Helium gas production method

Abstract

This invention provides a method for producing helium gas that can be manufactured using heavy water. [Solution] The helium gas production method comprises an anode chamber 2, a cathode chamber 3, and an intermediate chamber 4 located between the anode chamber 2 and the cathode chamber 3 and filled with an ion exchange resin 4C. A first cation exchange membrane 5, a second cation exchange membrane 5A, and a positive electrode 6 are provided between the anode chamber 2 and the intermediate chamber 4, and a third cation exchange membrane 7 and a negative electrode 8 are provided between the cathode chamber 3 and the intermediate chamber 4. The second cation exchange membrane 5A is a membrane that selectively allows hydrogen ions to pass through. An electrolytic device 1 is arranged with the first cation exchange membrane 5 and the second cation exchange membrane 5A in that order from the anode chamber 2 side toward the intermediate chamber 4. Heavy water is introduced into the anode chamber 2 or the intermediate chamber 4, and electrolysis is performed to generate helium gas in the intermediate chamber 4.

Description

[Technical Field]

[0001] This invention relates to a method for producing helium gas. [Background technology]

[0002] Heavy water has different physical properties, such as electrical conductivity and degree of ionization, than ordinary water (light water), and it is known that ingesting large amounts of heavy water can disrupt biological reactions. Therefore, there is a need for equipment and methods that can separate heavy water from treated water containing it as safely as possible.

[0003] Helium gas contains, 3 He and 4 He exists, especially 4 Helium is used in a variety of applications, such as semiconductor manufacturing and cooling of superconducting magnets. Helium gas is generally produced by separating and purifying natural gas, and therefore its production depends on the amount of natural gas available. Consequently, the amount of helium gas that can be produced is limited. Methods for producing helium gas from sources other than natural gas have been disclosed (for example, Patent Document 1).

[0004] The helium production method described in Patent Document 1 is a method for producing helium using an electrolysis apparatus equipped with a first electrode, a second electrode, and a pulse supply unit that applies a pulse voltage between the first electrode and the second electrode. In this helium production method, the first electrode and the second electrode are immersed in raw material water containing tritium water or heavy water, and helium is generated in the raw material water by applying a positive voltage pulse to the first electrode, and immediately after applying a negative voltage pulse accompanied by a negative pulse current to the first electrode. The pulse supply unit has a pulse power supply and a diode, and it is preferable that the pulse half-width of the positive voltage pulse and the negative voltage pulse applied to the first electrode are 50 to 1000 ns, the peak voltage of the positive voltage pulse applied to the first electrode is 5 to 50 kV, and the peak voltage of the negative voltage pulse applied to the first electrode is -5 to -50 kV. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2024-65378 [Overview of the project] [Problems that the invention aims to solve]

[0006] The helium production method described in Patent Document 1 requires a pulse supply source and other components, necessitating a large amount of energy. If a helium gas production method can be established that does not require large amounts of energy and is simple to use, it would be possible to supply helium gas more cheaply and in a shorter time. Furthermore, if a method for producing helium gas from treated water containing heavy water can be established, it would have significant industrial implications.

[0007] The present invention aims to provide a method for producing helium gas that can be manufactured using heavy water. [Means for solving the problem]

[0008] The helium gas production method according to the present invention comprises an anode chamber having a first opening and a second opening, a cathode chamber having a third opening and a fourth opening, and an intermediate chamber having a fifth opening and a sixth opening, and positioned between the anode chamber and the cathode chamber, with an ion exchange resin filling the interior. A first cation exchange membrane, a second cation exchange membrane, and a positive electrode are provided between the anode chamber and the intermediate chamber, and a third cation exchange membrane and a negative electrode are provided between the cathode chamber and the intermediate chamber, respectively. The second cation exchange membrane is a membrane that selectively allows hydrogen ions to pass through. The electrolytic device is arranged with the first cation exchange membrane and the second cation exchange membrane in that order from the anode chamber side toward the intermediate chamber, and heavy water is introduced into the anode chamber or the intermediate chamber, and electrolysis is performed to generate helium in the intermediate chamber.

[0009] The helium gas production method according to the present invention is characterized by circulating the migrated water, which has moved from the intermediate chamber to the cathode chamber, back into the intermediate chamber.

