JP2010238446A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system which is advantageous in carrying out water vaporization in an evaporator, for heating the evaporator by receiving exhaust heat of exhaust gas generated in the power generation operation and receiving reaction heat of a purifying catalyst of a fuel cell. <P>SOLUTION: The fuel cell system has an evaporator 5, which evaporates reforming water and generates steam; a reformer 4, which reforms fuel raw material by steam generated in the evaporator 5 and produces an anode gas; and an exhaust gas passage 6, which discharges the exhaust gas generated accompanied with power generation operation of the fuel cell. An evaporation chamber 50 of the evaporator 5 is installed, capable of heat exchanging with the exhaust gas flowing in the passage portion 64, making a part of the exhaust gas passage 6 and generates steam by being heated by the exhaust gas. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel cell system having an evaporation section that vaporizes reformed water to generate water vapor.

  Patent Documents 1 and 2 disclose a fuel cell system having an evaporation section and a reforming section that are heated by a combustion flame in which an anode off-gas after power generation reaction discharged from a fuel cell is combusted. In this case, since the evaporation section is heated by a combustion flame in which the anode off gas after the power generation reaction discharged from the fuel cell is combusted, the evaporation section is disposed directly above the fuel cell. It becomes a structure. In this case, since the evaporating part performs an endothermic action by the heat of vaporization, there is a possibility that the temperature rise of the fuel cell may be limited.

  Patent Document 3 includes a reformer that generates a hydrogen-rich anode gas, a water heating means, and a fuel cell, and recovers water and heat from exhaust gas discharged from the fuel cell. A fuel cell system is disclosed that includes a tank, a recovered water tank that stores the water recovered by the recovery device, and a pump that supplies water from the recovered water tank to the water heating means. According to Patent Document 3, a passage through which high-temperature exhaust gas generated by a power generation reaction of a fuel cell is directed to an evaporation unit or a desulfurizer and the evaporation unit or the desulfurizer is heated is illustrated.

  In Patent Document 4, the water vapor generator includes a heat exchanger that uses exhaust gas from the fuel cell as a heat source, and an unburned gas in the exhaust gas at the time of startup is provided in the exhaust gas flow path of the heat exchanger. There is disclosed a fuel cell system provided with a combustion catalyst for burning the fuel.

JP 2007-12313 A JP 2007-207446 A JP 2006-309982 A JP 2007-80761 A

  There is a demand for development of a fuel cell system that is a step further than the above-described conventional fuel cell system.

  The present invention has been made in view of the above circumstances, and receives the exhaust heat of exhaust gas generated in the power generation operation of the fuel cell and the reaction heat of the purification catalyst, heats the evaporation section, and steams the evaporation section. It is an object of the present invention to provide a fuel cell system advantageous for execution.

  The fuel cell system according to the present invention includes an evaporation section that vaporizes reformed water to generate steam, a reforming section that reforms a fuel material with the steam generated in the evaporation section to generate anode gas, and a modification. A solid oxide fuel cell that generates electricity using the anode gas and cathode gas generated in the mass part, an exhaust gas passage that discharges exhaust gas generated during power generation operation of the fuel cell, and an exhaust gas passage. A purification unit having a purification catalyst for purifying the exhaust gas by reducing an environmental influence component contained in the exhaust gas flowing through the exhaust gas passage, and the evaporation unit is configured to exhaust heat of the exhaust gas flowing through the exhaust gas passage. And a vapor generation chamber for steam generation provided to receive the reaction heat of the purification catalyst.

  The evaporating section has a vaporizing chamber that vaporizes the reformed water to generate water vapor. The reforming unit steam-reforms the fuel material with the steam generated in the evaporation unit to generate anode gas. The anode gas is supplied to the fuel cell and used for power generation operation. The fuel cell is in the form of a solid oxide and generates electricity with the anode gas and the cathode gas generated in the reforming section. The exhaust gas passage discharges the exhaust gas generated with the power generation operation of the fuel cell to the outside.

  The vaporizing chamber of the evaporation unit is provided so as to receive the exhaust heat of the exhaust gas flowing through the exhaust gas passage and the reaction heat of the purification unit. For this reason, the vaporization chamber of the evaporation section receives both the exhaust heat of the exhaust gas flowing through the exhaust gas passage and the reaction heat of the purification section, so that the temperature rising property of the vaporization chamber is secured, and consequently the water vapor generation property of the vaporization chamber is ensured. Secured. The steam generated in the vaporization chamber is supplied to the reforming section, used for steam reforming in the reforming section, and the gaseous or liquid fuel material is used as the anode gas.

  According to the present invention, the vaporizing chamber of the evaporation unit is provided so as to receive the exhaust heat of the exhaust gas flowing through the exhaust gas passage and the reaction heat of the purification unit. Therefore, the exhaust gas and the temperature of the purification unit can be lowered. Therefore, even when the purification unit generates heat due to the purification reaction, overheating in the purification unit is suppressed, deterioration of the purification catalyst due to overheating is suppressed, and durability of the purification catalyst can be improved.

  Advantageous Effects of Invention According to the present invention, a fuel cell system that is advantageous for receiving exhaust heat of exhaust gas generated during power generation operation of a fuel cell and reaction heat of a purification catalyst to heat the evaporation section and to perform steaming in the evaporation section. Can provide.

1 is a diagram schematically showing a fuel cell system according to Embodiment 1. FIG. 1 is a perspective view schematically showing a vicinity of a stack of a fuel cell system according to Embodiment 1. FIG. FIG. 6 is a diagram schematically showing a fuel cell system according to Embodiment 2. FIG. 10 is a diagram schematically showing a fuel cell system according to Embodiment 3. FIG. 10 is a diagram schematically showing a fuel cell system according to a fourth embodiment. FIG. 10 is a cross-sectional view schematically showing the vicinity of a purification unit of a fuel cell system according to Embodiment 5. FIG. 10 is a cross-sectional view schematically showing the vicinity of a purification unit of a fuel cell system according to Embodiment 6. FIG. 10 is a partial cross-sectional view schematically showing a portion obtained by cutting the vicinity of the exhaust gas passage of the fuel cell system along the horizontal direction according to the seventh embodiment.

  According to a preferred embodiment, it is preferable that a heat insulating layer is provided between the fuel cell and the evaporation section. The heat insulation layer is based on a heat insulation material that suppresses the influence of the heat of vaporization of the evaporation section on the fuel cell by enhancing the heat insulation between the fuel cell and the evaporation section. According to a preferred embodiment, the evaporation section has a water storage section that communicates with the vaporization chamber and stores liquid reforming water. According to a preferred embodiment, the passage portion of the exhaust gas passage has a flow passage restriction portion that is located downstream of the purification portion and has a flow passage cross-sectional area that is smaller than a flow passage cross-sectional area upstream of the purification portion. The water storage cross-sectional area is increased by the flow restrictor. In this case, the amount of water stored in the water storage unit is secured.

