JP2013020865A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system that prevents deposition of water impurities on positions, where water is evaporated, in a preheat evaporator 7 of a hydrogen generation device 2, and thus prevents clogging of the preheat evaporator 7, so as to allow stable continued operation.SOLUTION: A fuel cell system includes a water distillation section 34 that heats and distillates water to be supplied to a reforming water tank 28; and a water supply path 31 that connects the water distillation section 34 and the reforming water tank 28. The water to be supplied to the reforming tank 28 is firstly heated and distillated in the water distillation section 34 so as to remove water impurities, such as silica, potassium, calcium, iron, and the like. The water is then passed through the water supply path 31, stored in the reforming tank 28, and finally supplied to the preheat evaporator 7. Thus, the impurities, such as silica, potassium, calcium, iron, and the like, are prevented from being deposited in the preheat evaporator 7.

Description

  The present invention relates to a fuel cell system provided with a hydrogen generator by a reforming reaction in which a reforming fuel and water are reacted to generate a reformed gas.

  The hydrogen generator uses a reforming fuel (raw material) containing at least hydrocarbons composed of carbon and hydrogen such as city gas and LP gas, and water to reform steam in a reforming reaction section having a reforming catalyst layer inside. A hydrogen-containing gas is produced by a quality reaction. The fuel cell system includes a hydrogen generator and supplies the generated hydrogen-containing gas (hereinafter referred to as reformed gas) to the fuel cell to generate power.

  Water is desirably supplied to the reforming catalyst layer in the form of water vapor, and it is desirable to supply water to a preheating evaporator heated from a heat source to generate water vapor.

  An example of a device having a preheat evaporator that efficiently evaporates water is a fuel reformer 100 shown in FIG. The fuel reformer 100 includes a combustion cylinder 112 disposed on a central axis thereof and a burner 114 that forms a flame. A reforming reaction portion 128 filled with a reforming catalyst is provided at the lower end of the annular space between the coaxially arranged inner cylinder 120 and the upper partition cylinder 124a, and the annular space between the inner cylinder 120 and the upper partition cylinder 124a. A raw fuel gas supply port 125 for supplying reforming water and raw fuel gas (raw material) together is connected to the upper end of the space. Further, the fuel reformer 100 is provided with a spiral guide 126 that is a spirally formed plate or rod-like member on the outer wall of the inner cylinder 120 facing the upper partition cylinder 124a. The reforming water supplied from the fuel gas supply port 125 has a preheat evaporator configured to be heated and vaporized while flowing along the surface of the spiral guide and in contact with the surface of the inner cylinder. (For example, refer to Patent Document 1).

JP 2007-15911 A

  However, the preheating evaporator of the conventional fuel cell system has the following problems.

  In the preheat evaporator having the spiral path described above, the water mixed with the hydrocarbon as the raw fuel passes through the spiral guide provided on the outer wall of the inner cylinder. At this time, as the water passes on the spiral guide, the heat is collected and gradually evaporated, and it finishes passing through the path of the spiral path that can obtain the amount of heat that the water can completely evaporate. By the time it reaches the position, it is designed so that the water will eventually evaporate.

Generally, water for reforming is used while being circulated in the process of reforming reaction and power generation reaction in the fuel cell system. However, if the amount of water released into the atmosphere during circulation increases, if there is an abnormality in the water circulation or supply path, or if water is frequently replenished or replaced during parts replacement maintenance, the fuel It is necessary to supply additional tap water into the battery system. Therefore, tap water containing impurities such as silica, potassium, calcium, and iron is supplied to the preheating evaporator. When tap water is supplied to the preheating evaporator, these impurities may be deposited in the steam path of the preheating evaporator to block the path, making it difficult for the raw material and water (steam) to flow. In this case, a predetermined reformed gas cannot be generated due to the steam reforming reaction in the reforming reaction section, and the operation of the fuel cell system may not be continued.

  The present invention has been made in view of the above-described conventional problems, and even when it is necessary to additionally supply tap water into the fuel cell system, impurities contained in the water supplied to the preheating evaporator are present. An object of the present invention is to provide a fuel cell system capable of suppressing the precipitation and clogging of the preheating evaporator and continuing the stable operation.

