Combustor and fuel cell system

Abstract

To suppress air pressure loss to stabilize combustion in a combustor.SOLUTION: A combustor that mixes and burns fuel gas and air includes a gas flow pipe having a closed end in the axial direction and having a side wall formed with a plurality of ejection holes for ejecting fuel gas flowing toward the end to the outside, a guide tube having an open end in the axial direction and arranged coaxially with the gas flow pipe so as to surround the gas flow pipe and guiding air between the gas flow pipe and the gas flow pipe so as to flow toward the tip, and an igniter that ignites mixed gas of the fuel gas ejected from the ejection hole between the guide pipe and the air circulated between the gas flowing pipe and the guide pipe.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a combustor and a fuel cell system. [Background technology]

[0002] Conventionally, combustors that mix and burn fuel gas and air have been proposed. For example, Patent Document 1 describes a combustor that includes a fuel cell that generates power using fuel gas and oxidant gas, and a combustor that mixes and burns anode offgas (fuel gas) discharged from the anode of the fuel cell and cathode offgas (air) discharged from the cathode of the fuel cell. In the combustor of Patent Document 1, a plurality of ejection holes for the cathode offgas are formed so as to eject the cathode offgas obliquely across a plurality of ejection holes for the anode offgas. Patent Document 2 describes a combustor that arranges a swirl plate with a plurality of inclined holes inclined to the flow direction of the air in an air flow path, thereby making the air passing through the inclined holes a swirling flow. Patent Document 3 describes a combustor that promotes the mixing of the fuel gas and the air by supplying air and the fuel gas in the same direction and then ejecting the air from a direction perpendicular to the ejection direction of the fuel gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-181840 A [Patent Document 2] JP 2016-118353 A [Patent Document 3] JP 2017-33869 A Summary of the Invention [Problem to be solved by the invention]

[0004] Since each of the combustors described above performs diffusion combustion, it is necessary to make the air flow rate larger than the fuel gas flow rate in order to stabilize the combustion. However, in a configuration in which air is ejected from a plurality of ejection holes, such as the combustors of Patent Documents 1 and 2, the pressure loss in the air flow path increases. Also, in the combustor of Patent Document 3, the air flow path is bent so that the ejection direction of the air is perpendicular to the ejection direction of the fuel gas, so the pressure loss increases. If the air pressure loss increases in this way, it becomes necessary to enlarge the air blower to ensure the air flow rate, which may increase noise and costs.

[0005] A main object of the present invention is to stabilize combustion in a combustor by suppressing air pressure loss. [Means for solving the problem]

[0006] In order to achieve the above-mentioned main object, the present invention adopts the following means.

[0007] The combustor of the present invention comprises: A combustor that mixes and burns fuel gas and air, a gas flow pipe having a closed end in an axial direction and a plurality of ejection holes formed in a side wall thereof for ejecting the fuel gas that has flowed toward the end to the outside; a guide tube having an open axial end and arranged coaxially with the gas flow pipe so as to surround the gas flow pipe, the guide tube guiding air to flow between the gas flow pipe and the guide tube toward the end; an ignition device that ignites a mixed gas of the fuel gas ejected from the ejection hole into the guide pipe and the air that flows between the gas flow pipe and the guide pipe; The gist of the project is to provide the following:

[0008] In the combustor of the present invention, an ignition device ignites a mixed gas of fuel gas ejected from the ejection hole of the gas flow pipe to the guide pipe and air flowing between the gas flow pipe and the guide pipe, and combusts the gas. Therefore, there is no need for the air to pass through the ejection hole or to bend its flow direction, and since the tip of the guide pipe is open, the flow of the mixed gas and its combustion gas can be aligned with the flow direction of the air, so that the pressure loss of the air can be reduced. In addition, the fuel gas can be ejected perpendicular to the air and forcibly mixed with it, so that the fuel gas and the air can be mixed efficiently. Therefore, the pressure loss of the air can be suppressed and the combustion in the combustor can be stabilized.

