Numerical Analysis Of Seismic Response And Cryogenic Effect Of Ultra-large Lng Storage Tank’s Outer Tank

LNG storage tanks are important facilities for the storage and consumption of natural gas. Due to the urgent need for energy and favorable state policies, more and more LNG storage tanks will be designed and built, and the capacity of LNG storage tanks will become higher. Cryogenic effect or earthquake may cause the tank to rupture, leading to the leakage of ultra-low temperature liquid. Once the leakage of liquid occurs, the consequences will be disastrous. At present, the capacity of LNG storage tanks which have been studied around the world is no more than 160 000m3. 200 000 m3 LNG storage tanks are rarely studied. While analyze the seismic response of LNG storage tanks, most of the previous studies have used the time-history method and ignored the interaction between inner and outer tanks.The main research contents were as follows:Part 1: Considering the influence of the steel and ring beam, the refined model of LNG storage tank was built and its reliability was verified.Part 2: The cryogenic effect on the outer tank of LNG storage tank was analyzed, and the effect of temperature on the outer tank of LNG storage tank was defined.Part 3: Considering the interaction of inner and outer tank, the dynamic response of outer tank was analyzed by using mode decomposition response spectrum method and time-history analysis method respectively, and the results calculated by the two methods were compared.Part 4: The seismic response of outer tank with isolation was analyzed, and the influence of the base isolation on the seismic response of outer tank was defined.Through analyzing the results,we find that: A large value of the first principal stress of outer tank is located at the height of the leakage liquid level and the bottom of outer tank under leakage condition;The maximum value of the first principal stress of outer tank is more than the tensile strength of the concrete in the connection of outer tank under earthquake; Without taking into account the peripheral seal, the vibration amplitude and the vibration period of the ceiling of the LNG storage tank is larger than that of the dome under earthquake; When considering the influence of inner tank, the seismic response of outer tank is slightly reduced; The isolation device can reduce the seismic response of LNG storage tanks effectively.