  In order to solve the above-described conventional problems, a fuel cell system according to the present invention generates steam from water using a combustor that generates combustion gas and the heat of the combustion gas, and the generated steam and supplied raw material. And a reforming reaction section that is disposed downstream of the preheating evaporator and is heated using the heat of the combustion gas to generate a hydrogen-containing gas from the raw material and steam by a steam reforming reaction. A hydrogen generating device, a fuel cell that generates electricity by reacting a hydrogen-containing gas and oxygen, a reforming water tank that stores water, a reforming water tank, and a water supply path that connects the preheat evaporator and a water supply path A water reforming unit for supplying water, a water distilling unit for heating and distilling water to be supplied to the reforming water tank, and a water replenishment path communicating the water distilling unit and the reforming water tank. Is.

  As a result, the water supplied to the reforming water tank is heated and distilled in the water distillation section to remove impurities such as silica, potassium, calcium and iron in the water, and then the water is supplied to the reforming water tank through the water supply path. Since this water is supplied to the preheating evaporator of the hydrogen generator by the reforming water supply unit, precipitation of impurities such as silica, potassium, calcium and iron in the water occurs at the water vapor evaporation position of the preheating evaporator. This is to prevent this.

  In the fuel cell system of the present invention, water supplied to the preheating evaporator of the hydrogen generator is heated and distilled in a water distillation section to remove impurities such as silica, potassium, calcium and iron in the water, and then a water supply path Is stored in the reforming water tank, and is supplied to the preheating evaporator of the hydrogen generator by the reforming water supply unit. Therefore, it can suppress that the impurity in water precipitates in a preheating evaporator, and can prevent that a preheating evaporator is blocked. Moreover, the fuel cell system which continues a stable driving | operation can be provided.

1 is a block diagram showing a configuration of a fuel cell system according to Embodiment 1 of the present invention. FIG. 3 is a block diagram showing a configuration of a fuel cell system according to Embodiment 2 of the present invention. Block diagram showing the configuration of a conventional fuel cell system

  The fuel cell system of the present invention includes a combustor that generates combustion gas, steam generated from water using heat of the combustion gas, a preheat evaporator that mixes the generated steam and the supplied raw material, and A hydrogen generator having a reforming reaction section that is disposed downstream of the preheating evaporator and is heated using the heat of the combustion gas to generate a hydrogen-containing gas from a raw material and steam by a steam reforming reaction; A fuel cell that generates electricity by reacting a hydrogen-containing gas and oxygen generated by the hydrogen generator, a reforming water tank that stores water to be supplied to the preheating evaporator, and the reforming water tank and the preheating evaporator communicate with each other. Water distillation path that is provided on the water supply path and that supplies water to the preheat evaporator, and water distillation that heats and distills the water supplied to the reformed water tank Part and the water Water supply path communicating the engaging portion and the reforming water tank, but with a.

This heats and distills the water supplied to the reformed water tank in the water distillation unit,
After removing impurities such as potassium, calcium, and iron, water can be stored in the reformed water tank via the water replenishment path, and this water can be supplied to the preheating evaporator of the hydrogen generator by the reformed water supply unit. Therefore, it is possible to suppress the precipitation of impurities in the water at the location where water has evaporated in the preheating evaporator, and it is possible to prevent the preheating evaporator from being clogged. Further, it is possible to provide a fuel cell system capable of continuing stable operation.

  The present invention also provides combustion exhaust gas discharged from a combustor, anode off-gas after power generation discharged from an outlet on the fuel electrode side of the fuel cell, and cathode off-gas after power generation discharged from the air electrode side of the fuel cell. A condenser for condensing moisture in at least one of the gases, and a condensed water recovery path for supplying condensed water recovered from the condenser to the reforming water tank.

  Thereby, the water produced | generated in the process of an electric power generation reaction can be collect | recovered, can be used for a reforming reaction, and can be used, circulating in a fuel cell system. Therefore, the amount of water released outside the fuel cell system can be reduced, and the number of water replenishments can be reduced.

