JP2011100640A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell capable of reaching a reaction gas uniformly over a whole of a gas manifold and supplying the reaction gas uniformly to a whole of fuel battery cells. <P>SOLUTION: The fuel cell 1 is provided with a plurality of fuel battery cells 84 inside which reaction gas passages are formed, a gas manifold 66 for housing a reaction gas, a supporting plate 68 which is provided on an upper part of the gas manifold 66 and supports one end of the fuel battery cells 84 in a reaction gas passage direction and moreover in which through-holes 69 for supplying the reaction gas in the gas manifold 66 to each of the reaction gas passages are formed, and an inner gas supply piping 63 which is provided inside the gas manifold 66 and supplies the reaction gas jetted from the plurality of jetting holes 65 for jetting the reaction gas to the inside of the gas manifold 66. The inner gas supply piping 63 is provided with a thermal deformation prevention means of which the axis core is arranged along a fuel battery cell supporting face of the supporting plate 68 with a distance to a bottom face 67 and which prevents a thermal deformation of the inner gas supply piping 63. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel cell including a plurality of fuel cells operated by a reaction gas (power generation gas).

  Conventionally, as a type of fuel cell, there is a solid oxide fuel cell (hereinafter also referred to as “SOFC”) provided with a plurality of fuel cells operated by a reaction gas. This SOFC usually includes a plurality of fuel cells arranged in a power generation chamber, supplies air as an oxidant gas supplied into the power generation chamber to the cathode electrode of the fuel cell, and the fuel cell. The anode electrode is configured so that a power generation reaction can be caused by supplying hydrogen gas as a fuel gas supplied through a gas manifold.

  Examples of such SOFCs include, for example, a gas dispersion chamber, a power generation chamber that is disposed above the gas dispersion chamber and has a plurality of fuel cells standing therein, and between the gas dispersion chamber and the power generation chamber. And a lower partition wall formed with a vent hole through which the fuel gas supplied to the gas dispersion chamber is circulated to the power generation chamber, and the fuel gas supplied to the gas dispersion chamber is passed through the vent hole What is supplied to the anode electrode of the fuel cell is introduced. (For example, refer to Patent Document 1).

  By the way, in SOFC, when fuel withering fuel cells or heat generation temperature unevenness occurs, there is a risk that the life of the fuel cells will be shortened or damaged, and in order to solve these problems, It is known that it is important to uniformly supply reaction gas (power generation gas) to all of them. The SOFC is required to reduce the energy required for power generation as much as possible, and this requirement is addressed by supplying the minimum necessary reaction gas to the fuel cell. Therefore, it is impossible to increase the supply amount of the reaction gas in the gas dispersion chamber (gas manifold) or increase the supply pressure of the reaction gas, and evenly distribute the reaction gas in the gas dispersion chamber (gas manifold) ( Diffusion) is becoming more difficult.

  Therefore, a plurality of fuel cells are arranged on the gas manifold, and a gas supply pipe for supplying fuel gas to the gas manifold is connected to a top plate (upper surface) of the gas manifold, and the gas supply By blowing the fuel gas supplied from the pipe onto the inner bottom surface of the gas manifold, the fuel gas is dispersed in the gas manifold, and the fuel gas is supplied almost uniformly to the anode electrode of the fuel cell. The fuel cell is also introduced. (For example, refer to Patent Document 2).

JP 2006-66387 A JP 2008-66127 A

  However, the fuel cell described in Patent Document 1 has a structure in which fuel gas is supplied to the gas dispersion chamber from one fuel gas supply pipe communicated with a substantially central portion of the bottom surface of the gas dispersion chamber. Therefore, the fuel gas has a slower flow rate as the position of arrival from the fuel gas supply pipe becomes farther, and it is difficult to sufficiently reach the fuel gas to every corner of the gas dispersion chamber. Accordingly, the fuel gas supplied from the vent hole formed near the center of the gas dispersion chamber among the vent holes formed in the lower partition wall disposed between the gas dispersion chamber and the power generation chamber. It is possible to supply a sufficient amount of fuel gas to the fuel cells that generate power by the fuel gas supplied from the vent hole formed at a position far from the center of the gas dispersion chamber. It is difficult to supply a sufficient amount of fuel gas to the fuel cell that generates power. For this reason, there is a possibility that the fuel gas cannot be uniformly supplied to all the fuel cells.

  Further, in the fuel cell described in Patent Document 2, since the gas supply pipe is connected to one end of the top plate of the gas manifold, the fuel gas flows from the fuel gas spraying position on the inner bottom surface of the gas manifold. The farther the reaching position is, the slower the flow velocity becomes, and it is difficult to make the fuel gas reach evenly throughout the gas manifold. Therefore, a sufficient amount of fuel gas can be supplied to the fuel cells arranged at a position close to the fuel gas spray position, but the fuel cell is disposed at a position far from the fuel gas spray position. It is difficult to supply sufficient fuel gas to the fuel cell. For this reason, there is a possibility that the fuel gas cannot be uniformly supplied to all the fuel cells.

