(120a) Experimental Study of Effective Water Spray Curtain Application in Controlling Lng Vapor Clouds

The installation of new LNG storage facilities in the US to meet the demand of natural gas has brought increasing attention to LNG safety issues. Because of its highly flammable nature, LNG poses several hazards to workers, properties, and the surrounding communities. One of the major hazards is the formation of a flammable vapor cloud from any accidental LNG release, which may result in a massive fire. The safety measures to prevent and mitigate an accidental LNG release are essential and critical to protect the employees and the public from injury or harm.

The water spray curtain is currently recognized as a promising technique to control and mitigate many toxic and flammable vapors. Much theoretical and experimental work has been carried out to determine the effectiveness of the water spray curtain in dispersing heavier vapor. However, LNG vapor dispersion behaves differently from other dense gases due to its low molecular weight and extremely low temperature. In this context, it is essential to carry out research to understand the effects of water curtain on LNG vapor clouds. There have been a very limited number of publications on the use of a water spray curtain to mitigate LNG vapor clouds. These previous studies show that water spray curtains can enhance LNG vapor dispersion from small spills. However, in order to develop comprehensive and structured engineering guidelines for the design of an effective water spray curtain for controlling LNG vapor many key questions still remain to be answered.

An experimental methodology to study the LNG vapor dispersion behaviors with the application of water spray curtain is presented in this paper. This field experiment involves the fundamental study of forced dispersion, dilution due to air entrainment, and heat exchange to determine the effectiveness of water spray in reducing the LNG vapor ?exclusion zone?. This paper discusses and outlines the method and the results to emphasize the observed effectiveness of water spray curtain on LNG vapor dispersion.