  Therefore, since the supply of water containing impurities such as silica, potassium, calcium and iron is reduced from the water pipe as the water supply source, the energy for heating and distilling the water in the water distillation section can be reduced. . Moreover, it is possible to suppress the precipitation of impurities in the water at the location where the water is evaporated in the preheating evaporator by circulating the water with less impurities.

  Moreover, this invention may be provided with the water purification | cleaning part in the supply path | route between the reforming water tank or the preheat evaporator of a hydrogen production | generation apparatus in a reforming water tank.

  As a result, ions such as chlorine that affect the catalyst dissolved in the water supplied to the hydrogen generator can be removed and supplied. Therefore, it is possible to increase the durability of the catalyst and to suppress the precipitation of impurities in the water at the location where the water has evaporated in the preheating evaporator.

  Furthermore, since the water supplied to the reforming water tank is heated and distilled in the water distillation section and then stored in the reforming water tank, the life of the water purification section can be extended and the replacement frequency can be reduced.

  Further, the present invention provides a combustion gas path in which a preheating evaporator is formed so that combustion gas flows along an inner cylinder of different diameters arranged concentrically with a combustor, and an outer cylinder and an inner surface of the inner cylinder. A water path defining portion that circulates the water along the outer surface of the inner cylinder in a part of the annular space between the cylinder and the outer cylinder, and the reforming reaction section is an annular space on the downstream side of the preheat evaporator It may be configured to be filled with a reforming catalyst.

  As a result, the preheating evaporator can be prevented from becoming clogged in a configuration in which the heating combustor, the combustion gas path, the preheating evaporator, and the reforming reaction unit are integrated, so that the preheating evaporator can be reduced in size and hydrogen can be generated. The entire apparatus can be made compact.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, the same or corresponding elements are denoted by the same reference numerals throughout all the drawings, and redundant description thereof is omitted.

(Embodiment 1)
FIG. 1 is a block diagram showing an outline of a fuel cell system according to Embodiment 1 of the present invention.

Hereinafter, an embodiment of a fuel cell system according to the present invention will be described. In FIG.
The fuel cell system includes a fuel cell 1 and a hydrogen generator 2 that generates a reformed gas containing hydrogen gas necessary for the fuel cell 1.

  The fuel cell 1 is typically a polymer electrolyte fuel cell, and is configured by laminating a plurality of cells 5 including an anode, a cathode, and a polymer electrolyte membrane disposed between the anode and the cathode. The The fuel cell 1 generates power using a reformed gas containing hydrogen supplied to the anode and an oxidant gas (for example, air) containing oxygen supplied to the cathode. The fuel cell 1 includes an anode channel 3 for supplying reformed gas to the anode, a cathode channel 4 for supplying oxidant gas to the cathode, and heat generated by the electrochemical reaction of hydrogen and oxygen. A cooling path (not shown) for supplying a cooling medium (for example, water) to take away is provided.

  The hydrogen generator 2 includes a reforming reaction unit 19, a shift reaction unit 20, a selective oxidation reaction unit 21, a preheating evaporator 7, a combustor 8, and an air supply unit 15 for combustion. The preheating evaporator 7 is supplied with a reforming fuel (raw material) containing hydrocarbons and reforming water. The preheating evaporator 7 generates steam from the supplied reforming water, mixes the generated steam and reforming fuel, and supplies them to the reforming reaction unit 19. The reforming reaction unit 19 generates reformed gas containing hydrogen by a steam reforming reaction using the reforming fuel and water. Here, the reforming reaction unit 19 and the preheating evaporator 7 are integrated.

  A combustor 8 is disposed on the central axis of the reforming reaction section 19 and the preheating evaporator 7. The combustor 8 includes a burner 9 that forms a flame, an ignition electrode 47, and a combustion state detector 48. An air supply unit 15 and an air flow rate detector (not shown) are connected to the combustor 8. The air supply unit 15 supplies combustion air (combustion air) to the combustor 8. For example, an air pump or a fan can be used as the air supply unit 15. The air flow rate detector measures the flow rate of the combustion air. The combustor 8 may be configured to be incorporated in the hydrogen generator 2 or may be configured as a separate component from the hydrogen generator 2.

