JP7299802B2 - Combustor and fuel cell module - Google Patents

Description

The present invention relates to combustors and fuel cell modules.

2. Description of the Related Art Conventionally, in a fuel cell module that generates power by reacting a fuel gas and an oxidant gas, a configuration is known in which residual fuel gas that has not been used for power generation in fuel cells is used as fuel in a combustor.

For example, Patent Literature 1 discloses, as a configuration of a combustor in such a fuel cell module, a fuel passage pipe for ejecting residual fuel gas not used in the fuel cell from its tip, and an oxygen gas pipe above the fuel passage pipe. A combustor is disclosed that includes a separation wall that directs contained gases up a fuel line tube.

JP 2018-169080 A

However, in the configuration described in Patent Document 1, the oxidant-containing gas is guided above the combustion passage pipe at a steep angle by the separation wall, so the flow velocity of the guided oxygen-containing gas is high, and combustion in the combustor is suppressed. There is a problem of instability.

SUMMARY OF THE INVENTION An object of the present invention is to provide a combustor capable of achieving stable combustion.

The combustor of the present invention is supplied with residual fuel gas and oxidant gas that have not been used in the power generation reaction in the fuel cell, and is a combustor for combusting the residual fuel gas together with the oxidant gas. and a fuel gas ejection portion for ejecting residual fuel gas from the fuel gas ejection port at the upper end, the oxidizing gas is ejected at the same height as or below the fuel gas ejection port, and the oxidizing gas is ejected from the fuel gas ejection portion. It is characterized in that it is guided along the side wall.

According to the present invention having the above configuration, the oxidant gas is guided in a direction along the side wall of the fuel gas ejection portion, so that the oxidant gas can be prevented from being directly blown onto the flame of the fuel gas ejection portion, and the fuel gas is stabilized. combustion is achieved.

In the present invention, preferably, an oxidant gas is supplied to the internal space, and an oxidant gas guide part for guiding the supplied oxidant gas is further provided, the oxidant gas guide part forming a fuel gas ejection part. Guide the oxidant gas toward the sidewall.

According to the present invention having the above configuration, the oxidant gas guided by the oxidant gas guide portion collides with the fuel gas ejection portion and then flows along the side wall of the fuel gas ejection portion. This makes it possible to guide the oxidant gas along the side wall of the fuel gas ejection portion.

Further, in the present invention, preferably, the opening area of the oxidizing gas ejection port through which the oxidizing gas is ejected from the internal space is larger than the opening area of the fuel gas ejection port.
According to the present invention configured as described above, a sufficient amount of oxidant gas is supplied, so that stable combustion is realized.

Further, in the present invention, preferably, the ejected oxidant gas is residual oxidant gas that has not been used in the power generation reaction in the fuel cell.
According to the present invention having the above configuration, there is no need to newly provide a configuration (such as a pipe) for supplying the oxidant gas from the outside.

Further, in the present invention, preferably, the residual fuel gas supplied to the fuel gas ejection portion is not premixed with the residual fuel gas that has not been used in the power generation reaction in the fuel cell.
According to the present invention having the above configuration, since the fuel gas is jetted from the fuel gas jetting port in a state of high concentration, more stable combustion is realized.

In the present invention, preferably, the fuel gas ejection portion is provided with a plurality of fuel gas ejection ports arranged in a row.
According to the present invention having the above configuration, it is possible to realize uniform combustion in the row direction, and more efficiently utilize the heat generated in the combustor for heating the reformer and the like.

The fuel cell module of the present invention comprises a fuel cell, the combustor for combusting the residual fuel gas not used in the power generation reaction in the fuel cell together with the oxidant gas, and the combustor disposed above the combustor. a reformer that reforms the raw fuel gas with the heat of combustion to generate the fuel gas to be supplied to the fuel cell.
According to the present invention having the above configuration, stable combustion is realized in the combustor, so that the raw fuel gas can be reliably reformed in the reformer.

Preferably, the present invention further comprises a housing containing the combustor and the reformer, and the fuel cell is arranged outside the housing independently of the housing.
According to the present invention configured as described above, the thermal effect of the combustor on the fuel cell can be reduced.

ADVANTAGE OF THE INVENTION According to this invention, the combustor which can implement|achieve stable combustion can be provided.

