JP6474021B2 - Solid oxide fuel cell device - Google Patents

Description

  The present invention relates to a solid oxide fuel cell, and more particularly to a solid oxide fuel cell that generates power by reacting hydrogen generated by steam reforming of fuel and an oxidant 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. This is a fuel cell that generates power by supplying an oxidant (air, oxygen, etc.) to the other side to generate a power generation reaction.

  The solid oxide fuel cell device is a fuel cell device that operates at a relatively high temperature, burns off-gas that has not contributed to power generation, and raises the temperature of the reformer by the combustion flame. Further, at the time of start-up, the reforming process (ATR, SR) is changed while monitoring the temperature of the reforming catalyst filled in the reformer. Since these steps are sequentially executed according to the detection result by the temperature sensor provided in the reformer, it is necessary to measure the temperature of the reforming catalyst with high accuracy.

JP 2010-67384 A JP 2014-71959 A

  Prior document 1 discloses that the surface temperature is measured from the upper surface of a reformer in which a combustion section is disposed below to grasp the temperature of the reforming catalyst. However, when the reforming catalyst is charged into the reformer, the density of the reforming catalyst tends to be dense on the bottom side inside the reformer and sparse on the top side. When the temperature is detected, the temperature effect due to the reforming catalyst is remarkably generated from the upper surface side to the bottom surface side of the reformer. Therefore, it can be said that it is preferable to detect the temperature on the side surface side, considering that the temperature on the bottom surface side is higher in response than the temperature on the upper surface side and the combustion part is provided on the bottom surface side.

  Therefore, in order to measure the temperature of the reformer from the side surface side, the temperature sensor is pressed against the side wall surface of the reformer. However, when the temperature of the reformer is raised by the combustion flame, the temperature sensor detects the heat by the rise of the combustion gas from the side of the reformer and the radiant heat of the combustion flame. Therefore, the reformer temperature depends on the combustion state, and it becomes difficult to accurately detect the temperature of the reforming catalyst.

  Here, Patent Document 2 discloses that a thermocouple is brought into contact with the side surface of the reformer, and further, the thermocouple is covered with the side surface of the reformer and the sensor holder, thereby suppressing the influence of the combustion flame in temperature detection. Yes.

  However, in the conventional method of measuring the temperature of the reforming catalyst by abutting a temperature sensor on the outer wall surface of the reformer, the detected value is not stabilized by detecting fluctuations in the combustion flame, or the high temperature directly heated is modified. It is inevitable that a temperature higher than that of the reforming catalyst is detected due to the influence of the quality device. Therefore, in order to accurately measure the temperature of the reforming catalyst, it is necessary to reduce the influence of the combustion flame.

  Therefore, an object of the present invention is to provide a solid oxide fuel cell in which the temperature sensor is not affected by the combustion flame and can accurately measure the temperature of the reforming catalyst.

In order to solve the above-described problem, the present invention provides a solid oxide fuel cell device that generates electric power using a reformed fuel gas and an oxidant gas, and a plurality of fuel cells extending in the vertical direction;
A combustion section that is provided above the plurality of fuel cells and that burns the fuel gas remaining without being used for power generation in the plurality of fuel cells ; and A reformer disposed above and filled with a reforming catalyst for reforming the fuel gas; and a temperature sensor for detecting the temperature of the reforming catalyst, the temperature sensor being inserted The temperature of the reforming catalyst is detected via a member, and the insertion member is hollow and closed at the tip, and is inserted into a side surface of the reformer, and the internal direction of the reformer The protrusion protrudes so as to become thinner toward the inner end of the reformer, and further, the tip of the protrusion is linearly inclined. And the projecting portion is the reformer in a top view. It is characterized in that the diameter toward the inside direction is increased.

