Carbon dioxide regeneration system and carbon dioxide regeneration method

Abstract

The invention relates to the technical field of carbon dioxide capture, in particular to a carbon dioxide regeneration system and a carbon dioxide regeneration method. The carbon dioxide regeneration system comprises a regeneration tower, a reboiler, a regeneration gas cooler, a temperature and pressure reducer, a regeneration gas heat exchanger and a superheated steam pipeline, a barren liquor outlet in the bottom of the regeneration tower is communicated with an inlet of the body part of the reboiler through an eighth circulating pump, and the top of the regeneration tower is communicated with an inlet of a regenerated gas cooler; the superheated steam pipeline is communicated with an inlet of the heating part of the reboiler through the temperature and pressure reducer; an outlet of the heating part of the reboiler is communicated with an inlet of the heating part of the regeneration gas heat exchanger through a second circulating pump; a liquid outlet of the regeneration gas cooler is communicated with an inlet of a body part of the regeneration gas heat exchanger, and an outlet of the body part of the regeneration gas heat exchanger is communicated with the top of the regeneration tower through a third circulating pump. The carbon dioxide regeneration system can prevent the regeneration efficiency of the carbon dioxide gas from being reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide capture, and in particular to a carbon dioxide regeneration system and a carbon dioxide regeneration method. Background Art

[0002] After the flue gas of the power plant has been cooled, dust-removed, and subjected to deep desulfurization and denitrification in the pretreatment tower, it will enter the absorption tower and contact with the lean absorbent liquid and conduct heat and mass transfer to complete the decarbonization of the flue gas. After decarbonization, the flue gas is discharged into the atmosphere through the top outlet of the absorption tower. The lean absorbent liquid absorbs the carbon dioxide gas and heat in the flue gas and is then converted into a rich absorbent liquid. The rich absorbent liquid will enter the regeneration tower, and the carbon dioxide gas can be precipitated from the rich absorbent liquid in the regeneration tower, so that the rich absorbent liquid is converted into a lean absorbent liquid in the regeneration tower, and the carbon dioxide gas flows out from the top outlet of the regeneration tower. The carbon dioxide gas is then cooled and the water vapor mixed in the carbon dioxide gas is cooled and cooled to become regeneration gas condensate; the regeneration gas condensate is then returned to the regeneration tower; and the relatively pure carbon dioxide gas will enter the downstream processing device from the cooler for compression, drying, and liquefaction.

[0003] Since the temperature of the regenerated gas condensate formed after cooling is relatively low, the regeneration gas condensate flowing back into the regeneration tower will cause the temperature in the regeneration tower to drop, thereby reducing the efficiency of the absorbent rich liquid in precipitating carbon dioxide gas, that is, reducing the regeneration efficiency of the carbon dioxide gas. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem in the prior art that the reflux of low-temperature regeneration gas condensate into the regeneration tower will reduce the regeneration efficiency of carbon dioxide gas.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a carbon dioxide regeneration system on one hand, which includes a regeneration tower, a reboiler, a regeneration gas cooler, a temperature reduction and pressure reduction device, a regeneration gas heat exchanger and a superheated steam pipeline; a rich liquid inlet for the absorption agent rich liquid to enter is provided at the top of the regeneration tower, a lean liquid outlet at the bottom of the regeneration tower is connected to the inlet of the main body of the reboiler through an eighth circulation pump, and the top of the regeneration tower is connected to the inlet of the regeneration gas cooler; the outlet of the main body of the reboiler is connected to the first return port at the bottom of the regeneration tower; the superheated steam pipeline is connected to the inlet of the heating part of the reboiler through the temperature reduction and pressure reduction device, and a first circulation pump is provided on the superheated steam pipeline; the outlet of the heating part of the reboiler is connected to the inlet of the heating part of the regeneration gas heat exchanger through a second circulation pump, and the outlet of the heating part of the regeneration gas heat exchanger is used to communicate with the recovery pipeline; the liquid outlet of the regeneration gas cooler is connected to the inlet of the main body of the regeneration gas heat exchanger, and the outlet of the main body of the regeneration gas heat exchanger is connected to the top of the regeneration tower through a third circulation pump; the gas outlet of the regeneration gas cooler is used to communicate with a carbon dioxide gas processing device.

