TW201314153A - Heat integration for cryogenic CO2 separation - Google Patents

Abstract

The present invention relates to a flue gas treatment system for removing CO2 from a flue gas stream wherein the system comprises a flue gas compressor, at least one flue gas adsorption drier, a refrigeration system and a stripper column allowing distillation. Also a method for condensation of carbon dioxide (CO2) in a flue gas stream comprising a step of separation by distillation of the condensed CO2 is provided by the invention.

Description

Thermal integration for cryogenic separation of carbon dioxide

The present invention relates to a method and system for separating CO ₂ from a flue gas stream by chilling a CO ₂ -rich flue gas stream to condense the CO ₂ present therein.

When a fuel such as coal, oil, peat, waste, or the like is burned in a combustion apparatus (for example, a power generation facility), a hot process gas is generated, which particularly contains (more than other components) carbon dioxide CO ₂ . As environmental requirements have increased, various processes for self-contained gas removal of carbon dioxide have been developed.

CO ₂ capture typically involves cooling or compressing and cooling the flue gas to condense CO _{2 in} liquid or solid form and separate it from non-condensable flue gas components (eg, N ₂ and O ₂ ). It is often necessary to purge the carbon dioxide-rich flue gas before capturing CO ₂ . Gas cleaning operations can typically involve the removal of dust, sulfur compounds, metals, nitrogen oxides, and the like.

The flue gas can be cooled to its condensation temperature by various means, such as using a suitable external refrigerant. A CO ₂ capture system using an external refrigerant can be expensive in terms of both investment cost and operating cost. According to an alternative embodiment, the refrigeration system is generally used automatic, where the CO-rich _flue gas is compressed, cooled and expanded to condense CO _2.

In such systems, the use of liquid CO ₂ product was used as a cooling medium of the CO-rich flue gas of _2. Since the synchronization between the heat sealing temperature and the manner of condensing systems, and a plurality of such evaporation exchange medium, typically brazed aluminum heat exchangers for CO ₂ condensation. In addition to being more expensive, aluminum is also prone to fouling due to many trace components (such as mercury and particulate matter) contained in flue gases from fossil fuel combustion. Thus, automatic refrigeration systems generally require a lot of work to remove harmful ingredients step of condensing the flue ₂ upstream of the CO gas, for example, require the particulate filter, and the mercury adsorber SO _X / NO _X scrubber. Accordingly, there is a need for systems and methods in which the apparatus can be used in a method of removing carbon dioxide.

It is an object of the present invention to provide a system and method for removing carbon dioxide from a flue gas stream, such as that produced in a boiler that burns fuel in the presence of an oxygen-containing gas, such systems and methods alleviating at least one of the above problems.

According to various aspects set forth herein, the flue gas is removed from the flue gas treating system and method allows for the use of CO ₂ in a simple and stable design and material cost of the heat exchanger efficiently separated CO _2.

According to the aspect set forth herein, a refrigeration system for condensing carbon dioxide (CO ₂ ) in a flue gas stream is provided, the system comprising a flue gas compressor, at least one flue gas adsorption dryer, a refrigeration system, For condensing carbon dioxide (CO ₂ ) in a flue gas stream, the system includes a refrigerant circuit including a refrigerant, the refrigerant circuit including: a multi-stage refrigerant compressor, a refrigerant condenser, and a refrigerant quenching a flue gas chiller, at least one condenser, and a stripper that allows distillation; wherein the flue gas chiller is disposed between the flue gas compressor and the flue gas adsorption dryer, and the flue gas is adsorbed and dried The at least one condenser and the at least one condenser are arranged in series upstream of the stripper.

According to some embodiments, the flue gas treatment system further includes another condenser, wherein the first condenser is disposed in series upstream of the second condenser.

By arranging two or more condensers in series with a gas/liquid separator interposed therebetween, the efficiency of energy consumption can be optimized because cooling can be performed step by step rather than in only one step.

According to an embodiment, the flue gas treatment system further includes a heat exchanger configured to cool at least a portion of the condensing refrigerant using the CO ₂ depleted flue gas from the second CO ₂ condenser.

According to some embodiments, the flue gas treatment system further includes a first heat exchanger configured to cool at least a portion of the condensing refrigerant using the CO ₂ depleted flue gas from the stripper, the second heat exchange And configured to reheat the CO ₂ depleted flue gas from the first refrigerant chiller using the warm flue gas from the flue gas compressor, the first flue gas expander configuration from the first heat exchanger so that the CO ₂ depleted flue gas of compressed expanded reheated, the third heat exchanger, which is configured by using the flue gas from the expander of the CO ₂ depleted flue of The gas further cools the condensing refrigerant from the first refrigerant chiller, and the fourth heat exchanger is configured to reheat the second heat exchanger using the warm flue gas from the flue gas compressor a CO ₂ depleted flue gas, a second flue gas expander configured to expand the reheated compressed flue gas from the second heat exchanger for CO ₂ depletion, and optionally, a fifth heat An exchanger configured to reheat the CO ₂ depleted flue gas from the third exchanger.

According to some embodiments, the flue gas treatment system further includes a first heat exchanger configured to cool at least a portion of the condensing refrigerant using the CO ₂ depleted flue gas from the stripper, the second heat exchange And configured to reheat the CO ₂ depleted flue gas from the first heat exchanger using a warm flue gas from a flue gas compressor, the first flue gas expander configured from the second heat exchanger so that the CO ₂ depleted flue gas of compressed expanded reheated, the third heat exchanger, which is configured by using the flue gas from the expander of the CO ₂ depleted flue gas is further Cooling the condensing refrigerant from the first heat exchanger, a second flue gas expander configured to expand the CO ₂ depleted reheated compressed flue gas from the second heat exchanger, and fourth A heat exchanger configured to reheat the CO ₂ depleted flue gas from the third exchanger.

According to some embodiments, the flue gas treatment system further comprises a selective catalytic reduction (SCR) unit for removing nitrogen oxides (NOx) from the flue gas stream and referring to CO ₂ depletion The general flow direction of the flue gas stream is disposed downstream of the flue gas adsorption dryer.

According to the aspect set forth herein, a method of condensing carbon dioxide (CO ₂ ) in a flue gas stream using an external refrigerant is provided, the method comprising a) compressing and at least partially condensing an external refrigerant to obtain a condensation external a refrigerant, b) condensing CO ₂ in the flue gas stream by at least partially vaporizing the condensed external refrigerant obtained in step a) to condense the flue gas stream, c) condensing by distillation from the flue gas stream CO _{2 is} used for the separation, and d) the condensed external refrigerant used for the refrigeration of step b) is quenched using the condensed CO ₂ separated in step c).

