Water-saving direct air carbon capture system and method

Abstract

The invention discloses a water-saving type direct air carbon capture system and method, dry air is provided for the adsorption process of a direct air carbon capture technology by means of a continuous air water taking technology, and the air dehumidification process of a traditional DAC technology is avoided. Water collected from air provides water resources for the desorption process of the DAC, consumption of a large amount of fresh water resources in a deployment place by a traditional DAC technology is avoided, a DAC system and an existing air water taking device are designed in an integrated mode, the air water taking technology and the DAC technology share one set of fan system and condensate water system, the device of the DAC system is simplified, the equipment utilization rate is increased, and the energy consumption of the DAC system is reduced. And according to the environment prediction humidity, the air water taking amount is accurately regulated and controlled so as to meet the water consumption requirement of the DAC system.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide capture and utilization, and in particular to a water-saving direct air carbon capture system and method. Background Art

[0002] Direct air carbon capture (DAC) is a highly promising carbon capture technology. It absorbs CO2 from the air using an adsorbent, then desorbs and separates the CO2 and regenerates the adsorbent through heating or spray desorption. Wet regeneration processes, such as spray desorption, are considered a key development direction for DAC due to their low energy consumption. However, existing wet regeneration technologies all suffer from high water consumption, which significantly limits the widespread application of DAC technology.

[0003] Air water extraction technology is a water resource utilization technology that can be widely applied in various environments. The main process of this technology is to collect water from the air through the adsorption-desorption cycle of water vapor. The distribution of water vapor in the atmosphere is not restricted by region. Even in desert areas, the water content in the air exceeds 10g / m 3 Therefore, this technology can provide liquid water resources economically and efficiently on a global scale without causing a major impact on the global water ecological cycle.

[0004] Data shows that existing air water extraction technologies mainly focus on water resource acquisition methods such as outdoor water extraction and offshore water extraction. They do not consider the coupling of water extraction technology with other process technologies, and fail to achieve precise control of the air water extraction rate.

[0005] Chinese patent document CN117738287A discloses a "highly efficient and energy-saving adaptive all-weather composite air water extraction device." This device utilizes an integrated heat pump to drive air water extraction. This technology achieves efficient and continuous air water extraction in a wide range of relative humidity environments by connecting multiple devices in series. However, this technical solution fails to consider the integration of water extraction technology with other process technologies and fails to precisely control the air water extraction rate. Summary of the Invention

[0006] The present invention mainly solves the technical problems that the original technical solution does not consider the coupling and docking of water intake technology with other process technologies and fails to achieve precise control of the air water intake rate. It provides a water-saving direct air carbon capture system and method, which uses continuous air water intake technology to provide dry air for the adsorption process of the direct air carbon capture technology, avoiding the air dehumidification process of the traditional DAC technology; the moisture collected from the air provides water resources for the desorption process of DAC, avoiding the large-scale consumption of fresh water resources in the deployment site by the traditional DAC technology, and integrates the DAC system with the existing air water intake device. The air water intake technology and DAC technology share a set of fan systems and condensate systems, which streamlines the DAC system equipment and improves equipment utilization. The humidity is predicted according to the environment, and the air water intake amount is precisely controlled to meet the water consumption requirements of the DAC system.

[0007] The above technical problems of the present invention are mainly solved by the following technical solutions: A water-saving direct air carbon capture system includes an air water intake system, the input of which receives ambient air, and the output of which is connected to a water storage tank and a DAC adsorption system, respectively. The output of the water storage tank is connected to the DAC adsorption system. Continuous air water intake technology provides dry air for the adsorption process of the direct air carbon capture technology, avoiding the air dehumidification process required by traditional DAC technology. Water collected from the air provides water for the DAC desorption process, avoiding the large-scale consumption of freshwater resources at the deployment site by traditional DAC technology. The DAC system is also integrated with existing air water intake equipment, sharing a common fan system and condensate water system. This streamlines the DAC system's equipment and improves equipment utilization. Based on the predicted humidity of the environment, the air water intake volume can be precisely controlled to meet the DAC system's water consumption requirements.

