4 replies to this topic

[Zauberberg]

Greetings from Equatorial Guinea,

I need some information about liquid Nitrogen systems - particularly the details about liquid Nitrogen storage conditions (pressure, temperature) and connection with the existing (gaseous) Nitrogen distribution system. In addition, some tips on liquid Nitrogen storage tank and vaporizer design would be very much appreciated.

We are planning to purchase Nitrogen liquefaction skid and provide storage tank for cryogenic liquid that will be used for equipment purging during plant shutdowns. The plant operates 3 PSA units for Nitrogen production which is sufficient for normal operation, but the available quantity of Nitrogen is not sufficient for equipment purging during plant S/D - or better to say it causes very extended purging time which translates into days of lost production. On the other hand, during normal operation PSA units always have an extra/unused Nitrogen production capacity, and our idea was to take this extra production of N2, liquefy it, store it and keep it under cryogenic conditions so as to have a separate supply of N2 when the plant is shutdown. This would reduce the timeframe required for equipment purge due to availability of higher quantities of N2.

What are the "usual" liquid N2 storage conditions, and how this system is connected with the existing (PSA discharge) plant Nitrogen distribution system? Also, is there any recommended manufacturer of these skids?

Best regards,

[breizh]

Hi ,
For the suppliers I would recommend either Air liquid, Praxair or Air Product .

Hope it helps
Breizh

http://encyclopedia....RD28=81&RD29=82

[Qalander (Chem)]

Dear Zauberberg Hello/Good Afternoon,

You might see my reply on the similar issue under discussion in these forums, some two to three weeks back, that contained some relevant info on the subject.

However it was also our practice at the previous employers to have a relatively smaller liquid Nitrogen storage vertical shaped (it had double walled vacuum insulated design).

Additionally large cylindrical bullet storage was also there at high pressure but near ambient temperature(s).

Hope this does help in some way.

[breizh]

Hi Zauberberg ,
For the working condition , the nitrogen liquified is stored at a pressure of 7 to 8 bar g and the unit is equipped with 1 or 2 evaporators .

Regards
Breizh

[Qalander (Chem)]

Hi Zauberberg ,
For the working condition , the nitrogen liquified is stored at a pressure of 7 to 8 bar g and the unit is equipped with 1 or 2 evaporators .

Regards
Breizh

Dear breizh, you are correct;

at our previous employer(s), if recalled correctly,

we had two evaporators one 'primary' or built-in & other secondary or 'Auxiliary' capable of higher evaporation rate(s) as per needs.

Somewhat similar liquid Nitrogen storage pressure(s).

Edited by Qalander (Chem), 16 November 2009 - 12:52 PM.