As part of the project assessing the hazards involved in the transport and handling of liquefied natural gas (LNG-project) the dispersion of methane gas clouds in the atmosphere was studied. Calculations for an instantaneous, continuous, and time-dependent source were made. Starting from Pasquill's method, and taking into account the source dimensions, the amount of gas in the explosive region (5 to 15% v/v) was calculated. For an instantaneous cloud this amount shows a maximum of approximately 50% irrespective of the source length and meteorological conditions. Special attention was paid to the calculation of the safety distance for a quasiinstantaneous spill on the sea. For this case the behavior of the cloud at the source was numerically simulated. For a 25,000 cubic meter spill of LNG this leads to a distance where the average concentration is half the lower flammability limit of approx. 20 km under unfavorable meteorological conditions and a 7 km under favorable meteorological conditions. The possibilities of the continuous and discontinuous measurement of methane concentrations were investigated. A device was built to generate 0.5 to 50% concentrations of methane in air. The accuracy of the concentrations was checked with infrared spectroscopy. The performance of a commercially available combustible gas detector to measure the methane concentration continuously and the use of gas chromatography as a discontinuous method were investigated.

  • Corporate Authors:

    National Defence Research Organization TNO

    Chemical Laboratory
    Rijswijk,   Netherlands 
  • Authors:
    • Vanbuijtenen, CJP
    • VERWEIJ, A
    • Boter, H L
  • Publication Date: 1976-9


  • Dutch

Media Info

  • Pagination: 24 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00185742
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: CL-1976-16, TDCK-68902
  • Files: TRIS
  • Created Date: Dec 29 1979 12:00AM