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[MJ94]

I have recently joined a N2 Plant , Liquid Nitrogen produced can be accumalated in either of the 2 LIN vessels , Nitrogen Header Pressure to be maintained is 5.5kg/cm2 and Pressure of MP colum is around 7 Kg/cm2 , for LIN vessel recieving Liquid Nitrogen Rundown to maintain flow from the MP column , a slight atmospheric venting is maintained , to keep pressure below 7 kg/cm2 . I feel this venting is really a waste of money .

 

Is this done in other Nitrogen plants as well , can it be avoided.??

[Bodhisatya]

Although it a waste of money ,it's unavoidable.You need to have a minimum pressure gradient for flow to travel from one region to another.Generally a delta P of 0.5 bar is maintained between MP Column and the tank.

 

There is no way you can avoid,although it can be reduced.To prevent flashing of LIN which leads to pressure rise in tanks,one can use Super Insulated  Vaccum Line for delivery from Cold Box to Tank.During design stage incorporation of LIN subcoolers will also help in reducing flashes.

 

Regards

Bodhisatya.