JP2012252801A - Solid oxide fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid oxide fuel cell which facilitates cooling in a power generation chamber.SOLUTION: A solid oxide fuel cell supplies a fuel gas 121 that is a first gas to the interior of a cylindrical cell tube 102 while supplying air 122 that is a second gas to a fuel cell provided on outer surface of the cell tube 102 and causes the first gas and the second gas to electrochemically react to generate power. A core cylinder for heat exchange 14 of the solid oxide fuel cell is inserted into an entire body of the cell tube 102.

Description

  The present invention relates to a solid oxide fuel cell having a core as a heat exchange aid.

  A fuel cell is a power generation device using an electrochemical reaction, and has excellent power generation efficiency and environmental characteristics. For this reason, research and development for practical use is progressing as an urban energy supply system for the 21st century.

  As an example of a conventional fuel cell, a one-through type fuel cell has been proposed. This one-through type fuel cell is, for example, a fuel cell in which fuel gas is supplied from one end (for example, the upper end) of the cell tube and discharged from the other end (for example, the lower end) of the cell tube. Further, the oxidant gas is supplied to the outer peripheral surface of the cell tube.

  Further, in order to generate power, a chemical reaction in a high temperature environment in which the inside of the fuel cell module is about 800 ° C. to 1000 ° C. is used. It is necessary to preheat. This is because if the supplied gas is not preheated, the temperature of the fuel battery cell is lowered, resulting in a risk that power generation efficiency is lowered and power generation itself is unstable.

  This preheating is performed using high-temperature exhaust gas from the viewpoint of efficiency. That is, heat exchange is performed between the high-temperature exhaust fuel gas discharged from the discharge chamber and the oxidant gas (air) supplied to the fuel cell to preheat the oxidant gas. Further, heat exchange is performed between the high-temperature exhaust oxidant gas and the fuel gas supplied to the fuel cell to preheat the fuel gas. For this reason, a core is installed in the exhaust gas discharge path as an auxiliary device for efficiently performing heat exchange (see, for example, Patent Documents 1 and 2).

JP 2002-63916 A JP 2004-127640 A

  By the way, the temperature inside the power generation chamber is kept below the control value temperature by adjusting the supply air amount. However, in the future, if the output density is increased and the size is reduced for cost reduction, the heat generation per unit volume is generated. Since the density increases, it is necessary to promote cooling of the power generation chamber.

  However, when the flow rate of air supplied to the fuel cell is increased, the power required for supplying air also increases, and the efficiency of the entire system decreases. For example, in the case of a combined system with a gas turbine, the flow rate of air supplied to the fuel cell is often limited due to the rated operation on the gas turbine side.

  In view of the above problems, an object of the present invention is to provide a solid oxide fuel cell that can promote cooling in a power generation chamber.

  The first invention of the present invention for solving the above-described problem is to supply the first gas into the inside of the cylindrical cell tube and to supply the second gas to the fuel cell provided on the outer surface of the cell tube. A solid oxide fuel cell that generates electricity by electrochemically reacting the first gas and the second gas in the fuel cell by supplying the solid oxide fuel cell for heat exchange. The solid oxide fuel cell is characterized in that the core is inserted throughout the interior of the cell tube.

  According to a second aspect, in the first aspect, the heat exchange core has a support member having the same diameter as the diameter of the cell tube, and is supported by being bonded to the upper end opening of the cell tube. The solid oxide fuel cell is characterized.

  A third invention is the one-through type fuel cell according to the first or second invention, wherein the first gas is supplied from one end of the cell tube and the first gas is discharged from the other end of the cell tube. The solid oxide fuel cell is characterized by the following.

  A fourth invention provides a solid oxide fuel cell according to any one of the first to third inventions, wherein the first gas is a fuel gas and the second gas is an oxidant gas. is there.

  A fifth invention provides a solid oxide fuel cell according to any one of the first to third inventions, wherein the first gas is an oxidant gas and the second gas is a fuel gas. is there.

  According to a sixth invention, in any one of the first to fifth inventions, a plurality of the cell tubes are disposed in the fuel cell module, and the fuel cell module includes a casing made of a heat insulating material, and a casing. The upper tube plate and the lower tube plate that support both ends of the cell tube, the upper and lower heat insulators disposed between the upper and lower tube plates, and the space between the upper and lower heat insulators are formed. A solid oxide fuel cell characterized by comprising a power generation chamber.

