JP2008027752A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system which has the ammonia removal means and the capability to supply the stable power over a long period of time. <P>SOLUTION: The fuel cell system includes, at a minimum, a reformer 1 for generating the fuel gas from the supplied raw fuel through the steam reforming reaction, and a polymer electrolyte fuel cell 14 for generating the power from the supplied fuel gas through the electrochemical reaction, while ejecting the discharged fuel gas. Furthermore, the fuel cell system incorporates an ammonia pump 23 which extracts the ammonia from the fuel gas generated by the reformer, supplies the fuel gas with the ammonia extracted to the polymer electrolyte fuel cell, and mixes the extracted ammonia with the discharged fuel gas ejected from the polymer electrolyte fuel cell. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell system that generates power by supplying a fuel gas to a fuel cell, and more particularly, a polymer electrolyte fuel cell that generates power by supplying a fuel gas generated using city gas to a polymer electrolyte fuel cell. About the system.

  2. Description of the Related Art Conventionally, a fuel cell cogeneration system (hereinafter simply referred to as a “fuel cell system”) with high power generation efficiency and overall efficiency has attracted attention as a small-scale power generation apparatus that can effectively use energy.

  The fuel cell system includes a fuel cell as a main body of the power generation unit. As this fuel cell, for example, a polymer electrolyte fuel cell is preferably used. By the way, this polymer electrolyte fuel cell generates power using hydrogen and oxygen. However, the hydrogen supply means is not usually established as an infrastructure. Therefore, in order to obtain electric power from the polymer electrolyte fuel cell system, it is necessary to generate hydrogen at the place where the polymer electrolyte fuel cell system is installed. Therefore, in a conventional polymer electrolyte fuel cell system, a reformer is usually provided in addition to the polymer electrolyte fuel cell. In this reformer, hydrogen-containing fuel gas is obtained by using hydrocarbon-based raw fuel such as city gas, propane gas, naphtha, gasoline, kerosene, or alcohol-based raw fuel such as methanol and water. Is generated. Each of the fuel gas generated in the reformer and the oxidant gas such as oxygen-containing air is supplied to the polymer electrolyte fuel cell, and the polymer electrolyte fuel cell system outputs desired power. To do.

  Here, the configuration and operation of a conventional polymer electrolyte fuel cell system (hereinafter simply referred to as “fuel cell system”) will be outlined.

  FIG. 5 is a block diagram schematically showing a configuration of a conventional fuel cell system including a polymer electrolyte fuel cell and a reformer.

  As shown in FIG. 5, the conventional fuel cell system 300 includes a reformer 101, a condenser 102 and a condensed water tank 103, and a condenser 104 and a condensed water tank 105. The reformer 101 generates a fuel gas containing hydrogen by advancing a steam reforming reaction using city gas and water as raw fuel. The condensers 102 and 104 convert water vapor into water (condensed water) with a predetermined cooling configuration using secondary cooling water. The condensed water tanks 103 and 105 store water (condensed water).

  The conventional fuel cell system 300 includes an air supply device 106, a humidifier 107, a condenser 108, and a condensed water tank 109. The air supply device 106 introduces air as an oxidant gas into the fuel cell system 300 from the atmosphere. The humidifier 107 humidifies air as an oxidant gas with a predetermined humidification configuration using primary cooling water. The condenser 108 converts water vapor into water (condensed water) with a predetermined cooling configuration using secondary cooling water. The condensed water tank 109 stores water (condensed water).

  The conventional fuel cell system 300 includes a polymer electrolyte fuel cell 110 as a main body of the power generation unit. The polymer electrolyte fuel cell 110 includes a fuel gas passage 110a, an oxidant gas passage 110b, and a cooling water passage 110c. During the power generation operation of the fuel cell system 300, fuel gas is supplied to the fuel gas passage 110a. Air as the oxidant gas is supplied to the oxidant gas flow path 110b. The primary cooling water is supplied to the cooling water channel 110c.

  On the other hand, as shown in FIG. 5, the conventional fuel cell system 300 includes a cooling water tank 111, a cooling water pump 112, and a heat exchanger 113 in addition to the humidifier 107 described above. The cooling water tank 111 stores primary cooling water. The cooling water pump 112 feeds the primary cooling water by a predetermined water feeding means. As described above, the humidifier 107 humidifies air as an oxidant gas with a predetermined humidification configuration using primary cooling water. The heat exchanger 113 cools the primary cooling water by a predetermined heat exchange configuration using the secondary cooling water.

  The conventional fuel cell system 300 includes a radiator 114, a cooling water tank 115, and a cooling water pump 116 in addition to the condensers 108, 102, 104 and the heat exchanger 113 described above. The radiator 114 cools the secondary cooling water by a predetermined air cooling means. The cooling water tank 115 stores secondary cooling water. The cooling water pump 116 feeds the secondary cooling water by a predetermined water feeding means. As described above, the condensers 108, 102, and 104 convert water vapor into water (condensed water) by a predetermined cooling configuration using secondary cooling water. The heat exchanger 113 cools the primary cooling water by a predetermined heat exchange configuration using the secondary cooling water.

  In such a conventional fuel cell system 300, fuel gas and air as an oxidant gas are supplied from the reformer 101 and the air supply unit 106 to the fuel gas channel 110a and the oxidant gas channel 110b. Then, in the polymer electrolyte fuel cell 110, an electrochemical reaction using hydrogen contained in the fuel gas and oxygen contained in the air as the oxidant gas proceeds. As a result, the polymer electrolyte fuel cell 110 outputs desired power.

  During the power generation operation of the fuel cell system 300, the temperature of the polymer electrolyte fuel cell 110 rises due to reaction heat generated as the electrochemical reaction proceeds. Therefore, in this conventional fuel cell system 300, the cooling water pump 112 supplies the primary cooling water stored in the cooling water tank 111 to the cooling water flow path 110c of the polymer electrolyte fuel cell 110. Further, the secondary cooling water stored in the cooling water tank 115 is supplied to the heat exchanger 113 through the condensers 108, 102, and 104 by the cooling water pump 116. Thereby, the temperature of the polymer electrolyte fuel cell 110 is suitably maintained.

  The exhaust fuel gas and exhaust air discharged from the fuel gas channel 110 a and the oxidant gas channel 110 b of the polymer electrolyte fuel cell 110 are supplied to the condensers 102 and 108. The condensers 102 and 108 dehumidify exhaust fuel gas and exhaust air. The dehumidified exhaust fuel gas is burned in order to advance the steam reforming reaction in the reformer 101, further dehumidified by the condenser 104, and then exhausted outside the fuel cell system 300. The dehumidified exhaust air is exhausted to the outside of the fuel cell system 300. On the other hand, the water (condensed water) discharged from the condensers 108, 102, 104 is stored in the condensed water tanks 109, 103, 105.