According to some methods, the external refrigerant is propane or propylene.

According to some methods, the external refrigerant is ammonia.

The above and other features are exemplified by the following figures and detailed description. Other objects and features of the present invention will become apparent from the description.

Unless otherwise specified, the pressures herein are expressed in units of bar and indicate absolute pressure.

The term "indirect" or "indirectly" as used herein in connection with heat exchange between two fluids (eg, heating, cooling, or quenching) means that the heat exchange occurs without mixing the two fluids together. The indirect heat exchange can be performed, for example, in an indirect contact heat exchanger wherein the fluid flow remains in a separated state and the heat is continuously transferred via the impermeable partition wall.

Various aspects of the refrigeration system or flue gas treatment system disclosed herein can be implemented, for example, in a combustion facility, such as a boiler system that burns fossils. Application of such systems and methods is not limited, it is generally used for all gas stream with increased _{concentration} of CO (e.g. the CO ₂ concentration greater than 50%) of.

Typically, the flue gas exiting the fossil-containing oxygen-containing boiler system contains 50-80% by volume of carbon dioxide. The remainder of the "carbon dioxide-rich flue gas" is about 15-40% by volume of water vapor (H ₂ O), 2-7 vol% of oxygen (O ₂ ) (this is because oxygen is usually preferred in boilers). There is an excess) and a total of about 0-10% by volume of other gases (mainly containing nitrogen (N ₂ ) and argon (Ar), because it is difficult to completely avoid leakage of some air).

In the oxygen-generating boiler system of the combustion of fossil carbon dioxide rich flue gas may typically comprise form (e.g.) in the form of contaminants: dust particles, HCl hydrochloric acid, nitrogen oxide NO _X, SO _X sulfur oxides and heavy metals ( Contains mercury Hg).

By means of flue gas and the compressed refrigerant is condensed by the separation achieved in Example ₂ herein, the CO embodiment set forth. 1 illustrates a schematic view illustrating a flue gas stream for condensation of carbon dioxide (CO ₂₎ of the CO ₂ separation systems. The CO ₂ separation system of Figure 1 can be implemented in any of the fossil-containing oxygen-containing boiler systems. The CO ₂ separation system 10 includes a flue gas conduit 55 that is adapted to be used to flue the flue via one or more flue gas treatment units (eg, a dust removal device, a sulfur dioxide removal system, and a flue gas condenser) as appropriate. Gas is transferred from the boiler to the stack.

The CO ₂ separation system 10 may optionally include at least one compressor 44 having at least one and typically two to ten compression stages for compressing the carbon dioxide rich flue gas. The flue gas compressor is adapted to compress the flue gas to a gaseous CO ₂ conversion to a decrease in the temperature of the flue gas in at least one of the CO ₂ condensers 70 (eg, in the two CO ₂ condensers 64, 70) The pressure in liquid form. The carbon dioxide-rich flue gas is typically compressed to a pressure of about 20 bar or higher (e.g., about 33 bar) in a multi-stage compressor. Each compression stage can be configured as a separate unit. According to an alternative, several compression stages can be operated by a common drive shaft. Compressor 44 may also include an intermediate cooling unit (not shown) downstream of one or more compression stages. The intermediate cooling unit can be further configured to collect and dispose of any liquid condensate formed during the compression and/or cooling of the carbon dioxide rich flue gas.

The CO ₂ separation system 10 includes a refrigeration system 50 having a refrigeration circuit 51 containing a refrigerant in the form of a liquid and/or vapor. Many different refrigerants can be used to supply the cooling and condensing load on the refrigeration system ₂ of the desired condensed CO. Examples of the refrigerant which can be used include propane (R290) and propylene (R1270) and a mixture thereof. Another option is ammonia. Other refrigerants having desired thermodynamic and chemical properties may also be used as needed.

The refrigeration circuit 51 includes a multi-stage refrigerant compressor 52 configured to compress the refrigerant to a predetermined pressure. The multi-stage compressor 52 can, for example, have three or more compression stages, each of which is configured to compress the refrigerant to a certain pressure value. The multi-stage compressor 52 can provide intermediate cooling between two or more compression stages.

Compressing the cold gaseous refrigerant from the low pressure in the multistage compressor 52 to a pressure P0 (eg, between about 8 and 25 bar (end-of-coolant and condensing medium temperature)) and directing to the refrigerant In the condenser 53. The high pressure refrigerant is then substantially condensed in a condenser condenser 53 which can be cooled by water, forced air or the like.

The condensing refrigerant is distributed to the flue gas chiller 60, the first CO ₂ condenser 64, and the second CO ₂ condenser 70, wherein the condensing refrigerant is used to quench the flue gas containing CO ₂ .

The flue gas chiller 60 includes a metering device (e.g., an expansion valve (not shown)) for reducing the pressure and causing evaporation of the condensing refrigerant. The flue gas chiller further includes a heat exchanger wherein the refrigerant is expanded to a pressure P1 (e.g., about 5 bar) and the flue gas stream is indirectly quenched to a temperature in the range of about 10-20 °C using a boiling refrigerant. The water precipitated from the flue gas during quenching in the flue gas chiller is separated from the flue gas stream and removed via line 61. Then from the cooler flue shortness of the water vapor depleted flue gas quenching optionally transmitting to the condenser 64 via the first CO ₂ capture adsorption drier (not shown).

First CO ₂ capture condenser 64 comprises a metering device (e.g., an expansion valve (not shown)) for reducing the pressure of the refrigerant is condensed and evaporated and the initiator. The first CO ₂ condenser 64 further includes a heat exchanger in which the liquefied refrigerant is expanded to a pressure P2 (<P1, for example, about 2.7 bar), and the flue gas stream is indirectly quenched to about -20 ° C using a boiling refrigerant. The temperature is such that at least a portion of the CO ₂ from the flue gas condenses. The first CO ₂ condenser 64 further includes a first gas/liquid separator 65. The gas/liquid separator 65 separates the condensed CO _{2 in} a liquid form from the residual flue gas (exhaust gas) which is partially consumed by CO ₂ . The liquefied CO ₂ exits the gas/liquid separator 65 via line 66 and is pumped into the CO ₂ product drum by the CO ₂ product pump 67. Exhaust gas exits gas/liquid separator 65 via line 68.

