JP2012221720A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell power generation system having excellent power generation efficiency and durability obtained by suppressing voltage reduction and deterioration such as an electrolyte by efficiently removing ammonia contained in fuel gas.SOLUTION: A fuel cell 101 includes an electrolyte layer for fuel cell, and a pair of catalyst layers for fuel cell formed so as to sandwich the electrolyte layer for fuel cell. An ammonia remover 104 includes an electrolyte layer for ammonia remover, and a catalyst layer for ammonia remover formed on at least one of surfaces of the electrolyte layer for ammonia remover. The ammonia remover 104 removes ammonia by using fuel gas and oxidant gas.

Description

  The present invention relates to a fuel cell system that generates power using a fuel gas containing hydrogen generated by steam reforming a raw material gas, and more particularly, a fuel gas containing hydrogen generated by steam reforming a raw material gas containing nitrogen. The present invention relates to a fuel cell system that generates electricity using the same.

  A fuel cell system is a system that generates electricity and heat by reacting a fuel gas containing at least hydrogen and an oxidant gas containing at least oxygen in a fuel cell, and directly or indirectly generates chemical energy of the fuel. Since it is converted into energy, high power generation efficiency can be obtained.

  The fuel gas is generally a hydrocarbon gas such as city gas mainly composed of methane, natural gas, LPG, naphtha, kerosene, light oil, methanol, ethanol, and dimethyl ether, and the raw material gas is a reforming catalyst. Produced by steam reforming, the main product is hydrogen.

  However, when nitrogen is contained in the raw material gas, hydrogen and nitrogen may react on the reforming catalyst to generate ammonia as a by-product.

  When fuel gas containing ammonia is supplied to the fuel cell, protons in the electrolyte layer constituting the fuel cell and ammonia may be combined to inhibit proton conduction and lower the voltage of the fuel cell.

  In some cases, ammonia poisons the catalyst constituting the anode or cathode of the fuel cell, thereby reducing the catalytic activity and lowering the voltage of the fuel cell.

  Furthermore, ammonia poisons the anode catalyst, thereby inhibiting the power generation reaction, and increasing the concentration of hydrogen peroxide and radicals may degrade the electrolyte and the like, thereby reducing the durability of the fuel cell.

  Therefore, conventionally, in order not to supply ammonia, which is an impurity contained in the fuel gas generated by reforming, to the fuel cell, the fuel gas path is provided with an adsorbent for adsorbing and removing ammonia, and the fuel from which ammonia has been removed A method for supplying gas to a fuel cell is disclosed. (For example, refer to Patent Document 1).

JP 2008-293964 A

  However, in the method of adsorbing and removing ammonia by the conventional adsorbent, it is not only necessary to periodically exchange the adsorbent from which ammonia has been collected, but also the problem that the ability to adsorb and remove ammonia decreases with the exposure time of ammonia. was there.

The present invention solves the above-described conventional problems, and efficiently removes ammonia contained in the fuel gas without using an ammonia absorbent, thereby suppressing voltage drop and electrolyte degradation. It aims to provide a fuel cell system with excellent durability.

  In order to solve the above-described conventional problems, the fuel cell system of the present invention includes an ammonia remover composed of an electrolyte layer and a catalyst layer, and removes ammonia using a fuel gas and an oxidant gas. .

  Thereby, by removing ammonia contained in the fuel gas, it is possible to suppress a voltage drop due to ammonia and deterioration of the electrolyte.

  According to the fuel cell system of the present invention, since the voltage drop due to ammonia and the deterioration of the electrolyte and the like are suppressed, the power generation efficiency and durability of the fuel cell system can be improved.

1 is a schematic diagram showing a schematic configuration of a fuel cell system according to Embodiment 1 of the present invention. 1 is a schematic diagram showing a schematic configuration of a fuel cell of the fuel cell system shown in FIG. Sectional drawing which shows the schematic structure of the cell in a fuel cell typically Schematic diagram showing a schematic configuration of a fuel cell according to Embodiment 2 of the present invention.

The first invention is
A fuel gas supply device for reforming the raw material gas to produce and supply a fuel gas containing hydrogen;
An oxidant gas supply device for supplying an oxidant gas containing oxygen;
A fuel cell that generates electricity by reacting the fuel gas supplied from the fuel gas supply device with the oxidant gas supplied from the oxidant gas supply device; and
An ammonia remover for removing ammonia in the fuel gas supplied from the fuel gas supplier;
A fuel cell system comprising:
The fuel cell has a fuel cell electrolyte layer and a pair of fuel cell catalyst layers formed so as to sandwich the fuel cell electrolyte layer,
The ammonia remover has an ammonia remover electrolyte layer and an ammonia remover catalyst layer formed on at least one surface of the ammonia remover electrolyte layer surface,
The ammonia remover removes ammonia using the fuel gas and the oxidant gas.