[0009] In the combustor of the present invention, the guide pipe may have an extension portion extending parallel to the axial direction so that the cross-sectional area of ​​the space between the guide pipe and the gas flow pipe is larger than the cross-sectional area of ​​the gas flow pipe, and an expanding portion continuing from the extension portion and expanding in diameter from a portion facing the gas flow pipe toward the tip. In this way, a larger amount of air than the combustion gas can be circulated to increase the flow rate of the air, thereby improving the mixing efficiency and stabilizing the combustion. In addition, the mixed gas can be diffused to reduce the flow rate of the mixed gas, thereby preventing the flame length from becoming longer and reducing the combustion range. This prevents the object to be heated from becoming locally hot, and allows the object to be heated appropriately.

[0010] In the combustor of the present invention, the guide pipe may have a notch formed on an edge of a tip end, and the ignition device may be disposed radially outward of the guide pipe and ignite the mixed gas by discharging electricity into the guide pipe through the notch. In this way, ignition can be reliably performed at a position closer to a place where the fuel gas and the air are mixed.

[0011] In the combustor of the present invention, the gas flow pipe may be configured such that the plurality of ejection holes are formed in a plurality of pairs at equally spaced intervals in a circumferential direction and at positions facing each other in a radial direction, whereby the fuel gas can be ejected evenly into the space between the gas flow pipe and the guide pipe, thereby preventing unevenness in the concentration of the mixed gas, and thus making the combustion more stable.

[0012] The fuel cell system of the present invention comprises: a fuel cell stack that generates power using a reformed gas containing hydrogen and an oxidant gas containing oxygen; a reformer that reforms a raw fuel gas to generate a reformed gas; any one of the combustors described above that combusts a mixed gas of fuel gas and air as off-gas discharged from the fuel cell stack and supplies the combustion gas toward the reformer; The gist of the invention is to provide the following:

[0013] The fuel cell system of the present invention includes a fuel cell stack, a reformer, and any one of the combustors described above. Therefore, as described above, it is possible to suppress air pressure loss and stabilize combustion in the combustor, and therefore it is possible to appropriately raise the temperature of the reformer and ensure a stable supply of reformed gas. [Brief description of the drawings]

[0014] [Figure 1] 1 is a diagram showing an outline of the configuration of a fuel cell system 10. FIG. [Diagram 2] FIG. 2 is a diagram showing an outline of the configuration of a combustion unit 22. [Diagram 3] FIG. 2 is a perspective view of a combustor 30 disposed in the bulkhead 26. [Figure 4] FIG. 2 is a perspective view including a partial cross section of a combustor 30. [Diagram 5] 2 is an explanatory diagram showing the state of combustion in a combustor 30. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Next, an embodiment of the present invention will be described.

[0016] Fig. 1 is a diagram showing an outline of the configuration of a fuel cell system 10, and Fig. 2 is a diagram showing an outline of the configuration of a combustion unit 22. As shown in Fig. 1, the fuel cell system 10 of this embodiment includes a power generation module 20, a raw fuel gas supply device 40, an air supply device 50, a reforming water supply device 60, and an exhaust heat recovery device 70.

[0017] The power generation module 20 includes a fuel cell stack 21 and a combustion unit 22, and the fuel cell stack 21 and the combustion unit 22 are housed in a box-shaped module case 29 formed of a heat insulating material. The fuel cell stack 21 is configured as a solid oxide fuel cell in which a plurality of fuel cells are arranged, each including a solid electrolyte made of an oxygen ion conductor, an anode provided on one side of the solid electrolyte, and a cathode provided on the other side of the solid electrolyte. The fuel cell stack 21 generates power by an electrochemical reaction between hydrogen in a fuel gas (reformed gas) supplied to the anode and oxygen in air (oxidant gas) supplied to the cathode. An output terminal of the fuel cell stack is connected to a power line connecting a commercial power source and a load via a power conditioner (not shown). The DC power output from the fuel cell stack 21 to the output terminal is added to the AC power from the commercial power source through voltage conversion and DC / AC conversion by the power conditioner, and then supplied to the load.

