Methods and systems of the current invention separate condensable vapors such as carbon dioxide from light gases or liquids in a mixed process stream. The separation is carried out in a cryogenic process using one or more external cooling loops (ECLs) that first cool down a mixed process stream containing condensable vapors and light gases or liquids, causing the condensable vapors to desublimate and form solids. Next, the solids are separated from the light gases or liquids, forming a solid stream and a light gas or liquid stream. Then the refrigerants of the ECL are cooled by warming the separated solid stream and light gas or liquid stream, efficiently recovering energy used in cooling and desublimating the condensable vapors.

A cryogenic technology for the cost-efficient capture of each known component of emissions, such as carbon dioxide, sulfur oxides, nitrogen oxides, carbon monoxide, any other acid vapor, mercury, steam, in a liquefied or frozen/solidified form, and unreacted nitrogen (gas) from industrial plants, such that each of the components is captured separately with minimum use of energy and is industrially useful.

A method and apparatus for recovering carbon dioxide (CO2) from an oxyfuel combustion engine exhaust stream is described. The method comprises: providing and separating an oxyfuel combustion engine exhaust stream to provide a first liquefied CO2 stream and a first waste gas stream; condensing at least a portion of the first waste gas stream to provide a partly condensed waste gas stream; and separating the condensed waste gas stream to provide a second waste gas stream, and a second liquefied CO2 stream.

A thermoacoustic refrigerator includes at least one pair of pulse combustion tubes (10), preferably Rijke tubes, each tube (10) having a pair of spaced-apart Stirling engines (12), coupled together but with no separating membrane therebetween.

A method for the separation of liquid CO.sub.2 from a 2 phase feed stream, the process comprising the steps of: cooling the feed stream to a cryogenic temperature; expanding the cooled stream so as to further lower the temperature of the feed through expansion; mechanically separating the expanded stream, using a mechanical separator, into a gas phase and a liquid CO.sub.2 phase, and; venting the gas phase and outflowing the liquid CO.sub.2.

An apparatus for the separation of a flow containing carbon dioxide by distillation comprising a heat exchange means, a distillation column, means for sending the flow to be cooled in the heat exchange means down to a first intermediate temperature in order to form a liquid flow at a first temperature and at a first pressure, means for dividing the liquid flow in order to form a first fraction and a second fraction, means for expanding the first fraction to the pressure of a distillation column, means for sending the expanded first fraction to an intermediate level of the distillation column, means for exiting the second fraction from the cold end of the heat exchange means after cooling, means for expanding the cooled second fraction to the pressure of the distillation column, means for sending the second fraction to the distillation column and means for the withdrawal, from the bottom of the column, of a liquid flow.

A carbon dioxide capture system includes a first heat exchanger configured to exchange heat between an exhaust stream and a lean carbon dioxide effluent stream. The carbon dioxide capture system also includes a first turboexpander including a first compressor driven by a first turbine. The first compressor is coupled in flow communication with the first heat exchanger. The first turbine is coupled in flow communication with the first heat exchanger and configured to expand the lean carbon dioxide effluent stream. The carbon dioxide capture system further includes a carbon dioxide membrane unit coupled in flow communication with the first compressor. The carbon dioxide membrane unit is configured to separate the exhaust stream into the lean carbon dioxide effluent stream and a rich carbon dioxide effluent stream. The carbon dioxide membrane unit is further configured to channel the lean carbon dioxide effluent stream to the first heat exchanger.

In a method for liquefying a gas rich in carbon dioxide, the gas is compressed to a first pressure greater than its critical pressure in a compressor to form a compressed gas, the compressed gas is cooled through heat exchange with a refrigerant to a variable temperature to form a cooled compressed gas with a density between 370 and 900 kg/m.sup.3, the cooled compressed gas is cooled at supercritical pressure in a first heat exchanger to a temperature below the critical temperature, the gas cooled below the critical temperature is expanded to a second pressure between 45 and 60 bara to form a diphasic fluid which is separated in a phase separator to form a liquid and a gas, and a liquid portion originating from the phase separator provides cold to the first heat exchanger.

A method for producing power and argon is provided by providing a residual gas stream, purifying the residual gas stream in a front-end purification unit to remove carbon dioxide, thereby forming a purified residual gas stream, and introducing the purified residual gas stream to a cold box, wherein the purified residual gas stream is cooled and expanded within the cold box to produce power and then fed to a distillation column system for separation therein, thereby forming an argon-enriched stream and optionally a nitrogen-enriched stream and/or an oxygen-enriched stream, wherein the residual gas stream is sourced from a retentate stream of a cold membrane having oxygen, nitrogen, carbon dioxide, and argon.

A system for storing or producing electricity, which allows stabilization of a power network under conditions of excess availability of electricity or lack thereof and for producing liquefied natural gas is provided.