| 摘要 |
The disclosure relates to a method and apparatus for cooling, preferably liquefying a boil off gas (BOG) stream from a liquefied cargo in a floating transportation vessel, said liquefied cargo having a boiling point of greater than -110° C at 1 atmosphere, said method comprising at least the steps of: - compressing a boil off gas stream (01) from said liquefied cargo in three or more stages of compression comprising at least a first stage (65), a second stage (70) and final stage (75) to provide a compressed discharge stream (06), wherein intermediate compressed BOG streams (02, 04) are provided between consecutive stages of compression; - cooling the compressed discharge stream (06) to provide a cooled compressed discharge stream (07); - heat exchanging an expanded, optionally further cooled, portion of the cooled compressed discharge stream (07), with (i) one or more intermediate compressed BOG streams (04) from consecutive stages selected from between the second and final stages (75) of compression to provide one or more cooled intermediate compressed BOG streams (05) and optionally (ii) one or more portions (07a, 108a), optionally after further cooling, of the cooled compressed discharge stream (07); and - passing the one or more cooled intermediate compressed BOG streams (05) to the next stage of compression (75). |
