A method describing the integration of a nitrogen liquefier and letdown of natural gas for the production of liquid nitrogen and lower pressure natural gas is provided. The method may include: providing a nitrogen liquefier having a nitrogen refrigeration cycle, wherein the nitrogen liquefier comprises a nitrogen compressor, a nitrogen recycle compressor, a heat exchanger, and at least a first turbine booster and introducing a nitrogen gas stream to the nitrogen liquefier under conditions effective for liquefying the nitrogen to produce a liquid nitrogen product. The refrigeration needed to liquefy the nitrogen is provided for by the nitrogen refrigeration cycle and letdown of a high pressure natural gas stream.

A method for the integration of a nitrogen liquefier and liquefaction of natural gas for the production of liquefied natural gas and liquid nitrogen is provided. The method may include providing a nitrogen liquefaction unit and providing a natural gas liquefaction unit. Liquefaction of the nitrogen can be achieved via a nitrogen refrigeration cycle within the nitrogen liquefaction unit. Liquefaction of the natural gas can be achieved through the use of natural gas letdown and a second nitrogen refrigeration cycle. The two liquefaction units can be integrated via a common nitrogen recycle compressor, thereby providing significant capital savings.

A method and installation for storing and recovering energy, according to which a condensed air product is formed in an energy storage period, and in an energy recovery period, a pressure flow is formed and is expanded to produce energy using at least part of the condensed air product. For the formation of the condensed air product: the compression of air in an air conditioning unit, at least by means of at least one isothermally operated compressor device and the adsorptive cleaning of the air by means of at least one adsorptive cleaning device at a hyperbaric pressure level.

A heat exchanger apparatus can be configured so that there is at least one U or C shape configured manifold in combination with at least one Z or S shape configured manifold for the heat exchanger apparatus for the input and output of fluid into and out of the heat exchangers of the heat exchanger apparatus. In some embodiments, downstream and/or upstream lines can be connected to the manifolds at a center or off-center point for conveying inlet fluid and outlet fluid. A method of retrofitting a pre-existing plant, building a new plant, or designing a new plant that utilizes an embodiment of the heat exchanger apparatus can help provide an improved heat exchanger arrangement without significantly increasing the footprint needed for the arrangement so that a plant can be improved with an embodiment of the apparatus without requiring an enlarged footprint for the plant.

Described herein are systems and processes to produce liquefied nitrogen (LIN) using liquefied natural gas (LNG) as the refrigerant. The LIN may be produced by indirect heat exchange of at least one nitrogen gas stream with at least two LNG streams within at least one heat exchanger where the LNG streams are at different pressures.

A method for producing liquefied natural gas (LNG) is provided. The method may include feeding natural gas from a high-pressure natural gas source to a separator and removing a non-hydrocarbon from the natural gas. A portion of the natural gas from the separator may be precooled, and the precooled natural gas may be cooled in a first heat exchanger with a first refrigeration stream. A first portion of the cooled natural gas may be expanded in a turbo-expander to generate the first refrigeration stream. A second portion of the cooled natural gas may be cooled in a second heat exchanger with the first refrigeration stream and expanded in an expansion valve to produce a two-phase fluid containing the LNG and a vapor phase. The LNG may be separated from the vapor phase in a liquid separator and stored in a storage tank.

Described herein are methods and systems for liquefying natural gas by: cooling and liquefying a natural gas feed stream via indirect heat exchange with at least a first cold refrigerant stream to form a first liquefied natural gas stream and a warmed gaseous refrigerant stream; flashing and separating the first liquefied natural gas stream to form a liquefied natural gas product stream and at least a first flash gas stream; combining and compressing the first flash gas stream and the warmed gaseous refrigerant stream to form a compressed refrigerant stream; and expanding at least a first portion of the compressed refrigerant stream to form the first cold refrigerant stream; wherein the natural gas feed stream is kept separate from and is not combined with either the first flash gas stream or the compressed refrigerant stream.

A system for supplying gas to at least one gas-consuming appliance equipping a ship, the supply system includes at least one gas supply line for supplying gas to the at least one gas consuming appliance, the gas supply line being configured to be traversed by gas taken in the liquid state from a tank and subjected to a pressure lower than a pressure of the gas in a headspace of the tank, a first compression member configured to compress the gas from the gas supply line for supplying gas to the at least one gas-consuming appliance, a second compression member, characterized in that the first compression member and the second compression member alternately compress gas in the gaseous state from the gas supply line and gas taken in the gaseous state from the headspace of the tank.

The present invention discloses a hydrogen or helium throttling liquefaction system using direct current (DC) flow from the cold and hot ends of the regenerative cryocoolers, which belongs to the technical field of refrigeration and cryogenics. It includes a regenerative cryocooler module, a hot-end DC flow module, a cold-end DC flow module, a throttling liquefaction module, and a gas-phase circulation module. The modules are interconnected to form a closed loop for the flow of hydrogen or helium working fluid. DC flow is introduced from the cold and hot ends of the regenerative cryocooler through the DC flow pipelines and DC flow valves. The hot-end DC flow exchanges heat with the reflowing low-temperature working fluid and is cooled down. After that, it mixes with the cold-end DC flow and enters the throttling liquefaction module to generate liquid phase through throttling and liquefaction. After the liquid phase has output cooling capacity, it flows through the gas-phase circulation module and then enters the back-pressure chamber of the compressor to complete the cycle. Compared with the existing small-scale hydrogen and helium liquefaction technology using regenerative cryocoolers, the present invention has the advantages of simple structure, easy installation, high heat transfer efficiency and liquefaction efficiency of the system.

A system for supplying gas to at least one gas-consuming appliance equipping a ship, the supply system includes at least one gas supply line for supplying gas to the at least one gas consuming appliance, the gas supply line being configured to be traversed by gas taken in the liquid state from a tank and subjected to a pressure lower than a pressure of the gas in a headspace of the tank, a first compression member configured to compress the gas from the gas supply line for supplying gas to the at least one gas-consuming appliance, a second compression member, characterized in that the first compression member and the second compression member alternately compress gas in the gaseous state from the gas supply line and gas taken in the gaseous state from the headspace of the tank.