JP2010286130A - Two-mode combustion burner and fuel cell including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a burner capable of safely burning gas of which combustion speed is fast, such as off-gas and gas of which combustion speed is not so fast, such as city gas by using the one burner without causing the possibility of flashback, and a fuel cell using the burner. <P>SOLUTION: This two-mode combustion burner includes: a burner inner pipe having one bottomed end, the other opened end and a first gas flow passage formed inside; a burner outer pipe arranged on the outer side of the burner inner pipe, having one bottomed end on the same side as the burner inner pipe and the other end opened in the position in the vicinity of the opening of the burner inner pipe and forming a second gas flow passage between the burner outer pipe and the burner inner pipe; a first gas supply port opened in the first gas flow passage within the burner inner pipe in the vicinity of the bottom of the burner inner pipe; a second gas supply port opened in the second gas flow passage within the burner outer pipe in the vicinity of the bottom of the burner outer pipe; and ignition means arranged at a tip on the opening side of the burner inner pipe and the burner outer pipe. The fuel cell includes the burner. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a two-mode combustion burner and a fuel cell including the same, and more specifically, a fuel gas having a high combustion speed and a fuel gas having no combustion speed can be safely burned by one burner. The present invention relates to a two-mode combustion burner and a fuel cell including the same.

  For example, in fuel cells, hydrocarbons such as city gas and LP gas, for which supply systems have already been established, are used as raw fuel, and this is reformed by a reformer to produce fuel gas for fuel cells rich in hydrogen. Although the production is continuously performed, the reforming reaction in the reformer is an endothermic reaction by the catalyst. Therefore, to operate the reformer, the catalyst is heated using a burner, and the temperature is set. It is necessary to raise.

  As the fuel for the burner for heating the reformer, for example, as disclosed in Patent Document 1, off-gas that is an unreacted reformed gas discharged from the fuel cell is usually used. However, since the reformer is not operating at the start of the fuel cell operation, no offgas has yet been generated, and the offgas cannot be used as fuel for the burner that heats the reformer. Therefore, in Patent Document 2, for example, at the start of operation of the fuel cell, the burner is burned using raw fuel such as city gas or LP gas as raw fuel, and when the fuel cell reaches steady operation, It has been proposed to switch the fuel from city gas or LP gas to off-gas or reformed gas.

  However, compared to city gas or LP gas, the off gas or reformed gas contains a large amount of hydrogen, so the combustion rate is high and backfire is likely to occur. The city gas or LP gas and the off gas or reformed gas It was very difficult to burn both of them safely with a single burner.

JP 2002-250508 A JP 2004-214083 A

  The present invention has been made to solve the above-described disadvantages in the prior art. For example, a gas having a high combustion rate such as off-gas or reformed gas and a combustion rate such as city gas or LP gas are not so high. It is an object of the present invention to provide a burner capable of safely burning gas with one burner without fear of backfire, and a fuel cell using the burner.

  As a result of continual development efforts to solve the above-mentioned problems, the present inventors have improved the structure of the burner, and in one burner, fuel gas and combustion air are mixed in advance and supplied to the burner. It is rich in hydrogen by making it possible to switch between the premixed combustion mode that burns and burns and the premixed combustion mode that mixes and burns fuel gas and combustion air at the tip of the burner according to the type of fuel gas. The present invention was completed by finding that off-gas or reformed gas having a high combustion rate and city gas or LP gas having a low combustion rate can be safely burned with one burner without fear of flashback. did.

  That is, the present invention relates to a burner inner tube having a bottom at one end and an opening at the other end and forming a first gas flow path therein; a burner outer tube disposed outside the burner inner tube, Burner outer tube having one end on the same side as the tube having a bottom and the other end opened at a position close to the opening of the burner inner tube and forming a second gas flow path between the burner inner tube; A first gas supply port that opens to the first gas flow path in the burner inner pipe near the bottom of the burner; a second gas supply port that opens to the second gas flow path in the burner outer pipe near the bottom of the burner outer pipe; And by providing a two-mode combustion burner provided with ignition means disposed at the opening end of the burner outer tube, and by providing a fuel cell provided with the burner. To do.

