Numerical Simulation And Consequence Analysis Of Continuous Leakage And Diffusion Of VOCs In Oil Storage Tanks Of Petroleum Reserve Base

In recent years,China has become a major petroleum importer in the world.Strategic petroleum reserves have become an important measure of energy security.With the emphasis on petroleum reserves,the number of petroleum reserve bases has increased year by year,resulting in a rapid increase in the number of large petroleum storage tanks and their production operations.With a large number of storage tanks operating,VOCs leakage and diffusion would inevitably occur in the actual production operation,which is related to the safety of operation in the storage tank area of the petroleum storage base.The diffusion of VOCs not only damages the environment and endangers human health,but also brings hidden dangers to the production safety of petroleum storage bases.This problem is more important.In this paper,a three-dimensional numerical model is established based on the size of the storage tank for the continuous leakage and diffusion behavior of VOCs in the storage tank.In order to explore the influence of leakage speed,wind speed,leakage port location and storage tank layout on the temporal and spatial distribution of VOCs leakage and diffusion concentration,this paper mainly adopts theoretical analysis to explore the distribution of VOCs diffusion concentration.and uses numerical simulation to obtain the temporal and spatial distribution of VOCs concentration for continuous leakage and diffusion.The main contents of this paper are as follows:Firstly,The numerical simulation verifies the accuracy and dependence of the numerical simulation method,determines the influencing factors and VOCs gas properties,analyzes the continuous leakage and diffusion behavior of VOCs in petroleum storage tanks under actual environmental conditions,describes the VOCs diffusion phenomenon by using forced convection theory and gas molecule diffusion theory,and describes the diffusion behavior after continuous leakage of VOCs according to differential equations such as mass conservation,energy conservation and momentum conservation.Secondly,on the basis of the selected numerical model,a three-dimensional numerical model is established to simulate and study the change law of VOCs concentration and velocity field in the process of leakage and diffusion under different influencing factors in real environment.By analyzing the influence of leakage speed,wind speed,leakage port location and storage tank layout on VOCs continuous diffusion,the change characteristics of VOCs leakage diffusion concentration under different influencing factors are obtained.Thirdly,based on the space-time distribution of VOCs concentration obtained from the above research,the consequence analysis is carried out,the harm to human body during the diffusion process is analyzed,and the possibility of explosion is analyzed according to the explosion limit value.The research results show that when the leakage port is in the downwind direction of the tank wall,the lower the position of the leakage port,the lower the wind speed and the greater the leakage speed,the higher the concentration value near the ground,the more serious the harm to human body,even reaching the concentration critical value of 0.02vol-for immediate death;VOCs concentration in a large area near the leakage port reaches the lower explosive limit of 0.26 vol,and the closer the concentration value is to the leakage port,the higher the possibility of explosion.This paper provides a theoretical basis for decreasing the concentration of VOCs and reducing hazards in the process of oil tank leakage,and has guiding significance to the production safety of oil reserve bases and the layout of oil storage tanks.