1 is a diagram showing a schematic configuration of a fuel cell module according to a first embodiment of the invention; FIG. FIG. 2 is a vertical sectional view of a reformer/heater of the fuel cell module shown in FIG. 1; FIG. 2 is a perspective view showing a combustor of the fuel cell module shown in FIG. 1; FIG. 2 is an exploded perspective view showing a combustor of the fuel cell module shown in FIG. 1; FIG. 4 is a vertical sectional view showing the flow of residual fuel gas and residual oxidant gas in the combustor of the fuel cell module according to the first embodiment of the present invention; FIG. 6 is a vertical cross-sectional view of a reformer/heater for a fuel cell module according to a second embodiment of the present invention; FIG. 7 is a perspective view showing a combustor of the fuel cell module shown in FIG. 6; FIG. 7 is an exploded perspective view showing a combustor of the fuel cell module shown in FIG. 6; FIG. 6 is a vertical sectional view showing the flow of residual fuel gas and residual oxidant gas in the combustor of the fuel cell module according to the second embodiment of the present invention;

<First embodiment>
Hereinafter, a fuel cell module according to a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a fuel cell module according to a first embodiment of the invention. In FIG. 1, the flow of fuel gas (including raw fuel gas and residual fuel gas) is indicated by a dashed line, the flow of air (including residual oxidant gas) is indicated by a solid line, and the flow of exhaust gas is indicated by a dashed line. show.
As shown in FIG. 1, a fuel cell module 1 according to an embodiment of the present invention includes a fuel cell stack 2 that performs a power generation reaction, a fuel gas obtained by reforming raw fuel gas, and a heating and a fluid supply device 4 for supplying air, which is an oxidant gas. The fluid supply device 4 is composed of an evaporator 4a and a reformer/heater 4b.

A water supply pipe 20 for supplying water, a raw fuel gas supply pipe 22 for supplying raw fuel gas, and an exhaust gas discharge pipe 23 for discharging exhaust gas are connected to the evaporator 4a. ing. The evaporator 4a also includes an exhaust gas pipe 26 for supplying exhaust gas from the housing 6 of the reformer/heater 4b to the evaporator 4a, and a mixed gas conduit for supplying a mixed gas from the evaporator 4a to the reformer 10. 28 are connected.

The evaporator 4a evaporates the water supplied from the water supply pipe 20 by the heat of the exhaust gas supplied through the exhaust gas pipe 26 to generate steam, and supplies this steam from the raw fuel gas supply pipe 22. It is configured to be mixed with the raw fuel gas supplied. The raw fuel gas mixed with steam in the evaporator 4 a is supplied to the reformer 10 through the mixed gas conduit 28 . The exhaust gas that has heated the water is discharged to the outside through the exhaust gas discharge pipe 23 .

The reformer/heater 4 b has a housing 6 , which is arranged vertically above the fuel cell stack 2 . The fuel cell stack 2 and the housing 6 are surrounded by a heat insulating material 8, and the heat insulating material 8 is also provided between the fuel cell stack 2 and the housing 6, so that the fuel cell stack 2 is thermally isolated from housing 6 (fluid supply device 4). The heat insulating material 8 surrounding the fuel cell stack 2 and the housing 6 constitutes the outermost surface of the fuel cell module 1. Even if a metal container or the like covering the outside of the heat insulating material 8 is provided, Good, but need not be provided. A reformer 10 and a combustor 12 are accommodated in a space sealed by the housing 6 .

The housing 6 has a double wall structure, and an air flow path 6A is formed between the inner wall and the outer wall. An air supply pipe 24 is connected to the top surface of the housing 6 , and air as an oxidant gas is supplied from the outside through the air supply pipe 24 . The air (oxidant gas) supplied to the air flow path 6A is heated by the combustion heat of the combustor 12 while flowing through the air flow path 6A. The air heated in the air flow path 6A is supplied to the fuel cell stack 2 through the oxidant gas supply passage 32 .

A fuel supply passage 30 is provided between the reformer/heater 4b and the fuel cell stack 2 to supply the fuel gas from the reformer 10 to the fuel cell stack 2. An oxidant gas supply passage 32 is provided for supplying heated air to the fuel cell stack 2 . Between the reformer/heater 4b and the fuel cell stack 2, there is a fuel discharge passage for supplying the combustor 12 with residual fuel gas, which is off-gas that has not been used for power generation in the fuel cell stack 2. 34 and an oxidant gas discharge passage 36 for supplying the combustor 12 with the oxidant gas that has not been used for power generation in the fuel cell stack 2 .

