JPH0914576A - Heat insulating structure for duct inside of high temperature fluid - Google Patents

Abstract

PURPOSE: To prevent an outer casing from generating a high temperature, by providing a flat plate-shaped shelf having a part not in contact with an internal surface of a casing to be mounted and secured to a bolt, and providing a heat insulating layer by a heat insulating plate material provided between an internal surface/wall of the outer casing. CONSTITUTION: A structure is formed such that a bolt 23 is welded to an outer casing 21 to place a flat plate-shaped shelf 24 on the bolt 23. A length of the shelf 24 is formed not to the length of the innermost layer of internal heat insulation but to the length of an inner layer of this heat insulation. The innermost layer is formed in a structure supported by the bolt 23, and for the bolt 23, by lapping joints of the heat insulating layer, that is, joints of heat insulating plate materials 27, 28, also heat convection can be prevented. In the bolt 23, since a sectional area conducting heat is small as compared with the shelf 24, internal heat is difficult to be transmitted to the outer casing 21, accordingly to avoid generation of a high temperature of the outer casing 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal heat retaining structure for a high temperature fluid duct.

[0002]

2. Description of the Related Art In recent years, a combined cycle in which a Brayton cycle and a Rankine cycle are combined, and repowering in which a gas turbine is combined with an existing boiler to increase the output have become more and more popular. FIG. 2 is an overall configuration diagram of an exhaust heat recovery type combined cycle power plant which is one of combined cycles. In FIG. 2, 1 is an air compressor,
2 is a combustor, 3 is a gas turbine, 4 is a heat exchanger, 5 is a steam turbine, 6 is a generator, 7 is a condenser, and 8 is a pump.

That is, the exhaust of the gas turbine 3 is a heat exchanger 4 (HRSG: Heat Recovery) which is an exhaust heat recovery boiler.
The steam turbine 5 is driven to recover the heat and generate steam to drive the steam turbine 5.
Such a combined cycle takes advantage of the advantage that the maximum utilization temperature of the gas turbine is high and the advantage that the minimum utilization temperature of the steam turbine is low, high thermal efficiency and partial load efficiency, short start-stop time, It has advantages such as a small amount of hot drainage. The exhaust heat recovery boiler shown in this figure is also applied to repowering to recover the exhaust heat of the gas turbine.

FIG. 3 is an enlarged sectional view showing a part of the lining of the heat exchanger 4 of FIG. In FIG. 3, 9 is an outer casing, 10 is an inner wall provided in parallel with the casing 9, 11 is a flat shelf welded to the casing 9, and 12, 13 and 14 are inner surfaces of the casing 9. A heat insulating plate material that forms a heat insulating layer between the inner walls 10, and 15 are bolts whose base is fixed to the heat insulating plate material 14 and whose head is fastened to the inner wall 10.

That is, as shown in FIG. 2, the high temperature exhaust gas from the gas turbine 3 flows into the heat exchanger 4,
Generally, the temperature of the exhaust gas is 650 to 690 ° C., and in FIG. 3, the high-temperature exhaust gas flows at right angles to the paper surface, but the heat insulating layers 12, 13 and 14 are used to prevent heat inside thereof from being transferred to the outer casing 9. Is provided.

[0006]

As described with reference to FIG. 3, in the prior art, since the shelf 11 is a flat plate and is directly welded to the outer casing 9, the heat conduction from the high temperature fluid inside the shelf 11 is prevented. There is a problem that the outer casing 9 tends to be high in temperature, and the outermost heat insulating plate 12 to the intermediate heat insulating plate 13 and the innermost heat insulating plate 14 are large.
Since the heat-retaining seam has a horizontal straight line, there is a problem in that heat convection occurs in the gap, which causes the outer casing 9 to become hot.

[0007] The present invention is to solve the above problems. That is, an object of the present invention is to provide an internal heat retaining structure for a high temperature fluid duct in which the outer casing is prevented from reaching a high temperature.

[0008]

In order to achieve the above object, the present invention provides an outer casing, an inner wall arranged in parallel with the casing, and a bolt welded to the casing and fastened to the inner wall. A flat-plate shelf that has a portion that does not come into contact with the inner surface of the casing and is fixedly mounted on the bolt, and a heat insulating layer formed by a heat insulating plate material provided between the inner surface of the outer casing and the inner wall. I had it.

