JP5525855B2 - Combustion device - Google Patents

Description

  The present invention relates to a combustion apparatus that burns two types of fuel, a first combustion gas and a second combustion gas, and more particularly, to a reforming apparatus for generating a reformed gas mainly composed of hydrogen to be supplied to a fuel cell. The present invention relates to a combustion apparatus used for heating.

  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. Gas fuel gas such as city gas, natural gas, and LPG, and liquid fuel such as kerosene are used as raw materials. For example, when kerosene is used as the hydrogen 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 during startup of the fuel cell and during power generation operation is indispensable.

  This combustion device raises the temperature of the reformer by burning a premixed gas (first combustion gas) in which fuel gas is mixed with primary air when the fuel cell is started, and from the hydrogen electrode of the fuel cell during power generation operation. It has a function of maintaining the reformer at a predetermined temperature by burning the discharged hydrogen-containing gas (second combustion gas) as fuel.

  In other words, the combustion device is required to be able to burn two types of fuel, the first combustion gas and the second combustion gas, and at the same time, shortening the ignition time that directly affects the fuel cell startup time, and NOx・ Reduction of environmental burden by reducing CO2 emissions, and further high level of safety and durability are required in a compact, inexpensive and safe manner.

  Therefore, a combustion apparatus has been proposed in which each of the first combustion gas and the second combustion gas is ejected from an ejection hole provided in the flame plate and burned on the same surface, thereby making it possible to reduce the size of the combustion apparatus. It became. (Patent Document 1)

  On the other hand, a combustion apparatus is also proposed in which the second combustion gas is jetted from the downstream of the first combustion gas at a right angle to the jet flow of the first combustion gas, thereby obtaining good combustion. It became so. (Patent Document 2)

JP-A-2005-214543 JP 2003-331882 A

  However, in the combustion apparatus of Patent Document 1, in order to improve the combustibility of the first combustion gas and reduce the air ratio and improve the thermal efficiency of the reformer, the ratio of primary air is made larger than the ratio of secondary air. There is a need. Under such conditions, for example, when the operation of the fuel cell is stable and combustion is performed with the second combustion gas, mixing with the secondary air supplied from the secondary air ejection section is good. Since the amount of secondary air is originally small, it is difficult to complete combustion, and mixing with the primary air ejected from the first combustion gas ejection section provided in the center of the flame plate is also difficult to promote. There has been a problem that the combustion gas cannot be burned completely.

  Further, in the combustion apparatus of Patent Document 2, since the gas chamber for ejecting the second combustion gas is provided downstream of the flame, the structure is complicated, and the gas chamber is exposed to the flame when the first combustion gas is burned. There is a risk of deformation and damage of the burner parts due to heat. Further, when the second combustion gas is burned under a condition where the proportion of primary air is larger than the proportion of secondary air, especially when the combustion amount is small and the injection speed of the second combustion gas is slow, the second combustion gas As a result, there is a problem that the second combustion gas cannot be completely burned.

  An object of the present invention is to solve the above-described problems, and an object of the present invention is to provide a combustion apparatus that can completely burn combustion gas, improves the thermal efficiency of the reformer, and has excellent durability.

The present invention relates to a combustion apparatus that burns a first combustion gas and then burns a second combustion gas, wherein the second combustion is performed so as to surround the first combustion gas ejection portion provided in the central portion. A flame plate provided with a combustion gas ejection portion, a second combustion gas chamber communicating with the second combustion gas ejection portion upstream of the flame plate, and ejection of the first combustion gas downstream of the flame plate The second combustion gas is ejected so as to form a swirling flow around the axis of the first combustion gas ejection direction at a substantially right angle to the direction, and the second combustion gas is ejected in the second combustion gas ejection direction . The present invention relates to a combustion apparatus comprising a second combustion gas swirl jetting means for jetting combustion gas.

  Further, the second combustion gas swirl jet means is a first swirl flow that is substantially perpendicular to the first combustion gas jet direction and has an axis in the first combustion gas jet direction as a center. The second combustion gas swirling means for ejecting the second combustion gas and the second combustion gas auxiliary ejection hole for ejecting the second combustion gas in the ejection direction of the first combustion gas. The combustion apparatus according to claim 1.

The second combustion gas swirling means includes a center of a minimum circle surrounding all the first combustion gas ejection holes provided in the first combustion gas ejection section, and a second combustion gas auxiliary ejection hole. a line connecting the centers, the combustion apparatus of claim 2 Symbol mounting, characterized in that for ejecting the second combustion gas between the second center of combustion gas assist injection holes adjacent to as the smallest circle line It is related.

