A steam heat pump assisted direct air carbon capture system

Abstract

The application discloses a steam heat pump assisted direct air carbon capture system and belongs to the field of air direct carbon capture cycles, which comprises an air carbon capture unit, a waste heat recovery unit, a refrigerant circulation unit and a flash tank, wherein the air carbon capture unit comprises a plurality of reaction beds arranged in parallel, a gas supply device and an exhaust device communicated with the reaction beds, wherein the reaction bed is used for adsorption and desorption of air carbon capture; the waste heat recovery unit comprises a waste heat supply pipeline, an evaporator and a waste heat recovery pipeline communicated in sequence; the refrigerant circulation unit comprises a compressor, a condenser, an expansion valve, an evaporator, a gas-liquid separator and an ejector pump communicated in sequence and forming a circulation loop; the flash tank is communicated with the reaction bed and the condenser respectively. The application effectively recovers waste heat in the waste heat source by using the evaporator, fully utilizes low-quality energy and realizes the effect of energy saving and emission reduction.

Description

Technical Field

[0001] This invention belongs to the field of direct air carbon capture cycle, and particularly relates to a direct air carbon capture system assisted by a steam heat pump. Background Technology

[0002] The combustion of fossil fuels is causing a continuous increase in atmospheric carbon dioxide concentration, making the reduction of anthropogenic carbon dioxide emissions and mitigation of global warming a global consensus. Direct carbon dioxide capture from the atmosphere is one of the most effective negative emission technologies besides biocapture. It has advantages such as small footprint and flexible deployment, and possesses significant carbon reduction potential. However, high energy consumption and high capture costs severely restrict its application in society. Currently, approximately 80% of the energy consumed in continuous direct carbon dioxide capture systems is thermal energy; therefore, reducing this thermal energy consumption can effectively lower capture costs. Heat pump systems are highly efficient energy-saving systems that can effectively recover low-grade heat sources. Therefore, combining heat pump systems with continuous direct carbon dioxide capture systems to recover waste heat from industrial, chemical, and municipal wastewater treatment is an effective energy-saving measure.

[0003] Currently, continuous direct capture systems for carbon dioxide in the air are divided into high-temperature absorption capture systems and low-temperature adsorption capture systems. The desorption temperature of continuous direct capture systems for carbon dioxide in the air using solid amine-based adsorbents is relatively low, ranging from 80℃ to 120℃. However, the adsorption temperature of direct capture systems for carbon dioxide in the air is generally ambient temperature, and the dynamic transition from adsorption to desorption requires a significant temperature rise. Directly using a waste heat steam pump system to provide steam to meet the high temperatures required for desorption in continuous direct capture systems for carbon dioxide in the air presents problems such as a narrow system applicability (requiring high-temperature waste heat) and low coefficient of performance (COP).

[0004] Existing technologies combine conventional heat pumps with air carbon dioxide capture systems, where the heat pump system generates hot water to supply the air carbon dioxide capture system. For example, in the patent "A Dual-Heat-Source Heat Pump Type Direct Air Carbon Capture System," the hot water and the air carbon dioxide capture system do not directly contact each other. The capture material is heated by the hot water, and then extracted by a vacuum pump to capture carbon dioxide. This process is called temperature-switching vacuum adsorption, which places high demands on the vacuum pump and results in high energy consumption. Summary of the Invention

[0005] To solve the above problems, the present invention adopts the following technical solution:

[0006] A steam heat pump-assisted direct air carbon capture system includes:

[0007] An air carbon capture unit includes multiple reaction beds arranged in parallel and an air supply device and an exhaust device connected to the reaction beds, wherein the reaction beds are used for the adsorption and desorption of air carbon.

[0008] Waste heat recovery unit, the waste heat recovery unit includes a waste heat supply pipeline, an evaporator and a waste heat return pipeline connected in sequence;

[0009] A refrigerant circulation unit includes a compressor, a condenser, an expansion valve, an evaporator, a gas-liquid separator, and an ejector pump, which are connected in sequence to form a circulation loop. The gas-liquid separator is connected to the reaction bed, the condenser, a vacuum pump, and the ejector pump. The ejector pump transfers the refrigerant output from the gas-liquid separator and the evaporator to the compressor. The reaction bed delivers vaporized carbon dioxide gas to the gas-liquid separator. The gas-liquid separator separates water vapor and carbon dioxide gas. The water vapor is condensed and transferred to the condenser, and the carbon dioxide gas is transferred to the vacuum pump.

