JP7094168B2 - Combustor and fuel cell module - Google Patents

Description

The present invention relates to a combustor and a fuel cell module including the combustor.

Conventionally, a solid oxide fuel cell stack, a reforming unit that reforms raw fuel gas to generate reformed gas supplied to the fuel cell stack, and a stack exhaust gas discharged from the fuel cell stack are burned. Fuel cell modules with a combustor are known.

Japanese Unexamined Patent Publication No. 2016-24871

In the combustor of this fuel cell module, an oxidant gas (air) is used to burn the stack exhaust gas discharged from the fuel cell stack. Combustibility is affected by how the stack exhaust gas and oxidant gas are supplied to the combustion chamber. Depending on the method of supply to the combustion chamber, it is conceivable that the combustion of the stack exhaust gas becomes insufficient, the stack exhaust gas is discharged from the combustor without being burned, or the flame disappears in the combustor.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a combustor for improving the combustibility of fuel gas in a combustor, and a fuel cell module provided with the combustor. be.

In order to achieve the above object, the combustor according to claim 1 of the present invention is a combustion chamber formed inside a tubular combustion chamber peripheral wall in which a mixed gas in which a fuel gas and an oxidant gas are mixed is burned. And, the oxidant gas is supplied from the outside adjacent to one end side of the cylinder shaft of the combustion chamber, and the oxidant gas chamber separated from the combustion chamber by the oxidant gas chamber partition wall, and the oxidant gas chamber. The fuel gas is supplied from the outside and penetrates the fuel gas chamber partitioned from the oxidant gas chamber by the fuel gas chamber partition wall and the oxidant gas chamber partition wall, and the combustion chamber is arranged inside in the radial direction. The oxidant gas nozzle that communicates the oxidant gas chamber with the oxidant gas chamber, the overlapping portion that penetrates the fuel gas chamber partition wall and overlaps with the oxidant gas nozzle in the penetration direction, and the ejection destination of the fuel gas is the oxidant. It is a surface of the gas chamber partition wall on the oxidant gas chamber side and has a non-overlapping portion that does not overlap with the oxidant gas nozzle, and includes a fuel gas nozzle for discharging the fuel gas to the oxidant gas chamber. ..

In this combustor, the fuel gas supplied to the fuel gas chamber on the inner side in the radial direction is ejected from the fuel gas nozzle to the oxidant gas chamber. Further, the oxidant gas supplied to the oxidant gas chamber is ejected from the oxidant gas nozzle to the combustion chamber together with the fuel gas from the fuel gas nozzle. Since the fuel gas nozzle has a non-overlapping portion that does not overlap with the oxidant gas nozzle, a part of the fuel gas that has passed through the fuel gas nozzle hits the oxidant gas partition wall and causes turbulence. This promotes the mixing of the fuel gas and the oxidant gas, and can improve the combustibility of the mixed gas ejected from the oxidant gas nozzle into the combustion chamber in the combustor.

In the combustor according to claim 2, the fuel gas nozzle and the oxidant gas nozzle are non-coaxial.

By arranging the fuel gas nozzle and the oxidant gas nozzle non-coaxially in this way, it is possible to easily form overlapping portions and non-overlapping portions in the fuel gas nozzle regardless of the magnitude relationship between the fuel gas nozzle and the oxidant gas nozzle. can.

In the combustor according to claim 3, the oxidant gas chamber partition wall has a tubular tubular wall portion arranged coaxially with the combustion chamber peripheral wall and the combustion chamber peripheral wall from the lower outer periphery of the tubular wall portion. It has a tapered wall portion whose diameter is expanded to and the combustion chamber is tapered so as to be convex toward one end side.
The oxidant gas nozzle is formed in the tubular wall portion, and the tapered wall portion has a plurality of tapered wall communication holes that penetrate the tapered wall portion and communicate the oxidant gas chamber and the combustion chamber. It is formed.

In the combustor according to claim 3, the mixed gas of the fuel gas and the oxidant gas ejected from the oxidant gas nozzle formed on the tubular wall portion is sent from the radial inside to the radial outside along the tapered wall portion. It can be diffused to and the length of the flame in the combustor can be shortened.

The combustor according to claim 4 includes a tubular inner tubular wall in which the fuel gas chamber partition wall is arranged inside the tubular wall portion, and a top wall covering the tip of the inner tubular wall. It is formed and the fuel gas nozzle is formed on the inner cylinder wall.

In the combustor according to claim 4, the fuel gas chamber is formed by the space inside the cylinder by forming the fuel gas chamber partition wall including the tubular inner cylinder wall and the top wall covering the tip of the inner cylinder wall. be able to.

In the combustor according to claim 5, the tapered wall communication hole is a concentric annular zone having the same width in the radial direction of the combustion chamber. It is formed so that the permeation flow rate of the communication hole is large.

In the combustor according to claim 5, the permeation flow rate of the tapered wall communication hole of the oxidant gas is larger on the radial outer side than on the radial inner side of the combustion chamber. Therefore, of the oxidant gas supplied to the oxidant gas, the flow rate supplied to the radial outside of the combustion chamber increases, and the flow rate mixed with the fuel gas decreases, so that the combustion speed of the combustion gas can be reduced. .. As a result, the concentration of flames near the cylinder shaft of the combustor is suppressed, and burning and deterioration due to local heating can be suppressed. Further, when the air ratio supplied to the combustor is high, the air can be exhausted without contributing to combustion, so that the combustibility can be improved.

In the combustor according to claim 6, the tapered wall communication holes are formed in a plurality of concentric rows, and the tapered wall communication holes in the radial outer row are larger than the number of the tapered wall communication holes in the radial inner row. It is characterized by a large number of.

In this way, by increasing the number of tapered wall communication holes in the radial outer row rather than the number of tapered wall communication holes in the radial inner row, the oxidation of the radial outer side of the combustion chamber is larger than the radial inner side. The permeation flow rate of the agent gas can be increased. Therefore, the combustion speed of the combustion gas can be reduced, and the combustibility can be improved even when the air ratio supplied to the combustor is high.

In the combustor according to claim 7, the tapered wall communication holes are concentrically formed in a plurality of rows, and the tapered wall communication in a row outward in the radial direction from the opening size of the tapered wall communication hole in the radial inner row. It is characterized by a large opening size of the hole.

In this way, by making the opening size of the tapered wall communication hole in the radial outer row larger than the opening size of the tapered wall communication hole in the radial inner row, the radial outer side of the combustion chamber is larger than the radial inner side. The permeation flow rate of the oxidant gas can be increased. Therefore, the combustion speed of the combustion gas can be reduced, and the combustibility can be improved even when the air ratio supplied to the combustor is high.

The fuel cell module according to claim 8 includes a fuel cell stack that generates power by an electrochemical reaction between fuel gas and an oxidant gas, a vaporization unit in which raw fuel is vaporized to generate raw fuel gas, and the raw material fuel. The reforming section where the fuel gas is generated from the gas, the fuel gas which is the fuel electrode exhaust gas discharged from the fuel electrode of the fuel cell stack, and the air electrode exhaust gas discharged from the air electrode of the fuel cell stack. The combustor according to any one of claims 1 to 8, which burns a stack exhaust gas mixed with an oxidizing agent gas.

According to the fuel cell module according to claim 8, since the above-mentioned combustor is applied, even if the properties and composition of the stack exhaust gas, which is a mixed gas of the fuel gas and the oxidant gas, are different at the time of startup or power generation. , Stacked exhaust gas can be stably burned with a single combustor. As a result, the structure of the combustor and its surroundings can be simplified, so that the fuel cell module can be miniaturized and the cost can be reduced.

