JPH0949613A - Pulverized fuel combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the work of a furnace wall surface panel or a burner panel and contrive the simplification of a structure as well as the improvement of property of maintenance by a method wherein the shape of a burner nozzle or a burner throat is formed so as to be asymmetrical with respect to a vertical surface and the opening surface of an end part is positioned in the same plane as the side surface of the furnace or in a plane parallel to the same. SOLUTION: The axial line 8 of injecting direction of pulverized fuel and transfer air into a furnace is coaxial with the axial line of injecting direction of auxiliary air for combustion into the furnace while the vertical surface, including these coaxial lines, is not orthogonal to the side surface 7 of the furnace and is slanted. The shape of a burner nozzle is asymmetrical with respect to the vertical surface including the axial line 8 of injecting direction. Such a shape is employed, whereby the opening surface 2 of the burner nozzle can be positioned in the same plane as the side surface 7 of the furnace and combustion can be effected without generating a phenomenon, in which flame is collided against a furnace or is ran along the furnace wall tube 6, even when the furnace wall tube is not arranged so as to be faced toward an air box with an angle between the side surface of the furnace as a traditional manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulverized fuel combustion apparatus applied to a boiler furnace for thermal power generation, a chemical industrial furnace, and the like.

[0002]

2. Description of the Related Art FIG. 7 is a horizontal sectional view showing an example of a conventional pulverized fuel combustion apparatus. In the drawing, (1) is a burner nozzle, (2) is a burner nozzle opening surface, (3) is a fine powder fuel supply pipe, (4) is a combustion auxiliary air supply path, (5) is a wind box, and (6) is a furnace. A wall tube, (7) shows a furnace side surface, and (11) shows an extension surface of the furnace side surface, respectively.

A mixed flow of pulverized fuel and carrier air passes through a pulverized fuel supply pipe (3), is guided to a burner nozzle (1), and is jetted from a burner nozzle opening surface (2) into the furnace. . The combustion auxiliary air passes through the combustion auxiliary air supply path (4) and is guided to the burner nozzle (1), and the burner nozzle opening surface (2) is introduced like the fine powder fuel and the carrier air.
Ejects from inside the furnace. The vertical plane passing through the jetting direction axis (8) is not orthogonal to the furnace side surface (7) and is inclined. The jetted pulverized fuel, carrier air and combustion auxiliary air form a flame while diffusing and mixing in the furnace. At this time, if the flame collides with the furnace wall tube (6) or a phenomenon such as licking the furnace wall surface (6) occurs, the flame is cooled by the furnace wall tube (6), and unburned components in the ash are burned. There is a possibility that the combustibility deteriorates due to an increase or the clinker is attached to the furnace wall tube (6), so-called clinker trouble occurs. Therefore, conventionally, in order to prevent the flame from colliding with the furnace wall tube (6), the furnace wall tube located near the burner nozzle (1) should be placed on the extension surface (11) of the furnace side surface. In consideration of the spread of flame, the wind box (5) is formed at an angle α with the furnace side surface (7) as indicated by reference numeral (26).
They were arranged side by side.

The axis of the jetting direction in which the auxiliary combustion air is jetted into the furnace is coaxial with the axis of the jetting direction (8) in which the fine powder fuel and the carrier air are jetted into the furnace. The cross-sectional shape of the burner nozzle (1) is symmetrical with respect to the left and right with respect to the vertical plane passing through the ejection direction axis (8).

FIG. 8 is a structural conceptual diagram of a furnace wall tube (6) arranged around the conventional pulverized fuel combustion apparatus, a so-called burner panel structural conceptual diagram (plan view). Each line element shown in the figure means one furnace wall tube (6).

[0006]

SUMMARY OF THE INVENTION The above-mentioned conventional fine powdery fuel combustion apparatus has the side surface of the furnace (see the reference numeral (26)) in consideration of prevention of increase of unburned matter in ash and prevention of clinker trouble. 7) and are arranged so as to be lined up toward the wind box (5) side at an angle α, and the structure is such that the ability can be sufficiently exerted. However, by adopting such a structure, the following problems have arisen and improvements have been required. 1) Since part of the furnace wall tube (26) is not located in the same plane as the furnace side surface (7) or the extension surface (11) of the furnace side surface, it is not easy to fabricate the furnace wall tube panel or the burner panel. .

