Small skid-mounted evaporation gas reliquefaction and recovery device for liquefied natural gas

Abstract

The invention provides a small skid-mounted evaporation gas reliquefaction and recovery device for liquefied natural gas. The small skid-mounted evaporation gas reliquefaction and recovery device comprises a cryogenic storage tank (1), a regenerative cryo refrigerator (3), an externally-finned condensing heat exchanger (4), a pressure testing device (5), a temperature testing device (6), a heating device (7) and a control system (8). Real-time monitoring and stepless regulation can be performed on cryogenic temperature and output cold of the cryo refrigerator according to requirements on actual pressure and heat loads inside the cryogenic storage tank, and zero consumption of an LNG (liquefied natural gas) storage tank system can be realized; pumpless circulation of gas liquid flow inside the device can be realized by relying on self differential pressure and gravity; the small skid-mounted evaporation gas reliquefaction and recovery device is low in system energy consumption, compact in structure, simple in technology process, high in reliquefaction efficiency and low in operation and maintenance costs, and skid mounting of the device can be realized.

Description

technical field [0001] The present invention relates to the technical field of reliquefaction and recovery of boil-off gas (BOG) during the storage and transportation of liquefied natural gas (LNG), and more specifically relates to a small skid-mounted BOG re-liquefaction system using a regenerative cryogenic refrigerator. Liquefaction recovery unit. Background technique [0002] Liquefied natural gas (LNG for short), the main component is methane, is recognized as the cleanest energy on earth. Colorless, odorless, non-toxic and non-corrosive, its volume is 1 / 625 of the volume of the same volume of gaseous natural gas, and the weight of liquefied natural gas is only about 45% of the same volume of water. Gaseous natural gas is compressed and cooled to its boiling point (-161.5°C) to become LNG, stored in low-temperature storage tanks, transported by special ships or tank trucks, and re-gasified when used. Compared with gaseous natural gas, due to its small size and high st...

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Problems solved by technology

[0004] After searching the existing technical literature, it was found that the "LNG Evaporated Gas Recovery and Reliquefaction Device" disclosed in the Chinese utility model patent CN202012731U uses the above-mentioned traditional reliquefaction technology, but the biggest problem of this technology is that the process of this conventional liquefaction device is complicated , too much equipment, expensive, and not suitable for the use of LNG transport tankers, small LNG storage tanks and LNG vehicle filling stations

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