Modeling of LNG spills into trenches

A new method for the analysis of LNG spills into trenches has been developed to quantify vapor dispersion hazard distances. The model uses three steps to capture the behavior of an LNG spill into a trench. The first is to analytically calculate the evolving LNG flow, the second to calculate the vaporization rate along the trench, and the third is to calculate the dispersion of the vapors using a CFD model that has been validated for this application in the presence of complex geometries. This paper presents case studies that show the effect of wind perpendicular and parallel to the large aspect ratio trenches on vapor dispersion. The case studies also demonstrate the effect of complex terrain and obstacles such as vapor fences on vapor dispersion. The simulations show that wind direction relative to the trench has a significant effect on cloud shape, height, and maximum downwind distance. The addition of vapor fences to mitigate vapor dispersion hazards from an LNG spill into the LNG containment trench is shown to be effective. (C) 2010 Elsevier B.V. All rights reserved.