  In the two-mode combustion burner of the present invention, it is desirable that the opening of the burner inner pipe is divided into a plurality of openings, and the plurality of openings are arranged in an island shape within the opening of the burner outer pipe. By arranging the opening of the burner inner tube and the opening of the burner outer tube in this way, the combustion air or fuel gas passing through the second gas supply path and going to the burner outer tube opening is arranged in an island shape. It can also go around the burner inner tube opening, mix well with the fuel gas or combustion air ejected from the burner inner tube opening at the tip of the burner, and ignite with appropriate ignition means to burn efficiently become.

  In a preferred embodiment of the two-mode combustion burner of the present invention, the openings of the burner inner tube and the burner outer tube are opened to the outside through a porous body having pores communicating with the front and back sufficient for gas to pass through. ing. In such a configuration, the two-mode combustion burner of the present invention becomes a surface combustion burner, and efficient and uniform heating can be realized by radiation from the burner surface and high-temperature combustion gas. The porous body provided at the opening of the burner inner tube and the burner outer tube may be made of any material as long as it can surface-combust a mixed gas of fuel gas and air. For example, a porous ceramic, an aggregate of ceramic fibers, a sintered body of metal fibers, a heat-resistant metal fiber knitted fabric, or a laminate of a heat-resistant metal fiber knitted fabric and a metal porous plate can be used. Among these, from the viewpoint of ease of processing and handling, it is most preferable to use a heat-resistant metal fiber knitted fabric.

  Further, in a preferred mode of the two-mode combustion burner of the present invention, the mixed gas of the first fuel gas and the combustion air is supplied to one or both of the first gas supply port and the second gas supply port. A combustion mode switching device that switches between a mixed combustion mode and a premixed combustion mode in which combustion air is supplied to either the first gas supply port or the second gas supply port and the second fuel gas is supplied to the other. Thus, the premixed combustion mode and the premixed combustion mode can be switched freely, and it is possible to safely use one burner without any fear of flashback, regardless of whether the fuel gas has a high combustion speed or not. Can be burned. Incidentally, when the two-mode combustion burner of the present invention is used for heating a reformer in a fuel cell, the first fuel gas is city gas or LP gas used as raw fuel gas of the fuel cell, The second fuel gas is off gas or reformed gas from the fuel cell.

  The two-mode combustion burner of the present invention is mainly used for heating the reformer of the fuel cell and exhibits its effect, but the use object of the two-mode combustion burner of the present invention is not limited to the fuel cell. The two-mode combustion burner of the present invention can be used in various devices under the circumstances where it is necessary to switch between a fuel gas having a high combustion speed and a fuel gas having a low combustion speed so as to be burned.

  According to the two-mode combustion burner of the present invention, since the combustion mode can be switched between the premixed combustion mode and the premixed combustion mode, for example, a fuel gas having a high combustion rate such as off-gas or reformed gas in a fuel cell Further, there is an advantage that fuel gas such as city gas or LP gas, which has a low combustion speed, can be safely burned with one burner without fear of backfire. Moreover, since the bimodal combustion burner of the present invention can realize bimodal combustion with a simple structure, it has the advantage that the manufacturing cost can be reduced. Furthermore, according to the fuel cell equipped with the two-mode combustion burner of the present invention, at the start of operation of the fuel cell, the reformer is heated by burning the burner using raw fuel gas such as city gas or LP gas, When the fuel cell reaches a steady operation, there is an advantage that the burner is burned using the off-gas or reformed gas from the fuel cell, and the reformer is continuously heated, so that the fuel cell can be continuously operated safely. can get.

It is a longitudinal cross-sectional view which shows an example of the two-mode combustion burner of this invention. It is X-X 'sectional drawing of FIG. FIG. 2 is a Y-Y ′ sectional view of FIG. 1. It is a conceptual diagram which shows the state which attached the combustion mode switching apparatus to the two-mode combustion burner of this invention. It is a conceptual diagram which shows an example of a fuel cell provided with the two-mode combustion burner of this invention.

  Hereinafter, the two-mode combustion burner of the present invention will be described with reference to the drawings, but the present invention is not limited to the illustrated one.

