Ammonia production equipment

Abstract

Provided is an ammonia production apparatus comprising: a first electrolytic cell in which at least a portion of a first electrolytic medium is housed; a first electrode disposed in the first electrolytic cell; a second electrolytic cell in which at least a portion of a second electrolytic medium is housed; a second electrode disposed in the second electrolytic cell; a separator provided between the first electrolytic cell and the second electrolytic cell; and a first separation part separating ammonia from the second electrolytic medium. The first electrolytic cell is configured such that a proton source contained in the first electrolytic medium is oxidized at the first electrode, protons are generated, and, in the second electrolytic medium, ammonia and hydrogen are generated from nitrogen, protons, and electrons in the presence of a nitrogen activation catalyst. The first separation part is configured such that nitrogen and hydrogen that have been separated from the ammonia are supplied to the first electrolytic medium.

Description

[Technical Field]

[0001] This invention relates to an ammonia production apparatus. [Background technology]

[0002] The Haber-Bosch process, which synthesizes ammonia by reacting hydrogen and nitrogen, is a well-known and representative method for producing ammonia. However, because the Haber-Bosch process produces ammonia under high temperature and pressure, it requires a large amount of energy. In contrast, in recent years, ammonia production methods that can produce ammonia under milder conditions have been developed.

[0003] For example, Patent Document 1 discloses an ammonia production apparatus that is inexpensive and allows for reaction control, comprising: a first electrolytic cell for containing a first electrolyte; an oxidizing electrode disposed in the first electrolytic cell; a second electrolytic cell for containing a second electrolyte containing nitrogen, an ammonia generation catalyst, and a reducing agent; a reducing electrode disposed in the second electrolytic cell; an electrochemical reaction unit equipped with a diaphragm 4, configured to produce ammonia by reducing nitrogen in the second electrolytic cell with the ammonia generation catalyst and reducing agent, and to reduce the reducing agent oxidized by the produced ammonia by connecting the oxidizing electrode and the reducing electrode to a power source; a nitrogen supply unit equipped with a nitrogen supply section for dissolving nitrogen in the second electrolyte; and an ammonia separation unit equipped with a separation section for separating ammonia from the second electrolyte containing ammonia. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2021 / 124616 [Overview of the project] [Problems that the invention aims to solve]

[0005] The above ammonia production method had a problem in that unreacted nitrogen and by-product hydrogen after separating the produced ammonia could not be effectively utilized. Patent Document 1 above does not disclose anything about the removal of by-product hydrogen and only discloses removing hydrogen and nitrogen outside the system and recycling only the electrolytic solution.

[0006] An object of the present invention is to solve the above problems, and an object is to provide an ammonia production apparatus capable of effectively utilizing unreacted nitrogen and by-product hydrogen.

Means for Solving the Problems

[0007] The present invention includes the following aspects. [1] A first electrolytic cell containing at least a part of a first electrolytic medium, A first electrode disposed in the first electrolytic cell, A second electrolytic cell containing at least a part of a second electrolytic medium, A second electrode disposed in the second electrolytic cell, A separator provided between the first electrolytic cell and the second electrolytic cell, An ammonia production apparatus including a first separation unit that separates ammonia from the second electrolytic medium, wherein In the first electrolytic cell, a proton source contained in the first electrolytic medium is oxidized at the first electrode to generate protons, In the second electrolytic medium, ammonia and hydrogen are generated from nitrogen, protons, and electrons in the presence of a nitrogen activation catalyst, The ammonia production apparatus is configured such that nitrogen and hydrogen after the first separation unit separates ammonia are supplied to the first electrolytic medium. [2] Further including a second separation unit that separates nitrogen from the first electrolytic medium, The ammonia production apparatus according to [1], wherein nitrogen separated by the second separation unit is supplied to the second electrolytic medium. [3] In the second electrolytic cell, nitrogen, electrons, and protons that react in the presence of the nitrogen activation catalyst, (i-1) Protons supplied from the proton source of the first electrolytic cell through the separator, (i-2) Protons supplied through the proton mediator contained in the second electrolytic cell, and (i-3) Protons supplied through the reducing agent contained in the second electrolytic cell The ammonia production apparatus according to [1] or [2], which is at least one of them. [4] In the second electrolytic cell, electrons that react with nitrogen and protons in the presence of the nitrogen activation catalyst are (ii-1) Electrons supplied from the second electrode, (ii-2) Electrons supplied through the electron mediator contained in the second electrolytic cell, and (ii-3) Electrons supplied through the reducing agent contained in the second electrolytic cell The ammonia production apparatus according to any one of [1] to [3], which is at least one of them. [5] The ammonia production apparatus according to any one of [1] to [4], wherein the proton source is water. [6] The ammonia production apparatus according to [5], further comprising a nitrogen supply device for supplying nitrogen to the second electrolytic medium, The nitrogen supply device includes a second separation unit that supplies air to separate nitrogen and oxygen, and is configured to supply oxygen and nitrogen discharged from the first electrolytic cell to the nitrogen supply device. [7] The ammonia production apparatus according to any one of [1] to [6], wherein the second electrolytic medium is an electrolytic solution.