  In the combustor 8, reforming in which the concentration of the raw material and carbon monoxide passed as the fuel for combustion until the hydrogen generating device 2 rises to a predetermined temperature is not reduced to a concentration that can be supplied to the fuel cell. Gas or unreacted reformed gas (anode off gas) discharged from the anode of the fuel cell 1 is supplied. The combustor 8 burns these gases to generate heat supplied to the reforming reaction unit 19, for example.

  The hydrogen generator 2 has a plurality of concentric double pipe shapes, and is composed of a combustion cylinder 10, an inner / inner cylinder 11, an inner cylinder 12, and an outer cylinder 13 in this order from the inside.

  In the combustion cylinder 10, the combustion gas is configured to be released from the burner 9. A combustion gas path 14 is formed by an annular space of the combustion cylinder 10 and the inner inner cylinder 11, and is led out of the hydrogen generator 2 from the combustion gas discharge path 25 through the combustion gas path 14.

  In a part of the annular space between the inner cylinder 11 and the inner cylinder 12, a preheating evaporator 7 configured in a spiral shape is provided while circling in the circumferential direction along the outer surface of the inner cylinder. A reforming fuel supply unit 17 that supplies reforming fuel and a reforming water supply unit 18 that supplies reforming water are connected to the outer peripheral surface of the inner cylinder 12 on the upstream side of the preheating evaporator 7. Yes. For example, a booster pump or a gas control valve can be used as the reforming fuel supply unit 17. The reforming fuel supply unit 17 is connected to a reforming fuel supply source (not shown). As the reforming water supply unit 18, for example, a water pump can be used.

In the annular space between the inner cylinder 12 and the outer cylinder 13, a shift reaction part 20 and a selective oxidation reaction part 21 are provided. A reforming fuel supply unit 17 that supplies reforming fuel is provided on the outer peripheral surface of the inner cylinder 12 on the upstream side of the preheating evaporator 7, and a reforming fuel supply unit 17 that supplies reforming fuel is connected thereto. ing.

  Connected to the outer peripheral surface of the outer cylinder 13 is a selective oxidation air supply unit 22 for supplying air necessary for the carbon monoxide selective oxidation reaction of the reformed gas to the selective oxidation reaction unit 21. Further, a reformed gas path 23 for connecting the reformed gas from the hydrogen generator 2 and supplying it to the fuel cell 1 is connected to the outer peripheral surface of the outer cylinder 13.

  On the outer peripheral surface of the outer cylinder 13, a reforming temperature detector 19a, a transformation temperature detector 20a, and a selective oxidation temperature detector 21a are arranged. The reforming temperature detector 19a, the shift temperature detector 20a, and the selective oxidation temperature detector 21a detect the temperatures of the reforming reaction unit 19, the shift reaction unit 20, and the selective oxidation reaction unit 21, respectively. For example, a thermocouple or a thermistor can be used as the reforming temperature detector 19a, the transformation temperature detector 20a, and the selective oxidation temperature detector 21a.

  A reformed gas opening / closing valve 38 is provided in the reformed gas path 23, and the supply of the reformed gas to the anode flow path 3 of the fuel cell 1 can be controlled by opening / closing the reformed gas opening / closing valve 38. The anode flow path 3 and the combustor 8 are connected via an anode off gas path 39. An anode off gas opening / closing valve 40 is disposed in the anode off gas path 39. Further, the reformed gas path 23 upstream of the reformed gas on-off valve 38 and the anode off-gas path 39 downstream of the anode off-gas on-off valve 40 are connected by a reformed gas bypass path 41. A bypass opening / closing valve 42 is provided in the reformed gas bypass path 41, and the flow of gas can be controlled.

  By controlling the opening and closing of these on-off valves, hydrogen that has not been used for the electrochemical reaction in the fuel cell 1 after introducing the reformed gas derived from the reforming reaction unit 19 into the fuel cell 1 and generating electric power. An anode off gas containing can be introduced into the combustor 8. Further, by controlling the opening and closing of these on-off valves, the reforming fuel and reformed gas that have passed through the reforming reaction section 19 can be introduced into the combustor 8 without being introduced into the fuel cell 1.