In the fuel cell module according to claim 8, the combustor is provided above the fuel cell stack, and the reforming portion is provided above the combustor coaxially with the combustor and mutually. A heat insulating space, a combustion exhaust gas discharged from the combustor, which is composed of at least a triple tubular wall having a gap between the two, and between the inside and the tubular wall of the triple tubular wall. Each has a flow path and a reforming flow path in which the raw material fuel gas is reformed by utilizing the heat of the combustion exhaust gas to generate the fuel gas, and the vaporization section is above the reforming section. It is composed of at least triple cylindrical or elliptical tubular walls that are provided coaxially with the reforming portion and have gaps between them, and are inside and tubular in the triple tubular wall. Between the walls, there is a heat insulating space, a combustion exhaust gas flow path through which the combustion exhaust gas flows, and a vaporization flow path in which the raw material fuel is vaporized by heat exchange with the combustion exhaust gas to generate the raw material fuel gas.

According to the fuel cell module according to claim 9, since the vaporizing part and the reforming part are each formed by at least a triple tubular wall, the structures of the vaporizing part and the reforming part can be simplified. , The vaporization part and the reforming part can be miniaturized. Further, since the combustor, the reforming unit, and the vaporizing unit are arranged coaxially, the fuel cell module can be miniaturized in the radial direction.

As described above, according to the present invention, the combustibility of the fuel gas can be improved in the combustor.

It is a vertical sectional view of a fuel cell module. It is an enlarged view of the main part of a fuel cell module. It is an enlarged view of the main part of a fuel cell module. It is an enlarged view of the main part of a fuel cell module. It is a perspective view which includes the vertical cross section of the combustor which concerns on 1st Embodiment. It is a top view (A) and the vertical sectional view (B) which partially enlarged the combustor which concerns on 1st Embodiment. It is an enlarged sectional view around the oxidant gas nozzle and the fuel gas nozzle which concerns on 1st Embodiment. It is an enlarged sectional view around the oxidant gas nozzle and the fuel gas nozzle which concerns on the modification of 1st Embodiment. It is a graph which shows the relationship between the combustion air ratio and the carbon monoxide concentration of the combustion exhaust gas of the combustor which concerns on 1st Embodiment and the combustor which concerns on a comparative example. It is the top view (A) and the vertical sectional view (B) which partially enlarged the combustor which concerns on 2nd Embodiment. It is the top view (A) and the vertical sectional view (B) which partially enlarged the combustor which concerns on the modification of 2nd Embodiment.

[First Embodiment]
Hereinafter, the first embodiment of the present invention will be described. In the figure, the horizontal direction is indicated by an arrow X, and the vertical direction is indicated by an arrow Z.

<Fuel cell module>
As shown in FIG. 1, the fuel cell module M according to the first embodiment includes a fuel cell stack 10, a container 20, a heat insulating layer 130, and a heat insulating material 140.

<Fuel cell cell stack>
As an example, a solid oxide fuel cell (SOFC) is applied to the fuel cell stack 10. The fuel cell stack 10 has a plurality of flat plate-shaped cells 12 stacked in the vertical direction, and a manifold 14. The shape of the cell 12 may be any shape such as a cylindrical shape or a cylindrical flat plate shape, in addition to the flat plate shape. Each cell 12 has a fuel electrode, an electrolyte layer, and an air electrode.

Fuel gas (reforming gas) is supplied to the fuel electrode of each cell 12, and oxidant gas is supplied to the air electrode of each cell 12. Each cell 12 generates electricity by an electrochemical reaction between the fuel gas and the oxidant gas, and generates electricity as the cell 12 generates electricity.

<Container>
The container 20 is composed of a plurality of (nine) pipe materials 21 to 29. Each of the plurality of pipe materials 21 to 29 is formed in a cylindrical shape having a perfect circular cross section, and is made of a metal having high heat transfer. The plurality of pipe materials 21 to 29 are arranged in order from the inside to the outside of the container 20. In the present embodiment, the container 20 is composed of nine pipe materials 21 to 29 as an example, but the container may be composed of another number (8 or less, 10 or more) of pipe materials.

The first pipe material 21 from the inside of the container 20 is provided from above the fuel cell stack 10 to the upper end of the container 20. The second pipe material 22 and the third pipe material 23 are formed with a length corresponding to the upper part of the first pipe material 21, and the second pipe material 22 is the upper part of the pipe material 21 from the outside of the first pipe material 21. It is joined to. The fourth pipe material 24 is provided in the central portion in the height direction of the container 20, and the fifth pipe material 25 and the sixth pipe material 26 are provided from the lower end portion to the upper end portion of the container 20. .. The seventh pipe material 27, the eighth pipe material 28, and the ninth pipe material 29 are provided from the central portion to the upper end portion in the height direction of the container 20.

The sixth pipe material 26 and the seventh pipe material 27 are connected via a horizontally extending connecting portion 31, and the fifth pipe material 25 and the eighth pipe material 28 are connected via a horizontally extending connecting portion 32. Are connected. Further, the upper end portion of the ninth pipe material 29 is fixed to the upper end portion of the third pipe material 23 via the connecting portion 33 extending in the horizontal direction.

The lower end of the fifth pipe 25 is fixed to the bottom wall 34, and the lower end of the sixth pipe 26 is fixed to the bottom wall 35. A fuel cell stack 10 is placed on the bottom wall portion 34, and the bottom wall portion 34 and the bottom wall portion 35 are fixed by a spacer 36.

The container 20 composed of the plurality of pipe materials 21 to 29 has a vaporization unit 40, a reforming unit 60, a combustion unit 90, a preheating unit 100, and a heat exchange unit 110, according to function.

<Vaporization part>
As shown in FIGS. 2 and 3, the vaporization unit 40 is composed of quadruple cylindrical walls 41 to 44. The innermost cylindrical wall 41 among the quadruple tubular walls 41 to 44 is composed of the upper part of the first pipe material 21 and the second pipe material 22, and the quadruple tubular walls 41 to 44. The second tubular wall 42 from the inside is composed of the third pipe material 23. Further, the third tubular wall 43 from the inside among the quadruple tubular walls 41 to 44 is composed of the upper part of the fifth pipe material 25, and the outermost cylinder among the quadruple tubular walls 41 to 44. The shaped wall 44 is composed of the upper part of the sixth pipe member 26.
In the present embodiment, as an example, the vaporization unit 40 is composed of the quadruple tubular walls 41 to 44, but the vaporization unit is composed of another number (3 or less, 5 or more) of tubular walls. You may.

The vaporization section 40 composed of the quadruple tubular walls 41 to 44 is provided coaxially with the reforming section 60 above the reforming section 60, which will be described later. The quadruple tubular walls 41 to 44 constituting the vaporization portion 40 have a gap between them, and the heat insulating space 45 is located from the inside to the outside of the quadruple tubular walls 41 to 44. The vaporization flow path 46, the combustion exhaust gas flow path 47, and the oxidant gas flow path 48 are formed in this order.

That is, the space inside the first tubular wall 41 is formed as a heat insulating space 45, and the gap between the first tubular wall 41 and the second tubular wall 42 is used as a vaporization flow path 46. It is formed. Further, the gap between the second tubular wall 42 and the third tubular wall 43 is formed as a combustion exhaust gas flow path 47, and the third tubular wall 43 and the fourth tubular wall 44 are formed. The gap between the two is formed as an oxidizing agent gas flow path 48. In FIGS. 2 and 3, the heat insulating space 45 is hollow, but the heat insulating space 45 may be filled with the heat insulating material 49.

A raw fuel supply pipe 50 extending radially outward of the container 20 is connected to the upper end of the vaporization flow path 46. The raw fuel supply pipe 50 is located above the connecting portions 31 to 33. The vaporization flow path 46 is formed with the upper side in the vertical direction as the upstream side, and the raw material fuel 161 supplied from the raw material fuel supply pipe 50 flows from the upper side to the lower side in the vertical direction in the vaporization flow path 46. As the raw material 161 supplied from the raw material fuel supply pipe 50, a hydrocarbon fuel mixed with reforming water is used. Further, as the hydrocarbon fuel contained in the raw material fuel 161, for example, city gas is preferably used, but a gas containing a hydrocarbon as a main component such as propane may be used, and a hydrocarbon-based liquid may be used. May be used.