Advantages of the Invention

[0008] The ammonia production apparatus of the present invention provides an ammonia production apparatus that can solve the above problems. In addition, in order to effectively utilize unreacted nitrogen and by-product hydrogen, it usually requires a great deal of energy and also requires complex device configurations such as cryogenic separation and pressure swing adsorption devices. However, according to the present invention, such devices are not required and the above problems can be solved.

Brief Description of the Drawings

[0009] [Figure 1] This diagram schematically shows the main parts of the ammonia production apparatus 1 according to the present invention. [Figure 2] This figure illustrates the reaction scheme of the ammonia production reaction in the ammonia production apparatus 1 according to the present invention. [Figure 3] This figure schematically shows an ammonia production apparatus 1 according to a preferred embodiment of the present invention. [Figure 4] This figure schematically shows an ammonia production apparatus 1 according to a preferred embodiment of the present invention. [Modes for carrying out the invention]

[0010] The ammonia production apparatus according to the present invention will be described below. The embodiments described below are not intended to limit the invention as defined in the claims. Furthermore, not all of the elements and combinations thereof described in the embodiments are necessarily essential to the present invention.

[0011] Figure 1 is a schematic diagram showing the main parts of the ammonia production apparatus 1 according to Embodiment 1. Figure 2 is a diagram illustrating the reaction scheme of the ammonia production reaction in the ammonia production apparatus 1 according to Embodiment 1. Figures 3 and 4 are schematic diagrams showing the ammonia production apparatus 1 according to a preferred embodiment. The ammonia production apparatus according to Embodiment 1 will be described below with reference to Figures 1 to 4.

[0012] The ammonia production apparatus 1 comprises a first electrolytic cell 10, a first electrode 12 located in the first electrolytic cell 10, a second electrolytic cell 30, a second electrode 32 located in the second electrolytic cell 30, and a separator 60 provided between the first electrolytic cell 10 and the second electrolytic cell 30. In the following explanation, the first electrolytic cell 10 and the first electrode 12 may be referred to as the "anode," and the second electrolytic cell 30 and the second electrode 32 may be referred to as the "cathode."

[0013] The first electrolytic cell 10 contains at least a portion of the first electrolytic medium 20. The first electrolytic medium 20 may be, for example, a liquid electrolyte, the first electrolyte 21, but the first electrolytic medium 20 is not limited to a liquid electrolyte. A gas containing a proton source, such as water vapor or hydrogen gas, can also be used as the first electrolytic medium 20. In the following description, the case in which the first electrolyte 21 is used as the first electrolytic medium 20 will be described as an example.

[0014] The second electrolytic cell 30 contains at least a portion of the second electrolytic medium 40. The second electrolytic medium 40 may be, for example, a liquid electrolyte, the second electrolyte 41, but the second electrolytic medium 40 is not limited to a liquid electrolyte. The second electrolytic medium 40 can also be made using only nitrogen as a raw material and a gas such as ammonia as a product, without using a liquid such as an electrolyte. In the following explanation, the case in which the second electrolyte 41 is used as the second electrolytic medium 40 will be explained as an example. The first electrolyte 21 and the second electrolyte 41 will be explained in detail later.

