CN214635242U

CN214635242U - Carbon dioxide capture and low condensation water adding coupling system

Info

Publication number: CN214635242U
Application number: CN202120685541.8U
Authority: CN
Inventors: 王争荣; 孙路长; 王凯亮; 汪洋; 吴冲; 张丽亚
Original assignee: China Huadian Engineering Group Co Ltd; Huadian Environmental Protection Engineering and Technology Co Ltd
Current assignee: China Huadian Engineering Group Co Ltd; Huadian Environmental Protection Engineering and Technology Co Ltd
Priority date: 2021-04-02
Filing date: 2021-04-02
Publication date: 2021-11-09
Anticipated expiration: 2031-04-02

Abstract

The utility model provides a carbon dioxide entrapment and low condensation water coupled system that adds belongs to carbon dioxide entrapment technical field, include: the system comprises an absorption tower, a regeneration tower and a reboiler, wherein the regeneration tower is communicated with rich liquid in the absorption tower through a pipeline, a crude gas exhaust port is formed in the regeneration tower, a first cooling heat exchanger is communicated with the rear end of the crude gas exhaust port of the regeneration tower, and the first cooling heat exchanger is communicated with a low-pressure condensate water pipeline of a power plant; the utility model discloses a carbon dioxide entrapment adds condensate water coupled system with low, and the coarse gas vent rear end intercommunication at the regenerator column has first cooling heat exchanger, and this first cooling heat exchanger adds the condensate water intercommunication with the low of power plant for the condensate water that adds to getting into low heats, thereby reduces and bleeds through the steam turbine and to the power consumption of condensate water heating, reduces the power consumption of carbon dioxide entrapment system on the whole, thereby reaches energy-conserving purpose.

Description

Carbon dioxide capture and low condensation water adding coupling system

Technical Field

The utility model relates to a carbon dioxide entrapment technical field, concretely relates to carbon dioxide entrapment and low condensation water coupled system that adds.

Background

CCS technology is an abbreviation for Carbon Capture and Storage, a technology that captures and sequesters Carbon dioxide (CO 2). The CCS technology is a carbon capture technology that separates carbon dioxide produced by industry and related energy industries, and then transports and stores the separated carbon dioxide to places isolated from the atmosphere, such as the sea floor or the underground, by means of carbon storage.

CCS technology consists of two parts, carbon capture and carbon sequestration. Among them, the carbon capture technology is applied to industries such as oil refining and chemical industry for the earliest time. Due to the high concentration and pressure of CO2 emitted by these industries, the capture cost is not high. The opposite is true for CO2 emitted from coal-fired power plants, and carbon dioxide capture from power plant emissions has problems of high energy consumption and high cost.

The energy consumption of the carbon dioxide capture system is mainly the regeneration steam consumption of the regeneration tower, because the temperature difference between the lean solution at the bottom of the regeneration tower and the regeneration gas at the top of the regeneration tower is not large, the heat contained in the lean solution at the bottom of the regeneration tower and the heat contained in the regeneration gas at the top of the regeneration tower are relatively close, if the heat is recovered by the rich solution at the bottom of the absorption tower, the heat recovery of one stream in the lean solution at the bottom of the tower or the regenerator at the top of the tower can only be realized, the temperature difference between the heated rich solution and the temperature of the other stream is not large, the heat recovery of the other stream can not be realized, and the other stream can only be cooled by circulating cooling water at present, so that about half of the heat is wasted.

SUMMERY OF THE UTILITY MODEL

Therefore, the to-be-solved technical problem of the utility model lies in overcoming the too high defect of energy consumption of the carbon dioxide entrapment system for power plant among the prior art to provide a carbon dioxide entrapment and low condensation water coupled system that adds.

