JP4764699B2 - Combustion device for hydrogen supply device for fuel cell - Google Patents

Description

  The present invention relates to a combustion apparatus that heats a reformer that generates reformed gas mainly composed of hydrogen to be supplied to a fuel cell.

  A fuel cell is a device that directly generates electricity by electrochemically reacting hydrogen with oxygen in the air, and since it generates little NOx and CO2, it has attracted attention as an energy source with a very low environmental load. ing.

  In addition, there are several types of fuel cells depending on the electrolyte used. Among them, solid polymer fuel cells are particularly small, have low operating temperature, and have low noise. Technology.

  By the way, various fuels such as natural gas, gasoline, kerosene, etc. have been studied as raw fuels (hydrogen raw materials) such as hydrocarbons that make hydrogen, that is, fuel cells. Expectation is gathered for kerosene that is equipped.

  FIG. 4 is a diagram showing a system in which kerosene is used as a raw material for hydrogen used in a fuel cell. Desulfurization section A, reforming that causes reforming reaction to generate reformed gas mainly composed of hydrogen The apparatus B, the shift reaction unit C, and the CO selective oxidation unit D are configured to obtain a reformed gas containing high-purity hydrogen as a main component and supply it to the hydrogen electrode of the fuel cell.

  The reformer is configured to have a vaporizer that vaporizes the hydrogen raw material and a catalyst layer that reforms the hydrogen raw material vaporized by the vaporizer. When kerosene is used as the hydrogen raw material, Requires an operating temperature of approximately 800 ° C. Therefore, a combustion device for heating the reformer for the purpose of maintaining the operating temperature at the start-up of the fuel cell and during the power generation operation is essential.

  This combustion device raises the temperature of the reformer by burning fuel such as kerosene at the start of the fuel cell, and burns the hydrogen electrode exhaust gas discharged from the hydrogen electrode of the fuel cell as the fuel during power generation operation, It has a function of maintaining the reformer at a predetermined temperature.

  Here, a combustion apparatus using kerosene as fuel will be described with reference to FIGS.

  First, FIG. 5 is a schematic diagram of a fuel cell system. As shown in FIG. 5, this fuel cell system is a fuel cell 1 having a hydrogen electrode and an air electrode. A reformer 2 for generating a reformed gas of components, a combustion device 3 for heating the reformer 2, a kerosene supply passage 4 for supplying kerosene to the combustion device 3, and combustion air to the combustion device 3 A supply passage 6 for supplying kerosene as a hydrogen raw material to the reformer 2, and a hydrogen-based reformed gas generated by the reformer 2 at the hydrogen electrode of the fuel cell. Hydrogen gas supply passage 7 for supplying, exhaust gas supply passage 8 for supplying hydrogen electrode exhaust gas containing unreacted hydrogen and discharged from the hydrogen electrode to the combustion device 3, and supplying air to the air electrode of the fuel cell Air supply passage 9, air electrode exhaust discharged from air electrode Scan has an exhaust gas passage 10 to pass. In FIG. 5, the desulfurization part A, the shift reaction part C, and the CO selective oxidation part D are not shown.

  FIG. 6 is a structural diagram of the combustion apparatus 3. In the casing 41, a vaporizer 42 that vaporizes kerosene as a fuel to form a combustion gas, and the combustion gas produced by the vaporizer 42 and the primary gas are shown. When the mixed gas burner 43 that burns the mixed gas for combustion mixed with air, the exhaust gas burner 44 that burns the exhaust gas generated at the hydrogen electrode of the fuel cell 1, and the gas ejected from the mixed gas burner 43 and the exhaust gas burner 44 burn The secondary air passage portion 46 having a secondary air supply portion 45 for supplying secondary air to the flame of the air and the air pressure-fed from an air pressure feeding portion (not shown) to an air supply chamber 47 provided in the housing 41 Is provided.

  The mixed gas burner 43 is fitted with a mixing portion 49 made of a cylindrical member that mixes a combustion gas obtained by vaporizing liquid fuel and primary air at a lower portion of a cylindrical burner main body 48 disposed in the housing 41. The inner hole of the burner main body 48 is configured as a mixed gas feed unit 50 that feeds the combustion mixed gas sent from the mixing unit 49.

