Safety aspects of the use of LNG for marine propulsion

Liquefied natural gas (LNG) as a fuel shows a large energy to volume ratio. In addition, its combustion is characterized by low levels of production of CO2, SOX, NOX and particulate matter in comparison to conventional fuels. To reduce the emission of SOX into the atmosphere the sulphur content of heavy fuel oils used for marine propulsion will be restricted in the near future. However, LNG is a combustible cryogenic liquid and as such presents specific safety hazards. The large scale use of LNG in the marine sector requires appropriate transport, storage and transfer facilities. The risks connected with the operation of these facilities are analyzed. Specific safety characteristics of the equipment involved are incorporated in the analysis. Safety distances are determined based upon a study of the effects of accidents during which LNG is released. It is found that the pressure at which LNG is released during an accident greatly influences the effect distances. At pressures near atmospheric, the hazards of LNG are comparable to those of conventional liquid fuels such as gasoline. At higher pressures, it behaves more like a combustible gas liquefied by compression