Electrolytic gas recombination device

Abstract

To provide an electrolytic gas recombination device that can prevent overheating of the catalyst due to the combustion of the electrolytic gas. [Solution] An electrolytic gas recombining apparatus that recombines two types of electrolytic gases generated by electrolysis by contacting them with a combustion catalyst, An electrolytic gas recombination apparatus comprising: a heat dissipation means for discharging the heat of combustion generated by the combustion catalyst to the outside; a heat conductive member provided in contact with the heat dissipation means; and a combustion catalyst layer provided in contact with the heat conductive member.

Description

Technical Field

[0001] The present invention relates to an electrolytic gas recombination device.

Background Art

[0002] A catalytic combustor is generally a device that makes difficult-to-burn fuel easier to burn by utilizing the power of a catalyst. The catalytic combustor is used, for example, for the concentration of heavy water as an electrolytic gas recombiner. When water containing heavy water is electrolyzed, more light water is electrolyzed and discharged as gas, and the heavy water concentration of the remaining water increases as the electrolysis progresses. On the other hand, when two types of electrolytic gases generated by electrolysis are recombined in an electrolytic gas recombination device, low-concentration heavy water can be obtained.

[0003] Conventional catalytic combustors have been used to activate the combustion reaction, such as supplying preheated gas to increase the catalyst temperature as shown in Patent Document 1. However, since electrolytic gas is extremely flammable, it is necessary to prevent overheating of the catalyst due to the combustion reaction of the electrolytic gas.

[0004] As a means for preventing overheating of the catalyst, for example, Patent Document ② proposes a technique of supplying hydrogen and oxygen obtained by electrolyzing together with a large amount of air to an electrolytic gas recombination device to remove the combustion heat with the air. However, since the moisture contained in the air is mixed into the recombined water and the heavy water concentration is lowered, it is not suitable for an electrolytic gas recombination device. Also, if the gas flow rate is small, the combustion heat cannot be sufficiently discharged, and the catalyst overheats, causing the operation to stop.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention has been made in view of the above circumstances, and its purpose is to provide an electrolytic gas recombination device that can prevent overheating of the catalyst due to the combustion of the electrolytic gas. [Means for solving the problem]

[0007] [1] An electrolytic gas recombining apparatus that recombines two types of electrolytic gases generated by electrolysis by contacting them with a combustion catalyst, An electrolytic gas recombination apparatus comprising: a heat dissipation means for discharging the heat of combustion generated by the combustion catalyst to the outside; a heat conductive member provided in contact with the heat dissipation means; and a combustion catalyst layer provided in contact with the heat conductive member.

[0008] [2] The electrolytic gas recombination apparatus described in [1] above, An electrolytic unit that generates electrolytic gas supplied to the electrolytic gas recombination device by electrolysis, and A collection unit for collecting the recombined material generated by the aforementioned electrolytic gas recombination apparatus, A hydrogen isotope separation apparatus having the following features.

[0009] [3] A water electrolysis type hydrogen isotope separation method using the hydrogen isotope separation apparatus described in [2] above, wherein the temperature of the combustion catalyst is 110°C or higher and 200°C or lower.

[0010] [4] The water electrolysis type hydrogen isotope separation method according to [3] above, wherein the hydrogen isotope separation apparatus is operated with the outlet side of the collection unit open. [Effects of the Invention]

[0011] According to the electrolytic gas recombination apparatus of the present invention, the temperature rise of the catalyst can be suppressed by heat conduction, thereby preventing overheating of the catalyst due to the combustion heat of the electrolytic gas. [Brief explanation of the drawing]

[0012] [Figure 1]Figure 1 shows one embodiment of the present invention, where (a) is a side view of a heat sink type electrolytic gas recombination device, (b) is an oblique view of the flange, (c) is a perspective view of the laminate of the combustion catalyst layer and the heat transfer plate, and (d) is a perspective view of the gasket. [Figure 2] Figure 2 shows one embodiment of the present invention, where (a) is a side view of a heat sink type electrolytic gas recombination device and (b) is a cross-sectional view along line AA. [Figure 3] Figure 3 shows one embodiment of the present invention, where (a) is a side view of a heat sink type electrolytic gas recombination device, (b) is a plan view of the top surface of the heat transfer plate, (c) and (e) are plan views of the combustion catalyst layer, (d) is a plan view of the spacer, and (f) is a plan view of the bottom surface of the heat transfer plate. [Figure 4A] Figure 4A is a side view of a heat sink type electrolytic gas recombination device, which is one embodiment of the present invention. [Figure 4B] Figure 4B shows the components of Figure 4A, where (a) is a plan view of the top surface of the heat transfer plate, (b), (d), (f), and (h) are plan views of the combustion catalyst layer, (e) is a top view of another heat transfer plate, (i) is a top view of another heat transfer plate, and (c) and (g) are plan views of the spacers. [Figure 5] Figure 5 shows one embodiment of the present invention, where (a) is a side view of a heat sink type electrolytic gas recombination device, (b) and (d) are plan views of the heat transfer plate (inside the housing), and (c) is a plan view of the combustion catalyst layer. [Figure 6] Figure 6 shows one embodiment of the present invention, where (a) is a side view of a heat sink type electrolytic gas recombination device and (b) is a plan view of the flange (combustion catalyst layer side). [Figure 7] Figure 7 shows one embodiment of the present invention, where (a) and (b) are schematic diagrams of a hydrogen isotope separation apparatus using a heat sink type electrolytic gas recombination apparatus. [Figure 8] Figure 8 shows the combustion rate of the electrolytic gas in the embodiment of the present invention. [Modes for carrying out the invention]

[0013] The present invention relates to an electrolytic gas recombination device that causes two types of electrolytic gases generated by electrolysis to contact a combustion catalyst to recombine the electrolytic gases, and includes a heat radiation means for discharging the combustion heat generated by the combustion catalyst to the outside, a heat conductive member provided in contact with the heat radiation means, and a combustion catalyst layer provided in contact with the heat conductive member. According to the above configuration of the present invention, heat can be efficiently discharged to the outside by the heat radiation means and the heat conductive member, so overheating of the catalyst can be prevented.