Further, the second combustion gas swirling and jetting means is further provided with a small hole for jetting secondary air so as to surround the second combustion gas swirling means. This relates to the combustion apparatus described.

In addition, it is further provided with secondary air turning means for jetting secondary air in a direction substantially perpendicular to the jet direction of the first combustion gas downstream of the second combustion gas swirl jet means. The combustion apparatus according to claim 4.

  By configuring as described above, complete combustion of the combustion gas becomes possible, and the thermal efficiency of the reformer is improved, and at the same time, the combustion apparatus is excellent in durability.

It is a front sectional view regarding the combustion apparatus of the Example of this invention. It is the figure which showed the flame plate of the Example of this invention. It is the figure which showed the 2nd combustion gas swirl jet means of the Example of this invention. It is the figure which showed the state which combined the flame plate of the Example of this invention, and the 2nd combustion gas swirl jet means. It is the figure which showed the ejection state of the 2nd combustion gas of the Example of this invention.

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

  The present invention is a combustion apparatus for heating a reformer that generates reformed gas containing hydrogen as a main component supplied to a fuel cell, and includes a premixed gas (first combustion gas) from a first combustion gas ejection section. Gas) is ejected and burned, and then a hydrogen-containing gas (second combustion gas) is ejected from the second combustion gas ejection portion and combusted.

  Specifically, when the fuel cell is started, a first combustion gas, which is a mixture of fuel gas and primary air, is ejected from a first combustion gas ejection portion provided at the center of the flame plate, thereby forming a flame. The When the reformer is heated by the combustion of the first combustion gas and the reformed gas containing hydrogen as a main component is generated by the reformer, the fuel cell starts operation.

  When the fuel cell starts operation, the second combustion gas containing hydrogen discharged from the fuel cell is supplied from the hydrogen-containing gas chamber (second combustion gas chamber) upstream of the flame plate, and the second combustion gas is ejected. Erupts from the department. The second combustion gas ejection portion is provided so as to surround the first combustion gas ejection portion, and the second combustion gas is disposed in a direction substantially perpendicular to the ejection direction of the first combustion gas and for the first combustion gas. Since the second combustion gas swirl jetting means for jetting in a swirl flow around the axis of the gas ejection direction is provided, the second combustion gas becomes a swirl flow and becomes a flame of the first combustion gas. It is blown out and burns.

  Thereafter, when the operation of the fuel cell is stabilized, the combustion of the second combustion gas is mainly performed. At this time, primary air or lean first combustion gas is ejected from the first combustion gas ejection section, and the second combustion gas is ejected by the second combustion gas swirl ejection means. Diffusing, mixing, and burning with the primary air and the lean primary combustion gas ejected from the combustion chamber, and at the same time, the secondary air is ejected from the center of the flame plate by the centrifugal force of the swirling flow Completely combusts because it also diffuses and mixes with the secondary air supplied from the section.

  In other words, the second combustion gas is diffused and mixed with the primary air ejected from the first combustion gas ejection section by the second combustion gas swirl jetting means, burned by mixing, and further burned by the centrifugal force of the swirl flow. Since the secondary air supplied from the secondary air ejection part is also diffused, mixed and burned, the second combustion gas can be burned completely.

  Further, the second combustion gas swirl jet means is provided with a second combustion gas auxiliary jet hole for jetting the second combustion gas in the same direction as the jet direction of the first combustion gas. Part of the gas is injected from the second combustion gas auxiliary injection hole in the same direction as the injection direction of the first combustion gas, and diffuses and mixes with the secondary air supplied from the secondary air injection part and burns. The primary air and the secondary air corresponding to the ejection amount of the second combustion gas can be surely completely burned.

  Further, since the second combustion gas chamber for supplying the second combustion gas is provided upstream of the flame plate, the structure is simplified and the second combustion gas chamber is not exposed to the flame. Since the deformation and breakage of the burner parts due to heat can be prevented, the durability of the combustion apparatus can be improved.

  The combustion apparatus of the present invention will be described in detail below based on the drawings. In this embodiment, a combustion apparatus using liquid fuel as fuel will be described.

  FIG. 1 is a front cross-sectional view of a combustion apparatus, in which a vaporizer 1 that generates a premixed gas (first combustion gas) of a combustion gas and primary air that vaporizes liquid fuel, a first combustion gas, and A burner unit 2 for burning a hydrogen-containing gas (second combustion gas) generated in the fuel cell and a blower passage 3 for supplying air are provided.

