Safety Analysis And Numerical Simulation Of Leakage Accident In LNG Supply Station

With the increasing demand for clean energy in the world,the natural gas industry has developed rapidly.As a safe,efficient and convenient energy,liquefied natural gas(LNG)is a good choice for transportation and storage in the energy industry,and its proportion is also growing.With the growing concern for the safety of production in China,LNG standardization work has also been put on the agenda.Urban LNG supply station,as an important part of the natural gas industry,is common in personnel-intensive areas,so its safety should be taken seriously,relevant specifications are also at the planning stage.Against this background,we analyzed the safety of LNG supply station,researched the safety distance based on the consequences of leakage accident.By reading a lot of literature and combined with engineering examples,analyzed the leakage accidents that may occur in a LNG supply station,established three types of accidents-LNG pool fire,LNG leak diffusion and LNG vapor cloud explosion as our study object.According to these three kinds of accidents,detailed analyzed its mechanism and accident evaluation criteria,selected appropriate numerical models,and calculated the results of engineering examples,compared the results with evaluation criteria,so as to obtain the numerical results of the safety distance under three kinds of accidents.In LNG poor fire research,we analyzed the mechanism of it,and calculated three empirical models-point source model,Mudan model and Shokri Beyler model.he main conclusions are as follows: The safety distance of a fire accident should be based on the radius of the pool as the main standard,rather than the storage of tank in previous standard;In consideration of safety and model accuracy,the safety distance should be calculated by using the Mudan model;Taking the 5m radius liquid pool as an example,the calculated safety distance is 14.5m,23 m and 27 m respectively according to the equipment,public buildings and personnel.In the study of LNG leak diffusion accident,used FLUENT as the tool,innovative adopted DPM model to make the simulation more closer to real physical process and the data is more accurate.Taking 2000m3 storage tank as an example,the numerical simulation is carried out within 20 s.Result shows: Process simulation is high,the data results are accurate and able to describe the whole process at a high reduction degree;The whole process can be divided into three stages-the initial stage,the shock stage and the stable development stage.The maximum distance of the vapor cloud is 80 m and the flammable gas cloud(concentration is more than 2.5%)is 51 m.In the study of LNG vapor explosion,the TNT equivalent model is used as the numerical simulation tool to analyze the possible harm radius of the accident in the most unfavorable situation.Obtained the radius of death,serious injuries,minor injuries and property loss under different tank storage LNG vapor explosion,as shown in Figure 4-3.