According to the present invention configured as described above, by arranging the temperature sensor inside the insertion member, the temperature sensor is covered inside the reformer, and the temperature sensor is not directly exposed to the combustion flame. The temperature of the reforming catalyst can be accurately measured without being affected by the above. Furthermore, since the distance between the reforming catalyst and the temperature sensor is shortened by projecting the insertion member toward the inside of the reformer, it is possible to receive more heat due to heat conduction from the reforming catalyst. The temperature of the reforming catalyst can be measured well. In addition, by inclining the front end surface of the protrusion so as to become narrower toward the inside of the reformer, the temperature sensor can be guided to the front end surface that receives the most heat from the reforming catalyst. It is possible to accurately measure the temperature by sufficiently contacting the tip surface of the protrusion. Further, by linearly inclining the tip of the protruding portion, the number of contact points with the reforming catalyst can be increased, and the temperature of the reforming catalyst can be measured with higher accuracy. In addition, since the temperature sensor can be fixed to the corner of the front end surface of the projecting portion by increasing the diameter toward the front end of the projecting portion in the top view, the temperature sensor and the insertion member can be reliably brought into contact. Thus, the temperature of the reforming catalyst can be measured with high accuracy.

In the present invention, the protrusion is preferably in direct contact with the reforming catalyst.
According to the present invention configured as described above, the insertion member protruding toward the interior of the reformer is in direct contact with the reforming catalyst over the entire surface of the protrusion, and the temperature is measured via the insertion member. Thus, the temperature closer to the reforming catalyst can be accurately measured.

In the present invention, the second insertion member having the same shape as the insertion member is preferably provided on the wall surface of the reformer so that the flow of the fuel gas inside the reformer is uniform.
According to the present invention configured as described above, not only the insertion member for installing the temperature sensor but also the flow of the fuel gas inside the reformer is provided so as to be uniform. The flow of the fuel gas inside can be made symmetrical with respect to the reforming catalyst, and there is no reforming bias due to the drift of the fuel gas in the reformer due to the insertion member, and the catalyst is partially Deterioration can be prevented.

  According to the present invention, the catalyst temperature of the reformer can be accurately measured without being affected by fluctuations in the combustion section.

1 is an overall configuration diagram showing a fuel cell device according to an embodiment of the present invention. It is front sectional drawing which shows the fuel cell module of the fuel cell apparatus by one Embodiment of this 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 fuel cell device by one embodiment of the present invention. It is a perspective view which shows the fuel cell stack of the fuel cell apparatus by one Embodiment of this invention. 1 is a block diagram showing a fuel cell device according to an embodiment of the present invention. 1 is a perspective view of a reformer of a fuel cell device according to an embodiment of the present invention. It is a top sectional view showing a flow of fuel inside a reformer of a fuel cell device by one embodiment of the present invention. It is sectional drawing in the top view (a) and side view (b) of the insertion member of the fuel cell apparatus by one Embodiment of this invention. It is a perspective view which shows the metal case and the air heat exchanger which were accommodated in the housing of the fuel cell apparatus by one Embodiment of this invention. It is sectional drawing which shows the positional relationship of the heat insulating material for heat exchangers of the fuel cell apparatus by one Embodiment of this invention, and an evaporation part.

Next, a solid oxide fuel cell (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 (SOFC) according to an embodiment of the present invention. As shown in FIG. 1, a solid oxide fuel cell (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 ten fuel cell stacks 14 (see FIG. 5), and the fuel cell stack 14 includes 16 fuel cell unit 16 (see FIG. 4). Yes. Thus, the fuel cell assembly 12 has 160 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 a solid oxide fuel cell (SOFC) fuel cell module according to an embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a side sectional view showing a solid oxide fuel cell (SOFC) fuel cell module according to an embodiment of the present invention, and FIG. 3 is a sectional view taken along line III-III in FIG. .
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 reforming unit 20c. 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. The insertion member 151 provided in the reforming part 20c will be described in detail later.

  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. The adjustment of the channel resistance will be described later.

  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 illustrating a fuel cell unit of a solid oxide fuel cell (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 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 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. At the center of the inner electrode terminal 86, a fuel gas channel capillary 98 that communicates with the fuel gas channel 88 of the inner electrode layer 90 is formed.

  The fuel gas 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. For this reason, a predetermined pressure loss occurs in the flow of the fuel gas flowing from the manifold 66 (FIG. 2) into the fuel gas passage 88 through the fuel gas passage narrow tube 98 of the lower inner electrode terminal 86. . Accordingly, the fuel gas flow passage narrow tube 98 of the lower inner electrode terminal 86 acts as an inflow side flow passage resistance portion, and the flow passage resistance is set to a predetermined value. Further, a predetermined pressure loss also occurs in the flow of the fuel gas flowing out from the fuel gas flow path 88 to the combustion chamber 18 (FIG. 2) through the fuel gas flow path narrow tube 98 of the upper inner electrode terminal 86. Therefore, the fuel gas flow passage narrow tube 98 of the upper inner electrode terminal 86 acts as an outflow side flow passage resistance portion, and the flow passage 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 (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 is supported at its lower end by a rectangular lower support plate 68 (FIG. 2) made of ceramic, and at the upper end, four fuel cell units 16 at both end portions are provided, each having a generally square shape. It is supported by the upper support plate 100. The lower support plate 68 and the upper support plate 100 are formed with through holes through which the inner electrode terminal 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 160 fuel cell units 16 are connected in series. It has come to be.

Next, sensors and the like attached to the solid oxide fuel cell (SOFC) according to the present embodiment will be described with reference to FIG. FIG. 6 is a block diagram illustrating a solid oxide fuel cell (SOFC) according to an embodiment of the present invention.
As shown in FIG. 6, the solid oxide fuel cell 1 includes a control unit 110, and the control unit 110 includes operation buttons such as “ON” and “OFF” for operation by the user. An 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 current and voltage of the inverter 54 and the distribution board (not shown).
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 reforming catalyst filled in the reformer 20. Here, the reformer temperature sensor 148 is configured by a thermocouple, but any device that detects temperature may be used.
The outside air temperature sensor 150 is for detecting the temperature of the outside air when the solid oxide fuel cell (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, a detailed configuration of the reformer 20 will be described with reference to FIGS.
7 is a perspective view of the reformer 20, and FIG. 8 is a plan sectional view showing the flow of fuel inside the reformer 20. As shown in FIG.

(Example inside the reformer)
As shown in FIG. 7, the reformer 20 is a rectangular parallelepiped metal box, and is filled with a spherical reforming catalyst for reforming fuel (not shown). In FIG. 7, the reformer 20 is shown as a rectangular parallelepiped shape, but is not limited thereto, and may be any shape according to the shape of the module, such as a cube shape. A reformer introduction pipe 62 for introducing water, fuel, and reforming air is connected to the upstream side of the reformer 20. Note that reforming air is not required when a steam reforming reaction is caused by water and fuel. Further, a fuel gas supply pipe 64 for supplying internally reformed fuel to the manifold 66 is connected to the downstream side of the reformer 20.

  As shown in FIG. 8, inside the reformer 20, an evaporation unit 20a that is an evaporation chamber is provided on the upstream side, and a mixing unit 20b is provided on the downstream side adjacent to the evaporation unit 20a. ing. Further, a reforming section 20c is provided on the downstream side adjacent to the mixing section 20b. A meandering passage is formed in the evaporation portion 20a by arranging a plurality of partition plates. The water introduced into the reformer 20 is evaporated or heated in the evaporation unit 20a in a state where the temperature is increased, and becomes water vapor. Furthermore, the mixing part 20b is comprised from the chamber which has a predetermined | prescribed volume, and the meandering channel | path is formed also in the inside by arrange | positioning a some partition plate. The fuel gas introduced into the reformer 20 is mixed with the steam generated in the evaporation unit 20a while passing through the winding path of the mixing unit 20b.

On the other hand, a meandering passage is formed in the reforming section 20c by arranging a plurality of partition plates, and the passage is filled with a catalyst. When a mixed gas of fuel gas, water vapor, and reforming air is introduced through the evaporation unit 20a and the mixing unit 20b, a partial oxidation reforming reaction and a steam reforming reaction (ATR) occur in the reforming unit 20c. . Further, when a mixed gas of fuel gas and steam is introduced, a steam reforming reaction (SR) occurs in the reforming unit 20c.
In this embodiment, the evaporation unit, the mixing unit, and the reforming unit are integrally configured to form one reformer. However, as a modification, a reformer including only the reforming unit is used. It is also possible to provide a mixer and an evaporator separately from this upstream side.

