High temperature buried piping issues
High temperature buried piping issues
(OP)
Hello,
For a 3 mile long 18" carbon steel buried pipeline within a gas processing plant with a max / min operating temperature of 140 / 0 deg C (32 / 284 deg F), what are the major mechanical / stress issues may be encountered? E.g. overstressing due thermal expansion.
Thanks
For a 3 mile long 18" carbon steel buried pipeline within a gas processing plant with a max / min operating temperature of 140 / 0 deg C (32 / 284 deg F), what are the major mechanical / stress issues may be encountered? E.g. overstressing due thermal expansion.
Thanks





RE: High temperature buried piping issues
Depends on the design code how bad it can be and what you can do about it but the pipe, especially after a long straight section (3-400m) will move in the ground at the bends even if you can't see it. You may need to allow for some movement and accept some strain or have to use special backfill to allow movement without creating a void, but some careful analysis and planning is needed. Get it wrong and it will fail in service or come out of the ground, maybe not immeadiately, but in time, especially if numbe rof cycles is higher than anticipated.
Be very careful about any tee connections or small pipes coming off the main pipe as these often cuase real issues and overstress very easily.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: High temperature buried piping issues
RE: High temperature buried piping issues
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: High temperature buried piping issues
Cheers
RE: High temperature buried piping issues
E=young modulus
a= thermal exp coef
DT= 140 C
v= poisson's ratio
Provided butt welds are used for all connections and large stress raisers are deliverately avoided, you can use the design fatigue curves with the known number of cycles and determine the max allowed inherent stress raiser permitted for desing life of the UG system.
Also, as I have seen undulating shell expansion joints used in some types of heat exchanger shells ( 18"), the same undulation style expansion joint can be installed on either side of each of the concrete anchors.
"Nobody expects the Spanish Inquisition! "
RE: High temperature buried piping issues
Independent events are seldomly independent.
RE: High temperature buried piping issues
RE: High temperature buried piping issues
Cheers
RE: High temperature buried piping issues
Independent events are seldomly independent.
RE: High temperature buried piping issues
Cheers
RE: High temperature buried piping issues
3rd reference on page,
http://solutions.3m.com/wps/portal/3M/en_US/Corros...
Thanks again.
Independent events are seldomly independent.
RE: High temperature buried piping issues
If it goes in at 130 deg, it won't come out at 130 deg C. Or, it will, but will have a lot of condensate. 8<)
Even well insulated in air that would lose a lot of energy, but underground with the insulting can in direct contact to soil/water/rock?
RE: High temperature buried piping issues
Independent events are seldomly independent.
RE: High temperature buried piping issues
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: High temperature buried piping issues
The pipe will be installed at ambient temp 30 C,and may heat up to 130C, inducing a compressive load due to thermal stress. As long as the pipe is provided sufficient "wiggle room", the pipe will horizontally deflect due to compressible collumn collapse, and will relieve the compressible stress in that manner. The same result occurs in boiler loose piping and other cases with long unsupported pipes undergoing cormpessible thermal stresses.
"Nobody expects the Spanish Inquisition! "
RE: High temperature buried piping issues
https://www.logstor.com/Brochures/HT%20Pipes/HT%20...
Best regards, Morten
RE: High temperature buried piping issues
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way