JP6506932B2 - Fuel cell reforming unit and fuel cell module - Google Patents

Description

  The present invention relates to a fuel cell reforming unit (a combustion unit, an evaporation unit, a reforming unit, and a heat exchange unit) that constitutes a fuel cell module together with a fuel cell stack in which a plurality of solid oxide fuel cells (SOFCs) are stacked. And a fuel cell module including such a fuel cell stack and a fuel cell reforming unit.

  A fuel cell module of a solid oxide fuel cell (SOFC) includes a fuel cell stack, which is an SOFC, and a fuel cell reforming unit (a combustion unit, an evaporation unit, a reforming unit, and a heat exchange unit).

  The combustion unit is a functional unit that burns the reformed gas not used in the fuel cell stack and transfers the heat generated by the combustion to the evaporation unit, the reforming unit, the heat exchange unit, and the fuel cell stack. .

The evaporation unit is a functional unit that takes in water from the outside, evaporates the water with the heat received from the combustion unit, generates water vapor, and sends the water vapor to the reforming unit.
The reforming unit warms the reforming catalyst with the heat received from the combustion unit, and reforms the mixed gas consisting of the raw fuel such as city gas and the steam sent from the evaporation unit through the warmed catalyst. It is a functional unit that generates a quality gas and sends the reformed gas to the fuel cell stack.

The heat exchange unit is a functional unit that raises the temperature of the oxidant gas by the heat received from the combustion unit and sends the heated oxidant gas to the fuel cell stack.
The fuel cell stack performs an electrochemical reaction between the reformed gas supplied from the reforming unit and the oxidant gas supplied from the heat exchange unit to generate power. At this time, the fuel cell stack needs to be kept at a high temperature, and if the temperature is lowered by the supplied gas, the power generation will be disturbed. Therefore, the fuel cell module is provided with a combustion unit, and the reformed gas and the oxidant gas entering the fuel cell stack are warmed, and the fuel cell stack is also warmed.

  A fuel cell module of this type is shown, for example, in Patent Document 1. In the fuel cell module disclosed in Patent Document 1, an evaporation unit and a reforming unit are disposed around the combustion unit, and a heat exchange unit is disposed outside the evaporation unit and the reforming unit. .

JP, 2014-78344, A

  However, in the fuel cell module disclosed in Patent Document 1, the heat exchange unit is located outside the evaporation unit and the reforming unit when viewed from the combustion unit. The heat exchange unit does not directly receive heat from the combustion unit, but indirectly receives heat via the exhaust gas discharged from the combustion unit. Specifically, the heat exchange unit receives heat from the exhaust gas whose heat has been removed by the evaporation unit and the reforming unit located between the heat exchange unit and the combustion unit.

  Therefore, the temperature of the heat received by the heat exchange unit from the combustion unit is considerably lower than that when heat is directly received from the combustion unit. As a result, since the fuel cell stack receives the supply of oxidant gas at a low temperature from the heat exchange unit, the power generation efficiency of the fuel cell stack is lowered by the amount of the low temperature.

  An object of the present invention is to improve the power generation efficiency of a fuel cell stack.

  One aspect of the present invention is a fuel cell reforming unit for forming a fuel cell module with a fuel cell stack in which a plurality of fuel cells that generate electric power by an electrochemical reaction between a reformed gas and an oxidant gas are stacked, An evaporation unit, a reforming unit, a heat exchange unit, and a combustion unit are provided. The evaporation unit generates water vapor. The reforming unit reforms the mixed gas of the raw fuel and the steam generated in the evaporating unit to generate a reformed gas, and sends the reformed gas to the fuel cell stack. The heat exchange unit raises the temperature of the oxidant gas, and sends the heated oxidant gas to the fuel cell stack. The combustion unit burns unreacted reformed gas discharged from the fuel cell stack, and generates heat to be transmitted to the evaporation unit, the reforming unit, the heat exchange unit, and the fuel cell stack. The evaporation unit, the reforming unit, and the heat exchange unit are stacked, and the combustion unit is disposed adjacent to the evaporation unit, the reforming unit, and the heat exchange unit.