[0015] The first electrode 12 is connected to the anode (positive electrode) of an external power supply (not shown). Examples of materials that make up the first electrode 12 include those mainly composed of carbon fibers, such as carbon fiber nonwoven fabric (carbon felt) or paper, as well as titanium fiber nonwoven fabric mainly composed of titanium fibers, and nonwoven fabrics in which different metals are supported on the fibers. In addition, any material can be used to make up the first electrode 12 as long as it is capable of exchanging electrons with the components contained in the first electrolyte 21.

[0016] The second electrode 32 is connected to the cathode (negative electrode) of an external power supply (not shown). Examples of materials that make up the second electrode 32 include those mainly composed of carbon fibers, such as carbon fiber nonwoven fabric (carbon felt) or paper, as well as titanium fiber nonwoven fabric mainly composed of titanium fibers, and nonwoven fabrics in which different metals are supported on the fibers. Furthermore, any material can be used to make up the second electrode 32 as long as it is capable of exchanging electrons with the components contained in the second electrolyte 41. In addition, the material that makes up the first electrode 12 and the material that makes up the second electrode 32 may be the same material or different materials.

[0017] The separator 60 is a membrane that separates the first electrolytic cell 10 and the second electrolytic cell 30, and is a membrane that allows cations to flow selectively. As the separator 60, commercially available solid electrolyte membranes such as Nafion 117 (DuPont, "Nafion" is a registered trademark), Nafion 212 (DuPont, "Nafion" is a registered trademark), LICGC AG-01 (Ohara, "LICGC" is a registered trademark), Aquivion E98-05E (Solvay, "Aquivion" is a registered trademark), and Celemion ASP4 (AGC Engineering, "Celemion" is a registered trademark) can be used, or a solid electrolyte membrane manufactured using Nafion dispersion (DuPont, "Nafion" is a registered trademark) can be used. In addition, the above-mentioned solid electrolyte membrane may be used in which multiple membranes are pressed together by methods such as hot pressing.

[0018] In the first electrolytic cell 10, the proton source contained in (supplied) the first electrolyte 21 is oxidized, and protons are generated. That is, as shown in Figure 1, the proton source contained in the first electrolyte 21 is configured to generate protons by releasing electrons to the first electrode 12.

[0019] If the proton source is, for example, water (H2O), the oxidation reaction shown in the following reaction equation occurs in the first electrolytic cell 10, and protons are generated from water.

[0020] [Number]

[0021] In the first electrode, in order to cause the above reaction, there is no particular limitation, but catalysts such as Ir, Ru, IrO (x = 1 to 3), RuO x (x = 1 to 3), NiO x (x = 1 to 1.5), CoO x (x = 1 to 1.5), FeO x (x = 1 to 1.5), FeOOH, CoPO x (x = 1 to 1.5), NiMo, NiCr, etc. may be used.

[0022] On the other hand, when the proton source is, for example, hydrogen (H2), in the first electrolytic cell 10, an oxidation reaction shown by the following reaction formula occurs, and protons are generated from hydrogen.

[0023] [Number]

[0024] In the above case, in the first electrode, in order to cause the above reaction, there is no particular limitation, but catalysts such as Pt, PtRu, Pd, Ir, IrPd, IrMo, RuIr, NiMo, NiW, NiCu, etc. may be used.

[0025] In this embodiment, water may be used as the proton source, and hydrogen contained in the mixed gas B described later may also be used as the proton source. In that case, the first electrode is a catalyst (for example, Ir, Ru, IrO x (x = 1 to 3), RuO x [[ID=4​​​​​​​It is preferable to include both a catalyst (at least one selected from the group consisting of (x=1~1.5), NiMo, and NiCr) and a catalyst that drives the oxidation reaction when the above-mentioned proton source is hydrogen (for example, at least one selected from the group consisting of Pt, PtRu, Pd, Ir, IrPd, IrMo, RuIr, NiMo, NiW, and NiCu).

[0026] Alternatively, the first electrolytic cell using water as the proton source and the first electrolytic cell using hydrogen as the proton source can be installed separately.

