JP6311867B2 - Fuel cell device - Google Patents

Description

  The present invention relates to a fuel cell device, and more particularly to a fuel cell device including an ignition device for igniting off-gas.

  A solid oxide fuel cell (hereinafter also referred to as “SOFC”) uses an oxide ion conductive solid electrolyte as an electrolyte, has electrodes attached to both sides thereof, and supplies fuel gas to one side. The fuel cell operates at a relatively high temperature by supplying an oxidant gas (air, oxygen, etc.) to the other side.

  Japanese Patent Laying-Open No. 2010-108698 (Patent Document 1) describes a solid oxide fuel cell device. In this fuel cell device, a fuel cell assembly comprising a plurality of fuel cell units is housed in a housing. This fuel cell assembly is composed of an array of a plurality of fuel cell stacks. In each fuel cell stack, the upper and lower ends of the plurality of fuel cell units are joined together by a support plate, so that the plurality of fuel cell units are integrated. The end of each fuel cell unit extends through the support plate in the vertical direction. The fuel gas introduced into the internal flow path from the lower end of the fuel cell unit during operation is used for the power generation reaction at the fuel electrode on the inner surface of the fuel cell unit. On the other hand, unreacted fuel gas (off-gas) that has not been used in the power generation reaction at the fuel electrode passes through the internal flow path, flows out from the upper end portion, and is guided to the combustion portion located above the fuel cell assembly.

  Further, in the apparatus described in Patent Document 1, the oxidant gas introduced from the lower side of the housing into the power generation chamber outside the fuel cell unit is generated at the oxidant gas electrode or the air electrode on the outer surface of the fuel cell unit. Used for. In addition, the oxidant gas that has not been used for the power generation reaction passes through a hole provided in the upper support plate and a gap between the adjacent upper support plates and is guided to the combustion unit.

  With such a configuration, in the apparatus described in Patent Document 1, off-gas and oxidant gas are mixed and burned in the combustion section. The fuel cell device includes an ignition device for igniting a mixed gas of off-gas and oxidant gas. The ignition device is an ignition source (for example, a heating element or a spark plug), and ignites offflowing off-gas in the presence of an oxidant gas at the upper end of one or more fuel cell units. Further, the ignited fuel cell unit becomes a heat source, and fire transfer occurs one after another to the adjacent fuel cell unit, and finally the transfer to all the fuel cell units of the fuel cell assembly is completed. Thereby, the combustion of off-gas is started in all the fuel cell units of the fuel cell assembly.

JP 2010-108698 A

  However, in the apparatus described in Patent Document 1, since the inflow path of the oxidant gas from the power generation chamber to the combustion part is narrowed by the support plate, the supply of the oxidant gas to the combustion part is limited, and good combustion stability is achieved. There was a problem that it could not be obtained. That is, the amount of oxidant gas supplied to the combustion section and the supply position are limited, it is difficult to stabilize the oxidant gas flow and mix off-gas and oxidant gas well. It was difficult to burn.

  On the other hand, when the support plate is removed, the supply of the oxidant gas from the power generation chamber to the combustion unit is not hindered by the support plate, so that the supply of oxidant gas to the combustion unit is improved. There is a problem in that the gas flow prevents rapid fire transfer from the ignited fuel cell unit.

  Accordingly, an object of the present invention is to provide a fuel cell device with improved ignitability to off-gas in the combustion section.

  In order to solve the above-described problems, the present invention is arranged in a housing in a fuel cell device including a fuel cell unit that generates electric power by a reaction between a fuel gas passing through an internal flow path and an external oxidant gas. A fuel cell assembly comprising an array of a plurality of the fuel cell units, an oxidant gas supply means for supplying an oxidant gas to the outside of the fuel cell unit from below the housing, and an upper part of the fuel cell assembly A combustion part that burns the fuel gas flowing through the internal flow path of the fuel cell unit unit and flowing out from the upper end of the fuel cell unit and the oxidant gas supplied by the oxidant gas supply means; And an igniter having an igniter for igniting a mixed gas of fuel gas and oxidant gas in the portion, and the oxidant gas only in the vicinity immediately below the igniter of the igniter An oxidant gas shielding plate for blocking the flow of the oxidant gas supplied from the supply means to the combustion unit is disposed, and the oxidant gas shielding plate has an oxidant gas shielding plate at the upper end of the plurality of fuel cell units. The fuel cell assembly is held in a penetrating state.

  In the present invention configured as described above, in the combustion section located above the fuel cell assembly, fuel gas (off gas) flowing through the internal flow path of each fuel cell unit and flowing out from the upper end, The oxidant gas supplied to the outside of the fuel cell unit and guided to the combustion part is combusted. In the combustion part, the mixed gas of off-gas and oxidant gas is ignited by an ignition device. In the present invention, an oxidant gas shielding plate that blocks the flow of the oxidant gas supplied to the combustion unit is disposed only near the ignition unit of the ignition device, and the oxidant gas shielding plate is The fuel cell unit assembly is held with the upper end portions of the plurality of fuel cell units penetrating therethrough.

  As described above, in the present invention, the flow of the oxidant gas supplied to the combustion unit is blocked or restricted by the oxidant gas shielding plate, but the oxidant gas shielding plate is locally disposed in the minimum necessary portion. Therefore, the blocking of the flow of the oxidant gas is limited. Rather, the flow of the oxidant gas passing around the oxidant gas shielding plate may be generated so as to circulate above the oxidant gas shielding plate. it can. As a result, the oxidant gas can be concentrated around the ignition part of the ignition device, and the oxidant gas flows out from the upper ends of the plurality of fuel cell units penetrating the oxidant gas shielding plate due to the concentrated air flow. The off gas to be concentrated can also be concentrated around the ignition part. Therefore, a fuel-rich mixed gas atmosphere is formed around the ignition part of the ignition device, and ignition is easy.

  Further, after ignition, the combustion flame extending from the upper end portion of each fuel cell unit is integrated and enlarged near the ignition portion by the concentrated air flow, and the ignition portion is exposed to a large combustion flame. That is, a combustion flame larger than the combustion flame caused by off-gas from a single fuel cell unit is formed. For this reason, the formed large combustion flame becomes a large heat source, and it is possible to cause the off-gas flowing out from the fuel cell unit other than the region where the oxidant gas shielding plate is provided one after another, that is, to ignite, The fuel cell unit can be ignited quickly. The enlarged combustion flame reaches the ignition device provided above the oxidant gas shielding plate. Thus, the ignitability by the ignition device can be improved by positively changing the airflow around the oxidant gas shielding plate.

  Further, in the present invention, during combustion, a sufficient amount of power generation air can be supplied above the fuel cell unit in a region where the oxidant gas shielding plate is not attached. Furthermore, since the shielding area of the oxidant gas shielding plate is limited even in the region where the oxidant gas shielding plate is attached, the oxidant gas can be supplied around the oxidant gas shielding plate. it can. Therefore, a sufficient amount of oxidant gas can be supplied above the oxidant gas shielding plate even if air current is disturbed, and combustion stability can be maintained.

