| Liquefied natural gas(LNG)is widely used in our country,large LNG cryogenic storage tank is liquefied natural gas,which has the advantages of less material consumption,small occupation area,small investment and convenient operation management.The current our country application of large vertical low temperature LNG storage tank is up to the northeast,there have abundant natural gas resources.Because the average winter temperatures close to minus 30 degrees,the cold weather has great influence on the transport tank.According to the current situation of the tank,the design and analysis of the tank is helpful to improve the transportation efficiency of LNG.This article made reference to many domestic and foreign literatures about large cryogenic LNG tank from the tank,the structure,design requirements,strength analysis,cold calculation and numerical simulation analysis of other aspects of the design and verification of the design of the tank.The analysis method is divided into direct and indirect two kinds of thermal stress,the direct calculation of stress angle calculation of belt,thermal deformation simulation calculation model,combined with the formula to get the final results of the angle to 4.2degrees.Through the finite element software ANSYS to design the tank for structural stress analysis,discussed in 8.6 degrees,4.2 degrees and 0 degrees angle under the influence of the strength of the strap position respectively.The strap tilt angle is 4.2 degrees,with thin film thermal stress generated by the strength is the minimum.This conclusion is consistent with the theoretical calculation results.Verifiable direct computation can replace complex software model analysis.Using the American ASME "pressure vessel specification" to set the load conditions,the design load parameters are applied to the working conditions,the finite element analysis.In this paper,the structural strength of the cryogenic storage tank under different working conditions is analyzed.The results show that the design of storage tanks in any case,the structural strength is in the safe range.Large scale vertical LNG low temperature storage tanks need to work in extremely cold areas,so the cold storage structure has high requirements.The tank wall and the bottom of the tank initiations,three parts are analyzed in this paper from the different cooling structure.In the simulation of the temperature field of the storage tank,the structure of the tank with different structure and cold storage material is analyzed.According to the results of finiteelement simulation,it is shown that there is a small gap between the structure and the conventional design in the temperature field.Leg type and the outer skirt is structure of two kinds of common boundary conditions,analysis of the advantages of both,the results showed that by this paper,leg type structure is more stable in terms of transport,strength analysis of tank has great advantages,in the premise of the same volume requirements,the conditions are better than the skirt structure outside.Through the conventional structural design and analysis of large vertical cryogenic storage tank,effect of pulling the thermal stress and the force relationship between the tilt angle and thermal stress,thermal stress range of the minimum angle,improve the economic type of tank;strength analysis of tank shows that the structure strength in different working conditions should be meet the safety conditions,the design load number should be revised according to the results of the simulation of the temperature field;tank shows that conventional thermal leakage can be conducted to choose cooling parameters.According to the analysis of two kinds of supporting structures,different working conditions have been selected.In summary,the use of software to analyze and calculate the conventional way,can help to determine the design parameters of tank,reduce the difficulty of design,to provide the corresponding help after the design of the tank. |
PDF Full Text Request