JPH08334208A - Temperature lowering structure of heat transfer panel support member - Google Patents

Abstract

PURPOSE: To provide a temperature lowering structure of a heat transfer panel support member which enables thermally expanding of a heat transfer panel smoothly under a high temperature and a light surface pressure by lowering the temperature of a support member for supporting the heat transfer panel to eliminate diffusion or coupling of a stick slip with a lowering of the degree of high temperature oxidation of a slide surface. CONSTITUTION: This temperature lowering structure is provided with a panel support part 12 having a horizontal undersurface provided closely on the under side of a lower header 5b of a heat transfer panel, a hollow frame base 14 having a horizontal top surface to support the panel support part on the top surface, a water supply introduction line 16 to introduce a part of water supplied to the lower header and a water supply/drain line 18 to let supply water flow to the lower header from the hollow base. The panel support part 12 and the hollow frame base 14 are cooled by the water supplied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust heat recovery boiler, and more particularly to a structure for reducing the temperature of a heat transfer panel supporting member in the exhaust heat recovery boiler.

[0002]

2. Description of the Related Art A combined cycle in which a Brayton cycle and a Rankine cycle are combined, and repowering in which an output is increased by combining a gas turbine with an existing boiler,
It has become more and more popular in recent years. FIG. 4 is an overall configuration diagram of an exhaust heat recovery type combined cycle power generation plant which is one of combined cycles, in which exhaust gas of a gas turbine 1 is guided to an exhaust heat recovery boiler 2 (HRSG: Heat Recovery Steam Generator) and its heat is recovered. Is recovered to generate steam to drive the steam turbine 3. This combined cycle takes advantage of the high maximum utilization temperature of the gas turbine and the low minimum utilization temperature of the steam turbine.It has high thermal efficiency and partial load efficiency, short start-stop time, and hot drainage volume. There are few The exhaust heat recovery boiler shown in FIG. 4 is also applied to repowering to recover the exhaust heat of the gas turbine.

FIG. 5 is an overall configuration diagram of a conventional exhaust heat recovery boiler. As shown in this figure, a conventional exhaust heat recovery boiler includes a boiler main body 4 lined with a heat insulating material, and a plurality of (three in this figure) vertically mounted on a frame 4a inside the main body. It consists of heat transfer panel 5 and each heat transfer panel 5
Consists of upper and lower horizontal headers 5a, 5b (manifolds) and a large number of vertical heat transfer tubes 5c connecting the headers. Inside the boiler main body, the partition plate 4b partitions the high-temperature exhaust gas (for example, 650 ° C.) from the gas turbine (from left to right in this figure) into the exhaust gas flow path and the storage portion for the vertical alignment, and the horizontal alignment. Are not directly exposed to hot exhaust gases. In addition, a panel support portion 6 is provided below the lower header 5b.
It is supported by a and supports the weight of the heat transfer panel. In addition, boiler feed water sequentially flows upward from the downstream side to the vertical heat transfer tubes 5c of each heat transfer panel 5 and is heated by high temperature exhaust gas to become high temperature water or steam, thereby recovering heat in the exhaust gas. There is.

FIG. 6 is a panel front view of a conventional large-sized exhaust heat recovery boiler. The exhaust heat recovery boiler shown in this figure has a large size, and the cross section of the flow path of the high-temperature gas is, for example, about 10 m × 10 m, and the weight of each heat transfer panel arranged in parallel in the flow path is 2
It reaches 0 to 30 tons. The basic structure of each part is shown in FIG.
Is the same as

[0005]

In the above-described conventional exhaust heat recovery boiler, the heat transfer panel thermally expands (or contracts) in the width direction at the time of starting or stopping, so that the panel support portion 6 moves above the pedestal 4a. You need to slide horizontally. However, around the pedestal 4a, high temperature exhaust gas (about 65
(0 ° C) flows in, the sliding surface of the gantry 4a becomes almost the same high temperature, the coefficient of sliding friction after holding for a long time greatly increases (for example, 2 or more), and stick slip and partial diffusion coupling occur. And the heat transfer panel 5 is mounted on the mount 4a.
(Heat transfer panel support member) There is a problem that it does not slide smoothly.

Therefore, an excessive horizontal force (for example, about 40 to 60 tons, which is more than twice its own weight) acts on the heat transfer panel due to an increase in the friction coefficient and diffusion coupling, and the temperature rises and cools due to the stick slip. In the process, the thermal expansion is suddenly released, and a violent impact load is applied along with the impact sound of a dawn, which may cause cracks or the like in each part.
This phenomenon occurs even in a relatively small heat recovery steam generator, but it becomes more important as the size becomes larger.

The sliding surface of the above-mentioned mount is, for example, about 650.
While being exposed to a high temperature of ℃ or more, it receives a high surface pressure of 50 to 70 Kg / cm ² . Therefore, the above-mentioned phenomenon cannot be avoided with ordinary materials, and conventionally, for example, the heat transfer panel is divided in the width direction (see FIG. 5), the strength of each part of the boiler is increased, and frequent maintenance is performed. Was taken. However, due to these measures, there are problems that the structure becomes complicated, the weight increases, the device becomes large, and the manufacturing cost becomes excessive.

