Mechanism Of Protective Layer Around Storage Tanks Against Blast Fragments And Risk Pre-control

The clustering distribution of process equipment in the chemical industrial park(CIP)usually leads to high risk level.In CIPs,an explosive accident in one unit may generate projectiles,which can damage the adjacent units and cause disaster escalation.This is one of the main causes of domino effects.The target unit protection is an effective measure to cut the accidents escalation and mitigate the damage of the structures,and protective layer technology is the specific one.In order to explore the degree to which the protective layer could mitigate the risk,the protective mechanism of the protective layer against blast fragments are explored from the aspects of damage degree and failure probability.The main contents of this paper are as follows:(1)Experiments study on small-scale storage tank considering protective layer under impact of blast fragment.The projectiles with high kinetic energy are obtained to simulate blast fragments.A high-speed camera is used to record the initial and residual velocity of the projectile with different protective layers,and the energy of the projectile penetrating the target could be calculated.The deformation and perforation of tanks and protective layers are analyzed,and the failure law of tanks impacted by projectile under different protective layers is also studied.(2)Numerical analysis of storage tank considering protective layer under impact of blast fragment.Dynamic response of chemical storage tank with protective layer or without are compared based on LS-DYNA.It is found that the protective layer had a significant effect in damage mitigation of target tank.By comparing the deformation,structural displacement,stress and energy change of the tank,the degree to which protective layers could mitigate the damage triggered by blast fragment is investigated,and the influence of the protective layer parameters on the dynamic response of the tank is analyzed.Besides,the mechanism of the protective layer and the degree to which different protective layers reduce the severity of accident consequences can be obtained.(3)Vulnerability analysis of storage tank considering protective layer under impact of blast fragment.The energy dissipation model of blast fragment and the failure probability model of target tank under the protection of multi-layered protective layer are established.Monte-Carlo simulation method is used to analyze the vulnerability law of the target tank under impact.The maximum failure probability of the target tank with or without protective layer are compared.By plotting the vulnerability curves and surfaces of target tank,the degree to which the protective layers with various thickness,number of layers and coupling modes reduce the failure probability is explored.(4)The engineering application example of protective layer technology based on risk prevention and control.The economic loss of the consequences in different accident scenarios is calculated.Combining the accident loss with the failure probability of tank,the risk level of accidents triggered by blast fragments with protective layer or not are analyzed;Combining the accident loss with the safety investment,the effects of different protective layers on safety of the storage tank are analyzed.Selection directions of the risk prevention and control technology of the protective layer suitable for the actual project are finally put forward.