The Stress Analysis And Risk Research Of 2000m~3 Ethylene Spherical Tank

Petrochemical industry belongs to high-risk industry, in recent years, the spherical tank as a storage container, with the advantages of strong carrying capacity, using less steel and small area, gradually enlarged and developed industrial park. In the process of petrochemical production, the materials are typically involved an inflammable, explosive, toxic, corrosive characteristics, which prone to fires, explosions and other serious accidents, brought he great convenience and benefits at the same time the greatest threats on the human life. So people also given its due attention to its security problem. The research on spherical tank system quantitative risk assessment can provide a basis for the dangerous chemicals storage and transportation industry to adopt effective measures to avoid or reduce accidents, which can promote enterprise the stored process intrinsically safe, incident emergency handling capacity and reduce petrochemical production accidents. The main contents of the paper are as follows.First, risk analysis is made based on the structure characteristics of the ethylene spherical tank and spherical tank accidents cases. According to the results of correlation analysis, fire explosion fault tree of spherical tank system is constructed with qualitative analysis, finding out weak links and key factor which causes accidents. Dow fire and explosion index method is applied to ethylene spherical tank unit, to make fire explosion risk quantitative evaluation, determine the fire and explosion index and safety compensate coefficients, and confirm the fire explosion risk grade of the unit.Secondly based on the weak link of tank, using ANSYS software modeling the spherical tank, analyze the tank stress and displacement state in conventional load and ultimate load under, research the overall stress and displacement distribution of spherical tank, analyze the maximum stress node in various combinations limit load, obtain the specific dangerous position of the spherical tank, and extract linearization path for the dangerous parts of the fillet weld, making the stress intensity stability analysis. According to the result of calculation to predict and diagnose the most easy to cause the ethylene spherical tank location of the crack.Finally, studied the ethylene spherical tank fire and explosion accident consequence simulation calculation, getting the fire explosion hazard. Combined with fault tree analysis and the stress analysis of the specific weaknesses, determine the specific leakage source, using PHAST software analyze the consequences of spherical tank leakage diffusion in different leakage location, different diameter and different wind speed, which established a set accident consequence from the leak to spread to the chain response of vapor cloud explosion with the UDM quasi instantaneous diffusion model. And analyze the influence of thermal radiation and shock waves when spherical tank is catastrophic damaged with BLEVE fireballs. After the quantitative analysis of the ethylene leak along the wind direction, lateral direction diffusion distance and diffusion area of influence, and vapor cloud explosion radius radius of die radius, injuries and minor injuries. On the basis of analysis of accident consequences,provide the enterprise to maintain safe operation of the spherical tank and the accident emergency rescue measures and technical support.