JP6507869B2 - Fuel cell module - Google Patents

Description

  The present invention relates to a fuel cell module in which a fuel cell stack is supported by legs.

  High-temperature fuel cell modules that perform reactions at about 600 ° C to 1000 ° C, such as solid oxide fuel cells (SOFCs) and molten carbonate fuel cells (MCFCs), in order to maximize their power generation performance It is necessary to maintain the fuel cell stack in a proper temperature profile.

  For example, in Patent Document 1, the fuel cell stack is accommodated in a heat insulating case to perform battery heat retention, and fuel and air before introducing the stack are circulated in heat exchangers installed on the side and upper portions of the fuel cell stack. There is disclosed a structure in which the fuel and air are preheated by radiant heat from the fuel cell stack, thereby improving the thermal efficiency of the entire module and improving the power generation efficiency.

JP 2007-157480 A

  In the fuel cell module as described above, the installation structure in which the fuel cell stack is supported by the legs is generally used, and even in the configuration of Patent Document 1, the pedestal on which the fuel cell stack is mounted is supported by the legs.

  By the way, since such a leg is usually made of metal such as stainless steel or steel in consideration of strength and heat resistance, the heat generated in the fuel cell stack is directly and smoothly applied to the leg by heat conduction. It will be transmitted. As a result, a heat loss due to heat radiation from the legs to the outside is generated to reduce the thermal efficiency of the entire module, which is a barrier for improving the power generation efficiency.

  The present invention has been made in consideration of the above-described conventional problems, and it is an object of the present invention to provide a fuel cell module capable of reducing the heat radiation from the legs supporting the fuel cell stack to the outside and improving the thermal efficiency. To aim.

  A fuel cell module according to the present invention comprises a fuel cell stack, a fuel preheater preheating fuel introduced into the fuel cell stack, and an air preheater preheating air introduced into the fuel cell stack. A fuel cell module in which the fuel cell stack is supported by legs, wherein the heat transmitted to the legs is introduced into the fuel and the air preheater before being introduced into the fuel preheater. It is characterized in that a heat recovery unit is provided which recovers using at least one of the air before being discharged.

  According to such a configuration, in the leg portion supporting the fuel cell stack, the heat transmitted to the leg portion is not introduced into the fuel preheater and the air before it is introduced into the fuel preheater and the air preheater. And a heat recovery unit for recovery using at least one of the above. As a result, the heat transferred from the fuel cell stack to the legs can be recovered by the heat recovery unit as fuel and air, and can be effectively used for preheating the fuel and air. As a result, it is possible to reduce the heat loss due to the heat generated in the fuel cell stack being dissipated from the legs to the outside, improve the thermal efficiency of the entire module, and improve the power generation efficiency.

  The fuel cell stack, the fuel preheater, the air preheater, and the leg portion provided with the heat recovery portion may be accommodated in a heat insulating casing. Then, the temperature in the fuel cell module can be maintained to further enhance the thermal efficiency, and the heat recovery portion can reduce the heat loss from the leg portion to the outside of the heat insulating casing.

  When the heat recovery unit is configured integrally with the leg, attachment to the fuel cell stack is easy, and heat transferred to the leg can be recovered with high efficiency.

  A plurality of the leg portions are provided, and the heat recovery portion is provided in at least two of the leg portions, and the heat recovery portion provided in one leg portion supplies the fuel to the fuel cell stack A fuel supply line may be connected, and an air supply line for supplying the air to the fuel cell stack may be connected to the heat recovery unit provided in the other leg.

  According to the present invention, the heat transferred from the fuel cell stack to the leg can be recovered by the heat recovery unit with fuel and air, and can be effectively used for preheating the fuel and air. As a result, it is possible to reduce the heat loss due to the heat generated in the fuel cell stack being dissipated from the legs to the outside, improve the thermal efficiency of the entire module, and improve the power generation efficiency.

FIG. 1 is a front view schematically showing the configuration of a fuel cell module according to an embodiment of the present invention. FIG. 2 is a block diagram of the leg portion and the heat recovery portion provided in the leg portion, FIG. 2 (A) is a front view partially in section, and FIG. 2 (B) is an IIB in FIG. 2 (A). -It is sectional drawing in alignment with a IIB line. FIG. 3 is a block diagram of a leg according to a modification and a heat recovery portion provided in the leg, and FIG. 3 (A) is a front sectional view, and FIG. 3 (B) is a cross-sectional view of FIG. IIIB-IIIB line of FIG.