  With this configuration, unlike ammonia removal by adsorption or the like, it is possible to maintain the ammonia removal performance without replacing the ammonia remover, remove ammonia contained in the fuel gas, and remove the ammonia contained in the fuel cell. The voltage drop and the deterioration of the electrolyte layer in the fuel cell can be suppressed, and the power generation efficiency and durability of the fuel cell system can be improved.

According to a second invention, in the first invention,
The ammonia removing device catalyst layer is formed only on a side to which the oxidizing gas is supplied.

With this configuration, it is possible to remove ammonia even in a state where the catalyst layer for the ammonia remover is not formed on the side where the fuel gas is supplied to the ammonia remover, and the voltage drop of the fuel cell due to ammonia, Deterioration of the electrolyte layer and the like in the fuel cell can be suppressed, and both improvement in power generation efficiency and durability of the fuel cell system and reduction in the ammonia remover cost can be achieved.

A third invention is the invention according to any one of the first to second inventions,
The catalyst amount per unit area contained in the ammonia remover catalyst layer of the ammonia remover is smaller than the catalyst amount per unit area contained in the fuel cell catalyst layer of the fuel cell.

  With this configuration, the ammonia remover is more likely to generate radicals due to a small amount of platinum catalyst that suppresses radicals generated in the ammonia remover. And the radical generated in the ammonia remover decomposes the ammonia contained in the fuel gas, so that the voltage drop of the fuel cell due to ammonia and the deterioration of the electrolyte layer in the fuel cell can be suppressed, The power generation efficiency and durability of the fuel cell system can be improved.

According to a fourth invention, in any one of the first to third inventions,
The particle size of the catalyst contained in the ammonia remover catalyst layer of the ammonia remover is larger than the particle size of the catalyst contained in the fuel cell catalyst layer.

  With this configuration, the catalyst of the catalyst layer for the ammonia remover has a smaller surface area of the catalyst than the catalyst used for the catalyst layer for the fuel cell, and the platinum catalyst that effectively contributes to the reaction. Since the effect of suppressing radicals generated in the ammonia remover is reduced, radicals are more easily generated. And the radical generated in the ammonia remover decomposes the ammonia contained in the fuel gas, so that the voltage drop of the fuel cell due to ammonia and the deterioration of the electrolyte layer in the fuel cell can be suppressed, The power generation efficiency and durability of the fuel cell system can be improved.

According to a fifth invention, in any one of the first to fourth inventions,
The ratio of the electrolytic mass with respect to the catalyst amount contained in the catalyst layer for the ammonia remover of the ammonia remover is larger than the ratio of the electrolytic mass with respect to the catalyst amount contained in the catalyst layer for the fuel cell.

  With this configuration, the catalyst layer for the ammonia remover has a higher ratio of being covered with the electrolyte than the catalyst layer for the fuel cell, and the platinum catalyst that effectively contributes to the reaction is reduced. Therefore, the ammonia remover Since the effect of suppressing the radicals generated inside becomes small, radicals are more easily generated. And the radical generated in the ammonia remover decomposes the ammonia contained in the fuel gas, so that the voltage drop of the fuel cell due to ammonia and the deterioration of the electrolyte layer in the fuel cell can be suppressed, The power generation efficiency and durability of the fuel cell system can be improved.

A sixth invention is any one of the first to fifth inventions,
The ammonia remover electrolyte layer of the ammonia remover is thinner than the fuel cell electrolyte layer.

  With this configuration, the amount of fuel gas that permeates from the cathode side to the anode side of the ammonia remover is greater than the amount of fuel gas that permeates from the cathode side to the anode side of the fuel cell, so that radicals are more easily generated. . And the radical generated in the ammonia remover decomposes the ammonia contained in the fuel gas, so that the voltage drop of the fuel cell due to ammonia and the deterioration of the electrolyte layer in the fuel cell can be suppressed, The power generation efficiency and durability of the fuel cell system can be improved.

A seventh invention is any one of the first to sixth inventions,
The radical generated in the ammonia remover is a hydroxy radical.