2) The furnace wall support structure has a complicated structure.

3) In the case of a large-capacity burner or large-capacity boiler, the length L of the furnace wall tube row indicated by reference numeral (26) in FIG. 7 becomes long in the furnace width or the furnace depth. It becomes difficult to access the area around the furnace wall, which may cause inconvenience to maintenance.

4) Since the burner nozzle (1) is arranged relatively outside the furnace, the maintainability is easily impaired.

[0010]

In order to solve the above-mentioned conventional problems, the present inventor has proposed a burner nozzle provided on the side surface of a vertical rectangular tube-shaped furnace for ejecting a mixed flow of fine powder fuel and air. Or a burner throat, a pulverized fuel supply pipe connected to the burner nozzle or the burner throat to supply pulverized fuel and air, and a wind box forming a combustion auxiliary air supply passage around the pulverized fuel supply pipe. In a fine powder fuel combustion device in which the vertical plane passing through the ejection direction axis of the mixed flow is not orthogonal to the side surface of the furnace, the shape of the burner nozzle or the burner throat is asymmetric with respect to the vertical plane, and The pulverized fuel combustion device, wherein an opening surface of a tip end portion of the burner nozzle or the burner throat is located in a plane which is the same as or parallel to a side surface of the furnace. It is intended to propose.

The pulverized fuel combustion apparatus of the present invention has the above-mentioned structure, and the shape of the burner nozzle or the burner throat is asymmetric with respect to the vertical plane passing through the jet direction axis of the mixed flow of the pulverized fuel and air, and Since the tip end opening surface of the burner nozzle or burner throat is located in the same plane as or parallel to the side surface of the furnace, the mixture of fine powder fuel, carrier air and combustion auxiliary air ejected from the opening surface of the burner nozzle or burner throat The flow can form a flame inside the furnace rather than on the sides of the furnace and its extensions or in the vicinity of these surfaces. Therefore, it is possible to prevent the phenomenon that the flame collides with the furnace wall tube or licks the furnace wall tube.

[0012]

1 is a horizontal sectional view showing a pulverized fuel combustion apparatus according to a first embodiment of the present invention. In the figure, (1) is a burner nozzle, (2) is a burner nozzle opening surface, (3) is a fine powder fuel supply pipe, (4) is a combustion auxiliary air supply passage, (5) is a wind box, and (6) is Furnace wall tube, (7)
Shows the sides of the furnace.

The jet direction axis (8) from which the pulverized fuel and the carrier air are jetted into the furnace is coaxial with the jet direction axis from which the combustion auxiliary air is jetted into the furnace, and the vertical plane passing through these axes is the furnace. The sides (7) are inclined rather than perpendicular.
The shape of the burner nozzle (1) is asymmetric with respect to the vertical plane passing through the ejection direction axis (8), unlike the conventional one shown in FIG. By adopting such a shape, the burner nozzle opening surface (2) can be located in the same plane as the furnace side surface (7),
The flame collides with the furnace wall tube (6) or licks the furnace wall tube (6) without having to arrange the furnace wall tube at an angle to the side surface of the furnace and arranging it toward the wind box side unlike the conventional case. It can be burned without causing a phenomenon.

FIG. 2 shows a conceptual diagram of the structure of the furnace wall tube (6) arranged around the pulverized fuel combustion apparatus of this embodiment, a so-called burner panel structural conceptual diagram (plan view). As compared with the conventional case shown in FIG. 8, it is understood that the present invention can remarkably simplify the burner panel structure.

FIG. 3 is a diagram schematically illustrating the flow state in the vicinity of the burner portion in this embodiment. In this figure, (15) is a schematic view of a fine powder fuel supply pipe or combustion auxiliary air supply passage, (16) is a schematic view of burner nozzle,
The arrow (17) shows the velocity distribution of the pulverized fuel and the carrier air or combustion auxiliary air in the axial direction of the jet into the furnace, and (18) shows the direction of the side wall of the furnace and the furnace wall tube arranged toward the wind box side at an angle α. A schematic diagram and an arrow (19) show a schematic diagram of the swirling flame in the furnace.

