JP7435328B2 - combustion device - Google Patents

Description

The present invention relates to a combustion device that burns fuel gas containing hydrogen gas.

Conventionally, a fuel gas pipe through which fuel gas flows, a flame stabilizer connected to the downstream side of the fuel gas pipe, and a flame stabilizer arranged to surround the fuel gas pipe, in which combustion air is placed between the outer peripheral surface of the fuel gas pipe and the fuel gas pipe. A combustion device such as a boiler has been proposed, which is equipped with a burner outer cylinder through which fuel gas flows, and a pre-mixing main burner that mixes and burns fuel gas and combustion air on the downstream side of the fuel gas piping (for example, (See Patent Document 1).
In addition, a combustion device including a pre-mixing main burner has also been proposed, which further includes a pilot burner that is disposed near the main burner and is ignited before the main burner is ignited.

Japanese Patent Application Publication No. 2001-201019

When starting combustion in such a combustion device, first, the pilot burner is ignited with fuel being supplied to the pilot burner and combustion air being supplied from the burner outer cylinder. Next, with the pilot burner ignited, fuel gas is supplied to the main burner, thereby igniting the main burner and starting combustion.

If hydrogen gas, which has a wide combustible range when mixed with air, is used as the fuel gas supplied to the main burner, the combustion equipment, including the fuel gas piping, must be It is required to perform purging with an inert gas such as nitrogen to supply the inside.
In this way, when purging with inert gas is performed before starting combustion, the pilot burner is ignited and combustion occurs with inert gas remaining in the main burner and fuel gas piping. The flame of the pilot burner was sometimes unstable due to the influence of active gas.

Therefore, an object of the present invention is to provide a combustion device that can stably maintain the flame of a pilot burner.

The present invention provides a first gas flow pipe forming a first gas flow path through which a first gas containing hydrogen flows, a first flame stabilizer connected to the downstream side of the first gas flow pipe, and a first flame stabilizer connected to the downstream side of the first gas flow pipe. a burner outer cylinder that surrounds a first gas distribution pipe and forms a first combustion air flow path between which combustion air flows and an outer circumferential surface of the first gas flow pipe; Combustion comprising: a second gas flow pipe forming a gas flow path; and a pilot burner having a combustion air flow pipe forming a second combustion air flow path through which combustion air mixed with the second gas flows. Regarding equipment.

Further, the combustion air distribution pipe supplies combustion air to the second gas distribution pipe, and a premixed gas of the second gas and combustion air flows through the second gas distribution pipe. is preferred.

Preferably, the pilot burner further includes a second flame stabilizer disposed downstream of the second gas flow pipe, and the second gas flow pipe is preferably disposed in the first gas flow passage. .

Further, the second flame stabilizer includes a plate-shaped flame stabilizer disposed so as to partially block the second gas flow path, and a flame stabilizer tube disposed downstream of the flame stabilizer. The distance L between the flame stabilizing member and the tip of the flame stabilizing tube is set within a range that satisfies the relationship 0.5D≦L≦1.5D with respect to the diameter D of the flame stabilizing tube. It is preferable that

Further, it is preferable that the tip of the flame stabilizing cylinder be located downstream of the tip of the first gas flow pipe.

The combustion device further includes a flame detector disposed outside the first gas distribution pipe, and the first flame stabilizer has a base end located at a downstream end of the first gas distribution pipe. The first flame stabilizer has a plurality of flame stabilizers connected to each other, each having a truncated conical shape whose tip part widens toward the downstream side of the flow of the first gas, and a plurality of flame stabilizers through which the combustion air flows. A through hole is formed, and among the plurality of through holes, a through hole located at a position where an axis extending from the flame detector in parallel with the tube axis of the first gas distribution pipe intersects with the flame detector Preferably, it is larger than the pore.

The combustion device also includes an inert gas supply pipe that is connected to the first gas distribution pipe and supplies an inert gas to the first gas distribution pipe; It is preferable to further include a control unit configured to supply inert gas from the inert gas supply pipe to the first gas distribution pipe in a stopped state.

According to the combustion device of the present invention, the flame of the pilot burner can be maintained stably.

1 is a diagram showing the overall configuration of a combustion device according to a first embodiment of the present invention. It is an enlarged view showing a second flame stabilizer portion of the pilot burner according to the first embodiment. FIG. 3 is an exploded perspective view showing the second flame stabilizer shown in FIG. 2. FIG. It is a figure showing the whole composition of a combustion device concerning a 2nd embodiment of the present invention.

