JP6504356B2 - Solid oxide fuel cell device - Google Patents

Description

  The present invention relates to a solid oxide fuel cell device, and more particularly to a solid oxide fuel cell device that generates electric power by the reaction of a fuel gas obtained by reforming a raw material gas and air.

  A solid oxide fuel cell device (Solid Oxide Fuel Cell: hereinafter referred to as "SOFC") uses an oxide ion conductive solid electrolyte as an electrolyte, with electrodes attached on both sides, and supplies fuel gas on one side. The fuel cell is operated at a relatively high temperature by supplying an oxidant gas (air, oxygen, etc.) to the other side.

  Conventionally, in a solid oxide fuel cell device, the temperature of an oxidizing gas (air) is raised by using the heat of exhaust gas generated by burning off gas not used for power generation, The fuel cells are being supplied. As a configuration for performing heat exchange between such exhaust gas and oxidizing gas, for example, Patent Document 1 discloses an exhaust passage for discharging exhaust gas from the storage chamber outside the storage chamber for storing the cell stack. There is disclosed an apparatus which is formed and on the outside of which an air passage for supplying an oxidizing gas into the storage chamber is formed. Moreover, in the apparatus of patent document 1, the vaporizer which produces | generates water vapor | steam in the exhaust passage is provided. According to such a configuration, steam can be generated by the exhaust gas in the exhaust passage, and the exhaust passage and the air passage are provided adjacent to each other, so the exhaust gas passing through the exhaust passage and the air passage can be generated. Heat exchange takes place with the generating air passing through.

JP 2012-221659 A

  Here, in the device described in Patent Document 1, the exhaust gas flows downward from above in the exhaust passage, and heat exchange with air in the air passage causes the exhaust gas in the exhaust passage to flow from above. Uneven temperature in the vertical direction is generated such that the temperature decreases downward. Also, the air flows from the bottom to the top of the air passage, and heat is exchanged with the exhaust gas in the exhaust passage, so that the temperature of the air in the air passage decreases in temperature from the top to the bottom. Temperature unevenness has occurred.

  By the way, in order to manufacture the fuel cell apparatus as described above for general consumers (for home use), it is necessary to achieve miniaturization while securing performance. In order to miniaturize the module case, the distance between the fuel cell unit and the side plate of the module case must be necessarily reduced. However, if the distance between the fuel cell unit and the side plate of the module case is reduced as described above, the fuel cell unit is susceptible to the influence of the temperature variation of the exhaust gas flowing in the exhaust passage and the air flowing in the air passage. Specifically, as described above, in the fuel cell device described in Patent Document 1, the temperature unevenness in the vertical direction is generated in the exhaust gas flowing in the exhaust passage and the air flowing in the air passage. Temperature unevenness may occur in the vertical direction in the unit. Furthermore, the fuel cell unit disposed in the vicinity of the side plate in plan view is more susceptible to the temperature unevenness of the exhaust gas and the air than the fuel cell unit disposed in the vicinity of the center in plan view. Uneven temperature in the lateral direction also occurs between the fuel cell unit and the fuel cell unit disposed near the center in plan view. Such non-uniformity in temperature distribution causes deterioration of the fuel cell unit.

  Further, in the configuration described in the above-mentioned Patent Document 1, since the carburetor is provided in the exhaust passage, the exhaust heat of the exhaust gas is steam before the heat exchange with the air in the air passage is performed. Since the gas is used for vaporization, the temperature of the exhaust gas is lowered. For this reason, the heat exchange performance between the exhaust gas and the air is reduced.

  The present invention reduces the size and cost of a solid oxide fuel cell device that exchanges heat between an outer air passage provided along the side wall of a module case and an inner exhaust passage. In addition, it aims at securing sufficient heat exchange performance to oxidant gas while controlling the heat influence to a fuel battery cell.

  A solid oxide fuel cell device according to the present invention comprises a plurality of solid oxide fuel cell devices electrically connected to each other in a solid oxide fuel cell device which generates electric power by reaction of a fuel gas obtained by reforming raw material gas and air. A module case including a fuel cell, a top plate and a side plate, which accommodates a plurality of fuel cells, a heat insulating material provided to cover the module case, and disposed above the fuel cell in the module case; A reformer that reforms the source gas using steam to generate a fuel gas, a fuel gas supply passage that supplies the fuel gas to the plurality of fuel cells, and a plurality of fuel cells above the plurality of fuel cells in the module case; And, under the reformer, the fuel gas which did not contribute to the power generation of the plurality of fuel cells is burned, and the generated exhaust gas heats the reformer, and the inside of the heat insulating material and module The evaporator is disposed outside the case, generates steam by heat exchange with the exhaust gas, and supplies the generated steam to the reformer, which is formed between at least the top plate and side plates of the module case and the heat insulating material And the air supplied on the top plate of the module case is directed downward from above the module case along the outer surface of the side plate of the module case, and the air is supplied to the plurality of fuel cells from the lower part of the module case. The air supply passage and the top plate and side plate of the module case sandwich the air supply passage and the inside of the module case, extends along the air supply passage and guides the exhaust gas generated in the combustion section to the exhaust port for discharging. And an exhaust passage performing heat exchange between the internal air and the exhaust gas, and promoting heat exchange between the air and the exhaust gas in the air supply passage. Heat exchange promoting member is provided, the lower end of the heat exchange promoting member is extended to approximately the same height as the portion that can be exposed to radiant heat from the combustion portion of the side plate of the module case, wherein the.

  In order to prevent the deterioration of the fuel cell unit due to the temperature unevenness of the air flowing through the air passage and the exhaust gas flowing through the exhaust passage, it is conceivable to perform heat exchange above the fuel cell. However, when the fuel cell device is miniaturized, it is difficult to secure a sufficient heat exchange distance above the fuel cell.

  On the other hand, according to the present invention configured as described above, the evaporator is disposed inside the heat insulating material and outside the module case. This prevents the exhaust gas in the exhaust passage from being lowered in temperature by the evaporator, and sufficient heat exchange can be performed between the exhaust gas and air even with a short heat exchange distance.

