Hydrogen gas production system and hydrogen gas production method

Abstract

Provided are a hydrogen gas production system and a hydrogen gas production method, with which it is possible to produce a high-purity hydrogen gas at a low cost by recovering a high-purity hydrogen gas at a high recovery rate without using a large-scale device. A hydrogen gas production system 100 according to the present invention comprises: a degassing device 20 that degasses raw water; an electrolysis device 30 that generates a hydrogen gas by electrolyzing the raw water degassed by the degassing device 20; piping 62 that connects the degassing device 20 and the electrolysis device 30 and that partitions a flow path through which the raw water is fed from the degassing device 20 to the electrolysis device 30; and a first oxygen gas supply device 40 that supplies an oxygen gas as a degassing gas to the degassing device 20.

Description

Hydrogen gas production system and hydrogen gas production method

[0001] The present invention relates to a hydrogen gas production system and a hydrogen gas production method for producing hydrogen gas by electrolyzing water.

[0002] Conventionally, various methods have been used to produce hydrogen gas in various industrial fields such as the semiconductor-related field, including partial oxidation, steam reforming, and electrolysis. In particular, electrolysis often uses an electrolyzer that electrolyzes water to generate oxygen gas and hydrogen gas.

[0003] The hydrogen gas obtained by a typical electrolysis device contains impurities such as air components (oxygen gas, nitrogen gas, argon gas, carbon dioxide gas) dissolved in the raw water and moisture, and therefore requires purification after electrolysis to remove the impurities. Adsorption purification devices are often used to remove and purify impurity gases, and these devices require a regeneration process after a certain operating time. This regeneration process uses the generated hydrogen gas, resulting in a loss of the generated hydrogen gas. In particular, when producing deuterium gas, expensive gases must be used for regeneration, which increases production costs.

[0004] Therefore, the following technologies are known as technologies that can obtain high-purity hydrogen gas without performing purification after electrolysis. Patent Document 1 describes a method for producing hydrogen gas in which raw water to be subjected to electrolysis is flash-evaporated under reduced pressure in advance to remove air components from the raw water. Patent Document 2 describes a method for producing hydrogen gas in which raw water is degassed by contacting a portion of the hydrogen gas produced by electrolysis with the raw water, thereby removing air components from the raw water.

[0005] Japanese Patent Publication No. 3-2237 Japanese Patent Application Laid-Open No. 2006-206989

[0006] However, the method of Patent Document 1 requires a large-scale apparatus for flash evaporation under reduced pressure, which increases the production cost.Furthermore, the method of Patent Document 2 uses a portion of the produced hydrogen gas for degassing, but the degassed hydrogen gas contains air components that were contained in the raw water, so it must be discarded, which reduces the recovery rate of the produced hydrogen gas.

[0007] In view of the above problems, the present invention aims to provide a hydrogen gas production system and a hydrogen gas production method that are capable of producing high-purity hydrogen gas at low cost by recovering high-purity hydrogen gas at a high recovery rate without using large-scale equipment.

[0008] The inventors conducted extensive research to solve the above-mentioned problems and discovered the following. By degassing the raw water to be electrolyzed using oxygen gas, impurity gases (such as nitrogen gas, argon gas, and carbon dioxide gas) dissolved in the raw water can be removed, allowing for the production of high-purity hydrogen gas. Note that the oxygen gas dissolved in the raw water is converted into water during the electrolysis process and is not contained in the hydrogen gas. Degassing using oxygen gas as described above eliminates the need for a purification device and reduces the loss of hydrogen gas used in the regeneration of the purification device. Furthermore, the above method does not require large-scale pretreatment equipment such as a reduced-pressure flash evaporation device, allowing for the downsizing of equipment and reducing production costs. Furthermore, the present invention does not use the hydrogen gas produced during the degassing of the raw water, resulting in a high hydrogen gas recovery rate, which also contributes to reduced production costs.