Hereinafter, preferred embodiments of the combustion apparatus of the present invention will be described with reference to the drawings. The combustion device 1 is a combustion device that burns hydrogen gas as a fuel gas, and in the embodiment is applied to a steam boiler that burns hydrogen gas to generate steam.
A steam boiler consists of a can in which a combustion chamber is formed, a plurality of water pipes extending vertically inside the can, and a lower end of the water pipes arranged at the bottom of the can. A lower header is connected to store the water supplied to the water pipes, and a lower header is placed at the top of the can body to which the upper ends of multiple water pipes are connected and the steam generated by heating the water inside the water pipes is introduced. It includes an upper header (the can body, water tube, lower header, and upper header are all not shown) and a combustion device 1 that is disposed on the upper part of the can body and heats the inside of the can body.

The combustion device 1 includes a main burner 10 that burns a first gas containing hydrogen as a main fuel, a pilot burner 20 that burns a second gas as a fuel before the main burner 10 starts burning the first gas, and a main burner 10 that burns a first gas containing hydrogen as a main fuel. 10 and a flame detector 30 that detects a flame formed in the pilot burner 20, an ignition device 40, and a control unit 90 that controls combustion of the combustion device 1. The combustion device 1 also includes a first gas supply line L1 that supplies the first gas to the main burner 10, and an inert gas supply line L2 that serves as an inert gas supply pipe that supplies inert gas to the main burner 10. A second gas supply line L3 that supplies the second gas to the pilot burner 20 is provided.

The main burner 10 is arranged at the upper part of the can body, and includes a first gas flow pipe 11, a first flame stabilizer 12, and a burner outer cylinder 13.
The first gas flow pipe 11 is arranged to extend in the vertical direction, and its lower end is located inside the can (combustion chamber). The upper end side of the first gas distribution pipe 11 is connected to the first gas supply line L1. A first gas flow path is formed inside the first gas flow pipe 11, through which the first gas flows vertically downward.

The first flame stabilizer 12 is connected to the lower end of the first gas flow pipe 11 . The first flame stabilizer 12 is constituted by a truncated conical tubular member that expands downward. The diameter of the upper end of the first flame stabilizer 12 is configured to be approximately the same as the diameter of the lower end of the first gas flow pipe 11 .

A plurality of through holes 121 are formed in the circumferential surface of the first flame stabilizer 12 . The through holes 121 are formed in multiple rows at predetermined intervals in the vertical direction (expansion direction). Further, a plurality of through holes 121 are formed in each row at predetermined intervals in the circumferential direction. The size of the through holes 121 gradually increases from the upper end row to the lower end row.
In the embodiment, one of the through holes 121a formed in the uppermost row is larger than the other through holes 121 in the same row. The large-diameter through-hole 121a is arranged at a position directly below (vertically downward) a flame detector 30, which will be described later.

The burner outer cylinder 13 has a cylindrical shape and is arranged coaxially with the first gas flow pipe 11 so as to surround the first gas flow pipe 11 and the first flame stabilizer 12 . The upper end side of the burner outer cylinder 13 is disposed in an upwardly opened state inside a wind box 60 serving as a combustion air supply path through which combustion air is supplied. The lower end of the burner outer cylinder 13 is located below the lower end of the first flame stabilizer 12 . The inner diameter of the burner outer cylinder 13 is set to be slightly larger than the outer diameter of the lower end of the first flame stabilizer 12 . A first combustion air flow passage through which combustion air supplied through the wind box 60 flows is formed between the burner outer cylinder 13 and the outer peripheral surface of the first gas flow pipe 11 .

The pilot burner 20 is arranged near the main burner 10 and includes a second gas flow pipe 21, a combustion air flow pipe 22, and a second flame stabilizer 23.
The second gas flow pipe 21 is arranged to extend in the vertical direction. In the first embodiment, the second gas flow pipe 21 is configured to have a smaller diameter than the first gas flow pipe 11, and is arranged coaxially with the first gas flow pipe 11 inside the first gas flow pipe 11. That is, the second gas flow pipe 21 is arranged in the first gas flow path. The upper end side of the second gas distribution pipe 21 is connected to the second gas supply line L3.