  A hot water storage system is preferably provided. The hot water storage system is a circulation passage by exchanging heat between a hot water storage tank, a circulation passage for circulating water in the hot water storage tank, a water conveyance source for circulating water in the circulation passage, and water in the circulation passage and exhaust gas in the exhaust gas passage. It is preferable to have a hot water storage heat exchanger for heating the water. In this case, it is preferable that the evaporator is disposed between the hot water storage heat exchanger and the fuel cell. That is, it is preferable that the evaporator is disposed upstream of the hot water storage heat exchanger in the flow direction of the exhaust gas flowing through the exhaust gas passage. Here, assuming that the heat exchange amount for exchanging heat between the exhaust gas and the evaporation unit per unit time is Q1, and the heat exchange amount for exchanging heat between the exhaust gas and the hot water storage heat exchanger is Q2, the relationship of Q1 <Q2 is satisfied. It is said that. In particular, the relationship is Q1 << Q2. For this reason, the heat exchange amount in the hot water storage heat exchanger is not greatly affected. Therefore, it is possible to contribute to maintaining the temperature of the water in the hot water storage tank at a high temperature while performing steaming in the evaporation section using the heat of the exhaust gas.

  According to a preferred embodiment, the passage portion of the exhaust gas passage has a passage forming member that can be attached to and detached from the exhaust gas passage. Preferably, the passage forming member includes a first cylinder having a passage through which exhaust gas passes, a gas permeable purification unit disposed in the passage and having a purification catalyst, and a vaporization disposed adjacent to the first cylinder. And an evaporation section that forms a chamber. The purification unit and the evaporation unit are integrated and can be attached to and detached from the exhaust gas passage, which is suitable for maintenance. The term “adjacent installation” means that it is installed next to each other so that heat can be transferred, and includes a configuration in which it is installed directly next to it, and a configuration in which it is installed next to another member such as a wall. Preferably, the vaporization chamber and the purification unit are adjacent to each other via a metal wall. Heat transfer between the vaporizing chamber and the purification unit is improved. Further, a heat insulating layer may be disposed between the vaporizing chamber and the purification unit. Mild cooling of the purification section can be achieved. Assuming that the dimension in the flow direction of the exhaust gas is L and the dimension in the direction perpendicular to the flow direction of the exhaust gas is D, the value of L / D is exemplified as 1 or less, 0.7 or less. 4 or more are exemplified.

(Embodiment 1)
FIG. 1 is a conceptual diagram of the first embodiment. This embodiment is applied to a solid oxide fuel cell system. First, the fuel cell device will be described. The fuel cell device 1 causes the combustion section 27 to combust the shell 3 having the power generation chamber 30, the stack 2 formed of the fuel cells 20 disposed in the power generation chamber 30, and the anode off-gas discharged from the stack 2. Heat exchange with the reforming section 4 heated by the combustion flame 28, the evaporation section 5 for supplying water vapor to the reforming section 4, the exhaust gas passage 6 for discharging the exhaust gas of the combustion flame 28, and the exhaust gas passage 6 The cathode gas passage 7 adjacent to the exhaust gas passage 6, the first heat insulating layer 37 formed of a heat insulating material provided on the lateral portion of the stack 2, and the heat insulating material provided on the lower portion of the stack 2. And a second heat insulating layer 38 formed of The power generation chamber 30 accommodates the stack 2, the first heat insulation layer 37, the second heat insulation layer 38, and the reforming unit 4, but does not contain the following evaporation unit 5. The inside of the power generation chamber 30 is maintained at a high temperature by the first heat insulating layer 37 and the second heat insulating layer 38.

As shown in FIG. 2, the stack 2 accommodated in the power generation chamber 30 is formed by arranging a plurality of fuel cells 20 in parallel through a passage 30r through which the cathode gas flows. Adjacent fuel cells 20 are electrically connected by a conductive member (not shown). The fuel cell 20 is supplied with an anode 21 that functions as a fuel electrode, a cathode 22 that functions as an oxidant electrode, an electrolyte 23 based on a solid oxide sandwiched between the anode 21 and the cathode 22, and an anode gas. A porous conductive portion 24 having a passage 24r, and a connector 25. The cathode 22 faces the passage 30r through which the cathode gas flows. The solid oxide constituting the electrolyte 23 has a property of conducting oxygen ions (O ²⁻ ), and examples thereof include zirconia and lanthanum gallates such as YSZ. Examples of the anode 21 include nickel-ceria cermets and conductive ceramics. Examples of the cathode 22 include samarium cobaltite and lanthanum manganite. The material is not limited to the above. The connector 25 can be formed of dense conductive ceramics.

  An anode gas manifold 13 is formed in the lower part of the stack 2. The reformer 4 and the anode gas manifold 13 are connected by an anode gas passage 14. The anode gas generated in the reforming unit 4 flows through the anode gas passage 14 to the anode gas manifold 13, further flows into the passage 24 r of the porous conductive unit 24, and is supplied to the anode 21.

  As shown in FIG. 1, the exhaust gas passage 6 discharges exhaust gas (exhaust gas of the combustion flame 28) generated during power generation operation of the stack 2 from the power generation chamber 30 to the outside, and is connected to the power generation chamber 30. A merge passage 63 is formed by joining the first exhaust gas passage 61 and the second exhaust gas passage 62, and a passage portion 64 is connected to the merge passage 63. A distal end portion 65 that is a discharge port of the passage portion 64 communicates with the outside air.

  In the middle of the passage portion 64, the evaporating section 5 is provided next to the passage section 64. In the drawing, the passage portion 64 and the evaporator 5 are illustrated as being coaxial with each other, but the present invention is not limited to this. The evaporation unit 5 is disposed below the stack 2 via the second heat insulating layer 38. The evaporating unit 5 communicates with the vaporizing chamber 50 adjacent to the passage portion 64, the surrounding wall 51 forming the vaporizing chamber 50, the vaporizing chamber 50 below the vaporizing chamber 50, and liquid reforming water 56. And a water storage section 52 for storing. The water reservoir 52 constitutes the bottom of the vaporizing chamber 50. The vaporizing chamber 50 is preferably arranged in a cylindrical shape coaxially with the passage portion 64. The evaporation part 5 can be covered with a third heat insulating layer 39 for heat insulation. However, it is not limited to this.

