How to prevent freezing in PTFE-lined pipes
Thread Content
Material: 0.5% dilute sulfuric acid. The pipe material is A105 with a PTFE lining. The design temperature for low-pressure steam is 189 degrees. Is it possible to use 1/2” low-pressure steam pipes for trace heating? There’s no hot water available on site. My main concern is that the PTFE lining might get damaged; the maximum operating temperature for PTFE is below 160 degrees. Does anyone have experience in this area? How should one handle trace heating pipes or deal with such situations?
Electric heating can be used, with an adjustable temperature setting range.
There should be no problem; using steam for heating should work fine.
What is the lowest temperature during winter where you are? Heating for steel-lined PTFE pipes is unnecessary if there is concern that the PTFE will be damaged. Polytetrafluoroethylene basically does not suffer from cold-induced damage; its main concerns are tearing and deformation caused by vacuum. There’s one more thing I don’t understand: the steam needs to be lined with PTFE. Since it is lined with PTFE, it is used in environments with acids and alkalis; for pipes exposed to such substances, the condensation temperature is very low.
At high temperatures over an extended period, tetrafluoride might not be able to withstand it either, right?
Fluorine-lined valves are suitable for temperatures up to 160°C, while fluorine-lined fittings are suitable for temperatures up to 180°C. In the situation described by LZ, it is better to use metal fittings; although their price is higher, their longer service life makes them a worthwhile choice
Because we have already reached this point in the construction work, the client requested that PTFE pipes be used for heat circulation. The lowest temperature in winter here is -15 degrees Celsius. Since the cost of using electric heating is high, the client wants to save money. The decision now is to insert insulating material between the pipe used for heat circulation and the pipe that needs to be heated. Additionally, during winter, the opening degree of the heat circulation valve will be reduced. This is what we decided on site, and it will also be implemented accordingly.
This way, there’s no problem at all. Due to heat transfer and heat dissipation, although the temperature of the heating steam is 180 degrees, the temperature of the PTFE-lined tube does not reach this value; it is even much lower than that. It would be better to add an insulating layer