  Further, according to the present invention, the lower end of the heat exchange promoting member extends to a height substantially equal to a portion capable of receiving the radiant heat from the combustion portion of the side plate of the module case. Thereby, the radiant heat from a combustion part is transmitted to a heat exchange promotion member via the side plate of a module case. For this reason, the air is sufficiently heated at a position above the fuel cell in the air passage, and temperature unevenness can be prevented from occurring at the height corresponding to the fuel cell in the air passage.

  Furthermore, the lower end of the heat exchange promoting member extends to a height substantially equal to a portion capable of receiving radiant heat from the combustion portion of the side plate of the module case. As a result, heat exchange from the exhaust gas to the air is promoted on the side of the combustion unit of the module case, so that the exhaust heat from the combustion unit is prevented from staying above the fuel cell, and the temperature is more reliably It is possible to suppress the occurrence of unevenness.

  Thus, according to the present invention, it is possible to improve the heat exchange performance between the exhaust gas and the air for power generation above the fuel cell, and to affect the temperature unevenness in the fuel cell. Therefore, the fuel cell device can be miniaturized.

In the present invention, preferably, the heat exchange promoting member is provided continuously from the vicinity of the air supply port provided above the module case to a position where it can receive radiant heat from the combustion unit.
According to the present invention configured as described above, the radiant heat transmitted from the combustion unit to the side plate of the module case is transmitted to the heat exchange promoting member, and further, the heat is transmitted to the vicinity of the air supply port by the heat exchange promoting member. Thus, the air can be sufficiently heated even with a short heat exchange distance.

  In the present invention, preferably, the heat storage means for storing heat is provided at the upper end portion of the fuel cell, and the lower end of the heat exchange promoting member is located at substantially the same height as the heat storage means.

  According to the present invention configured as described above, since the heat storage means receives heat from the combustion unit, direct heating of the fuel cell is prevented by the combustion unit, and temperature unevenness in the vertical direction occurs in the fuel cell. You can suppress that. Further, since the heat storage means storing heat functions as a heat source and heats the side plate of the module case, the air is sufficiently heated at a portion above the fuel cell of the air passage, and the fuel cell of the air passage is It is possible to prevent the occurrence of temperature unevenness at the height corresponding to the cell.

  According to the solid oxide fuel cell device of the present invention, the solid oxide fuel cell device performs heat exchange between the outer air passage provided along the side wall of the module case and the inner exhaust passage. In addition, while reducing the size and cost of the device, it is possible to suppress the thermal influence on the fuel cell and to ensure sufficient heat exchange performance for the oxidant gas.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram which shows the solid oxide fuel cell apparatus by one Embodiment of this invention. FIG. 1 is a front sectional view showing a fuel cell module of a solid oxide fuel cell device according to one embodiment of the present invention. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. FIG. 2 is a perspective view of the fuel cell module of the solid oxide fuel cell device according to one embodiment of the present invention with the heat insulator and the housing removed. FIG. 1 is a partial cross-sectional view showing a fuel cell unit of a solid oxide fuel cell according to one embodiment of the present invention. It is a side sectional view showing a fuel cell module for explaining a flow of gas in a fuel cell module of a solid oxide fuel cell device according to one embodiment of the present invention. FIG. 3 is a front cross-sectional view of the fuel cell module along the line III-III of FIG. 2 for explaining the flow of gas in the fuel cell module of the solid oxide fuel cell device according to one embodiment of the present invention. FIG. 1 is a partial cross-sectional view of the top of a fuel cell module of a solid oxide fuel cell device according to an embodiment of the present invention.

  Next, referring to the attached drawings, a solid oxide fuel cell device according to an embodiment of the present invention will be described.

  FIG. 1 is a whole block diagram showing a solid oxide fuel cell device (SOFC) according to an embodiment of the present invention. As shown in FIG. 1, a solid oxide fuel cell device (SOFC) 1 according to an embodiment of the present invention includes a fuel cell module 2 and an accessory unit 4.

  The fuel cell module 2 includes a housing 6, and a metal module case 8 is incorporated in the housing 6 via a heat insulating material 7. In the power generation chamber 10 which is a lower portion of the module case 8 which is a sealed space, a fuel cell and a fuel cell which perform a power generation reaction with an oxidant gas (hereinafter appropriately referred to as "power generation air" or "air") A cell assembly 12 is accommodated. The fuel cell assembly 12 is configured by connecting a plurality of fuel cell units 16 (see FIG. 5) in series. In this example, the fuel cell assembly 12 has 128 fuel cell units 16.

  A combustion chamber 18 as a combustion unit is formed above the power generation chamber 10 of the module case 8 of the fuel cell module 2, and the combustion chamber 18 is not used for a power generation reaction (does not contribute to power generation) The fuel gas and residual air are burned to generate exhaust gas (in other words, combustion gas). Furthermore, the module case 8 is covered with the heat insulating material 7 to suppress the heat in the fuel cell module 2 from being dissipated to the outside air. Further, a reformer 120 for reforming the fuel gas is disposed above the combustion chamber 18, and the heat of combustion of the remaining gas heats the reformer 120 to a temperature at which the reforming reaction is possible. There is.

  Furthermore, an evaporator 140 is provided in the heat insulating material 7 above the module case 8 in the housing 6. The evaporator 140 evaporates water to generate steam by performing heat exchange between the supplied water and the exhaust gas, and a mixed gas of the steam and the raw fuel gas (hereinafter referred to as “fuel gas”) ) Is supplied to the reformer 120 in the module case 8.

  Next, the auxiliary unit 4 stores the water obtained by condensing the water contained in the exhaust from the fuel cell module 2 and uses the filter as pure water to obtain pure water, and the water supplied from the water storage tank The water flow rate adjustment unit 28 (motor-driven "water pump" etc.) which adjusts the flow rate of this is provided. The auxiliary unit 4 also includes a gas shut-off valve 32 for shutting off the fuel supplied from the fuel supply source 30, which is a reduction in the supply of the raw material gas such as city gas, and a desulfurizer 36 for removing sulfur from the fuel gas. A fuel flow control unit 38 (motor-driven "fuel pump" etc.) for adjusting the flow rate of the fuel gas, and a valve 39 for blocking the fuel gas flowing out of the fuel flow control unit 38 at the time of power loss There is. Furthermore, the auxiliary unit 4 includes a solenoid valve 42 for blocking the air supplied from the air supply source 40, a reforming air flow rate adjustment unit 44 for adjusting the air flow rate, and a power generation air flow rate adjustment unit 45 A driven “air blower”, etc., a first heater 46 for heating the reforming air supplied to the reformer 120, and a second heater 48 for heating the power generation air supplied to the power generation chamber Have. The first heater 46 and the second heater 48 are provided to efficiently perform the temperature rise at the time of activation, but may be omitted.