As shown in FIG. 8, the fuel gas, water, and reforming air introduced into the evaporation section 20a of the reformer 20 meander in the transverse direction of the reformer 20, and the water introduced during this period. Evaporates into water vapor. An evaporation / mixing unit partition 20d is provided between the evaporation unit 20a and the mixing unit 20b, and a partition opening 20e is provided in the evaporation / mixing unit partition 20d. This partition opening 20e is a rectangular opening provided in an upper half of the half of one side of the evaporation / mixing section partition 20d.
Further, a mixing / reforming section partition wall 20f is provided between the mixing section 20b and the reforming section 20c, and a narrow flow path is formed by providing a large number of communication holes 20g in the mixing / reforming section partition wall 20f. Has been. The fuel gas or the like mixed in the mixing unit 20b flows into the reforming unit 20c through these communication holes 20g.

  The fuel or the like that has flowed into the reforming unit 20c flows in the longitudinal direction in the center of the reforming unit 20c, and then splits into two to be folded back. Then, they are merged and flow into the fuel gas supply pipe 64 (see FIGS. 7 and 8). The fuel is reformed by the catalyst filled in the passage while passing through the meandering passage. In the evaporation unit 20a, bumping may occur in which a certain amount of water rapidly evaporates in a short time, and the internal pressure may increase. However, since the mixing unit 20b has a chamber with a predetermined volume and the mixing / reforming unit partition wall 20f has a narrow flow path, the reforming unit 20c has a sudden pressure fluctuation in the evaporation unit 20a. The influence of is difficult to reach. Therefore, the chamber of the mixing unit 20b and the narrow channel of the mixing / reforming unit partition 20f function as pressure fluctuation absorbing means.

  Here, more specific configurations of the reformer 20, the reformer temperature sensor 148, and the insertion member 151 will be described with reference to FIGS. The reformer 20 includes an insertion member 151 for inserting the reformer temperature sensor 148 into the reformer. The insertion member 151 is made of the same material as that of the reformer 20 and has the same heat transfer performance. Therefore, since the members have the same thermal expansion coefficient, the members are not damaged even if they are thermally expanded. Here, it is shown that the material is made of the same material, but the material is not limited to this as long as it has heat transfer performance.

The insertion member 151 is fixed to the downstream side surface of the reforming portion 20c by welding or the like so that the cylindrical axis direction is perpendicular to the side surface, and the hermeticity inside the reformer 20 is maintained. Further, the insertion member 151 has a cylindrical shape larger than the outer diameter of the reformer temperature sensor 148, the tip inserted into the reforming portion 20c is closed, and the inside is hollow. Further, a protrusion 151 a is provided so as to incline toward the inside of the reformer 20. The reformer temperature sensor 148 is inserted into the insertion member 151 provided on the side surface of the reformer 20 and measures the reforming catalyst temperature via the insertion member 151. Accordingly, since the temperature sensor is covered inside the reformer 20, the reformer temperature sensor 148 is not exposed to the combustion flame, and the temperature of the reforming catalyst is accurately measured without being affected by the combustion flame. be able to.
In the present embodiment, the insertion member 151 is shown as a cylindrical shape, but the insertion member 151 is not limited to a cylindrical shape as long as the inside is hollow.

  Since the protrusion 151a protrudes inside the reforming part 20c, the plurality of spherical reforming catalysts filled in the reforming part 20c and the protrusion 151a are in direct contact. Therefore, the entire surface of the protrusion 151a contacts the reforming catalyst. Therefore, it is possible to detect a value closer to the temperature of the reforming catalyst.

9A shows a top view of the insertion member 151, and FIG. 9B shows a side view of the insertion member 151. As shown in FIG. 9A, the tip of the protrusion 151 a has a diameter that increases toward the inside of the reformer 20. For this reason, the number of contact points between the reforming catalyst and the protrusion increases, and the temperature of the reforming catalyst can be detected with higher accuracy. Furthermore, since the diameter of the protrusion 151a increases toward the tip, the reformer temperature sensor 148 can be fixed at the corner of the tip, and good contact can be maintained.
As shown in FIG. 9B, the protrusion 151 a is closed at the tip by welding or the like, and is inclined linearly so that the tip becomes narrower toward the inside of the reformer 20. The reformer temperature sensor 148 measures the temperature in a state where it is abutted against the tip of the protrusion 151a. Therefore, no matter how the reformer temperature sensor is inserted into the insertion member 151, the reformer temperature sensor 148 can be guided to the tip surface of the protrusion 151 a, so that the contact between the reformer temperature sensor 148 and the insertion member 151 is good. Can be.