  As shown in FIG. 1, the reforming water system 40 that supplies reforming water supplies reforming water that is consumed as water vapor in steam reforming in the reforming unit 4 to the reforming unit 4 via the evaporation unit 5. Is. The reforming water system 40 is in communication with the water purifier 41 having a purification material 41a such as an ion exchange resin that can purify water such as condensed water generated in the system, and the water purifier 41. A reformed water tank 42 that stores the generated water as the reformed water 42w, a reformed water supply passage 43 that connects the reformed water tank 42 and the evaporator 5, and a reformed water pump 44 (reformed water transport source). And a water supply valve 45.

  If the reforming water pump 44 is operated with the water supply valve 45 opened, the water in the reforming water tank 42 is supplied from the water supply port 53 through the reforming water supply passage 43 to the water supply port of the vaporization chamber 50 of the evaporation unit 5. 53. The water supply port 53 and the discharge port 55 are preferably positioned above the water surface 56w of the reformed water 56 of the water storage section 52 of the evaporation section 5. However, it is not limited to this. As can be understood from FIG. 1, the water storage section 52 is disposed in the exhaust gas passage 6 so as to face a portion downstream of the purification section 66.

  The reforming unit 4 preferably includes a container 4a, a carrier formed of ceramics accommodated in the container 4a, and a reforming catalyst carried on the carrier. The carrier may be monolithic or pellet-shaped. The reforming catalyst may be a noble metal catalyst or a base metal catalyst. Examples of the noble metal catalyst include platinum, palladium, rhodium, ruthenium and the like. Examples of the ceramic for the carrier include alumina, magnesia, and silica.

  The passage portion 64 of the exhaust gas passage 6 has a purification unit 66 having a purification catalyst. The purifying unit 66 purifies the exhaust gas by combusting environmental impact components (generally carbon monoxide or the like) contained in the exhaust gas generated during the power generation operation. Since the purification reaction is an oxidation reaction, it generates heat. The purification unit 66 preferably has a carrier made of ceramics and a purification catalyst for purification carried on the carrier. The carrier may be monolithic or pellet-shaped. The purification catalyst for purification may be a noble metal catalyst or a base metal catalyst. Examples of the noble metal catalyst include platinum, palladium, rhodium, ruthenium and the like. Examples of the ceramic for the carrier include alumina, magnesia, and silica. Examples of the activation temperature range of the purification catalyst for purification include a range of 100 to 400 ° C and a range of 150 to 350 ° C. However, it is not limited to this.

  As shown in FIG. 1, the evaporation unit 5 and the purification unit 66 are arranged below the stack 2 in the gravitational direction. The vaporization chamber 50 of the evaporation unit 5 is partitioned by a metal cylindrical outer wall 59. The vaporizing chamber 50 is opposed to the passage portion 64 and the purification portion 66 of the exhaust gas passage 6 via a metal cylindrical surrounding wall portion 51, and the vaporization chamber 50 can transfer heat to the purification portion 66. It is next to. For this reason, the heat of the exhaust gas flowing through the exhaust gas passage portion 64 is easily transmitted to the vaporization chamber 50 of the evaporation unit 5 and thus to the water storage unit 52. In this case, the inside of the vaporizing chamber 50 is heated by the exhaust heat of the exhaust gas flowing through the passage portion 64 of the exhaust gas passage 6. Further, when the exhaust gas is purified by the purification reaction of the purification unit 66, reaction heat based on the purification reaction (oxidation reaction, exothermic reaction) is also transmitted to the inside of the vaporizing chamber 50. As a result, the reformed water stored in the water storage section 52 can be effectively heated, and water vapor can be generated satisfactorily in the vaporization chamber 50.

  In order to make it easier for the heat of the exhaust gas to be transmitted to the evaporation section 5, a heat transfer promotion member such as a heat transfer fin or a heat transfer promotion ball may be provided. For example, heat transfer fins are provided in the inside of the evaporation section 5 (vaporization chamber 50, water storage section 52) on the outer periphery of the passage portion 64 of the exhaust gas passage 6, or inside the evaporation section 5 (vaporization chamber 50, water storage section 52). A heat transfer promoting ball such as an alumina ball may be accommodated in the container.

  When the purification unit 66 oxidizes and reduces the environmental impact components contained in the exhaust gas, the purification unit 66 generates heat. At this time, the purification unit 66 and the evaporation unit 5 exchange heat with each other. Therefore, heat is transferred from the purification unit 66 to the vaporization chamber 50 of the evaporation unit 5, and overheating of the purification unit 66 is suppressed. As a result, deterioration of the purification catalyst due to overheating is suppressed, and durability of the purification catalyst can be improved. In addition, since the evaporation part 5 is coaxially arrange | positioned at the outer peripheral side of the purification | cleaning part 66, the size of the radial direction (arrow DA direction) of the vaporization chamber 50 of the evaporation part 5 is ensured, and the volume of the vaporization chamber 50 is ensured. Is done. Furthermore, the entire circumference of the evaporation section 5 becomes a heat transfer path, and a heat transfer area from the passage portion 64 and the purification section 66 to the vaporization chamber 50 is easily secured, which can contribute to heating of the vaporization chamber 50.

  As shown in FIG. 1, the passage portion 64 of the exhaust gas passage 6 has a flow restrictor 67. The flow path narrowing part 67 is located downstream of the purification part 66 and is surrounded by the vaporization chamber 50 of the evaporation part 5. The channel cross-sectional area S1 of the channel restricting portion 67 is smaller than the channel cross-sectional area S2 upstream of the purification unit 66. For this reason, the cross-sectional area of the water storage part 52 in the radial direction (arrow DA direction) is larger than the cross-sectional area of the vaporization chamber 50 in the radial direction (arrow DA direction). These cross-sectional areas can also be said to be the cross-sectional areas perpendicular to the flow direction (A3 direction) of the exhaust gas flowing through the passage portion 64 of the exhaust gas passage 6. That is, the cross-sectional area D1 on one side of the water storage section 52 is larger than the cross-sectional area D2 on one side of the vaporization chamber 50. Therefore, compared with the case where the flow path restricting portion 67 is not formed, the inner diameter of the cylindrical water storage portion 52 is reduced, and the total cross-sectional area is increased and increased. For this reason, the water storage amount in the water storage part 52 is ensured. Furthermore, since the cross-sectional area defined by the outer diameter of the purifying unit 66 is secured to the same extent as the flow path cross-sectional area S2, the purifying effect of the purifying unit 66 purifying the exhaust gas can be enhanced. However, the flow restrictor 67 may be provided as necessary, and the flow restrictor 67 may be eliminated and the inner diameter of the passage portion 64 may be the same in the length direction thereof.