[0018] 2, the combustion unit 22 includes a vaporizer 23, a reformer 24, and a combustor 30. The vaporizer 23 and the reformer 24 are disposed in a combustion chamber 25 through which the combustion gas flows, and the combustor 30 is disposed in a partition wall 26 between the combustion chamber 25 and the air introduction chamber 27 through which air is introduced. The vaporizer 23 evaporates reforming water to generate steam and preheats raw fuel gas (e.g., natural gas or LP gas). The reformer 24 generates fuel gas (reformed gas) from the raw fuel gas and steam. The vaporizer 23 and the reformer 24 may be integrally configured. The combustor 30 supplies heat (combustion gas) required for the generation of steam in the vaporizer 23 and the steam reforming reaction in the reformer 24 to the combustion chamber 25.

[0019] The raw fuel gas supplying device 40 includes a raw fuel gas supplying pipe 41 that connects a gas supplying source 1 that supplies raw fuel gas to a combustion unit 22 (vaporizer 23), and a raw fuel gas supplying valve 42 (two-valve), a raw fuel gas pump 43, and a desulfurizer 44 that are provided in this order from the gas supplying source 1 side to the raw fuel gas supplying pipe 41. The raw fuel gas supplying device 40 supplies raw fuel gas from the gas supplying source 1 to the combustion unit 22 via the desulfurizer 44 by operating the raw fuel gas pump 43 with the raw fuel gas supplying valve 42 open. The desulfurizer 44 removes sulfur contained in the raw fuel gas, and may employ, for example, a room temperature desulfurization method that removes sulfur compounds by adsorbing them to an adsorbent such as zeolite. The raw fuel gas supplied to the vaporizer 23 of the combustion unit 22 is preheated by the vaporizer 23, and then supplied to the reformer 24, where it is reformed into a fuel gas (reformed gas). The reformed fuel gas is then supplied to the anode of the fuel cell stack 21 .

[0020] The air supply device 50 includes an air supply pipe 52 that connects a filter 51 that communicates with the outside air and the fuel cell stack 21, and an air blower 53 that is provided in the air supply pipe 52. The air supply device 50 supplies air sucked in through the filter 51 to the cathode of the fuel cell stack 21 by operating the air blower 53.

[0021] The reforming water supply device 60 includes a reforming water tank 61 that stores reforming water, a reforming water supply pipe 62 that connects the reforming water tank 61 and the combustion unit 22 (vaporizer 23), and a reforming water pump 63 provided on the reforming water supply pipe 62. The reforming water supply device 60 operates the reforming water pump 63 to supply the reforming water in the reforming water tank 61 to the vaporizer 23 of the combustion unit 22. The reforming water supplied to the vaporizer 23 is converted into steam by the vaporizer 23 and used for the steam reforming reaction in the reformer 24.

[0022] The combustor 30 is supplied with fuel gas (fuel off-gas, anode off-gas, solid arrow in FIG. 2) that has passed through the fuel cell stack 21 (each fuel cell unit) and air (oxidant off-gas, cathode off-gas, dashed arrow in FIG. 2), and combusts the mixed gas. The combustor 30 supplies the combustion gas generated by the combustion of the mixed gas to the vaporizer 23 and the reformer 24 in the combustion chamber 25. The supplied combustion gas flows through the combustion chamber 25 (dotted arrow in FIG. 2) and is discharged from the exhaust hole 25a of the combustion chamber 25 into the module case 29. The discharged combustion exhaust gas is supplied to the heat exchanger 75 via the combustion catalyst 28. The combustion catalyst 28 is an oxidation catalyst that catalytically re-burns the off-gas that remains unburned in the combustor 30.

