The structure of the LNG ambient air vaporizer is relatively simple, mainly composed of star-shaped finned tubes. Its structural design is mainly reflected in the calculation of basic parameters such as the diameter of the finned tube, the number of fins, and the length of the finned tube. These are obtained through Finned tube heat transfer is determined. The design method includes thermodynamic calculation, and it is proposed that the selection of the length of the air duct is generally determined by the requirement of the heat exchange area margin of the vaporizer.
Factors such as design margin, structural form, finned tube heat transfer calculation, operating conditions and time, temperature difference compensation measures, and gasifier use should be fully considered during structural design. The operation stability of the LNG ambient air vaporizer is more important. Since frost will continue to form during operation, which will affect the heat transfer efficiency, it must be defrosted regularly. At present, the operation generally takes 8 hours as a shift, so the maximum gasification retention time is required to be no less than 8 hours. During operation, the temperature changes greatly, and cold cracks are easy to occur. It is required to have measures to eliminate the influence of temperature stress in the structural design.
Air-temperature LNG vaporizers can be divided into pressurized type and air-supplied type according to the application. The structures of the two are basically the same, with only slight differences. Mainly, the pressurized air temperature vaporizer only has an evaporation part, while the air supply type air temperature equipment includes an evaporation part and a heating part.
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