JP2002122309A - Turning pre-mixing burner and heat source machine equipped with former - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turning pre-mixing burner wherein flame is stabilized and production of carbon monoxide is suppressed. SOLUTION: A turning pre-mixing burner comprises a cylindrical burner body 26, an injection nozzle 46 for injecting a fuel into the burner body 26, a turning blade 58 for mixing combustion air flowing in the burner body 26 and a fuel injected from the injection nozzle 46 to produce an air mixed fuel, and a flame stabilizing member 60 disposed on the side of a burner top of the burner body 26. The flame stabilizing member 60 comprises a central flame stabilizing section 62 disposed radially at the center of the burner body 26, and a plurality of connection flame stabilizing sections 64 provided at an interval peripherally of the central flame stabilizing section 60. One end of each connection flame stabilizing section is connected with the central flame stabilizing section 62, and the other end section is connected with the tip end of the burner body 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swirling type premix burner which mixes combustion air and fuel by a swirling blade body to generate an air-mixed fuel, and burns the generated air-mixed fuel. The present invention relates to a heat source device such as a boiler provided with a mold premix burner.

[0002]

2. Description of the Related Art As a swirling type premix burner used for a heat source device such as a boiler, there is known, for example, one disclosed in Japanese Patent Application Laid-Open No. Hei 6-101815. This known premix burner includes a cylindrical burner main body, a fuel injection nozzle is disposed inside the burner main body, and a swirling blade body is rotatably supported around the fuel injection nozzle as a central axis. Further, a flame holding member is disposed on the burner top side of the burner main body. In this swirling type premix burner, combustion air is supplied through the burner main body, and fuel, for example, fuel gas is ejected from the fuel injection nozzle into the airflow thus flowing. The fuel air and the ejected fuel flow through the swirl vanes, and when they flow, they are mixed by the action of the swirl vanes, and the air-mixed fuel mixed with the air is ejected from the burner outlet of the burner body and burned. I do. During this combustion,
Since the air-mixed fuel ejected from the burner body flows radially outside the flame holding member, a circulating flow of combustion gas is generated in a downstream region of the flame holding member, and the circulating flow of the combustion gas is ignited. As a source, stable combustion of the air-mixed fuel is performed.

[0003]

However, in this type of swirl type premixed burner, when the combustion load increases, in other words, when the supply amount of the air-mixed fuel increases, the flow rate of the air-mixed fuel flowing through the burner main body increases. And the flame holding by the flame holding member becomes unstable. If the flame holding becomes unstable in this way, the air-mixed fuel will burn incompletely, and carbon monoxide will be generated. An object of the present invention is to provide a swirl-type premix burner that can stabilize flame holding and suppress generation of carbon monoxide.

It is another object of the present invention to provide a heat source unit capable of suppressing the generation of carbon monoxide during combustion.

[0005]

According to the present invention, there is provided a cylindrical burner main body, an injection nozzle for ejecting fuel into the burner main body, and disposed inside the burner main body and flowing through the burner main body. A swirling blade including a swirling blade body for mixing combustion air and fuel ejected from the injection nozzle to generate an air-mixed fuel, and a flame holding member disposed on a burner top side of the burner body. A mold premix burner, wherein the flame holding member is provided at a central flame holding portion disposed at a radial center portion of the burner main body, and is provided at intervals in a circumferential direction of the central flame holding portion; It is characterized by comprising a central flame holding portion and a plurality of connection flame holding portions for connecting a tip portion of the burner main body.

According to the present invention, a flame holding member is disposed on the burner top side of the burner main body, and the flame holding member is provided at a distance from the center flame holding portion in the circumferential direction of the central flame holding portion. And a connected flame holding section. Therefore, a circulating flow of the combustion gas is generated downstream of the central flame holding section and the connection flame holding section, and flame holding can be performed in a wide area while securing a flow path for the air-mixed fuel. Therefore, flame holding by the flame holding member is stabilized, and generation of carbon monoxide can be suppressed even when the combustion load increases. In addition, as a fuel, a fuel gas, a fuel oil, or the like can be used.