  In the present embodiment, the partial oxidation reforming reaction (POX) and the steam reforming reaction (SR) are generated from the POX process in which only partial oxidation reforming reaction (POX) occurs in the reformer 120 when the apparatus is started. The SR process may be performed such that only the steam reforming reaction is performed through the ATR process in which mixed auto thermal reforming reaction (ATR) occurs, or the POX process may be omitted to perform the ATR process to the SR process. The POX process and the ATR process may be omitted, and only the SR process may be performed. In the configuration in which only the SR process is performed, the reforming air flow rate adjustment unit 44 is unnecessary.

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

  Next, the structure of a fuel cell module of a solid oxide fuel cell device according to an embodiment of the present invention will be described with reference to FIGS. 2 to 4. FIG. 2 is a side sectional view showing a fuel cell module of a solid oxide fuel cell device according to one embodiment of the present invention, and FIG. 3 is a sectional view taken along line III-III in FIG. 4 is an exploded perspective view of a module case and an air passage cover.

  As shown in FIGS. 2 and 3, the fuel cell module 2 has the fuel cell assembly 12 and the reformer 120 provided inside the module case 8 covered with the heat insulating material 7 and the module case 8. And an evaporator 140 provided in the heat insulating material 7.

  First, as shown in FIG. 4, the module case 8 includes a substantially rectangular top plate 8a, a bottom plate 8c, and a pair of opposing side plates 8b connecting sides extending in the longitudinal direction (the horizontal direction in FIG. 2). A closed side plate which closes the cylindrical body and two opposing openings at both ends in the longitudinal direction of the cylindrical body, and connects the sides of the top plate 8a and the bottom plate 8c extending in the width direction (horizontal direction in FIG. 3) It consists of 8d and 8e.

  In the module case 8, the top plate 8 a and the side plate 8 b are covered by the air passage cover 160. The air passage cover 160 has a top plate 160 a and a pair of side plates 160 b facing each other. An opening 167 for allowing the exhaust pipe 171 to penetrate is provided at a substantially central portion of the top plate 160 a. Between the top plate 160a and the top plate 8a, and between the side plate 160b and the side plate 8b, they are separated by a predetermined distance. Thus, between the outside of the module case 8 and the heat insulating material 7, specifically between the top plate 8a and the side plate 8b of the module case 8 and the top plate 160a and the side plate 160b of the air passage cover 160, Air passages 161a and 161b as oxidant gas supply passages are formed along the outer surfaces of the plate 160a and the side plate 160b (see FIG. 3).

  In the lower part of the side plate 8b of the module case 8, a plurality of through holes, ie, an outlet 8f, is provided (see FIG. 4). An air supply port 160c (see FIG. 2) communicating with the air passage 161a is formed at a substantially central portion of the top plate 160a of the air passage cover 160 on the closing side plate 8e side of the air passage cover 160. There is. The power generation air introduction pipe 74 is connected to the air supply port 160 c, and the air introduced from the power generation air introduction pipe 74 is an air passage on the top plate 8 a of the module case 8 through the flow path direction adjustment unit 164. It is supplied in 161a (refer FIG. 2, FIG. 4). Then, the power generation air is injected into the power generation chamber 10 from the blowout port 8f toward the fuel cell assembly 12 through the air passages 161a and 161b (see FIGS. 3 and 4).

  Moreover, the plate fin 162 as a heat exchange promotion member is provided in air path 161a, 161b inside (refer FIG. 3). The plate fins 162 are horizontally provided to extend in the longitudinal direction and the width direction between the top plate 8 a of the module case 8 and the top plate 160 a of the air passage cover 160, and the side plate 8 b of the module case 8. And a side plate 160 b of the air passage cover 160, and a vertical portion 162 b provided at a position above the fuel cell unit 16 so as to extend in the longitudinal direction and the vertical direction. The end of the horizontal portion 162a on the center side in the short direction extends to the vicinity of the air supply port 160c formed in the top plate 160a of the air passage cover 160.

  Further, the lower end of the vertical portion 162b extends to a height substantially equal to a portion capable of receiving radiant heat from the combustion chamber 18 of the side plate 8b of the module case 8. Specifically, the lower end of the vertical portion 162b is located in the vicinity of the upper end of the fuel cell unit 16 functioning as a heat storage unit described later, more specifically, at the height of the inner electrode terminal 86.

  The plate fin 162 is formed by bending a single plate fin near the edge of the top plate 8a, and the horizontal portion 162a and the vertical portion 162b are configured as one continuous member. In the present embodiment, although the plate fins of the horizontal portion 162a and the vertical portion 162b bend the top plate 8a, it is not always necessary to configure in this manner. For example, two plate fins may be connected by welding or the like to form the horizontal portion 162a and the vertical portion 162b, and the horizontal portion 162a and the vertical portion 162b are one continuous member so that heat can be transmitted. It should just be comprised.

  The power generation air flowing through the air passages 161a and 161b is provided inside the module case 8 inside the plate fins 162 (specifically, along the top plate 8a and the side plate 8b) when passing through the plate fins 162. The heat exchange is performed with the exhaust gas passing through the exhaust passage), and the exhaust gas is heated. From such a thing, the part in which the plate fin 162 was provided in air passage 161a, 161b functions as a heat exchanger (heat exchange part). In addition, the part in which the horizontal part 162a of the plate fin 162 was provided comprises the main heat exchanger part, and the part in which the perpendicular part 162b of the plate fin 162 is provided comprises the heat exchanger part which follows.