[0006] In some embodiments, a first atomizing nozzle is provided in the temperature-reducing and pressure-reducing device, and the first atomizing nozzle is connected to the heating part of the reboiler through a fourth circulation pump.

[0007] In some embodiments, the carbon dioxide regeneration system also includes a flash tank, a booster pump and a compressor, the inlet of the flash tank is connected to the lean liquid outlet at the bottom of the regeneration tower through the booster pump, the outlet of the flash tank is connected to the inlet of the compressor, the outlet of the compressor is connected to the second return port at the bottom of the regeneration tower, and the second return port is located above the liquid level of the absorbent lean liquid in the regeneration tower.

[0008] In some embodiments, a second atomizing nozzle is provided at the inlet of the compressor, and the second atomizing nozzle is connected to the heating part of the reboiler through a fifth circulation pump.

[0009] In some embodiments, the carbon dioxide regeneration system also includes an absorption tower, the rich liquid outlet at the bottom of the absorption tower is connected to the rich liquid inlet at the top of the regeneration tower through a sixth circulation pump, the lean liquid inlet at the top of the absorption tower is connected to the lean liquid outlet at the bottom of the regeneration tower through a seventh circulation pump, a flue gas outlet is provided at the top of the absorption tower, and a flue gas inlet is provided at the bottom of the absorption tower.

[0010] In some embodiments, the lean liquid inlet at the top of the absorption tower is connected to the liquid outlet of the regeneration gas cooler through the main body of the regeneration gas heat exchanger; and / or, the carbon dioxide regeneration system also includes a lean-rich liquid heat exchanger, the rich liquid outlet at the bottom of the absorption tower is connected to the rich liquid inlet at the top of the regeneration tower through the rich liquid transfer part of the lean-rich liquid heat exchanger, and the lean liquid inlet at the top of the absorption tower is connected to the lean liquid outlet at the bottom of the regeneration tower through the lean liquid transfer part of the lean-rich liquid heat exchanger.

[0011] On the other hand, the present invention also provides a carbon dioxide regeneration method, which includes: heating the absorbent rich liquid by a first heating steam, so that the absorbent rich liquid precipitates carbon dioxide gas and is converted into an absorbent lean liquid; at the same time, heating a portion of the absorbent lean liquid by superheated steam that has been reduced in temperature and pressure to a preset temperature and a preset pressure, so that the absorbent lean liquid generates the first heating steam that heats the absorbent rich liquid; and the superheated steam and the absorbent lean liquid are heat exchanged to form steam condensate with a preset temperature; cooling the carbon dioxide gas, so that the water vapor mixed in the carbon dioxide gas is cooled to become regenerated gas condensate and separated from the carbon dioxide gas; heat exchanging the steam condensate with the regenerated gas condensate to increase the temperature of the regenerated gas condensate; and returning the regenerated gas condensate with the increased temperature to the first heating steam.

[0012] In some embodiments, the carbon dioxide regeneration method also includes: flashing another portion of the absorbent lean liquid to form absorbent lean liquid steam; atomizing a portion of the steam condensate and further spraying it into the absorbent lean liquid steam to form a first mixed gas; compressing the first mixed gas to form a second heating steam; and allowing the second heating steam to enter the second heating steam and heat the absorbent rich liquid.

[0013] In some embodiments, the carbon dioxide regeneration method also includes: spraying another portion of steam condensate that has been atomized into the superheated steam to form a second mixed gas; reducing the temperature and pressure of the second mixed gas to form a third heated steam with a preset temperature and a preset pressure; allowing the third heated steam to heat a portion of the absorbent lean liquid, and the third heated steam that has completed the heat exchange is formed into steam condensate.

[0014] In some embodiments, the carbon dioxide regeneration method is performed using the carbon dioxide regeneration system of any of the above embodiments.