  The present invention has been made in view of such circumstances, and can make the reaction gas reach evenly throughout the gas manifold, and can evenly supply the reaction gas to all the fuel cells. An object of the present invention is to provide a simple fuel cell.

  In order to achieve this object, the present invention provides a plurality of fuel cells each having a reaction gas flow path formed therein, a gas manifold for containing the reaction gas therein, and a horizontal arrangement above the gas manifold. And a support plate that supports one end of the plurality of fuel cells in the direction of the reaction gas flow path and has a through hole for supplying the reaction gas accommodated in the gas manifold to each of the reaction gas flow paths. And a plurality of ejection holes that are disposed inside the gas manifold and eject the reaction gas, and supply the reaction gas ejected from the ejection holes into the gas manifold. A gas supply pipe; and a thermal deformation preventing means for preventing thermal deformation of the internal gas supply pipe, and the internal gas supply pipe has a fuel cell support surface whose axis is the support plate. While being disposed along, there is provided the supporting plate opposite to the fuel cell formed by spaced bottom and spacing of the gas manifold.

  In the fuel cell having this configuration, an internal gas supply pipe having a plurality of ejection holes is disposed inside the gas manifold, and the axis of the internal gas supply pipe is the fuel cell support surface of the support plate. Therefore, the distance between the inner wall of the gas manifold and the internal gas supply pipe can be shortened, and the ejection hole can be arranged at an arbitrary position in the gas manifold. . Therefore, since the ejection hole can be positioned at an arbitrary position in the gas manifold, the ejection hole can be provided at an appropriate position in order to spread the reaction gas in the gas manifold, and the reaction gas is supplied to the gas manifold. It can be evenly distributed throughout the gas manifold. In addition, since the internal gas supply pipe is spaced from the bottom surface of the gas manifold, the reaction gas is dispersed along the bottom surface without being obstructed by the internal gas supply pipe. Can do. And it can also suppress that the heat | fever of the reaction gas which distribute | circulates the said internal gas supply piping is taken by the said bottom face.

  The support plate may be formed integrally with the manifold, or may be formed separately from the manifold.

  By the way, it is known that the inside of the gas manifold becomes high temperature (for example, about 500 ° C. to 600 ° C.) during power generation of the fuel cell, and is supplied to the inside of the gas manifold through the internal gas supply pipe. The temperature of the reaction gas is also high (for example, about 500 ° C. to 600 ° C.), and therefore the temperature of the internal gas supply pipe itself is also high (for example, about 500 ° C. to 600 ° C.). Here, since the fuel cell according to the present invention has a thermal deformation preventing means for preventing thermal deformation of the internal gas supply pipe, even if the internal gas supply pipe becomes hot, the internal gas supply pipe Can be prevented from being thermally deformed by its own weight. Accordingly, the reaction gas can be more evenly distributed throughout the gas manifold, and the reaction gas can be evenly supplied to the respective fuel cells.

  Further, in the fuel cell according to the present invention, the thermal deformation preventing means may include a rigidity reinforcing means that is formed in the internal gas supply pipe and that reinforces the rigidity of the internal gas supply pipe in the heat deformation direction. By configuring in this way, even if the internal gas supply pipe is subjected to a force to be thermally deformed downward by its own weight, the rigidity of the internal gas supply pipe in the heat deformation direction is high. Therefore, the internal gas supply pipe can be prevented from being thermally deformed.

  Further, as the rigidity enhancing means, there can be mentioned a structure in which a cross-sectional shape perpendicular to the axial direction of the internal gas supply pipe is longer in the vertical direction than in the horizontal direction. By comprising in this way, the rigidity of the said internal gas supply piping can be easily strengthened, without providing rigidity reinforcement means, such as a rib, separately in the said internal gas supply piping. Further, since only the cross-sectional shape of the internal gas supply pipe is specified, the hollow portion of the internal gas supply pipe can be effectively used as a reaction gas flow path without waste. Accordingly, the reaction gas can be more efficiently and uniformly ejected into the gas manifold.

  Furthermore, the thermal deformation preventing means can include a support member fixed to the wall surface of the gas manifold and supporting the internal gas supply pipe. The thermal deformation preventing means having this configuration can directly support any position in the axial direction of the internal gas supply pipe by the support member, and thus more reliably prevent thermal deformation of the internal gas supply pipe. be able to.

  Moreover, in this structure, the said supporting member can support the said internal gas supply piping so that a thermal expansion of the said internal gas supply piping is permitted. That is, since the internal gas supply pipe is not fixed to the support member, even if the internal gas supply pipe becomes hot and thermally expands, stress is applied to the internal gas supply pipe from the support member. There is almost no. Therefore, it is possible to more reliably prevent the internal gas supply pipe from being thermally deformed.