  According to such a configuration, the heat generated in the combustion unit is directly transmitted not only to the evaporation unit, the reforming unit, but also to the heat exchange unit, and the oxidant gas is the heat directly received from the combustion unit. Is warmed. Therefore, the power generation efficiency of the fuel cell stack can be improved as compared with the conventional configuration in which the oxidant gas is warmed by the heat indirectly received from the combustion unit.

In addition, the evaporation portion, the reforming portion, and the heat exchange portion may be formed in a shape that annularly surrounds the periphery of the combustion portion.
According to such a configuration, it is possible to suppress the deviation of the amount of heat that escapes from the combustion section, and thus it is possible to make it difficult to cause damage due to distortion of the fuel cell reforming unit.

Moreover, the evaporation part may be arrange | positioned at the lowest step.
In the evaporation section, it is sufficient to receive heat at least at a temperature at which water can be evaporated, but in the reforming section, a high temperature (for example, 800 ° C.) is required for the reforming reaction, and the reforming section and heat From the exchange unit, it is necessary to send a reformed gas or an oxidant gas warmed to a high temperature to the fuel cell stack. Since the temperature in the combustion unit is higher toward the upper side, according to the configuration in which the evaporation unit is disposed at the lowermost stage, the power generation efficiency of the fuel cell stack can be improved as compared with the configuration in which the evaporation unit is disposed other than the lowermost stage. .

In addition, the bottom of the evaporation portion may be formed to be inclined upward from the inside toward the outside of the combustion portion.
According to such a configuration, the water that has entered the evaporation section flows toward the high temperature combustion section, so that the evaporation performance of the water can be enhanced.

In addition, the reforming section is disposed in the upper stage of the evaporation section, and the boundary that forms the boundary between the reforming section and the evaporation section is formed to be inclined upward from the inside to the outside, which is the side of the combustion section. May be
According to such a configuration, since the boundary between the reforming unit and the evaporating unit is inclined, the reforming catalyst requiring high heat can be brought closer to the combustion unit on the high temperature side. Therefore, the fuel cell reforming unit can send a reformed gas of good quality to the fuel cell stack.

Further, the combustion unit may release the exhaust gas obtained by burning the reformed gas and the oxidant gas so as to spread over the entire lower surface of the fuel cell stack below the lower surface of the fuel cell stack.
According to such a configuration, the entire fuel cell stack is uniformly covered with less deviation of the temperature distribution by the exhaust gas spread over the entire lower surface of the fuel cell stack, and the heat retaining effect of the fuel cell stack is enhanced. Therefore, the power generation efficiency of the fuel cell stack can be improved.

  In addition, a casing that encloses the heat insulating body so as to form an exhaust gas venting space between the heat insulating body and the heat insulating body covering the entire fuel cell stack, the evaporation portion, the reforming portion, the heat exchange portion, and the combustion portion. And may be provided. Then, from the gas vent provided in the heat insulator to the exhaust port provided in the housing via the exhaust gas ventilating space, a discharge route may be formed for discharging the exhaust gas to the outside.

  According to such a configuration, since the fuel cell stack is encased in the exhaust gas in the heat insulating material, a reduction in power generation efficiency is suppressed. In addition, since the exhaust gas passes through the exhaust route around the heat insulating material, the entire heat insulating material is also covered with the exhaust gas, so that the heat retaining effect is further enhanced. Therefore, it is possible to suppress the decrease in the temperature of the fuel cell stack and to suppress the decrease in the power generation efficiency.

FIG. 1A is a perspective view of a fuel cell module. FIG. 1 (B) is a plan view of the fuel cell module. FIG. 2 is a perspective view when the housing of the fuel cell module is removed. About a heat insulating material, a mode that it cut | disconnected in the cross section of II-II of FIG. FIG. 3A is a cross-sectional view of the fuel cell module, which is a cross-sectional view taken along the line IIIA-IIIA of FIG. FIG. 3B is a cross-sectional view of the fuel cell module, which is a cross-sectional view taken along the line IIIB-IIIB of FIG.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 2, FIG. 3 (A) and FIG. 3 (B), the fuel cell module 1 of the present embodiment has stacked a plurality of fuel cells that generate electric power by the electrochemical reaction between the reformed gas and the oxidant gas. A fuel cell stack 9 is provided inside.