[0014] Hereinafter, the electrolytic gas recombination device of the present invention will be described with reference to the drawings showing preferred embodiments. Note that the electrolytic gas recombination device of the present invention is not limited to the configuration shown in the drawings, and the configuration can be appropriately changed. <{

[0015] In the electrolytic gas recombination device 1 of the present invention, a combustion catalyst layer � is held inside the housing, and a flow path for electrolytic gas is provided so as to contact the combustion catalyst layer 3. The electrolytic gas flow path is not particularly limited as long as the electrolytic gas contacts the combustion catalyst layer 3, and various known structures such as a meandering single groove, parallel grooves in parallel, and a lattice groove can be adopted, and the flow path length can be appropriately set to achieve a predetermined combustion rate.

[0016] In FIGS. 1 and 2, which are preferred examples of the embodiment, the housing of the electrolytic gas recombination device 1 is composed of a heat transfer plate 9 and a flange 2, and the combustion catalyst layer 3 is sandwiched between the heat transfer plate 9 and the flange 2. Further, the outer periphery of the combustion catalyst layer 3 is surrounded by a sealing member such as a frame-shaped gasket 17, and by sandwiching the gasket 17 between the heat transfer plate 9 and the flange 2, a gap corresponding to the thickness of the combustion catalyst layer 3 is prevented from occurring between the heat transfer plate 9 and the flange 2. On the surface of the flange 2 facing the combustion catalyst layer 3, a return flow path (meandering single groove) for electrolytic gas is provided by rib grooves 6, and the rib grooves 6 function as a flow path for electrolytic gas. Note that the flange 2, the gasket 17, and the heat transfer plate 9 are joined by joining means such as bolts 14, but they can be joined by any means.

[0017] In another preferred embodiment, as shown in Figures 3(a) and 4A, the housing of the electrolytic gas recombiner 1 is composed of heat transfer plates (9 in Figure 3(a); 9-1 to 9-4 in Figure 4A) and sealing members 15, and plate-shaped spacers 18 are provided between each combustion catalyst layer. Multiple parallel slit-shaped gaps are formed in the plate-shaped spacers 18, and these gaps function as gas flow paths 19c. As shown in Figure 3(a), by arranging the gas flow paths in parallel, such as gas flow path 19c, the electrolytic gas flow rate per gas flow path can be suppressed even if the total electrolytic gas flow rate is high. By using a folded flow path as shown in gas flow paths 19d and 19e in Figure 4A, the total flow path length can be increased. Although this slightly increases the stacking thickness of the electrolytic cell, it reduces the overall device area and allows for miniaturization of the electrolytic cell. Furthermore, in Figures 3(a) and 4A, the number of stacking stages can be set as appropriate, and the more stages there are, the better the combustion rate can be achieved even with a large amount of electrolytic gas.

[0018] In the electrolytic gas recombination apparatus 1 shown in Figure 3(a), the upper surface 9a of the heat transfer plate 9 in contact with the combustion catalyst layer 3b is provided with rib grooves 6a that supply electrolytic gas in a planar direction, communicating with the electrolytic gas introduction pipe 4 which supplies electrolytic gas in a vertical direction, as shown in Figure 3(b), so that the electrolytic gas supplied from the electrolytic gas introduction pipe 4 is supplied to the gas flow path 19c between the combustion catalyst layers 3a and 3b. Furthermore, the lower surface 9b of the heat transfer plate 9, which is in contact with the combustion catalyst layer 3a, is provided with rib grooves 6b formed in the planar direction and communicating with the steam exhaust pipe 8. A refrigerant pipe 13 is provided inside the heat transfer plate 9.

[0019] A frame-shaped gasket 17 with the same thickness as the combustion catalyst layer 3b is provided on the outer circumference of the combustion catalyst layer 3b. As shown in Figure 3(c), a slit-shaped void is formed between the combustion catalyst layer 3b and the gasket 17, which communicates with the rib groove 6a and allows electrolytic gas to flow through it. This void becomes a gas flow path 19a connected to the rib groove 6a. Similarly, a gasket 17 is provided on the outer circumference of the combustion catalyst layer 3a. As shown in Figure 3(e), a slit-shaped void (water vapor passage 19b) is formed between the combustion catalyst layer 3a and the gasket 17, and this void becomes a gas passage or water vapor passage, through which the gas is discharged to the water vapor discharge pipe 8 via the rib groove 6b.

[0020] A plate-shaped spacer 18 is provided between the combustion catalyst layer 3a and the combustion catalyst layer 3b. The spacer 18 has a slit-shaped void, which forms a gas passage 9c connecting the gas passage 19a and the water vapor passage 19b provided on both sides of the combustion catalyst layer.