[0027] The ammonia production apparatus 1 is configured to produce ammonia and hydrogen by the reaction of nitrogen, protons, and electrons in a second electrolytic medium 40 in the presence of a nitrogen-activated catalyst.

[0028] The nitrogen-activated catalyst serves as the reaction field and may be contained in the second electrolytic medium 40, or it may be fixed and housed in the second electrolytic cell 30.

[0029] The nitrogen activation catalyst is not particularly limited as long as it is a catalyst that can activate nitrogen. Examples include metal complexes that activate nitrogen, preferably organometallic complexes that can cleave nitrogen triple bonds, and more preferably organometallic complexes that can cleave nitrogen triple bonds and are soluble in organic solvents. Here, "soluble in organic solvents" means, for example, that the nitrogen activation catalyst can be mixed with an organic solvent in an amount that results in a concentration of 0.1 mmol / L and its dissolution can be confirmed visually.

[0030] Examples of the central metal of the nitrogen-activating metal complex include Ti, V, Mo, Fe, Mn, Co, Pt, Ir, and W, with Mo being preferred.

[0031] Examples of ligands for the nitrogen-activating metal complex include halide ions and tertiary phosphines. Preferably, the combination is a pincer ligand (i.e., a ligand in which three coordinating atoms are bonded from three directions on the same plane including the central metal) and a halide ion. More preferably, the combination is a PCP (phosphorus-carbon-phosphorus) type pincer ligand or a PNP (phosphorus-nitrogen-phosphorus) type pincer ligand and a halide ion. Even more preferably, the combination is a PCP type pincer ligand and a halide ion. As the metal complex that activates nitrogen, a complex that is suitable for its solubility in organic solvents and reactivity with reducing agents can be suitably used.

[0032] Among these, molybdenum complexes with Mo as the central metal are preferred as metal complexes that activate nitrogen, molybdenum complexes having pincer ligands as ligands are more preferred, molybdenum complexes having PCP-type pincer ligands or PNP-type pincer ligands as ligands are even more preferred, and molybdenum complexes having PCP-type pincer ligands as ligands are even more preferred.

[0033] Examples of molybdenum complexes having a PNP-type pincer ligand include the molybdenum complex represented by the following chemical formulas (4) or (5). Examples of molybdenum complexes having a PCP-type pincer ligand and a halide ion include the molybdenum complex represented by the following chemical formulas (1) or (2). Other examples of molybdenum complexes include the molybdenum complex represented by the following chemical formula (3).

[0034] [ka]

[0035] In the above chemical formula (1), R 1 ~R 4 Each independently represents hydrogen or a chain, cyclic, or branched hydrocarbon group having 1 to 14 carbon atoms, and R 5is a group that substitutes hydrogen or a hydrogen atom in a ring, and represents a chain, cyclic, or branched hydrocarbon group having 1 to 14 carbon atoms, and X independently represents a halide ion selected from the group consisting of fluorine, chlorine, bromine, and iodine. Here, R 1 and R 2 , and / or R 3 and R 4 These may be bonded to each other to form a ring, PR 1 R 2 PR 3 R 4 It may be the same as or different from R 1 ~R 4 They may all be the same, or at least some of them may be different. R 1 ~R 5 The "chain, cyclic, or branched hydrocarbon group having 1 to 14 carbon atoms" in this context can be selected from the group consisting of, for example, alkyl groups having 1 to 6 carbon atoms, alkenyl groups having 2 to 6 carbon atoms, alkynyl groups having 2 to 6 carbon atoms, cycloalkyl groups having 3 to 6 carbon atoms, cycloalkenyl groups having 3 to 6 carbon atoms, cycloalkynyl groups having 3 to 6 carbon atoms, and aryl groups having 6 to 14 carbon atoms. Among these, R 1 ~R 4 As such, alkyl groups having 1 to 6 carbon atoms are preferred, and alkyl groups having 1 to 4 carbon atoms are more preferred. Also, R 1 ~R 4 A butyl group is preferred, and a tert-butyl group is more preferred. Also, R 5 If there are two or three of these R 5 They may be bonded to each other to form a ring. Also, R 5 If there are two or three of them, they may all be the same, or at least some of them may be different. X is preferably bromine, chlorine, or iodine, and more preferably chlorine or iodine. Here, X3 in the formula means that three X's are attached to Mo. The trihalogenated molybdenum moX3 may be replaced with monohalogenated nitride molybdenum MoXN, as shown below (the other ligand structures remain the same).

