JP3346491B2 - Connection structure of header and steam pipe in pressurized fluidized bed boiler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A pressurized fluidized bed boiler (Pressurized Fluidized Bed Combuster) that fluidly burns coal under pressure is
Combined cycle combined with gas turbine has thermal efficiency of 40% or more, high desulfurization rate in furnace, NO
Due to its features such as low x generation, it is currently being developed as a new type of boiler that replaces the conventional fine-powder boiler. Such a pressurized fluidized bed boiler is shown in FIG.
As shown in FIG. 1, the boiler body 1, the cyclone 2, the bed material storage container 3, and the like are configured to be stored in the pressure vessel 4, and the coal C supplied from the outside is burned in the boiler body 1, The exhaust gas is sent to the cyclone 2, 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 perform work (for example, drive a generator). Further, a fluidized bed B in which bed materials such as coal ash and sand are fluidized by air A supplied from below is formed in the boiler main body 1. Evaporator 5, superheater 6, and reheater 7 are inserted. Due to the heat generated by the combustion of the coal in the fluidized bed B, the water evaporates in the evaporator 5 to become steam, and the steam is further heated in the superheater 6 to become superheated steam. This superheated steam is provided outside. The steam turbine (not shown) expands and works. Further, the steam whose temperature has been lowered by the steam turbine is heated again by the reheater 7 to become superheated steam, and works again by 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 body 1 has a hexagonal column shape. In this figure,
The hexagonal fluidized-bed boiler has a configuration in which a boiler main body 1, a cyclone 2, a bed material storage container 3, and the like are stored in a pressure vessel 4, as in FIG. 1, the exhaust gas is sent to a cyclone 2 via an 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) for work. . FIG.
It is a perspective view which shows the boiler main body periphery of a hexagonal fluidized-bed boiler, It consists of the boiler main body 1 of a hexagonal column, its bottom part 10, and the support beam 9 which suspends the boiler main body 1. FIG. The boiler body 1 and its bottom 10 are shown separately for clarity. The boiler body 1 has a configuration in which three rhombic columns 1a, 1b, and 1c are adjacent to each other. There are no partitions inside, each surface of the hexagonal column is formed of a water pipe wall, and each corner of the hexagonal column is formed of a header. Have been. On the upper surfaces of the three rhombic columns 1a, 1b, 1c, there are rhombic openings, through which the inner tube can be taken out. The bottom portion 10 of the boiler main body 1 is composed of a steam header 8 formed of a hexagon and a three-pronged portion, and an ash chute 11, and a bed material containing ash can be taken out from the lower surface of the steam header 8 via the ash chute 11. I can do it. FIG. 6 is a horizontal sectional view taken along line AA of FIG. In this figure, a boiler body 1 has a hexagonal horizontal section and six vertical water pipe walls 12a, 12b.
And a hexagonal closed back stay 14. The inside of the hexagon is 3 ° away from the center by 120 °.
The book is divided into three spaces by a virtual dashed line. That is, the inside of the hexagon is formed by two adjacent water pipe walls 12a, 1a.
A horizontal section having 2b as two sides of a parallelogram is formed of three parallelogram spaces. Each space has one water pipe wall 1
A first inner tube group 16a which is parallel to 2a and one end of which is adjacent to the other water tube wall 12b and whose vertical planes are parallel to each other; and the first layer tube group which is parallel to one water tube wall 12a and Inner tube group 1
6a, one end of which is adjacent to the other end and whose vertical faces are parallel to each other.
And the in-layer tube group 16b. FIG. 7 is another horizontal sectional view having a different height from that of FIG. In this figure,
A 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 pipe wall 12b. The inside of the boiler body is the same as that in FIG.

[0003]

In such a hexagonal fluidized bed boiler, as shown in FIG.
At 0, two steam headers 20 for low-temperature reheat steam are arranged facing each other corresponding to each of the three rhombic columns 1a, 1b, 1c (only the rhombic column 1a is shown in the figure). ). The steam header 20 must be provided with a steam line for guiding steam from the outside, and the steam for reheating must be guided from an external steam turbine through the pressure vessel. However, this steam line is relatively thick (for example, with an outer diameter of 40 mm) due to the limitation of pressure loss.
6 mm), so that the steam line cannot follow the vertical movement of the boiler main body 1 due to thermal expansion or the expansion / contraction of the boiler main body 1 due to a pressure difference between the inside and outside, so that a large stress is generated in the steam line or the outer diameter is reduced. When the number is increased, there is a problem that a passage space cannot be secured due to the arrangement. First of the present invention
The present invention has been made to solve such a problem. 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 generating a large stress, and penetrate the pressure vessel into the steam header for reheat steam to supply the reheat steam. An object of the present invention is to provide a connection structure between 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, since all the water tubes of the water tube wall 12b are connected to the cylindrical surface of the steam header 18, The length of the steam header 18 is substantially the same as the length of the water pipe wall 12b. Therefore, the end of the steam header 18 (indicated by B in the figure) projects greatly outward from the outer surface of the boiler main body 1, and the distance from the maintenance passage 21 is reduced. There have been problems such as narrowing and the necessity of increasing the size of the pressure vessel. The second invention of the present invention has been made to solve such a problem. That is, an object of the second invention of the present invention is to provide a pressurized fluidized bed boiler capable of smoothly guiding a water pipe on a water pipe wall to a steam header without an end of the steam header projecting outward from the boiler body. And a connection structure between the header and the steam pipe.

