Liquid nitrogen to gas
Liquid nitrogen to gas
(OP)
Hi,
How to calculate how many BTUs it takes to convert one gallon of liquid nitrogen (LN2) into gas?
We use heat exchanger with 280F hot water. Output gas temperature 70F
TIA
How to calculate how many BTUs it takes to convert one gallon of liquid nitrogen (LN2) into gas?
We use heat exchanger with 280F hot water. Output gas temperature 70F
TIA





RE: Liquid nitrogen to gas
<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying " Damn that was fun!" - Unknown>>
RE: Liquid nitrogen to gas
Thanks
RE: Liquid nitrogen to gas
<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying " Damn that was fun!" - Unknown>>
RE: Liquid nitrogen to gas
Thanks
RE: Liquid nitrogen to gas
<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying " Damn that was fun!" - Unknown>>
RE: Liquid nitrogen to gas
<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying " Damn that was fun!" - Unknown>>
RE: Liquid nitrogen to gas
http://webbook.nist.gov/chemistry/
RE: Liquid nitrogen to gas
http://en.wikipedia.org/wiki/Nitrogen
At 74th year working on IR-One2 PhD from UHK - - -
RE: Liquid nitrogen to gas
Sorry for not getting back here sooner, just was busy with electrical problems.
Thank you for pointing me to the right direction, Google is really good source of information, but I did not find an answer to my question. I will keep looking.
RE: Liquid nitrogen to gas
RE: Liquid nitrogen to gas
Am I correct?
RE: Liquid nitrogen to gas
<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying " Damn that was fun!" - Unknown>>
RE: Liquid nitrogen to gas
It just for converging from liquid to gas. Now I need to warm up the gas from -319F to +70F at 100psi.
RE: Liquid nitrogen to gas
If I am not mistaken, the 85BTU you came up with will just be the energy for the phase change, right? You still need the energy to go from -319ºF to boiling (sub cooled liquid) and the energy after boiling to 70ºF (superheated gas)
Have you considered those? (I can't open the NIST page for some funky reason)
<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying " Damn that was fun!" - Unknown>>
RE: Liquid nitrogen to gas
RE: Liquid nitrogen to gas
RE: Liquid nitrogen to gas
Take the Btu/lb estimated by quark and multiply it by 6.71 lb/USG (@ 100 psia and -319oF) to obtain the requested Btu figure for one gallon of liquid nitrogen.
RE: Liquid nitrogen to gas
Warming the gas:
Q= 1.08 X CFM X (t1-t2)
1 gal of liquid nitrogen = 93.11 cubic feet
Q= 1.08 X 93.11 X (319+70) = 39117 Btu/gal of liquid or Btu/ 93.11 cfm of gas
Latent heat of vaporization
86.6 Btu/lb = 583.5 Btu/gal
Total: 39700 Btu/gal
According to Quark it suppose to be 182.72 Btu/lbm X 6.7347 = 1230.6 Btu/gal
I made a mistake somewhere, I think in the formula....
RE: Liquid nitrogen to gas
First, the formula deals with flow rate and not volume. Secondly, the formula is valid for atmospheric pressure (even you need to revise is for change in atmospheric pressures due to change in elevation). Third, it assumes sensible heat at 70F and thus valid for temperatures not far above and below it. Fourth and not very critical one is that it is for air.
Still, since air is mostly nitrogen, considering 0.24btu/lbF specific heat and .075 lb/cu.ft air density,
0.24x.075x93.11x(319+70) = 651.95 btu/gal, plus 583.5 btu/gl of latent heat equals 1235.45 btu/gal
RE: Liquid nitrogen to gas
Thank you for spending your time to explain all details of the process to me. I do not want spend any more of everybody's time on the issue.
The answer is : To convert one gallon of liquid nitrogen to the gas at 70F and 100 psi takes 1235.5 Btus
Again, thanks to everybody who helped me to find answer to the question.
Best regards
Chunia