Flue gas carbon capture system and method for capturing carbon from flue gas

Abstract

The present invention relates to the field of carbon capture technology, and discloses a flue gas carbon capture system and a method for carbon capture from flue gas. The system includes a carbon capture subsystem and a steam supply subsystem; the carbon capture subsystem includes a lithium bromide absorption refrigerator, a carbon capture absorption tower, a lean-rich liquid heat exchanger, a regeneration tower, a compressor, and a reboiler; the lithium bromide absorption refrigerator is used to cool the flue gas to be treated, and the low-temperature flue gas generated by the lithium bromide absorption refrigerator is carbon captured in the carbon capture absorption tower; the rich liquid generated in the carbon capture absorption tower sequentially enters the lean-rich liquid heat exchanger and the regeneration tower; the lean liquid generated in the regeneration tower exchanges heat with the rich liquid in the lean-rich liquid heat exchanger and then enters the carbon capture absorption tower for reuse; the heating steam from the steam supply subsystem sequentially enters the compressor, the reboiler, and the lithium bromide absorption refrigerator. The system described in the present invention improves coal utilization and carbon capture efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon capture, and in particular to a flue gas carbon capture system and a method for capturing carbon from flue gas. Background Art

[0002] After passing through the wet flue gas desulfurization tower, the temperature is around 50°C. The clean flue gas contains a large amount of moisture and latent heat. If the wet flue gas is directly introduced into the carbon capture process, the high moisture content will affect the water balance in the carbon capture process, disrupting the concentration stability of the carbon capture absorbent, and causing large fluctuations in the subsequent flue gas carbon capture effect. Currently, the mainstream wet smoke plume removal technologies include flue gas condensation, membrane processes, and absorption processes.

[0003] The more common condensation technologies are indirect cooling technology based on condensers and direct cooling technology based on spray cooling. Although indirect cooling technology is mature, flue modification is difficult, and there are scaling and corrosion problems, requiring sufficient induced draft fan margin. Direct cooling technology has low modification and operating costs, but the water balance problem cannot be solved.

[0004] The membrane process uses a fiber membrane to selectively filter and remove water vapor from flue gas. It occupies a small footprint, minimizes energy loss, and is easy to operate. The choice of membrane material is crucial. Currently used membranes in industry generally have poor tolerance to flue gas dust and gypsum scale, leading to scaling and clogging.

[0005] The absorption process uses an absorbent to selectively absorb water vapor for flue gas dehumidification. This process does not require additional heating or cooling during the water capture process, resulting in a high capture rate. However, there are issues such as high energy consumption for absorbent regeneration, equipment corrosion, and safety concerns. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problems existing in the prior art of directly introducing wet flue gas into the carbon capture process system, in which the high moisture content affects the water balance in the carbon capture process, destroys the concentration stability of the carbon capture absorbent, and causes large fluctuations in the subsequent flue gas carbon capture effect. The present invention provides a flue gas carbon capture system and a method for capturing carbon from flue gas.

[0007] In order to achieve the above-mentioned object, the present invention provides a flue gas carbon capture system in one aspect, which includes a carbon capture subsystem and a steam supply subsystem;

[0008] The carbon capture subsystem includes a lithium bromide absorption refrigerator, a carbon capture absorption tower, a lean and rich liquid heat exchanger, a regeneration tower, a compressor and a reboiler;

[0009] The lithium bromide absorption refrigerator is used to cool the flue gas to be treated, and the low-temperature flue gas generated by the lithium bromide absorption refrigerator is used to capture carbon in the carbon capture absorption tower;

[0010] The rich liquid generated in the carbon capture absorption tower enters the lean and rich liquid heat exchanger and the regeneration tower in sequence, and the rich liquid in the regeneration tower circulates into the reboiler for heating and then returns to the regeneration tower;

[0011] The lean liquid generated in the regeneration tower exchanges heat with the rich liquid in the lean-rich liquid heat exchanger, and then enters the carbon capture absorption tower for reuse;

[0012] The regeneration gas generated in the regeneration tower is compressed in the compressor;

[0013] The heating steam from the steam supply subsystem enters the compressor, the reboiler and the lithium bromide absorption refrigerator in sequence.

