Apparatus, systems, and methods store energy by liquefying a gas such as air, for example, and then recover the energy by regasifying the cryogenic liquid and combusting or otherwise reacting the gas with a fuel to drive a heat engine. Carbon may be captured from the heat engine exhaust by using the cryogenic liquid to freeze carbon dioxide out of the exhaust. The process of liquefying the gas may be powered with electric power from the grid, for example, and the heat engine may be used to generate electricity. Hence, in effect these apparatus, systems, and methods may provide for storing electric power from the grid and then subsequently delivering it back to the grid.

A method for liquefaction of natural gas using refrigeration from a combination of sources including a refrigeration cycle and letdown energy of natural gas is provided. The natural gas to be liquefied (LNG) is boosted in pressure using a booster that is powered by expansion of a portion of the natural gas flow from the booster through a first natural gas turbine. A second flow of natural gas is expanded in a second natural gas turbine, and the resulting expanded stream, along with the natural gas expanded in the first natural gas turbine, are warmed against the natural gas to be liquefied. The flow rate of the natural gas in the second natural gas turbine is decoupled from the booster, thereby allowing for variation in flow rates and pressures while maintaining a constant production of LNG.

An integrated fuel combustion system with adsorptive gas separation separates a portion of carbon dioxide from a combustion gas mixture and provides for recycle of separated carbon dioxide to the intake of the fuel combustor for combustion. A process for carbon dioxide separation and recycle includes: admitting combustion gas to an adsorptive gas separation system contactor containing adsorbent material; adsorbing a portion of carbon dioxide; recovering a first product gas depleted in carbon dioxide for release or use; desorbing carbon dioxide from the adsorbent material and recovering a desorbed second product gas enriched in carbon dioxide for sequestration or use; admitting a conditioning fluid into the contactor and desorbing a second portion of carbon dioxide to recover a carbon dioxide enriched conditioning stream; and recycling a portion of the carbon dioxide enriched conditioning stream to an inlet of fuel combustor to pass through the fuel combustor for combustion.

A method of purifying air via a pre-purification unit (PPU) of an air separation unit (ASU) system having a pre-PPU chiller that is upstream of the PPU to cool compressed air before the compressed air is fed to the PPU can include passing air through an adsorber of the PPU to pass the air through a bed of adsorbent material within a vessel of the adsorber. In response to the pre-PPU chiller being determined to have an issue resulting in the pre-PPU chiller being tripped or requiring the pre-PPU chiller to be taken off-line, continuing to operate the ASU system at a full capacity even though nitrous oxide (N2O) within the air output from the PPU exceeds a first pre-selected threshold and is below a second pre-selected threshold associated with carbon dioxide (CO2) breakthrough. An ASU and a PPU can be designed to implement an embodiment of the method.

A system and method for separating air in an air separation plant is provided. The disclosed systems and methods divert a portion of the compressed, purified air stream to a bypass system configured to selectively produce a higher pressure compressed output stream or a lower pressure compressed output stream. The higher pressure and/or lower pressure compressed output streams are cooled in a main heat exchanger by indirect heat transfer with a plurality of product streams from the air separation plant and then rectified in the distillation column system. A second portion of the compressed, purified air stream is partially cooled in the main heat exchanger and expanding in a turbo-expander to produce power and an exhaust stream which is directed to the distillation column system of the air separation plant where it imparts additional refrigeration generated by the expansion of the compressed air stream in the turbo-expander.

Liquefaction systems and associated processes and methods are disclosed herein. Liquefaction systems in accordance with the present technology can include a liquefier positioned to liquefy gases from an emission stream. The liquefier can include a compressor configured to compress a first gas to produce a first liquid, and to compress a second gas to produce a second liquid. The first liquid can be directed to a first collection tank and the second liquid can be directed to a second collection tank. In some embodiments, a liquefaction system can direct a portion of a compressed liquid to a liquefier to pre-cool gases in the emission stream and/or to cool gases at various stages of compression.

An on-board aircraft nitrogen enriched air and cooling fluid generation system and method are disclosed. In one embodiment, the system includes a first heat exchanger which is configured to receive pressurized air from a source of pressurized air. Further, the first heat exchanger cools the pressurized air to a temperature in the range of 120 C. to 70 C. Furthermore, the system includes a separation unit is configured and dimensioned to communicate with the first heat exchanger. The separation unit generates nitrogen enriched air from the cooled air at the temperature range of 120 C. and 70 C.

A system and method for separating air in an air separation plant is provided. The disclosed systems and methods divert a portion of the compressed, purified air stream to a bypass system configured to selectively produce a higher pressure compressed output stream or a lower pressure compressed output stream. The higher pressure and/or lower pressure compressed output streams are cooled in a main heat exchanger by indirect heat transfer with a plurality of product streams from the air separation plant and then rectified in the distillation column system. A second portion of the compressed, purified air stream is partially cooled in the main heat exchanger and expanding in a turbo-expander to produce power and an exhaust stream which is directed to the distillation column system of the air separation plant where it imparts additional refrigeration generated by the expansion of the compressed air stream in the turbo-expander.

The invention relates to a method for cooling, purifying and separating a gaseous mixture containing at least one impurity, in which the gaseous mixture is cooled to a temperature no higher than the temperature at which the at least one impurity solidifies in a heat exchanger having cooling passages, the cooling passages being at least partially covered with a coating and/or physically treated and/or chemically treated, the coating and/or the treatment serving to limit or even prevent the solidified impurity from forming and/or adhering to a surface of the passages; at least one portion of the solidified impurity exiting the cooling passages of the heat exchanger is collected; and the gaseous mixture is withdrawn from the heat exchanger.

A method and apparatus for separating air in which production of the liquid products can be selectively varied between high and low production rates by varying the pressure ratio across a turboexpander used in imparting refrigeration with the use of a branched flow path. The branched flow path has a system of valves to selectively and gradually introduce a compressed refrigerant air stream into either a booster compressor branch having a booster compressor to increase the pressure ratio during high modes of liquid production or a bypass branch that bypasses the booster compressor to decrease the pressure ratio during low modes of liquid production. A recycle branch is connected to the booster compressor branch to allow compressed air to be independently recycled from the outlet to the inlet of the booster compressor during turndown from the high to the low liquid mode of liquid production to prevent surge.