  As shown in FIG. 1, since the flow restrictor 67 is provided downstream of the purification unit 66, the cross-sectional area of the purification unit 66 is ensured to be approximately the same as the flow cross-sectional area S2, and is secured to be large. . Therefore, it is possible to suppress the flow rate of the exhaust gas passing through the purification unit 66 from being excessively increased. As a result, the contact reaction time between the purification catalyst and the exhaust gas in the purification unit 66 is secured, the time required for the purification reaction in the purification unit 66 is secured, and the purification effect is enhanced.

  Further, in consideration of reducing the variation in purification reaction in the radial direction (arrow DA direction) of the purification unit 66, in the radial direction (arrow DA direction) of the purification unit 66, the exhaust gas is discharged between the central region and the outer edge region. It is preferable to reduce variations in flow rate. Here, a flow passage restricting portion 67 that causes pressure loss is provided downstream of the purifying portion 66. For this reason, in the radial direction (arrow DA direction) of the purification unit 66, it is possible to suppress an excessive increase in the variation in the exhaust gas flow velocity between the central region and the outer edge region. In this case, in the purification unit 66, variation in purification reaction is reduced between the central region and the outer edge region in the radial direction (arrow DA direction), and purification unevenness in the radial direction is reduced.

  As shown in FIG. 1, the exhaust gas passage 6 is branched into a first exhaust gas passage 61 and a second exhaust gas passage 62, and the cathode gas flowing through the cathode gas supply 96 is preheated by exchanging heat at a plurality of locations. it can. The purifying unit 66 communicates with the joining passage 63 obtained by joining the first exhaust gas passage 61 and the second exhaust gas passage 62 that have been branched in this way. For this reason, the purification | cleaning part 66 is a common purification | cleaning part which is common to both the 1st exhaust gas passage 61 and the 2nd exhaust gas passage 62 which are branched, and can reduce the number of the purification | cleaning parts 66. FIG.

  As shown in FIG. 1, a hot water storage system 8 is provided. The hot water storage system 8 includes a hot water storage tank 80, a circulation passage 81 that circulates water in the hot water storage tank 80, a hot water storage pump 82 that functions as a water conveyance source for circulating water in the circulation passage 81, and water and exhaust gas in the circulation passage 81. It has a hot water storage heat exchanger 83 having a heat exchange passage 81a that heats water by exchanging heat with the exhaust gas in the passage 6. In this case, the evaporator 5 is disposed between the hot water storage heat exchanger 83 and the stack 2. That is, the evaporator 5 is disposed upstream of the hot water storage heat exchanger 83 in the flow direction of the exhaust gas flowing in the passage portion 64 of the exhaust gas passage 6 (in the directions of arrows A2, A3, and A4).

  Here, per unit time (for example, 1 minute), the flow rate of the reforming water supplied to the evaporation unit 5 when the pump 44 is operated is V1, and the flow rate of the hot water supplied to the hot water storage heat exchanger 83 is V2. Then, the relationship of V1 <V2 is established. In particular, the relationship is V1 << V2. In addition, the heat exchange amount exchanged in the evaporation unit 5 by heat transfer from the exhaust gas and the purification unit 66 per unit time (for example, 1 minute) is defined as Q1, and the heat is exchanged in the heat exchange passage 81a of the hot water storage heat exchanger 83. When the exchanged heat exchange amount is Q2, the relationship is Q1 <Q2. In particular, the relationship is Q1 << Q2. For this reason, even if the reformed water stored in the water storage section 52 of the evaporation section 5 is vaporized by heating with the exhaust gas in the passage portion 64 and the heat of the purification section 66, the temperature drop of the exhaust gas is not excessive. Absent. Therefore, the heat exchange amount in the heat exchange passage 81a of the hot water storage heat exchanger 83 is not greatly affected. Therefore, it is possible to contribute to maintaining the hot water temperature of the hot water storage tank 80 as high as possible while heating the evaporation unit 5 with the heat of the exhaust gas and the purification unit 66 to vaporize the reformed water in the evaporation unit 5.

  As shown in FIG. 1, the fuel material supply system 9 includes a fuel material supply passage 90 connected to a fuel source 93 for supplying a hydrocarbon-based gaseous or liquid fuel material to the reforming unit 4, and an inlet valve 91. And a fuel material pump (fuel material conveyance source) 92. The cathode gas supply yarn 95 includes a cathode gas supply passage 96 that supplies a cathode gas that is air to the cathode of the stack 2, and a cathode gas pump (cathode gas conveyance source) 97. The cathode gas passage 7 connected to the cathode gas supply passage 96 includes a first passage 71 that exchanges heat with the first exhaust gas passage 61 and the second exhaust gas passage 62, a second passage 72, and a first passage sandwiched between the stacks 2. 3 passages 73. The lead-out port 74 on the distal end side of the third passage 73 faces the power generation chamber 30, and thus faces the gap 30 r for passing the cathode gas formed between the cells 20 of the stack 2 accommodated in the power generation chamber 30. .

When the stack 2 is started, the fuel material pump 92 is driven with the inlet valve 91 opened, and gaseous or liquid fuel material is supplied to the reforming unit 4 via the fuel material supply passage 90. The fuel material supplied to the reforming unit 4 is supplied to the anode 21 via the anode gas passage 14 and the anode gas manifold 13. On the other hand, the cathode gas pump 97 is driven, and cathode gas (air) is supplied to the cathode 22 through the cathode gas supply passage 96 and the cathode gas passage 7. Immediately after startup, since the temperature of the fuel cell 20 is low, no power generation reaction takes place, and the fuel material and cathode gas are supplied as they are to the combustion section 27 at the top of the stack 2, and the fuel material burns with the cathode gas. A combustion flame 28 is generated and the reforming unit 4 is heated. In this case, air is supplied to the reforming unit 4 together with the fuel material from an unillustrated air passage. As a result, the fuel raw material undergoes a partial oxidation reaction (for example, 2CH ₄ + O ₂ → 4H ₂ + CO) with oxygen contained in the air to generate heat and generate a hydrogen-containing gas (combustible gas). The hydrogen-containing gas is combusted by air in the combustion section 27 at the top of the stack 2 to generate a combustion flame 28 and heat the reforming section 4. During such startup, the exhaust gas of the combustion flame 28 flows through the exhaust gas passage 6 in the directions of arrows A1, A2, A3, and A4, and is discharged from the front end portion 65 (exhaust port) of the exhaust gas passage 6 to the outside of the system. . In this case, the purification unit 66 and the evaporation unit 5 are heat-exchanged and preheated by the high-temperature exhaust gas. At the start of startup, it is preferable that no reforming water exists in the water storage section 52 of the evaporation section 5. This is to prevent the endothermic effect due to the heat of vaporization from affecting the temperature rise of the purification unit 66. In this case, it is advantageous to quickly start the purification catalyst of the purification unit 66 by raising the temperature to the activation temperature region. When the power generation operation of the fuel cell device 1 is stopped, there is residual heat because the power generation temperature of the stack 2 is high. In general, since the remaining heat is transmitted to the evaporation unit 5 over a long period of time while the operation is stopped, the reformed water remaining in the water storage unit 52 is evaporated and becomes empty.

