JPH06337101A - Connecting structure for header and steam pipe in pressure fluidized bed boiler - Google Patents

Abstract

PURPOSE:To provide the connecting structure of a header and a steam pipe in a pressure fluidized bed boiler capable of guiding steam to the steam header for reheating steam through a pressure container following the thermal expansion and the expansion and contraction of a main boiler body without causing a large stress. CONSTITUTION:A main boiler body 1 is housed in a pressure container 4. A plurality of steam headers 20 are provided on the bottom of the main boiler body. A steam line 22 passing through the pressure container guides steam to the steam lines 22. The main boiler body is composed of three rhombic posts 1a, 1b and 1c which are adjacent to one another. The steam header is composed of a radial steam pipe 20a and an annular steam pipe 20b which are respectively provided in each of the three rhombic posts. The steam line comprises a horizontal passing part 22a passing through the pressure container, a vertical part 22b extending downward from the horizontal passing part, a horizontal part 22c extending along the inner surface of the pressure container from the vertical part and a horizontal branch part 22d extending from the horizontal part to the radial steam pipe and the annular steam pipe.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for connecting a header and a steam pipe in a pressurized fluidized bed boiler.
The present invention relates to a header and steam pipe connection structure in a hexagonal pressurized fluidized bed boiler.

[0002]

2. Description of the Related Art A pressurized fluidized bed combuster for fluidized combustion of coal under pressure is
The combined cycle combined with a gas turbine has a thermal efficiency of 40% or more, a high in-furnace desulfurization rate, and NO
Since it has features such as a small amount of x generation, it is currently being developed as a new type boiler that replaces the conventional fine powder boiler. Such a pressurized fluidized bed boiler is shown in FIG.
As shown in, the boiler main body 1, the cyclone 2, the bed material storage container 3, etc. are configured to be stored in the pressure container 4, and the coal C supplied from the outside is burned in the boiler main body 1, The exhaust gas is sent to the cyclone 2, and the exhaust gas from which ash has been removed by the cyclone 2 is supplied to an external gas turbine (not shown) for work (for example, driving a generator). Further, in the boiler body 1, a fluidized bed B in which bed material such as coal ash or sand is fluidized by the air A supplied from below is formed. In the fluidized bed B, steam is generated. The evaporator 5, the superheater 6, and the reheater 7 are inserted. Due to the heat generated by the combustion of coal in the fluidized bed B, water is evaporated in the evaporator 5 to become steam, and the steam is further heated in the superheater 6 to become superheated steam, which is provided outside. The steam turbine (not shown) expands and does work. Further, the steam whose temperature has dropped in the steam turbine is reheated in the reheater 7 to become superheated steam, and the work is performed again in the external steam turbine. FIG. 4 is an overall configuration diagram of a hexagonal pressurized fluidized bed boiler (hereinafter referred to as a hexagonal fluidized bed boiler) in which the boiler main body 1 is in the form of a hexagonal column. In this figure,
The hexagonal fluidized bed boiler has a configuration in which the boiler body 1, the cyclone 2, the bed material storage container 3, and the like are housed in the pressure container 4 as in FIG. 9, and coal supplied from the outside is supplied to the boiler body. 1 is burned, the exhaust gas is sent to the cyclone 2 via the exhaust gas manifold, and the exhaust gas from which the ash has been removed by the cyclone 2 is supplied to an external gas turbine (not shown) to do work. . Figure 5
It is a perspective view showing the boiler body circumference of a hexagonal fluidized bed boiler, and consists of a hexagonal-pillar boiler body 1, its bottom 10, and a support beam 9 for suspending the boiler body 1. The boiler body 1 and its bottom 10 are shown separately for clarity. The boiler body 1 has three rhombus columns 1a, 1b, and 1c adjacent to each other, there is no partition inside, each surface of the hexagonal column is a water pipe wall, and each corner of the hexagonal column is a header. Has been done. There are rhomboid openings on the upper surfaces of the three rhomboid columns 1a, 1b, and 1c, and the inner layer tube can be taken out from these openings. The bottom 10 of the boiler body 1 is composed of a steam header 8 composed of a hexagon and a trifurcation, and an ash chute 11, and a bed material containing ash can be taken out from the lower surface of the steam header 8 through the ash chute 11. You can do it. FIG. 6 is a horizontal sectional view taken along the line AA of FIG. In this figure, the boiler body 1 has a hexagonal interior in horizontal section, and has six vertical water pipe walls 12a, 12b.
And a hexagonal closed back stay 14. The inside of the hexagon is 3 degrees apart from the center by 120 °.
It is divided into three spaces by the virtual dashed-dotted line of the book. That is, the inside of the hexagon has two adjacent water tube walls 12a, 1
A horizontal section having 2b as two sides of the parallelogram is composed of three spaces of the parallelogram. In each space, one water pipe wall 1
2a, a first layer inner tube group 16a having one end adjacent to the other water tube wall 12b and having vertical planes parallel to each other, and one water tube wall 12a and the first layer Inner tube group 1
The second end of which one end is adjacent to the other end of 6a and whose vertical planes are parallel to each other
And the inner layer tube group 16b. FIG. 7 is another horizontal sectional view having a height different from that of FIG. In this figure,
The steam header 18 is provided outside the water pipe wall 12b in parallel with the water pipe wall.
Is provided to collect the steam generated on the water tube wall 12b. The inside of the boiler body is the same as in FIG.

