Specific Gravity of LNG

  1. 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 cant 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.
     
  2. jcsd
  3. Borek

    Staff: Mentor

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

    Staff: Mentor

    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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