[0008] Preferably, the input end of the air water intake system is connected to the output end of the fan, and the fan heats the ambient air while inputting the ambient air.

[0009] Preferably, the air water intake system includes a moisture adsorption bed and a water vapor output end, and the water vapor output end is connected to the water storage tank input end through the first pipeline of the condenser.

[0010] Preferably, a semiconductor refrigeration plate is further included, and the hot end of the semiconductor refrigeration plate is close to the moisture adsorption bed for heating and desorption.

[0011] Preferably, the cold end of the semiconductor refrigeration plate is close to the condenser tube for condensing water vapor, and a hydrophobic wedge-shaped groove is provided in the condenser tube.

[0012] Preferably, the air water intake system includes a dry air output end, which is connected to the input end of the DAC adsorption system. The DAC adsorption system includes a first CO2 adsorption bed and a second CO2 adsorption bed.

[0013] Preferably, the output end of the DAC adsorption system includes an air exhaust output end after CO2 removal and a high-humidity CO2 output end.

[0014] Preferably, the high-humidity CO2 output end is connected to the gas storage tank after condensation and water removal through the second pipeline in the condenser.

[0015] A method for operating a water-saving direct air carbon capture system comprises the following steps: S1. Ambient air is introduced into the air water intake system to absorb moisture; S2. The dehydrated dry air is introduced into the DAC adsorption system to adsorb CO2. The adsorbed water is then desorbed and condensed for collection. After the DAC adsorption system is saturated with CO2, it uses the collected water for spray desorption; S4. The desorbed high-humidity CO2 is introduced into the second pipeline of the condenser for condensation and dehydration to collect moisture and dry CO2 respectively; S5. The DAC adsorption system after desorption is dried by hot air provided by the fan and then proceeds to the next round of CO2 adsorption.

[0016] Preferably, the total gas flow Q1 of the fan, the water vapor flow Q2 and the semiconductor heating temperature T are controlled to control the water vapor desorption rate η, so that the water collection period and the CO2 adsorption and desorption period are balanced.

[0017] The beneficial effects of the present invention are: using continuous air water intake technology to provide dry air for the adsorption process of direct air carbon capture technology, avoiding the air dehumidification process of traditional DAC technology; the moisture collected from the air provides water resources for the desorption process of DAC, avoiding the large-scale consumption of freshwater resources at the deployment site by traditional DAC technology, and the DAC system is integrated with the existing air water intake device. The air water intake technology and DAC technology share a set of fan systems and condensed water systems, which streamlines the DAC system equipment and improves equipment utilization. The humidity is predicted according to the environment, and the air water intake amount is accurately controlled to meet the water consumption requirements of the DAC system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a principle connection structure diagram of the present invention.

[0019] Figure 2 It is a flow chart of the present invention.

[0020] In the figure, 1 is ambient air, 2 is heating fan, 3 is air water intake system, 4 is PLC control system, 5 is semiconductor refrigeration plate, 6 is condenser, 7 is water storage tank, 8 is first CO2 adsorption bed, 9 is second CO2 adsorption bed, and 10 is gas storage tank. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clear, the technical solutions of the present application are further described in detail below through examples and in combination with the accompanying drawings. It should be understood that the specific implementation method described here is only an optimal embodiment of the present application, which is only used to explain the present application and does not limit the scope of protection of the present application. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] Chinese patent CN114515494B discloses an energy-saving system and method for direct air capture of carbon dioxide with precise ion control. By coupling an electrochemical regeneration system with a valence ion screening device, the system precisely prepares and controls the amount of spray liquid. This achieves precise control of the CO2 regeneration process and improves the efficiency of the spray liquid. However, this control system consumes a lot of energy and does not address the problem of the spray liquid's high water consumption.

[0023] Chinese patent CN117738287A discloses a highly efficient, energy-efficient, adaptive, all-weather composite air-to-water extraction device that uses an integrated heat pump to drive air-to-water extraction. This technology connects multiple devices in series to achieve efficient, continuous air-to-water extraction in a wide range of relative humidity environments.