[0015] The technical solution of the present invention has the following beneficial effects:

[0016] After the superheated steam is cooled and depressurized by the desuperheater, a third heating steam will be formed. The third heating steam will enter the heating part of the reboiler to heat the absorbent lean liquid in the main body of the reboiler. The superheated steam that has completed heating the absorbent lean liquid will form steam condensate, which can enter the heating part of the regeneration gas heat exchanger; and the regeneration gas condensate separated from the carbon dioxide gas will enter the main body of the regeneration gas heat exchanger. Since the temperature of the steam condensate is higher than that of the regeneration gas condensate, the steam condensate can heat the regeneration gas condensate, and the regeneration gas condensate with increased temperature can be returned to the regeneration tower. Since the temperature of the regeneration gas condensate increases, the regeneration gas condensate refluxes to the regeneration tower without causing the temperature in the regeneration tower to decrease, thereby avoiding the reduction in the efficiency of the absorbent rich liquid to precipitate carbon dioxide gas. Therefore, the carbon dioxide regeneration system can avoid the reduction in the regeneration efficiency of carbon dioxide gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of a carbon dioxide regeneration system according to an embodiment of the present invention.

[0018] Description of Reference Numerals

[0019] 1. Regeneration tower; 2. Reboiler; 3. Temperature and pressure reducing device; 4. Regeneration gas cooler; 5. Regeneration gas heat exchanger; 6. Superheated steam pipeline; 7. Flash tank; 8. Compressor; 9. Absorption tower; 10. Lean and rich liquid heat exchanger; 11. First circulation pump; 12. Second circulation pump; 13. Third circulation pump; 14. Fourth circulation pump; 15. Fifth circulation pump; 16. Sixth circulation pump; 17. Seventh circulation pump; 18. Eighth circulation pump; 19. Booster pump. DETAILED DESCRIPTION

[0020] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present invention, rather than to limit the present invention. For those skilled in the art, the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention.

[0021] like Figure 1As shown, the present invention provides a carbon dioxide regeneration system, which includes a regeneration tower 1, a reboiler 2, a regeneration gas cooler 4, a temperature reduction and pressure reduction device 3, a regeneration gas heat exchanger 5 and a superheated steam pipeline 6; the top of the regeneration tower 1 is provided with a rich liquid inlet for the absorbent rich liquid to enter, the lean liquid outlet at the bottom of the regeneration tower 1 is connected to the inlet of the main body of the reboiler 2 through an eighth circulation pump 18, and the top of the regeneration tower 1 is connected to the inlet of the regeneration gas cooler 4; the outlet of the main body of the reboiler 2 is connected to the first return port at the bottom of the regeneration tower 1; the superheated steam pipeline 6 is connected to the regeneration tower 1 through the temperature reduction and pressure reduction device 3; the regeneration tower 1 is connected to the regeneration gas cooler 4 ... The reboiler 3 is connected with the inlet of the heating part of the reboiler 2, and a first circulating pump 11 is provided on the superheated steam pipeline 6; the outlet of the heating part of the reboiler 2 is connected with the inlet of the heating part of the regeneration gas heat exchanger 5 through the second circulating pump 12, and the outlet of the heating part of the regeneration gas heat exchanger 5 is used to be connected with the recovery pipeline; the liquid outlet of the regeneration gas cooler 4 is connected with the inlet of the main body of the regeneration gas heat exchanger 5, and the outlet of the main body of the regeneration gas heat exchanger 5 is connected with the top of the regeneration tower 1 through the third circulating pump 13; the gas outlet of the regeneration gas cooler 4 is used to be connected with the carbon dioxide gas processing device.

