Deuterium recycling method and deuterium recycling apparatus

Abstract

To provide a deuterium recycling method and recycling apparatus that can recover and recycle deuterium (D2) contained in exhaust gases emitted from processes utilizing deuterium. [Solution] A method for recycling deuterium, comprising: a recovery step of recovering exhaust gas containing light hydrogen (H2) and deuterium, which is discharged from a process utilizing deuterium (D2), by contacting it with an adsorbent capable of adsorbing them; and a desorption step of desorbing light hydrogen and deuterium from the adsorbent. The desorption step includes a light hydrogen separation step carried out under a first condition in which light hydrogen is preferentially desorbed from the adsorbent, and a deuterium separation step carried out under a second condition in which deuterium is preferentially desorbed from the adsorbent. The method for recycling deuterium according to this disclosure includes a step of supplying the gas containing deuterium obtained in the deuterium separation step as a raw material gas in the process.

Description

Technical Field

[0001] The present disclosure relates to a method for recycling deuterium and a deuterium recycling apparatus.

Background Art

[0002] Deuterium gas (D2) or heavy water (D2O) may be used in the production of semiconductors and chemicals. Deuterium gas (D2) and heavy water (D2O) are rare and expensive materials, and it has been considered to recover and reuse the deuterium-containing components discharged from the production process. For example, Patent Document 1 describes a heavy water recovery method including a heavy water generation step of generating heavy water in the exhaust gas containing deuterium gas generated in the semiconductor production process. The method described in Patent Document 1 is a method of recovering deuterium gas (D2) from the exhaust gas by synthesizing heavy water (D2O) from deuterium gas (D2), then separating D2O, and further electrolyzing it.

[0003] On the other hand, methods for separating hydrogen isotopes including light hydrogen (H), deuterium (D, 2 H), and tritium (T, 3 H) are known. Patent Document 2 discloses an alloy for separating hydrogen isotopes and a method for separating hydrogen isotopes using the same. The method described in Patent Document 2 discloses that a hydrogen storage alloy having a specific chemical structure is used, and each hydrogen isotope is sequentially occluded or released according to a change in pressure by the equilibrium occlusion pressure difference or the equilibrium release pressure difference of each of the plurality of hydrogen isotopes.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The use of raw materials containing deuterium gas (D2) and heavy water (D2O) (hereinafter collectively referred to as deuterium raw materials) is expanding. Deuterium raw materials are expensive, and their utilization efficiency is not necessarily high. As a result, the exhaust gases and effluents discharged from processes using deuterium raw materials contain unused deuterium gas and heavy water. It is desirable to recover and recycle deuterium gas and heavy water from such waste. The method described in Patent Document 1 involves first converting the recovered deuterium gas into heavy water, separating the heavy water, and then generating deuterium gas again by electrolysis. This method requires multiple chemical reaction steps from recovery to reuse. Furthermore, Patent Document 1 does not consider hydrogen isotopes or their separation.

[0006] A method for more efficiently reusing deuterium raw materials is desired. Furthermore, in order to recover and reuse deuterium raw materials, it is desirable that the hydrogen isotope purity is maintained in the reused deuterium raw materials. In view of this situation, one of the objectives of this disclosure is to provide a deuterium recycling method and a deuterium recycling apparatus that can recover deuterium (D2) contained in exhaust gas emitted from processes that utilize deuterium, and recycle it for reuse as deuterium (D2). [Means for solving the problem]

[0007] A method for recycling deuterium according to this disclosure includes a recovery step of recovering light hydrogen and deuterium by contacting exhaust gas, which is exhaust gas discharged from a process utilizing deuterium (D2) and contains light hydrogen (H2) and deuterium, with an adsorbent capable of adsorbing light hydrogen and deuterium; and a desorption step of desorbing light hydrogen and deuterium from the adsorbent. The desorption step includes a light hydrogen separation step carried out under a first condition in which light hydrogen is preferentially desorbed from the adsorbent; and a deuterium separation step carried out under a second condition in which deuterium is preferentially desorbed from the adsorbent. A method for recycling deuterium according to this disclosure includes a step of supplying the gas containing deuterium (D2) obtained in the deuterium separation step as a raw material gas in the process.

