An LNG plant comprises a cold box and a refrigeration unit fluidly coupled with a plurality of heat exchanger passes in the cold box. The refrigeration unit is configured to provide a first refrigerant stream to a first heat exchanger pass of the plurality of heat exchanger passes at a first pressure, a second refrigerant stream to a second heat exchanger pass at a second pressure, and a third refrigerant stream to a third heat exchanger pass at a third pressure. The second refrigerant stream comprises a first portion of the first refrigerant stream, and the third refrigerant stream comprises a second portion of the first refrigerant stream. The second pressure and the third pressure are both below the first pressure. The cold box is configured to produce LNG from a natural gas feed stream to the cold box using a refrigeration content from the refrigeration unit.

Devices, systems, facilities, and processes for CO.sub.2 capture at Liquid Natural Gas (LNG) facilities using self-generated electric power. The process includes a pretreatment unit located upstream of the power generating station and liquefaction facility to remove at least one of water, CO.sub.2, or one or more heavy hydrocarbons. The CO.sub.2 captured from the pretreatment unit, along with the CO.sub.2 captured from the power generating station flue gas may be sent to a sequestration compressor, thereby reducing the overall emissions.

The present invention comprises systems and methods for natural gas liquefaction. In embodiments, the systems comprise a dual turbo-expander, methane-based refrigeration system that also uses a slip stream of LNG for additional cooling.

The systems and methods described herein integrate a supercritical fluid power generation system with a LNG production/NGL separation system. A heat exchanger thermally couples the supercritical fluid power generation system with the LNG production/NGL separation system. A relatively cool heat transfer medium, such as carbon dioxide, passes through the heat exchanger and cools a first portion of extracted natural gas. The relatively warm heat transfer medium returns to the supercritical fluid power generation system where a compressor and a thermal input device, such as a combustor, are used to increase the pressure and temperature of the heat transfer medium above its critical point to provide a supercritical heat transfer medium. A second portion of the extracted natural gas may be used as fuel for the thermal input device.

A process for cryogenic separation of a feed stream containing methane and air gases in which: the feed stream is cooled in order to produce a cooled stream, at least one portion of the cooled stream is sent to one level of a distillation column, a bottom stream is drawn off from the distillation column, the bottom stream being enriched in methane relative to the feed stream, a stream enriched in oxygen and in nitrogen relative to the feed stream is drawn off from the distillation column, at least one noncombustible dilution stream that is more volatile than oxygen is introduced into the distillation column at at least one level lower than the one at which the cooled stream is introduced. The dilution stream is extracted from the feed stream. Facility for producing biomethane by purification of biogases derived from non-hazardous waste storage facilities (NHWSF) implementing the process.

A natural gas liquefying apparatus is provided. At least a part of a cooling region, in which a precooling unit and a liquefaction unit are arranged, and at least a part of a compression region, in which first and second compressors compressing refrigerants to be used in the precooling unit and the liquefaction unit are arranged, are arranged to be opposed to each other across a long side of a second refrigerant cooler group arrangement region in which a liquefying refrigerant is cooled. A first refrigerant cooler group arrangement region, in which a precooling refrigerant is cooled, is arranged so that a long side of the first refrigerant cooler group arrangement region is opposed to one side of a rectangular region including the compression region, the one side being different from a side of the rectangular region opposed to a long side of the second refrigerant cooler group arrangement region.

A method for liquefying production gas from a gas source containing a fluid having C1-C12 entrained gases includes passing the gas through a first stage of cryogenic liquefaction to cool the gas to a temperature between −50 degrees Celsius and −87 degrees Celsius to create a fluid containing a liquefied C3-C12 petroleum gas and a gaseous C1-C2 natural gas. The liquefied C3-C12 petroleum gas and gaseous C1-C2 natural gas are passed through a second phase separator to separate the liquefied C3-C12 petroleum gas from the gaseous C1-C2 natural gas. The liquefied C3-C12 petroleum gas is collected into liquefied petroleum gas storage vessels.

Method and system for removing high freeze point components from natural gas. Feed gas is cooled in a heat exchanger and separated into a first vapor portion and a first liquid portion. The first liquid portion is reheated using the heat exchanger and separated into a high freeze point components stream and a non-freezing components stream. A portion of the non-freezing components stream may be at least partially liquefied and received by an absorber tower. The first vapor portion may be cooled and received by the absorber tower. An overhead vapor product which is substantially free of high freeze point freeze components and a bottoms product liquid stream including freeze components and non-freeze components are produced using the absorber tower.

Process for extracting nitrogen from a feed stream of natural gas or of biomethane comprising at least nitrogen, methane, CO.sub.2 and/or H.sub.2S, wherein a liquid stream enriched in methane resulting from a cryogenic separation is recovered by pumping the bottom product of one or more of the columns and/or pumping a liquid stream to a pressure P2 greater than 25 bar absolute and preferably greater than the critical pressure of said product.

A cryogenic distillation tower for separating a feed stream. The tower includes a distillation section. A controlled freeze zone section is situated above the distillation section and forms a solid from the feed stream. The controlled freeze zone section includes a spray assembly in an upper section and a melt tray assembly in a lower section. The melt tray assembly includes at least one vapor stream riser that directs the vapor from the distillation section into liquid retained by the melt tray assembly, and one or more draw-off openings positioned to permit a portion of the liquid to exit the controlled freeze zone section. The portion of the liquid indirectly exchanges heat with a heating fluid. One or more return inlets return the portion of the liquid to the melt tray assembly after it has been heated in the heat exchanger.