  The fuel cell module 1 includes a casing 2 formed in a cylindrical shape as a whole, as shown in FIGS. 1 (A) and 1 (B). Then, as shown in FIG. 3A and the like, a first supply pipe 312 and a second supply pipe 332 for introducing water or the like into the fuel cell module 1 are pierced on the side surface of the housing 2. And its end is outside.

  Further, as shown in FIG. 2 and the like, the fuel cell module 1 is provided with a main body portion 3 having a burning portion 30 and the like described later inside the housing 2. The fuel cell stack 9 is mounted on the main body 3. The first supply pipe 312 and the second supply pipe 332 are extended from the main body 3.

  As shown in FIG. 3 (A) and FIG. 3 (B), the main body 3 folds or welds a sheet metal, etc., and thereby the combustion unit 30, the evaporation unit 31, the reforming unit 32, and the heat exchange The respective functional parts of the part 33 and the heat discharge space 34 are assembled to be formed.

The combustion unit 30 is formed in a cylindrical shape, and a plurality of exhaust gas holes 302 are formed on the upper side surface thereof.
The evaporation unit 31, the reforming unit 32, the heat exchange unit 33, and the heat discharge space 34 are formed in a shape that annularly surrounds the combustion unit 30. A wall surface (outer peripheral surface) of the combustion unit 30 is used as an inner wall surface of the evaporation unit 31, the reforming unit 32, the heat exchange unit 33, and the heat discharge space 34 on the combustion unit 30 side.

  Among these, the bottom portion 319 of the evaporation portion 31 and the boundary portion 329 forming the boundary between the evaporation portion 31 and the reforming portion 32 are from the inside which is the combustion portion 30 side to the outside which is the opposite side. It is formed in the shape which inclines toward. The boundary portion 329 is formed with a plurality of passage holes 328 through which water vapor passes.

A first supply pipe 312 is connected to the evaporation unit 31. A mixture of city gas and water, which is a raw fuel, is externally supplied into the evaporation section 31 through the first supply pipe 312.
When the mixture is supplied to the evaporation unit 31, the mixture is warmed by the heat received from the combustion unit 30, and the water turns into water vapor. Then, the mixed gas in which water is turned into water vapor among the mixture is sent to the reforming unit 32 through the passage hole 328 provided in the boundary portion 329.

  The reforming unit 32 is filled with a reforming catalyst (not shown). Further, a second pipe 321 is connected to the reforming unit 32 (see FIG. 3B). The second pipe 321 is a pipe for supplying the fuel cell stack 9 with the reformed gas.

  When the mixed gas is supplied from the evaporation unit 31 to the reforming unit 32, the mixed gas is reformed by the catalyst activated by the heat received from the combustion unit 30, and a reformed gas is generated. The reformed gas is also warmed by the heat received from the combustion unit 30.

Then, the heated reformed gas is supplied to the fuel cell stack 9 via the second pipe 321.
The third pipe 331 and the second supply pipe 332 are connected to the heat exchange unit 33 (see FIG. 3A). Air, which is an oxidant gas, is supplied from the outside into the heat exchange unit 33 via the second supply pipe 332. Then, the oxidant gas is warmed by the heat received from the combustion unit 30 to raise its temperature, and is supplied to the fuel cell stack 9 through the third pipe 331.

  The first pipe 301 is connected to the combustion unit 30 (see FIG. 3B). The first pipe 301 is a pipe for supplying the (non-reacted) reformed gas which has not been used for power generation from the fuel cell stack 9 to the combustion unit 30, and the reformed gas is supplied from the fuel cell stack 9 to the evaporation unit 31. I'm leading to the bottom.

  The combustion unit 30 mixes the reformed gas received from the fuel cell stack 9 via the first pipe 301 with the air taken from the outside and burns the mixture internally. Then, the combustion unit 30 discharges the exhaust gas generated by the combustion from the exhaust gas holes 302 into the heat discharge space 34. The exhaust gas hole 302 is provided on the entire peripheral side surface of the portion of the portion located in the heat discharge space 34 of the combustion unit 30.