[0008] A deuterium recycling apparatus according to this disclosure is an apparatus installed in a facility that carries out a process utilizing deuterium (D2), and comprises an adsorption section that houses an adsorbent capable of adsorbing and desorbing light hydrogen and deuterium contained in the exhaust gas discharged from the process. [Effects of the Invention]

[0009] According to this disclosure, it is possible to recover deuterium contained in exhaust gases emitted from processes that utilize deuterium, recycle it, and reuse it as deuterium. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic diagram (first state) showing the configuration of the recycling device according to the embodiment. [Figure 2] Figure 2 is a schematic diagram (second state) showing the configuration of the recycling device according to the embodiment. [Figure 3] Figure 3 is a schematic diagram (third state) showing the configuration of the recycling device according to the embodiment. [Figure 4] Figure 4 is a schematic diagram (fourth state) showing the configuration of the recycling device according to the embodiment. [Figure 5] Figure 5 is a flowchart showing an overview of the recycling method according to the embodiment. [Modes for carrying out the invention]

[0011] [Summary of the Embodiment] First, embodiments of the recycling method and recycling apparatus relating to this disclosure will be listed and described. A method for recycling deuterium according to this disclosure includes a recovery step of recovering light hydrogen and deuterium by contacting exhaust gas, which is exhaust gas discharged from a process utilizing deuterium (D2) and contains light hydrogen (H2) and deuterium, with an adsorbent capable of adsorbing light hydrogen and deuterium; and a desorption step of desorbing light hydrogen and deuterium from the adsorbent. The desorption step includes a light hydrogen separation step carried out under a first condition in which light hydrogen is preferentially desorbed from the adsorbent; and a deuterium separation step carried out under a second condition in which deuterium is preferentially desorbed from the adsorbent. A method for recycling deuterium according to this disclosure includes a step of supplying the gas containing deuterium (D2) obtained in the deuterium separation step as a raw material gas in the process.

[0012] According to the recycling method described herein, in a process utilizing deuterium, deuterium and light hydrogen can be recovered from the exhaust gas discharged after the use of deuterium gas, and then hydrogen isotopes can be separated to improve the purity of hydrogen isotopes. These processes can be carried out in a closed system using a single apparatus, without involving chemical reactions.

[0013] In the recycling method described above, the adsorbent may be a hydrogen storage alloy. By using a hydrogen storage alloy, it is possible to adsorb exhaust gas containing deuterium and separate hydrogen isotopes without chemical reactions, by controlling the temperature conditions.

[0014] In the recycling method described above, the temperatures of the first condition and the second condition are different, and the first temperature in the first condition may be lower than the second temperature in the second condition. In other words, light hydrogen can be preferentially desorbed from the hydrogen storage alloy at the first temperature, and then deuterium can be desorbed at a higher temperature.

[0015] In the recycling method described above, the light hydrogen separation step and the deuterium separation step may be carried out continuously. By continuously controlling the temperature, the process from deuterium recovery to separation, purification, and reuse can be carried out more efficiently.

[0016] In the recycling method, the adsorption section that houses the adsorbent includes a first adsorption section and a second adsorption section provided in parallel with each other. Preferably, while the recovery step is being carried out in the first adsorption section, the light hydrogen separation step or the heavy hydrogen separation step is being carried out in the second adsorption section. By configuring it in this way, it becomes possible to continuously recycle heavy hydrogen and to more efficiently carry out the heavy hydrogen utilization process.

[0017] The heavy hydrogen recycling apparatus according to the present disclosure is an apparatus provided in a facility that carries out a process using heavy hydrogen (D2), and includes an adsorption section that houses an adsorbent capable of adsorbing and desorbing light hydrogen and heavy hydrogen contained in the exhaust gas discharged from the process. A facility equipped with this apparatus can recycle heavy hydrogen in a closed system using an adsorption tower, reduce the amount of expensive heavy hydrogen to be discarded, and efficiently carry out the process of using heavy hydrogen.