  Hereinafter, preferred embodiments of the fuel cell module according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a front view schematically showing a configuration of a fuel cell module 10 according to an embodiment of the present invention.

  As shown in FIG. 1, the fuel cell module 10 is provided with a fuel cell stack 12, a fuel preheater 14, and an air preheater 16, which are installed in the inside (high temperature chamber) of the heat insulation housing 18. is there. The fuel cell stack 12 is supported by a plurality of legs 20 and 21 standing from the floor surface of the heat insulating housing 18. The legs 20 and 21 may be configured as legs of a gantry having a table plate (not shown) on which the fuel cell stack 12 is mounted.

  The fuel cell stack 12 is a cell stack provided with a plurality of power generation cells that generate electricity by reacting the fuel (fuel gas) introduced from the fuel supply line LF1 with the air introduced from the air supply line LA1. Fuel exhaust gas (anode off gas) and air exhaust gas (cathode off gas) discharged from the fuel cell stack 12 are discharged to the outside from the fuel discharge line LF2 and the air discharge line LA2, respectively.

  The fuel cell stack 12 can use a known configuration such as, for example, a configuration in which a plurality of cylindrical power generation cells are bundled or a configuration in which a plurality of rectangular flat power generation cells are stacked. The fuel cell stack 12 of this embodiment uses a solid oxide fuel cell (SOFC) in which ion conductive ceramics are interposed as an electrolyte between a fuel electrode (anode) and an air electrode (cathode).

  Gas paths 22 and 23 are provided at the upper and lower portions of the fuel cell stack 12, respectively. The gas paths 22 and 23 include fuel and air introduced into the fuel cell stack 12 from the fuel supply line LF1 and the air supply line LA1, fuel discharged from the fuel cell stack 12 to the fuel discharge line LF2 and the air discharge line LA2, and It is a portion to be a manifold for distributing or collecting and circulating air. The gas paths 22 and 23 have a jacket structure formed in a box shape, for example, of a high strength and heat resistant metal plate such as stainless steel or steel.

  The legs 20 and 21 supporting the fuel cell stack 12 are fixed to the lower surface of the jacket of the gas path 23 at the bottom of the fuel cell stack 12 by bolting or welding. In the case of the present embodiment, one leg 20 is provided with a heat recovery portion 24 through which fuel flows before being introduced into the fuel preheater 14, and the other leg 21 is introduced into the air preheater 16. Although the heat recovery unit 25 through which the previous air flows is provided, the details will be described later. Although only the two legs 20 and 21 on the front side are illustrated in FIG. 1, about four to eight legs 20 and 21 are provided according to the outer shape of the fuel cell stack 12. Therefore, the heat recovery parts 24 and 25 may be installed on one leg 20 and 21 respectively, or may be installed on two or more legs 20 and 21 respectively.

  A fuel supply line LF1 between the heat recovery unit 24 and the fuel cell stack 12 and a fuel discharge line LF2 from the fuel cell stack 12 are connected to the fuel preheater 14. The fuel preheater 14 is a heat exchanger that preheats the fuel introduced into the fuel cell stack 12 using the fuel exhaust gas discharged from the fuel cell stack 12 and the radiant heat from the fuel cell stack 12.

  Connected to the air preheater 16 are an air supply line LA1 between the heat recovery unit 25 and the fuel cell stack 12 and an air discharge line LA2 from the fuel cell stack 12. The air preheater 16 is a heat exchanger that preheats the air introduced into the fuel cell stack 12 using the exhaust gas of the air discharged from the fuel cell stack 12 and the radiant heat from the fuel cell stack 12.

  The heat insulating case 18 is a box body filled with a general heat insulating material such as glass wool on the outer wall surface, and can house the fuel cell stack 12 and the like inside with heat insulation and air tightness. The heat insulating material may be filled not only on the outer wall surface of the heat insulating housing 18 but also on the entire inside thereof.

  FIG. 2 is a configuration diagram of the leg portion 20 (21) and the heat recovery portion 24 (25) provided thereto, and FIG. 2 (A) is a partial cross-sectional front view, and FIG. It is sectional drawing in alignment with the IIB-IIB line | wire in FIG. 2 (A).