  Next, the evaporator 140 is fixed so as to extend in the horizontal direction on the top plate 8 a of the module case 8. In addition, a portion 7a of the heat insulating material 7 is disposed between the evaporator 140 and the module case 8 so as to fill these gaps (see FIGS. 2 and 3).

  Specifically, the evaporator 140 has a fuel supply pipe 63 for supplying water and raw fuel gas (which may include reforming air) on one side end side in the longitudinal direction (left and right direction in FIG. 2) An exhaust gas discharge pipe 82 (see FIG. 3) for exhausting the exhaust gas is connected, and an upper end portion of the exhaust pipe 171 is connected to the other end side in the longitudinal direction. The exhaust pipe 171 extends downward through the opening 167 formed in the top plate 160 a of the air passage cover 160, and is connected to the exhaust port 111 formed on the top plate 8 a of the module case 8. The exhaust port 111 is an opening for discharging the exhaust gas generated in the combustion chamber 18 in the module case 8 to the outside of the module case 8, and substantially at the center of the top plate 8 a of the module case 8 in a substantially rectangular shape in top view. It is formed.

  Moreover, the evaporator 140 has the substantially rectangular evaporator case 141 by top view, as shown in FIG.2 and FIG.3. The evaporator case 141 is formed by joining two low-profile bottomed rectangular cylindrical upper and lower cases 142 and 143 with the intermediate plate 144 interposed therebetween.

  Therefore, the evaporator case 141 has a two-layered structure in the vertical direction, and an exhaust passage portion 140A through which exhaust gas supplied from the exhaust pipe 171 passes is formed in the lower layer portion, and fuel is formed in the upper layer portion. An evaporator 140B for evaporating water supplied from the supply pipe 63 to generate steam, and a mixer 140C for mixing the water vapor generated by the evaporator 140B with the raw fuel gas supplied from the fuel supply pipe 63 are provided. It is done.

  As shown in FIG.2 and FIG.3, the evaporation part 140B and the mixing part 140C are formed in the space which divided the evaporator 140 by the partition plate 145 in which the several communicating hole (slit) 145a was formed. In addition, alumina balls (not shown) are filled in the evaporation portion 140B.

  The exhaust passage portion 140A is also divided into three spaces from the upstream side to the downstream side of the exhaust gas by two partition plates 146 and 147 similarly having a plurality of communication holes. Then, a combustion catalyst (not shown) is filled in the second space. That is, the evaporator 140 of the present embodiment includes the combustion catalyst in the lower layer structure of the two-layered structure in the vertical direction.

  In such an evaporator 140, heat exchange is performed between the water in the evaporation section 140B and the exhaust gas passing through the exhaust passage section 140A, and the water in the evaporation section 140B is evaporated by the heat of the exhaust gas. Water vapor will be generated. Further, heat exchange is performed between the mixed gas in the mixing portion 140C and the exhaust gas passing through the exhaust passage portion 140A, and the temperature of the mixed gas is raised by the heat of the exhaust gas.

  Furthermore, as shown in FIG. 2, a mixed gas supply pipe 112 for supplying mixed gas to the reformer 120 is connected to the mixing section 140C. The mixed gas supply pipe 112 is disposed so as to pass through the inside of the exhaust pipe 171, one end thereof is connected to the opening 144 a formed in the intermediate plate 144, and the other end is formed on the top surface of the reformer 120. It is connected to the mixed gas supply port 120a. The mixed gas supply pipe 112 extends vertically downward to the inside of the module case 8 by passing through the exhaust passage portion 140A and the exhaust pipe 171, where it is bent approximately 90 ° and extends horizontally along the top plate 8a. , And is bent downward approximately 90 degrees and connected to the reformer 120.

  Next, the reformer 120 is disposed to extend horizontally along the longitudinal direction of the module case 8 above the combustion chamber 18, and the exhaust gas guiding member 130 is interposed between the reformer 120 and the top plate 8 a of the module case 8. It is being fixed to top plate 8a in the state where it is separated by a predetermined distance via. The reformer 120 is an annular structure having a substantially rectangular outer shape in top view, but has a through hole 120b formed at the center, and has a housing in which an upper case 121 and a lower case 122 are joined. ing. The through hole 120b is positioned so as to overlap with the exhaust port 111 formed in the top plate 8a in a top view, and preferably, the exhaust port 111 is formed at the center position of the through hole 120b.

  The mixed gas supply pipe 112 is connected to the mixed gas supply port 120 a provided in the upper case 121 at one end side (the closing side plate 8 e side of the module case 8) of the reformer 120 in the longitudinal direction (the other side ( In the closed side plate 8 d side, the fuel gas supply pipe 64 is connected to the lower case 122, and the hydrodesulfurizer hydrogen extraction pipe 65 extending to the desulfurizer 36 is connected to the upper case 121. Therefore, the reformer 120 receives the mixed gas (that is, the raw fuel gas (which may include reforming air) mixed with the steam) from the mixed gas supply pipe 112, and reforms the mixed gas internally, The reformed gas (i.e., the fuel gas) is discharged from the fuel gas supply pipe 64 and the hydrogen removal pipe 65 for the hydrodesulfurizer.

  The reformer 120 is configured such that the internal space thereof is divided into three spaces by two partition plates 123a and 123b, so that a mixed gas receiving unit 120A that receives mixed gas from the mixed gas supply pipe 112 in the reformer 120. , A reforming unit 120B filled with a reforming catalyst (not shown) for reforming the mixed gas, and a gas discharging unit 120C for discharging the gas that has passed through the reforming unit 120B. (See Figure 2). The reforming unit 120B is a space sandwiched by the partition plates 123a and 123b, and the reforming catalyst is held in this space. The mixed gas and the reformed fuel gas are movable through a plurality of communication holes (slits) provided in the partition plates 123a and 123b. Further, as the reforming catalyst, a catalyst provided with nickel on the surface of alumina spheres or a catalyst provided with ruthenium on the surface of alumina spheres may be suitably used.

  The mixed gas supplied from the evaporator 140 through the mixed gas supply pipe 112 is ejected through the mixed gas supply port 120a to the mixed gas receiving unit 120A. The mixed gas is expanded in the mixed gas receiving unit 120A, the ejection speed is reduced, and the mixed gas passes through the partition plate 123a and is supplied to the reforming unit 120B.