The vaporization flow path 46 is provided with a spiral member 51 formed spirally around the axis of the vaporization section 40, and the spiral member 51 causes the vaporization flow path 46 to rotate around the axis of the vaporization section 40. It is formed in a spiral shape.

The lower end of the combustion exhaust gas flow path 47 communicates with the combustion chamber 207 (see FIG. 4) formed in the combustor 200 via the combustion exhaust gas flow path 67 formed in the reforming portion 60 described later. The combustion exhaust gas flow path 47 is formed with the lower side in the vertical direction as the upstream side, and is discharged from the combustor 200 and supplied to the combustion exhaust gas flow path 47 through the combustion exhaust gas flow path 67 of the reforming unit 60. The combustion exhaust gas 168 flows from the lower side in the vertical direction to the upper side.

At the upper end of the combustion exhaust gas flow path 47, a straightening vane 52 formed in an annular shape along the circumferential direction of the combustion exhaust gas flow path 47 is provided. A plurality of orifices 53 are formed on the straightening vane 52 at intervals in the circumferential direction. The plurality of orifices 53 penetrate in the plate thickness direction of the straightening vane 52. The straightening vane 52 may be omitted.

The upper end of the oxidant gas flow path 48 communicates with the oxidant gas flow path 118 formed in the heat exchange section 110 described later. The oxidant gas flow path 48 is formed with the upper side in the vertical direction as the upstream side, and the oxidant gas 164 supplied from the oxidant gas flow path 118 of the heat exchange unit 110 to the oxidant gas flow path 48. Flows from the upper side to the lower side in the vertical direction.

<Modified part>
As shown in FIG. 3, the reforming section 60 is composed of quadruple cylindrical walls 61 to 64. The tubular wall 61 located on the innermost side of the quadruple tubular walls 61 to 64 is composed of the lower part of the first pipe material 21, and is the second cylinder from the inside of the quadruple tubular walls 61 to 64. The shaped wall 62 is composed of a fourth pipe member 24. Further, the third tubular wall 63 from the inside among the quadruple tubular walls 61 to 64 is formed by the central portion in the height direction of the fifth tubular wall 25, and the quadruple tubular walls 61 to 64. The outermost cylindrical wall 64 is formed by the central portion in the height direction of the sixth pipe member 26.

The reforming portion 60 composed of the quadruple tubular walls 61 to 64 is provided coaxially with the combustor 200 above the combustor 200 (see FIG. 4) described later. The quadruple cylindrical walls 61 to 64 constituting the reforming portion 60 have a gap between them. A heat insulating space 65, a combustion exhaust gas flow path 67, a reforming flow path 66, and an oxidant gas flow path 68 are formed in this order from the inside to the outside of the quadruple tubular walls 61 to 64.
In the present embodiment, as an example, the reforming portion 60 is composed of the quadruple tubular walls 61 to 64, but the reforming portion is formed by another number (3 or less, 5 or more) of tubular walls. May be configured.

That is, the space inside the first tubular wall 61 is formed as a heat insulating space 65, and the gap between the first tubular wall 61 and the second tubular wall 62 is the combustion exhaust gas flow path 67. Is formed as. Further, the gap between the second tubular wall 62 and the third tubular wall 63 is formed as a reforming flow path 66, and the third tubular wall 63 and the fourth tubular wall 64 are formed. The gap between the two is formed as an oxidant gas flow path 68.

The heat insulating space 65 communicates with the heat insulating space 45 of the vaporization unit 40 described above. In FIG. 3, the heat insulating space 65 is hollow, but the heat insulating space 65 may be filled with the heat insulating material 69. The lower end of the combustion exhaust gas flow path 67 communicates with the combustion chamber 207 (see FIGS. 4 and 5) formed in the combustor 200 described later. The combustion exhaust gas flow path 67 is formed with the lower side in the vertical direction as the upstream side, and the combustion exhaust gas 168 discharged from the combustor 200, which will be described later, flows in the combustion exhaust gas flow path 67 from the lower side in the vertical direction to the upper side. ..

<Mixing part and dispersion part>
At the upper end of the reforming portion 60, a mixing portion 80 extending upward in the vertical direction is formed. The mixing unit 80 is located between the vaporization unit 40 and the reforming unit 60, that is, more specifically, above the reforming unit 60 and radially outside the lower end portion of the vaporization unit 40. A connecting pipe 81 extends radially outward from a part of the lower end portion of the vaporization portion 40 in the circumferential direction. The connecting pipe 81 constitutes a connecting portion with the vaporizing portion 40 in the mixing portion 80, and the inside of the connecting pipe 81 is formed as an orifice 82 penetrating in the horizontal direction. The connecting pipe 81 (orifice 82) is located on the radial outer side of the vaporization flow path 46 and communicates with the lower end portion of the vaporization flow path 46. The mixing unit 80 has only one connecting pipe 81 (orifice 82). The mixing portion 80 is provided with a facing wall portion 86 located on the reforming flow path 66 side (outward in the radial direction) with respect to the orifice 82 and facing the orifice 82.

The inlet (upper end) of the reforming flow path 66 is communicated with the vaporization flow path 46 via the mixing portion 80 and the connecting pipe 81. The reforming flow path 66 is formed with the upper side in the vertical direction as the upstream side, and the raw fuel gas 162 supplied from the vaporization flow path 46 flows from the upper side in the vertical direction to the lower side in the reforming flow path 66.

At the inlet of the reforming flow path 66, a partition plate 83 formed in an annular shape along the circumferential direction of the reforming flow path 66 is provided. A plurality of orifices 84 are formed on the partition plate 83 at regular intervals in the circumferential direction. The plurality of orifices 84 penetrate in the plate thickness direction (vertical direction) of the partition plate 83, and raw fuel gas 162 flows into the reforming flow path 66 through the plurality of orifices 84. A plurality of partition plates 83 may be provided at intervals in the vertical direction.

The reforming flow path 66 is provided with a reforming catalyst layer 70 for generating fuel gas 163 from the raw fuel gas 162 over the entire length in the circumferential direction and the axial direction of the reforming flow path 66. For the reforming catalyst layer 70, for example, a granular catalyst or a honeycomb catalyst carrying a metal such as nickel, ruthenium, platinum, or rhodium as an active metal is used.

The upper end of the oxidant gas flow path 68 communicates with the oxidant gas flow path 48 formed in the vaporization portion 40 described above. The oxidant gas flow path 68 is formed with the upper side in the vertical direction as the upstream side, and the oxidant gas 164 supplied from the oxidant gas flow path 48 of the vaporization unit 40 is formed in the oxidant gas flow path 68. It flows from the upper side in the vertical direction to the lower side.

<Combustion part>
As shown in FIG. 4, the combustion unit 90 is provided coaxially with the reforming unit 60 below the reforming unit 60 described above. The combustor 200 shown in FIG. 5 is formed inside the combustion unit 90. The combustor 200 includes a combustion chamber peripheral wall 201, a combustion chamber wall 202, a rectifying section 203, an inner tubular wall 204 as a fuel gas chamber partition wall, a tubular wall portion 232 as an oxidizing agent gas chamber partition wall, and a taper. It has a wall portion 205.

The combustion chamber peripheral wall 201 is formed by extending the second cylindrical wall 62 from the inside downward among the quadruple cylindrical walls 61 to 64 constituting the reforming portion 60 (see FIG. 4). ). In the combustor 200 shown in FIG. 5, the stepped portion 201A is formed on the peripheral wall 201 of the combustion chamber, but the fuel cell module M in FIG. 1 is shown in a state where the stepped portion 201A is omitted. The combustion chamber peripheral wall 201 is formed in a cylindrical shape, and a combustion chamber 207 is formed inside the combustion chamber peripheral wall 201. The combustion chamber 207 is formed with the vertical direction as the axial direction. In the combustion chamber 207, a mixed gas in which a fuel gas described later and an oxidant gas are mixed is burned.