[0024] However, air-to-water extraction technologies, such as those represented by this patent, primarily focus on water acquisition methods such as field and offshore water extraction. They fail to consider the integration of water extraction technology with other process technologies and fail to precisely control the air-to-water extraction rate. Furthermore, the existing DAC technology's spray desorption process consumes significant amounts of water, significantly limiting its widespread application.

[0025] The present invention provides a solution that uses a fan to introduce ambient air of a certain humidity into an air dehydration system. The adsorption bed in the air dehydration system absorbs moisture from the air, and dry air is introduced into a DAC system as captured intake air. The DAC system directly adsorbs CO2 from this intake air. A PLC control unit and a gas mass flowmeter precisely control the gas flow in and out of the air dehydration system and the DAC system. The moisture adsorbed by the air dehydration system is heated by the hot end of a semiconductor refrigeration chip and introduced into a condensation system as water vapor. The condensed moisture is then directed to a water storage tank, with the cold end of the semiconductor refrigeration chip providing cooling for the condensation system. The moisture in the water storage tank is pumped into the DAC adsorption bed for spray desorption. The desorbed high-humidity CO2 is then introduced into the condensation system through a pipeline for dehydration. The collected moisture is then transferred to a water storage tank for recycling, and the dried CO2 is then transferred to a gas storage tank for subsequent use. After desorption, the DAC adsorption bed is dried with hot air provided by the fan (this fan is a heating fan, but only provides hot air when drying the CO2 adsorption bed) before the next round of CO2 adsorption can begin. The interior of the condenser tubes features hydrophobic wedge-shaped grooves. The Laplace liquid pressure differential generated during the condensation process enables self-driven flow guidance and rapid transport of the liquid. A humidity prediction model is used to predict ambient humidity. A PLC control unit and flow meter precisely regulate the operating status and water intake rate of the air water intake equipment, ensuring a dynamic balance between air water intake and DAC water consumption, and maintaining a stable liquid level in the water storage tank.

[0026] Compared with the prior art, the beneficial effects of the present invention are: (1) With the help of air water extraction technology, efficient acquisition of water resources is achieved, providing stable water resources for DAC, avoiding the large-scale consumption of freshwater resources in the deployment area by traditional DAC technology, and broadening the scope of application of DAC technology.

[0027] (2) The hot and cold end energies of the semiconductor refrigeration plate of the air-to-water system are recycled and utilized separately to improve energy utilization efficiency (the heating and condensation of the traditional air-to-water technology each use a set of equipment).

[0028] (3) The DAC system is integrated with the existing air water extraction device. The air water extraction technology and DAC technology share a set of fan system and condensing water system, which simplifies the DAC system equipment and improves the equipment utilization rate (traditional DAC system and air water extraction system both have their own fans and condensing equipment).

[0029] (4) Based on the built-in humidity prediction model, the PLC control unit continuously predicts the ambient humidity and controls the operating load of the air water intake equipment and DAC equipment in real time. By adjusting parameters such as fan power, air flow meter, and desorption temperature, the desorption rate is dynamically adjusted to ensure the dynamic balance between air water intake and DAC water consumption, thereby achieving continuous and stable operation of the air water intake system and the DAC system.

[0030] Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flow charts. Although the flow charts describe the operations (or steps) as sequential processes, many of the operations (or steps) therein can be performed in parallel, concurrently, or simultaneously. In addition, the order of the operations can be rearranged. The process can be terminated when its operations are completed, but can also have additional steps not included in the figures; the process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0031] The technical solution of the present invention will be further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0032] Example 1: A water-saving direct air carbon capture system of this embodiment, such as Figure 1 As shown, it includes an air water intake system 3, the input end of the air water intake system 3 inputs ambient air 1, and the output end is connected to a water storage tank 7 and a DAC adsorption system respectively, and the output end of the water storage tank 7 is connected to the DAC adsorption system.

