LNG trench dispersion modeling using computational fluid dynamics

Quantifying the size of flammable vapor cloud hazards associated with an accidental release of Liquefied Natural Gas (LNG) into a spill containment system supported by narrow drainage trenches has posed a modeling challenge since the inception of the LNG industry. Early attempts to treat the vapors evolving from the trenches included using line-source Gaussian models, and the use of the DEGADIS model by modeling “segmented” trench elements and adding the contributions from each trench segment at a specified downwind distance. These approaches often are only reasonable for a select set of conditions (e.g., winds perpendicular to the trench) and have no ability to simulate many of the conditions that might result in a larger potential impact (e.g., winds blowing parallel to the trench).