The combustion chamber peripheral wall 202 has a smaller diameter than the combustion chamber peripheral wall 201, and is provided inside the combustion chamber peripheral wall 201. The combustion chamber wall 202 is formed by the lower end portion of the innermost cylindrical wall 61 among the quadruple cylindrical walls 61 to 64 constituting the reforming portion 60 (see FIG. 4). As shown in FIG. 5, the combustion chamber wall 202 is arranged above the combustion chamber 207. The gap between the combustion chamber peripheral wall 201 and the combustion chamber wall 202 is formed as the inlet portion 67A of the combustion exhaust gas flow path 67 formed in the reforming portion 60 described above. The combustion exhaust gas generated in the combustion chamber 207 flows into the combustion exhaust gas flow path 67 from the inlet portion 67A of the combustion exhaust gas flow path 67.

At the lower end of the combustion chamber wall 202, a rectifying portion 203 extending toward the lower side of the combustion chamber 207 is formed. The rectifying unit 203 is formed in a conical shape whose diameter increases toward the upper side (downstream side) of the combustion chamber 207. The inside of the rectifying unit 203 and the inside of the combustion chamber wall 202 are hollow as an example. The inside of the rectifying unit 203 may be filled with a heat insulating material.

The combustion chamber wall 202 and the rectifying unit 203 are formed on the innermost pipe material 21 (see also FIG. 1) among the plurality of pipe materials 21 to 29 constituting the above-mentioned container 20. A pipe 150 is provided at the shaft core portion of the pipe material 21. The pipe 150 is fixed to the pipe material 21, and a spark plug 151 is inserted inside the pipe 150. As shown in FIG. 1, the upper end portion of the pipe 150 is led out upward from the end portion (upper end portion) of the pipe material 21 opposite to the rectifying portion 203 side, and the spark plug 151 is on the upper end side of the pipe 150. It is removably inserted inside the pipe 150 through the opening of the pipe 150.

The spark plug 151 has a conductive core material 152 and an insulating material 153 that covers the core material 152. The tip end portion (lower end portion) of the core material 152 is formed as an ignition electrode 154, and the portion above the tip end portion of the core material 152 is formed as a conductive portion 155. The lower end of the pipe 150 and the insulating material 153 protrudes from the tip of the rectifying section 203. Further, the ignition electrode 154 protrudes from the lower ends of the pipe 150 and the insulating material 153, and is arranged on the central axis of the combustion chamber 207. The ignition electrode 154 also serves as a frame rod for detecting a flame current. For a technique in which the ignition electrode also serves as a frame rod for detecting a flame current, for example, the technique described in Japanese Patent Publication No. 7-117241 is applied.

In addition to the combustion chamber 207, a fuel gas chamber 208 and an oxidant gas chamber 209 are formed inside the combustion chamber peripheral wall 201. The fuel gas chamber 208 is provided below the combustion chamber 207 adjacent to the combustion chamber 207. The fuel electrode exhaust gas discharged from the fuel electrode of the fuel cell stack 10 is supplied as fuel gas to the fuel gas chamber 208. The oxidant gas chamber 209 is provided around the fuel gas chamber 208. The air electrode exhaust gas discharged from the air electrode of the fuel cell stack 10 is supplied to the oxidant gas chamber 209 as an oxidant gas.

The inner cylinder wall 204 is formed in a cylindrical shape, and is provided coaxially with the combustion chamber peripheral wall 201 inside the combustion chamber peripheral wall 201. The inner cylinder wall 204 separates the fuel gas chamber 208 and the oxidant gas chamber 209. The opening on the combustion chamber 207 side of the inner cylinder wall 204 formed in the shape of a cylinder is covered with a top wall 222 and closed. The fuel gas chamber 208 is partitioned from the combustion chamber 207 by the top wall 222.

A cylindrical wall portion 232 is provided on the radial outer side of the tip portion (end portion on the combustion chamber 207 side) of the inner cylindrical wall 204, and the opening of the tubular wall portion 232 on the combustion chamber 207 side is the top wall 222. It is covered. That is, the top wall 222 covers the tip portions of the cylindrical wall portion 232 and the inner cylindrical wall portion 204. An outer peripheral oxidant gas chamber 242 is formed between the cylindrical wall portion 232 and the inner cylindrical wall 204. The outer peripheral oxidant gas chamber 242 has an annular shape and communicates with the oxidant gas chamber 209. The length of the tubular wall portion 232 in the cylindrical axial direction is shorter than that of the inner tubular wall 204, and the tapered wall portion 205 is formed so as to extend radially outward from the lower end of the tubular wall portion 232.

As shown in FIG. 5, a fuel gas nozzle 210 is formed on the inner cylinder wall 204. A plurality of fuel gas nozzles 210 are formed at intervals in the circumferential direction. The fuel gas nozzle 210 is a circular hole that penetrates the inner cylinder wall 204 in the radial direction. The plurality of fuel gas nozzles 210 are arranged at equal intervals.

As shown in FIGS. 6A and 6B, an oxidant gas nozzle 252 is formed in the cylindrical wall portion 232 at a position corresponding to the fuel gas nozzle 210. The oxidant gas nozzle 252 is a circular hole that penetrates the cylindrical wall portion 232 in the radial direction. The oxidant gas nozzle 252 has a larger diameter than the fuel gas nozzle 210. Further, an oxidant gas nozzle 252A is formed between the oxidant gas nozzles 252 adjacent to each other in the circumferential direction. The oxidant gas nozzle 252A is provided at a position where the fuel gas nozzle 210 is not formed.

The central axis S1 of the fuel gas nozzle 210 is arranged below the central axis S2 of the oxidant gas nozzle 252. When the fuel gas nozzle 210 is viewed from the direction of the central axis S1, a portion that does not overlap with the oxidant gas nozzle 252 is formed in the lower portion of the fuel gas nozzle 210 (see FIG. 7). Hereinafter, the non-overlapping portion of the fuel gas nozzle 210 is referred to as “non-overlapping portion 210A”, and the portion overlapping with the oxidant gas nozzle 252 is referred to as “overlapping portion 210B”.

In the present embodiment, the central axis S1 of the fuel gas nozzle 210 is arranged below the central axis S2 of the oxidant gas nozzle 252, and the central axis S1 and the central axis S2 are displaced. It may be placed above the above. Further, the central axis S1 and the central axis S2 may be shifted in the horizontal direction.

Further, as shown in FIG. 8, even if the fuel gas nozzle 210 has a larger diameter than the oxidant gas nozzle 252, the central axis S1 and the central axis S2 are aligned, and the fuel gas nozzle 210 and the oxidant gas nozzle 252 are coaxially arranged. good. In this case, a portion having a diameter larger than that of the oxidant gas nozzle 252 of the fuel gas nozzle 210 is a non-overlapping portion.

The fuel gas 165 supplied to the fuel gas chamber 208 is ejected from the fuel gas nozzle 210 to the outer peripheral oxidant gas chamber 242. The fuel gas 165 ejected to the outer peripheral oxidant gas chamber 242 hits the cylindrical wall portion 232 of the ejection destination in the non-overlapping portion 210A to generate turbulent flow. As a result, the oxidant gas 166 and the fuel gas 165 are stirred and mixed in the outer peripheral oxidant gas chamber 242, and the mixed mixed gas MG is ejected from the oxidant gas nozzles 252 and 252A to the combustion chamber 207.