  The heat discharge space 34 forms an annular space having an upper surface parallel to the lower surface of the fuel cell stack 9. The heat exhaust space 34 is disposed at the top of the main body 3, and the fuel cell stack 9 is placed on the upper portion of the main body 3.

  The heat insulator 4 is formed in a size to cover the entire assembled body 3 and fuel cell stack 9. The heat insulator 4 forms a heat insulating space 49 between the main body 3 and the fuel cell stack 9. A gas venting hole 40 is formed at the center of the upper surface of the heat insulator 4.

The housing 2 is formed in a size capable of covering the heat insulator 4 surrounding the main body 3 and the fuel cell stack 9 so as to form an exhaust gas venting space 39 with the heat insulator 4. There is.
Further, on the lower surface of the housing 2, an exhaust port 42 is formed in which the exhaust gas ventilating space 39 is open to the external space.

  A discharge route for discharging the exhaust gas in the heat insulating space 49 between the housing 2 and the heat insulating body 4 by the exhaust gas venting space 39 and the exhaust port 42, and from the gas venting hole 40 via the exhaust gas venting space 39 A discharge route leading to the discharge port 42 is formed.

When the exhaust gas is discharged from the exhaust gas hole 302 of the combustion unit 30, the exhaust gas is discharged so as to spread over the entire lower surface of the fuel cell stack 9 under the lower surface of the fuel cell stack 9.
Thereafter, the exhaust gas discharged from the exhaust gas holes 302 is discharged from the heat discharge holes 341 provided in the heat discharge space 34 into the adiabatic space 49 surrounded by the heat insulator 4.

  Therefore, the exhaust gas discharged from the exhaust gas hole 302 of the combustion unit 30 is discharged into the heat discharge space 34 and then discharged and filled into the heat insulation space 49 of the heat insulator 4 and thereafter the discharge route from the gas vent hole 40 Through the discharge port 42 to the outside.

The fuel cell module 1 configured as described above has the following characteristic effects.
The fuel cell module 1 according to the embodiment uses the side surfaces around the combustion unit 30 as the inner wall surfaces of the evaporation unit 31, the reforming unit 32, and the heat exchange unit 33 to form the evaporation unit 31, the reforming unit 32, And, since they constitute the heat exchange section 33, they are disposed adjacent to the combustion section 30.

Therefore, heat is directly transmitted from the combustion unit 30 to the evaporation unit 31, the reforming unit 32, and the heat exchange unit 33 without taking heat on the way.
Therefore, when the fuel cell module 1 is used, the oxidant gas is warmed by the heat directly received from the combustion unit 30. Therefore, compared with the conventional configuration in which the oxidant gas is warmed by the heat lower than this temperature The power generation efficiency of the stack 9 can be improved.

  Further, in the fuel cell module 1 according to the above-described embodiment, the evaporator 31, the reformer 32, and the heat exchanger 33 surround the combustion unit 30 in a ring shape. If the amount of heat escaping from the combustion unit 30 is uneven, distortion easily occurs in the unit (fuel cell reforming unit) that constitutes the combustion unit 30, the evaporation unit 31, the reforming unit 32, and the heat exchange unit 33. According to the configuration of the above embodiment, the amount of heat escaping from the combustion unit 30 is less likely to be uneven. Therefore, it is possible to reduce the possibility that the fuel cell reforming unit is broken due to the strain.

Further, in the fuel cell module 1 of the above-described embodiment, the evaporation unit 31 is disposed at the lowermost stage.
The evaporator 31 may receive heat at a temperature at which the water can be evaporated at least, but the reformer 32 needs a high temperature (for example, 800 degrees) for the reforming reaction, and the reformer It is necessary to send reformed gas and oxidant gas warmed to a high temperature to the fuel cell stack 9 from the heat exchanger 32 and the heat exchanger 33.