[0018] In the heavy hydrogen recycling apparatus, the adsorbent may be a hydrogen storage alloy. The hydrogen storage alloy can adsorb heavy hydrogen and light hydrogen, and can separate heavy hydrogen and light hydrogen using a temperature difference when desorbing them. According to this apparatus, since it is possible to recover heavy hydrogen and separate and purify hydrogen isotopes without involving a chemical reaction, it is possible to use the recycled heavy hydrogen while reducing the risk of impurity mixing in the heavy hydrogen utilization process.

[0019] In the deuterium recycling device, the adsorption part includes a first adsorption part and a second adsorption part provided in parallel with each other, and a first switching part for switching the piping so as to introduce the exhaust gas from the process into one of the first adsorption part and the second adsorption part, and a second switching part for switching the piping so as to introduce the gas containing deuterium (D2) from one of the first adsorption part and the second adsorption part into the process. It is preferable to be provided. According to this configuration, it is possible to supply the deuterium recycled from the other adsorption part to the process while performing the recovery in one adsorption part, and it is possible to more efficiently implement the deuterium utilization process.

[0020] [Specific examples of embodiments] Next, specific embodiments of the recycling device and the recycling method according to the present disclosure will be described while referring to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

[0021] (Recycling device) FIG. 1 is a schematic diagram showing the configuration of the recycling device according to the present disclosure. Referring to FIG. 1, the recycling device 1 is connected to a facility 50 that is a facility for implementing a process using deuterium (D2) gas. The facility 50 uses a gas containing deuterium (D2) as at least one of the raw materials used in the process implemented in the facility 50. Further, the facility 50 discharges a gas containing deuterium (D2) and light hydrogen (H2) as the exhaust gas from the process implemented in the facility 50. The facility 50 may be, for example, a deuterium synthesis device (deuterium gas production device, synthesis device for deuterated organic compounds, etc.), a semiconductor manufacturing device, an organic EL manufacturing device, etc., and is not particularly limited. The recycling device 1 may be provided as a part of the facility 50, or may be provided as an external device that can be attached to and detached from the facility 50.

[0022] The recycling device 1 includes a first pipe 11 connected to the discharge section of the equipment 50 and a second pipe 12 connected to the raw material supply section of the equipment 50. Between the first pipe 11 and the second pipe 12 is a recycling section 20 for recovery and hydrogen isotope separation. The recycling section 20 includes two adsorption cylinders (first adsorption section 13, second adsorption section 14). The first adsorption section 13 and the second adsorption section 14 each contain an adsorbent capable of adsorbing and desorbing light hydrogen and deuterium. The first adsorption section 13 and the second adsorption section 14 are arranged in parallel with each other. Being in parallel with each other means that a pipeline can be configured that passes only through the second adsorption section 14 without passing through the first adsorption section 13, and a pipeline can be configured that passes only through the first adsorption section 13 without passing through the second adsorption section 14.

[0023] The first adsorption section 13 and the second adsorption section 14 each include an adsorption cylinder for housing an adsorbent and an adsorbent housed in the adsorption cylinder. The adsorbent is an adsorbent capable of adsorbing and desorbing deuterium (D2) and light hydrogen (H2), and specifically may be a hydrogen storage alloy capable of adsorbing and desorbing deuterium (D2) and light hydrogen (H2), a porous coordination polymer (PCP / MOF) capable of adsorbing and desorbing deuterium (D2) and light hydrogen (H2), etc. It is preferable that the hydrogen storage alloy is capable of selectively adsorbing deuterium and light hydrogen from exhaust gas.

[0024] Examples of hydrogen storage alloys include AB5 type hydrogen storage alloys such as palladium-silver alloy (Pd-Ag), lanthanum-nickel alloy (LaNi5), and calcium-copper alloy (CaCu5); AB2 type hydrogen storage alloys such as magnesium-zinc alloy (MgZn2) and zirconium-nickel alloy (ZrNi2); AB type hydrogen storage alloys such as titanium-iron alloy (TiFe) and titanium-cobalt alloy (TiCo); A2B type hydrogen storage alloys such as magnesium-nickel alloy (Mg2Ni) and magnesium-copper alloy (Mg2Cu); and solid solution type alloys such as iron-vanadium alloy (Fe-V) and vanadium-niobium alloy (V-Nb). Of these, palladium-silver alloy (Pd-Ag) is preferred from the viewpoint of hydrogen isotope separation. The form of the hydrogen storage alloy may be any shape or size, such as powder, granules, or pellets.