The combustion air flow pipe 22 forms a second combustion air flow path through which combustion air mixed with the second gas combusted in the pilot burner 20 flows. In the first embodiment, the upstream side of the combustion air flow pipe 22 is connected to the wind box 60, and the downstream side is connected to the second gas supply line L3. That is, in the first embodiment, the combustion air distribution pipe 22 is connected to the second gas distribution pipe 21 via the second gas supply line L3. As a result, a premixed gas of the second gas and combustion air flows through the second gas distribution pipe 21 . An air opening/closing valve 221 that opens and closes the second combustion air flow path is arranged in the combustion air distribution pipe 22 .
The air ratio of the premixed gas (mixed gas of the second gas and combustion air) is set from 1 to 1.0 from the viewpoint of suitably detecting the flame formed in the pilot burner 20 in the flame detector 30, which will be described later. It is preferable that it is 2. By adjusting the air ratio from 1 to 1.2, the length of the flame formed in the pilot burner 20 can be increased.

The second flame stabilizer 23 is arranged on the downstream side of the second gas flow pipe 21. In the first embodiment, the second flame stabilizer 23 is connected to the lower end of the second gas flow pipe 21. The second flame stabilizer 23 includes a flame stabilizing member 231 and a flame stabilizing cylinder 232, as shown in FIGS. 2 and 3.

The flame stabilizing member 231 is made of a disc-shaped member in which a central through hole 234 is formed in the center, and a plurality of peripheral through holes 235 are formed around the central through hole 234 at predetermined intervals in the circumferential direction. configured. The flame stabilizing member 231 has a concave surface in the form of a mortar whose upper surface side slopes downward toward the central through hole 234, and a peripheral through hole 235 is formed in this concave surface. The outer diameter of the flame stabilizing member 231 is formed to be approximately the same diameter as the inner diameter of the lower end portion of the second gas flow pipe 21 . The flame stabilizing member 231 is joined to the lower end of the second gas flow pipe 21 by welding or the like, and partially blocks the second gas flow path.

The flame-holding cylinder 232 is formed of a cylindrical member having approximately the same diameter as the second gas distribution pipe 21, and is connected to the lower end of the second gas distribution pipe 21 so as to be coaxial with the second gas distribution pipe 21. . In the first embodiment, the lower end of the flame stabilizing tube 232 is located lower than the lower end of the first gas distribution pipe 11 . Further, the lower end portion of the flame stabilizing cylinder 232 is located above the uppermost through hole 121 of the plurality of through holes 121 formed in the first flame stabilizer 12 .
The length of the flame-holding tube 232 (distance between the flame-holding member 231 and the tip of the flame-holding tube 232, in other words, the distance between the flame-holding member 231 and the lower end of the pilot burner 20) L; The inner diameter D of the flame stabilizing cylinder 232 (inner diameter of the second gas flow pipe 21) is within the range of 0.5D≦L≦1.5D from the viewpoint of ensuring flame stabilization in the second flame stabilizer 23. It is preferable that this is set.

In the first embodiment, the second flame stabilizer 23 has been described as being constituted by the flame stabilizing member 231 and the flame stabilizing tube 232, but the present invention is not limited to this. That is, the second flame stabilizer 23 may be configured by only the flame stabilizer 231, and the flame stabilizer 231 may be joined and disposed a predetermined length above the lower end of the second gas flow pipe 21. In other words, the second gas distribution tube is a combination of the second gas distribution tube 21 and the flame stabilizing tube 232 of the first embodiment, and the second gas distribution tube is placed a predetermined length upward from the lower end of the second gas distribution tube. The pilot burner may be configured by arranging a flame holding tube as a flame weapon.

The flame detector 30 is arranged above the first flame holder 12 in the vertical direction. The flame detector 30 detects the flame formed by the main burner 10 or the pilot burner 20 through the wind box 60, the first combustion air flow path, and the through hole 121a formed in the first flame stabilizer 12. The flame detector 30 includes an optical sensor 31 such as an ultraviolet flame detector capable of detecting flame.

The ignition device 40 includes a spark rod 41 that performs ignition at its tip, and is arranged inside the second gas distribution pipe 21 along the second gas distribution pipe 21 . The ignition device 40 ignites the premixed gas of the second gas and combustion air ejected from the second gas distribution pipe 21 .

