Low temperature storage tank acoustic emission detection technology and problems in operation

{1} The application of acoustic emission technology in the structural integrity detection and evaluation of LNG storage tanks can be divided into three aspects: acoustic emission detection and evaluation of newly made low-temperature storage tanks, acoustic emission detection and evaluation of in use LNG storage tanks, and online monitoring and evaluation of acoustic emission of LNG storage tanks. LNG storage tanks are prone to crack formation under the influence of medium temperature and pressure. During the process of crack formation and propagation until cracking, acoustic emission energy signals of different sizes are emitted. Based on the magnitude of these energy signals, the occurrence and extent of crack propagation can be determined. An important feature of acoustic emission testing is the loading of LNG storage tanks during testing. The commonly used loading method is to conduct a pressure test on the LNG storage tank, and sometimes the working medium is directly loaded. If there is an acoustic emission localization source signal generated at the defect site during the entire loading process, the defect is judged to be active; otherwise, the defect is judged to be inactive. The advantage of acoustic emission detection is that it can detect active defects, such as material fracture and crack propagation, providing a basis for usability evaluation; Can be operated remotely, allowing for long-term monitoring of equipment's allowable status and defect expansion; The device is relatively lightweight; Its limitation is that the equipment is expensive; High quality requirements for operators; There are many interfering factors during the detection process; After the acoustic emission testing is completed, ultrasonic testing is generally required for retesting. {2} When selecting the location of liquefied natural growth gas storage tanks, the specific location of the natural growth gas pipeline should be taken into account to meet the load range that the pressure can withstand, while maintaining a relative distance from surrounding residential areas to prevent explosions and other hazards caused by natural growth gas pipeline leaks that will not affect urban residents. Try to locate LNG gasification stations in the outer ring of the city as much as possible, providing important protection for improving the efficiency of liquefied natural growth gas transportation. At the same time, combined with the design of urban environment, the selection of LNG gasification station is coordinated with the surrounding environment, laying the foundation for the promotion of modernization construction in the design of gasification station based on modernization. When selecting the site for a gasification station, geological conditions should also not be ignored. It is advisable to choose a relatively flat site as much as possible to facilitate the transportation of liquefied natural growth gas. At the same time, combined with the required environmental carrying capacity, the construction cost of the gasification station can be reduced and the overall work efficiency can be improved. 2. The problems in the civil engineering sub items should be considered as much as possible in the design of the gasification station, and the selection of corresponding locations should be taken into account. The design of selecting a suitable location for the gasification station should start from the perspective of fire prevention (mainly based on actual reports), combined with the specifications and standards of gasification station design, and carry out good design and construction control on the basis of protecting the stable operation of the gasification station. In addition, the design of the gasification station is based on the selection of production areas, taking into account the requirements for natural growth gas, to provide corresponding quantities. In the design of civil phase separation engineering, relevant personnel should be able to clearly recognize that civil engineering work occupies a very important proportion in LNG gasification stations. Combined with the corresponding drainage design of the site, the selection should be based on the terrain conditions. The structure of the site should be arranged on the basis of pipeline design to meet the requirements of design work and provide important protection for the design. If the design and debugging are to be carried out again, the drainage of the slope should be designed, and the height of the pipeline in the storage tank area should be maintained within the normal range to prevent any impact on the pipeline structure during drainage. 3. When conducting process compensation design for the problems existing in the process sub projects, the pipeline design issues should be considered and reasonably labeled. If there are loopholes between pipeline valves, it can easily affect the operation of pipelines and related equipment. Some staff need to analyze the actual situation and combine it with the design arrangement of the gasification area pipeline to carry out corresponding processing. If there are significant differences between the pipeline design and the overall design specifications, the relevant steps of the operation should be reduced and the process design planning of the gasification area should be re planned. If there is a certain distance between the valve gate and the pipeline, it should be treated according to the standard of pipeline elevation design, otherwise it will bring burden to the use of the pipeline and other related equipment. In addition, appropriate fire protection design should be carried out. In some areas where the winter is relatively cold, the pipeline network is susceptible to temperature changes, and the bearing capacity of the foundation compression should also be included in the design arrangement of fire protection pipelines.