  FIG. 1 is a cross-sectional view showing an example of the two-mode combustion burner of the present invention. In FIG. 1, 1 is a two-mode combustion burner according to the present invention, 2 is a burner inner tube, and 3 is a first gas flow path formed inside the burner inner tube 2. 2a is a closing member that closes one end on the base side of the burner inner tube 2, and the bottom member 2b, 2b, 2b is an opening at the other end of the burner inner tube 2 on the front end side. It is. In this specification, the root side refers to the side far from the combustion chamber of the burner, and the tip side refers to the side close to the combustion chamber of the burner.

  Reference numeral 4 denotes a first gas supply port that opens to the first gas flow path 3 and is provided near the bottom of the burner inner tube 2. In this example, the burner inner tube 2 has a cylindrical shape, but the shape of the burner inner tube 2 is not limited to the cylindrical shape, and extends from the bottom side where the closing member 2a exists to the tip side where the openings 2b, 2b and 2b exist. Alternatively, it may be a truncated cone having a gradually increasing diameter.

  Reference numeral 5 denotes a burner outer pipe. The burner outer pipe 5 is arranged outside the burner inner pipe 2 and coaxially with the burner inner pipe 2, and forms a second gas flow path 6 between the burner inner pipe 2. ing. 5a is a closing member which closes the base side of the burner outer tube 5 which is one end on the same side as the burner inner tube 2 and has the burner outer tube 5 as a bottom, 5b is the other end of the burner outer tube 5 This is an opening on the tip side. As shown in the figure, the opening 5b of the burner outer tube 5 surrounds the periphery of the openings 2b, 2b, 2b of the burner inner tube 2 and opens on the same plane as the openings 2b, 2b, 2b of the burner inner tube 2. . However, the opening 5b of the burner outer tube 5 only needs to be opened at a position close to the openings 2b, 2b, 2b of the burner inner tube 2, and the opening position is not necessarily limited to the openings 2b, 2b of the burner inner tube 2. 2b may not be on the same plane. For example, the tip of the burner outer tube 5 may be slightly protruded from the tip of the burner inner tube 2, and the opening 5b may be positioned on the tip side of the openings 2b, 2b, 2b of the burner inner tube 2. On the contrary, the tip of the burner inner tube 2 is slightly protruded from the tip of the burner outer tube 5 so that the openings 2b, 2b, 2b of the burner inner tube 2 are closer to the tip than the opening 5b of the burner outer tube 5. May be located.

  Reference numeral 7 denotes a second gas supply port that opens to the second gas flow path 6, and is provided near the bottom of the burner outer tube 5. In this example, the burner outer tube 5 has a cylindrical shape similar to the burner inner tube 2, but the shape of the burner outer tube 5 is not limited to the cylindrical shape. For example, from the bottom side where the closing member 5a exists, the opening 5b, It may be a truncated cone having a diameter that gradually increases toward the tip side where 5b exists.

  Reference numeral 8 denotes a spark plug, which is arranged on the inner side of the burner inner tube 2 coaxially with the burner inner tube 2. Although most of the spark plug 8 is covered with an insulation shield, the electrode 9 is exposed at the tip. Reference numeral 10 denotes a ground electrode, and the electrode 9 and the ground electrode 10 constitute an ignition means disposed at the opening side end portions of the burner inner tube 2 and the burner outer tube 5. The ignition means is not limited to the combination of the electrode 9 and the ground electrode 10, but ignites the fuel gas and the combustion air ejected from the openings 2b, 2b, 2b and the opening 5b of the burner inner tube 2 and the burner outer tube 5. As long as it can be ignited, any mechanism may be employed.

  11 is a porous body having fine pores communicating with each other enough to allow gas to pass through, and is attached to the openings 2b, 2b, 2b and the opening 5b of the burner inner tube 2 and the burner outer tube 5. The fuel gas and combustion air that have passed through the first gas flow path 3 and the second gas flow path 6 are ejected from the openings 2b, 2b, 2b and the opening 5b to the outside of the burner through the porous body 11. Then, it is ignited by the ignition means composed of the electrode 9 and the earth electrode 10 and burns on the surface of the porous body 11. That is, the two-mode combustion burner 1 in this example is a surface combustion burner.