[0003]

In such a hexagonal fluidized bed boiler, as shown in FIG. 5, the bottom portion 1 of the boiler body 1 is used.
In No. 0, two steam headers 20 for low-temperature reheat steam are arranged facing each other corresponding to each of the three rhombus columns 1a, 1b, and 1c (only the rhombus column 1a is shown in the drawing. ). The steam header 20 needs to be provided with a steam line for guiding steam from the outside, and the steam for reheating needs to be guided from an external steam turbine through the pressure vessel. However, this steam line is relatively thick (for example, an outside diameter of 40
6 mm), so the steam line cannot follow the vertical movement of the boiler body 1 due to thermal expansion and the expansion / contraction of the boiler body 1 due to the pressure difference between the inside and outside, causing large stress in the steam line and reducing the outer diameter. However, there is a problem in that the passage space cannot be secured due to the arrangement when the number is increased. First of the present invention
The invention of is created to solve such problems. That is, an object of the first invention of the present invention is to follow the thermal expansion and expansion / contraction of the boiler main body without causing a large stress to penetrate the pressure vessel into the steam header for reheat steam to supply the steam for reheat. It is to provide a connection structure of a header and a steam pipe in a pressurized fluidized bed boiler that can be guided.

In the above-mentioned hexagonal fluidized bed boiler, as shown in FIG. 7, in the conventional steam header 18, all the water pipes of the water pipe wall 12b are connected to the cylindrical surface of the steam header 18, so that the steam header 18 The length is almost the same as that of the water pipe wall 12b, so that the end portion (shown by B in the figure) of the steam header 18 projects largely outward from the outer surface of the boiler body 1, and the distance to the maintenance passage 21 becomes large. There were problems such as narrowing and necessity of enlarging the pressure vessel. The second invention of the present invention was devised to solve such a problem. That is, the second object of the present invention is to provide a pressurized fluidized bed boiler capable of smoothly guiding the water pipe of the water pipe wall to the steam header without the end portion of the steam header projecting outward from the boiler body. The purpose is to provide a connection structure between the header and the steam pipe.

