JP2016177881A - Fuel cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell module capable of enhancing the generation efficiency by improving the heat utilization efficiency in an insulation housing, thereby enhancing the reforming rate in the reformer.SOLUTION: A fuel cell module 10 has a configuration for housing a fuel cell stack 14 and a reformer 22, for producing a reformed fuel by steam-reforming reaction by the reforming steam and raw fuel gas, and supplying the reformed fuel thus produced to the fuel cell stack 14, in a heat insulation housing 16. In this fuel cell module 10, the reformer 22 is arranged in the vertical direction in the heat insulation housing 16, and has a raw fuel gas inlet port 23 at an upper part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fuel cell module in which a fuel cell stack and a reformer that generates reformed fuel are housed in a heat insulating casing.

  In a high-temperature fuel cell that reacts at about 600 ° C. to 1000 ° C., such as a solid oxide fuel cell (SOFC) or a molten carbonate fuel cell (MCFC), a fuel cell stack is provided in the inner space of the heat insulating housing. It is housed to form a high-temperature fuel cell module.

  For example, Patent Document 1 discloses a configuration in which a reformer is disposed in the vicinity of the fuel cell stack so that the radiant heat from the fuel cell stack can be directly received by the reformer, and these are housed in a heat insulating casing. Has been. In this configuration, reforming is performed while flowing the raw fuel gas from the bottom of the reformer toward the top of the reformer, and the generated hydrogen is supplied to the fuel electrode of the fuel cell stack.

JP 2006-86053 A

  In the case where the fuel cell stack and the reformer are housed in the heat insulating casing as in the configuration of Patent Document 1, heat is generated at the top in the internal space (power generation reaction chamber) of the heat insulating casing, and relative to the bottom. Therefore, the temperature may be lowered.

  By the way, the reforming reaction in the reformer is an endothermic reaction, and a catalyst such as nickel or ruthenium is used as the catalyst. Requires great heat. Therefore, in the configuration of Patent Document 1, since the reaction part outlet where the endothermic reaction becomes relatively small is arranged at the upper part of the power generation reaction chamber, it is not possible to efficiently use the heat of the upper part where heat is easily generated. For this reason, a reduction in the reforming rate in the reformer and an increase in the methane concentration cause a reduction in power generation efficiency of the entire fuel cell module.

  The present invention has been made in consideration of the above-described conventional problems, and can improve the heat utilization efficiency in the heat insulating casing to improve the reforming rate in the reformer and improve the power generation efficiency. An object is to provide a battery module.

  The fuel cell module according to the present invention generates a reformed fuel by a steam reforming reaction using a fuel cell stack, reforming steam and raw fuel gas, and supplies the generated reformed fuel to the fuel cell stack. The reformer is disposed along the vertical direction in the heat insulation casing and has an inlet for the raw fuel gas at the top. Features.

  According to such a configuration, the reformer is arranged along the vertical direction in the heat insulating casing, and the inlet of the raw fuel gas is provided at the upper part of the reformer. For this reason, the heat concentrated in the upper part in the heat insulating housing can be applied to the inlet side that requires the greatest heat in the reformer. Therefore, the heat utilization efficiency in the heat insulating casing can be increased, the reforming rate in the reformer can be improved, and the power generation efficiency in the entire fuel cell module can be improved.

  When the reformer is disposed opposite to the side surface of the fuel cell stack, convective heat transfer of high-temperature combustion exhaust gas and radiant heat from the fuel cell stack operating at high temperature can be efficiently recovered by the reformer. it can.

  A reforming water evaporator that generates the reforming water vapor may be provided, and the reforming water evaporator may be installed above the fuel cell stack in the heat insulating casing. If it does so, the water vapor | steam for a reforming can be produced | generated efficiently using the heat which generate | occur | produces and raises in a heat insulation housing | casing. In addition, since the reforming water evaporator is installed above the fuel cell stack and the reformer inlet is installed at the top, the flow of the raw fuel gas and reforming steam between the two becomes smooth.

