Organic hydride production equipment and organic hydride production system

Abstract

This organic hydride manufacturing device 2 comprises: a membrane electrode assembly 8 in which an anode electrode 10 and a cathode electrode 12 are stacked so as to sandwich a membrane 14; a cathode channel 38 that overlaps the membrane electrode assembly 8 when viewed from the direction in which the cathode electrode 12, the membrane 14, and the anode electrode 10 are stacked, the cathode channel 38 feeding / discharging a cathode liquid to / from the cathode electrode 12; and a support member 40 for supporting the membrane electrode assembly 8 so as to inhibit the membrane electrode assembly 8 from fitting into the cathode channel 38.

Description

Organic hydride production equipment

[0001] The present invention relates to an organic hydride manufacturing apparatus.

[0002] In recent years, the use of renewable energy sources such as solar, wind, hydroelectric, and geothermal power has been expected to reduce carbon dioxide emissions during the energy generation process. One example is a system that generates hydrogen by electrolyzing water using electricity derived from renewable energy. Organic hydride systems have also attracted attention as an energy carrier for the large-scale transport and storage of hydrogen derived from renewable energy.

[0003] Conventionally, a known technology for producing organic hydrides includes an organic hydride production apparatus having an anode that generates protons from water, a cathode that hydrogenates an organic compound having an unsaturated bond (a substance to be hydrogenated), and a diaphragm that separates the anode and the cathode (see, for example, Patent Document 1). In this organic hydride production apparatus, water is supplied to the anode, and a substance to be hydrogenated is supplied to the cathode while a current is passed between the anode and the cathode, whereby hydrogen is added to the substance to be hydrogenated, thereby producing an organic hydride.

[0004] International Publication No. 2012 / 091128

[0005] The present inventors have conducted extensive research into organic hydride production techniques and have come to recognize that there is room for improvement in the stability of the electrolysis performance of organic hydride production apparatuses in conventional techniques.

[0006] The present invention has been made in view of the above circumstances, and one of its objects is to provide a technique for improving the stability of the electrolysis performance of an organic hydride manufacturing apparatus.

[0007] One aspect of the present invention is an organic hydride manufacturing apparatus comprising: a membrane electrode assembly in which an anode electrode that oxidizes water in an anolyte to produce protons and a cathode electrode that hydrogenates a substance to be hydrogenated in a catholyte with the protons to produce an organic hydride are stacked with a diaphragm that transfers protons from the anode side to the cathode side, a cathode flow path that overlaps the membrane electrode assembly when viewed in the stacking direction of the cathode electrode, the diaphragm, and the anode electrode and supplies and discharges the catholyte to the cathode electrode, and a support member that supports the membrane electrode assembly so as to prevent the membrane electrode assembly from being embedded in the cathode flow path.

[0008] Any combination of the above components, and conversion of the expression of the present disclosure into a method, device, system, etc., are also valid aspects of the present disclosure.

[0009] According to the present invention, the stability of the electrolysis performance of an organic hydride manufacturing apparatus can be improved.

[0010] Fig. 2 is a schematic diagram of an organic hydride manufacturing system according to an embodiment. Fig. 3 is a cross-sectional view of an organic hydride manufacturing apparatus. Fig. 4 is a cross-sectional view taken along line A-A in Fig. 2. Fig. 5 is a schematic diagram of a membrane electrode assembly and a cathode flow path seen from the stacking direction of electrodes and diaphragms. Fig. 6 is a diagram showing the relationship between current density and toluene concentration at a faradaic efficiency of 95% in each of the organic hydride manufacturing apparatuses of Example 1 and Comparative Example 1.

[0011] The present invention will be described below with reference to the drawings, based on preferred embodiments. The embodiments are merely illustrative and do not limit the technical scope of the present invention. Not all features or combinations thereof described in the embodiments are necessarily essential to the invention. Therefore, many design modifications, such as changes, additions, or deletions of components, are possible within the scope of the invention as defined in the claims. A new embodiment incorporating design modifications will combine the effects of the combined embodiments and modifications. In the embodiments, design modifications that are possible are emphasized by using terms such as "in this embodiment" or "in this embodiment." However, design modifications are also permitted even in areas without such notation. Any combination of the components described in the embodiments is also valid as an aspect of the present invention. Identical or equivalent components, members, and processes shown in each drawing are designated by the same reference numerals, and redundant descriptions are omitted where appropriate. Furthermore, the scale and shape of each part shown in each drawing are set for convenience and should not be construed as limiting unless otherwise specified. Furthermore, when terms such as "first" and "second" are used in this specification or claims, these terms do not represent any order or importance, but are used to distinguish one configuration from another. Furthermore, in each drawing, some members that are not important for explaining the embodiments are omitted.

