The LNG Custody Transfer System (CTS) measures the quantity of product loaded or discharged from LNG tanks. Typically, present day ships will take on LNG in quantities of 125,000 cu m so that at current prices, the delivered cargo of just one load represents a value in excess of $5M. Thus, an improved measure of accuracy--say, of 0.1 percent--represents a potential saving of $5,000 on each voyage. If the tank geometry is accurately recorded and certified, the volume can be accurately determined by measuring the cargo level at the tank bottom and again at the top before and after loading. The existing gas contracts require that the custody transfer system measures the level in each tank to an accuracy of plus or minus 7.5 mm, or 0.03 percent in a 25 m tank. The direct density measuring system will measure the density of the liquid to an accuracy of plus or minus 0.2 percent, independent of the cargo composition. These values are recorded either by an automatic data logging printout or hand recorded from direct reading of a digital display. Finally, a sample of the LNG is taken for composition analysis. With the values of level, density, and composition known, the mass and heating values can be determined and the total Btu calculated. Also described are the Custody Transfer level and density measurement as well as the operation of the display and control unit.

  • Corporate Authors:

    IPC Industrial Press Limited

    Dorset House, Stamford Street
    London SE1 9LU,   England 
  • Authors:
  • Publication Date: 1977-11-18

Media Info

  • Pagination: p. 29-31
  • Serial:
    • Marine Week
    • Volume: 4
    • Issue Number: 44
    • Publisher: IPC Business Press Limited

Subject/Index Terms

Filing Info

  • Accession Number: 00172834
  • Record Type: Publication
  • Source Agency: Marine Week
  • Files: TRIS
  • Created Date: Apr 12 1978 12:00AM