[0014] Preferably, the system further comprises a regeneration gas cooler, and the regeneration gas generated in the regeneration tower is cooled in the regeneration gas cooler before entering the compressor.

[0015] Preferably, the regeneration gas generated in the regeneration tower passes through the lithium bromide absorption refrigerator before entering the regeneration gas cooler.

[0016] Preferably, the steam supply subsystem includes a desulfurization tower induced draft fan and a heating main pipe.

[0017] Preferably, the system further comprises a lean liquid cooler, and the lean liquid after heat exchange with the rich liquid in the lean-rich liquid heat exchanger first enters the lean liquid cooler for cooling before entering the carbon capture absorption tower.

[0018] Preferably, the system further comprises a carbon capture induced draft fan for conveying the flue gas to be treated to the lithium bromide absorption chiller.

[0019] A second aspect of the present invention provides a method for capturing carbon from flue gas, the method being implemented in a system comprising a carbon capture subsystem and a steam supply subsystem;

[0020] The carbon capture subsystem includes a lithium bromide absorption refrigerator, a carbon capture absorption tower, a lean and rich liquid heat exchanger, a regeneration tower, a compressor and a reboiler;

[0021] The method includes:

[0022] The flue gas to be treated is cooled in the lithium bromide absorption refrigerator, and the generated low-temperature flue gas is carbon captured in the carbon capture absorption tower;

[0023] The rich liquid generated in the carbon capture absorption tower enters the lean and rich liquid heat exchanger and the regeneration tower in sequence, and the rich liquid in the regeneration tower circulates into the reboiler for heating and then returns to the regeneration tower;

[0024] The rich liquid is regenerated in the regeneration tower, and the generated lean liquid exchanges heat with the rich liquid in the lean-rich liquid heat exchanger, and then enters the carbon capture absorption tower for reuse;

[0025] The regeneration gas generated in the regeneration tower is compressed in the compressor;

[0026] The heating steam from the steam supply subsystem enters the compressor, the reboiler and the lithium bromide absorption refrigerator in sequence.

[0027] Preferably, the system further comprises a regeneration gas cooler, and the method further comprises: cooling the regeneration gas from the lithium bromide absorption chiller in the regeneration gas cooler before entering the compressor;

[0028] Preferably, the regeneration gas generated in the regeneration tower passes through the lithium bromide absorption refrigerator before entering the regeneration gas cooler.

[0029] Preferably, the system further comprises a lean liquid cooler, and the method further comprises: the lean liquid after heat exchange with the rich liquid in the lean-rich liquid heat exchanger first enters the lean liquid cooler for cooling before entering the carbon capture absorption tower.

[0030] Preferably, the absorbent in the carbon capture absorption tower is an alcoholamine absorption liquid;

[0031] Preferably, the flue gas to be treated is the flue gas from a coal-fired power plant after being subjected to wet electrostatic precipitator.

[0032] In the present invention, the flue gas to be treated is cooled in a lithium bromide absorption refrigerator, thereby reducing the water content of the flue gas when the saturated wet flue gas enters the carbon capture absorption tower, ensuring the stability of the carbon capture system, and effectively improving the carbon capture efficiency of the coal-fired power plant; at the same time, the lithium bromide absorption refrigerator is used in conjunction with steam waste heat, and the steam output from the reboiler is used as the heat source input to the lithium bromide absorption refrigerator, thereby improving the energy utilization rate of the coal-fired system. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the flue gas carbon capture system provided by the present invention.

