WO2023176197A1

WO2023176197A1 - Organic hydride manufacturing device

Info

Publication number: WO2023176197A1
Application number: PCT/JP2023/004019
Authority: WO
Inventors: 和弘山田
Original assignee: Ｅｎｅｏｓ株式会社
Priority date: 2022-03-17
Filing date: 2023-02-07
Publication date: 2023-09-21

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

The present invention relates to an organic hydride manufacturing apparatus.

In recent years, in order to suppress carbon dioxide emissions during the energy generation process, there are expectations for the use of renewable energy obtained from solar power, wind power, hydropower, geothermal power generation, etc. As an example, a system has been devised that generates hydrogen by electrolyzing water using electricity derived from renewable energy. In addition, organic hydride systems are attracting attention as energy carriers for large-scale transportation and storage of hydrogen derived from renewable energy.

Regarding organic hydride manufacturing technology, conventional organic hydride manufacturing equipment has an anode that generates protons from water, a cathode that hydrogenates an organic compound (hydride) having an unsaturated bond, and a diaphragm that separates the anode and cathode. is known (for example, see Patent Document 1). In this organic hydride production device, by supplying water to the anode and supplying a hydride to the cathode while passing an electric current between the anode and the cathode, hydrogen is added to the hydride and an organic hydride is obtained. .

International Publication No. 2012/091128

As a result of intensive studies on organic hydride manufacturing technology, the present inventors have come to recognize that there is room for improving the stability of electrolytic performance of organic hydride manufacturing equipment in the conventional technology.

The present invention has been made in view of these circumstances, and one of its objectives is to provide a technique for improving the stability of electrolytic performance of an organic hydride production apparatus.

A certain embodiment of the present invention is an organic hydride production apparatus. In this organic hydride production device, an anode electrode that oxidizes water in the anolyte to generate protons, and a cathode electrode that hydrogenates the hydride in the catholyte with protons to generate an organic hydride are connected from the anode side. A membrane electrode assembly stacked with a diaphragm in between that transfers protons to the cathode electrode side, and a cathode that overlaps the membrane electrode assembly when viewed from the stacking direction of the cathode electrode, diaphragm, and anode electrode and supplies and discharges catholyte to the cathode electrode. It includes a flow path and a support member that supports the membrane electrode assembly so as to suppress the membrane electrode assembly from fitting into the cathode flow path.

Arbitrary combinations of the above components and expressions of the present disclosure converted between methods, devices, systems, etc. are also effective as aspects of the present disclosure.

According to the present invention, the stability of electrolytic performance of an organic hydride production apparatus can be improved.

1 is a schematic diagram of an organic hydride production system according to an embodiment. FIG. 1 is a cross-sectional view of an organic hydride manufacturing apparatus. 3 is a sectional view taken along line AA in FIG. 2. FIG. FIG. 2 is a schematic diagram of a membrane electrode assembly and a cathode flow path viewed from the stacking direction of electrodes and diaphragms. FIG. 2 is a diagram showing the relationship between current density and toluene concentration at 95% Faraday efficiency in each organic hydride production apparatus of Example 1 and Comparative Example 1.

Hereinafter, the present invention will be explained based on preferred embodiments with reference to the drawings. The embodiments are illustrative rather than limiting the technical scope of the present invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention. . Therefore, the content of the embodiments may be subject to many design changes, such as changes, additions, and deletions of constituent elements, without departing from the spirit of the invention defined in the claims. A new embodiment with a design change has the effects of each of the combined embodiments and modifications. In the embodiments, contents that allow such design changes are emphasized by adding expressions such as "in this embodiment" or "in this embodiment," but Design changes are also allowed in the content. Any combination of the components described in the embodiments is also effective 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 explanations will be omitted as appropriate. Further, the scale and shape of each part shown in each figure are set for convenience to facilitate explanation, and should not be interpreted in a limited manner unless otherwise mentioned. Furthermore, when terms such as "first" and "second" are used in this specification or the claims, these terms do not indicate any order or importance, and the terms do not indicate any order or degree of importance; This is to distinguish between the two. Further, in each drawing, some members that are not important for explaining the embodiments are omitted.