  With this configuration, highly reactive hydroxy radicals can decompose ammonia contained in the fuel gas and suppress the voltage drop of the fuel cell due to ammonia and the deterioration of the electrolyte layer in the fuel cell. The power generation efficiency and durability of the system can be improved.

According to an eighth invention, in any one of the first to seventh inventions,
The fuel gas is supplied from the fuel gas supply device to the fuel cell via the ammonia remover, and the oxidant gas is supplied from the oxidant gas supply device to the fuel cell via the ammonia removal device. It is comprised so that it may be comprised.

  With this configuration, the fuel gas passes through the ammonia remover and then is supplied to the fuel cell. The ammonia remover removes the ammonia contained in the fuel gas, and the fuel cell is made of ammonia. The voltage drop and the deterioration of the electrolyte layer in the fuel cell can be suppressed, and the power generation efficiency and durability of the fuel cell system can be improved.

According to a ninth invention, in any one of the first to eighth inventions,
The fuel cell and the ammonia remover are integrally configured.

  With this configuration, the volume including the fuel cell, the ammonia remover, and the piping connecting them can be reduced, and the radical generated in the ammonia remover is contained in the fuel gas in a more compact system. Ammonia can be decomposed to suppress the voltage drop of the fuel cell due to ammonia and the deterioration of the electrolyte layer in the fuel cell, and the power generation efficiency and durability of the fuel cell system can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the same components as those of the above-described embodiments will be denoted by the same reference numerals, and detailed description thereof will be omitted. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
The fuel cell system according to Embodiment 1 of the present invention exemplifies a mode in which the ammonia remover decomposes ammonia contained in the fuel gas.

[Configuration of fuel cell system]
FIG. 1 is a schematic diagram showing a schematic configuration of a fuel cell system according to Embodiment 1 of the present invention.

  As shown in FIG. 1, a fuel cell system 100 according to Embodiment 1 of the present invention includes a fuel cell 101 having an anode 4A, a cathode 4B, a fuel gas path 101A, and an oxidant gas path 101B. An ammonia remover 104, an output controller 105, a water supplier 106, and a source gas supplier 107 having a gas supplier 102, an oxidant gas supplier 103, a fuel gas path 104A, and an oxidant gas path 104B. I have. The ammonia remover 104 is configured between the fuel cell 101, the fuel gas supply device 102, and the oxidant gas supply device 103. The fuel gas and the oxidant gas containing ammonia pass through the ammonia remover 104, It is configured to be supplied to the fuel cell 101. The ammonia remover 104 is configured without being electrically connected to the output controller 105 connected to the fuel cell 101.

  Here, the fuel gas containing ammonia refers to a mixed gas containing hydrogen gas as a main component and containing at least ammonia.

  The oxidant gas supply unit 103 may have any form as long as the oxidant gas supply unit 103 is configured to supply the oxidant gas path 101B of the fuel cell 101 and the oxidant gas path 104B of the ammonia remover 104 to each other. For example, fans such as a blower and a sirocco fan can be used.

[Configuration of fuel cell]
Next, the configuration of the fuel cell 101 of the fuel cell system 100 according to Embodiment 1 will be described with reference to FIG.

  FIG. 2 is a schematic diagram showing a schematic configuration of the fuel cell 101 of the fuel cell system 100 shown in FIG.

  As shown in FIG. 2, the fuel cell 101 includes a cell stack 80 in which a plurality of cells 21 are stacked in the thickness direction, end plates 81 and 82 disposed at both ends of the cell stack 80, and a cell stack. And a fastener (not shown) that fastens the body 80 and the end plates 81 and 82 in the stacking direction of the cells 21. Further, an insulating plate and a current collector plate (both not shown) are arranged between the end plate 81 and the cell laminate 80, and an insulating plate is provided between the end plate 82 and the cell laminate 80. And a current collector plate (both not shown) are arranged.

  The cell stack 80 is provided with a fuel gas supply manifold 31, an oxidant gas supply manifold 33, a fuel gas discharge manifold 32, and an oxidant gas discharge manifold 34 so as to extend in the stacking direction of the cells 21. A fuel gas supply path 41 is connected to the fuel gas supply manifold 31, and a fuel gas discharge path 42 is connected to the fuel gas discharge manifold 32 (see FIG. 1). Further, an oxidant gas supply path 51 is connected to the oxidant gas supply manifold 33, and an oxidant gas discharge path 52 is connected to the oxidant gas discharge manifold 34 (see FIG. 1).

