JP2010133664A - Burner tip structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a burner tip structure capable of securing a sufficient mixing distance in a mixing section flow channel in which an atomizing medium flows, without increasing a dimension of the shape of a burner tip body, and increasing the consumption of the atomizing medium such as steam. <P>SOLUTION: In this two-fluid type burner tip structure in which fuel oil is atomized by the steam in the burner tip body 10 and charged into a furnace, the inside of a steam main flow channel 11 has a two stage structure having a downstream side end section inclined face 11a and a step section inclined face 11b, an outlet opening of the mixing section flow channel 12A formed in a state of communicated with the downstream side end section inclined surface 11a of the steam main flow channel 11, is composed of a narrow angle injection hole 15A, and an outlet opening of the mixing section flow channel 12B formed in a state of communicated with the step section inclined surface 11b is composed of a wide angle injection hole 15B. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a burner tip structure applied to an oil-fired boiler or the like.

Conventionally, in an oil-fired boiler, a two-fluid chip is used as a burner chip structure.
The two-fluid burner chip structure is well known for establishing ignition and combustion by using air or steam as a spray medium and atomizing oil (including poor fuels such as asphalt and VR) as fuel. It has been. In such a two-fluid burner tip structure, fuel oil and steam are mixed in a mixing section in the tip, and are injected into the furnace while being atomized.

The burner tip structure shown in FIGS. 3 and 4 includes a plurality of (eight in the illustrated configuration example) ejection holes in which the ejection direction of the atomized fuel is unbalanced to a wide angle and a narrow angle in order to improve combustibility. It is a thing.
In the illustrated burner tip structure, a steam main passage 2 for supplying steam as a spray medium is formed in the center of the upstream side inside the burner tip body 1. The steam main flow path 2 is formed up to a substantially intermediate position in the axial direction of the burner tip body 1, and is branched from the tip 2a and the middle of the flow path, and a plurality of divided steam flow paths 3A and 3B are formed radially outward. Has been. The divided steam flow paths 3A and 3B are in communication with a plurality of mixing section flow paths 4A and 4B provided so as to open to the front end portion 1a or the side surface portion 1b of the burner tip body 1, respectively. The number of the mixing section channels 4A and 4B is the same as that of the divided steam channels 3A and 3B, and the channel cross-sectional area is expanded from the divided steam channels 3A and 3B on the same axis.

The same number (plural) of fuel oil passages 5A and 5B as the mixing section passages 4A and 4B are formed on the outer peripheral side of the steam main passage 2 so as to have an equal pitch in the circumferential direction of the burner tip body 1. Has been placed. The fuel oil passages 5A and 5B supply fuel oil as fuel for the oil-fired boiler. Inside the burner chip body 1, the mixing section passages 4A and 4B are separated from the divided steam passages 3A and 3B. It joins from the side surface or an oblique direction to the side surface in the vicinity of the communicating inlet.
A back plate (not shown) that rectifies steam and fuel oil and switches the flow path is connected to the upstream side of the burner chip body 1.

  In the two-fluid burner tip structure configured as described above, the vapor of the spray medium which is diverted from the main steam flow path 2 and flows through the divided steam flow paths 3A and 3B and the fuel oil flow paths 5A and 5B is supplied. The fuel oil thus formed joins in the mixing section flow paths 4A and 4B, so that the fuel oil is atomized by collision at the time of joining and agitation / mixing when flowing in the mixing sections 4A and 4B. Then, the fuel oil atomized through the mixing section flow paths 4A and 4B is introduced into the furnace together with the steam from the outlet opening of the mixing sections 4A and 4B opening in the burner tip body 1 as the atomized fuel.

  The outlet opening in this case is a narrow-angle jet hole 6A in which the outlet opening of the mixing section flow path 4A that opens to the tip portion 1a of the burner tip body 1 is reduced in the injection angle of the atomized fuel toward the inside of the furnace, The outlet opening of the mixing section flow path 4B that opens to the side surface portion 1b of the burner tip body 1 is a wide-angle jet hole 6B that increases the injection angle of the atomized fuel toward the furnace. Note that the atomization fuel is supplied at an angle of 0 degrees with respect to the axis of the burner tip body 1.

