JP5135123B2 - Combustion equipment - Google Patents

Description

  The present invention relates to a combustion apparatus that burns two types of fuel, such as kerosene and other liquid fuels, and a gas containing hydrogen, and in particular, a reforming unit for generating a reformed gas mainly containing hydrogen to be supplied to a fuel cell. It is used for heating the device.

  A hydrogen supply device for supplying hydrogen to a fuel cell includes a reformer that generates a reformed gas mainly composed of hydrogen from a hydrogen raw material by a reforming reaction, and a combustion device that heats the reformer. When kerosene is used as a raw material, the reformer needs an operating temperature of about 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 indispensable.

  This combustion device raises the temperature of the reforming device by burning a mixed gas obtained by mixing the vaporized gas obtained by vaporizing kerosene with primary air when the fuel cell is started, and exhaust gas discharged from the hydrogen electrode of the fuel cell during power generation operation. And a hydrogen-containing gas such as hydrogen gas generated by the reformer is burned as fuel, thereby maintaining the reformer at a predetermined temperature.

  In other words, this combustion apparatus is required to be able to burn two types of fuel, a mixed gas and a hydrogen-containing gas, and at the same time, shortening the ignition time that directly affects the fuel cell start-up time, and NOx / CO2 emission There is a demand for reducing the environmental burden by reducing the amount, as well as a high level of safety and durability that is small and inexpensive.

  Therefore, conventionally, a combustion apparatus that combusts a mixed gas and a hydrogen-containing gas on the same surface has been proposed (Patent Document 1), thereby enabling the apparatus to be miniaturized. Here, a conventional combustion apparatus will be described with reference to FIG.

  FIG. 6 is a cross-sectional view of the combustion apparatus, which includes a heater 30 and a vaporizer 31 that heats and vaporizes liquid fuel, and a mixing tube that mixes the vaporized gas vaporized by the vaporizer 31 and combustion air to form a mixed gas. 32, a mixed gas burner 33 for burning the mixed gas mixed in the mixing pipe 32, a hydrogen-containing gas to which hydrogen-containing gas such as exhaust gas discharged from the hydrogen electrode of the fuel cell or hydrogen gas generated by the reformer is supplied A supply pipe 34 and a hydrogen-containing gas burner 35 for burning the hydrogen-containing gas are configured.

  The flame plate 36 in which a flame is formed by combustion of these burners is provided with a mixed gas ejection hole 37 through which a mixed gas is ejected at the center, and a hydrogen-containing gas is ejected around the mixed gas ejection hole 37. A hydrogen-containing gas ejection hole 38 is provided.

  Further, an ignition device 39 for igniting the first combustion gas is attached to the flame plate 36, and a secondary air ejection hole 40 for supplying secondary air to the flame on the downstream outer periphery of the flame plate 36. Is provided.

  Next, the operation of the combustion apparatus configured as described above will be described.

  First, when the operation of the fuel cell is instructed, the heater 30 starts heating the vaporizer 31, and when the vaporizer 31 is heated to a temperature at which kerosene can be vaporized, liquid fuel is supplied to the vaporizer 31. Is done. The liquid fuel heated and vaporized by the vaporizer 31 becomes a vaporized gas, and the vaporized gas and the primary air are mixed in the mixing pipe 32 to become a mixed gas. Then, the mixed gas is ejected from a mixed gas ejection hole 37 provided in the center portion of the flame plate 36, and is ignited by the ignition device 39 to start combustion.

  At that time, the secondary air is ejected from the secondary air ejection hole 40 to the flame, and the secondary air is supplied to the flame formed by the combustion of the mixed gas, so that the mixed gas is completely combusted. .

  Thus, the reformer is heated by the combustion of the mixed gas. Then, when the temperature of the reformer rises to the operating temperature, generation of hydrogen-based reformed gas is started, the hydrogen-based reformed gas is supplied to the fuel cell, the fuel cell is activated, and power generation operation is started. Is done.

  During the power generation operation of the fuel cell, not all of the hydrogen-based reformed gas supplied to the fuel cell is consumed for power generation, but is discharged as exhaust gas while containing unreacted hydrogen gas of about several tens of percent. Therefore, the exhaust gas containing hydrogen is supplied to the combustion apparatus, and is ejected from the hydrogen-containing gas ejection hole 38 through the hydrogen-containing gas supply pipe 34.

