JPH09112804A - Furnace wall structure of coal fired boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of clinker by reducing triangular cavities inevitably formed above and below a burner throat to reduce an area to be lined with fire-proofing materials without a remarkable increase in the pressure loss in specific heat transfer pipes. SOLUTION: A furnace wall structure is provided which comprises heat transfer pipes 1a to 1i, among which the heat transfer pipes 1a to 1f are bent so as to go around a burner throat 3 symmetrically with respect to a center line 4 which divides the throat 3 into two parts along the arrangement of the pipes 1a to 1i, and the heat transfer pipes 1a and 1b, or 1c and 1d disposed adjacent the center line 4 on one side of the throat 3, either thereabove or therebelow, are rearranged such that these pipes are apart from the center line 4 on the other side of the throat 3 and bent with a small bend radius to bring them as close to the throat 3 as possible. This arrangement reduces triangular cavities inevitably formed above and below the throat 3 to reduce the area to be lined with fire-proof materials.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a furnace wall structure of a coal-fired boiler.

[0002]

2. Description of the Related Art A furnace wall of a coal-fired boiler is constructed by connecting a plurality of heat transfer tubes extending in the vertical direction via fins. A burner opened at a position where a burner is to be arranged. In the throat portion, each heat transfer tube is bent so as to bypass the burner throat portion to form a furnace wall.

3 and 4 show an example of a conventional furnace wall structure in a burner throat section. In the drawings, 1a to 1i are heat transfer tubes extending in the vertical direction, and 2 is a space between the heat transfer tubes 1a to 1i. The connecting fins 3, reference numeral 3 denotes a burner throat portion, and reference numeral 4 denotes a center line that divides the burner throat portion 3 into two in the direction in which the heat transfer tubes 1a to 1i are arranged. The burner throat portion 3 is symmetrical about the center line 4 as an axis. Some heat transfer tubes 1a to 1 so as to bypass
f is bent, and the bent heat transfer tubes 1a to 1f are arranged with their phases shifted inward and outward of the furnace wall so as not to interfere with each other.

In such a conventional structure, each heat transfer tube 1a
The heat transfer tubes 1a, 1b that are close to the center line 4 on the upper side and the lower side of the burner throat portion 3 are arranged because the burner throat portion 3 is circumvented by bending deformation of 1f itself.
Can be bent only with a relatively large bending radius, and a cavity as indicated by X in FIG. 3 is formed in a triangular shape on the upper side and the lower side of the burner throat portion 3, and this cavity is formed. The burner throat portion 3 was filled with the refractory material 5 to form a circular shape.

Since it is difficult to connect the curved portions of the heat transfer tubes 1a to 1f with the fins 2 like other straight portions, it is difficult to connect the curved portions of the heat transfer tubes 1a to 1f. Also, the refractory material 5 is embedded so that no gap is formed.

However, the refractory material 5 embedded in the upper and lower cavities of the burner throat portion 3 is the heat transfer tube 1.
Since the work is performed in a state where it is exposed to the inside of the furnace at a position where the cooling effect of a and 1b cannot be expected, the surface temperature rises remarkably as the temperature inside the furnace rises, and the molten ash generated by burner combustion becomes There is a problem that it becomes easy to adhere to the surface and clinker is generated by the adhered molten ash and grows large.

On the other hand, the surface of each of the heat transfer tubes 1a to 1f and the refractory material 5 embedded between them are the heat transfer tubes 1a to 1f.
Since the temperature rise was suppressed by the cooling effect of the flowing water of 1f, the molten ash was rarely attached to these surfaces.

Therefore, the inventor of the present invention has proposed the burner throat section 3
An appropriate number of heat transfer tubes 1a, 1b close to the center line 4 on the upper and lower sides of the elbow are brought as close as possible to the burner throat portion 3, and then an elbow (fixed pipe joint for changing the pipe direction to a required angle), etc. Bending with a small bending radius by using, thereby reducing the triangular cavities formed on the upper side and the lower side of the burner throat portion 3 to reduce the construction range of the refractory material 5 and suppress the generation of clinker. I came up with the idea.