[0021] In the electrolytic gas recombination apparatus 1 shown in Figure 4A, each combustion catalyst layer is provided in contact with a heat transfer plate, and a plate-shaped spacer 18 is provided between each combustion catalyst layer to form a gas flow path 19d (Figure 4B(c)) and a gas flow path 19e (Figure 4B(g)). As shown in Figures 4B(b), (d), (f), and (h), each combustion catalyst layer 3c, 3d, 3e, and 3f is provided with a frame-shaped gasket 17 on its outer circumference. Between the combustion catalyst layers 3c, 3d, 3e, and 3f and the gasket 17, slit-shaped voids are formed that communicate with rib grooves 6a, gas passages 19e, or rib grooves 6b, allowing electrolytic gas to flow. These voids become gas passages 19c, 19d, 19f, and 19h.

[0022] The electrolytic gas supplied from the electrolytic gas introduction pipe 4 in Figure 4B(a) is discharged from the water vapor discharge pipe 8 via the rib groove 6a, the gas flow path 19c in Figure 4B(b), the gas flow path 19d in Figure 4B(c), the gas flow path 19d in Figure 4B(d), the slit-shaped gas flow path 19e in Figure 4B(e), the gas flow path 19f in Figure 4B(f), the gas flow path 19e in Figure 4B(g), the water vapor flow path 19h in Figure 4B(h), and the rib groove 6b in Figure 4B(f). The gas flow path in Figure 4A has four stages, and Figure 4B is a component diagram for two stages. By stacking these components, a device with any number of stages can be created. A refrigerant pipe 13 is provided inside each heat transfer plate.

[0023] In Figure 5, which is a preferred example of another embodiment, the housing of the electrolytic gas recombiner 1 is composed of heat transfer plates 9e and 9f and a sealing member 15, and has a combustion catalyst layer 3g and a highly thermally conductive porous body 16 which is a heat conducting member inside. The combustion catalyst layer 3g is provided in contact with both sides of the highly thermally conductive porous body 16, and the voids between the catalysts constituting the combustion catalyst layer 3g and the voids between the highly thermally conductive porous body 16 function as gas flow paths. The white arrows in the figure indicate the direction of electrolytic gas flow. As shown in Figure 5(b), the upper surface of the heat transfer plate 9f is provided with rib grooves 6c that are in parallel and in the planar direction and communicate with the electrolytic gas introduction pipe 4 in order to supply the supplied electrolytic gas over a wide area. Furthermore, as shown in Figure 5(d), the lower surface of the heat transfer plate 9e is provided with a steam exhaust pipe 8 and rib grooves 6d that are in communication with the steam exhaust pipe 8 and are formed in parallel in the surface direction. In the configuration shown in Figure 5, multiple layers of combustion catalyst layer 3g and high thermal conductivity porous body 16 may be provided inside.

[0024] Figure 6(a), which is a preferred example of another embodiment, has the same configuration as Figure 1 except that two gas inlet pipes 4a and 4b are provided. Note that the bolt hole 14a is omitted in Figure 6(b). As shown in Figure 6(b), a recess is formed in flange 2a to serve as a gas mixing chamber 24 for mixing two types of electrolytic gas supplied from electrolytic gas introduction pipes 4a and 4b. Similar to the gas mixing chamber 24, a rectifier plate 25 is formed by a combination of recesses and non-recesses, allowing gas to flow through the recessed areas. Furthermore, a recess that serves as the pre-combustion chamber 26 and a rib groove 6 that serves as a gas passage are formed. In addition, to improve combustion efficiency, the pre-combustion chamber 26 may be provided with recessed and non-recessed portions, and protruding objects 26a of any shape may be formed by protruding irregularities to provide obstacles to the gas flow. The shape of the rib groove 6 is not limited, as with other embodiments.

[0025] The following describes each component shown in Figure 1. Note that Figures 2-6 have the same components as Figure 1, so their descriptions are omitted.

[0026] The combustion catalyst layer 3 is a catalyst that contributes to the recombination of electrolytic gases. When two types of electrolytic gases generated by electrolysis come into contact with the catalyst, it has the function of producing a recombined product through a combustion reaction. The material of the combustion catalyst constituting the combustion catalyst layer 3 can be selected from known catalysts having the above function according to the type of electrolytic gas, and one or more known alloying elements may be added as needed. For example, platinum, gold, silver, ruthenium, rhodium, and iridium are highly active catalysts, and alloys containing these elements, such as platinum-gold, platinum-palladium, platinum-rhodium, platinum-iridium, platinum-nickel, platinum-tungsten, and platinum-cobalt catalysts, are also known to be highly active.

[0027] The combustion catalyst layer 3 may consist only of catalyst metal, but considering durability such as strength and ease of replacement, a configuration in which the catalyst is supported on a substrate is preferred. Various known substrates can be used as the substrate on which the catalyst is supported, having heat resistance that does not deteriorate due to combustion heat and excellent thermal conductivity. Examples include various known porous materials such as carbon paper; various known metal foils such as SUS foil, nickel foil, and stainless steel foil; and various known metal substrates. However, the substrate is not particularly limited as long as it has the above characteristics. The amount of catalyst supported on the substrate can be adjusted as appropriate to obtain the desired combustion rate of the electrolytic gas.