[0033] The input end of the air water intake system 3 is connected to the output end of the fan, and the fan heats the ambient air 1 while inputting the ambient air 1. The ambient air 1 is introduced into the air water intake system 3 through the heating fan 2. The PLC control system 4 accurately controls the total gas flow Q1 (Q1 = 2000 ~ 6000m) of the fan according to the predicted environmental humidity H (H = 20 ~ 95% RH). 3 / h).

[0034] The air water intake system 3 includes a moisture adsorption bed, which fully absorbs moisture from the air. The primary adsorbent in the adsorption bed can be one or more of a hygroscopic salt, a metal-organic framework (MOF) material, or a polymer material, with an adsorption time of 1.0 to 3.0 hours. It also includes a water vapor output terminal, which connects to the input terminal of a water storage tank 7 via a first line of a condenser 6. The water storage tank 7 is equipped with a liquid level gauge. The air water intake system is initially operated at full capacity to draw water. When the water level reaches the set level V1 (V = 30-50 L) in the water storage tank, the DAC adsorption system begins operation.

[0035] The system further comprises a semiconductor refrigeration chip 5, the hot end of which is close to the moisture adsorption bed for heating and desorption. The hot end of the semiconductor refrigeration chip 5 is used to heat and desorb the adsorption bed of the air water intake system 3. The heating temperature is T (T = 70-90 ° C), the desorption time is 0.2-0.6 hours, and the desorption rate is η (η = 70-90%). The desorbed water vapor is introduced into the first pipeline of the condenser 6, and the water vapor flow rate is Q2 (Q2 = 500-2000m 3 / h). The cold end of the semiconductor refrigeration chip 5 approaches the condenser tube 6, which is equipped with a hydrophobic wedge-shaped groove to condense water vapor. The hydrophobic wedge-shaped groove inside the condenser tube creates a Laplace liquid pressure difference during the condensation process, which enables self-driven flow and rapid transport of the liquid. The condensation temperature is always 15°C lower than the ambient temperature. The condensed water is pumped into a water storage tank 7 for subsequent desorption in the DAC system.

[0036] The air water intake system 3 includes a dry air output terminal, which is connected to the input terminal of the DAC adsorption system. The DAC adsorption system includes a first CO2 adsorption bed 8 and a second CO2 adsorption bed 9. The dry air discharged from the air water intake system is introduced into the adsorption beds 8 and 9 of the DAC system through the air duct. The air flow rate of the air duct is Q3 (Q3 = 1000 ~ 3000m 3 / h), the adsorption time lasts for 1.5 to 2.0 hours, and the air after CO2 removal is exhausted.

[0037] The output of the DAC adsorption system includes an air exhaust output after CO2 removal and a high-humidity CO2 output. The high-humidity CO2 output is connected to a gas storage tank 10 after condensation and water removal through the second pipeline in the condenser 6. After the DAC system adsorption bed 8 or 9 reaches saturation, water collected from the water storage tank 7 is pumped into the DAC adsorption bed for spray desorption. CO2 is desorbed to a saturation of 0.52 and a desorption partial pressure of 2000 ppm. The desorption process lasts for 0.5 to 1.5 hours. The desorbed high-humidity CO2 is introduced into the second pipeline in the condenser 6 for condensation and water removal. The collected water enters the water storage tank 7 for recycling, and the dried CO2 is introduced into the gas storage tank 10 for subsequent use. After desorption, the DAC adsorption bed is dried with hot air provided by a fan (this fan is a heating fan and only provides hot air when drying the CO2 adsorption bed) before the next round of CO2 adsorption can be carried out. This drying process is a water-consuming step in the DAC system.

[0038] A method of operating a water-saving direct air carbon capture system, such as Figure 2 As shown, the following steps are included: S1. Ambient air is introduced into the air water intake system to absorb moisture; S2. The dehydrated dry air is introduced into the DAC adsorption system to adsorb CO2. The adsorbed water is then desorbed and condensed for collection. After the DAC adsorption system is saturated with CO2, it uses the collected water for spray desorption; S4. The desorbed, high-humidity CO2 is introduced into the second condenser pipe for condensation and dehydration, collecting the water and dry CO2 separately. S5. The desorbed DAC adsorption system is dried with hot air provided by the fan before the next round of CO2 adsorption. The total fan gas flow rate Q1, water vapor flow rate Q2, and semiconductor heating temperature T are controlled to control the water vapor desorption rate η, maintaining a balance between the water collection period and the CO2 adsorption and desorption period.

