Steam heat transfer question
Steam heat transfer question
(OP)
Been working out a problem I have to figure out at work. I have a large pipe (~6") that needs to be steam heat traced but i dont know much about the fluid properties within the pipe. This fluid will be heateded in a separate tank and pumped across a plant site. the steam heat trace just needs to maintain temperature. Is it ok to assume - if I keep the inner pipe temperature the same as I need the fluid temp (mid 100 F) i can use that temperature to figure out how much steam i need to supply?





RE: Steam heat transfer question
You are really only making up for external heat loss.
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P.E. Metallurgy, Plymouth Tube
RE: Steam heat transfer question
RE: Steam heat transfer question
While it is more expensive to install it can be designed to hold temp over very long runs.
It also does not waste steam, and in many plants the O&M cost is less for electric than steam tracing.
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P.E. Metallurgy, Plymouth Tube
RE: Steam heat transfer question
RE: Steam heat transfer question
Look into electric.
Steam systems tend to waste a lot of steam and can require a lot of maintenance.
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P.E. Metallurgy, Plymouth Tube
RE: Steam heat transfer question
Ill try to convince them but the client wants steam due to having it already on site, and probably some other things. Electric makes much more sense to me, and it is what I have done at previous jobs.
i believe its only going roughly 500ft, but this is still proving to be a challenge. a couple calculations ive used have it a bit all over the place - ranging around 30 btu/hr/ft (most including my calc sheet i made give me this - even electric trace design programs) lost up to around 100.
im assuming 10 degrees F out with a moderate wind. I also mistakenly said 6" pipe when i meant to write 3" with 4" foam glass insulation and a metal jacket.
RE: Steam heat transfer question
Electric makes much more sense: The new electric bands go inside the new pipe's insulation. No other new pipe supports, new pipe support structural steel and foundations, no new cuts and taps into existing steam lines ......
RE: Steam heat transfer question
RE: Steam heat transfer question
RE: Steam heat transfer question
I ended up making a sheet that covers all the radiation, conduction, and convections (Free and forced) heat losses per foot.
what i get from that, Ill just divide by 1000 to get the lbs/hr i need.
RE: Steam heat transfer question
RE: Steam heat transfer question
If the process is using steam, they most likely have a high pressure condensate recovery, with hot condensate being either re-fed directly into the boiler or heat exchanged before arrival to the hot well.
How about using that hot condensate in a closed loop with the HP condensate recovery tank to trace the pipe?
That might result in very cheap energy (specially if their condensate recovery system is not very efficient) and at the end its just pumping condensate.
It could be done counterflow with HP condensate tracing flow rate linked to end fluid target temperature.
BR,
Rto