[0009] That is, the gist and configuration of the present invention are as follows.

[0010] [1] A hydrogen gas production system comprising: a degassing device that degasses raw water; an electrolyzer that electrolyzes the raw water degassed by the degassing device to generate hydrogen gas; piping that connects the degassing device and the electrolyzer and defines a flow path through which the raw water is sent from the degassing device to the electrolyzer; and a first oxygen gas supplying device that supplies oxygen gas as a degassing gas to the degassing device.

[0011] [2] The hydrogen gas production system according to [1] above, wherein the electrolyzer has an electrolytic cell in which an anode chamber accommodating an anode and a cathode chamber accommodating a cathode are adjacent to each other via an ion exchange membrane, and further has a second oxygen gas supply device that supplies oxygen gas to the anode chamber.

[0012] [3] The hydrogen gas production system according to [1] or [2] above, wherein the raw water contains heavy water, and the hydrogen gas generated in the electrolysis device contains deuterium gas.

[0013] [4] A method for producing hydrogen gas, comprising: a degassing step of degassing raw water in a degassing device; a subsequent step of sending the raw water from the degassing device to an electrolyzer via a pipe; and an electrolysis step of electrolyzing the raw water degassed in the degassing step in the electrolyzer to generate hydrogen gas, wherein the raw water is degassed using oxygen gas in the degassing step.

[0014] [5] The method for producing hydrogen gas according to the above [4], wherein the electrolyzer has an electrolytic cell in which an anode chamber accommodating an anode and a cathode chamber accommodating a cathode are adjacent to each other via an ion exchange membrane, and in the electrolysis step, the anode chamber is purged with oxygen gas.

[0015] [6] The method for producing hydrogen gas according to the above [4] or [5], wherein the raw water contains heavy water, and the hydrogen gas generated in the electrolysis step contains deuterium gas.

[0016] According to the hydrogen gas production system and hydrogen gas production method of the present invention, high-purity hydrogen gas can be produced at low cost by recovering high-purity hydrogen gas at a high recovery rate without using large-scale equipment.

[0017] 1 is a schematic diagram showing the device configuration of a hydrogen gas production system according to an embodiment of the present invention; 2 is a schematic diagram showing an electrolysis cell according to an embodiment of the present invention;

[0018] Hereinafter, embodiments of a hydrogen gas production system and a hydrogen gas production method according to the present invention will be described. Note that the embodiment described below is an example of a specific embodiment of the present invention, and the configuration of the present invention is not limited to this specific example.

[0019] [Hydrogen Gas Production System and Hydrogen Gas Production Method] Figure 1 shows the device configuration of a hydrogen gas production system 100 according to one embodiment of the present invention. The hydrogen gas production system 100 includes a degassing device 20 that degasifies raw water, an electrolyzer 30 that electrolyzes the raw water degassed by the degassing device 20 to generate hydrogen gas, a pipe 62 that connects the degassing device 20 and the electrolyzer 30 and defines a flow path through which the raw water is sent from the degassing device 20 to the electrolyzer 30, and a first oxygen gas supply device 40 that supplies oxygen gas to the degassing device 20 as a degassing gas. The electrolyzer 30 also includes an outlet 70 for oxygen gas produced as a by-product of electrolysis and an outlet 72 for hydrogen gas produced by electrolysis. The hydrogen gas production system 100 may further include a raw water supply tank 10 that supplies raw water to the degassing device 20 and a second oxygen gas supply device 50 that supplies oxygen gas to the electrolyzer 30 as a degassing gas.

[0020] 1 , piping 60 connects the raw water supply tank 10 and the degassing device 20 and defines a flow path through which raw water is sent from the raw water supply tank 10 to the degassing device 20. piping 64 connects the degassing device 20 and the first oxygen gas supply device 40 and defines a flow path through which oxygen gas is sent from the first oxygen gas supply device 40 to the degassing device 20. piping 66 connects the electrolyzer 30 and the second oxygen gas supply device 50 and defines a flow path through which oxygen gas is sent from the second oxygen gas supply device 50 to the electrolyzer 30.