[Cell structure]
Next, the cell 21 of the fuel cell 101 in the fuel cell system 100 according to Embodiment 1 will be described with reference to FIG.

  FIG. 3 is a cross-sectional view schematically showing a schematic configuration of the cell 21 in the fuel cell 101 shown in FIG. In FIG. 3, a part is omitted.

  As shown in FIG. 3, the cell 21 includes an MEA (Membrane-Electrode-Assembly: membrane-electrode assembly 5), a gasket 7, an anode separator 6A, and a cathode separator 6B.

  The MEA 5 includes an electrolyte layer (polymer electrolyte membrane) 1 that selectively transports hydrogen ions, an anode 4A, and a cathode 4B. The electrolyte layer 1 has a substantially quadrangular (here, rectangular) shape, and an anode 4A and a cathode 4B are provided on both surfaces of the electrolyte layer 1 so as to be located inward from the peripheral edge thereof. ing. In the peripheral portion of the electrolyte layer 1, manifold holes such as fuel gas supply manifold holes (not shown) are provided so as to penetrate in the thickness direction.

The anode 4A is provided on one main surface of the electrolyte layer 1, and is a platinum-based metal catalyst (electrode catalyst).
An anode catalyst layer 2A including a catalyst-supported carbon made of carbon powder (conductive carbon particles) supporting the catalyst, a polymer electrolyte attached to the catalyst-supported carbon, an anode gas diffusion layer 3A having both gas permeability and conductivity, have. The anode catalyst layer 2A is arranged such that one main surface is in contact with the electrolyte layer 1, and the anode gas diffusion layer 3A is arranged on the other main surface of the anode catalyst layer 2A. Similarly, the cathode 4B is provided on the other main surface of the electrolyte layer 1, and is attached to the catalyst-supporting carbon and the catalyst-supporting carbon made of carbon powder (conductive carbon particles) supporting a platinum-based metal catalyst (electrode catalyst). A cathode catalyst layer 2B containing the polymer electrolyte, and a cathode gas diffusion layer 3B provided on the cathode catalyst layer 2B and having both gas permeability and conductivity. The cathode catalyst layer 2B is disposed such that one main surface is in contact with the electrolyte layer 1, and the cathode gas diffusion layer 3B is disposed on the other main surface of the cathode catalyst layer 2B.

  A pair of fluorine rubber doughnut-shaped gaskets 7 are disposed around the anode 4A and the cathode 4B of the MEA 5 with the electrolyte layer 1 interposed therebetween. This prevents fuel gas and oxidant gas from leaking out of the battery, and prevents these gases from being mixed with each other in the cell 21. Note that manifold holes such as a fuel gas supply manifold hole (not shown) including through holes in the thickness direction are provided at the peripheral edge of the gasket 7.

  In addition, a conductive anode separator 6A and a cathode separator 6B are disposed so as to sandwich the MEA 5 and the gasket 7. Thereby, MEA 5 is mechanically fixed, and when a plurality of cells 21 are stacked in the thickness direction, MEA 5 is electrically connected. The anode separator 6A and the cathode separator 6B can be made of a metal having excellent thermal conductivity and conductivity, graphite, or a mixture of graphite and resin. For example, carbon powder and binder (solvent ) And a mixture obtained by injection molding, or a surface of a titanium or stainless steel plate plated with gold can be used.

  A groove-like fuel gas flow path 8 through which fuel gas flows is provided on one main surface (hereinafter referred to as an inner surface) of the anode separator 6A that contacts the anode 4A. Similarly, a groove-like oxidant gas flow path 9 through which an oxidant gas flows is provided on one main surface (hereinafter referred to as an inner surface) that contacts the cathode 4B of the cathode separator 6B. In addition, each manifold hole such as a fuel gas supply manifold hole (not shown) is provided in the peripheral edge of each of the anode separator 6A and the cathode separator 6B so as to penetrate in the thickness direction. The fuel gas flow path 8 and the oxidant gas flow path 9 may have any shape. For example, the fuel gas flow path 8 and the oxidant gas flow path 9 may be formed in a serpentine shape or a straight shape when viewed from the thickness direction of the cell 21. Good.

  Thereby, fuel gas and oxidant gas are supplied to the anode 4A and the cathode 4B, respectively, and these gases react to generate electricity and heat.

