Frozen Pipe idea 3

[StoneCold]

This is a problem that most of us in the North face and I wanted to throw this out as an idea and see what anybody had to say about it. We have a frozen waste water line that is headed out to a tanker truck. The line is not insulated or heat traced. We generally keep the line from freezing by blowing it down with air. However that procedure was not followed and now the 1" 150# flanged line is frozen. So what do we do about it.
1. We have tried steaming it by putting steam in the supply line. Anyone who has tried this knows that it is a very slow process tha kind of works if you are lucky.
2. We could put tarps over the line and steam it from the outside but that is hard because it is almost entirely on a pipe bridge.
3. We could hook the welder up to it to thaw the line but that would require waiting until a shutdown period to do that.
4. My maybe not so brilliant plan. What about forcing methanol down the line with a hydraulic hand pump. Lets' assume that we keep the pressure in the line at 230psig or less to keep from bending the flanges. Do you think that you could melt the ice with the methanol. I will try this in a beaker and let you know if it melts the ice in a beaker.

Regards
StoneCold

 

[StoneCold]

Well it did not go so well in the beaker. The temperature drops to about -18C which did melt some of the ice but the "hard" ice did not melt that fast and the mixture ran out of energy before a lot of ice was melted so I think this is probably a bust. If you just had slush it would work fine but the heat capacity of the ice is too high.

 

[Montemayor]

Stone:

I know my method will work - but it depends entirely on your piping layout and geometry.

Do not try to pressurize the pipe with methanol. Instead use a 1/4" plastic tubing to pump neat methanol (preferably warm, if you can heat it)through the tubing as you manually push the tubing through the piping. Allow the methanol to splash out and against any obstacle - probably ice - as the tube works its way down the pipe. The excess methanol will be forced back out through the pipe inlet where you are introducing the methanol, so it's better to rig up a 1" tee with the 90^o outlet pointing down while you push the tubing through the straight run section of the tee, with some rags or stuffing to keep the methanol away from coming straight out at your hands (or gloves).

I know this works because I've seen it done before. But you must not have too many elbows and turns in your piping run. As long as you keep pumping the warm methanol through, it will do its job and the ice will eventually melt. Use as long a roll of plastic tubing as you can find or buy.

Good luck.

 

[zdas04]

You could always use the technique that Idaho uses on their roads--Wait for Summer.

If that isn't practical, then Art's technique looks like your best chance. The key to it working is that most of the stuff coming back is ice crystals that you don't have to melt. I've used the technique with steel tubing (think of an ice pick and solvent jet combined) and got a lot of unmelted ice back, it worked really well.

David

 

[Latexman]

Stonecold,

The probability of success of your method #1 can be greatly increased if it is cycled continuously with steam pressure on, drain line, steam pressure on, drain line, steam pressure on, drain line, and on and on. It helps if you can do this from both ends at the same time. If there are lines next to and close to the frozen line that can be drained and put steam on, that'll help too. Don't use high pressure steam. Depending on your piping layout, add 5 psi to your maximum lift. Be sure the folks that do the cycling can do it from a safe distance. Maybe you can wrap a steam hose along the frozen pipe and let steam blow thru the steam hose?

I use to run a unit that made a chemical that froze at 100 C. Now that, was a pain in the winter!

Good luck,
Latexman

 

[moltenmetal]

Considering what you're going to go through to get the line thawed this time, is there a good reason not to just run a steam tracer or a piece of self-reg electric heat trace along the line and insulate it? That would surely thaw it as well...

 

[Latexman]

moltenmetal is right. Human failure rates are too high to base a critical routine operation on.

Good luck,
Latexman

 

[schnipp]

Do you have a jet blasting company near by? Think of an industrial sized Roto-rooter.

If the pipe is full of elbows or longer than feasible for the previous suggestions, this will work. It will also cost a heck of a lot more, though.

 

[StoneCold]

We got the line going by doing shots of steam in one end and steaming the outside with a hose. Insulating and heat tracing the line is an obvious solution. I was just wondering what creative ideas others had on this problem because it seemed like there has to be a better way to do it.

Thanks
Happy Holidays

StoneCold

 

[hahor]

the fastest way I know is:
- put steam oh the line
- open the first flange connection until the steam comes out, then close it
- and so on with all the other flange connections

this way we got a 200 meter fronzen condensate line back to operation during one night shift

Kind Regards,
hahor

 

[MikeHalloran]

You can use a steam lance (like the methanol but with stainless tube instead of plastic), if you've had the foresight to use crosses instead of tees or elbows.

I spent a horrid winter in upstate NY thawing out frozen process waste and drain lines in a chemical plant. When we had to disassemble the pipe to get it thawed/unclogged, we put it back together with crosses.



Mike Halloran
Pembroke Pines, FL, USA

 

[StoneCold]

MikeHalloran
That is a good suggestion for any other waste lines that I have to build. Maybe too late for this one. Probably just need to bite the bullet and put heat tracing on it.

Thanks

Stonecold

 

[EdStainless]

We have some outdoor waste lines that aren't used often. They have a small diameter SS line that runs full length. It is in the top of the line, held with clips. There are very small holes in it every 5'. This is our steam injection line for use just in case.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[instrument1717]

Low voltage high current injection units will help( or old welding machine ).
For Metal Pipes Use current from welding machine ( without Grounding ) , Connect between flange to flange , the line and the Solid ice will be heated fast .A little current will leak to earth , but the purpose shall be served .
pipe should be isolated from equipments before applying current .( Must Get the help of qualified electricians )
Allow suitable slow heating rate (about 10 deg / 5 minuites).
Cut off Current injection at about 40 deg or even less.
calculate the energy required to lqiuify the volume of ice ,
and the acceptable time for current injection .This information will allow the electricains to size the welding machine and the Injection Current value aproximately.

Do only with qualified Electricians For safety reasons.
Respectfully

 

[instrument1717]

Necessary protections must be at welding machine primary , and start with minimum current.
without protections inadequate operation may damage the machine.