  Since the temperature in the combustion unit 30 is higher toward the upper side, according to the configuration in which the evaporation unit 31 is disposed in the lowermost stage, the power generation efficiency of the fuel cell stack 9 is higher than in the configuration in which the evaporation unit 31 is disposed other than the lowermost stage. It can be improved.

  Further, in the fuel cell module 1 according to the above-described embodiment, the bottom of the evaporation unit 31 is formed to be inclined while rising from the inside toward the combustion unit 30 toward the outside. Therefore, the water that has entered the evaporation unit 31 flows toward the high temperature combustion unit 30 side, and the evaporation performance is improved.

  Further, in the fuel cell module 1 of the above embodiment, the reforming unit 32 is disposed on the upper stage of the evaporating unit 31, and the boundary 329 forming the boundary between the evaporating unit 31 and the reforming unit 32 is on the combustion unit 30 side. It is formed in the shape which inclines, rising from inner side outward.

  As described above, since the boundary 329 between the evaporation unit 31 and the reforming unit 32 is inclined, a larger amount of the reforming catalyst requiring high heat for activation can be brought closer to the high temperature combustion unit 30. it can.

Therefore, the fuel cell module 1 can send a reformed gas of good quality to the fuel cell stack 9.
In addition, the fuel cell module 1 of the above embodiment includes the fuel cell stack 9, the evaporation unit 31, the reforming unit 32, the heat exchange unit 33, and the casing 2 capable of covering the entire combustion unit 30. The combustion unit 30 releases exhaust gas under the lower surface of the fuel cell stack 9.

  The fuel cell stack 9 is heated by the combustion unit 30 via the top surface (the top surface of the main body 3) forming the heat discharge space 34. However, if the temperature distribution around the fuel cell stack 9 is biased, for example, the temperature distribution of the fuel cell stack 9 may also be biased to correspond to the bias.

  Therefore, according to the above-described embodiment, the exhaust gas is discharged under the lower surface of the fuel cell stack 9 so as to spread over the entire lower surface of the fuel cell stack 9. The whole is uniformly covered with less deviation of temperature distribution, and the temperature of the fuel cell stack 9 is maintained.

Therefore, the fuel cell module 1 can further improve the power generation efficiency of the fuel cell stack 9.
Further, in the fuel cell module 1 of the above embodiment, the whole of the fuel cell stack 9, the evaporating unit 31, the reforming unit 32, the heat exchanging unit 33, and the burning unit 30 is covered with the heat insulator 4. The casing 2 encloses the heat insulator 4 so as to form an exhaust gas venting space 39 with the heat insulator 4.

  As a result, the inside of the thermal insulation space 49 surrounded by the thermal insulator 4 is directed from the gas venting hole 40 provided at the top of the thermal insulator 4 to the exhaust port 42 provided at the bottom of the housing 2 via the exhaust gas ventilating space 39. An exhaust route for exhausting the exhaust gas of the

According to such a configuration, the fuel cell stack 9 is covered with the exhaust gas in the heat insulator 4, the temperature of the fuel cell stack 9 is maintained, and the reduction in the power generation efficiency is suppressed.
In addition, since the fuel cell module 1 is provided with a discharge route around the heat insulator 4, the entire heat insulator 4 is also covered with the exhaust gas, so the heat retention effect is further enhanced.

Therefore, according to the fuel cell module 1, the temperature of the fuel cell stack 9 can be more reliably maintained, and the reduction in the power generation efficiency can be further reliably suppressed.
Further, the main body portion 3 constituting the fuel cell module 1 of the present embodiment is formed by welding a plate material so that the combustion portion 30 becomes a wall surface of the evaporation portion 31, the reforming portion 32, and the heat exchange portion 33. It has a very simple structure.

Therefore, the fuel cell module 1 can be manufactured inexpensively and easily.
[Other embodiments]
As mentioned above, although embodiment was described, it can not be overemphasized that the invention described in the claim can take various forms, without being limited to the above-mentioned embodiment.

(1) The fuel cell module 1 described in the above embodiment is merely an example, and the present invention is not limited to this.
(2) In the said embodiment, although the fuel cell module 1 formed in cylindrical shape was illustrated, it is not restricted to this.