  By the way, city gas and water are supplied to the reformer, and the reformer generates a fuel gas by advancing the steam reforming reaction, and the fuel gas is supplied to the polymer electrolyte fuel cell to generate power. In such a fuel cell system, the power generation performance of the polymer electrolyte fuel cell may deteriorate over time. The reason is that the performance of the membrane electrode assembly (commonly referred to as “MEA”) in the polymer electrolyte fuel cell deteriorates with time due to ammonia generated in the reformer.

  More specifically, city gas contains nitrogen which is irreversibly mixed from the atmosphere during the production process. The concentration of nitrogen contained in city gas is usually about 1% or less. When the city gas containing nitrogen is supplied to the reformer, hydrogen produced by the steam reforming reaction and nitrogen are combined to produce ammonia. That is, during the power generation operation of the fuel cell system, the reformer supplies a fuel gas containing ammonia at a concentration of several ppm to the polymer electrolyte fuel cell. Then, in the polymer electrolyte membrane in the membrane electrode assembly of the polymer electrolyte fuel cell, protons are replaced with ammonium ions over time. As a result of this substitution reaction, the proton exchange capacity of the polymer electrolyte membrane in the membrane electrode assembly gradually decreases with the elapse of the power generation operation time. That is, since the performance of the polymer electrolyte membrane decreases with time, the performance of the membrane electrode assembly decreases with time. The power generation performance of the polymer electrolyte fuel cell decreases with time due to a decrease in the performance of the membrane electrode assembly over time. Thus, when the fuel gas contains ammonia, the fuel cell system may cause reversible or irreversible power generation performance degradation over time.

  Therefore, various configurations of fuel cell systems have been proposed in which ammonia is removed from the fuel gas generated by the reformer, and the power generation performance of the polymer electrolyte fuel cell is prevented from decreasing with time.

  For example, when humidifying a fuel gas, a configuration of a fuel cell system is proposed in which ammonia contained in the fuel gas is dissolved in water, the ammonia is removed by an ion exchange cylinder, and the water is reused (for example, Patent Document 1).

  In addition, for example, a configuration of a fuel cell system that converts ammonia contained in fuel gas into nitrogen and hydrogen by electrolysis and a configuration of a fuel cell system that converts ammonia into nitrogen and hydrogen by electrophoresis are proposed. (For example, refer to Patent Documents 2 and 3).

According to the configuration of such a fuel cell system, ammonia is removed from the fuel gas generated by the reformer, and the fuel gas from which the ammonia has been removed is supplied to the fuel gas flow path of the polymer electrolyte fuel cell. The power generation performance of the polymer electrolyte fuel cell does not deteriorate over time. That is, since the power generation performance of the polymer electrolyte fuel cell is ensured for a long period of time, the power generation performance of the fuel cell system is ensured for a long period of time.
Japanese Patent Laid-Open No. 2003-31247 Japanese Patent Application No. 2004-145550 JP 2005-317419 A

  However, in the above conventional proposal, in the configuration in which the ammonia contained in the fuel gas is dissolved in water, the ammonia is removed by the ion exchange cylinder and the water is reused, it is necessary to periodically regenerate or replace the ion exchange cylinder. There is. Also, the price of the ion exchange cylinder is usually relatively high. Furthermore, the configuration of the ammonia removal mechanism using an ion exchange cylinder is usually a relatively complicated configuration. Therefore, in the configuration using this ion exchange cylinder, it is difficult to configure the fuel cell system at low cost and to suppress the running cost of the fuel cell system.

  In the conventional proposal, in the configuration in which ammonia contained in the fuel gas is converted into nitrogen and hydrogen by electrolysis or electrophoresis, it is necessary to dispose the electrolysis tank or the electrophoresis tank inside the fuel cell system. is there. These electrolysis and electrophoresis tanks are usually very expensive. Furthermore, the structure of the ammonia removal mechanism using these electrolysis tanks and electrophoresis tanks is usually a very complicated and large structure. In addition, in the configuration using these electrolysis tanks and electrophoresis tanks, large electric power is required to remove ammonia from the fuel gas.

  In other words, with the above conventional proposal, it is difficult to construct a realistic fuel cell system that can be spread to ordinary households, has low initial cost and maintenance cost, and is small and excellent in energy saving. there were.

  The present invention has been made in order to solve the above-described conventional problems, and has a low initial cost and a low maintenance cost, and includes a power-saving ammonia removing means having a simple and small-scale configuration. An object of the present invention is to provide a fuel cell system excellent in power generation efficiency capable of supplying power stably over a period of time.

  In order to solve the above-described conventional problems, a fuel cell system according to the present invention includes a reformer that supplies raw fuel and generates a fuel gas by a steam reforming reaction, and a fuel gas that is supplied by an electrochemical reaction. A polymer electrolyte fuel cell that generates electric power and discharges exhaust fuel gas, extracts ammonia from the fuel gas generated by the reformer, and extracts the fuel gas from which the ammonia has been extracted It further includes an ammonia pump that supplies the polymer electrolyte fuel cell and mixes the extracted ammonia with the exhaust fuel gas discharged from the polymer electrolyte fuel cell.

  With this configuration, the ammonia contained in the fuel gas is mixed with the exhaust fuel gas discharged from the polymer electrolyte fuel cell without being supplied to the polymer electrolyte fuel cell by the ammonia pump. As a result, the performance of the membrane electrode assembly of the polymer electrolyte fuel cell is suitably ensured over a long period of time, so that it is possible to provide a fuel cell system capable of stably supplying power over a long period of time. Become.

  In this case, the ammonia pump includes a cation exchanger, a pair of conductive catalyst layers that sandwich the cation exchanger, and a pair of conductive gas diffusion layers that sandwich the pair of conductive catalyst layers. And at least a gas diffusion electrode.

  With such a configuration, it is possible to provide a power-saving ammonia removal means having a simple and small-scale configuration, and therefore, it is possible to provide a fuel cell system with low initial cost and low maintenance cost and excellent power generation efficiency. It becomes possible.

  In this case, the cation exchanger is an organic cation exchanger.

  With such a configuration, an ammonia pump can be configured using a common organic cation exchanger that is already on the market without preparing a cation exchanger having a special configuration. This makes it possible to configure the ammonia pump at a low cost.

  In this case, the organic cation exchanger is a perfluorosulfonic acid membrane.

  With such a configuration, since the perfluorosulfonic acid membrane generally used as the electrolyte membrane of the polymer electrolyte fuel cell is used, the ammonia pump can be configured at a lower cost.

  In the above case, the cation exchanger is an inorganic cation exchanger.

  Even with such a configuration, an ammonia pump can be configured using a general inorganic cation exchanger that is already on the market without preparing a cation exchanger having a special configuration. This makes it possible to configure the ammonia pump at a low cost.

  In this case, the inorganic cation exchanger is a phosphoric acid aqueous solution layer.

  With such a configuration, a phosphoric acid aqueous solution layer that is generally used as an electrolyte layer of a phosphoric acid fuel cell is used, so that the ammonia pump can be configured at a lower cost.