[0010] A flash tank is connected to the reaction bed and the condenser, respectively, and is used to supply steam and saturated water to the reaction bed.

[0011] Furthermore, when the reaction bed is in an adsorption state, air enters the reaction bed through the gas supply device, wherein carbon dioxide in the air is captured by the reaction bed, and gas without carbon dioxide flows out into the atmosphere through the exhaust device.

[0012] Furthermore, the compressor, condenser, expansion valve, evaporator, and ejector pump, which are connected in sequence to form a circulation loop, constitute the first refrigerant circulation loop. The condenser, gas-liquid separator, ejector pump, and compressor form the second refrigerant circulation loop. In this loop, the refrigerant absorbs the heat from the waste heat in the evaporator and the heat released by the condensation of water vapor in the gas-liquid separator. The two streams of refrigerant that have absorbed heat converge in the compressor. After compression and upgrading, they provide heat to the water flowing through the condenser, so that the water reaches the temperature required to generate steam after entering the flash tank.

[0013] Furthermore, when the reaction bed is in a desorption state, the flash tank generates steam and supplies steam and saturated water to the reaction bed to meet the desorption temperature. The steam carries away the carbon dioxide gas captured in the reaction bed. The mixture of steam and carbon dioxide is cooled in the gas-liquid separator to separate the carbon dioxide and condensed water. The carbon dioxide gas is collected by the vacuum pump, and the condensed water is discharged through the gas-liquid separator and merges with the saturated water discharged from the flash tank of the reaction bed into the condenser. After absorbing heat in the condenser, it returns to the flash tank to produce steam.

[0014] Furthermore, the reaction bed has an air-side inlet, a water-side inlet, a desorption gas outlet, and a water-side outlet;

[0015] The air outlet of the gas supply device is connected to the air inlet of the multiple reaction beds through multiple air-side inlet pipelines.

[0016] The exhaust device is connected to the desorption gas outlets of the reaction beds via multiple exhaust pipes.

[0017] Furthermore, the flash tank has a flash steam outlet, a flash tank saturated water outlet, and a high-temperature and high-pressure water inlet. The flash steam outlet is connected to the air-side inlet of the multiple reaction beds through multiple flash steam pipelines, and the flash tank saturated water outlet is connected to the water-side inlet of the multiple reaction beds through multiple flash tank saturated water pipelines.

[0018] Furthermore, the condenser has a condenser refrigerant inlet, a condenser refrigerant outlet, a condenser water inlet, and a condenser water outlet, and the condenser water outlet is connected to the high-temperature and high-pressure water inlet through a condenser water outlet pipeline;

[0019] The compressor has a compressor refrigerant inlet and a compressor refrigerant outlet, and the compressor refrigerant outlet is connected to the refrigerant inlet of the condenser;

[0020] The evaporator has an evaporator refrigerant inlet, an evaporator refrigerant outlet, a heat inlet, and a waste heat outlet; the heat inlet and waste heat outlet of the evaporator are respectively connected to a waste heat supply pipeline and a waste heat recovery pipeline; the outlet of the jet pump is connected to the refrigerant inlet of the compressor.

[0021] Furthermore, the gas-liquid separator has a gas outlet, a desorbed gas inlet, a refrigerant inlet, a refrigerant outlet, and a desorbed gas condensate outlet. The gas outlet is connected to a vacuum pump via a gas outlet pipeline, and the outlet of the vacuum pump is connected to a carbon dioxide collection or storage device.

[0022] The desorbed gas condensate outlet and the water-side outlet of the reaction bed are connected to the condenser water inlet via a three-way valve; the refrigerant inlet of the gas-liquid separator is connected to the refrigerant outlet of the condenser; the desorbed gas inlet of the gas-liquid separator is connected to the desorbed gas outlet of the reaction bed via a desorbed gas pipeline; the refrigerant inlet of the evaporator and the refrigerant inlet of the gas-liquid separator are both connected to the refrigerant outlet of the condenser via expansion valves; the refrigerant outlet of the evaporator and the refrigerant outlet of the gas-liquid separator converge at the inlet of the ejector pump.

[0023] Furthermore, valves are provided on the air-side inlet pipeline of the reaction bed, the exhaust pipeline, the desorption gas pipeline, the saturated water pipeline of the flash tank, the flash steam pipeline, and the water-side outlet pipeline of the reaction bed between the water-side outlet of the reaction bed and the three-way valve.