[0009]

According to the present invention, the outer casing, the inner wall provided in parallel with the casing, the bolt welded to the casing and fastened to the inner wall, and the portion not contacting the inner surface of the casing are provided. Since it has a flat plate-shaped shelf that is mounted and fixed to the bolt and a heat insulating layer made of a heat insulating plate material provided between the inner surface of the outer casing and the inner wall, the shelf has a flat plate shape. However, since it is not directly in contact with the outer casing but is fixedly mounted on a bolt welded to the outer casing, the bolt has a very small cross-sectional area through which heat passes as compared with the shelf. It is difficult for the internal heat to be transferred to the outer casing, so that the temperature of the outer casing is prevented from increasing.

[0010]

1 is an enlarged sectional view of an embodiment of the present invention shown in correspondence with FIG. In FIG. 1, 21 is an outer casing, 22 is an inner wall provided in parallel with the casing 21, and 23 is an inner wall 22 welded to the casing 21.
Bolts 24 fastened to the outer casing 21 have a portion (a distance L apart) that does not come into contact with the inner surface of the outer casing 21, and are fixed to the bolts 23 by being welded and fixed to the bolts 23. Reference numerals 26, 27 and 28 denote heat insulating plate members forming a heat retaining layer between the outer casing 21 and the inner wall 22.

Here, the loads of the heat insulating plates 25 and 26 are supported by the bolts 23 via the shelf 24, and the loads of the upper heat insulating plate 27 and the lower heat insulating plate 28 of the innermost layer are directly supported by the bolts 23. There is.

That is, a bolt 23 is welded to the outer casing 21, and a flat shelf 24 is placed on the bolt 23. The length of the shelf 24 is not increased to the innermost layer of the internal heat insulation but to the innermost layer thereof. The innermost layer has a structure in which it is supported by bolts 23. Because of the bolts 23, thermal convection can also be prevented by wrapping the joints of the heat insulating layer, that is, the joints of the heat insulating plate members 27 and 28.

In the internal heat retaining structure of the high temperature fluid duct constructed as shown in FIG. 1, even if the shelf 24 is flat, it does not directly contact the outer casing 21,
Since it is mounted and fixed to the bolt 23 welded to the outer casing 21, the bolt 23 has a very small cross-sectional area through which heat passes as compared with the shelf 24.
It is difficult for the internal heat to be transferred to the outer casing 21, so that the temperature of the outer casing 21 is prevented from increasing.

[0014]

As described above, according to the present invention,
An outer casing, an inner wall provided in parallel with the casing, a bolt welded to the casing and fastened to the inner wall, and a portion that does not contact the inner surface of the casing and is fixedly mounted on the bolt. Since it is provided with a flat plate-shaped shelf and a heat insulating layer made of a heat insulating plate provided between the inner surface of the outer casing and the inner wall, the shelf does not directly contact the outer casing and is welded to the outer casing. Since the bolt is mounted and fixed on the bolt, the cross-sectional area of heat passing through the bolt is very small as compared with the shelf. Of high temperature is prevented. Therefore, according to the present invention, a structure that is stable over time is provided, and it is not necessary to keep the internal heat and rework the external casing, and it is possible to use the device for a long period of time.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing an embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a conventional exhaust heat recovery combined cycle power plant.

3 is an enlarged cross-sectional view of the heat exchanger of FIG.

[Explanation of symbols]

 21 Outer casing 22 Inner wall 23 Bolt 24 Shelf 25 Insulating plate material 26 Insulating plate material 27 Insulating plate material on the uppermost inner layer 28 Insulating plate material on the uppermost inner layer

Claims (2)

[Claims] 1. An outer casing, an inner wall provided in parallel with the casing, a bolt welded to the casing and fastened to the inner wall, and a portion that does not contact the inner surface of the casing. An internal heat retention of a high temperature fluid duct, comprising: a flat plate-like shelf fixedly mounted on a bolt; and a heat insulation layer formed by a heat insulating plate material provided between an inner surface of the outer casing and the inner wall. Construction. 2. A bolt in which an upper heat insulating plate material and a lower heat insulating plate material of the innermost layer of the heat insulating layer are lapped and joined, and loads of upper and lower heat insulating plate materials of the portion are fastened to the inner wall. The internal heat retaining structure of the high temperature fluid duct according to claim 1, which is supported by.