  The hydrogen-containing gas ejected from the hydrogen-containing gas ejection hole 38 is ignited and combusted by contact with the flame formed in the mixed gas ejection hole 37, and combustion by both the mixed gas and the hydrogen-containing gas is started. . Both flames are combusted by taking in the secondary air supplied from the secondary air ejection holes 40 and heat the reformer.

  Thereafter, when the reforming apparatus is operated to generate reformed gas containing hydrogen as a main component, the supply of liquid fuel to the vaporizer 31 is stopped and a part of the reformed gas is also supplied with the hydrogen-containing gas supply pipe 34. Is switched to combustion with a hydrogen-containing gas alone. In the single combustion of the hydrogen-containing gas, only air that does not contain liquid fuel is ejected from the mixed gas ejection hole 37, and the hydrogen-containing gas is obtained by taking in this air and the secondary air supplied from the secondary air ejection hole 40. It burns and the reformer is heated.

JP 2005-214543 A

  By the way, since the amount of exhaust gas discharged from the fuel cell depends on the output of the fuel cell, when the hydrogen-containing gas is burned alone, if the output of the fuel cell is low and the amount of exhaust gas discharged is small, the amount of combustion is insufficient. In some cases, the temperature required for the operation of the reformer cannot be maintained. In such a case, the liquid fuel is again supplied to the vaporizer to generate a mixed gas, and the operation is controlled to heat the reformer by burning both the mixed gas and the hydrogen-containing gas. Become.

  At this time, if the vaporizer is heated by energizing the heater after receiving the combustion request for the mixed gas, it takes time until the mixed gas is generated, and the temperature of the reformer can be maintained. It will disappear. Therefore, in order to be able to respond immediately to the combustion demand, the carburetor must always be maintained at a temperature at which liquid fuel can be vaporized. However, even when the hydrogen-containing gas is not combusted without using the carburetor, it is necessary to energize the heater and continue to heat the carburetor, so that useless power is consumed.

  The present invention is for solving the above-described problems, and provides a combustion apparatus that can prevent wasteful power consumption by suppressing energization of a heater that heats a vaporizer and efficiently vaporize liquid fuel. The purpose is to do.

  The present invention relates to a first liquid fuel vaporization unit that vaporizes liquid fuel, a first liquid fuel supply pipe that supplies fuel to the first liquid fuel vaporization unit, a fuel gas vaporized in the first liquid fuel vaporization unit, and a combustion gas A first mixing unit that mixes air, a mixed gas ejection hole from which a mixed gas mixed in the first mixing unit ejects, a hydrogen-containing gas supply pipe that supplies a hydrogen-containing gas, and a hydrogen that ejects a hydrogen-containing gas In a combustion apparatus having a containing gas ejection hole and a flame plate in which a mixed gas ejection hole is provided at a central portion and a hydrogen containing gas ejection hole is provided so as to surround the mixed gas ejection hole. A second liquid fuel vaporization section that recovers and heats the heat of the flame formed, a second liquid fuel supply pipe that supplies liquid fuel to the second liquid fuel vaporization section, a hydrogen-containing gas, and a second liquid fuel vaporization 2nd mixing which mixes with vaporized gas vaporized in part The provided second mixing section is a combustion device, characterized in that communication with the hydrogen-containing gas ejection hole.

  2. The combustion apparatus according to claim 1, wherein the hydrogen-containing gas supply pipe is provided so that a tip thereof faces the second liquid fuel vaporization section.

  3. The combustion apparatus according to claim 1, wherein a part of a peripheral wall forming the second liquid fuel vaporizing portion is in contact with the flame.

  The second liquid fuel supply pipe opens to the hydrogen-containing gas supply pipe, and the liquid fuel flowing out from the second liquid fuel supply pipe is supplied to the second liquid fuel vaporization section through the hydrogen gas supply pipe. A combustion apparatus according to any one of claims 1 to 3.