  The burner 9 of the combustor 8 includes a fuel separator having a plurality of fuel ejection holes and an air ejection member having a plurality of air ejection holes. An ignition electrode 47 and a combustion state detector 48 for detecting the ignition or extinguishing of the flame of the burner 9 are arranged outside the burner 9. As the combustion state detector 48, for example, a flame rod that detects an ionic current in a flame to determine the presence or absence of a flame or a thermocouple that detects a flame temperature and determines the presence or absence of a flame can be used.

  The hydrogen generator 2 is discharged from the fuel cell 1 supplied from the reforming fuel, the reformed gas flowing through the reforming reaction section 19 supplied from the reformed gas bypass path 41, and the anode off-gas path 39. At least one of the anode off-gas and the combustion air supplied from the air supply unit 15 can be burned by the burner 9. The hydrogen generator 2 can heat the reforming reaction section 19 and the preheating evaporator 7 by discharging the high-temperature combustion gas generated by the combustion reaction to the combustion cylinder 10 and circulating the combustion gas path 14.

  The water supply path 26 communicates the reformed water supply unit 18 for supplying water and the preheating evaporator 7. As the reforming water supply unit 18, for example, a water pump can be used.

  A reforming water tank 28 for storing water is connected to the upstream side of the reforming water supply unit 18. Inside the reformed water tank 28, there are a water level detection device 29 for detecting the amount of water stored in the tank, and a water purification unit 30 for removing ions such as chlorine dissolved in the water stored in the tank. Is provided.

The water replenishment path 31 communicates the reformed water tank 28 with a water distillation unit 34 composed of a heating preheating evaporator 32 and a condensing unit 33. Between the water distillation part 34 and the water pipe 35 as a water supply source, the water quantity regulator 36 and the water supply valve 37 are arrange | positioned. The controller 46 controls the fuel cell 1 and the hydrogen generator 2. At least the air supply unit 15, the reforming fuel supply unit 17, the reforming water supply unit 18, the water distillation unit 34, the water amount adjuster 36, The water supply valve 37, the reformed gas on-off valve 38, the anode off-gas on-off valve 40, the bypass on-off valve 42, and the ignition electrode 47 are controlled.

  Next, the operation of the fuel cell system according to the present invention will be described.

  The operation of the fuel cell system is controlled by the controller 46. For example, when the fuel cell system is installed and the initial operation is started, first, the water supply valve 37 is opened and the water pipe 35 is connected to the water amount regulator 36. Water is supplied to the water distillation section 34. At this time, the water amount adjuster 36 adjusts the amount of water so as not to exceed the range of the water distillation capacity of the water distillation unit 34. Furthermore, the operation of the water distillation section 34 is started.

  When the operation of the water distillation section 34 is started, the temperature of the heating preheating evaporator 32 is raised, and the water supplied by the heating preheating evaporator 32 evaporates to become water vapor and flows into the condensation section 33. The water that has flowed into the condensing unit 33 is condensed in the condensing unit 33 to generate condensed water, which is stored in the reformed water tank 28 as water through the water supply path 31.

  When the amount of water stored in the reformed water tank 28 is detected by a water level detection device 29 and reaches a specified amount of water to be circulated and used in the fuel cell system, the water supply valve 37 is closed and the water preheating evaporation of the water distillation section 34 is performed. The operation of the vessel 32 is stopped.

  As a result of this water distillation step, water from which impurities such as silica, potassium, calcium and iron contained in the water supplied from the water pipe 35 are removed is stored in the reformed water tank 28.

  Here, when the fuel cell power generation system is installed and the initial operation is started, the water supply valve 37 is opened, and the amount of water is adjusted so as not to exceed the range of the water distillation capacity of the water distillation unit 34 by the water amount regulator 36. However, the present invention is not limited to this. For example, since it takes time to store water in the reforming water tank 28, the controller 46 can select an operation for supplying water to the reforming water tank 28 without heating and evaporating water during initial operation or maintenance operation. It may be.

  The water stored in the reformed water tank 28 is freed of ions such as chlorine dissolved in the water by the action of the water purification unit 30 to become high purity pure water. Here, as the water purification unit 30, for example, an ion exchange resin can be used.