Further, in the present invention, since the plurality of fuel cell units can be held by the oxidant gas shielding plate, the positions of the fuel cell units in the vicinity of the ignition unit of the ignition device are made uniform between different fuel cell devices. Can be aligned. Therefore, it is possible to prevent a time difference from occurring in the ignition process between different fuel cell devices.
Furthermore, in the present invention, since the oxidant gas shielding plate is arranged only at the upper end of some fuel cell units, the member cost is reduced as compared with the case where it is arranged so as to cover all the fuel cell units. can do.

In the present invention, preferably, the ignition part of the ignition device is disposed at a position shifted from the internal flow path of the fuel cell unit in a top view of the fuel cell device.
According to the present invention configured as described above, the ignition unit of the ignition device is disposed at a position that does not overlap the internal flow path of the fuel cell unit, so that it is adjacent to the internal flow paths of the plurality of fuel cell units. And an ignition part is arrange | positioned. As a result, off-gas from a plurality of adjacent fuel cell units can be concentrated and ignited in the ignition part, and ignition can be facilitated, and the formed combustion flame can be enlarged and quickly Can be easily transferred. For this reason, it is possible to prevent the off gas from staying in the combustion part or the like due to the ignition delay in the ignition process, and the occurrence of explosive combustion due to the stayed off gas.

In the present invention, preferably, the ignition unit of the ignition device is arranged at a position close to the internal flow paths of the plurality of adjacent fuel cell units in a top view of the fuel cell device.
According to the present invention configured as described above, it is possible to simultaneously ignite off-gas from the plurality of fuel battery cell units by the ignition unit, and it is possible to form a large combustion flame. Thereby, ignition with respect to all the fuel cell units can be completed quickly. For this reason, it is possible to prevent the off gas from staying in the combustion part or the like due to the ignition delay in the ignition process, and the occurrence of explosive combustion due to the stayed off gas.

In the present invention, preferably, each of the plurality of fuel cell units extends in the vertical direction and is disposed along the vertical direction and the horizontal direction in a top view of the fuel cell device. a substantially square in a top view of the battery device, and through the upper end of the four fuel cell units arranged in two rows and two columns along the longitudinal direction and the transverse direction in top view is transmural, igniter, probe-like The ignition portion extends at least to the approximate center of the oxidant gas shielding plate.
According to the present invention thus configured, the size of the oxidant gas shielding plate can be made to correspond to the four fuel cell units, and the shielding area of the oxidant gas can be reduced. Thereby, the oxidant gas supply to the off gas above the oxidant gas shielding plate can be stabilized during combustion. In addition, the ease of ignition is improved by concentrating the fuel gas flowing out from the four fuel cell units in the presence of the oxidant gas that is stably supplied, and further the fire to other fuel cell units is improved. Transferability can be improved.

In the present invention, a ceramic heater may be used as the ignition device. By using a ceramic heater as the ignition device, it is possible to ignite without generating noise in peripheral electronic devices and the like. Moreover, since the ignition part is ceramic, the ceramic heater can ensure durability without being oxidized at a high temperature.
In the present invention, a spark plug may be used as the ignition device. By using a spark plug as the ignition device, ignition can be reliably performed with a small amount of electric power.

  According to the fuel cell device of the present invention, it is possible to improve the ignitability of off-gas in the combustion section.

1 is an overall configuration diagram showing a solid oxide fuel cell system according to an embodiment of the present invention. 1 is a front sectional view showing a fuel cell module of a solid oxide fuel cell system according to an embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. It is a fragmentary sectional view showing a fuel cell unit of a solid oxide fuel cell system by one embodiment of the present invention. 1 is a perspective view showing a fuel cell stack of a solid oxide fuel cell system according to an embodiment of the present invention. 1 is a perspective view of a solid oxide fuel cell system according to an embodiment of the present invention with a housing, a heat insulating material, and the like removed from a fuel cell module. FIG. 7 is a top view of FIG. 6. 1 is a block diagram illustrating a solid oxide fuel cell system according to an embodiment of the present invention. It is a time chart which shows an example of each supply_amount | feed_rate of fuel etc. in the starting process of the solid oxide fuel cell system by one Embodiment of this invention, and the temperature of each part. It is explanatory drawing of the ignition rod and shielding board of the ignition device of the solid oxide fuel cell system by one Embodiment of this invention. It is explanatory drawing of the operation | movement in the ignition process of the solid oxide fuel cell system by one Embodiment of this invention.

Next, a solid oxide fuel cell system (SOFC) according to an embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is an overall configuration diagram showing a solid oxide fuel cell system (SOFC) according to an embodiment of the present invention. As shown in FIG. 1, a solid oxide fuel cell system (SOFC) 1 according to an embodiment of the present invention includes a fuel cell module 2 and an auxiliary unit 4.

  The fuel cell module 2 includes a housing 6, and a metal case 8 is built in the housing 6 via a heat insulating material 7. A fuel cell assembly 12 that performs a power generation reaction with fuel and oxidant gas (air) is disposed in a power generation chamber 10 that is a lower portion of the case 8 that is a sealed space. The fuel cell assembly 12 includes nine fuel cell stacks 14 (see FIG. 5). The fuel cell stack 14 includes 16 fuel cell unit 16 (see FIG. 4). Yes. Thus, the fuel cell assembly 12 has 144 fuel cell units 16, and all of these fuel cell units 16 are connected in series.

A combustion chamber 18 that is a combustion section is formed above the above-described power generation chamber 10 of the case 8 of the fuel cell module 2. In this combustion chamber 18, the remaining fuel and the remaining oxidant that have not been used for the power generation reaction. (Air) is combusted to generate exhaust gas. Further, the case 8 is covered with a heat insulating material 7 to suppress the heat inside the fuel cell module 2 from being diffused to the outside air.
Further, a reformer 20 for reforming the fuel is disposed above the combustion chamber 18, and the reformer 20 is heated to a temperature at which a reforming reaction can be performed by the combustion heat of the residual gas. Yes. Further, an air heat exchanger 22, which is a heat exchanger for heating the power generation air with the remaining combustion gas and preheating the power generation air, is disposed above the reformer 20.

  Next, the auxiliary unit 4 stores pure water tank 26 that stores water condensed from moisture contained in the exhaust from the fuel cell module 2 and makes it pure water with a filter, and water supplied from the water storage tank. Is provided with a water flow rate adjusting unit 28 (such as a “water pump” driven by a motor). In addition, the auxiliary unit 4 adjusts the flow rate of the fuel gas, the gas shutoff valve 32 for shutting off the fuel supplied from the fuel supply source 30 such as city gas, the desulfurizer 36 for removing sulfur from the fuel gas, A fuel flow adjustment unit 38 (such as a “fuel pump” driven by a motor) and a valve 39 that shuts off fuel gas flowing out from the fuel flow adjustment unit 38 when power is lost. Further, the auxiliary unit 4 includes an electromagnetic valve 42 that shuts off air that is an oxidant gas supplied from an air supply source 40, a reforming air flow rate adjusting unit 44 that adjusts the flow rate of air, and a power generation air flow rate adjustment. A unit 45 (such as an “air blower” driven by a motor), a first heater 46 for heating the reforming air supplied to the reformer 20, and a first heater for heating the power generating air supplied to the power generation chamber 2 heaters 48. The first heater 46 and the second heater 48 are provided in order to efficiently raise the temperature at startup, but may be omitted.