[0021] A hydrogen gas production method according to one embodiment of the present invention can be suitably implemented using a hydrogen gas production system 100, and includes a degassing step in which raw water is degassed in a degassing device 20, a subsequent step in which the raw water is sent from the degassing device 20 to an electrolyzer 30 via a pipe 62, and an electrolysis step in which the raw water degassed in the degassing step is electrolyzed in the electrolyzer 30 to generate hydrogen gas, and is characterized in that the raw water is degassed using oxygen gas in the degassing step.

[0022] (Raw water) There are no particular limitations on the raw water, and light water (H ２ O), half-heavy water (HDO), and heavy water (D ２For example, the raw water may be ordinary pure water (substantially H ２ Examples of usable raw water include deuterium-enriched water (water containing deuterium D at a higher ratio than ordinary pure water, i.e., water containing a higher content of at least one of semi-heavy water and heavy water than ordinary pure water). When deuterium-enriched water is used as raw water, it is preferable that the content of deuterium (D) relative to all hydrogen atoms in the raw water (deuterium-enriched water) is 90 [atom% D] or more, since this allows for the production of hydrogen gas in which D is sufficiently concentrated. There is no particular upper limit to the content of D relative to all hydrogen atoms in the raw water (deuterium-enriched water), but from an industrial perspective, the content of D relative to all hydrogen atoms in the raw water (deuterium-enriched water) is generally 99.98 [atom% D] or less. Furthermore, the raw water may contain a supporting salt such as potassium hydroxide or hypochlorite depending on the electrolysis apparatus used.

[0023] The content ratio of D to all hydrogen atoms in the raw water can be determined by subjecting the raw water to analysis using a nuclear magnetic resonance spectrometer (for example, manufactured by JEOL Ltd.), measuring the areas of H atoms and D atoms, and calculating the ratio of the area of ​​D atoms to the total area of ​​H atoms and D atoms.

[0024] (Raw water supply tank 10) The raw water supply tank 10 is a device that stores raw water and is connected to the degassing device 20 via piping 60. There are no particular restrictions on the material of the raw water supply tank 10, but if a material that is easily permeable to air components, such as resin, is used, moisture in the air may permeate and enter the raw water supply tank 10, potentially reducing the deuterium enrichment of the raw water. Therefore, it is preferable to use a stainless steel or glass material that is not permeable to air components.

[0025] (Piping 60) The hydrogen gas production system 100 has piping 60 that connects the raw water supply tank 10 and the degassing device 20 and defines a flow path through which raw water is sent from the raw water supply tank 10 to the degassing device 20. The material of the piping 60 is not particularly limited, but materials that are easily permeable to air components, such as resin, may impair the effectiveness of the oxygen gas purging, so it is preferable to use SUS or glass materials that are not permeable to air components.

[0026] (Degassing device 20) The degassing device 20 is a device capable of removing air components from raw water, and is connected to the raw water supply tank 10, the electrolyzer 30, and the first oxygen gas supply device 40 via pipes 60, 62, and 64, respectively. The degassing device 20 is not particularly limited other than satisfying the above requirements, and a degassing device based on the principles of bubbling degassing, vacuum degassing, ultrasonic degassing, or a combination of these can be used. Note that, in order to efficiently purge the degassing device 20 with oxygen gas, the degassing device 20 preferably has a sealed structure. Furthermore, since it is preferable to purge the atmospheric gas within the degassing device 20 with oxygen in addition to directly degassing the raw water contained in the degassing device 20, the degassing device 20 is preferably a vacuum degassing device (e.g., a rotary evaporator).

