A refrigeration system for condensation of carbon dioxide (CO.sub.2) in a flue gas stream, the system includes a refrigeration circuit, a flue gas treatment system that includes a flue gas compressor, a flue gas adsorption drier, and a refrigeration system for condensation of CO.sub.2; and a method for condensation of CO.sub.2 in a flue gas stream using a circulating stream of an external refrigerant.

Exhaust gas from which impurities have been removed through pressurization and cooling by a compressor-based impurity separation mechanism is further cooled by a refrigerator-type heat exchanger. Drain produced from the cooling by the refrigerator-type heat exchanger is discharged and supplied as an alkalinity control agent to at least upstream of an aftercooler in a first impurity separator.

A system and method for power generation and CO.sub.2 sequestration include a fuel cell system configured to generate power using natural gas (NG), a container configured to store liquid natural gas (LNG), and a fluid processor configured to convert LNG received from the container into NG and to convert exhaust output from the fuel cell system to dry ice by transferring heat between and the LNG and the exhaust.

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.

According to certain embodiments of the invention, a gas containing at least 50% of carbon dioxide is cooled in a first exchanger so as to produce a cooled fluid, a liquid derived from the cooled fluid is sent to a distillation column to be separated therein, a head gas is withdrawn from the distillation column and reheated in the first exchanger, a vat liquid, which is richer in carbon dioxide than the gas containing at least 50% of carbon dioxide, is withdrawn and at least a portion thereof is heated in the first exchanger, at least a first portion of the vat liquid is vaporized in the first exchanger in order to produce a vaporized portion, the vaporized portion is sent back to the column and an NOx removal column is supplied with the liquefied cycle gas produced by vaporizing and reliquefying the vat liquid from the column.

In a process for the separation of a stream containing carbon dioxide, water and at least one light impurity including a separation step at subambient temperature, the feed stream is compressed in a compressor comprising at least two stages to form a compressed feed stream, the compressed feed stream is purified in an adsorption unit to remove water and form a dried compressed stream, the dried compressed stream or a stream derived therefrom is cooled to a subambient temperature and separated by partial condensation and/or distillation in a separation apparatus, liquid enriched in carbon dioxide is removed from the separation apparatus, the adsorption unit is regenerated using a regeneration gas and the regeneration gas is formed by separating, by permeation in a permeation unit, the dried compressed stream or a gas derived therefrom, the permeate of the permeation unit constituting the regeneration gas.

A method for capturing carbon dioxide from a flue gas includes (i) removing moisture from a flue gas to yield a dried flue gas; (ii) compressing the dried flue gas to yield a compressed gas stream; (iii) reducing the temperature of the compressed gas stream to a temperature T.sub.1 using a first heat exchanger; (iv) reducing the temperature of the compressed gas stream to a second temperarature T.sub.2 using a second heat exchanger stream, where T.sub.2<T.sub.1 and at least a portion of the carbon dioxide from the compressed gas stream condenses, thereby yielding a solid or liquid condensed-phase carbon dioxide component and a light-gas component; (v) separating purities the condensed-phase component from the light-gas component to produce a condensed-phase stream and a light-gas stream; and (vi) using at least a portion of the condensed-phase stream and/or the light-gas stream in the second heat exchanger.

Systems for separating CO.sub.2 from a flue gas source are provided. The systems can include a liquefaction component operatively coupled to the separation component and comprising a recuperative heat exchanger configured to receive the separated CO.sub.2 from the separation component and reduce the temperature of the separated CO.sub.2 by exchanging the heat of the separated CO.sub.2 with CO.sub.2 vapor generated by the liquefaction component and/or a storage component operatively coupled to the liquefaction component and configured to receive liquid CO.sub.2 from the liquefaction component. Methods for separating CO.sub.2 from a flue gas source are provided. The methods can include liquefying the CO.sub.2 stream to form both CO.sub.2 liquid and CO.sub.2 vapor; and using at least a portion of the CO.sub.2 vapor to form the CO.sub.2 liquid during the liquefying.

A carbon dioxide separation and recovery system includes an exhaust gas sensible heat recovery part which recovers sensible heat of exhaust gas and generates electric energy by using the sensible heat of the recovered exhaust gas; a moisture removal part which is connected to the exhaust gas sensible heat recovery part and removes moisture contained in the sensible heat recovery exhaust gas from which the sensible heat is recovered by using the electric energy generated in the exhaust gas sensible heat recovery part; and a separation part which is connected to the moisture removal part to receive the sensible heat recovery exhaust gas from which moisture is removed by the moisture removal part, and separates solid carbon dioxide from the sensible heat recovery exhaust gas from which moisture is removed.

Processes and apparatuses for recovering a high purity carbon dioxide stream. A first separation zone that may include a cryogenic fractionation column provides the high-purity CO.sub.2 stream. A vapor stream from the cryogenic fractionation column is passed to a second separation zone to separate the CO.sub.2 from the other components. The second separation zone may include a pressure swing adsorption unit or a solvent separation unit. The second separation zone provides a hydrogen enriched gas stream that may be used in a gas turbine. The second stream from the second separation zone includes carbon dioxide and, after a pressure increase in a compressor, may be recycled to the first separation zone.