[0022] Specifically, the absorbent rich liquid enters the regeneration tower 1 through the rich liquid inlet at the top of the regeneration tower 1. There is a first heating steam in the regeneration tower 1, which can heat the absorbent rich liquid. After the absorbent rich liquid is heated, carbon dioxide gas is precipitated, and the absorbent rich liquid that precipitates carbon dioxide gas is converted into absorbent lean liquid, which will gather at the bottom of the regeneration tower 1. The absorbent lean liquid can gradually enter the main body of the reboiler 2. At the same time, the superheated steam with high temperature from the power plant enters the temperature reduction and pressure reduction device 3 through the superheated steam pipeline 6 for temperature reduction and pressure reduction. The temperature reduction and pressure reduction device 3 can reduce the temperature and pressure of the superheated steam to preset parameters to form the third heating steam, so as to prevent the superheated steam from damaging the reboiler 2 due to excessive temperature and pressure. The third heating steam can enter the heating part of the reboiler 2. Since the temperature of the third heating steam is higher than the temperature of the absorbent lean liquid, the third heating steam in the heating part of the reboiler 2 can heat the absorbent lean liquid in the body part of the reboiler 2, so that the absorbent lean liquid is evaporated by heat to form the first heating steam, and the first heating steam returns to the regeneration tower 1 through the first return port, thereby continuously heating the absorbent rich liquid in the regeneration tower 1; and the third heating steam that completes the heat exchange with the absorbent lean liquid will reduce the temperature and form steam condensed water with a still high temperature. A part of the absorbent lean liquid circulates in this way, and the absorbent rich liquid entering the regeneration tower 1 is continuously circulated and heated, so that the carbon dioxide gas is continuously regenerated, but the regenerated carbon dioxide gas is mixed with water vapor. The regenerated carbon dioxide gas will enter the regeneration gas cooler 4, and the regeneration gas cooler 4 can cool the carbon dioxide gas, so that the water vapor mixed in the carbon dioxide gas is cooled and cooled to become regeneration gas condensed water with a lower temperature, thereby separating the water vapor from the carbon dioxide gas. The relatively pure carbon dioxide gas enters the carbon dioxide gas processing device for compression, drying and liquefaction. The regeneration gas condensate can further enter the main body of the regeneration gas heat exchanger 5, and the steam condensate with a higher temperature can enter the heating part of the regeneration gas heat exchanger 5. Since the temperature of the steam condensate is higher than that of the regeneration gas condensate, the steam condensate can heat the regeneration gas condensate. The regeneration gas condensate with increased temperature can be returned to the regeneration tower 1, and the steam condensate after heat exchange enters the recovery pipeline.

[0023] In this embodiment, after the superheated steam is cooled and depressurized by the desuperheater 3, a third heating steam is formed. The third heating steam enters the heating part of the reboiler 2 to heat the absorbent lean liquid in the main body of the reboiler 2. The superheated steam that completes heating the absorbent lean liquid forms steam condensate, which can enter the heating part of the regeneration gas heat exchanger 5; and the regeneration gas condensate separated from the carbon dioxide gas enters the main body of the regeneration gas heat exchanger 5. Since the temperature of the steam condensate is higher than that of the regeneration gas condensate, the steam condensate can heat the regeneration gas condensate, and the regeneration gas condensate with the increased temperature can be returned to the regeneration tower 1. Since the temperature of the regeneration gas condensate is increased, the regeneration gas condensate flowing back to the regeneration tower 1 will not cause the temperature in the regeneration tower 1 to decrease, thereby avoiding the reduction in the efficiency of the absorbent rich liquid to precipitate carbon dioxide gas. Therefore, the carbon dioxide regeneration system can avoid the reduction in the regeneration efficiency of carbon dioxide gas.

[0024] In some embodiments, the temperature range of superheated steam is 285℃~295℃, and its pressure range is 0.6MPa~0.65MPa. In some embodiments, after the superheated steam is cooled and depressurized to form a third heating steam, the temperature range of the third heating steam is 140℃~148℃, and its pressure range is 0.27MPa~0.33MPa. In some embodiments, after the third heating steam and the absorbent lean liquid complete heat exchange, the third heating steam is cooled to form steam condensate, the temperature range of the steam condensate is 112℃-118℃, and the gas pressure range in the pipeline where the steam condensate is located is 0.27MPa~0.33MPa. In some embodiments, after the steam condensate is heat exchanged with the regenerated gas condensate, the temperature of the steam condensate is reduced, and at this time the temperature range of the steam condensate is 72℃-78℃, and the gas pressure range in the pipeline where it is located is still 0.27MPa~0.33MPa.

[0025] In some embodiments of the present invention, a first atomizing nozzle is provided in the temperature reducing and pressure reducing device 3 , and the first atomizing nozzle is connected to the heating part of the reboiler 2 through the fourth circulation pump 14 .

[0026] Specifically, the third heating steam that has completed heat exchange with the absorbent lean liquid will reduce its temperature to form steam condensate, and the first atomizing nozzle can atomize the steam condensate, and spray the atomized steam condensate into the superheated steam entering the desuperheater 3 to form a second mixed gas, and the desuperheater 3 can perform a desuperheating and decompression treatment on the second mixed gas. Since the temperature of the steam condensate is lower than that of the superheated steam, the steam condensate can cool the superheated steam, reduce the desuperheating and decompression treatment pressure of the desuperheater 3, and improve the thermal energy utilization rate of the superheated steam.

