Research On Digital Emergency Response Plan Of LNG Storage Tank Based On Numerical Simulation

Liquefied natural gas(LNG)is favored in the energy systems of various countries due to the advantages of high storage efficiency,high calorific value and environmental protection.The accidents of LNG storage tank are caused by complex,hidden sources and strong coupling of multiple risk factors.As a key facility for storing LNG,Once the leakage occurs,it is very easy to cause fire,explosion and other catastrophic accidents,which will pose a great threat to the surrounding personnel,equipment and environment.In this thesis,an LNG receiving station in Jiangsu Province has been studied as a research object,and accidents scene are constructed.FLACS software was used to simulate the consequences of LNG tank failure.Based on the simulation results,the corresponding emergency response plan is prepared.Combined with the general idea of digital plan development,a new digital emergency response plan for LNG storage tank is proposed.The main work of this thesis is as follows:(1)The location,natural conditions and surrounding environment of the LNG terminal has been investigated.In addition,the leakage models,heavy gas diffusion process and hazard consequences of leaking were analyzed.Event tree analysis(ETA)was used to analyze the influence of leakage time and ignition timing on potential fire and explosion accident modes.(2)A statistical analysis was made of 246 historical accidents in LNG receiving stations and peak-regulating stations between 1965 and 2000 to summarize the LNG storage tank accident type.Besides,statistics and analysis were made on 14 typical LNG storage tank accidents at home and abroad.Based on the accident analysis,the LNG storage tank accident scenario was constructed.(3)The accident scene was simulated and analyzed by using FLACS software.The results show that liquid pool area is 5170 m~2 and the maximum width is 130m in 300s after leakage.The low temperature dangerous area(T?-20?)is positively related to liquid pool area,and the maximum width is 134m.There is an explosive gas mixture formed by the leakage,and maximum concentration range can spread to 313m.The oxygen concentration is negative correlated with the vapor cloud concentration,and the farthest distance of asphyxiating injury to human body is 233m.The range of thermal radiation damage caused by the steam cloud fire can reach to 18m at vertical height,and the farthest influence distance is 121m.The maximum overpressure generated by explosion is 12.5k Pa,causing slight damage to the operators and buildings around the production area.(4)The theory and technology system involved in preparation of digital emergency plan were systematically described,and the general idea of digital plan development was summarized.In the present study,according to the results of numerical simulation and characteristics of the LNG terminal,a digital emergency plan for LNG storage tank was proposed.