  By comprising as mentioned above, when combustion of mixed gas is needed at the time of hydrogen-containing gas independent operation, vaporized gas can be generated by supplying liquid fuel to the 2nd liquid fuel vaporization part. . Therefore, since it is not necessary to energize the heater and heat the first liquid fuel vaporization section after shifting to the hydrogen-containing gas single operation, it is possible to suppress power consumption.

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

  The present invention is, for example, a combustion apparatus for heating a reformer for generating a reformed gas containing hydrogen as a main component supplied to a fuel cell, in which mixed gas is ejected from a mixed gas ejection hole and mixed. After the gas is combusted, the hydrogen-containing gas is ejected from the hydrogen-containing gas ejection hole to combust the hydrogen-containing gas.

  Specifically, when the fuel cell is started, a mixed gas obtained by mixing vaporized gas obtained by heating and vaporizing liquid fuel such as kerosene and primary air is ejected from a mixed gas ejection hole provided in the center portion of the flame plate. A flame is formed. When the reformer is heated by the combustion of the mixed gas and the reformed gas containing hydrogen as a main component is generated by the reformer, the operation of the fuel cell is started.

  When the fuel cell starts operation, the exhaust gas containing hydrogen discharged from the fuel cell is ejected from the hydrogen-containing gas ejection hole. The hydrogen-containing gas ejection holes are provided so as to surround the mixed gas ejection holes, and the hydrogen-containing gas burns in contact with the flame of the combustion mixed gas.

  Thereafter, when the combustion with the hydrogen-containing gas is stabilized, the supply of the liquid fuel is stopped and the combustion with only the hydrogen-containing gas is performed. If it is low and the amount of exhaust gas discharged is small, the amount of combustion is insufficient and the temperature of the reformer cannot be maintained. In such a case, the reformer is heated by supplying liquid fuel from the second liquid fuel supply pipe to the second liquid fuel vaporization section to generate a mixed gas and burning both the mixed gas and the exhaust gas. The operation is controlled.

  In addition, since the 2nd liquid fuel vaporization part collect | recovers the heat of a flame and becomes high temperature, the 2nd liquid fuel vaporization part can vaporize the supplied liquid fuel immediately.

  Therefore, when there is a demand for combustion with the mixed gas for combustion, it is possible to respond immediately, and after shifting to single combustion of hydrogen-containing gas, heating of the heater is not required to vaporize the liquid fuel. This will reduce power consumption.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

Example 1
FIG. 1 is a front cross-sectional view of a combustion apparatus according to a first embodiment. A first liquid fuel vaporizing section 2 that vaporizes kerosene as fuel to vaporize gas in a cylindrical casing 1 and the first liquid. A mixed gas burner 3 that burns a mixed gas obtained by mixing the vaporized gas produced by the fuel vaporizing unit 2 and primary air, and a gas containing hydrogen, such as an exhaust gas generated by a fuel cell or a hydrogen gas generated by a reformer, is burned. A hydrogen-containing gas burner 4, primary air mixed with combustion gas, mixed gas burner 3, and air chamber 5 for storing secondary air to be supplied to the flame when the gas ejected from hydrogen-containing gas burner 4 burns; air A blower passage 6 is provided for supplying air pumped from a pneumatic feed section (not shown) to the chamber 5.

  The first liquid fuel vaporization unit 2 includes a vaporization unit main body 2a, a first liquid fuel supply pipe 7 for supplying kerosene to the vaporization unit main body 2a, a heater 8 for raising the temperature of the first liquid fuel vaporization unit 2, A nozzle 9 for jetting combustion gas heated and vaporized in the first liquid fuel vaporization section 2 by the heater 8 is provided. From the nozzle 9 to the first mixing section 10 of the mixed gas burner 3 to be described later. It is comprised so that the gas for combustion may be injected.

  The mixed gas burner 3 is provided with a bent cylindrical first mixing portion 10 in the substantially center of the housing 1 to mix the vaporized gas vaporized by the first liquid fuel vaporizing portion 2 and the primary air into a mixed gas. Is formed.

  The hydrogen-containing gas burner 4 includes a hydrogen-containing gas supply unit 11 into which the exhaust gas discharged from the hydrogen electrode of the fuel cell and the hydrogen gas generated by the reformer flow, and a hydrogen-containing gas supply in communication with the hydrogen-containing gas supply unit 11. This structure has a pipe 12 and a second mixing portion 13 in which the downstream end of the hydrogen-containing gas supply pipe 12 is connected. The hydrogen-containing gas passes through the hydrogen-containing gas supply pipe 12 and is mixed into the second mixing section 13. Supplied to the unit 13.

