A system and method of gas liquefaction having a compression sequence for a mixed refrigerant in which a mixing column is used to provide liquid and vapor product streams at least one step of the compression sequence in which a phase separation is desirable. In addition, the compression sequence may optionally or alternatively use a stripper column in at least one step in the compression sequence in which a phase separation is desirable.

Cryogenic energy storage systems, and particularly methods for capturing cold energy and re-using that captured cold energy, are disclosed. The systems allow cold thermal energy from the power recovery process of a cryogenic energy storage system to be captured effectively, to be stored, and to be effectively utilized. The captured cold energy could be reused in any co-located process, for example to enhance the efficiency of production of the cryogen, to enhance the efficiency of production of liquid natural gas, and/or to provide refrigeration. The systems are such that the cold energy can be stored at very low pressures, cold energy can be recovered from various components of the system, and/or cold energy can be stored in more than one thermal store.

A method for producing liquefied natural gas (LNG). A natural gas stream is directed to a mechanical refrigeration unit to liquefy the natural gas stream and form a pressurized liquefied natural gas (LNG) stream with a pressure greater than 50 psia (345 kPa) and less than 500 psia (3445 kPa). A liquid refrigerant subcooling unit is provided at a first location. Liquid refrigerant is produced at a second location that is geographically separate from the first location. The produced liquid refrigerant is transported to the first location. The pressurized LNG stream is subcooled in the liquid refrigerant subcooling unit by exchanging heat between the pressurized LNG stream and at least one stream of the liquid refrigerant to thereby produce an LNG stream.

A method for separating nitrogen from an LNG stream with a nitrogen concentration of greater than 1 mol %. A pressurized LNG stream is produced at a liquefaction facility by liquefying natural gas, where the pressurized LNG stream has a nitrogen concentration of greater than 1 mol %. At least one liquid nitrogen (LIN) stream is received from storage tanks, the at least one LIN stream being produced at a different geographic location from the LNG facility. The pressurized LNG stream is separated in a separation vessel into a vapor stream and a liquid stream. The vapor stream has a nitrogen concentration greater than the nitrogen concentration of the pressurized LNG stream. The liquid stream has a nitrogen concentration less than the nitrogen concentration of the pressurized LNG stream. At least one of the one or more LIN streams is directed to the separation vessel.

A method for energy storage and recovery is based on the liquid air energy storage (LAES) operated at the pressure relationship such that the pressure of discharge air is greater than the charge air to provide a high round-trip efficiency. External cold source and cold thermal energy storage are used in a LAES to achieve a decrease in the LAES capital costs. A demand for a supplemental cold energy provided by external sources may be minimized. These features alone or in combination may result in reduced power demand required for cooling.

A method and device for generating electrical energy in a combined system of power plant, cold storage system and air compression system. The air compression system has a primary air compressor for generating a primary compressed air flow at a first pressure level. The power plant has a combustion unit which operates at a second pressure level and generates a combustion gas from which electrical energy is generated. The cold storage system has means for generating cold from compressed air, means for storing cold thus produced and means for generating a compressed air flow at the second pressure level using the stored cold. In a first operating mode (charging mode), a first compressed air flow is introduced from the air compression system into the cold storage system to charge the cold reservoir. In a second operating mode (discharging mode), the first compressed air flow generated in the primary air compressor, is introduced into the cold storage system to discharge the cold reservoir and to generate a third compressed air flow at the second pressure level, which is introduced into the combustion unit. The air compression system has a first booster for boosting compressed air compressed in the primary air compressor to the second pressure level. In a third operating mode (normal mode), the entire primary compressed air flow generated in the primary air compressor is boosted in the first booster to the second compressed air level and introduced into the combustion unit.

The invention relates to a method for storing and recovering energy, wherein an air liquefaction product (LAIR) is formed during an energy storage period, and a fluid pressure flow (12) is formed during an energy recovery period using at least one part of the air liquefaction product (LAIR) and is expanded for operation in at least one energy recovery device (14, 17). The air liquefaction product (LAIR) is obtained as a liquid medium during the energy storage period by compressing air in an air conditioning device (3), said compression being operated while supplying energy, in particular while supplying a current (9), optionally stored in a cold state, and fed to an evaporator unit (7). The air liquefaction product (LAIR) is expanded for operation as a fluid pressure flow (12) in the at least one energy recovery device (14, 17) during the energy recovery period after a pressure increase. The aim of the invention is to provide a solution with which even existing gas and steam power plants or open gas turbines are to be equipped with an energy storage capability. This is achieved in that the fluid pressure flow (12), in particular an air flow, is expanded in a first energy recovery device (14) and conducted through a recuperator device (13), in particular a heat boiler, upstream of said first energy recovery device (14), and thermal energy which has been decoupled from a flue gas flow (23) fed to the recuperator device (13) is coupled into the fluid pressure flow (12) in said heating tank. The flue gas flow (23) is fed to the recuperator device (13) from a fuel-fired second energy recovery device (17), in particular a gas turbine.

A method for the production of liquefied natural gas is provided. The method may include providing a high pressure natural gas stream, splitting the high pressure natural gas stream into a first portion and a second portion, and liquefying the first portion of the high pressure natural gas stream to produce an LNG stream. The refrigeration needed for cooling and liquefaction of the natural gas can be provided by a closed nitrogen refrigeration cycle and letdown of the second portion of the high pressure natural gas stream.

A method for the production of liquefied natural gas and liquid nitrogen is provided. The method may include providing a high pressure natural gas stream, splitting the high pressure natural gas stream into a first portion and a second portion, and liquefying the first portion of the high pressure natural gas stream to produce an LNG stream. The refrigeration needed for cooling and liquefaction of the natural gas and liquefaction of the nitrogen can be provided by a nitrogen refrigeration cycle and letdown of the second portion of the high pressure natural gas stream.

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