[0039] Since the DAC system has a fixed demand for water consumption, and changes in air humidity will affect the amount of water taken from the air, a humidity prediction model is built into the PLC system; the PLC system continuously performs real-time analysis of the ambient humidity in the next 3 hours, and controls the total gas flow Q1 of the fan, the water vapor flow Q2 and the semiconductor heating temperature T in real time through the PLC control unit and flow meter to control the desorption rate η, thereby accurately controlling the operating status and water intake rate of the air water intake equipment, so that the water collection rate of the air water intake system is constant at M (M = 0.6 ~ 1.4L / h), ensuring the dynamic balance between the air water intake and DAC water consumption (that is, the liquid level fluctuation in the water storage tank 7 is no more than 20%).

[0040] Example 2 The technical solution of the present invention is as follows Figure 1 As shown, it includes air water intake system, DAC system, PLC control system, semiconductor refrigeration system, and storage tank system.

[0041] The ambient air 1 is introduced into the air water intake system 3 through the heating fan 2. The PLC control system 4 accurately controls the total gas flow Q1 (Q1 = 2000 ~ 6000m) of the fan according to the predicted humidity H (H = 20 ~ 95% RH) of the environment. 3 / h); the moisture in the air is fully absorbed by the adsorption bed of the air water intake system 3. The main adsorbent of the adsorption bed can be one or more of hygroscopic salts, MOFs (metal organic frameworks) materials, polymer materials, etc., and the adsorption time is 1.0 to 3.0 hours.

[0042] The hot end of the semiconductor refrigeration sheet 5 is used to heat and desorb the adsorption bed of the air water intake system 3. The heating temperature is T (T = 70 ~ 90 ° C), the desorption time is 0.2 ~ 0.6h, the desorption rate is η (η = 70 ~ 90%), and the desorbed water vapor is introduced into the first pipeline of the condenser 6. The water vapor flow rate is Q2 (Q2 = 500 ~ 2000m 3 / h); the interior of the condensation pipeline is a hydrophobic wedge-shaped groove. The Laplace liquid phase pressure difference generated during the condensation process can achieve self-driven diversion and rapid transportation of the liquid. The condensation temperature is always 15°C lower than the external temperature; the water collected by condensation is pumped into the water storage tank 7 for subsequent desorption process of the DAC system.

[0043] A liquid level gauge is provided in the water storage tank 7. The air water intake system first operates at full load to take water. When the water level reaches the set liquid level V1 (V=30-50L) in the water storage tank, the DAC adsorption system starts working.

[0044] The dry air discharged from the air water intake system is introduced into the adsorption beds 8 and 9 of the DAC system through the air duct. The air flow rate of the air duct is Q3 (Q3 = 1000 ~ 3000m 3 / h), the adsorption time lasts for 1.5 to 2.0 hours, and the air after CO2 removal is exhausted.

[0045] After the DAC system's adsorption bed 8 or 9 reaches saturation, water collected from the water storage tank 7 is pumped into the DAC adsorption bed for spray desorption. CO2 is desorbed until the saturation reaches 0.52 and the desorption partial pressure reaches 2000 ppm. The desorption process lasts for 0.5 to 1.5 hours. The desorbed, high-humidity CO2 is introduced into the second pipeline of the condenser 6 for condensation and dehydration. The collected water enters the water storage tank 7 for recycling, and the dried CO2 is introduced into the gas storage tank 10 for subsequent use. The desorbed DAC adsorption bed is dried with hot air provided by a fan (this fan is a heating fan and only provides hot air when drying the CO2 adsorption bed) before the next round of CO2 adsorption can begin. This drying process is a water-consuming step in the DAC system.

