Membrane separation method-pressure swing adsorption-humidity swing adsorption coupled carbon capture system

Abstract

The utility model provides a membrane separation method-pressure swing adsorption-humidity swing adsorption coupled carbon capture system which comprises a membrane separation unit, a residual pressure recovery unit, a pressure swing adsorption unit, a humidity swing adsorption unit and a carbon dioxide purification and liquefaction unit, the pressure swing adsorption unit is a pressure swing adsorption tower group; flue gas enters from an inlet of a membrane separator, a permeation side outlet of the membrane separator is sequentially connected to a vacuum pump, a gas buffer tank I, a compressor, a heat exchanger and a compression end of an excess pressure recycling machine, and an outlet of the compression end of the excess pressure recycling machine is connected to a gas inlet of a pressure swing adsorption tower group; a CO2 product gas outlet of the pressure swing adsorption tower group is connected to the carbon dioxide purification and liquefaction unit; an interception side outlet of the membrane separator is sequentially connected to the heat exchanger and an expansion end of the residual pressure recycling machine, and an outlet of the expansion end of the residual pressure recycling machine is connected to a tail gas inlet of the humidifying adsorption unit. The carbon capture system provided by the utility model efficiently captures CO2, realizes recovery of pressure energy in the system, and reduces operation energy consumption.

Description

Technical Field

[0001] The utility model relates to the technical field of carbon capture, in particular to a membrane separation method-pressure swing adsorption-humidity swing adsorption coupled carbon capture system. Background Art

[0002] Chinese patent CN115212695A proposes a carbon dioxide capture system based on ionic liquid absorbent with membrane structure pretreatment. The system removes solid impurities in flue gas through a membrane pretreatment device, ensuring that the absorbent can operate stably for a long time while initially increasing the carbon dioxide concentration. The lean and rich liquid heat exchanger between the capture tower and the desorption tower uses the heat of the high-temperature lean liquid flowing out of the desorption tower to preheat the low-temperature rich liquid, thereby reducing the desorption energy consumption. The CO2 capture method mentioned in this method is mainly based on chemical absorption, combined with membrane separation pretreatment. Although it improves the problems of secondary pollution of the single chemical absorption method and low product concentration of the single membrane separation method, in the flue gas CO2 capture process, the regeneration energy consumption is still high, and there is still the problem of chemical waste liquid, which limits the large-scale CO2 capture application of this method.

[0003] Chinese patent CN115448313A discloses a method and device for separating and recovering industrial carbon dioxide from steel plant gas. Specifically, a combination of pressure swing adsorption of carbon dioxide for initial separation in the first stage, combined with low-temperature liquefaction and distillation of carbon dioxide for final separation in the second stage, and residual pressure utilization in the third stage can provide gaseous and liquid carbon dioxide products at the same time. The CO2 capture method mentioned in this method is mainly based on pressure swing adsorption. In the CO2 capture process of low CO2 partial pressure flue gas, under certain energy consumption constraints, the CO2 removal rate may be low, which is not conducive to the actual treatment of low CO2 partial pressure flue gas such as coal-fired power plants. Utility Model Content

[0004] In order to overcome the above-mentioned technical problems, the utility model provides a carbon capture system of membrane separation-pressure swing adsorption-humidity swing adsorption coupling, which can efficiently capture CO2, remove carbon dioxide in low-concentration flue gas, and realize pressure energy recovery in the system, thereby reducing operating energy consumption.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] The utility model provides a membrane separation method-pressure swing adsorption-humidity swing adsorption coupled carbon capture system, the carbon capture system comprises a membrane separation unit, a residual pressure recovery unit, a pressure swing adsorption unit, a humidity swing adsorption unit and a carbon dioxide purification and liquefaction unit;