[0012] 1 is a schematic diagram of an organic hydride production system 1 according to an embodiment. The organic hydride production system 1, as an example, includes an organic hydride production apparatus 2, an anolyte supply device 4, and a catholyte supply device 6.

[0013] The organic hydride production apparatus 2 is an electrolytic cell that hydrogenates a material to be hydrided, which is a dehydrogenated form of organic hydride, through an electrochemical reduction reaction to produce organic hydride. The organic hydride production apparatus 2 includes a membrane electrode assembly 8. The membrane electrode assembly 8 has a structure in which an anode electrode 10 and a cathode electrode 12 are stacked with a diaphragm 14 sandwiched between them. Although only one organic hydride production apparatus 2 is shown in FIG. 1 , the organic hydride production system 1 may include multiple organic hydride production apparatuses 2. In this case, the organic hydride production apparatuses 2 are stacked, for example, with their anode electrodes 10 and cathode electrodes 12 aligned in the same direction. As a result, the organic hydride production apparatuses 2 are electrically connected in series. The organic hydride production apparatuses 2 may be connected in parallel, or a combination of series and parallel connections may be used.

[0014] The anode electrode 10 (anode) oxidizes water in the anolyte LA to generate protons. The anode electrode 10 contains an anode catalyst, such as a metal such as iridium (Ir), ruthenium (Ru), or platinum (Pt), or an oxide of these metals. The anode catalyst may be dispersed and supported on or coated on an electronically conductive substrate. The substrate is composed of a material primarily composed of a metal such as titanium (Ti) or stainless steel (SUS). Examples of the substrate form include a woven or nonwoven sheet, a mesh, a porous sintered body, a foam, and an expanded metal.

[0015] The cathode electrode 12 (negative electrode) hydrogenates the material to be hydrogenated in the cathode fluid LC with protons to produce an organic hydride. The cathode electrode 12 contains, for example, platinum or ruthenium as a cathode catalyst that hydrogenates the material to be hydrogenated. Preferably, the cathode electrode 12 also contains a porous catalyst support that supports the cathode catalyst. The catalyst support is made of an electron-conductive material such as porous carbon, porous metal, or porous metal oxide. The cathode catalyst is also coated with an ionomer (cation-exchange ionomer). For example, the catalyst support supporting the cathode catalyst is coated with the ionomer. Examples of ionomers include perfluorosulfonic acid polymers such as Nafion (registered trademark) and Flemion (registered trademark). Preferably, the ionomer partially coats the cathode catalyst. This allows the three elements (substance to be hydrided, protons, and electrons) necessary for the electrochemical reaction at the cathode electrode 12 to be efficiently supplied to the reaction field.

[0016] The diaphragm 14 is sandwiched between the anode electrode 10 and the cathode electrode 12. The diaphragm 14 in this embodiment is made of a solid polymer electrolyte membrane having proton conductivity, and allows protons to move from the anode electrode 10 side to the cathode electrode 12 side. The solid polymer electrolyte membrane is not particularly limited as long as it is made of a material that conducts protons, and examples thereof include fluorine-based ion exchange membranes having sulfonic acid groups.

[0017] Anode electrode 10 is supplied with anolyte LA by an anolyte supply device 4. The anolyte LA contains water to be supplied to anode electrode 10. Examples of the anolyte LA include an aqueous sulfuric acid solution, an aqueous nitric acid solution, an aqueous hydrochloric acid solution, pure water, and ion-exchanged water.

[0018] A cathode liquid LC is supplied to the cathode electrode 12 by a cathode liquid supply device 6. The cathode liquid LC contains an organic hydride raw material (material to be hydrided) to be supplied to the cathode electrode 12. As an example, the cathode liquid LC does not contain any organic hydride before the organic hydride production system 1 starts operating, and becomes a mixed liquid of the material to be hydrided and the organic hydride as a result of the organic hydride produced by electrolysis being mixed in after the operation starts. The material to be hydrided and the organic hydride are preferably liquids at 20°C and 1 atmosphere.

[0019] The material to be hydrogenated and the organic hydride are not particularly limited as long as they are organic compounds that can add / desorb hydrogen by reversibly causing a hydrogenation reaction / dehydrogenation reaction. The material to be hydrogenated and the organic hydride used in this embodiment can be a wide variety of materials such as acetone-isopropanol, benzoquinone-hydroquinone, and aromatic hydrocarbons. Among these, aromatic hydrocarbons are preferred from the viewpoint of transportability during energy transportation.