  Examples of the porous body 11 include porous ceramics, an aggregate of ceramic fibers, a sintered body of metal fibers, a heat-resistant metal fiber knitted fabric, or a laminate of a heat-resistant metal fiber knitted fabric and a metal porous plate. Although a body etc. can be used, since the heat-resistant metal fiber knitted fabric has good workability and is easy to handle, it is most preferable.

  Note that the two-mode combustion burner 1 of the present invention is not necessarily a surface combustion burner, and without providing the porous body 11, the combustion gas and the combustion air are opened to the openings 2b, 2b, 2b in the same manner as a normal burner. Alternatively, the gas may be ejected directly from the opening 5b and ignited by an ignition means composed of the electrode 9 and the earth electrode 10.

  12a and 12b are flanges attached to the burner inner tube 2 and the burner outer tube 5, respectively, and 13 is a fixing screw for fixing the burner outer tube 5 to the burner inner tube 2 using the flanges 12a and 12b. Reference numeral 14 denotes an attachment flange used when the two-mode combustion burner 1 of the present invention is attached to, for example, a reformer of a fuel cell.

  2 is a cross-sectional view taken along line X-X ′ of FIG. 1, and FIG. 3 is a cross-sectional view taken along line Y-Y ′ of FIG. 1. As shown in FIGS. 2 and 3, the first gas flow path 3 formed in the burner inner tube 2 has a plurality of divided openings 2 b, 2 b, 2 b. It is open to the outside. As shown in FIG. 3, the plurality of openings 2 b, 2 b, 2 b... Of the burner inner tube 2 are arranged in an island shape in the opening 5 b of the burner outer tube 5. The fuel gas or combustion air that has passed passes around the openings 2b, 2b, 2b,... As shown by the arrows in the figure before the opening 5b, and the openings 2b, 2b, 2b,. It will be ejected from the surroundings to the outside. Therefore, mixing with the combustion air or fuel gas ejected from the openings 2b, 2b, 2b... Is performed more quickly. In particular, when the porous body 11 is provided in the openings 2b, 2b, 2b... And the opening 5b, the fuel that has passed through the second gas flow path 6 due to the flow path resistance of the porous body 11 The wraparound of the gas or combustion air around the openings 2b, 2b, 2b,... Becomes more sufficient, and the gas ejected from the openings 2b, 2b, 2b,. , It will be mixed more efficiently.

  In the illustrated example, the openings 2b, 2b, 2b... Are arranged in the vertical cross section of the burner inner tube 2 with one opening at the center and eight equally around the opening, for a total of nine openings 2b. However, the number and arrangement of the openings 2b, 2b, 2b... Are not limited to those illustrated. The number may be 10 or more, or may be less than 7. In an extreme case, the central opening 2b is enlarged to the same diameter as the burner inner tube 2 to form one opening 2b. Also good. However, as shown in FIG. 3, the opening 2b of the burner inner tube 2 is divided into a plurality of parts and is arranged in an island shape in the opening 5b of the burner outer tube 5, so that the gas ejected from the opening 2b and the opening Since the gas ejected from 5b can be mixed efficiently, it is preferable. In addition, from the viewpoint of efficiently mixing the gas ejected from the opening 2b and the gas ejected from the opening 5b, it is preferable that the boundary lines of the openings 2b, 2b, 2b. Then, although the shape of the plurality of openings 2b, 2b, 2b... Is circular, it may be, for example, a rectangle, an ellipse, an arc, or a star. The island shape refers to a state in which a plurality of openings 2b, 2b, 2b... Are isolated from each other and divided by the openings 5b.

  Since the two-mode combustion burner 1 of the present invention has the above-described structure, for example, the first fuel gas mixed in advance from either the first gas inlet 4 or the second gas inlet 7, or both of them. Is burned by supplying a mixed gas of gas and combustion air, ejecting from the openings 2b, 2b, 2b... And / or the opening 5b, generating a spark between the electrode 9 and the ground electrode 10, and igniting and igniting. If it does, it will become a burner which burns in premix combustion mode. Further, either one of the second fuel gas and the combustion air is supplied from one of the first gas inlet 4 and the second gas inlet 7, and the other of the first gas inlet 4 and the second gas inlet 7 is supplied. Then, either the second fuel gas or the combustion air is supplied, and each of them is ejected from the openings 2b, 2b, 2b... Or the opening 5b, and a spark is generated between the electrode 9 and the ground electrode 10. When burned by ignition and ignition, the burner burns in the premixed combustion mode.