[0007] Wherein, the membrane separation unit is a membrane separator, the residual pressure recovery unit is a residual pressure recovery machine, the residual pressure recovery machine includes a compression end, an intermediate and an expansion end connected in sequence, the pressure swing adsorption unit is a pressure swing adsorption tower group, the wet adsorption unit includes a wet adsorption device, a circulating water tank and a gas-liquid separator, wherein the wet adsorption device is provided with a tail gas inlet, a liquid phase recycling port, an adsorbed gas outlet, an emptying port, a circulating water inlet and a spray water outlet, the spray water outlet is connected to the inlet of the circulating water tank, the outlet of the circulating water tank is connected to the circulating water inlet, the adsorbed gas outlet is connected to the inlet of the gas-liquid separator, and the gas phase outlet of the gas-liquid separator is connected to the gas buffer tank I;

[0008] The flue gas containing CO2 enters the carbon capture system from the inlet of the membrane separator, and the outlet of the permeate side of the membrane separator is connected to the vacuum pump, the gas buffer tank I, the compressor, the heat exchanger and the compression end of the residual pressure recovery machine in sequence, and the outlet of the compression end of the residual pressure recovery machine is connected to the gas inlet of the pressure swing adsorption tower group, and the CO2 product gas outlet of the pressure swing adsorption tower group is connected to the carbon dioxide purification and liquefaction unit;

[0009] The retentate side outlet of the membrane separator is connected to the heat exchanger and the expansion end of the residual pressure recovery machine in sequence, and the outlet of the expansion end of the residual pressure recovery machine is connected to the tail gas inlet of the variable humidity adsorption unit.

[0010] In the membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system provided by the utility model, a gas buffer tank II is also arranged in front of the membrane separator, and the flue gas containing CO2 enters the membrane separator after being buffered by the gas buffer tank II.

[0011] In the membrane separation method-pressure swing adsorption-humidity swing adsorption coupled carbon capture system provided by the utility model, the pressure swing adsorption tower group is composed of two parallel pressure swing adsorption towers;

[0012] The bottom of the pressure swing adsorption tower is provided with a gas inlet, a pressure swing adsorption tail gas outlet and a CO2 product gas outlet arranged at the top, and the pressure swing adsorption tail gas outlet is connected to the tail gas inlet of the humidity swing adsorption device.

[0013] In the membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system provided by the utility model, the pressure swing adsorption tower is selected from a fixed bed adsorption tower.

[0014] In the membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system provided by the utility model, a vacuum pump and a compressor are sequentially connected between the pressure swing adsorption tower group and the carbon dioxide purification and liquefaction unit.

[0015] In the membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system provided by the utility model, the liquid phase recycling port of the humidity swing adsorption device is connected to the liquid phase outlet of the gas-liquid separator through a pipeline.

[0016] In the membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system provided by the utility model, a vacuum pump is further provided between the adsorbed gas outlet on the humidity swing adsorption device and the gas-liquid separator.

[0017] In the membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system provided by the utility model, a dehumidifier is arranged between the gas-liquid separator and the gas buffer tank I.

[0018] In the membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system provided by the utility model, a heat exchanger is connected between the spray water outlet and the circulating water tank.

[0019] In the membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system provided by the utility model, a circulation pump is arranged between the outlet of the circulation water tank and the circulation water inlet of the humidity swing adsorption device.

[0020] The above technical solution has the following technical effects:

[0021] The carbon capture system provided by the utility model couples three carbon capture technologies, effectively making up for the defects of low purity of single membrane product, low CO2 capture rate of single adsorption method, few application scenarios of single variable humidity adsorption method, and high regeneration energy consumption of single absorption method, and synergistically exerts the advantages of membrane separation (high permeability), pressure swing adsorption (high selectivity) and variable humidity adsorption (high sensitivity), and has good capture performance for low concentration CO2.