The first gas supply line L1 supplies the first gas to the main burner 10 (first gas distribution pipe 11). In the first embodiment, hydrogen gas is used as the first gas. A first gas on-off valve 61 that opens and closes the first gas supply line L1 is arranged in the first gas supply line L1.
The inert gas supply line L2 supplies inert gas to the main burner 10. In the first embodiment, the inert gas supply line L2 is connected downstream of the first gas on-off valve 61 in the first gas supply line L1, and supplies inert gas to the main burner 10 through the first gas supply line L1. supply For example, nitrogen gas is used as the inert gas. An inert gas on-off valve 62 that opens and closes the inert gas supply line L2 is arranged in the inert gas supply line L2.
The second gas supply line L3 supplies the second gas to the pilot burner 20. In the first embodiment, a hydrocarbon gas such as liquefied petroleum gas (LPG) or city gas is used as the second gas. A second gas on-off valve 63 that opens and closes the second gas supply line L3 is arranged on the second gas supply line L3.

The control unit 90 controls combustion in the combustion device 1 by controlling the opening and closing of various valves and the operation of the ignition device 40.

Hereinafter, combustion control of the combustion device 1 by the control section 90 will be explained.
When starting combustion by the combustion device 1, the control unit 90 first closes the first gas on-off valve 61, opens the inert gas on-off valve 62, and starts an inert gas purge to supply inert gas to the main burner 10. (prepurge). Additionally, a blower (not shown) is driven to introduce combustion air into the wind box 60. Thereby, inert gas is supplied to the first gas flow pipe 11 (first gas flow path) in the main burner 10 and the main burner 10 . In addition, combustion air is supplied from the wind box 60 to the inside of the can through the burner outer cylinder 13 to perform air purging inside the can.

After performing the inert gas purge, the control unit 90 ignites the pilot burner 20. Specifically, the control unit 90 closes the inert gas on-off valve 62, opens the second gas on-off valve 63 and the air on-off valve 221, and supplies the second gas and combustion air to the second gas distribution pipe 21. Supply premixed gas. Further, the premixed gas is ignited by the ignition device 40, and the pilot burner 20 is ignited. Here, the pilot burner 20 is supplied with combustion air for igniting the pilot burner, which is mixed with the second gas. Thereby, even if inert gas remains in the main burner 10 due to the inert gas purge, combustion in the pilot burner 20 will not be inhibited by the influence of this inert gas. Therefore, the flame of the pilot burner 20 can be maintained stably. Further, the flame formed in the pilot burner 20 is stably maintained in the second flame holder 23.
The flame of the pilot burner 20 is detected by a flame detector 30.

After the pilot burner 20 is ignited (after the flame of the pilot burner 20 is detected by the flame detector 30), the control unit 90 ignites the main burner 10. Specifically, the control unit 90 opens the first gas on-off valve 61 and supplies hydrogen gas, which is the first gas, to the first gas distribution pipe 11 (first gas distribution path) through the first gas supply line L1. do. The hydrogen gas ejected from the first gas flow pipe 11 through the first gas flow path is combined with the combustion air supplied from the upstream side of the first flame holder 12 through the plurality of through holes 121 in the first flame holder 12. They are mixed (pre-mixed) and ignited by the flame of the pilot burner 20. Furthermore, it is mixed with combustion air that is blown out from the gap between the first flame stabilizer 12 and the burner outer cylinder 13, and is combusted.
After the main burner 10 is ignited, the control unit 90 closes the second gas on-off valve 63 and stops combustion in the pilot burner 20. Note that by leaving the air on-off valve 221 open without closing it, the supply of combustion air to the pilot burner 20 is continued even during combustion in the main burner 10, so that the pilot burner 20 is not overheated. You can prevent this from happening.
The flame of the main burner 10 is also detected by the flame detector 30.

When stopping combustion in the main burner 10, the control unit 90 closes the first gas on-off valve 61. As a result, the supply of hydrogen gas to the main burner 10 is stopped, and the flame is extinguished. Extinguishing the flame is detected by the flame detector 30.
After combustion in the main burner 10 is stopped, the control unit 90 opens the inert gas on-off valve 62 and performs inert gas purge (post purge) again. After performing the inert gas purge, the control unit 90 closes the inert gas on-off valve 62 and stops driving the blower.

According to the combustion device 1 of the first embodiment described above, the following effects are achieved.