  In the fuel cell according to the present invention, the reaction gas is supplied from one end side of the internal gas supply pipe into the internal gas supply pipe, and the thermal deformation prevention means includes the internal gas supply pipe. The other end may be fixed to the wall surface of the gas manifold. With this configuration, one end side of the internal gas supply pipe is connected to a reaction gas supply pipe for supplying the reaction gas to the internal gas supply pipe, and the other end side is a wall surface of the gas manifold. Therefore, the other end side of the internal gas supply pipe can be prevented from being inclined downward due to thermal deformation. Therefore, it is possible to more reliably prevent the internal gas supply pipe from being thermally deformed.

  According to the present invention, the reaction gas can be made to reach evenly throughout the gas manifold, and the reaction gas can be evenly supplied to all the fuel cells, so that power generation can be performed efficiently. In addition, it is possible to provide a fuel cell with a long lifetime and high reliability.

FIG. 1 is an overall configuration diagram showing a fuel cell system including a fuel cell according to an embodiment of the present invention. FIG. 2 is a front sectional view showing the fuel cell module of the fuel cell shown in FIG. 3 is a cross-sectional view taken along the line III-III shown in FIG. 4 is a partial cross-sectional view showing a fuel cell unit which is a component of the fuel cell shown in FIG. FIG. 5 is a perspective view showing a fuel cell stack composed of a plurality of fuel cell units shown in FIG. 6 is a perspective view showing a gas manifold which is a component of the fuel cell shown in FIG. FIG. 7 is a diagram schematically showing the vicinity of an internal gas supply pipe which is a component of the fuel cell module shown in FIG. FIG. 8 is a cross-sectional view of an internal gas supply pipe that is a component of a fuel cell module according to another embodiment of the present invention. FIG. 9 is a diagram schematically showing a state in which the internal gas supply pipe shown in FIG. 8 is arranged in the gas manifold. FIG. 10 is a cross-sectional view of an internal gas supply pipe that is a component of a fuel cell module according to another embodiment of the present invention. FIG. 11 is a diagram schematically showing the vicinity of an internal gas supply pipe that is a component of a fuel cell module according to another embodiment of the present invention. 12 is a cross-sectional view taken along the line XII-XII shown in FIG.

  Next, a fuel cell according to an embodiment of the present invention will be described with reference to the drawings. In addition, embodiment described below is the illustration for demonstrating this invention, and this invention is not limited only to these embodiment. Therefore, the present invention can be implemented in various forms without departing from the gist thereof.

  1 is an overall configuration diagram showing a fuel cell system including a fuel cell according to an embodiment of the present invention, FIG. 2 is a front sectional view showing a fuel cell module of the fuel cell shown in FIG. 1, and FIG. FIG. 4 is a partial cross-sectional view showing a fuel cell unit which is a component of the fuel cell shown in FIG. 2, and FIG. 5 is a plurality of fuel cells shown in FIG. FIG. 6 is a perspective view showing a gas manifold which is a component of the fuel cell shown in FIG. 2, and FIG. 7 is a component of the fuel cell module shown in FIG. It is a figure which shows typically internal gas supply piping vicinity which is. In the drawings, for easy understanding, the thickness, size, enlargement / reduction ratio, etc. of each member are not matched with the actual ones.

  The fuel cell system FCS shown in FIG. 1 includes a fuel cell 1 and an auxiliary unit 4.

  The fuel cell 1 includes a fuel cell module 2, a hot water production apparatus 50 connected to the fuel cell module 2 and supplied with exhaust gas discharged from the fuel cell module 2, and a hot water production apparatus connected to the hot water production apparatus 50. A water supply source 24 for supplying tap water to 50, a control box 52 disposed in the fuel cell module 2 for controlling the supply amount of fuel gas supplied to the fuel cell module 2, and the fuel cell module 2 And an inverter 54 that is a power extraction unit (power conversion unit) for supplying the power generated by the fuel cell module 2 to the outside. In the hot water production apparatus 50, the tap water supplied from the water supply source 24 becomes hot water due to the heat of the exhaust gas, and is supplied to a hot water storage tank of an external water heater (not shown).

  The auxiliary unit 4 includes a pure water tank 26 that stores water from a water supply source 24 such as tap water and uses a filter as pure water, and a water flow rate adjustment unit that adjusts the flow rate of water supplied from the pure water tank 26. 28, a fuel supply source 30 for supplying a fuel gas (reformed gas) such as city gas, a gas shut-off valve 32 for shutting off the fuel gas supplied from the fuel supply source 30, and removing sulfur from the fuel gas A desulfurizer 36, a fuel flow rate adjustment unit 38 that adjusts the flow rate of the fuel gas, an air supply source 40 that supplies air as an oxidant, and an electromagnetic that blocks air supplied from the air supply source 40. The valve 42, the reforming air flow rate adjusting unit 44 and the power generation air flow rate adjusting unit 45 for adjusting the flow rate of the air, and the fuel gas supplied from the fuel flow rate adjusting unit 38 and the reforming air flow rate adjustment And a mixing unit 46 for mixing the air supplied reforming the knit 44.