The pulverized fuel combustion apparatus of this embodiment differs from the conventional burner in basic flow characteristics in the vicinity of the burner. First, as shown in FIG. 3 (a), the burner nozzle opening surface (2) has an angle β with respect to the surface perpendicular to the jetting direction axis (8) of the fine powder fuel and the carrier air into the furnace. In the form, in the burner nozzle wall surface (20) where the flow paths of the jets of the pulverized fuel and the carrier air or the combustion auxiliary air become long, the wall surface on the opposite side, that is, the flow passage of the jets of the pulverized fuel and the carrier air or the combustion auxiliary air Since the jet pressure loss becomes larger than that of the burner nozzle wall surface (21) whose length is shortened, the jetting direction of the jet flow is actually deviated from the axis (8) as shown by the arrow (22) on the wall surface (21) side. To deflect. The degree of deflection depends on the angle β and the coefficient of frictional resistance of the inner surfaces of the wall surfaces (20) and (21).

Further, as shown in FIG. 3B, in the conventional pulverized fuel combustion apparatus, the jet flow is caused by the influence of the furnace wall tube (18) arranged toward the wind box side at an angle α with the furnace side surface. Has a tendency to be deflected from the axis line (8) as shown by (23), but in the present embodiment, since the arrangement of the furnace wall tube is different from that of such a furnace wall tube (18), the degree of deflection is Becomes smaller and the jet becomes as shown by (24).

As described above, in addition to the influence of the flow pattern in the vicinity of the burner portion being different from that of the conventional pulverized fuel combustion apparatus, the influence of the swirling flame (19) in the furnace on the jet flow finally leads to the burner in the present embodiment. The jet direction of the jet (22) is actually up to 15 to 20 degrees from the axis (8).
Presumed to be biased.

FIG. 4 is a horizontal sectional view showing a pulverized fuel combustion apparatus according to a second embodiment of the present invention. Instead of the burner nozzle (1) of the first embodiment shown in FIG. 1, This is an example in which a burner throat (9) is adopted. In this figure, (10) is the burner throat opening surface,
(11) indicates an extension surface of the side surface of the furnace. Other symbols (3) to (8) are defined as in FIG.

The burner throat (9) can be formed of a refractory material or the like. The sectional shape of the burner throat (9) is asymmetrical with respect to the vertical plane passing through the axis (8) as a plane of symmetry, as in the case of FIG. In the present embodiment, the burner throat opening surface (10) is not located in the same plane as the furnace side surface (7) and the furnace side surface extension surface (11), but in the parallel planes near these surfaces. As in the case of 1, the combustion can be performed without the flame colliding with the furnace wall tube (6) or the phenomenon of licking the furnace wall tube (6).

FIG. 5 is a horizontal sectional view showing a pulverized fuel combustion apparatus according to the third embodiment of the present invention. In this embodiment, a swirler disperser (13) is provided on the bent portion (12) where the fine powder fuel supply pipe (3) is connected to the burner nozzle (1) or on the burner nozzle (1) side of the bent portion (12). This is an example of a pulverized fuel combustion device which is a pulverized fuel supply pipe (3) in which a core type density converter (14) is installed near the burner nozzle (1).

In this figure, the mixed flow of the pulverized fuel and the carrier air flowing into the bent portion (12) in the direction of the arrow causes a density distribution due to the centrifugal force in the bent portion (12), and the concentration of the pulverized fuel is increased. Becomes thicker on the outer peripheral side of the bent portion (12) and, conversely, becomes thinner on the inner peripheral side. This density distribution is dispersed by the action of the swirler type disperser (13) so that the distribution becomes uniform. Thereafter, the mixed flow having a uniform concentration is subjected to density separation by a core type density separator (14) so as to obtain an optimum combustion state, and is jetted into the furnace through the burner nozzle (1).