(1) The combustion device 1 is configured to include a pre-mixing main burner 10 that burns a first gas containing hydrogen, and a pilot burner 20, and the pilot burner 20 is a second gas through which a second gas flows. It is configured to include a gas flow pipe 21 and a combustion air flow pipe 22 through which combustion air mixed with the second gas flows. Thereby, when igniting the pilot burner 20, combustion air can be suitably supplied to the second gas through the combustion air distribution pipe 22. Therefore, even when the first gas containing hydrogen gas is used as the combustion gas of the main burner 10 and the first gas distribution pipe 11 is purged with an inert gas, the pilot burner 20 may be damaged due to the influence of the inert gas. Since combustion is not inhibited, the pilot burner flame can be maintained stably.

(2) Connect the combustion air distribution pipe 22 to the base end side of the second gas distribution pipe 21 via the second gas supply line L3, and connect the second gas and combustion air to the second gas distribution pipe 21. A premixed gas was passed through. Thereby, the pilot burner 20 can be configured in a premixing type, so the pilot burner 20 can be configured simply.

(3) The pilot burner 20 was configured to include a second flame stabilizer 23, and the second gas flow pipe 21 was arranged in the first gas flow path. As a result, the pilot burner 20 can be arranged inside the first gas distribution pipe 11 instead of the first combustion air flow path formed inside the burner outer cylinder 13, so that combustion in the first combustion air flow path is possible. The combustion device 1 can be configured without disturbing the flow of air. Therefore, the combustion state of the combustion device 1 can be made more stable. Moreover, the combustion device 1 can be downsized.

(4) The second flame stabilizer 23 is configured to include a flame stabilizer 231 and a flame stabilizer tube 232, and the distance L between the flame stabilizer 231 and the tip of the flame stabilizer tube 232 is The diameter D of the flame cylinder 232 is set within a range that satisfies the relationship 0.5D≦L≦1.5D. As a result, when the first gas distribution pipe 11 is purged with an inert gas, the inert gas ejected from the first gas distribution pipe 11 enters the inside of the second flame stabilizer 23 (flame stabilizer 232) and is protected. The flame formed downstream from the flame member 231 can be prevented from becoming unstable.

(5) The tip of the flame-holding cylinder 232 was positioned downstream (lower) than the tip of the first gas distribution pipe 11. Thereby, when the first gas distribution tube 11 is purged with an inert gas, it is difficult for the inert gas ejected from the tip of the first gas distribution tube 11 to enter the inside of the flame stabilizing tube 232.

(6) In the main burner 10, the flame is formed downward from the position where the uppermost through hole 121 of the plurality of through holes 121 formed in the first flame stabilizer 12 is formed. Therefore, the tip (lower end) of the flame holding tube 232 was positioned upstream (above) the position where the through hole 121 in the first flame holding device 12 was formed. Thereby, in a state where the main burner 10 is burning, heating of the pilot burner 20 by the flame formed in the first flame stabilizer 12 can be suppressed, so that the life of the pilot burner 20 can be extended.

(7) The combustion device 1 is configured to include the flame detector 30, and the first flame stabilizer 12 is configured to have a plurality of through holes 121 formed on the circumferential surface, and among the plurality of through holes 121, A through hole 121a located at a position where an axis extending parallel to the tube axis of the first gas flow pipe 11 from the flame detector 30 intersects with the flame detector 30 is formed larger than other through holes 121. As a result, the amount of light reaching the flame detector 30 from the flame formed inside the first flame holder 12 can be increased, so that the flame of the pilot burner 20 formed near the center of the first flame holder 12 can be detected more accurately.

(8) A state in which the combustion device 1 is configured to include an inert gas supply line L2 and a control section 90, and the control section 90 stops supplying the first gas to the first gas distribution pipe 11. Then, an inert gas purge was performed to supply inert gas from the inert gas supply line L2 to the first gas distribution pipe 11. Thereby, the first gas distribution pipe 11 can be purged with inert gas while the supply of the first gas containing hydrogen gas is stopped, so the safety of the combustion device 1 can be improved.

Next, a combustion device 1A according to a second embodiment of the present invention will be described with reference to FIG. 4. The combustion device 1A of the second embodiment differs from the first embodiment in the configuration of the pilot burner 20A. More specifically, in the second embodiment, the pilot burner 20A is configured as a premix burner in which combustion air and the second gas are mixed and burned downstream of the second gas distribution pipe 21A. This differs from the first embodiment in this point. In the description of the second embodiment, the same constituent elements are given the same reference numerals, and the description thereof will be omitted or simplified.