[0027] (First oxygen gas supply device 40) The first oxygen gas supply device 40 is connected to the degassing device 20 by piping 64 and supplies oxygen gas to the degassing device 20. The first oxygen gas supply device 40 may supply oxygen gas directly to the raw water in the degassing device 20, or may supply oxygen gas to the space in the degassing device 20 that comes into contact with the raw water (purging the space with oxygen), or may be capable of doing both. The first oxygen gas supply device 40 is not particularly limited as long as it is a device that can supply oxygen gas, and a conventionally known device can be used.

[0028] In the present invention, "oxygen gas" means a gas consisting of oxygen, although it is of course acceptable for oxygen gas to contain impurity gases that are unavoidable in industry.

[0029] (Piping 64) The hydrogen gas production system 100 has piping 64 that connects the degassing device 20 and the first oxygen gas supplying device 40 and defines a flow path through which oxygen gas is sent from the first oxygen gas supplying device 40 to the degassing device 20. The material of the piping 64 is not particularly limited, but materials that are easily permeable to air components, such as resin, may impair the effect of oxygen gas purging, so it is preferable to use SUS or glass materials that are not permeable to air components.

[0030] (Degassing process) The degassing process is a process in which raw water is degassed using oxygen gas in the degassing device 20. In the degassing process, it is preferable to supply oxygen gas to the degassing device 20 using the first oxygen gas supply device 40. Furthermore, in the degassing process, it is preferable to purge the inside of the degassing device 20 with oxygen gas before supplying raw water to the degassing device 20. Note that the purged or supplied oxygen gas will be dissolved in the raw water, but will not be included in the produced hydrogen gas because it is converted to water in the subsequent electrolysis process.

[0031] The method of supplying oxygen gas from the first oxygen gas supply device 40 to the degassing device 20 in the degassing step may be to supply oxygen gas directly to the raw water in the degassing device 20, or to supply oxygen gas to the space in the degassing device 20 that comes into contact with the raw water (purging the space with oxygen), or both. The flow rate of the oxygen gas supplied during the degassing step is not particularly limited, but may be about 10 L / min.

[0032] The conditions for the degassing step are preferably adjusted to appropriate conditions taking into account the vapor pressure of water. Specifically, when a reduced-pressure degassing device such as a rotary evaporator is used as the degassing device 20, the amount of gas dissolved in water increases in proportion to the partial pressure and decreases in proportion to the temperature. Therefore, from the viewpoint of obtaining an appropriate amount of gas dissolved in water, the pressure inside the degassing device 20 in the degassing step is preferably 100 hPa or less. On the other hand, if the pressure inside the degassing device 20 in the degassing step is less than 5 hPa, the steam cannot be completely trapped, leading to water loss, so the pressure inside the degassing device 20 in the degassing step is preferably 5 hPa or more. Furthermore, from the viewpoint of obtaining an appropriate amount of gas dissolved in water, the temperature of the internal space of the degassing device 20 in the degassing step is preferably 20°C or higher. On the other hand, if the temperature of the internal space of the degassing device 20 in the degassing step exceeds 90°C, excessive energy is required for heating, so the temperature of the internal space of the degassing device 20 in the degassing step is preferably 90°C or lower.

[0033] In the degassing process, the raw water is degassed using oxygen gas, which removes impurity gases (nitrogen gas, argon gas, carbon dioxide gas, etc.) dissolved in the raw water, allowing high-purity hydrogen gas to be produced in the subsequent electrolysis process. This eliminates the need for a purification device and reduces the loss of hydrogen gas used in regenerating the purification device. Furthermore, the above method does not require large-scale pretreatment equipment such as a reduced-pressure flash evaporation device, making it possible to downsize the equipment and keep production costs low. In addition, because the produced hydrogen gas is not used when degassing the raw water, the recovery rate of hydrogen gas is high, which also contributes to reducing production costs.

[0034] (Piping 62) The hydrogen gas production system 100 has piping 62 that connects the degassing device 20 and the electrolyzer 30 and defines a flow path through which raw water is sent from the degassing device 20 to the electrolyzer 30. The material of the piping 62 is not particularly limited, but materials that are easily permeable to air components, such as resin, may impair the effect of oxygen gas purging, so it is preferable to use SUS or glass materials that are not permeable to air components.