In the present invention, a plurality of flame holding holes are provided in the central flame holding portion of the flame holding member. According to the present invention, since a plurality of flame holding holes are provided in the central flame holding portion, a part of the air-mixed fuel ejected from the burner body flows through these flame holding holes and passes through the flame holding holes. Its flow rate drops sharply. Therefore, the flame holding of the combustion gas is performed in these flame holding holes, and therefore, the flame holding is performed in almost the entire central flame holding portion, and the flame holding by the flame holding member can be further stabilized.

In the present invention, the plurality of connection flame holding portions of the flame holding member are provided with a plurality of flame holding holes, respectively. According to the present invention, since a plurality of flame holding holes are provided in the plurality of connection flame holding portions, a part of the air-mixed fuel ejected from the burner body flows through the flame holding holes of the connection flame holding portion, After passing through the flame holding hole, the flow velocity sharply decreases. Therefore, the flame holding of the combustion gas is performed in the flame holding holes of each of the connecting flame holding sections. Therefore, the flame holding is performed on almost all of the plurality of connecting flame holding sections, and the flame holding by the flame holding member is further enhanced. Can be stabilized.

Further, in the present invention, the flame holding member further includes a plurality of arc-shaped flame holding portions for connecting radially outer ends of the plurality of connection flame holding portions, and the plurality of arc-shaped flame holding portions. A plurality of flame holding holes are provided in the flame holding section. According to the present invention, the flame holding member further has a plurality of arc-shaped flame holding portions, and the arc-shaped flame holding portion also has a plurality of flame holding holes. A circulating flow of combustion gas is generated at the, and flame holding can be performed by this circulating flow, and a part of the air-mixed fuel ejected from the burner main body also passes through the flame holding holes of the plurality of arc-shaped flame holding portions. The flames of the combustion gas are also held in these flame holding holes, and thus the flame holding is performed in a wide area extending over the central flame holding section, the plurality of connecting flame holding sections, and the plurality of arc-shaped flame holding sections. Flame holding by the flame member can be further stabilized.

[0010] In the present invention, the plurality of connection flame holding portions may be configured such that air is provided radially inward from one end connected to the burner body to the other end connected to the central flame holding portion. It is characterized in that it extends linearly downstream in the flow direction of the mixed fuel. According to the present invention, the plurality of connection flame holding portions of the flame holding member extend downstream in the flow direction of the air-mixed fuel toward the radially inner central flame holding portion, and the air mixing flow flowing through the burner body. The fuel flows spirally by the action of the swirling blade body and flows downstream. For this reason, the air-mixed fuel ejected from the burner main body flows downstream in a radially expanding manner, whereby the combustion gas is also generated so as to radially expand in the radially outward direction. Since the combustion gas spreads in this manner, the combustion temperature of the combustion gas decreases due to the ambient temperature, whereby the generation of nitrogen oxides (NOx) can be suppressed.

Further, the present invention provides a cylindrical burner main body, an injection nozzle for jetting fuel into the burner main body,
A swirling vane disposed in the burner main body for mixing combustion air flowing in the burner main body and fuel ejected from the injection nozzle to generate an air-mixed fuel; and a burner top of the burner main body. A flame holding member disposed on the side, and a revolving type premix burner comprising: a flame holding member having a central flame holding portion disposed at a radially central portion of the burner body; The central flame holding portion is provided with a plurality of flame holding holes.

According to the present invention, a flame holding member is disposed on the burner top side of the burner main body, the flame holding member has a central flame holding portion, and the central flame holding portion has a plurality of flame holding holes. Is provided. Therefore, a circulating flow of the combustion gas is generated downstream of the central flame holding portion, and the flame can be held by the circulating flow. In addition, a part of the air-fuel mixture ejected from the burner main body flows through the flame holding holes of the central flame holding portion, and after passing through the flame holding holes, the flow velocity drops sharply. Flames are performed. Thus, flame holding is performed in substantially the entire central flame holding portion, and the flame holding by the flame holding member can be stabilized.

