LNG cold heat storage method and apparatus, and BOG reliquefaction method using cold storage heat and apparatus thereof

摘要

PROBLEM TO BE SOLVED: To store cold of liquefied gas an utilize the stored cold to liquefy BOG at the non-demanded time of LNG by collecting liquefied cold storing agent in a cold storing tank, and separately jetting non-liquefied remaining cryoheat storing agent into the cold storing agent in the cold storing tank so as to generate cold storing agent gas out of one part of the cryoheat storing agent. SOLUTION: Remaining cold storing agent gas 15 is separately jetted into cold storing agent 5 through a pipe 10 with many nozzles provided in a cold storing tank 3 by a carrier gas circulator 9 from the top part of a gas-liquid contact tower, and cold storing agent gas is generated. At a non-demanded time or at demanding liquefaction of BOG even at a demanded time, The BOG 18 is compressed by a compressor 17, and cooled by a BOG cooler 11 to be reliquefied BOG 19. In this case, stored cold storing agent 16 is let flow into the BOG cooler 11, and the cold storing agent heat-exchanged in the BOG cooler 11 is returned to the cold storing tank 3. At this time, by bubbling of carrier gas, the cold storing agent in the tank 3 is further cooled due to latent heat of vaporization of the cold storing agent.