[0020] The aromatic hydrocarbon compound used as the compound to be hydrogenated is a compound containing at least one aromatic ring. Examples of aromatic hydrocarbon compounds include benzene, alkylbenzene, naphthalene, alkylnaphthalene, anthracene, diphenylethane, etc. Alkylbenzenes include compounds in which 1 to 4 hydrogen atoms on the aromatic ring are substituted with a linear or branched alkyl group having 1 to 6 carbon atoms. Examples of such compounds include toluene, xylene, mesitylene, ethylbenzene, diethylbenzene, etc. Alkylnaphthalenes include compounds in which 1 to 4 hydrogen atoms on the aromatic ring are substituted with a linear or branched alkyl group having 1 to 6 carbon atoms. Examples of such compounds include methylnaphthalene, etc. These compounds may be used alone or in combination.

[0021] The substance to be hydrogenated is preferably at least one of toluene and benzene. Nitrogen-containing heterocyclic aromatic compounds such as pyridine, pyrimidine, pyrazine, quinoline, isoquinoline, N-alkylpyrrole, N-alkylindole, and N-alkyldibenzopyrrole can also be used as the substance to be hydrogenated. Organic hydrides are the hydrogenated versions of the above-mentioned substances to be hydrogenated, and examples thereof include cyclohexane, methylcyclohexane, dimethylcyclohexane, and piperidine.

[0022] In the organic hydride production apparatus 2, the reaction that occurs when toluene (TL) is used as an example of the substance to be hydrogenated is as follows. When toluene is used as the substance to be hydrogenated, the organic hydride obtained is methylcyclohexane (MCH). <Electrode reaction at the anode electrode> 3H ２ O → 3 / 2O ２ +6H ＋ +6e － <Electrode reaction at the cathode electrode> TL+6H ＋ +6e － →MCH

[0023] That is, the electrode reaction at the anode electrode 10 and the electrode reaction at the cathode electrode 12 proceed in parallel. Protons produced by the electrolysis of water at the anode electrode 10 are supplied to the cathode electrode 12 through the diaphragm 14. Electrons produced by the electrolysis of water are supplied to the cathode electrode 12 through an external circuit. The protons and electrons supplied to the cathode electrode 12 are used to hydrogenate toluene at the cathode electrode 12. As a result, methylcyclohexane is produced.

[0024] Therefore, according to the organic hydride producing system 1 of this embodiment, the electrolysis of water and the hydrogenation reaction of the material to be hydrogenated can be carried out in one step. This improves the efficiency of organic hydride production compared to conventional techniques for producing organic hydrides through a two-stage process consisting of a process for producing hydrogen by water electrolysis or the like and a process for chemically hydrogenating the material to be hydrogenated in a reactor of a plant or the like. Furthermore, since a reactor for chemical hydrogenation and a high-pressure vessel for storing hydrogen produced by water electrolysis or the like are not required, a significant reduction in facility costs can be achieved.

[0025] At the cathode electrode 12, in addition to the main reaction of hydrogenation of the material to be hydrogenated, the side reaction of hydrogen gas generation shown below may occur. As the amount of material to be hydrogenated supplied to the cathode electrode 12 becomes insufficient, this side reaction becomes more likely to occur. <Side reactions that may occur at the cathode electrode> 2H ＋ +2e － →H ２

[0026] Furthermore, when the protons move from the anode electrode 10 side to the cathode electrode 12 side through the diaphragm 14, they move together with water molecules. Therefore, as the electrolytic reduction reaction progresses, water accumulates on the cathode electrode 12 side.

[0027] Electric power is supplied to the organic hydride manufacturing apparatus 2 from an external power source (not shown). When electric power is supplied from the power source to the organic hydride manufacturing apparatus 2, a predetermined electrolytic current is applied between the anode electrode 10 and the cathode electrode 12 of the organic hydride manufacturing apparatus 2, causing the electrolytic current to flow. The power source sends electric power supplied from a power supply device to the organic hydride manufacturing apparatus 2. The power supply device can be configured as a power generation device that generates electric power using renewable energy, such as a wind power generation device or a solar power generation device. Note that the power supply device is not limited to a power generation device that uses renewable energy, and may be a system power source, or a power storage device that stores electric power from a renewable energy power generation device or a system power source. Alternatively, a combination of two or more of these may be used.