[0034] Description of Reference Numerals

[0035] 1-Rich liquid pump; 2-Desulfurization tower induced draft fan; 3-Carbon capture induced draft fan; 4-Lithium bromide absorption chiller; 5-Regeneration gas cooler; 6-Carbon capture absorption tower; 7-Lean liquid pump; 8-Lean liquid cooler; 9-Lean and rich liquid heat exchanger; 10-Regeneration tower; 11-Carbon dioxide compressor; 12-Reboiler; 13-First valve; 14-Second valve; 15-Heating main pipe; 16-Steam turbine; 17-High auxiliary header. DETAILED DESCRIPTION

[0036] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0037] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0038] The existing carbon capture process follows this process: coal-fired power plant flue gas passes through a wet electrostatic precipitator (ESP) and is then directed to a carbon capture system. After scrubbing, cooling, and deep impurity removal within the ESP, the flue gas enters an absorption tower where it undergoes countercurrent contact with a carbon dioxide absorbent to form a rich liquid. This rich liquid is then heated and regenerated in a regeneration tower before being dried, compressed, and liquefied to produce the carbon dioxide product. Because the wet flue gas is not recooled in this process, it contains a high moisture content. This high moisture content continuously dilutes the concentration of the complex amine absorbent in the absorption tower, impacting absorption efficiency and regeneration energy consumption.

[0039] In view of this, the present invention provides a flue gas carbon capture system, which includes a carbon capture subsystem and a steam supply subsystem; please refer to Figure 1 ;

[0040] The carbon capture subsystem includes a lithium bromide absorption refrigerator 4, a carbon capture absorption tower 6, a lean and rich liquid heat exchanger 9, a regeneration tower 10, a compressor 11 and a reboiler 12;

[0041] The lithium bromide absorption refrigerator 4 is used to cool the flue gas to be treated, and the low-temperature flue gas generated by the lithium bromide absorption refrigerator 4 is carbon captured in the carbon capture absorption tower 6;

[0042] The rich liquid generated in the carbon capture absorption tower 6 enters the lean-rich liquid heat exchanger 9 and the regeneration tower 10 in sequence. The rich liquid in the regeneration tower 10 circulates into the reboiler 12 for heating and then returns to the regeneration tower 10.

[0043] The lean liquid generated in the regeneration tower 10 exchanges heat with the rich liquid in the lean-rich liquid heat exchanger 9, and then enters the carbon capture absorption tower 6 for reuse;

[0044] The regeneration gas generated in the regeneration tower 10 is compressed in the compressor 11;

[0045] The heating steam from the steam supply subsystem enters the compressor 11, the reboiler 12 and the lithium bromide absorption refrigerator 4 in sequence.

[0046] In the present invention, the flue gas carbon capture system includes a carbon capture subsystem and a steam supply subsystem, wherein the carbon capture subsystem is used to complete the process of capturing carbon in the flue gas, and the steam supply system is used to provide heat to the carbon capture system.

[0047] In the present invention, before the flue gas enters the carbon capture absorption tower 6, the flue gas is cooled in advance using a lithium bromide absorption refrigerator 4, which can effectively reduce the water content of the flue gas, ensure the temperature of the carbon capture system, and effectively improve the carbon capture efficiency.

[0048] In a preferred embodiment, the carbon capture subsystem further includes a carbon capture induced draft fan 3 for conveying the flue gas to be treated to the lithium bromide absorption chiller 4 .

[0049] In a specific embodiment, the flue gas outlet of the lithium bromide absorption refrigerator 4 is connected to the flue gas inlet of the carbon capture absorption tower 6, and the flue gas inlet of the lithium bromide absorption refrigerator 4 is connected to the carbon capture induced draft fan 3; the flue gas to be treated is introduced into the lithium bromide absorption refrigerator 4 through the carbon capture induced draft fan 3 for cooling treatment, and then the low-temperature flue gas obtained by the cooling treatment is transported to the flue gas inlet of the carbon capture absorption tower 6 through the flue gas outlet of the lithium bromide absorption refrigerator 4, and then enters the carbon capture absorption tower 6 for countercurrent contact reaction with the absorbent to form a rich liquid.

[0050] In the present invention, the rich liquid in the carbon capture absorption tower 6 is transported to the lean-rich liquid heat exchanger 9 via the rich liquid pump 1. Herein, the rich liquid is the lean liquid after absorbing CO2, and the lean liquid is the absorbent for absorbing CO2 in the carbon capture tower.

[0051] During specific implementation, the rich liquid outlet of the carbon capture absorption tower 6 is connected to the rich liquid inlet of the lean-rich liquid heat exchanger 9, and the rich liquid outlet of the lean-rich liquid heat exchanger 9 is connected to the rich liquid inlet of the regeneration tower, so that the rich liquid in the carbon capture absorption tower 6 can enter the regeneration tower 10 for regeneration.

[0052] In a specific embodiment, the rich liquid outlet of the regeneration tower 10 is connected to the reboiler 12, so that the rich liquid in the regeneration tower 10 circulates into the reboiler 12 for heating and then returns to the regeneration tower 10. In this way, the rich liquid in the regeneration tower 10 can be heated by the reboiler 12, causing the rich liquid in the regeneration tower 10 to undergo a desorption reaction to release CO2, thereby regenerating the absorbent and obtaining a lean liquid. The lean liquid outlet of the regeneration tower 10 is sequentially connected to the lean liquid inlet of the lean-rich liquid heat exchanger 9 and the lean liquid inlet of the carbon capture absorption tower 6, so that the lean absorbent liquid regenerated in the regeneration tower 10 can be returned to the carbon capture absorption tower 6 for the next carbon capture cycle.

[0053] In a preferred embodiment, the system further includes a regeneration gas cooler 5 , and the regeneration gas generated in the regeneration tower 10 is first cooled in the regeneration gas cooler 5 before entering the compressor 11 .

[0054] The regeneration gas is at a high temperature when it is discharged from the regeneration tower 10 and can be used as a heat source to be input into the lithium bromide absorption chiller 4, further reducing energy consumption. Therefore, in a more preferred embodiment, the regeneration gas generated in the regeneration tower 10 passes through the lithium bromide absorption chiller 4 before entering the regeneration gas cooler 5.

[0055] In a specific embodiment, the lithium bromide absorption chiller 4 further comprises a second heat source input port and a second heat source output port. The second heat source input port is connected to the regeneration gas outlet of the regeneration tower 10, the second heat source output port is connected to the inlet of the regeneration gas cooler 5, and the regeneration gas cooler outlet is connected to the carbon dioxide inlet of the compressor 11.

[0056] In the present invention, the steam supply subsystem is used to provide heat to the carbon capture subsystem. To better utilize steam thermal energy and reduce energy consumption, the heating steam from the steam supply subsystem is sequentially fed into the compressor 11, the reboiler 12, and the lithium bromide absorption chiller 4. The heating steam enters the compressor 11, providing the energy required for regeneration gas compression, achieving primary steam utilization. The heating steam then enters the reboiler 12, exchanging heat with the rich liquid entering the reboiler 12, achieving secondary steam utilization. The heating steam is then fed into the lithium bromide absorption chiller 4 as a heat source, achieving tertiary steam utilization.

[0057] In a specific embodiment, the lithium bromide absorption refrigerator 4 further has a first heat source input port. The steam outlet of the compressor 11 is connected to the steam inlet of the reboiler 12, and the steam outlet of the reboiler 12 is connected to the first heat source input port of the lithium bromide absorption refrigerator 4.

[0058] In a preferred embodiment, the steam supply subsystem includes a desulfurization tower induced draft fan 2 and a heating main pipe 15. The heating steam introduced into the compressor 11 can be provided by the desulfurization tower induced draft fan 2 and / or the heating main pipe 15.

[0059] In a specific embodiment, the desulfurization tower induced draft fan 2 can be connected to the steam turbine 16, and the steam generated by the steam turbine is introduced through the desulfurization tower induced draft fan 2 and used as heating steam.

[0060] In a specific embodiment, the heating main pipe 15 can be connected to the high auxiliary header 17, and the steam generated by the high auxiliary header is introduced through the heating main pipe 15 and used as heating steam.

[0061] In a specific embodiment, the desulfurization tower induced draft fan 2 and the heating main pipe 15 are both connected to the steam inlet of the compressor 11 through pipelines. A first valve 13 is provided on the connecting pipeline between the desulfurization tower induced draft fan 2 and the compressor 11, and a second valve 14 is provided on the connecting pipeline between the heating main pipe 15 and the compressor 11.

[0062] In a specific embodiment, the system further includes a lean liquid cooler 8. The lean liquid, after heat exchange with the rich liquid in the lean-rich liquid heat exchanger 9, is cooled in the lean liquid cooler 8 before entering the carbon capture absorption tower 6. The lean liquid cooler 8 further cools the lean liquid after treatment in the rich liquid heat exchanger before being pumped to the carbon capture absorption tower 6 via the lean liquid pump 7 for further CO2 absorption.

[0063] A second aspect of the present invention provides a method for capturing carbon from flue gas, the method being implemented in a system comprising a carbon capture subsystem and a steam supply subsystem;

[0064] The carbon capture subsystem includes a lithium bromide absorption refrigerator 4, a carbon capture absorption tower 6, a lean and rich liquid heat exchanger 9, a regeneration tower 10, a compressor 11 and a reboiler 12;

[0065] The method includes:

[0066] The flue gas to be treated is cooled in the lithium bromide absorption refrigerator 4, and the generated low-temperature flue gas is carbon captured in the carbon capture absorption tower 6;

[0067] The rich liquid generated in the carbon capture absorption tower 6 sequentially enters the lean-rich liquid heat exchanger 9 and the regeneration tower 10. The rich liquid in the regeneration tower 10 circulates into the reboiler 12 for heating and then returns to the regeneration tower 10.

[0068] The rich liquid is regenerated in the regeneration tower 10, and the generated lean liquid exchanges heat with the rich liquid in the lean-rich liquid heat exchanger 7, and then enters the carbon capture absorption tower 2 for reuse;

[0069] The regeneration gas generated in the regeneration tower 10 is compressed in the compressor 11;

[0070] The steam from the steam supply subsystem enters the compressor 11, the reboiler 12 and the lithium bromide absorption refrigerator in sequence.

[0071] Preferably, the system further comprises a regeneration gas cooler 5, and the method further comprises: cooling the regeneration gas from the lithium bromide absorption chiller 4 in the regeneration gas cooler 5 before entering the compressor 11;

[0072] Preferably, the regeneration gas generated in the regeneration tower 10 passes through the lithium bromide absorption refrigerator 4 before entering the regeneration gas cooler 5 .

[0073] Preferably, the system further comprises a lean liquid cooler 8 , and the method further comprises: the lean liquid after heat exchange with the rich liquid in the lean-rich liquid heat exchanger 9 first enters the lean liquid cooler 8 for cooling before entering the carbon capture absorption tower 6 .

[0074] Preferably, the absorbent in the carbon capture absorption tower 6 is an alcoholamine absorption liquid;

[0075] Preferably, the flue gas to be treated is the flue gas from a coal-fired power plant after being subjected to wet electrostatic precipitator.

[0076] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0077] Use Figure 1 The flue gas carbon capture system shown was operated for the following examples.

[0078] Example 1

[0079] The flue gas to be treated (with a temperature of 41.1°C, a water content of 7.78%, and a carbon dioxide content of 14.18%, drawn from the desulfurization tower of the power plant) is introduced into the lithium bromide absorption chiller 4 via the carbon capture induced draft fan 3 for cooling to obtain low-temperature flue gas. The low-temperature flue gas is introduced from the lower part of the carbon capture absorption tower 6, and the alcoholamine absorption liquid (i.e., the lean liquid with a low CO2 load) is sprayed down from the top of the carbon capture absorption tower 6. The low-temperature flue gas and the alcoholamine absorption liquid directly contact and react, turning the alcoholamine absorption liquid into a rich liquid rich in CO2.

[0080] The rich liquid at the bottom of the carbon capture absorption tower 6 is transported to the lean-rich liquid heat exchanger 9 via the rich liquid pump 1, where it exchanges heat with the cold lean liquid from the regeneration tower 10, and then is injected into the regeneration tower 10. The rich liquid in the regeneration tower 10 circulates into the reboiler 12 for heating (heat exchange with heating steam) to cause the rich liquid to undergo a desorption reaction to release CO2, and then returns to the regeneration tower 10;

[0081] The lean liquid generated in the regeneration tower 10 is transported to the lean-rich liquid heat exchanger 9 to exchange heat with the rich liquid from the carbon capture absorption tower 6, and then transported to the lean liquid cooler 8 for further cooling. The lean liquid is then pumped by the lean liquid pump 7 into the carbon capture absorption tower 6 for the next carbon capture cycle.

[0082] The regeneration gas generated in the regeneration tower 10 is input into the lithium bromide absorption refrigerator 4 as a second heat source, and then output from the lithium bromide absorption refrigerator 4 to the regeneration gas cooler 5 for further cooling, and then enters the compressor 11 for compression;

[0083] The heating steam provided by the desulfurization tower induced draft fan 2 and the heating main pipe 15 enters the compressor 11 through the pipeline for utilization, and then continues to be transported to the reboiler 12 for heat exchange with the rich liquid, and finally is input into the lithium bromide absorption refrigerator 4 as the first heat source for utilization.

[0084] Testing revealed that the flue gas temperature at the inlet of lithium bromide absorption chiller 4 was 41.1°C, and at the outlet it was 28.3°C. Upon entering the carbon capture absorber, the flue gas had a CO2 content of 14.18%, a temperature of 28.5°C, and a water content of 3.59%. Calculations showed that after 50 lean liquid cycles, the CO2 concentration at the outlet of carbon capture absorber 6 was 2.12%, with a CO2 capture efficiency of 85.1%. The energy consumption for CO2 desorption was 2.68 GJ / tCO2.

[0085] Comparative Example 1

[0086] The method of Example 1 was followed, except that the flue gas identical to that of Example 1 was directly fed into the carbon capture absorption tower for treatment. Specifically, the difference between Comparative Example 1 and Example 1 lies in that the flue gas to be treated does not pass through the lithium bromide absorption chiller 4 for cooling but instead passes directly into the carbon capture absorption tower. The heating steam output from the reboiler 12 does not pass through the lithium bromide absorption chiller 4 for tertiary utilization. The regenerated gas generated in the regeneration tower 10 does not pass through the lithium bromide absorption chiller 4 but instead passes directly into the regeneration gas cooler 5.

[0087] Calculations show that after 50 lean liquid cycles, the CO2 concentration at the absorber outlet is 2.69%, with a CO2 capture rate of 80.2%. The energy consumption for CO2 desorption is 2.79 GJ / tCO2.

[0088] Comparing Example 1 with Comparative Example 1, it can be seen that further cooling the flue gas by using a lithium bromide absorption chiller effectively reduces the water content of the flue gas entering the carbon capture absorption tower, ensures the stability of the carbon capture system, and effectively improves the carbon capture efficiency of the coal-fired power plant; the carbon capture rate is increased by approximately 6.11%, and the desorption energy consumption is reduced by approximately 3.9%.

[0089] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A flue gas carbon capture system, characterized in that: The system includes a carbon capture subsystem and a steam supply subsystem; The carbon capture subsystem includes a carbon capture induced draft fan (3), a lithium bromide absorption refrigerator (4), a regeneration gas cooler (5), a carbon capture absorption tower (6), a lean-rich liquid heat exchanger (9), a regeneration tower (10), a compressor (11) and a reboiler (12); The carbon capture induced draft fan (3) is used to transport the flue gas to be treated to the lithium bromide absorption refrigerator (4), and the lithium bromide absorption refrigerator (4) is used to cool the flue gas to be treated. The low-temperature flue gas generated by the lithium bromide absorption refrigerator (4) is carbon captured in the carbon capture absorption tower (6); The rich liquid generated in the carbon capture absorption tower (6) enters the lean and rich liquid heat exchanger (9) and the regeneration tower (10) in sequence, and the rich liquid in the regeneration tower (10) circulates into the reboiler (12) for heating and then returns to the regeneration tower (10); The lean liquid generated in the regeneration tower (10) exchanges heat with the rich liquid in the lean-rich liquid heat exchanger (9), and then enters the carbon capture absorption tower (6) for reuse; The regeneration gas generated in the regeneration tower (10) first passes through the lithium bromide absorption refrigerator (4), then enters the regeneration gas cooler (5) for cooling, and then is compressed in the compressor (11); The heating steam from the steam supply subsystem sequentially enters the compressor (11), the reboiler (12) and the lithium bromide absorption refrigerator (4); The steam supply subsystem comprises a desulfurization tower induced draft fan (2) and a heating main pipe (15).

2. The carbon capture system according to claim 1, wherein: The system further comprises a lean liquid cooler (8), wherein the lean liquid after heat exchange with the rich liquid in the lean-rich liquid heat exchanger (9) first enters the lean liquid cooler (8) for cooling before entering the carbon capture absorption tower (6).

3. A method for capturing carbon from flue gas, characterized in that: The method is implemented in a system including a carbon capture subsystem and a steam supply subsystem; The carbon capture subsystem includes a lithium bromide absorption refrigerator (4), a regeneration gas cooler (5), a carbon capture absorption tower (6), a lean-rich liquid heat exchanger (9), a regeneration tower (10), a compressor (11) and a reboiler (12); The method includes: The flue gas to be treated is subjected to a cooling treatment in the lithium bromide absorption refrigeration machine (4), and the generated low-temperature flue gas is subjected to carbon capture in the carbon capture absorption tower (6); The rich liquid generated in the carbon capture absorption tower (6) enters the lean-rich liquid heat exchanger (9) and the regeneration tower (10) in sequence, and the rich liquid in the regeneration tower (10) circulates into the reboiler (12) for heating and then returns to the regeneration tower (10); The rich liquid is regenerated in the regeneration tower (10), and the generated lean liquid is heat-exchanged with the rich liquid in the lean-rich liquid heat exchanger (9), and then enters the carbon capture absorption tower (6) for reuse; The regeneration gas generated in the regeneration tower (10) first passes through the lithium bromide absorption refrigerator (4), then enters the regeneration gas cooler (5), and is then compressed in the compressor (11); The heating steam from the steam supply subsystem enters the compressor (11), the reboiler (12) and the lithium bromide absorption refrigerator in sequence.

4. The method according to claim 3, characterized in that The system further comprises a lean liquid cooler (8), and the method further comprises: the lean liquid after heat exchange with the rich liquid in the lean-rich liquid heat exchanger (9) first enters the lean liquid cooler (8) for cooling before entering the carbon capture absorption tower (6).

5. The method according to claim 3 or 4, characterized in that The absorbent in the carbon capture absorption tower (6) is an alcohol amine absorption liquid.

6. The method according to claim 3 or 4, characterized in that The flue gas to be treated is the flue gas generated by a coal-fired power plant and is obtained after denitrification and desulfurization.

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