JP3346494B2 - Hexagonal pressurized fluidized bed boiler trifurcated duct - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flue gas duct for a fluidized-bed boiler, and more particularly to a three-pronged tact for a hexagonal pressurized fluidized-bed boiler.

[0002]

BACKGROUND ART pressurized Doso boiler for flowing burning coal under pressure may have 40% or more thermal efficiency combined cycle in combination with a gas turbine, high furnace desulfurization rate, generate less of the NO _x Because of these features, it is currently being developed as a new type of boiler that replaces the conventional powder-fired boiler.

FIG. 5 is an overall structural view of a hexagonal pressurized fluidized-bed boiler (hereinafter, referred to as a hexagonal fluidized-bed boiler) in which the boiler body 1 has the form of a hexagonal prism. A boiler body 1, a cyclone 2, a bed material storage container 3, an exhaust gas duct 5, and the like are configured to be stored in a pressure vessel 4, and coal supplied from the outside is burned in the boiler body 1, and the coal is discharged through the exhaust gas duct 5. The exhaust gas from which the ash has been removed by the cyclone 2 is supplied to an external gas turbine (not shown) for power generation and the like. The steam generated in the boiler main body 1 performs work such as power generation by an external steam turbine (not shown).

FIG. 6 is a perspective view of a boiler main body 1 of a hexagonal fluidized bed boiler. The boiler main body 1 has three rhombic columns 1a, 1
b, 1c are configured adjacent to each other, and there is no partition inside,
Each surface of the hexagonal column is composed of a water pipe wall, and three rhombic columns 1a, 1
On the upper surfaces of b, 1c, diamond-shaped ceiling wall openings 6a, 6b, 6c
Exhaust gas from the boiler is discharged from the ceiling wall openings 6a, 6b, 6c and sent to the exhaust gas duct 5, and a later-described inner layer pipe inside the boiler is taken out for repair.

FIG. 7 is a horizontal sectional view taken along line AA of FIG. The boiler main body 1 has a hexagonal horizontal section, and includes six vertical furnace walls 12a and 12b and a hexagonal closed back stay 14. The inside of the hexagon is
3 virtual dash-dot lines 120 ° apart from the center
Is divided into two spaces. That is, the interior of the hexagon is formed of three parallelograms having a horizontal cross section in which two adjacent furnace walls 12a and 12b are defined as two sides of a parallelogram. In each space, a first in-layer tube group 16 whose one end is adjacent to one furnace wall 12a and adjacent to the other furnace wall 12b, and whose vertical planes are parallel to each other.
a, one end of which is adjacent to the other end of the first in-layer tube group 16a and which is parallel to one of the furnace walls 12a and which is vertically parallel to each other.
And the in-layer tube group 16b.

FIG. 8 is a sectional view of the tube group 16a, 16 in FIG.
FIG. 4 is a side view of an inner layer tube 20 constituting b. The in-layer tube 20 is attached to a support tube 18 suspended from above in the boiler body 1, and includes an evaporating tube 21 for evaporating water, a superheating tube 22 for heating steam to a high temperature, and reheating a low-temperature steam. And a reheating tube 23. As described above, this inner tube 2
0 is taken out from the flange 5b above the exhaust gas duct 5 shown in FIG. 5 through the diamond-shaped ceiling wall opening 6 shown in FIG.

[0007]

In FIG. 5, an exhaust gas duct 5 has three connecting ducts 5c connected to three ceiling wall openings 6a, 6b, 6c, joined at a forked portion 5a and connected to a cylindrical duct 5d. ing. When the ceiling wall opening 6 is rhombic, the shape of the trifurcation 5a connecting three rhombuses and connecting them in a cylindrical shape becomes simple, but the trifurcation duct is enlarged without interfering with the support pipe 18 of the in-layer tube group. It was difficult. In addition, the ceiling wall opening 6 is preferably as large as possible for taking out the inner layer pipe 20, and is preferably closer to the center of the boiler main body 1. For this reason, an oval or elliptical opening is desirable, but the shape of the duct is also an ellipse or ellipse, and the shape of the forked portion 5a becomes more difficult.