  The reformer may have a flat plate structure having a flat plate reforming reaction section or a tubular structure having a tubular reforming reaction section.

  A plurality of the fuel cell stacks may be arranged, and the reformer may be configured to face the side surface of each fuel cell stack.

  When a plurality of the fuel cell stacks are arranged and the inner diameter and the pipe length of each pipe from the fuel gas outlet of the reformer to each fuel cell stack are set to be the same, supply from the reformer to each fuel cell stack Gas can be equally distributed, the performance of each fuel cell stack can be balanced, and stable system efficiency can be obtained.

  A support base for supporting the reformer is provided, and the upper part of the support base is provided with a key claw structure that engages with the upper edge of the reformer to prevent the reformer from falling or falling off. be able to.

  ADVANTAGE OF THE INVENTION According to this invention, the heat utilization efficiency in a heat insulation housing | casing can be improved, the reforming rate in a reformer can be improved, and the electric power generation efficiency in the whole fuel cell module can be improved.

FIG. 1 is a block diagram illustrating a configuration of a power generation device including a fuel cell module according to an embodiment of the present invention. FIG. 2 is a perspective view showing a configuration example of a fuel cell module according to an embodiment of the present invention. FIG. 3 is a configuration diagram illustrating an example of a support base for supporting the reformer in the heat insulating housing. FIG. 3 (A) is a side view, FIG. 3 (B) is a rear view, and FIG. C) is a bottom view. FIG. 4 is a perspective view showing a reformer according to a modification. FIG. 5 shows the case where the raw fuel gas is flowed from the upper part to the lower part using the reformer of the present embodiment, and the raw fuel gas is flowed from the lower part to the upper part with the same equipment configuration as this reformer. It is the graph which compared the reforming performance with respect to the temperature of the reformer in the case where it did.

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

  First, the overall configuration of the power generation device 12 including the fuel cell module 10 will be described with reference to FIG. FIG. 1 is a block diagram illustrating a configuration of a power generation device 12 including a fuel cell module 10 according to an embodiment of the present invention.

  As shown in FIG. 1, the power generation device 12 includes a fuel cell module 10 in which a fuel cell stack 14 is provided inside a heat insulating housing 16, fuel supply lines LF1 to LF3 that supply fuel and air to the fuel cell module 10, and Air supply lines LA1 and LA2, a hot water heat exchanger 18 that produces hot water using exhaust heat from the fuel cell module 10, and water for generating reforming steam used in the fuel cell module 10 are stored. It is comprised as a cogeneration system provided with the condensed water tank 20 to do.

  The fuel cell module 10 includes a fuel cell stack 14, a reformer 22, an air preheater 24, and a reformed water evaporator 26, and includes a heat insulating casing 16 that defines a heat insulating member in a box shape. It is installed inside (high temperature chamber). A general heat insulating material such as glass wool may be used as the heat insulating member. However, the fuel cell module 10 can be configured more compactly by using a board-shaped high-performance heat insulating material.

  The fuel cell stack 14 has a known configuration in which a plurality of rectangular flat power generation cells that generate power by reacting fuel introduced from the fuel supply line LF3 and air introduced from the air supply line LA2 are stacked. In the case of the present embodiment, the fuel cell stack 14 is constituted by a solid oxide fuel cell (SOFC) in which ion conductive ceramics are interposed as an electrolyte between a fuel electrode (anode) 14a and an air electrode (cathode) 14b. doing. When the solid oxide fuel cell is configured by a flat stack stack, the fuel cell stack 14 can be configured compactly, and the power generation output per volume can be increased. Other high-temperature fuel cells such as a molten carbonate fuel cell (MCFC) may be used as the fuel cell stack 14. On the side of the fuel cell stack 14, a heater 28 for raising the temperature is installed.

