JP5203598B2 - Solid electrolyte fuel cell module and air supply method for solid electrolyte fuel cell - Google Patents

Description

  The present invention relates to a solid electrolyte fuel cell module capable of reducing the size of the module and an air supply method for the solid electrolyte fuel cell.

  In the solid oxide fuel cell, in order to realize a self-supporting operation using heat generated during power generation, in the conventional structure, a heat insulating material is installed around the power generation chamber to suppress the heat radiation from the power generation chamber.

  Conventionally, a high-temperature solid electrolyte fuel cell has an operating temperature as high as 800 ° C. to 1000 ° C., and it is necessary to maintain the power generation chamber including the solid electrolyte fuel cell stack at a high temperature. In addition, regenerative heat exchange is performed with exhaust air using an air heat exchanger to preheat supply air, and radiation conversion is performed using heat radiated from a high-temperature fuel cell stack using a radiation converter. The body is heating the air.

  FIG. 7 shows a conventional solid electrolyte fuel cell module (hereinafter also referred to as “module”) 20. Reference numeral 21 in FIG. 7 indicates a heat insulating portion made of a heat insulating material that keeps the entire module warm. The region surrounded by the heat insulating portion 21 is separated into a power generation chamber 24, a fuel discharge chamber 25, and a fuel supply chamber 26 in this order from the lower side by the lower tube plate 22 and the upper tube plate 23. Here, the lower tube sheet 22 supports a high-temperature solid electrolyte fuel cell stack 27 described later, and at the same time, prevents the fuel exhaust gas 40 and the air 45 in the power generation chamber 24 from being mixed and burned. The upper tube plate 23 serves as a partition wall between a fuel supply chamber 26 and a fuel discharge chamber 25 while supporting a fuel supply tube, which will be described later. In the power generation chamber 24, a cylindrical high-temperature solid electrolyte fuel cell stack 27 is disposed, in which a plurality of solid electrolyte fuel cells each having a fuel electrode (not shown) on the inside and an air electrode on the outside are connected in series. . A radiation converter 28 using a porous thermoelectric material is disposed below the power generation chamber 24.

  A fuel supply pipe 29 having one end (upper end) communicating with the fuel supply chamber 26 is disposed in the solid electrolyte fuel cell stack 27. An air exhaust pipe 30 is provided in the power generation chamber 24, and an air heat exchanger 31 is communicated with the lower portion of the air exhaust pipe 30. The fuel gas is supplied to the fuel supply chamber 26. The fuel gas is supplied from the fuel supply chamber 26 to the solid electrolyte fuel cell stack 27 through the fuel supply pipe 29 and used for power generation, and then collected in the fuel discharge chamber 25 and exhausted. The air is preheated by the regenerative heat exchange with the exhausted air by the air heat exchanger 31. The radiation converter 28 receives the heat radiated from the high-temperature solid electrolyte fuel cell stack 27 and further heats the preheated air. By using the heat generated in the power generation chamber 24 to heat the air in the radiation converter 28, the temperature rise of the air in the power generation chamber 24 is suppressed, and the temperature difference between the upper and lower portions in the power generation chamber 24 is reduced. Is made smaller.

  The air 45 is supplied from the radiation converter 28 to the power generation chamber 24, generates power in the power generation chamber 24, is heated to 900 to 1000 ° C., is collected in the air discharge pipe 30, and is supplied to the air heat exchanger 31. It is sent and exhausted as exhaust air 46. It is necessary to keep the inside of the power generation chamber 24 at a high temperature of 900 to 1000 ° C., and the entire module is kept warm by the heat insulating portion 21 (Patent Document 1).

JP 09-289030 A

  By the way, although the said heat insulation part 21 increases the heat insulation effect, the heat insulation material volume which occupies for a module is large, From the viewpoint of promoting the miniaturization of a module, it is desirable to achieve thinning of a heat insulation material.

