JPH05187601A - In-bed heat transfer tube for fluidized bed boiler - Google Patents

Abstract

PURPOSE:To obtain an in-layer heat transfer tube for a fluidized bed boiler capable of reducing the cost of work, absorbing thermal expansion and providing a large heat surface. CONSTITUTION:Sleeve-like protectors 1, 3 and 6 are mounted to the outer peripheral parts of bends of heat transfer tubes 2, 4 and 6, thereby forming a double tube. The double tubes are bent in one piece so as to form the bending portions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-layer heat transfer tube for a fluidized bed boiler having a protector at a bend portion applied to commercial and industrial thermal power generation facilities.

[0002]

2. Description of the Related Art In a conventional fluidized bed boiler, a fluidized bed 11
An example of the heat transfer tube 20 arranged inside is shown in FIG. In the fluidized bed boiler, the behavior of coal, fluid material (usually limestone) and ash in the fluidized bed 11 is severe and the heat transfer tube 20 is in a high wear atmosphere, and a protector is attached to the heat transfer tube 20 for protection thereof. .. In the same heat transfer tube 20,
In particular, in the bend pipe portion near the furnace wall 10 shown by B in FIG. 7, coal, fluid and ash easily pass through the gap 12 between the furnace wall 10 and the heat transfer pipe 20, and other straight pipe portions It is in a state where it is more easily worn compared to. Therefore, a box protector as shown in FIGS. 5 and 6 is attached to protect the heat transfer tube 20.

That is, a short tube sleeve 14 is attached to and welded to the heat transfer tube 20, and then a box-shaped protector including the sleeve 14, a shield plate 15, a side plate 16, an upper plate 17, a lower plate 18 and a front plate 19 is attached. ing. The box protector is
Normally, two panels are used as one set, and the bend portion A of the heat transfer tube 20 is used.
Covers.

[0004]

The problems of the heat transfer tube provided in the fluidized bed of the conventional fluidized bed boiler will be described below.

1. As shown in FIG. 6, after the short tube sleeve 14 is attached and welded to the heat transfer tube 20, it is necessary to attach the shield plate 15, the side plate 16, the upper plate 17, the lower plate 18 and the front plate 19, so that the number of parts is reduced. However, it requires a lot of time for processing, welding and mounting. In addition, each plate forming the box is large and has a structure in which thermal deformation easily occurs in the fluidized bed 11 at high temperature (about 850 ° C.).

2. The portion covered with the box-shaped protector does not function as a heat transfer surface because it is shielded despite the presence of the heat transfer tube 20, and it is a wasteful base for that portion. It is necessary to add more heat area to the straight pipe section, which increases the material cost.
There are many factors that increase the layout space and increase the cost.

The present invention is intended to solve the above problems and provide an in-layer heat transfer tube of a fluidized bed boiler which has a simple structure and can be effectively utilized as a bend portion and a heat transfer surface. is there.

[0008]

DISCLOSURE OF THE INVENTION According to the present invention, in an in-layer heat transfer tube of a fluidized bed boiler in which an evaporator tube, a superheater tube, a reheater tube and the like are arranged in a fluidized bed, the outer circumference of a bend part of the heat transfer tube is provided. A sleeve-shaped protector was attached to the portion to form a double pipe, and this was bent integrally to form a bend portion.

[0009]

According to the present invention, the sleeve protector is attached to the outer periphery of the bend portion of the heat transfer tube to form a double tube, and the bend portion is formed by integrally bending the double tube, so that the number of components can be greatly reduced. To be done. In addition, welding is not required, the number of parts is reduced, the number of steps is greatly reduced, and the protector itself is cooled by contacting the heat transfer tube, so that the problem of thermal deformation does not occur.

Further, since the heat transfer tube is not fixed by welding or the like in its longitudinal direction, it is possible to absorb heat expansion.

Further, unlike the box protector, the fluidized bed and the heat transfer tube are not shielded, and the double tube in which the heat transfer tube and the protector are integrated is arranged in the fluidized bed, so that It can also be used effectively as a heat surface, eliminating space.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS.

In this embodiment, first, as shown in FIG.
The sleeve-shaped protector 5 is attached to the outer peripheral portion of the portion corresponding to the bend portion of the heat transfer tube 6 in the straight pipe state. Next, as shown in FIG. 3, the high-frequency induction coil 7 is put on the inner surface of the heat transfer tube 6, the heat transfer tube 6 and the protector 5 are integrally heated from the inner surface, and then bent by a bender, as shown in FIG. Set the shape required for the section.

