System and method for co 2 capture

Abstract

A mixed salt process system and process for removing CO2 from a CO2-containing gas stream are disclosed. The system comprises an absorber configured to treat a CO2- containing gas steam with two or more mixtures of different solvents made from a CO2-lean solution and a CO2-rich recirculation solution. The absorber is configured to receive separate portions of the CO2-lean solution at different absorption stages, and configured to receive separate portions of the CO2-rich recirculation solution at different absorption stages. The absorber can have a single CO2-rich solution outlet and the system can further include a regenerator having a single CO2-lean solution outlet.

Description

71CCS-510953-WO-2 (BHI0565PCT)SYSTEM AND METHOD FOR CO2CAPTURECROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Italian Application No. 102024000020011, filed on September 9, 2024, which is incorporated herein by reference in its entirety.BACKGROUND

[0002] Carbon dioxide is a primary driver of global climate change; therefore, it is critical to reduce its emissions. A mixed salt process (MSP) uses aqueous mixtures of potassium carbonate and ammonium salts as solvents and captures carbon dioxide (CO2) from a gas stream by dissolving CO2 in the solvent forming bicarbonate ions and / or carbonate ions. Since the current MSP process and system may have a high operating cost, there remains a need in the art for an energy efficient process and system for CO2 capture.SUMMARY

[0003] A mixed salt process CO2 capture system comprising: an absorber configured to treat a CCh-conlaining gas steam with two or more mixtures of different solvents made from a CCh-lean solution and a CCh-rich recirculation solution, the absorber having a gas inlet for introducing the CCh-conlaining gas stream into the absorber; a gas outlet for removing a treated gas stream from the absorber; a plurality of absorption stages; and a single CCh-rich solution outlet configured for removal of a CCh-rich solution from the absorber, the absorber being configured to receive a first portion of a CCh-lean solution and optionally a second portion of the CCh-lean solution at different absorption stages, and configured to receive a first portion of a CCh-rich recirculation solution and optionally a second portion of a CCh-rich recirculation solution at different absorption stages; the CCh-rich solution outlet is in fluid communication with a CCh-rich solution outlet system comprising a means for dividing the CCh-rich solution removed from the absorber into a CCh-rich regeneration solution and a CCh-rich recirculation solution and directing the CCh-rich regeneration solution to a regeneration system and directing the CCh-rich recirculation solution to a recirculation system; the recirculation system comprising a pump and a means for temperature and flow control of the CCh-rich recirculation solution and further comprising a means for dividing the CCh-rich recirculation solution; and a CCh-lean solution feeding71CCS-510953-WO-2 (BHI0565PCT) system comprising a means for temperature and flow control of the CC -lean solution.

[0004] A mixed salt process of removing CO2 from a CC -containing gas stream, the process comprising: introducing a CCh-containing gas stream into an absorber, the absorber having a plurality of absorption stages, and configured to receive a first portion of a CCh-lean solution and a second portion of the CCh-lean solution at different absorption stages; contacting the CCh-containing gas stream with the first portion of the CCh-lean solution and the second portion of the CCh-lean solution, generating a treated gas stream and a CCh-rich solution; dividing the CCh-rich solution into a CCh-rich regeneration solution and a CCh-rich recirculation solution; recirculating a first portion of the CCh-rich recirculation solution and a second portion of the CCh-rich recirculation solution to different absorption stages; and passing the CCh-rich regeneration solution after heat exchange to a regenerator, the regenerator producing a CO2 gas and a CCh-depleted solution as the CCh-lean solution introduced to the absorber after heat exchange.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

[0006] FIG. 1 is a diagram illustrating various streams introduced and taken from an absorber;

[0007] FIG. 2 is a diagram illustrating an absorber with different stages;

[0008] FIG. 3 is a simplified scheme illustrating a system and process for removing CO2 from a CO2-containing gas stream;

[0009] FIG. 4A is a graph of CO2 capture rate (CCR) and ammonia slip (kilograms per second, kg / s) as a function of the recirculation fraction;