  When the predetermined water is supplied to the reforming water tank 28, the reforming gas on-off valve 38 and the anode off-gas on-off valve 40 are closed and the bypass on-off valve 42 is opened. When the reformed gas on-off valve 38, the anode off-gas on-off valve 40, and the bypass on-off valve 42 are ready, the reforming fuel supply unit 17 supplies the reforming fuel to the reforming fuel supply unit 17, and the ignition electrode. 47 is activated.

  The supplied reforming fuel flows through the preheating evaporator 7 and the reforming reaction unit 19, passes through the reformed gas path 23, passes through the reformed gas bypass path 41, the bypass on-off valve 42, and the anode offgas path 39. To the combustor 8. The reforming fuel is ejected from the fuel ejection holes of the fuel separator of the combustor 8, mixed with the air ejected from the air ejection holes of the air ejection member, and ignited by the burner 9 to start combustion. The combustor 8 heats at least the reforming reaction section 19 and the preheating evaporator 7 by discharging high-temperature combustion gas into the combustion cylinder 10 and circulating the combustion gas path 14.

  When the combustion state detector 48 detects the ignition of the flame of the combustor 8, the operation of the ignition electrode 47 is stopped, and thereafter, the reforming temperature detector 19a, the shift temperature detector 20a, and the selective oxidation temperature detector 21a are used. Thus, the combustion is continued while detecting the temperature of the reforming catalyst layer, the shift catalyst layer, the selective oxidation catalyst layer or the vicinity thereof.

  Thereafter, the combustion gas causes the temperature detection means 24a, the temperature detection means 24b, and the temperature detection means 24c to have a predetermined temperature equal to or higher than a temperature at which condensation does not occur when a predetermined amount of water is supplied at a temperature higher than the temperature at which water evaporates. When the temperature is heated, the supply of the water in the reformed water tank 28 from the reformed water supply unit 18 via the water supply path 26 is started to the preheating evaporator 7.

  The water supplied to the preheating evaporator 7 is formed in a part of the annular space between the inner inner cylinder 11 and the inner cylinder 12 while circulating in the circumferential direction of the inner inner cylinder 11 along the outer surface of the inner inner cylinder 11. It flows vertically downward along the spiral water path defining portion. At this time, while flowing vertically downward along the water path defining part, the heat from the combustion exhaust gas is absorbed and evaporated to become water vapor, and the reforming fuel is further heated and reformed reaction part 19 To be supplied.

  The reforming reaction unit 19 absorbs heat from the high-temperature combustion gas that has circulated through the combustion gas path 14, and generates a reformed gas (hydrogen-containing gas) by a steam reforming reaction between steam and reforming fuel by the catalyst. Thereafter, the generated reformed gas is further passed through the shift catalyst layer and the selective oxidation catalyst layer, so that the carbon monoxide generated in the reforming reaction is changed to carbon dioxide by the aqueous shift reaction and the selective oxidation reaction. Thereby, the reformed gas containing the high concentration hydrogen which reduced carbon monoxide to about 10 ppm is produced | generated.

  Then, the reformed gas on-off valve 38 and the anode off-gas on-off valve 40 are opened, the bypass on-off valve 42 is closed, and the reformed gas is generated from the reformed gas path 23 into the anode channel 3 of the fuel cell 1. Is generated and reacted with air (cathode air) which is an oxidant gas supplied to the cathode flow path 4 to generate electric power.

  Further, the anode offgas containing hydrogen that has not been used for the electrochemical reaction in the fuel cell 1 is led to the combustor 8 through the anode offgas passage 39 and burned by the burner 9. Thereby, the temperature of the hydrogen generator 2 is maintained at an appropriate value, and the power generation operation of the fuel cell system is continued.

  During operation or when the operation is stopped, the water level detection device 29 detects the amount of water stored in the reforming water tank 28. When the amount of water stored in the reformed water tank 28 becomes equal to or less than a prescribed amount to be circulated and used in the fuel cell system, the water supply valve 37 is opened and water is supplied from the water pipe 35 to the water distillation section 34. . At this time, the water amount adjuster 36 adjusts the amount of water so as not to exceed the range of the water distillation capacity of the water distillation unit 34. Furthermore, the operation of the heating preheating evaporator 32 of the water distillation section 34 is started, condensed water is generated and stored in the reformed water tank 28 as water through the water supply path 31.