[0009]

However, since the arrangement of the heat transfer tubes 1a to 1f is the same on the upper side and the lower side of the burner throat portion 3, a specific heat transfer tube close to the center line 4 is provided. Only 1a and 1b have elbows and other bent portions with a small bending radius, which causes a significant increase in pressure loss. As a result, the flow rate in the specific heat transfer tubes 1a and 1b decreases and the water temperature increases. There is a possibility that problems such as excessive rise may occur.

The present invention has been made in view of the above-mentioned circumstances, and triangular cavities formed on the upper side and the lower side of the burner throat are formed without significantly increasing the pressure loss of a specific heat transfer tube. The purpose is to reduce the construction range of refractory materials and suppress the formation of clinker.

[0011]

SUMMARY OF THE INVENTION According to the present invention, a plurality of heat transfer tubes are bent so that the burner throat section is symmetrically bypassed around a center line that divides the burner throat section into two in the direction of arrangement of the heat transfer tubes. In the furnace wall structure of the coal-fired boiler configured as described above, the heat transfer tubes that are close to the center line on one side of the burner throat on one side and the other side of the burner throat are arranged on the other side so that the heat transfer tubes are spaced from the center line. In addition to rearranging, an appropriate number of heat transfer tubes close to the center line on the upper side and the lower side of the burner throat section are bent as close as possible to the burner throat section with a small bending radius.

Further, it is preferable that an appropriate number of heat transfer tubes adjacent to the center line on the upper side and the lower side of the burner throat section are bent by using elbows.

With this configuration, an appropriate number of heat transfer tubes on the upper side and the lower side of the burner throat, which are close to the center line, are bent as close as possible to the burner throat and bent with a small bending radius by an elbow or the like. Also, since these heat transfer tubes can be rearranged so as to be separated from the center line on the other side of the upper side and the lower side of the burner throat, the heat transfer tubes can be again bent with a small bending radius on the other side of the upper side and the lower side of the burner throat. It is possible to avoid bending, and it is possible to bypass the burner throat section by simply bending it with a relatively large bending radius, which creates a triangular cavity above and below the burner throat section. It becomes possible to reduce the construction range of the refractory material by reducing the size.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an example of an embodiment for carrying out the present invention, and the parts denoted by the same reference numerals as those in FIGS. 3 and 4 represent the same parts.

As shown in FIG. 1, a part of the heat transfer tube 1a is arranged so as to symmetrically bypass the burner throat section 3 about a center line 4 that divides the burner throat section 3 into two in the direction in which the heat transfer tubes 1a to 1i are arranged. 1f is bent to form the furnace wall structure 6 of the coal-fired boiler.

The bent heat transfer tubes 1a to 1f
Are rearranged in such a manner that one that is close to the center line 4 on one of the upper side and the lower side of the burner throat section 3 is separated from the center line 4 on the other side of the upper side and the lower side of the burner throat section 3. In addition, what is close to the center line 4 above and below the burner throat portion 3,
It is bent with a small bending radius via an elbow 7 (a fixed pipe joint that changes the pipe line direction to a required angle) at a position as close as possible to the burner throat portion 3.

That is, the center line 4 is located above the burner throat section 3.
First and second heat transfer tubes 1a, 1 counted from
b is bent with a small bending radius via the elbow 7 at a position as close as possible to the upper end of the burner throat section 3, and the heat transfer tube 1 constituting the furnace wall on the side of the burner throat section 3 is formed.
While passing through the rear side of c, 1d, 1g, 1h, 1i, bypass the burner throat part 3 with a relatively large bending radius, and the fifth and sixth positions are counted from the center line 4 below the burner throat part 3. It is arranged to form the furnace wall.

On the upper side of the burner throat portion 3, the heat transfer tubes 1c and 1d arranged in the third and fourth positions from the center line 4 are bent to have a relatively large bend along the arc shape of the burner throat portion 3. Burner throat part 3 by radius
To form a furnace wall on the side of the burner throat section 3,
The elbow 7 is arranged below the burner throat section 3 and is rearranged first and second from the center line 4 and is as close as possible to the lower end of the burner throat section 3.
Is bent with a small bending radius to form a furnace wall.

