3 replies to this topic

[Devanand Telgote]

Hi,
I want to calculate the amount of Boil off Gas Generated in Ammonia Storage Tank. 
1. The Ammonia storage tanks will have proper insulation system to the service, designed and mounted for a maximum daily boil off gas of 0.04% by weight.
2. Atmospheric pressure changes are considered to be 15mbar. for max. BOG calculation.
3.Ammonia Rundown to tanks.
4.Heat Leaks.

[Bobby Strain]

Looks like you you have all the information that you need. Except for barometric pressure rate of change. Which you should get for your location.

 

Bobby

[Devanand Telgote]

Thanks for your reply 
Can you please tell me how can I calculate Boil off gases generated due to Atmospheric changes? The tank is closed. and The initial composition is Ammonia-99.9%, water-0.08%, other-0.02%. The initial temperature and pressure conditions are- T= -33C, P= 0.02 bar guage, Flowrate = 100833 kg/h. At what rate will be the vapours generated if atmospheric pressure changes are up to 15 mbar in an hour of operation. Assume temperature to be constant.

[S.AHMAD]

Hi Dev.

My understanding about BOG is that the effect of rundown temperature and ambient temperature are the contributing factors not so much on ambient pressure . The BOG rate is determined by energy balance, normally the effect of pressure on enthalpy is small and negligible.

However, variation in ambient pressure is essential for determining the correct design pressure of the storage tank.

 

Hope above comment helps.

 

S.ahmad

Edited by S.AHMAD, 03 June 2016 - 08:20 AM.