[0028] The anode fluid supply device 4 has an anode fluid tank 16, a first anode pipe 18, a second anode pipe 20, and an anode pump 22. The anode fluid tank 16 stores anode fluid LA. The anode fluid tank 16 is connected to the anode electrode 10 by the first anode pipe 18. An anode pump 22 is provided in the first anode pipe 18. The anode pump 22 may be a known pump such as a gear pump or a cylinder pump. The anode fluid supply device 4 may circulate the anode fluid LA using a fluid delivery device other than a pump. The anode fluid tank 16 is also connected to the anode electrode 10 by the second anode pipe 20.

[0029] The anolyte LA in the anolyte tank 16 flows into the anode electrode 10 via the first anode pipe 18 by driving the anode pump 22. The anolyte LA that flows into the anode electrode 10 is used for an electrode reaction at the anode electrode 10. The anolyte LA in the anode electrode 10 is returned to the anolyte tank 16 via the second anode pipe 20. As an example, the anolyte tank 16 also functions as a gas-liquid separator. Oxygen gas is generated by the electrode reaction at the anode electrode 10. Therefore, the anolyte LA discharged from the anode electrode 10 contains oxygen gas. The anolyte tank 16 separates the oxygen gas in the anolyte LA from the anolyte LA and discharges it to the outside of the system.

[0030] The anolyte supply device 4 of the present embodiment circulates the anolyte LA between the anode electrode 10 and the anolyte tank 16. However, the present invention is not limited to this configuration, and the anolyte LA may be sent from the anode electrode 10 to the outside of the system without being returned to the anolyte tank 16.

[0031] The cathode fluid supply device 6 includes a cathode fluid tank 24, a first cathode pipe 26, a second cathode pipe 28, a third cathode pipe 30, a cathode pump 32, and a separation unit 34. The cathode fluid tank 24 stores cathode fluid LC. The cathode fluid tank 24 is connected to the cathode electrode 12 by the first cathode pipe 26. A cathode pump 32 is provided midway along the first cathode pipe 26. The cathode pump 32 may be a known pump such as a gear pump or a cylinder pump. The cathode fluid supply device 6 may circulate the cathode fluid LC using a fluid delivery device other than a pump.

[0032] The separator 34 is connected to the cathode electrode 12 by the second cathode piping 28. The separator 34 includes a known gas-liquid separator and a known oil-water separator. The separator 34 is also connected to the cathode fluid tank 24 by the third cathode piping 30.

[0033] The cathode pump 32 drives the cathode fluid LC in the cathode fluid tank 24 to flow into the cathode electrode 12 via the first cathode pipe 26. The cathode fluid LC that has flowed into the cathode electrode 12 is subjected to an electrode reaction at the cathode electrode 12. The cathode fluid LC in the cathode electrode 12 flows into the separation unit 34 via the second cathode pipe 28. At the cathode electrode 12, hydrogen gas may be generated due to a side reaction. Therefore, the cathode fluid LC discharged from the cathode electrode 12 may contain hydrogen gas. The separation unit 34 separates the hydrogen gas in the cathode fluid LC from the cathode fluid LC and discharges it to the outside of the system. In addition, water moves to the cathode electrode 12 from the anode electrode 10 along with protons. Therefore, the cathode fluid LC discharged from the cathode electrode 12 may contain water. The separator 34 separates the water in the cathode fluid LC from the cathode fluid LC and discharges it to the outside of the system. The cathode fluid LC from which the hydrogen gas and water have been separated is returned to the cathode fluid tank 24 via the third cathode pipe 30.

[0034] The cathode fluid supply device 6 of the present embodiment circulates the cathode fluid LC between the cathode electrode 12 and the cathode fluid tank 24. However, the present invention is not limited to this configuration, and the cathode fluid LC may be sent from the cathode electrode 12 to the outside of the system without being returned to the cathode fluid tank 24.

[0035] Next, the structure of the organic hydride production apparatus 2 will be described in detail. Fig. 2 is a cross-sectional view of the organic hydride production apparatus 2. Fig. 3 is a cross-sectional view taken along line A-A in Fig. 2. Fig. 4 is a schematic diagram of the membrane electrode assembly 8 and the cathode flow path 38 as viewed from the stacking direction of the electrodes and diaphragms. In addition to the membrane electrode assembly 8, the organic hydride production apparatus 2 of this embodiment includes an anode flow path 36 (anode flow path forming structure), a cathode flow path 38 (cathode flow path forming structure), a support member 40, a pair of plate members 42a, 42b, and a gasket 44.