In the second embodiment, the pilot burner 20A includes a second gas flow pipe 21A, a combustion air flow pipe 22A, and a second flame stabilizer 23A.
The second gas flow pipe 21A is arranged to extend in the vertical direction. In the second embodiment, the second gas flow pipe 21A is configured to have a smaller diameter than the first gas flow pipe 11, and is arranged inside the first gas flow pipe 11 and coaxially with the first gas flow pipe 11. The upper end side of the second gas distribution pipe 21A is connected to the second gas supply line L3. A second gas flow path is formed inside the second gas flow pipe 21 . The lower end of the second gas flow pipe 21A is located above (upstream) than the lower end of the first gas flow pipe 11.

The combustion air circulation pipe 22A includes a vertical piping section 222A and a connecting piping section 223A. The vertical piping section 222A is configured to have a smaller diameter than the first gas distribution tube 11 and a larger diameter than the second gas distribution tube 21A, and is located inside the first gas distribution tube 11 and larger than the second gas distribution tube 21A. It is arranged on the outside coaxially with the first gas distribution pipe 11 and the second gas distribution pipe 21A. The downstream end (lower end) of the vertical piping section 222A is located below the lower end of the first gas distribution pipe 11. Further, the lower end portion of the vertical piping portion 222A is located above the uppermost through hole 121 of the plurality of through holes 121 formed in the first flame stabilizer 12. The connecting piping section 223A connects the wind box 60 and the upper end side of the vertical piping section 222A. An air opening/closing valve 221A that opens and closes the second combustion air flow path is arranged in the connecting piping section 223A.

In the second embodiment, only the second gas flows inside the second gas flow pipe 21A (second gas flow path), and the space outside the second gas flow pipe 21A and inside the vertical piping section 222A ( Only combustion air flows through the second combustion air flow path.

The second flame stabilizer 23A is connected to the lower end of the second gas flow pipe 21A. In the second embodiment, the second flame stabilizer 23A is constituted by a truncated conical tubular member that expands downward. The diameter of the upper end of the second flame stabilizer 23A is configured to be approximately the same as the diameter of the lower end of the second gas flow pipe 21A. Moreover, the diameter of the lower end portion of the second flame stabilizer 23A is configured to be slightly smaller than the inner diameter of the vertical piping portion 222A. The lower end of the second flame stabilizer 23A is located above the lower end of the vertical piping section 222A.

A plurality of through holes 231A are formed in the circumferential surface of the second flame stabilizer 23A. The through holes 231A are formed in multiple rows at predetermined intervals in the vertical direction (expansion direction). Further, a plurality of through holes 231A are formed in each row at predetermined intervals in the circumferential direction. The size of the through holes 231A gradually increases from the upper end row to the lower end row.
In the second embodiment, the distance L between the tip of the second flame stabilizer 23A and the tip of the combustion air flow pipe 22A (vertical piping section 222A) determines the flame stability in the second flame stabilizer 23A. From the viewpoint of ensuring a suitable diameter, it is preferable that the diameter D of the combustion air flow pipe 22A (vertical piping portion 222A) is set within a range that satisfies the relationship 0.5D≦L≦1.5D.

According to the pilot burner 20A of the second embodiment, the second gas is supplied from the lower end of the second gas distribution pipe 21A to the inside of the second flame stabilizer 23A. Further, the combustion air supplied to the upstream side of the second flame stabilizer 23A from the space between the outer circumference of the second gas distribution pipe 21A and the inner circumference of the vertical piping section 222A passes through the plurality of through holes 231A to the second flame stabilizer 23A. It is introduced inside the flame stabilizer 23A. Then, inside the second flame stabilizer 23A, the mixture of the second gas and the combustion air is ignited by the ignition device 40 to form a flame.

According to the combustion device 1A of the second embodiment described above, in addition to the effects (1), (3), (7), and (8) described above, the following effects are also achieved.

(9) The distance L between the tip of the second flame stabilizer 23A and the tip of the combustion air distribution pipe 22A (vertical piping portion 222A) is calculated as the diameter of the combustion air distribution tube 22A (vertical piping portion 222A). D is set within a range that satisfies the relationship 0.5D≦L≦1.5D. As a result, when the first gas flow pipe 11 is purged with inert gas, the inert gas ejected from the first gas flow pipe 11 enters the inside of the pilot burner 20A (combustion air flow pipe 22A) and the second gas flow pipe 11 is purged with inert gas. The flame formed downstream from the flame stabilizer 23A can be prevented from being blown out.