  In the reforming unit 120B, the mixed gas moving at a low speed is reformed into a fuel gas by the reforming catalyst, and the fuel gas passes through the partition plate 123b and is supplied to the gas discharge unit 120C.

  In the gas discharge unit 120C, the fuel gas is discharged to the fuel gas supply pipe 64 and the hydrogen removal pipe 65 for a hydrodesulfurizer.

  A fuel gas supply pipe 64 as a fuel gas supply passage extends downward along the closing side plate 8d in the module case 8, is bent approximately 90 ° in the vicinity of the bottom plate 8c, and extends in the horizontal direction. , And further extend horizontally in the manifold 66 to the vicinity of the opposite closing side plate 8e. A plurality of fuel supply holes 64 b are formed on the lower surface of the horizontal portion 64 a of the fuel gas supply pipe 64, and the fuel gas is supplied into the manifold 66 from the fuel supply holes 64 b. A lower support plate 68 having a through hole for supporting the fuel cell unit 16 is attached above the manifold 66, and the fuel gas in the manifold 66 is supplied into the fuel cell unit 16. Ru. Further, an igniter 83 for starting the combustion of the fuel gas and the air is provided in the combustion chamber 18.

  The exhaust gas guiding member 130 is arranged to extend horizontally along the longitudinal direction of the module case 8 between the reformer 120 and the top plate 8 a. The exhaust gas guiding member 130 includes a lower guiding plate 131 and an upper guiding plate 132 which are separated by a predetermined distance in the vertical direction, and connecting plates 133 and 134 to which both longitudinal sides thereof are attached (FIG. 2 , See Figure 3). The upper guide plate 132 is bent downward at both ends in the width direction, and is connected to the lower guide plate 131. The connection plates 133 and 134 are connected at their upper ends to the top plate 8a and at their lower ends to the reformer 120, thereby fixing the exhaust gas guiding member 130 and the reformer 120 to the top plate 8a. ing.

  The lower guide plate 131 is formed with a convex stepped portion 131a in which a central portion in the width direction (left and right direction in FIG. 3) protrudes downward. On the other hand, in the upper guide plate 132, similarly to the lower guide plate 131, the recess 132a is formed such that the central portion in the width direction is concaved downward. The convex stepped portion 131a and the concave portion 132a extend in the longitudinal direction in parallel with each other in the vertical direction. The mixed gas supply pipe 112 extends horizontally in the recess 132a in the module case 8 and then bends downward near the closing side plate 8e to penetrate the upper induction plate 132 and the lower induction plate 131, It is connected to the reformer 120.

  In the exhaust gas guiding member 130, a gas reservoir 135 which is an internal space functioning as a heat insulating layer is formed by the upper induction plate 132, the lower induction plate 131, and the connection plates 133 and 134. The gas reservoir 135 is in fluid communication with the combustion chamber 18. That is, the upper guide plate 132, the lower guide plate 131, and the connection plates 133 and 134 are connected to form a predetermined gap, and are not connected in an airtight manner. While it is possible for exhaust gas from the combustion chamber 18 to flow into the gas reservoir 135 during operation and air from the outside to flow during shutdown, the movement of gas between the inside and the outside of the gas reservoir 135 as a whole Is loose.

  Upper induction plate 132 is disposed at a predetermined vertical distance from top plate 8a, and exhaust air extending in the horizontal direction along the longitudinal direction and width direction between upper induction plate 132 and top plate 8a. A passage 172 is formed. The exhaust passage 172 is juxtaposed with the air passage 161a with the top plate 8a of the module case 8 interposed therebetween. In the exhaust passage 172, plate fins 175 similar to the plate fins 162 in the air passages 161a and 161b are provided. It is arranged. The plate fins 175 are provided at substantially the same locations as the horizontal portions 162a of the plate fins 162 in top view, and are opposed in the vertical direction with the top plate 8a interposed therebetween. In the portions of the air passage 161a and the exhaust passage 172 where the plate fins 162 and 175 are provided, efficient heat exchange is performed between the power generation air flowing through the air passage 161a and the exhaust gas flowing through the exhaust passage 172. Thus, the temperature of the power generation air is raised by the heat of the exhaust gas.

  Further, the reformer 120 is disposed at a predetermined horizontal distance from the side plate 8b of the module case 8, and the exhaust gas is allowed to pass upward from below between the reformer 120 and the side plate 8b. An exhaust passage 173 is formed. The exhaust gas guiding member 130 is also disposed at a predetermined horizontal distance from the side plate 8b, and the exhaust passage 173 extends to the top plate 8a including the passage between the exhaust gas guiding member 130 and the side plate 8b. ing. The exhaust passage 173 communicates with the exhaust passage 172 via an exhaust gas inlet 172a located at a corner between the top plate 8a and the side plate 8b. The exhaust gas inlet 172 a extends in the longitudinal direction in the module case 8.

  Furthermore, the lower guide plate 131 is disposed at a predetermined vertical distance from the top surface of the upper case 121 of the reformer 120, and between the lower guide plate 131 and the upper case 121, and the reformer The through hole 120b of 120 forms an exhaust passage 174 for passing the exhaust gas that has passed through the through hole 120b from the lower side to the upper side. The exhaust passage 174 joins the exhaust passage 173 above the reformer 120.

Next, the fuel cell unit 16 will be described with reference to FIG.
FIG. 5 is a partial cross-sectional view showing a fuel cell unit of a solid oxide fuel cell according to one embodiment of the present invention.
As shown in FIG. 5, the fuel cell unit 16 includes a fuel cell 84 and an inner electrode terminal 86 which is a cap connected to both ends of the fuel cell 84.

  The fuel cell 84 is a tubular structure extending in the vertical direction, and has a cylindrical inner electrode layer 90 forming a fuel gas channel 88 therein, a cylindrical outer electrode layer 92, an inner electrode layer 90, and an outer side. And an electrolyte layer 94 between the electrode layer 92 and the electrode layer 92. The inner electrode layer 90 is a fuel electrode through which the fuel gas passes and is a (-) electrode, while the outer electrode layer 92 is an air electrode in contact with air and is a (+) electrode.