[0010] FIG. 4B is a graph of CCR and ammonia slip (kg / s) as a function of the recirculation absorber inlet temperature (°C); and

[0011] FIG. 5 shows the effects of recirculation inlet position on CCR and ammonia slip.DETAILED DESCRIPTION

[0012] A mixed salt process system and process for removing CO2 from a CO2- containing gas stream are described. Unlike the configurations with two CO2-lean streams having different CO2 loadings because they are taken from two different points of a regenerator and two CO2-rich streams having different CO2 loadings because they are taken71CCS-510953-WO-2 (BHI0565PCT) from two different points of an absorber, or the configurations with two CCh-lean streams taken from two different points of a regenerator and one CCh-rich stream taken from the bottom of an absorber, the system and process described herein operate with a single rich flow taken from an absorber and a single lean flow taken from a regenerator.

[0013] The absorber comprises a gas inlet for introducing the CCh-containing gas stream into the absorber and a gas outlet for removing a treated gas stream from the absorber. The absorber further comprises a plurality of absorption stages and is configured to receive a first portion of a CCh-lean solution and optionally a second portion of the CCh-lean solution at different absorption stages and configured to receive a first portion of a CCh-rich recirculation solution and optionally a second portion of a CCh-rich recirculation solution at different absorption stages. In a particular aspect, the absorber further comprises a plurality of absorption stages and is configured to receive a first portion of a CCh-lean solution and a second portion of the CCh-lean solution at different absorption stages and configured to receive a first portion of a CCh-rich recirculation solution and a second portion of a CCh-rich recirculation solution at different absorption stages.

[0014] The absorber comprises a single CCh-rich solution outlet in fluid communication with a CCh-rich solution outlet system comprising a means for dividing the CCh-rich solution removed from the absorber into a CCh-rich regeneration solution and a CCh-rich recirculation solution and directing the CCh-rich regeneration solution to a regeneration system and directing the CCh-rich recirculation solution to a recirculation system. The outlet system may further comprise a heat exchanger located downstream of the dividing means of the CCh-rich solution outlet system.

[0015] The recirculation system comprises a pump and a means for temperature and flow control of the CCh-rich recirculation solution and further comprising a means for dividing the CCh-rich recirculation solution into portions. In an aspect, the recirculation system comprises a recirculation cooling device for controlling the temperature of the first portion and the second portion of the CCh-rich recirculation solution to about 5°C to about 30°C before introducing the first portion and the second portion of the CCh-rich recirculation solution into the absorber.

[0016] The CCh capture system further comprises a CCh-lean solution feeding system comprising a means for temperature and flow control of the CCh-lean solution. The temperature of the CCh-lean solution can be adjusted to about 5 to about 30 °C before the CCh-lean solution enters the absorber. The CCh-lean solution feeding system comprises a means for dividing the CCh-lean solution into portions. In an aspect, the means for dividing71CCS-510953-WO-2 (BHI0565PCT) is located downstream of the means for temperature control.

[0017] The CO2 capture system can further comprise a regenerator having a single CCh-lean solution outlet for removal of a CCh-depleted solution from the regenerator and in fluid communication with the CCh-lean solution feeding system, wherein the CCh-depleted solution is the CCh-lean solution introduced to the absorber after heat exchange. The CO2- lean solution feeding system may include a heat exchanger located between the regenerator and the absorber. In an aspect, the regenerator comprises a single inlet configured to receive the CCh-rich regeneration solution, particularly a CCh-rich regeneration solution after heat exchange.

[0018] In an aspect, the absorber comprises a first absorption stage that receives a first portion of the CCh-lean solution or CCh-rich recirculation solution, wherein the first absorption stage is located closest to the absorber gas inlet; a second absorption stage that receives a second portion of the CCh-lean solution; a third absorption stage that receives a second portion of the CCh-rich recirculation solution; and wherein the first absorption stage, the second absorption stage, and the third absorption stage are arranged sequentially in the absorber in a direction from the gas inlet to the gas outlet.