  The exhaust gas burner 44 includes an exhaust gas supply pipe 51 that includes an exhaust gas supply pipe 51 that communicates with the exhaust gas supply section 8 that extends from the hydrogen electrode, and an outer space of the burner body 48 that communicates with the upper end of the exhaust gas supply pipe 51. Further, an ignition device 53 for igniting the mixed gas is inserted into the exhaust gas feed section 52, and the ignition device 53 is disposed so as to face the mixed gas burner 43.

  A flame plate 54 is placed on the burner body 48, and a plurality of flame holes 55 through which mixed gas and exhaust gas are ejected are provided at predetermined positions of the flame plate 54. The surface of the flame plate 54 is flame. The combustion space 56 is formed.

  By configuring in this way, the combustion device 3 can be reduced in size, and the flame can be easily transferred from the mixed gas burner 43 to the exhaust gas burner 44 to maintain a good combustion state.

JP-A-2005-214543

  However, in the conventionally proposed combustion apparatus, since the exhaust gas feed section through which the exhaust gas passes is composed of a combination of a plurality of parts, a gap is easily generated between these parts, and the exhaust gas may leak out from this gap. was there.

  The ignition device is mounted so as to pass through the exhaust gas feed section and face the mixed gas burner. However, it is very difficult to mount the ignition device in an airtight manner, and the same applies to the gap generated in the ignition device insertion portion. The exhaust gas leaked out.

  However, even if the exhaust gas leaks from these gaps, if it leaks into the combustion space where the flame is formed, it can be said that there is no particular problem because it is caught in the flame formed by the exhaust gas burner and burned. . On the other hand, if the exhaust gas leaks into the air supply chamber, the exhaust gas mixes with the air supplied from the air passage in the air supply chamber, and then passes through the mixing section and is ejected into the combustion space. It passes through the secondary air passage and is ejected from the secondary air supply section into the combustion space. However, since the exhaust gas leaking into the air supply chamber is diluted many times as much as the theoretical air in the air supply chamber, it cannot be burned unless it is supplied very close to the flame.

  When the supply of exhaust gas from the fuel cell is started and the combustion in the exhaust gas burner is stabilized, the supply of fuel gas to the carburetor is stopped and no flame is present in the mixed gas burner, so the supply chamber The exhaust gas contained in the air that has passed through the mixing section cannot burn. Of course, since there is no flame in the secondary air supply section, the exhaust gas contained in the air that has passed through the secondary air passage cannot be combusted. That is, there has been a problem that the exhaust gas leaking into the air supply chamber is discharged without passing through the combustion space without being burned in any case.

  Therefore, in order to prevent such discharge of unburned exhaust gas, it is necessary to completely seal, for example, by welding all the joints of the parts through which the exhaust gas passes, which increases the manufacturing cost. It was.

  An object of the present invention is to provide a combustion apparatus for a hydrogen supply apparatus for a fuel cell that prevents the exhaust gas from being discharged unburned without increasing the manufacturing cost. And

A mixing chamber that mixes combustion gas vaporized with liquid fuel and primary air to form a mixed gas for combustion, an exhaust gas chamber that is attached to the outer periphery of the mixing chamber and contains exhaust gas from the fuel cell, and an exhaust gas chamber An exhaust gas supply pipe for supplying exhaust gas from the fuel cell, an air chamber for storing secondary air supplied to the flame, a flame plate connecting the mixing chamber, the exhaust gas chamber and the air chamber, and this flame plate A plurality of jetting holes penetrating through and an ignition device for igniting the mixed gas, wherein the jetting hole forms a mixed gas deriving portion for deriving a mixed gas for combustion at the center of the flame plate, and surrounds the mixed gas deriving portion; An exhaust gas deriving unit for deriving exhaust gas in a state where the exhaust gas is derived, and a secondary air deriving unit for deriving secondary air in a state of surrounding the exhaust gas deriving unit, and the ignition device passing through the air chamber Penetrate the flame plate It relates to a combustion apparatus for a fuel cell the hydrogen supply device according to claim is provided to face the serial mixed gas outlet portion.

  By configuring as described above, it is possible to effectively prevent the exhaust gas discharged from the fuel cell from leaking without taking the trouble of sealing the joint portion of the parts, so that safety and manufacturing costs can be reduced. A suppressed device can be manufactured. Further, even if the exhaust gas leaks into the housing, the exhaust gas is mixed into the secondary air and supplied to the flame for combustion, so that it is not discharged unburned.

  The preferred embodiment of the present invention will be briefly described by showing the operation of the present invention.