The reforming water pump 44 is activated, reforming water is supplied to the water storage unit 52 of the evaporation unit 5, steam is generated in the vaporizing chamber 50, and the steam is supplied to the reforming unit 4 through the steam passage 57. Further, as described above, the fuel material pump 92 is driven, and the fuel material is supplied to the reforming unit 4 via the fuel material supply passage 90. At this time, the air supplied to the reforming unit 4 is blocked. The reforming unit 4 performs steam reforming of the fuel material with the steam supplied from the evaporation unit 5 to generate a hydrogen-rich anode gas. When the fuel raw material is methane-based, it is considered that the generation of the anode gas in the steam reforming is based on the following equation (1). This reaction is an endothermic reaction. In the solid oxide stack 21 may CO becomes a fuel into H ₂ others.

(1) ... CH ₄ + 2H ₂ O → 4H ₂ + CO ₂
CH ₄ + H ₂ O → 3H ₂ + CO
The generated anode gas is supplied to the passage 24r (see FIG. 2) of the porous conductive portion 24 on the anode 21 side of the stack 2 via the anode gas passage 14 and the anode gas manifold 13 to generate power generation reaction of the anode 21. used. Since the cathode gas pump 97 is driven, outside air is supplied as cathode gas to the power generation chamber 30 through the dust filter 98 and the cathode gas supply passage 96. As a result, the stack 2 generates power.

In the power generation reaction, it is considered that the reaction (2) basically occurs at the anode 21 supplied with the hydrogen-containing gas. It is considered that the reaction (3) basically occurs at the cathode 22 to which oxygen is supplied. Oxygen ions (O ²⁻ ) generated at the cathode 22 conduct through the electrolyte 23 from the cathode 22 toward the anode 21.

(2) ... H ₂ + O ²⁻ → H ₂ O + 2e ⁻
When CO is contained, CO + O ²⁻ → CO ₂ + 2e ⁻
(3)... 1 / 2O ₂ + 2e ⁻ → O ²⁻
The anode off-gas after the power generation reaction has a combustible component and is discharged to the combustion part 27 above the stack 2 to form a combustion flame 28 in the combustion part 27. The exhaust gas of the combustion flame 28 flows from the power generation chamber 30 to the first exhaust gas passage 61 and the second exhaust gas passage 62 and flows in the directions of arrows A1, A2, A3, and A4. It flows to the passage portion 64. At this time, in the purifying unit 66, the environmental influence component contained in the exhaust gas is removed by the purification reaction (oxidation reaction, exothermic reaction), and the exhaust gas is purified. Examples of the environmental impact component include unburned components, and examples thereof include oxygen monoxide.

  The purified exhaust gas flows into the hot water storage heat exchanger 83, exchanges heat with the water in the circulation passage 81, and then is discharged from the front end portion 65 of the exhaust gas passage 6 to the outside air. Since the exhaust gas is cooled when flowing through the hot water storage heat exchanger 83, the moisture contained in the exhaust gas is condensed as condensed water. The condensed water is supplied to the water purifier 41 from the condensed water passage 84 led out from the hot water storage heat exchanger 83 and purified by the water purifier 41. The purified water is stored in the reforming water tank 42 as reforming water.

  As described above, the anode off gas is discharged from the upper part of the stack 2 to the combustion unit 27 to form the combustion flame 28, and the reforming unit 4 is heated. Therefore, the flow rate of the anode gas (fuel material) is set to a flow rate obtained by adding the flow rate used in the power generation reaction at the anode 21 of the stack 2 and the flow rate at which the anode off gas forms the combustion flame 28 in the combustion unit 27. ing. As the flow rate of the cathode gas supplied to the power generation chamber 30, the flow rate used in the power generation reaction at the cathode of the stack 2, the flow rate for forming the combustion flame 28 as combustion air in the combustion unit 30, and the surplus flow rate are added. The set flow rate is set. In addition, according to the system in which the solid oxide stack 2 is mounted, the operating temperature of the stack 2 in rated operation depends on factors such as the material of the electrolyte 23, but is within the range of 400 to 1100 ° C, 500 to 800 ° C. Is within the range.

  According to the present embodiment, during the power generation operation, the temperature of the exhaust gas flowing through the passage portion 64 of the exhaust gas passage 6 (upstream of the purification unit 66) is high, and the material, type, power generation conditions, etc. of the stack 2 are also considered. However, for example, it is in the range of 200 to 900 ° C. and in the range of 250 to 800 ° C. Such a high-temperature exhaust gas efficiently heats the evaporation unit 5. Then, the reformed water 56 in the water storage section 52 is heated, and steaming is promoted in the vaporizing chamber 50. As a result, the water vapor generated in the vaporization chamber 50 of the evaporation unit 5 is discharged to the water vapor passage 57 via the discharge port 55 and supplied to the inlet port 4 i of the reforming unit 4.

  As described above, according to the present embodiment, during the power generation operation of the system, the evaporation unit 5 exhausts exhaust gas flowing through the passage portion 64 that forms part of the exhaust gas passage 6 and reaction heat of the purification unit 66. Is provided so that it can receive heat directly or indirectly. That is, the evaporation unit 5 is provided so as to be able to exchange heat directly or indirectly with the exhaust heat of the exhaust gas flowing through the passage portion 64 that forms part of the exhaust gas passage 6 and the reaction heat of the purification unit 66. Thus, the evaporation part 5 has the vaporization chamber 50 which is heated and produces | generates water vapor | steam. The steam is supplied to the reforming unit 4 through the steam passage 57 and is used for steam reforming in the reforming unit 4. Thus, the gaseous or liquid fuel material is used as the anode gas.

  When water is vaporized in the evaporating unit 5, the influence of the heat of vaporization of water is large, so that the temperature of the stack 2 may be lowered depending on the power generation conditions, which affects the power generation reaction of the fuel cells 20 of the stack 2. There is a fear. However, according to the present embodiment, the evaporation unit 5 is heated by the exhaust heat of the exhaust gas generated in the power generation operation of the stack 2 and the reaction heat of the purification unit 66. For this reason, the influence which the heat absorption by the vaporization heat in the evaporation part 5 has on the stack 2 is suppressed. Further, it is not preferable to discharge the excessively high temperature exhaust gas as it is outside the system. In this respect, according to the present embodiment, the heat of the exhaust gas is taken away as the heat of vaporization in the evaporation unit 5, so that it can be expected that the temperature of the exhaust gas discharged from the front end portion 65 of the exhaust gas passage 6 is lowered. Therefore, the exhaust gas is cooled so that the moisture contained in the exhaust gas is recovered as condensed water. In addition, the exhaust gas released to the outside air is rapidly cooled to white smoke in winter and cold districts. Is suppressed.

