JP2001050514A - All primary air burner and boiler equipped with the burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an all primary air mixing burner capable of lowering NOX. SOLUTION: An air nozzle 3A and a gas fuel nozzle 4A are disposed at a throat portion 2A of a burner tile 2, and an all-primary air mixing burner is provided for mixing and combusting fuel gas and air injected from both nozzles 3A, 4A. A combustion gas supply passage 4 is inserted into a combustion air supply passage 3 through which air is supplied to the air nozzle 3A, and a small sized auxiliary burner Aa is inserted into the combustion gas supply passage located in the combustion air supply passage, and further a combustion flame formation portion of the auxiliary burner Aa is provided on an more upper side in a gas supply direction than a combustion region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burner used, for example, for an industrial furnace or a boiler, in which a gas fuel nozzle is inserted into a combustion oxygen-containing gas nozzle, and tips of both nozzles are burner tiles. The present invention relates to an all-primary pneumatic burner which forms a main combustion flame in the combustion region by mixing gases supplied from both ends while facing a combustion region surrounded by.

[0002]

2. Description of the Related Art A characteristic required for a burner is a low NO.
It is required that the burner structure be adapted to _X- ization. Therefore, conventionally, a two-stage combustion system, a split flame system, and a system such as an exhaust gas recirculation system in which exhaust gas once burned is mixed with combustion air has been used.

[0003]

If such a system is employed, there is a disadvantage that the burner structure itself becomes complicated when the other system is employed. On the other hand, the method of (1) requires a blower and a pipe for circulation, and has a problem of increasing the number of parts and increasing the size of the structure.

An object of the present invention is in providing a boiler having a primary aerated burner and burner that will not lead to increase in the size of the burner structure while attaining low N0 _X reduction, operational effects thereof It is as follows.

[0005]

According to a first aspect of the present invention, the gas fuel supply path is inserted into the combustion oxygen-containing gas supply path from the middle of the combustion oxygen-containing gas supply path and an auxiliary burner is inserted. Is inserted into the gas fuel supply passage, and a combustion flame forming portion of the auxiliary burner (an auxiliary combustion flame is formed at this portion) is located in the gas fuel supply passage. The effects are as follows. [Operation] The combustion exhaust gas from the auxiliary burner forming the auxiliary combustion flame is sent to the combustion region together with the gaseous fuel and mixed with the oxygen-containing gas for combustion. At this time, since the combustion exhaust gas is an inert gas and does not contribute to the combustion reaction, it delays the combustion reaction of the gaseous fuel, so that the combustion temperature in the main combustion flame decreases, the combustion state becomes a slow combustion state, and the low NO. _X conversion is achieved. [Effect] Thus, by providing an auxiliary burner, it was possible to achieve low N0 _X reduction. Moreover, its low N0
_As a means of achieving _X conversion, the burner body such as a burner tile is not modified, but as it is, an auxiliary burner is added in the strong combustion oxygen-containing gas supply path of the accessory element. There is also a good point that it does not become large enough to remodel the burner body.

In adopting the above structure, as described in claim 2, the gas fuel supply passage is inserted into the combustion oxygen-containing gas supply passage in the middle of the passage, and the auxiliary burner is installed. A gas flame supply path inserted into the combustion oxygen-containing gas supply path is inserted into the combustion fuel-containing gas supply path midway, and a combustion flame forming portion of the auxiliary burner (an auxiliary combustion flame is formed at this portion); What is necessary is just to position it in the upstream of the combustion area in the gas fuel supply direction. In this case, for example, a gas fuel supply path is formed in the inner pipe of the double pipe, a flow path formed between the inner pipe and the outer pipe is formed as a combustion oxygen-containing gas supply path, and the double pipe is bent. An auxiliary burner is inserted into the inner pipe from outside the double pipe in the bent section from outside the double pipe to form an auxiliary combustion flame in the gas fuel supply passage. In the case of such a configuration, it is possible to obtain a burner that can achieve the above-described effects with a relatively compact configuration.