  In the fuel cell system according to the present embodiment, the reforming air supplied to the reformer 20 and the power generation air supplied to the power generation chamber 10 are heated to efficiently raise the temperature at startup. No heating means such as a heater or heating means for separately heating the reformer 20 is provided.

  Next, the internal structure of the fuel cell module 2 will be described. As shown in FIGS. 1 to 3, the fuel cell module 2 includes a housing 6, and the inside of the housing 6 is a sealed space 8. A fuel cell assembly 12 that performs a power generation reaction with a fuel gas (reformed gas) and an oxidizing gas (air) is disposed in a power generation chamber 10 that is a lower portion of the sealed space 8. In addition, a combustion chamber 18 is formed above the power generation chamber 10 in the sealed space 8. In this combustion chamber 18, the remaining fuel gas that has not been used for the power generation reaction and the remaining air burn, and exhaust gas is discharged. It is designed to generate. A reformer 20 for reforming the fuel gas (reformed gas) is disposed above the combustion chamber 18, and reaches a temperature at which the reformer 20 can undergo a reforming reaction by the combustion heat of the residual gas. So that it is heated. Further, an air heat exchanger 22 for receiving combustion heat and heating air is disposed above the reformer 20. A gas manifold 66 is formed below the power generation chamber 10 in the sealed space 8.

  The fuel cell assembly 12 includes ten fuel cell stacks 14. As shown in FIG. 5, the fuel cell stack 14 includes 16 fuel cell units 16. With this configuration, the fuel cell assembly 12 includes 160 fuel cell units 16. It will be. Further, the lower end side and the upper end side of the fuel cell unit 16 are supported by ceramic support plates 68 and 100, respectively. The support plates 68 and 100 are formed with through holes 68a and 100a through which inner electrode terminals 86 described later can pass.

  The fuel cell unit 16 includes a fuel cell 84 and inner electrode terminals 86 respectively connected to the ends of the fuel cell 84 in the vertical direction. The fuel cell 84 is a tubular structure extending in the vertical direction, and includes a cylindrical inner electrode layer 90 that forms a fuel gas flow path 88 therein, a cylindrical outer electrode layer 92, an inner electrode layer 90, and an outer side. An electrolyte layer 94 is provided between the electrode layer 92 and the electrode layer 92. The inner electrode layer 90 is a fuel electrode (anode electrode) through which fuel gas passes, and the outer electrode layer 92 is an air electrode (cathode electrode) in contact with air. The upper part 90 a of the inner electrode terminal 86 has an outer peripheral surface 90 b and an upper end surface 90 c exposed to the electrolyte layer 94 and the outer electrode layer 92. The inner electrode terminal 86 is connected to the outer peripheral surface 90b through a conductive sealing material 96, and is electrically connected to the inner electrode layer 90 by making direct contact with the upper end surface 90c. In addition, a fuel gas passage 98 communicating with the fuel gas passage 88 of the inner electrode layer 90 is formed at the center of the inner electrode terminal 86.

  In addition, a current collector 102 and an external terminal 104 are attached to each fuel cell unit 16. The current collector 102 is integrally formed by a fuel electrode connection portion 102 a electrically connected to the inner electrode terminal 86 and an air electrode connection portion 102 b electrically connected to the entire outer peripheral surface of the outer electrode layer 92. Is formed. The external terminal 104 is connected to the external terminal 104 (not shown) of the fuel cell unit 16 at the end of the adjacent fuel cell stack 14 so that all 160 fuel cell units 16 are connected in series. It has become.

  The reformer 20 has a pure water introduction pipe 60 for introducing pure water to the upstream end side thereof, and a to-be-reformed gas introduction pipe 62 for introducing reformed fuel gas and reforming air. It is attached. Inside the reformer 20, an evaporator 20a and a reformer 20b are formed in order from the upstream side, and the reformer 20b is filled with a reforming catalyst. The fuel gas and air mixed with the steam (pure water) introduced into the reformer 20 are reformed by the reforming catalyst filled in the reformer 20. As the reforming catalyst, a catalyst obtained by imparting nickel to the alumina sphere surface or a catalyst obtained by imparting ruthenium to the alumina sphere surface is appropriately used. A fuel gas supply pipe 64 extending downward is connected to the downstream end side of the reformer 20.

  The air heat exchanger 22 includes an air aggregation chamber 70 on the upstream side and two air distribution chambers 72 on the downstream side. The air aggregation chamber 70 and the air distribution chamber 72 are separated by six air flow channel tubes 74. It is connected. Here, as shown in FIG. 3, three air flow path pipes 74 form a set (74a, 74b, 74c, 74d, 74e, 74f), and the air in the air collecting chamber 70 is in each set. It flows into each air distribution chamber 72 from the air flow path pipe 74. The air flowing through the six air flow path tubes 74 of the air heat exchanger 22 is preheated by the exhaust gas that burns and rises in the combustion chamber 18. An air introduction pipe 76 is connected to each of the air distribution chambers 72. The air introduction pipe 76 extends downward, and the lower end side communicates with the lower space of the power generation chamber 10, and the air that has been preheated in the power generation chamber 10. Is introduced.