  According to this embodiment, as shown in FIG. 1, the second heat insulating layer 38 is interposed between the stack 2 and the evaporation unit 5. For this reason, not only the stack 2 and the evaporation unit 5 are separated from each other, but also the heat absorption due to the vaporization heat in the evaporation unit 5 is suppressed from affecting the power generation temperature of the stack 2. Therefore, in the power generation operation, it is possible to contribute to maintaining the temperature of the stack 2 stably and at a high level while avoiding the influence of the evaporation unit 5 accompanied by heat absorption. Further, as shown in FIG. 1, the reforming unit 4 is disposed above the stack 2, and the evaporation unit 5 is disposed below the stack 2. For this reason, the reforming part 4 and the evaporation part 5 are not approaching excessively. Therefore, the liquid reforming water in the evaporation unit 5 is suppressed from being sent to the reforming unit 4, and the reforming catalyst and carrier of the reforming unit 4 are suppressed from being deteriorated by the liquid reforming water.

  If the purification catalyst of the purification unit 66 is maintained at a temperature considerably higher than its activation temperature region, there is a risk of deterioration. In this regard, according to the present embodiment, the purification unit 66 is cooled by the heat of vaporization of the evaporation unit 5. For this reason, overheating of the carrier and the purification catalyst accommodated in the purification unit 66 is suppressed, and the life of the carrier and the purification catalyst is extended. The reforming water is a liquid and has a high specific heat, and therefore has a high cooling capacity.

  Moreover, according to this embodiment, the purification | cleaning part 66 is arrange | positioned rather than the height of the water surface 56w of the reforming water 56 stored in the water storage part 52. FIG. Therefore, in the height direction (arrow H direction), the purification unit 66 and the water storage unit 52 are shifted from each other, and the purification unit 66 does not overlap the water storage unit 52. For this reason, the rapid cooling of the purification catalyst of the purification unit 66 by the heat of vaporization of the liquid reforming water of the water storage unit 52 is suppressed. Therefore, excessive cooling of the purification unit 66 is suppressed while the evaporation unit 5 performs mild cooling of the entire purification unit 66. For this reason, it is advantageous to maintain the purification catalyst of the purification unit 66 in the active temperature region.

  However, the height of the reformed water stored in the water storage unit 52 may correspond to the purification unit 66 depending on the type of the carrier and the purification catalyst. That is, in the height direction, the purification unit 66 and the water storage unit 52 may be positioned at the same level, and the purification unit 66 may overlap the water storage unit 52. In this case, the purification catalyst of the purification unit 66 is directly cooled by the heat of vaporization of the liquid reforming water in the water storage unit 52, which can contribute to the suppression of overheating of the purification unit 66. Note that, if necessary, the purification unit 66 and the evaporation unit 5 may be integrated into a united assembly, and the assembly may be detachable from the exhaust gas passage 6.

(Embodiment 2)
FIG. 3 shows a second embodiment. This embodiment has basically the same configuration and the same operation and effect as the first embodiment. In the following, different parts will be mainly described. The outer peripheral side of the purification unit 66 in the radial direction (arrow DA direction) is cooled in the vaporization chamber 50 of the evaporation unit 5. For this reason, when the dimension of the purification part 66 in the exhaust gas flow direction is L and the diameter dimension of the purification part 66 is D, if L / D is small, the purification part 66 is purified in the radial direction (arrow DA direction). Since the variation in temperature between the outer peripheral portion and the central region of the portion 66 increases, there is room for improvement in order to make the purification effect uniform.

  In this regard, according to the present embodiment, as shown in FIG. 3, the axial length of the purifying unit 66 is increased. That is, for the purification unit 66, the dimension L in the exhaust gas flow direction is increased, the diameter D is decreased, and as a result, the value of L / D is increased to 1 or more, for example, 1.5 or more, 2 or more, 3 As mentioned above, it is increased to 4 or more. For this reason, the dispersion | variation in the temperature of an outer peripheral part and a center area in the radial direction of the purification | cleaning part 66 is suppressed. In this case, it can contribute to the uniform purification effect in the radial direction (arrow DA direction).

  However, as described above, when the value of L / D is increased, the length of the purification unit 66 becomes longer, so the downstream region 66d with respect to the temperature of the upstream region 66u (one end side in the length direction) of the purification unit 66. The temperature on the other end side in the length direction tends to increase. This is because the purification reaction of the purification unit 66 is an oxidation reaction and generates heat. In this regard, according to this embodiment, the exhaust gas flows downward (in the directions of arrows A2 and A3) with respect to the purification unit 66, whereas the reforming water and / or water vapor in the evaporation unit 5 is upward (in the direction of arrow E). , Flows in the direction opposite to the exhaust gas flow direction). For this reason, the flow of exhaust gas and the flow of reforming water and / or steam are counterflows in opposite directions. For this reason, as low as possible reformed water and / or water vapor (upstream region 5 u of the evaporation unit 5) in the evaporation unit 5 faces the downstream region 66 d of the purification unit 66 that tends to be relatively hot. For this reason, it becomes advantageous in suppressing the overheating of the downstream region 66d that tends to be relatively high in the purification unit 66. In this sense, it is possible to contribute to extending the life of the purification catalyst in the downstream region 66d, and the temperature variation in the exhaust gas flow direction in the purification unit 66 is also reduced. Note that, if necessary, the purification unit 66 and the evaporation unit 5 may be integrated into a united assembly, and the assembly may be detachable from the exhaust gas passage 6.

(Embodiment 3)
FIG. 4 shows a third embodiment. This embodiment basically has the same configuration and the same operation and effect as the above-described embodiment. In the following, different parts will be mainly described. The water storage section 52 of the evaporation section 5 includes a first water storage section 52f and a second water storage section 52s communicating with the first water storage section 52f. The reformed water in the first water reservoir 52f is heated by the exhaust gas in the exhaust gas passage 6. Between the second water reservoir 52s and the exhaust gas passage 6, a heat insulating layer 52m formed of an air heat insulating layer is formed. For this reason, although the heat of the exhaust gas flowing through the exhaust gas passage 6 is transmitted to the reformed water in the first water reservoir 52f, it is not directly transmitted to the second water reservoir 52s. Therefore, the reforming water in the second water storage section 52f becomes preliminary water. Therefore, even if the power generation conditions of the stack 2 change suddenly, water drainage in the evaporation unit 5 is suppressed by the reformed water 56 of the second water storage unit 52s. The heat insulating layer 52m is not limited to the air heat insulating layer, and may be formed of a heat insulating material. Note that, if necessary, the purification unit 66 and the evaporation unit 5 may be integrated into a united assembly, and the assembly may be detachable from the exhaust gas passage 6.

