Strength Analysis And Study Of The Reasonable Inner Supporting Structure Of LNG Cryogenic Horizontal Tank

With the development of technology,the clean energy has been more and more widely used,and the cryogenic storage equipment storing liquefied gas is increasingly needed in the industrial and civil fields.As the filling medium is possibly flammable and explosive,the storage tank is very dangerous in the case of leakage or strength failure.Therefore,the safety of cryogenic storage equipment should be ensured in engineering design.In this thesis,the strength calculation and stability analysis of a LNG cryogenic storage tank have been carried out and the reasonable inner supporting structure between inner and outer cylinder has been studied.The main work and conclusions of this study are as follows.(1)Finite element simulation of the LNG cryogenic horizontal storage tank was studied using ANSYS Workbench software.Stress distribution of the tank in five load cases in operation and transportation has been analyzed,and the maximum stress under each load case have been assessed.Results show that the supporting structure between inner and outer cylinders is unreasonable,which produces additional load and leads to the failure of some structures to meet strength design requirements.(2)The connecting strips connecting inner and outer cylinders of the LNG cryogenic horizontal storage tank was specially investigated from the strength point of view and improved strip structure was proposed based on the simulation results.It is found that the improved connecting structure is reasonable and safe under all load cases.The improved internal supporting structure is suitable for the engineering design of medium and small horizontal cryogenic storage tanks.(3)The finite element method is used to analyze the eigenvalue buckling and nonlinear buckling of the outer tank of the cryogenic horizontal tank,and the critical instability pressure of the outer tank is obtained.The results show that the tank will not collapse under external pressure.(4)The stress situation of the cryogenic storage tank with eight-point support structure is studied,and the stress distribution characteristics of the tank with eight-point support structure as the inner support mode is analyzed.The result indicates that a cryogenic storage tank with an eight-point support structure is possible to induce large local stress in the area where the inner container and the glass fiber reinforced plastic support are connected,which needs to be noted in engineering design of cryogenic storage tanks.