[0027] In some embodiments of the present invention, the carbon dioxide regeneration system further includes a flash tank 7, a booster pump 19 and a compressor 8, the inlet of the flash tank 7 is connected to the lean liquid outlet at the bottom of the regeneration tower 1 through the booster pump 19, the outlet of the flash tank 7 is connected to the inlet of the compressor 8, the outlet of the compressor 8 is connected to the second return port at the bottom of the regeneration tower 1, and the second return port is located above the liquid level of the absorbent lean liquid in the regeneration tower 1.

[0028] Specifically, a portion of the absorbent lean liquid in the regeneration tower 1 is pumped into the flash tank 7 by the booster pump 19, and the flash tank 7 can perform negative pressure flash vaporization on this portion of the absorbent lean liquid to make this portion of the absorbent lean liquid become absorbent lean liquid steam. These absorbent lean liquid steams can further enter the compressor 8, and the compressor 8 can compress these absorbent lean liquid steams. After compression, the absorbent lean liquid steam will be heated and pressurized to form a second heating steam, and then the second heating steam is returned to the regeneration tower 1. These second heating steams can replace a portion of the first heating steam, which helps to reduce the regeneration energy consumption.

[0029] In some embodiments of the present invention, a second atomizing nozzle is provided at the inlet of the compressor 8 , and the second atomizing nozzle is connected to the heating part of the reboiler 2 through a fifth circulation pump 15 .

[0030] Specifically, the third heating steam that has completed heat exchange with the absorbent lean liquid will reduce its temperature to form steam condensate. The second atomizing nozzle can atomize the steam condensate and spray it into the compressor 8, and mix it with the absorbent lean liquid steam to form a first mixed gas; the compressor 8 can compress the first mixed gas to form the second heating steam. Since the temperature of the atomized steam condensate is relatively low, the exhaust temperature of the compressor 8 can be reduced to prevent the second heating steam from exceeding the bearing temperature of the compressor 8. Moreover, applying steam condensate to the compressor 8 can also improve the thermal energy utilization rate of the superheated steam.

[0031] In some embodiments of the present invention, the carbon dioxide regeneration system also includes an absorption tower 9, the rich liquid outlet at the bottom of the absorption tower 9 is connected to the rich liquid inlet at the top of the regeneration tower 1 through a sixth circulation pump 16, the lean liquid inlet at the top of the absorption tower 9 is connected to the lean liquid outlet at the bottom of the regeneration tower 1 through a seventh circulation pump 17, a flue gas outlet is provided at the top of the absorption tower 9, and a flue gas inlet is provided at the bottom of the absorption tower 9.

[0032] Specifically, the flue gas can enter the bottom of the absorption tower 9 from the flue gas inlet, and the absorbent lean liquid at the bottom of the regeneration tower 1 can enter the top of the regeneration tower 1. The absorbent lean liquid can absorb the carbon dioxide gas in the flue gas and convert it into absorbent rich liquid. The absorbent rich liquid gathers at the bottom of the absorption tower 9, and the absorbent rich liquid enters the top of the regeneration tower 1 to perform carbon dioxide gas regeneration. The flue gas after decarbonization is discharged through the flue gas outlet.

[0033] In some embodiments of the present invention, the lean liquid inlet at the top of the absorption tower 9 is connected to the liquid outlet of the regeneration gas cooler 4 through the body portion of the regeneration gas heat exchanger 5;

[0034] Specifically, the regeneration gas condensate separated from the regeneration gas cooler 4 is relatively pure, so it can be used as absorbent lean liquid, so a part of the regeneration gas condensate can enter the absorption tower 9.

[0035] In some embodiments of the present invention, the carbon dioxide regeneration system also includes a lean-rich liquid heat exchanger 10, the rich liquid outlet at the bottom of the absorption tower 9 and the rich liquid inlet at the top of the regeneration tower 1 are connected via the rich liquid transport portion of the lean-rich liquid heat exchanger 10, and the lean liquid inlet at the top of the absorption tower 9 and the lean liquid outlet at the bottom of the regeneration tower 1 are connected via the lean liquid transport portion of the lean-rich liquid heat exchanger 10.

