A technology liquefies natural gas. The natural gas liquefaction method pre-cools treated natural gas by ethane evaporation, sub-cools liquefied gas using cooled nitrogen as a refrigerant, reduces liquefied gas pressure, separates non-liquefied gas and diverts liquefied natural gas. Before pre-cooling the natural gas is compressed, ethane is evaporated during the multi-stage pre-cooling of liquefied gas with simultaneous evaporation of ethane using cooled ethane as a refrigerant. Ethane generated by evaporation is compressed, condensed and used as a refrigerant during the cooling of liquefied gas and nitrogen, with nitrogen being compressed, cooled, expanded and fed to the natural gas sub-cooling stage. The natural gas liquefaction unit contains a natural gas liquefaction circuit, an ethane circuit and a nitrogen circuit. The natural gas liquefaction circuit includes a natural gas compressor, a cooler unit, ethane vaporizers, a closed-end subcooling heat exchanger, and a separator, connected in series.

A system for the regeneration of nitrogen energy within a closed loop cryogenic system is described. A liquid nitrogen storage is provided in fluid communication with a first flow line. A pump pumps liquid nitrogen from the liquid nitrogen storage to the first flow line. At least one cryogenic cooling loop is provided in fluid communication with the first flow line. The cryogenic cooling loop has an nitrogen intake and a nitrogen outlet with the nitrogen outlet being positioned downstream of the nitrogen intake. The cryogenic cooling loop has a heat exchanger between the nitrogen intake and the nitrogen outlet. A turbo expander used for re-cooling the nitrogen flowing through the first flow line and the at least one cryogenic cooling loop has an inlet and an outlet. The inlet is provided in fluid communication with the first flow line. The turbo expander is connected to a power source. A second flow line connects the outlet of the turbo expander to the liquid nitrogen storage.

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 system for processing an LNG feed, the system comprising: a bulk removal stage arranged to remove and release CO.sub.2 liquid from the inflow feed, said bulk removal stage including a first HGMT device, and; a polishing stage arranged to receive a lean CO.sub.2 feed from the first HGMT device, said polishing stage arranged to remove and release residual CO.sub.2, the polishing stage including a second HGMT device; wherein the polishing stage is arranged to release an outflow of CO.sub.2 stripped LNG.

A process for producing biomethane by scrubbing a biogas feed stream includes introducing the feed gas stream into a pretreatment unit wherein a CO.sub.2-depleted gas stream is partially separated from a CO.sub.2 stream and an oxygen stream and is compressed to a pressure P1 above 25 bar abs. Subjecting the CO.sub.2-depleted gas stream to cryogenic separation in a distillation column to separate a nitrogen stream and produce a CH.sub.4-enriched stream, the distillation column comprising n plates, n being an integer between 8 and 100. Recovering a pressurized CH.sub.4-enriched stream by pumping the CO.sub.2-depleted gas stream to a pressure P2 above 25 bar absolute.

The present invention relates to a cold box cycle which allows for independent control of the heat supplied for reboilers associated with the separation columns. More specifically, the invention relates to the tight control of the hydrogen removal separation, thus avoiding the possibility of excess reboiling in this separation. Optimal reboiling also results in a lower temperature of the hydrogen depleted liquid from this separation. As this stream is used to provide a portion of the cooling at the cold end of the primary heat exchanger, lower temperatures facilitate cooling of the incoming syngas feed, reducing carbon monoxide (CO) losses into the crude hydrogen stream from the high pressure separator. Lower CO in the crude hydrogen allows for smaller hydrogen purification equipment.

The invention relates to a process and device for the cryogenic separation of a methane-containing feed gas predominantly consisting of hydrogen and carbon monoxide, that is partially condensed in this case by cooling, in order to obtain a hydrogen-containing first liquid phase predominantly consisting of carbon monoxide and methane, from which first liquid phase, in an H.sub.2 separation column that is heated via a circulation heater, a second liquid phase is generated by separating off hydrogen, from which second liquid phase, in a CO/CH.sub.4 separation column, a carbon monoxide-rich gas phase is obtained having a purity that permits release thereof as carbon monoxide product. It is characteristic in this case that a low-methane material stream is withdrawn from the H.sub.2 separation column and is then applied to the CO/CH.sub.4 separation column as reflux.

A carbon dioxide capturing apparatus using cold heat of liquefied natural gas (LNG) includes a heat exchanger to cool primary coolant using heat exchange between the primary coolant and the LNG; a chiller connected to the heat exchanger and configured to discharge capturing coolant colder than the primary coolant by performing a heat exchange between the capturing coolant and a cooling material; and a capturing cooler configured to capture carbon dioxide contained in flue gas by performing a heat exchange between the capturing coolant discharged from the chiller and the flue gas. A power generation system includes an LNG storage facility; a power generation facility discharging flue gas; a unit for heat exchange between the LNG and a coolant to regasify the LNG and cool the coolant; and a unit for capturing carbon dioxide contained in the flue gas by heat exchange between the discharged flue gas and the coolant.

A process for producing biomethane by scrubbing a biogas feed stream including introducing a feed gas stream into a pretreatment unit wherein the gas stream is partially separated from a CO.sub.2 stream and an oxygen stream, thereby producing a CO.sub.2-depleted gas stream, which is compressed, thereby producing a pressurized CO.sub.2-depleted gas stream; separating the pressurized CO.sub.2-depleted gas stream by cryogenic separation by introducing the pressurized CO.sub.2-depleted gas stream into a distillation column thereby producing a nitrogen stream and a CH.sub.4-enriched stream, recovering a pressurized CH.sub.4-enriched stream by pumping the CH.sub.4-enriched stream; wherein the separation of the CO.sub.2 stream and the oxygen stream from the feed gas stream is performed by a unit comprising at least two separating membrane stages in order that the CO.sub.2-depleted gas stream comprises between 0.3 mol % and 2 mol % of CO.sub.2.

A technology liquefies natural gas. The natural gas liquefaction method pre-cools treated natural gas by ethane evaporation, sub-cools liquefied gas using cooled nitrogen as a refrigerant, reduces liquefied gas pressure, separates non-liquefied gas and diverts liquefied natural gas. Before pre-cooling the natural gas is compressed, ethane is evaporated during the multi-stage pre-cooling of liquefied gas with simultaneous evaporation of ethane using cooled ethane as a refrigerant. Ethane generated by evaporation is compressed, condensed and used as a refrigerant during the cooling of liquefied gas and nitrogen, with nitrogen being compressed, cooled, expanded and fed to the natural gas sub-cooling stage. The natural gas liquefaction unit contains a natural gas liquefaction circuit, an ethane circuit and a nitrogen circuit. The natural gas liquefaction circuit includes a natural gas compressor, a cooler unit, ethane vaporizers, a closed-end subcooling heat exchanger, and a separator, connected in series.