The reformer 10 is filled with a reforming catalyst (not shown), and the raw fuel gas mixed with steam is supplied from the evaporator 4 a through the mixed gas conduit 28 . It is configured to steam reform the fuel gas to produce a hydrogen-rich fuel gas. The fuel gas produced in the reformer 10 is sent to the fuel cell stack 2 and used in the fuel cell stack 2 for power generation. This fuel gas is supplied to the fuel cell stack 2 through a fuel supply passage 30 extending between the reformer 10 and the fuel cell stack 2 . Here, since the reformer 10 is housed in the housing 6 and the housing 6 is surrounded by the heat insulating material 8, the fuel supply passage 30 for supplying the fuel gas passes through the housing 6 and the heat insulating material 8 to supply the fuel. It extends to the battery cell stack 2 .

The combustor 12 is configured to combust residual fuel gas and residual air left in the fuel cell stack 2 without being used for power generation. Fuel remaining in the fuel cell stack 2 without being used for power generation is discharged to the combustor 12 through a fuel discharge passage 34 extending between the combustor 12 and the fuel cell stack 2 . This fuel discharge passage 34 also extends from the fuel cell stack 2 to the combustor 12 through the housing 6 and the heat insulator 8 . Residual fuel discharged to combustor 12 is combusted by combustor 12 to heat reformer 10 disposed above combustor 12 . As a result, a reforming catalyst (not shown) in the reformer 10 is heated to a temperature at which steam reforming is possible.

On the other hand, air, which is an oxidant gas for power generation, is also supplied to the housing 6 from the outside through the air supply pipe 24, and is heated by the combustion heat of the combustor 12 while passing through the air flow path 6A. It is supplied to the battery cell stack 2 . The air for power generation heated in the fluid supply device 4 is supplied to the fuel cell stack 2 through the oxygen-containing gas supply passage 32 extending from the housing 6 . This oxygen-containing gas supply passage 32 also penetrates the heat insulating material 8 surrounding the housing 6 and extends from the housing 6 to the fuel cell stack 2 .

The fuel cell stack 2 is a flat plate cell stack, and is configured by stacking a plurality of rectangular flat plate fuel cells. The fuel cell stack 2 is independently provided outside the housing 6 . Each fuel cell is constructed by providing a fuel electrode and an air electrode (oxidant gas electrode) on both sides of a flat electrolyte made of an oxide ion conductor. is placed a separator. A fuel gas and an oxidant gas are supplied to each fuel cell through a fuel supply passage 30 and an oxidant gas supply passage 32, and power generation is performed by the fuel cell.

The residual fuel gas supplied to the fuel cell stack 2 and left without being used for power generation is discharged to the combustor 12 through the fuel discharge passage 34 as described above. Also, the remaining air that has been supplied to the fuel cell stack 2 and has not been used for power generation is discharged to the combustor 12 through the oxidant gas discharge passage 36 . This oxidant gas discharge passage 36 also penetrates the heat insulating material 8 surrounding the housing 6 and extends from the fuel cell stack 2 to the combustor 12 . The residual air discharged to combustor 12 is used for combustion in combustor 12 . Combustion gas generated by combustion is discharged to the evaporator 4a through an exhaust gas pipe 26 as exhaust gas. The exhaust gas discharged to the evaporator 4a is discharged to the outside through an exhaust gas discharge pipe 23 after being used to evaporate water.

Next, the configuration of the combustor 12 in this embodiment will be described. 2 is a vertical sectional view of the reformer/heater of the fuel cell module shown in FIG. 1. FIG. 3 and 4 show the combustor of the fuel cell module shown in FIG. 1, FIG. 3 being a perspective view, and FIG. 4 being an exploded perspective view. 2 to 4, the air flow path 6A (outer wall) of the housing 6 is omitted, and only the bottom portion of the housing is shown in FIGS.
As shown in FIGS. 2 to 4, the combustor 12 consists of a manifold for ejecting residual fuel gas and residual oxidant gas. 42 and a second combustor-forming member 44 . The bottom surface 6a of the housing 6 is formed with an oxidizing gas opening 6B to which the oxidizing gas discharge passage 36 is connected, and a fuel opening 6C to which the fuel discharge passage 34 is connected.

The first combustor-forming member 42 has a rectangular flat plate portion 42A and a tubular portion 42B erected downward from the flat plate portion 42A. The tubular portion 42B is connected to an opening formed in the center of the flat plate portion 42A. Note that the tubular portion 42B of the first combustor forming member 42 forms part of the fuel discharge passage 34 .

The second combustor forming member 44 includes a flat rectangular annular edge portion 49 , an oxidizing gas guide portion 46 protruding upward from the edge portion 49 , and a central portion in the width direction of the oxidizing gas guide portion 46 . and a fuel gas ejection portion 48 formed to extend in the longitudinal direction.
The edge portion 49 is flat and has an outer shape substantially equal to the bottom surface 6 a of the housing 6 .