[0023] The exhaust heat recovery device 70 includes a hot water tank 71 for storing hot water, a heat exchanger 75, a circulation pipe 72 for connecting the hot water tank 71 and the heat exchanger 75 to form a circulation path for the hot water, and a circulation pump 73 provided on the circulation pipe 72. The exhaust heat recovery device 70 operates the circulation pump 73 to circulate the hot water, thereby taking out the hot water from the lower part of the hot water tank 71, heating the hot water by heat exchange with the combustion exhaust gas in the heat exchanger 75, and returning the heated hot water to the upper part of the hot water tank 71. The heat exchanger 75 is connected to the reforming water tank 61 via a condensed water supply pipe 76 and is communicated with the outside air via an exhaust pipe 77. The combustion exhaust gas supplied to the heat exchanger 75 is cooled by heat exchange with the hot water, and the water vapor component is condensed and collected in the reforming water tank 61 via the condensed water supply pipe 76 and a water purifier (not shown). The remaining exhaust gas is exhausted to the outside air via the exhaust pipe 77.

[0024] Here, a detailed configuration of the combustor 30 will be described. Fig. 3 is a perspective view of the combustor 30 disposed in the partition wall 26, and Fig. 4 is a perspective view including a partial cross section of the combustor 30. The combustor 30 includes a fuel gas flow pipe 32, a guide pipe 34, and an ignition plug 38.

[0025] The fuel gas flow pipe 32 is configured as a cylindrical member with its front and rear ends in the axial direction closed. The fuel gas flow pipe 32 is connected to the fuel gas introduction pipe 31 extending vertically so as to introduce the fuel gas (combustion off-gas) that has passed through the fuel cell stack 21 to the combustion unit 22 side, and is arranged so that its axial direction is horizontal. The rear end of the fuel gas flow pipe 32 is located inside the air introduction chamber 27, and the front end of the fuel gas flow pipe 32 is located closer to the combustion chamber 25 than the partition wall 26. The fuel gas flow pipe 32 has a plurality of ejection holes 33 formed in a side wall near the front end, penetrating in the radial direction. All of the ejection holes 33 have an elliptical shape with the axial direction of the fuel gas flow pipe 32 as the longitudinal direction, and are formed at positions spaced the same distance from the front end of the fuel gas flow pipe 32. The ejection holes 33 are formed in pairs at equal intervals in the circumferential direction and at positions facing each other in the radial direction so as to penetrate in the radial direction, and as an example, five pairs (a total of ten) of ejection holes 33 are provided in the radial direction. Therefore, the fuel gas that flows in the axial direction through the fuel gas flow pipe 32 toward the tip changes its flow direction to the radial direction so as to bend near the tip, and is ejected to the outside from the multiple ejection holes 33.

[0026] The guide pipe 34 is configured as a cylindrical member (annular member) with its front and rear ends in the axial direction being open. The guide pipe 34 is disposed coaxially with the fuel gas flow pipe 32 so as to surround the fuel gas flow pipe 32, and forms an annular flow passage 30a between the guide pipe 34 and the outer circumferential surface of the fuel gas flow pipe 32. The guide pipe 34 guides air (oxidant off-gas) introduced into the air introduction chamber 27 by an air introduction pipe (not shown) to flow from the rear end into the flow passage 30a, and guides the air to flow through the flow passage 30a to the front end side in parallel with the flow direction of the fuel gas in the fuel gas flow pipe 32. In this embodiment, the fuel gas flow pipe 32 and the guide pipe 34 are configured so that the cross-sectional area of ​​the annular flow passage 30a is larger than the cross-sectional area of ​​the fuel gas flow pipe 32, and a larger amount of air than the fuel gas can be supplied (flowed).

[0027] The guide pipe 34 has different shapes at the front and rear ends, with an extension portion 34a extending parallel to the axial direction with a constant inner and outer diameter formed at the rear end, and an expanded diameter portion 34b continuing from the extension portion 34a and expanding in diameter toward the front end formed at the front end. The extension portion 34a is formed to have a diameter that makes the cross-sectional area of ​​the flow passage 30a larger than the cross-sectional area of ​​the fuel gas flow pipe 32. The extension portion 34a is supported so as to be fitted into the opening of the partition wall 26, and extends to the vicinity of the center position in the longitudinal direction of the ejection hole 33 of the fuel gas flow pipe 32. That is, the guide pipe 34 has the extension portion 34a extending parallel to the axial direction up to a position facing the ejection hole 33 of the fuel gas flow pipe 32, and the expanded diameter portion 34b has a larger inner and outer diameter toward the front end than the position facing the ejection hole 33. Furthermore, the guide pipe 34 has a notch 35 formed on the edge of the tip of the expanded diameter portion 34b so that a part of the circumferential direction penetrates through in the radial direction.