As another conventional technique related to the two-fluid burner tip structure, by adding a steam flow path opened at the tip of the burner tip, fuel atomization is promoted to improve the spray performance, and nitrogen oxide In addition, a burner that can suppress the generation of smoke is proposed. (For example, see Patent Document 1)
As another conventional technique related to the two-fluid burner tip structure, there has been proposed a slurry fuel atomizer structure that finely atomizes (sprays) slurry fuel such as CWM (high concentration coal / water slurry) for boiler equipment. ing. In this prior art, the atomizing medium supply annular flow path is converged on the tip side to accelerate the atomizing medium and then merge with the slurry fuel. (For example, see Patent Document 2)

JP 2002-168413 A JP-A-9-287714

  By the way, the above-described two-fluid burner tip structure needs to ensure sufficient mixing distances L1 and L2 for the channel length of the mixing section channels 4A and 4B in order to ensure good atomization and combustibility. is there. As for the mixing distances L1 and L2 of the general mixing section flow paths 4A and 4B, when the mixing section flow paths 4A and 4B and the outlet diameters of the mixing section flow paths 4A and 4B are D1 and D2, the flow path diameters D1 and D2 are 2-3. It is necessary to ensure at least twice (L1 / D1> 2 to 3, L2 / D2> 2 to 3). The mixing distances L1 and L2 are the channel lengths from the position where the fuel oil and the steam merge to the channel outlet.

However, in the case of improving the combustibility by unbalancing the injection direction of the atomized fuel as in the narrow-angle injection hole 6A and the wide-angle injection hole 6B described above, the mixing on the wide-angle injection hole 6B side having a wide injection angle is performed. The distance L2 tends to be shorter.
The burner tip body 1 is generally designed to increase the flow path diameters D1 and D2 in order to increase the steam consumption rate as the burner combustion amount increases. Accordingly, there is a concern that sufficient mixing distances L1 and L2 cannot be ensured due to the size and shape restrictions that the burner tip body 1 receives, resulting in a two-fluid burner tip structure that does not provide good atomization. Furthermore, if the outer diameter of the burner tip body 1 is increased and the flow path diameters D1 and D2 are enlarged, the structure of the entire burner such as a burner flame stabilizer is not preferable.

From such a background, in the burner tip structure that improves the combustibility by unbalance the jet direction of the atomized fuel, the shape of the burner tip body is changed when the spray medium consumption rate is increased as the burner combustion amount increases. It is desired to develop a burner tip structure that can secure a sufficient mixing distance without increasing the size.
The present invention has been made in view of the above circumstances, and the object of the present invention is, in particular, the shape of the burner tip body in the burner tip structure for improving the combustibility by unbalance the ejection direction of the atomized fuel. An object of the present invention is to provide a burner tip structure capable of ensuring a sufficient mixing distance in a mixing section flow path for flowing a spray medium without increasing the size and increasing the consumption of a spray medium such as steam.

In order to solve the above problems, the present invention employs the following means.
The burner tip structure according to the present invention is a two-fluid burner tip structure in which fuel oil is atomized by a spray medium in a burner tip body and is injected into a furnace, and is formed upstream of the axial center position of the burner tip body. The spray medium main flow path, a plurality of mixing section flow paths formed radially outwardly from the spray medium main flow path, and the vicinity of the inlet of the mixing section flow path formed on the outer periphery of the spray medium main flow path A plurality of fuel oil passages that merge with the side surfaces and that have inlet openings arranged at equal pitches in the circumferential direction, and the inside of the spray medium main passage forms a downstream end inclined surface and a stepped portion inclined surface It has a two-stage structure, and the outlet opening of the mixing section flow path formed in communication with the inclined surface on the downstream end of the spray medium flow path is a narrow-angle jet hole, and the step portion of the spray medium flow path Formed in communication with the inclined surface It is characterized in that the outlet opening of the serial mixing zone passage was wide ejection hole.

  According to such a burner tip structure, the spray medium main channel formed on the upstream side of the axial center position of the burner tip main body, and a plurality of mixed section flows formed by branching radially outward from the spray medium main channel. And a plurality of fuel oil passages formed on the outer periphery of the spray medium main flow passage and joined to the side surface in the vicinity of the inlet of the mixing section flow passage, and the inlet openings are arranged at equal pitches in the circumferential direction. The inside of the main flow path has a two-stage structure in which a downstream end inclined surface and a stepped portion inclined surface are formed, and the mixing section flow path formed in communication with the downstream end inclined surface of the spray medium flow path Since the outlet opening is a narrow-angle ejection hole and the outlet opening of the mixing section channel formed in communication with the inclined surface of the step portion of the spray medium channel is a wide-angle ejection hole, the size and shape of the burner tip body Enough mixing distance without increasing the size It can be.