[0028] The size of the combustion catalyst layer 3 is preferably set such that the contact area with the electrolytic gas flowing through the electrolytic gas recombination device 1 is large. The larger the contact area between the catalyst and the electrolytic gas, and the longer the contact time, the higher the combustion rate of the electrolytic gas can be. A higher combustion rate of the electrolytic gas is preferable, for example, 90% or more, more preferably 95% or more, even more preferably 98% or more, even more preferably 99% or more, and most preferably 100%. It is desirable to appropriately adjust the area of ​​the combustion catalyst layer 3 in consideration of the amount of electrolytic gas supplied so as to achieve the above combustion rate. The combustion rate of the electrolytic gas is a value calculated based on the formula [(Qin-Qout) / Qin] from the sum of the generated flow rates of hydrogen gas and oxygen gas calculated from the electrolytic current value (Qin) and the exhaust gas flow rate from the electrolytic gas recombination device 1 (Qout).

[0029] The sealing member 15 is not limited to any material that can ensure airtightness of the housing, and various known materials such as synthetic rubber such as fluororubber and resins can be used.

[0030] The thermal conductive member has the function of transferring the heat of combustion generated by the combustion catalyst to the heat dissipation means. Any thermal conductive member that has the above function can be used, and various known thermal conductive members can be used, such as metals like copper, silver, aluminum, nickel, stainless steel, or alloys thereof, or carbon materials. The alloying element can be appropriately selected from one or more known alloying elements as needed.

[0031] The shape of the thermally conductive member is not particularly limited, and examples include plate-shaped members such as the heat transfer plate 9 shown in Figure 1, and granular members such as the highly thermally conductive porous body 16 shown in Figure 5. Furthermore, the presence or absence of pores on the surface of the highly thermally conductive porous body 16 is not a requirement. The combustion catalyst layer 3 and the heat conduction member only need to be able to transfer the combustion heat from the combustion catalyst layer 3 to the heat conduction member, and the contact state between the combustion catalyst layer 3 and the heat conduction member is not limited. For example, the heat conduction member only needs to be in contact with one side of the combustion catalyst layer 3. The contact area between the heat conduction member and the combustion catalyst layer 3 is not particularly limited, but the larger the area of ​​the heat conduction member in contact with the combustion catalyst layer 3, the higher the thermal conductivity. Because it becomes difficult to supply electrolytic gas to the catalyst at the contact surface, if the substrate of the combustion catalyst layer is a porous material such as carbon paper, it is desirable to have a structure in which the contact area is about 50% and the remaining 50% is exposed in the gas groove. If the substrate of the combustion catalyst layer 3 is metal foil, it is desirable to make the grooved heat conduction plate that it contacts a porous material or to reduce the contact area to 50% or less. For example, in Figures 1 and 2, half of one side of the combustion catalyst layer 3 (50% of the contact area) is in contact with the heat transfer plate 9.

[0032] The heat dissipation means has the function of releasing the heat of combustion generated in the combustion catalyst to the outside. In this invention, the heat of combustion generated in the combustion catalyst layer 3 by the recombination of electrolytic gases is released to the outside by heat conduction to prevent overheating of the combustion catalyst layer 3. Specifically, the heat dissipation means and a heat conducting member provided in contact with the heat dissipation means release the heat of combustion to the outside. In this invention, the heat dissipation member and the heat conducting member function as a heat sink that removes heat of combustion from the combustion catalyst layer 3 (hereinafter, the heat dissipation member and the heat conducting member may be collectively referred to as a heat sink). The heat dissipation means is not particularly limited as long as it has the function of releasing the combustion heat described above. Examples include the heat dissipation fins 10 shown in Figure 1, the refrigerant pipes 13 embedded in a heat conductive member as shown in Figure 2, and various known heat pipes that utilize the evaporation and condensation of a working liquid for heat transfer, although these are not shown. The heat dissipation means and the heat conductive member only need to be in contact for heat conduction. For example, the heat dissipation means may be connected to the outside of the heat conductive member for heat dissipation, or the heat dissipation means may be provided inside the heat conductive member for heat dissipation. Alternatively, for example, refrigerant pipes coated with a catalyst may be placed in the gas flow path shown in Figures 3(a), 4A, and 5(a). The pipe portion of the refrigerant pipe functions as a heat conductive member, and the refrigerant flowing inside functions as the heat dissipation means.

[0033] For example, in Figure 1, by connecting heat dissipation fins 10, which are heat dissipation means, to the outer surface of the heat transfer plate 9, which is a heat conductive member, heat is transferred from the combustion catalyst layer 3 to the heat transfer plate 9, and then from the heat transfer plate 9 to the heat dissipation fins 10, and thus dissipated. If necessary, the heat dissipation efficiency of the heat dissipation fins 10 can be increased by providing an air cooling fan 11. Furthermore, in Figure 2, for example, a refrigerant pipe is provided inside the heat transfer plate 9, which is a heat conductive member, and heat is dissipated by the refrigerant circulating in the refrigerant pipe 13, which is a heat dissipation means. Specifically, heat is transferred from the combustion catalyst layer 3 to the heat transfer plate 9, and then from the heat transfer plate 9 to the refrigerant pipe 13 and the refrigerant, and the heat is dissipated to the outside by the refrigerant circulating in the refrigerant pipe 13. If necessary, a means to remove the heat from the refrigerant, such as a radiator (not shown), may be provided to circulate the refrigerant. The refrigerant pipe 13 may be a straight pipe or a coiled pipe, but using a coiled pipe can further enhance the cooling effect. The refrigerant may be a liquid or a gas, and various known refrigerants can be used.