[0025] The specific configurations of the first adsorption section 13 and the second adsorption section 14 are not particularly limited, but as an example, they may consist of a cylindrical outer casing made of metal filled with powdered hydrogen storage alloy. Although not shown in the figures, the first adsorption section 13 and the second adsorption section 14 may be equipped with various sensors such as pressure sensors and temperature sensors, and it is preferable that the internal temperature during hydrogen storage and release can be detected when controlling the hydrogen storage alloy to satisfy predetermined temperature conditions.

[0026] The first piping 11 has branches. The first piping 11 includes a first branch pipe 11A leading to the first adsorption section 13 and a second branch pipe 11B leading to the second adsorption section 14. An on-off valve V1 is provided in the first branch pipe 11A. An on-off valve V2 is provided in the second branch pipe 11B. By switching the on-off valves V1 and V2 open or closed, exhaust gas from the equipment 50 can be introduced into one or both of the first adsorption section 13 and the second adsorption section 14. The on-off valves V1 and V2 constitute the first switching section 30.

[0027] A second switching unit 40 is provided between the recycling unit 20 and the second piping 12. The second switching unit 40 switches the pipeline to introduce gas containing deuterium (D2) from one or both of the first adsorption unit 13 and the second adsorption unit 14 to the equipment 50 via the second piping 12. The second switching unit 40 is connected to pipes 41A and 41B that are connected to the outlet sides of the first adsorption unit 13 and the second adsorption unit 14, respectively. The second switching unit 40 is also connected to the first exhaust pipe 51 and the second exhaust pipe 61 that are connected to the outside of the recycling device 1. The second switching unit 40 includes six on-off valves V3, V4, V5, V6, V7, and V8.

[0028] The pipe 41A connected to the outlet side of the first adsorption section 13 is branched into two. One branch of pipe 41A is connected to the first exhaust pipe 51, and an on-off valve V3 is provided along the way. The other branch is a conduit that connects to the second pipe 12 and the second exhaust pipe 61, and an on-off valve V5 is provided along the way. The pipe 41B connected to the outlet side of the second adsorption section 14 is branched into two. One branch of pipe 41B is connected to the first exhaust pipe 51, and an on-off valve V4 is provided along the way. The other branch is a conduit that connects to the second pipe 12 and the second exhaust pipe 61, and an on-off valve V6 is provided along the way.

[0029] On-off valve V7 is installed in the middle of the second piping 12. On-off valve V8 is installed in the middle of the second exhaust pipe 61.

[0030] The second switching unit 40 allows the outlet pipe 41A of the first suction unit 13 to be switched between three states: one in communication with the first exhaust pipe 51, one in communication with the second exhaust pipe 61, and one connected to the equipment 50 via the second pipe 12. Similarly, the second switching unit 40 allows the outlet pipe 41B of the second suction unit 14 to be switched between three states: one in communication with the first exhaust pipe 51, one in communication with the second exhaust pipe 61, and one connected to the equipment 50 via the second pipe 12.

[0031] Figure 1 schematically shows an overview of the recycling device, and some measuring instruments such as thermometers and pressure gauges, as well as some piping, have been omitted. Furthermore, the configuration of the piping and valves in the switching section is not limited to the form shown in Figure 1, and it is acceptable as long as similar functionality can be achieved. In addition, although the example in Figure 1 has a configuration in which the recycling section includes two adsorption units, the number of adsorption units is not limited, and it may have only one adsorption unit, or three or more adsorption units arranged in parallel.

[0032] (Recycling methods) The deuterium recycling method according to this disclosure is preferably carried out in the apparatus described above. The material to be processed in the recycling method according to this disclosure is a gas discharged from a process utilizing deuterium (D2), and is a gas containing deuterium (D2) and light hydrogen (H2). Figure 5 shows a flowchart illustrating the outline of the recycling method according to this disclosure.