[0022] At the same time, the carbon capture system provided by the utility model cleverly uses the residual pressure recovery machine to arrange the material flow between the membrane assembly and the adsorption tower, which not only reduces the energy consumption of the system, but also reduces the tail gas temperature, which is conducive to further improving the capture rate of the variable humidity adsorption device. The capture system of the utility model can achieve the carbon capture goal of high capture rate and low energy consumption for low CO2 volume fraction scenarios, and provides a new and efficient carbon capture technology and new ideas. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 , a specific implementation of the carbon capture system provided by the utility model;

[0024] Figure 2 , the carbon capture system used in the comparative example provided by the present invention;

[0025] Among them, 1. Gas buffer tank II, 2. Membrane separator, 3. Vacuum pump, 4. Gas buffer tank I, 5. Compressor, 6. Heat exchanger, 7. Residual pressure recovery machine, 8. Fixed bed adsorption tower, 9. Variable humidity adsorption device, 10. Circulating water tank, 11. Circulating pump, 12. Gas-liquid separator, 13. Dehumidifier, 14. Carbon dioxide purification and liquefaction unit. DETAILED DESCRIPTION

[0026] In order to better understand the present invention, the following is an explanation in conjunction with the specific implementation methods of the present invention.

[0027] The utility model provides a membrane separation method-pressure swing adsorption-humidity swing adsorption coupled carbon capture system, such as Figure 1 As shown, the carbon capture system includes a membrane separation unit, a residual pressure recovery unit, a pressure swing adsorption unit, a wet swing adsorption unit and a carbon dioxide purification and liquefaction unit 14;

[0028] The membrane separation unit is specifically a membrane separator 2, the residual pressure recovery unit is specifically a residual pressure recovery machine 7, the residual pressure recovery machine 7 includes a compression end, an intermediate and an expansion end connected in sequence, the pressure swing adsorption unit is specifically a pressure swing adsorption tower group, and the wet adsorption unit includes a wet adsorption device, a circulating water tank 10 and a gas-liquid separator 12, wherein the wet adsorption device is provided with a tail gas inlet, a liquid phase recycling port, an adsorbed gas outlet, an emptying port, a circulating water inlet and a spray water outlet, the spray water outlet is connected to the inlet of the circulating water tank 10, the outlet of the circulating water tank 10 is connected to the circulating water inlet, the adsorbed gas outlet is connected to the inlet of the gas-liquid separator 12, and the gas phase outlet of the gas-liquid separator 12 is connected to the gas buffer tank Ⅰ4;

[0029] Flue gas containing CO2 enters the carbon capture system provided by the utility model through the gas inlet of the membrane separator 2, and the outlet of the permeation side (i.e., the product gas side) of the membrane separator 2 is sequentially connected to the vacuum pump 3, the gas buffer tank I4, the compressor 5, the heat exchanger 6, and the compression end of the residual pressure recovery machine 7, and the outlet of the compression end of the residual pressure recovery machine 7 is connected to the gas inlet of the pressure swing adsorption tower group, and the CO2 product gas outlet of the pressure swing adsorption tower group is connected to the carbon dioxide purification and liquefaction unit 14;

[0030] The retentate side outlet of the membrane separator 2 is connected to the heat exchanger 6 and the expansion end of the residual pressure recovery machine 7 in sequence, and the outlet of the expansion end of the residual pressure recovery machine 7 is connected to the tail gas inlet of the humidification adsorption unit.

[0031] In some specific embodiments, the air inlet pressure of the membrane separator 2 mentioned in the utility model is 0.1 MPaG, and the product gas side is evacuated by a vacuum pump 3, and the pressure is -0.08 MPaG. The air inlet flow rate of the membrane separator 2 is 1000 Nm 3 / h, the volume content of CO2 is 15%, and the inlet temperature is 30° C. In some more specific embodiments, the gas separation membrane equipped in the membrane separator 2 concentrates the CO2 flue gas with a volume content of 15% CO2 to a CO2 primary concentrated gas with a volume content of 50% CO2 to enter the pressure swing adsorption unit.

[0032] The residual pressure recovery machine 7 used in the carbon capture system provided by the utility model can also be called a residual pressure recovery refrigerator, and can use the residual pressure recovery device that can achieve the corresponding effect in the art, such as but not limited to the residual pressure recovery device disclosed in patent document CN202610241U. In some specific embodiments, the residual pressure recovery machine 7 is an integrated structure including a compression end, an intermediate body and an expansion end connected in sequence, the main shaft is installed in the intermediate body and passes through the compression end and the expansion end, and the pressure energy in the exhaust gas is converted into mechanical energy through the expansion of the exhaust gas at the expansion end and working outward, and the mechanical energy is used to compress the gas at the compression end to increase its pressure, thereby effectively recovering and converting the available energy in the exhaust gas, which has significant economic and social benefits.