(Embodiment 4)
FIG. 5 shows a fourth embodiment. This embodiment basically has the same configuration and the same operation and effect as the above-described embodiment. In the following, different parts will be mainly described. As shown in FIG. 5, in the height direction (arrow H direction), the water storage part 52 of the evaporation part 5 is provided at a position facing the purification part 66 through the surrounding wall part 51. That is, the water storage part 52 and the purification | cleaning part 66 are arrange | positioned in the position which mutually opposes via the surrounding wall part 51. FIG. Therefore, the heat generated by the purification reaction in the purification unit 66 can be quickly transmitted to the liquid reforming water 56 in the water storage unit 52. For this reason, not only the steaming of the reforming water 56 is promoted, but also it can contribute to suppressing the overheating of the purification unit 66. Therefore, the thermal deterioration of the carrier of the purification unit 66 and the purification catalyst is effectively suppressed. When the purification unit 66 is too cold at the time of start-up, a heater may be provided so that the heat generated by the heater is transferred to the purification unit 66. It is preferable that the reforming water 56 does not exist in the water storage section 52 at the time of startup. The purification unit 66 and the evaporation unit 5 may be integrated into a united assembly, and the assembly may be detachable from the exhaust gas passage 6.

(Embodiment 5)
FIG. 6 shows a fifth embodiment. This embodiment basically has the same configuration and the same operation and effect as the above-described embodiment. In the following, different parts will be mainly described. FIG. 6 shows a passage forming member 600 that forms part of the passage portion 64 of the exhaust gas passage 6. The passage forming member 600 is a unitized assembly and can be attached to and detached from the passage portion 64 of the exhaust gas passage 6. The passage forming member 600 has a cylindrical surrounding wall portion 604 made of a metal having a passage 603 for allowing exhaust gas to pass therethrough, and a gas permeable purification portion that is disposed coaxially with the passage 603 and has a purification catalyst. 66 and a cylindrical evaporation section 5 that is coaxially formed on the outer peripheral portion of the cylindrical surrounding wall section 604 and forms a cylindrical vaporization chamber 50. The cylindrical surrounding wall portion 604 has an upper first flange 601 (first attachment portion) and a lower second flange 602 (first attachment portion).

  As shown in FIG. 6, the height position of the water storage section 52 is overlapped with the height position of the purification section 66 so that the water storage section 52 of the vaporization chamber 50 faces the purification section 66. Accordingly, during the power generation operation, the purification unit 66 is effectively cooled by the reforming water 56 of the water storage unit 52, and overheating of the purification unit 66 is suppressed. Considering that the purification reaction is accompanied by heat generation, the downstream region 66d of the purification unit 66 has a higher temperature than the upstream region 66u. According to the present embodiment, the water reservoir 52 that stores the reformed water 56 is opposed to the downstream region 66d, and is located at substantially the same height as the downstream region 66d. For this reason, overheating of the downstream region 66d, which tends to be high temperature, is suppressed.

  An outer wall 59 outside the cylindrical surrounding wall portion 604 communicates with the vaporizing chamber 50 and is supplied to the water supply port 53 through which reforming water is supplied to the vaporizing chamber 50, and is generated in the vaporizing chamber 50. And a discharge port 55 for discharging the steam. In addition, although the discharge port 55 is located above the water supply port 53, it is not limited to this. The first flange 601 has a plurality of first mounting holes 631. The second flange 602 has a plurality of second mounting holes 632. When removing the cleaning portion 66 for maintenance, the first attachment 641 (only one is shown) inserted into the first attachment hole 631 is removed and the second attachment 642 inserted into the second attachment hole 632 is removed. Remove (only one is shown). As a result, the passage forming member 600 having the purifying portion 66 is removed from the mating flange 690 and the mating flange 695 of the piping of the exhaust gas passage 6. The mating flange 690 has a ring-shaped seal portion 691. The mating flange 695 has a ring-shaped seal portion 696. After the purification unit 66 is replaced with a new one or maintained, the purification unit 66 is inserted into the passage 603. The purifying part 66 is positioned by being engaged with a stopper 66x protruding near the bottom of the cylindrical surrounding wall part 604.

  In this state, the first attachment 641 (only one is shown) is inserted into the attachment hole 693 and the first attachment hole 631, and the second attachment 642 (only one is shown) is inserted into the attachment hole 698 and the second attachment hole 632. Insert it. Thus, the first flange 601 of the passage forming member 600 having the purification section 66 is detachably attached to the mating flange 690 of the exhaust gas passage 6 and the second flange 602 is attached to the mating flange 695 of the exhaust gas passage 6. Removably attach. Since the path portion 64 is formed with an expandable / contractible bellows part 64k, the detachability of the path forming member 600 is ensured. As described above, according to the present embodiment, the purification unit 66 and the evaporation unit 5 are integrally assembled into a united product, and the product is detachably attached to the exhaust gas passage 6. . In this case, it is advantageous for maintenance.

  As shown in FIG. 6, the upper portion of the vaporizing chamber 50 faces the first flange 601 and the lower portion faces the second flange 602. Therefore, the vaporizing chamber 50 can cool the metal flanges 601 and 602. For this reason, overheating of the seal portions 691 and 696 formed of the seal material held by the flanges 601 and 602 is suppressed, and the durability of the seal portions 691 and 696 is improved. In the radial direction (arrow DA direction), since the vaporizing chamber 50 is located at substantially the same position as the seal portions 691 and 696, the seal portions 691 and 696 are efficiently cooled. The seal portions 691 and 696 may be held by the first flanges 601 and 602. According to the present embodiment, the height position of the water storage section 52 overlaps with the position of the downstream region 66d of the purification section 66, and the water storage section 52 faces the purification section 66, but this is not restrictive. But it ’s okay.

