Described herein are systems and processes to produce liquefied natural gas (LNG) using liquefied nitrogen (LIN) as the refrigerant. Greenhouse gas contaminants are removed from the LIN using a greenhouse gas removal unit. The LNG is compressed prior to being cooled by the LIN.

An ultra-high-purity oxygen production method and apparatus are provide, in which the method can include a step in which feed oxygen comprising low-boiling-point components as impurities is introduced from a warm end of a main heat exchanger and cooled, then introduced into an oxygen rectification column, and product ultra-high-purity oxygen from which the low-boiling-point components have been removed is drawn as a gas or a liquid from a lower portion of the oxygen rectification column.

A system and method for providing supplemental refrigeration to an air separation plant is provided. A closed loop supplemental refrigeration circuit that can be easily retrofitted or added onto an air separation plant that increases the liquid product production capability of the air separation plant. The supplemental refrigeration capacity of the supplemental refrigeration circuit is controlled by removing or adding a portion of the refrigerant in the supplemental refrigeration circuit to adjust the inlet pressure while maintaining a substantially constant volumetric flow rate and substantially constant pressure ratio across the compressor. Removing the refrigerant from the supplemental refrigeration circuit decreases the refrigeration imparted by the supplemental refrigeration circuit and thus provides the capacity to turn-down liquid product make without shutting down the compressors and turbo-expanders in the supplemental refrigeration circuit.

A method for cooling a hydrocarbon production stream such as natural gas uses cryogenic nitrogen as a cooling medium (refrigerant) wherein only a portion of a nitrogen refrigerant stream is recovered, with a vapor portion of the nitrogen refrigeration stream being vented from the system. Unlike a conventional sacrificial nitrogen refrigeration process which vents all the nitrogen refrigerant after cooling a production stream, the method comprise means for recovering some of the nitrogen refrigerant thereby improving the operating efficiency of the process compared to conventional sacrificial nitrogen refrigeration processes. Also unlike conventional closed loop nitrogen refrigeration processes which recover all of the nitrogen refrigerant after cooling a production stream, the method can recover nitrogen refrigerant without the complex and costly equipment used in closed loop systems to compress nitrogen vapor.

A method for the production of liquefied natural gas (LNG) using a cold fluid provided from a cryogenic unit, such as an air separation unit or nitrogen liquefier, is provided. The method may include the steps of: withdrawing a nitrogen stream from a cryogenic unit, wherein the nitrogen stream is at a temperature between about 155 C. to about 193 C.; and liquefying a natural gas stream in a natural gas liquefaction unit using the nitrogen stream from the cryogenic unit.

A hydrogen liquefaction system that utilizes two separate compression services, one controlled via pressure and the other via capacitance, to maintain the rotating equipment at its design point. The system also employs an intermediate flash drum to capture boil off gas and a catalyst bed to convert para-hydrogen into ortho-hydrogen. Changing pressure levels within the turbo expander loop are used to transfer hydrogen from the expander loop into the condensate or feed streams, while maintaining the condensate stream at a constant pressure. The system is capable of efficiently producing high-purity liquid hydrogen at a low cost, making it a valuable tool in industries such as fuel cells, energy storage, and aerospace.

A method is provided for separating off acid gases, in particular CO.sub.2 and H.sub.2S, from a hydrocarbon-rich fraction, in particular natural gas. The hydrocarbon-rich fraction is cooled and partially condensed. The resultant CO.sub.2-enriched liquid fraction is separated by rectification into a CO.sub.2-rich liquid fraction and a CO.sub.2-depleted gas fraction. The hydrocarbon-rich fraction is cooled close to the temperature of the CO.sub.2 triple point by means of a closed multistage refrigeration circuit. The refrigerant is a CO.sub.2 fraction of greater than 99.5% by volume. The rectification column is operated at a pressure between 40 and 65 bar. The reboiler of the rectification column is heated by means of a condensing refrigerant substream of the refrigeration circuit that is at a suitable pressure level.

The invention relates to an invention for the liquefaction of hydrogen, comprising a supply circuit for supplying hydrogen to be cooled, a plurality of heat exchangers arranged in heat exchange with the supply circuit, a first pre-cooling device, a second pre-cooling device and a cooling system in heat exchange with the set of exchangers, to reduce the temperature of the hydrogen to a temperature below the critical temperature of hydrogen, the first pre-cooling device comprising a refrigerator having a closed refrigeration cycle for a first cycle gas comprising at least three components, a first centrifugal compressor, a cooling member, three phase separators configured to separate the two-phase fluid, the refrigerator having a refrigeration cycle of the first pre-cooling device comprising a first expansion member configured to expand the liquid produced by one of the phase separators and to return this fluid to a first centrifugal compressor via a passage through a heat exchanger of the set of exchangers.

A method for energy storage with co-production of peaking power and liquefied natural gas (LNG) which integrates the processes of liquid air energy storage and reduction in pressure of natural gas through expander at the co-located city gate station and includes consumption of excessive power from the grid, mechanical power of the natural gas expander and cold thermal energy of expanded natural gas for charging the storage with a liquid air during off-peak hours and production of peaking (on-demand) power by the expanders of natural gas and highly-pressurized re-gasified air with recovering the cold thermal energy of expanded natural gas and regasified liquid air for liquefying a part of delivered natural gas at the city gate station and energy storage facility.

The method for producing liquid hydrogen can include the steps of: introducing pressurized natural gas from a high pressure natural gas pipeline to a gas processing unit under conditions effective for producing a purified hydrogen stream; and introducing the purified hydrogen stream to a hydrogen liquefaction unit under conditions effective to produce a liquid hydrogen stream, wherein the hydrogen liquefaction unit provides a warm temperature cooling and a cold temperature cooling to the purified hydrogen stream, wherein the warm temperature cooling is provided by utilizing letdown energy of a pressurized stream selected from the group consisting of a nitrogen stream sourced from a nitrogen pipeline, a natural gas stream sourced from the high pressure natural gas pipeline, an air gas sourced from an air separation unit, and combinations thereof, wherein the cold temperature is provided by utilizing letdown energy of the purified hydrogen stream.