What is the specific gravity of LNG at 5 bar and -134 deg C?

[nikcosmo]

Hi Everyone...

I'm trying to calculate the specific gravity of a sample of LNG using a compostion certificate and temperature and pressure variables of 5 bar at -134 deg C saturated. Its do perform a check for the value used to calculate how much is charged per litre by converting density to litres. The density should be around 0.4 kg/m^3 but i can't seem to get a close answer to that using the ideal gas equation, pv = nrt.

Infor on composition certificate;
Gas composition;
Nitrogen ; 1.18%
Methane; 96.66%

Gas density at 15 deg C = 0.699 k/m^3
Ave MW = 16.487 g/mol

Can someone please help? thanks.

 

[Borek]

pV=nRT is and ideal GAS equation, LNG is a LIQUEFIED natural gas. You can't use theory that describes gaseous state to liquid state.

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[nikcosmo]

Any suggestions to which way i should approach it then? cheers.

 

[Borek]

Only approach I can think of is to find density tables for LNG, engineering handbooks should have these. There are no theoretical equations that would allow calculation of density of a liquid (and even when such equations exist, they make heavy use of experimentally determined coefficients - so we are back to the handbook and tables).

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