Further, on the upper side of the burner throat section 3, the fifth and sixth heat transfer tubes 1e and 1f arranged from the center line 4 constitute the furnace wall on the side of the burner throat section 3. While passing through the back side of the heat tubes 1c, 1d, 1g, 1h, 1i, the burner throat section 3 is bypassed with a relatively large bending radius, and the third and fourth counting from the center line 4 under the burner throat section 3 It is rearranged to form the furnace wall.

In the illustrated example, the heat transfer tubes 1g, 1h, 1i which are separated from the center line 4 by at least the seventh position are not particularly bent, and extend straight in the vertical direction to form a furnace wall. Are configured.

Thus, with this structure, an appropriate number of heat transfer tubes 1a, 1b and 1c, 1d that are close to the center line 4 on the upper side and the lower side of the burner throat portion 3 are connected to the burner throat. Even if it is bent as close as possible to the portion 3 by the elbow 7 with a small bending radius, these heat transfer tubes 1a, 1b
Since the arrangements of 1c and 1c are rearranged so as to be separated from the center line 4 on the other of the upper side and the lower side of the burner throat portion 3, the bending radius is again small on the other side of the upper side and the lower side of the burner throat portion 3. The burner is prevented from being bent, and the burner throat portion 3 can be bypassed only by performing a bending work with a relatively large bending radius, whereby a triangular shape formed on the upper side and the lower side of the burner throat portion 3 is formed. It is possible to reduce the size of the cavity and reduce the construction range of the refractory material 5.

Therefore, according to the above embodiment, the triangular cavities formed on the upper side and the lower side of the burner throat portion 3 are reduced without significantly increasing the pressure loss of only a specific heat transfer tube, and the refractory material is reduced. Since the construction range of 5 can be reduced, it is possible to suppress the generation of clinker due to the molten ash generated by the burner combustion adhering to the surface of the refractory material 5.

Incidentally, the furnace wall structure of the coal-fired boiler of the present invention is
The present invention is not limited to the above-described embodiment, and how to rearrange the arrangement of the heat transfer tubes is not limited to the illustrated example.
In addition, it goes without saying that various changes can be made without departing from the spirit of the present invention.

[0025]

According to the above-mentioned furnace wall structure of the coal-fired boiler of the present invention, the triangles formed on the upper side and the lower side of the burner throat without significantly increasing the pressure loss of only a specific heat transfer tube. Since it is possible to reduce the construction range of the refractory material by reducing the shape of the cavity, it is possible to suppress the formation of clinker due to the molten ash generated by burner combustion adhering to the surface of the refractory material. Can play.

[Brief description of the drawings]

FIG. 1 is a front view illustrating an example of an embodiment of the present invention.

FIG. 2 is a view in the direction of arrows II-II in FIG.

FIG. 3 is a front view showing a conventional example.

FIG. 4 is a view in the direction of arrows IV-IV in FIG. 3;

[Explanation of symbols]

 1a heat transfer tube 1b heat transfer tube 1c heat transfer tube 1d heat transfer tube 1e heat transfer tube 1f heat transfer tube 1g heat transfer tube 1h heat transfer tube 1i heat transfer tube 3 burner throat section 4 centerline 6 furnace wall structure 7 elbow

Claims (2)

[Claims] 1. A furnace for a coal-fired boiler, which is formed by bending a plurality of heat transfer tubes so as to symmetrically detour the burner throat section around a center line that divides the burner throat section into two in the direction in which the heat transfer tubes are arranged. A wall structure, rearranges the arrangement of the heat transfer tubes so that the heat transfer tubes close to the center line on one side above and below the burner throat section are separated from the center line on the other side, and at the same time the burner throat section is arranged. A furnace wall structure for a coal-fired boiler, wherein an appropriate number of heat transfer tubes close to the center line on the upper side and the lower side of the above are bent as close as possible to the burner throat with a small bending radius. 2. The furnace wall of a coal-fired boiler according to claim 1, wherein an appropriate number of heat transfer tubes adjacent to the center line on the upper side and the lower side of the burner throat section are bent by using an elbow. Construction.