FIG. 1 is a schematic diagram of an organic hydride production system 1 according to an embodiment. An example organic hydride production system 1 includes an organic hydride production device 2, an anolyte supply device 4, and a catholyte supply device 6.

The organic hydride production apparatus 2 is an electrolytic cell that hydrogenates a hydrogenated substance, which is a dehydrogenated product of an organic hydride, by an electrochemical reduction reaction to produce an 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 in between. Although only one organic hydride manufacturing apparatus 2 is illustrated in FIG. 1, the organic hydride manufacturing system 1 may include a plurality of organic hydride manufacturing apparatuses 2. In this case, each organic hydride production device 2 is stacked with the directions aligned so that, for example, the anode electrode 10 and the cathode electrode 12 are arranged in the same manner. Thereby, each organic hydride manufacturing apparatus 2 is electrically connected in series. Note that the organic hydride manufacturing apparatuses 2 may be connected in parallel, or may be connected in series and connected in parallel.

The anode electrode 10 (anode) oxidizes water in the anolyte LA to generate protons. The anode electrode 10 includes a metal such as iridium (Ir), ruthenium (Ru), platinum (Pt), or an oxide of these metals as an anode catalyst. The anode catalyst may be dispersed and supported on or coated on a substrate having electron conductivity. The base material is made of a material whose main component is a metal such as titanium (Ti) or stainless steel (SUS). Examples of the form of the base material include woven or nonwoven fabric sheets, meshes, porous sintered bodies, foams, expanded metals, and the like.

The cathode electrode 12 (cathode) hydrogenates the hydride in the catholyte LC with protons to generate an organic hydride. The cathode electrode 12 contains, for example, platinum or ruthenium as a cathode catalyst for hydrogenating a substance to be hydrogenated. Preferably, the cathode electrode 12 includes a porous catalyst carrier supporting a cathode catalyst. The catalyst carrier is made of an electronically conductive material such as porous carbon, porous metal, porous metal oxide, or the like. Further, the cathode catalyst is coated with an ionomer (cation exchange type ionomer). For example, a catalyst carrier carrying a cathode catalyst is coated with an ionomer. Examples of the ionomer include perfluorosulfonic acid polymers such as Nafion (registered trademark) and Flemion (registered trademark). Preferably, the ionomer partially covers the cathode catalyst. Thereby, the three elements (hydride, protons, and electrons) required for the electrochemical reaction at the cathode electrode 12 can be efficiently supplied to the reaction field.

The diaphragm 14 is sandwiched between the anode electrode 10 and the cathode electrode 12. The diaphragm 14 of this embodiment is composed of a solid polymer electrolyte membrane having proton conductivity, and moves protons 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 a material that conducts protons, and examples thereof include fluorine-based ion exchange membranes having sulfonic acid groups.

The anode electrode 10 is supplied with the anolyte LA by the anolyte supply device 4. The anolyte LA contains water to be supplied to the anode electrode 10. Examples of the anode solution LA include sulfuric acid aqueous solution, nitric acid aqueous solution, hydrochloric acid aqueous solution, pure water, ion exchange water, and the like.

A catholyte LC is supplied to the cathode electrode 12 by a catholyte supply device 6 . The catholyte LC contains an organic hydride raw material (hydrogenated product) to be supplied to the cathode electrode 12 . As an example, the catholyte LC does not contain any organic hydride before the operation of the organic hydride production system 1 starts, and when the organic hydride generated by electrolysis is mixed in after the start of operation, the catholyte LC becomes a mixed liquid of the hydride and the organic hydride. Become. The hydride and organic hydride are preferably liquid at 20°C and 1 atmosphere.

The hydrogenated product 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/dehydrogenation reaction. As the hydride and organic hydride used in this embodiment, acetone-isopropanol-based, benzoquinone-hydroquinone-based, aromatic hydrocarbon-based, etc. can be widely used. Among these, aromatic hydrocarbons are preferred from the viewpoint of transportability during energy transport.

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

The hydrogenated product is preferably at least one of toluene and benzene. Note that nitrogen-containing heteroaromatic compounds such as pyridine, pyrimidine, pyrazine, quinoline, isoquinoline, N-alkylpyrrole, N-alkylindole, and N-alkyldibenzopyrrole can also be used as the hydrogenated product. The organic hydride is obtained by hydrogenating the above-mentioned hydride, and examples thereof include cyclohexane, methylcyclohexane, dimethylcyclohexane, piperidine, and the like.