  The raw fuel gas (for example, hydrocarbon fuel such as natural gas, LPG or city gas) from the fuel supply line LF1 becomes a reformed fuel containing hydrogen and carbon monoxide via the desulfurizer 30 and the reformer 22. The fuel supply line LF3 is introduced into the fuel electrode 14a.

  The reformed water evaporator 26 evaporates the water (reformed water) sent from the flocculated water tank 20 that stores the flocculated water from the hot water heat exchanger 18 through the water supply line LW to produce steam for reforming. Is to be generated. In the present embodiment, the reformed water from the water supply line LW is introduced into the reformed water evaporator 26 together with the raw fuel gas from the fuel supply line LF1. The steam (reforming steam) generated by the reforming water evaporator 26 is introduced into the reformer 22 together with the raw fuel gas from the fuel supply line LF2. The reformer 22 may have a known configuration, and various reforming catalysts are provided therein. The fuel is introduced into the reformer 22 together with the steam generated by the reforming water evaporator 26, for example, in a state of being heated to about 300 ° C., where the temperature is increased to about 700 ° C. and the steam is reformed and reformed. It becomes quality fuel. A configuration may be adopted in which only the reforming water is introduced into the reforming water evaporator 26, the reforming steam generated here is mixed with the raw fuel gas flowing through the fuel supply line LF1, and then introduced into the reformer 22. Good.

  Air from the air supply line LA1 is introduced into the air preheater 24 by the blower 32, preheated to a desired temperature (for example, about 650 to 700 ° C.), and then introduced from the air supply line LA2 to the air electrode 14b. The

  The exhaust gas from the fuel cell stack 14 is sent to the hot water heat exchanger 18 from the exhaust gas line LG. The hot water heat exchanger 18 produces hot water by heating the water supplied from the water storage tank 36 with the exhaust gas from the exhaust gas line LG, and the produced hot water is returned to the water storage tank 36. In the water storage tank 36, makeup water is supplied and warm water is taken out. Further, the exhaust gas that has passed through the hot water heat exchanger 18 is condensed and removed by the condensed water tank 20 and exhausted. The condensed water is supplied to the reforming water evaporator 26 as reforming water. The condensed water tank 20 is provided with a level meter, and makeup water is supplied when the water is below a certain level. Thereby, unnecessary gas and excess water are exhausted and drained.

  Next, a specific configuration example of the fuel cell module 10 constituting the power generation device 12 as described above will be described.

  FIG. 2 is a perspective view showing a configuration example of the fuel cell module 10 according to an embodiment of the present invention, and a part thereof is shown in cross section. In the following, for each component of the fuel cell module 10, the front side in FIG. 2 is referred to as the front side (front side), the back side is referred to as the rear side (rear side), and the left-right direction is referred to as the width direction (left-right width direction). The direction will be referred to as the vertical direction.

  As shown in FIG. 2, in this embodiment, a fuel cell module 10 having a set of four units in which four fuel cell stacks 14 are provided in one heat insulating casing 16 is used. In the fuel cell module 10, two fuel cell stacks 14 are placed on the upper shelf 40a and the lower shelf 40b of the shelf device 40 installed in the heat insulating casing 16, and arranged in two rows and two columns in front view. It has become. Hereinafter, such a set of four fuel cell stacks 14 may be collectively described as the fuel cell stack 14.

  In the fuel cell module 10, a flat box-shaped reformer 22 is installed along the vertical direction so as to face the front of the fuel cell stack 14 placed on the shelf device 40, and flattened above the fuel cell stack 14. A box-shaped reforming water evaporator 26 is installed, and an air preheater 24 is installed so as to surround the side surface of the fuel cell stack 14.

  The reformer 22 has a flat plate type structure having a flat plate type reforming reaction portion (catalyst layer) 22a provided with various reforming catalysts therein. The reformer 22 is disposed along the vertical direction in the heat insulating casing 16 and is in parallel with the fuel cell stack 14.

