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[sabcoolin]

Hello,

 

I have a problem here, I am trying to design my vapor recovery system on my Ammonia rail car loading. I need to figure out how much vapor will be released at the given pressure.

 

The case is where i receive an rail car filled with nitrogen at 14.7psia. When i start filling the rail car at 80F and 235psia the ammonia will flash in the tank and nitrogen will compress in the tank. The valve on the vapor line is set to open at 175 psia. As more ammonia is fed to the rail car the pressure will keep on increasing in the tank. I my goal is to fill up the tank with 85% ammonia.

 

The vapor pressure of Ammonia at 80F is 153psia. Can someone please share your knowledge on how can i calculate the following

 

1. Does the pressure in the tank ever reach 175 psia assuming the temperature is constant at 80F? If it does reach then at what level of Ammonia in the rail car?

 

2. How much quantity of Nitrogen and Ammonia will escape the tank if the valve opens at 175psia?

 

My flash calculation says that with every 1 mole of N2 8 moles f NH3 will escape with N2.

 

Thank you for your help.