Also, as shown in FIG. 8, a second insertion member 152 having the same shape as the insertion member 151 is provided on the side surface of the reformer 20 facing the insertion member 151. In FIG. Similarly to the insertion member 151, the second insertion member 152 is also installed. Therefore, by providing the insertion member 151, the flow of the fuel gas inside the reforming unit 20 c changes, but the reformer 20 that opposes the flow of the fuel gas inside the reforming unit 20 c to the insertion member 151. By providing the second insertion member 152 on the wall surface, the inner wall surface of the reforming portion 20c provided with the insertion member 151 and the inner wall surface of the reforming portion 20c provided with the second insertion member 152 are provided. The flow of the flowing fuel gas can be made the same, and the flow of the fuel gas can be made uniform with respect to the reforming catalyst. Accordingly, it is possible to prevent the reforming reaction from being biased toward any wall surface and locally degrading the reforming catalyst.
However, the second insertion member 152 disposed on the side surface of the reformer 20 is not necessarily provided at a position symmetrical to the insertion member 151. That is, since the internal structure of the reformer can be designed as appropriate, the internal structure of the reformer does not necessarily have a symmetrical structure in the front-rear direction or the left-right direction. For this reason, the 2nd insertion member 152 can be provided in the optimal position where the deviation of the fuel gas which flows through the inside becomes the minimum according to the shape or structure of a reformer.
Furthermore, the reformer temperature sensor 148 may be installed in both the insertion member 151 and the second insertion member 152, or the reformer temperature sensor 148 may be installed in either one.

  Further, in FIG. 8, the insertion member 151 is installed on the side surface of the reformer 20, and a part of the plug member 151 protrudes toward the inside of the reformer 20. The portion not inserted is exposed to the outside of the reformer 20. The exposed portion of the insertion member 151 is substantially orthogonal to the direction of the combustion gas flowing along the side surface of the reformer. Therefore, the influence of the combustion flame on the reformer temperature sensor 148 provided inside the insertion member 151 can be reduced, and as a result, the temperature of the reforming catalyst can be accurately measured.

  Next, referring to FIGS. 10 and 11 again, and referring again to FIGS. 2 and 3, the structure of the air heat exchanger 22 which is a heat exchanger for the power generation oxidant gas will be described in detail. FIG. 10 is a perspective view showing the metal case 8 and the air heat exchanger 22 housed in the housing 6. FIG. 11 is a cross-sectional view showing the positional relationship between the evaporation chamber heat insulating material and the evaporation section.

  As shown in FIG. 10, the air heat exchanger 22 is a heat exchanger disposed above the case 8 in the fuel cell module 2. Further, as shown in FIGS. 2 and 3, a combustion chamber 18 is formed inside the case 8, and a plurality of fuel cell units 16, a reformer 20 and the like are accommodated therein. 22 is located above these. The air heat exchanger 22 collects and uses the heat of the combustion gas that is combusted in the combustion chamber 18 and discharged as exhaust gas so as to preheat the power generation air introduced into the fuel cell module 2. It is configured. Further, as shown in FIG. 10, an evaporation chamber heat insulating material 23, which is an internal heat insulating material, is disposed between the upper surface of the case 8 and the bottom surface of the air heat exchanger 22 so as to be sandwiched between them. Has been. That is, the evaporation chamber heat insulating material 23 is disposed between the reformer 20 and the air heat exchanger 22. Furthermore, the outside of the air heat exchanger 22 and the case 8 shown in FIG. 10 is covered with a heat insulating material 7 as an outer heat insulating material (FIG. 2).

  As shown in FIGS. 2 and 3, the air heat exchanger 22 includes a plurality of combustion gas pipes 70 and a power generation air flow path 72. As shown in FIG. 2, an exhaust gas collecting chamber 78 is provided at one end of the plurality of combustion gas pipes 70, and the exhaust gas collecting chamber 78 is communicated with each combustion gas pipe 70. ing. Further, an exhaust gas discharge pipe 82 is connected to the exhaust gas collecting chamber 78. Further, the other end of each combustion gas pipe 70 is open, and this open end communicates with the combustion chamber 18 in the case 8 via a communication opening 8 a formed on the upper surface of the case 8. Has been.