Next, a hot water production apparatus 50 to which exhaust gas is supplied is connected to the fuel cell module 2. The hot water production apparatus 50 is supplied with tap water from the water supply source 24, and the tap water is heated by the heat of the exhaust gas and supplied to a hot water storage tank of an external hot water heater (not shown).
The fuel cell module 2 is provided with a control box 52 for controlling the amount of fuel gas supplied and the like.
Furthermore, the fuel cell module 2 is connected to an inverter 54 that is a power extraction unit (power conversion unit) for supplying the power generated by the fuel cell module to the outside.

Next, the internal structure of the fuel cell module of the solid oxide fuel cell system (SOFC) according to the embodiment of the present invention will be described with reference to FIGS. 2 is a side sectional view showing a fuel cell module of a solid oxide fuel cell system (SOFC) according to an embodiment of the present invention, and FIG. 3 is a sectional view taken along line III-III in FIG. is there.
As shown in FIGS. 2 and 3, the case 8 in the housing 6 of the fuel cell module 2 has a fuel cell assembly 12, a reformer 20, and an air heat exchanger in order from the bottom as described above. 22 is arranged.

The reformer 20 is provided with a reformer introduction pipe 62 for introducing pure water, fuel gas to be reformed, and reforming air on the end side surface on the upstream end side.
The reformer introduction pipe 62 is a circular pipe extending from the side wall surface at one end of the reformer 20, is bent by 90 ° and extends in a substantially vertical direction, and penetrates the upper end surface of the case 8. The reformer introduction pipe 62 functions as a water introduction pipe for introducing water into the reformer 20. Further, a T-shaped tube 62a is connected to the upper end of the reformer introduction tube 62, and fuel gas and pure water are supplied to both ends of the T-shaped tube 62a extending in a substantially horizontal direction. Pipes for connecting are connected to each other. The water supply pipe 63a extends obliquely upward from one side end of the T-shaped pipe 62a. The fuel gas supply pipe 63b extends in the horizontal direction from the other side end of the T-shaped pipe 62a, then bends in a U shape, and extends substantially horizontally in the same direction as the water supply pipe 63a.

  On the other hand, an evaporation unit 20a, a mixing unit 20b, and a reforming unit 20c are formed in the reformer 20 sequentially from the upstream side, and the reforming unit 20c 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 is connected to the downstream end side of the reformer 20, and the fuel gas supply pipe 64 extends downward and further in an manifold 66 formed below the fuel cell assembly 12. It extends horizontally. A plurality of fuel supply holes 64 b are formed in the lower surface of the horizontal portion 64 a of the fuel gas supply pipe 64, and the reformed fuel gas is supplied into the manifold 66 from the fuel supply holes 64 b. Further, in the middle of the vertical portion of the fuel gas supply pipe 64, a pressure fluctuation suppressing flow path resistance portion 64c having a narrow flow path is provided, and the flow path resistance of the fuel gas supply flow path is adjusted.

  A lower support plate 68 having a through hole for supporting the fuel cell stack 14 described above is attached above the manifold 66, and the fuel gas in the manifold 66 flows into the fuel cell unit 16. Supplied.

On the other hand, an air heat exchanger 22 is provided above the reformer 20.
Further, as shown in FIG. 2, an ignition device 83 for starting combustion of fuel gas and air is provided in the combustion chamber 18.

Next, the fuel cell unit 16 will be described with reference to FIG. FIG. 4 is a partial cross-sectional view showing a fuel cell unit of a solid oxide fuel cell system (SOFC) according to an embodiment of the present invention.
As shown in FIG. 4, the fuel cell unit 16 includes a fuel cell 84 and inner electrode terminals 86 that are caps respectively connected to both ends of the fuel cell 84.
The fuel battery cell 84 is a tubular structure extending in the vertical direction, and includes a cylindrical inner electrode layer 90 that forms an internal flow path 88 through which fuel gas flows, a cylindrical outer electrode layer 92, and an inner electrode layer. 90 and an electrolyte layer 94 between the outer electrode layer 92 and the outer electrode layer 92. The inner electrode layer 90 is a fuel electrode through which fuel gas passes and becomes a (−) electrode, while the outer electrode layer 92 is an air electrode in contact with air and becomes a (+) electrode.

  Since the inner electrode terminal 86 attached to the upper end side and the lower end side of the fuel cell 84 has the same structure, the inner electrode terminal 86 attached to the upper end side will be specifically described here. The upper portion 90 a of the inner electrode layer 90 includes 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 of the inner electrode layer 90 through a conductive sealing material 96, and is further in direct contact with the upper end surface 90c of the inner electrode layer 90, thereby Electrically connected. In the center portion of the inner electrode terminal 86, an internal channel thin tube 98 communicating with the internal channel 88 of the inner electrode layer 90 is formed.

  The internal flow passage narrow tube 98 is an elongated thin tube provided so as to extend in the axial direction of the fuel cell 84 from the center of the inner electrode terminal 86. Therefore, a predetermined pressure loss occurs in the flow of the fuel gas flowing from the manifold 66 (FIG. 2) into the internal flow path 88 through the internal flow path narrow tube 98 of the lower inner electrode terminal 86. Accordingly, the internal channel capillary 98 of the lower inner electrode terminal 86 functions as an inflow channel resistance part, and the channel resistance is set to a predetermined value. A predetermined pressure loss also occurs in the flow of the fuel gas flowing out from the internal flow path 88 to the combustion chamber 18 (FIG. 2) through the internal flow path narrow tube 98 of the upper inner electrode terminal 86. Therefore, the internal channel narrow tube 98 of the upper inner electrode terminal 86 acts as an outflow side channel resistance, and the channel resistance is set to a predetermined value.

  The inner electrode layer 90 includes, for example, a mixture of Ni and zirconia doped with at least one selected from rare earth elements such as Ca, Y, and Sc, and Ni and ceria doped with at least one selected from rare earth elements. The mixture is formed of at least one of Ni and a mixture of lanthanum garade doped with at least one selected from Sr, Mg, Co, Fe, and Cu.

  The electrolyte layer 94 includes, for example, zirconia doped with at least one selected from rare earth elements such as Y and Sc, ceria doped with at least one selected from rare earth elements, lanthanum gallate doped with at least one selected from Sr and Mg, Formed from at least one of the following.

  The outer electrode layer 92 includes, for example, lanthanum manganite doped with at least one selected from Sr and Ca, lanthanum ferrite doped with at least one selected from Sr, Co, Ni and Cu, Sr, Fe, Ni and Cu. It is formed from at least one of lanthanum cobaltite doped with at least one selected from the group consisting of silver and silver.

