EVALUATION OF CAPACITANCE DENSITOMETRY FOR LNG MIXTURES WITH LOW NITROGEN COMPOSITION

Densities of typical LNG mixtures under saturation and subcooled conditions were calculated using a computer program which uses the method of corresponding states. The dielectric constant for each mixture was determined from the Clausius-Mosotti relationship assuming the excess CM function is zero. Examination of the resulting density-dielectric constant plots shows that for fixed nitrogen composition a nearly linear relationship exists between saturation density and dielectric constant under isobaric or isothermal conditions, independent of the hydrocarbon mixture. The results show, however, that the effect of the nitrogen composition on this linear relationship may be taken into account partially by a measurement of the mixture temperature. For the range of mixtures of this study it is possible to determine density to + or - 0.3% independent of knowledge of the hydrocarbon composition from an exact measurement of dielectric constant and temperature. Further improvements can be made if the fraction of nitrogen is known.

• Supplemental Notes:
  • Sponsored in part by Maritime Administration, Washington, D.C. Pub. in Ind. Eng. Chem. Process Des. Dev., v16, n3 p330-336 1977.
• Corporate Authors:

  National Bureau of Standards

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  Washington, DC  United States  20234

  Maritime Administration

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  Washington, DC  United States  20590
• Authors:
  • Giarratano, P J
  • Collier, R S
• Publication Date: 1977

Media Info

• Pagination: 7 p.

Subject/Index Terms

• TRT Terms: Chemical composition; Density; Dielectric properties; Hydrocarbons; Ignition systems; Ions; Liquefied natural gas; Mixtures; Natural gas; Nitrogen; Numerical analysis; Solutions (Chemistry)
• Old TRIS Terms: Charged particles; Density mass/volume; Lng ignition; Lng properties data; Solutions
• Subject Areas: Marine Transportation; Safety and Human Factors;

Filing Info

• Accession Number: 00168788
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: Final Rpt.
• Files: TRIS, USDOT
• Created Date: Dec 27 1978 12:00AM