[0036] [ka]

[0037] [ka]

[0038] In the above chemical formula (2), R 1 ~R 5 And X is the same as in chemical formula (1) above. The trihalogenated molybdenum moX3 may be replaced with monohalogenated nitride molybdenum MoXN, as shown below (the other ligand structures remain the same).

[0039] [ka]

[0040] [ka]

[0041] In the above chemical formula (3), R 1 ~R 3 This is the same as chemical formula (1) above. Note that MoN2 may be replaced with MoN (the rest of the ligand structure remains the same).

[0042] [ka]

[0043] [ka]

[0044] In the above chemical formula (4), R 1 ~R 5 And X is the same as in chemical formula (1) above. The trihalogenated molybdenum moX3 may be replaced with monohalogenated nitride molybdenum MoXN, as shown below (the other ligand structures remain the same).

[0045] [ka]

[0046] [ka]

[0047] In the above chemical formula (5), R 1 ~R 5 And X is the same as in chemical formula (1) above. The trihalogenated molybdenum moX3 may be replaced with monohalogenated nitride molybdenum MoXN, as shown below (the other ligand structures remain the same).

[0048] [ka]

[0049] The concentration of the nitrogen-activated catalyst in the second electrolyte 41 is not particularly limited, but from the viewpoint of promoting the synthesis reaction of nitrogen-containing compounds, it is preferably, for example, 0.1 mmol / L or more and 1 mol / L or less.

[0050] In the second electrolyte 41, nitrogen (N2) fixed to the nitrogen-activated catalyst is reduced to produce ammonia, as shown in the following reaction equation.

[0051]

number

[0052] Although the detailed reaction pathway in the second electrolyte 41 is not yet clear, we believe that ammonia is produced from nitrogen through a catalytic cycle as shown in Figure 2.

[0053] In the catalytic cycle, one nitrogen atom of a nitrogen molecule (N2) coordinates to the molybdenum catalyst, forming complex (a) in which the nitrogen molecule is fixed to the molybdenum catalyst. Furthermore, the other nitrogen atom of the nitrogen molecule (N2) coordinates to another molybdenum catalyst, forming complex (b) which has a nitrogen-nitrogen triple bond and a bridging dinitrogen ligand structure. Subsequently, the nitrogen-nitrogen triple bond of complex (b) is cleaved, forming nitrogen-containing complex (c). In nitrogen-containing complex (c), the molybdenum atom and the nitrogen atom are bonded by a triple bond.

[0054] Protons and electrons are transferred to nitrogen-containing complex (c) to reduce the nitrogen atoms fixed in nitrogen-containing complex (c). As a result, complex (d) can be obtained. Finally, ammonia, the target product, is produced by exchanging the ammonia coordinated to the molybdenum complex for nitrogen.

[0055] In the second electrolyte 41, protons are reduced at the second electrode as shown in the following reaction equation, and hydrogen (H2) is produced as a by-product.

[0056]

number

[0057] In the second electrolytic cell 30, protons that react with nitrogen, electrons, and the nitrogen-activating catalyst are supplied as follows: They are supplied from the proton source of the first electrolytic cell 10 through the separator 60, via the proton mediator contained in the second electrolytic cell 30, or via the reducing agent contained in the second electrolytic cell 30, or from at least one of these sources. The supplied protons may be a combination of two or three. The ammonia production equipment can be appropriately selected based on its shape and size, or from the standpoint of efficiency and lifespan.

[0058] In the second electrolytic cell 30, electrons that react with nitrogen, protons, and the nitrogen-activating catalyst are supplied as follows: at least one of the following: electrons supplied from the second electrode 32, electrons supplied via an electron mediator contained in the second electrolytic cell 30, or electrons supplied via a reducing agent contained in the second electrolytic cell 30. Two or three electrons may be supplied in combination. The ammonia production equipment can be appropriately selected based on its shape and size, or from the standpoint of efficiency and lifespan.

