Method Of Cooling Boil Off Gas And An Apparatus Therefor
AssigneeLGE IP Management Company Limited
InventorMartin Halcrow
Life of this patent
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Abstract
A method of cooling a boil off gas stream from a liquefied cargo (50a) in a floating transportation vessel is described. The method comprises: compressing a boil off gas stream in two or more stages of compression to provide a compressed BOG discharge stream; cooling the compressed BOG discharge stream against one or more first coolant streams to provide a first cooled compressed BOG stream; cooling the first cooled compressed BOG stream against at least one second coolant stream to provide a second cooled compressed BOG stream; providing a vessel fuel stream from the liquefied cargo; using the vessel fuel stream as a coolant stream to cool either the compressed BOG discharge stream, or the first cooled compressed BOG stream, or both said streams.
Claims26
A method of cooling 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 the steps of:
- compressing a BOG stream from said liquefied cargo in at least two stages of compression comprising a first stage and a final stage to provide a compressed BOG discharge stream, wherein said first stage of compression has a first stage discharge pressure and said final stage of compression has a final stage suction pressure, and at least one intermediate compressed BOG streams is provided between consecutive stages of compression;
- cooling the compressed BOG discharge stream against one at least one first coolant streams to provide a first cooled compressed BOG stream;
- cooling the first cooled compressed BOG stream against at least one second coolant stream to provide a second cooled compressed BOG stream;
- providing a vessel fuel stream from the liquefied cargo;
- using the vessel fuel stream as a coolant stream to cool one or both of the compressed BOG discharge stream and the first cooled compressed BOG stream.
An apparatus to cool a boil off (BOG) gas stream from a liquefied cargo, said liquefied cargo having a boiling point of greater than −110° C. at 1 atmosphere, in a floating transportation vessel comprising a plurality of components, said apparatus comprising at least:
- a compression system to compress a BOG stream from a liquefied cargo, said compression system comprising at least two stages of compression comprising at least a first stage and a final stage to provide a compressed BOG discharge stream, wherein at least one intermediate compressed BOG streams is provided between consecutive stages of compression,
- one or more first heat exchangers to cool the compressed BOG discharge stream to provide a first cooled compressed BOG stream;
- at least one second heat exchanger to further cool the first cooled compressed BOG stream against a mixed phase coolant stream to be separated in the one or more second heat exchangers, to provide a second cooled compressed BOG stream;
- at least one vessel fuel heat exchanger to cool one or both of the compressed BOG discharge stream and the first cooled compressed BOG stream, using a vessel fuel stream as a coolant stream.
24-25. (canceled)
A method of designing an apparatus for cooling a boil off gas (BOG) stream from a liquefied cargo in a floating transportation vessel comprising a plurality of components, said liquefied cargo having a boiling point of greater than −110° C. at 1 atmosphere, comprising the steps of:
- selecting a compression system to compress a BOG stream from a liquefied cargo, said compression system comprising at least two stages of compression comprising at least a first stage and a final stage to provide a compressed BOG discharge stream, wherein at least one intermediate compressed BOG stream is provided between consecutive stages of compression,
- selecting one or more first heat exchangers to cool the compressed BOG discharge stream to provide a first cooled compressed BOG stream;
- selecting one or more second heat exchangers to further cool the first cooled compressed BOG stream against a mixed phase coolant stream to be separated in the one or more second heat exchangers to provide a second cooled compressed BOG stream;
- selecting one or more third heat exchangers to further cool the second cooled compressed BOG stream to provide a third cooled compressed BOG stream;
- and
- selecting one or more vessel fuel heat exchangers to cool one or both of the compressed BOG discharge stream and the first cooled compressed BOG stream, or both said streams, using a vessel fuel stream as a coolant stream.
27-29. (canceled)
Dependencies are inferred from the claim text.