[0046] Since the DAC system has a fixed demand for water consumption, and changes in air humidity will affect the amount of water taken from the air, a humidity prediction model is built into the PLC system; the PLC system continuously performs real-time analysis of the ambient humidity in the next 3 hours, and controls the total gas flow Q1 of the fan, the water vapor flow Q2 and the semiconductor heating temperature T in real time through the PLC control unit and flow meter to control the desorption rate η, thereby accurately controlling the operating status and water intake rate of the air water intake equipment, so that the water collection rate of the air water intake system is constant at M (M = 0.6 ~ 1.4L / h), ensuring the dynamic balance between the air water intake and DAC water consumption (that is, the liquid level fluctuation in the water storage tank 7 is no more than 20%).

[0047] The DAC system features two independent CO2 adsorption-desorption modules, each connected to the airflow path of the air-to-water system. The two modules alternately perform adsorption and desorption processes, enabling continuous operation of the DAC system. Two independent condensation lines ensure continuous operation of the air-to-water system, ensuring the required water resources for the DAC system's desorption process. Energy from the hot and cold ends of the semiconductor refrigeration plate is recycled separately to improve energy efficiency. The condenser tubes feature hydrophobic wedge-shaped grooves. The Laplace liquid pressure differential generated during the condensation process enables self-driven flow guidance and rapid transport of the liquid. A PLC control unit with a built-in humidity prediction model and flow meter precisely regulate the operating status and water extraction rate of the air-to-water system, ensuring a dynamic balance between air extraction and DAC water consumption.

[0048] Compared with the existing technology, the beneficial effects of the present invention are as follows: (1) With the help of air water extraction technology, efficient acquisition of water resources is achieved, providing stable water resources for DAC, avoiding the large-scale consumption of fresh water resources in the deployment area by traditional DAC technology, and broadening the scope of application of DAC technology. (2) The hot end and cold end energy of the semiconductor refrigeration plate of the air water extraction system are recycled and utilized separately, thereby improving energy utilization efficiency (the heating and condensation of traditional air water extraction technology each use a set of equipment). (3) The DAC system is integrated with the existing air water extraction device. The air water extraction technology and DAC technology share a set of fan system and condensing water system, which simplifies the device of the DAC system and improves the equipment utilization rate (the traditional DAC system and air water extraction system both have their own fans and condensing equipment). (4) According to the built-in humidity prediction model, the PLC control unit continuously predicts the ambient humidity and controls the operating load of the air water extraction equipment and DAC equipment in real time. By adjusting parameters such as fan power, air flow meter, desorption temperature, etc., the desorption rate is dynamically adjusted to ensure the dynamic balance between the air water extraction amount and the DAC water consumption, and to achieve continuous and stable operation of the air water extraction system and the DAC system.

[0049] Example parameters: When the DAC system is operating normally (the fan flow rate is 2000m 3 / h), the water consumption rate is about 0.8kg / h. Based on the parameters in the above DAC operation process, the following three embodiment parameters are proposed (the implementation process is the same as described above, only the parameter changes are stated here): (1) When the DAC system is running stably, the air duct flow rate Q3 is 2000m 3 / h, CO2 desorption to saturation of 0.52, desorption partial pressure of 2000ppm, desorption time 1.0h; when the humidity prediction module determines that the ambient humidity in the next 3 hours will be 30%RH, the PLC control unit 4 automatically adjusts the total fan flow Q1 to 5000m 3 / h, semiconductor heating temperature T is 90℃, water vapor flow rate Q2 is 3000m 3 / h, maintaining the desorption rate η at 87%, and achieving a water intake rate of 0.8kg / h.

[0050] (2) When the DAC system is running stably, the air duct flow rate Q3 is 2000m 3 / h, CO2 desorption to saturation of 0.52, desorption partial pressure of 2000ppm, desorption time 1.0h; when the humidity prediction module determines that the ambient humidity in the next 3 hours will be 54%RH, the PLC control unit 4 automatically adjusts the total fan flow Q1 to 3500m 3 / h, semiconductor heating temperature T is 85℃, steam flow rate Q2 is 1500m 3 / h, maintaining the desorption rate η at 80%, and achieving a water intake rate of 0.8kg / h.