  As shown in FIG. 6 in particular, the gas manifold 66 has a substantially rectangular parallelepiped shape with a bottom surface 67 having a rectangular shape, and a plate shape for supporting the fuel cell stack 14 is formed on the gas manifold 66. The support plate 68 is disposed. The support plate 68 is formed with a through hole 69 for supplying the fuel gas accommodated in the gas manifold 66 to the fuel gas flow path 88 of each fuel cell 84. The support plate 68 is disposed so as to face the bottom surface 67, whereby the bottom surface 67 serves as a facing wall disposed so as to face the support plate 68.

  Further, an internal gas supply pipe 63 for supplying fuel gas into the gas manifold 66 is disposed inside the gas manifold 66 with a predetermined distance from each of the bottom surface 67 and the support plate 68. The internal gas supply pipe 63 has a hollow cylindrical shape with a circular cross-sectional shape perpendicular to the axial direction, is horizontal along the fuel cell mounting surface of the support plate 68, and the bottom surface 67 of the gas manifold 66. It extends in the long side direction. As shown in FIG. 2, one end 63 </ b> A of the internal gas supply pipe 63 communicates with and is fixed to a fuel gas supply pipe 64 connected to the downstream end side of the reformer 20. The fuel gas is supplied from the reformer 20 through the fuel gas supply pipe 64. On the other hand, the other end 63B of the internal gas supply pipe 63 is fixed to the inner wall of the gas manifold 66 (the right inner wall in FIGS. 2 and 7), as shown in FIGS.

  Thus, since one end 63A of the internal gas supply pipe 63 is fixed to the fuel gas supply pipe 64 and the other end 63B is fixed to the inner wall of the gas manifold 66, the one end 63A and the other end 63B of the internal gas supply pipe 63 are heated. It is possible to prevent tilting downward due to the deformation, and it is possible to reliably prevent the internal gas supply pipe 63 from being thermally deformed. In the present embodiment, by fixing both ends of the internal gas supply pipe 63, the internal gas supply pipe 63 is prevented from being thermally deformed, and this configuration serves as a thermal deformation prevention means.

  Furthermore, the internal gas supply pipe 63 is formed with a plurality of injection holes 65 for vertically discharging the fuel gas (reformed fuel gas) supplied into the internal gas supply pipe 63 toward the bottom surface 67. Has been. As shown in FIGS. 2, 3, and 7, these ejection holes 65 are formed in a straight line on the lower surface of the internal gas supply pipe 63 at intervals from each other along the axial direction of the internal gas supply pipe 63. Has been.

  An exhaust gas chamber 78 is formed below the gas manifold 66, and an exhaust gas passage 80 extending in the vertical direction is formed inside the front surface 6a and the rear surface 6b, which are surfaces along the longitudinal direction of the housing 6. (See FIG. 3). The upper end side of the exhaust gas passage 80 communicates with the space in which the air heat exchanger 22 is disposed, and the lower end side communicates with the exhaust gas chamber 78. Further, an exhaust gas discharge pipe 82 is connected to substantially the center of the lower surface of the exhaust gas chamber 78, and the downstream end of the exhaust gas discharge pipe 82 is connected to the hot water production apparatus 50. Further, the combustion chamber 18 is provided with an ignition device 83 for starting combustion of fuel gas and air.

  In the start-up mode of the fuel cell system FCS in the present embodiment, combustion operation, partial oxidation reforming reaction (POX), first autothermal reforming reaction (ATR1), and second autothermal reforming reaction (ATR2) And the steam reforming reaction (SR) are sequentially switched and the reforming reaction proceeds.

The partial oxidation reforming reaction (POX) is a reforming reaction performed by supplying a reformed gas and air to the reformer 20, and the reaction shown in the chemical reaction formula (1) proceeds.
_{C m H n + xO 2 →} aCO 2 + bCO + cH 2 (1)
Since this partial oxidation reforming reaction (POX) is an exothermic reaction, its startability is high, and is a suitable reforming reaction at the beginning of starting the fuel cell system FCS. However, the partial oxidation reforming reaction (POX) is theoretically low in hydrogen yield and difficult to control the exothermic reaction. This is a preferred reforming reaction.

The steam reforming reaction (SR) is a reforming reaction performed by supplying the reformed gas and steam to the reformer 20, and the reaction shown in the chemical reaction formula (2) proceeds.
C _m H _n + xH ₂ O → aCO ₂ + bCO + cH ₂ (2)
The steam reforming reaction (SR) has the highest hydrogen yield and is a highly efficient reaction. However, since the steam reforming reaction (SR) is an endothermic reaction, it requires a heat source, and is a suitable reforming reaction at a stage where the temperature has risen to some extent from the beginning of the start of the fuel cell system FCS.

