon monoxide and oxygen molecules through a reduction reaction.
(2) Producing hydrogen from carbon monoxide and water using a catalyst (water gas shift reaction)
However, in (1) above, since a high temperature range of 1100° C. is used, the production of hydrogen in large quantities is expensive, and it has not been put to practical use except for special purposes. As a countermeasure to this high temperature, the carbon monoxide decomposition reaction of carbon dioxide in the intermediate temperature range using radiation is already well known, but its decomposition efficiency is about 0.1%, and as mentioned above, there is no prospect of practical application. Not standing.

On the other hand, apart from the above-mentioned issues regarding hydrogen production, the issue of storage and long-term storage of high-level waste, which is a source of high-intensity radiation and is generated during the reprocessing of spent nuclear fuel from nuclear power plants, is one of the causes of great anxiety and stress among the public. It has become. In addition, even in nuclear fusion reactors, which are expected to be a future energy source, there are major issues such as dealing with high-energy neutrons generated as a result of the DT reaction and solving problems by using cooling water. Furthermore, there is a need to develop a means to solve the radiant energy loss in solar power generation and a power generation system that utilizes high-temperature geothermal heat from deep underground magma layers.

P. Harteck and S. Dondes, J. Chem: Phys., 26, 1727 (1957) N. Fujita and C. Matsuura: Radiation induced reduction of CO2 in iron containing solution, Radiat. Phys. Chem., 43, 205 (1994) X.-Z. Wu, et al.: Chem. Lett., 2000, 572-573.

The present invention has been made in view of the above facts, and uses existing or future heat sources conventionally used as power generation or heat sources, or the heat sources and unnecessary radiation as an induction catalyst, and is a cause of global warming. A hydrogen production device that makes it possible to reduce and decompose certain unnecessary carbon dioxide into carbon monoxide, and then to inexpensively produce a large amount of hydrogen from the decomposed carbon monoxide and water resources using a water gas shift reaction. The purpose is to provide a power and hydrogen co-production system and a hydrogen production method.

In order to solve the above problems, the hydrogen production device of the present invention uses heat or heat and radiation to cause a CO ₂ thermal decomposition reaction to decompose supercritical CO ₂ into CO and O ₂ . A water gas shift reaction section that generates H ₂ and CO ₂ by causing a water gas shift reaction between the CO ₂ decomposition section and the CO and H ₂ O decomposed in the supercritical CO ₂ decomposition section. It has been prepared and configured.

For example, the supercritical CO ₂ decomposition section is arranged to receive heat from an external heat source, or heat from an external heat source and radiation from an external radiation source, and supercritical CO ₂ is introduced. Equipped with _CO2 piping.

Preferably, the apparatus further includes a supercritical CO 2 circulation path for returning the CO ₂ generated by the water gas shift reaction section to the supercritical CO _{2 decomposition} section in a supercritical state.
The CO ₂ piping is arranged to receive heat from an external heat source and radiation from an external radiation source, the external heat source being a medium temperature range heat source. Alternatively, the CO ₂ pipe is arranged to receive heat from an external heat source, and the external heat source is a high temperature range heat source of 1100° C. or higher.

For example, the external heat source and the external radiation source are storage pipes containing high-level radioactive waste, and the CO ₂ piping is piping arranged to surround the storage pipe. For example, the external heat source is a heating heater, and the external radiation source is ^{a 60} CO radiation source. For example, the external heat source and external radiation source are nuclear power reactors. For example, the nuclear power reactor includes a molten salt circulation path through which molten salt circulates for transferring heat generated in the core of the nuclear power reactor, and the CO ₂ pipe is disposed within the molten salt circulation path. Ru.

The external heat source or the external heat source and external radiation source may be a fusion power reactor. Specifically, the CO ₂ pipe is configured as a pipe that cools a blanket of the fusion power reactor, and preferably the blanket includes a radiation/neutron multiplier. Alternatively, the CO ₂ piping is configured as a piping that cools a diverter of the fusion power reactor, and preferably, the diverter is configured from a plurality of diverter cassettes. The diverter cassette may include a tungsten plate arranged to receive heat radiated from the core plasma of the fusion power reactor, and the CO ₂ pipe connected to the back side of the plate. good. Preferably, the CO ₂ pipe connected to the back side of the plate is composed of a plurality of pipes. More preferably, the CO ₂ pipe is configured to exchange heat between an inlet pipe for supercritical CO ₂ input to the diverter, an outlet pipe for gas output from the diverter, and the inlet pipe and the outlet pipe. It is equipped with a heat exchanger that performs

In another example, the CO ₂ pipe is arranged in a heat collecting part where sunlight is collected. Yet another example of _CO2 piping is placed underground to receive heat from a magma layer.
Preferably, the water gas shift reaction section includes magnetite (Fe ₃ O ₄ ) or ferric oxide (Fe ₂ O ₃ ) as a catalyst.

The power and hydrogen co-production system of the present invention generates electricity by circulating the above-described hydrogen production device, the fusion power reactor, and supercritical CO ₂ heated by the fusion power reactor to rotate a gas turbine. A power generation device.

Another example of the power-hydrogen co-production system of the present invention includes a power generation device using supercritical CO ₂ disposed in the supercritical CO ₂ circulation path of a nuclear power reactor. Further, the power generation device may include a power generation device that generates power using gas containing CO, CO ₂ and O ₂ discharged from the CO ₂ pipe of the supercritical CO ₂ decomposition unit , and the power generation device The gas used for power generation is supplied to the water gas shift reaction section, and the CO ₂ generated in the water gas shift reaction section is reused and returned to the CO ₂ pipe. It may also include a second CO ₂ pipe for supercritical CO ₂ disposed in the molten salt circulation path, and a power generation device using supercritical CO ₂ flowing through the second CO ₂ pipe. , in this case, preferably said second CO ₂ pipe is covered with a shielding blanket that shields radiation.

Yet another example of the power and hydrogen co-production system of the present invention includes a hydrogen production device equipped with a CO ₂ pipe heated by a solar heat collecting section as a supercritical CO ₂ decomposition section , and a hydrogen production device that uses the heat of the heat collecting section to A power generation device that generates electricity using heated supercritical CO ₂ ;
Equipped with.

A hydrogen co-production system according to yet another example of the present invention includes a hydrogen production device equipped with a CO ₂ pipe buried deep underground to be heated by the heat of a magma layer as a supercritical CO ₂ decomposition unit ; It also includes a power generation device that also generates electricity using supercritical CO ₂ .