[0010] The helium gas production method according to the present invention is characterized by circulating the migratory water that has moved from the intermediate chamber to the cathode chamber back to the anode chamber. [Effects of the Invention]

[0011] The helium gas production method according to the present invention uses an electrolytic apparatus comprising an anode chamber, a cathode chamber, and an intermediate chamber located between the anode chamber and the cathode chamber and filled with an ion exchange resin. A first cation exchange membrane, a second cation exchange membrane, and a positive electrode are provided between the anode chamber and the intermediate chamber, and a third cation exchange membrane and a negative electrode are provided between the cathode chamber and the intermediate chamber. The second cation exchange membrane is a membrane that selectively permeates hydrogen ions, and the first cation exchange membrane and the second cation exchange membrane are arranged in that order from the anode chamber side toward the intermediate chamber. In this helium production method, heavy water is introduced into the anode chamber or the intermediate chamber, and helium gas is generated in the intermediate chamber by electrolysis. Because this helium production method can produce helium gas using heavy water and electrolysis, it does not require a large amount of energy and can produce helium gas in a simple manner. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of an electrolytic apparatus (electrolytic treatment system) used in a helium gas production method according to an embodiment of the present invention. [Modes for carrying out the invention]

[0013] In the helium gas production method according to this embodiment, the electrolytic apparatus 1 shown in Figure 1 is used. First, the electrolytic apparatus 1 will be described.

[0014] The electrolytic apparatus 1 is a three-chamber type electrolytic apparatus comprising an anode chamber 2, a cathode chamber 3 positioned opposite the anode chamber 2, and an intermediate chamber 4 positioned between the anode chamber 2 and the cathode chamber 3. Between the anode chamber 2 and the intermediate chamber 4, a positive electrode 6, a strongly acidic first cation exchange membrane (first cation exchange membrane) 5, and a hydrogen ion selective permeable membrane (second cation exchange membrane) 5A are arranged from the anode chamber 2 side toward the intermediate chamber 4. The hydrogen ion selective permeable membrane 5A is a membrane that selectively allows hydrogen ions to pass through, and this hydrogen ion selective permeable membrane 5A is provided superimposed on the strongly acidic first cation exchange membrane 5 and positioned in contact with the strongly acidic first cation exchange membrane 5. On the other hand, between the cathode chamber 3 and the intermediate chamber 4, a negative electrode 8 and a strongly acidic second cation exchange membrane (third cation exchange membrane) 7 are provided in order from the cathode chamber 3 side. Multiple magnets 9 are provided on the outside of the anode chamber 2, and multiple magnets 10 are provided on the outside of the cathode chamber 3. For example, annular neodymium magnets can be used for these magnets 10. The inside of the intermediate chamber 4 is filled with ion exchange resin. [Anode Chamber 2] The anode chamber 2 has an inlet (first opening) 2A and an outlet (second opening) 2B formed on the side opposite to the inlet 2A. As shown in Figure 1, the inlet 2A is connected to the tank 20 via a flow path 21, and the outlet 2B is connected to the tank 20 via a flow path 22. The liquid flowing out of the anode chamber 2 flows through the flow path 22 into the tank 20, and then flows through the flow path 21 and flows back into the anode chamber 2. A flow rate control device (not shown) is provided in the flow path 21, and this flow rate control device adjusts the flow rate of the liquid supplied from the tank 20 to the anode chamber 2. Heavy water, pure water, or tap water is used as the liquid flowing into the anode chamber 2. [Cathode Chamber 3] The cathode chamber 3 has an outlet (third opening) 3A and an outlet (fourth opening) 3B formed on the side opposite to outlet 3A. Outlet 3B is connected to tank 40 or tank 20 via flow path 32. When the moving water that has moved to cathode chamber 3 is to be circulated to the intermediate chamber 4, it is circulated via flow path 32A, and when the moving water that has moved to cathode chamber 3 is to be circulated to the anode chamber, it is circulated via flow path 32B. In addition, hydrogen generated in cathode chamber 3 is discharged to the outside of cathode chamber 3 through outlet 3A. [Intermediate Room 4] The intermediate chamber 4 has an inlet (fifth opening) 4A and an outlet (sixth opening) 4B formed on the side opposite to the inlet 4A. As shown in Figure 1, the inlet 4A is connected to the tank 40 via a flow path 41, and the outlet 4B is connected to the tank 40 via a flow path 42. The treated water electrolyzed in the intermediate chamber 4 flows through the flow path 42 into the tank 40, and then flows through the flow path 41 back into the intermediate chamber 4. A flow rate control device (not shown) is provided in the flow path 41, and this flow rate control device adjusts the flow rate of the liquid (heavy water or water) supplied from the tank 40 to the intermediate chamber 4.

