| The road transportation accidents of tank truck for hazardous chemicals occur frequently and are highly dangerous.So the effective prevention and control of hazardous chemical transportation accidents is of great significance and practical urgency to the safety of China’s transportation.Because of the particularity of accidents and their consequences,it is impossible to simulate possible accidents with huge losses of property and casualties.The study of accident simulation theory and method based on scenario construction is an important approach for accident prevention and control.Based on the accident data and scenario construction theory of national tank vehicle road transportation of hazardous chemicals in 2013-2018,this paper focuses on the screening of accident scenarios,the construction of regional scenarios,the simulation of accident scenario evolution and consequence response,and analyzes with the aid of FLACS software to predict the scope of accident impact and the severity of the hazard under different circumstances.This study has an important meaning on the relevant design and planning of enterprises,emergency response to accidents,self rescue of the public,etc.It’s main research contents and results are as follows:1.This paper selected the credible worst-case scenario.This paper explored the characteristics and rules of accidents caused by road transportation of hazardous chemicals with tank trucks from 2013 to 2018 in China from the aspects of casualties,occurrence time,region,category,cause and time of emergency rescue,and studied the present situation and influencing factors of time-consuming emergency rescue in China.The study determined that the accident occurred at an intersection of Huanghe Road,Dongying City,Shandong Province.The reason for the accident was that the 150 mm top safety valve of LPG tank truck was completely loosened due to its rolloff,and caused the leakage.It summarizes the occurrence,consequences and causes of four LPG tank truck accidents at home and abroad,and screened out the dynamic evolution scenarios of LPG tank trucks from leakage to gas cloud diffusion to gas cloud explosion.2.This paper studied numerical simulation and consequence analysis of leakage and gas cloud diffusion processes.In the numerical calculation of leakage and diffusion process,five working conditions were studied and analyzed.The results show that the diffusion process of LPG cloud shows the characteristics of gravity settlement,when LPG gas cloud is affected by wind and current,buildings,sharp corners and corners of buildings,there will be acceleration,deceleration or separation of LPG cloud.According to the results of leakage and diffusion,the scope of poisoning,suffocation and explosion can be determined.3.Numerical simulation and consequence analysis of explosion process are carried out.Using the method of equivalent gas cloud to convert the calculation results of leakage and diffusion that mass flow is 29.1 kg/s.According to the guideline for quantitative risk assessment of chemical enterprises(AQ / T 3046),the influence of overpressure on main objectives is quantified.Under this condition,the result of explosion is "extensive injury" to people and buildings.In terms of "concentrated injury",buildings within 110 square meters are affected.According to the results of explosion numerical calculation,the maximum disaster distance caused by explosion accident can be calculated.Secondly,the degree of congestion can stimulate the overpressure caused by explosion.4.First of all,according to the law of LPG leakage and diffusion,measures and suggestions are put forward from the aspects of monitoring the concentration of gas cloud,elimination of fire source,protection of personnel,weakening the volatilization of LPG,evacuation of people,collection or transfer of LPG,etc. |
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