The reaction that occurs when toluene (TL) is used as an example of the hydrogenated substance in the organic hydride production apparatus 2 is as follows. When toluene is used as the hydride, the resulting organic hydride 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

That is, the electrode reaction at the anode electrode 10 and the electrode reaction at the cathode electrode 12 proceed in parallel. Protons generated by electrolysis of water at the anode electrode 10 are supplied to the cathode electrode 12 via the diaphragm 14 . Further, electrons generated by water electrolysis are supplied to the cathode electrode 12 via an external circuit. The protons and electrons supplied to the cathode electrode 12 are used for hydrogenation of toluene at the cathode electrode 12. This produces methylcyclohexane.

Therefore, according to the organic hydride production system 1 according to the present embodiment, the electrolysis of water and the hydrogenation reaction of the hydride can be performed in one step. For this reason, the production efficiency of organic hydride is more efficient than the conventional technology, which produces organic hydride through a two-step process of producing hydrogen through water electrolysis, etc., and chemically hydrogenating the substance to be hydrogenated in a reactor such as a plant. can be increased. Furthermore, since a reactor for chemical hydrogenation, a high-pressure container for storing hydrogen produced by water electrolysis, etc. are not required, equipment costs can be significantly reduced.

In the cathode electrode 12, in addition to the main reaction, which is a hydrogenation reaction of the hydride, the following hydrogen gas generation reaction may occur as a side reaction. As the amount of hydride 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

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

Power is supplied to the organic hydride production apparatus 2 from an external power source (not shown). When 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, and the electrolytic current flows. The power source sends power supplied from the power supply device to the organic hydride manufacturing device 2 . The power supply device can be configured with a power generation device that generates 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 grid power source, a renewable energy power generation device, a power storage device that stores power from a grid power source, etc. good. Moreover, a combination of two or more of these may be used.

The anolyte supply device 4 includes an anolyte tank 16, a first anode pipe 18, a second anode pipe 20, and an anode pump 22. The anode solution LA is stored in the anode solution tank 16 . The anolyte tank 16 is connected to the anode electrode 10 by a first anode pipe 18 . An anode pump 22 is provided in the middle of the first anode pipe 18 . The anode pump 22 can be configured with a known pump such as a gear pump or a cylinder pump. Note that the anolyte supply device 4 may circulate the anolyte LA using a liquid feeding device other than a pump. The anolyte tank 16 is also connected to the anode electrode 10 by a second anode pipe 20 .

The anode solution LA in the anode solution tank 16 flows into the anode electrode 10 via the first anode pipe 18 by driving the anode pump 22 . The anolyte LA that has flowed into the anode electrode 10 is subjected to 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 anode liquid tank 16 also functions as a gas-liquid separation section. Oxygen gas is generated at the anode electrode 10 by an electrode reaction. Therefore, the anolyte LA discharged from the anode electrode 10 contains oxygen gas. The anolyte tank 16 separates the oxygen gas in the anode solution LA from the anode solution LA and discharges it to the outside of the system.

The anolyte supply device 4 of this embodiment circulates the anolyte LA between the anode electrode 10 and the anolyte tank 16. However, the configuration is not limited to this, and a configuration may be adopted in which the anolyte LA is sent out of the system from the anode electrode 10 without returning to the anolyte tank 16.

The catholyte supply device 6 includes a catholyte tank 24, a first cathode pipe 26, a second cathode pipe 28, a third cathode pipe 30, a cathode pump 32, and a separation section 34. The catholyte tank 24 stores catholyte LC. The catholyte tank 24 is connected to the cathode electrode 12 by a first cathode pipe 26 . A cathode pump 32 is provided in the middle of the first cathode pipe 26 . The cathode pump 32 can be configured with a known pump such as a gear pump or a cylinder pump. Note that the catholyte supply device 6 may circulate the catholyte LC using a liquid sending device other than a pump.

The separation section 34 is connected to the cathode electrode 12 by a second cathode pipe 28. The separation section 34 includes a known gas-liquid separator and a known oil-water separator. Further, the separation section 34 is connected to the catholyte tank 24 by a third cathode pipe 30.

