Numerical Simulation Study On The Disaster Effects Of Leakage, Diffusion And Explosion In Large-scale LNG Receiving Stations

With the rapid development of the natural gas industry,the safety of liquid LNG in the process of filling,transportation and storage has attracted great attention.As a storage module in the LNG industry chain,the safety of LNG receiving station is even more important.Due to the functional characteristics of LNG receiving stations(large quantities of low-temperature LNG are stored),leakage accidents at receiving stations often cause unbearable consequences.Therefore,the analysis and study of the gas cloud diffusion after leakage accidents at LNG receiving stations and the damage range after accidental ignition and explosion will have important scientific guiding value for the future construction of the geographical location of LNG receiving stations,the protection design of safety facilities in the stations and the formulation of emergency rescue plans for enterprises.Based on the literature of researchers at home and abroad,the basic characteristics of LNG gas cloud diffusion and explosion are known,and the numerical calculation model of LNG leakage is established.The accuracy of the FLACS numerical calculation model established in this paper is verified by the experimental data of Falcon series diffusion field tests and the international standard for evaluating LNG heavy gas diffusion.Based on the field investigation of a large LNG receiving station in China,the two major hazard sources in LNG receiving station are analyzed,i.e.liquid filling area and storage tank area,and then the two areas are simulated and the calculation results are analyzed,and the diffusion law of LNG gas cloud is obtained:after LNG leakage and gasification in liquid filling area,a low and flat gas cloud is formed under the interaction of wind field and buildings in the station;The LNG gas cloud in the storage tank area forms a thick and thick gas cloud cluster under the interaction of the wind field and the tank farm cofferdam.In order to comprehensively study the leakage hazards of large LNG receiving stations,this paper establishes different analysis models by changing the key factors such as wind direction,wind speed and the height of storage tank cofferdam,and obtains the potential explosion hazards caused by LNG gas cloud diffusion under the influence of different factors and the impact range of suffocation hazards.Explosion is the follow-up process of leakage.In this paper,the leakage gas cloud in the storage tank area is studied under the benchmark working condition model.Ignition and explosion experiments are carried out at different positions in the initial,middle and final stages of gas cloud diffusion,and the overpressure damage range after explosion is divided.On the basis of Baker’s model,the dangerous area of fireball heat radiation is divided.The mass of gas cloud ignited is greater,the maximum radius of thermal damage radiation is larger.The maximum death radius is 178 m,and the ignition heat radiation range of the storage tank area basically covers the whole station,and only after accidental ignition is 450 m away from the leakage source can personnel be basically protected from injury.