[0035] (Liquid Delivery Process) After the degassing process, the raw water is delivered from the degassing device 20 to the electrolyzer 30 through the pipe 62. The delivery is performed while restoring the pressure inside the degassing device 20, and oxygen gas supplied from the first oxygen gas supply device 40 can be used as the gas for restoring the pressure. Furthermore, by purging the inside of the electrolyzer 30 with oxygen gas using the second oxygen gas supply device 50 described below before the delivery, it is possible to prevent the incorporation of impurities.

[0036] (Electrolyzer 30) The electrolyzer 30 is a device that electrolyzes raw water to generate hydrogen gas, and is connected to the degassing device 20 by a pipe 62 through which the raw water is delivered, and has an outlet 70 for oxygen gas that is a by-product of electrolysis, and an outlet 72 for hydrogen gas that is generated by electrolysis. The electrolyzer 30 is not particularly limited as long as it satisfies the above requirements, but it preferably has an electrolytic cell 32 as shown in Fig. 2. Furthermore, the electrolyzer 30 is preferably connected to a second oxygen gas supply device 50 via a pipe 66.

[0037] 2 is a schematic diagram of an electrolytic cell 32 according to one embodiment of the present invention. The electrolytic cell 32 has a structure in which an anode chamber 34 containing an anode and a cathode chamber 36 containing a cathode are adjacent to each other with an ion exchange membrane 38 interposed therebetween. The ion exchange membrane 38 is a membrane that converts hydrogen ions (H ＋ ) selectively permeates the ion exchange membrane 38. ＋ The ion exchange membrane 38 is not particularly limited as long as it has the above function.

[0038] (Second oxygen gas supply device 50) The second oxygen gas supply device 50 is connected to the electrolyzer 30 by a pipe 66 and supplies oxygen gas to the electrolyzer 30. The second oxygen gas supply device 50 may supply oxygen gas directly to the raw water in the electrolyzer 30, or may supply oxygen gas to a space in the electrolyzer 30 that contacts the raw water (purging the space with oxygen), or may be capable of both. When the electrolyzer 30 has an electrolytic cell 32, the second oxygen gas supply device 50 preferably supplies oxygen gas to the anode chamber 34 of the electrolytic cell 32. The second oxygen gas supply device 50 is not particularly limited as long as it is a device that can supply oxygen gas, and a conventionally known device can be used.

[0039] (Piping 66) The hydrogen gas production system 100 preferably has piping 66 that connects the electrolyzer 30 and the second oxygen gas supply device 50 and defines a flow path through which oxygen gas is sent from the second oxygen gas supply device 50 to the electrolyzer 30. The material of the piping 66 is not particularly limited, but materials that are easily permeable to air components, such as resin, may impair the effect of oxygen gas purging, so it is preferable to use SUS or glass materials that are not permeable to air components.

[0040] (Electrolysis Step) The electrolysis step is a step in which the raw water degassed in the degassing step is electrolyzed in the electrolyzer 30 to generate hydrogen gas. When the electrolyzer 30 used in the electrolysis step has an electrolytic cell 32, it is preferable to supply oxygen gas from the second oxygen gas supply device 50 to the anode chamber 34 of the electrolytic cell 32. The oxygen gas may be supplied directly to the raw water in the anode chamber 34, or may be supplied to the space in the anode chamber 34 that contacts the raw water (purging the space with oxygen gas), or both may be performed.

[0041] In the electrolysis step, when oxygen gas is purged from the second oxygen gas supply device 50 into the anode chamber 34, it is preferable to maintain a pressurized state of about atmospheric pressure or more and 100 kPaG or less. By performing electrolysis under a pressurized state, it is possible to reduce the intrusion of air components other than oxygen gas into the electrolyzer 30 due to the pressure difference. Because the purged oxygen gas is removed during the electrolysis process, purging oxygen gas into the anode chamber 34 makes it possible to obtain hydrogen gas with fewer impurities.

