I am trying to calculate a cost per hour use of a gas we buy in a cylinder. The details I have been working with are:
N, density =
1.251 g/L @ 0.101 MPaM (molar mas) =
- Gas cylinder: Pressure =
20 MPaCylinder volume
- Operating pressure of gas from cylinder =
0.45 MPaand flow rate =
I have been applying the ideal gas law to
PV=nRT to figure out how many total litres of N are in the can at 4.5 bar pressure to then get a rough estimate of how many hours of flowing gas I get. However I seem to be getting unreasonable numbers, potentially from me using the equation or reasoning incorrectly:
When I apply the gas law under isothermal
V2=V1/(P2/P1) conditions to see how much the internal gas volume expands from the 20 MPa pressure, as a sanity check I wanted to see how many L at 1 atm came out. The result was 1.89 ML which makes little sense as the conversion of 1.89 ML N2 to mass = 2.364 Mg.
Similarly it equates to 420 kL @ 0.42 MPa.
Where am I going wrong?
Maybe the specifications mean that its 9.45m3 or 9450 L of compressed gas to 200 bar?