The tapered wall portion 205 is provided in an annular shape around the tubular wall portion 232, and separates the combustion chamber 207 and the oxidant gas chamber 209. The tapered wall portion 205 is formed in a tapered shape whose diameter increases from the lower side to the upper side of the combustion chamber 207.

A plurality of tapered wall communication holes 211 are formed in the tapered wall portion 205. The plurality of tapered wall communication holes 211 are formed by holes penetrating the tapered wall portion 205 in the thickness direction. The plurality of tapered wall communication holes 211 are arranged concentrically and radially around the axis of the combustion chamber 207. That is, the plurality of tapered wall communication holes 211 includes a radial nozzle array in which a plurality of tapered wall communication holes 211 are arranged in the radial direction of the tapered wall portion 205, and a plurality of tapered walls at intervals in the circumferential direction of the tapered wall portion 205. It forms a circumferential nozzle row in which the communication holes 211 are lined up.

In each radial nozzle row, the spacing between the plurality of tapered wall communication holes 211 located on the radial outside of the tapered wall 205 is larger than the spacing between the plurality of tapered wall communication holes 211 located on the radial inside of the tapered wall 205. The one is narrower. As a result, in the concentric annular zone having the same width in the radial direction, the permeation flow rate of the tapered wall communication hole 211 of the oxidant gas is larger on the outer side in the radial direction than on the inner side in the radial direction.

As shown in FIG. 4, the oxidant gas 166 supplied to the oxidant gas chamber 209 is ejected from the tapered wall communication hole 211. The oxidant gas 166 ejected from the tapered wall communication hole 211 is ejected from the oxidant gas nozzles 252 and 252A described above, and is mixed with the mixed gas MG diffused from the radial inside to the outside of the tubular wall portion 232.

As shown in FIG. 4, a reforming flow path 66 of the reforming section 60 and an oxidizing agent gas flow path 68 are formed around the combustor 200. That is, of the quadruple cylindrical walls 61 to 64, the third and fourth cylindrical walls 63 and 64 from the inside are extended downward. A reforming flow path 66 of the reforming portion 60 is extended between the tubular wall 62 and the tubular wall 63, and between the tubular wall 63 and the tubular wall 64. , The oxidizing agent gas flow path 68 of the reforming portion 60 is extended and formed.

Further, a fuel gas chamber bottom wall 213 is provided at the bottom of the fuel gas chamber 208, and a tubular shape protruding toward the fuel cell stack 10 side (lower side) is provided at the center of the fuel gas chamber bottom wall 213. The connecting wall 214 is formed. The fuel gas 165, which is the fuel electrode exhaust gas discharged from the fuel electrode of the fuel cell stack 10, flows into the fuel gas chamber 208 through the communication passage 215 formed inside the connecting wall 214.

Further, an oxidant gas chamber peripheral wall 216 is provided on the outer peripheral portion of the oxidant gas chamber 209, and an oxidant gas chamber bottom wall 217 is provided on the bottom of the oxidant gas chamber 209. A communication hole 218 is formed in the bottom wall 217 of the oxidant gas chamber, and the oxidant gas 166, which is an air electrode exhaust gas discharged from the air electrode of the fuel cell stack 10, is passed through the communication hole 218 to the oxidant gas chamber. It flows into 209.

<Preheating part>
As shown in FIG. 4, the preheating section 100 (accommodating section) is composed of double tubular walls 101 and 102 provided below the combustion section 90. The inner tubular wall 101 of the double tubular walls 101 and 102 is composed of the lower part of the fifth pipe material 25, and the outer tubular wall 102 of the double tubular walls 101 and 102 is six. It is composed of the lower part of the second pipe material 26.

The preheating unit 100 is provided around the fuel cell stack 10 and accommodates the fuel cell stack 10. An inner space 104 is formed inside the preheating portion 100, and a preheating flow path 105 is formed between the double tubular walls 101 and 102 constituting the preheating portion 100.

The preheating flow path 105 is provided with a spiral member 106 spirally formed around the axial direction of the preheating portion 100, and the spiral member 106 causes the preheating flow path 105 to rotate in the axial direction of the preheating portion 100. It is formed in a spiral shape.

The upper end of the preheating flow path 105 is communicated with the oxidant gas flow path 68 of the reforming section 60 described above, and the lower end of the preheating flow path 105 is the bottom wall portion 34 and the bottom wall portion 35 shown in FIG. It is communicated with the oxidant gas intake 15 of the fuel cell stack 10 through the introduction path 37 formed between the two. As shown in FIG. 4, the preheating flow path 105 is formed with the upper side in the vertical direction as the upstream side, and the oxidation supplied to the preheating flow path 105 through the oxidant gas flow path 68 of the reforming section 60. The agent gas 164 flows from the upper side to the lower side in the vertical direction.

Further, inside the preheating unit 100, a fuel gas pipe 107 for connecting the above-mentioned reforming flow path 66 and the fuel gas intake port 16 (see FIG. 1) of the fuel cell stack 10 is provided. The reforming flow path 66 and the inside of the fuel gas pipe 107 communicate with each other through an orifice 98 provided at the lower end of the reforming flow path 66.

<Heat exchange section>
As shown in FIG. 2, the heat exchange section 110 is composed of triple tubular walls 111 to 113 provided around the reforming section 60 and the vaporization section 40 described above. The inner tubular wall 111 in the triple tubular walls 111 to 113 is composed of the seventh tubular material 27, and the central tubular wall 112 in the triple tubular walls 111 to 113 is composed of the eighth tubular material 28. The outer cylindrical wall 113 in the triple tubular walls 111 to 113 is composed of the ninth pipe material 29.
In the present embodiment, as an example, the heat exchange section 110 is configured by the triple tubular walls 111 to 113, but the heat exchange section is formed by another number (2 or less, 4 or more) of the tubular walls. It may be configured.

The triple tubular walls 111 to 113 constituting the heat exchange unit 110 have a gap between them. An oxidizing agent gas flow path 118 is formed between the inner tubular wall 111 and the central tubular wall 112, and between the outer tubular wall 113 and the central tubular wall 112, an oxidizing agent gas flow path 118 is formed. A combustion exhaust gas flow path 117 is formed.

The oxidant gas flow path 118 is provided with a spiral member 121 formed spirally around the axis of the heat exchange section 110, and the spiral member 121 allows the oxidant gas flow path 118 to be connected to the heat exchange section. It is formed in a spiral shape around the axis of 110. Similarly, the combustion exhaust gas flow path 117 is provided with a spiral member 120 spirally formed around the axial direction of the heat exchange unit 110, and the spiral member 120 allows the combustion exhaust gas flow path 117 to exchange heat. The portion 110 is formed in a spiral shape around the axial direction.

An oxidant gas supply pipe 122 (see FIG. 1) extending radially outward of the container 20 is connected to the lower end of the oxidant gas flow path 118. The gap between the connecting portion 31 and the connecting portion 32 is formed as a connecting flow path 38 extending in the radial direction of the container 20, and the upper end portion of the oxidant gas flow path 118 is described above via the connecting flow path 38. It communicates with the oxidant gas flow path 48 formed in the vaporization portion 40 of the above. The oxidant gas flow path 118 is formed with the lower side in the vertical direction as the upstream side, and the oxidant gas 164 supplied from the oxidant gas supply pipe 122 (see FIG. 1) to the oxidant gas flow path 118. Flows from the lower side to the upper side in the vertical direction.

Further, the gap between the connecting portion 32 and the connecting portion 33 is formed as a connecting flow path 39 extending in the radial direction of the container 20, and the upper end portion of the combustion exhaust gas flow path 117 is formed via the connecting flow path 39. It communicates with the combustion exhaust gas flow path 47 formed in the vaporization unit 40 described above. A gas discharge pipe 123 (see FIG. 1) extending radially outward of the container 20 is connected to the lower end of the combustion exhaust gas flow path 117. The combustion exhaust gas flow path 117 is formed with the upper side in the vertical direction as the upstream side, and the combustion exhaust gas 168 supplied from the combustion exhaust gas flow path 47 of the vaporization unit 40 is formed in the combustion exhaust gas flow path 117 from the upper side to the lower side in the vertical direction. Flow to the side.