[0034] The heat dissipation means may be provided with cooling-enhancing means as needed. The cooling-enhancing means has the function of further increasing the efficiency of combustion heat release of the heat dissipation means. The cooling-enhancing means only needs to have the above-mentioned cooling function, and various known cooling-enhancing means can be used, such as fans. In addition, one or more cooling-enhancing means may be used in combination as needed. For example, the cooling fan 11 in Figure 1 is an example of a cooling-enhancing means that can be optionally provided as needed. The cooling fan 11 is provided in contact with the end of the heat dissipation fin 10, and the airflow caused by the rotation of the cooling fan 11 can enhance the temperature cooling effect of the heat dissipation fin 10. The installation position of the cooling-enhancing means is not particularly limited as long as it has a temperature-reducing effect on the heat dissipation means, and the cooling means may be provided in contact with the heat dissipation means or not.

[0035] The electrolytic gas recombination apparatus 1 of the present invention may be provided with means for heating the catalyst (hereinafter referred to as catalyst heating means) as needed. Providing catalyst heating means allows the catalyst to be preheated during operation of the electrolytic gas recombination apparatus 1, shortening the time it takes for the catalyst temperature to reach a predetermined temperature. Various known heaters can be used as catalyst heating means. Furthermore, the installation position of the catalyst heating means is not particularly limited as long as it can heat the combustion catalyst layer 3. For example, in Figure 1, the heater 11 is set on the outside of the flange 2, but this is not limited to this, and it may be on any side of the heat transfer plate 9 or on any side of the heat dissipation fin 10 where the cooling fan 11 is not provided. Alternatively, the heater 11 may be enclosed within the heat transfer plate 9. Similarly in Figure 2, the heater can be installed at any position, and for example, the heater and refrigerant pipe 13 may be enclosed within the heat transfer plate 9.

[0036] The introduction pipe for the electrolytic gas supplied to the electrolytic gas recombination apparatus 1 of the present invention can be provided at any location and is not particularly limited. Furthermore, the two types of electrolytic gases generated by electrolysis may be mixed before being supplied to the electrolytic gas recombination apparatus 1 and the mixed gas may be introduced into the electrolytic gas recombination apparatus 1, or the two types of electrolytic gases may be mixed within the electrolytic gas recombination apparatus 1. In addition, the recombined electrolytic gas product generated within the electrolytic gas recombination apparatus 1 may be removed by providing a discharge pipe at any location. Figures 1 to 5 show that the electrolytic gases are pre-mixed and supplied to the electrolytic gas recombination device 1 from the electrolytic gas introduction pipe 4. The recombined material generated in the electrolytic gas recombination device 1 is discharged from the discharge pipe 8. In Figure 6, two types of electrolytic gases are supplied to the electrolytic gas recombination unit 1 from electrolytic gas inlet pipes 4a and 4b, respectively. The recombined product generated within the electrolytic gas recombination unit 1 is discharged from the discharge pipe 8.

[0037] Next, a hydrogen isotope separation apparatus, which is one embodiment of the present invention and is equipped with an electrolytic gas recombination apparatus, will be described. The hydrogen isotope separation apparatus of the present invention comprises an electrolytic gas recombination apparatus of the present invention, an electrolytic unit that generates an electrolytic gas supplied to the electrolytic gas recombination apparatus by electrolysis, and a collection unit that collects the recombined product generated in the electrolytic gas recombination apparatus.

[0038] The hydrogen isotope separation apparatus of the present invention will be described below with reference to the drawings showing a preferred embodiment. Note that the electrolytic gas recombination apparatus of the present invention is not limited to the illustrated example configuration, and the configuration can be modified as appropriate. Figures 7(a) and 7(b) are schematic diagrams of the hydrogen isotope separation apparatus of the present invention. In the illustrated example, only the electrolytic gas is supplied to the electrolytic gas recombination apparatus, but the present invention is not limited to this, and the electrolytic gas may also contain inert gases such as nitrogen or helium, or oxygen-containing gases such as air or oxygen. When using air, it is preferable to dry the air beforehand to remove moisture before use. Figure 1 shows the electrolytic gas recombination apparatus 1 of the present invention, which has already been described.

[0039] The electrolytic unit 20 is a device that generates electrolytic gas supplied to the electrolytic gas recombination device 1 by electrolysis. The configuration of the electrolytic unit 20 is not particularly limited, and various known electrolytic units can be used. In the illustrated example, it consists of a membrane electrode assembly 22 in which an anode and a cathode are joined to both sides of an electrolyte membrane that is conductive to hydrogen ions, and an anode chamber 21 on the anode side and a cathode chamber 23 on the cathode side separated by the membrane electrode assembly 22. Electrolysis using a separation membrane, such as the membrane electrode assembly 22, eliminates the need for dilution with helium or other substances compared to using an alkaline electrolytic cell without a separation membrane, and also simplifies the apparatus configuration. Therefore, the generated hydrogen and oxygen can be supplied to the electrolytic gas recombination device 1 without dilution and burned, contributing to the miniaturization of the apparatus. In other words, since dilution gas hinders contact between the electrolytic gas and the catalyst, it is necessary to increase the area of ​​the combustion catalyst layer, but in this invention, where dilution gas is unnecessary, the area of ​​the combustion catalyst layer can be reduced, thus enabling the miniaturization of the apparatus. Furthermore, there is no need to add electrolyte as in alkaline electrolysis, and therefore a distillation device to remove added electrolyte is also unnecessary, further simplifying the apparatus. The electrolyte membrane constituting the membrane electrode assembly 22 is not particularly limited; any membrane that generates oxygen and hydrogen by water electrolysis can be used. For example, the membrane electrode assembly 22 preferably consists of a Nafion membrane as the solid electrolyte, an iridium-based catalyst as the anode, and a platinum-based catalyst as the cathode.