  In the above case, the ammonia extraction side of the pair of conductive gas diffusion layers has a hydrophilic functional group.

  With this configuration, water vapor contained in the fuel gas is likely to condense on the ammonia extraction side in the pair of conductive gas diffusion layers. As a result, the ammonia contained in the fuel gas can be selectively and reliably trapped in the ammonia pump.

  In this case, the hydrophilic functional group is a sulfonic acid group.

  With this configuration, water vapor contained in the fuel gas can be reliably condensed on the ammonia extraction side of the pair of conductive gas diffusion layers.

  In this case, the hydrophilic functional group is a hydroxyl group.

  Even with such a configuration, it is possible to reliably condense the water vapor contained in the fuel gas on the ammonia extraction side in the pair of conductive gas diffusion layers.

  In the above case, the ammonia mixing side of the pair of conductive gas diffusion layers has a hydrophobic functional group.

  With this configuration, water containing ammonia is easily vaporized on the ammonia mixing side in the pair of conductive gas diffusion layers. Thereby, in the ammonia pump, the ammonia contained in the fuel gas can be reliably mixed with the exhaust fuel gas.

  In the above case, the apparatus further includes a power supply system which is supplied with electric power from the polymer electrolyte fuel cell and supplies driving power to the ammonia pump.

  With this configuration, it is not necessary to provide a power source or the like for supplying driving power to the ammonia pump, so that the fuel cell system can be reduced in size. In addition, the configuration of the fuel cell system can be simplified.

  Furthermore, in the above case, the polymer electrolyte fuel cell and the ammonia pump are integrated directly or indirectly.

  With such a configuration, since the polymer electrolyte fuel cell and the ammonia pump are directly or indirectly integrated, it is possible to provide a fuel cell system having the simplest and most compact configuration.

  The present invention is implemented in the means as described above, has low initial cost and maintenance cost, and is stable for a long period of time with a power-saving ammonia removing means having a simple and small-scale configuration. Thus, there is an effect that it is possible to provide a fuel cell system that can supply power and has excellent power generation efficiency.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
First, the configuration and operation of the fuel cell system according to Embodiment 1 of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram schematically showing a configuration of a fuel cell system according to Embodiment 1 of the present invention, which includes a polymer electrolyte fuel cell and a reformer. FIG. 1 shows only the components necessary for explaining the present invention, and the other components are not shown.

  As shown in FIG. 1, a fuel cell system 100 according to Embodiment 1 of the present invention includes a reformer 1, an ammonia pump 23 that characterizes the present invention, a condenser 4, a condensed water tank 5, and a condenser 6. And a condensed water tank 7. The reformer 1 generates a fuel gas containing hydrogen by advancing a steam reforming reaction using city gas and water as raw fuel. The ammonia pump 23 moves the ammonia contained in the fuel gas directly to the exhaust fuel gas side by using electrophoresis, and mixes the moved ammonia into the exhaust fuel gas. The internal configuration and operation of the ammonia pump 23 will be described in detail later. Moreover, the condensers 4 and 6 convert water vapor into water (condensed water) with a predetermined cooling configuration using secondary cooling water. The condensed water tanks 5 and 7 store water (condensed water). In the fuel cell system 100, the fuel gas discharge port of the reformer 1 and the fuel gas introduction port of the ammonia pump 23 are connected to each other by a pipe 2a. Further, a fuel gas discharge port of the ammonia pump 23 and one end of a fuel gas flow path 14a of the polymer electrolyte fuel cell 14 to be described later are connected to each other by a pipe 2b. The other end of the fuel gas passage 14a of the polymer electrolyte fuel cell 14 and the exhaust fuel gas inlet of the ammonia pump 23 are connected to each other by a pipe 3b. The exhaust fuel gas outlet of the ammonia pump 23 and the exhaust fuel gas inlet of the condenser 4 are connected to each other by a pipe 3a. Further, the exhaust fuel gas discharge port and the condensed water discharge port of the condenser 4 and the exhaust fuel gas introduction port of the reformer 1 and the condensed water introduction port of the condensed water tank 5 are connected to each other by a predetermined pipe. . Further, the exhaust combustion gas discharge port of the reformer 1 and the exhaust combustion gas introduction port of the condenser 6 are connected to each other by a predetermined pipe, and the condensed water discharge port of the condenser 6 and the condensed water of the condensed water tank 7 are connected. The introduction port is connected to each other by a predetermined pipe. Thereby, in the fuel cell system 100, a fuel gas supply / discharge system is configured.

  In addition, the fuel cell system 100 according to the first embodiment includes an air supply device 8, a humidifier 10, a condenser 12, and a condensed water tank 13. The air supply device 8 introduces air as an oxidant gas into the fuel cell system 100 from the atmosphere. The humidifier 10 humidifies air as an oxidant gas with a predetermined humidification configuration using primary cooling water. The condenser 12 converts water vapor into water (condensed water) with a predetermined cooling configuration using secondary cooling water. The condensed water tank 13 stores water (condensed water). In the fuel cell system 100, the air discharge port of the air supply device 8 and the air introduction port of the humidifier 10 are connected to each other by a pipe 9a. An air outlet of the humidifier 10 and one end of an oxidant gas flow path 14b of the polymer electrolyte fuel cell 14 described later are connected to each other by a pipe 9b. Further, the other end of the oxidant gas flow path 14 b of the polymer electrolyte fuel cell 14 and the exhaust air inlet of the condenser 12 are connected to each other by a pipe 11. Furthermore, the condensed water discharge port of the condenser 12 and the condensed water introduction port of the condensed water tank 13 are connected to each other by a predetermined pipe. Thus, in the fuel cell system 100, an oxidant gas supply / discharge system is configured.

  The fuel cell system 100 according to the first embodiment includes a polymer electrolyte fuel cell 14 as a main body of the power generation unit. The polymer electrolyte fuel cell 14 includes a fuel gas channel 14a, an oxidant gas channel 14b, and a cooling water channel 14c. During the power generation operation of the fuel cell system 100, fuel gas is supplied to the fuel gas passage 14a. Air as the oxidant gas is supplied to the oxidant gas flow path 14b. The primary cooling water is supplied to the cooling water passage 14c. Then, in the polymer electrolyte fuel cell 14, a predetermined electrochemical reaction using hydrogen contained in the fuel gas and oxygen contained in the air as the oxidant gas proceeds. Thereby, the polymer electrolyte fuel cell 14 outputs desired electric power.