[0019] In another aspect, the absorber comprises a first absorption stage that receives a first portion of the CCh-lean solution, wherein the first absorption stage is located closest to the absorber gas inlet, a second absorption stage that receives a first portion of the CCh-rich recirculation solution, a third absorption stage that receives a second portion of the CCh-lean solution, and a fourth absorption stage that receives a second portion of the CCh-rich recirculation solution, and wherein the first absorption stage, the second absorption stage, the third absorption stage, and the fourth absorption stage are arranged sequentially in the absorber in a direction from the gas inlet to the gas outlet.

[0020] The CO2 capture system may further comprise a condensation device configured to cool a treated gas stream removed from the absorber, generating a condensate comprising ammonia and a cooled gas stream; and optionally wherein the absorber further comprises an inlet to receive the condensate.

[0021] In an aspect, the CO2 capture system comprises or consists of a single absorber and a single regenerator, wherein the absorber has a single CC -rich solution outlet configured for removal of a CCh-rich solution from the absorber and the regenerator has a single CCh-lean solution outlet for removal of a CCh-depleted solution from the regenerator.

[0022] A mixed salt process of removing CO2 from a CCh-conlaining gas stream comprises use of a CO2 capture system described herein.71CCS-510953-WO-2 (BHI0565PCT)

[0023] In an aspect, a mixed salt process for removing CO2 from a CCh-containing gas stream comprises introducing a CCh-containing gas stream into an absorber, the absorber having a plurality of absorption stages, and configured to receive a first portion of a CCh-lean solution and a second portion of the CCh-lean solution at different absorption stages; contacting the CCh-containing gas stream with the first portion of the CCh-lean solution and the second portion of the CCh-lean solution; generating a treated gas stream and a CCh-rich solution; dividing the CCh-rich solution into a CCh-rich regeneration solution and a CCh-rich recirculation solution; recirculating a first portion of the CCh-rich recirculation solution and a second portion of the CCh-rich recirculation solution to different absorption stages; and passing the CCh-rich regeneration solution after heat exchange to a regenerator, the regenerator producing a CO2 gas and a CCh-depleted solution as the CCh-lean solution introduced to the absorber after heat exchange. In an aspect, the process uses an absorber having a single CCh-rich solution outlet configured for removal of the CCh-rich solution from the absorber, and a regenerator having a single CC -lean solution outlet for removal of the CCh-depleted solution from the regenerator.

[0024] The absorber of the process comprises a first absorption stage; a second absorption stage; a third absorption stage; and a fourth absorption stage, and the CCh- containing gas stream contacts the first portion of the CCh-lean solution in the first absorption stage, contacts the first portion of the recirculated CCh-rich solution in the second absorption stage, contacts the second portion of the CC -lean solution in the third absorption stage, and contacts the second portion of the recirculated CCh-rich solution in the fourth absorption stage, while the CCh-containing gas stream flows upwards in the absorber.

[0025] The process may further comprise cooling the CCh-rich recirculation solution to a temperature of about 5 °C to about 30°C before introducing the first portion and the second portion of the CCh-rich recirculation solution to the absorber.

[0026] The process may further comprise cooling the treated gas in a condensation device to generate a condensate comprising ammonia and a cooled gas, and optionally recirculating the condensate into the absorber.

[0027] The process and system according to the disclosure are described herein by way of exemplification and not limitation with reference to the Figures.

[0028] Referring to FIGS. 1-3, an absorber (100) is provided. The absorber (100) is configured to receive a CCh-containing gas stream (10) via an inlet (15) located near the bottom of the absorber (100) and to allow the CCh-containing gas stream (10) to flow upward and through the absorber (100) to exit via an outlet (45) located near the top of the absorber71CCS-510953-WO-2 (BHI0565PCT)(100) as a treated gas stream (40). As used herein, “downstream” and “upstream” are determined based on the flow direction the CC -containing gas.