And the cell laminated body 80 is formed by laminating | stacking the cell 21 formed in this way in the thickness direction. At this time, each manifold hole such as a fuel gas supply manifold hole (not shown) provided in the polymer electrolyte membrane 1 or the like is connected to form each manifold such as the fuel gas supply manifold 31 (see FIG. 2). . The fuel gas supply manifold 31, the fuel gas passage 8, and the fuel gas discharge manifold 32 constitute a fuel gas path 101A. The inlet of the fuel gas supply manifold 31 constitutes the inlet of the fuel gas path 101A, and the outlet of the fuel gas discharge manifold 32 constitutes the outlet of the fuel gas path 101A. The oxidant gas supply manifold 33, the oxidant gas flow path 9, and the oxidant gas discharge manifold 34 constitute an oxidant gas path 101B. The inlet of the oxidant gas supply manifold 33 constitutes the inlet of the oxidant gas path 101B, and the outlet of the oxidant gas discharge manifold 34 constitutes the outlet of the oxidant gas path 101B.

[Configuration of fuel gas supply unit]
The fuel gas supply unit 102 includes an evaporator 102A and a reformer 102B.

  A water supply device 106 is connected to the evaporator 102 </ b> A via a water supply path 61. The water supply device 106 may be in any form as long as the water flow rate can be adjusted and supplied to the evaporator 102A. For example, the water supply device 106 may be a flow rate adjustment device that adjusts the flow rate of water. The flow rate regulator may be constituted by a single flow rate adjustment valve or a single pump, or may be constituted by a combination of a pump and a flow rate adjustment valve. The evaporator 102A is configured to vaporize the water supplied from the water supplier 106 and supply water vapor to the reformer 102B. In the first embodiment, of the water (steam) vaporized by the evaporator 102A from the water supplied from the water supplier 106, excess steam that has not been used for the reforming reaction humidifies the fuel gas. To do.

  In addition, a raw material gas supply unit 107 is connected to the evaporator 102 </ b> A via a raw material gas supply path 62. The source gas supply unit 107 may be in any form as long as the source gas flow rate can be supplied to the evaporator 102A by adjusting the flow rate of the source gas. For example, the source gas supply unit 107 may be constituted by a single flow rate adjustment valve or a single booster pump. Moreover, it may be configured by a combination of a booster pump and a flow rate adjusting valve. As a result, the source gas is supplied from the source gas supply unit 107 to the evaporator 102A via the source gas supply path 62, and is heated by the evaporator 102A.

  The reformer 102B has a reforming catalyst that generates a hydrogen-containing gas by reforming the raw material gas and water. In the reformer 102B, the raw material gas supplied from the evaporator 102A and the water vapor undergo a reforming reaction to generate a hydrogen-containing gas, and the generated hydrogen-containing gas is used as a fuel gas as a fuel gas supply path 41. To be supplied. In the reformer 102B, hydrogen produced by the reforming reaction reacts with nitrogen contained in the raw material gas to produce ammonia.

  In addition, as source gas, what contains the organic compound which uses carbon and hydrogen as a structural element at least, such as hydrocarbons, such as ethane and propane, can be used, for example. In the first embodiment, gas supplied from a gas infrastructure line such as city gas (natural gas) or LP gas is used. These source gases contain nitrogen derived from the source. In addition, the source gas supply unit 107 may be configured to include a deodorizer that removes odorous components (for example, mercaptans) contained in city gas (natural gas) mainly composed of methane. In this case, the deodorizer may have a configuration having activated carbon or a filter, a configuration using a zeolite-based adsorbent that removes odorous components by adsorption, or a configuration using a hydrodesulfurization catalyst.

  In the first embodiment, the source gas from the source gas supply unit 107 is supplied to the evaporator 102A and then supplied to the reformer 102B. However, the present invention is not limited to this, and the source gas is used. A mode in which the source gas is directly supplied from the supplier 107 to the reformer 102B via the source gas supply path 62 may be adopted. Further, in Embodiment 1, the form in which the evaporator 102A is provided is adopted, but the present invention is not limited to this, and a form in which the evaporator 102A is not provided may be adopted. In this case, water is vaporized into steam in the reformer 102B, and the reformer 102B also functions as the evaporator 102A.

