Management Technology And Application Of LNG Storage Tank Structural Integrity

With the adjustment of the country’s energy structure and the improvement of people’s awareness of environmental protection,LNG has gradually expanded its share of energy demand with its clean and efficient advantages.So,the investment and construction of LNG storage tanks has increased.Due to the large amount of low-temperature,flammable,and explosive liquids stored in the storage tanks,accidents in the LNG storage tanks will cause serious losses,and comprehensive monitoring of the storage tanks has become a necessary requirement.Although researchers and operators have wealth experience in the operation and maintenance of LNG receiving stations,there is no overall grasp of the structural integrity issues during the operation of LNG storage tanks.With the rapid development of informatization,digitization,intelligentization and LNG storage tank technology,the structural integrity technology of LNG storage tanks has been with higher demand.The research contents are as follows:(1)Construction of LNG storage tank digital structure model and research on mechanical propertiesThe digital modeling method of LNG storage tank structure is developed.The inner tank,insulation layer,outer tank,base,etc.of LNG storage tank models are established,and the detailed modeling and division method of complex areas is studied emphatically.A digital modeling process for LNG storage tanks is developed to achieve rapid and accurate modeling of LNG full-capacity storage tanks.Pre-cooling,unloading,and full load working conditions are carried out based on the built storage tank model and sensor information during the operation of the storage tank.The temperature distribution and strength of the storage tank under ultra-low temperature conditions and its structural weaknesses are analyzed to provide data support for the daily operation,management and maintenance of the storage tank.(2)Research on life prediction method of LNG storage tankA comprehensive method for predicting the remaining life of LNG inner tanks is proposed,combined with the constructed physical model of the storage tank and crack data to achieve accurate prediction of the life of the storage tank.By considering material uncertainties and model uncertainties,using Bayesian inference method combined with the collected storage tank crack data,the uncertain factors are updated to complete the construction and update of the inner tank crack model.The constructed model is simulated and verified with MATLAB.(3)Research on LNG storage tank structural integrity management systemCombined with the concept of digital twins,a framework for structural integrity management of LNG storage tanks is proposed based on the previous research.The risk assessment and consequence identification and risk analysis of LNG storage tanks is carried out based on the risk assessment theory.LNG storage tank structural integrity database is constructed and LNG storage tank structural integrity management system is developed based on VB6.0.The main functions include storage tank parameter setting,storage tank thermometer pressure monitoring,life calculation,risk assessment,storage tank maintenance management and managing the structural integrity of LNG storage tanks.