Carbon capture for gas turbine

Abstract

The present invention relates to a method for capturing CO2 from a CO2-rich gas, a lean exhaust gas is reheated in a heat exchanger and expanded on an expander to provide power to drive a compressor, and a portion of the heat from the cooling of the CO2-rich gas entering the heat exchanger is used to generate steam for regenerating a rich absorbent, wherein the CO2-rich gas is received at near atmospheric pressure and a temperature of 350 DEG C to 900 DEG C, and wherein the incoming exhaust gas is cooled in an exhaust gas heat exchanger and compressed in a compressor before being introduced into the absorber.

Description

Technical Field

[0001] The present invention relates to a method for 2 CO2 is captured from waste gases (e.g. from industrial processes or the combustion of carbonaceous fuels) 2 methods and apparatus. Background Art

[0002] In recent decades, environmental awareness has grown, particularly around the impact of emissions of “greenhouse gases” (i.e. gases that cause the atmosphere to warm). This increased awareness has led to the creation of the United Nations Sustainable Development Goals, which have been adopted by many countries and set specific targets, such as reducing CO 2 greenhouse gas emissions in order to significantly reduce CO 2 However, the world is still highly dependent on fossil fuels, and the transition to other energy sources will take longer than developing and building emission-free or low-emission energy sources.

[0003] Therefore, reducing CO 2 An important strategy for emissions is CO 2 Capture and storage, i.e. from larger or smaller CO 2 Capturing CO from emitting activities 2 and store it in stable geological structures.

[0004] Many CO 2 concepts and projects were captured, but due to the high investment and running costs of these facilities, as well as the lack of political support, few of them progressed from ideas or drawings to actual projects.

[0005] Most of the proposed CO 2 Capture projects are based on post-combustion CO 2 Capture, which contains CO 2 The exhaust gas is introduced into the absorber, containing CO 2 Gas and CO 2 The absorbent is in close contact to remove or at least significantly reduce the CO in the exhaust gas before it is released into the surrounding environment 2 Then the absorbed CO 2 The absorbent is introduced into the regenerator to regenerate the absorbent for reuse, while the captured CO 2 It is then taken out for deposition / storage.

[0006] The most commonly used absorbents are inorganic absorbents (usually aqueous solutions of potassium carbonate) and organic absorbents (usually aqueous solutions of one or more organic amines or amino acids). Organic absorbents tend to degrade during use, especially in the presence of oxygen. Some of the amine degradation products produced during the operation of these devices are known to be toxic and carcinogenic compounds that may react with CO 2 The exhaust gases are released into the surrounding environment together. Operation of capture plants at pressures higher than atmospheric pressure using organic absorbents exacerbates the degradation problem, as compression increases the partial pressure of oxygen. Potassium carbonate, on the other hand, is relatively cheap, chemically stable under the operating conditions of the capture plant, and does not produce toxic or carcinogenic degradation products.

[0007] Capturing CO in capture devices 2 The reaction rate and system balance depend largely on the CO 2 The partial pressure of CO in the capture device 2 The part of the gas that is in close contact with the absorbent. In addition, the use of high pressure can reduce the gas volume and can significantly reduce the size of the equipment, thereby reducing construction costs.

[0008] Norsk Hydro's patent WO 0048709 relates to a method for capturing CO from the exhaust gas of a primary power plant (e.g. a gas turbine based power plant). 2 The expanded and cooled exhaust gas from the gas turbine power plant is recompressed to a pressure of 5 to 30 bar, typically 7 to 20 bar, and the compressed gas is introduced into an absorber and reacted with CO 2 The amine absorbent in the capture device absorber is cooled before contacting the incoming flue gas which will be depleted of CO 2 The exhaust gas is reheated and then expanded by an expander to provide power for the compression of the incoming exhaust gas. The disadvantage of this method is that it requires integration between the gas turbines of the main power generation equipment to operate the auxiliary power generation system, which limits the potential use of the method and equipment in gas turbine equipment. In addition, the method requires integration with a heat recovery steam generator (HRSG) or a gas turbine equipment. Another disadvantage of the method described herein is the use of an amine aqueous solution as the absorbent. At the temperature in the absorber, CO 2 The amines used in the absorbent are easily degraded by the oxygen present in the exhaust gases, which are in close contact with the absorbent in the absorber. The degree of degradation depends both on the amine in question, the temperature and also on the oxygen partial pressure. Some of the amines used or their degradation products are known or suspected to be toxic or even carcinogenic.