  Thus, when the two-mode combustion burner 1 of the present invention is burned in the premixed combustion mode, the second fuel gas is a fuel gas rich in hydrogen, such as off-gas or reformed gas, and having a high combustion rate. Even if it exists, in the 1st gas flow path 3 or the 2nd gas flow path 6, since it is not mixed with the combustion air yet and it is not the combustible mixed gas, the burner inner pipe 2 and the burner Even if the ignition means is ignited and ignited by the igniting means disposed at the opening end of the outer tube 5, there is no risk of the so-called backfire phenomenon in which the flame is drawn into the burner inner tube 2 or the burner outer tube 5, and it is safe. It is possible to burn it.

  When the two-mode combustion burner 1 of the present invention is burned in the premixed combustion mode, the second fuel gas supplied from the first gas inlet 4 or the second gas inlet 7 includes a combustible mixed gas and If it is in a range that should not occur, some combustion air may be mixed. As described above, when the second fuel gas and the combustion air are mixed in advance within a range that does not result in a combustible mixed gas, the burden of mixing at the burner tip portion can be reduced, and smoother premixing is possible. The advantage is that combustion is possible.

  In addition, when burning in the premixed combustion mode, the second fuel gas and the combustion air may be supplied from either the first gas inlet 4 or the second gas inlet 7, but the second gas ejected from the opening. Since it is preferable that the fuel gas is enveloped in the combustion air, the second fuel gas is preferably supplied mainly from the first gas inlet 4 into the first gas flow path 3.

  FIG. 4 is a conceptual diagram showing a state in which a combustion mode switching device is attached to the two-mode combustion burner 1 of the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals. In FIG. 4, 15 is a combustion mode switching device, 16 is a control device, 17 is a combustion air source, 18 is a first fuel gas source, 19 is a second fuel gas source, and 20a to 20f are open / close with a flow rate adjusting function. It is a valve. The control device 16 opens and closes the on-off valves 20a to 20f as appropriate, and the combustion air from the combustion air source 17, the first fuel gas from the first fuel gas source 18, and the first fuel gas from the second fuel gas source. Two fuel gases are supplied to the first gas supply port 4 and / or the second gas supply port 7 of the two-mode combustion burner 1 as appropriate, or both, and the two-mode combustion burner 1 is supplied to the premixed combustion mode or the premixed combustion mode. Can be burned in mode.

  For example, when the first fuel gas from the first fuel gas source 18 is used for combustion in the premixed combustion mode, the control device 16 sets the on-off valves 20a and 20b to “open”, and similarly the on-off valve 20c. And 20d are “open”, the combustion air from the combustion air source 17 and the first fuel gas from the first fuel gas source 18 are supplied to both the first gas supply port 4 and the second gas supply port 7. Supply. Only one of the on-off valve 20a or 20b and the corresponding one of the on-off valve 20c or 20d is “open”, and the combustion air and the first fuel gas are supplied to the first gas supply port 4 or the second gas supply. You may make it supply only to any one of the opening | mouths 7. FIG.

  As shown in FIG. 4, the pipeline from the first fuel gas source 18 through the on-off valve 20 c or 20 d is connected to the combustion air source 17 and the first gas supply port 4 or the second gas supply port 7 at the tip. Since the first fuel gas that has passed through the on-off valve 20c or 20d is mixed with the combustion air in the previous pipe line and becomes a combustible mixed gas because it is connected to the connecting pipe line, the first gas supply port 4 or the second gas supply port 7 is supplied. At this time, the amount of combustion air supplied from the combustion air source 17 is such that the flow rate is such that when mixed with the first fuel gas, the air ratio is 1.0 or higher. Of course, it is adjusted.

