US 10,488,105 B2 · Method and system for separating nitrogen from liquefied natural gas using liquefied nitrogen

Abstract

A method for separating nitrogen from an LNG stream with a nitrogen concentration of greater than 1 mol %. A pressurized LNG stream is produced at a liquefaction facility by liquefying natural gas, where the pressurized LNG stream has a nitrogen concentration of greater than 1 mol %. At least one liquid nitrogen (LIN) stream is received from storage tanks, the at least one LIN stream being produced at a different geographic location from the LNG facility. The pressurized LNG stream is separated in a separation vessel into a vapor stream and a liquid stream. The vapor stream has a nitrogen concentration greater than the nitrogen concentration of the pressurized LNG stream. The liquid stream has a nitrogen concentration less than the nitrogen concentration of the pressurized LNG stream. At least one of the one or more LIN streams is directed to the separation vessel.

Claims24

Dependent claims

A method for separating nitrogen from a pressurized LNG stream with a nitrogen concentration of greater than 1 mol %, comprising:

at a liquefaction facility, producing the pressurized LNG stream by liquefying natural gas, where the pressurized LNG stream comprises a nitrogen concentration of greater than 1 mol %;
receiving at least one liquid nitrogen (LIN) stream, the at least one LIN stream being produced at a different geographic location from the liquefaction facility;
directing the at least one LIN stream to a separation vessel;
directing the pressurized LNG stream to the separation vessel;
in the separation vessel, using the at least one LIN stream to separate the pressurized LNG stream into a vapor stream and a liquid stream, where the vapor stream has a nitrogen concentration greater than the nitrogen concentration of the pressurized LNG stream and the liquid stream has a nitrogen concentration less than the nitrogen concentration of the pressurized LNG stream;
using the vapor stream to liquefy a natural gas stream to form an additional pressurized LNG stream and a warm nitrogen vent stream;
and
combining the additional pressurized LNG stream with the pressurized LNG stream upstream of the separation vessel.

5 more elements

A system for processing pressurized liquefied natural gas (LNG) produced at a liquefied natural gas (LNG) liquefaction facility, the pressurized LNG having a nitrogen concentration greater than 1 mol %, comprising:

a liquefied nitrogen (LIN) stream produced at a different geographic location from the LNG liquefaction facility;
a separation vessel into which the pressurized LNG stream and the LIN stream are directed, the separation vessel configured use the LIN stream to separate the pressurized LNG stream into a vapor stream and a liquid stream, where the vapor stream has a nitrogen concentration greater than the nitrogen concentration of the pressurized LNG stream and the liquid stream has a nitrogen concentration less than the nitrogen concentration of the pressurized LNG stream;
and
a heat exchanger that uses the vapor stream to liquefy a natural gas stream to form an additional pressurized LNG stream and a warm nitrogen vent stream;
wherein the additional pressurized LNG stream is combined with the pressurized LNG stream upstream of the separation vessel.

2 more elements

Dependencies are inferred from the claim text.

Method and system for separating nitrogen from liquefied natural gas using liquefied nitrogen

Life of this patent

Method and system for separating nitrogen from liquefied natural gas using liquefied nitrogen

Life of this patent

Abstract

Claims24