[0033] Specifically, in the present invention, the tail gas on the interception side of the membrane separator 2 is introduced into the expansion end of the residual pressure recovery machine 7 to expand and perform work externally, converting the pressure energy in the tail gas on the membrane interception side into mechanical energy, and using the obtained mechanical energy to compress the flue gas to be adsorbed introduced into the compression end of the residual pressure recovery machine 7, so that the flue gas to be adsorbed is pressurized; the tail gas on the membrane interception side enters the residual pressure recovery machine 7 and is greatly cooled during the expansion process, and the cooled tail gas on the membrane interception side enters the humidification adsorption device 9. Through the recycling of the residual pressure recovery machine 7, the power requirement for pressurizing the flue gas to be adsorbed can be reduced under the premise of reasonable design of the turbine blades.

[0034] In some specific embodiments, a gas buffer tank II 1 is further provided in front of the membrane separator 2, and the flue gas containing CO 2 is purified and buffered in the gas buffer tank II 1 before entering the membrane separator 2 for membrane separation.

[0035] The pressure swing adsorption tower group in the carbon capture system provided by the present invention is composed of two parallel pressure swing adsorption towers; the fixed bed adsorption tower 8 is provided with a gas inlet, a pressure swing adsorption tail gas outlet and a CO2 product gas outlet at the top at the bottom, and the pressure swing adsorption tail gas outlet is connected to the tail gas inlet of the wet variable adsorption device 9. In some specific embodiments, the pressure swing adsorption tower is selected from the fixed bed adsorption tower 8.

[0036] In some specific embodiments, the fixed bed adsorption tower 8 includes a gas inlet, a pressure swing adsorption tail gas outlet and a CO2 product gas outlet. Multiple pressure swing adsorption towers can be connected in parallel and switched according to the adsorption cycle of "adsorption-pressure equalization-regeneration" to achieve continuous operation. The CO2 primary concentrated gas from the membrane separation unit and the CO2 concentrated gas from the variable humidity adsorption unit enter the pressure swing adsorption unit. In some specific embodiments, the CO2 volume content is 50% and the inlet pressure is 0.1-0.2MPaG. The adsorbent loaded in the fixed bed adsorption tower 8 further concentrates the gas with a CO2 volume content of 50% from the membrane separation unit and the variable humidity adsorption unit to a CO2 product gas with a CO2 purity of 95%.

[0037] A vacuum pump 3 and a compressor 5 are connected in sequence between the pressure swing adsorption tower group and the carbon dioxide purification and liquefaction unit 14 to extract the CO2 product gas adsorbed by the pressure swing adsorption tower to the carbon dioxide purification and liquefaction unit 14, and the liquid outlet of the purification and liquefaction unit is connected to the outside.

[0038] In the carbon capture system provided by the utility model, the exhaust gas of the pressure swing adsorption unit and the exhaust gas of the membrane separation unit enter the humidification adsorption device 9 together. The humidification adsorbent in the humidification adsorption device 9 adsorbs low concentration CO2 in the exhaust gas when it is dry. The water in the circulating water tank 10 enters the humidification adsorption device 9 through the circulating pump 11. After the water mist is sprayed out from the top of the humidification adsorption device 9, the humidification adsorbent releases CO2 concentrated gas with a CO2 volume content of 50%. The vacuum pump 3 extracts it and separates it through the gas-liquid separator 12 and then passes it into the gas buffer tank Ⅰ4. The humidification adsorption exhaust gas treated by the humidification adsorption device 9 is directly discharged from the exhaust port.

[0039] In some specific embodiments, a vacuum pump 3 is further provided between the adsorbed gas outlet on the variable humidity adsorption device 9 and the gas-liquid separator 12 to draw the adsorbed gas obtained by the variable humidity adsorption device 9 into the gas-liquid separator 12 for gas-liquid separation.