  On the other hand, as shown in FIG. 1, the fuel cell system 100 according to the first embodiment includes a cooling water tank 15, a cooling water pump 16, and a heat exchanger 17 in addition to the humidifier 10 described above. ing. The cooling water tank 15 stores primary cooling water. The cooling water pump 16 feeds the primary cooling water by a predetermined water feeding means. As described above, the humidifier 10 humidifies air as an oxidant gas with a predetermined humidification configuration using primary cooling water. The heat exchanger 17 cools the primary cooling water by a predetermined heat exchange configuration using the secondary cooling water. In the fuel cell system 100, the cooling water discharge port of the cooling water tank 15 and the cooling water introduction port of the cooling water pump 16 are connected to each other by a pipe 18a. The cooling water discharge port of the cooling water pump 16 and one end of the cooling water flow path 14c of the polymer electrolyte fuel cell 14 are connected to each other by a pipe 18b. The other end of the cooling water flow path 14c of the polymer electrolyte fuel cell 14 and the cooling water inlet of the humidifier 10 are connected to each other by a pipe 18c. Furthermore, the cooling water discharge port of the humidifier 10 and the cooling water introduction port of the heat exchanger 17 are connected to each other by a pipe 18d. And the cooling water discharge port of the heat exchanger 17 and the cooling water introduction port of the cooling water tank 15 are mutually connected by the piping 18e. Thereby, in the fuel cell system 100, the circulation system of the primary cooling water is configured.

  Further, the fuel cell system 100 according to Embodiment 1 includes a radiator 19, a cooling water tank 20, and a cooling water pump 21 in addition to the condensers 12, 4, 6 and the heat exchanger 17 described above. I have. The radiator 19 cools the secondary cooling water by a predetermined air cooling means. The cooling water tank 20 stores secondary cooling water. The cooling water pump 21 feeds the secondary cooling water by a predetermined water feeding means. Note that, as described above, the condensers 12, 4, and 6 convert water vapor into water (condensed water) by a predetermined cooling configuration using secondary cooling water. Further, the heat exchanger 17 cools the primary cooling water by a predetermined heat exchange configuration using the secondary cooling water. In the fuel cell system 100, the cooling water discharge port of the cooling water tank 20 and the cooling water introduction port of the cooling water pump 21 are connected to each other by a pipe 22a. Further, the cooling water discharge port of the cooling water pump 21, the cooling water introduction port of the condenser 12, the cooling water discharge port of the condenser 12, the cooling water introduction port of the condenser 4, and the cooling water discharge of the condenser 4 The outlet, the cooling water inlet of the condenser 6, and the cooling water outlet of the condenser 6 and the cooling water inlet of the heat exchanger 17 are connected to each other by pipes 22b, 22c, 22d, and 22e, respectively. ing. Furthermore, the cooling water discharge port of the heat exchanger 17 and the cooling water introduction port of the radiator 19 are connected to each other by a pipe 22f. And the cooling water discharge port of the radiator 19 and the cooling water introduction port of the cooling water tank 20 are mutually connected by the piping 22g. Thus, in the fuel cell system 100, a secondary cooling water circulation system is configured.

  In the fuel cell system 100, during the power generation operation, the reformer 1 supplies the ammonia pump 23 with the fuel gas containing ammonia. Then, the ammonia pump 23 moves the ammonia contained in the fuel gas directly to the exhaust fuel gas side by utilizing electrophoresis, and mixes the moved ammonia with the exhaust fuel gas. On the other hand, the ammonia pump 23 supplies the fuel gas from which the ammonia has been removed to the fuel gas flow path 14 a of the polymer electrolyte fuel cell 14. That is, in the fuel cell system 100 according to the first embodiment, ammonia generated by the reformer 1 is discharged from the polymer electrolyte fuel cell 14 without being supplied to the polymer electrolyte fuel cell 14. It is supplied to the condenser 4 together with the exhausted fuel gas. Then, the ammonia that has passed through the condenser 4 and is supplied to the combustor (not shown in FIG. 1) built in the reformer 1 is burned together with the exhaust fuel gas in order to advance the steam reforming reaction.

  The fuel gas discharged from the ammonia pump 23 is supplied to the fuel gas channel 14 a of the polymer electrolyte fuel cell 14. At this time, the polymer electrolyte fuel cell 14 needs to be supplied with humidified fuel gas in view of its operating principle. However, according to the steam reforming reaction, part of the water supplied to the reformer 1 remains as steam in the fuel gas. That is, the fuel gas supplied from the reformer 1 is automatically humidified to a certain degree of humidification in the reformer 1. Therefore, normally, the fuel gas generated by the reformer 1 and passed through the ammonia pump 23 is directly supplied to the fuel gas flow path 14a of the polymer electrolyte fuel cell 14 without being particularly humidified. When it is necessary to compensate for the difference between the dew point of the fuel gas discharged from the ammonia pump 23 and the dew point of the fuel gas required by the polymer electrolyte fuel cell 14, in addition to the humidifier 10, the fuel gas A humidifier is provided separately to humidify.

  In place of the reformer 1, for example, when a hydrogen storage device such as a hydrogen cylinder is provided, it is not necessary to provide the ammonia pump 23. However, when constructing a fuel cell system as a practical continuous power generation facility, it is necessary to produce fuel gas using continuously available raw fuel such as city gas, propane gas, and gasoline. Therefore, normally, the reformer 1 that generates fuel gas by the steam reforming reaction is provided. When city gas is used as the raw fuel, ammonia is generated in the reformer 1, and therefore an ammonia pump 23 must be provided. This makes it possible to protect the polymer electrolyte fuel cell 14 from adverse effects caused by ammonia.

  On the other hand, in the fuel cell system 100, air as an oxidant gas is supplied from the air supply device 8 to the oxidant gas flow path 14 b of the polymer electrolyte fuel cell 14 during the power generation operation. At this time, the polymer electrolyte fuel cell 14 needs to be supplied with humidified air as in the case of the fuel gas. Therefore, in the fuel cell system 100, the air supplied from the air supply device 8 is humidified by the humidifier 10. The air humidified by the humidifier 10 is supplied to the oxidant gas flow path 14 b of the polymer electrolyte fuel cell 14. In addition, the humidifier 10 is a film | membrane humidifier normally provided with a water-permeable moisture-permeable film. The humidifier 10 humidifies the air supplied from the air supply device 8 to a desired humidity by using the primary cooling water discharged from the polymer electrolyte fuel cell 14 as a heat source and a water source.

  When air as a fuel gas and an oxidant gas is supplied to the fuel gas channel 14a and the oxidant gas channel 14b, in the polymer electrolyte fuel cell 14, hydrogen contained in the fuel gas and air as the oxidant gas are supplied. A predetermined electrochemical reaction using oxygen having proceeds. Thereby, the polymer electrolyte fuel cell 14 outputs desired electric power. At this time, the temperature of the polymer electrolyte fuel cell 14 increases due to the reaction heat generated as the predetermined electrochemical reaction proceeds. Therefore, in the fuel cell system 100, the primary cooling water stored in the cooling water tank 15 is continuously supplied to the cooling water flow path 14c of the polymer electrolyte fuel cell 14 by the water supply operation of the cooling water pump 16. . Thereby, the temperature of the polymer electrolyte fuel cell 14 is maintained at an appropriate temperature (usually 60 to 80 ° C.). Note that the primary cooling water whose temperature has risen discharged from the polymer electrolyte fuel cell 14 is used in the reformer 10 for humidifying the air supplied from the air supply device 8. The primary cooling water discharged from the humidifier 10 is cooled by the secondary cooling water in the heat exchanger 17 and then returned to the cooling water tank 15.