  Since the inner electrode terminals 86 attached to the upper end side and the lower end side of the fuel cell 84 have the same structure, here, the inner electrode terminal 86 attached to the upper end side will be specifically described. An upper portion 90 a of the inner electrode layer 90 includes an outer circumferential surface 90 b exposed to the electrolyte layer 94, the outer electrode layer 92, and an upper end surface 90 c. The inner electrode terminal 86 is connected to the outer peripheral surface 90 b of the inner electrode layer 90 via the conductive seal material 96, and is in direct contact with the upper end surface 90 c of the inner electrode layer 90 to connect with the inner electrode layer 90. It is electrically connected. At a central portion of the inner electrode terminal 86, a fuel gas channel thin tube 98 communicating with the fuel gas channel 88 of the inner electrode layer 90 is formed.

  The fuel gas flow path narrow tube 98 is an elongated thin tube extending 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 fuel gas flowing from the manifold 66 (see FIG. 2) through the fuel gas flow passage narrow tube 98 of the lower inner electrode terminal 86 into the fuel gas flow passage 88. Do. Therefore, the fuel gas flow passage thin tube 98 of the lower side inner electrode terminal 86 acts as an inflow side flow passage resistance portion, and the flow passage resistance thereof is set to a predetermined value. Further, a predetermined pressure loss also occurs in the flow of the fuel gas flowing out of the fuel gas flow passage 88 through the fuel gas flow passage narrow tube 98 of the upper inner electrode terminal 86 to the combustion chamber 18 (see FIG. 2). Therefore, the fuel gas flow passage thin tube 98 of the upper side inner electrode terminal 86 acts as an outflow side flow passage resistance portion, and the flow passage resistance thereof is set to a predetermined value.

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

  The electrolyte layer 94 is, 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 of at least one of the

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

  At least the upper inner electrode terminal 86 is formed of a metal having a large heat capacity and a high heat storage property, and functions as a heat storage means. The heat generated in the combustion chamber 18 above the fuel cell unit 16 is stored in the upper inner electrode terminal 86, whereby direct transfer of the heat from the combustion chamber 18 to the fuel cell 84 can be suppressed. Further, the inner electrode terminal 86 thus stored heat functions as a heat source, and releases the stored heat to the surroundings.

  The fuel cell assembly 12 has an inner electrode terminal 86 attached to an inner electrode layer 90 which is a fuel electrode of each fuel cell unit 16, and an outer electrode layer 92 which is an air electrode of another fuel cell unit 16. By being electrically connected to the outer peripheral surface, all of the 128 fuel cell units 16 are connected in series.

Next, gas and heat flows in a fuel cell module of a solid oxide fuel cell device according to an embodiment of the present invention will be described with reference to FIGS. 6 to 8.
6 is a side sectional view showing a fuel cell module of a solid oxide fuel cell device according to an embodiment of the present invention, similar to FIG. 2, and FIG. 7 is a view similar to FIG. FIG. 7 is a cross-sectional view taken along the line III. FIG. 8 is a partial cross-sectional view of the top of a fuel cell module of a solid oxide fuel cell device according to an embodiment of the present invention.
6 and 7 are diagrams newly added with arrows indicating the flow of gas in FIGS. 2 and 3, respectively, and for convenience of explanation, they are illustrated with the heat insulating material 7 removed. . In the figure, solid arrows indicate the flow of fuel gas, broken arrows indicate the flow of power generation air, and dashed dotted arrows indicate the flow of exhaust gas.

  As shown in FIG. 6, water and raw fuel gas (fuel gas) are supplied from the fuel supply pipe 63 connected to one end side in the longitudinal direction of the evaporator 140 into the evaporator 140 B provided in the upper layer of the evaporator 140. Supplied. The water supplied to the evaporation unit 140B is heated by the exhaust gas flowing in the exhaust passage portion 140A provided in the lower layer of the evaporator 140 and becomes water vapor. The water vapor and the raw fuel gas supplied from the fuel supply pipe 63 flow in the downstream direction in the evaporator 140B, and are mixed in the mixer 140C. The mixed gas in the mixing section 140C is heated by the exhaust gas flowing through the lower exhaust passage section 140A.

  The mixed gas (fuel gas) formed in the mixing unit 140C is supplied to the reformer 120 in the module case 8 through the mixed gas supply pipe 112. The mixed gas supply pipe 112 sequentially passes through the exhaust passage portion 140A, the exhaust pipe 171, and the exhaust passage 172. Therefore, the mixed gas in the mixed gas supply pipe 112 is further heated by the exhaust gas flowing through these passages. Ru.

  The mixed gas flows into the mixed gas receiving unit 120A in the reformer 120, and from there flows through the partition plate 123a and flows into the reforming unit 120B. The mixed gas is reformed in the reforming unit 120B to be a fuel gas. The fuel gas thus generated passes through the partition plate 123b and flows into the gas discharge portion 120C.

  Further, the fuel gas branches from the gas discharge unit 120C into the fuel gas supply pipe 64 and the hydrogen removal pipe 65 for the hydrodesulfurizer. Then, the fuel gas flowing into the fuel gas supply pipe 64 is supplied into the manifold 66 from the fuel supply holes 64 b provided in the horizontal portion 64 a of the fuel gas supply pipe 64, and is supplied from the manifold 66 into each fuel cell unit 16. Supplied.

  Also, as shown in FIGS. 6 and 7, the power generation air is supplied from the power generation air introduction pipe 74 to the air passage 161a. When the power generation air passes through the plate fins 162 in the air passages 161a and 161b, the air for power generation passes between the exhaust passages 172 and 173 formed in the module case 8 below the plate fins 162. Heat exchange and heat up. In particular, since the plate fins 175 are provided in the exhaust passage 172 corresponding to the plate fins 162 of the air passage 161 a, the power generation air is connected to the exhaust gas through the plate fins 162 and the plate fins 175. Perform more efficient heat exchange.