The catholyte LC in the catholyte tank 24 flows into the cathode electrode 12 via the first cathode pipe 26 by driving the cathode pump 32 . The catholyte LC that has flowed into the cathode electrode 12 is subjected to an electrode reaction at the cathode electrode 12 . The catholyte LC in the cathode electrode 12 flows into the separation section 34 via the second cathode pipe 28 . At the cathode electrode 12, hydrogen gas may be generated due to side reactions. Therefore, the catholyte LC discharged from the cathode electrode 12 may contain hydrogen gas. The separation unit 34 separates the hydrogen gas in the catholyte LC from the catholyte LC and discharges it out of the system. Furthermore, water moves from the anode electrode 10 to the cathode electrode 12 together with protons. Therefore, the catholyte LC discharged from the cathode electrode 12 may contain water. The separation unit 34 separates water in the catholyte LC from the catholyte LC and discharges the water to the outside of the system. The catholyte LC from which hydrogen gas and water have been separated is returned to the catholyte tank 24 via the third cathode pipe 30 .

The catholyte supply device 6 of this embodiment circulates the catholyte LC between the cathode electrode 12 and the catholyte tank 24. However, the configuration is not limited to this, and a configuration may be adopted in which the catholyte LC is sent out of the system from the cathode electrode 12 without returning to the catholyte tank 24.

Next, the structure of the organic hydride manufacturing apparatus 2 will be explained in detail. FIG. 2 is a sectional view of the organic hydride manufacturing apparatus 2. As shown in FIG. FIG. 3 is a cross-sectional view taken along line AA in FIG. FIG. 4 is a schematic diagram of the membrane electrode assembly 8 and the cathode channel 38 as seen from the stacking direction of the electrodes and the diaphragm. The organic hydride manufacturing apparatus 2 of this embodiment includes, in addition to the membrane electrode assembly 8, an anode channel 36 (anode channel forming structure), a cathode channel 38 (cathode channel forming structure), and a support member 40. , a pair of

plate members

42a and 42b, and a gasket 44.

The plate member 42a and the plate member 42b are made of 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 laminated 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. A 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 a plurality of 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 a so-called separator.

The cathode electrode 12 has a catalyst layer 12a and a diffusion layer 12b. The catalyst layer 12a is arranged closer to the diaphragm 14 than the diffusion layer 12b. The catalyst layer 12a is in contact with the main surface of the diaphragm 14. The catalyst layer 12a contains the above-mentioned cathode catalyst, catalyst carrier, and ionomer. The diffusion layer 12b is in contact with the main surface of the catalyst layer 12a on the side opposite to the diaphragm 14. The diffusion layer 12b uniformly diffuses the catholyte LC supplied from the outside into the catalyst layer 12a. Further, 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. Further, the diffusion layer 12b is a porous body such as a sintered body of fibers or particles, or a foam molded body. Examples of the material constituting the diffusion layer 12b include carbon woven cloth (carbon cloth), carbon nonwoven cloth, carbon paper, and the like. Note that the diffusion layer 12b may be omitted in some cases.

An anode channel 36 is connected to the anode electrode 10. The anode flow path 36 supplies and discharges the anode liquid LA to and from the anode electrode 10 . The plate member 42a of this embodiment is provided with a groove on its main surface facing the anode electrode 10 side. This groove constitutes an anode flow path 36. The anode channel 36 covers the entire surface of the anode electrode 10, for example. The first anode pipe 18 and the 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 with respect to the anode flow path 36 can be changed as appropriate. By using the groove provided in the plate member 42a as the anode flow path 36, it is possible to suppress an increase in the number of parts and complication of the assembly process due to the provision of the anode flow path 36.

A cathode channel 38 is connected to the cathode electrode 12. The cathode channel 38 supplies and discharges the catholyte LC to and from the cathode electrode 12 . The plate member 42b of this embodiment is provided with a groove on its main surface facing the cathode electrode 12 side. This groove constitutes a cathode flow path 38. The first cathode pipe 26 and the second cathode pipe 28 are connected to the cathode flow path 38 . By using the groove provided in the plate member 42b as the cathode flow path 38, it is possible to suppress an increase in the number of parts and a complicated assembly process due to the provision of the cathode flow path 38.