  Next, when the second fuel gas from the second fuel gas source 19 is used for combustion in the premixed combustion mode, the control device 16 "opens" one of the on-off valves 20a and 20b, and the other Is closed, the combustion air from the combustion air source 17 is supplied to either the first gas supply port 4 or the second gas supply port 7, and either the on-off valve 20e or 20f is turned to “ The second fuel gas from the second fuel gas source 19 is supplied to either the first gas supply port 4 or the second gas supply port 7 with “open” and the other “closed”. The combustion air and the second fuel gas respectively supplied to either the 1 gas supply port 4 or the second gas supply port 7 are mixed at the tip of the two-mode combustion burner 1 and burned in the premixed mode. become. At this time, the amount of combustion air supplied from the combustion air source 17 is such that the air ratio is 1.0 or more when mixed with the second fuel gas at the tip of the two-mode combustion burner 1. Of course, the flow rate is adjusted so as to obtain a ratio.

  Instead of supplying all of the air amount required for combustion to either the first gas supply port 4 or the second gas supply port 7, a part of the air amount is mixed with the second fuel gas, You may make it supply either the 1 gas supply port 4 or the 2nd gas supply port 7 to the other. That is, the control device 16 sets both the on-off valves 20a and 20b to “open”, and the combustion air passing through one of them is the combustion air alone, the first gas supply port 4 or the second gas supply port 7. Combustion air that is supplied to either one and passes through the other is mixed with the second fuel gas on the way, and supplied to either the first gas supply port 4 or the second gas supply port 7 as a mixed gas. . However, in this case, it goes without saying that the amount of combustion air mixed with the second fuel gas in the middle is set to a flow rate that is much lower than the air ratio.

  FIG. 5 is a conceptual diagram showing an example of a fuel cell including the two-mode combustion burner 1 of the present invention. In FIG. 5, 1 is a two-mode combustion burner according to the present invention, 15 is a combustion mode switching device, 21 is a reformer, 22 is a fuel cell body, 23 is a supply source of raw fuel such as city gas, and 24 is a supply of steam. 25, a catalyst filled in the interior of the reformer 21, 26 a hot air guide tube, 27 a carbon monoxide conversion / removal device, and 28 an air supply source such as a blower.

  At the start of the fuel cell, the combustion mode switching device 15 operates an on-off valve (not shown) to first mix the combustion air from the air supply source 28 and the source fuel from the source fuel supply source 23 in advance. Thus, the two-mode combustion burner 1 is supplied to the first gas supply port 4 and / or the second gas supply port 7 of the two-mode combustion burner 1, or both, and the two-mode combustion burner 1 is combusted in the premixed combustion mode.

  When the two-mode combustion burner 1 is ignited, the high-temperature combustion gas discharged from the two-mode combustion burner 1 is guided into the reformer 21 along the hot air guide pipe 26 of the reformer 21, and the inside of the reformer 21. The catalyst 25 is heated through a predetermined path. When the catalyst 25 is heated to a predetermined temperature, the raw fuel (for example, city gas) from the raw fuel supply source 23 is desulfurized by a desulfurizer (not shown) as necessary, and then supplied from the steam supply source 24. It is supplied to the reformer 21 together with the steam, and the reformer 21 starts operation. The reformed gas generated from the reformer 21 is supplied to the fuel cell main body 22 as fuel after the carbon monoxide is removed through the carbon monoxide conversion / removal device 27. The fuel cell body 22 is supplied with air from the air supply source 28 together with the reformed gas, and electricity is generated by an electrochemical reaction.

  When the fuel cell body 22 starts operation, off-gas, which is an unreacted reformed gas, is discharged from the fuel cell body 22, so the combustion mode switching device 15 switches the on-off valve (not shown) to perform two-mode combustion. The supply of raw fuel (for example, city gas) to the burner 1 is stopped, and instead, the off gas discharged from the fuel cell main body 22 is used as the first gas supply port 4 or the second gas supply port 7 of the two-mode combustion burner 1. Either of them is supplied as fuel gas. At the same time, the combustion mode switching device 15 supplies combustion air from the air supply source 28 to the other one of the first gas supply port 4 and the second gas supply port 7 of the two-mode combustion burner 1, and the two-mode combustion burner 1 is burned in the premixed combustion mode. The fuel gas supplied to either the first gas supply port 4 or the second gas supply port 7 in the premixed combustion mode may be a reformed gas that has passed through the carbon monoxide shift / removal unit 27. .