However, the mere thinning of the heat insulating material has a problem that it causes a problem of heat resistance of a current collecting component due to an increase in the ambient temperature in the module and a decrease in system efficiency due to an increase in the amount of heat radiation.
On the other hand, if a high-performance heat insulating material that suppresses heat dissipation is used, it is possible to reduce the thickness of the heat insulating portion 21, but the use of the high-performance heat insulating material increases the manufacturing cost. is there.

  In view of the above problems, an object of the present invention is to provide a solid electrolyte fuel cell module and a method for supplying air to the solid electrolyte fuel cell that can reduce the size of the module.

A first invention of the present invention for solving the above-mentioned problems is to connect a plurality of cylindrical solid electrolyte fuel cells provided in a power generation chamber and the power generation chamber and having a fuel electrode inside and an air electrode outside. and Luz tack such and a fuel supply chamber for supplying fuel to the stack, a fuel discharge chamber for discharging the reacted fuel side exhaust gas by the solid electrolyte fuel cell to the outside, as well as thermal insulation around the power generating chamber An air supply pipe for supplying air into the power generation chamber is disposed in at least one surface, and includes a heat insulating furnace wall portion for heating air supplied by heat radiation from the power generation chamber, and the cylinder When using heat radiation from the stack of the mold, heating the supply air from the outside flowing through the air supply pipe, the temperature distribution of the cells of the stack , when the air supply pipe is not arranged in the heat insulation furnace wall compared to hula In the solid electrolyte fuel cell module which is characterized by comprising collected by reduction.

  A second invention is the solid electrolyte fuel cell module according to the first invention, wherein the air supply pipe disposed in the central portion of the power generation chamber has a heat release portion.

  According to a third invention, there is provided the solid electrolyte fuel cell module according to the second invention, wherein the heat release portion is a fin.

A fourth invention uses the heat radiation from the generator chamber to arrange the absence tack such connecting a solid electrolyte fuel cell of the cylindrical multiple series, the air supply pipe to the power generation chamber the heat insulating furnace wall portion insulating the surroundings When the air supplied to the power generation chamber is heated, the temperature distribution of the cells of the stack is flattened as compared with the case where the air supply pipe is not provided in the heat insulation furnace wall. It is in the air supply method of a solid electrolyte fuel cell.

According to a fifth aspect of the present invention, in the fourth aspect of the invention, the amount of air to be supplied is reduced by supplying air while reducing the amount of air to be supplied compared to the case where the air supply pipe is not disposed in the heat insulating furnace wall , thereby improving the power generation efficiency of the system. The present invention relates to an air supply method for a solid electrolyte fuel cell.

  According to the present invention, since the air supply pipe for supplying air into the power generation chamber is disposed inside the heat insulation furnace wall, the air can be heated by heat radiation from the power generation chamber, and the amount of heat released to the outside is reduced. Thus, the heat insulation furnace wall can be thinned.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

An embodiment according to the present invention will be described with reference to the drawings.
FIG. 1 is a conceptual diagram illustrating a solid electrolyte fuel cell module according to an embodiment. FIG. 2 is a schematic perspective view with the inside omitted.
As shown in FIGS. 1 and 2, a solid electrolyte fuel cell module 10A according to this embodiment includes a power generation chamber 24 and a solid electrolyte provided in the power generation chamber 24, with a fuel electrode on the inside and an air electrode on the outside. A cylindrical stack 27 in which a plurality of fuel cells are connected in series, a fuel supply chamber 26 for supplying fuel 41 to the stack 27, and a fuel for exhausting the fuel side exhaust gas 41 reacted in the solid electrolyte fuel cell to the outside The discharge chamber 25, one end of which communicates with the fuel supply chamber 26, the other end of which extends to the tip of the stack 27, heat insulation around the power generation chamber 24, and the inside of the power generation chamber 24 The air supply pipe 11 for supplying the air 45 is provided on at least one surface, and includes the heat insulation furnace wall portion 12 for heating the air 45 supplied by heat radiation from the power generation chamber 24. For the connection of the cylindrical stack 27, for example, a plurality of parallel connections may be used in addition to the plurality of series connections.