The hydrogen production method of the present invention decomposes supercritical CO2 _{into CO} and oxygen by applying heat or heat and radiation to supercritical CO2 , adds water to the decomposed carbon monoxide, and shifts the water gas. It is configured to include each step of generating H ₂ and CO ₂ by causing a reaction, and circulating the CO ₂ by returning the generated CO ₂ in a supercritical state to the decomposition step.

FIG. 1 is a schematic diagram of a hydrogen production apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of a hydrogen production apparatus according to a second embodiment of the present invention. FIG. 3 is a conceptual diagram of the hydrogen production method of the present invention. FIG. 4 is a diagram showing the flow of measurement of CO ₂ /CO decomposition efficiency in a supercritical state by high-temperature ⁶⁰ Co irradiation. FIG. 5 is a graph of the measurement results of CO ₂ /CO decomposition efficiency in a supercritical state by ⁶⁰ Co high-temperature irradiation. FIG. 6 is a conceptual diagram illustrating the effects of the present invention in comparison with the prior art. FIG. 7 is a conceptual diagram illustrating the principle of the present invention in comparison with the prior art. FIG. 8 is a diagram showing a supercritical CO ₂ decomposition unit according to aspect 1 (utilization of high-level waste) of the first embodiment of the present invention. FIG. 9 is a diagram showing an electric power hydrogen co-production system (first modification) including a hydrogen production device according to aspect 2 (utilization of a nuclear power reactor) of the first embodiment of the present invention. FIG. 10 is a diagram showing an electric power hydrogen co-production system (second modification) including a hydrogen production device according to aspect 2 (utilization of a nuclear power reactor) of the first embodiment of the present invention. FIG. 11 is a diagram showing the structure of a fusion power reactor (aspect 3) used as an external heat source in the first or second embodiment of the present invention. FIG. 12 is a diagram showing a detailed configuration (first modification of aspect 3) of the blanket of the fusion power reactor of FIG. 11 to which the supercritical CO ₂ decomposition section (aspect 3) of the hydrogen production apparatus of the present invention is applied. It is an enlarged view of the part. FIG. 13 is a diagram showing a detailed configuration (second modification of aspect 3) of the diverter of the fusion power reactor of FIG. 11 to which the supercritical CO ₂ decomposition section of the hydrogen production apparatus of the present invention is applied. FIG. 14 is a schematic diagram showing the configuration of CO ₂ piping of the supercritical CO ₂ decomposition section provided in the diverter of FIG. 13. FIG. 15 is a graph showing the relationship of outlet temperature to supercritical CO ₂ inlet velocity to the diverter of FIG. 14. FIG. 16 is a perspective view showing the basic configuration of one CO ₂ pipe of the supercritical CO 2 decomposition section provided in the diverter of FIG. 15, and (a) shows the CO ₂ pipe in a state where supercritical CO ₂ flows _. , (b) shows only the piping section of the CO ₂ piping, (c) shows the tungsten plate that receives heat load from the core plasma, and (d) shows the shape of the CO ₂ gas flowing through the piping section of the CO ₂ piping. show. FIG. 17 is a perspective view showing a specific configuration of the CO ₂ piping of the supercritical CO ₂ decomposition section provided in the diverter of FIG. 15, and (a) to (e) each show a different example. FIG. 18 is a diagram showing an electric power hydrogen co-production system including a hydrogen production device (second modification of aspect 3) having a supercritical CO ₂ decomposition section provided in the diverter of FIG. 14. FIG. 19 is a diagram showing an electric power hydrogen co-production system including a hydrogen production device (second embodiment) that uses sunlight as a heat source. FIG. 20 is a diagram showing a power-hydrogen co-production system including a hydrogen production device (second embodiment) that utilizes a high-temperature magma layer deep underground as a heat source.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings.
<First embodiment>
FIG. 1 is a schematic diagram of a hydrogen production apparatus according to a first embodiment of the present invention.

As shown in FIG. 1, the hydrogen production apparatus 1 according to the first embodiment is a supercritical CO2 decomposition unit 2 into which supercritical CO2 _is introduced , _and uses heat and radiation to decompose supercritical CO2 _. The supercritical CO2 _{decomposition} unit 2 promotes the _CO2 thermal decomposition reaction to decompose CO2 into CO and oxygen, and water is added to the carbon monoxide decomposed in the supercritical CO2 _{decomposition} unit 2 to cause a water gas shift reaction. a water gas shift reaction section 3 which generates H ₂ and CO ₂ .

Preferably, the hydrogen production apparatus 1 includes a first circulation path 4 for transporting gas containing CO from the supercritical CO ₂ decomposition unit 2 to the water gas shift reaction unit 3, and a hydrogen gas produced by the water gas shift reaction unit 3. It further includes a second circulation path 10 that returns CO ₂ in a supercritical state to the supercritical CO ₂ decomposition unit 2 . Preferably, when the CO ₂ gas is no longer in a supercritical state in each of the above-mentioned reactions, the CO ₂ gas flowing through the second circulation path 10 is returned to supercritical CO ₂ by pressurizing or heating the CO 2 gas. A criticalization mechanism 11 is provided.

Further, preferably, the water gas shift reaction section 3 includes magnetite (Fe ₃ O ₄ ) or ferric oxide (Fe ₂ O ₃ ) as a catalyst for the water gas shift reaction.
The supercritical CO ₂ decomposition unit 2 is arranged to receive heat from an external heat source 5 and radiation from an external radiation source 6 . The external heat source 5 is, for example, a medium temperature heat source of 800° C. or lower, but is not limited thereto. Examples of the radiation source 6 include, but are not limited to, sources of neutrons, electron beams, gamma rays, and alpha rays. The heat source 5 and the radiation source 6 may be separate sources, or may be one source 7 such as a nuclear power reactor or a nuclear fusion power reactor, which will be described later.

