A batch process for producing a purified, pressurized liquid carbon dioxide stream, includes withdrawing a liquid carbon dioxide stream (A) from a liquid carbon dioxide supply (10); introducing the liquid carbon dioxide stream (A) into a distillation column (B) having packing (C) therein, and stripping volatile impurities from the liquid carbon dioxide stream with the packing; vaporizing the liquid carbon dioxide stream (A) in a sump (D) of the distillation column (B) for providing a carbon dioxide vapor; withdrawing from a vaporized portion (F) of carbon dioxide vapor in the sump (D) a first vapor stream (G) vented from the distillation column (B); withdrawing from the vaporized portion (F) of the carbon dioxide vapor in the sump (D) a second vapor portion (H) vented from the sump into a conduit (I); and introducing the second vapor portion (H) in the conduit (I) into a carbon dioxide vapor feed stream.

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.

Impurities that are less volatile than carbon dioxide, e.g. hydrogen sulfide, are removed from crude carbon dioxide by processes involving distillation of said crude carbon dioxide in a distillation column system operating at super-atmospheric pressure(s) to produce carbon dioxide-enriched overhead vapor and bottoms liquid enriched with said impurities. Where such processes involve a single heat pump cycle, significant savings in power consumption are realized when the distillation column system is re-boiled by at least partially vaporizing liquid in or taken from an intermediate location in the column system.

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.

In this patent we disclose, for the first time, detailed methods of our newly invented state-of-the-art cryogenic technology for the cost effective energy efficient capture of each known component of entire emissions (nearly 100%) such as carbon dioxide (CO.sub.2), sulfur oxides (SO.sub.x), nitrogen oxides (NO.sub.x), carbon monoxide(CO), any other acid vapor, mercury, steam and unreacted nitrogen from industrial plants (coal and natural gas fired power plants, cement plants etc.), in a liquefied or frozen/solidified form, such that each of the components is captured separately and is industrially useful. This new technology includes a novel NH.sub.3 power plant to generate auxiliary electrical power from the heat energy of the flue gas to further improve the energy efficiency and cost effectiveness of the capture processes. It is the most cost effective of all existing emission capture technologies. It does not require use of any chemicals/reagents/external cryogens, unlike the current technologies. It uses only a fixed amount of water needed for the cooling process which can be used repeatedly. We present detailed methods of operations, together with scientific and economic analysis of the energy needed and cost involved for the said capture in two specific examples, and advantages of the new technology over the existing ones.

In a purification method, a carbon dioxide-rich gas is cooled in a first brazed aluminum plate-fin heat exchanger, the cooled gas or at least one fluid derived from the cooled gas is sent to a purification step comprising a distillation step, the purification step produces a carbon dioxide-rich liquid which is cooled, then expanded, then sent to a second heat exchanger where it is heated by means of a fluid of the method, the exchanger carrying out an indirect heat exchange only between the carbon dioxide-rich liquid and the fluid of the method, the carbon dioxide-rich liquid at least partially vaporizes in the second exchanger and the vaporized gas formed heats up again in the first exchanger to form a carbon dioxide-rich gas.

The power required to recover C.sub.3+ hydrocarbons from crude carbon dioxide comprising C.sub.1+ hydrocarbons and hydrogen sulfide may be reduced by distilling the crude carbon dioxide to produce carbon dioxide-enriched overhead vapor and C.sub.3+ hydrocarbon-enriched bottoms liquid such that the hydrogen sulfide is rejected with the overhead vapor. Power consumption reductions may be achieved by incorporating a heat pump cycle using carbon dioxide vapor as working fluid to provide at least a part of the refrigeration duty and using a side reboiler to reduce the bottom reboiler duty. Where the bottoms liquid is further processed to produce lighter and heavier hydrocarbon fractions, the process enables optimization of upgrading crude oil on the basis of API gravity, Reid Vapor pressure and/or viscosity.

In a process for separating at least one heavy impurity such as hydrogen sulfide from crude carbon dioxide comprising significant quantities of at least one light impurity such as non-condensable gases, involving at least one heat pump cycle using carbon dioxide-containing fluid from the process as the working fluid, the light impurity is removed from the crude carbon dioxide and carbon dioxide is subsequently recovered from the removed light impurity, thereby improving overall carbon dioxide recovery and efficiency in terms of energy consumption.

A carbon dioxide-rich mixture is cooled in a first brazed aluminum plate-fin heat exchanger, at least one fluid derived from the cooled mixture is sent to a purification step having a distillation step and/or at least two successive partial condensation steps, the purification step produces a carbon dioxide-depleted gas which heats up again in the first exchanger, the purification step produces a carbon-dioxide rich liquid which is expanded, then sent to a second heat exchanger where it is heated by means of a fluid of the method, the exchanger carrying out an indirect heat exchange only between the carbon dioxide-rich liquid and the fluid of the method, the carbon dioxide-rich liquid at least partially vaporizes in the second exchanger and the vaporized gas formed heats up again in the first exchanger to form a carbon dioxide-rich gas which can be the end product of the method.