The present invention relates to a refrigerant composition. According to the invention it is envisioned that the composition comprises comprising an inert gas selected from nitrogen, argon, neon and a mixture thereof, and a mixture of at least two C.sub.1-C.sub.5 hydrocarbons. The present invention further relates to the use of the refrigerant composition in a method for liquefying a gaseous substance, particularly hydrogen or helium.

The present invention relates to a refrigerant composition comprising neon and hydrogen. The present invention further relates to the use of the refrigerant composition in liquefying gaseous substances such as hydrogen or helium.

A system and method for liquefying a natural gas stream, including a liquefaction heat exchanger having at least three cooling bundles and arranged such that the natural gas stream passes sequentially therethrough. A first cooling bundle condenses heavy hydrocarbon components in the natural gas stream. A second cooling bundle liquefies the natural gas stream. A third cooling bundle sub-cools the LNG stream. A hydraulic turbine has an inlet operationally connected to an outlet of the second cooling bundle, and an outlet operationally connected to an inlet of the third cooling bundle. The hydraulic turbine cools the LNG stream and reduces the pressure of the LNG stream to form a reduced-pressure LNG stream.

Disclosed is a device for liquefying a fluid, comprising a circuit for fluid to be cooled, the device comprising a set of one or more heat exchangers exchanging heat with the circuit of fluid to be cooled, at least one first cooling system exchanging heat with at least some of the set of one or more heat exchangers, the first cooling system being a refrigerator with refrigeration cycle of a cycle gas mostly comprising helium, the refrigerator comprising, arranged in series in a cycle circuit: a cycle gas compression mechanism at least one cycle gas cooling member, a mechanism for expansion of the cycle gas and at least one expanded cycle gas heating member, wherein the compression mechanism comprises at least four compression stages in series, consisting of a set of one or more centrifuge-type compressors, the compression stages being mounted on shafts rotated by a set of one or more motors, the expansion mechanism comprising at least three expansion stages in series, consisting of a set of centripetal turbines, the at least one cycle gas cooling member being configured to cool the cycle gas at the outlet of at least one of the turbines and wherein at least one of the turbines is coupled to the same shaft as at least one compression stage so as to supply the compression stage with the mechanical work produced during the expansion.

Methods and systems for liquefying natural gas using environmentally-friendly low combustibility refrigerants are provided. Methods of liquefaction include cooling a fluid in an LNG facility via indirect heat exchange with an environmentally-friendly low combustibility refrigerants that are propane, ethane and methane mixed with small amounts of fluorinated olefin, but still within close proximity to the boiling points of the pure refrigerants such that the mixed refrigerants can still be used in an optimized cascade process.

Closed-loop refrigeration cycles for liquid oxygen densification are disclosed. The disclosed refrigeration cycles may be turbine-based refrigeration cycles or a Joule-Thompson (JT) expansion valve based refrigeration cycles and include a refrigerant or working fluid comprising a mixture of neon or helium together with nitrogen and/or oxygen.

A refrigerator according to the present invention includes: a cooling part for cooling an object to be cooled through heat exchange with a refrigerant; an expander-integrated compressor including a compressor for compressing the refrigerant and an expander for expanding the refrigerant integrated therein; and a refrigerant circulation line configured to circulate the refrigerant through the compressor, the expander, and the cooling part. The compressor includes a low-stage compressor, a middle-stage compressor, and a high-stage compressor disposed in series in the refrigerant circulation line. The expander-integrated compressor includes: the middle-stage compressor; an expander for adiabatically expanding and cooling the refrigerant discharged from the high-stage compressor; a first motor having an output shaft connected to the middle-stage compressor and to the expander; at least one non-contact type bearing, disposed between the middle-stage compressor and the expander, for supporting the output shaft of the first motor without being in contact with the output shaft; and a casing for housing the middle-stage compressor, the expander, and the at least one non-contact type bearing.

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.

An on-board aircraft nitrogen enriched air and cooling fluid generation system and method are disclosed. In one embodiment, the system includes a first heat exchanger which is configured to receive pressurized air from a source of pressurized air. Further, the first heat exchanger cools the pressurized air to a temperature in the range of 120 C. to 70 C. Furthermore, the system includes a separation unit is configured and dimensioned to communicate with the first heat exchanger. The separation unit generates nitrogen enriched air from the cooled air at the temperature range of 120 C. and 70 C.

A framed, low-temperature refrigeration device is provided, which includes a working circuit that forms a loop and contains a working fluid, the working circuit forming a cycle that includes in series: a compression mechanism, a cooling mechanism, an expansion mechanism and a heating mechanism, wherein the mechanisms for cooling and heating the working fluid include a common heat exchanger in which the working fluid flows in opposite directions in two separate transit portions of the working circuit. The device may also include a refrigeration heat exchanger for extracting heat from at least one member by exchanging heat with the working fluid flowing in the working circuit, wherein the compression mechanism includes two separate compressors, wherein the mechanism for cooling the working fluid includes two cooling heat exchangers which are arranged respectively at the outlet of the two compressors and ensure heat exchange between the working fluid and a cooling fluid, wherein the frame extends in a longitudinal direction and includes a lower base intended to be mounted on a support, the cooling heat exchangers are located in the frame about the common heat exchanger, i.e. the cooling heat exchangers are not located below the common heat exchanger between the common heat exchanger and the lower base of the frame.