Next, the fuel cell stack 14 will be described with reference to FIG. FIG. 5 is a perspective view showing a fuel cell stack of a solid oxide fuel cell system (SOFC) according to an embodiment of the present invention.
As shown in FIG. 5, the fuel cell stack 14 includes 16 fuel cell units 16, and these fuel cell units 16 are arranged in two rows of 8 each.
Each fuel cell unit 16 has a lower end supported by a rectangular lower support plate 68 (FIG. 2) made of ceramic. These lower support plates 68 are formed with through holes through which the inner electrode terminals 86 can pass.

  Furthermore, a current collector 102 and an external terminal 104 are attached to the fuel cell unit 16. The current collector 102 includes a fuel electrode connection portion 102a that is electrically connected to an inner electrode terminal 86 attached to the inner electrode layer 90 that is a fuel electrode, and an outer peripheral surface of the outer electrode layer 92 that is an air electrode. It is integrally formed so as to connect the air electrode connecting portion 102b that is electrically connected. In addition, a silver thin film is formed on the entire outer surface of the outer electrode layer 92 (air electrode) of each fuel cell unit 16 as an electrode on the air electrode side. When the air electrode connecting portion 102b contacts the surface of the thin film, the current collector 102 is electrically connected to the entire air electrode.

  Furthermore, two external terminals 104 are connected to the air electrode 86 of the fuel cell unit 16 located at the end of the fuel cell stack 14 (the far left side in FIG. 5). These external terminals 104 are connected to the inner electrode terminal 86 of the fuel cell unit 16 at the end of the adjacent fuel cell stack 14, and as described above, all 144 fuel cell units 16 are connected in series. It has come to be.

  The fuel cell stack 14 shown in FIG. 5 is arranged at the center of the nine fuel cell stacks 14 (see FIG. 2). The fuel cell stack 14 located in the center has a substantially square outer shape on the upper end side of the four fuel cell units 16 arranged in the second and third from the left end of each row in FIG. A shielding plate 100 is attached. The shielding plate 100 is a flat plate made of ceramic (for example, MgO) similar to the lower support plate 68. The shielding plate 100 is held with respect to the fuel cell unit 16 in a state where the internal flow path narrow tubes 98 of the four fuel cell units 16 are inserted into the through holes provided in the shielding plate 100.

Next, the ignition device 83 in the present embodiment will be described with reference to FIGS. 6 is a perspective view of the fuel cell module 2 with the housing 6, the heat insulating material 7 and the like removed, and FIG. 7 is a top view of FIG.
The ignition device 83 of the present embodiment is an electric ceramic heater, and an ignition rod 83b that is a heating source extending from the main body portion 83a generates heat when a power source is applied. In the ignition device 83, an ignition rod 83b passes through the case 8 and the heat insulating material 7, and is inserted into the combustion chamber 18 (see FIG. 2) from the side surface of the housing 6.

As shown in FIGS. 6 and 7, the ignition rod 83 b has two rows along the row direction of the fuel cell stack 14 composed of the two rows of fuel cell units 16 located in the center in the combustion chamber 18. The tip portion where the temperature is highest reaches the upper portion of the central portion of the shielding plate 100.
In this embodiment, a ceramic heater is used as the ignition device 83. However, the present invention is not limited to this, and an ignition plug that generates an electric spark may be used. In this case, the spark plug may be arranged so that the ignition part that generates an electric spark as an ignition source is positioned above the shielding plate 100.

Next, the sensors and the like attached to the solid oxide fuel cell system (SOFC) according to the present embodiment will be described with reference to FIG. FIG. 8 is a block diagram illustrating a solid oxide fuel cell system (SOFC) according to an embodiment of the present invention.
As shown in FIG. 8, the solid oxide fuel cell system 1 includes a control unit 110, and the control unit 110 includes operation buttons such as “ON” and “OFF” for operation by the user. The operation device 112, a display device 114 for displaying various data such as a power generation output value (wattage), and a notification device 116 for issuing a warning (warning) in an abnormal state are connected. In addition, the control unit 110 incorporates a microprocessor, a memory, and a program (not shown) for operating these components, and thereby, based on input signals from the respective sensors, the auxiliary unit 4, The inverter 54 and the like are controlled. The notification device 116 may be connected to a remote management center and notify the management center of an abnormal state.

Next, signals from various sensors described below are input to the control unit 110.
First, the combustible gas detection sensor 120 is for detecting a gas leak, and is attached to the fuel cell module 2 and the auxiliary unit 4.
The CO detection sensor 122 detects whether or not CO in the exhaust gas originally discharged to the outside through the exhaust gas passage 80 or the like leaks to an external housing (not shown) that covers the fuel cell module 2 and the auxiliary unit 4. Is to do.
The hot water storage state detection sensor 124 is for detecting the temperature and amount of hot water in a water heater (not shown).

The power state detection sensor 126 is for detecting the output current and voltage of the fuel cell module 2.
The power generation air flow rate detection sensor 128 is for detecting the flow rate of power generation air supplied to the power generation chamber 10.
The reforming air flow sensor 130 is for detecting the flow rate of the reforming air supplied to the reformer 20.
The fuel flow sensor 132 is for detecting the flow rate of the fuel gas supplied to the reformer 20.

The water flow rate sensor 134 is for detecting the flow rate of pure water supplied to the reformer 20.
The water level sensor 136 is for detecting the water level of the pure water tank 26.
The pressure sensor 138 is for detecting the pressure on the upstream side outside the reformer 20.
The exhaust temperature sensor 140 is for detecting the temperature of the exhaust gas flowing into the hot water production apparatus 50.

As shown in FIG. 3, the power generation chamber temperature sensor 142 is provided on the front side and the back side in the vicinity of the fuel cell assembly 12, and detects the temperature in the vicinity of the fuel cell stack 14 to thereby detect the fuel cell stack. 14 (ie, the fuel cell 84 itself) is estimated.
The combustion chamber temperature sensor 144 is for detecting the temperature of the combustion chamber 18.
The exhaust gas chamber temperature sensor 146 is for detecting the temperature of the exhaust gas in the exhaust gas chamber 78.
The reformer temperature sensor 148 is for detecting the temperature of the reformer 20, and calculates the temperature of the reformer 20 from the inlet temperature and the outlet temperature of the reformer 20.
The outside air temperature sensor 150 is for detecting the temperature of the outside air when the solid oxide fuel cell system (SOFC) is disposed outdoors. Further, a sensor for measuring the humidity or the like of the outside air may be provided.

  Signals from these sensors are sent to the control unit 110, and the control unit 110, based on data based on these signals, the water flow rate adjustment unit 28, the fuel flow rate adjustment unit 38, the reforming air flow rate adjustment unit 44, A control signal is sent to the power generation air flow rate adjusting unit 45 to control each flow rate in these units.

