JP2009170170A - Solid oxide fuel cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid oxide fuel cell module of direct internal reforming type which can generate power stably with high energy efficiency, and is made compact in size. <P>SOLUTION: The fuel cell module houses a solid oxide fuel battery cell to generate power, by causing fuel reforming reaction in a cylindrical heat insulation container of which one end part in axial direction is closed by an upper heat insulation wall. The heat insulation container has a cell portion space to house one or a plurality of fuel battery cells and a preheating space to house a heat exchange unit for carrying out heat exchanging, between the inlet gas to be introduced into the fuel battery cells and the exhaust gas from the fuel battery cells, which is provided with an inner heat insulating barrier rib which is substantially in parallel with the axial direction for partitioning the inside of the heat insulating container. Furthermore, the fuel cell module is provided with a lower heat insulation wall to close the cell portion space at the other end part in axial direction, and a communication port provided in the inner heat insulating barrier rib, communicating the cell portion space and the preheating space in the vicinity of the upper heat insulation wall. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell module in which a fuel cell is accommodated in a heat insulating container, and particularly to a solid oxide fuel cell module in which a solid oxide fuel cell is accommodated in a heat insulating container.

  Fuel cells are classified into solid polymer type, phosphoric acid type, molten carbonate type, solid oxide type, etc., depending on the type of electrolyte sandwiched between a pair of electrodes. In each of these electrolytes, the temperature at which the optimum ionic conductivity for obtaining the fuel cell can be greatly varied. Therefore, each fuel cell is operated while being held at a predetermined temperature for each type of electrolyte.

  Here, a solid oxide fuel cell (Solid Oxide Fuel Cell: hereinafter referred to as SOFC) is operated at a higher temperature than other electrolyte fuel cells. For example, SOFCs using solid oxide electrolytes such as yttria partially stabilized zirconia, scandia stabilized zirconia, samaria doped ceria, gadolinium doped ceria are known. In these SOFCs, a pair of electrodes made of a porous material is provided on both sides of an electrolyte, and fuel gas (hydrogen and carbon monoxide) and an oxidant gas such as air are supplied to the outside of each electrode. Is operated at 700 to 1000 ° C. Specifically, oxygen ions in the oxidant gas that has received electrons at the cathode move to the anode side through the solid oxide electrolyte and react with fuel gas (hydrogen and carbon monoxide) on the surface of the anode. Electrons are emitted to the anode while producing water and carbon dioxide. Carbon dioxide and unburned fuel gas are discharged from the SOFC as exhaust gas.

  By the way, there is known an SOFC system in which exhaust heat generated by exhaust gas discharged from an SOFC operated at a high temperature as described above is used as a heat source for various devices to improve the energy efficiency of the entire system.

  For example, an SOFC system that uses exhaust heat of exhaust gas from SOFC is known as a heat source of a reformer that generates fuel gas supplied to SOFC from hydrocarbon fuel such as kerosene or natural gas. In the reformer, a hydrocarbon-based fuel is brought into contact with a platinum group-based reforming catalyst together with steam at a high temperature to cause a steam reforming reaction to generate fuel gas (hydrogen and carbon monoxide). Here, the exhaust gas from the SOFC is introduced into the reformer, and the hydrocarbon fuel and water vapor (or water) are heated by the heat exchanger.

  For example, Patent Document 1 discloses an SOFC system that includes an SOFC and a reformer and that is thermally independent. The reformer has a reforming section and an oxidation heating section, and uses a combination of exhaust heat generated from SOFC and heat generated in the oxidation heating section as a heat source for the steam reforming reaction in the reforming section. Yes. As a result, the exhaust heat generated from the SOFC can be used without waste for the steam reforming reaction of the reformer, and when the amount of heat required for the steam reforming reaction is insufficient, the oxidation exothermic reaction proceeds in the reformer and the amount of heat is increased. Is supplemented.

  Furthermore, an SOFC system that uses radiant heat from the SOFC as a heat source for various devices is also known.

  For example, Patent Document 2 discloses an SOFC system in which radiant heat from an SOFC is directly guided to an endothermic reaction vessel and used as a heat source. The exhaust heat of the power generation reaction in the SOFC is transferred to the endothermic reaction vessel adjacent to the SOFC by radiant heat from the outer surface, and heat is supplied even if the unreacted air inside the heat insulation vessel is led to the endothermic reaction vessel as a heat medium. It is.

Further, Patent Document 3 discloses an SOFC system that uses radiant heat from the SOFC as a heat source of the reformer. A reformer for reforming kerosene to low carbon compounds such as hydrogen, carbon dioxide, and carbon monoxide is disposed at a position where radiant heat transfer is available in the SOFC system. The SOFC system states that energy efficiency can be improved because it does not have an independent heat source for the reformer.
JP 2007-227237 A JP 2005-174551 A Japanese Patent Laid-Open No. 2007-179885

  As described above, the SOFC operated at a high temperature is superior in energy efficiency as compared with other electrolyte fuel cells.