Furthermore, in the first embodiment, the hydrogen-containing gas generated in the reformer 102B is sent to the fuel gas supply path 41. However, the present invention is not limited to this, and the hydrogen gas is generated in the fuel gas supply device 102. A shifter having a shift catalyst (for example, a copper-zinc based catalyst) for reducing carbon monoxide in the hydrogen-containing gas sent from the reformer 102B, an oxidation catalyst (for example, a ruthenium based catalyst), methane, The hydrogen-containing gas after passing through the carbon monoxide remover having the fluorination catalyst (for example, ruthenium-based catalyst) may be sent to the fuel gas supply path 41.

  Here, for example, a chemical reaction when methane is used as the source gas will be described. In the reformer 102B, the reactions shown in (Chemical Formula 1) and (Chemical Formula 2) occur with the water vapor from the evaporator 102A, and hydrogen is generated.

  In addition, the reaction shown in (Chemical Formula 3) is performed by summing up all reactions that occur in the reformer 102B.

  By the way, when nitrogen is contained in the raw material gas, hydrogen produced on the reforming catalyst of the reformer 102B may react with nitrogen to produce ammonia (Chemical Formula 4).

  Ammonia binds to protons to become cations, and the proton conductive electrolyte layer 1 becomes a substance that traps protons and lowers the proton conductivity in the electrolyte layer 1.

  In addition, when ammonia poisons the catalyst constituting the anode 4A and the cathode 4B of the fuel cell 101, the catalyst activity may be reduced and the battery voltage may be lowered.

  Further, when ammonia poisons the anode catalyst of the anode 4A, the power generation reaction is inhibited, the concentration of hydrogen peroxide and radicals increases, the electrolyte layer 1 and the like deteriorate, and the durability may be lowered.

[Configuration of ammonia remover]
Next, the configuration of the ammonia remover 104 of the fuel cell system 100 according to Embodiment 1 will be described.

  The ammonia remover 104 has the same configuration as the fuel cell 101. However, the ammonia remover 104 does not necessarily need to be connected to the output controller 105 (a device that boosts and converts direct current to alternating current and outputs it to an external load). It is not always necessary to arrange the current collector plate between the two.

  Further, the number of cells in the cell stack only needs to satisfy the number of cells necessary for removing ammonia, and does not necessarily have the same configuration as the fuel cell 101.

  Furthermore, regarding the MEA and separator constituting the cell, a sufficient amount of radicals may be generated to remove ammonia, and the configuration is not necessarily the same as that of the fuel cell 101.

  Here, the radical generation mechanism of the ammonia remover 104 will be described. Hydrogen supplied to the anode 4A generates protons by the reaction shown in (Chemical Formula 5) and causes the reaction shown in (Chemical Formula 6) with oxygen in the oxidant gas to generate hydrogen peroxide.

  This hydrogen peroxide causes the reaction shown in (Chemical Formula 7) with protons to generate hydroxy radicals.

  A hydroxy radical is a radical (.OH) corresponding to a hydroxyl group, has high reactivity, and can decompose ammonia (Chemical Formula 8).

  Accordingly, the hydroxy radical generated in the ammonia remover 104 can be decomposed and removed from the ammonia contained in the fuel gas, and the supply of ammonia to the fuel cell 101 can be suppressed. The power generation reaction due to poisoning can be inhibited and deterioration of the electrolyte layer 1 can be suppressed.

  The thickness of the electrolyte layer for the fuel cell of the fuel cell produced in Example 1 performed in Examples 1 to 6, the amount of catalyst per unit area contained in the catalyst layer for the fuel cell, the particle size of the catalyst, The electrolyte ratio is shown in Table 1.

Table 2 shows the thickness of the electrolyte layer for the ammonia remover of the ammonia remover, the amount of catalyst per unit area contained in the catalyst layer for the ammonia remover, the particle size of the catalyst, and the ratio of the electrolyte.

  The same fuel cell was used, only the ammonia remover was replaced, and the voltage was evaluated at a voltage of 24 h after power generation.

  Further, the ammonia concentration of the fuel gas measured at the inlet of the ammonia remover was 10 ppm.

Comparative example

  The thickness of the electrolyte layer for the ammonia remover of the ammonia remover produced in Embodiment 1 performed in Comparative Examples 1 and 2, the amount of catalyst per unit area contained in the catalyst layer for the ammonia remover, and the particle size of the catalyst The ratio of the electrolyte is shown in Table 3.

  The same fuel cell was used, only the ammonia remover was replaced, and the voltage was evaluated at a voltage of 24 h after power generation.

  Further, the ammonia concentration of the fuel gas measured at the inlet of the ammonia remover was 10 ppm.

  The results of evaluating the fuel cell stack voltage as described above are shown in Table 4.