  The second mixing unit 13 is connected to a second liquid fuel supply pipe 14 to which liquid fuel is supplied, and is provided with a second liquid fuel vaporization unit 15 facing the second liquid fuel supply pipe 14. The second liquid fuel vaporization section 15 includes a heat recovery means 16 that recovers the heat of the flame.

  The first mixing unit 10, the second mixing unit 13 and the air chamber 5 are connected to a flame plate 17 provided with a plurality of through-holes as shown in FIG. The body 1 is in a closed state.

  Among the ejection holes provided in the flame plate 17, the mixed gas ejection hole 18 provided in the central portion of the flame plate 17 communicates with the first mixing unit 10.

  Further, a mesh member 19 is disposed in the mixed gas ejection hole 18 so as to prevent backfire of the flame when the mixed gas burns. Therefore, it is excellent in safety, and the diameter of the mixed gas main ejection hole can be formed large, so that the formation is extremely simple and the manufacturing cost can be reduced.

  A small-diameter hydrogen-containing gas ejection hole 20 provided around the mixed gas ejection hole 18 communicates with the second mixing portion 13.

  Further, a secondary air ejection hole 21 is provided at the peripheral edge of the flame plate 17 so as to surround the periphery of the hydrogen-containing gas ejection hole 20, and the secondary air ejection hole 21 communicates with the air chamber 5. . Therefore, the air flowing into the air chamber 5 from the air passage 6 is supplied as secondary air to the flame formed by the mixed gas burner 3 and the hydrogen-containing gas burner 4 through the secondary air ejection holes 21.

  In addition, the number of each ejection hole and the magnitude | size of a hole can be designed suitably, and are not limited to an Example.

  Further, in the embodiment, the combustion apparatus is configured so that the flame is formed downward in the vertical direction, but may be configured so as to face upward.

  Next, the operation of the combustion apparatus according to this embodiment having the above-described configuration will be described.

  First, when the operation of the fuel cell is instructed, energization to the heater 8 is started to heat the first liquid fuel vaporization unit 2. When the temperature of the first liquid fuel vaporization unit 2 reaches a temperature at which kerosene can be vaporized, an instruction to start supplying kerosene to the first liquid fuel vaporization unit 2 is issued, and the kerosene is supplied to the first liquid fuel supply pipe. 7 is supplied to the first liquid fuel vaporization section 2.

  The kerosene supplied to the first liquid fuel vaporization unit 2 is heated to become vaporized gas, and this vaporized gas is ejected from the nozzle 9, and the vaporized gas ejected from the nozzle 9 flows into the first mixing unit 10. At this time, since the air in the air chamber 5 is also drawn into the first mixing unit 10 as primary air, the vaporized gas and the primary air are mixed into the mixed gas in the first mixing unit 10.

  The mixed gas is ejected from a mixed gas ejection hole 18 provided at the center of the flame plate 17 and ignited by an ignition device (not shown) to start combustion in the mixed gas burner 3.

  At this time, secondary air is ejected from the secondary air ejection holes 21 and supplied to the flame formed by the combustion of the mixed gas, so that the mixed gas is completely combusted.

  Thus, the reformer is heated by the combustion of the mixed gas. When the temperature of the reformer rises to the operating temperature, the reformer starts generating reformed gas mainly composed of hydrogen from kerosene as raw fuel such as hydrocarbons. This hydrogen-based reformed gas is supplied to the fuel cell, the fuel cell is activated, and a power generation operation is performed.

  During the power generation operation of the fuel cell, not all of the hydrogen-based reformed gas supplied to the fuel cell is consumed for power generation, but is discharged as exhaust gas while containing unreacted hydrogen gas of about several tens of percent. The exhaust gas is also used for combustion in the combustion device.