  When the amount of water stored in the reformed water tank 28 is detected by the water level detection device 29 and reaches a prescribed amount of water to be circulated and used in the fuel cell system, the water supply valve 37 is closed and the preheat evaporation of the water distillation section 34 is heated. The operation of the vessel 32 is stopped.

As described above, according to the present embodiment, the water to be supplied to the reformed water tank 28 is heated by the water distillation unit 34 and the silica, potassium, calcium, and iron in the water by the above configuration and operation method. After the impurities such as these are removed and condensed, the water is stored in the reformed water tank 28 via the water replenishment path 31, and then this water is supplied to the preheating evaporator 7 of the hydrogen generator 2 by the reformed water supply unit 18. Precipitation of impurities such as silica, potassium, calcium and iron in water can be suppressed from occurring at the water vapor evaporation position of the preheating evaporator 7. Therefore, the preheating evaporator 7 is prevented from being clogged, and the fuel cell system operation can be continued stably.

  Furthermore, since the water supplied to the reforming water tank 28 is heated by the water distillation section 34, dissolved ions such as chlorine ions can be removed and stored in the reforming water tank 28. Therefore, the life of the water purification unit 30 can be extended, and the replacement frequency of the water purification unit 30 can be reduced.

  In addition, since the preheating evaporator 7 can be prevented from being clogged, the preheating evaporator 7 can be reduced in size, and the entire hydrogen generator 2 having a configuration in which the reforming reaction unit 19 and the preheating evaporator 7 are integrated can be made compact. Can do.

(Embodiment 2)
FIG. 2 is a block diagram showing an outline of a fuel cell system according to Embodiment 2 of the present invention.

  2, the same reference numerals as those in FIG. 1 represent the same parts as those in the fuel cell system according to the first embodiment.

  2, the fuel cell system includes an anode off-gas condenser 50 provided on an anode off-gas path 39 connecting the anode flow path 3 of the fuel cell 1 and the combustor 8 in addition to the configuration of the first embodiment. The off-gas condenser 50 and the reformed water tank 28 are connected by an anode condensed water recovery path 51.

  Further, a cathode offgas condenser 52 is provided at the outlet of the cathode flow path 4 of the fuel cell 1, and the cathode offgas condenser 52 and the reformed water tank 28 are connected by a cathode condensed water recovery path 53.

  Further, a combustion exhaust gas condenser 54 is provided at the outlet of the combustion gas discharge path 25, and the combustion exhaust gas condenser 54 and the reformed water tank 28 are connected by a combustion exhaust gas condensed water recovery path 55.

  Next, the operation of the fuel cell system according to the present invention will be described.

  In the anode off-gas condenser 50, the reformed gas derived by bypassing the fuel cell 1 and the water in the anode off-gas after power generation discharged from the outlet of the anode flow path 3 of the fuel cell 1 are condensed and condensed water. Is generated.

  The condensed water generated by the anode off-gas condenser 50 is returned to the reformed water tank 28 via the anode condensed water recovery path 51 and reused as water for the reforming reaction.

  In the cathode offgas condenser 52, the moisture in the cathode offgas after power generation discharged from the outlet of the cathode channel 4 of the fuel cell 1 is condensed to generate condensed water. Further, the cathode off gas may contain moisture supplied to humidify the electrolyte membrane in addition to generated water generated by power generation.

  The condensed water generated by the cathode off-gas condenser 52 is returned to the reformed water tank 28 via the cathode condensed water recovery path 53 and reused as the water for the reforming reaction.

  In the flue gas condenser 54, the reforming fuel, the reformed gas derived by bypassing the fuel cell 1 discharged from the outlet of the combustion gas discharge path 25, and the outlet from the anode passage 3 of the fuel cell 1 are discharged. Water in the combustion exhaust gas obtained by burning at least one of the anode off-gas after power generation by the burner 9 is condensed to generate condensed water.

  The condensed water generated by the combustion exhaust gas condenser 54 is returned to the reformed water tank 28 via the combustion exhaust gas condensed water recovery path 55 and reused as water for reforming reaction.