The CO ₂ thermal decomposition reaction caused in the supercritical CO ₂ decomposition unit 2 is as follows.
CO2 +566kJ/mol→CO+1 _{/ 2O2}
Therefore, in the supercritical CO ₂ decomposition unit 2, carbon monoxide CO and oxygen O ₂ are generated. In reality, the gas discharged from the supercritical CO ₂ decomposition unit 2 also includes undecomposed CO ₂ . Preferably, the hydrogen production device 1 includes a dry pump/turbo-molecular pump (not shown) for discharging decomposed carbon monoxide CO and oxygen O ₂ from the supercritical CO ₂ decomposition unit 2; It includes a first separation section 8 that separates carbon monoxide CO and oxygen _O2 . The separation unit 8 has, for example, a CO adsorbent (e.g. zeolite) that adsorbs CO with high selectivity or a getter material that separates and recovers CO, and separates unadsorbed gas as _O2 , or vice versa. Furthermore, the separation section 8 may be made of a material that adsorbs O ₂ with high adsorption properties. In any case, the present invention does not limit the configuration of the first separating section 8. Further, the separation unit 8 may separate CO ₂ gas that has not been decomposed by the supercritical CO ₂ decomposition unit 2 from other gases. This separated CO ₂ gas may be directly returned to the second circulation path 10 without passing through the water gas shift reaction section 3 .

The CO separated in the separation section 8 is introduced into the water gas shift reaction section 3. Furthermore, water is supplied to the water gas shift reaction section 3. In the water gas shift reaction section 3, the following water gas shift reaction process is caused between CO and _H2O introduced from the separation section 8.

CO+ _H2O → _CO2 + _H2 +41.2kJ/mol
That is, the water gas shift reaction section 3 generates carbon dioxide CO ₂ and hydrogen H ₂ . As the second separation section 9 that separates carbon dioxide CO ₂ and hydrogen H ₂ , in the water gas shift reaction section 3 , for example, argon Ar, which is an inert gas, is introduced/exhausted to generate a flow of Ar. , a mechanism in which carbon dioxide CO ₂ and hydrogen H ₂ carried by the flow are separated due to a difference in specific gravity can be considered, but the present invention does not limit the configuration of the second separation section 9. The carbon dioxide CO ₂ separated as described above is returned to the second circulation path 10. The separated H ₂ is taken out as a hydrogen resource.

According to the hydrogen production device 1 according to the first embodiment of the present invention, the CO ₂ thermal decomposition reaction is promoted by applying heat and radiation to supercritical CO ₂ , so CO 2 is produced with higher efficiency than before. It becomes possible to separate. This decomposition efficiency will be explained below based on measurement results.
(Measurement of CO ₂ /CO decomposition efficiency in supercritical state by ⁶⁰ Co high temperature irradiation)
Figure 4 shows the flow of measuring the CO ₂ /CO decomposition efficiency in a supercritical state using ⁶⁰ Co high-temperature irradiation. As shown in FIG. 4, first, a cylinder is filled with subcritical CO ₂ gas that is not in a critical state. The CO ₂ critical temperature is 304.1 K (31.1° C.) and the CO ₂ critical pressure is 7.38 MPa. For example, CO ₂ gas is sealed at 25° C. and a pressure of 7.38 MPa. Although the pressure is the critical pressure, the temperature is lower than the critical temperature, so the CO ₂ gas sealed in the cylinder is in a subcritical state.

Next, the cylinder filled with subcritical CO ₂ gas was heated with a heater, and ⁶⁰ Co, which irradiated with 10 kGy/h of gamma rays (1.1 to 1.3 MeV), was placed near the cylinder. Heating temperatures of 200°C, 400°C, and 600°C were selected, and each heating temperature was continued, and the concentration of CO decomposed in the cylinder was measured at several times between 0 and 60 minutes. , the CO/CO ₂ ratio was determined.

FIG. 5 shows a graph of the measurement results of CO ₂ /CO decomposition efficiency in a supercritical state by ⁶⁰ Co high-temperature irradiation. For comparison, the measurement results when the cylinder was not heated and the temperature was maintained at 25° C., that is, the measurement results of subcritical CO ₂ are also shown. As shown in the graph of Figure 5, in the subcritical CO ₂ measurement results ( at 25°C ), the CO/CO ₂ ratio increases rapidly within a short time after the start of the measurement, but after that, it increases. It remains at about 10% until the end of the measurement. On the other hand, at temperatures of 200°C, 400°C, and 600°C, the CO ₂ in the cylinder is considered to be in a supercritical state, and the CO/CO ₂ ratio rapidly increases within a short period of time after the start of measurement. increased, and thereafter a transition state was observed that gradually increased to 24%, 27%, and 45%, respectively, until 1000 seconds. After 1000 seconds, the CO/CO ₂ ratio maintained a substantially constant value until the end of the measurement. This stable state is thought to be due to the self-shielding effect of decomposed CO against irradiated γ-rays, the CO--O recombination reaction, and the lack of radiation energy.

From the measurement results in FIG. 5, it can be seen that under radiation irradiation, by bringing CO ₂ into a supercritical state, it increases significantly compared to the conventional technology, and as the temperature becomes higher, the CO/CO ₂ ratio increases. It was shown that the increase in Therefore, by configuring the hydrogen production apparatus 1 in which ^the heat source ₅ in FIG. 1 is replaced by the heating heater in FIG. Therefore, it can be understood that the hydrogen production efficiency can be significantly improved.

FIG. 6 shows the differences in the CO ₂ pyrolysis reaction process between the prior art and the present invention.
As shown in FIG. 6, in the conventional CO ₂ thermal decomposition reaction process using flow-through electron beam irradiation (1.2×10 ¹⁷ eV/cm ³ s), the G value of the product from CO ₂ in a subcritical state is (The number of chemical reaction products generated when 100 eV of energy is absorbed) was 8 at 20°C, and was about 13 even when the temperature was raised to 500°C. Further, the CO/CO ₂ ratio is about 0.1%. In contrast, in the present invention , the G value of the product from supercritical CO ₂ is 1300 at 50° C., and the CO/CO ₂ ratio increases to several tens of percent.

The reason why the radiolysis effect is significantly improved by making CO ₂ supercritical will be discussed using FIG. 7. As shown in FIG. 7, it is estimated that the probability of encountering radiation is low in the normal CO ₂ noble gas state. On the other hand, in the _CO2 supercritical state, the density is high and interatomic vibrations are intense, so it is assumed that the probability of encountering radiation increases and the efficiency of cutting the O-C-O bond chain increases. Ru.

Therefore, as shown in FIG. 3, the hydrogen production method of the present invention decomposes supercritical CO2 _into CO and oxygen by applying heat and radiation to the supercritical CO2 _, and decomposes the decomposed monoxide. Each process includes adding water to carbon to cause a water gas shift reaction to generate _H2 and _CO2 , and circulating the _CO2 by returning the generated _CO2 in a supercritical state to the decomposition process. It can be configured as follows.