More specifically, the shape of the bend of the heat transfer tube is as shown in FIG.
There are a large-diameter curved heat transfer tube 4 and a small-diameter curved heat transfer tube 6 (in FIGS. 2 to 4, the small-diameter curved heat transfer tube 6 is shown as a representative of these). Further, since the sleeve-shaped protector is also integrated with the heat transfer tube, the double-curve protector 1, the large-diameter bend protector 3, and the small-diameter bend protector 5 are provided (FIGS. 2 to 4).
Then, the small-diameter bend protector 5 is shown as a representative of these). Since the lengths of the protectors 1, 3 and 5 are configured so as to be installed so as to keep a constant distance from the furnace wall surface of the fluidized bed boiler, the lengths are set and set in advance according to the bend portion of the heat transfer tube. To do.

The heat transfer tubes 2, 4, 6 are, for example, chrome steel tubes, and the protectors 1, 3, 5 are, for example, wear resistant stainless steel tubes.
The protectors 1, 3, 5 having an inner diameter larger than the outer diameters of the heat transfer tubes 2, 4, 6 by 1 to 2 m / m are mounted. The smaller the clearance at the time of mounting, the better. However, in order to ensure the ease of the mounting work, the clearance having the above size is selected.

After forming bends by bending with the bender, protectors 1, 3, 5 and heat transfer tubes 2, 4, 6 are installed in the fluidized bed of the fluidized bed boiler as shown in FIG. To do.

In the present embodiment, even if thermal expansion occurs between the adjacent bend portions of the heat transfer tubes 2, 4, 6 due to heating in the fluidized bed, the heat transfer tubes 2, 4, 6 are longitudinally elongated. Since it is not fixed by welding or the like, the movement is not restricted and the thermal elongation can be absorbed.

Further, the number of parts can be greatly reduced and the number of manufacturing steps can be reduced, and since the integral heat transfer tube protector is directly arranged in the fluidized bed, the bend portion also serves as a heat transfer surface. Can also be used effectively.

Furthermore, since the protectors 1, 3, 5 are in contact with and integrated with the heat transfer tubes 2, 4, 6, the protectors 1, 3, 5 are cooled by the heat transfer tubes 2, 4, 6 and are heated to a high temperature. Even in the fluidized bed atmosphere (usually about 850 ° C.), the protectors 1, 3, 5 do not undergo thermal deformation.

[0020]

The present invention can exert the following effects.

1. By attaching a protector to the heat transfer tube to form a double tube and bending it integrally to form a bend, the required heat transfer tube protector can be manufactured, which greatly reduces the number of parts and reduces the processing cost. Since it is possible to reduce the amount and the welding work is not necessary, the quality can be improved. Furthermore, since the protector itself is in contact with and integrated with the heat transfer tube, the protector is cooled by the heat transfer tube, and the protector does not undergo thermal deformation even in a high temperature atmosphere.

2. Since the heat transfer tube is not fixed in the longitudinal direction by welding or the like, it is possible to absorb the heat expansion.

3. Unlike conventional box protectors, the fluidized bed and heat transfer tube are not shielded, and the bend part of the double pipe structure in which the heat transfer tube and the protector are integrated is directly arranged in the fluidized bed, so that the bend part is Can be effectively used as a heat transfer surface, and the part of the heat transfer tube in the box-shaped protector which has conventionally been a wasted space can also be used as a heat transfer surface. As a result, the heat transfer surface arrangement space can be made compact, and the boiler can be made compact. In addition, since the heat transfer tube in the above-mentioned part, which has been a wasteful space in the past, also becomes an effective heat transfer surface, the heat transfer surface added to the straight pipe part in the related art is unnecessary, and the material cost can be reduced. it can.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is an explanatory view showing a state in which a protector is inserted in the heat transfer tube in the embodiment.

FIG. 3 is an explanatory view of a state in which a high frequency induction coil is put into a heat transfer tube and heated in the embodiment.

FIG. 4 is an explanatory view showing a state in which the heat transfer tube and the protector are bent into a required shape by a bender after heating in the embodiment.

FIG. 5 is a perspective view showing a box-shaped protector for an in-tube heat transfer tube of a conventional fluidized bed boiler.

FIG. 6 is a perspective view of each constituent part in which the part A in FIG. 5 is further developed.

FIG. 7 is an explanatory diagram of an in-pipe heat transfer tube of a conventional fluidized bed boiler.

[Explanation of symbols]

 1,3,5 protector 2,4,6 heat transfer tube 3 high frequency induction coil 10 furnace wall 11 fluidized bed 12 skimmer between furnace wall and heat transfer tube 14 sleeve 15 shield plate 16 side plate 17 upper plate 18 lower plate 19 front plate 20 Heat transfer tube

Claims (1)

[Claims] 1. An in-layer heat transfer tube for a fluidized bed boiler, wherein an evaporator tube, a weekly heater tube, a reheater tube, etc. are provided in a fluidized bed, and a sleeve-shaped protector is provided on an outer peripheral portion of a heat transfer tube bend portion. An in-layer heat transfer tube for a fluidized bed boiler, which is equipped with a double tube and is bent integrally to form a bend.