[0028] The ignition plug 38 is configured to ignite a mixed gas of the fuel gas ejected from the ejection hole 33 into the flow passage 30a and the air flowing through the flow passage 30a by discharging an electric discharge. The ignition plug 38 is disposed radially outside the guide tube 34, and discharges an electric discharge toward the inside of the guide tube 34 (radially inward) through the cutout 35.

[0029] FIG. 5 is an explanatory diagram showing the state of combustion in the combustor 30. As shown in the figure, the fuel gas introduced from the fuel gas introduction pipe 31 flows in the axial direction (horizontal direction) through the fuel gas flow pipe 32 and is ejected from the multiple ejection holes 33 radially outward so as to be perpendicular to the axial direction (solid line arrow in FIG. 5). Also, the air guided by the guide pipe 34 flows linearly from the air introduction chamber 27 through the flow path 30a parallel to the axial direction (dash line arrow in FIG. 5). For this reason, it is not necessary to pass the air through an ejection hole smaller than the flow path or to bend the flow direction of the air, so that it is possible to prevent the flow resistance of the air from increasing. Then, the air flowing through the flow path 30a is mixed with the fuel gas ejected into the flow path 30a to generate a mixed gas. The guide pipe 34 has an open tip, and the flow direction of the generated mixed gas and its combustion gas can be aligned in the same direction as the flow direction of the air, so that it is possible to prevent the flow of the air in the flow path 30a from being affected. As a result, it is possible to reduce the pressure loss of the air. Furthermore, by ejecting the fuel gas from the ejection holes 33 so as to intersect at right angles with the air in the flow passage 30a, the fuel gas can be forcibly mixed with the air, thereby improving the mixing efficiency.

[0030] In addition, since the cross-sectional area of ​​the flow passage 30a is larger than that of the fuel gas flow pipe 32, a larger amount of air can be flowed than the fuel gas, and the flow rate of the air can be increased, so that the mixing efficiency can be improved. In addition, the fuel gas and the air are mixed at a location near the ejection hole 33, and the guide pipe 34 having the expanded diameter portion 34b is expanded at the tip side from the location facing the ejection hole 33 (mixing location), so that the cross-sectional area of ​​the tip is the largest. As a result, the mixed gas flows toward the combustion chamber 25 while diffusing, so that the flow rate decreases, and the air flow rate can be increased to increase the mixing efficiency up to the mixing location, and the flow rate can be quickly decreased after mixing. As a result, the flame length in the combustion of the mixed gas can be prevented from becoming long, the combustion range can be kept small, and the burner hole load can be reduced. This makes it possible to prevent the flame length from becoming too long and the flame from being blown away. Furthermore, the combustor 30 is disposed so as to supply combustion gas towards the combustion chamber 25 (reformer 24), and by shortening the flame length, it is possible to prevent localized heating of the reformer 24, thereby enabling the temperature of the reformer 24 to be appropriately increased. Furthermore, since localized heating can be prevented, it is possible to configure the combustor 30 and the reformer 24 with a shorter distance, thereby enabling the combustion unit 22 (power generation module 20) to be made more compact.

[0031] The ignition plug 38 ignites the mixed gas by discharging toward the mixing location on the radial inside through the notch 35. Therefore, the mixed gas can be reliably ignited by discharging toward the mixed gas at a location closer to the mixing location. The fuel gas flow pipe 32 has a plurality of ejection holes 33 that are equally spaced in the circumferential direction and formed in a plurality of pairs in the radial direction, which makes it easier to eject the fuel gas evenly into the flow passage 30a and perpendicular to the axial direction, thereby suppressing the occurrence of uneven concentration of the mixed gas and making the combustion more stable. In this way, the combustor 30 supplies the combustion gas of the flame resulting from the combustion of the mixed gas to the combustion chamber 25, so that the vaporizer 23 and the reformer 24 in the combustion chamber 25 can be appropriately heated.

