Study On The Method Of Accident Risk Assessment Of Lightning-Stroke On Storage Tanks

Most of the chemical industry parks in China are located in open areas or coastal areas where lightning activity is frequent,making the possibility of lightning strikes on storage tanks greatly increase.However,there are few studies on the quantitative risk assessment of lightning strike tank accidents,and no systematic assessment process has been formed.This paper takes the lightning strike tank accidents as the research object.Through the analysis of the causes and frequency of lightning strike tank accidents and the consequences of the accidents,the risk assessment method for lightning strike tank accidents is studied.The main research contents are as follows:The mechanisms of action of lightning on the storage tank and its harm forms have been analyzed,meanwhile,through the accident tree the causes of the lightning tank accidents have been analyzed.The accident scenarios that might happen have been identified and their evolution form has been analyzed.Through Monte Carlo Simulation,based on the Electrical Geometry Model,the forecast model of tank lightning probability has been established,and influence of different structural parameters and layout parameters of the storage tank on the tank lightning probability and shielding effect and sensitivity have been analyzed.The frequency of lightning strike has been calculated through the probability of lightning strike,and the influence of the selection of area on the frequency and probability of lightning strike have been analyzed.Based on the probability model,a more accurate calculation method of the position factor in IEC lightning frequency calculation formula is proposed.The consequences and frequency of lightning accidents of different types of storage tanks under protective devices have been analyzed through accident trees.Taking the Ningbo chemical industrial park as an example,the probability,frequency of lightning strikes and the frequency of different accident scenarios of different types and specific layouts of storage tanks have been calculated.The accident risk and potential property loss of lightning strike tanks have been quantified,providing the theoretical basis for risk assessment of lightning accidents in large tank farms and more targeted lightning protection.The study shows that the height of the tank has greater impact on the probability of lightning than the diameter of the tank.As the distance between the tanks increases,the probability of a lightning strike on the tank increases.Compared with the inside tank of the same specification,the probability of a lightning strike on the outside tank is greater.