  Then, when the reformer is operated to generate a reformed gas containing hydrogen as a main component, the supply of kerosene to the first liquid fuel vaporization unit 2 is stopped and the process proceeds to combustion with the hydrogen-containing gas alone. However, immediately after the reformer operates, the amount of exhaust gas discharged from the fuel cell is unstable, and it is difficult to maintain stable combustion only with the exhaust gas discharged from the fuel cell. Immediately after the operation, a part of the reformed gas mainly composed of hydrogen generated in the reformer is also used for combustion in the hydrogen-containing gas burner 4.

  Specifically, the supply of kerosene to the first liquid fuel vaporization unit 2 is stopped, and a part of the reformed gas is supplied from the hydrogen-containing gas supply unit 11 to the second mixing unit 13 through the hydrogen-containing gas supply pipe 12. The gas is supplied and ejected from the hydrogen-containing gas ejection hole 20. At the same time, the exhaust gas from the fuel cell is also supplied from the hydrogen-containing gas supply unit 11 through the hydrogen-containing gas supply pipe 12 to the second mixing unit 13 and ejected from the hydrogen-containing gas ejection hole 20. In the contained gas burner 4, only the hydrogen-containing gas by the exhaust gas and the reformed gas is burned.

  Then, when the supply amount of the exhaust gas discharged from the fuel cell is stabilized, the supply of the reformed gas to the hydrogen-containing gas supply pipe 12 is stopped, and combustion with only the exhaust gas is performed.

  During this hydrogen-containing gas single combustion, only the air containing no combustion gas is ejected from the mixed gas ejection hole 18, and the combustion flame of the hydrogen-containing gas is supplied from this air and the secondary air ejection hole 21. The air is taken in and burned.

  Since the hydrogen-containing gas ejection holes 20 have a small hole diameter, the ejection speed of the hydrogen-containing gas ejected from here increases, and turbulent flow is generated in the hydrogen-containing gas after ejection. This turbulent flow promotes mixing of fuel and air, and the taken-in air can be used efficiently for combustion.

  By the way, at the time of this hydrogen-containing gas single combustion, if the output of the fuel cell is low and the amount of exhaust gas discharged is small, the amount of combustion becomes insufficient and the temperature of the reformer cannot be maintained. In such a case, the reformer is heated by supplying kerosene from the second liquid fuel supply pipe 14 to the second liquid fuel vaporization section 15 to generate a mixed gas and combusting both the mixed gas and the exhaust gas. The operation is controlled to

  During combustion, since the heat recovery means 16 recovers the heat of the flame formed by the hydrogen-containing gas burner 4, the second liquid fuel vaporization section 15 is maintained at a high temperature and is supplied from the second liquid fuel supply pipe 14. Liquid fuel can be vaporized immediately. That is, after the shift to the single combustion of the hydrogen-containing gas, heating by the heater 8 is not required to vaporize the liquid fuel, so that wasteful power consumption can be suppressed.

  The vaporized gas vaporized in the second liquid fuel vaporization unit 15 is mixed with the hydrogen-containing gas supplied from the hydrogen-containing gas supply pipe 12 in the second mixing unit 13 and ejected from the hydrogen-containing gas ejection hole 20. And burn.

(Example 2)
FIG. 3 is a sectional view of the combustion apparatus of the second embodiment.

  The second liquid fuel supply pipe 14 and the hydrogen-containing gas supply pipe 12 are both provided so that the tip faces the second liquid fuel vaporization section 15.

  With this configuration, kerosene supplied from the second liquid fuel supply pipe 14 is supplied from the hydrogen-containing gas supply pipe 12 when it is vaporized by the second liquid fuel vaporization section 15 to become vaporized gas. Since scavenging is performed by the hydrogen-containing gas, the vaporization of kerosene is promoted. Therefore, the combustion apparatus is excellent in vaporization efficiency.

(Example 3)
FIG. 4 is a cross-sectional view of the combustion apparatus of the third embodiment.

  The second liquid fuel vaporization unit 15 is provided downstream of the housing 1 and has a bottomed cylindrical shape including an inner peripheral wall 15a and an outer peripheral wall 15b. The internal space of the second liquid fuel vaporization unit 15 is The second mixing unit 13 is provided. A hydrogen-containing gas ejection hole 20 is provided in the inner peripheral wall 15a of the second liquid fuel vaporization section 15, and the inner peripheral wall 15a comes into contact with the flame of the hydrogen-containing gas burner 4 during combustion.