[0029] The CCh-containing gas stream (10) entering the absorber (100) can include air, natural gas, industrial effluents and commercial emissions. In an aspect, the CO2- containing gas stream is a flue gas, which can be the gas produced when fossil fuels such as coal, oil, natural gas, or wood are burned for heat or power. Optionally, the CO2-containing gas stream (10) (e.g. flue gas) is cleaned in a pollution control system (50) before it is introduced into the absorber (100) to remove pollutants such as dust / particulate matter (PM), sulfur oxides, nitrogen oxides, and hydrogen chloride. The pollution control system (50) is known and can include dust collectors and wet or dry scrubbers.

[0030] The absorber (100) has a plurality of absorption stages. As an example, the absorber (100) can include a first absorption stage (105), a second absorption stage (205), a third absorption stage (305), and a fourth absorption stage (405). When the absorber is a column, the first, second, third, and fourth absorption stages (105, 205, 305, and 405) can be positioned sequentially in a direction from the gas inlet (15) to the gas outlet (45), e.g., from the bottom of the absorber to the top of the absorber. There can be one or more additional absorption stages below the first absorption stage, above the fourth absorption stage, between the first and second absorption stages, between the second and the third absorption stages, between the third and fourth absorption stages, or a combination thereof.

[0031] Each absorption stage can include at least one gas-liquid contacting device, where an ammoniated aqueous solution contacts the CCh-containing gas stream (10) as the gas flows upwards through the absorber (100) and the ammoniated solution travels downwards through the absorber (100). Gas-liquid contacting devices can include, for example, structured or random packing materials.

[0032] If needed, the absorption stages can also include liquid distributors (101, 201, 301, 401) located at the top of the respective absorption stages (105, 205, 305, 405). These liquid distributors can be configured to distribute ammoniated aqueous solutions into the corresponding gas-liquid contracting devices (102, 202, 302, 402). The liquid distributors may be configured as, for example, spray head nozzles, conduits with perforations, and / or slots, or a combination thereof.

[0033] As used herein, an ammoniated aqueous solution contains ammonium ions and water. Optionally the ammoniated aqueous solution also contains at least one of bicarbonate ions, carbonate ions, carbamate ions, potassium ions, or dissolved alkanolamines (such as methyldiethanolamine) .71CCS-510953-WO-2 (BHI0565PCT)

[0034] In the process and system described herein, the ammoniated aqueous solution can include the CCh-lean solution (20) and the CCh-rich recirculation solution (32). The absorber (100) is configured to absorb CO? in the CCh-containing gas stream (10), using at least two portions (25, 28) of the same CCh-lean solution (20) entered the absorber (100) at different locations or absorption stages as well as at least two portions (37, 38) of the same CCh-rich recirculation solution (32) entered the absorber (100) at different locations or absorption stages. The CCh-lean solution (20) and the CCh-rich recirculation solution (32) in the absorber contact the CCh-containing gas stream and flow downward, generating a CO2- rich solution (30) near the bottom of the absorber (100).

[0035] The CCh-lean solution (20) can be a CCh-depleted solution (61) generated from a regenerator (60). Preferably, the regenerator (60) has a single outlet (62) for removal of the CCh-depleted solution (61) from the regenerator (60). The CCh-depleted solution (61) then enters a heat exchanger (63) to transfer heat to a CCh-rich regeneration solution (33). After heat exchange, the CCh-depleted solution becomes a CC -lean solution (20). The temperature of the CCh-lean solution (20) can be monitored and further adjusted if needed with a temperature monitoring or controlling device (67). Further temperature adjustment may be achieved by use of a heat exchanger or a cooling device (not shown) located between the heat exchanger (63) and the absorber (100). The inlet temperature of the CCh-lean solution generally is below 35 °C and can be adjusted to about 5 to about 30 °C, preferably about 10 to about 25 °C, and more preferably about 20 °C before the CCh-lean solution enters the absorber.

[0036] To improve the process and system efficiency, the CCh-lean solution (20) is divided into at least two portions (25, 28) with a CCh-lean solution flow control device (22). The locations where a first portion (25) and a second portion (28) of the CCh-lean solution (20) are introduced to the absorber (100) can determine the performance of the absorber (100). As shown in FIGS. 1-3, the first portion (25) of the CCh-lean solution (20) is introduced at an upstream location as compared to where the second portion (28) of the CCh- lean solution (20) is introduced into the absorber.

[0037] The magnitude of the split of the CCh-lean solution can be determined based on the CO2 content in the CCh-containing gas stream (also referred to as “CO2 feed stream” or “feed stream”). In general, a lower CO2 concentration in the feed stream means a less amount of the second portion of the CCh-lean solution. In an aspect, the second portion of the CCh-lean solution and the first portion of the CCh-lean solution can have a ratio of about 4:6 to about 9:1, preferably about 1:1 to about 7:3.71CCS-510953-WO-2 (BHI0565PCT)

[0038] Injecting an adequate amount of lean flow can minimize ammonia leakage.

[0039] In the process and system disclosed herein, a recirculation of a CC -rich solution (30) is implemented in order to increase the contact time between the CO2- containing gas and the lean stream, decrease the absorber mean temperature, and increase the CO2 loading of the solvent in the absorber.

[0040] The absorber (100) can have a single CCh-rich solution outlet (115) configured for removal of the CCh-rich solution (30) from the absorber (100). The CCh-rich solution (30) removed from the absorber can be divided into a CCh-rich regeneration solution (33) and a CCh-rich recirculation solution (32) via a flow control device (31). Up to 50% of the CCh-rich solution (30) can be recirculated to the absorber. In other words, the CCh-rich recirculation solution (32) and the CCh-rich regeneration solution (33) can have a ratio of about 1:9 to about 1: 1, preferably about 7:3 to about 1:1.

[0041] The CCh-rich regeneration solution (33) can be transported to a heat exchanger (63) where it receives heat from a CCh-depleted solution (61) generated from a regenerator (60) via a CCh-rich solution pipe (98). Pumps (66) can be used to facilitate transportation. The heat exchanged CCh-rich regeneration solution (33) is then forwarded to the regenerator (60), where under an elevated temperature, it decomposes, generating a CO2- depleted solution (61) and a CO2 gas (68). The regenerator can operate at a pressure of about 1 bar to about 40 bars and a temperature range of about 80°C to about 180°C. Good performances can be obtained when the regenerator operates at a pressure of about 5 bars to about 20 bars range and a temperature of about 110 °C to about 140°C.

[0042] The CO2 rich recirculation solution (32) can be divided into at least two portions (37, 38) with a recirculation solution flow control device (36), then introduced at two or more locations into the absorber, i.e., two or more different heights. The entry points can determine the performance of the absorber. As shown in FIGS. 1-3, the first portion (37) of the recirculation solution is introduced at an upstream location as compared to where the second portion (38) of the recirculation solution is introduced. The first portion (37) and the second portion (38) of the CO2-rich recirculation solution can be delivered to the absorber via a first recirculation path (90) or a second recirculation path (95) respectively. Pumps (34) can be used for the recirculation and also for recirculation flow control.

[0043] The magnitude of the split between the first portion and the second portions of the CO2-rich solution can be based on the CO2 content in the CO2-containing gas stream. In general, the higher the CO2 concentration in the feed stream, the higher the amount of the recirculated stream on the top of the absorber. The first and second portions of the CO2-rich71CCS-510953-WO-2 (BHI0565PCT) recirculation solution can have a ratio of about 1:9 to about 6:4, preferably about 3:7 to about 1:1.

[0044] The flow rate of the first portion and the second portion of the CCh-rich recirculation solution can be controlled to provide high ammonia capture and leakage containment performance.

[0045] The temperature of the CCh-rich recirculation solution can be monitored and adjusted if needed to a temperature of about 5°C to about 30°C, preferably about 15°C to about 25°C with a recirculation cooling device (35).

[0046] As an example, referring to FIG. 2, the first portion (25) and the second portion (28) of the CCh-lean solution (20) can be introduced into the first absorption stage (105) and the third absorption stage (305) respectively. The first portion (37) and the second portion (38) of the CC -rich recirculation solution (30) can be introduced into the second absorption stage (205) and the fourth absorption stage (405) respectively. While the CO2- containing gas stream (10) flows upwards and through the absorber (100), the CO2- containing gas stream contacts the first portion of the CC -lean solution in the first absorption stage, contacts the first portion of the recirculated CC -rich solution in the second absorption stage, contacts the second portion of the CCh-lean solution in the third absorption stage, and contacts the second portion of the recirculated CCh-rich solution in the fourth absorption stage, generating a treated gas stream (40) at the top of the absorber (100). The treated gas stream (40) has a lower concentration of CO2 as compared to the CCh-containing gas stream (10).

[0047] The treated or cleaned gas stream (40), having a low concentration of carbon dioxide, from the absorber (100) can be forwarded to a condensation device (70), which is optional and which is operative for capturing ammonia from the CCh-containing gas stream that has been treated in the absorber (100). The higher the ammonia leakage from the top outlet of the absorber, the more beneficial the presence of the condensation device. In the condensation device (70), the treated gas stream (40) is cooled, generating a condensate (71) containing ammonia and a cooled treated gas (72). The operative temperature of the condensation device can be as low as about 0 to about 10°C. Optionally, the condensate (71) which includes captured ammonia is transported to the absorber (100) via an ammonia delivery path (75).

[0048] The cooled gas stream (72) can be forwarded to a water wash vessel (80), which is optional and which is operative for capturing additional ammonia from the CO2- containing stream that has been treated in the CO2-absorber and cooled in the condensation71CCS-510953-WO-2 (BHI0565PCT) device. In the water wash vessel (80), the cooled treated gas stream (72) is washed with water (83), generating a cleaned gas stream (81) and an aqueous solution (84) which may contain ammonia.Examples

[0049] A parametric analysis has been made on the CCh-rich solution recirculation fraction. A recirculation is introduced to recirculate a fraction of CCh-rich solution in the absorber. The tests have been conducted with a value of L / G (liquid / gas ratio) equals to 4.26 and a CCh-lean solution of NIH3m=4, K2CO3=2, and CO2 load =0.25. The CCR trends present a maximum around 50% recirculation, as can be seen in FIG. 4A. Without wishing to be bound by theory, it is believed that the recirculated solution cools down the absorber, fostering absorption reactions (exothermal) and increasing the solvent residence time in the absorber. However, for split fractions higher than 0.5, the excessive dilution of the CO2-lean solution causes a drop in CCR. The ammonia slip, instead, decreases with the increase of the recirculation fraction: due to the cooling effect of the recirculation, the partial vapor pressure of NH3 drops as the absorber gets colder.

[0050] A parametric analysis has also been made on the temperature of the recirculated stream at the outlet of the cooling device, with a fixed recirculation fraction of 50%. The results are summarized in FIG. 4B. The data shows that at lower recirculation inlet temperatures, both the CCR and the NH3 slip values reach optimal levels.

[0051] For the following analyses, the recirculation fraction is set to 50% and the recirculation temperature to 20°C. The absorber section is tested by varying the inlet position of the recirculation and lean stream, and the results are summarized in FIG. 5. As shown in FIG. 5, CCR reaches better values when the lean stream is inserted above the recirculation since the lean exploits all the absorption stages. The NH3 slip is minimized when the recirculated stream is inserted above the lean stream. It is believed that the ammonia slip decreases since the gas phase containing NH3 generated at the introduction of the lean flow is absorbed by the CO2-rich solution that is fed to the upper stage; and / or the temperature difference between the lean stream and the recirculated stream promotes the absorption of the ammonia from the gas phase. The CCR decreases because a part of ammonia is bound with the CO2 due to the top-feeding recirculation; the lean goes down for one stage less than those of the entire absorber, and the ammonia results diluted in a solution with a high content of CO2. Since the ammonia slip is a crucial parameter for this carbon capture process, it is preferred that the recirculation inserted is above the lean stream, which can minimize the71CCS-510953-WO-2 (BHI0565PCT) ammonia slip phenomena. The decreased CCR can be compensated by increasing the lean mass flow rate.

[0052] As used herein, “combination” is inclusive of blends, mixtures, alloys, reaction products, and the like. The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. “Or” means “and / or.”

[0053] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” can include a range of ± 8% of a given value.

[0054] Further, it should be noted that the terms “first,” “second,” and the like herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another.

[0055] While typical embodiments have been set forth for the purpose of illustration, the foregoing descriptions should not be deemed to be a limitation on the scope herein. Accordingly, various modifications, adaptations, and alternatives can occur to one skilled in the art without departing from the spirit and scope herein.

Claims

71CCS-510953-WO-2 (BHI0565PCT)CLAIMS1. A mixed salt process CO2 capture system characterized by: an absorber (100) configured to treat a CCh-con tabling gas steam (10) with two or more mixtures of different solvents made from a CCh-lean solution (20) and a CCh-rich recirculation solution (32), the absorber (100) having a gas inlet (15) for introducing the CO2- containing gas stream into the absorber (100); a gas outlet (45) for removing a treated gas stream from the absorber (100); a plurality of absorption stages; and a single CCh-rich solution (30) outlet configured for removal of a CCh-rich solution (30) from the absorber (100), the absorber (100) being configured to receive a first portion of a CCh-lean solution (20) and a second portion of the CC -lean solution (20) at different absorption stages, and configured to receive a first portion of a CCh-rich recirculation solution (32) and a second portion of a CCh-rich recirculation solution (32) at different absorption stages; the CCh-rich solution outlet (105) is in fluid communication with a CCh-rich solution outlet (105) system characterized by a means for dividing the CCh-rich solution (30) removed from the absorber (100) into a CCh-rich regeneration solution (33) and a CCh-rich recirculation solution (32) and directing the CCh-rich regeneration solution (33) to a regeneration system and directing the CCh-rich recirculation solution (32) to a recirculation system; the recirculation system characterized by a pump (34) and a means for temperature and flow control of the CCh-rich recirculation solution (32) and further characterizd by a means for dividing the CCh-rich recirculation solution (32); and a CCh-lean solution (20) feeding system characterized by a means for temperature and flow control of the CCh-lean solution (20).

2. The CO2 capture system of claim 1 , further comprising a regenerator (60) having a single CCh-lean solution (20) outlet for removal of a CCh-depleted solution from the regenerator (61) and in fluid communication with the CCh-lean solution (20) feeding system, wherein the CCh-depleted solution (61) is the CCh-lean solution (20) introduced to the absorber (100) after heat exchange; and optionally the regenerator (60) comprises a single inlet (15) configured to receive the CCh-rich regeneration solution (33).

3. The CO2 capture system of claim 1, wherein the absorber (100) comprises a first absorption stage (105) that receives the first portion of the CCh-lean solution (20) or CCh-rich recirculation solution (32), wherein the first absorption stage (105) is located closest to the absorber (100) gas inlet (15),71CCS-510953-WO-2 (BHI0565PCT) a second absorption stage (205) that receives the second portion of the CCh-lean solution (20), a third absorption stage (305) that receives the second portion of the CCh-rich recirculation solution (32); and wherein the first absorption stage (105), the second absorption stage (205), and the third absorption stage (305) are arranged sequentially in the absorber (100) in a direction from the gas inlet (15) to the gas outlet (45).

4. The CO2 capture system of claim 1, wherein the absorber (100) comprises a first absorption stage (105) that receives the first portion of the CCh-lean solution (20), wherein the first absorption stage (105) is located closest to the absorber (100) gas inlet (15), a second absorption stage (205) that receives the first portion of the CCh-rich recirculation solution (32), a third absorption stage (305) that receives the second portion of the CCh-lean solution (20), and a fourth absorption stage (405) that receives the second portion of the CCh-rich recirculation solution (32), and wherein the first absorption stage (105), the second absorption stage (205), the third absorption stage (305), and the fourth absorption stage (405) are arranged sequentially in the absorber (100) in a direction from the gas inlet (15) to the gas outlet (45).

5. The CO2 capture system of claim 1, wherein the CC -lean solution (20) feeding system comprises a means for dividing the CCh-lean solution (20) into the first portion of a CCh-lean solution (20) and the second portion of the CCh-lean solution (20) with a ratio of about 6:4 to about 1:9, wherein the means for dividing is located after the means for temperature control.

6. The CO2 capture system of claim 1 , wherein the CCh-rich recirculation solution (32) and the CCh-rich regeneration solution (33) have a ratio of about 1:9 to about 1:1.

7. The CO2 capture system of claim 1, wherein the first portion of the CCh-rich recirculation solution (32) and the second portion of the CCh-rich recirculation solution (32) have a ratio of about 1:9 to about 6:4.

8. The CO2 capture system of claim 1, wherein the recirculation system comprises a recirculation cooling device (35) for controlling a temperature of the first portion and the second portion of the CCh-rich recirculation solution (32) to about 5°C to about 30°C71CCS-510953-WO-2 (BHI0565PCT) before introducing the first portion and the second portion of the CCh-rich recirculation solution (32) into the absorber (100).

9. The CO2 capture system of claim 1, further comprising a condensation device (70) configured to cool the treated gas stream removed from the absorber (100), generating a condensate (71) comprising ammonia and a cooled gas stream; and optionally wherein the absorber (100) comprises an inlet to receive the condensate (71).

10. A mixed salt process of removing CO2 from a CCh-containing gas stream (10), the process characterized by: introducing a CCh-containing gas stream (10) into an absorber (100), the absorber (100) having a plurality of absorption stages, and configured to receive a first portion of a CCh-lean solution (20) and a second portion of the CCh-lean solution (20) at different absorption stages, contacting the CCh-containing gas stream (10) with the first portion of the CCh-lean solution (20) and the second portion of the CCh-lean solution (20), generating a treated gas stream and a CCh-rich solution (30), dividing the CCh-rich solution (30) into a CCh-rich regeneration (30) solution and a CCh-rich recirculation solution (32), recirculating a first portion of the CCh-rich recirculation solution (32) and a second portion of the CCh-rich recirculation solution (32) to different absorption stages, and passing the CCh-rich regeneration (30) solution after heat exchange to a regenerator (60), the regenerator (60) producing a CO2 gas (68) and a CCh-depleted solution (61) as the CCh-lean solution (20) introduced to the absorber (100) after heat exchange.

11. The process of claim 10, wherein the absorber (100) has a single CCh-rich solution outlet (105) configured for removal of the CCh-rich solution (30) from the absorber (100), and the regenerator (60) has a single CCh-lean solution outlet (62) for removal of the CCh-depleted solution from the regenerator (61).

12. The process of claim 10, wherein the absorber (100) comprises a first absorption stage (105); a second absorption stage (205); a third absorption stage (305); and a fourth absorption stage (405), and the CCh-containing gas stream (10) contacts the first portion of the CCh-lean solution (20) in the first absorption stage (105), contacts the first portion of the recirculated CCh-rich solution (32) in the second absorption stage (205), contacts the second portion of the CCh-lean solution (20) in the third absorption stage (305), and contacts the second portion of the recirculated CCh-rich solution (32) in the fourth71CCS-510953-WO-2 (BHI0565PCT) absorption stage (405), while the CC -containing gas stream (10) flows upwards in the absorber (100).

13. The process of claim 10, wherein the first portion and the second portion of the CCh-lean solution (20) have a ratio of about 6:4 to about 1:9; the CCh-rich recirculation solution (32) and the CCh-rich regeneration solution (33) have a ratio of about 1:9 to about 1:1; and the first portion of the CCh-rich recirculation solution (32) and the second portion of the CCh-rich recirculation solution (32) have a ratio of about 1:9 to about 6:4.

14. The process of claim 10, further comprising cooling the CCh-rich recirculation solution (32) to a temperature of about 5°C to about 30°C before introducing the first portion and the second portion of the CCh-rich recirculation solution (32) to the absorber (100).

15. The process of claim 10, further comprising cooling the treated gas (40) in a condensation device (70) to generate a condensate (71) comprising ammonia and a cooled gas, and recirculating the condensate (71) into the absorber (100).

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