Double-tube alternating type flue gas carbon capture device and method behind desulfurization and denitrification device

Abstract

The invention discloses a double-tube alternating type flue gas carbon capture device and method behind a desulfurization and denitrification device, and belongs to the field of flue gas purification. The low-temperature flue gas pipeline I penetrates through the reaction chamber I, and the low-temperature flue gas pipeline I is provided with an air inlet valve I and an exhaust valve I on the two sides of the reaction chamber I respectively; the low-temperature flue gas pipeline II penetrates through the reaction chamber II, and the low-temperature flue gas pipeline II is provided with an air inlet valve II and an exhaust valve II on the two sides of the reaction chamber II respectively; the gas inlet end of the low-temperature flue gas pipeline II is communicated with the gas inlet end of the low-temperature flue gas pipeline I; and the carbon dioxide collecting chamber is communicated with the low-temperature flue gas pipeline I and the low-temperature flue gas pipeline II through communicating pipes. The device becomes a plug-and-play modular unit, can be embedded between a desulfurization and denitrification system and a chimney, does not interfere with the original flue gas flow, and does not need to transform core equipment such as a boiler and a desulfurization tower. The desorption requirement can be met by directly utilizing low-temperature flue gas waste heat in a power plant, extra energy consumption is saved, and a heating system is simplified. The adsorption efficiency is improved. And residual carbon dioxide in the reaction chamber is reduced.

Description

Technical Field

[0001] This invention relates to a dual-tube alternating flue gas carbon capture device and method after a desulfurization and denitrification device, belonging to the field of flue gas purification. Background Technology

[0002] As a major source of carbon emissions, reducing carbon dioxide emissions from flue gas at thermal power plants has become a key task for industry upgrading. Currently, mainstream flue gas treatment processes at thermal power plants focus solely on desulfurization and denitrification, removing pollutants such as sulfur and nitrates through equipment such as desulfurization towers and SCR / SNCR denitrification reactors. While this can meet conventional environmental protection requirements, the flue gas after desulfurization and denitrification still contains a large amount of carbon dioxide, and direct emissions will exacerbate the greenhouse effect. Furthermore, existing power plant flue gas systems generally lack targeted end-of-pipe carbon capture modules.

[0003] Current carbon capture technologies in the industry have significant shortcomings: pre-combustion or in-combustion capture technologies require large-scale modifications to core equipment such as power plant boilers and burners, resulting in high initial investment costs, long modification cycles, and disruption to the normal and stable operation of the power plant. Existing end-of-pipe carbon capture technologies mostly employ a single-tube intermittent design, which inherently suffers from the inability to synchronize adsorption and desorption processes, leading to low carbon capture efficiency. Furthermore, the heating and cooling systems of some technologies are complex and energy-intensive, making them difficult to adapt to the flow parameters and temperature characteristics of flue gas after desulfurization and denitrification. Simultaneously, traditional end-of-pipe carbon capture devices have deficiencies in desorption power supply methods and continuous operation stability.

[0004] When applied to specific scenarios such as thermal power plants with high flow rates and continuous stable operation, the few existing dual-chamber alternating carbon capture technologies have revealed more prominent adaptability drawbacks: they rely on active power equipment such as vacuum pumps to provide desorption power, resulting in increased system energy consumption and maintenance workload; the heat exchange efficiency is limited, directly affecting the improvement of the desorption rate; the overall system structure is complex and occupies a large area, which is not conducive to the compact transformation of existing power plants and the integration and adaptation of the original flue gas system.

[0005] Currently, there is no mature technical solution that can achieve efficient desorption without complex power equipment and by relying on temperature difference and preset pressure. Therefore, improvements have been made to it. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned problems in the background art and to provide a dual-pipe alternating flue gas carbon capture device and method after a desulfurization and denitrification device.