[0033] Referring to Figure 5, the device is prepared as a starting point. The preparation details are set as appropriate according to the specific configuration of the device. The gas to be processed supplied to the recycling device according to this disclosure may be pre-treated by dehumidification, dust removal, etc., using a dehumidifier or filter, if necessary.

[0034] In the recovery process (S10), light hydrogen and deuterium are recovered by bringing a gas containing light hydrogen and deuterium into contact with an adsorbent capable of adsorbing light hydrogen and deuterium. As explained in relation to Figure 1, this is the process of introducing the gas discharged from the equipment 50 into the first adsorption section 13 or the second adsorption section 14 of the recycling section 20. The gas discharged from a process utilizing deuterium contains a large amount of nitrogen, etc., used as a carrier gas, in addition to deuterium and light hydrogen. The hydrogen storage alloy contained in the adsorption section selectively adsorbs only hydrogen and deuterium, while other gases such as nitrogen are not adsorbed and are discharged outside the system as exhaust gas. The recovery process should be carried out under temperature and pressure conditions in which the hydrogen storage alloy efficiently adsorbs deuterium and light hydrogen, and the conditions are not particularly limited, but for example, when a palladium-silver alloy (Pd-Ag) is used as the hydrogen storage alloy, the recovery process can be carried out at atmospheric pressure and around 10-30°C (room temperature range).

[0035] Following the recovery process, a desorption process is carried out to desorb light hydrogen and deuterium from the adsorbent. The desorption process includes a light hydrogen separation process (S20) in which light hydrogen is preferentially desorbed from the adsorbent, and a deuterium separation process (S30) in which deuterium is preferentially desorbed from the adsorbent. The order in which the light hydrogen separation process (S20) and the deuterium separation process (S30) are carried out is not limited, but when a hydrogen storage alloy is used as the adsorbent, it is preferable to carry out the light hydrogen separation process (S20) first, and then the deuterium separation process (S30). The recycling method according to this disclosure separates hydrogen isotopes by desorbing light hydrogen and deuterium separately, taking advantage of the fact that the preferred desorption conditions for light hydrogen and deuterium are different. Note that the "light hydrogen separation process in which light hydrogen is preferentially desorbed" means that the amount, rate, or ratio of light hydrogen desorbed in the light hydrogen separation process is greater than the amount, rate, or ratio of light hydrogen desorbed in the deuterium separation process. Furthermore, a "deuterium separation process that preferentially desorbs deuterium" means that the amount, rate, or proportion of deuterium desorbed in the deuterium separation process is greater than the amount, rate, or proportion of deuterium desorbed in the light hydrogen separation process. It is preferable that deuterium and light hydrogen be completely separated, but some deuterium desorption may occur in the light hydrogen separation process, and some light hydrogen separation may occur in the deuterium separation process.

[0036] When a hydrogen storage alloy is used as the adsorbent, the light hydrogen separation step (S20) and the deuterium separation step (S30) can be carried out in accordance with the difference between the temperature suitable for desorption of light hydrogen and the temperature suitable for deuterium. The light hydrogen separation step (S20) and the deuterium separation step (S30) can be carried out by heating the hydrogen storage alloy, which is the adsorbent. Furthermore, the first temperature at which the light hydrogen separation step (S20) is carried out can be set to a lower temperature than the second temperature at which the deuterium separation step (S30) is carried out. The specific temperature conditions can be set according to the hydrogen storage alloy used and are not particularly limited, but for example, when a palladium-silver alloy (Pd-Ag) is used as the hydrogen storage alloy, the light hydrogen separation step can be set to about 40-60°C and the deuterium separation step to about 60-200°C. Furthermore, it is preferable that the temperature of the desorption steps (light hydrogen separation step and deuterium separation step) is higher than the temperature at which the recovery step is carried out.