Further, the present invention provides a heat source device main body, a plurality of hollow pipes disposed in a heat exchange area in the heat source device main body, through which a liquid to be heated flows, and a combustion chamber in the heat source device main body. A swirl type premix burner according to any one of claims 1 to 6, wherein heat exchange is performed between combustion exhaust gas from the swirl type premix burner and liquid flowing through the plurality of hollow pipes. Is performed. According to the present invention, since the premix burner according to claims 1 to 7 is provided, it is possible to improve the flame holding performance of the burner as described above, thereby preventing the occurrence of incomplete combustion, Generation of carbon monoxide can be suppressed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the accompanying drawings, embodiments of a swirling type premix burner according to the present invention and a boiler as an example of a heat source device provided with the same will be described below. FIG.
1 is a sectional view schematically showing an embodiment of a boiler as an example of a heat source unit according to the present invention, and FIG. 2 is a premix burner (one embodiment of a premix burner according to the present invention) mounted on the boiler of FIG. FIG. 3 is a side view of the premix burner of FIG. 2 as viewed from the burner top side.

In FIG. 1, a boiler as an example of a heat source unit shown in the drawing includes a cylindrical boiler main body 2 as a sealed heat source unit main body, and an upper end and a lower end of the boiler main body 2 are provided with a fire-resistant supporting member 4. , 6 are arranged, and a hollow pipe 8 constituting a water pipe is supported between the support members 4, 6. A plurality of hollow pipes 8 are disposed radially inward of the peripheral side wall 10 of the boiler main body 2 at circumferential intervals with one end thereof penetrating through the support member 4 and protruding upward. The other end of the portion is connected to the upper connection pipe 12, and the other end thereof penetrates the other support member 6 and protrudes below the other support member 6, and the lower protruding end is connected to the lower connection pipe 14. The lower connection pipe 14 is connected, for example, to a water supply source (not shown) such as a water pipe via a supply pipe 16, and the upper connection pipe 12 is connected to a heat load (such as a heating device) via a discharge pipe 18. (Not shown).

With this configuration, the water from the water supply source is supplied as indicated by an arrow 20 and flows through the plurality of hollow pipes 8 through the supply pipe 16 and the lower connection pipe 14.
While flowing through the hollow pipe 8, it is heated by heat exchange as described below. Heated hot water (or steam)
Flows into the upper connection pipe 12 and is discharged through the discharge pipe 18 toward the heat load as indicated by the arrow 22. In this embodiment, a swirling type premix burner 24 is provided at the upper end of the boiler main body 2. The premix burner 24 includes a burner main body 26, and the burner main body 26 is attached to a substantially central portion of an upper end portion of the boiler main body 2. Air-mixed fuel (a mixture of combustion air and fuel) is ejected from a burner outlet 28 (see FIG. 2) of the burner main body 26, and the ejected air-mixed fuel is burned. As the fuel, for example, fuel gas such as city gas and LP gas, fuel oil and the like are used. The revolving type premix burner 24 will be described later in detail.

A combustion chamber 28 is provided in the center of the burner body 2 in the radial direction, and a heat exchange area 30 is provided annularly outside of the combustion chamber 28 in the radial direction. The premix burner 24 is disposed in the combustion chamber 28. A plurality of hollow pipes 8 are disposed in the heat exchange area 30 in a ring shape. An exhaust pipe 32 is connected to an upper portion of the boiler main body 2. In this boiler, the air-mixed fuel injected from the premix burner 24 burns in the combustion chamber 28, and the combustion exhaust gas is transferred to the heat exchange zone 30.
Flows through the exhaust pipe 32 in the direction indicated by the arrow 34 and is discharged to the outside. In the heat exchange area 30, heat exchange is performed between water flowing in the hollow pipe 8 and combustion exhaust gas flowing in the heat exchange area 30, and heated water (or steam) is subjected to a heat load (see FIG. (Not shown).

Next, the swirl type premix burner 24 will be described with reference to FIG. 1 and FIG. 2. The burner main body 26 of the illustrated premix burner 24 is cylindrical, and the first cylinders connected to each other are connected to each other. And a second cylindrical member 38. One end of the first tubular member 36 is sealed by an end plate 40, and the second tubular member 3 is attached to the other end.
8 is connected to one end. An air supply port 42 is provided on a peripheral side surface of the first cylindrical member 36, and combustion air from an air supply source such as a compressor is supplied through the air supply port 42 as shown by an arrow 44.