  The combustion gas pipe 70 is a plurality of metal circular pipes oriented in the horizontal direction, and the circular pipes are arranged in parallel. On the other hand, the power generation air flow path 72 is constituted by a space outside each combustion gas pipe 70. A power generation air introduction pipe 74 (FIG. 10) is connected to the end of the power generation air flow path 72 on the exhaust gas discharge pipe 82 side so that the air outside the fuel cell module 2 is used for power generation. The air is introduced into the power generation air flow path 72 through the air introduction pipe 74. As shown in FIG. 10, the power generation air introduction pipe 74 protrudes in the horizontal direction from the air heat exchanger 22 in parallel with the exhaust gas discharge pipe 82. Further, a pair of communication flow paths 76 (FIGS. 3 and 10) are connected to both side surfaces of the other end of the power generation air flow path 72, and the power generation air flow path 72 and each communication flow path 76 are connected. Are communicated with each other via an exit port 76a.

  As shown in FIG. 3, a power generation air supply passage 77 is provided on each side surface of the case 8. Each communication channel 76 provided on both side surfaces of the air heat exchanger 22 communicates with an upper portion of a power generation air supply channel 77 provided on both side surfaces of the case 8. In addition, a large number of air outlets 77 a are arranged in the horizontal direction at the lower portion of each power generation air supply passage 77. The power generation air supplied through each power generation air supply path 77 is injected toward the lower side surface of the fuel cell stack 14 in the fuel cell module 2 from a large number of air outlets 77a.

A rectifying plate 21 that is a partition wall is attached to the ceiling surface inside the case 8, and the rectifying plate 21 has an opening 21 a.
The rectifying plate 21 is a plate member disposed horizontally between the ceiling surface of the case 8 and the reformer 20. The rectifying plate 21 is configured to adjust the flow of the gas flowing upward from the combustion chamber 18 and to guide it to the inlet of the air heat exchanger 22 (communication opening 8a in FIG. 2). The power generation air and the combustion gas traveling upward from the combustion chamber 18 flow into the upper side of the rectifying plate 21 through the opening 21 a provided in the center of the rectifying plate 21, and the upper surface of the rectifying plate 21 and the ceiling surface of the case 8. 2 flows to the left in FIG. 2 and is led to the inlet of the heat exchanger 22 for air. Further, as shown in FIG. 11, the opening 21a is provided above the reforming unit 20c of the reformer 20, and the gas rising through the opening 21a is on the side opposite to the evaporation unit 20a. , Flows to the left exhaust passage 21b in FIGS. For this reason, the space above the evaporation unit 20a (the right side in FIGS. 2 and 11) acts as a gas retention space 21c in which the flow of exhaust gas is slower than the space above the reforming unit 20c and the flow of exhaust gas is stagnant.

Further, a vertical wall 21d is provided at the edge of the opening 21a of the rectifying plate 21 over the entire circumference, and the vertical wall 21d allows the exhaust above the rectifying plate 21 from the space below the rectifying plate 21. The flow path flowing into the passage 21b is narrowed. Further, a falling wall 8b (FIG. 2) is provided over the entire circumference at the edge of the communication opening 8a that allows the exhaust passage 21b and the air heat exchanger 22 to communicate with each other. The flow path flowing into the air heat exchanger 22 is narrowed. By providing the vertical wall 21d and the falling wall 8b, the flow resistance in the exhaust passage from the combustion chamber 18 to the outside of the fuel cell module 2 through the air heat exchanger 22 is adjusted. The adjustment of the channel resistance will be described later.