  Further, as the off gas is burned in the combustion chamber 18, a portion of the side plate 8b of the module case 8 above the upper end portion of the fuel cell unit 16 receives radiant heat and is heated. Then, by heating the side plate 8b of the module case 8, this heat is transmitted to the vertical portion 162b of the plate fin 162 in the air passage 161b. Furthermore, the heat transmitted to the vertical portion 162b of the plate fin 162 is transmitted to the horizontal portion 162a. Therefore, the air is efficiently heated also in the portion of the air passage 161 b above the upper end portion of the fuel cell unit 16. Thereafter, the power generation air is injected into the power generation chamber 10 toward the fuel cell assembly 12 from the plurality of outlets 8 f provided in the lower part of the side plate 8 b of the module case 8.

  In the present embodiment, since the exhaust passage is not formed at the side portion of the fuel cell assembly 12, heat exchange between the power generation air and the exhaust gas is suppressed at this portion. Therefore, in the side portion of the fuel cell assembly 12, temperature unevenness in the vertical direction is less likely to occur in the power generation air in the air passage 161b.

  Further, as shown in FIG. 7, the fuel gas not used for power generation in the power generation chamber 10 is burned in the combustion chamber 18 to become exhaust gas (combustion gas), and ascends in the module case 8. Specifically, the exhaust gas is branched into the exhaust passage 173 and the exhaust passage 174, and between the outer surface of the reformer 120 and the side plate 8 b of the module case 8 and the through hole 120 b of the reformer 120. And between the reformer 120 and the exhaust gas guiding member 130. At this time, the exhaust gas passing through the exhaust passage 174 is divided in two in the width direction by the convex step 131a disposed above the through hole 120b of the reformer 120, and does not stay in the lower portion of the exhaust gas guiding member 130. The exhaust gas is directed toward the exhaust passage 173 and quickly joins the exhaust gas flowing through the exhaust passage 173.

  Further, as shown in FIG. 9, radiant heat is generated by burning the fuel gas not used for power generation in the power generation chamber 10 in the combustion chamber 18. The radiant heat is mainly a portion above the upper end of the fuel cell unit 16 (inner electrode terminal 86) and the upper end of the fuel cell unit 16 of the side plate 8b of the module case 8 as shown by the arrow A. Are radiated, and these parts are heated by radiant heat.

  The inner electrode terminal 86 of the fuel cell unit 16 of the side plate 8b of the module case 8 is made of a material having a high heat storage property, so that the heat generated in the combustion chamber 18 is stored. Then, the inner electrode terminal 86 functions as a heat source when heat is stored, and as shown by the arrow B, heats the vertical portion 162b of the plate fin 162 via the side plate 8b of the module case 8. When the vertical portion 162b is heated, the heat is transmitted to a portion in the vicinity of the air supply port 160c of the horizontal portion 162a as shown by the arrow C. Therefore, the fuel cell is connected to the air passage 160a. Heat exchange is efficiently performed in a portion above the upper end of the unit 16.

  Thereafter, the exhaust gas flows into the exhaust passage 172 from the exhaust gas inlet 172a. In the exhaust passage 172, the exhaust gas flows in the horizontal direction in the exhaust passage 172 and flows out from the exhaust port 111 formed at the center of the top plate 8 a of the module case 8.

  When the exhaust gas flows upward through the exhaust passage 173, heat exchange is performed between the power generation air and the exhaust gas through the vertical portion 162b of the plate fin 162 provided in the air passage 161b. It will be. Further, when the exhaust gas flows in the exhaust passage 172 in the horizontal direction, the plate fins 175 provided in the exhaust passage 172 and the plate fins 162 provided in the air passage 161 a corresponding to the plate fins 175. The efficient heat exchange is performed between the power generation air and the exhaust gas via the horizontal portion 162a of the Thus, the power generation air is heated by the heat of the exhaust gas.

  Then, the exhaust gas flowing out of the exhaust port 111 passes through the exhaust pipe 171 provided outside the module case 8 and flows into the exhaust passage portion 140A of the evaporator 140, passes through the exhaust passage portion 140A, and then evaporates. The exhaust gas is discharged from the fuel container 140 into the exhaust gas discharge pipe 82. As described above, when the exhaust gas flows through the exhaust passage portion 140A of the evaporator 140, the exhaust gas exchanges heat with the mixed gas in the mixing portion 140C of the evaporator 140 and the water in the evaporation portion 140B.

According to the solid oxide fuel cell device 1 according to the present embodiment, the following effects are achieved.
In the present embodiment, the evaporator 140 is disposed inside the heat insulating material 7 and outside the module case 8. This prevents the exhaust gas in the exhaust passages 172, 173 from being lowered in temperature by the evaporator 140, and the exhaust gas in the exhaust passages 172, 173 and the air in the air passage 161, even if the heat exchange distance is short. Sufficient heat exchange can be performed between the

  Further, in the present embodiment, the lower end of the vertical portion 162 b of the plate fin 162 extends to a height substantially equal to the portion capable of receiving the radiant heat from the combustion chamber 18 of the side plate 8 b of the module case 8. Thus, the radiant heat from the combustion chamber 18 is transmitted to the vertical portion 162 b of the plate fin 162 through the side plate 8 b of the module case 8. For this reason, the air is sufficiently heated above the fuel cells 84 of the air passages 161a and 161b, and temperature unevenness occurs at the height corresponding to the fuel cells 84 of the air passages 161a and 161b. Can be prevented.

  Further, for example, when the lower end of the vertical portion 162b of the plate fin 162 terminates at substantially the same height as the reformer 120, exhaust is generated at a portion corresponding to the side of the combustion chamber 18 of the side plate 8b of the module case 8 Heat exchange efficiency between gas and air is reduced. As described above, when the heat exchange efficiency at the portion corresponding to the side of the combustion chamber 18 is lowered, the heat generated in the combustion chamber 18 is retained above the fuel cell unit 16.

  On the other hand, in the present embodiment, the lower end of the vertical portion 162 b of the plate fin 162 extends to a height substantially equal to the portion of the side plate 8 b of the module case 8 that can receive the radiant heat from the combustion chamber 18. As a result, the exchange of exhaust gas to air is promoted on the side of the combustion chamber 18 of the module case 8, so that the exhaust heat from the combustion chamber 18 is prevented from staying above the fuel cell unit 16. It is possible to reliably suppress the occurrence of temperature unevenness.