[0005]

According to the present invention, there is provided a boiler body which is housed in a pressure vessel and forms a fluidized bed therein,
It is composed of a plurality of steam headers for low temperature reheat steam provided at the bottom of the boiler main body, and a steam line that guides steam through the pressure vessel to the steam header. The steam header comprises a pair of radial steam pipes and a pair of radial steam pipes that are respectively provided on the three rhombus pillars and are substantially parallel to two parallel sides of the rhombus of the rhombus pillars. The line is a horizontal penetrating portion that penetrates the pressure vessel in the radial direction, a vertical portion that extends downward from the horizontal penetrating portion, a horizontal portion that extends from the vertical portion along one side of a rhombus, and a branch from the horizontal portion. And a horizontal branch that extends to the radial steam pipe and the annular steam pipe.
A connection structure of a header and a steam pipe in a pressurized fluidized bed boiler is provided. According to a preferred embodiment of the present invention, the horizontal branch portion of the steam line comprises a first branch portion extending in a radial direction and a second branch portion extending in a direction parallel to one side of a rhomboidal pillar, and the first branch portion. Is one of three
The radial steam pipe of one rhomboid column communicates with the horizontal portion, and the second branch portion communicates the annular steam pipe of another adjacent rhomboid column with the horizontal portion.

Further, according to the present invention, the boiler main body is housed in the pressure vessel and forms a fluidized bed therein, and the steam header is provided in parallel with the water pipe wall forming the outer surface of the boiler main body. In the pressurized fluidized bed boiler, the steam header has a total length shorter than a water pipe wall, and a part of a water pipe forming the water pipe wall is connected to an end face of the steam header. A header and steam pipe connection structure is provided.

[0007]

According to the first aspect of the present invention described above, the steam header consisting of the pair of radial steam pipes and the annular steam pipe is provided on each of the three rhombus columns, and the steam header is passed through the pressure vessel to pass the steam. A leading steam line has a horizontal penetrating portion that radially penetrates the pressure vessel, a vertical portion that extends downward from the horizontal penetrating portion, a horizontal portion that extends from the vertical portion along one side of a rhomboid column, and from the horizontal portion. As it consists of a horizontal branch part that branches and extends to the radial steam pipe and the annular steam pipe, even if the boiler main body moves up and down due to thermal expansion, the horizontal part slightly tilts in the vertical direction to follow this vertical movement. You can Further, even if the boiler main body expands / contracts due to the pressure difference between the inside and the outside of the boiler main body, it is possible to follow the expansion / contraction by tilting the horizontal portion slightly in the horizontal direction. Therefore, by making the horizontal portion sufficiently long, it is possible to follow the thermal expansion and expansion / contraction of the boiler body without causing a large stress in the steam line.