[0015] The intermediate chamber 4 is filled with a cation exchange resin 4C. For example, a gel-type (gel-type structured ion exchange resin) or a macroporous-type (macroporous structured ion exchange resin) can be used for this cation exchange resin 4C. The liquid (heavy water or water) that flows into the intermediate chamber 4 passes through this cation exchange resin 4C and flows out from the outlet 4B. The tank 40 is held in the bathtub, and the temperature of the treated water inside the tank 40 is maintained at a constant temperature. The temperature of the liquid (heavy water or water) that flows from the tank 40 into the intermediate chamber 4 is preferably between 1 and 5 degrees Celsius.

[0016] The inlet 4A of the intermediate chamber 4 is connected to a cylinder 43A via a flow path 44, and a pump 43 is connected to the flow path 44. Nitrogen is fed into the flow path 44 by this pump 43. For example, a peristaltic pump can be used for this pump 43, and nitrogen flows into the inlet 4A of the intermediate chamber 4 via the flow path 44. When nitrogen is not allowed to flow into the intermediate chamber 4, the pump 43 is not operated. On the other hand, a flow path 45 is connected to the treatment tank 40, and a gas collector 46 and a pump 47 are provided in the flow path 45.

[0017] Between the anode chamber 2 and the intermediate chamber 4, from the anode chamber 2 side, a positive electrode 6, a strongly acidic first cation exchange membrane 5, and a hydrogen ion selective permeable membrane 5A are provided so as to partition the anode chamber 2 and the intermediate chamber 4. On the other hand, between the cathode chamber 3 and the intermediate chamber 4, from the intermediate chamber 4 side, a strongly acidic second cation exchange membrane 7 and a negative electrode 8 are provided so as to partition the cathode chamber 3 and the intermediate chamber 4. The positive electrode 6 and the negative electrode 8 are each connected to a constant current power source 50.

[0018] The electrolysis method using the electrolysis apparatus 1 according to the present embodiment is to allow heavy water or water to flow into the anode chamber 2 from the inlet 2A, discharge it from the outlet 2B, allow the liquid (heavy water or water) to flow into the intermediate chamber 4 from the inlet 4A, pass through the cation exchange resin 4C, and then discharge it from the outlet 4B. The moving water that has moved from the intermediate chamber 4 to the cathode chamber 3 returns to the tank 40 via the flow path 32A or to the tank 20 via the flow path 32B, and is circulated again to the intermediate chamber 4 or the anode chamber 2.

[0019] The helium gas production method according to the present embodiment is to allow heavy water to flow into the anode chamber 2 or the intermediate chamber 4 by the above electrolysis apparatus 1 and perform electrolysis. While performing electrolysis, by operating the pump 47, the gas generated in the intermediate chamber 4 is allowed to flow into the flow path 45 and collected by the gas collector 46. [Example 1] Using the electrolytic treatment system 100 (electrolyzer 1) shown in Figure 1, which targeted treated water containing heavy water, water was introduced into the anode chamber 2 from the inlet 2A and discharged from the outlet 2B. The treated water containing heavy water was introduced into the intermediate chamber 4 from the inlet 4A, passed through the cation exchange resin 4C, and then discharged from the outlet 4B. The water that moved from the intermediate chamber 4 to the cathode chamber 3 was returned to the tank 40 via the flow path 32A and circulated back to the intermediate chamber 4. In this embodiment, electrolysis was performed in the intermediate chamber 4 with and without introducing nitrogen via the flow path 44. The current value of the constant current power supply 50 was set to 16A or 20A, and electrolysis was performed for a certain period of time. The gas generated in the intermediate chamber 4 was collected by the gas collector 46. The experiment was conducted using treated water with an initial heavy water concentration of 2000 ppm to 5000 ppm and a pH of 3.0 to 7.0. Two types of cation exchange resin 4C, gel type and macroporous type, were used to fill the interior of the intermediate chamber 4. Pure water was introduced into the anode chamber 2 at a flow rate of 0.1 L / min to 1.0 L / min, and treated water containing heavy water of degree 1 to 5 was introduced into the intermediate chamber 4 at a flow rate of 0.01 L / min to 0.5 L / min. Strongly acidic (Na type) (CMB, manufactured by Astom Co., Ltd.) was used for the strongly acidic first cation exchange membrane 5 and the strongly acidic second cation exchange membrane 7, and HSFN (manufactured by AC Engineering Co., Ltd.) was used for the hydrogen ion selective permeable membrane 5A.

[0020] In the gas collected by the gas collector 3 He and 4 Table 1 shows the results of calculating the He concentration ratio (hereinafter also referred to as the He concentration ratio).