[Structure] According to a third aspect of the present invention, in the first or second aspect of the present invention, the auxiliary burner is configured to place the oxygen-containing gas for combustion and the gaseous fuel on the upper side of the combustion region. In that it is a premix burner, or a premix burner that mixes the oxygen-containing gas for combustion and gaseous fuel in the combustion zone.
The operation and effect are as follows. (Effects)
As an auxiliary burner, the main role is to supply exhaust gas after combustion, so there is no problem with the mechanism for generating exhaust gas, so use either the original mixing type or the pre-mixing type. And the degree of freedom in design is great.

[Structure] A feature of the invention according to claim 4 is that the boiler is provided with the burner according to claim 1, 2 or 3, and its operation and effect are as follows. [Operation and effect] The operation and effect are the same as those of the first, second or third aspect. In addition, by being used for the boiler thereon, the burner function is effectively exhibited.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a burner tile 2 is provided which opens toward a combustion chamber 1 on which an object to be heated (not shown) is placed, and combustion air as an oxygen-containing gas for combustion is provided. Is provided, and an air nozzle 3A as a combustion oxygen-containing gas nozzle is provided at the tip of the combustion air supply passage 3, and the air nozzle 3A is connected to the throat 2A of the burner tile 2, and A gas supply path 4 for supplying combustion gas is inserted in the middle of the combustion air supply path 3, and a gas fuel nozzle 4A is provided at the tip of the gas supply path 4 so that the gas fuel nozzle 4A is located in the air nozzle 3A. Thus, an all-primary pneumatic burner is configured. The gas fuel nozzle 4A and the air nozzle 3A open to the throat 2A of the burner tile 2 and mix the gas emitted from both nozzles 4A, 3A in the internal space of the burner tile 2 (part of the combustion area). A premixed burner structure for forming a combustion flame is formed.

Next, the auxiliary burner Aa will be described.
As shown in FIG. 1, the auxiliary burner Aa connects the combustion air supply path 5 and the combustion gas supply path 6 to an auxiliary burner nozzle 7 and performs a gas mixing at a junction of the two paths 5 and 6. Is formed. The auxiliary burner Aa is provided with an igniter at a predetermined position, and is configured to be ignitable and combustible only by the burner. As the type of the auxiliary burner Aa, an original mixing type is adopted. However, an air nozzle and a gas fuel nozzle are separately provided so that the auxiliary combustion flame is formed at a position where the gas is formed at a position higher than the combustion flame formation position at the tip of the gas fuel nozzle 4A. If the fuel supply direction is good, a premixing type in which gas is mixed and burned in front of both nozzles may be adopted. The auxiliary burner nozzle 7 is inserted into a gas supply passage inserted into the pipe from a point along the combustion air supply passage 3.

As described above, by setting the combustion flame forming position of the auxiliary burner Aa upstream of the combustion region in the gas supply direction, an auxiliary combustion flame is formed at the tip of the auxiliary burner nozzle 7 and the combustion of the auxiliary burner Aa is performed. flue gas CO _2, H ₂ O generated by is to delay combustion reaction in the combustion area is an inert gas, it is possible to reduce the NO _X reduction by slow combustion.

[0012] As a demonstration example of the low NO _X can be achieved,
A graph as shown in FIG. 2 is obtained. Here, for convenience, the burner portion composed of the air nozzle 3A and the gas fuel nozzle 4A is referred to as a main burner, and this figure will be described. the nO _X level when the vertical axis without using the auxiliary burner Aa represents the nO _X reduction rate was 100%,
The NO _x reduction rate corresponding to the combustion ratio of the auxiliary burner Aa to the main burner is graphed. Regarding the relationship between the NO _X reduction rate and the combustion rate of the auxiliary burner Aa, the NO _X tends to decrease as the combustion amount of the auxiliary burner Aa increases.

[0013] Since the auxiliary burner Aa is burned in the gas supply path 3, the temperature in the pipe rises. Therefore, it is necessary to use a heat-resistant material as a material for the gas supply path 3. Even if a material having an insulative property is used, the combustion amount of the auxiliary burner Aa should be set to 1 to 20% of the main burner which forms the main combustion flame in the combustion region, from the viewpoint of avoiding burning of the pipeline. desirable. Here, the burning amount of the burner indicates the amount of gas fuel injected per unit time for burning the burner, and indicates the burning capacity of the burner.