A fuel injection nozzle 46 is provided in the burner main body 26.
Are arranged. The fuel injection nozzle 46 is composed of an elongated pipe member, one end of which is formed by an end plate 40.
And projecting outward through the sealing member 48 at the other end.
Is installed. The fuel injection nozzle 46 extends from one end supported by the end plate 40 to the vicinity of the other end of the second cylindrical member 38 through the first cylindrical member 36. The base of the fuel injection nozzle 46, in this embodiment, the first cylindrical member 3
A plurality of injection holes 50 are provided at a position opposing the air supply port 42 and in the vicinity thereof at intervals in the axial direction (the left-right direction in FIG. 2) and the circumferential direction. A fuel supply pipe 52 is connected to an end of the fuel injection nozzle 46 protruding from the end plate 40, and a fuel gas from a fuel supply source (not shown) such as a gas buried pipe or a gas cylinder is indicated by an arrow 54. As shown, the fuel is supplied to the fuel injection nozzle 46 through the fuel supply pipe 52, and the burner body 4 is supplied through the injection hole 50.
6 is injected.

In the burner body 46, in this embodiment, an arrow 56
A swirl vane 58 is disposed downstream of the air supply port 42 and the injection hole 50 when viewed in the flow direction of the air-mixed fuel, and the swirl vane 58 is rotatably supported by the tip of the fuel injection nozzle 46. Have been. The swirling blade body 58 includes a plurality of blades, and swirls in a predetermined direction by flowing combustion air and fuel downstream as indicated by an arrow 56. When the swirling blade body 58 is swirled in this manner, the flow of combustion air and fuel flows downstream as a swirling flow as shown by the solid line arrow in FIG. 2, and the premixing of fuel air and fuel is promoted. Thus, the premixed air-mixed fuel is ejected from the burner outlet 28 of the burner main body 26.

In this premix burner 24, the burner main body 2
A flame-holding member 60 for flame-holding the combustion gas is provided on the front end side of the burner 6, that is, on the burner top side. Referring to FIG. 3 as well, the illustrated flame holding member 60 is formed of a plate-like member, and has a circular center flame holding portion 62 disposed at a radially central portion of the cylindrical burner main body 26 and a central flame holding member 62. Flame 62
A plurality of connection flame stabilizers 6 arranged at intervals in the circumferential direction
4 (in this embodiment, six are provided at intervals of substantially 60 degrees). Each connection flame holding portion 62 has a fan shape whose circumferential width increases radially outward,
The inner peripheral end is fixed to the central flame holding portion 62, and the outer peripheral end is fixed to the tip of the burner main body 26. By providing the central flame holding section 62 and the connection flame holding section 64 in this manner, the flow of the combustion gas to the downstream side is reduced by the central flame holding section 6.
2 and the connection flame stabilizing portion 64, whereby a circulating flow of the combustion gas is generated downstream thereof, and the circulating flow causes the flame holding of the combustion gas in the central flame stabilizing portion 62 and the connection flame stabilizing portion 64. Will be Since the flame holding is performed in a wide range of the central flame holding portion 62 and the connection flame holding portion 64, the flame holding is stabilized, whereby the incomplete combustion of the air-mixed fuel can be prevented, and the monoxide can be prevented. The generation of carbon can be suppressed.

In this embodiment, the flame holding member 60 further has an arc-shaped flame holding portion 66 provided between outer peripheral ends of the plurality of connection flame holding portions 64. One end of each arc-shaped flame holding portion 66 is fixed to one of the adjacent connection flame holding portions 64, and the other end is fixed to the other of the adjacent flame holding portions 66. Is fixed to the part.
By providing the arc-shaped flame holding portion 66 in this way, the flow of the combustion gas to the downstream side is also hindered by the arc-shaped flame holding portion 66, whereby the circulating flow of the combustion gas is generated at the downstream side, and the arc-shaped flame holding portion is formed. The flame holding of the combustion gas is also performed in the flame holding section 66, and the flame holding can be further stabilized. In particular, in the above-mentioned swirling type premix burner 24, since the combustion gas from the burner main body 26 spirally spreads, the flow velocity of the combustion gas becomes higher toward the outer periphery thereof, and the flame holding of the combustion gas becomes difficult. The provision of the arc-shaped flame holding portion 66 facilitates the flame holding and further stabilizes the flame holding of the combustion gas.