[0059] Specific examples of reducing agents include compounds containing lanthanide metals. Preferably, the lanthanide metal is samarium, and more preferably, a compound containing a structure represented by the following formula, where M is samarium, X represents a single bond or a -SO2- group, R represents an alkyl group having 1 to 20 carbon atoms, a perfluoroalkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a perfluorocycloalkyl group having 3 to 20 carbon atoms, or an aromatic group which may have a substituent, and n represents an integer from 2 to 6.

[0060] [ka]

[0061] A proton mediator is a molecule that contains an atom with a non-bonding pair that is capable of accepting protons. Examples of proton mediators include 2,4,6-trimethylpyridinium trifluoromethanesulfonate ([ColH]OTf), represented by the following formula, as well as 2,4,6-trimethylpyridine (Col), 2,6-dimethylpyridinium trifluoromethanesulfonate ([LutH]OTf), and 2,6-dimethylpyridine (Lut).

[0062] [ka]

[0063] When the second electrolyte 41 contains a proton mediator, the proton mediator content is preferably 0.1 mmol / L or more and 2 mol / L or less, and more preferably 5 mmol / L or more and 1 mol / L or less.

[0064] An electron mediator is a compound that can receive electrons from the second electrode 32 and then transfer those electrons to the nitrogen-activated catalyst. Examples include cobaltocene, decamethylcobaltocene, and decamethylchromosene.

[0065] The ammonia production apparatus 1 includes a first separation unit 90 for separating ammonia from the second electrolytic medium 40. In embodiments where the second electrolytic medium 40 does not use an electrolyte, unreacted nitrogen and by-product hydrogen can be easily separated due to differences in boiling points. In embodiments where an electrolyte is used, the first separation unit 90 for separating ammonia from the second electrolyte 41 preferably comprises a 1-1 separation unit and a 1-2 separation unit, as described below. In the 1-1 separation section, the mixed gas A containing ammonia, by-product hydrogen, and unreacted nitrogen is separated by gas-liquid separation of the second electrolyte 41. Gas-liquid separation is performed in the second electrolytic cell 30, or in an optional second tank 34 (see Figure 4), etc. By bubbling nitrogen or the like into the second electrolyte 41, the gas dissolved in the second electrolyte 41 is expelled from the second electrolyte 41, and the mixed gas A containing ammonia, the by-product hydrogen, and unreacted nitrogen can be efficiently separated. Gas mixture A may contain gases other than ammonia, hydrogen, and nitrogen.

[0066] Examples of the first and second separation units include, for example, a cryogenic separation device that separates substances by utilizing the difference in boiling points, a membrane separation device that separates substances by utilizing the fact that the permeation rate of the membrane differs depending on the gas molecule, a pressure swing adsorption (PSA) device that separates substances by utilizing the difference in molecular size, or an adsorption separation device that separates substances by utilizing the difference in the adsorption characteristics of zeolite-based adsorbents for gas molecules.

[0067] The ammonia production apparatus 1 is configured to supply a mixed gas B containing hydrogen and unreacted nitrogen, which are by-products separated in the first separation unit 90, to the first electrolytic medium 20. The mixed gas B containing hydrogen and unreacted nitrogen, which are by-products separated in the first separation unit 90, is supplied to the first electrolytic medium 20, for example, through piping. With this configuration, the hydrogen produced as a byproduct can be used as a proton source.

[0068] The ammonia production apparatus 1 is preferably configured to include a second separation unit 100 for separating nitrogen from the first electrolytic medium 20, as shown in Figure 3, and to supply the nitrogen discharged from the second separation unit 100 to the second electrolytic medium 40. The description will be based on an embodiment in which the first electrolytic medium 20 uses an electrolyte. In the second separation unit 100, the nitrogen-containing gas mixture C is separated by gas-liquid separation of the first electrolyte 21. Gas-liquid separation is performed in the first electrolytic cell 10, or in a first tank 14 (see Figure 4), which can be optionally provided downstream of the first electrolytic cell 10. The gas mixture C may contain gases other than nitrogen. The mixed gas C is supplied to the second electrolytic medium 40, for example, through piping. With this configuration, unreacted nitrogen can be used as a raw material for ammonia. An example of this configuration is schematically shown in Figure 3.

