Patent ID: 8973398
Filing Date: 2015-03-10
Classification: F17C,F25J

Abstract:
1. A method for vaporizing a liquefied natural gas stream and recovering LPG therefrom comprising: flowing a first stream of liquefied natural gas having a first temperature from a LNG storage tank to a first heat exchanger; heating the first stream of liquefied natural gas in the first heat exchanger to a second temperature; introducing the first stream of liquefied natural gas at about the second temperature to a LPG recovery column; fractionating the first stream of liquefied natural gas at about the second temperature in the LPG recovery column to produce a first lean natural gas stream and LPG; compressing natural gas vapors from the LNG storage tank to form a natural gas vapor stream; introducing the natural gas vapor stream to the LPG recovery column at a location below where the first stream of liquefied natural gas at about the second temperature is introduced; providing heat to the LPG recovery column with a first heat transfer fluid stream in a reboiler, wherein the first heat transfer fluid stream exits the reboiler as a second heat transfer fluid stream, the second heat transfer fluid stream having a temperature less than ambient temperature; vaporizing at least a portion of the first lean natural gas stream in a second heat exchanger with a third lean natural gas stream to produce a second lean natural gas stream; heating the second lean natural gas stream in a third heat exchanger with a first portion of a third heat transfer fluid stream to produce the third lean natural gas stream; cooling the third lean natural gas stream in the second heat exchanger with the first lean natural gas stream to produce a fourth lean natural gas stream; heating the fourth lean natural gas stream in a fourth heat exchanger with a second portion of the third heat transfer fluid stream to produce a fifth lean natural gas stream suitable for delivery to a pipeline or for commercial use; and cooling a first air stream by heat exchange with at least a portion of the second heat transfer fluid stream to produce a first chilled air stream and a fourth heat transfer fluid stream, wherein the first chilled air stream is an inlet air stream to a fired turbine.