The present invention was devised to solve such problems. That is, the object of the present invention is to reduce the temperature of the supporting member that supports the heat transfer panel, thereby reducing the high temperature oxidation amount of the sliding surface, eliminating stick slip and diffusion coupling, and performing heat transfer at high temperature and high surface pressure. An object of the present invention is to provide a structure for reducing the temperature of a heat transfer panel support member that can smoothly thermally expand the panel.

[0009]

According to the present invention, there are provided a plurality of heat transfer panels vertically arranged in a boiler body and arranged at intervals along a horizontally flowing exhaust gas,
Each of the heat transfer panels is a structure for reducing the temperature of a heat transfer panel support member in an exhaust heat recovery boiler, which includes upper and lower horizontal heat transfer panels and a plurality of vertical heat transfer tubes connecting the horizontal heat transfer panels.
A panel support portion that is provided in close contact with the lower surface of each of the lower pipe headers and that has a horizontal lower surface, a hollow pedestal that has a horizontal upper surface that supports the panel support portion, and one of the water supplies to the lower pipe headers. There is provided a temperature reduction structure for a heat transfer panel support member, comprising: a water supply introduction line for introducing a portion into a hollow gantry; and a water supply discharge line for flowing water from the hollow gantry to a lower pipe header. .

According to a preferred embodiment of the present invention, the upstream end of the water supply introduction line communicates with a downfall pipe or a water supply pipe.

[0011]

According to the above-described structure of the present invention, the frame for supporting the heat transfer panel is hollow, and a part of the water supply to the lower header is supplied from the water supply introduction line to the inside of the frame. Thus, the hollow frame can be cooled, and the upper surface and the lower surface of the panel support can be directly cooled by heat transfer. Further, since the panel support portion of the heat transfer panel is provided in close contact with the lower surface of each lower pipe header, the panel support portion can also be cooled by heat transfer from the lower pipe header filled with water. That is, the temperature of the water supplied to the lower pipe is sufficiently lower than that of the exhaust gas (for example, 200 to 300 ° C.). Therefore, by cooling the hollow pedestal and the panel support by this water, the sliding surface located between them, that is, The upper surface of the hollow pedestal and the lower surface of the panel support are cooled to a temperature at which high-temperature oxidation is unlikely to occur (for example, about 350 to 400 ° C), thereby eliminating stick slips and diffusion coupling, and making the heat transfer panel under high temperature and high surface pressure. The horizontal extension can be smoothed.

Further, according to the preferable construction of the present invention, since the upstream end of the water supply introduction line is communicated with the downfall pipe or the water supply pipe to the lower head, it is possible to provide a high temperature pump or the like, Due to the self-circulation of the water supply flowing between the heat transfer panels, relatively low temperature water supply can be made to flow through the water supply introduction line and the water supply discharge line.

[0013]

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. 1 is an overall configuration diagram of an exhaust heat recovery boiler having a temperature reduction structure for a heat transfer panel support member according to the present invention, and FIG. 2 is a panel front view of the exhaust heat recovery boiler of FIG. 1 and 2, the exhaust heat recovery boiler 10 includes three heat transfer panels 7 in a boiler body 4.
The heat transfer panels 8 and 9 are vertically arranged and are arranged at intervals along the horizontally flowing exhaust gas. Each heat transfer panel is composed of upper and lower horizontal heat transfer tubes 5a and 5b (manifolds) and a large number of vertical heat transfer tubes 5c connecting the horizontal heat transfer panels.

Further in FIG. 1, the heat transfer panels 7, 8 and 9 are shown.
Between the upper side 5a on the downstream side and the lower side 5 on the upstream side.
A downcomer 11a for supplying water is provided in b. Further, low-temperature (about 180 to 200 ° C.) feed water is externally supplied to the bottom pipe 5b of the heat transfer panel 9 located at the most downstream side from the feed water inlet line 11b.
The uppermost heat transfer panel 7 introduced from
From a, steam or high-temperature water having a high temperature (for example, 300 ° C. or higher) is supplied to a main boiler or the like (not shown) via the water supply outlet line 11c. Such a configuration is similar to that of the conventional exhaust heat recovery boiler shown in FIG.
The present invention is not limited to the three heat transfer panels, and may be two or four or more.

FIG. 3 is an enlarged view of portion A of FIG. 2, showing a structure for reducing the temperature of the heat transfer panel support member in the exhaust heat recovery boiler. In this figure, the structure for reducing the temperature of the heat transfer panel support member of the present invention includes a panel support portion 12 and a hollow mount 1.
4, a water supply introduction line 16 and a water supply discharge line 18. The panel supporting portion 12 has a horizontal lower surface 12a which is provided in close contact with the lower surface of each lower pipe holder 5b.
The weight of the heat transfer panels 7, 8 and 9 is supported by a. Further, the hollow pedestal 14 has a horizontal upper surface 14a, and the lower surface 12a of the panel support portion 12 rests on the upper surface 14a to support the entire heat transfer panel via the panel support portion 12. The hollow mount 14 is made of a metal material having a good heat transfer property. With this configuration, the panel support portion 12 and the hollow pedestal 14 constitute a heat transfer panel support member, and when the heat transfer panels 7, 8 and 9 thermally expand and contract, the lower surface 12a of the panel support portion 12 is hollow. The upper surface 14a of 14 can be horizontally slid to prevent the generation of thermal stress.

