Patent ID: 8156758
Filing Date: 2012-04-17
Classification: F25J

Abstract:
1. 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: (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duty for the fractionation system by withdrawing a fraction of the LNG before being heated and passing the withdrawn fraction to the fractionation system and passing at least a portion of the methane-rich vapor stream produced by the fractionation system in heat exchange with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.