[0051] (3) When the DAC system is running stably, the air duct flow rate Q3 is 2000m 3 / h, CO2 desorption to saturation of 0.52, desorption partial pressure of 2000ppm, desorption time 1.0h; when the humidity prediction module determines that the ambient humidity in the next 3 hours will be 83%RH, the PLC control unit 4 automatically adjusts the total fan flow Q1 to 3000m 3 / h, semiconductor heating temperature T is 80℃, water vapor flow rate Q2 is 1000m 3 / h, maintaining the desorption rate η at 76%, and achieving a water intake rate of 0.8kg / h.

[0052] The specific embodiments described herein are merely examples of the spirit of the present invention. The above embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of this application. It should be pointed out that those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or replace them in a similar manner, but they will not deviate from the spirit of the present application or exceed the scope defined by the attached claims. For those of ordinary skill in the art, multiple variations and improvements can be made without departing from the concept of the present application. Therefore, the scope of protection of the present application shall be based on the attached claims.

Claims

1. A water-saving direct air carbon capture system, comprising an air water intake system (3), characterized in that: The input end of the air water intake system (3) inputs ambient air (1), and the output end is respectively connected to a water storage tank (7) and a DAC adsorption system, wherein the output end of the water storage tank (7) is connected to the DAC adsorption system.

2. The water-saving direct air carbon capture system according to claim 1, characterized in that: The input end of the air water intake system (3) is connected to the output end of the fan, and the fan heats the ambient air (1) while inputting the ambient air (1).

3. The water-saving direct air carbon capture system according to claim 1, characterized in that: The air water intake system (3) comprises a moisture adsorption bed and a water vapor output end, wherein the water vapor output end is connected to the input end of the water storage tank (7) through a first pipeline of the condenser (6).

4. The water-saving direct air carbon capture system according to claim 3, characterized in that: It also includes a semiconductor refrigeration plate (5), the hot end of the semiconductor refrigeration plate (5) is close to the moisture adsorption bed for heating and desorption.

5. The water-saving direct air carbon capture system according to claim 4, characterized in that: The cold end of the semiconductor refrigeration plate (5) is close to the condenser (6) for condensing water vapor, and a hydrophobic wedge-shaped groove is provided in the condenser (6).

6. A water-saving direct air carbon capture system according to claim 3, 4 or 5, characterized in that: The air water intake system (3) comprises a dry air output end, which is connected to the input end of a DAC adsorption system. The DAC adsorption system comprises a first CO2 adsorption bed (8) and a second CO2 adsorption bed (9).

7. A water-saving direct air carbon capture system according to claim 3, 4 or 5, characterized in that: The output end of the DAC adsorption system includes an air exhaust output end after CO2 removal and a high humidity CO2 output end.

8. The water-saving direct air carbon capture system according to claim 7, characterized in that: The high-humidity CO2 output end is connected to the gas storage tank (10) after condensation and water removal through the second pipeline in the condenser (6).

9. A method for operating a water-saving direct air carbon capture system, applicable to the system according to claims 1-8, characterized in that: The following steps are involved: S1. Ambient air is introduced into the air water intake system to absorb moisture; S2. The dehydrated dry air is introduced into the DAC adsorption system to adsorb CO2. The adsorbed water is then desorbed and condensed for collection. After the DAC adsorption system is saturated with CO2, it uses the collected water for spray desorption; S4. The desorbed high humidity CO2 is introduced into the second pipe of the condenser for condensation and water removal, respectively, to collect water and dry CO2; S5. After desorption, the DAC adsorption system is dried by hot air provided by the fan and then proceeds to the next round of CO2 adsorption.

10. The operating method of a water-saving direct air carbon capture system according to claim 9, characterized in that: The total air flow rate Q1 of the fan, the water vapor flow rate Q2 and the semiconductor heating temperature T are controlled to control the water vapor desorption rate η, so that the water collection period and the CO2 adsorption and desorption period are kept in balance.

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