[0024] Beneficial effects:

[0025] 1. This invention effectively recovers waste heat from the waste heat source by using an evaporator, making full use of low-quality energy and achieving energy saving and emission reduction.

[0026] 2. This invention effectively recovers waste heat from the heat source of the gas-liquid separator by coupling the gas-liquid separator of the continuous air carbon dioxide capture system and the evaporator of the steam heat pump system, making full use of the system's own energy and reducing the heat energy consumption of direct air carbon dioxide capture; at the same time, it reduces the water content of the product carbon dioxide gas and improves the purity of the carbon dioxide gas.

[0027] By utilizing dual heat sources and adding an ejector pump, the quality of the refrigerant fluid is improved, the temperature difference during compressor operation is reduced, and the system performance is enhanced.

[0028] The flash tank in the steam heat pump simultaneously provides high-temperature hot water and high-temperature steam to the continuous carbon dioxide capture system. This significantly improves the desorption rate and enhances the system's capture capacity.

[0029] High-temperature steam generated by the flash tank in the steam heat pump is used as purge gas for carbon dioxide desorption. After condensation, the desorbed carbon dioxide gas does not contain impurities other than some water vapor, thus improving the purity of the carbon dioxide product gas captured by the system.

[0030] 3. This invention patent provides a clean, efficient, and green heat pump type continuous direct capture system for carbon dioxide in the air, which can continuously capture carbon dioxide from the air. The captured carbon dioxide gas has high purity and can be used to prepare carbonated beverages and chemicals such as methanol after collection, which has certain commercial value. At the same time, the captured carbon dioxide can be permanently stored by landfilling underground. Attached Figure Description

[0031] Figure 1 A schematic diagram of a direct air carbon capture system assisted by a circulating steam heat pump provided by the present invention; wherein, 1, gas supply device; 2, air-side inlet pipe of reaction bed A; 3, air-side inlet valve of reaction bed A; 4, reaction bed A; 5, exhaust pipe valve of exhaust A; 6, exhaust pipe A; 7, exhaust main pipe; 8, exhaust device; 9, jet pump outlet pipe; 10, compressor; 11, condenser inlet pipe; 12, condenser; 13, first-stage expansion valve inlet pipe; 14, first-stage expansion... 15. Expansion valve; 16. Gas-liquid separator inlet pipe; 17. Gas-liquid separator; 18. Gas-liquid separator outlet pipe; 19. Secondary expansion valve inlet pipe; 20. Evaporator; 21. Evaporator outlet pipe; 22. Ejector pump; 23. Waste heat supply pipe; 24. Waste heat recovery pipe; 25. Condenser water inlet pipe; 26. Condenser water outlet pipe; 27. Flash tank; 28. Flash steam main pipe; 29. ​​Flash steam B pipe; 30. 31. Flash steam B pipeline valve; 32. Reactor bed B; 33. Desorbed gas B pipeline valve; 34. Desorbed gas B pipeline; 35. Desorbed gas main pipeline; 36. Desorbed gas condensate pipeline; 37. Flash tank saturated water pipeline; 38. Reactor bed B water side inlet valve; 39. Reactor bed B water side outlet valve; 40. Reactor bed B water side outlet pipeline; 41. Three-way valve; 42. Gas outlet pipeline of gas-liquid separator; 43. Vacuum pump; 44. Product gas pipeline; 45. Air-side inlet pipeline of reaction bed B; 46. Air-side inlet valve of reaction bed B; 47. Exhaust gas pipeline valve of B; 48. Exhaust gas pipeline of B; 49. Flash steam pipeline of A; 50. Flash steam pipeline valve of A; 51. Desorption gas pipeline valve of A; 52. Desorption gas pipeline of A; 53. Saturated water pipeline of flash tank A; 54. Water-side inlet valve of reaction bed A; 55. Water-side outlet valve of reaction bed A; 56. Water-side outlet pipeline of reaction bed A. Detailed Implementation

[0032] Example 1

[0033] refer to Figure 1 A steam heat pump-assisted direct air carbon capture system, comprising:

[0034] An air carbon capture unit includes multiple parallel reaction beds and an air supply device 1 and an exhaust device 8 connected to the reaction beds. The reaction beds are used for the adsorption and removal of air carbon.

[0035] The waste heat recovery unit includes a waste heat supply pipeline 23, an evaporator 20, and a waste heat return pipeline 24 connected in sequence.

[0036] The refrigerant circulation unit includes a compressor 10, a condenser 12, an expansion valve, an evaporator 20, and an ejector pump 22, which are connected in sequence to form a circulation loop. The gas-liquid separator 16 is connected to the reaction bed, the condenser 12, the vacuum pump 43, and the ejector pump 22. The ejector pump 22 transfers the refrigerant output from the gas-liquid separator 16 and the evaporator 20 to the compressor 10. The reaction bed delivers vaporized carbon dioxide gas to the gas-liquid separator 16. The gas-liquid separator 16 separates water vapor and carbon dioxide gas. The water vapor is condensed and transferred to the condenser 12, and the carbon dioxide gas is transferred to the vacuum pump 43.

[0037] Flash tank 27 is connected to the reaction bed and condenser 12 respectively. Flash tank 27 is used to supply steam and saturated water to the reaction bed.

[0038] In this embodiment, the air carbon capture unit includes reaction bed A4 and reaction bed B31. Reaction beds A and B operate continuously, one for adsorption and the other for desorption. Reaction beds A and B do not necessarily represent only two beds; for example, assuming the system adsorption time is 1 hour and the desorption time is 0.5 hours, reaction bed A can represent two beds and reaction bed B can represent one bed. That is, at any given time, one reaction bed is desorbing while two reaction beds are adsorbing, achieving a continuous adsorption-desorption effect.

[0039] In this embodiment, when the reaction bed is in an adsorption state, air enters the reaction bed through the gas supply device 1, where carbon dioxide in the air is captured by the reaction bed, and gas without carbon dioxide flows out through the exhaust device 8 and is discharged into the atmosphere.

[0040] In this embodiment, the exhaust device 8 is a carbon dioxide-free air exhaust device that flows through the reaction bed A4 and the reaction bed B31, preferably an exhaust head; the air supply device 1 only needs to be able to overcome the friction resistance, and can be an air compressor or a fan, preferably an air compressor.

[0041] More specifically, both the vacuum pump 43 and the exhaust device 8 are normally open. When the reaction bed A4 adsorbs, the reaction bed B31 desorbs, and the gas flow from the reaction bed A4 flows to the exhaust device 8, while the gas flow from the reaction bed B31 flows to the vacuum pump 43. Conversely, when the states switch, the gas flow from the reaction bed A4 flows to the vacuum pump 43, and the gas flow from the reaction bed B31 flows to the exhaust device 8.

[0042] In this embodiment, the compressor 10, condenser 12, expansion valve, evaporator 20 and ejector pump 22, which are connected in sequence to form a circulation loop, constitute the first circulation loop of the refrigerant. The condenser 12, gas-liquid separator 16, ejector pump 22 and compressor 10 form the second circulation loop of the refrigerant. The refrigerant absorbs the heat from the waste heat in the evaporator 20 and absorbs the heat released by the condensation of water vapor in the gas-liquid separator 16. The two streams of refrigerant that have absorbed heat converge in the compressor 10. After compression and upgrading, they provide heat to the water flowing through the condenser 12 so that the water reaches the temperature for steam generation after entering the flash tank 27.

[0043] In this embodiment, when the reaction bed is in a desorption state, the flash tank 27 generates steam and provides steam and saturated water to the reaction bed to meet the desorption temperature. The steam carries away the carbon dioxide gas captured in the reaction bed. The mixture of steam and carbon dioxide is cooled in the gas-liquid separator 16 to separate the carbon dioxide and condensed water. The carbon dioxide gas flows through the vacuum pump 43 for collection. The condensed water is discharged through the gas-liquid separator 16 and merges with the saturated water discharged from the flash tank 27 from the reaction bed into the condenser 12. After the condenser 12 absorbs heat, it returns to the flash tank 27 to produce steam.

[0044] In this embodiment, the reaction bed has an air-side inlet, a water-side inlet, a desorption gas outlet, and a water-side outlet;

[0045] The air compressor outlet is connected to the air inlets of reaction bed A4 and reaction bed B31 respectively through two air-side inlet pipelines of the reaction bed;

[0046] The exhaust device 8 is connected to the desorption gas outlets of the two reaction beds via two exhaust pipes.