In order to solve the technical problem, the utility model provides a carbon dioxide entrapment and low condensation water coupled system that adds, include:

one end of the absorption tower is communicated with a flue gas outlet of the power plant, the absorption tower is suitable for containing absorption liquid, and the absorption liquid in the absorption tower absorbs carbon dioxide in the flue gas and then becomes rich liquid;

the regeneration tower is communicated with rich liquid in the absorption tower through a pipeline, a crude gas exhaust port is formed in the regeneration tower, the rear end of the crude gas exhaust port of the regeneration tower is communicated with a first cooling heat exchanger, and the first cooling heat exchanger is communicated with a low-pressure condensate pipeline of a power plant;

and the reboiler is communicated with the regeneration tower and is used for vaporizing the rich liquid entering the regeneration tower into a gas-liquid two-phase state, wherein the liquid phase is changed into a lean liquid, and the gas phase is discharged from a crude gas exhaust port of the regeneration tower.

Optionally, a cooling water inlet of the first cooling heat exchanger is communicated with an outlet of the condenser, and a cooling water outlet of the first cooling heat exchanger is communicated with the low-pressure condensate inlet.

Optionally, the absorption tower is provided with a self-circulation pipeline, one end of the self-circulation pipeline is communicated with the tower bottom absorption liquid of the absorption tower, and the other end of the self-circulation pipeline is communicated with the tower top inner cavity of the absorption tower.

Optionally, a self-circulation heat exchanger is arranged on the self-circulation pipeline.

Optionally, a spraying device is arranged on an outlet of one end of the self-circulation pipeline, which leads to the tower top inner cavity of the absorption tower.

Optionally, a tail gas emptying port is arranged on the absorption tower, a tail gas heat exchanger is arranged at the front end of the tail gas emptying port, and the tail gas heat exchanger is arranged above the self-circulation pipeline.

Optionally, a demister is further arranged at the front end of the tail gas evacuation port of the absorption tower.

Optionally, a demister is arranged at the front end of the raw gas exhaust port of the regeneration tower.

Optionally, the crude gas exhaust port of the regeneration tower is communicated with a gas-liquid separator, and the separated water of the gas-liquid separator flows back into the regeneration tower.

Optionally, a second cooling heat exchanger is further disposed at the rear end of the first cooling heat exchanger, and the separated water discharged from the gas-liquid separator is firstly used as cooling water of the second cooling heat exchanger and then flows back to the regeneration tower.

The utility model discloses technical scheme has following advantage:

1. the utility model provides a carbon dioxide entrapment and low condensation water coupled system that adds has first cooling heat exchanger in the coarse gas vent rear end intercommunication of regeneration tower, and this first cooling heat exchanger and the low condensation water intercommunication that adds of power plant for the condensation water that adds to getting into low heats, thereby reduces and bleeds through the steam turbine and to the power consumption of condensation water heating, reduces the power consumption of carbon dioxide entrapment system on the whole, thereby reaches energy-conserving purpose.

The utility model provides a low pressure heater indicates low pressure heater, and low pressure heater's effect is the steam that utilizes to do partial work in the steam turbine, takes out to the heater internal heating feedwater, improves the temperature of water, has reduced the steam volume that the steam turbine discharged to the condenser, has reduced energy loss, improves thermodynamic system's circulation efficiency.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic diagram of a carbon dioxide capture and low condensed water coupling system provided in an embodiment of the present invention.

Fig. 2 is a schematic diagram of the carbon dioxide capture system of fig. 1.

Fig. 3 is a schematic diagram of a second embodiment of a carbon dioxide capture system provided in an example of the present invention.

Description of reference numerals:

1. a boiler; 2. a high pressure turbine; 3. a medium pressure steam turbine; 4. a low pressure turbine; 5. a condenser;

6. a low pressure heat exchanger; 7. a deaerator; 8. a high pressure heater; 9. a reboiler; 10. pre-washing the tower; 11.

an absorption tower; 12. a regeneration tower; 13. a crude gas vent; 14. a first cooling heat exchanger; 15. a flue gas inlet;

16. a booster fan; 17. a pre-washing pump; 18. a washing liquid heat exchanger; 19. a pH value detection element; 20.

a self-circulating pump; 21. a self-circulating heat exchanger; 22. a tail gas evacuation port; 23. a tail gas heat exchanger; 24. pregnant solution

A supply pipe; 25. a barren liquor return pipe; 26. a lean-rich liquid heat exchanger; 27. a barren liquor heat exchanger; 28. gas-liquid separation

Separating from the device; 29. a second cooling heat exchanger.

Detailed Description

The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Furthermore, the technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

The embodiment provides a carbon dioxide capture and low condensed water coupling system, as shown in fig. 1, comprising: a carbon dioxide capture system and a low condensed water system. The thermodynamic system of a power plant comprises: boiler 1, high pressure steam turbine 2, medium pressure steam turbine 3, low pressure steam turbine 4, condenser 5, low heat exchanger 6 that adds, oxygen-eliminating device 7 and high heat exchanger 8 that adds, thermodynamic system is coal fired power plant's entire system that utilizes coal combustion electricity generation, the steam turbine burns in boiler 1 and produces steam, steam gets into the steam turbine and generates electricity, steam after the electricity generation condenses to water through condenser 5, add through low, oxygen-eliminating device 7 and high heating cycle recycles to boiler 1, circulate in proper order and realize continuous power generation. Among the devices through which the steam from the steam turbine passes in sequence, the low-pressure heater 6 located between the condenser 5 and the deaerator 7 is provided with a plurality of low-pressure heaters, and a system formed by the plurality of low-pressure heaters 6 is called a low-pressure heater system in this embodiment.

As shown in fig. 1, the carbon dioxide capturing system includes a reboiler 9, and the reboiler 9 heats the rich liquid in the regeneration tower 12 to precipitate crude carbon dioxide gas in the rich liquid. The reboiler 9 extracts heat by extracting air from the low pressure turbine 4, and then the heat-exchanged steam becomes condensed water, which is sent to the deaerator 7. In addition, the carbon dioxide capturing system further includes a first cooling heat exchanger 14 at the top of the regeneration tower 12, and the first cooling heat exchanger 14 cools the raw carbon dioxide gas, also referred to as a regeneration gas, precipitated from the regeneration tower 12. The cooling water of the first cooling heat exchanger 14 is low-temperature condensate of the power plant, that is, before the condensate from the condenser enters the low-temperature condensate exchanger 6, at least part of the condensate enters the first cooling heat exchanger 14 of the carbon dioxide system, and the condensate is used for cooling the regeneration gas separated out from the regeneration tower 12, so as to achieve the purpose of utilizing the residual heat of the regeneration gas. And the waste heat of the regenerated gas is used for heating the low-pressure condensate water, so that part of the heat consumption of the low-pressure heat exchanger 6 is saved, and the heating steam of the low-pressure heat exchanger 6 is extracted from the steam turbine, so that part of the heat is returned to the steam turbine by utilizing the waste heat of the regenerated gas, the steam consumption of the carbon dioxide capture system is reduced on the whole, and particularly, by adopting the carbon dioxide capture and low-pressure condensate water coupling system, the whole steam consumption can be reduced by 30% -40%.

As shown in fig. 2, the present embodiment provides a carbon dioxide capture system including: a prewash column 10, an absorption column 11 and a regeneration column 12. The regeneration tower 12 is provided with a crude gas exhaust port 13, the rear end of the crude gas exhaust port 13 of the regeneration tower 12 is communicated with a first cooling heat exchanger 14, and the regeneration tower is communicated with a low condensed water pipeline of a power plant through the first cooling heat exchanger 14; that is, the cooling water inlet of the first cooling heat exchanger 14 is communicated with part of low condensed water, and the cooling water outlet of the first cooling heat exchanger 14 is communicated with the deaerator 7; or the cooling water outlet of the first cooling heat exchanger 14 is communicated with part of the low heat exchanger 6, so that the function of the part of the low heat exchanger 6 is replaced by the first cooling heat exchanger 14, and the air extraction amount of the steam turbine is saved.

The prewashing tower 10 is provided with a flue gas inlet 15, the flue gas inlet 15 is used for communicating with flue gas after desulfurization, and the flue gas enters the prewashing tower 10 through the flue gas inlet 15. The prewashing tower 10 is mainly used for removing trace acid gases in the flue gas, reducing the temperature of the flue gas through circulating spraying of alkali liquor, and reducing the moisture content and the volume of the flue gas. At the top of the pre-scrubber 10 there is an outlet which is connected to the inlet of the absorber 11 via a booster fan 16. The pre-washing tower 10 is provided with a circulating pipeline, two ends of the circulating pipeline are respectively communicated with the bottom end and the top end of the pre-washing tower 10, the circulating pipeline is connected with a pre-washing pump 17, washing liquid in the pre-washing tower 10 is conveyed to the tower top from the tower bottom through the pre-washing pump 17, and the washing liquid returns to the tower bottom again in the tower top in a spraying mode; during the process that the flue gas flows from the flue gas inlet 15 to the flue gas outlet in the pre-washing tower 10, the flue gas and the washing liquid flow in a convection manner, so that the flue gas is pre-washed by the washing liquid. In addition, as a preferred embodiment, a washing liquid heat exchanger 18 is further connected to the circulation pipeline, and the washing liquid heat exchanger 18 is used for cooling the washing liquid, so as to control the outlet flue gas temperature of the prewashing tower, namely the inlet temperature of the absorption tower 11, and adjust the water balance of the absorption liquid of the absorption and collection system. In addition, as a preferred embodiment, a PH value detecting element 19 is further connected in parallel to the circulating pipeline, and the PH value detecting element 19 is used for detecting the PH value of the washing solution in real time so as to supplement the alkaline washing solution in time.

As shown in fig. 2, an inlet at one end of the absorption tower 11 is connected with an outlet of the pre-washing tower 10 so as to communicate with flue gas of the thermal power plant, and the inside of the absorption tower 11 is adapted to contain an absorption liquid, and the absorption liquid in the absorption tower 11 becomes a rich liquid after absorbing carbon dioxide in the flue gas. Specifically, the absorption tower 11 is provided with a self-circulation pipeline, one end of the self-circulation pipeline leads to the tower bottom absorption liquid of the absorption tower 11, the other end of the self-circulation pipeline leads to the tower top inner cavity of the absorption tower 11, a spraying device is arranged at an outlet of one end of the self-circulation pipeline, which leads to the tower top inner cavity of the absorption tower 11, and the absorption liquid is sprayed downwards from the tower top through the spraying device so as to be fully contacted with the flue gas. The self-circulation pipeline is provided with a self-circulation heat exchanger 21 and a self-circulation pump 20, the self-circulation heat exchanger 21 is used for cooling the absorbent, and the self-circulation pump 20 is used for keeping the circulation flow of the absorption liquid. The temperature in the absorption tower 11 is controlled by the absorption tower 11 through the heat exchange of the self-circulation heat exchanger 21, the lower temperature and the higher pressure are more beneficial to the absorption of carbon dioxide by the absorbent, the absorption liquid at the bottom of the absorption tower 11 is pumped out to the self-circulation heat exchanger 21 from the circulating pump 20 on a self-circulation pipeline arranged outside the absorption tower 11 to exchange heat with cooling circulation water, the cooled absorption liquid can be sent to the top of the absorption tower 11 or the middle part of the absorption tower 11, the cold absorption liquid is contacted with the flue gas in the absorption tower 11 to exchange heat, so that the tower temperature of the absorption tower 11 is controlled, the absorption capacity of the absorption liquid per unit mass is increased, and the absorption capacity of the absorption liquid is changed by controlling the tower temperature of the absorption tower 11 through the self-circulation system.

As shown in fig. 2, the absorption tower 11 is provided with a tail gas vent 22, a tail gas heat exchanger 23 is provided at the front end of the tail gas vent 22, the tail gas heat exchanger 23 is disposed above the spray opening of the self-circulation pipeline, and the temperature of the flue gas discharged from the absorption tower 11 is reduced by the tail gas heat exchanger 23. Specifically, the tail gas heat exchanger 23 is a wide-channel plate heat exchanger, the escape rate of the absorbent from the top of the absorption tower 11 can be reduced through the plate heat exchanger, and the wide-channel plate heat exchanger has the advantages of small heat exchange end difference, large heat exchange coefficient and the like. The cooling circulating water exchanges heat with the flue gas through the partition wall, the temperature of the flue gas at the top of the absorption tower 11 is saturated flue gas, moisture is separated out after the heat exchange with the cooling circulating water, absorption liquid carried in the flue gas is also separated out, and the separated moisture and the absorbent flow back to the absorption tower 11 along the heat exchange wall of the plate heat exchanger for recycling. In addition, the absorption tower 11 is further provided with a demister between the tail gas heat exchanger 23 and the tail gas evacuation port 22, and the demister is used for reducing the water content in the flue gas.

As shown in fig. 2, the regeneration tower 12 is communicated with the rich liquid in the absorption tower 11 through a rich liquid supply pipe 24, one end of the rich liquid supply pipe 24 extends into the absorption tower 11 from the tower bottom of the absorption tower 11, the other end of the rich liquid supply pipe 24 extends into the regeneration tower 12 from the tower top of the regeneration tower 12, the rich liquid enters the tower top of the regeneration tower 12 from the absorption tower 11, and is sprayed downward from the inside of the tower top of the regeneration tower 12 in a spraying manner, so that the carbon dioxide gas contained in the rich liquid is precipitated. Further, a lean liquid return pipe 25 is connected between the regeneration tower 12 and the absorption tower 11, one end of the lean liquid return pipe 25 is connected to the inside of the bottom end of the regeneration tower 12, and the other end of the lean liquid return pipe 25 is connected to the inside of the top of the absorption tower 11, and the lean liquid return pipe is sprayed in the top of the absorption tower 11 by a spraying method. In addition, the lean liquid return pipe 25 and the rich liquid supply pipe 24 are connected through a lean-rich liquid heat exchanger 26, that is, after the hot lean liquid in the lean liquid return pipe 25 transfers heat to the rich liquid in the rich liquid supply pipe 24 through the lean-rich liquid heat exchanger 26, the lean liquid in the lean liquid return pipe 25 returns to the absorption tower 11 again, so as to recover the heat of the lean liquid in the regeneration tower 12; in addition, the rich solution is heated by the lean solution in the lean and rich solution heat exchanger 26 and then enters the top of the regeneration tower 12, the reboiler 9 is arranged at the bottom of the regeneration tower 12, steam used by the reboiler 9 comes from a steam turbine to extract, the steam turbine extracts heat and condenses in the reboiler 9, condensed water returns to the thermodynamic system deaerator 7, exhaust gas at the top of the regeneration tower 12 exchanges heat with low-pressure condensate water, and the low-pressure condensate water is heated by the exhaust gas of the regeneration tower 12 and then is sent to the low-pressure condenser at the downstream, so that the condensate water is preheated, the steam turbine extraction used by the low-pressure heat exchanger 6 is reduced or is not used at all, and the waste heat recovery of the regenerated gas of the carbon dioxide capture system is realized. In addition, the lean solution return pipe 25 is provided with a lean solution heat exchanger 27, and the lean solution is cooled by the lean solution heat exchanger 27 to recover the absorption of the absorption liquid for the carbon dioxide in the flue gas.

As shown in fig. 2, the regeneration tower 12 has a raw gas exhaust port 13 at the top thereof, and a demister is provided at the front end of the raw gas exhaust port 13 for reducing the water content in the exhaust gas. The raw gas exhaust port 13 of the regeneration tower 12 communicates with a gas-liquid separator 28, and the separated water of the gas-liquid separator 28 can flow back into the regeneration tower 12. In addition, the separated water discharged from the gas-liquid separator 28 may be sent to a desulfurization system of a power plant for reuse, if excessive.

As shown in fig. 2, the regeneration tower 12 communicates with a reboiler 9, and the reboiler 9 vaporizes the rich liquid introduced into the regeneration tower 12 into a gas-liquid two-phase, and also, carbon dioxide gas in the rich liquid is precipitated by heating to change the rich liquid into a lean liquid, and the carbon dioxide gas in the rich liquid is discharged from a raw gas exhaust port 13 of the regeneration tower 12. The reboiler 9 can be understood as a heat exchanger, and the reboiler 9 is in communication with the steam extraction so as to heat the absorption liquid by the steam extraction.

As shown in fig. 2, the raw gas exhaust port 13 of the regeneration tower 12 is communicated with a first cooling heat exchanger 14, and the first cooling heat exchanger 14 is used for exchanging heat with low condensed water, so as to achieve heat recovery of carbon dioxide saturated gas precipitated in the regeneration tower 12. In addition, a second cooling heat exchanger 29 is further arranged at the rear end of the first cooling heat exchanger 14, and the second cooling heat exchanger 29 is used for further recovering the heat of the carbon dioxide saturated gas.

As shown in fig. 3, as a preferred embodiment, the separated water discharged from the gas-liquid separator 28 is first used as the cooling water of the second cooling heat exchanger 29, and then returned to the regeneration tower 12, thereby further recovering heat from the carbon dioxide gas.

The gas discharged from the gas-liquid separator 28 is compressed by a compressor and then used, thereby completing the capture of carbon dioxide in the flue gas. The carbon dioxide capture and low condensed water coupling system provided by the embodiment can realize gradient utilization of energy of extracted steam, reduce the steam consumption of the whole carbon dioxide capture and low condensed water coupling system, and reduce the steam consumption for capturing carbon dioxide by 30-40%.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious changes and modifications may be made without departing from the scope of the present invention.

Claims

1. A carbon dioxide capture and low condensed water coupling system, comprising:

one end of the absorption tower (11) is communicated with a flue gas outlet of the power plant, the absorption tower is suitable for containing absorption liquid, and the absorption liquid in the absorption tower (11) absorbs carbon dioxide in the flue gas and then becomes rich liquid;

the regeneration tower (12) is communicated with rich liquid in the absorption tower (11) through a pipeline, a crude gas exhaust port (13) is formed in the regeneration tower (12), a first cooling heat exchanger (14) is communicated with the rear end of the crude gas exhaust port (13) of the regeneration tower (12), and the first cooling heat exchanger (14) is communicated with a low-pressure condensate water pipeline of a power plant;

and the reboiler (9) is communicated with the regeneration tower (12) and is used for vaporizing the rich liquid entering the regeneration tower (12) into a gas-liquid two-phase state, wherein the liquid phase is changed into a lean liquid, and the gas phase is discharged from a crude gas exhaust port (13) of the regeneration tower (12).

2. The carbon dioxide capture and low-charge condensate water coupling system according to claim 1, wherein a cooling water inlet of the first cooling heat exchanger (14) is in communication with an outlet of a condenser (5), and a cooling water outlet of the first cooling heat exchanger (14) is in communication with a low-charge condensate water inlet.

3. The carbon dioxide capture and low-condensed water coupling system according to claim 1, wherein the absorption tower (11) is provided with a self-circulation pipeline, one end of the self-circulation pipeline is opened into the absorption liquid at the bottom of the absorption tower (11), and the other end of the self-circulation pipeline is opened into the inner cavity at the top of the absorption tower (11).

4. The carbon dioxide capture and low condensate water coupling system of claim 3, wherein the self-circulating pipeline is provided with a self-circulating heat exchanger (21).

5. The carbon dioxide capture and low condensed water coupling system according to claim 3, wherein a spray device is arranged on an outlet of one end of the self-circulation pipeline, which is led to the tower top inner cavity of the absorption tower (11).

6. The carbon dioxide capturing and low condensed water adding coupling system according to claim 3, wherein the absorption tower (11) is provided with a tail gas evacuation port (22), the front end of the tail gas evacuation port (22) is provided with a tail gas heat exchanger (23), and the tail gas heat exchanger (23) is arranged above the self-circulation pipeline.

7. The carbon dioxide capture and low condensed water coupling system according to claim 6, wherein the front end of the tail gas exhaust port (22) of the absorption tower (11) is further provided with a demister.

8. The carbon dioxide capture and low-condensed water coupling system according to any one of claims 1 to 7, wherein a front end of the raw gas exhaust port (13) of the regeneration tower (12) is provided with a demister.

9. The carbon dioxide capture and low-condensate water coupling system according to any one of claims 1-7, wherein the raw gas vent (13) of the regeneration column (12) is in communication with a gas-liquid separator (28), and separated water of the gas-liquid separator (28) is refluxed into the regeneration column (12).

10. The carbon dioxide capture and low-condensed water coupling system according to claim 9, wherein a second cooling heat exchanger (29) is further provided at the rear end of the first cooling heat exchanger (14), and the separated water discharged from the gas-liquid separator (28) is firstly used as cooling water of the second cooling heat exchanger (29) and then is refluxed into the regeneration tower (12).