The autothermal reforming reaction (ATR) comprising the first autothermal reforming reaction (ATR1) and the second autothermal reforming reaction (ATR2) is a partial oxidation reforming reaction (POX) and a steam reforming reaction (SR). Is a reforming reaction that is performed by supplying the reformed gas, air, and water vapor to the reformer 20, and the reaction shown in the chemical reaction formula (3) proceeds. .
_{C m H n + xO 2 +} yH 2 O → aCO 2 + bCO + cH 2 (3)
Autothermal reforming reaction (ATR) is a combined use of partial oxidation reforming reaction (POX) and steam reforming reaction (SR) in hydrogen yield, and it is easy to balance reaction heat. POX) is a reforming reaction suitable as a reaction that connects the steam reforming reaction (SR). In the present embodiment, the first autothermal reforming reaction (ATR1) closer to the partial oxidation reforming reaction (POX) is performed by supplying a small amount of water, and the water is supplied to increase after the temperature rises. Then, the second autothermal reforming reaction (ATR2) closer to the steam reforming reaction (SR) is performed later.

  Next, the startup mode of the fuel cell system FCS will be described. First, the power generation air flow rate adjusting unit 45, the electromagnetic valve 42 and the mixing unit 46 are controlled so as to increase the reforming air, and air is supplied to the reformer 20. Further, as described above, power generation air is supplied to the power generation chamber 10 from the air introduction pipe 76. Further, the fuel flow rate adjusting unit 38 and the mixing unit 46 are controlled so as to increase the supply of the fuel gas, the reformed gas is supplied to the reformer 20, and the reformed gas sent to the reformer 20 is supplied. The reforming air is sent into each fuel cell unit 16 from each through hole 69 via the reformer 20, the fuel gas supply pipe 64, the internal gas supply pipe 63, and the gas manifold 66. The reformed gas and reforming air sent into each fuel cell unit 16 pass through the fuel gas channel 88 from the fuel gas channel 98 formed at the lower end of each fuel cell unit 16, The fuel gas flows out from the fuel gas passage 98 formed at the upper end. Thereafter, the gas to be reformed that has flowed out from the upper end of the fuel gas flow path 98 is ignited by the ignition device 83 to perform the combustion operation. As a result, the gas to be reformed is combusted in the combustion chamber 18, and the partial oxidation reforming reaction (POX) described above is generated.

  Thereafter, on the condition that the temperature of the reformer 20 is about 600 ° C. or higher and the temperature of the fuel cell assembly 12 exceeds about 250 ° C., the first autothermal reforming reaction (ATR1) described above is performed. And the transition to the second autothermal reforming reaction (ATR2) is performed on the condition that the temperature of the fuel cell assembly 12 exceeds about 400 ° C. At this time, the water flow rate adjusting unit 28, the fuel flow rate adjusting unit 38, and the reforming air flow rate adjusting unit 44 supply the reformer 20 with a gas in which the gas to be reformed, the reforming air, and the steam are previously mixed. . Next, the steam reforming reaction (SR) is performed on the condition that the temperature of the reformer 20 becomes 650 ° C. or higher and the temperature of the fuel cell assembly 12 exceeds about 600 ° C.

  As described above, the temperature in the power generation chamber 10 gradually increases by switching the reforming process in accordance with the progress of the combustion process from ignition. When the temperature of the power generation chamber 10 reaches a predetermined power generation temperature lower than the rated temperature (about 700 ° C.) at which the fuel cell module 2 is stably operated, the electric circuit including the fuel cell module 2 is closed. As a result, the fuel cell module 2 can start power generation, and current can flow through the circuit to supply power to the outside. Due to the power generation of the fuel cell 84, the fuel cell 84 itself also generates heat, and the temperature of the fuel cell 84 rises, so that the rated temperature for operating the fuel cell module 2, for example, 700 to 800 ° C. is reached.

  In this ignition to combustion process, the gas to be reformed and the reformed gas (fuel gas) supplied to the internal gas supply pipe 63 through the fuel gas supply pipe 64 are introduced into the gas manifold 66 from the respective ejection holes 65. Erupted. At this time, the internal gas supply pipe 63 is disposed inside the gas manifold 66, and the inside of the gas manifold 66 is hotter than the outside, so the gas supply pipe is disposed outside the gas manifold. Compared to the case, the heat radiation of the fuel gas can be reduced. Therefore, the heat radiation of the reaction gas when supplying the reaction gas to the gas manifold can be reduced. For this reason, high-temperature fuel gas can be supplied to the fuel battery cell 84 and the temperature rise of the fuel battery cell 84 can be promoted or the temperature drop can be suppressed, so that power generation can be performed efficiently. it can.