[0047] In this embodiment, the flash tank 27 has a flash steam outlet, a flash tank saturated water outlet, and a high-temperature and high-pressure water inlet. The flash steam outlet is connected to the air-side inlet of reaction bed A4 and reaction bed B31 through two flash steam pipelines, respectively. The flash tank saturated water outlet is connected to the water-side inlet of reaction bed A4 and reaction bed B31 through two flash tank saturated water pipelines, respectively.

[0048] In this embodiment, the condenser 12 has a condenser refrigerant inlet, a condenser refrigerant outlet, a condenser water inlet, and a condenser water outlet. The condenser water outlet is connected to the high-temperature and high-pressure water inlet through the condenser water outlet pipe 26.

[0049] The compressor 10 has a compressor refrigerant inlet and a compressor refrigerant outlet, and the compressor refrigerant outlet is connected to the condenser refrigerant inlet;

[0050] The evaporator 20 has an evaporator refrigerant inlet, an evaporator refrigerant outlet, a heat inlet, and a waste heat outlet; the heat inlet and waste heat outlet of the evaporator 20 are connected to the waste heat supply pipeline 23 and the waste heat recovery pipeline 24, respectively; the outlet of the jet pump 22 is connected to the compressor refrigerant inlet.

[0051] In this embodiment, the gas-liquid separator 16 has a gas outlet, a desorbed gas inlet, a refrigerant inlet, a refrigerant outlet, and a desorbed gas condensate outlet. The gas outlet is connected to the vacuum pump 43 via the gas outlet pipeline 42. The outlet of the vacuum pump 43 is connected to the carbon dioxide collection or storage device via the product gas pipeline 44.

[0052] The desorbed gas condensate outlet and the water-side outlet of the reaction bed are connected to the condenser water inlet via a three-way valve; the refrigerant inlet of the gas-liquid separator is connected to the refrigerant outlet of the condenser; the desorbed gas inlet of the gas-liquid separator 16 is connected to the desorbed gas outlet of the reaction bed via a desorbed gas pipeline; the refrigerant inlet of the evaporator and the refrigerant inlet of the gas-liquid separator are both connected to the refrigerant outlet of the condenser via an expansion valve; the refrigerant outlet of the evaporator and the refrigerant outlet of the gas-liquid separator converge at the inlet of the jet pump 22.

[0053] Specifically, the condenser refrigerant outlet is connected to the first interface of the first-stage expansion valve 14 through the first-stage expansion valve inlet pipe 13, the second interface of the first-stage expansion valve 14 is connected to the refrigerant inlet of the gas-liquid separator through the gas-liquid separator inlet pipe 15, the third interface of the first-stage expansion valve 14 is connected to the refrigerant inlet of the evaporator through the second-stage expansion valve inlet pipe 18, and a second-stage expansion valve 19 is provided on the second-stage expansion valve inlet pipe 18.

[0054] In this embodiment, valves are provided on the air-side inlet pipeline, exhaust pipeline, desorption gas pipeline, flash tank saturated water pipeline, flash steam pipeline, and the water-side outlet pipeline of the reaction bed between the water-side outlet of the reaction bed and the three-way valve 41.

[0055] Specifically, the air-side inlet pipes of the two reaction beds are respectively set as air-side inlet pipe 2 of reaction bed A and air-side inlet pipe 45 of reaction bed B, which are connected to reaction bed A4 and reaction bed B31 respectively. Air-side inlet pipe 2 of reaction bed A and air-side inlet pipe 45 of reaction bed B are respectively equipped with air-side inlet valve 3 of reaction bed A and air-side inlet valve 46 of reaction bed B.

[0056] The exhaust device 8 is connected to the desorption gas outlets of reaction bed A4 and reaction bed B31 through two exhaust pipes respectively.

[0057] Among them, the two exhaust pipes are respectively set as exhaust pipe A 6 and exhaust pipe B 48. Exhaust pipe A 5 and exhaust pipe B 48 are respectively installed on exhaust pipe A 6 and exhaust pipe B 48 and converge into exhaust main pipe 7. Exhaust main pipe 7 is connected to exhaust device 8.

[0058] The flash steam outlet is connected to the flash steam main pipeline 28. The flash steam main pipeline 28 is connected to the air-side inlet of the reaction bed A4 and the reaction bed B31 through two flash steam pipelines respectively. The two flash steam pipelines are designated as flash steam pipeline A 49 and flash steam pipeline B 29 respectively. Flash steam pipeline A 50 and flash steam pipeline B 30 are respectively installed on flash steam pipeline A 49 and flash steam pipeline B 29.

