Simulation Of LNG Explosion Consequences In Confined Space And Design For Energy Absorption Anti-explosion Wall

With the liquefied natural gas(LNG)is widely used in the industrial production and people's life,natural gas accident is emerging gradually.Especially the explosion accident which occurred in confined space,and it could set off a chain reaction which causing heavy casualties and property losses.Therefore,it is necessary to analysis the risk of confined space and research the accident consequences for LNG receiving station,and according to the result to design an energy absorbing type anti-explosion wall,in order to reduce the damage effects of explosive shock wave on the building and equipment.These blast resistant measures can provide the support and guarantee for the development of LNG industry.The paper chooses LNG leak and explosion accident as study target,depending on the National Science and Technology Pillar Program,Chemical Industrial Park fire prevention and control technology(2011BAK03B08).Research contents are as follows:1 The leakage and diffusion simulation in LNG confined spaceThe mathematical model and physical model for the leak and diffusion of natural gas in the Confined space are constructed according to the station's specific size and the leakage parameters for pipeline pressurized gas.Gambit,a pre-processing software of Fluent,is used to draw the regulator station physical model.Fluent is used to simulate the leakage and diffusion of natural gas based on the selected gas state and discuss some factors which could influence the diffusion,including Space constraints,ventilation conditions and the state of Pressure release window.The change regulation of the diffusion and the distribution characteristics of gas cloud in respect of time and place which would provide data support for the AutoReaGas is obtained.2 The risk assessment of storage tank area of LNG receiving stationFirst of all,taking the storage tank area of LNG receiving station as a research object,the research establishes a explosion fault tree for the storage tank area to find out the elementary events and minimal cut sets that could cause combustion and explosion;calculate the structure importance of these elementary events and sort them through these numeric value.In the next place,fire & explosion index and level is obtained according to the characteristics of the tank area and LNG.Compared the result with the index which is calculated after taking various remedial measures,analyze the hazardous and harmful factors qualitatively and quantitatively and put forward the reasonable countermeasures.3 Analysis of LNG explosion consequence simulation and sensitive factors in confined spaceThe station confined space model is established by AutoReaGas software,and the initial parameters of corresponding gas leakage value are set up in the software.According to the software simulation to get the gas cloud concentration distribution and calculate gas average concentration.The result will be input to AutoRea Gas software and gas explosion is discussed in confined space.Studying spatial constraints,gas concentration value,pressure release window and window size on the distribution of gas explosion pressure.Finial,the pressure distribution and the explosion overpressure field could be obtained.4 The antiknock effect simulation and structure optimization design of energy absorbing type anti-explosion wallAccording to the explsion prone region of LNG receiving station,explosion proof wall is arranged reasonably with good antiknock effect.The explosion shock weaken effect on common type and energy absorption type explosion-proof walls can be simulated by using ANSYS/Autodyn software.Because energy material has great ability of absorbing explosion shock wave,therefore,it can be considered that the explosion-proof wall itself and material thickness as the factors of affecting explosion results.The objective is to obtain the optimal design scheme which can provides better protective function for other building and personnel.