It goes without saying that the examples of the heat source 5 and the radiation source 6, or a single source 7 that integrates both, are not limited to the above examples, and at least the following aspects are possible. Note that in each aspect, constituent elements similar to those in FIG. 1 are given alphabetical suffixes a, b, c, and d for each aspect to the reference numbers used in FIG. 1, and detailed description thereof will be omitted.
(Aspect 1 - Using high-level radioactive waste as a heat source and radiation source)
FIG. 8 shows a supercritical CO ₂ decomposition unit 2a according to aspect 1. As shown in FIG. 8, the supercritical CO ₂ decomposition unit 2a is provided in a facility 22 for high-level radioactive waste, and within the facility 22 there is a storage pipe 20 containing high-level radioactive waste. A plurality of are arranged, and these serve as a heat source and a radiation source 7a that irradiate heat and radiation. In each of the storage tubes 20, a plurality of vitrified bodies 21 filled with high-level radioactive waste are arranged in series. A CO ₂ pipe 2 a serving as a supercritical CO ₂ decomposition unit is provided so as to surround each storage pipe 20 . By introducing supercritical CO ₂ into the CO ₂ pipe 2a, the supercritical CO ₂ flowing through the CO ₂ pipe 2a is decomposed by the heat and radiation irradiated from the storage pipe 20 promoting the CO ₂ thermal decomposition reaction. The CO produced is transported to the water gas shift reaction section 3 (FIG. 1).

In aspect 1, it becomes possible to store high-level radioactive waste more safely and to produce hydrogen at zero cost.
(Aspect 2 - Using a nuclear power reactor as a heat source and radiation source)
In FIG. 9, a nuclear power reactor 7b is shown as an integrated source of an external heat source 5b and an external radiation source 6b. The nuclear power reactor 7b includes a reactor core 30, a molten salt circulation path 31 through which molten salt circulates for transferring heat generated in the reactor core 30, and a motor-equipped pump 32 for circulating solvent salt within the path 31. Equipped with. Inside the molten salt circulation path 31, a CO ₂ pipe 2b serving as a supercritical CO ₂ decomposition section is arranged. By introducing supercritical CO ₂ into the CO ₂ pipe 2b, the supercritical CO ₂ flowing through the CO ₂ pipe 2b is caused by the heat of the reactor core 30 transferred via the solvent salt and the radiation irradiated from the reactor core 30. The CO ₂ thermal decomposition reaction is promoted, and the decomposed CO is transported to the water gas shift reaction section 3b.

Furthermore, the system 100 shown in FIG. 9 not only uses a hydrogen production device but also processes CO, CO 2 and O ₂ discharged from the CO ₂ piping 2b of the supercritical CO ₂ decomposition unit through the first circulation path _4b . It includes a power generation device 35 that generates power using the gas contained therein. The power generation device 35 supplies the gas used for power generation to the water gas shift reaction section 3b, reuses the CO ₂ generated in the water gas shift reaction section 3b, and supplies the CO 2 to the CO ₂ piping 2b via the second circulation path 10b. Return to

The power generation device 35 includes a gas turbine section 36 having compressors MC, BC, and a turbine G that are uniaxially connected, and generates electricity by rotating the gas turbine section 36 with gas containing CO, _CO2, and _O2 . Can be done.

Further, a second pipe 33 may be disposed within the molten salt circulation path 31, and can be used to perform power generation using steam, which is normally performed in a nuclear power reactor.
As described above, the system 100 shown in FIG. 9 constitutes a power-hydrogen co-production system (first modification) that produces hydrogen and generates power.

FIG. 10 shows an electric power and hydrogen co-production system 101 according to a second modification. In the power-hydrogen co-production system 101, the power generation device 35 is not provided in the first circulation path 4c and the second circulation path 10c as in the first modification, but in the second circulation path where supercritical CO ₂ is circulated. It is connected to the piping 33c. Since the second pipe 33c is arranged in the circulation path 31 of molten salt heated by the nuclear power reactor 7c, the power generation device 35 can efficiently generate power using heated supercritical CO2 _. becomes. Since the power generation device 35 does not require decomposed CO, in the second modification, the second pipe 33c is covered with a shielding shield 34 that shields radiation from the core 30 of the nuclear power reactor 7c. It is preferable to be there.
(Aspect 3 - Using a fusion power reactor as a heat source and radiation source)
In FIG. 11, a fusion power reactor 7d is shown as an integrated source of an external heat source 5d and an external radiation source 6d. The fusion power reactor 7d is a tokamak-type fusion power reactor, and includes a plasma vacuum vessel 40 for confining core plasma 50, a superconducting helical coil 41 and a superconducting poloidal coil 42 for generating a magnetic field for confining the plasma 50. , an electromagnetic force support structure 43, a cryostat (insulated vacuum vessel) 44 forming an exterior part, a blanket 45 provided on the inner wall of the vacuum vessel 40 to surround the plasma 50, and efficient exhaust heat and exhaust impurity particles. and a diverter 46 for forming a magnetic field configuration in which the plasma particles are concentrated to enable.

In embodiment 3, the CO ₂ gas piping of the supercritical CO ₂ decomposition unit is provided in the blanket 45, which is subjected to a high heat load in the fusion power reactor 7d (first modification), or the CO 2 gas piping is installed in the diverter 46 (the first modification) which has the highest temperature. 2) may be provided. Each modification will be explained below.

FIG. 12 shows a partially enlarged view of the blanket 45 of the fusion power reactor of FIG. 11 to which the supercritical CO ₂ decomposition unit 2d of the first modification of aspect 3 is applied. As shown, the blanket 45 is provided on the inner wall of the plasma vacuum vessel 40 facing the core plasma 50. The blanket 45 receives high-temperature radiation from the plasma 50 and therefore becomes high in temperature, so a cooling mechanism is essential. Conventionally, cooling using cooling water has been considered, but in the present invention, a supercritical CO ₂ decomposition unit 2d is provided as a cooling means for the blanket 45.

The supercritical CO ₂ decomposition unit 2d is configured as a cooling pipe (not shown) provided on the back side of the blanket 45. An inlet pipe 48 for supercritical CO ₂ and an outlet pipe 49 for gas flowing through the cooling pipe are connected to the cooling pipe. The supercritical CO ₂ introduced from the inlet pipe 48 flows through the cooling pipe of the blanket, and at this time, the heat and neutrons emitted from the plasma 50 cause a thermal decomposition reaction to become a gas containing CO, which is then released from the outlet pipe 49. to go out. The CO-containing gas discharged from the outlet pipe 49 is guided to the water gas shift reaction section.

