A system and method for processing natural gas to produce liquefied natural gas is disclosed. The natural gas is cooled in one or more heat exchangers using a first refrigerant from a first refrigerant circuit in which the first refrigerant is compressed in a first compressor driven by a first gas turbine having a first inlet air stream. The natural gas is liquefied using a second refrigerant, the second refrigerant being compressed in a second compressor driven by a second gas turbine having a second inlet air stream. At least one of the inlet air streams is chilled from about the respective dry bulb temperature to a temperature below the respective wet bulb temperature. Water contained in at least one of the chilled first and second air streams is condensed and separated therefrom. At least a portion of the first refrigerant is condensed or sub-cooled using the separated water.

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.

Described herein are methods and systems for removing natural gas liquids from a natural gas feed stream and for liquefying the natural gas feed stream so as to produce a liquefied natural gas (LNG) stream and a natural gas liquids (NGL) stream

A system for cooling a gas includes a pre-cool heat exchanger and a liquefaction heat exchanger. The pre-cool heat exchanger uses a pre-cool refrigerant to pre-cool a feed gas stream prior to the stream being directed to a liquefaction heat exchanger. The liquefaction heat exchanger uses a mixed refrigerant to further cool the pre-cooled gas. The pre-cool heat exchanger also pre-cools the liquefaction mixed refrigerant used by the liquefaction heat exchanger.

Processes and systems are provided for recovering a liquid natural gas (LNG) from a hydrocarbon-containing gas. More particularly, the present invention is generally related to processes and systems that optimize the chilling efficiencies of an LNG facility through the utilization of an auxiliary refrigeration cycle. Additionally, the present invention is also generally related to the rerouting of mixed refrigerants in a closed-loop refrigeration cycle in order to optimize the chilling efficiencies of the LNG facility.

The device (400) for liquefying a natural gas comprises: a compressor (105) of a first vaporized coolant chemical mixture, a means (110) for fractionating the compressed mixture into a heavy fraction and a light fraction, a first body (115) for exchanging heat between the heavy fraction of the first mixture and the natural gas to cool at least the natural gas, a second body (120) for exchanging heat between the light fraction of the first mixture and the natural gas cooled in the first exchange body to liquefy the natural gas, a conduit (125) for returning the first vaporized coolant mixture in the heat exchange bodies to the compressor, a regulator (405) for the liquefied natural gas, a collector (410) for the evaporation gas produced during the expansion of the gas in the regulator, a conduit (415) for injecting the evaporation gas at the inlet of the second exchange body, upstream of an inlet (116) for the natural gas in the first exchange body (115), a third body (420) for exchanging heat between the natural gas and a second chemical coolant compound, a means (425) for compressing the second vaporized compound, a means (430) for cooling the second compressed compound and a conduit (435) for transferring the second cooled compound towards the third exchange body.

A process for liquefying a natural gas comprising a mixture of hydrocarbons predominating in methane, the process comprising a first semi-open refrigerant cycle with natural gas in which any natural gas liquids that have condensed are separated from the natural gas feed stream, which stream then passes through a main cryogenic heat exchanger (4) in order to contribute by heat exchange to pre-cooling a main natural gas stream (F-P) and to cooling an initial refrigerant gas stream (G-0), a second semi-open refrigerant cycle with natural gas for contributing to pre-cooling the natural gas and the refrigerant and also to liquefying the natural gas, and a closed refrigerant cycle with refrigerant gas for subcooling the liquefied natural gas and for delivering refrigeration power in addition to the other two cycles. The invention also provides a natural gas liquefaction installation for performing such a process.

The device (100) for liquefying a natural gas comprises: a compressor (105) for a first vaporized coolant chemical mixture, a means (110) for fractionating the compressed mixture into a heavy fraction and a light fraction, a first heat exchange body (115) for heat exchange between the heavy fraction of the first mixture and the natural gas in order to cool at least the natural gas, a second heat exchange body (120) for heat exchange between the light fraction of the first mixture and the cooled natural gas in the first exchange body in order to liquefy the natural gas, and a return pipe (125) for return of the first vaporized coolant mixture in the heat exchange body to the compressor (105), upstream from an inlet (116) for the natural gas in the first exchange body (115) or downstream from an outlet (121) of liquefied natural gas from the second exchange body (120), a third heat exchange body (130, 135) for heat exchange between the natural gas and a second coolant chemical compound, and a means (140, 145) for compressing the second vaporized compound.

A process for producing liquefied natural gas and liquid carbon dioxide from a natural gas feed gas comprising at least the following steps: Separation of a natural gas feed gas into a CO.sub.2-enriched gas stream and a natural gas stream; Cooling of said natural gas in a heat exchanger; Purification of the in step 1 from compounds containing at least six carbon atoms; At least partial condensation of said gas stream resulting from step 3 to form a two-phase stream; Separation of said two-phase stream resulting from step 4 to form a gas stream and a liquid stream; Condensation of the gas stream resulting from step 5 to form a liquefied gas containing less than 5 ppm by volume of compounds containing at least six carbon atoms; Liquefaction of the CO.sub.2-enriched gas stream resulting from step 1 with a portion of the liquid stream resulting from step 5.

A compressor system is disclosed, including a first compressor unit having: at least a first gas inlet at a first gas pressure level; a second gas inlet at a second gas pressure level; and a gas discharge; a second compressor unit having: at least a third gas inlet at a third gas pressure level; a fourth gas inlet at a fourth gas pressure level; and a gas delivery. The gas discharge of the first compressor unit is fluidly coupled to one of the third gas inlet and fourth gas inlet of the second compressor unit.