Further, according to the second aspect of the present invention, the steam header is provided in parallel with the water pipe wall forming the outer surface of the boiler body, and the total length of the steam header is shorter than that of the water pipe wall. Since part of the water pipes that make up the wall is connected to the end surface of the steam header, the end of the steam header does not project outward from the boiler body, which allows the diameter of the pressure vessel to be reduced and for maintenance purposes. A sufficient distance from the passage can be secured.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. In addition, in each figure, the same parts are denoted by the same reference numerals. 4 to 6 described above,
The same applies to the connection structure of the header and the steam pipe in the pressurized fluidized bed boiler according to the present invention, and the description thereof will be omitted here to avoid duplication. 1 is a first embodiment showing a connection structure between a header and a steam pipe according to the present invention.
(A) is a plan view of the bottom of the boiler body 1 shown in FIG. 5, and FIG. 1 (B) is a side view of FIG. 1 (A). In this figure, a header-steam connection structure according to the present invention is used for a boiler body 1 which is housed in a pressure vessel 4 and forms a fluidized bed therein, and a low-temperature reheat steam provided at the bottom of the boiler body 1. It is composed of a plurality of steam headers 20 and a steam line 22 that penetrates the pressure vessel 4 and guides steam to the steam header 20. The boiler body 1 is composed of three rhombus columns 1a, 1b, and 1c adjacent to each other, as already described in FIG. In addition, in FIG. 1, the boiler main body 1 is shown by a two-dot chain line. The steam header 20 is composed of a radial steam pipe 20a and an annular steam pipe 20b, and the radial steam pipe 20a and the annular steam pipe 20b are three rhombus substantially parallel to two parallel sides of the rhombus of the rhomboid pillars 1a, 1b, 1c. Each pillar is provided. As a result, the low temperature reheated steam extracted from the external turbine can be smoothly supplied to the above-described inner layer tube groups 16a, 16b (FIG. 6) in each of the rhomboid columns 1a, 1b, 1c. The steam line 22 includes a horizontal penetrating portion 22a that penetrates the pressure vessel 4 in the radial direction, a vertical portion 22b that extends downward from the horizontal penetrating portion 22a, and a horizontal portion 22c that extends from the vertical portion 22b along one side of a rhomboid column. And this horizontal part 22
Radial steam pipe 20a and annular steam pipe 20 branched from c
and a horizontal branch portion 22d extending to b. Horizontal part 22
As shown in the figure, it is preferable that c is sufficiently long, and it is preferable that the length is at least about the length of one side of the rhomboidal column unless it overlaps with other steam lines. With such a configuration, even if the boiler main body moves up and down due to thermal expansion, it is possible to follow this vertical movement by tilting the horizontal portion slightly in the vertical direction,
Even if the boiler main body expands / contracts due to the pressure difference between the inside and the outside of the boiler main body, it is possible to follow this expansion / contraction by tilting the horizontal portion slightly in the horizontal direction. Therefore, by making the horizontal portion sufficiently long, it is possible to follow the thermal expansion and expansion / contraction of the boiler body without causing a large stress in the steam line. Further, the horizontal branch portion 22d of the steam line 22 includes a first branch portion 23a extending in the radial direction and a second branch portion 23b extending in the arc direction, and the first branch portion 23a has three rhombus pillars 1a, 1b, 1c. The radial steam pipe 20a of one of the rhombus columns (1a in the figure) communicates with the horizontal portion 22c, and the second branching portion 23b is horizontal with the annular steam pipe 20b of another adjacent rhombus column (1c in the figure). Part 22c
And communicate with. With such a configuration, the radial steam pipe 20a and the annular steam pipe 20b of the same rhomboidal column are connected to the first branch portion 2
The horizontal portion 22c can be made sufficiently long so as not to overlap another steam line, and the stress generated in the steam line can be further reduced, as compared with the case where the 3a and the second branch portion 23b are respectively connected. It is possible to more easily follow the thermal expansion and expansion / contraction of the main body.

FIG. 2 is a second embodiment showing a connecting structure of a header and a steam pipe according to the present invention, and is a view similar to FIG. 7 described above. Further, FIG. 3 is an enlarged perspective view of a C portion of FIG. 2 and 3, a header-steam pipe connection structure according to the present invention includes a boiler main body 1 that is housed in a pressure vessel 4 and forms a fluidized bed therein, and a water pipe wall 12b that forms an outer surface of the boiler main body 1. Steam header 18 provided in parallel with
It consists of and. This structure is similar to the conventional example of FIG. Further, according to the present invention, the entire length of the steam header 18 is shorter than the water pipe wall 12b, and a part of the water pipes forming the water pipe wall 12b (the water pipe near the corner) is the steam header 18b.
Is connected to the end face of. With such a configuration, the end of the steam header does not project outward from the boiler main body, whereby the diameter of the pressure vessel can be reduced, and a sufficient distance from the maintenance passage can be ensured.