The oxidizing gas guide portion 46 has a side wall portion 46A that is rectangular in plan view and extends upward inside the edge portion, and a flat plate portion 46B that closes the upper side of the side wall portion 46A. Corners between the side wall portion 46A and the flat plate portion 46B are curved and chamfered. Oxidant gas ejection portions 47 are formed on both sides of the flat plate portion 46B in the width direction so as to protrude upward. The oxidant gas ejection portion 47 is a portion that protrudes upward in a rectangular shape from the flat plate portion 46B. The oxidizing gas ejection part 47 has an open portion facing the fuel gas ejection part 48 on the central side, and an oxidizing gas ejection port 47A is formed. In this embodiment, a plurality of (five) oxidant gas ejection portions 47 are provided on both sides of the fuel gas ejection portion 48 so as to be aligned at regular intervals in the longitudinal direction.

The fuel gas ejection portion 48 includes a side wall portion 48A projecting upward from the flat plate portion 46B of the oxidizing gas guide portion 46, and a top surface portion 48B closing the upper side of the side wall portion 48A. The fuel gas ejection portion 48 extends substantially over the entire length of the interior space of the housing 6 in the longitudinal direction. The side wall portion 48A is formed in an elongated annular shape extending in the longitudinal direction. The side wall portion 48A stands vertically with respect to the flat plate portion 46B. The top surface portion 48B is formed with circular openings arranged in a line in the center in the width direction. A cylindrical side wall portion 48D is formed around the periphery of each opening, and a fuel gas ejection port 48C is formed at the upper end of the cylindrical side wall portion 48D. The fuel gas ejection ports 48C are provided at regular intervals in the longitudinal direction.

A cylindrical side wall portion 48D is formed around the periphery of each fuel gas ejection port 48C. Note that the side wall portion 48A of the fuel gas ejection portion 48 is vertical in this embodiment.

The second combustor forming member 44 is arranged such that the edge portion 49 contacts the bottom surface 6a of the housing 6, and the edge portion 49 and the bottom surface 6a of the housing 6 are welded. Further, the first combustor forming member 42 is arranged such that the tubular portion 42B penetrates the fuel opening 6C in the bottom surface 6a of the housing 6. As shown in FIG. Furthermore, the flat plate portion 42A of the first combustor forming member 42 is welded around the fuel gas ejection portion 48 of the flat plate portion 46B of the second combustor forming member 44 .

With such a configuration, an oxidant gas supply space 50 is formed as an internal space between the bottom surface 6 a of the housing 6 and the oxidant gas guide portion 46 of the second combustor forming member 44 . The oxidant gas supply space 50 communicates with the oxidant gas discharge passage 36 through the oxidant gas opening 6B in the bottom surface 6a. Also, the oxidant gas supply space 50 communicates with the internal space of the housing 6 through the oxidant gas ejection port 47A. The opening area (total opening area) of the oxidant gas ejection port 47A is larger than the opening area (total opening area) of the fuel gas ejection port 48C. In the present embodiment, residual oxidant gas that has not been used for power generation in the fuel cell stack 2 is supplied to the oxidant gas supply space 50 via the oxidant gas discharge passage 36, but this is not the only option. It is also possible to supply the oxidant gas directly from the outside without needing to do so.

A fuel gas supply space 52 is formed between the flat plate portion 42A of the first combustor forming member 42 and the fuel gas ejection portion 48 of the second combustor forming member 44 . The fuel gas supply space 52 communicates with the fuel discharge passage 34 . Further, the fuel gas supply space 52 communicates with the internal space of the housing 6 through the fuel gas ejection port 48C. The fuel gas ejection portion 48 extends upward with respect to the flat plate portion 46B of the oxidant gas guide portion 46, and the fuel gas ejection port 48C at the upper end is positioned above the oxidant gas ejection port 47A. .

As a whole, the first combustor forming member 42 and the second combustor forming member 44 have a symmetrical configuration with the center in the width direction as a plane of symmetry. The fuel gas ejection ports 48C are arranged in a row along the plane of symmetry. In this embodiment, the fuel gas ejection ports 48C are arranged in a row along the plane of symmetry, but they may be arranged in a row along a zigzag line, for example. In short, the term "single row" in this embodiment refers to a state in which a plurality of fuel gas injection ports are not positioned within the same cross section in the width direction.

FIG. 5 is a vertical sectional view showing the flow of residual fuel gas and residual oxidant gas in the combustor of the fuel cell module according to the first embodiment of the present invention. Residual fuel gas that has not been used for power generation in the fuel cell stack 2 is supplied to the fuel gas supply space 52 through the fuel discharge passage 34 . As shown in FIG. 5, the residual fuel gas supplied to the fuel gas supply space 52 is jetted vertically upward into the internal space of the housing 6 from the fuel gas jetting port 48C at the upper end of the fuel gas jetting portion 48.

