Numerical Investigation of LPG Leakage Dispersion and Explosion Consequences in a Spherical Tank with Safety Walls

Abstract Liquefied petroleum gas (LPG) leakage from spherical tanks can generate near-ground flammable vapor clouds and subsequent fire and explosion hazards. A three-dimensional FLACS model of a 1000 m3 LPG spherical tank was established to investigate the effects of safety-wall geometry on vapor-cloud dispersion and explosion consequences under quiescent atmospheric conditions. Nine wall configurations were evaluated in terms of dispersion distance, equivalent flammable-cloud volume (Q9), explosion overpressure, and temperature. The safety wall restricted outward vapor-cloud migration but promoted accumulation along its inner side. Wall height and tank-to-wall separation distance exerted more pronounced effects than wall thickness within the investigated range. Case M2, with a wall height of 0.9 m and a separation distance of 3 m, produced the highest Q9max, Pmax, and Tmax, reaching 20.76 m3, 0.0133 barg, and 2202.02 K, respectively. Increasing the ignition delay from 5 to 180 s increased Pmax from 0.0101 to 0.0130 barg because of continued vapor-cloud accumulation. Among the investigated configurations, a wall height of 0.6 m combined with a separation distance of 5 m provided the most favorable balance between limiting outward dispersion and reducing local accumulation and explosion overpressure.