Stress caused by the temperature difference between the support and the cylinder wall
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I just read the new version of the standards for container supports, and there was a passage in it. For the flue ducts in the waste heat power generation systems I am working on, the temperature of the cylinder walls is around 400°C. In such cases, the bottom plates and cover plates of the supports are much larger than the rigid rings, which makes this problem even more pronounced. I thought about insulating the supports; insulating the cover plates shouldn’t be difficult. However, the bottom plates are usually connected to the concrete structure or steel framework of the building. If insulation is used to separate the supports from these structural elements, it might cause local areas of the concrete and steel structures to reach higher temperatures, which could have negative effects on those structures. The temperature difference could be quite significant. How can this problem be solved?
Consider adding an insulating layer between the bottom of the ring plate and the civil engineering foundation; this is done for low-temperature equipment, and it’s also necessary for high-temperature equipment.
What materials are used for insulation? Are there any picture albums or diagrams?
According to your description, the rigid ring supports should be insulated together with the flue; the base plates of these supports should be designed to be sliding/rolling in order to allow the rigid ring supports to expand and contract thermally in sync with the flue, thereby **reducing the thermal stress between them**.
Constraints certainly cannot limit thermal expansion. What is described in the screenshot is not limitation of thermal expansion, but rather the stress caused by the temperature difference between the support and the cylinder wall. Insulation is indeed used, but the size of the support base plate is often larger than that of the rigid ring, so a temperature difference is inevitable
The flue should be lined with insulation to reduce the wall temperature; otherwise, what material should be used for a flue at 400°?
As shown in the figure: the flue temperature is 600–700°C; there is an internal lining, and the outer wall temperature is very low, so ordinary saddle supports are sufficient. Take a look at the bottom plate rolling design by the way.
It should be taken into special consideration that we have just conducted a stress analysis on the 500-degree pipeline supports, and it was quite challenging
400 degrees Celsius; according to the current 5121 standard, Q345 is sufficient