JP2001012702A - Downcast pipe structure for circulating type boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify structure and remove limitation in installation of downcast pipes by obliquely providing a corner heat receiving panel at a corner of a furnace in which the wall surface consist of furnace wall pipes and permitting the furnace wall pipes as the corner which is shut out by the corner heat receiving panel to communicate with liquid in a steam separating drum so as to be used as downcast pipes. SOLUTION: A corner heat receiving panel 15 is provided so as to bridge the corner made by a wall surface 2 and another adjacent wall surface 2, and a heat insulating material 18 is provided at the back surface of the panel, so that the portion of a triangle including the panel 15 as its leg is physically and thermally shut out from the inside of a furnace 1. Furnace wall pipes 16 of the panel 15, as well as furnace wall pipes 3 of the wall surface 2, communicate with a steam separating drum from the upper portion by way of an upper header, and the lower end communicates with downcast pipes 20 by way of a lower header. Thus the downcast pipes are not required to be separately provided, and hence only a small space is needed for the installation and it is not necessary to consider connection with other structure such as a steel frame and the like. As a result, the structure can be simplified, the thickness of the piping can be reduced, and also, the weight can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a downcomer structure for a circulation boiler.

[0002]

2. Description of the Related Art Conventionally, a circulation type boiler in which boiler water is naturally circulated or forcedly circulated has been used in thermal power generation equipment and the like. An example of a circulation boiler will be described with reference to FIG.

[0003] In the figure, reference numeral 1 denotes a furnace. The furnace 1 has a rectangular cross section in plan view, and front, rear, left and right wall surfaces 2 of the furnace 1 are formed by furnace wall tubes 3. A steam / water separation drum 4 is provided at the upper part of the furnace 1, and a water supply pipe 11 communicates with a liquid portion 5 of the steam / water separation drum 4, and water heated from outside via the water supply pipe 11 is provided. The furnace wall tube 3 communicates with the separation section 6 of the furnace 1 via an upper header 7, and the furnace wall tube 3 is connected to a lower header 8 at a lower portion of the furnace 1. Is in communication with

[0004] A plurality of downcomers 9 communicate with the liquid part 5,
The downcomer 9 descends outside the furnace 1 to form a horizontal portion 9 a at the lower part of the furnace 1. The horizontal portion 9a and the lower header 8 are communicated by a communication pipe 10.

The steam S taken out of the steam / water separation drum 4 is guided to a superheater (not shown) through a ceiling wall 12.

In the above-mentioned circulation type boiler, boiler water rises and is heated in the furnace wall tube 3, and heated water containing steam is guided to the steam separator drum 4 and boiler water W and steam S
The steam S taken out is supplied to the ceiling wall 12 and then guided to a superheater (not shown), and the boiler water W in the steam separator 4 descends through the downcomer 9. ,
The heat is supplied to the furnace wall tube 3 again through the horizontal portion 9a and the lower header 8, and heating is performed.

[0007]

The downcomer 9 lowers the boiler water W from which the steam S has been separated by the steam separator 4, and the flow required for lowering the separated boiler water W. It requires a road cross-section and maintains a high temperature and high pressure. Therefore, the downcomer 9 is a large-diameter, thick-walled pipe, is heavy, and is provided independently outside the furnace 1, so that a space for installing the pipe is required and a burner, a supporting steel frame, and the like are required. The support structure became complicated due to the involvement with other structures. For this reason, there has been a problem that the equipment cost is increased and the installation space of the entire boiler is increased.

The present invention has been made in view of the above circumstances, and aims at simplifying the structure of the downcomer pipe structure of a circulation boiler, eliminating restrictions on the construction of downcomer pipes, reducing costs, and further saving installation space. is there.

[0009]

According to the present invention, a corner heat receiving panel is provided diagonally at a corner of a furnace whose wall is formed by a furnace wall tube, and the furnace at the corner shielded by the corner heat receiving panel is provided. The present invention relates to a downcomer structure of a circulating boiler in which a wall tube is used as a downcomer by communicating with a liquid portion of a steam separator, and the corner heat receiving panel is formed by connecting a furnace wall tube to a rear side. It is related to the downcomer structure of a circulation type boiler equipped with heat insulating material.Since a part of the furnace wall of the furnace is used as the downcomer, there is no need to provide a separate downcomer, and the layout is restricted. In addition, since the diameter of the pipe used as the downcomer is reduced, the wall thickness can be reduced and the weight can be reduced.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 both show a corner portion of the furnace 1. In FIG. 1, the same components as those shown in FIG. 3 are denoted by the same reference numerals, and the description of the common portions will be omitted.

