Seismic Reduction By Anti-sloshing Analysis On Large-scale AC-LNG Storage Tanks

LNG is gradually becoming a significant energy source in the world,and with the world currently looking for cleaner and more environmentally friendly fuel sources,LNG plays a vitally important role.With this much said,the storage of LNG therefore becomes a vital necessity and thereby creating a need for:Bigger and more economically designed LNG tanksSafer,stable and stronger LNG tanks as more and more tanks are built in high-intensity seismic regions.To achieve both objectives mentioned above: firstly,research on All Concrete LNG(AC-LNG)tanks in which has not been much research is being done,this is not only done to reduce the cost of the currently popular traditional LNG tanks,which have an inner tank made of 9% nickel-steel and are quite expensive and have complex construction problems but also helps diversify the LNG tank designs and benefits relative research about similar cryogenic storage tanks(liquid oxygen and liquid nitrogen).Secondly,seismic design and response research of the AC-LNG such as dynamic response,anti-sloshing and vibration is carried out and compared to the traditional LNG tanks to show its integrity and advantages.In this paper,based on a practical engineering project and the use of ADINA and ANSYS finite element analysis software,a study of the AC-LNG storage tanks dynamic characteristics,seismic responses and seismic reduction by anti-sloshing using a new method called “Lotus Leaf method”(an anti-slosh floating blanket)is carefully analyzed and researched.The main research focus is as follows:1.Using engineering design data from an existing LNG storage tank,a parallel design of the inner tank is made.Then on this design base two kinds of Three dimensional finite element models(With stiffening rings and with both stiffening rings and Lotus Leaf(LLM))were created using ANSYS.At the same time,the liquid model was established and liquid-solid coupling effect considered.2.The dynamic characteristics,including the inner-tank's basic vibration model of liquid-solid coupling and sloshing as well as the outer-tank's basic vibration model were studied and the effect on an empty,half-full and full tank were compared.3.Time history analysis of AC-LNG tank under four types of ground are carried out to obtain the structure's seismic response under different site conditions using acceleration vibration input method.Based on this,some important indexes were obtained and analyzed,such as acceleration and displacement envelope curve along height direction,the stress distribution,and the base shear,overturning moment,the sloshing wave height and hydrodynamic pressure.4.Dynamic responses for AC-LNG was disserted and compared to former analysis of the traditional 9% nickel-steel tank and Data was recorded.