Patent ID: 8156758

Claim:
A method of processing liquefied natural gas (LNG), comprising two alternative modes of operation: (a) operating in a first mode for recovering a portion of natural gas liquids (NGL) by: passing LNG through a heat exchanger to provide heated LNG; fractionating the heated LNG into a methane-rich vapor stream and a natural gas liquids (NGL) stream; passing the methane-rich vapor stream through the heat exchanger, without increasing the pressure of the methane-rich vapor stream, to transfer heat from the methane-rich vapor stream to the LNG passing through the heat exchanger and to provide a two-phase stream that includes a methane-rich liquid phase and a methane-rich vapor phase; separating the two-phase stream in a vapor liquid separator into at least a methane-rich liquid portion and a methane-rich gas portion; increasing the pressure of the methane-rich liquid portion to provide a sendout liquid stream; recovering the sendout liquid stream to provide a sales gas for delivery to a pipeline; and (b) operating in a second mode for rejecting a portion of NGL by diverting the LNG to a diverted flow path that bypasses the fractionating to provide sales gas that includes methane and ethane plus for delivery to the pipeline; wherein in mode (a), mode (b), or both mode (a) and (b) the following steps are performed: providing at least part of a refrigeration duty for the fractionation system by withdrawing a fraction of the LNG before being heated and passing the withdrawn fraction to the fractionation system and passing at least a portion of the methane-rich vapor stream produced by the fractionation system in heat exchange with the LNG to effect cooling of the methane-rich vapor stream and passing at least a portion of the cooled stream to the fractionation system, and heat exchanging the NGL stream with the heated LNG to provide a chilled NGL stream; and flashing the chilled NGL stream to substantially atmospheric pressure to provide a flashed NGL stream, wherein the fractionation system comprises a reflux input in fluid communication with a portion of the liquid recovered in the vapor-liquid separator.