  Here, in this embodiment, the structure for supporting the cylindrical stack 27 is a one-end support structure as shown in FIG. 1, but the present invention is not limited to this, for example, as shown in FIG. Other structures such as the solid electrolyte fuel cell module 10A that supports the cylindrical stack 27 at both ends may be used.

In the present invention, as shown in FIG. 3A, an air supply pipe 11 that can ventilate supply air (about 400 ° C.) 45 a is provided in the heat insulating structure on the side wall of the power generation chamber 24 to supply the heat radiation amount from the power generation chamber 24. Heat is actively received by the air 45 and heat exchange air (about 500 ° C.) can be introduced into the power generation chamber 24, and the heat insulation furnace wall 12 is cooled by the heat exchange, so that necessary heat insulation material can be obtained. Thinning can be achieved.
The air supply pipe 11 may be disposed on at least one side surface of the heat insulating furnace wall 12 that covers the periphery of the power generation chamber 24. However, the air supply pipe 11 is extended over the entire periphery of the facing furnace wall or the furnace wall. It may be arranged. In addition, when a plurality of modules are connected, an air supply pipe may be similarly disposed on the furnace wall portion covering the periphery thereof.

  As a specific structure, as shown in FIG. 2, the heat insulating material on the side wall of the power generation chamber 24 is processed and an air supply line is disposed, or a small diameter pipe is embedded in the heat insulating material. The heat exchange by heat dissipation is attempted by the structure etc. The air supply pipe is not limited to series connection.

  According to the present invention, as described above, since the heat radiation in the power generation chamber is actively released to the outside, the heat insulating material can be thinned, and as a result, the module can be reduced in size.

  In the conventional structure, as shown in FIG. 3-2, the heating of the supply air (about 400 ° C.) 45a is performed by the heat exchange of the air heat exchanger 31 using the exhaust air 46 from the module. Then, since it heats using the heat radiation from a furnace wall part, the heat exchanger 31 used conventionally is unnecessary.

  In addition, since the temperature distribution of the cells of the cylindrical stack 27 in the conventional structure is roughly a bow-shaped temperature distribution in the vertical axis direction as shown in FIG. 4-2, to increase the cell output It is effective to squeeze the supply air 45 and raise the temperature of the entire cell, but only a part of the cell (particularly the central part) touches the heat-resistant temperature (about 930 ° C.), so the supply air cannot be squeezed As a result, the output could not be increased.

  On the other hand, in this embodiment, the heat radiation from the wall surface of the power generation chamber can be ensured larger than in the conventional case (FIG. 3-1), so that the temperature distribution of the cells of the cylindrical stack 27 can be flattened (FIG. 4-1). Dotted line). As a result, the supply air flow rate can be reduced from the conventional flow rate, the temperature of the entire cell can be raised, and the system efficiency can be improved.

  That is, in the conventional heat insulation structure, the temperature distribution of the cell is about 100 ° C. or more in the axial direction, and if the supply air amount is reduced in order to increase the whole cell in anticipation of an increase in cell output, Since the cell temperature (in the center) of the cell was in contact with the heat-resistant temperature, it was forced to operate at a low air utilization rate.

  On the other hand, when the heat insulating structure of the present invention is applied, such a situation is solved, operation at a higher air utilization rate is possible, and system efficiency can be improved. Further, since the temperature distribution of the cell is expected to be flattened at a higher temperature (the chain line in FIG. 4A), the cell output is further improved.

  On the other hand, when the supplied air 45 has the same supply amount as in the conventional case, it becomes a dotted line, and when the air is squeezed, it becomes arcuate over the axial direction. Further, by improving the balance between the upper and lower sides, it becomes like a one-dot chain line, and the system efficiency can be improved.