  According to the present invention, using the heat exchange core, by inserting the entire cell tube, not only the heat exchange part, but also heat exchange in the power generation chamber can be made favorable. Cooling in the power generation chamber can be promoted.

FIG. 1 is a schematic configuration diagram showing a solid oxide fuel cell module. FIG. 2 is a perspective view of a heat exchange core of the solid oxide fuel cell. FIG. 3 is another perspective view of the core for heat exchange of the solid oxide fuel cell. FIG. 4-1 is a schematic diagram of a support structure of a heat exchange core and a support member. FIG. 4B is a schematic diagram of a support structure of the heat exchange core and the support member.

  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.

  A solid oxide fuel cell having a core as a heat exchange aid according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a solid oxide fuel cell module.

  As shown in FIG. 1, a solid oxide fuel cell module (hereinafter also referred to as “fuel cell module”) 100 according to the present embodiment includes a casing 101 that is a heat insulating material and a plurality of cell tubes formed in a substantially cylindrical shape. 102, upper and lower tube plates (first partition members) 103a and 103b that support both ends of the cell tube 102, and upper and lower heat insulators 104a and 104b disposed between the upper and lower tube plates 103a and 103b. Has been.

  A power generation chamber 105 is formed in a space between the upper and lower heat insulators 104a and 104b. A fuel supply chamber 106 is formed between the casing 101 and the upper tube plate 103a. A fuel discharge chamber 107 is formed between the casing 101 and the lower tube plate 103b. An air supply chamber 108 is formed between the lower tube plate 103b and the lower heat insulator 104b. An air discharge chamber 109 is formed between the upper tube plate 103a and the upper heat insulator 104a.

  The upper tube plate 103a is a plate-like member disposed on one side (upper side) of the casing 101 in the longitudinal direction (vertical direction in FIG. 1), and the lower tube plate 103b is the other side (lower side) of the casing 101 in the longitudinal direction. ) Is a plate-shaped member. The cell tube 102 is a substantially cylindrical tube made of porous ceramics, and is provided with a plurality of fuel cells 110 that generate power at the center in the longitudinal direction (vertical direction in FIG. 1). In this embodiment, the fuel cell 110 is formed by laminating a fuel electrode, a solid electrolyte, and an air electrode in this order. The cell tube 102 is supported by the upper and lower tube plates 103a and 103b so that one open end opens to the fuel supply chamber 106 and the other open end opens to the fuel discharge chamber 107. Further, the cell tube 102 is arranged so that the fuel battery cell (power generation element) 110 is located only in the power generation chamber 105.

  The upper heat insulator 104a is a member that is disposed on one side (upper side) in the longitudinal direction of the casing 101 and is formed in a blanket shape or a board shape using a heat insulating material. The lower heat insulating material 104b is a member that is disposed on the other side (lower side) of the casing 101 in the longitudinal direction and formed in a blanket shape or a board shape using a heat insulating material. The heat insulators 104a and 104b are formed with holes 111a and 111b through which the cell tubes 102 are inserted, and the diameters of the holes 111a and 111b are larger than the diameter of the cell tubes 102.

  The inner peripheral surfaces of the holes 111a and 111b may be formed in a substantially cylindrical shape, or may be formed with a spiral or linear concave portion (groove) or convex portion (a ridge-like projection), There is no particular limitation. With such a configuration, the heat of the exhaust combustion gas 121a and the lower heat insulator 104b is easily transmitted to the air flowing into the power generation chamber 105 through the space between the cell tube 102 and the hole 111b. The temperature of can be easily maintained at a high temperature. Similarly, the fuel gas 121 introduced into the cell tube 102 can be heated to high temperature by transferring the heat of the exhaust air 122a discharged from the power generation chamber 105 through the space between the cell tube 102 and the hole 111a.