  With this configuration, it is possible to reduce the amount of water discharged outside the fuel cell system while being circulated in the process of reforming reaction and power generation reaction in the fuel cell system. Therefore, the number of times of water supply can be reduced. Therefore, it is possible to reduce the supply of water containing impurities such as silica, potassium, calcium and iron from the water pipe 35 as a water supply source, and to reduce the energy for heating and distilling the water in the water distillation section 34. can do.

  Moreover, since condensed water with few impurities is used as water, it can suppress more that the precipitation of the impurity in water generate | occur | produces in the location where water evaporates in the preheating evaporator 7. FIG. Therefore, it is possible to provide a fuel cell system that can prevent clogging of preheating evaporator 7 and can continue stable operation.

  The fuel cell system according to the present invention is useful, for example, as a stationary fuel cell system such as a household fuel cell cogeneration system and an emergency power source.

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Hydrogen generator 3 Anode flow path 4 Cathode flow path 5 Cell 7 Preheating evaporator 8 Combustor 9 Burner 10 Combustion cylinder 11 Inner cylinder 12 Inner cylinder 13 Outer cylinder 14 Combustion gas path 15 Air supply part 17 Reformation Fuel supply unit 18 Reformed water supply unit 19 Reforming reaction unit 19a Reforming temperature detector 20 Transformation reaction unit 20a Transformation temperature detector 21 Selective oxidation reaction unit 21a Selective oxidation temperature detector 22 Selective oxidation air supply unit 23 Reformation Gas path 25 Combustion gas discharge path 26 Water supply path 28 Reformed water tank 29 Water level detection device 30 Water purification section 31 Water replenishment path 32 Heating preheat evaporator 33 Condensing section 34 Water distillation section 35 Water pipe 36 Water regulator 37 Water supply valve 38 Reformed Gas On / Off Valve 39 Anode Off Gas Path 40 Anode Off Gas On / Off Valve 41 Reformed Gas Bypass Path 42 Bypass On / Off Valve 46 controller 47 ignition electrode 48 combustion state detector 50 anode off-gas condenser 51 anode condensed water recovery path 52 cathode off-gas condenser 53 cathode condensed water recovery path 54 combustion exhaust gas condenser 55 combustion exhaust gas condensed water recovery path

Claims (4)

A combustor for generating combustion gas, steam from water using the heat of the combustion gas, a preheating evaporator for mixing the generated steam and the supplied raw material, and a downstream side of the preheating evaporator A hydrogen generating device that is disposed and heated using the heat of the combustion gas to generate a hydrogen-containing gas from a raw material and steam by a steam reforming reaction;
A fuel cell that generates electricity by reacting a hydrogen-containing gas and oxygen generated by the hydrogen generator;
A reforming water tank for storing water to be supplied to the preheating evaporator;
A water supply path communicating the reformed water tank and the preheat evaporator;
A reforming water supply unit provided on the water supply path for supplying water to the preheating evaporator;
A water distillation section for heating and distilling water supplied to the reformed water tank;
A water replenishment path communicating the water distillation section and the reformed water tank;
A fuel cell system comprising: Of the combustion exhaust gas discharged from the combustor, the anode off-gas after power generation discharged from the fuel electrode side outlet of the fuel cell, and the cathode off-gas after power generation discharged from the air electrode side of the fuel cell A condenser for condensing moisture in at least one of the gases;
A condensed water recovery path for supplying condensed water recovered from the condenser to the reformed water tank;
The fuel cell system according to claim 1, further comprising:   The water purification part provided in the said reforming water tank or the water supply path which connects the said reforming water tank and the said preheating evaporator of a hydrogen production | generation apparatus was further provided. Fuel cell system. The preheating evaporator includes an inner cylinder and an outer cylinder having different diameters arranged concentrically with the combustor, a combustion gas path formed so that combustion gas flows along an inner surface of the inner cylinder, and the inner cylinder A water path defining portion that circulates the water along the outer surface of the inner cylinder in a part of the annular space between the cylinder and the outer cylinder;
The fuel cell system according to claim 1, wherein the reforming reaction unit is configured to fill the annular space downstream of the preheating evaporator with a reforming catalyst.

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