  The vaporizer 1 includes a liquid fuel supply pipe 4 that supplies liquid fuel to the vaporizer 1, a heater 5 that raises the temperature of the vaporizer 1, and an evaporation unit 6 that heats and vaporizes the liquid fuel to form a combustion gas. Vaporization with a partition plate 7 provided with a dropping hole 8 for dispersing and dropping liquid fuel to the evaporation section 6 and an evaporation section 6 on the inner bottom surface to mix combustion gas and primary air into a first combustion gas A chamber 9, a supply chamber 10 that distributes the primary air that contains the air from the blower passage 3 and mixes with the combustion gas, and the secondary air that is supplied to the flame formed by the burner section 2, and the first combustion chamber It is the structure provided with the premixed gas derivation | leading-out part 11 which derives | leads-out gas.

  The premixed gas outlet 11 includes an inlet 12 that communicates with the vaporizing chamber 9 and into which the first combustion gas flows, and an outlet 13 that ejects the first combustion gas. The inlet 12 evaporates. It is provided at a position higher than the part 6.

  The burner unit 2 communicates with a premixed gas burner 14 that combusts the first combustion gas, a hydrogen-containing gas burner 15 that combusts the second combustion gas, and a flame formed by the burner unit 2 in communication with the air supply chamber 10. It consists of a secondary air passage 16 for supplying secondary air, a flame plate 17 provided with a plurality of through-holes, and a ring-like second combustion gas swirling jet means 18, and vertically below the carburetor 1. Is provided.

  The premixed gas burner 14 includes a cylindrical premixed gas passage 19, and the first combustion gas injected from the ejection port 13 of the premixed gas outlet 11 is supplied to the premixed gas passage 19.

  The hydrogen-containing gas burner 15 includes a hydrogen-containing gas supply pipe 20 that supplies the second combustion gas generated in the fuel cell, and a hydrogen-containing gas chamber (second combustion-use chamber) that is connected to the downstream end of the hydrogen-containing gas supply pipe 20. The second combustion gas discharged from the hydrogen electrode of the fuel cell is supplied to the second combustion gas chamber 21 through the hydrogen-containing gas supply pipe 20.

  The premixed gas passage 19, the second combustion gas chamber 21, and the secondary air passage 16 are connected to a flame plate 17 provided with a plurality of ejection holes as shown in FIG. The burner portion 2 is closed by the plate 17.

  Of the ejection holes provided in the flame plate 17, a premixed gas ejection hole (first combustion gas ejection hole) 22 a provided in the central portion of the flame plate 17 communicates with the premixed gas passage 19. The flame hole is configured as a premixed gas ejection part (first combustion gas ejection part) 22 for ejecting the first combustion gas, and the first combustion gas ejected from the first combustion gas ejection hole 22a is shown in the figure. It is ignited by the ignition device that does not, and starts combustion.

  A hydrogen-containing gas ejection hole (second combustion gas ejection hole) 23a provided around the first combustion gas ejection hole 22a communicates with the second combustion gas chamber 21 and is used for the second combustion. A hydrogen-containing gas jetting part (second combustion gas jetting part) 23 for jetting gas is configured.

  Further, the peripheral edge of the flame plate 17 is provided with a secondary air ejection hole 24a so as to surround the second combustion gas ejection hole 23a, and the secondary air ejection hole 24a communicates with the secondary air passage 16. And it is comprised as the secondary air ejection part 24 which ejects secondary air.

  Further, the second combustion gas swirl jet means 18 is connected downstream of the flame plate 17, and the flame plate 17 is sandwiched between the second combustion gas chamber 21 and the second combustion gas swirl jet means 18. Thus, it is provided in the burner part 2.

As shown in FIGS. 3 and 4, the second combustion gas swirl jet means 18 has a plurality of second combustion gas swirl means 18a at positions facing the second combustion gas jet holes 23a on the inner periphery of the ring. The second combustion gas swirl means 18a is provided with a second combustion gas auxiliary injection hole 18b. As shown in FIG. 5, the second combustion gas ejected from the second combustion gas ejection hole 23 a by the second combustion gas swirling means 18 a passes between the second combustion gas swirling means 18 a and the flame plate 17. Passing through the line connecting the center of the minimum circle surrounding all the first combustion gas injection holes 22a and the center of the second combustion gas auxiliary injection holes 18b, and passing through the center of the second combustion gas auxiliary injection holes 18b, the minimum being adapted to jet between the line tangent to a circle (arrow), a portion of the second combustion gas in the same direction as the ejection direction of the first combustion gas from the second combustion gas assist injection holes 18b Erupts.