[0036] Specifically, the temperature of the absorbent lean liquid flowing from the regeneration tower 1 to the absorption tower 9 is higher than the temperature of the absorbent rich liquid flowing from the absorption tower 9 to the regeneration tower 1, so the absorbent lean liquid and then the absorbent rich liquid can be heat exchanged through the lean-rich liquid heat exchanger 10, on the one hand, the temperature of the absorbent lean liquid is reduced so that it can absorb more carbon dioxide gas; on the other hand, the temperature of the absorbent rich liquid is increased to accelerate the efficiency of the absorbent rich liquid in precipitating carbon dioxide gas. Preferably, the sixth circulation pump 16 is arranged on the pipeline between the lean-rich liquid heat exchanger 10 and the regeneration tower 1, and the seventh circulation pump 17 is arranged on the pipeline between the lean-rich liquid heat exchanger 10 and the absorption tower 9.

[0037] It should be noted that, for the regeneration tower 1, the reboiler 2, the regeneration gas cooler 4, the temperature and pressure reducer 3, the regeneration gas heat exchanger 5, the first atomizing nozzle, the second atomizing nozzle, the flash tank 7, the booster pump 19, the compressor 8, the absorption tower 9, the lean and rich liquid heat exchanger 10 and all the above-mentioned circulating pumps, the present invention can adopt any structural form in the field that can achieve the above-mentioned technical effects, and the present invention is not limited thereto.

[0038] The present invention also provides a carbon dioxide regeneration method, which includes: heating the absorbent rich liquid by a first heating steam, so that the absorbent rich liquid precipitates carbon dioxide gas and is converted into an absorbent lean liquid; at the same time, superheated steam that has been reduced in temperature and pressure to a preset temperature and a preset pressure is used to heat a portion of the absorbent lean liquid, so that the absorbent lean liquid generates the first heating steam that heats the absorbent rich liquid; and the superheated steam and the absorbent lean liquid are heat exchanged to form steam condensate with a preset temperature; cooling the carbon dioxide gas, so that the water vapor mixed in the carbon dioxide gas is cooled to become regenerated gas condensate and separated from the carbon dioxide gas; heat exchanging the steam condensate with the regenerated gas condensate to increase the temperature of the regenerated gas condensate; and returning the regenerated gas condensate with the increased temperature to the first heating steam.

[0039] Specifically, the first heating steam can heat the absorbent rich liquid, and the absorbent rich liquid precipitates carbon dioxide gas after being heated, and the absorbent rich liquid that precipitates carbon dioxide gas is converted into the absorbent lean liquid. At the same time, the superheated steam with high temperature is cooled and depressurized to form the third heating steam. Since the temperature of the third heating steam is higher than the temperature of the absorbent lean liquid, the third heating steam can heat a part of the absorbent lean liquid, so that the absorbent lean liquid is heated and evaporated to form the first heating steam, and the first heating steam returns to the absorbent rich liquid to heat the absorbent rich liquid. The third heating steam that completes the heat exchange with the absorbent lean liquid will reduce the temperature and form steam condensate water that still has a high temperature. A part of the absorbent lean liquid is circulated in this way, and the absorbent rich liquid is continuously circulated and heated, so that the carbon dioxide gas is continuously regenerated, but the regenerated carbon dioxide gas is mixed with water vapor. The carbon dioxide gas is cooled, so that the water vapor mixed in the carbon dioxide gas is cooled and cooled to become regenerated gas condensate water with a lower temperature, thereby separating the water vapor from the carbon dioxide gas. The relatively pure carbon dioxide gas is compressed, dried and liquefied. Since the temperature of steam condensate is higher than that of regenerated gas condensate, steam condensate can heat the regenerated gas condensate. The regenerated gas condensate with increased temperature can be returned to the first heating steam, and the steam condensate after heat exchange is recovered.

[0040] In this embodiment, after the superheated steam is cooled and depressurized, a third heating steam is formed, which heats a portion of the absorbent lean liquid. The superheated steam that has completed heating the absorbent lean liquid forms steam condensate, which can heat the regeneration gas condensate separated from the carbon dioxide gas. The regeneration gas condensate with the increased temperature can be returned to the first heating steam. Since the temperature of the regeneration gas condensate increases, the regeneration gas condensate flowing back to the first heating steam will not cause the temperature of the first heating steam to decrease, thereby avoiding a decrease in the efficiency of the absorbent rich liquid to precipitate carbon dioxide gas, that is, avoiding a decrease in the regeneration efficiency of carbon dioxide gas.