  Further, since the internal gas supply pipe 63 extends horizontally with the bottom surface 67 along the longitudinal direction of the gas manifold 66, the distance from the ejection hole 65 to the inner wall of the gas manifold 66 can be shortened, and the fuel gas Can reach every corner of the gas manifold 66. Further, since the internal gas supply pipe 63 and the bottom surface 67 are separated from each other, the fuel gas can be dispersed along the bottom surface 67 without being obstructed by the internal gas supply pipe 63, and the internal gas supply pipe 63 It can also be suppressed that the heat of the flowing fuel gas is taken by the bottom surface 67. Furthermore, as shown in FIG. 7, the fuel gas is ejected vertically toward the bottom surface 67 (that is, ejected with a velocity component toward the bottom surface 67), so the fuel ejected from the ejection hole 65. First, the gas is jetted downward toward the bottom surface 67 and then flows toward the support plate 68 while being dispersed. Accordingly, the fuel gas can be more evenly distributed throughout the gas manifold 66.

  The internal gas supply pipe 63 reaches about 500 ° C. to 600 ° C., but one end 63 A of the internal gas supply pipe 63 is fixed to the fuel gas supply pipe 64 and the other end 63 B is fixed to the inner wall of the gas manifold 66. Therefore, even if the internal gas supply pipe 63 tries to thermally deform downward due to its own weight, this thermal deformation is prevented and the shape of the internal gas supply pipe 63 is maintained. Therefore, since the fuel gas supplied to the inside of the internal gas supply pipe 63 can be uniformly ejected from the respective ejection holes 65, the fuel gas can be surely and evenly distributed throughout the gas manifold 66. it can. In addition, each ejection hole 65 is a relatively small hole, and by causing the fuel gas to be ejected from the ejection hole 65, an air current due to the fuel gas can be generated in the gas manifold 66 by the orifice effect. Can be efficiently dispersed throughout the gas manifold 66. Then, this fuel gas is equally supplied from the respective through holes 69 formed in the support plate 68 to the fuel gas flow paths 88 of the respective fuel cells 84. Accordingly, it is possible to suppress the occurrence of fuel depletion and heat generation temperature unevenness with respect to all the fuel battery cells 84, and the life of the fuel battery cells 84 can be improved.

  Further, when the operation of the fuel cell module 2 is stopped, the amount of fuel gas and water vapor supplied to the reformer 20 is reduced, and at the same time, the fuel cell module for generating air by the reforming air flow rate adjusting unit 44 The supply amount into 2 is increased, the fuel cell assembly 12 and the reformer 20 are cooled by air, and these temperatures are lowered. Thereafter, when the temperature of the power generation chamber decreases to a predetermined temperature, for example, 400 ° C., the supply of fuel gas and steam to the reformer 20 is stopped, and the steam reforming reaction (SR) of the reformer 20 is ended. . This supply of power generation air continues until the temperature of the reformer 20 decreases to a predetermined temperature, for example, 200 ° C., and when this temperature is reached, the power generation air flow from the power generation air flow rate adjustment unit 45 is reduced. Stop supplying.

  In the present embodiment, the case where one end 63A of the internal gas supply pipe 63 is fixed to the fuel gas supply pipe 64 and the other end 63B is fixed to the inner wall of the gas manifold 66 has been described as a means for preventing thermal deformation. Not limited to this, the heat deformation preventing means may be a rigidity enhancing means for enhancing the rigidity of the internal gas supply pipe 63 in the heat deformation direction. As this rigidity enhancing means, for example, as shown in FIG. 8, a rib 163 may be provided on the upper part in the vertical direction of the internal gas supply pipe 63 along the axial direction of the internal gas supply pipe 63. By arranging the rigidity reinforcing means in this way, even if the internal gas supply pipe 63 is subjected to thermal deformation downward due to its own weight, the heat of the internal gas supply pipe 63 is increased. Since the rigidity in the deformation direction (in this case, the vertical direction) is high, the internal gas supply pipe 63 can be prevented from being thermally deformed over the entire axial direction of the internal gas supply pipe 63. As shown in FIG. 9, in this configuration, the other end 63 </ b> B of the internal gas supply pipe 63 may not be fixed to the inner wall of the gas manifold 66, but may be fixed.

  Moreover, as said rigidity reinforcement | strengthening means, the structure where the cross-sectional shape perpendicular | vertical to the axial center direction of the internal gas supply piping 63 becomes a shape longer in the up-down direction than a horizontal direction can be mentioned, for example. Specifically, for example, as shown in FIG. 10, the outer shape of the cross section perpendicular to the axial direction of the internal gas supply pipe 63 is an ellipse (the minor axis of the ellipse is the horizontal direction, and the major axis is the vertical (vertical) direction). To do. In the case of this configuration, for example, the rigidity of the internal gas supply pipe 63 can be easily enhanced without providing the internal gas supply pipe 63 with a means for reinforcing the rigidity of the rib 163, for example. Further, the hollow portion of the internal gas supply pipe 63 can be effectively used as a fuel gas flow path without waste. Therefore, the fuel gas can be ejected more efficiently and uniformly into the gas manifold 66. Furthermore, in this configuration, the other end 63B of the internal gas supply pipe 63 may not be fixed to the inner wall of the gas manifold 66, but may be fixed.

