JPS5932714B2 - high temperature piping - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in high-temperature piping through which high-temperature, high-pressure fluid flows.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a structure that reduces thermal stress in a seal plate that prevents short baths of fluid penetrating into the insulation.

The usefulness of so-called high-temperature piping is attracting attention as a pipe through which extremely high-temperature, high-pressure fluid with a temperature and pressure of about 1000° C. and 40° C./CTit flows through.

High-temperature piping consists of an inner wall pipe as a heat-resistant boundary, a heat insulating material coated on its outer periphery, and a pressure pipe (outer pipe) located at the outermost periphery as a pressure-resistant boundary that maintains the system pressure.
It consists of To date, various inventions and inventions related to high temperature piping have been made.
An idea has been made.

However, the biggest problem currently facing detection is the technology for preventing short buses. The structural types of high-temperature piping are broadly divided into single-flow piping, in which high-temperature fluid flows through the center, and double-flow piping, in which two high-temperature fluids flow through the center and at the same time in an isolated manner on the outer diameter. .

For example, in double piping, a high-temperature fluid (for example, 1000°C, 40 Kf/dg He gas) flows inside the inner wall pipe in the center,
The annular flow path between the outer tube and the middle tube is filled with a cryogenic fluid (e.g. 400
℃, 4lKf7/(He gas of V7f9) flows.

The barrier separating these two fluids is composed of an inner wall tube, a heat insulating material, and an intermediate tube. Therefore, the outer tube (pressure tube) and the intermediate tube are forcibly collared with low-temperature fluid, and no difference in elongation occurs due to thermal expansion. However, a large relative elongation difference occurs between the intermediate tube and the inner wall tube. The above-described problem of relative elongation difference also occurs between the outer pipe (pressure pipe) and the inner wall pipe in the case of single-flow piping.

Therefore, at the joints of inner wall pipes in high-temperature piping,
A slide joint is used to absorb thermal expansion. However, the high-temperature fluid flowing through the inner wall tube causes a pressure loss of a greater or lesser extent on its way from one slide joint to the next, and this causes a short pass. If the above-mentioned short pass occurs, the effectiveness of the insulation material will be significantly reduced, and the intermediate pipe (
Hot spots are formed in the pressure pipe (in the case of double piping) or pressure pipe (in the case of single flow pipe), and the strength of the pipe is extremely reduced, causing breakage.

At the same time, various problems such as increased heat loss of the fluid occur. In order to prevent such short passes in high-temperature piping, the only way is to install a seal plate that completely partitions the inner wall pipe and the intermediate pipe or pressure pipe in the radial direction.

However, when installing seal plates, the issue of thermal stress cannot be ignored. The temperature of the fluid flowing inside the inner wall tube is 1,
000'C, the temperature of the inner wall tube itself is about 1,00'C.
It is heated to 0℃.

On the other hand, the intermediate or pressure pipe is designed to maintain its temperature at 400'C to ensure safety in use, and a heat insulating material is used to form the temperature barrier. If a 1,000° C. inner wall tube and a 400° C. pressure tube are simply joined together by a radial seal plate, a large temperature drop of 600° C. will occur in the seal plate.

For this reason, the seal plate is subject to circumferential shear stress (
It is immediately destroyed by thermal stress). In order to alleviate the thermal stress of the seal plate, the distance between the high temperature part (inner wall pipe) and the low temperature part (intermediate pipe or pressure pipe) is increased to make the thermal gradient gentler, thereby avoiding failure due to thermal stress. It is possible that

However, if this method were to be implemented, the length of the seal plate required to alleviate the temperature drop of approximately 60°C would be enormous. For this reason, the sea 7"/plate has to be installed at a very close to horizontal angle, such as 4 walls or 5 walls, with respect to the pipe axis between the narrow inner wall pipe and the intermediate pipe or pressure pipe. No. In that case, the technical difficulty in manufacturing the pipe becomes significant, and filling with insulation material becomes difficult.The present invention
As a result of various recent studies on thermal stress relaxation methods, it has been found that the heat in the part of the seal plate near the high temperature part (the first part where heat flows from the high temperature part metal to the seal plate as a heat flow, hereinafter referred to as the transition part) The damage caused by stress is the greatest, and by alleviating the thermal stress in the transition area,
This research focuses on the research results that show that the seal plate can be used safely and does not lead to destruction.

That is, in the present invention, the so-called transition part, which is the vicinity of the joint between the seal plate and the inner wall pipe, is formed as a parallel part that is parallel to the inner wall pipe by an appropriate length, and the parallel part is parallel to the inner wall pipe in the longitudinal direction. Another feature is that the temperature in both the wall thickness direction is maintained at approximately the same temperature as the inner wall tube. In other words, in the parallel portion, almost no temperature gradient occurs in either the longitudinal direction or the thickness direction, and thermal stress is also slightly suppressed or relaxed. In the seal plate, a thermal gradient is gradually generated from a portion past the parallel portion to form a thermal drop difference between a high temperature portion and a low temperature portion.

However, the thermal gradient that occurs in areas other than the parallel portion can be considered to be almost one-dimensional and uniform in the longitudinal direction of the seal plate, and the damage caused by thermal stress is no longer so large that it does not impede safety in use. This has been experimentally confirmed. Next, the present invention will be explained with reference to illustrated embodiments.