Further, a heat exchange core 14 is inserted into the cell tube 102 over the entire length of the cell tube 102 in the longitudinal direction (from the upper end to the end of the cell tube). For example, in the case of a cell tube having an inner diameter of 22 mm, a heat exchange core of 19 mm is used, but the present invention is not limited to this.
By supplying the fuel gas 121 between the outer wall of the core 14 for heat exchange and the inner wall of the cell tube 102, heat exchange with the air 122 which is an oxidant gas flowing on the outer periphery of the cell tube 102 is improved. Yes.
That is, the upper heat insulating body 104a region forms the upper heat exchanging portion 123a, and the lower heat insulating body 104b region forms the lower heat exchanging portion 123b. The upper heat exchange section 123a exchanges heat between the introduced fuel gas 121 and the discharged exhaust air 122a, and the lower heat exchange section 123b exchanges heat between the introduced air 122 and the exhaust fuel gas 121a. Made.

  Further, in this embodiment, since the heat exchange core 14 is also present in the center portion of the cell tube 102 in the longitudinal direction inside the cell tube 102, in the region corresponding to the power generation chamber 105 of the cell tube 102. Also, cooling in the power generation chamber can be promoted.

  In this way, the conventional cooling mechanism has inserted the core into the cell lead as a cooling part at both ends of the power generation chamber (two locations on the top and bottom), but for heat exchange throughout the cell tube. By inserting the core 14, cooling from the fuel side can be promoted also inside the power generation chamber 105.

  As a result, even if the heat generation density per unit volume increases due to high power density and compactness, not only can the inside of the power generation chamber be cooled, but also cost reduction by reducing the number of parts. be able to.

  For cooling the inside of the power generation chamber, for example, when applying a gas turbine combined system or the like, even if there is a restriction on the flow rate of air supplied to the fuel cell due to the rated operation on the gas turbine side, Cooling can be supported by inserting the child all over.

  Here, the material for the heat exchange core is preferably made of ceramics from the viewpoint of heat resistance at the high temperature part.

FIG. 2 is a perspective view of a heat exchange core of the solid oxide fuel cell. FIG. 3 is another perspective view of the core for heat exchange of the solid oxide fuel cell.
As shown in FIG. 2, the core 14 for heat exchange inserted into the cell tube (fuel cell) 102 of the present embodiment has a support member 11A having a flange 11a supported by the upper end opening of the cell tube 102 at the top. Have.
The flange 11 a is provided so as to extend from the support member in at least three directions, and is placed on the upper end opening of the cell tube 102. The fuel gas 121 flows into the inside through a gap not covered with the flange 11a.

Further, as shown in FIG. 3, a flange-type support member 11 </ b> B may be provided and supported by the upper end opening of the cell tube 102.
In the case of this support member 11B, it is set as the ceramic foam and it adhere | attached with the adhesive agent.
This ceramic foam is made of, for example, a mixture of cordierite and alumina, has a three-dimensional skeleton structure with continuous pores, has a high porosity, and facilitates the inflow of the fuel gas 121.

4A and 4B are schematic views of a support structure of the heat exchange core and the support member.
FIG. 4A is a support structure when the support member 11A having the flange 11a is used, and FIG. 4B is a support structure when the support member 11B is used.

Here, in Figure 4-1, the flange 11a and four directions, diameter and the diameter d ₁ which combined two collars 11a at both ends of the supporting member 11A is set to be equal to the diameter d ₂ of the cell tube, both ends The flange 11a is joined with an adhesive 15.
As a result, when all the flanges 11a provided on the support member 11A have the same length in advance, the heat exchanging core 14 can be easily centered so as to be at the center position of the cell tube.

Further, as shown in Figure 4-2, when the support member 11B, by the diameter d ₂ of the diameter d ₃ and the cell tube 102 of the support member 11B is formed on the same, the upper end surface of the cell tube 102 When the support member 11B is placed on the center, centering can be easily performed.
As a result, it is not necessary to provide an extra centering member for centering on the outer peripheral surface of the heat exchanging core 14, and the heat exchanging core 14 does not require extra machining. In addition, centering can be reliably performed with a simple structure.

  In this embodiment, the heat exchanging core 14 is supported by providing the support member 11A or the support member 11B on the upper end surface of the cell tube 102. For example, the lower end surface of the core is discharged from the fuel. The chamber 107 may be mounted on the wall opposite to the lower tube plate 103b, that is, on the wall of the casing 101. In this case, the heat exchanging core 14 needs to be disposed at the center of the cell tube by a centering member which is separately received.