[0040] In some specific embodiments, the liquid phase recycling port of the variable humidity adsorption device 9 is connected to the liquid phase outlet of the gas-liquid separator 12 through a pipeline, so that the liquid phase after gas-liquid separation is continuously recycled to the variable humidity adsorption device 9 .

[0041] In some specific embodiments, a dehumidifier 13 is provided between the gas-liquid separator 12 and the gas buffer tank I4 to dry the CO2 released from the humidified adsorbent after being sprayed with water mist in the humidified adsorption device 9.

[0042] In some specific implementations, a heat exchanger 6 is connected between the variable humidity adsorption device 9 and the circulating water tank 10 , and a circulating pump 11 is provided between the outlet of the circulating water tank 10 and the circulating water inlet on the variable humidity adsorption device 9 .

[0043] Example

[0044] The following uses Figure 1 The membrane separation-pressure swing adsorption-wet swing adsorption coupled carbon capture system shown is used to capture carbon from flue gas with a CO2 concentration of 15%;

[0045] The air inlet pressure at the inlet of membrane separator 2 is 0.1MPaG, and the product gas side is evacuated by vacuum pump 3, and the pressure is -0.08MPaG. The air inlet flow rate of membrane separator 2 is 1000Nm 3 / h, CO2 volume content is 15%, and the inlet temperature is 30°C. The gas separation membrane installed in the membrane separator 2 concentrates the CO2 volume content from 15% CO2 flue gas to 50% CO2 primary concentrated gas, and then is buffered by the gas buffer tank Ⅰ4, and enters the compression end of the residual pressure recovery machine 7 after heat exchange in the heat exchanger 6, and the CO2 concentrated gas enters the fixed bed adsorption tower 8.

[0046] The volume content of CO2 at the gas inlet of the fixed bed adsorption tower 8 is 50%, and the inlet pressure is 0.1 MPaG. The adsorbent loaded in the fixed bed adsorption tower 8 further concentrates the gas with a volume content of 50% CO2 from the membrane separator 2 and the variable humidity adsorption device 9 into a CO2 product gas with a CO2 purity of 95%.

[0047] The tail gas from the fixed bed adsorption tower 8 and the tail gas from the membrane separator 2 enter the humidifying adsorption device 9 together. The humidifying adsorbent absorbs low concentration CO2 in the tail gas when it is dry. The circulating water enters the humidifying adsorption device 9 through the circulating pump 11. After the spray water mist on the top of the humidifying adsorption device 9 is sprayed out, the humidifying adsorbent releases CO2 concentrated gas with a CO2 volume content of 50%. The vacuum pump 3 extracts and dehumidifies it and then passes it into the gas buffer tank 4. After being pressurized, it circulates into the fixed bed adsorption tower 8 for capture. The treated humidifying adsorption tail gas is directly discharged.

[0048] Comparative Example

[0049] Use Figure 2 The carbon capture system shown captures carbon from flue gas with a CO2 concentration of 15%; the difference between this comparative example and the system of Example 1 is that no humidification adsorption unit is provided, and the tail gas of the membrane separation unit and the pressure swing adsorption unit is not returned to the pressure swing adsorption tower for reflux capture, but is directly discharged.

[0050] The CO2 capture rate in the embodiments and comparative examples was determined according to the following method: CO2 capture rate = volume flow rate of CO2 in the product gas of the pressure swing adsorption unit / volume flow rate of CO2 in the inlet gas of the membrane separation unit;

[0051] Among them, the volume flow rate of CO2 = the total volume flow rate of the mixed gas × the volume content of CO2 in the mixed gas.

[0052] After the system has been running for a period of time, the CO2 capture rate in Example 1 is 94.33%, and the CO2 capture rate in Comparative Example 1 is 80.72%.

[0053] From the capture rate results, it can be seen that the carbon capture system of Example 1 using the membrane separation-pressure swing adsorption-humidity swing adsorption coupling process can efficiently capture CO2, remove carbon dioxide from low-CO2 flue gas, and realize pressure energy recovery in the system, thereby reducing operating energy consumption.