[0021] [Table 1]

[0022] The ratio of He concentration in the air is 1.37 × 10⁻⁶. -6 It is known that the He concentration ratio obtained in collector 46 ranges from 1.51 to 1.54 × 10⁻⁶. -6This was clearly different from the He concentration ratio in the air. By using the electrolysis device 1, it was found that He was generated in the intermediate chamber 4. [Example 2] Similar to Example 1, the treated water containing heavy water was targeted. The treated water containing heavy water was made to flow into the anode chamber 2 from the inlet 2A and discharged from the outlet 2B. Water was made to flow into the intermediate chamber 4 from the inlet 4A, passed through the cation exchange resin 4C, and then discharged from the outlet 4B. Also, the moving water that moved from the intermediate chamber 4 to the cathode chamber 3 was returned to the tank 20 and circulated again into the anode chamber 2. Other conditions were the same as those in Example 1. [Example 3] The treated water containing heavy water was made to flow into the anode chamber 2 from the inlet 2A and into the intermediate chamber 4 from the inlet 4A. The treated water that flowed into the anode chamber 2 was discharged from the outlet 2B. Also, the treated water that flowed into the intermediate chamber 4 passed through the cation exchange resin 4C and was then discharged from the outlet 4B. Other conditions were the same as those in Example 1.

[0023] Even under the conditions of Example 2 and Example 3, it was found that the gas collected by the gas collector 46 contained helium gas ( 3 He and 4 He).

[0024] Next, the operation and effects of the helium gas generation method according to this embodiment will be described.

[0025] The helium gas generation method according to this embodiment can generate helium gas in the intermediate chamber 4 by performing electrolysis using the above electrolysis device 1. Since the electric power used in electrolysis is small, helium gas can be obtained at low cost.

[0026] The helium gas generation method according to this embodiment can generate helium gas by performing electrolysis in the electrolysis device 1 without flowing nitrogen or inflowing gas into the intermediate chamber 4.

[0027] Although this embodiment has been described above, it is possible to select or replace the configurations listed in the above embodiment, or to change them to other configurations as appropriate, as long as they do not depart from the spirit of the present invention. In this embodiment, the target of electrolysis was described as treated water containing heavy water, but since the electrolytic apparatus and electrolytic method according to this embodiment were applicable to treated water containing heavy water, which is an isotope of light water (H2O), and were able to separate the heavy water, they can also be applied to treated water containing tritiated water, which is an isotope of light water, and similar effects can be obtained. [Explanation of symbols]

[0028] 1 Electrolyzer 2 Anode Chambers 2A Inlet (first opening) 2B Outlet (second opening) 3 Cathode Chamber 3A Outlet (third opening) 3B Outlet (fourth opening) 4. Intermediate Room 4A Inlet (fifth opening) 4B Outlet (sixth opening) 4C cation exchange resin 5. Strongly acidic primary cation exchange membrane (primary cation exchange membrane) 5A Hydrogen ion selective permeable membrane (second cation exchange membrane) 6. Positive electrode 7. Strongly acidic second cation exchange membrane (third cation exchange membrane) 8 negative electrode 20 tanks 21,22,32,41,42,44,45 Channel 32A, 32B channel 40 tanks 43,47 Pumps 43A cylinder 46 Gas collector 50 constant current power supply 100 Electrolytic Treatment Systems

Claims

1. an anode chamber having a first opening and a second opening, A cathode chamber having a third opening and a fourth opening, It has a fifth opening and a sixth opening, and comprises an intermediate chamber located between the anode chamber and the cathode chamber, with an ion exchange resin filling the interior. An electrolytic apparatus is provided in which a first cation exchange membrane, a second cation exchange membrane, and a positive electrode are provided between the anode chamber and the intermediate chamber, and a third cation exchange membrane and a negative electrode are provided between the cathode chamber and the intermediate chamber, the second cation exchange membrane is a membrane that selectively allows hydrogen ions to pass through, and the first cation exchange membrane and the second cation exchange membrane are arranged in that order from the anode chamber side toward the intermediate chamber, By introducing heavy water into the anode chamber or the intermediate chamber and performing electrolysis, helium is generated in the intermediate chamber. A method for producing helium gas characterized by the following features.

2. The moving water that has moved from the intermediate chamber to the cathode chamber is circulated back into the intermediate chamber. The helium gas production method according to feature 1.

3. The moving water that has moved from the intermediate chamber to the cathode chamber is circulated to the anode chamber. The helium gas production method according to feature 1.

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