  Therefore, according to the present invention, the air utilization rate can be improved by 10 to 15%, and the output can be significantly improved by 15 to 20% or more.

Further, as shown in FIG. 6, for the air supply pipe 11 disposed in the central portion 13 of the power generation chamber 24, a heat release part such as a fin is provided so that heat transfer can be promoted. Heat dissipation from the inside of the power generation chamber may be promoted to further improve heat exchange efficiency.
Or you may make it make it the structure which raises the arrangement | positioning density of piping of an air line.

  As described above, according to the solid electrolyte fuel cell module according to the present invention, a thin heat insulating furnace wall portion that exchanges heat with air that supplies heat radiated from the inside is provided without using an expensive high-performance heat insulating material. Thus, the module can be reduced in size.

It is a conceptual diagram which shows the solid electrolyte fuel cell module which concerns on a present Example. It is the isometric view schematic which abbreviate | omitted the inside. It is a furnace wall heat insulation structure conceptual diagram concerning a present Example. It is a furnace wall heat insulation structure conceptual diagram concerning a prior art. It is a figure which shows the relationship between the temperature distribution of a cell axial direction and the cell height direction temperature distribution which concern on a present Example. It is a figure which shows the relationship between the temperature distribution of a cell axis direction and the cell height direction temperature distribution which concern on a prior art. It is a conceptual diagram which shows the solid electrolyte fuel cell module which concerns on a present Example. It is a conceptual diagram which shows the other solid electrolyte fuel cell module which concerns on a present Example. It is a conceptual diagram which shows the body electrolyte fuel cell module which concerns on a prior art.

DESCRIPTION OF SYMBOLS 10, 20 Solid electrolyte fuel cell module 11 Air supply piping 12 Heat insulation furnace wall part 21 Heat insulating material 22 Lower tube plate 23 Upper tube plate 24 Power generation chamber 25 Fuel discharge chamber 26 Fuel supply chamber 27 Cylindrical stack 28 Radiation conversion body 29 Fuel Supply pipe 30 Air exhaust pipe 31 Air heat exchanger 40 Fuel 41 Exhaust fuel 45 Air 46 Exhaust air

Claims (5)

A power generation room,
Provided in the power generating chamber, and the absence tack such by connecting a plurality of solid electrolyte fuel cell of the cylindrical disposing the air electrode to the fuel electrode to the outside to the inside,
A fuel supply chamber for supplying fuel to the stack;
A fuel discharge chamber for discharging the fuel side exhaust gas reacted in the solid electrolyte fuel cell to the outside;
A heat insulating furnace wall that heats the air supplied by heat radiation from the power generation chamber, wherein the periphery of the power generation chamber is insulated and an air supply pipe for supplying air to the power generation chamber is disposed in at least one surface. And comprising
Using heat radiation from the cylindrical stack, the external supply air flowing in the air supply pipe is heated, and the temperature distribution of the cells of the stack is not arranged in the heat insulation furnace wall. A solid electrolyte fuel cell module characterized by being flattened compared to the case . In claim 1,
A solid electrolyte fuel cell module, wherein an air supply pipe disposed in a central portion of the power generation chamber has a heat release portion. In claim 2,
The solid electrolyte fuel cell module, wherein the heat release part is a fin. Using the heat radiation from the generator chamber to arrange the absence tack such connecting a solid electrolyte fuel cell of the cylindrical multiple series, an air supply pipe disposed in the power generating chamber heat insulating furnace wall portion to insulate the periphery, power generating chamber When heating the air supplied to the stack, the temperature distribution of the cells of the stack is flattened as compared with the case where the air supply pipe is not arranged in the heat insulating furnace wall. Supply method. In claim 4,
Compared with the case where the air supply pipe is not disposed in the heat insulation furnace wall portion, the air supply is performed while the air is supplied and heat exchange is performed, and the power generation efficiency of the system is improved. Air supply method.

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