  In the fuel cell system 100, the secondary cooling water stored in the cooling water tank 20 is supplied to the condensers 12, 4, 6 by the water supply operation of the cooling water pump 21 in order to cool the primary cooling water. To the heat exchanger 17 continuously. Then, in the heat exchanger 17, the primary cooling water supplied from the humidifier 10 is cooled by the secondary cooling water supplied from the cooling water tank 20. The secondary cooling water whose temperature has been increased by heat exchange with the primary cooling water in the heat exchanger 17 is continuously supplied to the radiator 19 by the water supply operation of the cooling water pump 21. The radiator 19 cools the secondary cooling water by a predetermined air cooling means. Thereby, in the fuel cell system 100, the temperature of the primary cooling water and the secondary cooling water is maintained at an appropriate temperature. The secondary cooling water cooled by the radiator 19 is then returned to the cooling water tank 20.

  As described above, in the fuel cell system 100 according to Embodiment 1, the temperature of the polymer electrolyte fuel cell 14 is directly controlled by the primary cooling water so as to ensure the favorable power generation state. Further, in the fuel cell system 100, the temperature of the polymer electrolyte fuel cell 14 is indirectly controlled by the secondary cooling water so as to ensure a good power generation state. Thereby, in the fuel cell system 100, the power generation state of the polymer electrolyte fuel cell 14 is appropriately maintained.

  On the other hand, during the power generation operation of the fuel cell system 100, the exhaust fuel gas discharged from the polymer electrolyte fuel cell 14 is mixed with ammonia when passing through the ammonia pump 23 and then supplied to the condenser 4. . The exhaust fuel gas containing ammonia dehumidified by the condenser 4 is then supplied to the reformer 1. The exhaust fuel gas containing ammonia is combusted in a combustor (not shown) built in the reformer 1 in order to advance the steam reforming reaction. Exhaust combustion gas discharged from the reformer 1 is supplied to the condenser 6. The exhaust combustion gas dehumidified by the condenser 6 is exhausted to the outside of the fuel cell system 100. The condensed water discharged from the condensers 4 and 6 is stored in the condensed water tanks 5 and 7.

  Further, during the power generation operation of the fuel cell system 100, exhaust air discharged from the polymer electrolyte fuel cell 14 is supplied to the condenser 12. The exhaust air dehumidified by the condenser 12 is exhausted to the outside of the fuel cell system 100. The condensed water discharged from the condenser 12 is stored in the condensed water tank 13.

  The condensed water stored in the condensed water tanks 5, 7 and 13 is subjected to water purification treatment such as filtration and ion exchange in a condensed water regeneration system (not shown in FIG. 1). The condensed water subjected to this water purification treatment is supplied to the cooling water tank 15. The condensed water subjected to the water purification treatment is used as primary cooling water for cooling the polymer electrolyte fuel cell 14 or for humidifying the air supplied from the air supply device 8. Alternatively, the condensed water that has been subjected to the water purification treatment is used in the reformer 1 to advance the steam reforming reaction.

  Next, the configuration and operation of an ammonia pump characterizing the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a configuration diagram schematically showing the configuration of the ammonia pump according to Embodiment 1 of the present invention. Here, FIG. 2 (a) is an exploded perspective view of the ammonia pump according to Embodiment 1 of the present invention, and FIG. 2 (b) is a sectional view taken along the line IIb-IIb shown in FIG. 2 (a). is there. In FIG. 2, only the components necessary for explaining the characteristic configuration of the ammonia pump are shown, and the other components are not shown.

  As is apparent from FIGS. 2A and 2B, the ammonia pump 23 has a structure of a unit cell (usually, simply “stack”) of a general polymer electrolyte fuel cell stack (usually simply “stack”). This is basically the same as the configuration of “cell”. That is, as shown in FIGS. 2A and 2B, the ammonia pump 23 according to Embodiment 1 of the present invention includes a conductive separator 23a, a membrane electrode assembly 23b, and a conductive separator 23c. ing. Each of the conductive separator 23a, the membrane electrode assembly 23b, and the conductive separator 23c has a substantially flat plate shape. The conductive separator 23a, the membrane electrode assembly 23b, and the conductive separator 23c each have the same rectangular shape when viewed from the main surface A side of the ammonia pump 23. The conductive separator 23a, the membrane electrode assembly 23b, and the conductive separator 23c are stacked in this order, and are fastened by a predetermined fastening means to constitute the ammonia pump 23.

  Specifically, the conductive separators 23a and 23c include a zigzag fuel gas passage Pa and a zigzag exhaust fuel gas passage Pb. In FIG. 2 of the fuel gas flow path Pa, the pipe 2a is connected to the lower side so as to be able to supply the fuel gas, and in FIG. Further, in FIG. 2 of the exhaust fuel gas flow path Pb, the pipe 3b is connected so as to be able to supply the exhaust fuel gas, and in FIG. 2 of the exhaust fuel gas flow path Pb, the pipe 3a is connected so that the exhaust fuel gas can be discharged downward. Has been. The fuel gas flow path Pa and the exhaust fuel gas flow path Pb are separated from each other by the membrane electrode assembly 23b in the completed ammonia pump 23. Therefore, in the ammonia pump 23, even when the fuel gas is supplied to the fuel gas passage Pa and the exhaust fuel gas is supplied to the exhaust fuel gas passage Pb, the fuel gas and the exhaust fuel gas are mixed. Never happen.

  On the other hand, as shown in FIG. 2B, the membrane electrode assembly 23b includes a single cation exchanger a and a pair of gas diffusion electrodes b and c.

  The cation exchanger a is composed of an organic cation exchanger or an inorganic cation exchanger. Here, as the organic cation exchanger, for example, a perfluorosulfonic acid membrane is used. Moreover, as an inorganic cation exchanger, a phosphoric acid aqueous solution layer is used, for example.

  The gas diffusion electrode b includes a conductive catalyst layer b1 mainly made of platinum carbon and a conductive gas diffusion layer b2 made of carbon fibers having electrical conductivity and gas permeability. Similarly, the gas diffusion electrode c includes a conductive catalyst layer c1 mainly made of platinum carbon and a conductive gas diffusion layer c2 made of carbon fibers having electrical conductivity and gas permeability. Here, it is more desirable that the conductive gas diffusion layer b2 is subjected to a hydrophilic treatment. Examples of the hydrophilic treatment include hydrophilic treatment such as plasma treatment and activation treatment. By these hydrophilic treatments, hydrophilic functional groups represented by hydroxyl groups and the like are constructed on the surface of the conductive gas diffusion layer b2. In order to impart hydrophilicity to the conductive gas diffusion layer b2, the conductive gas diffusion layer b2 may be impregnated with a perfluorosulfonic acid polymer. By this impregnation treatment, the conductive gas diffusion layer b2 becomes a conductive gas diffusion layer having a sulfonic acid group.