  Thus, according to the present embodiment, the heat exchange performance between the exhaust gas and the air above the fuel cell 84 can be improved, and the fuel cell 84 is affected by the temperature unevenness. Therefore, the fuel cell device 1 can be miniaturized.

  Further, in the present embodiment, the plate fin 162 is configured such that the horizontal portion 162a and the vertical portion 162b are integrally formed, from the vicinity of the air supply port 160c to a position where radiation heat from the combustion chamber 18 can be received. It is provided. Thereby, the radiant heat transmitted from the combustion chamber 18 to the side plate 8b of the module case 8 is transmitted to the vertical portion 162b of the plate fin 162, and further, the heat is transmitted to the vicinity of the air supply port 162c by the plate fin 162. Even with a short heat exchange distance, the air can be heated sufficiently.

  In the present embodiment, the upper end portion of the fuel cell 84 is provided with the inner electrode terminal 86 formed of a metal having a large heat capacity and high heat storage property, and the lower end of the vertical portion 162b of the plate fin 162 is the inner electrode terminal It is located at about the same height as 86. Thereby, since the inner electrode terminal 86 receives the heat from the combustion chamber 18, the fuel cell 84 is prevented from being directly heated by the combustion chamber 18, and the generation of the temperature unevenness in the vertical direction in the fuel cell 84 is suppressed. it can. Further, the inner electrode terminal 86 storing heat functions as a heat source, and heats the vertical portion 162b of the plate fin 162 via the side plate 8b of the module case 8. Therefore, a portion of the air passage 161b above the fuel cell 84 Thus, the air is sufficiently heated, and temperature unevenness can be prevented from occurring at the height of the air passage 161 b corresponding to the fuel cell 84.

DESCRIPTION OF SYMBOLS 1 solid oxide fuel cell device 2 fuel cell module 4 accessory unit 6 housing 7 heat insulating material 8 module case 8 a top plate 8 b side plate 8 c bottom plate 8 d closing side plate 8 e closing side plate 8 f outlet 10 power generation chamber 12 fuel cell assembly 16 Fuel cell unit 18 combustion chamber 24 water supply source 26 pure water tank 28 water flow adjustment unit 30 fuel supply source 32 gas shut-off valve 36 desulfurizer 38 fuel flow adjustment unit 39 valve 40 air supply source 42 solenoid valve 44 reforming air Flow adjustment unit 45 Power generation air flow adjustment unit 46 First heater 48 Second heater 50 Water heater 52 Control box 54 Inverter 63 Fuel supply piping 64 Fuel gas supply pipe 64a Horizontal part 64b Fuel supply hole 65 Hydrogen removal for hydrodesulfurizer Tube 66 Manifold 68 Lower support plate 74 Air introduction tube 8 for power generation Exhaust gas discharge pipe 83 Ignition device 84 Fuel battery cell 86 Inner electrode terminal 88 Fuel gas flow path 90 Inner electrode layer 92 Outer electrode layer 94 Electrolyte layer 96 Seal material 98 Fuel gas flow path thin tube 111 Exhaust port 112 Mixed gas supply pipe 120 Gasifier 120A Mixed gas receiving unit 120B Reforming unit 120C Gas discharging unit 120a Mixed gas supply port 120b Through hole 121 Upper case 122 Lower case 123a Partition plate 123b Partition plate 130 Exhaust gas guiding member 131 Lower guide plate 131a Convex step 132 upper induction plate 132a recessed portion 133 connection plate 134 connection plate 135 gas reservoir 140 evaporator 140A exhaust passage portion 140B evaporation portion 140C mixing portion 141 evaporator case 142 upper case 143 lower case 144 intermediate plate 144a opening 145 partition plate 146 partition plate 160 air passage force Bar 160a Top plate 160b Side plate 160c Air supply port 161a Air passage 161b Air passage 162 Plate fin 162a Horizontal portion 162b Vertical portion 163 Plate fin 164 Flow direction adjustment portion 167 Opening 171 Exhaust pipe 172 Exhaust passage 173 Exhaust passage 174 Exhaust passage 175 Plate fin

Claims (3)

In a solid oxide fuel cell device that generates electric power by the reaction of a fuel gas obtained by reforming a raw material gas and air,
A plurality of fuel cells electrically connected to one another;
A module case that includes a top plate and a side plate and accommodates the plurality of fuel cells;
A heat insulating material provided to cover the module case,
A reformer disposed above the fuel cell in the module case and reforming feed gas using steam to generate the fuel gas;
A fuel gas supply passage for supplying the fuel gas to the plurality of fuel cells;
The fuel gas not contributing to the power generation of the plurality of fuel cells is burned above the plurality of fuel cells in the module case and below the reformer, and the reformed gas is generated by the generated exhaust gas. A combustion unit that heats the stove,
An evaporator disposed inside the heat insulating material and outside the module case, generating steam by heat exchange with exhaust gas, and supplying the generated steam to the reformer;
The air formed between at least the top plate and the side plate of the module case and the heat insulating material and supplied on the top plate of the module case along the outer surface of the side plate of the module case from above the module case An air supply passage which guides downward and supplies air from the lower portion of the module case to the plurality of fuel cells;
It extends along the air supply passage, sandwiching the top plate and the side plate of the module case inside the module case, and guides the exhaust gas generated in the combustion section to the exhaust port for discharging, and the air supply passage And an exhaust passage performing heat exchange between the internal air and the exhaust gas,
In the air supply passage, a heat exchange promoting member is provided which promotes heat exchange between the air and the exhaust gas.
The solid oxide fuel cell device according to claim 1, wherein a lower end of the heat exchange promoting member extends to a height substantially equal to a portion capable of receiving radiant heat from the combustion portion of the side plate of the module case.   The solid according to claim 1, wherein the heat exchange promoting member is provided continuously from the vicinity of an air supply port provided above the module case to a position capable of receiving radiant heat from the combustion unit. Oxide fuel cell device.   A heat storage unit for storing heat is provided at an upper end portion of a fuel battery cell constituting the fuel battery cell, and a lower end of the heat exchange promoting member is positioned at substantially the same height as the heat storage unit. The solid oxide fuel cell device according to claim 1.

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