The amount of consumption of gas is reduced when the gas is expanded to be cooled by using a plurality of expansion turbines. A high-pressure expansion turbine includes: a gas supply passage through which bearing gas is supplied to a bearing portion; and a gas discharge passage through which the bearing gas which has been supplied from the gas supply passage to the bearing portion is discharged from the bearing portion. A low-pressure expansion turbine includes: a gas supply passage through which the bearing gas is supplied to a bearing portion; and a gas discharge passage through which the bearing gas which has been supplied from the gas supply passage to the bearing portion is discharged from the bearing portion. The bearing gas discharged from the gas discharge passage of the high-pressure expansion turbine is supplied to the gas supply passage of the low-pressure expansion turbine.

An arrangement comprising at least one liquefaction plant for liquefying a gaseous medium to produce a liquefied medium; and at least one storage tank for storing the liquefied medium. A first transfer line is provided which is connected between the liquefaction plant and the storage tank, for transferring liquefied medium from the liquefaction plant into the storage tank. A second transfer line is connected between the liquefaction plant and the storage tank, for transferring gaseous medium from the storage tank into the liquefaction plant. The second transfer line, which used for transferring medium from the storage tank into the liquefaction plant, is arranged so that it is routed at least partially through the area of the storage tank in which the liquefied medium is stored in use.

The invention relates to a method for low-temperature cooling/liquefaction of a working fluid, in particular a working fluid including helium or consisting of pure helium by means of a refrigerator/liquefier that includes a working circuit provided with a compressor station and a cold box. The refrigerator/liquefier subjects the working gas within the working circuit to a cycle that includes, in series: compressing the working fluid within the compressor station, cooling and decompressing the working fluid in the cold box, and heating the working fluid with a view to the return thereof to the compressor station. The compressor station includes one or more compression levels, each one using one or more compressors mounted on landings. The method is characterized in that the refrigerator includes a device for injecting a seal gas that is separate from the working fluid on at least one landing of the compressor(s) so as to form a gas seal that guides the working fluid leaks, coming from the working circuit, to an area for recirculating and returning the fluid into the working circuit.

A method of cooling a process stream with an auxiliary stream is described, wherein the exchange of heat between the process stream and the auxiliary stream is effected in a first heat exchanger and a second heat exchanger connected downstream thereof.

Plant and method for producing hydrogen at cryogenic temperature, comprising: an electrolyzer; a hydrogen circuit to be cooled, comprising an upstream end connected to the hydrogen outlet and a downstream end to he connected to a member for collecting cooled and/or liquefied hydrogen, the plant also comprising a set of heat exchanger(s) in heat exchange with the hydrogen circuit to be cooled, the plant comprising at least one cooling device in heat exchange with at least a portion of the set of heat exchanger(s), the plant further comprising an oxygen circuit comprising an upstream end connected to the oxygen outlet and a downstream end, the oxygen circuit comprising a system for expanding the oxygen stream and at least one heat exchange between the expanded oxygen stream and the hydrogen circuit to be cooled, characterized in that the oxygen circuit comprises at least one oxygen compressor arranged upstream of the oxygen stream expansion system, the oxygen stream expansion system comprising an expansion turbine and in that said expansion turbine and said compressor are coupled to the same rotating shaft to transfer expansion - work from the pressurized oxygen stream to the compressor in order to compress the oxygen stream upstream of the turbine.

Installation and method for storing and dispensing liquefied hydrogen involving a source of gaseous hydrogen, a liquefier, and two storage reservoirs for liquid hydrogen at determined respective storage pressures, wherein the liquefier includes an inlet connected to the source and an outlet connected in parallel, via a set of valves, to a respective inlet of each storage reservoir.

A method including, compressing a first hydrogen stream, and expanding a portion to produce a hydrogen refrigeration stream, cooling a second hydrogen stream thereby producing a cool hydrogen stream, wherein at least a portion of the refrigeration is provided by a nitrogen refrigeration stream, further cooling at least a portion of the cool hydrogen stream thereby producing a cold hydrogen stream, and a warm hydrogen refrigeration stream wherein at least a portion of the refrigeration is provided by the hydrogen refrigeration stream, compressing the warm hydrogen refrigeration stream, mixing the balance of the compressed first hydrogen stream with a high-pressure gaseous nitrogen stream to form an ammonia synthesis gas stream, and wherein the first hydrogen stream and the warm hydrogen refrigeration stream are compressed in the same compressor.

A method of liquefying hydrogen, including dividing a hydrogen stream into at least a first fraction and a second fraction, introducing the first fraction into a refrigeration cycle of a hydrogen liquefaction unit, thereby liquefying a product hydrogen stream, withdrawing one or more warm hydrogen stream(s) from the hydrogen liquefaction unit, and returning the one or more warm hydrogen stream to the hydrogen stream, wherein the second fraction is combined with a high-pressure nitrogen stream to form an ammonia synthesis gas stream.

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.

Disclosed is a small-scale hydrogen liquefaction system using cryocoolers. The system includes: a gas supply line to supply a gaseous hydrogen; n cryocoolers each connected to the gas supply line to be connected in parallel and configured such that the gaseous hydrogen supplied from the gas supply line is divided into n portions, and the n portions flow through the n cryocoolers, respectively, and are cooled to a liquefaction temperature, wherein n is a natural number equal to or greater than 2; n heat exchangers each attached to a cold head of each of the n cryocoolers; and a low-temperature chamber providing an accommodation space to accommodate the n cryocoolers therein.