  As shown in FIGS. 2A and 2B, the leg portion 20 is housed and arranged in a leg body 30 serving as a strength member for supporting the fuel cell stack 12 and a recess 30a of the leg body 30, The heat recovery unit 24 is in close contact with and fixed to the 30 wall surfaces.

  The leg body 30 needs strength and heat resistance capable of stably supporting the fuel cell stack 12 having a high temperature of about 900 ° C. and the gas path 23 having a temperature of about 500 ° C. in the lower part thereof. And H-shaped steel and C-shaped steel. Since the leg main body 30 is fixed to the lower surface of the jacket of the gas path 23 at the lower part of the fuel cell stack 12 by bolting or welding, the heat conduction from the fuel cell stack 12 and the gas path 23 to the metal member and the metal member The heat is transferred by the heat transfer to reach, for example, about 500.degree. C. at the hottest part.

  The heat recovery unit 24 is a heat exchanger that recovers the heat transferred from the fuel cell stack 12 and the gas path 23 to the leg main body 30 by the fuel before being introduced into the fuel cell stack 12. The heat recovery unit 24 includes a container 32 in which the fuel flows, an inlet port 34 for introducing the fuel into the container 32, and an outlet port 36 for discharging the fuel out of the container 32.

  The inlet port 34 is provided on the lower side surface of the container 32 and is connected to a fuel supply line LF1 from a source external to the heat insulating housing 18 (see FIG. 1). The outlet port 36 is provided on the upper side surface of the container 32 and is connected to the fuel supply line LF1 directed to the inlet side of the fuel preheater 14 (see FIG. 1).

  The container 32 is formed in a box shape, for example, of a metal plate having high strength and heat resistance, such as stainless steel or steel. The wall surface of the container 32 is closely fixed to the inner wall surface of the recess 30 a of the leg main body 30, and one side wall is also used by the side wall surface 30 b of the leg main body 30. High heat exchange performance is secured. Inside the container 32, a plurality of heat transfer fins 38 for expanding the contact area with the fuel are provided at predetermined intervals in the vertical direction from the lower inlet port 34 side toward the upper outlet port 36 side. It is stacked. Each heat transfer fin 38 is formed with a large number of through holes 38a penetrating the plate thickness (see FIG. 2B). For the heat transfer fins 38, for example, a punching metal in which a large number of through holes are punched and formed in a thin metal plate is used.

  The fuel introduced into the vessel 32 from the inlet port 34 in the heat recovery unit 24 flows into the gas distribution unit 32 a which is a buffer space formed in the lower part in the vessel 32, and the respective heat transfer fins 38 stacked from there. Heat exchange with the leg main body 30 while passing through the through holes 38a. As a result, the heat of the leg main body 30 is recovered and the heated fuel is discharged from the gas collecting portion 32 b which is a buffer space formed in the upper portion of the container 32 to the outlet port 36 and then introduced into the fuel preheater Be done. The gas distribution portion 32a is a portion for reducing the flow velocity of the fuel introduced into the container 32 to evenly disperse the fuel in the surface direction of each heat transfer fin 38, and is filled with alumina balls or the like to be used as the fuel. The flow rate reduction may be promoted.

  The other leg portion 21 and the heat recovery portion 25 provided thereon are the same as the leg portion 20 and the heat recovery portion 24 shown in FIGS. 2A and 2B except that they have a symmetrical structure. It may be a structure. That is, in the leg portion 21, the heat recovery portion 25 is provided in the recess 30 a of the leg main body 30. The heat recovery unit 25 is provided with a container 32 through which the air flows, an inlet port 34 for introducing air into the container 32, and an outlet port 36 for discharging air from the container 32. Heat transfer fins 38 are stacked.

  Therefore, in the fuel cell module 10 configured as described above, the raw fuel gas (for example, hydrocarbon-based fuel such as natural gas, LPG or city gas) that has flowed from the external supply source to the fuel supply line LF1 The heat flows into the heat recovery part 24 of the part 20, recovers the heat transmitted from the fuel cell stack 12 to the leg main body 30 of the leg 20, is preheated, and then flows into the fuel preheater 14. The fuel introduced into the fuel preheater 14 exchanges heat with the fuel exhaust gas discharged from the fuel electrode of the fuel cell stack 12 through the gas path 23 to the fuel discharge line LF2 to be further preheated, and then the gas path 22 It is introduced into the fuel electrode of the fuel cell stack 12 via the fuel cell.