The cathode channel 38 of this embodiment includes a supply channel 38a (supply channel forming structure) that supplies catholyte LC to the cathode electrode 12, and a recovery channel 38b (recovery channel 38b) that recovers catholyte LC from the cathode electrode 12. flow path forming structure). As an example, the supply channel 38a and the recovery channel 38b each extend in the vertical direction. Note that "extending in the vertical direction" means that one end of the substantially linear channel is located above the other end. Therefore, each channel may extend obliquely to the horizontal plane. Further, the supply channel 38a is arranged near one end of the plate member 42b in the horizontal direction, and the recovery channel 38b is arranged near the other end of the plate member 42b in the horizontal direction. The first cathode pipe 26 is connected to the lower end of the supply channel 38a, and the second cathode pipe 28 is connected to the upper end of the recovery channel 38b.

The catholyte LC that has flowed into the supply channel 38 a from the first cathode pipe 26 flows from the bottom to the top in the supply channel 38 a and is sent to the cathode electrode 12 . The catholyte LC that has flowed into the cathode electrode 12 moves within the cathode electrode 12 toward the recovery channel 38b. The catholyte LC that has reached the recovery channel 38b flows from the cathode electrode 12 into the recovery channel 38b. Then, the catholyte LC flows from the bottom to the top in the recovery channel 38b and is discharged into the second cathode pipe 28. Note that the connection positions of the first cathode pipe 26 and the second cathode pipe 28 with respect to the cathode flow path 38 can be changed as appropriate. For example, each pipe may be connected to the side surface of the cathode channel 38 instead of the bottom and top surface. Further, the number and arrangement of the supply channel 38a and the recovery channel 38b can also be changed as appropriate.

As shown in FIG. 4, the supply channel 38a and the recovery channel 38b are arranged so as 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. Generally, in an organic hydride manufacturing apparatus, high pressure is applied to the membrane electrode assembly to bring the layers into close contact with each other. Thereby, the production efficiency of organic hydride can be improved. The pressure applied to the membrane electrode assembly is greater than the pressure applied to a typical fuel cell. Therefore, if the membrane electrode assembly 8 and the cathode channel 38 overlap, the membrane electrode assembly 8 can fit into the cathode channel 38 . When the membrane electrode assembly 8 fits into the cathode channel 38, the pressure loss occurring in the catholyte LC flowing through the cathode channel 38 may increase. Furthermore, the cathode flow path 38 is blocked and the supply of the hydride to the cathode electrode 12 is delayed, and the reaction for producing organic hydride in at least a portion of the cathode electrode 12 may be stopped. Furthermore, hydrogen is generated due to side reactions, which may reduce faradaic efficiency during the production of organic hydride.

In contrast, the organic hydride production apparatus 2 of the present embodiment includes a support member 40 that supports the membrane electrode assembly 8 so as to suppress the membrane electrode assembly 8 from fitting into the cathode channel 38. Thereby, the circulation of the catholyte LC in the cathode channel 38 can be maintained. Therefore, the stability of the electrolytic performance of the organic hydride production apparatus 2 can be improved.

The recovery channel 38b is located on the downstream side of the flow of the catholyte LC than the supply channel 38a, and tends to have a lower internal pressure than the supply channel 38a. Therefore, the membrane electrode assembly 8 can fit into the recovery channel 38b more easily than the supply channel 38a. Therefore, it is preferable that the support member 40 is disposed at least in the recovery channel 38b. In this embodiment, support members 40 are arranged in both the supply channel 38a and the recovery channel 38b. When the driving of the cathode pump 32 is stopped and the supply of the catholyte liquid LC to the cathode electrode 12 is stopped, the internal pressure of the supply channel 38a may also decrease. Therefore, by arranging the support member 40 in both the supply channel 38a and the recovery channel 38b, the stability of the electrolytic performance of the organic hydride production apparatus 2 can be further improved.