FIG. 1 shows a double piping system embodying the invention. In the figure, 1 is an inner wall pipe, 2 is a heat insulator, 3 is an intermediate pipe, and 4 is an inner wall pipe 1
It refers to the slide joint part of. Further, numeral 5 in the figure is a seal plate. Furthermore, 6 in the figure is an outer tube (pressure tube) that forms a flow path 7 on the outside of the intermediate tube 3. The high-temperature, high-pressure fluid flows in the inner wall tube 1 as shown by arrow A.

Then, the returning fluid whose temperature has been lowered to about 400°C by the heat exchanger section (not shown) on the right side of FIG.
It flows through the flow path 7 as shown by arrow B. As is clear from FIG. 2, the seal plate 5 is an integral extension of the inner wall tube 1, and its tip abuts against the intermediate tube 3, and is welded watertightly at the position 8.

In the inner wall tube 1, the seal plate 5 is attached to one end Y forming the slide joint 4.
A parallel portion 5a having an inner diameter close to the outer diameter surface of ``
and the slide joint 4 within the range of the parallel portion 5a.
is formed.

The end portion v has a ceramic 9 in a portion inscribed in the parallel portion 5a to prevent high-temperature adhesion (FIG. 4). Seal plate 5
As is clear from FIG. 2, the joint 10 with the inner wall tube 1
Following this, there is an inclined part 5b as a process leading to the parallel part 5a.

Following the parallel portion 5a, there is an inclined portion 5c having an angle that does not hinder the filling of the heat insulating material, and then there is a parallel portion 5d for providing a distance necessary for alleviating the thermal gradient. When reaching the part to be joined to the intermediate pipe 3, it has a sloped part 5e with an angle that does not hinder the filling of the heat insulating material, and the tip thereof is welded to the intermediate pipe 3. The heat insulating material 2 used in this double piping is a refractory heat-resistant fiber such as Kao Wool (trade name).

However, since the fibrous heat insulating material is easily influenced by the flow of fluid, a metal foil laminated heat insulating material 2' is used in the fluid flow portion near the slide joint 4. Further, the portion where the face metal 11, which prevents the fireproof insulation fibers from being washed away, is inscribed in the intermediate tube 3 is slidable. FIG. 5 shows an embodiment of single-flow piping. This is due to the structure of the double piping described above.
is removed, and the intermediate pipe 3 is replaced with a pressure pipe 3'', but the other configurations remain the same. It comes into direct or indirect contact with the fluid flowing inside the pipe 1.

Therefore, the portions from the inner wall tube 1 to the parallel portion 5a are heated to approximately the same temperature as the fluid, and almost no thermal stress is generated in these portions. The risk of thermal stress in these parts is therefore avoided and the object of the invention is well achieved. Inclined portion 5C1 following parallel portion 5a Parallel portion 5
d. Although a considerable thermal gradient occurs in the inclined portion 5e, it is one-dimensional in the tube axis direction and elongation is allowed (one end of the inner wall tube is not restrained as a slide joint), so there is no stress risk. There is no such thing.

As described above, according to the present invention, although the improvement is extremely simple by simply providing the parallel portion 5a on the seal plate, the risk of thermal stress on the seal plate itself and the intermediate pipe or pressure pipe is eliminated. , we can provide highly safe high-temperature piping. At the same time, the axial length of the seal plate can be reduced and its installation angle can be increased, making it easy to construct high-temperature piping and providing advantages in manufacturing, such as making it easier to fill with insulation material. This also contributes to reducing the cost of high-temperature piping.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a double piping embodying the present invention, Figures 2-
FIG. 4 is an enlarged detailed sectional view of the section of FIG. 1. Further, FIG. 5 is a sectional view of a single flow pipe in which the present invention is implemented.
1...Inner wall pipe, 2, 2'...Insulating material,
3...Intermediate pipe, 3'...Pressure pipe, 4.
...Slide joint, 5 ... Seal plate, 5a ... Parallel part, 6 ... Outer tube, 7 ... Channel.

Claims (1)

[Scope of Claims] 1. In high-temperature piping consisting of an inner wall pipe through which high-temperature fluid flows, a heat insulating material coated on the outer periphery of the inner wall pipe, and a pressure pipe located on the outer periphery of the heat insulating material, there is a gap between the inner wall pipe and the pressure pipe. 1. A high-temperature piping characterized in that a part of a seal plate that partitions the pipe in the radial direction near the joint with the inner wall pipe is formed into a parallel part that is close to and parallel to the inner wall pipe. 2. An inner wall pipe through which high-temperature fluid flows, a heat insulating material covering the outer periphery of the inner wall pipe, an intermediate pipe located on the outer periphery of the heat insulating material, and an appropriate gap provided between the outer periphery of the intermediate pipe to form a flow path. In high-temperature piping consisting of the outermost pressure pipe arranged, the vicinity of the joint with the inner wall pipe in the seal plate that partitions between the inner wall pipe and the intermediate pipe is formed into a parallel part close to and parallel to the inner wall pipe. High-temperature piping characterized by consisting of: