Systems and methods for liquefying a gaseous hydrogen that include a first refrigeration stage and a second refrigeration stage. The first refrigeration stage includes a first heat exchanger configured to flow a first refrigerant to pre-cool the gaseous hydrogen. The second refrigeration stage includes a second heat exchanger configured to flow a second refrigerant to liquefy and sub-cool the hydrogen. The second refrigerant is split into two streams that flow through two compressor-expanders and multiple passes through the second heat exchanger before being recombined to repeat the second refrigeration stage circuit.

Systems and methods for liquefying a gaseous hydrogen that include a first refrigeration stage and a second refrigeration stage. The first refrigeration stage includes a first heat exchanger configured to flow a first refrigerant to pre-cool the gaseous hydrogen. The second refrigeration stage includes a second heat exchanger configured to flow a second refrigerant to liquefy and sub-cool the hydrogen. The second refrigerant is split into two streams that flow through two compressor-expanders and multiple passes through the second heat exchanger before being recombined to repeat the second refrigeration stage circuit.

An expansion turbine configured such that even when pressure of process gas steeply changes, the amount of process gas leaking from a gap between an impeller and a cover is made small. The expansion turbine includes a gas supply passage which is connected to any one of a gas supply passage and a gas discharge passage and through which gas is supplied to a region located between a rotor member and a casing member.

The present invention pertains to a method for filling a transport tank with a product medium in a liquid state in a gas liquefaction plant, comprising a step of supplying the product medium in the liquid state from a storage tank (18) of the gas liquefaction plant to the transport tank. The method is characterized in that it further comprises a step of discharging the product medium in a gaseous state from the transport tank into the storage tank (18).

A pre-cool refrigeration circuit includes a pre-cool compressor configured to receive and compress pre-cool refrigerant vapor from a pre-cool heat exchanger, a pre-cool cooling device configured to receive and cool compressed pre-cool refrigerant from the pre-cool compressor, a pre-cool expansion device configured to receive and expand compressed and cooled pre-cool refrigerant from the pre-cool cooling device, and a pre-cool separation device configured to receive expanded pre-cool refrigerant from the pre-cool expansion device at a reduced pressure so as to lower a boiling point of the expanded pre-cool refrigerant and to separate the expanded pre-cool refrigerant into a pre-cool refrigerant vapor stream and a pre-cool refrigerant liquid stream. A primary refrigeration circuit includes a first primary compressor configured to receive and compress a primary refrigerant vapor from a liquefier heat exchanger and the pre-cool heat exchanger, a primary cooling device configured to receive and cool compressed primary refrigerant from the first primary compressor. The primary cooling device is in fluid communication with the pre-cool heat exchanger and the liquefier heat exchanger. A first primary expansion device is configured to receive and expand compressed and cooled primary refrigerant from the liquefier heat exchanger, with the first primary expansion device having an outlet in fluid communication with the liquefier heat exchanger and the pre-cool heat exchanger.

In an aspect, a system comprises a water stream in fluid communication with an electrolyzer; the electrolyzer comprising an anode and a cathode side chamber; a deep space oxygen radiator in fluid communication with the anode side chamber of the electrolyzer; a cryogenic heat exchanger comprising an oxygen storage tank in fluid communication with the deep space oxygen radiator; an electrochemical hydrogen compressor in fluid communication with the cathode side chamber; a hydrogen storage tank in fluid communication with the electrochemical hydrogen compressor via a cooled hydrogen stream; wherein at least a portion of the cooled hydrogen stream is in a first fluid communication with an expansion valve and the cryogenic heat exchanger; wherein the hydrogen storage tank is in a second fluid communication with the electrochemical hydrogen compressor via a warmed hydrogen stream; and wherein the cryogenic heat exchanger is in fluid communication with the warmed hydrogen stream.

Plant and method for producing hydrogen at cryogenic temperature, in particular liquefied hydrogen, comprising: an electrolyzer having an oxygen outlet and a hydrogen outlet; a hydrogen circuit to be cooled, comprising an upstream end connected to the hydrogen outlet and a downstream end to be 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 further comprising at least one cooling device in heat exchange with at least a portion of the set of heat exchanger(s), the hydrogen circuit to be cooled comprising a system for expanding the hydrogen stream and at least one hydrogen compressor upstream of the hydrogen stream expansion system, the hydrogen stream expansion system comprising at least one expansion turbine, wherein said at least one expansion turbine and said at least one compressor are coupled to the same rotating shaft to transfer expansion work from the pressurized hydrogen stream to the compressor in order to compress the hydrogen stream upstream of the turbine.

The present invention relates to a method for liquefying hydrogen, the method comprises the steps of: cooling a feed gas stream comprising hydrogen with a pressure of at least 15 bar(a) to a temperature below the critical temperature of hydrogen in a first cooling step yielding a liquid product stream. According to the invention, the feed gas stream is cooled by a closed first cooling cycle with a high pressure first refrigerant stream comprising hydrogen, wherein the high pressure first refrigerant stream is separated into at least two partial streams, a first partial stream is expanded to low pressure, thereby producing cold to cool the precooled feed gas below the critical pressure of hydrogen, and compressed to a medium pressure, and wherein a second partial stream is expanded at least close to the medium pressure and guided into the medium pressure first partial stream.

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.

An expansion turbine configured such that even when pressure of process gas steeply changes, the amount of process gas leaking from a gap between an impeller and a cover is made small. The expansion turbine includes a gas supply passage which is connected to any one of a gas supply passage and a gas discharge passage and through which gas is supplied to a region located between a rotor member and a casing member.