[0040] The oxygen-side gas-liquid separator 30 is a tank that stores raw water before electrolysis, specifically heavy water of any concentration, and electrolytic gas, specifically oxygen, produced by electrolysis in the electrolysis unit 20. Various known separators can be used for the oxygen-side gas-liquid separator 30. Alternatively, a raw water tank and an electrolytic gas tank may be provided instead of the oxygen-side gas-liquid separator 30.

[0041] The hydrogen-side gas-liquid separator 31 is a tank that stores concentrated water produced by electrolysis in the electrolysis unit 20 and the electrolytic gas, specifically hydrogen, produced by electrolysis. Various known separators can be used for the hydrogen-side gas-liquid separator 31. Alternatively, a concentrated water tank and an electrolytic gas tank may be provided instead of the hydrogen-side gas-liquid separator 31.

[0042] The oxygen-side raw water circulation pump 32 is a means of supplying raw water to the anode chamber 21 of the electrolysis unit 20. The oxygen-side raw water circulation pump 32 can use various known supply means such as pumps.

[0043] The oxygen-side gas-liquid separator 30 and the hydrogen-side gas-liquid separator 31 are provided with a cathode-side gas supply pipe and an anode-side gas supply pipe for supplying the internal electrolytic gas to the electrolytic gas recombination device 1. In the illustrated example, the cathode chamber gas supply pipe and the anode chamber gas supply pipe are connected before the electrolytic gas recombiner 1 (gas induction pipe coupling T-joint), and this gas induction pipe coupling T-joint is connected to the electrolytic gas recombiner 1 by the electrolytic gas introduction pipe 4. Alternatively, the cathode chamber gas supply pipe and the anode chamber gas supply pipe may be connected to the electrolytic gas recombiner 1 as described above (Figure 6).

[0044] The collection unit 33 is a means for collecting the recombined material generated in the electrolytic gas recombiner. The collection unit 33 only needs to have the above function, and various known collection units can be used. A cold trap is a suitable example of the collection unit 33. It is preferable to provide an exhaust gas pipe to the collection unit 33 so that exhaust gas can be discharged from the collection unit 33 as appropriate.

[0045] The nitrogen purging nitrogen cylinder 34 is a nitrogen gas cylinder used to replace the atmosphere inside the water electrolysis type hydrogen isotope separation apparatus with nitrogen. By opening and closing valves 41, 42, 43, and 44 before and after operation of the water electrolysis type hydrogen isotope separation apparatus, nitrogen gas can be supplied from the nitrogen cylinder 34 into the apparatus, thereby exhausting the gas in the system and replacing it with nitrogen.

[0046] The following describes a water electrolysis type hydrogen isotope separation method using the water electrolysis type hydrogen isotope separation apparatus of the present invention, with reference to Figure 7(a), which is a preferred embodiment. Note that the water electrolysis type hydrogen isotope separation method of the present invention is not limited to the configuration shown in the illustration and the conditions described below, and these can be modified as appropriate. Figure 7(b) is a system diagram when the electrolytic gas is supplied to the electrolytic gas recombination apparatus 1 without pre-mixing, and is the same as Figure 7(a) except that the electrolytic gas is introduced separately into the electrolytic gas recombination apparatus 1 from gas introduction pipes 4a and 4b without pre-mixing in the T-tube.

[0047] It is preferable to open and close valves 41, 42, 43, and 44 before starting operation of the device to supply nitrogen gas from the nitrogen cylinder 34 and exhaust the gas in the system to replace it with nitrogen. Furthermore, before starting operation, it is preferable to preheat the catalyst to a predetermined temperature, for example, a temperature at which condensation does not occur, preferably around 105°C, by turning on the heater 12 provided in the electrolytic gas recombination device 1. It is also preferable to turn off the heater 12 once the predetermined preheating temperature has been reached. Furthermore, it is preferable to keep the pressure inside the electrolytic gas recombination device 1 at atmospheric pressure while operating with the valve 42 downstream (outlet side) of the cold trap 33 open. By operating with the valve 42 open, even if a problem occurs during operation, the electrolytic gas and recombined materials inside the device will be released into the atmosphere as exhaust gas, thereby increasing operational safety.

[0048] Heavy water (hereinafter referred to as raw water) that has been pre-adjusted to a desired concentration is supplied to the oxygen-side gas-liquid separator 30. When the pump 32 is operated, the raw water stored in the oxygen-side gas-liquid separator 30 is supplied to the anode chamber 21 of the electrolysis unit 20. When a direct current is applied to the electrolysis unit 20, the raw heavy water in the anode chamber 22 is electrolyzed and oxygen bubbles are generated, and at the same time, heavy water containing deuterium and hydrogen, along with protons that permeate the membrane electrode assembly 22, flows into the cathode chamber 23. The oxygen gas generated in the anode chamber 21 by electrolysis is sent to the oxygen-side gas-liquid separator 30, and the high-concentration heavy water with a high deuterium concentration and the electrolytic gas (hydrogen) with a low deuterium concentration generated in the cathode chamber 23 are sent to the hydrogen-side gas-liquid separator 31. The oxygen in the oxygen-side gas-liquid separator 30 and the hydrogen containing deuterium in the hydrogen-side gas-liquid separator 31 are mixed in a T-tube before the electrolytic gas recombiner 1 and sent to the electrolytic gas recombiner 1 via the inlet pipe 4. When the mixed gas comes into contact with the catalyst in the electrolytic gas recombination unit 1, it recombines to become water vapor containing heavy water, which is then discharged through the discharge pipe 8 and liquefied and recovered in the cold trap 33.