  The present invention relates to a combustion apparatus for heating a reformer of a hydrogen supply apparatus, wherein a combustion mixed gas obtained by mixing a combustion gas and primary air and an exhaust gas generated at a hydrogen electrode of a fuel cell are provided on a flame plate. It is made to erupt from the jetted hole and burn.

  As a specific configuration, an exhaust gas chamber for storing exhaust gas is attached to the outer periphery of a mixing chamber for mixing combustion gas and primary air, and an exhaust gas supply pipe for supplying exhaust gas from the fuel cell is connected to the exhaust gas chamber. The exhaust gas discharged from the fuel cell when the fuel cell is started is sent from the exhaust gas supply pipe to the exhaust gas chamber.

  The exhaust gas chamber is formed by a cup-shaped member having an upper surface opened and has a hole in the bottom surface. The opening on the upper surface is connected to a flame plate having an ejection hole, and the mixing chamber is passed through the hole in the bottom surface. It is designed to be attached. Therefore, the exhaust gas chamber can be kept airtight if the top opening and bottom hole are welded and sealed to the flame plate and the mixing chamber, respectively, and the exhaust gas leaks into the air chamber with a simpler structure than before. Can be prevented.

  Also, even if the exhaust gas leaks into the air chamber, the exhaust gas is mixed with air in the air chamber and then ejected from the flame plate, supplied as secondary air to the flame and burned. The exhaust gas is not exhausted.

  Specific embodiments of the present invention will be described with reference to the drawings.

  The hydrogen supply apparatus according to the present embodiment includes a reformer 2 that heats a raw fuel (hydrogen raw material) such as a hydrocarbon to generate a reformed gas containing hydrogen as a main component, and a combustion apparatus 3 that heats the reformer 2. The reformed gas mainly composed of hydrogen generated in the reformer 2 is configured to be supplied to the fuel cell 1 having a hydrogen electrode and an air electrode.

  Specifically, the reformer 2 has an existing structure having a vaporizer 11 for vaporizing a hydrogen raw material and a catalyst layer for reforming the hydrogen raw material vaporized by the vaporizer 11.

  Further, as shown in FIG. 1, the combustion apparatus 3 includes a carburetor 11 that vaporizes kerosene as a fuel into a combustion gas in a cylindrical casing 14 disposed at a lower portion of the reformer 2. The mixed gas burner 26 for burning the mixed gas for combustion in which the combustion gas produced by the vaporizer 11 and the primary air are mixed, the exhaust gas burner 27 for burning the exhaust gas generated at the hydrogen electrode of the fuel cell 1, and the combustion gas Primary air to be mixed with the air chamber 15 containing secondary air to be supplied to the flame when the gas jetted from the mixed gas burner 26 and the exhaust gas burner 27 burns, and a pneumatic feeding section (not shown) to the air chamber 15 A blower passage 5 is provided for supplying air fed from the air.

  Hereinafter, the combustion apparatus 3 according to the present embodiment will be described in detail.

  The vaporizer 11 includes a kerosene supply passage 4 for supplying kerosene to the vaporizer 11, a heater 16 for raising the temperature of the vaporizer 11, and the heater in a box-shaped main body 11 a disposed below the housing 14. And a nozzle 17 that ejects the combustion gas that has been heated and vaporized in the vaporizer 11 by the nozzle 16, and the combustion gas is injected from the nozzle 17 into the mixing chamber 12 of the mixed gas burner 26 described later. It is configured.

  The mixed gas burner 26 is formed by disposing a cylindrical mixing chamber 12 in the approximate center of the housing 14 to mix the combustion gas vaporized by the vaporizer 11 and the primary air into a combustion mixed gas. Yes.

  The exhaust gas burner 27 has a structure having an exhaust gas supply pipe 13 that communicates with the exhaust gas supply section 8 that extends from the hydrogen electrode of the fuel cell 1, and an exhaust gas chamber 19 that communicates with the downstream end of the exhaust gas supply pipe 13. The exhaust gas discharged from the hydrogen electrode of the fuel cell 1 is supplied to the exhaust gas chamber 19 through the exhaust gas supply pipe 13.

  The exhaust gas chamber 19 is formed of a bottomed cup-shaped member having an open upper surface, and further, a hole is provided in the bottom surface of the cup-shaped member, so that the mixing chamber 12 can be inserted by inserting the mixing chamber 12 into the hole. 12 is attached to the outer periphery. Therefore, the exhaust gas chamber 19 can be kept airtight by sealing the opening on the upper surface to the flame plate 23 described later and the hole on the bottom surface to the mixing chamber 12, and the exhaust gas leaks with a simple configuration. Can be prevented.

