Emergency water line purge with compressed air/gas

[Icecoffee]

Hi all,

I would like to ask for advice for the following issue...

My project is a process cooling water for equipment in our plant and this problem applies to cryogenic equipment...

The process water is delivered to the equipment which has internal cooling coils, if there is a power failure/water stoppage, water can remain stagnate in the coils and will freeze up (therefore expand and rupture the coils), I am trying to find a way to deal with this emergency situation.
I am wondering if say, injecting plant compressed air (90 psig) /nitrogen (60 psig) into the water lines (all about 3/8" to 3/4") and try to "push out/purge" the stagnate water is something possible, and if so, how do I calculate how much cfm air/gas, pressure, and how do I install this? (three way valves at inlet and discharge...?)
Any suggestions and advise will be greatly appreciated.

 

[EdStainless]

I take it that no one considered 'self draining' installations?
Air blowing is problematic as often it results in only partially empty systems. You might get better results if a series of valves isolated sections of the system before blowing.
It takes a lot of air because you have to blow for a while in order to remove most water.

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