Discussion on the operating temperature conditions for shell-and-tube heat exchangers! Everyone, please participate more!
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According to GB151—1999, the maximum operating temperature for shell and tube heat exchangers is 450 degrees Celsius. However, the materials for shell-and-tube heat exchangers are not fixed. . It’s entirely possible to use high-temperature resistant materials in order to increase the operating temperature Are there strict temperature limits in industry that adhere to this standard? There are two more issues to address: if the temperature difference between the tube sheet and the shell reaches 140 degrees Celsius, but the pulling stress on the tubes remains within acceptable limits, can a fixed-tube-sheet heat exchanger be used? Another question: Can a shell-and-tube heat exchanger be used for flue gas with an inlet temperature of 720–850 and an outlet temperature of 300–250, using molten salt at 170 degrees Celsius as the coolant?
Does GB151 specify a limit of only 450 degrees? It seems like it wasn’t seen. The first question is whether a fixed-tube-sheet heat exchanger can be used; as long as the calculations show it’s feasible, a temperature difference of 140 degrees isn’t too large. The second question seems a bit like a shell-and-tube waste heat boiler.
Reply to 2# Wen Bing: The fourth edition of the \"Chemical Engineering Design Handbook\" mentions that the maximum operating temperature for shell and tube heat exchangers is 450°C. . . But I think there’s a small problem. . .
The temperature of the heat-to-heat exchanger in the sulfur-based acid production conversion system is nearly 550 degrees Celsius, as for the gas-to-gas heat exchange
Design can be carried out in accordance with GB151; the scope of application specified in GB151 does not have any temperature restrictions – temperature is related to the material selection! 450°: 316, CrMo steel, or higher-grade heat-resistant steels are available ； The cold wind pulling force on the tubes and tube sheets should be within the allowable stress range, but an appropriate margin should be reserved ； The stress drops significantly at 450°; just pay attention to the B value. The 140°C temperature difference issue can be resolved with a fixed tube sheet; installing expansion joints should help reduce the pulling force and the stress at the edges of the tube sheet.
I read some material: it seems to be from HTRI; when the temperature difference between the tube side and the shell side is more than 30 degrees, or when the outlet temperatures on these two sides differ by 110 degrees, a floating-head heat exchanger should be used. This is just my personal opinion for reference only.