Next, the flow of fuel, power generation air, and exhaust gas during the power generation operation of the solid oxide fuel cell system 1 will be described.
First, the fuel is introduced into the evaporation section 20a of the reformer 20 through the fuel gas supply pipe 63b, the T-shaped pipe 62a, and the reformer introduction pipe 62, and the pure water is supplied to the water supply pipe 63a, It is introduced into the evaporator 20a through the T-shaped tube 62a and the reformer introducing tube 62. Accordingly, the supplied fuel and water are merged in the T-shaped tube 62 a and introduced into the evaporation unit 20 a through the reformer introduction tube 62. During the power generation operation, since the evaporation unit 20a is heated to a high temperature, the pure water introduced into the evaporation unit 20a is evaporated relatively quickly to become water vapor. The evaporated water vapor and fuel are mixed in the mixing unit 20 b and flow into the reforming unit 20 c of the reformer 20. The fuel introduced into the reforming unit 20c together with the steam is steam reformed here and reformed into a fuel gas rich in hydrogen. The fuel reformed in the reforming unit 20c goes down through the fuel gas supply pipe 64 and flows into the manifold 66 which is a dispersion chamber.

  The manifold 66 is a rectangular parallelepiped space having a relatively large volume, which is disposed on the lower side of the fuel cell stack 14, and a plurality of holes provided on the upper surface thereof constitute each fuel cell constituting the fuel cell stack 14. It communicates with the inside of the unit 16. The fuel introduced into the manifold 66 flows out from the upper end of the fuel cell unit 16 through the many holes provided on the upper surface thereof, through the fuel electrode side of the fuel cell unit 16, that is, through the inside of the fuel cell unit 16. . Further, when hydrogen gas as a fuel passes through the inside of the fuel cell unit 16, it reacts with oxygen in the air passing outside the fuel cell unit 16 as an air electrode (oxidant gas electrode) to generate a charge. Is done. The remaining fuel that is not used for power generation flows out from the upper end of each fuel cell unit 16 and is combusted in a combustion chamber 18 provided above the fuel cell stack 14.

  On the other hand, the power generation air that is the oxidant gas is sent into the fuel cell module 2 through the power generation air introduction pipe 74 by the power generation air flow rate adjustment unit 45 that is a power generation oxidant gas supply device. The air sent into the fuel cell module 2 is introduced into the power generation air passage 72 of the air heat exchanger 22 via the power generation air introduction pipe 74 and preheated. The preheated air flows out to each communication channel 76 via each outlet port 76a (FIG. 3). The power generation air flowing into each communication channel 76 flows downward through the power generation air supply passages 77 provided on both side surfaces of the fuel cell module 2, and the fuel cell stack 14 from a number of outlets 77a. Toward the power generation chamber 10.

  The air injected into the power generation chamber 10 comes into contact with the outer surface of each fuel cell unit 16 on the air electrode side (oxidant gas electrode side) of the fuel cell stack 14, and a part of oxygen in the air is in contact with it. Used for power generation. Moreover, the air injected to the lower part of the power generation chamber 10 through the blower outlet 77a rises in the power generation chamber 10 while being used for power generation. The air rising in the power generation chamber 10 burns the fuel flowing out from the upper end of each fuel cell unit 16. The combustion heat generated by this combustion heats the evaporation section 20a, the mixing section 20b, and the reforming section 20c of the reformer 20 disposed above the fuel cell stack 14. The combustion gas generated by burning the fuel heats the upper reformer 20 and then flows into the upper side of the rectifying plate 21 through the opening 21 a above the reformer 20. The combustion gas that has flowed into the upper side of the rectifying plate 21 is guided to the communication opening 8 a that is the inlet of the air heat exchanger 22 through the exhaust passage 21 b formed by the rectifying plate 21. The combustion gas that has flowed into the air heat exchanger 22 from the communication opening 8 a flows into the open end of each combustion gas pipe 70 and flows through the power generation air flow path 72 outside each combustion gas pipe 70. Are exchanged with each other and collected in an exhaust gas collecting chamber 78. The exhaust gas collected in the exhaust gas collection chamber 78 is discharged to the outside of the fuel cell module 2 through the exhaust gas discharge pipe 82. As a result, the evaporation of water in the evaporation unit 20a and the steam reforming reaction, which is an endothermic reaction in the reforming unit 20c, are promoted, and the power generation air in the air heat exchanger 22 is preheated.

Next, control in the starting process of the solid oxide fuel cell system 1 will be described with reference to FIG.
FIG. 9 is a time chart illustrating an example of each supply amount of fuel and the temperature of each part in the startup process. In addition, the scale of the vertical axis | shaft of FIG. 9 has shown temperature, and each supply amount of fuel etc. has shown those increase / decrease roughly.

In the start-up process shown in FIG. 9, the temperature of the fuel cell stack 14 at room temperature is raised to a temperature at which power generation is possible.
First, at time t0 in FIG. 9, supply of power generation air and reforming air is started. Specifically, the control unit 110 that is a controller sends a signal to the power generation air flow rate adjustment unit 45 that is a power generation oxidant gas supply device to operate it. As described above, the power generation air is introduced into the fuel cell module 2 through the power generation air introduction pipe 74 and flows into the power generation chamber 10 through the air heat exchanger 22 and the power generation air supply path 77. . In addition, the control unit 110 sends a signal to the reforming air flow rate adjustment unit 44 which is a reforming oxidant gas supply device to operate it. The reforming air introduced into the fuel cell module 2 flows into the interior of each fuel cell unit 16 through the reformer 20 and the manifold 66, and flows out from the upper end thereof. Note that at time t0, no reforming reaction occurs in the reformer 20 because fuel has not yet been supplied. In the present embodiment, the supply amount of power generation air started at time t0 in FIG. 9 is about 100 L / min, and the supply amount of reforming air is about 9.0 L / min.

  Next, fuel supply is started at time t1 after a predetermined time from time t0 in FIG. Specifically, the control unit 110 sends a signal to the fuel flow rate adjustment unit 38 which is a fuel supply device to operate it. In the present embodiment, the fuel supply amount started at time t1 is about 5.0 L / min. The fuel introduced into the fuel cell module 2 flows into the interior of each fuel cell unit 16 through the reformer 20 and the manifold 66, and flows out from the upper end thereof. At time t1, the reformer reaction is not generated in the reformer 20 because the temperature of the reformer is still low.

  Next, at time t2 when a predetermined time has elapsed from time t1 in FIG. 9, an ignition process for the supplied fuel is started. Specifically, in the ignition process, the control unit 110 sends a signal to an ignition device 83 (FIG. 2) that is an ignition means, and ignites the fuel flowing out from the upper end of each fuel cell unit 16. The ignition device 83 causes the ignition rod 83b to generate heat near the upper end of the fuel cell stack 14, and uses this as a heat source to ignite the fuel flowing out from the upper end of each fuel cell unit 16.

When ignition is completed at time t3 in FIG. 9, supply of reforming water is started. Specifically, the control unit 110 sends a signal to the water flow rate adjustment unit 28 (FIG. 8), which is a water supply device, to activate it. In the present embodiment, the supply amount of water started at time t3 is 2.0 cc / min. At time t3, the fuel supply amount is maintained at about 5.0 L / min. Further, the supply amounts of the power generation air and the reforming air are also maintained at the previous values. At this time t3, the ratio O ₂ / C of oxygen O ₂ in the reforming air and carbon C in the fuel becomes about 0.32.

  After being ignited at time t3 in FIG. 9, the supplied fuel flows out as off-gas from the upper end of each fuel cell unit 16, and is burned here. This combustion heat heats the reformer 20 disposed above the fuel cell stack 14. Here, an evaporating chamber heat insulator 23 is disposed above the reformer 20 (above the case 8), so that immediately after the start of fuel combustion, the temperature of the reformer 20 suddenly increases from room temperature. To rise. Since the outside air is introduced into the air heat exchanger 22 disposed on the heat insulating material 23 for the evaporation chamber, the air heat exchanger 22 has a low temperature, particularly immediately after the start of combustion, and serves as a cooling source. Cheap. In the present embodiment, the evaporation chamber heat insulating material 23 is disposed between the upper surface of the case 8 and the bottom surface of the air heat exchanger 22, so that the reformer 20 disposed in the upper portion of the case 8 The movement of heat to the air heat exchanger 22 is suppressed, and heat is easily trapped in the vicinity of the reformer 20 in the case 8. In addition, the space above the rectifying plate 21 above the evaporation unit 20a is configured as a gas retention space 21c (FIG. 2) in which the flow of combustion gas is slow, so that the vicinity of the evaporation unit 20a is double insulated. And the temperature rises more rapidly.

  As described above, the temperature of the evaporation unit 20a rapidly increases, so that water vapor can be generated in a short time after the start of off-gas combustion. In addition, since the reforming water is supplied to the evaporation unit 20a little by little, it is possible to heat the water to the boiling point with a slight amount of heat compared to the case where a large amount of water is stored in the evaporation unit 20a. The supply of water vapor can be started immediately. Furthermore, since water flows in immediately after the start of the operation of the water flow rate adjustment unit 28, it is possible to avoid an excessive increase in temperature of the evaporation unit 20a and a delay in supply of water vapor due to a delay in supply of water.

  When a certain amount of time elapses after the start of off-gas combustion, the temperature of the air heat exchanger 22 also rises due to the exhaust gas flowing from the combustion chamber 18 into the air heat exchanger 22. The evaporation chamber heat insulating material 23 that insulates between the reformer 20 and the air heat exchanger 22 is a heat insulating material provided inside the heat insulating material 7. Therefore, the heat insulating material 23 for the evaporation chamber does not suppress the dissipation of heat from the fuel cell module 2, but immediately increases the temperature of the reformer 20, particularly the evaporation section 20a immediately after the start of off-gas combustion. Let

In this way, at time t4 when the temperature of the reformer 20 rises, the fuel and the reforming air that have flowed into the reforming unit 20c through the evaporation unit 20a undergo the partial oxidation reforming reaction shown in the equation (1). Get up.
_{C m H n + xO 2 →} aCO 2 + bCO + cH 2 (1)
Since this partial oxidation reforming reaction is an exothermic reaction, when the partial oxidation reforming reaction occurs in the reforming portion 20c, the ambient temperature rapidly rises locally.

On the other hand, in the present embodiment, the supply of the reforming water is started from time t3 immediately after the ignition is confirmed, and the temperature of the evaporation unit 20a is rapidly increased. At time t4, water vapor has already been generated in the evaporation section 20a and supplied to the reforming section 20c. That is, after the off-gas is ignited, the supply of water is started a predetermined time before the temperature of the reforming unit 20c reaches the temperature at which the partial oxidation reforming reaction occurs, and reaches the temperature at which the partial oxidation reforming reaction occurs. At that time, a predetermined amount of water is stored in the evaporation unit 20a, and water vapor is generated. For this reason, when the temperature rapidly rises due to the occurrence of the partial oxidation reforming reaction, a steam reforming reaction occurs in which the steam for reforming supplied to the reforming unit 20c reacts with the fuel. This steam reforming reaction is an endothermic reaction shown in Formula (2), and occurs at a higher temperature than the partial oxidation reforming reaction.
C _m H _n + xH ₂ O → aCO ₂ + bCO + cH ₂ (2)

As described above, when the time t4 in FIG. 9 is reached, the partial oxidation reforming reaction occurs in the reforming unit 20c, and the steam reforming is caused by the temperature rise caused by the partial oxidation reforming reaction. Reaction will also occur at the same time. Therefore, the reforming reaction that occurs in the reforming unit 20c after time t4 is an autothermal reforming reaction (ATR) shown in Formula (3) in which the partial oxidation reforming reaction and the steam reforming reaction are mixed. That is, the ATR1 process is started at time t4.
_{C m H n + xO 2 +} yH 2 O → aCO 2 + bCO + cH 2 (3)

Thus, in the solid oxide fuel cell system 1 according to the embodiment of the present invention, water is supplied during the entire start-up process, and the partial oxidation reforming reaction (POX) does not occur alone. In the time chart shown in FIG. 9, the reformer temperature at time t4 is about 200.degree. The reformer temperature is lower than the temperature at which the partial oxidation reforming reaction occurs, but the temperature detected by the reformer temperature sensor 148 (FIG. 8) is the average temperature of the reforming unit 20c.
Actually, even at time t4, the reforming unit 20c partially reaches the temperature at which the partial oxidation reforming reaction occurs, and the steam reforming reaction is performed by the reaction heat of the generated partial oxidation reforming reaction. Is also triggered. Thus, in the present embodiment, after the ignition, the supply of water is started before the reforming unit 20c reaches the temperature at which the partial oxidation reforming occurs, and the partial oxidation reforming reaction is performed independently. Will not occur.

Next, when the temperature detected by the reformer temperature sensor 148 reaches about 500 ° C. or higher, the process proceeds from the ATR1 process to the ATR2 process at time t5 in FIG. At time t5, the water supply amount is changed from 2.0 cc / min to 3.0 cc / min. Further, the fuel supply amount, the reforming air supply amount, and the power generation air supply amount are maintained at the previous values. As a result, the steam / carbon ratio S / C in the ATR2 step is increased to 0.64, while the reforming air / carbon ratio O ₂ / C is maintained at 0.32. Thus, by maintaining the ratio of reforming air and carbon O ₂ / C constant, the ratio S / C of steam and carbon is increased, so that the amount of carbon that can be partially oxidized and reformed is not reduced. In addition, the amount of carbon that can be steam reformed is increased. Thereby, it is possible to increase the amount of carbon subjected to steam reforming as the temperature of the reforming unit 20c increases while reliably avoiding the risk of carbon deposition in the reforming unit 20c.

Furthermore, in the present embodiment at time t6 in FIG. 9, when the temperature detected by the power generation chamber temperature sensor 142 reaches about 400 ° C. or more, the process shifts from the ATR2 process to the ATR3 process. Accordingly, the fuel supply amount is changed from 5.0 L / min to 4.0 L / min, and the reforming air supply amount is changed from 9.0 L / min to 6.5 L / min. Also, the previous values are maintained for the water supply amount and the power generation air supply amount. This increases the steam / carbon ratio S / C in the ATR3 step to 0.80, while the reforming air to carbon ratio O ₂ / C is reduced to 0.29.

  Furthermore, when the temperature detected by the power generation chamber temperature sensor 142 reaches about 550 ° C. or higher at time t7 in FIG. 9, the process proceeds to the SR1 step. Along with this, the fuel supply amount is changed from 4.0 L / min to 3.0 L / min, and the water supply amount is changed from 3.0 cc / min to 7.0 cc / min. Further, the supply of the reforming air is stopped, and the power supply air supply amount is maintained at the previous value. As a result, in the SR1 process, steam reforming occurs exclusively in the reforming unit 20c, and the ratio S / C of steam to carbon is 2 which is appropriate for steam reforming the total amount of supplied fuel. .49. At time t7 in FIG. 9, since the temperature of both the reformer 20 and the fuel cell stack 14 is sufficiently increased, the steam reforming is performed even if the partial oxidation reforming reaction has not occurred in the reforming unit 20c. The reaction can be generated stably.

Next, at time t8 in FIG. 9, when the temperature detected by the power generation chamber temperature sensor 142 reaches about 600 ° C. or higher, the process proceeds to the SR2 step. Accordingly, the fuel supply amount is changed from 3.0 L / min to 2.5 L / min, and the water supply amount is changed from 7.0 cc / min to 6.0 cc / min.
In addition, the previous value of the power supply air supply amount is maintained. Thereby, in the SR2 step, the ratio S / C of water vapor to carbon is set to 2.56.

  Further, after executing the SR2 process for a predetermined time, the process proceeds to the power generation process. In the power generation process, power is extracted from the fuel cell stack 14 to the inverter 54 (FIG. 8), and power generation is started. In the power generation process, the reforming unit 20c reforms the fuel exclusively by steam reforming. Further, during the power generation operation, the fuel supply amount, the power generation air supply amount, and the water supply amount are changed in accordance with the output power required for the fuel cell module 2. Further, during the power generation operation, the control unit 110 sets the fuel supply amount, the power generation air supply amount, and the water supply amount so that they are within an appropriate temperature range in which the temperature of the fuel cell stack 14 is within a predetermined power generation temperature range. Is controlling.

  Next, the ignition process in the present embodiment will be described with reference to FIGS. FIG. 10 is an explanatory diagram of the ignition rod 83b and the shielding plate 100 of the ignition device 83 disposed on the fuel cell assembly 12, and FIG. 11 is an explanatory diagram showing the operation in the ignition process.

  As shown in FIG. 10, in the present embodiment, among the plurality of fuel cell units 16 arranged in a matrix, the four adjacent fuel cell units 16 a to 16 d positioned at the substantially rectangular apexes are shielded. 100 is attached. The shielding plate 100 covers the four fuel cell units 16a to 16d in a top view. A gap is preferably formed between the twelve fuel cell units 16 around the fuel cell units 16a to 16d and the shielding plate 100 in a top view, but may partially overlap. .

  Further, the fuel cell units 16a to 16d are not located at the end of the fuel cell assembly 12 so that the flow of the oxidant gas that passes upward across the peripheral edge of the shielding plate 100 is symmetrical. It is preferable. Therefore, in this embodiment, the shielding plate 100 is attached to the second and third fuel cell units 16a to 16d from the endmost fuel cell unit 16, but for example, the third and fourth It may be attached to the fourth four fuel cell units 16. Further, in the present embodiment, the shielding plate 100 is attached to the four fuel cell units 16, but the present invention is not limited to this, and it is only necessary that a plurality of fuel cell units 16 are attached. Further, in this embodiment, the shielding plate 100 has a substantially rectangular outer shape when viewed from above, but is not limited thereto, and has various outer shapes such as a substantially circular shape, an elliptical shape, a rhombus shape, a trapezoidal shape, and a parallelogram shape. It is also possible to select a plurality of fuel cell units 16 having an arbitrary arrangement according to the outer shape. Furthermore, it is preferable to arrange the shielding plate 100 at a position close to the center of the fuel cell assembly 12 in order to complete quick ignition described later.

  Further, the ignition rod 83b of the ignition device 83 is configured so that the entire axial direction thereof generates heat. In particular, the tip portion 83c has the highest temperature rise and functions as an ignition unit. The ignition rod 83b extends in a substantially horizontal direction from the side surface of the housing 6 with respect to the fuel cell unit 16 extending in the vertical direction, and the tip portion 83c reaches the upper side of the shielding plate 100. Further, the tip of the ignition rod 83b reaches the central portion of the shielding plate 100 in a top view. Further, the ignition rod 83b extends through a position shifted from right above the internal flow passage narrow tube 98 so that the ignition rod 83b does not hinder the flow of off-gas ejected from the internal flow passage thin tube 98 of the fuel cell unit 16. Yes. Specifically, the ignition rod 83b is along the column direction Y of the fuel cell stack 14 in a top view and passes through an intermediate position between the adjacent fuel cell units 16a and 16b in the row direction X. Therefore, in the present embodiment, the tip portion 83c of the ignition rod 83b is located at an intermediate position between the fuel cell units 16a and 16b, and further extends to an intermediate position between the fuel cell units 16a to 16b.

  When the supply of power generation air is started at time t0 (see FIG. 9) of the start-up process and further the supply of fuel gas is started at time t1, as shown in FIG. 11 (A), the fuel gas (broken arrow) Is ejected from the internal flow passage narrow tube 98 of each fuel cell unit 16, and the power generation air (solid arrow) passes between the fuel cell units 16 and flows into the combustion chamber 18 from the power generation chamber 10.

In the region where the shielding plate 100 is not provided, the fuel gas and power generation air move upward in the combustion chamber 18 along a substantially vertical direction. On the other hand, in the vicinity of the area where the shielding plate 100 is provided, the flow direction of the fuel gas and the power generation air is inclined so as to be directed upward of the central portion of the shielding plate 100. That is, since the flow of power generation air that has passed between the fuel cell units 16a to 16d is shielded by the shielding plate 100, the space above the shielding plate 100 has a lower negative pressure than the other spaces. It becomes area | region 100a. For this reason, the power generation air that crosses the peripheral edge of the shielding plate 100 wraps around the shielding plate 100 and converges.
In the present embodiment, the shielding plate 100 has a configuration in which no hole is provided other than the through-hole for inserting the internal flow path narrow tube 98 of the fuel cell units 16a to 16d. If the flow of the oxidant gas from the chamber 10 to the combustion chamber 18 can be restricted or partially blocked, a small-diameter vent hole may be further provided.

  In addition, the fuel gas flowing out from the internal flow path narrow tube 98 of the fuel cell units 16a to 16d is moved upward in the central portion of the shielding plate 100 by the surrounding power generation air that is converged, and also in the negative pressure region. Move so as to be drawn to 100a. Thus, the fuel gas is sprayed toward the ignition rod 83b of the ignition device 83 located above the shielding plate 100.

  Therefore, before the off-gas ignition, the fuel gas flowing out from the internal flow passage narrow tube 98 of the fuel cell units 16a to 16d is concentrated around the ignition rod 83b, and the periphery of the ignition rod 83b (particularly, the shielding plate 100 and the ignition plate 100). In the space between the bars 83b, a region (fuel rich region) where the fuel gas is richer than the region above the other fuel cell unit 16 is formed. Further, the power generation air is also guided so as to surround the region where the fuel gas is rich and concentrate toward the ignition rod 83b. As described above, a region where the fuel gas is rich is formed in the vicinity of the ignition rod 83b, and the ignitability is improved by supplying sufficient power generation air.

