Amine reclaiming device and method; and a carbon capture system using same

Abstract

The amine reclaimer device comprises a stationary outer shell extending along a longitudinal, preferably horizontal axis. A heat exchanger is housed in the stationary outer shell and surrounds the longitudinal axis thereof. The heat exchanger comprises a hot side, adapted to rotate around the longitudinal axis of the stationary outer shell. The reclaimer device further comprises a liquid feed line, adapted to feed a liquid flow centrally to the heat exchanger. The liquid flow contains water, amine and chemical species generated by amine degradation. The reclaimer device further comprises a liquid removal duct, adapted to remove liquid accumulating on the inner surface of the stationary outer shall. The reclaimer device further comprises a vapor removal duct adapted to remove vapor from the stationary outer shell. Also disclosed herein is a carbon capture system including the reclaimer device, and an amine reclaimer method.

Description

AMINE RECLAIMING DEVICE AND METHOD; AND A CARBON CAPTURE SYSTEM USING SAMEDESCRIPTIONTECHNICAL FIELD

[0001] The present disclosure relates generally to carbon capture technology and more generally to gas treating. Embodiments disclosed herein, specifically relate to methods and devices for reclaiming amines and removing amine degradation products from an absorption solution in carbon capture systems.BACKGROUND ART

[0002] Carbon dioxide (CO2) is a greenhouse gas which is believed to be one of the major contributors to global warming and climate changes. Carbon dioxide is generated by several industrial processes, where thermal power is generated by combustion of fossil fuels, such as natural gas and oil.

[0003] Carbon capture and storage (in short CCS) is a technology effective to make deep cuts in greenhouse gas emissions. Post combustion capture (in short PCC) is a process which uses an aqueous absorption solution (herein referred to also as solvent) containing compounds such as amines, ammonia, potassium salts and the like, to capture carbon dioxide from flue gas generated by combustion of fossil fuel

[0004] The solvent contacts CCh-rich flue gas in an absorber and causes carbon dioxide to be trapped in the solvent. C Ch-rich solvent is then transferred to a regenerator, where carbon dioxide is removed and delivered to a carbon dioxide recovery line for further processing, while the CCh-lean solvent obtained by removing carbon dioxide therefrom is recirculated towards the absorber. The CC -lean flue gas is released in the environment.

[0005] Several carbon capture systems use amine-based solvents to capture carbon dioxide from the flue gas.

[0006] Amine based solvents can use a variety of amines, i.e. derivatives of ammonia in which one or more of the hydrogen atoms have been replaced by an alkyl or arylgroup or an alcohol. Amines are classified as primary, secondary or tertiary depending on whether one, two or three of the hydrogen atoms of the amine have been replaced by a respective organic group. Some of the most commonly used amines in carbon dioxide capture are monoethanolamine (MEA), methyldiethanolamine (MDEA), 2- amino-2-methylpropanol (AMP), piperazine (PZ), digycolamine (DGA), diethanolamine (DEA), di-isopropanolamine (DIP A), as well as combinations thereof. The list above shall be understood as exemplary and non-limitative of the possible amine derivatives which can be used in amine-based carbon capture systems.

[0007] The amines used in CCE-capture plants are recycled, in that CCE-rich solvent delivered by an absorber, where the solvent has reacted with the flue gas and removed carbon dioxide therefrom, is treated in a carbon dioxide stripper, to remove carbon dioxide and recover CCE-lean solvent containing amines, which is recycled towards the absorber.

[0008] However, a minor potion of the amines escapes from the absorber and is entrained by the CCE-lean flue gas. To prevent amine release in the environment, flue gas is washed with water before releasing in the atmosphere. A further portion of amines also degrades in the process, thus generating degradation products, which must be removed from the solvent to prevent accumulation thereof in the system. The degradation products can be generated by corrosive reactions.

[0009] In general, there are different degradation processes which are responsible for production of amine degradation products accumulating in the solvent which circulates in a carbon capture system, and more specifically: oxidative degeneration, which mainly takes place in the absorber; thermal degradation, which takes place mainly in the carbon dioxide stripper.

[0010] To remove chemical species generated by amine degradation and to limit the loss of amine from the carbon capture plant, it is known to process CCE-lean solvent, extracted from the bottom of the carbon dioxide stripper or taken as a side stream from the solvent inlet line of the absorber, as an example, in an amine reclaimer unit. The solvent processed in the reclaimer unit contains water, amine(s) and degradation products. According to the current art, reclaimers usually comprise a kettle-type heat exchanger, aka kettle reboiler or kettle boiler, wherein the solvent is fed in the shell ofthe kettle boiler and heated by heat exchange with a tube bundle in which a heating medium, i.e. a heat transfer fluid, circulates. Water and amines are vaporized, while degradation products remain in the liquid. The liquid remaining in the kettle boiler is gradually removed and replaced by a continuous flow of solvent from the carbon dioxide stripper or the return CCh-lean solvent duct. The liquid which is removed from the kettle boiler contains a high concentration of degradation products in a water solution, which must be disposed of. An alternative to a kettle reboiler is a thermosyphon boiler combined with a tank for liquid, but the challenges are much the same, and the liquid inventory remains high.

[0011] Reclaimers based on kettle boiler technology suffer from several drawbacks. They require a large amount of thermal energy to heat and vaporize water (which is more volatile) and amines (which are less volatile than water). The resulting waste liquid removed from the kettle boiler still contains a large amount of water. This represents a considerable volume which must be disposed of. Moreover, kettle boilers require a high liquid inventory, i.e. a nearly constant, high level of liquid must be maintained in the kettle boiler, to keep the tube bundle of the heat exchanger submerged in liquid, which is a pre-condition for a correct operation of the kettle boiler. To achieve a high amine concentration in the liquid, large amounts of water need to be evaporated, which implies a high consumption of energy per unit of amine recovered.

[0012] A more efficient amine reclaiming device and method, aimed at alleviating the drawbacks and disadvantages of the current art, would be desirable.SUMMARY

[0013] According to a first aspect, disclosed herein is an amine reclaimer device, which comprises a stationary outer shell extending along a longitudinal, preferably horizontal axis. A heat exchanger is housed in the stationary outer shell and surrounds the longitudinal axis of the outer shell. The heat exchanger comprises a hot side, which can include a tube bundle for circulation of a heat transfer fluid adapted to transfer fluid to the heat exchanger. The hot side of the heat exchanger is adapted to rotate around the longitudinal axis of the stationary outer shell. The reclaimer device further comprises a liquid feed line, adapted to feed a liquid flow centrally to the heat exchanger. The liquid flow contains water, amine and chemical species generated byamine degradation. The reclaimer device further comprises a liquid removal duct, adapted to remove liquid accumulating on the inner surface of the stationary outer shall. The reclaimer device further comprises a vapor removal duct adapted to remove vapor from the stationary outer shell.

[0014] In some embodiments, the reclaimer device further comprises a recycle line adapted to recycle liquid from the liquid removal duct and reinject recycled liquid centrally in the heat exchanger.

[0015] The vapor removal duct can be is fluidly coupled with a central volume surrounding the liquid feed line, and more precisely a central volume between the liquid feed line and the and the hot side of the heat exchanger, for instance a tube bundle forming the hot side of the heat exchanger.

[0016] According to another aspect, disclosed herein is a carbon capture system comprising an amine reclaimer device as outlined above.

[0017] Further features of the amine reclaimer device and of the carbon capture system including the amine reclaimer device are described below and are set forth in the appended claims.

[0018] According to yet a further aspect, disclosed herein is a method for reclaiming amines and removing amine degradation products from an absorption solution in a carbon capture system or the like. The method comprising the following steps: supplying a liquid to a center of a heat exchanger, wherein the heat exchanger comprises a hot side rotating around a rotation axis, the liquid containing amines, water and chemical species generated by degradation of amines; rotating the hot side of the heat exchanger around the rotation axis; centrifugally projecting liquid from the rotating hot side of the heat exchanger against an inner surface of an outer stationary shell surrounding the heat exchanger; removing a vapor stream from the stationary shell, the vapor stream containing reclaimed amines and steam; removing a liquid from the stationary shell, the liquid containing amine degradation products.

[0019] Further features and embodiments of the method are described below and setforth in the appended claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Reference is now made briefly to the accompanying drawings, in which: Fig.l illustrates a schematic of a CO2 capture system;Fig.2 illustrates a sectional view of a reclaimer device according to the present disclosure;Fig.3 illustrates a schematic cross section according to line III-III of Fig.2; andFig.4 illustrates an arrangement with two reclaimer devices in sequence.DETAILED DESCRIPTION

[0021] Fig. 1 shows a schematic of an amine- based CO2 capture system 1 adapted to remove carbon dioxide from a gaseous stream. These installations are known to those skilled in the art and only the main components thereof will be recalled herein, for a better understanding of the subject of the present disclosure.

[0022] In the embodiment of Fig.1, the system 1 receives exhaust flue gas containing carbon dioxide, which must be removed before discharging the exhaust flue gas into the atmosphere. The system 1 comprises a supply line 3 through which exhaust flue gas is fed into the system 1. A cooler 5 can be positioned along the supply line 3, to cool the flue gas before treatment in the system 1.

[0023] The system 1 further comprises: an absorber 7; a carbon dioxide stripper 9; a CCh-rich absorbent solution line 11, fluidly coupling outlet 7.1 of the absorber 7 with an inlet 9.1 of the carbon dioxide stripper 9 to transfer CCE-rich absorbent solution from the absorber 7 to the carbon dioxide stripper 9; and a CCE-lean absorbent line 13 fluidly coupling an outlet 9.2 of the carbon dioxide stripper 9 with an inlet 7.2 to the absorber 7 to return CCE-lean absorbent solution from the carbon dioxide stripper 9 to the absorber 7. The CCE-rich absorbent solution line and the CCE-lean absorbent solution line extend through a heat exchanger 15, where heat is transferred from the CO2- rich absorbent solution to the CCE-lean absorbent solution.

[0024] The carbon dioxide stripper 9 is combined with an overhead condenser 17, areboiler 19 and an amine reclaimer device 21, which will be described in more detail below.

[0025] As known to those skilled in the art, the system 1 schematically shown in Fig.1 operates as follows. A gaseous stream containing carbon dioxide, for example flue gas from a gas turbine, or any other carbon dioxide producing device or process, is fed to the absorber 7, where the flue gas is contacted with a CO2-lean absorbent solution delivered to the absorber 7 through the CO2-lean absorbent line 13. In an amine-based CO2 capture system as disclosed herein, the absorbent solution contains one or more amines, as listed above. For the sake of simplicity, in the present disclosure reference will shortly be made specifically to monoethanolamine (MEA) only, but it shall be understood that this amine is only used as a non-limiting example of an active chemical component adapted to absorb carbon dioxide from the flue gas and release carbon dioxide in the carbon dioxide stripper.

[0026] The amines contained in the absorbent solution react with carbon dioxide contained in the flue gas and form intermediate chemical species, referred to as carbamates. The resulting CCh-rich absorbent solution is transferred through C Ch-rich line 11 to the carbon dioxide stripper 9, wherein the carbamates are converted back into amines under release of carbon dioxide. The reaction in the carbon dioxide stripper requires heat, which is supplied by the reboiler 19, for instance a kettle reboiler supplied with steam.

[0027] The resulting CCh-lean absorbent solution is returned to the absorber 7 through the CO2-lean absorbent line 13, while a flow of carbon dioxide and steam is collected in the overhead condenser 17, where water is condensed and returned to the system, while carbon dioxide is removed through a CCh-removal line 23, along which a liquid / gas separator 25 can be positioned for removing residual liquid from the carbon dioxide stream.

[0028] A main stream of liquid absorbent solution is recirculated from the bottom of the carbon dioxide stripper 9 through the reboiler 19. In the embodiment of Fig. 1, a fraction of the liquid absorbent solution removed from the bottom of the carbon dioxide stripper 9 is fed through the amine reclaimer device 21, through which amine degradation products are removed from the system. Reference number 55 in Fig. lrepresents a liquid feed line which delivers the liquid absorbent solution from the bottom of the carbon dioxide stripper 9 to the amine reclaimer device. Vapor will be generated in the amine reclaimer wheel 21, as will be described in detail below. The vapor (i.e. the gaseous phase generated in the reclaimer wheel 21) is returned to the carbon dioxide stripper 9 through a return duct 22.

[0029] While in Fig.l the CCh-lean absorbent solution to be delivered to the amine reclaimer device 21 is drawn from the bottom of the carbon dioxide stripper 9, in other embodiments, a flow of CCh-lean absorbent solution can be removed as feed to the amine reclaimer device 21 from the CCh-lean absorbent line 13, for instance downstream of the heat exchanger 15, as shown by dotted line 30.

[0030] To compensate for the reduction of amine content in the absorbent solution, due to degradation, the system 1 can comprise an amine storage unit 27, which supplies amines to the circuit to maintain a correct concentration of amines in the absorbent solution circulating in the system.

[0031] With continuing reference to Fig. l, a novel structure of the amine reclaimer device 21 will be described with reference to Figs. 2 and 3. The amine reclaimer device 21 comprises a stationary outer shell 41 which extends along a longitudinal axis A-A. In use, the longitudinal axis A-A is positioned horizontally, i.e. is oriented in a direction orthogonal to the direction of the force of gravity.

[0032] The stationary outer shell 41 can be substantially cylindrical and can have two opposite heads 41 A, 4 IB. The stationary outer shell 41 further comprises an inner surface 41.1 and an outer surface 41.2.

[0033] A heat exchanger 43 is housed in the stationary outer shell 41. The heat exchanger 43 envelops the longitudinal axis A-A of the stationary outer shell and rotates therearound, see arrow f43 in Fig.3. More specifically, the heat exchanger actually comprises a part forming the hot side of the heat exchanger, in which a heat transfer fluid circulates. The part of the heat exchanger which forms the hot side thereof rotates around the longitudinal axis A-A. In the exemplary embodiment of Fig.2 the heat exchanger 43, and specifically the part thereof which forms the hot side of the heat exchanger 43, comprises a tube bundle 45, including a plurality of longitudinallyextending tubes 45A. The tube bundle surrounds a central volume 56. The inner volume of the tube bundle, i.e., of the tubes 45A, represents the hot side of the heat exchanger 43. The cold side of the heat exchanger is formed by the inner volume of the outer shell 41, which surrounds the tube bundle 45. Since the tube bundle 45 of the heat exchanger 43 rotates around axis A-A, the heat exchanger 43 is shortly defined as being a rotating heat exchanger, adapted to rotate around the axis A-A, even though the cold side of the heat exchanger does not actually rotate. Here below, the term “heat exchanger” is also referred simply to the rotary part thereof, which forms the hot side of the heat exchanger 43.

[0034] The tubes 45A of the tube bundle 45 can be parallel to the longitudinal axis A-A of the stationary outer shell 41, i.e. to the rotation axis of the heat exchanger 43. The rotating heat exchanger 43 further comprises opposite first head 47 and 49. The head 47 is fluidly coupled to an infeed rotary joint 51, wherethrough a heat transfer fluid, for instance steam, is fed through the head 47 and through the tubes 45A (see arrows S in Fig.2).

[0035] The opposite head 49 is fluidly coupled with an outlet rotary joint 53, wherethrough spent heat transfer fluid, for instance spent steam and / or condensate is removed from the rotating heat exchanger 43.

[0036] In this embodiment, the heat exchanger, and more precisely the rotary hot part thereof, i.e. the hot side thereof, including the tube bundle 45, is therefore supported for rotation at opposite ends and the heat transfer medium which flow in the tube bundle 45 enters at one end and exits at the opposite end of the heat exchanger 43. In other embodiments, not shown, the tube bundle 45 can be supported in a cantilever fashion, i.e. can overhang from one rotary support and the heat transfer medium can enter and exit the tube bundle 45 from the same side.

[0037] The amine reclaimer device 21 further comprises a liquid feed line 55, which is positioned in a central position inside the heat exchanger 43, and more precisely in a central position inside the tube bundle 45, and extends longitudinally through the heat exchanger 43. The liquid feed line 55 can be stationary and can be coaxial with the rotation axis A-A, i.e. the longitudinal axis of the stationary outer shell 41. The liquid feed line 55 can preferably extend through the full axial length of the heatexchanger 43. Sufficient room is left between the liquid feed line 55 and the tube bundle 45 for the purposes described below.

[0038] The liquid feed line 55 is adapted to feed a liquid flow centrally in the heat exchanger 43, i.e. in a volume 56 surrounded by the tube bundle 45. The liquid flow is delivered from the carbon dioxide stripper 9 or from the CCh-lean absorbent line 13, for instance. The liquid flow contains water, amines, and amine degradation products, i.e. chemical species generated by chemical or thermal degradation of the amines contained in the absorbent solution.

[0039] The liquid feed line 55 can include a plurality of dispensing ports 55A, along the longitudinal extension thereof. The dispensing ports 55A can be distributed angularly around the longitudinal axis A-A. Through the dispensing ports 55A the liquid feed line 55 is fluidly coupled with the central volume 56, surrounded by the tube bundle 45 of the heat exchanger 43.

[0040] The amine reclaimer device 21 further comprises a liquid removal duct 59, which is configured to remove liquid from the stationary outer shell. At least a part of the removed liquid can be recycled into the stationary outer shell and more specifically into the central volume 56 surrounded by the tube bundle 45 of the heat exchanger 43. The liquid removal duct 59 can for instance be fluidly coupled with the central volume 56 through a recycle line 59A. The recycle line can extend parallel to the liquid feed line 55 as schematically shown in the cross-section of Fig.3, or can be fluidly coupled to the liquid feed line 55, as shown in Fig.2-

[0041] The liquid removal duct 59 can be combined with a pressure generating device, adapted to pressurize liquid removed from the stationary outer shell. In the exemplary embodiment of Fig.2, the liquid removal duct is fluidly coupled with a plurality of Pitot tubes 61, which are positioned adjacent to the inner surface 41.1 of the stationary outer shell 41. In embodiments, a plurality of Pitot tubes 61 are distributed, preferably in a uniform manner, along the longitudinal extension of the stationary outer shell 41.

[0042] As will be explained in more detail below, the Pitot tubes 61 are aimed at converting kinetic energy of the fluid collecting on the inner surface 41.1 of thestationary outer shell 41 into pressure, to facilitate removal of the liquid from the interior of the stationary outer shell 41.

[0043] The liquid removal duct 59 is fluidly coupled with a bleed duct 65, wherethrough a flow of liquid containing concentrated amine degradation products can be continuously or intermittently removed. A control valve 67 can be positioned along the bleed duct 65 to control the flow of liquid removed from the amine reclaimer device 21.

[0044] The amine reclaimer device 21 described so far operates as follows.

[0045] CCh-lean absorbent solution from the carbon dioxide stripper 9 is delivered to the amine reclaimer device 21 and fed therein through the liquid feed line 55. Through the dispensing ports 55A the liquid is distributed on the tube bundle 45 of the heat exchanger 43, while the tube bundle 45 of the heat exchanger 43 is maintained in fast rotation around the rotation axis A-A by a driver, for instance an electric motor, not shown. Steam, or another heat transfer fluid, flows through the tubes 45 of the tube bundle 45A, and transfers heat to the liquid which is distributed on the outer surface of the tubes 45.

[0046] Part of the water and amines contained in the liquid, which percolates on the rotating tube bundle 45 heat exchanger 43, evaporate while the remaining liquid is projected by centrifugal force from the rotating tube bundle 45 against the inner surface 41.1 of the stationary outer shell 41.

[0047] The vapor stream generated by evaporation collects in the central volume 56 surrounded by the tube bundle 45 of the heat exchanger 43 and can be removed through a vapor removal duct 68 fluidly coupled with a rotary joint 69, which can be positioned on one or both pins 48 of the rotary tube bundle 45 of the heat exchanger 43. The vapor stream is returned to the carbon dioxide stripper 9, for instance. In some embodiments, the vapor stream from the amine reclaimer unit 21 is routed back to the bottom of the carbon dioxide stripper 9 thus relieving the reboiler duty.

[0048] The manner of extracting the vapor stream from the amine reclaimer device 21 can be different. For instance, if the rotary tube bundle 45 is supported in a cantilever fashion, i.e. is supported only on one axial end thereof, removal of the vapor streamcan be through a stationary duct.

[0049] The film of liquid collecting along the inner surface 41.1 of the stationary outer shell 41 has a tangential speed in the direction of rotation (arrow f43 in Fig.3) of the tube bundle 45 of the heat exchanger 43. The liquid which accumulates on the inner surface 41.1 of the stationary outer shell 41 is collected by the Pitot tubes 61, in which the kinetic energy of the liquid is converted into pressure, such that the flow through the liquid removal duct 59 is facilitated. If the control valve 67 is closed, the entire liquid flow entering the liquid removal duct 59 is recycled through the recycle line 59A towards the central volume 56 surrounded by the tube bundle 45 of the heat exchanger 43 and is therefore subject to further evaporation of amines and water contained therein.

[0050] If the control valve 67 is open, a controlled amount of liquid collecting on the inner surface 41.1 of the stationary outer shell 41 is removed through the bleed line 65. during the process.

[0051] The liquid flowing through the amine reclaimer device 21 can be processed in a continuous, semi-continuous or batch mode.

[0052] In a continuous operation mode, the control valve 67 is open and liquid containing a concentrated amount of amine degradation products is continuously removed through the bleed line 65, while fresh CCh-lean absorbent solution is continuously fed through the liquid feed line 55. The control valve 67 can be controlled such that the flowrate of the liquid removed through the bleed line 65 can be adjusted based on the percentage of liquid recycled through the recycle line 59A. The lower the flowrate through the bleed line 65 compared with the incoming flowrate of CCh-lean absorbent solution, the longer the residence time of the liquid in the amine reclaimer device 21. In some embodiments, even in continuous operation, the valve 67 may be open / shut intermittently. For example, the system can operate within given liquid levels.

[0053] In an intermittent mode of operation, the control valve 67 can be opened intermittently to discharge liquid containing concentrated amine degradation products from the stationary outer shell 41, while fresh CCh-lean absorbent solution can be fed continuously or intermittently through the liquid feed line 55. The time span betweensuccessive bleedings of liquid from the amine reclaimer can be changed to adjust the residence time of the liquid in the amine reclaimer device 21.

[0054] In a batch mode of operation, a predetermined amount of fresh CCh-lean absorbent solution is loaded in the amine reclaimer device 21 and processed therein by continuously recycling the liquid which collects on the inner surface 41.1 of the stationary outer shell 41 , until potentially all the amines contained in the liquid are recovered. The resulting liquid, wherefrom most of the water has been removed by evaporation, is discharged at the end of the process by opening the control valve 67 in the bleed line 65. Fresh CCh-lean absorbent solution is then fed into the amine reclaimer device for a next cycle. The vapor phase will, however, be continuously removed from the amine reclaimer device 21.

[0055] In some embodiments, e.g. depending upon the volatility of the amines used in the system, the stationary outer shell 41 can be maintained in a depressurized condition, i.e. with a reduced pressure inside the shell, thus facilitating the evaporation of heavy amines without the need to operate at prohibitively high temperatures.

[0056] The CCh-lean absorbent solution fed to the amine reclaiming device 21 inevitably contains an amount of the valuable chemical used in the capture of the CO2. Such as monoethanolamine or other amines. The amines could be in at least three forms in the stream fed to the amine reclaimer device, namely: free amine molecules, amines bound with carbon dioxide in the form of carbamates, and as a component in so-called heat stable salts.

[0057] The heat stable salts referred to comprise a number of salts of inorganic and organic acids. Formic and acetic acid salts are typical amongst the organic. Inorganic salts are generally attributed to the presence of SOXand NO2 in the flue gas being treated in the carbon capture system 1.

[0058] The CCh-lean absorbent solution fed to the amine reclaimer device 21 can be treated with a strong alkali prior to evaporation in heat exchanger 43. For instance, sodium hydroxide (NaOH) can be used as an alkali for pre-treatment or con-current treatment. Sodium is a much cheaper chemical than the amines used in the carbon capture process. This is why adding NaOH to recover amines from the CO2-leanabsorbent solution processed through the amine reclaimer device 21 is economically beneficial. In Fig.2 reference 71 schematically indicates the addition of sodium hydroxide to the incoming stream of CCh-lean absorbent solution being treated in the amine reclaimer device 21.

[0059] In some embodiments, the amine reclaimer device 21 can comprise a multistage configuration. An embodiment with a two-stage configuration is schematically shown in Fig.4. A first amine reclaimer unit is shown at 21A and a second amine reclaimer unit is shown at 21B. Each amine reclaimer unit 21 A, 21B can be configured as shown in Fig.2. The first, i.e. upstream, amine reclaimer unit 21 A is fluidly coupled with the carbon dioxide stripper 9 through a liquid feed line 55, which supplies CO2- lean absorbent solution to the first amine reclaimer unit 21A. Reference number 59’ designates a liquid removal duct through which liquid containing concentrated amine degradation products is removed from the stationary outer shell of the first amine reclaimer unit 21A and delivers the removed liquid partly to a recycle line 59A’ and partly through a control valve 67’ and a bleed line 65’ to the second amine reclaimer unit 2 IB. Additional water can be supplied to the second amine reclaimer unit 2 IB through a water supply line 30. The second amine reclaimer unit 2 IB comprises a liquid removal duct 59 which recycles through a recycle line 59A the liquid back to the center of the heat exchanger of the second amine reclaimer unit 2 IB, or alternatively discharges liquid containing concentrated amine degradation products through a bleed duct 65 and control valve 67.

[0060] Operation of the two-stage amine reclaimer device 21 of Fig.4 can operate in a continuous, semi-continuous or batch mode as described above. Preferably, the operation is a continuous operation, since the liquid removed from the first amine reclaimer unit 21 A is gradually transferred to the second amine reclaimer unit 21B while fresh CO2-lean absorption solution bleeding from the carbon dioxide stripper 9 is fed to the liquid feed line 55, and concentrated amine degradation products are continuously removed from the second amine reclaimer unit 2 IB in a controlled manner through control valve 67 and bleed duct 65.

[0061] In some embodiments, as schematically shown in Fig.4, sodium hydroxide or another strong alkali can be added to the amine reclaimer device 21, preferably to thefirst amine reclaimer unit 21 A.

[0062] Exemplary embodiments have been disclosed above and illustrated in the accompanying drawings. It will be understood by those skilled in the art that various changes, omissions and additions may be made to that which is specifically disclosed herein without departing from the scope of the invention as defined in the following claims.

Claims

CLAIMS1. An amine reclaimer device (21), comprising: a stationary outer shell (41) extending along a longitudinal axis (A-A); a heat exchanger (43) surrounding the longitudinal axis (A-A) of the outer shell (41) and comprising a hot side (45, 45A) adapted to rotate around the longitudinal axis (A-A); wherein the stationary outer shell (41) has an inner surface (41.1) which surrounds the heat exchanger (43); a liquid feed line (55), adapted to feed a liquid flow centrally to the heat exchanger (43); wherein the liquid flow contains water, amine and chemical species generated by amine degradation; a liquid removal duct (59), adapted to remove liquid accumulating on the inner surface of the stationary outer shall; and a vapor removal duct (68) adapted to remove vapor from the stationary outer shell (41).

2. The amine reclaimer device (21) of claim 1, further comprising a recycle line (59A) adapted to recycle liquid from the liquid removal duct and reinject recycled liquid centrally in the heat exchanger (43).

3. The amine reclaimer device (21) of claim 1 or 2, wherein the vapor removal duct (68) is fluidly coupled with a central volume (56) surrounding the liquid feed line (55).

4. The amine reclaimer device (21) of claim 3, wherein the vapor removal duct (68) is fluidly coupled with a rotary joint (69).

5. The amine reclaimer device (21) of any one of the preceding claims, wherein the liquid feed line (55) is fluidly coupled with a central volume (56) surrounded by the hot side of the heat exchanger (43) and surrounding the liquid feed line (55).

6. The amine reclaimer device (21) of claim 5, wherein the liquid feed line (55) extends longitudinally in the central volume (56) surrounded by the hot side of the heat exchanger (43) and comprises a plurality of dispensing ports (55A) distributed along a longitudinal extension thereof.

7. The amine reclaimer device (21) of claim 5 or 6, when depending on claim 2, wherein the recycle line (59A) is fluidly coupled with the central volume surrounded by the hot side of the heat exchanger (43).

8. The amine reclaimer device (21) of claim 7, wherein the recycle line (59A) is fluidly coupled with the liquid feed line (55).

9. The amine reclaimer device (21) of any one of the preceding claims, wherein the liquid removal duct (59) is combined with a pressure generating device (61), adapted to pressurize liquid removed from the stationary outer shell (41).

10. The amine reclaimer device (21) of claim 9, wherein the pressure generating device (61) is adapted to convert kinetic energy from a liquid collecting at the inner surface (41.1) of the outer shell (41), into pressure.

11. The amine reclaimer device (21) of any one of the preceding claims, wherein the hot side (45, 45A) of the heat exchanger (43) is adapted to circulate a heat transfer medium in heat exchange with a cold side of the heat exchanger, the cold side comprising an inner volume of the outer shell (41).

12. The amine reclaimer device (21) of claim 11, wherein the hot side (45, 45A) of the heat exchanger (43) comprises a tube bundle (45) surrounding the liquid feed line (55).

13. The amine reclaimer device of claim 12, when depending upon any one of claims 3 to 8, wherein the tube bundle (45) surrounds said central volume (56).

14. The amine reclaimer device (21) of claim 13, wherein the tube bundle (45) extends in the direction of the longitudinal axis (A-A) of the stationary shell (41); wherein the tube bundle (45) comprises a plurality of longitudinal tubes (45A) extending parallel to the liquid feed line (55).

15. The amine reclaimer device (21) of claim 14, wherein each longitudinal tube comprises an inlet end fluidly coupled with an infeed rotary joint (51), and an outlet end fluidly coupled with an outfeed rotary joint (53).

16. The amine reclaimer device (21) of claim 15, wherein the inlet endand the outlet end of the longitudinal tubes (45 A) are arranged at opposite ends of the heat exchanger (43) or at the same end of the heat exchanger (43).

17. The amine reclaimer device (21) of any one of the preceding claims, wherein the amine reclaimer device is configured to rotate around a horizontal longitudinal axis (A-A).

18. A carbon capture system (1), comprising: an absorber (7) comprising: an inlet (7.2) adapted to receive a CCh-lean absorption solution containing water and amine; an outlet (7.1) adapted to release a CCh-rich absorption solution; a carbon dioxide stripper (9), adapted to receive a CCh-rich absorption solution from the absorber (7), and to return a CCh-lean absorption solution to the absorber (7); a reboiler (19), adapted to supply thermal energy to the carbon dioxide stripper (9) to promote CCh-release from the C Ch-rich absorption solution; a reclaimer device (21) according to any one of the preceding claims, fluidly coupled adapted to receive CCh-lean absorption solution containing amine and amine degradation products, and separate amine from amine degradation products.

19. The system of claim 18, wherein the liquid feed line (55) of the reclaimer device (21) is fluidly coupled with at least one of: the carbon dioxide stripper (9), the reboiler (19), and a fluid duct containing a hot CCh-lean absorption solution to receive a liquid containing ammine therefrom.

20. The system of claim 18 or 19, wherein the reclaimer device is fluidly coupled with the carbon dioxide stripper (19) to return a gaseous phase to the stripper.

21. A method for reclaiming amines and removing amine degradation products from an absorption solution; the method comprising the following steps: supplying a liquid to a center of a heat exchanger (43), wherein the heat exchanger comprises a hot side (45, 45A) rotating around a rotation axis (A-A), the liquid containing amines, water and chemical species generated by degradation of amines; rotating the hot side (45, 45A) of the heat exchanger (43) around the rotation axis (A-A);centrifugally projecting liquid from the rotating hot side (45, 45 A) of the heat exchanger (43) against an inner surface (41A) of an outer stationary shell (41) surrounding the heat exchanger (43); removing a vapor stream from the stationary shell (41), the vapor stream con- taining reclaimed amines and steam; removing a liquid from the stationary shell (41), the liquid containing amine degradation products.

22. The method of claim 21, further comprising the step of recycling at least a fraction of the liquid removed from the stationary shell (41) to the heat ex- changer (43).

23. The method of claim 22, wherein the step of recycling at least a fraction of the liquid removed from the stationary shell (41) to the heat exchanger (43) comprises feeding the recycled liquid into the center of the heat exchanger (43).

24. The method of claim 22 or 23, further comprising the step of pres- surizing the recycled fraction of liquid by converting kinetic energy thereof into pressure.

25. The method of any one of claims 21 to 24, wherein the pressure in the stationary shell (41) is maintained below ambient pressure.

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