  Accordingly, an object of the present invention is to provide a compact solid oxide fuel cell module that can stably generate power with higher energy efficiency.

  The present invention is a fuel cell module in which a solid oxide fuel cell is accommodated in a cylindrical heat insulating container in which one end in an axial direction is closed with an upper heat insulating wall. A pre-heater that houses a cell space that houses one or more of the fuel cells, and a heat exchanger unit that exchanges heat between the introduced gas introduced into the fuel cells and the exhaust gas from the fuel cells. An internal heat insulating partition that is substantially parallel to the axial direction partitioning the interior of the heat insulating container into a partial space, a lower heat insulating wall that closes the cell partial space at the other end of the axial direction, and an upper insulating wall And a communication port provided in the internal heat insulating partition communicating with the cell part space and the preheating part space in the vicinity.

  According to the present invention, radiant heat from a high-temperature SOFC can be confined in the cell space, and the SOFC can be operated stably. Further, the exhaust gas from the SOFC, which is a heat transfer medium, can be led from the cell space to the preheating space via a communication port at a shorter distance, and energy loss can be further reduced. In addition, in the preheating part space separated by the cell part space and the internal heat insulating partition, the introduced gas is preheated by the exhaust gas and then introduced into the SOFC, so the temperature fluctuation of the SOFC can be reduced and the SOFC can be operated stably. It can be done. Further, since the cell part space and the preheating part space are provided by partitioning the inside of one heat insulating container with an internal heat insulating partition, the SOFC module can be made compact. That is, it is possible to provide a compact solid oxide fuel cell module having high energy efficiency.

  In one aspect of the present invention, a fuel cell module includes a cylindrical heat insulating container having a cylindrical or polygonal cross section that houses a solid oxide fuel cell (hereinafter referred to as SOFC) inside. . Such a heat insulating container includes an internal heat insulating partition that partitions the internal space into a cell space and a preheating space. The inner heat insulating partition is substantially parallel to the axial direction of the heat insulating container and partitions the heat insulating container into two spaces. One end of the heat insulating container in the axial direction is provided with an upper heat insulating wall for closing the upper part of the cylindrical heat insulating container, and the other end is provided with a lower heat insulating wall for closing at least the lower part of the cell part space. . That is, the cell space is defined by the inner heat insulating partition and the lower heat insulating wall in the cylindrical heat insulating container.

  In the upper part of the inner heat insulating partition wall, that is, in the vicinity of the upper heat insulating wall, a communication port for communicating the cell part space and the preheating part space is provided. One or more SOFCs are accommodated in the cell space. A heat exchanger unit for performing heat exchange between the introduced gas introduced into the SOFC and the exhaust gas discharged from the SOFC is accommodated in the preheating space inside the heat insulating container. In other words, the heat generated by the power generation reaction of the SOFC is led from the cell space to the preheating space through the communication port using the exhaust gas as a heat medium, and heats the introduced gas introduced into the SOFC by the heat exchanger unit. is there. In addition, a meandering passage that repeatedly flows in a direction perpendicular to the axial direction of the heat insulating unit, that is, the axial direction of the heat exchanger unit is provided inside the heat exchanger unit, and a contact path with the introduced gas flowing in the axial direction. Heat exchange efficiency can be increased by increasing the length.

  According to the above aspect, since the passage from the cell part space to the preheating part space is only the communication port provided in the internal heat insulating partition wall, the radiant heat from the high temperature SOFC can be effectively confined in the cell part space. Thus, fluctuations in the surface temperature of the SOFC can be prevented and the SOFC can be operated stably. In addition, if a radiant heat reflective film is provided on the surfaces of the heat insulating container inner surface, the inner heat insulating partition, the upper heat insulating wall, and the lower heat insulating wall facing the cell space, the radiant heat can be efficiently confined in the cell space. As a result, fluctuations in the surface temperature of the SOFC can be further reduced, so that the temperature of the exhaust gas from the SOFC can be maintained at a high temperature.

  Further, the exhaust gas from the SOFC, which is a heat transfer medium, can be guided from the cell part space stably maintained at a high temperature to the preheating part space through a communication port at a shorter distance. Energy loss can be further reduced.

  In addition, in the preheating part space separated by the cell part space and the internal heat insulating partition, the introduced gas is preheated by the exhaust gas and then introduced into the SOFC, so that the temperature fluctuation of the SOFC, that is, the temperature drop can be reduced. Thus, the SOFC can be operated stably.

  In addition, since the cell space and the preheating space have a simple structure provided such that the inside of one heat insulating container is partitioned by an internal heat insulating partition, the SOFC module that achieves high energy efficiency as described above is used for home use. It can be made more compact to the extent that it can be installed.

  As described above, since the heat energy leaking to the outside of the heat insulating container can be suppressed to a very low level, high energy efficiency can be achieved by the heat generated by the power generation reaction, and a compact solid oxide fuel cell module can be provided. It is.