(Embodiment 6)
FIG. 7 shows a sixth embodiment. The present embodiment basically has the same configuration and the same function and effect as the fifth embodiment described above. A heat insulating layer 66t partitioned by a wall 66tm is formed between the vaporizing chamber 50 and the purification unit 66. The wall 66tm and the heat insulating layer 66t are coaxially provided so as to cover the outer periphery of the purification unit 66 and are an air heat insulating layer, but are formed of a heat insulating material such as asbestos, glass fiber, ceramics, and the like. May be. For example, when the active temperature region of the purification catalyst held in the purification unit 66 is relatively high, the purification unit 66 is cooled with the reforming water and / or water vapor in the vaporization chamber 50 in the power generation operation of the stack. In some cases, however, it is preferable to cool gently rather than quench. The heat insulating layer 66t is advantageous for cooling the purification part 66 mildly.

(Embodiment 7)
FIG. 8 shows a seventh embodiment. This embodiment basically has the same configuration and the same operation and effect as the above-described embodiment. At least a portion 57e of the water vapor passage 57 is adjacent to the exhaust gas passage 6 formed inside the fuel cell device 1 so that heat can be transferred. The water vapor passage 57 is preferably separated from the cathode gas passage 7. For this reason, the water vapor flowing through the water vapor passage 57 toward the inlet port 4i of the reforming section 4 can be heated by the exhaust gas in the exhaust gas passage 6, which is advantageous in improving the reforming efficiency of the reforming section 4. Further, the water vapor flowing through the water vapor passage 57 toward the inlet port 4 i of the reforming unit 4 is suppressed from being cooled and condensed, and liquid condensed water is prevented from being supplied to the reforming unit 4.

(Other)
The present invention is not limited only to the embodiment described above and shown in the drawings, and can be implemented with appropriate modifications within a range not departing from the gist. The structure of the fuel cell device 1 is not limited to the structure shown in the drawings. The stack 2 is provided in two rows so as to sandwich the third passage 73 of the cathode gas passage 7, but is not limited thereto, and may be one row, three rows, or four rows. The stack has a laminated structure formed by assembling flat anodes and cathodes. However, the stack is not limited thereto, and may be a tube type in which the anode, the electrolyte, and the cathode are wound in a roll shape. The pump described above may be a compressor or a fan. The fuel material may be gaseous or liquid. The following technical idea can also be grasped from the description of this specification.

  [Additional Item 1] An evaporation unit that vaporizes reformed water to generate water vapor, a reforming unit that reforms a fuel material with the water vapor generated in the evaporation unit to generate anode gas, and the reforming unit A solid oxide fuel cell that generates electric power with the anode gas and the cathode gas generated in step 1, and an exhaust gas passage that discharges exhaust gas generated during the power generation operation of the fuel cell. The evaporating section has a water vapor generating vaporization chamber provided to receive the exhaust heat of the exhaust gas flowing through the exhaust gas passage. The evaporation section can be operated by exhaust heat of the exhaust gas.

  [Additional Item 2] In Additional Item 1, a purification unit having a purification catalyst for purifying the exhaust gas by reducing an environmental influence component contained in the exhaust gas flowing through the exhaust gas passage is provided in the exhaust gas passage. The fuel cell system. The heat generated by the purification reaction of the purification unit can be transmitted to the evaporation unit.

  The present invention can be used in, for example, fuel cell systems for stationary use, vehicles, electronic equipment, and electrical equipment.

  1 is a fuel cell device, 2 is a stack, 20 is a fuel cell, 21 is an anode, 22 is a cathode, 3 is a shell, 30 is a power generation chamber, 4 is a reforming unit, 27 is a combustion unit, 28 is a combustion flame, 40 is a reforming water system, 41 is a water purifier, 413 reforming water supply passage, 44 is a reforming water pump, 42 is a reforming water tank, 5 is an evaporating section, 50 is a vaporizing chamber, 51 is a surrounding wall section, 52 Is a water storage section, 57 is a water vapor passage, 95 is a cathode gas supply system, 96 is a cathode gas supply passage, 97 is a cathode gas pump, 8 is a hot water storage system, 80 is a hot water storage tank, 82 is a hot water storage pump (water transport source), 83 is A heat exchanger for hot water storage, 6 is an exhaust gas passage, 63 is a confluence passage, 64 is a passage portion, 66 is a purification portion, 67 is a flow passage restriction portion, 7 is a cathode gas passage, 81 is a first heat insulating layer, and 82 is a first passage 2 shows a heat insulation layer.

Claims (7)

Electric power is generated by an evaporator that vaporizes reformed water to generate water vapor, a reformer that reforms a fuel material with water vapor generated in the evaporator and generates anode gas, and the anode gas and cathode gas Included in the solid oxide fuel cell, an exhaust gas passage for exhausting exhaust gas generated during power generation operation of the fuel cell, and the exhaust gas provided in the exhaust gas passage and flowing through the exhaust gas passage A purification unit having a purification catalyst for purifying the exhaust gas by reducing environmental impact components,
The evaporating unit includes a vapor generation chamber for generating water vapor provided to receive exhaust heat of exhaust gas flowing through the exhaust gas passage and reaction heat of the purification catalyst.   In Claim 1, the heat insulation layer is provided between the said fuel cell and the said evaporation part, and the said heat insulation layer improves the heat insulation between the said fuel cell and the said evaporation part, and the said evaporation. The fuel cell system which uses as a base material the heat insulation material which suppresses the influence which the vaporization heat of a part gives to the said fuel cell.   3. The evaporation unit according to claim 1, wherein the evaporation unit includes a water storage unit that communicates with the vaporization chamber and stores liquid reforming water, and the water storage unit faces the purification unit so as to remove heat from the purification unit. Fuel cell system.   In Claim 3, the passage portion of the exhaust gas passage has a flow passage restriction portion that is located downstream of the purification portion and has a flow passage cross-sectional area smaller than a flow passage cross-sectional area upstream of the purification portion, The fuel cell system in which the water storage cross-sectional area of the water storage section is increased by the flow path restricting section. 5. The hot water storage system according to claim 1, wherein the hot water storage system circulates the hot water storage tank, a circulation passage for circulating water in the hot water storage tank, and water in the circulation passage. A water transfer source, and the hot water storage heat exchanger that heats the water in the circulation passage by exchanging heat between the water in the circulation passage and the exhaust gas in the exhaust gas passage,
The evaporation unit is a fuel cell system arranged between the hot water storage heat exchanger and the fuel cell.   6. The passage portion of the exhaust gas passage according to claim 1, wherein the passage portion of the exhaust gas passage has a passage forming member that can be attached to and detached from the exhaust gas passage. A cylinder having a passage to be passed through, the purification unit having gas permeability disposed in the passage and having the purification catalyst, and the evaporation unit which is adjacent to the cylinder and forms the vaporization chamber. The fuel cell system.   The fuel cell system according to claim 1, wherein a heat insulating layer is disposed between the vaporization chamber and the purification unit.

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