(10) The tip of the combustion air distribution tube 22A (vertical piping portion 222A) was positioned downstream (lower) than the tip of the first gas distribution tube 11. Thereby, when the first gas distribution pipe 11 is purged with inert gas, the inert gas ejected from the tip of the first gas distribution pipe 11 is allowed to enter the inside of the pilot burner 20A (combustion air distribution pipe 22A). It can be made difficult.

(11) In the main burner 10, the flame is formed downward from the position where the uppermost through hole 121 of the plurality of through holes 121 formed in the first flame holder 12 is formed. Therefore, the tip (lower end) of the combustion air flow pipe 22A (vertical piping section 222A) was positioned upstream (above) the position where the through hole 121 in the first flame stabilizer 12 was formed. . Thereby, in a state where the main burner 10 is burning, heating of the pilot burner 20 by the flame formed in the first flame stabilizer 12 can be suppressed, so that the life of the pilot burner 20A can be extended.

Although preferred embodiments of the combustion apparatus of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be modified as appropriate.
For example, in the first embodiment and the second embodiment, the combustion apparatus of the present invention is applied to a steam boiler, but the present invention is not limited thereto. That is, the combustion device of the present invention may be applied to a hot water boiler.

Further, in the first embodiment and the second embodiment, the pilot burners 20, 20A (second gas distribution pipes 21, 21A) were arranged in the first gas flow passage (inside the first gas flow pipe 11). It is not limited to this. That is, the pilot burner may be configured by arranging the second gas flow pipe in the first combustion air flow path (outside the first gas flow pipe and inside the burner outer cylinder).

Further, in the first embodiment and the second embodiment, a hydrocarbon gas is used as the second gas, but the invention is not limited to this. That is, hydrogen gas may be used as the second gas.

1, 1A Combustion device 11 First gas distribution tube 12 First flame holder 13 Burner outer cylinder 21, 21A Second gas distribution tube 22, 22A Combustion air distribution tube 20 Pilot burner 23, 23A Second flame holder 30 Flame Detector 90 Control part 121, 121a Through hole 231 Flame stabilizing member 232 Flame stabilizing cylinder L2 Inert gas supply line (inert gas supply pipe)

Claims (5)

a first gas flow pipe forming a first gas flow path through which a first gas using hydrogen gas as a fuel gas flows;
a first flame holder connected to the downstream side of the first gas flow pipe;
a burner outer cylinder surrounding the first gas distribution pipe and forming a first combustion air passage through which combustion air flows between the burner outer cylinder and the outer peripheral surface of the first gas distribution pipe;
A second gas flow pipe forming a second gas flow path through which a second gas flows; and a combustion air flow pipe forming a second combustion air flow path through which combustion air mixed with the second gas flows. a pilot burner having a
The combustion air flow pipe supplies combustion air to the second gas flow pipe, and a premixed gas of the second gas and combustion air flows through the second gas flow pipe,
The pilot burner further includes a second flame holder disposed downstream of the second gas flow pipe,
The second gas flow pipe is a combustion device disposed in the first gas flow path . The second flame stabilizer includes a plate-shaped flame stabilizer disposed so as to partially block the second gas flow path, and a flame stabilizer tube disposed downstream of the flame stabilizer. ,
A distance L between the flame stabilizing member and the tip of the flame stabilizing tube is set within a range that satisfies the relationship 0.5D≦L≦1.5D with respect to the diameter D of the flame stabilizing tube. The combustion device according to item 1 . 3. The combustion apparatus according to claim 2 , wherein the tip of the flame stabilizing cylinder is located downstream of the tip of the first gas distribution pipe. further comprising a flame detector disposed outside the first gas flow pipe,
The first flame stabilizer has a truncated conical shape whose base end is connected to the downstream end of the first gas flow pipe and whose tip expands toward the downstream side of the flow of the first gas. formed in
A plurality of through holes through which the combustion air flows are formed on the circumferential surface of the first flame holder,
2. A through-hole, of the plurality of through-holes, located at a position where an axis extending from the flame detector parallel to the tube axis of the first gas flow pipe intersects with the flame detector is larger than other through-holes. The combustion device according to any one of 1 to 3 . an inert gas supply pipe connected to the first gas flow pipe and supplying an inert gas to the first gas flow pipe;
Claim 1 further comprising: a control unit configured to supply inert gas from the inert gas supply pipe to the first gas distribution pipe while the supply of the first gas to the first gas distribution pipe is stopped. The combustion device according to any one of to 4 .

Images