  The upper end surface of the reformer 22 is provided with an inlet port (inlet) 23 to which a fuel supply line LF2 through which the raw fuel gas exiting the reformed water evaporator 26 flows is connected. Is provided with an outlet port (outlet) 25 to which a fuel supply line LF3 for supplying reformed fuel to the fuel cell stack 14 is connected. That is, the inlet port 23 is provided in the upper part of the reforming reaction part 22a, and the outlet port 25 is provided in the lower part of the reforming reaction part 22a. Therefore, the raw fuel gas and the reforming steam introduced from the inlet port 23 to the reformer 22 are reformed and generated in a flow (down flow) from the upper part to the lower part in the reformer 22. The reformed fuel (hydrogen) is supplied from the outlet port 25 to the fuel electrode 14 a of the fuel cell stack 14.

  In the case of this embodiment, each fuel supply line LF3 from the outlet port 25 serving as the fuel gas outlet of the reformer 22 to each fuel cell stack 14 is adjusted so that the inner diameter and the pipe length of each pipe are the same. doing. Thereby, the supply gas can be equally distributed from the reformer 22 to each fuel cell stack 14, and the performance of each fuel cell stack 14 can be balanced. Even when the number of the fuel cell stacks 14 is further increased, a stable system efficiency can be obtained by the same countermeasure. Moreover, if a heat insulating material is installed between the reformer 22 and each pipe, the heat reception of the pipe can be suppressed, and fluctuations in the temperature of the fuel gas supplied to each fuel cell stack 14 can be suppressed.

  The air introduced into the air preheater 24 via the air supply line LA1 flows through the preheater and is heated to a desired temperature, and then introduced from the air supply line LA2 to the air electrode 14b of the fuel cell stack 14. Is done.

  The reforming water evaporator 26 is a flat rectangular parallelepiped box 60 that evaporates the reforming water in the internal space to generate reforming steam, and a bracket when the box 60 is installed in the fuel cell module 10. A mounting member 62 is provided. The reformed water evaporator 26 includes an inlet pipe 64 that serves as an inlet for the reformed water from the water supply line LW and the raw fuel gas from the fuel supply line LF1, and an outlet for the raw fuel gas and the generated reforming steam. And an outlet pipe 66 is provided.

  The exhaust gas discharged from the fuel cell stack 14 is sent from the exhaust gas line LG to the external hot water heat exchanger 18 as shown in FIG.

  In the fuel cell module 10 according to the present embodiment, the reformer 22 and the air preheater 24 that require higher temperatures are disposed on the side surfaces of the fuel cell stack 14 in the heat insulating casing 16, and at lower temperatures than these. A good reforming water evaporator 26 is placed above the fuel cell stack 14.

  The reformer 22 is in the shape of a flat box as described above, is opposed to the fuel exhaust gas discharge surface 42 of each fuel cell stack 14, and is disposed along the vertical direction so as to cover the front surface thereof. For this reason, the radiant heat of the combustion flame generated in the heat insulating casing 16, the convective heat transfer of the high-temperature combustion exhaust gas, and the radiant heat from the fuel cell stack 14 operating at a high temperature can be efficiently applied to the reformer 22. Furthermore, an inlet port 23 that serves as an inlet for raw fuel gas to the reformer 22 is provided at the upper portion of the reforming reaction section 22a. For this reason, the heat concentrated in the upper part in the heat insulation housing | casing 16 can be given to the inlet_port | entrance side of the reforming reaction part 22a which requires the largest heat | fever with the reformer 22. FIG. Therefore, the heat utilization efficiency in the heat insulating casing 16 can be increased, the reforming rate in the reformer 22 can be improved, and the power generation efficiency in the entire fuel cell module 10 can be improved.

  A reforming water evaporator 26 that operates at a temperature lower than that of the reformer 22 and the air preheater 24 is disposed above the fuel cell stack 14, thereby efficiently generating heat generated in the heat insulating casing 16. Can be received. Thereby, the produced steam for reforming can be sufficiently heated to a desired superheated state. In addition, since the reforming water evaporator 26 is installed above the fuel cell stack 14 and the inlet port 23 of the reformer 22 is installed at the upper part, the raw fuel gas and reforming steam flow between them. Smoothens the piping structure and the like.