In this embodiment, a plurality of flame holding holes 68, 70, 72 are provided in the central flame holding portion 62, the connection flame holding portion 64, and the arc-shaped flame holding portion 66 of the flame holding member 60. By providing the flame holding holes 68, 70, 72 in this way, a part of the air-mixed fuel ejected from the burner outlet 28 of the burner body 26 flows through these flame holding holes 68, 70, 72, After passing through the flame holding holes 68, 70, 72, the flow velocity sharply decreases. Therefore, these flame holding holes 6
The flame holding of the combustion gas is carried out at 8, 70 and 72, and the flame holding holes 68, 70 and 72 are formed substantially in the central flame holding portion 62, the connection flame holding portion 64 and the arc-shaped flame holding portion 66 as shown in FIG. By providing it in the entire area, flame holding is performed in almost all of these areas, and stable flame holding can be performed in a wide area.

The flame holding holes 68, 70, 72 are formed, for example, in a circular shape, and have a size of 0.5 to 10 mm in diameter, preferably 1 to 5 mm. Each flame holding hole 68,7
If the diameter of 0,72 is less than 0.5 mm, the amount of the air-mixed fuel passing therethrough will be small, the combustion in the flame holding holes 68, 70, 72 will be small, and stable flame holding of the combustion gas will be difficult. Further, the diameter of each flame holding hole 68, 70, 72 is 10
If it exceeds mm, the passage amount of the air-mixed fuel increases, and even after passing through the flame holding holes 68, 70, 72, a decrease in the flow velocity of the air-mixed fuel is small, and stable flame holding of the combustion gas becomes difficult.

In the above-described embodiment, the central flame holding section 6
2. Flame holding holes 68 in the connection flame holding portion 64 and the arc-shaped flame holding portion 66;
70 and 72 are provided.
It is not necessary to provide the flame holding holes in any one or two of the flame holding portions 62, 64, 66, and the above-described desired effects can be achieved. In this premix burner 24, as shown in FIG. 2, each connection flame holding portion 64 of the flame holding member 60 extends from an end connected to the burner main body 26 to an end connected to the central flame holding portion 60. The flame-holding member 60 extends linearly inward in the radial direction and downstream in the flow direction of the air-mixed fuel, and is formed in a truncated cone shape as a whole. By configuring the flame holding member 60 in this way, it is possible to increase the area of the entire flame holding member 60 while securing a predetermined opening ratio of the burner main body 26, and thereby, on the downstream side of the flame holding member 60. The flame stabilizing effect can be enhanced by reducing the flow rate of the combustion gas.
Further, the air-mixed fuel spouted from the spout 28 of the burner body 26 is spouted radially outward as shown by an arrow 74 in FIG. 2, whereby the combustion gas is also spouted radially outward. Spreads radially. Thus, the combustion gas is cooled by the air around the combustion chamber 28 of the boiler main body 2, and the combustion temperature of the combustion gas is reduced, whereby the generation of nitrogen oxides can be suppressed.

Next, the operation of the above-described boiler will be described. In order to generate hot water (or steam) by the boiler, water may be flown through the hollow pipe 8 in the boiler body 2 and the air-mixed fuel may be burned by the premix burner 24. In the premix burner 24, combustion air is supplied into the burner main body 26 through the air supply port 42, and fuel (for example, fuel gas) is injected into the burner main body 26 from the injection hole 50 of the injection nozzle 46. The combustion air and fuel flow in the flow direction indicated by arrow 56.
The combustion air and the fuel thus flowing are mixed by the swirling blade body 58, and flow further downstream as a swirling flow. Then, the fuel is ejected from the burner outlet 28 of the burner main body 26 and burned to generate combustion gas, and the combustion exhaust gas is discharged outside through the heat exchange area 30 and the exhaust pipe 30.

In this boiler, since the above-described flame holding member 60 is provided on the burner top side of the burner main body 26, the flame holding by the flame holding member 60 is stabilized, whereby the air blown out from the burner main body 26 is provided. The mixed fuel is completely burned, and the generation of carbon monoxide during combustion can be suppressed. Further, since the flame holding member 60 is configured as described above, the combustion gas from the burner main body 26 spreads radially outward to the heat exchange region 30 as shown in FIG. Thus, the hollow pipe 8 is efficiently heated by the combustion exhaust gas, and as a result, hot water (or steam) can be efficiently generated. Further, when the combustion gas spreads radially in this manner, the combustion gas is cooled by the air around the combustion chamber 28, and the combustion temperature is reduced, so that generation of nitrogen oxides can be suppressed.

In the above-described embodiment, the central flame holding portion 62 and the burner main body 26 are connected by the six connection flame holding portions 64, but the number of the connection flame holding portions 64 can be set as appropriate. For example, about 4 to 8 pieces can be provided. In the above-described embodiment, although not particularly provided, in order to enhance the flame holding ability, for example, the burner main body 26 is used.
In the radial direction of the central flame holding portion 62 and the arc-shaped flame holding portion 66
And an intermediate arc-shaped flame-holding portion may be provided between them, and if necessary, a plurality of flame-holding holes may be provided in the intermediate arc-shaped flame-holding portion.

Further, in the illustrated embodiment, the flame holding holes are formed in a circular shape.
It can be formed in an appropriate shape such as a semicircle, a square, a sector, a slit, or the like. In the illustrated embodiment, the present invention is applied to a boiler as an example of a heat source unit. However, the present invention is not limited to this, and a regenerator (absorber liquid) of an absorption refrigerator as another example of a heat source unit is used. A regenerator for heating) can be similarly applied.

Examples and Comparative Examples In order to confirm the effect of the swirling type premix burner having the above-described configuration, the following combustion experiment was performed. As Example 1,
Using a premix burner of the form shown in FIGS. 2 and 3, city gas was burned as fuel, and the concentration of carbon monoxide (CO) contained in the combustion exhaust gas when the combustion load was changed was measured. The air ratio at the time of combustion was 1.2, and the dimensions of each part of the premix burner used were as follows.

The inner diameter of the burner body 170 mm The outer diameter of the combustion injection nozzle 30 mm The number of injection holes of the combustion injection nozzle 6 The inner diameter of the injection hole 3 mm The outer diameter of the central flame holding section for the flame holding member 30 mm The number of connection flame holding sections 6 Circumferential angle of connecting flame holding part 15 degrees Width of arc-shaped flame holding part 10mm Number of flame holding holes of central flame holding part 19 Number of flame holding holes of each connecting flame holding part 16 Number of flame holding holes of arc-shaped flame holding part 7 Individual Diameter of flame holding hole 3 mm Inclination angle of connection flame holding part (inclination angle with respect to radial surface) 30 degrees The concentration of carbon monoxide during combustion of the premixed burner of Example 1 is as shown in graph A of FIG. And the amount of combustion is 100
Up to kW, the concentration of carbon monoxide was about 60 ppm or less, and when the amount of combustion exceeded 100 kW, this concentration sharply increased.

Further, as a second embodiment, a premix burner substantially the same as the first embodiment except that the connection flame holding portion of the flame holding member extends inward in the radial direction without being inclined, and city gas is used as fuel. The combustion was performed at an air ratio of 1.2, and the concentration of carbon monoxide contained in the combustion exhaust gas when the combustion load was changed was measured. The concentration of carbon monoxide at the time of combustion of the premixed burner of Example 2 is as shown by the graph B in FIG. 4, and the concentration of carbon monoxide is about 60 ppm up to a combustion amount of 90 kW.
When the combustion amount exceeded 90 kW, the concentration increased sharply.

As Comparative Example 1, a premix burner substantially the same as that of Example 1 except that the flame holding member had only a central flame holding portion (outer diameter: 50 mm) was used. 2, and the concentration of carbon monoxide contained in the combustion exhaust gas when the combustion load was changed was measured. The concentration of carbon monoxide during combustion of the premixed burner of Comparative Example 1 is as shown in graph C of FIG.
Up to W, the concentration of carbon monoxide is about 60 ppm or less, but when the combustion amount exceeds 50 kW, this concentration sharply increases.

From the above experimental results, the premixed burners of Examples 1 and 2 generate less carbon monoxide than those of Comparative Example 1 even when the fuel load increases, and the combustion of the air mixed gas is reduced. It was confirmed that it was stable. This is because in Examples 1 and 2, the flame holding ability by the flame holding member is high,
It is considered that the flame holding of the combustion gas is stabilized, thereby stabilizing the combustion of the air mixed gas. Next, as Example 3, using the same premix burner as in Example 1, burning city gas as fuel, fixing the amount of combustion, and supplying the amount of combustion air (ie, the residual oxygen concentration in the combustion exhaust gas) ) And nitrogen oxides (NOx) contained in the combustion exhaust gas
Was measured. The combustion amount at this time was 115 kW. The nitrogen oxide concentration at the time of combustion of the premix burner of Example 3 was as shown in the graph D of FIG.

As Comparative Example 2, using the same premix burner as in Comparative Example 1, the concentration of nitrogen oxides contained in the combustion exhaust gas when city gas was burned was measured in the same manner as in Example 3. The nitrogen oxide concentration at the time of combustion of the premix burner of Comparative Example 2 was as shown by the graph E in FIG. From the results described above, it was confirmed that in Example 3, the concentration of nitrogen oxide was about １ ／ to １ ／ as compared with Comparative Example 2, and the emission amount of nitrogen oxide was significantly reduced. . This is presumably because in the case of the third embodiment, the combustion gas spreads radially, thereby suppressing an increase in the combustion temperature of the combustion gas.

[0036]

According to the premix burner of the first aspect of the present invention, the flame holding member provided on the burner top side of the burner main body has a central flame holding section and a connection flame holding section. Therefore, a circulating flow of the combustion gas is generated downstream of the central flame holding section and the connection flame holding section, and the flame holding of the combustion gas can be performed in these flame holding sections, and the flame holding can be stabilized. .

According to the premixed burner of the second aspect of the present invention, since a plurality of flame holding holes are provided in the central flame holding portion of the flame holding member, the air mixed fuel injected from the burner main body is provided. A part flows through these flame holding holes, and the flame holding of the combustion gas can be performed also in the flame holding hole of the central flame holding section. Further, according to the premix burner of claim 3 of the present invention, since a plurality of flame holding holes are provided in the plurality of connection flame holding portions,
A part of the air-mixed fuel ejected from the burner main body flows through the flame holding holes of the connection flame holding sections, and the flame of the combustion gas can also be held in the flame holding holes of each connection flame holding section.

Further, according to the premix burner of the present invention, the flame holding member further has a plurality of arc-shaped flame holding portions, and the arc-shaped flame holding portion also has a plurality of flame holding holes. The flame holding can be performed by the circulating flow of the combustion gas generated downstream of the arc-shaped flame holding portion, and the flame holding can also be performed by combustion with the air-mixed fuel passing through the flame holding hole of the arc-shaped flame holding portion. Is performed, and the flame holding by the flame holding member can be further stabilized. According to the premix burner of claim 5 of the present invention, since the plurality of connection flame holding portions of the flame holding member extend in a predetermined direction, the combustion gas from the burner body is radially outward. Is generated so that the combustion temperature of the combustion gas decreases due to the ambient temperature,
Generation of nitrogen oxides can be suppressed.