[0036] The plate members 42a and 42b are made of a metal such as stainless steel or titanium. The plate member 42a is stacked on the membrane electrode assembly 8 from the anode electrode 10 side. The plate member 42b is stacked on the membrane electrode assembly 8 from the cathode electrode 12 side. Therefore, the membrane electrode assembly 8 is sandwiched between the pair of plate members 42a and 42b. The gap between the pair of plate members 42a and 42b is sealed with a gasket 44. When the organic hydride production system 1 includes only one organic hydride production apparatus 2, the pair of plate members 42a and 42b may correspond to so-called end plates. When the organic hydride production system 1 includes multiple organic hydride production apparatuses 2 and another organic hydride production apparatus 2 is arranged next to the plate member 42a or the plate member 42b, the plate member may correspond to so-called separators.

[0037] The cathode electrode 12 has a catalyst layer 12a and a diffusion layer 12b. The catalyst layer 12a is disposed closer to the membrane 14 than the diffusion layer 12b. The catalyst layer 12a is in contact with the main surface of the membrane 14. The catalyst layer 12a contains the above-described cathode catalyst, catalyst support, and ionomer. The diffusion layer 12b is in contact with the main surface of the catalyst layer 12a opposite the membrane 14. The diffusion layer 12b uniformly diffuses the catholyte LC supplied from the outside into the catalyst layer 12a. The organic hydride generated in the catalyst layer 12a is discharged to the outside of the cathode electrode 12 via the diffusion layer 12b. The diffusion layer 12b is made of a conductive material such as carbon or metal. The diffusion layer 12b is a porous body such as a sintered body of fibers or particles or a foam molded body. Examples of materials that can be used for the diffusion layer 12b include woven carbon fabric (carbon cloth), nonwoven carbon fabric, and carbon paper. The diffusion layer 12b may be omitted.

[0038] An anode flow path 36 is connected to the anode electrode 10. The anode flow path 36 supplies and discharges the anode fluid LA to and from the anode electrode 10. The plate member 42a of this embodiment has a groove formed on its main surface facing the anode electrode 10. This groove constitutes the anode flow path 36. The anode flow path 36 covers, for example, the entire surface of the anode electrode 10. A first anode pipe 18 and a second anode pipe 20 are connected to the anode flow path 36. As an example, the first anode pipe 18 is connected to the lower end of the anode flow path 36, and the second anode pipe 20 is connected to the upper end of the anode flow path 36. The connection positions of the first anode pipe 18 and the second anode pipe 20 to the anode flow path 36 can be changed as appropriate. By using the groove formed in the plate member 42a as the anode flow path 36, it is possible to prevent an increase in the number of parts and a complication of the assembly process that would otherwise be caused by providing the anode flow path 36.

[0039] A cathode flow path 38 is connected to the cathode electrode 12. The cathode flow path 38 supplies and discharges the cathode fluid LC to and from the cathode electrode 12. The plate member 42b of the present embodiment has a groove formed on its main surface facing the cathode electrode 12. This groove forms the cathode flow path 38. The first cathode piping 26 and the second cathode piping 28 are connected to the cathode flow path 38. By using the groove formed in the plate member 42b as the cathode flow path 38, it is possible to prevent an increase in the number of parts and a complicated assembly process that would otherwise be caused by providing the cathode flow path 38.

[0040] The cathode flow path 38 of this embodiment includes a supply flow path 38a (supply flow path formation structure) that supplies the cathode electrode 12 with the cathode fluid LC, and a recovery flow path 38b (recovery flow path formation structure) that recovers the cathode fluid LC from the cathode electrode 12. As an example, the supply flow path 38a and the recovery flow path 38b each extend in the vertical direction. Note that "extending in the vertical direction" means that one end of a substantially linear flow path is located higher than the other end. Therefore, each flow path may extend obliquely with respect to the horizontal plane. Furthermore, the supply flow path 38a is disposed near one horizontal end of the plate member 42b, and the recovery flow path 38b is disposed near the other horizontal end of the plate member 42b. The first cathode piping 26 is connected to the lower end of the supply flow path 38a, and the second cathode piping 28 is connected to the upper end of the recovery flow path 38b.

[0041] The cathode fluid LC that flows from the first cathode piping 26 into the supply flow path 38a flows from bottom to top within the supply flow path 38a and is delivered to the cathode electrode 12. The cathode fluid LC that flows into the cathode electrode 12 moves within the cathode electrode 12 toward the recovery flow path 38b. The cathode fluid LC that reaches the recovery flow path 38b flows from the cathode electrode 12 into the recovery flow path 38b. The cathode fluid LC then flows from bottom to top within the recovery flow path 38b and is discharged to the second cathode piping 28. The connection positions of the first cathode piping 26 and the second cathode piping 28 to the cathode flow path 38 can be changed as appropriate. For example, the respective pipes may be connected to the side surfaces of the cathode flow path 38 instead of the bottom and top surfaces. The number and arrangement of the supply flow paths 38a and the recovery flow paths 38b can also be changed as appropriate.