[0059] The flash tank saturated water outlet is connected to the water-side inlet of reaction bed A4 and reaction bed B31 via two flash tank saturated water pipelines, respectively. The two flash tank saturated water pipelines are designated as flash tank saturated water pipeline 36 and flash tank saturated water A pipeline 53, respectively. Flash tank saturated water pipeline 36 and flash tank saturated water A pipeline 53 are respectively equipped with reaction bed B water-side inlet valve 37 and reaction bed A water-side inlet valve 54.

[0060] The water-side outlets of reaction bed A4 and reaction bed B31 are connected to the main water-side outlet pipeline 40 of reaction bed A via water-side outlet pipeline 56 and water-side outlet pipeline 39 of reaction bed B, respectively. The main water-side outlet pipeline 40 of reaction bed B is connected to the first interface of the three-way valve 41. Water-side outlet valve 55 of reaction bed A and water-side outlet valve 38 of reaction bed B are respectively installed on water-side outlet pipeline 56 of reaction bed A and water-side outlet pipeline 39 of reaction bed B.

[0061] The second port of the three-way valve 41 is connected to the condenser water inlet through the condenser water inlet pipe 25, and the third port of the three-way valve 41 is connected to the desorbed gas condensate outlet through the desorbed gas condensate pipe 35.

[0062] The desorption gas outlets of reaction bed A4 and reaction bed B31 are respectively connected to desorption gas pipeline A 52 and desorption gas pipeline B 33, which are connected to desorption gas main pipeline 34, and desorption gas main pipeline 34 is connected to desorption gas inlet of gas-liquid separator 16; desorption gas pipeline A valve 51 and desorption gas pipeline B valve 32 are installed on desorption gas pipeline A 52 and desorption gas pipeline B 33.

[0063] The refrigerant outlets of the evaporator and the gas-liquid separator are respectively connected to the inlet of the ejector pump 22 via the evaporator outlet pipe 21 and the gas-liquid separator outlet pipe 17. The outlet of the ejector pump 22 is connected to the refrigerant inlet of the compressor via the ejector pump outlet pipe 9.

[0064] The compressor refrigerant outlet and the condenser refrigerant inlet are connected by condenser inlet pipe 11.

[0065] like Figure 1 As shown, the solid line represents the adsorption process in reaction bed A4 and the desorption process in reaction bed B31. If the corresponding solid line is replaced with... Figure 1 The dashed line shown represents the process of desorption in reaction bed A and adsorption in reaction bed B. The switching between the desorption and adsorption processes can be accomplished by changing the opening and closing of the corresponding valves.

[0066] Furthermore, the steam heat pump-assisted direct air carbon capture system provided in this embodiment can also be applied to other carbon capture systems, such as replacing air with desulfurized and denitrified low-temperature flue gas, carbon dioxide-containing biogas, etc., and it is equally applicable.

[0067] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A steam heat pump-assisted direct air carbon capture system, characterized in that, include: An air carbon capture unit includes multiple reaction beds arranged in parallel and an air supply device and an exhaust device connected to the reaction beds, wherein the reaction beds are used for the adsorption and desorption of air carbon. Waste heat recovery unit, the waste heat recovery unit includes a waste heat supply pipeline, an evaporator and a waste heat return pipeline connected in sequence; A refrigerant circulation unit includes a compressor, a condenser, an expansion valve, an evaporator, a gas-liquid separator, and an ejector pump, which are connected in sequence to form a circulation loop. The gas-liquid separator is connected to the reaction bed, the condenser, a vacuum pump, and the ejector pump. The ejector pump transfers the refrigerant output from the gas-liquid separator and the evaporator to the compressor. The reaction bed delivers vaporized carbon dioxide gas to the gas-liquid separator. The gas-liquid separator separates water vapor and carbon dioxide gas. The water vapor is condensed and transferred to the condenser, and the carbon dioxide gas is transferred to the vacuum pump. A flash tank is connected to the reaction bed and the condenser, respectively, and is used to supply steam and saturated water to the reaction bed.

2. The steam heat pump-assisted direct air carbon capture system according to claim 1, characterized in that, When the reaction bed is in an adsorption state, air enters the reaction bed through the gas supply device, where carbon dioxide in the air is captured by the reaction bed, and gas without carbon dioxide flows out into the atmosphere through the exhaust device.