  The burner tip structure of the present invention is a two-fluid burner tip structure in which fuel oil is atomized by a spray medium in a burner tip body and is introduced into a furnace, and is formed upstream of the axial center position of the burner tip body. A spray medium main channel, a plurality of mixing section channels formed by branching radially outward from the spray medium main channel, and a side surface near the inlet of the mixing section channel formed on the outer periphery of the spray medium main channel And a plurality of fuel oil passages whose inlet openings are arranged at equal pitches in the circumferential direction, and the inside of the spray medium main passage forms a downstream end inclined surface and a stepped portion inclined surface. The outlet opening of the mixing section channel formed in a step structure and communicating with the inclined surface on the downstream side of the spray medium channel is a wide-angle jet hole, and the stepped portion inclined surface of the spray medium channel Formed in communication with Is characterized in that the outlet opening of the case section passage with a narrow angle injection holes.

  According to such a burner tip structure, the spray medium main channel formed on the upstream side of the axial center position of the burner tip main body, and a plurality of mixed section flows formed by branching radially outward from the spray medium main channel. And a plurality of fuel oil passages formed on the outer periphery of the spray medium main flow passage and joined to the side surface in the vicinity of the inlet of the mixing section flow passage, and the inlet openings are arranged at equal pitches in the circumferential direction. The inside of the main flow path has a two-stage structure in which a downstream end inclined surface and a stepped portion inclined surface are formed, and the mixing section flow path formed in communication with the downstream end inclined surface of the spray medium flow path Since the outlet opening is a wide-angle ejection hole and the outlet opening of the mixing section channel formed in communication with the inclined surface of the stepped portion of the spray medium channel is a narrow-angle ejection hole, the size and shape of the burner tip body Enough mixing distance without increasing the size It can be.

  According to the above-described burner tip structure of the present invention, in particular, in the burner tip structure that improves the combustibility by unbalance the jet direction of the atomized fuel, the spray medium is allowed to flow without increasing the size of the burner tip body. A sufficient mixing distance can be secured in the mixing section flow path, and the consumption of the spray medium such as steam can be increased. When such steam consumption can be increased, even in oil-fired boilers that use heavy oil or the like containing poor fuel such as asphalt or VR as fuel oil, the atomization of fuel oil is promoted and dust or NOx is promoted. Can be reduced.

Hereinafter, an embodiment of a burner chip structure according to the present invention will be described with reference to the drawings.
<First Embodiment>
The burner tip structure of the embodiment shown in FIG. 1 is applied to an oil-fired boiler that burns fuel oil. After atomizing fuel oil using steam or air as a spray medium, the atomized fuel is fed into the furnace. It is a two-fluid type to be charged. The fuel oil in this case includes not only general oil types such as heavy oil, but also low-combustibility and high-viscosity heavy crude fuel such as asphalt and VR.

The burner tip structure of FIG. 1 is a two-fluid type in which fuel oil is atomized by the vapor of the spray medium in the burner tip body 10 and is injected into the furnace. In the following description, steam is used as the spray medium.
The illustrated burner tip body 10 includes a steam main channel 11 formed on the upstream side of the axial center position, a plurality of mixing section channels 12A and 12B formed by branching radially outward from the steam main channel 11, steam, A plurality of fuel oil passages 13A and 13B formed on the outer periphery of the main passage 11 and joined to the side surfaces in the vicinity of the inlets of the mixing section passages 12A and 12B and having the inlet openings 13a arranged at equal pitches in the circumferential direction. ing. A steam communication path 14 is provided between each of the steam main flow path 11 and the mixing section flow paths 12A and 12B.

The interior of the steam main channel 11 described above has a two-stage structure in which a downstream end inclined surface 11a and a stepped portion inclined surface 11b are formed. The outlet opening of the mixing section flow path 12A formed so as to communicate with the downstream end inclined surface 11a of the steam main flow path 11 via the steam communication path 14 serves as a narrow-angle jet hole 15A, and the steam main flow path 11 The outlet opening of the mixing section channel 12B formed so as to communicate with the stepped portion inclined surface 11b via the steam channel 14 is defined as a wide-angle jet hole 15B.
In this case, the narrow-angle jet hole 15A and the wide-angle jet hole 15B are arranged so that the wide-angle jet hole 15B is outside the narrow-angle jet hole 15A with respect to the injection angle of the atomized fuel into the furnace with reference to the axial center of the burner tip body 10. It is set to have a large (wide) angle that spreads in the direction.

The steam and fuel oil from the steam main flow path 11 to the narrow-angle jet hole 15A become the atomized fuel through the following path and process.
The steam introduced into the steam main flow path 11 is divided into a plurality of steam communication paths 14, and a part thereof flows into the mixing section flow path 12A. On the other hand, the fuel oil introduced from the fuel oil flow path 13A flows in the vicinity of the inlet side of the mixing section flow path 12A, that is, with respect to the flow of steam immediately after flowing from the steam communication path 14 into the mixing section flow path 12A. It flows from diagonally behind the road side. In this way, when the steam and the fuel oil merge on the upstream side of the mixing section flow path 12A, the fuel oil is atomized by the collision and agitation at the time of merging to become the atomized fuel, and this atomized fuel becomes the atomized fuel in the mixing section flow path 12A. A narrow angle injection hole 15A that opens to the downstream side is introduced into the furnace at a wide angle.