The support member 40 as an example is an elongated body that extends within the cathode flow path 38 and along the cathode flow path 38 . That is, the support member 40 provided in the supply flow path 38a extends along the supply flow path 38a, and the support member 40 provided in the recovery flow path 38b extends along the recovery flow path 38b. Further, the support member 40 has a convex curved portion on the membrane electrode assembly 8 side. With these, it is possible to easily prevent the membrane electrode assembly 8 from fitting into the cathode channel 38. The support member 40 of this embodiment is composed of a coil. The coil is made of metal such as titanium or stainless steel. The coil extends spirally from one end to the other end inside each of the supply channel 38a and the recovery channel 38b, that is, inside the grooves forming each channel. Thereby, it is possible to prevent the membrane electrode assembly 8 from fitting into the cathode channel 38 while preventing the support member 40 from inhibiting the flow of the catholyte LC.

(Modified example)
The following modification examples can be given to the organic hydride manufacturing apparatus 2 according to the embodiment described above. That is, although the support member 40 of the embodiment is composed of a coil, it is not particularly limited to this configuration. For example, support member 40 may be comprised of a stent. A stent is a mesh tube. Therefore, the stent has a convex curved portion on the membrane electrode assembly 8 side. The stent also extends along cathode channel 38. The material of the stent is the same as that of the coil. Further, the support member 40 may be made of a porous member having liquid permeability, such as porous ceramics. The porous member may have a convex curved portion on the membrane electrode assembly 8 side, or may be a long body extending along the cathode channel 38. By arranging a stent or a porous member in the cathode channel 38, as in the case of a coil, it is possible to suppress the insertion of the membrane electrode assembly 8 while maintaining the flow of the catholyte LC in the cathode channel 38. I can do it. Note that the support member 40 may be provided intermittently in the extending direction of the supply channel 38a and the recovery channel 38b.

Further, the support member 40 may be interposed between the cathode channel 38 and the membrane electrode assembly 8 and may be composed of a plate material having a plurality of through holes. 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. Also in this embodiment, it is possible to prevent the membrane electrode assembly 8 from getting stuck while maintaining the flow of the catholyte LC between the cathode channel 38 and the cathode electrode 12.

Embodiments may be specified by the items described below.
[First item]
An anode electrode (10) that oxidizes water in an anolyte (LA) to generate protons, and a cathode electrode (12) that hydrogenates a hydride in a catholyte (LC) with protons to generate an organic hydride. , a membrane electrode assembly (8) laminated with a diaphragm (14) that moves protons from the anode electrode (10) side to the cathode electrode (12) side;
A cathode channel (seeing from the lamination direction of the cathode electrode (12), diaphragm (14), and anode electrode (10) that overlaps the membrane electrode assembly (8) and supplies and discharges catholyte liquid (LC) to and from the cathode electrode (12) 38) and
a support member (40) that supports the membrane electrode assembly (8) so as to suppress the membrane electrode assembly (8) from fitting into the cathode channel (38);
Organic hydride production equipment (2).
[Second item]
comprising a plate member (42b) laminated on the membrane electrode assembly (8),
The cathode channel (38) is composed of a groove provided on the surface of the plate member (42b).
The organic hydride production apparatus (2) according to the first item.
[Third item]
The cathode channel (38) includes a supply channel (38a) that supplies catholyte (LC) to the cathode electrode (12), and a recovery channel (38b) that collects catholyte (LC) from the cathode electrode (12). and,
The support member (40) is arranged at least in the recovery channel (38b).
The organic hydride production apparatus (2) according to the first item or the second item.
[4th item]
The support member (40) is arranged in both the supply channel (38a) and the recovery channel (38b),
The organic hydride production apparatus (2) according to the third item.
[Item 5]
The support member (40) is an elongated body that extends within the cathode flow path (38) and along the cathode flow path (38).
The organic hydride production apparatus (2) according to any one of the first to fourth items.
[Item 6]
The support member (40) has a convex curved portion on the membrane electrode assembly (8) side.
The organic hydride production apparatus (2) according to item 5.
[Item 7]
The support member (40) is comprised of a coil or a stent.
The organic hydride production apparatus (2) according to item 6.
[Item 8]
The support member (40) is composed of a porous member disposed within the cathode channel (38).
The organic hydride manufacturing apparatus (2) according to any one of the first to sixth items.
[Item 9]
The support member (40) is interposed between the cathode channel (38) and the membrane electrode assembly (8) and is composed of a plate material having a plurality of through holes.
The organic hydride production apparatus (2) according to any one of the first to fourth items.