[0032] In the combustor 30 of the fuel cell system 10 described above, a mixed gas of fuel gas that has been circulated through the fuel gas flow pipe 32 and ejected from the ejection hole 33, and air that has been circulated through the flow passage 30a between the guide pipe 34 and the fuel gas flow pipe 32, is ignited and combusted. This reduces the pressure loss of the air, making it possible to stabilize the combustion in the combustor 30. Furthermore, in the fuel cell system 10, the vaporizer 23 and the reformer 24 can be appropriately heated to stably supply the reformed gas.

[0033] Furthermore, since the mixed gas is diffused along the expanded diameter portion 34b, the flame length can be prevented from becoming too long, and the temperature of the reformer 24 can be raised appropriately.

[0034] Furthermore, since the ignition plug 38 discharges electricity into the guide tube 34 through the notch 35, the mixed gas can be ignited reliably.

[0035] Furthermore, since the plurality of ejection holes 33 are formed in pairs at equal intervals in the circumferential direction on the side wall of the fuel gas flow pipe 32, it is possible to prevent unevenness in the concentration of the mixed gas from occurring and to make the combustion more stable.

[0036] In the above-described embodiment, the multiple ejection holes 33 are formed in pairs at equal intervals in the circumferential direction of the side wall of the fuel gas flow pipe 32 and at positions facing each other in the radial direction, but this is not limited to the above, and the ejection holes 33 may be formed at different intervals or at positions not facing each other in the radial direction. In addition, the ejection holes 33 are not limited to being oval in shape, and may be other shapes such as circular or rectangular. In addition, the ejection holes 33 are not limited to being formed at positions at the same distance from the tip of the fuel gas flow pipe 32, and may be formed at positions at different distances. For example, the multiple ejection holes 33 may be formed in a staggered pattern at positions that are staggered in a side view.

[0037] In the embodiment, the guide tube 34 is provided with the notch 35, but the present invention is not limited to this and may not have the notch 35. In such a case, the ignition plug 38 may discharge from the opening at the tip of the guide tube 34 toward the inside of the guide tube 34, for example.

[0038] In the embodiment, the guide pipe 34 has the extension portion 34a and the enlarged diameter portion 34b, but is not limited thereto and may not have the enlarged diameter portion 34b. That is, the guide pipe 34 may be formed so as to extend with a constant inner and outer diameter over the entire axial length. Also, the cross-sectional area of ​​the flow passage 30a in the extension portion 34a is larger than the cross-sectional area of ​​the fuel gas flow pipe 32, but is not limited thereto and may be the same cross-sectional area for both. However, in order to ensure an air flow rate and stabilize combustion, the embodiment is preferable.

[0039] In the embodiment, the fuel gas flow pipe 32 extends in a direction perpendicular to the fuel gas introduction pipe 31, but the present invention is not limited to this, and the fuel gas flow pipe 32 may extend in the same direction as the fuel gas introduction pipe 31. For example, the axial direction of the fuel gas flow pipe 32 may be set to the vertical direction, the combustor 30 may be configured to supply the combustion gas (flame) upward, and the combustion chamber 25 may be disposed above the combustor 30.

[0040] In the embodiment, the fuel gas flow pipe 32 and the guide pipe 34 are cylindrical, but the present invention is not limited to this and may be formed into a polygonal cylindrical shape, an elliptical cylindrical shape, etc. In addition, the air introduced from the air introduction pipe to the air introduction chamber 27 flows through the guide pipe 34, but the present invention is not limited to this and the air introduction pipe and the guide pipe 34 may be connected and the air may be directly introduced from the air introduction pipe to the guide pipe 34.

[0041] In the embodiment, the combustor 30 is used in the fuel cell system 10 as an example, but the present invention is not limited to this and may be used in other systems.