The water supply introduction line 16 introduces a part of the water supply to the lower header 5b into the hollow mount 14. That is, the upstream end 16a of the water supply introduction line 16
Communicates with the downfall pipe 11a or the water supply inlet line 11b (in the case of the most downstream heat transfer panel 9) that supplies water to the lower header 5b. Further, the water supply and discharge line 18 is configured to flow the water supply inside the hollow pedestal 14 to the lower header 5b.

From the upstream end 16a of the water supply introduction line 16,
The flow path resistance to the lower header 5b via the hollow mount 14 and the water supply discharge line 18 is the upstream end 1 of the water supply introduction line 16.
It is set so that a part (for example, about 1/20 to 1/10) of the water supply that directly flows from 6a to the lower header 5b flows. With this configuration, the relatively low temperature water supply is performed through the water supply introduction line 16 and the water supply discharge line 18 by the self-circulation of the water supply flowing between the heat transfer panels 7, 8 and 9 without providing a high temperature pump or the like. It can be poured into 14.

Further, since the panel support portion 12 of the heat transfer panel 7, 8, 9 is provided in close contact with the lower surface of each lower header 5b, heat transfer from the lower header 5b filled with water is also possible. The panel support 12 can be cooled. That is, since the temperature of the water supplied to the lower pipe is sufficiently lower than that of the exhaust gas (for example, 200 to 300 ° C.), by cooling the hollow mount 14 and the panel support 12 with this water,
The sliding surface located between them, that is, the upper surface 14 of the hollow mount.
a and the lower surface 12a of the panel support part are cooled to a temperature at which high temperature oxidation is unlikely to occur (for example, about 350 to 400 ° C.), thereby eliminating stick slip and diffusion coupling, and the horizontal direction of the heat transfer panel under high temperature and high surface pressure. Can be smoothed out.

The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0020]

As described above, according to the configuration of the present invention,
The frame that supports the heat transfer panel is hollow, and part of the water supply to the lower head is supplied from the water supply introduction line to the inside, so this water supply cools the hollow frame and the top surface and the panel. The lower surface of the support portion can be directly cooled by heat transfer. Further, since the panel support portion of the heat transfer panel is provided in close contact with the lower surface of each lower pipe header, the panel support portion can also be cooled by heat transfer from the lower pipe header filled with water.

Therefore, the structure for reducing the temperature of the heat transfer panel support member of the present invention reduces the temperature of the support member that supports the heat transfer panel, thereby reducing the high temperature oxidation amount of the sliding surface, and the stick slip and diffusion. It has excellent effects such as eliminating the bond and allowing the heat transfer panel to thermally expand smoothly under high temperature and high surface pressure.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an exhaust heat recovery boiler having a heat transfer panel support structure according to the present invention.

FIG. 2 is a panel front view of the exhaust heat recovery boiler of FIG.

FIG. 3 is an enlarged view of part A of FIG.

FIG. 4 is an overall configuration diagram of a conventional exhaust heat recovery combined cycle power plant.

FIG. 5 is an overall configuration diagram of a conventional exhaust heat recovery boiler.

FIG. 6 is a panel front view of a conventional large-sized exhaust heat recovery boiler.

[Explanation of symbols]

 1 Gas Turbine 2 Exhaust Heat Recovery Boiler 3 Steam Turbine 4 Boiler Main Body 4a Frame 4b Partition Plate 5 Heat Transfer Panel 5a Upper Pipe Drawer 5b Bottom Pipe Drawer 5c Vertical Heat Transfer Pipe 6 Panel Support 7,8,9 Heat Transfer Panel 10 Heat Dissipation Recovery boiler 11a Precipitation pipe 11b Water supply inlet line 11c Water supply outlet line 12 Panel support 12a Lower surface 14 Hollow stand 14a Upper surface 16 Water supply introduction line 18 Water supply discharge line

Claims (2)

[Claims] 1. A plurality of heat transfer panels vertically arranged in a boiler main body and arranged at intervals along a horizontally flowing exhaust gas, wherein each heat transfer panel includes upper and lower horizontal pipe headers. A structure for reducing the temperature of a heat transfer panel support member in an exhaust heat recovery boiler, which comprises a plurality of vertical heat transfer tubes connecting the horizontal headers to each other, and is provided horizontally in close contact with the lower surface of each lower header. A panel support part having a lower surface, a hollow pedestal having a horizontal upper surface for supporting the panel support part on the upper surface, a water supply introduction line for introducing a part of the water supply to the lower pipe header into the hollow gantry, and the hollow A structure for reducing the temperature of a heat transfer panel support member, comprising: a water supply discharge line for supplying water from a frame to the lower pipe. 2. The temperature reducing structure for a heat transfer panel support member according to claim 1, wherein an upstream end of the water supply introduction line is in communication with a downfall pipe or a water supply pipe to the lower head. .