Apparatus and method for regasification of liquefied natural gas

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;
• recovering at least a portion of the LPG from the LPG recovery column;
• 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 duty 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;
• cooling a first air stream with at least a portion of the second heat transfer fluid stream in one or more heat exchangers to produce a first chilled air stream and a third heat transfer fluid stream, wherein the first chilled air stream is inlet air stream to a fired turbine;
• heating the first stream of liquefied natural gas in the first heat exchanger with the first lean natural gas stream from the LPG recovery column to at least partially vaporize the first stream of liquefied natural gas prior to the LPG recovery column;
• 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 fourth 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;
• and
• heating the fourth lean natural gas stream in a fourth heat exchanger with a second portion of the fourth heat transfer fluid stream to produce a fifth lean natural gas stream suitable for delivery to a pipeline or for commercial use.

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;
• recovering at least a portion of the LPG from the LPG recovery column;
• 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 duty 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;
• cooling a first air stream with at least a portion of the second heat transfer fluid stream in one or more heat exchangers to produce a first chilled air stream and a third heat transfer fluid stream, wherein the first chilled air stream is an inlet air stream to a fired turbine;
• compressing the first lean natural gas stream;
• condensing the compressed first lean natural gas stream to a liquid state with the first stream of liquefied natural gas in the first heat exchanger to at least partially vaporize the first stream of liquefied natural gas prior to the LPG recovery column;
• vaporizing at least a portion of the condensed first lean natural gas stream in a second heat exchanger with the 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 fourth heat transfer fluid stream to produce a third lean natural gas stream;
• cooling the third lean natural gas stream in the second heat exchanger with the condensed 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 fourth heat transfer fluid stream to produce a fifth lean natural gas stream suitable for delivery to a pipeline or for commercial use;
• and
• heating at least a portion of the third heat transfer fluid stream and at least a portion of the fourth heat transfer fluid stream with an exhaust stream of the fired turbine in a heat exchanger.