On the other hand, residual oxidant gas that has not been used for power generation in the fuel cell stack 2 is supplied to the oxidant gas supply space 50 through the oxidant gas discharge passage 36 . The residual oxidant gas supplied to the oxidant gas supply space 50 through the oxidant gas discharge passage 36 collides with the flat plate portion 42A of the first combustor forming member 42 and flows outward in the horizontal direction. Then, the oxidant gas is sent to the oxidant gas ejection portion 47 by the side wall portion 46A and the flat plate portion 46B of the oxidant gas guide portion 46 . Then, the oxidant gas is guided by the oxidant gas ejection portion 47 and ejected from the oxidant gas ejection port 47A toward the side wall portion 48A of the fuel gas ejection portion 48 into the internal space of the housing 6 . The residual oxidant gas ejected from the oxidant gas ejection port 47A toward the side wall portion 48A of the fuel gas ejection portion 48 collides with the side wall portion 48A. Then, the residual oxidant gas is guided upward along the side wall portion 48A. The flow velocity of the residual oxidizing gas flowing along the side wall portion 48A can be adjusted by a method such as changing the opening area of the oxidizing gas ejection port 47A.

The residual fuel gas ejected in this manner is ignited by an ignition device (not shown) and combusted together with the residual oxidant gas. Combustion heat generated by burning the residual fuel gas heats the reformer 10 and also heats the air flowing through the air flow path 6A of the housing 6 .

As described above, according to the first embodiment, the following effects are achieved.
According to this embodiment, the residual oxidant gas is ejected below the fuel gas ejection port 48</b>C, and the ejected oxidant gas is guided along the side wall portion 48</b>A of the fuel gas ejection portion 48 . Since the oxidant gas is guided along the side wall portion 48A of the fuel gas ejection portion 48 in this way, the oxidant gas can be prevented from being directly blown onto the flame of the fuel gas ejection portion 48, and stable combustion can be achieved. is realized.

Further, according to the present embodiment, since the oxidant gas guide portion 46 guides the oxidant gas toward the side wall portion 48A forming the fuel gas ejection portion 48, the oxidant gas guided by the oxidant gas guide portion 46 is oxidized. After the agent gas collides with the fuel gas ejection portion 48 , it flows along the side wall portion 48 A of the fuel gas ejection portion 48 . This makes it possible to guide the oxidant gas along the side wall portion 48A of the fuel gas ejection portion 48 .

Further, according to this embodiment, the opening area of the oxidizing gas ejection port 47A is larger than the opening area of the fuel gas ejection port 48C. As a result, the oxidant gas is sufficiently supplied, and stable combustion is realized.

Further, according to the present embodiment, since the oxidant gas ejected from the oxidant gas ejection port 47A is the residual oxidant gas that has not been used in the power generation reaction in the fuel cell stack 2, it is newly oxidized from the outside. This eliminates the need to provide a structure (such as piping) for supplying the agent gas.

In addition, in the present embodiment, the residual fuel gas supplied to the fuel gas ejection part 48 is not premixed with the residual fuel gas that has not been used in the power generation reaction in the fuel cell stack 2, and thus the residual fuel gas is not premixed with the oxidant gas. Since the fuel gas is ejected from the fuel gas ejection port 48C in a state where the concentration of the fuel gas is high, more stable combustion is realized.

In addition, in the present embodiment, the fuel gas ejection portion 48 is provided with a plurality of fuel gas ejection ports 48C arranged in a line. The heat generated in 12 can be used more efficiently for heating the reformer 10 and the like.

Further, according to the fuel cell module 1 of the present embodiment, stable combustion in the combustor 12 is realized, so that the raw fuel gas can be reformed reliably in the reformer 10 .

Further, in this embodiment, the fuel cell stack 2 is arranged outside the housing 6 independently of the housing 6, so that the thermal influence of the combustor 12 on the fuel cell stack 2 can be reduced.

<Second embodiment>
A fuel cell module according to a second embodiment of the present invention will be described below. The configuration of the fuel cell module according to the second embodiment differs from that of the first embodiment only in the configuration of the combustor. In addition, about the structure similar to 1st Embodiment, the same code|symbol is attached|subjected and detailed description is abbreviate|omitted.

