presso
Chemical
- Feb 12, 2004
- 25
I'm reviewing flow compensation factors for gas mixtures and I came accross a few inconsistencies on the composition compensation. The formula used is :
((P/Pref)(Tref/T)(G/Gref))^0.5
with G and Gref defined as the specific gravity OR molecular weight.
The composition of the gas varies moderately but it varies. I have a spreadsheet designed to calculation the density of our typical blend gas mixtures as a function of the density but can I use instead the molecular weight calculated as MW = x1MW1 + x2MW2 + ... + xnMXn with some accuracy? I'm kind of bothered by the fact that the density calculations is quite complex (starting with critical properties of various components and so on) as opposed to the MW calculation that is very very simple?
Also is it correct to calculate the spec. gravity of a gas mixture this way : S.G. = MW/(Z*29), 29 beinng MW for air I assumed?
Thank you!
((P/Pref)(Tref/T)(G/Gref))^0.5
with G and Gref defined as the specific gravity OR molecular weight.
The composition of the gas varies moderately but it varies. I have a spreadsheet designed to calculation the density of our typical blend gas mixtures as a function of the density but can I use instead the molecular weight calculated as MW = x1MW1 + x2MW2 + ... + xnMXn with some accuracy? I'm kind of bothered by the fact that the density calculations is quite complex (starting with critical properties of various components and so on) as opposed to the MW calculation that is very very simple?
Also is it correct to calculate the spec. gravity of a gas mixture this way : S.G. = MW/(Z*29), 29 beinng MW for air I assumed?
Thank you!
