Water Curtain Application for Forced Dispersion of LNG Vapor
Morshed Rana and M. Sam Mannan. Chemical Engineering, Mary Kay O'Connor Process Safety Center, Texas A&M University, College Station, TX 77843
Water curtain is currently a recognized technique to control and mitigate various hazards in the process industries. It has been used to absorb, dilute and disperse toxic or flammable vapor clouds, as well as to reduce heat radiation in case of vapor cloud fires. Water curtain has also been suggested as one of the economic and promising LNG vapor cloud control techniques. It is expected to create an effective barrier to reduce the “vapor cloud exclusion zone”. Observations of the interaction of LNG vapor clouds with water spray curtains clearly demonstrate some enhanced dispersion. Detailed analysis of the complex mechanisms and the effect of important water spray features have not been studied experimentally in previous research. This paper presents a research methodology to study the physical phenomena involved and the effect of water curtain parameters during LNG vapor and water curtain interaction. The data from medium scale out-door experiments at the Brayton Fire School, Texas, are analyzed to understand the relative importance of induced mechanical mixing effects, dilution with air, and heat transfer between water droplets and the LNG. Analysis is presented in the paper to determine the effect of common types of water curtains in dispersing LNG vapor cloud effectively during an accidental release of LNG.