The heat insulating material 23 for the evaporation chamber is a heat insulating material attached to the bottom surface of the air heat exchanger 22 so as to substantially cover the whole. Therefore, the heat insulating material 23 for evaporation chamber is arrange | positioned over the whole evaporation part 20a. The evaporating chamber heat insulating material 23 is formed so that the high-temperature gas in the exhaust passage 21 b and the gas retention space 21 c formed between the upper surface of the rectifying plate 21 and the ceiling surface of the case 8 flows on the bottom surface of the air heat exchanger 22. It arrange | positions so that it may suppress direct heating. For this reason, during the operation of the fuel cell module 2, the heat directly transferred to the bottom surface of the air heat exchanger 22 from the exhaust gas remaining in the exhaust passage above the evaporation unit 20a is reduced, and the surroundings of the evaporation unit 20a are reduced. The temperature tends to rise. In addition, after the fuel cell module 2 is stopped, the evaporation chamber heat insulating material 23 is disposed, so that heat dissipation from the reformer 20 is suppressed, that is, the heat around the evaporation unit 20a is used for air. The heat exchanger 22 is less likely to be deprived, and the temperature drop of the evaporation unit 20a is moderated.

  In addition, the heat insulating material 23 for the evaporation chamber includes a heat insulating material 7 that is an outer heat insulating material covering the case 8 of the fuel cell module 2 and the entire air heat exchanger 22 in order to suppress the dissipation of heat to the outside air. Apart from this, it is a heat insulating material arranged inside the heat insulating material 7. The heat insulating material 7 is configured to have higher heat insulating properties than the heat insulating material 23 for the evaporation chamber. That is, the thermal resistance between the inner surface and the outer surface of the heat insulating material 7 is larger than the thermal resistance between the upper surface and the lower surface of the evaporation chamber heat insulating material 23. That is, when the heat insulating material 7 and the evaporation chamber heat insulating material 23 are made of the same material, the heat insulating material 7 is made thicker than the evaporation chamber heat insulating material 23.

Next, the flow of fuel, power generation air, and exhaust gas during the power generation operation of the solid oxide fuel cell 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, the effect of the insertion member 151 containing the above reformer temperature sensor 148 will be described with reference to FIGS. 2, 8, and 9.
In the present embodiment, by arranging the reformer temperature sensor 148 inside the insertion member 151, the reformer temperature sensor 148 is covered inside the reformer 20, and the reformer temperature sensor 148 becomes a combustion flame. Thus, the temperature of the reforming catalyst can be measured more accurately without being affected by the combustion flame. Furthermore, since the insertion member 151 protrudes toward the interior of the reformer and the distance between the reforming catalyst and the reformer temperature sensor 148 is shortened, more heat can be received due to heat conduction from the reforming catalyst. Therefore, the temperature of the reforming catalyst can be measured with high accuracy.

  Furthermore, the insertion member 151 that protrudes toward the inside of the reformer is in direct contact with the reforming catalyst over the entire surface of the protrusion 151a. By measuring the temperature through the insertion member 151, the insertion member 151 can be made more reformed. Close temperature can be accurately measured.

In addition, as shown in FIG. 9B, the tip surface of the protrusion 151a is inclined so as to become narrower toward the inside of the reformer, so that the tip surface receiving the heat most from the reforming catalyst is obtained. The reformer temperature sensor 148 can be induced, and the reformer temperature sensor 148 can be sufficiently brought into contact with the distal end surface of the insertion member 151 to accurately measure the temperature.
Furthermore, when the tip of the protrusion 151a is formed in a spherical shape, the number of contact points with the spherical reforming catalyst is small and the temperature of the catalyst cannot be measured with high accuracy, but the tip of the protrusion 151a is inclined linearly. By doing so, the number of contact points with the reforming catalyst can be increased, and the temperature of the reforming catalyst can be measured with higher accuracy.

As shown in FIG. 9A, the reformer temperature sensor 148 can be fixed to the corner of the tip surface of the protrusion 151a by increasing the diameter toward the tip of the protrusion 151a. The quality device temperature sensor 148 and the insertion member 151 can be reliably brought into contact with each other, and the temperature can be accurately measured.
Furthermore, since the contact area between the protrusion 151a and the reforming catalyst increases, the temperature of the reforming catalyst can be measured with higher accuracy.

  Further, as shown in FIG. 8, not only the insertion member 151 for installing the reformer temperature sensor 148, but also the second insertion member 152 so as to make the flow of fuel gas inside the reformer uniform. Since it is provided, the flow of the fuel gas inside the reformer 20 can be made symmetric with respect to the reforming catalyst. Accordingly, the reforming bias due to the drift of the fuel gas in the reforming portion 20c caused by the insertion member 151 does not occur, and the catalyst can be prevented from partially deteriorating.