  Here, an outline of the operation of the fuel cell module 100 configured as described above will be described.

Air 122 flows into the air supply chamber 108 of the fuel cell module 100. The air 122 is supplied into the power generation chamber 105 through a gap between the hole 111 b of the lower heat insulating material 104 b and the cell tube 102.
On the other hand, the fuel gas 121 flows into the fuel supply chamber 106. The fuel gas 121 is supplied into the power generation chamber 105 through the inside of the base tube of the cell tube 102. The air 122 and the fuel gas 121 are used for power generation in the fuel battery cell 110. Thereafter, the discharged air 122a flows into the air discharge chamber 109, and the discharged fuel gas 121a flows into the fuel discharge chamber 107 and is discharged from the discharge ports 101a and 101b to the outside of the fuel cell module 100, respectively.

  At this time, the air 122 and the fuel gas 121 are flowing in opposite directions on the inner surface or outer surface of the cell tube 102. As a result, the fuel gas and air that have been used for power generation and have reached a high temperature are each subjected to heat exchange with the air and fuel gas before being used for power generation. That is, the fuel gas 121 and the air 122 are heat-exchanged in the heat exchanging regions of the upper heat exchanging portion 123a and the lower heat exchanging portion 123b, which are axial end portions of the cell tube 102 and where the fuel cell 110 is not formed. The

  As described above, in the fuel cell module 100, the exhausted fuel gas 121a and the exhausted air 122a, which have been used for the reaction and become high temperature, are cooled by heat exchange and then supplied to the fuel exhaust chamber 107 and the air exhaust chamber 109. This can prevent the upper tube plate 103a and the lower tube plate 103b having metal members from being exposed to a high temperature atmosphere. As a result, in the fuel cell module 100, the operating temperature of the fuel cell 110 can be increased, for example, from 800 ° C. to 950 ° C.

  In this embodiment, the fuel gas is exemplified as the first gas, and the oxidant gas (air) is exemplified as the second gas. However, the present invention is not limited to this, and the cell structure is reversed, and the oxidant gas ( Air) and fuel gas as the second gas may be supplied.

  As described above, according to the present invention, the heat exchange core 14 is used to be inserted over the entire cell tube 102, so that not only the heat exchange parts 123 a and 123 b but also the inside of the power generation chamber 105. Heat exchange can be improved, cooling in the power generation chamber is promoted, and the temperature of about 950 ° C. can be maintained as much as possible, and the flow rate of air to be supplied can be suppressed, thereby improving system efficiency.

11A, 11B Support member 14 Core for heat exchange 102 Cell tube 121 Fuel gas 122 Air

Claims (6)

The first gas and the first gas are supplied to the fuel cell by supplying the first gas into the cylindrical cell tube and supplying the second gas to the fuel cell provided on the outer surface of the cell tube. A solid oxide fuel cell that generates electricity by electrochemically reacting with two gases,
A solid oxide fuel cell, characterized in that a heat exchange core of the solid oxide fuel cell is inserted throughout the inside of the cell tube. In claim 1,
The solid oxide fuel cell, wherein the heat exchange core has a support member having the same diameter as the cell tube, and is bonded and supported to an upper end opening of the cell tube. In claim 1 or 2,
A solid oxide fuel cell, wherein the first gas is supplied from one end of the cell tube and the first gas is discharged from the other end of the cell tube. In any one of Claims 1 thru | or 3,
The solid oxide fuel cell, wherein the first gas is a fuel gas and the second gas is an oxidant gas. In any one of Claims 1 thru | or 3,
The solid oxide fuel cell, wherein the first gas is an oxidant gas and the second gas is a fuel gas. In any one of Claims 1 thru | or 5,
A plurality of the cell tubes are disposed in the fuel cell module,
The fuel cell module is
A casing made of heat insulating material;
Provided in the casing,
An upper tube plate and a lower tube plate supporting both ends of the cell tube;
An upper insulator and a lower insulator disposed between upper and lower tube sheets;
A solid oxide fuel cell comprising a power generation chamber formed in a space sandwiched between upper and lower heat insulators.

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