The present invention has been made in view of the above-mentioned problems, and can cope with a change in the position and shape of the ceiling wall opening 6 and the structure of the three-forked portion 5a and the three-forked portion 5a.
It is an object of the present invention to provide a simple three-pronged duct having a duct structure up to.

[0009]

In order to achieve the above object, a three-pronged duct is provided which connects an opening of a ceiling wall of a boiler which is housed in a pressure vessel and forms a fluidized bed therein and a cylindrical duct provided at an upper portion thereof. The ceiling wall is formed of three regular rhombic hexagons, each of which has a hexagonal ceiling wall opening, and the trifurcated duct is connected to the cylindrical duct by a trifurcated portion. A connecting duct connecting the lower part of the fork and the ceiling wall opening, the lower horizontal section of the fork forms a regular hexagon on one side a, and the regular hexagon is disposed along every other side. Are divided into three long hexagons, a first triangle formed at the center of the regular hexagon by arranging the long hexagons, and a second triangle formed by sharing a vertex for each vertex of the first triangle. And the long hexagon is And two long sides side length opposite the a, side length is composed of a four sides of a / 3, each apex angle of 12
0 °, one long side of the long hexagon is arranged inside the regular hexagon so as to coincide with one side of the regular hexagon, and the first triangle and the second triangle are closed, The trifurcated portion connects the lower horizontal section and the cylindrical duct with a flat plate and a curved plate, and the connection duct makes the long hexagons of the lower horizontal section correspond to the ceiling wall openings, respectively. , And the corresponding sides are connected by a flat plate.

The first triangular portion is formed by a triangular pyramid having an apex at an upper portion, and the second triangular portion is provided with a ridge line at an upper portion and has a slope inclined to an adjacent long hexagon. It is composed.

[0011]

The hexagonal ceiling wall opening is provided in each of the three diamonds on the ceiling wall of the boiler body. On the other hand, a regular hexagon having one side a is formed at a position where the trifurcated duct is formed. A long hexagon is formed every other side of the regular hexagon.
The long hexagon has the same two sides as the side of the regular hexagon.
The length of the other four sides is a / 3, and the apex angle is 120 °, which is a hexagon. This long side a is made to match the side length a of the regular hexagon,
Place the long hexagon inside the regular hexagon. When arranged in this manner, as shown in FIG. 3, three long hexagons are arranged along each side of the regular hexagon, and a first triangle of a regular triangle having a side length a at the center and this first triangle A second triangle of an equilateral triangle having the side length a / 3 and having the same vertex at each vertex is formed. Each long hexagon and each ceiling wall opening correspond to each other, and the corresponding sides are connected by a plate constituting a duct. In this case, if the corresponding sides are parallel, the duct plate stretched there may be a single plane, but if they are not parallel, it will be composed of two planes with one diagonal broken. Further, since the regular hexagon is almost circular, the structure of the connection portion with the cylindrical duct is simplified. As a result, a three-junction duct having a simple structure of the junction of the three ducts connected to the ceiling wall opening and the connection with the cylindrical duct is realized. In addition, since the relative position between the long hexagon and the ceiling wall opening can be freely determined, the position of the ceiling wall opening can be determined in consideration of handling of the in-layer pipe.

Since the first triangular portion is constituted by a triangular pyramid having an apex above, and the second triangular portion is constituted so as to have a ridge line at the top and to have a slope inclined to an adjacent long hexagon. Accumulation can be prevented.

[0013]

Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a three-pronged duct according to an embodiment of the present invention, and FIG. 2 is a side view. FIG. 3 is a diagram showing the size and shape of the junction of the three ducts, and FIG. 4 is a diagram showing the arrangement of the ceiling wall opening 6 of the boiler ceiling wall. As shown in FIG. 4, the ceiling wall opening 6 is hexagonal and each of the rhombic columns 1a, 1b, 1
It is provided substantially at the center of the upper surface of c, but its position is determined so that lateral movement is reduced in consideration of taking out of the inner layer tube 20.

FIG. 3 shows the shape of the junction of the three ducts. The inside of a regular hexagon 7 having one side length a is divided into three long hexagons 8a, 8b, 8c, a first triangle 9 positioned at the center, and a second
It is divided into triangles 10a, 10b, 10c. Long hexagon 8
Represents the length of two opposing sides as a and the length of the other four sides as a
/ 3, and a hexagonal shape with each apex angle of 120 °. The long side a is aligned with one side of the regular hexagon 7 and arranged inside the regular hexagon 7. Long hexagons 8a, 8b, 8 every other side of regular hexagon 7
When c is arranged, the remaining shapes become the first triangle 9 and the second triangles 10a, 10b, 10c. The first triangle 9 is an equilateral triangle having a side length a, and the center of gravity coincides with the center of the equilateral hexagon 7. The second triangle 10 is a regular triangle having a side length of a / 3, and exists at each vertex of the first triangle.

In FIG. 1, the upper left portion is a ceiling wall opening 6b.
And the position and dimensional relationship of the long hexagon 8b. Both are hexagonal, but all apex angles are different. However, dimensions of A and A 'and dimensions of B and B' are respectively equal and parallel. The other four sides have different dimensions and are not parallel. The first triangle 9 constitutes a triangular pyramid having a vertex at the top, the second triangle 10 has a ridge at the center, and is constituted to have a slope inclined to the left and right long hexagons 8,
Each has a structure to prevent ash accumulation.

When the corresponding sides of the ceiling wall opening 6b and the long hexagon 8b are connected to form a duct surface, the number of surfaces which are not formed as one plane and have broken lines increases. Therefore, as shown in FIG. 2, the ceiling wall opening 6b is inclined with the side A 'as an axis, and is constituted by a duct surface composed of an inclined surface and a vertical surface. Reference numeral 30 denotes a duct surface connecting the long side C of the long hexagon 8 and the long side C ′ of the inclined ceiling wall opening 6. Although they are not parallel in the plan view of FIG. 1, they can be made one plane by being inclined. Reference numeral 30 'denotes a duct surface connecting one side of the first triangle 9 and the long side C''of the inclined ceiling wall opening 6, and is similarly constituted by one plane. In this way, each surface constituted by the long sides of the long hexagon 8 is constituted by one surface.

Reference numeral 31 denotes a duct surface connecting the side D of the long hexagon 8 and the side D 'of the inclined ceiling wall opening 6, and is composed of two surfaces including a broken line. Reference numeral 31 'denotes a duct surface connecting the side E of the long hexagon 8 and the side E' of the inclined ceiling wall opening 6,
It is composed of two surfaces with a broken line. Numeral 32 denotes a duct surface connecting the side B of the long hexagon 8 and the side B 'of the inclined ceiling wall opening 6, and is constituted by one plane because it is parallel. 32 'is a single plane because it is parallel to a duct surface connecting the side A of the long hexagon 8 and the side A' of the ceiling wall opening 6.

Reference numeral 5d denotes a cylindrical duct which constitutes the upper duct of the three-pronged duct. 34 is a cylindrical duct 5d and a regular hexagon 7
Is an arc-shaped triangular plate connecting the cross sections of FIG. Reference numeral 35 denotes a planar triangular plate connecting the cross section of the cylindrical duct 5d and the regular hexagon 7.

Although the above embodiment shows a case where the ceiling wall opening 6 and the long hexagon 8 are parallel and the same length on two sides, there may be no parallel side. Further, although the ceiling wall opening 6 has a long hexagon in which two opposing sides are longer than the other four sides, there is no need to make such a configuration, and a hexagon may be used.