[0009] Another absorbent is aqueous potassium carbonate solution. 2Absorbents have been known for decades, see for example US 7.328.581, EP 2300129 and EP 2643559, originally filed by Sargas AS and now assigned to CO 2 Capso Corporation 2 Capsol), EP 3359281 to Capsol Eop AS, and the citations cited therein.

[0010] The present invention aims to improve the CO 2 Capture, thus allowing CO2 from any source to be 2 Capturing CO from gases 2 without the need to 2 The gas source is formed integrally. Summary of the invention

[0011] According to a first aspect, the present invention relates to a method for producing a 2 Capturing CO from gases 2 method,

[0012] From the rich CO 2 Absorbing CO in gas 2 To produce lean CO 2 Gas and CO-rich 2 absorbent, where the rich CO is extracted 2 The absorbent is introduced into a regenerator where it is stripped to produce a regenerated absorbent or lean absorbent which is recycled to the absorber, CO 2 is further processed, wherein the lean exhaust gas is reheated in a heat exchanger and expanded on an expander to provide power to drive the compressor, and wherein the rich CO entering from the heat exchanger is 2 A portion of the heat from the cooling of the gas is used to generate steam to regenerate the rich absorbent, wherein the rich CO 2 The gas is received at near atmospheric pressure and a temperature of 350°C to 900°C, wherein the incoming exhaust gas is cooled in an exhaust gas heat exchanger and compressed in a compressor before being introduced into the absorber.

[0013] The incoming exhaust gas temperature corresponds to the typical temperatures of a simple-cycle gas turbine power plant. At a temperature of the incoming exhaust gas of about 350°C, the energy used by the expander to expand the lean exhaust gas corresponds to the energy required to compress the incoming exhaust in the exhaust gas compressor. At higher temperatures, the energy produced by the expansion exceeds the energy used for compression, so that the excess energy can be used to generate electricity by means of an electromechanical generator in order to provide electricity to different consumers in the plant or for export. However, there is a practical upper temperature limit in order to avoid the use of extremely expensive materials as heat exchangers, the cost of which would make the plant prohibitively expensive.

[0014] In an embodiment, before entering the heat exchanger 2, the temperature of the incoming exhaust gas may be increased by duct combustion 70, and the lean exhaust gas may be heated by the incoming exhaust gas.

[0015] In an embodiment, the lean exhaust gas expanded on the expander 9 enters the heat exchanger 71. In an embodiment, the lean exhaust gas heats the incoming exhaust gas in the heat exchanger 71.

[0016] According to a second aspect, the invention relates to a method for extracting a CO-rich 2 Capturing CO from gases 2 equipment,

[0017] The apparatus comprises an inlet exhaust gas pipe (1) for receiving incoming exhaust gas, one or more exhaust gas heat exchangers (2, 2', 2", 2'") for cooling the incoming exhaust gas, one or more compressors (5, 5', 5") for compressing the cooled exhaust gas, and one or more exhaust gas heat exchangers (2, 2', 2", 2'") for absorbing CO in the incoming exhaust gas using an aqueous potassium carbonate absorbent. 2an absorber (20) of the present invention, a lean exhaust gas pipe (26) for introducing lean exhaust gas into an exhaust gas heat exchanger (2, 2', 2", 2'") to heat the lean exhaust gas with the incoming exhaust gas, an expander (9) for expanding the lean exhaust gas before releasing the lean exhaust gas into the atmosphere, wherein the expander (9) is arranged to drive the compressor (5, 5', 5"), a rich absorbent pipe (23) for withdrawing the rich absorbent from the absorbent and introducing the rich absorbent into a regenerator (27) to regenerate the absorbent to produce a lean absorbent, a lean absorbent pipe (22) for returning the regenerated or lean absorbent to the absorber (20), wherein a steam generator (12) is provided through a steam pipe (1 2') and a cooling water return pipe (12") are connected to an exhaust gas heat exchanger (2") or one of the heat coils (65) to generate steam, and wherein a reboiler steam pipe (13) is arranged to convey the generated steam to a reboiler (15) to heat the lean absorbent to generate steam for regenerating the absorbent in a regenerator (27), and a condensate return pipe (14) for returning water condensed during heating of the lean absorbent in the reboiler (15) to the steam generator (12), characterized in that the heat exchanger (2, 2', 2", 2'") for cooling the incoming exhaust gas is arranged upstream of one or more compressors (5, 5', 5") for compressing the cooled exhaust gas.