  Note that the SOFC may be a direct internal reforming fuel cell that generates power while reforming at least a part of the introduced gas into hydrogen and / or carbon monoxide. Although the steam reforming reaction for reforming the introduced gas is an endothermic reaction, as described above, it is possible to achieve high thermal efficiency that can reduce the temperature fluctuation of the SOFC, so that it consists of a direct internal reforming fuel cell. Even an SOFC can be operated stably.

  In addition, at least one of the introduction gases to be introduced into the SOFC may be, for example, a hydrocarbon-based fuel, for example, a gas such as methane, but is a liquid that is introduced into the SOFC module and gasified. There may be. That is, the liquid raw fuel can be vaporized in the module. In such a case, it is not necessary to install a vaporizer or the like for vaporizing liquid fuel outside the module, so that a compact SOFC system can be provided. Furthermore, since the liquid can be vaporized inside the SOFC module having high energy efficiency as described above, the thermal efficiency of the SOFC system as a whole can be increased compared to the case where a normal vaporizer is separately provided. is there.

  Furthermore, a heater for heating the introduced gas introduced into the SOFC may be provided in the vicinity of the communication port. When starting the SOFC module or when the temperature of the introduced gas is lowered, especially when introducing liquid as raw fuel into the SOFC module, as described above, the temperature of the introduced gas to the SOFC can be increased. The SOFC can be operated stably.

  In addition, it is preferable that the upper heat insulating wall and / or the lower heat insulating wall be detachable from the heat insulating container because maintenance inside the heat insulating container becomes easy.

  Next, a fuel cell module according to one embodiment of the present invention will be described in detail with reference to FIGS.

  As shown in FIG. 1, the fuel cell module 1 includes one or a plurality of direct internal reforming SOFCs 40, which will be described later, in a can body 10 'in a substantially cylindrical heat insulating container (2, 4, 5). The fuel cell assembly 10, the oxidant gas pipe 16 ′ and the mixed gas pipe 17 ′ are introduced into the fuel battery cell assembly 10 through the exhaust gas pipe 19 and the exhaust gas pipe 19 is discharged from the fuel battery cell assembly 10. A heat exchanger unit 12 for exchanging heat with the exhaust gas is accommodated. As will be described later, as can be seen from FIG. 1, the shape of the space inside the heat insulating container (2, 4, 5) partitioned by the internal heat insulating partition 3 is "" It has become.

  Specifically, the heat insulating container body 2 constituting a part of the heat insulating container (2, 4, 5) is an inner peripheral surface of a core vacuum heat insulating can 2a in which a double cylinder made of a metal material such as stainless steel is evacuated. And it is the triple heat insulation container which provided the heat insulating material 2b along the outer peripheral surface. Furthermore, the outer wall material 2c is given along the outer peripheral surface of the heat insulating material 2b.

  A plate-like internal heat insulating partition wall 3 having a main surface substantially parallel to the axis of the cylindrical heat insulating container main body 2 is provided in the internal space of the cylindrical heat insulating container main body 2. By the internal heat insulating partition wall 3, the internal space of the heat insulating container body 2 is partitioned into two spaces, a cell space 6 and a preheating space 7. The internal heat insulating partition 3 is a triple heat insulating plate-like member in which a core vacuum heat insulating can 3a whose inside is evacuated is sandwiched between heat insulating materials 3b. The internal heat insulating partition 3 is provided with a communication port 8 that is a small window that allows communication between the cell space 6 and the preheating space 7. For example, the communication port 8 may be a gap provided between an upper end portion of the internal heat insulating partition 3 and an upper heat insulating wall 4 described later. In order to efficiently confine radiant heat from a fuel cell assembly 10 (described later) accommodated in the cell space 6 to the cell space 6, the cross-sectional area of the communication port 8 is preferably as small as possible. Furthermore, for example, a portion other than the gas passage that passes through the communication port 8 may be sealed with a heat insulating material.

  The upper heat insulating wall 4 is a disc-shaped triple heat insulating member in which a core vacuum heat insulating can 4a whose inside is evacuated is sandwiched between heat insulating materials 4b. In addition, the outer wall material 4c is given to the top surface along this. The upper heat insulating wall 4 is combined with the heat insulating container body 2 so as to be openable and closable so as to close an upper end which is one end in the axial direction of the heat insulating container main body 2. That is, the upper heat insulating wall 4 is detachably engaged with the heat insulating container body 2 by the clasp 9 and closes the upper portions of the cell portion space 6 and the preheating portion space 7 so as to be freely opened and closed. That is, the operator can operate the clasp 9 to remove the upper heat insulating wall 4 from the heat insulating container body 2, and the fuel cell assembly 10 accommodated in the cell space 6 and the preheating space 7 and The maintenance of the heat exchanger unit 12 and the like can be easily performed with good operability.