<Insulation layer>
As shown in FIG. 1, the reforming unit 60, the vaporizing unit 40, and the heat exchange unit 110 are separated from each other in the radial direction of the container 20, and the reforming unit 60, the vaporizing unit 40, and the heat exchange unit 110 are separated from each other. A cylindrical heat insulating layer 130 is interposed between the two. The heat insulating layer 130 covers the vaporized portion 40 and the modified portion 60 from the outside.

<Insulation material>
The heat insulating material 140 has a cylindrical main body portion 141, a disk-shaped upper portion 142 and a lower portion 143, and covers the container 20. That is, the main body portion 141 is provided around the container 20 and covers the container 20 from the outside. The upper portion 142 covers the main body portion 141 from the upper side in the vertical direction, and is provided around the upper portion of the container 20. The upper portion 142 is fixed by a fixing member 144 from the upper side in the vertical direction. The lower portion 143 covers the container 20 and the main body portion 141 from the lower side in the vertical direction. The surface of the heat insulating material 140 is covered with a covering sheet 145.

<Operation of fuel cell module>
Next, the operation of the fuel cell module M according to the first embodiment will be described.

When the raw fuel 161 (a mixture of the raw fuel and the reforming water) is supplied to the vaporization flow path 46 shown in FIG. 2 through the raw fuel supply pipe 50 shown in FIG. 1, the raw material 161 spirals. The vaporization flow path 46 formed in a shape flows from the upper side to the lower side in the vertical direction. At this time, in the vaporization unit 40, the combustion exhaust gas 168 discharged from the combustor 200 (see FIG. 4) flows through the combustion exhaust gas flow path 47 from the lower side to the upper side in the vertical direction. When the combustion exhaust gas 168 flows through the combustion exhaust gas flow path 47 adjacent to the vaporization flow path 46, heat is exchanged between the raw fuel 161 flowing through the vaporization flow path 46 and the combustion exhaust gas 168. Then, in the vaporization flow path 46, the raw material fuel 161 is vaporized, and the raw material fuel gas 162 shown in FIG. 3 is generated.

The raw fuel gas 162 vaporized in the vaporization flow path 46 passes through the orifice 82 formed inside the connecting pipe 81 and flows into the inner space 85 of the mixing portion 80 formed above the reforming portion 60. At this time, when the raw fuel gas 162 vaporized in the vaporization flow path 46 passes through the orifice 82 inside the connecting pipe 81, the flow velocity is increased to become a jet flow, and the facing wall portion 86 on the outer side in the radial direction in the mixing portion 80 Collide with. Then, the raw fuel gas 162 collides with the facing wall portion 86 to generate a turbulent flow, and the hydrocarbon gas and the steam contained in the raw fuel gas 162 are mixed.

The raw fuel gas 162 mixed in this way changes its direction from the radial outer side to the vertical lower side by colliding with the facing wall portion 86, and a plurality of orifices 84 formed at the inlet of the reforming flow path 66. It flows into the reforming flow path 66 through. Since the plurality of orifices 84 are arranged at regular intervals in the circumferential direction of the reforming flow path 66, the raw fuel gas 162 is introduced into the reforming flow path 66 by passing through the plurality of orifices 84. It is dispersed in the circumferential direction and flows in.

At this time, in the reforming unit 60, the combustion exhaust gas 168 discharged from the combustor 200 (see FIG. 4) flows through the combustion exhaust gas flow path 67 from the lower side to the upper side in the vertical direction. When the combustion exhaust gas 168 flows through the combustion exhaust gas flow path 67 adjacent to the reforming flow path 66, heat is exchanged between the raw fuel gas 162 flowing through the reforming flow path 66 and the combustion exhaust gas 168. Then, in the reforming flow path 66, the fuel gas 163 is generated from the raw fuel gas 162 by the reforming catalyst layer 70 by utilizing the heat of the combustion exhaust gas 168.

As shown in FIG. 4, the fuel gas 163 generated in the reforming flow path 66 passes through the orifice 98 and flows into the inside of the fuel gas pipe 107. Then, the fuel gas 163 is supplied to the fuel gas inlet 16 (see FIG. 1) of the fuel cell stack 10 through the fuel gas pipe 107.

On the other hand, at this time, in the heat exchange unit 110 shown in FIG. 2, the oxidant gas 164 is supplied to the oxidant gas flow path 118 through the oxidant gas supply pipe 122 (see FIG. 1). The oxidant gas 164 flows through the spirally formed oxidant gas flow path 118 from the lower side to the upper side in the vertical direction. At this time, in the heat exchange unit 110, the combustion exhaust gas 168 discharged from the combustor 200 (see FIG. 4) flows through the combustion exhaust gas flow path 117 from the upper side to the lower side in the vertical direction. The combustion exhaust gas 168 is discharged to the outside of the fuel cell module M through the gas discharge pipe 123 shown in FIG.

As shown in FIG. 2, when the combustion exhaust gas 168 flows through the combustion exhaust gas flow path 117 adjacent to the oxidant gas flow path 118, it is between the oxidant gas 164 flowing through the oxidant gas flow path 118 and the combustion exhaust gas 168. Heat is exchanged. Then, the temperature of the combustion exhaust gas 168 discharged to the outside of the fuel cell module M is lowered, and the heat radiation to the outside of the fuel cell module M is suppressed. On the other hand, the oxidant gas 164 absorbs the heat of the combustion exhaust gas 168 and is preheated. The oxidant gas 164 preheated in the heat exchange section 110 flows into the oxidant gas flow path 48 of the vaporization section 40 through the connecting flow path 38, and then the oxidant gas flow path 48 and modification of the vaporization section 40. The oxidizing agent gas flow path 68 (see FIGS. 3 and 4) of the portion 60 flows from the upper side to the lower side in the vertical direction.

In the vaporization unit 40 shown in FIG. 2, as described above, the combustion exhaust gas 168 discharged from the combustor 200 (see FIG. 4) flows through the combustion exhaust gas flow path 47 from the lower side to the upper side in the vertical direction. When the combustion exhaust gas 168 flows through the combustion exhaust gas flow path 47 adjacent to the oxidant gas flow path 48, heat is exchanged between the oxidant gas 164 flowing through the oxidant gas flow path 48 and the combustion exhaust gas 168, and the oxidant gas 164 Is further preheated.

Similarly, as shown in FIG. 3, in the reforming section 60, the combustion exhaust gas 168 discharged from the combustor 200 (see FIG. 4) flows through the combustion exhaust gas flow path 67 from the lower side to the upper side in the vertical direction. When the combustion exhaust gas 168 flows through the combustion exhaust gas flow path 67 on the opposite side of the oxidizing agent gas flow path 68 sandwiching the reforming flow path 66, the oxidant gas 164 and the combustion exhaust gas 168 flowing through the oxidant gas flow path 68 are changed. Heat is exchanged via the quality channel 66 (modified catalyst layer 70), which also preheats the oxidizing agent gas 164.

The oxidant gas 164 preheated by flowing through the oxidant gas flow path 68 in this way flows into the preheating flow path 105 shown in FIG. 4, and the spirally formed preheating flow path 105 is vertically upward. Flows downward from. The oxidant gas 164 flowing through the preheating flow path 105 is further preheated by the heat of the fuel cell stack 10. Then, the oxidant gas 164 preheated in the preheating flow path 105 is supplied to the oxidant gas intake 15 (see FIG. 1) of the fuel cell stack 10.