[0042] As shown in FIG. 4 , the supply flow path 38a and the recovery flow path 38b are arranged to overlap the membrane electrode assembly 8 when viewed from the stacking direction of the cathode electrode 12, the diaphragm 14, and the anode electrode 10. In general, in an organic hydride production apparatus, high pressure is applied to the membrane electrode assembly to tightly bond the layers together. This increases the efficiency of organic hydride production. The pressure applied to the membrane electrode assembly is greater than that applied to a typical fuel cell. Therefore, if the membrane electrode assembly 8 and the cathode flow path 38 overlap, the membrane electrode assembly 8 may become embedded in the cathode flow path 38. Embedding the membrane electrode assembly 8 in the cathode flow path 38 may increase the pressure loss in the catholyte LC flowing through the cathode flow path 38. Furthermore, if the cathode flow path 38 becomes clogged, the supply of the substance to be hydrided to the cathode electrode 12 may be impeded, and the organic hydride production reaction may stop in at least a portion of the cathode electrode 12. Furthermore, hydrogen is generated as a side reaction, which can reduce the faradaic efficiency during the production of organic hydrides.

[0043] In contrast, the organic hydride manufacturing apparatus 2 of the present embodiment includes a support member 40 that supports the membrane electrode assembly 8 so as to prevent the membrane electrode assembly 8 from being embedded in the cathode flow path 38. This makes it possible to maintain the flow of the cathode fluid LC in the cathode flow path 38. This makes it possible to improve the stability of the electrolysis performance of the organic hydride manufacturing apparatus 2.

[0044] The recovery flow path 38b is located downstream of the flow of the cathode fluid LC relative to the supply flow path 38a, and tends to have a lower internal pressure than the supply flow path 38a. Therefore, the membrane electrode assembly 8 is more easily fitted into the recovery flow path 38b than into the supply flow path 38a. Therefore, it is preferable that the support member 40 be disposed at least in the recovery flow path 38b. In this embodiment, the support member 40 is disposed in both the supply flow path 38a and the recovery flow path 38b. When the cathode pump 32 stops operating and the supply of the cathode fluid LC to the cathode electrode 12 stops, the internal pressure of the supply flow path 38a may also decrease. Therefore, by disposing the support member 40 in both the supply flow path 38a and the recovery flow path 38b, the stability of the electrolysis performance of the organic hydride manufacturing apparatus 2 can be further improved.

[0045] As an example, the support member 40 is an elongated body extending along the cathode flow channel 38 within the cathode flow channel 38. That is, the support member 40 provided in the supply flow channel 38a extends along the supply flow channel 38a, and the support member 40 provided in the recovery flow channel 38b extends along the recovery flow channel 38b. Furthermore, the support member 40 has a curved portion that is convex toward the membrane electrode assembly 8. This can make it easier to prevent the membrane electrode assembly 8 from becoming embedded in the cathode flow channel 38. In this embodiment, the support member 40 is formed of a coil. The coil is made of a metal such as titanium or stainless steel. The coil extends spirally from one end to the other end within each of the supply flow channel 38a and the recovery flow channel 38b, i.e., within the grooves that form each flow channel. This prevents the support member 40 from interfering with the flow of the cathode fluid LC and prevents the membrane electrode assembly 8 from becoming embedded in the cathode flow channel 38.

[0046] (Modifications) The organic hydride manufacturing apparatus 2 according to the above-described embodiment may be modified as follows. That is, although the support member 40 in the embodiment is configured as a coil, this configuration is not particularly limited. For example, the support member 40 may be configured as a stent. The stent is a mesh-like tube. Therefore, the stent has a convex curved portion facing the membrane electrode assembly 8. The stent extends along the cathode flow path 38. The material of the stent is the same as that of the coil. The support member 40 may also be configured as a liquid-permeable porous member such as porous ceramics. The porous member may have a convex curved portion facing the membrane electrode assembly 8, or may be an elongated member extending along the cathode flow path 38. By disposing a stent or a porous member in the cathode flow path 38, it is possible to prevent the membrane electrode assembly 8 from becoming embedded while maintaining the flow of the cathode fluid LC through the cathode flow path 38, as in the case of a coil. The support member 40 may also be provided intermittently in the extension direction of the supply flow path 38a and the recovery flow path 38b.