Preferably, the blanket 45 includes radiation/neutron multiplier 47 . This makes it possible to increase radiation including neutrons and further promote the CO ₂ thermal decomposition reaction in the cooling pipe.

FIG. 13 shows a perspective view of the diverter 46 of the fusion power reactor of FIG. 11 to which the supercritical CO ₂ decomposition unit 2e of the second modification of aspect 3 is applied. As illustrated, the diverter 46 is configured by laying a plurality of diverter cassettes 51. Each of the diverter cassettes 51 is independently replaceable, facilitating repair work in the event of damage. Note that FIG. 13 shows a cooling water pipe 52 and a pipe connection portion 53 for the plasma vacuum vessel 40.

FIG. 14 shows a schematic diagram of the supercritical CO ₂ decomposition section 2e. As illustrated, the supercritical CO ₂ decomposition unit 2e is configured as a cooling pipe 70 (CO ₂ pipe) that cools the diverter 46 or the diverter cassette 51, and specifically receives high temperature heat load from plasma. It is configured as a supercritical CO ₂ cooling pipe (described later) disposed on the back side of the surface plate 72 of the diverter 46 or the diverter cassette 51. The cooling pipe 70 is connected to an inlet pipe 56 for supercritical CO ₂ and an outlet pipe 57 for gas containing CO flowing through the cooling pipe. The supercritical CO ₂ introduced from the inlet pipe 56 flows through the cooling pipe 70 of the divertor, and at this time, the heat and neutrons radiated from the plasma 50 cause a thermal decomposition reaction, resulting in a high-temperature gas containing CO. 57 and exits the diverter.

FIG. 15 shows the results of a simulation of the relationship between the gas temperature at the inlet and outlet of the cooling pipe 70 and the temperature of the surface plate 72 with respect to the inlet velocity of supercritical CO ₂ in the cooling pipe 70. As shown in the graph of FIG. 15 , for example, at an inlet speed of 200 m/s, the inlet temperature was 1200K and the outlet temperature was 1373K. Further, the maximum surface temperature of the surface plate 72 was about 3000K, and the average surface temperature was about 2800K. Therefore, if tungsten is used as the material for the surface plate 72, melting of the surface plate can be prevented since its melting point is lower than the maximum surface temperature shown in FIG. Therefore, a sufficient cooling effect by supercritical CO ₂ was confirmed.

Preferably, the supercritical CO ₂ decomposition unit 2e further includes a heat exchanger 55 that exchanges heat between an inlet pipe 56 and an outlet pipe 57. The heat exchanger 55 is provided with an inlet port 58 that communicates with the inlet pipe 56 and an outlet port 59 that communicates with the outlet pipe 57. While the supercritical CO ₂ introduced from the inlet port 58 passes through the inlet pipe 56 in the heat exchanger 55, it is heated by the outlet pipe 57 through which gas containing higher-temperature CO flows, reaching a higher temperature and passing through the diverter. The plasma flows into the cooling pipe 70, is further heated by the heat from the plasma, and exits from the diverter through the outlet pipe 57. The CO-containing gas flowing through outlet line 57 is cooled in heat exchanger 55 by heating the supercritical CO ₂ flowing through inlet line 56 and exits through outlet port 59 . According to the simulation, if the temperature of supercritical CO ₂ introduced into the inlet port of the heat exchanger 55 is set to 350K, the temperature will rise to 1200K by the heat exchanger 55, and further rise to 1373K after passing through the cooling pipe 70. It is heated and then cooled to 350K by heat exchanger 55. According to this preferred embodiment, it becomes possible to more easily handle gas at a temperature of 350K.

FIG. 16 shows the basic configuration and each component of the cooling pipe 70. As shown in FIG. 16(a), the cooling piping 70 includes a piping portion 71 (FIG. 16(b)) and a tungsten surface plate 72 (FIG. 16(c)) connected to the upper surface of the piping portion 71. It is equipped with Supercritical CO ₂ 73 having the shape shown in FIG. 16(d) flows through the cooling pipe 70.

FIG. 17 shows a plurality of more specific modifications of the cooling pipe 70 (CO ₂ pipe). Note that in FIGS. 17A to 17E, corresponding constituent elements are given the same reference numerals, alphabetical subscripts are used to distinguish each example, and only different parts will be described.

As shown in FIG. 17(a), the cooling pipe 70a includes a plurality of pipe parts 71a arranged in parallel, a tungsten surface plate 71a connected across the upper surface of the plurality of pipe parts 71a, and a plurality of tungsten surface plates 71a connected across the upper surfaces of the plurality of pipe parts 71a. An inlet manifold 74a connected to one end of the plurality of piping sections 71a for introducing supercritical CO ₂ into the plurality of piping sections 71a, and an inlet manifold 74a connected to one end of the plurality of piping sections 71a for discharging gas containing CO from the plurality of piping sections 71a. and an outlet manifold 75a connected to the other end. The inlet manifold 74a is formed with three inlet ports for supercritical CO2 _, and the outlet manifold 75a is provided with one outlet port for gas containing CO. The inlet port communicates with inlet piping 56, and the outlet port communicates with outlet piping 57.

The cooling piping 70b shown in FIG. 17(b) differs from the cooling piping 70a shown in FIG. 17(a) in that the outlet manifold 75b has three outlet ports, but is otherwise the same.

In the cooling pipe 70c shown in FIG. 17(c), the inlet manifold 74c and the outlet manifold 75c are flatter than the cooling pipes 70a and 70b, and their shapes are also different. Further, the number of inlet ports of the inlet manifold 74c is one, and the number of outlet ports of the outlet manifold 75c is one.

The cooling pipe 70d shown in FIG. 17(d) is similar to the cooling pipe 70c, but the outlet manifold 75d has a plurality of outlet ports, and its shape is also different from the outlet manifold 75c of the cooling pipe 70c. ing.

In the cooling piping 70e shown in FIG. 17(e), the inlet manifold 74e is flat and has a plurality of inlet ports, and an outlet manifold is not provided, so that the ends of the plurality of piping portions 71a remain exposed. It becomes.