As described above, the fuel gas (reform gas) is supplied to the fuel gas inlet 16 of the fuel cell stack 10 shown in FIG. 1, and the oxidant gas inlet 15 of the fuel cell stack 10 is oxidized. When the agent gas is supplied, the fuel cell stack 10 generates electricity in each cell 12 by an electrochemical reaction between the fuel gas and the oxidizing agent gas. Further, each cell 12 generates heat with power generation.

When the fuel cell stack 10 is activated in this way, the fuel electrode exhaust gas is discharged from the fuel electrode of the fuel cell stack 10 and the air electrode exhaust gas is discharged from the air electrode of the fuel cell stack 10. The fuel electrode exhaust gas includes fuel gas that was not used for power generation in the fuel cell stack 10, and similarly, the air electrode exhaust gas includes an oxidant gas that was not used for power generation in the fuel cell stack 10. Is included.

As shown in FIG. 4, the fuel electrode exhaust gas discharged from the fuel electrode of the fuel cell stack 10 is supplied as fuel gas to the fuel gas chamber 208 of the combustor 200 and discharged from the air electrode of the fuel cell stack 10. The resulting air electrode exhaust gas is supplied as an oxidant gas to the pair of oxidant gas chambers 209 of the combustor 200, respectively.

Then, as shown in FIG. 4, the fuel gas 165, which is the fuel electrode exhaust gas supplied to the fuel gas chamber 208, is ejected from the fuel gas nozzle 210 to the outer peripheral oxidizing agent gas chamber 242. A part (fuel gas 165 passing through the non-overlapping portion 210A) of the fuel gas 165 ejected from the fuel gas nozzle 210 hits the tubular wall portion 232 of the ejection destination to generate turbulence. As a result, the oxidant gas 166 and the fuel gas 165 are stirred and mixed in the outer peripheral oxidant gas chamber 242, and the mixed mixed gas MG is ejected from the oxidant gas nozzles 252 and 252A to the combustion chamber 207. The mixed gas MG is ejected from the oxidizing agent gas nozzles 252 and 252A in the radial direction and diffused from the radial inside to the outside of the combustion chamber 207.

Further, the oxidant gas 166, which is the air electrode exhaust gas supplied to the oxidant gas chamber 209, is ejected from the plurality of tapered wall communication holes 211. The oxidant gas 166 ejected from the plurality of tapered wall communication holes 211 is mixed with the mixed gas MG diffused from the radial inside to the outside of the tapered wall portion 205. The mixed gas in the combustion chamber 207 is ignited and burned by a spark formed between the ignition electrode 154 and the pipe 150 or the like.

Here, for example, when the air ratio is high and the flow rate of the oxidant gas 166 is excessive with respect to the flow rate of the fuel gas 165, the mixed gas ejected to the combustion chamber 207 at a position close to the oxidant gas nozzles 252 and 252A. Is burned and a flame 167 is generated. The jet of the oxidant gas 166 ejected from the tapered wall communication hole 211 located on the radial outer side of the tapered wall portion 205 is mixed with the combustion exhaust gas 168 generated by the combustion of the mixed gas and discharged from the combustion chamber 207.

On the other hand, when the flow rate of the fuel gas 165 is large and the air ratio is low, the oxidant gas 166 ejected from the tapered wall communication hole 211 located inside the tapered wall portion 205 in the radial direction among the plurality of tapered wall communication holes 211. Then, the oxygen required for combustion of the mixed gas is insufficient. In this case, the oxidant gas 166 ejected from the tapered wall communication hole 211 provided from the radial inside to the outside of the tapered wall portion 205 and the mixed gas MG ejected from the oxidant gas nozzle 252 are mixed. By being burned, a flame 167 is generated from the radial inside to the outside of the tapered wall portion 205. As described above, in the combustor 200 according to the first embodiment, the flame portion changes so as to maintain combustion even if the air ratio and the amount of combustion change.

In this way, a combustion reaction occurs in the combustion chamber 207, and the combustion exhaust gas 168 generated by this combustion reaction flows into the inlet portion 67A of the combustion exhaust gas flow path 67 along the rectifying section 203 shown in FIG. As described above, the combustion exhaust gas 168 flowing into the inlet portion 67A of the combustion exhaust gas flow path 67 includes the combustion exhaust gas flow path 67 of the reforming section 60, the combustion exhaust gas flow path 47 of the vaporization section 40 (see FIG. 3), and the connecting flow. After flowing through the combustion exhaust gas flow path 117 (see FIG. 2) of the passage 39 and the heat exchange unit 110, the fuel is discharged to the outside of the fuel cell module M through the gas discharge pipe 123 shown in FIG.

Next, the operation and effect of the first embodiment of the present invention will be described.

As described in detail above, according to the combustor 200 of the first embodiment, as shown in FIG. 6, the jet flow of the fuel gas 165 ejected from the fuel gas nozzle 210 passes through a part (non-overlapping portion 210A). The fuel gas 165) hits the tubular wall portion 232 of the jet destination. As a result, a turbulent flow is generated in the outer peripheral oxidant gas chamber 242, the oxidant gas 166 and the fuel gas 165 are stirred and mixed, and the mixed gas MG is transferred from the oxidant gas nozzles 252 and 252A to the combustion chamber 207. It is ejected. The ejected mixed gas MG has high combustibility because the mixing of the oxidant gas 166 and the fuel gas 165 is promoted.

Further, the mixed gas MG ejected from the oxidant gas nozzle 252 toward the radial outside is diffused from the radial inside to the outside of the combustion chamber 207. Therefore, when the air ratio is high and the flow rate of the oxidant gas 166 is excessive with respect to the flow rate of the fuel gas 165, the mixed gas MG ejected to the combustion chamber 207 is burned at a position close to the oxidant gas nozzles 252 and 252A. And a flame 167 is generated. On the other hand, when the flow rate of the fuel gas 165 is large and the air ratio is low, the unburned mixed gas MG is mixed with the oxidizing agent gas 166 ejected from the tapered wall communication hole 211 while moving outward in the radial direction and burned. As a result, flame 167 is generated from the radial inside to the outside of the tapered wall portion 205. In this way, even if the air ratio changes, the flame portion changes so as to maintain combustion, so that the flame does not blow out in a wide air ratio range and stable short flame combustion can be obtained.

Since the combustor 200 described above is applied to the fuel cell module M, the stack exhaust gas can be stably combusted by a single combustor 200 even when the air ratio fluctuates. As a result, the structure of the combustor 200 and its surroundings can be simplified, so that the fuel cell module M can be miniaturized and the cost can be reduced.

Further, since the vaporization section 40 and the reforming section 60 are each formed by a plurality of tubular walls, the structures of the vaporization section 40 and the reforming section 60 can be simplified, and the vaporization section 40 and the reforming section 60 can be simplified. The unit 60 can be miniaturized. Further, since the combustor 200, the reforming unit 60, and the vaporizing unit 40 are arranged coaxially, the fuel cell module M can be miniaturized in the radial direction.

[Test example]
In the combustor 200 of the present embodiment and the combustor C1 of the comparative example, the carbon monoxide concentration of the emitted combustion exhaust gas was measured by changing the ratio of the fuel gas to be supplied and the oxidant gas (air). In the combustor C1 of the comparative example, the fuel gas nozzle 210 and the oxidant gas nozzle 252 are arranged coaxially, and only that point is different from the present embodiment (non-coaxial), and the other configurations are the same. As shown in the graph of FIG. 9, in the combustor 200 of the present embodiment, the carbon monoxide concentration in the combustion exhaust gas becomes 0 in a wide range of combustion air ratios as compared with the combustor C1 of the comparative example. It can be seen that the combustibility is good.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.