[0037] The light hydrogen separation process (S20) and the deuterium separation process (S30) may be carried out continuously by heating the adsorbent. In this case, light hydrogen, which is an impurity component, is preferentially desorbed and discharged in the initial stage of the desorption process, and then deuterium can be desorbed and recycled thereafter. As explained with reference to Figure 1, in the light hydrogen separation process (S20), light hydrogen, which is an unwanted component, is discharged from the system through the second exhaust pipe 61 from the first adsorption unit 13 or the second adsorption unit 14. In the deuterium separation process (S30), the separated deuterium is supplied to the equipment 50 as recycled raw material gas through the second piping 12 (S40). The deuterium gas separated in the deuterium separation process may be used as is again as raw material gas in the deuterium utilization process, or it may be mixed with unused raw material gas and used as part of the raw material gas. In addition, various treatments such as concentration, dehumidification, and pressure adjustment may be carried out before it is used as raw material gas.

[0038] The aforementioned recycling method is preferably implemented in a device equipped with multiple adsorption units, as shown in Figure 1. When using a device with multiple adsorption units, hydrogen and deuterium can be recovered in one adsorption unit, and at the same time, hydrogen and deuterium can be desorbed from the other adsorption units to recycle deuterium. By repeating these steps, recycled deuterium can be continuously supplied to the deuterium utilization process.

[0039] Referring to Figures 1 to 4, an overview of the operation of the apparatus when continuously recycling deuterium will be explained. Figure 1 shows the state at time T1. Referring to Figure 1, at time T1, the on-off valve V1 in the first switching unit 30 is open and the on-off valve V2 is closed. In the second switching unit 40, the on-off valves V3, V6, and V8 are open, and the on-off valves V4, V5, and V7 are closed. At this time, the recovery process is carried out in the first adsorption unit 13. The exhaust gas containing deuterium gas and light hydrogen gas discharged from the equipment 50 is introduced into the first adsorption unit 13, where the deuterium and light hydrogen contained in the exhaust gas are adsorbed. Other components of the exhaust gas (such as nitrogen gas) pass through the first adsorption unit 13 and are discharged out of the system through the first exhaust pipe 51. In addition, the light hydrogen separation process is carried out in the second adsorption unit 14. The second adsorption unit 14 is heated to a temperature at which light hydrogen is released from the hydrogen storage alloy. The light hydrogen desorbed from the second adsorption section 14 is discharged outside the system through the second exhaust pipe 61.

[0040] After a predetermined time has elapsed from the state shown in Figure 1, or after a predetermined cumulative gas flow rate has been reached, the operation shown in Figure 2 proceeds. Figure 2 shows the state at time T2, which is later than T1. Referring to Figure 2, in the first switching unit 30, valve V1 is open and valve V2 is closed. In the second switching unit 40, valves V3, V6, and V7 are open, and valves V4, V5, and V8 are closed. At this time, the recovery process is carried out in the first adsorption unit 13, continuing from T1. The exhaust gas containing deuterium and light hydrogen gas discharged from the equipment 50 is introduced into the first adsorption unit 13, and the adsorption of deuterium and light hydrogen continues in the first adsorption unit 13. Other components of the exhaust gas are discharged out of the system through the first exhaust pipe 51. Meanwhile, the deuterium separation process is carried out in the second adsorption unit 14. The second adsorption unit 14 is further heated to a temperature at which deuterium is released from the hydrogen storage alloy. The deuterium desorbed from the second adsorption unit 14 is supplied to the equipment 50 as deuterium through the second piping 12.

[0041] After a predetermined time has elapsed from the state shown in Figure 2, or after a predetermined cumulative gas flow rate has been reached, the process proceeds to the operation shown in Figure 3. Figure 3 shows the state at time T3, which is later than T2. ​​Referring to Figure 3, in the first switching section 30, valve V2 is open and valve V1 is closed. In the second switching section 40, valves V4, V5, and V8 are open, and valves V3, V6, and V7 are closed. At this time, a recovery process is carried out in the second adsorption section 14. The exhaust gas containing deuterium gas and light hydrogen gas discharged from the equipment 50 is introduced into the second adsorption section 14, where deuterium and light hydrogen are adsorbed. Other components of the exhaust gas pass through the second adsorption section 14 and are discharged out of the system through the first exhaust pipe 51. In the first adsorption section 13, a light hydrogen separation process is carried out. The first adsorption section 13 is heated to a temperature at which light hydrogen is released from the hydrogen storage alloy. The light hydrogen desorbed from the first adsorption section 13 is discharged outside the system through the second exhaust pipe 61.

