Study On Accident Scenario Construction And Inversion Method Of Liquefied Natural Gas(LNG) Tank Farm

Storage safety of liquefied natural gas(LNG)tank farm is an important basis to ensure the continuous supply of liquefied natural gas.Once an accident occurs during the storage of LNG,not only will the supply of natural gas be insufficient or interrupted,but also will cause a lot of economic losses and even casualties.For this reason,aiming at the complex,concealed and multi-factor coupling characteristics of liquefied natural gas accident sources,this paper analyses the evolution process of LNG tank accident,aiming at the shortcomings of existing research,accurately and quickly identifies the causes and development process of the accident,so as to enhance the ability to deal with and prevent LNG tank accident risks and disasters.The main research work of this paper is as follows :(1)In view of the complex causes of LNG accidents and the interaction of mult ip le factors,and the neglect of component interaction and macro-control in existing LNG accident analysis methods,this chapter carries out safety analysis of LNG accident process from the point of view of system control combined with STAMP-STPA method.The layered rollover and fire accident scene forward model of LNG based on STAMP-STPA is established to identify unsafe control behavior and possible dangers in the model.The scene of unsafe control behavior is further analyzed,and the accident scene forward model under different conditions is established.Compared with the investigation and results of the accident itself,the cause of the accident obtained by forward model analysis is more specific,comprehensive and targeted.(2)Considering the complexity,concealment and destructiveness of lique fied natural gas(LNG)accident sources,the inversion method of constructing the topologica l network model is proposed based on the LNG fire consequence model and inversion idea,aiming at the problems of inadequacy,large amount of calculation and inaccurate location of fire sources in LNG tank area of existing inversion methods.By establishing the LNG reservoir fire accident topology network inversion model and combining with Dijkstra algorithm,the fire source nodes are inverted.Case analysis shows that the inversio n results are consistent with the simulation results,which proves the validity and accuracy of the topological network inversion method in locating the fire location.(3)Aiming at the problems of lack of causal integration and dynamic analysis in the evolution process of LNG layered rollover accidents,the inversion model of LNG tank rollover accidents is established by combining scenario model and fuzzy variable weight Petri net method.The safety state values of key elements are determined by matrix reasoning method,so as to get the cause of the accident and the propagation path.According to the scene of LNG receiving station,an accident scenario is analyzed.The results show that compared with the traditional method,the inversion method can intuitively show the influence degree of the key factors of different accident causes in the development process of LNG stratified rollover.