FIG. 10 shows a partial top view (A) and a vertical sectional view (B) of the combustor 220 according to the second embodiment of the present invention. The combustor 220 according to the second embodiment is the outermost radial wall communication hole 211 formed in the tapered wall portion 205 with respect to the combustor 200 (see FIG. 6) according to the first embodiment. The opening sizes of the tapered wall communication hole 211A formed in the circumferential direction and the tapered wall communication hole 211B adjacent to the tapered wall communication hole 211A and formed in the radial direction inside the tapered wall communication hole 211A are different. The opening size of the tapered wall communication hole 211B is larger than that of the tapered wall communication hole 211C formed in the radial inside thereof, and the opening size of the oxidant gas nozzle 21A is larger than the opening size of the tapered wall communication hole 211B. It has become.

As described above, by reducing the opening size of the tapered wall communication hole 211 on the radial inside and increasing the radial outside, the flow rate of the oxidant gas ejected from the radial outside of the combustion chamber 207 increases. As a result, when the air ratio is high and the flow rate of the oxidant gas 166 is excessive with respect to the flow rate of the fuel gas 165, the oxidant gas unnecessary for combustion is discharged together with the combustion exhaust gas at a position far from the flame, and the flame is discharged. The disappearance can be suppressed.

When the air ratio is low, the supply amount of the oxidant gas can be reduced at a position close to the oxidant gas nozzle 252 inside the combustion chamber 207 in the radial direction to reduce the combustion speed. As a result, it is possible to prevent the combustor 220 from deteriorating due to local overheating of the combustor 220 due to the concentration of flames.

In the present embodiment, the opening size of the tapered wall communication hole 211 is changed so that the flow rate of the oxidant gas ejected from the radial outside of the combustion chamber 207 is increased, but the opening size is not changed. As shown in FIG. 11, the number of tapered wall communication holes 211A formed in the outermost circumferential direction in the radial direction may be increased. In FIG. 11, the number of tapered wall communication holes 211A is twice the number of tapered wall communication holes 211B and 211C. Even in this case, when the air ratio is high, the oxidant gas unnecessary for combustion can be discharged together with the combustion exhaust gas at a position far from the flame, and the extinction of the flame can be suppressed. Further, when the air ratio is low, the combustion speed can be lowered at a position close to the oxidant gas nozzle 252, and deterioration of the combustor 220 due to local overheating of the combustor 220 can be suppressed.

The combustors 200 and 220 according to the first and second embodiments described above are more preferably applied to the fuel cell module, but may be applied to devices other than the fuel cell module, for example. Further, it may be used as a combustor for burning a low-calorie gas such as biogas.

Further, the present invention is not limited to the above, and it is needless to say that the present invention can be variously modified and implemented within a range not deviating from the gist thereof.

M Fuel cell module, 10 Fuel cell stack 40 Vaporizing part, 41, 42, 43 Cylindrical wall 45 Insulated space, 46 Vaporizing flow path 47 Combustion exhaust gas flow path, 60 Remodeling part, 61, 62, 63 Cylindrical wall 65 Insulated space, 66 Vaporization flow path, 67 Combustion exhaust gas flow path 200, 220 Combustor, 201 Combustion chamber peripheral wall 205 Tapered wall part 204 Inner cylinder wall (fuel gas chamber partition wall)
207 Combustion chamber 208 Fuel gas chamber, 209 Oxidizing agent gas chamber 210 Fuel gas nozzle, 210A Non-overlapping part, 210B Overlapping part 211 Tapered wall communication hole, 222 Top wall 232 Cylindrical wall part (Oxidizing agent gas chamber partition wall)
242 Peripheral oxidizer gas chamber (oxidizer gas chamber)
252 Oxidizing agent gas nozzle

Claims (9)

A combustion chamber formed inside the peripheral wall of a tubular combustion chamber in which a mixed gas containing a mixture of fuel gas and oxidant gas is burned.
The oxidant gas is supplied from the outside adjacent to one end side of the cylinder shaft of the combustion chamber, and the oxidant gas chamber is partitioned from the combustion chamber by the partition wall of the oxidant gas chamber.
A fuel gas chamber arranged inside the oxidant gas chamber in the radial direction, to which the fuel gas is supplied from the outside, and a fuel gas chamber partitioned from the oxidant gas chamber by a fuel gas chamber partition wall.
An oxidant gas nozzle that penetrates the partition wall of the oxidant gas chamber and communicates the combustion chamber and the oxidant gas chamber.
The overlapping portion that penetrates the fuel gas chamber partition wall and overlaps with the oxidant gas nozzle in the penetration direction, and the fuel gas ejection destination is the surface of the oxidant gas chamber partition wall on the oxidant gas chamber side. A fuel gas nozzle having a non-overlapping portion that does not overlap with the oxidizing agent gas nozzle and discharging the fuel gas to the oxidizing agent gas chamber.
Combustor equipped with. The combustor according to claim 1, wherein the fuel gas nozzle and the oxidant gas nozzle are non-coaxial. The oxidant gas chamber partition wall has a tubular tubular wall portion coaxially arranged with the combustion chamber peripheral wall, and the diameter of the tubular wall portion is expanded from the lower outer periphery of the tubular wall portion to the combustion chamber peripheral wall, and the combustion chamber is said to be the same. It has a tapered wall portion that is tapered so as to be convex toward one end.
The oxidant gas nozzle is formed in the tubular wall portion, and the tapered wall portion has a plurality of tapered wall communication holes that penetrate the tapered wall portion and communicate the oxidant gas chamber and the combustion chamber. The combustor according to claim 1 or 2, which is formed. The fuel gas chamber partition wall is formed to include a tubular inner cylinder wall arranged inside the tubular wall portion and a top wall covering the tip of the inner cylinder wall, and the fuel gas nozzle is formed inside the inner cylinder wall. The combustor according to claim 3, which is formed on a cylinder wall. In the concentric annular zone having the same width in the radial direction of the combustion chamber, the tapered wall communication hole has a larger permeation flow rate of the oxidant gas through the tapered wall communication hole on the outer side in the radial direction than on the inner side in the radial direction. The combustor according to claim 3 or 4, which is formed in. The tapered wall communication holes are formed in a plurality of concentric rows, and the number of the tapered wall communication holes in the radial outer row is larger than the number of the tapered wall communication holes in the radial inner row. , The combustor according to any one of claims 3 to 5. The tapered wall communication holes are formed in a plurality of concentric rows, and the opening size of the tapered wall communication holes in the radial outer row is larger than the opening size of the tapered wall communication holes in the radial inner row. The combustor according to any one of claims 3 to 6. A fuel cell stack that generates electricity by an electrochemical reaction between fuel gas and oxidant gas,
The vaporization section where raw fuel is vaporized to generate raw fuel gas,
The reforming part where the fuel gas is generated from the raw fuel gas,
Combustion of stack exhaust gas, which is a mixture of fuel gas, which is the fuel electrode exhaust gas discharged from the fuel electrode of the fuel cell stack, and oxidant gas, which is the air electrode exhaust gas discharged from the air electrode of the fuel cell stack. The combustor according to any one of claims 1 to 7 and the combustor.
A fuel cell module equipped with. The combustor is provided above the fuel cell stack.
The reforming portion is provided above the combustor coaxially with the combustor, is composed of at least triple tubular walls having a gap between them, and is inside the triple tubular wall. The raw material fuel gas is reformed by utilizing the heat insulating space, the combustion exhaust gas flow path through which the combustion exhaust gas discharged from the combustor flows, and the heat of the combustion exhaust gas between the tubular wall and the fuel gas. Each has a reforming flow path in which
The vaporizing portion is provided above the reforming portion coaxially with the reforming portion, and is composed of at least three triple cylindrical or elliptical tubular walls having a gap between them. The raw material gas is vaporized by heat exchange with the heat insulating space, the combustion exhaust gas flow path through which the combustion exhaust gas flows, and the combustion exhaust gas between the inside and the cylindrical wall of the triple cylindrical wall, and the raw material fuel gas. Each has a vaporization channel in which
The fuel cell module according to claim 8.

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