Via line 68 is partially depleted exhaust gas CO ₂ in the CO ₂ transmitting to the second condenser 70. The second CO ₂ condenser 70 comprises a metering device (e.g., an expansion valve (not shown)) for reducing the pressure of the refrigerant is condensed and evaporated and the initiator. The second CO ₂ condenser 70 further includes a heat exchanger in which the liquefied refrigerant is expanded to a pressure P3 (<P2, such as atmospheric pressure (about 1 bar)), and the flue gas stream is indirectly quenched to about using a boiling refrigerant. A temperature of -42 ° C to condense at least a portion of the CO ₂ from the flue gas. The cooling temperature is limited by the minimum temperature of the refrigerant. For propylene or propane, this temperature limit is about -45 ° C at ambient pressure.

CO ₂ from the second section of the condenser 70 to condense the flue gas stream to transmit to the stripping column 71 for purification of liquid by distillation. The stream is fed at the top of the stripper and the liquid portion is used as the desired reflux. Therefore, the stripper does not require any overhead condensing system for generating reflux. Therefore, the overall investment cost of the system is minimized. The liquefied CO ₂ flows down the stripper and is in full contact with the upward flowing gas. This contact extracts (stripping) trace impurities of liquid CO ₂ and thereby increases the concentration of CO ₂ . Purified CO ₂ exits stripper 71 via line 72 to stripping reboiler 84. In the reboiler, a portion of the CO ₂ vaporizes to produce the gas stream required by the stripper. Heat is provided by a portion of the supercooled refrigerant.

The remaining liquid can be withdrawn from the reboiler from the stripper tank or (as shown) and subsequently pumped by CO ₂ pump 86 via another heat exchanger 85 into the CO ₂ product drum, where the refrigerant is Cool to about 1-5 ° C, such as 3-4 ° C. In the drum, the pressure of the CO ₂ product is raised by the CO ₂ product pump 88 to the value required for further processing.

The refrigeration system 50 further includes a refrigerant chiller 80. The refrigerant chiller 80 via configured to include a liquid CO ₂ by indirect contact with the cold purified from the quench stripper 71 to the refrigerant of the heat exchanger. The temperature of the condensed CO ₂ from the first and second CO ₂ condensers 64, 70 can generally be about -20 ° C and -42 ° C, respectively. In the refrigerant chiller 80, the temperature of the refrigerant can be reduced from about 15-30 ° C to about 1 ° C.

The temperature of the condensed CO ₂ from the first and second CO ₂ condensers 64, 70 can generally be about -20 ° C and -42 ° C, respectively. In the refrigerant chiller 80, the temperature of the refrigerant can be reduced from about 15-30 ° C to about 1 ° C.

The evaporative refrigerant from the flue gas quencher 60, the first CO ₂ condenser 64, and the second CO ₂ condenser 70 is returned to the multistage compressor 52 for recompression and used to further cool the flue after condensation airflow. The evaporative refrigerant from the flue gas chiller 60 at a pressure P1 (e.g., about 5 bar) is transferred to a first compression stage 52' of the multi-stage compressor 52 adapted to receive a refrigerant having a pressure P1. The evaporating refrigerant from the first CO ₂ condenser 64 at a pressure of P2 (e.g., about 2.7 bar) is transferred to the multi-stage compressor 52 via the refrigerant compressor suction drum 56 as appropriate to receive pressure. The second compression stage 52" of the refrigerant of P2. The evaporation from the second CO ₂ condenser 70 is P3 (for example, about 1 bar) by the refrigerant compressor suction drum 57 as the case may be. The agent is transferred to a third compression stage 52"" of the multi-stage compressor 52 adapted to receive a refrigerant having a pressure of P3. The evaporated refrigerant stream is then recompressed to a pressure P0 and reused in a refrigeration circuit. .

Chiller refrigerant pressure of the liquid CO ₂ 80 CO ₂ product was collected in the product drum 87 and then by CO ₂ product pressurization pump 88 is adapted to transport or further processing of the can from the. If the pressure is increased to this value in a single step in the CO ₂ product pump 67 or 73, the pump will introduce excess heat into the CO ₂ product stream and thereby reduce the usefulness in the refrigerant chiller and/or Or the load of the quenching refrigerant in the auxiliary refrigerant chiller.

Figure 2 is a schematic illustration of the implementation of a CO ₂ separation system integrated into a flue gas treatment system for the removal of CO ₂ from a flue gas stream (e.g., a flue gas stream generated in a boiler combustion fuel in the presence of an oxygen containing gas) example.

The CO ₂ separation system 110 includes at least one compressor 144 having at least one and typically two to ten compression stages for compressing the carbon dioxide rich flue gas. Flue gas compressor 144 is adapted to the flue gas is compressed to a gaseous CO ₂ conversion to liquid form in the temperature of the flue gas in a CO ₂ has been reduced in the pressure in the condenser 164, 170. The carbon dioxide-rich flue gas is typically compressed to a pressure of about 20 bar or higher (e.g., about 33 bar) in a multi-stage compressor. Each compression stage can be configured as a separate unit. According to an alternative, several compression stages can be operated by a common drive shaft. Compressor 144 may also include an intermediate cooling unit (not shown) downstream of one or more compression stages. The intermediate cooling unit can be further configured to collect and dispose of any liquid condensate formed during the compression and/or cooling of the carbon dioxide rich flue gas.

Residual water can cause ice to form in the heat exchanger of the CO ₂ condenser, ultimately causing problems of reduced cooling capacity and clogging of the heat exchanger. By providing CO ₂ adsorption drier in the upstream of the condenser, such problems can be avoided or at least reduced to a minimum. Accordingly, the CO ₂ separation system 110 can further include an adsorption dryer 162 that is adapted to remove at least a portion of the remaining water vapor in the CO ₂ rich flue gas stream. The adsorption dryer 162 is provided with a filler including a water vapor adsorbent, which is also referred to as a desiccant and has an affinity for water vapor. The desiccant can be, for example, silicone, calcium sulfate, calcium chloride, smectite clay, molecular sieves or another material known to be useful as a desiccant. Thus, as the carbon dioxide-rich compressed and quenched flue gas passes through the packing, at least a portion of the contents of the gas vapor will adsorb to the desiccant of the packing. Since the water vapor of the flue gas can block the heat exchanger of the CO ₂ condenser, the water dew point of the flue gas is reduced to about -60 ° C in the adsorption dryer. The dryer material can be preferably selected such that it can withstand the acid that is ultimately formed. This eliminates the need for such additional steps of SO _X and NO _X removal of the original compound can jeopardize the integrity of the sorbent.

The adsorption dryer 162 can be provided with a regeneration and heating system for the water vapor adsorption capacity of the interstitial regenerative adsorption dryer. Supply conduit 190 is configured for supplying regeneration gas to the system. The regeneration gas is preferably an inert gas which does not react with the filler of the adsorption dryer. Examples of suitable gases include nitrogen or another inert gas that preferably contains a low amount of mercury and water vapor. Preferably, an exhaust gas which generally includes nitrogen as a main component and is separated from carbon dioxide in the CO ₂ separation system 110 is used as the regeneration gas. The regeneration system includes a heater 191 adapted to heat the regeneration gas. A heating circuit is connected to the heater for circulating a heating medium (eg, steam) in the heater. To regenerate the packing material of the adsorption dryer 162, the heater typically heats the regeneration gas to a temperature of about 120-300 °C. The heated regeneration gas is supplied to the adsorption dryer 162 from the regeneration and heating system during the regeneration sequence. The regeneration gas heats the filler material and desorbs the water vapor.

According to an embodiment, the system can be provided with two parallel adsorption dryers, wherein one of the parallel adsorption dryers is in an operational state and the other parallel adsorption dryer is regenerated. According to another embodiment, the carbon dioxide-rich flue gas can be vented to the atmosphere during regeneration of the sorbent dryer packing.

Referring to Figure 2, flue gas CO ₂ separation system 110 comprises a refrigeration system for carbon dioxide in the flue gas stream 150 is condensed. The refrigeration system 150 includes a refrigeration circuit 151 containing a refrigerant in the form of a liquid and/or vapor. Many different refrigerants can be used to supply the cooling and condensing load on the refrigeration system ₂ of the desired condensed CO. Examples of the refrigerant which can be used include propane (R290) and propylene (R1270) and a mixture thereof. Other refrigerants having desired thermodynamic and chemical properties may also be used as needed.

The refrigeration circuit 151 includes a multi-stage refrigerant compressor 152 configured to compress the refrigerant to a predetermined pressure. The multi-stage compressor can, for example, have three or more compression stages, each of which is configured to compress the refrigerant to a certain pressure value. A multi-stage compressor can provide intermediate cooling between two or more compression stages.

Compressing the cold gaseous refrigerant from the low pressure in the multi-stage compressor 152 to a pressure P0 (e.g., between about 8 bar and about 25 bar (end-view refrigerant and condensing medium temperature)) and directing to refrigeration In the condenser 153. The high pressure refrigerant is then substantially condensed in a refrigerant condenser 153 which can be cooled by water, forced air or the like.

The condensing refrigerant is distributed to the flue gas chiller 160, the first CO ₂ condenser 164, and the second CO ₂ condenser 170, wherein the condensing refrigerant is used to quench the CO ₂ containing gas and in the flue gas duct 155 The flue gas that travels in the middle.

The flue gas chiller 160 includes a metering device (e.g., an expansion valve (not shown)) for reducing the pressure and causing evaporation of the condensing refrigerant. The flue gas chiller further includes a heat exchanger wherein the refrigerant is expanded to a pressure P1 (e.g., about 5 bar) and the flue gas stream is indirectly quenched to a temperature in the range of about 6-20 °C using a boiling refrigerant. The water precipitated from the flue gas during quenching in the flue gas chiller is separated from the flue gas stream and removed via line 161. The quenched flue gas from the flue gas chiller that is depleted of water vapor is then transferred to the sorption dryer 162.

The quenched and dried flue gas from the adsorption dryer 162 is transferred to the first CO ₂ condenser 164. First CO ₂ capture condenser comprising a metering device (e.g., an expansion valve (not shown)) for reducing the pressure of the refrigerant is condensed and evaporated and the initiator. The first CO ₂ condenser further includes a heat exchanger in which the liquefied refrigerant is expanded to a pressure P2 (<P1, for example, about 2.7 bar), and the flue gas stream is indirectly quenched to about -20 ° C using a boiling refrigerant. The temperature is such that at least a portion of the CO ₂ from the flue gas condenses. The first CO ₂ condenser 164 further includes a first gas/liquid separator 165. The gas/liquid separator 165 separates the condensed CO _{2 in} a liquid form from the flue gas (exhaust gas) which is partially consumed by the CO ₂ . Liquefied CO ₂ leaves the gas / liquid separator via line 166 165 and 171 transmit to the stripping column.

Part of the CO ₂ depleted exhaust gas is passed via line 168 to the second CO ₂ condenser 170. CO ₂ condenser comprising a second metering device 170 (e.g., an expansion valve (not shown)) for reducing the pressure of the refrigerant is condensed and evaporated and the initiator. The second CO ₂ condenser further includes a heat exchanger wherein the liquefied refrigerant is expanded to a pressure P3 (<P2, such as atmospheric pressure (about 1 bar)), and the flue gas stream is indirectly quenched to about using a boiling refrigerant - A temperature of 42 ° C causes at least a portion of the CO ₂ from the flue gas to condense. The cooling temperature is limited by the minimum temperature of the refrigerant. For propylene or propane, this temperature limit is about -45 ° C at ambient pressure.

Condenser CO ₂ from the second partial condensation of the flue gas stream 170 to stripping column 171 to transmit to the liquid used is purified by distillation. The stream is fed at the top of the stripper and the liquid portion is used as the desired reflux. Therefore, the stripper does not require any overhead condensing system for generating reflux. Therefore, the overall investment cost of the system is minimized. The liquefied CO ₂ flows down the stripper and is in full contact with the upward flowing gas. This contact extracts (stripping) trace impurities of liquid CO ₂ and thereby increases the concentration of CO ₂ . Purified CO ₂ exits stripper 171 via line 172 to stripping reboiler 184. In the reboiler, a portion of the CO ₂ vaporizes to produce the gas stream required by the stripper. Heat is provided by a portion of the supercooled refrigerant. The remaining liquid can be withdrawn from the reboiler from the stripper tank or (as shown) and then pumped by CO ₂ pump 186 via another heat exchanger 185 into the CO ₂ product drum, where the refrigerant is Cool to about 1-5 ° C, such as 3-4 ° C. In the drum, the CO ₂ product by pump 188 so that the pressure of the CO ₂ product was further raised to the desired value of the process.

The refrigeration system 150 further includes a refrigerant chiller 180. Via refrigerant chiller 180 configured to include liquid CO ₂ by indirect contact with the cold purified from stripper 171 to the quenching of the refrigerant heat exchanger.

The temperature of the condensed CO ₂ from the first and second CO ₂ condensers 164, 170 can generally be about -20 ° C and - 42 ° C, respectively. In the refrigerant chiller 180, the temperature of the refrigerant can be reduced from about 15-30 ° C to about 1 ° C.

The refrigeration system 150 further includes a refrigerant chiller 180. The refrigerant chiller 180 configured to include a heat exchanger by indirect contact by liquid CO ₂ was purified from the stripper and the cold refrigerant to quench it.

The temperature of the condensed CO ₂ from the first and second CO ₂ condensers 164, 170 can generally be about -20 ° C and - 42 ° C, respectively. In the refrigerant chiller 180, the temperature of the refrigerant can be reduced from about 15-30 ° C to about 1 ° C.

Separating the quench chiller refrigerant from the refrigerant 180 and distributed to the cold flue shortness of breath 181, 182 via line 160, condenser 164 and the first CO ₂ capture CO ₂ condenser 170 second. Alternatively the distribution of the flue shortness cooler 160, the refrigerant amount of each of the first CO ₂ capture CO ₂ and the second condenser 164 in the condenser 170 to provide a desired heat exchanger in each refrigerant.

May be a liquid refrigerant from chiller 180 of CO ₂ CO ₂ product was collected in the product in the drum 187 and then by CO ₂ product can help pump 188 is pressurized to a pressure value suitable for transmission or further processing it. If the pressure is increased to this value in a single step in the CO ₂ product pump 167 or 173, the pump will introduce excess heat into the CO ₂ product stream and thereby reduce the usefulness in the refrigerant chiller and/or Or the load of the quenching refrigerant in the auxiliary refrigerant chiller.

In Figure 2 the refrigeration system 150 further comprises means for using from the second condenser CO ₂ consumption of the lack of CO ₂ cold flue gas pre-cooling refrigerant is condensed and disposed of at least part of refrigerant from the condenser. The configuration includes a first heat exchanger 192 configured to cool condensation from the refrigerant by indirect contact with the CO ₂ -consuming cold flue gas from the second CO ₂ condenser 170 via line 174. The refrigerant of the device 153. The second heat exchanger 193 is configured to reheat the CO ₂ depleted flue gas from the first heat exchanger 192 using the warm flue gas from the flue gas compressor 144. The flue gas expander 194 is configured to expand the reheated compressed flue gas from the CO ₂ depletion from the second heat exchanger to reduce the temperature of the flue gas. The flue gas from the flue gas expander 194 is transferred to a third heat exchanger 195 where the flue gas from the first heat exchanger is further cooled using the flue gas.

Optionally, the configuration of a flue further comprising a depleted (which was configured using a compressor to warm flue gas from the flue gas 144. reheated CO ₂ from the third heat exchanger 195 of the fourth heat exchanger 196 a second flue gas expander 197 (which is configured to expand the reheat flue gas from the fourth heat exchanger 196 that is depleted of CO ₂ to reduce the temperature of the flue gas) and fifth A heat exchanger 198 (which is configured to reheat the expanded flue gas from the second flue gas expander 197 using the warm flue gas from the flue gas compressor 144). This optional configuration provides for reheating flue gas that may be suitable for use as a regeneration gas for regeneration of the adsorption dryer 162 as described above after additional heating in the regeneration gas heater 191. Reheating the flue gas may be used to transmit the reduction to N ₂ removal from flue gas of the nitrogen oxides SCR unit (optional) by the selective catalytic.

Shortness of breath from the flue so that the intercooler 160, a condenser 164 and a first CO ₂ capture CO ₂ condenser second evaporator 170 of the refrigerant returns to the multistage compressor 152 for recompression and for further cooling the flue gas stream. The evaporative refrigerant from the flue gas chiller 160 at a pressure P1 (e.g., about 5 bar) is transferred to a first compression stage 152' of the multi-stage compressor 152 adapted to receive a refrigerant having a pressure P1. The evaporative refrigerant from the first CO ₂ condenser 164 having a pressure of P2 (e.g., about 2.7 bar) is transferred to the multi-stage compressor 152 via the refrigerant compressor suction drum 156 as appropriate to receive pressure. of P3 (e.g. about 1 bar) P2 of the refrigerant evaporative cooling of the second compression stage 152 "in the. Conditional refrigerant compressor via the suction pressure in the drum 157 from the condenser 170 of the second CO ₂ The agent is transferred to a third compression stage 152"" of the multistage compressor 152 adapted to receive a refrigerant having a pressure of P3. The evaporated refrigerant stream is then recompressed to a pressure P0 and reused in a refrigeration circuit. .

Referring to FIG 3, CO ₂ separation system 210 includes a refrigeration system 250. The refrigeration system 250 includes a refrigeration circuit 251 containing a refrigerant in the form of a liquid and/or vapor. Many different refrigerants can be used to supply the cooling and condensing load on the refrigeration system ₂ of the desired condensed CO. Examples of the refrigerant which can be used include R290 (propane) and R1270 propylene and a mixture thereof. Another option for refrigerants is ammonia. Other refrigerants having desired thermodynamic and chemical properties may also be used as needed.

The refrigeration circuit includes a multi-stage refrigerant compressor 252 configured to compress the refrigerant to a predetermined pressure. The multi-stage compressor can, for example, have three or more compression stages, each of which is configured to compress the refrigerant to a certain pressure value. A multi-stage compressor can provide intermediate cooling between two or more compression stages.

Compressing the cold gaseous refrigerant from the low pressure in the multi-stage compressor 252 to a pressure P0 (e.g., between about 8 bar and about 25 bar (end-of-coolant and condensing medium temperature)) and directing to refrigeration In the condenser 253. The high pressure refrigerant is then substantially condensed in a refrigerant condenser 253 that can be cooled by water, forced air or the like.

The refrigeration circuit 251 includes a liquid splitter that divides the flow of refrigerant from the refrigerant condenser 253 into first and second portions.

Line 254a of the first portion of the condensed refrigerant is directed to the configured by using a portion of the liquid through the separation in the stripping column 271 is condensed refrigerant CO ₂ in the quenching of the quench refrigerant vessel 280. A second portion of the condensing refrigerant is directed to a heat exchanger configuration via line 254b that is configured to cool the condensation using the CO ₂ depleted flue gas from the second CO ₂ condenser 270 The second part of the refrigerant.

The first portion of the condensed refrigerant is transferred from the refrigerant condenser 253 to the refrigerant chiller 280 via line 254a. The refrigerant chiller configured to include a heat exchanger by indirect contact with cold ₂ by condensing the CO 271 from the stripper to quench the refrigerant.

Condenser CO ₂ from the second partial condensation of the flue gas stream 270 to stripping column 271 to transmit to the liquid used is purified by distillation.

The stream is fed at the top of the stripper and the liquid portion is used as the desired reflux. Therefore, the stripper does not require any overhead condensing system for generating reflux. Therefore, the overall investment cost of the system is minimized. The liquefied CO ₂ flows down the stripper and is in full contact with the upward flowing gas. This contact extracts (stripping) trace impurities of liquid CO ₂ and thereby increases the concentration of CO ₂ . Purified CO ₂ exits stripper 271 via line 272 to stripping reboiler 284. In the reboiler, a portion of the CO ₂ vaporizes to produce the gas stream required by the stripper. The heat is supplied by the air flow required to supercool the stripper. Heat is provided by a portion of the supercooled refrigerant.

The remaining liquid can be withdrawn from the reboiler from the stripper tank or (as shown) and subsequently pumped by CO ₂ pump 81 via another heat exchanger 285 into the CO ₂ product drum, where the refrigerant is Cool to about 1-5 ° C, such as 3-4 ° C. In the drum, the CO ₂ product by pump 288 so that the pressure of the CO ₂ product was further raised to the desired value of the process.

The refrigeration system 250 further includes a refrigerant chiller 280. Via refrigerant chiller 280 configured to include liquid CO ₂ by indirect contact with the cold purified from the quench stripper 71 to the refrigerant of the heat exchanger.

The temperature of the condensed CO ₂ from the first and second CO ₂ condensers 264, 270 can generally be about -20 ° C and -42 ° C, respectively. In the refrigerant chiller 280, the temperature of the refrigerant can be reduced from about 15-30 ° C to about 1 ° C.

Alternatively the distribution of the flue shortness cooler 260, the refrigerant amount of each of first CO ₂ capture CO ₂ and the second condenser 264 in the condenser 270 in the desired order to provide a heat exchanger in each refrigerant.

The flue gas chiller 260 includes a metering device (e.g., an expansion valve (not shown)) for reducing the pressure and causing evaporation of the condensing refrigerant. The flue gas chiller further includes a heat exchanger wherein the refrigerant is expanded to a pressure P1 (e.g., about 5 bar) and the flue gas stream is indirectly quenched to a temperature in the range of about 6-20 °C using a boiling refrigerant. The water precipitated from the flue gas during quenching in the flue gas chiller is separated from the flue gas stream and removed via line 261. Shortness of breath from the flue then quench cooler of the water vapor depleted flue gas 262 optionally transmitting to the condenser 264 via the first CO ₂ capture adsorption drier.

First CO ₂ capture condenser comprising a metering device (e.g., an expansion valve (not shown)) for reducing the pressure of the refrigerant is condensed and evaporated and the initiator. The first CO ₂ condenser further includes a heat exchanger in which the liquefied refrigerant is expanded to a pressure P2 (<P1, for example, about 2.7 bar), and the flue gas stream is indirectly quenched to about -20 ° C using a boiling refrigerant. The temperature is such that at least a portion of the CO ₂ from the flue gas condenses. The first CO ₂ condenser 264 further includes a first gas/liquid separator 265. The gas/liquid separator 265 separates the condensed CO ₂ in liquid form from the residual flue gas (exhaust gas) which is partially consumed by CO ₂ . The liquefied CO ₂ exits the first gas/liquid separator 265 via line 266 and is pressurized by the CO ₂ product pump 267 to prevent evaporation of the CO ₂ product when used to cool the refrigerant in the cryogen chiller 280. The pressure (for example, about 60 bar). Exhaust gas exits gas/liquid separator 265 via line 268.

Via line 268 is partially depleted of CO ₂ gas is discharged to the second transmitting CO ₂ condenser 270. Second metering means comprises a condenser CO ₂ (e.g., an expansion valve (not shown)) for reducing the pressure of the refrigerant is condensed and evaporated and the initiator. The second CO ₂ condenser further includes a heat exchanger wherein the liquefied refrigerant is expanded to a pressure P3 (<P2, such as atmospheric pressure (about 1 bar)), and the flue gas stream is indirectly quenched to about using a boiling refrigerant - A temperature of 42 ° C causes at least a portion of the CO ₂ from the flue gas to condense. The cooling temperature is limited by the minimum temperature of the refrigerant. For propylene or propane, this temperature limit is about -45 ° C at ambient pressure. The second CO ₂ condenser further includes a gas/liquid separator 271. The gas/liquid separator 271 separates the condensed CO _{2 in} a liquid form from the residual flue gas (exhaust gas) which is partially consumed by CO ₂ .

Condenser CO ₂ from the second partial condensation of the flue gas stream 270 to stripping column 271 to transmit to the liquid used is purified by distillation. The stream is fed at the top of the stripper and the liquid portion is used as the desired reflux. Therefore, the stripper does not require any overhead condensing system for generating reflux. Therefore, the overall investment cost of the system is minimized. The liquefied CO ₂ flows down the stripper and is in full contact with the upward flowing gas. This contact extracts (stripping) trace impurities of liquid CO ₂ and thereby increases the concentration of CO ₂ . Purified CO ₂ exits stripper 271 via line 272 to stripping reboiler 284. In the reboiler, a portion of the CO ₂ vaporizes to produce the gas stream required by the stripper. Heat is provided by a portion of the supercooled refrigerant.

The remaining liquid can be withdrawn from the reboiler from the stripper tank or (as shown) and then pumped via CO ₂ pump 286 to the CO ₂ product drum via another heat exchanger where the refrigerant is cooled To about 1-5 ° C, such as 3-4 ° C. In the drum, the CO ₂ product by pump 288 so that the pressure of the CO ₂ product was further raised to the desired value of the process.

When the pump 273 in a single step to increase the pressure to this value in a CO ₂ product, excessive heat pump will help the liquid CO ₂ product stream is introduced and thereby the refrigerant can be used to reduce the quench-induced quench 280 The load of the refrigerant.

A second portion of the condensing refrigerant is directed to a heat exchanger configuration via line 254b that is configured to cool the condensation using the CO ₂ depleted flue gas from the second CO ₂ condenser 270 The second part of the refrigerant. The heat exchanger configuration includes two heat exchangers 292a, 292b arranged in parallel. The second portion of the condensing refrigerant from the refrigerant condenser is split into two substreams, each substream being directed toward one of the two heat exchangers via lines 254b1 and 254b2, respectively. Configured to use the heat exchanger 292a through the sub-air cooling of the condensed refrigerant from the condenser 270 of the second CO ₂ CO ₂ depleted stream of flue 254b1. The heat exchanger 293 is configured to reheat the CO ₂ depleted flue gas from the heat exchanger 292a using the warm flue gas from the flue gas compressor 244. Flue gas through the expander 294 configured from the heat exchanger 293 so that the CO ₂ depleted flue gas of compressed expanded reheated. The heat exchanger 292b configured by using the CO from the flue gas to the expander 294 of ₂ depleted flue gas cooling the refrigerant condensed substream of the stream 254b2. The first and second cooling substreams from heat exchangers 292a, 292b are combined and passed via line 295 to line 283 where they are combined with refrigerant from auxiliary refrigerant chiller 286.

Optionally, the configuration further includes a heat exchanger 296 configured to reheat the spent CO ₂ gas from the heat exchanger 292b using the warm flue gas from the flue gas compressor 244, Two flue gas expanders 297 (which are configured to expand the reheat flue gas from the heat exchanger 296 that is depleted of CO ₂ to reduce the temperature of the flue gas) and the heat exchanger 298 The state reheats the expanded flue gas from the second flue gas expander 297 using the warm flue gas from the flue gas compressor 244. This optional configuration provides a reheating flue gas suitable for use as a regeneration gas for regeneration of the adsorption dryer 262 as described above after additional heating in the regeneration gas heater 291.

Optionally, reheating the flue gas may be used to transmit the reduction to N ₂ removal from flue gas of the nitrogen oxides SCR unit (optional) by the selective catalytic.

Shortness of breath from the flue so that the intercooler 260, a condenser 264 and a first CO ₂ capture CO ₂ condenser second evaporator 270 of the refrigerant returns to the multistage compressor 252 for recompression and for further cooling the flue gas stream. The evaporative refrigerant from the flue gas chiller 260 at a pressure P1 (e.g., about 5 bar) is transferred to a first compression stage 252' of the multistage compressor 252 adapted to receive a refrigerant having a pressure P1. The evaporating refrigerant from the second CO ₂ condenser 264 at a pressure of P2 (e.g., about 2.7 bar) is transferred to the multi-stage compressor 252 via the refrigerant compressor suction drum 256 as appropriate to receive pressure. The second compression stage 252" of the refrigerant of P2. The evaporation from the second CO ₂ condenser 270 is P3 (for example, about 1 bar) by the refrigerant compressor suction drum 257 as the case may be. The agent is transferred to a third compression stage 252"" of the multi-stage compressor 252 adapted to receive a refrigerant of pressure P3. The vaporized refrigerant stream is then recompressed in a multi-stage compressor 252 to a pressure P0 and Reuse in the refrigeration circuit.

Advantages of the above embodiments include: - lower energy consumption compared to conventional cryogenic CO ₂ separation systems; - permitting the use of simple, stable heat exchanger designs and materials that are stable to fouling and corrosion; - no need for process Flue gas polishing equipment for reasons; - allows for simpler equipment design; - allows for more conventional and simple equipment and allows the use of carbon steel downstream of the dryer; - allows CO to be transported via a pump rather than a more costly compression ₂ ; - A simpler process solution, which does not have an overhead system, such as an overhead steam condenser, a reflux drum and a return pump.

Although the present invention has been described with reference to a number of preferred embodiments, those skilled in the art should understand that various changes can be made to the embodiments and equivalents can be substituted for the elements thereof without departing from the invention. The scope of the invention. In addition, many modifications may be made to the teachings of the present invention without departing from the scope of the invention. Therefore, the present invention is not intended to be limited to the specific embodiments disclosed as the preferred embodiment of the invention, but is intended to be In addition, the use of the terms first, second, etc. does not denote any order or importance, and the terms first, second, etc. are used to distinguish one element from another.

