Hydrostatic alternative of methanol 1

[elowami]

We have to hydrotest a heat exchanger, this exchanger used as ethylene vaporizer at -104C. This exchanger hydrotesting with methanol before which is not available now. Thus we are considering other mediums for hydrotest fluid. One idea floating around is to use nitrogen. I would like to know if anyone out there has expeience with hydrotesting in cryogentic area and if you have any suggestions.

Thanks.

 

[moltenmetal]

Are you proposing to hydrostatically test a vessel with liquid nitrogen? Please don't...use something which is a liquid, not a liquefied gas, at room temperature and pressure. The whole idea of a hydrotest is to reduce, to the maximum extent practical, the mechanical potential energy stored while the item is under test, because that energy would be released during a failure.

 

[EdStainless]

You didn't say it but I suppose that you want to test with a solvent in order to keep the unit clean and dry.
No, a liquefied gas is not a suitable test medium.
How is neither methanol or ethanol available? They are both very common industrial chemicals.
The only other things that I can think of are either far more expensive and.or more dangerous.

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P.E. Metallurgy, Plymouth Tube

 

[Compositepro]

Hydro with water for safety then flush with methanol to dry. It is not a good idea to do hydro with a flammable liquid. Glycols could also be used instead of water. But again, hydro with water is so much more convenient and less expensive.

 

[EdStainless]

The only time that I ever did a hydro with Meth was because it so much less expensive then UHP water. And should I mention that it was in a cold climate in the winter.....

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P.E. Metallurgy, Plymouth Tube

 

[georgeverghese]

Other liquids with low volatility and freeze point below -105degC are anhydrous ethanol (may be expensive at beyond 80%v/v), diethyl ether and dimethyl ether. Another commonly available liquid, acetone, has a borderline freeze point of -95degC. Also check out any HSE / handling /environmental disposal concerns. Agree MeOH may not be a good idea these days given its toxicity.

 

[moltenmetal]

DME is a gas at room temperature, so you should avoid that one too. Diethylether is too hazardous to even think about using as a hydrotest fluid. Stick with Compositepro's excellent advice.

 

[elowami]

thank you all for your cooperations