  As shown in FIGS. 11 and 12, both ends of the thermal deformation preventing means are fixed to the wall surface of the gas manifold 66, and an internal gas supply pipe 63 is placed on the upper surface to place the internal gas supply pipe 63. It may be a support member 164 that supports. In particular, as shown in FIG. 12, these support members 164 have a circular arc surface 165 in which a portion on which the internal gas supply pipe 63 is placed protrudes downward, and the internal gas supply pipe 63 has an arc surface. It is directly supported without being fixed to 165. Therefore, even if the internal gas supply pipe 63 is thermally expanded, the internal gas supply pipe 63 is hardly subjected to stress from the support member 164, so that the internal gas supply pipe 63 is further prevented from being thermally deformed. can do. In the case of this configuration, any position in the axial direction of the internal gas supply pipe 63 can be directly supported by the support member 164. For this reason, for example, as shown in FIG. 11, when the other end 63B of the internal gas supply pipe 63 is not fixed (fixed in a cantilever state), and the other end 63B side may be deformed downward, By increasing the number of support members 164 provided on the other end 63B side as compared with the one end 63A side, thermal deformation of the internal gas supply pipe 63 can be further reliably prevented. Note that the position and number of the support members 164 can be determined as desired.

  Furthermore, in the present embodiment, the case where the fuel gas is ejected vertically toward the bottom surface 67 has been described. However, the present invention is not limited to this, and the fuel gas has a velocity parallel to the bottom surface 67 in addition to the velocity component toward the bottom surface 67. You may form the ejection hole 65 in the internal gas supply piping 63 so that it may eject with a component (namely, it may inject diagonally with respect to the bottom face 67). By forming the ejection holes 65 in this way, the flow in which the fuel gas ejected from each ejection hole 65 rises in the gas manifold 66 (flow toward the center along the support plate 68) collides with each other. Can be suppressed. Therefore, it is possible to suppress the fuel gas from staying on the internal gas supply pipe 63, so that the fuel gas can be more evenly distributed throughout the gas manifold 66.

  In the present embodiment, the case where the fuel cell 84 in which the inner electrode layer 90 is a fuel electrode (anode electrode) and the outer electrode layer 92 is an air electrode (cathode electrode) is provided has been described. Without limitation, a fuel battery cell in which the inner electrode layer 90 is an air electrode (cathode electrode) and the outer electrode layer 92 is a fuel electrode (anode electrode) may be disposed as desired. In this case, air (oxidant gas) may be supplied to the internal gas supply pipe 63.

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell, 2 ... Fuel cell module, 10 ... Power generation chamber, 20 ... Reformer, 63 ... Internal gas supply piping, 65 ... Injection hole, 66 ... Gas manifold, 67 ... Bottom surface, 68 ... Support plate, 69 ... Through-hole, 88 ... Fuel gas flow path, 163 ... Rib, 164 ... Support member, 165 ... Arc surface, FCS ... Fuel cell system

Claims (6)

A plurality of fuel cells each having a reaction gas flow path formed therein;
A gas manifold that contains the reaction gas inside,
Horizontally disposed above the gas manifold and supporting one end of the plurality of fuel cells in the direction of the reaction gas flow path, the reaction gas contained in the gas manifold is supplied to each reaction gas flow path. A support plate having a through hole to be supplied;
An internal gas supply that is disposed inside the gas manifold and has a plurality of ejection holes for ejecting the reaction gas, and supplies the reaction gas ejected from each ejection hole to the interior of the gas manifold. Piping,
Thermal deformation preventing means for preventing thermal deformation of the internal gas supply pipe;
With
The internal gas supply pipe has a fuel whose core is disposed along the fuel cell support surface of the support plate and spaced from the bottom surface of the gas manifold facing the support plate. battery.   2. The fuel cell according to claim 1, wherein the thermal deformation preventing unit includes a rigidity enhancing unit that is formed in the internal gas supply pipe and that reinforces the rigidity of the internal gas supply pipe with respect to a heat deformation direction.   3. The fuel cell according to claim 2, wherein the rigidity enhancing means has a structure in which a cross-sectional shape perpendicular to the axial direction of the internal gas supply pipe is longer in the vertical direction than in the horizontal direction.   2. The fuel cell according to claim 1, wherein the thermal deformation preventing means includes a support member fixed to a wall surface of the gas manifold and supporting the internal gas supply pipe.   The fuel cell according to claim 4, wherein the support member movably supports the internal gas supply pipe so as to allow thermal expansion of the internal gas supply pipe. The internal gas supply pipe is supplied with the reaction gas from one end thereof,
The fuel cell according to any one of claims 1 to 5, wherein the thermal deformation prevention means has a structure in which the other end of the internal gas supply pipe is fixed to a wall surface of the gas manifold.

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