I'm used to seeing cryogenic pipes insulated but maybe this is how regasification is normally done..there's a cryogenic line, client wants contents to vaporise downstream so it's uninsulated. A very thick layer of ice forms all around the pipe.
Common sense tells me that besides the added weight, the ice increases the equivalent modulus of elasticity of the pipe (similar to refractory lined pipe). Is there anything wrong with this logic?
Maybe if the pipe chills quickly and the ice mostly comes after the chilling it can be argued that there's little effect in the cold condition apart from weight. But if fluid flow stops and the pipe warms up the ice would then fight the return to neutral position. The ice will melt and crack but not before imposing significant loads i would think.
Does anyone have relevant design experience or counter arguments ?
cheers
Martin

If the section of the line in question is not needed to be flexible to be code compliant, you certainly can (and should) treat it as stiff to fulfill your needs.

As always, our task is not to simulate reality perfectly, but rather estimate stresses conservatively enough that we provide sufficient evidence of the safety of our approach.

To that end, I would not attempt to estimate the stiffness of ice but rather insist that weaker flexible piping components (i.e. elbows and tees) not be encased in ice in a configuration.

Demand that these components be protected if they're placed in a vulnerable position.

Also note that the thermal expansion of ice is 10x that of steel, which can get you into further trouble, depending on your configuration.

Aside from load effects there's also corrosion from standing water, drainage, and the safety hazard of falling ice to both to equipment and personnel to deal with. And that's just the naturally occurring stuff.

Come to think of it, isn't there anti-sweat insulation for this purpose? Or am I thinking of something else?

Hello,
Generally cryogenic lines are of SS material.
For non insulated cryogenic line you need to add ice thickness and ice density under insulation & insulation density Tab!
ice density if not given can be assumed around 970 kg/m3
Regards,
Nitin Lonkar