  Further, it is more desirable that the conductive gas diffusion layer c2 is subjected to a hydrophobic treatment. By this hydrophobic treatment, a hydrophobic functional group represented by a methyl group or the like is constructed on the surface of the conductive gas diffusion layer c2. When the conductive gas diffusion layer c2 is made of carbon fiber impregnated with polytetrafluoroethylene, the hydrophobic treatment can be omitted. This is because the conductive gas diffusion layer c2 made of polytetrafluoroethylene and carbon fiber has water repellency.

  And the gas diffusion electrode b is joined to the predetermined area | region in one main surface of the cation exchanger a in the state which the electroconductive catalyst layer b1 contacted the cation exchanger a. In addition, a gas diffusion electrode c is joined to a predetermined region on the other main surface of the cation exchanger a in a state where the conductive catalyst layer c1 is in contact with the cation exchanger a. Thereby, in the ammonia pump 23, the membrane electrode assembly 23b is comprised.

  In the present embodiment, the conductive separators 23a and 23c of the ammonia pump 23 are each composed of a conductive material mainly composed of metal or carbon, similarly to the configuration of the conductive separator in the polymer electrolyte fuel cell 14. Has been. The membrane electrode assembly 23 b has the same configuration as the membrane electrode assembly in the polymer electrolyte fuel cell 14. In the present embodiment, the periphery of the cation exchanger a in the membrane electrode assembly 23b is sandwiched between the peripheral edges of the conductive separators 23a and 23c, and the gas diffusion electrodes b and c in the membrane electrode assembly 23b are predetermined. The region is sandwiched in a conductive state by a predetermined region of the conductive separators 23a and 23c, and the ammonia pump 23 is configured.

  In the ammonia pump 23, the fuel gas containing ammonia is supplied from the reformer 1 to the fuel gas flow path Pa during the power generation operation of the fuel cell system 100. On the other hand, the exhaust fuel gas discharged from the fuel gas passage 14 a of the polymer electrolyte fuel cell 14 is supplied to the exhaust fuel gas passage Pb of the ammonia pump 23. At this time, as shown in FIG. 2B, a voltage is applied between the conductive separator 23a and the conductive separator 23c of the ammonia pump 23. In the present embodiment, driving power for driving the ammonia pump 23 is supplied from the polymer electrolyte fuel cell 14. That is, the fuel cell system 100 according to the present embodiment further includes a power supply system that is supplied with power from the polymer electrolyte fuel cell 14 and supplies the driving power to the ammonia pump 23. The voltage value applied between the conductive separator 23a and the conductive separator 23c of the ammonia pump 23 is approximately 1V, although it varies depending on the film thickness of the cation exchanger a. That is, the ammonium ion can be electrophoresed in the cation exchanger a of the ammonia pump 23, while a predetermined voltage that does not cause electrolysis of water in the cation exchanger a is conductive with the conductive separator 23a. Applied between the conductive separator 23c.

  Then, in the ammonia pump 23, dissolution of the ammonia contained in the fuel gas into the water proceeds in the conductive gas diffusion layer b2 of the membrane electrode assembly 23b in which the water vapor contained in the fuel gas is condensed to be in a substantially wet state. To do. At this time, since ammonia is very easily dissolved in water, the ammonia contained in the fuel gas is selectively dissolved in water. That is, ammonia contained in the fuel gas is selectively trapped in the conductive gas diffusion layer b2 of the ammonia pump 23. On the other hand, the solubility of hydrogen in water is very low. Therefore, the hydrogen contained in the fuel gas is discharged from the ammonia pump 23 without being almost dissolved in water. Then, when ammonia contained in the fuel gas is dissolved in water, ammonium ions and hydroxide ions are generated as shown in chemical formula (1).

_{NH 3 + H 2 O → NH} 4 + + OH - ··· (1)
On the other hand, on the conductive catalyst layer b1 in the membrane electrode assembly 23b of the ammonia pump 23, as shown in the chemical formula (2), the hydrogen dissociation reaction proceeds.

(1/2) H ₂ → H ⁺ + e ⁻ (2)
Further, on the fuel gas flow path Pa side of the membrane electrode assembly 23b in the ammonia pump 23, as shown in the chemical formula (3), a neutralization reaction between protons and hydroxide ions proceeds.

H ⁺ + OH ⁻ → H ₂ O (3)
That is, in the ammonia pump 23, on the fuel gas flow path Pa side of the membrane electrode assembly 23b, as shown in FIG. 2B, a chemical reaction apparently expressed by the chemical formula (4) proceeds.

NH ₃ + (1/2) H ₂ → NH ₄ ⁺ + e ⁻ (4)
Depending on the configuration of the fuel cell system 100, the water vapor contained in the fuel gas may condense in the conductive gas diffusion layer b2 of the gas diffusion electrode b in the ammonia pump 23, so that the fuel supplied to the polymer electrolyte fuel cell 14 Gas dew point may be reduced. In this case, a humidifier may be disposed between the ammonia pump 23 and the polymer electrolyte fuel cell 14 in order to appropriately compensate for the dew point of the fuel gas.

  In general, in the cation exchanger a, the affinity for ammonium ions is much greater than the affinity for protons. Therefore, in the ammonia pump 23, ammonia (ammonium ions) dissolved in water on the fuel gas flow path Pa side of the membrane electrode assembly 23b is easily taken into the cation exchanger a. The captured ammonium ions sequentially replace the terminal groups of the cation exchanger a and reach the exhaust fuel gas flow path Pb side of the membrane electrode assembly 23b in the ammonia pump 23. Then, in the ammonia pump 23, as shown in the chemical formula (5), the reduction reaction of ammonium ions proceeds in the conductive catalyst layer c1 in the gas diffusion electrode c of the membrane electrode assembly 23b. Thereby, ammonium ion is returned to ammonia.

NH ₄ ⁺ + e ⁻ → NH ₃ + (1/2) H ₂ (5)
In the ammonia pump 23, the ammonia generated in the conductive catalyst layer c1 in the gas diffusion electrode c of the membrane electrode assembly 23b moves to the conductive gas diffusion layer c2 adjacent to the conductive catalyst layer c1. Then, in the ammonia pump 23, the ammonia moved to the conductive gas diffusion layer c2 is mixed with the exhaust fuel gas supplied to the exhaust fuel gas flow path Pb. The exhaust fuel gas containing ammonia is then discharged from the exhaust fuel gas flow path Pb of the ammonia pump 23. The exhaust fuel gas containing ammonia discharged from the ammonia pump 23 is supplied to the condenser 4 and dehumidified in the condenser 4. The exhausted fuel gas containing the dehumidified ammonia is supplied to the combustor of the reformer 1. The exhaust fuel gas containing ammonia is combusted in the combustor of the reformer 1 in order to advance the steam reforming reaction.