  Also, a plurality of small holes 25 communicating with the secondary air injection holes 24a are provided in the vicinity of the outer periphery of the ring of the second combustion gas swirling injection means 18, and further, as shown in FIG. The outer peripheral wall is provided with secondary air turning means 26 whose end is bent toward the center downstream of the flame plate 17. Therefore, the air that has flowed into the air supply chamber 10 from the blower passage 3 is ejected from the secondary air passage 16 through the secondary air ejection holes 24 a through the small holes 25, and then by the secondary air turning means 26 to the flame plate 17. And is supplied as secondary air toward the flame formed by the burner section 2.

  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 5 is started and the vaporizer 1 is heated. When a sensor (not shown) detects that the temperature of the vaporizer 1 has reached a temperature at which the liquid fuel can be vaporized, an instruction to start supplying the liquid fuel to the vaporizer 1 is issued. The fuel is supplied to the carburetor 1 through the fuel supply pipe 4.

  The liquid fuel supplied to the vaporizer 1 falls on the partition plate 7 and spreads in all directions, and drops from the dropping hole 8 to the evaporation unit 6. Then, the liquid fuel dropped on the evaporation unit 6 is heated and vaporized to become a combustion gas and diffuses into the vaporizing chamber 9.

  At this time, part of the air supplied from the air passage 3 to the air supply chamber 10 is taken as primary air into the vaporization chamber 9 from the gap of the liquid fuel supply pipe 4, so that the combustion diffused in the primary air and the vaporization chamber 9 is performed. The first gas for combustion is mixed with the first gas.

  The first combustion gas flows from the inlet 12 into the premixed gas outlet 11 and is jetted from the jet outlet 13 into the premixed gas passage 19. In addition, since the inlet 12 is provided at a position higher than the evaporator 6, a space serving as a liquid fuel receiving tray is formed between the evaporator 6 and the inlet 12. And, since sufficient time for the liquid fuel to completely vaporize can be given by keeping the unvaporized liquid fuel in this space, the fuel in the liquid state that has not evaporated is supplied to the premixed gas deriving unit 11. There is no inflow. That is, the fuel contained in the first combustion gas ejected from the ejection port 13 to the premixed gas passage 19 is only the completely vaporized combustion gas, and the combustion state in the burner portion 2 can be maintained well. It becomes.

  Further, by providing the premixed gas lead-out portion 11, the pressure inside the vaporizing chamber 9 is raised, and the pressure fluctuation inside the vaporizing chamber 9 generated by the evaporation of the liquid fuel is reduced by this pressure rise. Therefore, the fluctuation of the combustion amount is suppressed, and the mixing of the combustion gas and the primary air is sufficiently performed, so that the first combustion gas to be ejected becomes uniform.

  Then, the first combustion gas passes through the premixed gas passage 19 and is ejected from the first combustion gas ejection portion 22 provided at the center of the flame plate 17, and is ignited by an ignition device (not shown) and premixed gas burner 14. Combustion at is started.

  At this time, secondary air is ejected from the secondary air ejection part 24, and when this secondary air passes through the small hole 25 of the second combustion gas swirl ejection means 18, the secondary air turning means 26 The jet direction is changed to the center direction of the flame plate 17 and supplied toward the flame formed by the combustion of the first combustion gas. Therefore, since the secondary air and the flame are effectively mixed, the first combustion gas is completely burned.

  Thus, the reformer is heated by burning the first combustion gas. Then, when the temperature of the reformer rises to the operating temperature, generation of reformed gas mainly composed of hydrogen from kerosene as raw fuel such as hydrocarbon is started, and the reformed gas mainly composed of hydrogen is supplied to the fuel cell. Then, the fuel cell is activated and the 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 for the second combustion while containing unreacted hydrogen gas of about several tens of percent. The gas is discharged from the hydrogen electrode of the fuel cell and used for combustion in the combustion device.

  Specifically, the second combustion gas discharged from the hydrogen electrode is supplied to the second combustion gas chamber 21 through the hydrogen-containing gas supply pipe 20 and ejected from the second combustion gas ejection portion 23. Then, the second combustion gas is jetted as a swirling flow toward the first combustion gas jetting portion 22 of the flame plate 17 whose jetting direction is changed by the second combustion gas swirling means 18a, and has already been first burned. Since it is ignited and combusted by coming into contact with the flame formed in the working gas jetting part 22, combustion by both the first combustion gas and the second combustion gas is started.

