JPS5912955B2 - ultra high temperature heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultra-high temperature heat exchanger that operates in a high temperature range of around 1000°C.

Furthermore, we are pushing the limits of permissible physical and mechanical properties of structural materials used in ultra-high-temperature regions, and are developing multilayer structures with improved structures that utilize the unique properties of each material to the maximum extent possible. This invention relates to a high-temperature heat exchanger with a shell structure. With the progress and practical application of nuclear energy utilization technology, the structural type and performance of the various heat exchangers used therein have also changed from conventional ones to new ones.

Great progress has been made in increasing the capacity and temperature of heat exchangers. Recently, it is not uncommon to see heat exchangers operated in the so-called ultra-high temperature and high pressure region with a pressure of several I0 to 9/Ctli and a temperature of about 1000°C. As for the structural type, tubular heat exchangers are the most popular. Increasing the capacity and increasing the temperature of heat exchangers is a natural outcome to meet the demands of technological innovation and at the same time obtain economic benefits.

However, the issue of high temperatures raises many difficult questions regarding the primary structural metal materials used in heat exchangers. One of them is the limit of material strength and the problem of practicality. Furthermore, problems of thermal expansion and thermal stress occurring in the components cannot be avoided. We will leave the discussion and strategies for technical solutions regarding thermal expansion and thermal stress to another occasion.

In the present invention, we sought a technical solution to the limitations of high temperature strength and its practicality in the main structural materials used in heat exchangers. The high-temperature strength of the material referred to here can be divided into heat-resistant strength and pressure-resistant strength (yield strength). It is well known that VN metal materials have physical properties depending on the operating temperature.
Mechanical properties vary significantly.

The higher the temperature, the lower the strength. Therefore, 1000
Strict safety measures against high-temperature strength are required for the structural materials of ultra-high-temperature heat exchangers that operate in the ultra-high temperature range around ℃. Even if a special high-alloy material has performance superior to ordinary eye fever materials, it becomes difficult to expect the required pressure resistance as the operating temperature increases. In this way, practical safety design was almost impossible due to problems with high-temperature strength, and even if it were possible, the thickness of the parts would be extremely large, causing problems with thermal stress and economical obstacles. I end up standing in my way. Therefore, the main object of the present invention is to improve the high-temperature strength of a structural part on which pressure load and heat load act simultaneously and must withstand both, specifically, the body structure of a tubular heat exchanger. To solve the above problem. In other words, the structure of the shell is multilayered, consisting of a heat-resistant material that bears the heat load, a pressure-resistant material that bears the pressure load, and an insulating material that reduces heat conduction from the heat-resistant material to the pressure-resistant material as much as possible. Another object of the present invention is to provide a tubular heat exchanger having a multilayer structure. According to the present invention, the heat-resistant shell is provided on the innermost periphery of the heat exchanger shell, which is made of a material that does not have a very high pressure resistance but has very high heat resistance strength. A heat insulating material is provided on the outer surface of this heat-resistant rigid. And although the heat resistance strength is not so great at the outermost periphery,
A pressure cylinder made of a material with very high pressure resistance is provided. Thus, the barrel according to the invention has at least three layers. In order to make the pressure-resistant cylinder have a pressure-resistant function, the heat-resistant cylinder is provided with an internal flow. A fluid leak is provided that allows a portion of the body to fill the pressure shell to achieve static matching of fluid pressure.

In addition, in order to expect a heat insulating effect when the pressure cylinder is filled with fluid, the fluid filled in the pressure cylinder is configured to completely stagnate and not flow. In addition to this double-tube heat exchanger, it is also possible to omit the use of a heat-resistant shell and a heat insulating material in places where the heat load on the shell is reduced.

Next, the present invention will be explained with reference to embodiments shown in the drawings.

FIG. 1 shows an example of a U-shaped tubular heat exchanger according to the present invention.