  Similarly to the upper heat insulating wall 4, the lower heat insulating wall 5 is a triple heat insulating member in which a core vacuum heat insulating can 5a whose inside is evacuated is sandwiched between heat insulating materials 5b. In addition, it is preferable to give the outer wall material 5c to the bottom face of the lower heat insulating wall 5. The lower heat insulating wall 5 is combined with the heat insulating container body 2 so as to be openable and closable so as to close the cell space 6 at the lower end in the axial direction of the heat insulating container body 2. That is, the lower heat insulating wall 5 is detachably engaged with the heat insulating container body 2 by the clasp 9 to close the lower part of the cell part space 6 so as to be opened and closed. That is, similarly to the upper heat insulating wall 4, the operator can operate the clasp 9 to remove the lower heat insulating wall 5 from the heat insulating container body 2, and the fuel cell accommodated in the cell space 6. Maintenance of the assembly 10 can be easily performed with good operability.

  Here, in the contact portion T1 between the heat insulating container body 2 and the upper heat insulating wall 4 and the lower heat insulating wall 5, the core vacuum heat insulating can 2a of the heat insulating container main body 2 is above and below the heat insulating material 2b sandwiching the inner periphery and outer periphery thereof. It protrudes in the direction. The protrusion has a structure that is fitted into a recess formed in the heat insulating material 4 b of the upper heat insulating wall 4 and the heat insulating material 5 b of the lower heat insulating wall 5. Preferably, the core vacuum insulation can 2a is in contact with the core vacuum insulation cans 4a and 5a, respectively.

  The core vacuum heat insulating can 3a protrudes downward with respect to the heat insulating material 3b at the portion T2 of the inner heat insulating partition 3 that contacts the lower heat insulating wall 5, and is formed on the heat insulating material 5b of the lower heat insulating wall 5. It is fitted in the recess. Preferably, the core vacuum heat insulating can 3a is in contact with the core vacuum heat insulating can 5a.

  Further, although not shown in the drawing, a similar fitting structure is also formed in the portions where the internal heat insulating partition wall 3 and the heat insulating container body 2 abut (the front side and the back side in FIG. 1).

  By arranging the core vacuum heat insulating cans (2a, 3a, 4a, 5a) and the heat insulating materials (2b, 3b, 4b, 5b) as described above, the heat insulating properties of the heat insulating containers (2, 4, 5) can be further improved. It can be done. That is, since the cell space 6 is covered with the core vacuum insulation cans (2a, 3a, 4a, 5a) without any gaps, the heat dissipation to the outside of the heat insulation container can be greatly reduced. is there. A part of the heat insulating container body 2, the inner heat insulating partition wall 3, the upper heat insulating wall 4 and the lower heat insulating wall 5 surrounding the cell space 6 are mirror-finished or a radiant heat reflecting film (2d, 3d, 4d, 5d) is provided. It is preferably pasted or coated. The radiant heat reflection film (2d, 3d, 4d, 5d) efficiently confines radiant heat from a fuel cell assembly 10 (described later) accommodated in the cell part space 6 to the cell part space 6.

  By confining the radiant heat from the fuel cell assembly 10 in the cell space 6, fluctuations in the gas temperature existing in the cell space 6 are reduced, that is, the heat fluctuations of the fuel cell assembly 10 are maintained while maintaining the high temperature. Can be reduced.

  Furthermore, the heat insulating material (2b, 3b, 4b, 5b) can be prevented from being overheated by the radiant heat reflecting film (2d, 3d, 4d, 5d), and the life of the heat insulating container can be improved.

  Moreover, it is preferable that the core vacuum heat insulating can (2a, 3a, 4a, 5a) is filled with a filler made of a material having low thermal conductivity such as ceramic particles. Even if the temperature of the core vacuum insulation can (2a, 3a, 4a, 5a) rises and the proof stress is reduced, the can can be prevented from being crushed. Moreover, even if the can wall and the filler are in contact with each other, heat loss hardly occurs because the filler has low thermal conductivity.

  The upper heat insulating wall 4 and / or the lower heat insulating wall 5 may be provided integrally with the heat insulating container body 2 as necessary. Moreover, you may use another well-known heat insulating material for the heat insulation container main body 2, the internal heat insulation partition 3, the upper heat insulation wall 4, and / or the lower heat insulation wall 5 as needed. Furthermore, as long as the shape of the heat insulation container main body 2 is cylindrical, it may be a rectangular tube, for example, a polygonal tube such as a square tube or a hexagonal tube.

  Here, the SOFC 40 included in the fuel cell assembly 10 is preferably a solid oxide fuel cell, and the type thereof is not particularly limited, but is a direct internal reforming solid oxide fuel cell. However, the effect of the present invention is effective. That is, according to the present invention, as will be described later, it is possible to suppress a reduction in power generation efficiency due to heat absorption associated with reforming on the SOFC 40, and to achieve high energy efficiency and a compact solid oxide fuel cell. Modules can be provided.

A direct internal reforming SOFC 40 used in this embodiment will be described with reference to FIGS. The direct internal reforming SOFC 40 immediately performs a power generation reaction with the generated fuel gas composed of CO and H ₂ while causing a steam reforming reaction on the fuel electrode 41. Such an SOFC 40 has a sandwich structure in which a porous fuel electrode (anode) 41 and an air electrode (cathode) 43 are provided on both sides of an electrolyte 42 made of a known solid oxide. An oxidant gas such as air is guided to the outside of the air electrode 43 by an oxidant gas pipe 16 ′ (see particularly FIG. 1). On the other hand, an introduction gas composed of a hydrocarbon fuel gas and water vapor is guided to the outside of the fuel electrode 41 by a mixed gas pipe 17 ′ (see particularly FIG. 1). Oxygen in the oxidant gas that has received electrons at the air electrode 43 becomes oxygen ions and moves to the fuel electrode 41 through the electrolyte 42. In the fuel electrode 41, a fuel made of carbon monoxide or hydrogen is brought into contact with a known platinum group catalyst (not shown) supported in the fuel electrode 41 made of a porous material by a steam reforming reaction. It produces gas. Carbon monoxide and hydrogen generated by the steam reforming reaction react with oxygen ions supplied through the electrolyte 42 to generate water and carbon dioxide, and discharge electrons to the fuel electrode 41. On the other hand, water, carbon dioxide and unburned fuel gas generated by the reaction are discharged from the SOFC 40 through the exhaust gas pipe 19 (see particularly FIG. 1) as a heated exhaust gas.

  Further, referring to FIGS. 4 to 6 in conjunction with FIG. 1, the preheating space 7 has an exhaust gas exhausted from the SOFC 40 of the fuel cell assembly 10 by the exhaust gas pipe 19 and an oxidant gas pipe 16 ′ and A heat exchanger unit 12 that performs heat exchange with the introduced gas supplied to the SOFC 40 of the fuel cell assembly 10 by the mixed gas pipe 17 ′ is accommodated.

  The heat exchanger unit 12 has a housing 33 made of metal that is accommodated in the preheating part space 7 with almost no gap. A lower oxidant gas chamber 21 for storing an oxidant gas, a heating pool 22 for storing water, and a hydrocarbon-based raw fuel made of a liquid such as kerosene are stored at the lower part of the housing 33. A raw fuel chamber 23 is provided.

  The lower oxidant gas chamber 21 guides the oxidant gas from the outside of the housing 33 through the oxidant gas inlet 13 and moves upward (the X direction shown in FIG. 4 is a vertical direction). The agent gas heat exchange pipe 25 is extended to communicate with an upper oxidant gas chamber 35 provided at the upper part of the housing 33.

  The heating pool 22 guides water from the outside of the housing 33 through the water inlet 14 and extends a plurality of steam heat exchange pipes 26 upward so as to be parallel to the X direction. It communicates with a water vapor outlet 29 provided at the top.

  The raw fuel chamber 23 guides the raw fuel from the outside of the housing 33 through the raw fuel introduction port 15 and extends a plurality of raw fuel gas heat exchange pipes 27 upward so as to be parallel to the X direction. The raw fuel gas chamber 37 provided in the upper part of the housing 33 communicates with the raw fuel gas chamber 37. A gas fuel such as methane can be used as the raw fuel. In such a case, it is preferable to provide a gas backflow prevention valve between the raw fuel chamber 23 and the raw fuel inlet 15.

  Inside the housing 33 of the heat exchanger unit 12, baffle plates 32 are arranged at regular intervals in the extending X direction of the oxidant gas heat exchange pipe 25, the steam heat exchange pipe 26 and the raw fuel gas heat exchange pipe 27. Each pipe (25, 26, 27) extends through the baffle plate 32. Here, the baffle plate 32 forms a gap 34 between the housing 33 and the end portion of the baffle plate 32 so as to form a meandering passage that repeatedly flows in a direction perpendicular to the X direction. That is, the gaps 34 at the left and right end portions of the baffle plates 32 arranged in the X direction are alternately provided at the left and right end portions, and the flow path through which the exhaust gas flows is defined as the meandering path E. The gap 34 may be a through hole provided in the baffle plate 32. As described above, the exhaust gas does not flow along the oxidant gas heat exchange pipe 25, the steam heat exchange pipe 26, and the raw fuel gas heat exchange pipe 27, but the contact time between the two is increased by using the meandering path E. Therefore, the heat exchange efficiency between the exhaust gas and the liquid or gas in each pipe (25, 26, 27) can be improved. Further, since the exhaust gas flows so as to surround the pipes (25, 26, 27) perpendicularly to the extending direction, turbulent flow is formed behind the pipes (25, 26, 27) to exchange heat. It increases the rate.