[0007] The present invention achieves the above objectives by adopting the following technical solution: A dual-pipe alternating flue gas carbon capture device following a desulfurization and denitrification unit includes a low-temperature flue gas duct I, a low-temperature flue gas duct II, a reaction chamber I, a reaction chamber II, a high-temperature flue gas duct, and a carbon dioxide collection chamber. The low-temperature flue gas duct I passes through the reaction chamber I, and an inlet valve I and an exhaust valve I are respectively located on both sides of the reaction chamber I. The low-temperature flue gas duct II passes through the reaction chamber II, and an inlet valve II and an exhaust valve II are respectively located on both sides of the reaction chamber II. The inlet end of the low-temperature flue gas duct II is connected to the inlet end of the low-temperature flue gas duct I. The carbon dioxide collection chamber is connected to the low-temperature flue gas ducts I and II via a connecting pipe.

[0008] Preferably, the connecting pipe is provided in two sets. One set connects the inlet ends of low-temperature flue gas pipe I and low-temperature flue gas pipe II to the carbon dioxide collection chamber, and control valve I and control valve II are respectively provided on the connecting pipe. The other set of connecting pipes connects the exhaust ends of low-temperature flue gas pipe I and low-temperature flue gas pipe II to the carbon dioxide collection chamber, and control valve III and control valve IV are respectively provided on the connecting pipe.

[0009] Preferably, reaction chamber I and reaction chamber II are connected by a high-temperature flue gas duct; the high-temperature flue gas duct is equipped with valve I for controlling the flue gas entering reaction chamber I and valve II for controlling the flue gas entering reaction chamber II.

[0010] Preferably, the side of reaction chamber I is provided with flue gas outlet I, and the side of reaction chamber II is provided with flue gas outlet II.

[0011] Preferably, the side of the carbon dioxide collection chamber is also provided with a carbon dioxide discharge pipe; the carbon dioxide discharge pipe is provided with a one-way gas valve.

[0012] Preferably, a carbon dioxide adsorbent is provided in the low-temperature flue gas duct I and the low-temperature flue gas duct II located inside the reaction chamber I and the reaction chamber II.

[0013] Preferably, the high-temperature flue gas introduced into reaction chamber I and reaction chamber II through the high-temperature flue gas duct is discharged through flue gas outlet I and flue gas outlet II, respectively.

[0014] Preferably, the exhaust end of the low-temperature flue gas duct I is provided with exhaust port I; the exhaust end of the low-temperature flue gas duct II is provided with exhaust port II.

[0015] A method of using a dual-tube alternating flue gas carbon capture device following a desulfurization and denitrification unit, the method comprising the following steps: Step 1: Open the inlet valve I and guide the desulfurized and denitrified low-temperature flue gas from the inlet end of the low-temperature flue gas pipeline I to the position of the low-temperature flue gas pipeline I located in the reaction chamber I; Step 2: Close valve I and open valve II; guide the high-temperature flue gas after passing through the air preheater from the high-temperature flue gas duct to the space between the inner wall of reaction chamber II and low-temperature flue gas duct II to heat the low-temperature flue gas duct II; Step 3: Open control valves II and IV located between reaction chamber II and carbon dioxide collection chamber to form a circulation loop; Step 4: Carbon dioxide in the low-temperature flue gas is captured by carbon dioxide adsorbent in the low-temperature flue gas duct 1 located inside reaction chamber 1. After purification, the flue gas is discharged from exhaust port 1. High-temperature flue gas heats the low-temperature flue gas duct 2 located inside reaction chamber 2, causing its carbon dioxide adsorbent to desorb. The desorbed high-temperature carbon dioxide circulates naturally along the low-temperature flue gas duct 2 and the connecting pipe circulation loop under the drive of temperature difference, and gathers in the carbon dioxide collection chamber. Step 5: After running for the predetermined time, switch the opening and closing status of all relevant valves to switch reaction chamber I to desorption mode and reaction chamber II to adsorption mode. Step Six: Repeat steps one through five to achieve continuous carbon capture.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. The coupling of the shell-and-tube structure, direct heating and natural circulation makes this device a plug-and-play modular unit. It does not require complex power equipment and a large heat exchange system. The device can be embedded between the desulfurization and denitrification system and the chimney without interfering with the original flue gas flow and without requiring modification to core equipment such as boilers and desulfurization towers.

