Atmospheric Storage Tank Explosion Modeling

Many flammable products are usually stored in large vessels at atmospheric pressure. Ignition of an hydrocarbon-air mixture in such tanks can lead to an explosion and cause lethal casualties, as in 2006 at Partridge-Raleigh oilfield, USA, or damage the surrounding facilities and buildings. To prevent that, safety distances shall be defined. Several simple methodologies have been published allowing the calculation of safety distances. The study compares results from simple methodologies with more sophisticated calculations. Three-dimensional simulations of gas explosions using the CFD code FLACS have been performed to define a typical pressure load profile to apply on the inner side of the vessel's walls. The structural response of the tank (deformation and displacement), under the loading condition previously obtained, has been computed with LS-DYNA. Consequently, we have been able to justify that some of the assumptions used in simple methodologies are not relevant. We also have established specific input data that should be used in order to obtain a reasonably conservative estimation of the safety distances.