A corner heat receiving panel 15 is provided to extend over a corner between adjacent wall surfaces 2. The corner heat receiving panel 15 is formed by connecting a furnace wall tube 16 with heat receiving fins 17 and has the same structure as the wall surface 2. On the back side (inside of the furnace) of the corner heat receiving panel 15, a heat insulating material 18 such as rock wool or glass wool is provided.

By providing the corner heat receiving panel 15 and the heat insulating material 18, the corners of the wall surfaces 2, 2 constituting the other two sides of the triangle having the corner heat receiving panel 15 as the hypotenuse, ie, the rain panel 1.
9 and 19 are physically and thermally shielded from the inside of the furnace 1 by the corner heat receiving panel 15 and the heat insulating material 18. The furnace wall tube 3 included in the rain panel 19 functions as a down tube 20. The downcomer 9 conventionally provided is omitted. Therefore, the number of the downcomers 20 and the inner diameter of the downcomers 20 are set so that the total of the cross-sectional areas of the downcomers 20 is at least equal to the total of the cross-sectional areas of the downcomers 9 in the related art.

The furnace wall tube 16 of the corner heat receiving panel 15 is
Like the furnace wall tube 3 of the wall surface 2, the upper part communicates with the steam separator drum 4 via the upper header 7, and the lower end communicates with the downcomer pipe 20 via the lower header 8.

The upper end of the downcomer 20 is communicated with the liquid part 5 of the steam separator 4, and the lower end is communicated with the lower header 8.

By providing the corner heat receiving panel 15,
Since the heat received by the two precipitation panels 19 is received by the corner heat receiving panel 15, the corner heat receiving panel 15 is received.
Is assumed to be a right-angled isosceles triangle, the heat receiving area is reduced to approximately 70%. However, the conventional furnace wall tube 3 at the corner has a low capability as an evaporating tube, and the corner heat receiving panel 15 makes the corner heat receiving panel 15 itself more susceptible to heat from inside the furnace. The evaporation capacity of the panel 15 does not decrease to 70%. Further, in order to secure the heat receiving area, the horizontal length of the wall surface 2 may be increased, and the increased dimension is such that there is almost no problem when viewed from the furnace 1 as a whole.

In FIG. 1, reference numeral 22 denotes a back stay, which is a strength member for supporting an internal pressure or the like acting on the wall surface 2.

The operation will be described below.

As described above, the heat from the inside of the furnace is cut off by the corner heat receiving panel 15 and the heat insulating material 18, and the precipitation panels 19, 19 are not directly heated from inside the furnace.

The boiler water rising in the furnace wall tube 16 is separated into steam and water in the separation section 6, and the separated steam is separated from the ceiling wall 12.
And sent to a superheater (not shown) (see FIG. 3).

The heated water separated by the steam separation is stored in the liquid part 5, descends through the downcomer 20, and rises and circulates through the lower wall 8 through the furnace wall tube 3.

Although the heat from the furnace is cut off from the hot water flowing down the downcomer 20, the circulating boiler water is saturated water as a whole. There is no temperature difference from the temperature of the boiler water rising through the furnace wall tube 16 and the furnace wall tube 3, and the rain panel 19 and the wall surface 2,
Although it is continuous with the corner heat receiving panel 15, no thermal load such as thermal stress occurs at the boundary.

Since there is no need to separately provide the downcomer 9 as in the prior art, the installation space is small, and there is no need to consider the connection with other structures such as a burner and a supporting steel frame. It is simpler, and furthermore, a smaller pipe may be used as compared with the conventional downcomer 9, so that the wall thickness may be thinner and the weight may be reduced.

The corner heat receiving panel 15 does not need to be provided at four corners, but may be provided at three corners or at two corners, as long as it can secure a flow rate corresponding to the amount of hot water falling. Furthermore, the downcomer 20 and the furnace wall tube 3 do not necessarily have to have the same dimensions.

[0025]

As described above, according to the present invention, there is no need to separately provide a downcomer, so that the installation space is reduced, and there is no need to consider the connection with other structures such as burners and supporting steel frames. , The structure is simple, and the pipe may be smaller than the conventional downcomer 9 so that the wall thickness may be thinner.
It has an excellent effect that the weight can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a partial plan view showing the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace 2 Wall surface 3 Furnace wall tube 4 Steam separator drum 15 Corner heat receiving panel 16 Furnace wall tube 18 Heat insulation material 19 Rainfall panel 20 Rainfall tube

Claims (2)

[Claims] At least one corner heat receiving panel is provided diagonally at a corner of a furnace where a wall surface is formed by a furnace wall tube, and the furnace wall tube at a corner shielded by the corner heat receiving panel is connected to a steam separator drum. A downcomer structure of a circulation boiler, characterized in that it is used as a downcomer in communication with the liquid part. 2. The downcomer structure of a circulation type boiler according to claim 1, wherein said corner heat receiving panel is constituted by connecting furnace wall tubes in series, and a heat insulating material is provided on the back side.