A raw material gas liquefying device includes a feed line; a refrigerant circulation line; and a controller. In a refrigerant liquefaction route, a refrigerant flows through a compressor, a heat exchanger, a circulation system JT valve, a liquefied refrigerant storage tank, and the heat exchanger, and returns to the compressor. In a cryogenic energy generation route, the refrigerant flows through the compressor, the heat exchanger, an expansion unit, and the heat exchanger, and returns to the compressor. The controller determines if a refrigerant storage tank liquid level is within an allowable range, manipulates a feed system JT valve opening rate to control refrigerant temperature at the high-temperature-side refrigerant flow path exit side of the heat exchanger, and manipulates the opening rate of the feed system JT valve to control the refrigerant storage tank liquid level so that the refrigerant storage tank liquid level falls into the predetermined allowable range.

A liquefaction and subcooling system, comprising a refrigeration device to provide a refrigerant fluid at a first and a second cold temperature that correspond to temperatures of the first and second gases, a subcooling arrangement coupled to the refrigeration device such that the refrigerant fluid is supplied to the subcooling arrangement, the subcooling arrangement having first and second subcoolers for exchanging heat between a gas to be liquefied and/or subcooled and the refrigerant fluid, wherein, when the gas to be liquefied and/or subcooled is the first gas, the refrigeration device is configured to provide the refrigerant fluid and the subcooling arrangement is configured to guide the refrigerant fluid and the gas through the first subcooler; and, when the gas to be liquefied and/or subcooled is the second gas, the refrigeration device is configured to provide the refrigerant fluid.

A small to mid-scale liquefied natural gas production system and method is provided. The disclosed liquefied natural gas production system employs a nitrogen-based refrigerant, at least one heat exchanger, three turbine/expanders and two or more refrigerant compression stages. The expansion ratio of one turbine/expander is appreciably lower than the expansion ratio of the other turbine/expanders such that the temperature of the exhaust stream from the turbine/expander with the lower expansion ratio is above the critical point temperature of the compressed natural gas containing feed stream but colder than -15° C.

A small to mid-scale liquefied natural gas production system and method is provided. The disclosed liquefied natural gas production system employs a nitrogen-based refrigerant, at least one heat exchanger, three turbine/expanders and two or more refrigerant compression stages. The expansion ratio of one turbine/expander is appreciably lower than the expansion ratio of the other turbine/expanders such that the temperature of the exhaust stream from the turbine/expander with the lower expansion ratio is above the critical point temperature of the compressed natural gas containing feed stream but colder than −15° C.

A small to mid-scale liquefied natural gas production system and method is provided. The disclosed liquefied natural gas production system employs a nitrogen-based refrigerant, at least one heat exchanger, three turbine/expanders and two or more refrigerant compression stages. The expansion ratio of one turbine/expander is appreciably lower than the expansion ratio of the other turbine/expanders such that the temperature of the exhaust stream from the turbine/expander with the lower expansion ratio is above the critical point temperature of the compressed natural gas feed stream but colder than −15° C.

An oxygen liquefier system may be configured to defrost an oxygen line included therein. The system may include one or more sieve beds, a liquid oxygen reservoir, an oxygen line, a controller, a heating apparatus, and/or other components. The one or more sieve beds are configured to extract oxygen from air obtained from an ambient environment. The liquid oxygen reservoir is configured to store oxygen extracted at the one or more sieve beds that has been liquefied. The oxygen line is configured to provide fluid communication between the one or more sieve beds and the liquid oxygen reservoir. The controller is configured to detect a blockage caused by frozen liquid within the oxygen line based on a liquid oxygen production rate. The heating apparatus is configured to defrost the oxygen line to melt frozen liquid within the oxygen line responsive to the detection of the blockage.

The invention relates to a liquefied gas storage facility, in particular for liquid hydrogen, comprising a liquefied gas tank intended to contain gas in liquid form and a gaseous phase, a device for cooling the contents of the tank, the cooling device comprising at least a first refrigerator with a cycle for refrigerating a cycle gas, said first refrigerator comprising, arranged in series in a cycle circuit: a member for compressing the cycle gas, a member for cooling the cycle gas, a member for expanding the second cycle gas and a member for reheating the expanded cycle gas, the cooling device comprising a first heat transfer fluid loop comprising a first end exchanging heat with a cold end of the first refrigerator and a second end comprising a first heat exchanger located in the tank, the first heat transfer fluid loop comprising a member for circulating the heat transfer fluid, characterized in that the first heat exchanger exchanges heat directly with the inside of the tank, that is to say that the first heat exchanger exchanges heat directly with the fluid which surrounds it in the tank.

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.

A process for producing liquefied natural gas and liquid carbon dioxide comprising: Step a): separating a natural gas feed gas into a CO.sub.2-enriched gas stream and a CO.sub.2-depleted natural gas stream; Step b): liquefying the CO.sub.2-depleted natural gas stream in a liquefaction unit comprising at least a main heat exchanger and a system for producing frigories, said liquefaction unit comprising at least one refrigeration cycle fed by a refrigerant stream; Step c): simultaneous liquefying of the CO.sub.2-enriched gas stream resulting from step a) in a CO.sub.2 liquefaction unit; wherein the refrigeration necessary for the liquefaction of the CO.sub.2-enriched gas stream and for the liquefaction of the natural gas is supplied by said frigorie-producing system of the liquefaction unit and in that the refrigeration necessary for the liquefaction of the CO.sub.2-enriched gas stream originates from a portion of said refrigerant stream supplying the refrigeration cycle of said liquefaction unit.

A process for producing liquefied natural gas (14) and liquid carbon dioxide (CO.sub.2) (15) comprising at least the following steps: Step a): separating a natural gas feed gas (1), containing hydrocarbons and carbon dioxide in a treatment unit (2), into a CO.sub.2-enriched gas stream (4) and a CO.sub.2-depleted natural gas stream (3); step b): liquefying the CO.sub.2-depleted natural gas stream (3) resulting from step a) in a natural gas liquefaction unit (5) comprising at least a main heat exchanger (8) and a system (9) for producing frigories; step c): simultaneous liquefying of the CO.sub.2-enriched gas stream (4) resulting from step a) in a CO.sub.2 liquefaction unit (6); characterized in that all of the refrigeration necessary for the liquefaction of the CO.sub.2-enriched gas stream (4) and for the liquefaction of the natural gas is supplied by said frigorie-producing system (9) of the natural gas liquefaction unit (5).