  As described above, in the fuel cell module 10 according to the present embodiment, the reformer 22, the air preheater 24, and the reformed water evaporator 26 are installed so as to surround the fuel cell stack 14. The radiant heat and the like of the fuel cell stack 14 generated inside can be efficiently recovered by each device. Therefore, the reforming efficiency in the reformer 22, the preheating efficiency in the air preheater 24, and further the heating efficiency with the reforming steam can be improved, and heat radiation from the heat insulating casing 16 to the outside can be reduced. Therefore, the heat self-supporting in the module can be maintained. Thereby, the fall of the fuel utilization rate in the fuel cell stack 14 is prevented, and the power generation efficiency of the entire apparatus can be maintained.

  By the way, the reformer 22 has a shorter depth dimension than its height dimension and width dimension, so that the reformer 22 falls in the back direction (the direction of the fuel cell stack 14), or moves due to vibration from the connected device. There is a concern of deviation (see FIG. 2). Therefore, in the present embodiment, the reformer 22 is supported by the support base 67 having a function of suppressing the overturning and displacement in the back direction (see FIG. 2).

  FIG. 3 is a configuration diagram illustrating an example of a support base 67 for supporting the reformer 22 in the heat insulating housing 16, FIG. 3A is a side view, and FIG. 3B is a rear view. FIG. 3C is a bottom view. As shown in FIGS. 2 and 3, the support base 67 includes a leg portion 68 and a holding portion 69 that holds the reformer 22 at the upper portion of the leg portion 68, for example, both side portions in the width direction of the reformer 22. Are attached to the left and right pair. The leg portion 68 has a leg plate 68a protruding toward the front side (opposite side of the fuel cell stack 14), and the floor of the heat insulating casing 16 is used by using a mounting hole 68b provided on the front end side of the leg plate 68a. It is fixed on the surface (see FIG. 2). The holding portion 69 is engaged with a hook 69b having a key claw structure formed at the upper end of the reformer 22 having the lower end surface placed on the placement surface 69a which is the upper surface of the leg portion 68. is there.

  The support base 67 has the leg plate 68a that protrudes toward the front side and lands on the floor surface as described above, so that the rotational moment against the weight of the reformer 22 is improved, so Is suppressed. That is, the center of gravity of the reformer 22 moves in the front direction, and the overturn and the position shift in the back direction are suppressed. On the other hand, since the fuel cell stack 14 is disposed in the rear direction, it is difficult to extend the leg portion 68 like the leg plate 68a. Therefore, by providing a hook 69b that holds the upper edge of the reformer 22 at the upper part of the holding unit 69, the reformer 22 can be reliably prevented from falling or tilting without protruding a leg plate or the like in the back direction. ing. Although not shown in the figure, the heat radiation of the reformer 22 can be suppressed by arranging a heat insulating material so as to be sandwiched between the reformer 22 and the support base 67.

  Although the flat plate type reformer 22 has been exemplified above, the fuel cell module 10 may of course be equipped with a reformer having another structure. For example, as shown in FIG. 4, a tubular type in which a plurality (three in FIG. 4) of reforming reaction parts (catalyst layers) 70a of a tubular type (cylindrical type) in which various reforming catalysts are provided are arranged in parallel. A reformer 70 having a structure may be used. In the reformer 70, the upper part of each reforming reaction part 70a is connected by an inlet connecting pipe 72, the lower part is connected by an outlet connecting pipe 74, and the inlet connecting pipe 72 is provided with the inlet port 23, and the outlet connecting pipe 72 An outlet port 25 is provided at 74. The reformer 70 having such a configuration is also disposed in the fuel cell module 10 in place of the reformer 22 shown in FIG. 2 in such a posture that the inlet connecting pipe 72 is at the top and the outlet connecting pipe 74 is at the bottom. Thus, a high reforming rate can be obtained.