  The mixing chamber 12, the exhaust gas chamber 19 and the air chamber 15 are connected to a flame plate 23 provided with a plurality of through holes 23a, 23b and 23c as shown in FIG. The housing 14 is in a closed state.

  Of the ejection holes 23a, 23b, and 23c provided in the flame plate 23, the ejection hole 23a provided in the central portion of the flame plate 23 communicates with the mixing chamber 12, and is a mixed gas for deriving a combustion mixed gas. The derivation unit 20 is configured, and the combustion mixed gas ejected from the mixed gas derivation unit 20 is ignited by the ignition device 25 and starts combustion.

  The ignition device 25 is inserted into the air chamber 15, and is provided so as to penetrate the flame plate 23 and the tip thereof faces the mixed gas outlet 20.

  Further, a net member 24 is disposed in the ejection hole 23a, and is configured to prevent backfire of the flame when the combustion mixed gas ejected from the mixed gas outlet 20 is combusted. Therefore, it is excellent in safety, and since the diameter of the ejection hole 23a can be formed large, the formation thereof becomes extremely simple and the manufacturing cost can be reduced.

  And the ejection hole 23b is provided so that the circumference | surroundings of the center ejection hole 23a may be surrounded, This ejection hole 23b is connected with the exhaust gas chamber 19, and is comprised as the exhaust gas derivation | leading-out part 21 which derives | emits exhaust gas.

  Further, an ejection hole 23c is provided at the peripheral edge of the flame plate 23 so as to surround the circumference of the ejection hole 23b, and the ejection hole 23c communicates with the air chamber 15 to derive secondary air. The air outlet 22 is configured. Therefore, the air that has flowed into the air chamber 15 from the blower passage 5 is ejected from the secondary air outlet 22 and supplied as secondary air to the flame formed by the mixed gas burner 26 and the exhaust gas burner 27.

  By providing the secondary air lead-out part 22 in this way, there is a gap in the connecting portion between the exhaust gas chamber 19 and the flame plate 23 and the mixing chamber 12, and the exhaust gas leaks into the air chamber 15 from here and the secondary air Even if it is mixed, the secondary air is supplied in the vicinity of the exhaust gas deriving section 21, so that the exhaust gas contained in the secondary air is reliably burned by the exhaust gas burner 27, and the exhaust gas remains unburned. Prevent it from being discharged.

  In FIG. 1, the mixed gas deriving unit 20, the exhaust gas deriving unit 21, and the secondary air deriving unit 22 are arranged on a flat flame plate 23, and the mixed gas, the exhaust gas, and the secondary air are disposed from the same surface. Although it is configured to eject, the shape of the flame plate 23 may be changed so that the secondary air deriving unit 22 is positioned upstream of the exhaust gas deriving unit 21 (and the mixed gas deriving unit 20). Good. In short, since the secondary air is supplied to the flame, it is sufficient that the flame is present at the point where the secondary air is ejected.

  Moreover, the number of the ejection holes 23a, 23b, and 23c and the size of the holes can be designed as appropriate, and are not limited to the examples.

  The downstream end of the housing 14 is bent inward to form a secondary air restricting portion 28, and the secondary air ejected from the secondary air outlet portion 22 is centered along the secondary air restricting portion 28. The flow is regulated so that it is approached and goes to the flame. Therefore, secondary air can be reliably supplied to the flame, and when the exhaust gas leaks out and enters the secondary air, it is effective to burn the exhaust gas and discharge it unburned. To prevent.

  Next, operation | movement of the combustion apparatus 3 in the above-mentioned structure is demonstrated.

  First, when the operation of the fuel cell 1 is instructed, energization of the heater 16 is started and the vaporizer 11 is heated. When the temperature of the vaporizer 11 reaches a temperature at which kerosene can be vaporized, an instruction to start supplying kerosene is issued to the vaporizer 11, and the kerosene is supplied to the vaporizer 11 through the kerosene supply passage 4. .

  The kerosene supplied to the vaporizer 11 becomes heated and vaporized combustion gas, and this combustion gas is ejected from the nozzle 17, and the combustion gas ejected from the nozzle 17 enters the mixing chamber 12. At this time, since the air in the air chamber 15 is also drawn into the mixing chamber 12 as primary air, the combustion gas and the primary air are mixed in the mixing chamber 12 to become a combustion mixed gas.