The steam and fuel oil from the steam main flow path 11 to the wide-angle jet hole 15B become the atomized fuel through the following route and process.
The steam introduced into the steam main flow path 11 is divided into a plurality of steam communication paths 14 and a part thereof flows into the mixing section flow path 12B. On the other hand, the fuel oil introduced from the fuel oil flow path 13B flows in the vicinity of the inlet side of the mixing section flow path 12B, that is, with respect to the flow of steam immediately after flowing into the mixing section flow path 12B from the steam communication path 14. It flows in from the side of the road side. In this way, when the steam and the fuel oil merge on the upstream side of the mixing section flow path 12B, the fuel oil is atomized by the collision and agitation at the time of the merge, and becomes the atomized fuel. A narrow angle injection hole 15B that opens to the downstream side is introduced into the furnace at a wide angle.

Here, the stepped portion inclined surface 11 b is obtained by retreating a part of the downstream end inclined surface 11 a toward the inlet side of the steam main channel 11. In other words, the stepped portion inclined surface 11b is formed so that the downstream end portion of the steam main flow passage 11 where the steam communication passage 14 communicating with the mixing section flow passage 12B having the wide-angle ejection hole 15B opens is convexly retreated. Formed. Accordingly, the downstream end portion in the steam main flow path 11 has a two-stage structure in which the concave portion in which the downstream end inclined surface 11a is formed and the convex portion in which the step inclined surface 11b is formed form irregularities. ing.
In addition, regarding the inclination angles of the downstream end inclined surface 11a and the stepped portion inclined surface 11b, it is desirable that each inclined surface is orthogonal to the axis of the steam communication passage 14 or as close to orthogonal as possible. By setting such an inclination angle, the amount of steam flowing from the steam main flow path 11 to the plurality of steam communication paths 14 can be made substantially uniform.

  And since the wide-angle jet hole 15B was formed in the step part inclined surface 11b side of a convex part, the flow path length of the mixing area flow path 12B is extended by the retreating part of an inclined surface. As a result, by connecting the fuel oil flow path 13B in the vicinity of the inlet side of the mixing section flow path 12B, the problem that it is difficult to secure the mixing distance L2 on the wide-angle injection hole side in the conventional structure is solved, and a sufficient length is achieved. The mixing distance L2 can be ensured. In this case, since the improvement of the burner tip body 10 is in the space of the steam main flow path 11, it is not necessary to increase the size and shape of the outer diameter of the burner tip body 10.

<Second Embodiment>
Next, a second embodiment of the burner chip structure according to the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the part similar to embodiment mentioned above, and the detailed description is abbreviate | omitted.
The burner tip structure of FIG. 2 is a two-fluid type in which fuel oil is atomized by the vapor of the spray medium in the burner chip main body 10A and introduced into the furnace, and steam is used as the spray medium.

  The illustrated burner tip body 10A includes a steam main channel 11 formed on the upstream side of the axial center position, a plurality of mixing section channels 12C and 12D formed by branching radially outward from the steam main channel 11, steam, A plurality of fuel oil passages 13A and 13B formed on the outer periphery of the main passage 11 and joined to the side surfaces in the vicinity of the inlets of the mixing section passages 12C and 12D and having the inlet openings 13a arranged at equal pitches in the circumferential direction. ing. A steam communication path 14 is provided between the steam main flow path 11 and the mixing section flow paths 12A and 12B.

The inside of the steam main flow path 11 described above has a two-stage structure in which a downstream end inclined surface 11a and a stepped portion inclined surface 11c are formed. The outlet opening of the mixing section channel 12D formed so as to communicate with the downstream end inclined surface 11a of the steam main channel 11 via the steam communication passage 14 is a wide-angle jet hole 15B, and the steam main channel 11 The exit opening of the mixing section flow path 12C formed so as to communicate with the stepped portion inclined surface 11c via the vapor flow path 14 is defined as a wide-angle jet hole 15A.
In this case, the stepped portion inclined surface 11c is formed so as to partially widen the inlet opening of the steam main flow channel 11, that is, by partially removing the side wall surface of the steam main flow channel 11. A narrow-angle jet hole 15A communicates with the inclined surface 11c.