  That is, since the inner peripheral wall 15a of the second liquid fuel vaporization unit 15 serves as a heat recovery unit, it is not necessary to provide a separate heat recovery unit, and the second liquid fuel vaporization unit 15 can be efficiently heated. Furthermore, since the internal space of the second liquid fuel vaporization section 15 becomes the second mixing section 13, the structure is simplified and the assemblability is improved.

Example 4
FIG. 5 is a cross-sectional view of the combustion apparatus of the fourth embodiment.

  The second liquid fuel supply pipe 14 is joined to the hydrogen-containing gas supply pipe 12 inside the housing 1, and kerosene flowing through the second liquid fuel supply pipe 14 travels through the hydrogen-containing gas supply pipe 12. The second liquid fuel vaporization unit 15 is supplied.

  Since kerosene contains a carbon component, so-called coking occurs in which carbon is deposited when exposed to high temperatures. During combustion, the vicinity of the flame is very hot, and if the second liquid fuel supply pipe 14 is disposed in the vicinity of the flame, coking occurs at the tip, causing the second liquid fuel supply pipe 14 to be clogged. There is a risk that. Therefore, if the second liquid fuel supply pipe 14 is opened to the hydrogen-containing gas supply pipe 12 at a position away from the flame as in the embodiment, the hydrogen-containing gas is at a room temperature, so the second liquid fuel supply pipe 14 In addition to preventing the occurrence of coking, the structure is simplified and the assemblability is improved.

  When the second liquid fuel supply pipe 14 is joined to the hydrogen-containing gas supply pipe 12 in this way, it is desirable to configure the combustion device so that the flame is formed downward in the vertical direction as shown in the figure. By doing so, kerosene is reliably supplied to the second liquid fuel vaporization section 15 through the hydrogen-containing gas supply pipe 12 by gravity.

1 is a front sectional view showing Example 1. FIG. FIG. 3 is a plan view illustrating a main part according to the first embodiment. 5 is a front sectional view showing Example 2. FIG. 6 is a front sectional view showing Example 3. FIG. 6 is a front sectional view showing Example 4. FIG. It is a front sectional view showing a conventional example.

Explanation of symbols

2 First liquid fuel vaporization section 7 First liquid fuel supply pipe 10 First mixing section 12 Hydrogen-containing gas supply pipe 13 Second mixing section 14 Second liquid fuel supply pipe 15 Second liquid fuel vaporization section 17 Flame 18 Mixed gas Ejection hole 20 Hydrogen-containing gas ejection hole

Claims (4)

  Mixing a first liquid fuel vaporization section that vaporizes liquid fuel, a first liquid fuel supply pipe that supplies fuel to the first liquid fuel vaporization section, fuel gas vaporized in the first liquid fuel vaporization section, and combustion air A first gas mixing hole, a gas mixture injection hole from which the gas mixture mixed in the first mixing part is ejected, a hydrogen-containing gas supply pipe for supplying a hydrogen-containing gas, and a hydrogen-containing gas injection hole from which the hydrogen-containing gas is ejected A flame formed by a flame plate in a combustion apparatus having a mixed gas jet hole at the center and a flame plate provided with a hydrogen-containing gas jet hole so as to surround the mixed gas jet hole The second liquid fuel vaporization unit that recovers and heats the heat, the second liquid fuel supply pipe that supplies liquid fuel to the second liquid fuel vaporization unit, the hydrogen-containing gas and the second liquid fuel vaporization unit A second mixing section for mixing the vaporized gas Second mixing unit combustion apparatus, characterized in that communication with the hydrogen-containing gas ejection hole.   The combustion apparatus according to claim 1, wherein the hydrogen-containing gas supply pipe is provided so that a tip thereof faces the second liquid fuel vaporization section.   The combustion apparatus according to claim 1 or 2, wherein a part of the peripheral wall forming the second liquid fuel vaporizing portion is in contact with the flame.   The second liquid fuel supply pipe opens to the hydrogen-containing gas supply pipe, and the liquid fuel flowing out from the second liquid fuel supply pipe is supplied to the second liquid fuel vaporization section through the hydrogen gas supply pipe. The combustion apparatus according to any one of claims 1 to 3.

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