[0049] When using the electrolytic gas recombination device 1 of the present invention, combustion heat can be released to the outside, so the combustion catalyst does not overheat. It is desirable to maintain the catalyst temperature between 110°C and 200°C during operation. If the catalyst temperature is too low, the recombined product (liquid) produced by combustion may cover the catalyst, inhibiting the recombination reaction. Conversely, if the catalyst temperature is too high, the sealing material used in the electrolytic gas recombination device may deteriorate. It is desirable to adjust the catalyst temperature by, for example, providing an air-cooling fan 11 in the electrolytic gas recombination device 1 and controlling its ON / OFF state as needed. As electrolysis continues, the amount of raw water in the oxygen-side gas-liquid separator 30 decreases, and the amount of concentrated heavy water in the hydrogen-side gas-liquid separator 31 increases. Therefore, by opening valve 40, for example, the concentrated heavy water in the hydrogen-side gas-liquid separator 31 can be returned to the oxygen-side gas-liquid separator 30, allowing for re-electrolysis using heavy water with a higher concentration than the initial raw material heavy water. In addition, although the heavy water concentration of deuterium recovered in the cold trap 33 is lower than that of the raw material heavy water, high-concentration heavy water can be recovered by returning it to the raw material tank and repeating the re-electrolysis. After operation is complete, it is preferable to open and close valves 41, 42, 43, and 44 to supply nitrogen gas from the nitrogen cylinder 34 and exhaust the gas in the system to replace it with nitrogen. [Examples]

[0050] The present invention will be described in more detail below with reference to examples, but the present invention is not limited by the following examples, and it is certainly possible to implement it with appropriate modifications within the scope that is consistent with the spirit of the preceding and following descriptions, and all such modifications are included within the technical scope of the present invention.

[0051] Heavy water concentration was performed using the hydrogen isotope separation apparatus shown in Figure 7(a), which is equipped with the electrolytic gas recombination apparatus 1 shown in Figure 1. The electrolytic unit 20 has an electrode area of ​​25 cm². 2 A stack of four cells was constructed. An indium-based catalyst was used for the anode, a platinum-based catalyst for the cathode, a Nafion membrane for the electrolyte membrane, and titanium for the flow plate. Cooling water was circulated to maintain the cell temperature at approximately 25°C. The total electrode area was 100 cm². 2 That's what I decided. The electrolytic gas recombination device 1 includes a combustion catalyst (catalyst layer area 64 cm²). 2 Platinum nanoparticles were used as the support material. The platinum nanoparticles were supported on carbon paper (platinum load: 0.5 mg / cm³). 2 The combustion catalyst layer 3 was attached to the heat transfer plate 9 of a heat sink, which consists of a heat transfer plate 9 (oxygen-free copper), heat dissipation fins 10 (oxygen-free copper), and an air-cooling fan 11. The combustion catalyst layer 3 was also sandwiched between the heat transfer plate 9 and the surface of the flange 2 (SUS material) where a meandering rib groove was formed, and the heat transfer plate 9 and flange 2 were screwed together to ensure close contact between the combustion catalyst layer 3 and the heat transfer plate 9. The thermal resistance of the heat sink was 0.1 W / °C or less. The temperature of the center of the heat transfer plate 9 was detected by a thermocouple, and the air-cooling fan 11 was set to turn ON when the temperature of the heat transfer plate 9 reached 125°C and OFF when it reached 120°C, in order to maintain a temperature of 120°C. The cold trap 33 was filled with ice water to bring the temperature to 0°C.

[0052] Using a hydrogen isotope separation apparatus with the above configuration, 2 liters of heavy water with a heavy water concentration of 96% were placed in the oxygen-side gas-liquid separator 20 as raw material heavy water to concentrate the heavy water. First, valves 41, 42, 43, and 44 were opened to purge the hydrogen isotope separator with nitrogen. Then, valves 41, 43, and 44 were closed, but valve 42 remained open when operation began. The heater 12 attached to the flange 2 of the electrolytic gas recombination device 1 shown in Figure 1 was turned ON, and when the temperature of the heat transfer plate 9 reached 105°C, the heater was turned OFF.

[0053] The raw water in the oxygen-side gas-liquid separator 30 was supplied to the anode chamber 21 at a rate of 50 mL / min by the pump 32. Electrolysis was performed by passing a current of 50 A through the electrolysis unit 20 to generate electrolytic gas. The oxygen generated in the electrolysis unit 20 and hydrogen containing hydrogen isotopes are mixed in a T-tube before the electrolytic gas recombination device 1, and then supplied to the serpentine rib groove 6 of the flange 2 through the mixed gas introduction hole 5 of the flange 2. As they flow through the rib groove, they come into contact with the catalyst, react and recombine, and are discharged as water vapor from the water vapor discharge hole 7. They are then liquefied and recovered in the cold trap 33. Unreacted electrolytic gas discharged along with the water vapor is discharged from the valve 42. Furthermore, the concentrated water in the hydrogen-side gas-liquid separator 31 was returned to the oxygen-side gas-liquid separator 30 by automatically opening and closing a valve using a liquid level gauge installed inside the separator.