[0011]

As described above, according to the first configuration of the present invention, even if the boiler main body moves up and down due to thermal expansion, the horizontal portion slightly tilts in the vertical direction to follow the vertical movement. be able to. Further, even if the boiler main body expands / contracts due to the pressure difference between the inside and the outside of the boiler main body, it is possible to follow the expansion / contraction by tilting the horizontal portion slightly in the horizontal direction. Therefore, according to the present invention, it is possible to increase the total horizontal length even in a narrow space, and it is possible to follow the thermal expansion and expansion / contraction of the boiler body without causing a large stress in the steam line. Furthermore, the second
With this configuration, the end portion of the steam header does not project outward from the boiler main body, so that the diameter of the pressure vessel can be reduced, and a sufficient distance from the maintenance passage can be ensured. Therefore, the connection structure between the header and the steam pipe according to the present invention follows the thermal expansion and expansion / contraction of the boiler body without causing a large stress, and penetrates the pressure vessel through the reheat steam header to reheat steam. , And the water pipe of the water pipe wall can be guided to the steam header without the end of the steam header projecting outward from the boiler body.
And so on.

[Brief description of drawings]

FIG. 1 is a first embodiment showing a connection structure between a header and a steam pipe according to the present invention.

FIG. 2 is a second embodiment showing a connection structure between a header and a steam pipe according to the present invention.

FIG. 3 is an enlarged perspective view of a C portion of FIG.

FIG. 4 is an overall configuration diagram of a hexagonal pressurized fluidized bed boiler.

FIG. 5 is a perspective view showing the vicinity of a boiler body of a hexagonal fluidized bed boiler.

6 is a horizontal sectional view taken along line AA of FIG.

FIG. 7 is another horizontal sectional view having a height different from that of FIG.

FIG. 8 is an overall configuration diagram of a conventional pressurized fluidized bed boiler.

[Explanation of symbols]

 1 Boiler Main Body 2 Cyclone 3 Bed Material Storage Container 4 Pressure Vessel 5 Evaporator 6 Superheater 7 Reheater 8 Steam Header 9 Support Beam 10 Bottom of Boiler Main Body 11 Ash Chute 12a, 12b Water Pipe Wall 16a, 16b Inner Layer Tube Group 18 steam header 20 steam header for low temperature reheat steam 20a radial steam pipe 20b annular steam pipe 22 steam line 22a horizontal penetration part 22b vertical part 22c horizontal part 22d horizontal branch part 23a first branch part 23b second branch part A air B Fluidized bed C coal

Claims (3)

[Claims] 1. A boiler body which is housed in a pressure vessel and forms a fluidized bed therein, a plurality of steam headers for low temperature reheat steam provided at the bottom of the boiler body, and a pressure vessel for the steam header. And a steam line that guides steam through the boiler body, the boiler body is composed of three rhombus columns that are adjacent to each other, and the steam header is provided on each of the three rhombus columns and is parallel to the rhombus of the rhombus columns. Consisting of a pair of radial steam pipes and annular steam pipes substantially parallel to the two sides, the steam line includes a horizontal penetrating portion that radially penetrates the pressure vessel, and a vertical portion that extends downward from the horizontal penetrating portion. In a pressurized fluidized bed boiler, comprising a horizontal portion extending from the vertical portion along the inner surface of the pressure vessel, and a horizontal branch portion branched from the horizontal portion and extending to the radial steam pipe and the annular steam pipe. header And steam pipe connection structure. 2. The horizontal branch portion of the steam line comprises a first branch portion extending in a radial direction and a second branch portion extending in a circular arc direction, and the first branch portion is one of three rhombus pillars. 2. The pressurization according to claim 1, wherein a radial steam pipe communicates with the horizontal portion, and the second branching portion communicates another adjacent rhomboidal circular steam pipe with the horizontal portion. Connection structure of header and steam pipe in fluidized bed boiler. 3. A boiler main body that is housed in a pressure vessel and forms a fluidized bed inside, and a steam header that is provided in parallel with a water pipe wall that forms the outer surface of the boiler main body. Is shorter than the water pipe wall, and a part of the water pipe that constitutes the water pipe wall is connected to the end face of the steam header, and the header and the steam pipe in the pressurized fluidized bed boiler are characterized in that Connection structure.