  By the way, immediately after the reformer is activated, the supply of the reformed gas mainly composed of hydrogen to the fuel cell is not stable, and the amount of the second combustion gas discharged from the fuel cell is also unstable. Therefore, since it is difficult to maintain stable combustion only with the second combustion gas, the combustion by both the first combustion gas and the second combustion gas is continued for a while after the operation of the reformer. .

  When the operation of the fuel cell is stabilized, the combustion is mainly performed with the second combustion gas. At this time, primary air or lean first combustion gas is ejected from the first combustion gas ejection hole 22a, and the second combustion gas is ejected by the second combustion gas swirling means 18a. The primary air or the lean first combustion gas ejected from the hole 22a is swirled and mixed as a swirl flow, and simultaneously burned. At the same time, the swirl flow centrifugal force causes the swirl flow to be ejected outside the center of the flame plate 17. Since the secondary air supplied from the secondary air ejection holes 24a is also diffused and mixed to burn, complete combustion is possible.

  In other words, the second combustion gas is diffused and mixed with the primary air ejected from the first combustion gas ejection hole 22a by the second combustion gas swirling means 18a, and burned by mixing and mixing. As a result, the secondary air supplied from the secondary air ejection holes 24a is also diffused, mixed and combusted, so that the second combustion gas can be completely combusted.

  Further, the second combustion gas auxiliary injection hole 18b provided in the second combustion gas swirling means 18a causes part of the second combustion gas injected from the second combustion gas injection hole 23a to be the second combustion gas. The secondary combustion gas is ejected from the auxiliary ejection hole 18b in the same direction as the ejection direction of the first combustion gas, and is diffused and mixed with the secondary air supplied from the secondary air ejection hole 24a and burned. Complete combustion can be ensured by primary air and secondary air according to the quantity.

  Further, since the second combustion gas chamber 21 for supplying the second combustion gas is provided upstream of the flame plate 17, the structure is simplified and the second combustion gas chamber 21 is exposed to the flame. Therefore, the burner parts can be prevented from being deformed or damaged by heat, so that the durability of the combustion apparatus can be improved. The shape of the second combustion gas swirl means 18a is not limited to the embodiment.

  Further, in the present embodiment, the fuel gas combustion apparatus in which the liquid fuel is vaporized has been described, but the second combustion gas swirl of the present embodiment is also applied to a combustion apparatus using a gaseous fuel gas such as city gas, natural gas, LPG, etc. The ejection means 18 can be adapted.

17 Flame plate 18 Second combustion gas swirl injection means 18a Second combustion gas swirl means 18b Second combustion gas auxiliary ejection hole 21 Hydrogen-containing gas chamber (second combustion gas chamber)
22 Premixed gas ejection section (first combustion gas ejection section)
22a Premixed gas injection hole (first combustion gas injection hole)
23 Hydrogen-containing gas ejection part (second combustion gas ejection part)

Claims (5)

A combustion apparatus for burning a second combustion gas after burning the first combustion gas, wherein the second combustion gas ejection part surrounds the first combustion gas ejection part provided in the central part A flame plate, a second combustion gas chamber in communication with the second combustion gas ejection portion upstream of the flame plate, and a first combustion gas ejection direction downstream of the flame plate . The second combustion gas is ejected so as to be a swirling flow about the axis of the first combustion gas ejection direction at a substantially right angle direction, and the second combustion gas is ejected in the first combustion gas ejection direction . A combustion apparatus comprising a second combustion gas swirling jetting means for jetting.   The second combustion gas swirl jet means is a second combustion so as to form a swirl flow in a direction substantially perpendicular to the jet direction of the first combustion gas and about the axis of the jet direction of the first combustion gas. The second combustion gas swirling means for ejecting the combustion gas and the second combustion gas auxiliary ejection hole for ejecting the second combustion gas in the ejection direction of the first combustion gas. The combustion apparatus according to 1. The second combustion gas swirling means includes a center of a minimum circle surrounding all the first combustion gas ejection holes provided in the first combustion gas ejection section and a center of the second combustion gas auxiliary ejection hole. connecting lines and the second combustion gas assist injection holes around claim 2 Symbol placing the combustion apparatus is characterized by jetting a second combustion gas between the line tangent as the smallest circle of. The said 2nd combustion gas swirl jet means is further provided with the small hole which ejects secondary air so that the said 2nd combustion gas swirl means may be surrounded. Combustion device. The secondary air diverting means is further provided downstream of the second combustion gas swirl jetting means to jet secondary air in a direction substantially perpendicular to the jetting direction of the first combustion gas. 4. The combustion apparatus according to 4.

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