FIG. 6 is a vertical sectional view of a reformer/heater for a fuel cell module according to a second embodiment of the present invention. 7 and 8 show the combustor of the fuel cell module shown in FIG. 6, FIG. 7 being a perspective view, and FIG. 8 being an exploded perspective view. 6 to 8, the air flow path 6A (outer wall) of the housing 6 is omitted, and only the bottom portion of the housing is shown in FIGS.

As shown in FIGS. 6 to 8, the combustor 112 consists of a manifold for ejecting residual fuel gas and residual oxidant gas. 142 and a second combustor-forming member 144 . The bottom surface 6a of the housing 6 is formed with an oxidizing gas opening 6B to which the oxidizing gas discharge passage 36 is connected, and a fuel opening 6C to which the fuel discharge passage 34 is connected.

The first combustor forming member 142 includes a rectangular flat plate portion 142A, a tubular portion 142B erected downward from the flat plate portion 142A, and a fuel gas ejection portion 148 provided to cover the flat plate portion 142A. and a pedestal portion 143 provided on the lower surface of both ends in the longitudinal direction of the flat plate portion 142A. The tubular portion 142B is connected to an opening formed in the center of the flat plate portion 142A. Note that the tubular portion 142B of the first combustor forming member 142 constitutes the fuel discharge passage 34 . The fuel gas ejection portion 148 includes a side wall portion 148A standing along the periphery of the flat plate portion 142A, and a top surface portion 148B provided to cover the upper surface of the side wall portion 148A. The side wall portion 148A stands vertically with respect to the flat plate portion 142A. The corners of the side wall portion 148A and the top surface portion 148B on both sides in the width direction are chamfered. The top surface portion 148B has circular openings arranged in a line in the center in the width direction. A cylindrical side wall portion 148D is formed around the periphery of each opening, and a fuel gas ejection port 148C is formed at the upper end of the cylindrical side wall portion 148D. These fuel gas ejection ports 148C are provided at regular intervals in the longitudinal direction. Note that the side wall portion 148A and the cylindrical side wall portion 148D of the fuel gas ejection portion 148 are vertical in this embodiment.

The second combustor forming member 144 has a flat annular edge 149 and an oxidizing gas guide 146 projecting upward from the edge 149 .
The edge portion 149 is flat and has an outer shape substantially equal to the bottom surface 6 a of the housing 6 .

The oxidant gas guide portion 146 has a side wall portion 146A that is rectangular in plan view and stands upward inside the edge portion, and a flat plate portion 146B that closes the upper side of the side wall portion 146A. The corners of the side wall portions 146A and the flat plate portion 146B on both sides in the width direction are chamfered. In addition, a plurality of oxidizing gas ejection openings 147 are formed in the widthwise center of the flat plate portion 146B. The oxidizing gas ejection openings 147 are arranged in a line at equal intervals in the longitudinal direction at the center in the width direction of the flat plate portion 146B. Each oxidizing gas ejection opening 147 has an elongated shape extending in the width direction, and the width and length of the oxidizing gas ejection opening 147 are larger than the diameter of the fuel gas ejection port 148C. Also, the oxidizing gas ejection opening 147 is formed at a position corresponding to the fuel gas ejection port 148C.

The second combustor forming member 144 is arranged such that the edge 149 contacts the bottom surface 6a of the housing 6, and the edge 149 and the bottom surface 6a of the housing 6 are welded. The base portion 143 of the first combustor forming member 142 is grounded to the bottom surface 6 a of the housing 6 . The first combustor forming member 142 is arranged such that the tubular portion 142B passes through the fuel opening 6C in the bottom surface 6a of the housing 6. As shown in FIG. With this arrangement, each fuel gas ejection port 148</b>C is positioned at the center of the corresponding oxidizing gas ejection opening 147 . The height of the upper end of the cylindrical side wall portion 148D of the fuel gas ejection port 148C is equal to the height of the flat plate portion 146B of the second combustor forming member 144. As shown in FIG. A gap between the oxidant gas ejection opening 147 and the cylindrical side wall portion 148D of the fuel gas ejection port 148C functions as an oxidant gas ejection port 147A through which the oxidant gas is ejected. A gap is formed between the top surface portion 148B of the fuel gas ejection portion 148 and the flat plate portion 146B of the second combustor forming member 144 .