[0005]

According to the present invention, a boiler body stored in a pressure vessel and forming a fluidized bed therein,
The steam generator includes a plurality of steam headers provided at the bottom of the boiler main body for low-temperature reheat steam, and a steam line that guides steam through the pressure vessel to the steam header. The steam header is provided on each of the three rhombic pillars, and includes a pair of radial steam pipes and an annular steam pipe substantially parallel to two rhombic parallel sides of the rhombic pillar. The line is a horizontal penetration part penetrating the pressure vessel in the radial direction, a vertical part extending downward from the horizontal penetration part, a horizontal part extending along one side of the rhombic column from the vertical part, and branching off from the horizontal part. And a horizontal branch extending to the radial steam pipe and the annular steam pipe.
A connection structure between a header and a steam pipe in a pressurized fluidized-bed boiler, characterized by being provided. According to a preferred embodiment of the present invention, the horizontal branch of the steam line comprises a first branch extending in a radial direction and a second branch extending in a direction parallel to one side of a rhombic column. Is one of three
A radial steam pipe of one rhombic pillar communicates with the horizontal portion, and the second branch portion communicates an annular steam pipe of another adjacent rhombic pillar with the horizontal portion.

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

[0007]

According to the first aspect of the present invention, a steam header comprising a pair of radial steam pipes and an annular steam pipe is provided on each of three rhombic columns, and steam is passed through the pressure header through the steam header. A leading steam line extending radially through the pressure vessel, a vertical portion extending downward from the horizontal penetration portion, a horizontal portion extending from the vertical portion along one side of a rhombic column, and a horizontal portion extending from the vertical portion. Since the boiler body moves up and down due to thermal expansion because it consists of a horizontal branch section that branches and extends to the radial steam pipe and the annular steam pipe, the horizontal section slightly tilts up and down to follow this up and down movement Can be. Further, even if the boiler body expands and contracts due to a pressure difference between the inside and outside of the boiler body, the expansion and contraction can be followed by the horizontal portion being slightly inclined 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 main body without generating a large stress in the steam line.

Further, according to the second configuration of the present invention, a steam header is provided parallel to a water pipe wall forming the outer surface of the boiler main body, and the entire length of the steam header is shorter than the water pipe wall. Since a part of the water pipe constituting the wall is connected to the end face of the steam header, the end of the steam header does not protrude outward from the boiler body, thereby making it possible to reduce the diameter of the pressure vessel and for maintenance. A sufficient distance from the passage can be ensured.

[0009]

Preferred embodiments of the present invention will be described below with reference to the drawings. In the drawings, common parts are denoted by the same reference numerals. 4 to 6 described above,
The same applies to the connection structure between the header and the steam pipe in the pressurized fluidized-bed boiler according to the present invention, and the description is omitted here to avoid duplication. FIG. 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 main body 1 shown in FIG. 5, and FIG. 1 (B) is a side view of FIG. 1 (A). In this figure, a connection structure between a header and a steam pipe according to the present invention is a boiler main body 1 stored in a pressure vessel 4 and forming a fluidized bed therein, and a low-temperature reheat steam provided at the bottom of the boiler main body 1. It comprises a plurality of steam headers 20 and a steam line 22 that guides steam through the pressure vessel 4 to the steam header 20. The boiler body 1 is composed of three rhombic columns 1a, 1b, 1c adjacent to each other, as already described with reference to FIG. In FIG. 1, the boiler main body 1 is indicated by a two-dot chain line. The steam header 20 includes a radial steam pipe 20a and an annular steam pipe 20b. The radial steam pipe 20a and the annular steam pipe 20b have three rhombic shapes substantially parallel to two parallel sides of the rhombic columns 1a, 1b, and 1c. Each pillar is provided. Thus, the low-temperature reheated steam extracted from the external turbine can be smoothly supplied to the above-described in-layer tube groups 16a, 16b (FIG. 6) in each of the rhombic columns 1a, 1b, 1c. The steam line 22 includes a horizontal penetrating part 22a penetrating the pressure vessel 4 in the radial direction, a vertical part 22b extending downward from the horizontal penetrating part 22a, and a horizontal part 22c extending from the vertical part 22b along one side of the rhombic column. And this horizontal part 22
c, the radial steam pipe 20a and the annular steam pipe 20
b. Horizontal part 22
As shown in the figure, it is preferable that c is sufficiently long, and it is particularly preferable that c be about the length of one side of the rhombic column as long as it does not overlap with other steam lines. With this configuration, even if the boiler body moves up and down due to thermal expansion, the horizontal portion can follow this up and down movement by slightly inclining vertically.
Even if the boiler main body expands and contracts due to a pressure difference between the inside and the outside of the boiler main body, the horizontal part is slightly inclined in the horizontal direction, so that the expansion and contraction can be followed. Therefore, by making the horizontal portion sufficiently long, it is possible to follow the thermal expansion and expansion / contraction of the boiler main body without generating a large stress in the steam line. Further, the horizontal branch part 22d of the steam line 22 is composed of a first branch part 23a extending in a radial direction and a second branch part 23b extending in an arc direction, and the first branch part 23a has three rhombic columns 1a, 1b, 1c. The radial steam pipe 20a of one of the rhombic pillars (1a in the figure) communicates with the horizontal part 22c, and the second branch part 23b is horizontally connected to the annular steam pipe 20b of another adjacent rhombic pillar (1c in the figure). Part 22c
And communicates. With such a configuration, the first branch portion 2 is provided in the radial steam pipe 20a and the annular steam pipe 20b of the same rhombic column.
The horizontal portion 22c can be made sufficiently long so as not to overlap with 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 connected to each other. It is possible to more easily follow the thermal expansion and expansion / contraction of the main body.

