Need help sizing N2 filling bottles for gas bottle precharging. Simple
Need help sizing N2 filling bottles for gas bottle precharging. Simple
(OP)
I think I am just running my own mind in circles with this one, but I feel like I would ask you guys before committing to anything.
I need to find out how much 2,200 psi nitrogen is needed in order to precharge (3) 15 gallon gas bottles with 1,200 psi of pressure each. The place we can order the nitrogen sells them in 20, 40, 80, etc. cubic feet of nitrogen at 2,200 psi. My calculations yielded that for 45 gallons (45*231= 10,395 cu in) @ 1200 psi, I would need 12,474 cu in (or 7.22 cu. ft.) of 2,200 psi nitrogen to attain this precharge. It seems low to me. Keep in mind that the 2,200 psi bottles can only be depleted to 1,200 psi, so basically only 1,000 psi of that pressure is usable.
Thanks in advance!
Tell me if any more information is necessary.
I need to find out how much 2,200 psi nitrogen is needed in order to precharge (3) 15 gallon gas bottles with 1,200 psi of pressure each. The place we can order the nitrogen sells them in 20, 40, 80, etc. cubic feet of nitrogen at 2,200 psi. My calculations yielded that for 45 gallons (45*231= 10,395 cu in) @ 1200 psi, I would need 12,474 cu in (or 7.22 cu. ft.) of 2,200 psi nitrogen to attain this precharge. It seems low to me. Keep in mind that the 2,200 psi bottles can only be depleted to 1,200 psi, so basically only 1,000 psi of that pressure is usable.
Thanks in advance!
Tell me if any more information is necessary.





RE: Need help sizing N2 filling bottles for gas bottle precharging. Simple
Charged to 2200 psi, that's 1100 Cu Ft of free nitrogen.
A.
RE: Need help sizing N2 filling bottles for gas bottle precharging. Simple
Density(stp)=0.076 lbm/ft^3
Density(1215 psia)=6.308 lbm/ft^3
deltaMass=(6.308-0.076) lbm/ft^3 * 6.016 ft^3=37.49 lbm
Vol(stp)=deltaMass/Density(stp)=493 SCF
The density of the supply bottles is immaterial.
David
RE: Need help sizing N2 filling bottles for gas bottle precharging. Simple
RE: Need help sizing N2 filling bottles for gas bottle precharging. Simple
Now if you own the supply bottles, the trick is to use them wisely. Fill from 0 psig to 800 psig with nearly depleted bottles, then top them off with 2,200 psig bottles for example.
Regardles, it is going to take 37.5 lbm of nitrogen to get your 3 bottles to 1200 psig. If for some perverse reason you wanted ACF at 1200 psig then divide mass by actual density and get 5.94 ACF, but there really isn't much you can do with that number.
David