With such a configuration, an oxidant gas supply space 150 is formed as an internal space between the bottom surface 6 a of the housing 6 and the oxidant gas guide portion 146 of the second combustor forming member 144 . The oxidizing gas supply space 150 communicates with the oxidizing gas discharge passage 36 through the oxidizing gas opening 6B in the bottom surface 6a. Also, the oxidizing gas supply space 150 communicates with the internal space of the housing 6 through the oxidizing gas ejection port 147A. The opening area (total opening area) of the oxidizing gas ejection port 147A is larger than the opening area (total opening area) of the fuel gas ejection port 148C. In the present embodiment, residual oxidant gas that has not been used for power generation in the fuel cell stack 2 is supplied to the oxidant gas supply space 150 via the oxidant gas discharge passage 36, but this is not the only option. It is also possible to supply the oxidant gas directly from the outside without needing to do so.

A fuel gas supply space 152 is formed between the flat plate portion 142A of the first combustor forming member 142 and the fuel gas ejection portion 148 . The fuel gas supply space 152 communicates with the fuel discharge passage 34 . Further, the fuel gas supply space 152 communicates with the internal space of the housing 6 through the fuel gas ejection port 148C. A cylindrical side wall portion 148D of a fuel gas ejection port 148C of the fuel gas ejection portion 148 extends upward, and the upper end fuel gas ejection port 148C is positioned at the same height as the oxygen-containing gas ejection port 147A. As a whole, the first combustor forming member 142 and the second combustor forming member 144 have a symmetrical configuration with the center in the width direction as a plane of symmetry. The fuel gas ejection ports 148C are arranged in a row along the plane of symmetry.

FIG. 9 is a vertical sectional view showing the flow of residual fuel gas and residual oxidant gas in the combustor of the fuel cell module according to the second embodiment of the invention. Residual fuel gas that has not been used for power generation in the fuel cell stack 2 is supplied to the fuel gas supply space 152 through the fuel discharge passage 34 . As shown in FIG. 9, the residual fuel gas supplied to the fuel gas supply space 152 is jetted vertically upward into the internal space of the housing 6 from the fuel gas jetting port 148C at the upper end of the fuel gas jetting portion 148. As shown in FIG.

On the other hand, residual oxidant gas that has not been used for power generation in the fuel cell stack 2 is supplied to the oxidant gas supply space 150 through the oxidant gas discharge passage 36 . The residual oxidant gas supplied to the oxidant gas supply space 150 through the oxidant gas discharge passage 36 collides with the flat plate portion 142A of the first combustor forming member 142 and flows outward in the horizontal direction. Then, the oxidant gas is guided toward the oxidant gas ejection port 47A by the side wall portion 146A and the flat plate portion 146B of the oxidant gas guide portion 146. As shown in FIG. The residual oxidant gas guided by the oxidant gas guide portion 146 collides with the cylindrical side wall portion 148D of the fuel gas ejection portion 148 . The remaining oxygen-containing gas is then guided upward along the cylindrical side wall portion 148D of the fuel gas ejection portion 148 and ejected into the internal space of the housing 6 from the oxygen-containing gas ejection port 147A. The flow velocity of the residual oxidant gas flowing along the cylindrical side wall portion 148D of the fuel gas ejection portion 148 can be adjusted by a method such as changing the opening area of the oxidant gas ejection port 47A.

The residual fuel gas ejected in this manner is ignited by an ignition device (not shown) and combusted together with the residual oxidant gas. Combustion heat generated by burning the residual fuel gas heats the reformer 10 and also heats the air flowing through the air flow path 6A of the housing 6 .

As described above, according to the second embodiment, the following effects are achieved.
According to this embodiment, the residual oxidizing gas is jetted from the same height as the fuel gas jetting port 148C, and the residual oxidizing gas is guided along the side wall portion 48A of the fuel gas jetting portion 148. FIG. Since the oxidant gas is guided along the cylindrical side wall portion 148D of the fuel gas ejection portion 148 in this way, the oxidant gas can be prevented from being directly blown onto the flame of the fuel gas ejection portion 148, and stable combustion can be achieved. Combustion is achieved.

Further, according to the present embodiment, since the oxidant gas guide portion 146 guides the oxidant gas toward the cylindrical side wall portion 48D of the fuel gas ejection portion 148, the oxidant gas guided by the oxidant gas guide portion 146 After colliding with the fuel gas ejection portion 148 , the gas flows along the cylindrical side wall portion 148</b>D of the fuel gas ejection portion 148 . This makes it possible to guide the oxidant gas along the cylindrical side wall portion 148</b>D of the fuel gas ejection portion 148 .

Further, according to this embodiment, the opening area of the oxidizing gas ejection port 147A is larger than the opening area of the fuel gas ejection port 148C. As a result, the oxidant gas is sufficiently supplied, and stable combustion is realized.

Further, according to the present embodiment, since the oxidant gas ejected from the oxidant gas ejection port 147A is the residual oxidant gas that has not been used in the power generation reaction in the fuel cell stack 2, it is newly oxidized from the outside. This eliminates the need to provide a structure (such as piping) for supplying the agent gas.

