Ship

Patent metadata

Field	Value
Publication number	US-11136104-B2
Application number	US-201616090077-A
Country	US
Kind code	B2
Filing date	Oct 21, 2016
Priority date	Mar 31, 2016
Publication date	Oct 5, 2021
Grant date	Oct 5, 2021

Abstract

A ship comprises: a tank; a multistage compressor for compressing a boil-off gas discharged from a storage tank and comprising a plurality of compression cylinders; a first heat exchanger for heat exchanging a fluid, which has been compressed by the multistage compressor, with the boil-off gas discharged from the storage tank and thus cooling the same; a first decompressing device for expanding a flow (“flow a1”) partially branched from the flow (“flow a”) that has been cooled by the first heat exchanger; a third heat exchanger for heat exchanging, by “flow a1” which has been expanded by the first decompressing device as a refrigerant, the remaining flow (“flow a2”) of “flow a” after excluding “flow a1” that has been branched and thus cooling the same; and a second decompressing device for expanding “flow a2” which has been cooled by the third heat exchanger.

First claim

The invention claimed is:

1. A boil-off gas reliquefaction method used in a ship having a liquefied gas storage tank containing liquefied gas with a boiling point of higher than −110° C. at 1 atm, the boil-off gas reliquefaction method comprising:
compressing boil-off gas, by a multi-stage compressor, discharged from the storage tank;
cooling and liquefying, by a first heat exchanger, at least a portion of the compressed boil-off gas, and supercooling, by a second heat exchanger, the liquefied portion of the compressed boil-off gas through a heat exchange process using the boil-off gas discharged from the storage tank as a refrigerant;
dividing the fluid supercooled by the second heat exchanger into at least two flows comprising a first flow and a second flow;
expanding, by a first decompressor, the first flow and using the expanded first flow as a refrigerant in a third heat exchanger;
cooling, by the third heat exchanger, the second flow; and
expanding and reliquefying, by a second decompressor, the second flow cooled by the third heat exchanger,
wherein the first flow expanded by the first decompressor and having been used as a refrigerant in the third heat exchanger is compressed by the multi-stage compressor.

2. The boil-off gas reliquefaction method according to claim 1 , wherein the boil-off gas compressed by the multi-stage compressor is cooled by the first heat exchanger before being supplied to the second heat exchanger.

Assignees

• Daewoo Shipbuilding & Marine

Inventors

• Lee Seung Chul
• Kim Yoon Kee

Classifications

• F25J1/0279

  Compression of refrigerant or internal recycle fluid, e.g. kind of compressor, accumulator, suction drum etc. · CPC title

• B63B25/16 Primary

  heat-insulated (insulating panelling B63B3/68; heating or cooling B63J) · CPC title

• F17C2265/033

  with cooling · CPC title

• F17C2270/0105

  Ships · CPC title

• F25J1/00

  Processes or apparatus for liquefying or solidifying gases or gaseous mixtures {(recovering volatile solvents by condensation B01D5/00; vapor recovery systems combined with filling nozzles B67D7/54; solidification of carbonic acid C01B32/55; for ammonia in general C01C1/00)} · CPC title