[0042] The hydrogen gas obtained by the electrolysis process may contain moisture as an impurity. By treating the hydrogen gas obtained by the electrolysis process with an appropriate moisture removal device, high-purity hydrogen gas from which moisture has been removed can be obtained.

[0043] In the electrolysis process, in the anode chamber 34 of the electrolysis cell 32, raw water is decomposed into oxygen gas and hydrogen ions by the reaction shown in the following formula (1). The generated hydrogen ions permeate the ion exchange membrane 38 and move to the cathode chamber 36, where they become hydrogen gas by the reduction reaction shown in the following formula (2). Most of the oxygen gas does not permeate the ion exchange membrane 38, but even the very small amount of oxygen gas that does permeate reacts with the hydrogen ions under the reducing conditions of the cathode to become water, and is therefore not included in the hydrogen gas generated at the cathode. H ２ O → 1 / 2O ２ +2H ＋ +2e － ... (1) 2H ＋ +2e － →H ２ ... (2)

[0044] In addition, the raw water is heavy water (D ２ When heavy water contains hydrogen, the hydrogen gas obtained by electrolysis of heavy water is deuterium gas (D ２ ). Furthermore, when the raw water contains semi-heavy water (HDO), the hydrogen gas obtained by electrolysis of the semi-heavy water is semi-deuterium gas (HD). When the raw water is deuterium-enriched water, the obtained hydrogen gas is also deuterium-enriched hydrogen gas (hydrogen gas with a higher proportion of deuterium D than ordinary hydrogen gas). Since the raw material cost of heavy water is higher than that of ordinary pure water, if the produced hydrogen gas is used as a purge gas for a degassing device, as in Patent Document 2, a portion of the produced hydrogen gas will be discarded, which will particularly increase the production cost. In contrast, in the present invention, by using oxygen gas as a purge gas, high-purity hydrogen gas can be produced without reducing the recovery rate of the produced hydrogen gas.

[0045] (Hydrogen Gas) High-purity hydrogen gas can be obtained by the above-described hydrogen gas production system and hydrogen gas production method. The gas obtained by this embodiment has a composition in which hydrogen gas accounts for 99.999 vol% or more in volume fraction. There is no upper limit to the volume fraction of hydrogen gas in the gas obtained by the present invention, but the volume fraction of hydrogen gas is typically 99.999999 vol% or less. Note that the gas obtained by the present invention may contain air components (one or more of argon gas, nitrogen gas, oxygen gas, and carbon dioxide gas) and moisture as impurities, but the air component is significantly reduced. By further treating the obtained hydrogen gas with an appropriate moisture removal device, high-purity hydrogen gas from which moisture has also been removed can be obtained.

[0046] The volume fractions of hydrogen gas and impurities in the gas obtained by the present invention can be calculated by analyzing the obtained gas using a gas chromatograph analyzer (e.g., manufactured by Shimadzu Corporation) and comparing the peak area values ​​with those of a standard gas.

[0047] Furthermore, by using deuterium-enriched water as raw water, hydrogen gas enriched in D can be obtained. When the content ratio of deuterium (D) to all hydrogen atoms in the hydrogen gas obtained by the present invention is 90 [atom% D] or more, improved performance (e.g., improved yield) compared to hydrogen (H) is generally expected when used in industrial applications. Therefore, the content ratio of deuterium (D) to all hydrogen atoms in the obtained hydrogen gas is preferably 90 [atom% D] or more. Meanwhile, although there is no particular upper limit for the content ratio of deuterium (D) to all hydrogen atoms in the obtained hydrogen gas, from an industrial viewpoint, the content ratio of D to all hydrogen atoms in the obtained hydrogen gas is generally 99.99 [atom% D] or less. The content ratio of deuterium (D) to all hydrogen atoms in the hydrogen gas can be determined in the same manner as for raw water.

