A method for the production of liquefied natural gas (LNG) and nitrogen is provided. The method may include the steps of: a) providing a nitrogen production facility, wherein nitrogen production facility comprises: a main heat exchanger, an air separation unit, a nitrogen recycle compressor, a first nitrogen refrigeration supply configured to provide refrigeration to the main heat exchanger for cooling a main air feed, b) providing a secondary refrigeration supply; c) liquefying a natural gas stream using refrigeration from the secondary refrigeration supply to form an LNG product stream; wherein the secondary refrigeration supply is configured to compress and expand a refrigerant to produce refrigeration, wherein the refrigerant of the secondary refrigeration supply is shared with refrigerant of the first nitrogen refrigeration supply

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 power recovery sub-system for a cryogenic energy storage system, the sub-system comprising: a first and a second thermal energy storage device (TESD); a first, a second and a fourth heat exchanger (HEX); a first, a second and a fourth expansion stage; a first arrangement of conduits, having an upstream end and a downstream end, and configured to pass a working fluid through the first HEX, the first expansion stage, the second HEX, and the second expansion stage; a second arrangement of conduits configured to pass a first heat transfer fluid from the first TESD, through the first and the second HEX; and a third arrangement of conduits configured to pass a second heat transfer fluid from the second TESD, through the fourth HEX, wherein the first arrangement of conduits is configured to pass the working fluid through the fourth HEX and the fourth expansion stage.

The invention relates to an installation for producing liquefied hydrogen having a gaseous hydrogen generator configured to produce gaseous hydrogen, a liquefier, a supply duct connecting a gaseous hydrogen outlet of the gaseous hydrogen generator to an inlet of the liquefier, the liquefier having a refrigerator having a cycle circuit configured to provide cooling power and cool the gaseous hydrogen from the supply duct with a view to the liquefaction thereof, the installation having at least one compressor for the gaseous hydrogen produced by the gaseous hydrogen generator and a buffer store configured to store the compressed gaseous hydrogen between the gaseous hydrogen generator and the liquefier, the buffer store being connected to the supply duct via a set of bypass duct(s), i.e. the buffer store and the liquefier are connected in parallel to the gaseous hydrogen outlet of the gaseous hydrogen generator.

Described herein are methods and systems for removing natural gas liquids from a natural gas feed stream and for liquefying the natural gas feed stream so as to produce a liquefied natural gas (LNG) stream and a natural gas liquids (NGL) stream.

A method for reliquefying and returning boil-off gas (BOG) to a liquefied natural gas (LNG) tank, having the steps of: compressing a BOG taken from the headspace of an LNG tank to a pressure p.sub.high, cooling the compressed gas to a temperature T.sub.1, such as by water cooling; expanding at least part of the gas from step c) to a pressure p.sub.expand; cooling the gas expanded in step d), such as by a heat exchanger in counterflow with cooling BOG (F2) from the head space of the LNG tank 3 to a temperature T.sub.4; returning the gas from step e) to the LNG tank; wherein the pressure p.sub.high is at least 200 bar, and wherein the pressure p.sub.expand is 80 to 180 bar.

The present invention relates to an apparatus for transferring a fluid, particularly CO.sub.2, from a subcritical gaseous state into a supercritical state, the apparatus comprising a compressor unit, a pump unit, a drive unit and a liquefaction unit, wherein the compressor unit and the pump unit are commonly driven by the drive unit, and wherein the liquefaction unit is provided downstream of the compressor unit and upstream of the pump unit, wherein the compressor unit is configured to compress the fluid from a first subcritical gaseous state to a first predetermined pressure level of a second subcritical gaseous state, wherein the liquefaction unit is configured to reduce the temperature of the compressed fluid in the second subcritical state downstream of the compressor unit to a predetermined temperature level such that the fluid is transferred from the second subcritical gaseous state to a liquid state.

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 liquefier device which may be a retrofit to an air separation plant or utilized as part of a new design. The flow needed for the liquefier comes from an air separation plant running in a maxim oxygen state, in a stable mode. The three gas flows are low pressure oxygen, low pressure nitrogen, and higher pressure nitrogen. All of the flows are found on the side of the main heat exchanger with a temperature of about 37 degrees Fahrenheit. All of the gases put into the liquefier come out as a subcooled liquid, for storage or return to the air separation plant. This new liquefier does not include a front end electrical compressor, and will take a self-produced liquid nitrogen, pump it up to a runnable 420 PSIG pressure, and with the use of turbines, condensers, flash pots, and multi pass heat exchangers. The liquefier will make liquid from a planned amount of any pure gas oxygen or nitrogen an air separation plant can produce.