1 Solid Oxide Fuel Cell 2 Fuel Cell Module 4 Auxiliary Unit 7 Heat Insulation (Heat Storage Material)
8 Case 8a Communication opening 8b Falling wall 10 Power generation chamber 12 Fuel cell assembly 14 Fuel cell stack 16 Fuel cell unit (solid oxide fuel cell)
18 Combustion chamber (combustion section)
20 Reformer 20a Evaporating section (evaporating chamber)
20b Mixing part (pressure fluctuation absorbing means)
20c reforming part 20d evaporation / mixing part partition 20e partition opening 20f mixing / reforming part partition (pressure fluctuation absorbing means)
20g communication hole (narrow channel)
21 Rectifier plate (partition wall)
21a Opening 21b Exhaust passage 21c Gas residence space 21d Vertical wall 22 Air heat exchanger (heat exchanger)
23 Heat insulating material for evaporation chamber (internal heat insulating material)
24 Water supply source 26 Pure water tank 28 Water flow rate adjustment unit (water supply device)
30 Fuel supply source 38 Fuel flow rate adjustment unit (fuel supply device)
39 Valve 40 Air supply source 44 Air flow rate adjustment unit for reforming (oxidizing gas supply device for reforming)
45 Air flow adjustment unit for power generation (oxidizer gas supply device for power generation)
46 1st heater 48 2nd heater 50 Hot water production apparatus (heat exchanger for exhaust heat recovery)
52 Control box 54 Inverter 56 Reformer temperature sensor insertion pipe 62 Reformer introduction pipe (water introduction pipe, preheating part, dew condensation part)
62a T-shaped tube (condensation part)
63a Water supply pipe 63b Fuel gas supply pipe 64 Fuel gas supply pipe 64c Pressure fluctuation suppressing flow path resistance 66 Manifold (dispersion chamber)
76 Air introduction pipe 76a Air outlet 82 Exhaust gas discharge pipe 83 Ignition device 84 Fuel cell 85 Exhaust valve 86 Inner electrode terminal (cap)
98 Fuel gas channel narrow tube (inflow side channel resistance, outflow side channel resistance, throttle channel, acceleration unit)
110 Controller (Controller)
110a Shutdown stop circuit 110b Pressure hold control circuit 112 Operation device 114 Display device 116 Alarm device 126 Power state detection sensor (demand power detection means)
132 Fuel flow sensor (fuel supply detection sensor)
138 Pressure sensor (reformer pressure sensor)
142 Power generation chamber temperature sensor (temperature detection means)
148 Reformer Temperature Sensor 150 Outside Air Temperature Sensor 151 Insertion Member 151a Protrusion 152 Second Insertion Member

Claims (3)

In a solid oxide fuel cell device that generates electric power using a reformed fuel gas and an oxidant gas,
A plurality of fuel cells extending in the vertical direction;
A combustion unit that is provided above the plurality of fuel cells and burns the fuel gas remaining without being used for power generation in the plurality of fuel cells;
A reformer disposed above the combustion section so as to receive the heat of the combustion section and filled with a reforming catalyst for reforming the fuel gas;
A temperature sensor for detecting the temperature of the reforming catalyst;
With
The temperature sensor detects the temperature of the reforming catalyst via an insertion member,
The male member are those inside the tip cavity closed been and is inserted into a side of the reformer, the protruding portion that protrudes inward is provided in the reformer, the protrusion The portion protrudes so as to become thinner toward the inner end of the reformer, and further, the tip of the protrusion is inclined linearly, and the protrusion is viewed from above in the reformer. A solid oxide fuel cell device characterized in that the diameter increases toward the inside of the fuel cell. The solid oxide fuel cell device according to claim 1, wherein the protrusion is in direct contact with the reforming catalyst. A second insertion member having the same shape as the insertion member is provided on the wall surface of the reformer so that the flow of the fuel gas inside the reformer is uniform. The solid oxide fuel cell device according to any one of claims 1 to 2 .

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