ortabe
Mechanical
- Feb 6, 2009
- 21
Hi,
Background:
AGA PAR NX-19 is an equation of state applicable to some compositions of natural gas for estimating the compressibility z. The required input is:
p, T, mol% CO2, mol% N2 and d
where d is the density relative to air (I assume this is at 1 atm). d is often not known or at least not provided.
Case:
From a known d (0.65) for a given composition, the calculated sum(comp1_mol% * MW1 + comp2_mol% * MW2 ...)/avg_MW_air = 0.62, which is off by 5%.
Question:
What would be an accurate way to determine d when only the composition is known? Is the above under Case 'good enough'?
Background:
AGA PAR NX-19 is an equation of state applicable to some compositions of natural gas for estimating the compressibility z. The required input is:
p, T, mol% CO2, mol% N2 and d
where d is the density relative to air (I assume this is at 1 atm). d is often not known or at least not provided.
Case:
From a known d (0.65) for a given composition, the calculated sum(comp1_mol% * MW1 + comp2_mol% * MW2 ...)/avg_MW_air = 0.62, which is off by 5%.
Question:
What would be an accurate way to determine d when only the composition is known? Is the above under Case 'good enough'?