[0042] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem will be described below. In the embodiment, the fuel gas flow pipe 32 corresponds to the "gas flow pipe", the guide pipe 34 corresponds to the "guide pipe", and the ignition plug 38 corresponds to the "ignition device". The extension portion 34a corresponds to the "extension portion", and the expanded diameter portion 34b corresponds to the "expanded diameter portion". The notch portion 35 corresponds to the "notch portion". In addition, the fuel cell stack 21 corresponds to the "fuel cell stack", the reformer 24 corresponds to the "reformer", and the combustor 30 corresponds to the "combustor".

[0043] Note that the correspondence between the main elements of the embodiment and the main elements of the invention described in the Means for Solving the Problem column does not limit the elements of the invention described in the Means for Solving the Problem column, since the embodiment is an example for specifically explaining the form for implementing the invention described in the Means for Solving the Problem column. In other words, the interpretation of the invention described in the Means for Solving the Problem column should be made based on the description in that column, and the embodiment is merely a specific example of the invention described in the Means for Solving the Problem column.

[0044] The above describes the form for carrying out the present invention using an embodiment, but the present invention is not limited to such an embodiment in any way, and it goes without saying that the present invention can be carried out in various forms without departing from the gist of the present invention. [Industrial Applicability]

[0045] The present invention can be used in the combustor manufacturing industry and the like. [Explanation of symbols]

[0046] 1 gas supply source, 10 fuel cell system, 20 power generation module, 21 fuel cell stack, 22 combustion unit, 23 vaporizer, 24 reformer, 25 combustion chamber, 25a exhaust hole, 26 partition wall, 27 air introduction chamber, 28 combustion catalyst, 29 module case, 30 combustor, 30a flow path, 31 fuel gas introduction pipe, 32 fuel gas flow pipe, 33 ejection hole, 34 guide pipe, 34a extension portion, 34b enlarged diameter portion, 35 notch portion, 37 spark plug, 40 raw fuel gas supply device, 41 raw fuel gas supply pipe, 42 raw fuel gas supply valve, 43 raw fuel gas pump, 44 desulfurizer, 50 air supply device, 51 filter, 52 air supply pipe, 53 air blower, 60 reforming water supply device, 61 reforming water tank, 62 Reformed water supply pipe, 63 reformed water pump, 70 exhaust heat recovery device, 71 hot water storage tank, 72 circulation piping, 73 circulation pump, 75 heat exchanger, 76 condensed water supply pipe, 77 exhaust piping.

Claims

1. A combustor that mixes and burns fuel gas and air, a gas flow pipe having a closed end in an axial direction and a plurality of ejection holes formed in a side wall thereof for ejecting the fuel gas that has flowed toward the end to the outside; a guide tube having an open axial end and arranged coaxially with the gas flow pipe so as to surround the gas flow pipe, the guide tube guiding air to flow between the gas flow pipe and the guide tube toward the end; an ignition device that ignites a mixed gas of the fuel gas ejected from the ejection hole into the guide pipe and the air that flows between the gas flow pipe and the guide pipe; Equipped with The guide tube has a notch formed on the edge of the tip, The ignition device is disposed radially outside the guide pipe and ignites the mixed gas by discharging electricity into the guide pipe through the notch. Combustor.

2. 2. The combustor of claim 1, The guide pipe has an extension portion extending parallel to the axial direction so that a cross-sectional area of ​​a space between the guide pipe and the gas flow pipe is larger than a cross-sectional area of ​​the gas flow pipe, and an enlarged diameter portion continuing from the extension portion and enlarging from a portion facing the ejection hole of the gas flow pipe toward the tip. Combustor.

3. The combustor according to claim 1 or 2, The gas flow pipe has a plurality of pairs of the ejection holes formed at equal intervals in a circumferential direction and at positions facing each other in a radial direction. Combustor.

4. a fuel cell stack that generates power using a reformed gas containing hydrogen and an oxidant gas containing oxygen; a reformer that reforms a raw fuel gas to generate a reformed gas; a combustor according to any one of claims 1 to 3, which combusts a mixed gas of fuel gas and air as off-gas discharged from the fuel cell stack, and supplies the combustion gas to the reformer; A fuel cell system comprising:

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