  As shown in the chemical formula (2), in the ammonia pump 23, a part of hydrogen contained in the fuel gas is consumed as the hydrogen dissociation reaction proceeds. In the ammonia pump 23, as shown in the chemical formula (5), hydrogen is generated simultaneously with the generation of ammonia. The generated hydrogen is supplied to the condenser 4 together with ammonia and exhaust fuel gas, and then burned in the combustor of the reformer 1. Therefore, at first glance, according to the present invention, the power generation efficiency of the fuel cell system 100 seems to deteriorate. However, the concentration of ammonia extracted from the fuel gas in the ammonia pump 23 is about several ppm. Therefore, the consumption of hydrogen in the ammonia pump 23 is very small. Therefore, the power generation efficiency of the fuel cell system 100 is not substantially deteriorated.

  As described above, in the present invention, the ammonia generated in the reformer 1 is trapped continuously and selectively by the ammonia pump 23. The ammonia produced by the reformer 1 is mixed with the exhaust fuel gas discharged from the polymer electrolyte fuel cell 14 without being supplied to the polymer electrolyte fuel cell 14. That is, in the present invention, the ammonia pump 23 functions as an ammonia pump as an electrochemical chemical pump. As a result, according to the present invention, the performance of the polymer electrolyte membrane provided in the polymer electrolyte fuel cell 14 can be suitably maintained over a long period of time. As a result, the power generation performance of the polymer electrolyte fuel cell 14 is suitably maintained over a long period of time, so that the power generation performance of the fuel cell system 100 is suitably maintained over a long period of time.

  In the present invention, the ammonia pump 23 is basically configured in the same manner as the unit cell of the polymer electrolyte fuel cell 14. For this reason, the ammonia pump 23 can be configured in a simple manner, and power consumption when ammonia is extracted from the fuel gas and mixed with the exhausted fuel gas can be suppressed. In addition, according to the present invention, it is not necessary to periodically regenerate the ammonia pump 23. Further, according to the present invention, it is not necessary to periodically replace the ammonia pump 23. As a result, the ammonia pump 23 can be configured at low cost, and the running cost of the ammonia pump 23 can be suppressed. That is, the fuel cell system 100 can be provided at a low cost and the running cost can be suppressed.

  Furthermore, according to the present invention, the ammonia pump 23 can be reduced in size. Therefore, it is possible to prevent the fuel cell system 100 from becoming large. As a result, the fuel cell system 100 can be widely spread to general households. In addition, according to the present invention, the ammonia pump 23 can be provided also in the fuel cell system 100 such as mobile and portable. Thereby, the convenience of the fuel cell system 100 can be further improved.

  The configuration of the ammonia pump 23 is not limited to the configuration shown in FIG. That is, the ammonia pump 23 is appropriately configured according to an index such as the nitrogen content concentration of the city gas supplied to the reformer 1 and the rated output of the fuel cell system 100. With this configuration, it is possible to obtain the same effect as that obtained by the present embodiment.

(Embodiment 2)
FIG. 3 is a block diagram schematically showing a configuration of a fuel cell system according to Embodiment 2 of the present invention, which includes a polymer electrolyte fuel cell and a reformer. In FIG. 3, only the components necessary for explaining the present invention are shown, and the other components are not shown. In FIG. 3, the same components as those of the fuel cell system 100 according to Embodiment 1 are denoted by the same reference numerals.

  As shown in FIG. 3, the fuel cell system 200 according to Embodiment 2 of the present invention basically has the same configuration as the configuration of the fuel cell system 100 according to Embodiment 1. However, the configuration of the fuel cell system 200 is different from the configuration of the fuel cell system 100 in that the ammonia pump 23 and the polymer electrolyte fuel cell 14 are integrated. In other respects, the configuration and operation of the fuel cell system 200 and the configuration and operation of the fuel cell system 100 are the same.

  Specifically, the fuel cell system 200 includes a polymer electrolyte fuel cell 14 and an ammonia pump 23. In the fuel cell system 200, the polymer electrolyte fuel cell 14 and the ammonia pump 23 are integrated. In the fuel cell system 200, the fuel gas discharge port of the reformer 1 and the fuel gas introduction port of the ammonia pump 23 are connected to each other by a pipe 2. Further, the exhaust fuel gas outlet of the ammonia pump 23 and the exhaust fuel gas inlet of the condenser 4 are connected to each other by a pipe 3. Note that one end of the fuel gas flow path 14 a of the polymer electrolyte fuel cell 14 is directly connected to the fuel gas discharge port of the ammonia pump 23. The other end of the fuel gas passage 14 a of the polymer electrolyte fuel cell 14 is directly connected to the exhaust fuel gas inlet of the ammonia pump 23.

  FIG. 4 is a configuration diagram schematically showing a configuration of a joined body of an ammonia pump and a polymer electrolyte fuel cell in the fuel cell system according to Embodiment 2 of the present invention. Here, FIG. 4A is an external perspective view of a joined body of an ammonia pump and a polymer electrolyte fuel cell according to Embodiment 2 of the present invention. FIG. 4B is a cross-sectional view taken along line IVb-IVb shown in FIG. In FIG. 4, only the components necessary for explaining the characteristic configuration of the assembly of the ammonia pump and the polymer electrolyte fuel cell are shown, and the other components are not shown. is doing. In FIG. 4, the same components as those of the fuel cell system 100 according to Embodiment 1 are denoted by the same reference numerals.

  As shown in FIGS. 4 (a) and 4 (b), in the present embodiment, the configuration of the ammonia pump 23 is the same as that of the unit cell of the polymer electrolyte fuel cell 14, and an appropriate By the design, a joined body 24 including the ammonia pump 23 and the polymer electrolyte fuel cell 14 is configured. In this joined body 24, the polymer electrolyte fuel cell 14 includes a polymer electrolyte fuel cell stack 14d, current collecting plates 14e and 14e, and fastening end plates 14f and 14f. In the joined body 24, an ammonia pump 23 and a fastening end plate 14 g are disposed adjacent to the polymer electrolyte fuel cell 14. In the present embodiment, the fastening end plate 14g, the ammonia pump 23, and the polymer electrolyte fuel cell 14 are stacked in that order, and fastened by a predetermined fastening means to constitute the joined body 24. .

  In the present embodiment, the embodiment in which the ammonia pump 23 and the polymer electrolyte fuel cell 14 are directly integrated has been described. However, the present invention is not limited to this embodiment. For example, in order to thermally separate the ammonia pump 23 and the polymer electrolyte fuel cell 14, they may be integrated indirectly via a predetermined heat insulating plate. Further, for example, in order to control the thermal conductivity from the polymer electrolyte fuel cell 14 to the ammonia pump 23, they may be integrated indirectly via a predetermined buffer plate.