(3) In the above embodiment, city gas is used as the raw fuel, but the raw fuel is not limited to this.
(4) Although air is used as the oxidant gas in the above embodiment, the oxidant gas is not limited to this.

  (5) Although the heat insulator 4 is used in the above embodiment, as the heat insulator 4, a material known as a heat insulator may be used as a material, but any material having a heat insulation effect can be used. Such a thing may be used, for example, a sheet metal may be used.

  (6) In the above embodiment, only the reformed gas is sent from the fuel cell stack 9 to the combustion unit 30, but for example, a raw fuel or an oxidant gas may be sent.

DESCRIPTION OF SYMBOLS 1 ... Fuel cell module 2 ... Housing | casing 3 ... Main body part 4 ... Thermal insulation 9 ... Fuel cell stack 30 ... Combustion part 31 ... Evaporation part 32 ... Reforming part 33 ... Heat exchange part 34 ... Heat discharge space 39 ... Exhaust gas ventilation space DESCRIPTION OF SYMBOLS 40 ... Gas removal hole 42 ... Discharge port 49 ... Heat insulation space 301 ... 1st pipe 302 ... Exhaust gas hole 312 ... 1st supply pipe 319 ... Bottom part 321 ... 2nd pipe 328 ... Passage hole 329 ... Boundary part 331 ... 3rd pipe 332 ... Second supply pipe 341 ... Heat exhaust hole.

Claims (7)

A fuel cell reforming unit for forming a fuel cell module together with a fuel cell stack in which a plurality of fuel cells that generate electric power by an electrochemical reaction between a reformed gas and an oxidant gas are stacked,
An evaporation unit that generates water vapor,
A reforming unit that reforms mixed gas of raw fuel and steam generated in the evaporation unit to generate the reformed gas, and sends the reformed gas to the fuel cell stack;
A heat exchange unit that raises the temperature of the oxidant gas and sends the temperature of the oxidant gas to the fuel cell stack;
And a combustion unit for burning the unreacted reformed gas discharged from the fuel cell stack and generating heat to be transmitted to the evaporation unit, the reforming unit, the heat exchange unit, and the fuel cell stack. Equipped
The evaporation unit, the reforming unit, and the heat exchange unit are stacked, and the combustion unit is disposed adjacent to the evaporation unit, the reforming unit, and the heat exchange unit .
A reforming unit for a fuel cell , wherein the evaporating unit, the reforming unit, and the heat exchanging unit are formed in a ring shape surrounding the periphery of the combustion unit. In the fuel cell reforming unit according to claim 1 ,
The reforming unit is disposed at the lowermost stage. The fuel cell reforming unit according to any one of claims 1 to 2 .
A reforming unit for a fuel cell, wherein a bottom portion of the evaporation portion is formed to be inclined upward from the inside toward the outside of the combustion portion. The fuel cell reforming unit according to any one of claims 1 to 3 .
The reforming unit is disposed in the upper stage of the evaporation unit.
A fuel cell reforming device, wherein a boundary portion forming a boundary between the reforming portion and the evaporation portion is formed to be inclined upward from the inside toward the outside, which is the side of the combustion portion. unit. In the fuel cell reforming unit according to any one of claims 1 to 4 ,
The combustion unit is
A reformer unit for a fuel cell, which discharges an exhaust gas obtained by burning the reformed gas and the oxidant gas under the lower surface of the fuel cell stack so as to spread over the entire lower surface of the fuel cell stack. . In the fuel cell reforming unit according to claim 5 ,
A heat insulator covering the entire fuel cell stack, the evaporation unit, the reforming unit, the heat exchange unit, and the combustion unit;
A housing enclosing the heat insulator to form an exhaust gas venting space between the heat insulator and the heat insulator;
Equipped with
A fuel cell is characterized in that a discharge route for discharging the exhaust gas to the outside is formed from the degassing hole provided in the heat insulator to the discharge port provided in the casing via the exhaust gas ventilating space. For reforming unit. A fuel cell reforming unit according to any one of claims 1 to 6 ,
A fuel cell module comprising: the fuel cell stack.