That is, a large number of heat transfer tubes 2●● bent in a similar shape to the shell are arranged in a U-shaped shell 1, and both ends of the tubes are fixed to the shell with tube plates 3 and 4. Supported. Thermal expansion of the heat exchanger tube 2 is advantageously absorbed and alleviated at the U-bend portion 5. The high-temperature primary fluid enters the cylinder from the inlet nozzle 6 as shown by arrow A at a temperature of approximately 1000°C, and as a result of heat exchange, the temperature drops to a medium-low temperature and exits from the outlet nozzle 7 as shown by arrow B. I'm going to go. On the other hand, the low-temperature secondary fluid enters from the inlet nozzle 8 as shown by arrow C, and while flowing through the heat exchanger tube group 2..., its temperature is raised by heat absorption due to heat exchange, and the temperature rises by about 1000 m It leaves at a temperature of around ℃. According to the present invention, in the above-described structure and heat exchanger, the shell 1 has a heat-resistant shell 10 on the innermost periphery, a heat insulating material 11 lined on the outside thereof, and a pressure-resistant shell 12 on the outermost periphery. It has a multilayer structure consisting of three layers.

The heat-resistant shell 10 is made of a very thin heat-resistant material that can withstand use at extremely high temperatures, such as Hastelloy IX,
Only the heat load is borne.

The heat insulating material 11 is one for high temperatures.

In addition, the Taigodou 12 is designed and manufactured using stainless steel or the like which has a moderately high heat resistance strength and can sufficiently withstand fluid pressure. In addition, the space between the heat-resistant shell 10 and the pressure-resistant shell 12 is separated by a partition plate 1.
It is divided into three airtight, independent rooms.

At least one communication hole 14 is provided for each chamber, and even if a part of the fluid in the pressure shell flows into the pressure shell, it remains there, thereby preventing the temperature of the pressure shell from rising. Therefore, the heat load of the fluid in the shell is mainly borne by the heat-resistant shell 10, and only heat at a temperature that does not interfere with strength acts on the pressure-resistant shell 12 due to the action of the heat insulating material 11.

On the other hand, with the static adjustment of the fluid pressure throughout the cylinder, the heat-resistant cylinder 10 is simply immersed in the internal fluid, and the entire pressure load is borne by the pressure-resistant cylinder 12. Ru. Next, FIG. 2 shows a double tube heat exchanger →U according to the present invention.

In the well-known double tube type heat exchanger, the flow of fluid in the body is unified by the guide pipe, which greatly contributes to improving the heat transfer coefficient and, by extension, the thermal efficiency.

15 in FIG. 2 is a guide pipe.

Both tube ends are supported by upper and lower tube plates 16 and 17 fixed to the shell. In the case of this double tube type, tube plates 16 and 17
The primary fluid is also stored between the two, but this is for the purpose of statically balancing the fluid pressure, and the temperature of the retained fluid is not so high.

After all, the high temperature area is the inlet side of the primary fluid 4
and 17 surrounded by tube sheets, and a portion below tube sheet 4 corresponding to the outlet side of the secondary fluid. In the second example, the shell is constructed as a triple structure consisting of a heat-resistant shell 10, a heat insulating material 11, and a pressure-resistant shell 12, but in some cases, only the high-temperature section may be constructed with a multilayer structure similar to the above. It can also be configured in the body to achieve the desired purpose.

According to the above, according to the present invention, regarding the structure of the body of a heat exchanger where high temperature strength is an issue, the functions of the members bearing the pressure load, the members bearing the heat load, and the structural materials can be separated. Because we independently select materials and design strength for each functional element, we can safely and economically increase the capacity and temperature of heat exchangers.

[Brief explanation of drawings]

1 and 2 are sectional views showing different embodiments of the heat exchanger according to the invention.

Claims (1)

[Claims] 1 The body of the tubular heat exchanger is formed of a heat-resistant shell on the innermost periphery, a heat insulating material lined on the outside, and a pressure-resistant shell on the outermost periphery, and the outer periphery of the heat-resistant shell and the inner periphery of the pressure-resistant shell are The annular gap between the two is divided by a partition plate, a communication hole is provided in the heat-resistant shell to allow internal fluid to flow into the partition, and a large number of heat transfer tubes are supported on a tube plate provided in the middle of the heat-resistant shell. Ultra high temperature heat exchanger.