JPH0749204Y2 - Boiler furnace wall - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an opening arrangement of a boiler furnace wall, and more particularly to an arrangement of a bottom wall tube suitable for providing an opening in a bottom wall portion of a spiral wall.

<Prior art and its problems> The present invention relates to the tube arrangement of the boiler furnace wall, particularly the furnace bottom wall.

Conventionally, the shape of the furnace bottom wall of a vertical tube type boiler has been a hopper shape.

The reason why the shape of the bottom wall of the furnace is the shape of a hopper is because the residue of the fuel is collected at the bottom of the furnace and processed in a batch.
Alternatively, in gas-fired boilers, the residue is very small, so there is no need to collect it at the bottom of the furnace for treatment, and it is sufficient to occasionally enter the furnace and recover the residue.

In other words, in heavy crude oil and gas fired boilers, it is not necessary to use the conventional hopper type furnace bottom shape, but on the contrary, the boiler height increases, and along with that, materials such as steel frames and furnace wall materials increase, which is uneconomical. .

In recent years, in order to eliminate the above drawbacks, a flat bottom shape, so-called flat hopper, has been used, and even in a spiral wall boiler in which the furnace wall tube is spirally wound upward at an angle close to horizontal, The shape is adopted.

On the other hand, in order to reduce nitrogen oxides and control the reheated steam temperature, a gas recirculation system is used in the boiler to introduce the combustion gas from the economizer outlet back into the furnace.

This method suppresses combustion in the burner zone to reduce nitrogen oxides, and to prevent imbalance in fluid temperature due to uneven flow of combustion gas on the contact heat transfer surface, the gas is fed from the bottom of the furnace to the inside of the furnace. In many cases, the structure will lead uniformly.

Therefore, the bottom of the furnace is required to have an opening for the passage of this gas into the furnace.

In the conventional vertical tube type boiler, this furnace bottom opening can be easily arranged parallel to the vertical furnace wall and over the entire width of the furnace, but in the above flat-hopper spiral wall boiler, the tube pitch is There is a limitation that the parallel arrangement of the tubes makes it possible to eliminate the imbalance in heat absorption between the tubes, and to connect the tubes, so that the so-called membrane bar is burned out.

FIG. 2 shows a conventional embodiment in which an opening is provided in the bottom wall portion of the spiral wall flat hopper.

The bottom wall portion is radially formed by a bottom wall tube 1 bent by α with respect to the furnace wall, and the bottom wall tube 1 is connected to the headers 5 to 7 which are inlets for the fluid inside the tube.

Due to the above-mentioned restrictions, the opening is placed on a virtual line rotated by β = 45 ° -α when viewed from the upper side of the furnace wall with one side pulled from the corner of the furnace wall. I have no choice but to place it.

Moreover, the opening is 1 depending on this angle condition and the number of tubes.
In many cases, the arrangement was divided into two or two.

<Problems to be Solved by the Invention> The above-mentioned conventional technique has the following drawbacks because the opening is divided and the arrangement is rotated with respect to the vertical furnace wall.

(1) When there is only one opening, the bending angle α of the bottom wall tube 1
The size of the opening is determined by and the size cannot be arbitrarily selected, so that the gas passage area corresponding to the amount of recirculated gas cannot be secured.

(2) Since the opening is located at a position rotated with respect to the vertical furnace wall, the flow of recirculated gas becomes unbalanced in the furnace and impairs combustion.

(3) When the opening is divided and provided, the pipe arrangement is complicated.

<Outline of Means> In short, the present invention is a boiler furnace with a rectangular cross section
In a boiler furnace wall where 12 is made almost horizontal and a spiral wall is formed from the furnace bottom to a vertical furnace wall, a square opening 11 is formed in the furnace bottom.
Is provided parallel to the vertical furnace wall, and the two opposite corners 10 of the rectangular opening are separated from the corner 9 of the furnace wall 8 (45 °-
α) Positioned on imaginary lines 2 rotated by an angle, the bottom wall portions of the spiral wall are constituted by bottom wall pipes 1 bent at an angle α with respect to the vertical furnace wall when viewed from above the furnace wall, and The tube 1 is on the imaginary line 2 extending from each corner 9.
It is a boiler furnace wall characterized by being formed so as to bend at 90 °.

<Purpose of the Invention> This invention proposes an arrangement and structure of a bottom wall pipe for making the bottom of a furnace having a spiral wall almost horizontal, and making its opening one and to locate it at the center of the bottom of the furnace. To aim.

<Embodiment 1> An embodiment of the present invention is shown in FIG. 1, and the arrangement of the bottom wall tube according to the present invention will be described below.

The bottom wall portion of the spiral wall of the boiler furnace wall is composed of a bottom wall pipe 1 bent by α with respect to the vertical furnace wall when viewed from the top of the furnace wall, and the bottom wall pipe 1 is a header 5 which is an inlet for internal fluid. ~ 7
Connected with.

The opening of the bottom wall is installed parallel to the vertical furnace wall, and the corner of the opening is drawn from the corner of the vertical furnace wall.
Place on virtual line 2 rotated by 45 ° -α.

The contents of the embodiment of the invention described above will be described in more detail.

The bottom wall portion of the spiral wall is configured to be flat by rotating the tube groups welded to each other in an airtight manner by an angle α from the upper portion of the vertical furnace wall.

This bottom wall tube 1 extends linearly until it intersects with an imaginary line 2 rotated by β = 45 ° -α when viewed from the upper portion of the vertical furnace wall drawn from the corner of the vertical furnace wall, and after the intersection, bends 90 °. Then, this is repeated until reaching the periphery 3 and 4 of the opening to form the bottom wall and the opening.

Further, the openings are arranged so that their corners are provided on the imaginary line and are parallel to the vertical furnace wall.

The pipe header connected to the bottom wall pipe 1 is arranged so as to be parallel to the periphery of the opening.

The following effects can be obtained by adopting the embodiment of this invention.

(1) By arranging the corners of the opening on the imaginary line 2, an opening of any size can be selected.

(2) Since the opening is installed parallel to the vertical furnace wall, the flow of recirculated gas becomes uniform in the furnace.

(3) The pipe arrangement can be simplified because it is installed parallel to the peripheral wall of the opening.

(4) Since the length of the pipes forming the bottom wall can be made almost uniform without changing from the conventional structure, the temperature difference between the individual pipes can be reduced,
A uniform heat absorption can be achieved.

<Effect> By implementing the present invention, by arranging the corners of the opening on a virtual line drawn from the corner of the vertical furnace wall and by arranging the opening parallel to the vertical furnace wall, the following effects can be obtained. Is obtained.

(1) It is possible to form one opening of an arbitrary size, and since the opening is provided so as to be parallel to the boiler furnace wall, the flow of recirculated gas becomes uniform in the furnace.

(2) Since the furnace wall tubes can be made almost uniform in length, the temperature difference between the tubes can be reduced, uniform heat absorption can be achieved, and the tube arrangement can be simplified, resulting in an economical boiler design. Can be achieved.

This effect is particularly great.

(3) Since the furnace wall is horizontal, the height of the furnace can be reduced and the cost of furnace equipment and supporting steel frame can be saved.

[Brief description of drawings]

FIG. 1 is a plan view of a bottom wall of a first embodiment of the present invention, and FIG. 2 is a plan view of a conventional bottom wall. 1 ... Bottom wall tube, 2 ... Virtual line 3, 4 ... Circumferential wall of opening 5, 6, 7 ... Pipe alignment, 8 ... Furnace wall 9 ... Corner, 10 ... Corner of opening 11 …… Opening part, 12 …… Floor bottom

Claims (1)

[Scope of utility model registration request] 1. A boiler furnace wall in which a furnace bottom (12) is substantially horizontal in a boiler furnace having a rectangular cross section and a spiral wall is formed from the furnace bottom to a vertical furnace wall, and a square opening (11) is formed in the furnace bottom. Imaginary line in which two edges (10) of the square-shaped opening facing each other are provided in parallel with the vertical furnace wall and the corner (9) of the furnace wall (8) is rotated by (45 ° -α) angle. (2) The bottom wall portions of the spiral walls, which are respectively located above, are constituted by bottom wall pipes (1) bent at an angle α with respect to the vertical furnace wall when viewed from above the furnace wall, and the bottom wall pipes (1) ) Is a boiler furnace wall characterized in that it is formed so as to bend at 90 ° on the virtual line (2) extending from each corner (9).