[0069] Preferably, the ammonia production apparatus 1 further includes a nitrogen supply unit that supplies nitrogen to the second electrolytic medium 40. As ammonia production continues, the amount of nitrogen contained in the second electrolytic medium 40 decreases. Therefore, by providing a nitrogen supply unit that supplies nitrogen to the second electrolytic medium 40, the nitrogen contained in the second electrolytic medium 40 can be replenished, making it possible to continuously produce ammonia for a long period of time.

[0070] The nitrogen supply unit that supplies nitrogen to the second electrolytic medium 40 can be composed of, for example, a nitrogen supply device 82 that supplies nitrogen. The nitrogen supply device 82 may include, for example, a third separation unit that separates oxygen from the gas mixture to extract nitrogen. Methods for extracting nitrogen in the third separation unit include cryogenic separation, which utilizes the difference in boiling points to separate nitrogen, and membrane separation, which utilizes the fact that the permeation rate of the membrane differs depending on the gas molecule. The gas mixture supplied to the nitrogen supply device 82 may be air, a gas mixture C containing nitrogen supplied from the first electrolyte 21 described later, or nitrogen and oxygen supplied from the first electrolyte 21 described later.

[0071] When the proton source is water (H2O), oxygen is produced as a byproduct of the reaction that generates protons.

[0072] In a preferred embodiment of the present invention, the ammonia production apparatus 1 further comprises a first tank 14. The first electrolytic cell 10 and the first tank 14 are connected so that the first electrolyte 21 can flow through them. Specifically, the ammonia production apparatus 1 comprises a first circulation path 16 for circulating the first electrolyte 21 between the first electrolytic cell 10 and the first tank 14.

[0073] The first circulation path 16 includes a path 16a that sends the first electrolyte 21 from the first tank 14 to the first electrolytic cell 10, and a path 16b that sends the first electrolyte 21 from the first electrolytic cell 10 to the first tank 14. That is, the first electrolyte 21 circulates between the first electrolytic cell 10 and the first tank 14 through the first circulation path 16 (16a, 16b) in the direction of arrow 17. The first circulation path 16 is provided with a first pump (not shown) and is configured to enable the circulation of the first electrolyte 21 between the first tank 14 and the first electrolytic cell 10.

[0074] In the above description, the first electrolyte 21 was taken from the bottom of the first tank 14 and sent to the bottom of the first electrolytic cell 10 via the first circulation path 16a, and the first electrolyte 21 was taken from the top of the first electrolytic cell 10 and sent to the top of the first tank 14 via the first circulation path 16b as an example. However, the form in which the first electrolyte 21 is circulated is not limited to the above form. The first electrolyte 21 taken from the bottom of the first electrolytic cell 10 may be sent to the bottom of the first tank 14, and the first electrolyte 21 taken from the top of the first tank 14 may be sent to the top of the first electrolytic cell 10. Furthermore, the position from which the first electrolyte 21 is taken or sent in the first electrolytic cell 10 and the first tank 14 is not limited to the top or bottom of the first electrolytic cell 10 and the first tank 14, but may be any position.

[0075] As ammonia production continues, the amount of proton source contained in the first electrolyte 21 in the first electrolytic cell 10 decreases. By connecting the first tank 14 and the first electrolytic cell 10 in a way that allows the first electrolyte 21 to flow through, it becomes possible to supply a proton source from the first tank 14 to the first electrolytic cell 10.

[0076] Furthermore, a pipe for supplying a proton source may be provided in a part of the first circulation path 16, including the first tank 14. Alternatively, a pipe for supplying a new first electrolyte 21 may be provided in a part of the first circulation path 16, including the first tank 14. This has the advantage of enabling the continuous production of ammonia over a long period of time.

[0077] In a preferred embodiment of the present invention, the ammonia production apparatus 1 further comprises a second tank 34. The second electrolytic cell 30 and the second tank 34 are connected so that the second electrolyte 41 can flow through them. Specifically, the ammonia production apparatus 1 comprises a second circulation path 36 for circulating the second electrolyte 41 between the second electrolytic cell 30 and the second tank 34.

