The invention relates to an installation for producing liquefied gas comprising a circuit for supplying feed gas, a set of heat exchangers, a refrigerator for cooling some or all of the set of heat exchangers, the supply circuit comprising, between the set of heat exchangers and the downstream end thereof, a final expansion turbine for expanding the feed gas in liquid state, the supply circuit comprising a bypass line of the final expansion turbine fitted with a first expansion valve, a second expansion valve disposed in series upstream or downstream of the first expansion valve and of the final expansion turbine, an additional heat exchange line designed to exchange heat with a heat exchanger of the set of heat exchangers when the feed gas is expanded by the first expansion valve via the bypass line, the additional heat exchange line carrying out this heat exchange with said heat exchanger between the expansion carried out by the first expansion valve and the expansion carried out by the second expansion valve, the additional heat exchange line being located upstream or respectively downstream of the expansion carried out by the first expansion valve.

The present disclosure designs a mixed refrigerant hydrogen liquefaction device including a normal-pressure precooling cold box, a vacuum cryogenic cold box, a hydrogen refrigeration cycle compressor unit, a nitrogen cycle refrigeration unit and a mixed refrigerant cycle refrigeration unit. The precooling section uses a mixed refrigerant process and a nitrogen cycle refrigeration process as the main sources of cold energy. The refrigerant refrigeration cycle is the main source of cold energy in the temperature range of 303K to 113K. The liquid nitrogen refrigeration cycle is the main source of cold energy in the temperature range of 130K to 80K. The hydrogen refrigeration cycle provides cold energy for the temperature range of 80K to 20K. Most of the BOG generated in a storage part is recovered by an ejector. A plate-fin heat exchanger is filled with ortho-para hydrogen conversion catalysts to realize the para hydrogen content of liquefied hydrogen 98%.

The invention relates to a device (200) for liquefying a gas (51), the device comprising: a circuit (55) for conveying gas to be liquefied, the circuit comprising at least one heat exchanger (204) for exchanging heat between the gas (51) to be liquefied and a refrigerant flow (52) comprising at least dihydrogen refrigerant; a closed refrigeration circuit (210) configured to convey the refrigerant flow,
the closed refrigeration circuit comprising a means (215) for maintaining an internal composition of the dihydrogen refrigerant at a ratio of parahydrogen to orthohydrogen that is lower or higher than the ratio corresponding to a natural equilibrium composition in the refrigerant flow closed circuit, the means (215) comprising a catalytic reactor (220) configured to convert some of the orthohydrogen from the dihydrogen refrigerant flow into parahydrogen or vice versa.

Systems and methods are provided for recovering helium from a feed comprising helium, carbon dioxide, and at least one of nitrogen and methane. The feed is separated in a first separator to form helium-enriched stream and a CO.sub.2-enriched stream. The helium-enriched stream is separated in a pressure swing adsorption unit to form a helium-rich product stream and a helium-lean stream. At least a portion of the helium-lean stream is recycled to the first separator with the feed. In some embodiments, a membrane separation unit is used to enhance helium recovery.

Methods are for storing electricity and producing liquefied natural gas (LNG) or synthetic natural (SNG) and using carbon dioxide and for producing electricity, natural gas (NG) or SNG. The methods involve, starting from a water flow, producing an oxygen gas flow and a hydrogen gas flow by electrolysis in an electrolytic cell. A first hydrogen gas flow portion and a second hydrogen gas flow portion are obtained. The first hydrogen gas flow portion is allocated to a methanation step in the presence of carbon dioxide gas. A condensed recirculation water vapor flow is obtained to be allocated to the methanation step and performing methanation. The second hydrogen gas flow portion is allocated to a cooling and liquefaction step. A liquid hydrogen flow is obtained, which is stored in a liquid hydrogen tank.

Methods and systems providing a process for cooling and liquefying a purified gaseous hydrogen feed stream to a liquid hydrogen stream that may be stored in a liquid hydrogen storage tank, as well as a system wherein ortho-hydrogen (o-H2) contained in the purified gaseous hydrogen feed stream may be converted to para-hydrogen (p-H2) through serial low-temperature catalytic converters along the cooling process from normal ambient temperature (300K) to the liquefied temperature about (20K) of the hydrogen.

An apparatus and process for recycling hydrogen can be provided so that hydrogen is recycled during hydrogen liquefaction processing to account for an unexpected loss of feed of hydrogen so the recycled hydrogen can be provided to avoid liquefier operations having to be shut down. Embodiments can utilize a parahydrogen to ortho-hydrogen conversion unit to facilitate such recycling of hydrogen to avoid liquefaction processing problems in liquefaction of the recycled hydrogen included into the feed to account for the loss of fee hydrogen.

The invention relates to a facility and a method for the liquefaction of hydrogen, comprising a hydrogen circuit having an upstream end configured to be connected to a source of gaseous hydrogen and a downstream end connected to at least one store, the facility comprising a cold box housing a set of heat exchangers in a heat exchange relationship with the hydrogen circuit, the facility comprising a cooling device in a heat exchange relationship with at least part of the set of heat exchangers, the facility comprising a collecting pipe configured to collect boil-off gas and equipped with at least one upstream end connected to the store and/or a tank to be filled, and a downstream end connected to the hydrogen circuit, inside the cold box, said downstream end of the collecting pipe comprising, ahead of its connection to the hydrogen circuit, a portion in a heat exchange relationship with at least one heat exchanger of the set of heat exchangers.

Methods and systems providing a process for cooling and liquefying a purified gaseous hydrogen feed stream to a liquid hydrogen stream that may be stored in a liquid hydrogen storage tank, as well as a system wherein ortho-hydrogen (o-H2) contained in the purified gaseous hydrogen feed stream may be converted to para-hydrogen (p-H2) through serial low-temperature catalytic converters along with cooling process from normal ambient temperature (300K) to the liquefied temperature (about 20K) of the hydrogen.