[0041] In some embodiments of the present invention, the carbon dioxide regeneration method also includes: flashing another portion of the absorbent lean liquid to form absorbent lean liquid steam; atomizing a portion of the steam condensate and further spraying it into the absorbent lean liquid steam to form a first mixed gas; compressing the first mixed gas to form a second heating steam; and allowing the second heating steam to enter the second heating steam and heat the absorbent rich liquid.

[0042] Specifically, a portion of the absorbent lean liquid is flash-vaporized at negative pressure to make this portion of the absorbent lean liquid become absorbent lean liquid steam. The third heating steam that completes heat exchange with the absorbent lean liquid will reduce its temperature to form steam condensate. A portion of the steam condensate is atomized and sprayed into the absorbent lean liquid steam to form a first mixed gas. The first mixed gas is compressed to form a second heating steam. Since the temperature of the steam condensate is relatively low, the temperature of the second heating steam can be appropriately reduced to prevent the temperature of the second heating steam from exceeding the bearing temperature of related equipment. The second heating steam is allowed to enter the second heating steam and heat the absorbent rich liquid. These second heating steams can replace a portion of the first heating steam, which helps to reduce the regeneration energy consumption and improve the thermal energy utilization rate of the superheated steam.

[0043] In some embodiments of the present invention, the carbon dioxide regeneration method also includes: spraying another portion of steam condensate that has been atomized into the superheated steam to form a second mixed gas; reducing the temperature and pressure of the second mixed gas to form a third heating steam with a preset temperature and a preset pressure; allowing the third heating steam to heat a portion of the absorbent lean liquid, and the third heating steam that has completed the heat exchange is formed into steam condensate.

[0044] Specifically, the third heating steam that has completed heat exchange with the absorbent lean liquid will reduce its temperature to form steam condensate, a portion of which is atomized and sprayed into the superheated steam to form a second mixed gas. The temperature of the second mixed gas is lower than that of the superheated steam, which reduces the pressure of the temperature reduction and pressure reduction process and makes full use of the temperature characteristics of the steam condensate. The second mixed gas is reduced in temperature and pressure to form the third heating steam, which heats the absorbent lean liquid, and the third heating steam that has completed heat exchange with the absorbent lean liquid forms steam condensate.

[0045] In some embodiments of the present invention, the carbon dioxide regeneration method can be performed using the carbon dioxide regeneration system of any of the above embodiments. Of course, the carbon dioxide regeneration method can also be implemented using other systems, which is not limited by the present invention.

[0046] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. The above are only preferred implementation methods of the present invention. It should be pointed out that due to the limitations of textual expression, there are objectively infinite specific structures. For ordinary technicians in this technical field, without departing from the principles of the present invention, they can make several improvements, modifications or changes, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concept and technical solution of the present invention to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. A carbon dioxide regeneration system, characterized in that: It comprises a regeneration tower (1), a reboiler (2), a regeneration gas cooler (4), a temperature and pressure reducing device (3), a regeneration gas heat exchanger (5) and a superheated steam pipeline (6); The top of the regeneration tower (1) is provided with a rich liquid inlet for the absorbent rich liquid to enter, the lean liquid outlet at the bottom of the regeneration tower (1) is connected to the inlet of the main body of the reboiler (2) through an eighth circulation pump (18), and the top of the regeneration tower (1) is connected to the inlet of the regeneration gas cooler (4); The outlet of the main body of the reboiler (2) is communicated with the first return port at the bottom of the regeneration tower (1); the superheated steam pipeline (6) is communicated with the inlet of the heating part of the reboiler (2) through the desuperheater (3), and a first circulation pump (11) is provided on the superheated steam pipeline (6); the outlet of the heating part of the reboiler (2) is communicated with the inlet of the heating part of the regeneration gas heat exchanger (5) through the second circulation pump (12), and the outlet of the heating part of the regeneration gas heat exchanger (5) is used to communicate with the recovery pipeline; The liquid outlet of the regeneration gas cooler (4) is connected to the inlet of the main body of the regeneration gas heat exchanger (5), and the outlet of the main body of the regeneration gas heat exchanger (5) is connected to the top of the regeneration tower (1) through a third circulation pump (13); the gas outlet of the regeneration gas cooler (4) is used to communicate with the carbon dioxide gas processing device.

