Nitrogen in LPG Tank

[RFZC]

We have taken LPG's sample (vapor) from the top of the tank and we have found a significant value of nitrogen.


1 The presence of nitrogen can affect the conditions of storage (pressure/temperature)?
2 Do we have to purge it totally?
3 If yes, which is the best method?
4 Which is the best method to detect nitrogen?

Thanks for your comment and help

 

[saldanha]

I think you need to find the origin of N2 first. as far as i know their should not be a lot of N2 in LPG.
If your LPG is used for heating the presence of N2 may affect you heating process. this only if the N2 is allowed to mix with le vaporised LPG.

 

[RFZC]

Saldanha:
we received lpg by ship and unloaded by truck. We suppose that the N2 comes from the ships and trucs (line of return from the loading facilities).
We don't use LPG, only store it (300 m3 of capacity)

 

[Montemayor]

RFZC:

1. The presence of a non-condensable (such as N2) will cause your storage pressure to increase. We don't know how you receive the LPG or how it is getting in your LPG. Is it accumulating? Or is only appearing from time to time? Some N2 may dissolve in the LPG, but I think it would be a small quantity.

2. You are in a better position to decide whether to purge it or not. Is it affecting your operation? Is your tank facing an over-pressurization hazard? You haven't told us enough basic data to comment on this.

3. See #2.

4. You say you've already detected a significant value in your tank. What method were you using? Don't you have faith in your analytical methods or do you want to compare?

We just don't have enough basic data. We don't know if you're using the LPG as a liquid or as a vaporized gas. If you're using the liquid, does it affect your downstream process. If you're using it as a fuel, I doubt it. You don't even tell us if the tank you're sampling is the main storage or a process tank. We need more data to generate specific answers.

Art Montemayor
Spring, TX