  Even in such a configuration, the ammonia generated in the reformer 1 is continuously and selectively trapped by the ammonia pump 23. The ammonia produced by the reformer 1 is mixed with the exhaust fuel gas discharged from the polymer electrolyte fuel cell 14 without being supplied to the polymer electrolyte fuel cell 14. As a result, the performance of the polymer electrolyte membrane provided in the polymer electrolyte fuel cell 14 can be suitably maintained over a long period of time. As a result, the power generation performance of the polymer electrolyte fuel cell 14 is suitably maintained over a long period of time, so that the power generation performance of the fuel cell system 200 is suitably maintained over a long period of time.

  Further, according to the present embodiment, since the ammonia pump 23 and the polymer electrolyte fuel cell 14 are integrated, the fuel cell system 200 can be configured most compactly. As a result, the fuel cell system 200 can be further reduced in size.

  Furthermore, according to the present embodiment, since the ammonia pump 23 and the polymer electrolyte fuel cell 14 are integrated, the ammonia pump 23 can be heated to an appropriate temperature by the polymer electrolyte fuel cell 14. . Thereby, the ammonia contained in the fuel gas can be effectively trapped in the ammonia pump 23. Therefore, the power generation performance of the fuel cell system 200 can be suitably maintained for a longer period of time.

  Other points are the same as those in the first embodiment.

  The fuel cell system according to the present invention has a low initial cost and a low maintenance cost, and stably supplies power over a long period of time with a power-saving ammonia removing means having a simple and small-scale configuration. As a fuel cell system with excellent power generation efficiency, it has industrial applicability.

FIG. 1 is a block diagram schematically showing a configuration of a fuel cell system according to Embodiment 1 of the present invention, which includes a polymer electrolyte fuel cell and a reformer. FIG. 2 is a configuration diagram schematically showing the configuration of the ammonia pump according to Embodiment 1 of the present invention. FIG. 2A is an exploded perspective view of the ammonia pump according to Embodiment 1 of the present invention. FIG. 2B is a cross-sectional view taken along the line IIb-IIb shown in FIG. FIG. 3 is a block diagram schematically showing a configuration of a fuel cell system according to Embodiment 2 of the present invention, which includes a polymer electrolyte fuel cell and a reformer. FIG. 4 is a configuration diagram schematically showing a configuration of a joined body of an ammonia pump and a polymer electrolyte fuel cell in the fuel cell system according to Embodiment 2 of the present invention. FIG. 4 (a) is an external perspective view of a joined body of an ammonia pump and a polymer electrolyte fuel cell according to Embodiment 2 of the present invention. FIG. 4B is a cross-sectional view taken along line IVb-IVb shown in FIG. FIG. 5 is a block diagram schematically showing a configuration of a conventional fuel cell system including a polymer electrolyte fuel cell and a reformer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reformer 2 Piping 2a, 2b Piping 3 Piping 3a, 3b Piping 4 Condenser 5 Condensed water tank 6 Condenser 7 Condensed water tank 8 Air supply device 9a, 9b Piping 10 Humidifier 11 Piping 12 Condenser 13 Condensed water tank DESCRIPTION OF SYMBOLS 14 Polymer electrolyte fuel cell 14a Fuel gas flow path 14b Oxidant gas flow path 14c Cooling water flow path 14d Polymer electrolyte fuel cell laminated body 14e Current collecting plate 14f Fastening end plate 14g Fastening end plate 15 Cooling water tank 16 Cooling water Pump 17 Heat exchanger 18a to 18e Piping 19 Radiator 20 Cooling water tank 21 Cooling water pump 22a to 22g Piping 23 Ammonia pump 23a Conductive separator 23b Membrane electrode assembly 23c Conductive separator 24 Junction 101 Reforming device 102 Condenser 103 Condensed water tank 104 Condenser 105 Condensed water tank 10 6 Air Supply Device 107 Humidifier 108 Condenser 109 Condensed Water Tank 110 Polymer Electrolyte Fuel Cell 110a Fuel Gas Channel 110b Oxidant Gas Channel 110c Cooling Water Channel 111 Cooling Water Tank 112 Cooling Water Pump 113 Heat Exchanger 114 Heat Dissipation 115 Cooling water tank 116 Cooling water pump 100-300 Fuel cell system A Main surface Pa Fuel gas flow path Pb Exhaust fuel gas flow path a Cation exchanger b Gas diffusion electrode b1 Conductive catalyst layer b2 Conductive gas diffusion layer c Gas diffusion electrode c1 conductive catalyst layer c2 conductive gas diffusion layer

Claims (12)

A reformer for supplying raw fuel and generating fuel gas by a steam reforming reaction;
A polymer electrolyte fuel cell that is supplied with fuel gas, generates electric power by an electrochemical reaction, and discharges exhaust fuel gas; and
At least,
Ammonia is extracted from the fuel gas generated by the reformer, the fuel gas from which the ammonia has been extracted is supplied to the polymer electrolyte fuel cell, and the extracted ammonia is extracted from the polymer electrolyte fuel cell. A polymer electrolyte fuel cell system further comprising an ammonia pump for mixing with the discharged exhaust gas.   The ammonia pump has a cation exchanger, a pair of conductive catalyst layers that sandwich the cation exchanger, and a pair of conductive gas diffusion layers that sandwich the pair of conductive catalyst layers. And a polymer electrolyte fuel cell system according to claim 1.   The polymer electrolyte fuel cell system according to claim 2, wherein the cation exchanger is an organic cation exchanger.   The polymer electrolyte fuel cell system according to claim 3, wherein the organic cation exchanger is a perfluorosulfonic acid membrane.   The polymer electrolyte fuel cell system according to claim 2, wherein the cation exchanger is an inorganic cation exchanger.   The polymer electrolyte fuel cell system according to claim 5, wherein the inorganic cation exchanger is a phosphoric acid aqueous solution layer.   The polymer electrolyte fuel cell system according to claim 2, wherein the ammonia extraction side of the pair of conductive gas diffusion layers has a hydrophilic functional group.   The polymer electrolyte fuel cell system according to claim 7, wherein the hydrophilic functional group is a sulfonic acid group.   The polymer electrolyte fuel cell system according to claim 7, wherein the hydrophilic functional group is a hydroxyl group.   The polymer electrolyte fuel cell system according to claim 2, wherein the ammonia mixing side of the pair of conductive gas diffusion layers has a hydrophobic functional group.   The polymer electrolyte fuel cell system according to claim 1, further comprising a power supply system that is supplied with electric power from the polymer electrolyte fuel cell and supplies driving power to the ammonia pump. The polymer electrolyte fuel cell system according to claim 1, wherein the polymer electrolyte fuel cell and the ammonia pump are integrated directly or indirectly.

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