  On the other hand, the air (oxidant gas) circulated from the external supply source to the air supply line LA1 flows into the heat recovery unit 25 of the leg portion 21 and the heat transmitted from the fuel cell stack 12 to the leg main body 30 of the leg portion 21 Are collected and preheated, and then flow into the air preheater 16. The air introduced into the air preheater 16 exchanges heat with the air exhaust gas discharged from the air electrode of the fuel cell stack 12 to the air discharge line LA2 through the gas path 22 and is further preheated, and then the gas path 23 It is introduced into the air electrode of the fuel cell stack 12 via the fuel cell stack 12.

  As a result, in the fuel cell module 10, the power generation reaction is continued by the fuel and air after preheating introduced into the fuel electrode and the air electrode of the fuel cell stack 12 in this manner, and a high temperature of about 900 ° C. is maintained. Power generation operation is continued. The fuel cell module 10 shown in FIG. 1 is configured to introduce fuel preheated by the heat recovery unit 24 and the fuel preheater 14 into the fuel cell stack 12 and reform the fuel cell stack 12 internally. The fuel supply line LF1 between the fuel preheater 14 and the fuel cell stack 12 may be provided with a reformer.

  At this time, the heat transferred to the legs 20 and 21 is introduced to the fuel and air preheater 16 before being introduced to the fuel preheater 14 in the legs 20 and 21 supporting the fuel cell stack 12. Heat recovery units 24 and 25 are provided to recover using the previous air. Heat and heat transferred from the fuel cell stack 12 and the gas path 23 to the metal legs 20 and 21 which are heated to a high temperature by the heat recovery unit 24 and 25 are recovered by fuel and air, and are effective for preheating the fuel and air. It can be used to

  Therefore, according to the fuel cell module 10, the heat loss due to the heat generated in the fuel cell stack 12 being radiated from the legs 20, 21 to the outside of the heat insulating casing 18 is reduced, and the thermal efficiency of the entire module is improved. The power generation efficiency can be improved.

  Further, since the heat recovery portion 24 is integrally formed with the leg portion 20 (the leg main body 30), attachment to the fuel cell stack 12 is easy, and heat transferred to the leg portion 20 is recovered with high efficiency. can do.

  Note that the heat recovery units 24 and 25 provided in each of the legs 20 and 21 do not necessarily have to circulate both the fuel and the air, and any one of the fuel and the air, for example, a preheat that is larger than the fuel in general. Only the air requiring heat may be circulated. In addition, the heat recovery portions 24 and 25 may be provided only in a part of the legs 20 and 21 supporting the fuel cell stack 12, but the amount of heat released to the outside can be further reduced, and a more sufficient amount of heat can be obtained. It is preferable to provide the heat recovery portions 24 and 25 in all the legs 20 and 21 in order to recover the fuel into the fuel and the air.

  By the way, in the above, although the leg parts 20 and 21 which constituted both integrally by connecting and fixing the heat recovery part 24 (25) to the leg main body 30 were illustrated, a leg main body and a heat recovery part are structurally The integrated legs 20A and 21A (see FIG. 3) may be used.

  FIG. 3 is a configuration diagram of a leg 20A (21A) according to a modification and a heat recovery unit 24A (25A) provided thereto, and FIG. 3 (A) is a front sectional view, FIG. 3 (B) Fig. 3 is a cross-sectional view taken along the line IIIB-IIIB in Fig. 3 (A).

  As shown in FIGS. 3A and 3B, the leg portion 20A is a leg main body 40 serving as a strength member for supporting the fuel cell stack 12 and a heat recovery portion provided in the internal space of the leg main body 40. And 24A.

  The leg body 40 needs strength and heat resistance that can stably support the fuel cell stack 12 having a high temperature of about 900 ° C. and the gas path 23 having a temperature of about 500 ° C. in the lower part thereof. Etc. are formed of cylindrical steel or square cylindrical steel. Since the leg main body 40 is fixed to the lower surface of the jacket of the gas path 23 at the lower part of the fuel cell stack 12 by bolting or welding, the heat conduction from the fuel cell stack 12 and the gas path 23 to the metal member and the metal member The heat is transferred by the heat transfer to reach, for example, about 500.degree. C. at the hottest part.