The supercritical CO ₂ decomposition unit 2 according to aspect 3 of the present invention uses CO ₂ gas as a cooling medium for cooling the blanket and diverter, and therefore has the following advantages compared to conventional cooling water.
(1) If high-pressure supercritical CO2 leaks into a vacuum container, the temperature will drop rapidly due to adiabatic expansion, so it will act as a fire extinguisher and will not cause damage to nearby high-temperature equipment. On the other hand, in the case of water, there is a risk of hydrogen/steam explosion or oxidation in some cases when it touches high-temperature equipment.
(2) When cooling water is used, tritium, which is a nuclear fusion fuel, may be mixed in or hydrogen may be converted to tritium by neutrons, so there is a risk of tritium contamination to the environment, but CO ₂ gas When using , that possibility does not exist.
(3) When cooling water is used, there is a risk of contamination due to the water adhering to the inner wall of the vacuum container, but when using _CO2 gas, there is little risk of such contamination.

FIG. 18 shows a hydrogen production system that includes a hydrogen production system according to aspect 3 (second modification) that utilizes a fusion power reactor as a heat source and a radiation source, and a power generation system 60 that uses supercritical CO2 _. A system 102 is shown.

In the power-hydrogen co-production system 102, hydrogen is produced by the hydrogen production device including the supercritical CO ₂ decomposition section 2e and the water gas shift reaction section 3e described above, and hydrogen is produced by the power generation device 60 using the heat of the fusion power reactor. Electricity is generated.

The power generation device 60 includes a main heat exchanger 61 that exchanges heat between supercritical CO ₂ and a molten salt circulation path 69 heated by the heat of the blanket 45 of the fusion power reactor. The power generation device 60 includes a low pressure compressor 62, a high pressure compressor 63, a bypass compressor 64, a gas turbine 65, and a generator 66 that are uniaxially connected. The supercritical CO ₂ heated by the main heat exchanger rotates the gas turbine 65 and compressors 62 to 64, thereby also rotating the generator 66 to generate electric power. Furthermore, the power generation device 60 includes a first regenerative heat exchanger 67a, a second regenerative heat exchanger 67b, a precooler 67c, and an intercooler 68.

In the power-hydrogen co-production system 102, heat exchange was performed between the molten salt circulation path 69 heated by the heat of the blanket 45 and the supercritical CO ₂ of the power generation device 60, but as shown in FIG. If a configuration in which supercritical CO ₂ is directly heated by the heat of the blanket 45 is used in the power generation device 60, it becomes possible to more efficiently generate electricity using the directly heated supercritical CO ₂ .

According to the power-hydrogen co-production system 102, it is possible to not only generate electricity through the DT reaction between deuterium (D) and tritium (tritium T) in a conventional fusion power reactor, but also to produce hydrogen. Become. In conventional DT reaction fusion power reactors, deuterium (D) and lithium (Li) are used as raw fuel and tritium (tritium T) is produced from lithium (Li), but the temperature of the core plasma is further increased. It is expected that increasing the temperature will enable nuclear fusion power generation by fusion of hydrogen (H) and hydrogen (H) in the future. In this case, by using the hydrogen produced by the hydrogen production apparatus of the present invention as a nuclear fusion fuel, it is possible to realize the ultimate nuclear fusion power reactor that does not require a fuel supply.
<Second embodiment>
FIG. 2 is a schematic diagram of a hydrogen production apparatus 1b according to a second embodiment of the present invention. In FIG. 2, constituent elements similar to those in the first embodiment of FIG. 1 are given the same reference numerals, detailed explanations are omitted, and only different constituent elements will be explained. A hydrogen production apparatus 1b according to the second embodiment shown in FIG. 2 includes a heat source 12 in a high temperature range of 1100° C. or higher. For this reason, it is considered that the CO ₂ thermal decomposition reaction of supercritical CO ₂ can be promoted without radiation irradiation, so the radiation source used together with the heat source in the first embodiment can be omitted. However, a radiation source 13 may be provided to further promote the CO ₂ thermal decomposition reaction, or a single source 14 serving as both the heat source 12 and the radiation source 13 may be provided. An example of one source 14 is one that uses a diverter or the like that enables heating in a high temperature range in a fusion reactor that performs nuclear fusion between elements that generate high-energy neutrons (therefore, the source 14 in FIG. The hydrogen production device shown can also be interpreted as the second embodiment).

An example of only the heat source 12 is a nuclear fusion reactor that performs nuclear fusion between elements that do not generate high-energy neutrons, using a diverter or the like that enables heating in a high temperature range.

Other examples of CO ₂ decomposition using only the heat of the heat source 12 shown in FIG. 2 include sunlight and a heat source in a high-temperature magma layer deep underground, which will be described below.
(Mode of using sunlight)
FIG. 19 shows an electric and hydrogen co-production system 103 according to a second embodiment of the present invention (an example that uses sunlight). In the power and hydrogen co-production system 103, sunlight reflected by one or more mirrors is concentrated in one place to achieve a high temperature range.

As shown in FIG. 19, the power and hydrogen co-production system 103 includes a tower 80 having a heat collecting section 12a as a heat source, and a plurality of heliostats 83 having mirrors that reflect sunlight toward the heat collecting section 12a. , CO ₂ piping 2f as a supercritical CO ₂ decomposition section provided in the heat collection section 12a, circulation paths 4f and 10f for supercritical CO ₂ and CO, and CO 2 decomposed in the heat collection section 12a in the high temperature range. and a water gas shift reaction section 3f using gas containing CO. The heliostat 83 is placed around the tower 80, for example on the ground, and can automatically change its direction according to the movement of the sun on the celestial sphere. As a result, as long as the sun is out, the heat collecting section 81 is continuously irradiated with sunlight as well as sunlight reflected from the heliostat 83.

In addition, by providing a daytime power generation unit (not shown, see power generation device 35 in FIGS. 9 and 10) that generates power using gas containing CO ₂ /CO flowing through the circulation paths 4f and 10f, power generation is performed during the daytime. becomes possible.

The power and hydrogen co-production system 103 includes a pipe 82 that circulates molten salt (for example, FLiNaK) heated by the heat collecting part 12a, and a power generation part 81 connected to the pipe 82. The power generation section 81 includes a high-temperature molten salt tank 84 that stores heated FLiNaK sent from a pipe 82, and a heat exchanger 86 that exchanges heat between the FLiNaK from the high-temperature molten salt tank 84 and supercritical CO2 _. , a power generation device 60 (see FIG. 18) that generates electricity using supercritical CO ₂ heated by heat exchange, and a low-temperature generator that supplies heat to supercritical CO ₂ in a main heat exchanger 86 and stores the low-temperature FLiNaK. A molten salt tank 85 is provided. In addition, in the power generation section 81, supercritical CO2 _heated in the heat collecting section 12a may be circulated through the pipe 82 instead of the molten salt. Thereby, the power generation device 60 can also more efficiently generate power using supercritical CO ₂ directly heated by the heat collecting portion 12a. Even at night when the sun is setting or in cloudy/rainy/snowy weather when the sun is not out, the power generation unit 81 can generate electricity using the heat stored in the molten salt in the high-temperature molten salt tank 84. According to the present invention, a power generation system throughout the day can be realized by switching between power generation by the power generation unit during the daytime described above and power generation unit 81 at night.