[0042] After a predetermined time has elapsed from the state shown in Figure 3, or after a predetermined cumulative gas flow rate has been reached, the process proceeds to the operation shown in Figure 4. Figure 4 shows the state at time T4, which is later than T3. Referring to Figure 4, in the first switching unit 30, valve V2 is open and valve V1 is closed. In the second switching unit 40, valves V4, V5, and V7 are open, and valves V3, V6, and V8 are closed. At this time, the recovery process continues in the second adsorption unit 14 from time T3. The exhaust gas containing deuterium and light hydrogen gas discharged from the equipment 50 is introduced into the second adsorption unit 14, where the adsorption of deuterium and light hydrogen continues. Other components of the exhaust gas are discharged out of the system through the first exhaust pipe 51. The first adsorption unit 13 is heated to a temperature at which deuterium is released from the hydrogen storage alloy. In the first adsorption section 13, a deuterium separation process is carried out, and the deuterium desorbed from the first adsorption section 13 is supplied to the equipment 50 as deuterium through the second piping 12.

[0043] Furthermore, the recycling method may include various steps in addition to the above-mentioned process, such as an adsorbent regeneration process and a temperature control process. Also, the time required for the recovery process, the light hydrogen separation process, and the deuterium separation process may be the same or different.

[0044] The embodiments disclosed herein should be understood in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended. [Explanation of Symbols]

[0045] 1 Recycling device, 11 First piping, 11A First branch pipe, 11B Second branch pipe, 12 Second piping, 13 First adsorption unit, 14 Second adsorption unit, 20 Recycling unit, 30 First switching unit, 40 Second switching unit, 41A Piping, 41B Piping, 50 Equipment, 51 First exhaust pipe, 61 Second exhaust pipe, V1, V2, V3, V4, V5, V6, V7, V8 On / off valves.

Claims

1. Deuterium (D ２ Exhaust gas emitted from a process that utilizes ) and light hydrogen (H ２ A recovery process in which exhaust gas containing ) and deuterium is brought into contact with an adsorbent capable of adsorbing light hydrogen and deuterium to recover light hydrogen and deuterium, A desorption step of desorbing light hydrogen and deuterium from the adsorbent, Includes, The aforementioned attachment / detachment process is, A light hydrogen separation step is carried out under a first condition in which light hydrogen is preferentially desorbed from the adsorbent, A deuterium separation step carried out under a second condition in which deuterium is preferentially desorbed from the adsorbent, Includes, Deuterium (D) obtained in the deuterium separation step ２ The process includes supplying a gas containing ) as a raw material gas in the process, Methods for recycling deuterium.

2. The adsorbent is a hydrogen storage alloy. The method for recycling deuterium according to claim 1.

3. The temperatures of the first condition and the second condition are different, and the first temperature in the first condition is lower than the second temperature in the second condition. The method for recycling deuterium according to claim 2.

4. The light hydrogen separation step and the deuterium separation step are carried out in succession. The method for recycling deuterium according to claim 3.

5. The adsorption section that accommodates the adsorbent includes a first adsorption section and a second adsorption section arranged in parallel to each other. At the same time that the recovery process is carried out in the first adsorption section, In the second adsorption section, the light hydrogen separation step or the deuterium separation step is performed. A method for recycling deuterium according to claim 1 or claim 2.

6. Deuterium (D ２ A device installed in equipment that carries out a process using ) The system includes an adsorption section that houses an adsorbent capable of adsorbing and desorbing light hydrogen and deuterium contained in the exhaust gas discharged from the process, Deuterium recycling equipment.

7. The adsorbent is a hydrogen storage alloy. The deuterium recycling apparatus according to claim 6.

8. The adsorption portion includes a first adsorption portion and a second adsorption portion arranged in parallel with each other. A first switching unit switches the pipeline to introduce exhaust gas from the process into one of the first adsorption unit and the second adsorption unit, Deuterium (D) is supplied to the process from either the first adsorption unit or the second adsorption unit. ２ A second switching section that switches the pipeline to introduce gas containing ) Equipped with, A deuterium recycling apparatus according to claim 6 or claim 7.

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