[0078] The second circulation path 36 includes a path 36a that sends the second electrolyte 41 from the second tank 34 to the second electrolytic cell 30, and a path 36b that sends the second electrolyte 41 from the second electrolytic cell 30 to the second tank 34. That is, the second electrolyte 41 circulates between the second electrolytic cell 30 and the second tank 34 through the second circulation path 36 (36a, 36b) in the direction of arrow 37. The second circulation path 36 is provided with a second pump (not shown) and is configured to enable the circulation of the second electrolyte 41 between the second tank 34 and the second electrolytic cell 30.

[0079] In the above description, the second electrolyte 41 was taken from the bottom of the second tank 34 and sent to the bottom of the second electrolytic cell 30 via the second circulation path 36a, and the second electrolyte 41 was taken from the top of the second electrolytic cell 30 and sent to the top of the second tank 34 via the second circulation path 36b as an example. However, the form of circulating the second electrolyte 41 is not limited to the above form. The second electrolyte 41 taken from the bottom of the second electrolytic cell 30 may be sent to the bottom of the second tank 34, and the second electrolyte 41 taken from the top of the second tank 34 may be sent to the top of the second electrolytic cell 30. Furthermore, the position from which the second electrolyte 41 is taken or sent in the second electrolytic cell 30 and the second tank 34 is not limited to the top or bottom of the second electrolytic cell 30 and the second tank 34, but may be any position.

[0080] As ammonia production continues, the amount of nitrogen in the second electrolyte 41 in the second electrolytic cell 30 decreases. By connecting the second tank 34 and the second electrolytic cell 30 in a way that allows the second electrolyte 41 to flow through, it becomes possible to supply nitrogen from the second tank 34 to the second electrolytic cell 30. [Explanation of Symbols]

[0081] 1. Ammonia production equipment 10 1st electrolytic cell 12 1st electrode 20 First electrolytic medium 30 Second electrolytic cell 32 2nd electrode 40 Second electrolytic medium 60 Separators 90 First Separation Section 100 Second Separation Section

Claims

1. A first electrolytic cell containing at least a portion of the first electrolytic medium, The first electrode is placed in the first electrolytic cell, A second electrolytic cell containing at least a portion of the second electrolytic medium, The second electrode is located in the second electrolytic cell, A separator is provided between the first electrolytic cell and the second electrolytic cell, A first separation unit for separating ammonia from the second electrolytic medium, An ammonia production apparatus comprising a second separation unit for separating nitrogen from the first electrolytic medium, In the first electrolytic cell, a proton source contained in the first electrolytic medium is oxidized at the first electrode, generating protons. The second electrolytic medium is configured to produce ammonia and hydrogen from nitrogen, protons, and electrons in the presence of a nitrogen-activated catalyst. The first separation unit is configured to supply nitrogen and hydrogen, which remain after ammonia separation, to the first electrolytic medium. An ammonia production apparatus configured such that the second separation unit supplies the separated nitrogen to the second electrolytic medium.

2. In the second electrolytic cell, nitrogen, electrons, and protons react in the presence of the nitrogen-activating catalyst, (i-1) Protons supplied from the proton source of the first electrolytic cell through the separator, (i-2) Protons supplied via the proton mediator contained in the second electrolytic cell, and (i-3) Proton supplied via the reducing agent contained in the second electrolytic cell The ammonia production apparatus according to claim 1, wherein at least one of the following:

3. In the second electrolytic cell, electrons react with nitrogen, protons, and the nitrogen-activating catalyst, (ii-1) Electrons supplied from the second electrode, (ii-2) Electrons supplied via the electron mediator contained in the second electrolytic cell, and (ii-3) Electrons supplied via the reducing agent contained in the second electrolytic cell The ammonia production apparatus according to claim 1, wherein at least one of the following:

4. The ammonia production apparatus according to claim 1, wherein the proton source is water.

5. The system further comprises a nitrogen supply device for supplying nitrogen to the second electrolytic medium, The ammonia production apparatus according to claim 4, wherein the nitrogen supply device comprises a third separation unit that supplies air to separate nitrogen and oxygen, and is configured to supply oxygen and nitrogen discharged from the first electrolytic cell to the nitrogen supply device.

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