Material selection for cracking reactors containing a small amount of hydrogen fluoride gas
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As the title suggests, material selection for reaction vessels. At a temperature of 200°C, very little hydrogen fluoride and BF3 is produced during pyrolysis. I was wondering if anyone has any recommendations for materials to use in this context; thank you!
If the volume of the reactor is not large, copper or Monel alloy can be used. If the reactor volume is very large, only materials lined with PTFE or coated with PTFE can be used. Temperature is not an issue, but it is necessary to ensure that the coating remains intact.
The reactor has a capacity of 5000L. What type of coating are you referring to, and what is its heat transfer efficiency? The jacket should be heated with heat transfer oil.
Hydrogen fluoride corrodes almost all stainless steels and ferroalloys, so many of them cannot be used; moreover, at such high temperatures, there is only one material whose suitability is still uncertain, @qugd – namely 904L stainless steel, a type of stainless steel containing 1.5% copper. The best option that can be used is a PTFE lining, but strict electrical spark leak testing must be carried out.
But the PTFE lining doesn’t provide good heat transfer; we use it for pyrolysis. It needs to be kept heating continuously.
What do you think of the heat conductivity of non-stick pans? The PTFE material used for coating that layer, I think it’s fine. A container with a capacity of 5 liters is already quite large.
Can a non-stick pan coated with PTFE withstand such high temperatures?
It can be used; for long-term use, a temperature of around 250 degrees is sufficient. We have used smoke gas pipelines with a transition section lined with PTFE, and they perform well at operating temperatures of 260–280°C.
Only tetrafluoro materials can withstand temperatures around 100 degrees; at 200 degrees, even tetrafluoro materials will deform