[0047] The support member 40 may also be configured as a plate material having a plurality of through holes and interposed between the cathode flow path 38 and the membrane electrode assembly 8. Examples of such a plate material include a punched plate and a mesh plate. As an example, the plate material is laminated between the plate member 42b and the diffusion layer 12b. This configuration also makes it possible to prevent the membrane electrode assembly 8 from becoming embedded while maintaining the flow of cathode fluid LC between the cathode flow path 38 and the cathode electrode 12.

[0048] The embodiments may be specified by the following items: [First Item] An organic hydride manufacturing apparatus (2) comprising: an anode electrode (10) that oxidizes water in an anolyte (LA) to produce protons, and a cathode electrode (12) that hydrogenates a substance to be hydrogenated in a catholyte (LC) with the protons to produce an organic hydride, stacked with a diaphragm (14) that transfers protons from the anode electrode (10) side to the cathode electrode (12) side, a cathode flow path (38) that overlaps with the membrane electrode assembly (8) when viewed in the stacking direction of the cathode electrode (12), the diaphragm (14), and the anode electrode (10) and supplies and discharges the catholyte (LC) to the cathode electrode (12), and a support member (40) that supports the membrane electrode assembly (8) so as to prevent the membrane electrode assembly (8) from becoming embedded in the cathode flow path (38). [Item 2] The organic hydride manufacturing apparatus (2) according to Item 1, further comprising a plate member (42b) laminated on the membrane electrode assembly (8), wherein the cathode flow path (38) is formed of a groove provided on the surface of the plate member (42b). [Item 3] The cathode flow path (38) includes a supply flow path (38a) that supplies a cathode liquid (LC) to the cathode electrode (12) and a recovery flow path (38b) that recovers the cathode liquid (LC) from the cathode electrode (12), wherein the support member (40) is disposed in at least the recovery flow path (38b). [Item 4] The organic hydride manufacturing apparatus (2) according to Item 3, wherein the support member (40) is disposed in both the supply flow path (38a) and the recovery flow path (38b). [Item 5] The organic hydride manufacturing apparatus (2) according to any one of Items 1 to 4, wherein the support member (40) is an elongated body extending along the cathode flow path (38) within the cathode flow path (38). [Item 6] The organic hydride manufacturing apparatus (2) according to Item 5, wherein the support member (40) has a convexly curved portion on the membrane electrode assembly (8) side. [Item 7] The organic hydride manufacturing apparatus (2) according to Item 6, wherein the support member (40) is formed as a coil or a stent.[Item 8] The organic hydride manufacturing apparatus (2) according to any one of Items 1 to 6, wherein the support member (40) is composed of a porous member disposed in the cathode flow path (38). [Item 9] The organic hydride manufacturing apparatus (2) according to any one of Items 1 to 4, wherein the support member (40) is composed of a plate material having a plurality of through holes and interposed between the cathode flow path (38) and the membrane electrode assembly (8).

[0049] Examples of the present invention will be described below, but these examples are merely illustrative examples for suitably explaining the present invention and are not intended to limit the present invention in any way.

[0050] Example 1 An organic hydride production apparatus was prepared in which a support member made of a coil was placed in the cathode flow path (both the supply flow path and the recovery flow path). A catholyte with a 100% toluene concentration was circulated through the cathode electrode of this organic hydride production apparatus. An aqueous sulfuric acid solution was circulated as an anolyte through the anode electrode. Then, a current density of 0.6 A / cm was applied. ２ The electrolysis reaction was carried out until the faradaic efficiency, calculated from the amount of by-product hydrogen produced, reached 95%. When the amount of hydrogen produced corresponded to a faradaic efficiency of 95%, the cathode fluid was sampled at the inlet of the cathode flow channel, and the toluene concentration of the cathode fluid was measured using a gas chromatograph.

[0051] The current density was 0.4 A / cm ２ and 0.2 A / cm ２ The electrolysis reaction was also carried out in the same manner as above, and the toluene concentration in the cathode solution at a faradaic efficiency of 95% was measured. The results are shown in Figure 5. These toluene concentrations correspond to the electrolysis performance of the organic hydride production apparatus at the beginning of use. A lower toluene concentration indicates a higher electrolysis performance.

[0052] Subsequently, a cathode solution with a toluene concentration of 18% was supplied to the organic hydride production apparatus of Example 1, and a current density of 0.6 A / cm ２Daily Start and Stop (DSS) operation was carried out for four weeks. Six-hour operation and 18-hour stop periods were alternately repeated during the DSS operation. During the DSS operation, the toluene concentration was maintained at 18% by replenishing the catholyte with toluene and discharging the catholyte. After the DSS operation was completed, the current density was set at 0.6 A / cm. ２ The electrolysis reaction was carried out at 1000 kJ / min, and the toluene concentration in the cathode solution was measured at a faradaic efficiency of 95%. The results are shown in FIG.

[0053] Comparative Example 1 An organic hydride production apparatus having the same configuration as in Example 1 was prepared, except that it did not include a support member. An electrolytic reaction was carried out under the same conditions as in Example 1, and the toluene concentration in the cathode solution at a faradaic efficiency of 95% was measured in the early stages of use of the organic hydride production apparatus. The results are shown in Figure 5. Furthermore, DSS operation was carried out under the same conditions as in Example 1, except that the period was changed to three weeks. After the completion of DSS operation, a current density of 0.6 A / cm was measured. ２ The electrolysis reaction was carried out at 1000 kJ / min, and the toluene concentration in the cathode solution was measured at a faradaic efficiency of 95%. The results are shown in FIG.

[0054] 5 is a graph showing the relationship between current density and toluene concentration at a Faraday efficiency (F efficiency) of 95% in each of the organic hydride production apparatuses of Example 1 and Comparative Example 1. As shown in FIG. 5, there was almost no difference in the initial electrolysis performance between Example 1 and Comparative Example 1. For example, at a current density of 0.6 A / cm ２ The toluene concentration at this time was 12.2% in Example 1 and 13.6% in Comparative Example 1. On the other hand, after DSS operation, the toluene concentration in Comparative Example 1 was 49.5%, and the toluene concentration in Example 1 was 12.5%. In Example 1, although the DSS operation was performed for one week longer than in Comparative Example 1, the initial electrolysis performance was substantially maintained. From the above results, it was confirmed that the stability of the electrolysis performance of the organic hydride manufacturing apparatus can be improved by using the support member to prevent the membrane electrode assembly from getting stuck in the cathode flow path.

[0055] The present invention can be used in an organic hydride manufacturing apparatus.

[0056] 2 organic hydride manufacturing apparatus, 8 membrane electrode assembly, 10 anode electrode, 12 cathode electrode, 14 diaphragm, 38 cathode flow path, 38a supply flow path, 38b recovery flow path, 40 support member, 42b plate member.

Claims

1. a membrane electrode assembly in which an anode electrode that oxidizes water in an anolyte to generate protons and a cathode electrode that hydrogenates a substance to be hydrogenated in a catholyte with the protons to generate an organic hydride are stacked with a diaphragm sandwiched between them that transfers the protons from the anode electrode side to the cathode electrode side; a cathode flow path that overlaps the membrane electrode assembly when viewed from a stacking direction of the cathode electrode, the diaphragm, and the anode electrode, and that supplies and discharges a catholyte to the cathode electrode; a support member that supports the membrane electrode assembly so as to prevent the membrane electrode assembly from being embedded in the cathode flow path. Organic hydride production equipment.

2. a plate member laminated on the membrane electrode assembly, The cathode flow path is formed by a groove provided on the surface of the plate member. The organic hydride manufacturing apparatus according to claim 1 .

3. the cathode flow path includes a supply flow path that supplies a cathode fluid to the cathode electrode and a recovery flow path that recovers the cathode fluid from the cathode electrode; The support member is disposed at least in the recovery flow path.

3. The organic hydride manufacturing apparatus according to claim 1 or 2.

4. The support members are disposed in both the supply flow path and the recovery flow path. The organic hydride manufacturing apparatus according to claim 3 .

5. the support member is an elongated body extending along the cathode flow path within the cathode flow path.

3. The organic hydride manufacturing apparatus according to claim 1 or 2.

6. the support member has a curved portion that is convex toward the membrane electrode assembly. The organic hydride manufacturing apparatus according to claim 5 .

7. The support member is composed of a coil; a stent; or a plate having a plurality of through holes.

3. The organic hydride manufacturing apparatus according to claim 1 or 2.

8. The support member is composed of a porous member disposed in the cathode flow path.

3. The organic hydride manufacturing apparatus according to claim 1 or 2.

9. An organic hydride manufacturing apparatus according to claim 1 or 2, a power supply; a power supply that transmits the power supplied from the power supply device to the organic hydride manufacturing apparatus; Organic hydride production system.

10. The power supply device is configured with at least one of a power generation device that generates power using renewable energy and a system power source. The organic hydride manufacturing system according to claim 9 .

11. The power supply device is composed of both a power generation device that generates power using the renewable energy and the grid power source. The organic hydride production system according to claim 10.