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will a sloped 8" pipe freeze?

will a sloped 8" pipe freeze?

(OP)
Hello all,

As you can see I'm not a civil, but I've been tasked with designing a drain system for a coal power plant. My issue is, do I need to heat trace the drain line for winter use? Here's some points about the drain:

- 8" diameter carbon or stainless steel pipe; still haven't decided on material
- 20-30 degree slope down a coal conveyor belt enclosure
- About 700 feet long
- Will be a coal dust and water slurry; not sure of the coal dust to water ratio
- Belt enclosure is not heated
- We get down to the single digits or negatives (in Farenheight) for several days at a time, and stay below freezing for weeks in the winter
- Will use the system once a day; approx. 200 gallons over two hours each use

I can't tell if the slurry will build a small layer of ice each use until it clogs and bursts without heat trace, or if it will be ok. Any thoughts are welcome and thank you in advance!

RE: will a sloped 8" pipe freeze?

it will form ice and the rate of ice accumulation will be directly related to the weather and the flow rate, one of which you cannot control. but 200 gallons is not much so it is a risk you need to evaluate

RE: will a sloped 8" pipe freeze?

Unless you're putting boiling water down it it will freeze and block after the first or second day, especially as it is basically dribbling down it. Even boiling water will probably freeze by the end of the third day.

Yes you need to trace it.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

RE: will a sloped 8" pipe freeze?

Waterfalls freeze in weather like that. Your pipe will also freeze unless you trace it.

RE: will a sloped 8" pipe freeze?

Im glad all previous posters gave you the same advice because I agree 100%. But I would also note that the flows you allude to are less than 2 gallons per minute and at that flow I would think that a 2 inch pipe would be more than adequate. Smaller diameter means higher velocity, means less weight of steel, less surface area to lose heat , all of which reduce the liklihood of freezing.

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