  At the upper end of the housing 33 of the heat exchanger unit 12, an exhaust gas introduction port 24 that guides exhaust gas to the heat exchanger unit 12 is provided and connected to the exhaust gas pipe 19. Moreover, the lower end part of the housing | casing 33 is opening, and becomes the exhaust-gas discharge port 20 for discharging | emitting the exhaust gas which passed the above-mentioned meander path E. As shown in FIG. The exhaust gas temperature of the exhaust gas discharge port 20 is preferably set to a predetermined temperature, and the heat insulating container (2, 3, 4, 5) and the heat exchanger unit are set so as to be approximately the set temperature required for stable operation. The arrangement of the baffles 32 that defines the axial length, such as 12, and the length of the meander path E is determined.

  An oxidant gas discharge port 28 is provided in the upper oxidant gas chamber 35 of the heat exchanger unit 12, and the oxidant gas is guided to the heater 11 described later via the oxidant gas pipe 16. On the other hand, the water vapor chamber 36 is provided with a water vapor outlet 29 for introducing water or water vapor to the heater 11 via the water vapor pipe 17. Further, the raw fuel gas chamber 37 is provided with a raw fuel discharge port 30, and the liquid raw fuel or the raw fuel gas is guided to the heater 11 through the raw fuel pipe 18.

  In the case where the liquid is vaporized in the steam heat exchange pipe 26 and the raw fuel gas heat exchange pipe 27, it is preferable to fill the inside thereof with heat conductive beads or the like (not shown). Heat exchange between the liquid flowing inside each pipe (26, 27) and each pipe (26, 27) is promoted by the heat conductive beads. Such techniques are well known and will not be described in detail.

  Referring to FIGS. 1 and 6, the heater 11 is installed in the vicinity of the communication port 8 that connects the cell space 6 and the preheating space 7. That is, the heater 11 may be installed in the preheating part space 7 as illustrated, or may be installed in the cell part space 6 that is a high temperature part. Moreover, you may install so that at least one part of the communicating port 8 may be obstruct | occluded across the preheating part space 7 and the cell part space 6. FIG. The heater 11 is between the oxidant gas pipes 16 and 16 'and can heat the oxidant gas as needed. Further, the water vapor pipe 17 and the raw fuel pipe 18 are coupled inside or outside the heater 11 and connected to the mixed gas pipe 17 ′. That is, the heater 11 can heat steam (or water) and raw fuel gas (or liquid raw fuel) as necessary, mix them, and discharge them as a mixed gas. A pre-reformer (not shown) for adjusting the generation of fuel gas may be provided at such a position, or a pre-reformer (not shown) may be disposed in the mixed gas pipe 17 ′. . Since the steam reforming reaction by direct internal reforming is an endothermic reaction as described above, the heat balance of the fuel cell module 1 can be controlled by adjusting the amount of fuel gas generated on the SOFC 40.

  Specifically, as shown in FIG. 7, the heater 11 is introduced from the oxidizing gas introduced from the oxidizing gas pipe 16, the steam (or water) introduced from the steam pipe 17, and the raw fuel pipe 18. Heating means 39a, 39b, and 39c for individually heating each raw fuel gas (or liquid raw fuel). The heating means may be various known heating means such as an electric heater, but is preferably a burner that can be combusted using the raw fuel introduced into the fuel cell module 1. For example, the outputs of the burners 39a, 39b, 39c can be adjusted by the opening degree of a main valve 38e 'provided in a pipe for sending fuel to the burners 39a, 39b, 39c. Further, each burner 39a, 39b, 39c is provided with valves 38a ', 38b', 38c ', and the output of each burner can be further individually adjusted by the opening degree.

  Here, one method for controlling the heater 11 will be described. A thermal control sensor 38e for detecting temperature is provided at a predetermined position inside the fuel cell assembly 10. The opening degrees of the valves 38a ', 38b', 38c 'are fixed at predetermined opening degrees, respectively. On the other hand, if the supply amount of the raw fuel to the burners 39a, 39b, 39c is controlled while adjusting the opening of the valve 38e 'in response to the detection signal from the thermal control sensor 38e, the output can be controlled.

  As another control method of the heater 11, as shown in FIG. 8, the temperature of each gas introduced into the fuel cell assembly 10 is controlled by thermal control sensors 38a, 38b, and 38c provided at the outlet of the heater 11. You may carry out by detecting. The outputs of the burners 39a, 39b, and 39c are individually output while adjusting the opening degrees of the valves 38a ', 38b', and 38c 'in response to the detection signals from the thermal control sensors 38a, 38b, and 38c. Can be controlled.