  The off gas and reformed gas discharged from the fuel cell main body 22 are rich in hydrogen and have a high combustion speed, but burn in the premixed combustion mode in the two-mode combustion burner 1 of the present invention, which may cause a backfire. It can be safely burned. Therefore, the fuel cell including the two-mode combustion burner 1 of the present invention can be stably and safely continuously operated from the start of the operation to the steady operation.

  As described above, according to the two-mode combustion burner of the present invention, fuel gas having a high combustion rate and fuel gas having a low combustion rate are burned safely with one burner without fear of backfire. Therefore, it is possible to obtain an excellent industrial advantage that it can be used for a wide range of applications including heating of a reformer in a fuel cell. In addition, since the two-mode combustion burner of the present invention has a simple structure, it can reduce the manufacturing cost and has industrial convenience that it can be used for a wide range of applications. Furthermore, according to the fuel cell equipped with the two-mode combustion burner of the present invention, it is possible to stably operate the reformer from the start of operation to the steady operation, and the fuel is stably supplied to the fuel cell. Therefore, it is possible to obtain the industrial advantage that the operation efficiency of the fuel cell is increased and the convenience is increased.

DESCRIPTION OF SYMBOLS 1 2 mode combustion burner 2 Burner inner pipe 2b, 5b Opening 3 1st gas flow path 4 1st gas supply port 5 Burner outer pipe 6 2nd gas flow path 7 2nd gas supply port 8 Spark plug 9 Electrode 10 Earth electrode 11 Porous body 12a, 12b, 14 Flange 13 Mounting screw 15 Combustion mode switching device 16 Control device 17 Combustion air source 18 First fuel gas source 19 Second fuel gas source 20a-20f On-off valve 21 Reformer 22 Fuel cell body 23 Raw Fuel Supply Source 24 Steam Supply Source 25 Catalyst 26 Hot Air Guide Tube 27 Carbon Monoxide Transformer / Remover 28 Air Supply Source

Claims (7)

Burner inner pipe having one end with a bottom and the other end opened to form a first gas flow passage inside; a burner outer pipe disposed outside the burner inner pipe, on the same side as the burner inner pipe Burner outer tube whose end is bottomed and the other end is opened at a position close to the opening of the burner inner tube and forms a second gas flow path between the burner inner tube; in the burner near the bottom of the burner inner tube 1st gas supply port opened to the 1st gas flow path in a pipe; 2nd gas supply port opened to the 2nd gas flow path in a burner outer pipe near the bottom part of a burner outer pipe; Opening of a burner inner pipe and a burner outer pipe A two-mode combustion burner comprising ignition means arranged at the side tip. The two-mode combustion burner according to claim 1, wherein the opening of the burner inner pipe is divided into a plurality of openings, and the plurality of openings are arranged in an island shape in the opening of the burner outer pipe. The two-mode combustion burner according to claim 1 or 2, wherein the opening of the burner inner tube and the burner outer tube is opened to the outside through a porous body having pores communicating front and back sufficient for gas to pass therethrough. The porous body is a porous ceramic, an aggregate of ceramic fibers, a sintered body of metal fibers, a heat-resistant metal fiber knitted fabric, or a laminate of a heat-resistant metal fiber knitted fabric and a metal porous plate. Item 4. The two-mode combustion burner according to item 3. Further, a premixed combustion mode for supplying a mixed gas of the first fuel gas and combustion air to one or both of the first gas supply port and the second gas supply port, and the first gas supply port or the second gas. 5. The combustion mode switching device according to claim 1, further comprising a combustion mode switching device that switches between a premixed combustion mode in which combustion air is supplied to one of the supply ports and a second fuel gas is supplied to the other. Mode burning burner. The two-mode combustion burner according to claim 5, wherein the first fuel gas is a raw fuel gas of the fuel cell, and the second fuel gas is an off-gas or reformed gas from the fuel cell. A fuel cell comprising the two-mode combustion burner according to claim 1.

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