[0017] 2. The desorption requirements can be met by directly utilizing the waste heat from the low-temperature flue gas in the power plant, saving additional energy consumption and simplifying the heating system.

[0018] 3. Reaction chambers I and II are not connected to the low-temperature flue gas duct to avoid the impact of untreated flue gas on the performance of the carbon dioxide adsorbent and to improve adsorption efficiency.

[0019] 4. The carbon dioxide collected in the carbon dioxide collection chamber is driven by temperature difference to form a natural circulation with the carbon dioxide generated in the desorption reaction chamber in the pipeline. This circulation is used to remove the stagnant carbon dioxide gas in the reaction chamber and reduce the residual carbon dioxide in the reaction chamber. Attached Figure Description

[0020] Figure 1 This is a three-dimensional structural schematic diagram of a dual-tube alternating flue gas carbon capture device following a desulfurization and denitrification device according to the present invention. Figure 2 This is a three-dimensional structural diagram of a dual-tube alternating flue gas carbon capture device following a desulfurization and denitrification device according to the present invention, from another direction. Figure 3This is a cross-sectional view of reaction chamber I and reaction chamber II of a dual-tube alternating flue gas carbon capture device following a desulfurization and denitrification device according to the present invention. Figure 4 This is a schematic diagram of the working process of a dual-pipe alternating flue gas carbon capture device following a desulfurization and denitrification device according to the present invention. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] Specific implementation method one: as follows Figure 1-4 As shown, this embodiment describes a dual-pipe alternating flue gas carbon capture device after a desulfurization and denitrification unit, including a low-temperature flue gas pipe I1, a low-temperature flue gas pipe II23, a reaction chamber I6, a reaction chamber II7, a high-temperature flue gas pipe 2, and a carbon dioxide collection chamber 8; the low-temperature flue gas pipe I1 passes through the reaction chamber I6, and an inlet valve I11 and an exhaust valve I17 are respectively provided on both sides of the low-temperature flue gas pipe I1 located in the reaction chamber I6; the low-temperature flue gas pipe II23 passes through the reaction chamber II7, and an inlet valve II12 and an exhaust valve II18 are respectively provided on both sides of the low-temperature flue gas pipe II23 located in the reaction chamber II7; the inlet end of the low-temperature flue gas pipe II23 is connected to the inlet end of the low-temperature flue gas pipe I1; the carbon dioxide collection chamber 8 is connected to the low-temperature flue gas pipe I1 and the low-temperature flue gas pipe II23 through a connecting pipe 24. The inlet of low-temperature flue gas duct I1 is connected to the outlet of the power plant's desulfurization unit, while exhaust ports I3 and II4 are connected to the power plant's chimney and can be directly discharged into the atmosphere. High-temperature flue gas duct 2 is connected to the outlet of the air preheater. All ducts in this unit are connected via flanges, eliminating the need for modifications to existing equipment during operation.

[0023] The inlet ends of low-temperature flue gas duct I1 and low-temperature flue gas duct II23 are connected. Simultaneously, inlet valves I11 and II12 control the entry of low-temperature flue gas into either low-temperature flue gas duct I1 or low-temperature flue gas duct II23. A portion of low-temperature flue gas duct I1 is located inside reaction chamber I6, and a portion of low-temperature flue gas duct II23 is located inside reaction chamber II7. When high-temperature flue gas is introduced into reaction chamber I6 or reaction chamber II7, the temperature within reaction chamber I6 or reaction chamber II7 rises, and this temperature is further increased in low-temperature flue gas duct I1 or low-temperature flue gas duct II23, facilitating the desorption of the carbon dioxide adsorbent.

[0024] The connecting pipe 24 is provided in two sets. One set connects the inlet ends of the low-temperature flue gas pipe I1 and the low-temperature flue gas pipe II23 to the carbon dioxide collection chamber 8, and control valve I13 and control valve II14 are respectively provided on the connecting pipe 24. The other set of connecting pipes 24 connects the exhaust ends of the low-temperature flue gas pipe I1 and the low-temperature flue gas pipe II23 to the carbon dioxide collection chamber 8, and control valve III15 and control valve IV16 are respectively provided on the connecting pipe 24.