FIG. 2 shows a second embodiment of the connection structure between the header and the steam pipe according to the present invention, and is similar to FIG. 7 described above. FIG. 3 is an enlarged perspective view of a portion C in FIG. 2 and 3, the connection structure between the header and the steam pipe according to the present invention includes a boiler main body 1 stored in a pressure vessel 4 and forming a fluidized bed therein, and a water pipe wall 12 b forming an outer surface of the boiler main body 1. Steam header 18 provided in parallel to
It is composed of This configuration is the same as 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 (a water pipe near a corner) of the water pipe forming the water pipe wall 12b is formed by the steam header 18.
Is connected to the end face. With such a configuration, the end of the steam header does not protrude 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 up and down and follows this up and down movement. be able to. Further, even if the boiler body expands and contracts due to a pressure difference between the inside and outside of the boiler body, the expansion and contraction can be followed by the horizontal portion being slightly inclined in the horizontal direction. Therefore, according to the present invention, the total length of the horizontal length can be increased even in a narrow space, and it is possible to follow the thermal expansion and expansion / contraction of the boiler main body without generating a large stress in the steam line. Furthermore, the second
According to the configuration described above, the end of the steam header does not protrude 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. Therefore, the connection structure between the header and the steam pipe according to the present invention is capable of following the thermal expansion and expansion / contraction of the boiler main body without generating a large stress, and penetrating the pressure vessel into the steam header for the reheat steam to allow the reheat steam to flow. And the water pipe on 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 the 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 portion C in FIG. 2;

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

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

FIG. 6 is a horizontal sectional view taken along line AA of FIG. 4;

FIG. 7 is another horizontal sectional view having a different height from that of FIG. 6;

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boiler main body 2 Cyclone 3 Bed material storage container 4 Pressure container 5 Evaporator 6 Superheater 7 Reheater 8 Steam header 9 Supporting beam 10 Bottom of boiler main body 11 Ash chute 12a, 12b Water pipe wall 16a, 16b In-layer pipe 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

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F22B 1/02 F22B 37/22 F23C 10/16

Claims (3)

(57) [Claims] 1. A boiler main body that is stored in a pressure vessel and forms a fluidized bed therein, a plurality of low-temperature reheated steam headers provided at the bottom of the boiler main body, and a pressure vessel mounted on the steam header. A boiler body comprising three rhombic pillars adjacent to each other, wherein the steam header is provided on each of the three rhombic pillars, and a rhombic parallel of the rhombic pillars is provided. A pair of radial steam pipes and an annular steam pipe substantially parallel to the two sides, wherein the steam line has a horizontal penetration part penetrating the pressure vessel in the radial direction, a vertical part extending downward from the horizontal penetration part, 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 a radial steam pipe and an annular steam pipe. header And steam pipe connection structure. 2. The horizontal branch of the steam line comprises a first branch extending in a radial direction and a second branch extending in an arc direction, wherein the first branch is formed of one of three rhombic columns. The pressurization according to claim 1, wherein a radial steam pipe communicates with the horizontal portion, and the second branch portion communicates another adjacent rhombic annular steam pipe with the horizontal portion. Connection structure of header and steam pipe in fluidized bed boiler. 3. A steam header which is stored in a pressure vessel and forms a fluidized bed therein, and a steam header provided parallel to a water pipe wall constituting an outer surface of the boiler body, wherein the steam header is provided. The total length of the water pipe wall is shorter than the water pipe wall, a part of the water pipe constituting the water pipe wall is connected to the end face of the steam header, characterized in that the header and the steam pipe in the pressurized fluidized bed boiler characterized in that Connection structure.