  The combustion gas mixture is ejected from the gas mixture outlet 20 provided at the center of the flame plate 23 and ignited by the ignition device 25 to start combustion in the gas mixture burner 26.

  At this time, the secondary air is ejected from the secondary air outlet 22 and supplied to the flame formed by the combustion of the combustion gas mixture, so that the combustion gas mixture is completely combusted.

  Thus, the reformer 2 is heated by burning the mixed gas for combustion. When the temperature of the reforming device 2 rises to the operating temperature, the reforming device 2 starts generating reformed gas containing hydrogen as a main component from kerosene as raw fuel such as hydrocarbons. The reformed gas is supplied to the hydrogen electrode of the fuel cell 1 through the hydrogen gas supply passage 7 to operate the fuel cell 1, and the fuel cell 1 performs the power generation operation by reacting the reformed gas mainly composed of hydrogen with oxygen. Is called.

  During the power generation operation of the fuel cell 1, not all of the hydrogen-based reformed gas supplied to the hydrogen electrode of the fuel cell 1 is consumed for power generation. The exhaust gas is discharged as it is contained, and this exhaust gas is also used for combustion in the combustion device 3.

  Specifically, the exhaust gas is supplied from the exhaust gas supply passage 8 through the exhaust gas supply pipe 13 to the exhaust gas chamber 19 and ejected from the exhaust gas outlet 21. Then, it comes into contact with the flame already formed in the mixed gas outlet 20 and ignites and burns, and combustion by both the mixed gas for combustion and the exhaust gas is started.

  The flames of both the mixed gas for combustion and the exhaust gas are completely burned by taking in the secondary air supplied from the secondary air deriving unit 22, and the heating of the reformer 2 is continued.

  Thereafter, the supply of kerosene to the vaporizer 11 is stopped when the combustion of the exhaust gas is stabilized, the combustion is shifted to the exhaust gas alone, and the heating of the reformer 2 is continued.

  Even if the exhaust gas leaks into the air chamber 15 from the gap during the exhaust gas combustion alone, the exhaust gas mixes with the air in the air chamber 15 and is ejected from the secondary air outlet 22 together with the secondary air. Therefore, the exhaust gas contained in the secondary air burns with the flame and is prevented from being discharged unburned.

  Next, another embodiment of the present invention will be described with reference to FIG.

  In FIG. 3, an exhaust gas chamber 19 is provided on the outer periphery of the mixing chamber 12, and a part of the exhaust gas chamber 19 is formed so as to project to the air chamber 15, and an exhaust gas supply pipe 13 is formed on the bottom surface of the projecting portion. It is connected.

  By connecting the exhaust gas supply pipe 13 to the bottom surface of the exhaust gas chamber 19 in this way, the exhaust gas burner 27 can be configured more easily.

It is front sectional drawing which shows a present Example. It is a top view which shows the flame plate of a present Example. It is a figure which shows the principal part of the other Example. This is a system for producing hydrogen used in a fuel cell. 1 is a schematic view of a fuel cell system. It is a front sectional view showing a conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Mixing chamber 13 Exhaust gas supply pipe 15 Air chamber 19 Exhaust gas chamber 20 Mixed gas derivation part 21 Exhaust gas derivation part 22 Secondary air derivation part 23 Flame 23a, 23b, 23c Ejection hole 25 Ignition device 28 Secondary air throttling part

Claims (1)

A mixing chamber that mixes combustion gas vaporized with liquid fuel and primary air to form a mixed gas for combustion, an exhaust gas chamber that is attached to the outer periphery of the mixing chamber and contains exhaust gas from the fuel cell, and an exhaust gas chamber An exhaust gas supply pipe for supplying exhaust gas from the fuel cell, an air chamber for storing secondary air supplied to the flame, a flame plate connecting the mixing chamber, the exhaust gas chamber and the air chamber, and this flame plate A plurality of jetting holes penetrating through and an ignition device for igniting the mixed gas, wherein the jetting hole forms a mixed gas deriving portion for deriving a mixed gas for combustion at the center of the flame plate, and surrounds the mixed gas deriving portion; An exhaust gas deriving unit for deriving exhaust gas in a state where the exhaust gas is derived, and a secondary air deriving unit for deriving secondary air in a state of surrounding the exhaust gas deriving unit, and the ignition device passing through the air chamber Penetrate the flame plate Combustion apparatus for a fuel cell the hydrogen supply device, characterized in that is provided so as to face the serial mixed gas outlet portion.

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