In the electric power hydrogen co-production system 103, there is only one heat source 12 because there is no radiation source. Thermal radiation energy increases in proportion to the fourth power of the absolute temperature, so if the heat collecting part 12a becomes too high, the radiation heat loss increases _. By flowing and cooling, thermal energy is quickly transferred to supercritical CO ₂ , making it possible to achieve hydrogen production and power generation while also suppressing radiant heat loss.
(Mode of using geothermal heat)

FIG. 20 shows an electric power and hydrogen co-production system 104 according to a second embodiment of the present invention (an example that uses high-temperature geothermal energy). The power and hydrogen co-production system 104 achieves power generation and hydrogen production using heat in a high temperature range from the magma layer 12b located deep underground.
As shown in FIG. 20, the power-hydrogen co-production system 104 includes a CO ₂ pipe 2g as a supercritical CO ₂ decomposition unit , which is placed deep underground to receive sufficient heat from the magma layer 12b, and a supercritical Using a CO ₂ and CO circulation path 4g, 10g, a CO separation and recovery furnace 90 having a getter material that separates CO from the gas sent from the CO ₂ pipe 2g, and supercritical CO ₂ heated by heat exchange. A power generation device 60 (see FIG. 18) that generates electricity using water, a water gas shift reaction section 3g that uses water and a gas containing CO decomposed in the high temperature range of the magma layer 12b, and A power generation device 60 (see FIG. 18) that generates power using critical CO ₂ is provided.

According to the power-hydrogen co-production system 104, since supercritical CO2 _is used as a medium to transport heat from the magma layer 12b, the medium can be circulated deep underground much more efficiently than when water is used. It is possible to generate electricity and also to produce hydrogen.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above examples. For example, the fusion power reactor is not limited to the tokamak-type power reactor shown in FIG. 11, but can also be applied to other types of fusion power reactors equipped with blankets or diverters.

Further, in the above example, FLiNaK was used as the molten salt, but the present invention is not limited thereto, and other molten salts that have a sufficiently large heat capacity and can be used appropriately can be used. Moreover, metal aluminum can also be used as a solar heat storage material molten salt. Aluminum has a high thermal conductivity and is advantageous for heat transfer, and also melts at 660° C. and has a large heat of fusion and specific heat, so it is advantageous for heat storage (heat of fusion, sensible heat).

1, 1b Hydrogen production equipment 2-2g supercritical CO ₂ decomposition section (CO ₂ piping)
3-3g Water gas shift reaction section 4-4g First circulation path 5-5d Heat source 6-6d Radiation source 7-7d One source (heat source and radiation source), nuclear power reactor, fusion power reactor 8 First separation Part 9 Second separation part 10 to 10g Second circulation path 11 Supercriticalization mechanism 12, 12a, 12b Heat source (high temperature range), heat collection part for solar power generation, magma layer 13 Radiation source 14 One source ( heat source and radiation source in high temperature range)
20 Storage pipe containing high-level radioactive waste 21 Vitrified material 22 Facility for high-level radioactive waste 30 Core of nuclear power reactor 31 Molten salt circulation path 32 Pump with motor 33 Second piping 34 Shielding shield 35 Power generation device 36 Gas turbine section 40 Plasma vacuum vessel 41 Superconducting helical coil 42 Superconducting poloidal coil 43 Electromagnetic force support structure 44 Cryostat (insulated vacuum vessel)
45 Blanket 46 Diverter 47 Radiation/neutron multiplier 48 Supercritical CO ₂ inlet piping 49 Supercritical CO ₂ outlet piping 50 Core plasma 51 Diverter cassette 52 Cooling water piping for plasma vacuum vessel 40 53 Piping connection 55 Heat Exchanger 56 Inlet piping 57 Outlet piping 58 Inlet port 59 Outlet port 60 Power generation device using supercritical CO ₂ 61 Main heat exchanger 62 Low pressure compressor 63 High pressure compressor 64 Bypass compressor 65 Gas turbine 66 Generator 67a First regeneration heat Exchanger 67b Second regenerative heat exchanger 67c Precooler 68 Intercooler 69 Molten salt circulation path 70 to 70e Cooling piping (CO ₂ piping) that cools the diverter 46 or diverter cassette 51
71-71e Piping section 72-72e Surface plate 73 Supercritical CO ₂ flowing through the piping section
74a to 74e Inlet manifold 75a to 75e Outlet manifold 80 Tower 81 Power generation section 82 Piping for circulating molten salt heated from the heat collection section 83 Heliostat 84 High temperature molten salt tank 85 Low temperature molten salt tank 86 Heat exchanger 90 CO separation and recovery Furnace 100, 101, 102, 103, 104 Electricity hydrogen co-production system

Claims (23)

