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.

A hydrogen boil-off gas recovery method, comprises liquefying hydrogen by cooling a hydrogen feed stream in a first cryogenic cold box, further cooling the hydrogen in a second cryogenic cold box, liquefying the hydrogen in the second cryogenic cold box or downstream thereof, providing liquefied hydrogen a loading bay containing at least one hydrogen transport truck, sending boil-off gas from at least one hydrogen transport truck in the loading bay to which liquefied hydrogen has been provided to an indirect heat exchanger outside the first and second cryogenic cold boxes in order to warm the boil-off gas and mixing at least part of the warmed boil-off gas with the hydrogen feed stream upstream of the first cryogenic cold box or with hydrogen in a hydrogen refrigeration cycle used to provide refrigeration for the second cryogenic cold box as a function of the pressure of the boil-off gas.

A centrifugal compressor, the capacity of which can be increased with keeping the diameter of the impeller at minimum, is provided. The centrifugal compressor includes: a drive gear (11); a drive shaft (3) protruding from one side of the drive gear (11) in a central axis direction of the drive gear (11); a no. 1 driven pinion gear (12) configured for rotation of the drive gear (11) to be transmitted thereto; a no. 1 driven pinion shaft (5) protruding from both sides of the no. 1 driven pinion gear (12) in a central axis direction of the no. 1 driven pinion gear (12); and a couple of first stage compressor sections (7a, 7b), each of which is provided in each end of the no. 1 driven pinion shaft (5) and is configured to compress fluid by rotation of the no. 1 driven pinion shaft (5).

A mixed phase pressurized unstabilized hydrocarbon stream is fed into a stabilizer column at a feed pressure. A liquid phase of stabilized hydrocarbon condensate is discharged from a bottom end of the stabilizer column, while a vapour phase of volatile components from the pressurized unstabilized hydrocarbon condensate stream is discharged from a top end of the stabilizer column. The vapour phase being discharged from the top end of the stabilizer column is compressed and subsequently passed through an ambient heat exchanger wherein partial condensation takes place. The resulting partially condensed overhead stream is separated in an overhead separator into a vapour effluent stream and an overhead liquid stream. After discharging the overhead liquid stream from the overhead separator, it is selectively divided into a liquid reflux stream and a liquid effluent stream. The liquid reflux stream is expanded to the feed pressure and fed into the stabilizer column.

A method of producing liquefied natural gas (LNG) is disclosed. A natural gas stream is provided from a supply of natural gas. The natural gas stream is compressed in at least two serially arranged compressors to a pressure of at least 2,000 psia to form a compressed natural gas stream. The compressed natural gas stream is cooled to form a cooled compressed natural gas stream. The cooled compressed natural gas stream is expanded in at least one work producing natural gas expander to a pressure that is less than 3,000 psia and no greater than the pressure to which the at least two serially arranged compressors compress the natural gas stream, to thereby form a chilled natural gas stream. The chilled natural gas stream is liquefied.

A liquefier includes a Dewar having a storage portion and a neck portion extending therefrom. A hermetically isolated liquefaction chamber is disposed within the neck of the Dewar. One or more control components including a temperature and pressure sensor are coupled to a CPU and disposed within the liquefaction chamber for dynamic control of liquefaction conditions. A gas flow control is coupled to the CPU for regulating an input gas flow into the liquefaction chamber. A volume surrounding the liquefaction chamber may be adapted to provide a counter-flow heat exchange. These and other features provide improved liquefaction efficiency among other benefits.

A highly efficient refrigeration system and process for precooling/liquefaction of a hydrogen feed stream and method of turndown of such system is disclosed. The disclosed refrigeration system and associated methods employ a reverse Brayton refrigeration cycle using a nitrogen based refrigerant and a fully integrated three pinion bridge (BriM) machine operatively coupling at least two turbine/expanders and at least four nitrogen refrigerant compression stages. Turndown of the hydrogen precooling and liquefaction process requires removal of nitrogen refrigerant from the refrigeration recycle loop by retaining liquid nitrogen in the phase separator, which is sized to accommodate the bulk of the nitrogen refrigerant used in the refrigeration circuit.

The method according to the invention comprises the separation of a feed stream (16) into a first fraction (60) and a second fraction (62) and the injection of at least part of the second fraction (62) into a second dynamic expansion turbine (46) to form a second expanded fraction (80). It comprises the cooling of the second expanded fraction (80) through heat exchange with at least part of the first headstream (84) coming from a first column (28) and the formation of a second feed stream (82) of the first column (28) from the second cooled expanded fraction.

Contemplated plants for flexible ethane recovery and rejection by allowing to switch the top reflux to the demethanizer from residue gas to the deethanizer overhead product and by controlling the flow ratio of feed gas to two different feed gas exchangers. Moreover, the pressure of the demethanizer is adjusted relative to the deethanizer pressure for control of the ethane recovery and rejection.

An apparatus for separating air by cryogenic distillation comprises N air compressors (C1, C2, C3) connected so as to receive air at ambient pressure and designed to produce air at a first pressure above 12 bar absolute, N being at least 3, each of the compressors being driven by a single asynchronous motor (M1, M2, M3), the total power of the compressors being at least 10 MW.