DISPERSION AND ANALYSIS OF METHANE IN THE ATMOSPHERE

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

Language

• Dutch

Media Info

• Pagination: 24 p.

Subject/Index Terms

• TRT Terms: Atmosphere; Clouds; Concentration (Chemistry); Cryogenic materials; Explosions; Fires; Flammability; Fluidity; Hazardous materials; Hazards; Liquefied natural gas; Methane; Risk analysis; Safety; Storage facilities; Transportation
• Old TRIS Terms: Atmospheric composition; Cryogenic fluid storage; Gas explosions
• Subject Areas: Safety and Human Factors; Transportation (General);

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