[0018] BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of a first embodiment of the device according to the invention, and

[0020] Figure 2 is a schematic diagram of a second embodiment according to the present invention.

[0021] Figure 3 is a schematic diagram of another embodiment (70, 71) according to the present invention.

[0022] Reference numerals

[0023] 1. Exhaust pipe

[0024] 2. Exhaust gas heat exchanger, 2, 2', 2", 2"'

[0025] 3. Cooling exhaust pipe

[0026] 4. Exhaust gas cooler

[0027] 5. Compressor 5, 5', 5"

[0028] 6. Intercooler 6, 6'

[0029] 7. Common axis

[0030] 8. Motor / Expander

[0031] 9. Lean exhaust gas expander

[0032] 10. Cooling lean exhaust gas pipe

[0033] 11. External exhaust pipe

[0034] 12. Steam generator, 12' steam pipe, 12' cooling water return pipe

[0035] 13. Reboiler steam pipe

[0036] 14. Condensate return pipe

[0037] 15. Reboiler

[0038] 16. Condensate return pump

[0039] 17.Compressed exhaust pipe 18. 19.

[0042] 20. Absorber 21. Absorber filler 21, 21', 21"

[0043] 22. Lean absorbent tube

[0044] 23. Rich absorbent tube

[0045] 24. Rich absorbent pump

[0046] 25. Rich flash tank

[0047] 26. Lean exhaust pipe

[0048] 27. Regenerator 28. Regenerator packing, 28, 28', 28"

[0049] 29. Recycle the collector plate

[0050] 30. Recycling Cooler

[0051] 31.CO 2 Cooler collector plate

[0052] 32.CO 2 Cooler

[0053] 33.CO 2 Extraction tube

[0054] 34.CO 2 Cooling and compression equipment 35. Lean absorbent pipe

[0055] 36.Reboiler tube

[0056] 37. Reboiler steam pipe

[0057] 38. Lean absorbent flash tank

[0058] 39. Lean absorbent flash steam pipe

[0059] 40. Lean flash steam compressor

[0060] 41. Lean flash liquid extraction pipe

[0061] 42.Absorbent supply system 43.CO 2 Cooler Pump, 43'CO 2 Cooler pipe 44.CO 2 Cooling water cooler

[0062] 45.CO 2 Cooler water pipe

[0063] 46. ​​Heat recovery cooler extraction pipe

[0064] 47.First cooling water flash tank

[0065] 48.First flash steam extraction pipe

[0066] 49.First flash steam compressor

[0067] 50. Flash tube

[0068] 51.First water pipe

[0069] 52. Second cooling water flash tank

[0070] 53. Recycling cooler water pipes

[0071] 54.Recycling cooler water pump

[0072] 55. Second flash steam extraction pipe

[0073] 56. Second flash steam compressor

[0074] 57.Recovery cooler heat exchanger

[0075] 58. Separation tank

[0076] 59. Separate water pipes

[0077] 60.Lean absorbent heat exchanger

[0078] 61.Absorbent filter

[0079] 62.Lean exhaust gas separation tank

[0080] 63. Condenser

[0081] 64.Heat exchange coil

[0082] 65.Heat exchange coil

[0083] 66.Heat exchange coil

[0084] 67.Heat exchanger

[0085] 68.Heat exchange coil

[0086] 69.Heat exchange coil

[0087] 70.Pipeline Burner

[0088] 71.Heat exchanger DETAILED DESCRIPTION

[0089] Figure 1 A first embodiment according to the invention is shown. CO is captured from 2 The CO 2 The gas is usually exhaust gas from a gas turbine, from an industrial process or from a combustion of carbonaceous materials such as coal or a waste incineration plant, and is introduced into the device through an exhaust pipe 1. The exhaust gas temperature in the exhaust pipe is usually around 350° C. to 800° C., for example 500° C. to 600° C., depending on the source of the exhaust gas.

[0090] The flue gas in flue 1 is directed to one or more heat exchangers to cool the incoming flue gas and transfer heat to heat the outgoing or lean flue gas, as further described below, and to generate steam for a reboiler, as described below. Figure 1 The use of three heat exchangers 2', 2", 2"' to cool the incoming exhaust gas is shown, but a person skilled in the art will appreciate that the heat exchangers 2', 2", 2"' can be replaced by one heat exchanger 2, as described below with reference to Figure 2 described.

[0091] Reference again Figure 1 The incoming exhaust gas is first introduced into the first exhaust gas heat exchanger 2', in which the exhaust gas is cooled to a temperature of 250°C to 130°C, for lean CO 2 The exhaust gas, for example, is cooled to a temperature of 180° C. to 150° C., as will be further described below. The exhaust gas leaving the first exhaust gas heat exchanger 2' is then introduced into a reboiler heat exchanger 2" and further cooled therein to produce steam for a reboiler 15, as will be further described below. After leaving the reboiler cooler 2", the exhaust gas is introduced into a second exhaust gas heat exchanger 2"' where the compressed CO 2After cleaning the flue gas, the exhaust gas is further cooled to a temperature of about 100°C to 110°C. The reboiler cooler 2" is supplied with cooling water through a steam pipe 12'. The heated water and steam leave the second exhaust gas heat exchanger 2" through a steam pipe 12" and are introduced into a steam generator 12, where the hot water and steam are separated to produce steam, which is directed to a reboiler 15 through a reboiler steam pipe 13, as will be further described below. The condensed steam from the reboiler is pumped by a condensate return pump 16 and returned to the steam generator 12 through a condensate pipe 14. The water collected by the steam generator 12 is returned to the second exhaust gas heat exchanger through a cooling water pipe 12'.

[0092] The exhaust gas thus cooled is extracted from the second exhaust gas heat exchanger 2'" through the cooled exhaust gas pipe 3 and introduced into a series of compressors 5, 5', 5" for compressing the exhaust gas to a pressure of 6 bara to 20 bara, for example 8 bara to 20 bara, for example 12 bara to 18 bara, or 15 bara to 17 bara. The exhaust gas can be further cooled in the exhaust gas cooler 4 before being introduced into the compressor. In addition, intercoolers 6, 6' are preferably arranged between the compressors 5, 5', 5" for cooling the compressed exhaust gas. The series of compressors 5, 5', 5" are preferably arranged on a common shaft 7 as a lean exhaust gas expander 9 and a motor / generator 8, since the compressors are preferably driven by the lean exhaust gas expander and possibly the motor / generator 8. Those skilled in the art will understand that the number of compressors 5, 5', 5" shown in the figures is given for illustrative purposes and that the actual number of compressors may vary depending on the actual design. The same applies to the intercoolers 6, 6'.

[0093] Then, the exhaust gas compressed by the compressors 5, 5', 5" is introduced into the lower part of the absorber 20 through the compressed exhaust gas pipe 17. In the absorber 20, the exhaust gas flows in a countercurrent manner through the potassium carbonate aqueous solution absorbent on one or more absorber packings 21, 21', 21". The absorbent is introduced into the absorber 20 from the lean absorbent pipe 22, reaches the top of the upper absorber packing 21", flows through the packing under the action of gravity, and is collected at the bottom of the absorber 20. Those skilled in the art will understand that the number of absorber packings 21, 21', 21" shown in the figure is given for illustrative purposes, and the actual number of packings may vary depending on the actual design.

[0094] Absorbs CO 2 The absorbent, or "rich absorbent" as used herein, is collected at the bottom of absorber 20 and is withdrawn from the bottom of absorber 20 through rich absorbent pipe 23, as described below. The exhaust gas leaving the top of upper absorbent packing 21" contains CO 2The lean exhaust gas which has been absorbed, referred to herein as "lean exhaust gas", is withdrawn through the lean exhaust gas pipe 26. The lean exhaust gas in the lean exhaust gas pipe 26 is then heated to a temperature of about 360°C to 790°C against the heat exchangers 2"' and 2' and is withdrawn from the heat exchanger through the reheated lean exhaust gas pipe 10 and introduced into the lean flue gas expander 9 to ambient pressure, thereby providing power for driving the compressors 5, 5', 5". Typically, the power generated in the lean flue gas expander 9 is sufficient to drive the compressor. The additional electricity generated in the flue gas expander can be used to generate electricity in the motor / generator 8. During the start-up of the equipment, the motor / generator 8 is used as an electric motor. The lean exhaust gas leaving the lean exhaust gas expander 9 is then discharged into the atmosphere at the output exhaust gas pipe 11 (typically through a chimney not shown).

[0095] The temperature of the incoming exhaust gases corresponds to the typical temperatures of a simple-cycle gas turbine power plant. In one embodiment, the lean exhaust gases are heated by the incoming exhaust gases, for example, by means of a duct burner 70 before entering the heat exchanger 2. Thus, the increased temperature of the incoming exhaust gases in the heat exchanger 2 provides more energy for the lean exhaust gases. The energy used by the expander to expand the lean exhaust gases corresponds to the energy required to compress the incoming exhaust gases in the exhaust gas compressor. At higher temperatures, the energy produced by expansion exceeds the energy used for compression, so that the excess energy can be used to generate electricity by means of an electromechanical generator in order to provide electricity to different consumers in the plant or for export.

[0096] The heat exchangers 2', 2", 2"' can be combined in one heat exchanger 2, as described below with reference to Figure 2 As described, the heat exchange coils 64, 65, 66 are arranged at different heat levels in the heat exchanger 2 to achieve the required heat transfer.

[0097] The rich absorbent collected at the bottom of the absorber 20 is withdrawn through the rich absorbent pipe 23, pumped through the rich absorbent pump 24 and introduced into the regenerator 27. An optional rich flash tank 25 may be arranged on the rich absorbent pipe 23 to flash oxygen released into the atmosphere or recycled to the compressor inlet before the rich absorbent is introduced into the regenerator 27.

[0098] Regenerator packing 28, 28', 28" is arranged in the regenerator below the position where the rich absorbent is introduced into the regenerator 27. The rich absorbent flows downward through the regenerator packing 28, 28', 28" under the action of gravity, countercurrently with the steam introduced into the regenerator below the regenerator packing, so as to release CO from the rich absorbent. 2 Those skilled in the art will appreciate that the number of regenerator packings 28, 28', 28" shown in the figures is given for illustrative purposes and the actual number of packings may vary depending on the actual design.

[0099] Lean absorbent, i.e. CO released 2The absorbent is collected at the bottom of the regenerator tower, while the released CO 2 and steam flow upward in the regenerator tower 27 and enter the recovery cooler 30 where the CO 2 The flow of steam is cooled by counter-flow with cooling water from the recovery cooler water pipe 53. 2 The flow-heated cooling water is collected at the recovery collector plate 29, and is extracted through the recovery cooler extraction pipe 46, and flashed into the first cooling water flash tank 47 to separate steam from water. The steam in the first cooling water flash tank 47 is extracted through the first flash steam extraction pipe 48, compressed in the first flash steam compressor 49, and introduced as stripping steam into the regenerator 27 through the flash pipe 50, located below the regenerator packing 28, 28', 28". The water phase from the first cooling water flash tank 47 is extracted through the first flash water extraction pipe 51, and flashed into the second cooling water flash tank 52 to separate the water from the steam. The steam in the flash tank 52 is extracted through the second flash steam extraction pipe 55, compressed in the second flash steam compressor 56, and mixed with the flash steam from the first cooling water flash tank 47 in the flash pipe 50. The water collected in the second cooling water flash tank 52 is extracted through the recovery cooler water pipe 53, pumped by the recovery cooling water pump, and introduced into the top of the recovery cooler 30 as described above.

[0100] CO leaving the recovery cooler 2 and steam via CO 2 CO enters the cooler collecting plate 31 2 The cooler 32 further cools the 2 The cooling water introduced into the cooler water pipe 45 is cooled by countercurrent cooling. 2 The cooler is collected at the collecting plate 31 and the CO 2 The cooler recirculation pipe 43' is drawn out and the CO 2 Cooler pump 43 passes CO 2 The cooling water is pumped to the cooler 44 and is passed through the CO 2 Cooler water pipe 45 enters CO 2 Cooler 32. Steam and CO at the top of regenerator 27 2 The gas phase passes through CO 2 Extraction tube 33 is taken out and in CO 2 The product is further processed by drying and compression in cooling and compression equipment 34 to obtain substantially pure CO 2 For safe deposition or storage.

[0101] The lean absorbent or regenerated absorbent is collected at the bottom of the regenerator 27 and withdrawn through the lean absorbent line 35. The lean absorbent is preferably introduced into a lean absorbent flash tank 38 and separated into a vapor phase and a liquid phase. The vapor phase is withdrawn through a lean flash steam line 39, compressed in a lean flash steam compressor 40, and introduced as additional stripping steam into the regenerator 27 below the regenerator packing 28, 28', 28". The liquid phase is withdrawn through a lean flash liquid extraction line 41 and pumped by a lean absorbent pump through a lean absorbent line 22 and introduced into the absorber 20 as described above. An absorbent make-up system 42 is preferably arranged on the lines 41, 22 for removing excess absorbent or adding more absorbent as required.

[0102] As described above, the amount of steam generated by flash evaporation for regeneration of the absorbent in the regenerator 27 is insufficient, and additional steam must be added. A portion of the lean absorbent at the bottom of the regenerator 27 is extracted through the reboiler pipe 36 and introduced into the boiler 15, where the lean absorbent is heated according to the steam introduced from the reboiler steam pipe 13 to generate steam. The steam generated in the reboiler is introduced as stripping steam into the regenerator 27 below the regenerator packing through the reboiler stripper steam pipe 37. The cooling steam from the reboiler steam pipe 13 is extracted through the condenser pipe 14 via the pump 16.

[0103] Figure 2 based on Figure 1 , but including Figure 1 Different features not described in the basic configuration. Those skilled in the art will understand that Figure 1 Additional features shown in the figure that are dependent on each other may be included separately Figure 1 in the basic configuration. Figure 1 and Figure 2 The elements present in the Figure 2 mentioned in the description.

[0104] Figure 2 An embodiment is shown in which the heat exchangers 2', 2", 2'" are replaced by a single multi-stage heat exchanger 2 having heat exchange coils 64, 65, 66 at different heights of the heat exchanger 2. It is well known to those skilled in the art to make such a replacement, in practice a combined heat exchanger is usually shown as a single unit.

[0105] An optional lean exhaust gas line separator 62 may be arranged on the lean exhaust gas line 26 to separate and remove condensed water from the lean exhaust gas through the condenser line 63 before the lean exhaust gas is introduced into the heat exchanger 2 , 2 ′, 2 ″, 2 ′″.

[0106] The lean exhaust gas leaving the lean exhaust gas expander 9 may still be relatively hot. If the temperature of the expanded lean exhaust gas is above 120°C, it may be beneficial to further cool the exhaust gas using cooling water in the lean expanded exhaust gas heat exchanger 67 to produce steam in the reboiler heat exchange coil 69 and / or the recovery heater heat exchange coil 68 before releasing the exhaust gas through the cooled lean exhaust gas pipe 11'. The steam produced in the reboiler steam exchange coil 69 is directed to the reboiler 15 for heating the lean absorbent therein, and the water cooled and condensed thereby is returned to the reboiler heat exchange coil 69 to reduce the demand for steam from the steam generator 12. The steam produced in the recovery cooler heat exchange coil 68 is directed to the recovery cooler heat exchanger 57 to further heat the cooling water from the recovery cooler in the pipe 46, thereby producing more steam in the flash tanks 47, 52.

[0107] Can be in CO 2 CO is arranged in the extraction pipe 33 2 Separator 58, for removing steam and CO 2 Condensate in the flow, thereby reducing the amount of CO 2 The water volume of the device 34. The water collected in the separation tank is pumped out through the separation water pipe 59.

[0108] Figure 2 Another design of the absorber 20 is also shown, as well as the process of absorbent flowing into the absorber. The lean absorbent stream withdrawn from the lean absorbent pipe 35 is divided into two streams, optionally after flashing in the lean absorbent flash tank 38 as described above, and enters the first lean absorbent pipe 22' and the second lean absorbent pipe 22". The lean absorbent in the first lean absorbent pipe 22' is introduced into the absorber 20 at the top of one of the middle packings, for example, at the top of the second absorber packing, i.e., 21' among the three packings 21, 21', 21", and is combined with the CO2-rich stream entering from the packing below. 2 The gas flows in countercurrent. The lean absorbent in the second lean absorbent pipe 22" is heated by the lean absorbent heat exchanger 60 against the compressed rich CO in the compressed exhaust pipe 17. 2 The gas is cooled, the temperature of the compressed exhaust gas pipe is usually about 60°C, and is introduced into the top of the uppermost absorbent packing 21". As described, the lean absorbent is divided into two streams and the cooled lean absorbent is introduced into the top of the uppermost absorbent packing 21", which can increase the CO in the absorber. 2 The total absorption capacity of CO in the gas flowing upward in the absorber 2 The concentration is obtained by absorbing CO in an absorbent flowing countercurrent to the gas. 2 However, absorption is an exothermic process and as the gas moves upward, the temperature increases. Introducing lean and cooled absorbent on top of the uppermost absorbent packing cools the gas and enables the uppermost absorber packing to absorb more efficiently.

[0109] An optional absorbent filter 61 can be arranged to remove particles from the lean absorbent. Those skilled in the art will understand that the optional lean absorbent filter 61 can be arranged at alternative locations in the lean absorbent stream.

[0110] Those skilled in the art will understand that the splitting of the lean absorbent described with reference to Figure 2 can also be applied to Figure 2 the embodiments of

Claims

1. From rich CO 2 Capturing CO from gases 2 method, Among them, CO 2 Absorbing CO in gas 2 To produce lean CO 2 Gas and CO-rich 2 absorbent, where the rich CO is extracted 2 The absorbent is introduced into a regenerator where it is stripped to produce a regenerated absorbent or lean absorbent which is recycled to the absorber, CO 2 is further processed, Wherein, the lean exhaust gas is reheated in the heat exchangers (2, 2', 2", 2''') and expanded in the expander (9) to provide power for driving the compressors (5, 5', 5"), and The CO2-rich gas entering from the heat exchanger (2, 2', 2", 2"') 2 Part of the heat from the cooling of the gas is used to generate steam to regenerate the rich absorbent. characterized in that, The CO-rich 2 The gas is received at near atmospheric pressure and a temperature of 350°C to 900°C, wherein the incoming exhaust gas is cooled in an exhaust gas heat exchanger (2, 2', 2", 2'") and compressed in a compressor (5, 5', 5") before being introduced into the absorber.

2. The method according to claim 1, wherein the temperature of the incoming exhaust gas is increased before entering the heat exchanger 2.

3. The method according to claim 2, wherein the temperature of the incoming exhaust gas is increased by means of a duct burner 70.

4. The method according to the preceding claims, wherein the lean exhaust gas expanded in the expander 9 enters the heat exchanger 71.

5. The method according to claim 4, wherein the lean exhaust gas heats the incoming exhaust gas in the heat exchanger 71.

6. Used to remove the rich CO from the incoming 2 Capturing CO from gases 2 equipment, The apparatus comprises an inlet exhaust gas pipe (1) for receiving incoming exhaust gas, one or more exhaust gas heat exchangers (2, 2', 2", 2'") for cooling the incoming exhaust gas, one or more compressors (5, 5', 5") for compressing the cooled exhaust gas, and one or more exhaust gas heat exchangers (2, 2', 2", 2'") for absorbing CO in the incoming exhaust gas using an aqueous potassium carbonate absorbent. 2 an absorber (20) of the present invention, a lean exhaust gas pipe (26) for introducing lean exhaust gas into an exhaust gas heat exchanger (2, 2', 2", 2'") to heat the lean exhaust gas with the incoming exhaust gas, an expander (9) for expanding the lean exhaust gas before releasing the lean exhaust gas into the atmosphere, wherein the expander (9) is arranged to drive the compressor (5, 5', 5"), a rich absorbent pipe (23) for withdrawing the rich absorbent from the absorbent and introducing the rich absorbent into a regenerator (27) to regenerate the absorbent to produce a lean absorbent, a lean absorbent pipe (22) for returning the regenerated or lean absorbent to the absorber (20), Wherein, the steam generator (12) is connected to one of the exhaust gas heat exchanger (2") or the heat coil (65) through a steam pipe (12') and a cooling water return pipe (12") to generate steam, and wherein the reboiler steam pipe (13) is arranged to convey the generated steam into the reboiler (15) to heat the lean absorbent to generate steam for regenerating the absorbent in the regenerator (27), and a condensate return pipe (14) for returning the water condensed during heating the lean absorbent in the reboiler (15) to the steam generator (12), characterized in that, the heat exchangers (2, 2', 2", 2''') for cooling the incoming exhaust gas are arranged upstream of one or more compressors (5, 5', 5") for compressing the cooled exhaust gas.

7. The device according to claim 6, comprising a heater (70) located upstream of the heat exchanger (2).

8. The device according to claim 7, wherein the heater (70) is a duct burner.

9. The device according to claim 6, comprising a heat exchanger (71) located downstream of the expander (9).

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