  Further, referring to FIGS. 6 to 8, the exhaust gas discharged from the heater 11 is led from the heater exhaust gas pipe 44 to the heat exchanger unit 12 and used as a heat supply source together with the exhaust gas discharged from the SOFC 40. May be. Specifically, the flow rate of the oxidant gas including air supplied to the burners 39a, 39b, and 39c can be controlled by the flow control valve 38d '. If the oxidant gas is supplied in excess of the amount used for the combustion of the burners 39a, 39b, 39c, the excess oxidant gas is discharged from the heater exhaust gas pipe 44 as exhaust gas together with the gas generated by the combustion. 12 can be sent. The heater exhaust gas pipe 44 merges with the exhaust gas pipe 19 from the fuel cell assembly 10 or independently of the heater exhaust gas inlet (not shown) provided at the upper end of the heat exchanger unit 12. It is connected to.

  1 and FIG. 6, conduits for guiding the oxidant gas and the mixed gas to the fuel electrode 41 and the air electrode 43 of the SOFC 40 in the fuel cell assembly 10 are not shown.

  Next, the operation of the fuel cell module 1 will be described with reference to FIGS.

  In this embodiment, a raw fuel made of liquid or gas can be used. Here, a case where a liquid raw fuel is used will be described. The liquid raw fuel is preferably kerosene or synthetic kerosene, for example, a paraffinic synthetic liquid raw fuel having a sulfur content of 1 ppm or less, even if it is a direct internal reforming type SOFC 40, because high thermal efficiency can be obtained. However, the raw fuel is not limited to this.

  In particular, as shown in FIGS. 1, 4, 6, 7, and 8, when the fuel cell module 1 is started, the oxidant gas is supplied from the oxidant gas inlet 13 to the heat exchanger unit 12. It is guided to the heater 11 through the oxidant gas exhaust port 28 and the oxidant gas pipe 16 through the oxidant gas heat exchange pipe 25 in the heat exchanger unit 12. In the heater 11, the oxidant gas is heated by the burner 39a and led to the air electrode 43 (see FIG. 3) of the SOFC 40 in the fuel cell assembly 10 through the oxidant gas pipe 16 '.

  On the other hand, water passes through the water vapor heat exchange pipe 26 of the heat exchanger unit 12 from the water inlet 14 and is led to the heater 11 through the water vapor outlet 29 and the water vapor pipe 17. Further, the liquid raw fuel passes through the raw fuel gas heat exchange pipe 27 of the heat exchanger unit 12 from the raw fuel introduction port 15 and is led from the raw fuel discharge port 30 to the heater 11 through the raw fuel pipe 18. . In the heater 11, both the water and the liquid raw fuel are vaporized by the burners 39b and 39c, mixed together, and the fuel electrode 41 of the SOFC 40 in the fuel cell assembly 10 through the mixed gas pipe 17 ′ (see FIG. 3). It leads to.

As described with reference to FIGS. 2 and 3, the fuel electrode 41 generates a power generation reaction while generating a fuel gas composed of CO and H ₂ by a steam reforming reaction. Here, since the amount of heat generated by the power generation reaction, which is an exothermic reaction, is much larger than the amount of heat absorbed by the steam reforming reaction, the unreacted mixed gas, water vapor, etc. From the space 6, it passes through the exhaust gas pipe 19 and is conveyed to the preheating part space 7 communicating with the cell part space 6 through the communication port 8.

  This exhaust gas is introduced into the exhaust gas inlet 24 at the upper part of the heat exchanger unit 12, and is oxidized in the oxidant gas heat exchange pipe 25, the steam heat exchange pipe 26 and the raw fuel gas heat exchange pipe 27. Heat is exchanged with the agent gas, water, and liquid raw fuel to heat them. Here, since the exhaust gas from the fuel cell assembly 10 that is a heat transfer medium can be guided from the cell space 6 to the preheating space 7 through the communication port 8 at a shorter distance, the energy loss of the exhaust gas is reduced. The temperature of the oxidant gas, water, and liquid raw fuel in each pipe (25, 26, 27) can be rapidly increased. As described above, the exhaust gas from the heater 11 may be guided to the exhaust gas inlet 24.

  Further, when the surface temperature of the SOFC 40 in the fuel cell assembly 10 rises due to the power generation reaction, the cell part space 6 is closed except for the communication port 8, so the internal temperature of the cell part space 6 rapidly rises and the exhaust gas temperature Also rises. In the heat exchanger unit 12 having the meandering path E, the heat of the exhaust gas is efficiently transmitted to the oxidant gas, water, and liquid raw fuel in each pipe (25, 26, 27). The water and liquid raw fuel in the water vapor heat exchange pipe 26 and the raw fuel gas heat exchange pipe 27 are quickly vaporized to become water vapor and raw fuel gas. At this time, the output of the burner 39a, 39b, 39c of the heater 11 is changed to a valve in response to a signal from the above-described thermal control sensor 38e (see FIG. 7) or the thermal control sensors 38a, 38b, 38c (see FIG. 8). 38e ′ (see FIG. 7) or valves 38a ′, 38b ′, and 38c ′ (see FIG. 8) are throttled to suppress each.

