high temperature pipe-in-a-pipe systems
high temperature pipe-in-a-pipe systems
(OP)
I am looking people (someone, anyone) who have experience with high temperature pipe-in-a-pipe systems. I was told of a facility that uses a such a system for hot air at 1350+ F and 650 psig. The inside pipe (12") is vented to the outside pipe (~20") such that it is not pressure retaining; it acts as a conduit for the flow only. The outer pipe is insulated from the inner pipe and is pressurized to 650 psig; However, since no flow exists between the inside and outside pipe, there is very little heat transfer such that normal piping materials can be used The inner vented pipe has expansion joints to allow thermal growth independent of the outside pipe. Is anyone aware of a manufacturer of such a system?





RE: high temperature pipe-in-a-pipe systems
RE: high temperature pipe-in-a-pipe systems
RE: high temperature pipe-in-a-pipe systems
I can see some issues with that design including what insulation is used that is good at that temperature, how do you deal with any bends or tees in the inner pipe and whilst the gas flow will be very low between the inner and outer pipe, there will be some and how do you deal with those hot spots? A lot will be on how many holes there are and how do you stop travel of gas due to pressure difference.
That looks quite a difficult combination ( 730C and 45 barg) so imagine it would have come up with a pretty unique solution.
I've seen cryogenic pipe in pipe systems using low expansion inner pipe and that is quite hard.
What sort of temperatures and pressures are you looking at or is the 1350F/650 psi, your requirement?
Foamglas insulation goes to 650C and it's usually much easier to deal with expansion in one pipe rather than differential. There other external insulations as well.
Remember - More details = better answers
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RE: high temperature pipe-in-a-pipe systems
I appreciate your comments.
A system like this exists in Germany but I am having a hard time time finding any information concerning the manufacturer or details concerning the design. 1350 deg F at 650 psig is an the actual operating condition.
RE: high temperature pipe-in-a-pipe systems
The differential expansion issues in a pipe in pipe system are a bitch to deal with and expansion joints / bellows etc have a poor track record, especially in terms of fatigue and corrosion
I meant what is your application - identical to the previous one??
what service is this? I've seen hot flue gases before, but not at 650 psi.
No, you need something like space shuttle linings I think and a fairly constant operation. Anything which starts and stops is a difficult scenario to deal with reliably.
If you go for a single pipe with internal thermal protection, you'll probably end up with an outer protective pipe to catch the situation if it fails. Escape of that sort of gas at that sort of pressure will lead to catastrophic failure and possible deaths very quickly if you don't.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: high temperature pipe-in-a-pipe systems