According to the premix burner of the present invention, the flame holding member provided on the burner top side of the burner main body has a central flame holding portion. Since the flame holding holes are provided, the flame holding can be performed by the circulating flow of the combustion gas generated on the downstream side of the central flame holding portion, and the flame holding is performed by the combustion of the air-mixed fuel passing through the flame holding holes. The flame holding by the flame holding member can be stabilized. Furthermore, according to the heat source device of claim 7 of the present invention, since the premix burner according to claims 1 to 7 is provided, the flame holding performance of the burner can be improved as described above, Prevent the occurrence of incomplete combustion,
Generation of carbon monoxide can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing an embodiment of a boiler as an example of a heat source device according to the present invention.

FIG. 2 is a sectional view showing a premix burner provided in the boiler of FIG. 1;

FIG. 3 is a side view of the premix burner of FIG. 2 as viewed from a burner top side.

FIG. 4 is a diagram showing the relationship between the amount of combustion and the concentration of carbon monoxide contained in the combustion exhaust gas.

FIG. 5 is a diagram showing the relationship between the concentration of residual oxygen in flue gas and nitrogen oxides in flue gas.

[Explanation of symbols]

 2 Boiler Body 8 Hollow Pipe (Water Pipe) 24 Swirling Premix Burner 26 Burner Body 28 Combustion Chamber 30 Heat Exchange Area 46 Fuel Injection Nozzle 50 Injection Hole 58 Swirling Blade Body 60 Flame Retention Member 62 Central Flame Retention Section 64 Connection Flame Retention Section 66 arc-shaped flame holding part 68, 70, 72 flame holding hole

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Akira Miyato 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi F-term in Osaka Gas Co., Ltd. (reference) 3K017 AA01 AA02 AA06 AB07 AC06 AD10 AD14 3K055 AA10 BA07 BA11 BC02 BC04 BC10 CA03

Claims (7)

[Claims] 1. A cylindrical burner main body, an injection nozzle for injecting fuel into the burner main body, and a combustion air provided in the burner main body and flowing through the burner main body and the injection nozzle. A swirling-type premix burner comprising: a swirling blade body for mixing the ejected fuel to generate an air-mixed fuel; and a flame holding member disposed on a burner top side of the burner main body. The flame holding member is provided at a central flame holding portion disposed at a radially central portion of the burner main body and at intervals in a circumferential direction of the central flame holding portion, and the central flame holding portion and the burner main body are provided. And a plurality of connection flame holding portions for connecting the leading end portions of the revolving type premix burner. 2. The flame stabilizing member according to claim 1, wherein the flame stabilizing member has a plurality of flame stabilizing holes in the central flame stabilizing portion.
The swirl-type premix burner as described. 3. The swirling type premix according to claim 1, wherein a plurality of flame holding holes are provided in each of the plurality of connection flame holding portions of the flame holding member. Burner. 4. The flame holding member further includes a plurality of arc-shaped flame holding portions connecting radially outer ends of the plurality of connection flame-holding portions. The swirling type premix burner according to any one of claims 1 to 3, wherein a plurality of flame holding holes are provided. 5. The flow of the air-mixed fuel radially inward from one end connected to the burner body to the other end connected to the central flame holding portion, wherein the plurality of connection flame holding portions are provided. The swirling-type premix burner according to any one of claims 1 to 4, wherein the swirl-type premix burner extends linearly downstream in the direction. 6. A burner main body having a cylindrical shape, an injection nozzle for injecting fuel into the burner main body, a combustion air provided in the burner main body and flowing through the burner main body and the injection nozzle. A swirling-type premix burner comprising: a swirling blade body for mixing the ejected fuel to generate an air-mixed fuel; and a flame holding member disposed on a burner top side of the burner main body. The flame stabilizing member has a central flame stabilizing portion disposed at a radial center portion of the burner main body, and the central flame stabilizing portion is provided with a plurality of flame stabilizing holes. Mold premix burner. 7. A heat source device main body, a plurality of hollow pipes disposed in a heat exchange area in the heat source device main body, through which a liquid to be heated flows, and disposed in a combustion chamber in the heat source device main body. A swirling type premix burner according to any one of claims 1 to 6,
A heat source device wherein heat exchange is performed between combustion exhaust gas from the swirling type premix burner and liquid flowing through the plurality of hollow pipes.