[0054] The rated electrolytic current of the above device was set to 50A, and heavy water was concentrated by applying a current of 50A for 16 hours. As a result, 96% heavy water could be concentrated to 99.7%. Furthermore, the heat transfer plate temperature of the electrolytic gas recombination device 1 was maintained within the range of 118-126°C during operation, and combustion heat was stably released to the outside, thus preventing overheating of the catalyst. In this experiment, an extremely high combustion rate (99%) was achieved.

[0055] Experimental results showed that the water electrolysis type hydrogen isotope separation apparatus of the present invention has a simpler configuration because it does not require the circulation of an inert gas as in conventional systems, and it can be operated safely because the catalyst installed in the electrolytic gas recombination unit does not overheat, and a high combustion rate can be obtained.

[0056] The combustion rate was calculated using the measured exhaust gas flow rate. An integrated flow meter was installed downstream of valve 42 to collect the exhaust gas in water and measure its volume, thereby measuring the exhaust gas flow rate. A current of 0.5A was supplied to the electrolysis unit 20, and after the nitrogen gas in the system was discharged, the current was increased to 50A and the exhaust gas flow rate was measured. The exhaust gas flow rate was measured over time from the start of current supply and the results were as follows. When 0.5A was introduced into the electrolytic cell, the exhaust gas flow rate decreased rapidly over time: 100mL / min after 1 minute, 60mL / min after 3 minutes, 10mL / min after 10 minutes, 1mL / min after 20 minutes, and 0.5mL / min after 30 minutes. However, even after further time, the exhaust gas flow rate did not reach zero, but settled at a constant value.

[0057] The large exhaust gas flow rate when the electric current is first applied is due to the nitrogen inside the device being pushed out by the electrolytic gas. This phenomenon only occurred when the electric current was first applied after the nitrogen gas purge.

[0058] When the electrolytic gas undergoes complete combustion in the catalytic combustor, the exhaust gas flow rate should be zero. Exhaust gas detected more than 30 minutes after the start of the test is unreacted electrolytic gas.

[0059] After operating at a current of 50A for 16 hours, the power supply was stopped to shut down the system. Thirty seconds after shutdown, each valve was opened to supply nitrogen from nitrogen cylinder 34 to perform a nitrogen purge, expelling the electrolytic gas from the system and filling it with nitrogen. Then, all valves were closed to end the test.

[0060] Figure 8 is a graph showing the relationship between combustion rate and electrolysis current when the electrolysis current is gradually increased from 5A to 50A after the start of operation. Gradually increasing the electrolysis current eliminates the large amount of exhaust gas that appears at the start of operation. As is also clear from this figure, the combustion rate at an electrolysis current of 50A is 99%, showing an extremely high combustion rate. [Explanation of Symbols]

[0061] 1. Electrolytic gas recombination device 2, 2a Flange 3, 3a, 3b, 3c, 3d, 3e, 3f, 3g combustion catalyst layer 4, 4a, 4b Electrolytic gas introduction tubes 5 Electrolytic gas introduction port 6, 6a, 6b, 6c, 6d Rib grooves 7. Steam outlet 8. Steam discharge pipe 9, 9a, 9b, 9c, 9d, 9e, 9f, 9g, 9h, 9-1, 9-2, 9-3, 9-4 Heat exchanger plate 10 heat dissipation fins 11. Cooling fan 12 Heater 13 Refrigerant pipes 14 volts 14a Bolt hole 15 sealing member 16. High thermal conductivity porous material 17 Gasket 18 Spacers 19, 19a, 19c, 19d, 19e, 19f, 19g gas flow path 19b, 19h Steam flow path 20 Electrolytic Units 21 Anode chamber 22 Membrane electrode assembly 23 Cathode Chamber 24 Gas mixing chamber 25 Rectifier plate 26. Pre-combustion chamber 26a Protrusions 27. Rear combustion chamber (serpentine groove) 30. Oxygen-side gas-liquid separator, 31. Hydrogen-side gas-liquid separator, 32 pumps 33 Collection Unit 34 Nitrogen Cylinders 40, 41, 42, 43, 44 Valves

Claims

1. An electrolytic gas recombining apparatus that recombines two types of electrolytic gases generated by electrolysis by contacting them with a combustion catalyst, An electrolytic gas recombination apparatus comprising: a heat dissipation means for discharging the heat of combustion generated by the combustion catalyst to the outside; a heat conductive member provided in contact with the heat dissipation means; and a combustion catalyst layer provided in contact with the heat conductive member.

2. The electrolytic gas recombination apparatus described in claim 1, An electrolytic unit that generates electrolytic gas supplied to the electrolytic gas recombination device by electrolysis, and A collection unit for collecting the recombined material generated by the aforementioned electrolytic gas recombination apparatus, A hydrogen isotope separation apparatus having the following features.

3. A method for separating hydrogen isotopes by water electrolysis using the hydrogen isotope separation apparatus according to claim 2, wherein the temperature of the combustion catalyst is 110°C or higher and 200°C or lower.

4. The water electrolysis type hydrogen isotope separation method according to claim 3, wherein the hydrogen isotope separation apparatus is operated with the outlet side of the collection unit in an open state.

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