Liquefied Natural Gas Vapor Hazard Mitigation with Expansion Foam Using a Research-Scale Foam Generator

The flammable vapor cloud is the primary hazard caused by a liquefied natural gas (LNG) spill on land. If it is not properly mitigated, an ignition of the vapor cloud will result in a fire or explosion hazard. High expansion foam is recommended by NFPA 11 and NFPA 471 for LNG spill hazards mitigation. This work studied the physical interaction of the LNG and expansion foam system using a foam generator and a foam test apparatus that are built in-house. The performance of the foam generator was characterized in terms of the foam expansion ratio and generation rate. The temperature profile in the foam zone quantitatively confirmed the warming effect of foam on LNG vapor. The foam breaking rate was determined at the initial stage and steady state. The boil-off effect was studied quantitatively with more details using this novel foam generator. The vapor channel formation and vapor concentration were also investigated for the mitigation effect.