Since the steam main flow path 11 having such a two-stage structure having the stepped portion inclined surface 11c and the narrow-angle injection hole 15A having a small inclination angle with respect to the burner tip body 10A are formed, the stepped portion inclined surface 11c is retracted. The channel length of the mixing section channel 12C can be extended by the same amount. Furthermore, since the mixing section flow path 12C formed on the side of the stepped portion inclined surface 11c is a narrow-angle ejection hole 15A, the flow path length of the mixing section flow path 12C can be extended by a small inclination angle. Therefore, a sufficient mixing distance L1 can be secured on the narrow-angle jet hole 15A side.
On the other hand, on the wide-angle jet hole side where it is difficult to secure the mixing distance in the conventional structure, the arrangement is formed on the downstream end inclined surface 11a side where the mixing distance is easy to secure originally, so a sufficiently long mixing distance L2 is secured. can do.

  As a result, the problem that the conventional structure cannot secure a sufficient mixing distance on the wide-angle side can be solved, and a sufficiently long mixing distance L2 can be ensured on both the narrow-angle side and the wide-angle side. In this case, since the improvement of the burner tip body 10 is in the space of the steam main flow path 11, it is not necessary to increase the size and shape of the outer diameter of the burner tip body 10.

As described above, according to the burner tip structure of the present invention described above, the diameter of the burner tip body, in particular, the diameter of the flow path for flowing the spray medium such as steam without increasing the outer diameter is increased, and the mixing section flow path is formed. A sufficient mixing distance is ensured, and the fuel oil can be finely atomized. That is, the mixing distances L1 and L2 that are two to three times as large as the flow path diameters D1 and D2 can be secured. Therefore, even when the injection direction of the atomized fuel is unbalanced to improve the combustibility, the steam consumption can be increased. And if such an increase in steam consumption becomes possible, even in oil-fired boilers that use heavy oil or the like containing poor fuel such as asphalt or VR as fuel oil, the atomization of the fuel oil will be promoted and dust will be promoted. And NOx emissions can be reduced.
In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary, it can change suitably.

It is sectional drawing (AA sectional drawing of FIG. 3) of the example of an internal structure which shows 1st Embodiment about the burner chip | tip structure which concerns on this invention. It is sectional drawing (AA sectional drawing of FIG. 3) of the example of an internal structure which shows 2nd Embodiment about the burner chip | tip structure which concerns on this invention. It is the external view which looked at the conventional burner tip structure which unbalanced the injection injection direction of atomization fuel from the front-end | tip part side. It is sectional drawing which shows the example of an internal structure about the conventional burner chip | tip structure shown in FIG.

Explanation of symbols

10, 10A Burner tip body 11 Steam main flow path 11a Downstream end inclined surface 11b, 11c Stepped portion inclined surface 12A, 12B, 12C, 12D Mixed section flow path 13A, 13B Fuel oil flow path 15A Narrow angle injection hole 15B Wide angle injection Hole

Claims (2)

In the two-fluid burner tip structure in which fuel oil is atomized by a spray medium in the burner tip body and is injected into the furnace.
A spray medium main channel formed upstream of the axial center position of the burner tip body, a plurality of mixing section channels formed by branching radially outward from the spray medium main channel, and the spray medium main channel A plurality of fuel oil passages formed on the outer periphery, joined to the side surface near the inlet of the mixing section flow passage, and the inlet openings are arranged at an equal pitch in the circumferential direction,
The mixing section in which the inside of the spray medium main flow path has a two-stage structure in which a downstream end inclined surface and a stepped portion inclined surface are formed and communicated with the downstream end inclined surface of the spray medium flow path. The outlet opening of the mixing section channel formed in communication with the inclined surface of the stepped portion of the spray medium channel is a wide-angle ejection hole. Burner tip structure. In the two-fluid burner tip structure in which fuel oil is atomized by a spray medium in the burner tip body and is injected into the furnace.
A spray medium main channel formed upstream of the axial center position of the burner tip body, a plurality of mixing section channels formed by branching radially outward from the spray medium main channel, and the spray medium main channel A plurality of fuel oil passages formed on the outer periphery, joined to the side surface near the inlet of the mixing section flow passage, and the inlet openings are arranged at an equal pitch in the circumferential direction,
The mixing section in which the inside of the spray medium main flow path has a two-stage structure in which a downstream end inclined surface and a stepped portion inclined surface are formed and communicated with the downstream end inclined surface of the spray medium flow path. The outlet opening of the flow path is a wide-angle jet hole, and the outlet opening of the mixing section flow path formed in communication with the stepped portion inclined surface of the spray medium flow path is a narrow-angle jet hole Burner tip structure.

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