10‧‧‧CO ₂ separation system

44‧‧‧Compressor

50‧‧‧ Refrigeration system

51‧‧‧ refrigeration circuit

52‧‧‧Multi-stage refrigerant compressor

52'‧‧‧First compression stage

52"‧‧‧second compression stage

52'''‧‧‧ Third compression stage

53‧‧‧Refrigerant condenser

55‧‧‧ Flue gas duct

56‧‧‧Refrigerant compressor suction drum

57‧‧‧Refrigerant compressor suction drum

60‧‧‧ Flue gas cooler

64‧‧‧First CO ₂ condenser

65‧‧‧First gas/liquid separator

66‧‧‧ pipeline

68‧‧‧ pipeline

70‧‧‧Second CO ₂ condenser

71‧‧‧Stripper

80‧‧‧refrigerator chiller

84‧‧‧ Stripping reboiler

85‧‧‧ heat exchanger

86‧‧‧CO ₂ pump

87‧‧‧CO ₂ product drum

88‧‧‧CO ₂ product pump

110‧‧‧CO ₂ separation system

144‧‧‧ Flue gas compressor

150‧‧‧ Refrigeration system

151‧‧‧ refrigeration circuit

152‧‧‧Multi-stage refrigerant compressor

152'‧‧‧First compression stage

152"‧‧‧second compression stage

152'''‧‧‧ Third compression stage

153‧‧‧Refrigerant condenser

155‧‧‧ flue gas duct

156‧‧‧Refrigerant compressor suction drum

157‧‧‧Refrigerant compressor suction drum

160‧‧‧ Flue gas cooler

161‧‧‧ pipeline

162‧‧‧Adsorption dryer

164‧‧‧First CO ₂ condenser

165‧‧‧First gas/liquid separator

166‧‧‧ pipeline

168‧‧‧ pipeline

170‧‧‧Second CO ₂ condenser

174‧‧‧ pipeline

180‧‧‧refrigerator chiller

181‧‧‧ pipeline

182‧‧‧ pipeline

183‧‧‧ pipeline

184‧‧‧ Stripping Reboiler

185‧‧‧ heat exchanger

186‧‧‧CO ₂ pump

187‧‧‧CO ₂ product drum

188‧‧‧CO ₂ product pump

190‧‧‧Supply pipeline

191‧‧‧heater

192‧‧‧ first heat exchanger

193‧‧‧second heat exchanger

194‧‧‧ Flue gas expander

195‧‧‧ third heat exchanger

196‧‧‧fourth heat exchanger

197‧‧‧Second flue gas expander

198‧‧‧ fifth heat exchanger

210‧‧‧CO ₂ separation system

244‧‧‧ Flue gas compressor

250‧‧‧ Refrigeration system

251‧‧‧ refrigeration circuit

252‧‧‧Multi-stage refrigerant compressor

252'‧‧‧First compression stage

252"‧‧‧second compression stage

252'''‧‧‧ Third compression stage

254b‧‧‧ pipeline

254b1‧‧‧ pipeline

254b2‧‧‧ pipeline

255‧‧‧ flue gas duct

256‧‧‧ refrigerant compressor suction drum

257‧‧‧Refrigerant compressor suction drum

260‧‧‧ Flue gas cooler

261‧‧‧ pipeline

262‧‧‧Adsorption dryer

264‧‧‧First CO ₂ condenser

265‧‧‧First gas/liquid separator

266‧‧‧ pipeline

268‧‧‧ pipeline

270‧‧‧Second CO ₂ condenser

271‧‧‧Stripper

280‧‧‧refrigerator chiller

283‧‧‧ pipeline

285‧‧‧ heat exchanger

286‧‧‧CO ₂ pump

288‧‧‧CO ₂ product pump

291‧‧‧Regeneration gas heater

292a‧‧‧ heat exchanger

292b‧‧‧ heat exchanger

293‧‧‧ heat exchanger

294‧‧‧ Flue gas expander

295‧‧‧ pipeline

296‧‧‧ heat exchanger

297‧‧‧Second flue gas expander

298‧‧‧ heat exchanger

Reference is now made to the drawings, which are exemplary embodiments. FIG. 1 schematically illustrates an embodiment of a CO ₂ separation system.

Figure 2 illustrates an embodiment of the _separation system shown CO.

Figure 3 illustrates an embodiment of the _separation system shown CO.

10‧‧‧CO ₂ separation system

44‧‧‧Compressor

50‧‧‧ Refrigeration system

51‧‧‧ refrigeration circuit

52‧‧‧Multi-stage refrigerant compressor

52'‧‧‧First compression stage

52"‧‧‧second compression stage

52'''‧‧‧ Third compression stage

53‧‧‧Refrigerant condenser

55‧‧‧ Flue gas duct

56‧‧‧Refrigerant compressor suction drum

57‧‧‧Refrigerant compressor suction drum

60‧‧‧ Flue gas cooler

64‧‧‧First CO ₂ condenser

65‧‧‧First gas/liquid separator

66‧‧‧ pipeline

68‧‧‧ pipeline

70‧‧‧Second CO ₂ condenser

71‧‧‧Stripper

80‧‧‧refrigerator chiller

84‧‧‧ Stripping reboiler

85‧‧‧ heat exchanger

86‧‧‧CO ₂ pump

87‧‧‧CO ₂ product drum

88‧‧‧CO ₂ product pump

Claims (9)

A flue gas treatment system for removing CO ₂ from a flue gas stream, comprising a flue gas compressor, at least one flue gas adsorption dryer, and a refrigeration system for condensing carbon dioxide in the flue gas stream (CO ₂ ), the system comprises a refrigeration circuit (51) containing a refrigerant, the refrigeration circuit comprising: a multi-stage refrigerant compressor (52), a refrigerant condenser (53), a refrigerant chiller ( 80) a flue gas chiller (60), at least one condenser (70), and a stripper (71) allowing distillation; wherein the flue gas chiller is disposed in the flue gas compressor and the flue Between the gas adsorption dryers, and the flue gas adsorption dryer and the at least one condenser are disposed in series upstream of the stripper. The flue gas treatment system of claim 1, the system comprising another condenser (64) disposed in series upstream of the condenser (70). The flue gas treatment system of claim 1, the system further comprising a heat exchanger configured to cool at least a portion of the condensed refrigerant using a CO ₂ depleted flue gas from the second CO ₂ condenser . The flue gas treatment system of claim 1, the system further comprising a first heat exchanger configured to cool the condensed refrigerant using the CO ₂ depleted flue gas from the stripper At least a portion, a second heat exchanger configured to reheat the CO ₂ depleted flue gas from the first cryogen chiller using the warm flue gas from the flue gas compressor, a flue gas expander configured to expand the CO ₂ depleted reheated compressed flue gas from the first heat exchanger, the third heat exchanger configured to use the smoke from The CO ₂ depleted flue gas of the gas expander further cools the condensed refrigerant from the first refrigerant chiller, and the fourth heat exchanger is configured to use the flue gas The warm flue gas of the compressor reheats the CO ₂ depleted flue gas from the second heat exchanger, and the second flue gas expander is configured to be from the second heat exchanger The CO ₂ depleted reheating compresses the flue gas expansion and, as the case may be, a fifth heat exchanger configured to reheat from the The CO ₂ depleted flue gas of the third exchanger. The flue gas treatment system of claim 1, the system further comprising a first heat exchanger configured to cool the condensed refrigerant using the CO ₂ depleted flue gas from the stripper At least a portion of a second heat exchanger configured to reheat the CO ₂ depleted flue gas from the first heat exchanger using warm flue gas from the flue gas compressor, first a flue gas expander configured to expand the CO ₂ depleted reheated compressed flue gas from the second heat exchanger, the third heat exchanger configured to use from the flue The CO ₂ depleted flue gas of the gas expander further cools the condensed refrigerant from the first heat exchanger, and the second flue gas expander is configured to cause the second heat exchange The CO ₂ depleted reheated compressed flue gas expands, and a fourth heat exchanger configured to reheat the CO ₂ depleted flue gas from the third exchanger. The flue gas treatment system of claim 1, the system further comprising a selective catalytic reduction (SCR) unit for removing nitrogen oxides (NOx) from the flue gas stream and configuring the general flow direction with reference to the flue gas stream Downstream of the flue gas adsorption dryer. A method of condensing carbon dioxide (CO ₂ ) in a flue gas stream using an external refrigerant, the method comprising: a) compressing and at least partially condensing an external refrigerant to obtain a condensed external refrigerant, b) The condensed CO is distilled from the flue gas stream by at least partially vaporizing the condensed external refrigerant obtained in step a) to condense the flue gas stream to condense the CO ₂ in the flue gas stream, c) ₂ to separate, and d) to quench the condensed external refrigerant used for the refrigeration of step b) using the condensed CO ₂ separated in step c). The method of claim 7, wherein the external refrigerant is propane or propylene. The method of claim 7, wherein the external refrigerant is ammonia.