  From Table 4, the ammonia remover of Example 1 suppresses the voltage drop due to ammonia because the voltage is increased compared to Comparative Example 1 in which the catalyst layer is not formed and the function of the ammonia remover is not provided. It is thought that there is an effect to do.

  This is presumably because the radical generated in the ammonia remover decomposes ammonia to suppress the supply of ammonia to the fuel cell.

  From Table 4, the ammonia remover of Example 2 has a higher voltage than Comparative Example 1 in which the catalyst layer is not formed and the ammonia remover has no function. It is thought that there is an effect to do.

  Furthermore, compared with Comparative Example 2 in which the catalyst layer is formed only on the anode, the voltage is increased only in Example 2, so that even when the catalyst layer is formed only on the cathode, the effect of suppressing the voltage drop due to ammonia is suppressed. It is believed that there is.

  Thus, it is considered that the formation of a cathode catalyst layer is indispensable for generating radicals with an ammonia remover.

  From Table 4, the ammonia remover of Example 3 suppresses the voltage drop due to ammonia because the voltage is increased compared to Comparative Example 1 in which the catalyst layer is not formed and the function of the ammonia remover is not provided. It is thought that there is an effect to do.

  Furthermore, compared with Example 1, since the voltage of Example 3 is further increased, it is considered that the smaller the amount of catalyst in the catalyst layer for the ammonia remover, the greater the effect of suppressing the voltage drop due to ammonia. .

  From Table 4, the ammonia remover of Example 4 has a higher voltage than that of Comparative Example 1 in which the catalyst layer is not formed and the ammonia remover has no function. It is thought that there is an effect to do.

  Furthermore, compared with Example 1, since the voltage of Example 4 has risen more, it is thought that the larger the catalyst particle size in the catalyst layer for ammonia remover, the greater the effect of suppressing the voltage drop due to ammonia. It is done.

  From Table 4, the ammonia remover of Example 5 is suppressed in voltage drop due to ammonia because the voltage is increased compared to Comparative Example 1 in which the catalyst layer is not formed and the function of the ammonia remover is not provided. It is thought that there is an effect to do.

  Furthermore, compared with Example 1, since the voltage of Example 5 is rising more, it is thought that the effect which suppresses the voltage drop by ammonia is large, so that the electrolyte ratio in the catalyst layer for ammonia removal devices is large. .

  From Table 4, the ammonia remover of Example 6 suppresses the voltage drop due to ammonia because the voltage is increased compared to Comparative Example 1 in which the catalyst layer is not formed and the function of the ammonia remover is not provided. It is thought that there is an effect to do.

  Furthermore, compared with Example 1, since the voltage of Example 6 is rising more, it is thought that the thinner one in the electrolyte layer for ammonia removers has a larger effect of suppressing the voltage drop due to ammonia. .

  In addition, this invention is applicable to the various form which embodiment described above can be changed easily from the meaning of this specification.

  Further, the present invention can be applied to various fuel cell systems including a fuel processor that reforms a hydrocarbon-based gas containing nitrogen and generates hydrogen.

(Embodiment 2)
The fuel cell system according to Embodiment 2 of the present invention exemplifies a form in which an ammonia remover and a fuel cell are integrally formed.

[Configuration of fuel cell]
The configuration of the ammonia remover-integrated fuel cell 202 according to the second embodiment will be described with reference to FIG.

  FIG. 4 is a schematic diagram showing a schematic configuration of an ammonia remover integrated fuel cell 202 in which the ammonia remover 104 and the fuel cell 101 are integrally formed in the fuel cell system 100 shown in FIG.

  As shown in FIG. 4, the ammonia remover integrated fuel cell 202 includes an end plate 83, an insulating plate 85, and a plurality of cells 21 in the thickness direction from the fuel gas supply path 41 and the oxidant gas supply path 51 side. The stacked cell stack 89, the insulating plate 86, the current collector 91, the cell stack 80 in which the plurality of cells 21 are stacked in the thickness direction, the current collector 92, the insulating plate 87, and the end plate 84 are arranged in this order. And a fastener (not shown) for fastening them in the stacking direction.

  In the ammonia remover integrated fuel cell 202, the fuel gas discharge path of the ammonia remover section is connected to the fuel gas supply path of the fuel cell section, and the oxidant gas discharge path of the ammonia remover section is the fuel cell. Connected to the oxidant gas supply path.

  The fuel cell system 100 according to the second embodiment configured as described above can be configured as a more compact system than the first embodiment.