[0025] Open control valve I13 and control valve III15, and close control valve II14 and control valve IV16. At this time, the high-temperature flue gas circulates in the carbon dioxide collection chamber 8 and the low-temperature flue gas pipe I1 located in the reaction chamber I6, and is in a desorption state. The low-temperature flue gas pipe II23 inside the reaction chamber II7 is in an adsorption state.

[0026] Close control valve I13 and control valve III15, and open control valve II14 and control valve IV16. At this time, the high-temperature flue gas circulates in the carbon dioxide collection chamber 8 and the low-temperature flue gas pipe II23 located in the reaction chamber II7, and is in a desorption state. The low-temperature flue gas pipe I1 inside the reaction chamber I6 is in an adsorption state.

[0027] The reaction chambers I6 and II7 are connected by a high-temperature flue gas duct 2. The high-temperature flue gas duct 2 is equipped with valve I19 for controlling the flow of flue gas into reaction chamber I6 and valve II20 for controlling the flow of flue gas into reaction chamber II7. The flow direction of the high-temperature flue gas is controlled by valves I19 and II20 according to the operating states of reaction chambers I6 and II7, and is adapted to the operating states of reaction chambers I6 and II7.

[0028] The reaction chamber I6 has a flue gas outlet I9 on its side, and the reaction chamber II7 has a flue gas outlet II10 on its side. These are used to discharge high-temperature flue gas.

[0029] The carbon dioxide collection chamber 8 is also provided with a carbon dioxide discharge pipe 5 on its side; the carbon dioxide discharge pipe 5 is provided with a gas one-way valve 21.

[0030] Carbon dioxide adsorbent is installed in the low-temperature flue gas ducts I1 and II23 located inside the reaction chambers I6 and II7. The carbon dioxide adsorbent is fixed in the low-temperature flue gas ducts I1 and II23 by a sponge to prevent the carbon dioxide adsorbent from being carried out by the flue gas.

[0031] The high-temperature flue gas introduced into reaction chamber I6 and reaction chamber II7 through the high-temperature flue gas pipe 2 is discharged through flue gas outlet I9 and flue gas outlet II10, respectively.

[0032] The exhaust end of the low-temperature flue gas duct I1 is provided with exhaust port I3; the exhaust end of the low-temperature flue gas duct II23 is provided with exhaust port II4. When reaction chamber I6 is in the adsorption state (high-temperature flue gas is introduced into reaction chamber II7), exhaust valve I17 is open and exhaust valve II18 is closed. When reaction chamber II7 is in the adsorption state (high-temperature flue gas is introduced into reaction chamber I6), exhaust valve I17 is closed and exhaust valve II18 is open.

[0033] A method of using a dual-tube alternating flue gas carbon capture device following a desulfurization and denitrification unit, the method comprising the following steps: When using it for the first time, only open the intake valve I11, intake valve II12, exhaust valve I17, and exhaust valve II18 to ensure that reaction chamber I6 and reaction chamber II7 are in the adsorption state.

