Overview of Non destructive Testing Technology for Low Temperature Storage Tanks and Outer Tank Design

&Overview of Non destructive Testing Technology for LNG Storage Tanks Generally speaking, a sealed equipment that contains gas or liquid and carries a determined pressure is a pressure vessel. Pressure vessels, due to the enclosed pressure of gases or liquids inside or outside, are prone to accidents such as explosions, fires, and environmental pollution. Therefore, the production and testing of pressure vessels have high requirements for safety. Non destructive testing technology plays a significant role in protecting equipment in pressure vessel manufacturing, including visual inspection (VT), ultrasonic testing (UT), acoustic emission testing (AE), radiographic testing (RT), magnetic particle testing (MT), penetrant testing (PT), eddy current testing (ET), magnetic leakage testing (LT), and magnetic memory testing. Non destructive testing of LNG storage tanks is a comprehensive application technology, and in-depth research on non-destructive testing technology will promote the healthy development of this industry. The role of LNG storage tanks in economic development is becoming increasingly prominent. It can be foreseen that LNG storage tanks will achieve considerable development, with larger volumes and higher parameters. The use of materials, structures, media, etc. will become more complex, and corresponding detection technologies for LNG storage tanks will continue to be updated. With the development of non-destructive testing technology and the accumulation of experience, new testing techniques and ideas are constantly emerging, which promotes the continuous development of non-destructive testing technology. The new non-destructive testing technology has gone through a transformation process from non-destructive testing (NDI) to non-destructive testing (NDT) and then to non-destructive evaluation (NDE), and is developing towards automatic non-destructive evaluation (ANDE) and quantitative non-destructive evaluation (QNDE). The implementation of healthy, comprehensive, and big data processing based testing is constantly breaking through the technological barrier, and green non-destructive testing, which is characterized by digital images and informatization, is also greatly inspiring the revitalization of the industry. I believe that in the near future, non-destructive testing technologies in industries such as nanomaterials and microelectromechanical devices, which are at the forefront of technology, will be rapidly developed. &The design standard for the outer tank of liquefied natural growth gas storage tanks is API620. The outer tank of a single capacity tank only accommodates cold insulation materials and evaporated gases, and does not require the loading of low-temperature liquids. Therefore, the design requirements of the outer tank are similar to those of a regular room temperature storage tank. 1、 The low soil temperature, soil freezing, formation of ice layer in the soil (mainly for drilling soil), and thickening of the ice layer at the lower part of the LNG storage tank foundation can cause huge expansion forces. The lifting force generated by these expansion forces can harm the storage tank and its components, such as the storage tank with the pump suction port connected to the bottom of the tank. To prevent such hazards, the foundation of the storage tank generally adopts a foundation with a heating system or an elevated concrete pedestal. Due to the small total weight of the 20000m ³ low-temperature storage tank, the foundation of the natural growth gas storage tank adopts an elevated concrete pedestal, which is convenient for production operation and maintenance, and saves construction investment. 2、 The design of the outer tank should consider various aspects including construction, testing, replacement pre cooling, normal operation, and maintenance. The main external loads include: (1) internal pressure and vacuum partial pressure caused by operation; (2) The weight of the storage tank body and specified medium from an empty tank to a tank filled with high gas pressure; (3) Partial and complete support systems, as well as anticipated impacts from foundational conditions; (4) Additional loads generated by platform and ladder supports, as well as climate conditions such as excessive snow; (5) Wind load or specified seismic load; (6) Load caused by pipeline connection; (7) The weight of all insulation materials.