Nitrogen drain lines 1

amirparviz:

I don't know if you are aware that your use of the word "drain" implies that you are dealing with a liquid (liquid nitrogen -LIN -in this case). LIN is a cryogen and, as such a hazard because of it's asphyxiating properties and it ultra-low temperature. If your "gas plant" is an air separation column (or something similar), then the conventional manner of evacuating the cryogens (especially LIN) is to route the liquid fluids to an outside, safe and isolated area through a provisional pipe or tubing (preferably copper) and allow them to vaporize outside and return to the atmosphere as a gas.

You certainly should not be routing any cryogen to a conventional process drain in the floor or at grade. If you give us basic data and a reasonable explanation of what you are doing, we won't have to guess at it and it will take far less time to give you an educated answer instead of a guess.

If your talking about Nitrogen Gas, I would put drain valve at the low points, simply as a matter of practice. Will they be doing a hydrotest on the line? if so, there will need to be low point drains for that, and it's just as easy to keep them. The nitrogen gas should not have any condensate forming in it, but is the risk that there is something condensed in it worth the rist of not having low point drains?

Many thanks for all reply
The nitrogen is not in liquid phase it is gas. For more information please advise the nitrogen has these conditions in producing nitrogen unit battry limit:
Operating pressure
Pmin=6.7 Pnormal=7.7 Pmax=9 Pdesign=11 all barg
Tmin=10 Tnormal=57 Tmax=65 Tdesign=80 all C

In "technip company" PIDs I saw for the user point of 1" nitrogen line there is 1/2" bleed line just like configuration that is used for steam line.
Perhaps it would be mistake? or nor?