  The heat recovery portion 24A is configured such that the cylindrical leg main body 40 is a jacket, and the heat transmitted from the fuel cell stack 12 and the gas path 23 to the leg main body 40 is recovered by the fuel before being introduced into the fuel cell stack 12 It is an exchanger. The heat recovery portion 24A is formed by the internal space of the leg main body 40, and the container 42 through which the fuel flows, the inlet port 34 for introducing the fuel into the container 42, and the outlet port for discharging the fuel out of the container 42 And 36.

  Since the container 42 is formed on the inner wall surface of the leg main body 40, high heat exchange performance is secured between the fuel flowing inside and the leg main body 40. The inside of the container 42 is filled with a large number of metal balls 44 for expanding the contact area with the fuel. The metal ball 44 is a metal sphere such as aluminum. The heat transfer fins 38 similar to the legs 20 described above may be used instead of the metal balls 44.

  The fuel introduced into the container 42 from the inlet port 34 in the heat recovery unit 24A exchanges heat with the leg main body 40 while passing through the gaps between the metal balls 44 filled in the container 42. As a result, the heat of the leg body 40 is recovered and the heated fuel is discharged to the outlet port 36 at the top of the vessel 42 and subsequently introduced to the fuel preheater 14.

  The other leg portion 21A and the heat recovery portion 25A provided thereon are provided with the leg portion 20A and the heat recovery portion 24A, and the inlet port 34 and the outlet port 36 shown in FIGS. 3 (A) and 3 (B). The same structure may be used except that the position is symmetrical. That is, in the leg portion 21A, the heat recovery portion 25A is provided inside the leg main body 40. The heat recovery unit 25A is provided with a container 42 through which the air flows, an inlet port 34 for introducing air into the container 42, and an outlet port 36 for discharging the air from the container 42. Metal balls 44 are filled.

  In addition, this invention is not limited to above-described embodiment, Of course, it can change freely in the range which does not deviate from the main point of this invention.

  For example, in the above embodiment, a configuration using a solid oxide fuel cell (SOFC) as the fuel cell stack 12 has been exemplified, but the present invention relates to a fuel cell having another structure, for example, a molten carbonate fuel cell (MCFC) Is also applicable. Further, in the case of these high temperature SOFCs and MCFCs, it is preferable to form a high temperature chamber using the heat insulating case 18 and maintain the high temperature to secure the thermal efficiency, but depending on the required performance and specifications of the module, the heat insulating case 18 may be omitted. Also in this case, by using the legs 20 and 21 (20A and 21A) provided with the heat recovery units 24 and 25 (24A and 25A) as described above, the amount of heat released to the outside is reduced, and the module thermal efficiency Can be improved.

DESCRIPTION OF SYMBOLS 10 fuel cell module 12 fuel cell stack 14 fuel preheater 16 air preheater 18 heat insulation housing | casing 20, 20A, 21, 21A leg part 22,23 gas path 24, 24A, 25, 25A heat recovery part 30, 40 leg main body 32 , 42 container 34 inlet port 36 outlet port 38 heat transfer fin 44 metal ball LA1 air supply line LA2 air discharge line LF1 fuel supply line LF2 fuel discharge line

Claims (4)

A fuel cell stack, a fuel preheater preheating fuel introduced into the fuel cell stack, and an air preheater preheating air introduced into the fuel cell stack, the fuel cell stack being supported by legs Fuel cell module, and
In the leg portion, heat recovery is performed using at least one of fuel before being introduced into the fuel preheater and air before being introduced into the air preheater, for heat transferred to the leg portion. A fuel cell module comprising: In the fuel cell module according to claim 1,
A fuel cell module characterized in that the fuel cell stack, the fuel preheater, the air preheater, and the leg portion provided with the heat recovery portion are accommodated in a heat insulation casing. In the fuel cell module according to claim 1 or 2,
The fuel cell module according to claim 1, wherein the heat recovery unit is integrally formed with the leg. The fuel cell module according to any one of claims 1 to 3.
A plurality of the leg portions are provided, and the heat recovery portion is provided on at least two of the leg portions,
A fuel supply line for supplying the fuel to the fuel cell stack is connected to a heat recovery unit provided in one of the legs.
A fuel cell module characterized in that an air supply line for supplying the air to the fuel cell stack is connected to a heat recovery part provided in the other leg.

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