Examples of the present invention will be described below, but the examples are merely illustrative to suitably explain the present invention, and are not intended to limit the present invention in any way.

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

Electrolytic reactions were carried out in the same manner when the current density was 0.4 A/cm ² and 0.2 A/cm ² , and the toluene concentration of the catholyte when the Faraday efficiency was 95% was measured. The results are shown in Figure 5. These toluene concentrations correspond to the electrolytic performance at the initial stage of use of the organic hydride production apparatus. The lower the toluene concentration, the higher the electrolytic performance.

Subsequently, a catholyte having a toluene concentration of 18% was supplied to the organic hydride production apparatus of Example 1, and DSS (Daily Start and Stop) operation was performed for 4 weeks at a current density of 0.6 A/cm ² . In the DSS operation, 6 hours of operation and 18 hours of stopping were repeated alternately. 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, an electrolytic reaction was carried out at a current density of 0.6 A/cm ² , and the toluene concentration of the catholyte at a Faraday efficiency of 95% was measured. The results are shown in Figure 5.

(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. Then, an electrolytic reaction was carried out under the same conditions as in Example 1, and the toluene concentration of the catholyte was measured when the Faraday efficiency was 95% at the beginning of use of the organic hydride production apparatus. The results are shown in Figure 5. Further, DSS operation was carried out under the same conditions as in Example 1, except that the period was 3 weeks. After completion of the DSS operation, an electrolytic reaction was carried out at a current density of 0.6 A/cm ² , and the toluene concentration of the catholyte at a Faraday efficiency of 95% was measured. The results are shown in Figure 5.

FIG. 5 is a diagram showing the relationship between current density and toluene concentration when Faraday efficiency (F efficiency) is 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 initial electrolytic performance between Example 1 and Comparative Example 1. For example, the toluene concentration at a current density of 0.6 A/cm ² was 12.2% in Example 1 and 13.6% in Comparative Example 1. On the other hand, after implementation of the 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 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 electrolytic performance of the organic hydride production apparatus can be improved by suppressing the insertion of the membrane electrode assembly into the cathode channel using the support member.

The present invention can be utilized in an organic hydride manufacturing device.

2 Organic hydride manufacturing device, 8 Membrane electrode assembly, 10 Anode electrode, 12 Cathode electrode, 14 Diaphragm, 38 Cathode channel, 38a Supply channel, 38b Recovery channel, 40 Support member, 42b Plate member.

Claims

An anode electrode that oxidizes water in the anolyte to generate protons, and a cathode electrode that hydrogenates a hydride in the catholyte with the protons to generate an organic hydride, from the anode side to the cathode side. A membrane electrode assembly stacked with a diaphragm for transferring the protons sandwiched therebetween;
a cathode channel that overlaps the membrane electrode assembly when viewed from the stacking direction of the cathode electrode, the diaphragm, and the anode electrode, and supplies and discharges catholyte to and from the cathode electrode;
a support member that supports the membrane electrode assembly so as to suppress the membrane electrode assembly from fitting into the cathode flow path;
Organic hydride production equipment.
comprising a plate member laminated on the membrane electrode assembly,
The cathode flow path is constituted by a groove provided on the surface of the plate member.
The organic hydride production apparatus according to claim 1.
The cathode channel includes a supply channel that supplies catholyte to the cathode electrode, and a recovery channel that collects catholyte from the cathode electrode,
the support member is disposed at least in the recovery channel;
The organic hydride production apparatus according to claim 1 or 2.
The support member is arranged in both the supply channel and the recovery channel,
The organic hydride production apparatus according to claim 3.
The support member is an elongated body that extends within the cathode flow path along the cathode flow path.
The organic hydride production apparatus according to any one of claims 1 to 4.
The support member has a curved portion that is convex toward the membrane electrode assembly.
The organic hydride production apparatus according to claim 5.
The support member is composed of a coil or a stent.
The organic hydride production apparatus according to claim 6.
The support member is composed of a porous member disposed within the cathode flow path.
The organic hydride production apparatus according to any one of claims 1 to 6.
The support member is comprised of a plate material interposed between the cathode channel and the membrane electrode assembly and having a plurality of through holes.
The organic hydride production apparatus according to any one of claims 1 to 4.