3. The steam heat pump-assisted direct air carbon capture system according to claim 2, characterized in that, The compressor, condenser, expansion valve, evaporator, and ejector pump, which are connected in sequence to form a circulation loop, constitute the first refrigerant circulation loop. The condenser, gas-liquid separator, ejector pump, and compressor form the second refrigerant circulation loop. In this loop, the refrigerant absorbs heat from the waste heat in the evaporator and heat released by the condensation of water vapor in the gas-liquid separator. The two streams of refrigerant that have absorbed heat converge in the compressor. After compression and upgrading, they provide heat to the water flowing through the condenser so that the water reaches the temperature required to generate steam after entering the flash tank.

4. The steam heat pump-assisted direct air carbon capture system according to claim 3, characterized in that, When the reaction bed is in a desorption state, the flash tank generates steam and supplies steam and saturated water to the reaction bed to meet the desorption temperature. The steam carries away the carbon dioxide gas captured in the reaction bed. The mixture of steam and carbon dioxide is cooled in the gas-liquid separator to separate the carbon dioxide and condensed water. The carbon dioxide gas is collected by the vacuum pump. The condensed water is discharged through the gas-liquid separator and merges with the saturated water discharged from the flash tank of the reaction bed into the condenser. After absorbing heat in the condenser, it returns to the flash tank to produce steam.

5. The direct air carbon capture system assisted by a steam heat pump according to claim 1, characterized in that, The reaction bed has an air-side inlet, a water-side inlet, a desorbed gas outlet, and a water-side outlet; The air outlet of the gas supply device is connected to the air inlet of the multiple reaction beds through multiple air-side inlet pipelines. The exhaust device is connected to the desorption gas outlets of the reaction beds via multiple exhaust pipes.

6. The steam heat pump-assisted direct air carbon capture system according to claim 5, characterized in that, The flash tank has a flash steam outlet, a flash tank saturated water outlet, and a high-temperature and high-pressure water inlet. The flash steam outlet is connected to the air-side inlet of the multiple reaction beds through multiple flash steam pipelines, and the flash tank saturated water outlet is connected to the water-side inlet of the multiple reaction beds through multiple flash tank saturated water pipelines.

7. The steam heat pump-assisted direct air carbon capture system according to claim 6, characterized in that, The condenser has a condenser refrigerant inlet, a condenser refrigerant outlet, a condenser water inlet, and a condenser water outlet. The condenser water outlet is connected to the high-temperature and high-pressure water inlet through a condenser water outlet pipeline. The compressor has a compressor refrigerant inlet and a compressor refrigerant outlet, and the compressor refrigerant outlet is connected to the refrigerant inlet of the condenser; The evaporator has an evaporator refrigerant inlet, an evaporator refrigerant outlet, a heat inlet, and a waste heat outlet; the heat inlet and waste heat outlet of the evaporator are respectively connected to a waste heat supply pipeline and a waste heat recovery pipeline; the outlet of the jet pump is connected to the refrigerant inlet of the compressor.

8. The steam heat pump-assisted direct air carbon capture system according to claim 7, characterized in that, The gas-liquid separator has a gas outlet, a desorbed gas inlet, a refrigerant inlet, a refrigerant outlet, and a desorbed gas condensate outlet. The gas outlet is connected to a vacuum pump via a gas outlet pipeline, and the outlet of the vacuum pump is connected to a carbon dioxide collection or storage device. The desorbed gas condensate outlet and the water-side outlet of the reaction bed are connected to the condenser water inlet via a three-way valve; the refrigerant inlet of the gas-liquid separator is connected to the refrigerant outlet of the condenser; the desorbed gas inlet of the gas-liquid separator is connected to the desorbed gas outlet of the reaction bed via a desorbed gas pipeline; the refrigerant inlet of the evaporator and the refrigerant inlet of the gas-liquid separator are both connected to the refrigerant outlet of the condenser via expansion valves; the refrigerant outlet of the evaporator and the refrigerant outlet of the gas-liquid separator converge at the inlet of the ejector pump.

9. The steam heat pump-assisted direct air carbon capture system according to claim 8, characterized in that, Valves are installed on the air-side inlet pipeline of the reaction bed, the exhaust pipeline, the desorption gas pipeline, the saturated water pipeline of the flash tank, the flash steam pipeline, and the water-side outlet pipeline of the reaction bed between the water-side outlet of the reaction bed and the three-way valve.

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