A hydrogen production device,
By heating supercritical CO ₂ to a temperature above the critical temperature under γ-ray irradiation , the CO/CO ₂ ratio becomes 10% or more compared to subcritical CO ₂ gas under γ-ray irradiation. a supercritical CO ₂ decomposition unit that causes a CO ₂ pyrolysis reaction to decompose the supercritical CO ₂ into CO and O ₂ so as to increase the
a water gas shift reaction section that generates _{H 2} and CO 2 by causing a water gas shift reaction between CO decomposed in the supercritical CO _{2 decomposition section and H 2 O} ;
A hydrogen production device equipped with. 2. The supercritical CO ₂ decomposition section comprises a CO ₂ pipe into which supercritical CO ₂ is introduced, arranged to receive heat from an external heat source and gamma rays from an external radiation source. The hydrogen production device described. The hydrogen production apparatus according to claim 2, further comprising a supercritical CO ₂ circulation path that returns the CO ₂ generated by the water gas shift reaction unit to the supercritical CO ₂ decomposition unit in a supercritical state. The hydrogen production apparatus according to claim 2 or 3, wherein the external heat source is a heat source with a temperature of 200°C to 800°C. A hydrogen production device,
a supercritical CO ₂ decomposition unit that causes a CO ₂ thermal decomposition reaction to decompose the supercritical CO ₂ into CO and O ₂ by heating the supercritical CO ₂ to a temperature of 1100° C. or higher;
a water gas shift reaction section that generates _{H 2} and CO 2 by causing a water gas shift reaction between CO decomposed in the supercritical CO _{2 decomposition section and H 2 O} ;
Equipped with
The supercritical CO ₂ decomposition unit includes a CO ₂ pipe into which supercritical CO ₂ is introduced, which is arranged to receive heat from an external heat source in a high temperature range of 1100° C. or higher,
In the hydrogen production device, the CO ₂ piping is cooled by a CO ₂ thermal decomposition reaction of the supercritical CO ₂ . The hydrogen production apparatus according to any one of claims 2 to 4, wherein the external heat source is a heater, and the external radiation source is ^{a 60} CO radiation source. The hydrogen production apparatus according to claim 5 , wherein the external heat source is a fusion power reactor. The hydrogen production apparatus according to claim 7 , wherein the CO ₂ pipe is configured as a pipe that cools a diverter of the fusion power reactor. The hydrogen production device according to claim 8 , wherein the diverter is comprised of a plurality of diverter cassettes. The diverter cassette includes a tungsten plate arranged to receive heat radiated from the core plasma of the fusion power reactor, and the CO ₂ pipe connected to the back side of the plate. 9. The hydrogen production device according to 9 . The hydrogen production apparatus according to claim 10 , wherein the CO ₂ pipe connected to the back side of the plate is composed of a plurality of pipes. The CO ₂ pipe is a heat exchanger that performs heat exchange between an inlet pipe for supercritical CO ₂ input to the diverter, an outlet pipe for gas output from the diverter, and the inlet pipe and the outlet pipe. The hydrogen production device according to any one of claims 8 to 11 , comprising: a container. The hydrogen production device according to claim 5, wherein the CO ₂ piping is arranged in a heat collection part where sunlight is collected. The hydrogen production device according to claim 5, wherein the CO ₂ pipe is arranged underground so as to receive heat from a magma layer. The hydrogen production apparatus according to any one of claims 1 to 14 , wherein the water gas shift reaction section includes magnetite (Fe ₃ O ₄ ) or ferric oxide (Fe ₂ O ₃ ) as a catalyst. The hydrogen production device according to any one of claims 7 to 12 ,
The fusion power reactor;
A power generation device that generates electricity by circulating supercritical CO ₂ heated by the fusion power reactor and rotating a gas turbine;
A power and hydrogen co-production system equipped with A power hydrogen co-production system comprising a hydrogen production device and a power generation device,
The hydrogen production device includes:
A CO 2 pipe into which supercritical CO ₂ is introduced is arranged to receive heat and radiation from a nuclear power reactor, and the supercritical CO ₂ in the _{CO 2 pipe} is converted into CO and O by the heat and radiation. a supercritical CO2 decomposition unit that causes a _CO2 pyrolysis reaction to decompose _CO2 into ₂ ;
a water gas shift reaction section that generates _{H 2} and CO 2 by causing a water gas shift reaction between CO decomposed in the supercritical CO _{2 decomposition section and H 2 O} ;
a supercritical CO 2 circulation path that returns the CO ₂ generated by the water gas shift reaction section to the supercritical CO ₂ decomposition section in a supercritical state _;
Equipped with
The nuclear power reactor includes a molten salt circulation path through which molten salt circulates for transferring heat generated in the core of the nuclear power reactor, and the CO ₂ pipe is disposed within the molten salt circulation path,
The power generation device is arranged in the supercritical CO ₂ circulation path, and generates electricity by rotating a gas turbine using the supercritical CO ₂ flowing through the supercritical CO ₂ circulation path. A power hydrogen co-production system comprising a hydrogen production device and a power generation device,
The hydrogen production device includes:
A CO 2 pipe into which supercritical CO ₂ is introduced is arranged to receive heat and radiation from a nuclear power reactor, and the supercritical CO ₂ in the _{CO 2 pipe} is converted into CO and O by the heat and radiation. a supercritical CO2 decomposition unit that causes a _CO2 pyrolysis reaction to decompose _CO2 into ₂ ;
a water gas shift reaction section that generates _{H 2} and CO 2 by causing a water gas shift reaction between CO decomposed in the supercritical CO _{2 decomposition section and H 2 O} ;
Equipped with
The nuclear power reactor includes a molten salt circulation path through which molten salt circulates for transferring heat generated in the core of the nuclear power reactor, and the CO ₂ pipe is disposed within the molten salt circulation path,
The power generation device generates electricity by rotating a gas turbine using CO, CO ₂ and O ₂ discharged from the CO ₂ pipe of the supercritical CO ₂ decomposition unit,
The water gas shift reaction section utilizes CO out of the CO, CO ₂ and O ₂ that rotated the gas turbine of the power generation device for the water gas shift reaction, and the CO ₂ generated by the water gas shift reaction is used for the water gas shift reaction. A power and hydrogen co-production system where _CO2 is returned to the pipe. The hydrogen production device according to claim 13 ,
a power generation device that generates electricity by rotating a gas turbine using supercritical CO ₂ heated by the heat of the heat collecting section;
A power and hydrogen co-production system equipped with The hydrogen production device according to claim 14 ,
A power generation device that generates electricity by rotating a gas turbine using supercritical CO ₂ heated by the heat of the magma layer;
A power and hydrogen co-production system equipped with A method of decomposing carbon dioxide, the method comprising:
A decomposition process in which supercritical _CO2 is heated to a temperature above the critical temperature under γ-ray irradiation to decompose supercritical _CO2 into CO and oxygen such that the CO/ _CO2 ratio is 10% or more. How to prepare. A method of decomposing carbon dioxide, the method comprising:
Under γ-ray irradiation, the CO ₂ is heated to a temperature of 25° C. or higher and pressurized to a pressure of 7.38 MPa or higher, thereby converting the CO ₂ into CO and oxygen so that the CO/CO ₂ ratio becomes 10% or higher. A method comprising a decomposition step of decomposing into. A method for producing hydrogen, the method comprising:
the decomposition step of the method according to claim 21 or 22 ;
A water gas shift step of adding water to the CO decomposed in the decomposition step to cause a water gas shift reaction to generate H ₂ and CO ₂ ;
A hydrogen production method comprising: