A flue gas carbon dioxide capture system

Abstract

The present application relates to flue gas treatment technical field, disclose a kind of flue gas carbon dioxide capture system, the system includes absorption tower 1 and regeneration tower 2, the absorption tower 1 is used to absorb carbon dioxide in flue gas, the regeneration tower 2 is used to regenerate from the bottom of the absorption tower 1 cold rich liquid;The absorption tower 1 from bottom to top includes absorption section 11 and water washing section 12 for flue gas is successively treated, the middle part of the absorption section 11 is equipped with half rich liquid collector 13, liquid in the half rich liquid collector 13 enters half rich liquid cooler 14 and the cooled half rich liquid is sprayed into the lower part of the absorption section 11 by first nozzle 15 arranged in the lower part of the half rich liquid collector 13.The system proposes rich liquid grading flow process, combined with water washing section condensate reflux process, realize the comprehensive utilization of capture system condensate, while water washing section condensate reflux to regeneration tower is used to reduce the temperature of regeneration gas, recycle regeneration gas heat, reduce regeneration energy consumption.

Description

Technical Field

[0001] This invention relates to the field of flue gas treatment technology, and more specifically to a flue gas carbon dioxide capture system. Background Technology

[0002] A typical process flow for chemical absorption in power plants involves pretreatment towers for cooling, dust removal, and deep desulfurization and denitrification. The flue gas then enters the absorption tower where it comes into countercurrent contact with the lean absorbent for heat and mass transfer. After decarbonization, the flue gas is discharged into the atmosphere through the top of the absorption tower. The absorbent that absorbs carbon dioxide from the flue gas is called the rich absorbent. The cold rich absorbent at the bottom of the absorption tower is heated by a lean-rich absorbent heat exchanger and then sent to the desorption tower. A reboiler installed at the bottom of the desorption tower generates secondary steam to drive the regeneration of the hot rich absorbent. The regenerated gas is cooled by a regenerated gas cooler, and the wet saturated carbon dioxide gas undergoes compression, drying, and liquefaction. The tail gas from the absorption tower enters a water washing section for washing and cooling, and the condensate is returned to the absorption tower. The regenerated gas from the regeneration tower is cooled by a regenerated gas cooler and undergoes gas-liquid separation before returning to the regeneration tower. Current technology does not adequately cool the absorbent, resulting in a high absorbent temperature and poor absorption of carbon dioxide from the flue gas. Furthermore, it does not fully utilize the waste heat from the regenerated gas. Summary of the Invention

[0003] To overcome the aforementioned problems in the existing technology, the present invention provides a flue gas carbon dioxide capture system. This system proposes a rich liquid staged flow process, combined with a condensate recirculation process in the water washing section, to achieve comprehensive utilization of the condensate in the capture system. At the same time, the condensate in the water washing section is recirculated to the regeneration tower to reduce the temperature of the regenerated gas, recover the heat of the regenerated gas, and reduce the energy consumption of regeneration.

[0004] To achieve the above objectives, the present invention provides a carbon dioxide capture system for flue gas. The system includes an absorption tower and a regeneration tower. The absorption tower is used to absorb carbon dioxide from the flue gas, and the regeneration tower is used to regenerate the cold rich liquid from the bottom of the absorption tower. The absorption tower includes, from bottom to top, an absorption section and a water washing section for sequentially treating the flue gas. A semi-rich liquid collector is provided in the middle of the absorption section. The liquid in the semi-rich liquid collector enters the semi-rich liquid cooler, and the cooled semi-rich liquid is sprayed into the lower part of the absorption section through a first nozzle provided at the lower part of the semi-rich liquid collector.

[0005] Preferably, the system further includes a washing liquid supply unit, which includes a washing liquid storage tank and a washing liquid cooler. The washing liquid in the washing liquid storage tank is fed into the washing liquid cooler, and the cooled washing liquid at the outlet of the washing liquid cooler is fed into the washing section for reuse.

[0006] Preferably, the system further includes a washing pump, through which the washing liquid in the washing liquid storage tank is pumped into the washing liquid cooler.

[0007] Preferably, a washing liquid collector is provided at the bottom of the washing section, and the liquid in the washing liquid collector enters the washing liquid storage tank.

[0008] Preferably, the system further includes a cooling storage tank, wherein a portion of the cooling water washing liquid at the outlet of the water washing liquid cooler enters the cooling storage tank and mixes with the liquid in the semi-rich liquid collector before entering the semi-rich liquid cooler.

[0009] Preferably, the system further includes a semi-rich liquid pump, through which cooling water washing liquid from the cooling storage tank is fed into the semi-rich liquid cooler.

[0010] Preferably, the system includes a regenerated gas waste heat recovery unit, which includes a regenerated gas cooler and a gas-liquid separator. The regenerated gas flowing out from the top of the regeneration tower is input into the regenerated gas cooler and the cooled regenerated gas is input into the gas-liquid separator. The liquid at the outlet of the gas-liquid separator is input into the regeneration tower from the top of the regeneration tower.

[0011] Preferably, the system further includes a water pump, through which the liquid at the outlet of the gas-liquid separator is fed into the regeneration tower.

[0012] Preferably, the upper part of the regeneration tower is provided with a second nozzle, and the liquid at the outlet end of the gas-liquid separator is input into the regeneration tower through the second nozzle.

[0013] Preferably, a portion of the cooling washing liquid from the outlet of the washing liquid cooler enters the gas-liquid separator, mixes with the cooling regenerated gas from the outlet of the regenerated gas cooler, and is then fed into the regeneration tower from the top of the regeneration tower.

[0014] Preferably, the system includes a lean-rich liquid heat exchanger, in which cold rich liquid from the bottom of the absorption tower and hot lean liquid from the bottom of the regeneration tower exchange heat, and hot rich liquid output from the hot rich liquid outlet end of the lean-rich liquid heat exchanger is input into the regeneration tower from the middle of the regeneration tower.

[0015] Preferably, the system further includes a lean solution pump through which hot lean solution from the bottom of the regeneration tower is fed into the lean-rich solution heat exchanger.

[0016] Preferably, the system further includes a rich liquid pump, through which cold rich liquid from the bottom of the absorption tower is fed into the lean-rich liquid heat exchanger.

[0017] Preferably, a third nozzle is provided in the middle of the regeneration tower, and the hot rich liquid output from the hot rich liquid outlet end of the lean-rich liquid heat exchanger is input into the regeneration tower from the middle of the regeneration tower through the third nozzle.

[0018] Preferably, the system further includes a lean liquid cooler, wherein the lean liquid output from the lean liquid outlet end of the lean-rich liquid heat exchanger enters the lean liquid cooler for heat exchange, and the cold lean liquid from the cold lean liquid outlet end of the lean liquid cooler is input into the absorption tower from the top of the absorption section.

[0019] Preferably, a fourth nozzle is provided at the top of the absorption section, and the cold lean liquid at the outlet end of the lean liquid cooler is fed into the absorption tower from the top of the absorption section through the fourth nozzle.

[0020] Compared with the prior art, the present invention has at least the following advantages:

[0021] (1) The condensate from the tail gas of the absorption tower and the condensate from the regenerated gas are mixed and returned to the regeneration tower to improve the heat recovery rate of the regenerated gas.

[0022] (2) The tail gas washing and cooling water of the absorption tower is combined with interstage cooling to improve the interstage cooling process effect. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the flue gas carbon dioxide capture system described in this invention.

[0024] Explanation of reference numerals in the attached figures

[0025] 1 Absorption tower; 2 Regeneration tower; 3 Lean and rich liquid heat exchanger; 4 Lean liquid cooler; 11 Absorption section; 12 Washing section; 13 Semi-rich liquid collector; 14 Semi-rich liquid cooler; 15 First nozzle; 16 Washing liquid supply unit; 17 Washing liquid collector; 18 Fourth nozzle; 19 Washing pump; 20 Semi-rich liquid pump; 21 Regeneration gas waste heat recovery unit; 22 Second nozzle; 23 Third nozzle; 31 Hot rich liquid outlet; 32 Lean liquid outlet; 33 Lean liquid pump; 34 Rich liquid pump; 41 Cold lean liquid outlet; 211 Regeneration gas cooler; 212 Gas-liquid separator; 213 Water pump; 161 Washing liquid storage tank; 162 Washing liquid cooler; 163 Cooling storage tank. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0027] The endpoints and any values ​​of the ranges 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 endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0028] The flue gas carbon dioxide capture system provided by this invention, such as Figure 1 As shown, the system includes an absorption tower 1 and a regeneration tower 2. The absorption tower 1 is used to absorb carbon dioxide in the flue gas, and the regeneration tower 2 is used to regenerate the cold rich liquid from the bottom of the absorption tower 1.

[0029] In the flue gas carbon dioxide capture system of the present invention, the flue gas enters from the bottom of the absorption tower 1 and comes into countercurrent contact with the absorbent liquid in the absorption tower 1. The cold rich liquid that has absorbed carbon dioxide from the flue gas accumulates at the bottom of the absorption tower 1. The cold rich liquid is fed into the regeneration tower 2 and falls from top to bottom into the regeneration tower 2 for regeneration through a reboiler. Then, the regeneration gas containing carbon dioxide and water vapor flows out from the top of the regeneration tower 2, and the bottom of the regeneration tower is obtained as a hot lean liquid after carbon dioxide removal.

[0030] In the flue gas carbon dioxide capture system of the present invention, the absorption tower 1 includes, from bottom to top, an absorption section 11 and a water washing section 12 for sequentially treating the flue gas. A semi-rich liquid collector 13 is provided in the middle of the absorption section 11. The liquid in the semi-rich liquid collector 13 enters the semi-rich liquid cooler 14 and the cooled semi-rich liquid is sprayed into the lower part of the absorption section 11 through a first nozzle 15 provided at the lower part of the semi-rich liquid collector 13.

[0031] In the specific implementation process, the flue gas introduced from the bottom of the absorption tower 1 sequentially absorbs carbon dioxide in the absorption section 11. Then, the flue gas carrying carbon dioxide droplets continues upward into the water washing section 12 for water washing, absorbing the carbon dioxide entrained in the flue gas, while simultaneously absorbing the flue gas itself. A semi-rich liquid collector 13 is installed in the middle of the absorption section 11 to collect the semi-rich liquid obtained from the absorption section 11 after absorbing a small amount of carbon dioxide. The semi-rich liquid is then cooled outside the absorption tower 1 by the semi-rich liquid cooler 14, and finally sprayed into the absorption section 11 through the first nozzle 15. The cooled semi-rich liquid has enhanced adsorption capacity for carbon dioxide and continues to mix with the flue gas containing a high concentration of carbon dioxide, which can improve the adsorption effect. This interstage cooling method can improve the adsorption effect of carbon dioxide in flue gas.

[0032] In a specific embodiment of the flue gas carbon dioxide capture system of the present invention, the system further includes a washing liquid supply unit 16. The washing liquid supply unit 16 includes a washing liquid storage tank 161 and a washing liquid cooler 162. The washing liquid in the washing liquid storage tank 161 is fed into the washing liquid cooler 162, and the cooled washing liquid at the outlet of the washing liquid cooler 162 is fed into the washing section 12 for reuse. The washing liquid in the washing liquid storage tank 161 is approximately 40°C. After being cooled in the washing liquid cooler 162, the temperature of the washing liquid is approximately 25°C. Reusing the cooled washing liquid in the washing section 12 improves the washing effect of the flue gas and better removes carbon dioxide.

[0033] In a specific embodiment, the system further includes a washing pump 19, through which the washing liquid in the washing liquid storage tank 161 is pumped into the washing liquid cooler 162. The washing pump 19 can be a conventional choice in the art, such as a booster pump.

[0034] In the flue gas carbon dioxide capture system of the present invention, a washing liquid collector 17 is provided at the bottom of the washing section 12, and the liquid in the washing liquid collector 17 enters the washing liquid storage tank 161. In the system of the present invention, after the flue gas is treated by the absorption section 11, the flue gas only carries a small amount of carbon dioxide. In the washing section 12, the solution obtained after the washing liquid washes the flue gas contains only a small amount of carbon dioxide, which can be collected and recycled, thereby saving resources. The washing liquid collector 17 at the bottom of the washing section 12 can collect the liquid in the washing section 12 and pass it into the washing liquid storage tank 161 as washing liquid. It is then fed into the washing liquid cooler 162 for cooling, and the cooled washing liquid at the outlet of the washing liquid cooler 162 is circulated back into the washing section 12 for reuse.

[0035] In a specific embodiment of the flue gas carbon dioxide capture system of the present invention, the system further includes a cooling storage tank 163. A portion of the cooling washing liquid from the outlet of the washing liquid cooler 162 enters the cooling storage tank 163 and mixes with the liquid in the semi-rich liquid collector 13 before entering the semi-rich liquid cooler 14. The cooling washing liquid from the outlet of the washing liquid cooler 162 can be entirely recycled into the washing section 12, or a portion can enter the cooling storage tank 163 and mix with the liquid from the semi-rich liquid collector 13 before entering the semi-rich liquid cooler 14 for cooling and then entering the absorption section 11 to absorb carbon dioxide from the flue gas.

[0036] In a specific embodiment, the system further includes a semi-rich liquid pump 20, through which cooling water washing liquid from the cooling storage tank 163 is input into the semi-rich liquid cooler 14. The semi-rich liquid pump 20 can be a conventional choice in the art, such as a booster pump.

[0037] In the flue gas carbon dioxide capture system of the present invention, the system includes a regeneration gas waste heat recovery unit 21, which includes a regeneration gas cooler 211 and a gas-liquid separator 212. The regeneration gas flowing out from the top of the regeneration tower 2 is input into the regeneration gas cooler 211 and the cooled regeneration gas is input into the gas-liquid separator 212. The liquid at the outlet of the gas-liquid separator 212 is input into the regeneration tower 2 from the upper part of the regeneration tower 2. The regeneration gas containing carbon dioxide and water vapor flowing out from the top of the regeneration tower 2 is cooled by the regeneration gas cooler 211, and the water vapor becomes liquid water. Then, the cooled regeneration gas still has a high temperature and enters the gas-liquid separator 212 for gas-liquid separation. The carbon dioxide is discharged into the atmosphere or used elsewhere, while the water with a high temperature is returned to the regeneration tower 2 for reuse.

[0038] In a specific embodiment, the system further includes a water pump 213, through which the liquid at the outlet of the gas-liquid separator 212 is input into the regeneration tower 2. The water pump 213 can be a conventional choice in the art, such as a booster pump.

[0039] In a preferred embodiment, a second nozzle 22 is provided at the upper part of the regeneration tower 2, and the liquid (i.e., liquid water) at the outlet of the gas-liquid separator 212 is input into the regeneration tower 2 through the second nozzle 22. Using a nozzle to spray water from the outlet of the gas-liquid separator 212 into the regeneration tower 2 increases the mass transfer surface area, allowing for better contact and heat exchange between the water and the regeneration gas. The water entering the regeneration tower 2 has a certain temperature, thereby fully recovering the waste heat from the regeneration gas and reducing regeneration energy consumption.

[0040] In the flue gas carbon dioxide capture system of the present invention, in a specific embodiment, a portion of the cooling water washing liquid from the outlet of the water washing liquid cooler 162 enters the gas-liquid separator 212 and mixes with the cooling regeneration gas from the outlet of the regeneration gas cooler 211, and is then fed into the regeneration tower 2 from the top. In a specific embodiment, a portion of the cooling water washing liquid and the cooling regeneration gas can be mixed in the gas-liquid separator 212 for gas-liquid separation according to actual needs, allowing a portion of the cooling water washing liquid to absorb heat from the regeneration gas. The resulting liquid is then fed into the regeneration tower 2, which can provide the required water for rich liquid regeneration and also fully recover the heat of the regeneration gas, reducing regeneration energy consumption.

[0041] In the flue gas carbon dioxide capture system of the present invention, in a preferred embodiment, the system includes a lean-rich liquid heat exchanger 3. Cold rich liquid from the bottom of the absorption tower 1 and hot lean liquid from the bottom of the regeneration tower 2 exchange heat in the lean-rich liquid heat exchanger 3. The hot rich liquid output from the hot rich liquid outlet 31 of the lean-rich liquid heat exchanger 3 is input into the regeneration tower 2 from the middle. The cold rich liquid from the bottom of the absorption tower 1 has a lower temperature, while the hot lean liquid from the bottom of the regeneration tower 2 has a higher temperature. The heat exchange between the cold rich liquid and the hot lean liquid in the lean-rich liquid heat exchanger 3 transforms the cold rich liquid into a hot rich liquid with a higher temperature. The hot rich liquid entering the regeneration tower 2 for regeneration can save regeneration energy.

[0042] In a specific embodiment, the system further includes a lean solution pump 33, through which hot lean solution from the bottom of the regeneration tower 2 is pumped into the lean-rich solution heat exchanger 3. The lean solution pump 33 can be a conventional choice in the art, such as a booster pump.

[0043] In a specific embodiment, the system further includes a rich liquid pump 34, through which cold rich liquid from the bottom of the absorption tower 1 is introduced into the lean-rich liquid heat exchanger 3. The rich liquid pump 34 can be a conventional choice in the art, such as a booster pump.

[0044] In the flue gas carbon dioxide capture system of the present invention, in a specific embodiment, a third nozzle 23 is provided in the middle of the regeneration tower 2. The hot rich liquid output from the hot rich liquid outlet 31 of the lean-rich liquid heat exchanger 3 is input into the regeneration tower 2 from the middle of the regeneration tower 2 through the third nozzle 23. By using a nozzle to spray the hot rich liquid into the regeneration tower 2, the mass transfer specific surface area of ​​the spray particles can be increased, thereby improving the regeneration effect.

[0045] In the flue gas carbon dioxide capture system of the present invention, in a preferred embodiment, the system further includes a lean liquid cooler 4. The lean liquid output from the lean liquid outlet 32 ​​of the lean-rich liquid heat exchanger 3 enters the lean liquid cooler 4 for heat exchange, and the cold lean liquid from the cold lean liquid outlet 41 of the lean liquid cooler 4 is fed into the absorption tower 1 from the top of the absorption section 11. The lean liquid obtained after heat exchange in the lean-rich liquid heat exchanger 3 is sent to the lean liquid cooler 4 for cooling. The cold lean liquid (absorbent) enters the absorption section 11 to absorb carbon dioxide in the flue gas, and the absorption capacity of the absorbent is stronger.

[0046] In the flue gas carbon dioxide capture system of the present invention, in a specific embodiment, a fourth nozzle 18 is provided at the top of the absorption section 11. The cold lean liquid from the cold lean liquid outlet 41 of the lean liquid cooler 4 is input into the absorption tower 1 from the top of the absorption section 11 through the fourth nozzle 18. By using a nozzle to spray the cold lean liquid into the absorption section 11, the mass transfer specific surface area of ​​the spray particles can be increased, thereby improving the absorption effect of carbon dioxide in the flue gas.

[0047] In one specific embodiment, the flue gas carbon dioxide capture system includes an absorption tower 1 and a regeneration tower 2. The absorption tower 1 is used to absorb carbon dioxide in the flue gas, and the regeneration tower 2 is used to regenerate the cold rich liquid from the bottom of the absorption tower 1. The absorption tower 1 includes, from bottom to top, an absorption section 11 and a water washing section 12 for sequentially treating the flue gas. A semi-rich liquid collector 13 is provided in the middle of the absorption section 11. The liquid in the semi-rich liquid collector 13 enters the semi-rich liquid cooler 14, and the cooled semi-rich liquid is sprayed into the lower part of the absorption section 11 through a first nozzle 15 provided at the lower part of the semi-rich liquid collector 13. The system also includes a water washing liquid supply unit 16, which includes a water washing liquid storage tank 161 and a water washing liquid cooler 162. The water washing liquid in the water washing liquid storage tank 161 is fed into the water washing liquid cooler 162, and the cooled water washing liquid at the outlet of the water washing liquid cooler 162 is fed into the water washing section 12 for reuse.

[0048] In a second specific embodiment, the flue gas carbon dioxide capture system includes an absorption tower 1 and a regeneration tower 2. The absorption tower 1 is used to absorb carbon dioxide in the flue gas, and the regeneration tower 2 is used to regenerate the cold rich liquid from the bottom of the absorption tower 1. The absorption tower 1 includes an absorption section 11 and a water washing section 12 from bottom to top, which process the flue gas sequentially. A semi-rich liquid collector 13 is provided in the middle of the absorption section 11. The liquid in the semi-rich liquid collector 13 enters the semi-rich liquid cooler 14, and the cooled semi-rich liquid is sprayed into the lower part of the absorption section 11 through a first nozzle 15 provided at the lower part of the semi-rich liquid collector 13. The system also includes a washing liquid supply unit 16, which includes a washing liquid storage tank 161 and a washing liquid cooler 162. The washing liquid in the washing liquid storage tank 161 is fed into the washing liquid cooler 162, and the cooled washing liquid at the outlet of the washing liquid cooler 162 is fed into the washing section 12 for reuse. The system also includes a washing pump 19, which feeds the washing liquid in the washing liquid storage tank 161 into the washing liquid cooler 162. A washing liquid collector 17 is provided at the bottom of the washing section 12, and the liquid in the washing liquid collector 17 enters the washing liquid storage tank 161.

[0049] In a third specific embodiment, the flue gas carbon dioxide capture system includes an absorption tower 1 and a regeneration tower 2. The absorption tower 1 is used to absorb carbon dioxide from the flue gas, and the regeneration tower 2 is used to regenerate the cold rich liquid from the bottom of the absorption tower 1. The absorption tower 1 includes, from bottom to top, an absorption section 11 and a water washing section 12 for sequentially treating the flue gas. A semi-rich liquid collector 13 is provided in the middle of the absorption section 11. The liquid in the semi-rich liquid collector 13 enters the semi-rich liquid cooler 14, and the cooled semi-rich liquid is sprayed into the water washing system through a first nozzle 15 provided at the bottom of the semi-rich liquid collector 13. The system includes the lower part of the absorption section 11; the system also includes a washing liquid supply unit 16, which includes a washing liquid storage tank 161 and a washing liquid cooler 162. The washing liquid in the washing liquid storage tank 161 is fed into the washing liquid cooler 162, and the cooled washing liquid at the outlet of the washing liquid cooler 162 is fed into the washing section 12 for reuse; the system also includes a cooling storage tank 163, in which part of the cooled washing liquid at the outlet of the washing liquid cooler 162 enters the cooling storage tank 163 and mixes with the liquid in the semi-rich liquid collector 13 before entering the semi-rich liquid cooler 14.

[0050] In a fourth specific embodiment, the flue gas carbon dioxide capture system includes an absorption tower 1 and a regeneration tower 2. The absorption tower 1 is used to absorb carbon dioxide from the flue gas, and the regeneration tower 2 is used to regenerate the cold rich liquid from the bottom of the absorption tower 1. The absorption tower 1 includes, from bottom to top, an absorption section 11 and a water washing section 12 for sequentially treating the flue gas. A semi-rich liquid collector 13 is provided in the middle of the absorption section 11. The liquid in the semi-rich liquid collector 13 enters the semi-rich liquid cooler 14 and cools the semi-rich liquid. The liquid is sprayed into the lower part of the absorption section 11 through the first nozzle 15 provided at the lower part of the semi-rich liquid collector 13; the system includes a regeneration gas waste heat recovery unit 21, which includes a regeneration gas cooler 211 and a gas-liquid separator 212. The regeneration gas flowing out from the top of the regeneration tower 2 is input into the regeneration gas cooler 211 and the cooled regeneration gas is input into the gas-liquid separator 212. The liquid at the outlet end of the gas-liquid separator 212 is input into the regeneration tower 2 from the upper part of the regeneration tower 2.

[0051] In the fifth specific embodiment, the flue gas carbon dioxide capture system includes an absorption tower 1 and a regeneration tower 2. The absorption tower 1 is used to absorb carbon dioxide in the flue gas, and the regeneration tower 2 is used to regenerate the cold rich liquid from the bottom of the absorption tower 1. The absorption tower 1 includes, from bottom to top, an absorption section 11 and a water washing section 12 for sequentially treating the flue gas. A semi-rich liquid collector 13 is provided in the middle of the absorption section 11. The liquid in the semi-rich liquid collector 13 enters the semi-rich liquid cooler 14 and the cooled semi-rich liquid is passed through the semi-rich liquid cooler 14. A first nozzle 15 located at the lower part of the rich liquid collector 13 sprays into the lower part of the absorption section 11; the system includes a lean-rich liquid heat exchanger 3, in which the cold rich liquid from the bottom of the absorption tower 1 and the hot lean liquid from the bottom of the regeneration tower 2 exchange heat, and the hot rich liquid output from the hot rich liquid outlet 31 of the lean-rich liquid heat exchanger 3 is input into the regeneration tower 2 from the middle part; the system also includes a rich liquid pump 34, through which the cold rich liquid from the bottom of the absorption tower 1 is pumped into the lean-rich liquid heat exchanger 3.

[0052] In the sixth specific embodiment, the flue gas carbon dioxide capture system includes an absorption tower 1 and a regeneration tower 2. The absorption tower 1 is used to absorb carbon dioxide in the flue gas, and the regeneration tower 2 is used to regenerate the cold rich liquid from the bottom of the absorption tower 1.

[0053] The absorption tower 1 includes, from bottom to top, an absorption section 11 and a water washing section 12 for sequentially treating flue gas. A semi-rich liquid collector 13 is provided in the middle of the absorption section 11. The liquid in the semi-rich liquid collector 13 enters the semi-rich liquid cooler 14 and the cooled semi-rich liquid is sprayed into the lower part of the absorption section 11 through a first nozzle 15 provided at the lower part of the semi-rich liquid collector 13. The system further includes a washing liquid supply unit 16, which includes a washing liquid storage tank 161 and a washing liquid cooler 162. The washing liquid in the washing liquid storage tank 161 is fed into the washing liquid cooler 162, and the cooled washing liquid at the outlet of the washing liquid cooler 162 is fed into the washing section 12 for reuse. The system also includes a washing pump 19, through which the washing liquid in the washing liquid storage tank 161 is fed into the washing liquid cooler 162. A washing liquid collector 17 is provided at the bottom of the washing section 12, and the liquid in the washing liquid collector 17 enters the washing liquid storage tank 161. The system also includes a cooling storage tank 163, in which part of the cooled washing liquid at the outlet of the washing liquid cooler 162 enters the cooling storage tank 163 and mixes with the liquid in the semi-rich liquid collector 13 before entering the semi-rich liquid cooler 14. The system also includes a semi-rich liquid pump 20, through which cooling water washing liquid from the cooling storage tank 163 is input into the semi-rich liquid cooler 14; the system includes a regeneration gas waste heat recovery unit 21, which includes a regeneration gas cooler 211 and a gas-liquid separator 212, through which regeneration gas flowing out from the top of the regeneration tower 2 is input into the regeneration gas cooler 211 and the cooled regeneration gas is input into the gas-liquid separator 212, and the liquid at the outlet of the gas-liquid separator 212 is input into the regeneration tower 2 from the upper part of the regeneration tower 2; the system also includes a water pump 213, through which the liquid at the outlet of the gas-liquid separator 212 is input into the regeneration tower 2; the upper part of the regeneration tower 2 is provided with a second nozzle 22, through which the liquid at the outlet of the gas-liquid separator 212 is input into the regeneration tower 2. Part of the cooling washing liquid from the outlet of the washing liquid cooler 162 enters the gas-liquid separator 212 and mixes with the cooling regenerated gas from the outlet of the regenerated gas cooler 211, and is then fed into the regeneration tower 2 from the top. The system includes a lean-rich liquid heat exchanger 3, in which the cold rich liquid from the bottom of the absorption tower 1 and the hot lean liquid from the bottom of the regeneration tower 2 exchange heat. The hot rich liquid output from the hot rich liquid outlet 31 of the lean-rich liquid heat exchanger 3 is fed into the regeneration tower 2 from the middle.The system also includes a lean liquid pump 33, through which hot lean liquid from the bottom of the regeneration tower 2 is pumped into the lean-rich liquid heat exchanger 3; the system also includes a rich liquid pump 34, through which cold rich liquid from the bottom of the absorption tower 1 is pumped into the lean-rich liquid heat exchanger 3. A third nozzle 23 is provided in the middle of the regeneration tower 2, through which hot rich liquid output from the hot rich liquid outlet 31 of the lean-rich liquid heat exchanger 3 is input into the regeneration tower 2 from the middle. The system also includes a lean liquid cooler 4, through which lean liquid output from the lean liquid outlet 32 ​​of the lean-rich liquid heat exchanger 3 enters the lean liquid cooler 4 for heat exchange, and cold lean liquid from the cold lean liquid outlet 41 of the lean liquid cooler 4 is input into the absorption tower 1 from the top of the absorption section 11. The top of the absorption section 11 is provided with a fourth nozzle 18, and the cold lean liquid from the cold lean liquid outlet end 41 of the lean liquid cooler 4 is fed into the absorption tower 1 from the top of the absorption section 11 through the fourth nozzle 18.

[0054] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A flue gas carbon dioxide capture system, characterized in that, The system includes an absorption tower (1) and a regeneration tower (2), wherein the absorption tower (1) is used to absorb carbon dioxide in flue gas and the regeneration tower (2) is used to regenerate the cold rich liquid from the bottom of the absorption tower (1); The absorption tower (1) includes, from bottom to top, an absorption section (11) and a water washing section (12) for sequentially treating flue gas. A semi-rich liquid collector (13) is provided in the middle of the absorption section (11). The liquid in the semi-rich liquid collector (13) enters the semi-rich liquid cooler (14) and the cooled semi-rich liquid is sprayed into the lower part of the absorption section (11) through a first nozzle (15) provided at the lower part of the semi-rich liquid collector (13). The system also includes a washing liquid supply unit (16), which includes a washing liquid storage tank (161) and a washing liquid cooler (162). The washing liquid in the washing liquid storage tank (161) is fed into the washing liquid cooler (162), and the cooled washing liquid at the outlet of the washing liquid cooler (162) is fed into the washing section (12) for reuse. The system also includes a cooling tank (163), and part of the cooling water washing liquid at the outlet end of the water washing liquid cooler (162) enters the cooling tank (163) and mixes with the liquid in the semi-rich liquid collector (13) before entering the semi-rich liquid cooler (14). The system includes a regenerated gas waste heat recovery unit (21), which includes a regenerated gas cooler (211) and a gas-liquid separator (212). The regenerated gas flowing out from the top of the regeneration tower (2) is input into the regeneration gas cooler (211) and the cooled regenerated gas is input into the gas-liquid separator (212). The liquid at the outlet of the gas-liquid separator (212) is input into the regeneration tower (2) from the top of the regeneration tower (2). Part of the cooling washing liquid from the outlet of the washing liquid cooler (162) enters the gas-liquid separator (212) and mixes with the cooling regenerated gas from the outlet of the regenerated gas cooler (211) and is fed into the regeneration tower (2) from the top.

2. The system of claim 1, wherein, The system also includes a washing pump (19), through which the washing liquid in the washing liquid storage tank (161) is pumped into the washing liquid cooler (162).

3. The system of claim 1, wherein, The bottom of the washing section (12) is provided with a washing liquid collector (17), and the liquid in the washing liquid collector (17) enters the washing liquid storage tank (161).

4. The system of claim 2, wherein, The system also includes a semi-rich liquid pump (20), through which cooling water washing liquid from the cooling storage tank (163) is fed into the semi-rich liquid cooler (14).

5. The system of claim 2, wherein, The system also includes a water pump (213), through which the liquid at the outlet of the gas-liquid separator (212) is fed into the regeneration tower (2).

6. The system of claim 2, wherein, The upper part of the regeneration tower (2) is provided with a second nozzle (22), and the liquid at the outlet end of the gas-liquid separator (212) is input into the regeneration tower (2) through the second nozzle (22).

7. The system of claim 1, wherein, The system includes a lean-rich liquid heat exchanger (3), in which the cold rich liquid from the bottom of the absorption tower (1) and the hot lean liquid from the bottom of the regeneration tower (2) exchange heat. The hot rich liquid output from the hot rich liquid outlet end (31) of the lean-rich liquid heat exchanger (3) is input into the regeneration tower (2) from the middle.

8. The system of claim 7, wherein, The system also includes a lean liquid pump (33) through which hot lean liquid from the bottom of the regeneration tower (2) is fed into the lean-rich liquid heat exchanger (3).

9. The system of claim 7, wherein, The system also includes a rich liquid pump (34), through which cold rich liquid from the bottom of the absorption tower (1) is fed into the lean and rich liquid heat exchanger (3).

10. The system of claim 9, wherein, The regeneration tower (2) is provided with a third nozzle (23) in the middle. The hot rich liquid output from the hot rich liquid outlet end (31) of the lean and rich liquid heat exchanger (3) is input into the regeneration tower (2) from the middle through the third nozzle (23).

11. The system of claim 9, wherein, The system also includes a lean liquid cooler (4), in which the lean liquid output from the lean liquid outlet end (32) of the lean-rich liquid heat exchanger (3) enters the lean liquid cooler (4) for heat exchange and the cold lean liquid from the cold lean liquid outlet end (41) of the lean liquid cooler (4) is fed into the absorption tower (1) from the top of the absorption section (11).

12. The system of claim 11, wherein, The top of the absorption section (11) is provided with a fourth nozzle (18), and the cold lean liquid from the cold lean liquid outlet end (41) of the lean liquid cooler (4) is fed into the absorption tower (1) from the top of the absorption section (11) through the fourth nozzle (18).

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