Investigation propagation of blast waves on storage tank farm and the importance of safe distance and position of storage tank

The most important danger that threatens a petrochemical refinery is an explosion, which is followed by a fire or vice versa. In fact, the occurrence of initial events such as explosions and fires spread from one part to another like the domino effect if the distance between the storage tanks is not sufficiently considered. Therefore, the distance and arrangement of petrochemical storage tank can play an important role in reducing the damage of initial accidents. So far, due to the explosion uncertainties, no definitive solution has been offered, but a combination of active and passive techniques such as the efficient use of intelligence and security organizations, increasing the scaled distance between the detonation point and the target buildings or providing physical barriers, the use of deformable materials to absorb energy, and the use of appropriate retrofit structural techniques can reduce the effects of explosions. As it turns out, it is virtually impossible to study the propagation of blast waves experimentally on a large scale due to financial constraints and potential hazards. Therefore, to solve this problem, two solutions are proposed: the use of small-scale laboratory methods and the use of numerical methods. Three-dimensional numerical analysis is an efficient method for investigating structural weaknesses, hazard risk analysis, and evaluating of explosion hazard points. In this study, with the help of explosion simulation by Eulerian-Lagrangian coupling method, the research has been surveyed in two parts. In the first part, petrochemical tanks in different arrangements, and,at different distances from each other are modeled in 3D on Autodyn software on the scale of and the propagation of explosion waves and the confinement of 8g of TNT pressure in the environment between the tanks are investigated. In the second part, the effect of barrier shape on reducing the blast pressure of 1000 kg of TNT on a real scale has been investigated. The results show that the use of semi-empirical relation in UFC-0-340-02 to determine the blast pressure is applicable only to open environments, and it is not precise in closed environments due to the confinement of the blast pressure. Moreover, the results show that it is not conservative to use the required distance between tanks considering the amounts proposed by the regulations. As a result, increasing the distance up to twice the amount proposed by the regulations, the effect of explosion pressure confinement is eliminated. The best way to position the tanks in this study is a zigzag pattern with a distance equal to twice the safe distance between the tanks in accordance with NFPA-30. In addition, the results show that by creating a barrier against the explosion, the explosion over-pressure can be greatly reduced, but the shape of the barrier does not have much effect. Although, using the Eulerian-Lagrangian coupling method requires considerable time and appropriate software to perform the calculations, it provides a comprehensive understanding of the blast wave interaction with structures. With the advancement of technology and the use of parallel processing in the cloud space, and the mapping technology it is possible to evaluate the different structures on a real scale against the explosion.