  According to the fuel cell power generation system of the embodiment of the present invention, not only the ammonia contained in the fuel gas but also the ammonia contained in the oxidant gas can be decomposed. Even when ammonia is contained, ammonia can be decomposed, voltage drop due to ammonia can be suppressed, and power generation efficiency of the fuel cell power generation system can be improved.

  As described above, the fuel cell power generation system according to the present invention is effective for a fuel cell system that generates power by generating fuel gas using a raw material gas containing nitrogen, and is hardly affected by ammonia in the fuel gas. It can be applied to uses such as a fuel cell using a polymer type solid electrolyte, a fuel cell device, and a stationary fuel cell cogeneration system, where improvement in power generation efficiency is desired.

1 Polymer electrolyte membrane (electrolyte layer)
2A Anode catalyst layer 2B Cathode catalyst layer 3A Anode gas diffusion layer 3B Cathode gas diffusion layer 4A Anode 4B Cathode 5 MEA (Membrane-Electrode-Assembly: Membrane-electrode assembly)
6A Anode separator 6B Cathode separator 7 Gasket 8 Fuel gas flow path 9 Oxidant gas flow path 21 Cell 31 Fuel gas supply manifold 32 Fuel gas discharge manifold 33 Oxidant gas supply manifold 34 Oxidant gas discharge manifold 41 Fuel gas supply path 42 Fuel Gas discharge path 51 Oxidant gas supply path 52 Oxidant gas discharge path 61 Water supply path 62 Raw material gas supply path 80 Cell stack 81 End plate 82 End plate 83 End plate 84 End plate 85 Insulating plate 86 Insulating plate 87 Insulating plate 89 Cell stack 100 Fuel cell system 101 Fuel cell 101A Fuel gas path 101B Oxidant gas path 102 Fuel gas supply 102A Evaporator 102B Reformer 103 Oxidant gas supply 104 Ammonia remover 104A Fuel gas path 104B Acid Containing gas path 105 output controller 106 water supplying device 107 raw material gas supply unit

Claims (9)

A fuel gas supply device for reforming the raw material gas to produce and supply a fuel gas containing hydrogen;
An oxidant gas supply device for supplying an oxidant gas containing oxygen;
A fuel cell that generates electricity by reacting the fuel gas supplied from the fuel gas supply device with the oxidant gas supplied from the oxidant gas supply device; and
An ammonia remover for removing ammonia in the fuel gas supplied from the fuel gas supplier;
A fuel cell system comprising:
The fuel cell has a fuel cell electrolyte layer and a pair of fuel cell catalyst layers formed so as to sandwich the fuel cell electrolyte layer,
The ammonia remover has an ammonia remover electrolyte layer and an ammonia remover catalyst layer formed on at least one surface of the ammonia remover electrolyte layer surface,
The ammonia remover removes ammonia using the fuel gas and the oxidant gas;
Fuel cell system. The catalyst layer for the ammonia remover is formed only on the side to which the oxidant gas is supplied,
The fuel cell system according to claim 1. The catalyst amount per unit area contained in the ammonia remover catalyst layer of the ammonia remover is configured to be smaller than the catalyst amount per unit area contained in the fuel cell catalyst layer.
The fuel cell system according to claim 1 or 2. The particle size of the catalyst contained in the ammonia remover catalyst layer of the ammonia remover is configured to be larger than the particle size of the catalyst contained in the fuel cell catalyst layer.
The fuel cell system according to any one of claims 1 to 3. The ratio of the electrolysis mass with respect to the catalyst amount contained in the ammonia remover catalyst layer of the ammonia remover is configured to be larger than the ratio of the electrolysis mass with respect to the catalyst amount contained in the fuel cell catalyst layer.
The fuel cell system according to any one of claims 1 to 4. The ammonia remover electrolyte layer of the ammonia remover is configured to be thinner than the fuel cell electrolyte layer.
The fuel cell system according to any one of claims 1 to 5. The ammonia remover generates hydroxy radicals;
The fuel cell system according to any one of claims 1 to 6. The fuel gas is supplied from the fuel gas supply device to the fuel cell via the ammonia remover, and the oxidant gas is supplied from the oxidant gas supply device to the fuel cell via the ammonia removal device. It is configured so that,
The fuel cell system according to any one of claims 1 to 7. The fuel cell and the ammonia remover are configured integrally.
The fuel cell system according to any one of claims 1 to 8.