[0020]

As is apparent from the above description, the present invention, if the ceiling wall opening of the boiler is formed in a hexagonal shape, does not take into account much of the connection with the duct side, so that the requirements for the ceiling wall opening can be satisfied. Therefore, the shape and position may be optimally selected in terms of strength, performance, and work, thereby increasing the degree of freedom in design. In addition, the surface of the duct connecting the regular hexagonal cross section of the junction and the opening of the ceiling wall can be constituted by one surface for each of the four sides of the hexagon, and each of the remaining two sides is provided with a polygonal line. , Which facilitates design and manufacture. Further, the connection between the regular hexagonal cross section of the junction and the cylindrical duct can be achieved by simply arranging arc-shaped triangular plates and flat-plate triangular plates alternately, so that the structure is simple. As described above, the present invention realizes a three-pronged duct having a large degree of design freedom and a simple structure.

[Brief description of the drawings]

FIG. 1 is a plan view of the present embodiment.

FIG. 2 is a side view of the present embodiment.

FIG. 3 is a diagram illustrating a shape of a merging portion of three ducts.

FIG. 4 is a diagram showing an arrangement of ceiling wall openings.

FIG. 5 is an overall structural view of a hexagonal pressurized fluidized bed boiler.

FIG. 6 is a perspective view of a boiler main body of a hexagonal pressurized fluidized bed boiler.

FIG. 7 is a horizontal sectional view taken along line AA of FIG. 5;

FIG. 8 is a side view of the inner layer tube.

[Explanation of symbols]

Reference Signs List 1 boiler main body 1a, 1b, 1c rhombic column 4 pressure vessel 5 exhaust gas duct 5a trifurcation 5b flange 5c connecting duct 5d cylindrical duct 6a, 6b, 6c ceiling wall opening 7 regular hexagon 8a, 8b, 8c long hexagon ninth 1 triangle 10a, 10b, 10c 2nd triangle 12a, 12b Furnace wall 14 Back stay 16a, 16b In-layer tube group 18 Support tube 20 In-layer tube 21 Evaporation tube 22 Superheater tube 23 Reheat tube 30, 30 ', 31, 31' , 32, 32 'Duct surface connecting the long hexagon and the ceiling wall opening 34 Arc-shaped triangular plate 35 Planar triangular plate A, B, C, D, E Long hexagonal sides A', B ', C', D ', E' Side of ceiling wall opening a Side length of regular hexagon

Claims (2)

(57) [Claims] 1. A three-junction duct for connecting an opening of a ceiling wall of a boiler which is housed in a pressure vessel and forms a fluidized bed therein and a cylindrical duct provided on an upper portion thereof, wherein the ceiling wall has a substantially regular hexagonal shape. The rhombus is provided with a hexagonal ceiling wall opening, and the truncated duct is connected to the cylindrical duct, and a truncated portion is connected to a lower portion of the truncated portion and the ceiling wall opening. The lower horizontal section of the trifurcation forms a regular hexagon on one side a, and the regular hexagon includes three long hexagons arranged along every other side and this long hexagon. The first hexagon is divided into a first triangle generated at the center of the regular hexagon by arranging the polygon, and a second triangle generated with a common vertex for each vertex of the first triangle. Are two opposite long sides of a, and the side Is constituted by four sides of a / 3, each apex angle is 120 °, and one long side of the long hexagon is arranged inside the regular hexagon so as to coincide with one side of the regular hexagon. The first triangle and the second triangle are closed; the trifurcation is formed by connecting the lower horizontal section and the cylindrical duct with a flat plate and a curved plate; A triangular duct for a hexagonal pressurized fluidized-bed boiler, wherein each of the long hexagons in cross section corresponds to the ceiling wall opening, and the corresponding sides are connected by a flat plate. 2. The first triangular portion is constituted by a triangular pyramid having an apex at an upper portion, and the second triangular portion is provided with a ridge line at an upper portion and has a slope inclined to an adjacent long hexagon. The three-pronged duct of a hexagonal pressurized fluidized bed boiler according to claim 1, wherein the duct is constituted.