  Further, when the surface temperature of the SOFC 40 in the fuel cell assembly 10 rises, the radiant heat emitted from the surface of the fuel cell assembly 10 increases. Here, since the radiant heat is effectively confined in the cell part space 6 other than the communication port 8, the temperature inside the cell part space 6 rises and stabilizes, so the temperature of the fuel cell assembly 10 also stabilizes. is there. Further, the trapped radiant heat is reflected in the cell space 6 and applied again to the fuel cell assembly 10 to stabilize the temperature of the fuel cell assembly 10. That is, the SOFC 40 can be operated stably.

  The exhaust gas whose temperature has risen can further increase the temperature of the oxidant gas, water vapor, and raw fuel gas in each pipe (25, 26, 27) in the heat exchanger unit 12, and is no longer caused by the heater 11. There is no need to heat these gases. That is, as described above, the outputs of the burners 39a, 39b, and 39c of the heater 11 corresponding to the signals from the thermal control sensor 38e (see FIG. 7) or the thermal control sensors 38a, 38b, and 38c (see FIG. 8). Further, it is suppressed or stopped.

  The opening / closing control of the valve 38e (see FIG. 7) or the valves 38a, 38b, 38c (see FIG. 8) may be step control in which the opening degree is changed stepwise as described above. It is good also as ON-OFF control used as either closed.

  In the case where the heat balance of the fuel cell module 1 is lost, such as when the temperature of the exhaust gas decreases again, the heater 11 is operated in response to the signal from the above-described heat control sensor 38 to reduce the amount of heat. Since it can be replenished, the fuel cell module 1 can be operated stably.

  As described above, in this embodiment, since the heat energy leaking to the outside of the heat insulating container (2, 4, 5) can be suppressed to a very low level, the fuel cell module 1 is made highly energy efficient by the heat generated by the power generation reaction. give. At the same time, it is possible to provide a compact solid oxide fuel cell module that can be accommodated in a range of a practical size for home use, for example, a diameter of about 10 cm to about 1 m.

  As mentioned above, although the typical Example by this invention and the modification based on this were described, this invention is not necessarily limited to these, Those skilled in the art do not deviate from the attached claim. Various alternative embodiments and modifications may be found.

It is sectional drawing of the principal part of the fuel cell module by this invention. It is a figure which shows a steam reforming reaction. It is an expanded sectional view of the principal part of the fuel cell module by this invention. It is a perspective view of the principal part of the fuel cell module by this invention. It is sectional drawing of the principal part of the fuel cell module by this invention. It is a block diagram of the principal part of the fuel cell module by this invention. It is a block diagram of the principal part of the fuel cell module by this invention. It is a block diagram of the principal part in the other Example of the fuel cell module by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell module 2 Heat insulation container main body 3 Internal heat insulation partition 4 Upper heat insulation wall 5 Lower heat insulation wall 6 Cell part space 7 Preheating part space 8 Communication port 10 Fuel cell assembly 11 Heater 12 Heat exchanger unit 32 Baffle board 34 Gap 39a 39b, 39c Burner 40 SOFC

Claims (9)

A fuel cell module in which a solid oxide fuel cell is housed in a cylindrical heat insulating container in which one of axial end portions is closed by an upper heat insulating wall,
A pre-heater that houses a cell space that houses one or more of the fuel cells, and a heat exchanger unit that exchanges heat between the introduced gas introduced into the fuel cells and the exhaust gas from the fuel cells. An internal heat insulating partition that is substantially parallel to the axial direction and partitions the interior of the heat insulating container into a partial space;
A lower heat insulating wall that closes the cell part space at the other end of the axial direction;
A solid oxide fuel cell module comprising: a communication port provided in the internal heat insulating partition that communicates the cell part space and the preheating part space in the vicinity of the upper heat insulating wall.   2. The solid oxide fuel cell module according to claim 1, wherein the fuel cell performs power generation while reforming at least a part of the introduced gas into hydrogen and / or carbon monoxide.   3. The solid oxide fuel cell module according to claim 1, wherein the heat exchanger unit guides a hydrocarbon fuel to the inside thereof and discharges it as at least a part of the introduced gas. 4.   4. The solid oxide fuel cell module according to claim 3, wherein the hydrocarbon fuel is a liquid fuel.   5. The solid oxide fuel cell module according to claim 1, wherein the heat exchanger unit has a meandering passage through which the exhaust gas repeatedly flows in a direction perpendicular to the axial direction. 6.   6. The solid oxide fuel cell module according to claim 1, wherein a heater for heating the introduced gas as needed is provided in the vicinity of the communication port. .   The solid oxide fuel cell module according to claim 1, wherein the heat insulating container has a cylindrical shape or a rectangular tube shape.   8. The solid oxide fuel cell module according to claim 1, wherein the upper heat insulating wall and / or the lower heat insulating wall are detachable. 9. The solid oxide fuel cell module according to claim 1, wherein a radiant heat reflecting film is provided on a surface facing the cell portion space. 10.