[0034] Step 1: When reaction chamber I6 adsorbs and reaction chamber II7 desorbs, open inlet valve I11 and exhaust valve I17, and close inlet valve II12 and exhaust valve II18. The desulfurized and denitrified low-temperature flue gas is led from the inlet end of low-temperature flue gas pipe I1 to the position of low-temperature flue gas pipe I1 located in reaction chamber I6, so that the carbon dioxide adsorbent in low-temperature flue gas pipe I1 adsorbs the carbon dioxide in the low-temperature flue gas. Step 2: Close valve I19 and open valve II20; guide the high-temperature flue gas after passing through the air preheater from the high-temperature flue gas pipe 2 to the space between the inner wall of the reaction chamber II7 and the low-temperature flue gas pipe II23, heat the low-temperature flue gas pipe II23, and raise the temperature of the carbon dioxide adsorbent inside it. After reaching the desorption temperature, the carbon dioxide adsorbed by the adsorbent is desorbed. At this time, the temperature of the reaction chamber II7 is consistent with the temperature of the high-temperature flue gas. Step 3: Open control valves II14 and IV16 located between reaction chamber II7 and carbon dioxide collection chamber 8, and close control valves I13 and III15 to form a circulation loop and prevent carbon dioxide in carbon dioxide collection chamber 8 from entering reaction chamber I6. Since the temperature of carbon dioxide collection chamber 8 is at room temperature and the temperature of reaction chamber II 7 is at high temperature, the gas expands and, under the action of the temperature difference, pushes the carbon dioxide gas to circulate in the loop formed by the pipeline where control valve II 14 is located, the pipeline where control valve IV 16 is located, and reaction chamber II 7, carrying out the stagnant carbon dioxide gas in reaction chamber 7. Step 4: Carbon dioxide in the low-temperature flue gas is captured by a carbon dioxide adsorbent in the low-temperature flue gas duct I1 located inside reaction chamber I6. After purification, the flue gas is discharged from exhaust port I3. Step 5: After running for the predetermined time, switch the opening and closing status of all relevant valves so that reaction chamber I6 switches to desorption mode and reaction chamber II7 switches to adsorption mode; When adsorption and desorption are complete, switch the operating states of reaction chamber I6 and reaction chamber II7. Reaction chamber I6 performs desorption, while reaction chamber II7 performs adsorption. Close inlet valve I11 and exhaust valve I17, preventing low-temperature flue gas from passing through reaction chamber I6. Open valve I19, allowing high-temperature flue gas to enter the outer layer of reaction chamber I6, heating the adsorbent in the low-temperature flue gas pipe I1 within reaction chamber I6. Once the desorption temperature is reached, the adsorbed carbon dioxide is desorbed. At this point, the temperature of reaction chamber I6 is consistent with the temperature of the high-temperature flue gas. Open control valves I13 and III15. Since the temperature in carbon dioxide collection chamber 8 is at room temperature while the temperature in reaction chamber I6 is high, the gas expands. Under the influence of the temperature difference, the carbon dioxide gas is propelled to circulate in the loop formed by the pipes containing control valve I13, control valve III15, and reaction chamber I6, carrying out the stagnant carbon dioxide gas in reaction chamber I6. Simultaneously, adsorption occurs in reaction chamber II7. Inlet valve II12 and exhaust valve II18 are opened, and low-temperature flue gas enters reaction chamber II7 through the inlet end of low-temperature flue gas pipe I1 and low-temperature flue gas pipe II23. There is an adsorbent fixed with sponge in reaction chamber II7, which adsorbs carbon dioxide in the low-temperature flue gas. Valve II20 is closed, so the high-temperature flue gas does not heat reaction chamber II7, and the temperature of reaction chamber II7 is consistent with the temperature of low-temperature flue gas. Control valves II14 and IV16 are closed, so carbon dioxide from carbon dioxide collection chamber 8 does not enter reaction chamber II7.

[0035] Step Six: Repeat steps one through five to achieve continuous carbon capture.

[0036] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0037] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A dual-tube alternating flue gas carbon capture device after a desulfurization and denitrification unit, characterized in that: It includes a low-temperature flue gas duct I (1), a low-temperature flue gas duct II (23), a reaction chamber I (6), a reaction chamber II (7), a high-temperature flue gas duct (2), and a carbon dioxide collection chamber (8); the low-temperature flue gas duct I (1) passes through the reaction chamber I (6), and the low-temperature flue gas duct I (1) is provided with an inlet valve I (11) and an exhaust valve I (17) on both sides of the reaction chamber I (6); the low-temperature flue gas duct II (23) passes through the reaction chamber II (7), and the low-temperature flue gas duct II (23) is provided with an inlet valve II (12) and an exhaust valve II (18) on both sides of the reaction chamber II (7); the inlet end of the low-temperature flue gas duct II (23) is connected to the inlet end of the low-temperature flue gas duct I (1); the carbon dioxide collection chamber (8) is connected to the low-temperature flue gas duct I (1) and the low-temperature flue gas duct II (23) through a connecting pipe (24).

