The invention relates to a reliquefaction device for boil-off gas from a
liquefied natural gas vehicle gas filling
station, which belongs to the technical field of low-temperature liquefied gas storage and transportation. The reliquefaction device comprises a
storage tank of the gas filling
station, a compressor, a cooler, a
heat exchanger, a
throttle valve, a gas-liquid separator, an expansion
machine and a submerged cryogenic pump. The reliquefaction device takes
BOG which needs to be liquefied as a
refrigerant and adopts the single-stage compression and the single-stage expansion and throttling
refrigeration method, thereby leading the
BOG to achieve the
liquefaction purpose. When the pressure of a
system reaches the designed control value, the reliquefaction device is started automatically for liquefying one part of the redundant
BOG and further reducing the temperature and the pressure in the
system, when the pressure of the
system is reduced to the required value, the reliquefaction device is stopped automatically. The reliquefaction device can solve the BOG emptying problem of the LNG filling
station through reliquefaction of the BOG. The reliquefaction device can reduce the potential safety
hazard caused by BOG emptying, and have significant
social benefits and
economic benefits for protecting the environment and reducing the waste of resources.