Fracture Failure And Consequence Analysis Of Storage Tank Structure Under Implosion Load

As the main container for storing petrochemical energy substances,storage tanks pplay a critical role inthe petrochemical industry.Storage tanks have existed for many years,and there are also quite mature systems for their design,manufacture and inspection.However,explosion accidents of storage tanks are still emerging in endlessly.How to reduce the hazards of storage tank explosions is very important.The explosion of a storage tank is generally caused by the accumulation of combustible gas from the liquid in the tank,and the vapor cloud formed by the gas is ignited by the ignition source.The high-temperature produced by the explosion of the vapor cloud will soften the structure of the storage tank and reduce the yield strength of the storage tank.Therefore,the structure of the storage tank is mostly plastic failure after the explosion of the vapor cloud of the storage tank.After the elastic failure of the storage tank,the high temperature and high-pressure explosion products in the tank leak out,and the surrounding things will be damaged by thermal radiation and explosive shock waves.Therefore,this paper will study the dynamic process of the tank structure fracture after the explosion of the vapor cloud of the tank,and calculate and analyze the dynamic response of the explosion product ejected from the explosion source tank to the adjacent bank.(1)Calculation of implosion load of storage tank based on multi-load actionAccording to the temperature load and pressure load caused by the explosion of the vapor cloud of the storage tank,a finite element model of the fluid domain in the 3000m~3vaulted storage tank was established,and the explosion temperature and pressure explosion load of the vapor cloud were calculated based on the TNT equivalent method and the CFD computational fluid dynamics method.Calculation.The calculation results show that the temperature after the explosion will stabilize in fluctuations,and the temperature near the storage tank will stabilize at about 3000k when exposed to the flame at last,while the explosion pressure will change with the change of working conditions,and the detonation point is away from the tank wall 5m,the pressure near the explosion point is 1.2MPa,and when the distance becomes 1m,the monitored pressure increases by 3 times.An increase in the liquid level will increase the explosion pressure by up to 150%,and an increase in volume will increase the pressure value by up to 250%.(2)Fracture and expansion analysis of storage tank structure under implosion loadIn order to simulate the fracture expansion of the storage tank structure truly and accurately,this paper simplifies the storage tank while retaining the characteristics of the side angle steel and the variable wall thickness of the storage tank,and uses the shell element to establish the three-dimensional finite element model of the storage tank.The temperature field calculated in Chapter 2 is applicable to the structure as a load,and the vapor cloud is equivalent to TNT for multi-condition storage tank implosion calculation.The calculation results show that when TNT is 1m away from the tank wall,the tank will be directly from a breach at the tank wall,and the fracture location for other conditions is at the top wall connection near the explosion point.After the explosion of the storage tank,the storage tank containing more than half of the liquid basically does not lift off,and the maximum lift of the amount under this calculation condition is 323mm.(3)Explosion load expansion analysis based on multi-media fluid load transferThe finite element calculation model of the inner and outer fluid domains of the storage tank is set up.The inner and outer fluid domains realize the load transfer by setting the explosive break position as the inner surface.The position of the breach is formed based on the absolute size of the breach calculated in Chapter 3 and converted into a rectangular breach of equal area.After calculation and analysis,it is obtained that the size of the explosion radiation area is proportional to the volume of the storage tank and the size of the breach,and inversely proportional to the height of the liquid level,and has little relationship with the position of the initiation point.(4)Analysis of the consequences of the impact of the implosion of the storage tank on the adjacent storage tankDetermine fire distance between storage tanks according to the oil depot design specifications and establish a numerical calculation model for multiple storage tanks.The temperature field data of the outer fluid domain calculated in Chapter 4 are applied as a load to the outer wall of the adjacent storage tank.The explosion source storage tank is simplified as a rigid body to analyze the dynamic response of the adjacent storage tank under the implosion load of the storage tank.It is possible to conclude that the explosion of a storage tank under any working condition will cause damage to the adjacent storage tank.Increasing the distance between storage tanks can effectively reduce the severity of damage to neighboring storage tanks after a storage tank explosion.This paper calculates the dynamic fracture of the storage tank structure under implosion load under different working conditions,and analyzes the explosion radiation area and the damage factors of adjacent storage tanks,and puts forward two suggestions:One is to regularly check the flammable gas volatilization.,take steps to discharge combustible gas.For highly volatile refined oil or use floating roof storage tanks for storage.The second is to improve the installation distance of storage tanks.This method can effectively reduce the damage caused to nearby storage tanks after the explosion,and avoid the occurrence of chain explosion accidents.