[0048] For steps and conditions not described in the present invention, conventional methods can be used.

[0049] [Example 1] Using the apparatus shown in Figure 1, raw water (5 L of pure water) was degassed by purging with oxygen gas (10 L / min) under a reduced pressure of 20 hPa and at 35 °C for 1 hour. The degassed raw water was then sent to an electrolyzer, and electrolysis was performed under pressure (10 kPaG) by purging oxygen into the anode chamber. The hydrogen gas obtained by electrolysis was analyzed using a gas chromatograph analyzer (manufactured by Shimadzu Corporation) using the method described above. Table 1 shows the composition analysis results of the gas obtained in each example.

[0050] Example 2 Hydrogen gas was generated in the same manner as in Example 1, except that in the electrolysis step, the anode chamber of the electrolysis cell was neither purged with oxygen nor pressurized.

[0051] Example 3 Hydrogen gas was generated in the same manner as in Example 1, except that the raw water was changed from pure water to deuterium-enriched water (the abundance ratio of D was 99.9 atom % D).

[0052] Comparative Example 1 Hydrogen gas was generated in the same manner as in Example 1, except that oxygen gas purging in the degassing step was not performed.

[0053] Comparative Example 2 Hydrogen gas was generated in the same manner as in Example 1, except that the purge gas in the degassing step was changed to air.

[0054] In the examples where purging with oxygen gas was performed in the degassing step, high-purity hydrogen gas with a volume fraction of hydrogen gas of 99.999 vol% or more was obtained. On the other hand, in the comparative examples where purging with oxygen gas was not performed in the degassing step, the gas obtained had a lower volume fraction of hydrogen gas than the examples.

[0055]

[0056] REFERENCE SIGNS LIST 100 Hydrogen gas production system 10 Raw water supply tank 20 Degassing device 30 Electrolyzer 32 Electrolysis cell 34 Anode chamber 36 Cathode chamber 38 Ion exchange membrane 40 First oxygen gas supply device 50 Second oxygen gas supply device 60 Pipe 62 Pipe 64 Pipe 66 Pipe 70 Oxygen gas outlet 72 Hydrogen gas outlet

Claims

1. A hydrogen gas production system comprising: a degassing device that degasses raw water; an electrolysis device that electrolyzes the raw water degassed by the degassing device to generate hydrogen gas; piping that connects the degassing device and the electrolysis device and defines a flow path through which the raw water is sent from the degassing device to the electrolysis device; and a first oxygen gas supplying device that supplies oxygen gas as a degassing gas to the degassing device.

2. The hydrogen gas production system according to claim 1, wherein the electrolysis device has an electrolysis cell in which an anode chamber containing an anode and a cathode chamber containing a cathode are adjacent to each other via an ion exchange membrane, and further has a second oxygen gas supply device that supplies oxygen gas to the anode chamber.

3. The hydrogen gas production system according to claim 1 or 2, wherein the raw water contains heavy water, and the hydrogen gas generated in the electrolysis device contains deuterium gas.

4. A method for producing hydrogen gas, comprising: a degassing step of degassing raw water in a degassing device; a subsequent step of transporting the raw water from the degassing device to an electrolysis device via a pipe; and an electrolysis step of electrolyzing the raw water degassed in the degassing step in the electrolysis device to generate hydrogen gas, wherein the raw water is degassed using oxygen gas in the degassing step.

5. The method for producing hydrogen gas according to claim 4, wherein the electrolysis device has an electrolysis cell in which an anode chamber containing an anode and a cathode chamber containing a cathode are adjacent to each other via an ion exchange membrane, and in the electrolysis step, the anode chamber is purged with oxygen gas.

6. The method for producing hydrogen gas according to claim 4 or 5, wherein the raw water contains heavy water, and the hydrogen gas generated in the electrolysis step contains deuterium gas.

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