The Security Study Of Railway LPG Tanker Transportation

With the rapid development of Chinese industry,Liquefied Petroleum Gas(LPG) was widely used in different areas, the safe transport of LPG has become a kind of market demand,and it is indispensable.In recent years,the railway traffic volume is going up,at the same time,the security incidents have shown a trend of high incidence,this will cause some damage of people’s life and economic production.It can provide a theoretical basis for finding out the key security risks of accident,and establishing the disaster emergency plan through the study of LPG railway tanker safety.In this paper,the main research contents include some aspects as follows:Firstly,This paper summarizes the achievements and contents of the security study of railway LPG tanker transportation at home and abroad,there are some typical accidents of railway LPG in recent years,we get the main accident types are tanker medium leakage,fire and explosion.We analyze the safety influencing factors which lead to the railway LPG tanker accident by using the FTA method,and calculate the structure importance of each factor,then the temperature and the filling quantity are studied as the main influencing factors.Secondly,based on the front theory,it established the physical model and mathematical model when the LPG tank was in the high temperature environment,then describing all kinds of the heat transfer process,fluid flow,and the changes between phase and liquid in the tank with the heat transfer model,turbulence and multiply-phase flow model,the boundary conditions are convection between the inner surface and medium,medium between external wall and surrounding.Thirdly,the temperature field and flow field in the LPG tank that is in a high temperature environment have a two dimensional numerical simulation by using ANSYS software,when loading the boundary conditions it changed the initial environment of high temperature and filling volume,the results of numerical simulation were analyzed,obtaining the varying pattern of the pressure in tank and temperature of tank wall when the filling weight and initial temperature are different,and then put forward the suggestions on the security of LPG transport.The simulated results show that,the liquid phase and gas phase have the obvious thermal stratification in tank,and the temperature of gas phase is higher than the temperature of liquid,the highest temperature of tank wall is in the gas.The temperature of tank wall and medium increases with the raising of initial temperature,temperature of the medium comes to the super-heat limit of LPG in more and more short period of time,the tank is more and more dangerous.Medium in the tank expanded greatly with the increasing of temperature,the pressure increases with it,the temperature and pressure are maximum when the initialtemperature is 500 degrees,on the contrary,the temperature and pressure are minimum when the initial temperature is 100 degrees.The change rate of medium temperature decreases with the increasing of filling weight,the change rate of temperature is minimum when the filling ratio is 90 percent,the change rate of temperature is maximum when the filling ratio is 50 percent.The rate of pressure rise increases with the rising of the filling weight,the rate of pressure rise is maximum when the filling ratio is 90 percent,on the contrary,the rate of pressure rise is minimum when the filling ratio is 50 percent.