[0054] In Comparative Example 1, the tail gas of the membrane separation unit and the tail gas of the pressure swing adsorption unit are directly discharged, resulting in a small amount of CO2 remaining in the tail gas of the membrane separation unit and the pressure swing adsorption unit not being captured again, so the overall CO2 capture capacity of the system is reduced. In addition, due to the discharge of the tail gas of the membrane separation unit and the pressure swing adsorption unit, the product gas finally obtained by the comparative example system is 127.45Nm 3 / h, 95% CO2. Compared with 148.94Nm in Example 1 3 / h, 95% CO2 product gas, and the final CO2 product amount was reduced by 14.43%.

Claims

1. A membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system, characterized in that: The carbon capture system includes a membrane separation unit, a residual pressure recovery unit, a pressure swing adsorption unit, a wet swing adsorption unit and a carbon dioxide purification and liquefaction unit; Wherein, the membrane separation unit is a membrane separator, the residual pressure recovery unit is a residual pressure recovery machine, the residual pressure recovery machine includes a compression end, an intermediate and an expansion end connected in sequence, the pressure swing adsorption unit is a pressure swing adsorption tower group, the wet adsorption unit includes a wet adsorption device, a circulating water tank and a gas-liquid separator, wherein the wet adsorption device is provided with a tail gas inlet, a liquid phase recycling port, an adsorbed gas outlet, an emptying port, a circulating water inlet and a spray water outlet, the spray water outlet is connected to the inlet of the circulating water tank, the outlet of the circulating water tank is connected to the circulating water inlet, the adsorbed gas outlet is connected to the inlet of the gas-liquid separator, and the gas phase outlet of the gas-liquid separator is connected to the gas buffer tank I; The flue gas containing CO2 enters the carbon capture system from the inlet of the membrane separator, and the outlet of the permeate side of the membrane separator is connected to the vacuum pump, the gas buffer tank I, the compressor, the heat exchanger and the compression end of the residual pressure recovery machine in sequence, and the outlet of the compression end of the residual pressure recovery machine is connected to the gas inlet of the pressure swing adsorption tower group, and the CO2 product gas outlet of the pressure swing adsorption tower group is connected to the carbon dioxide purification and liquefaction unit; The retentate side outlet of the membrane separator is connected to the heat exchanger and the expansion end of the residual pressure recovery machine in sequence, and the outlet of the expansion end of the residual pressure recovery machine is connected to the tail gas inlet of the variable humidity adsorption unit.

2. The membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system according to claim 1, characterized in that: A gas buffer tank II is also arranged in front of the membrane separator, and the flue gas containing CO2 enters the membrane separator after being buffered by the gas buffer tank II.

3. The membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system according to claim 2, characterized in that: The pressure swing adsorption tower group is composed of two parallel pressure swing adsorption towers; The bottom of the pressure swing adsorption tower is provided with a gas inlet, a pressure swing adsorption tail gas outlet and a CO2 product gas outlet arranged at the top, and the pressure swing adsorption tail gas outlet is connected to the tail gas inlet of the humidity swing adsorption device.

4. The membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system according to claim 3, characterized in that: The pressure swing adsorption tower is selected from a fixed bed adsorption tower.

5. The membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system according to claim 4, characterized in that: A vacuum pump and a compressor are connected in sequence between the pressure swing adsorption tower group and the carbon dioxide purification and liquefaction unit.

6. The membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system according to claim 5, characterized in that: The liquid phase recycling port of the variable humidity adsorption device is connected to the liquid phase outlet of the gas-liquid separator through a pipeline.

7. The membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system according to claim 6, characterized in that: A vacuum pump is also provided between the adsorbed gas outlet on the variable humidity adsorption device and the gas-liquid separator.

8. The membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system according to claim 7, characterized in that: A dehumidifier is arranged between the gas-liquid separator and the gas buffer tank I.

9. The membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system according to any one of claims 1 to 8, characterized in that: A heat exchanger is connected between the spray water outlet and the circulating water tank.

10. The membrane separation-pressure swing adsorption-humidity swing adsorption coupled carbon capture system according to claim 9, characterized in that: A circulation pump is arranged between the outlet of the circulation water tank and the circulation water inlet of the variable humidity adsorption device.

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