In addition, in the present embodiment, the residual fuel gas supplied to the fuel gas ejection part 148 is not premixed with the residual fuel gas that has not been used in the power generation reaction in the fuel cell stack 2, and therefore the residual fuel gas is not premixed with the oxidant gas. Since the fuel gas is ejected from the fuel gas ejection port 148C in a state where the concentration of the fuel gas is high, more stable combustion is realized.

In addition, in the present embodiment, the fuel gas ejection portion 148 is provided with a plurality of fuel gas ejection ports 148C arranged in a line. The heat generated in 112 can be used more efficiently for heating the reformer 10 and the like.

Further, according to the fuel cell module 1 of the present embodiment, stable combustion in the combustor 112 is realized, so that the raw fuel gas can be reformed reliably in the reformer 10 .

Further, in this embodiment, the fuel cell stack 2 is arranged outside the housing 6 independently of the housing 6, so that the thermal influence of the combustor 112 on the fuel cell stack 2 can be reduced.

1 Fuel cell module 2 Fuel cell stack 4 Fluid supply device 4a Evaporator 4b Reformer/heater 6 Housing 6A Air flow path 6B Oxidant gas opening 6C Fuel opening 6a Bottom surface 8 Heat insulating material 10 Reformer 12 Combustor 20 Water Supply pipe 22 Raw fuel gas supply pipe 23 Exhaust gas discharge pipe 24 Air supply pipe 26 Exhaust gas pipe 28 Mixed gas pipe 30 Fuel supply passage 32 Oxidant gas supply passage 34 Fuel discharge passage 36 Oxidant gas discharge passage 42 First Combustor forming member 42A Flat plate portion 42B Tubular portion 44 Second combustor forming member 46 Oxidant gas guide portion 46A Side wall portion 46B Flat plate portion 47 Oxidant gas ejection portion 47A Oxidant gas ejection port 48 Fuel gas ejection portion 48A Side wall portion 48B top surface portion 48C fuel gas ejection port 48D cylindrical side wall portion 49 edge portion 50 oxidant gas supply space 52 fuel gas supply space 112 combustor 142 first combustor forming member 142A flat plate portion 142B tubular portion 143 pedestal portion 144 second Combustor forming member 146 Oxidant gas guide portion 146A Side wall portion 146B Flat plate portion 147 Oxidant gas ejection opening 147A Oxidant gas ejection port 148 Fuel gas ejection portion 148A Side wall portion 148B Top surface portion 148C Fuel gas ejection port 148D Cylindrical side wall portion 149 Rim Part 150 Oxidant gas supply space 152 Fuel gas supply space

Claims (7)

A combustor for supplying a residual fuel gas and an oxidant gas that have not been used in a power generation reaction in a fuel cell and combusting the residual fuel gas together with the oxidant gas,
a fuel gas ejection part having a side wall extending upward and ejecting the residual fuel gas from a fuel gas ejection port at the upper end ;
The oxidant gas is ejected below the fuel gas ejection port,
the oxidant gas is guided in a direction along the side wall of the fuel gas ejection portion ;
further comprising an oxidizing gas guide portion for supplying an oxidizing gas to the internal space and guiding the supplied oxidizing gas;
The oxidizing gas guide section guides the oxidizing gas toward the sidewall forming the fuel gas ejection section.
A combustor characterized by: The opening area of the oxidizing gas ejection port through which the oxidizing gas is ejected from the internal space is larger than the opening area of the fuel gas ejection port.
The combustor of claim 1 . The ejected oxidant gas is residual oxidant gas that has not been used in the power generation reaction in the fuel cell.
A combustor according to claim 1 or 2 . The residual fuel gas supplied to the fuel gas ejection part is not premixed with the residual fuel gas that has not been used in the power generation reaction in the fuel cell, and the oxidant gas is not premixed.
The combustor according to any one of claims 1-3 . The fuel gas ejection part is provided with a plurality of fuel gas ejection ports arranged in a row,
The combustor according to any one of claims 1-4 . a fuel cell;
The combustor according to any one of claims 1 to 5 , wherein residual fuel gas that has not been used in the power generation reaction in the fuel cell is combusted together with the oxidant gas;
a reformer disposed above the combustor for reforming the raw fuel gas by combustion heat of the combustor to generate fuel gas to be supplied to the fuel cell;
fuel cell module. further comprising a housing containing the combustor and the reformer;
The fuel cell is arranged outside the housing independently of the housing,
The fuel cell module according to claim 6 .

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