2. The dual-tube alternating flue gas carbon capture device after the desulfurization and denitrification unit according to claim 1, characterized in that: The connecting pipe (24) is provided in two sets. One set connects the inlet end of the low-temperature flue gas pipe I (1) and the low-temperature flue gas pipe II (23) to the carbon dioxide collection chamber (8), and control valve I (13) and control valve II (14) are respectively provided on the connecting pipe (24); the other set of connecting pipes (24) connects the exhaust end of the low-temperature flue gas pipe I (1) and the low-temperature flue gas pipe II (23) to the carbon dioxide collection chamber (8), and control valve III (15) and control valve IV (16) are respectively provided on the connecting pipe (24).

3. The dual-tube alternating flue gas carbon capture device after the desulfurization and denitrification unit according to claim 1, characterized in that: The reaction chamber I (6) and reaction chamber II (7) are connected by a high-temperature flue gas pipe (2); the high-temperature flue gas pipe (2) is equipped with a valve I (19) for controlling the flue gas to enter the reaction chamber I (6) and a valve II (20) for controlling the flue gas to enter the reaction chamber II (7).

4. The dual-pipe alternating flue gas carbon capture device after the desulfurization and denitrification unit according to claim 3, characterized in that: The side of the reaction chamber I (6) is provided with a flue gas outlet I (9), and the side of the reaction chamber II (7) is provided with a flue gas outlet II (10).

5. The dual-tube alternating flue gas carbon capture device after the desulfurization and denitrification unit according to claim 1, characterized in that: The carbon dioxide collection chamber (8) is also provided with a carbon dioxide outlet pipe (5) on its side; a gas one-way valve (21) is provided on the carbon dioxide outlet pipe (5).

6. The dual-tube alternating flue gas carbon capture device after the desulfurization and denitrification unit according to claim 1, characterized in that: Carbon dioxide adsorbent is provided in the low-temperature flue gas duct I (1) and low-temperature flue gas duct II (23) located inside the reaction chamber I (6) and reaction chamber II (7).

7. The dual-tube alternating flue gas carbon capture device after the desulfurization and denitrification unit according to claim 4, characterized in that: The high-temperature flue gas introduced into reaction chamber I (6) and reaction chamber II (7) through the high-temperature flue gas pipe (2) is discharged through flue gas outlet I (9) and flue gas outlet II (10), respectively.

8. The dual-tube alternating flue gas carbon capture device after the desulfurization and denitrification unit according to claim 1, characterized in that: The exhaust end of the low-temperature flue gas duct I (1) is provided with exhaust port I (3); the exhaust end of the low-temperature flue gas duct II (23) is provided with exhaust port II (4).

9. The method of using the dual-pipe alternating flue gas carbon capture device after the desulfurization and denitrification unit according to claim 1, characterized in that: The method of use includes the following steps: Step 1: Open the inlet valve I (11) and guide the desulfurized and denitrified low-temperature flue gas from the inlet end of the low-temperature flue gas pipeline I (1) to the position of the low-temperature flue gas pipeline I (1) located in the reaction chamber I (6); Step 2: Close valve I (19) and open valve II (20); guide the high-temperature flue gas after passing through the air preheater from the high-temperature flue gas pipe (2) to the space between the inner wall of the reaction chamber II (7) and the low-temperature flue gas pipe II (23) to heat the low-temperature flue gas pipe II (23); Step 3: Open control valve II (14) and control valve IV (16) located between reaction chamber II (7) and carbon dioxide collection chamber (8) to form a circulation loop; Step 4: The carbon dioxide in the low-temperature flue gas is captured by the carbon dioxide adsorbent in the low-temperature flue gas pipe I (1) located inside the reaction chamber I (6), and the purified flue gas is discharged from the exhaust port I (3). Step 5: After running for the predetermined time, switch the opening and closing status of all relevant valves so that reaction chamber I (6) is switched to desorption mode and reaction chamber II (7) is switched to adsorption mode; Step Six: Repeat steps one through five to achieve continuous carbon capture.

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