FIG. 6 is a front view of the pulverized fuel combustion apparatus according to the fourth embodiment of the present invention as seen from inside the furnace. In the present embodiment, the wind box (5) includes a plurality of unit wind boxes (two in the illustrated example) each including two fine powder fuel supply pipes (3) and five combustion auxiliary air supply passages (4). They are formed separately from each other. In the figure, the burner nozzle opening surface (2) has a plurality of types of shapes such as a triangle, a rectangle, and a shape formed by combining a semicircle and a straight line.

[0024]

According to the present invention, the following effects can be obtained.

1) The work of the furnace wall tube and the burner panel becomes easy.

2) A furnace wall support structure having a low cost and a simple structure can be adopted.

3) Even in the case of a large-capacity burner or large-capacity boiler, access to the periphery of the furnace wall can be facilitated and maintainability can be improved.

4) The positions of the burner nozzle and the burner throat can be arranged on the inner side of the furnace more than ever before, and the maintainability can be improved.

[Brief description of drawings]

FIG. 1 is a horizontal sectional view showing a pulverized fuel combustion apparatus according to a first embodiment of the present invention.

FIG. 2 is a structural conceptual diagram of a furnace wall tube according to the above embodiment.

FIG. 3 is a diagram schematically illustrating a flow state near the burner portion in the above embodiment.

FIG. 4 is a horizontal sectional view showing a pulverized fuel combustion apparatus according to a second embodiment of the present invention.

FIG. 5 is a horizontal sectional view showing a pulverized fuel combustion apparatus according to a third embodiment of the present invention.

FIG. 6 is a front view showing a pulverized fuel combustion apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a horizontal sectional view showing an example of a conventional pulverized fuel combustion apparatus.

FIG. 8 is a structural conceptual diagram of a furnace wall tube related to the conventional pulverized fuel combustion apparatus.

[Explanation of symbols]

(1) Burner nozzle (2) Burner nozzle opening surface (3) Fine fuel supply pipe (4) Combustion auxiliary air supply passage (5) Wind box (6) Furnace wall pipe (7) Furnace side (8) Fine fuel (9) Burner throat (10) Burner throat opening surface (11) Furnace side extension surface (12) Fine powder fuel supply pipe bend (13) Swirler type disperser (14) Core type Density Separator (15) Schematic diagram of supply line for fine powdered fuel or combustion auxiliary air (16) Schematic diagram of burner nozzle (17) Velocity distribution in jet direction (18) Furnace wall tube located on the side of the wind box rather than the side of the furnace (19) Schematic diagram of swirl flame in a furnace (20) Burner nozzle wall surface on the side where the flow path of the jet is long (21) Burner nozzle wall surface on the side where the flow path of the jet is short (22) Jet direction (23) Deflection jet in a conventional burner (24) Deflection jet in a burner according to the present invention (26) Furnace wall tube arranged on the wind box side at an angle α with the side of the furnace

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tomomitsu Yokoyama 2-5-1, Marunouchi, Chiyoda-ku, Tokyo Sanryo Heavy Industries Co., Ltd. (72) Inventor Akiyasu Okamoto 5-717, Fukahori-cho, Nagasaki-shi Nagasaki Research Institute, Mitsubishi Heavy Industries, Ltd.

Claims (1)

[Claims] 1. A burner nozzle or burner throat provided on a side surface of a vertical rectangular tube-shaped furnace for ejecting a mixed flow of fine powder fuel and air, and a fine powder fuel connected to the burner nozzle or burner throat. A fine powder fuel supply pipe for supplying air and a wind box forming a combustion auxiliary air supply passage around the fine powder fuel supply pipe are provided, and a vertical plane passing through the jet direction axis of the mixed flow has a side surface of the furnace. In a fine powder fuel combustion device that is not orthogonal to, the shape of the burner nozzle or burner throat is asymmetric with respect to the vertical plane, and the tip opening surface of the burner nozzle or burner throat is the same as the side surface of the furnace or A pulverized fuel combustion device characterized by being located in parallel planes.