  FIG. 5 shows the case where the raw fuel gas is flowed in the down flow using the reformer 22 of the present embodiment, and the raw fuel gas is flowed from the lower part to the upper part with the same equipment configuration as the reformer 22. It is the graph which compared the reforming performance with respect to the temperature of the reformer in the case (up flow). In FIG. 5, the square shape indicates the reforming rate (DF) in the down flow of the present embodiment, and the rhombus shape indicates the reforming rate (UF) in the up flow as a comparative example.

  As is apparent from FIGS. 2 and 4, the inlet port 23 of the reforming reaction portion 22 a of the reformer 22 having a large endothermic reaction amount is disposed in the heat insulating housing 16 at the top of the fuel cell module 10 where heat is easily generated. In the configuration of the present embodiment, it has been found that heat over the top can be efficiently recovered, and as a result, the reforming performance is improved. On the other hand, in the configuration of the comparative example in which the inlet port 23 of the reforming reaction section 22a of the reformer 22 is arranged in the lower part of the fuel cell module 10 in the heat insulating casing 16, the heat over the upper part can be efficiently recovered. As a result, it was found that the reforming performance deteriorates.

  It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be freely changed without departing from the gist of the present invention.

  For example, in the above embodiment, the configuration in which the fuel cell stacks 14 are used as one set of four or one set is illustrated, but it goes without saying that the number of the fuel cell stacks 14 can be changed as appropriate. Further, the fuel cell stack 14 may have a configuration in which one or a plurality of cylindrical power generation cells are provided instead of the rectangular laminated shape. However, considering the reforming rate in the reformer 22 (70), the reformer 22 (70) is attached to the discharge surface 42 of each fuel cell stack 14 even when the number of the fuel cell stacks 14 is changed. It is desirable to arrange them facing each other.

DESCRIPTION OF SYMBOLS 10 Fuel cell module 12 Electric power generating apparatus 14 Fuel cell stack 14a Fuel electrode 14b Air electrode 16 Heat insulation housing | casing 22,70 Reformer 22a, 70a Reformation reaction part 23 Inlet port 24 Air preheater 25 Outlet port 26 Reformed water evaporator 42, 44 Discharge surface 67 Support base LA1, LA2 Air supply line LF1-LF3 Fuel supply line LW Water supply line

Claims (7)

A fuel cell stack and a reformer that generates reformed fuel by a steam reforming reaction using reforming steam and raw fuel gas, and supplies the generated reformed fuel to the fuel cell stack are housed in a heat insulating casing. A fuel cell module,
The reformer is disposed along the vertical direction in the heat insulating casing, and has an inlet for the raw fuel gas at an upper portion thereof. The fuel cell module according to claim 1, wherein
The fuel cell module, wherein the reformer is disposed to face a side surface of the fuel cell stack. The fuel cell module according to claim 1 or 2,
A reforming water evaporator for generating the reforming steam;
The fuel cell module, wherein the reformed water evaporator is installed above the fuel cell stack in the heat insulating casing. The fuel cell module according to claim 1 or 2,
The fuel cell module, wherein the reformer has a flat plate structure having a flat plate reforming reaction section or a tubular structure having a tubular reforming reaction section. The fuel cell module according to claim 2, wherein
A plurality of the fuel cell stacks are arranged, and the reformer is opposed to a side surface of each fuel cell stack. The fuel cell module according to claim 1 or 2,
A plurality of the fuel cell stacks are arranged, and an inner diameter and a pipe length of each pipe from a fuel gas outlet of the reformer to each fuel cell stack are set to be the same. The fuel cell module according to claim 1 or 2,
A fuel cell module comprising a support base for supporting the reformer, wherein a key claw structure for engaging an upper edge portion of the reformer is provided on an upper portion of the support base.

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