2. The carbon dioxide regeneration system according to claim 1, characterized in that: The temperature reducing and pressure reducing device (3) is provided with a first atomizing nozzle, and the first atomizing nozzle is connected to the heating part of the reboiler (2) through a fourth circulation pump (14).

3. The carbon dioxide regeneration system according to claim 2, characterized in that: The carbon dioxide regeneration system further comprises a flash tank (7), a booster pump (19) and a compressor (8); the inlet of the flash tank (7) is connected to the lean liquid outlet at the bottom of the regeneration tower (1) via the booster pump (19); the outlet of the flash tank (7) is connected to the inlet of the compressor (8); the outlet of the compressor (8) is connected to a second return port at the bottom of the regeneration tower (1); the second return port is located above the liquid level of the absorbent lean liquid in the regeneration tower (1).

4. The carbon dioxide regeneration system according to claim 3, characterized in that: A second atomizing nozzle is provided at the inlet of the compressor (8), and the second atomizing nozzle is connected to the heating part of the reboiler (2) through a fifth circulation pump (15).

5. The carbon dioxide regeneration system according to claim 3, characterized in that: The carbon dioxide regeneration system also includes an absorption tower (9), wherein a rich liquid outlet at the bottom of the absorption tower (9) is connected to a rich liquid inlet at the top of the regeneration tower (1) via a sixth circulation pump (16), and a lean liquid inlet at the top of the absorption tower (9) is connected to a lean liquid outlet at the bottom of the regeneration tower (1) via a seventh circulation pump (17), a flue gas outlet is provided at the top of the absorption tower (9), and a flue gas inlet is provided at the bottom of the absorption tower (9).

6. The carbon dioxide regeneration system according to claim 5, characterized in that: The lean liquid inlet at the top of the absorption tower (9) is connected to the liquid outlet of the regeneration gas cooler (4) through the main body of the regeneration gas heat exchanger (5); And / or, the carbon dioxide regeneration system also includes a lean-rich liquid heat exchanger (10), the rich liquid outlet at the bottom of the absorption tower (9) is connected to the rich liquid inlet at the top of the regeneration tower (1) through the rich liquid conveying part of the lean-rich liquid heat exchanger (10), and the lean liquid inlet at the top of the absorption tower (9) is connected to the lean liquid outlet at the bottom of the regeneration tower (1) through the lean liquid conveying part of the lean-rich liquid heat exchanger (10).

7. A method for regenerating carbon dioxide, characterized in that: include: The absorbent rich liquid is heated by the first heating steam, so that the absorbent rich liquid precipitates carbon dioxide gas and is converted into the absorbent lean liquid; at the same time, the superheated steam that has been reduced in temperature and pressure to a preset temperature and a preset pressure is used to heat a portion of the absorbent lean liquid, so that the absorbent lean liquid generates the first heating steam that heats the absorbent rich liquid; and the superheated steam forms steam condensed water with a preset temperature after heat exchange with the absorbent lean liquid; Cooling the carbon dioxide gas so that the water vapor mixed in the carbon dioxide gas is cooled into regeneration gas condensed water and separated from the carbon dioxide gas; exchanging heat between the steam condensed water and the regeneration gas condensed water to increase the temperature of the regeneration gas condensed water; The condensed water of the regeneration gas after the temperature is increased is returned to the first heating steam.

8. The carbon dioxide regeneration method according to claim 7, characterized in that: The carbon dioxide regeneration method further comprises: flashing another portion of the absorbent lean liquid to form absorbent lean liquid vapor; atomizing a portion of the steam condensate and further spraying the atomized water into the absorbent lean liquid steam to form a first mixed gas; compressing the first mixed gas to form second heating steam; The second heating steam is allowed to enter the second heating steam and heat the absorbent rich liquid.

9. The carbon dioxide regeneration method according to claim 8, characterized in that: The carbon dioxide regeneration method further comprises: spraying another portion of the steam condensate that has been atomized into the superheated steam to form a second mixed gas; reducing the temperature and pressure of the second mixed gas to form third heating steam with a preset temperature and a preset pressure; The third heating steam is used to heat a portion of the absorbent lean liquid, and the third heating steam that has completed the heat exchange is formed into the steam condensed water.

10. The carbon dioxide regeneration method according to claim 7, characterized in that: The carbon dioxide regeneration method is carried out using the carbon dioxide regeneration system according to any one of claims 1 to 6.

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