A method for the production of liquefied natural gas and liquid nitrogen is provided. The method may include providing a high pressure natural gas stream, splitting the high pressure natural gas stream into a first portion and a second portion, and liquefying the first portion of the high pressure natural gas stream to produce an LNG stream. The refrigeration needed for cooling and liquefaction of the natural gas and liquefaction of the nitrogen can be provided by a nitrogen refrigeration cycle and letdown of the second portion of the high pressure natural gas stream.

A method for the production of liquefied natural gas (LNG) and nitrogen is provided. The method may include the steps of: a) providing a nitrogen production facility, wherein nitrogen production facility comprises: a main heat exchanger, an air separation unit, a nitrogen recycle compressor, a first nitrogen refrigeration supply configured to provide refrigeration to the main heat exchanger for cooling a main air feed, b) providing a secondary refrigeration supply; c) liquefying a natural gas stream using refrigeration from the secondary refrigeration supply to form an LNG product stream; wherein the secondary refrigeration supply is configured to compress and expand a refrigerant to produce refrigeration, wherein the refrigerant of the secondary refrigeration supply is shared with refrigerant of the first nitrogen refrigeration supply

A method describing the integration of a nitrogen liquefier and letdown of natural gas for the production of liquid nitrogen and lower pressure natural gas is provided. The method may include: providing a nitrogen liquefier having a nitrogen refrigeration cycle, wherein the nitrogen liquefier comprises a nitrogen compressor, a nitrogen recycle compressor, a heat exchanger, and at least a first turbine booster and introducing a nitrogen gas stream to the nitrogen liquefier under conditions effective for liquefying the nitrogen to produce a liquid nitrogen product. The refrigeration needed to liquefy the nitrogen is provided for by the nitrogen refrigeration cycle and letdown of a high pressure natural gas stream.

A method for the integration of a nitrogen liquefier and liquefaction of natural gas for the production of liquefied natural gas and liquid nitrogen is provided. The method may include providing a nitrogen liquefaction unit and providing a natural gas liquefaction unit. Liquefaction of the nitrogen can be achieved via a nitrogen refrigeration cycle within the nitrogen liquefaction unit. Liquefaction of the natural gas can be achieved through the use of natural gas letdown and a second nitrogen refrigeration cycle. The two liquefaction units can be integrated via a common nitrogen recycle compressor, thereby providing significant capital savings.

A cryogenic fluid purification device comprising: a first container defining an interior region; a second container defining an interior region in fluid communication with the interior region of the first container; and a cryogenic fluid in contact with an exterior of the second container.

Two streams containing CO.sub.2 with different purities are separated in a common distillation column, without having been compressed or purified of water together.

In this air separation method, compressed air is successively cooled in a cooling step, purified in a purifier and sent to a cryogenic section producing at least one product containing at least one air component. The purifier comprises at least two switchable adsorber vessels, one of them being in adsorption mode. Two sources of compressed air are provided. The first source is an air grid supplying compressed air to further consumers. The second source is a dedicated main air compressor delivering compressed air to the cooling step only. Air portions from both sources are mixed at a mixing point. The air flow to the cryogenic section is controlled by measuring at least one parameter of the air flow upstream or downstream the purifier. According to such measurement, the air flow at the outlet of the main air compressor is set.

A system and method of ultra-high purity (UHP) oxygen production from an argon and oxygen producing cryogenic air separation unit incorporating a dedicated methane rejection column or column section having a liquid to vapor (L/V) ratio lower than the L/V ratio in the associated argon rectifier is provided.