The Security Of Large Scale Low Temperature Liquefied Nature Gas Tank Numerical Analysis

LNG receiving terminal take the important position in the entire LNG production chain, as the LNG storage tank is important storage facility in the receiving station, which design and construction are quite complex, and the technology also requests to be strict. Its secure not only influence liquefied natural gas receiving station’s receiving and transmission but also influence its investment and economy. Its secure research is very necessary because accident consequence of the LNG storage tank is inconceivable. This article main study16×104m3LNG tank, and uses the finite element numerical simulation technology to carry on the analysis to the storage tank. This article main research content is as follows:Under the hydraulic pressure test condition, it obtains this storage tank stress intensity distribution regularly through the finite element analysis, and found that the greatest stress intensity value appears in big angular weld place of connection between the shell of tank and the tank bottom, and the greatest circular stress appears in connection point of the first and the second shell of tank., The tank bottom stress stiffness is very small because the material of tank bottom is the rigid restraint.By the finite element analysis of LNG tanks, we can draw following conclusions:the maximum deformation of tank in low-temperature conditions is the top, the maximum thermal stress intensity values of tank appear in the lateral surface of tank bottom chime and the maximum annular thermal stress appear in the bottom of tank skin. By means of stress linearization, we discovered that the thermal stress value of dangerous sections such as big fillet weld is larger than the allowable stress value of material, for locality and limiting there respond to larger thermal stress.LNG storage tank heat leakage will cause the roll-over in it, which will cause the overpressure accident. The check computation of the storage thermal insulation is done in this paper. The result shows that the tank has a good heat-insulating property. Through analysis of the tank thermal insulation structure, the structure complexity of the tank bottom and tank wall joint (TCP) is found out. So the temperature field analysis about the TCP structure by using finite element analysis through ANSYS software is done. Through the temperature distribution map, it shows that the heat-insulating property of the tank wall and bottom is very reliable and the temperature gradient of TCP structure is relatively large. So the joint structure design must meet the tank structure requirements, meanwhile how to avoid the formation of thermal bridge, which will cause larger heat loss, must be considered too.