An example in which the above-described burner is applied to a boiler B will be described. As shown in FIG. 3, the boiler B has a number of water tubes 9 arranged vertically in a can 8, and a water header 10 and a brackish header 11 connected to the water tube 3 on the upper and lower surfaces of the can 8, respectively. And a burner for heating the water pipe 3 from the lateral direction is provided. A combustion air supply path 3 having a blower 14 and a damper 15 is provided on the upper side of the can body 8, and a combustion gas supply path 4 for supplying gas through a control valve 16 is connected to the combustion air supply path 4. Insert into Road 3,
An exhaust flue 13 connected to the chimney 12 is provided on the lower side of the can body 8, and an exhaust treatment structure is formed.

[Other Embodiments] (1) As described above, the auxiliary burner Aa may be not only the original mixing type but also a pre-mixing type. (2) The boiler to which the above-described burner device is applied may be a boiler of another type other than the water tube type. (3) In the above-described embodiment, the case where the gas fuel and the oxygen-containing gas for combustion are discharged from the nozzle portion has been described. And

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing an all-primary pneumatic burner.

FIG. 2 shows the combustion amount NO _{X of the} auxiliary burner with respect to the main burner.
Diagram showing reduction rate

FIG. 3 is a configuration diagram showing an example applied to a water pipe boiler.

[Explanation of symbols]

 2 Burner tile 3 Oxygen-containing gas supply path for combustion 3A Air nozzle 4 Gas supply path 4A Gas fuel nozzle Aa Auxiliary burner

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Hirano 4-1-2, Hiranocho, Chuo-ku, Osaka City, Osaka Prefecture Inside Osaka Gas Co., Ltd. (72) Inventor Hirokazu Ichiki Hiranocho, Chuo-ku, Osaka City, Osaka 1-2 1-2 Osaka Gas Co., Ltd. (72) Inventor Yoshinobu Nagata 4-1-2 1-2 Hirano-cho, Chuo-ku, Osaka City, Osaka Prefecture (72) Inventor Tetsu Minami Hirano, Chuo-ku, Osaka City, Osaka Prefecture 4-1-2 cho, Osaka Gas Co., Ltd. F-term (reference) 3K017 AA06 AB02 AB06 AC02 AD01 AD06 AD11 AG02 3K019 AA06 BA02 BB02 BD03 BD09 CC02

Claims (4)

[Claims] 1. A gas fuel nozzle is inserted into an oxygen-containing gas nozzle for combustion, the tips of both nozzles are exposed to a combustion area surrounded by burner tiles, and gases supplied from both tips are mixed and mixed. An all-primary pneumatic burner that forms a main combustion flame in a combustion region, wherein the gas fuel supply passage is inserted into the combustion oxygen-containing gas supply passage from somewhere in the passage, and the auxiliary burner is connected to the gas fuel supply passage. An all-primary pneumatic burner inserted in a passage, wherein a combustion flame forming portion of the auxiliary burner is located in the gas fuel supply passage. 2. A gas fuel nozzle is inserted into the oxygen-containing gas nozzle for combustion, and the tips of both nozzles face the combustion area surrounded by burner tiles, and the gases supplied from both tips are mixed and mixed. An all-primary pneumatic burner that forms a main combustion flame in a combustion region, wherein the gas fuel supply path is inserted from the middle of the combustion oxygen-containing gas supply path, and an auxiliary burner is connected to the combustion oxygen-containing gas. An all-primary pneumatic burner, which is inserted into the gas fuel supply path inserted into the supply path from the middle of the gas supply path, and a combustion flame forming portion of the auxiliary burner is located in the gas fuel supply path. 3. An auxiliary mixing burner for mixing the combustion oxygen-containing gas and the gaseous fuel on the upstream side of the combustion region, or mixing the combustion oxygen-containing gas and the gaseous fuel in the combustion region. The all-primary pneumatic burner according to claim 1 or 2, which is a premix burner. 4. A boiler equipped with the all-primary pneumatic burner according to claim 1, 2 or 3.