In this state, in the ignition process, when the ignition device 83 is activated and the ignition rod 83b is in a high temperature state, the ignition rod 83b becomes a heat source, and the fuel gas around the ignition rod 83b and the fuel-rich air for power generation are rich. Combustion of the mixed gas can be easily started.
In more detail, in this embodiment, in order to ignite more reliably, first, the off-gas from the fuel cell units 16a and 16b is first ignited, and then the fuel cell units 16c are chained substantially simultaneously. And off-gas from 16d is also ignited. For this reason, the tip portion 83c of the ignition rod 83b where the temperature is most likely to rise is arranged so as to be mainly located between the adjacent fuel cell units 16a and 16b in a top view.

As shown in FIG. 11 (B), even after ignition, the combustion flame F extending from the end of each internal flow passage narrow tube 98 is directed toward the ignition rod 83b by the airflow of the power generation air and contacts the ignition rod 83b. To do. As described above, the ignition rod 83b is disposed at a portion where fuel gas is concentrated before ignition (a portion exposed to the combustion flame F after ignition) in order to facilitate ignition.
And when the front-end | tip part of the some combustion flame F overlaps, the combustion flame F larger than the combustion flame by the off gas from the single internal flow path thin tube 98 is formed. Thereby, the combustion flame F is stably maintained, and the ignitability is improved by the combustion flame F.

  That is, when a large combustion flame F is formed at the upper part of the shielding plate 100, the combustion flame F becomes a substantially large and stable heat source, and is ejected from the internal flow path narrow tube 98 of the adjacent fuel cell unit 16. The off-gas is continuously ignited, that is, the fire is transferred. At this time, even if there is a flow of oxidant gas passing around each fuel cell unit 16, all fuel cell cells can be quickly moved by a large heat source without being disturbed by the flow of oxidant gas. It becomes possible to burn off gas from the unit 16. Therefore, the ignition process can be completed in a short time, and a large amount of off-gas from the fuel cell unit 16 can be prevented from staying in the combustion chamber 18 or the power generation chamber 10.

  Thus, in the present embodiment, the shielding plate 100 is disposed on the upper part of the fuel cell assembly 12, and the shielding plate 100 is disposed only in the vicinity immediately below the ignition rod 83b. As a result, the supply of power generation air is partially blocked or restricted by the shielding plate 100. However, since the shielding plate 100 is only locally disposed in the minimum necessary portion, it is rather above the shielding plate 100 from the surroundings. The power generation air can be circulated to concentrate around the ignition rod 83b. Thereby, off-gas can also be concentrated around the ignition rod 83b. Therefore, ignition is facilitated using the ignition rod 83b as a heat source, and after the ignition, the combustion flame is also directed upward of the shielding plate 100 by the power generation air that circulates, and the ignition rod 83b is exposed to the combustion flame, and a plurality of fuels The combustion flames from the battery cell units 16a to 16d can be integrated and enlarged. In this way, since a large heat source can be formed, it is easy to transfer the off gas from the fuel cell unit 16 to which the shielding plate 100 is not attached to the off gas from all the fuel cell units 16. Can be quickly ignited.

  Further, during combustion, a sufficient amount of power generation air can be supplied above the fuel cell unit 16 in an area where the shielding plate 100 is not attached. Furthermore, since the shielding area of the shielding plate 100 is also limited in the region where the shielding plate 100 is attached, the power generation air can be supplied around the shielding plate 100 and supplied. Therefore, a sufficient amount of power generation air can be supplied above the shielding plate 100 even if there is a turbulence in the airflow, and combustion stability can be maintained.

Further, in the present embodiment, the plurality of fuel cell units 16 can be held by the shielding plate 100. Thereby, the position of the fuel cell unit 16 in the vicinity of the ignition rod 83b can be made uniform between different fuel cell devices. Therefore, it is possible to prevent a time difference from occurring in the ignition process between different fuel cell devices.
Furthermore, in this embodiment, since the shielding plate 100 is disposed only at the upper ends of some of the fuel cell units 16, the member cost can be reduced compared to the case where the shield plate 100 is disposed so as to cover all the fuel cell units 16. Can be reduced.

DESCRIPTION OF SYMBOLS 1 Solid oxide fuel cell system 2 Fuel cell module 6 Housing 7 Heat insulating material 8 Case 10 Power generation chamber 12 Fuel cell assembly 14 Fuel cell stack 16, 16a-16d Fuel cell unit 18 Combustion chamber 20 Reformer 83 Ignition device 83a Main body 83b Ignition rod 83c Tip portion 88 Internal flow path 90 Inner electrode layer 92 Outer electrode layer 94 Electrolyte layer 98 Internal flow path capillary 100 Shield plate (oxidant gas shield plate)

Claims (6)

In a fuel cell device including a fuel cell unit that generates power by a reaction between a fuel gas passing through an internal flow path and an external oxidant gas,
A fuel cell assembly comprising an array of a plurality of the fuel cell units disposed in a housing;
An oxidant gas supply means for supplying an oxidant gas to the outside of the fuel cell unit from below the housing;
The fuel gas that is located above the fuel cell assembly, passes through the internal flow path of the fuel cell unit, and flows out from the upper end of the fuel cell unit, and the oxidation gas supplied by the oxidant gas supply means A combustion section for burning the agent gas;
An ignition device having an ignition unit for igniting a mixed gas of fuel gas and oxidant gas in the combustion unit,
An oxidant gas shielding plate for blocking the flow of the oxidant gas supplied from the oxidant gas supply means to the combustion part is disposed only near the ignition part of the ignition device.
The fuel characterized in that the oxidant gas shielding plate is held with respect to the fuel cell assembly in a state where upper ends of the plurality of fuel cell units penetrate the oxidant gas shielding plate. Battery device.   2. The fuel cell device according to claim 1, wherein the ignition unit of the ignition device is disposed at a position shifted from an internal flow path of the fuel cell unit in a top view of the fuel cell device.   3. The ignition unit of the ignition device according to claim 2, wherein the ignition unit of the ignition device is disposed at a position close to an internal flow path of the plurality of adjacent fuel cell units in a top view of the fuel cell device. Fuel cell device. The plurality of fuel cell units each extend in the vertical direction, and are arranged along the vertical direction and the horizontal direction in a top view of the fuel cell device,
The oxidant gas shielding plate is substantially square in a top view of the fuel cell device, and the top ends of four fuel cell units arranged in 2 rows and 2 columns along the vertical direction and the horizontal direction in the top view. Department has through transmural,
4. The fuel cell device according to claim 3, wherein the ignition device has a probe-like ignition part extending at least to substantially the center of the oxidant gas shielding plate.   The fuel cell device according to claim 1, wherein the ignition device is a ceramic heater.   The fuel cell device according to claim 1, wherein the ignition device is a spark plug.

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